1 Introduction

1.1 Greetings

The purpose of this manual is to document the California Simulation Engine computer program, CSE. CSE is an hourly building and HVAC simulation program which calculates annual energy requirements for building space conditioning and lighting. CSE is specifically tailored for use as internal calculation machinery for compliance with the California building standards.

CSE is a batch driven program which reads its input from a text file. It is not intended for direct use by people seeking to demonstrate compliance. Instead, it will be used within a shell program or by technically oriented users. As a result, this manual is aimed at several audiences:

1. People testing CSE during its development.

2. Developers of the CSE shell program.

3. Researchers and standards developers who will use the program to explore possible conservation opportunities.

Each of these groups is highly sophisticated. Therefore this manual generally uses an exhaustive, one-pass approach: while a given topic is being treated, everything about that topic is presented with the emphasis on completeness and accuracy over ease of learning.

Please note that CSE is under development and will be for many more months. Things will change and from time to time this manual may be inconsistent with the program.

1.2 Manual Organization

This Introduction covers general matters, including program installation.

Operation documents the operational aspects of CSE, such as command line switches, file naming conventions, and how CSE finds files it needs.

Input Structure documents the CSE input language in general.

Input Data describes all of the specific input language statements.

Output Reports will describe the output reports.

Lastly, Probe Definitions lists all available probes.

1.3 Installation

1.3.1 Hardware and Software Requirements

CSE is a 32-bit Microsoft Windows console application. That is, it runs at the command prompt on Windows Vista, Windows 7, Windows 8, and Windows 10. Memory and disk space requirements depend on the size of projects being modeled, but are generally modest.

To prepare input files, a text editor is required. Notepad will suffice, although a text editor intended for programming is generally more capable. Alternatively, some word processors can be used in “ASCII” or “text” or “non-document” mode.

1.3.2 Installation Procedure

Create a directory on your hard disk with the name \CSE or some other name of your choice. Copy the files into that directory. Add the name of the directory to the PATH environment setting unless you intend to use CSE only from the CSE directory.

2 Operation

2.1 Command Line

CSE is invoked from the command prompt or from a batch file using the following command:

    CSE *inputfile* {*switches*}

where:

inputfile

specifies the name of the text input file for the run(s). If the filename has an extension other than “.cse” (the default), it must be included. The name of the file with weather data for the simulation(s) is given in this file (wfName= statement, see Weather Data Items).

{switches}

indicates zero or more of the following:

• -Dname defines the preprocessor symbol name with the value “”. Useful for testing with #ifdef name, to invoke variations in the simulation without changing the input file. The CSE preprocessor is described “The Preprocessor”.

• -Dname=value defines the preprocessor symbol name with the specified value. Name can then be used in the input file to allow varying the simulation without changing the input file – see “The Preprocessor” for more information. The entire switch should be enclosed in quotes if it contains any spaces – otherwise the command processor will divide it into two arguments and CSE will not understand it.

• -Uname undefines the preprocessor symbol name.

• -ipath;path;path specifies directories where CSE looks for input and include files.

• -b batch mode: suppresses all prompts for user input. Currently there are no prompts implemented in CSE. -b is retained in case prompts are added in the future. It is good practice to include -b in batch script CSE invocations.

• -n suppresses screen display of warning messages. When -n is specified, warning messages are reported only to the error file.

• -p display all the class and member names that can be “probed” or accessed in CSE expressions. “Probes” are described in “Probes”. Use with command processor redirection operator “>” to obtain a report in a file. Inputfile may be given or omitted when -p is given.

• -p1 similar to -p, but displays additional member names that cannot be probed or would not make sense to probe in an input file (development aid).

• -c display all input names.

• -c1 display input names with build-independent details from CSE CULT tables (development aid).

• -c2 display input names with all details from CSE CULT tables (development aid).

• -x specifies report test prefix; see TOP repTestPfx. The -x command line setting takes precedence over the input file value, if any.

• -tnn specifies internal testing option bits (development aid). The following values should be combined bit-wise to determine nn.
  1: Omit directory paths from file names in reports, yielding location-independent report files suitable for text comparison.
  2: Include detailed timing information in the log file (default is summary only).

2.2 Locating Files

As with any program, in order to invoke CSE, the directory containing CSE.EXE must be the current directory, or that directory must be on the operating system path, or you must type the directory path before CSE.

A CSE simulation requires a weather file. The name of the weather file is given in the CSE input file (wfName= statement, see Weather Data Items). The weather file must be in one of the same three places: current directory, directory containing CSE.EXE, or a directory on the operating system path; or, the directory path to the file must be given in the wfName= statement in the usual pathName syntax. ?? Appears that file must be in current directory due to file locating bugs 2011-07

The CSE input file, named on the CSE command line, must be in the current directory or the directory path to it must be included in the command line.

Included input files, named in #include preprocessor directives (see “The Preprocessor”) in the input file, must be in the current directory or the path to them must be given in the #include directive. In particular, CSE will NOT automatically look for included files in the directory containing the input file. The default extension for included files is “.CSE”.

Output files created by default by CSE (error message file, primary report and export files) will be in the same directory as the input file; output files created by explicit command in the input file (additional report and/or export files) will be in the current directory unless another path is explicitly specified in the command creating the file.

2.3 Output File Names

If any error or warning messages are generated, CSE puts them in a file with the same name and path as the input file and extension .ERR, as well as on the screen and, usually, in the primary (default) report file. The exception is errors in the command line: these appear only on the screen. If there are no error or warning messages, any prior file with this name is deleted.

By default, CSE generates an output report file with the same name and path as the input file, and extension “.REP”. This file may be examined with a text editor and/or copied to an ASCII printer. If any exports are specified, they go by default into a file with the same name and path as the input file and extension “.EXP”.

In response to specifications in the input file, CSE can also generate additional report and export files with user-specified names. The default extensions for these are .REP and .CSV respectively and the default directory is the current directory; other paths and extensions may be specified. For more information on report and export files, see REPORTFILE and EXPORTFILE in “Input Data”.

2.4 Errorlevel

CSE sets the command processor ERRORLEVEL to 2 if any error occurs in the session. This should be tested in batch files that invoke CSE, to prevent use of the output reports if the run was not satisfactory. The ERRORLEVEL is NOT set if only warning messages that do not suppress or abort the run occur, but such messages DO create the .ERR file.

3 Input Structure

DRAFT: In the following, any text annotated with ?? indicates areas of uncertainty or probable change. As the program and input language develop, these matters will be resolved.

3.1 Introduction

The CSE Input Language is the fundamental interface to the CSE program. The language has been designed with three objectives in mind:

1. Providing direct access to all program features (including ones included for self-testing), to assist in program development.

2. Providing a set of parametric and expression evaluation capabilities useful for standards development and program testing.

3. Providing a means for other programs, such as an interactive user interface, to transmit input data and control data to the program.

Thus, the language is not intended to be used by the average compliance or simulation user. Instead, it will be used during program development for testing purposes and subsequently for highly technical parametric studies, such as those conducted for research and standards development. In all of these situations, power, reproducibility, and thorough input documentation take precedence over user-friendliness.

CSE reads its input from a file. The file may be prepared by the user with a text editor, or generated by some other program.

3.2 Form of the CSE Data

The data used by CSE consists of objects. Each object is of a class, which determines what the object represents. For example, objects of class ZONE represent thermally distinct regions of the building; each thermally distinct region has its own ZONE object. An object’s class determines what data items or members it contains. For instance, a ZONE object contains the zone’s area and volume. In addition, each object can have a name.

The objects are organized in a hierarchy, or tree-like structure. For example, under each ZONE object, there can be SURFACE objects to represent the walls, floors, and ceilings of the ZONE. Under SURFACEs there can be WINDOW objects to represent glazings in the particular wall or roof. SURFACE is said to be a subclass of the class ZONE and WINDOW a subclass of SURFACE; each individual SURFACE is said to be a subobject of its particular ZONE object. Conversely, each individual SURFACE is said to be owned by its zone, and the SURFACE class is said to be owned by the ZONE class.

The hierarchy is rooted in the one top-level object (or just Top). The top level object contains information global to the entire simulation, such as the start and end dates, as well as all of the objects that describe the building to be simulated and the reports to be printed.

Objects and their required data must be specified by the user, except that Top is predefined. This is done with input language statements. Each statement begins an object (specifying its class and object name) or gives a value for a data member of the object being created. Each object is specified with a group of statements that are usually given together, and the objects must be organized according to the hierarchy. For example, SURFACEs must be specified within ZONEs and WINDOWs within SURFACEs. Each SURFACE belongs to (is a subobject of) the ZONE within which it is specified, and each WINDOW is a subobject of its SURFACE.

The entire hierarchy of CSE classes can be represented as follows, using indentation to indicate subclasses:

TODO: review hierarchy

TOP (Top-level class; object of this class supplied automatically by CSE)
    HOLIDAY
    MATERIAL
    CONSTRUCTION
        LAYER
    METER
    DHWMETER
    IZXFER
    DHWDAYUSE
        DHWUSE
    DHWSYS
        DHWHEATER
        DHWTANK
        DHWPUMP
        DHWLOOP
        DHWLOOPPUMP
        DHWLOOPSEG
            DHWLOOPBRANCH
    DHWSOLARSYS
        DHWSOLARCOLLECTOR
    ZONE
        GAIN
        SURFACE
            WINDOW
                SHADE
                SGDIST
            DOOR
    REPORTFILE
    REPORT
    REPORTCOL
    EXPORTFILE
    EXPORT
    EXPORTCOL

3.3 Overview of CSE Input Language

The CSE Input Language consists of commands, each beginning with a particular word and, preferably, ending with a semicolon. Each command is either an action-command, which specifies some action such as starting a simulation run, or a statement, which creates or modifies an object or specifies a value for a member of an object.

3.3.1 Statements – Overview

A statement that creates an object consists basically of the class name followed by your name for the object to be created. (The name can be omitted for most classes; optional modifying clauses will be described later.) For example,

    ZONE "north";

begins an object of class ZONE; the particular zone will be named “north”. This zone name will appear in reports and error messages, and will be used in other statements that operate on the zone. As well as creating the ZONE, this statement sets CSE to expect statements specifying ZONE data members or ZONE subobjects to follow.

A statement specifying a data member consists of the data member’s name, an = sign, an expression specifying the value, and a terminating semicolon. An expression is a valid combination of operands and operators as detailed later; commonly it is just a number, name, or text enclosed in quotes. For example,

    znVol = 100000;

specifies that the zone has a volume of 100000 cubic feet. (If the statement occurs outside of the description of a ZONE, an error message occurs.) All of the member names for each class are described in the input data section; most of them begin with an abbreviation of the class name for clarity.

The description of a zone or any object except Top can be terminated with the word “END”; but this is not essential; CSE will assume the ZONE ends when you start another ZONE or any object not a subobject of ZONE, or when you specify a member of a higher level class (Top for ZONE), or give an action-command such as RUN.

Statements are free-form; several can be put on a line, or a single statement can occupy several lines. Indentation according to class hierarchy will help make your input file readable. Spaces may be used freely except in the middle of a word or number. Tab characters may be used. Each statement should end with a semicolon. If the semicolon is omitted and the statement and the following statement are both correctly formed, CSE will figure out your intent anyway. But when there is an error, CSE gives clearer error messages when the statements are delimited with semicolons.

Capitalization generally does not matter in input language statements; we like to capitalize class names to make them stand out. Words that differ only in capitalization are NOT distinct to CSE.

Comments (remarks) may be interspersed with commands. Comments are used to make the input file clearer to humans; they are ignored by CSE. A comment introduced with “//” ends at the end of the line; a comment introduced with “/*” continues past the next “*/”, whether on the same line, next line, or many lines down. Additional input language may follow the */ on the same line.

3.3.2 Nested Objects

The following is a brief CSE input file, annotated with comments intended to exemplify how the input language processor follows the object hierarchy when decoding input describing objects and their subobjects.

    // short example file
                            // initially, the current object is Top.
    wfName = "CZ12RV2.CEC"; // give weather file name, a Top member
    begDay = Jan 1;         // start and ...
    endDay = Dec 31;        // ...end run dates: Top members.

    MATERIAL carpet;        // create object of class MATERIAL
    matThk = .296;          // specify 'matThk' member of MATERIAL 'carpet'
    matCond = 1./24;        // give value of 'matCond' for 'carpet'

    CONSTRUCTION slab140C;  /* create object of class CONSTRUCTION, named
                               slab140C. Terminates MATERIAL, because
                               CONSTRUCTION is not a subclass of material
                               in the hierarchy shown in another section** */
      LAYER                 /* start an unnamed object of class LAYER.
                               Since LAYER is a subclass of CONSTRUCTION,
                               this will be a subobject of slab140C. */
        lrMat = carpet;     /* member of the LAYER. Note use of name of
                               MATERIAL object. */
      // (additional layers would be here)

    METER Elec;             /* create METER named Elec;
                               since METER is a subobject of Top,
                               this ends slab140C and its LAYER. */

    ZONE North;             // start a ZONE named North.  Ends METER.
      znArea = 1000;        // specify data members of ZONE North.
      znVol = 10;           // (you don't have to capitalize these as shown.)
      GAIN NorthLights      /* create GAIN object named NorthLights.
                               Creates a subobject of ZONE North. */
        gnPower = 0.01;     // member of NorthLights -- numeric value
        gnMeter = Elec;     // member of NorthLights -- object name value

      znCAir = 3.5;         /* processor knows that znCAir is a member of ZONE;
                               thus this statement terminates the GAIN
                               subobject & continues ZONE 'North'. */

      /*lrMat = ...            would be an error here, because the current
                               object is not a LAYER nor a subobject of LAYER */

    RUN;                    /* initiate simulation run with data given.
                               Terminates ZONE North, since action-commands
                               terminate all objects being constructed. */

** See Form of the CSE Data

3.3.3 Expressions – Overview

Expressions are the parts of statements that specify values – numeric values, string values, object name values, and choice values. Expressions are composed of operators and operands, in a manner similar to many programming languages. The available operators and operands will be described in the section on operators.

Unlike most programming languages, CSE expressions have Variation. Variation is how often a value changes during the simulation run – hourly, daily, monthly, yearly (i.e. does not change during run), etc. For instance, the operand $hour represents the hour of the day and has “hourly” variation. An expression has the variation of its fastest-varying component.

Each data member of each object (and every context in which an expression may be used) has its allowed variability, which is the fastest variation it will accept. Many members allow no variability. For example, begDay, the date on which the run starts, cannot meaningfully change during the run. On the other hand, a thermostat setting can change hourly. Thermostat settings and other scheduled values are specified in CSE with expressions that often make use of variability; there is no explicit SCHEDULE class.

For example, a heating setpoint that was 68 during business hours and 55 at night might be expressed as

    select( $hour > 8 && $hour < 18, 68, default 55)

An example of a complete statement containing the above expression is:

    tuTH = select( $hour > 8 && $hour < 18, 68, default 55);

The preceding is valid a statement if used in a TERMINAL description. The following:

    begDay = select( $hour > 8 && $hour < 18, 68, default 55);

would always get an error message, because begDay (the starting day of the run) will not accept hourly variation, and the expression varies hourly, since it contains $hour. The expression’s variation is considered “hourly” even though it changes only twice a day, since CSE has no variation category between hourly and daily.

CSE’s expression capability may be used freely to make input clearer. For example,

    znVol = 15 * 25 * 8;

meaning that the zone volume is 15 times 25 times 8 is the same to CSE as

    znVol = 3000;

but might be useful to you to tersely indicate that the volume resulted from a width of 15, a length of 25, and a height of 8. Further, if you wished to change the ceiling height to 9 feet, the edit would be very simple and CSE would perform the volume calculation for you.

CSE computes expressions only as often as necessary, for maximum simulation speed. For example,

    tuTH = 68;

causes 68 to be stored in the heating setpoint once at the start of the run only, even though tuTH will accept expressions with variability up to hourly. Furthermore, constant inner portions of variable expressions are pre-evaluated before the run begins.

CSE statements and expressions do not (yet) have user-settable variables in the usual programming language sense. They do, however, have user-defined functions to facilitate using the same computation several places, and preprocessor macros, to facilitate using the same text several places, specifying parametric values in a separate file, etc.

3.3.4 The Preprocessor – Overview

The preprocessor scans and processes input file text before the language processor sees the text. The preprocessor can include (embed) additional files in the input, include sections of input conditionally, and define and expand macros.

Macros are a mechanism to substitute a specified text for each occurrence of a word (the macro name). For example,

    #define ZNWID 20
    #define ZNLEN 30
    . . .

    znArea = ZNWID * ZNLEN;
    znVol  = ZNWID * ZNLEN * 8;

The first line above says that all following occurrences of “ZNWID” are to be replaced with “20” (or whatever follows ZNWID on the same line). The effect of the above is that the zone width and length are specified only one place; if the single numbers are editing, both the zone area and zone volume change to match.

Macros can be especially powerful when combined with the file inclusion feature; the generic building description could be in one file, and the specific values for multiple runs supplied by another file. By also using conditional compilation, the values-specifying file can select from a range of features available in the building description file.

The preprocessor is similar to that of the C programming language, and thus will be familiar to C programmers.

The next section describes the preprocessor in detail. The preprocessor description is followed by sections detailing statements, then expressions.

3.4 The Preprocessor

Note: The organization and wording of this section is based on section A12 of Kernigan and Richie [1988]. The reader is referred to that source for a somewhat more rigorous presentation but with the caution that the CSE input language preprocessor does not completely comply to ANSI C specifications.

The preprocessor performs macro definition and expansion, file inclusion, and conditional inclusion/exclusion of text. Lines whose first non-whitespace character is # communicate with the preprocessor and are designated preprocessor directives. Line boundaries are significant to the preprocessor (in contrast to the rest of the input language in which a newline is simply whitespace), although adjacent lines can be spliced with \, as discussed below. The syntax of preprocessor directives is separate from that of the rest of the language. Preprocessor directives can appear anywhere in an input file and their effects last until the end of the input file. The directives that are supported by the input language preprocessor are the following:

    #if
    #else
    #elif
    #endif
    #ifndef

    #define
    #redefine
    #undef

    #include

3.4.1 Line splicing

If the last character on a line is the backslash \, then the next line is spliced to that line by elimination of the backslash and the following newline. Line splicing occurs before the line is divided into tokens.

Line splicing finds its main use in defining long macros:

    // hourly light gain values:
    #define LIGHT_GAIN       .024, .022, .021, .021, .021, .026, \
                             .038, .059, .056, .060, .059, .046, \
                             .045, .5  , .5  , .05 , .057, .064, \
                             .064, .052, .050, .055, .044, .027

3.4.2 Macro definition and expansion

A directive of the form

    #define _identifier_ _token-sequence_

is a macro definition and causes the preprocessor to replace subsequent instances of the identifier with the given token sequence. Note that the token string can be empty (e.g. #define FLAG).

A line of the form

    #define _identifier_( _identifier-list_) _token-sequence_

where there is no space between the identifier and the (, is a macro with parameters given by the identifier list. The expansion of macros with parameters is discussed below.

Macros may also be defined on the CSE command line, making it possible to vary a run without changing the input files at all. As described in the command line section, macros are defined on the CSE command line using the -D switch in the forms

    -D_identifier_

    -D_identifier_=_token-sequence_

The first form simply defines the name with no token-sequence; this is convenient for testing with #ifdef, #ifndef, or defined(), as described in the section on conditional inclusion of tex. The second form allows an argument list and token sequence. The entire command line argument must be enclosed in quotes if it contains any spaces.

A macro definition is forgotten when an #undef directive is encountered:

    #undef _identifier_

It is not an error to #undef an undefined identifier.

A macro may be re-#defined without a prior #undef unless the second definition is identical to the first. A combined #undef/#define directive is available to handle this common case:

    #redefine _identifier_ _token-sequence_

    #redefine _identifier_( _identifier-list_) _token-sequence_

When a macro is #redefined, it need not agree in form with the prior definition (that is, one can have parameters even if the other does not). It is not an error to #redefine an undefined identifier.

Macros defined in the second form (with parameters) are expanded whenever the preprocessor encounters the macro identifier followed by optional whitespace and a comma-separated parameter list enclosed in parentheses. First the comma separated token sequences are collected; any commas within quotes or nested parentheses do not separate parameters. Then each unquoted instance of the each parameter identifier in the macro definition is replaced by the collected tokens. The resulting string is then repeatedly re-scanned for more defined identifiers. The macro definition and reference must have the same number of arguments.

It is often important to include parentheses within macro definitions to make sure they evaluate properly in all situations. Suppose we define a handy area macro as follows:

    #define AREA(w, h) w*h        // WRONG

Consider what happens when this macro is expanded with arguments 2+3 and 4+1. The preprocessor substitutes the arguments for the parameters, then the input language processor processes the statement containing the macro expansion without regard to the beginning and end of the arguments. The expected result is 25, but as defined, the macro will produce a result of 15. Parentheses fix it:

    #define AREA(w, h) ((w)*(h))  // RIGHT

The outer enclosing set of parentheses are not strictly needed in our example, but are good practice to avoid evaluation errors when the macro expands within a larger expression.

Note 1: The CSE preprocessor does not support the ANSI C stringizing (#) or concatenation (##) operators.

Note 2: Identifiers are case insensitive (unlike ANSI C). For example, the text “myHeight” will be replaced by the #defined value of MYHEIGHT (if there is one).

The preprocessor examples at the end of this section illustrate macro definition and expansion.

3.4.3 File inclusion

Directives of the form

#include "filename" and

#include <filename>

cause the replacement of the directive line with the entire contents of the referenced file. If the filename does not include an extension, a default extension of .INP is assumed. The filename may include path information; if it does not, the file must be in the current directory.

#includes may be nested to a depth of 5.

For an example of the use #includes, please see the preprocessor examples at the end of this section.

3.4.4 Conditional inclusion of text

Conditional text inclusion provides a facility for selectively including or excluding groups of input file lines. The lines so included or excluded may be either CSE input language text or other preprocessor directives. The latter capability is very powerful.

Several conditional inclusion directive involve integer constant expressions. Constant integer expressions are formed according the rules discussed in the section on expressions with the following changes:

1. Only constant integer operands are allowed.

2. All values (including intermediate values computed during expression evaluation) must remain in the 16 bit range (-32768 - 32767). The expression processor treats all integers as signed values and requires signed decimal constants – however, it requires unsigned octal and hexadecimal constants. Thus decimal constants must be in the range -32768 - 32767, octal must be in the range 0 - 0o177777, and hexadecimal in the range 0 - 0xffff. Since all arithmetic comparisons are done assuming signed values, 0xffff < 1 is true (unhappily). Care is required when using the arithmetic comparison operators (<, <=, >=, >).

3. The logical relational operators && and || are not available. Nearly equivalent function can be obtained with & and |.

4. A special operand defined( ) is provided; it is described below.

Macro expansion is performed on constant expression text, so symbolic expressions can be used (see examples below).

The basic conditional format uses the directive

    #if _constant-expression_

If the constant expression has the value 0, all lines following the #if are dropped from the input stream (the preprocessor discards them) until a matching #else, #elif, or #endif directive is encountered.

The defined( identifier ) operand returns 1 if the identifier is the name of a defined macro, otherwise 0. Thus

    #if defined( _identifier_ )

can be used to control text inclusion based on macro flags. Two #if variants that test whether a macro is defined are also available. #ifdef identifier is equivalent to #if defined(identifier) and #ifndef identifier is equivalent to #if !defined(identifier).

Defined(), #ifdef, and #ifndef consider a macro name “defined” even if the body of its definition contains no characters; thus a macro to be tested with one of these can be defined with just

    #define _identifier_

or with just “-Didentifier” on the CSE command line.

Conditional blocks are most simply terminated with #endif, but #else and #elif constant-expression are also available for selecting one of two or more alternative text blocks.

The simplest use of #if is to “turn off” sections of an input file without editing them out:

    #if 0
    This text is deleted from the input stream.
    #endif

Or, portions of the input file can be conditionally selected:

    #define FLRAREA 1000   // other values used in other runs
    #if FLRAREA <= 800
        CSE input language for small zones
    #elif FLRAREA <= 1500
        CSE input language for medium zones
    #else
        CSE input language for large zones
    #endif

Note that if a set of #if … #elif … #elif conditionals does not contain an #else, it is possible for all lines to be excluded.

Finally, it is once again important to note that conditional directives nest, as shown in the following example (indentation is included for clarity only):

    #if 0
        This text is NOT included.
        #if 1
            This text is NOT included.
        #endif
    #else
        This text IS included.
    #endif

3.4.5 Input echo control

By default, CSE echos all input text to the input echo report (see REPORT rpType=INP). #echooff and #echoon allow disabling and re-enabling text echoing. This capability is useful reducing report file size by suppressing echo of, for example, large standard include files.

    ... some input ...   // text sent to the input echo report
    #echooff
       // This text will NOT be sent to the input echo report.
       // However, it IS read and used by CSE.
       // Error messages will be echoed even if #echooff
       ... more input ...
    #echoon         // restore echo

Nesting is supported – each #echoon “undoes” the prior #echooff, but echoing does not resume until the topmost (earliest) #echooff is cancelled. * #echoon has no effect when echoing is already active. * Unmatched #echooffs are ignored – echoing remains disabled through the end of the input stream.

3.4.6 Preprocessor examples

This section shows a few combined examples that demonstrate the preprocessor’s capabilities.

The simplest use of macros is for run parameterization. For example, a base file is constructed that derives values from a macro named FLRAREA. Then multiple runs can be performed using #include:

    // Base file
    ... various input language statements ...

    ZONE main
        znArea = FLRAREA
        znVol  = 8*FLRAREA
        znCAir = 2*FLRAREA ...
        ... various other input language statements ...

    RUN

    CLEAR

The actual input file would look like this:

    // Run with zone area = 500, 1000, and 2000 ft2
    #define FLRAREA 500
    #include "base."
    #redefine FLRAREA 1000
    #include "base."
    #redefine FLRAREA 2000
    #include "base."

Macros are also useful for encapsulating standard calculations. For example, most U-values must be entered without surface conductances, yet many tabulated U-values include the effects of the standard ASHRAE winter surface conductance of 6.00 Btuh/ft²-^oF. A simple macro is very helpful:

    #define UWinter(u)  ( 1/(1/(u)-1/6.00) )

This macro can be used whenever a U-value is required (e.g. SURFACE … sfU=UWinter(.11) … ).

3.5 CSE Input Language Statements

This section describes the general form of CSE input language statements that define objects, assign values to the data members of objects, and initiate actions. The concepts of objects and the class hierarchy were introduced in the section on form of CSE data. Information on statements for specific CSE input language classes and their members is the subject of the input data section.

3.5.1 Object Statements

As we described in a previous section, the description of an object is introduced by a statement containing at least the class name, and usually your chosen name for the particular object. In addition, this section will describe several optional qualifiers and modifying clauses that permit defining similar objects without repeating all of the member details, and reopening a previously given object description to change or add to it.

Examples of the basic object-beginning statement:

    ZONE "North";

    METER "Electric - Cooling";

    LAYER;

As described in the section on nested objects, such a statement is followed by statements giving the object’s member values or describing subobjects of the object. The object description ends when you begin another object that is not of a subclass of the object, or when a member of an embedding (higher level) object previously begun is given, or when END is given.

3.5.1.1 Object Names

An object name consists of up to 63 characters. If you always enclose the name in quotation marks, punctuation and spaces may be used freely; if the name starts with a letter or dollar sign and consists only of letters, digits, underscore, and dollar sign, and is different from all of the words already defined in CSE input language (as listed below in this section), you may omit the quotes. Capitalization, and Leading and trailing spaces and tabs, are always disregarded by input language processor. Names of 0 length, and names containing control characters (ASCII codes 0-31) are not allowed.

Examples of valid names that do not require quotes:

    North
    gas_meter
    slab140E

The following object names are acceptable if always enclosed in quotes:

    "Front Door"
    "M L King Day"
    "123"
    "3.5-inch wall"

We suggest always quoting object names so you won’t have to worry about disallowed words and characters.

Duplicate names result in error messages. Object names must be distinct between objects of the same class which are subobjects of the same object. For example, all ZONE names must be distinct, since all ZONEs are subobjects of Top. It is permissible to have SURFACEs with the same name in different ZONEs – but it is a good idea to keep all of your object names distinct to minimize the chance of an accidental mismatch or a confusing message regarding some other error.

For some classes, such as ZONE, a name is required for each object. This is because several other statements refer to specific ZONEs, and because a name is needed to identify ZONEs in reports. For other classes, the name is optional. The specific statement descriptions in the Input Data Section 5 say which names are required. We suggest always using object names even where not required; one reason is because they allow CSE to issue clearer error messages.

The following reserved words will not work as object names unless enclosed in quotes:

(this list needs to be assembled and typed in)

3.5.1.2 ALTER

ALTER is used to reopen a previously defined object when it is not possible or desired to give the entire description contiguously.

ALTER could be used if you wish to order the input in a special way. For example, SURFACE objects are subobjects of ZONE and are normally described with the ZONE they are part of. However, if you wanted to put all roofs together, you could use input of the general form:

    ZONE "1";  . . .  (zone 1 description)
    ZONE "2";  . . .
    . . .
    ALTER ZONE "1";               // revert to specifying zone 1
        SURFACE "Roof1";  . . .   (describe roof of zone 1)
    ALTER ZONE "2";
        SURFACE "Roof2";  . . .

ALTER can be used to facilitate making similar runs. For example, to evaluate the effect of a change in the size of a window, you might use:

    ZONE "South";
        SURFACE "SouthWall";
        ...
            WINDOW "BigWindow";
                wnHeight = 6;  wnWidth = 20;
    . . .
    RUN;          // perform simulation and generate reports
    // data from simulation is still present unless CLEAR given
    ALTER ZONE "South";
        ALTER SURFACE "SouthWall";
            ALTER WINDOW "BigWindow";
                wnHeight = 4;  wnWidth = 12;  // make window smaller
    RUN;          // perform simulation and print reports again

ALTER also lets you access the predefined “Primary” REPORTFILE and EXPORTFILE objects which will be described in the Input Data Section:

    ALTER REPORTFILE "Primary";    /* open description of object automatically
                                      supplied by CSE -- no other way to access */
        rfPageFmt = NO;            /* Turn off page headers and footers --
                                      not desired when reports are to be
                                      reviewed on screen. */

3.5.1.3 DELETE

DELETE followed by a class name and an object name removes the specified object, and any subobjects it has. You might do this after RUN when changing the data for a similar run (but to remove all data, CLEAR is handier), or you might use DELETE after COPYing (below) an object if the intent is to copy all but certain subobjects.

3.5.1.4 LIKE clause

LIKE lets you specify that an object being defined starts with the same member values as another object already defined. You then need give only those members that are different. For Example:

    MATERIAL "SheetRock";         // half inch gypsum board
        matCond = .0925;          // conductivity per foot
        matSpHt = .26;            // specific heat
        matDens = 50;             // density
        matThk = 0'0.5;           // thickness 1/2 inch
    MATERIAL "5/8 SheetRock" LIKE "SheetRock"; // 5/8" gypsum board
        matThk = 0'0.625;         // thickness 5/8 inch
        // other members same as "SheetRock", need not be repeated

The object named after LIKE must be already defined and must be of the same class as the new object.

LIKE copies only the member values; it does not copy any subobjects of the prototype object. For example, LIKEing a ZONE to a previously defined ZONE does not cause the new zone to contain the surfaces of the prototype ZONE. If you want to duplicate the surfaces, use COPY instead of LIKE.

3.5.1.5 COPY clause

COPY lets you specify that the object being defined is the same as a previously defined object including all of the subobjects of that object. For example,

    . . .
    ZONE "West" COPY "North";
        DELETE WALL "East";
        ALTER WALL "South";
            sfExCnd = ambient;

Specifies a ZONE named “West” which is the same as ZONE North except that it does not contain a copy of West’s East wall, and the South wall has ambient exposure.

3.5.1.6 USETYPE clause

USETYPE followed by the type name is used in creating an object of a type previously defined with DEFTYPE (next section). Example:

    SURFACE "EastWall" USETYPE "IntWall";     // use interior wall TYPE (below)
        sfAzm = 90;                           // this wall faces to the East
        sfArea = 8 * 30;                      // area of each wall is different
        sfAdjZn = "East";                     // zone on other side of wall

Any differences from the type, and any required information not given in the type, must then be specified. Any member specified in the type may be respecified in the object unless FROZEN (see this section) in the type (normally, a duplicate specification for a member results in an error message).

3.5.1.7 DEFTYPE

DEFTYPE is used to begin defining a TYPE for a class. When a TYPE is created, no object is created; rather, a partial or complete object description is stored for later use with DEFTYPE. TYPES facilitate creating multiple similar objects, as well as storing commonly used descriptions in a file to be #included in several different files, or to be altered for multiple runs in comparative studies without changing the including files. Example (boldface for emphasis only):

    DEFTYPE SURFACE "BaseWall"                // common characteristics of all walls
        sfType = WALL;                        // walls are walls, so say it once
        sfTilt = 90;                          // all our walls are vertical;
                                              //  but sfAzm varies, so it is not in TYPE.
        sfU = .83;                            // surf conductance; override if different
        sfModel = QUICK;

    DEFTYPE SURFACE "ExtWall" USETYPE "BaseWall";
        sfExCnd = AMBIENT;                    // other side of wall is outdoors
        sfExAbs = 0.5;                        // member only needed for exterior walls

    DEFTYPE SURFACE "IntWall" USETYPE "BaseWall";   // interior wall
        sfExCnd = ADJZN;                      // user must give sfAdjZn.

In a TYPE as much or as little of the description as desired may be given. Omitting normally-required members does not result in an error message in the type definition, though of course an error will occur at use if the member is not given there.

At use, member values specified in the TYPE can normally be re specified freely; to prevent this, “freeze” the desired member(s) in the type definition with

    FREEZE *memberName*;

Alternately, if you wish to be sure the user of the TYPE enters a particular member even if it is normally optional, use

    REQUIRE *memberName*

Sometimes in the TYPE definition, member(s) that you do not want defined are defined – for example, if the TYPE definition were itself initiated with a statement containing LIKE, COPY, or USETYPE. In such cases the member specification can be removed with

    UNSET *memberName*;

3.5.1.8 END and ENDxxxx

END, optionally followed by an object name, can be used to unequivocally terminate an object. Further, as of July 1992 there is still available a specific word to terminate each type of object, such as ENDZONE to terminate a ZONE object. If the object name is given after END or ENDxxxx, an additional check is performed: if the name is not that of an object which has been begun and not terminated, an error message occurs. Generally, we have found it is not important to use END or ENDxxxx, especially since the member names in different classes are distinct.

3.5.2 Member Statements

As introduced in the section on statements, statements which assign values to members are of the general form:

    *memberName* = *expression*;

The specific member names for each class of objects are given in Section 5; many have already been shown in examples.

Depending on the member, the appropriate type for the expression giving the member value may be numeric (integer or floating point), string, object name, or multiple-choice. Expressions of all types will be described in detail in the section on expressions.

Each member also has its variability (also given in the input data section), or maximum acceptable variation. This is how often the expression for the value can change during the simulation – hourly, daily, monthly, no change (constant), etc. The “variations” were introduced in the expressions overview section and will be further detailed in a section on variation frequencies.

Four special statements, AUTOSIZE, UNSET, REQUIRE, and FREEZE, add flexibility in working with members.

3.5.2.1 AUTOSIZE

AUTOSIZE followed by a member name, sets the member to be sized by CSE. The option to AUTOSIZE a member will be shown under its legal range where it is described in the input data section. AUTOSIZE is only applicable to members describing HVAC system airflows and heating/cooling capacities. If AUTOSIZE is used for any member in the input, input describing design day conditions must also be specified (see TOP Autosizing).

3.5.2.2 UNSET

UNSET followed by a member name is used when it is desired to delete a member value previously given. UNSETing a member resets the object to the same internal state it was in before the member was originally given. This makes it legal to specify a new value for the member (normally, a duplicate specification results in an error message); if the member is required (as specified in the input data section), then an error message will occur if RUN is given without re specifying the member.

Situations where you really might want to specify a member, then later remove it, include:

• After a RUN command has completed one simulation run, if you wish to specify another simulation run without CLEARing and giving all the data again, you may need to UNSET some members of some objects in order to re specify them or because they need to be omitted from the new run. In this case, use ALTER(s) to reopen the object(s) before UNSETing.

• In defining a TYPE (see this section), you may wish to make sure certain members are not specified so that the user must give them or omit them if desired. If the origin of the type (possibly a sequence of DEFTYPEs, LIKEs, and/or COPYs) has defined unwanted members, get rid of them with UNSET.

Note that UNSET is only for deleting members (names that would be followed with an = and a a value when being defined). To delete an entire object, use DELETE (see this section).

3.5.2.3 REQUIRE

REQUIRE followed by a member name makes entry of that member mandatory if it was otherwise optional; it is useful in defining a TYPE (see this section) when you desire to make sure the user enters a particular member, for example to be sure the TYPE is applied in the intended manner. REQUIRE by itself does not delete any previously entered value, so if the member already has a value, you will need to UNSET it. ?? verify

3.5.2.4 FREEZE

FREEZE followed by a member name makes it illegal to UNSET or redefine that member of the object. Note that FREEZE is unnecessary most of the time since CSE issues an error message for duplicate definitions without an intervening UNSET, unless the original definition came from a TYPE (see this section). Situations where you might want to FREEZE one or more members include:

• When defining a TYPE (see this section). Normally, the member values in a type are like defaults; they can be freely overridden by member specifications at each use. If you wish to insure a TYPE is used as intended, you may wish to FREEZE members to prevent accidental misuse.

• When your are defining objects for later use or for somebody else to use (perhaps in a file to be included) and you wish to guard against misuse, you may wish to FREEZE members. Of course, this is not foolproof, since there is at present no way to allow use of predefined objects or types without allowing access to the statements defining them.

3.5.3 Action Commands

CSE has two action commands, RUN and CLEAR.

3.5.3.1 RUN

RUN tells CSE to do an hourly simulation with the data now in memory, that is, the data given in the preceding part of the input file.

Note that CSE does NOT automatically run the simulator; an input file containing no RUN results in no simulation (you might nevertheless wish to submit an incomplete file to CSE to check for errors in the data already entered). The explicit RUN command also makes it possible to do multiple simulation runs in one session using a single input file.

When RUN is encountered in the input file, CSE checks the data. Many error messages involving inconsistencies between member values or missing required members occur at this time. If the data is good, CSE starts the simulation. When the simulation is complete and the reports have been output, CSE continues reading the input file. Statements after the first run can add to or change the data in preparation for another RUN. Note that the data for the first run is NOT automatically removed; if you wish to start over with complete specifications, use CLEAR after RUN.

3.5.3.2 CLEAR

CLEAR removes all input data (objects and all their members) from CSE memory. CLEAR is normally used after RUN, when you wish to perform another simulation run and wish to start clean. If CLEAR is not used, the objects from the prior run’s input remain in memory and may be changed or added to produce the input data for the next simulation run.

3.6 Expressions

Probably the CSE input language’s most powerful characteristic is its ability to accept expressions anywhere a single number, string, object name, or other value would be accepted. Preceding examples have shown the inputting zone areas and volumes as numbers (some defined via preprocessor macros) with *’s between them to signify multiplication, to facilitate changes and avoid errors that might occur in manual arithmetic. Such expressions, where all operands are constants, are acceptable anywhere a constant of the same type would be allowed.

But for many object members, CSE accepts live expressions that vary according to time of day, weather, zone temperatures, etc. (etc., etc., etc.!). Live expressions permit simulation of many relationships without special-purpose features in the language. Live expressions support controlling setpoints, scheduling HVAC system operation, resetting air handler supply temperature according to outdoor temperature, and other necessary and foreseen functions without dedicated language features; they will also support many unforeseen user-generated functionalities that would otherwise be unavailable.

Additional expression flexibility is provided by the ability to access all of the input data and much of the internal data as operands in expressions (probes, see this section).

As in a programming language, CSE expressions are constructed from operators and operands; unlike most programming languages, CSE determines how often an expression’s operands change and automatically compute and store the value as often as necessary.

Expressions in which all operands are known when the statement is being decoded (for example, if all values are constants) are always allowed, because the input language processor immediately evaluates them and presents the value to the rest of the program in the same manner as if a single number had been entered. Most members also accept expressions that can be evaluated as soon as the run’s input is complete, for example expressions involving a reference to another member that has not been given yet. Expressions that vary during the run, say at hourly or daily intervals, are accepted by many members. The variability or maximum acceptable variation for each member is given in the descriptions in the input data section, and the variation of each non-constant expression component is given in its description in this section.

Interaction of expressions and the preprocessor: Generally, they don’t interact. The preprocessor is a text processor which completes its work by including specified files, deleting sections under false #if’s, remembering define definitions, replacing macro calls with the text of the definition, removing preprocessor directives from the text after interpreting them, etc., then the resulting character stream is analyzed by the input language statement compiler. However, the if statement takes an integer numeric expression argument. This expression is similar to those described here except that it can only use constant operands, since the preprocessor must evaluate it before deciding what text to feed to the input statement statement compiler.

3.6.1 Expression Types

The type of value to which an expression must evaluate is specified in each member description (see the input data section) or other context in which an expression can be used. Each expression may be a single constant or may be made up of operators and operands described in the rest of this section, so long as the result is the required type or can be converted to that type by CSE, and its variation is not too great for the context. The possible types are:

float	A real number (3.0, 5.34, -2., etc.). Approximately 7 digits are carried internally. If an int is given where a real is required, it is automatically converted.
int	An integer or whole number (-1, 0, 1, 2 etc.). If a real is given, an error may result, but we should change it to convert it (discarding any fractional part).
Boolean	Same as int; indicates that a 0 value will be interpreted as “false” and any non-0 value will be interpreted as “true”.
string	A string of characters; for example, some text enclosed in quotes.
object name	Name of an object of a specified class. Differs from string in that the name need not be enclosed in quotes if it consists only of letters, digits, _, and $, begins with a non-digit, and is different from all reserved words now in or later added to the language (see Object Names).
	The object may be defined after it is referred to. An expression using conditional operators, functions, etc. may be used provided its value is known when the RUN action command is reached.; no members requiring object names accept values that vary during the simulation.
choice	One of several choices; a list of the acceptable values is given wherever a choice is required. The choices are usually listed in CAPITALS but may be entered in upper or lower case as desired. As with object names, quotes are allowed but not required.
	Expressions may be used for choices, subject to the variability of the context.
date	May be entered as a 3-letter month abbreviation followed by an int for the day of the month, or an int for the Julian day of the year (February is assumed to have 28 days). Expressions may be used subject to variability limitations. Examples:
	Jan 23 // January 23
	23 // January 23
	32 // February 1

These words are used in following descriptions of contexts that can accept more than one basic type:

numeric	float or int. When floats and ints are intermixed with the same operator or function, the result is float.
anyType	Any type; the result is the same type as the argument. If floats and ints are intermixed, the result is float. If strings and valid choice names are intermixed, the result is choice. Other mixtures of types are generally illegal, except in expressions for a few members that will accept either one of several choices or a numeric value.

The next section describes the syntax of constants of the various data types; then, we will describe the available operators, then other operand types such as system variables and built-in functions.

