Progress and challenges of latent thermal energy storage through external field-dependent heat transfer enhancement methods

The development of Energy Storage technologies is critical to achieving a cleaner energy future. As one of the most widely used energy storage technologies, Latent Thermal Energy Storage (LTES) still suffers from poor charging and discharging performance subjected to the low thermal conductivity of Phase Change Materials (PCMs) and inefficient heat transfer process. Heat transfer enhancement techniques, such as using fins and adding highly conductive materials, have been widely developed and optimized to overcome these challenges. Recently, additional novel methods integrating adjustable external fields such as gravity, magnetic field, and electric field have been proposed to enhance the heat transfer performance of LTES, due to their advantages including easy adjustment of the field parameters according to the evolution of the heat storage process. Firstly, this work briefly summarizes the progress of conventional heat transfer enhancement methods. Secondly, the advancement of heat transfer enhancement by integrating adjustable external field effects has been analyzed and discussed. Finally, the potential of external fields to improve the heat storage performance of LTES under fluctuating thermal sources is discussed considering the wide existence of fluctuating energy supply and load in real applications. The main contributions from this review are: (a) The emerging heat transfer enhancement methods for LTES are comprehensively summarized and discussed for the first time; (b) The potential of different heat transfer enhancement techniques is demonstrated to overcome the poor heat storage performance under fluctuating thermal sources when considering real applications of LTES.