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Posted by Solar Flare on August 6, 2008, 1:36 am
 
Try some PV and then count your loses over conventional methods. Count
honestly with open eyes. It's a complete waste of money. A lot of fun and
interesting but the investment loss on the money alone will never be
exceeded by the energy costs saved.




Posted by Morris Dovey on August 6, 2008, 3:09 am
 
Solar Flare wrote:

[ Still reading in news:alt.solar.thermal ]

I don't know enough to talk about PV. My understanding is that a
reasonable PV radiation->electric conversion efficiency is somewhere
around 10% and I've read that the cost per watt is around $-$ per watt
of capacity, with significant add-on cost for storage. If that's even
close to accurate, then PV is too expensive for what /I/ would want it
for. However, I'm optimistic that PV system costs (like computers, VCRs,
DVD players, microwave ovens, etc) will eventually decline.

Passive solar heating is a different story altogether. I've seen passive
solar work exceedingly well for (adjunct) space heating and have a whole
pile of to-do projects to make it work even better as a primary heating
system. The radiation->heat conversion is considerably more efficient,
and the cost of even exceptionally efficient panels can be quite a bit
less on a per delivered watt basis.

I haven't worked much with water heating panels, but I would expect that
the radiation->heat efficiency arithmetic is essentially the same, with
allowance needing to be made for pump, controls, and storage.

I've been working with solar-powered Stirling engines to perform the
radiation->mechanical energy conversion and have made enough progress to
see real potential for their application in a number of applications.
The high temperature version is capable (on paper) of a conversion
efficiency of just over 50%. That's wouldn't be particularly exciting
except that the construction cost is very low, the longevity can be
exceedingly long (depends on materials used), and the
operating/maintenance costs are so low as to be negligible.

I have seen PV used for remote, unattended applications where
electricity is required but a grid connection isn't available. Here in
Iowa, for example, there are stretches of highway monitored by
PV-powered "wireless" cameras to reduce the requirement for vehiclar
patrols. We similarly use PV-powered systems to monitor windspeed, air
temperature, precipitation, and pavement temperature around the state.

I don't see any of the above as falling into the "complete waste of
money" catagory.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/solar.html

Posted by Solar Flare on August 6, 2008, 3:30 am
 It is a complete waste of money over conventional methods of energy, if
available. read the whole paragraph.




Posted by Morris Dovey on August 6, 2008, 4:33 am
 Solar Flare wrote:

[ still reading at news:alt.solar.thermal ]

I did, and still think you're talking through your hat.

The panels at http://www.iedu.com/DeSoto/solar.html  were adequate to
keep that farm shop building shirtsleeve comfortable through the past
winter. Both electricity and gas (propane) are available, and the total
energy cost for heating that shop through the past winter was $.

One of the owner's neighbors liked what he saw (and felt) and had me
stop by his place to quote panels for his (slightly smaller) farm shop
building. I took photos and you can see the southern exposure of his
building at http://www.iedu.com/DeSoto/Misc/RTShop.jpg

He showed me his gas (propane again) bills for heating this shop through
the winter before - and his total was a bit over $00 (and the price of
propane has increased noticeably since then).

The first guy figures that his solar heating panels have already paid
back the first $000 of their cost - and would agree with me that you
need to rethink your statement about solar being "a complete waste of
money".

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/

Posted by Solar Flare on August 11, 2008, 3:17 am
 Funny PV system. Can you read at all?



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