3.6.2 Constants

This section reviews how to enter ordinary non-varying numbers and other values.

int	optional - sign followed by digits. Don’t use a decimal point if your intent is to give an int quantity – the decimal point indicates a float to CSE. Hexadecimal and Octal values may be given by prefixing the value with 0x and 0O respectively (yes, that really is a zero followed by an ‘O’).
float	optional - sign, digits and decimal point. Very large or small values can be entered by following the number with an “e” and a power of ten. Examples;
	1.0 1. .1 -5534.6 123.e25 4.56e-23
	The decimal point indicates a float as opposed to an int. Generally it doesn’t matter as CSE converts ints to floats as required, but be careful when dividing: CSE interprets “2/3” as integer two divided by integer 3, which will produce an integer 0 before CSE notices any need to convert to float. If you mean .6666667, say 2./3, 2/3., or .6666667.
feet and inches	Feet and inches may be entered where a float number of feet is required by typing the feet (or a 0 if none), a single quote ’, then the inches. (Actually this is an operator meaning “divide the following value by 12 and add it to the preceding value”, so expressions can work with it.) Examples:
	3'6 0'.5 (10+20)'(2+3)
string	“Text” – desired characters enclosed in double quotes. Maximum length 80 characters (make 132??). To put a " within the “’s, precede it with a backslash. Certain control codes can be represented with letters preceded with a backslash as follows:
	\\e escape
	\\t tab
	\\f form feed
	\\r carriage return
	\\n newline or line feed
object name	Same as string, or without quotes if name consists only of letters, digits, _, and $, begins with a non-digit, and is different from all reserved words now in or later added to the language (see Object Names). Control character codes (ASCII 0-31) are not allowed.
choice	Same as string; quotes optional on choice words valid for the member. Capitalization does not matter.
date	Julian day of year (as int constant), or month abbreviation
	Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov De c
	followed by the int day of month. (Actually, the month names are operators implemented to add the starting day of the month to the following int quantity).

3.6.3 Operators

For floats and ints, the CSE input language recognizes a set of operators based closely on those found in the C programming language. The following table describes the available numeric operators. The operators are shown in the order of execution (precedence) when no ()’s are used to control the order of evaluation; thin lines separate operators of equal precedence.

Operator	Name	Notes and Examples
’	Feet-Inches Separator	a ’ b yields a + b/12; thus 4’6 = 4.5.
+	Unary plus	The familiar “positive”, as in +3. Does nothing; rarely used.
-	Unary minus	The familiar “minus”, as in -3. -(-3) = +3 etc.
!	Logical NOT	Changes 0 to 1 and any non-0 value to 0. !0 = 1, !17 = 0.
~	One’s complement	Complements each bit in an int value.
*	Multiplication	Multiplication, e.g. 3*4 = 12; 3.24*18.54 = 60.07
/	Division	Division, e.g. 4/2 = 2, 3.24/1.42 = 2.28. Integer division truncates toward 0 (e.g. 3/2 = 1, 3/-2 = -1, -3/2 = -1, 2/3 = 0) CAUTION!
%	Modulus	Yields the remainder after division, e.g. 7%2 = 1. The result has the same sign as the left operand (e.g.(-7)%2 = -1). % is defined for both integer and floating point operands (unlike ANSI C).
+	Addition	Yields the sum of the operands, e.g. 5+3 = 8
-	Subtraction	Yields the difference of the operands, e.g. 5-3 = 2
>>	Right shift	a >> b yields a shifted right b bit positions, e.g. 8>>2 = 2
<<	Left shift	a << b yields a shifted left b bit positions, e.g. 8<<2 = 32
<	Less than	a < b yields 1 if a is less than b, otherwise 0
<=	Less than or equal	a <= b yields 1 if a is less than or equal to b, otherwise 0
>=	Greater than or equal	a >= b yields 1 if a is greater than or equal to b, otherwise 0
>	Greater than	a > b yields 1 if a is greater than b, otherwise 0
==	Equal	a == b yields 1 if a is exactly (bit wise) equal to b, otherwise 0
!=	Not equal	a != b yields 1 if a is not equal to b, otherwise 0
&	Bitwise and	a & b yields the bitwise AND of the operands, e.g. 6 & 2 = 2.
^	Bitwise exclusive or	a ^ b yields the bitwise XOR of the operands, e.g. 6 ^ 2 = 4.
|	Bitwise inclusive or	a | b yields the bitwise IOR of the operands, e.g. 6 | 2 = 6.
&&	Logical AND	a && b yields 1 if both a and b are non-zero, otherwise 0. && guarantees left to right evaluation: if the first operand evaluates to 0, the second operand is not evaluated and the result is 0.
||	Logical OR	a || b yields 1 if either a or b is true (non-0), otherwise 0. || guarantees left to right evaluation: if the first operand evaluates to non-zero, the second operand in not evaluated and the result is 1.
? :	Conditional	a ? b : c yields b if a is true (non-0), otherwise c.

Dates are stored as ints (the value being the Julian day of the year), so all numeric operators could be used. The month abbreviations are implemented as operators that add the first day of the month to the following int value; CSE does not disallow their use in other numeric contexts.

For strings, object names, and choices, the CSE input language currently has no operators except the ?: conditional operator. A concatenation operator is being considered. Note, though, that the choose, choose1, select, and hourval functions described below work with strings, object names, and choice values as well as numbers.

3.6.4 System Variables

System Variables are built-in operands with useful values. To avoid confusion with other words, they begin with a $. Descriptions of the CSE system variables follow. Capitalization shown need not be matched. Most system variables change during a simulation run, resulting in the variations shown; they cannot be used where the context will not accept variation at least this fast. (The Input Data Section gives the variability, or maximum acceptable variation, for each object member.)

$dayOfYear	Day of year of simulation, 1 - 365; 1 corresponds to Jan-1. (Note that this is not the day of the simulation unless begDay is Jan-1.) Variation: daily.
$month	Month of year, 1 - 12. Variation: monthly.
$dayOfMonth	Day of month, 1 - 31. Variation: daily.
$hour	Hour of day, 1 - 24, in local time; 1 corresponds to midnight - 1 AM. Variation: hourly.
$hourST	Hour of day, 1 - 24, in standard time; 1 corresponds to midnight - 1 AM. Variation: hourly.
$subhour	Subhour of hour, 1 - N (number of subhours). Variation: subhourly.
$dayOfWeek	Day of week, 1 - 7; 1 corresponds to Sunday, 2 to Monday, etc. Variation: daily.
$DOWH	Day of week 1-7 except 8 on every observed holiday. Variation: daily.
$isHoliday	1 on days that a holiday is observed (regardless of the true date of the holiday); 0 on other days. Variation: daily.
$isHoliTrue	1 on days that are the true date of a holiday, otherwise 0. Variation: daily.
$isWeHol	1 on weekend days or days that are observed as holidays. Variation: daily.
$isWeekend	1 on Saturday and Sunday, 0 on any day from Monday to Friday. Variation: daily.
$isWeekday	1 on Monday through Friday, 0 on Saturday and Sunday. Variation: daily.
$isBegWeek	1 for any day immediately following a weekend day or observed holiday that is neither a weekend day or an observed holiday. Variation: daily.
$isWorkDay	1 on non-holiday Monday through Friday, 0 on holidays, Saturday and Sunday. Variation: daily.
$isNonWorkDay	1 on Saturday, Sunday and observed holidays, 0 on non-holiday Monday through Friday. Variation: daily.
$isBegWorkWeek	1 on the first workday after a non-workday, 0 all other days. Variation: daily.
$isDT	1 if Daylight Saving time is in effect, 0 otherwise. Variation: hourly.
$autoSizing	1 during autosizing calculations, 0 during main simulation. Variation: for each phase.
$dsDay	Design day type, 0 during main simulation, 1 during heating autosize, 2 during cool autosize. Variation: daily.

Weather variables: the following allow access to the current hour’s weather conditions in you CSE expressions. Units of measure are shown in parentheses. All have Variation: hourly.

$radBeam	Solar beam irradiance (on a sun-tracking surface) this hour (Btu/ft2)
$radDiff	Solar diffuse irradiance (on horizontal surface) this hour (Btu/ft2)
$tDbO	Outdoor drybulb temperature this hour (degrees F)
$tWbO	Outdoor wetbulb temperature this hour (degrees F)
$wO	Outdoor humidity ratio this hour (lb H2O/lb dry air)
$windDirDeg	Wind direction (compass degrees)
$windSpeed	Wind speed (mph)

3.6.5 Built-in Functions

Built-in functions perform a number of useful scheduling and conditional operations in expressions. Built-in functions have the combined variation of their arguments; for hourval, the minimum result variation is hourly. For definitions of numeric and anyType, see Expression Types.

3.6.5.1 brkt

Function	limits a value to be in a given range
Syntax	numeric brkt( numeric min, numeric val, numeric max)
Remark	If val is less than min, returns min; if val is greater than max, returns max; if val is in between, returns val.
Example	In an AIRHANDLER object, the following statement would specify a supply temperature equal to 130 minus the outdoor air temperature, but not less than 55 nor greater than 80:
	ahTsSp = brkt( 55, 130 - $tDbO, 80);
	This would produce a 55-degree setpoint in hot weather, an 80-degree setpoint in cold weather, and a transition from 55 to 70 as the outdoor temperature moved from 75 to 50.

3.6.5.2 fix

Function	converts float to int
Syntax	int fix( float val )
Remark	val is converted to int by truncation – fix( 1.3) and fix( 1.99) both return 1. fix( -4.4) returns -4.

3.6.5.3 toFloat

Function	converts int to float
Syntax	float toFloat( int val )

3.6.5.4 min

Function	returns the lowest quantity from a list of values.
Syntax	numeric min( numeric value1, numeric value2, … numeric valuen )
Remark	there can be any number of arguments separated by commas; if floats and ints are intermixed, the result is float.

3.6.5.5 max

Function	returns the highest quantity from a list of values.
Syntax	numeric max ( numeric value1, numeric value2, … numeric valuen )

3.6.5.6 choose

Function	returns the nth value from a list. If arg0 is 0, value0 is returned; for 1, value1 is returned, etc.
Syntax	anyType choose ( int arg0, anyType value0, anyType value1, … anyType valuen ) or anyType choose ( int arg0, anyType value0, … anyType valuen, default valueDef)
Remarks	Any number of value arguments may be given. If default and another value is given, this value will be used if arg0 is less than 0 or too large; otherwise, an error will occur.

3.6.5.7 choose1

Function	same as choose except arg0 is 1-based. Choose1 returns the second argument value1 for arg0 = 1, the third argument value2 when arg0 = 2, etc.
Syntax	anyType choose1 ( int arg0, anyType value1, anyType value2, … anyType valuen ) or anyType choose1 ( int arg0, anyType value1, … anyType valuen, default valueDef)
Remarks	choose1 is a function that is well suited for use with daily system variables. For example, if a user wanted to denote different values for different days of the week, the following use of choose1 could be implemented:
	tuTC = choose1(\$dayOfWeek, MonTemp, TueTemp, ...)
	Note that for hourly data, the hourval function would be a better choice, because it doesn’t require the explicit declaration of the $hour system variable.

3.6.5.8 select

Function	contains Boolean-value pairs; returns the value associated with the first Boolean that evaluates to true (non-0).
Syntax	anyType ( Boolean arg1, anyType value1, Boolean arg2, anyType value2, … default anyType) (the default part is optional)
Remark	select is a function that simulates if-then logic during simulation (for people familiar with C, it works much like a series of imbedded conditionals: (a?b:(a?b:c)) ).
Examples	Select can be used to simulate a dynamic (run-time) if-else statement:
	gnPower = select( $isHoliday, HD_GAIN, // if ($isHolid a y)
	default WD_GAIN) // else
	This technique can be combined with other functions to schedule items on a hourly and daily basis. For example, an internal gain that has different schedules for holidays, weekdays, and weekends could be defined as follows:
	// 24-hour lighting power schedules for weekend, weekda y , holiday:
	#define WE_LIGHT hourval( .024, .022, .021, .021, .021 , . 026, \
	.038, .059, .056, .060, .059, .046, \
	.045, .005, .005, .005, .057, .064, \
	.064, .052, .050, .055, .044, .027 )
	#define WD_LIGHT hourval( .024, .022, .021, .021, .021 , . 026, \
	.038, .059, .056, .060, .059, .046, \
	.045, .005, .005, .005, .057, .064, \
	.064, .052, .050, .055, .044, .027 )
	#define HD_LIGHT hourval( .024, .022, .021, .021, .021 , . 026, \
	.038, .059, .056, .060, .059, .046, \
	.045, .005, .500, .005, .057, .064, \
	.064, .052, .050, .055, .044, .027 )
	// set power member of zone's GAIN object for lighting
	gnPower = BTU_Elec( ZAREA*0.1 ) * // .1 kW/ft2 ti mes...
	select( $isHoliday, HD_LIGHT, // Holidays
	$isWeekend, WE_LIGHT, // Saturday & Sunday
	default WD_LIGHT ); // Week Days
	In the above, three subexpressions using hourval (next) are first defined as macros, for ease of reading and later change. Then, gnPower (the power member of a GAIN object) is set, using select to choose the appropriate one of the three hourval calls for the type of day. The expression for gnPower is a live expression with hourly variation, that is, CSE will evaluate it an set gnPower to the latest value each hour of the simulation. The variation comes from hourval, which varies hourly (also, $isHoliday and $isWeekend vary daily, but the faster variation determines the variation of the result).

3.6.5.9 hourval

Function	from a list of 24 values, returns the value corresponding to the hour of day.
Syntax	anyType hourval ( anyType value1, anyType value2, … anyType value24 )
	anyType hourval ( anyType value1, anyType value2, … default anyType)
Remark	hourval is evaluated at runtime and uses the hour of the day being simulated to choose the corresponding value from the 24 suppplied values.
	If less than 24 value arguments are given, default and another value (or expression) should be supplied to be used for hours not explicitly specified.
Example	see select, just above.

3.6.5.10 abs

Function	converts numeric to its absolute value
Syntax	numeric abs( numeric val)

3.6.5.11 sqrt

Function	Calculates and returns the positive square root of val ( val must be \(\geq\) 0).
Syntax	float sqrt ( float val)

3.6.5.12 exp

Function	Calculates and returns the exponential of val (= eval)
Syntax	float exp( float val)

3.6.5.13 logE

Function	Calculates and returns the base e logarithm of val ( val must be \(\geq\) 0).
Syntax	float logE( float val)

3.6.5.14 log10

Function	Calculates and returns the base 10 logarithm of val ( val must be \(\geq\) 0).
Syntax	float log10( float val)

3.6.5.15 sin

Function	Calculates and returns the sine of val (val in radians)
Syntax	float sin( float val)

3.6.5.16 sind

Function	Calculates and returns the sine of val (val in degrees)
Syntax	float sind( float val)

3.6.5.17 asin

Function	Calculates and returns (in radians) the arcsine of val
Syntax	float asin( float val)

3.6.5.18 asind

Function	Calculates and returns (in degrees) the arcsine of val
Syntax	float asind( float val)

3.6.5.19 cos

Function	Calculates and returns the cosine of val (val in radians)
Syntax	float cos( float val)

3.6.5.20 cosd

Function	Calculates and returns the cosine of val (val in degrees)
Syntax	float cosd( float val)

3.6.5.21 acos

Function	Calculates and returns (in radians) the arccosine of val
Syntax	float acos( float val)

3.6.5.22 acosd

Function	Calculates and returns (in degrees) the arccosine of val
Syntax	float acosd( float val)

3.6.5.23 tan

Function	Calculates and returns the tangent of val (val in radians)
Syntax	float tan( float val)

3.6.5.24 tand

Function	Calculates and returns the tangent of val (val in degrees)
Syntax	float tand( float val)

3.6.5.25 atan

Function	Calculates and returns (in radians) the arctangent of val
Syntax	float atan( float val)

3.6.5.26 atand

Function	Calculates and returns (in degrees) the arctangent of val
Syntax	float atand( float val)

3.6.5.27 atan2

Function	Calculates and returns (in radians) the arctangent of y/x (handling x = 0)
Syntax	float atan2( float y, float x)

3.6.5.28 atan2d

Function	Calculates and returns (in degrees) the arctangent of y/x (handling x = 0)
Syntax	float atan2d( float y, float x)

3.6.5.29 pow

Function	Calculates and returns val raised to the xth power (= valx). val and x cannot both be 0. If val < 0, x must be integral.
Syntax	float pow( float val, numeric x)

3.6.5.30 enthalpy

Function	Returns enthalpy of moist air (Btu/lb) for dry bulb temperature (F) and humidity ratio (lb/lb)
Syntax	float enthalpy( float tDb, float w)

3.6.5.31 wFromDbWb

Function	Returns humidity ratio (lb/lb) of moist air from dry bulb and wet bulb temperatures (F)
Syntax	float wFromDbWb( float tDb, float tWb)

3.6.5.32 wFromDbRh

Function	Returns humidity ratio (lb/lb) of moist air from dry bulb temperature (F) and relative humidity (0 – 1)
Syntax	float wFromDbRh( float tDb, float rh)

3.6.5.33 rhFromDbW

Function	Returns relative humidity (0 – 1) of moist air from dry bulb temperature (F) and humidity ratio (lb/lb).
Syntax	float rhFromDbW( float tDb, float w)
Remark	The return value is constrained to 0 <= rh <= 1 (that is, physically impossible combinations of tDb and w are silently tolerated).

3.6.5.34 import

Function	Returns float read from an import file.
Syntax	float import( string importFile, string colName) float import( string importFile, int colN)
Remark	Columns can be referenced by name or 1-based index. See IMPORTFILE for details on use of import()

3.6.5.35 importStr

**Functio n	Returns string read from an import file.
Syntax	string importStr( string importFile, string colName) string importStr( string importFile, int colN)
Remark	See IMPORTFILE for details on use of importStr()

3.6.5.36 contin

Function	Returns continuous control value, e.g. for lighting control
Syntax	float contin( float mpf, float mlf, float sp, float val)
Remark	contin is evaluated at runtime and returns a value in the range 0 – 1 ???
Example	–

3.6.5.37 stepped

Function	Returns stepped reverse-acting control value, e.g. for lighting control
Syntax	float stepped( int nsteps, float sp, float val)
Remark	stepped is evaluated at runtime and returns a value in the range 0 – 1. If val <= 0, 1 is returned; if val >= sp, 0 is returned; otherwise, a stepped intermediate value is returned (see example)

example:

stepped( 3, 12, val) returns

val	result
val \(<\) 4	1
4 \(\leq\) val \(<\) 8	.667
8 \(\leq\) val \(<\) 12	.333
val \(\geq\) 12	0

3.6.6 User-defined Functions

User defined functions have the format:

    type FUNCTION name ( arg decls ) = expr ;

Type indicates the type of value the function returns, and can be:

    INTEGER
    FLOAT
    STRING
    DOY       (day of year date using month name and day; actually same as integer).

Arg decls indicates zero or more comma-separated argument declarations, each consisting of a type (as above) and the name used for the argument in expr.

Expr is an expression of (or convertible to) type.

The tradeoffs between using a user-defined function and a preprocessor macro (#define) include:

1. Function may be slightly slower, because its code is always kept separate and called, while the macro expansion is inserted directly in the input text, resulting in inline code.

2. Function may use less memory, because only one copy of it is stored no matter how many times it is called.

3. Type checking: the declared types of the function and its arguments allow CSE to perform additional checks.

Note that while macros require line-splicing (“\”)to extend over one line, functions do not require it:

    // Function returning number of days in ith month of year:
    DOY FUNCTION MonthLU (integer i) = choose1 ( i , Jan 31, Feb 28, Mar 31,
                                                     Apr 30, May 31, Jun 30,
                                                     Jul 31, Aug 31, Sep 30,
                                                     Oct 31, Nov 30, Dec 31 ) ;
    // Equivalent preprocessor macro:
    #define MonthLU (i) = choose1 ( i , Jan 31, Feb 28, Mar 31,  \
                                        Apr 30, May 31, Jun 30,  \
                                        Jul 31, Aug 31, Sep 30,  \
                                        Oct 31, Nov 30, Dec 31 ) ;

3.6.7 Probes

Probes provide a universal means of referencing data within the simulator. Probes permit using the inputtable members of each object, as described in the Input Data Section, as operands in expressions. In addition, most internal members can be probed; we will describe how to find their names shortly.

Three general ways of using probes are:

1. During input, to implement things like “make this window’s width equal to 10% of the zone floor area” by using the zone’s floor area in an expression:

    wnWidth = @zone[1].znArea * 0.1;

Here “@zone[1].znArea” is the probe.

2. During simulation. Probing during simulation, to make inputs be functions of conditions in the building or HVAC systems, is limited because most of the members of interest are updated after CSE has evaluated the user’s expressions for the subhour or other time interval – this is logically necessary since the expressions are inputs. (An exception is the weather data, but this is also available through system variables such as $tDbO.)

However, a number of prior subhour values are available for probing, making it possible to implement relationships like “the local heat output of this terminal is 1000 Btuh if the zone temperature last subhour was below 65, else 500”:

    tuMnLh = @znres["North"].S.prior.tAir < 65 ? 1000 : 500;

3. For output reports, allowing arbitrary data to be reported at subhourly, hourly, daily, monthly, or annual intervals. The REPORT class description describes the user-defined report type (UDT), for which you write the expression for the value to be reported. With probes, you can thus report almost any datum within CSE – not just those values chosen for reporting when the program was designed. Even values calculated during the current subhour simulation can be probed and reported, because expressions for reports are evaluated after the subhour’s calculations are performed.

Examples:

    colVal = @airHandler["Hot"].ts;     // report air handler supply temp
    colVal = @terminal[NorthHot].cz;    // terminal air flow to zone (Btuh/F)

The general form of a probe is

    @ className [ objName ] . member

The initial @ is always necessary. And don’t miss the period after the ].

className is the CLASS being probed

objName	is the name of the specific object of the class; alternately, a numeric subscript is allowed. Generally, the numbers correspond to the objects in the order created. [ objName ] can be omitted for the TOP class, which has only one member, Top.
member	is the name of the particular member being probed. This must be exactly correct. For some inputtable members, the probe name is not the same as the input name given in the Input Data Section, and there are many probe-able members not described in the Input Data section.

How do you find out what the probe-able member names are? CSE will display the a list of the latest class and member names if invoked with the -p switch. Use the command line

    CSE -p >probes.txt

to put the displayed information into the file PROBES.TXT, then print the file or examine it with a text editor.

A portion of the -p output looks like:

    @exportCol[1..].        I   R                   owner: export
                     name   I   R   string            constant
                  colHead   I   R   string            input time
                   colGap   I   R   integer number    input time
                   colWid   I   R   integer number    input time
                   colDec   I   R   integer number    input time
                  colJust   I   R   integer number    constant
                   colVal   I   R   un-probe-able     end of each subhour
                   nxColi   I   R   integer number    constant

    @holiday[1..].          I
                     name   I       string            constant
               hdDateTrue   I       integer number    constant
                hdDateObs   I       integer number    constant
               hdOnMonday   I       integer number    constant

In the above “exportCol” and “holiday” are class names, and “name”, “colHead”, “colGap”, . . . are member names for class exportCol. Some members have multiple names separated by .’s, or they may contain an additional subscript. To probe one of these, type all of the names and punctuation exactly as shown (except capitalization may differ); if an additional subscript is shown, give a number in the specified range. An “I” designates an “input” parameter, an R means “runtime” parameter. The “owner” is the class of which this class is a subclass.

The data type and variation of each member is also shown. Note that variation, or how often the member changes, is shown here. (Variability, or how often an expression assigned to the member may change, is given for the input table members in the Input Data Section). Members for which an “end of” variation is shown can be probed only for use in reports. A name described as “un-probe-able” is a structure or something not convertible to an integer, float, or string.

surface[].sgdist[].f[]: f[0] is winter solar coupling fraction; f[1] is summer.

3.6.8 Variation Frequencies Revisited

At risk of beating the topic to death, we’re going to review once more the frequencies with which a CSE value can change (variations), with some comments on the corresponding variabilities.

subhourly	changes in each “subhour” used in simulation. Subhours are commonly 15-minute intervals for models using znModel=CNE or 2-minute intervals for CSE znModels.
hourly	changes every simulated hour. The simulated weather and many other aspects of the simulation change hourly; it is customary to schedule setpoint changes, HVAC system operation, etc. in whole hours.
daily	changes at each simulated midnite.
monthly	changes between simulated months.
monthly-hourly, or “hourly on first day of each month”	changes once an hour on the first day of each month; the 24 hourly values from the first day of the month are used for the rest of the month. This variation and variability is used for data dependent on the sun’s position, to save calculation time over computing it every hour of every day.
run start time	value is derived from other inputs before simulation begins, then does not change.
	Members that cannot change during the simulation but which are not needed to derive other values before the simulation begins have “run start time” variability.
input time	value is known before CSE starts to check data and derive “run start time” values.
	Expressions with “input time” variation may be used in many members that cannot accept any variation during the run. Many members documented in the Input Data Section as having “constant” variability may actually accept expressions with “input time” variation; to find out, try it: set the member to an expression containing a proposed probe and see if an error message results.
	“Input time” differs from “constant” in that it includes object names (forward references are allowed, and resolved just before other data checks) and probes that are forward references to constant values.
constant	does not vary. But a “constant” member of a class denoted as R (with no I) in the probes report produced by CSE -p is actually not available until run start time.

Also there are end-of varieties of all of the above; these are values computed during simulation: end of each hour, end of run, etc. Such values may be reported (using a probe in a UDT report), but will produce an error message if probed in an expression for an input member value.

4 Input Data

This section describes the input for each CSE class (object type). For each object you wish to define, the usual input consists of the class name, your name for the particular object (usually), and zero or more member value statements of the form name=expression. The name of each subsection of this section is a class name (HOLIDAY, MATERIAL, CONSTRUCTION, etc.). The object name, if given, follows the class name; it is the first thing in each description (hdName, matName, conName, etc.). Exception: no statement is used to create or begin the predefined top-level object “Top” (of class TOP); its members are given without introduction.

After the object name, each member’s description is introduced with a line of the form name=type. Type indicates the appropriate expression type for the value:

• float

• int

• string

• ____name (object name for specified type of object)

• choice

• date

These types discussed in the section on expression types.

Each member’s description continues with a table of the form:

Units	Legal Range	Default	Required	Variability
ft2	x > 0	wnHeight * wnWidth	No	constant

where the column headers have the following meaning:

Units	units of measure (lb., ft, Btu, etc.) where applicable
Legal	limits of valid range for numeric inputs; valid choices
Range	for choice members, etc.
Default	value assumed if member not given; applicable only if not required
Required	YES if you must give this member
Variability	how often the given expression can change: hourly, daily, etc. See sections on expressions, statements, and variation frequencies

4.1 TOP Members

The top-level data items (TOP members) control the simulation process or contain data that applies to the modeled building as a whole. No statement is used to begin or create the TOP object; these statements can be given anywhere in the input (they do, however, terminate any other objects being specified – ZONEs, REPORTs, etc.).

4.1.1 TOP General Data Items

doMainSim=choice

Specifies whether the simulation is performed when a Run command is encountered. See also doAutoSize.

Units	Legal Range	Default	Required	Variability
	NO, YES	YES	No	constant

begDay=date

Date specifying the beginning day of the simulation performed when a Run command is encountered. See further discussion under endDay (next).

Units	Legal Range	Default	Required	Variability
	date	Jan 1	No	constant

endDay=date

Date specifying the ending day of the simulation performed when a Run command is encountered.

The program simulates 365 days at most. If begDay and endDay are the same, 1 day is simulated. If begDay precedes endDay in calendar sequence, the simulation is performed normally and covers begDay through endDay inclusive. If begDay follows endDay in calendar sequence, the simulation is performed across the year end, with Jan 1 immediately following Dec 31.

Units	Legal Range	Default	Required	Variability
	date	Dec 31	No	constant

jan1DoW=choice

Day of week on which January 1 falls. jan1DoW is used in the calculation of the day of the week.

Note that “warm-up” days (see wuDays) occur before the start day specified by begDay. Thus “warm-up” days are often in the prior year. In order to preserve the day-of-week sequence, the effective jan1DoW is shifted back by one day during prior-year warmup.

Units	Legal Range	Default	Required	Variability
	SUN, MON, TUE, WED, THU, FRI, SAT	THU	No	constant

workDayMask=int TODO

Units	Legal Range	Default	Required	Variability
				constant

wuDays=int

Number of “warm-up” days used to initialize the simulator. Simulator initialization is required because thermal mass temperatures are set to arbitrary values at the beginning of the simulation. Actual mass temperatures must be established through simulation of a few days before thermal loads are accumulated. Heavier buildings require more warm-up; the default values are adequate for conventional construction.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 365	7	No	constant

nSubSteps=int

Number of subhour steps used per hour in the simulation. 4 is the time-honored value for models using CNE zones. A value of 30 is typically for CSE zone models.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	4	No	constant

nSubhrTicks=int

Number of subhour ticks used per nSubSteps for DHWSYS simulation.

Note: This input is currently used only for experimental purposes.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	60/nSubSteps	No	constant

tol=float

Endtest convergence tolerance for internal iteration in CNE models (no effect for CSE models) Small values for the tolerance cause more accurate simulations but slower performance. The user may wish to use a high number during the initial design process (to quicken the runs) and then lower the tolerance for the final design (for better accuracy). Values other than .001 have not been explored.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.001	No	constant

humTolF=float

Specifies the convergence tolerance for humidity calculations in CNE models (no effect in for CSE models), relative to the tolerance for temperature calculations. A value of .0001 says that a humidity difference of .0001 is about as significant as a temperature difference of one degree. Note that this is multiplied internally by “tol”; to make an overall change in tolerances, change “tol” only.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	0.0001	No	constant

ebTolMon=float

Monthly energy balance error tolerance for internal consistency checks. Smaller values are used for testing the internal consistency of the simulator; values somewhat larger than the default may be used to avoid error messages when it is desired to continue working despite a moderate degree of internal inconsistency.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.0001	No	constant

ebTolDay=float

Daily energy balance error tolerance.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.0001	No	constant

ebTolHour=float

Hourly energy balance error tolerance.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.0001	No	constant

ebTolSubhr=float

Sub-hourly energy balance error tolerance.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.0001	No	constant

unMetTzTol=float

Zone temperature unmet load tolerance. At the end of each subhour, if a conditioned zone temperature is more than unMetTzTol below the current heating setpoint or more than unMetTzTol above the current cooling setpoint, “unmet load” time is accumulated.

Units	Legal Range	Default	Required	Variability
oF	x \(\geq\) 0	1 oF	No	constant

unMetTzTolWarnHrs=float

Unmet load warning threshold. A warning message is issued for each zone having more than unMetTzTolWarnHrs unmet heating or cooling loads.

Units	Legal Range	Default	Required	Variability
hr	x \(\geq\) 0	150	No	constant

grndMinDim=float

The minimum cell dimension used in the two-dimensional finite difference calculations for FOUNDATIONs.

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	0.066	No	constant

grndMaxGrthCoeff=float

The maximum ratio of growth between neighboring cells in the direction away from the near-field area of interest. Used in the two-dimensional finite difference calculations for FOUNDATIONs.

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 1.0	1.5	No	constant

grndTimeStep=choice

Allows the user to choose whether to calculate foundation conduction on hourly or subhourly intervals. Hourly intervals require less overall computation time, but with less accuracy.

Units	Legal Range	Default	Required	Variability
	HOURLY, SUBHOURLY	HOURLY	No	constant

humMeth=choice

Developmental zone humidity computation method choice for CNE models (no effect for CSE models).

ROB	Rob’s backward difference method. Works well within limitations of backward difference approach.
PHIL	Phil’s central difference method. Should be better if perfectedcoma but initialization at air handler startup is unresolved*coma and ringing has been observed.

Units	Legal Range	Default	Required	Variability
	ROB, PHIL	ROB	No	constant

dflExH=float

Default exterior surface (air film) conductance used for opaque and glazed surfaces exposed to ambient conditions in the absence of explicit specification.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	2.64	No	constant

bldgAzm=float

Reference compass azimuth (0 = north, 90 = east, etc.). All zone orientations (and therefore surface orientations) are relative to this value, so the entire building can be rotated by changing bldgAzm only. If a value outside the range 0^o \(\leq\) x \(<\) 360^o is given, it is normalized to that range.

Units	Legal Range	Default	Required	Variability
o (degrees)	unrestricted	0	No	constant

elevation=float

Elevation of the building site. Used internally for the computation of barometric pressure and air density of the location.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0 (sea level)	No	constant

runTitle=string

Run title for the simulation. Appears in report footers, export headers, and in the title lines to the INP, LOG, and ERR built-in reports (these appear by default in the primary report file; the ERR report also appears in the error message file, if one is created).

Units	Legal Range	Default	Required	Variability
	63 characters	blank (no title	No	constant

runSerial=int

Run serial number for the simulation. Increments on each run in a session; appears in report footers.

Units	Legal Range	Default	Required	Variability
	0 \(leq\) x \(leq\) 999	0	No	constant

4.1.2 TOP Daylight Saving Time Items

Daylight savings starts by default at 2:00 a.m. of the second Sunday in March. Internally, hour 3 (2:00-3:00 a.m.) is skipped and reports for this day show only 23 hours. Daylight savings ends by default at 2:00 a.m. of the first Sunday of November; for this day 25 hours are shown on reports. CSE fetches weather data using standard time but uses daylight savings time to calculate variable expressions (and thus all schedules).

DT=choice

Whether Daylight Savings Time is to be used for the current run.

Units	Legal Range	Default	Required	Variability
	YES, NO	YES	No	constant

DTbegDay=date

Start day for daylight saving time (assuming DT=Yes)

Units	Legal Range	Default	Required	Variability
	date	second Sunday in March	No	constant

DTendDay=date

End day for daylight saving time (assuming DT=Yes)

Units	Legal Range	Default	Required	Variability
	date	first Sunday in November	No	constant

4.1.3 TOP Model Control Items

ventAvail=choice

Indicates availability of outdoor ventilation strategies. CSE cannot model simultaneously-operating alternative ventilation strategies. For example, an RSYS central fan integrated (CFI) OAV system is never modeled while whole house fan ventilation is available. ventAvail controls which ventilation mode, if any, is available for the current hour. Note that mode availability means that the strategy could operate but may not operate due to other control assumptions.

Choice	Ventilation Strategy Available
NONE	None
WHOLEBUILDING	IZXFER (window and whole-house fan)
RSYSOAV	RSYS central fan integrated (CFI) outside air ventilation (OAV)

As noted, ventAvail is evaluated hourly, permitting flexible control strategy modeling. The following example specifies that RSYSOAV (CFI) ventilation is available when the seven day moving average temperature is above 68 ^oF, otherwise whole building ventilation is available between 7 and 11 PM, otherwise no ventilation.

ventAvail = (@weather.taDbAvg07 > 68)    ? RSYSOAV
          : ($hour >= 19 && $hour <= 23) ? WHOLEBUILDING
          :                                NONE

Units	Legal Range	Default	Required	Variability
	Choices above	WHOLEBUILDING	No	hourly

exShadeModel=choice

Specifies advanced exterior shading model used to evaluate shading of PVARRAYs by SHADEXs or other PVARRAYs. Advanced shading is not implemented for building surfaces and this setting has no effect on walls or windows.

Choice	Effect
PENUMBRA	Calculate shading using the Penumbra model
NONE	Disable advanced shading calculations

Units	Legal Range	Default	Required	Variability
	Choices above	PENUMBRA	No	constant

slrInterpMeth=choice

Solar interpolation method.

Choice
CSE
TRNSYS

Units	Legal Range	Default	Required	Variability
	See table above	CSE	No	constant

ANTolAbs=float

AirNet absolute convergence tolerance. Ideally, calculated zone air pressures should be such that the net air flow into each zone is 0 – that is, there should be a perfect mass balance. The iterative AirNet solution techniques are deemed converged when netAirMassFlow < max( ANTolAbs, ANTolRel*totAirMassFlow).

Units	Legal Range	Default	Required	Variability
lbm/sec	x \(>\) 0	0.00125 (about 1 cfm)	No	constant

ANTolRel=float

AirNet relative convergence tolerance. See AnTolAbs just above.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.0001	No	constant

ANPressWarn=float

AirNet pressure warning threshold. A warning message is issued when the absolute value of the AirNet-calculated zone pressure exceeds ANPressWarn. Note the default for ANPressWarn conservatively large. 10 lb/ft2 is about 500 pascals – a pressure that is probably impossible in a building. The intent of this value is to alert the user to incorrect modeling inputs while avoiding excessive messages.

Units	Legal Range	Default	Required	Variability
lb/ft2	x \(\gt\) 0	10	No	constant

ANPressErr=float

AirNet pressure error threshold. The simulation terminates with a message if the absolute value of any AirNet-calculated zone pressure exceeds ANPressErr. Note the default value for ANPressErr is physically unrealistic. 30 lb/ft2 is about 1500 pascals – a pressure that would never be possible in a building. The intent of this value is to prevent simulation crashes due to numerical errors in AirNet calculations.

Units	Legal Range	Default	Required	Variability
lb/ft2	x \(\gt\) 0	30	No	constant

The ASHWAT complex fenestration model used when WINDOW wnModel=ASHWAT yields several heat transfer results that are accurate over local ranges of conditions. Several values control when these value are recalculated. If any of the specified values changes more than the associated threshold, a full ASHWAT calculation is triggered. Otherwise, prior results are used. ASHWAT calculations are computationally expensive and conditions often change only incrementally between time steps.

AWTrigT=float

ASHWAT temperature change threshold – full calculation is triggered by a change of either indoor or outdoor environmental (combined air and radiant) temperature that exceeds AWTrigT.

Units	Legal Range	Default	Required	Variability
oF	x \(>\) 0	1	No	constant

AWTrigSlr=float

ASHWAT solar change threshold – full calculation is triggered by a fractional change of incident solar radiation that exceeds AWTrigSlr.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.05	No	constant

AWTrigH=float

ASHWAT convection coefficient change threshold – full calculation is triggered by a fractional change of inside surface convection coefficient that exceeds AWTrigH.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.1	No	constant

4.1.4 TOP Weather Data Items

The following system variables (4.6.4) are determined from the weather file for each simulated hour:

$radBeam	beam irradiance on tracking surface (integral for hour, Btu/ft2).
$radDiff	diffuse irradiance on a horizontal surface (integral for hour, Btu/ft2).
$tDbO	dry bulb temp (oF).
$tWbO	wet bulb temp (oF).
$wO	humidity ratio
$windDirDeg	wind direction (degrees, NOT RADIANS; 0=N, 90=E).
$windSpeed	wind speed (mph).

The following are the terms determined from the weather file for internal use, and can be referenced with the probes shown.

    @Top.depressWbWet bulb depression (F).

    @Top.windSpeedSquaredWind speed squared (mph2).

wfName=string

Weather file path name for simulation. The file should be in the current directory, in the directory CSE.EXE was read from, or in a directory on the operating system PATH. Weather file formats supported are CSW, EPW, and ET1. Only full-year weather files are supported.

Note: Backslash (\) characters in path names must be doubled to work properly (e.g. “\\wthr\\mywthr.epw”). Forward slash (/) may be used in place of backslash without doubling.

Units	Legal Range	Default	Required	Variability
	file name,path optional	none	Yes	constant

skyModel=choice

Selects sky model used to determine relative amounts of direct and diffuse irradiance.

ISOTROPIC	traditional isotropic sky model
ANISOTROPIC	Hay anisotropic model

Units	Legal Range	Default	Required	Variability
	choices above	ANISOTROPIC	No	constant

skyModelLW=choice

Selects the model used to derive sky temperature used in long-wave (thermal) radiant heat exchange calculations for SURFACEs exposed to ambient conditions. See the RACM alorithms documentation for technical details.

Choice	Description
DEFAULT	Default: tSky from weather file if available else Berdahl-Martin
BERDAHLMARTIN	Berdahl-Martin (tSky depends on dew point, cloud cover, and hour)
DRYBULB	tSky = dry-bulb temperature (for testing)
BLAST	Blast model (tSky depends on dry-bulb)
IRHORIZ	Derives tSky from horizonal infrared data from the weather file (available on some EPW files only). Caution: minimal error checking! Missing weather file IR values are not handled correctly.

Units	Legal Range	Default	Required	Variability
	choices above	DEFAULT	No	constant

The reference temperature and humidity are used to calculate a humidity ratio assumed in air specific heat calculations. The small effect of changing humidity on the specific heat of air is generally ignored in the interests of speed, but the user can control the humidity whose specific heat is used through the refTemp and refRH inputs.

refTemp=float

Reference temperature (see above paragraph).

Units	Legal Range	Default	Required	Variability
oF	x \(\ge\) 0	60o	No	constant

refRH=float

Reference relative humidity (see above).

Units	Legal Range	Default	Required	Variability
	0 \(\leq\) x \(\leq\) 1	0.6	No	constant

grndRefl=float

Global ground reflectivity, used except where other value specified with sfGrndRefl or wnGrndRefl. This reflectivity is used in computing the reflected beam and diffuse radiation reaching the surface in question. It is also used to calculate the solar boundary conditions for the exterior grade surface in two-dimensional finite difference calculations for FOUNDATIONs.

Units	Legal Range	Default	Required	Variability
	0 \(\leq\) x \(\leq\) 1	0.2	No	Monthly-Hourly

The following values modify weather file data, permitting varying the simulation without making up special weather files. For example, to simulate without the effects of wind, use windF = 0; to halve the effects of diffuse solar radiation, use radDiffF = 0.5. Note that the default values for windSpeedMin and windF result in modification of weather file wind values unless other values are specified.

grndEmit=float

Long-wave emittance of the exterior grade surface used in two-dimensional finite difference calculations for FOUNDATIONs.

Units	Legal Range	Default	Required	Variability
	0.0 \(le\) x \(le\) 1.0	0.8	No	constant

grndRf

Ground surface roughness. Used for convection and wind speed corrections in two-dimensional finite difference calculations for FOUNDATIONs.

Units	Legal Range	Default	Required	Variability
ft	x \(\geq\) 0.0	0.1	No	constant

windSpeedMin=float

Minimum value for wind speed

Units	Legal Range	Default	Required	Variability
mph	x \(\ge\) 0	0.5	No	constant

windF=float

Wind Factor: multiplier for wind speeds read from weather file. windF is applied after windSpeedMin. Note that windF does not effect infiltration rates calculated by the Sherman-Grimsrud model (see e.g. ZONE.infELA). However, windF does modify AirNet flows (see IZXFER).

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	0.25	No	constant

terrainClass=int

Specifies characteristics of ground terrain in the project region.

1	ocean or other body of water with at least 5 km unrestricted expanse
2	flat terrain with some isolated obstacles (buildings or trees well separated)
3	rural areas with low buildings, trees, etc.
4	urban, industrial, or forest areas
5	center of large city

Units	Legal Range	Default	Required	Variability
	1 \(\leq\) x \(\leq\) 5	4	No	constant

radBeamF=float

Multiplier for direct normal (beam) irradiance

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	constant

radDiffF=float

Multiplier for diffuse horizonal irradiance.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	constant

hConvMod=choice

Enable/disable convection convective coefficient pressure modification factor.

\[0.24 + 0.76 \cdot P_{Location}/P_{SeaLevel}\]

Units	Legal Range	Default	Required	Variability
	YES, NO	YES	No	constant

soilDiff=float

Note: soilDiff is used as part of the simple ground model, which is no longer supported. Use soilCond, soilSpHt, and SoilDens instead.

Soil diffusivity, used in derivation of ground temperature. CSE calculates a ground temperature at 10 ft depth for each day of the year using dry-bulb temperatures from the weather file and soilDiff. Ground temperature is used in heat transfer calculations for SURFACEs with sfExCnd=GROUND. Note: derivation of mains water temperature for DHW calculations involves a ground temperature based on soil diffusivity = 0.025 and does not use this soilDiff.

