LED's Efficiency Exceeds 100%

newfocogi · 2025-03-20T16:37:18 1742488638

Wait, where is the energy beyond the electricity coming from? Is it drawing heat from the environment, hence the references to heat pumps?

lordnacho · 2025-03-20T16:58:19 1742489899

I think it is analogous to setting your tap to a teeny tiny amount of "on," and in doing so you entrain the existing droplets in your tap to fall out.

vFunct · 2025-03-20T16:42:05 1742488925

Yep. It's taking environmental heat energy alongside electricity and converting to light.

MrMid · 2025-03-20T16:41:34 1742488894

Exactly, it consumes heat.

> ... took advantage of small amounts of excess heat to emit more power than consumed.

Analemma_ · 2025-03-20T16:42:19 1742488939

Yes, it's drawing heat from the environment: the diode itself gets cooler as it emits light, and presumably at some point there's no more available energy in this way and so efficiency goes back below 100%

thmsths · 2025-03-20T16:49:47 1742489387

Which is still amazing. An issue with high power LED is cooling. If this can be turned into a product, it solves the issue in the best possible way.

MrMid · 2025-03-20T16:42:08 1742488928

[2012]

ewzimm · 2025-03-20T16:39:44 1742488784

Now we just need a perpetual entropy-powered photo-electric computer that uses a contained low-light LED array for internal data transfer, storage, and computation mechanisms as well as a power source. Okay, maybe not that, but this could lead to some interesting applications.

flanked-evergl · 2025-03-20T16:57:34 1742489854

Nope. The headline is categorically false. A LED's efficiency does not exceed 100%. Science journalism is an absolute dumpster fire.

bell-cot · 2025-03-20T16:39:35 1742488775

And another headline from the Dept. of Sensationally Miss-Represented Scientific Results.

Vs. reality - the ">100%" is at nano-power levels, and is powered by the LED's temperature falling.

So, while the underlying effect might have some practical application, this is ">100% efficiency" in the same sense that "turned off the LED's electric power, set it on fire, then measured the fire's light output" is ">100% efficiency".

proaralyst · 2025-03-20T16:56:28 1742489788

This feels similar to heat pumps being >100% efficient though? Perhaps a less misleading headline would be 'Very low-power LEDs also convert heat to light'

nyeah · 2025-03-20T16:52:24 1742489544

' this is ">100% efficiency" in the same sense that "turned off the LED's electric power, set it on fire, then measured the fire's light output" is ">100% efficiency".'

It's absolutely a misleading headline. But that last part is a little harsh. The power is awfully low, but someday a partly-heat-powered LED might not be 100% useless.

josefritzishere · 2025-03-20T16:39:03 1742488743

This would tend to indict an artifact in measurement rather than an indictment of the 2nd law of thermodynamics.

toast0 · 2025-03-20T16:49:48 1742489388

It's a well reported effect, LEDs can emit light using electrical and heat energy. That gives better than 1 efficiency of light from electric input. Not a violation of the 2nd law, just a way to beam heat out of an environment.

Power levels are low though, so I haven't seen any reports of applications.

Retr0id · 2025-03-20T16:49:47 1742489387

A heat pump can operate at ">100% efficiency" without breaking the laws of thermodynamics, the trick is that its moving the thermal energy around rather than merely "producing" it. It wouldn't surprise me if the LED is doing something similar.

edu · 2025-03-20T16:45:22 1742489122

From the article, it seems that the extra energy is obtained from heat in the environment around the LED.

zamadatix · 2025-03-20T16:47:46 1742489266

The article was very clear the efficiency percentage is in regards to electrical input to light output, not energy input to energy output, and the source of this is explained as well (the LED consumed additional heat energy in this period).

tomp · 2025-03-20T16:51:50 1742489510

perpetuum mobile anyone?

LED produces light 230% of power put in, convert that back to electricity with PV (47.6% efficiency) to get 109.48% of electricity you put in, while conveniently cooling the surroundings.

email me to invest in my startup!

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