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LED's Efficiency Exceeds 100%
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, causing the light to go faster than C and mess with their readings.
Exceeds 100% ELECTRICAL efficiency is the key here. The conservation of energy is still intact because it supposedly uses heat energy to supplement.
So if I get the article right - LED cooling?
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.
Or you could read the damn links and find out. But I guess easier to make guesses.
"In this house we obey the laws of thermodynamics!"
My sci-fi novel, Ghost Thief, is now available from Amazon.com.
From the article: "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." The other thing to note is that these LEDs are being run at REALLY low power.
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
"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.
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
These guys must have been hanging out with Martin Fleischmann and Stanley Pons .
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.
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The lasers mounted on their 'Symmetric Hybrid Analogue Reflecting Chronometer' bounced back doubling the measured light output.
No brain, no pain.
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.
I'm out of my mind right now, but feel free to leave a message.....
Definitely GPS timing error.
Never say never. Ah!! I did it again!
From the article: "In their experiments, the researchers reduced the LED’s input power to just 30 picowatts and measured an output of 69 picowatts of light - an efficiency of 230%." It only would violate the conservation of energy if it converted the electricity to more electricity than came in. It's just converting the electricity into light very efficiently with a great ratio.
Nothing is more dangerous than a programmer with a screwdriver.
The LED is "consuming" external heat to produce the additional light. The article is pretty clear and an enjoyable read.
"Physicists from MIT claim to have demonstrated that an LED can emit more optical power than the electrical power it consumes. "
Bazinga!!
Global warming to the rescue!
To offset political mods, replace Flamebait with Insightful.
for a glow-in-the-dark refrigerator now?
It sounds like it violates the 2nd and 3rd laws of thermodynamics if not the first.
We are the 198 proof..
So if you had enough of these, you could air condition your house with them?
In theory, practice and theory are the same. In practice, they're not.
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.
I didn't follow through to the abstract, but the article didn't claim to be creating net energy. There could be other causes for more net energy emitted than applied, such as the device being on fire.
Gently reply
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.
It seems to me that it's just fiddling with the numbers; it isn'r really ">100%", it's "better than 100% when compared to higher power levels."
I did expect a better article from Psysorg. I'm still not completely clear on it, but it seems to have no practical value, only an academic excersize.
Free Martian Whores!
From the Article: "When the LED gets more than 100% electrically efficient, it starts to cool itself down, which is another way of saying that it's stealing energy (in the form of heat) from its environment and converting that heat into those over-unity photons." The article doesnt say what happens when the led finishes cooling down. is it still above 100% efficient?
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.
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.
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.
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Now, all we need is a solar cell with 100% efficiency and we're in business.
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.
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?
"That's the way to do it" - Punch
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.
The world's burning. Moped Jesus spotted on I50. Details at 11.
No, it's not even using the electricity to generate light for the most part. The electricity is effectively reducing the remaining threshold needed for ambient heat to be converted to light. In terms of overall energy efficiency, one would find it would still be under 100% if the amount of ambient heat lost could be measured.
Viable Slashdot alternatives: https://pipedot.org/ and http://soylentnews.org/
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
Mimetics Inc. Twitter
A new entrant into the solid-state heat pumps field would be rather nice... I wonder if they can get this thing to scale up a bit?
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 :)
A successful API design takes a mixture of software design and pedagogy.
Is this effect they are explaining similar to how a piece of metal will glow when hot? 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.
When metal glows when hot is it consuming anything or utilizing the difference in temperature in some way?
Or said another way, if you put a piece of metal in a perfectly insulated hot box would it still glow forever?
For example, is the LED getting colder? Could it be converting heat to electricity? Are magnetic fields near them weaker? Is the LED losing a minute amount of mass?
Can we try it again with 100 LED set at low power?
Can we set up a closed loop of a series of low power LED's illuminating a photovoltaic board?
excitingthingstodo.blogspot.com
Obligatory wanna bet?
In their experiments, the researchers reduced the LED’s input power to just 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.
