They are called evaporative chillers or swamp coolers. They work on the principle that heat is required to evaporating water so if the water evaporates it takes heat out of the air as the water turns into gas. Evaporative coolers work best in low humidity so they are not as effective here in the Deep South as they are in dryer climates but they do still work.We were planning to have friends over last Sunday evening and it was obvious that the cool spring we had been enjoying was over. The thermometer was registering 104 F in the shade on Saturday so I decided to build a “swamp cooler” for the event.
I already owned a shop fan and had the 3/4 inch PVC pipe and most of the fittings necessary for the project. From Home Depot’s irrigation department, I purchased 4 mist sprinklers ($8.36) and the required pressure regulator/filter ($14.98). These items along with the fittings I already had allowed me to put the project together in about 30 minutes. My project is made from 3/4 inch PVC but it can just as easily be made from 1/2 PVC (or from the even cheaper black irrigation pipe). The parts list for my project is:
1 – 8’x3/4″ PVC pipe
4 – 3/4×1/2 slip to pipe threaded PVC Tee
4 – 1/2 in pipe thread adjustable irrigation misters
3 – 3/4″ PCV elbows
1 – 3/4″ PVC plug
1 – 3/4 PVC slip to hose connector
You can see from the photos how I constructed the unit. Once fabricated, I used tie wire to attaché it to the front of the shop fan and connected it to the water hose. I adjusted the flow of the misters so that the spray evaporated before the water droplets reached the sitting area of the patio. While it was not a controlled “scientific” test, the unit dropped the temperature from 104 F to 84 F twenty feet from the fan!
We used the system on Sunday with success. If I can find mist nozzles which produced a finer mist, I think the system would be much more efficient and you could sit closer to it without getting wet. But the readymade models cost over $200 so this one will work for our patio get-togethers! And, Susan kind of likes the spray… I think it reminds her of the beach!
Hey Roy;
Why don’t you also build an inexpensive water recovery trough in front of the mister. You can then place an inexpensive sump/submersible pump(12 volts) in the trough and recover your mister water. You still get the cooling effect but without making a watery mess and saving your water for the garden or reuse somewhere else. I recall us talking about many of the things you have on your website pages now, brings back very fond memories. Keep plugging and God bless.