Abstract
Hydrogen-powered airplanes have recently attracted a revitalized push in
the aviation sector to combat CO2 emissions. However, to also reduce, or
even eliminate, non-CO2 emissions and contrails, the combination of
hydrogen with all-electric solutions is undoubtedly the best option to
move toward the ambitious goal of climate-neutral aviation. Another
important design choice is to store hydrogen cryogenically in its liquid
form (LH2) to reduce space occupation compared to storage as compressed
gas. However, the LH2 fuels cannot be utilized directly in fuel cells.
It needs to be brought from liquid to a gas at about 350 K, where large
amounts of heat must be added. Thus, a synergy can be made from this
otherwise wasted cryogenic refrigeration power where superconducting
machines (SCMs) and cold power electronics (CPE) are low-hanging fruits
that could lead to radical space and weight reductions onboard the
aircraft. These opportunities can be realized without having to pay the
price, nor the volume occupation and mass needed for the cooling ability
usually needed to achieve these extraordinary performances. In fact,
this ground-breaking synergy makes cryogenic energy conversion relevant
in a whole new way for aviation. The SCMs’ more than five times higher
power densities than their conventional counterparts are exceptionally
significant. This article introduces the recently proposed cryo-electric
drivetrain initiatives and explores the opportunities of using direct
hydrogen cooling as a potential heating solution to enhance the overall
performance and scalability of zero-emission propulsion systems in
future regional aircraft.