.Buildings.DHC.ETS.Combined.HeatPumpHeatExchangerDHWTank

Information

This model uses the base energy transfer station defined in Buildings.DHC.ETS.Combined.BaseClasses.PartialHeatPumpHeatExchanger.

Domestic Hot Water

Domestic hot water is produced using a dedicated water-to-water heat pump with storage tank.

Heating is enabled based on the input signal uSHW which is held for 15 minutes, meaning that, when enabled, the mode remains active for at least 15 minutes and, when disabled, the mode cannot be enabled again for at least 15 minutes. The enable signal should be computed externally based on a schedule (to lock out the system during off-hours), ideally in conjunction with the number of requests or any other signal representative of the load.

When enabled,

• The heat pump and the evaporator and condenser hydronics are controlled based on the principles described in Buildings.DHC.ETS.Combined.Subsystems.HeatPumpDHWTank.
• The mass flow rate of water leaving the domestic hot water heat exchanger is computed based on the domestic hot water heating load (input QReqHotWat_flow) combined with the operation of a thermostatic mixing valve used to mix down the temperature of hot water leaving the domestic hot water heat exchanger to the temperature distributed to fixtures (parameter THotWatSup_nominal) using domestic cold water at the cold water temperature (input TColWat). The desired water flow rate leaving the thermostatic mixing valve is determined according to the following equation:

  QReqHotWat_flow = ṁ cp (THotWatSup_nominal - TColWat)

Revisions

• March 27, 2024, by David Blum:
  Update icon.
  This is for issue #3606.
• September 13, 2023, by David Blum:
  First implementation, extended from partial base class. This is for issue 3063.