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Revision 9
Keigo's avatar
4k
Keigo
updated 2022-10-12 20:54:52 -0500

Fan:SystemModel power curve does not work

I have two problems.

  • Fan Electric Power of Fan:SystemModel is constant although the fan airflow is variable.
  • Fan:SystemModel is ON when Availability Schedule is 0 during midnight (1am to 6am).

This post is related to my previous question. I have modelled PAU+AHU with AirLoopHVAC:DedicatedOutdoorAirSystem. As you may know, only Fan:SystemModel is allowed for modelling AirLoopHVAC:DedicatedOutdoorAirSystem. Fan:VariableVolume is not allowed. I have modelled PAU with DCV by CO2 concentration, so the outdoor airflow rate is variable, but Fan Electric Power is constant. I don't know why. Besides, Availability Schedule makes the outdoor airflow rate 0 during midnight of weekdays, but the fan consumes electric power for 24 hours. Please find the charts below.

image description

image description

My Fan:SystemModel input is as follows. Is there anything wrong with it?

Fan:SystemModel,
    PAU_Tower12_Office_1 Supply Fan,  !- Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Cooling Coil Outlet,  !- Air Inlet Node Name
    PAU_Tower12_Office_1 Supply Fan Outlet,  !- Air Outlet Node Name
    autosize,                !- Design Maximum Air Flow Rate {m3/s}
    Continuous,              !- Speed Control Method
    0.2,                     !- Electric Power Minimum Flow Rate Fraction
    1200,                    !- Design Pressure Rise {Pa}
    0.9,                     !- Motor Efficiency
    1,                       !- Motor In Air Stream Fraction
    autosize,                !- Design Electric Power Consumption {W}
    TotalEfficiencyAndPressure,  !- Design Power Sizing Method
    ,                        !- Electric Power Per Unit Flow Rate {W/(m3/s)}
    ,                        !- Electric Power Per Unit Flow Rate Per Unit Pressure {W/((m3/s)-Pa)}
    0.7,                     !- Fan Total Efficiency
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Electric Power Function of Flow Fraction Curve Name
    ,                        !- Night Ventilation Mode Pressure Rise {Pa}
    ,                        !- Night Ventilation Mode Flow Fraction
    ,                        !- Motor Loss Zone Name
    ,                        !- Motor Loss Radiative Fraction
    General;                 !- End-Use Subcategory
    ,                        !- Number of Speeds
    ,                        !- Speed 1 Flow Fraction
    ,                        !- Speed 1 Electric Power Fraction

Fan curve input is as follows. It is based on ASHRAE90.1 TABLE G3.1.3.15. I think there should be no problem with it becuase AHUs that have been modelled with Fan:Variable and with the same coeciffients as this fan power curve have variable Fan Electric Power.

Curve:Cubic,
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Name
    0.0013,                  !- Coefficient1 Constant
    0.147,                   !- Coefficient2 x
    0.9506,                  !- Coefficient3 x**2
    -0.0998,                 !- Coefficient4 x**3
    0,                       !- Minimum Value of x
    1;                       !- Maximum Value of x

AirLoopHVAC:DedicatedOutdoorAirSystem and Fan:SystemModel use the same Availability Schedule, so Fan:SystemModel should be OFF during midnight, but it isn't.

AirLoopHVAC:DedicatedOutdoorAirSystem,
    PAU_Tower12_Office_1,    !- Name
    PAU_Tower12_Office_1 OA System,  !- AirLoopHVAC:OutdoorAirSystem Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Zone Mixer,  !- AirLoopHVAC:Mixer Name
    PAU_Tower12_Office_1 Zone Splitter,  !- AirLoopHVAC:Splitter Name
    4.5,                     !- Preheat Design Temperature {C}
    0.004,                   !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
    17.5,                    !- Precool Design Temperature {C}
    0.012,                   !- Precool Design Humidity Ratio {kgWater/kgDryAir}
    5,                       !- Number of AirLoopHVAC
    VAV_TOWER12_28F,         !- AirLoopHVAC 1 Name
    VAV_TOWER12_26-27F,      !- AirLoopHVAC 2 Name
    VAV_TOWER12_25F,         !- AirLoopHVAC 3 Name
    VAV_TOWER12_23-24F,      !- AirLoopHVAC 4 Name
    VAV_TOWER12_22F;         !- AirLoopHVAC 5 Name

P.S.

I noticed another problem of AirLoopHVAC:DedicatedOutdoorAirSystem. Please let me know If I should post as a separate question.

It's not about fan, but about coil of PAU. I updated the idf file from v9-2-0 to v9-6-0, but I got severe error about coil sizing of PAU, and the calculation terminated. All the parameters (flow rate, temperature and humidity ratio) of the coil was autosize, which caused the error. The error disappeared when I hardsized them. When I ran the idf file v9-2-0, I haven't got the error, but I noticed that the coil was not autosized correctly. Inlet Air Temperature was -999°C, and Coil Load was 0W as shown below.

image description

How can the coil for AirLoopHVAC:DedicatedOutdoorAirSystem be autosized? AirLoopHVAC:DedicatedOutdoorAirSystem is not listed in Sizing:Zone, Sizing:System or Sizing:Plant, so there is no class that has necessary information to autosize coil.

About fan flow rate, it's ok because it can be autosized by summing each zone outdoor flow rate.

Revision 8
Keigo's avatar
4k
Keigo
updated 2022-03-29 08:40:50 -0500

Fan:SystemModel power curve does not work

I have two problems.

