Solar-driven chemical looping combustion: A pathway to low-impact carbon emission and sustainable hydrogen generation for a decarbonized energy sector

Abstract

This study investigates a solar-driven chemical looping combustion (CLC) system for sustainable hydrogen production. A high-temperature CLC model was developed and optimized through sensitivity analysis, revealing that increasing iron steam reactor pressure (optimal: 40 bar) and steam flow rate enhances hydrogen production by up to 28 %, while higher solar‑iron reactor pressure reduces output by 19 % due to reaction equilibrium constraints. The solar-CLC hybrid system demonstrated superior performance, with the high-temperature model producing 10,500 kmol/h of hydrogen—96 % more than the low-temperature model (5348 kmol/h) and 135 % more than non-solar CLC. Exergy analysis confirmed the iron-steam reactor as the most efficient component (90 % efficiency), whereas the iron-fuel reactor exhibited the highest losses (50 % efficiency). Shiraz as the most favorable location, required 32 % fewer mirrors than Ahvaz (the least suitable city) due to its higher solar irradiance (123.2 vs. 88.6 kWh/m² DNI). Chabahar achieved the highest hydrogen yield (11,803 kmol/day) owing to extended daylight hours. Phase-change material storage analysis showed Chabahar needed 40 % fewer storage modules than Shiraz. Solar-CLC integration outperforms traditional CLC in both efficiency and emissions reduction, with the high-temperature model being optimal for high-irradiance regions. The findings provide actionable insights for deploying renewable-powered hydrogen systems in decarbonizing the energy sector.