4 ms·

Does that 'wear-out' the panel quicker? I assume that more light focused can mean more heat. I'm told people try something similar with mirrors now but it tends

Does that 'wear-out' the panel quicker? I assume that more light focused can mean more heat. I'm told people try something similar with mirrors now but it tends to not work out well for the panel itself.

dogma1138 11y ago
Mirros are only used for thermal solar applications where one heats up oil or melts salts to produce steam to power a normal power turbine. https://en.wikipedia.org/wiki/Solar_thermal_energy https://en.wikipedia.org/wiki/Solar_thermal_energy For photovoltaics you do not want to focus the light for many reasons the cell has a cap per surface area that it can produce, you don't want voltage spikes across the subcells (if it exceeds the overall limits of the cell it will damage it), it wears out the cell, and the cell efficiency drops as the temperature increases.
- mikeash 11y ago
  Mirrors and lenses can be used with photovoltaics as well: https://en.wikipedia.org/wiki/Concentrator_photovoltaics https://en.wikipedia.org/wiki/Concentrator_photovoltaics I know pretty much nothing about it besides the fact that it exists, though.
- kyzyl 11y ago
  The power coming from the sun is approximately constant. The power hitting any given spot on the planet is far from constant due to weather, day/night cycles and seasonal shifts. For a given solar installation, there might be a time where the ambient intensity (power per unit area) of the light has the cells biased just-so, converting energy at a near ideal efficiency. Of course then the conditions change and this isn't the case any more. When you run into that scenario, i.e. the sun has moved a bit, it becomes very useful to have some kind of mirror or lens to increase the intensity by collecting more of the light and concentrating it to a smaller area, thus bringing you closer to your ideal operating point. You're correct that at some point you get undesirable transients, or you just melt your cell. I do that by accident more often than I'd like, by shining infrared lasers at a photo diodes while forgetting that I've left a microscope objective in front. Expensive mistakes. Now re: the article, if you ask me the really interesting thing here isn't being able to focus light to really small areas per se, but that they've broken the diffraction limit. This means you can form an image of an object that is smaller than a half-wavelength of light. For e.g. red light, that means you can take a picture, an optical picture, of something like, say, a mosfet on a chip. Or a virus. That's quite something. I'll note however that I could foresee (read: speculate) a scenario where having such a tiny focus, like the solar cell scenario, could invoke a quantum mechanical effect in some special material whereby the light coupling becomes much greater, thus increasing efficiency or something. But that's just science fiction as far as I know. PS: Sorry if this is patronizing. I know nothing about my audience ;-)

dogma1138 11y ago

Mirros are only used for thermal solar applications where one heats up oil or melts salts to produce steam to power a normal power turbine. https://en.wikipedia.org/wiki/Solar_thermal_energy https://en.wikipedia.org/wiki/Solar_thermal_energy For photovoltaics you do not want to focus the light for many reasons the cell has a cap per surface area that it can produce, you don't want voltage spikes across the subcells (if it exceeds the overall limits of the cell it will damage it), it wears out the cell, and the cell efficiency drops as the temperature increases.

mikeash 11y ago
Mirrors and lenses can be used with photovoltaics as well: https://en.wikipedia.org/wiki/Concentrator_photovoltaics https://en.wikipedia.org/wiki/Concentrator_photovoltaics I know pretty much nothing about it besides the fact that it exists, though.
kyzyl 11y ago
The power coming from the sun is approximately constant. The power hitting any given spot on the planet is far from constant due to weather, day/night cycles and seasonal shifts. For a given solar installation, there might be a time where the ambient intensity (power per unit area) of the light has the cells biased just-so, converting energy at a near ideal efficiency. Of course then the conditions change and this isn't the case any more. When you run into that scenario, i.e. the sun has moved a bit, it becomes very useful to have some kind of mirror or lens to increase the intensity by collecting more of the light and concentrating it to a smaller area, thus bringing you closer to your ideal operating point. You're correct that at some point you get undesirable transients, or you just melt your cell. I do that by accident more often than I'd like, by shining infrared lasers at a photo diodes while forgetting that I've left a microscope objective in front. Expensive mistakes. Now re: the article, if you ask me the really interesting thing here isn't being able to focus light to really small areas per se, but that they've broken the diffraction limit. This means you can form an image of an object that is smaller than a half-wavelength of light. For e.g. red light, that means you can take a picture, an optical picture, of something like, say, a mosfet on a chip. Or a virus. That's quite something. I'll note however that I could foresee (read: speculate) a scenario where having such a tiny focus, like the solar cell scenario, could invoke a quantum mechanical effect in some special material whereby the light coupling becomes much greater, thus increasing efficiency or something. But that's just science fiction as far as I know. PS: Sorry if this is patronizing. I know nothing about my audience ;-)