Introducing the Quantum Refrigerator – the coolest cool tech

Since Willis just published an essay on refrigeration systems and how the Earth has its own version, I thought this story might be fun and educational. Many people don’t know that Albert Einstein invented a refrigerator system in 1926 after he became world famous for his Theory of Relativity that was proven by solar eclipse measurements in 1922. I mean, after that what do you do for an encore? Build a fridge I guess.

About the same time, Einstein also became the most prominent critic of Quantum Theory which he had helped to create decades earlier. Given that, I think he’d find the idea of a Quantum refrigerator both hilarious and intriguing at the same time. – Anthony

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.

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. Credit: Schmidt/NIST

What’s more, the prototype NIST refrigerator, which measures a few inches in outer dimensions, enables researchers to place any suitable object in the cooling 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 quantum mechanics in a nanostructure 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 cryogenic temperatures—300 milliKelvin (mK), typically achieved by use of liquid helium—to enhance their performance in quantum information 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.

This work is supported by the National Aeronautics and Space Administration.

###

* P.J. Lowell, G.C. O’Neil, J.M. Underwood and J.N. Ullom. Macroscale refrigeration by nanoscale electron transport. Applied Physics Letters. 102, 082601 (2013); Published online 26 Feb. 26, 2013. http://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.
About these ads

60 thoughts on “Introducing the Quantum Refrigerator – the coolest cool tech

  1. You use the fridge the cool the superconductors … you use the superconductors to supply power to the fridge … and you run the rest of your installation – say a magnetically-driven ships engine – using the superconducting material …

    Sounds a bit perpetual motion, but I’m talking about a shift in efficiency, not magic. Would seem to offer a route that makes use of presently known low temp superconductors, since ambient temp superconductors seem to be … difficult.

  2. How much power is required? i.e., if there was a window-sized unit, how much power would it take to cool a building the size of the Lincoln Memorial, and how much power would conventional AC units use?

  3. I had no idea that electrons even had a temperature until I read about “the hottest electrons”.

    What exactly does the temperature of an electron mean?

  4. I like the way they refer to 300mK as “standard” cryogenic. Getting down to 300mK takes some serious engineering.

    Going down from 290mK to 256mK doesn’t sound like a lot, but . . .

    Well, I can’t complete that sentence. It would be interesting to read an explanation of the reasons why this would make a difference. And what happens at 100mK? 50mK? What new frontiers of science would be opened? Enquiring minds want to know.

  5. Just to be clear: Einstein did not win a Nobel for the Theory of Relativity. As the Nobel.org site states

    The Nobel Prize in Physics 1921 was awarded to Albert Einstein “for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect.”

    Albert Einstein received his Nobel Prize one year later, in 1922. During the selection process in 1921, the Nobel Committee for Physics decided that none of the year’s nominations met the criteria as outlined in the will of Alfred Nobel. According to the Nobel Foundation’s statutes, the Nobel Prize can in such a case be reserved until the following year, and this statute was then applied. Albert Einstein therefore received his Nobel Prize for 1921 one year later, in 1922.

    http://www.nobelprize.org/nobel_prizes/physics/laureates/1921/

    What happened was that in 1921, the Nobel Committee announced that it was going to award Einstein a Nobel for the Theory of Relativity. There was such an uproar from reputable scientists and institutions in Europe calling it false and accusing Einstein of plagiarism that the Nobel Foundation was forced to recall the reason for the prize, and find something else to give him a prize for; hence, his “services to Theoretical Physics” and the “law of the photoelectric effect.”

    The Times of London has the detail in its archives—it’s voluminous over the year—but it’s behind a paywall now. The American press ignored it, so we still believe it, and I guess the worker bees at Wikipedia are hard at work promoting the myth.

  6. That is “cool”. Too bad it looks like it still needs a cryogenic fluid to get the article down to the initial temperature. I was hoping it would be a way to cool laboratory sensors from room temp. Cryogenics are still quite expensive, but this should help get things even colder and make it less costly to keep things cryogenic. Decreasing thermal noise is always a good thing.

  7. We live in Science Fiction.

    I wonder how long it’ll take to scale this into a replacement for the household refrigerator. Would it reduce costs? Is it even feasible? Ooooooooh forget that, I want one to use as a heatsink on my computer!

