Solar energy that doesn't block the view(sciencedaily.com)
sciencedaily.com
Solar energy that doesn't block the view
http://www.sciencedaily.com/releases/2014/08/140819200219.htm
4 comments
Care to elaborate on the other pv-related window technologies? I'm curious.
Last decade I followed news of XsunX and their Power Glass ... and it was like following news of flying cars, or returning to the moon: a continuous parade of stories, every single one saying "we're almost there, next year we'll really have it ready!"
The concept of "Power Glass" was similar to the article here; the glass had tiny PV technology buried inside, with the idea that skyscrapers with their glass facades could generate their own power, along with any other building using lots of glass in its skin.
I see XsunX no longer mentions Power Glass on their website [1]. Now it looks like any PV manufacturer. You have to go back 8 years in the Internet Archive to see it [2]. They were sure proud of this revolutionary technology ... 8 years ago.
Oh well. At least flying cars are showing [3] progress [4].
[1] http://www.xsunx.com/
[2] https://web.archive.org/web/20060705005757/http://www.xsunx....
[3] http://www.terrafugia.com/
[4] http://mavericklsa.com/
Last decade I followed news of XsunX and their Power Glass ... and it was like following news of flying cars, or returning to the moon: a continuous parade of stories, every single one saying "we're almost there, next year we'll really have it ready!"
The concept of "Power Glass" was similar to the article here; the glass had tiny PV technology buried inside, with the idea that skyscrapers with their glass facades could generate their own power, along with any other building using lots of glass in its skin.
I see XsunX no longer mentions Power Glass on their website [1]. Now it looks like any PV manufacturer. You have to go back 8 years in the Internet Archive to see it [2]. They were sure proud of this revolutionary technology ... 8 years ago.
Oh well. At least flying cars are showing [3] progress [4].
[1] http://www.xsunx.com/
[2] https://web.archive.org/web/20060705005757/http://www.xsunx....
[3] http://www.terrafugia.com/
[4] http://mavericklsa.com/
Even though to the uninitiated it sounds like a no-brainer to cover windows with solar panels, it turns out that what makes a solar panel effective is that it converts the light to electricity and only lets through what it can't convert (which, sadly, tends to be what you can't see).
Windows are useful because they let light through. Solar panels are useful because they don't.
If you ended up with some sort of hybrid that let 50% of the visible through and absorbed 50% of the balance, it would not be a very good window (too dim or obstructed), and it would cost at least double what a comparable solar panel would cost (per watt). You'd also take some hits to aesthetics and efficiency (humans want reflective coatings on smooth window glass, solar cells want antireflective coatings on textured low-iron glass).
Wiring up the windows would likewise add to the installation cost. Solar panels produce their rated power facing somewhere between up and south (in the northern hemisphere), and building windows almost never face in that direction, making for an ever bigger hit to performance.
Installing panels on buildings can be a good idea, but not where the windows go. Rooftops and south-facing walls are about it.
Windows are useful because they let light through. Solar panels are useful because they don't.
If you ended up with some sort of hybrid that let 50% of the visible through and absorbed 50% of the balance, it would not be a very good window (too dim or obstructed), and it would cost at least double what a comparable solar panel would cost (per watt). You'd also take some hits to aesthetics and efficiency (humans want reflective coatings on smooth window glass, solar cells want antireflective coatings on textured low-iron glass).
Wiring up the windows would likewise add to the installation cost. Solar panels produce their rated power facing somewhere between up and south (in the northern hemisphere), and building windows almost never face in that direction, making for an ever bigger hit to performance.
Installing panels on buildings can be a good idea, but not where the windows go. Rooftops and south-facing walls are about it.
>Lunt said more work is needed in order to improve its energy-producing efficiency. Currently it is able to produce a solar conversion efficiency close to 1 percent, but noted they aim to reach efficiencies beyond 5 percent when fully optimized. The best colored LSC has an efficiency of around 7 percent.
By contrast, conventional rooftop solar is about 18-23% efficient and you need a whole roof of those (often more) to power your house.
