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Power

Researchers Build Device That Turns Heat Into Light, Possibly Boosting Solar Cell Efficiency (pv-magazine.com) 124

Posted by EditorDavid from the hot-ideas dept.
Kant (Slashdot reader #67,320) shared this story from the photovoltaics news site PV Magazine: Scientists at Rice University in Texas have developed a device which converts heat into light by squeezing it into a smaller bandgap. The 'hyperbolic thermal emitter' could be combined with a PV system to convert energy otherwise wasted as heat -- a development the researchers say could drastically increase efficiency...

"Any hot surface emits light as thermal radiation," said Gururaj Naik, assistant professor of electrical and computer engineering at Rice. "The problem is that thermal radiation is broadband while the conversion of light to electricity is efficient only if the emission is in a narrow band." The team worked to create a device that could squeeze the photons emitted as heat into a narrower band that could be absorbed by a solar cell...

The next step for the research will be to combine the 'hyperbolic thermal emitter' device with a solar cell. "By squeezing all the wasted thermal energy into a small spectral region we can turn it into electricity very efficiently," said Naik, "the theoretical prediction is that we can get 80% efficiency."
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Researchers Build Device That Turns Heat Into Light, Possibly Boosting Solar Cell Efficiency More

Researchers Build Device That Turns Heat Into Light, Possibly Boosting Solar Cell Efficiency

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  • Boy who cried wolf (Score:4, Interesting)

    by nonBORG ( 5254161 ) on Sunday August 04, 2019 @05:39PM (#59039406)
    All these things are pretty exciting but just like the 500 new battery technologies that create battery cells with 1/10 the cost and 10x the storage we get tired of hearing about them due to the fact that we have been hearing about them so much without actually seeing it happening. Wish they would commercialize some of these ideas and so we could use them. My solar powered EV and home is just another c years away. (unfortunately c seems to stay constant)
    • I often wonder myself.
      Is it possible that no VC money is interested in being the Pathfinders?
      You do know how you recognize pathfinders?
      They're the guys with arrows sticking out of their butts

      • In the real world it can take years, decades even, for certain very small percentage of promising lab tech to become product. Most things don't make it for a number of reason including cost, scalability, experimental errors, superior methods found, etc.. This is normal. Life is not like an episode of Star Trek where amazing new thing conceived and built in hour episode less commercials.

    • Re:Boy who cried wolf (Score:5, Insightful)

      by ljw1004 ( 764174 ) on Sunday August 04, 2019 @06:05PM (#59039508)

      we get tired of hearing about them due to the fact that we have been hearing about them so much without actually seeing it happening.

      If you get tired of reading tech-related research, why are you on slashdot?

      (I don't get tired. I love reading all these stories)

      • If you get tired of reading tech-related research, why are you on slashdot?

        What is tiring is reading about technology that never becomes reality. What is tiring is reading about this technology in triplicate after it apparently didn't get enough investors the first time it was put up in an article somewhere. It's real easy to promise and not deliver. When they deliver then I'd love to read about how it works.

        • What is tiring is reading about technology that never becomes reality.

          https://youtu.be/gldldoyROhs [youtu.be]

        • What is tiring is reading about technology that never becomes reality.

          Many areas of technology, including solar cells and thermal energy scavanging, have dramatically improved over the last decade, mostly because of the very research that you erroneously believe "never becomes reality".

          • Many areas of technology, including solar cells and thermal energy scavanging, have dramatically improved over the last decade, mostly because of the very research that you erroneously believe "never becomes reality".

            As someone that worked on a solar car project at university I am quite aware of which technologies have become reality and that this is because of plenty of research. I am also aware that there are plenty of technologies that have not yet, and likely will not ever, become reality.

            What we have here is a technology that promises to increase the efficiency of solar PV cells, which are already reaching theoretical limits. The article is written so poorly that it's difficult to interpret just how much this tec

            • What we have here is a technology that promises to increase the efficiency of solar PV cells, which are already reaching theoretical limits. The article is written so poorly that it's difficult to interpret just how much this technology is supposed to improve solar PV efficiency, and there was no real mention of the cost.

              To be fair, hardly any research spends a lot of time on the economics of a new technology. First you have to figure out if something actually works. THEN you figure out if the economics of it make any sense. There are lots of technologies that technically work but the cost/benefit doesn't make economic sense. No idea in this particular case but one has to try to find out.

              On the other hand I read about successful nuclear power projects overseas and then hearing my own government tell me that it's not economical. Maybe it would be economical if the government issued a license for once

              Define "successful". It's quite plausible that a technology isn't economical in the US where it might be elsewhere. Passenger rail i

              • B) Nuclear plants are low carbon but they have other problems that nobody has solved. (waste, weapons, failure modes)

                They have been solved.
                http://cmo-ripu.blogspot.com/2... [blogspot.com]

                D) Nobody with a brain is saying nuclear will cure all the problems but it damn sure is an important piece of the puzzle.

