Problem with WaterHeater:HeatPump:PumpedCondenser

asked 2018-02-21 09:25:55 -0500

Marc70 gravatar image

updated 2018-02-21 14:37:28 -0500

Hello, when I insert a WaterHeater:HeatPump:PumpedCondenser in the loop, I have two problems: - the water temperature doesn't respect the setpoint temperature imposed on the loop (SetpointManager:OutdoorAirReset) - the Water Heater Heat Transfer Rate in the source side is really different from the Heat Transfer Rate in the use side. Can you tell me why? And with this type of heat pump, the heater is considered intern to the tank, so is right that inlet and outlet temperature of tank in the source side are the same, or is in parallel with this, so the source side inlet water temperature should be the hot water heated by heat pump condenser? Below there is a part of the text of idf file. Thanks

WaterHeater:Stratified,
HP Tank,                 !- Name
,                        !- End-Use Subcategory
3,                       !- Tank Volume {m3}
2.6,                     !- Tank Height {m}
VerticalCylinder,        !- Tank Shape
,                        !- Tank Perimeter {m}
90,                      !- Maximum Temperature Limit {C}
MasterSlave,             !- Heater Priority Control
SetHPtank_1 Temp,        !- Heater 1 Setpoint Temperature Schedule Name
2,                       !- Heater 1 Deadband Temperature Difference {deltaC}
338000,                  !- Heater 1 Capacity {W}
2.4,                     !- Heater 1 Height {m}
SetHPtank_2 Temp,        !- Heater 2 Setpoint Temperature Schedule Name
2,                       !- Heater 2 Deadband Temperature Difference {deltaC}
0,                       !- Heater 2 Capacity {W}
0.266,                   !- Heater 2 Height {m}
Electricity,             !- Heater Fuel Type
1,                       !- Heater Thermal Efficiency
8.3,                     !- Off Cycle Parasitic Fuel Consumption Rate {W}
Electricity,             !- Off Cycle Parasitic Fuel Type
0,                       !- Off Cycle Parasitic Heat Fraction to Tank
1,                       !- Off Cycle Parasitic Height {m}
8.3,                     !- On Cycle Parasitic Fuel Consumption Rate {W}
Electricity,             !- On Cycle Parasitic Fuel Type
0,                       !- On Cycle Parasitic Heat Fraction to Tank
1,                       !- On Cycle Parasitic Height {m}
Outdoors,                !- Ambient Temperature Indicator
,                        !- Ambient Temperature Schedule Name
,                        !- Ambient Temperature Zone Name
Centrale termofrigorifera,  !- Ambient Temperature Outdoor Air Node Name
0.7878,                  !- Uniform Skin Loss Coefficient per Unit Area to Ambient Temperature {W/m2-K}
0,                       !- Skin Loss Fraction to Zone
,                        !- Off Cycle Flue Loss Coefficient to Ambient Temperature {W/K}
0,                       !- Off Cycle Flue Loss Fraction to Zone
,                        !- Peak Use Flow Rate {m3/s}
,                        !- Use Flow Rate Fraction Schedule Name
,                        !- Cold Water Supply Temperature Schedule Name
HW SL BufferHeatPump Inlet,  !- Use Side Inlet Node Name
HW SL BufferHeatPump Outlet,  !- Use Side Outlet Node Name
1,                       !- Use Side Effectiveness
0.2,                     !- Use Side Inlet Height {m}
2.4,                     !- Use Side Outlet Height {m}
HW Source HeatPump Outlet,  !- Source Side Inlet Node Name
HW Source HeatPump Inlet,!- Source Side Outlet Node Name
1,                       !- Source Side Effectiveness
2.4,                     !- Source Side Inlet Height {m}
0.2,                     !- Source Side Outlet Height {m}
Fixed,                   !- Inlet Mode
autosize,                !- Use Side Design Flow Rate {m3/s}
,                        !- Source Side Design Flow Rate {m3/s}
,                        !- Indirect Water Heating Recovery Time {hr}
12;                      !- Number of Nodes

Coil:WaterHeating:AirToWaterHeatPump:Pumped,
HP Evaporetor,           !- Name
338000,                  !- Rated Heating Capacity {W}
3.26,                    !- Rated COP {W/W}
0.7,                     !- Rated Sensible Heat Ratio
7,                       !- Rated Evaporator Inlet Air Dry-Bulb Temperature {C}
6,                       !- Rated Evaporator Inlet Air Wet-Bulb Temperature {C}
40,                      !- Rated Condenser Inlet Water Temperature {C}
36.797,                  !- Rated Evaporator ...
(more)
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