Dynamic simulation of a Re-compressed adiabatic compressed air energy storage (RA-CAES) system

Abstract

In this work, a novel re-compressed adiabatic compressed air energy storage (RA-CAES) system is proposed to raise the operating pressure of the expansion train. In the discharging process, a compressor is employed to enhance the low-pressure air from storage vessels to the operating pressure. Off-design models for components have been established and experimental data available in the open literature are adopted for validation. Potential induced degradation (PID) control technology is employed to control the outlet temperature of the air in inter-cooling and after-cooling heat exchangers. The calculation results for the components have been presented and discussed. Meanwhile, the system performances of the proposed RA-CAES are compared with that of conventional A-CAES. The comparison results show the round trip efficiency (RTE) of RA-CAES is 69.89%, while it is only 65.23% for A-CAES, and the increment of RTE between A-CAES and RA-CAES is 4.66%. The influence of isentropic efficiencies of turbine and compressor is also investigated, the RTE of RA-CAES is always higher than that of A-CAES, and the minimum increment of RTE is near 4%. Overall, this study presents valuable insights into the design of A-CAES, the proposed RA-CAES is more efficient than the conventional A-CAES.