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Thread: 230% Efficient LEDs

  1. #1

    Default Re: 230% Efficient LEDs

    Quote Originally Posted by AnAppleSnail View Post
    Please read my post which attempts to explain what is happening in a way people without expertise in quantum physics can understand.
    If you mean the post right above in this thread, then yes I read it since it's right above in this thread.

    Thermal energy can be converted to photons, as can lattice vibrations.
    Which is what the hot metal stick example was exemplifying.

    ...

    edit: now why is this post suddenly listed at top of thread? O_o .... editing post to hopefully "fix" that.
    Last edited by pretmetled; 03-13-2012 at 10:23 AM. Reason: omgwtfbbq top of thread?

  2. #2
    Flashaholic* Mattaus's Avatar
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    Default 230% Efficient LEDs

    ***Apologies if this does not belong in this section of the forums, or if this is repeated news. I searched and could not find it posted previously.***

    So some interesting news taken from Gizmodo but I saw it elsewhere yesterday:

    Light bulbs have always required more electricity than they need to produce light because the energy conversion process — changing electricity to light — was inefficient. But an MIT research team has just shown that an LED can actually give off more light than it consumes in electricity.
    Incandescent bulbs are the poster child of inefficient energy conversion. The devices heated a filament with an electrical current which not only produced light, but a lot of waste heat as well. Fluorescent bulbs, CFLs and even conventional LEDs all generate the same waste heat to varying (albeit much smaller) degrees but none has ever reached 100 per cent efficiency — a mark known as “unity efficiency”.


    The team from MIT posited that while the bulbs energy requirements decrease at an exponential rate (halving the voltage reduces the input power by a factor of four), the lumen output would decrease linearly (halve the voltage and the lumens drop by half as well). This means that at some point, the amount of lumens the bulb is emitting would be more than the amount of energy spent — essentially “free” light.


    Granted, this point occurs only when using minuscule amounts of electricity to power incredibly dim bulbs. In their experiments, the team was able to generate 69 picowatts of light from just 30 picowatts of energy. They did so by harnessing waste heat, which is caused by vibrations in the bulb’s atomic lattice, to compensate for the losses in electrical power. The device also reacts to ambient heat in the room to increase its efficiency and power the bulb.

    This process cools the bulb slightly and could eventually be employed to manufacture “cold” bulbs that don’t generate any heat, only light. And, since the same physical mechanism from these tiny bulbs can be applied to any LED, they likely will be. Original Source via Physics.
    One day it will hopefully be a bit brighter

    - Matt

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    Flashaholic* mvyrmnd's Avatar
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    Default Re: 230% Efficient LEDs

    So if we run 100 billion XP-G's at 30 picowatts a piece, we'd be getting 6.9W of light for 3W of electricity. I think. That many zeros messes with my brain.

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    *Flashaholic* precisionworks's Avatar
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    Default Re: 230% Efficient LEDs

    the team was able to generate 69 picowatts of light
    69 X ( 10-12 ) watts. Or .000000000069 watts.
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    Default Re: 230% Efficient LEDs

    If the extra energy comes from the thermal energy in the bulb (waste or from its surroundings), I can see this going well in warm countries. People in colder climates will to turn up their heaters a bit more though...
    Finning does help dissipate heat. This is why the fins are removed before cooking fish. Otherwise it will throw off the heat and not reach the proper cooking temperature. --Duglite

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    Flashaholic* Mattaus's Avatar
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    Default Re: 230% Efficient LEDs

    Quote Originally Posted by Th232 View Post
    If the extra energy comes from the thermal energy in the bulb (waste or from its surroundings), I can see this going well in warm countries. People in colder climates will to turn up their heaters a bit more though...
    So what you're saying is that we'll be right here in (mostly) sunny Australia.

    It's a step in the right direction at least. The speed at which most things are advancing is insane these days, and just about the only thing that is not moving as fast as everything else is batteries. So we need to get more efficientl, though it wouldn't harm anyone if both improved hand in hand.

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    *Flashaholic* StarHalo's Avatar
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    Default Re: 230% Efficient LEDs

    I wonder if 69 picowatt emitters would work in night vision display equipment..

  8. #8
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    Default Re: 230% Efficient LEDs

    Quote Originally Posted by Mattaus View Post
    It's a step in the right direction at least. The speed at which most things are advancing is insane these days, and just about the only thing that is not moving as fast as everything else is batteries. So we need to get more efficientl, though it wouldn't harm anyone if both improved hand in hand.
    You just made me realise something. My titanium lights with their lower thermal conductivity will perform better than my Al lights, which will take away all that valuable heat from the LED and waste it heating the surrounding air. That would be really funny to see.
    Finning does help dissipate heat. This is why the fins are removed before cooking fish. Otherwise it will throw off the heat and not reach the proper cooking temperature. --Duglite

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    Default Re: 230% Efficient LEDs

    So does that mean we should throw away our heatsinks?

