[Objective] Temperature fluctuations within the underground cavern have a significant effect on the efficiency of compressed air energy storage power stations and the structural safety of the cavern. Installing the heat exchanger inside the cavern is one of the effective methods to suppress air temperature fluctuations. [Methods] A compressed air thermodynamic model that takes into account the heat transfer of internal heat exchangers is established to investigate the effects of different cold and hot water configuration strategies on air temperature and pressure changes inside the cavern. [Results] The results show that by using low-temperature water during the charging phase and high-temperature water during the discharging phase

the internal heat exchanger can effectively suppress the compression heat effect and expansion cooling effect of the air

thereby reducing the range of air temperature fluctuations. Specifically

when cold water(33 ℃) and hot water(90 ℃) are introduced into the heat exchanger during the charging and discharging

respectively

the temperature difference of air can be reduced from 43.9 ℃ without using heat exchangers to below 15.0 ℃. Further analysis indicates that adjusting the cold water utilization period to the latter half of the charging phase and concentrating the hot water utilization time towards the end of the discharging phase can effectively increase the heat transfer temperature difference between the heat exchanger and the air

further reducing the air temperature difference at the end of charging and discharging. [Conclusion] In summary

the reasonable configuration of the operating strategy of the internal heat exchanger

especially the optimization of cold and hot water utilization times

can effectively improve the energy storage capacity and power generation capacity of compressed air energy storage systems.