Review on tailored phase change behavior of hydrated salt as phase change materials for energy storage

The development of phase change energy storage technology promotes the rational utilization of renewable energy, and the core of this technology is phase change material (PCM). Hydrated salt as PCM is successfully applied in various fields, especially its application in green building attracts the most attention. A suitable phase change temperature and a high latent heat are the basic requirements of PCM, but most hydrated salts cannot fully satisfy these two conditions. Therefore, it is necessary to control the phase transition of the hydrate to have excellent phase change performance. However, there is currently no comprehensive literature on techniques for regulating the phase change temperature and the latent heat of hydrated salt. Based on the situation, this article specifically reviews the methods of controlling the phase change temperature and increasing the latent heat of hydrated salt, aimed to find the foothold and breakthrough point for further study of the optimization of the properties of hydrated salt. Besides, the applications of hydrated salt for thermal and cold energy storage are summarized such as building energy conservation and air-conditioning refrigeration system, which would lay a certain foundation for the development of hydrated salt in the field of energy storage.