PERFORMANCE ASSESSMENT OF SUPERCRITICAL CO2 BRAYTON CYCLES IN SOLAR POWER TOWER SYSTEMS

This study investigates the thermodynamic performance of four supercritical carbon dioxide (sCO2) Brayton cycle configurations (Simple, Regeneration, Pre-compression, and Recompression) integrated within solar power tower systems. The main objective is to evaluate their efficiency and identify the most suitable configuration for solar power tower applications operating under high-temperature conditions. All configurations were modeled under fixed operating parameters representative of typical concentrated solar power plants: a turbine inlet temperature of 700 °C, a turbine inlet pressure of 25 MPa, an ambient temperature of 20 °C, and a total heat input of 120 MWth. The results show that the Recompression cycle achieved the highest thermal efficiency of 50.7%, followedby the Pre-compression (44.5%), Regeneration (37.7%), and Simple (13%) cycles. The superior performance of the Recompression configuration is attributed to reduced compression work and enhanced heat recovery through dual recuperators. Nevertheless, cooling and compression losses remain significant, limiting further efficiency improvement. Overall, this study demonstrates that the Recompression sCO2 Brayton cycle is the most efficient and technically viable configuration for future high-temperature solar power tower systems.