Fuel Cell Oxidant Supply Using Cabin Air Compressor Exhaust
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Solution Overview
Problem
Traditional emergency power units in aerospace face challenges with large, heavy thermal management systems that induce drag and difficulties in supplying oxidizing agents, particularly in lower power applications.
Innovation Solution
An oxidant supply system for fuel cells in emergency power units that utilizes cabin air compressor exhaust as the oxidant, with optional heat exchangers to regulate temperature, and integrates a thermal management system with dual heat transfer devices to manage heat efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional thermal management systems are used for fuel cells, then the fuel cell can function properly with temperature management, but the system becomes physically large, heavy, and induces drag on the aircraft
Solution Approach 1:
The patent combines the thermal management function with the oxidant supply function by using the same air supply system for both cooling the fuel cell and providing oxidant. The air supply system serves dual purposes: it removes heat from the fuel cell stack and simultaneously delivers oxygen for the electrochemical reaction, eliminating the need for separate thermal management components.
Solution Approach 2:
The air supply system is designed to perform multiple functions simultaneously: it acts as both a cooling system (thermal management) and an oxidant delivery system. The same air intake, filters, and distribution pathways serve both thermal regulation and chemical reaction support, making the system universal and reducing overall weight.
2Temperature
If traditional thermal management systems are used for fuel cells, then the fuel cell can function properly with temperature management, but the system becomes physically large and induces drag on the aircraft
Solution Approach 1:
The patent combines the thermal management function with the oxidant supply function by using the same air supply system for both cooling the fuel cell and providing oxidant. The air supply system serves dual purposes: it removes heat from the fuel cell stack and simultaneously delivers oxygen for the electrochemical reaction, eliminating the need for separate thermal management components.
Solution Approach 2:
The patent extracts the thermal management function from a separate system and integrates it into the oxidant supply system. By removing the need for dedicated cooling components (radiators, pumps, separate ducts), the design eliminates drag-inducing elements while maintaining effective temperature control through the unified air supply approach.
3Quantity of substance
If compressible fluids are supplied to the fuel cell in lower power applications, then the fuel cell can function, but it becomes difficult to supply the oxidizing agent
Solution Approach 1:
The patent adjusts operational parameters of the air supply system to optimize oxidant delivery across different power levels. By modifying flow rates, pressure settings, and air-to-fuel ratio parameters, the system maintains effective oxidant supply even in lower power applications where compressible fluid delivery is typically more difficult.
Solution Approach 2:
The system incorporates feedback mechanisms that monitor power demand and automatically adjust oxidant supply parameters. Sensors detect fuel cell operating conditions and modulate air flow accordingly, ensuring adequate oxidant delivery across the full power range without manual intervention or complex external 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
Simplifies compressor design, reduces system weight and drag, and effectively supplies oxidizing agents at optimal temperatures, enhancing power generation efficiency and reducing the need for additional air scoops.
Implementation Method 1
a fuel cell system configured to generate power using a fuel and an oxidant
Implementation Method 2
a compressor configured to receive the oxidant and compress the oxidant upstream of the fuel cell
Implementation Method 3
a turbine downstream from the fuel cell to receive exhaust flow and operatively connected to the compressor to turn the compressor
Implementation Method 4
a heat exchanger can be included in the oxidant supply line upstream of the branch point configured to cool the cabin air compressor exhaust before the cabin air is diverted to the fuel cell and the cabin
Implementation Method 5
a thermal management system can be in thermal communication with the fuel cell system to divert heat from the fuel cell system to the thermal management system
Data Source
AI summary
In accordance with at least one aspect of this disclosure, an emergency power unit system for an aircraft includes a fuel cell system configured to generate power using a fuel and an oxidant, and an oxidant supply system fluidly connected to the fuel cell system to supply the oxidant to the fuel cell system via an oxidant supply line. The oxidant supply system is fluidly connected to an environmental control system of an aircraft.