Hydrogen fuel cells for aviation? A potential analysis comparing different thrust categories

Abstract

Reference No. ISABE-2022-291 - The emission of greenhouse gases is causing a rising global average temperature and extreme climate events. The European Commission has set ambitious goals until 2050 to reduce CO2 and NOx emissions in aviation. But to reach these goals revolutionary developments are necessary since the optimization potential of conventional technologies is limited. Propulsion systems powered by proton exchange membrane fuel cells (PEMFC) emit only water vapor and would reduce the climate impact of aviation. Therefore, the feasibility of hydrogen powered PEMFC propulsion systems for the application in different aircraft categories is analyzed. A basic fuel cell model is integrated in the virtual engine framework GTlab. The influence of major design parameters on the behavior of the system is analyzed. Fuel cell-based propulsion systems are designed for four aircraft applications that differ in flight operating conditions, payload and range. The designed hydrogen fuel-cell-powered propulsion systems are compared to the corresponding conventional kerosene-fueled engines. The implications on system efficiency, size and mass including the hydrogen storage are discussed. High operating temperatures (e.g. 180°C) are crucial to keep the cooling system at a reasonable size. For a current technology level, a typical regional aircraft application with a mission range of 1320 km shows the lowest weight increase (18% of TOWref). Assuming a technology level for entry into service in 2040, the mass increases by only 7.4%. For a short- to mid-range scenario with future assumptions the mass increases by 55% of TOWref. These results are achieved neglecting the impacts on the aircraft design. Anyhow, a fuel cell powered propulsion system is not convenient for aircraft with high thrust requirements. Combined with the results of two additional scenarios (general aviation, commuter aircraft), this work is the basis for future research in fuel cell-based propulsion systems in civil aviation.