Phase change materials for autonomous energy storage in buildings

This research summarizes the findings from a simulation study that explores the potential of using phase change materials (PCMs) when integrated into envelope system of residential buildings. A typical residential building with PCM-embedded layer is analyzed using a whole-building simulation tool "TRNSYS" under two climates of Oman. Although not significant, the simulation study shows that PCM can reduce energy consumption of buildings. The PCM is found to autonomously store and release thermal energy under desirable environmental conditions. The set of simulation runs are found helpful to explore the potential of PCM and the results can be used by architects and engineers to carefully propose PCM in their energy-efficient building designs. It was concluded that the optimal melting temperature of PCM is 1°C above the cooling setpoint in hot-humid climate but found 2- 3°C above or below the setpoint in the warm tropical climate. A tight melting temperature range for PCM was favored. Overall, the PCM poorly performed (i.e., being less than 2% savings in annual cooling load) in a continuously operated dwelling due to the lack of passive means to discharge the absorbed heat. Future research is found crucial to better understand the dynamic thermal behavior of PCM under hot climates. In particular, it will be useful to explore its performance when coupled with natural ventilation.