Conventional and advanced exergy analysis of large-scale adiabatic compressed air energy storage system

Abstract

Identifying the main sources of exergy destruction is a significant method for promoting high-efficiency operation of compressed air energy storage (CAES) systems. Advanced exergy analysis is free from the limitations of traditional exergy analysis and identifies the optimization order of the components and clarifies their relationships. This method is significant for developing system improvement strategies for optimization. In this study, based on the actual engineering of an adiabatic compressed air energy storage (A-CAES) power plant, real, unavoidable, and hybrid thermodynamic cycles were established, and conventional and advanced exergy analyses were conducted for it. The results showed that the endogenous exergy destruction of the main components was greater than the exogenous exergy destruction, implying the importance of optimizing the components. In addition, endogenous and exogenous exergy destructions indicate a highly complex relationship between the components. The avoidable exergy destruction indicated the highest potential for improvement of the third-stage heat exchanger (HEX3) contributing to 13.15 % of the total avoidable exergy destruction of the system; therefore, HEX3 has the highest optimization value. In addition, the second-stage heat exchanger (HEX2) and first-stage heat exchanger (HEX1) also exhibited higher potential for improvement.