LED's Efficiency Exceeds 100% 502
New submitter Paul Fernhout writes "Physicists from MIT claim to have demonstrated that an LED can emit more optical power than the electrical power it consumes. Researchers suggest this LED acts like a heat pump somehow (abstract). Is it true that 230% efficient LEDs seem to violate first law of thermodynamics?"
They must have used the wrong cable (Score:5, Funny)
They must have used the wrong cable, causing the light to go faster than C and mess with their readings.
Re:They must have used the wrong cable (Score:5, Funny)
Re:They must have used the wrong cable (Score:5, Funny)
They could have reversed the polarity of the neutron flow, causing the LED to be coupled to the singularity driving the Time Lords' TARDISes.
Re:They must have used the wrong cable (Score:5, Funny)
I thought you had to reverse the tachyon polarity.
Now I'm all confused.
Re:They must have used the wrong cable (Score:5, Funny)
Ah! Monster cables are good for something after all.
Re:They must have used the wrong cable (Score:5, Funny)
They must have used the wrong cable, causing the light to go faster than C and mess with their readings.
It was obviously a Denon AKDL1 Dedicated Link Cable [amazon.com]
Re:They must have used the wrong cable (Score:5, Funny)
Nothing can go faster than C. Except Fortran, of course.
Re:They must have used the wrong cable (Score:5, Funny)
Thats too true.
Where C = Cost.
LED Cooling (Score:5, Informative)
Really puts a whole new perspective on LED clad 'gaming'-machines, which as you know - should have blue LEDs for cooling, and red LEDs for superior overclocking.
There *is* someone who can read! (Score:4, Insightful)
11 comments down and finally someone has actually understood enough of the summary to know that they aren't claiming that conservation of energy is dead.
Re:There *is* someone who can read! (Score:5, Funny)
Welcome to slashdot, "enjoy" your stay.
Re: (Score:3)
I want to see how this compares to cold cathodes. :)
Re: (Score:3)
I was thinking about California: all those malls that have lights on 24/7 for security wasting electricity while the AC blasts away to keep the malls cool when they are empty (to avoid having to cycle them hard in the morning). If they can scale this up a factor of ... 1x10^(12+2) ... ugh ... Nevermind.
Re:LED Cooling (Score:5, Funny)
Re:LED Cooling (Score:5, Informative)
Not really functional. Looking at the chart, this works in fairly high temperatures (the curve that exceeds 100% is at 135C) and exceptionally low power input and light output.
Basically they are stating that at extremely low voltage and very high ambient temperature, LED can convert a small portion of heat around itself into luminescence. While interesting, practical applications are going to be minimal due to temperature, power and output luminescence values.
Obligatory Simpsons Quote (Score:5, Funny)
"In this house we obey the laws of thermodynamics!"
Not breaking any laws (Score:5, Informative)
Re:Not breaking any laws (Score:5, Insightful)
Why? Entropic heat is energy, and so is light. What's so broken with converting one to the other?
Re:Not breaking any laws (Score:5, Insightful)
Re:Not breaking any laws (Score:5, Insightful)
Yes but taking advantage of entropic heat to generate coherent light would appear to violate the second law.
No, it doesn't, as long as the entropic heat being exploited costs more to organize than to disperse in the first place.
Namely: it would take more than the 39 picowatts of energy being generated to produce the heat to provide the additional 39 picowatts of energy.
The world is full of things that naively contradict the 2nd law of thermodynamics, because people misunderstand that you can have a localized violation of the 2nd law of thermodynamics, as long as the entire closed system that it is in counters that localized violation.
Re:Not breaking any laws (Score:5, Interesting)
It's already been pointed out that this doesn't violate the first law of thermodynamics, because heat is turned into light. However, it's less obvious how the second law of thermodynamics stays intact. The reason has to do with the temperature difference between the LED and its environment. Notice how the efficiency at room temperature is several orders of magnitude below 1, and only at 135 C do you see an efficiency greater than 1, and only for very, very small output powers. Really, they could have taken any old piece of metal and heated it to 135 C and measured the amount of light generated. It's known as the blackbody effect. The fact that it's an LED is completely irrelevant.
