Performance Assessment of the Geometrical Parameters of a Cavity Receiver for a Thermochemical Reactor in a Solar...

Water splitting in thermochemical reactors, driven by concentrated solar energy, represents a promising and truly sustainable method for producing renewable hydrogen. However, the current efficiency of solar-to-hydrogen energy conversion indicates that significant technological improvements are needed before this process can become commercially viable on an industrial scale. To contribute to the advancement of thermochemical reactor design, this work evaluated different tube configurations inside a cavity receiver for a two-stage redox cycle driven by a 1.5 MWth solar tower plant. Specifically, six different configurations of 80 tubes were considered within a single-cavity receiver. The thermal requirements for the reduction step were met by changing the geometry of the passive reactors. Simulations indicated that multiple tube arrays can exceed the critical temperature of 1300 °C necessary for thermal reduction. Additionally, a closely spaced, single-layer configuration was found to be the most effective in minimizing temperature gradients within a chamber, which is essential to achieve uniform reaction conditions. This study demonstrates that an effective design of the internal tube layout is essential to control the complex thermal environment in solar cavity reactors and presents feasible configurations for solar hydrogen production in solar tower plants.