An artist’s rendering of a 100-passenger hybrid-electric aircraft that uses hydrogen as fuel. (Courtesy of Dr. Jonathan Gladin)
Promising cryogenic design could transform sustainable aircraft propulsion by 2035
Researchers at the FAMU-FSU College of Engineering have engineered a practical liquid hydrogen storage and delivery system that brings zero-emission aviation significantly closer to reality. Their innovative design addresses multiple engineering challenges simultaneously, enabling hydrogen to serve as both a clean fuel and an integrated cooling medium for critical power systems in next-generation electric aircraft.
Legitimate Design for Sustainable Flight
The comprehensive study, published in Applied Energy, introduces a scalable system specifically designed for 100-passenger hybrid-electric aircraft. The new design integrates hydrogen fuel cells with hydrogen turbine-driven superconducting generators, demonstrating how liquid hydrogen can be efficiently stored, safely transferred and strategically used to cool onboard systems during all flight phases.
“Our goal was to create a single system that handles multiple critical tasks: fuel storage, cooling and delivery control,” said Wei Guo, professor in the joint college’s Department of Mechanical Engineering and corresponding author of the study. “This design lays the foundation for real-world hydrogen aviation systems.”
Solving Aviation’s Hydrogen Challenge
Hydrogen emerges as aviation’s most promising clean fuel alternative, packing more energy per kilogram than conventional jet fuel while producing zero carbon dioxide emissions. However, its ultra-low density requires storage as a super-cold liquid at –253°C, presenting significant engineering challenges for aircraft applications.
The FAMU-FSU team tackled this challenge through comprehensive system-level optimization, developing an innovative approach that goes beyond traditional tank design. They introduced a new gravimetric index—the ratio of fuel mass to total fuel system mass—that accounts for all system components including hydrogen fuel, tank structure, insulation, heat exchangers, circulation devices and working fluids.
Achieving Breakthrough Efficiency
Through methodical optimization of key design parameters such as vent pressure and heat exchanger dimensions, the team identified a configuration achieving a remarkable gravimetric index of 0.62. This means 62% of the system’s total weight consists of usable hydrogen fuel—a significant advancement over conventional designs that could accelerate commercial hydrogen aviation deployment.
Innovative Thermal Management Integration
The system’s dual-function approach represents a paradigm shift in aircraft design. Rather than installing separate cooling systems, the innovative design routes ultra-cold hydrogen through strategically positioned heat exchangers that remove waste heat from superconducting generators, motors, cables and power electronics. This thermal integration process naturally preheats the hydrogen to optimal temperatures for fuel cell and turbine operation.
Pump-Free Delivery Innovation
Delivering liquid hydrogen throughout aircraft presents unique challenges, as mechanical pumps add weight, complexity and potential failure points under cryogenic conditions. The research team developed an elegant pump-free system that utilizes tank pressure regulation to control hydrogen flow.
The system employs two pressure control methods: injecting hydrogen gas from high-pressure cylinders to increase pressure and venting hydrogen vapor to decrease it. Advanced feedback loops connect pressure sensors to the aircraft’s power demand profile, enabling real-time pressure adjustments that ensure correct hydrogen flow rates across all flight phases.
Meeting Peak Power Demands
Simulations demonstrate the system can deliver hydrogen at rates up to 0.25 kilograms per second—sufficient to meet the 16.2-megawatt electrical demand during takeoff or emergency go-around procedures, critical phases requiring maximum power output.
Staged Thermal Integration Strategy
The heat exchangers operate in a carefully orchestrated sequence that maximizes efficiency while minimizing hardware complexity. As hydrogen flows through the system, it first cools high-efficiency cryogenic components like high-temperature superconducting generators and cables. Subsequently, it absorbs heat from higher-temperature components, including electric motors, motor drives and power electronics, before reaching optimal fuel cell inlet conditions.
“Previously, people were unsure about how to move liquid hydrogen effectively in an aircraft and whether you could also use it to cool down the power system component,” Guo explained. “Not only did we show that it’s feasible, but we also demonstrated that you needed to do a system-level optimization for this type of design.”
Advancing Toward Commercial Reality
While this newest study focused on design optimization and system simulation, the research team is preparing for the crucial next phase: experimental validation. Guo and his team plan to construct a prototype system and conduct comprehensive testing at FSU’s Center for Advanced Power Systems, a critical step toward commercialization.
The project operates within NASA’s Integrated Zero Emission Aviation program, a collaborative initiative bringing together leading institutions across the United States to develop comprehensive clean aviation technologies. Partner universities include Georgia Tech, Illinois Institute of Technology, University of Tennessee and University at Buffalo, with FSU leading hydrogen storage, thermal management, and power system design efforts.
Research Team Excellence
At the joint college, key contributors include graduate student Parmit S. Virdi and professors Lance Cooley, Juan Ordóñez, Hui Li and Sastry Pamidi, along with additional faculty experts specializing in cryogenics, superconductivity and advanced power systems.
Supporting Innovation in Clean Aviation
This transformative research receives support from NASA through the University Leadership Initiative, which empowers U.S. universities to receive NASA funding while leading their own research teams and setting research agendas that support the agency’s Aeronautics Research Mission Directorate and Strategic Implementation Plan.
Guo’s research was conducted at the joint-college affiliated and FSU-headquartered National High Magnetic Field Laboratory, which the National Science Foundation and the State of Florida support. This highlights the collaborative nature of this groundbreaking work.
Future Impact on Sustainable Transportation
This research positions the FAMU-FSU College of Engineering and Florida State University as a leader in the global race toward zero-emission aviation. Potential applications extend beyond aircraft to other transportation sectors that require efficient hydrogen storage and thermal management solutions.
Editor’s Note: This article was edited with a custom prompt for Claude Sonnet 4, an AI assistant created by Anthropic. The AI optimized the article for SEO discoverability, improved clarity, structure and readability while preserving the original reporting and factual content. All information and viewpoints remain those of the author and publication. This disclosure is part of our commitment to transparency in our editorial process. Last edited: May 29, 2025.
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