On Sun, 17 Jul 2005 11:50:31 -0700, "SteveB"
wrote:

I have a solar heater on the pool. We live in Las Vegas. It is hot here
now, between 115 and 120 the last week.

My pool water is 94, an uncomfortable temperature.

Call it a hot tub and it will be too cool.[g] My spa temp is set to
hold 99 but the water is 102 here in Tucson.


I know that if I run my system at night, it will circulate the water through
the collectors, and though night time temps are 90 right now, it should
bring the temp down. Plus, not running it during the day will keep the
circulation from going through the panels and picking up more heat.

You can actually cool to below air temperature at night, just as you
can get water hotter than air temp in the sunlight. Trust me, I've
had two different houses with solar hot water heating (neither of
which I had installed, what a dumb idea) that I abandoned because of
winter freeze ups when the air temp was above freezing. The clear
night sky has a black body temperature very near absolute zero (0
Kelvin) so an Earthly black body collector at 0 deg C is 273 degrees
-hotter- than absolute zero. It radiates energy back into space and
cools off.


My questions:

Does not having the water on and running through the panels in the day when
it is hot damage them? It seems like they would get awful hot. When I cut
down the flow to the panels, the water in there reaches 160 degrees. That
can't be good.

It depends on the construction but most panels -should be- designed to
run in a stalled condition.

Should I just run it night and day? To keep the panels from getting too hot
during the day, and at night to help dissipate some heat?

Run it at night.

We like the temp around 85, and that seems to be about 15-20 below ambient.
But right now, ambient is so high that it comes out at 94. Normal temps for
right now is 104.

Tell me about it. We set a new -high- "low" temp the other night: 89
F.


Any suggestions or information by solar gurus would be appreciated.

Not a guru, but did take a college course in solar heating and cooling
a long time ago.