Investigation of heat transfer of a building wall in the presence of phase change material (PCM)

The energy consumption in buildings for heating, ventilation, and air-conditioning is increasing with the increasing demand for thermal comfort. Thermal energy storage with phase change material (PCM) has attracted growing attention for its role in achieving energy conservation in buildings with thermal comfort. This paper investigates the effect of PCM on the heat transfer rate in a building wall and the role of PCM on the indoor thermal comfort of the building. Two models of building wall fragments were developed for the experimental study. In one model, tests were conducted for different positions of the PCM layer in the building wall to identify the optimal position of the PCM layer inside the wall. In another model, tests were carried out integrating PCM, air gap, and other conventional building materials (brickbat and sand), one at a time, to investigate the role of PCM on the heat transfer rate in the building wall fragment. The results show that placing the PCM layer closer to the heat source gives a low-temperature gain of the cold water bath (indoor state) as compared with the PCM layer near the heat sink. With PCM, the temperature rise of the cold water bath (indoor state) of the building wall fragment was the lowest, and the slope of the temperature rise of the cold water bath becomes steadier with time i.e., fewer temperature fluctuations. There was a significant time delay for the cold water bath to reach a given temperature. The heat required for a unit degree increase in the temperature of the cold water bath was higher and the peak heat flux of the wall was lower relative to the other building materials.