This light-emitting process cools the LED slightly, making it operate similar to a thermoelectric cooler. Although the cooling is insufficient to provide practical cooling at room temperature, it could potentially be used for designing lights that don’t generate heat. When used as a heat pump, the device might be useful for solid-state cooling applications or even power generation.
Then that means at some level they have made a solid state heat pump that rejects the waste heat as light. /cool
-nB
*chuckles*
whois gawk date unzip strip find touch finger mount join nice man top fsck grep eject more yes exit umount sleep dump
Yea, I'm sure the research team didn't think to check their equipment after repeatedly getting totally off-the-wall results.
Or, you could try reading summary.
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
A third option is that you didn't read the article.
You must be new here...
-Arthur
Cave ne ante ullas catapultas ambules
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.
A successful API design takes a mixture of software design and pedagogy.
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?
http://blindscribblings.com - Tasty pop-culture in conceptual fashion.
To achieve this "above unity" efficiency, they are running these LEDs at 135 degrees C with a "light power" of 10^-10 watts.
So essentially, from my not-very-good understanding, they are able to exploit the motion of particles in the lattice due to heat (Kb*T) to overcome the energy gap in the diode. Hence the high temperature. I assume the wattage input must be kept low enough to not completely overpower this phenomena.
I would thusly conclude that the only reason why it can keep going with this >1 efficiency is because of the heat being supplied to the chamber in addition to the energy through electricity. Take away the heat, and it would slowly cool itself down.
How many orders of magnitude is 'a bit' in your world?
Faster! Faster! Faster would be better!
When used as a heat pump, the device might be useful for solid-state cooling applications...
The logical conclusion is, of course, a glowing refrigerator.
I support this line of inquiry.
Didn't David Brin use this idea with lasers to keep his sun skimming ship cool, or did I dream that?
I can see a practical application right off the bat - completely silent cooling for computers and satellites. As I understand, particularly the latter is a huge pain in the ass for engineers.
I did RTFA but do have a thermodynamics question.
Thermodynamics is based on the idea that energy can be changed from one form to another, but it cannot be created or destroyed. It also supposes that the total amount of energy and matter in the Universe remains constant, merely changing from one form to another.
The second half of that appears to be wrong the total amount of energy and matter in the universe does not remain constant by my limited understanding of quantum mechanics and membrane theory. Potential particles are converted to particles of matter as they emerge from the plank level as a wave form.
Did I miss something?
Even better yet, what morons made ignorant comments that were fully explained in the article?
The fun trick will be to point this at a 45% efficient photovoltaic panel to generate the electricity.
"Who is the Journal of Quantum Physics going to believe?" --Stephen Hawking
This is why I love Slashdot- really BRIGHT news.
So shiny, and if these LEDs work, splendidly brilliant!
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?
Troll is not a replacement for I disagree.
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
wot no sig
No, no, it is greater than 100% if you only count the incoming electrical power. They supplied 30 picowatts of power, and got 69 picowatts of light energy out. But the sample also became very slightly cooler.
Need a Python, C++, Unix, Linux develop
I think maybe your humor detector has the loose connection. AC was referring to the FTL readings posted here a while back, where a faulty cable was apparently to blame.
Tic-Tac-Toe, Global Thermonuclear War, and relationships all have the same winning move.
Like the recent faster than light that turned out to be a loose cable, lets see if others can duplicate those results.
In theory.
I'm out of my mind right now, but feel free to leave a message.....
Yes, as long as you shine the excess light somewhere outside. Though the question is how big the cooling panel with "enough of these" will be.
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: 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 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.
And the correct answer is... wait for it... AC didn't RTFA!
Tell that to the 350% efficient (measured) heat pump I have in the shed....
wot no sig
Entropy-powered LEDs?
from TFA:
[...]instead took advantage of small amounts of excess heat to emit more power than consumed. This heat arises from vibrations in the deviceâ(TM)s atomic lattice, which occur due to entropy.
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.
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
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?
When our name is on the back of your car, we're behind you all the way!
