Simulation and Dynamic Analysis of Small Advanced Insulated Compressed Air Energy Storage System

[Objective] Small-scale compressed air energy storage systems are independent of specific geographic environments, have broad applicability, low construction and operating costs, and are suitable for distributed energy systems and microgrid applications. They offer continuous, stable power security for remote areas, islands, or temporary facilities. To enhance the efficiency of a small-scale compressed air energy storage system, the article analyzes the impact of operating the system under various conditions on its performance. [Method] A static model and a dynamic model of a small advanced compressed air energy storage system were established. Taking the 10 kW class energy storage system as a case study, the impact of compressor inlet temperature, compressor total pressure ratio, and the number of expansion stages on the thermal performance of the system was analyzed. Additionally, the dynamic variations in temperature and pressure of the storage tank were simulated based on Matlab simulation software. [Result] The results indicate that although higher compressor inlet temperature and overall pressure ratio reduce the energy storage efficiency of the system, they increase the energy storage density. The post-throttling pressure (inlet pressure of the expansion section) affects the energy storage density. Under design conditions, when the post-throttling pressure is 1.35 MPa, the energy storage density reaches a maximum value of 8.15 MJ/m3. When the energy storage pressure increases from 3 MPa to 6 MPa, the system's energy storage efficiency increases by 9.02%, and the energy storage density grows by 1.72 times. With increased heat exchange between the gas storage tank and the environment, the energy storage efficiency initially decreases and then increases. When the heat transfer coefficient is 5 W/m2/K, the system's energy storage efficiency reaches a minimum value of 45.98%. [Conclusion] For small adiabatic compressed air energy storage systems, increasing the storage pressure of the tanks and improving the heat exchange between the tanks and the environment can effectively enhance the energy storage density of the system. These findings offer valuable insights for the design and optimization of such systems.