Definitive right way to model a WSHP loop
I've checked all the available example files (especially 5ZoneWaterLoopHeatPump.idf
and HospitalLowEnergy.idf
), and done my own experimentation. I'm wondering what's really the best way to model a Water Source Heat Pump Loop with the following characteristics:
- There is one heating element (a
HeatExchanger:FluidToFluid
with Control Type set toHeatingSetpointModulated
, but could be aBoiler:HotWater
) - There is one cooling element (a
HeatExchanger:FluidToFluid
set toCoolingSetpointModulated
, but could be aChiller:Electric:EIR
) - The loop temperature should be between 18C (heating dominated) and 26C (cooling dominated), nothing to do in between.
A few options emerge:
- Should the heating element and cooling elements be:
- in parallel, or,
- on the same branch?
Should the Plant Loop Demand Calculation Scheme be:
DualSetpointWithDeadband
: place aSetpointManager:Scheduled:DualSetpoint
with a high temp schedule of 26C and a low temp schedule of 18C on the supply outlet of the plant loop, the heating element outlet node, and the cooling element outlet node (note: all SPMs must be DualSetpoint in this case, meaningSetpointManager:Scheduled
isn't an option for each equipment outlet) (5ZoneWaterLoopHeatPump
)SingleSetpoint
: place a SetpointManager:Scheduled on the supply outlet of the plant loop, actuate this setpoint schedule value with EMS by looking at the supply pump outlet temp: if pump outlet temp <= 18 then 18C, else if over 26C then 26C, in else plant supply outlet temp = pump outlet temp (HospitalLowEnergy
). Should you place a SPM:Scheduled with a value of 18C after the heating element and one with 26C after the cooling element?
What PlantEquipmentOperationScheme to use? I'd use a
PlantEquipmentOperation:HeatingLoad
with the heating element on it, and aPlantEquipmentOperation:CoolingLoad
with the cooling element on it. (HospitalLowEnergy
also uses aPlantEquipmentOperation:ComponentSetpoint
)
Thoughts? Proof that the loop temp is controlled properly?