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In article <122@gazette.bcm.tmc.edu> andreask@watson.bcm.tmc.edu (Andreas Kasenides) writes:
>I am very much interested in solar energy as a means of powering up
>household devices ( lamps, heaters, AC's etc ) and not just as a means 
>to recharge my rechargable batteries ( which I do not use very often
>anyway ). 
>
>I would like to know and get the opinion of those on the net that have
>experience on this subject. Specifically
>
>  1) Is it feasible ?
>  2) What are the requirements ?
>  3) Is conversion of solar energy, say, to heat rather than electricity
>     more desirable.
>  4) Will the cost of the system make it economically unsound ?

Solar heating is extremely effective in middle latitude climates if it
is designed into the building.  The payoff can be much longer if you have
to retrofit but is almost always worth investigating if only from an
environmental perspective.

In any energy supply conversion, you have to determine the amount of money
that your current energy source costs per hour (since its capital expense
is likely paid off).  Then compute the capital cost of the conversion and
divide this by your current energy cost.  This tells you how many years
it will take to pay off the conversion.

If you're very interested in saving the environment by using renewable
energy sources, this period can be a long time.  If you're a business
owner with angry stockholders, this will be a shorter time (but do it
if you can).  I think 7 years or so is reasonable for homeowner projects.

As for specific conversions:  if you're interested in powering appliances
etc. you almost have to use the solar system or backup utility power to
charge a bank of batteries, then run the appliances off of the batteries.
This by the way is how the best UPS systems run.  Quite naturally this
can get expensive.

If you're willing to have separate circuits and switch to another light,
heater, or AC system when the sun goes down or behind a cloud, then it
can be a lot cheaper.  Oh, by the way, don't use solar cells for heating.
Direct solar heating will be much more efficient because the conversion
factor for solar cells into electricity is 10% or less.  You're much
better off using the heat directly.

You can get an idea of how expensive solar cells are by visiting your local
marine or RV supply house.  Boats in particular often don't have extension
cords long enough to power their refrigerators :-).  One of these days I'm
going to look into solar panels to power the refrigerator in my VW camper.
The 50 AH deep-cycle marine battery (size of a regular car battery) only 
runs the fridge 10 hours, and if I don't drive for a day or so everything 
spoils.

Interesting story:  last summer, while riding down the Pacific Coast on a
bicycle, I met someone who was walking from San Francisco to San Diego.  He
had a 16-watt solar panel attached to the top of his backpack, almost as a
parasol.  This in turn powered a Zenith laptop.  He was writing a book as
he walked!  These solar panels, by the way, were amorphous:  lower efficiency,
but (I think) cheaper than the silicon-wafer ones and *much* less fragile.
You could bend them.

>I can summarize if enough interest is shown. Please ask me to summarize !

Yeah, yeah, you wanted E-mail rather than posting, but I decided that my
response was of general interest.  :-)  Net mail tends to bounce anyway.
And finally, with a message this long I can waste much more net.bandwidth
by posting than by mailing.  :-) :-) :-)
-- 
		David Chapman

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