Latent heat thermal energy storage (LHTES) has engrossed augmenting consideration to eliminate the mismatch between energy supply and demand. Latent Heat Thermal Energy Storage has the benefit of greater high-energy densities at nearly constant temperatures among the three thermal energy storage systems.
Thus, the need for energy storage is realized and results in sensible and latent heat energy storage being used. Latent heat energy storage (LHES) offers high storage density and an isothermal condition for a low- to medium-temperature range compared to sensible heat storage.
Latent heat provides substantially high energy storage density and maintains small temperature difference between the storage and release of heat . LHSMs can be of the form Solid–Solid (S–S), Solid–Liquid (S–L), Solid–Gas (S–G) and Liquid–Gas (L–G) based on the transformation type.
Latent heat is measured in terms of a change in enthalpy during phase change. The higher the latent heat of fusion, the lower the amount of PCM; hence, the size of the storage system will be reduced. Solid–liquid phase interaction offers the highest enthalpy of fusion among other possible phase changes .
The latent heat storage (LHS) commonly uses the heat of fusion of melting and solidifying of material, rather than evaporation and condensation, due to the large volume change associated with the latter. The use of phase change materials (PCMs) as base materials for TES increased since the energy crisis in the 1970 s.
Latent heat storage has the higher storage density than conventional sensible heat storage due to high enthalpy change in the phase change process. Compared to the sensible heat storage systems, latent heat storage systems require a smaller weight and volume, which brings about the relatively lower costs.