  • Fan Electric Power of Fan:SystemModel is constant although the fan airflow is variable.
  • Fan:SystemModel is ON when Availability Schedule is 0 during midnight (1am to 6am).

This post is related to my previous question. I have modelled PAU+AHU with AirLoopHVAC:DedicatedOutdoorAirSystem. As you may know, only Fan:SystemModel is allowed for modelling AirLoopHVAC:DedicatedOutdoorAirSystem. Fan:VariableVolume is not allowed. I have modelled PAU with DCV by CO2 concentration, so the outdoor airflow rate is variable, but Fan Electric Power is constant. I don't know why. Besides, Availability Schedule makes the outdoor airflow rate 0 during midnight of weekdays, but the fan consumes electric power for 24 hours. Please find the charts below.

image description

image description

My Fan:SystemModel input is as follows. Is there anything wrong with it?

Fan:SystemModel,
    PAU_Tower12_Office_1 Supply Fan,  !- Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Cooling Coil Outlet,  !- Air Inlet Node Name
    PAU_Tower12_Office_1 Supply Fan Outlet,  !- Air Outlet Node Name
    autosize,                !- Design Maximum Air Flow Rate {m3/s}
    Continuous,              !- Speed Control Method
    0.2,                     !- Electric Power Minimum Flow Rate Fraction
    1200,                    !- Design Pressure Rise {Pa}
    0.9,                     !- Motor Efficiency
    1,                       !- Motor In Air Stream Fraction
    autosize,                !- Design Electric Power Consumption {W}
    TotalEfficiencyAndPressure,  !- Design Power Sizing Method
    ,                        !- Electric Power Per Unit Flow Rate {W/(m3/s)}
    ,                        !- Electric Power Per Unit Flow Rate Per Unit Pressure {W/((m3/s)-Pa)}
    0.7,                     !- Fan Total Efficiency
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Electric Power Function of Flow Fraction Curve Name
    ,                        !- Night Ventilation Mode Pressure Rise {Pa}
    ,                        !- Night Ventilation Mode Flow Fraction
    ,                        !- Motor Loss Zone Name
    ,                        !- Motor Loss Radiative Fraction
    General;                 !- End-Use Subcategory
    ,                        !- Number of Speeds
    ,                        !- Speed 1 Flow Fraction
    ,                        !- Speed 1 Electric Power Fraction

Fan curve input is as follows. It is based on ASHRAE90.1 TABLE G3.1.3.15. I think there should be no problem with it becuase AHUs that have been modelled with Fan:Variable and with the same coeciffients as this fan power curve have variable Fan Electric Power.

Curve:Cubic,
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Name
    0.0013,                  !- Coefficient1 Constant
    0.147,                   !- Coefficient2 x
    0.9506,                  !- Coefficient3 x**2
    -0.0998,                 !- Coefficient4 x**3
    0,                       !- Minimum Value of x
    1;                       !- Maximum Value of x

AirLoopHVAC:DedicatedOutdoorAirSystem and Fan:SystemModel use the same Availability Schedule, so Fan:SystemModel should be OFF during midnight, but it isn't.

AirLoopHVAC:DedicatedOutdoorAirSystem,
    PAU_Tower12_Office_1,    !- Name
    PAU_Tower12_Office_1 OA System,  !- AirLoopHVAC:OutdoorAirSystem Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Zone Mixer,  !- AirLoopHVAC:Mixer Name
    PAU_Tower12_Office_1 Zone Splitter,  !- AirLoopHVAC:Splitter Name
    4.5,                     !- Preheat Design Temperature {C}
    0.004,                   !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
    17.5,                    !- Precool Design Temperature {C}
    0.012,                   !- Precool Design Humidity Ratio {kgWater/kgDryAir}
    5,                       !- Number of AirLoopHVAC
    VAV_TOWER12_28F,         !- AirLoopHVAC 1 Name
    VAV_TOWER12_26-27F,      !- AirLoopHVAC 2 Name
    VAV_TOWER12_25F,         !- AirLoopHVAC 3 Name
    VAV_TOWER12_23-24F,      !- AirLoopHVAC 4 Name
    VAV_TOWER12_22F;         !- AirLoopHVAC 5 Name

P.S.

I noticed another problem of AirLoopHVAC:DedicatedOutdoorAirSystem. Please let me know If I should post as a separate question.

It's not about fan, but about coil of PAU. I updated the idf file from v9-2-0 to v9-6-0, but I got severe error about coil sizing of PAU, and the calculation terminated. All the parameters (flow rate, temperature and humidity ratio) of the coil was autosize, which caused the error. The error disappeared when I hardsized them. When I ran the idf file v9-2-0, I haven't got the error, but I noticed that the coil was not autosized correctly. Inlet Air Temperature was -999°C, and Coil Load was 0W as shown below.

image description

How can the coil for AirLoopHVAC:DedicatedOutdoorAirSystem be autosized? AirLoopHVAC:DedicatedOutdoorAirSystem is not listed in Sizing:Zone, Sizing:System or Sizing:Plant, so there is no class that has necessary information to autosize coil.

About fan flow rate, it's ok because it can be autosized by summing each zone outdoor flow rate.

Revision 7
Keigo's avatar
4k
Keigo
updated 2022-03-06 11:50:24 -0500

Fan:SystemModel power curve does not work

I have two problems.

