CSE User's Manual

California Simulation Engine

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.

NONEDefrost is not modeled. When 17 oF < TDbO < 45 oF, capacity and efficiency are determined by interpolation using unmodified 17 oF and 47 oF data.
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: