[EMAIL PROTECTED] wrote:
Stephen A. Lawrence wrote:
[snip]
> And how much electrical noise energy is the cell converting back into
> radiation, eh? If everything's at the same temperature you'll most
> likely find the amount of radiation the cell is generating, as a result
> of "running backwards", is equal to the amount of radiation it's
> converting to electricity. You should at least check that possibility
> carefully before you invest any money in a scheme based on this
effect! ;-)
A solar cell providing work absorbs more radiation than it radiates.
Sure it does. But a solar cell operating in the visible spectrum, with
a source which is at room temperature, is /not/ "providing work". (At
least no solar cell I've ever heard of could "provide work" under those
conditions!) It's that case which I'm addressing: Like all the other
materials in the room, the solar cell is radiating.
You think that unlike other materials in the room, it radiates less than
it absorbs under those conditions. I'm saying I'm not so sure.
Experiment can't give the answer at this time, of course -- or, rather,
any real experiment using real solar cells will support my claim, not yours!
>> That is storing ambient temperature energy to a capacitor, which will
>> indeed drop the net temperature in the closed system. Understandably
>> even present leading edge photovoltaic cells are highly inefficient at
>> such low radiation levels, but by laws of probability such a
>> photovoltaic cell will generate DC electricity.
>
> The "laws of probability" predict that if you wait long enough you'll
> fly up into the air because the molecules under your chair will all get
> together and bump the bottom of your seat at once. That's a violation
> of the second law, too, and in exactly the same sense.
Indeed, but I'd bet my money on a visible light photon striking a solar
cell and thus causing a charge differential on the output occurring far
before your body atoms reach coherence.
And I'd bet 1,000,000 times more on being able to extract useful energy
from the temperature difference obtained by driving a metal stake 3 feet
into the ground, at any point in the country, any time of the year, than
on your ability to extract useful energy from a solar cell sealed in a
room with _no_ sources more intense or warmer than the ambient and _no_
objects cooler than the ambient temperature.
The point is, even if you were right that you could get _something_ out,
the extracted energy is going to be insignificant, even in comparison
with such trivial and generally ignored sources as geothermal energy
from extremely shallow wells -- as with my 3 foot metal stake above.
Again, all matter at room temperature radiates visible light photons.
At 300 K one side of a flat 1 x 1 m^2 panel emits 203 nW of radiation
between 1600 nm and 400 nm. Those are photons present photovoltaic
cells are capable of using.
Regards,
Paul Lowrance
