Review on Heat Transfer Enhancement Methods of Latent Heat Storage Technology;Key Laboratory of Refrigeration and Cryogenic Technology of Zhejiang Province

Abstract

Latent heat storage (LHS) technology can solve the time-space non-continuity in the transfer of thermal energy, which can effectively reduce heat loss and accelerate the realization of China's carbon neutrality goal. However, the LHS system in practical applications needs to be equipped with heat transfer enhancement devices, considering the low thermal conductivity of phase change materials (PCMs), which significantly increases the system complexity and capital cost. In this review, heat transfer enhancement methods, namely single heat transfer enhancement technology, combined heat transfer enhancement technology, multi-stage heat transfer enhancement technology, and liquid PCM flow enhancement technology, are briefly classified. The corresponding shortcomings of the last three technologies are described and explained. Based on the obtained conclusions, three relative geometric relations between the heat source and heat sink are summarized, namely the expansion type, parallel type, and contraction type, which can effectively guide the overall design of the latent heat storage units. Finally, the future application prospectives of latent heat storage technology are discussed. It is necessary to design latent heat storage from the system level based on knowledge of thermodynamics and system theory to achieve optimal thermodynamic performance and economic efficiency.

Keywords

• phase change
• convection
• heat transfer
• enhancement
• heat storage