This is just foolish science. It happens all the time. Someone thinks they discovered something new, but really it can be completely understood from fundamental laws.
Re:Not breaking any laws (Score:4, Insightful)
Re:Not breaking any laws (Score:5, Informative)
1) Black body radiation cannot be turned on or off at will at constant temperature. What these guys have figured out is a way to turn it on or off using electric power.
2) Since it is an LED it emits a specific frequency range of (visible) light. Black body radiation emits all frequencies, but peaks at a frequency dependent on the temperature. I doubt the materials used would have any noticeable amount of visible light at 135C. These guys have managed to somehow convert all these varying frequencies into the natural frequency of the LED at 135C.
Re: (Score:3)
Yes but taking advantage of entropic heat to generate coherent light would appear to violate the second law.
Why? There's nothing in the second law that prevents heat from being transformed into light (coherent or not). In fact, this happens all the time. It's what causes hot objects to emit infrared radiation. My guess is that they're applying just enough voltage to the PN junction in the LED to lower the energy barrier to the point where thermally induced vibrations are enough to push the electrons into the holes.
Re:Not breaking any laws (Score:4, Informative)
In fact, it is very laser-like, but in solid, not gaseous form.
In a gas laser, you get the electrons in a whole bunch of molecules of gas into an excited state. Then you get a few photons of the desired frequency bouncing around in the gas and whenever they encounter an excited electron, it jumps back to the ground state releasing all of it's energy as a photon that's exactly in phase with the photon that triggered the collapse in the first place. This happens in a cascade effect and results in a massive release of all the energy in the gas at once.
If you could achieve that same effect in a solid, the atoms would be bunch up much closer together, meaning that you'd get many more released photons per volume.
One of the things I loved about Real Genius was how much of the science (aside from the hacking parts) made perfect sense.
In this LED, you have a laser-like situation. But instead of the energy being stored in the excited state of electrons, it's stored as kinetic energy.
An LED normally works by having the incoming electricity dump its energy into an electron that enters an excited state of some kind. I don't fully understand it, as it doesn't seem exactly analogous to the higher-orbital thing that happens in the gas in the laser example. But this electron moves through the material towards the other side, but eventually encounters a 'hole'. An energy gap in which there could be an electron, but there isn't right now. The hole and the electron combine and the electron gives up its energy as a photon.
Apparently, while heat is not normally enough to push the electrons around, and make them combine with holes spontaneously, the electrical current acts like some sort of ratcheting mechanism (like how flagella in bacteria take advantage of brownian motion) that allows the heat to push the electrons into holes. Though this is a guess and very rough analogy on my part.
The Law (Score:5, Informative)
For those wondering about conservation of energy, it's intact. The extra energy comes from heat / vibration in the system.
For those concerned about the second law of thermodynamics, it's not specifically addressed in the article, but the smart money's on entropy increasing in this experiment. The second "law" is really just statistics though (law of large numbers anyone?), and as with most statistics people are still arguing about what it really means. See http://en.wikipedia.org/wiki/Second_law_of_thermodynamics#Controversies and http://en.wikipedia.org/wiki/Fluctuation_theorem
Re:The Law (Score:4, Informative)
The second "law" is really just statistics though (law of large numbers anyone?), and as with most statistics people are still arguing about what it really means.
StackExchange now has a physics section, and this issue was very recently addressed:
http://physics.stackexchange.com/questions/21028/second-law-of-thermodynamics-why-is-it-only-almost-always-true-that-entropy-i [stackexchange.com]
against known laws? (Score:4, Funny)
Kvothe did it first (Score:5, Funny)
It's a good example. The hub of a wagon wheel will be warm to the touch. That heat comes from the motion of the wheel. A sympathist can make the energy go the other way, from heat into motion. I pointed to the lamp. Or from heat into light.
There was an art to choosing your projects in the Fishery. It didn't matter if you made the brightest sympathy lamp or the most efficient heat-funnel in the history of Artificing. Until someone bought it, you wouldn't make a bent penny of commission.
