What do you think of this?

Bogus. They never mention efficiency. Or lifetime.

It's gotta be more efficient than regular tinted windows, if your goal it to make it darker indoors.

But yeah figures for absorbed vs converted vs reflected would be useful, worse case could be (in comparison to reflective coatings) air con goes up by more than energy produced.

I didn't see any reference to power output per meter or price per kilowatt used for their calculations. Just wishfull sales bable.

Cheers

Aside from how good or otherwise it is, windows may not be particularly high on the ListOfThngsToCoverWithSolarCells.

Not a thought I would share. We just spent about $1000 covering our windows with a film that blocks UV. If we could have got solar cells to do the same job and generate power at the same time, we'd probably have gone for that.

The pictu8res that we want to protect from the UV aren't all that special, but we like them.

I skimmed the article, but did not see anything that suggested that the solar cells reduce the UV transmission. They did stress that the coating did not block visible light.

Dan

As others have noted, it's all sales babble without a shred of real information.

But my first reaction was to wonder how long it would take ordinary window washing to destroy the solar effect. We have this done at least once a year, and it makes a big difference in clarity.

Joe Gwinn

Joe Gwinn wrote in news:310820140910108745% snipped-for-privacy@comcast.net:

They claim to be using organic solar cells. I wonder what the long term efficiency vs lifespan graph looks like? I suspect they are likely to degrade fairly rapidly in a similar manner to OLEDs. A crystalline Silicon PV cell that is properly hermetically sealed has negligable loss of output in a decade. (Assuming its enclosure window is kept clean and scratch free.)

dows with a film that blocks UV. If we could have got solar cells to do the same job and generate power at the same time, we'd probably have gone for that.

olar cells reduce the UV transmission. They did stress that the coating di d not block visible light.

If the coating generates electric power, it has to absorb photons. If it do esn't absorb visible light, it has to absorb UV. In fact it probably also a bsorbs an appreciable fraction of the blue end of the solar spectrum, other wise it wouldn't collect enough photons to generate any significant power.

You need to recall Einstein's famous 1905 paper on the photo-electric effec t.

Don't forget the IR end of the spectrum. Silicon is mostly sensitive there, and peaks at 1000 nm.

As for the organic film, we don't know what it is, or what its spectral response is.

Joe Gwinn

Yes, with that paper in mind I would note that any energy above the activation energy for the release of an electron is wasted. When you talk about only blue light or shorter wavelength producing electrons you are thinking of silicon which has a significant band gap. I have not looked into the organic photocells, but if they have a lower band gap they can produce electrons with longer wavelengths. Remember that visible light does not cover a wide range of wavelengths, less than a range of 2:1.

There is a lot about this design that is not explained and from the web pages it appears that they are still very much in the development stage. But I see nothing that says the product is 100% transparent. They say, "See-through, with high level of ?visible light transmission?". To me that just says they capture a portion of the light, not all of it. From the way they talk about harvesting indirect light being useful I expect this product will be a very low cost thing much cheaper than silicon solar cells. So even with low efficiencies it may be cost effective.

As to the longevity of the film, hard to say, but I expect the layer will not be on the outside of the glass, but rather on the inside of double glazed windows. They do tout how thin the layer is so it has got to be very fragile if exposed to any abrasion.

What I find more interesting is their vehicle motion energy harvesting. Installation at exit ramps and other locations where the vehicles will be slowing down is an interesting idea. Not sure if there are enough locations like that to make it worthwhile but I'd take another look when they have more info.

If you found a window material that transmits UV, please let me know so we can make our fortune!

Quartz.

Ordinary window glass will transmit enough uv to fade colors. Low E glass blocks uv and infrared light.

Dan