Quantum refrigerator offers extreme cooling and convenience

Mar 06, 2013
Quantum refrigerator offers extreme cooling and convenience
NIST's prototype solid-state refrigerator uses quantum physics in the square chip mounted on the green circuit board to cool the much larger copper platform (in the middle of the photo) below standard cryogenic temperatures. Other objects can also be attached to the platform for cooling.

Researchers at the National Institute of Standards and Technology (NIST) have demonstrated a solid-state refrigerator that uses quantum physics in micro- and nanostructures to cool a much larger object to extremely low temperatures.

What's more, the prototype NIST refrigerator, which measures a few inches in outer dimensions, enables researchers to place any suitable object in the zone and later remove and replace it, similar to an all-purpose kitchen refrigerator. The cooling power is the equivalent of a window-mounted air conditioner cooling a building the size of the Lincoln Memorial in Washington, D.C.

"It's one of the most flabbergasting results I've seen," project leader Joel Ullom says. "We used in a to cool a block of copper. The copper is about a million times heavier than the refrigerating elements. This is a rare example of a nano- or microelectromechanical machine that can manipulate the macroscopic world."

The technology may offer a compact, convenient means of chilling advanced sensors below standard —300 milliKelvin (mK), typically achieved by use of —to enhance their performance in systems, telescope cameras, and searches for mysterious dark matter and dark energy.

As described in Applied Physics Letters, the NIST refrigerator's cooling elements, consisting of 48 tiny sandwiches of specific materials, chilled a plate of copper, 2.5 centimeters on a side and 3 millimeters thick, from 290 mK to 256 mK. The cooling process took about 18 hours. NIST researchers expect that minor improvements will enable faster and further cooling to about 100 mK.

The cooling elements are sandwiches of a normal metal, a 1-nanometer-thick insulating layer, and a superconducting metal. When a voltage is applied, the hottest electrons "tunnel" from the normal metal through the insulator to the superconductor. The temperature in the normal metal drops dramatically and drains electronic and vibrational energy from the object being cooled.

NIST researchers previously demonstrated this basic cooling method** but are now able to cool larger objects that can be easily attached and removed. Researchers developed a micromachining process to attach the cooling elements to the copper plate, which is designed to be a stage on which other objects can be attached and cooled. Additional advances include better thermal isolation of the stage, which is suspended by strong, cold-tolerant cords.

Cooling to temperatures below 300 mK currently requires complex, large and costly apparatus. NIST researchers want to build simple, compact alternatives to make it easier to cool NIST's advanced sensors. Researchers plan to boost the cooling power of the prototype refrigerator by adding more and higher-efficiency superconducting junctions and building a more rigid support structure.

Explore further: Study details laser pulse effects on behavior of electrons

More information: (Phys.org) —Lowell, P. et al. Macroscale refrigeration by nanoscale electron transport. Applied Physics Letters. 102, 082601 (2013); Published online 26 Feb. 26, 2013. dx.doi.org/10.1063/1.4793515.

See 2005 NIST Tech Beat article, "Chip-scale Refrigerators Cool Bulk Objects," at www.nist.gov/pml/div686/chip_scale_042105.cfm

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User comments : 18

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EyeNStein
2.1 / 5 (7) Mar 06, 2013
'similar to an all-purpose kitchen refrigerator.'
If you want 100mK beer, and you have a pre-chiller to make your fridge superconduct.
axemaster
5 / 5 (1) Mar 06, 2013
So am I correct in thinking that basically the fridge is like a reverse polarized diode, and the dark current drains off heat?

EDIT: Nvm, it's a bit more complex than that.
El_Nose
5 / 5 (1) Mar 06, 2013
wait it uses a superconductor -- doesn't the superconductor have to be pretty cold in the first place?
SoylentGrin
not rated yet Mar 06, 2013
A few questions...

Does this eliminate the need for coolants? Imagine if we wouldn't need to use helium or nitrogen for cooling anymore...

Where does the heat go? How much power does it draw? If minimal, could you take advantage of the temperature differential between room temperature and the copper block with a Stirling engine of some kind?
SoylentGrin
not rated yet Mar 06, 2013
I've wondered before about "micro cryonics"; have elements that can cool the parts of a circuit or device that need to be cooled, but leave the device itself relatively at room temperature.
Could this be it? Use the principles in this device to control temperature within a circuit like you would control magnetic fields or current at points within the circuit...
hemitite
4 / 5 (1) Mar 06, 2013
"Where does the heat go"
I think that it is superconducted away with the "fast" electrons.
humy
not rated yet Mar 06, 2013
I have 3 questions:

Is that copper platform surrounded by and in direct contact with air? Because that doesn't look like a vacuum chamber in that diagram and surely it would hopelessly ice-up to destruction if it was in direct contact with air at below 1K!

