Thermal performance analysis of multi-phase change material layer-integrated building roofs for energy efficiency in built-environment

Thermal energy storage using phase change materials (PCMs) plays a significant role in maintaining thermal comfort and reducing energy consumption in a building because of its ability to absorb/release heat within small temperature variations. In this paper, the thermal performance of roofs has been investigated based on various factors like the integration of a single PCM layer, integration of a double PCM layer, the thickness of the PCM, phase transition temperature and heat of fusion of the PCM. The analysis shows that integration of a single PCM layer of different thickness and phase transition temperature and heat of fusion in roof structures is unable to maintain a comfortable constant temperature inside the building due to incomplete solidification and melting of the PCM. However, the analysis shows that with multi-PCM layers of appropriate thickness it is possible to maintain a constant comfortable temperature of about 28 °C in the building throughout the day in Chennai, India. The analysis also shows that there is reduction in heat gain by 17 to 26% for a single PCM layered roof and 25 to 36% for a double PCM layered roof compared to the roof without PCM layer for the different months of the year.