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Carbon Nanotubes May Make The Ultimate Heat Sink 110

Posted by timothy from the please-put-that-with-the-LED-backlights-ok? dept.
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?!
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Carbon Nanotubes May Make The Ultimate Heat Sink More

Carbon Nanotubes May Make The Ultimate Heat Sink

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  • Fuzzy heatsinks. Lots of nanotubes, splaying out a bit to transfer the heat to the air. Like a layer of velvet.
  • You Can't eat none well done humans with Out risking your health, I mean look at these dirty little animals. Soon though human farming will allow us (You now who we are) to eat none well done human.

    -- I find it so cute when two humans come out of the steamer or deep fryer holding hands.I have to eat them both at the same time.
  • Do you suppose the heat radiated by the tubes is polarized? Vertically? How are they as an insulator from the side. Does this shit even matter? I mean, from mystery we come and to mystery we return. Turn out and investigate the wide wierdness or turn in and masticate my mindchunks into more and more elaborate patties. Will this stave off my appointment with the worms one second? Can I get more chicks with a carbon nanotube penissheath? A we all just fucking dog slaves? Click on clickers. J
  • Couldn't it be that the 40W of heat is transmuted to 40W of soundwaves? Maybe a bit loud bit still pretty cool. :)

    -Danny
  • Does anyone remember a concept from science fiction called Maxwell's Demon? The way it was supposed to work was to have a membrane between two chambers that would actively select warm molecules from one chamber and put them in the other, while grabbing cold molecules from the other chamber and putting them in the first one.
    In essence, a membrane that would passively perform as an incredibly efficient heat pump.
    The idea stuck pretty well in my head throughout high school; but when I got to college, Lo! And behold! My physics professors told me such a system could not exist, for the existence of such a passive system would violate the laws of thermodynamics. The very existence of Maxwell's Demon would allow for a perpetual motion machine (which, in all naive curiosity, I attempted to build in sixth grade. LOL). Even a Peltier junction requires energy (electricity) to work, and even that is not a truly effective heat pump: some of that energy is lost as heat, and contributes to the overall heat of the enclosed system. This is noticed if you suddenly cut the power to a Peltier junction - you will find that the entire loop is considerably warmer than room temperature.
    So, here's my prediction: the carbon nanotube heat pump works great... in small quantities. If you try to engineer a membrane of these things in quantities humans can physically observe, we may find that individual tubes have their own resonant frequencies (remember, heat is being carried as sound energy one-way down the tube) which are close enough together so as to interfere with each other. Heat no longer flows one-way and resumes the entropic behavior we all know and love.

    Remember, Kiddies, you heard it here first.

    Solomon Kevin Chang
    Futurestep.com
    A division of Korn Kerry International
  • "Time isent a dimension ...."

    Depends what you define as dimension and as your viewpoint/perspective. Just like you disregarded all other dimensions but one, since the heat only moved in one direction, you can also select how to view the world in infinite ways. Including adding one dimension for time. You may even add it to the beginning of the list ;-P

    - Steeltoe
  • at what cost though? and how will it perform vs silver based paste? you can get 77% silver based paste for $14/5.6oz... and it works great www.arcticsilver.com
  • I haven't left the case on my computer in years.
    Maybe I'll drag it out of storage and place it next to my computer to be used as a heat sink? :-)
  • Hasn't anybody here heard of peltier coolers? They use electric power to suck the heat from one side of their surface and transfer it to the other. The temperature difference from one side to the other can be as much as 120 degrees or more. The only problem is that since they do run on electricity, they do generate a tiny amount of heat themselves. Meaning your fan had better be running, or else the insides of your case are going to go into meltdown (okay, that might be an exageration, but if your fan fails, you'll definitly be toast). Most people put one in between the CPU and the heatsink. However, I was wondering why more heatsink companyies don't integrate them into their designs? You could have one mounted to contact the CPU, and four others pointed sideways inside the heatsink itself to transfer this heat radially away from the "hot point" of the CPU. This would not only remove heat from the CPU more efficiently, but would also distibute the heat through the heatsink better.
  • I may be way off here, but being tightly-packed carbon...

    Would nanotubes be electrically conductive or not?
  • There's nothing wrong with them. They're quite as a mouse, I don't even know they're in my computer. It's the goddamned fans that have to go. Make the best heat sink possible using nanotubes, and make it good enough that you don't need a fan - and then I will be happy to buy it.

