[EnergyPlus_Support] power problem of the "Variable Speed Pump"

["oldgun_hbns" <fy_liu111@xxxxxxx>]

dear Mike:

some expressions about of the object "Variable Speed Pump" in 
engineeringReference.pdf:

  VolFlowRate = PumpMassFlowRate / LoopDensity
  PartLoadRatio = VolFlowRate / PumpEquip(PumpNum)%NomVolFlowRate
  FracFullLoadPower = PumpEquip(PumpNum)%PartLoadCoef(1) 
     + PumpEquip(PumpNum)%PartLoadCoef(2) * PartLoadRatio 
     + PumpEquip(PumpNum)%PartLoadCoef(3) * PartLoadRatio**2 
     + PumpEquip(PumpNum)%PartLoadCoef(4) * PartLoadRatio**3
  Power = FracFullLoadPower * PumpEquip(PumpNum)%NomPowerUse
  ShaftPower = Power * PumpEquip(PumpNum)%MotorEffic
  ! This adds the pump heat based on User input for the pump
  ! We assume that all of the heat ends up in the fluid eventually 
since this is a closed loop
  ! PumpHeattoFluid = ShaftPower*(1-PumpEquip(PumpNum)%PumpEffic) 
  PumpHeattoFluid = ShaftPower + (Power - ShaftPower)*PumpEquip
(PumpNum)%FracMotorLossToFluid
  Node(OutletNode)%Temp = Node(InletNode)%Temp+PumpHeattoFluid/
(PumpMassFlowRate * LoopCp)
  PumpEquip(PumpNum)%Power = Power

what meaning of the variable: "PumpEquip(PumpNum)",  "NomVolFlowRate" 
and "NomPowerUse"?
how to calculate the coefficient of cubic equation?  
universality only the PartLoadCoef(2) equal to 1 and other equal to 
0, imply the cubic equation is not usefulness.
                                   thanks.
                                      gun 
        



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