anvilmark writes "ABCNews has an article about a new carbon based thermal conducting foam. Very pricey to produce but has 4-5 times the efficiency of copper at 1/5th the weight of aluminum. ORNL technical documentation available here and here. Sounds like the perfect heat sink shim to me."
MIT developed army suit
by
SteakandcheeseUm
·
· Score: 3, Interesting
the end of the article states
. Both Klett and Conway have started doing research for the government to adapt the foam for use in "personal cooling devices" for military personnel.
I wonder if they will try to intigrate this into the Nanotech suit that is being developed by MIT? or is this before that
Great heat pipe material
by
vought
·
· Score: 4, Interesting
You could make a nicely-shaped heat pipe with this stuff, tranferring heat from say, a processor to the outside of the case easily. I'm sure hardware and environmental engineers will have a ball with this stuff if it can be produced relatively inexpensively.
Research and development
by
reflexreaction
·
· Score: 5, Insightful
Klett admits that it is highly unlikely the foam will break out of the lab and into widely available commercial applications anytime soon.
Stories like this have always annoyed me. You always hear about the possible development of an item that is four or five (or however many years) away from being put into commercial application but after that you never hear about it. Or if it is used commerically you never hear about where it has been put into use. I work in the scientific field and I almost never hear about an exciting development after it's initial announcement.
The one exception to this is pixie dust that has allowed for the phenomeonal growth of hard drives. Oh well.
--
We had to destroy the sig to save the sig.
Re:Research and development
by
darkonc
·
· Score: 3, Insightful
In many cases, the great scientific breakthrough will point people into a general direction that produces something better than the original breakthrough...
(think of basic research as a bunch of blind men trying to hit a bullseye... The breakthrough is hitting the board. Once people know where the board is, someone else is likely to actually hit the bullseye -- so you hear about the person who first hits the board, and the person who hits the bullseye, but it's rare that the connection between the two events make it through the "15 seconds of fame" filter of media editing.
-- Sometimes boldness is in fashion. Sometimes only the brave will be bold.
...noone makes a batch of cofee cups from
this material by mistake...
-mi
-- In Soviet Washington the swamp drains you.
Oh come on, we had these when I was a kid..
by
Bowie+J.+Poag
·
· Score: 3, Funny
"Themoconductive carbon foam"? Puh-leaze. We had this shit when I was a kid. Magic Snakes -- You put em on the sidewalk and light them on fire. Just like the one that nearly wiped out South Park last 4th of July.:)
We were swimming in the stuff!;)
-- Bowie J. Poag
Re:Dumb question
by
NanoProf
·
· Score: 3, Informative
If you heat it up hot enough in the presence of
oxygen, it will burn. So will a diamond, for that
matter. The 3000 degree heat treatment
that they use during synthesis must be done
in an inert atmosphere. Coal burns more
easily than diamonds, I'd guess, but both
are carbon with fairly similar heats of
combustion. Local carbon bonding comes in
two main forms, sp2 (triangular) and sp3 (tetrahedral) bonding; the binding energies of
the two are quite close and both will happily
burn in the presence of oxygen, at high
temperatures.
-- Curtains for windows?
One problem.....
by
Veramocor
·
· Score: 3, Interesting
If you read the literature fully you'll find that the thermal conductivity is directionally orienented. So if you go 90 degrees in the other direction of the fibers it basically has a thermalconductivity of 1/5 aluminum. (see table 1 of the second ducument).
This may not matter for applictions like a processor, but cooling other objects with more of a 3-d surface may be a problem.
-- Veramocor
Re:Goofy comparisons
by
GigsVT
·
· Score: 4, Informative
Uh, wrong, try again.
Where did you find this "fact", the encyclopedia retardica?
Alumina, i.e. sapphires et al, have high thermal conductivity, and yet are almost total insulators. QED.
Please, please, try to check your facts. We all make mistakes, but I have seen so many totally wrong posts in this article that it is depressing me.
-- I've had enough abrasive sigs. Kittens are cute and fuzzy.
I am utterly amazed....
by
dr_db
·
· Score: 5, Informative
That so many posters confuse a heat conductor with a heat pump.
Come on - this will not be "keeping your fridge colder" or "cooling your drinks". It will just make whatever it's attached to move to the ambient temperature faster. Wrap it around your fridge and you will have sour cream in your milk, etc. Or else the coldest kitchen around.
Either it's a brain dead friday, or the collective IQ of Slashdot is lower than I assumed over the last few years.