Article not as bold in its claim (Score:3)
A misleading and hyperbolic Slashdot story? (Score:3)
Wow I'm totally shocked, what's the world coming to? :) All you have to do is actually read the linked article to see there's no sort of thermodynamic violation of any sort implied, not that most of the people posting here will bother to RTFA.
There is some confusion here (Score:5, Funny)
as most people think Light Emitting Diode when they hear LED.
But in this experiment they are referring to a Large Entropic Dilemma.
So the results make perfect sense.
Pooooof (Score:3)
Now, all we need is a solar cell with 100% efficiency and we're in business.
Re: (Score:3)
Even if we could only get 50% efficiency- we've got ourselves an expensive device that will produce FREE electricity.
Heat Energy... (Score:4, Interesting)
Surely if this is true the "light" is not the big story.
If you can take "heat" and convert it into another form of energy that is HUUUUUUUGE NEWS- yes I know, steam engines, etc, but they require a large difference in temperature.
Imagine if your fridge/freezer- GENERATED power- by taking heat energy and converted it into electricity?
Re:Heat Energy... (Score:4, Interesting)
Good time to RFTA (Score:5, Informative)
Interesting to see the number of posts saying that this is absolutely not possible - reading through the article, it seems possible and maybe there is enough here to study the phenomena enough to warrant more investigations.
The LED seems to be emitting 69 picowatts (pico = 10^-12) when only 30 picowatts of electricity is being pumped in with a measurable decrease in the temperature of the LED. This implies that the LED is acting as a heat pump, converting heat energy into light. If you've ever seen a Peltier cooler in action (or worked through the operation), it seems like to me this is possible.
Note that the power level this phenomenon is observed at is extremely low - the result is maybe good enough for cooling a few molecules of beer - but I think there is something here that should be investigated to see if any usable applications could come out of it.
myke
Re:Good time to RFTA (Score:4, Insightful)
So far... only good enough for cooling a few molecules of beer.
The average man could outrun the first combustion-engine powered vehicles. The first modern computers took up entire rooms, were programmed with punchcards and were much less powerfull than the average 1990's cell phone.
We've got our foot in the door. What if we can improve on this the way we have with computers... and then put thousands of them in an array.
Cold? (Score:4, Interesting)
So the lights sucking the heat out of the air and feel physically cold to the touch?
Does this 230% conversion ration only work in really high heat location or is this in room temperature?
Would this technology not really work in -40 degree winter environments?
PN junctions are amazing. (Score:5, Insightful)
The semiconductor PN junction is amazing. That's what's fundamentally inside LEDs. When appropriately tuned, PN junctions (a) permit electron flow in only one direction, demonstrating their diode nature, (b) convert current into light, like an LED, (c) convert current into a heat differential, like a Peltier junction cooler, (d) convert light into current, like a photo cell, (e) convert heat differential into current, like a solid-state thermionic energy converter, (f) act like a voltage-tunable capacitor, like a varactor, and more. In fact, to a very coarse first approximation, all PN junctions exhibit each of these characteristics to a greater or lesser degree.
So what's this group done? Shown that an appropriately tuned PN junction (or stack of them, I'd imagine) can be used to simultaneously act as a solid-state thermionic energy converter *and* an LED. Thus, it converts applied electricity to photons, but also converts a heat differential to electricity, which gets converted to photons as well, meaning it's sucking heat out of its immediate evironment. Cool stuff, if you'll pardon the pun.
I saw something like this (Score:5, Interesting)
This is actually possible (Score:5, Informative)
This is not as incredible as it sounds. To explain how it works, it is perhaps easiest to start with a simpler device. I could take a brick, connect a battery to it and say "Look! This brick is only consuming one milliwatt of electric power, yet it is emitting one Watt of infrared radiation. That is 100 000 % efficiency!" If I did the same thing at 1 000 degrees Celcius, the brick would even be emitting visible light (wether connected to a battery or not.)
