From: Michael S. Lorrey (retroman@turbont.net)
Date: Wed Sep 06 2000 - 10:09:10 MDT
Eugene Leitl wrote:
>
> Michael S. Lorrey writes:
>
> > Assuming 365 days of 10 hours of sunlight for ten years is quite a stretch,
> > Spike. Even in California.... ;)
>
> 1) 10% conversion efficiency and 10 years lifetime is a very conservative
> estimate. I'm not sure whether 500 W/m^2 @ 10 h is too high or too
> low, but I would imagine slightly too low, as the solar constant is
> ~1.3 kW/m^2.
Actually, for thin film amorphous, 10% is about exactly what the conversion
efficiency is. I was wondering where you get your 'insolation' figure from. The
atmosphere cuts solar flux from just over 1.4 kw/m^2 down to just over 1 kw/m^2.
>
> 2) solar cells do not require direct sunlight to generate
> juice. diffuse daylight does nicely, especially when we're talking
> about amorphous cells.
Sure, but their efficiency decreases as flux decreases, and total flux does
decrease with diffusion, as visible is converted to IR. If your flux drops by
half due to diffusion by cloud cover, and the efficiency drops as well as flux
drops, your output decreases markedly.
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