Units	Legal Range	Default	Required	Variability
ft2/hr	x \(>\) 0	0.025	No	constant

soilCond=float

Soil conductivity. Used in two-dimensional finite difference calculations for FOUNDATIONs.

Units	Legal Range	Default	Required	**Variability
Btuh-ft/ft2-oF	x \(>\) 0	1.0	No	constant

soilSpHt=float

Soil specific heat. Used in two-dimensional finite difference calculations for FOUNDATIONs.

Units	Legal Range	Default	Required	Variability
Btu/lb-oF	x \(>\) 0	0.1	No	constant

soilDens=float

Soil density. Used in two-dimensional finite difference calculations for FOUNDATIONs.

Units	Legal Range	Default	Required	Variability
lb/ft3	x \(>\) 0	115	No	constant

farFieldWidth=float

Far-field width. Distance from foundation to the lateral, zero-flux boundary condition. Used in two-dimensional finite difference calculations for FOUNDATIONs.

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	130	No	constant

deepGrndCnd=choice

Deep-ground boundary condition type. Choices are WATERTABLE (i.e., a defined temperature) or ZEROFLUX.

Units	Legal Range	Default	Required	Variability
–	WATERTABLE, ZEROFLUX	ZEROFLUX	No	constant

deepGrndDepth=float

Deep-ground depth. Distance from exterior grade to the deep-ground boundary. Used in two-dimensional finite difference calculations for FOUNDATIONs.

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	130	No	constant

deepGrndT=float

Deep-ground temperature. Used when deepGrndCnd=WATERTABLE.

Units	Legal Range	Default	Required	Variability
F	x \(>\) 0	Annual average drybulb temperature	No	hourly

4.1.5 TOP TDV (Time Dependent Value) Items

CSE supports an optional comma-separated (CSV) text file that provides hourly TDV values for electricity and fuel. TDV values are read along with the weather file and the values merged with weather data. Several daily statistics are calculated for use via probes. The file has no other effect on the simulation. Only full-year TDV files are supported.

The format of a TDV file is the same as an IMPORTFILE with the proviso that the 4 line header is not optional and certain header items must have specified values. In the following table, non-italic items must be provided as shown (with optional quotes).

Line Contents Notes
1	TDV Data (TDV/Btu), runNumber, runNumber is not checked
2	timestamp optionally in quotes accessible via @TOP.TDVFileTimeStamp
3	title, hour title (in quotes if it contains commas) accessible via @TOP.TDVFileTitle
4	tdvElec, tdvFuel comma separated column names (optionally in quotes) not checked
5 ..	valElec,valFuel comma separated numerical values (8760 or 8784 rows) tdvElec is always in column 1, tdvFuel always in column 2 column names in row 4 do not determine order

Example TDV file –

    "TDV Data (TDV/Btu)","001"
    "Wed 14-Dec-16  12:30:29 pm"
    "BEMCmpMgr 2019.0.0 RV (758), CZ12, Fuel NatGas", Hour
    "tdvElec","tdvFuel"
    7.5638,2.2311
    7.4907,2.2311
    7.4478,2.2311
    7.4362,2.2311
    7.5255,2.2311
    7.5793,2.2311
    7.6151,2.2311
    7.6153,2.2311
    7.5516,2.2311
    (... continues for 8760 or 8784 data lines ...)

Note: additional columns can be included and are ignored.

The table below shows probes available for accessing TDV data in expressions. Except as noted, daily values are updated based on standard time, so they may be inaccurate by small amounts when daylight savings time is in effect.

Probe	Variability	Description
@Weather.tdvElec	Hour	current hour electricity TDV
@Weather.tdvFuel	Hour	current hour fuel TDV
@Weather.tdvElecPk	Day	current day peak electricity TDV (includes future hours). Updated at hour 23 during daylight savings.
@Weather.tdvElecAvg	Day	current day average electricity TDV (includes future hours)
@Weather.tdvElecPvPk	Day	previous day peak electricity TDV
@Weather.tdvElecAvg01	Day	previous day average electricity TDV
@weather.tdvElecHrRank	Day	hour ranking of TDVElec values. tdvElecHrRank[ 1] is the hour having the highest TDVElec, tdvElecHrRank[ 2] is the next highest, etc. The hour values are adjusted when dayight savings time is in effect, so they remain consistent with system variable $hour.
@weatherFile.tdvFileTimeStamp	Constant	TDV file timestamp (line 2 of header)
@weatherFile.tdvFileTitle	Constant	TDV file title (line 3 of header)
@Top.tdvFName	Constant	TDV file full path

TDVfName=string

Note: Backslash (\) characters in path names must be doubled to work properly (e.g. “\\data\\mytdv.tdv”). Forward slash (/) may be used in place of backslash without doubling.

Units	Legal Range	Default	Required	Variability
	file name, path optional	(no TDV file)	No	constant

4.1.6 TOP Report Data Items

These items are used in page-formatted report output files. See REPORTFILE, Section 5.245.21, and REPORT, Section 5.25.

repHdrL=string

Report left header. Appears at the upper left of each report page unless page formatting (rfPageFmt) is OFF. If combined length of repHdrL and repHdrR is too large for the page width, one or both will be truncated.

Units	Legal Range	Default	Required	Variability
		none	No	constant

repHdrR=string

Report right header. Appears at the upper right of each report page unless page formatting (rfPageFmt) is OFF. If combined length of repHdrL and repHdrR is too large for the page width, one or both will be truncated.

Units	Legal Range	Default	Required	Variability
		none	No	constant

repLPP=int

Total lines per page to be assumed for reports. Number of lines used for text (including headers and footers) is repLPP - repTopM - repBotM.

Units	Legal Range	Default	Required	Variability
lines	x \(\ge\) 50	66	No	constant

repTopM=int

Number of lines to be skipped at the top of each report page (prior to header).

Units	Legal Range	Default	Required	Variability
lines	0 \(\geq\) x \(\geq\) 12	3	No	constant

repBotM=int

Number of lines reserved at the bottom of each report page. repBotM determines the position of the footer on the page (blank lines after the footer are not actually written).

Units	Legal Range	Default	Required	Variability
lines	0 \(\geq\) x \(\geq\) 12	3	No	constant

repCPL=int

Characters per line for report headers and footers, user defined reports, and error messages. CSE writes simple ASCII files and assumes a fixed (not proportional) spaced printer font. Many of the built-in reports now (July 1992) assume a line width of 132 columns.

Units	Legal Range	Default	Required	Variability
characters	78 \(\leq\) x \(\leq\) 132	78	No	constant

repTestPfx=string

Report test prefix. Appears at beginning of report lines that are expected to differ from prior runs. This is useful for “hiding” lines from text comparison utilities in automated testing schemes. Note: the value specified with command line -x takes precedence over this input.

Units	Legal Range	Default	Required	Variability
		none	No	constant

4.1.7 TOP Autosizing

doAutoSize=choice

Controls invocation of autosizing phase prior to simulation.

Units	Legal Range	Default	Required	Variability
	YES, NO	NO, unless AUTOSIZE commands in input	No	constant

auszTol=float

Autosize tolerance. Sized capacity results are deemed final when successive design day calculations produce results within auszTol of the prior iteration.

Units	Legal Range	Default	Required	Variability
		.005	No	constant

heatDsTDbO=float

Heating outdoor dry bulb design temperature used for autosizing heating equipment.

Units	Legal Range	Default	Required	Variability
oF		none	No	hourly

heatDsTWbO=float

Heating outdoor design dry bulb temperature used for autosizing heating equipment.

Units	Legal Range	Default	Required	Variability
oF	x \(\ge\) 0	derived assuming RH=.7	No	hourly

CSE provides 3 mutually-exclusive methods for specifying cooling design conditions. Each resulting design day is simulated repeatedly until results (e.g. equipment capacities) converge to stable values. Multiple days are typically used to ensure the a range of temperatures and sun positions are considered.

• Design conditions. One or more DESCONDs are specified. DESCOND data is used to generate 24 hour design day weather data.
• Design days (from weather file). One or more dates are specified. Actual days from the weather file are simulated.
• Monthly design data. Deprecated method using conditions found in ET1 format weather files.

coolDsCond=list of up to 12 DESCONDs

Specifies cooling design conditions for cooling autosizing. A comma-separated list of up to 12 DESCOND names can be provided. Each day will be simulated repeatedly using weather conditions generated from DESCOND values.

Units	Legal Range	Default	Required	Variability
	name of DESCOND	none	No	constant

coolDsDay=list of up to 12 days

Specifies cooling design days for cooling autosizing. Each day will be simulated repeatedly using weather file conditions for that day.

Units	Legal Range	Default	Required	Variability
dates		none	No	constant

coolDsMo=list of up to 12 months

Deprecated method for specifying design days for cooling autosizing. Design conditions are taken from ET1 weather file header, however, the limited availale ET1 files do not contain design condition information.

Units	Legal Range	Default	Required	Variability
months		none	No	constant

4.1.8 TOP Debug Reporting

verbose=int

Controls verbosity of screen remarks. Most possible remarks are generated during autosizing of CNE models. Little or no effect in CSE models. TODO: document options

Units	Legal Range	Default	Required	Variability
	0 - 5	1	No	constant

The following dbgPrintMask values provide bitwise control of addition of semi-formated internal results to the run report file. The values and format of debugging reports are modified as required for testing purposes.

dbgPrintMaskC=int

Constant portion of debug reporting control.

Units	Legal Range	Default	Required	Variability
		0	No	constant

dbgPrintMask=int

Hourly portion of debug reporting control (generally an expression that evaluates to non-0 only on days or hours of interest).

Units	Legal Range	Default	Required	Variability
		0	No	hourly

dbgFlag=int

Allows passing an input value to ad-hoc debugging code. No permanent use; no impact on results.

Units	Legal Range	Default	Required	Variability
		0	No	subhourly

doCoverage=choice

Enables expression code coverage reporting. Development aid.

Units	Legal Range	Default	Required	Variability
	NO, YES	NO	No	constant

Related Probes:

• @top
• @weatherFile
• @weather
• @weatherNextHour

4.2 HOLIDAY

HOLIDAY objects define holidays. Holidays have no inherent effect, but input expressions can test for holidays via the $DOWH, $isHoliday, $isHoliTrue, $isWeHol, and $isBegWeek system variables (4.6.4).

Examples and the list of default holidays are given after the member descriptions.

hdName

Name of holiday: must follow the word HOLIDAY.

Units	Legal Range	Default	Required	Variability
	63 characters	none	Yes	constant

A holiday may be specified by date or via a rule such as “Fourth Thursday in November”. To specify by date, give hdDateTrue, and also hdDateObs or hdOnMonday if desired. To specify by rule, give all three of hdCase, hdMon, and hdDow.

hdDateTrue=date

The true date of a holiday, even if not celebrated on that day.

Units	Legal Range	Default	Required	Variability
	date	blank	No	constant

hdDateObs=date

The date that a holiday will be observed. Allowed only if hdDateTrue given and hdOnMonday not given.

Units	Legal Range	Default	Required	Variability
	date	hdDateTrue	No	constant

hdOnMonday=choice

If YES, holiday is observed on the following Monday if the true date falls on a weekend. Allowed only if hdDateTrue given and hdDateObs not given.

Note: there is no provision to celebrate a holiday that falls on a Saturday on Friday (as July 4 was celebrated in 1992).

Units	Legal Range	Default	Required	Variability
	YES/NO	YES	No	constant

hdCase=choice

Week of the month that the holiday is observed. hdCase, hdMon, and hdDow may be given only if hdDateTrue, hdDateObs, and hdOnMonday are not given.

Units	Legal Range	Default	Required	Variability
	FIRST SECOND THIRD FOURTH LAST	FIRST	No	constant

hdMon=choice

Month that the holiday is observed.

Units	Legal Range	Default	Required	Variability
	JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC	none	required if hdCase given	constant

hdDow=choice

Day of the week that the holiday is observed.

Units	Legal Range	Default	Required	Variability
	SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY	MONDAY	required if hdCase given	constant

endHoliday

Indicates the end of the holiday definition. Alternatively, the end of the holiday definition can be indicated by “END” or simply by beginning another object.

Units	Legal Range	Default	Required	Variability
			none	constant

Examples of valid HOLIDAY object specifications:

• Holiday on May first, observed date moved to following Monday if the first falls on a weekend (hdOnMonday defaults Yes).

    HOLIDAY MAYDAY;
        hdDateTrue = May 1;

• Holiday on May 1, observed on May 3.

    HOLIDAY MAYDAY;
        hdDateTrue = May 1;
        hdDateObs  = May 3;

• Holiday observed on May 1 even if on a weekend.

    HOLIDAY MAYDAY;
        hdDateTrue = May 1;
        hdOnMonday = No;

• Holiday observed on Wednesday of third week of March

    HOLIDAY HYPOTHET;
        hdCase = third;
        hdDow  = Wed;
        hdMon  = MAR

As with reports, Holidays are automatically generated for a standard set of Holidays. The following are the default holidays automatically defined by CSE:

New Year’s Day	*January 1
M L King Day	*January 15
President’s Day	3rd Monday in February
Memorial Day	last Monday in May
Fourth of July	*July 4
Labor Day	1st Monday in September
Columbus Day	2nd Monday in October
Veterans Day	*November 11
Thanksgiving	4th Thursday in November
Christmas	*December 25

* observed on the following Monday if falls on a weekend, except as otherwise noted:

If a particular default holiday is not desired, it can be removed with a DELETE statement:

    DELETE HOLIDAY Thanksgiving

    DELETE HOLIDAY "Columbus Day"  // Quotes necessary (due to space)

    DELETE HOLIDAY "VETERANS DAY"  // No case-sensitivity

Note that the name must be spelled exactly as listed above.

Related Probes:

• @holiday

4.3 DESCOND

Specifies conditions for a cooling design day. When referenced in TOP coolDsCond (see TOP Autosizing), DESCOND members are used to generate a 24 hour design day used during cooling autosizing. Note that coolDsCond can reference more than one DESCOND, allowing multiple design conditions to be used for autosizing. For example, both summer and fall days could be specified to ensure a range of sun angles are considered. Any DESCONDs that are not referenced in coolDsCond have no effect.

desCondName

Object name, given after “DESCOND”. Required for referencing from Top coolDsCond.

Units	Legal Range	Default	Required	Variability
	63 characters	none	Yes	constant

dcDay=date

Calendar date for this design cooling condition.

Units	Legal Range	Default	Required	Variability
	1-365	200	No	constant

dcDB=float

Design dry-bulb temperature (maxiumum temperature on design day).

Units	Legal Range	Default	Required	Variability
oF	no-limitations?	0.0	No	constant

dcMCDBR=float

Coincident daily dry-bulb range.

Units	Legal Range	Default	Required	Variability
oF	no-limitations?	none	No	constant

dcMCWB=float

Coincident wet-bulb design temperature.

Units	Legal Range	Default	Required	Variability
oF	no-limitations?	none	No	constant

dcMCWBR=float

Coincident daily wet-bulb range.

Units	Legal Range	Default	Required	Variability
oF	no-limitations?	none	No	constant

dcWindSpeed=float

Wind speed for design conditions.

Units	Legal Range	Default	Required	Variability
mph	x \(\geq\) 0	0.0	No	constant

DESCOND provides two mutually-exclusive methods for specifying design day direct beam and diffuse horizontal irradiance values. Both use the ASHRAE clear sky model. Consult the ASHRAE Handbook of Fundamentals Climatic Data chapter for model documentation.

• Pseudo optical depth. dcTauB and dcTauD define the taub and taud parameters in the clear sky model.
• Solar noon irradiance. CSE uses dcEbnSlrNoon and dcEdhSlrNoon to back-calculate taub and taud.

At most one of these methods can be used within a given DESCOND. If all solar-related values are omitted, the generated design day has 0 irradiance for all hours.

dcTauB=float
dcTauD=float

ASHRAE clear sky model beam and diffuse pseudo optical depths. These values are available by month for many locations in ASHRAE design weather data. Cannot be given if dcEbnSlrNoon and dcEdhSlrNoon are specified.

Units	Legal Range	Default	Required	Variability
		0 irradiance	No	constant

dcEbnSlrNoon=float
dcEdhSlrNoon=float

Solar noon direct beam and diffuse horizontal irradiance. Cannot be given if dcTauB and dcTauD are specified.

Units	Legal Range	Default	Required	Variability
Btuh/ft2	x \(\geq\) 0	0 irradiance	No	constant

endDesCond

Optionally indicates the end of the descond definition.

Units	Legal Range	Default	Required	Variability
		none	No

4.4 MATERIAL

MATERIAL constructs an object of class MATERIAL that represents a building material or component for later reference a from LAYER (see below). A MATERIAL so defined need not be referenced. MATERIAL properties are defined in a consistent set of units (all lengths in feet), which in some cases differs from units used in tabulated data. Note that the convective and air film resistances for the inside wall surface is defined within the SURFACE statements related to conductances.

matName

Name of material being defined; follows the word “MATERIAL”.

Units	Legal Range	Default	Required	Variability
	63 characters	none	Yes	constant

matThk=float

Thickness of material. If specified, matThk indicates the discreet thickness of a component as used in construction assemblies. If omitted, matThk indicates that the material can be used in any thickness; the thickness is then specified in each LAYER using the material (see below).

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	none	No	constant

matCond=float

Conductivity of material. Note that conductivity is always stated for a 1 foot thickness, even when matThk is specified; if the conductance is known for a specific thickness, an expression can be used to derive matCond.

Units	Legal Range	Default	Required	**Variability
Btuh-ft/ft2-oF	x \(>\) 0	none	Yes	constant

matCondT=float

Temperature at which matCond is rated. See matCondCT (next).

Units	Legal Range	Default	Required	Variability
oF	x \(>\) 0	70 oF	No	constant

matCondCT=float

Coefficient for temperature adjustment of matCond in the forward difference surface conduction model. Each hour (not subhour), the conductivity of layers using this material are adjusted as followslrCond = matCond * (1 + matCondCT*(T_layer – matCondT))

Units	Legal Range	Default	Required	Variability
oF-1		0	No	constant

Note: A typical value of matCondCT for fiberglass batt insulation is 0.00418 F^-1

matSpHt=float

Specific heat of material.

Units	Legal Range	Default	Required	Variability
Btu/lb-oF	x \(\ge\) 0	0 (thermally massless)	No	constant

matDens=float

Density of material.

Units	Legal Range	Default	Required	Variability
lb/ft3	x \(\ge\) 0	0 (massless)	No	constant

matRNom=float

Nominal R-value per foot of material. Appropriate for insulation materials only and used for documentation only. If specified, the current material is taken to have a nominal R-value that contributes to the reported nominal R-value for a construction. As with matCond, matRNom is always stated for a 1 foot thickness, even when matThk is specified; if the nominal R-value is known for a specific thickness, an expression can be used to derive matRNom.

Units	Legal Range	Default	Required	Variability
ft2-oF/Btuh	x \(>\) 0	none	No	constant

endMaterial

Optional to indicate the end of the material. Alternatively, the end of the material definition can be indicated by “END” or simply by beginning another object.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @material

4.5 CONSTRUCTION

CONSTRUCTION constructs an object of class CONSTRUCTION that represents a light weight or massive ceiling, wall, floor, or mass assembly (mass assemblies cannot, obviously, be lightweight). Once defined, CONSTRUCTIONs can be referenced from SURFACEs (below). A defined CONSTRUCTION need not be referenced. Each CONSTRUCTION is optionally followed by LAYERs, which define the constituent LAYERs of the construction.

conName

Name of construction. Required for reference from SURFACE and DOOR objects, below.

Units	Legal Range	Default	Required	Variability
	63 characters	none	Yes	constant

conU=float

U-value for the construction (NOT including surface (air film) conductances; see SURFACE statements). If omitted, one or more LAYERs must immediately follow to specify the LAYERs that make up the construction. If specified, no LAYERs can follow.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	calculated from LAYERs	if omitted, LAYERs must follow	constant

endConstruction

Optional to indicates the end of the CONSTRUCTION. Alternatively, the end of the CONSTRUCTION definition can be indicated by “END” or by beginning another object If END or endConstruction is used, it should follow the construction’s LAYER subobjects, if any.

Units	Legal Range	Default	Required	Variability
		N/A	No	constant

Related Probes:

• @construction

4.6 FOUNDATION

Foundation describes the two-dimensional relationship between ground-contact SURFACEs (i.e., sfExCnd = GROUND) and the surrounding ground. A FOUNDATION is referenced by Floor SURFACEs (see sfFnd). FOUNDATIONs are used to describe the two-dimensional features of foundation designs that cannot be captured by the typical one-dimensional constructions. Dimensions from the one-dimensional CONSTRUCTIONs associated with ground-contact floors and walls will automatically be interpreted into the two-dimensional context.

Any wall SURFACEs in contact with the ground must refer to a Floor SURFACE object (see sfFndFloor) to indicate which floor shares the same ground domain as a boundary condition (and establish the two-dimensional context for the basis of the ground calculations).

FOUNDATION objects are used to instantiate instances of heat transfer within Kiva.

MATERIALs used in a FOUNDATION cannot have variable properties at this time.

Most of the relevant dimensions and properties in the two-dimensional context are defined in the FOUNDATION object (and FNDBLOCK subobjects) with a few exceptions specified by specific SURFACEs:

• sfFnd
• sfFndFloor
• sfHeight
• sfExpPerim
• sfCon

Some properties applying to all FOUNDATIONs are defined at the TOP level:

• soilCond
• soilSpHt
• soilDens
• grndEmiss
• grndRefl
• grndRf
• farFieldWidth
• deepGrndCnd
• deepGrndDepth
• deepGrndT
• grndMinDim
• grndMaxGrthCoeff
• grndTimeStep

The following data members describe the dimensions and properties of the foundation wall. For below-grade walls, the CONSTRUCTION (and corresponding width) of the foundation wall is defined by the Wall SURFACEs referencing the FOUNDATION object. For on-grade floors, the CONSTRUCTION of the foundation wall must be defined using fdFtCon. The actual height of the foundation wall (from the top of the wall to the top of the slab) is defined by the corresponding SURFACE objects.

Other components of the foundation design (e.g., interior/exterior insulation) as well as other variations in thermal properties within the ground are defined using FNDBLOCK (foundation block) objects. Any number of FNDBLOCKs can appear after the definition of a FOUNDATION to be properly associated.

fdName

Name of foundation; give after the word FOUNDATION. Required for reference from SURFACE objects.

Units	Legal Range	Default	Required	Variability
–	63 characters	none	Yes	constant

fdWlHtAbvGrd=float

Wall height above grade.

Units	Legal Range	Default	Required	Variability
ft	x \(\geq\) 0	0.0	No	constant

fdWlDpBlwSlb=float

Wall depth below slab.

Units	Legal Range	Default	Required	Variability
ft	x \(\geq\) 0	0.0	No	constant

fdFtCon=conName

Name of CONSTRUCTION of the footing wall. Only required IF it is a slab foundation (i.e., no wall surfaces reference this FOUNDATION object).

Units	Legal Range	Default	Required	Variability
–	Name of a Construction	none	if a slab foundation	constant

endFoundation

Indicates the end of the foundation definition. Alternatively, the end of the foundation definition can be indicated by the declaration of another object or by END.

Units	Legal Range	Default	Required	Variability
		none	No	constant

4.7 FNDBLOCK

Foundation blocks are materials within the two-dimensional domain beyond those defined by the slab and wall SURFACEs. Each block is represented as a rectangle in the domain by specifying the X (lateral) and Z (vertical) coordinates of two opposite corners. The coordinate system for each point is relative to the X and Z references defined by the user. As a convention The positive X direction is away from the building, and the positive Z direction is down.

Options for X and Z references are illustrated in the figure below.

The default reference is WALLINT, WALLTOP.

An example of defining a block for interior wall insulation is shown below. Here the two points defining the block (P1 and P2) are both shown relative to their reference points (Ref1 and Ref2, respectively).

Note: X and Z point values of zero imply that a point is the same as the reference point. The default for X and Z point values is zero since points will often align with one or both of the reference values.

It does not matter which of the four corners of a block are used to define the two points as long as they are opposite corners.

fbMat=matName

Name of MATERIAL of the foundation block.

Units	Legal Range	Default	Required	Variability
–	Name of a Material	none	Yes	constant

fbX1Ref=choice

Relative X origin for fbX1 point. Options are:

• SYMMETRY
• WALLINT
• WALLCENTER
• WALLEXT
• FARFIELD

Units	Legal Range	Default	Required	Variability
	choices above	WALLINT	No	constant

fbZ1Ref=choice

Relative Z origin for fbZ1 point. Options are:

• WALLTOP
• GRADE
• SLABTOP
• SLABBOTTOM
• WALLBOTTOM
• DEEPGROUND

Units	Legal Range	Default	Required	Variability
	choices above	WALLTOP	No	constant

fbX1=float

The X position of the first corner of the block relative to fbX1Ref.

Units	Legal Range	Default	Required	Variability
ft		0.0	No	constant

fbZ1=float

The Z position of the first corner of the block relative to fbZ1Ref.

Units	Legal Range	Default	Required	Variability
ft		0.0	No	constant

fbX2Ref=choice

Relative X origin for fbX2 point. Options are:

• SYMMETRY
• WALLINT
• WALLCENTER
• WALLEXT
• FARFIELD

Units	Legal Range	Default	Required	Variability
	choices above	WALLINT	No	constant

fbZ2Ref=choice

Relative Z origin for fbZ2 point. Options are:

• WALLTOP
• GRADE
• SLABTOP
• SLABBOTTOM
• WALLBOTTOM
• DEEPGROUND

Units	Legal Range	Default	Required	Variability
	choices above	WALLTOP	No	constant

fbX2=float

The X position of the second corner of the block relative to fbX2Ref.

Units	Legal Range	Default	Required	Variability
ft		0.0	No	constant

fbZ2=float

The Z position of the second corner of the block relative to fbZ2Ref.

Units	Legal Range	Default	Required	Variability
ft		0.0	No	constant

endFndBlock

Indicates the end of the foundation block definition. Alternatively, the end of the foundation block definition can be indicated by the declaration of another object or by END.

Units	Legal Range	Default	Required	Variability
		none	No	constant

4.8 LAYER

LAYER constructs a subobject of class LAYER belonging to the current CONSTRUCTION. LAYER is not recognized except immediately following CONSTRUCTION or another LAYER. The members represent one layer (that optionally includes framing) within the CONSTRUCTION.

The layers should be specified in inside to outside order. A framed layer (lrFrmMat and lrFrmFrac given) is modeled by creating a homogenized material with weighted combined conductivity and volumetric heat capacity. Caution: it is generally preferable to model framed constructions using two separate surfaces (one with framing, one without). At most one framed layer (lrFrmMat and lrFrmFrac given) is allowed per construction.

The layer thickness may be given by lrThk, or matThk of the material, or matThk of the framing material if any. The thickness must be specified at least one of these three places; if specified in more than one place and not consistent, an error message occurs.

lrName

Name of layer (follows “LAYER”). Required only if the LAYER is later referenced in another object, for example with LIKE or ALTER; however, we suggest naming all objects for clearer error messages and future flexibility.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

lrMat=matName

Name of primary MATERIAL in layer.

Units	Legal Range	Default	Required	Variability
	name of a MATERIAL	none	Yes	constant

lrThk=float

Thickness of layer.

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	Required if matThk not specified in referenced lrMat	No	constant

lrFrmMat=matName

Name of framing MATERIAL in layer, if any. At most one layer with lrFrmMat is allowed per CONSTRUCTION. See caution above regarding framed-layer model.

Units	Legal Range	Default	Required	Variability
	name of a MATERIAL	no framed layer	No	constant

lrFrmFrac=float

Fraction of layer that is framing. Must be specified if frmMat is specified. See caution above regarding framed-layer model.

Units	Legal Range	Default	Required	Variability
	0 \(\leq\) x \(\leq\) 1	no framed layer	Required if lrFrmMat specified, else disallowed	constant

endLayer

Optional end-of-LAYER indicator; LAYER definition may also be indicated by “END” or just starting the definition of another LAYER or other object.

Related Probes:

• @layer

4.9 GLAZETYPE

GLAZETYPE constructs an object of class GLAZETYPE that represents a glazing type for use in WINDOWs.

gtName

Name of glazetype. Required for reference from WINDOW objects, below.

Units	Legal Range	Default	Required	Variability
	63 characters	none	Yes	constant

gtModel=choice

Selects model to be used for WINDOWs based on this GLAZETYPE.

Units	Legal Range	Default	Required	Variability
	SHGC, ASHWAT	SHGC	No	constant

gtU=float

Glazing conductance (U-factor without surface films, therefore not actually a U-factor but a C-factor). Used as wnU default; an error message will be issued if the U value is not given in the window (wnU) nor in the glazeType (gtU). Preferred Approach: To use accurately with standard winter rated U-factor from ASHRAE or NFRC enter as:

    gtU = (1/((1/U-factor)-0.85)

Where 0.85 is the sum of the interior (0.68) and exterior (0.17) design air film resistances assumed for rating window U-factors. Enter wnInH (usually 1.5=1/0.68) instead of letting it default. Enter the wnExH or let it default. It is important to use this approach if the input includes gnFrad for any gain term. Using approach 2 below will result in an inappropriate internal gain split at the window.

Approach 2. Enter gtU=U-factor and let the wnInH and wnExH default. This approach systematically underestimates the window U-factor because it adds the wnExfilm resistance to 1/U-factor thereby double counting the exterior film resistance. This approach will also yield incorrect results for gnFrad internal gain since the high wnInH will put almost all the gain back in the space.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	none	No	constant

gtUNFRC=float

Fenestration system (including frame) U-factor evaluated at NFRC heating conditions. For ASHWAT windows, a value for the NFRC U-factor is required, set via gtUNFRC or wnUNFRC.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	none	No	constant

gtSHGC=float

Glazing Solar Heat Gain Coefficient: fraction of normal beam insolation which gets through glass to space inside. We recommend using this to represent the glass normal transmissivity characteristic only, before shading and framing effects

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	none	Yes	constant

gtSMSO=float

SHGC multiplier with shades open. May be overriden in the specific window input.

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	1.0	No	Monthly - Hourly

gtSMSC=float

SHGC multiplier with shades closed. May be overriden in the specific window input.

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	gtSMSO (no shades)	No	Monthly - Hourly

gtFMult=float

Framing multiplier used if none given in window, for example .9 if frame and mullions reduce the solar gain by 10%. Default of 1.0 implies frame/mullion effects allowed for in gtSHGC’s or always specified in Windows.

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	gtSHGCO	No	Monthly - Hourly

gtPySHGC =float

Four float values separated by commas. Coefficients for incidence angle SHGC multiplier polynomial applied to gtSHGC to determine beam transmissivity at angles of incidence other than 90 degrees. The values are coefficients for first through fourth powers of the cosine of the incidence angle; there is no constant part. An error message will be issued if the coefficients do not add to one. They are used in the following computation:

    angle = incidence angle of beam radiation, measured from normal to glass.

    cosI = cos( angle)

    angMult = a*cosI + b*cosI^2 + c*cosI^3 + d*cosI^4

    beamXmisvty = gtSHGCO * angMult (shades open)

Units	Legal Range	Default	Required	Variability
float	any	none	Yes	constant

gtDMSHGC=float

SHGC diffuse multiplier, applied to gtSHGC to determine transmissivity for diffuse radiation.

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	none	Yes	constant

gtDMRBSol=float

SHGC diffuse multiplier, applied to qtSHGC to determine transmissivity for diffuse radiation reflected back out the window. Misnamed as a reflectance. Assume equal to DMSHGC if no other data available.

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	none	Yes	constant

gtNGlz=int

Number of glazings in the Glazetype (bare glass only, not including any interior or exterior shades).

Units	Legal Range	Default	Required	Variability
	0 \(<\) x \(\leq\) 4	2	No	constant

gtExShd=choice

Exterior shading type (ASHWAT only).

Units	Legal Range	Default	Required	Variability
	NONE INSCRN	NONE	No	constant

gtInShd=choice

Interior shade type (ASHWAT only).

Units	Legal Range	Default	Required	Variability
	NONE DRAPEMED	NONE	No	constant

gtDirtLoss=float

Glazing dirt loss factor.

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	0	No	constant

endGlazeType

Optional to indicates the end of the Glazetype. Alternatively, the end of the GLAZETYPE definition can be indicated by “END” or by beginning another object

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @glazeType

4.10 METER

A METER object is a user-defined “device” that records energy consumption of equipment as simulated by CSE. The user defines METERs with the desired names, then assigns energy uses of specific equipment to the desired meters using commands described under each equipment type’s class description (AIRHANDLER, TERMINAL, etc.). Additional energy use from equipment not simulated by CSE (except optionally for its effect on heating and cooling loads) can also be charged to METERs (see GAIN). The data accumulated by meters can be reported at hourly, daily, monthly, and annual (run) intervals by using REPORTs and EXPORTs of type MTR.

Meters account for energy use in the following pre-defined categories, called end uses. The abbreviations in parentheses are used in MTR report headings (and for gnMeter input, below). You also get a column for the net total on the meter (abbreviated “Tot”).

Clg	Cooling
Htg	Heating (includes heat pump compressor)
HPBU	Heat pump resistance heating (backup and defrost)
DHW	Domestic (service) hot water
DHWBU	Domestic (service) hot water heating backup (HPWH resistance)
DHWMFL	Domestic (service) hot water heating multi-family loop pumping and loss makeup
FANC	Fans, AC and cooling ventilation
FANH	Fans, heating
FANV	Fans, IAQ venting
FAN	Fans, other purposes
AUX	HVAC auxiliaries such as pumps
PROC	Process
LIT	Lighting
RCP	Receptacles
EXT	Exterior lighting
REFR	Refrigeration
DISH	Dishwashing
DRY	Clothes drying
WASH	Clothes washing
COOK	Cooking
USER1	User-defined category 1
USER2	User-defined category 2
BT	Battery charge power
PV	Photovoltaic power generation

The user has complete freedom over how many meters are defined and how equipment is assigned to them. At one extreme, a single meter “Electricity” could be defined and have all of electrical uses assigned to it. On the other hand, definition of separate meters “Elect_Fan1”, “Elect_Fan2”, and so forth allows accounting of the electricity use for individual pieces of equipment. Various groupings are possible: for example, in a building with several air handlers, one could separate the energy consumption of the fans from the coils, or one could separate the energy use by air handler, or both ways, depending on the information desired from the run.

The members that assign energy use to meters include:

• GAIN: gnMeter, gnEndUse
• ZONE: xfanMtr
• IZXFER: izfanMtr
• RSYS: rsElecMtr, rsFuelMtr
• DHWSYS: wsElecMtr, wsFuelMtr
• DHWHEATER: whElectMtr, whFuelMtr
• DHWPUMP: wpElecMtr
• DHWLOOPPUMP: wlpElecMtr
• PVARRAY: pvElecMeter
• TERMINAL: tuhcMtr, tfanMtr
• AIRHANDLER: sfanMtr, rfanMtr, ahhcMtr, ahccMtr, ahhcAuxOnMtr, ahhcAuxOffMtr, ahhcAuxFullOnMtr, ahhcAuxOnAtAllMtr, ahccAuxOnMtr, ahccAuxOffMtr, ahccAuxFullOnMtr, ahccAuxOnAtAllMtr
• BOILER: blrMtr, blrpMtr, blrAuxOnMtr, blrAuxOffMtr, blrAuxFullOnMtr, blrAuxOnAtAllMtr
• CHILLER: chMtr, chppMtr, chcpMtr, chAuxOnMtr, chAuxOffMtr, chAuxFullOnMtr, chAuxOnAtAllMtr
• TOWERPLANT: tpMtr

The end use can be specified by the user only for GAINs and PVARRAYs; in other cases it is hard-wired to Clg, Htg, FanC, FanH, FanV, Fan, or Aux as appropriate.

mtrName

Name of meter: required for assigning energy uses to the meter elsewhere.

Units	Legal Range	Default	Required	Variability
	63 characters	none	Yes	constant

mtrDemandRate=float

DmdCost per Btu of demand, for a month.

Units	Legal Range	Default	Required	Variability
		N/A	No	constant

mtrRate=float

Cost of energy use per Btu.

Units	Legal Range	Default	Required	Variability
		N/A	No	constant

mtrSubmeters=list of up to 50 METERs

A comma-separate list of METERs that are accumulated into this METER with optional multipliers (see mtrSubmeterMults). Submeters facilitate flexible categorization of energy results. In addition, use of mtrSubmeterMults allows energy results from a representative model to be scaled and included in overall results. For example, a typical zone could be used to represent 5 similar spaces. The energy uses of the typical zone could be assigned to a dedicated METER that is accumulated to a main METER with a multiplier of 5. Rules –

• A METER cannot reference itself as a submeter.
• A given METER can be referenced only once in the mtrSubmeters list.
• Circular references are not allowed.

Units	Legal Range	Default	Required	Variability
	names of METERs		No	constant

mtrSubmeterMults=list of up to 50 floats

Submeter multipliers. Use cases for multipliers include –

• Scaling results from portions of a model to approximate the behavior of multiple similar aspects (e.g. multiple floors in a high-rise building)
• Tracking energy use during selected time intervals; for example, peak-period energy use could be metered for certain hours via scheduled multipliers of 0 or 1.

A note re default values: if mtrSubmeterMults is omitted, all multipliers are defaulted to 1. However, when mtrSubmeterMults is included, a multiplier value should be provided for each METER listed in mtrSubmeters since unspecified values are set to 0.

Units	Legal Range	Default	Required	Variability
		1	No	hourly

endMeter

Indicates the end of the meter definition. Alternatively, the end of the meter definition can be indicated by the declaration of another object or by END.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @meter

4.11 DHWMETER

A DHWMETER object is a user-defined “device” that records water consumption as simulated by CSE. The data accumulated by DHWMETERs can be reported at hourly, daily, monthly, and annual (run) intervals by using REPORTs and EXPORTs of type DHWMTR. Water use is reported in gallons.

DHWMETERs account for water use in the following pre-defined end uses. The abbreviations in parentheses are used in DHWMTR report headings.

• Total water use (Total)
• Unknown end use (Unknown)
• Miscellaneous draws (Faucet)
• Shower (Shower)
• Bathtub (Bath)
• Clothes washer (CWashr)
• Dishwasher (DWashr)

DHWSYS items wsWHhwMtr and wsFXhwMtr specify the DHWMETER(s) to which water consumption is accumulated.

dhwMtrName

Name of meter: required for assigning water uses to the DHWMETER.

Units	Legal Range	Default	Required	Variability
	63 characters	none	Yes	constant

endDhwMeter

Related Probes:

• @DHWmeter

4.12 AFMETER

An AFMETER object is a user-defined “device” that records zone air flows as simulated by CSE. The user defines AFMETERs and assigns them to zones (see ZONE znAFMtr).

Air flow is recorded in standard air cfm (density 0.075 lb/ft3) at subhour, hour, day, month, and year intervals. At intervals of an hour and longer, values are averaged. Flows are categorized according to IZXFER izAFCat.

If any AFMETERs are defined, an additional AFMETER “sum_of_AFMETERs” is automatically created where the sums of all user-define AFMETERs are accumulated.

Note that only AirNet flows are recorded.

AFMETER results can be REPORTed using rpType=AFMTR (or EXPORTed using exType=AFMTR). See Air Flow Meter Report.

afMtrName

Name of meter: required for assigning air flows to the AFMETER.

Units	Legal Range	Default	Required	Variability
	63 characters	none	Yes	constant

endAFMeter

Indicates the end of the meter definition. Alternatively, the end of the meter definition can be indicated by the declaration of another object or by END.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @afmeter

4.13 LOADMETER

A LOADMETER object is a user-defined “device” that records heating and cooling loads as computed by CSE. The user defines LOADMETERs and assigns them to ZONEs and/or RSYSs (see ZONE znLoadMtr and RSYS rsLoadMtr).

Loads are accumulated for subhour, hour, day, month, and annual intervals. All values are in Btu. Values >0 indicated heat into the process or zone – thus heating loads are >0 and cooling loads are <0.

LOADMETER results must be reported using user-defined REPORTs or EXPORTs. For example –

REPORT rpType=UDT rpFreq=Month rpDayBeg=Jan 1 rpDayEnd=Dec 31
    REPORTCOL colHead="mon" colVal=$Month colWid=3
    REPORTCOL colHead="Heating" colVal=@LoadMeter[ 1].M.qHtg colDec=0 colWid=10
    REPORTCOL colHead="Cooling" colVal=@LoadMeter[ 1].M.qClg colDec=0 colWid=10

ldMtrName

Name of LOADMETER: required for assigning to ZONEs and RSYSs.

Units	Legal Range	Default	Required	Variability
	63 characters	none	Yes	constant

lmtSubmeters=list of up to 50 LOADMETERs

A comma-separate list of LOADMETERs that are accumulated into this LOADMETER with optional multipliers (see lmtSubmeterMults). Submeters facilitate flexible categorization of loads results. In addition, use of lmtSubmeterMults allows load results from a representative model to be scaled and included in overall results. For example, a typical zone could be used to represent 5 similar spaces. The loads calculated for the typical zone could be assigned to a dedicated LOADMETER and that LOADMETER accumulated to a main LOADMETER with a multiplier of 5. Rules –

• A LOADMETER cannot reference itself as a submeter.
• A given LOADMETER can be referenced only once in the lmtSubmeters list.
• Circular references are not allowed.

Units	Legal Range	Default	Required	Variability
	names of LOADMETERs		No	constant

lmtSubmeterMults=list of up to 50 floats

Submeter multipliers.

A note re default values: if lmtSubmeterMults is omitted, all multipliers are defaulted to 1. However, when lmtSubmeterMults is included, a multiplier value should be provided for each LOADMETER listed in lmtSubmeters since unspecified values are set to 0.

Units	Legal Range	Default	Required	Variability
		1	No	subhourly

endLOADMETER

Indicates the end of the meter definition. Alternatively, the end of the meter definition can be indicated by the declaration of another object or by END.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @loadmeter

4.14 ZONE

ZONE constructs an object of class ZONE, which describes an area of the building to be modeled as having a uniform condition. ZONEs are large, complex objects and can have many subobjects that describe associated surfaces, shading devices, HVAC equipment, etc.

4.14.1 ZONE General Members

znName

Name of zone. Enter after the word ZONE; no “=” is used.

Units	Legal Range	Default	Required	Variability
	63 characters	none	Yes	constant

znModel=choice

Selects model for zone.

CNE	Older central difference model based on original CALPAS methods. Not fully supported and not suitable for current compliance applications.
CZM	Conditioned zone model. Forward-difference, short time step methods are used.
UZM	Unconditioned zone model. Identical to CZM except heating and cooling are not supported. Typically used for attics, garages, and other ancillary spaces.

Units	Legal Range	Default	Required	Variability
	choices above	CNE	No	constant

znArea=float

Nominal zone floor area.

Units	Legal Range	Default	Required	Variability
ft2	x \(>\) 0	none	Yes	constant

znVol=float

Nominal zone volume.

Units	Legal Range	Default	Required	Variability
ft3	x \(>\) 0	none	Yes	constant

znAzm=float

Zone azimuth with respect to bldgAzm. All surface azimuths are relative to znAzm, so that the zone can be rotated by changing this member only. Values outside the range 0^o to 360^o are normalized to that range.

