16 - Phase change materials for energy storage and thermal comfort in buildings

Abstract

This chapter reports on recent research conducted on the use of phase change materials (PCM) for thermal comfort and heating and cooling peak load shifting in buildings. The objective here is to show experimentally and through a computer simulation that PCM impregnated in building materials can provide thermal energy storage benefits. Paraffin (RT20) has been used as the PCM because of its desirable thermal and physical attributes including its melting temperature of 20–22°C, which is close to human comfort temperature. The PCM was impregnated into gypsum wallboards to produce an efficient thermal storage medium (PCMGW), which consists of 26%-wt PCM impregnated in gypsum boards. This PCM-gypsum wallboard structure was tested in-situ in an office size building. In parallel, a thermal building simulation code (SUNREL) was used to simulate the performance of the office size rooms. Measured and simulated results in summer showed that the use of PCMGW effectively reduced diurnal daily fluctuations of indoor air temperatures and maintained the indoor temperature at the desired comfort level for a longer period of time. A major benefit of thermal energy storage in winter is to reduce electricity demand charges by limiting the need to run electrically operated heating and air-conditioning devices during peak load periods. This study reveals that this application of PCM storage in buildings can lead to healthier interior spaces, and more efficient energy use in terms of demand charge reduction and use of favourable off-peak rates.