Design and optimization of a modified solar-driven energy system utilizing advanced heat recovery methods for electricity and hydrogen production in sustainable urban applications

This study proposes a novel concentrating solar power (CSP)-based energy system designed to enhance energy efficiency and sustainability for a commercial building in Riyadh, Saudi Arabia. The system integrates a heliostat field with advanced technologies, including the Kalina cycle (KC), thermoelectric generator (TEG), Rankine cycle (RC), and proton exchange membrane (PEM) electrolyzer, to simultaneously generate electricity and hydrogen. Waste heat recovery is utilized to improve energy efficiency and support heating, ventilation, and air conditioning (HVAC) systems, while the produced hydrogen is stored for use during peak demand or nighttime. A comprehensive techno-economic simulation evaluates the system's performance from energy, exergy, and economic perspectives, with sensitivity analysis identifying critical parameters. Key findings reveal that higher direct normal irradiation (DNI) significantly enhances system performance, increasing electricity generation from 2885 kW to 6310 kW and hydrogen production from 16.92 to 36.94 kg/h. Optimization of pressure ratios in the Brayton cycle and lower pinch point temperature differences further improve efficiency and cost-effectiveness. The hybrid optimization approach, combining artificial neural networks (ANNs) and a genetic algorithm (GA), reduces optimization time from 183 hours to 4 minutes, achieving an exergy efficiency of 24.42 % and a cost rate of 310.51 $/h. The system achieves annual hydrogen production of 197,706.4 kg, with peak electricity output of 4025 kW in July. This scalable and efficient energy solution reduces reliance on external energy sources, contributing to sustainable urban energy systems.