What the people at MIT do is a little more complicated. They don't use the black body radiation directly. Instead they take electrons that would have emitted infrared photons, add some more energy to them, and get visible light. For this to work, they only have to add the difference between the energy of an infrared photon and a visible photon, yet they get the light output of a visible photon. At a temperature of 135 degrees Celcius (that is 275 degrees Farenheit if you happen to live in Belize or the United States) the difference between the black body radiation and visible light was small enough that they managed to get over 100 % efficiency. No laws of thermodynamics were violated.
Incomplete summary (Score:3)
I would like to see the entire experiment rather than an incomplete summary. here are a few questions.
1. How long was this effect present?
2. What was the temperature of the LED as the power was decreased?
3. Was the same effect there if the power was started at 0V and slowly increased?
If it only was present for short periods while the power was decreased the effect might even be a capacitance release of power stored in the LED. In the lower efficiency phase electrons may be stored in the LED and released as the power gets lower.
I always knew... (Score:4, Funny)
Sundiver (Score:3)
In the book Sundiver by Robert L. Forward, a research ship traveling inside the Sun gets its drive sabotaged, and they escape by using the cooling laser as a drive, freezing everyone aboard.
Lasers are today used to cool to a few milli Kelvins, and below, very close to absolute zero temperature. The reflected colour of the laser is a little bit less pure, as the thermal vibrations are removed by increasing the entropy of the laser light.
The same principle is going on in this light diode.
Some form of Maxwell's daemon ? (Score:4, Interesting)
Is this some form of Maxwell's demon [wikipedia.org], having the same effect but in a way not so far envisaged ? It seems to me that it takes the heat energy, tops it up with some electrical energy and before that process can reverse it radiates the energy away as light. The radiating away has the effect of the trap door - preventing the reversal.
This device may not work well if there are many of them that can shine on each other, an incoming photon could knock an electron up into the conducting band leaving a hole behind and generating some heat. Thus to be useful the light that they generate would have to be directed away with little reflection.
Re:No (Score:5, Informative)
Re: (Score:3)
Thank you for that, TFS made it look like they somehow managed to overcome the laws of thermodynamics. I was going to ask you to explain farther but RTFA instead.
Re: (Score:3)
Re:No (Score:4, Interesting)
Not only silent, but you can beam the light to an external collector that produces electricity. It's like having a peltier element where the hot side can be in a different building.
Re:No (Score:5, Informative)
No it isn't fiddling with numbers. You are missing the heat pump bit.
The device is taking X amount of energy from the electricity supply and X * 1.3 of energy as thermal and converting this to X * 2.3 as light. i.e. it is 230% efficient when comparing light output to electrical input. Equally, it is 100% efficient when comparing light output to electrical and heat energy input combined.
This does take a little bit of thinking to get your head around but I have a more common example in the shed outside. It contains a heat pump which is 350% efficient. It takes 2kW from the electricity supply and outputs 7kW of heat energy to heat my house. The missing 5kW comes from the pipes in the garden as heat energy. The result being that the garden is slowly being cooled. http://en.wikipedia.org/wiki/Heat_pump [wikipedia.org]
Re:No (Score:5, Insightful)
Now, some people might still be bothered by this, because the idea of using ambient heat to do useful work is another one of those "perpetual motion machine" kind of claims. Heat represents a disordered (high-entropy) state, from which you cannot extract useful work. The relevant thought experiment here is the Brownian ratchet [wikipedia.org]: the idea being that you have a ratchet that gets bombarded by random molecular collisions (in water or air, say). The ratchet will turn foreward when a random collision is strong enough, and so over time you can use this turning motion to wind a spring and thus convert random thermal motion into stored energy. The reason this doesn't work in real life is because if random thermal motion is enough to overcome the pawl on the ratchet, then the pawl will be 'hot' enough that it will randomly and spontaneously lift up, turning the wheel backwards. The only way to avoid this is to have the pawl at a lower temperature than the rest of the mechanism: this works, but it's well-known that you can extract useful work from a thermal gradient, so the laws of thermodynamics remain intact.