Re:I am utterly amazed....
by
AnalogBoy
·
· Score: 4, Insightful
The collective IQ has dropped significantly. About now, the 2nd generation of slashdotters are making their exodus to other news sites - or - worse - the real world. By leaving the collective and making the ratio of clue decreases, leaving the bottom-rung stallmanite slashdrones to pick up the slack, so to speak. in addition the average age is now lower.
Perhaps we should charter a report on slashdot groupthink. if i were in college i'd do it.
Alternately, i accept the idea that it is indeed brainded friday.
[Disclaimer - Due to the extraction of a wisdom tooth today and the subsequent mind-numbing hydrocodone, i do not claim responsibility for the content or readability of my above post. It makes sense as i type it. thats all that matters. =) ]
Re:I am utterly amazed....
by
shaar
·
· Score: 3, Informative
uhm... a fridge is a heat pump that takes heat from the inside and moves it outside. so wrapping this around your fridge (back of the fridge in particular) will give you a really _hot_ kitchen, and a really really cold fridge (given no hardware failure). The body of the fridge would do a decent job of insulating the outside from the inside, the conductor will just help the heat pump.
For somebody lambasting posters for not having a good grasp of heat transfer, you sure didn't spend much time thinking about it.
Re:I am utterly amazed....
by
Dirtside
·
· Score: 3, Funny
leaving the bottom-rung stallmanite slashdrones
Yeah, but you're still here. I blame the hydrocodone.:)
-- "Destroy science and religion. Science would re-emerge exactly the same; but not religion." - Penn Jillette, paraphrased
Re:I am utterly amazed....
by
hyrdra
·
· Score: 3, Insightful
My god! The TRAVESTY! We all must be utterly retarded if we don't know the difference between a heat pump and a heat conductor!
Jeez, what a jerk. There are always common misconceptions, even among geeks. We're all here to learn and gain more knowledge via interesting and thought provoking conversation on Slashdot.
So don't come off like an ass hole. I'm sure someone has set you straight in something embarrassingly stupid that you should've known.
--
"I'll just chip in a bit for RedHat: I actually have that installed on my university machine." - Linus, '95
Re:I am utterly amazed....
by
digitalunity
·
· Score: 3, Insightful
No, I'm serious. And I really am an elitist snob, a perfectionist, an intravert, as well American(good guess; I didn't presume that about you though).
My biggest problem with the average American is complacency and apathy. In this day and age(I'm only 20, btw) people are fucking ecstatic about spending their last dime on status symbols they can't afford. It's consumerism at it's worst. That is why I am such a snob. I'm 20; I own 2 cars outright. I work very hard, but I'm not a workaholic. I have a good job, and I'm surrounded by low income white trash(excuse the expression) who can't get a better job because they don't care enough to excersize their minds as much as their wallets.
Research studies have shown that it is never too late to increase your brains capacity for knowledge or learn new skills. They would all drown in their own self created pity-pools if they weren't so apathetic about their lives.
As far as Mensa goes, I took the online pretest and got 29 out of 30 in 16 minutes. After reading about Mensa, they came off even more elitist than I yet had less to back it up. That, and they seemed a little droll. The last time I took my IQ test, I scored in the top.68%:)
-- You can't legislate goodness. Let each to his own destiny, by will of his freely made choices.
carbon based thermal conducting foam, huh? I wonder if I can encase someone in this stuff and hang em up on the wall in my desert palace...
-- Don't trust a bull's horn, a doberman's tooth, a runaway horse or me.
Great for Cooling UltraDense Clusters & Handhe
by
LuxuryYacht
·
· Score: 3, Interesting
This is a great material for cooling supercomputers and ultra-dense servers that would otherwise require more elaborate elaborate liquid cooling systems.
The handheld and laptop market is another area that could really use this to keep the cpu and graphics processor cool.
This sounds like it takes highly thermally conductive polymers like CoolPoly to another level. .
-- Quidquid latine dictum sit altum viditur
think outside the beige box...
by
llamalicious
·
· Score: 3, Interesting
add-on heat conductors for improving air-ventilation on disc brakes... make make WRX even happier:)
useful in supersonic aircraft... conduct the heat away from leading edges much faster than normal.
c'mon, join in... what other real-world apps could this be useful for. if the price can come down, and the production can come up... I can think of a lot more places this stuff would make sense.
