Reversible PEM Fuel Cell APU for Quiet Carbon-Free Aircraft Power

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Solution Overview

Problem

Auxiliary power units (APUs) in vehicles, particularly aircraft, rely on fossil fuel-based energy sources, which are environmentally unfavorable and produce noise, and there is a need for a more sustainable and quiet power solution when primary engines are off.

Innovation Solution

A system utilizing a reversible proton exchange membrane (PEM) fuel cell stack that operates in dual modes: electrolysis mode to generate hydrogen from water for storage and fuel cell mode to generate electricity from hydrogen, integrated with a hydrogen storage unit and electrical bus, allowing for clean and quiet power generation without fossil fuels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a fossil fuel-based APU is used to provide electricity when the engine is off, then power supply is ensured, but environmental pollution and noise increase

Engineering Contradiction:
Improveenergy source cleanlinessVSAvoidenvironmental pollution and noise
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The system changes the energy source parameter from fossil fuel to hydrogen, fundamentally altering the chemical composition and combustion characteristics to eliminate harmful emissions and reduce noise

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the conventional mechanical combustion engine with a fuel cell electrochemical system, substituting mechanical energy conversion with electrochemical energy conversion to achieve cleaner and quieter operation

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If a reversible fuel cell stack is used to generate hydrogen through electrolysis and then generate electricity through combustion, then a closed-loop hydrogen system is achieved, but system complexity increases

Engineering Contradiction:
Improvedual-mode operation capabilityVSAvoidsystem structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The reversible fuel cell stack is designed to perform multiple functions: electrolysis mode for hydrogen generation and fuel cell mode for electricity generation, allowing a single device to replace what would traditionally require separate systems

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the electrolyzer and fuel cell into a single reversible stack, merging two previously separate functions into one integrated system that can operate in either mode depending on system needs

Inventive Principle:
Principle #5Merging (Combining)

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

The system provides a 100% carbon-free, environmentally friendly power solution for vehicles, enabling quiet operation and instant startup, with hydrogen as the only byproduct, reducing noise and environmental impact.

Implementation Method 1

receiving electrical energy from a vehicle engine by an electrical bus, providing electricity from the bus and water from a water tank to a reversible fuel cell stack operating in an electrolysis mode to generate hydrogen

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Implementation Method 2

providing hydrogen from the hydrogen storage unit to the reversible fuel cell stack operating as an electricity generator to generate electricity

Methodology Applied
Scientific EffectFuel cell electrochemical reaction: Fuel Cell

Implementation Method 3

transferring hydrogen from the hydrogen tank to a hydrogen combustion electricity generator, and providing the generated electricity from the hydrogen combustion electricity generator to the electrical bus

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4254573A1Hydrogen powered auxiliary power unit
Publication Date: 2023.10.04 HONEYWELL INTERNATIONAL INC
  • EP4254573A1 patent drawingFigure 1
  • EP4254573A1 patent drawingFigure 2
  • EP4254573A1 patent drawingFigure 3

AI summary

A system includes a reversible proton exchange membrane (PEM) fuel cell stack configured to receive oxygen and to controllably receive water and hydrogen, an electrical bus for coupling to a vehicle engine to receive electricity, the electrical bus coupled to the reversible fuel cell stack to controllably receive electricity from the fuel cell stack and provide electricity to the reversible fuel cell stack, and a hydrogen storage unit coupled to controllably receive hydrogen from the fuel cell stack, provide hydrogen to the fuel cell stack, and to provide hydrogen to a hydrogen gas powered electricity generator unit to couple to the electrical bus.