Sorption Thermal Energy Storage: Concept, Progress and Prospects

摘要

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 and etc.. The market thus needs such a "thermal battery", which should be with a variety of kWhs capacities (1, 10, 100, 1000 or even more). Several key problems remain to be solved for an efficient thermal battery: sorption working pairs in which sorption materials should have high sorption capacity, low generation temperature, and low cost; good design of a sorption bed, in which the sorption bed should be capable of 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, which is critical for real applications; potential served as a heat transformer. In this paper, all these aspects related to sorption thermal energy storage concept, including materials, systems and demonstrations, were described. The detailed future researches and developing maps were also discussed.