Cryogenic Fuel Cell Air Feed Using Liquid Oxygen Pressurization
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Solution Overview
Problem
The widespread adoption of fuel cells in aerospace has been hindered by the reliance on bulky and energy-intensive auxiliary devices, particularly compressors, which affect mass and energy consumption.
Innovation Solution
A fuel cell system utilizing a cryogenic storage tank, heat exchange system, and liquid pumps to efficiently manage cryogenically cooled liquid fuel and oxygen, leveraging ambient heat and pressure to enhance efficiency, reducing the need for energy-intensive compression and enabling smaller system dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If compressors are used to pressurize oxygen containing gas for fuel cell operation, then fuel cell efficiency is improved, but system weight and energy consumption increase
Solution Approach 1:
The patent replaces the mechanical compressor system with a thermal field-based solution. The cryogenically cooled liquid fuel serves as a cooling medium to condense oxygen containing gas into liquid, which is then pressurized using a liquid pump and vaporized to produce pressurized oxygen gas for the fuel cell. This substitution eliminates the need for heavy mechanical compressors while achieving the required pressurization.
Solution Approach 2:
The patent utilizes phase transitions of oxygen containing gas (gas → liquid → gas) to achieve pressurization. The gas is condensed into liquid through heat exchange with cryogenically cooled fuel, pumped in liquid phase, and then vaporized to produce pressurized oxygen gas. This phase transition approach enables pressurization without mechanical compressors.
2Productivity
If compressors are used to pressurize oxygen containing gas, then fuel cell efficiency is improved, but energy consumption increases
Solution Approach 1:
The patent replaces the energy-intensive mechanical compression process with a thermal process using cryogenically cooled liquid fuel. The cooling effect of the liquid fuel condenses oxygen containing gas, which is then pressurized using a liquid pump (requiring less energy than gas compression) and vaporized to produce pressurized oxygen gas, significantly reducing overall energy consumption.
Solution Approach 2:
The patent converts the cold temperature (lack of heat) of the cryogenically cooled liquid fuel, which would otherwise be wasted, into a useful cooling resource. This cold energy is used to condense oxygen containing gas, enabling the entire pressurization process without requiring external compressors or additional energy input.
3Quantity of substance
If cryogenically cooled liquid fuel is used, then energy density is improved, but available cold energy requires management
Solution Approach 1:
The patent converts the cold energy of the cryogenically cooled liquid fuel into a useful resource for condensing oxygen containing gas. The liquid fuel absorbs heat from the oxygen containing gas during heat exchange, causing the gas to condense into liquid form. This approach eliminates waste heat and utilizes the cold energy for a productive function in the system.
Solution Approach 2:
The cryogenically cooled liquid fuel serves multiple functions: it provides fuel for the fuel cell, acts as a cooling medium for condensing oxygen containing gas, and enables pressurization through the phase transition process. This multi-functionality maximizes the utility of the cryogenic fuel and reduces the need for separate auxiliary 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
The system achieves improved energy efficiency and reduced weight by utilizing ambient heat and pressure, allowing for a more compact and efficient fuel cell operation, particularly suitable for aerospace applications.
Implementation Method 1
The heat exchange system is configured to heat fuel coming from the fuel inlet and feeding heated fuel to the fuel outlet
Implementation Method 2
The system thus effectively allows absorbing ambient heat, which causes a net flow of energy into the system
Implementation Method 3
cool oxygen containing gas from the gas inlet using fuel from the fuel inlet, thereby condensing at least part of said gas into a liquid
Implementation Method 4
By sufficiently cooling the oxygen containing gas, at least a part of the gas is condensed into a liquid, which also contains oxygen
Implementation Method 5
A first liquid pump is provided to increase the pressure of the oxygen containing liquid
Implementation Method 6
This heating step allows the oxygen containing liquid to evaporate at a relatively high pressure, thereby thus creating a pressurized oxygen containing gas
Data Source
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AI summary
The invention relates to a fuel cell system for increasing the efficiency of a fuel cell and auxiliary devices. The system uses a cryogenic fuel to increase the density of an incoming stream of air. The denser stream can be pumped or compressed more efficiently in the denser state. Density is increased using a heat exchange system. It is proposed to condense the stream of air, and optionally to perform cryogenic separation. The invention also relates to method applying these steps.