Design of composite materials/devices for thermal storage – A critical review

Energy storage plays a critical role in facilitating penetration of renewable energy and reducing carbon emission of conventional energy system. Among various energy storage technologies, thermal storage allows energy to be stored in form of heat or cold so that it can be used, later on, for heating and cooling purposes as well as for power generation. Development of highly efficient and cost-effective thermal storage materials as well as the corresponding devices has attracted much attention. Composite materials based on latent heat storage (LHS) have shown great potential for many thermal storage applications. This paper firstly elaborates the recent progress in the study of micro-structured LHS composite materials in light of three different types of material synthesis methods including incorporation, impregnation and microencapsulation. Detailed discussions about morphology, performance enhancement of thermal storage and heat transfer, and various applications are carried out for current micro-structured LHS composite materials. The latest study progress in macro-structured LHS devices are then summarized, which includes the structural design of devices, optimization of heat transfer and device efficiency, as well as the performance of the devices with different storage media. Lastly, opportunities for future work are identified.