Units	Legal Range	Default	Required	Variability
degrees	unrestricted	0	No	constant

znFloorZ=float

Nominal zone floor height relative to arbitrary 0 level. Used re determination of vent heights

Units	Legal Range	Default	Required	Variability
ft	unrestricted	0	No	constant

znCeilingHt=float

Nominal zone ceiling height relative to zone floor (typically 8 – 10 ft).

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	znVol / znArea	No	constant

znEaveZ=float

Nominal eave height above ground level. Used re calculation of local surface wind speed. This in turn influences outside convection coefficients in some surface models and wind-driven air leakage.

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	znFloorZ + infStories8*	No	constant

znCAir=float

Zone “air” heat capacity: represents heat capacity of air, furniture, “light” walls, and everything in zone except surfaces having heat capacity (that is, non-QUICK surfaces).

Units	Legal Range	Default	Required	Variability
Btu/oF	x \(\geq\) 0	3.5 znArea*	No	constant

znHcAirX=float

Zone air exchange rate used in determination of interior surface convective coefficients. This item is generally used only for model testing.

Units	Legal Range	Default	Required	Variability
ACH	x \(>\) 0	as modeled	No	subhourly

znHcFrcF=float

Zone surface forced convection factor. Interior surface convective transfer is modeled as a combination of forced and natural convection. hcFrc = znHcFrcF * znHcAirX^.8. See CSE Engineering Documentation.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	.2	.2	No	hourly

znHIRatio=float

Zone hygric inertia ratio. In zone moisture balance calculations, the effective dry-air mass = znHIRatio * (zone dry air mass). This enhancement can be used to represente the moisture storage capacity of zone surfaces and contents.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

znSC=float

Zone shade closure. Determines insolation through windows (see WINDOW members wnSCSO and wnSCSC) and solar gain distribution: see SGDIST members sgFSO and sgFSC. 0 represents shades open; 1 represents shades closed; intermediate values are allowed. An hourly variable CSE expression may be used to schedule shade closure as a function of weather, time of year, previous interval HVAC use or zone temperature, etc.

Units	Legal Range	Default	Required	Variability
	0 \(\leq\) x \(\leq\) 1	1 when cooling was used in previous hour, else 0	No	hourly

znTH=float

Heating set point used (and required) when znModel=CZM and zone has no terminals.

Units	Legal Range	Default	Required	Variability
oF	0 < znTH < znTC	none	Per above	subhourly

znTD=float

Desired set point (temperature maintained with ventilation if possible) for znModel=CZM. Must be specified when zone ventilation is active.

Units	Legal Range	Default	Required	Variability
oF	x > 0; znTH < znTD < znTC	none	if venting	subhourly

znTC=float

Cooling set point used (and required) when znModel=CZM and zone has no terminals.

Units	Legal Range	Default	Required	Variability
oF	0 < znTC > znTH	none	Per above	subhourly

znModel = CZM zone heating and cooling is provided either via an RSYS HVAC system, by “magic” heat transfers specified by znQxxx items, or via TERMINAL (s). One of these must be defined.

znRSys=rsysName

Name of RSYS providing heating, cooling, and optional central fan integrated ventilation to this zone.

Units	Legal Range	Default	Required	Variability
	RSYS name	(no RSYS)	No	constant

znQMxH=float

Heating capacity at current conditions

Units	Legal Range	Default	Required	Variability
Btuh	x \(\geq\) 0	none	No	hourly

znQMxHRated=float

Rated heating capacity

Units	Legal Range	Default	Required	Variability
Btuh	x \(\geq\) 0	none	No	constant

znQMxC=float

Cooling capacity at current conditions

Units	Legal Range	Default	Required	Variability
Btuh	x \(\leq\) 0	none	No	hourly

znQMxCRated=float

Rated cooling capacity

Units	Legal Range	Default	Required	Variability
Btuh	x \(\leq\) 0	none	No	constant

4.14.2 ZONE Infiltration

The following control a simplified air change plus leakage area model. The Sherman-Grimsrud model is used to derive air flow rate from leakage area and this rate is added to the air changes specified with infAC. Note that TOP.windF does not modify calculated infiltration rates, since the Sherman-Grimsrud model uses its own modifiers. See also AirNet models available via IZXFER.

infAC=float

Zone infiltration air changes per hour.

Units	Legal Range	Default	Required	Variability
1/hr	x \(\geq\) 0	0.5	No	hourly

infELA=float

Zone effective leakage area (ELA).

Units	Legal Range	Default	Required	Variability
in2	x \(\geq\) 0	0.0	No	hourly

infShld=int

Zone local shielding class, used in derivation of local wind speed for ELA infiltration model, wind-driven AirNet leakage, and exterior surface coefficients. infShld values are –

1	no obstructions or local shielding
2	light local shielding with few obstructions
3	moderate local shielding, some obstructions within two house heights
4	heavy shielding, obstructions around most of the perimeter
5	very heavy shielding, large obstructions surrounding the perimeter within two house heights

Units	Legal Range	Default	Required	Variability
	1 \(\leq\) x \(\leq\) 5	3	No	constant

infStories=int

Number of stories in zone, used in ELA model.

Units	Legal Range	Default	Required	Variability
	1 \(\leq\) x \(\leq\) 3	1	No	constant

znWindFLkg=float

Wind speed modifier factor. The weather file wind speed is multiplied by this factor to yield a local wind speed for use in infiltration and convection models.

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 0	derived from znEaveZ and infShld	No	constant

znAFMtr=afMtrName

Name of an AFMETER object, if any, to which zone AirNet air flows are recorded. ZnAFMtr defines a pressure boundary for accounting purposes. Multiple zones having the same AFMETER are treated as a single volume – interzone flows within that volume are not recorded. For example, to obtain “building total” flow data, a common AFMETER could be assigned to several conditioned zones but not to adjacent unconditioned zones such as attic spaces.

Units	Legal Range	Default	Required	Variability
	name of an AFMETER	not recorded	No	constant

znLoadMtr=ldMtrName

Name of a LOADMETER object, if any, to which zone heating and cooling loads are recorded.

Units	Legal Range	Default	Required	Variability
	name of a LOADMETER	not recorded	No	constant

4.14.3 ZONE Exhaust Fan

Presence of an exhaust fan in a zone is indicated by specifying a non-zero design flow value (xfanVfDs).

Zone exhaust fan model implementation is incomplete as of July, 2011. The current code calculates energy use but does not account for the effects of air transfer on room heat balance. IZXFER provides a more complete implementation.

xfanFOn=float

Exhaust fan on fraction. On/off control assumed, so electricity requirement is proportional to run time.

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	1	No	hourly

Example: The following would run an exhaust fan 70% of the time between 8 AM and 5 PM:

    xfanFOn = select( (\$hour >= 7 && \$hour < 5), .7,
                                          default, 0 );

xfanVfDs=float

Exhaust fan design flow; 0 or not given indicates no fan.

Units	Legal Range	Default	Required	Variability
cfm	x \(\geq\) 0	0, no fan	If fan present	constant

xfanPress=float

Exhaust fan external static pressure.

Units	Legal Range	Default	Required	Variability
inches	0.05 \(\leq\) x \(\leq\) 1.0	0.3	No	constant

Only one of xfanElecPwr, xfanEff, and xfanShaftBhp may be given: together with xfanVfDs and xfanPress, any one is sufficient for CSE to detemine the others and to compute the fan heat contribution to the air stream.

xfanElecPwr=float

Fan input power per unit air flow (at design flow and pressure).

Units	Legal Range	Default	Required	Variability
W/cfm	x \(>\) 0	derived from xfanEff	If xfanEff and xfanShaftBhp not present	constant

xfanEff=float

Exhaust fan/motor/drive combined efficiency.

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	0.08	No	constant

xfanShaftBhp=float

Fan shaft power at design flow and pressure.

Units	Legal Range	Default	Required	Variability
BHP	x \(>\) 0	derived from xfanElecPwr and xfanVfDs	If xfanElecPwr not present	constant

xfanMtr=mtrName

Name of METER object, if any, by which fan’s energy use is recorded (under end use category “fan”).

Units	Legal Range	Default	Required	Variability
	name of a METER	not recorded	No	constant

endZone

Indicates the end of the zone definition. Alternatively, the end of the zone definition can be indicated by the declaration of another object or by “END”. If END or endZone is used, it should follow the definitions of the ZONE’s subobjects such as GAINs, SURFACEs, TERMINALs, etc.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @zone
• @znRes (accumulated results)

4.15 GAIN

A GAIN object adds sensible and/or latent heat to the ZONE, and/or adds arbitrary energy use to a METER. GAINs may be subobjects of ZONEs and are normally given within the input for their ZONE. As many GAINs as desired (or none) may be given for each ZONE. Alternatively, GAINs may be subobjects of TOP and specify gnZone to specify their associate zone.

Each gain has an amount of power (gnPower), which may optionally be accumulated to a METER (gnMeter). The power may be distributed to the zone, plenum, or return as sensible heat with an optional fraction radiant, or to the zone as latent heat (moisture addition), or not.

4.15.1 Gain zones

The gain to the zone may be further divided into convective sensible, radiant sensible and latent heat via the gnFrRad and gnFrLat members; the plenum and return gains are assumed all convective sensible.

In the CNE zone mode, the radiant internal gain is distributed to the surfaces in the zone, rather than going directly to the zone “air” heat capacity (znCAir). A simple model is used – all surfaces are assumed to be opaque and to have the same (infrared) absorptivity – even windows. Along with the assumption that the zone is spherical (implicit in the current treatment of solar gains), this allows distribution of gains to surfaces in proportion to their area, without any absorptivity or transmissivity calculations. The gain for windows and quick-model surfaces is assigned to the znCAir, except for the portion which conducts through the surface to the other side rather than through the surface film to the adjacent zone air; the gain to massive (delayed-model) surfaces is assigned to the side of surface in the zone with the gain.

Radiant internal gains are included in the IgnS (Sensible Internal Gain) column in the zone energy balance reports. (They could easily be shown in a separate IgnR column if desired.) Any energy transfer shows two places in the ZEB report, with opposite signs, so that the result is zero – otherwise it wouldn’t be an energy balance. The rest of the reporting story for radiant internal gains turns out to be complex. The specified value of the radiant gain (gnPower * gnFrZn * gnFrRad) shows in the IgnS column. To the extent that the gain heats the zone, it also shows negatively in the Masses column, because the zone CAir is lumped with the other masses. To the extent that the gain heats massive surfaces, it also shows negatively in the masses column. To the extent that the gain conducts through windows and quick-model surfaces, it shows negatively in the Conduction column. If the gain conducts through a quick-model surface to another zone, it shows negatively in the Izone (Interzone) column, positively in the Izone column of the receiving zone, and negatively in the receiving zone’s Masses or Cond column.

gnName

Name of gain; follows the word GAIN if given.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

gnZone=znName

Name of ZONE to which heat gains are added. Omitted when GAIN is given as a ZONE subobject. If a TOP subobject (i.e., not a ZONE subobject) and znZone is omitted, heat gains are discarded but energy use is still recorded to gnMeter. This feature can be used to represent energy uses that our outside of conditioned zones (e.g. exterior lighting).

Units	Legal Range	Default	Required	Variability
	name of ZONE	parent zone if any	No	constant

gnPower=float

Rate of heat addition/energy use. Negative gnPower values may be used to represent heat removal/energy generation. Expressions containing functions are commonly used with this member to schedule the gain power on a daily and/or hourly basis. Refer to the functions section in Section 4 for details and examples.

All gains, including electrical, are specified in Btuh units unless associated with DHW use (see gnCtrlDHWSYS), in which case gnPower is specified in Btuh/gal. Note that meter reporting of internal gain is in MBtu (millions of Btu) by default.

Units	Legal Range	Default	Required	Variability
Btuh	no restrictions	none	Yes	hourly

gnMeter=choice

Name of meter by which this GAIN’s gnPower is recorded. If omitted, gain is assigned to no meter and energy use is not accounted in CSE simulation reports; thus, gnMeter should only be omitted for “free” energy sources.

Units	Legal Range	Default	Required	Variability
	name of METER	none	No	constant

gnEndUse=choice

Meter end use to which the GAIN’s energy use should be accumulated.

Clg	Cooling
Htg	Heating (includes heat pump compressor)
HPBU	Heat pump resistance heating (backup and defrost)
DHW	Domestic (service) hot water
DHWBU	Domestic (service) hot water heating backup (HPWH resistance)
DHWMFL	Domestic (service) hot water heating multi-family loop pumping and loss makeup
FANC	Fans, AC and cooling ventilation
FANH	Fans, heating
FANV	Fans, IAQ venting
FAN	Fans, other purposes
AUX	HVAC auxiliaries such as pumps
PROC	Process
LIT	Lighting
RCP	Receptacles
EXT	Exterior lighting
REFR	Refrigeration
DISH	Dishwashing
DRY	Clothes drying
WASH	Clothes washing
COOK	Cooking
USER1	User-defined category 1
USER2	User-defined category 2
BT	Battery charge power
PV	Photovoltaic power generation

Units	Legal Range	Default	Required	Variability
	Codes listed above	none	Required if gnMeter is given	constant

The gnFrZn, gnFrPl, and gnFrRtn members allow you to allocate the gain among the zone, the zone’s plenum, and the zone’s return air flow. Values that total to more than 1.0 constitute an error. If they total less than 1, the unallocated portion of the gain is recorded by the meter (if specified) but not transferred into the building. By default, all of the gain not directed to the return or plenum goes to the zone.

gnFrZn=float

Fraction of gain going to zone. gnFrLat (below) gives portion of this gain that is latent, if any; the remainder is sensible.

Units	Legal Range	Default	Required	Variability
	0 \(\leq\) x \(\leq\) 1	1.	No	hourly

gnFrPl=float

Fraction of gain going to plenum.

Units	Legal Range	Default	Required	Variability
	gnFrZn + gnFrPl + gnFrRtn \(\leq\) 1	0.	No	hourly

gnFrRtn=float

Fraction of gain going to return.

Units	Legal Range	Default	Required	Variability
	gnFrZn + gnFrPl + gnFrRtn \(\leq\) 1	0.	No	hourly

gnFrRad=float

Fraction of total gain going to zone (gnFrZn) that is radiant rather than convective or latent.

Units	Legal Range	Default	Required	Variability
	0 \(\leq\) x \(\leq\) 1	0.0	No	hourly

gnFrLat=float

Fraction of total gain going to zone (gnFrZn) that is latent heat (moisture addition).

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.0	No	hourly

gnDlFrPow=float

Hourly power reduction factor, typically used to modify lighting power to account for daylighting.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	1.0	No	hourly

gnCtrlDHWSYS=dhwsysName

Name of a DHWSYS whose water use modulates gnPower. For example, electricity use of water-using appliances (e.g. dishwasher or clothes washer) can be modeled based on water use, ensuring that the uses are synchronized. When this feature is used, gnPower should be specified in Btuh/gal.

Units	Legal Range	Default	Required	Variability
	name of a DHWSYS	no DHWSYS/GAIN linkage	No	constant

gnCtrlDHWMETER=dhwMtrName

Allows gains to track water usage such as dishwashers, clothes washers, etc.

Units	Legal Range	Default	Required	Variability
	name of DHWMETER	0	No	constant

gnCtrlDHWEndUse=dhwEndUseName

Name of the DHWSYS end use consumption that modulates gnPower. See DHWMETER for DHW end use definitions.

Units	Legal Range	Default	Required	Variability
	DHW end use	Total	No	constant

endGain

Optional to indicate the end of the GAIN definition. Alternatively, the end of the gain definition can be indicated by END or by the declaration of another object.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @gain

4.16 SURFACE

Surface constructs a ZONE subobject of class SURFACE that represents a surrounding or interior surface of the zone. Internally, SURFACE generates a QUICK surface (U-value only), a DELAYED (massive) surface (using the finite-difference mass model), interzone QUICK surface, or interzone DELAYED surface, as appropriate for the specified construction and exterior conditions.

sfName

Name of surface; give after the word SURFACE.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

sfType=choice

Type of surface:

FLOOR	Surface defines part or all of the ‘bottom’ of the zone; it is horizontal with inside facing up. The outside of the surface is not adjacent to the current zone.
WALL	Surface defines a ‘side’ of the zone; its outside is not adjacent to the current zone.
CEILING	Surface defines part or all of the ‘top’ of the zone with the inside facing down. The outside of the surface is not adjacent to the current zone.

sfType is used extensively for default determination and input checking, but does not have any further internal effect. The Floor, Wall, and Ceiling choices identify surfaces that form boundaries between the zone and some other condition.

Units	Legal Range	Default	Required	Variability
	FLOOR WALL CEILING	none	Yes	constant

sfArea=float

Gross area of surface. (CSE computes the net area for simulation by subtracting the areas of any windows and doors in the surface.).

Units	Legal Range	Default	Required	Variability
ft2	x \(>\) 0	none	Yes	constant

sfTilt=float

Surface tilt from horizontal. Values outside the range 0 to 360 are first normalized to that range. The default and allowed range depend on sfType, as follows:

sfType = FLOOR	sfTilt=180, default = 180 (fixed value)
sfType = WALL	60 \(<\) sfTilt \(<\) 180, default = 90
sfType = CEILING	0 \(\leq\) sfTilt \(\leq\) 60, default = 0

Units	Legal Range	Default	Required	Variability
degrees	Dependent upon sfType See above	Dependent upon sfType See above	No	constant

sfAzm=float

Azimuth of surface with respect to znAzm. The azimuth used in simulating a surface is bldgAzm + znAzm + sfAzm; the surface is rotated if any of those are changed. Values outside the range 0 to 360 are normalized to that range. Required for non-horizontal surfaces.

Units	Legal Range	Default	Required	Variability
degrees	unrestricted	none	Required if sfTilt \(\neq\) 0 and sfTilt \(\neq\) 180	constant

sfModel=choice

Provides user control over how CSE models conduction for this surface.

QUICK	Surface is modeled using a simple conductance. Heat capacity effects are ignored. Either sfCon or sfU (next) can be specified.
DELAYED, DELAYED_HOUR, DELAYED_SUBHOUR	Surface is modeled using a multi-layer finite difference technique that represents heat capacity effects. If the time constant of the surface is too short to accurately simulate, a warning message is issued and the Quick model is used. The program cannot use the finite difference model if sfU rather than sfCon is specified.
AUTO	Program selects Quick or the appropriate Delayed automatically according to the time constant of the surface (if sfU is specified, Quick is selected).
FD (or FORWARD_DIFFERENCE)	Selects the forward difference model (used with short time steps and the CZM/UZM zone model).
KIVA	Uses a two-dimensional finite difference model to simulate heat flow through foundation surfaces.

Units	Legal Range	Default	Required	Variability
–	QUICK, DELAYED, DELAYED_HOUR, DELAYED_SUBOUR , AUTO, 2D_FND	AUTO	No	constant

Either sfU or sfCon must be specified, but not both.

sfU=float

Surface U-value (NOT including surface (air film) conductances). For surfaces for which no heat capacity is to be modeled, allows direct entry of U-value without defining a CONSTRUCTION.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	Determined from sfCon	if sfCon not given	constant

sfCon=conName

Name of CONSTRUCTION of the surface.

Units	Legal Range	Default	Required	Variability
	Name of a CONSTRUCTION	none	unless sfU given	constant

sfLThkF=float

Sublayer thickness adjustment factor for FORWARD_DIFFERENCE conduction model used with sfCon surfaces. Material layers in the construction are divided into sublayers as needed for numerical stability. sfLThkF allows adjustment of the thickness criterion used for subdivision. A value of 0 prevents subdivision; the default value (0.5) uses layers with conservative thickness equal to half of an estimated safe value. Fewer (thicker) sublayers improves runtime at the expense of accurate representation of rapid changes.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	0.5	No	constant

sfExCnd=choice

Specifies the thermal conditions assumed at surface exterior, and at exterior of any subobjects (windows or doors) belonging to current surface. The conditions accounted for are dry bulb temperature and incident solar radiation.

AMBIENT	Exterior surface is exposed to the ‘weather’ as read from the weather file. Solar gain is calculated using solar geometry, sfAzm, sfTilt, and sfExAbs.
SPECIFIEDT	Exterior surface is exposed to solar radiation as in AMBIENT, but the dry bulb temperature is calculated with a user specified function (sfExT). sfExAbs can be set to 0 to eliminate solar effects.
ADJZN	Exterior surface is exposed to another zone, whose name is specified by sfAdjZn. Solar gain is 0 unless gain is targeted to the surface with SGDIST below.
GROUND	The surface is in contact with the ground. Details of the two-dimensional foundation design are defined by sfFnd. Only floor and wall surfaces may use this option.
ADIABATIC	Exterior surface heat flow is 0. Thermal storage effects of delayed surfaces are modeled.

sfExAbs=float

Surface exterior absorptivity.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.5	Required if sfExCnd = AMBIENT or sfExCnd = SPECIFIEDT	monthly-hourly

sfInAbs=float

Surface interior solar absorptivity.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(le\) 1	sfType = CEILING, 0.2; sfType = WALL, 0.6; sfType = FLOOR, 0.8	No	monthly-hourly

sfExEpsLW=float

Surface exterior long wave (thermal) emittance.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.9	No	constant

sfInEpsLW=float

Surface interior long wave (thermal) emittance.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.9	No	constant

sfExT=float

Exterior air temperature.

Units	Legal Range	Default	Required	Variability
oF	unrestricted	none	Required if sfExCnd = SPECIFIEDT	hourly

sfAdjZn=znName

Name of adjacent zone; used only when sfExCnd is ADJZN. Can be the same as the current zone.

Units	Legal Range	Default	Required	Variability
	name of a ZONE	none	Required when sfExCnd = ADJZN	constant

sfGrndRefl=float

Ground reflectivity for this surface.

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	grndRefl	No	Monthly - Hourly

sfInH=float

Inside surface (air film) conductance. Ignored for sfModel = Forward_Difference. Default depends on the surface type.

sfType = FLOOR or CEILING	1.32
other	1.5

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	See above	No	constant

sfExH=float

Outside combined surface (air film) conductance. Ignored for sfModel = Forward_Difference. The default value is dependent upon the exterior conditions:

sfExCnd = AMBIENT	dflExH (Top-level member, described above)
sfExCnd = SPECIFIEDT	dflExH (described above)
sfExCnd = ADJZN	1.5
sfExCnd = ADIABATIC	not applicable

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	see above	No	constant

When sfModel = Forward_Difference, several models are available for calculating inside and outside surface convective coefficients. Inside surface faces can be exposed only to zone conditions. Outside faces may be exposed either to ambient conditions or zone conditions, based on sfExCnd. Only UNIFIED and INPUT are typically used. The other models were used during CSE development for comparison. For details, see CSE Engineering Documentation.

Model	Exposed to ambient	Exposed to zone
UNIFIED	default CSE model	default CSE model
INPUT	hc = sfExHcMult	hc = sfxxHcMult
AKBARI	Akbari model	n/a
WALTON	Walton model	n/a
WINKELMANN	Winkelmann model	n/a
DOE2	DOE2 model	n/a
MILLS	n/a	Mills model
ASHRAE	n/a	ASHRAE handbook values
TARP	n/a	TARP model

sfExHcModel=choice

Selects the model used for exterior surface convection when sfModel = Forward_Difference.

Units	Legal Range	Default	Required	Variability
	choices above	UNIFIED	No	constant

sfExHcLChar=float

Characteristic length of surface, used in derivation of forced exterior convection coefficients in some models when outside surface is exposed to ambient. See sfExHcModel.

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	10	No	constant

sfExHcMult=float

Exterior convection coefficient adjustment factor. When sfExHcModel=INPUT, hc=sfExHcMult. For other sfExHcModel choices, the model-derived hc is multiplied by sfExHcMult.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	subhourly

sfExRf=float

Exterior surface roughness factor. Used only when surface is exposed to ambient (i.e. with wind exposure). Typical values:

Roughness Index	sfExRf	Example
1 (very rough)	2.17	Stucco
2 (rough)	1.67	Brick
3 (medium rough)	1.52	Concrete
4 (Medium smooth)	1.13	Clear pine
5 (Smooth)	1.11	Smooth plaster
6 (Very Smooth)	1	Glass

Units	Legal Range	Default	Required	Variability
		sfExHcModel = WINKELMANN: 1.66 else 2.17	No	constant

sfInHcModel=choice

Selects the model used for the inside (zone) surface convection when sfModel = Forward_Difference.

Units	Legal Range	Default	Required	Variability
	choices above (see sfExHcModel)	UNIFIED	No	constant

sfInHcMult=float

Interior convection coefficient adjustment factor. When sfInHcModel=INPUT, hc=sfInHcMult. For other sfInHcModel choices, the model-derived hc is multiplied by sfInHcMult.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	subhourly

The items below give values associated with CSE’s model for below grade surfaces (sfExCnd=GROUND). See CSE Engineering Documentation for technical details.

sfFnd=fdName

Name of FOUNDATION applied to ground-contact Floor SURFACEs; used only for Floor SURFACEs when sfExCnd is GROUND.

Units	Legal Range	Default	Required	**Variability
–	Name of a Foundation	none	when sfExCnd = GROUND and sfType = Floor	constant

sfFndFloor=sfName

Name of adjacent ground-contact Floor SURFACE; used only for Wall SURFACEs when sfExCnd is GROUND.

Units	Legal Range	Default	Required	Variability
–	Name of a Surface	none	when sfExCnd = GROUND and sfType = Wall	constant

sfHeight=float

Needed for foundation wall height, otherwise ignored. Maybe combine with sfDepthBG?

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	none	when sfType is WALL and sfExtCnd is GROUND	constant

sfExpPerim=float

Exposed perimeter of foundation floors.

Units	Legal Range	Default	Required	Variability
ft	x \(\geq\) 0	none	when sfType is FLOOR, sfFnd is set, and sfExtCnd is GROUND	constant

sfDepthBG=float

Note: sfDepthBG is used as part of the simple ground model, which is no longer supported. Use sfHeight with sfFnd instead.

Depth below grade of surface. For walls, sfDepthBG is measured to the lower edge. For floors, sfDepthBG is measured to the bottom face.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	none	No	constant

Note: The following data members are part of the simple ground model, which is no longer supported. Use sfFnd instead.

sfExCTGrnd=float

sfExCTaDbAvg07=float

sfExCTaDbAvg14=float

sfExCTaDbAvg31=float

sfExCTaDbAvgYr=float

Conductances from outside face of surface to the weather file ground temperature and the moving average outdoor dry-bulb temperatures for 7, 14, 31, and 365 days.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(\ge\) 0	see above	No	constant

sfExRConGrnd=float

Resistance overall construction resistance. TODO: full documentation.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	none	No	constant

endSURFACE

Optional to indicates the end of the surface definition. Alternatively, the end of the surface definition can be indicated by END, or by beginning another SURFACE or other object definition. If used, should follow the definitions of the SURFACE’s subobjects – DOORs, WINDOWs, SHADEs, SGDISTs, etc.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @surface
• @xsurf
• @mass

4.17 WINDOW

WINDOW defines a subobject belonging to the current SURFACE that represents one or more identical windows. The azimuth, tilt, and exterior conditions of the window are the same as those of the surface to which it belongs. The total window area (wnHt \(\cdot\) wnWid \(\cdot\) wnMult) is deducted from the gross surface area. A surface may have any number of windows.

Windows may optionally have operable interior shading that reduces the overall shading coefficient when closed.

wnName

Name of window: follows the word “WINDOW” if given.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

wnHeight=float

Overall height of window (including frame).

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	none	Yes	constant

wnWidth=float

Overall width of window (including frame).

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	none	Yes	constant

wnArea=float

Overall area of window (including frame).

Units	Legal Range	Default	Required	Variability
ft2	x \(>\) 0	wnHeight wnWidth*	No	constant

wnMult=float

Area multiplier; can be used to represent multiple identical windows.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

wnModel=choice

Selects window model

Units	Legal Range	Default	Required	Variability
	SHGC, ASHWAT	SHGC	No	constant

wnGt=choice

GLAZETYPE for window. Provides many defaults for window properties as cited below.

wnU=float

Window conductance (U-factor without surface films, therefore not actually a U-factor but a C-factor).

Preferred Approach: To use accurately with standard winter rated U-factor from ASHRAE or NFRC enter as:

    wnU = (1/((1/U-factor)-0.85)

Where 0.85 is the sum of the interior (0.68) and exterior (0.17) design air film resistances assumed for rating window U-factors. Enter wnInH (usually 1.5=1/0.68) instead of letting it default. Enter the wnExH or let it default. It is important to use this approach if the input includes gnFrad for any gain term. Using approach 2 below will result in an inappropriate internal gain split at the window.

Approach 2. Enter wnU=U-factor and let the wnInH and wnExH default. Tnormally this approach systematically underestimates the window U-factor because it adds the wnExfilm resistance to 1/U-factor thereby double counting the exterior film resistance. This approach will also yield incorrect results for gnFrad internal gain since the high wnInH will put almost all the gain back in the space.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	none	Yes	constant

wnUNFRC=float

Fenestration system (including frame) U-factor evaluated at NFRC heating conditions.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	gtUNFRC	Required when wnModel = ASHWAT	constant

wnExEpsLW=float

Window exterior long wave (thermal) emittance.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.84	No	constant

wnInEpsLW=float

Window interior long wave (thermal) emittance.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.84	No	constant

wnInH=float

Window interior surface (air film) conductance.

Preferred Approach: Enter the appropriate value for each window, normally:

    wnInH = 1.5

    where 1.5 = 1/0.68 the standard ASHRAE value.

The large default value of 10,000 represents a near-0 resistance, for the convenience of those who wish to include the interior surface film in wnU according to approach 2 above.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	10000	No	constant

wnExH=float

Window exterior surface (air film) conductance.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	same as owning surface	No	constant

Several models are available for calculating inside and outside surface convective coefficients. Inside surface faces can be exposed only to zone conditions. Outside faces may be exposed either to ambient conditions or zone conditions, based on wnExCnd. Only UNIFIED and INPUT are typically used. The other models were used during CSE development for comparison. For details, see CSE Engineering Documentation.

Model	Exposed to ambient	Exposed to zone
UNIFIED	default CSE model	default CSE model
INPUT	hc = wnExHcMult	hc = wnxxHcMult
AKBARI	Akbari model	n/a
WALTON	Walton model	n/a
WINKELMANN	Winkelmann model	n/a
MILLS	n/a	Mills model
ASHRAE	n/a	ASHRAE handbook values

wnExHcModel=choice

Selects the model used for exterior surface convection when wnModel = Forward_Difference.

Units	Legal Range	Default	Required	Variability
	choices above	UNIFIED	No	constant

wnExHcLChar=float

Characteristic length of surface, used in derivation of forced exterior convection coefficients in some models when outside face is exposed to ambient (i.e. to wind).

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	10	No	constant

wnExHcMult=float

Exterior convection coefficient adjustment factor. When wnExHcModel=INPUT, hc=wnExHcMult. For other wnExHcModel choices, the model-derived hc is multiplied by wnExHcMult.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	subhourly

wnInHcModel=choice

Selects the model used for the inside (zone) surface convection when wnModel = Forward_Difference.

Units	Legal Range	Default	Required	Variability
	choices above (see wnExHcModel)	UNIFIED	No	constant

wnInHcMult=float

Interior convection coefficient adjustment factor. When wnInHcModel=INPUT, hc=wnInHcMult. For other wnInHcModel choices, the model-derived hc is multiplied by wnInHcMult.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	subhourly

wnSHGC=float

Rated Solar Heat Gain Coefficient (SHGC) for the window assembly.

Units	Legal Range	Default	Required	Variability
fraction	0 < x < 1	gtSHGC	No	constant

wnFMult=float

Frame area multiplier = areaGlaze / areaAssembly

Units	Legal Range	Default	Required	Variability
fraction	0 < x < 1	gtFMult or 1	No	constant

wnSMSO=float

SHGC multiplier with shades open. Overrides gtSMSO.

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	gtSMSO or 1	No	Monthly - Hourly

wnSMSC=float

SHGC multiplier with shades closed. Overrides gtSMSC

Units	Legal Range	Default	Required	Variability
fraction	0 \(leq\) x \(leq\) 1	wnSMSO or gtSMSC	No	Monthly - Hourly

wnNGlz=int

Number of glazings in the window (bare glass only, not including any interior or exterior shades).

Units	Legal Range	Default	Required	Variability
	0 \(<\) x \(leq\) 4	gtNGLZ	Required when wnModel = ASHWAT	constant

wnExShd=choice

Exterior shading type (ASHWAT only).

Units	Legal Range	Default	Required	Variability
	NONE, INSCRN	gtExShd	No	constant

wnInShd=choice

Interior shade type (ASHWAT only).

Units	Legal Range	Default	Required	Variability
	NONE, DRAPEMED	gtInShd	No	constant

wnDirtLoss=float

Glazing dirt loss factor.

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	none	No	constant

wnGrndRefl=float

Ground reflectivity for this window.

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	sfGrndRefl	No	Monthly - Hourly

wnVfSkyDf=float

View factor from this window to sky for diffuse radiation. For the shading effects of an overhang, a wnVfSkyDf value smaller than the default would be used

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	0.5 - 0.5 cos(tilt) = .5 for vertical surface	No	Monthly - Hourly

wnVfGrndDf=float

View factor from this window to ground for diffuse radiation. For the shading effects of a fin(s), both wnVfSkyDf and wnVfGrndDf would be used.

Units	Legal Range	Default	Required	Variability
fraction	0 \(\leq\) x \(\leq\) 1	0.5 + 0.5 .5 for vertical surface	No	Monthly - Hourly

endWINDOW

Optionally indicates the end of the window definition. Alternatively, the end of the window definition can be indicated by END or the declaration of another object. END or endWindow, if used, should follow any subobjects of the window (SHADEs and/or SGDISTs).

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @window
• @xsurf

4.18 SHADE

SHADE constructs a subobject associated with the current WINDOW that represents fixed shading devices (overhangs and/or fins). A window may have at most one SHADE and only windows in vertical surfaces may have SHADEs. A SHADE can describe an overhang, a left fin, and/or a right fin; absence of any of these is specified by omitting or giving 0 for its depth. SHADE geometry can vary on a monthly basis, allowing modeling of awnings or other seasonal shading strategies.

shName

Name of shade; follows the word “SHADE” if given.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

ohDepth=float

Depth of overhang (from plane of window to outside edge of overhang). A zero value indicates no overhang.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	monthly-hourly

ohDistUp=float

Distance from top of window to bottom of overhang.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	monthly-hourly

ohExL=float

Distance from left edge of window (as viewed from the outside) to the left end of the overhang.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	monthly-hourly

ohExR=float

Distance from right edge of window (as viewed from the outside) to the right end of the overhang.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	monthly-hourly

ohFlap=float

Height of flap hanging down from outer edge of overhang.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	monthly-hourly

lfDepth=float

Depth of left fin from plane of window. A zero value indicates no fin.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	monthly-hourly

lfTopUp=float

Vertical distance from top of window to top of left fin.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	monthly-hourly

lfDistL=float

Distance from left edge of window to left fin.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	monthly-hourly

lfBotUp=float

Vertical distance from bottom of window to bottom of left fin.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	monthly-hourly

rfDepth=float

Depth of right fin from plane of window. A 0 value indicates no fin.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	monthly-hourly

rfTopUp=float

Vertical distance from top of window to top of right fin.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	monthly-hourly

rfDistR=float

Distance from right edge of window to right fin.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	monthly-hourly

rfBotUp=float

Vertical distance from bottom of window to bottom of right fin.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	monthly-hourly

endShade

Optional to indicate the end of the SHADE definition. Alternatively, the end of the shade definition can be indicated by END or the declaration of another object.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @shade

4.19 SGDIST

SGDIST creates a subobject of the current window that distributes a specified fraction of that window’s solar gain to a specified delayed model (massive) surface. Any remaining solar gain (all of the window’s solar gain if no SGDISTs are given) is added to the air of the zone containing the window. A window may have up to three SGDISTs; an error occurs if more than 100% of the window’s gain is distributed.

Via members sgFSO and sgFSC, the fraction of the insolation distributed to the surface can be made dependent on whether the zone’s shades are open or closed (see ZONE member znSC).

sgName

Name of solar gain distribution (follows “SGDIST” if given).

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

sgSurf=sfName

Name of surface to which gain is targeted.

If there is more than surface with the specified name: if one of the surfaces is in the current zone, it is used; otherwise, an error message is issued.

The specified surface must be modeled with the Delayed model. If gain is targeted to a Quick model surface, a warning message is issued and the gain is redirected to the air of the associated zone.

Units	Legal Range	Default	Required	Variability
	name of a SURFACE	none	Yes	constant

sgSide=choice

Designates the side of the surface to which the gain is to be targeted:

INTERIOR	Apply gain to interior of surface
EXTERIOR	Apply gain to exterior of surface

Units	Legal Range	Default	Required	Variability
	INTERIOR, EXTERIOR	Side of surface in zone containing window; or INTERIOR if both sides are in zone containing window.	Yes	constant

sgFSO=float

Fraction of solar gain directed to specified surface when the owning window’s interior shading is in the open position (when the window’s zone’s shade closure (znSC) is 0).

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1,and sum of window’s sgFSO’s \(\le\) 1	none	Yes	monthly-hourly

sgFSC=float

Fraction of solar gain directed to specified surface when the owning window’s interior shading is in the closed position. If the zone’s shades are partly closed (znSC between 0 and 1), a proportional fraction between sgFSO and sgFSC is used.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1, and sum of window’s sgFSC’s \(\le\) 1	sgFSO	No	monthly-hourly

endSGDist

Optionally indicates the end of the solar gain distribution definition. Alternatively, the end of the solar gain distribution definition can be indicated by END or by just beginning another object.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @sgdist

4.20 DOOR

DOOR constructs a subobject belonging to the current SURFACE. The azimuth, tilt, ground reflectivity and exterior conditions associated with the door are the same as those of the owning surface, although the exterior surface conductance and the exterior absorptivity can be altered.

drName

Name of door.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

drArea=float

Overall area of door.

Units	Legal Range	Default	Required	Variability
ft2	x \(>\) 0	none	Yes	constant

drModel=choice

Provides user control over how CSE models conduction for this door:

QUICK	Surface is modeled using a simple conductance. Heat capacity effects are ignored. Either drCon or drU (next) can be specified.
DELAYED, DELAYED_HOUR, DELAYED_SUBOUR	Surface is modeled using a multi-layer finite difference technique which represents heat capacity effects. If the time constant of the door is too short to accurately simulate, a warning message is issued and the Quick model is used. drCon (next) must be specified – the program cannot use the finite difference model if drU rather than drCon is specified.
AUTO	Program selects Quick or appropriate Delayed automatically according to the time constant of the surface (if drU is specified, Quick is selected).
FD or FORWARD_DIFFERENCE	Selects the forward difference model (used with short time steps and the CZM/UZM zone models)

Units	Legal Range	Default	Required	Variability
	choices above	AUTO	No	constant

Either drU or drCon must be specified, but not both.

drU=float

Door U-value, NOT including surface (air film) conductances. Allows direct entry of U-value, without defining a CONSTRUCTION, when no heat capacity effects are to be modeled.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	Determined from drCon	if drCon not given	constant

drCon=conName

Name of construction for door.

Units	Legal Range	Default	Required	Variability
	name of a CONSTRUCTION	none	unless drU given	constant

drLThkF=float

Sublayer thickness adjustment factor for FORWARD_DIFFERENCE conduction model used with drCon surfaces. Material layers in the construction are divided into sublayers as needed for numerical stability. drLThkF allows adjustment of the thickness criterion used for subdivision. A value of 0 prevents subdivision; the default value (0.5) uses layers with conservative thickness equal to half of an estimated safe value. Fewer (thicker) sublayers improves runtime at the expense of accurate representation of rapid changes.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	0.5	No	constant

drExAbs=float

Door exterior solar absorptivity. Applicable only if sfExCnd of owning surface is AMBIENT or SPECIFIEDT.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	same as owning surface	No	monthly-hourly

drInAbs=float

Door interior solar absorptivity.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.5	No	monthly-hourly

drExEpsLW=float

Door exterior long wave (thermal) emittance.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.9	No	constant

drInEpsLW=float

Door interior long wave (thermal) emittance.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.9	No	constant

drInH=float

Door interior surface (air film) conductance. Ignored if drModel = Forward_Difference

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	same as owning surface	No	constant

drExH=float

Door exterior surface (air film) conductance. Ignored if drModel = Forward_Difference

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	same as owning surface	No	constant

When drModel = Forward_Difference, several models are available for calculating inside and outside surface convective coefficients. Inside surface faces can be exposed only to zone conditions. Outside faces may be exposed either to ambient conditions or zone conditions, based on drExCnd. Only UNIFIED and INPUT are typically used. The other models were used during CSE development for comparison. For details, see CSE Engineering Documentation.

Model	Exposed to ambient	Exposed to zone
UNIFIED	default CSE model	default CSE model
INPUT	hc = drExHcMult	hc = drxxHcMult
AKBARI	Akbari model	n/a
WALTON	Walton model	n/a
WINKELMANN	Winkelmann model	n/a
MILLS	n/a	Mills model
ASHRAE	n/a	ASHRAE handbook values

drExHcModel=choice

Selects the model used for exterior surface convection when drModel = Forward_Difference.

Units	Legal Range	Default	Required	Variability
	choices above	UNIFIED	No	constant

drExHcLChar=float

Characteristic length of surface, used in derivation of forced exterior convection coefficients in some models when outside face is exposed to ambient (i.e. to wind).

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	10	No	constant

drExHcMult=float

Exterior convection coefficient adjustment factor. When drExHcModel=INPUT, hc=drExHcMult. For other drExHcModel choices, the model-derived hc is multiplied by drExHcMult.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	subhourly

drExRf=float

Exterior roughness factor. Typical roughness values:

Roughness Index	drExRf	Example
1 (very rough)	2.17	Stucco
2 (rough)	1.67	Brick
3 (medium rough)	1.52	Concrete
4 (Medium smooth)	1.13	Clear pine
5 (Smooth)	1.11	Smooth plaster
6 (Very Smooth)	1	Glass

Units	Legal Range	Default	Required	Variability
		drExHcModel = WINKELMANN: 1.66 else 2.17	No	constant

drInHcModel=choice

Selects the model used for the inside (zone) surface convection when drModel = Forward_Difference.

Units	Legal Range	Default	Required	Variability
	choices above (see drExHcModel)	UNIFIED	No	constant

drInHcMult=float

Interior convection coefficient adjustment factor. When drInHcModel=INPUT, hc=drInHcMult. For other drInHcModel choices, the model-derived hc is multiplied by drInHcMult.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	subhourly

endDoor

Indicates the end of the door definition. Alternatively, the end of the door definition can be indicated by the declaration of another object or by END.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @door
• @xsurf
• @mass

4.21 PERIMETER

PERIMETER defines a subobject belonging to the current zone that represents a length of exposed edge of a (slab on grade) floor.

prName

Optional name of perimeter.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

prLen=float

Length of exposed perimeter.

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	none	Yes	constant

prF2=float

Perimeter conduction per unit length.

Units	Legal Range	Default	Required	Variability
Btuh/ft-oF	x \(>\) 0	none	Yes	constant

endPerimeter

Optionally indicates the end of the perimeter definition.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @perimeter
• @xsurf

4.22 TERMINAL

TERMINAL constructs an object to represent equipment that transfers energy to or from the current zone from a local heating device (coil, etc.) and/or one AIRHANDLER. A terminal serves a zone (and, internally, is owned by a zone). Up to three terminals can be defined for each zone.

