A General Approach to Compare A-CAES by Exergetic Analysis Considering the Real Gas Behavior of Air

Exergy analysis is a widespread tool for the detailed analysis of energy systems. The present paper gives an overview of exergetic analysis principles and methodologies in the scope of Adiabatic Compressed Air Energy Storage (A-CAES) plants. Furthermore, a modified exergy balance methodology for the investigation of A-CAES based on splitting the physical exergy of material streams into its pressure and temperature related part. This methodology is independent of the property data used and thus applicable both when considering ideal and real gas behavior. The exergetic balancing methodology presented in this paper enables the evaluation of the charging and discharging process decoupled from time-dependent losses occurring in the thermal energy storage and in the compressed air storage volume. Therefore, a more reliable exergetic analysis of the complex process of A-CAES systems can be performed, which supports the determination of the optimal design of all components.