Using phase change materials to alleviate overheating phenomenon of residential buildings in severe cold and cold regions of China

Due to global warming, the overheating risk of residential buildings (especially with no air conditioning) in severe cold and cold regions of China is attracting increasing attention. This phenomenon will seriously affect people’s comfort and even health. Fewer studies and Chinese local building standards, however, are related to overheating in such region, which were not considered overheating in the past. It is not clear whether integrating phase change materials (PCM), which has been considered as a useful method to improve thermal comfort, into building envelopes can effectively alleviate the overheating phenomenon in the severe cold and cold regions. This paper aims to reveal the overheating risk by monitoring four residential buildings, and to verify the effectiveness of using PCM to alleviate the overheating in these regions through simulation. The results indicate a significant overheating risk. During the summertime (May to September), overheating hours were recorded for 395, 618, 857 and 713 h out of total 3672 h (accounted for 25.82%, 40.39%, 56.01% and 46.60%) in the south-facing bedrooms of Yichun, Harbin, Shenyang and Dalian respectively. The study finds that PCM reduces overheating hours in south-facing bedrooms in Yichun, Harbin, Shenyang and Dalian by 19.66%, 17.95%, 15.88% and 10.87%, and saves cooling energy by 25.67%, 15.36%, 14.61%, 15.34% respectively. This paper proposes a standard for evaluation and practical guidance for policy makers on reducing indoor overheating in severe cold and cold regions of China.