## 4 Discussion  
This study demonstrates significant advancements achieved through the development of a novel pressurized air cabin system for open-cathode PEM fuel cells. By optimizing the system's geometry and operational parameters, the results indicate measurable enhancements in fuel cell efficiency, hydrogen utilization, and energy performance compared to conventional setups. The study's experimental and computational findings highlight the critical role of pressure distribution and uniform oxygen delivery in achieving balanced electrochemical reactions across the fuel cell stack. Firstly, the optimization of the pressurized air cabin using the Taguchi method yielded a 3.68% increase in the uniformity index (UI), ensuring a more consistent oxygen supply to the fuel cell stack. Simultaneously, the pressure drop was reduced by 7.69%, achieving values that outperform conventional air  
Figure 24: Experimental and simulation results for hydrogen consumption. supply designs. These enhancements improved operational stability, reduced localized oxygen depletion risks, and contributed to extended fuel cell durability and lifespan. Secondly, the experimental validation highlighted significant energy efficiency benefits. The power performance improved by 9.4%, showcasing the superior capability of the pressurized cabin to operate the air compressor at its most efficient point. The system demonstrated consistent operation, minimizing inefficiencies and supporting better fuel utilization even under dynamic operating conditions. Notably, the maximum error between experimental and simulation results for compressor architectures was 7.6%, indicating a high level of accuracy in the developed models. However, it is crucial to acknowledge the limitations and assumptions of the modeling approach, which impact the overall accuracy of the results. The 1D mathematical model used in this study simplifies the complex multidimensional airflow distribution and local phenomena within the fuel cell system. While this approach enables efficient computational simulations, it does not fully capture the non-uniform airflow effects, localized temperature gradients, or reactant transport phenomena that could influence system performance. Additionally, the hydrogen consumption analysis further underscores the system's efficiency. The compressor architecture demonstrated a 7.9% reduction in peak hydrogen consumption and an 8.3% reduction in average hydrogen consumption compared to the fan architecture. These improvements were observed across a wide range of operating conditions, from low to high ambient temperatures. At low temperatures (\(-20\)\({}^{\circ}\)C), the compressor variable configuration reduced hydrogen consumption by 9.0% compared to the fan constant configuration. Even at high temperatures (40 \({}^{\circ}\)C), where efficiency gains typically narrow, the system still achieved a 2.4% reduction in hydrogen consumption. Several factors contribute to the observed errors and discrepancies between experimental and simulation results. Sensor reading errors and small inaccuracies in hydrogen consumption, temperature, and airflow measurements may influence the validation process. Vehicle driver-induced variations introduce real-world operation variability in driving behavior, which can affect energy consumption and system performance. Thermal modeling simplifications, where the assumed uniform heat dissipation model does not account for localized hot spots and transient temperature fluctuations within the fuel cell stack, may impact the accuracy of results. Additionally, idealized fan and compressor models were used, simplifying the aerodynamic characteristics of the fan and compressor, which may slightly overestimate or underestimate their efficiency under dynamic load conditions. Future improvements should focus on higher-dimensional modeling approaches such as computational fluid dynamics (CFD) simulations.