Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
Zero-out the fields Outdoor Air Flow Rate During Cooling Operation, Outdoor Air Flow Rate During Heating Operation, and Outdoor Air Flow Rate When No Cooling or Heating is Needed so that the PTAC will never provide OA.
In the field Supply Air Fan Operating Mode Schedule, put a schedule that with a value of 0 (zero) for the whole year to tell the fan to cycle on only when heating or cooling is needed.
The EnergyPlus documentation for the ZoneHVAC:PackagedTerminalAirConditioner can be found here. In particular, these two fields are the key:
Field: Supply Air Fan Object Type This alpha field defines the type of fan used by this PTAC. The only valid choices are Fan:OnOff and Fan:ConstantVolume. A fan of type Fan:OnOff is used with cycling fan operating mode, and a fan of type> Fan:ConstantVolume is used with continuous fan operating mode (see Supply Air Fan Operating Mode Schedule field below). The input requirements for these fan objects are described elsewhere in this document.
and
Field: Supply Air Fan Operating Mode Schedule Name This alpha field specifies the name of the supply air fan operating mode schedule. The supply air fan operating mode may vary during the simulation based on time-of-day or with a change of season. Schedule values of 0 denote that the supply air fan and the heating or cooling coil cycle on and off together to meet the heating or cooling load (a.k.a. AUTO fan). Schedule values other than 0 denote that the supply fan runs continuously while the heating or cooling coil cycles to meet the load.
The PTAC currently in the OpenStudio library has a Fan:ConstantVolume in it, so it will not cycle. I have filed an issue so that we will add a cycling PTAC to the library for 1.7.0. In the meantime, as a workaround, you can manually add it to your library like this:
C:\Program Files\OpenStudio 1.6.0\share\openstudio-1.6.0\OSApp\hvaclibrary' and make a backup copy of 'hvac_library.osm in case you mess it up in the next step.hvac_library.osm in a text editor (like Notepad, etc.)hvac_library.osm, then save the file.`
OS:Schedule:Ruleset,
{94303a34-b4d5-4c03-b9d7-159d3c6cb998}, !- Handle
Cycling PTAC Fan Mode Always Zero, !- Name
{a39d697d-d9d7-4e6a-b699-6d03c9d0c642}, !- Schedule Type Limits Name
{abe962af-435d-47cc-be5d-c09ae79eae09}; !- Default Day Schedule Name
OS:Schedule:Day,
{abe962af-435d-47cc-be5d-c09ae79eae09}, !- Handle
Cycling PTAC Fan Mode Sch Default, !- Name
{a39d697d-d9d7-4e6a-b699-6d03c9d0c642}, !- Schedule Type Limits Name
, !- Interpolate to Timestep
24, !- Hour 1
0, !- Minute 1
0; !- Value Until Time 1
OS:Fan:OnOff,
{767b3df3-668f-4617-a401-010ddc2aa5b2}, !- Handle
Cycling PTAC Fan, !- Name
{9f54092d-a4a8-41b8-a381-c4c332ecb843}, !- Availability Schedule Name
0.6, !- Fan Efficiency
250, !- Pressure Rise {Pa}
autosize, !- Maximum Flow Rate {m3/s}
0.8, !- Motor Efficiency
1, !- Motor In Airstream Fraction
, !- Air Inlet Node Name
, !- Air Outlet Node Name
{bba01083-43f5-4ccb-8f1a-458c1d7291fe}, !- Fan Power Ratio Function of Speed Ratio Curve Name
{142613e7-7f8e-4f5e-987b-f414bfc1d546}, !- Fan Efficiency Ratio Function of Speed Ratio Curve Name
