Evaporative Coolers for Swimming Pools

Is the pool above ground?

If so, keeping the water level below ground level should help a lot.

A spray pond ought to work for this. Off to the side of the pool, make a basin with with an array of nozzles spraying upward and falling back into the basin. Pump from the pool to this piping array, and let the water gravity drain back to the pool.

The pool will need more than the previous make-up water, which may require adjustment of the chlorination or other treatment system.

Offhand I don't know how to size this, but maybe it's a start.

Do not work with them, but know : the output of an evaporative cooler depends on ambient air relative humidity (no latent heat can be get at 100 % RH).

And I believe a more or less effective evaporative cooling is impossible without fans - one needs a water-to-air heat rejection point.

Probably, in the end, you would not do without a refrigeration cooler (750 tons of water is too much to achieve a not too lenghthy cooling down from 40C to 25 C - by an EC ).

Humid air at those temperatures is 4% lighter than dry air. It'll also be 15 C cooler and therefore 1% heavier overall. Natural convection won't work.

You need a 1 m^3/sec air flow rate, a $20 window fan.

Pool chemicals are expensive and 1000 m of 25mm sch 20 pvc tubing is only $300.

You already have a pump and a fan so you might as well make a cooling tower.

Just make sure you have a lot of parallel lines to keep the pressure drop and pumping costs down.

A 0.5 kW pump will pump 100 liters/min through 10 lines because the pressure drop is so low.

The only part of a cooling tower that may be a problem is making sure there are no dead spots. There's something in heat transfer handbooks about how to space and locate the pipes.

Bret Cahill

25degC?

OK.

What's the wet-bulb temperature of the surrounding air? If it's ordinarily over 25degC, then evaporative cooling will only work if a fridge plant is installed as well.