## 1 Introduction  
Large scale energy storage systems are required to facilitate the penetration of variable renewable energies in the electricity grids [1, 2, 3, 4]. Underground space from abandoned mines can be used as underground reservoirs for underground pumped storage hydropower (UPSH) and compressed air energy storage (CAES) systems [5, 6, 7, 8, 9, 10, 11]. Pumped storage hydropower (PSH) is the most mature large-scale energy storage technology, and the round trip efficiency is typically in the range of 70-80% [12, 13]. Diabatic CAES (D-CAES) is an alternative to PSH that requires lower capital costs and the round trip energy efficiency is around 40-50% [14]. D-CAES systems use natural gas to heat the compressed air in the decompression period. However, Adiabatic CAES (A-CAES) allows the storage of the thermal energy during the air compression period, avoiding the consumption of natural gas, therefore increasing the round trip energy efficiency up to 70-75% [15, 16, 17]. During the operation of A-CAES plants, the air is stored in the underground reservoir at high pressures during the charge period. Then, in the discharge period, the pressurized air is released, heated (stored heat), and expanded to generate electricity as the pressure within the reservoir is reduced. During the storage period, between charging and discharging, the air pressure and temperature vary depending on the storage time. The amount of stored energy depends on the reservoir volume and the thermodynamic conditions. The air temperature variations depend on the thermal conductivity of the sealing layer, concrete lining and rock mass. Therefore, the air temperature and pressure fluctuations are essential to design the reservoir volume, to select the appropriate compressor and turbines and to ensure safe operating conditions. [PERSON] et al. [18] developed a study to determine the temperature and pressure variations within compressed air energy storage caverns and showed that the heat transfer reduces the temperature and pressure variations during the compression and decompression periods, leading to a higher storage capacity. Thermodynamic models were performed to determine temperature and pressure variations within adiabatic caverns of compressed air energy storage plants [19]. The results showed that the storage volume is highly dependent on the air maximum to minimum pressure ratio. [PERSON] and [PERSON] [20] carried out a thermodynamic analysis of three compressed air energy storage systems. They concluded that A-CAES with physical heat storage is the most efficient option with an exergy efficiency of 69.5%. A pilot-scale demonstration of A-CAES was built in Switzerland [21; 22]. The cavern was 120 m long and 4.9 m in diameter with a usable volume of 1942 m\({}^{3}\). A packed-bed of rocks for thermal energy storage was located inside the cavern. Charging temperatures of 550 \({}^{\circ}\)C and air pressures between 0 and 0.7 MPa were employed in the test and constant heat transfer coefficients of 5 and 10 W m\({}^{-2}\) K\({}^{-1}\) were considered in the simulations. The estimated round trip efficiency of the pilot plant reached 63-74%. [PERSON] et al. [23] analyzed the effect of the cyclic loading on the geomechanical performance of CAES systems for lined and unlined tunnels in closed mines. The cycling loading operation was simulated for 10,000 cycles considering an operating pressure within the reservoir from 4.5 to 7.5 MPa. They observed moderate deformations and small thickness of plastic zones, while an increase of the initial volume of less than 0.5% was reached. [PERSON] et al. [24] carried out experimental and numerical investigations of a lined rock cavern to analyze the thermodynamic process within the underground cavern. The volume of the cavern was 28.8 m\({}^{3}\) with 5 m length and 2.9 m in diameter. A 2 cm thick RFP was employed as sealing layer around the compressed air. The air pressure reached 6 MPa at constant mass flow rate (0.12 kg s\({}^{-1}\)). [PERSON] et al.