Phase Change Materials (PCMs) and Their Optimum Position in Building Walls

Abstract

More than half of the energy consumption in buildings is utilized for the heating and/or cooling of the indoor environment. The building envelope plays a key role in controlling the effects of external weather and, therefore, is linked with many passive design strategies. Thermal energy storage (TES) and phase change materials (PCMs) are efficient techniques, which can store a high density of thermal energy. The PCMs attract many researchers to implement them in the components of buildings for thermal management. In building walls, they were implemented in different positions and have achieved different results. This paper aims to review the related literature that examines PCMs’ application in different positions within the building walls to locate their optimum position and the influential parameters. It was found that the optimum positions of PCMs are highly dependent on performing a daily complete melting/freezing cycle to be ready for the following day. Many parameters can influence this, including climate and weather conditions and the application target, PCMs’ melting temperature and heat of fusion, PCMs’ amount, the thermal properties of the wall’s materials, a mechanical heating/cooling or free-running indoor environment, and wall orientation. An optimization process using the simulation tools is suggested so that the optimum position of the PCMs can be located.