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Stick computers in oil
Spring 2009
Engr 45
By,
Sergy Pretetsky &
Jeff Hitchcock
Why computers need cooling
• Greater conductivity at low temperatures
• Avoid critical failure
• Overheating= over stressing components
Common Computer cooling
• Air cooled heatsinks
• Water cooling
• Peltier cooling
• Phase change cooling
• Liquid nitrogen & Dry ice and acetone
Thermal properties(water vs. air)
• Volumetric Heat capacity (Jcm-3K-1)– Water - 4.186– Air - 0.001297
• Thermal conductivity (W/(m·K))– Water - 0.6– Air - 0.025
• Heat Transfer Coefficients– Water – 500-10,000 W/(m2K) – Air – 10-100 W/(m2K)
Thermal properties(water vs. oil)
• Volumetric Heat capacity (Jcm-3K-1)– Water - 4.186– Oil - ~2 (FAR more than air)
• Thermal conductivity (W/(m·K))– Water - 0.6– Oil - .15 (60 times more than air)
• Heat Transfer Coefficients– Water – 500-10,000 W/(m2K) – Oil – ?
The complete set up
The Tub
The Oil
The Computer submerged
The Overclocking test
Thermal paste test
ResultsLong term test
• Processing remained the same
• Problems– Plastics– Heat retention in oil
ResultsOverclocking Test
• With oil– no additional performance
• Old computer– possibly maxed out components– If we had new computer, could have pushed it further
ResultsThermal Paste test
• Out of 3 popular thermal pastes– 1 was dissolved away– 2 were unaffected
• @ RT– Possibly more degrading at running temps
Conclusion• With an old computer
– Didn’t help boost performance• Didn’t cause failure
What to do next time• Use a radiator to cool the oil• Keep power supply separate
Sources
• http://en.wikipedia.org/wiki/Specific_heat_capacity• http://en.wikipedia.org/wiki/Heat_transfer_coefficient• http://www.medwelljournals.com/fulltext/jeas/2006/495-4
99.pdf• http://www.mobil.com/USA-English/Lubes/PDS/glxxenpvl
momobil1_truck_suv_5w-30.pdf• http://www.engineeringtoolbox.com/thermal-conductivity-
d_429.html