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[EnergyPlus_Support] Re: Fwd: Central Heat Production vs terminal units
Thanks.
I based my adpated model on that Example File, and I've checked again
now... I think that node connections and the like are correct...
I get some warnings about freezing possibility, but other than that,
it seems OK... except that the Heat Pump DX Coil gives a lot more
energy than is being used by the demand side coils.
I'll keep trying to find out the bug, I guess...
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Richard Raustad
<RRaustad@...> wrote:
>
> 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
> Visit our web site at: http://www.fsec.ucf.edu
>
> UCF - From Promise to Prominence: Celebrating 40 Years
>
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