                No, I'm quite sure that there are many Democrats that claim we can solve the world's energy problems without nuclear power. There is no mention of nuclear power in the Democrat Party platform document, and all the Democrats running for the party nomination for POTUS have said that they will not support nuclear power.

                Oh, wait, you said "with a brain". In that case I agree.

                There are no Democrats in office that have a brain, because if they did then the

            • Did you learn from Fukushima Dai-Ichi?
              Nuke power costs always exceed lifetime projected costs and those are always paid by the Public, not the shareholders

            • On the other hand I read about successful nuclear power projects overseas

              Name one, that was completed on time and under budget, with no government bailouts or underwriting.

        • What is tiring is reading about technology that never becomes reality.

          What are you babbling about? "Never becomes reality"? Pull that smartphone out of your pocket and take a hard look at it. When I was a child the closest thing we had to that was a fictional communications device on freaking Star Trek. It was science fiction. My first computer had 16 KILOBYTES of RAM. You live in a technological paradise that many of us could barely imagine just 40 years ago and you're bitching about technology not becoming reality? Get some perspective.

          I have no idea if this specific

    • It relies upon carbon nanotubes (currently unobtanium in any quantity greater than a gram or two - and even then, more expensive than gold) and running at 700 deg C (which has its own set of issues with the rest of the materials around the cells and connections to them). It's like a spherical cow solution [wikipedia.org].

    • we have been hearing about them so much without actually seeing it happening

      What the fuck are you babbling about; were you born yesterday?? Solar panels now seem to cover half the buildings up here in the Colorado mountains - an impossibility if efficiencies hadn't come a long fucking way - and thanks to advances in motor/generator tech, you can buy an electric supercar that thrashes gas-powered cars costing far more.

      Change has come, and will continue to do so.

    • battery efficiency and capacity has been increasing, as has solar cell efficiency.

      Young people think things are invented and on the market next week, the real world is very different. Years or even decades can be needed to perfect a tech. When was the first solid state electronic device invented? Hint, in late 19th century. When was the first fax sent? Hint, in mid 19th century. When was the first microwave transmitter invented? Hint, 19th century

    • Re: (Score:2)

      by Bengie ( 1121981 )

      just like the 500 new battery technologies that create battery cells with 1/10 the cost and 10x the storage

      Li-ion batteries are about 1/7th the price from 8 years ago but only doubled energy density. Though recently a company said they are starting tooling for mass production of a li-ion battery that will be 1/2 the cost and 4x the energy density.

    • unfortunately c seems to stay constant

      Yup, just under 300 000 km/sec.

  • Dupe (Score:4, Informative)

    by apoc.famine ( 621563 ) <apoc DOT famine AT gmail DOT com> on Sunday August 04, 2019 @05:52PM (#59039452) Journal

    Dupe, and an older one too. I think this was from a few months back.

  • That scheme seems to violate thermodynamics's second principle. Is there anything on that point?

    • I think the idea is that you ca make a material whose emissivity varies with wavelength. (actually of course you can, that is true of any material that has color). So If you have high emissivity at one wavelength, and low at others, thermal emission will happen mostly at that wavelength.

      That makes it easier for practical solar cells to convert the light to electrical power, but presumably doesn't break carnot efficiency. (doesn't change the theoretical conversion efficiency).

      • I think the idea is that you ca make a material whose emissivity varies with wavelength. (actually of course you can, that is true of any material that has color). So If you have high emissivity at one wavelength, and low at others, thermal emission will happen mostly at that wavelength.

        That makes it easier for practical solar cells to convert the light to electrical power, but presumably doesn't break carnot efficiency. (doesn't change the theoretical conversion efficiency).

        The way I read it is that a significant portion of heat in the infra red can have the wave length shortened in the same way that a radio wave can when it bounces in a magnetic field. In theory we could take the energy from any fire and convert with infra red modulation directly to electricity. A boon for cheap gadgets that do stupid things run an led light or radio from the infra red created by a simple campfire. If you can create electricity directly from the radiation of a fire, then the potential is mind

      • The carnot principle/efficiency is only valid for classical heat engines.

    • Re:Thermodynamics's second principle (Score:5, Informative)

      by iggymanz ( 596061 ) on Sunday August 04, 2019 @10:39PM (#59040432)

      No energy is created out of nowhere, instead 2 infrared photons are converted to one visible one. "triplet fusion upconversion" is the process for this article.

      https://en.wikipedia.org/wiki/... [wikipedia.org]

    • If you could take a lot of energy in the form of heat and convert it to less energy in the form of visible-spectrum light, I think you are OK. This conversion is still restricted by 2nd-law considerations, much as a "heat pump" that uses heat flowing from hot to cold in a heat engine to power the transfer of heat from cold to hot in the reverse of a heat engine.