Great, so does this mean if we can make a 44% efficient solar panel, we have a way to generate electricity from heat caused by entropy?
Does that mean I can eventually use such a system instead of an A/C unit?
Sdelat' Ameriku velikoy Snova!
NO, actually they don't "need to take a look at what their 'closed system' is", because they already have and they tell you where that energy is coming from.
The truth is that all men having power ought to be mistrusted. James Madison
I once observed a low threshold LED (has a much less than 1.4V on-voltage) that was only attached by one lead, with the other lead hanging freely in space. The LED was quite clearly "on". When you put your finger closer to the free hanging lead (but not touch) it got brighter. It was just acting as an antenna in a room with lots of EM radiation around, and the induced current was enough to light it up.
"I have never let my schooling interfere with my education." - Mark Twain
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.
*NEWS FLASH* The internal combustion engine used worldwide for over a century produces a jillion percent more output power than the electrical input power used to fire the spark plugs.
Or you made a mistake by not reading the article.
You are welcome on my lawn.
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.
Yeah it's not the first law it violates but the second.
Great news, especially with incoming global warming. We create a power loop of LED's and tuned solar cells, such that the electrical efficiency is >100%. If the LED is 230% efficient then the solar cell needs to be around 44% or so. We don't care about waste heat as the device is actually a heat to electrical converter. So waste heat gets sucked back in. The real enegy source is the sun which heats the planet.
Yes it is on a small scale but integrated and packaged and stacked we get air conditioners that produce power.
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.
The important thought most people seem to be missing is that your house gets warmer. People are forgetting that while the LEDs are getting cooler, somewhere is a battery or power plant on the other side of the circuit that must be getting hotter. And it must be getting hotter by more than the LEDs are cooled.
Now how the hell do we make a trillion of these?
I see the gentleman from Foxconn in the corner of the room raising his hand.
"That's the way to do it" - Punch
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.
> 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.
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 at below 100% efficiency, per the laws of thermodynamics.
Don't get me wrong, if they have figured out a reverse amplifier transistor, one that uses a small current to bias a PN junction, and then receives energy from the background, they've effectively done what Tesla was trying to do around the time he died, just in a completely different way, making a device that can receive the sun's power indirectly, like an antenna, only it would use the environment itself as the antenna, the very air around it.
Of course, at the picowatt level, unless they can use 22nm or smaller silicon printing tech to make HUGE numbers of these, I would think they'd be prohibitively expensive. People concerned with what color light they output are not seeing the big picture. This allows us to finally, (and don't mod this funny, I'm not joking) use solar power 24 hours a day, since the sun bakes the earth, and the heat remains even at night, (unless you're some poor SOB who lives in Northern Montana, at high altitude where the temp in the dead of winter, at night, gets real close to absolute zero, they say...)
I once had an idea like this myself, but never pursued it. My version used conventional refrigeration... It feels good to be vindicated. Guess I should have thrown caution to the wind and built that prototype after all.
Or, just maybe... they cocked up the experiment, which seems vastly more likely, or they're making it up. Is a bit odd for the usual Slashdot April 1 bullshit. But just to throw this out there, remember everyone, grown men are prone to playing idiotic pranks and getting a cheap thrill from believing others believe them when they make shit up, and feel that at the close of March, each year, that some archaic change to a calendar is adequate excuse to give in to those urges, and act like children. I do not look forward to this particular time of year.
It's not even remotely believable.
They're only measuring one thing. Basically, it's a nice efficient LED, sure, but this isn't 100% efficient. Essentially, they're only controlling
watts energy: light
and not energy: energy.
So is it any surprise? There's probably a lot of heat as mentioned which is given off at the same time.
Picowatts are very very dinky. 65 pocowatts of light would be useless for a display, but what about fiber optic processors? What kind of light do they use? One of the problems in normal processors is heat. It would be nice to use the heat generated to produce more light (that you are using to do your processing).
