David Nebenzahl wrote:
On 4/8/2009 1:01 PM The Daring Dufas spake thus:

dpb wrote:

The Daring Dufas wrote:
...
a combination system on a small scale for a home. A
solar cell system combined with a liquid heat collector.
It shouldn't be too hard to develop.

Solar water heating has been around for years as well...it's one of
the areas that does have some reasonable payback in some areas as it
doesn't have the problem of the low conversion efficiency of PV, only
the low (relatively) energy input density.

I don't know what you want for the electrical generation side in your
wishlist, though--the size reqm't for useful output of any real
magnitude would be a problem if you're talking turbine-generator type
generation instead of direct conversion it would seem.

My thought is to combine concentrating mirrors to increase
the efficiency of the solar cells. This may cause high enough
heat to damage the solar cells without active cooling. The
heat from the coolant could be used for heating water or the
living space. Some of the power generated by the solar cells
would always be used to run the cooling system and possible
movable concentrator mirrors. There are lots of low power
electronics and motors that could be utilized.

Interesting idea (that you've mentioned here before).

Not to throw cold water on it, so to speak, but I'm just wondering if
existing solar concentrating technology isn't simpler and perhaps more
efficient. After all, we already have large solar plants that work by
concentrating sunlight on collectors and boiling some substance to drive
generators. (I don't think they use water, but some other material with
better heat-transfer qualities). Wouldn't it be better just to tweak
those units, rather than adding the complexity of PV into the equation?



If I remember correctly there was research done on this
here in the US years ago but Spain seems to have picked
up the ball and run with this technology, using heliostats
which are large mirrors to focus the sunlight onto a
central tower. More about it he

http://en.wikipedia.org/wiki/Solar_power_in_Spain

TDD