Coming back to this present result, how does this device use ambient heat to generate useful photons? Sure, it acts as a thermoelectric cooler, establishing a local thermal gradient, but this sounds like 'cheating' in that it's a way to extract energy from the entropy of the surroundings! The very first sentence of the scientific paper [aps.org] addresses this:
Basically, the device is converting high-entropy thermal energy into even higher entropy incoherent electromagnetic radiation (light output). So, the second law of thermodynamics is not violated. Essentially, this device is acting as a way to connect thermal degrees of freedom to E&M degrees of freedom. The system, wanting to increase entropy as much as possible, tries to spread energy through all these degrees of freedom, which means creating some photons at the expense of some of the heat in the material.
It's a neat bit of physics, and will probably have implications for device efficiency and other applications.
Re:No (Score:5, Interesting)
It's a neat bit of physics, and will probably have implications for device efficiency and other applications.
It's the solution for global warming.
Take a large bank of these over-efficient LEDs. Shine them on a solar panel. Power the LEDs from the solar panel output. Everything in the vicinity of the LEDs gets cold. Make lots of these. Problem solved.
If it seems like a perpetual motion system, it probably is. If you've got a 230% efficient LED, then you can have a 50% efficient solar panel and still come out ahead.
The only problem is what to do with all the excess electricity these things will produce.
Re: (Score:3)
Yeah it's not the first law it violates but the second.
Re: (Score:3, Informative)
Or you could read the damn links and find out. But I guess easier to make guesses.
Re:No. (Score:5, Funny)
Re:No. (Score:5, Informative)
It says in the summary (and in the article) that the LED at very low electrical input levels, acts as a heat pump. It absorbs local heat energy and converts into photons.
So you get more light out than electricity in, because you're stealing heat and converting it to light. It's not more than 100% efficient, it's multiple energy sources being used. No breaking the laws of thermodynamics.
Re:No. (Score:5, Insightful)
Yeah, but man, a it's a completely solid state heat pump that dumps waste heat as usable light - now that's something. Just imagine: every server, instead of needing cooling, can have this stuck to the heatsink and mounted on a tall pole. No more datacenter, we'll have datapoles, and our streets will be full of them :)
Re:No. (Score:5, Funny)
Yeah, but man, a it's a completely solid state heat pump that dumps waste heat as usable light - now that's something. Just imagine: every server, instead of needing cooling, can have this stuck to the heatsink and mounted on a tall pole. No more datacenter, we'll have datapoles, and our streets will be full of them :)
You're not thinking like an evil genius. You've got a 10MW data center. You have a way to convert the heat load into light. And now you want to distribute it all over and make street lights out of it?
Whatever. I want my huge frackin' laser.
Re:No. (Score:5, Funny)
In theory.
Re:No. (Score:4, Insightful)
The LED is "consuming" external heat to produce the additional light. The article is pretty clear and an enjoyable read.
Re:No. (Score:5, Funny)
Read the article? Heck, I didn't finish the headline. As soon as I realized it didn't mention iPads I went straight to the comments to argue we should instead discuss iPads.
Why don't we have iPad 4 speculation yet?
1. I for one welcome our new iPad 4 overlords and their app that allows you to put hot grits on Natalie Portman and disguise it in a bad car analogy.
2. Ask if it runs Linux, and then cite another failed year of Linux on the desktop.
3. ???
4. Profit.
What were we talking about again?
Maybe (Score:5, Informative)
"30 picowatts and measured an output of 69 picowatts of light - an efficiency of 230%. The physical mechanisms worked the same as with any LED: when excited by the applied voltage, electrons and holes have a certain probability of generating photons. The researchers didn’t try to increase this probability, as some previous research has focused on, but instead took advantage of small amounts of excess heat to emit more power than consumed. This heat arises from vibrations in the device’s atomic lattice, which occur due to entropy."
They are not claiming more than 100% efficiency in total terms.
Re:Maybe (Score:5, Funny)
Re:Maybe (Score:4, Interesting)
In THIS house... (Score:5, Funny)
"That's a bright idea, he said coldly."
Also, heat-activated lighting. Also, if you can suck heat from the environment to make light, and then pump the light to solar cells to make electricity, you have a heat-to-electric converter.
