High-temperature electrolysis for reducing H₂O (and CO₂) to H₂ (and CO) converts concentrated solar energy into fuels and chemical feedstock. We invented an integrated reactor concept comprising a solar cavity receiver for reactant heating, a solid oxide electrolyzer (SOE) stack for water electrolysis, and concentrated photovoltaic (PV) cells for the SOE stack’s electricity demand. A numerical model compared thermoneutral and endo/exothermal operation of the SOE stack. Without heat recovery, we predicted a maximum solar-to-hydrogen (STH) efficiency of 19.85% (assuming 20% PV efficiency and 20% heat losses in the solar cavity receiver) and preferentially endothermal operation. Heat recovery further improved the performance. We demonstrated a 2.5 kW (17% electrical and 83% thermal input) reactor, incorporating a commercial 16-cell Ni/YSZ/LSM SOE stack into a double-helical solar cavity receiver, with 3.33% STH efficiency (assuming 20% PV efficiency). The experimentally supported analysis indicates that endothermal operation increases the performance and predicts STH efficiencies encouraging intensified research and technology development.

_{将H 2} O（和CO ₂）还原为H ₂的高温电解（和 CO）将集中的太阳能转化为燃料和化学原料。我们发明了一种集成反应堆概念，包括用于加热反应物的太阳能腔接收器、用于水电解的固体氧化物电解槽 (SOE) 堆，以及用于 SOE 堆电力需求的聚光光伏 (PV) 电池。一个数值模型比较了 SOE 堆栈的热中性和吸热/放热操作。在没有热回收的情况下，我们预测最大太阳能制氢 (STH) 效率为 19.85%（假设太阳能腔接收器中的光伏效率为 20%，热损失为 20%）并且优先吸热操作。热回收进一步提高了性能。我们展示了一个 2.5 kW（17% 电输入和 83% 热输入）反应器，将商用 16 节 Ni/YSZ/LSM SOE 堆栈集成到双螺旋太阳能腔接收器中，其中 3. 33% STH 效率（假设 20% PV 效率）。实验支持的分析表明，吸热操作提高了性能并预测了 STH 效率，鼓励加强研究和技术开发。