; !- End-Use Subcategory
OS:Curve:Exponent,
{bba01083-43f5-4ccb-8f1a-458c1d7291fe}, !- Handle
Fan On Off Power Curve, !- Name
1, !- Coefficient1 Constant
0, !- Coefficient2 Constant
0, !- Coefficient3 Constant
0, !- Minimum Value of x {BasedOnField A2}
1; !- Maximum Value of x {BasedOnField A2}
OS:Curve:Cubic,
{142613e7-7f8e-4f5e-987b-f414bfc1d546}, !- Handle
Fan On Off Efficiency Curve, !- Name
1, !- Coefficient1 Constant
0, !- Coefficient2 x
0, !- Coefficient3 x**2
0, !- Coefficient4 x**3
0, !- Minimum Value of x {BasedOnField A2}
1; !- Maximum Value of x {BasedOnField A2}
OS:Coil:Heating:Water,
{cf0eca3e-3f1d-4984-8a48-f141c87d20cf}, !- Handle
Cycling PTAC HW Htg Coil, !- Name
{9f54092d-a4a8-41b8-a381-c4c332ecb843}, !- Availability Schedule Name
, !- U-Factor Times Area Value {W/K}
, !- Maximum Water Flow Rate {m3/s}
, !- Water Inlet Node Name
, !- Water Outlet Node Name
, !- Air Inlet Node Name
, !- Air Outlet Node Name
, !- Performance Input Method
, !- Rated Capacity {W}
, !- Rated Inlet Water Temperature {C}
, !- Rated Inlet Air Temperature {C}
, !- Rated Outlet Water Temperature {C}
, !- Rated Outlet Air Temperature {C}
; !- Rated Ratio for Air and Water Convection
OS:Coil:Cooling:DX:SingleSpeed,
{6cbb9c74-47af-4064-ac48-02c1db36d3ec}, !- Handle
Cycling PTAC 1 Spd DX Clg Coil, !- Name
{9f54092d-a4a8-41b8-a381-c4c332ecb843}, !- Availability Schedule Name
autosize, !- Rated Total Cooling Capacity {W}
autosize, !- Rated Sensible Heat Ratio
3, !- Rated COP {W/W}
autosize, !- Rated Air Flow Rate {m3/s}
773.3, !- Rated Evaporator Fan Power Per Volume Flow Rate {W/(m3/s)}
, !- Air Inlet Node Name
, !- Air Outlet Node Name
{375c013f-f15f-4049-a1bd-7d4735fd5f45}, !- Total Cooling Capacity Function of Temperature Curve Name
{55d14754-fb2d-456e-b587-35c6637eea07}, !- Total Cooling Capacity Function of Flow Fraction Curve Name
{6a283d45-f313-45f4-8663-df4f7af800d7}, !- Energy Input Ratio Function of Temperature Curve Name
{0073a0c9-fad3-4684-b0fd-1c3c6cdbac05}, !- Energy Input Ratio Function of Flow Fraction Curve Name
{4b025358-5550-49ee-bfd6-f69f838f5675}, !- Part Load Fraction Correlation Curve Name
, !- Nominal Time for Condensate Removal to Begin {s}
, !- Ratio of Initial Moisture Evaporation Rate and Steady State Latent Capacity {dimensionless}
, !- Maximum Cycling Rate {cycles/hr}
, !- Latent Capacity Time Constant {s}
, !- Condenser Air Inlet Node Name
AirCooled, !- Condenser Type
0, !- Evaporative Condenser Effectiveness {dimensionless}
Autosize, !- Evaporative Condenser Air Flow Rate {m3/s}
Autosize, !- Evaporative Condenser Pump Rated Power Consumption {W}
0, !- Crankcase Heater Capacity {W}
0, !- Maximum Outdoor Dry-Bulb Temperature for Crankcase Heater Operation {C}
, !- Supply Water Storage Tank Name
, !- Condensate Collection Water Storage Tank Name
0, !- Basin Heater Capacity {W/K}
10, !- Basin Heater Setpoint Temperature {C}
; !- Basin Heater Operating Schedule Name
OS:Curve:Biquadratic,
{375c013f-f15f-4049-a1bd-7d4735fd5f45}, !- Handle
Curve Biquadratic 1, !- Name
0.942587793, !- Coefficient1 Constant
