pcm Hysteresis vs Temperature-Enthalpy pair? [closed]

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Hello everyone! I am now doing a simulation of a single room with a simple HVAC operation and applying a PCM layer on the ceiling surface of the room. I have done two simulations with EnergyPlus and to accommodate the PCM, I used the PhaseChangeHysteresis and PhaseChange based on Temperature-Enthalpy pairs (according to the EnergyPlus link text.

I used the same melting temperature for both cases and the physical properties of each PCM setting are the same. However, the simulation results showed that the energy use for the room is different.

Can you explain why it happened? Thank you