Abstract: Hydrated salt-based phase change materials have several advantages including moderate phase transition temperatures, high thermal conductivity, high latent heat and low prices, and hence a potential for a broad range of applications. Such materials, however, often come across problems including supercooling, phase separation and poor cycling stability, which limit their practical applications. One way to resolve the problems are the combination of the hydrated salts with other materials to form composites. This has been proven highly effective. Recent years also see researchers to use composite phase change materials as a mean to improve thermal properties of the phase change materials, including phase transition temperature, thermal conductivity and latent heat etc. This paper summaries recent progress in the area.

Key words: hydrated salt, composite phase change material, supercooling, phase separation, cycling stability, thermal properties