Enhancing thermal comfort in buildings through the integration of phase change material on the building envelope: a simulation study

Abstract According to the report published by the International Energy Agency (IEA), active space cooling and air conditioning systems consume approximately 16% of the building sector’s final electricity consumption and contribute 3.94% of global greenhouse gas emissions. In this regard, the use of low-cost but effective passive solutions, such as organic phase change materials (PCM) on the building envelope, can provide high thermal mass and thus can lower the temperature fluctuation inside the building. In the current study, the potential of PCM-enhanced building envelopes to enhance thermal comfort has been studied. The study has been performed using the conduction finite difference (ConFD) algorithm in EnergyPlus software. A comparative study has been done for a traditional reinforced cement concrete (RCC) reference test room of size (5m x 6m x 3m) and another room of the same size with PCM-enhanced walls for the hot and humid climate zone of Guwahati (latitude 26.1, longitude 91.7), in India. A PCM thickness of 20 mm is used at the external surface of the wall between the red clay burnt brick (120 mm in thickness) and the cement plaster (25mm thick). The PCM used for the study is a biocomposite PCM, named WH-PCM, with a melting point of 31.5°C and thermal conductivity of 0.27 W/mK. The simulation results reveal that the R-value of the external wall of the room with PCM walls has been increased by 84.90% compared to the reference room with the incorporation of WH-PCM, resulting in a mean zone temperature difference of 0.3°C throughout the year. Also, the indoor thermal discomfort hours have been annually reduced by 15.82% with the use of WH-PCM when compared with the reference room. A similar temperature difference trend, which is 1.93°C, is also observed in the single PCM brick experimental result under identical testing conditions as a regular brick of the same size.