Optimization of thermochemical energy storage systems based on hydrated salts: A review

Thermochemical energy storage (TCES) based on the use of hydrated salts holds great promise for building space heating and domestic hot water production. However, it faces technical challenges such as poor heat and mass transfer and poor cycle stability, which hinder its commercialization and widespread practical application. Given that these challenges can be addressed by optimization measures, this review summarizes the latest progress in TCES system optimization, focusing on the optimization of composite sorbents, reactors, and prototype systems. For composite sorbents, this paper elaborates on the properties of common matrix materials and proposes the types of hydrated salts suitable for pairing according to different matrix materials. For different types of reactors, the advantages and disadvantages of each type of reactor are analyzed, and the structural optimization methods and design optimization methods for enhanced heat and mass transfer are summarized. Regarding prototype systems level, three aspects of cyclic process optimization, operation optimization, and coupling system optimization are summarized respectively. It is expected that the data presented will help researchers and designers gain a more comprehensive and profound understanding of TCES systems as a whole and provide ideas and guidance for their further optimization to improve overall performance.