A bug report. When we try to override Pump Pressure Rise of HeaderedPumps:VariableSpeed or HeaderedPumps:ConstantSpeed with any value by EMS, Pump Electricity Rate becomes almost 0 W, probably because Pump Pressure Rise becoms almost 0 Pa.
I reproduced the bug with an ExampleFile HeaderedPumpsVarSpeed.idf. The idf file is here (V23-2-0). I added EMS as follows.
HeaderedPumps:VariableSpeed,
Chilled Water Headered Pumps, !- Name
CW Supply Inlet Node, !- Inlet Node Name
CW Pumps Outlet Node, !- Outlet Node Name
autosize, !- Total Design Flow Rate {m3/s}
2, !- Number of Pumps in Bank
SEQUENTIAL, !- Flow Sequencing Control Scheme
179352, !- Design Pump Head {Pa}
autosize, !- Design Power Consumption {W}
0.9, !- Motor Efficiency
0.0, !- Fraction of Motor Inefficiencies to Fluid Stream
0, !- Coefficient 1 of the Part Load Performance Curve
1, !- Coefficient 2 of the Part Load Performance Curve
0, !- Coefficient 3 of the Part Load Performance Curve
0, !- Coefficient 4 of the Part Load Performance Curve
0.1, !- Minimum Flow Rate Fraction
INTERMITTENT, !- Pump Control Type
CoolingPumpAvailSched, !- Pump Flow Rate Schedule Name
, !- Zone Name
, !- Skin Loss Radiative Fraction
PowerPerFlowPerPressure, !- Design Power Sizing Method
, !- Design Electric Power per Unit Flow Rate {W/(m3/s)}
, !- Design Shaft Power per Unit Flow Rate per Unit Head {W/((m3/s)-Pa)}
Pump Energy; !- End-Use Subcategory
EnergyManagementSystem:Actuator,
ChilledWaterHeaderedPumps_PressureRise, !- Name
Chilled Water Headered Pumps, !- Actuated Component Unique Name
Pump, !- Actuated Component Type
Pump Pressure Rise; !- Actuated Component Control Type
EnergyManagementSystem:ProgramCallingManager,
EMS_PCM_PumpPressureOverride, !- Name
InsideHVACSystemIterationLoop, !- EnergyPlus Model Calling Point
EMS_Program_PumpPressureRiseOverride; !- Program Name 1
EnergyManagementSystem:Program,
EMS_Program_PumpPressureRiseOverride, !- Name
SET ChilledWaterHeaderedPumps_PressureRise = 358704; !- Program Line 1
I doubled the Pump Pressure Rise of Chilled Water Headered Pumps i.e. I changed it from 179352Pa to 358704Pa. The original Design Power Consumption of the Chilled Water Headered Pumps is 353.18 W. So, the Pump Electricity Rate after I added EMS is supposed to be between 0W to 706.36 W. However, the result shows that it is 1.25872157206094E-306 W (the red line on the chart below).
The bug does not occur with Pump:VariableSpeed and Pump:ConstantSpeed. Only headered pumps have the bug.
