The influence of charging process on trigenerative performance of compressed air energy storage system

Abstract

Adiabatic compressed air energy storage system (ACAES) has a natural advantage on trigeneration combined cooling, heating and power. A dynamic model coupled with exergy calculation is developed and the charging strategy for trigenerative application is focused on. The dynamic characteristic of ACAES is performed and the effects of charging mode, number of compression stages and thermal energy storage on the characteristic of trigenerative application are obtained. The sliding-pressure charging mode is suggested for the trigeneration due to 3.92% higher exergy efficiency than that of constant-pressure charging mode. Asymmetrical arrangement of ACAES with more compression stages is efficient for its trigenerative application especially increasing heating and cooling supplies with 2.9% exergy efficiency improvement. Furthermore, changing mass flow rate of thermal energy storage medium (ie, water) shows an outstanding ability to vary the cooling, heating, and power supply ratios in a very wide range.Besides, the economic analysis is carried out which addresses the obvious economic improvement by trigenerative application of ACAES. Accordingly, joint regulation of compression stages and water mass flow rate is suggested to be an efficient and economic approach to adjust the distribution of cooling, heating and electricity supplies according to the user's demand.