Fuel Cell Power Source for Extended UAS Flight Duration
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Solution Overview
Problem
The endurance of small unmanned air systems (UAS) is limited by the low energy density of batteries, restricting flights to visual line of sight operations, necessitating higher energy density and lighter weight power sources for extended flight capabilities.
Innovation Solution
A fuel cell-based power source is developed, incorporating a hydrogen generator and a PEM fuel cell stack, with a closed-loop hydrogen system and water exchanger to recycle water vapor, enhancing energy density while minimizing weight, and a power management system to control airflow and temperature for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If batteries are used as power source, then the system is simple and reliable, but the energy density is low and flight duration is limited
Solution Approach 1:
The patent changes the energy storage parameter from chemical batteries to fuel-based energy storage, enabling extended flight duration while maintaining acceptable weight. The fuel cell system converts chemical energy from hydrogen fuel directly to electrical energy, providing sustained power output for hours rather than minutes.
Solution Approach 2:
The power system is segmented into multiple components: fuel storage tanks, fuel cell stack, water exchanger, and power management system. This segmentation allows each component to be optimized independently for weight and efficiency while working together to achieve extended flight duration.
2Use of energy by moving object
If fuel cell system is implemented, then energy density and flight duration are improved, but the system weight and complexity increase
Solution Approach 1:
The water exchanger recycles water vapor from the fuel cell cathode output back to the fuel storage system, creating a closed-loop system. This self-service mechanism eliminates the need for additional water storage tanks and reduces overall system weight while maintaining fuel cell performance.
Solution Approach 2:
The fuel cell system serves multiple functions: primary power generation, water recycling, and thermal management. The cathode output serves dual purposes as both exhaust and water source for fuel regeneration, reducing the need for separate subsystems and lowering total weight.
3Duration of action of moving object
If fuel cell system is implemented, then energy density and flight duration are improved, but the device complexity increases
Solution Approach 1:
The water exchanger merges the water recycling function with the fuel storage system, combining what would otherwise be separate subsystems. This integration reduces the number of components and simplifies the overall system architecture while enabling extended flight duration.
Solution Approach 2:
The water vapor acts as an intermediary substance that transfers mass and energy between the fuel cell cathode and the fuel storage system. This intermediary mechanism enables the closed-loop water recycling without requiring complex mechanical pumping systems.
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 enables UAS to achieve flight times measured in hours instead of minutes, with a total weight under 55 lbs, and supports satellite communications, providing a reliable and efficient power source for extended operations.
Implementation Method 1
a fuel cell-based power source is developed, incorporating a hydrogen generator and a PEM fuel cell stack
Implementation Method 2
with a closed-loop hydrogen system and water exchanger to recycle water vapor
Implementation Method 3
water exchanger to recycle water vapor
Implementation Method 4
incorporating a hydrogen generator and a PEM fuel cell stack
Data Source
AI summary
An air system includes a fuselage, a motor supported by the fuselage, a propeller coupled to the motor, a fuel cell-based power generator supported by the fuselage and the motor, and a satellite communication system coupled to the fuel cell system. The generator includes a hydrogen generator, a fuel cell having an anode and a cathode, a cathode loop configured to provide oxygen to the cathode, an anode loop configured to provide hydrogen generated by the hydrogen generator to the anode, and an electrical connector coupled to the fuel cell to provide electricity generated by the fuel cell to the motor.