Parametric assessment on the advanced exergy performance of a CO2 energy storage based trigeneration system

Abstract

In this paper, conventional and advanced exergy analyses are comprehensively introduced on an innovative transcritical CO2 energy storage based trigeneration system. Conventional exergy analysis can quantify in an independent way the component exergy destruction. However, the advanced technology is able to evaluate the interactions among components and identify the tangible promotion potential by allowing for the technical and economic limitations. In this method, the component exergy destruction is separated into avoidable and unavoidable parts, as well as the endogenous/exogenous parts. Calculation of the split parts is carried out by utilizing the thermodynamic cycle‐based approach. Results coming from conventional exergy analysis indicate that the first three largest exergy destructions are given by cold storage, compressor 1, and heat exchanger 3. However, advanced analysis results demonstrate that the cold storage, compressor 1, and compressor 2 should be given the first improvement priority in sequence by depending on the avoidable exergy destruction. The turbine efficiency produces a higher impact on overall exergy destruction than compressor efficiency. The pinch temperature in cold storage causes the highest effect on exergy destruction amongst all the heat exchangers. There exists an optimum value in the compressor inlet pressure and ambient temperature.