Exploring Hydrogen for Short-Range Flight

A new look at hydrogen fuel cell airplane design suggests that zero-emissions aviation could be possible in the future — at least for small, short-range flights.

The research comes out of Sweden, which has set a goal to decarbonize its regional aircraft by 2030, and where government initiatives to support hydrogen fuel are greater than in the U.S. According to the authors, Sweden’s first hydrogen-powered flights could take off as early as 2028, and the vast majority of air trips under 750 miles (1,200 km) could be hydrogen-powered by 2045.

Achieving this goal still requires turning a model of a 50-person regional aircraft, based on the commonly used ATR 42, into a reality. Researchers led by Chalmers Univ. of Technology turbomachinery professor Tomas Grönstedt considered some of the major challenges to building one of these regional aircraft, including the need for compact heat exchangers that can keep hydrogen supercooled to –250°C during flight. This prevents what is called “boil off,” or the transition of the hydrogen into gas, which must be either re-liquified or vented to prevent raising the pressure in the hydrogen tank to a dangerous level.

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▲ Researchers led by Chalmers Univ. of Technology professor Tomas Grönstedt designed a new heat exchanger that preheats the fuel with heat from the exhaust gas and uses cold hydrogen to help cool the aircraft engines. Image courtesy of GKN Aerospace.

Insulating the tank with low-density foam or with a double-walled vacuum...