CSE User's Manual

California Simulation Engine

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:

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:

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:

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:

floatA 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.
intAn 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).
BooleanSame as int; indicates that a 0 value will be interpreted as “false” and any non-0 value will be interpreted as “true”.
stringA string of characters; for example, some text enclosed in quotes.
object nameName 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.
choiceOne 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.
dateMay 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:

numericfloat or int. When floats and ints are intermixed with the same operator or function, the result is float.
anyTypeAny 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.

intoptional - 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’).
floatoptional - 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 inchesFeet 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 nameSame 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.
choiceSame as string; quotes optional on choice words valid for the member. Capitalization does not matter.
dateJulian 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.

OperatorNameNotes and Examples
Feet-Inches Separatora ’ b yields a + b/12; thus 4’6 = 4.5.
+Unary plusThe familiar “positive”, as in +3. Does nothing; rarely used.
-Unary minusThe familiar “minus”, as in -3. -(-3) = +3 etc.
!Logical NOTChanges 0 to 1 and any non-0 value to 0. !0 = 1, !17 = 0.
~One’s complementComplements each bit in an int value.
*MultiplicationMultiplication, e.g. 3*4 = 12; 3.24*18.54 = 60.07
/DivisionDivision, 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!
%ModulusYields 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).
+AdditionYields the sum of the operands, e.g. 5+3 = 8
-SubtractionYields the difference of the operands, e.g. 5-3 = 2
>>Right shifta >> b yields a shifted right b bit positions, e.g. 8>>2 = 2
<<Left shifta << b yields a shifted left b bit positions, e.g. 8<<2 = 32
<Less thana < b yields 1 if a is less than b, otherwise 0
<=Less than or equala <= b yields 1 if a is less than or equal to b, otherwise 0
>=Greater than or equala >= b yields 1 if a is greater than or equal to b, otherwise 0
>Greater thana > b yields 1 if a is greater than b, otherwise 0
==Equala == b yields 1 if a is exactly (bit wise) equal to b, otherwise 0
!=Not equala != b yields 1 if a is not equal to b, otherwise 0
&Bitwise anda & b yields the bitwise AND of the operands, e.g. 6 & 2 = 2.
^Bitwise exclusive ora ^ b yields the bitwise XOR of the operands, e.g. 6 ^ 2 = 4.
|Bitwise inclusive ora | b yields the bitwise IOR of the operands, e.g. 6 | 2 = 6.
&&Logical ANDa && 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 ORa || 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.
? :Conditionala ? 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.)

$dayOfYearDay 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.
$monthMonth of year, 1 - 12. Variation: monthly.
$dayOfMonthDay of month, 1 - 31. Variation: daily.
$hourHour of day, 1 - 24, in local time; 1 corresponds to midnight - 1 AM. Variation: hourly.
$hourSTHour of day, 1 - 24, in standard time; 1 corresponds to midnight - 1 AM. Variation: hourly.
$subhourSubhour of hour, 1 - N (number of subhours). Variation: subhourly.
$dayOfWeekDay of week, 1 - 7; 1 corresponds to Sunday, 2 to Monday, etc. Variation: daily.
$DOWHDay of week 1-7 except 8 on every observed holiday. Variation: daily.
$isHoliday1 on days that a holiday is observed (regardless of the true date of the holiday); 0 on other days. Variation: daily.
$isHoliTrue1 on days that are the true date of a holiday, otherwise 0. Variation: daily.
$isWeHol1 on weekend days or days that are observed as holidays. Variation: daily.
$isWeekend1 on Saturday and Sunday, 0 on any day from Monday to Friday. Variation: daily.
$isWeekday1 on Monday through Friday, 0 on Saturday and Sunday. Variation: daily.
$isBegWeek1 for any day immediately following a weekend day or observed holiday that is neither a weekend day or an observed holiday. Variation: daily.
$isWorkDay1 on non-holiday Monday through Friday, 0 on holidays, Saturday and Sunday. Variation: daily.
$isNonWorkDay1 on Saturday, Sunday and observed holidays, 0 on non-holiday Monday through Friday. Variation: daily.
$isBegWorkWeek1 on the first workday after a non-workday, 0 all other days. Variation: daily.
$isDT1 if Daylight Saving time is in effect, 0 otherwise. Variation: hourly.
$autoSizing1 during autosizing calculations, 0 during main simulation. Variation: for each phase.
$dsDayDesign 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.

$radBeamSolar beam irradiance (on a sun-tracking surface) this hour (Btu/ft2)
$radDiffSolar diffuse irradiance (on horizontal surface) this hour (Btu/ft2)
$tDbOOutdoor drybulb temperature this hour (degrees F)
$tWbOOutdoor wetbulb temperature this hour (degrees F)
$wOOutdoor humidity ratio this hour (lb H2O/lb dry air)
$windDirDegWind direction (compass degrees)
$windSpeedWind 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

Functionlimits a value to be in a given range
Syntaxnumeric brkt( numeric min, numeric val, numeric max)
RemarkIf val is less than min, returns min; if val is greater than max, returns max; if val is in between, returns val.
ExampleIn 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

Functionconverts float to int
Syntaxint fix( float val )
Remarkval 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

Functionconverts int to float
Syntaxfloat toFloat( int val )

3.6.5.4 min

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

3.6.5.5 max

Functionreturns the highest quantity from a list of values.
Syntaxnumeric max ( numeric value1, numeric value2,numeric valuen )

3.6.5.6 choose

Functionreturns the nth value from a list. If arg0 is 0, value0 is returned; for 1, value1 is returned, etc.
SyntaxanyType choose ( int arg0, anyType value0, anyType value1, … anyType valuen ) or anyType choose ( int arg0, anyType value0, … anyType valuen, default valueDef)
RemarksAny 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

Functionsame as choose except arg0 is 1-based. Choose1 returns the second argument value1 for arg0 = 1, the third argument value2 when arg0 = 2, etc.
SyntaxanyType choose1 ( int arg0, anyType value1, anyType value2, … anyType valuen ) or anyType choose1 ( int arg0, anyType value1,anyType valuen, default valueDef)
Remarkschoose1 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

Functioncontains Boolean-value pairs; returns the value associated with the first Boolean that evaluates to true (non-0).
SyntaxanyType ( Boolean arg1, anyType value1, Boolean arg2, anyType value2, … default anyType) (the default part is optional)
Remarkselect 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)) ).
ExamplesSelect 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

Functionfrom a list of 24 values, returns the value corresponding to the hour of day.
SyntaxanyType hourval ( anyType value1, anyType value2,anyType value24 )
anyType hourval ( anyType value1, anyType value2, … default anyType)
Remarkhourval 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.
Examplesee select, just above.

3.6.5.10 abs

Functionconverts numeric to its absolute value
Syntaxnumeric abs( numeric val)

3.6.5.11 sqrt

FunctionCalculates and returns the positive square root of val ( val must be \(\geq\) 0).
Syntaxfloat sqrt ( float val)

3.6.5.12 exp

FunctionCalculates and returns the exponential of val (= eval)
Syntaxfloat exp( float val)

3.6.5.13 logE

FunctionCalculates and returns the base e logarithm of val ( val must be \(\geq\) 0).
Syntaxfloat logE( float val)

3.6.5.14 log10

FunctionCalculates and returns the base 10 logarithm of val ( val must be \(\geq\) 0).
Syntaxfloat log10( float val)

3.6.5.15 sin

FunctionCalculates and returns the sine of val (val in radians)
Syntaxfloat sin( float val)

3.6.5.16 sind

FunctionCalculates and returns the sine of val (val in degrees)
Syntaxfloat sind( float val)

3.6.5.17 asin

FunctionCalculates and returns (in radians) the arcsine of val
Syntaxfloat asin( float val)

3.6.5.18 asind

FunctionCalculates and returns (in degrees) the arcsine of val
Syntaxfloat asind( float val)

3.6.5.19 cos

FunctionCalculates and returns the cosine of val (val in radians)
Syntaxfloat cos( float val)

3.6.5.20 cosd

FunctionCalculates and returns the cosine of val (val in degrees)
Syntaxfloat cosd( float val)

3.6.5.21 acos

FunctionCalculates and returns (in radians) the arccosine of val
Syntaxfloat acos( float val)

3.6.5.22 acosd

FunctionCalculates and returns (in degrees) the arccosine of val
Syntaxfloat acosd( float val)

3.6.5.23 tan

FunctionCalculates and returns the tangent of val (val in radians)
Syntaxfloat tan( float val)

3.6.5.24 tand

FunctionCalculates and returns the tangent of val (val in degrees)
Syntaxfloat tand( float val)

3.6.5.25 atan

FunctionCalculates and returns (in radians) the arctangent of val
Syntaxfloat atan( float val)

3.6.5.26 atand

FunctionCalculates and returns (in degrees) the arctangent of val
Syntaxfloat atand( float val)

3.6.5.27 atan2

FunctionCalculates and returns (in radians) the arctangent of y/x (handling x = 0)
Syntaxfloat atan2( float y, float x)

3.6.5.28 atan2d

FunctionCalculates and returns (in degrees) the arctangent of y/x (handling x = 0)
Syntaxfloat atan2d( float y, float x)

3.6.5.29 pow

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

3.6.5.30 enthalpy

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

3.6.5.31 wFromDbWb

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

3.6.5.32 wFromDbRh

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

3.6.5.33 rhFromDbW

FunctionReturns relative humidity (0 – 1) of moist air from dry bulb temperature (F) and humidity ratio (lb/lb).
Syntaxfloat rhFromDbW( float tDb, float w)
RemarkThe 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

FunctionReturns float read from an import file.
Syntaxfloat import( string importFile, string colName)
float import( string importFile, int colN)
RemarkColumns 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.
Syntaxstring importStr( string importFile, string colName)
string importStr( string importFile, int colN)
RemarkSee IMPORTFILE for details on use of importStr()

3.6.5.36 contin

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

3.6.5.37 stepped

FunctionReturns stepped reverse-acting control value, e.g. for lighting control
Syntaxfloat stepped( int nsteps, float sp, float val)
Remarkstepped 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

valresult
val \(<\) 41
4 \(\leq\) val \(<\) 8.667
8 \(\leq\) val \(<\) 12.333
val \(\geq\) 120

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.

  1. 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;
  1. 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

objNameis 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.
memberis 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.

subhourlychanges in each “subhour” used in simulation. Subhours are commonly 15-minute intervals for models using znModel=CNE or 2-minute intervals for CSE znModels.
hourlychanges 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.
dailychanges at each simulated midnite.
monthlychanges 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 timevalue 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 timevalue 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.
constantdoes 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:

These types discussed in the section on expression types.

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

UnitsLegal RangeDefaultRequiredVariability
ft2x > 0wnHeight * wnWidthNoconstant

where the column headers have the following meaning:

Unitsunits of measure (lb., ft, Btu, etc.) where applicable
Legallimits of valid range for numeric inputs; valid choices
Rangefor choice members, etc.
Defaultvalue assumed if member not given; applicable only if not required
RequiredYES if you must give this member
Variabilityhow 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.

UnitsLegal RangeDefaultRequiredVariability
NO, YESYESNoconstant

begDay=date

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

UnitsLegal RangeDefaultRequiredVariability
dateJan 1Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
dateDec 31Noconstant

jan1DoW=choice

Day of week on which January 1 falls.

UnitsLegal RangeDefaultRequiredVariability
SUN, MON,
TUE, WED,
THU, FRI,
SAT
THUNoconstant

workDayMask=int TODO

UnitsLegal RangeDefaultRequiredVariability
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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 07Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 04Noconstant

nSubhrTicks=int

Number of subhour ticks used per nSubSteps for DHWSYS simulation.

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

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 060/nSubStepsNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.001Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 00.0001Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.0001Noconstant

ebTolDay=float

Daily energy balance error tolerance.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.0001Noconstant

ebTolHour=float

Hourly energy balance error tolerance.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.0001Noconstant

ebTolSubhr=float

Sub-hourly energy balance error tolerance.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.0001Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\geq\) 01 oFNoconstant

unMetTzTolWarnHrs=float

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

UnitsLegal RangeDefaultRequiredVariability
hrx \(\geq\) 0150Noconstant

grndMinDim=float

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

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 00.066Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 1.01.5Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
HOURLY, SUBHOURLYHOURLYNoconstant

humMeth=choice

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

ROBRob’s backward difference method. Works well within limitations of backward difference approach.
PHILPhil’s central difference method. Should be better if perfectedcoma but initialization at air handler startup is unresolved*coma and ringing has been observed.
UnitsLegal RangeDefaultRequiredVariability
ROB, PHILROBNoconstant

dflExH=float

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

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 02.64Noconstant

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 0o \(\leq\) x \(<\) 360o is given, it is normalized to that range.

UnitsLegal RangeDefaultRequiredVariability
o (degrees)unrestricted0Noconstant

elevation=float

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

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00 (sea level)Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
63 charactersblank (no titleNoconstant

runSerial=int

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

UnitsLegal RangeDefaultRequiredVariability
0 \(leq\) x \(leq\) 9990Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
YES, NOYESNoconstant

DTbegDay=date

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

UnitsLegal RangeDefaultRequiredVariability
datesecond Sunday in MarchNoconstant

DTendDay=date

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

UnitsLegal RangeDefaultRequiredVariability
datefirst Sunday in NovemberNoconstant

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.

ChoiceVentilation Strategy Available
NONENone
WHOLEBUILDINGIZXFER (window and whole-house fan)
RSYSOAVRSYS 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
UnitsLegal RangeDefaultRequiredVariability
Choices aboveWHOLEBUILDINGNohourly

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.

ChoiceEffect
PENUMBRACalculate shading using the Penumbra model
NONEDisable advanced shading calculations
UnitsLegal RangeDefaultRequiredVariability
Choices abovePENUMBRANoconstant

slrInterpMeth=choice

Solar interpolation method.

Choice
CSE
TRNSYS
UnitsLegal RangeDefaultRequiredVariability
See table aboveCSENoconstant

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).

UnitsLegal RangeDefaultRequiredVariability
lbm/secx \(>\) 00.00125 (about 1 cfm)Noconstant

ANTolRel=float

AirNet relative convergence tolerance. See AnTolAbs just above.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.0001Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
lb/ft2x \(\gt\) 010Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
lb/ft2x \(\gt\) 030Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
oFx \(>\) 01Noconstant

AWTrigSlr=float

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

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.05Noconstant

AWTrigH=float

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

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.1Noconstant

4.1.4 TOP Weather Data Items

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

$radBeambeam irradiance on tracking surface (integral for hour, Btu/ft2).
$radDiffdiffuse irradiance on a horizontal surface (integral for hour, Btu/ft2).
$tDbOdry bulb temp (oF).
$tWbOwet bulb temp (oF).
$wOhumidity ratio
$windDirDegwind direction (degrees, NOT RADIANS; 0=N, 90=E).
$windSpeedwind 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.

UnitsLegal RangeDefaultRequiredVariability
file name,path optionalnoneYesconstant

skyModel=choice

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

ISOTROPICtraditional isotropic sky model
ANISOTROPICHay anisotropic model
UnitsLegal RangeDefaultRequiredVariability
choices aboveANISOTROPICNoconstant

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.

ChoiceDescription
DEFAULTDefault: tSky from weather file if available else Berdahl-Martin
BERDAHLMARTINBerdahl-Martin (tSky depends on dew point, cloud cover, and hour)
DRYBULBtSky = dry-bulb temperature (for testing)
BLASTBlast model (tSky depends on dry-bulb)
UnitsLegal RangeDefaultRequiredVariability
choices aboveDEFAULTNoconstant

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).

UnitsLegal RangeDefaultRequiredVariability
oFx \(\ge\) 060oNoconstant

refRH=float

Reference relative humidity (see above).

UnitsLegal RangeDefaultRequiredVariability
0 \(\leq\) x \(\leq\) 10.6Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\leq\) x \(\leq\) 10.2NoMonthly-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.

UnitsLegal RangeDefaultRequiredVariability
0.0 \(le\) x \(le\) 1.00.8Noconstant

grndRf

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

UnitsLegal RangeDefaultRequiredVariability
ftx \(\geq\) 0.00.1Noconstant

windSpeedMin=float

Minimum value for wind speed

UnitsLegal RangeDefaultRequiredVariability
mphx \(\ge\) 00.5Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 00.25Noconstant

terrainClass=int

Specifies characteristics of ground terrain in the project region.

1ocean or other body of water with at least 5 km unrestricted expanse
2flat terrain with some isolated obstacles (buildings or trees well separated)
3rural areas with low buildings, trees, etc.
4urban, industrial, or forest areas
5center of large city
UnitsLegal RangeDefaultRequiredVariability
1 \(\leq\) x \(\leq\) 54Noconstant

radBeamF=float

Multiplier for direct normal (beam) irradiance

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Noconstant

radDiffF=float

Multiplier for diffuse horizonal irradiance.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Noconstant

hConvMod=choice

Enable/disable convection convective coefficient pressure modification factor.