I worked for the manufacturer - Poco Graphite
by
chrisflusche
·
· Score: 3, Interesting
I worked for POCO Graphite in Decatur, Texas up until 6 months ago. POCO is the only licensed manufacturer of graphite foam (POCOFoam is their name for it).
This stuff isn't just good for a heat sink shim - IT CAN EASILY REPLACE YOUR ENTIRE HEATSINK AND FAN! But- heatsinks are only the beginning. POCO has made prototype car radiators out of this stuff that are 6 inches by 8 inches by 1 inch - AND THEY WORK EXTREMELY WELL!
To get an idea of just how well POCOFoam transfers heat, check out this video clip http://www.pocofoam.com/images/foam.mov. You will be highly impressed - I guarantee!
Re:shim..sink - what's the difference?
by
Osty
·
· Score: 3, Informative
A shim is a small plate composed of thermally conductive material that you put between an FCPGA CPU and the heat sink. It has holes for the chip and the other parts of the CPU that rise above the rest.
Nope. A shim is generally not thermally conductive (and better damn well not be electrically conductive...), since it doesn't matter whether it is or not.
The idea is to increase the amount contact surface area between the CPU and the heatsink.
Again, wrong. The idea is not to increase the amount of contact surface between the CPU and the heatsink, as this would be impossible to do, unless you made the CPU itself larger -- heat only radiates off of a CPU from the little rectangular core in the middle; the ceramic surrounding the contact point has little to no thermal conductivity. Instead, the idea is to give the heatsink a larger area to which to apply pressure. This means it's going to be more difficult (though not impossible) to chip the CPU core if you're using a shim than if you're not. Shims only became popular with the Athlon Thunderbird chips that were trivially easy to break with a sloppy heatsink install. Since those shims were made out of copper (bad! that's electrically conductive, which means you could very easily short out your CPU), many of the more clueless overclockers instantly thought "copper == cool", and thus assumed that shims were another way to lower their CPU temps by a couple more degrees. They were wrong.
While not the same thing, carbon has been used as a heatsink interface material for years. My DEC Alpha came with a Grafoil pad to use between the processor and the heatsink, in lieu of heat sink paste. It's apparently spongy graphite made into a flexible pad.
Re:Double braindead, it seems
by
jaoswald
·
· Score: 3, Informative
Sorry, try again.
Conduction through a heat conductor can be represented with the thermal equivalent of Ohm's law. Warmth of a soft drink above room temperature is equivalent to a charged capacitor, where you can consider the room to be ground.
In your drink experiment, a drink warmer than room temperature will equilibrate to room temperature eventually. The speed with which it will equilibrate with a time constant
tau = RC
where R is the thermal resistance, C the heat capacity of the soft drink.
Lower R (better thermal conductivity) means the time is faster. However, when all is said and done, the drink and the room are all the same temperature, and that temperature does NOT depend on the thermal conductivity. It depends on the relative heat capacities. Given that the room is much bigger than the drink, its heat capacity is much larger, so the change in room temperature is negligible. (The amount of heat in a warm drink is the amount of heat in an infinitesimally warmer room.)
The only thing that could get signficantly hotter is a cold drink in a warm room.
I think you need to study a bit harder, Mr. PhysicsGenius.
Re:Not all that hot...
by
jmichaelg
·
· Score: 4, Informative
....PURE copper runs 350-400 W/m-K...pure copper isn't usually used, an alloy is.
I was talking about copper alloys. At room temperature, Both copper 110 and 101 alloys have a thermal conductivity of 391 W/m-k. Phosphorous laced copper alloys will drop you down to around 380. The only reason I happen to have these numbers is I'm currently working on a heat sink.
The news article that got this thread going had so many inaccuracies that I'm prone to think that a marketeer at Poco got somebody at ABC News all excited with hype. Given the foam's poor thermal conductivity, I seriously doubt the national security agency is using it as a heat sink unless, possibly, it's on a satellite. But if that were the case, Poco would have been nda'd and the story wouldn't have made light of day. The story smells of marketeer-speak.
You're right about the density uneveness. There are several elemental foams available that have very uniform density. You can get metal silver foams for applications where surface area is very important. John Carnack (of doom fame) has been playing around with silver foams as a catalyst for hydrogen peroxide to drive his rocket.
