Optimized Operational Strategy of a Solar Reactor for Thermochemical Hydrogen Generation

Hydrogen plays an important role in a sustainable future global energy system. An interesting technology for generating renewable hydrogen is splitting of water via concentrated solar power by thermochemical two-step redox cycles. This technology has a much higher potential solar-to-fuel efficiency compared to photovoltaics with subsequent electrolysis. Here we present new results on the optimization of the operational process strategy of a large-scale 250 kW pilot plant consisting of a fixed bed reactor using ceria as reactive material. The considered tuning parameters are chosen as essential process parameters: operation temperatures within the two steps, corresponding fluid flows, as well as switching times within the two steps. Design limitations of employed materials and components are taken into account within the optimization; thus, the obtained results can be validated in practice. For the optimization it is employed a complex physical system model with more than 3500 states, which has been validated before by two measurement campaigns. Regarding reduction temperatures between 1400–1700 ^∘ C the maximum efficiency is determined with up to 5.6