Pressure and Temperature Effects on PEMFC/DMFC Performance: CFD-Driven Insights into Efficiency, Reactant Distribution, and Thermal Management

This study investigates the performance of PEM and DMFC systems under varying operational conditions, focusing on their thermodynamic efficiency, electrochemical behavior, and fluid dynamics. Using computational fluid dynamics (CFD) simulations and thermodynamic analysis, the impact of temperature (50–100°C) and pressure (1–10 bar) on hydrogen and methanol-based energy carriers was evaluated, alongside stress distribution, gas velocity, and temperature gradients in single cells and stacks. Results revealed that elevated pressure enhances reactant flow uniformity and reduces electrochemical losses, improving PEM cell efficiency by up to 5%, while higher temperatures increase activation overpotential, particularly in DMFCs. Thermodynamic analysis demonstrated that methanol oxidation releases three times more heat than hydrogen reactions, yet PEM systems exhibit superior stability at moderate temperatures. Simulations further highlighted optimal operating conditions—high pressure (10 bar) and moderate temperature (65–80°C) to balance efficiency, durability, and safety. These findings underscore the importance of tailored system design for PEM and DMFC applications, offering actionable insights for optimizing energy storage integration, reducing environmental footprints, and advancing renewable energy systems.