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

UnitsLegal RangeDefaultRequiredVariability
YES, NOYESNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
ft2/hrx \(>\) 00.025Noconstant

soilCond=float

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

UnitsLegal RangeDefaultRequired**Variability
Btuh-ft/ft2-oFx \(>\) 01.0Noconstant

soilSpHt=float

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

UnitsLegal RangeDefaultRequiredVariability
Btu/lb-oFx \(>\) 00.1Noconstant

soilDens=float

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

UnitsLegal RangeDefaultRequiredVariability
lb/ft3x \(>\) 0115Noconstant

farFieldWidth=float

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

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 0130Noconstant

deepGrndCnd=choice

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

UnitsLegal RangeDefaultRequiredVariability
WATERTABLE, ZEROFLUXZEROFLUXNoconstant

deepGrndDepth=float

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

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 0130Noconstant

deepGrndT=float

Deep-ground temperature. Used when deepGrndCnd=WATERTABLE.

UnitsLegal RangeDefaultRequiredVariability
Fx \(>\) 0Annual average drybulb temperatureNohourly

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
1TDV Data (TDV/Btu), runNumber, runNumber is not checked
2timestamp optionally in quotes accessible via @TOP.TDVFileTimeStamp
3title, hour title (in quotes if it contains commas) accessible via @TOP.TDVFileTitle
4tdvElec, 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.

ProbeVariabilityDescription
@Weather.tdvElecHourcurrent hour electricity TDV
@Weather.tdvFuelHourcurrent hour fuel TDV
@Weather.tdvElecPkDaycurrent day peak electricity TDV (includes future hours). Updated at hour 23 during daylight savings.
@Weather.tdvElecAvgDaycurrent day average electricity TDV (includes future hours)
@Weather.tdvElecPvPkDayprevious day peak electricity TDV
@Weather.tdvElecAvg01Dayprevious day average electricity TDV
@weather.tdvElecHrRankDayhour 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.tdvFileTimeStampConstantTDV file timestamp (line 2 of header)
@weatherFile.tdvFileTitleConstantTDV file title (line 3 of header)
@Top.tdvFNameConstantTDV 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.

UnitsLegal RangeDefaultRequiredVariability
file name, path optional(no TDV file)Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
linesx \(\ge\) 5066Noconstant

repTopM=int

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

UnitsLegal RangeDefaultRequiredVariability
lines0 \(\geq\) x \(\geq\) 123Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
lines0 \(\geq\) x \(\geq\) 123Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
characters78 \(\leq\) x \(\leq\) 13278Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

4.1.7 TOP Autosizing

doAutoSize=choice

Controls invocation of autosizing phase prior to simulation.

UnitsLegal RangeDefaultRequiredVariability
YES, NONO, unless AUTOSIZE commands in inputNoconstant

auszTol=float

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

UnitsLegal RangeDefaultRequiredVariability
.005Noconstant

heatDsTDbO=float

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

UnitsLegal RangeDefaultRequiredVariability
oFnoneNohourly

heatDsTWbO=float

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

UnitsLegal RangeDefaultRequiredVariability
oFx \(\ge\) 0derived assuming RH=.7Nohourly

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.

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.

UnitsLegal RangeDefaultRequiredVariability
name of DESCONDnoneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
datesnoneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
monthsnoneNoconstant

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

UnitsLegal RangeDefaultRequiredVariability
0 - 51Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
0Noconstant

dbgPrintMask=int

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

UnitsLegal RangeDefaultRequiredVariability
0Nohourly

dbgFlag=int

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

UnitsLegal RangeDefaultRequiredVariability
0Nosubhourly

doCoverage=choice

Enables expression code coverage reporting. Development aid.

UnitsLegal RangeDefaultRequiredVariability
NO, YESNONoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneYesconstant

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.

UnitsLegal RangeDefaultRequiredVariability
dateblankNoconstant

hdDateObs=date

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

UnitsLegal RangeDefaultRequiredVariability
datehdDateTrueNoconstant

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).

UnitsLegal RangeDefaultRequiredVariability
YES/NOYESNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
FIRST SECOND THIRD FOURTH LASTFIRSTNoconstant

hdMon=choice

Month that the holiday is observed.

UnitsLegal RangeDefaultRequiredVariability
JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DECnonerequired if hdCase givenconstant

hdDow=choice

Day of the week that the holiday is observed.

UnitsLegal RangeDefaultRequiredVariability
SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAYMONDAYrequired if hdCase givenconstant

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.

UnitsLegal RangeDefaultRequiredVariability
noneconstant

Examples of valid HOLIDAY object specifications:

    HOLIDAY MAYDAY;
        hdDateTrue = May 1;
    HOLIDAY MAYDAY;
        hdDateTrue = May 1;
        hdDateObs  = May 3;
    HOLIDAY MAYDAY;
        hdDateTrue = May 1;
        hdOnMonday = No;
    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 Day3rd Monday in February
Memorial Daylast Monday in May
Fourth of July*July 4
Labor Day1st Monday in September
Columbus Day2nd Monday in October
Veterans Day*November 11
Thanksgiving4th 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:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneYesconstant

dcDay=date

Calendar date for this design cooling condition.

UnitsLegal RangeDefaultRequiredVariability
1-365200Noconstant

dcDB=float

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

UnitsLegal RangeDefaultRequiredVariability
oFno-limitations?0.0Noconstant

dcMCDBR=float

Coincident daily dry-bulb range.

UnitsLegal RangeDefaultRequiredVariability
oFno-limitations?noneNoconstant

dcMCWB=float

Coincident wet-bulb design temperature.

UnitsLegal RangeDefaultRequiredVariability
oFno-limitations?noneNoconstant

dcMCWBR=float

Coincident daily wet-bulb range.

UnitsLegal RangeDefaultRequiredVariability
oFno-limitations?noneNoconstant

dcWindSpeed=float

Wind speed for design conditions.

UnitsLegal RangeDefaultRequiredVariability
mphx \(\geq\) 00.0Noconstant

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.

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.

UnitsLegal RangeDefaultRequiredVariability
0 irradianceNoconstant

dcEbnSlrNoon=float
dcEdhSlrNoon=float

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

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2x \(\geq\) 00 irradianceNoconstant

endDesCond

Optionally indicates the end of the descond definition.

UnitsLegal RangeDefaultRequiredVariability
noneNo

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”.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneYesconstant

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).

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 0noneNoconstant

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.

UnitsLegal RangeDefaultRequired**Variability
Btuh-ft/ft2-oFx \(>\) 0noneYesconstant

matCondT=float

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

UnitsLegal RangeDefaultRequiredVariability
oFx \(>\) 070 oFNoconstant

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*(Tlayer – matCondT))

UnitsLegal RangeDefaultRequiredVariability
oF-10Noconstant

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

matSpHt=float

Specific heat of material.

UnitsLegal RangeDefaultRequiredVariability
Btu/lb-oFx \(\ge\) 00 (thermally massless)Noconstant

matDens=float

Density of material.

UnitsLegal RangeDefaultRequiredVariability
lb/ft3x \(\ge\) 00 (massless)Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
ft2-oF/Btuhx \(>\) 0noneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneYesconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 0calculated from LAYERsif omitted, LAYERs must followconstant

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.

UnitsLegal RangeDefaultRequiredVariability
N/ANoconstant

Related Probes:

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.

Two-dimensional context
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:

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

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.

Foundation wall dimensions
Foundation wall dimensions

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneYesconstant

fdWlHtAbvGrd=float

Wall height above grade.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\geq\) 00.0Noconstant

fdWlDpBlwSlb=float

Wall depth below slab.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\geq\) 00.0Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
Name of a Constructionnoneif a slab foundationconstant

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

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.

Foundation block references
Foundation block references

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).

Foundation block example
Foundation block example

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.

UnitsLegal RangeDefaultRequiredVariability
Name of a MaterialnoneYesconstant

fbX1Ref=choice

Relative X origin for fbX1 point. Options are:

UnitsLegal RangeDefaultRequiredVariability
choices aboveWALLINTNoconstant

fbZ1Ref=choice

Relative Z origin for fbZ1 point. Options are:

UnitsLegal RangeDefaultRequiredVariability
choices aboveWALLTOPNoconstant

fbX1=float

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

UnitsLegal RangeDefaultRequiredVariability
ft0.0Noconstant

fbZ1=float

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

UnitsLegal RangeDefaultRequiredVariability
ft0.0Noconstant

fbX2Ref=choice

Relative X origin for fbX2 point. Options are:

UnitsLegal RangeDefaultRequiredVariability
choices aboveWALLINTNoconstant

fbZ2Ref=choice

Relative Z origin for fbZ2 point. Options are:

UnitsLegal RangeDefaultRequiredVariability
choices aboveWALLTOPNoconstant

fbX2=float

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

UnitsLegal RangeDefaultRequiredVariability
ft0.0Noconstant

fbZ2=float

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

UnitsLegal RangeDefaultRequiredVariability
ft0.0Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

lrMat=matName

Name of primary MATERIAL in layer.

UnitsLegal RangeDefaultRequiredVariability
name of a MATERIALnoneYesconstant

lrThk=float

Thickness of layer.

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 0Required if matThk not specified in referenced lrMatNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a MATERIALno framed layerNoconstant

lrFrmFrac=float

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

UnitsLegal RangeDefaultRequiredVariability
0 \(\leq\) x \(\leq\) 1no framed layerRequired if lrFrmMat specified, else disallowedconstant

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:

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 fromWINDOW objects, below.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneYesconstant

gtModel=choice

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

UnitsLegal RangeDefaultRequiredVariability
SHGC, ASHWATSHGCNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 0noneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 0noneNoconstant

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

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 1noneYesconstant

gtSMSO=float

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

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 11.0NoMonthly - Hourly

gtSMSC=float

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

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 1gtSMSO (no shades)NoMonthly - 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.

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 1gtSHGCONoMonthly - 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)

UnitsLegal RangeDefaultRequiredVariability
floatanynoneYesconstant

gtDMSHGC=float

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

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 1noneYesconstant

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.

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 1noneYesconstant

gtNGlz=int

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

UnitsLegal RangeDefaultRequiredVariability
0 \(<\) x \(\leq\) 42Noconstant

gtExShd=choice

Exterior shading type (ASHWAT only).

UnitsLegal RangeDefaultRequiredVariability
NONE INSCRNNONENoconstant

gtInShd=choice

Interior shade type (ASHWAT only).

UnitsLegal RangeDefaultRequiredVariability
NONE DRAPEMEDNONENoconstant

gtDirtLoss=float

Glazing dirt loss factor.

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 10Noconstant

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

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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”).

ClgCooling
HtgHeating (includes heat pump compressor)
HPBUHeat pump resistance heating (backup and defrost)
DHWDomestic (service) hot water
DHWBUDomestic (service) hot water heating backup (HPWH resistance)
DHWMFLDomestic (service) hot water heating multi-family loop pumping and loss makeup
FANCFans, AC and cooling ventilation
FANHFans, heating
FANVFans, IAQ venting
FANFans, other purposes
AUXHVAC auxiliaries such as pumps
PROCProcess
LITLighting
RCPReceptacles
EXTExterior lighting
REFRRefrigeration
DISHDishwashing
DRYClothes drying
WASHClothes washing
COOKCooking
USER1User-defined category 1
USER2User-defined category 2
BTBattery charge power
PVPhotovoltaic 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:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneYesconstant

mtrDemandRate=float

DmdCost per Btu of demand, for a month.

UnitsLegal RangeDefaultRequiredVariability
N/ANoconstant

mtrRate=float

Cost of energy use per Btu.

UnitsLegal RangeDefaultRequiredVariability
N/ANoconstant

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 –

UnitsLegal RangeDefaultRequiredVariability
names of METERsNoconstant

mtrSubmeterMults=list of up to 50 floats

Submeter multipliers. Use cases for multipliers include –

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.

UnitsLegal RangeDefaultRequiredVariability
1Nohourly

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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.

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneYesconstant

endDhwMeter

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneYesconstant

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneYesconstant

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 –

UnitsLegal RangeDefaultRequiredVariability
names of LOADMETERsNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
1Nosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneYesconstant

znModel=choice

Selects model for zone.

CNEOlder central difference model based on original CALPAS methods. Not fully supported and not suitable for current compliance applications.
CZMConditioned zone model. Forward-difference, short time step methods are used.
UZMUnconditioned zone model. Identical to CZM except heating and cooling are not supported. Typically used for attics, garages, and other ancillary spaces.
UnitsLegal RangeDefaultRequiredVariability
choices aboveCNENoconstant

znArea=float

Nominal zone floor area.

UnitsLegal RangeDefaultRequiredVariability
ft2x \(>\) 0noneYesconstant

znVol=float

Nominal zone volume.

UnitsLegal RangeDefaultRequiredVariability
ft3x \(>\) 0noneYesconstant

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 0o to 360o are normalized to that range.

UnitsLegal RangeDefaultRequiredVariability
degreesunrestricted0Noconstant

znFloorZ=float

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

UnitsLegal RangeDefaultRequiredVariability
ftunrestricted0Noconstant

znCeilingHt=float

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

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 0znVol / znAreaNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 0znFloorZ + infStories8*Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
Btu/oFx \(\geq\) 03.5 znArea*Noconstant

znHcAirX=float

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

UnitsLegal RangeDefaultRequiredVariability
ACHx \(>\) 0as modeledNosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oF.2.2Nohourly

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\leq\) x \(\leq\) 11 when cooling was used in previous hour, else 0Nohourly

znTH=float

Heating set point for znModel=CZM.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\geq\) 0noneNosubhourly

znTD=float

Desired set point (temperature maintained with ventilation if possible) for znModel=CZM

UnitsLegal RangeDefaultRequiredVariability
oFx \(\geq\) 0noneNosubhourly

znTC=float

Cooling set point for znModel=CZM.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\geq\) 0noneNosubhourly

CZM zone heating and cooling is provided either via an RSYS HVAC system or by “magic” heat transfers specified by znQxxx items.

znRSys=rsysName

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

UnitsLegal RangeDefaultRequiredVariability
RSYS name(no RSYS)Noconstant

znQMxH=float

Heating capacity at current conditions

UnitsLegal RangeDefaultRequiredVariability
Btuhx \(\geq\) 0noneNohourly

znQMxHRated=float

Rated heating capacity

UnitsLegal RangeDefaultRequiredVariability
Btuhx \(\geq\) 0noneNoconstant

znQMxC=float

Cooling capacity at current conditions

UnitsLegal RangeDefaultRequiredVariability
Btuhx \(\leq\) 0noneNohourly

znQMxCRated=float

Rated cooling capacity

UnitsLegal RangeDefaultRequiredVariability
Btuhx \(\leq\) 0noneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
1/hrx \(\geq\) 00.5Nohourly

infELA=float

Zone effective leakage area (ELA).

UnitsLegal RangeDefaultRequiredVariability
in2x \(\geq\) 00.0Nohourly

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 –

1no obstructions or local shielding
2light local shielding with few obstructions
3moderate local shielding, some obstructions within two house heights
4heavy shielding, obstructions around most of the perimeter
5very heavy shielding, large obstructions surrounding the perimeter within two house heights
UnitsLegal RangeDefaultRequiredVariability
1 \(\leq\) x \(\leq\) 53Noconstant

infStories=int

Number of stories in zone, used in ELA model.

UnitsLegal RangeDefaultRequiredVariability
1 \(\leq\) x \(\leq\) 31Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 0derived from znEaveZ and infShldNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of an AFMETERnot recordedNoconstant

znLoadMtr=ldMtrName

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

UnitsLegal RangeDefaultRequiredVariability
name of a LOADMETERnot recordedNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 11Nohourly

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.

UnitsLegal RangeDefaultRequiredVariability
cfmx \(\geq\) 00, no fanIf fan presentconstant

xfanPress=float

Exhaust fan external static pressure.

UnitsLegal RangeDefaultRequiredVariability
inches0.05 \(\leq\) x \(\leq\) 1.00.3Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
W/cfmx \(>\) 0derived from xfanEffIf xfanEff and xfanShaftBhp not presentconstant

xfanEff=float

Exhaust fan/motor/drive combined efficiency.

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 10.08Noconstant

xfanShaftBhp=float

Fan shaft power at design flow and pressure.

UnitsLegal RangeDefaultRequiredVariability
BHPx \(>\) 0derived from xfanElecPwr and xfanVfDsIf xfanElecPwr not presentconstant

xfanMtr=mtrName

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

UnitsLegal RangeDefaultRequiredVariability
name of a METERnot recordedNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

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).

UnitsLegal RangeDefaultRequiredVariability
name of ZONEparent zone if anyNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btuhno restrictionsnoneYeshourly

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.

UnitsLegal RangeDefaultRequiredVariability
name of METERnoneNoconstant

gnEndUse=choice

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

ClgCooling
HtgHeating (includes heat pump compressor)
HPBUHeat pump resistance heating (backup and defrost)
DHWDomestic (service) hot water
DHWBUDomestic (service) hot water heating backup (HPWH resistance)
DHWMFLDomestic (service) hot water heating multi-family loop pumping and loss makeup
FANCFans, AC and cooling ventilation
FANHFans, heating
FANVFans, IAQ venting
FANFans, other purposes
AUXHVAC auxiliaries such as pumps
PROCProcess
LITLighting
RCPReceptacles
EXTExterior lighting
REFRRefrigeration
DISHDishwashing
DRYClothes drying
WASHClothes washing
COOKCooking
USER1User-defined category 1
USER2User-defined category 2
BTBattery charge power
PVPhotovoltaic power generation
UnitsLegal RangeDefaultRequiredVariability
Codes listed abovenoneRequired if gnMeter is givenconstant

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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\leq\) x \(\leq\) 11.Nohourly

gnFrPl=float

Fraction of gain going to plenum.

