Use of Phase Change Materials for Thermal Comfort and Electrical Energy Peak Load Shifting: Experimental Investigations

This paper reports on recent research conducted on the use of phase change materials (PCM) for thermal comfort and peak load shifting. Its objective is to show theoretically and experimentally 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 the human comfort temperature. The PCM was impregnated into gypsum wallboards to produce a significant thermal storage medium (PCMGW), which consists of 26%-wt PCM. This structure of the PCM-gypsum wallboard (PCMGW) was tested in-situ office size huts, specifically designed for this project. In parallel, a thermal building simulation code, using SUNREL software, was used to simulate the performance of the huts. 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 electrical demand charges by limiting the need to run electrically operated heating 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.