Doubtful -- as the article describes, the LED is drawing on the heat caused by the vibrations of its own molecules "due to entropy." We're talking about amounts of energy measured in picowatts -- this is not going to be noticeable to the touch.
Unless someone's made a very big breakthrough, you cannot get energy from heat. Not by itself. Otherwise we'd have generators you can drop into a fire and get say, electricity from. Or just stick the generator in a room and let it "suck the heat out", that'd make a marvelous air conditioner, that actually produced power. I think if that was even remotely possible we'd see those for sale by now.
What you can do is extract energy from a difference in heat. Too many examples to mention, but a sterling engine and a peltier are probably the best examples.
On an atomic scale, thermal energy is like kinetic energy, since heat is vibration. A ball flying through space has energy, but you can't just suck it out. You have to intract it with something with a different vector. In the interaction, you can extract energy from the system. It's the same with heat - you can only extract energy when interacting it with something of a different temperature.
Or you could compare it with magnets. You can't "get energy" from a magnet. But you CAN get energy out of the system of a magnet interacting with another magnet or ferrous metal etc.
So there's no way for this LED to "get energy from heat". I wonder if they are heating it up by powering it normally (below unity), and then dropping it way down in power, and changing some of that heat back into power while cooling the LED down closer to room temperature? Considering the absurdly low power levels they're using to test it, it would not surprise me if there was some recovery of electrical energy from the cooling process. But they didn't say what they did to the LED immediately before the test.
Usually when someone is claiming above unity, there's additional input of energy somewhere else that's not immediately obvious. Just a matter of careful examination of the circumstances and comparison of the pre- and post-test conditions.
Check here for some ideas on how to spot this subtle input of energy. Look specifically at the "Rubber Band Heat Engine" for an example that may apply here with these LEDs.
I work for the Department of Redundancy Department.
I wouldn't say it is a scam but it is misleading if you don't understand where the extra energy comes from, but then who cares as heat pumps are much more efficient at heating and cooling a house than a furnace, resistive heating elements, and air conditioners.
Time to offend someone
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.
I was taking a swipe at the sensationalized excerpt slashdot posted. ("Is it true that 230% efficient LEDs seem to violate first law of thermodynamics?")
If you want us to believe that this thing is "acting as a heat pump" (actually the opposite), start by defining the heat source and heat sink.
If it's the moral equivalent of black-body radiation, say so, even though that makes it boring.
As it stands, TFA seems to imply that the thing cools itself below the temperature of its environment by ejecting energy as light, which I'm pretty sure violates at least one law of thermodynamics. (Yes, I know Brin proposed the same idea in Sundiver, and says that a couple of Nobel laureates couldn't find anything wrong with it, but I didn't buy it then, and I'm still not buying it now.)
To me, it looks like another classic pathological-science result -- only discernible at levels close to various noise thresholds, and not backed by a reasonable theory. But I'm a layman, so what do I know?
We all want to not believe but certainly imagine, hope, wish or dream that one of the main laws governing our universe is, finally, breached. I mean: we all know that the answer is "no". Heat pump, taking energy from the environment, thermodynamics laws still holding in the greater surrounding system, blah, blah, blah. But...well. How nice would it be. Just like this hardrocker making an ultra-fast slide on his guitar and yelling "Einstein was wrong". ( Was that AC/DC ? )
Religous speak to God. Insane are spoken to by God. When all shut up, one can finally hear Shostakovich in peace
If an ultra efficient solar panel was added to a setup with this LED could it power itself with AND generate power to spare?
For every benefit you receive a tax is levied. - Ralph Waldo Emerson
Reminds me of the Troll Science cartoons from 4chan. "shine led at pv cell... INFINITE ENERGY PROBLEM XCEL???"
So, if I don't see every article Slashdot posts, I have no sense of humor?
Without the context it just looks like another stupid "I know better than the experts" post.
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
since they give off more energy than it takes to light them up, all i have to do is buy a bunch of these and point a solar panel at them! INFINITE POWER!
i could live a little longer in this prison
So would that mean that it's sucking down 100% of the electrons that are coming down the wire? Man, think of your power bill!
