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posted by chromas on Tuesday September 11 2018, @04:20AM   Printer-friendly
from the Nanoscale—so-hot-right-now dept.

Heat transfer surprise could lead to thermal transistors

As much as 100 times more heat than predicted by the standard radiation theory can flow between two nanoscale objects, even at bigger-than-nanoscale distances, researchers at the University of Michigan and the College of William and Mary have reported in the journal Nature. The new results could have implications for better solar cells, materials that behave like one-way valves for heat flow and perhaps even a heat-based computing platform.

Max Planck's theory of radiation, proposed in 1900, set the stage for quantum mechanics and has held up well over the intervening century. But five years ago, a microstructure in the lab of Pramod Reddy, U-M professor of mechanical engineering, was letting an astonishing amount of heat flow between objects that should have been insulated from one another. [...] In an object the size and shape of a credit card, heat would ordinarily radiate from each of the six sides in proportion to the surface area. But the team found that when the structures were extremely thin—at the thinnest, about half the wavelength of green light—those edges released and absorbed much more heat than anticipated.

[...] While the effect is strongest at the microscale and smaller, the emerging field of nanotechnology could mean that we will see this new idea used in devices. "You could potentially control heat in new ways because we have identified the mechanism of heat transfer," Reddy said.

Examples proposed by the team include controlling the flow of heat in a way similar to how electronics manage electrons, making heat transistors for next-generation computers and diodes (like one-way valves). For example, future building materials could let heat out during cool summer nights but keep it in during the winter. Solar cells could harness the portion of the sun's spectrum that isn't converted to electricity for other purposes. A roof installation could send this lost energy to heat water, for instance. Reddy cautions that a heat-based computing device would be slower and larger than an electronic version, but he believes it might be preferable in certain situations, such as high-temperature environments where conventional electronics are damaged.

Hundred-fold enhancement in far-field radiative heat transfer over the blackbody limit (DOI: 10.1038/s41586-018-0480-9) (DX)


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  • (Score: 0) by Anonymous Coward on Tuesday September 11 2018, @05:28AM

    by Anonymous Coward on Tuesday September 11 2018, @05:28AM (#733062)

    Nothing in the way to reflect it back?

  • (Score: 0) by Anonymous Coward on Tuesday September 11 2018, @06:20AM

    by Anonymous Coward on Tuesday September 11 2018, @06:20AM (#733067)

    Wouldnt this be fastest for a gas?

  • (Score: 1, Insightful) by Anonymous Coward on Tuesday September 11 2018, @10:35AM (1 child)

    by Anonymous Coward on Tuesday September 11 2018, @10:35AM (#733098)

    The question neither being asked nor addressed is precisely how is this possible?
    This looks like either a Cold Fusion style result, or new physics.
    Our models, our science, our theories make certain predictions.
    This is reporting 100 fold increase in thermal transfer over what the current laws of physics say is possible.
    We need something to explain this, it's important. It's either real and we have new physics or it's not real and this is a fraud.
    Won't someone please think of the physicists!

    • (Score: 3, Interesting) by urza9814 on Tuesday September 11 2018, @01:28PM

      by urza9814 (3954) on Tuesday September 11 2018, @01:28PM (#733134) Journal

      Yup, my thoughts were similar. And if this is indeed true it seems like a pretty big deal.

      I've been watching a lot of futurism stuff lately, and heat is one of the common limitations -- ie, "We don't know precisely how you'd power a generation ship, nor do we know precisely how one would be built (although we can make some good guesses,) but we can at least determine some values for a possible size and population density based on the amount of heat that human beings produce and how much surface area would be required to dissipate that heat" -- and alternatively "We have this idea for how to build a warp drive, but the amount of energy required would probably produce so much heat that anyone or anything inside would be vaporized."

      I get the impression that heat is a pretty big limiting factor in both current (PCs, obviously) and future tech...and here's some researchers who seem to be implying that we don't have a clue how heat actually works yet? That sounds like fantastic news, but also too good to be true which means I'm likely missing some critical details here...

  • (Score: 2) by Gaaark on Tuesday September 11 2018, @11:09AM

    by Gaaark (41) Subscriber Badge on Tuesday September 11 2018, @11:09AM (#733107) Journal

    "As much as 100 times more heat than predicted by the standard radiation theory can flow between two nanoscale objects, even at bigger-than-nanoscale distances,"

    I could have told you that: when making out you get to see more skin because
    "I'm taking off my shirt: man it's hot in here"
    Response: "Me too!"

    Result? Boobage!

    ;)

    --
    --- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
  • (Score: 3, Interesting) by shortscreen on Tuesday September 11 2018, @06:30PM (1 child)

    by shortscreen (2252) on Tuesday September 11 2018, @06:30PM (#733237) Journal

    Now we just need a heatsink with nanoscale cooling fins. Although I wonder if the internal heat conductivity of these things is any good, and how tightly they can be packed together before they effectively become one macro object rather than an array of nanoscale ones.

    • (Score: 0) by Anonymous Coward on Tuesday September 11 2018, @07:16PM

      by Anonymous Coward on Tuesday September 11 2018, @07:16PM (#733257)

      And don't touch it during assembly: a nanoscale papercut would suck!

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