The transition to sustainable propulsion in maritime transport has highlighted hydrogen-fueled PEM fuel cells as a compelling alternative to conventional diesel engines, driven by increasingly stringent emission regulations. While significant research has focused on single fuel c
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The transition to sustainable propulsion in maritime transport has highlighted hydrogen-fueled PEM fuel cells as a compelling alternative to conventional diesel engines, driven by increasingly stringent emission regulations. While significant research has focused on single fuel cells or complete stacks, the hydrogen loop, the subsystem responsible for delivering, recirculating hydrogen, remains underexplored, particularly in the context of maritime applications. The hydrogen loop plays a critical role in determining system efficiency, reliability, and performance. Improper management of flow, pressure, temperature, and humidity can lead to lower efficiency, membrane dehydration, flooding, or even irreversible damage to the stack. To address this, a novel dynamic MATLAB Simulink model was developed to evaluate hydrogen loop configurations under realistic maritime conditions. This thesis investigates the design and performance of twelve distinct hydrogen loop configurations, each comprising different combinations of supply and recirculation components such as pressure regulators, proportional valves, mass flow controllers, liquid ring pumps, blowers, and ejectors. The configurations are motivated by real-world implementations from an inland vessel and a fuel cell-powered race car, as well as conceptual arrangements aimed at exploring broader designs. A novel, dynamic MATLAB Simulink model was developed that uniquely integrates pressure, temperature, humidity, twophase flow, and phase change dynamics, to capture both transient and steady-state behavior of hydrogen loops under realistic maritime conditions. Unlike existing models, it allows detailed componentlevel interaction analysis and configuration-specific scoring under a standardized testing framework. Key governing equations are based on established physics principles, and the model is validated using experimental data from the H2 Barge 1, an operational hydrogen-powered inland vessel from Future Proof Shipping. Each configuration is evaluated across a range of criteria, including hydrogen utilization, power consumption, performance, pressure and temperature robustness, stoichiometry control, and system response under transient loads. Special attention is given to component interactions that influence overall system behavior, such as the influence a recirculation device has on humidity and temperature, or the limitations of ejectors in low-load scenarios due to their dependency on primary flow pressure. Hybrid configurations combining ejectors with mechanical pumps are also explored to mitigate operational limitations at low power setpoints. The results highlight that hydrogen loop configuration choices have a significant impact on system performance, control flexibility, and design complexity. Ejector-based systems are energy-efficient and mechanically simple but suffer from limited operational range and lack dynamic control, especially at low loads. Mechanical recirculation devices like blowers and liquid ring pumps offer robust performance across the full load range and enable flexible operation, though they come with higher energy consumption and potential mechanical wear. Supply components also influence system behavior: proportional valves allow dynamic pressure control but require careful tuning, while mass flow controllers simplify control logic but lack pressure regulation. Hybrid solutions, combining ejectors with pumps, can mitigate some limitations but add complexity. Among the twelve configurations studied, the proportional valve–blower setup emerges as the most suitable for maritime fuel cell applications, offering the best balance of efficiency, operational flexibility, robustness, and system simplicity. Ultimately, this research provides a structured methodology for comparing hydrogen loop configurations, enabling system designers to make informed decisions based on specific performance requirements and operational constraints. The findings underscore the importance of integrated system modeling in BoP design and contribute to the broader goal of developing scalable, reliable, and efficient hydrogen propulsion systems for maritime applications.