Comprehensive exergy analysis of the dynamic process of compressed air energy storage system with low-temperature thermal energy storage

Compressed air energy storage (CAES) system with low-temperature thermal energy storage (TES) has advantages of profitability and start-up characteristics in the field of electrical energy storage, and many CAES pilot plants have been built in China. However, CAES systems face challenge of different working conditions in operation process due to changing pressure of air storage, influence of components’ thermal mass and other boundary conditions. In this paper, we simulated a dynamic CAES system in which part-load operation regularities of compressors and expanders, thermal inertia of components, volumetric effects of pipes and heat exchange between system and environment were taken into consideration. Based on this, exergy analysis of whole energy storage process and influence of ambient factors on multi-cycle performances have been conducted. The results indicate detailed features of the dynamic charging and discharging processes including system performance at start-up stage and entire process, which are beneficial to a comprehensive understanding of operation process and can be a reference in design and operation of CAES plants.