Thermodynamic analysis of multiple power generation system with solar powered CO2 brayton cycle

Concentrated solar power technology represents an effective and sustainable solution for large-scale renewable electricity generation in regions with high solar irradiation potential. In this study, a solar power tower assisted cascaded multigeneration system specifically designed for Mediterranean climatic conditions was developed and comprehensively evaluated. The proposed configuration integrates a subcritical CO2 Brayton cycle, a bottoming Rankine cycle, and a multi-effect distillation unit into a single synergistic framework. The analysis revealed that under peak summer solar conditions, the system achieves a maximum net power output of 23.48 MW and a freshwater production rate of 14.25 kg/s. These results demonstrate that the proposed integrated configuration enables not only continuous electricity generation but also sustainable freshwater production throughout the year. Energy and exergy based evaluations showed that during high solar availability periods, the system provides a CO2 emission reduction potential of 27 434.55 kg per hour, highlighting its significant environmental contribution. The integrated Sb-CO2–sRC–Desalination configuration achieved overall thermal efficiencies ranging between 0.39 and 0.43, while the exergy efficiencies of the Sb-CO2 Brayton and Rankine subsystems reached 0.58 and 0.73, respectively. Sensitivity analyses indicated that the performance of the Sb-CO2 cycle is highly dependent on pressure, reaching its optimum operating point at approximately 10 bar and 1100 °C turbine inlet temperature. In contrast, the Rankine cycle exhibited a consistent increase in efficiency with rising pressure levels. From an economic perspective, the total investment and operating costs of the proposed configuration correspond to a simple payback period of 15.3 years, confirming its economic viability under Mediterranean conditions. Overall, the proposed multigeneration system demonstrates a well-balanced performance in terms of energy, exergy, and economic criteria. It offers a fuel-independent, environmentally friendly, and scalable solution for sustainable large-scale electricity and freshwater production, presenting a promising alternative for future solar-driven energy-water cogeneration applications.