Editing Computer cooling (section)

===Liquid immersion cooling===
<!--Full immersion cooling links here-->
{{main|Server immersion cooling}}
[[File:Toby and the Mineral Oil Cooled Rig (4958369451).jpg|thumb|A computer immersed in mineral oil]]
Another growing trend due to the increasing heat density of computers, GPUs, FPGAs, and [[application-specific integrated circuit|ASIC]]s is to immerse the entire computer or select components in a [[thermal conduction|thermally, but not electrically, conductive]] liquid. Although rarely used for the cooling of personal computers,<ref>{{cite web|url=http://www.eppenga.com/photos/fluid-cooled-pc/liquid-pc-technical.html|title=Liquid PC Technical – Eppenga Website|first=Ebo|last=Eppenga|website=eppenga.com|access-date=25 July 2014|archive-url=https://web.archive.org/web/20140812063836/http://www.eppenga.com/photos/fluid-cooled-pc/liquid-pc-technical.html|archive-date=12 August 2014|url-status=live}}</ref> liquid immersion is a routine method of cooling large power distribution components such as [[Distribution transformer|transformers]]. It is also becoming popular with data centers.<ref>{{cite web|url=http://www.datacenterknowledge.com/archives/2013/07/01/the-immersion-data-center/|title=The Immersion Data Center: The New Frontier of High-Density Computing|date=1 July 2013|access-date=25 July 2014|archive-url=https://web.archive.org/web/20140727084549/http://www.datacenterknowledge.com/archives/2013/07/01/the-immersion-data-center/|archive-date=27 July 2014|url-status=live}}</ref><ref name="facebook-immersion">{{cite web|url=http://www.datacenterknowledge.com/archives/2012/12/21/facebook-tests-immersion-cooling/|title=Facebook Tests Immersion Cooling|date=21 December 2012|access-date=25 July 2014|archive-url=https://web.archive.org/web/20140727102138/http://www.datacenterknowledge.com/archives/2012/12/21/facebook-tests-immersion-cooling/|archive-date=27 July 2014|url-status=live}}</ref> Personal computers cooled in this manner may not require either fans or pumps, and may be cooled exclusively by [[Thermosiphon|passive heat exchange]] between the computer hardware and the enclosure it is placed in.<ref name="facebook-immersion"/><ref>{{cite web|url=http://www.eppenga.com/photos/fluid-cooled-pc/liquid-cooled-pc.html|title=Liquid Cooled PC – Eppenga Website|first=Ebo|last=Eppenga|website=eppenga.com|access-date=25 July 2014|archive-url=https://web.archive.org/web/20140812065345/http://www.eppenga.com/photos/fluid-cooled-pc/liquid-cooled-pc.html|archive-date=12 August 2014|url-status=live}}</ref> A heat exchanger (i.e. [[heater core]] or radiator) might still be needed though, and the piping also needs to be placed correctly.<ref>{{Cite web|url=http://www.iceotope.com/the-science|archive-url=https://web.archive.org/web/20140728123429/http://www.iceotope.com/the-science|url-status=dead|title=Iceotope hardware case, note that 2 hot pipes are present in the plastic box holding the hardware (functioning as coolant reservoir), of which one -the hot pipe- is placed at the top, and the other -the cold one- at the bottom|archive-date=28 July 2014}}</ref>

The coolant used must have sufficiently low [[electrical conductivity]] not to interfere with the normal operation of the computer. If the liquid is somewhat electrically conductive, it may cause electrical shorts between components or traces and permanently damage them.<ref>Tom's Hardware – "[http://www.tomshardware.com/2006/01/09/strip_out_the_fans/ Strip Out The Fans]", 9 January 2006, presented as 11 web pages.</ref> For these reasons, it is preferred that the liquid be an insulator ([[dielectric]]) and not conduct electricity.

A wide variety of liquids exist for this purpose, including [[transformer oil]]s, synthetic single-phase and dual phase dielectric coolants such as [[3M]] [[Fluorinert]] or 3M Novec. Non-purpose oils, including cooking, motor and [[silicone oil]]s, have been successfully used for cooling personal computers.

Some fluids used in immersion cooling, especially hydrocarbon based materials such as mineral oils, cooking oils, and organic esters, may degrade some common materials used in computers such as rubbers, [[polyvinyl chloride]] (PVC), and [[thermal grease]]s. Therefore it is critical to review the material compatibility of such fluids prior to use. Mineral oil in particular has been found to have negative effects on PVC and rubber-based wire insulation.<ref>{{cite web|url=https://www.pugetsystems.com/submerged.php|title=Mineral Oil Cooled PC – Project Ready DIY Kit for the PC Enthusiast|website=pugetsystems.com|access-date=19 December 2018|archive-url=https://web.archive.org/web/20181215174126/https://www.pugetsystems.com/submerged.php|archive-date=15 December 2018|url-status=live}}</ref> Thermal pastes used to transfer heat to heatsinks from processors and graphic cards has been reported to dissolve in some liquids, however with negligible impact to cooling, unless the components were removed and operated in air.<ref>{{Cite web|url=https://www.youtube.com/watch?v=sSnGmAqQaFs|title=Parts from the Oil-cooled PC – Do they still work???|date=22 February 2018 |via=www.youtube.com|access-date=19 December 2018|archive-url=https://web.archive.org/web/20180226005901/https://www.youtube.com/watch?v=sSnGmAqQaFs|archive-date=26 February 2018|url-status=live}}</ref>

Evaporation, especially for 2-phase coolants, can pose a problem,<ref>{{Cite web|url=https://www.engineeredfluids.com/immersioncooling|title=Engineered Fluids {{!}} Single-Phase Immersion Cooling|website=Dielectric Coolants {{!}} United States {{!}} Engineered Fluids|language=en|access-date=2019-01-21|archive-url=https://web.archive.org/web/20190122043912/https://www.engineeredfluids.com/immersioncooling|archive-date=22 January 2019|url-status=live}}</ref> and the liquid may require either to be regularly refilled or sealed inside the computer's enclosure. Immersion cooling can allow for extremely low [[Power usage effectiveness|PUE]] values of 1.05, vs air cooling's 1.35, and allow for up to 100&nbsp;KW of computing power (heat dissipation, TDP) per [[19-inch rack]], as opposed to air cooling, which usually handles up to 23&nbsp;KW.<ref>{{Cite web|url=https://www.datacenterknowledge.com/power-and-cooling/five-reasons-data-center-liquid-cooling-rise|title=Five Reasons Data Center Liquid Cooling Is on the Rise|date=23 July 2018|website=Data Center Knowledge}}</ref>