A terminal can have local heating capability, using a simulated reheat coil, baseboard heater, etc. and/or air heating/cooling capability, using a simulated variable air volume (VAV) box connected to an AIRHANDLER (Section 0). Since a TERMINAL can only connect to a single air handler, use two terminals per zone to model systems where separate air handlers supply hot and cool air (dual duct). If a local heat capability utilizes the air flow (e.g. a reheat coil), model it in the terminal connected to the air handler; if a local heat capability is independent of air flow (e.g. electric baseboard heaters), it doesn’t matter whether you model it with a separate terminal.

Each capability can be set output, in which the output is constant or determined by external conditions such as in an outdoor reset baseboard situation or set temperature, in which the output is modulated to maintain the zone temperature at a set point. Set temperature operation is established by giving the setpoint for the capability (tuTLh, tuTH, tuTC); set output operation is established by specifying the local heat output (tuQMnLh) or air flow (tuVfMn) without specifying a setpoint.

Hourly variable expressions may be used as desired to schedule setpoints and flow limits. Figure 1 shows [need sentence describing the figure.]

tuName

Optional name of terminal; follows the word “TERMINAL” if given.

Units	Legal Range	Default	Required	Variability
	63 characters		No	constant

4.22.1 TERMINAL Local Heating

These commands establish the TERMINAL’s local heating capability and determine whether it operates in set output or set temperature fashion. Additional details of the local heating mechanism are given with commands described below under terminal heating coil.

Either tuTLh or tuQMnLh must be given to establish the TERMINAL’s local heat capability:

tuTLh=float

Local heating thermostat setpoint. Hourly expression may be used to schedule as desired. Giving this implies set temperature local heat from this terminal; omitting implies no local heat or, if tuQMnLh is given, set output local heat.

Units	Legal Range	Default	Required	Variability
oF	x \(>\) 0	no thermostat control	No	hourly

tuQMnLh=float

Minimum local heat output or set local heat output. If tuTLh is given, this is the minimum output, used when the thermostat is not calling for (local) heat. If tuTLh is not given, giving tuQMnLh implies set output local heat and specifies the set output level. An hourly expression may be used to schedule as desired.

Units	Legal Range	Default	Required	Variability
Btuh	x \(\ge\) 0	0 if tuTLh given else no local heat	For set output local heat	hourly

The next three items are allowed only for thermostat controlled local heating (tuTLh given):

tuQMxLh=float

Maximum desired power, used when thermostat is calling for heat continuously, subject to coil capacity, and to HEATPLANT limitations where pertinent (see tuhcCaptRat description). If tuQMxLh is less than minimum power (tuQMnLh), the latter is used, effectively disabling setpoint control.

Units	Legal Range	Default	Required	Variability
Btuh	x \(\ge\) 0		Yes, if tuTLh given	hourly

tuPriLh=int

Setpoint priority: when there is more than one capability with the same setpoint, that with the highest priority (lowest value) is used first. The defaults for tuPriLh (100) and tuPriH (1) cause maximum air heat to be used before local heat, if both are present and the setpoints are the same. Two or more equal setpoints with equal priorities in the ZONE cause an error, even if in different TERMINALs.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	100	No	constant

tuLhNeedsFlow=choice

YES	local heat being modeled requires terminal air flow (e.g. reheat coil). Local heat is then disabled when there is zero air flow through the terminal (when simulated VAV damper set to 0 flow, or when air handler fan and terminal fan both off)
NO	no local heat or does not require air flow (e.g. baseboard heaters).

Units	Legal Range	Default	Required	Variability
	YES, NO	NO	No	constant

4.22.2 TERMINAL Air Heating and Cooling

These commands establish whether the TERMINAL has air capability (heat, cool, or both), and whether the capability operates in set temperature mode (tuTH and/or tuTLh given) or set output mode (tuVfMn given without tuTH and tuTLh). They further establish the setpoints, flow limits, leakages, and losses.

Caution should be exercised in using air heat and air cooling in the same terminal. The supply air for both comes from the same air handler; it is up to you to make sure the terminal only calls for heat when the air handler is blowing hot air and only calls for cooling when the air handler is blowing cold air. This is done by carefully coordinating the variable expressions for terminal air heating and cooling setpoints (tuTH and tuTC here) and the air handler supply temperature setpoint (AIRHANDLER ahTsSp, Section 0).

Note: To autosize air flows for a constant volume terminal, use the following

AUTOSIZE tuVfMxC
AUTOSIZE tuVfMxH
AUTOSIZE tuVfMn
tuVfMxHC = SAME

tuAh=ahName

Name of air handler supplying this terminal.

Units	Legal Range	Default	Required	Variability
	name of an AIRHANDLER	If omitted, terminal has no air heating nor cooling capability.	No	constant

If both of the following (tuTH and tuTC) are specified, be careful not to accidentally permit the heating setpoint to be active when the air handler is blowing cold air, or vice versa. CSE’s simulated thermostats and VAV boxes are at least as dumb as their real counterparts; if the thermostat calls for heat, the VAV damper will open even if the supply air is colder than the zone. To schedule deactivation of the air heating or cooling capability, schedule an extreme setpoint, such as 1 for heating or 199 for cooling.

Giving neither tuTH nor tuTC implies that the terminal has no set temperature air capability; it will then have set output air capability if tuVfMn is given.

tuTH=float

Air heating thermostat set point; implies set temperature air capability. May be scheduled as desired with an hourly expression; to disable set temperature operation at certain times (as when air handler is scheduled to supply cold air), schedule a low temperature such as 1.

Units	Legal Range	Default	Required	**Variability
oF	x \(\ge\) 0	No thermostat-controlled air heating	No	hourly

tuTC=float

Air cooling thermostat set point; implies set temperature air capability. May be scheduled as desired; to disable at certain times, schedule an extreme temperature such as 199.

Units	Legal Range	Default	Required	**Variability
oF	x \(\ge\) 0	No thermostat-controlled air cooling	No	hourly

tuVfDs=float

Design air flow rate. (“Vf” in member names stands for “Volumetric Flow”, to emphasize that flow is specified by volume at actual air temperature (cfm), not by mass (lb/hr), nor heat capacity (Btuh/F), etc.)

The design air flow rate is used to apportion the available cfm among the terminals when the total flow demand of the terminals exceeds the air handler’s supply fan capacity; it is unimportant (but may nevertheless be required) if the total of the tuVfMx’s of the terminals on the air handler is not greater than the air handler’s fan capacity including overrun.

CSE will default tuVfDs to the largest of tuVfMn, tuVfMxH, and tuVfMxC unless a variable expression is given for any of them. Thus, you must given tuVfDs only when a variable minimum or maximum flow is used, or when you wish to override the default cfm apportionment under fan overload conditions.

Units	Legal Range	Default	Required	Variability
cfm	x \(\ge\) 0	largest of tuVfMn, tuVfMxH, and tuVfMxC if all are constant	Yes, if tuVfmn, tuVfmxH, or tuVfMxC is variable	hourly

tuFxVfHC=float

Sizing factor for autosized terminal air flows. Default value (1.1) specifies 10% oversizing.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1.1	No	constant

tuVfMxHC=choice

Determines autosizing strategy for heating and cooling air flows.

SAME	tuVfMxH and tuVfMxC are set to the larger of the autosized values
DIFFERENT	tuVfMxH and tuVfMxC are autosized independently

Units	Legal Range	Default	Required	Variability
	choices above	Different	No	constant

tuVfMn=float

Minimum terminal air flow rate or set output air flow rate. An hourly expression may be used to schedule the minimum or set output flow as desired.

If neither tuTH nor tuTC is given, giving tuVfMn implies set output air capability for the terminal; the tvVfMn value is the set output cfm.

If either setpoint (tuTH or tuTC) is given, tuVfMn is the cfm used when the thermostat is not calling for heat nor cold; it might be non-0, for example, to meet ventilation requirements. If tuVfMn is larger than tuVfMxH (when heating) or tuVfMxC (when cooling), it overrules them; thus a minimum (e.g. ventilation) requirement need not be considered in formulating expressions for the maximum flows.

Units	Legal Range	Default	Required	Variability
cfm	AUTOSIZE or x \(\ge\) 0	if tuTH or tuTC given, else no air heat/cool	For set output air operation	hourly

tuVfMxH=float

Maximum heating air flow rate, subject to air handler limitations. This terminal flow is used when the thermostat is calling for heat continuously. Hourly schedulable. If not greater than tuVfMn, the latter flow is used, thus disabling thermostat control.

Units	Legal Range	Default	Required	Variability
cfm	AUTOSIZE or x \(\ge\) 0	none	If tuTH given	hourly

tuVfMxC=float

Maximum cooling air flow rate, before air handler limitations, used when the thermostat is calling for cooling continuously. tuVfMn overrides if larger.

Units	Legal Range	Default	Required	Variability
cfm	AUTOSIZE or x \(\ge\) 0	none	If tuTC given	hourly

tuPriC=int

Cool setpoint priority. The lowest numbered priority is used first when there are equal setpoints in a zone; equal heat or cool setpoints with equal priority in same ZONE (even if on different TERMINALs) constitute an error.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

tuPriH=int

Heat setpoint priority. Lowest numbered priority is used first when there are equal setpoints in a zone. Default for tuPriLh is larger, so that by default local heat is not used unless maximum air heat is insufficient, when both local heat and air heat are present in zone and have same setpoint.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

tuSRLeak=float

Leakage of supply air to return, increasing supply volume and return temperature. Note that this is a fraction of current cfm, whereas air handler leak (before VAV dampers) is a fraction of maximum cfm. TfanOffLeak is added to this if terminal has a fan that is not running (future, 7-92).

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.05	No	constant

tuSRLoss=float

Supply air to return plenum heat loss as a fraction of supply air to return air temperature difference. Not allowed if return is ducted (no plenum).

NOT IMPLEMENTED as of July 1992 – Plenums are unimplemented.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.1	No	constant

4.22.3 TERMINAL Heating Coil

These members are disallowed if terminal has no local heating capability, that is, if neither tuTLh nor tuQMnLh is given.

tuhcType=choice

Local heating coil type:

ELECTRIC	Electric coil or heater, including separate heaters such as electric baseboards. 100% efficient; rated capacity always available.
HW	Hot water coil, using hot water from amHEATPLANT. Available capacity may be limited by HEATPLANT total capacity as well as by coil rated capacity.

Units	Legal Range	Default	Required	Variability
	ELECTRIC (future: HW)	ELECTRIC, or NONE if no local heat	No	constant

tuhcCaptRat=float

Rated capacity of the heating coil. The coil will never supply more heat than its capacity, even if tuQMxLh and/or tuQMnLh is greater. For an ELECTRIC coil, the capacity is always the rated capacity. For an HW coil, the capacity is the rated capacity when the HEATPLANT can supply it; when the total heat demanded from the HEATPLANT by all the HW coils in TERMINALs and AIRHANDLERs exceeds the HEATPLANT’s capacity, CSE reduces the capacities of all HW coils proportionately until the plant is not overloaded.

Units	Legal Range	Default	Required	Variability
Btu/hr	AUTOSIZE or x \(\gt\) 0	none	Yes	constant

tuhcFxCap=float

Capacity factor for autosized terminal heating coil. Default value (1.1) specifies 10% oversizing.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1.1	No	constant

tuhcMtr=mtrName

Name of meter, if any, which accumulates input energy for this coil. End use category used is “Htg”. Not allowed when tuhcType is HW, as the energy for an HW coil comes through a HEATPLANT; the input energy is accumulated to a meter by the HEATPLANT.

Units	Legal Range	Default	Required	Variability
	name of a METER	not recorded	No	constant

tuhcHeatplant=heatplantName

Name of HEATPLANT for HW coil; disallowed for other coil types.

Units	Legal Range	Default	Required	Variability
	name of a HEATPLANT	none	If tuhcType is HW	constant

4.22.4 TERMINAL Fan

Presence of a terminal fan is indicated by specifying a tfanType value other than NONE.

Terminal fans are NOT IMPLEMENTED as of July 1992.

tfanType=choice

Choice of:

NONE	No fan in this TERMINAL (default); input for other terminal fan members disallowed.
SERIES	Fan runs whenever scheduled ON (see tfanSched, next); if VAV cfm < terminal fan cfm (tfanVfDs), the additional flow comes from the return air.
PARALLEL	Fan runs when scheduled ON (see tfanSched) and terminal’s simulated VAV cfm is less than tfanVfDs plus tuVfMn ?? plus tuVfMn??. Terminal fan cfm is added to VAV cfm from AIRHANDLER to get cfm to ZONE.

Units	Legal Range	Default	Required	Variability
	NONE, SERIES, PARALLEL	none	Yes, if fan present	constant

tfanSched=choice

Terminal fan schedule. May be scheduled with an hourly variable expression.

OFF	fan does not run
ON	fan may run
HEATING	fan may run when local heat is in use
VAV	fan may run when AIRHANDLER supply fan is on or when doing setback headting and ssCtrl is ZONE_HEAT or BOTH (future).

A series fan (see tfanType) runs whenever on; a parallel fan runs only enough to keep terminal cfm at terminal minimum plus fan cfm; thus it may not run at all when the VAV flow from the AIRHANDLER is sufficient.

Units	Legal Range	Default	Required	Variability
	OFF, ON, HEATING, VAV	none	Yes (if fan present)	hourly

tfanOffLeak=float

Backdraft leakage when terminal fan off., as a fraction of tfanVfDs.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.1 if fan present	No	constant

tfanVfDs=float

Terminal fan design flow rate. To specify .x times zone or terminal cfm, use a CSE expression.

Units	Legal Range	Default	Required	Variability
cfm	x \(\le\) 0	none	Yes (if fan present)	constant

tfanPress=float

Terminal fan external static pressure.

Units	Legal Range	Default	Required	Variability
inches H2O	x \(\ge\) 0	0.3	No	constant

tfanEff=float

Terminal fan/motor/drive combined efficiency.

Units	Legal Range	Default	Required	Variability
	0 \(le\) x \(le\) 1	0.08	No	constant

tfanCurvePy=k0, k1, k2, k3, x0

k0 through k3 are the coefficients of a cubic polynomial for the curve relating fan relative energy consumption to relative air flow above the minimum flow x0. Up to five floats may be given, separated by commas. 0 is used for any omitted trailing values. The values are used as follows:

\[z = k_0 + k_1 \cdot (x - x_0)| + k_2 \cdot (x - x_0)|^2 + k_3 \cdot (x - x_0)|^3\]

where:

• \(x\) is the relative fan air flow (as fraction of tfanVfDs; 0 \(\le\) x \(\le\) 1);
• \(x_0\) is the minimum relative air flow (default 0);
• \((x - x_0)|\) is the “positive difference”, i.e. \((x - x_0)\) if \(x > x_0\); else 0;
• \(z\) is the relative energy consumption.

If \(z\) is not 1.0 for \(x\) = 1.0, a warning message is displayed and the coefficients are normalized by dividing by the polynomial’s value for \(x\) = 1.0.

Units	Legal Range	Default	Required	Variability
		0, 1, 0, 0, 0 (linear)	No	constant

tfanMtr=mtrName

Name of meter, if any, which is to record energy used by this terminal fan. The “fans” category is used.

Units	Legal Range	Default	Required	Variability
	name of a METER	not recorded	No	constant

endTerminal

Optional to indicates the end of terminal definition. Alternatively, the end of the door definition can be indicated by END or by beginning another object.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	none	No	constant

Related Probes:

• @terminal
• @zhx

4.23 IZXFER

IZXFER constructs an object that represents an interzone or zone/ambient heat transfer due to conduction and/or air transfer. The air transfer modeled by IZXFER transfers heat only; humidity transfer is not modeled as of July 2011. Note that SURFACE is the preferred way represent conduction between ZONEs.

The AIRNET types are used in a multi-cell pressure balancing model that finds zone pressures that produce net 0 mass flow into each zone. The model operates in concert with the znType=CZM or znType=UZM to represent ventilation strategies. During each time step, the pressure balance is found for two modes that can be thought of as “VentOff” (or infiltration-only) and “VentOn” (or infiltration+ventilation). The zone model then determines the ventilation fraction required to hold the desired zone temperature (if possible). AIRNET modeling methods are documented in the CSE Engineering Documentation.

Note that fan-driven types assume pressure-independent flow. That is, the specified flow is included in the zone pressure balance but the modeled fan flow does not change with zone pressure. The assumption is that in realistic configurations, zone pressure will generally be close to ambient pressure. Unbalanced fan ventilation in a zone without relief area will result in runtime termination due to excessively high or low pressure.

izName

Optional name of interzone transfer; give after the word “IZXFER” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

izNVType=choice

Choice specifying the type of ventilation or leakage model to be used.

NONE	No interzone ventilation
ONEWAY	Uncontrolled flow from izZn1 to izZn2 when izZn1 air temperature exceeds izZn2 air temperature (using ASHRAE high/low vent model).
TWOWAY	Uncontrolled flow in either direction (using ASHRAE high/low vent model).
AIRNETIZ	Single opening to another zone (using pressure balance AirNet model). Flow is driven by buoyancy.
AIRNETEXT	Single opening to ambient (using pressure balance AirNet model). Flow is driven by buoyancy and wind pressure.
AIRNETHORIZ	Horizontal (large) opening between two zones, used to represent e.g. stairwells. Flow is driven by buoyancy; simultaneous up and down flow is modeled.
AIRNETEXTFAN	Fan from exterior to zone (flow either direction).
AIRNETIZFAN	Fan between two zones (flow either direction).
AIRNETEXTFLOW	Specified flow from exterior to zone (either direction). Behaves identically to AIRNETEXTFAN except no electricity is consumed and no fan heat is added to the air stream.
AIRNETIZFLOW	Specified flow between two zones (either direction). Behaves identically to AIRNETIZFAN except no electricity is consumed and no fan heat is added to the air stream.
AIRNETHERV	Heat or energy recovery ventilator. Supply and exhaust air are exchanged with the exterior with heat and/or moisture exchange between the air streams. Flow may or may not be balanced.
AIRNETDOAS	Air supplied from and/or exhausted to a centralized DOAS fans.

Note that optional inputs izTEx, izWEx, and izWindSpeed can override the outside conditions assumed for ivNVTypes that are connected to ambient (AIRNETEXT, AIRNETEXTFAN, AIRNETEXTFLOW, and AIRNETHERV).

Units	Legal Range	Default	Required	Variability
	choices above	none	No	constant

izAFCat=choice

Choice indicating air flow category used only for recording air flow results to an AFMETER. izAFCat has no effect for non-AIRNET IZXFERs. izAFCat is not used unless the associated ZONE(s) specify znAFMtr.

Choices are:

InfilEx	Infiltration from ambient
VentEx	Natural ventilation from ambient
FanEx	Forced ventilation from ambient
InfilIz	Interzone infiltration
VentIz	Interzone natural ventilation
FanIz	Interzone forced ventilation
DuctLk	Duct leakage
HVAC	HVAC air

Default values for izAFCat are generally adequate except that natural ventilation IZXFERs are by default categorized as infiltration. It is thus recommended that izAfCat be omitted except that ventilation IZXFERs (e.g. representing openable windows) should include izAfCat=VentEx (or VentIz).

Units	Legal Range	Default	Required	Variability
	choices above	derived from IZXFER characteristics	No	constant

izZn1=znName

Name of primary zone. Flow rates \(>\) 0 are into the primary zone.

Units	Legal Range	Default	Required	Variability
	name of a ZONE	none	Yes	constant

izZn2=znName

Name of secondary zone.

Units	Legal Range	Default	Required	Variability
	name of a ZONE	none	required unless constant izNVType = AIRNETEXT, AIRNETEXTFAN, AIRNETEXTFLOW, or AIRNETHERV	constant

izDOAS=oaName

Name of DOAS where air is supplied from (izVfMin > 0), or exhausting to (izVfMin < 0).

Units	Legal Range	Default	Required	Variability
–	name of a DOAS	–	when izNVType = AIRNETDOAS	constant

izLinkedFlowMult=float

Specifies a multiplier applied to air flow to/from any associated DOAS. This supports use of a single modeled zone to represent multiple actual zones while preserving the total DOAS air flow and energy consumption.

For example, consider a DOAS-linked IZXFER with izVfMin = 100 and izLinkedFlowMult = 5. The zone specified by izZn1 receives 100 cfm while the DOAS specified by izDOAS is modeled as if the supply flow is 500 cfm. Thus the DOAS behavior (fan energy use etc.) approximates that of a DOAS serving 5 zones, but only one zone is simulated.

Note izLinkedFlowMult has no effect on the air flow to or from the zone specified by izZn1.

Units	Legal Range	Default	Required	Variability
–	x \(\gt\) 0	1	No	constant

Give izHConst for a conductive transfer between zones. Give izNVType other than NONE and the following variables for a convective (air) transfer between the zones or between a zone and outdoors. Both may be given if desired. Not known to work properly as of July 2011

izHConst=float

Conductance between zones.

Units	Legal Range	Default	Required	Variability
Btu/oF	x \(\ge\) 0	0	No	hourly

izALo=float

Area of low or only vent (typically VentOff)

Units	Legal Range	Default	Required	Variability
ft2	x \(\ge\) 0	0	No	hourly

izAHi=float

Additional vent area (high vent or VentOn). If used in AIRNET, izAHi > izALo typically but this is not required.

Units	Legal Range	Default	Required	Variability
ft2	x \(\ge\) 0	izALo	No	hourly

izTEx=float

Alternative exterior air dry bulb temperature for this vent. Allowed only with izNVTypes that use outdoor air (AIRNETEXT, AIRNETEXTFAN, AIRNETEXTFLOW, and AIRNETHERV). If given, izTEx overrides the outdoor dry-bulb temperature read from the weather file or derived from design conditions.

Caution: izTEx is not checked for reasonableness.

One use of izTEx is in representation of leaks in surfaces adjacent to zones not being simulated. “Pseudo-interior” surface leakage can be created as follows (where “Z1” is the name of the leak’s zone and izALo and izHD are set to appropriate values) –

 IZXFER RLF izNVTYPE=AirNetExt izZN1="Z1" izALo=.1 izHD=10  izTEx=@zone["Z1"].tzls izWEx=@zone["Z1"].wzls

This will allow Z1’s pressure to be realistic without inducing thermal loads that would occur if the leak source had outdoor conditions.

Units	Legal Range	Default	Required	Variability
oF		Outdoor dry-bulb	No	subhourly

izWEx=float

Alternative exterior air humidity ratio seen by this vent. Allowed only with izNVTypes that use outdoor air (AIRNETEXT, AIRNETEXTFAN, AIRNETEXTFLOW, and AIRNETHERV). If given, izWEx overrides the outdoor humidity ratio derived from weather file data or design conditions.

Caution: izWEx is not checked against saturation – there is no verification that the value provided is physically possible.

See izTEx example just above.

Units	Legal Range	Default	Required	Variability
	\(\gt\) 0	Outdoor humidity ratio	No	subhourly

izWindSpeed=float

Alternative windspeed seen by this vent. Allowed only with izNVTypes that use outdoor air (AIRNETEXT, AIRNETEXTFAN, AIRNETEXTFLOW, and AIRNETHERV). If given, izWindSpeed overrides the windspeed read from the weather file or derived from design conditions.

No adjustments such as TOP windF or ZONE znWindFLkg are applied to izWindSpeed when it is used in derivation of wind-driven air flow.

Note that izCpr must be non-0 for izWindSpeed to have any effect.

Units	Legal Range	Default	Required	Variability
mph	\(\ge\) 0	Zone adjusted windspeed	No	subhourly

izL1=float

Length or width of AIRNETHORIZ opening.

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	none	if izNVType = AIRNETHORIZ	constant

izL2=float

Width or length of AIRNETHORIZ opening.

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	none	if izNVType = AIRNETHORIZ	constant

izStairAngle=float

Stairway angle for AIRNETHORIZ opening. Use 90 for an open hole. Note that 0 prevents flow.

Units	Legal Range	Default	Required	Variability
o degrees	x \(>\) 0	34	No	constant

izHD=float

Vent center-to-center height difference (for TWOWAY) or vent height above nominal 0 level (for AirNet types)

Units	Legal Range	Default	Required	Variability
ft		0	No	constant

izNVEff=float

Vent discharge coefficient.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.8	No	constant

izfanVfDs=float

Fan design or rated flow at rated pressure. For AIRNETHERV, this is the net air flow into the zone, gross flow at the fan is derived using izEATR (see below).

Units	Legal Range	Default	Required	Variability
cfm	x \(\ge\) 0	0 (no fan)	If fan present	constant

izCpr=float

Wind pressure coefficient (for AIRNETEXT).

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	0	No	constant

izExp=float

Opening exponent (for AIRNETEXT).

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.5	No	constant

izVfMin=float

Minimum volume flow rate (VentOff mode).

Units	Legal Range	Default	Required	Variability
cfm	x \(\ge\) 0	izfanVfDs	No	subhourly

izVfMax=float

Maximum volume flow rate (VentOn mode)

Units	Legal Range	Default	Required	Variability
cfm	x \(\ge\) 0	izVfMin	No	subhourly

izASEF=float

Apparent sensible effectiveness for AIRNETHERV ventilator. ASEF is a commonly-reported HERV rating and is calculated as (supplyT - sourceT) / (returnT - sourceT). This formulation includes fan heat (in supplyT), hence the term “apparent”. Ignored if izSRE is given. CSE does not HRV exhaust-side condensation, so this model is approximate.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0	No	subhourly

izSRE=float

Sensible recovery efficiency (SRE) for AIRNETHERV ventilator. Used as the sensible effectiveness in calculation of the supply air temperature. Note that values of SRE greater than approximately 0.6 imply exhaust-side condensation under HVI rating conditions. CSE does not adjust for these effects. High values of izSRE will produce unrealistic results under mild outdoor conditions and/or dry indoor conditions.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0	No	subhourly

izASRE=float

Adjusted sensible recovery efficiency (ASRE) for AIRNETHERV ventilator. The difference izASRE - izSRE is used to calculate fan heat added to the supply air stream. See izSRE notes. No effect when izSRE is 0.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) izSRE	0	No	subhourly

izEATR=float

Exhaust air transfer ratio for AIRNETHERV ventilator. NetFlow = (1 - EATR)*(grossFlow).

Units	Legal Range	Default	Required	Variability
cfm	0 \(\le\) x \(\le\) 1	0	No	subhourly

izLEF=float

Latent heat recovery effectiveness for AIRNETHERV ventilator. The default value (0) results in sensible-only heat recovery.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0	No	subhourly

izRVFanHeatF=float

Fraction of fan heat added to supply air stream for AIRNETHERV ventilator. Used only when when izSRE is 0 (that is, when izASEF specifies the sensible effectiveness).

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0	No	subhourly

izVfExhRat=float

Exhaust volume flow ratio for AIRNETHERV ventilator = (exhaust flow) / (supply flow). Any value other than 1 indicates unbalanced flow that effects the zone pressure.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1 (balanced)	No	constant

izfanPress=float

Design or rated fan pressure.

Units	Legal Range	Default	Required	Variability
inches H2O	x \(>\) 0	0.3	No	constant

Only one of izfanElecPwr, izfanEff, and izfanShaftBhp may be given: together with izfanVfDs and izfanPress, any one is sufficient for CSE to determine the others and to compute the fan heat contribution to the air stream.

izfanElecPwr=float

Fan input power per unit air flow (at design flow and pressure).

Units	Legal Range	Default	Required	Variability
W/cfm	x \(>\) 0	derived from izfanEff and izfanShaftBhp	If izfanEff and izfanShaftBhp not present	constant

izfanEff=float

Fan efficiency at design flow and pressure, as a fraction.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	derived from izfanShaftBhp if given, else 0.08	No	constant

izfanShaftBhp=float

Fan shaft brake horsepower at design flow and pressure.

Units	Legal Range	Default	Required	Variability
bhp	x \(>\) 0	derived from izfanEff.	No	constant

izfanCurvePy=\(k_0\), \(k_1\), \(k_2\), \(k_3\), \(x_0\)

\(k_0\) through \(k_3\) are the coefficients of a cubic polynomial for the curve relating fan relative energy consumption to relative air flow above the minimum flow \(x_0\). Up to five floats may be given, separated by commas. 0 is used for any omitted trailing values. The values are used as follows:

\[z = k_0 + k_1 \cdot (x - x_0)| + k_2 \cdot (x - x_0)|^2 + k_3 \cdot (x - x_0)|^3\]

where:

• \(x\) is the relative fan air flow (as fraction of izfanVfDs; 0 \(\le\) \(x\) \(\le\) 1);
• \(x_0\) is the minimum relative air flow (default 0);
• \((x - x_0)|\) is the “positive difference”, i.e. \((x - x_0)\) if \(x > x_0\); else 0;
• \(z\) is the relative energy consumption.

If \(z\) is not 1.0 for \(x\) = 1.0, a warning message is displayed and the coefficients are normalized by dividing by the polynomial’s value for \(x\) = 1.0.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	0, 1, 0, 0, 0 (linear)	No	constant

izFanMtr=mtrName

Name of meter, if any, to record energy used by supply fan. End use category used is specified by izFanEndUse (next).

Units	Legal Range	Default	Required	Variability
	name of a METER	not recorded	No	constant

izFanEndUse=choice

End use to which fan energy is recorded (in METER specified by izFanMtr). See METER for available end use choices.

Units	Legal Range	Default	Required	Variability
	end use choice	Fan	No	constant

endIZXFER

Optionally indicates the end of the interzone transfer definition.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @izXfer

4.24 DOAS

DOAS (Dedicated Outdoor Air System) provides centralized supply and/or exhuast ventilation air to IZXFER objects with the izNVType = AIRNETDOAS. The supply air may be preconditioned using heat recovery and/or tempering coils.

oaName

Name of DOAS.

4.24.1 DOAS Supply Fan Data Members

oaSupFanVfDs=float

Supply fan design or rated flow at rated pressure.

Units	Legal Range	Default	Required	Variability
cfm	x \(\ge\) 0	Sum of referencing IZXFER supply flows	No	constant

oaSupFanPress=float

Design or rated fan pressure.

Units	Legal Range	Default	Required	Variability
inches H2O	x \(>\) 0	0.3	No	constant

Only one of oaSupFanElecPwr, oaSupFanEff, and oaSupFanShaftBhp may be given.

oaSupFanElecPwr=float

Fan input power per unit air flow (at design flow and pressure).

Units	Legal Range	Default	Required	Variability
W/cfm	x \(>\) 0	derived from oaSupFanEff and oaSupFanShaftBhp	If oaSupFanEff and oaSupFanShaftBhp not present	constant

oaSupFanEff=float

Fan efficiency at design flow and pressure, as a fraction.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	derived from oaSupFanShaftBhp if given, else 0.08	No	constant

oaSupFanShaftBhp=float

Fan shaft brake horsepower at design flow and pressure.

Units	Legal Range	Default	Required	Variability
bhp	x \(>\) 0	derived from oaSupFanEff.	No	constant

oaSupFanCurvePy=\(k_0\), \(k_1\), \(k_2\), \(k_3\), \(x_0\)

\(k_0\) through \(k_3\) are the coefficients of a cubic polynomial for the curve relating fan relative energy consumption to relative air flow above the minimum flow \(x_0\). Up to five floats may be given, separated by commas. 0 is used for any omitted trailing values. The values are used as follows:

\[z = k_0 + k_1 \cdot (x - x_0)| + k_2 \cdot (x - x_0)|^2 + k_3 \cdot (x - x_0)|^3\]

where:

• \(x\) is the relative fan air flow (as fraction of oaSupFanVfDs; 0 \(\le\) \(x\) \(\le\) 1);
• \(x_0\) is the minimum relative air flow (default 0);
• \((x - x_0)|\) is the “positive difference”, i.e. \((x - x_0)\) if \(x > x_0\); else 0;
• \(z\) is the relative energy consumption.

If \(z\) is not 1.0 for \(x\) = 1.0, a warning message is displayed and the coefficients are normalized by dividing by the polynomial’s value for \(x\) = 1.0.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	0, 1, 0, 0, 0 (linear)	No	constant

oaSupFanMtr=mtrName

Name of meter, if any, to record energy used by supply fan. End use category used is specified by oaSupFanEndUse (next).

Units	Legal Range	Default	Required	Variability
	name of a METER	not recorded	No	constant

oaSupFanEndUse=choice

End use to which fan energy is recorded (in METER specified by oaSupFanMtr). See METER for available end use choices.

Units	Legal Range	Default	Required	Variability
	end use choice	Fan	No	constant

oaTEx=float

Alternative supply fan source air dry bulb temperature. If given, oaTEx overrides the outdoor dry-bulb temperature read from the weather file or derived from design conditions.

Caution: oaTEx is not checked for reasonableness.

Units	Legal Range	Default	Required	Variability
oF		Outdoor dry-bulb	No	subhourly

oaWEx=float

Alternative supply fan source air air humidity ratio. If given, oaWEx overrides the outdoor humidity ratio derived from weather file data or design conditions.

Caution: oaWEx is not checked against saturation – there is no verification that the value provided is physically possible.

Units	Legal Range	Default	Required	Variability
	\(\gt\) 0	Outdoor humidity ratio	No	subhourly

4.24.2 DOAS Exhaust Fan Data Members

oaExhFanVfDs=float

Exhaust fan design or rated flow at rated pressure.

Units	Legal Range	Default	Required	Variability
cfm	x \(\ge\) 0	Sum of referencing IZXFER exhaust flows	No	constant

oaExhFanPress=float

Design or rated fan pressure.

Units	Legal Range	Default	Required	Variability
inches H2O	x \(>\) 0	0.3	No	constant

Only one of oaExhFanElecPwr, oaExhFanEff, and oaExhFanShaftBhp may be given.

oaExhFanElecPwr=float

Fan input power per unit air flow (at design flow and pressure).

Units	Legal Range	Default	Required	Variability
W/cfm	x \(>\) 0	derived from oaExhFanEff and oaExhFanShaftBhp	If oaExhFanEff and oaExhFanShaftBhp not present	constant

oaExhFanEff=float

Fan efficiency at design flow and pressure, as a fraction.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	derived from oaExhFanShaftBhp if given, else 0.08	No	constant

oaExhFanShaftBhp=float

Fan shaft brake horsepower at design flow and pressure.

Units	Legal Range	Default	Required	Variability
bhp	x \(>\) 0	derived from oaExhFanEff.	No	constant

oaExhFanCurvePy=\(k_0\), \(k_1\), \(k_2\), \(k_3\), \(x_0\)

\(k_0\) through \(k_3\) are the coefficients of a cubic polynomial for the curve relating fan relative energy consumption to relative air flow above the minimum flow \(x_0\). Up to five floats may be given, separated by commas. 0 is used for any omitted trailing values. The values are used as follows:

\[z = k_0 + k_1 \cdot (x - x_0)| + k_2 \cdot (x - x_0)|^2 + k_3 \cdot (x - x_0)|^3\]

where:

• \(x\) is the relative fan air flow (as fraction of oaExhFanVfDs; 0 \(\le\) \(x\) \(\le\) 1);
• \(x_0\) is the minimum relative air flow (default 0);
• \((x - x_0)|\) is the “positive difference”, i.e. \((x - x_0)\) if \(x > x_0\); else 0;
• \(z\) is the relative energy consumption.

If \(z\) is not 1.0 for \(x\) = 1.0, a warning message is displayed and the coefficients are normalized by dividing by the polynomial’s value for \(x\) = 1.0.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	0, 1, 0, 0, 0 (linear)	No	constant

oaExhFanMtr=mtrName

Name of meter, if any, to record energy used by exhaust fan. End use category used is specified by oaExhFanEndUse (next).

Units	Legal Range	Default	Required	Variability
	name of a METER	not recorded	No	constant

oaExhFanEndUse=choice

End use to which fan energy is recorded (in METER specified by oaExhFanMtr). See METER for available end use choices.

Units	Legal Range	Default	Required	Variability
	end use choice	Fan	No	constant

4.24.3 DOAS Tempering Coils Data Members

oaSupTH=float

Heating setpoint for tempering and/or heat exchanger bypass.

Units	Legal Range	Default	Required	Variability
oF	–	68	No	subhourly

oaEIRH=float

Energy Input Ratio of the heating coil. This is the inverse of the coil efficiency or COP. A value of zero indicates that the coil does not use energy (e.g., hot water coils). Specifying input triggers the modeling of a heating coil.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	0	when modeling heating coil	subhourly

oaCoilHMtr=mtrName

Name of meter, if any, to record energy used by the heating coil.

Units	Legal Range	Default	Required	Variability
	name of a METER	not recorded	No	constant

oaSupTC=float

Cooling setpoint for tempering and/or heat exchanger bypass.

Units	Legal Range	Default	Required	Variability
oF	–	68	No	subhourly

oaEIRC=float

Energy Input Ratio of the cooling coil. This is the inverse of the coil efficiency or COP. A value of zero indicates that the coil does not use energy (e.g., chilled water coils). Specifying input triggers the modeling of a cooling coil.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	0	when modeling cooling coil	subhourly

oaSHRtarget=float

Sensible Heat Ratio of the cooling coil. If the required sensible capacity of the coil and the entered SHR do not produce a valid psychrometric state, the SHR is adjusted and reported through the SHR probe.

Units	Legal Range	Default	Required	Variability
	x \(\gt\) 0	1.0	No	subhourly

oaCoilCMtr=mtrName

Name of meter, if any, to record energy used by the cooling coil.

Units	Legal Range	Default	Required	Variability
	name of a METER	not recorded	No	constant

oaLoadMtr=ldMtrName

Name of load meter, if any, to record load met by the heating coil or cooling coil.

Units	Legal Range	Default	Required	Variability
	name of a LOADMETER	not recorded	No	constant

4.24.4 DOAS Heat Recovery Data Members

oaHXVfDs=float

Heat exchanger design or rated flow.

Units	Legal Range	Default	Required	Variability
cfm	x \(\gt\) 0	Average of supply and exhaust fan design flows	No	constant

oaHXf2=float

Heat exchanger flow fraction (of design flow) used for second set of effectivenesses.

Units	Legal Range	Default	Required	Variability
	0 \(\lt\) x \(\lt\) 1.0	0.75	No	constant

oaHXSenEffHDs=float

Heat exchanger sensible effectiveness in heating mode at the design flow rate. Specifying input triggers modeling of heat recovery.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1.0	–	when modeling heat recovery	constant

oaHXSenEffHf2=float

Heat exchanger sensible effectiveness in heating mode at the second flow rate (oaHXf2).

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1.0	0	No	constant

oaHXLatEffHDs=float

Heat exchanger latent effectiveness in heating mode at the design flow rate.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1.0	0	No	constant

oaHXLatEffHf2=float

Heat exchanger latent effectiveness in heating mode at the second flow rate (oaHXf2).

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1.0	0	No	constant

oaHXSenEffCDs=float

Heat exchanger sensible effectiveness in cooling mode at the design flow rate.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1.0	0	No	constant

oaHXSenEffCf2=float

Heat exchanger sensible effectiveness in cooling mode at the second flow rate (oaHXf2).

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1.0	0	No	constant

oaHXLatEffCDs=float

Heat exchanger latent effectiveness in cooling mode at the design flow rate.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1.0	0	No	constant

oaHXLatEffCf2=float

Heat exchanger latent effectiveness in cooling mode at the second flow rate (oaHXf2).

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1.0	0	No	constant

oaHXBypass=choice

Yes/No choice for enabling heat exchanger bypass. If selected, the outdoor air will bypass the heat exchanger when otherwise the heat exchanger would require more heating or cooling energy to meet the respective setpoints.

Units	Legal Range	Default	Required	Variability
	NO, YES	NO	No	constant

oaHXAuxPwr=float

Auxiliary power required to operate the heat recovery device (e.g., wheel motor, contorls).

Units	Legal Range	Default	Required	Variability
W	x \(\ge\) 0	0	No	subhourly

oaHXAuxMtr=mtrName

Name of meter, if any, to record energy used by auxiliary components of the heat recovery system.

Units	Legal Range	Default	Required	Variability
	name of a METER	not recorded	No	constant

endDOAS

Indicates the end of the DOAS definition. Alternatively, the end of the DOAS definition can be indicated by the declaration of another object or by “END”.

Units	Legal Range	Default	Required	Variability
–	–	N/A	No	constant

Related Probes:

• @doas

4.25 RSYS

RSYS constructs an object representing an air-based residential HVAC system.

rsName

Optional name of HVAC system; give after the word “RSYS” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

rsType=choice

Type of system.

rsType	Description
ACFURNACE	Compressor-based cooling modeled per SEER and EER. Fuel-fired heating. Primary heating input energy is accumulated to end use HTG of meter rsFuelMtr.
ACPMFURNACE	Compressor-based cooling modeled per PERFORMANCEMAP specified in rsPerfMapClg. Fuel-fired heating. Primary heating input energy is accumulated to end use HTG of meter rsFuelMtr.
ACRESISTANCE	Compressor-based cooling and electric (‘strip’) heating. Cooling performance based on SEER and EER. Primary heating input energy is accumulated to end use HTG of meter rsElecMtr.
ACPMRESISTANCE	Cooling based on PERFORMANCEMAP specified in rsPerfMapClg. Primary heating input energy is accumulated to end use HTG of meter rsElecMtr.
ASHP	Air-source heat pump (compressor-based heating and cooling). Primary (compressor) heating input energy is accumulated to end use HTG of meter rsElecMtr. Auxiliary and defrost heating input energy is accumulated to end use HPBU of meter rsElecMtr or meter rsFuelMtr (depending on rsTypeAuxH).
ASHPKGROOM	Packaged room air-source heat pump.
ASHPHYDRONIC	Air-to-water heat pump with hydronic distribution. Compressor performance is approximated using the air-to-air model with adjusted efficiencies.
ASHPPM	Air-to-air heat pump modeled per PERFORMANCMAPs specified via rsPerfMapHtg and rsPerfMapClg.
WSHP	Water-to-air heat pump.
AC	Compressor-based cooling; no heating. Required ratings are SEER and capacity and EER at 95 oF outdoor dry bulb.
ACPM	Compressor-based cooling modeled per PERFORMANCEMAP specified in rsPerfMapClg; no heating.
ACPKGROOM	Packaged compressor-based cooling; no heating. Required ratings are capacity and EER at 95 oF outdoor dry bulb.
FURNACE	Fuel-fired heating. Primary heating input energy is accumulated to end use HTG of meter rsFuelMtr.
RESISTANCE	Electric heating. Primary heating input energy is accumulated to end use HTG of meter rsElecMtr.
ACPKGROOMFURNACE	Packaged room cooling and (separate) furnace heating.
ACPKGROOMRESISTANCE	Packaged room cooling and electric resistance heating.
COMBINEDHEATDHW	Combined heating / DHW. Use rsCHDHWSYS to specify the DHWSYS that provides hot water to the coil in this RSYS. No cooling.
ACCOMBINEDHEATDHW	Compressor-based cooling; COMBINEDHEATDHW heating.
ACPMCOMBINEDHEATDHW	Compressor-based cooling modeled per PERFORMANCEMAP specified in rsPerfMapClg; COMBINEDHEATDHW heating.
FANCOIL	Coil-based heating and cooling. No primary (fuel-using) equipment is modeled. rsLoadMtr, rsHtgLoadMtr, and rsClgLoadMtr are typically used to record loads for linking to an external model.

Units	Legal Range	Default	Required	Variability
	one of above choices	ACFURNACE	No	constant

rsDesc=string

Text description of system, included as documentation in debugging reports such as those triggered by rsGeneratePerfMap=YES

Units	Legal Range	Default	Required	Variability
	string	none	No	constant

rsModeCtrl=choice

Specifies systems heating/cooling availability during simulation.

