Thermodynamic assessment of a molten salt solar power tower integrated with a supercritical CO2 Brayton cycle under Brazilian solar conditions

This study evaluates the thermodynamic performance of a 100 MWe solar power tower (SPT) plant using molten salt as the heat transfer fluid and thermal energy storage (TES), integrated with a supercritical CO₂ recompression Brayton cycle. Simulations were conducted for five Brazilian locations with varying solar resources: Chapada dos Guimarães, Januária, Monte Alegre, Petrolina, and Rio Grande. The thermodynamic cycle was validated against literature and optimized for thermal efficiency. A turbine inlet temperature of 565 °C and a thermal input of 206.8 MWt resulted in a cycle efficiency of 48.36 %. Parametric analyses were performed for solar multiples (SM = 1–3) and TES durations (0–15 h). Results show that a 15-hour TES and SM of 3 optimized the capacity factor (CF) in most locations, reaching up to 100 % in Chapada dos Guimarães. The southern site (Rio Grande) required a lower SM (2.5) for optimal performance. Despite regional differences in direct normal irradiance, all configurations demonstrated the feasibility of CSP deployment in Brazil.