Sorption thermal energy storage

Abstract

Sorption thermal energy storage (STES) technology is a promising thermal energy storage method which many scholars hold avid interest on recently as it has charming advantages of high energy storage density and negligible heat loss during storage periods. This system is suitable to supply space heating and hot water for buildings by storing solar energy or other low-grade heat. The working cycle of this system is divided into two modes, which are listed as follows. During the charging process, the input heat is stored in the form of chemical potential by breaking the binders between the sorbate and the sorbent. Then, the sorbate and the sorbent are kept separated during the sorption period. The discharging process is motivated by the connection between the sorbent and the sorbate, which release sorption heat for heating supply when needed. Generally, the sorption materials are composed of solid adsorbent, liquid absorbent, chemical reactor, and composite sorbents. The STES system is classified as closed system and open system according to its configuration. Besides, it can also be divided into long-term storage system and short-term storage system based on the designed storage time span. Thermochemical characterizations of sorption materials, system design, and proposal of system cycles serve as the main aspects of the investigation of STES technology. In this chapter, the high-end STES technology of solar energy storage, which is applied in buildings, is concluded, including the sorption energy storage mechanics, sorption materials, system design, as well as typical prototypes and projects.