0.009543347, !- Coefficient2 x
0.00068377, !- Coefficient3 x**2
-0.011042676, !- Coefficient4 y
5.249e-006, !- Coefficient5 y**2
-9.72e-006, !- Coefficient6 x*y
17, !- Minimum Value of x {BasedOnField A2}
22, !- Maximum Value of x {BasedOnField A2}
13, !- Minimum Value of y {BasedOnField A3}
46; !- Maximum Value of y {BasedOnField A3}
OS:Curve:Quadratic,
{55d14754-fb2d-456e-b587-35c6637eea07}, !- Handle
Curve Quadratic 1, !- Name
0.8, !- Coefficient1 Constant
0.2, !- Coefficient2 x
0, !- Coefficient3 x**2
0.5, !- Minimum Value of x {BasedOnField A2}
1.5; !- Maximum Value of x {BasedOnField A2}
OS:Curve:Biquadratic,
{6a283d45-f313-45f4-8663-df4f7af800d7}, !- Handle
Curve Biquadratic 2, !- Name
0.342414409, !- Coefficient1 Constant
0.034885008, !- Coefficient2 x
-0.0006237, !- Coefficient3 x**2
0.004977216, !- Coefficient4 y
0.000437951, !- Coefficient5 y**2
-0.000728028, !- Coefficient6 x*y
17, !- Minimum Value of x {BasedOnField A2}
22, !- Maximum Value of x {BasedOnField A2}
13, !- Minimum Value of y {BasedOnField A3}
46; !- Maximum Value of y {BasedOnField A3}
OS:Curve:Quadratic,
{0073a0c9-fad3-4684-b0fd-1c3c6cdbac05}, !- Handle
Curve Quadratic 2, !- Name
1.1552, !- Coefficient1 Constant
-0.1808, !- Coefficient2 x
0.0256, !- Coefficient3 x**2
0.5, !- Minimum Value of x {BasedOnField A2}
1.5; !- Maximum Value of x {BasedOnField A2}
OS:Curve:Quadratic,
{4b025358-5550-49ee-bfd6-f69f838f5675}, !- Handle
Curve Quadratic 3, !- Name
0.85, !- Coefficient1 Constant
0.15, !- Coefficient2 x
0, !- Coefficient3 x**2
0, !- Minimum Value of x {BasedOnField A2}
1; !- Maximum Value of x {BasedOnField A2}
OS:ZoneHVAC:PackagedTerminalAirConditioner,
{85ac1ec0-b6ed-41a3-9de6-ebd31563fa9f}, !- Handle
Cycling PTAC DX Clg HW Htg, !- Name
{9f54092d-a4a8-41b8-a381-c4c332ecb843}, !- Availability Schedule Name
, !- Air Inlet Node Name
, !- Air Outlet Node Name
OutdoorAir:Mixer, !- Outdoor Air Mixer Object Type
, !- Outdoor Air Mixer Name
Autosize, !- Supply Air Flow Rate During Cooling Operation {m3/s}
Autosize, !- Supply Air Flow Rate During Heating Operation {m3/s}
Autosize, !- Supply Air Flow Rate When No Cooling or Heating is Needed {m3/s}
Autosize, !- Outdoor Air Flow Rate During Cooling Operation {m3/s}
Autosize, !- Outdoor Air Flow Rate During Heating Operation {m3/s}
Autosize, !- Outdoor Air Flow Rate When No Cooling or Heating is Needed {m3/s}
{767b3df3-668f-4617-a401-010ddc2aa5b2}, !- Supply Air Fan Name
{cf0eca3e-3f1d-4984-8a48-f141c87d20cf}, !- Heating Coil Name
{6cbb9c74-47af-4064-ac48-02c1db36d3ec}, !- Cooling Coil Name
DrawThrough, !- Fan Placement
{94303a34-b4d5-4c03-b9d7-159d3c6cb998}; !- Supply Air Fan Operating Mode Schedule Name
OS:ScheduleTypeLimits,
{a39d697d-d9d7-4e6a-b699-6d03c9d0c642}, !- Handle
ControlMode, !- Name
0, !- Lower Limit Value {BasedOnField A4}
1, !- Upper Limit Value {BasedOnField A4}
Discrete, !- Numeric Type
ControlMode; !- Unit Type
| | 2 | No.2 Revision |
Zero-out the fields Outdoor Air Flow Rate During Cooling Operation, Outdoor Air Flow Rate During Heating Operation, and Outdoor Air Flow Rate When No Cooling or Heating is Needed so that the PTAC will never provide OA.
