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Sandia's Smart Heat Pipe
An anonymous reader writes "Science Blog is reporting a story from Sandia National Laboratory, best known for its nuclear weapons research. "Evacuating heat is one of the great problems facing engineers as they design faster laptops by downsizing circuit sizes and stacking chips one above the other. The heat from more circuits and chips increase the likelihood of circuit failures as well as overly heated laps. "Space, military, and consumer applications, are all bumping up against a thermal barrier," says Sandia researcher Mike Rightley, whose newly patented "smart" heat pipe seems to solve the problem. The simple, self-powered mechanism transfers heat to the side edge of the computer, where air fins or a tiny fan can dissipate the unwanted energy into air."
No matter what i do my laptop is one hot sucker! Especially when i have it docked, whoever made my docking station (all from Dell) they decided to block my fans on the back of the laptop when I dock it.
Sometimes the better thing is simply a more well though out design, all this newer technology is good too of course but people need to stop substituting higher technology for stupidity.
... for this guy.
Q.
In colder climates, the heat could be dumped into hand warmers rather than undesirably into fabric and the flesh beneath.
colder clients being the 66F computer room? i know 66F isn't that cold, but when you're drinking a code red, my hands get quite numb in there. be nice to be able to flip a switch and redirect that heat up into the keyboard instead of the edge...
When they have found a way to channel the heat into keeping my cup of coffee warm while I'm reading then i'll be intrested.
I see nothing in this article that distinguishes this "smart" heat pipe from standard heat pipes that have existed for quite some time.
Yes, this technology is significantly better than air being blown over a heatsink on a CPU.
No, it's nothing new. Shuttle small-form-factor PCs anyone? And Dell Inspiron 8x00 series laptops too. Probably other laptop manufacturers are also already using heat pipes.
retrorocket.o not found, launch anyway?
news flash, more advanced refrigerator.
Happy now???
Damn Joint Strike Fighter, its just a more advanced
Wright Flyer, no news here.
Damn AIDs vaccine, they are just repeating Dr Jenner's smallpox vaccine.
Damn airconditioning, its just a reverse campfire.
Damn,... well you get the idea.
we may not be interested in this type of news, but I this as a great stepping stone for advanced and more powerful machinery. I always heard about computers, for instance not going past certain speed in Mhz because of various factors, one of them being the amount of heat it generates. So hats off to all the people that work hard to make life better for others.
I remember sitting in on a presentation of heat pipe theory and applications.
The article talks about how the methanol vaporizes at one end, and condenses at the other. Then the liquid wicks back to the first end, where it can be vaporized again. You don't necessarily have to use methanol; the coolant is varied according to the temperature range you operate in.
The pipe pressure is carefully set so that the vaporization takes place at the optimal temperature. Usually these pipes are used in a vertical configuration, so that the vapor rises and gets to the other end more quickly, and the condensate sinks to other end quickly. The heat pipe behavior is then kind of like a passive heat diode.
A use for heat pipes was presented; apparently a lot of structures were sinking on the Alaska pipeline. When the ground was frozen, everything was fine...but the permafrost was receding in the warm months. The solution was to keep the ground frozen all the time, by removing heat from about 20 feet down. Heat pipes were constructed with a vaporization point at the desired temperature, and sunk into the ground at the problem areas. The ground stayed frozen, and the problem was solved.
...
Turning energy into light isn't 100% efficient either..
I wonder what else designers could do with that extra heat energy. If these heat pipes turn methanol into vapor, carry it to heat fans, then recondense it (due to heat loss) back into liquid.... isn't this process quite similar to how turbines work with steam? I wonder how much power could be gleaned from the extra heat. Maybe someone could design a tiny electrical generator. I doubt you could run anything significant off the power output, but I'm sure there could be some use for it, rather than simply letting that extra energy go to waste.
Why the hell do we insist on using Intel heat pumps in our laptops anyway?! There are any of a dozen different non-Intel chips that are nearly as fast as a decent P-III (or, at least, from the user's perspective) that don't need heatsinks at all! MIPS, ARM (ok, even StrongARM and XScale), SH, ...
Oh, wait, Bill doesn't want to support Windows on those chips. My bad. He'd rather force the rest of the industry and users to deal with crappy, Intel-specific problems like heat and power consumption than construct a product that's actually well-designed and portable. Yea, that's "innovative".
b.g.
b.g.