OFF	System is off (neither heating nor cooling is available)
HEAT	System can heat (assuming rsType can heat)
COOL	System can cool (assuming rsType can cool)
AUTO	System can either heat or cool (assuming rsType compatibility). First request by any zone served by this RSYS determines mode for the current time step.

Units	Legal Range	Default	Required	Variability
	OFF, HEAT, COOL, AUTO	AUTO	No	hourly

rsGeneratePerfMap=choice

Generate performance map(s) for this RSYS. Comma-separated text is written to file PM_[rsName].csv. This is a debugging capability that is not necessarily maintained. The format of the generated csv text file may change and is unrelated to the PERFORMANCEMAP input scheme used via rsPerfMapHtg and rsPerfMapClg.

Units	Legal Range	Default	Required	Variability
	YES, NO	NO	No	constant

rsFanTy=choice

Specifies fan (blower) position relative to primary heating or cooling source (i.e. heat exchanger or heat pump coil for heating and AC coil for cooling). The blower position determines where fan heat is added to the RSYS air stream and thus influences the coil entering air temperature.

Units	Legal Range	Default	Required	Variability
	BLOWTHRU, DRAWTHRU	BLOWTHRU	No	constant

rsFanMotTy=choice

Specifies type of motor driving the fan (blower). This is used in the derivation of the coil-only cooling capacity for the RSYS.

PSC	Permanent split capacitor
BPM	Brushless permanent magnet (aka ECM)

Units	Legal Range	Default	Required	Variability
	PSC, BPM	PSC	No	constant

rsAdjForFanHt=choice

Fan heat adjustment with two options Yes or no. Yes: fanHtRtd derived from rsFanTy and removed from capacity and input values. No: no rated fan heat adjustments.

rsElecMtr=mtrName

Name of METER object, if any, by which system’s electrical energy use is recorded (under appropriate end uses).

Units	Legal Range	Default	Required	Variability
	name of a METER	none	No	constant

rsFuelMtr =mtrName

Name of METER object, if any, by which system’s fuel energy use is recorded (under appropriate end uses).

Units	Legal Range	Default	Required	Variability
	name of a METER	none	No	constant

rsLoadMtr =ldMtrName
rsHtgLoadMtr =ldMtrName
rsClgLoadMtr =ldMtrName

Names of LOADMETER objects, if any, to which the system’s heating and/or cooling loads are recorded. Loads are the gross heating and cooling energy added to (or removed from) the air stream. Fan heat, auxiliary heat, and duct losses are not included in loads values.

rsLoadMtr accumulates both heating (> 0) and cooling (< 0) loads. rsHtgLoadMtr accumulates only heating loads. rsClgLoadMtr accumulates only cooling loads. This arrangement accomodates mixed heating and cooling source configurations. For example, loads can be tracked appropriately in a building that has multiple cooling sources and a single heating source.

rsLoadMtr should not specify the same LOADMETER as rsHtgLoadMtr or rsClgLoadMtr since this would result in double counting.

Units	Legal Range	Default	Required	Variability
	name of a LOADMETER	none	No	constant

rsSrcSideLoadMtr=ldMtrName
rsHtgSrcSideLoadMtr =ldMtrName
rsClgSrcSideLoadMtr =ldMtrName

Name of LOADMETER objects, if any, to which the system’s source-side heat transfers are recorded. For DX systems, this is the outdoor coil heat transfer. For other types, source-side values are the same as the indoor coil loads reported via rsLoadMtr.

rsSrcSideLoadMtr accumulates both heating (> 0) and cooling (< 0) transfers. rsHtgSrcSideLoadMtr accumulates only heating transfers. rsClgSrcSideLoadMtr accumulates only cooling transfers. This arrangement accomodates mixed heating and cooling source configurations.

rsSrcSideLoadMtr should not specify the same LOADMETER as rsHtgSrcSideLoadMtr or rsClgSrcSideLoadMtr since this would result in double counting.

Units	Legal Range	Default	Required	Variability
	Name of a LOADMETER		No	constant

rsCHDHWSYS=dhwsysName

DHWSYS hot water source for this RSYS, required when rsType is COMBINEDHEATDHW or ACCOMBINEDHEATDHW. The specified DHWSYS must include a DHWHEATER of whType=ASHPX or RESISTANCEX.

Units	Legal Range	Default	Required	Variability
	Name of a DHWSYS	none	if combined heat/DHW	constant

rsAFUE=float

Heating Annual Fuel Utilization Efficiency (AFUE).

Units	Legal Range	Default	Required	Variability
	0 \(<\) x \(\le\) 1	0.9 if furnace, 1.0 if resistance	No	constant

rsCapH=float

Heating capacity, used when rsType is ACFURNACE, ACRESISTANCE, FURNACE, WSHP or RESISTANCE.

If rsType=WSHP, rsCapH is at source fluid temperature = 68 ^oF.

Units	Legal Range	Default	Required	Variability
Btu/hr	AUTOSIZE or x \(\ge\) 0	0	No	constant

rsTdDesH=float

Nominal heating temperature rise (across system, not at zone) used during autosizing (when capacity is not yet known) and to derive heating air flow rate from heating capacity.

Units	Legal Range	Default	Required	Variability
oF	x \(>\) 0	30 oF if heat pump else 50 oF	No	constant

rsFxCapH=float

Heating autosizing capacity factor. If AUTOSIZEd, rsCapH or rsCap47 is set to rsFxCapH \(\times\) (peak design-day load). Peak design-day load is the heating capacity that holds zone temperature at the thermostat set point during the last substep of all hours of all design days.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1.4	No	constant

rsFanPwrH=float

Heating operating fan power. For most rsTypes, heating air flow is calculated from heating capacity and rsTdDesH. The default value of rsFanPwrH is .365 W/cfm except 0.273 W/cfm is used when rsType=COMBINEDHEATDHW and rsType=ACCOMBINEDHEATDHW.

Units	Legal Range	Default	Required	Variability
W/cfm	x \(\ge\) 0	see above	No	constant

rsHSPF=float

For rsType=ASHP, Heating Seasonal Performance Factor (HSPF).

Units	Legal Range	Default	Required	Variability
Btu/Wh	x \(>\) 0	none	Yes if rsType=ASHP	constant

rsCap47=float

For rsType=ASHP, rated heating capacity at outdoor dry-bulb temperature = 47 ^oF.

If rsType=ASHP and both rsCapC and rsCap47 are autosized, both are set to the larger consistent value using rsCapRat9547 (after application of rsFxCapH and rsFxCapC).

Units	Legal Range	Default	Required	Variability
Btu/Wh	AUTOSIZE or x \(>\) 0	Calculated from rsCapC	No	constant

rsCap35=float

For rsType=ASHP, rated heating capacity at outdoor dry-bulb temperature = 35 ^oF. rsCap35 typically reflects reduced capacity due to reverse (cooling) heat pump operation for defrost.

Units	Legal Range	Default	Required	Variability
Btu/Wh	x \(>\) 0	Calculated from rsCap47 and rsCap17	No	constant

rsCap17=float

For rsType=ASHP, rated heating capacity at outdoor dry-bulb temperature = 17 ^oF.

Units	Legal Range	Default	Required	Variability
Btu/Wh	x \(>\) 0	Calculated from rsCap47	No	constant

rsCOP95=float

For rsType=ASHP, rated heating coefficient of performance at outdoor dry-bulb temperature = 95 ^oF.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	Calculated from rsCap95	No	constant

rsCOP47=float

For rsType=ASHP, rated heating coefficient of performance at outdoor dry-bulb temperature = 47 ^oF. For rsType=WSHP, rated heating coefficient of performance at source fluid temperature = 68 ^oF.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	Estimated from rsHSPF, rsCap47, and rsCap17	No	constant

rsCOP35=float

For rsType=ASHP, rated heating coefficient of performance at outdoor dry-bulb temperature = 35 ^oF.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	Calculated from rsCap35, rsCap47, rsCap17, rsCOP47, and rsCOP17	No	constant

rsCOP17=float

For rsType=ASHP, rated heating coefficient of performance at outdoor dry-bulb temperature = 17 ^oF.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	Calculated from rsHSPF, rsCap47, and rsCap17	No	constant

rsCapRat1747=float

Ratio of rsCAP17 over rsCAP47.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	Based on HSPF or other correlations	No	Start of a run

rsCapRat9547=float

Ratio of rsCAP95 to rsCAP47. This ratio is used for inter-defaulting rsCap47 and rsCapC such that they have consistent values as is required given that a heat pump is a single device. If not given, rsCapRat9547 is determined during calculations using the relationship cap95 = 0.98 * cap47 + 180 (derived via correlation of capacities of a set of real units).

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	See above	No	constant

rsCapRatCH=float

For WSHP only: ratio of rsCapC to rsCapH. Used to derive capacity during autosizing or when only one capacity is specified.

Units	Legal Range	Default	Required	Variability
	.3 \(\leq\) x \(<\) 2	0.8	No	Start of a run

rsPerfMapHtg=performanceMapName

Specifies the heating performance PERFORMANCEMAP for RSYSs having rsType=ASHPPM. The PERFORMANCEMAP must have grid variables outdoor drybulb and compressor speed (in that order) and lookup values of net capacity ratios and COP. See example in PERFORMANCEMAP.

Units	Legal Range	Default	Required	Variability
	Name of a PERFORMANCEMAP		if rsType specifies a performance map model	Start of a run

rsPerfMapClg=performanceMapName

Specifies the cooling performance PERFORMANCEMAP for RSYSs having rsType=ASHPPM, ACPM, ACPMFURNACE, ACPMRESISTANCE, or ACPMCOMBINEDHEATDHW. The PERFORMANCEMAP must have grid variables outdoor drybulb and compressor speed (in that order) and lookup values of net capacity ratios and COP. See example in PERFORMANCEMAP.

Units	Legal Range	Default	Required	Variability
	Name of a PERFORMANCEMAP		if rsType specifies a performance map model	Start of a run

rsTypeAuxH=choice

For rsType=ASHP, type of auxiliary heat. Auxiliary heating is used when heatpump capacity is insufficient to maintain zone temperature and during reverse-cycle defrost operation (if rsDefrostModel=REVCYCLEAUX). If rsTypeAuxH=Furnace, energy use for auxiliary heat is accumulated to end use HPBU of meter rsFuelMtr (if specified). If rsTypeAuxH=Resistance, energy use for auxiliary heat is accumulated to end use HPBU of meter rsElecMtr (if specified).

Choice	Description
NONE	No auxiliary heat
RESISTANCE	Electric resistance (aka strip heat)
FURNACE	Fuel-fired

Units	Legal Range	Default	Required	Variability
	See table above	RESISTANCE	No	constant

rsCtrlAuxH=choice

For rsType=ASHP, type of auxiliary heating control.

Choice	Description
LOCKOUT	Compressor locked out if any auxiliary heating control
CYCLE	Compressor runs continuously and auxiliary cycles
ALTERNATE	Alternates between compressor and auxiliary

Units	Legal Range	Default	Required	Variability
	See table above	ALTERNATE if rsTypeAuxH=FURNACE else CYCLE	No	Start of a run

rsCapAuxH=float

For rsType=ASHP, auxiliary heating capacity. If AUTOSIZEd, rsCapAuxH is set to the peak heating load evaluated at the heating design temperature (Top.heatDsTDbO).

Units	Legal Range	Default	Required	Variability
Btu/hr	AUTOSIZE or x \(\ge\) 0	0	No	constant

rsAFUEAuxH=float

For rsType=ASHP, auxiliary heat annualized fuel utilization efficiency.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.9 if rsTypeAuxH=FURNACE else 1	No	constant

rsDefrostModel=choice

Selects modeling options for ASHP outdoor coil defrosting when 17 ^oF < TDbO < 45 ^oF. In this temperature range, heating capacity and/or efficiency are typically reduced due to frost accumulation on the outdoor coil.

NONE	Defrost is not modeled. When 17 oF < TDbO < 45 oF, capacity and efficiency are determined by interpolation using unmodified 17 oF and 47 oF data.
REVCYCLE	Reverse compressor (cooling) operation. Net capacity and efficiency is derived from rsCap17/rsCOP17 and rsCap35/rsCOP35 using linear interpolation. Auxiliary heat is not modeled.
REVCYCLEAUX	Reverse compressor (cooling) operation with provision of sufficient auxiliary heat to make up the loss of heating capacity. Auxiliary heating is typically used to prevent cold air delivery to zones during the defrost cycle.

Units	Legal Range	Default	Required	Variability
	one of above choices	REVCYCLEAUX	No	constant

rsSHRtarget=float

Nominal target for sensible heat ratio (for fancoil).

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.7	No	subhour

rsFxCapAuxH=float

Auxiliary heating autosizing capacity factor. If AUTOSIZEd, rsCapAuxH is set to rsFxCapAuxH \(\times\) (peak design-day load). Peak design-day load is the heating capacity that holds zone temperature at the thermostat set point during the last substep of all hours of all design days.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

rsSEER=float

Cooling rated Seasonal Energy Efficiency Ratio (SEER).

Units	Legal Range	Default	Required	Variability
Btu/Wh	x \(>\) 0	none	Yes	constant

rsEER=float

Cooling Energy Efficiency Ratio (EER) at standard AHRI rating conditions (outdoor drybulb of 95 ^oF and entering air at 80 ^oF drybulb and 67 ^oF wetbulb). For rsType=WSHP, rated EER at fluid source temperature = 86 ^oF.

Units	Legal Range	Default	Required	Variability
Btu/Wh	x \(>\) 0	Estimated from SEER unless WSHP	Yes for WSHP else No	constant

rsCapC=float

Net cooling capacity at standard rating conditions (outdoor drybulb temperature = 95 ^oF for air source or fluid source temperature = 86 ^oF for water source).

If rsType=ASHP and both rsCapC and rsCap47 are autosized, both are set to the larger consistent value using rsCapRat9547 (after application of rsFxCapH and rsFxCapC).

If rsType=WSHP and both rsCapC and rsCapH are autosized, both are set to the larger consistent value using rsCapRatCH (after application of rsFxCapH and rsFxCapC).

Units	Legal Range	Default	Required	Variability
Btu/hr	AUTOSIZE or x \(\le\) 0 (x \(>\) 0 coverted to \(<\) 0)	none	Yes if rsType includes cooling	constant

rsTdDesC=float

Nominal cooling temperature fall (across system, not zone) used during autosizing (when capacity is not yet known).

Units	Legal Range	Default	Required	Variability
oF	x \(<\) 0	-25	No	constant

rsFxCapC=float

Cooling autosizing capacity factor. rsCapC is set to rsFxCapC \(\times\) (peak design-day load). Peak design-day load is the cooling capacity that holds zone temperature at the thermostat set point during the last substep of all hours of all design days.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1.4	No	constant

rsFChg=float

Cooling compressor capacity factor. The gross cooling capacity is adjusted by the factor rsFChg as specified by California Title 24 procedures.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1 (no effect)	No	constant

rsVFPerTon=float

Standard air volumetric flow rate per nominal ton of cooling capacity.

Units	Legal Range	Default	Required	Variability
cfm/ton	150 \(\le\) x \(\le\) 500	350	No	constant

rsFanPwrC=float

Cooling fan power.

Units	Legal Range	Default	Required	Variability
W/cfm	x \(\ge\) 0	0.365	No	constant

rsASHPLockOutT=float

Source air dry-bulb temperature below which the air source heat pump compressor does not operate.

Units	Legal Range	Default	Required	Variability
oF		(no lockout)	No	hourly

rsCdH=float

Heating cyclic degradation coefficient, valid only for compressor-based heating (heat pumps).

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 0.5	ASHPHYDRONIC: 0.25 ASHP: derived from rsHSPF	No	hourly

rsCdC=float

Cooling cyclic degradation coefficient, valid for configurations having compressor-based cooling.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 0.5	0	No	hourly

rsFEffH=float

Heating efficiency factor. At each time step, the heating efficiency is multiplied by rsFEffH.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	subhourly

rsFEffAuxHBackup=float

Backup auxiliary heating efficiency factor. At each time step, the backup heating efficiency is multiplied by rsFEffAuxHBackup. Backup auxiliary heating is typically provided by electric resistance “strip heat” but may be provided by a furnace (see rsTypeAuxH). If rsTypeAuxH is not “none”, backup heat operates when air source heat pump compressor capacity is insufficient to meet heating load. See also rsFEffAuxHDefrost.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	subhourly

rsFEffAuxHDefrost=float

Defrost auxiliary heating efficiency factor. At each time step, the defrost auxiliary heating efficiency is multiplied by rsFEffAuxHDefrost. Defrost auxiliary heating is typically provided by electric resistance “strip heat” but may be provided by a furnace (see rsTypeAuxH). If rsDefrostModel=REVCYCLEAUX, defrost auxiliary heat operates during air source heat pump defrost mode. Since defrost and backup heating are generally provided by the same equipment, rsFEffAuxHDefrost and rsFEffAuxHBackup are usually set to the same value, but separate inputs are available for special cases.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	subhourly

rsFEffC=float

Cooling efficiency factor. At each time step, the cooling efficiency is multiplied by rsEffC.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	subhourly

rsCapNomH=float

Heating nominal capacity. Provides type-independent probe source for RSYS heating capacity. Daily variability is specified to support value changes during AUTOSIZEing. Values set via input are typically constant.

Units	Legal Range	Default	Required	Variability
Btu/hr	x \(\ge\) 0	no heating: 0 heat pump: rsCap47 (input or AUTOSIZEd) other: rsCapH (input or AUTOSIZEd)	No	daily

rsCapNomC=float

Cooling nominal capacity. Provides type-independent probe source for RSYS cooling capacity. Daily variability is specified to support value changes during AUTOSIZEing. Values set via input are typically constant.

Units	Legal Range	Default	Required	Variability
Btu/hr	x \(\ge\) 0	no cooling: 0 other: rsCap95 (input or AUTOSIZEd)	No	daily

rsDSEH=float

Heating distribution system efficiency. If given, (1-rsDSEH) of RSYS heating output is discarded. Cannot be combined with more detailed DUCTSEG model.

Units	Legal Range	Default	Required	Variability
	0 < x < 1	(use DUCTSEG model)	No	hourly

rsDSEC=float

Cooling distribution system efficiency. If given, (1-rsDSEC) of RSYS cooling output is discarded. Cannot be combined with more detailed DUCTSEG model.

Units	Legal Range	Default	Required	Variability
	0 < x < 1	(use DUCTSEG model)	No	hourly

rsOAVType=choice

Type of central fan integrated (CFI) outside air ventilation (OAV) included in this RSYS. OAV systems use the central system fan to circulate outdoor air (e.g. for night ventilation).

OAV cannot operate simultaneously with whole building ventilation (operable windows, whole house fans, etc.). Availability of ventilation modes is controlled on an hourly basis via Top ventAvail.

NONE	No CFI ventilation capabilities
FIXED	Fixed-flow CFI (aka SmartVent). The specified rsOAVVfDs is used whenever the RSYS operates in OAV mode.
VARIABLE	Variable-flow CFI (aka NightBreeze). Flow rate is determined at midnight based on prior day’s average dry-bulb temperature according to a control algorithm defined by the NightBreeze vendor.

Units	Legal Range	Default	Required	Variability
	NONE, FIXED, VARIABLE	none	No	constant

rsOAVVfDs=float

Design air volume flow rate when RSYS is operating in OAV mode.

Units	Legal Range	Default	Required	Variability
cfm	x \(\ge\) 0	none	if rsOAVType $ e$ NONE	constant

rsOAVVfMinF=float

Minimum air volume flow rate fraction when RSYS is operating in OAV mode. When rsOAVType=VARIABLE, air flow rate is constrained to rsOAVVfMinF * rsOAVVfDs or greater.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.2	No	constant

rsOAVFanPwr=float

RSYS OAV-mode fan power.

Units	Legal Range	Default	Required	Variability
W/cfm	0 < x \(\le\) 5	per rsOAVTYPE FIXED: rsFanPwrC VARIABLE: NightBreeze vendor curve based on rsOAVvfDs	No	constant

rsOAVTDbInlet=float

OAV inlet (source) air temperature. Supply air temperature at the zone is generally higher due to fan heat. Duct losses, if any, also alter the supply air temperature.

Units	Legal Range	Default	Required	Variability
oF	x \(\ge\) 0	Dry-bulb temperature from weather file	No	hourly

rsOAVTdiff=float

OAV temperature differential. When operating in OAV mode, the zone set point temperature is max( znTD, inletT+rsOAVTdiff). Small values can result in inadvertent zone heating, due to fan heat.

Units	Legal Range	Default	Required	Variability
oF	x \(>\) 0	5 oF	No	hourly

rsOAVReliefZn=znName

Name of zone to which relief air is directed during RSYS OAV operation, typically an attic zone. Relief air flow is included in the target zone’s pressure and thermal balance.

Units	Legal Range	Default	Required	Variability
	name of ZONE	none	if rsOAVType $ e$ NONE	constant

rsParElec=float

Parasitic electrical power. rsParElec is unconditionally accumulated to end use AUX of rsElecMtr (if specified) and has no other effect.

Units	Legal Range	Default	Required	Variability
W		0	No	hourly

rsParFuel=float

Parasitic fuel use. rsParFuel is unconditionally accumulated to end use AUX of sFuelMtr (if specified) and has no other effect.

Units	Legal Range	Default	Required	Variability
Btuh		0	No	hourly

rsRhIn=float

Entering air relative humidity (for model testing).

Units	Legal Range	Default	Required	Variability
W/cfm	0 \(\le\) x \(\le\) 1	Derived from entering air state	No	constant

rsTdbOut=float

Air dry-bulb temperature at the outdoor portion of this system.

Units	Legal Range	Default	Required	Variability
oF	x \(\ge\) 0	From weather file	No	hourly

endRSYS

Optionally indicates the end of the RSYS definition.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @rsys
• @RSYSRes (accumulated results)

4.26 DUCTSEG

DUCTSEG defines a duct segment. Each RSYS has at most one return duct segment and at most one supply duct segment. That is, DUCTSEG input may be completely omitted to eliminate duct losses.

dsName

Optional name of duct segment; give after the word “DUCTSEG” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

dsTy=choice

Duct segment type.

Units	Legal Range	Default	Required	Variability
	SUPPLY, RETURN		Yes	constant

The surface area of a DUCTSEG depends on its shape. 0 surface area is legal (leakage only). DUCTSEG shape is modeled either as flat or round –

• dsExArea specified: Flat. Interior and exterior areas are assumed to be equal (duct surfaces are flat and corner effects are neglected).
• dsExArea not specified: Round. Any two of dsInArea, dsDiameter, and dsLength must be given. Insulation thickness is derived from dsInsulR and dsInsulMat and this thickness is used to calculate the exterior surface area. Overall inside-to-outside conductance is also calculated including suitable adjustment for curvature.

dsBranchLen=float

Average branch length.

Units	Legal Range	Default	Required	Variability
ft	x \(>\) 0	-1.0	No	constant

dsBranchCount=integer

Number of branches.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	-1	No	constant

dsBranchCFA=float

Floor area served per branch

Units	Legal Range	Default	Required	Variability
ft2	x \(>\) 0	-1.0	No	constant

dsAirVelDs=float

Specified air velocity design.

Units	Legal Range	Default	Required	Variability
fpm	x \(>\) 0	-1.0	No	constant

dsExArea=float

Duct segment surface area at outside face of insulation for flat duct shape, see above.

Units	Legal Range	Default	Required	Variability
ft2	x \(\ge\) 0	none	No	constant

dsInArea=float

Duct segment inside surface area (at duct wall, duct wall thickness assumed negligible) for round shaped duct.

Units	Legal Range	Default	Required	Variability
ft2	x \(\ge\) 0	Derived from dsDiameter and dsLength	(see above reduct shape)	constant

dsDiameter=float

Duct segment round duct diameter (duct wall thickness assumed negligible)

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	Derived from dsInArea and dsLength	(see above reduct shape)	constant

dsLength=float

Duct segment length.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	Derived from dsInArea and dsDiameter	(see above reduct shape)	constant

dsExCnd=choice

Conditions surrounding duct segment.

Units	Legal Range	Default	Required	Variability
	ADIABATIC, AMBIENT, SPECIFIEDT, ADJZN	ADJZN	No	constant

dsAdjZn=znName

Name of zone surrounding duct segment; used only when dsExCon is ADJZN. Can be the same as a zone served by the RSYS owning the duct segment.

Units	Legal Range	Default	Required	Variability
	name of a ZONE	none	Required when dsExCon = ADJZN	constant

dsEpsLW=float

Exposed (i.e. insulation) outside surface exterior long wave (thermal) emittance.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	0.9	No	constant

dsExT=float

Air dry-bulb temperature surrounding duct segment.

Units	Legal Range	Default	Required	Variability
oF	unrestricted	none	Required if sfExCnd = SPECIFIEDT	hourly

dsInsulR=float

Insulation thermal resistance not including surface conductances. dsInsulR and dsInsulMat are used to calculate insulation thickness (see below). Duct insulation is modeled as a pure conductance (no mass).

Units	Legal Range	Default	Required	Variability
ft2-oF-hr / Btu	x \(\ge\) 0	0	No	constant

dsInsulMat=matName

Name of insulation MATERIAL. The conductivity of this material at 70 ^oF is combined with dsInsulR to derive the duct insulation thickness. If omitted, a typical fiberglass material is assumed having conductivity of 0.025 Btu/hr-ft²-F at 70 ^oF and a conductivity coefficient of .00418 1/F (see MATERIAL). In addition, insulation conductivity is adjusted during the simulation in response its average temperature. As noted with dsInsulR, duct insulation is modeled as pure conductance – MATERIAL matDens and matSpHt are ignored.

Units	Legal Range	Default	Required	Variability
	name of a MATERIAL	fiberglass	No	constant

dsLeakF=float

Duct leakage. Return duct leakage is modeled as if it all occurs at the segment inlet. Supply duct leakage is modeled as if it all occurs at the outlet.

Units	Legal Range	Default	Required	Variability
	0 \(<\) x \(\le\) 1	none	No	constant

dsExH=float

Outside (exposed) surface convection coefficient.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(\ge\) 0	.54	No	subhourly

endDuctSeg

Optionally indicates the end of the DUCTSEG definition.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @ductSeg
• @izXfer (generated as “<Zone Name>-DLkI” for supply or “<Zone Name>-DLkO” for return)

4.27 PERFORMANCEMAP

PERFORMANCEMAP defines a multiple-dimension table of values from which models can derive performance data via interpolation. Subordinate PMGRIDAXIS and PMLOOKUPDATA allow input of performance maps of a range of dimensions and granularity.

Following ASHRAE Standard 205 terminology, sets of “grid” values are the independent variables and sets of “lookup” values are the dependent variables.

The following example defines a 2D map based on grid variables outdoor dry-bulb temperature and (arbitrary) compressor speed. For each grid value combination, lookup values are provided for capacity ratio and COP.

PERFORMANCEMAP "PMClg"

    PMGRIDAXIS "ClgOutdoorDBT" pmGXType="OutdoorDBT" pmGXValues=60,82,95,115 pmGXRefValue=95
    PMGRIDAXIS "ClgSpeed" pmGType="Speed" pmGXValues=1,2,3 pmGXRefValue=2

    // Capacity ratio = net total capacity / net rated total capacity
    PMLOOKUPDATA LUClgCapRat pmLUType = "CapRat" pmLUValues =
      0.48, 1.13, 1.26,   // 60F at min, mid, max speed
      0.42, 1.05, 1.17,   // 82F
      0.39, 1.00, 1.12,   // 95F
      0.34, 0.92, 1.04    // 115F

    // COP = net total COP
    PMLOOKUPDATA LUClgCOP pmLUType = "COP" pmLUValues =
      14.22, 16.44, 15.00,  // 60F at min, mid, max speed
      7.93,  7.59,  6.71,   // 82F
      6.01,  5.58,  4.91,   // 95F
      4.12,  3.82,  3.34    // 115F

endPERFORMANCEMAP

At OutdoorDBT=95 and Speed=2, this performance map would yield CapRat=1.00 and COP=5.58. At other (OutdoorDBT,Speed) combinations, suitable 2D interpolation is performed on each lookup variable. Lookup variables are extrapolated outside of PMGRIDAXIS ranges; adequate axis ranges must be provided to avoid unrealistic extrapolation.

pmName

Name of performance map; given after the word “PERFORMANCEMAP”. Necessary to allow reference from e.g. RSYS.

Units	Legal Range	Default	Required	Variability
	63 characters	none	Yes	constant

endPERFORMANCEMAP

Optionally indicates the end of PERFORMANCEMAP definition. It is good practice to include endPerformanceMap after the associated PMGRIDAXIS and PMLOOKDATA.

Units	Legal Range	Default	Required	Variability
		none	No	constant

4.28 PMGRIDAXIS

Defines grid values for a single dimension of the parent (preceeding) PERFORMANCEMAP.

The order of PMGRIDAXIS commands fixes the order of PMLOOKUPDATA values – later PMGRIDAXIS dimensions vary more quickly (see example above).

pmGXName

Name of grid axis; optionally given after the word “PMGRIDAXIS”. Used in error messages.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

pmGXType=string

Documents the dimension of the axis, for example “OutdoorDBT”, “Speed”, or “AirFlow”.

Units	Legal Range	Default	Required	Variability
	at least 1 char	none	Yes	constant

pmGXValues=float array

1 to 10 comma-separated values specifying the data points of this axis. Must be in strictly ascending order.

Units	Legal Range	Default	Required	Variability
various		none	Yes	constant

pmGXRefValue=float

Defines the reference or nominal value of this PMGRIDAXIS. For example, when defining temperature points for a typical air conditioner, pmGXRefValue=95 might be used, since AC capacity is rated at 95 F.

Units	Legal Range	Default	Required	Variability
same as pmGXValues		none	Yes	constant

endPMGRIDAXIS

Optionally indicates the end of PMGRIDAXIS definition.

Units	Legal Range	Default	Required	Variability
		none	No	constant

4.29 PMLOOKUPDATA

*pmLUName**

Name of lookup data; optionally given after the word “PMLOOKUPDATA”. Used in error messages.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

pmLUType=string

Documents the current lookup value, e.g. “COP” or “CapacityRatio”.

Units	Legal Range	Default	Required	Variability
	at least 1 char	none	Yes	constant

pmLUValues=float array

Comma-separated values specifying the lookup data. The number of values required is the product of the size of all PMGRIDAXISs in the current PEFORMANCEMAP. In the example above, there are 4 OutdoorDBTs and 3 speeds, so 12 values must be provided.

Units	Legal Range	Default	Required	Variability
various		none	Yes	constant

endPMLOOKUPDATA

Optionally indicates the end of PMLOOKUPDATA definition.

Units	Legal Range	Default	Required	Variability
		none	No	constant

4.30 DHWDAYUSE

Defines an object that represents domestic hot water use for a single day. A DHWDAYUSE contains a collection of DHWUSE objects that specify the time, volume, and duration of individual draws. DHWDAYUSEs are referenced by DHWSYS wsDayUse. Unreferenced DHWDAYUSEs are allowed.

DHWDAYUSEs and their child DHWUSEs are used to construct minute-by-minute hot water use schedules in addition to aggregated hourly schedules. The minute-by-minute schedules are used for modeling resistance and heat pump storage water heaters, see DHWHEATER whType=SmallStorage whHeatSrc=ResistanceX or whHeatSrc=ASHPX.

The following illustrates some features of DHWDAYUSE / DHWUSE –

DHWDAYUSE "Sample"
   // 6 AM: 7 min shower, 2 gpm @ 105 F
   DHWUSE whStart=6.0 wuDuration=7 wuFlow=2 wuTemp=105 wuEndUse=Shower wuEventID=1

   // 7 AM: 1 min faucet draw, 100% hot
   DHWUSE whStart=7.0 wuDuration=1 wuFlow=1 wuHotF=1 whEndUse=Faucet wuEventID=2

   // 12:30 PM: dishwasher start, several draws over 70 mins; note common wuEventID
   DHWUSE whStart=12.5 wuDuration=2 wuFlow=2 wuHotF=1 whEndUse=DWashr wuEventID=3
   DHWUSE whStart=12.8 wuDuration=1.5 wuFlow=2 wuHotF=1 whEndUse=DWashr wuEventID=3
   DHWUSE whStart=13.6 wuDuration=3 wuFlow=2 wuHotF=1 whEndUse=DWashr wuEventID=3

   // 7 PM every 2nd day: clothes washer runs
   //   even days: 0 gpm (no draw)
   //   odd days: 3 gpm, 22% hot
   DHWUSE whStart=19 wuDuration=30 wuFlow = ($dayOfYear%2)*3 whEndUse=CWashr whHotF=.22 wuEventID=4

   // 11:54 PM: 20 min bath, 1.5 gpm, 80% hot water
   // Duration spans midnight: draw is wrapped to beginning of *current* day
   //   In this case a 12 M - 12:14 AM draw is modeled -- before (!) the bath start.
   DHWUSE whStart 23.9 wuDuration=20 wuFlow=1.5  wuHotF=.8 whEndUse=Bath wuEventID=99
endDHWDAYUSE

DHWSYS "DHWSYS1"
  ...
  wsDayUse = "Sample"
  ...

During the simulation, DHWUSEs are evaluated each hour. Many DHWUSE values have hourly variability and this allows complicated schemes to be constructed very flexibly. For example:

DHWDAYUSE "HourlyFaucet"
   // Every hour on the half hour: 5 minute, 2 gpm draw
   //   Same as 24 DHWUSEs, one for each hour
   DHWUSE wuStart=$hour+.5 wuDuration=5 wuFlow=2 wuEndUse=Faucet
endDAYUSE

Some DHWUSE configurations involve mixing to specified wuTemp. Hot and cold water arriving at the point of use is assumed to be at DHWSYS wsUseTemp and wsMainsTemp respectively. It is possible to set up situations where wuTemp cannot be achieved (wuTemp > wsUseTemp, for example). Runtime error messages are produced when impossible conditions are detected.

When more than one DHWSYS references the same DHWDAYUSE, DHWUSEs are allocated to DHWSYSs in wuEventID rotation. This procedure divides the water heating load approximately equally while retaining the peak demand of individual events. When detailed information is available about which loads are served by specific systems, separate DHWDAYUSEs should be given.

dhwDayUseName

Object name, given after “DHWDAYUSE”. Required for referencing from DHWSYS.

Units	Legal Range	Default	Required	Variability
	63 characters	none	Yes	constant

wduMult=float

Scale factor applied to all draws in this DHWDAYUSE.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	constant

endDHWDAYUSE

Indicates the end of the DHWDAYUSE definition. endDHWDAYUSE should follow all child DHWUSEs. Alternatively, the end of the meter definition can be indicated by the declaration of another object or by END.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @DHWDayUse

4.31 DHWUSE

Defines a single hot water draw as part of a DHWDAYUSE. See discussion and examples under DHWDAYUSE. As noted there, most DHWUSE values have hourly variability, allowing flexible representation.

wuName

Optional name; give after the word “DHWUSE” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

wuStart=float

The starting time of the hot water draw.

Units	Legal Range	Default	Required	Variability
hr	0 \(\le\) x \(\le\) 24	none	Yes	constant

wuDuration=float

Draw duration. wuDuration = 0 is equivalent to omitting the DHWUSE. Durations that extend beyond midnight are included in the current day.

Units	Legal Range	Default	Required	Variability
min	0 \(\le\) x \(\le\) 1440	0	No	hourly

wuFlow=float

Draw flow rate at the point of use (in other words, the mixed-water flow rate). wuFlow = 0 is equivalent to omitting the DHWUSE. There is no enforced upper limit on wuFlow, however, unrealistically large values can cause runtime errors.

Units	Legal Range	Default	Required	Variability
gpm	x \(\le\) 0	0	No	hourly

wuHotF=float

Fraction of draw that is hot water. Cannot be specified with wuTemp or wuHeatRecEF.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	1	No	hourly

wuTemp=float

Mixed-water use temperature at the fixture. Cannot be specified when wuHotF is given.

Units	Legal Range	Default	Required	Variability
oF	x \(\le\) 0	0	when wuHeatRecEF is given or parent DHWSYS includes DHWHEATREC(s)	hourly

wuHeatRecEF=float

Heat recovery effectiveness, allows simple modeling of heat recovery devices such as drain water heat exchangers.

If non-0 (evaluated hourly), hot water use is reduced based on wuTemp, DHWSYS wsTUse, and DHWSYS wsTInlet. DHWHEATREC(s), if any, are ignored for this use. wuTemp must be specified.

If 0, detailed heat recovery modeling may apply, see DHWHEATREC.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 0.9	0	No	hourly

wuHWEndUse=choice

Hot-water end use: one of Shower, Bath, CWashr, DWashr, or Faucet. wuHWEndUse has the following functions –

• Allocation of hot water use among multiple DHWSYSs (if more than one DHWSYS references a given DHWDAYUSE).
• DHWMETER end-use accounting (via DHWSYS).
• Activation of the detailed heat recovery model (available for end use Shower when wuHeatRecEF=0 and the parent DHWSYS includes DHWHEATREC(s)).

Units	Legal Range	Default	Required	Variability
	One of above choices	(use allocated to Unknown)	No	constant

wuEventID=integer

User-defined identifier that associates multiple DHWUSEs with a single event or activity. For example, a dishwasher uses water at several discrete times during a 90 minute cycle and all DHWUSEs would be assigned the same wuEventID. All DHWUSEs having the same wuEventID should have the same wuHWEndUse.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	0	No	constant

endDHWUSE

Optionally indicates the end of the DHWUSE definition.

Units	Legal Range	Default	Required	Variability
		none	No

Related Probes:

• @DHWUse

4.32 DHWSYS

DHWSYS constructs an object representing a domestic hot water system consisting of one or more hot water heaters, storage tanks, loops, and pumps (DHWHEATER, DHWTANK, DHWLOOP, and DHWPUMP, see below) and a distribution system characterized by loss parameters. This model is based on Appendix B of the 2019 Residential ACM Reference Manual and the Ecotope HPWHSim air source heat pump water heater model (called HPWH herein).

The parent-child structure of DHWSYS components is determined by input order. For example, DHWHEATERs belong to the DHWSYS that precedes them in the input file. The following hierarchy shows the relationship among components. Note that any of the commands can be repeated any number of times.

• DHWSYS
  • DHWHEATER
  • DHWLOOPHEATER
  • DHWHEATREC
  • DHWTANK
  • DHWPUMP
  • DHWLOOP
    • DHWLOOPPUMP
    • DHWLOOPSEG
      • DHWLOOPBRANCH

Minimal modeling is included for physically realistic controls. For example, if several DHWHEATERs are included in a DHWSYS, an equal fraction of the required hot water is assumed to be produced by each heater, even if they are different types or sizes. Thus a DHWSYS is in some ways a collection of components as opposed to an explicitly connected system. This approach avoids requiring detailed input that would impose impractical user burden, especially in compliance applications.

dhwsysName

Optional name of system; give after the word “DHWSYS” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

wsCalcMode=choice

Enables preliminary simulation that derives values needed for simulation.

PRERUN	Calculate hot water heating load; at end of run, derive whLDEF for all child DHWHEATERs for which that value is required and defaulted (this emulates methods used in the T24DHW.DLL implementation of CEC DHW procedures). Also derived are average number of draws per day by end use (used in the wsDayWaste scheme).
SIMULATE	Perform full modeling calculations

To use PRERUN efficiently, the recommended input file structure is:

• General input
• DHWSYS(s) and child objects
• RUN
• ALTER DHWSYS input (as needed)
• Building input
• RUN

This order avoids duplicate time-consuming simulation of the full building model.

Units	Legal Range	Default	Required	Variability
	Codes listed above	SIMULATE	No

wsCentralDHWSYS=dhwsysName

Name of the central DHWSYS that serves this DHWSYS, allowing representation of multiple units having distinct distribution configurations and/or water use patterns but served by a central DHWSYS. The child DHWSYS(s) may not include DHWHEATERs – they are “loads only” systems. wsCentralDHWSYS and wsLoadShareDHWSYS cannot both be given.

Units	Legal Range	Default	Required	Variability
	name of a DHWSYS	DHWSYS is standalone	No	constant

wsLoadShareDHWSYS=dhwsysName

Name of a DHWSYS that serves the same loads as this DHWSYS, allowing representation of multiple water heating systems within a unit. If given, wsUse and wsDayUse are not allowed, hot water requirements are derived from the referenced DHWSYS. wsCentralDHWSYS and wsLoadShareDHWSYS cannot both be given.

For example, two DHWSYSs should be defined to model two water heating systems serving a load represented by wsDayUse DayUseTyp. Each DHWSYS should include DHWHEATER(s) and other components as needed. DHWSYS Sys1 should specify wsDayUse=DayUseTyp and DHWSYS Sys2 should have wsLoadShareDHWSYS=Sys1 in place of wsDayUse.

Loads are shared by assigning DHWUSE events sequentially by end use to all DHWSYS with compatible fixtures (determined by wsFaucetCount, wsShowerCount etc., see below) in the group. This algorithm approximately divides load for each end use by the number of compatible fixtures in the group. In addition, assigning 0 to a fixture type prevents assignment of an end use load to a DHWSYS – for example, wsDWashrCount=0 could be provided for a DHWSYS that does not serve a kitchen.

Units	Legal Range	Default	Required	Variability
	name of a DHWSYS	No shared loads	No	constant

wsMult=float

Number of identical systems of this type (including all child objects). Any value \(> 1\) is equivalent to repeated entry of the same DHWSYS. A value of 0 is equivalent to omitting the DHWSYS. Non-integral values scale all results; this may be useful in parameterized models, for example.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	constant

wsFaucetCount=integer
wsShowerCount=integer
wsBathCount=integer
wsCWashrCount=integer
wsDWashrCount=integer

Specifies the count of fixtures served by this DHWSYS that can accommodate draws of each end use (see DHWUSE). These counts are used for distributing draws in shared load configurations (multiple DHWSYSs serving the same loads, see wsLoadShareDHWSYS above).

In addition, wsShowerCount participates in assignment of Shower draws to DHWHEATRECs (if any).

Unless this DHWSYS is part of a shared-load group or includes DHWHEATREC(s), these counts have no effect and need not be specified.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	constant

wsTInlet=float

Specifies cold (mains) water temperature supplying this DHWSYS. DHWHEATER supply water temperature wsTInlet adjusted (increased) by any DHWHEATREC recovered heat and application of wsSSF (approximating solar preheating).

Units	Legal Range	Default	Required	Variability
oF	\(>\) 32 oF	Mains temp from weather file	No	hourly

wsTInletTest=float

Overides at the substep interval the cold (mains) water temperature supplying this DHWSYS.

CAUTION: wsTInletTest is intended for testing and model validation studies and should not be generally used. It is not fully supported for all DHWSYS configurations. wsTInletTest is allowed only for configurations using HPWH-based DHWHEATERs (whHeatSrc=ASHPX or whHeatSrc=RESISTANCEX).

Units	Legal Range	Default	Required	Variability
oF	\(>\) 32 oF		No	subhourly

wsTInletDes=float

Cold water inlet design temperature for sizing.

Units	Legal Range	Default	Required	Variability
oF	x \(>\) 32 oF	Annual minimums mains temperature	No	constant

wsUse=float

Hourly hot water use (at the point of use). See further info under wsDayUse.

Units	Legal Range	Default	Required	Variability
gal	x \(\ge\) 0	0	No	hourly

wsUseTest=float

Additional substep hot water use added to draw(s) specfied by wsHWUse and wsDayUse.