UnitsLegal RangeDefaultRequiredVariability
gnFrZn + gnFrPl + gnFrRtn \(\leq\) 10.Nohourly

gnFrRtn=float

Fraction of gain going to return.

UnitsLegal RangeDefaultRequiredVariability
gnFrZn + gnFrPl + gnFrRtn \(\leq\) 10.Nohourly

gnFrRad=float

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

UnitsLegal RangeDefaultRequiredVariability
0 \(\leq\) x \(\leq\) 10.0Nohourly

gnFrLat=float

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

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.0Nohourly

gnDlFrPow=float

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

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 11.0Nohourly

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.

UnitsLegal RangeDefaultRequiredVariability
name of a DHWSYSno DHWSYS/GAIN linkageNoconstant

gnCtrlDHWMETER=dhwMtrName

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

UnitsLegal RangeDefaultRequiredVariability
name of DHWMETER0Noconstant

gnCtrlDHWEndUse=dhwEndUseName

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

UnitsLegal RangeDefaultRequiredVariability
DHW end useTotalNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

sfType=choice

Type of surface:

FLOORSurface 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.
WALLSurface defines a ‘side’ of the zone; its outside is not adjacent to the current zone.
CEILINGSurface 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.

UnitsLegal RangeDefaultRequiredVariability
FLOOR WALL CEILINGnoneYesconstant

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.).

UnitsLegal RangeDefaultRequiredVariability
ft2x \(>\) 0noneYesconstant

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 = FLOORsfTilt=180, default = 180 (fixed value)
sfType = WALL60 \(<\) sfTilt \(<\) 180, default = 90
sfType = CEILING0 \(\leq\) sfTilt \(\leq\) 60, default = 0
UnitsLegal RangeDefaultRequiredVariability
degreesDependent upon sfType See aboveDependent upon sfType See aboveNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
degreesunrestrictednoneRequired if sfTilt \(\neq\) 0 and sfTilt \(\neq\) 180constant

sfModel=choice

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

QUICKSurface is modeled using a simple conductance. Heat capacity effects are ignored. Either sfCon or sfU (next) can be specified.
DELAYED, DELAYED_HOUR, DELAYED_SUBHOURSurface 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.
AUTOProgram 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).
KIVAUses a two-dimensional finite difference model to simulate heat flow through foundation surfaces.
UnitsLegal RangeDefaultRequiredVariability
QUICK, DELAYED, DELAYED_HOUR, DELAYED_SUBOUR , AUTO, 2D_FNDAUTONoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 0Determined from sfConif sfCon not givenconstant

sfCon=conName

Name of CONSTRUCTION of the surface.

UnitsLegal RangeDefaultRequiredVariability
Name of a CONSTRUCTIONnoneunless sfU givenconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 00.5Noconstant

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.

AMBIENTExterior surface is exposed to the ‘weather’ as read from the weather file. Solar gain is calculated using solar geometry, sfAzm, sfTilt, and sfExAbs.
SPECIFIEDTExterior 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.
ADJZNExterior 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.
GROUNDThe 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.
ADIABATICExterior surface heat flow is 0. Thermal storage effects of delayed surfaces are modeled.

sfExAbs=float

Surface exterior absorptivity.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.5Required if sfExCnd = AMBIENT or sfExCnd = SPECIFIEDTmonthly-hourly

sfInAbs=float

Surface interior solar absorptivity.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(le\) 1sfType = CEILING, 0.2; sfType = WALL, 0.6; sfType = FLOOR, 0.8Nomonthly-hourly

sfExEpsLW=float

Surface exterior long wave (thermal) emittance.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.9Noconstant

sfInEpsLW=float

Surface interior long wave (thermal) emittance.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.9Noconstant

sfExT=float

Exterior air temperature.

UnitsLegal RangeDefaultRequiredVariability
oFunrestrictednoneRequired if sfExCnd = SPECIFIEDThourly

sfAdjZn=znName

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

UnitsLegal RangeDefaultRequiredVariability
name of a ZONEnoneRequired when
sfExCnd = ADJZN
constant

sfGrndRefl=float

Ground reflectivity for this surface.

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 1grndReflNoMonthly - Hourly

sfInH=float

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

sfType = FLOOR or CEILING1.32
other1.5
UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 0See aboveNoconstant

sfExH=float

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

sfExCnd = AMBIENTdflExH (Top-level member, described above)
sfExCnd = SPECIFIEDTdflExH (described above)
sfExCnd = ADJZN1.5
sfExCnd = ADIABATICnot applicable
UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 0see aboveNoconstant

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.

ModelExposed to ambientExposed to zone
UNIFIEDdefault CSE modeldefault CSE model
INPUThc = sfExHcMulthc = sfxxHcMult
AKBARIAkbari modeln/a
WALTONWalton modeln/a
WINKELMANNWinkelmann modeln/a
DOE2DOE2 modeln/a
MILLSn/aMills model
ASHRAEn/aASHRAE handbook values
TARPn/aTARP model

sfExHcModel=choice

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

UnitsLegal RangeDefaultRequiredVariability
choices aboveUNIFIEDNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 010Noconstant

sfExHcMult=float

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

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Nosubhourly

sfExRf=float

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

Roughness IndexsfExRfExample
1 (very rough)2.17Stucco
2 (rough)1.67Brick
3 (medium rough)1.52Concrete
4 (Medium smooth)1.13Clear pine
5 (Smooth)1.11Smooth plaster
6 (Very Smooth)1Glass
UnitsLegal RangeDefaultRequiredVariability
sfExHcModel = WINKELMANN: 1.66 else 2.17Noconstant

sfInHcModel=choice

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

UnitsLegal RangeDefaultRequiredVariability
choices above (see sfExHcModel)UNIFIEDNoconstant

sfInHcMult=float

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

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Nosubhourly

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.

UnitsLegal RangeDefaultRequired**Variability
Name of a Foundationnonewhen
sfExCnd = GROUND and
sfType = Floor
constant

sfFndFloor=sfName

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

UnitsLegal RangeDefaultRequiredVariability
Name of a Surfacenonewhen
sfExCnd = GROUND and
sfType = Wall
constant

sfHeight=float

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

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 0nonewhen sfType is WALL and sfExtCnd is GROUNDconstant

sfExpPerim=float

Exposed perimeter of foundation floors.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\geq\) 0nonewhen sfType is FLOOR, sfFnd is set, and sfExtCnd is GROUNDconstant

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.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 0noneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(\ge\) 0see aboveNoconstant

sfExRConGrnd=float

Resistance overall construction resistance. TODO: full documentation.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 0noneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

wnHeight=float

Overall height of window (including frame).

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 0noneYesconstant

wnWidth=float

Overall width of window (including frame).

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 0noneYesconstant

wnArea=float

Overall area of window (including frame).

UnitsLegal RangeDefaultRequiredVariability
ft2x \(>\) 0wnHeight wnWidth*Noconstant

wnMult=float

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

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

wnModel=choice

Selects window model

UnitsLegal RangeDefaultRequiredVariability
SHGC, ASHWATSHGCNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 0noneYesconstant

wnUNFRC=float

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

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 0gtUNFRCRequired when wnModel = ASHWATconstant

wnExEpsLW=float

Window exterior long wave (thermal) emittance.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.84Noconstant

wnInEpsLW=float

Window interior long wave (thermal) emittance.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.84Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 010000Noconstant

wnExH=float

Window exterior surface (air film) conductance.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 0same as owning surfaceNoconstant

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.

ModelExposed to ambientExposed to zone
UNIFIEDdefault CSE modeldefault CSE model
INPUThc = wnExHcMulthc = wnxxHcMult
AKBARIAkbari modeln/a
WALTONWalton modeln/a
WINKELMANNWinkelmann modeln/a
MILLSn/aMills model
ASHRAEn/aASHRAE handbook values

wnExHcModel=choice

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

UnitsLegal RangeDefaultRequiredVariability
choices aboveUNIFIEDNoconstant

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).

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 010Noconstant

wnExHcMult=float

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

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Nosubhourly

wnInHcModel=choice

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

UnitsLegal RangeDefaultRequiredVariability
choices above (see wnExHcModel)UNIFIEDNoconstant

wnInHcMult=float

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

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Nosubhourly

wnSHGC=float

Rated Solar Heat Gain Coefficient (SHGC) for the window assembly.

UnitsLegal RangeDefaultRequiredVariability
fraction0 < x < 1gtSHGCNoconstant

wnFMult=float

Frame area multiplier = areaGlaze / areaAssembly

UnitsLegal RangeDefaultRequiredVariability
fraction0 < x < 1gtFMult or 1Noconstant

wnSMSO=float

SHGC multiplier with shades open. Overrides gtSMSO.

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 1gtSMSO or 1NoMonthly - Hourly

wnSMSC=float

SHGC multiplier with shades closed. Overrides gtSMSC

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(leq\) x \(leq\) 1wnSMSO or gtSMSCNoMonthly - Hourly

wnNGlz=int

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

UnitsLegal RangeDefaultRequiredVariability
0 \(<\) x \(leq\) 4gtNGLZRequired when wnModel = ASHWATconstant

wnExShd=choice

Exterior shading type (ASHWAT only).

UnitsLegal RangeDefaultRequiredVariability
NONE, INSCRNgtExShdNoconstant

wnInShd=choice

Interior shade type (ASHWAT only).

UnitsLegal RangeDefaultRequiredVariability
NONE, DRAPEMEDgtInShdNoconstant

wnDirtLoss=float

Glazing dirt loss factor.

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 1noneNoconstant

wnGrndRefl=float

Ground reflectivity for this window.

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 1sfGrndReflNoMonthly - 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

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 10.5 - 0.5 cos(tilt) = .5 for vertical surfaceNoMonthly - 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.

UnitsLegal RangeDefaultRequiredVariability
fraction0 \(\leq\) x \(\leq\) 10.5 + 0.5 .5 for vertical surfaceNoMonthly - 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).

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

ohDepth=float

Depth of overhang (from plane of window to outside edge of overhang). A zero value indicates no overhang.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Nomonthly-hourly

ohDistUp=float

Distance from top of window to bottom of overhang.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Nomonthly-hourly

ohExL=float

Distance from left edge of window (as viewed from the outside) to the left end of the overhang.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Nomonthly-hourly

ohExR=float

Distance from right edge of window (as viewed from the outside) to the right end of the overhang.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Nomonthly-hourly

ohFlap=float

Height of flap hanging down from outer edge of overhang.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Nomonthly-hourly

lfDepth=float

Depth of left fin from plane of window. A zero value indicates no fin.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Nomonthly-hourly

lfTopUp=float

Vertical distance from top of window to top of left fin.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Nomonthly-hourly

lfDistL=float

Distance from left edge of window to left fin.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Nomonthly-hourly

lfBotUp=float

Vertical distance from bottom of window to bottom of left fin.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Nomonthly-hourly

rfDepth=float

Depth of right fin from plane of window. A 0 value indicates no fin.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Nomonthly-hourly

rfTopUp=float

Vertical distance from top of window to top of right fin.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Nomonthly-hourly

rfDistR=float

Distance from right edge of window to right fin.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Nomonthly-hourly

rfBotUp=float

Vertical distance from bottom of window to bottom of right fin.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Nomonthly-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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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).

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a SURFACEnoneYesconstant

sgSide=choice

Designates the side of the surface to which the gain is to be targeted:

INTERIORApply gain to interior of surface
EXTERIORApply gain to exterior of surface
UnitsLegal RangeDefaultRequiredVariability
INTERIOR, EXTERIORSide of surface in zone containing window; or INTERIOR if both sides are in zone containing window.Yesconstant

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).

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1,and sum of window’s sgFSO’s \(\le\) 1noneYesmonthly-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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1, and sum of window’s sgFSC’s \(\le\) 1sgFSONomonthly-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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

drArea=float

Overall area of door.

UnitsLegal RangeDefaultRequiredVariability
ft2x \(>\) 0noneYesconstant

drModel=choice

Provides user control over how CSE models conduction for this door:

QUICKSurface is modeled using a simple conductance. Heat capacity effects are ignored. Either drCon or drU (next) can be specified.
DELAYED, DELAYED_HOUR, DELAYED_SUBOURSurface 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.
AUTOProgram selects Quick or appropriate Delayed automatically according to the time constant of the surface (if drU is specified, Quick is selected).
FD or FORWARD_DIFFERENCESelects the forward difference model (used with short time steps and the CZM/UZM zone models)
UnitsLegal RangeDefaultRequiredVariability
choices aboveAUTONoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 0Determined from drConif drCon not givenconstant

drCon=conName

Name of construction for door.

UnitsLegal RangeDefaultRequiredVariability
name of a CONSTRUCTIONnoneunless drU givenconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 00.5Noconstant

drExAbs=float

Door exterior solar absorptivity. Applicable only if sfExCnd of owning surface is AMBIENT or SPECIFIEDT.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 0same as owning surfaceNomonthly-hourly

drInAbs=float

Door interior solar absorptivity.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.5Nomonthly-hourly

drExEpsLW=float

Door exterior long wave (thermal) emittance.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.9Noconstant

drInEpsLW=float

Door interior long wave (thermal) emittance.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.9Noconstant

drInH=float

Door interior surface (air film) conductance. Ignored if drModel = Forward_Difference

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 0same as owning surfaceNoconstant

drExH=float

Door exterior surface (air film) conductance. Ignored if drModel = Forward_Difference

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 0same as owning surfaceNoconstant

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.

ModelExposed to ambientExposed to zone
UNIFIEDdefault CSE modeldefault CSE model
INPUThc = drExHcMulthc = drxxHcMult
AKBARIAkbari modeln/a
WALTONWalton modeln/a
WINKELMANNWinkelmann modeln/a
MILLSn/aMills model
ASHRAEn/aASHRAE handbook values

drExHcModel=choice

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

UnitsLegal RangeDefaultRequiredVariability
choices aboveUNIFIEDNoconstant

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).

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 010Noconstant

drExHcMult=float

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

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Nosubhourly

drExRf=float

Exterior roughness factor. Typical roughness values:

Roughness IndexdrExRfExample
1 (very rough)2.17Stucco
2 (rough)1.67Brick
3 (medium rough)1.52Concrete
4 (Medium smooth)1.13Clear pine
5 (Smooth)1.11Smooth plaster
6 (Very Smooth)1Glass
UnitsLegal RangeDefaultRequiredVariability
drExHcModel = WINKELMANN: 1.66 else 2.17Noconstant

drInHcModel=choice

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

UnitsLegal RangeDefaultRequiredVariability
choices above (see drExHcModel)UNIFIEDNoconstant

drInHcMult=float

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

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Nosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

prLen=float

Length of exposed perimeter.

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 0noneYesconstant

prF2=float

Perimeter conduction per unit length.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft-oFx \(>\) 0noneYesconstant

endPerimeter

Optionally indicates the end of the perimeter definition.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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.]

Insert Figure Title
Insert Figure Title

tuName

Optional name of terminal; follows the word “TERMINAL” if given.

UnitsLegal RangeDefaultRequiredVariability
63 charactersNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
oFx \(>\) 0no thermostat controlNohourly

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.

UnitsLegal RangeDefaultRequiredVariability
Btuhx \(\ge\) 00 if tuTLh given else no local heatFor set output local heathourly

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.

UnitsLegal RangeDefaultRequiredVariability
Btuhx \(\ge\) 0Yes, if tuTLh givenhourly

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0100Noconstant

tuLhNeedsFlow=choice

YESlocal 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)
NOno local heat or does not require air flow (e.g. baseboard heaters).
UnitsLegal RangeDefaultRequiredVariability
YES, NONONoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of an AIRHANDLERIf omitted, terminal has no air heating nor cooling capability.Noconstant

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.

UnitsLegal RangeDefaultRequired**Variability
oFx \(\ge\) 0No thermostat-controlled air heatingNohourly

tuTC=float

Air cooling thermostat set point; implies set temperatureair capability. May be scheduled as desired; to disable at certain times, schedule an extreme temperature such as 199.

UnitsLegal RangeDefaultRequired**Variability
oFx \(\ge\) 0No thermostat-controlled air coolingNohourly

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.

UnitsLegal RangeDefaultRequiredVariability
cfmx \(\ge\) 0largest of tuVfMn, tuVfMxH, and tuVfMxC if all are constantYes, if tuVfmn, tuVfmxH, or tuVfMxC is variablehourly

tuFxVfHC=float

Sizing factor for autosized terminal air flows. Default value (1.1) specifies 10% oversizing.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01.1Noconstant

tuVfMxHC=choice

Determines autosizing strategy for heating and cooling air flows.

SAMEtuVfMxH and tuVfMxC are set to the larger of the autosized values
DIFFERENTtuVfMxH and tuVfMxC are autosized independently
UnitsLegal RangeDefaultRequiredVariability
choices aboveDifferentNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
cfmAUTOSIZE or x \(\ge\) 0if tuTH or tuTC given, else no air heat/coolFor set output air operationhourly

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.

UnitsLegal RangeDefaultRequiredVariability
cfmAUTOSIZE or x \(\ge\) 0noneIf tuTH givenhourly

tuVfMxC=float

Maximum cooling air flow rate, before air handler limitations, used when the thermostat is calling for cooling continuously. tuVfMn overrides if larger.