    Not sure how they "harness" the waste heat; maybe uber-micro stirling engines?

  10. #10
    Flashaholic* Mattaus's Avatar
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    Default Re: 230% Efficient LEDs

    Quote Originally Posted by Th232 View Post
    You just made me realise something. My titanium lights with their lower thermal conductivity will perform better than my Al lights, which will take away all that valuable heat from the LED and waste it heating the surrounding air. That would be really funny to see.
    Actually the heat sinking practices we currently all strive to implement would become null and void...flashlight design would/could change dramatically. I am of course only thinking about flashlight applications here. I'm sure there are many more far reaching implications.

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    *Flashaholic* StarHalo's Avatar
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    Default Re: 230% Efficient LEDs

    69 picowatts isn't enough for any sort of lighting application..

    But if you can indeed see very few or individual photons in total darkness, as has been posited here, then a bunch of these micro-output micro-LEDs could work in night vision display of some sort..

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    Flashaholic* AnAppleSnail's Avatar
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    Default Re: 230% Efficient LEDs

    Quote Originally Posted by StarHalo View Post
    69 picowatts isn't enough for any sort of lighting application...
    I dunno, you'd only need about 21 million of these to produce almost a whole lumen in green light.


    My biggest light-hog is my camera.

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    Default Re: 230% Efficient LEDs

    There ARE some members here who would BUY a light that put out a 1/21,000,000 lumen "Firefly" mode.



    And there would be some others who would complain THAT'S too bright.


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    *Flashaholic* StarHalo's Avatar
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    Default Re: 230% Efficient LEDs

    Quote Originally Posted by AnAppleSnail View Post
    I dunno, you'd only need about 21 million of these to produce almost a whole lumen in green light.
    Your average low-res camera display has about 200,000 pixels in it; that would be .01 lumens total by the math, which would be absolutely visible in total darkness..

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    Default Re: 230% Efficient LEDs

    Quote Originally Posted by StarHalo View Post
    Your average low-res camera display has about 200,000 pixels in it; that would be .01 lumens total by the math, which would be absolutely visible in total darkness..
    How do you know that 0.01 lumens, spread out over an unknown area, would be visible?

    It would essentially have to be concentrated enough to put lux on something to see.

    Or do you mean you see an application for a light source the size of a 200k pixel camera display working as some sort of 0.01 lumen indicator light, as in the screen sized source would glow faintly, and that would be useful because you could see it if it were otherwise pitch black, and your eyes were night adapted?



    I think we can just wait for cold fusion...it should be ready any time now...

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    *Flashaholic* StarHalo's Avatar
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    Default Re: 230% Efficient LEDs

    As in a display, you're staring into the emitters; a 0.01 lumen total display should be plainly visible to dark adjusted eyes..

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    *Flashaholic* fyrstormer's Avatar
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    Default Re: 230% Efficient LEDs

    It sounds like it works similarly to laser cooling; when the metal's electron-plasma field is vibrating at its resonant frequency, any input energy increases the brightness of the light emitted -- even if that energy comes from the temperature-induced random vibration of the metal's nuclei.

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    Flashaholic* AnAppleSnail's Avatar
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    Default Re: 230% Efficient LEDs

    Quote Originally Posted by fyrstormer View Post
    It sounds like it works similarly to laser cooling; when the metal's electron-plasma field is vibrating at its resonant frequency, any input energy increases the brightness of the light emitted -- even if that energy comes from the temperature-induced random vibration of the metal's nuclei.
    I didn't see information about what wavelengths are emitted. Are their lattice vibrations "useful" light, or are we talking infrared warming of an LED here?
    My biggest light-hog is my camera.

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    *Flashaholic* fyrstormer's Avatar
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    Default Re: 230% Efficient LEDs

    I'm not sure you can get useful light at any wavelength with an input power of 69 picowatts. Pragmatism aside, as far as I know an LED will *always* produce its intended color of light as long as the drive voltage is within spec, regardless of how tiny the amperage may be.

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    Flashaholic* znomit's Avatar
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    Default Re: 230% Efficient LEDs

    We need to know how big the die is. I'm thinking a few trillion of these mounted to my ceiling to provide light and cooling.

    Should save me a few bucks in power.

