Overview

Concentrated solar power can thermally drive redox reactions to produce precursors such as H₂ and CO, which can then be upgraded to synthetic fuels for decarbonizing carbon-intensive sectors including iron and steel, cement, heavy transport, and aviation. Two-step metal oxide redox cycles using an oxygen intermediate (OI) have emerged as a promising approach for such solar thermochemical (STCH) fuel production, typically implemented in directly illuminated receiver–reactor (DIR) systems where a single cavity functions as both solar receiver and redox reactor. However, practical indirectly heated reactors (IdHRs) which can offer 24*7 operation and high solar-fuel efficiency remain unexplored.​

I will focus on Gallium-doped Lanthanum Strontium Manganese perovskite OI in form of a dual-porosity reticulated porous foam and its redox performance and stability in a lab-scale vertical tube furnace reactor across a range of temperatures and steam flow rates. Further, to evaluate performance under indirect heating, I designed an IdHR prototype to be coupled with a 10-kW solar receiver, where steam at ~1300°C serves as the HTF to deliver the heat required for the redox reactions.​

The 10-kW solar receiver is a propriety technology, fabricated and supplied by Synhelion which achieves a cavity temperature of ~1500°C. The shell and tube-inspired design of the IdHR was developed through numerical simulations in ANSYS Fluent. The proposed design accounts for practical OI aspect ratios while minimizing radial and axial temperature gradients to improve OI utilization. Overall, this work provides a design framework for indirectly heated solar fuel reactors, offers guidelines for integrating them with existing high-temperature solar receiver technology, and delineates pathways for scaling up solar-driven fuel production systems.