It doesn't mean much now, it's built for the future.
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run it through the faster than light cables too
When I visit the hardware store and see a Mr Fusion on the shelf I should be able to use the efficiency rating to see how much matter it converts to energy then. Apparently thats only 3 years away now
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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.
Some drink at the fountain of knowledge. Others just gargle.
Aren't they measuring efficacy, not efficiency?
In theory.
Thanks Data. :-)
It must have been something you assimilated. . . .
This reminds me of David Brin's "refrigerator laser" concept from his book "Sundiver". The idea was that the laser was many times hotter than the sun, so you could shoot a laser out from your ship to take net heat out, while cooling the ship as it explored into the surface of the sun. Obviously heat would have to have been converted into light in this fictional concept.
Is this another case where a science fiction author proves prophetic?
--PeterM
They also recieved a message from a parallel dimension:
"pump not stop not stop we not stop pump we not hear danger not hear not hear you stop please stop you stop so we stop please you stop danger danger danger stop stop you stop pump"
Pumping out energy in wave form in the narrow band of energy we view as visible light is not the same as emitting energy across the entire spectrum, from IR (heat) to UV (rave light).
So, in short, no. Revel in your LED-equipped overlords.
-- Tigger warning: This post may contain tiggers! --
... it would add a new more truthful meaning to "cool lights".
now we need to go OSS in diesel cars
From the article:
As the researchers explain in their study, the key to achieving a power conversion efficiency above 100%, i.e., âoeunity efficiency,â is to greatly decrease the applied voltage. According to their calculations, as the voltage is halved, the input power is decreased by a factor of 4, while the emitted light power scales linearly with voltage so that itâ(TM)s also only halved. In other words, an LEDâ(TM)s efficiency increases as its output power decreases. (The inverse of this relationship - that LED efficiency decreases as its output power increases - is one of the biggest hurdles in designing bright, efficient LED lights.)
Or just change the definition of power to only mean one input instead of all inputs (leaving out the heat energy that is also converted). By doing that, I can claim that my 1969 VW achieves a power conversion efficiency above 100%, too - assuming I am going down hill, with a strong tail wind and the engine at idle.
This fails for two reasons. The solar panel efficiency so still so low that it would produce less power than went in to produce the light. And the additional energy comes from ambient heat.
Think of an air-conditioner. You put energy in through the power cord. More energy comes out the condenser in the form of heat. That's because the evaporator is getting cold, drawing in heat. The output energy is the combination of all sources of input heat. Now if you find a means to convert that output heat to electrical energy to power the device, you can have some real fun. But even then you won't achieve free energy since the best you can do is move it around. But I do think there is some small potential to improve the process.
Scaled up, we might have LEDs that can pump heat away for some practical purpose, like cooling CPUs. If that can work, then some day in the future you might have a CPU (more likely a million SoCs on one chip) that is emitting an intense light from the top of its surface. That would be the new heat sink. Now you need to get rid of the light, or the heat from that light hitting another surface. But this would be a better way of cooling since that is easier to convert back to something useful.
now we need to go OSS in diesel cars
ugh. fine. i'll point TWO solar panels at them. DOUBLE INFINITE POWER!
i could live a little longer in this prison
The overunity people just collectively heard the sound of cash registers. "Look it's proven by people from MIT. Our new device harnesses the power of LED at the atomic level."
Meanwhile, Steorn Ltd. calls up their investors and tells them there's been a breakthrough coming from America.
So, the LED converts free heat along with the electrical energy into light. So I suppose, yes, if you had a closed, dark room, and you made an array of these lights, and you plugged them into a power source, and you spotted them on a PVC with over 50% efficiency, and you routed that PVC's output back into the LEDs, you would have yourself an ongoing power source that would actually increase in power until you tapped some of it out for safety. Which you could then use! Furthermore, the meanwhile, the LEDs thermocoupling the heat energy along with the joules of electrical energy and transforming it all into light are steadily making the entire environment cooler.
