Posted on 10/30/2009 7:11:10 AM PDT by Reaganesque
Now this IS cool.
Arrange cheap, but low-efficiency, solar cells around an optical fiber.
Result would be high efficiency on the surface exposed to sunlight.
Now this IS cool.
Arrange cheap, but low-efficiency, solar cells around an optical fiber.
Result would be high efficiency on the surface exposed to sunlight.
When designing optical fibers for telecommunications engineers try to avoid light "bouncing around" inside the fiber because it causes loss in amplitude of the signal beig transmitted down the fiber. Leave it to my homies at my Alma Mater to come up with a way to turn loss into gain.....again.
You are still going to need significant square footage, to get power. The 24/7, day-night mean for the CONUS is 7 Watts per square foot (averages Phoenix and Chicago, winter-summer, etc) so if you want a kilowatt you’ll need 150 square feet, more or less, even with 80% efficiency.
Note also that the comparison is between zinc oxide planar cells and zinc nanowire cells. What’s the comparison between the nanowire cells and Cu-Si cells or crystalline Si cells?
How much would a million-square-foot array of the new technology cost?
As an investor I read these periodic announcements with caution. Go back ten years and look up how many of these incredible breakthroughs actually worked, in practical terms.
And if you go back to 1957, we should have moon colonies, flying cars, robot lawn mowers (we have robot carpet vacs now), solar power, nuclear power too cheap to meter, and so forth.
“Result would be high efficiency on the surface exposed to sunlight.”
That would be the end face of the fiber. For a 1mm dia fiber, the area is small.
Fiber manufacturers have to keep in mind the use of CWDM and DWDM(multiple light wavelengths over a single strand of fiber) when constructing fiber cables. They can’t have lightwaves “bouncing around” inside fiber and have it work.
Fiber manufacturers have to keep in mind the use of CWDM and DWDM(multiple light wavelengths over a single strand of fiber) when constructing fiber cables. They can’t have lightwaves “bouncing around” inside fiber and have it work.
I think you’d need a high loss cable, or a leaky cable, so that the light hits the converter in a short distance. If you pick up your 80% of the incoming in a kilometer of coated cable you’ll go broke building a 100 KW array.
Like the guitar strings on a Hard Rock Casino sign, they are made to have strong side emissions to be visible. Um, the strings are fibers, yano.
There always is, though. There is no such thing as a perfect fiber, or connector or splice. All induce some loss into the system. This loss is measurable and determines the distance between repeaters, among other things.
With this solar power application, though, it might be desirable to scatter the light inside the fiber.....
The physics is obvious, but the practical problem is going to be making the electrical connection(s).
I’ve always heard there was about 1000 watts/square meter of potential solar power at noon on the equater and between 600-800 in the U.S.
This link tends to agree.
http://hypertextbook.com/facts/1998/ManicaPiputbundit.shtml
600 W/M2 is 60W ft2, then average that for a 24 hour cycle, and also from North to South in the CONUS, over all the seasons and account for “average” daytime cloud cover.
The nunber I used, 7 W/ft2, is from an engineering textbook.
Solar proponents like to use Phoenix AZ at noon in July for a benchmark but in Troy NY at 10AM in November the number is a bit different.
Perhaps at noon but you need the average value combined with energy storage to compare to power sources.
Unless you we only going to use the power at noon at the equator.
I think the 7w/ft2 is off by a factor of 5 for areas where large solar power facilities would actually be installed.
His response was helpful, the number was for the average CONUS.
Just thinking out loud here and I apologize as this is not my field of engineering (Civil Engineers build targets), but I would think that you would need to lay the fiber bundle in a small, highly reflective tray similar to a oversize rain gutter so that you can focus the light on to the fiber array.
But I am sure they already thought of this...
Thanks for the map. It looks like the southwest would average 30 watts/ft2.
Portland could be problematic.
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