  8. Of course the theory of Relativity was not ‘proven’ by any measurements – it was supported, or rather, not falsified. We sceptics should be careful with our language (and our science) if we have any chance to rebuild it after the strains put upon it by the warmistas!

  9. “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.
    …1″ copper plate… from 290 mK to 256 mK. The cooling process took about 18 hours. ”

    8 hours to loose 44 thousandths of a degree ?

    Comparison does not seem to add up , unless you’re saying cooling the building on a time-scale like since the Holocene maximum.

    Maybe the comparison is not explained too well. :?

  10. As soon as I saw this I thought of the MEMS technology I was recently reading about – MicroElectroMechanical Systems… and sure enough, one of the applications listed includes “heat exchangers”.

    MEMS will often employ microscopic analogs of common mechanical parts and tools; they can have channels, holes, cantilevers, membranes, cavities, and other structures. However, MEMS parts are not machined. Instead, they are created using micro-fabrication technology similar to batch processing for integrated circuits.

    As soon as a new technology exists, someone runs along with a breakthrough using it. We do live in interesting times.

    Then again… 100mK would be an interesting achievement. Isn’t anyone worried about reaching absolute zero and instantly freezing the entire planet anymore? I remember when that one was going around…

  11. Check out Frank Znidarsic’s mathematically-sound method of using only Newtonian and Hamiltonian equations to directly calculate Planck’s constant, starting with this YouTube series:

    Something so simple even High School students can understand–oh wait, the narrator IS a high school student!

    (Warning–the formulation was obtained based on quantified results from cold fusion and anti-gravity experiments, so if you aren’t willing to considering those phenomena as possible, you probably won’t be open-minded enough to accept the rest, regardless of the robust mathematical simplicity.)

  12. That’s really cool! (Pun intended. LOL)

    From the earliest days of the microwave oven, I always wanted to be able to cool or freeze things with equal speed and ease. Maybe someday a “microwave” will include both functions. :)

  13. This post is just another reason to keep on turning to this site for interesting news about scientific discoveries. Thanks.

  14. This reminds me of Maxwell’s Demon. The demon was dreamed up by Maxwell as a way to violate the 2nd law of thermodynamics. It sits at a small opening between 2 identical chambers of gas, and allows only the fastest-moving molecules to pass one way through the opening. This has the effect of heating up and increasing the pressure in one chamber, while the other cools down and loses pressure, thereby violating the 2nd law. Apparently it can be shown that in order to perform this simple task, the Demon himself gains entropy, and the 2nd law is safe!

  15. I don’t recall that Eddington’s eclipse measurements were precise enough to really confirm general relativity. Galactic gravitational lensing has done that big time, though.

  16. Richard Barraclough,
    “Apparently it can be shown that in order to perform this simple task, the Demon himself gains entropy, and the 2nd law is safe!”

    Interesting. I wonder if God gained entropy too, when He created the universe.

  17. ActonGuy says:
    March 12, 2013 at 4:42 am
    How much power is required? i.e., if there was a window-sized unit, how much power would it take to cool a building the size of the Lincoln Memorial, and how much power would conventional AC units use?
    =========================================================
    The important questions are:
    What’s its carbon footprint
    and how many solar panels / windtowers will it take to power it

  18. Ian E says:
    March 12, 2013 at 5:56 am
    Of course the theory of Relativity was not ‘proven’ by any measurements – it was supported, or rather, not falsified. We sceptics should be careful with our language (and our science) if we have any chance to rebuild it after the strains put upon it by the warmistas!

    I understand being careful in language, but the theory of general relativity has been “proven” to be quite useful in improving GPS accuracy and many other things we take for granted daily. In the future we may find, that like Newton before him, he only described a special case of a yet larger whole, but it will probably be a while before science reaches the level of precision required to notice any aspects of that larger whole that show the theory to be incomplete.

    I understand that an experiment can only do one of three things: repudiate a theory by showing a counter example in a case in which it should apply; be inconclusive due to error bars larger than the effect being measured or other experimental problem; or support the theory by measuring something uniquely predicted by it.

