Redneck pool cooler: chemical interactions?

[Slowpoke]

I want to cool the 1500 gallons of water in my AGP from 98 degrees F down to 90 degrees (or less would be even better).
I built an aeration system to do just that, but it didn't cool the water down more than about 4 degrees, due to lack of temperature differential between the air and the water (it was, however, very effective at reducing the TA & increasing the pH).

I am considering pumping the water through a radiator which will have cold air from a window unit air conditioner blown through the fins. I work at a trucking company, so getting a large radiator is not an issue.

Ambient air temperature here is around 100 degrees F, give or take 3 degrees. I know that window unit air conditioners can blow air in the 65-68 degree range in this climate, so I'm anticipating a 30 degree temperature differential between the air and the water.

My question is: could there be any chemical interaction between the chlorine in the pool water and the aluminum in the radiator?

Also, is there anything else I need to take into consideration?

Thanks!

 

[chem geek]

It's not so much conduction with a temperature differential but the rate of evaporation that determines the cooling. So rather than blowing cool air over the droplets which won't cool them off very quickly, it would be better to blow DRY air instead. It's probably humid where you live so the rate of evaporation is slower as a result, in spite of the high temperatures. If your air conditioner blows out cool dry air, then it's the dryness of the air that will be most important. Otherwise using a dehumidifier to blow dry hot air through the pool spray will likely be even more effective. Of course, if you overdo it so that the drops completely evaporate, then you won't be putting back any cold water back into the pool!

Roughly speaking, 1/4" of evaporation cools a pool with average 4.5 foot depth by about 5ºF.

 

[stev32k]

I'm not sure about any reactions between aluminum and chlorine, but if there is any copper in the radiator you could end up with staining in the pool. If your aerator is not cooling the water down you need to increase the amount of aeration and produce smaller droplets or run it for longer periods. Just spraying a stream of water like from a water hose in the air will not be very effective. Put together PVC pipe in a "T" shape and drill 1/8" holes in two or three or four rows across the top of the T and plug both ends. The idea is to make the drops as small as possible. Smaller drops will allow more evaporation in a shorter period of time.

Some people make up one aerator like this for each return then run the pump until the temperature comes down. You should be able to get the temperature down to 80 F or even lower depending on the humidity. It may take a while, but it will work.

 

[Slowpoke]

Stev32k, I have already built a "water fountain" that is practically identical to the one you described. It does cool the water a little bit, but not as much as I'd like. My aerator (bubbler ring) does not cool the water very well at all. And thanks for the heads up about the copper. I think the ones we use are all aluminum, but I will double check.

Chem Geek, I think you may have misunderstood my intended design. I'm not talking about blowing cold air through the pool spray, or across the surface of the water. I'm actually talking about blowing cold air through a radiator, which will have pool water circulating through it (imagine placing a window unit air conditioner directly in front of your car's radiator). There will be no contact between the air and the water; the heat transfer will occur across the radiator metal, as it does when a radiator is installed in a vehicle.

Thank you both.

If this works, I'm gonna wrap the A/C unit in camouflage, and post pictures!

 

[linen]

This has been discussed before, here is one example: http://www.troublefreepool.com/cooling-a-pool-with-automobile-radiator-s-is-it-feasible-t48939.html...there are more if you do a search.

A radiator will be very ineffectual in cooling due to lower temperature differences between the air and the water (even with the cold air from the air conditioning unit).

A solar panel run at night will work much better...as will evaporative cooling. Makes sure you are getting a lot of small water droplets from your current cooler. The more surface area, the more evaporation and the faster the cooling.

 

[Slowpoke]

Linen: Thank you for the link. I had assumed that the cold air passing through the radiator would be enough of a temperature differential to achieve some effect, but apparently that is not the case.

I will definitely make 2 new heads for my fountain (one is simply a screw-on PVC cap with holes drilled, the other is a screw-on tee fitting with 8" of pipe extending outward, with caps on the ends). The current ones have approximately 8 holes that are slightly larger than 3/16" diameter. The new heads will have a greater number of smaller diameter holes.

Thanks y'all.