Effect of the stack temperature on the thermal management of fuel cell powered aircraft

Abstract

In order to reduce emissions from commercial aviation, the industry and academia are investigating alternative power sources for future commercial aircraft. One promising concept is to use PEM fuel cells in combination with liquid hydrogen storage to provide electric energy for the aircraft’s auxiliary loads or for (hybrid-) electric propulsion [1, 2]. For a feasible design, the fuel cell system (stack and periphery components) will need to achieve exceptionally high specific powers, an efficient waste heat removal and a high overall electric efficiency. Moreover, the system will likely consist of multiple stacks of a significant size in order to achieve the required system-level power outputs of several hundred kW. Achieving these ambitious targets will likely require both improvements to the cell design and improvements to the cell materials. This contribution investigates pathways towards achieving the target of an efficient waste heat removal. The implications of the stack’s operating temperature on the cooling system mass and overall system specific power are assessed with the example of a 330 kW fuel cell system for the propulsion of a 70-seater regional aircraft. The results show that the design goals of a high specific power of the stacks and a low mass of the cooling system with a high overall system efficiency contradict each other and result in a tradeoff for the stack’s operating temperature and membrane type. [1] D. Guida and M. Minutillo,"Design methodology for a PEM fuel cell power system in a more electrical aircraft, Applied Energy, vol. 192, pp. 446-456, 2017. [2] T. Jarry, F. Lacressonnière, A. Jaafar, C. Turpin, and M. Scohy, Modeling and Sizing of a Fuel Cell-Lithium-Ion Battery Direct Hybridization System for Aeronautical Application, Energies, vol. 14, no. 22, p. 7655, 2021.