    We tend to accept a theory when hundreds and thousands of experiments find the predicted outcome, but we no longer like to call new ideas “laws” like they did in the 17th-19th centuries. Thus we have Newton’s Law of Gravity which isn’t really a law as we have shown it to be incomplete. We have Ohm’s law, which works where it applies, but has a little problem at the micro scales of quantum tunneling semiconductors. In fact most of the classical “laws” have little hitches when we attempt to apply them to extremely small or extremely large phenomena, but work just great in their traditional domains. I wouldn’t do electronics any more if I had to solve quantum statistics for every calculation to get circuits to work properly (which probably is necessary for extreme precision circuits).

  19. What this does for us is it saves our helium reserves, if it can be scaled enough to be used in all universities. Compressing helium into a liquid state is currently the only viable method for achieving such temperatures.

  20. “I understand that an experiment can only do one of three things: repudiate a theory by showing a counter example in a case in which it should apply; be inconclusive due to error bars larger than the effect being measured or other experimental problem; or support the theory by measuring something uniquely predicted by it.”

    and dont forget the 4th. Appear to support the theory, where the happy consequence of bad measurement and bad theory work together. Oh and the 5th, an experiment can suggest that a theory is incomplete and additional hypotheses are needed to explain the result. oh and the 6th, appear to repudiate the theory, but actually point to bad data collection.

    And of course, nothing in the experimental result tells you what to do next.

    [Reply: 7th… PROFIT!! ~mod]

  21. policycritic

    In what way are “… I guess the worker bees at Wikipedia are hard at work promoting the myth” that Einstein won a Nobel for the Theory of Relativity?

  22. RockyRoad says March 12, 2013 at 6:13 am

    (Warning–the formulation was obtained based on quantified results from cold fusion and anti-gravity experiments, so if you aren’t willing to considering those phenomena as possible, you probably won’t be open-minded enough to accept the rest, regardless of the robust mathematical simplicity.)

    Maybe there are those that would like a ‘crash course’ to allow them to ‘come up to speed’ on where CF A/K/A LENR stands today … this 101-level ‘survey’ course (“IAP short course”) given at MIT in a series of 12 videos by Dr. Peter Hagelstein in January of this year (2013) may just fill that bill:

    ** Notice the warning issued in the beginning: “Working in this field can destroy your career .. this is a very dangerous field to be associated with” **

    #1 Cold Fusion 101 Dr. Peter Hagelstein at MIT 01/22/2013 (Day 1 Part 1)

    (Note the tongue-in-cheek ref to Wikipedia in 1 above)

    #2 Cold Fusion 101 Dr. Peter Hagelstein at MIT 01/22/2013 (Day 1 Part 2)

    .
    And so on …

    .

  23. What exactly does the temperature of an electron mean?

    In any material, the electrons are typically in thermal equilibrium with the material itself. Electrons are fermions, and practically speaking this means that they have a distribution of energies around the so called “Fermi Energy”, the energy of the Fermi Surface where all of the electrons are packed into their ground states subject to the Pauli Exclusion Principle. Without going into the details of electronic band structure, this surface exists in a reciprocal “momentum” like space consisting of the wave-numbers of the electrons in various directions in the lattice.

    At finite temperature some of the electrons near the fermi surface are kicked out of their ground state and into the bands of states just above that surface. They leave behind “holes” in the bands of states just below that surface. This, along with whether or not the fermi surface occurs inside a band or in the gaps in between bands, determines things like the conductor/insulator properties of materials. Superconductivity is also closely related to this sort of fermi surface structure, although it is a purely quantum phenomenon that I won’t go into here.

    The electrons in the bands above the fermi surface at finite temperature have an energy ABOVE the ground state energy, and hence one can, to the extent that there are enough of them in a slice of a band for thermal averaging to make sense, associate a temperature with their energy using e.g. k_B T = E (where k_B is Boltzmann’s constant, and where the relationship probably isn’t strictly linear). “Hotter” electrons are in basically found in bands with higher energies farther above the fermi surface for the material.

    So what the nanoscale cooling elements do is basically create a way for these “hotter” higher energy electrons to be differentially removed from a material along with an applied current. As they are removed, they are replenished with “cooler” lower energy electrons (the material remains electrically neutral). However, they quickly equilibrate with the temperature of the material lattice — the “phonon” temperature associated with the microscopic oscillations of the actual massive atoms that make up the substance. In the process the electrons absorb energy from the lattice, dropping its enthalpy content and hence its temperature. These hotter electrons are then removed, in a more or less continuous cycle as long as current is applied.

