Study on the dynamic characteristics of adsorption-type compressed CO₂ energy storage system: Based on the cycle self-consistent regulation mechanism of high-pressure storage tank

To address the engineering challenge that the cycle of a compressed gas energy storage (CGES) system cannot form a closed loop, this paper proposes an innovative active regulation mechanism to realize the cycle self-consistency of a high-pressure storage tank (HPT). Based on this mechanism, 108 feasible HPT cycle self-consistent schemes are identified through simulation within the defined operational domain. One representative scheme—featuring an HPT initial temperature of 308.15 K, a gas source temperature of 290.15 K, and a make-up heat power of 539 kW—is selected for detailed analysis. Under this scheme, the HPT undergoes phase transitions through gas, gas-liquid coexistence, liquid, and supercritical phases during inflation, and transforms directly from the supercritical to the gas phase during deflation. The mechanism achieves cycle self-consistency by actively regulating the HPT's thermodynamic state through coordinated adjustment of initial temperature, gas source temperature, and supplemental heat input, ensuring that the start and end states of each cycle coincide. Furthermore, the dynamic operational characteristics of a modified temperature swing adsorption-based compressed CO₂ energy storage (TSA-CCES) system are investigated. The system achieves a round-trip efficiency of 93.18%, an energy storage density of 6.49 kWh/m³, an effective gas storage density of 500 kg/m³, and a tank utilization rate of 72.95% under the selected scheme. Compared to previous studies, the proposed system achieves over 50 times higher effective gas storage density, and a tank utilization rate more than 10% higher than existing schemes, demonstrating that the proposed mechanism ensures a self-consistent HPT cycle while significantly improving system performance and robustness, offering practical guidance for the engineering application of CGES systems.