Synthetic diamonds transfer heat better than metals.

Some questions:

  1. How much percentage are synthetic diamonds better at transferring heat than metals like copper and other metals in todays cooling devices for computerchips ? A rough percentage estimate is good enough for me.

  1. Does it make sense to use synthetic diamonds for cpu coolers or is there another limiting factor, like maybe the ammount of heat that can be transfered to the air ?

Bye, Skybuck.

Reply to
Skybuck Flying
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Synthetic diamond generally around 250% better than copper, pure diamond around 500% better

In an ideal world it would be the best solution, however I would swop my diamond heatsink for a fanned copper heatpipe plus a brace of 8800GTX's any day!!!

Lorne

Reply to
Lorne Mower

I have no numbers, but i understand that diamond is a better thermal conductor than copper. Actuall, if there is a lot of heat to transfer, it makes sense (and this has been done) to mount the IC directly on a diamond chip, which then is mounted on a large heatsink. And you are right; moving thermal energy from the heatsink to cooler air can be a problem. Basically, you do not want lamanar flow at the heatsink surface, as that boundary can become (relatively) insulating. Once the transfer is made, lamanar flow is desirable to get that heat away as efficently as possible. Can become a nasty tradeoff...

Reply to
Robert Baer

| > 1. How much percentage are synthetic diamonds better at transferring heat | > than metals like copper and other metals in todays cooling devices for | > computerchips ? A rough percentage estimate is good enough for me. | >

| > 2. Does it make sense to use synthetic diamonds for cpu coolers or is there | > another limiting factor, like maybe the ammount of heat that can be | > transfered to the air ? | >

| > Bye, | > Skybuck. | >

| >

| >

| >

| >

| I have no numbers, but i understand that diamond is a better thermal | conductor than copper. | Actuall, if there is a lot of heat to transfer, it makes sense (and | this has been done) to mount the IC directly on a diamond chip, which | then is mounted on a large heatsink. | And you are right; moving thermal energy from the heatsink to cooler | air can be a problem. | Basically, you do not want lamanar flow at the heatsink surface, as | that boundary can become (relatively) insulating. | Once the transfer is made, lamanar flow is desirable to get that heat | away as efficently as possible. | Can become a nasty tradeoff...

Someday we will be able to make large diamonds cheaply. Then we will make solid diamond heat sinks with internal water channels and dissipate 10 kw in a few cubic centimeters. Pentium 4's will come back in stile and run at 10GHz!

Mike Sicilian

Reply to
mike

Won't work. To suck up 10KW from few cc the water would have to flow so fast that it would likely heat up the heatsink. Of course I didn't do the math :)

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    Boris Mohar
Reply to
Boris Mohar

Pure diamond is roughly twice as good a heat conductor as pure copper. Isotopically pure diamond is several times better again.

The problem with diamond is that it's not available in big chunks. A thin film of diamond doesn't spread heat laterally, so interposing it between a chip and a heat sink makes the thermal situation worse, not better. Diamond would only be useful if you could make the whole heatsink out of it, or mount the chip on a big and *thick* hunk of diamond embedded in a copper heatsink. I could tell you more except for that damned NDA.

There are diamond-filled greases and epoxies. Their thermal resistance isn't much better than other types, since the thermal resistance is dominated by the grease or epoxy between the fill grains. In that the diamond fill is usually big grains, the diamond stuff may well be worse.

Nowadays, probably the best heatsink is a water-cooled copper block.

John

Reply to
John Larkin

How about taking a page from the nuclear power industry? A pressurized boiling water reactor should have some impressive power density numbers. We should be able to do the same thing, and use the steam for cooking, showers, laundry, steam cleaning carpets, etc.

Unfortunately google doesn't want to give up any pages that talk about watts/cm^3 right now:)

Regards,

Mike Monett

Antiviral, Antibacterial Silver Solution:

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Reply to
Mike Monett

Some questions:

  1. How much percentage are synthetic diamonds better at transferring heat than metals like copper and other metals in todays cooling devices for computerchips ? A rough percentage estimate is good enough for me.

  1. Does it make sense to use synthetic diamonds for cpu coolers or is there another limiting factor, like maybe the ammount of heat that can be transfered to the air ?

Bye, Skybuck.

------------------ Reminds me of an email I got long ago..and it's still on my computer and I've pasted below...

