modelHP_AirWater_TSet

Air-to-water heat pump with temperature set point

Extends from IDEAS.Fluid.HeatPumps.Interfaces.PartialDynamicHeaterWithLosses.

Information

Description

Dynamic heat pump model, based on interpolation in performance tables for a Daikin Altherma heat pump. These tables are encoded in the IDEAS.Fluid.HeatPumps.BaseClasses.HeatSource_HP_AW model. If a different heat pump is to be simulated, create a different heatSource model with adapted interpolation tables.

The nominal power of the heat pump can be adapted. This will NOT influence the efficiency as a function of ambient air temperature, condenser temperature and modulation level.

The heat pump has thermal losses to the environment which are often not mentioned in the performance tables. Therefore, the additional environmental heat losses are added to the heat production in order to ensure the same performance as in the manufacturers data, while still obtaining a dynamic model with heat losses (also when heat pump is off). The heatSource component will compute the required power and the environmental heat losses, and try to reach the setpoint.

See IDEAS.Fluid.HeatPumps.Interfaces.PartialDynamicHeaterWithLosses for more details about the heat losses and dynamics.

Assumptions and limitations

  • Dynamic model based on water content and lumped dry capacity
  • Inverter-controlled heat pump with limited power (based on QNom and interpolation tables in IDEAS.Fluid.HeatPumps.BaseClasses.HeatSource_HP_AW)
  • Heat losses to environment which are compensated 'artifically' to meet the manufacturers data in steady state conditions
  • No defrosting taken into account
  • No enforced minimum on or minimum off time. Hysteresis on start/stop thanks to different parameters for minimum modulation to start and stop the heat pump

Model use

  1. Specify medium and initial temperature (of the water + dry mass)
  2. Specify the nominal power QNom. There are two options:
    1. Specify QNom and put QDesign = 0
    2. Specify QDesign greater than 0 and QNom wil be calculated from QDesign as follows: QNom = QDesign * betaFactor / fraLosDesNom
  3. Connect TSet, the flowPorts and the heatPort to environment.
  4. Specify the minimum required modulation level for the heat pump to start (modulation_start) and the minimum modulation level when the heat pump is operating (modulation_min). The difference between both will ensure some off-time in case of low heat demands

Note that this model is based on performance tables of a specific heat pump, as specified by the IDEAS.Fluid.HeatPumps.BaseClasses.HeatSource_HP_AW model. If a different heat pump is to be simulated, create a different heatSource model with adapted interpolation tables.

Validation

Example

A specific heat pump example is given in IDEAS.Fluid.HeatPumps.Examples.HeatPump_AirWater.

Parameters

TypeNameDefaultDescription
BooleanuseQDesignabs(QDesign) > Modelica.Constants.small= true, QDesign is used to determine the heat pump's nominal thermal power
Modelica.Units.SI.PowerQNomFinalif not useQDesign then QNom else QDesign/fraLosDesNom*betaFactorUsed nominal thermal power of the heat pump in the heatSource model
BooleanuseMinModtrue=true, the heat pump has a minimum modulation degree
Design load
Modelica.Units.SI.PowerQDesign0Overrules QNom if different from 0. Design heat load, typically at -8°C in Belgium
RealfraLosDesNom0.68Ratio of power at design conditions over power at 2/35°C. Only used if QDesign is bigger than 0.
RealbetaFactor0.8Relative sizing compared to design heat load. Only used if QDesign is bigger than 0.
Nominal condition
Realmodulation_min20Minimal modulation percentage
Realmodulation_start35Minimal estimated modulation level required for start of HP

Components

TypeNameDefaultDescription
IDEAS.BoundaryConditions.SimInfoManagersim
RealCOPInstanteanous COP
RealmodulationIDEAS.Utilities.Math.Functions.smoothMax(0, heatSource.modulation, 1)Current modulation percentage
IDEAS.Fluid.HeatPumps.BaseClasses.HeatSource_HP_AWheatSource
Modelica.Blocks.Sources.BooleanExpressionbooleanExpression
Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensorTenv
Modelica.Blocks.Sources.RealExpressionTeva

Revisions

  • April 27, 2026, by Jelger Jansen:
    Revise and clean up model.
    See #1485.
  • February 4, 2025, by Jelger Jansen:
    Added Modelica.Units. to one or multiple parameter(s) due to the removal of import in IDEAS/package.mo. See #1415 .
  • September 10, 2020 by Filip Jorissen:
    Fixed real equality comparison for #1172.
  • June 5, 2018 by Filip Jorissen:
    Cleaned up implementation for #821.
  • March, 2014, by Filip Jorissen:
    Annex60 compatibility
  • May, 2013, by Roel De Coninck:
    Propagation of heatSource parameters and better definition of QNom used. Documentation and example added
  • 2011, by Roel De Coninck:
    First version