Hydrated salts consist of an alloy

Hydrated salts consist of an alloy of inorganic salts and water
and enable a cost-effective PCM due to easy availability and low
cost. The phase change transformation involves hydration or dehydration
of the salts in a process that resembles typical melting and
freezing. The salt hydrate may either melt to a salt hydrate containing
less water or to an anhydrous form where salt and water is
completely separated (Sharma et al. [105]).