Verification and validation of EnergyPlus phase change material model for opaque wall assemblies

Phase change materials (PCMs) represent a technology that may reduce peak loads and HVAC energy consumption in buildings. A few building energy simulation programs have the capability to simulate PCMs, but their accuracy has not been completely tested. This study shows the procedure used to verify and validate the PCM model in EnergyPlus using a similar approach as dictated by ASHRAE Standard 140, which consists of analytical verification, comparative testing, and empirical validation. This process was valuable, as two bugs were identified and fixed in the PCM model, and version 7.1 of EnergyPlus will have a validated PCM model. Preliminary results using whole-building energy analysis show that careful analysis should be done when designing PCMs in homes, as their thermal performance depends on several variables such as PCM properties and location in the building envelope.

► EnergyPlus PCM model validated using similar approach as ASHRAE Standard 140.
► Analytical verification, comparative testing, and empirical validation.
► Key limitations and guidelines identified when using EnergyPlus PCM model.
► Time steps equal to or shorter than three minutes should be used.
► PCM design requires careful analysis of PCM properties and building location.