    "I can only show you Linux... you're the one who has to read the man pages."

  • Would you REALLY want 40W of soundwaves inside your PC's case? Even if the hard drives were unharmed, wouldn't extra noise encourage the chips/cards to "creep" out of their sockets/slots?

    (Ok, so it's a long shot, but hey, it's something to give thought to...)
  • Sorry, I've gotta nitpick that one for two reasons. "Mote" was by both Jerry Pournelle and Larry Niven, and Niven used the heat superconductor in quite a few other stories. (Recall "Ringworld", and the solution to flying over a field of sunflowers. For those who haven't read it, the sunflowers in Niven's "Known Space" series are reflective, and will move to focus the local sun's rays on anything flying over the field. The solution involved a heat superconductor floating where the flowers could shine on it, and trailing down to a nearby lake.)

    But yes, Niven's superconductor of heat is the first thing I thought of when I read that.

    No, no, no. It ain't ME babe,
    It ain't ME you're looking for.
  • Hm... at that price, I wonder if anyone would sell just 1 or 2 grams... It'd be fun, if nothing else to try making your own diamond thermal paste...

    (Although I'd not be surprised if for some reason it turned out to be an insulator.)
  • Carbon nanotubes are tubes, so they can be thought of as having only two directions; flowing down the tube, or flowing up the tube. If you think about it this way, then yes, they're right in saying that it's essentially a one-dimensional direction.

    You're right, though; a group of them would require modelling in at least three directions.

    Cheers,

    James
  • Anyone know how it would compare with diamond?

    If I recall correctly, diamonds are not so good at conducting heat. After they reach some temperature, they burn up.

  • Re:hold on, why have a heatsink at all! (Score:5)

    by _xeno_ ( 155264 ) on Thursday September 07, 2000 @08:02PM (#795805) Homepage Journal
    This would provide far superior heat disipation, as it would go from source to void.

    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.

  • Aren't Carbon Nanotubules hard to make? (Score:1)

    by Anonymous Coward
    Last time I checked, which admittedly was half a year to a year ago carbon nanotubules were notoriously difficult to make with the best methods being an arc of electricity at high voltages passed over a source of purified carbon. In regards to production this creates micrograms of nanotubules I believe which would seriously put a damper on any cooling efforts due to sheer expense. Also, in regards to placing these inside the cpu core to transfer heat out. The difficulty of placing a carbon tubule which probably just as large or larger than the etched circuitry inside a cpu core without damaging the core would require finer technology than available today. Technology that would probably render the use of various lithography techniques used in cpu creation obsolete. The best use I can see for carbon nanotubules would prolly be in some form of thermal grease or thermal compound. Although due to their unidirectional nature in which heat is transfered in one direction apparently only half the tubules would conduct heat away from the core due to the nature of random assortment and positioning, if they really do conduct heat as well as predicted that would be impressive. Unfortunately I can't see even an improved thermal grease giving more than a few degrees improvement over the best compounds available today.
  • There is nothing in the summary to indicate the magnitude of the conductivity. But since diamonds are about 10 times as conductive as silver, I would expect the results of this 'breakthrough' to be at least an order of magnitude larger than that.
  • 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.)

    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.
  • before someone else patents the almost-obvious ..
  • WHAT are you planning to do with the heat?

    Touch the metal on your computer case.

    Good...

    Kinda cool to the touch, yes?
  • Actually, NOTHING destroys heat.

    Except for "Is it in yet?"

    -Pete

  • Oh come now, for one-way thermal superconductivity, the answer is obvious (at least to any coder)...

    Processor at one end, your cup of coffee at the other.

    Skevin
  • I think that Oxygen and nanotubes don't mix very well, and I'm not sure if the "nanotube paste" would age very well..

  • The last machine I saw with dual PPCs [be.com] had no problems with overheating...
  • Neat! I have always wanted to know how a fridge works.

    Tune in again next week, when we discover that a toilet works by siphoning.

    -Pete

  • what could you do to dissipate or change the heat energy into a different form of energy? perhaps something that you could store and use against them in YOUR laser? :)

    eudas
  • > Processor at one end, your cup of coffee at the other

    Oh yeah, and don't forget to replace content and consume it every 5 minutes. Failing to do that might result in combustion of both ends.
  • But what would all the overclocking sites do if the ultimate heatsink was shapeless and grey?!
    Heh... they haven't seen the stuff that comes out of the tube of Radio Shaq heat sink compound I bought the other day, have they? Shapeless, gray, and very nasty. Takes industrial strength cleaner to get it off anything it comes in contact with. Solved problems I've had with a coupla AMD K6/2 and K6/3 processors that were running hot.
  • I'm sure its been said, buut hhis will take Overclocking to new heights!!!!!!

