Optimizing exergy efficiency in solar-driven regenerative Brayton cycles with helium: A comparative study of four configurations for 100 MW power plants

Solar thermal energy is a promising RES due to its low CO? emissions and cost-effective thermal storage, which surpasses electric batteries used in photovoltaic and wind systems. Despite facing challenges such as lower efficiency, high capital costs, and the intermittent nature of solar resources, advancements in manageability, storage systems, solar collection optimization, and power cycles are under-way. Traditionally, subcritical steam Rankine cycles have been used in solar thermal plants but have limitations in adapting to solar resource variability and electrical demand. Recent proposals focus on Brayton cycles with helium as the working fluid, benefiting from helium's high thermal conductivity, specific heat, and inert properties. This study explores four configurations of regenerative Brayton cycles powered by solar energy to optimize the performance of a 100 MW power plant. The systems include a solar block with heliostats and a solar receiver, and a power block utilizing a helium Brayton cycle with components such as compressors, turbines, and recuperators. Simulation models for each configuration are developed using equation engineering solver, with detailed mass, energy, and exergy balances. The study aims to identify the most efficient configuration and optimize overall plant performance. The results contribute to the design and development of next-generation solar-driven Brayton cycle power plants, enhancing renewable energy systems' efficiency and sustainability.