  • Fan Electric Power of Fan:SystemModel is constant although the fan airflow is variable.
  • Fan:SystemModel is ON when Availability Schedule is 0 during midnight (1am to 6am).

This post is related to my previous question. I have modelled PAU+AHU with AirLoopHVAC:DedicatedOutdoorAirSystem. As you may know, only Fan:SystemModel is allowed for modelling AirLoopHVAC:DedicatedOutdoorAirSystem. Fan:VariableVolume is not allowed. I have modelled PAU with DCV by CO2 concentration, so the outdoor airflow rate is variable, but Fan Electric Power is constant. I don't know why. Besides, Availability Schedule makes the outdoor airflow rate 0 during midnight of weekdays, but the fan consumes electric power for 24 hours. Please find the charts below.

image descriptionimage description

image description

My Fan:SystemModel input is as follows. Is there anything wrong with it?

Fan:SystemModel,
    PAU_Tower12_Office_1 Supply Fan,  !- Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Cooling Coil Outlet,  !- Air Inlet Node Name
    PAU_Tower12_Office_1 Supply Fan Outlet,  !- Air Outlet Node Name
    autosize,                !- Design Maximum Air Flow Rate {m3/s}
    Continuous,              !- Speed Control Method
    0.2,                     !- Electric Power Minimum Flow Rate Fraction
    1200,                    !- Design Pressure Rise {Pa}
    0.9,                     !- Motor Efficiency
    1,                       !- Motor In Air Stream Fraction
    autosize,                !- Design Electric Power Consumption {W}
    TotalEfficiencyAndPressure,  !- Design Power Sizing Method
    ,                        !- Electric Power Per Unit Flow Rate {W/(m3/s)}
    ,                        !- Electric Power Per Unit Flow Rate Per Unit Pressure {W/((m3/s)-Pa)}
    0.7,                     !- Fan Total Efficiency
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Electric Power Function of Flow Fraction Curve Name
    ,                        !- Night Ventilation Mode Pressure Rise {Pa}
    ,                        !- Night Ventilation Mode Flow Fraction
    ,                        !- Motor Loss Zone Name
    ,                        !- Motor Loss Radiative Fraction
    General;                 !- End-Use Subcategory
    ,                        !- Number of Speeds
    ,                        !- Speed 1 Flow Fraction
    ,                        !- Speed 1 Electric Power Fraction

Fan curve input is as follows. It is based on ASHRAE90.1 TABLE G3.1.3.15. I think there should be no problem with it becuase AHUs that have been modelled with Fan:Variable and with the same coeciffients as this fan power curve have variable Fan Electric Power.

Curve:Cubic,
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Name
    0.0013,                  !- Coefficient1 Constant
    0.147,                   !- Coefficient2 x
    0.9506,                  !- Coefficient3 x**2
    -0.0998,                 !- Coefficient4 x**3
    0,                       !- Minimum Value of x
    1;                       !- Maximum Value of x

AirLoopHVAC:DedicatedOutdoorAirSystem and Fan:SystemModel use the same Availability Schedule, so Fan:SystemModel should be OFF during midnight, but it isn't.

AirLoopHVAC:DedicatedOutdoorAirSystem,
    PAU_Tower12_Office_1,    !- Name
    PAU_Tower12_Office_1 OA System,  !- AirLoopHVAC:OutdoorAirSystem Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Zone Mixer,  !- AirLoopHVAC:Mixer Name
    PAU_Tower12_Office_1 Zone Splitter,  !- AirLoopHVAC:Splitter Name
    4.5,                     !- Preheat Design Temperature {C}
    0.004,                   !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
    17.5,                    !- Precool Design Temperature {C}
    0.012,                   !- Precool Design Humidity Ratio {kgWater/kgDryAir}
    5,                       !- Number of AirLoopHVAC
    VAV_TOWER12_28F,         !- AirLoopHVAC 1 Name
    VAV_TOWER12_26-27F,      !- AirLoopHVAC 2 Name
    VAV_TOWER12_25F,         !- AirLoopHVAC 3 Name
    VAV_TOWER12_23-24F,      !- AirLoopHVAC 4 Name
    VAV_TOWER12_22F;         !- AirLoopHVAC 5 Name

P.S.

I noticed another problem of AirLoopHVAC:DedicatedOutdoorAirSystem. Please let me know If I should post as a separate question.

It's not about fan, but about coil of PAU. I updated the idf file from v9-2-0 to v9-6-0, but I got severe error about coil sizing of PAU, and the calculation terminated. All the parameters (flow rate, temperature and humidity ratio) of the coil was autosize, which caused the error. The error disappeared when I hardsized them. When I ran the idf file v9-2-0, I haven't got the error, but I noticed that the coil was not autosized correctly. Inlet Air Temperature was -999°C, and Coil Load was 0W as shown below.

image description

How can the coil for AirLoopHVAC:DedicatedOutdoorAirSystem be autosized? AirLoopHVAC:DedicatedOutdoorAirSystem is not listed in Sizing:Zone, Sizing:System or Sizing:Plant, so there is no class that has necessary information to autosize coil.

About fan flow rate, it's ok because it can be autosized by summing each zone outdoor flow rate.

Revision 6
Aaron Boranian's avatar
14.1k
Aaron Boranian
updated 2022-03-04 09:06:59 -0500

Fan:SystemModel power curve does not work

I have two problems.

