Passive Ejector-Pump Refrigeration for Aircraft Electronics Cooling
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Solution Overview
Problem
Conventional refrigeration systems for cooling aircraft electronics are inadequate in 'loss-of-cooling' scenarios where ambient cooling is insufficient, particularly when cooling air is unavailable or too hot, and there is a need for improved systems that can efficiently manage higher temperature heat sources with lower temperature tolerance.
Innovation Solution
A refrigeration system utilizing a main flow circuit with a heat input, passive pump, condenser, and cooling branch, which employs waste heat from aircraft systems to drive an ejector pump and generate flow through a cooling branch, providing cooling to aircraft electronics without a compressor, using wafer heat exchangers with adhesive surfaces for efficient heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional refrigeration systems are used for cooling aircraft electronics, then cooling can be provided under normal conditions, but the system becomes inadequate in loss-of-cooling scenarios where ambient cooling is insufficient
Solution Approach 1:
The system dynamically switches between ambient cooling mode and active refrigeration mode based on thermal conditions. The refrigeration system activates only when ambient cooling is insufficient, providing adaptive reliability across different operating scenarios.
Solution Approach 2:
The system uses waste heat from aircraft systems to drive the refrigeration cycle, making the system self-sufficient by utilizing available thermal energy resources rather than requiring external power inputs.
2Productivity
If a compressor is used in the refrigeration system, then refrigerant circulation can be maintained, but the system complexity and energy consumption increase
Solution Approach 1:
The patent replaces the traditional mechanical compressor with a thermally-driven refrigeration cycle that uses waste heat to circulate refrigerant. This substitution eliminates complex mechanical moving parts while maintaining refrigeration functionality.
Solution Approach 2:
The compressor component is extracted and removed from the system entirely. The refrigeration cycle is redesigned to function without this complex mechanical element, simplifying the overall system architecture.
3Use of energy by moving object
If waste heat from aircraft systems is utilized to drive the refrigeration cycle, then energy efficiency is improved, but the system requires specific thermal conditions to operate
Solution Approach 1:
The system converts waste heat, which would otherwise be discarded, into a useful resource to drive the refrigeration cycle. This transforms a thermal byproduct into the driving force for cooling, improving overall energy efficiency.
Solution Approach 2:
The refrigeration system serves multiple functions: it provides cooling when ambient conditions are insufficient and simultaneously utilizes waste heat that would otherwise be wasted. The system adapts to different thermal environments by switching between cooling modes.
4Loss of energy
If wafer heat exchangers with adhesive surfaces are used, then heat transfer efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The wafer heat exchangers use phase change materials that undergo color or state changes during phase transitions, enhancing heat transfer visibility and efficiency. The adhesive surfaces ensure consistent thermal contact.
Solution Approach 2:
The system changes the physical state parameters of the refrigerant through phase transitions in the wafer heat exchangers. The adhesive surfaces maintain optimal thermal contact parameters for efficient heat transfer.
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 provides additional cooling beyond ambient flow without a compressor, leveraging waste heat to efficiently cool aircraft electronics to desired temperatures, offering higher efficiency and local cooling capabilities, especially in scenarios where ambient cooling is insufficient.
Implementation Method 1
a heat input disposed in the main flow circuit and configured to receive heat and transfer the heat to the refrigerant in the main flow circuit
Implementation Method 2
a passive pump disposed in the main flow circuit downstream of the heat input configured to receive the heated refrigerant flow from the heat input and to use the heated refrigerant flow to generate a vacuum at a pump port
Implementation Method 3
The condenser can be configured to receive heat from the heated refrigerant flow and reject heat to cool the heated refrigerant flow
Implementation Method 4
at least one expander can be disposed in the cooling branch between the cooling branch inlet and the one or more cooling modules. The expander can be configured to receive the partially cooled refrigerant flow and cause expansion cooling
Implementation Method 5
The one or more cooling modules can be in thermal communication with one or more aircraft electronics, for example
Data Source
AI summary
A refrigeration system can include a main flow circuit configured to flow a refrigerant therethrough and a heat input disposed in the main flow circuit and configured to receive heat and transfer the heat to the refrigerant in the main flow circuit to output heated refrigerant flow. The system can include a passive pump disposed in the main flow circuit downstream of the heat input configured to receive the heated refrigerant flow from the heat input and to use the heated refrigerant flow to generate a vacuum at a pump port and a condenser disposed in the main flow circuit downstream of the passive pump for receiving flow from the passive pump. The condenser can be configured to receive heat from the heated refrigerant flow and reject heat to cool the heated refrigerant flow to output partially cooled refrigerant flow. An outlet of the condenser can be upstream of the heat input.