Thermodynamic Analysis and Performance Evaluation of a Multi-stage Compressed Air Energy Storage System for Renewable Energy Grid Connection

Renewable energy power generation is highly influenced by weather conditions, and grid connection is characterized by strong intermittency. Compressed air energy storage (CAES) technology provides an effective solution to the grid connection challenges in large-scale power generation scenarios. This study addresses energy conversion issues by analyzing a five-stage compression and three-stage expansion CAES system. Thermodynamic models were established for key components such as compressors, turbines, and heat exchangers. Using Simulink, the CAES system was simulated to analyze its operational characteristics under ambient air inlet conditions (25 ℃). Simulation results indicate that the multi-stage compression-expansion CAES system achieves a balance between energy storage and release, with the compressed air storage tank pressure stabilizing at 10 MPa and a temperature rise of only 3 ℃. Additionally, the residual heat from the compression process is utilized to heat the compressed air entering the turbine, thereby improving power generation efficiency. This study provides an in-depth analysis of the application of multi-stage CAES systems in the efficient and stable conversion of renewable energy, offering significant guidance for their engineering applications and system design.