modelLiangAndZhuCalibrated
Extends from AixLib.Fluid.HeatPumps.ModularReversible.RefrigerantCycle.Frosting.BaseClasses.PartialVelocityBased (Partial model for velocity based frost modelling).
Information
This model calibrates the growth velocities from Liang et al., who base their work on the zones from Zhu et al., onto dynamic frost densities and a custom build heat pump at the Institute for Energy Efficient Buildings and Indoor Climate.
The calibration was performed and used for Römer et al. In addition to Liang et al., a time-delay after the last defrost is used before the frost starts to grow again. This was added based observed data from dynamic tests and is grounded in the fact that fins are warm after defrost, and, thus, don't directly accumulate frost.
For more information, see the base-model: AixLib.Fluid.HeatPumps.ModularReversible.RefrigerantCycle.Frosting.BaseClasses.PartialVelocityBased .
References
Römer, Fabian and Fuchs, Nico and Fuchs, Nico and Müller, Dirk, Practical, Near-Optimal Design Rule Extraction for Heat Pumps in Single-Family Buildings (September 03, 2025). Available at SSRN: https://ssrn.com/abstract=5633891
J.H. Zhu, Y.Y. Sun, W. Wang, S.M. Deng, Y.J. Ge, and L.T. Li. Developing a new frosting map to guide defrosting control for air-source heat pump units. Applied Thermal Engineering, November 2015 doi:10.1016/j.applthermaleng.2015.06.076.
Liang, S., Wang, W., Sun, Y., Li, Z., Zhao, J., Lin, Y., and Deng, S. (2020). A novel characteristic index for frosting suppression based on the configuration and operation of air source heat pumps. International Journal of Refrigeration, 109, 161-171. https://doi.org/10.1016/j.ijrefrig.2019.10.009.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Area | A (from PartialVelocityBased) | 15 | Area of heat exchanger, all fins from both sides |
| Boolean | use_reset (from PartialVelocityBased) | false | = true, if reset port enabled |
| Real | timeMil | timeSev*facSevMil | |
| Real | defrostEfficiency | 0.65 | Defrost efficiency |
| Real | facSevMil | 1.358403 | |
| Real | timeSev | 1083.524850 | |
| Real | corCoeffSev | 0.231588 | Correction coefficient for severe zone |
| Real | corCoeffMod | 0.218708 | Correction coefficient for moderate zone |
| Real | corCoeffMil | 0.218708 | Correction coefficient for mild zone |
| Advanced › Medium properties | |||
| Modelica.Units.SI.SpecificHeatCapacity | cpEva (from PartialIcingFactor) | Evaporator medium specific heat capacity | |
| Density | |||
| Boolean | use_varDen (from PartialVelocityBased) | false | =true to use variable density based on PT1 Element, e.g. Korn et al. |
| Modelica.Units.SI.Density | den_constant (from PartialVelocityBased) | 659 | Constant density of frost, based on Korn at -5 frost temperature |
| Real | k (from PartialVelocityBased) | 3.77 | Gain |
| Modelica.Units.SI.Time | T (from PartialVelocityBased) | 8000 | Time Constant |
| Real | den_min (from PartialVelocityBased) | 50 | Minimal density |
| Ice mass | |||
| Boolean | estimateMaximalIceMass (from PartialVelocityBased) | true | =false to specify maximal ice mass directly |
| Modelica.Units.SI.Mass | mIce_max (from PartialVelocityBased) | den_constant*A*d/2 | Maximal possible mass of ice on HE surface. This value is limited by the volume between the fin tube |
| Modelica.Units.SI.Distance | d (from PartialVelocityBased) | 3e-3 | Distance between two fins. Used to calculate the maximal mass of ice on the HE |
| Melting | |||
| Real | natConvCoeff (from PartialVelocityBased) | 1e-7 | Parameter to be calibrated for natural defrost |
| Modelica.Units.SI.SpecificEnthalpy | hWatFus (from PartialVelocityBased) | 333.5e3 | Fusion enthalpy of water |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| AixLib.Fluid.HeatPumps.ModularReversible.BaseClasses.RefrigerantMachineControlBus | sigBus (from PartialIcingFactor) | Bus-connector used in a heat pump | |
| Modelica.Blocks.Interfaces.RealOutput | iceFac (from PartialIcingFactor) | Icing factor from 0 to 1 to estimate influence of icing |
Components
Revisions
-
December 22, 2025 by Fabian Roemer:
First implementation (see issue AixLib #1623)