Very roughly, what sort of power consumption are we talking about to power one of these things? KWs? MWs? GWs?

And, like SoylentGrin, along with everyone else who knows anything about the science, I really want to know does this eliminate the need for coolants?
Lurker2358
1 / 5 (3) Mar 06, 2013
it says it cooled from 290mK to 256mK...

So unless that first number's units is a typo, this is only about 34mK worth of cooling.
SoylentGrin
5 / 5 (1) Mar 06, 2013
Using three linked NIS devices, we reduced the temperature of a 1.9 cm3 copper stage from 290 mK to 256 mK with 700 pW of cooling power at 290 mK.

Three devices used 700 picowatts to reduce by 34 millikelvin.
Not quite the huge breakthrough I was thinking. Oh well...
It's still an interesting effect. Guess we won't be doing away with helium cooling for a while, though.
Shabs42
not rated yet Mar 06, 2013
Using three linked NIS devices, we reduced the temperature of a 1.9 cm3 copper stage from 290 mK to 256 mK with 700 pW of cooling power at 290 mK.

Three devices used 700 picowatts to reduce by 34 millikelvin.
Not quite the huge breakthrough I was thinking. Oh well...
It's still an interesting effect. Guess we won't be doing away with helium cooling for a while, though.


But they also say they think they can get it down an additional 156 mK and do it faster. Not going to solve the world's problems, but could still be a huge money saver.
ValeriaT
1 / 5 (3) Mar 06, 2013
So unless that first number's units is a typo, this is only about 34mK worth of cooling.
...during 18 hours in addition. An impressive cooling stuff indeed.
migbasher
3.7 / 5 (3) Mar 06, 2013
Can't wait to slap one of these babies on my new intel... If it makes the journey.
StarGazer2011
1 / 5 (3) Mar 07, 2013
Using three linked NIS devices, we reduced the temperature of a 1.9 cm3 copper stage from 290 mK to 256 mK with 700 pW of cooling power at 290 mK.

Three devices used 700 picowatts to reduce by 34 millikelvin.
Not quite the huge breakthrough I was thinking. Oh well...
It's still an interesting effect. Guess we won't be doing away with helium cooling for a while, though.


Who writes science press releases coz it sure aint scientists! Every result is hailed as a world changing breakthrough, until someone actually does the maths.
Im not disparaging this work; its interesting and useful in a limited lab setting. Kudos to them! But the hype surrounding every little thing makes it easy to become desensitised; I mean according to the press releases you would think there were over unity solar panels and dark matter landfill by now!
WittyNickName
not rated yet Mar 07, 2013
For consumer use, this technology is probably not going to work. At least not in the near future.

But if you look at CERN's (and other) lab's cooling requirements it certainly looks promising. There are issues with the amount of remaining Helium. So perhaps it won't replace Helium cooling completely, but what if it was used as a "last mile" in conjunction with Helium, or perhaps once things are cold enough it takes over. Would it be possible to reduce the amount of gasses required ?

I'm trying to say, not as a complete replacement for current methods but rather in addition to.

I need someone with a bigger brain to think about that.
Soylent_Grin
not rated yet Mar 07, 2013
what if it was used as a "last mile" in conjunction with Helium, or perhaps once things are cold enough it takes over


I think that's exactly the usefulness of this. It's relatively easy (note, relatively) to get down to 300 mK, but removing the last few hundredths of a degree take extraordinary techniques. This can assist, easing the hardest and costliest portion of a trip down the scale.

It also demonstrates a quantum effect that in itself is pretty cool (no pun intended) and may be able to be useful in other ways. It isn't a useless thing at all, and in many ways is worthy of the hype.
We won't be getting away from the need for helium today, unfortunately, but this may point the way.
BSD
1.8 / 5 (5) Mar 09, 2013
We won't be getting away from the need for helium today, unfortunately, but this may point the way.

Unfortunately we are too busy wasting a finite resource blowing up useless balloons.
The possibilities of this type of fridge is endless.
baudrunner
1 / 5 (3) Mar 10, 2013
"I need someone with a bigger brain to think about that."
Okay. Actually, this experiment was probably inspired by the method for getting bosons to the super-cooled state in Bose-Einstein condensate experiments. They use lasers to do that, and this experiment looks to simulate this process almost mechanically. This validates the article, because the results are successful, and it could only lead to bigger and better things.
_traw_at
not rated yet Mar 11, 2013
This looks promising, but I doubt it will end up in production of deep freezes that run off partial watt pv cells.
Too bad. :-(

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