Maxwell's demon must be rolling over in his randomly displaced bed right about now.
Re: (Score:3, Insightful)
People seem to forget that heat is power too. The room has heat either from the sun or because something else is using power to heat it (eg. furnance). Either way the energy isn't free it's coming from somewhere (cooling room, sun etc).
Re:Maybe (Score:5, Insightful)
People seem to forget that heat is power too.
People seem to forget that energy is not power.
Re:Maybe (Score:5, Funny)
If I controlled all the energy, I would have all the power!
Re:Maybe (Score:4, Insightful)
Re:Maybe (Score:5, Insightful)
Heat is only an energy store if there's some cooler place for that heat to flow to. If you can make use of the heat in a room in such a way that it maks part of the room cooler, and another part warmer, thne you're producing energy. If that exceeds the energy you have to feed in to make it happen, you have a perpetual motion machine.
It's not obvious how this LED works in this regard - it's quite unlikely that it's a net energy gain, but it doesn't seem to be the same transfer as a cooling laser.
Re:Maybe (Score:5, Funny)
It's tapping into the grid! Awsome!
Now someone go hook that LED up to a 50% efficient enclosing PV panel.
Re:Maybe (Score:5, Interesting)
No, and they are using an LED in the far IF spectrum at elevated temperatures. Actually the effect is difficult to distinguish from thermal radiation - a darkening of the LED might also explain it (?). Still, I think the paper is genuine, and under very specific circumstances a combination of thermal and electric energy can power an LED.
The bigger question is: can this be achieved in any real scenario, and not just in minimal amount? That is going to be much tougher.
Re:Maybe (Score:5, Interesting)
I think this could be applied as an interesting method to cool an object by applying a voltage to it... if it consumes both the energy of the voltage and the ambient temperature of the device.
Re:Maybe (Score:5, Funny)
So, you're saying that future computers, if we don't want to spring for fans or liquid cooling, will have to be lit up like a modder's case?
I guess that's great if you like your server rooms to also double as sweet rave parties.
Re:Maybe (Score:5, Funny)
How the hell are you supposed to sleep in a server room like that?
Re:Maybe (Score:4, Informative)
Re:Maybe (Score:5, Interesting)
Sounds like the LED is effectively re-directing the thermal radiation then, which is kind of cool. (No pun intended.) Could you daisy-chain this so the light output of one super-powers the next to draw heat away from a source? You'd be siphoning off as much heat energy from the system as the electric energy you're putting in in that case.
The second law of thermodynamics (Score:5, Informative)
This is not violating the first law of thermo (energy conservation). It is getting the energy it needs from it's environment.
However it might possibly be violating the second law of thermo. Turning heat into light at high efficiency should not be sustainable. energy in the form of light has more less entropy than energy in the form of heat.
I could imagine that, in burst mode, that some energy is somehow being stored so that it can when triggered temporarily emit more or seemingly defy entropy. For example perhaps the crystal lattice is disorganizing during emission and then self healing to an organized state over time. This would be taking energy from the environment and shedding entropy to the environment and not neccessarily viloating any laws.
So some game is being played and I'm surprised anyone would publish the findings without an explanation for this.
Re:The second law of thermodynamics (Score:5, Informative)
It isn't violating the second law for the same reason it's not violating the first -- the system in question is bigger than the LED itself. It includes the environment from which it is obtaining its energy. Local decreases in entropy are not disallowed.
Re:Maybe (Score:5, Funny)
Did they check to see if their time servers are synced properly? Maybe the power is time-travelling from a previous test.
Re:No (Score:5, Informative)
According to TFA, they are actually taking advantage of other sources of energy in addition to the electricity provided by the wall plug. So it's not really the LED getting "greater than 100% efficiency", it's really "producing more light than you would get if you only took advantage of the electricity from the wall plug".
And they're talking in the range of 69 picowatts of light output, using only 30 picowatts of "wall plug" energy input. So it's quite believable.
Re:No (Score:5, Informative)
Yes, to say 230% efficient is really a false statement. There's no violation of thermodynamics, it's just that the LED has more energy sources than the electrons it's drawing down the wire.