    This is a crude picture, but should be enough to answer your question — “hotter” electrons are ones that on average have energies farther above the fermi surface for the material, even though individual electrons have no temperature, only energy, and perhaps the secondary description will give insight into how the cooling takes place.

    This article might also help, as Peltier coolers have been around for a long time and are functionally quite similar:

    http://en.wikipedia.org/wiki/Thermoelectric_cooling

    Their basis isn’t exactly the same, as it is more classical, but the IDEA of differentially moving electrons at a higher temperature to obtain cooling is very much the same.

    rgb

  24. Jeremy says:
    March 12, 2013 at 7:53 am
    What this does for us is it saves our helium reserves, if it can be scaled enough to be used in all universities. Compressing helium into a liquid state is currently the only viable method for achieving such temperatures.

    This is one of the reasons why I support nuclear power! Collect all those alpha particles after they have spent the majority of their kinetic energy, add electrons and poof instant Helium. (or do they only do this in research reactors?)

  25. Good to see them getting some publicity over at NIST. Those guys have been doing some good work for a while.

    This is not something you scale into a common refrigerator. This is for taking things that are really cold and making them really really cold. In general, you just can’t have quantum effects at high temperatures because all the particles involved are switching states way too frequently to allow any effect. That’s why room temperature superconductivity is likely impossible.

    Why this is a big deal, and what applications they are used for: the biggest application they have in mind are very low temperature detectors of light from gamma rays all the way through millimeter waves, things like bolometers. The fundamental limit for sensitivity is how cold you can make your detectors. If you can make them really cold for really cheap, then you solve a lot of problems. This has applications for putting arrays of detectors into cameras, acting sort of like ultra-sensitive CCDs that work at all kinds of weird wavelengths. I think the biggest application is in astronomy, but there’s a lot more out there, including dark matter searches, radioactive isotope testing, and even passive security applications (i.e. tell if someone has a knife without bombarding them with x-rays). Before the only way to get colder than 250 or so mK was to use a dilution refrigerator (where you take advantage of the fact that 4He and 3He like to mix together at a certain ratio to cool things to ~10 mK) or an adiabatic demagnetization refrigerator, which is tricky, tempermental and has very low cooling power. If this can be done cheaply and easily, a lot of these applications get a lot easier.

    As for the shortage of helium: most instruments no longer just boil off liquid helium (most, not all). Most use pulse tube coolers to get to LHe temperatures, then have closed cycle refrigerators to go lower, so you’re not actually losing helium. The trouble is, compressing 4He can only get you down to 0.8K or so, which is still way too hot for most applications. You need 3He, which is not found naturally, to get down to the ~300mK temperatures even to start. 3He is a byproduct of making nuclear weapons, as I understand it, so it will only get more scarce for us.

  26. “… 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.”

    Wait….something bothers me.

    Does 290mK to 256mK mean From 290 milli-Kelvin to 256 milli-Kelvin, in 18 hours?

    In that case, do you realise how cold 290 milli-Kelvin already is, before starting? It is 0.29 Kelvin above the absolute zero point!!!

    And from 290 milli-Kelvin to 256 milli-Kelvin is only 0.034 Kelvin difference…….and it tool 18 hours…

    So, what bothers me is; How long would it take to cool something down from 272.29 Kelvin to 272.256 Kelvin? 18 hours too?

  27. I think their could be a market for “quantum can coolies” or on a larger scale “Earth cooling superconducting quantum global warming balancer” . If we could just get the gang to tell us what the perfect temp should be where we won’t have hurricanes, droughts, tornados and such. We could just set the thermostat to the right temp. /sarcasm

  28. Any comments on the efficiency of the cooling unit? Low cost, high efficiency cooling to cryonic temperatures would have some interesting applications. (for example using LN2 as a way to store “cold” for load leveling summer cooling demands, you can recover meaningful energy from the expansion as well)

  29. RockyRoad says March 12, 2013 at 6:13 am

    Check out Frank Znidarsic’s mathematically-sound method of using only Newtonian and Hamiltonian equations to directly calculate Planck’s constant, starting with this YouTube series:


    Killer series there Rocky … although some (make that: “many” over 30; the artist/producer of that work states his “… purpose is to reach those under 30″) aren’t going to be able to ‘stomach’ the sound/music track … to that end I recommend maybe simply jumping-ahead to Pt. 5 in the series (a little more theory w/experimental results, demos tossed in):

    Part 5

    BTW, the series doesn’t claim to get mathy until #12 (or so) in the series.

