Multi-physics model development and application to real-case alkaline electrolyzer

The realization of mathematical, multi-physics models for alkaline electrolyzers is crucial for advancing this technology. Lumped parameter models offer shorter simulation times, compared with other approaches, and practical industrial applications. If electrochemical models provide the polarization curve, the hydrogen production rate, and the device efficiency, thermal models solve the equations involving the electrolyte temperature. With a coupled approach, the two models can be linked together by considering the device voltage as temperature dependent. Despite the relevance of such models, few instances of their direct application on existing electrolyzers can be found in the literature, and combined electrochemical-thermal simulations are rare. This study presents a multi-physics model applied on an alkaline electrolyzer and validated against measurements acquired on a dedicated experimental test bench. The physics-based model accurately predicts the polarization curve, exhibiting a high precision match with experimental data. Additionally, it identifies material or geometrical imperfections in the electrolyzer, allowing for optimization in the design phase. The thermal model successfully converges to the desired electrolyte temperature of 72 °C under stationary conditions. Additional transient simulations demonstrate an average deviation of only 0.25% compared to the measured temperature trend. Finally, a sensitivity analysis explores the coupling of the electrolyzer with a wind turbine under different wind conditions. The study showcases the effectiveness of the coupled electrochemical-thermal model in predicting electrolyzer performance, with a direct application to a wind turbine power output.