I don't think this would provide more than a tiny trickle of electricity, and probably at quite high cost.
By contrast, conventional rooftop solar is about 18-23% efficient and you need a whole roof of those (often more) to power your house.
I don't think this would provide more than a tiny trickle of electricity, and probably at quite high cost.
That percentage will probably be even worse than that, since windows aren't at the best angle or position for solar panels.
You guys are missing the fact that current windows are losing all of the energy incident on them. 5% is infinitely better than 0%.
It's only infinitely better if the cost of installing these systems is zero. It isn't zero.
Just about the only situation it would make economic sense to do this would be if it were almost the same cost of regular glass, and you already had a PV system set up with virtually all the wiring & inverters necessary already in place (these are a significant cost - roughly 50% of a regular PV installation).
Otherwise the cost simply wouldn't make it worthwhile.
Just about the only situation it would make economic sense to do this would be if it were almost the same cost of regular glass, and you already had a PV system set up with virtually all the wiring & inverters necessary already in place (these are a significant cost - roughly 50% of a regular PV installation).
Otherwise the cost simply wouldn't make it worthwhile.
Would be very cool to use on a skylight. It would generate electricity and heat your home! Put some blinds on the inside and block the light in the summer time.
When there's a lot of sun your home needs cooling, when it's cold there is not much sun.
If you filter out infrared light before it comes through the window, would that help your air conditioning a significant amount?
It would help, no doubt, even if I cannot estimate how much.
OTOH, it would help as well if windows did not filter IR radiation. You know, a greenhouse works because glass is transparent to visible and near IR radiation, but is quite opaque to far IR. Visible light is the peak of the spectrum of solar e.m. radiation and its frequency is proportional to the temperature of the sun photosphere (~6000 K). Visible and near IR radiations traverse the glass, gets absorbed by objects and heat them. Part of this heat will be re-emitted as far IR radiation, with a frequency proportional to room temperature (~300 K), which is 20 times smaller than visible light. This factor 20 is enough for the glass to turn from transparent to opaque. That's why you can have a greenhouse, or simply a car with its windows closed, get hotter than the surrounding atmosphere.
OTOH, it would help as well if windows did not filter IR radiation. You know, a greenhouse works because glass is transparent to visible and near IR radiation, but is quite opaque to far IR. Visible light is the peak of the spectrum of solar e.m. radiation and its frequency is proportional to the temperature of the sun photosphere (~6000 K). Visible and near IR radiations traverse the glass, gets absorbed by objects and heat them. Part of this heat will be re-emitted as far IR radiation, with a frequency proportional to room temperature (~300 K), which is 20 times smaller than visible light. This factor 20 is enough for the glass to turn from transparent to opaque. That's why you can have a greenhouse, or simply a car with its windows closed, get hotter than the surrounding atmosphere.
Actually, greenhouses work because they let the sun in but prevent convection from cooling the heated surfaces. The stuff inside would need to get pretty hot to put out enough IR to make much of a difference.
https://en.wikipedia.org/wiki/Greenhouse_effect#Real_greenho...
https://en.wikipedia.org/wiki/Greenhouse_effect#Real_greenho...
This doesn't negate what I said. Preventing convection means that hot air stays inside instead of being dispersed. But hot air does emit IR radiation, and if that radiation could escape the air would get fresher.
In the wiki link that I posted an experiment is mentioned where they used rock salt instead of glass to build a greenhouse. Rock salt is IR transparent, yet the greenhouse got to nearly the same temperature. Hence IR transparency is mostly irrelevant.
Thanks for the link, that's interesting. But, please, have a look on this site as well: http://www.drroyspencer.com.
Infrared, on the other hand, has some power production capability (though visible contains a much better resource). Even though we may only be looking at 0.3V (high wavelengths have low voltages), we might be getting a few amps with a square foot of this material.
Makes a lot more sense than other PV-related window technologies. They're going to have to figure out how to cool the concentrator cells lest they cause adjacent construction materials to catch fire with how hot they run. (I^2R losses mean that these high current cells will be dumping a lot of heat per watt generated).