Development and Application of a Laboratory Simulation Device for the Underground Compressed Air Energy Storage System

The compressed air energy storage (CAES) in the underground lined rock cavern is a promising long-term energy storage technology, while the mechanical and temperature responses during the cyclic process of gas charging and discharging are highly complicated. Current research on the mechanical and thermodynamic properties of CAES caverns primarily relies on field tests and numerical simulations. However, field tests are prohibitively expensive and difficult to replicate, while the reliability of numerical simulations remains questionable. To address these limitations, this study presents a novel laboratory simulation device, which is capable of replicating the coupled thermo-mechanical (T-M) conditions of underground CAES caverns, including geostresses up to 100 MPa, temperatures up to 300 °C, and cyclic gas pressures of 0-70 MPa. The integrated system combines a geological environment simulation system, a gas pressure control system, and a measurement system. Experimental validation using a 300 mm × 300 mm × 300 mm lined rock cavern sample (butyl rubber sealing and C40 concrete lining) under 8 MPa geo-stress and cyclic pressure (1.5-7.1 MPa) revealed three key findings: (1) creep behavior and irreversible strain accumulation in the sealing layer, (2) strong relationship between internal pressure and gas leakage rates, and (3) quantified temperature gradient evolution in sealing and lining layers (<i>R</i> ² = 0.997 for thermal decay profiles). Meanwhile, results showed that all three systems worked smoothly. The device provides a unique platform for investigating multifield coupling effects in CAES, offering critical insights for design optimization and reliability enhancement in renewable energy storage systems.