    I found a webpage one time were a guy actually fried an egg over a p120 heatsink by dumping the egg right into the heatsink, sorry I lost the page, I just reformatted my harddrive :-(
  • 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...
  • 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.
  • 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 :).

    ----
    Remove the rocks from my head to send email

  • It's the heat superconductor from "The Mote in God's Eye" by Jerry Pournelle.

    What you really want to do with these is coat your spaceship with them so you can dump all the heat from the laser your being attacked with into a block of ice in the middle of your ship. :-)

  • A tiny ammount of heat? I hope you're joking!

    Peltiers are incredibly inefficient. They produce more power than they pump. And most are 60-70 C DT with zero load, which of course never happens.

    I did a bit of experimenting and heres what I came up with. A single "55 watt" peltier element on a 25 watt load ends up outputting well over 100 watts (25 pumped + about 90 produced itself, 12V * 6A or so) which leads to about 14 deg C DT from hot side to cold side. Crunch a few numbers and you'll quickly find you either need a water to radiator intercooler or an incredible heatsink to gain anything over a normal heatsink. If a normal heatsink gives you ambient + 10C, you need to have a heatsink that can get rid of 115 watts and stay under ambient + 24 or you gain nothing. With my water intercooler, the hotside waterblock stayed at about ambient + 8, so my dummy load was only 6 under ambient, or 16 under what a normal large OEM heatsink would do. Seriously minimal gains for the ammount of work and the price.

    Plus peltiers can cause condensation and a peltier failure is catastrophic.

  • What you really want to do with these is coat your spaceship with them so you can dump all the heat from the laser your being attacked with into a block of ice in the middle of your ship. :-)

    that's all well and good until you melt, then vaporize, the ice cube such that the steam pressure blows a hole through the ship hull (after cooking the ship's passengers, of course). :-)

  • Why not design home heating using ths? It would minimize the heat lost out of the pipes without insulation, therefore thinning pipes.

    Anything that is generating heat could have an outlet that would push the heat into the heating system, thus relaiming some of the energy lost.

    Cars could have nanotubes that suck the heat of a car back to an array of nanogenerators, which would do away with the current coolant system and generation system.

    Being able to channel heat at this level opens new uses for it as well. The RAM in a graphics chip could be a heat circut, instead of electric, so that it actually USES the heat generated, instead of wasting into the open air.

  • Shapeless Heatsink (Score:3)

    by Jade E. ( 100300 ) on Thursday September 07, 2000 @07:45PM (#795828) Homepage
    But what would all the overclocking sites do if the ultimate heatsink was shapeless and grey?!

    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...


  • It seems you can buy a samples of carbon nanotubes from Rice. (Google cached mirror) [google.com]
    So who is going to be first to stick this on a computer. Be the first on your block with a nanotube cooled processor. I'm sure a Pentium IV could really use one. Not sure how your going to mount fans on a bunch of single-wall nanotubes... but someone who really wants to cool their comp will work it out
  • way back I remember reading articles and being intrigued by the possiblity of phonon (sound waves) assisted electron tunneling "in vivo" in cytochrome enzymes. Is the initial part of carbon nonotube heat transfer phonon assisted?
  • Yeah, that's a totally great idea. Use the superconducting shell to evenly distribute the heat of the laser, thus ensuring humans are evenly cooked. I hate it when some humans are burnt, and others cold and raw. blech.

    wanna market this thing on a TV infomercial? we can do it alongside George Forman's chicken rotisserie.

  • Well for starters we would pack our cases with tha shapless grey goo, then but great big heatsinks on the sides of the cases. Yeah, and then strap 100cfm fans to every inch of the heatsinks. OH and maybe throw a peltzer in there for good measure. Or we could route the water pump from a Chevy Nova through a cooling blanket that covers the whole case. Yeah thats it. 300 horse power for my ultimate kickass cooling rig ;]
  • mmmm... heatsink goodness :)
  • 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.