Glad it's all done for a good cause. I just hope it's tax deductible
/^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$/i
Or your skin.
7 November 2006: The day Americans realized corruption and incompetence weren't addressing 11 September 2001
In a fridge you have coolant moving through pipes at high pressure, the pressure is dropped which then causes it to suck heat out of something( ie your food), the heat is then dissipated thorugh a heat exchanger and then a compressor recompresses the fluid. A refridgeration cycle does not work without a compressor or it would defy the laws of thermodynamics.
This is however closer to a more advanced heat fin technology, heat fins are used to wick heat away from a heat source, but eventually a point in the fin becomes too cold to tranfer heat and making the fin longer doesnt' do you any good, so what do you do now?
Use a heat pipe to move the heat form one place to another, namely another set of fins, or the same fins to get more use out of their length.
So what is the main difference between your fridge and a heat pipe, one sucks energy out of something , making it colder then room temperature, and another one transports heat to another source but can never make it cooler then room termperature.
/.
This guy may have had the external vents in the wrong location.
On the other hand the extra heat vented to the outside edges could be a handy deterent to theft, just change from sleep mode to heat mode.
And I'm eager to Evaluate the new George Foreman laptop.
There really isn't much liquid in these. If you shook one, I doubt you'd even hear a slosh. The heat pipes work by adjusting the pressure in the pipe so that the methanol is teetering between liquid and vapor state. So technically the heat pipe moves methanol "steam", and the liquid at any time is measured in droplets.
They work most efficiently in a vertical configuration (warm vapor rises, cool droplets fall), so Sandia's work is very useful: they are developing more efficient ways to transfer the liquid back to the hotspot in a horizontal configuration, via capillary action instead of gravity.
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One of the largest applications of "heat pipes" is in the Alyeska Pipeline. The oil they're moving is hotter than the permafrost supporting the pipe. If the permafrost melts... well, we can guess what happens.
So if you look at the picture on the site, the heat pipe is actually built into the support structure of the pipe joints. The little vanes on the posts wick away heat that is absorbed from the ground. They use a substance that has a very low vapor pressure in order to capitalize on the energy released in the latent heat of vaporization and condensation of the anhydrous ammonia (caused by the cold Alaska air circling around the vanes). You can find the details of this huge heat-pipe installation on their Web site.
Pretty cool (literally)!
TTFN
This device (as is says at the end of the article) uses capillary action to move the cooling liquid from the hot side to the cool side. It doesn't say if this is more efficient than phase change. I expect that it would work better in non-stationary applications, where a phase change material would just get mixed up. They list military wearables as a potential application.
I have a Shuttle SS51G w/ P4-2.533 +1G DDR and I'm very happy with it. Heatpipe keeps inside surprisingly cool and is exceptionally quiet. Some have replaced the fan and fan grill or modified the case itself to lower the noise even further.
I read the article, and it doesn't say how this is different from existing heat pipes. My Dell Inspiron 8200 uses a heat pipe to move heat from the CPU to a radiator in the back. The Shuttle lunchbox machines use heat pipes to get heat to a large heatsink in the back. You've been able to buy heat pipes to speed cooking the thanksgiving turkey for years.
What's the difference between them and this? They talk about technology but to those of us who don't know the specifics of *traditional* heat pipe manufacture, it means nothing.
It's more like living in the past. Early refrigerators didn't use electrical compressors and such. Your Grandmother's refrigerator used a pilot flame to do its cooling. Sure, it wasn't able to cool and freeze quite as well modern refridgerators do but, it still kept food cold and made ice.
How cool is that, to use a flame for refrigeration? It's so cool that it is still used today in things like Recreational Vehicle refrigerators. See here.
Existing heat pipes already use capillary action. I remember a while ago looking at info on heat pipes out of curiosity, and I saw a number of descriptions of various wicks that were in use, and this doesn't appear to be anything new, except thay maybe they've made slightly more efficient wicks.
Even these new heat pipes almost surely use a phase change - It's most likely possible to do it without a phase change, but far less effective/efficient. Current heat pipes use a phase change combined with capillary action - Gas vaporizes on heat source, condenses at radiator, and is wicked back. Heat pipes can be made without wicks, but they are orientation-sensitive - i.e. the condenser must be above the evaporator so gravity will bring the condensed medium back to the heat source. The Shuttle may not use a wick since the condenser is higher than the CPU, but in Dell laptops they are even, I'm positive that laptop heatpipes already use wicks.
retrorocket.o not found, launch anyway?
