Skip to content

Comment on LED's efficiency exceeds 100%

Comments

Can someone explain how this makes sense in terms of conservation of energy?

Their "efficiency" is light output vs electrical input. The result is actually that it starts converting heat as well as electricity into light. So you get more energy in light out than you put electricity in. You just put more energy in than electricity.

Vaguely like a heat pump - electrical energy stimulates conversion of thermal energy to light. So instead of using electricity to produce light and heat, LED uses electricity and heat to produce light.

well, they didn't take into account the energy produced by the ambient temperature (the exact temperature was not mentioned in the article, and the paper is behind a paywall, but they do say it was rather high)

> [it] 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.

It'd be nice to know if this meant 'inside an oven' ambient heat, or Houston/Singapore/Riyadh levels of heat.

edit: I see from mikeknoop's comment they mean inside-an-oven levels: 135'C/275'F.

AboutSource Built by g1lg1l

Hackerly is an independent reader for Hacker News, built on the public HN API. Not affiliated with Y Combinator.