In the field Supply Air Fan Operating Mode Schedule, put a schedule that with a value of 0 (zero) for the whole year to tell the fan to cycle on only when heating or cooling is needed.
The EnergyPlus documentation for the ZoneHVAC:PackagedTerminalAirConditioner can be found here. In particular, these two fields are the key:
Field: Supply Air Fan Object Type This alpha field defines the type of fan used by this PTAC. The only valid choices are Fan:OnOff and Fan:ConstantVolume. A fan of type Fan:OnOff is used with cycling fan operating mode, and a fan of type> Fan:ConstantVolume is used with continuous fan operating mode (see Supply Air Fan Operating Mode Schedule field below). The input requirements for these fan objects are described elsewhere in this document.
and
Field: Supply Air Fan Operating Mode Schedule Name This alpha field specifies the name of the supply air fan operating mode schedule. The supply air fan operating mode may vary during the simulation based on time-of-day or with a change of season. Schedule values of 0 denote that the supply air fan and the heating or cooling coil cycle on and off together to meet the heating or cooling load (a.k.a. AUTO fan). Schedule values other than 0 denote that the supply fan runs continuously while the heating or cooling coil cycles to meet the load.
The PTAC currently in the OpenStudio library has a Fan:ConstantVolume in it, so it will not cycle. I have filed an issue so that we will add a cycling PTAC to the library for 1.7.0. In the meantime, as a workaround, you can manually add it to your library like this:
C:\Program Files\OpenStudio 1.6.0\share\openstudio-1.6.0\OSApp\hvaclibrary' and make a backup copy of 'hvac_library.osm in case you mess it up in the next step.hvac_library.osm in a text editor (like Notepad, etc.)hvac_library.osm, then save the /Program Files/, you may need to have admin rights to save changes.`
OS:Schedule:Ruleset,
{94303a34-b4d5-4c03-b9d7-159d3c6cb998}, !- Handle
Cycling PTAC Fan Mode Always Zero, !- Name
{a39d697d-d9d7-4e6a-b699-6d03c9d0c642}, !- Schedule Type Limits Name
{abe962af-435d-47cc-be5d-c09ae79eae09}; !- Default Day Schedule Name
OS:Schedule:Day,
{abe962af-435d-47cc-be5d-c09ae79eae09}, !- Handle
Cycling PTAC Fan Mode Sch Default, !- Name
{a39d697d-d9d7-4e6a-b699-6d03c9d0c642}, !- Schedule Type Limits Name
, !- Interpolate to Timestep
24, !- Hour 1
0, !- Minute 1
0; !- Value Until Time 1
OS:Fan:OnOff,
{767b3df3-668f-4617-a401-010ddc2aa5b2}, !- Handle
Cycling PTAC Fan, !- Name
{9f54092d-a4a8-41b8-a381-c4c332ecb843}, !- Availability Schedule Name
0.6, !- Fan Efficiency
250, !- Pressure Rise {Pa}
autosize, !- Maximum Flow Rate {m3/s}
0.8, !- Motor Efficiency
1, !- Motor In Airstream Fraction
, !- Air Inlet Node Name
, !- Air Outlet Node Name
{bba01083-43f5-4ccb-8f1a-458c1d7291fe}, !- Fan Power Ratio Function of Speed Ratio Curve Name
{142613e7-7f8e-4f5e-987b-f414bfc1d546}, !- Fan Efficiency Ratio Function of Speed Ratio Curve Name
; !- End-Use Subcategory
