Intelligent Energy has introduced its latest innovation in drone fuel cell technology with the launch of the high-temperature IE-FLIGHT™ fuel cell system, based on the company’s patented cooling technology.
In a newly released white paper, the company explores the potential of the IE-FLIGHT proton-exchange membrane (PEM) fuel cell systems to tackle the challenge of achieving zero-emission flight in drones and unmanned aerial vehicles (UAVs).
The study highlights the critical need for large and heavy thermal management systems to dissipate the heat generated by fuel cells, a significant challenge for fuel cell-powered aircraft due to the added weight and drag from large heat exchangers.
The IE-FLIGHT fuel cell system addresses this issue by reducing the size of onboard heat exchangers, minimizing aerodynamic drag, and maintaining high gravimetric power density while utilizing the advantages of high-current density LT-PEM fuel cells.
Initial modeling results presented in the white paper indicate that for a 9-passenger aircraft, the block fuel could be reduced by up to 5% with the IE-FLIGHT fuel cell system’s high-temperature architecture compared to conventional systems, due to reduced propulsion drag. In future aircraft designs, where propulsion drag is predicted to be a greater proportion of the overall aerodynamic drag, that fuel saving could increase.
These findings support the viability of hydrogen fuel cell powertrains for future zero-emission aircraft, including eVTOL, sub-regional, and regional markets, as well as hydrogen fuel cell-powered APUs within future hydrogen combustion-powered wide-body aircraft.
IE-FLIGHT Fuel Cell System
Advantages
Intelligent Energy’s high-temperature fuel cell system architecture for the IE-FLIGHT system, designed for eVTOL, CS-23, and CS-25 class aircraft propulsion and APUs, offers several benefits:
- Reduced heat exchanger size
- Lower aerodynamic drag
- High gravimetric power density
The system achieves higher thermal efficiency by compressing cathode exhaust fluids between the fuel cell stack and the heat exchanger, increasing pressure and temperature within the heat exchanger. This allows for a size reduction compared to other fuel cell system heat exchangers.
Modeling Summary
- Use case: The assessment focused on a 9-seater aircraft flying a 100nm mission at a cruise altitude of 5,000 feet and a speed of 140 knots.
- Optimization: The system was optimized for drag, mass, and efficiency to achieve an ideal aircraft solution.
- Key modeling trade: A 1% change in drag leads to a 1% change in block fuel.
Results
Smaller heat exchanger
The high-temperature architecture results in a 23% reduction in heat exchanger area, leading to lower drag.
Block fuel reduction
Preliminary analysis shows that the EC-HT architecture will meet the 1.5kW/kg power density target and could deliver a block fuel improvement of up to 5% for the analyzed mission compared to conventional fuel cell systems.
Operational efficiency improvement
The Evaporatively Cooled High-Temperature (EC-HT) architecture can be dynamically tuned to optimize efficiency, eliminating the need for oversized heat exchangers for worst-case conditions.
Higher cruise speed
Lower drag with EC-HT architecture allows for higher cruise speeds with reduced fuel penalties.
Future aircraft benefits
As propulsion drag is expected to increase in new aircraft designs, the reduced drag from EC-HT architecture will offer additional benefits to the industry.
eVTOL payload and range benefits
Compared to future battery performance projections, the IE-FLIGHT fuel cell system provides higher specific energy, leading to greater payload and extended range, enhancing ROI potential for operators.
Ongoing trade studies are focusing on optimizing system component selection, including two-stage compressor performance, heat exchanger configuration, and turbine size, across various mission and altitude conditions.
The IE-FLIGHT system now enters the next phase of design, intended for fixed-wing engine replacements and new eVTOL airframe applications, through collaboration with partners, customers, and integrators. Intelligent Energy plans to incorporate this high-temperature architecture into future IE-FLIGHT fuel cell system products.
