Impact of Oxygen Concentration on High-Load PEMFC Efficiency: A Simulink-Based Study

Energy consumption and the utilization of sustainable energy sources are of great importance for the economic independence and environmental stability of nations. Turkey, as a country heavily dependent on energy imports, faces a critical need to develop domestic and renewable energy resources. The low carbon emissions and environmentally friendly nature of hydrogen have attracted significant attention within the scope of international agreements such as the Kyoto Protocol. Proton Exchange Membrane Fuel Cells (PEMFCs) stand out among clean energy technologies due to their low operating temperatures (60–80°C), high power density, and zero-emission potential. However, concentration losses occurring on the cathode side under high load conditions represent a significant problem that considerably reduces PEMFC efficiency and has not been sufficiently addressed in the literature. This study investigates the effect of inlet air O₂ on PEMFC efficiency under different load conditions using a MATLAB-Simulink simulation model. The results demonstrate that increasing the oxygen concentration under 50% load conditions yields only a marginal efficiency improvement of approximately 3%. In contrast, under 90% load conditions, increasing the O₂ enrichment level from 21% to 100% improves efficiency by approximately 10%, and this gain can reach up to 15% with additional pressurization measures. This finding clearly demonstrates that increasing oxygen concentration provides a meaningful contribution only under high load conditions, while such intervention is unnecessary within the optimal load range. The results present a practical strategy for improving PEMFC efficiency in heavy-load applications such as intercontinental cargo ships and freight trains, and directly contribute to the literature on PEMFC systems operating under high load conditions.