Review on thermal performances and applications of thermal energy storage systems with inorganic phase change materials

For solving the global problems of environmental pollution and energy shortages, thermal energy storage system that can improve the efficiency and utilization ratio of energy and solve the gap between energy demand and supply, has received more attention in recent years. More specifically, the latent thermal storage systems that use phase change materials (PCMs) as storage media, possessing high latent heat storage density and almost constant phase change temperature are the focus area in thermal energy storage. Previously, most of the researches on PCMs were organic, however in recent years, inorganic PCMs with large phase change temperature range have been paid more and more attention. In common inorganic PCMs, hydrated salts possess lower phase change temperature, applying in buildings, solar water heating systems, textiles, etc., and molten salts and metals have higher phase change temperature, applying in concentrated solar power (CSP) generation and industrial waste heat recovery etc. Each has its own outstanding merits, for example, inorganic salts possess a large latent heat storage capacity and metals possess an extremely high thermal conductivity. Therefore, this review focuses on the researches of inorganic PCMs in recent years and summaries their thermal properties, and introduces the integration of inorganic PCMs into heat exchangers and some applications of inorganic PCMs in main systems, seeking to give readers a relatively comprehensive awareness on them.