I using Energyplus to simulate two equal capacity chillers autosized to meet the cooling load for an office. I already read this question and I checked my IDF based on it: 1- I sized my chillers using autosize and size factor of 0.5
Chiller:Electric:ReformulatedEIR,
CoolSys1 Chiller1, !- Name
autosize, !- Reference Capacity {W}
6.28, !- Reference COP {W/W}
6.6700, !- Reference Leaving Chilled Water Temperature {C}
34.4444, !- Reference Leaving Condenser Water Temperature {C}
autosize, !- Reference Chilled Water Flow Rate {m3/s}
autosize, !- Reference Condenser Water Flow Rate {m3/s}
WC_CENT_2010_PB_CAPFT, !- Cooling Capacity Function of Temperature Curve Name
WC_CENT_2010_PB_EIRFT, !- Electric Input to Cooling Output Ratio Function of Temperature Curve Name
LeavingCondenserWaterTemperature, !- Electric Input to Cooling Output Ratio Function of Part Load Ratio Curve Type
WC_CENT_300to600_2010_PB_EIRFPLR, !- Electric Input to Cooling Output Ratio Function of Part Load Ratio Curve Name
0.1000, !- Minimum Part Load Ratio
1.0000, !- Maximum Part Load Ratio
1.0000, !- Optimum Part Load Ratio
0.1000, !- Minimum Unloading Ratio
CoolSys1 Pump-CoolSys1 Chiller1Node, !- Chilled Water Inlet Node Name
CoolSys1 Supply Equipment Outlet Node 1, !- Chilled Water Outlet Node Name
CoolSys1 Chiller1 Water Inlet Node, !- Condenser Inlet Node Name
CoolSys1 Chiller1 Water Outlet Node, !- Condenser Outlet Node Name
, !- Fraction of Compressor Electric Consumption Rejected by Condenser
5.0000, !- Leaving Chilled Water Lower Temperature Limit {C}
ConstantFlow, !- Chiller Flow Mode Type
0.0000, !- Design Heat Recovery Water Flow Rate {m3/s}
, !- Heat Recovery Inlet Node Name
, !- Heat Recovery Outlet Node Name
0.5; !- Sizing Factor
2- I used the operation scheme objects to specify the priority of using chillers.
PlantEquipmentOperationSchemes,
CoolSys1 Loop Operation Scheme List, !- Name
PlantEquipmentOperation:CoolingLoad, !- Control Scheme 1 Object Type
CoolSys1 Operation Scheme, !- Control Scheme 1 Name
PlantOnSched; !- Control Scheme 1 Schedule Name
PlantEquipmentOperation:CoolingLoad,
CoolSys1 Operation Scheme, !- Name
0, !- Load Range 2 Lower Limit {W}
100000000000000, !- Load Range 2 Upper Limit {W}
CoolSys1 Equipment List 2; !- Range 2 Equipment List Name
PlantEquipmentList,
CoolSys1 Equipment List 2, !- Name
Chiller:Electric:ReformulatedEIR, !- Equipment 1 Object Type
CoolSys1 Chiller1, !- Equipment 1 Name
Chiller:Electric:ReformulatedEIR, !- Equipment 2 Object Type
CoolSys1 Chiller2; !- Equipment 2 Name
3- I used the load distribution scheme in the plant loop definition:
PlantLoop,
CoolSys1_Demand, !- Name
Water, !- Fluid Type
, !- User Defined Fluid Type
CoolSys1 Sec Loop Operation, !- Plant Equipment Operation Scheme Name
CoolSys1 Demand Inlet Node, !- Loop Temperature Setpoint Node Name
98, !- Maximum Loop Temperature {C}
1, !- Minimum Loop Temperature {C}
autosize, !- Maximum Loop Flow Rate {m3/s}
0, !- Minimum Loop Flow Rate {m3/s}
autocalculate, !- Plant Loop Volume {m3}
CoolSys1 Demand Supply Side Inlet Pipe Inlet Node, !- Plant Side Inlet Node Name
CoolSys1 Demand Supply Side Outlet Pipe Outlet Node, !- Plant Side Outlet Node Name
CoolSys1 Demand Supply Side Branches, !- Plant Side Branch List Name
CoolSys1 Demand Supply Side Connectors, !- Plant Side Connector List Name
CoolSys1 Demand Inlet Node, !- Demand Side Inlet Node Name
CoolSys1 Demand Outlet Node, !- Demand Side Outlet Node Name
CoolSys1 Demand Demand Side Branches, !- Demand Side Branch List Name
CoolSys1 Demand Demand Side Connectors, !- Demand Side Connector List Name
SequentialLoad; !- Load Distribution Scheme
When I run the simulation for a day I receive weird load distribution as follow:
As can be seen, the first chiller doesn't reach its maximum PLR!!
I tried many modifications but no matter what, the load distribution doesn't work properly. Here is my idf file.
