Thermal design and economic optimization of a solar tower for hydrogen production

• Novel integration of CSP with PEM electrolyzer is optimized for hydrogen production. • Exergoeconomic optimization achieves a minimum hydrogen production cost of $4.5/kg. • Thermal design is guided by exergoeconomic concept to reach optimum techno-economic performance. • Conjugate optimization can reduce hydrogen cost from 4.6 $/kg to 4.3 $/kg. • The hydrogen production cost is traced during daily transient radiation and thermal storage. Harnessing renewable energy for sustainable hydrogen production is a pivotal step towards a greener future. This study explores integrating solar tower (ST) technology with thermal energy storage and a power cycle to drive a PEM electrolyzer for green hydrogen production. A comprehensive investigation is conducted to evaluate the thermodynamic performance of the integrated system, including an exergoeconomic analysis to evaluate and optimize techno-economic performance. Exergy analysis reveals that the main components responsible for 84% of the total exergy destruction are the ST with 60%, the heat exchanger with 16%, and the electrolyzer with 8%. The hydrogen production cost varies with operational parameters, e.g., increased solar radiation reduces the cost to 4.5 $/kg at 1000 W/m 2 . Furthermore, the overall system performance is evaluated and monitored using overall effectiveness, exergy efficiency, and hydrogen production cost for full-day operation at hourly intervals based on the design set operating conditions versus optimized ones using the conjugate optimization. The findings indicate that the optimization improved the average overall effectiveness from 29.3% to 31.2%, and the average exergy efficiency from 36% to 40%, while the average hydrogen cost is reduced from 4.6 to 4.3 $/kg.