Enhance of Expanded Graphite in Double Layer Phase Change Walls on the Temperature and Energy Consumption

Abstract

Over the past few decades, phase change materials (PCMs) have been used widely in buildings energy consumption due to their excellent performance. The combination of PCM and wall into a composite structure is also a commonly used method. In this paper, a new kind of double layer phase change wall with expanded graphite (EG) is studied. By adding EG, the time needed for phase change process is shortened and the time for the wall to work is accelerated. A data acquisition instrument was used to measure the temperature change process. The results show that the double layer phase change wall with EG can suppress the temperature value fluctuation. Based on the climatic conditions in Shanghai, we simulated the cooling and heating loads with or without phase change walls. The results show that the loads are reduced by more than 15%. The simulated values are consistent with the experimental values, and the temperature deviation at the same point in the same period is small. The maximum temperature change between the experimental and simulated values is less than 1 ℃. The double layer phase change wall with EG can reduce the temperature difference and improve the indoor thermal comfort.