Re:No (Score:5, Funny)
The fun trick will be to point this at a 45% efficient photovoltaic panel to generate the electricity.
Re:No (Score:4, Informative)
> The fun trick will be to point this at a 45% efficient photovoltaic panel to generate the electricity.
No chance, at 2.5um that is even theoretically impossible. Higher efficiency requires much shorter wavelength.
Re:No (Score:5, Funny)
Re:No (Score:5, Funny)
Monster Cable TOSLink?
Re: (Score:3)
When you visit a hardware store, and see a pack of incandescent bulbs that advertise 100% efficiency, you should thank the law of thermodynamics for obfuscating yet another specification.
Re:No (Score:5, Interesting)
Yes, to say 230% efficient is really a false statement.
Depends on your perspective. If you are selling these as LED light bulbs that output twice as much energy then they take from the wall plug, then yes, they are 200% efficient. They don't output more energy than what is put into the system, but they do output more energy than you put into the system and since we are all (as a species) self-centered egomaniacs, that is all that matters and the terminology is correct (for the audience).
Comment removed (Score:5, Interesting)
Re:Combine with a greater than 80% solar cell (Score:5, Funny)
Re: (Score:3)
That was my first thought. Even the explanation of the extra energy coming from heat is nice and doesn't stop solar cell from working. Might actually work well together: the cell is going to leak heat, this will soak it up.
Re: (Score:3)
Given that we can cool stuff down to less than a nanokelvin IIRC, and it took some ingenuity (Nobel prize for Bose-Einstein condensate), I doubt this LED will come anywhere close.
Re:Nothing violates the first law in this universe (Score:4, Informative)
No, it is not. The linked article is quite clear: the LEDs are geting colder, so the extra power output comes from the environment.
Now, 230% efficiency suggests that it is operating as a >100% efficiency heat pump, and that's also impossible. It might be decomposing itself in an endothermic(sp?) chemical reaction, or something.
It's not impossible. Heat pumps are routinely of greater than 100 percent efficiency, because they don't measure the input heat, just the output heat and the input electricity. Sure, it's a marketing scam, but what-r-ya gonna do?
Re: (Score:3)
Re: (Score:3)
I've always wondered how glowing metal aligns with the second law of thermodynamics. It seems to directly convert heat (lower order energy) to light.
Heat is not an inescapable sink of energy. It's just that at a large scale, entropy (including heat) must increase.
When metal glows when hot is it consuming anything or utilizing the difference in temperature in some way?
It's losing heat. If a block of metal emits 1 J of light, it cools by 1 J.
Or said another way, if you put a piece of metal in a perfectly insulated hot box would it still glow forever?
A piece of metal in an insulated box, as one would normally think of it, still has two items interacting thermodynamically: the block of metal and the inside of the box. If the metal is magically suspended in the box and the box otherwise contains a vacuum, then there is no conduction or convection between the box and the
Re: (Score:3)
For example, is the LED getting colder? Could it be converting heat to electricity?
Wow, yeah they should look into that...Oh wait, they already did and the LED is indeed getting colder and they postulate that it is converting heat into light.
4/1 coming early this year? (Score:3, Interesting)
While my knowledge and understanding is limited I think that the extra power in the light output comes from heat. So light power out is greater than electrical power in but if you consider thermal power AND electrical power then total efficiency is under 100%. Thus the first law of thermal dynamics is safe.
Only temporarily. If this device is converting heat into light as a byproduct of converting electricity into light, it's still LESS THAN 100% efficient, it just means it's getting the energy from the environment around it, NOT making it itself, OR it is using its own internal heat, meaning the longer it does this trick, the colder it gets. This provides a fundamental limit, namely 0 Kelvins, assuming it can even operate at all anywhere near that cold. Once it reaches this temp., it should start operating
Re: (Score:3)
Re:Can I place my order... (Score:5, Funny)
It sounds like it violates the 2nd and 3rd laws of thermodynamics if not the first.
The first law of thermodynamic is...you do not talk about thermodynamics :)