Subambient Boiling Coolant Cooling for High-Flux Electronics
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Solution Overview
Problem
Existing cooling methods for high-power electronic components, such as phased array antennas and future computational circuits, are inadequate due to the large size, weight, and power consumption of refrigeration units, and fail to effectively remove high flux heat loads using conventional coolants like fluorinerts.
Innovation Solution
A method and apparatus that utilize a coolant at subambient pressure, such as pure water or methanol, to boil and vaporize, absorbing heat from heat-generating structures, with a system that includes a subambient cooling system where the coolant is reduced to a pressure lower than ambient, allowing it to boil at a temperature below the structure's temperature, enhancing heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If refrigeration units are used to cool high-power electronics, then cooling capacity is improved, but device size, weight, and power consumption increase significantly
Solution Approach 1:
The patent utilizes the phase transition of water from liquid to vapor (boiling) at subambient pressure to absorb heat from electronic components. By reducing the pressure below atmospheric levels, water boils at temperatures below 100°C, enabling efficient heat removal through latent heat of vaporization without requiring heavy refrigeration machinery
Solution Approach 2:
The system changes the pressure parameter of the coolant (water) from ambient to subambient levels. This parameter change fundamentally alters the boiling point of water, allowing it to operate as an effective coolant at lower temperatures and eliminating the need for complex compression and expansion mechanisms found in traditional refrigeration systems
2Reliability
If conventional coolants like fluorinerts are used, then electrical insulation is maintained, but heat transfer performance is insufficient for high flux heat loads
Solution Approach 1:
The patent changes the pressure parameter of water to subambient levels, which lowers the boiling point and enhances the heat transfer coefficient during phase change. This allows water to achieve superior heat transfer performance compared to fluorinerts while maintaining adequate electrical insulation through proper system design and voltage clearance
Solution Approach 2:
The system exploits the phase transition of water at subambient pressure to achieve high heat flux removal. The latent heat of vaporization during boiling provides extremely efficient heat transfer, far exceeding the capabilities of single-phase fluorinert coolants, while the brief contact time and vaporization process maintain electrical insulation
3Productivity
If water is used as coolant at ambient pressure, then heat transfer efficiency is improved, but electrical shorts occur due to low electrical resistivity
Solution Approach 1:
The patent utilizes the phase transition of water to vapor during boiling at subambient pressure. This phase change creates a natural electrical insulation barrier as the vapor phase has high electrical resistivity, allowing water to function as both an efficient heat transfer medium and an electrical insulator simultaneously
Solution Approach 2:
By changing the pressure parameter to subambient levels, the system alters the thermodynamic properties of water, including its boiling point and electrical characteristics. The phase transition at controlled pressure enables water to maintain electrical insulation while achieving superior 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 approach allows for efficient removal of large heat amounts from densely-packed electronics, reducing the need for large refrigeration units and minimizing power consumption, while maintaining high electrical resistivity to prevent electrical shorts.
Implementation Method 1
reducing a pressure of the coolant to a subambient pressure at which the coolant has a boiling temperature less than a temperature of the heat-generating structure, and bringing the heat-generating structure and the coolant at the subambient pressure into contact with one another, so that the coolant boils and vaporizes to thereby absorb heat from the heat-generating structure
Implementation Method 2
the coolant boils and vaporizes to thereby absorb heat from the heat-generating structure
Implementation Method 3
the coolant boils and vaporizes to thereby absorb heat from the heat-generating structure
Implementation Method 4
In a more particular embodiment the coolant is either pure water or pure methanol with an electrical resistivity level of greater than one million Ohms-cm
Data Source
Figure 1A~2
Figure 3A~3D
Figure 4A~4B
AI summary
According to one embodiment of the invention, a method is provided for cooling heat-generating structure disposed in an environment having an ambient pressure. The heat-generating structure includes electronics. The method includes providing a coolant, reducing a pressure of the coolant to a subambient pressure at which the coolant has a boiling temperature less than a temperature of the heat-generating structure, and bringing the heat-generating structure and the coolant at the subambient pressure into contact with one another, so that the coolant boils and vaporizes to thereby absorb heat from the heat- generating structure. In a more particular embodiment the coolant is either pure water or pure methanol with an electrical resistivity level of greater than one million Ohms-cm. Further, in another particular embodiment the method includes filtering the coolant to maintain its purity above a particular level.