Because we spend most of our time in enclosed spaces, thermal comfort of buildings rose increasinglyand then energy consumption correspondingly is increased, aggravating the pollution of naturalenvironment. Integrating phase change materials (PCM) into building walls is a potential method ofreducing energy consumption in passively designed buildings. However, there is a strong need forexperimental data to evaluate the capacity of PCM to stabilize the internal environment when there areexternal temperature changes and solar radiations: that is the purpose of our article.