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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."
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...
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.
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.
...
The heating was gradual. There's a pretty well known fact that if you put a frog in cool water, then gradually heat it, it will never jump out but be boiled alive. To a lesser extent our own sensory systems work the same; they react to differentials rather than absolute values.
In this case, the machine probably got warm, but not so quickly nor so much that it ever became really uncomfortable (and if your attention is fixed on your work, the threshold is even higher). Also, to some extent you can exchange temperature for time in getting an equivalent burn; ie. while something needs to be scalding hot to burn you with just a touch, it can be considerably cooler if it's in contact for a long period.
Trust the Computer. The Computer is your friend.
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.
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
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