CAUTION: wsUseTest is intended for testing and model validation studies and should not be generally used. It is not fully supported for all DHWSYS configurations. wsUseTest is allowed only for configurations using HPWH-based DHWHEATERs (whHeatSrc=ASHPX or whHeatSrc=RESISTANCEX).

Units	Legal Range	Default	Required	Variability
gal	x \(\ge\) 0		No	subhourly

wsDayUse=dhwdayuseName

Name of DHWDAYUSE object that specifies a detailed schedule of mixed water use at points of hot water use (that is, “at the tap”). The mixed water amounts are used to derive hot water requirements based on specified mixing fractions or mixed water temperature (see DHWDAYUSE and DHWUSE).

The total water use modeled by CSE is the sum of amounts given by wsUse and the DWHDAYUSE schedule. DHWDAYUSE draws are resolved to minute-by-minute bins compatible with the HPWH model and wsUse/60 is added to each minute bin. Conversely, the hour total of the DHWDAYUSE amounts is included in the draw applied to non-HPWH DHWHEATERs.

wsDayUse variability is daily, so it is possible to select different schedules as a function of day type (or any other condition), as follows –

     DHWSYS "DHW1"
       ...
       wsDayUse = choose( $isWeHol, "DUSEWeekday", "DUSEWeHol")
       ...

Note that while DHWDAYUSE selection is updated daily, the DHWUSE values within the DHWDAYUSE can be altered hourly, providing additional scheduling flexibility.

Units	Legal Range	Default	Required	Variability
	name of a DHWDAYUSE	(no scheduled draws)	No	daily

wsFaucetDrawDurF=float

Water heater draw duration factor for faucets. Defined as the ratio of the actual draw duration (including time waiting for hot water to arrive at the fixture) to the nominal draw duration (as though hot water was instantly available).

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 0	0.0	No	Hourly

wsShowerDrawDurF=float

Water heater draw duration factor for showers. Defined as the ratio of the actual draw duration (including time waiting for hot water to arrive at the fixture) to the nominal draw duration (as though hot water was instantly available).

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 0	0.0	No	Hourly

wsBathDrawDurF=float

Water heater draw duration factor for baths. Defined as the ratio of the actual draw duration (including time waiting for hot water to arrive at the fixture) to the nominal draw duration (as though hot water was instantly available).

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 0	0.0	No	Hourly

wsCWashrDrawDurF=float

Water heater draw duration factor for clothes washers. Defined as the ratio of the actual draw duration (including time waiting for hot water to arrive at the fixture) to the nominal draw duration (as though hot water was instantly available).

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 0	1.0	No	Hourly

wsDWashrDurF=float

Water heater draw duration factor for dishwashers. Defined as the ratio of the actual draw duration (including time waiting for hot water to arrive at the fixture) to the nominal draw duration (as though hot water was instantly available).

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 0	1.0	No	Hourly

wsUnkDrawDurF=float

Water heater draw duration factor for unknown end use. Defined as the ratio of the actual draw duration (including time waiting for hot water to arrive at the fixture) to the nominal draw duration (as though hot water was instantly available).

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 0	0.0	No	Hourly

wsFaucetDrawWaste=float

Draw water waste for faucets. Specifies additional draw volume per DHWUSE event (at fixture, by end use). This can be used to account for water discarded during warmup or otherwise adjust the draw volume. Because the values are at the fixture, the impact on hot water demand additionally depends on DHWUSE parameters. The value is applied by lengthening (or shortening) the draw duration.

Units	Legal Range	Default	Required	Variability
gal/draw	x \(\geq\) 0	0.0	No	Hourly

wsShowerDrawWaste=float

Draw water waste for showers. Specifies additional draw volume per DHWUSE event (at fixture, by end use). This can be used to account for water discarded during warmup or otherwise adjust the draw volume. Because the values are at the fixture, the impact on hot water demand additionally depends on DHWUSE parameters. The value is applied by lengthening (or shortening) the draw duration.

Units	Legal Range	Default	Required	Variability
gal/draw	x \(\geq\) 0	0.0	No	Hourly

wsBathDrawWaste=float

Draw water waste for baths. Specifies additional draw volume per DHWUSE event (at fixture, by end use). This can be used to account for water discarded during warmup or otherwise adjust the draw volume. Because the values are at the fixture, the impact on hot water demand additionally depends on DHWUSE parameters. The value is applied by lengthening (or shortening) the draw duration.

Units	Legal Range	Default	Required	Variability
gal/draw	x \(\geq\) 0	0.0	No	Hourly

wsCWashrDrawWaste=float

Draw water waste for clothes washers. Specifies additional draw volume per DHWUSE event (at fixture, by end use). This can be used to account for water discarded during warmup or otherwise adjust the draw volume. Because the values are at the fixture, the impact on hot water demand additionally depends on DHWUSE parameters. The value is applied by lengthening (or shortening) the draw duration.

Units	Legal Range	Default	Required	Variability
gal/draw	x \(\geq\) 0	0.0	No	Hourly

wsDWashrDrawWaste=float

Draw water waste for dishwashers. Specifies additional draw volume per DHWUSE event (at fixture, by end use). This can be used to account for water discarded during warmup or otherwise adjust the draw volume. Because the values are at the fixture, the impact on hot water demand additionally depends on DHWUSE parameters. The value is applied by lengthening (or shortening) the draw duration.

Units	Legal Range	Default	Required	Variability
gal/draw	x \(\geq\) 0	0.0	No	Hourly

wsUnkDrawWaste=float

Draw water waste for unknown end use. Specifies additional draw volume per DHWUSE event (at fixture, by end use). This can be used to account for water discarded during warmup or otherwise adjust the draw volume. Because the values are at the fixture, the impact on hot water demand additionally depends on DHWUSE parameters. The value is applied by lengthening (or shortening) the draw duration.

Units	Legal Range	Default	Required	Variability
gal/draw	x \(\geq\) 0	0.0	No	Hourly

wsTRLTest=float

Circulation loop return temperature for testing and validation.

Units	Legal Range	Default	Required	Variability
F	x \(\geq\) 0	0.0	No	Subhourly

wsVolRLTest=float

Circulation loop volume flow rate for testing and validation.

Units	Legal Range	Default	Required	Variability
gpm	x \(\geq\) 0	0.0	No	Subhourly

wsBranchModel=choice

Branch model selection.

wsBranchModel	Description
T24DHW	Model in appendix B of the Alternative Compliance Manual
DRAWWASTE	Draw duration increase per draw waste
DAYWASTE	draw duration increase per day waste

wsDayWasteVol=float

Average amount of waste per day.

Units	Legal Range	Default	Required	**Variability
gal/day	x \(\ge\) 0	wsDayWasteBranchVolF * (Total DHWLOOPBRANCH vol)	No	constant

wsDayWasteBranchVolF=float

Day waste scaling factor.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	constant

wsFaucetDayWasteF=float

Relative faucet water draw for day of waste scheme.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.0	No	subhourly

wsShowerDayWasteF=float

Relative shower water draw for day of waste scheme.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.0	No	subhourly

wsBathDayWasteF=float

Relative bath water draw for day of waste scheme.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.0	No	subhourly

wsCWashrDayWasteF=float

Relative clothes washer water draw for day of waste scheme.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.0	No	subhourly

wsDWashrDayWasteF=float

Relative dish washer water draw for day of waste scheme.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.0	No	subhourly

wsUnkDayWasteF=float

Unknown relative water draw for day of waste scheme.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.0	No	subhourly

wsTUse=float

Hot water delivery temperature (at output of water heater(s) and at point of use). Delivered water is mixed down to wsTUSe (with cold water) or heated to wsTUse (with extra electric resistance backup, see DHWHEATER whXBUEndUse). Note that draws defined via DHWDAYUSE / DHWUSE can specify mixing to a lower temperature.

Units	Legal Range	Default	Required	Variability
oF	\(>\) 32 oF	120	No	hourly

wsTUseTest=float

Overides at the substep interval the hot water delivery temperature.

CAUTION: wsTUseTest is intended for testing and model validation studies and should not be generally used. It is not fully supported for all DHWSYS configurations. wsTUseTest is allowed only for configurations using HPWH-based DHWHEATERs (whHeatSrc=ASHPX or whHeatSrc=RESISTANCEX).

Units	Legal Range	Default	Required	Variability
oF	\(>\) 32 oF		No	subhourly

wsTSetPoint=float

Specifies the hot water setpoint temperature for all child DHWHEATERs. Used only for HPWH-based DHWHEATERs (HPWH models tank temperatures and heating controls), otherwise has no effect. wsTSetpoint can be modified hourly to achieve load-shifting effects.

Units	Legal Range	Default	Required	Variability
oF	\(>\) 32 oF	wsTUse	No	hourly

wsTSetPointLH=float

Specifies the hot water set point temperature for all child DHWLOOPHEATERs. Used only for HPWH-based DHWHLOOPEATERs (HPWH explicitly models tank temperatures and heating controls), otherwise has no effect.

Units	Legal Range	Default	Required	Variability
oF	\(>\) 32 oF	wsTSetPoint	No	hourly

wsTSetpointDes=float

Specifies the design (sizing) set point temperature.

Units	Legal Range	Default	Required	Variability
oF	x \(>\) 32 oF	wsTUse	No	constant

wsVolRunningDes=float

Running volume for design. Active volume (above aquastat) equals to a full tank volume, defaults from EcoSizer at end of prerun if not input. No direct use, must be passed to DHWHEATER via ALTER.

Units	Legal Range	Default	Required	Variability
gal	x \(>\) 0	0.0	No	constant

wsASHPTSrcDes=float

Design (sizing) source air temperature for HPWH DHWHEATERs.

Units	Legal Range	Default	Required	Variability
oF	x \(>\) 32 oF	Heating design temperature	No	At the start and at the end of interval

wsFxDes=float

Excess size factor for domestic hot water design. wsFxDes is applied when wsHeatingCapDes and/or wsVolRunningDes are defaulted from EcoSizer at the end of the prerun. There is no effect if those values are input.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1.0	No	constant

wsDRMethod=choice

Selects alternative control schemes for HPWH-based DHWHEATERs. These allow shifting primary heater (compressor or resistance element) operation to times of day that have load-management advantages.

wsDRMethod	Description
NONE	None (default setpoint-based control)
SCHEDULE	Demand response schedule (see wsDRSignal)
STATEOFCHARGE	State-of-charge (see wsTargetSOC)

Units	Legal Range	Default	Required	Variability
	See table above	NONE	No	constant

wsDRSignal=choice

When (and only when) wsDRMethod=SCHEDULE, wsDRSignal allows hourly specification of modified control schemes. Available signals are:

wsDRSignal	Description
ON	Normal operation following the water heater’s internal control logic.
TOO	Tops off the tank once by engaging the all the available heating sources (compressor and resistive elements) in the water heater to heat the tank to setpoint (regardless of the current condition).
TOOLOR	Tops off the tank once and locks out the resistance elements (only the compressor is used to heat the tank to setpoint).
TOOLOC	Tops off the tank once and locks out the compressor (only the resistance elements are used to heat the tank to setpoint).
TOT	Tops off the tank on a timer using all the available heating sources (compressor and resistive elements) in the water heater. The tank starts a timer and heating to setpoint when the call is received and repeats the heating call when the timer reaches zero.
TOTLOR	Tops of the tank on a timer and locks out the resistance elements (only the compressor is used to heat the tank to setpoint).
TOTLOC	Tops of the tank on a timer and locks out the compressor (only the resistance elements are used to heat the tank to setpoint).
LOC	Locks out the compressor from the water heater’s normal internal control logic.
LOR	Locks out the resistive elements from the water heater’s normal internal control logic.
LOCLOR	Locks out the compressor and resistive elements from the water heater’s normal internal control logic.

Scheduling functions can be used to construct control strategies of interest, for example:

wsDRSignal = $isWeHol
  ? hourval( on,  on,  on,  on,  on,  on,  on,  on,  on,  on,  on,  on,
            on,  on,  on,  on,  on,  on, TOO, LOC, LOR,  on,  on,  on)
  : hourval( on,  on,  on,  on,  on,     on,     on,  on,  on,  on,  on,  on,
            on,  on,  on,  on,  TOOLOR, TOOLOR, LOC, LOR, LOR, LOR,  on,  on)

Note also that wsTSetpoint can be also be modified hourly to achieve load-shifting effects.

Units	Legal Range	Default	Required	Variability
	See Table above	ON	No	hourly

wsTargetSOC=float

When (and only when) wsDRMethod=STATEOFCHARGE, wsTargetSOC specifies the target fraction of maximum tank heat content. The tank is deemed fully charged when its entire contents is at wsTSetpoint and 0 charged at 110 ^oF. Schedules are used to indicate anticipated heat requirements. The STATEOFCHARGE method can be used in combined heat / DHW systems (see RSYS rsType=COMBINEDHEATDHW) when there is excess capacity during summer months, as shown in the following:

wsTargetSOC = select(
  $month > 11 || $month < 3,
      hourval(.70,.70,.70,.70,.70,.70,.70,.30,.95,.95,.95,.95,
              .95,.95,.95,.95,.95,.70,.70,.70,.70,.70,.70,.70),
  $month==3 || $month== 4,
      hourval(.50,.50,.50,.50,.50,.50,.50,.30,.95,.95,.95,.95,
              .95,.95,.95,.95,.95,.50,.50,.50,.50,.50,.50,.50),
  default
      hourval(.15,.15,.15,.15,.15,.15,.15,.15,.15,.15,.15,.15,
              .15,.60,.60,.60,.15,.15,.15,.15,.15,.15,.15,.15))

Units	Legal Range	Default	Required	Variability
	0 \(\lt\) x \(\le\) 1	0.9	No	hourly

wsSDLM=float

Specifies the standard distribution loss multiplier. See App B Eqn 4. To duplicate CEC 2019 methods, this value should be set according to the value derived with App B Eqn 5.

Units	Legal Range	Default	Required	Variability
	\(>\) 0	1	No	constant

wsDSM=float

Distribution system multiplier. See RACM App B Eqn 4. To duplicate CEC 2016 methods, wsDSM should be set to the appropriate value from App B Table B-2. Note the NCF (non-compliance factor) included in App B Eqn 4 is not a CSE input and thus must be applied externally to wsDSM.

Units	Legal Range	Default	Required	Variability
	\(>\) 0	1	No	constant

wsWF=float

Waste factor. See RACM App B Eqn 1. wsWF is applied to hot water draws. The default value (1) reflects the inclusion of waste in draw amounts. App B specifies wsWF=0.9 when the system has a within-unit pumped loop that reduces waste due to immediate availability of hot water at fixtures.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	hourly

wsSSF=float

NOTE: Deprecated. Use wsSolarSys instead.

Specifies the solar savings fraction, allowing recognition of externally-calculated solar water heating energy contributions. The contributions are modeled by deriving an increased water heater feed temperature –

\[tWHFeed = tInletAdj + wsSSF*(wsTUse-tInletAdj)\]

where tInletAdj is the source cold water temperature including any DHWHEATREC tempering (that is, wsTInlet + heat recovery temperature increase, if any). This model approximates the diminishing returns associated with combined preheat strategies such as drain water heat recovery and solar.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 0.99		No	hourly

wsSolarSys=dhwSolarSys

Name of DHWSOLARSYS object, if any, that supplies pre-heated water to this DHWSYS.

Units	Legal Range	Default	Required	Variability
	name of a DHWSOLARSYS	not recorded	No	constant

wsParElec=float

Specifies electrical parasitic power to represent recirculation pumps or other system-level electrical devices. Calculated energy use is accumulated to the METER specified by wsElecMtr (end use DHW). No other effect, such as heat gain to surroundings, is modeled.

Units	Legal Range	Default	Required	Variability
W	x \(\ge\) 0	0	No	hourly

wsDrawMaxDur=integer

Maximum draw duration for the sizing window.

Units	Legal Range	Default	Required	Variability
Hr	x \(\geq\) 0	4	No	constant

wsLoadMaxDur=integer

Maximum load duration for the sizing window.

Units	Legal Range	Default	Required	Variability
Hr	x \(\geq\) 0	12	No	constant

wsElecMtr=mtrName

Name of METER object, if any, to which DHWSYS electrical energy use is recorded (under end use DHW). In addition, wsElecMtr provides the default whElectMtr selection for all DHWHEATERs and DHWPUMPs in this DHWSYS.

Units	Legal Range	Default	Required	Variability
	name of a METER	not recorded	No	constant

wsFuelMtr =mtrName

Name of METER object, if any, to which DHWSYS fuel energy use is recorded (under end use DHW). DHWSYS fuel use is usually (always?) 0, so the primary use of this input is to specify the default whFuelMtr choice for DHWHEATERs in this DHWSYS.

Units	Legal Range	Default	Required	Variability
	name of a METER	not recorded	No	constant

wsWHhwMtr=dhwmtrName

Name of DHWMETER object, if any, to which hot water quantities (at water heater) are recorded by hot water end use.

Units	Legal Range	Default	Required	Variability
	name of a METER	not recorded	No	constant

wsFXhwMtr =dhwmtrName

Name of DHWMETER object, if any, to which mixed hot water use (at fixture) quantities are recorded by hot water end use. DHWDAYUSE and wsUse input can be verified using DHWMETER results.

Units	Legal Range	Default	Required	Variability
	name of a METER		No	constant

wsWriteDrawCSV=choice

If Yes, a comma-separated file is generated containing 1-minute interval hot water draw values for testing or linkage purposes.

Units	Legal Range	Default	Required	Variability
	Yes or No	No	No	constant

endDHWSys

Optionally indicates the end of the DHWSYS definition.

Units	Legal Range	Default	Required	Variability
		none	No

Related Probes:

• @DHWSys

4.33 DHWHEATER

DHWHEATER constructs an object representing a domestic hot water heater (or several if identical).

whName

Optional name of water heater; give after the word “DHWHEATER” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

whMult=integer

Number of identical water heaters of this type. Any value \(>1\) is equivalent to repeated entry of the same DHWHEATER.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

whType=choice

Type of water heater. This categorization is based on CEC and federal rating standards that change from time to time.

SMALLSTORAGE	A storage water heater having an energy factor (EF) rating. Generally, a gas-fired storage water heater with input of 75,000 Btuh or less, an oil-fired storage water heater with input of 105,000 Btuh or less, an electric storage water heater with input of 12 kW or less, or a heat pump water heater rated at 24 amps or less.
LARGESTORAGE	Any storage water heater that is not SMALLSTORAGE.
SMALLINSTANTANEOUS	A water heater that has an input rating of at least 4,000 Btuh per gallon of stored water. Small instantaneous water heaters include: gas instantaneous water heaters with an input of 200,000 Btu per hour or less, oil instantaneous water heaters with an input of 210,000 Btu per hour or less, and electric instantaneous water heaters with an input of 12 kW or less.
LARGEINSTANTANEOUS	An instantaneous water heater that does not conform to the definition of SMALLINSTANTANEOUS, an indirect fuel-fired water heater, or a hot water supply boiler.
INSTANTANEOUSUEF	An instantaneous water heater having a UEF rating (as opposed to EF).

Units	Legal Range	Default	Required	Variability
	Codes listed above	SMALLSTORAGE	No	constant

whHeatSrc=choice

Heat source for water heater. CSE implements uses efficiency-based models for all whTypes (as documented in RACM, App. B). In addition, the detailed Ecotope HPWH model is available for electric (air source heat pump and resistance) SMALLSTORAGE water heaters.

RESISTANCE	Electric resistance heating element Deprecated for whType=SMALLSTORAGE (use RESISTANCEX)
RESISTANCEX	Electric resistance heating element, detailed HPWH model
ASHP	Air source heat pump, EF model Deprecated for whType=SMALLSTORAGE (use ASHPX)
ASHPX	Air source heat pump, detailed HPWH model
FUEL	Fuel-fired burner

Units	Legal Range	Default	Required	Variability
	Codes listed above	FUEL	No	constant

whResType=choice

Resistance heater type, valid only if whHeatSrc is equal to RESISTANCEX, else ignored. These choices are supported by the detailed HPWH model. Except for Generic, all heater characteristics are set by HPWH based on whResType.

Units	Legal Range	Default	Required	Variability
	Typical SwingTank	Typical	No	constant

whHeatingCap=float

Nominal heating capacity, available only for a limited HPWH types.

Units	Legal Range	Default	Required	Variability
Btuh	x \(>\) 0	0	No	constant

whVol=float

Storage tank volume. Must be omitted or 0 for instantaneous whTypes. Used by HPWH model (whHeatSrc=RESISTANCEX or whHeatSrc=ASHPX). Required when whHeatSrc=RESISTANCEX or whHeatSrc=ASHPX with whASHPType=GENERIC. For all other configurations, whVol is documentation-only.

Units	Legal Range	Default	Required	Variability
gal	\(\ge\) 0.1 (caution: small values may cause runtime errors)	per whASHPType if HPWH else 50	For some HPWH configurations, see above	constant

whVolRunning=float

Running storage volume is the volume above aquastat. Requires the total volume based on aquastat position. Ecotope’s HPWH tank and heater.

Units	Legal Range	Default	Required	Variability
gal	x \(>\) 0	0	No	constant

whEF=float

Rated energy factor that specifies DHWHEATER efficiency under test conditions. Used by CSE to derive annual water heating efficiency and/or other characteristics as described below. Calculation methods are documented in RACM, Appendix B.

Configuration	whEF default	Use
whType=SMALLSTORAGE, whHeatSrc=RESISTANCE or FUEL	0.82	Derivation of whLDEF
whType=SMALLSTORAGE, whHeatSrc=ASHP	0.82	Derivation of whLDEFnote inappropriate default (deprecated, use ASHPX)
whType=SMALLSTORAGE, whHeatSrc=ASHPX, whASHPType=GENERIC	(req’d)	Tank losses Overall efficiency
whType=SMALLSTORAGE, whHeatSrc=RESISTANCEX	(req’d)	Tank losses Note: maximum whEF=0.98.
whType=SMALLINSTANTANEOUS, whHeatSrc=RESISTANCE or FUEL	0.82	Annual efficiency = whEF*0.92
Any other	(unused)

Units	Legal Range	Default	Required	Variability
	\(>\) 0 Caution: maximum not checked. Unrealistic values will cause runtime errors and/or invalid results	See above	See above	constant

whLDEF=float

Load-dependent energy factor for DHWHEATERs with whType=SMALLSTORAGE and whHeatSrc=FUEL or whHeatSrc=RESISTANCE. If not given, whLDEF is derived using a preliminary simulation activated via DHWSYS wsCalcMode=PRERUN. See RACM Appendix B.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	Calculated via DHWSYS PreRun mechanism	When whType = SMALLSTORAGE and PreRun not used	constant

whUEF=float

Water heater Uniform Energy Factor efficiency rating, used when whType=INSTANTANEOUSUEF.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	none	when whType= INSTANTANEOUSUEF	constant

whAnnualElec=float

Annual electricity use assumed in UEF rating derivation. Used when whType=INSTANTANEOUSUEF.

Units	Legal Range	Default	Required	Variability
kWh	x \(\ge\) 0	none	when whType= INSTANTANEOUSUEF	constant

whAnnualFuel=float

Annual fuel use assumd in UEF rating derivation, used when whType=INSTANTANEOUSUEF.

Units	Legal Range	Default	Required	Variability
therms	x \(\ge\) 0	none	when whType= INSTANTANEOUSUEF	constant

whRatedFlow=float

Maximum flow rate assumed in UEF rating derivation. Used when whType=INSTANTANEOUSUEF.

Units	Legal Range	Default	Required	Variability
gpm	x \(>\) 0	none	when whType= INSTANTANEOUSUEF	constant

whStbyElec=float

Instantaneous water heater standby power (electricity consumed when heater is not operating). Used when whType=INSTANTANEOUSUEF.

Units	Legal Range	Default	Required	Variability
W	x \(\ge\) 0	4	No	constant

whLoadCFwdF=float

Instanteous water heater load carry forward factor – approximate number of hours the heater is allowed to meet water heating demand that is unmet on a 1 minute basis, used when whType=INSTANTANEOUSUEF.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	constant

whZone=znName

Name of zone where water heater is located, used only in detailed HPWH models (whHeatSrc=ASHPX or whHeatSrc=RESISTANCEX), otherwise no effect. Zone conditions are used for tank heat loss calculations. Heat losses from the DHWHEATER are included in the zone heat balance. whZone also provides the default for whASHPSrcZn (see below).

whZone and whTEx cannot both be specified.

Units	Legal Range	Default	Required	Variability
	name of a ZONE	Not in a zone (heat losses discarded)	No	constant

whTEx=float

Water heater surround temperature, used only in detailed HPWH models (whHeatSrc=ASHPX or whHeatSrc=RESISTANCEX), otherwise no effect. When whTEx is specified, tank heat losses are calculated using whTEx and modify tank water temperatures, but the lost heat has no external effect.

whZone and whTEx cannot both be specified.

Units	Legal Range	Default	Required	Variability
oF	x \(\ge\) 0	whZone air temperature if specified, else 70 oF	No	hourly

whASHPType=choice

Air source heat pump type, valid only if whHeatSrc=ASHPX. These choices are supported by the detailed HPWH model. Except for Generic, all heater characteristics are set by HPWH based on whASHPType.

Choice	Specified type
Generic	General generic (parameterized by wh_EF and wh_vol)
AOSmithPHPT60	60 gallon Voltex
AOSmithPHPT80	80 gallon Voltex
AOSmithHPTU50	50 gallon AOSmith HPTU
AOSmithHPTU66	66 gallon AOSmith HPTU
AOSmithHPTU80	80 gallon AOSmith HPTU
AOSmithHPTU80DR	80 gallon AOSmith HPTU (demand reduction variant)
AOSmithCAHP120	120 gallon AOSmith
Sanden40	Sanden 40 gallon CO2 external heat pump
Sanden80	Sanden 80 gallon CO2 external heat pump
Sanden120	Sanden 120 gallon CO2 external heat pump
SandenGS3	Sanden GS3 compressor CO2 external
GE2012	2012 era GeoSpring
GE2014	2014 80 gal GE model run in the efficiency mode
GE2014_80DR	2014 80 gal GE model run in the efficiency mode (demand reduction variant)
GE2014StdMode	2014 50 gal GE run in standard mode
GE2014StdMode80	2014 80 gal GE run in standard mode
RheemHB50	newish Rheem (2014 model?)
RheemHBDR2250	50 gallon, 2250 W resistance Rheem HB Duct Ready
RheemHBDR4550	50 gallon, 4500 W resistance Rheem HB Duct Ready
RheemHBDR2265	65 gallon, 2250 W resistance Rheem HB Duct Ready
RheemHBDR4565	65 gallon, 4500 W resistance Rheem HB Duct Ready
RheemHBDR2280	80 gallon, 2250 W resistance Rheem HB Duct Ready
RheemHBDR4580	80 gallon, 4500 W resistance Rheem HB Duct Ready
Rheem2020Prem40	40 gallon, Rheem 2020 Premium
Rheem2020Prem50	50 gallon, Rheem 2020 Premium
Rheem2020Prem65	65 gallon, Rheem 2020 Premium
Rheem2020Prem80	80 gallon, Rheem 2020 Premium
Rheem2020Build40	40 gallon, Rheem 2020 Builder
Rheem2020Build50	50 gallon, Rheem 2020 Builder
Rheem2020Build65	65 gallon, Rheem 2020 Builder
Rheem2020Build80	80 gallon, Rheem 2020 Builder
RheemPlugInShared40	40 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInShared50	50 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInShared65	65 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInShared80	80 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInDedicated40	40 gal Rheem plug-in 120V dedicated circuit (no resistance elements)
RheemPlugInDedicated50	50 gal Rheem plug-in 120V dedicated circuit (no resistance elements)
Stiebel220E	Stiebel Eltron (2014 model?)
AOSmithSHPT50	AOSmith add’l models (added 3-24-2017)
AOSmithSHPT66	AOSmith add’l models (added 3-24-2017)
AOSmithSHPT80	AOSmith add’l models (added 3-24-2017)
GenericTier1	Generic Tier 1
GenericTier2	Generic Tier 2
GenericTier3	Generic Tier 3
Generic	General generic (parameterized by EF and vol)
UEF2Generic	Experimental UEF=2
WorstCaseMedium	UEF2Generic alias (supports pre-existing test cases)
BasicIntegrated	Typical integrated HPWH
ResTank	Resistance heater (no compressor). Superceded by whHeatSrc=RESITANCEX
ResTankNoUA	Resistance heater (no compressor) with no tank losses. Superseded by whHeatSrc=RESISTANCEX.
AOSmithHPTU80DR	80 gallon AOSmith HPTU with fixed backup setpoint (experimental for demand response testing)
AOSmithSHPT50	50 gal AOSmith SHPT
AOSmithSHPT66	66 gal AOSmith SHPT
AOSmithSHPT80	80 gal AOSmith SHPT
AOSmithHPTS40	40 gal AOSmith HPTS
AOSmithHPTS50	50 gal AOSmith HPTS
AOSmithHPTS66	66 gal AOSmith HPTS
AOSmithHPTS80	80 gal AOSmith HPTS
ColmacCxV5_SP	Colmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA10_SP	Colmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA15_SP	Colmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA20_SP	Colmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA25_SP	Colmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA30_SP	Colmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxV5_MP	Colmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA10_MP	Colmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA15_MP	Colmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA20_MP	Colmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA25_MP	Colmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA30_MP	Colmac CxA-xx modular external HPWHs (multi-pass mode)
NyleC25A_SP	Nyle Cxx external HPWHs (SP = single pass mode)
NyleC60A_SP	Nyle Cxx external HPWHs (SP = single pass mode)
NyleC90A_SP	Nyle Cxx external HPWHs (SP = single pass mode)
NyleC125A_SP	Nyle Cxx external HPWHs (SP = single pass mode)
NyleC185A_SP	Nyle Cxx external HPWHs (SP = single pass mode)
NyleC250A_SP	Nyle Cxx external HPWHs (SP = single pass mode)
NyleC60A_CWP_SP	Nyle Cxx external SP HPWHs with cold weather package
NyleC90A_CWP_SP	Nyle Cxx external SP HPWHs with cold weather package
NyleC125A_CWP_SP	Nyle Cxx external SP HPWHs with cold weather package
NyleC185A_CWP_SP	Nyle Cxx external SP HPWHs with cold weather package
NyleC250A_CWP_SP	Nyle Cxx external SP HPWHs with cold weather package
NyleC60A_MP	Nyle Cxx external HPWHs (MP = multi-pass mode)
NyleC90A_MP	Nyle Cxx external HPWHs (MP = multi-pass mode)
NyleC125A_MP	Nyle Cxx external HPWHs (MP = multi-pass mode)
NyleC185A_MP	Nyle Cxx external HPWHs (MP = multi-pass mode)
NyleC250A_MP	Nyle Cxx external HPWHs (MP = multi-pass mode)
NyleC60A_CWP_MP	Nyle Cxx external MP HPWHs w/ cold weather package
NyleC90A_CWP_MP	Nyle Cxx external MP HPWHs w/ cold weather package
NyleC125A_CWP_MP	Nyle Cxx external MP HPWHs w/ cold weather package
NyleC185A_CWP_MP	Nyle Cxx external MP HPWHs w/ cold weather package
NyleC250A_CWP_MP	Nyle Cxx external MP HPWHs w/ cold weather package
Rheem_HPHD60HNU_MP	Rheem HPHD60 MP external MP HPWHs
Rheem_HPHD60VNU_MP	Rheem HPHD60 MP external MP HPWHs
Rheem_HPHD135HNU_MP	Rheem HPHD135 MP external MP HPWHs
Rheem_HPHD135VNU_MP	Rheem HPHD135 MP external MP HPWHs
Scalable_SP	single pass scalable type for autosized standard design
Scalable_MP	multipass scalable type for autosized standard design
AquaThermAire	Villara AquaThermAire HPWH
GenericUEF217	65-gal tank meeting Federal standard minimum requirement
AWHSTier4Generic40	Any 40-gal tank meeting Advanced Water Heating Specification Tier-4 minimum requirements
AWHSTier4Generic50	Any 50-gal tank meeting Advanced Water Heating Specification Tier-4 minimum requirements
AWHSTier4Generic65	Any 65-gal tank meeting Advanced Water Heating Specification Tier-4 minimum requirements
AWHSTier4Generic80	Any 80-gal tank meeting Advanced Water Heating Specification Tier-4 minimum requirements
BradfordWhiteAeroThermRE2H50	Bradford White 50-gal AeroTherm2023
BradfordWhiteAeroThermRE2H65	Bradford White 65-gal AeroTherm2023
BradfordWhiteAeroThermRE2H80	Bradford White 80-gal AeroTherm2023
LG_APHWC50	LG 50-gal integrated HPWH
LG_APHWC80	LG 580-gal integrated HPWH

Units	Legal Range	Default	Required	Variability
	Codes listed above	none	When whHeatSrc=ASHPX	constant

whASHPSrcZn=znName

Name of zone that serves as heat pump heat source used when whHeatSrc=ASHPX. Heat removed from the zone is added to the heated water and is included in zone heat balance (that is, heat pump operation cools the zone).

whASHPSrcZn and whASHPSrcT cannot both be specified.

Units	Legal Range	Default	Required	Variability
	name of a ZONE	whZoneIf no zone is specified by input or default, heat extracted by ASHP has no effect.	No	constant

whASHPSrcT=float

Heat pump source air temperature used when whHeatSrc=ASHPX. Heat removed from this source is added to the heated water but has no other effect.

whASHPSrcZn and whASHPSrcT cannot both be specified.

The logic to determine the temperature of the heat pump source air is:

        if whASHPSrcT is specified
          use whASHPSrcT
        else if whASHPSRCZn is specified
          use whASHPSrcZn air temp
        else if whZone is specified
          use whZone air temp
        else
          use 70 F

To model a heat pump that uses outdoor air as its heat source, omit whASHPSrcZn and specify whASHPSrcT = $tDbO.

Units	Legal Range	Default	Required	Variability
oF	x \(\ge\) 0	70 oF (used only when whASHPSrcZn and whZone not specified)	No	hourly

whASHPResUse=float

Specifies activation temperature difference for resistance heating, used only when whHeatSrc=ASHPX and whASHPType=GENERIC. Refer to HPWH engineering documentation for model details.

Units	Legal Range	Default	Required	Variability
oC	x \(\ge\) 0	7.22	No	constant

whResHtPwr=float

Specifies resistance upper element power, used only with whHeatSrc=RESISTANCEX.

Units	Legal Range	Default	Required	Variability
W	x \(\ge\) 0	4500	No	constant

whResHtPwr2=float

Specifies resistance lower element power, used only with whHeatSrc=RESISTANCEX.

Units	Legal Range	Default	Required	Variability
W	x \(\ge\) 0	whResHtPwr	No	constant

whUA=float

HPWH-type total UA (not per tank)

Units	Legal Range	Default	Required	Variability
Btuh/F	x \(\geq\) 0	HPWH default	No	constant

whInsulR=float

Tank insulation resistance for heat pump water heater.

Units	Legal Range	Default	Required	Variability
hr-F/Btuh	x \(>\) 0	-1	No	constant

whInHtSupply=float
whInHtLoopRet=float

Fractional tank height of inlets for supply water and DHWLOOP return, used only with HPWH types (whHeatSrc=RESISTANCEX or whHeatSrc=ASHPX). 0 indicates the bottom of the water heater tank and 1 specifies the top. Inlet height influences tank layer mixing and can impact heat pump COP and/or heating activation frequency.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	HPWH default (0?)	No	constant

whtankCount=float

Number of storage tanks per DHWHEATER, re built-up whType=Builtup, does not reflect wh_mult (wh_mult=2, wh_tankCount=3 -> 6 tanks).

Units	Legal Range	Default	Required	Variability
#	x \(\geq\) 1	1	No	constant

whEff=float

Water heating efficiency, used in modeling whType=LARGESTORAGE and whType=LARGEINSTANTANEOUS.

Units	Legal Range	Default	Required	Variability
	0 \(<\) whEff \(\leq\) 1	.82	No	constant

whSBL=float

Standby loss, used in modeling whType=LARGESTORAGE.

Units	Legal Range	Default	Required	Variability
Btuh	x \(\ge\) 0	0	No	constant

whPilotPwr=float

Pilot light consumption, included in fuel energy use of DHWHEATERs with whHeatSrc=FUEL.

Units	Legal Range	Default	Required	Variability
Btuh	x \(\ge\) 0	0	No	hourly

whParElec=float

Parasitic electricity power, included in electrical energy use of all DHWHEATERs.

Units	Legal Range	Default	Required	Variability
W	x \(\ge\) 0	0	No	hourly

whFAdjElec=float
whFAdjFuel=float

Water heater energy use modifiers. Multiplies calculated use of electricity (whFAdjElec) and fuel (whFAdjFuel). All components of energy use – primary, backup, XBU (extra backup), and other auxiliary – are modified before they are accumulated to whElecMtr and whFuelMtr.

Units	Legal Range	Default	Required	Variability
	\(\ge\) 0	1	No	subhourly

whElecMtr=mtrName

Name of METER object, if any, by which DHWHEATER electrical energy use is recorded (under end use DHW).

Units	Legal Range	Default	Required	Variability
	name of a METER	Parent DHWSYS wsElecMtr	No	constant

whxBUEndUse=choice

Specifies the whElecMtr end use, if any, to which extra backup energy is accumulated. In some water heater types, extra backup energy is modeled to maintain output temperature at wsTUse. By default, extra backup energy is included in end use dhwBU. whxBUEndUse allows specification of an alternative end use to which extra backup energy is accumulated.

Units	Legal Range	Default	Required	Variability
	end use code	(extra backup accums to dhwBU)	No	constant

whFuelMtr =mtrName

Name of METER object, if any, by which DHWHEATER fuel energy use is recorded (under end use DHW).

Units	Legal Range	Default	Required	Variability
name of a METER	Parent DHWSYS wsFuelMtr		No	constant

whTankTInit =comma-separated list of 12 floats

A list of 12 initial values for HPWH tank model layer temperatures, in bottom-to-top order. If given, these values are used to initialize tank layer temperatures at the beginning of the warmup period. Initialization is not repeated at the beginning of the main simulation.

whTankTInit is allowed only for HPWH-based types (whHeatSrc=ASHPX or whHeatSrc=ResistanceX).

whTankTInit is intended for use in empirical validation studies where the initial tank state needs to match measured data. whTankTInit should not be generally used. In the absence of whTankTInit, layer temperatures are initialized to the water heater setpoint inherited from the parent DHWSYS.

Units	Legal Range	Default	Required	Variability
oF	x \(\gt\) 0		No	constant

endDHWHEATER

Optionally indicates the end of the DHWHEATER definition.

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 0	none	No

Related Probes:

• @DHWHeater

4.34 DHWLOOPHEATER

DHWHEATERLOOP constructs an object representing a hot water heater dedicated to heating DHWLOOP return water (or several if identical).

whName

Optional name of water heater; give after the word “DHWHEATER” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

whMult=integer

Number of identical water heaters of this type. Any value \(>1\) is equivalent to repeated entry of the same DHWHEATER.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

whType=choice

Type of water heater. This categorization is based on CEC and federal rating standards that change from time to time.

SMALLSTORAGE	A storage water heater having an energy factor (EF) rating. Generally, a gas-fired storage water heater with input of 75,000 Btuh or less, an oil-fired storage water heater with input of 105,000 Btuh or less, an electric storage water heater with input of 12 kW or less, or a heat pump water heater rated at 24 amps or less.
LARGESTORAGE	Any storage water heater that is not SMALLSTORAGE.
SMALLINSTANTANEOUS	A water heater that has an input rating of at least 4,000 Btuh per gallon of stored water. Small instantaneous water heaters include: gas instantaneous water heaters with an input of 200,000 Btu per hour or less, oil instantaneous water heaters with an input of 210,000 Btu per hour or less, and electric instantaneous water heaters with an input of 12 kW or less.
LARGEINSTANTANEOUS	An instantaneous water heater that does not conform to the definition of SMALLINSTANTANEOUS, an indirect fuel-fired water heater, or a hot water supply boiler.
INSTANTANEOUSUEF	An instantaneous water heater having a UEF rating (as opposed to EF).

Units	Legal Range	Default	Required	Variability
	Codes listed above	SMALLSTORAGE	No	constant

whHeatSrc=choice

Heat source for water heater. CSE implements uses efficiency-based models for all whTypes (as documented in RACM, App. B). In addition, the detailed Ecotope HPWH model is available for electric (air source heat pump and resistance) SMALLSTORAGE water heaters.

RESISTANCE	Electric resistance heating element Deprecated for whType=SMALLSTORAGE (use RESISTANCEX)
RESISTANCEX	Electric resistance heating element, detailed HPWH model
ASHP	Air source heat pump, EF model Deprecated for whType=SMALLSTORAGE (use ASHPX)
ASHPX	Air source heat pump, detailed HPWH model
FUEL	Fuel-fired burner

Units	Legal Range	Default	Required	Variability
	Codes listed above	FUEL	No	constant

whResType=choice

Resistance heater type, valid only if whHeatSrc is equal to RESISTANCEX, else ignored. These choices are supported by the detailed HPWH model. Except for Generic, all heater characteristics are set by HPWH based on whResType.

Units	Legal Range	Default	Required	Variability
	Typical SwingTank	Typical	No	constant

whHeatingCap=float

Nominal heating capacity, available only for a limited HPWH types.

Units	Legal Range	Default	Required	Variability
Btuh	x \(>\) 0	0	No	constant

whVol=float

Storage tank volume. Must be omitted or 0 for instantaneous whTypes. Used by HPWH model (whHeatSrc=RESISTANCEX or whHeatSrc=ASHPX). Required when whHeatSrc=RESISTANCEX or whHeatSrc=ASHPX with whASHPType=GENERIC. For all other configurations, whVol is documentation-only.

Units	Legal Range	Default	Required	Variability
gal	\(\ge\) 0.1 (caution: small values may cause runtime errors)	per whASHPType if HPWH else 50	For some HPWH configurations, see above	constant

whVolRunning=float

Running storage volume is the volume above aquastat. Requires the total volume based on aquastat position. Ecotope’s HPWH tank and heater.

Units	Legal Range	Default	Required	Variability
gal	x \(>\) 0	0	No	constant

whEF=float

Rated energy factor that specifies DHWHEATER efficiency under test conditions. Used by CSE to derive annual water heating efficiency and/or other characteristics as described below. Calculation methods are documented in RACM, Appendix B.

Configuration	whEF default	Use
whType=SMALLSTORAGE, whHeatSrc=RESISTANCE or FUEL	0.82	Derivation of whLDEF
whType=SMALLSTORAGE, whHeatSrc=ASHP	0.82	Derivation of whLDEFnote inappropriate default (deprecated, use ASHPX)
whType=SMALLSTORAGE, whHeatSrc=ASHPX, whASHPType=GENERIC	(req’d)	Tank losses Overall efficiency
whType=SMALLSTORAGE, whHeatSrc=RESISTANCEX	(req’d)	Tank losses Note: maximum whEF=0.98.
whType=SMALLINSTANTANEOUS, whHeatSrc=RESISTANCE or FUEL	0.82	Annual efficiency = whEF*0.92
Any other	(unused)

Units	Legal Range	Default	Required	Variability
	\(>\) 0 Caution: maximum not checked. Unrealistic values will cause runtime errors and/or invalid results	See above	See above	constant

whLDEF=float

Load-dependent energy factor for DHWHEATERs with whType=SMALLSTORAGE and whHeatSrc=FUEL or whHeatSrc=RESISTANCE. If not given, whLDEF is derived using a preliminary simulation activated via DHWSYS wsCalcMode=PRERUN. See RACM Appendix B.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	Calculated via DHWSYS PreRun mechanism	When whType = SMALLSTORAGE and PreRun not used	constant

whUEF=float

Water heater Uniform Energy Factor efficiency rating, used when whType=INSTANTANEOUSUEF.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	none	when whType= INSTANTANEOUSUEF	constant

whAnnualElec=float

Annual electricity use assumed in UEF rating derivation. Used when whType=INSTANTANEOUSUEF.

