Experimental study on thermal characteristics of a dual-effect shape-stabilized PCM slab for both winter and summer applications

Sky radiation cooling and solar radiation heat can serve as effective cold and heat sources for regulating the thermal environment of buildings. By actively or passively integrating phase change material (PCM) walls, the challenges posed by intermittent and unstable energy supply can be effectively addressed. However, conventional single-layer PCM walls typically have only one phase-change temperature, making them effective for only a specific season (i.e., summer or winter), which limits their annual energy efficiency. This study proposes a dual-effect shape-stabilized PCM (D-SSPCM) slab, which is developed by uniformly mixing two types of shape-stabilized PCMs with different phase-change temperatures. This D-SSPCM slab may possess both high and low phase-change temperatures adapting for the environmental characteristics of both summer and winter. To investigate its thermal characteristics, the D-SSPCM was developed first. Then, it was molded into slab and the dynamic thermal characteristics of the melting and solidification processes were tested under specified boundary conditions. The numerical model was validated by experimental results, and the thermal performance of the D-SSPCM wall was analyzed using the simulations. The results indicate that the D-SSPCM slab exhibits two phase-change intervals during both melting and solidification processes. The melting process occurs at 23.6–27.5 °C and 29.1–30.2 °C, while the solidification process occurs at 22.3–24.9 °C and 26.9–30.2 °C. This research effectively validates the dual-effect phase-change characteristics of the D-SSPCM slab and its excellent peak load shaving performance.