A review of salt hydrate-based sorption technologies for long-term thermal energy storage

Abstract

Thermochemical heat storage appears to be an attractive alternative solution for long-term heat storage, as it offers large energy capacity and negligible heat loss during long-term storage. Salt hydrate-based sorption is a typical thermochemical heat storage technology, and has become a new research hotpot for long-term thermal storage. It is featured by combined beneficial parameters such as low cost, benign environmental impact, high energy density, and safety operation. In this paper, the advances in the salt hydrate-based sorption technology for long-term heat storage are comprehensively reviewed. Special attentions are paid on the research of sorption properties of pure hydrate salts and composite materials, thermal performance of various sorption reactors, numerical investigation and performance evaluation of the sorption reactor and the whole thermochemical storage system. Finally, based on the understanding of the state of the art, characteristics of the salt hydrates-based seasonal thermochemical storage technology are summarized and the future research directions are discussed.