The Basic phase change option describes a single process curve whereby a material moves from a crystallized to liquid state and back. This option models the same process but also includes a hysteresis effect, allowing the melting and freezing processes to follow different curves, representing an effect that is commonly seen in actual building envelope phase change material applications. This option also allows the characteristic properties of the processes to be entered instead of a detailed temperature/enthalpy curve, making it more amenable for studies in which the user does not have the detailed test data required to generate the temperature/enthalpy curve.
When the Phase change material check box is selected, this material is simulated as having the following temperature dependent material properties.
Choose from two methods to model PCMs:
This is the total amount of latent heat absorbed or discharged during the transition from solid to liquid or back (in J or Btu/lb). The shapes of the enthalpy curves differ based on direction, but the total amount of energy from one state to the other does not.
This is the constant thermal conductivity used while the material is fully liquid (in W/m-K or Btu-in/h-ft2-°F).
This is the constant density while the material is fully liquid (in kg/m3 or lb/ft3).
This is the constant specific heat while the material is fully liquid (in J/kg-K or Btu/lb-°F).
This is the width of the enthalpy/specific heat melting curve, on the high side of the peak melting temperature (in Delta °C or Delta °F).
This is the centre (peak) of the melting curve (in °C or °F).
This is the width of the enthalpy/specific heat melting curve, on the low side of the peak melting temperature (in Delta °C or Delta °F).
This is the constant thermal conductivity used while the material is fully solid (in W/m-K or Btu-in/h-ft2-°F).
This is the constant density while the material is fully solid (in kg/m3 or lb/ft3).
This is the constant specific heat while the material is fully crystallized (in J/kg-K or Btu/lb-°F).
This is the width of the enthalpy/specific heat freezing curve, on the high side of the peak freezing temperature (Delta °C or Delta °F).
This is the center (peak) of the freezing curve (in °C or °F). This will be higher than the peak melting temperature based on empirical data.
This is the width of the enthalpy/specific heat freezing curve, on the low side of the peak freezing temperature (Delta °C or Delta °F).