一种压缩空气与抽水蓄能耦合的新型储能系统及热力学分析

The subject in this paper is a new energy storage system coupled with compressed air and pumped-hydro energy storage, including the compressed air energy storage (CAES) part and pumped-hydro compressed air (PHCA) part. With this new energy storage system, graded utilization of pressure energy could be realized, and the operating conditions of the two parts could be improved. It has high electricity-electricity conversion efficiency, and provides new ways for the utilization of shallow waste tunnels and caves. For its structural characteristics, we performed thermodynamic analysis first, and the result shows that the new system is with electricity-electricity conversion efficiency of 53.82%, and energy conversion efficiency of 41.06%; The PHCA part has higher efficiency and the CAES part has higher capacity and energy density; Then, we performed exergy analysis on the CAES part with complex energy flow, and the result shows that the main input energy of the CAES part is from the compressor (76.05%), and the maximum loss occurs in the throttling (23.33%) of the high pressure air storage space and the heat storage (22.90%) process of the accumulator; Finally, we performed a sensitivity analysis on the system, and the result shows that increasing the pressure difference between the two storage spaces and the reheat temperature can improve the performance of the system, among which increasing the reheat temperature contributes the most. The electricity-electricity conversion efficiency of the system could be up to 77%.