HVACTEMPLATE:SYSTEM:UNITARYSYSTEM

Unitary HVAC system with optional cooling and heating. Supports DX and chilled water, cooling, gas, electric, and hot water heating, air-to-air and water-to-air heat pumps.

Name

System Availability Schedule Name

Control Type

Type: choice (Load or SetPoint)
Load control requires a Controlling Zone name. SetPoint control requires set points at coil outlet nodes. The user must add appropriate SetpointManager objects to the idf file.
Default: Load

Control Zone or Thermostat Location Name

Type: list of objects ( or ZONE)
This field is required if Control Type is Load.

Cooling Supply Air Flow Rate

Type: real number
Supply air flow rate during cooling operation This field may be set to "autosize". If a value is entered, it will *not* be multiplied by any sizing factor or by zone multipliers. If using zone multipliers a value entered here must be large enough to serve the multiplied zones.
Unit: m3/s
Default: autosize

Heating Supply Air Flow Rate

Type: real number
Supply air flow rate during heating operation This field may be set to "autosize". If a value is entered, it will *not* be multiplied by any sizing factor or by zone multipliers. If using zone multipliers a value entered here must be large enough to serve the multiplied zones.
Unit: m3/s
Default: autosize

No Load Supply Air Flow Rate

Type: real number
Supply air flow rate when no cooling or heating is needed Only used when heat pump fan operating mode is Continuous. This air flow rate is used when no heating or cooling is required and the DX coil compressor is off. If this field is left blank or zero, the supply air flow rate from the previous on cycle (either cooling or heating) is used. This field may be set to "autosize". If a value is entered, it will *not* be multiplied by any sizing factor or by zone multipliers. If using zone multipliers a value entered here must be large enough to serve the multiplied zones.
Unit: m3/s
Minimum: 0
Default: autosize

Supply Fan Operating Mode Schedule Name

Type: list of objects (SCHEDULE:YEAR, SCHEDULE:FILE, SCHEDULE:COMPACT, EXTERNALINTERFACE:FUNCTIONALMOCKUPUNITIMPORT:TO:SCHEDULE, EXTERNALINTERFACE:SCHEDULE or SCHEDULE:CONSTANT)
Refers to a schedule to specify unitary supply fan operating mode. Schedule values of 0 indicate cycling fan (auto) Schedule values of 1 indicate continuous fan (on) If this field is left blank, a schedule of always zero (cycling fan) will be used.

Supply Fan Placement

Type: choice (BlowThrough or DrawThrough)
Default: BlowThrough

Supply Fan Total Efficiency

Maximum: 1.0
Default: 0.7

Supply Fan Delta Pressure

Unit: Pa
Minimum: 0
Default: 600

Supply Fan Motor Efficiency

Maximum: 1.0
Default: 0.9

Supply Fan Motor in Air Stream Fraction

Minimum: 0.0
Maximum: 1.0
Default: 1.0

Cooling Coil Type

Type: choice (SingleSpeedDX, TwoSpeedDX, MultiSpeedDX, TwoStageDX, TwoStageHumidityControlDX, HeatExchangerAssistedDX, SingleSpeedDXWaterCooled, ChilledWater, ChilledWaterDetailedFlatModel, HeatExchangerAssistedChilledWater or None)
Default: SingleSpeedDX

Number of Speeds for Cooling

Type: integer
Used only for Cooling Coil Type = MultiSpeedDX.
Minimum: 0
Maximum: 4
Default: 1

Cooling Coil Availability Schedule Name

Type: list of objects (SCHEDULE:YEAR, SCHEDULE:FILE, SCHEDULE:COMPACT, EXTERNALINTERFACE:FUNCTIONALMOCKUPUNITIMPORT:TO:SCHEDULE, EXTERNALINTERFACE:SCHEDULE or SCHEDULE:CONSTANT)
If blank, always on

Cooling Design Supply Air Temperature

Used for sizing.
Unit: C
Default: 12.8

DX Cooling Coil Gross Rated Total Capacity

Total cooling capacity not accounting for the effect of supply air fan heat Rating point: air entering the cooling coil at 26.7 C dry-bulb/19.4 C wet-bulb, and air entering the outdoor condenser coil at 35 C dry-bulb/23.9 C wet-bulb
Unit: W
Default: autosize

DX Cooling Coil Gross Rated Sensible Heat Ratio

Rated sensible heat ratio (gross sensible capacity/gross total capacity) Sensible and total capacities do not include effect of supply fan heat
Minimum: 0.5
Maximum: 1.0
Default: autosize

DX Cooling Coil Gross Rated COP

Gross cooling capacity divided by power input to the compressor and outdoor fan, does not include supply fan heat or supply fan electric power input
Unit: W/W
Default: 3.0

Heating Coil Type

Type: choice (Electric, Gas, HotWater, SingleSpeedDXHeatPumpAirSource, MultiSpeedDXHeatPumpAirSource, SingleSpeedDXHeatPumpWaterSource, MultiStageElectric, MultiStageGas or None)
Default: Gas