#1:) higher efficiency
#2:) cooler house
That means you are also cooling your house while you are generating perpetual motion! This is good because you will have to keep your house heated in order to continue to supply energy to the system you have created. The sun is the most obvious source! If you switch from tinfoil to copper foil and cook the outside of it twice before wearing it, your foil hat can act as a sun magnet!
At any rate, this all seems like an argument for further complicating a field of study I have luckily not yet spent college money on. They will end up having to either re-do their study with a mind toward clarifying where energies are coming from and how they're measurable, or physics is going to have to come up with a yet even more complex unit of measurement (oh, great) in order to avoid further claims such as these.
"Stratigraphically the origin of agriculture and thermonuclear destruction will appear essentially simultaneous" -- Lee
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.
The only problem is what to do with all the excess electricity these things will produce.
I'd hardly call that a problem.
"If a nation expects to be ignorant and free in a state of civilization, it expects what never was and never will be."
As I understand it, yes. But you would have to use every square inch of the skin of your house as a light output, and may even need to suspend it high enough in the atmosphere so that light emitted from the bottom of your house did not reflect off the earth back up to your house, thus warming it. I doubt that it could ever cool your house by even a millionth of a degree (either C or F), and all hopes are gone if you conducted the test during the daytime.
Buying and running an air conditioner is still your best choice.
Free unix account: freeshell.org
... that adding LEDs to stuff made it cooler.
Collector's Edition
To be fair, you pretty much had to miss about an entire week of news around the internet to have missed out on the loose cable story. People tend to take their light-speed limits pretty seriously these days.
in your case, will cool your case.
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A true Light Beer
How many orders of magnitude is 'a bit' in your world?
That would be one order of magnitude, in base 2.
I'm a good cook. I'm a fantastic eater. - Steven Brust
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).
Monster Cable TOSLink?
scientific papers?
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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.
Another addition to laws's of thermodynamics?
First there were:
1 - You can't get something for nothing.
2 - you can't even break even.
Then they added: 0 - Cold trumps hot.
Now what? -1 - unless it's an LED?
(TIC)
A) you would just need 40% efficient panels.
B) taking heat out of the atmosphere would be fine.
Of course, if we could get 40% efficient panels, that would be a world class break through.
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photocell...very sensitive to infrared light...The infrared heat hits the photocell
Infrared is not heat. You were right the first time.
I see a lot of joke comments talking about hooking this LED, that is getting a significant amount of high entropy heat and turning it into higher entropy light, to a photoelectric cell. I can understand the heat to light in terms of thermodynamics, but assuming an efficient enough photoelectric cell isn't turning high entropy energy into low entropy usable electrons "cheating?" Could someone tell me why this wouldn't work in the real world (I just assume it can't)? Do photovolts not work at that energy level? Would the energy be so low that the photovolt would simply loose the electrons to signal loss before generation enough of a voltage gap (though this would be fixable with well insulated micro circuitry one would think)? The explanation of turning heat into light thermodynamically seems acceptable to me, but I do not understand where the loss would come when converting said light back into electrons.
You'll hit one point twenty one gigawatts in no time.
Let me know when you get an 80% efficient solar cell.
NM, I;'l find out when you become the richest man no the planet.
Man, 800watts from 1 sqr meter of light. Man, that would solve, at the very least, the day time needs of every home owner there is.
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all of them.
The Kruger Dunning explains most post on
You'll have to duct tape your breakers open! Again.
people thought the transistor was a perpetual motion machine.
So, it it seems like a perpetual motion machine, it's because you are clueless, or they are lying.
Shame there isn't some article about it to find out who is wrong..
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well, except for the increase in CO2 and other chemicals that can make the planet inhospitable to humans.
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On a larger scale could a smaller amount of electricity(relative to current cooling/lighting costs) and a hot server room create a lighted, cooler server room? Would a hot attic in the summertime save me $ by channeling light into my home AND cooling my crawlspace? Could this cool my tower and light my office simultaneously? Sounds theoretically doable(based on TFA), but...could it scale up and preserve efficiency?