  • Larry Niven's heat sink is better. (Score:3)

    by Skyshadow ( 508 ) on Thursday September 07, 2000 @07:47PM (#795835) Homepage
    I'd rather have the heat sink that one of Larry Niven's characters rig in Ringworld Engineers (I think; either that or Ringworld Throne).

    Room-temperature superconductors and a nice big lake. I'll bet I could overclock that Athelon somethin' awful...

    ----

  • Just recently read something about isotopically pure C-12 diamond being the best conductor:

    http://newton.ex.ac.uk/aip /glimpse.txt/physnews.131.2.html [ex.ac.uk]

    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.

  • Re:Shapeless Heatsink (Score:3)

    by Kierthos ( 225954 ) on Thursday September 07, 2000 @08:07PM (#795838) Homepage
    Possible, but given the size of the heat sinks in the computers I've taken a look at lately (admittedly, these are some older computers with big heat sinks), they could decrease the actual volume of the heat sinks and still redirect enough heat efficiently enough.

    Also, you could use the carbon nanotubes to "move" the heat to heat sinks in the base of the computer (as an example) away from all the vital components. Imagine a sheath around the processor converging into a "wire" of nanotubes that leads to the heat sinks. It may make it more difficult to modify the processor, as you would have to be careful about damaging the sheath, but it may be worth it.

    Of course, I could just be blowing smoke.... obviously there's going to have to be a lot of configuration testing done.

    Kierthos
  • I almost posted a reply just like yours, but then I realized that this guy could be right, although not for the reasons he was thinking of. A heat sink, for all intents and purposes, is just an extension of the surface area of the chip due to the fact that air is a really bad heat conductor and requires lots of surface area to transfer lots of heat. But, if the material the chip is encased in was a good enough heat conductor, you could make due with much less heatsink to achieve the same effect, provided you had sufficient airflow. While I don't think this material will make it, we could theoretically find something that would dissipate heat so well that a heat sink would be unnecessary, since the airflow over just the surface of the chip could be sufficient to cool it. Of course, you're also talking a really strong fan, but it still might be done. Eventually.
  • I have a wonderful pair of trousers made from carbon nanotubes which were developed here at the Institute of Advanced Trouserology in Wellington, In summer they draw all the heat away keeping me New Zealand. cool and fresh. "Aha, but what about winter time, Mr SmartyPants!" I hear you say. Well, I simply turn them inside out and keep myself toasty warm... They do itch a bit though...
  • now if only the chips were cool so that we wouldn't even need a heatsink in the first place
  • Neat! I have always wanted to know how a fridge works. This site rocks!
  • The arc discharge method currently can produce about 1g per day. There is a newer production method developed at Rice University that uses a pulsed laser to vaporize a graphite target doped with metal particles. This process can produce 10g per day. For more information on this process, check out Dr. Smalley's publication list at: http://cnst.rice.edu/respubs.html Article #249, #252
  • I am writing my Master's thesis on the strength properties of single-wall carbon nanotubes, so I know a little about what's going on. So far, both theoretical and experiment work confirms a yield strength of over 200 GPa which is about 100 times stronger than steel. SWNTs also have been shown to have a strain-to-failure of over 5% and that's just a confirmed lower bound. The biggest challenge facing NTs in materials research is that they are very small and there is no known way to catalyze continued growth or grow individual tubes of high purity longer than 1 micron in length. The inter-tube van der Waal forces are the limiting factor in current nanotube rope strength characteristics, and gives a yield strength around 40 GPa.
  • I was thinking about that, too... Instead of dissipating the heat directly with a heatsink made out of nanotubes, just use them to conduct the heat elsewhere. I don't know about big case heat sink, I was thinking more along the lines of conducting the heat either: a) outside or b) into a heatsink submerged in water, or some cooler substance. Either way could (depending on what climate you live in/what substance you used) potentially provide much better heat dissipation than any room-temperature arrangement...
  • Problem with these things is that they wouldn't work as a heatsink at all - they conduct heat. Putting them in the chip would allow you to conduct heat away from the chip - which would be a good thing, probably. But you still have to get rid of the chip. From what I understand, these things are no good at radiating heat, only conducting it. The heat sink is a method of radiating heat better than the flat surface of the CPU would do. You'd still need something like a heat sink - somewhere. It's what "gets rid" of the heat. I'm not sure exactly how these things work at the ends, but I think they're like wires for heat - they conduct the heat from an end to the other end. But since I'm not a thermaldynamiction (that a word?), I'm not sure. I'd have check up on my thermodynamics and learn some more to be sure what would happen. These things are good at moving heat, but I'm not sure how it works at the ends.