Number of Speeds or Stages for Heating

Type: integer
Used only for Heating Coil Type = MultiSpeedDXHeatPumpAirSource), MultiStageElectric, or MultiStageGas.
Minimum: 0
Maximum: 4
Default: 1

Heating Coil Availability Schedule Name

Type: list of objects (SCHEDULE:YEAR, SCHEDULE:FILE, SCHEDULE:COMPACT, EXTERNALINTERFACE:FUNCTIONALMOCKUPUNITIMPORT:TO:SCHEDULE, EXTERNALINTERFACE:SCHEDULE or SCHEDULE:CONSTANT)
If blank, always on

Heating Design Supply Air Temperature

Used for sizing.
Unit: C
Default: 50.0

Heating Coil Gross Rated Capacity

Type: real number
Rated heating capacity excluding the effect of supply air fan heat Rating point outdoor dry-bulb temp 8.33 C, outdoor wet-bulb temp 6.11 C Rating point heating coil entering air dry-bulb 21.11 C, coil entering wet-bulb 15.55 C
Unit: W
Default: autosize

Gas Heating Coil Efficiency

Minimum: 0.0
Maximum: 1.0
Default: 0.8

Gas Heating Coil Parasitic Electric Load

Unit: W
Minimum: 0.0
Default: 0.0

Heat Pump Heating Coil Gross Rated COP

Heating Coil Rated Capacity divided by power input to the compressor and outdoor fan, does not include supply air fan heat or supply air fan electrical energy. Rating point outdoor dry-bulb temp 8.33 C, outdoor wet-bulb temp 6.11 C Rating point heating coil entering air dry-bulb 21.11 C, coil entering wet-bulb 15.55 C Applies only to DX coils
Unit: W/W
Default: 2.75

Heat Pump Heating Minimum Outdoor Dry-Bulb Temperature

Type: real number
Unit: C
Minimum: -20.0
Default: -8.0

Heat Pump Defrost Maximum Outdoor Dry-Bulb Temperature

Type: real number
Unit: C
Minimum: 0.0
Maximum: 7.22
Default: 5.0

Heat Pump Defrost Strategy

Type: choice (ReverseCycle or Resistive)
Default: ReverseCycle

Heat Pump Defrost Control

Type: choice (Timed or OnDemand)
Default: Timed

Heat Pump Defrost Time Period Fraction

Type: real number
Fraction of time in defrost mode only applicable if Timed defrost control is specified
Minimum: 0.0
Default: 0.058333

Supplemental Heating or Reheat Coil Type

Type: choice (Electric, Gas, HotWater, DesuperHeater or None)
Default: None

Supplemental Heating or Reheat Coil Availability Schedule Name

Type: list of objects (SCHEDULE:YEAR, SCHEDULE:FILE, SCHEDULE:COMPACT, EXTERNALINTERFACE:FUNCTIONALMOCKUPUNITIMPORT:TO:SCHEDULE, EXTERNALINTERFACE:SCHEDULE or SCHEDULE:CONSTANT)
If blank, always on

Supplemental Heating or Reheat Coil Capacity

Unit: W
Default: autosize

Supplemental Heating or Reheat Coil Maximum Outdoor Dry-Bulb Temperature

Type: real number
Supplemental heater will not operate when outdoor temperature exceeds this value.
Unit: C
Maximum: 21.0
Default: 21.0

Supplemental Gas Heating or Reheat Coil Efficiency

Applies only if Supplemental Heating Coil Type is Gas
Minimum: 0.0
Maximum: 1.0
Default: 0.8

Supplemental Gas Heating or Reheat Coil Parasitic Electric Load

Applies only if Supplemental Heating Coil Type is Gas
Unit: W
Minimum: 0.0
Default: 0.0

Maximum Outdoor Air Flow Rate

Unit: m3/s
Minimum: 0.0
Default: autosize

Minimum Outdoor Air Flow Rate

Unit: m3/s
Minimum: 0.0
Default: autosize

Minimum Outdoor Air Schedule Name

Economizer Type

Type: choice (FixedDryBulb, FixedEnthalpy, DifferentialDryBulb, DifferentialEnthalpy, FixedDewPointAndDryBulb, ElectronicEnthalpy, DifferentialDryBulbAndEnthalpy or NoEconomizer)
Default: NoEconomizer

Economizer Lockout

Type: choice (NoLockout, LockoutWithHeating or LockoutWithCompressor)
Default: NoLockout

Economizer Maximum Limit Dry-Bulb Temperature

Type: real number
Enter the maximum outdoor dry-bulb temperature limit for FixedDryBulb economizer control type. No input or blank input means this limit is not operative. Limit is applied regardless of economizer control type.
Unit: C

Economizer Maximum Limit Enthalpy

Type: real number
Enter the maximum outdoor enthalpy limit for FixedEnthalpy economizer control type. No input or blank input means this limit is not operative Limit is applied regardless of economizer control type.
Unit: J/kg

