Abstract: In the face of the adjustment of global energy structure, it is necessary to take into account the diversified development of energy and efficient energy storage, and energy storage technology plays a very important role in the sustainable development of energy. Phase change energy storage technology has the advantages of high heat storage density, stable heat storage/release temperature, and easy control, and has broad application prospects. In this paper, the development background, working principle and technical characteristics of phase change energy storage technology are introduced, and the research status and history of phase change energy storage heat transfer research are summarized, and the research progress of heat transfer problem in phase change energy storage technology, heat transfer characteristics of phase change energy storage unit and enhanced heat transfer by phase change energy storage unit is summarized.
Conclusions and outlook
To sum up, phase change heat storage technology can realize the storage and rerelease of waste heat and waste heat, solve the contradiction of uncoordinated energy supply and demand time and unbalanced regional distribution of energy, and effectively improve energy utilization efficiency, so phase change energy storage technology has broad application prospects. In the study of phase change heat transfer, numerical and experimental methods are the most widely used research methods, and natural convection has a great influence on the phase change heat transfer process, especially the melting process, which cannot be ignored. Shell-and-tube is the most common phase change storage unit structure [53], which has the advantages of simple structure, convenient manufacturing, and low heat transfer loss. Due to the intensification of natural convection, the horizontal element exhibits better heat transfer performance than the vertical element. In terms of enhanced heat transfer of phase change energy storage units, traditional enhancement methods such as adding high thermal conductivity micro-nano materials, trapezoidal phase change materials, microcapsule encapsulation, fin strengthening, and heat pipe assistance are mainly used.
Although the encapsulated PCM energy storage system has a low PCM volume ratio, a good package system can accommodate the geometric versatility of phase change, so that it can be integrated into any existing system without major technical limitations, while maintaining a larger isothermal phase duration. However, the enhancement of heat transfer between PCMs is a key concern in future packaging systems, as the thermal conductivity of PCMs can be a major issue if a reasonable system heat output is to be achieved.