Imagination drew in bold strokes, instantly serving hopes and fears, while knowledge advanced by slow increments...
If this result could occur at useful energy levels, it would be revolutionary. But very likely it's just an interesting anomaly that occurs at very low energy levels. My guess is that at such low energy levels, the disordered nature of the energy in the ambient heat doesn't come into play, but at higher energy levels it would. There simply wouldn't be enough heat energy in the surrounding environment to create the same effect at higher energy levels. Please let me know if there's a flaw in my undertsanding of the science.
It's not a marketing scam, a heat pump is used in the same applications as a heater would be used, it is comparing efficiency to a heater
Snowden and Manning are heroes.
Voltage-enhanced thermoluminescence
Set your phasers on "funky"!
David Brin wrote that book, not Robert L. Forward. Correct that entry in your neural net.
--PM
An air conditioner is a heat pump. So, you say that heat pumps are more efficient at cooling than heat pumps. That makes no sense.
A successful API design takes a mixture of software design and pedagogy.
So I can get cool air and light on hot summer nights?
According this this logic my fridge is also greater than 100% efficient, and breaks the 1st law of thermodynamics. Turned on again after a defrost, it generates more heat than the electical energy it consumes from the socket. (If you ignore the cooling inside the freezer)
Yes, I'm sure that someone quoting the simpsons thought they were being original.
Yep, each time a diode on Earth draws > %100 efficiency the life force is sucked from a faery in a parallel dimension!
(If at first you don't succeed, do it different next time!)
Nonsense. Imagine, that your higher entropy incoherent electromagnetic radiation is absorbed back by matter and becomes heat again. In your model entropy will go down. Besides, black body radiation is the EM incoherent light of maximum entropy which is in thermal equilibrium with matter. LED light spectrum is almost monochromatic and has lower entropy than black-body radiation at the same temperature.
Is this some form of Maxwell's demon, 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.
According to TFA, the LED outputs 230% of the input energy by "stealing energy (in the form of heat) from its environment" - in other words, that LED device has a side effect of cooling things down
Will LED become next generation of cooling appliance?
BTW, I remember, about 10 years ago, /. had a post about a certain chip that can cool things down using "quantum effect" or something, that a British firm had a patent on it
I can't find that article right now, but I suspect what happened there and what is happening to the MIT experiment on LED may be similar
Muchas Gracias, Señor Edward Snowden !
In theory.
--
I'm out of my mind right now, but feel free to leave a message.....
Are you out of your mind?
If you took the screen and the crap out of an iPad 4 I bet you could mount a lot of LEDs in the good part. That would improve it 230% and be a BRIGHT idea for those who "thunk different".
I'll write an instructable !
*Repent!Quit Your Job!Slack Off!The World Ends Tomorrow and You May Die!
I've just realized something remarkable: the slashdot comments are less stupid than those in the surrounding environment, where people are having trouble grasping that the 2nd Law of Thermodynamics is the issue, not the 1st.
Now, if only we could harness this gradient of stupidity.
Sounds like more thermal emissions than operation of a diode.
"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.
I've fallen off your lawn, and I can't get up.
What an intriguing idea. A light that actually consumes heat and emits it as light. One energy source is as good as another -- I have to wonder if there are many other areas of research where we've focused on electricity as the power for a device when there might be alternative transforms from other sources available.
In short, no, it doesn't sound like they're breaking any laws of thermodynamics or energy balance equations. Instead, they're just using an unusual source to boost the inputs: heat.
I do not fail; I succeed at finding out what does not work.
Foolish science it is
Or worse, good basic semiconductor research overhyped into a new kind of physics that brakes all of our expectations..
