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Re: [EnergyPlus_Support] Fwd: Central Heat Production vs terminal units



Look at the example file HeatPumpWaterHeater.idf. In your file, hook up 
the plant loop to the USE SIDE nodes in the WaterHeater:Mixed object. 
Just use a 1 for the use side effectiveness value.

  HEAT PUMP:WATER HEATER,
    Zone5HeatPumpWaterHeater,!- Heat Pump Name
    HeatPumpWaterHeaterSch,  !- Availability Schedule Name
    HPWHTempSch,             !- Heat Pump Compressor Set Point 
Temperature Schedule Name
    2.0,                     !- Dead Band Temperature Difference {deltaC}
    HPWHWaterInletNode,      !- Condenser Water Inlet Node Name
    HPWHWaterOutletNode,     !- Condenser Water Outlet Node Name
    autocalculate,           !- Condenser Water Volumetric Flow Rate {m3/s}
    autocalculate,           !- Evaporator Air Volumetric Flow Rate {m3/s}
    Zone and Outdoor Air,    !- Inlet Air Configuration
    HPWHAirOutletNode,       !- Heat Pump Air Inlet Node Name
    HPWHAirInletNode,        !- Heat Pump Air Outlet Node Name
    HPWHOutdoorAirInletNode, !- Outside Air Node Name
    HPWHExhaustAirOutletNode,!- Exhaust Air Node Name
    ,                        !- Inlet Air Temperature Schedule Name
    ,                        !- Inlet Air Humidity Schedule Name
    SPACE5-1,                !- Inlet Air Zone Name
    Water Heater:Mixed,      !- Water Heater Tank Type
    HPWHTank,                !- Water Heater Tank Name
    ,                        !- Water Heater Tank Use Side Inlet Node Name
    ,                        !- Water Heater Tank Use Side Outlet Node Name
    Coil:DX:HeatPumpWaterHeater,  !- DX Coil Type
    HPWHDXCoil,              !- DX Coil Name
    5.0,                     !- Minimum Inlet Air Temperature for Heat 
Pump Compressor Operation {C}
    Zone,                    !- Compressor Location
    ,                        !- Compressor Ambient Temperature Schedule Name
    Fan:Simple:OnOff,        !- Fan Type
    HPWHFan,                 !- Fan Name
    Draw Through,            !- Fan Placement
    15.0,                    !- On-Cycle Parasitic Electric Load {W}
    5.0,                     !- Off-Cycle Parasitic Electric Load {W}
    Zone,                    !- Parasitic Heat Rejection Location
    HPWHInletAirMixerNode,   !- Inlet Air Mixer Node Name
    HPWHOutletAirSplitterNode,  !- Outlet Air Splitter Node Name
    HPWHMixerInletAirSch;    !- Inlet Air Mixer Schedule Name


  WATER HEATER:MIXED,
    HPWHTank,                !- Name
    0.3785,                  !- Tank Volume {m3}
    Hot Water Setpoint Temp Schedule,  !- Setpoint Temperature Schedule
    2.0,                     !- Deadband Temperature Difference {deltaC}
    82.2222,                 !- Maximum Temperature Limit {C}
    CYCLE,                   !- Heater Control Type
    5000,                    !- Heater Maximum Capacity {W}
    0,                       !- Heater Minimum Capacity {W}
    ,                        !- Heater Ignition Minimum Flow Rate {m3/s}
    ,                        !- Heater Ignition Delay {s}
    ELECTRICITY,             !- Heater Fuel Type
    0.95,                    !- Heater Thermal Efficiency
    ,                        !- Part Load Factor Curve
    10,                      !- Off-Cycle Parasitic Fuel Consumption 
Rate {W}
    ELECTRICITY,             !- Off-Cycle Parasitic Fuel Type
    0,                       !- Off-Cycle Parasitic Heat Fraction To Tank
    30,                      !- On-Cycle Parasitic Fuel Consumption Rate {W}
    ELECTRICITY,             !- On-Cycle Parasitic Fuel Type
    0,                       !- On-Cycle Parasitic Heat Fraction To Tank
    ZONE,                    !- Ambient Temperature Indicator
    ,                        !- Ambient Temperature Schedule
    SPACE5-1,                !- Ambient Temperature Zone
    ,                        !- Ambient Temperature Outside Air Node
    2.0,                     !- Off-Cycle Loss Coefficient To Ambient 
Temperature {W/K}
    1.0,                     !- Off-Cycle Loss Fraction To Zone
    2.0,                     !- On-Cycle Loss Coefficient To Ambient 
Temperature {W/K}
    1.0,                     !- On-Cycle Loss Fraction To Zone
    0.00379,                 !- Peak Volumetric Use Flow Rate {m3/s}
    Hot Water Demand Schedule,  !- Use Flow Rate Fraction Schedule
    ,                        !- Cold Water Supply Temperature Schedule
  ,             !- Use Side Inlet Node
  ,             !- Use Side Outlet Node
  ,             !- Use Side Effectiveness
    HPWHWaterOutletNode,     !- Source Side Inlet Node
    HPWHWaterInletNode,      !- Source Side Outlet Node
    0.95;                    !- Source Side Effectiveness


