Impact of thermal energy storage material on the performance of the adiabatic compressed air energy storage system

초록

Achieving net zero emissions by 2050 requires a transition to clean energy and an expansion of renewable energy usage. Energy storage systems can mitigate the variability of renewable energy and are expected to play a crucial role in this transition. The adiabatic compressed air energy storage (A-CAES) system stores heat and pressure in a thermal energy storage (TES) system and a cavern, respectively, enabling large-scale energy storage with high efficiency. The performance of TES, which stores thermal energy, directly affects the overall performance of the CAES system. The formation and maintenance of a thermocline within the TES is critical to the energy storage efficiency. In this study, a representative packed-bed TES used in A-CAES system was modeled, and the performance of the system was analyzed based on the operational modes (charging, discharging, and standby) and cumulative cycles. This study examined the impact of changes in TES performance on the A-CAES system and analyzed the effects of thermal storage materials and operating conditions. The storage materials considered were rock, aluminum, copper, concrete, and ceramic brick. The performance variations of the A-CAES system were evaluated by comparing the round-trip efficiency (RTE) and the generated energy of the system. Material properties were found to play a critical role in influencing TES behavior, system performance, and the effects of the standby period, particularly in terms of thermal diffusion. Among the materials considered in the simulation, the rock-bed TES exhibited the best performance, generating 586 MWh of energy with an RTE of 0.76. In contrast, the ceramic brick showed the lowest energy output of 409 MWh with an RTE of 0.78, while copper exhibited the lowest RTE of 0.72, generating 549 MWh. This study provides the foundation for understanding the operational characteristics of A-CAES systems under varying TES materials and working conditions, contributing to the development of optimal system design and operation.

키워드