Analysis of design parameters of Phase Change Material Boards (PCMBs) for reconstruction of lightweight building exterior wall

Abstract

Installing phase change material boards (PCMBs) on existing buildings is regarded as an effective and economical approach to reduce the high energy consumption of buildings. In this paper, the thermal performance of PCMB under summer conditions are numerically studied, and the optimal thickness of PCMB for traditional brick-concrete exterior wall is theoretically analyzed. Unlike the constant room temperature used in other studies, this study employs a small range of sinusoidal fluctuations in room temperature. An improved evaluation parameter, Energy Saving Potential (ESP), derived from the variation of inner surface temperature of the PCMB, is introduced to evaluate the factors affecting its thermal performance. The results indicate that when the phase change temperature falls within the range of indoor air temperature, the narrower the phase change temperature, the higher the ESP. When the phase change range is 3 °C, the ESP value decreases by 3.7 % compared to the single phase transition temperature. In addition, higher latent heat of phase transition and lower thermal conductivity result in higher ESP. For the thermally optimized PCMB, a thickness of 10 mm can effectively maintain indoor thermal comfort and achieve energy saving. The purpose of this study is to optimize the thermophysical properties and thickness of PCMB by combining numerical and theoretical analysis, so as to provide support for the design and manufacture of the PCMBs.