OS:Curve:Exponent,
{bba01083-43f5-4ccb-8f1a-458c1d7291fe}, !- Handle
Fan On Off Power Curve, !- Name
1, !- Coefficient1 Constant
0, !- Coefficient2 Constant
0, !- Coefficient3 Constant
0, !- Minimum Value of x {BasedOnField A2}
1; !- Maximum Value of x {BasedOnField A2}
OS:Curve:Cubic,
{142613e7-7f8e-4f5e-987b-f414bfc1d546}, !- Handle
Fan On Off Efficiency Curve, !- Name
1, !- Coefficient1 Constant
0, !- Coefficient2 x
0, !- Coefficient3 x**2
0, !- Coefficient4 x**3
0, !- Minimum Value of x {BasedOnField A2}
1; !- Maximum Value of x {BasedOnField A2}
OS:Coil:Heating:Water,
{cf0eca3e-3f1d-4984-8a48-f141c87d20cf}, !- Handle
Cycling PTAC HW Htg Coil, !- Name
{9f54092d-a4a8-41b8-a381-c4c332ecb843}, !- Availability Schedule Name
, !- U-Factor Times Area Value {W/K}
, !- Maximum Water Flow Rate {m3/s}
, !- Water Inlet Node Name
, !- Water Outlet Node Name
, !- Air Inlet Node Name
, !- Air Outlet Node Name
, !- Performance Input Method
, !- Rated Capacity {W}
, !- Rated Inlet Water Temperature {C}
, !- Rated Inlet Air Temperature {C}
, !- Rated Outlet Water Temperature {C}
, !- Rated Outlet Air Temperature {C}
; !- Rated Ratio for Air and Water Convection
OS:Coil:Cooling:DX:SingleSpeed,
{6cbb9c74-47af-4064-ac48-02c1db36d3ec}, !- Handle
Cycling PTAC 1 Spd DX Clg Coil, !- Name
{9f54092d-a4a8-41b8-a381-c4c332ecb843}, !- Availability Schedule Name
autosize, !- Rated Total Cooling Capacity {W}
autosize, !- Rated Sensible Heat Ratio
3, !- Rated COP {W/W}
autosize, !- Rated Air Flow Rate {m3/s}
773.3, !- Rated Evaporator Fan Power Per Volume Flow Rate {W/(m3/s)}
, !- Air Inlet Node Name
, !- Air Outlet Node Name
{375c013f-f15f-4049-a1bd-7d4735fd5f45}, !- Total Cooling Capacity Function of Temperature Curve Name
{55d14754-fb2d-456e-b587-35c6637eea07}, !- Total Cooling Capacity Function of Flow Fraction Curve Name
{6a283d45-f313-45f4-8663-df4f7af800d7}, !- Energy Input Ratio Function of Temperature Curve Name
{0073a0c9-fad3-4684-b0fd-1c3c6cdbac05}, !- Energy Input Ratio Function of Flow Fraction Curve Name
{4b025358-5550-49ee-bfd6-f69f838f5675}, !- Part Load Fraction Correlation Curve Name
, !- Nominal Time for Condensate Removal to Begin {s}
, !- Ratio of Initial Moisture Evaporation Rate and Steady State Latent Capacity {dimensionless}
, !- Maximum Cycling Rate {cycles/hr}
, !- Latent Capacity Time Constant {s}
, !- Condenser Air Inlet Node Name
AirCooled, !- Condenser Type
0, !- Evaporative Condenser Effectiveness {dimensionless}
Autosize, !- Evaporative Condenser Air Flow Rate {m3/s}
Autosize, !- Evaporative Condenser Pump Rated Power Consumption {W}
0, !- Crankcase Heater Capacity {W}
0, !- Maximum Outdoor Dry-Bulb Temperature for Crankcase Heater Operation {C}
, !- Supply Water Storage Tank Name
, !- Condensate Collection Water Storage Tank Name
0, !- Basin Heater Capacity {W/K}
10, !- Basin Heater Setpoint Temperature {C}
; !- Basin Heater Operating Schedule Name
OS:Curve:Biquadratic,
{375c013f-f15f-4049-a1bd-7d4735fd5f45}, !- Handle
