Design and assessment of a combined solar energy system with storage and power production

The present study aims to develop a novel design of an integrated energy system that synergistically integrates an open-loop Brayton cycle and closed-loop Rankine cycle with solar assisted thermochemical hydrogen production system. Three tailored configurations are simulated to operate in the charging phase during peak solar hours, in low solar radiation periods, and in the discharging phase without solar radiation. The combined cycle power system is comprised of concentrated solar collectors configured to concentrate solar radiations, a topping cycle configured to generate electricity by expanding the first working fluid, and a bottoming cycle configured to generate electricity by utilizing the exhaust heat of the topping cycle. The developed configurations aim to simultaneously achieve clean power production and heat storage for later use. The Aspen Plus process simulator is employed to solve the mass and energy balances at steady-state conditions. The open loop Brayton cycle parameters (such as split ratio, and turbine pressure), discharging parameters (temperature), and system performance indicators (energy and exergy efficiencies) are also examined. For the charging configuration, the optimized turbine pressure and split fraction are 6 bar and 0.5, which results in an oil temperature of 400.64°C. The overall energy and exergy efficiencies of the charging configuration are 98.26% and 48.36% respectively. The overall energy and exergy efficiencies of the discharging configuration are 69.34% and 39.54% respectively. • An integrated energy system combines Brayton and Rankine cycles with solar power. • Three configurations are simulated for peak solar, low solar, and discharging phases. • The system utilizes concentrated solar collectors and dual power cycles. • Solar energy is stored in the form of Thermonol-VP1. • The discharging configuration achieves energy and exergy efficiencies of 69.34% and 39.54%.