Units	Legal Range	Default	Required	Variability
kWh	x \(\ge\) 0	none	when whType= INSTANTANEOUSUEF	constant

whAnnualFuel=float

Annual fuel use assumd in UEF rating derivation, used when whType=INSTANTANEOUSUEF.

Units	Legal Range	Default	Required	Variability
therms	x \(\ge\) 0	none	when whType= INSTANTANEOUSUEF	constant

whRatedFlow=float

Maximum flow rate assumed in UEF rating derivation. Used when whType=INSTANTANEOUSUEF.

Units	Legal Range	Default	Required	Variability
gpm	x \(>\) 0	none	when whType= INSTANTANEOUSUEF	constant

whStbyElec=float

Instantaneous water heater standby power (electricity consumed when heater is not operating). Used when whType=INSTANTANEOUSUEF.

Units	Legal Range	Default	Required	Variability
W	x \(\ge\) 0	4	No	constant

whLoadCFwdF=float

Instanteous water heater load carry forward factor – approximate number of hours the heater is allowed to meet water heating demand that is unmet on a 1 minute basis, used when whType=INSTANTANEOUSUEF.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	constant

whZone=znName

Name of zone where water heater is located, used only in detailed HPWH models (whHeatSrc=ASHPX or whHeatSrc=RESISTANCEX), otherwise no effect. Zone conditions are used for tank heat loss calculations. Heat losses from the DHWHEATER are included in the zone heat balance. whZone also provides the default for whASHPSrcZn (see below).

whZone and whTEx cannot both be specified.

Units	Legal Range	Default	Required	Variability
	name of a ZONE	Not in a zone (heat losses discarded)	No	constant

whTEx=float

Water heater surround temperature, used only in detailed HPWH models (whHeatSrc=ASHPX or whHeatSrc=RESISTANCEX), otherwise no effect. When whTEx is specified, tank heat losses are calculated using whTEx and modify tank water temperatures, but the lost heat has no external effect.

whZone and whTEx cannot both be specified.

Units	Legal Range	Default	Required	Variability
oF	x \(\ge\) 0	whZone air temperature if specified, else 70 oF	No	hourly

whASHPType=choice

Air source heat pump type, valid only if whHeatSrc=ASHPX. These choices are supported by the detailed HPWH model. Except for Generic, all heater characteristics are set by HPWH based on whASHPType.

Choice	Specified type
Generic	General generic (parameterized by wh_EF and wh_vol)
AOSmithPHPT60	60 gallon Voltex
AOSmithPHPT80	80 gallon Voltex
AOSmithHPTU50	50 gallon AOSmith HPTU
AOSmithHPTU66	66 gallon AOSmith HPTU
AOSmithHPTU80	80 gallon AOSmith HPTU
AOSmithHPTU80DR	80 gallon AOSmith HPTU (demand reduction variant)
AOSmithCAHP120	120 gallon AOSmith
Sanden40	Sanden 40 gallon CO2 external heat pump
Sanden80	Sanden 80 gallon CO2 external heat pump
Sanden120	Sanden 120 gallon CO2 external heat pump
SandenGS3	Sanden GS3 compressor CO2 external
GE2012	2012 era GeoSpring
GE2014	2014 80 gal GE model run in the efficiency mode
GE2014_80DR	2014 80 gal GE model run in the efficiency mode (demand reduction variant)
GE2014StdMode	2014 50 gal GE run in standard mode
GE2014StdMode80	2014 80 gal GE run in standard mode
RheemHB50	newish Rheem (2014 model?)
RheemHBDR2250	50 gallon, 2250 W resistance Rheem HB Duct Ready
RheemHBDR4550	50 gallon, 4500 W resistance Rheem HB Duct Ready
RheemHBDR2265	65 gallon, 2250 W resistance Rheem HB Duct Ready
RheemHBDR4565	65 gallon, 4500 W resistance Rheem HB Duct Ready
RheemHBDR2280	80 gallon, 2250 W resistance Rheem HB Duct Ready
RheemHBDR4580	80 gallon, 4500 W resistance Rheem HB Duct Ready
Rheem2020Prem40	40 gallon, Rheem 2020 Premium
Rheem2020Prem50	50 gallon, Rheem 2020 Premium
Rheem2020Prem65	65 gallon, Rheem 2020 Premium
Rheem2020Prem80	80 gallon, Rheem 2020 Premium
Rheem2020Build40	40 gallon, Rheem 2020 Builder
Rheem2020Build50	50 gallon, Rheem 2020 Builder
Rheem2020Build65	65 gallon, Rheem 2020 Builder
Rheem2020Build80	80 gallon, Rheem 2020 Builder
RheemPlugInShared40	40 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInShared50	50 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInShared65	65 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInShared80	80 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInDedicated40	40 gal Rheem plug-in 120V dedicated circuit (no resistance elements)
RheemPlugInDedicated50	50 gal Rheem plug-in 120V dedicated circuit (no resistance elements)
Stiebel220E	Stiebel Eltron (2014 model?)
AOSmithSHPT50	AOSmith add’l models (added 3-24-2017)
AOSmithSHPT66	AOSmith add’l models (added 3-24-2017)
AOSmithSHPT80	AOSmith add’l models (added 3-24-2017)
GenericTier1	Generic Tier 1
GenericTier2	Generic Tier 2
GenericTier3	Generic Tier 3
Generic	General generic (parameterized by EF and vol)
UEF2Generic	Experimental UEF=2
WorstCaseMedium	UEF2Generic alias (supports pre-existing test cases)
BasicIntegrated	Typical integrated HPWH
ResTank	Resistance heater (no compressor). Superceded by whHeatSrc=RESITANCEX
ResTankNoUA	Resistance heater (no compressor) with no tank losses. Superseded by whHeatSrc=RESISTANCEX.
AOSmithHPTU80DR	80 gallon AOSmith HPTU with fixed backup setpoint (experimental for demand response testing)
AOSmithSHPT50	50 gal AOSmith SHPT
AOSmithSHPT66	66 gal AOSmith SHPT
AOSmithSHPT80	80 gal AOSmith SHPT
AOSmithHPTS40	40 gal AOSmith HPTS
AOSmithHPTS50	50 gal AOSmith HPTS
AOSmithHPTS66	66 gal AOSmith HPTS
AOSmithHPTS80	80 gal AOSmith HPTS
ColmacCxV5_SP	Colmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA10_SP	Colmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA15_SP	Colmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA20_SP	Colmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA25_SP	Colmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA30_SP	Colmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxV5_MP	Colmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA10_MP	Colmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA15_MP	Colmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA20_MP	Colmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA25_MP	Colmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA30_MP	Colmac CxA-xx modular external HPWHs (multi-pass mode)
NyleC25A_SP	Nyle Cxx external HPWHs (SP = single pass mode)
NyleC60A_SP	Nyle Cxx external HPWHs (SP = single pass mode)
NyleC90A_SP	Nyle Cxx external HPWHs (SP = single pass mode)
NyleC125A_SP	Nyle Cxx external HPWHs (SP = single pass mode)
NyleC185A_SP	Nyle Cxx external HPWHs (SP = single pass mode)
NyleC250A_SP	Nyle Cxx external HPWHs (SP = single pass mode)
NyleC60A_CWP_SP	Nyle Cxx external SP HPWHs with cold weather package
NyleC90A_CWP_SP	Nyle Cxx external SP HPWHs with cold weather package
NyleC125A_CWP_SP	Nyle Cxx external SP HPWHs with cold weather package
NyleC185A_CWP_SP	Nyle Cxx external SP HPWHs with cold weather package
NyleC250A_CWP_SP	Nyle Cxx external SP HPWHs with cold weather package
NyleC60A_MP	Nyle Cxx external HPWHs (MP = multi-pass mode)
NyleC90A_MP	Nyle Cxx external HPWHs (MP = multi-pass mode)
NyleC125A_MP	Nyle Cxx external HPWHs (MP = multi-pass mode)
NyleC185A_MP	Nyle Cxx external HPWHs (MP = multi-pass mode)
NyleC250A_MP	Nyle Cxx external HPWHs (MP = multi-pass mode)
NyleC60A_CWP_MP	Nyle Cxx external MP HPWHs w/ cold weather package
NyleC90A_CWP_MP	Nyle Cxx external MP HPWHs w/ cold weather package
NyleC125A_CWP_MP	Nyle Cxx external MP HPWHs w/ cold weather package
NyleC185A_CWP_MP	Nyle Cxx external MP HPWHs w/ cold weather package
NyleC250A_CWP_MP	Nyle Cxx external MP HPWHs w/ cold weather package
Rheem_HPHD60HNU_MP	Rheem HPHD60 MP external MP HPWHs
Rheem_HPHD60VNU_MP	Rheem HPHD60 MP external MP HPWHs
Rheem_HPHD135HNU_MP	Rheem HPHD135 MP external MP HPWHs
Rheem_HPHD135VNU_MP	Rheem HPHD135 MP external MP HPWHs
Scalable_SP	single pass scalable type for autosized standard design
Scalable_MP	multipass scalable type for autosized standard design
AquaThermAire	Villara AquaThermAire HPWH
GenericUEF217	65-gal tank meeting Federal standard minimum requirement
AWHSTier4Generic40	Any 40-gal tank meeting Advanced Water Heating Specification Tier-4 minimum requirements
AWHSTier4Generic50	Any 50-gal tank meeting Advanced Water Heating Specification Tier-4 minimum requirements
AWHSTier4Generic65	Any 65-gal tank meeting Advanced Water Heating Specification Tier-4 minimum requirements
AWHSTier4Generic80	Any 80-gal tank meeting Advanced Water Heating Specification Tier-4 minimum requirements
BradfordWhiteAeroThermRE2H50	Bradford White 50-gal AeroTherm2023
BradfordWhiteAeroThermRE2H65	Bradford White 65-gal AeroTherm2023
BradfordWhiteAeroThermRE2H80	Bradford White 80-gal AeroTherm2023
LG_APHWC50	LG 50-gal integrated HPWH
LG_APHWC80	LG 580-gal integrated HPWH

Units	Legal Range	Default	Required	Variability
	Codes listed above	none	When whHeatSrc=ASHPX	constant

whASHPSrcZn=znName

Name of zone that serves as heat pump heat source used when whHeatSrc=ASHPX. Heat removed from the zone is added to the heated water and is included in zone heat balance (that is, heat pump operation cools the zone).

whASHPSrcZn and whASHPSrcT cannot both be specified.

Units	Legal Range	Default	Required	Variability
	name of a ZONE	whZoneIf no zone is specified by input or default, heat extracted by ASHP has no effect.	No	constant

whASHPSrcT=float

Heat pump source air temperature used when whHeatSrc=ASHPX. Heat removed from this source is added to the heated water but has no other effect.

whASHPSrcZn and whASHPSrcT cannot both be specified.

The logic to determine the temperature of the heat pump source air is:

        if whASHPSrcT is specified
          use whASHPSrcT
        else if whASHPSRCZn is specified
          use whASHPSrcZn air temp
        else if whZone is specified
          use whZone air temp
        else
          use 70 F

To model a heat pump that uses outdoor air as its heat source, omit whASHPSrcZn and specify whASHPSrcT = $tDbO.

Units	Legal Range	Default	Required	Variability
oF	x \(\ge\) 0	70 oF (used only when whASHPSrcZn and whZone not specified)	No	hourly

whASHPResUse=float

Specifies activation temperature difference for resistance heating, used only when whHeatSrc=ASHPX and whASHPType=GENERIC. Refer to HPWH engineering documentation for model details.

Units	Legal Range	Default	Required	Variability
oC	x \(\ge\) 0	7.22	No	constant

whResHtPwr=float

Specifies resistance upper element power, used only with whHeatSrc=RESISTANCEX.

Units	Legal Range	Default	Required	Variability
W	x \(\ge\) 0	4500	No	constant

whResHtPwr2=float

Specifies resistance lower element power, used only with whHeatSrc=RESISTANCEX.

Units	Legal Range	Default	Required	Variability
W	x \(\ge\) 0	whResHtPwr	No	constant

whUA=float

HPWH-type total UA (not per tank)

Units	Legal Range	Default	Required	Variability
Btuh/F	x \(\geq\) 0	HPWH default	No	constant

whInsulR=float

Tank insulation resistance for heat pump water heater.

Units	Legal Range	Default	Required	Variability
hr-F/Btuh	x \(>\) 0	-1	No	constant

whInHtSupply=float
whInHtLoopRet=float

Fractional tank height of inlets for supply water and DHWLOOP return, used only with HPWH types (whHeatSrc=RESISTANCEX or whHeatSrc=ASHPX). 0 indicates the bottom of the water heater tank and 1 specifies the top. Inlet height influences tank layer mixing and can impact heat pump COP and/or heating activation frequency.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	HPWH default (0?)	No	constant

whtankCount=float

Number of storage tanks per DHWHEATER, re built-up whType=Builtup, does not reflect wh_mult (wh_mult=2, wh_tankCount=3 -> 6 tanks).

Units	Legal Range	Default	Required	Variability
#	x \(\geq\) 1	1	No	constant

whEff=float

Water heating efficiency, used in modeling whType=LARGESTORAGE and whType=LARGEINSTANTANEOUS.

Units	Legal Range	Default	Required	Variability
	0 \(<\) whEff \(\leq\) 1	.82	No	constant

whSBL=float

Standby loss, used in modeling whType=LARGESTORAGE.

Units	Legal Range	Default	Required	Variability
Btuh	x \(\ge\) 0	0	No	constant

whPilotPwr=float

Pilot light consumption, included in fuel energy use of DHWHEATERs with whHeatSrc=FUEL.

Units	Legal Range	Default	Required	Variability
Btuh	x \(\ge\) 0	0	No	hourly

whParElec=float

Parasitic electricity power, included in electrical energy use of all DHWHEATERs.

Units	Legal Range	Default	Required	Variability
W	x \(\ge\) 0	0	No	hourly

whFAdjElec=float
whFAdjFuel=float

Water heater energy use modifiers. Multiplies calculated use of electricity (whFAdjElec) and fuel (whFAdjFuel). All components of energy use – primary, backup, XBU (extra backup), and other auxiliary – are modified before they are accumulated to whElecMtr and whFuelMtr.

Units	Legal Range	Default	Required	Variability
	\(\ge\) 0	1	No	subhourly

whElecMtr=mtrName

Name of METER object, if any, by which DHWHEATER electrical energy use is recorded (under end use DHW).

Units	Legal Range	Default	Required	Variability
	name of a METER	Parent DHWSYS wsElecMtr	No	constant

whxBUEndUse=choice

Specifies the whElecMtr end use, if any, to which extra backup energy is accumulated. In some water heater types, extra backup energy is modeled to maintain output temperature at wsTUse. By default, extra backup energy is included in end use dhwBU. whxBUEndUse allows specification of an alternative end use to which extra backup energy is accumulated.

Units	Legal Range	Default	Required	Variability
	end use code	(extra backup accums to dhwBU)	No	constant

whFuelMtr =mtrName

Name of METER object, if any, by which DHWHEATER fuel energy use is recorded (under end use DHW).

Units	Legal Range	Default	Required	Variability
name of a METER	Parent DHWSYS wsFuelMtr		No	constant

whTankTInit =comma-separated list of 12 floats

A list of 12 initial values for HPWH tank model layer temperatures, in bottom-to-top order. If given, these values are used to initialize tank layer temperatures at the beginning of the warmup period. Initialization is not repeated at the beginning of the main simulation.

whTankTInit is allowed only for HPWH-based types (whHeatSrc=ASHPX or whHeatSrc=ResistanceX).

whTankTInit is intended for use in empirical validation studies where the initial tank state needs to match measured data. whTankTInit should not be generally used. In the absence of whTankTInit, layer temperatures are initialized to the water heater setpoint inherited from the parent DHWSYS.

Units	Legal Range	Default	Required	Variability
oF	x \(\gt\) 0		No	constant

endDHWHEATER

Optionally indicates the end of the DHWHEATER definition.

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 0	none	No

Related Probes:

• @DHWHeater

4.35 DHWHEATREC

DHWHEATREC constructs an object representing one or more heat recovery devices in a DHWSYS. Drain water heat recovered by the device increases parent DHWSYS wsInlet temperature and/or fixture cold water feed temperature. This reduces water heating energy consumption.

wrName

Optional name of device; give after the word “DHWHEATREC” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

wrMult=integer

Number of identical heat recovery devices of this type. Any value >1 is equivalent to repeated entry of the same DHWHEATREC.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

wrHWEndUse=choice

Hot water end use to which this DHWHEATREC is applied: one of Shower, Bath, CWashr, DWashr, or Faucet. Selects DHWUSE draws for heat recovery calculations. Currently, only Shower is supported.

Units	Legal Range	Default	Required	Variability
	Shower	Shower	No	constant

wrCountFXDrain=integer

Number of fixtures (of type wrHWEndUse) whose drain lines pass through this heat recovery device. wrCountFXDrain=0 causes this DHWHEATREC to have no effect (that is, equivalent to omitting the DHWHEATREC command).

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	constant

wrCountFXCold=integer

Number of fixtures (of type wrHWEndUse) with cold water supply connected to the DHWHEATREC potable-side outlet and thus use tempered water to mix with hot water.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	constant

wrFeedsWH=choice

Specifies whether the potable-side outlet of the DHWHEATREC is connected to the DHWHEATER(s) inlet.

Units	Legal Range	Default	Required	Variability
	Yes, No	No	No	constant

wrType=choice

Specifies the type of heat recovery device: Vertical, Horizontal, or SetEF. Horizontal and Vertical derive effectiveness from wrCSARatedEF, flow rates, and water temperatures. As of Feb. 2019, the same correlation is used for both Horizontal and Vertical, so these choices have no effect on results. Choice SetEF uses wrCSARatedEF without modification as the effectiveness (note hourly variability).

Units	Legal Range	Default	Required	Variability
	Vertical, Horizontal, SetEF	Vertical	No	constant

wrCSARatedEF=float

Specifies the heat recovery effectiveness, generally determined using CSA B55.2 rating conditions. This value is modified during simulation based on water flow rates and temperatures. If wrType=SetEF, wsCSARatedEF is used without modification.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	none	Yes	hourly

wrTDInDiff=float

Temperature drop between the fixture drain and DHWHEATREC drain-side inlet. The drain-side inlet temperature is thus DHWUSE wuTemp - wrTDInDiff.

Units	Legal Range	Default	Required	Variability
oF	x \(\ge\) 0	4.6 oF	No	hourly

wrTDInWarmup=float

Drain-side inlet water temperature during warmup. During the warmup portion of a draw (if any), the drain-side inlet temperature will initially be lower than that based on DHWUSE wuTemp. wrTDInWarmup allows input of user estimates for this temperature. Note wrTDInWarmup is not adjusted by wrTDInDiff.

Units	Legal Range	Default	Required	Variability
oF	x \(>\) 0	65 oF	No	hourly

endDHWHEATREC

Optionally indicates the end of the DHWHEATREC definition.

Units	Legal Range	Default	Required	Variability
		none	No

Related Probes:

4.36 DHWTANK

DHWTANK constructs an object representing one or more unfired water storage tanks in a DHWSYS. DHWTANK heat losses contribute to the water heating load.

wtName

Optional name of tank; give after the word “DHWTANK” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

wtMult=integer

Number of identical tanks of this type. Any value \(>1\) is equivalent to repeated entry of the same DHWTANK.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

Tank heat loss is calculated hourly (note that default heat loss is 0) –

\[\text{qLoss} = \text{wtMult} \cdot (\text{wtUA} \cdot (\text{wtTTank} - \text{wtTEx}) + \text{wtXLoss})\]

wtUA=float

Tank heat loss coefficient.

Units	Legal Range	Default	Required	Variability
Btuh/oF	x \(\ge\) 0	Derived from wtVol and wtInsulR	No	constant

wtVol=float

Specifies tank volume.

Units	Legal Range	Default	Required	Variability
gal	x \(\ge\) 0	0	No	constant

wtInsulR=float

Specifies total tank insulation resistance. The input value should represent the total resistance from the water to the surroundings, including both built-in insulation and additional exterior wrap insulation.

Units	Legal Range	Default	Required	Variability
ft2-oF/Btuh	x \(\ge\) 0.01	0	No	constant

wtZone=znName

Zone location of DHWTANK regarding tank loss. The value of zero only valid if wtTEx is being used. Half of the heat losses go to zone air and the other goes to half radiant.

Units	Legal Range	Default	Required	Variability
	Name of ZONE	0	No	constant

wtTEx=float

Tank surround temperature.

Units	Legal Range	Default	Required	Variability
oF	x \(\ge\) 0	70	No	hourly

wtTTank=float

Tank average water temperature.

Units	Legal Range	Default	Required	Variability
oF	\(>\) 32 oF	Parent DHWSYSTEM wsTUse	No	hourly

wtXLoss=float

Additional tank heat loss. To duplicate CEC 2016 procedures, this value should be used to specify the fitting loss of 61.4 Btuh.

Units	Legal Range	Default	Required	Variability
Btuh	(any)	0	No	hourly

endDHWTank

Optionally indicates the end of the DHWTANK definition.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @DHWTank

4.37 DHWPUMP

DHWPUMP constructs an object representing a domestic hot water circulation pump (or more than one if identical).

wpName

Optional name of pump; give after the word “DHWPUMP” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

wpMult=integer

Number of identical pumps of this type. Any value \(>1\) is equivalent to repeated entry of the same DHWPUMP.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

wpPwr=float

Pump power.

Units	Legal Range	Default	Required	Variability
W	x \(>\) 0	0	No	hourly

wpElecMtr=mtrName

Name of METER object, if any, to which DHWPUMP electrical energy use is recorded (under end use DHW).

Units	Legal Range	Default	Required	Variability
	name of a METER	Parent DHWSYS wsElecMtr	No	constant

endDHWPump

Optionally indicates the end of the DHWPUMP definition.

Units	Legal Range	Default	Required	Variability
		none	No

Related Probes:

• @DHWPump

4.38 DHWLOOP

DHWLOOP constructs one or more objects representing a domestic hot water circulation loop. The actual pipe runs in the DHWLOOP are specified by any number of DHWLOOPSEGs (see below). Circulation pumps are specified by DHWLOOPPUMPs (also below).

wlName

Optional name of loop; give after the word “DHWLOOP” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

wlMult=integer

Number of identical loops of this type. Any value \(>1\) is equivalent to repeated entry of the same DHWLOOP (and all child objects).

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

wlFlow=float

Loop flow rate (when operating).

Units	Legal Range	Default	Required	Variability
gpm	x \(\ge\) 0	6	No	hourly

wlTIn1=float

Inlet temperature of first DHWLOOPSEG.

Units	Legal Range	Default	Required	Variability
oF	x \(>\) 0	DHWSYS wsTUse	No	hourly

wlRunF=float

Fraction of hour that loop circulation operates.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	hourly

wlFUA=float

DHWLOOPSEG pipe heat loss adjustment factor. DHWLOOPSEG UA is derived (from wgSize, wgLength, wgInsulK, wgInsulThk, and wgExH) and multiplied by wlFUA. Note: does not apply to child DHWLOOPBRANCHs (see wbFUA).

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

wlLossMakeupPwr=float

Specifies electrical power available to make up losses from DHWLOOPSEGs (loss from DHWLOOPBRANCHs is not included). Separate loss makeup is typically used in multi-unit HPWH systems to avoid inefficiencies associated with high condenser temperatures. Loss-makeup energy is calculated hourly and is the smaller of loop losses and wlLossMakeupPwr. The resulting electricity use (including the effect of wlLossMakeupEff) is accumulated to the METER specified by wlElecMtr (end use dhwMFL). No other effect, such as heat gain to surroundings, is modeled.

Units	Legal Range	Default	Required	Variability
W	x \(\ge\) 0	0	No	hourly

wlLossMakeupEff=float

Specifies the efficiency of loss makeup heating if any. No effect when wlLossMakeupPwr is 0.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	hourly

wlElecMtr=mtrName

Name of METER object, if any, to which DHWLOOP electrical energy use is recorded (under end use dhwMFL).

Units	Legal Range	Default	Required	Variability
	name of a METER	Parent DHWSYS wsElecMtr	No	constant

endDHWLoop

Optionally indicates the end of the DHWLOOP definition.

Units	Legal Range	Default	Required	Variability
		none	No

Related Probes:

• @DHWLoop

4.39 DHWLOOPPUMP

DHWLOOPPUMP constructs an object representing a pump serving part a DHWLOOP. The model is identical to DHWPUMP except that that the electricity use calculation reflects wlRunF of the parent DHWLOOP.

wlpName

Optional name of pump; give after the word “DHWLOOPPUMP” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

wlpMult=integer

Number of identical pumps of this type. Any value \(>1\) is equivalent to repeated entry of the same DHWPUMP.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

wlpPwr=float

Pump power.

Units	Legal Range	Default	Required	Variability
W	x \(>\) 0	0	No	hourly

wlpLiqHeatF=float

Fraction of pump power that heats circulating liquid. The remainder is discarded.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 1	1	No	hourly

wlpElecMtr=mtrName

Name of METER object, if any, to which DHWLOOPPUMP electrical energy use is recorded (under end use dhwMFL).

Units	Legal Range	Default	Required	Variability
	name of a METER	Parent DHWLOOP wlElecMtr	No	constant

endDHWLOOPPUMP

Optionally indicates the end of the DHWPUMP definition.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @DHWLoopPump

4.40 DHWLOOPSEG

DHWLOOPSEG constructs one or more objects representing a segment of the preceeding DHWLOOP. A DHWLOOP can have any number of DHWLOOPSEGs to represent the segments of the loop with possibly differing sizes, insulation, or surrounding conditions.

wgName

Optional name of segment; give after the word “DHWLOOPSEG” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

wgTy=choice

Specifies the type of segment. RETURN segments, if any, must follow SUPPLY segments.

SUPPLY	Indicates a supply segment (flow is sum of circulation and draw flow, child DHWLOOPBRANCHs permitted).
RETURN	Indicates a return segment (flow is only due to circulation, child DHWLOOPBRANCHs not allowed)

Units	Legal Range	Default	Required	Variability
		none	Yes	constant

wgLength=float

Length of segment.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	constant

wgSize=float

Nominal size of pipe. CSE assumes the pipe outside diameter = size + 0.125 in.

Units	Legal Range	Default	Required	Variability
in	x \(>\) 0	1	Yes	constant

wgInsulK=float

Pipe insulation conductivity

Units	Legal Range	Default	Required	**Variability
Btuh-ft/ft2-oF	x \(>\) 0	0.02167	No	constant

wgInsulThk=float

Pipe insulation thickness

Units	Legal Range	Default	Required	Variability
in	x \(\ge\) 0	1	No	constant

wgExH=float

Combined radiant/convective exterior surface conductance between insulation (or pipe if no insulation) and surround.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	1.5	No	hourly

wgExT=float

Surrounding equivalent temperature.

Units	Legal Range	Default	Required	Variability
oF	x \(>\) 0	70	No	hourly

wgFNoDraw=float

Fraction of hour when no draw occurs.

Units	Legal Range	Default	Required	Variability
oF	x \(>\) 0	70	No	hourly

endDHWLoopSeg

Optionally indicates the end of the DHWLOOPSEG definition.

Units	Legal Range	Default	Required	Variability
		none	No

Related Probes:

• @DHWLoopSeg

4.41 DHWLOOPBRANCH

DHWLOOPBRANCH constructs one or more objects representing a branch pipe from the preceding DHWLOOPSEG. A DHWLOOPSEG can have any number of DHWLOOPBRANCHs to represent pipe runs with differing sizes, insulation, or surrounding conditions.

wbName

Optional name of segment; give after the word “DHWLOOPBRANCH” if desired.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

wbMult=float

Specifies the number of identical DHWLOOPBRANCHs. Note may be non-integer.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1	No	constant

wbLength=float

Length of branch.

Units	Legal Range	Default	Required	Variability
ft	x \(\ge\) 0	0	No	constant

wbSize=float

Nominal size of pipe. CSE assumes the pipe outside diameter = size + 0.125 in.

Units	Legal Range	Default	Required	Variability
in	x \(>\) 0	none	Yes	constant

wbInsulK=float

Pipe insulation conductivity

Units	Legal Range	Default	Required	**Variability
Btuh-ft/ft2-oF	x \(>\) 0	0.02167	No	constant

wbInsulThk=float

Pipe insulation thickness

Units	Legal Range	Default	Required	Variability
in	x \(\ge\) 0	1	No	constant

wbExH=float

Combined radiant/convective exterior surface conductance between insulation (or pipe if no insulation) and surround.

Units	Legal Range	Default	Required	Variability
Btuh/ft2-oF	x \(>\) 0	1.5	No	hourly

wbExCnd=choice

Specify exterior conditions.

Choice	Description
ADIABATIC	Adiabatic on other side
AMBIENT	Ambient exterior
SPECT	Specify temperature
ADJZN	Adjacent zone
GROUND	Ground conditions

Units	Legal Range	Default	Required	Variability
	See table above	SPECT	No	constant

wbAdjZn=float

Boundary conditions for adjacent zones.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.0	No	runly

wbExTX=float

External boundary conditions.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	70.0	No	runly

wbFUA=float

Adjustment factor applied to branch UA. UA is derived (from wbSize, wbLength, wbInsulK, wbInsulThk, and wbExH) and then multiplied by wbFUA. Used to represent e.g. imperfect insulation. Note that parent DHWLOOP wlFUA does not apply to DHWLOOPBRANCH (only DHWLOOPSEG)

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	1	No	constant

wbExT=float

Surrounding equivalent temperature.

Units	Legal Range	Default	Required	Variability
oF	x \(>\) 0	70	No	hourly

wbFlow=float

Branch flow rate assumed during draw.

Units	Legal Range	Default	Required	Variability
gpm	x \(\ge\) 0	2	No	hourly

wbFWaste=float

Number of times during the hour when the branch volume is discarded.

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	0	No	hourly

endDHWLOOPBRANCH

Optionally indicates the end of the DHWLOOPBRANCH definition.

Units	Legal Range	Default	Required	Variability
	none	none	No

Related Probes:

• @DHWLoopBranch

4.42 DHWSOLARSYS

Solar water heating system.

• DHWSOLARSYS
  • DHWSOLARCOLLECTOR
  • DHWSOLARTANK

May have any number of solar collectors, but only one tank.

May have no tank for direct system? What if system has multiple primary tanks?

swElecMtr=mtrName

Name of METER object, if any, to which DHWSOLARSYS electrical energy use is recorded (under end use ???).

Units	Legal Range	Default	Required	Variability
oF	name of a METER	not recorded	No	constant

swSCFluidSpHt=float

Specific heat for the collector fluid.

Units	Legal Range	Default	Required	Variability
Btu/lbm-oF	x \(>\) 0	0.9	No	constant

swSCFluidDens=float

Density for the collector fluid.

Units	Legal Range	Default	Required	Variability
lb/ft3	x \(>\) 0	64.0	No	constant

swEndUse

End use of pump energy; defaults to “DHW”.

swParElec=float

Units	Legal Range	Default	Required	Variability
	x \(\ge\) 0	0	No	hourly

swTankHXEff=float

Tank heat exchanger effectiveness.

Units	Legal Range	Default	Required	Variability
	0 \(\le\) x \(\le\) 0.99	0	No	hourly

swTankTHxLimit=float

Temperature limit for the tank collector.

Units	Legal Range	Default	Required	Variability
oF	x \(\geq\) 0	180.0	No	constant

swTankUA=float

Heat transfer coefficient for the tank multiplied by area.

Units	Legal Range	Default	Required	Variability
Btuh/oF			No	constant

swTankVol=float

Units	Legal Range	Default	Required	Variability
gal			No	constant

swTankInsulR=float

Total tank insulation resistance, built-in plus exterior wrap.

Units	Legal Range	Default	Required	Variability
ft2-oF/Btuh			No	constant

swTankZone=znName

Pointer to tank zone location, use sw_tankTEx if NULL

Units	Legal Range	Default	Required	Variability
	Name of ZONE		No	constant

swTankTEx=float

Surrounding temperature.

Units	Legal Range	Default	Required	Variability
oF			No	hourly

endDHWSOLARSYS

Optionally indicates the end of the DHWSOLARSYS definition.

Units	Legal Range	Default	Required	Variability
		none	No

4.43 DHWSOLARCOLLECTOR

Solar Collector Array. May be multiple collectors on the same DHWSOLARSYS system. All inlets come from the DHWSOLARTANK.

Uses SRCC Ratings.

scArea=float

Collector area.

Units	Legal Range	Default	Required	Variability
ft^2	\(>\) 0	0	Yes	constant

scMult

Number of identical collectors, default 1

Units	Legal Range	Default	Required	Variability
	\(>\) 0	1	No	constant

scTilt=float

Array tilt.

Units	Legal Range	Default	Required	Variability
deg		0	Yes	constant

scAzm=float

Array azimuth.

Units	Legal Range	Default	Required	Variability
deg		0	Yes	constant

scFRUL=float

Fit slope

Units	Legal Range	Default	Required	Variability
Btuh/ft2-o^F		-0.727	No	constant

scFRTA=float

Fit y-intercept

Units	Legal Range	Default	Required	Variability
none	\(>\) 0	0.758	No	constant

scTestMassFlow=flaot

Mass flow rate for collector loop SRCC rating.

Units	Legal Range	Default	Required	Variability
lb/h-ft2	x \(>\) 0	14.79	No	constant

scKta60=float

Incident angle modifier at 60 degree, from SRCC rating.

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 0	0.72	No	constant

scOprMassFlow=float

Collector loop operating mass flow rate.

Units	Legal Range	Default	Required	Variability
lb/h-ft2	x \(>\) 0	0.0	No	constant

scPipingLength=float

Collector piping length.

Units	Legal Range	Default	Required	Variability
ft	x \(\geq\) 0	0.0	No	Hourly and at the end of interval

scPipingInsulK=float

Collector piping insulation conductivity.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	0.02167	No	Hourly and at the end of interval

scPipingInsulThk=float

Collector piping insulation thickness.

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 0	1.0	No	Hourly and at the end of interval

scPipingExH=float

Collector piping heat transfer coefficient.

Units	Legal Range	Default	Required	Variability
	x \(>\) 0	1.5	No	Hourly and at the end of interval

scPipingExT=float

Collector piping surround temperature.

Units	Legal Range	Default	Required	Variability
oF	x \(\geq\) 32	70.0	No	hourly

scPumpPwr=float

Units	Legal Range	Default	Required	Variability
Btu/h	x \(\ge\) 0	from scPumpflow	No	constant

scPumpLiqHeatF=float

Fraction of scPumpPwr added to liquid stream, the remainder is discarded.

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 0	1.0	No	Every run

scPumpOnDeltaT=float

Temperature difference between the tank and collector outlet where pump turns on

Units	Legal Range	Default	Required	Variability
oF		10.0	No	constant

scPumpOffDeltaT=float

Temperature difference between the tank and collector outlet where pump turns off

Units	Legal Range	Default	Required	Variability
oF		5.0	No	constant

endDHWSOLARCOLLECTOR

Optionally indicates the end of the DHWSOLARCOLLECTOR definition.

Units	Legal Range	Default	Required	Variability
		none	No

4.44 PVARRAY

PVARRAY describes a photovoltaic panel system. The algorithms are based on the PVWatts calculator.

pvName

Name of photovoltaic array. Give after the word PVARRAY.

Units	Legal Range	Default	Required	Variability
	63 characters	none	No	constant

pvElecMtr=choice

Name of meter by which this PVARRAY’s AC power out is recorded. Generated power is expressed as a negative value.

Units	Legal Range	Default	Required	Variability
	name of a METER	none	No	constant

pvEndUse=choice

Meter end use to which the PVARRAY’s generated energy should be accumulated.

Clg	Cooling
Htg	Heating (includes heat pump compressor)
HPBU	Heat pump resistance heating (backup and defrost)
DHW	Domestic (service) hot water
DHWBU	Domestic (service) hot water heating backup (HPWH resistance)
DHWMFL	Domestic (service) hot water heating multi-family loop pumping and loss makeup
FANC	Fans, AC and cooling ventilation
FANH	Fans, heating
FANV	Fans, IAQ venting
FAN	Fans, other purposes
AUX	HVAC auxiliaries such as pumps
PROC	Process
LIT	Lighting
RCP	Receptacles
EXT	Exterior lighting
REFR	Refrigeration
DISH	Dishwashing
DRY	Clothes drying
WASH	Clothes washing
COOK	Cooking
USER1	User-defined category 1
USER2	User-defined category 2
BT	Battery charge power
PV	Photovoltaic power generation

Units	Legal Range	Default	Required	Variability
	Codes listed above	PV	No	constant

pvDCSysSize=float

The rated photovoltaic system DC capacity/size as indicated by the nameplate.

Units	Legal Range	Default	Required	Variability
kW	x \(\geq\) 0	none	Yes	constant

pvModuleType=choice

Type of module to model. The module type determines the refraction index and temperature coefficient used in the simulation. Alternatively, the “Custom” module type may be used in conjunction with user-defined input for pvCoverRefrInd and pvTempCoeff.

Module Type	pvCoverRefrInd	pvTempCoeff
Standard	1.3	-0.00206
Premium	1.3	-0.00194
ThinFilm	1.3	-0.00178
Custom	User-defined	User-defined

Units	Legal Range	Default	Required	Variability
	Standard Premium ThinFilm Custom	Standard	No	constant

pvCoverRefrInd=float

The refraction index for the coating applied to the module cover. A value of 1.0 represents refraction through air. Coatings have higher refraction indexes that capture more solar at lower angles of incidence.

Units	Legal Range	Default	Required	Variability
	x \(\geq\) 0	1.3	No	constant

pvTempCoeff=float

The temperature coefficient how the efficiency of the module varies with the cell temperature. Values are typically negative.

Units	Legal Range	Default	Required	Variability
1/oF	no restrictions	-0.00206	No	constant

pvArrayType=choice

The type of array describes mounting and tracking options. Roof mounted arrays have a higher installed nominal operating cell temperature (INOCT) of 120 ^oF compared to the default of 113 ^oF. Array self-shading is not currently calculated for adjacent rows of modules within an array.

Units	Legal Range	Default	Required	**Variability
	FixedOpenRack, FixedRoofMount, OneAxisTracking, TwoAxisTracking	FixedOpenRack	No	constant

pvTilt=float

The tilt of the photovoltaic array from horizontal. Values outside the range 0 to 360 are first normalized to that range. For one-axis tracking, defines the tilt of the rotation axis. Not used for two-axis tracking arrays. Should be omitted if pvVertices is given.

Units	Legal Range	Default	Required	Variability
degrees	unrestricted	from pvVertices (if given) else 0	No	hourly

The following figures illustrate the use of both pvTilt and pvAzm for various configurations:

pvAzm=float

Photovoltaic array azimuth (0 = north, 90 = east, etc.). If a value outside the range 0^o \(\leq\) x \(<\) 360^o is given, it is normalized to that range. For one-axis tracking, defines the azimuth of the rotation axis. Not used for two-axis tracking arrays. Should be omitted if pvVertices is given.

Units	Legal Range	Default	Required	Variability
degrees	unrestricted	from pvVertices (if given) else 0	No	hourly

pvVertices=list of up to 36 floats

Vertices of an optional polygon representing the position and shape of the photovoltaic array. The polygon is used to calculate the shaded fraction using an advanced shading model. Only PVARRAYs and SHADEXs are considered in the advanced shading model – PVARRAYs can be shaded by SHADEXs or other PVARRAYs. If pvVertices is omitted, the PVARRAY is assumed to be unshaded at all times. Advanced shading must be enabled via TOP exShadeModel. Note that the polygon is used only for evaluating shading; array capacity is specified by pvDCSysSize (above).

The values that follow pvVertices are a series of X, Y, and Z values for the vertices of the polygon using a coordinate system defined from a viewpoint facing north. X and Y values convey east-west and north-south location respectively relative to an arbitrary origin (positive X value are to the east; positive Y values are to the north). Z values convey height relative to the building 0 level and positive values are upward.

The vertices are specified in counter-clockwise order when facing the receiving surface of the PVARRAY. The number of values provided must be a multiple of 3. The defined polygon must be planar and have no crossing edges. When pvMounting=Building, the effective position of the polygon is modified in response to building rotation specified by TOP bldgAzm.

For example, to specify a rectangular photovoltaic array that is 10 x 20 ft, tilted 45 degrees, and facing south –

 pvVertices = 0, 0, 15,   20, 0, 15,  20, 7.07, 22.07,  0, 7.07, 22.07

Units	Legal Range	Default	Required	Variability
ft	unrestricted	no polygon	9, 12, 15, 18, 21, 24, 27, 30, 33, or 36 values	constant

pvSIF=float

Shading Impact Factor (SIF) of the array used to represent the disproportionate impact on array output of partially shaded modules at the sub-array level. This impact is applied to the effective beam irradiance on the array:

\[I_{poa,beam,eff} = \max\left(I_{poa,beam}\cdot\left(1-SIF\cdot f_{sh}\right),0\right)\]

where \(f_{sh}\) is the fraction of the array that is shaded.

Default value is 1.2, which is representative of PV systems with sub-array microinverters or DC power optimizers. For systems without sub-array power electronics, values are closer to 2.0.

Units	Legal Range	Default	Required	Variability
–	x \(\geq\) 1.0	1.2	No	constant

pvMounting=choice

Specified mounting location of this PVARRAY. pvMounting=Site indicates the array position is not altered by building rotation via TOP bldgAzm, while PVARRAYs with pvMounting=Building are assumed to rotate with the building.

Units	Legal Range	Default	Required	Variability
	Building or Site	Building	No	constant

pvGrndRefl=float

Ground reflectance used for calculating reflected solar incidence on the array.

Units	Legal Range	Default	Required	Variability
	0 \(<\) x \(<\) 1.0	0.2	No	hourly

pvDCtoACRatio=float

DC-to-AC ratio used to intentionally undersize the AC inverter. This is used to increase energy production in the beginning and end of the day despite the possibility of clipping peak sun hours.

Units	Legal Range	Default	Required	Variability
	x > 0.0	1.2	No	constant

pvInverterEff=float

AC inverter efficiency at rated DC power.

Units	Legal Range	Default	Required	Variability
	0 \(<\) x \(<\) 1.0	0.96	No	constant

pvSysLosses=float

Fraction of total DC energy lost. The total loss from a system is aggregated from several possible causes as illustrated below:

Loss Type	Default Assumption
Soiling	0.02
Shading	0 (handled explicitly)
Snow	0
Mismatch	0 (shading mismatch handled explicitly [see pvSIF])
Wiring	0.02
Connections	0.005
Light-induced degradation	0.015
Nameplate rating	0.01
Age	0.05 (estimated 0.5% degradation over 20 years)
Availability	0.03
Total	0.14

Italic lines indicate differences from PVWatts assumptions.

Units	Legal Range	Default	Required	Variability
	0 \(<\) x \(<\) 1.0	0.14	No	hourly

endPVARRAY

Optionally indicates the end of the PVARRAY definition. Alternatively, the end of the definition can be indicated by END or by beginning another object.

Units	Legal Range	Default	Required	Variability
		none	No	constant

Related Probes:

• @PVArray