Which metal or material transfers heat the best 7

[musicians4um]

I am designing a liquid cooling system for a high performance computer, and I would like to know which metal transfers the MOST heat. The obvious answer seems to be either Copper or Aluminum, but i was wondering if there is anything that will transfer MORE heat than those two, that is economically feasible, and moderately malleable. It doesn’t necessarily HAVE to be metal. As long as it has a high melting point, yet a high heat transfer rate. Can anyone help me ?

Luis

 

[iainuts]

Try graphite, pyrolytic.

http://www.electronics-cooling.com/html/2001_august_techbrief.html

Or just Google 'graphite "thermal conductivity" ' or something like that.

Note the thermal conductivity of graphite in the direction parallel to the fiber direction is something like 3 - 5 times higher than copper.

 

[25362]

Add Silver to the list of malleable, high MP metals, possibly having the highest thermal and electrical conductivity among metals. But, of course, its economic feasibility is doubtful, to say the least.

Of the non-metals and excluding diamond, lamellar graphite an excellent thermal conductor (parallel to the lamellar planes), can even be improved as such by invading reactant species that change the amount of electrons from the conduction levels of graphite itself.

Follow iainuts' advice. Good luck.

 

[alexit]

In the metallic elements, anything with higher atomic mass but having the same free electrons would result in improved electrical/thermal conductivities...so copper, silver, gold or aluminum, gallium, indium, thallium. In non-metals the element structure becomes much more important: carbon can be very conductive, silicon is very insulative, lead and tin are conductive...

Alex

 

[weastman]

Aluminum is good. Copper is about 2X better. Graphite is a little over 4X better than aluminum (along the axis of the fiber). BUT, if I were you I would use a simple heat pipe which will provide orders of magnitude performance over metal conductive heat transfer, particular if your mass transfer is high.

 

[ko99]

I agree with weastman. Just a couple of notes:

If the location where heat is tranferred to the environment is remote from the heat source (say, >3X the source perimeter), heat pipes will outperform copper or graphite. And they can definitely cost less.

Remember the material conductivity is only one factor. Thermal losses at material interfaces can be greater than the loss through the material. In most liquid cooling systems, the thermal bottlenecks are the interfaces and the final heat transfer to air, and the difference between aluminum, copper, and heat pipes is negligible.

Good luck





ko

 

[musicians4um]

Well thanks for the input about heat pipes.

However, i haven’t seen too many heat pipes used for computer processors. i see a lot of them for video cards and things of that nature that need to be cooled also, but for processors you generally see a cooling fan, or a liquid cool system. How LARGE do you think a heat pipe system would have to be to make it work accurately and sufficiently?

one of the better things about liquid cooling systems that I have found is that they are able to cool items to a temperature lower than the air surrounding it. Ss with the heat pipe system i had on my video card, i literally noticed no difference. (However I don’t think my video card was heating up all that much.)

not only that, but I don’t think I would have the know how to accurately design a heat pipe system.

I would like to stay with the liquid cool systems because I have a little more experience in them.


NOW FOR THE NEXT QUESTION!

What kind of liquid would be the best inside a liquid cooling system? Generally they use Water and anti-freeze. (Maybe a few other things)


thanks everyone for their help!

Luis

 

[ko99]

Luis,

Correct, heat pipes do not cool below the ambient. They act similar to a conductor, except they have losses at each end and are effectively isothermal in between.

Most liquid systems don't cool below the ambient either. Perhaps you could provide details. Is it an emersion system? Are you also using TECs?

ko

 

[musicians4um]

hmm....

well my whole idea is to design a cooling system for computer processors that out performs what is currently on the market, yet can still be made in a way that it will be affordable not only for me, but for customers as well.

i am open to other ideas,

the reason i say liquid cool, is mainly because that is what is hot on the market right now.

some people use peltiers to help the cooling process, but they produce condensation. Refridgeration is another possibility, but i am also trying to stay away from that because it also produces condensation, and the general public doesnt know HOW to waterproof their computers.


any other ideas?

 

[ko99]

I have lots of ideas on cooling processors (it's kinda what i do for a living). There are also many creative solutions already out there. Try coolingzone.com, electronics-cooling.com, Aavid, Thermacore, ChipCoolers, Thermaltake, Dynatron, Melcor, many others.

There are so many different cpu versions, enclosures, and markets, that there is no single "best" solution. You may want to focus on a particular niche of the market.

Good luck

ko

 

[TNT2bluz]

Actually you can't just watercool a CPU below ambient as there is no means for your coolant to assume below ambient temps unless you add a thermoelectric couple or a refrigeration unit to the loop.

Some waterblocks are made of silver, but this is not a very commercially viable option for the mass market for obvious reason. Hence copper is the metal of choice.

 

[chicopee]

THE MATERIAL W/ THE HIGHEST THERMAL CONDUCTIVITY AT THE TEMPERATURE OF INTEREST SHOULD BE INVESTIGATED FIRST.