kisai Posted March 9, 2012 Posted March 9, 2012 Ultra-efficient LED puts out more power than is pumped in Even though the amount of thermal energy leeched from its environment is miniscule, I feel that this is a triumph of engineering and a step towards converting some of the waste heat using semiconductor architecture.
md65536 Posted March 9, 2012 Posted March 9, 2012 Ultra-efficient LED puts out more power than is pumped in Even though the amount of thermal energy leeched from its environment is miniscule, I feel that this is a triumph of engineering and a step towards converting some of the waste heat using semiconductor architecture. Is the effect only present for a short time after they reduce the power? How much of the heat that gets converted into light, comes from heating up the LED while running with higher energy consumption, earlier? Obviously, if the LED cools itself and/or immediate environment, then the amount of energy it can draw from the environment must diminish (it can't keep making the environment colder without outside energy coming in to replace it). I don't even know if the energy comes from a relatively hot LED cooling to ambient temperature, or if it actually draws energy from its surroundings, cooling them below ambient. The way it's written I suspect the effect only happens while reducing energy input, rather than a sustained effect at a fixed energy input. I think it is similar to saying that the pedalling efficiency of a bike is > 100% when biking down a mountain... but you still have to get up the mountain first.
swansont Posted March 10, 2012 Posted March 10, 2012 It's a heat engine. You generally don't describe efficiency in this way, since you can move energy around at the expense of a smaller amount of energy. That's why coefficient of performance is used, and can be significantly greater than 1. 1
Recommended Posts