Economizer Maximum Limit Dewpoint Temperature

Type: real number
Enter the maximum outdoor dewpoint temperature limit for FixedDewPointAndDryBulb economizer control type. No input or blank input means this limit is not operative. Limit is applied regardless of economizer control type.
Unit: C

Economizer Minimum Limit Dry-Bulb Temperature

Type: real number
Enter the minimum outdoor dry-bulb temperature limit for economizer control. No input or blank input means this limit is not operative Limit is applied regardless of economizer control type.
Unit: C

Supply Plenum Name

Type: list of objects ( or ZONE)
Plenum zone name. Supply plenum serves all zones on this system. Blank if none.

Return Plenum Name

Type: list of objects ( or ZONE)
Plenum zone name. Return plenum serves all zones on this system. Blank if none.

Heat Recovery Type

Type: choice (None, Sensible or Enthalpy)
Default: None

Sensible Heat Recovery Effectiveness

Minimum: 0.0
Maximum: 1.0
Default: 0.70

Latent Heat Recovery Effectiveness

Applicable only if Heat Recovery Type is Enthalpy.
Minimum: 0.0
Maximum: 1.0
Default: 0.65

Heat Recovery Heat Exchanger Type

Type: choice (Plate or Rotary)
Default: Plate

Heat Recovery Frost Control Type

Type: choice (None, ExhaustAirRecirculation, ExhaustOnly or MinimumExhaustTemperature)
Default: None

Dehumidification Control Type

Type: choice (None, CoolReheat or Multimode)
None = meet sensible load only CoolReheat = cool beyond the dry-bulb setpoint, reheat with reheat coil If no reheat coil specified, cold supply temps may occur. Multimode = activate enhanced dehumidification mode as needed and meet sensible load. Valid only for Cooling Coil Type = TwoStageHumidityControlDX or HeatExchangerAssistedDX
Default: None

Dehumidification Relative Humidity Setpoint

Type: real number
Zone relative humidity setpoint in percent (0 to 100) Ignored if Dehumidification Relative Humidity Setpoint Schedule specified below
Unit: percent
Minimum: 0.0
Maximum: 100.0
Default: 60.0

Dehumidification Relative Humidity Setpoint Schedule Name

Type: list of objects (SCHEDULE:YEAR, SCHEDULE:FILE, SCHEDULE:COMPACT, EXTERNALINTERFACE:FUNCTIONALMOCKUPUNITIMPORT:TO:SCHEDULE, EXTERNALINTERFACE:SCHEDULE or SCHEDULE:CONSTANT)
Leave blank to use constant setpoint specified in Dehumidification Relative Humidity Setpoint above. Schedule values must be in percent relative humidity (0 to 100).

Humidifier Type

Type: choice (None or ElectricSteam)
Default: None

Humidifier Availability Schedule Name

Humidifier Rated Capacity

Type: real number
Moisture output rate at full rated power input. The humidifier does not currently autosize, so the default is very large to allow for adequate capacity.
Unit: m3/s
Minimum: 0.0
Default: 0.000001

Humidifier Rated Electric Power

Type: real number
Electric power input at rated capacity moisture output. Power consumption is proportional to moisture output with no part-load penalty.
Unit: W
Minimum: 0.0
Default: autosize

Humidifier Control Zone Name

Type: list of objects ( or ZONE)
Zone name where humidistat is located

Humidifier Relative Humidity Setpoint

Type: real number
Zone relative humidity setpoint in percent (0 to 100). Ignored if Humidifier Relative Humidity Setpoint Schedule specified below
Unit: percent
Minimum: 0.0
Maximum: 100.0
Default: 30.0

Humidifier Relative Humidity Setpoint Schedule Name

Type: list of objects (SCHEDULE:YEAR, SCHEDULE:FILE, SCHEDULE:COMPACT, EXTERNALINTERFACE:FUNCTIONALMOCKUPUNITIMPORT:TO:SCHEDULE, EXTERNALINTERFACE:SCHEDULE or SCHEDULE:CONSTANT)
Leave blank to use constant setpoint specified in Humidifier Relative Humidity Setpoint above.Schedule values must be in percent relative humidity (0 to 100).

Sizing Option

Type: choice (Coincident or NonCoincident)
Select whether autosized system supply flow rate is the sum of Coincident or NonCoincident zone air flow rates.
Default: NonCoincident

Return Fan

Type: choice (Yes or No)
Specifies if the system has a return fan.
Default: No

Return Fan Total Efficiency

Maximum: 1.0
Default: 0.7

Return Fan Delta Pressure

Unit: Pa
Minimum: 0
Default: 300

Return Fan Motor Efficiency

Maximum: 1.0
Default: 0.9

Return Fan Motor in Air Stream Fraction

Minimum: 0.0
Maximum: 1.0
Default: 1.0