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Okay this relates to my project build here:-

http://www.overclock.net/t/1346823/subambient-full-submersion-phase-change-cooled-pc

But I think this may be the best place to ask this question as it essentially relates to phase change.

My project is basically a submerged pc where the liquid cools by phase changing....very much like the Novec 3m 7000 builds except hopefully at lower temperatures.

I'm now at point where I'm working on the heat sink for the cpu.....I'm not just using the IHS as the heat density would be too great so I'm using a solid copper 1u server heat sink to spread the heat out and this will also act as the evaporation plate.

http://www.akasa.co.uk/update.php?tpl=product/cpu.product.tpl&no=181&type=CPU%20coolers&type_sub=Low%20Profile&model=AK-CCE-7107BS

But I'm not sure the best way to go about it and was hoping for some advice from you guys as this is essentially a phase change evaporation plate.

I originally intended to remove the fan and cut off the fins to produce a flat plate 8.5cm x 8.5cm thinking the fins may hinder the cooling by trapping gas generated...they are 8mm tall with a spacing of 1.5 to 2 mm.

I also intended to try and coat the plate with a coating that would promote nucleation...Novec builds noted a X15 increase in cooling by using a granular coating of sub 10 micron diamond dust adhered to the surface.

I was hoping to copy that coating using as thin a layer as possible of thermal adhesive with alumina dust adhered to it....but I'm becoming uncertain that I could make the coating thin enough and may actually hinder the cooling effect.

I'm just not sure what would be the best to do....leave the fins on....perhaps even leave the fan on there as it would actively remove any trapped bubbles....or go ahead with the flat plate idea and home made coating??

Any help would be appreciated
Edited by technogiant - 10/1/13 at 10:15am