Non-isothermal numerical modeling of solid oxide electrolysis cell with an additional channel for thermal enhancement and hydrogen production optimization

Solid Oxide Electrolysis Cell (SOEC) represent a highly promising solution for sustainable hydrogen production due to their ability to perform high-efficiency electrolysis at elevated temperatures (700–1000 °C). However, one of the major challenges in their reliable operation is the formation of significant thermal gradients, which arise from endothermic reactions, ohmic heating, and heat dissipation. This study introduces an innovative SOEC design that incorporates an additional heat transfer channel adjacent to the cathode and a revised gas flow configuration. The objective of this design is to enhance temperature uniformity, mitigate thermal stresses, and boost hydrogen generation efficiency. To assess the effectiveness of the proposed configuration, a comprehensive adiabatic multiphysics model was developed using computational fluid dynamics (CFD) coupled with electrochemical kinetics. A close match is observed between the numerical model and experimental data, with differences of only 3.4% at 900 °C and 6.5% at 1000 °C. This model simultaneously accounts for heat transfer, fluid dynamics, electrochemical processes, and internal heating phenomena. Five distinct flow scenarios of cathode, anode and additional channels were simulated to evaluate key performance indicators, including the hydrogen molar production rate, current density distribution, internal pressure, and thermal stress profiles. Simulation results demonstrated that the integration of the additional heat channel led to increases in hydrogen output of 7.51% at 1.1 V, 6.58% at 1.3 V, and 1.1% at 1.5 V. Enhanced performance is observed only under thermally favorable conditions (T inlet,additional channel ≥ T cell ), where increased flow rates improve thermal regulation. Below critical temperature thresholds, convective cooling dominates, while intermediate conditions yield thermochemical neutrality.