Thermodynamic and advanced exergy analysis of a trans-critical CO2 energy storage system integrated with heat supply and solar energy

Abstract

In order to improve the utilization of renewable energy in energy applications and to solve the problem of intermittency in the process of solar energy application, this paper introduces a trans-critical CO2 energy storage system integrating solar energy and heat supply, and thermodynamic analysis and advanced energy efficiency analysis of the system are carried out. The system demonstrates impressive performance under standard conditions, achieving an energy storage efficiency of 77.19 %, and an exergetic efficiency of 68.03 %. The system's maximum avoidable exergy destruction is 4.17 MW, representing 68.77 % of the total exergy destruction, indicating significant potential for improvement. When it comes to component optimization, there are disparities in the results obtained through conventional exergetic analysis and advanced exergetic analysis. Conventional exergetic analysis suggests that the Reheater 4 should be optimized initially, followed by expander 1 and intercooler 3 optimization. However, according to advanced exergetic analysis, the recommended sequence is to optimize the Reheater 4 first, followed by expander 1 and intercooler 3. Advanced exergetic analysis reveals a significant endogenous exergy destruction of 68.23 % within the system, indicating weak inter-component relationships. Consequently, the primary focus should be optimizing the components themselves, with special emphasis on the RE4 and intercooler 3, as they have the largest exergy destructions.