    But, if the material the chip is encased in was a good enough heat conductor, you could make due with much less heatsink

    Oh come on, you have the same amount of heat! You'd need the same sized heat sink - it's still AIR this is being radiated into! Actually, I'm not sure how well these things would radiate heat at the ends anyway.

  • Okay, I'll bite; how was my comment redundant?

    I'd appreciate it if I didn't get moderated down for absolutely no reason, okay? If you do moderate either of these posts down, logout, and state your reason anonymously; I don't care about the karma, 'cause it'll take me a while to get back down to 50, high karma being meaningless now and all.....
    ---
    pb Reply or e-mail; don't vaguely moderate [ncsu.edu].
  • But who's going to make the "Nanotubes Rock!" t-shirts?
  • "Don't underestimate how stupid people are."

    Speaking of which, it just occurred to me that slashdot is just a USENET newsgroup, except they can tell what browser you're using and sell page ads. sad that the web has come to this... shopping carts and newsgroup emulation.

    eudas
  • This is one of those irritating laws of physics. You can't ever destroy heat. You can spread it into a large volume, which is what the heatsink and the fan on your computer do, but it never ever goes away.

    What happens if you try to destroy heat? Whatever gadget you build to do the job will turn out to generate more heat than it destroys. In your example, you'd have to have nanospeakers - probably piezoelectric disks stuck on the end of each tube - to do the cancellation with. And driving the nanospeakers will generate more heat than is destroyed by cancelling the sound waves.
  • >What happens if you try to destroy heat? Whatever gadget you build to do the job will turn out to generate more heat than it destroys.

    wow.. congratulations on creating a perpetuum mobile.

    total heat energy to be dissipated equals x
    actually dissipated heat equals y.
    x will always be larger than y, if no extra energy is supplied.

    //rdj
  • Where proposing to use nano-technology to cool Processors down? Wouldnt it be better to use the nano-tech to MAKE the processors?
  • Of course, one might find a use for superheated steam on a spaceship, just a few that come to mind are...

    1. Propellant - make that quick getaway.

    2. Use it to power a projectile weapon to use against your enemy.

    3. Use it as the projectile weapon to use against your enemy. Sort of a super-heated water-cannon.

  • OK, so now we know Carbon Nanotubules can conduct heat, have enormous tensile and compression strength for their weight and volume, and can open portals to unseen worlds.

    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.

  • Not the heatsinks, the heatsink *paste* (Score:3)

    by ptbrown ( 79745 ) on Thursday September 07, 2000 @09:44PM (#795855)
    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.
  • Nanotubes are available commercially from Aldrich Chemical...but they aren't cheap.

    $178/g crude grade, $3248/g purified.

    Aldrich Chemical [sigma-aldrich.com]

    product numbers 519308 and 519316.

  • From all the articles I read in various publications, carbon nanotubes would solve all the world's problems! The question I have is, when will they be fabricated in mass quantities? I want my space elevator, molecule-thick knife, lightweight bulletproof clothing, and ultimate fuzzy heat sink NOW!
    ___
  • it's probably a hell of a lot cheaper

    This turns out not to be the case.

    Aldrich prices:

    Diamond, synthetic, monocrystalline powder, ca. 50 micron, 99.9% $23.10/g

    Carbon nanotubes, single-walled, CarboLex SE grade, 12-15 angstrom diameter $3248/g

  • I was thinking more along the lines of conducting the heat either: a) outside or b) into a heatsink submerged in water, or some cooler substance.

    How about into your toater oven or cofee maker? Waste not, want not!
    ___

  • Central hotspot (Score:3)

    by redelm ( 54142 ) on Friday September 08, 2000 @02:07AM (#795860) Homepage
    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.
  • at what cost though? and how will it perform vs silver based paste? you can get 77% silver based paste for $14/5.6oz...

