From: Spudboy100@aol.com
Date: Wed Sep 06 2000 - 18:09:09 MDT
I have to break in on this topic with a reminder. Solar is something I am
100% for, however, what will liberate solar and wind, or rather ignite it,
will be the conversion of photovoltaic and wind energy into fuel for fuel
cells or perhaps, flywheels. Storage for evening or dark day times is the
key. All weather solar power and wind power are another issue. If we just
listen to the blathers about solar being merely a sunbelt energy, it will
never take off. Fusion looks plausible, but directionless, and therefore
gut-shot.
In a message dated 9/6/00 10:47:45 AM Pacific Daylight Time,
eugene.leitl@lrz.uni-muenchen.de writes:
<< Michael S. Lorrey writes:
>
> 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
True, but you can get 20% panels, too, and more, if price is
irrelevant (~32% is about the best we can get iirc with multilayer
GaAs). With 10% I'm operating on the low end of the efficiency
spectrum, not coincidentially the best efficiency in wattage/$
produced.
> atmosphere cuts solar flux from just over 1.4 kw/m^2 down to just over 1
kw/m^2.
The insolation figure is totally ad hoc, since I don't have access to
my library, and a websearch via dialup in Krautland is a bear. I just
thought that 0.5 kW/m^2 on the average over a 10 h period in
California-type area is the about the right ballpark figure, if the
solar flux constant is 1.3 kW/m^2. I would of course welcome seeing
real numbers.
> > 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
I thought thin-film amorphous did at least NIR rather well.
> half due to diffusion by cloud cover, and the efficiency drops as well as
flux
> drops, your output decreases markedly.
I did not know the average number of cloudy days in California, and
just took 365, assuming the few 10 days would not make a difference,
as other parameters have been chosen rather conservatively, and this
is a back of the envelope estimate.
Nitpicker! >>
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