UnitsLegal RangeDefaultRequiredVariability
cfmAUTOSIZE or x \(\ge\) 0noneIf tuTC givenhourly

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.05Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.1Noconstant

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:

ELECTRICElectric coil or heater, including separate heaters such as electric baseboards. 100% efficient; rated capacity always available.
HWHot water coil, using hot water from amHEATPLANT. Available capacity may be limited by HEATPLANT total capacity as well as by coil rated capacity.
UnitsLegal RangeDefaultRequiredVariability
ELECTRIC (future: HW)ELECTRIC, or NONE if no local heatNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btu/hrAUTOSIZE or x \(\gt\) 0noneYesconstant

tuhcFxCap=float

Capacity factor for autosized terminal heating coil. Default value (1.1) specifies 10% oversizing.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01.1Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a METERnot recordedNoconstant

tuhcHeatplant=heatplantName

Name of HEATPLANT for HW coil; disallowed for other coil types.

UnitsLegal RangeDefaultRequiredVariability
name of a HEATPLANTnoneIf tuhcType is HWconstant

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:

NONENo fan in this TERMINAL (default); input for other terminal fan members disallowed.
SERIESFan runs whenever scheduled ON (see tfanSched, next); if VAV cfm < terminal fan cfm (tfanVfDs), the additional flow comes from the return air.
PARALLELFan 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.
UnitsLegal RangeDefaultRequiredVariability
NONE, SERIES, PARALLELnoneYes, if fan presentconstant

tfanSched=choice

Terminal fan schedule. May be scheduled with an hourly variable expression.

OFFfan does not run
ONfan may run
HEATINGfan may run when local heat is in use
VAVfan 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.

UnitsLegal RangeDefaultRequiredVariability
OFF, ON, HEATING, VAVnoneYes (if fan present)hourly

tfanOffLeak=float

Backdraft leakage when terminal fan off., as a fraction of tfanVfDs.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.1 if fan presentNoconstant

tfanVfDs=float

Terminal fan design flow rate. To specify .x times zone or terminal cfm, use a CSE expression.

UnitsLegal RangeDefaultRequiredVariability
cfmx \(\le\) 0noneYes (if fan present)constant

tfanPress=float

Terminal fan external static pressure.

UnitsLegal RangeDefaultRequiredVariability
inches H2Ox \(\ge\) 00.3Noconstant

tfanEff=float

Terminal fan/motor/drive combined efficiency.

UnitsLegal RangeDefaultRequiredVariability
0 \(le\) x \(le\) 10.08Noconstant

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:

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.

UnitsLegal RangeDefaultRequiredVariability
0, 1, 0, 0, 0 (linear)Noconstant

tfanMtr=mtrName

Name of meter, if any, which is to record energy used by this terminal fan. The “fans” category is used.

UnitsLegal RangeDefaultRequiredVariability
name of a METERnot recordedNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 0noneNoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

izNVType=choice

Choice specifying the type of ventilation or leakage model to be used.

NONENo interzone ventilation
ONEWAYUncontrolled flow from izZn1 to izZn2 when izZn1 air temperature exceeds izZn2 air temperature (using ASHRAE high/low vent model).
TWOWAYUncontrolled flow in either direction (using ASHRAE high/low vent model).
AIRNETIZSingle opening to another zone (using pressure balance AirNet model). Flow is driven by buoyancy.
AIRNETEXTSingle opening to ambient (using pressure balance AirNet model). Flow is driven by buoyancy and wind pressure.
AIRNETHORIZHorizontal (large) opening between two zones, used to represent e.g. stairwells. Flow is driven by buoyancy; simultaneous up and down flow is modeled.
AIRNETEXTFANFan from exterior to zone (flow either direction).
AIRNETIZFANFan between two zones (flow either direction).
AIRNETEXTFLOWSpecified 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.
AIRNETIZFLOWSpecified 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.
AIRNETHERVHeat 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.
AIRNETDOASAir 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).

UnitsLegal RangeDefaultRequiredVariability
choices abovenoneNoconstant

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:

InfilExInfiltration from ambient
VentExNatural ventilation from ambient
FanExForced ventilation from ambient
InfilIzInterzone infiltration
VentIzInterzone natural ventilation
FanIzInterzone forced ventilation
DuctLkDuct leakage
HVACHVAC 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).

UnitsLegal RangeDefaultRequiredVariability
choices abovederived from IZXFER characteristicsNoconstant

izZn1=znName

Name of primary zone. Flow rates \(>\) 0 are into the primary zone.

UnitsLegal RangeDefaultRequiredVariability
name of a ZONEnoneYesconstant

izZn2=znName

Name of secondary zone.

UnitsLegal RangeDefaultRequiredVariability
name of a ZONEnonerequired unless constant izNVType = AIRNETEXT, AIRNETEXTFAN, AIRNETEXTFLOW, or AIRNETHERVconstant

izDOAS=oaName

Name of DOAS where air is supplied from (izVfMin > 0), or exhausting to (izVfMin < 0).

UnitsLegal RangeDefaultRequiredVariability
name of a DOASwhen izNVType = AIRNETDOASconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\gt\) 01Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btu/oFx \(\ge\) 00Nohourly

izALo=float

Area of low or only vent (typically VentOff)

UnitsLegal RangeDefaultRequiredVariability
ft2x \(\ge\) 00Nohourly

izAHi=float

Additional vent area (high vent or VentOn). If used in AIRNET, izAHi > izALo typically but this is not required.

UnitsLegal RangeDefaultRequiredVariability
ft2x \(\ge\) 0izALoNohourly

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.

UnitsLegal RangeDefaultRequiredVariability
oFOutdoor dry-bulbNosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
\(\gt\) 0Outdoor humidity ratioNosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
mph\(\ge\) 0Zone adjusted windspeedNosubhourly

izL1=float

Length or width of AIRNETHORIZ opening.

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 0noneif izNVType = AIRNETHORIZconstant

izL2=float

Width or length of AIRNETHORIZ opening.

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 0noneif izNVType = AIRNETHORIZconstant

izStairAngle=float

Stairway angle for AIRNETHORIZ opening. Use 90 for an open hole. Note that 0 prevents flow.

UnitsLegal RangeDefaultRequiredVariability
o degreesx \(>\) 034Noconstant

izHD=float

Vent center-to-center height difference (for TWOWAY) or vent height above nominal 0 level (for AirNet types)

UnitsLegal RangeDefaultRequiredVariability
ft0Noconstant

izNVEff=float

Vent discharge coefficient.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.8Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
cfmx \(\ge\) 00 (no fan)If fan presentconstant

izCpr=float

Wind pressure coefficient (for AIRNETEXT).

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 00Noconstant

izExp=float

Opening exponent (for AIRNETEXT).

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.5Noconstant

izVfMin=float

Minimum volume flow rate (VentOff mode).

UnitsLegal RangeDefaultRequiredVariability
cfmx \(\ge\) 0izfanVfDsNosubhourly

izVfMax=float

Maximum volume flow rate (VentOn mode)

UnitsLegal RangeDefaultRequiredVariability
cfmx \(\ge\) 0izVfMinNosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10Nosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10Nosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) izSRE0Nosubhourly

izEATR=float

Exhaust air transfer ratio for AIRNETHERV ventilator. NetFlow = (1 - EATR)*(grossFlow).

UnitsLegal RangeDefaultRequiredVariability
cfm0 \(\le\) x \(\le\) 10Nosubhourly

izLEF=float

Latent heat recovery effectiveness for AIRNETHERV ventilator. The default value (0) results in sensible-only heat recovery.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10Nosubhourly

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).

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10Nosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01 (balanced)Noconstant

izfanPress=float

Design or rated fan pressure.

UnitsLegal RangeDefaultRequiredVariability
inches H2Ox \(>\) 00.3Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
W/cfmx \(>\) 0derived from izfanEff and izfanShaftBhpIf izfanEff and izfanShaftBhp not presentconstant

izfanEff=float

Fan efficiency at design flow and pressure, as a fraction.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1derived from izfanShaftBhp if given, else 0.08Noconstant

izfanShaftBhp=float

Fan shaft brake horsepower at design flow and pressure.

UnitsLegal RangeDefaultRequiredVariability
bhpx \(>\) 0derived from izfanEff.Noconstant

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:

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 00, 1, 0, 0, 0 (linear)Noconstant

izFanMtr=mtrName

Name of meter, if any, to record energy used by supply fan. End use category used is specified by izFanEndUse (next).

UnitsLegal RangeDefaultRequiredVariability
name of a METERnot recordedNoconstant

izFanEndUse=choice

End use to which fan energy is recorded (in METER specified by izFanMtr). See METER for available end use choices.

UnitsLegal RangeDefaultRequiredVariability
end use choiceFanNoconstant

endIZXFER

Optionally indicates the end of the interzone transfer definition.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
cfmx \(\ge\) 0Sum of referencing IZXFER supply flowsNoconstant

oaSupFanPress=float

Design or rated fan pressure.

UnitsLegal RangeDefaultRequiredVariability
inches H2Ox \(>\) 00.3Noconstant

Only one of oaSupFanElecPwr, oaSupFanEff, and oaSupFanShaftBhp may be given.

oaSupFanElecPwr=float

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

UnitsLegal RangeDefaultRequiredVariability
W/cfmx \(>\) 0derived from oaSupFanEff and oaSupFanShaftBhpIf oaSupFanEff and oaSupFanShaftBhp not presentconstant

oaSupFanEff=float

Fan efficiency at design flow and pressure, as a fraction.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1derived from oaSupFanShaftBhp if given, else 0.08Noconstant

oaSupFanShaftBhp=float

Fan shaft brake horsepower at design flow and pressure.

UnitsLegal RangeDefaultRequiredVariability
bhpx \(>\) 0derived from oaSupFanEff.Noconstant

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:

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 00, 1, 0, 0, 0 (linear)Noconstant

oaSupFanMtr=mtrName

Name of meter, if any, to record energy used by supply fan. End use category used is specified by oaSupFanEndUse (next).

UnitsLegal RangeDefaultRequiredVariability
name of a METERnot recordedNoconstant

oaSupFanEndUse=choice

End use to which fan energy is recorded (in METER specified by oaSupFanMtr). See METER for available end use choices.

UnitsLegal RangeDefaultRequiredVariability
end use choiceFanNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
oFOutdoor dry-bulbNosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
\(\gt\) 0Outdoor humidity ratioNosubhourly

4.24.2 DOAS Exhaust Fan Data Members

oaExhFanVfDs=float

Exhaust fan design or rated flow at rated pressure.

UnitsLegal RangeDefaultRequiredVariability
cfmx \(\ge\) 0Sum of referencing IZXFER exhaust flowsNoconstant

oaExhFanPress=float

Design or rated fan pressure.

UnitsLegal RangeDefaultRequiredVariability
inches H2Ox \(>\) 00.3Noconstant

Only one of oaExhFanElecPwr, oaExhFanEff, and oaExhFanShaftBhp may be given.

oaExhFanElecPwr=float

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

UnitsLegal RangeDefaultRequiredVariability
W/cfmx \(>\) 0derived from oaExhFanEff and oaExhFanShaftBhpIf oaExhFanEff and oaExhFanShaftBhp not presentconstant

oaExhFanEff=float

Fan efficiency at design flow and pressure, as a fraction.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1derived from oaExhFanShaftBhp if given, else 0.08Noconstant

oaExhFanShaftBhp=float

Fan shaft brake horsepower at design flow and pressure.

UnitsLegal RangeDefaultRequiredVariability
bhpx \(>\) 0derived from oaExhFanEff.Noconstant

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:

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 00, 1, 0, 0, 0 (linear)Noconstant

oaExhFanMtr=mtrName

Name of meter, if any, to record energy used by exhaust fan. End use category used is specified by oaExhFanEndUse (next).

UnitsLegal RangeDefaultRequiredVariability
name of a METERnot recordedNoconstant

oaExhFanEndUse=choice

End use to which fan energy is recorded (in METER specified by oaExhFanMtr). See METER for available end use choices.

UnitsLegal RangeDefaultRequiredVariability
end use choiceFanNoconstant

4.24.3 DOAS Tempering Coils Data Members

oaSupTH=float

Heating setpoint for tempering and/or heat exchanger bypass.

UnitsLegal RangeDefaultRequiredVariability
oF68Nosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 00when modeling heating coilsubhourly

oaCoilHMtr=mtrName

Name of meter, if any, to record energy used by the heating coil.

UnitsLegal RangeDefaultRequiredVariability
name of a METERnot recordedNoconstant

oaSupTC=float

Cooling setpoint for tempering and/or heat exchanger bypass.

UnitsLegal RangeDefaultRequiredVariability
oF68Nosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 00when modeling cooling coilsubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\gt\) 01.0Nosubhourly

oaCoilCMtr=mtrName

Name of meter, if any, to record energy used by the cooling coil.

UnitsLegal RangeDefaultRequiredVariability
name of a METERnot recordedNoconstant

oaLoadMtr=ldMtrName

Name of load meter, if any, to record load met by the heating coil or cooling coil.

UnitsLegal RangeDefaultRequiredVariability
name of a LOADMETERnot recordedNoconstant

4.24.4 DOAS Heat Recovery Data Members

oaHXVfDs=float

Heat exchanger design or rated flow.

UnitsLegal RangeDefaultRequiredVariability
cfmx \(\gt\) 0Average of supply and exhaust fan design flowsNoconstant

oaHXf2=float

Heat exchanger flow fraction (of design flow) used for second set of effectivenesses.

UnitsLegal RangeDefaultRequiredVariability
0 \(\lt\) x \(\lt\) 1.00.75Noconstant

oaHXSenEffHDs=float

Heat exchanger sensible effectiveness in heating mode at the design flow rate. Specifying input triggers modeling of heat recovery.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1.0when modeling heat recoveryconstant

oaHXSenEffHf2=float

Heat exchanger sensible effectiveness in heating mode at the second flow rate (oaHXf2).

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1.00Noconstant

oaHXLatEffHDs=float

Heat exchanger latent effectiveness in heating mode at the design flow rate.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1.00Noconstant

oaHXLatEffHf2=float

Heat exchanger latent effectiveness in heating mode at the second flow rate (oaHXf2).

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1.00Noconstant

oaHXSenEffCDs=float

Heat exchanger sensible effectiveness in cooling mode at the design flow rate.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1.00Noconstant

oaHXSenEffCf2=float

Heat exchanger sensible effectiveness in cooling mode at the second flow rate (oaHXf2).

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1.00Noconstant

oaHXLatEffCDs=float

Heat exchanger latent effectiveness in cooling mode at the design flow rate.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1.00Noconstant

oaHXLatEffCf2=float

Heat exchanger latent effectiveness in cooling mode at the second flow rate (oaHXf2).

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1.00Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
NO, YESNONoconstant

oaHXAuxPwr=float

Auxiliary power required to operate the heat recovery device (e.g., wheel motor, contorls).

UnitsLegal RangeDefaultRequiredVariability
Wx \(\ge\) 00Nosubhourly

oaHXAuxMtr=mtrName

Name of meter, if any, to record energy used by auxiliary components of the heat recovery system.

UnitsLegal RangeDefaultRequiredVariability
name of a METERnot recordedNoconstant

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”.

UnitsLegal RangeDefaultRequiredVariability
N/ANoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

rsType=choice

Type of system.

rsTypeDescription
ACFURNACECompressor-based cooling and fuel-fired heating. Primary heating input energy is accumulated to end use HTG of meter rsFuelMtr.
ACRESISTANCECompressor-based cooling and electric (‘strip’) heating. Primary heating input energy is accumulated to end use HTG of meter rsElecMtr.
ASHPAir-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).
ASHPKGROOMPackaged room air-source heat pump.
ASHPHYDRONICAir-to-water heat pump with hydronic distribution. Compressor performance is approximated using the air-to-air model with adjusted efficiencies.
VCHP2Air-to-air heat pump with variable speed compressor.
WSHPWater-to-air heat pump.
ACCompressor-based cooling; no heating. Required ratings are SEER and capacity and EER at 95 oF outdoor dry bulb.
ACPKGROOMPackaged compressor-based cooling; no heating. Required ratings are capacity and EER at 95 oF outdoor dry bulb.
FURNACEFuel-fired heating. Primary heating input energy is accumulated to end use HTG of meter rsFuelMtr.
RESISTANCEElectric heating. Primary heating input energy is accumulated to end use HTG of meter rsElecMtr.
ACPKGROOMFURNACEPackaged room cooling and (separate) furnace heating.
ACPKGROOMRESISTANCEPackaged room cooling and electric resistance heating.
COMBINEDHEATDHWCombined heating / DHW. Use rsCHDHWSYS to specify the DHWSYS that provides hot water to the coil in this RSYS. No cooling.
ACCOMBINEDHEATDHWCompressor-based cooling plus COMBINEDHEATDHW heating.
FANCOILCoil-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.
UnitsLegal RangeDefaultRequiredVariability
one of above choicesACFURNACENoconstant

rsDesc=string

Text description of system, included as documentation in debugging reports such as those triggered by rsPerfMap=YES

UnitsLegal RangeDefaultRequiredVariability
stringnoneNoconstant

rsModeCtrl=choice

Specifies systems heating/cooling availability during simulation.

OFFSystem is off (neither heating nor cooling is available)
HEATSystem can heat (assuming rsType can heat)
COOLSystem can cool (assuming rsType can cool)
AUTOSystem can either heat or cool (assuming rsType compatibility). First request by any zone served by this RSYS determines mode for the current time step.
UnitsLegal RangeDefaultRequiredVariability
OFF, HEAT, COOL, AUTOAUTONohourly

rsPerfMap=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.