    Smalley's group at Rice has nanotubes at $1000/g. :)
  • You could move the heat away into a bucket of water and make coffee or tea with it, on a safe distance from your computer.
  • I don't believe that you read what I had said. The design would place the carbon nanotubes through the core of the CPU, that way the CPU itself doesn't hold heat like current ones do, no matter how good of a heatsink/fan combo you have, it is the heat conducting properties of the CPU which limit the rate of heat disipation. Say the junction of the CPU and the heatsink could conduct 100 joules of heat every second, but your heat sink itself could conduct 400 joules of heat per second to the air. The limiting factor would be the cpu/heatsink junction at 100 joules/sec. Placing teh carbon nanotubes in the cpu itself could increase the rate of heat conduction to your heatsink.
  • 4. Vent it in the direction of the enemy, to scatter the beam.
  • I've a bottle of high-grade silicone oil down in the lab. Provided I can get a macroscopic quantity of nanotubes without spending a month's rent, I propose to mix them together and try it out as a heatsink paste.

    I wonder though, since the energy is carried as a vibration, whether there will be any net gain in heat transfer with the tubes in a random orientation. Maybe I should make a regular carbon control at the same time.

  • Just a technical nit... This is not exactly true, Heat can be destroyed. If you have 2 bodies at different temperature, you can hook a heat engine up between them, and convert some of the heat into some other form of energy.

    Of course, sooner or later if you use that energy it will be converted into heat, and more heat then you destroyed, but there is no law of conservation of heat.

  • But I'm not convinced. Fine, if the stuff really works like they say (and let's not forget all the other wonderful things we've been promised over the years (flying cars in the year 2000, what? cold fusion, what? personal robot slaves, what?)), that still doesn't make me rush out and buy a heatsink based on the stuff. For one thing, even if you dissipate the heat from the CPU rapidly, most computer cases have some severe limitations on how quickly they dissipate heat internally. Whether it's insufficient airflow, poof case design, or what have you, I'm not convinced that a better heatsink without a better overall heat dissipation scheme means that much. Now maybe if you make some kind of alloy or composite material for the actual chassis using this stuff, and it can cool the entire box rapidly, that would be worth my hard earned hardware budget's attention. But it's still a step in the overall right direction. Especially with the new Itanium "Easy Bake Oven heating element" chips and the Pentium 4 portable frying surface chips coming out. But would a Transmeta need this stuff?
  • Eh? Have you calculated the heat capacity of a big block of ice lately? Sheesh. Whatcha got powerin' that laser? A nuclear reactor?
  • Another approach would be to use chips to convert heat back into electricity. This seems to be (quite lofty) goal of borealis [borealis.com]

    The press release [borealis.com] describes their goals, but is a bit fluffy.

    More meat can be found on their explaination [borealis.com]page

  • Could make for more efficient heat sinks (Score:5)

    by toybuilder ( 161045 ) on Thursday September 07, 2000 @07:52PM (#795870)
    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!
  • Nanotubes are prohibitively expensive. They have a ton of uses, there's just no good way to manufacture mass quantities.

    Fsck this hard drive! Although it probably won't work...
    foo = bar/*myPtr;
  • I can see it now. Computer with built in coffee warmer. Now that's how you make some serious cash.
  • I have tons of karma to burn and your inappropriate use of the offtopic moderation choice has pissed me off.
    This is an offtopic post. A post that discusses the topic at hand is NOT an offtopic post.
    You messed with the wrong karma whore.
    --Guess Who?
  • I think you'd need a really, really big block of ice to fend off any decent-size laser attack. Really big. I don't think it would take (relatively) all that much juice to turn that block of ice into superheated steam in a few seconds.

    Maybe a more effective temporary heat sink -- like a small black hole.

    ----

  • Or better yet, use the stuff to cover the die, inside the hermetically-sealed package. Thus keeping the die itself cooler.

    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 ;-)

  • "Well, that finished them off. The atmospheric scattering compensator created a beam that used their steam cloud as the final focusing agent."

  • Heat Sinks? (Score:5)

    by Vuarnet ( 207505 ) <(moc.liamtoh) (ta) (nalim_siul)> on Thursday September 07, 2000 @07:55PM (#795877) Homepage
    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!

  • Wasn't Intel or someone else experimenting with a design that had channels in the circuits that conducted and dissipated heat so that a cooling fan would be unnecessary?

    Self Bias Resistor
    "You know you're successful when you've pissed off your parents."

  • <OT>

    uhh ya... i remember when i cheated in mechwarrior 2 and ended up with a firemoth that had 10 er lasers and can fire them continously without overheating =D

    but if you had nanotech in battletech, then someone will make a nanogun that releases nanites that eat through armor... which ruins the balance of the game. Another example of technology ruining battletech is nuclear bombs. IIRC, the storyline said something about nukes being banned by all the major houses in battletech... but that's just an excuse to make the game balanced and playable so they can sell more copies of battletech merchandise... after all, what good are "fearsome" battlemechs when a single nuke can easily take out the legions of mechs?