  • Fan Electric Power of Fan:SystemModel is constant although the fan airflow is variable.
  • Fan:SystemModel is ON when Availability Schedule is 0 during midnight (1am to 6am).

This post is related to my previous question. I have modelled PAU+AHU with AirLoopHVAC:DedicatedOutdoorAirSystem. As you may know, only Fan:SystemModel is allowed for modelling AirLoopHVAC:DedicatedOutdoorAirSystem. Fan:VariableVolume is not allowed. I have modelled PAU with DCV by CO2 concentration, so the outdoor airflow rate is variable, but Fan Electric Power is constant. I don't know why. Besides, Availability Schedule makes the outdoor airflow rate 0 during midnight of weekdays, but the fan consumes electric power for 24 hours. Please find the charts below.

image description

image description

My Fan:SystemModel input is as follows. Is there anything wrong with it?

Fan:SystemModel,
    PAU_Tower12_Office_1 Supply Fan,  !- Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Cooling Coil Outlet,  !- Air Inlet Node Name
    PAU_Tower12_Office_1 Supply Fan Outlet,  !- Air Outlet Node Name
    autosize,                !- Design Maximum Air Flow Rate {m3/s}
    Continuous,              !- Speed Control Method
    0.2,                     !- Electric Power Minimum Flow Rate Fraction
    1200,                    !- Design Pressure Rise {Pa}
    0.9,                     !- Motor Efficiency
    1,                       !- Motor In Air Stream Fraction
    autosize,                !- Design Electric Power Consumption {W}
    TotalEfficiencyAndPressure,  !- Design Power Sizing Method
    ,                        !- Electric Power Per Unit Flow Rate {W/(m3/s)}
    ,                        !- Electric Power Per Unit Flow Rate Per Unit Pressure {W/((m3/s)-Pa)}
    0.7,                     !- Fan Total Efficiency
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Electric Power Function of Flow Fraction Curve Name
    ,                        !- Night Ventilation Mode Pressure Rise {Pa}
    ,                        !- Night Ventilation Mode Flow Fraction
    ,                        !- Motor Loss Zone Name
    ,                        !- Motor Loss Radiative Fraction
    General;                 !- End-Use Subcategory
    ,                        !- Number of Speeds
    ,                        !- Speed 1 Flow Fraction
    ,                        !- Speed 1 Electric Power Fraction

Fan curve input is as follows. It is based on ASHRAE90.1 TABLE G3.1.3.15. I think there should be no problem with it becuase AHUs that have been modelled with Fan:Variable and with the same coeciffients as this fan power curve have variable Fan Electric Power.

Curve:Cubic,
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Name
    0.0013,                  !- Coefficient1 Constant
    0.147,                   !- Coefficient2 x
    0.9506,                  !- Coefficient3 x**2
    -0.0998,                 !- Coefficient4 x**3
    0,                       !- Minimum Value of x
    1;                       !- Maximum Value of x

AirLoopHVAC:DedicatedOutdoorAirSystem and Fan:SystemModel use the same Availability Schedule, so Fan:SystemModel should be OFF during midnight, but it isn't.

AirLoopHVAC:DedicatedOutdoorAirSystem,
    PAU_Tower12_Office_1,    !- Name
    PAU_Tower12_Office_1 OA System,  !- AirLoopHVAC:OutdoorAirSystem Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Zone Mixer,  !- AirLoopHVAC:Mixer Name
    PAU_Tower12_Office_1 Zone Splitter,  !- AirLoopHVAC:Splitter Name
    4.5,                     !- Preheat Design Temperature {C}
    0.004,                   !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
    17.5,                    !- Precool Design Temperature {C}
    0.012,                   !- Precool Design Humidity Ratio {kgWater/kgDryAir}
    5,                       !- Number of AirLoopHVAC
    VAV_TOWER12_28F,         !- AirLoopHVAC 1 Name
    VAV_TOWER12_26-27F,      !- AirLoopHVAC 2 Name
    VAV_TOWER12_25F,         !- AirLoopHVAC 3 Name
    VAV_TOWER12_23-24F,      !- AirLoopHVAC 4 Name
    VAV_TOWER12_22F;         !- AirLoopHVAC 5 Name

P.S.

I noticed another problem of AirLoopHVAC:DedicatedOutdoorAirSystem. Please let me know If I should post as a separate question.

It's not about fan, but about coil of PAU. I updated the idf file from v9-2-0 to v9-6-0, but I got severe error about coil sizing of PAU, and the calculation terminated. All the parameters (flow rate, temperature and humidity ratio) of the coil was autosize, which caused the error. The error disappeared when I hardsized them. When I ran the idf file v9-2-0, I haven't got the error, but I noticed that the coil was not autosized correctly. Inlet Air Temperature was -999°C, and Coil Load was 0W as shown below.

image description

How can the coil for AirLoopHVAC:DedicatedOutdoorAirSystem be autosized? AirLoopHVAC:DedicatedOutdoorAirSystem is not listed in Sizing:Zone, Sizing:System or Sizing:Plant, so there is no class that has necessary information to autosize coil.

About fan flow rate, it's ok because it can be autosized by summing each zone outdoor flow rate.

Revision 5
Keigo's avatar
4k
Keigo
updated 2022-03-04 08:29:49 -0500

Fan:SystemModel power curve does not work

I have two problems.

  • Fan Electric Power of Fan:SystemModel is constant although the fan airflow is variable.
  • Fan:SystemModel is ON when Availability Schedule is 0 during midnight (1am to 6am).