UnitsLegal RangeDefaultRequiredVariability
YES, NONONoconstant

rsFanTy=choice

Specifies fan (blower) position relative to cooling coil.

UnitsLegal RangeDefaultRequiredVariability
BLOWTHRU, DRAWTHRUBLOWTHRUNoconstant

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.

PSCPermanent split capacitor
BPMBrushless permanent magnet (aka ECM)
UnitsLegal RangeDefaultRequiredVariability
PSC, BPMPSCNoconstant

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).

UnitsLegal RangeDefaultRequiredVariability
name of a METERnoneNoconstant

rsFuelMtr =mtrName

Name of METER object, if any, by which system’s fuel energy use is recorded (under appropriate end uses).

UnitsLegal RangeDefaultRequiredVariability
name of a METERnoneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a LOADMETERnoneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Name of a LOADMETERNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Name of DHWSYSnoneif combined heat/DHWconstant

rsAFUE=float

Heating Annual Fuel Utilization Efficiency (AFUE).

UnitsLegal RangeDefaultRequiredVariability
0 \(<\) x \(\le\) 10.9 if furnace, 1.0 if resistanceNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btu/hrAUTOSIZE or x \(\ge\) 00Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
oFx \(>\) 030 oF if heat pump else 50 oFNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01.4Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
W/cfmx \(\ge\) 0see aboveNoconstant

rsHSPF=float

For rsType=ASHP, Heating Seasonal Performance Factor (HSPF).

UnitsLegal RangeDefaultRequiredVariability
Btu/Whx \(>\) 0noneYes if rsType=ASHPconstant

rsCAP115=float

For rsType=ASHP, rated heating capacity at outdoor dry-bulb temperature = 115 oF.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Calculated from rsCAP95Noconstant

rsCAP82=float

For rsType=ASHP, rated heating capacity at outdoor dry-bulb temperature = 82 oF.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Calculated from rsCAP95Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
Btu/WhAUTOSIZE or x \(>\) 0Calculated from rsCapCNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btu/Whx \(>\) 0Calculated from rsCap47 and rsCap17Noconstant

rsCap17=float

For rsType=ASHP, rated heating capacity at outdoor dry-bulb temperature = 17 oF.

UnitsLegal RangeDefaultRequiredVariability
Btu/Whx \(>\) 0Calculated from rsCap47Noconstant

rsCAP05=float

For rsType=ASHP, rated heating capacity at outdoor dry-bulb temperature = 5 oF.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Calculated from rsCAP47Noconstant

rsCOP115=float

For rsType=ASHP, rated heating coefficient of performance at outdoor dry-bulb temperature = 115 oF.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Calculated from rsCap115Noconstant

rsCOP95=float

For rsType=ASHP, rated heating coefficient of performance at outdoor dry-bulb temperature = 95 oF.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Calculated from rsCap95Noconstant

rsCOP82=float

For rsType=ASHP, rated heating coefficient of performance at outdoor dry-bulb temperature = 82 oF.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Calculated from rsCap82Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Estimated from rsHSPF, rsCap47, and rsCap17Noconstant

rsCOP35=float

For rsType=ASHP, rated heating coefficient of performance at outdoor dry-bulb temperature = 35 oF.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Calculated from rsCap35, rsCap47, rsCap17, rsCOP47, and rsCOP17Noconstant

rsCOP17=float

For rsType=ASHP, rated heating coefficient of performance at outdoor dry-bulb temperature = 17 oF.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Calculated from rsHSPF, rsCap47, and rsCap17Noconstant

rsCOP05=float

For rsType=ASHP, rated heating coefficient of performance at outdoor dry-bulb temperature = 5 oF.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Calculated from rsCap05Noconstant

rsCapRat1747=float

Ratio of rsCAP17 over rsCAP47.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Based on HSPF or other correlationsNoStart 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).

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0See aboveNoconstant

rsCapRat0547=float

Ratio of rsCAP05 over rsCAP47.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00Norun start time

rsCapRat11595=float

Ratio of rsCAP115 over rsCAP95.

UnitsLegal RangeDefaultRequiredVariability
0 \(<\) x \(\geq\) 10.9155Norun start time

rsCapRat8295=float

Ratio of rsCAP82 over rsCAP95.

UnitsLegal RangeDefaultRequiredVariability
1 \(\leq\) x \(<\) 21.06Norun start time

rsCapRatCH=float

For WSHP only: ratio of rsCapC to rsCapH. Used to derive capacity during autosizing or when only one capacity is specified.

UnitsLegal RangeDefaultRequiredVariability
.3 \(\leq\) x \(<\) 20.8NoStart of a run

rsCOPMin115=float

Coefficient of performance at outdoor dry-bulb temperature of 115 oF, minimum speed.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Calculated from rsCAP115, rsCOP115NoBefore set up or at the end of interval

rsCOPMin95=float

Coefficient of performance at outdoor dry-bulb temperature of 95 oF, minimum speed.

UnitsLegal RangeDefaultRequiredVariability
Calculated from rsCAP95, rsCOP950.0NoBefore set up or at the end of interval

rsCOPMin82=float

Coefficient of performance at outdoor dry-bulb temperature of 82 oF, minimum speed.

UnitsLegal RangeDefaultRequiredVariability
Calculated from rsCAP82, rsCOP820.0NoBefore set up or at the end of interval

rsCOPMin47=float

Coefficient of performance at outdoor dry-bulb temperature of 47 oF, minimum speed.

UnitsLegal RangeDefaultRequiredVariability
Calculated from rsCAP47, rsCOP47rsCOP47NoBefore set up or at the end of interval

rsCOPMin35=float

Coefficient of performance at outdoor dry-bulb temperature of 35 oF, minimum speed.

UnitsLegal RangeDefaultRequiredVariability
Calculated from rsCAP35, rsCOP35Derived from rsCAP47 and rsCAP17NoBefore set up or at the end of interval

rsCOPMin17=float

Coefficient of performance at outdoor dry-bulb temperature of 17 oF, minimum speed.

UnitsLegal RangeDefaultRequiredVariability
Calculated from rsCAP17, rsCOP17rsCOP17NoBefore set up or at the end of interval

rsCOPMin05=float

Coefficient of performance at outdoor dry-bulb temperature of 5 oF, minimum speed.

UnitsLegal RangeDefaultRequiredVariability
Calculated from rsCAP05, rsCOP05rsCOP05NoBefore set up or at the end of interval

rsloadFMin115=float

Ratio of total cooling capacity at minimum (non-cycling) speed to full-speed total cooling capacity at 115 oF outdoor dry bulb temperature.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01.0NoBefore set up or at the end of interval

rsloadFMin95=float

Ratio of total cooling capacity at minimum (non-cycling) speed to full-speed total cooling capacity at 95 oF outdoor dry bulb temperature.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01.0NoBefore set up or at the end of interval

rsloadFMin82=float

Ratio of total cooling capacity at minimum (non-cycling) speed to full-speed total cooling capacity at 82 oF outdoor dry bulb temperature.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01.0NoBefore set up or at the end of interval

rsloadFMin47=float

Ratio of heating capacity at minimum (non-cycling) speed to full-speed total cooling capacity at 47 oF outdoor dry bulb temperature.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01.0NoBefore set up or at the end of interval

rsloadFMin17=float

Ratio of heating capacity at minimum (non-cycling) speed to full-speed total cooling capacity at 17 oF outdoor dry bulb temperature.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01.0NoBefore set up or at the end of interval

rsloadFMin05=float

Ratio of heating capacity at minimum (non-cycling) speed to full-speed total cooling capacity at 5 oF outdoor dry bulb temperature.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01.0NoBefore set up or at the end of interval

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).

ChoiceDescription
NONENo auxiliary heat
RESISTANCEElectric resistance (aka strip heat)
FURNACEFuel-fired
UnitsLegal RangeDefaultRequiredVariability
See table aboveRESISTANCENoconstant

rsCtrlAuxH=choice

For rsType=ASHP, type of auxiliary heating control.

ChoiceDescription
LOCKOUTCompressor locked out if any auxiliary heating control
CYCLECompressor runs continuously and auxiliary cycles
ALTERNATEAlternates between compressor and auxiliary
UnitsLegal RangeDefaultRequiredVariability
See table aboveALTERNATE if rsTypeAuxH=FURNACE else CYCLENoStart 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).

UnitsLegal RangeDefaultRequiredVariability
Btu/hrAUTOSIZE or x \(\ge\) 00Noconstant

rsAFUEAuxH=float

For rsType=ASHP, auxiliary heat annualized fuel utilization efficiency.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.9 if rsTypeAuxH=FURNACE else 1Noconstant

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.

REVCYCLEReverse compressor (cooling) operation. Net capacity and efficiency is derived from rsCap17/rsCOP17 and rsCap35/rsCOP35 using linear interpolation. Auxiliary heat is not modeled.
REVCYCLEAUXReverse 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.
UnitsLegal RangeDefaultRequiredVariability
one of above choicesREVCYCLEAUXNoconstant

rsSHRtarget=float

Nominal target for sensible heat ratio (for fancoil).

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.7Nosubhour

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

rsSEER=float

Cooling rated Seasonal Energy Efficiency Ratio (SEER).

UnitsLegal RangeDefaultRequiredVariability
Btu/Whx \(>\) 0noneYesconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btu/Whx \(>\) 0Estimated from SEER unless WSHPYes for WSHP else Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
Btu/hrAUTOSIZE or x \(\le\) 0 (x \(>\) 0 coverted to \(<\) 0)noneYes if rsType includes coolingconstant

rsTdDesC=float

Nominal cooling temperature fall (across system, not zone) used during autosizing (when capacity is not yet known).

UnitsLegal RangeDefaultRequiredVariability
oFx \(<\) 0-25Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01.4Noconstant

rsFChg=float

Cooling compressor capacity factor. The gross cooling capacity is adjusted by the factor rsFChg as specified by California Title 24 procedures.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01 (no effect)Noconstant

rsVFPerTon=float

Standard air volumetric flow rate per nominal ton of cooling capacity.

UnitsLegal RangeDefaultRequiredVariability
cfm/ton150 \(\le\) x \(\le\) 500350Noconstant

rsFanPwrC=float

Cooling fan power.

UnitsLegal RangeDefaultRequiredVariability
W/cfmx \(\ge\) 00.365Noconstant

rsASHPLockOutT=float

Source air dry-bulb temperature below which the air source heat pump compressor does not operate.

UnitsLegal RangeDefaultRequiredVariability
oF(no lockout)Nohourly

rsCdH=float

Heating cyclic degradation coefficient, valid only for compressor-based heating (heat pumps).

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 0.5ASHPHYDRONIC: 0.25 ASHP: derived from rsHSPFNohourly

rsCdC=float

Cooling cyclic degradation coefficient, valid for configurations having compressor-based cooling.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 0.50Nohourly

rsFEffH=float

Heating efficiency factor. At each time step, the heating efficiency is multiplied by rsFEffH.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Nosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Nosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Nosubhourly

rsFEffC=float

Cooling efficiency factor. At each time step, the cooling efficiency is multiplied by rsEffC.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Nosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
Btu/hrx \(\ge\) 0no heating: 0 heat pump: rsCap47 (input or AUTOSIZEd) other: rsCapH (input or AUTOSIZEd)Nodaily

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.

UnitsLegal RangeDefaultRequiredVariability
Btu/hrx \(\ge\) 0no cooling: 0 other: rsCap95 (input or AUTOSIZEd)Nodaily

rsDSEH=float

Heating distribution system efficiency. If given, (1-rsDSEH) of RSYS heating output is discarded. Cannot be combined with more detailed DUCTSEG model.

UnitsLegal RangeDefaultRequiredVariability
0 < x < 1(use DUCTSEG model)Nohourly

rsDSEC=float

Cooling distribution system efficiency. If given, (1-rsDSEC) of RSYS cooling output is discarded. Cannot be combined with more detailed DUCTSEG model.

UnitsLegal RangeDefaultRequiredVariability
0 < x < 1(use DUCTSEG model)Nohourly

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.

NONENo CFI ventilation capabilities
FIXEDFixed-flow CFI (aka SmartVent). The specified rsOAVVfDs is used whenever the RSYS operates in OAV mode.
VARIABLEVariable-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.
UnitsLegal RangeDefaultRequiredVariability
NONE, FIXED, VARIABLEnoneNoconstant

rsOAVVfDs=float

Design air volume flow rate when RSYS is operating in OAV mode.

UnitsLegal RangeDefaultRequiredVariability
cfmx \(\ge\) 0noneif rsOAVType $ e$ NONEconstant

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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.2Noconstant

rsOAVFanPwr=float

RSYS OAV-mode fan power.

UnitsLegal RangeDefaultRequiredVariability
W/cfm0 < x \(\le\) 5per rsOAVTYPE FIXED: rsFanPwrC VARIABLE: NightBreeze vendor curve based on rsOAVvfDsNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\ge\) 0Dry-bulb temperature from weather fileNohourly

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.

UnitsLegal RangeDefaultRequiredVariability
oFx \(>\) 05 oFNohourly

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.

UnitsLegal RangeDefaultRequiredVariability
name of ZONEnoneif rsOAVType $ e$ NONEconstant

rsParElec=float

Parasitic electrical power. rsParElec is unconditionally accumulated to rsElecMtr (if specified) and has no other effect.

UnitsLegal RangeDefaultRequiredVariability
W0Nohourly

rsParFuel=float

Parasitic fuel use. rsParFuel is unconditionally accumulated to rsFuelMtr (if specified) and has no other effect.

UnitsLegal RangeDefaultRequiredVariability
Btuh0Nohourly

rsRhIn=float

Entering air relative humidity (for model testing).

UnitsLegal RangeDefaultRequiredVariability
W/cfm0 \(\le\) x \(\le\) 1Derived from entering air stateNoconstant

rsTdbOut=float

Air dry-bulb temperature at the outdoor portion of this system.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\ge\) 0From weather fileNohourly

endRSYS

Optionally indicates the end of the RSYS definition.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

dsTy=choice

Duct segment type.

UnitsLegal RangeDefaultRequiredVariability
SUPPLY, RETURNYesconstant

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 –

dsBranchLen=float

Average branch length.

UnitsLegal RangeDefaultRequiredVariability
ftx \(>\) 0-1.0Noconstant

dsBranchCount=integer

Number of branches.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0-1Noconstant

dsBranchCFA=float

Floor area served per branch

UnitsLegal RangeDefaultRequiredVariability
ft2x \(>\) 0-1.0Noconstant

dsAirVelDs=float

Specified air velocity design.

UnitsLegal RangeDefaultRequiredVariability
fpmx \(>\) 0-1.0Noconstant

dsExArea=float

Duct segment surface area at outside face of insulation for flat duct shape, see above.

UnitsLegal RangeDefaultRequiredVariability
ft2x \(\ge\) 0noneNoconstant

dsInArea=float

Duct segment inside surface area (at duct wall, duct wall thickness assumed negligible) for round shaped duct.

UnitsLegal RangeDefaultRequiredVariability
ft2x \(\ge\) 0Derived from dsDiameter and dsLength(see above reduct shape)constant

dsDiameter=float

Duct segment round duct diameter (duct wall thickness assumed negligible)

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 0Derived from dsInArea and dsLength(see above reduct shape)constant

dsLength=float

Duct segment length.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 0Derived from dsInArea and dsDiameter(see above reduct shape)constant

dsExCnd=choice

Conditions surrounding duct segment.

UnitsLegal RangeDefaultRequiredVariability
ADIABATIC, AMBIENT, SPECIFIEDT, ADJZNADJZNNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a ZONEnoneRequired when dsExCon = ADJZNconstant

dsEpsLW=float

Exposed (i.e. insulation) outside surface exterior long wave (thermal) emittance.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 10.9Noconstant

dsExT=float

Air dry-bulb temperature surrounding duct segment.

UnitsLegal RangeDefaultRequiredVariability
oFunrestrictednoneRequired if sfExCnd = SPECIFIEDThourly

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).

UnitsLegal RangeDefaultRequiredVariability
ft2-oF-hr / Btux \(\ge\) 00Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a MATERIALfiberglassNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
0 \(<\) x \(\le\) 1noneNoconstant

dsExH=float

Outside (exposed) surface convection coefficient.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(\ge\) 0.54Nosubhourly

endDuctSeg

Optionally indicates the end of the DUCTSEG definition.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

4.27 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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneYesconstant

wduMult=float

Scale factor applied to all draws in this DHWDAYUSE.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

4.28 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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

wuStart=float

The starting time of the hot water draw.

UnitsLegal RangeDefaultRequiredVariability
hr0 \(\le\) x \(\le\) 24noneYesconstant

wuDuration=float

Draw duration. wuDuration = 0 is equivalent to omitting the DHWUSE. Durations that extend beyond midnight are included in the current day.

UnitsLegal RangeDefaultRequiredVariability
min0 \(\le\) x \(\le\) 14400Nohourly

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.