Read the whole article, it is different. The difference is that:
1) They're using methanol, which at least some of the current commercial heatpipes don't.
2) They're using some sort of lithography to carve micron-scale curved pathways into the inside of the tubing. These are customized in order to wick the methanol to the correct locations. This allows them to really "shape" the methanol flow for much better efficiency (send 30% methanol to hot spot A and 70% to hot spot B, and release the heat at sink spot C), instead of just having the vapors/liquids roam around as they choose. This is a boon for any heatpipe, but especially if you have an embedded device that might need complex heatpipe routing to/from possibly multiple heat sources and heat sinks.
11*43+456^2
Conduction is heat transfer thru direct contact. You touch the stove, it burns your skin.
Convection is the transfer of heat via a moving medium. Air at the earth's surface is warmed by the sun's radiation, causing the air to rise. The heat is then transferred to the surrounding cold air, which causes the previously warm air to sink back down.
Radiation if the transfer of heat via electromagnetic radiation. All objects above absolute zero emit some form of EM radiation in proportion to the fourth power of their absolute temperature. Also involved is a coefficient that depends on how close a radiator is to an ideal 'black body' - ie a perfect radiator. See Stefan-Boltzmann equation Inet = e*s*A(T^4 - T0^4) where Inet is the net power radiated in Watts, e is the emissivity coefficient, s is Stefan's constant = 5.6703 x 10-8 W/m^2 K^4, A is the area, and T is the absolute temp and T0 is the ambient temp. (To get the total radiation emitted, set T0 = 0). The peak wavelength of the radiation is given by Wein's displacement law, lambda = 2.898 mm * K / T, where the 2.898 mm * K is a universal constant and T is the absolute temp of the object.
For example, a person has about 1.4m^2 of skin at 33C = 306K. If you assume they're a perfect radiator, in a room at 20C the person is emitting 111W of power, net. The emission peak wavelength is approx 9.5 um, which is in the part of the EM spectrum called "infrared".
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
Zero-g is also a factor. Lovell actually commented in his debriefing that you could get warmer if you didn't move. A small blanket of warm air would form around you, and since there was not much to move it around (all the fans being shut off) it would just stay there. Then you'd move and you'd be freezing again.
You can only drink 30 or 40 glasses of beer a day, no matter how rich you are.
-- Colonel Adolphus Busch
It is also different in that they are using a phase-change heat transfer. When most heat pipes boil the water they are completely ineffective.
Also, traditional heat pipes rely on elevation differences to maintain flow.
If it was a heat pipe, it was probably not solid copper, though it looked like it. It would be a copper tube filled with a volatile liquid. Liquid evaporates at the hot end, diffuses to cool end where it condenses, transferring heat as it does so. But most of them looked solid.
This invention just looks (from the uninformative article) as if they hae some improvements on the mechanical structire and on helping the methanol get thr right idea about where to flow (cappillaries with "one way" structires, I would guess).
As said elsewhere, only incremental. But then, the latest Pentium is "only incremental" on the original 386 - but thos increments have taken us a long way.
Consciousness is an illusion caused by an excess of self consciousness.
As I mentioned in another post, phase-change heat transfer in heat pipes is old hat. So is using a wick to allow for the heat pipe to work without an elevation difference. For an example of the latter, see the aforementioned Dell Inspiron 8200. Has no problem working with the laptop level, or even with the laptop tilted backwards (i.e. evaporator above condenser)
retrorocket.o not found, launch anyway?
Don't get me wrong, an interesting thought experiment, but given the losses in power generation its not practical.
Agreed.
I think you would get more bang for the buck by improving the efficiency in the laptop components themselves so that they don't put out so much heat - which is exactly what is done. If you get a top-of-the-line laptop you'll need insulated pants to avoid 2nd degree burns, but if you get a new laptop built for battery life (and not performance) then you'll find it runs much cooler.
The reason for the heat bleed is that they are always rushing to get the fastest processor out - by the time they can make it cooler nobody wants it.
If one were to do the math, the wasted heat can't be more than a few watts at most, and there isn't a whole lot you could do with that even if you could efficiently turn it to electricity at a high enough voltage.