3 ms·

Comparing theoretical efficiency of new design for incandescent lighting with commercially available LEDs does not make sense, as theoretical efficiency of whi

by xyzzyz 10y ago

Comparing theoretical efficiency of new design for incandescent lighting with commercially available LEDs does not make sense, as theoretical efficiency of white LEDs is also around 40%. I'll consider incandescents once the efficiency of commercially available ones reaches the efficiency of commercially available leds. I bet $100 that it will not happen in next 10 years.

nkurz 10y ago
Comparing theoretical efficiency of new design for incandescent lighting with commercially available LEDs does not make sense Yes. They say they are currently at 6% efficiency, which is better than the worst CFL's and LED's, but far from matching the best. as theoretical efficiency of white LEDs is also around 40% Yes, although one should probably include the power supply. I think the advantage of the incandescent approach is that there are no losses here. I'll consider incandescents once the efficiency of commercially available ones reaches the efficiency of commercially available leds. Sure, sounds wise. Light quality and longevity might be factors too. But what does this have to do with the claim that the article says "LEDs are only twice as efficient as traditional bulbs"? The article can be read as claiming that the worst commercially available LED's are about 2x the efficiency of the best incandescents, and perhaps this is false, but I don't see this as reason to discount the rest of the details. Here's earlier discussion of this approach, which includes a link to the actual paper: https://news.ycombinator.com/item?id=11771001 https://news.ycombinator.com/item?id=11771001
ryao 10y ago
The theoretical efficiency of LEDs is definitely not 40%. LED efficiency has been measured to be 230% with 30 picowatt power consumption: https://www.google.com/amp/phys.org/news/2012-03-efficiency.amp https://www.google.com/amp/phys.org/news/2012-03-efficiency....
- nkurz 10y ago
  Their claimed efficiency is only sort of true, in that it's measuring the electrical input while ignoring the external heat also used to run the light. By similar logic, one could say that a steam engine running in a very hot room is also over 100% efficient. Also, the "theoretical efficiency of LEDs" is a very different number than the "theoretical efficiency of white LEDs". I think when talking about white LEDs, they are assuming a monochromatic LED pumping a phosphor. But while it's not that practical, in that it's limited to picowatts (10^-12 watts), it is interesting nonetheless. Another similarly surprising example is that the theoretical maximum efficiency of some fuel cells also exceeds 100%, for similar reasons of extracting heat from the environment.

by xyzzyz 10y ago

nkurz 10y ago

Comparing theoretical efficiency of new design for incandescent lighting with commercially available LEDs does not make sense Yes. They say they are currently at 6% efficiency, which is better than the worst CFL's and LED's, but far from matching the best. as theoretical efficiency of white LEDs is also around 40% Yes, although one should probably include the power supply. I think the advantage of the incandescent approach is that there are no losses here. I'll consider incandescents once the efficiency of commercially available ones reaches the efficiency of commercially available leds. Sure, sounds wise. Light quality and longevity might be factors too. But what does this have to do with the claim that the article says "LEDs are only twice as efficient as traditional bulbs"? The article can be read as claiming that the worst commercially available LED's are about 2x the efficiency of the best incandescents, and perhaps this is false, but I don't see this as reason to discount the rest of the details. Here's earlier discussion of this approach, which includes a link to the actual paper: https://news.ycombinator.com/item?id=11771001 https://news.ycombinator.com/item?id=11771001

ryao 10y ago

The theoretical efficiency of LEDs is definitely not 40%. LED efficiency has been measured to be 230% with 30 picowatt power consumption: https://www.google.com/amp/phys.org/news/2012-03-efficiency.amp https://www.google.com/amp/phys.org/news/2012-03-efficiency....

nkurz 10y ago
Their claimed efficiency is only sort of true, in that it's measuring the electrical input while ignoring the external heat also used to run the light. By similar logic, one could say that a steam engine running in a very hot room is also over 100% efficient. Also, the "theoretical efficiency of LEDs" is a very different number than the "theoretical efficiency of white LEDs". I think when talking about white LEDs, they are assuming a monochromatic LED pumping a phosphor. But while it's not that practical, in that it's limited to picowatts (10^-12 watts), it is interesting nonetheless. Another similarly surprising example is that the theoretical maximum efficiency of some fuel cells also exceeds 100%, for similar reasons of extracting heat from the environment.