New physics my ass.
smaddox is basically right, but so is quarterbuck: blackbody radiation is a bad comparison, the photons' energy isn't thermal but determined by the band gap, the color the led was designed for. A better comparison would be a crystal that gets heated up: If an electron that was captured in an excited state drops down it releases a photon. Except that they now also got a pump mechanism to lift the electrons, like in a laser. The energy for that lift comes from heating the diode. At 130C the probability would be pretty small, and I guess that's where their pico-current comes in: Creating regions, where a thermally excited electron can make it to the upper band.
Overall, it is kind of a heat driven led with electrical control.
You could probably also speculate about tunneling or electron-phonon resonance effects.
But calling it 230% efficient? That's like me calling a npn transistor 10,000% efficient after comparing I(BE) to I(CE). Don't get me wrong, they used thermal energy to pump photons, that is cool. But their hype is something neither I nor Einstein would have ever done, just plain assholery.
DNRTFA. Anything with the tagline "Is it true that 230% efficient LEDs seem to violate first law of thermodynamics?" automatically gets a caustic answer from me, because I don't have to read the article to know the answer. Whoosh!
Don't you know, the first law of Thermodynamics is: We don't talk about thermodynamics!
130% of it is coming from the neighbor's outlets. Very sneaky, you cheapskates.
Although were not talking a lot of power it might be something if you could get the components small and efficient enough such that for each combo led+photocell you could power at least 1.5 other units. Not base 2 but still significant if you can get a billion such micro units working.
A think there are more efficient ways to harvest power from heat. I'm still waiting for process with micro rectifiers for converting heat vibrations directly to electricity.
It's not a marketing scam, a heat pump is used in the same applications as a heater would be used, it is comparing efficiency to a heater
It is comparing efficiency to a heater, for the purpose of...? Anyone? Bueller? For the purpose of getting you to buy the heat pump. In other words, marketing.
When our name is on the back of your car, we're behind you all the way!
Hmm, it may be used as optical pumping for a laser!
A successful API design takes a mixture of software design and pedagogy.
"Perpetual motion describes hypothetical machines that operate or produce useful work indefinitely and, more generally, hypothetical machines that produce more work or energy than they consume, whether they might operate indefinitely or not." link
AccountKiller
Operational amplifiers do it all of the time.
Yes but the point is it's a valid comparison. What you care about as the purchaser of a heater is how much it is going to cost you in electricity for a given amount of heating. You, the customer, don't give a fuck about the 'cost' in lost heat from the outside. Other than if you become curios as to whether the heat pump's claimed efficiency (which is correct for what it is talking about) is also claiming a violation of the 1st law in which case the answer is no.
The enemies of Democracy are
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True I guess I should have been a little more clear in differentiating the types of heat pumps. Would saying that ground source heat pumps are more efficient than the standard AC unit (the ones with the compressor and giant radiator outside) be better?
Time to offend someone
The laws of thermodynamics say you can't simply extract energy from heat. You have to extract energy from a temperature difference. Seemingly this research goes against that, so I suspect there has been some error in the measurement somewhere until I see further evidence.
(I suspect the error in this research is the method used to keep the LED at 135 C. If the leads are connected to a circuit which is cooler, they might cause one side of the silicon in the LED to be slightly cooler than the rest. If that were the case, it would form a peltier effect unit, which would drive the LED even without any electrical energy.)
Are they called Monster Cables by any chance?
This is a Light emitting diode operataing in the IR spectra, if it has properties that allows it to do sorting (=dioding) on thermal (IR) photones - we are on to something very intresting. Making the high energy photones go to one side and hence getting a cold side and a warm one? Airconditioning and heating without running up the electrical bill or burning fossile fuel... Next question is if this can run without the input of electricity? and if the ammounts of energy are intresting or just a novelty?
They are not inherently any more efficient. With a ground source your heat sink is cooler, that makes it more efficient by definition, but how is an AC to blame here? If you fed your AC unit with similarly cold air, the thermodynamic efficiency would be matched. Such an AC unit would still be somewhat less efficient overall (not thermodynamically) because the fan blowing the air over the exterior heat exchanger dissipates more energy than an antifreeze pump, per unit of heat exchanged.
A successful API design takes a mixture of software design and pedagogy.