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Carbon Nanotubes May Make The Ultimate Heat Sink
SEWilco writes: "Looking for something to make a really good heatsink? This EurekAlert summary points out that U of Penn researchers have discovered that carbon nanotubes carry heat quickly, and unexpectedly bundles of them also do this. It's due to how the heat is carried, not due to the tremendous surface area." Interestingly, according this summary, "[h]eat energy in nanotubes is carried by sound waves; in materials that are optimal conductors of heat, these waves move very rapidly in
an essentially one-dimensional direction. Drs. Fischer and Johnson found that sound waves bearing thermal energy travel straight down
individual carbon nanotubes at roughly 10,000 meters per second, behavior consistent with superior thermal conductivity." But what would all the overclocking sites do if the ultimate heatsink was shapeless and grey?!
Fuzzy heatsinks. Lots of nanotubes, splaying out a bit to transfer the heat to the air. Like a layer of velvet.
"I can only show you Linux... you're the one who has to read the man pages."
WHAT are you planning to do with the heat? Heat sinks don't destroy heat, they move it. (Actually, NOTHING destroys heat. Part of that conservation of energy thing.) For the big heat sink that sits on my Athlon, they move the heat from the surface of the chip to the air in the heat sink. Little fan on top moves air out of the heat sink and into the rest of the case, where (hopefully) the other fans blow it into the room, allowing new colder air to be sucked in. But the heat's still going somewhere.
From reading the article, you're (sorta) right that you could use these to in essence suck the heat out of a component, but you'd still need a heat sink to help disipate the heat. Look at the back of a fridge if you can - if you can find an airconditioner you can see into, try that instead. Look for the tubing wrapping around - that's basically a heat sink. Refridgeration works by compressing air so that the heat in it becomes "denser" if you will, making it hotter. Heat is then disipated elsewhere, and then the air is decompressed, and it's cooler than it was before (heat was lost).
Although the article suggests they could be used to cool parts otherwise too hot, it leaves out the part explaining what they end up doing with the heat. (They probably conduct it somewhere else and let it disipate there.)
You'd still need something to disipate the heat - they don't destroy heat. They're almost like fiber optics - they move energy down the fiber. Heat sinks help disipate heat - this could make them more efficient in doing so.
You are in a maze of twisty little relative jumps, all alike.
I may be talking out of my ass here but if the thermal energy applied at one end of a nanotube propigates down the tube like a sound wave, would it be hypotheticly possibal to use the equivilent of active noise cancelation to ``eat up'' the heat?
I doubt this would be feasable because you'd need to actively cancle each tube seperately but in theory...?
--Ben
I think you've rubbed them the wrong way - they are modding you up. In the same way, I've hit the 50 cap, so I feel like burnin' up some karma just so I can see it go up again. Took a summer o' karma whoring to get it there, and then he locks it at 50. The bastard.
You are in a maze of twisty little relative jumps, all alike.
Except for "Is it in yet?"
-Pete
It also reminds me of a best-of-usenet post I saw once, where somebody thought a little bit about the scene from _Fellowship_of_the_Ring_ where they throw the One Ring into the fireplace and it's still cool to the touch when they pull it out. They theorized that the *real* reason that Sauron wanted the One Ring back was to use it as a heatsink for the main MordorNet CPU...
If you want to get rid of the bathwater, you've got to throw out a few babies.
When I first saw the post, the first thing that popped into my mind was nanotube inlays, ala copper inlays in Alpha heatsinks. You run a group of nanotubes from the center of the contact patch to the end of each fin. This pulls the heat away from the actual heat source and creates a greater temperature delta across the fins. The greater the DT, the more efficient the heatsink (lower thermal resistance). IME, it's tough to get the chip below (ambient + 10 C), but with nanotubes to pull the heat to the fins more efficiently, you may be able to get (ambient + 5 C) or less. I doubt you're going to see any nanotubes carrying heat distances larger than an inch. But I think just dumping the low grade tubes into the molten mold could lower thermal resistance the same way copper inlays do.
-Vic If you can't figure out my email, then don't.
Wow, that brings back memories of my thought experiments when I heard about electralizing H2O into H2/O2. I figured the way to make a car was to put water into the gas tank, explode it in the cumbustion chamber and end up with H2O again that you could pump back into the system and start all over again.
