New Semiconductor Coolers

An anonymous reader writes: "A new thermoelectric material is 2.4X as efficient as best existing materials. The new solid state heat pumps can provide 700 watts of cooling (nearly one horsepower) with just one square centimeter. These new materials have the potential to replace current heat sinks, thermoelectric generators and mechanical heat pumps. You can also read an article in nature."

Comments

In one word...

[codeButcher]

cool!

NPR information

[queequeg1]

There was a brief bit on NPR about this a few days ago. NPR recording

Can we get rid of the fan though?

[hattig]

With a suitably sized heatsink made of this material, can we get rid of the noisy fan, or at least replace it with a slower, quieter fan.

This would be great for those of us with 1.4GHz Athlons rumbling away in the corner.

I expect that it will start of as some kind of heat spreader material on CPUs themselves, and possibly in the base plate of the heatsink. It is probably very expensive.

Itanium will need a tonne of the stuff... :)

Re:Can we get rid of the fan though?

[drinkypoo]

With a suitably sized heatsink made of this material, can we get rid of the noisy fan, or at least replace it with a slower, quieter fan.

You're missing the point; We don't make heat sinks out of peltier junctions, we put them on top of peltier junctions. In order to keep the heat sink cool, we put a fan on them.

In other words, we will never make heat sinks out of this material. We'll simply transfer heat to them with it. Current heat sinks work fine.

More Links

[Alien54]

On the nature site, they also have full text with all the gory scientific details, and a PDF.

a couple of them in fact. (look to the bottom of the page)

A fix at the wrong end

[Junks Jerzey]

While this is neat and all, I should hope that more effort goes into lower power consumption in general. Just because there's a better way to cool high-power chips doesn't mean that such a chips are a good idea in the first place.

Someone I know who works in embedded systems recently pointed out that most CPU makers have decided to chase performance at all cost without regard to power consumption, and this is leaving embedded systems engineers up a creek.

When cooling fails

[jxqvg]

These things are going to get so efficient and semiconductors running so hot that when one of them fails the whole thing will go critical mass. Your box won't just fail, it'll burst into flames and melt into a useless bubbling pool of metal and plastic!

Re:What I am wondering

[atrowe]

The problem with these heat pumps (and Peltier coolers) is that the cooler sucks heat away from the processor side and pushes it to the exposed side of the cooler. As an unfortunate side effect, the cooler GENERATES additional heat in the process.

As an example, if your processor generates 50 watts of heat output, the cooler might generate an additional 50. The processor itself would stay cool, but you're dumping a lot of extra heat into your case, requiring even more case ventilation.

Not very practical for most users.

misleading headline - this GENERATES power

[deander2]

The body of this news item is misleading. This material can GENERATE 700 watts of electricity from only one square cm. (specifically under a 58 degree F tempature gradient).

It can also heat and cool things 2.5x more efficiently (then anything else on the market) if you push electrons through it, rather than let them come out.

Very interesting stuff, IMHO. Generating electricity from waste heat with inexpensive materials is a holy grail of sorts in a LOT of applications.

BTW, this is what the patent system was SUPPOSED to protect. True innovation.

Re:misleading headline - this GENERATES power

[Bistromat]

This material can GENERATE 700 watts of electricity from only one square cm. (specifically under a 58 degree F tempature gradient).

there's not enough energy difference in a 58-degree gradient to account for 700W per cc. if this were true, i could power Boston by replacing my oven's door with this stuff & baking a batch of brownies.*


i exaggerate, but the energy figure given is still ridiculously large.

Re:misleading headline - this GENERATES power

[markmoss]

It's not the temperature difference alone that determines the power, but the temperature difference times the heat flow. And I know of no theoretical limits to heat flow, although there are lots of practical problems...

Nature has the full scientific article. I don't understand most of it, but it does say "Thin-film thermoelements lead to large cooling power densities (PD)... We estimate a value of PD of 700 W cm-2 at 353 K and 585 W cm-2 at 298 K at the measured maximum cooling in superlattice devices compared to a value of 1.9 W cm-2 in the bulk device of Fig. 4a". That is, 700 watts/cm2 cooling at 70C (the max temperature for industrial-spec semiconductors), 585 at 25C (room temperature), and it's about 350 times as fast at pumping heat as the comparison thermoelectric material.

To actually use that cooling ability, you've got to somehow couple 700W/cm2 heat into one side and remove rather more heat from the other side. (Or to generate 700W power, you've got to couple more than 700W to one side and remove the waste heat from the other.) A TO-220 power transistor has an approximately 1 cm2 metal plate on the back to contact the heatsink; take a really big heatsink and really good thermal paste and really torque down the screw clamping them together, and it will handle almost 20W. 700W would fry the transistor core instantly, before the backplate even got warm. The coupling between a GHz Pentium and heatsink/Peltier refrig/fan must be better than this, but not THAT much better. Lots of luck!

By the way, anyone notice that the reporter doesn't know the difference between "efficiency" and "effectiveness".

Idea

[Pyrosz]

Due to the problem of fitting larger heatsinks and fans (damn loud things) onto ever smaller motherboards and chips, is it not time to re-think this idea? Would it not be possible to use this new material to pump the heat from the chip to the side of your case? The side of your case could be a very large heatsink. It would require small fins and might even improve the looks somewhat. It would not get hot due to the surface area and heat dispersion. Why use a small (relative) heatsink and excesivily (sp?) loud fan to cool the chip when you already have a large heat release area? Anyway, just a thought.

It can do what now?

[BillyGoatThree]

"...can provide 700 watts of cooling (nearly one horsepower) with just one square centimeter..."

Can someone explain exactly what this means? I haven't reach thermodynamics in my physics studies yet.

I mean, I understand "700 watts"--that's 700 Joules/second. So presumably a cm^2 of this material can "cool" 700 Joules of heat energy every second. But surely the limiting factor here is how quickly the *air* (or other surrounding medium) can *accept* energy, not how fast the device can pump it out....right?

I saw this same article over at bottomquark except they had a new release linked as well. The release claimed that just a few dots of this material on a chip would replace (plus some!) a regular heat sink. How on earth could that be? What about the areas where dots aren't located?

Re:It can do what now?

[WNight]

I agree with your conclusions.

This seems like a great way to quickly remove heat from a small area and spread it to a large area. You'll still have a lot of waste heat on the hot side of this and I'm sure you'll need a heatsink on there. Large than before in fact because this appears to be a powered thermocouple like a Peltier cooler which means it should generate waste heat as well.

The benefit though is that heatsinks become more efficient as the temperature gradient goes up, so we should still be able to get the heat into the air and then out of the case. And because this thermocouple maintains a rather large gradient we should be able to keep the CPU that much cooler.

As for the little dots of it, etc... I think what they mean is that inside the CPU core you'd have little dots of this being used to pump heat away from the main heat generating areas directly into the heat-spreader on top of the chip. The only other way to do it is let the heat diffuse through the whole core and then into the heat spreader.

So this would be a lot better at putting heat in manageable areas (the heatsink) but it isn't magic, you couldn't put a bit in a sealed package and have heat magically disappear.