This post is related to my previous question. I have modelled PAU+AHU with AirLoopHVAC:DedicatedOutdoorAirSystem. As you may know, only Fan:SystemModel is allowed for modelling AirLoopHVAC:DedicatedOutdoorAirSystem. Fan:VariableVolume is not allowed. I have modelled PAU with DCV by CO2 concentration, so the outdoor airflow rate is variable, but Fan Electric Power is constant. I don't know why. Besides, Availability Schedule makes the outdoor airflow rate 0 during midnight of weekdays, but the fan consumes electric power for 24 hours. Please find the charts below.

image description

image description

My Fan:SystemModel input is as follows. Is there anything wrong with it?

Fan:SystemModel,
    PAU_Tower12_Office_1 Supply Fan,  !- Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Cooling Coil Outlet,  !- Air Inlet Node Name
    PAU_Tower12_Office_1 Supply Fan Outlet,  !- Air Outlet Node Name
    autosize,                !- Design Maximum Air Flow Rate {m3/s}
    Continuous,              !- Speed Control Method
    0.2,                     !- Electric Power Minimum Flow Rate Fraction
    1200,                    !- Design Pressure Rise {Pa}
    0.9,                     !- Motor Efficiency
    1,                       !- Motor In Air Stream Fraction
    autosize,                !- Design Electric Power Consumption {W}
    TotalEfficiencyAndPressure,  !- Design Power Sizing Method
    ,                        !- Electric Power Per Unit Flow Rate {W/(m3/s)}
    ,                        !- Electric Power Per Unit Flow Rate Per Unit Pressure {W/((m3/s)-Pa)}
    0.7,                     !- Fan Total Efficiency
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Electric Power Function of Flow Fraction Curve Name
    ,                        !- Night Ventilation Mode Pressure Rise {Pa}
    ,                        !- Night Ventilation Mode Flow Fraction
    ,                        !- Motor Loss Zone Name
    ,                        !- Motor Loss Radiative Fraction
    General;                 !- End-Use Subcategory
    ,                        !- Number of Speeds
    ,                        !- Speed 1 Flow Fraction
    ,                        !- Speed 1 Electric Power Fraction

Fan curve input is as follows. It is based on ASHRAE90.1 TABLE G3.1.3.15. I think there should be no problem with it becuase AHUs that have been modelled with Fan:Variable and with the same coeciffients as this fan power curve have variable Fan Electric Power.

Curve:Cubic,
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Name
    0.0013,                  !- Coefficient1 Constant
    0.147,                   !- Coefficient2 x
    0.9506,                  !- Coefficient3 x**2
    -0.0998,                 !- Coefficient4 x**3
    0,                       !- Minimum Value of x
    1;                       !- Maximum Value of x

AirLoopHVAC:DedicatedOutdoorAirSystem and Fan:SystemModel use the same Availability Schedule, so Fan:SystemModel should be OFF during midnight, but it isn't.

AirLoopHVAC:DedicatedOutdoorAirSystem,
    PAU_Tower12_Office_1,    !- Name
    PAU_Tower12_Office_1 OA System,  !- AirLoopHVAC:OutdoorAirSystem Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Zone Mixer,  !- AirLoopHVAC:Mixer Name
    PAU_Tower12_Office_1 Zone Splitter,  !- AirLoopHVAC:Splitter Name
    4.5,                     !- Preheat Design Temperature {C}
    0.004,                   !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
    17.5,                    !- Precool Design Temperature {C}
    0.012,                   !- Precool Design Humidity Ratio {kgWater/kgDryAir}
    5,                       !- Number of AirLoopHVAC
    VAV_TOWER12_28F,         !- AirLoopHVAC 1 Name
    VAV_TOWER12_26-27F,      !- AirLoopHVAC 2 Name
    VAV_TOWER12_25F,         !- AirLoopHVAC 3 Name
    VAV_TOWER12_23-24F,      !- AirLoopHVAC 4 Name
    VAV_TOWER12_22F;         !- AirLoopHVAC 5 Name
Revision 4
Keigo's avatar
4k
Keigo
updated 2022-03-04 08:20:33 -0500

Fan:SystemModel power curve does not work

I have two problems.

  • Fan Electric Power of Fan:SystemModel is constant although the fan airflow is variable.
  • Fan:SystemModel is ON when Availability Schedule is 0 during midnight (1am to 6am).

This post is related to my previous question. I have modelled PAU+AHU with AirLoopHVAC:DedicatedOutdoorAirSystem. As you may know, only Fan:SystemModel is allowed for modelling AirLoopHVAC:DedicatedOutdoorAirSystem. Fan:VariableVolume is not allowed. I have modelled PAU with DCV by CO2 concentration, so the outdoor airflow rate is variable, but Fan Electric Power is constant. I don't know why. Besides, Availability Schedule makes the outdoor airflow rate 0 during midnight of weekdays, but the fan consumes electric power for 24 hours. Please find the charts below.

image description

image descriptionimage description

My Fan:SystemModel input is as follows. Is there anything wrong with it?

