Best thing Susan and I found for pool heating was a *dark* blue
pool cover and running the pump during sunny hours only. Our
theory was there would be more heat loss at the surface if
the temperature was allowed to rise, so stirring the water
during the day would circulate the hot surface water just
under the cover, mixing it in with the cooler water. Having
a high water-air temperature differential allowed the
maximum heat transfer. By *not* circulating and stirring
the water at night, the top layer of water would cool, but
not mix with the warm water. What can I say, we were nerds.
Covers also prevent heat loss through evaporation, which has
a cooling effect. The downside of covers is you have to remove
them each time you want to swim, requiring a take-up reel on one
end of the pool. Upside is they cost only $100 every 1-2 years
to replace.
In very sunny places like Florida, people put those black
solar roof blankets inline with the pool pump and just don't
use a cover most of the time since their pools are often
shaded. Otherwise you die. JT has some unrelated near-death
stories to tell about Florida, but I digress. The more
sophistocated ones are incased in weatherproof glass boxes.
Fafco Solar has has decent home products:
http://www.fafcosolar.com/
Someone I knew once zig-zagged a black garden hose on the ground
beside the pool, circulating pool water through it, but they
were crazy.
dc
Richard Conner wrote:
> Hmm... interesting ideas... how about a little more details -
> I was thinking I'd use a half an actual sphere so that focus should be
> at a constant point within the device without needing to adjust for
> sun tracking as well as being tolerant of constant minor movement of
> the hemisphere. What I am actually interested in investigating is
> feasability of an *extremely* cheap solar pool heater. Hemispherical
> concentrator heating copper element transferring the heat into the
> water within the tube causing thermosyphoning to draw water up from a
> few feet down, and spilling over sides of hemisphere. If they could
> be made to work, and were cheap enough, it might be possible to drop
> several in a pool
> -- or I could just be smoking crack. :-)
Richard, I think it's time you shared with the group.
dc
Received on 2004-06-11 23:24:45