Theoretical Analysis on Thermodynamic and Economic Performance Improvement in a Supercritical CO₂ Cycle by Integrating with Two Novel Double-Effect Absorption Reheat Power Cycles

Abstract

To enhance the overall performance of recompression supercritical carbon dioxide- (sCO(2)-) based systems, two new double-effect absorption reheat power cycles (DARPC) were developed in this study. These methods are based on the typical absorption power cycle (APC). For the proposed sCO(2)/DARPC systems, a parametric analysis of the thermodynamic and economic performances, as well as additional parametric optimisations, were performed quantitatively. The results indicate that replacing the APC subsystem with DARPC subsystems can enhance the total function of the sCO2 system even further, owing to the increased H2O vapour created in the separator and the reheating process, which adds to the greater net power output. Furthermore, compared to the DARPC2 subsystem, the DARPC1 subsystem may produce more H2O vapour from the generator and separator, resulting in an increase in net output power. When compared to a single sCO(2) power cycle, multiobjective optimisations showed that the sCO(2)/DARPC1 and sCO(2)/DARPC2 systems could increase the exergy efficiency by 12.95% and 11.51% and decrease the total product unit cost by 9.67% and 8.37%, respectively. Furthermore, the sCO(2)/DARPC1 and sCO(2)/DARPC2 systems can achieve improvements in exergy efficiency of 4.95% and 3.61% and a total product unit cost of 4.52% and 3.15%, respectively, compared with the sCO(2)/APC system.