      I once saw in my undergrad Electric Properties of Materials class something about the 2nd-Law interpretation of how a solar cell works. The hea

    • Please explain why it would violate a law of thermo dynamics, and farm in your PhD.

      • It's taking in lower energy photons and spitting out higher energy photons, not hard to see why many would ask if everything is kosher according to laws of thermodynamics. It is of course, photon upconversion is a thing, but to understand how it really works you just might need that PhD and I don't have one. Summary is that it takes several low energy photons to emit one high energy photon though the details of how exactly escape me.

        • The first mistake is to even think that the laws of thermodynamics apply for a system that has nothing to do with thermodynamics.
          Secondly it is pretty simple, two photons with energy x get captured, a photon with energy x + x gets emitted.

          In this thread somewhere is a wikipedia link which explains it pretty good.

          Hint: thermodynamics describes steam engines and fridges ... where hot gases are involved. No hot gas, no law of thermodynamics. Wow, that was so simple again.

          • No hot gas, no law of thermodynamics. Wow, that was so simple again.

            And also totally false. The laws of thermodynamics apply to everything in the universe. They're some of the most fundamental laws out there. The definition of entropy has nothing to do with steam engines or hot gases. For example, https://doi.org/10.1016/j.ijen... [doi.org] analyzes the entropy associated with individual photons.

            • No they don't.

              Applying them to something else are usually fun calculations and not science.

              TLOTD got invented/formulated/discovered for one thing only: describing machines based on heat.

              Everything else in the universe is described by its own subset of physics. E.g. mechanics, relativity theory, quantum theory.

              E.g. there is a pool billiard table, please tell us which law of TLOTD applies to anything that happens in playing pool?

              • Everything else in the universe is described by its own subset of physics.E.g. mechanics, relativity theory, quantum theory.

                These are all fundamental laws that apply to everything in the universe, although to a greatly differing degree.

                there is a pool billiard table, please tell us which law of TLOTD applies to anything that happens in playing pool?

                One pool ball strikes another.
                This causes the molecules in the struck ball to become agitated, raising the temperature.
                The ball radiates this energy away in the form of infra-red photons.
                Do you care? No, but physics has nothing to do with what you do or do not care about.

          • Hot gasses is how thermodynamics was figured out initially, that is not to the same thing as saying hot gasses is the limit to what laws of thermodynamics apply, far from it. They are some of the most fundamental and universal laws of physics known to man, with no known or even suspected exceptions anywhere.

            And your explanation of two photons of energy x resulting in one photon of energy 2x is flat out wrong and also impossible because that really would violate second law of thermodynamics. There will be a

            • And your explanation of two photons of energy x resulting in one photon of energy 2x is flat out wrong and also impossible because that really would violate second law of thermodynamics.
              No, it is not wrong.
              And if you think it would violate a law of thermodynamics, if it was wrong, point out which one. Explain why. And farm in your Nobel Prize.

              Your link was close, the correct link is this one: https://en.m.wikipedia.org/wik... [wikipedia.org]

              • So if no laws of physics are broken you can take room temperature thermal radiation, upconvert it several times to short wavelength which you can drive your solar panel with? So you can build an unpowered air conditioner and infinite power generator all in one which you can use to power a conventional air conditioner as cherry on top? No, just no, that would be a perpetum mobile of the second kind and therefore forbidden by the second law of thermodynamics.

                The explanation here is very simple, you just don'

                • Do energies of two photons of 980nm sum up to energy of one 600nm photon? No, it sums up to more, but some is lost as heat.
                  Hae?
                  You have no clue. So why post?
                  Heat is: photons ...

                  No idea what the other gibberish is about.

                  You obviously have no clue about physics.

                  For laymen: the laws of thermodynamics are super simple. As soon as any kind of energy is converted to heat, it is "difficult - close to impossible" to convert it back into any other form of energy. And thats it. Theromodynamics, thermo meaning heat, h

                  • The point was that you can't take two photons of energy x and sum them up to one photon of energy 2x, x + x = 2x doesn't work here, it's the wrong model to how upconversion works. 980nm photon has energy of 1.265eV, if you take two of them and upconvert them you don't get an photon with energy 2*1.265eV, you get one with energy of 2.066eV at 600nm.

                    But yes, once energy is converted to heat you can't willy nilly convert it back to useful work. But higher energy photons can be converted to work more easily, a

  • Can this technology be applied to Slashdot discussions?

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