Fan:SystemModel,
    PAU_Tower12_Office_1 Supply Fan,  !- Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Cooling Coil Outlet,  !- Air Inlet Node Name
    PAU_Tower12_Office_1 Supply Fan Outlet,  !- Air Outlet Node Name
    autosize,                !- Design Maximum Air Flow Rate {m3/s}
    Continuous,              !- Speed Control Method
    0.2,                     !- Electric Power Minimum Flow Rate Fraction
    1200,                    !- Design Pressure Rise {Pa}
    0.9,                     !- Motor Efficiency
    1,                       !- Motor In Air Stream Fraction
    autosize,                !- Design Electric Power Consumption {W}
    TotalEfficiencyAndPressure,  !- Design Power Sizing Method
    ,                        !- Electric Power Per Unit Flow Rate {W/(m3/s)}
    ,                        !- Electric Power Per Unit Flow Rate Per Unit Pressure {W/((m3/s)-Pa)}
    0.7,                     !- Fan Total Efficiency
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Electric Power Function of Flow Fraction Curve Name
    ,                        !- Night Ventilation Mode Pressure Rise {Pa}
    ,                        !- Night Ventilation Mode Flow Fraction
    ,                        !- Motor Loss Zone Name
    ,                        !- Motor Loss Radiative Fraction
    General;                 !- End-Use Subcategory
    ,                        !- Number of Speeds
    ,                        !- Speed 1 Flow Fraction
    ,                        !- Speed 1 Electric Power Fraction

Fan curve input is as follows. It is based on ASHRAE90.1 TABLE G3.1.3.15. I think there should be no problem with it becuase AHUs that have been modelled with Fan:Variable and with the same coeciffients as this fan power curve have variable Fan Electric Power.

Curve:Cubic,
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Name
    0.0013,                  !- Coefficient1 Constant
    0.147,                   !- Coefficient2 x
    0.9506,                  !- Coefficient3 x**2
    -0.0998,                 !- Coefficient4 x**3
    0,                       !- Minimum Value of x
    1;                       !- Maximum Value of x

AirLoopHVAC:DedicatedOutdoorAirSystem and Fan:SystemModel use the same Availability Schedule, so Fan:SystemModel should be OFF during midnight, but it isn't.

AirLoopHVAC:DedicatedOutdoorAirSystem,
    PAU_Tower12_Office_1,    !- Name
    PAU_Tower12_Office_1 OA System,  !- AirLoopHVAC:OutdoorAirSystem Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Zone Mixer,  !- AirLoopHVAC:Mixer Name
    PAU_Tower12_Office_1 Zone Splitter,  !- AirLoopHVAC:Splitter Name
    4.5,                     !- Preheat Design Temperature {C}
    0.004,                   !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
    17.5,                    !- Precool Design Temperature {C}
    0.012,                   !- Precool Design Humidity Ratio {kgWater/kgDryAir}
    5,                       !- Number of AirLoopHVAC
    VAV_TOWER12_28F,         !- AirLoopHVAC 1 Name
    VAV_TOWER12_26-27F,      !- AirLoopHVAC 2 Name
    VAV_TOWER12_25F,         !- AirLoopHVAC 3 Name
    VAV_TOWER12_23-24F,      !- AirLoopHVAC 4 Name
    VAV_TOWER12_22F;         !- AirLoopHVAC 5 Name
Revision 3
Keigo's avatar
4k
Keigo
updated 2022-03-04 08:08:24 -0500

Fan:SystemModel power curve does not work

I have two problems.

  • Fan Electric Power of Fan:SystemModel is constant although the fan airflow is variable.
  • Fan:SystemModel is ON when Availability Schedule is 0 during midnight (1am to 6am).

This post is related to my previous question. I have modelled PAU+AHU with AirLoopHVAC:DedicatedOutdoorAirSystem. As you may know, only Fan:SystemModel is allowed for modelling AirLoopHVAC:DedicatedOutdoorAirSystem. Fan:VariableVolume is not allowed. I have modelled PAU with DCV by CO2 concentration, so the outdoor airflow rate is variable, but Fan Electric Power is constant. I don't know why. Besides, Availability Schedule makes the outdoor airflow rate 0 during midnight of weekdays, but the fan consumes electric power for 24 hours. Please find the charts below.

image description

image descriptionimage description

My Fan:SystemModel input is as follows. Is there anything wrong with it?

Fan:SystemModel,
    PAU_Tower12_Office_1 Supply Fan,  !- Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Cooling Coil Outlet,  !- Air Inlet Node Name
    PAU_Tower12_Office_1 Supply Fan Outlet,  !- Air Outlet Node Name
    autosize,                !- Design Maximum Air Flow Rate {m3/s}
    Continuous,              !- Speed Control Method
    0.2,                     !- Electric Power Minimum Flow Rate Fraction
    1200,                    !- Design Pressure Rise {Pa}
    0.9,                     !- Motor Efficiency
    1,                       !- Motor In Air Stream Fraction
    autosize,                !- Design Electric Power Consumption {W}
    TotalEfficiencyAndPressure,  !- Design Power Sizing Method
    ,                        !- Electric Power Per Unit Flow Rate {W/(m3/s)}
    ,                        !- Electric Power Per Unit Flow Rate Per Unit Pressure {W/((m3/s)-Pa)}
    0.7,                     !- Fan Total Efficiency
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Electric Power Function of Flow Fraction Curve Name
    ,                        !- Night Ventilation Mode Pressure Rise {Pa}
    ,                        !- Night Ventilation Mode Flow Fraction
    ,                        !- Motor Loss Zone Name
    ,                        !- Motor Loss Radiative Fraction
    General;                 !- End-Use Subcategory
    ,                        !- Number of Speeds
    ,                        !- Speed 1 Flow Fraction
    ,                        !- Speed 1 Electric Power Fraction

Fan curve input is as follows. It is based on ASHRAE90.1 TABLE G3.1.3.15. I think there should be no problem with it becuase AHUs that have been modelled with Fan:Variable and with the same coeciffients as this fan power curve have variable Fan Electric Power.