  COIL:DX:HEATPUMPWATERHEATER,
    HPWHDXCoil,              !- Coil Name
    4000.0,                  !- Heating Capacity {W}
    3.2,                     !- Rated COP {W/W}
    0.6956,                  !- Rated SHR (gross)
    29.44,                   !- Rated Evaporator Inlet Air Dry-Bulb 
Temperature {C}
    22.22,                   !- Rated Evaporator Inlet Air Wet-Bulb 
Temperature {C}
    55.72,                   !- Rated Condenser Inlet Water Temperature {C}
    autocalculate,           !- Rated Evaporator Air Volumetric Flow 
Rate {m3/s}
    autocalculate,           !- Rated Condenser Water Volumetric Flow 
Rate {m3/s}
    No,                      !- Evaporator Fan Power Included in Rated COP
    No,                      !- Condenser Pump Power Included in Rated COP
    No,                      !- Condenser Pump Heat Included in Rated 
Heating Capacity and Rated COP
    150.0,                   !- Condenser Water Pump Power {W}
    0.1,                     !- Fraction of Condenser Pump Heat to Water
    HPWHInletAirMixerNode,   !- Evaporator Air Inlet Node Name
    HPWHDXCoilAirOutletNode, !- Evaporator Air Outlet Node Name
    HPWHWaterInletNode,      !- Condenser Water Inlet Node Name
    HPWHWaterOutletNode,     !- Condenser Water Outlet Node Name
    100.0,                   !- Crankcase Heater Capacity {W}
    5.0,                     !- Maximum Ambient Temperature for 
Crankcase Heater Operation {C}
    wet-bulb temperature,    !- Evaporator Air Temperature Type for 
Curve Objects
    HPWHHeatingCapFTemp,     !- Heating Capacity Modifier Curve Name 
(function of temperature)
    ,                        !- Heating Capacity Modifier Curve Name 
(function of air flow fraction)
    ,                        !- Heating Capacity Modifier Curve Name 
(function of water flow fraction)
    HPWHHeatingCOPFTemp,     !- Heating COP Modifier Curve Name 
(function of temperature)
    ,                        !- Heating COP Modifier Curve Name 
(function of air flow fraction)
    ,                        !- Heating COP Modifier Curve Name 
(function of water flow fraction)
    HPWHPLFFPLR;             !- Part Load Fraction Correlation Name 
(function of part load ratio)

anarui.oliveira wrote:
>
> Maybe this additional information helps:
>
> ...I started out with a model of a boiler created with Compact HVAC,
> and then expanded it and substituted the boiler by the Heat Pump Water
> Heater.
> The expanded model with the boiler works fine... so I guess I missed
> something when adapting it to a model with a heat pump?...
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx 
> <mailto:EnergyPlus_Support%40yahoogroups.com>, "anarui.oliveira"
> <anarui.oliveira@...> wrote:
>
> Hi everyone.
>
> I modelled a system with a central Heat pump (air-to-water), producing
> heat for a hot water loop serving 3 Air Treatment Units and some
> terminal unit ventilators, but the thermal heating rate/energy produced
> by the central heat pump is much (2-3 times) higher than the sum of the
> heating rates/energy of all the coils in the ATUs and terminal units...
> It seems as if the control os this central unit is not performing
> properly, but I can't figure out why...
>
> Could anyone help?
>
> Thanks in advance,
> Ana Rui.
>
> --- End forwarded message ---
>
>  

-- 
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
1679 Clearlake Road
Cocoa, FL  32922-5703
Phone:   (321) 638-1454
Fax:     (321) 638-1439 or 1010
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