Review on the recent progress of thermochemical materials and processes for solar thermal energy storage and industrial waste heat recovery

Abstract

Thermochemical heat storage (THS) systems have major advantages over other thermal storage systems, notably high energy density and low heat loss when hermetically sealed. There are several review papers available that discuss THS. Unlike other published review articles, this paper presents a literature survey and a review that add insights into the current state-of-the-art THS technologies, covering: the THS materials, THS reactor design and THS as thermal batteries. Emphasis is placed on THS for solar thermal energy storage and also for industrial waste heat recovery. At the materials level, in addition to a review on THS material sorbents, emphasis is placed on innovative composite THS materials with salt mixtures and metal-organic frameworks materials. Reactor design is one of the major fields of THS system development. In this paper, we also review several types of innovative reactor designs, including hybrid THS systems, towards obtaining advanced reactor concept, numerical studies in THS studies mainly covering the heat and mass transfer in the reactor designs, and also the implementation of THS systems as thermal batteries. Among the main conclusions, it is found that, although several advancements have been achieved in these fields in the last decade, further research is needed for advancing THS technology to be commercially viable. This paper will provide a wide range of information including the research gaps and critical issues in this field. The authors aim to allow readers to identify gaps/issues in the current research towards improving the practicality of THS systems.