UnitsLegal RangeDefaultRequiredVariability
gpmx \(\le\) 00Nohourly

wuHotF=float

Fraction of draw that is hot water. Cannot be specified with wuTemp or wuHeatRecEF.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 11Nohourly

wuTemp=float

Mixed-water use temperature at the fixture. Cannot be specified when wuHotF is given.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\le\) 00when 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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 0.90Nohourly

wuHWEndUse=choice

Hot-water end use: one of Shower, Bath, CWashr, DWashr, or Faucet. wuHWEndUse has the following functions –

UnitsLegal RangeDefaultRequiredVariability
One of above choices(use allocated to Unknown)Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 00Noconstant

endDHWUSE

Optionally indicates the end of the DHWUSE definition.

UnitsLegal RangeDefaultRequiredVariability
noneNo

Related Probes:

4.29 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.

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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

wsCalcMode=choice

Enables preliminary simulation that derives values needed for simulation.

PRERUNCalculate 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).
SIMULATEPerform full modeling calculations

To use PRERUN efficiently, the recommended input file structure is:

This order avoids duplicate time-consuming simulation of the full building model.

UnitsLegal RangeDefaultRequiredVariability
Codes listed aboveSIMULATENo

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.

UnitsLegal RangeDefaultRequiredVariability
name of a DHWSYSDHWSYS is standaloneNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a DHWSYSNo shared loadsNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
oF\(>\) 32 oFMains temp from weather fileNohourly

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).

UnitsLegal RangeDefaultRequiredVariability
oF\(>\) 32 oFNosubhourly

wsTInletDes=float

Cold water inlet design temperature for sizing.

UnitsLegal RangeDefaultRequiredVariability
oFx \(>\) 32 oFAnnual minimums mains temperatureNoconstant

wsUse=float

Hourly hot water use (at the point of use). See further info under wsDayUse.

UnitsLegal RangeDefaultRequiredVariability
galx \(\ge\) 00Nohourly

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).

UnitsLegal RangeDefaultRequiredVariability
galx \(\ge\) 0Nosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
name of a DHWDAYUSE(no scheduled draws)Nodaily

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).

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 00.0NoHourly

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).

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 00.0NoHourly

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).

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 00.0NoHourly

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).

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 01.0NoHourly

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).

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 01.0NoHourly

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).

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 00.0NoHourly

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.

UnitsLegal RangeDefaultRequiredVariability
gal/drawx \(\geq\) 00.0NoHourly

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.

UnitsLegal RangeDefaultRequiredVariability
gal/drawx \(\geq\) 00.0NoHourly

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.

UnitsLegal RangeDefaultRequiredVariability
gal/drawx \(\geq\) 00.0NoHourly

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.

UnitsLegal RangeDefaultRequiredVariability
gal/drawx \(\geq\) 00.0NoHourly

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.

UnitsLegal RangeDefaultRequiredVariability
gal/drawx \(\geq\) 00.0NoHourly

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.

UnitsLegal RangeDefaultRequiredVariability
gal/drawx \(\geq\) 00.0NoHourly

wsTRLTest=float

Circulation loop return temperature for testing and validation.

UnitsLegal RangeDefaultRequiredVariability
Fx \(\geq\) 00.0NoSubhourly

wsVolRLTest=float

Circulation loop volume flow rate for testing and validation.

UnitsLegal RangeDefaultRequiredVariability
gpmx \(\geq\) 00.0NoSubhourly

wsBranchModel=choice

Branch model selection.

wsBranchModelDescription
T24DHWModel in appendix B of the Alternative Compliance Manual
DRAWWASTEDraw duration increase per draw waste
DAYWASTEdraw duration increase per day waste

wsDayWasteVol=float

Average amount of waste per day.

UnitsLegal RangeDefaultRequired**Variability
gal/dayx \(\ge\) 0wsDayWasteBranchVolF * (Total DHWLOOPBRANCH vol)Noconstant

wsDayWasteBranchVolF=float

Day waste scaling factor.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Noconstant

wsFaucetDayWasteF=float

Relative faucet water draw for day of waste scheme.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.0Nosubhourly

wsShowerDayWasteF=float

Relative shower water draw for day of waste scheme.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.0Nosubhourly

wsBathDayWasteF=float

Relative bath water draw for day of waste scheme.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.0Nosubhourly

wsCWashrDayWasteF=float

Relative clothes washer water draw for day of waste scheme.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.0Nosubhourly

wsDWashrDayWasteF=float

Relative dish washer water draw for day of waste scheme.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.0Nosubhourly

wsUnkDayWasteF=float

Unknown relative water draw for day of waste scheme.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.0Nosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
oF\(>\) 32 oF120Nohourly

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).

UnitsLegal RangeDefaultRequiredVariability
oF\(>\) 32 oFNosubhourly

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.

UnitsLegal RangeDefaultRequiredVariability
oF\(>\) 32 oFwsTUseNohourly

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.

UnitsLegal RangeDefaultRequiredVariability
oF\(>\) 32 oFwsTSetPointNohourly

wsTSetpointDes=float

Specifies the design (sizing) set point temperature.

UnitsLegal RangeDefaultRequiredVariability
oFx \(>\) 32 oFwsTUseNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
galx \(>\) 00.0Noconstant

wsASHPTSrcDes=float

Design (sizing) source air temperature for HPWH DHWHEATERs.

UnitsLegal RangeDefaultRequiredVariability
oFx \(>\) 32 oFHeating design temperatureNoAt 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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01.0Noconstant

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.

wsDRMethodDescription
NONENone (default setpoint-based control)
SCHEDULEDemand response schedule (see wsDRSignal)
STATEOFCHARGEState-of-charge (see wsTargetSOC)
UnitsLegal RangeDefaultRequiredVariability
See table aboveNONENoconstant

wsDRSignal=choice

When (and only when) wsDRMethod=SCHEDULE, wsDRSignal allows hourly specification of modified control schemes. Available signals are:

wsDRSignalDescription
ONNormal operation following the water heater’s internal control logic.
TOOTops 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).
TOOLORTops off the tank once and locks out the resistance elements (only the compressor is used to heat the tank to setpoint).
TOOLOCTops off the tank once and locks out the compressor (only the resistance elements are used to heat the tank to setpoint).
TOTTops 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.
TOTLORTops of the tank on a timer and locks out the resistance elements (only the compressor is used to heat the tank to setpoint).
TOTLOCTops of the tank on a timer and locks out the compressor (only the resistance elements are used to heat the tank to setpoint).
LOCLocks out the compressor from the water heater’s normal internal control logic.
LORLocks out the resistive elements from the water heater’s normal internal control logic.
LOCLORLocks 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.

UnitsLegal RangeDefaultRequiredVariability
See Table aboveONNohourly

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))
UnitsLegal RangeDefaultRequiredVariability
0 \(\lt\) x \(\le\) 10.9Nohourly

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.

UnitsLegal RangeDefaultRequiredVariability
\(>\) 01Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
\(>\) 01Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Nohourly

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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 0.99Nohourly

wsSolarSys=dhwSolarSys

Name of DHWSOLARSYS object, if any, that supplies pre-heated water to this DHWSYS.

UnitsLegal RangeDefaultRequiredVariability
name of a DHWSOLARSYSnot recordedNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Wx \(\ge\) 00Nohourly

wsDrawMaxDur=integer

Maximum draw duration for the sizing window.

UnitsLegal RangeDefaultRequiredVariability
Hrx \(\geq\) 04Noconstant

wsLoadMaxDur=integer

Maximum load duration for the sizing window.

UnitsLegal RangeDefaultRequiredVariability
Hrx \(\geq\) 012Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a METERnot recordedNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a METERnot recordedNoconstant

wsWHhwMtr=dhwmtrName

Name of DHWMETER object, if any, to which hot water quantities (at water heater) are recorded by hot water end use.

UnitsLegal RangeDefaultRequiredVariability
name of a METERnot recordedNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a METERNoconstant

wsWriteDrawCSV=choice

If Yes, a comma-separated file is generated containing 1-minute interval hot water draw values for testing or linkage purposes.

UnitsLegal RangeDefaultRequiredVariability
Yes or NoNoNoconstant

endDHWSys

Optionally indicates the end of the DHWSYS definition.

UnitsLegal RangeDefaultRequiredVariability
noneNo

Related Probes:

4.30 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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

whMult=integer

Number of identical water heaters of this type. Any value \(>1\) is equivalent to repeated entry of the same DHWHEATER.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

whType=choice

Type of water heater. This categorization is based on CEC and federal rating standards that change from time to time.

SMALLSTORAGEA 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.
LARGESTORAGEAny storage water heater that is not SMALLSTORAGE.
SMALLINSTANTANEOUSA 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.
LARGEINSTANTANEOUSAn instantaneous water heater that does not conform to the definition of SMALLINSTANTANEOUS, an indirect fuel-fired water heater, or a hot water supply boiler.
INSTANTANEOUSUEFAn instantaneous water heater having a UEF rating (as opposed to EF).
UnitsLegal RangeDefaultRequiredVariability
Codes listed aboveSMALLSTORAGENoconstant

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.

RESISTANCEElectric resistance heating element Deprecated for whType=SMALLSTORAGE (use RESISTANCEX)
RESISTANCEXElectric resistance heating element, detailed HPWH model
ASHPAir source heat pump, EF model Deprecated for whType=SMALLSTORAGE (use ASHPX)
ASHPXAir source heat pump, detailed HPWH model
FUELFuel-fired burner
UnitsLegal RangeDefaultRequiredVariability
Codes listed aboveFUELNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Typical SwingTankTypicalNoconstant

whHeatingCap=float

Nominal heating capacity, available only for a limited HPWH types.

UnitsLegal RangeDefaultRequiredVariability
Btuhx \(>\) 00Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
gal\(\ge\) 0.1 (caution: small values may cause runtime errors)per whASHPType if HPWH else 50For some HPWH configurations, see aboveconstant

whVolRunning=float

Running storage volume is the volume above aquastat. Requires the total volume based on aquastat position. Ecotope’s HPWH tank and heater.

UnitsLegal RangeDefaultRequiredVariability
galx \(>\) 00Noconstant

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.

ConfigurationwhEF defaultUse
whType=SMALLSTORAGE, whHeatSrc=RESISTANCE or FUEL0.82Derivation of whLDEF
whType=SMALLSTORAGE, whHeatSrc=ASHP0.82Derivation 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 FUEL0.82Annual efficiency = whEF*0.92
Any other(unused)
UnitsLegal RangeDefaultRequiredVariability
\(>\) 0 Caution: maximum not checked. Unrealistic values will cause runtime errors and/or invalid resultsSee aboveSee aboveconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Calculated via DHWSYS PreRun mechanismWhen whType = SMALLSTORAGE and PreRun not usedconstant

whUEF=float

Water heater Uniform Energy Factor efficiency rating, used when whType=INSTANTANEOUSUEF.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 0nonewhen whType= INSTANTANEOUSUEFconstant

whAnnualElec=float

Annual electricity use assumed in UEF rating derivation. Used when whType=INSTANTANEOUSUEF.

UnitsLegal RangeDefaultRequiredVariability
kWhx \(\ge\) 0nonewhen whType= INSTANTANEOUSUEFconstant

whAnnualFuel=float

Annual fuel use assumd in UEF rating derivation, used when whType=INSTANTANEOUSUEF.

UnitsLegal RangeDefaultRequiredVariability
thermsx \(\ge\) 0nonewhen whType= INSTANTANEOUSUEFconstant

whRatedFlow=float

Maximum flow rate assumed in UEF rating derivation. Used when whType=INSTANTANEOUSUEF.

UnitsLegal RangeDefaultRequiredVariability
gpmx \(>\) 0nonewhen whType= INSTANTANEOUSUEFconstant

whStbyElec=float

Instantaneous water heater standby power (electricity consumed when heater is not operating). Used when whType=INSTANTANEOUSUEF.

UnitsLegal RangeDefaultRequiredVariability
Wx \(\ge\) 04Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a ZONENot in a zone (heat losses discarded)Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\ge\) 0whZone air temperature if specified, else 70 oFNohourly

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.

ChoiceSpecified type
GenericGeneral generic (parameterized by wh_EF and wh_vol)
AOSmithPHPT6060 gallon Voltex
AOSmithPHPT8080 gallon Voltex
AOSmithHPTU5050 gallon AOSmith HPTU
AOSmithHPTU6666 gallon AOSmith HPTU
AOSmithHPTU8080 gallon AOSmith HPTU
AOSmithHPTU80DR80 gallon AOSmith HPTU (demand reduction variant)
AOSmithCAHP120120 gallon AOSmith
Sanden40Sanden 40 gallon CO2 external heat pump
Sanden80Sanden 80 gallon CO2 external heat pump
Sanden120Sanden 120 gallon CO2 external heat pump
SandenGS3Sanden GS3 compressor CO2 external
GE20122012 era GeoSpring
GE20142014 80 gal GE model run in the efficiency mode
GE2014_80DR2014 80 gal GE model run in the efficiency mode (demand reduction variant)
GE2014StdMode2014 50 gal GE run in standard mode
GE2014StdMode802014 80 gal GE run in standard mode
RheemHB50newish Rheem (2014 model?)
RheemHBDR225050 gallon, 2250 W resistance Rheem HB Duct Ready
RheemHBDR455050 gallon, 4500 W resistance Rheem HB Duct Ready
RheemHBDR226565 gallon, 2250 W resistance Rheem HB Duct Ready
RheemHBDR456565 gallon, 4500 W resistance Rheem HB Duct Ready
RheemHBDR228080 gallon, 2250 W resistance Rheem HB Duct Ready
RheemHBDR458080 gallon, 4500 W resistance Rheem HB Duct Ready
Rheem2020Prem4040 gallon, Rheem 2020 Premium
Rheem2020Prem5050 gallon, Rheem 2020 Premium
Rheem2020Prem6565 gallon, Rheem 2020 Premium
Rheem2020Prem8080 gallon, Rheem 2020 Premium
Rheem2020Build4040 gallon, Rheem 2020 Builder
Rheem2020Build5050 gallon, Rheem 2020 Builder
Rheem2020Build6565 gallon, Rheem 2020 Builder
Rheem2020Build8080 gallon, Rheem 2020 Builder
RheemPlugInShared4040 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInShared5050 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInShared6565 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInShared8080 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInDedicated4040 gal Rheem plug-in 120V dedicated circuit (no resistance elements)
RheemPlugInDedicated5050 gal Rheem plug-in 120V dedicated circuit (no resistance elements)
Stiebel220EStiebel Eltron (2014 model?)
AOSmithSHPT50AOSmith add’l models (added 3-24-2017)
AOSmithSHPT66AOSmith add’l models (added 3-24-2017)
AOSmithSHPT80AOSmith add’l models (added 3-24-2017)
GenericTier1Generic Tier 1
GenericTier2Generic Tier 2
GenericTier3Generic Tier 3
GenericGeneral generic (parameterized by EF and vol)
UEF2GenericExperimental UEF=2
WorstCaseMediumUEF2Generic alias (supports pre-existing test cases)
BasicIntegratedTypical integrated HPWH
ResTankResistance heater (no compressor). Superceded by whHeatSrc=RESITANCEX
ResTankNoUAResistance heater (no compressor) with no tank losses. Superseded by whHeatSrc=RESISTANCEX.
AOSmithHPTU80DR80 gallon AOSmith HPTU with fixed backup setpoint (experimental for demand response testing)
AOSmithSHPT5050 gal AOSmith SHPT
AOSmithSHPT6666 gal AOSmith SHPT
AOSmithSHPT8080 gal AOSmith SHPT
ColmacCxV5_SPColmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA10_SPColmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA15_SPColmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA20_SPColmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA25_SPColmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA30_SPColmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxV5_MPColmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA10_MPColmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA15_MPColmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA20_MPColmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA25_MPColmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA30_MPColmac CxA-xx modular external HPWHs (multi-pass mode)
NyleC25A_SPNyle Cxx external HPWHs (SP = single pass mode)
NyleC60A_SPNyle Cxx external HPWHs (SP = single pass mode)
NyleC90A_SPNyle Cxx external HPWHs (SP = single pass mode)
NyleC125A_SPNyle Cxx external HPWHs (SP = single pass mode)
NyleC185A_SPNyle Cxx external HPWHs (SP = single pass mode)
NyleC250A_SPNyle Cxx external HPWHs (SP = single pass mode)
NyleC60A_CWP_SPNyle Cxx external SP HPWHs with cold weather package
NyleC90A_CWP_SPNyle Cxx external SP HPWHs with cold weather package
NyleC125A_CWP_SPNyle Cxx external SP HPWHs with cold weather package
NyleC185A_CWP_SPNyle Cxx external SP HPWHs with cold weather package
NyleC250A_CWP_SPNyle Cxx external SP HPWHs with cold weather package
NyleC60A_MPNyle Cxx external HPWHs (MP = multi-pass mode)
NyleC90A_MPNyle Cxx external HPWHs (MP = multi-pass mode)
NyleC125A_MPNyle Cxx external HPWHs (MP = multi-pass mode)
NyleC185A_MPNyle Cxx external HPWHs (MP = multi-pass mode)
NyleC250A_MPNyle Cxx external HPWHs (MP = multi-pass mode)
NyleC60A_CWP_MPNyle Cxx external MP HPWHs w/ cold weather package
NyleC90A_CWP_MPNyle Cxx external MP HPWHs w/ cold weather package
NyleC125A_CWP_MPNyle Cxx external MP HPWHs w/ cold weather package
NyleC185A_CWP_MPNyle Cxx external MP HPWHs w/ cold weather package
NyleC250A_CWP_MPNyle Cxx external MP HPWHs w/ cold weather package
Rheem_HPHD60HNU_MPRheem HPHD60 MP external MP HPWHs
Rheem_HPHD60VNU_MPRheem HPHD60 MP external MP HPWHs
Rheem_HPHD135HNU_MPRheem HPHD135 MP external MP HPWHs
Rheem_HPHD135VNU_MPRheem HPHD135 MP external MP HPWHs
Scalable_SPsingle pass scalable type for autosized standard design
Scalable_MPmultipass scalable type for autosized standard design
AquaThermAireVallara AquaThermAire HPWH
UnitsLegal RangeDefaultRequiredVariability
Codes listed abovenoneWhen whHeatSrc=ASHPXconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a ZONEwhZoneIf no zone is specified by input or default, heat extracted by ASHP has no effect.Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\ge\) 070 oF (used only when whASHPSrcZn and whZone not specified)Nohourly

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.

