Comprehensive assessment of PCM integrated roof for passive building design: A study in energo-economics

There has been a notable surge in energy demand within the building sector of developing nations, particularly in the context of space cooling and heating, which constitute significant portions of energy consumption. The thermal performance of a building's roof slab plays a crucial role in determining these heating and cooling requirements. To address this, the utilization of Phase Change Material (PCM) to enhance the building's thermal energy storage capacity has emerged as an innovative strategy for reducing energy demand. This study assesses the thermal behavior of a building envelope integrated with macroencapsulated PCM in a real subtropical environment. Experimental setups include both a conventional slab unit (Ref–SU) devoid of PCM and a PCM (OM37) integrated slab unit (Exp–SU). Analysis entails examining variations in temperature, heat flow, thermal loadings, and maximum heat gain reduction. Economic metrics, such as electricity savings, simple payback periods, and CO₂ emissions savings, are also scrutinized. The investigation aims to elucidate the efficacy and underlying parameters governing the PCM's performance in reducing thermal loads in the Indian city of Rupnagar. Findings indicate that the Exp–SU configuration reduces indoor temperatures by 4.0 °C during sunny hours, resulting in 33.33 % more electricity savings for space cooling compared to heating, with a simple payback period of 5.7 years. Additionally, the heat flux in Exp–SU is reduced by 60.6 % compared to Ref–SU and thermal load by up to 49.8 %. Furthermore, Exp–SU achieves a 44.24 % reduction in CO₂ emissions for space cooling compared to heating with a maximum heat gain reduction of 40.3 %.