It's been said that we could reduce city temperatures by painting all the roofs white. Solar panels are almost black, but at least they are usually spaced a bit above the roof.
Birds have adapted well to cities; we have deafening bird conventions in trees around here. And gigantic ravens and hawks. Lots of hummingbirds.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
This summer I trouble-shot a 100W 12V panel that's putting out 1/3rd the rated short-circuit current.
Shorting the panel in full summer sun produced several 'hot spots,' easily identified and localized to small areas on a few cells. The hot areas are always local to foci on one or the other of a cell's two current- collecting bus metallizations, e.g.
| | | | | | | | .------| |-------| |------. .------| |-------| |------. | .....| |.......| |..... | | .....| |.......| |..... | | .....| |.......HOT..... | | .....| |.......| |..... | | .....| |.......HOT..... | | .....| |.......| |..... | | .....| |.......| |..... | | .....| |.......| |..... | | .....| |.......| |..... | | .....| |.......| |..... | | .....| |.......| |..... | | .....| |.......| |..... | | .....| |.......| |..... | | .....| |.......| |..... | | .....| |.......| |..... | | .....| |.......| |..... | | .....| |.......| |..... | | .....HOT.......| |..... | |______| |_______| |______| |______| |_______| |______| | | | | | | | |
This suggests a high-resistance failure, but I'm not sure if it's at the heated site, or from high-resistance at a lateral displacement forcing excess current through the heated site.
I'll go through the backing and jumper around the affected cells eventually.
Cheers, James Arthur
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now, and the lifetime is supposed to be about 20 to 25 years.
ace to collect all the power we currently use. A 0.1% change in albedo isn' t going to matter - particularly when the albedo of the "perfectly white" desert sands John Larkin expects them to cover is only 0.4.
That sort of fits my number. The US is about 4.5% of the world's and area, or about 1.3% of the planetary surface area and generates 25% of the world 's power, so they'd need cover about twenty times as much of their surface area as the world as a whole. Wind farms are another way of collecting sola r power, and don't mess with the albedo at all.
That puts current payback times at around 3.5 years, twice as good as I'd r emembered, and puts the payback time at thirty years, marginally long than the 20 to 25 years I had in mind.
-- Bill Sloman, Sydney
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