On the Design and Operation of the Thermal Management System of PEMFC-Powered Aircraft

Hydrogen fuel-cell-powered all-electric aircraft are promising for decarbonizing short-range aviation, but the substantial low-temperature waste heat demands a compact thermal management system (TMS). This study presents a methodological framework for the integrated co-design of the TMS and powertrain using multi-objective optimization and holistic mission-level analysis to identify optimal TMS designs and operating strategies. Changes in TMS net drag translate into changes in required aircraft thrust, while changes in powertrain, TMS, and fuel mass affect the available payload under a constant maximum take-off mass assumption. This iterative process yields performance metrics across TMS cooling architectures (parallel or series), heat exchanger mass-drag characteristics, coolant temperature targets (50, 70, or 90 °C), and installation objectives (minimizing mass or ram-air duct length). The optimal design is a parallel cooling architecture that balances mass-specific heat rejection of 4.77 kW kg−1 at hot-day take-off with drag-specific heat rejection of 1.29 kW N−1 at standard-day cruise. A reduction in coolant temperature at standard-day missions entails no significant performance penalties and could improve the efficiency of electrical components. A shorter ram-air duct significantly decreases the available payload by 630 kg but may facilitate nacelle integration. The findings underscore that holistic TMS-powertrain co-design and optimization is essential for rigorous design of sustainable all-electric aircraft.