| Summary: | [Introduction] Supercritical CO2 (sCO2) Brayton cycle is a promising technology to improve the efficiency of concentrated solar power systems. [Method] This paper presented an equation-based nonlinear programming model for the analysis and optimization of the power tower concentrated solar power (CSP) coupled with supercritical CO2 (sCO2) Brayton cycles. The model included CSP subsystems, sCO2 Brayton cycle, and high accuracy equation of state, enabling simultaneous optimization of the systems with arbitrary number of decision variables. Case studies of the integrated CSP-simple sCO2 Brayton cycle and CSP-recompression sCO2 Brayton cycle systems were carried out to determine their optimal design. [Result] The results show that thermal efficiency of the CSP-recompression cycle system can reach a maximum of 29.4%, higher than the 24.9% of the CSP-simple cycle system. The optimal turbine inlet temperature is 901 K for the CSP-recompression cycle system, 826 K for the CSP-simple cycle system. The optimal expansion ratios of the CSP-simple cycle system are greater than 3.2 at the investigated temperature range, and are approximately equal to 3 for the CSP-recompression cycle system. [Conclusion] There are optimal turbine inlet temperatures and compression ratios for the integrated systems.Additionally, the compression ratio has a greater impact on the thermal efficiency of the CSP-simple cycle system.
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