Combined direct oxy-combustion and concentrated solar supercritical carbon dioxide power system—Thermo, exergoeconomic, and quadruple optimization analyses

Abstract

For the global future energy systems, concentrated solar power (CSP) and direct CO2 capture systems are of the most important key technologies, however, each of these systems has shortcomings. This study addresses the solar intermittency and power control complexity of the CSP systems and the substantial energy penalty of the direct oxy-combustion (DOC) supercritical carbon dioxide (sCO2) power systems by integrating both systems. Herein, innovative power cycle configurations that integrate the CSP tower system with DOC sCO2 power cycle are introduced. The configurations include two basic cycles for comparison and validation purposes and three integrated cycles. The basic configurations are: an intercooled sCO2 power cycle driven by DOC system (S1), and a stand-alone basic CSP tower system (S2). The integrated configurations are: CSP/DOC system where the CSP works as a preheater (S3); CSP/DOC system where the CSP works as a reheater (S4); and CSP/DOC system where each system heats part of the working fluid to drive its high-pressure turbine (S5). The hybrid configurations reduce the fuel and the parasitic power consumptions of the basic DOC systems (S1) and reduce the capital cost associated with the conventional CSP systems (S2) by eliminating the need for thermal storage. Over practical ranges of operational parameters, comprehensive thermoeconomic, exergoeconomic, and optimization analyses for the proposed configurations are performed. Compared to the conventional CSP system, the LCOE of the hybrid system is lower by 50%. Among the hybrid configurations, the energetic and exergetic performances of S4 are the best with the lowest LCOE. According to the optimization analysis, S4 has a thermal efficiency of 55.29% at LCOEs of 7.705¢/kWh. S3, S5, S2, and S1 have thermal efficiencies of 52.90%, 48.72%, 45.56%, and 40.54% at LCOE of 7.970, 8.138, 7.864, and 6.351¢/kWh, respectively.