Movable Aircraft Fuel Cell Enclosure for External Cooling
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Solution Overview
Problem
Existing solutions for cooling high temperature fuel cells in aircraft emergency power units are inadequate, as they either fail to discharge sufficient heat energy or degrade aircraft performance, particularly in business aircraft where environmental control systems are limited and air intake systems compromise aerodynamics and increase size and weight.
Innovation Solution
An electrical power supply device with a fuel cell, dihydrogen generator, and cooling circuit housed in an enclosure that can be moved from an internal to an external position on the aircraft, utilizing outside air for passive cooling and incorporating a heat exchanger and fan for efficient heat dissipation, thereby allowing integration of high power fuel cells on small aircraft while ensuring safety by venting hydrogen outside.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an environmental control system (ECS) is used to discharge heat energy from the fuel cell, then the fuel cell can be cooled, but the cooling capacity is insufficient (only about 5 kWth) for high power fuel cells
Solution Approach 1:
The invention extracts the fuel cell from the internal aircraft environment and places it in an external enclosure that projects from the aircraft outer wall. This allows the fuel cell to be cooled directly by external air flow rather than relying on the limited internal ECS, thereby providing sufficient cooling capacity for high power applications.
Solution Approach 2:
The enclosure is made movable between an internal stowed position and an external deployed position. During flight, the enclosure deploys externally to maximize air flow for cooling. This dynamic positioning allows the system to adapt to different operational requirements while maintaining effective cooling.
2Temperature
If a liquid cold source is used to cool the fuel cell, then adequate cooling can be provided, but such a cold source is not always available on board business aircraft
Solution Approach 1:
The system uses the aircraft's own flight through air as the cooling mechanism. The external enclosure captures kinetic energy and ambient air flow during flight to passively cool the fuel cell, eliminating the need for separate liquid cold sources or active cooling systems that would not be available on all aircraft.
3Temperature
If a system for taking in outside air with a scoop is used to cool the fuel cell, then sufficient heat energy can be discharged, but the system degrades aircraft performance by increasing drag and weight
Solution Approach 1:
The cooling function is merged with the fuel cell enclosure structure itself. The enclosure serves dual purposes: housing the fuel cell and acting as the cooling intake structure. By integrating these functions, separate scoop structures are eliminated, reducing aerodynamic drag and weight.
Solution Approach 2:
The enclosure dynamically deploys only when needed for cooling during flight operations. When not in use, it remains stowed within the aircraft outer wall, presenting minimal aerodynamic resistance. This on-demand deployment minimizes drag during nominal operation while providing adequate cooling when the fuel cell is active.
4Reliability
If the fuel cell is integrated inside the aircraft, then safety is improved by containing hydrogen, but adequate cooling and hydrogen discharge become difficult
Solution Approach 1:
The system segments the hydrogen management functions: the fuel cell operates internally within the aircraft where safety is maintained through controlled containment, while the exhaust discharge function is routed externally through the movable enclosure. This separation allows both safe internal operation and effective external heat dissipation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively cools high temperature fuel cells, integrates high power fuel cells on small aircraft, and enhances safety by preventing dihydrogen leakage into the aircraft, while maintaining aerodynamic performance.
Implementation Method 1
a cooling circuit for cooling the fuel cell and associated with at least one heat exchanger
Implementation Method 2
when the enclosure is deployed into the second position, air from outside the aircraft serves to cool it, and thus provide passive regulation of the temperature of the components of the device
Data Source
AI summary
An electrical power supply device in an aircraft, the device including an enclosure, the enclosure containing at least: a fuel cell; a dihydrogen generator; a gas feed circuit connecting the dihydrogen generator to the anode of the fuel cell; an oxygen feed device feeding the cathode of the fuel cell; and a cooling circuit of the fuel cell associated with at least one heat exchanger; wherein the enclosure is mounted on an actuator system, the actuator system being configured to move the enclosure from a first position in which the enclosure is housed inside an outer wall of the aircraft, to a second position in which the enclosure projects from the outer wall.