UnitsLegal RangeDefaultRequiredVariability
oCx \(\ge\) 07.22Noconstant

whResHtPwr=float

Specifies resistance upper element power, used only with whHeatSrc=RESISTANCEX.

UnitsLegal RangeDefaultRequiredVariability
Wx \(\ge\) 04500Noconstant

whResHtPwr2=float

Specifies resistance lower element power, used only with whHeatSrc=RESISTANCEX.

UnitsLegal RangeDefaultRequiredVariability
Wx \(\ge\) 0whResHtPwrNoconstant

whUA=float

HPWH-type total UA (not per tank)

UnitsLegal RangeDefaultRequiredVariability
Btuh/Fx \(\geq\) 0HPWH defaultNoconstant

whInsulR=float

Tank insulation resistance for heat pump water heater.

UnitsLegal RangeDefaultRequiredVariability
hr-F/Btuhx \(>\) 0-1Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1HPWH default (0?)Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
#x \(\geq\) 11Noconstant

whEff=float

Water heating efficiency, used in modeling whType=LARGESTORAGE and whType=LARGEINSTANTANEOUS.

UnitsLegal RangeDefaultRequiredVariability
0 \(<\) whEff \(\leq\) 1.82Noconstant

whSBL=float

Standby loss, used in modeling whType=LARGESTORAGE.

UnitsLegal RangeDefaultRequiredVariability
Btuhx \(\ge\) 00Noconstant

whPilotPwr=float

Pilot light consumption, included in fuel energy use of DHWHEATERs with whHeatSrc=FUEL.

UnitsLegal RangeDefaultRequiredVariability
Btuhx \(\ge\) 00Nohourly

whParElec=float

Parasitic electricity power, included in electrical energy use of all DHWHEATERs.

UnitsLegal RangeDefaultRequiredVariability
Wx \(\ge\) 00Nohourly

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.

UnitsLegal RangeDefaultRequiredVariability
\(\ge\) 01Nosubhourly

whElecMtr=mtrName

Name of METER object, if any, by which DHWHEATER electrical energy use is recorded (under end use DHW).

UnitsLegal RangeDefaultRequiredVariability
name of a METERParent DHWSYS wsElecMtrNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
end use code(extra backup accums to dhwBU)Noconstant

whFuelMtr =mtrName

Name of METER object, if any, by which DHWHEATER fuel energy use is recorded (under end use DHW).

UnitsLegal RangeDefaultRequiredVariability
name of a METERParent DHWSYS wsFuelMtrNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\gt\) 0Noconstant

endDHWHEATER

Optionally indicates the end of the DHWHEATER definition.

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 0noneNo

Related Probes:

4.31 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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

whMult=integer

Number of identical water heaters of this type. Any value \(>1\) is equivalent to repeated entry of the same DHWHEATER.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

whType=choice

Type of water heater. This categorization is based on CEC and federal rating standards that change from time to time.

SMALLSTORAGEA 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.
LARGESTORAGEAny storage water heater that is not SMALLSTORAGE.
SMALLINSTANTANEOUSA 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.
LARGEINSTANTANEOUSAn instantaneous water heater that does not conform to the definition of SMALLINSTANTANEOUS, an indirect fuel-fired water heater, or a hot water supply boiler.
INSTANTANEOUSUEFAn instantaneous water heater having a UEF rating (as opposed to EF).
UnitsLegal RangeDefaultRequiredVariability
Codes listed aboveSMALLSTORAGENoconstant

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.

RESISTANCEElectric resistance heating element Deprecated for whType=SMALLSTORAGE (use RESISTANCEX)
RESISTANCEXElectric resistance heating element, detailed HPWH model
ASHPAir source heat pump, EF model Deprecated for whType=SMALLSTORAGE (use ASHPX)
ASHPXAir source heat pump, detailed HPWH model
FUELFuel-fired burner
UnitsLegal RangeDefaultRequiredVariability
Codes listed aboveFUELNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Typical SwingTankTypicalNoconstant

whHeatingCap=float

Nominal heating capacity, available only for a limited HPWH types.

UnitsLegal RangeDefaultRequiredVariability
Btuhx \(>\) 00Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
gal\(\ge\) 0.1 (caution: small values may cause runtime errors)per whASHPType if HPWH else 50For some HPWH configurations, see aboveconstant

whVolRunning=float

Running storage volume is the volume above aquastat. Requires the total volume based on aquastat position. Ecotope’s HPWH tank and heater.

UnitsLegal RangeDefaultRequiredVariability
galx \(>\) 00Noconstant

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.

ConfigurationwhEF defaultUse
whType=SMALLSTORAGE, whHeatSrc=RESISTANCE or FUEL0.82Derivation of whLDEF
whType=SMALLSTORAGE, whHeatSrc=ASHP0.82Derivation 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 FUEL0.82Annual efficiency = whEF*0.92
Any other(unused)
UnitsLegal RangeDefaultRequiredVariability
\(>\) 0 Caution: maximum not checked. Unrealistic values will cause runtime errors and/or invalid resultsSee aboveSee aboveconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 0Calculated via DHWSYS PreRun mechanismWhen whType = SMALLSTORAGE and PreRun not usedconstant

whUEF=float

Water heater Uniform Energy Factor efficiency rating, used when whType=INSTANTANEOUSUEF.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 0nonewhen whType= INSTANTANEOUSUEFconstant

whAnnualElec=float

Annual electricity use assumed in UEF rating derivation. Used when whType=INSTANTANEOUSUEF.

UnitsLegal RangeDefaultRequiredVariability
kWhx \(\ge\) 0nonewhen whType= INSTANTANEOUSUEFconstant

whAnnualFuel=float

Annual fuel use assumd in UEF rating derivation, used when whType=INSTANTANEOUSUEF.

UnitsLegal RangeDefaultRequiredVariability
thermsx \(\ge\) 0nonewhen whType= INSTANTANEOUSUEFconstant

whRatedFlow=float

Maximum flow rate assumed in UEF rating derivation. Used when whType=INSTANTANEOUSUEF.

UnitsLegal RangeDefaultRequiredVariability
gpmx \(>\) 0nonewhen whType= INSTANTANEOUSUEFconstant

whStbyElec=float

Instantaneous water heater standby power (electricity consumed when heater is not operating). Used when whType=INSTANTANEOUSUEF.

UnitsLegal RangeDefaultRequiredVariability
Wx \(\ge\) 04Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a ZONENot in a zone (heat losses discarded)Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\ge\) 0whZone air temperature if specified, else 70 oFNohourly

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.

ChoiceSpecified type
GenericGeneral generic (parameterized by wh_EF and wh_vol)
AOSmithPHPT6060 gallon Voltex
AOSmithPHPT8080 gallon Voltex
AOSmithHPTU5050 gallon AOSmith HPTU
AOSmithHPTU6666 gallon AOSmith HPTU
AOSmithHPTU8080 gallon AOSmith HPTU
AOSmithHPTU80DR80 gallon AOSmith HPTU (demand reduction variant)
AOSmithCAHP120120 gallon AOSmith
Sanden40Sanden 40 gallon CO2 external heat pump
Sanden80Sanden 80 gallon CO2 external heat pump
Sanden120Sanden 120 gallon CO2 external heat pump
SandenGS3Sanden GS3 compressor CO2 external
GE20122012 era GeoSpring
GE20142014 80 gal GE model run in the efficiency mode
GE2014_80DR2014 80 gal GE model run in the efficiency mode (demand reduction variant)
GE2014StdMode2014 50 gal GE run in standard mode
GE2014StdMode802014 80 gal GE run in standard mode
RheemHB50newish Rheem (2014 model?)
RheemHBDR225050 gallon, 2250 W resistance Rheem HB Duct Ready
RheemHBDR455050 gallon, 4500 W resistance Rheem HB Duct Ready
RheemHBDR226565 gallon, 2250 W resistance Rheem HB Duct Ready
RheemHBDR456565 gallon, 4500 W resistance Rheem HB Duct Ready
RheemHBDR228080 gallon, 2250 W resistance Rheem HB Duct Ready
RheemHBDR458080 gallon, 4500 W resistance Rheem HB Duct Ready
Rheem2020Prem4040 gallon, Rheem 2020 Premium
Rheem2020Prem5050 gallon, Rheem 2020 Premium
Rheem2020Prem6565 gallon, Rheem 2020 Premium
Rheem2020Prem8080 gallon, Rheem 2020 Premium
Rheem2020Build4040 gallon, Rheem 2020 Builder
Rheem2020Build5050 gallon, Rheem 2020 Builder
Rheem2020Build6565 gallon, Rheem 2020 Builder
Rheem2020Build8080 gallon, Rheem 2020 Builder
RheemPlugInShared4040 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInShared5050 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInShared6565 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInShared8080 gal Rheem plug-in 120V shared circuit (no resistance elements)
RheemPlugInDedicated4040 gal Rheem plug-in 120V dedicated circuit (no resistance elements)
RheemPlugInDedicated5050 gal Rheem plug-in 120V dedicated circuit (no resistance elements)
Stiebel220EStiebel Eltron (2014 model?)
AOSmithSHPT50AOSmith add’l models (added 3-24-2017)
AOSmithSHPT66AOSmith add’l models (added 3-24-2017)
AOSmithSHPT80AOSmith add’l models (added 3-24-2017)
GenericTier1Generic Tier 1
GenericTier2Generic Tier 2
GenericTier3Generic Tier 3
GenericGeneral generic (parameterized by EF and vol)
UEF2GenericExperimental UEF=2
WorstCaseMediumUEF2Generic alias (supports pre-existing test cases)
BasicIntegratedTypical integrated HPWH
ResTankResistance heater (no compressor). Superceded by whHeatSrc=RESITANCEX
ResTankNoUAResistance heater (no compressor) with no tank losses. Superseded by whHeatSrc=RESISTANCEX.
AOSmithHPTU80DR80 gallon AOSmith HPTU with fixed backup setpoint (experimental for demand response testing)
AOSmithSHPT5050 gal AOSmith SHPT
AOSmithSHPT6666 gal AOSmith SHPT
AOSmithSHPT8080 gal AOSmith SHPT
ColmacCxV5_SPColmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA10_SPColmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA15_SPColmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA20_SPColmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA25_SPColmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxA30_SPColmac CxA-xx modular external HPWHs (single pass mode)
ColmacCxV5_MPColmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA10_MPColmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA15_MPColmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA20_MPColmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA25_MPColmac CxA-xx modular external HPWHs (multi-pass mode)
ColmacCxA30_MPColmac CxA-xx modular external HPWHs (multi-pass mode)
NyleC25A_SPNyle Cxx external HPWHs (SP = single pass mode)
NyleC60A_SPNyle Cxx external HPWHs (SP = single pass mode)
NyleC90A_SPNyle Cxx external HPWHs (SP = single pass mode)
NyleC125A_SPNyle Cxx external HPWHs (SP = single pass mode)
NyleC185A_SPNyle Cxx external HPWHs (SP = single pass mode)
NyleC250A_SPNyle Cxx external HPWHs (SP = single pass mode)
NyleC60A_CWP_SPNyle Cxx external SP HPWHs with cold weather package
NyleC90A_CWP_SPNyle Cxx external SP HPWHs with cold weather package
NyleC125A_CWP_SPNyle Cxx external SP HPWHs with cold weather package
NyleC185A_CWP_SPNyle Cxx external SP HPWHs with cold weather package
NyleC250A_CWP_SPNyle Cxx external SP HPWHs with cold weather package
NyleC60A_MPNyle Cxx external HPWHs (MP = multi-pass mode)
NyleC90A_MPNyle Cxx external HPWHs (MP = multi-pass mode)
NyleC125A_MPNyle Cxx external HPWHs (MP = multi-pass mode)
NyleC185A_MPNyle Cxx external HPWHs (MP = multi-pass mode)
NyleC250A_MPNyle Cxx external HPWHs (MP = multi-pass mode)
NyleC60A_CWP_MPNyle Cxx external MP HPWHs w/ cold weather package
NyleC90A_CWP_MPNyle Cxx external MP HPWHs w/ cold weather package
NyleC125A_CWP_MPNyle Cxx external MP HPWHs w/ cold weather package
NyleC185A_CWP_MPNyle Cxx external MP HPWHs w/ cold weather package
NyleC250A_CWP_MPNyle Cxx external MP HPWHs w/ cold weather package
Rheem_HPHD60HNU_MPRheem HPHD60 MP external MP HPWHs
Rheem_HPHD60VNU_MPRheem HPHD60 MP external MP HPWHs
Rheem_HPHD135HNU_MPRheem HPHD135 MP external MP HPWHs
Rheem_HPHD135VNU_MPRheem HPHD135 MP external MP HPWHs
Scalable_SPsingle pass scalable type for autosized standard design
Scalable_MPmultipass scalable type for autosized standard design
AquaThermAireVallara AquaThermAire HPWH
UnitsLegal RangeDefaultRequiredVariability
Codes listed abovenoneWhen whHeatSrc=ASHPXconstant

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.

UnitsLegal RangeDefaultRequiredVariability
name of a ZONEwhZoneIf no zone is specified by input or default, heat extracted by ASHP has no effect.Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\ge\) 070 oF (used only when whASHPSrcZn and whZone not specified)Nohourly

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.

UnitsLegal RangeDefaultRequiredVariability
oCx \(\ge\) 07.22Noconstant

whResHtPwr=float

Specifies resistance upper element power, used only with whHeatSrc=RESISTANCEX.

UnitsLegal RangeDefaultRequiredVariability
Wx \(\ge\) 04500Noconstant

whResHtPwr2=float

Specifies resistance lower element power, used only with whHeatSrc=RESISTANCEX.

UnitsLegal RangeDefaultRequiredVariability
Wx \(\ge\) 0whResHtPwrNoconstant

whUA=float

HPWH-type total UA (not per tank)

UnitsLegal RangeDefaultRequiredVariability
Btuh/Fx \(\geq\) 0HPWH defaultNoconstant

whInsulR=float

Tank insulation resistance for heat pump water heater.

UnitsLegal RangeDefaultRequiredVariability
hr-F/Btuhx \(>\) 0-1Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1HPWH default (0?)Noconstant

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).

UnitsLegal RangeDefaultRequiredVariability
#x \(\geq\) 11Noconstant

whEff=float

Water heating efficiency, used in modeling whType=LARGESTORAGE and whType=LARGEINSTANTANEOUS.

UnitsLegal RangeDefaultRequiredVariability
0 \(<\) whEff \(\leq\) 1.82Noconstant

whSBL=float

Standby loss, used in modeling whType=LARGESTORAGE.

UnitsLegal RangeDefaultRequiredVariability
Btuhx \(\ge\) 00Noconstant

whPilotPwr=float

Pilot light consumption, included in fuel energy use of DHWHEATERs with whHeatSrc=FUEL.

UnitsLegal RangeDefaultRequiredVariability
Btuhx \(\ge\) 00Nohourly

whParElec=float

Parasitic electricity power, included in electrical energy use of all DHWHEATERs.

UnitsLegal RangeDefaultRequiredVariability
Wx \(\ge\) 00Nohourly

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.

UnitsLegal RangeDefaultRequiredVariability
\(\ge\) 01Nosubhourly

whElecMtr=mtrName

Name of METER object, if any, by which DHWHEATER electrical energy use is recorded (under end use DHW).

UnitsLegal RangeDefaultRequiredVariability
name of a METERParent DHWSYS wsElecMtrNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
end use code(extra backup accums to dhwBU)Noconstant

whFuelMtr =mtrName

Name of METER object, if any, by which DHWHEATER fuel energy use is recorded (under end use DHW).

UnitsLegal RangeDefaultRequiredVariability
name of a METERParent DHWSYS wsFuelMtrNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\gt\) 0Noconstant

endDHWHEATER

Optionally indicates the end of the DHWHEATER definition.

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 0noneNo

Related Probes:

4.32 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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

wrMult=integer

Number of identical heat recovery devices of this type. Any value >1 is equivalent to repeated entry of the same DHWHEATREC.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
ShowerShowerNoconstant

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).

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Noconstant

wrFeedsWH=choice

Specifies whether the potable-side outlet of the DHWHEATREC is connected to the DHWHEATER(s) inlet.

UnitsLegal RangeDefaultRequiredVariability
Yes, NoNoNoconstant

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).

UnitsLegal RangeDefaultRequiredVariability
Vertical, Horizontal, SetEFVerticalNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 1noneYeshourly

wrTDInDiff=float

Temperature drop between the fixture drain and DHWHEATREC drain-side inlet. The drain-side inlet temperature is thus DHWUSE wuTemp - wrTDInDiff.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\ge\) 04.6 oFNohourly

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.

