28. Progress in Sorption Thermal Energy Storage

There are various ways for thermal energy storage, such as sensible, latent, sorption, and chemical reaction. Sensible thermal energy storage and latent thermal energy storage are already in use. However, the drawbacks of bulk size (small energy storage density) and the strict requirement for thermal insulation have hindered their wide applications. Sorption and thermochemical reactions used for thermal energy storage have been considered as a future great potential product for thermal energy storage of solar energy, waste heat. or even electric heating, etc. The market thus needs such a “thermal battery,” which should be with a variety of kWhs capacities. Several key challenges remain in the way of the development of an efficient sorption thermal battery: sorption materials with high storage density and low cost, sorption bed with good heat and mass transfer to ensure charging power and discharging power, being stable after repeated cycles, minimum heat capacity ratio between the inert materials to the sorption thermal energy; control of the output temperature and power to meet the use demand. In this chapter, recent progress in sorption thermal energy storage, including materials, systems, and demonstrations, were described. The detailed future researches and developing maps were also discussed.