In the current energy transition, abandoned mines can be used as strategic large scale energy storage systems. Lined mining drifts can store compressed air at high pressure in compressed air energy storage systems. In this paper, three-dimensional CFD numerical models have been conducted to investigate the thermodynamic performance of underground reservoirs in compressed air energy storage systems at operating pressures from 6 to 10 MPa. U-shaped mining drifts with a cross-sectional area of 8 m2 and a volume of 400 m3 have been selected as underground reservoir. A 15 cm thick reinforced concrete lining and a 5 m thick rock mass have been considered around the compressed air. Air temperature and pressure variations within the reservoir and heat transfer across the reservoir walls were analyzed for ten compression and expansion cycles considering different operating conditions. Then, the results of the numerical model were used to estimate the preliminary energy balance and the round-trip energy efficiency. To validate the results of the numerical model, a one-dimensional analytical model has been developed. The results obtained show that the power generation and the round-trip energy efficiency increase when the variations in air temperature are reduced. A 4.60% increase in power generation was observed in the expansion process when the air mass flow rate is reduced from 150 to 50 kg s− 1. The round-trip efficiency reaches 0.71 for an A-CAES scheme with air mass flow rates of 25 and 50 kg s− 1 in compression and expansion, respectively. Finally, good agreements have been obtained between analytical and numerical results.