    .

  30. Steve C says March 12, 2013 at 11:35 am

    http://www.symmetricom.com/products/frequency-references/chip-scale-atomic-clock-csac/SA.45s-CSAC/

    Oh, God. Where’s the back of the queue of amateurs trying for a complementary sample?

    Hobbyists have never had it so good … maybe too late for ‘samples’ (when everyone is asking for one!) but easily available via CC debit:

    https://www.sparkfun.com/pages/GPS_Guide.

    Note the optional update-rates on some of those exceed 10 Hz (10 position updates per second!)

    .

  31. Cooling the mass using just the “thermal mass” of the electrons is where the room air conditioner analogy arises. Having played with the Josephson Effect, I can appreciate the excitement that this creates. There’s nothing like having a macro response to a atomic event to get the blood flowing!

  32. So with this fridge, if I know my beer is cold, I can’t know where it is, and if I know where it is, I can’t know it’s cold?

    What happens when I open the fridge?

  33. How is this different than a thermoelectric cooler that are available commercially from Igloo that works faster than 18 hours?

  34. RoHa says:
    March 12, 2013 at 4:55 pm
    So with this fridge, if I know my beer is cold, I can’t know where it is, and if I know where it is, I can’t know it’s cold?

    What happens when I open the fridge?

    The cat dies?

  35. Einstein may have invented a type of refrigeration system, but the Biltmore House in Asheville, NC was originally built with a refrigerator. In 1895….

  36. Owen in GA says:
    March 12, 2013 at 6:40 pm

    RoHa says:
    March 12, 2013 at 4:55 pm
    So with this fridge, if I know my beer is cold, I can’t know where it is, and if I know where it is, I can’t know it’s cold?

    What happens when I open the fridge?

    The cat dies?
    ===

    Very sharp ;)

    I still don’t get Lincoln memororial bit. Seems like someone is confusing mW and MW !

  37. RoHa says:
    March 12, 2013 at 4:55 pm

    So with this fridge, if I know my beer is cold, I can’t know where it is, and if I know where it is, I can’t know it’s cold?

    What happens when I open the fridge?
    ———————————————————————————————————-
    You may ask Schroedinger’s cat in the fridge for answers – no, wait…

  38. The refrigerator Einstein was interested in was the Munters/Von Platen constant pressure ammonia adsorbtion system the rights of which were bought by Electrolux who marketed it in the USA under the Demotic trademark who I believe still make them today. Because it has no moving parts and is powered by heat it made domestic refrigeration accessible where there was no electricity because it could use a paraffin [kerosene] flame, today bottled gas is used and often an alternate/auxiliary electric heater is fitted as well. They are used by campers, caravanners, and I imagine in the USA in backwoods sports cabins and the like.

    When I found out how they worked at about age twelve I was fascinated, such an elegant application of the law of partial pressures. I did not know back then Mr. Einstein had been interested by the cycle.

    Their drawback of course is the very poor efficiency, for domestic use a COP of about a third is the best that can be got.

    Even so i still have the one my grandparents bought in 1931 and it still works fine. I keep it in the garden shed I laughingly call my office cum lab where it keeps the place warm and the milk and white wine, for use when inspiration flags, cool. It has never been serviced in its life, beyond twiddling the thermostat when it gets a bit sticky: it just keeps soldiering going on and on.

    Kindest Regards

  39. Owen in GA says:
    March 12, 2013 at 9:44 am
    “This is one of the reasons why I support nuclear power! Collect all those alpha particles after they have spent the majority of their kinetic energy, add electrons and poof instant Helium. (or do they only do this in research reactors?)”

    There’s Helium that gets created this way in all natgas wells, it’s just only collected in a few places around the globe where Helium content is particularly high, because that suffices to satisfy the demand.
    The market is so boring that I don’t even find it on the stock markets. Prices have not even doubled since 1998; looks like ordinary inflation to me (notice the acceleration since QE1). (Yes I know the CPI says there is no inflation but do you believe that.)

    http://www.nordic-oil.de/?id=213

Comments are closed.