Switch from model HeatPump to ModularReversible

If you want to switch from the model AixLib.Fluid.HeatPumps.HeatPump (or Chillers.Chiller) to the new packages AixLib.Fluid.HeatPumps.ModularReversible, the following guide states all aspects you need to consider.

Naming changes

Aside from the points below, which can't be solved using a conversion script, you can use the following conversion script to ease the process. If you don't want to execute the script, read the changed names in the script to fix naming changes. To execute the script:

1. Start Dymola
2. Go to Simulation -> Run Script and run the following script AixLib\Resources\Scripts\ConvertHeatPumpToModularReversible.mos
3. Then and only then, load the package (e.g. AixLib or BESMod) you want to convert. All changes mentioned below require the removal of the old parameters, e.g. scalingFactor. They are not removed automatically to make the switch easier.

Sizing

In general, sizing now works using QHea_flow_nominal (and QCoo_flow_nominal for Chillers / cooling mode) specified at other nominal conditions, e.g. TConHea_nominal or TEvaHea_nominal. Please check the AixLib.Fluid.HeatPumps.ModularReversible.UsersGuide for more information. If you never though about sizing, you most probably kept scalingFactor=1 and use_autoCal=false. In this case, you have to look up any point in your performance data, e.g. 35 °C supply and 2 °C ambient temperature, set those as TConHea_nominal and TEvaHea_nominal and QHea_flow_nominal to the associated heat flow rate. For an example, check AixLib.Fluid.Examples.GeothermalHeatPump.BaseClasses.GeothermalHeatPumpBase.

Scaling Factor

If you used the scalingFactor, you most likely calculated it by needs of a certain heat flow rate at nominal conditions. This now happens automatically, by specifying QHea_flow_nominal (or QCoo_flow_nominal).

Automatic estimation

If you "enabled automatic estimation of volumes and mass flow rates" (use_autoCal=true), you have to use LargeScaleWaterToWater. Here, Q_useNominal is now QHea_flow_nominal (or QCoo_flow_nominal for Chillers). If you enabled this and simulated small scale devices, you extrapolated the regression data which is only valid for large scale water-to-water devices.

Safety control

If you used an external safety control, this is now internal. Just enable use_intSafCtr and select find the old parameters in the record. If you did not use this, you may set use_intSafCtr=false. The defrost control is not included in the safety control anymore. You have to externally control the defrost operation or within the icing factor model.

Icing factor / Defrost

The model to account for frosting (iceFac) moved from an external input connector to an internal calcuation at flowsheet level. Thus, you have to adapt your old model to the layout under AixLib.Fluid.HeatPumps.ModularReversible.RefrigerantCycle.Frosting and redeclare the default NoFrosting in the RefrigerantCycleHeatPumpHeating or RefrigerantCycleHeatPumpCooling.

Refrigerant inertia

The optional inertia is now more modular, enabling different approaches opposed to the standard PTn Element in the old version. If you have inertia enabled in the old version, redeclare the model RefrigerantCycleInertia with AixLib.Fluid.HeatPumps.ModularReversible.RefrigerantCycle.Inertias.VariableOrder and set the old parameters within the redeclared model.

Volume VCon and VEva

The volume is now what is acutally models, a time constant. To convert from V to tau, you can you the following equations: tauEva=VEva*heaPum.rhoEva/heaPum.mEva_flow_nominal tauCon=VCon*heaPum.rhoCon/heaPum.mCon_flow_nominal