In a major step toward zero-emission aviation, researchers at the FAMU-FSU College of Engineering have developed a new way to store and deliver liquid hydrogen that could power the aircraft of the future.
Their innovative system not only uses hydrogen as a clean fuel but also as a built-in coolant for the plane’s power systems—tackling several engineering challenges at once.
Published in the journal Applied Energy, the study focuses on designing a system for a 100-passenger hybrid-electric aircraft.
This aircraft would run on both hydrogen fuel cells and hydrogen-powered superconducting generators, which need to stay extremely cold to work properly.
The researchers created a system that efficiently stores liquid hydrogen, safely delivers it throughout the aircraft, and uses it to cool vital onboard components—all while meeting the plane’s power demands during takeoff, cruising, and landing.
Hydrogen is seen as a promising clean fuel because it holds more energy per kilogram than jet fuel and releases no carbon dioxide when used.
But it’s tricky to work with—it must be stored as a liquid at an ultra-cold temperature of –253°C. That adds major design challenges, especially in an aircraft where space and weight are tightly limited.
To solve this, the research team carefully optimized the design of the hydrogen tank and the systems around it. Instead of only focusing on the tank itself, they looked at the entire fuel system—tank structure, insulation, pumps, pipes, heat exchangers, and more.
They created a new measurement called the gravimetric index, which compares the weight of usable hydrogen fuel to the total weight of the full system. Their best design achieved an index of 0.62, meaning 62% of the system’s total weight is usable fuel—much better than traditional systems.
A standout feature of the design is how it uses the cold hydrogen for thermal management. As the hydrogen flows through the system, it passes through a series of heat exchangers. First, it cools key cryogenic components like superconducting cables and generators.
Then, it absorbs heat from warmer parts, such as electric motors and power electronics. Finally, just before entering the fuel cells and turbines, it is warmed to the right temperature to be used as fuel.
Instead of using mechanical pumps to move the hydrogen—an option that adds weight and risk—the system controls the flow using tank pressure. This is adjusted in real-time based on flight needs using pressure sensors and simple valves. Simulations show it can deliver enough hydrogen to meet high power demands, such as during takeoff.
This all-in-one system proves that hydrogen can be a clean, efficient, and practical solution for future aircraft. As Professor Wei Guo put it, they didn’t just show it was possible—they showed how to do it well.