:)
:).
My poor gr 6 teacher got the unenviable job of explaining the laws of thermal dynamics to me
I buy your prediction. The three laws have proved to be remarkably resiliant thus far
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On the whole, I find that I prefer Slashdot posts to twitter ones because I don't get limited to 140 chars before
Luckily, we don't have to worry about that anytime soon. The nanotubes might move heat away from the CPU faster, but they still have to move that heat to somewhere, which is where all the fins and pins and fans come into play. Those have nothing to do with moving the heat from the CPU to the heat sink, and everything to do with moving the heat from the heat sink to the surrounding air, thus allowing more heat to move from the CPU to the heat sink, etc.
On the other hand, if they could build a heat sink with single carbon nanotube-thick pins spaced right, and a good fan...
wanna market this thing on a TV infomercial? we can do it alongside George Forman's chicken rotisserie.
make world, not war
Couldn't the carbon nanotubules be integrated into the CPU itself? And for that matter many other heat prone computer components. This would provide far superior heat disipation, as it would go from source to void.
Spring is here. Don't believe me, look outside!
Room-temperature superconductors and a nice big lake. I'll bet I could overclock that Athelon somethin' awful...
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Every year during my review, I just pray the words "slashdot.org" aren't mentioned.
Just recently read something about isotopically pure C-12 diamond being the best conductor:
/glimpse.txt/physnews.131.2.html
http://newton.ex.ac.uk/aip
reports that refined C-12 carbon diamond has a thermal conductivity coefficient of "410 W/cm-K, in 99.9%-pure C-12 at 104 K". They estimate 99.999% pure C12 diamond could be as high as 2000W/cm-K.
Whats the value for CNTs? I dont see one in the article... did we give up on pure diamond films
already? A.C.Clarke would be sad!
Math.
I could also see this being used for car engines, air conditioning unit ... etc what ever you can think that needs to cooled down. I could see this being the next "NEW COOL" technology. Soon you will see carbon nanotube item being sold by infomercals.
now if only the chips were cool so that we wouldn't even need a heatsink in the first place
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If they're so great, when are we going to start seeing stuff made out of it? I'm still waiting for my first carbon-nanotubule-fiber-based pair of underwear. Mine tend to get holes quickly.
What this stuff should be used in is not making the sinks, but the thermal paste you stick between the sink and the chip to improve the heat transfer between the materials. Current pastes have been frowned upon because they're not as efficient as bare metal. So overclockers have been relying on planing, luck, and only a tiny dab of goo when absolutely necessary. (As witnessed by the recent "Athlon-killing-heatsinks" problem.)
Now we've got a material that's a better heatsink than bare metal. But that doesn't mean we suddenly drop all our metal stock and go 100% nanotube. Notice down at the end of the article where they talk about the weak bonding of the tubes. They point at that this actually improves the heat transfer ability, but it also makes them brittle. So yeah, you could probably build a nice hefty sink entirely out of nanotubes. But one wayward knock from a hard drive and half of it ends up scattered about your mainboard.
Using it for paste is much more practical. No matter how flat you make the surfaces, bare metal can never make better contact than if you sandwich some paste in there.
Another potential use is for low-temperature experiments (the micro-kelvin kind, y'know). Since it seems that even a single nanotube can act as a sink you could nestle one right up to whatever you're trying to chill and just suck the heat out of it.
Any sufficiently advanced civilization is indistinguishable from Gods.
Lateral heat spreading is a problem. But that's why you use copper heatslugs and/or thicker baseplates. Notice that the copper slug from the P5mmx and Celeron is back on the P4. No more die back.
There's a second problem that creates the central hotspot: uneven airflow from the usual co-axial fans. There's a dead-spot underneath the fan hub, and most of the airflow is into the periphery of the heatsink and out the extruded ends. Fortunately, the geometric area in the center is fairly low.
I might be tempted to blind one end of the heasink off with tape to force more crossflow. But I don't know if the improved flow pattern would make up for the reduced flowrate.
