Optimization of the configuration in a CAES-TES system

A compressor with heat recovery is thermodynamically analyzed from a second-law point of view, in terms of entropy generation minimization. The unit is optimized, accounting for heat exchange and pressure loss irreversibility, and the maximum output is found, in terms of combined mechanical and thermal energy, for a given input energy at the compressor shaft. This analysis is intended as a part of the thermal optimization on a CAES TES (Compressed Air Energy Storage with Thermal Energy Storage) plant. The latter, if an artificial reservoir is used for compressed air, requires high operating pressure. Hence, this work focuses on a staged compression with intermediate refrigeration. The principle of equal distribution of irreversibility, which is one of the aspects of the “Constructal Law” is then demonstrated. From these findings, a good approximation can be found for the optimal configuration of a complex multi-stage system.