Curve Biquadratic 1, !- Name
0.942587793, !- Coefficient1 Constant
0.009543347, !- Coefficient2 x
0.00068377, !- Coefficient3 x**2
-0.011042676, !- Coefficient4 y
5.249e-006, !- Coefficient5 y**2
-9.72e-006, !- Coefficient6 x*y
17, !- Minimum Value of x {BasedOnField A2}
22, !- Maximum Value of x {BasedOnField A2}
13, !- Minimum Value of y {BasedOnField A3}
46; !- Maximum Value of y {BasedOnField A3}
OS:Curve:Quadratic,
{55d14754-fb2d-456e-b587-35c6637eea07}, !- Handle
Curve Quadratic 1, !- Name
0.8, !- Coefficient1 Constant
0.2, !- Coefficient2 x
0, !- Coefficient3 x**2
0.5, !- Minimum Value of x {BasedOnField A2}
1.5; !- Maximum Value of x {BasedOnField A2}
OS:Curve:Biquadratic,
{6a283d45-f313-45f4-8663-df4f7af800d7}, !- Handle
Curve Biquadratic 2, !- Name
0.342414409, !- Coefficient1 Constant
0.034885008, !- Coefficient2 x
-0.0006237, !- Coefficient3 x**2
0.004977216, !- Coefficient4 y
0.000437951, !- Coefficient5 y**2
-0.000728028, !- Coefficient6 x*y
17, !- Minimum Value of x {BasedOnField A2}
22, !- Maximum Value of x {BasedOnField A2}
13, !- Minimum Value of y {BasedOnField A3}
46; !- Maximum Value of y {BasedOnField A3}
OS:Curve:Quadratic,
{0073a0c9-fad3-4684-b0fd-1c3c6cdbac05}, !- Handle
Curve Quadratic 2, !- Name
1.1552, !- Coefficient1 Constant
-0.1808, !- Coefficient2 x
0.0256, !- Coefficient3 x**2
0.5, !- Minimum Value of x {BasedOnField A2}
1.5; !- Maximum Value of x {BasedOnField A2}
OS:Curve:Quadratic,
{4b025358-5550-49ee-bfd6-f69f838f5675}, !- Handle
Curve Quadratic 3, !- Name
0.85, !- Coefficient1 Constant
0.15, !- Coefficient2 x
0, !- Coefficient3 x**2
0, !- Minimum Value of x {BasedOnField A2}
1; !- Maximum Value of x {BasedOnField A2}
OS:ZoneHVAC:PackagedTerminalAirConditioner,
{85ac1ec0-b6ed-41a3-9de6-ebd31563fa9f}, !- Handle
Cycling PTAC DX Clg HW Htg, !- Name
{9f54092d-a4a8-41b8-a381-c4c332ecb843}, !- Availability Schedule Name
, !- Air Inlet Node Name
, !- Air Outlet Node Name
OutdoorAir:Mixer, !- Outdoor Air Mixer Object Type
, !- Outdoor Air Mixer Name
Autosize, !- Supply Air Flow Rate During Cooling Operation {m3/s}
Autosize, !- Supply Air Flow Rate During Heating Operation {m3/s}
Autosize, !- Supply Air Flow Rate When No Cooling or Heating is Needed {m3/s}
Autosize, !- Outdoor Air Flow Rate During Cooling Operation {m3/s}
Autosize, !- Outdoor Air Flow Rate During Heating Operation {m3/s}
Autosize, !- Outdoor Air Flow Rate When No Cooling or Heating is Needed {m3/s}
{767b3df3-668f-4617-a401-010ddc2aa5b2}, !- Supply Air Fan Name
{cf0eca3e-3f1d-4984-8a48-f141c87d20cf}, !- Heating Coil Name
{6cbb9c74-47af-4064-ac48-02c1db36d3ec}, !- Cooling Coil Name
DrawThrough, !- Fan Placement
{94303a34-b4d5-4c03-b9d7-159d3c6cb998}; !- Supply Air Fan Operating Mode Schedule Name
OS:ScheduleTypeLimits,
{a39d697d-d9d7-4e6a-b699-6d03c9d0c642}, !- Handle
ControlMode, !- Name
0, !- Lower Limit Value {BasedOnField A4}
1, !- Upper Limit Value {BasedOnField A4}
Discrete, !- Numeric Type
ControlMode; !- Unit Type
And here is where it should show up:
