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Cooling swimming pool in high temp - Page 2

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Posted by cjorp@yahoo.com on April 11, 2006, 1:33 pm
 
Ron Purvis wrote:

The average overnight low and the median overnight low are not the same
thing in Tucson -- what actually happens is that the overnight low is
usually somewhere around 82F in July, and on the few nights after
monsoon rains the evaporative cooling effect drops the temp to 65F...
which complicates matters.

This page discusses a solar funnel cooker which can also be used as a
refrigerator at night.  You will notice that the thing is HUGE and can
imagine that a sufficient amount of them to drop the pool temp
significantly would take up a lot of pool deck:
http://solarcooking.org/funnel.htm

--
C


Posted by Ron Purvis on April 11, 2006, 10:07 pm
 


The average means that it is average. Of course there are nights where it is
higher and nights that are cooler. I would doubt that it is only a few
nights that are below 80 F, but will accept that for argument's sake.
However with a 15 C drop below the night air temp, even on the warmer nights



I don't think it is possible to place a bunch of cookers on the deck, and
certainly would not be something that a resort would want to do. This is
something that would need to be placed on the rooftops. It is also something
that would be much easier to do in very cheap solar hot water type
collectors. They probably would not even use glass covers, just copper pipes
with a reflector underneath.



Posted by meow2222 on April 12, 2006, 4:43 am
 Ron Purvis wrote:


Stagnation temp is not very low with this approach, and a lot of area
is needed. If it fits with other considerations, one way to achieve
this is to place a funnel reflector around the whole pool, possibly
using sliding rails and silver mylar curtains etc.


NT


Posted by cjorp on April 12, 2006, 5:50 pm
 Ron Purvis wrote:


Well, FWIW, I live in Phoenix, which is quite similar, and the nights
are only rarely below 80F.  On July 14, 2003, our official overnight
low was 96F.

--
C, votes for shadecloth


Posted by nicksanspam on April 12, 2006, 8:27 pm
 

A more expensive "solar pergola" might block most of the summer sun (84.4
degree max elevation) and reflect more winter sun (34.4 degree max elev)
down into the pool, like this, viewed in a fixed font like courier...

                                  84.4              34.4
                                   .      .        .
                                  .     .       .
                                 .    .   b  .
                                .   .     .
                               .  .    .
                              . .   .
                             .  .
                            .
--------------------------------------------------------
                          / .          /
                        /.  .        /
                      / . e .      /
                    /  .    .    /
               /  / b .     .  /
             1  /    .      ./
           /  /     .      /.  y                     south -->
            /      .     /  .
          /       .    /    .
        /        .   /      .
      /       g .  /        .
    /  a       . / a        .
--------------------------------------------------------
   |     s     |            
   |           x            |

If the slats (dark above and reflective below) have length 1 and angle
g = 180-84.4 = 95.6 and a = 34.4 + b degrees and a + b + g = 180, then
b = 25 degrees and a = 59.4 degrees and x = cos(a) = 0.509 and y = sin(a)
= 0.861 and e = 5.6 degrees and s = x - 0.861tan(5.6) = 0.425.

Nick


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