Perfluorinated Coolant Immersion Cooling for Electronic Devices
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Solution Overview
Problem
Current cooling systems for supercomputers and data centers face inefficiencies due to high evaporative loss of expensive fluorocarbon-based liquid coolants, local boiling impairing heat transfer, and complex maintenance in sealed module structures, which hinder effective cooling of diverse electronic components and increase maintenance costs.
Innovation Solution
A cooling system utilizing a perfluorinated compound with a boiling point of 150 °C or more, low evaporation rate, and steam pressure of 1.0 kPa or less, integrated with a header and nozzle arrangement for forced circulation, ensuring efficient cooling and reduced evaporative loss in an open, unsealed structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fluorocarbon-based liquid coolant with boiling point of 100°C or less is used to utilize vaporization heat for cooling, then cooling efficiency is improved, but local boiling produces air bubbles forming insulation film which impairs heat transfer capacity
Solution Approach 1:
The patent changes the key parameter of the coolant from low-boiling-point fluorocarbon (100°C or less) to perfluorinated compound with high boiling point (150°C or more). This parameter change eliminates local boiling and insulation film formation while maintaining cooling effectiveness through high-temperature stability and sustained heat transfer capacity.
2Temperature
If fluorocarbon-based liquid coolant is used in open unsealed structure, then cooling performance is improved, but evaporative loss increases leading to frequent replenishment and high maintenance costs
Solution Approach 1:
The patent changes the volatility parameter of the coolant by selecting perfluorinated compounds with high boiling points (150°C or more) and low vapor pressures (1.0 kPa or less at 25°C). This parameter change dramatically reduces evaporative loss in open unsealed structures, eliminating frequent replenishment needs and reducing maintenance costs while preserving cooling performance.
3Temperature
If synthetic oil with high viscosity is used as liquid coolant, then cooling efficiency is improved, but maintenance work becomes extremely complicated due to difficulty of removing adherent oil
Solution Approach 1:
The patent changes the viscosity parameter of the coolant from high viscosity (synthetic oil) to low viscosity (perfluorinated compound). This parameter change enables easy removal of adherent coolant from electronic devices, transforming maintenance from extremely complicated to simple and efficient, while maintaining high cooling efficiency through effective heat transfer.
4Reliability
If cooling system uses sealed module structure, then coolant containment is improved, but maintenance and extraction of electronic devices becomes difficult
Solution Approach 1:
The patent extracts the coolant containment function from a sealed module structure, allowing the use of an open unsealed cooling bath. The perfluorinated compound's inherently low volatility provides sufficient containment without physical sealing, enabling easy device extraction and maintenance while maintaining coolant retention.
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 reduced evaporative loss and maintains high heat transfer efficiency, preventing local boiling and ensuring uniform cooling for densely packed electronic devices, while simplifying maintenance and reducing costs through the use of a stable, inert perfluorinated coolant.
Implementation Method 1
a liquid coolant contains a perfluorinated compound as a main component and having a liquid weight loss percentage of 1.5 % or less as determined by allowing 10 ml of the liquid coolant in a 10-ml measuring cylinder (opening diameter: 11.5 mm) to spontaneously evaporate under normal environment at a room temperature of 25 °C for 100 hours
Implementation Method 2
which directly cools the plural electronic devices by immersion of the electronic devices in the liquid coolant circulated in the open space
Implementation Method 3
When the liquid coolant is vaporized by heat generated by devices mounted in the electronic equipment, the vaporization takes heat (vaporization heat (latent heat)) from the devices which in turn are cooled
Implementation Method 4
the fluorocarbon-based liquid coolant may locally boil on the surface of a high-temperature device, producing air bubbles which form an insulation film
Data Source
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AI summary
To provide a cooling system which is adapted for reduction of evaporative loss of a liquid coolant and for efficient cooling of plural electronic devices densely accommodated in a cooling bath of a small volume. A cooling system 10 accommodates plural electronic devices 100 in an open space of a cooling bath 12 provided with an inlet port 14 and an outlet port 16 for a liquid coolant 13. The cooling system is configured to directly cool the electronic devices 100 by immersion of the electronic devices 100 in the liquid coolant 13 circulated in the open space. The liquid coolant 13 contains a perfluorinated compound as a main component. The liquid coolant is adapted to exhibit a liquid weight loss percentage of 1.5 % or less as determined by allowing 10 ml of the liquid coolant in a 10-ml measuring cylinder (opening diameter: 11.5 mm) to spontaneously evaporate under normal environment at a room temperature of 25 °C for 100 hours. Further, the liquid coolant 13 is also adapted to exhibit a steam pressure of 1.0 kPa or less at room temperature of 25 °C and/or a boiling point of 150 °C or more.