Curve:Cubic,
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Name
    0.0013,                  !- Coefficient1 Constant
    0.147,                   !- Coefficient2 x
    0.9506,                  !- Coefficient3 x**2
    -0.0998,                 !- Coefficient4 x**3
    0,                       !- Minimum Value of x
    1;                       !- Maximum Value of x

AirLoopHVAC:DedicatedOutdoorAirSystem and Fan:SystemModel use the same Availability Schedule, so Fan:SystemModel should be OFF during midnight, but it isn't.

AirLoopHVAC:DedicatedOutdoorAirSystem,
    PAU_Tower12_Office_1,    !- Name
    PAU_Tower12_Office_1 OA System,  !- AirLoopHVAC:OutdoorAirSystem Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Zone Mixer,  !- AirLoopHVAC:Mixer Name
    PAU_Tower12_Office_1 Zone Splitter,  !- AirLoopHVAC:Splitter Name
    4.5,                     !- Preheat Design Temperature {C}
    0.004,                   !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
    17.5,                    !- Precool Design Temperature {C}
    0.012,                   !- Precool Design Humidity Ratio {kgWater/kgDryAir}
    5,                       !- Number of AirLoopHVAC
    VAV_TOWER12_28F,         !- AirLoopHVAC 1 Name
    VAV_TOWER12_26-27F,      !- AirLoopHVAC 2 Name
    VAV_TOWER12_25F,         !- AirLoopHVAC 3 Name
    VAV_TOWER12_23-24F,      !- AirLoopHVAC 4 Name
    VAV_TOWER12_22F;         !- AirLoopHVAC 5 Name
Revision 2
Keigo's avatar
4k
Keigo
updated 2022-03-04 07:57:35 -0500

Fan:SystemModel power curve does not work

I have two problems.

  • Fan Electric Power of Fan:SystemModel is constant although the fan airflow is variable.
  • Fan:SystemModel is ON when Availability Schedule is 0 during midnight (1am to 6am).

This post is related to my previous question. I have modelled PAU+AHU with AirLoopHVAC:DedicatedOutdoorAirSystem. As you may know, only Fan:SystemModel is allowed for modelling AirLoopHVAC:DedicatedOutdoorAirSystem. Fan:VariableVolume is not allowed. I have modelled PAU with DCV by CO2 concentration, so the outdoor airflow rate is variable, but Fan Electric Power is constant. I don't know why. Besides, Availability Schedule makes the outdoor airflow rate 0 during midnight of weekdays, but the fan consumes electric power for 24 hours. Please find the charts below.

image descriptionimage description

image description

My Fan:SystemModel input is as follows. Is there anything wrong with it?

Fan:SystemModel,
    PAU_Tower12_Office_1 Supply Fan,  !- Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Cooling Coil Outlet,  !- Air Inlet Node Name
    PAU_Tower12_Office_1 Supply Fan Outlet,  !- Air Outlet Node Name
    autosize,                !- Design Maximum Air Flow Rate {m3/s}
    Continuous,              !- Speed Control Method
    0.2,                     !- Electric Power Minimum Flow Rate Fraction
    1200,                    !- Design Pressure Rise {Pa}
    0.9,                     !- Motor Efficiency
    1,                       !- Motor In Air Stream Fraction
    autosize,                !- Design Electric Power Consumption {W}
    TotalEfficiencyAndPressure,  !- Design Power Sizing Method
    ,                        !- Electric Power Per Unit Flow Rate {W/(m3/s)}
    ,                        !- Electric Power Per Unit Flow Rate Per Unit Pressure {W/((m3/s)-Pa)}
    0.7,                     !- Fan Total Efficiency
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Electric Power Function of Flow Fraction Curve Name
    ,                        !- Night Ventilation Mode Pressure Rise {Pa}
    ,                        !- Night Ventilation Mode Flow Fraction
    ,                        !- Motor Loss Zone Name
    ,                        !- Motor Loss Radiative Fraction
    General;                 !- End-Use Subcategory
    ,                        !- Number of Speeds
    ,                        !- Speed 1 Flow Fraction
    ,                        !- Speed 1 Electric Power Fraction

Fan curve input is as follows. It is based on ASHRAE90.1 TABLE G3.1.3.15. I think there should be no problem with it becuase AHUs that have been modelled with Fan:Variable and with the same coeciffients as this fan power curve have variable Fan Electric Power.

Curve:Cubic,
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Name
    0.0013,                  !- Coefficient1 Constant
    0.147,                   !- Coefficient2 x
    0.9506,                  !- Coefficient3 x**2
    -0.0998,                 !- Coefficient4 x**3
    0,                       !- Minimum Value of x
    1;                       !- Maximum Value of x

AirLoopHVAC:DedicatedOutdoorAirSystem and Fan:SystemModel use the same Availability Schedule, so Fan:SystemModel should be OFF during midnight, but it isn't.

