Key technologies and research progress on enhanced characteristics of cold thermal energy storage

Cold thermal energy storage can be used to address the unbalanced distribution of electrical energy temporally and spatially by using phase change materials (PCMs). However, these materials face multiple disadvantages, such as phase separation, supercooling, poor heat-conducting performance, etc. Previous literature has revealed that the main approaches to address such issues include material modification, the outfield effect, and heat exchange structure enhancement. Since the 1990s, pulsating heat pipes have been considered a new type of heat exchange structure due to several advantages, including efficient heat transfer and high heat flux. Nanoadditives have proven to effectively improve the heat conductivity coefficient of PCMs, while ultrasonic waves have shown to induce nucleation and improve the homogeneity of heat and mass transfer. The application of pulsating heat pipes into phase change material-based cold energy storage, coupled with ultrasonic waves, appears to be promising as an effective measure to increase the performance of cold thermal energy storage. (C) 2019 Elsevier B.V. All rights reserved.