UnitsLegal RangeDefaultRequiredVariability
oFx \(>\) 065 oFNohourly

endDHWHEATREC

Optionally indicates the end of the DHWHEATREC definition.

UnitsLegal RangeDefaultRequiredVariability
noneNo

Related Probes:

4.33 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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

wtMult=integer

Number of identical tanks of this type. Any value \(>1\) is equivalent to repeated entry of the same DHWTANK.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Btuh/oFx \(\ge\) 0Derived from wtVol and wtInsulRNoconstant

wtVol=float

Specifies tank volume.

UnitsLegal RangeDefaultRequiredVariability
galx \(\ge\) 00Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
ft2-oF/Btuhx \(\ge\) 0.010Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Name of ZONE0Noconstant

wtTEx=float

Tank surround temperature.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\ge\) 070Nohourly

wtTTank=float

Tank average water temperature.

UnitsLegal RangeDefaultRequiredVariability
oF\(>\) 32 oFParent DHWSYSTEM wsTUseNohourly

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.

UnitsLegal RangeDefaultRequiredVariability
Btuh(any)0Nohourly

endDHWTank

Optionally indicates the end of the DHWTANK definition.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

4.34 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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

wpMult=integer

Number of identical pumps of this type. Any value \(>1\) is equivalent to repeated entry of the same DHWPUMP.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

wpPwr=float

Pump power.

UnitsLegal RangeDefaultRequiredVariability
Wx \(>\) 00Nohourly

wpElecMtr=mtrName

Name of METER object, if any, to which DHWPUMP electrical energy use is recorded (under end use DHW).

UnitsLegal RangeDefaultRequiredVariability
name of a METERParent DHWSYS wsElecMtrNoconstant

endDHWPump

Optionally indicates the end of the DHWPUMP definition.

UnitsLegal RangeDefaultRequiredVariability
noneNo

Related Probes:

4.35 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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

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).

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

wlFlow=float

Loop flow rate (when operating).

UnitsLegal RangeDefaultRequiredVariability
gpmx \(\ge\) 06Nohourly

wlTIn1=float

Inlet temperature of first DHWLOOPSEG.

UnitsLegal RangeDefaultRequiredVariability
oFx \(>\) 0DHWSYS wsTUseNohourly

wlRunF=float

Fraction of hour that loop circulation operates.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Nohourly

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).

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Wx \(\ge\) 00Nohourly

wlLossMakeupEff=float

Specifies the efficiency of loss makeup heating if any. No effect when wlLossMakeupPwr is 0.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Nohourly

wlElecMtr=mtrName

Name of METER object, if any, to which DHWLOOP electrical energy use is recorded (under end use dhwMFL).

UnitsLegal RangeDefaultRequiredVariability
name of a METERParent DHWSYS wsElecMtrNoconstant

endDHWLoop

Optionally indicates the end of the DHWLOOP definition.

UnitsLegal RangeDefaultRequiredVariability
noneNo

Related Probes:

4.36 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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

wlpMult=integer

Number of identical pumps of this type. Any value \(>1\) is equivalent to repeated entry of the same DHWPUMP.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

wlpPwr=float

Pump power.

UnitsLegal RangeDefaultRequiredVariability
Wx \(>\) 00Nohourly

wlpLiqHeatF=float

Fraction of pump power that heats circulating liquid. The remainder is discarded.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 11Nohourly

wlpElecMtr=mtrName

Name of METER object, if any, to which DHWLOOPPUMP electrical energy use is recorded (under end use dhwMFL).

UnitsLegal RangeDefaultRequiredVariability
name of a METERParent DHWLOOP wlElecMtrNoconstant

endDHWLOOPPUMP

Optionally indicates the end of the DHWPUMP definition.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

4.37 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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

wgTy=choice

Specifies the type of segment. RETURN segments, if any, must follow SUPPLY segments.

SUPPLYIndicates a supply segment (flow is sum of circulation and draw flow, child DHWLOOPBRANCHs permitted).
RETURNIndicates a return segment (flow is only due to circulation, child DHWLOOPBRANCHs not allowed)
UnitsLegal RangeDefaultRequiredVariability
noneYesconstant

wgLength=float

Length of segment.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Noconstant

wgSize=float

Nominal size of pipe. CSE assumes the pipe outside diameter = size + 0.125 in.

UnitsLegal RangeDefaultRequiredVariability
inx \(>\) 01Yesconstant

wgInsulK=float

Pipe insulation conductivity

UnitsLegal RangeDefaultRequired**Variability
Btuh-ft/ft2-oFx \(>\) 00.02167Noconstant

wgInsulThk=float

Pipe insulation thickness

UnitsLegal RangeDefaultRequiredVariability
inx \(\ge\) 01Noconstant

wgExH=float

Combined radiant/convective exterior surface conductance between insulation (or pipe if no insulation) and surround.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 01.5Nohourly

wgExT=float

Surrounding equivalent temperature.

UnitsLegal RangeDefaultRequiredVariability
oFx \(>\) 070Nohourly

wgFNoDraw=float

Fraction of hour when no draw occurs.

UnitsLegal RangeDefaultRequiredVariability
oFx \(>\) 070Nohourly

endDHWLoopSeg

Optionally indicates the end of the DHWLOOPSEG definition.

UnitsLegal RangeDefaultRequiredVariability
noneNo

Related Probes:

4.38 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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

wbMult=float

Specifies the number of identical DHWLOOPBRANCHs. Note may be non-integer.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01Noconstant

wbLength=float

Length of branch.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\ge\) 00Noconstant

wbSize=float

Nominal size of pipe. CSE assumes the pipe outside diameter = size + 0.125 in.

UnitsLegal RangeDefaultRequiredVariability
inx \(>\) 0noneYesconstant

wbInsulK=float

Pipe insulation conductivity

UnitsLegal RangeDefaultRequired**Variability
Btuh-ft/ft2-oFx \(>\) 00.02167Noconstant

wbInsulThk=float

Pipe insulation thickness

UnitsLegal RangeDefaultRequiredVariability
inx \(\ge\) 01Noconstant

wbExH=float

Combined radiant/convective exterior surface conductance between insulation (or pipe if no insulation) and surround.

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-oFx \(>\) 01.5Nohourly

wbExCnd=choice

Specify exterior conditions.

ChoiceDescription
ADIABATICAdiabatic on other side
AMBIENTAmbient exterior
SPECTSpecify temperature
ADJZNAdjacent zone
GROUNDGround conditions
UnitsLegal RangeDefaultRequiredVariability
See table aboveSPECTNoconstant

wbAdjZn=float

Boundary conditions for adjacent zones.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.0Norunly

wbExTX=float

External boundary conditions.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 070.0Norunly

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)

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 01Noconstant

wbExT=float

Surrounding equivalent temperature.

UnitsLegal RangeDefaultRequiredVariability
oFx \(>\) 070Nohourly

wbFlow=float

Branch flow rate assumed during draw.

UnitsLegal RangeDefaultRequiredVariability
gpmx \(\ge\) 02Nohourly

wbFWaste=float

Number of times during the hour when the branch volume is discarded.

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 00Nohourly

endDHWLOOPBRANCH

Optionally indicates the end of the DHWLOOPBRANCH definition.

UnitsLegal RangeDefaultRequiredVariability
nonenoneNo

Related Probes:

4.39 DHWSOLARSYS

Solar water heating system.

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 ???).

UnitsLegal RangeDefaultRequiredVariability
oFname of a METERnot recordedNoconstant

swSCFluidSpHt=float

Specific heat for the collector fluid.

UnitsLegal RangeDefaultRequiredVariability
Btu/lbm-oFx \(>\) 00.9Noconstant

swSCFluidDens=float

Density for the collector fluid.

UnitsLegal RangeDefaultRequiredVariability
lb/ft3x \(>\) 064.0Noconstant

swEndUse

End use of pump energy; defaults to “DHW”.

swParElec=float

UnitsLegal RangeDefaultRequiredVariability
x \(\ge\) 00Nohourly

swTankHXEff=float

Tank heat exchanger effectiveness.

UnitsLegal RangeDefaultRequiredVariability
0 \(\le\) x \(\le\) 0.990Nohourly

swTankTHxLimit=float

Temperature limit for the tank collector.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\geq\) 0180.0Noconstant

swTankUA=float

Heat transfer coefficient for the tank multiplied by area.

UnitsLegal RangeDefaultRequiredVariability
Btuh/oFNoconstant

swTankVol=float

UnitsLegal RangeDefaultRequiredVariability
galNoconstant

swTankInsulR=float

Total tank insulation resistance, built-in plus exterior wrap.

UnitsLegal RangeDefaultRequiredVariability
ft2-oF/BtuhNoconstant

swTankZone=znName

Pointer to tank zone location, use sw_tankTEx if NULL

UnitsLegal RangeDefaultRequiredVariability
Name of ZONENoconstant

swTankTEx=float

Surrounding temperature.

UnitsLegal RangeDefaultRequiredVariability
oFNohourly

endDHWSOLARSYS

Optionally indicates the end of the DHWSOLARSYS definition.

UnitsLegal RangeDefaultRequiredVariability
noneNo

4.40 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.

UnitsLegal RangeDefaultRequiredVariability
ft^2\(>\) 00Yesconstant

scMult

Number of identical collectors, default 1

UnitsLegal RangeDefaultRequiredVariability
\(>\) 01Noconstant

scTilt=float

Array tilt.

UnitsLegal RangeDefaultRequiredVariability
deg0Yesconstant

scAzm=float

Array azimuth.

UnitsLegal RangeDefaultRequiredVariability
deg0Yesconstant

scFRUL=float

Fit slope

UnitsLegal RangeDefaultRequiredVariability
Btuh/ft2-o^F-0.727Noconstant

scFRTA=float

Fit y-intercept

UnitsLegal RangeDefaultRequiredVariability
none\(>\) 00.758Noconstant

scTestMassFlow=flaot

Mass flow rate for collector loop SRCC rating.

UnitsLegal RangeDefaultRequiredVariability
lb/h-ft2x \(>\) 014.79Noconstant

scKta60=float

Incident angle modifier at 60 degree, from SRCC rating.

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 00.72Noconstant

scOprMassFlow=float

Collector loop operating mass flow rate.

UnitsLegal RangeDefaultRequiredVariability
lb/h-ft2x \(>\) 00.0Noconstant

scPipingLength=float

Collector piping length.

UnitsLegal RangeDefaultRequiredVariability
ftx \(\geq\) 00.0NoHourly and at the end of interval

scPipingInsulK=float

Collector piping insulation conductivity.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 00.02167NoHourly and at the end of interval

scPipingInsulThk=float

Collector piping insulation thickness.

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 01.0NoHourly and at the end of interval

scPipingExH=float

Collector piping heat transfer coefficient.

UnitsLegal RangeDefaultRequiredVariability
x \(>\) 01.5NoHourly and at the end of interval

scPipingExT=float

Collector piping surround temperature.

UnitsLegal RangeDefaultRequiredVariability
oFx \(\geq\) 3270.0Nohourly

scPumpPwr=float

UnitsLegal RangeDefaultRequiredVariability
Btu/hx \(\ge\) 0from scPumpflowNoconstant

scPumpLiqHeatF=float

Fraction of scPumpPwr added to liquid stream, the remainder is discarded.

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 01.0NoEvery run

scPumpOnDeltaT=float

Temperature difference between the tank and collector outlet where pump turns on

UnitsLegal RangeDefaultRequiredVariability
oF10.0Noconstant

scPumpOffDeltaT=float

Temperature difference between the tank and collector outlet where pump turns off

UnitsLegal RangeDefaultRequiredVariability
oF5.0Noconstant

endDHWSOLARCOLLECTOR

Optionally indicates the end of the DHWSOLARCOLLECTOR definition.

UnitsLegal RangeDefaultRequiredVariability
noneNo

4.41 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.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

pvElecMtr=choice

Name of meter by which this PVARRAY’s AC power out is recorded. Generated power is expressed as a negative value.

UnitsLegal RangeDefaultRequiredVariability
name of a METERnoneNoconstant

pvEndUse=choice

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

ClgCooling
HtgHeating (includes heat pump compressor)
HPBUHeat pump resistance heating (backup and defrost)
DHWDomestic (service) hot water
DHWBUDomestic (service) hot water heating backup (HPWH resistance)
DHWMFLDomestic (service) hot water heating multi-family loop pumping and loss makeup
FANCFans, AC and cooling ventilation
FANHFans, heating
FANVFans, IAQ venting
FANFans, other purposes
AUXHVAC auxiliaries such as pumps
PROCProcess
LITLighting
RCPReceptacles
EXTExterior lighting
REFRRefrigeration
DISHDishwashing
DRYClothes drying
WASHClothes washing
COOKCooking
USER1User-defined category 1
USER2User-defined category 2
BTBattery charge power
PVPhotovoltaic power generation
UnitsLegal RangeDefaultRequiredVariability
Codes listed abovePVNoconstant

pvDCSysSize=float

The rated photovoltaic system DC capacity/size as indicated by the nameplate.

UnitsLegal RangeDefaultRequiredVariability
kWx \(\geq\) 0noneYesconstant

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 TypepvCoverRefrIndpvTempCoeff
Standard1.3-0.00206
Premium1.3-0.00194
ThinFilm1.3-0.00178
CustomUser-definedUser-defined
UnitsLegal RangeDefaultRequiredVariability
Standard Premium ThinFilm CustomStandardNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 01.3Noconstant

pvTempCoeff=float

The temperature coefficient how the efficiency of the module varies with the cell temperature. Values are typically negative.

UnitsLegal RangeDefaultRequiredVariability
1/oFno restrictions-0.00206Noconstant

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.

UnitsLegal RangeDefaultRequired**Variability
FixedOpenRack, FixedRoofMount, OneAxisTracking, TwoAxisTrackingFixedOpenRackNoconstant

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.

UnitsLegal RangeDefaultRequiredVariability
degreesunrestrictedfrom pvVertices (if given) else 0Nohourly

The following figures illustrate the use of both pvTilt and pvAzm for various configurations:

Fixed, south facing, tilted at 40o
Fixed, south facing, tilted at 40o
One-axis tracker, south facing, tilted at 20o
One-axis tracker, south facing, tilted at 20o
One-axis tracker, horizontal aligned North/South (more common)
One-axis tracker, horizontal aligned North/South (more common)
One-axis tracker, horizontal aligned East/West (less common)
One-axis tracker, horizontal aligned East/West (less common)

pvAzm=float

Photovoltaic array azimuth (0 = north, 90 = east, etc.). If a value outside the range 0o \(\leq\) x \(<\) 360o 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.

UnitsLegal RangeDefaultRequiredVariability
degreesunrestrictedfrom pvVertices (if given) else 0Nohourly

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
UnitsLegal RangeDefaultRequiredVariability
ftunrestrictedno polygon9, 12, 15, 18, 21, 24, 27, 30, 33, or 36 valuesconstant

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.

UnitsLegal RangeDefaultRequiredVariability
x \(\geq\) 1.01.2Noconstant

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.

UnitsLegal RangeDefaultRequiredVariability
Building or SiteBuildingNoconstant

pvGrndRefl=float

Ground reflectance used for calculating reflected solar incidence on the array.

UnitsLegal RangeDefaultRequiredVariability
0 \(<\) x \(<\) 1.00.2Nohourly

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.

UnitsLegal RangeDefaultRequiredVariability
x > 0.01.2Noconstant

pvInverterEff=float

AC inverter efficiency at rated DC power.

UnitsLegal RangeDefaultRequiredVariability
0 \(<\) x \(<\) 1.00.96Noconstant

pvSysLosses=float

Fraction of total DC energy lost. The total loss from a system is aggregated from several possible causes as illustrated below:

Loss TypeDefault Assumption
Soiling0.02
Shading0 (handled explicitly)
Snow0
Mismatch0 (shading mismatch handled explicitly [see pvSIF])
Wiring0.02
Connections0.005
Light-induced degradation0.015
Nameplate rating0.01
Age0.05 (estimated 0.5% degradation over 20 years)
Availability0.03
Total0.14

Italic lines indicate differences from PVWatts assumptions.

UnitsLegal RangeDefaultRequiredVariability
0 \(<\) x \(<\) 1.00.14Nohourly

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.

UnitsLegal RangeDefaultRequiredVariability
noneNoconstant

Related Probes:

4.42 SHADEX

SHADEX describes an object that shades other building surfaces using an advanced shading model. Advanced shading calculations are provided only for PVARRAYs. Advanced shading must be enabled via Top exShadeModel.

sxName

Name of photovoltaic array. Give after the word SHADEX.

UnitsLegal RangeDefaultRequiredVariability
63 charactersnoneNoconstant

sxMounting=choice

Specifies the mounting location of the shade. sxMounting=Site indicates the SHADEX position is fixed and is not modified if the building is rotated. The position of SHADEXs with sxMounting=Building are modified to include the effect of building rotation specified via Top bldgAz

UnitsLegal RangeDefaultRequiredVariability
Building or SiteSiteNoconstant

sxVertices=list of up to 36 floats

Vertices of a polygon representing the shape of the shading object.

The values that follow sxVertices are a series of X, Y, and Z values for the vertices of the polygon. The coordinate system is defined from a viewpoint facing no