AirLoopHVAC:DedicatedOutdoorAirSystem,
    PAU_Tower12_Office_1,    !- Name
    PAU_Tower12_Office_1 OA System,  !- AirLoopHVAC:OutdoorAirSystem Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Zone Mixer,  !- AirLoopHVAC:Mixer Name
    PAU_Tower12_Office_1 Zone Splitter,  !- AirLoopHVAC:Splitter Name
    4.5,                     !- Preheat Design Temperature {C}
    0.004,                   !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
    17.5,                    !- Precool Design Temperature {C}
    0.012,                   !- Precool Design Humidity Ratio {kgWater/kgDryAir}
    5,                       !- Number of AirLoopHVAC
    VAV_TOWER12_28F,         !- AirLoopHVAC 1 Name
    VAV_TOWER12_26-27F,      !- AirLoopHVAC 2 Name
    VAV_TOWER12_25F,         !- AirLoopHVAC 3 Name
    VAV_TOWER12_23-24F,      !- AirLoopHVAC 4 Name
    VAV_TOWER12_22F;         !- AirLoopHVAC 5 Name
Revision 1
Keigo's avatar
4k
Keigo
asked 2022-03-04 07:46:49 -0500

Fan:SystemModel power curve does not work

I have two problems.

  • Fan Electric Power of Fan:SystemModel is constant although the fan airflow is variable.
  • Fan:SystemModel is ON when Availability Schedule is 0 during midnight (1am to 6am). midnight.

This post is related to my previous question. I have modelled PAU+AHU with AirLoopHVAC:DedicatedOutdoorAirSystem. As you may know, only Fan:SystemModel is allowed for modelling AirLoopHVAC:DedicatedOutdoorAirSystem. Fan:VariableVolume is not allowed. I have modelled PAU with DCV by CO2 concentration, so the outdoor airflow rate is variable, but Fan Electric Power is constant. I don't know why. Besides, Availability Schedule makes the outdoor airflow rate 0 during midnight of weekdays, but the fan consumes electric power for 24 hours. Please find the charts below.

image description

image description

My Fan:SystemModel input is as follows. Is there anything wrong with it?

Fan:SystemModel,
    PAU_Tower12_Office_1 Supply Fan,  !- Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Cooling Coil Outlet,  !- Air Inlet Node Name
    PAU_Tower12_Office_1 Supply Fan Outlet,  !- Air Outlet Node Name
    autosize,                !- Design Maximum Air Flow Rate {m3/s}
    Continuous,              !- Speed Control Method
    0.2,                     !- Electric Power Minimum Flow Rate Fraction
    1200,                    !- Design Pressure Rise {Pa}
    0.9,                     !- Motor Efficiency
    1,                       !- Motor In Air Stream Fraction
    autosize,                !- Design Electric Power Consumption {W}
    TotalEfficiencyAndPressure,  !- Design Power Sizing Method
    ,                        !- Electric Power Per Unit Flow Rate {W/(m3/s)}
    ,                        !- Electric Power Per Unit Flow Rate Per Unit Pressure {W/((m3/s)-Pa)}
    0.7,                     !- Fan Total Efficiency
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Electric Power Function of Flow Fraction Curve Name
    ,                        !- Night Ventilation Mode Pressure Rise {Pa}
    ,                        !- Night Ventilation Mode Flow Fraction
    ,                        !- Motor Loss Zone Name
    ,                        !- Motor Loss Radiative Fraction
    General;                 !- End-Use Subcategory
    ,                        !- Number of Speeds
    ,                        !- Speed 1 Flow Fraction
    ,                        !- Speed 1 Electric Power Fraction

Fan curve input is as follows. It is based on ASHRAE90.1 TABLE G3.1.3.15. I think there should be no problem with it becuase AHUs that have been modelled with Fan:Variable and with the same coeciffients as this fan power curve have variable Fan Electric Power.

Curve:Cubic,
    ASHRAE90.1 TABLE G3.1.3.15 Fan Power Curve,  !- Name
    0.0013,                  !- Coefficient1 Constant
    0.147,                   !- Coefficient2 x
    0.9506,                  !- Coefficient3 x**2
    -0.0998,                 !- Coefficient4 x**3
    0,                       !- Minimum Value of x
    1;                       !- Maximum Value of x

AirLoopHVAC:DedicatedOutdoorAirSystem and Fan:SystemModel use the same Availability Schedule, so Fan:SystemModel should be OFF during midnight, but it isn't.

AirLoopHVAC:DedicatedOutdoorAirSystem,
    PAU_Tower12_Office_1,    !- Name
    PAU_Tower12_Office_1 OA System,  !- AirLoopHVAC:OutdoorAirSystem Name
    LEED_V4_OFFICE_VENTILATION,  !- Availability Schedule Name
    PAU_Tower12_Office_1 Zone Mixer,  !- AirLoopHVAC:Mixer Name
    PAU_Tower12_Office_1 Zone Splitter,  !- AirLoopHVAC:Splitter Name
    4.5,                     !- Preheat Design Temperature {C}
    0.004,                   !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
    17.5,                    !- Precool Design Temperature {C}
    0.012,                   !- Precool Design Humidity Ratio {kgWater/kgDryAir}
    5,                       !- Number of AirLoopHVAC
    VAV_TOWER12_28F,         !- AirLoopHVAC 1 Name
    VAV_TOWER12_26-27F,      !- AirLoopHVAC 2 Name
    VAV_TOWER12_25F,         !- AirLoopHVAC 3 Name
    VAV_TOWER12_23-24F,      !- AirLoopHVAC 4 Name
    VAV_TOWER12_22F;         !- AirLoopHVAC 5 Name