Partial melting-freezing cycle of hysteresis PCM

asked 2020-11-02 21:11:21 -0500

y.gao@lbl.gov gravatar image

updated 2021-04-07 13:12:09 -0500

I'm using "MaterialProperty:PhaseChangeHysteresis" to simulate a PCM wall in Energyplus.

I notice that sometimes the PCM state could jump from -2 to +2, which triggered me doubt that this module might be designed only for the complete melting-freezing cycle of PCM.

The article "Hysteresis effects on the thermal performance of building envelope PCM-walls" mentioned several models of partial melting-freezing cycle of PCM, and no conclusive study was available.

I'm wondering how the algorithms in EnergyPlus handle the partial melting-freezing cycle of PCM, which is not mentioned in the manual. If EnergyPlus didn't fully consider the partial melting-freezing cycle of PCM, I should probably not use the hystersis property in the annual simulation.

This is the output defined in the idf file

Output:Variable,PCM_WALL,CondFD Inner Solver Loop Iteration Count,hourly; !- Zone Sum [] 
Output:Variable,PCM_WALL,CondFD Surface Temperature Node 1,hourly; !- Zone Average [C] 
Output:Variable,PCM_WALL,CondFD Surface Heat Flux Node 1,hourly; !- Zone Average [W/m2] 
Output:Variable,PCM_WALL,CondFD Phase Change State 1,hourly; !- Zone Average [] 
Output:Variable,PCM_WALL,CondFD Phase Change Previous State 1,hourly; !- Zone Average [] 
Output:Variable,PCM_WALL,CondFD Phase Change Node Temperature 1,hourly; !- Zone Average [C] 
Output:Variable,PCM_WALL,CondFD Surface Temperature Node 2,hourly; !- Zone Average [C]  
Output:Variable,PCM_WALL,CondFD Surface Heat Flux Node 2,hourly; !- Zone Average [W/m2] 
Output:Variable,PCM_WALL,CondFD Phase Change State 2,hourly; !- Zone Average [] 
Output:Variable,PCM_WALL,CondFD Phase Change Previous State 2,hourly; !- Zone Average [] 
Output:Variable,PCM_WALL,CondFD Phase Change Node Temperature 2,hourly; !- Zone Average [C]
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