The problem with most heatsinks today is that the "hotspot" in the center of the chip, and thus the center of the heat-sink. Basically, the heat tends to concentrate in the center, and cools off the farther it is from the heat source. You end up with a thermal gradient over a large heat sink. (Remember college physics and doing equilibria problems? Ugh.) At some point, the outlying parts of the heatsink contributes little to the overall cooling of the core. If the nanotubes make good thermal "superconductor", it makes it possible to make larger heat sinks with better heat distribution and dissipation. That would be A Good Thing. Now, if they can only make cooler units that run silently!
Maybe a more effective temporary heat sink -- like a small black hole.
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Every year during my review, I just pray the words "slashdot.org" aren't mentioned.
It's cool to see my old college prof and his research get mentioned here on /. Too bad he taught us the senior physics lab class, instead of thermodynamics. Otherwise we coulda been way ahead of the competition in overclocking ;-)
make world, not war
Hmm...
Forget about overclocking the Pentium IV... you know what we could do with this kind of technology and the proper funding?
Battlemechs! Marauders that won't overheat in the middle of a fight! Jenners with dual PPCs!
Tongue-tied and twisted, just an earth-bound misfit, I
Learning to fly, Pink Floyd.
these waves move very rapidly in an essentially one-dimensional direction
Wow, I wonder how that works, moving in one dimension.
To me that's as likely as me being drunk moving in one direction. It just ain't happening.
I always thought that a position would require at least three dimensions, and since movement implies time, would require at least four...
Breace
I've got tons of karma and thanks to the cap at 50, it can only go down. I've got nothing to lose. Every time you take one of my posts under 2 on this thread, I'll post a new one at 2. I can do this for the next 3 days. /. I love hearing from John Crmack on the subject of Doom III. I love specious reasoning and IANAL posts on the DeCSS threads. I love moderation as a concept.
/. discussions. Moderating based on the posters opinion of Linux or your opinion of the poster is an abuse of this trust.
/. community (which is how you get the +1 bonus after all) I feel a responsibility to attack abuses of moderation whenever I see them.
I've got a problem with the way moderation gets done around here.
You see, I love
What I can't stand is vindictive or thoughtless moderation.
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When you moderate, you've got tons of options. If you think a post should have a lower score than it does, there's 'redundant', 'offtopic', 'troll', 'flamebait' and 'overrated'. They all have the same effect of reducing the post score by 1, but they also have a side effect of providing feedback to the poster. If a post is stupid, but refers directly to the topic of the article, it is completely on-topic. Moderating it as 'offtopic' is worse than posting a followup of "IF I EVER MEET YOU I WILL KICK YOUR ASS"
As a moderator, you've been entrusted with maintaining the quality of
You have an obligation to moderate thoughtfully. If you aren't willing to spend serious time thinking about whether or not your moderation is appropriate, you should mark yourself as 'unwilling to moderate'.
I don't like polluting this thread with complaints about moderation, but it seems to be the only way to drum this into your sheeplike skulls.
For those of you who moderate fairly or don't moderate at all, I apologize, but as a contributing member of the
--Shoeboy
Look past your own vendettas for once.
Yeah yeah, I know, (Score: -1, Offtopic). Fuck off.
______
Love Always,
Cobalt
This may sound out of fashion but a one-way heat transfer system made from carbon would be a very important component in making nuclear reactors that are considerably safer and efficient than current ones. Heat transfer has always been the weak saftey link in nuclear power. Radioactive carbon does not emit dangerous radiation. Combine this with liquid lithium as the primary insulation medium and you have a reactor that is safer than most coal plants, produces electricty at lower prices and does not become long-term radioactive. Of course, Al Gore has pulled the plug on such research.
So long and thanks for all the fish . . . !!!
It so happens that Slashdot has two articles on carbon nanotubules today...one on their heat conducting properties, the other on its potential use as a rigging cable for a space elevator.
:-)
The space elevator article said that the carbon nanotubules may have a strength as high as 200 giga pascals. However, this article says
"Ironically, the same weak linkages that make carbon nanotubes superior for heat conductance could deflate scientists' earlier expectation that bun-dles of them would provide unrivaled mechanical strength."
Umm...I think that the scientists from the second article better call the scientists in the first article.
Did anyone else notice this?