Building envelope-combined phase change material and thermal insulation for energy-effective buildings during harsh summer: Simulation-based analysis

Combined phase change material (PCM) and thermal insulation is a crucial practical opportunity to improve thermal inertia and resistance for energy-effective and nearly-zero energy buildings. To this aim, the current paper quantitatively investigated the role of traditional expanded polystyrene (EPS) thermal insulation of different thicknesses to improve the thermal performance of building envelope integrated PCM under harsh summer months. The improvement in indoor temperature was studied considering the maximum indoor temperature reduction (MITR), time lag (TL), average temperature fluctuation reduction (ATFR) and average operative temperature reduction (AOTR). Thereafter, the average heat gain reduction (AHGR) was introduced to quantify the thermal enhancement of envelope elements. Simulation results revealed that building envelope integrated with PCM-EPS demonstrated better thermal performance than incorporating PCM alone. Compared with the PCM room, the indoor temperature of PCM-EPS rooms was improved by a maximum of 143 %, 177.2 %, 35 % and 8.5 % in terms of MITR, TL, ATFR and AOTR, respectively, along with enhanced envelope resistance by up to 103.8 % concerning the AHGR. Increasing EPS layer thickness by up to 2 cm has increased the PCM room thermal performance during the daytime. However, the EPS thickness of 1 cm showed better performance considering the ATFR and AOTR during full thermal cycles.