    </OT>

    gee, I was so offtopic there, anyway, will nanotubes be produced and sold cheaply so that average joe's power hungry AMD Firebird / Sextium III Pro w/XXX technology will come with a nanotube heatsink rather than an aluminum heatsink? It's great how nanotubes can conduct heat so well, but if the technology doesn't become affordable, then how can we benefit from it?


    Zetetic
    Seeking; proceeding by inquiry.

    Elench
    A specious but fallacious argument; a sophism.
  • But, if the material the chip is encased in was a good enough heat conductor, you could make due with much less heatsink

    Oh come on, you have the same amount of heat! You'd need the same sized heat sink - it's still AIR this is being radiated into! Actually, I'm not sure how well these things would radiate heat at the ends anyway.

    Hmmm, maybe I'm misunderstanding something here. As I understand it, the material the heatsink is made of has no effect on the rate that heat dissipates through the air once it's left the chip/heatsink. That's why I said you would need a really powerful fan. But, the rate at which heat moves from the chip/heatsink into the air at the point of contact is effected by the conductivity of the material from which the heat is radiating, right? In other words, with equal, sufficient, arbitrarily large airflow, a heatsink made out of a better thermal conductor will require less surface area than one made out an inferior conductor to achieve the same transfer, right? I doubt these nanotubes will be that material, but if taken to the extreme that relationship should hold even when you reduce the surface area to just what's on the chip, right?

    Let me know if I've missed anything, I'm relatively new to this stuff and I find it fascinating :)

  • IIRC and I may not, the Fusion reactors the Soviets and Americans are buildings, the heat generated is magnitudes higher than convential system can metallurgy can cope with... Could carbon nanotubes be part of the solution to this problem ?
  • 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
  • Problem is airflow. Too fuzzy and you stifle it. Need more than surface area for good thermal dispation. You need to be thermally 'near' the hotspot (you need to be hot), and you need lots of airflow.

    Maybe if you sandwiched the fuzz layer between the chip itself and some other surface, and then forced air - or freon - through the center of the sandwich....

  • 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've got a problem with the way moderation gets done around here.
    You see, I love /. 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.
    What I can't stand is vindictive or thoughtless moderation.
    It pisses me off to see Vladinator get moderated down as offtopic on sid=vladinator. By definition, he can't be offtopic in his own fucking sid. It pisses me off to hear people yelling "Moderate Jon Ericson down, he's a known troll!!!" when the post in question isn't a troll. It's bad moderation that is ruining this site.
    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 /. discussions. Moderating based on the posters opinion of Linux or your opinion of the poster is an abuse of this trust.
    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 /. community (which is how you get the +1 bonus after all) I feel a responsibility to attack abuses of moderation whenever I see them.
    --Shoeboy

  • Heat pipes are really nifty things were a metal tube is evacuated, then a small amount of water is placed inside. Now some of the water immediatley vaporizes until the system reaches equilibrium. When one end of the pipe is heated, this equilibrium is upset and some more water vaporizes. This induces a pressure change that travels down the pipe at the speed of sound, until the vapour cools enough to condense back into water. The water is then pumped back to the other end by cappilary action of the porous surface on the inside of the pipe. The point of all this is that heat pipes can have enourmously steep thermal gradiens. These things are used in laptops to pump the heat from the processor to the frame. I think this is a much better idea than putting a huge heat sink right on the proccesor. Just attach an adequately sized heat pipe to the proccessor and an adequately sized heat sink on the other end of the pipe. The pipe itself can be many feet long without seriously lowering the thermal gradient. Put a dense pin sink the size of the side of your computer case inplace of the side of your computer. Some manufacturer even put a heat "pipe" chamber on the bottom of a heat sink to get around the problem of the highly concentrated heat source that tiny modern procs provide. The entire heat sink is very nearly uniform in temp.

    Why aren't heat pipes used more. They make much more sense than water cooling a computer and are virtually unbreakable.
  • Fucking moderators.

    Look past your own vendettas for once.

    Yeah yeah, I know, (Score: -1, Offtopic). Fuck off.

    ______

  • 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.
  • 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?

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