However, as a heatsink, foams don't fare well because heat transfer is partially a function, not of surface area as you assert, but of the cross-sectional area perpendicular to heat flow. Foams have lots of surface area which is nice for catalysts but have lousy cross-sectional areas which is what is needed to transfer heat from one edge of the foam to the other. Once the heat is spread out over a heatsink's mass, THEN the heatsink's surface area comes into play. Foams suffer as heatsinks because they can't move heat well from the primary hot spot to their extremeties.
Having said all that, there's some experimental work going on with carbon heat sinks that are configured in standard heatsink geometries. Anandtech's Cebit report shows a few pictures of some carbon heatsinks. Carbon is attractive, because as an element, it does show promise. As a working material, it's difficult. If carbon nanotubes ever get out of the lab, there'll be a huge change - they've got great thermal conductivity - somewhere in the thousands of watts.
Slashdot Mirror
the end of the article states
. Both Klett and Conway have started doing research for the government to adapt the foam for use in "personal cooling devices" for military personnel.
I wonder if they will try to intigrate this into the Nanotech suit that is being developed by MIT? or is this before that
You could make a nicely-shaped heat pipe with this stuff, tranferring heat from say, a processor to the outside of the case easily. I'm sure hardware and environmental engineers will have a ball with this stuff if it can be produced relatively inexpensively.
Klett admits that it is highly unlikely the foam will break out of the lab and into widely available commercial applications anytime soon.
Stories like this have always annoyed me. You always hear about the possible development of an item that is four or five (or however many years) away from being put into commercial application but after that you never hear about it. Or if it is used commerically you never hear about where it has been put into use. I work in the scientific field and I almost never hear about an exciting development after it's initial announcement.
The one exception to this is pixie dust that has allowed for the phenomeonal growth of hard drives. Oh well.
We had to destroy the sig to save the sig.
In Soviet Washington the swamp drains you.
"Themoconductive carbon foam"? Puh-leaze. We had this shit when I was a kid. Magic Snakes -- You put em on the sidewalk and light them on fire. Just like the one that nearly wiped out South Park last 4th of July.
We were swimming in the stuff!
Bowie J. Poag
If you heat it up hot enough in the presence of oxygen, it will burn. So will a diamond, for that matter. The 3000 degree heat treatment that they use during synthesis must be done in an inert atmosphere. Coal burns more easily than diamonds, I'd guess, but both are carbon with fairly similar heats of combustion. Local carbon bonding comes in two main forms, sp2 (triangular) and sp3 (tetrahedral) bonding; the binding energies of the two are quite close and both will happily burn in the presence of oxygen, at high temperatures.
Curtains for windows?
If you read the literature fully you'll find that the thermal conductivity is directionally orienented. So if you go 90 degrees in the other direction of the fibers it basically has a thermalconductivity of 1/5 aluminum. (see table 1 of the second ducument).
This may not matter for applictions like a processor, but cooling other objects with more of a 3-d surface may be a problem.
Veramocor
Uh, wrong, try again.
Where did you find this "fact", the encyclopedia retardica?
Alumina, i.e. sapphires et al, have high thermal conductivity, and yet are almost total insulators. QED.
Please, please, try to check your facts. We all make mistakes, but I have seen so many totally wrong posts in this article that it is depressing me.
I've had enough abrasive sigs. Kittens are cute and fuzzy.
That so many posters confuse a heat conductor with a heat pump.
Come on - this will not be "keeping your fridge colder" or "cooling your drinks". It will just make whatever it's attached to move to the ambient temperature faster. Wrap it around your fridge and you will have sour cream in your milk, etc. Or else the coldest kitchen around.
Either it's a brain dead friday, or the collective IQ of Slashdot is lower than I assumed over the last few years.
carbon based thermal conducting foam, huh? I wonder if I can encase someone in this stuff and hang em up on the wall in my desert palace...
Don't trust a bull's horn, a doberman's tooth, a runaway horse or me.
This is a great material for cooling supercomputers and ultra-dense servers that would otherwise require more elaborate elaborate liquid cooling systems.
The handheld and laptop market is another area that could really use this to keep the cpu and graphics processor cool.
This sounds like it takes highly thermally conductive polymers like CoolPoly to another level.
.
Quidquid latine dictum sit altum viditur
add-on heat conductors for improving air-ventilation on disc brakes... :)
make make WRX even happier
useful in supersonic aircraft... conduct the heat away from leading edges much faster than normal.
c'mon, join in... what other real-world apps could this be useful for. if the price can come down, and the production can come up... I can think of a lot more places this stuff would make sense.
