Preferred method and performance evaluation of heterogeneous composite phase change material (CPCM) wallboard in different seasons

The application of phase change materials (PCMs) in building envelopes has been developed in past decades and many strategies have been adopted to improve the heat resistance and capacity performance. However, rare studies focused on optimizing these characteristics of PCM wallboard in different seasons and providing preferred method for selecting the optimal PCMs. This study constructed a heterogeneous wall acting in different seasons and developed a pre-screening method of PCMs based on the analytic hierarchy process. CA-HD/EG with higher thermal conductivity (2.16 W/(m·K)) and lower melting point (25.4 °C) acted as the inner layer, and paraffin/porous silica with lower thermal conductivity (0.37 W/(m·K)) and higher melting point (29.3 °C) acted as the outer layer. Two experimental boxes were built to compare the thermal performance of CPCM and gypsum wallboard. The decrement factor in winter increased by 6.7 %, and the heat storage coefficient in summer increased by 0.97. The thermal comfort duration in winter was extended by 17.9 %, and the thermal load leveling in summer was reduced by 11.5 %. The heating/cooling water supply duration was shortened by 2.5 h, resulting in an energy-saving rate of 13.3 %. Consequently, the CPCM wallboard maintained a better indoor thermal environment with a lower energy consumption.