modelHeatPumpHeatExchanger

Model of a substation with heat pump for heating, heat pump for domestic hot water, and compressor-less cooling

Extends from Buildings.DHC.ETS.Combined.BaseClasses.PartialHeatPumpHeatExchanger.

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 on-demand with no storage.

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.HeatPump.
  • The condensor water mass flow rate is computed based on the domestic hot water heating load (input QReqHotWat_flow) where the temperature of water is boosted from the domestic cold water temperature (input TColWat) to the desired domestic hot water distribution temperature (parameter THotWatSup_nominal), according to the following equation:

    QReqHotWat_flow = ṁ cp (THotWatSup_nominal - TColWat)

Components

TypeNameDefaultDescription
Buildings.DHC.ETS.Combined.Subsystems.HeatPumpproHotWatSubsystem for hot water production
Buildings.Fluid.Sources.Boundary_pTsouColWatSource for cold water
Buildings.Fluid.Sources.Boundary_pTsinSHWSink for service hot water
Buildings.Controls.OBC.CDL.Reals.Dividediv1Compute mass flow rate from load
Buildings.Controls.OBC.CDL.Reals.MultiplyByParametergaiTimes Cp
Buildings.Controls.OBC.CDL.Reals.SubtractdelTCompute DeltaT needed on condenser side

Revisions

  • March 27, 2024, by David Blum:
    Update icon.
    This is for issue #3606.
  • September 13, 2023, by David Blum:
    Extended from partial base class. This is for issue 3063.
  • May 17, 2023, by David Blum:
    Assigned dp_nominal to pum1HexChi.
    Corrected calculation of heat pump evaporator mass flow control.
    This is for issue 3379.
  • February 23, 2021, by Antoine Gautier:
    Refactored with subsystem models and partial ETS base class.
    This is for issue 1769.
  • December 12, 2017, by Michael Wetter:
    Removed call to Modelica.Utilities.Files.loadResource.
    This is for issue 1097.