I worked for POCO Graphite in Decatur, Texas up until 6 months ago. POCO is the only licensed manufacturer of graphite foam (POCOFoam is their name for it). This stuff isn't just good for a heat sink shim - IT CAN EASILY REPLACE YOUR ENTIRE HEATSINK AND FAN! But- heatsinks are only the beginning. POCO has made prototype car radiators out of this stuff that are 6 inches by 8 inches by 1 inch - AND THEY WORK EXTREMELY WELL! To get an idea of just how well POCOFoam transfers heat, check out this video clip http://www.pocofoam.com/images/foam.mov. You will be highly impressed - I guarantee!
Nope. A shim is generally not thermally conductive (and better damn well not be electrically conductive ...), since it doesn't matter whether it is or not.
Again, wrong. The idea is not to increase the amount of contact surface between the CPU and the heatsink, as this would be impossible to do, unless you made the CPU itself larger -- heat only radiates off of a CPU from the little rectangular core in the middle; the ceramic surrounding the contact point has little to no thermal conductivity. Instead, the idea is to give the heatsink a larger area to which to apply pressure. This means it's going to be more difficult (though not impossible) to chip the CPU core if you're using a shim than if you're not. Shims only became popular with the Athlon Thunderbird chips that were trivially easy to break with a sloppy heatsink install. Since those shims were made out of copper (bad! that's electrically conductive, which means you could very easily short out your CPU), many of the more clueless overclockers instantly thought "copper == cool", and thus assumed that shims were another way to lower their CPU temps by a couple more degrees. They were wrong.
While not the same thing, carbon has been used as a heatsink interface material for years. My DEC Alpha came with a Grafoil pad to use between the processor and the heatsink, in lieu of heat sink paste. It's apparently spongy graphite made into a flexible pad.
Sorry, try again.
Conduction through a heat conductor can be represented with the thermal equivalent of Ohm's law. Warmth of a soft drink above room temperature is equivalent to a charged capacitor, where you can consider the room to be ground.
In your drink experiment, a drink warmer than room temperature will equilibrate to room temperature eventually. The speed with which it will equilibrate with a time constant
tau = RC
where R is the thermal resistance, C the heat capacity of the soft drink.
Lower R (better thermal conductivity) means the time is faster. However, when all is said and done, the drink and the room are all the same temperature, and that temperature does NOT depend on the thermal conductivity. It depends on the relative heat capacities. Given that the room is much bigger than the drink, its heat capacity is much larger, so the change in room temperature is negligible. (The amount of heat in a warm drink is the amount of heat in an infinitesimally warmer room.)
The only thing that could get signficantly hotter is a cold drink in a warm room.
I think you need to study a bit harder, Mr. PhysicsGenius.
....PURE copper runs 350-400 W/m-K...pure copper isn't usually used, an alloy is.
I was talking about copper alloys. At room temperature, Both copper 110 and 101 alloys have a thermal conductivity of 391 W/m-k. Phosphorous laced copper alloys will drop you down to around 380. The only reason I happen to have these numbers is I'm currently working on a heat sink.
The news article that got this thread going had so many inaccuracies that I'm prone to think that a marketeer at Poco got somebody at ABC News all excited with hype. Given the foam's poor thermal conductivity, I seriously doubt the national security agency is using it as a heat sink unless, possibly, it's on a satellite. But if that were the case, Poco would have been nda'd and the story wouldn't have made light of day. The story smells of marketeer-speak.
You're right about the density uneveness. There are several elemental foams available that have very uniform density. You can get metal silver foams for applications where surface area is very important. John Carnack (of doom fame) has been playing around with silver foams as a catalyst for hydrogen peroxide to drive his rocket.
However, as a heatsink, foams don't fare well because heat transfer is partially a function, not of surface area as you assert, but of the cross-sectional area perpendicular to heat flow. Foams have lots of surface area which is nice for catalysts but have lousy cross-sectional areas which is what is needed to transfer heat from one edge of the foam to the other. Once the heat is spread out over a heatsink's mass, THEN the heatsink's surface area comes into play. Foams suffer as heatsinks because they can't move heat well from the primary hot spot to their extremeties.
Having said all that, there's some experimental work going on with carbon heat sinks that are configured in standard heatsink geometries. Anandtech's Cebit report shows a few pictures of some carbon heatsinks. Carbon is attractive, because as an element, it does show promise. As a working material, it's difficult. If carbon nanotubes ever get out of the lab, there'll be a huge change - they've got great thermal conductivity - somewhere in the thousands of watts.