A review of heat transfer performance enhancement and applications of inorganic salt based shape-stabilized composite phase change materials for medium and high temperature thermal energy storage

The large-scale utilization of inorganic salts as promising candidate for medium and high temperature thermal energy storage has been significantly restricted at both industrial and commercial scales due to the two main limitations of low thermal conductivity and chemical incompatibility. Recent researchers have revealed that the development of shape-stabilized composite phase change materials (CPCMs) could provide an effective solution to overcome these challenges. Such CPCMs are consisted of an inorganic salt for energy storage, a skeleton structure material for shape stabilization and a thermal conductivity enhancement additive for heat transfer enhancement, and has shown to achieve an excellent combination of thermophysical and mechanical properties. In this paper, a comprehensive review of such shape stability salt based composite in state of the art is presented. The selection principles and criteria for the ingredients of inorganic salts, structural materials and thermal conductivity enhancers that suitable for fabricating composite is first reviewed. And then, the key research progresses on the composite heat transfer investigation and performance enhancement are summarized and discussed. Furthermore, the applications of this inorganic salt based composite in the fields of medium and high temperature thermal energy storage are reviewed in detail. Finally, the limitations and future considerations as well as research direction on such composites are highlighted.