modelHeatPump

Base subsystem with water-to-water heat pump
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Extends from Buildings.DHC.ETS.Combined.Subsystems.BaseClasses.PartialHeatPump (Partial base class for subsystems containing a heat pump).

Information

This model represents a water-to-water heat pump, an evaporator water pump, and a condenser water pump. The heat pump model is described in Buildings.Fluid.HeatPumps.Carnot_TCon. By default, a variable speed condenser pump is considered, but a constant speed pump may also be represented by setting have_varFloCon to false. The evaporator hydronics and control are described in Buildings.DHC.ETS.Combined.Subsystems.BaseClasses.PartialHeatPump.

Condenser Controls

The system is enabled when the input control signal uEna switches to true. When enabled, on the condenser side,

  • the condenser water pumps are commanded on and supply either the condenser mass flow rate set point provided as an input in the case of the variable speed condenser pump, or the nominal mass flow rate in the case of the constant speed condenser pump,
  • the heat pump controller—idealized in this model—tracks the supply temperature set point at the condenser outlet.

Parameters

TypeNameDefaultDescription
Modelica.Units.SI.MassFlowRatemCon_flow_nominal (from PartialHeatPump)heaPum.m1_flow_nominalCondenser mass flow rate
Modelica.Units.SI.MassFlowRatemEva_flow_nominal (from PartialHeatPump)heaPum.m2_flow_nominalEvaporator mass flow rate
Booleanhave_varFloContrueSet to true for a variable condenser flow
Nominal condition
RealCOP_nominal (from PartialHeatPump)Heat pump COP
Modelica.Units.SI.TemperatureTCon_nominal (from PartialHeatPump)Condenser outlet temperature used to compute COP_nominal
Modelica.Units.SI.TemperatureTEva_nominal (from PartialHeatPump)Evaporator outlet temperature used to compute COP_nominal
Modelica.Units.SI.TemperatureDifferencedT_nominal (from PartialHeatPump)5Water temperature drop/increase accross load and source-side HX (always positive)
Modelica.Units.SI.Pressuredp1_nominal (from PartialHeatPump)Pressure difference over condenser
Modelica.Units.SI.Pressuredp2_nominal (from PartialHeatPump)Pressure difference over evaporator
Modelica.Units.SI.HeatFlowRateQ1_flow_nominalHeating heat flow rate
Assumptions
BooleanallowFlowReversal1 (from PartialHeatPump)falseSet to true to allow flow reversal on condenser side
BooleanallowFlowReversal2 (from PartialHeatPump)falseSet to true to allow flow reversal on evaporator side

Connectors

TypeNameDefaultDescription
Modelica.Fluid.Interfaces.FluidPort_aport_a2 (from PartialHeatPump)Fluid port for entering evaporator water
Modelica.Fluid.Interfaces.FluidPort_bport_b2 (from PartialHeatPump)Fluid port for leaving evaporator water
Modelica.Fluid.Interfaces.FluidPort_aport_a1 (from PartialHeatPump)Fluid port for cold domestic water
Modelica.Fluid.Interfaces.FluidPort_bport_b1 (from PartialHeatPump)Fluid port for heated domestic hot water
Buildings.Controls.OBC.CDL.Interfaces.RealOutputPHea (from PartialHeatPump)Heat pump power
Buildings.Controls.OBC.CDL.Interfaces.RealOutputPPum (from PartialHeatPump)Pump power
Buildings.Controls.OBC.CDL.Interfaces.RealOutputmEva_flow (from PartialHeatPump)Evaporator water mass flow rate
Buildings.Controls.OBC.CDL.Interfaces.BooleanInputuEna (from PartialHeatPump)Enable signal
Buildings.Controls.OBC.CDL.Interfaces.RealInputTSupSetSupply temperature set point
Buildings.Controls.OBC.CDL.Interfaces.RealInputm1_flowCondenser mass flow rate

Components

TypeNameDefaultDescription
Buildings.Fluid.HeatPumps.Carnot_TConheaPum (from PartialHeatPump)Domestic hot water heat pump
Buildings.DHC.ETS.BaseClasses.Pump_m_flowpumCon (from PartialHeatPump)Pump for heat pump condenser
Buildings.Fluid.Movers.Preconfigured.SpeedControlled_ypumEva (from PartialHeatPump)Heat pump evaporator water pump
Modelica.Blocks.Math.AddaddPPum (from PartialHeatPump)Electricity use for pumps
Buildings.Controls.OBC.CDL.Conversions.BooleanToRealfloEva (from PartialHeatPump)Evaporator mass flow rate
Fluid.Actuators.Valves.ThreeWayEqualPercentageLinearvalHeaPumEva (from PartialHeatPump)Valve at heat pump evaporator
Fluid.Sensors.TemperatureTwoPortsenTEvaRet (from PartialHeatPump)Evaporator return temperature sensor
Fluid.Sensors.TemperatureTwoPortsenTDisSup (from PartialHeatPump)District supply temperature sensor
Buildings.Controls.OBC.CDL.Reals.SubtractdT_supRet (from PartialHeatPump)Temperature difference over heat pump connection
Buildings.Controls.OBC.CDL.Reals.Sources.ConstantdTSet (from PartialHeatPump)Set point for temperature difference over heat pump
Buildings.Controls.OBC.CDL.Reals.PIDWithResetconPI (from PartialHeatPump)Controller to ensure dT_nominal over heat pump connection
Fluid.Sensors.MassFlowRatesenMasFlo (from PartialHeatPump)Mass flow rate drawn from ETS
Buildings.DHC.ETS.BaseClasses.Junctionjunction (from PartialHeatPump)
Buildings.Controls.OBC.CDL.Reals.Sources.ConstantfloConNomNominal flow rate
Buildings.Controls.OBC.CDL.Conversions.BooleanToRealbooToRea
Buildings.Controls.OBC.CDL.Reals.MultiplyfloConZero flow rate if not enabled

Revisions

  • November 15, 2023, by David Blum:
    Changed to extend partial base class with added condenser hydronics and control.
  • May 3, 2023, by David Blum:
    Assigned dp_nominal to condenser pump.
    This is for issue 3379.
  • November 16, 2022, by Michael Wetter:
    Set pumEva.dp_nominal to correct value.
  • February 23, 2021, by Antoine Gautier:
    First implementation.