. [Received Email] Hi D

The atoms of any crystal are in a state of vibration, their average kinetic energy being measured by the absolute temperature of the crystal. In certain phenomena it becomes evident that this energy is divided into discrete bundles; the energy bundles behave like particles in some respects and are termed phonons.

With diamond particles in a thermal adhesive, when these phonons reach the outer edge of a diamond particle it seems they tend to be reflected back into the particle rather than conveying the energy (heat) to the resin or an adjacent diamond particle.

We are working on solutions to this phenomenon, but simply adding diamond powder to an existing thermal adhesive or making a thermal adhesive with pure diamond filler is not nearly as effective nor as simple as it would seem to be.

This being said, our OEM customers consistently tell use that our adhesives are the best performing ones available. You may be interested in our Medium Cure Ceramic Epoxy and our Slow Cure Ceramic Epoxy. The Slow Cure Ceramic Epoxy performs on par with out silver adhesives.

[My Email I sent] Hello

I know that diamond is an excellent heat conductor and I'm curious as to why Artic Silver does not have an "ultimate thermally conductive" adhesive? I realize price might be higher but some people don't mind.

Reply to
D from BC

Well let's see.

10kw = 34,130 BTU/hr

That works out to a Flow-temp rise constant of about 68, in gals/min and degrees F.

In other words, 1 gpm will move 34,000 btu.hr at a temperature rise of

68 degrees F, 2gpm will do it at a 34 degree rise, etc.

I'll let someone else put a number on the surface area of heat exchanger required.

Reply to
BFoelsch

Perhaps the use of a low boiling point liquid that has been previously cooled to almost freezing may do; laminar flow on the heatsink surfaces will be a severe impediment.

Reply to
Robert Baer

Better yet, a water-cooled block of silver.

Reply to
Robert Baer

allowing for a 20K rise in the temperature of the coolant that'd require about 2.48l per second

possibly a 1 or 2 KW pump would be enough :)

--
Bye.
   Jasen
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Reply to
jasen

Pyrolytic graphite looks good too, 1900 W/mC at 30C, vs 386 for pure copper at 20C, according to page 338 of the 1998 Schaum's Outline on Heat Transfer, but manufacturers only spec 300 or so. I wonder why.

Nick

Reply to
nicksanspam

In article , John Larkin writes: |> |> The problem with diamond is that it's not available in big chunks. A |> thin film of diamond doesn't spread heat laterally, so interposing it |> between a chip and a heat sink makes the thermal situation worse, not |> better. Diamond would only be useful if you could make the whole |> heatsink out of it, or mount the chip on a big and *thick* hunk of |> diamond embedded in a copper heatsink. I could tell you more except |> for that damned NDA.

Standing for Not Deliverable, Actually? :-)

Regards, Nick Maclaren.

Reply to
Nick Maclaren

In article , "mike" writes: |> |> Someday we will be able to make large diamonds cheaply. Then we will |> make solid diamond heat sinks with internal water channels and |> dissipate 10 kw in a few cubic centimeters. Pentium 4's will come |> back in stile and run at 10GHz!

Illiad has said it all:

formatting link

Regards, Nick Maclaren.

Reply to
Nick Maclaren

It all depends on how fast you need to push the IC's and your weight constraints. Right now the best bet might be to run a plain old freon refrigerant past the back of the CPU chip-- plain old mechanical compressor and all-- IF you have the space and can tolerate the power and weight. Much cheaper than using diamonds and you can get much lower chip temperature and therefore more speed.

Reply to
Ancient_Hacker

Not even cost effective, but probably the best that can be done in an ordinary office or household setting. In an industrial setting using LN2 in a copper plate wins easily.

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 JosephKK
 Gegen dummheit kampfen die Gotter Selbst, vergebens.  
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Reply to
joseph2k

BFoelsch a écrit :

Arghhh...

Arrrgggghhhhhh...

AAAArrrgggghhhhhh...

Not me, you just killed me...

--
Thanks,
Fred.
Reply to
Fred Bartoli

"Fred Bartoli" wrote in message news:45965297$0$290$ snipped-for-privacy@news.free.fr...

My thoughts entirely. No wonder NASA crashed a space vehicle on Mars due to unit conversions !!!

Lorne

Reply to
Lorne Mower

Synthetic diamonds can be made at any level of "purity" desired.

What do you mean by "pure diamond"?

Where do you get your figures for your thermal conductivity comparisons?

Reply to
Richard Henry

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