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    Flashaholic* monkeyboy's Avatar
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    Default Re: 230% Efficient LEDs

    Quote Originally Posted by mvyrmnd View Post
    So if we run 100 billion XP-G's at 30 picowatts a piece, we'd be getting 6.9W of light for 3W of electricity. I think. That many zeros messes with my brain.
    Interesting idea. Back-of-the-envelope calculation:

    You'd need an area of 1.5 km x 1.5 km and more money than Bill Gates. Not sure you'd even be able to see a dim glow with 6.9W spread over that area. Imagine the cabling you would need and the power losses through that length of cabling!

    How about this for an idea: put the die in contact with an efficient photovoltaic solar cell which simultaneously powers the die and extracts energy from it, and you have a machine that extracts heat from the environment and directly produces electricity. I'm sure that violates every law of thermodynamics though.

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    Flashaholic* mvyrmnd's Avatar
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    Default

    Quote Originally Posted by monkeyboy View Post

    How about this for an idea: put the die in contact with an efficient photovoltaic solar cell which simultaneously powers the die and extracts energy from it, and you have a machine that extracts heat from the environment and directly produces electricity. I'm sure that violates every law of thermodynamics though.
    It would only break the rules if it ran forever. With no external input of power after the initial power up, it would simply fade out over time.

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    Flashaholic* uk_caver's Avatar
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    Default Re: 230% Efficient LEDs

    Quote Originally Posted by monkeyboy View Post
    You'd need an area of 1.5 km x 1.5 km and more money than Bill Gates. Not sure you'd even be able to see a dim glow with 6.9W spread over that area. Imagine the cabling you would need and the power losses through that length of cabling!
    If starlight is ~10^-4 lux(10^-4lm/m^2), with white light at ~350lm/W the 6.9W of light would be 2400lm, spread over the 1.5x1.5km, about 10x as bright as starlight, if I haven't screwed up calculations.

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    Flashaholic* AnAppleSnail's Avatar
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    Default Re: 230% Efficient LEDs

    Quote Originally Posted by fyrstormer View Post
    I'm not sure you can get useful light at any wavelength with an input power of 69 picowatts. Pragmatism aside, as far as I know an LED will *always* produce its intended color of light as long as the drive voltage is within spec, regardless of how tiny the amperage may be.
    They say they have an LED with a "very small band gap." To me that means low-energy photons. ie, they have produced an infrared LED emitting 'bonus' infrared light.
    My biggest light-hog is my camera.

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    Flashaholic* uk_caver's Avatar
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    Default Re: 230% Efficient LEDs

    If so, when they say 'these initial results provide too little light for most applications', I wonder what applications there would be for a very dim infrared LED?

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    Default Re: 230% Efficient LEDs

    My take on all this isn't that the LEDs in the experiment have any practical applications, but rather that the experiment helps to understand where the losses occur. This in turn could eventually lead to LEDs which are nearly 100% efficient. Once you get past 75% or 80% efficiency, small gains may not save you much power, but they could greatly decrease heat-sinking requirements. Going from 80% to 90% cuts your heat-sinking requirements roughly in half. Going to 95% cuts them in half again.

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    Flashaholic* AnAppleSnail's Avatar
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    Default Re: 230% Efficient LEDs

    Quote Originally Posted by uk_caver View Post
    If so, when they say 'these initial results provide too little light for most applications', I wonder what applications there would be for a very dim infrared LED?
    Either removing a few picowatts from something inefficiently, or it's only mentioned because the science journalists misinterpreted things, or else I'm misreading what the band gap means.
    My biggest light-hog is my camera.

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    *Flashaholic* fyrstormer's Avatar
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    Default Re: 230% Efficient LEDs

    Quote Originally Posted by uk_caver View Post
    If so, when they say 'these initial results provide too little light for most applications', I wonder what applications there would be for a very dim infrared LED?
    One application that comes to mind is a cooling surface for cryogenic experiments. The crystalline surface of the emitter would help the cryogenic substance radiate away its remaining heat.

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    Default Re: 230% Efficient LEDs

    I think you guys are looking at this the wrong way... We could cover our existing LED heatsinks with these LED and let them run off the heat, that way we can lave LED-powered LED!



    Yo dawg, I heard you like LED, so we put LED on your LED so your D can EL while your D EL's... (I'm new at this, forgive me)

    Someone had to say it.
    Last edited by ssvqwnp; 03-09-2012 at 11:39 AM.

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    Default Re: 230% Efficient LEDs

    ...........
    Last edited by ma_sha1; 03-09-2012 at 12:02 PM.
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