How to Make an Evaporative Cooler for Outbuildings

In hot, dry climates, evaporative cooling can be quite effective and more economical than air conditioning, especially for workshops or other outbuildings. This cooler design can drop the temperature more than 20 degrees F or over 10 degrees C and has a relatively low cost to make.

EditSteps

1. 
   Build a box of oriented strand board or plywood that just fits around a box fan. Make it about 12 inches (30 cm) wide. Pieces of scrap lumber serve to give strength to the corners.
2. Mount the box over a window or other opening in the side of the structure you want to cool. Insert the fan.
3. 
   Cut the cooler pad to fit tightly into the box, a little extra size is fine, since it compresses. Place the wire mesh, such as chicken wire behind the pad to hold it against the fan. Hooking it over screws run into the inside of the box helps hold it in place.
4. 
   Mount the mister so that the nozzle sprays mist onto the upper middle of the pad. Using two or more nozzles can improve the performance and is probably necessary to achieve the 20F (10C) temperature drop. Mount the mister nozzles a few inches away from the pad so that the spray will spread out and also cool the air behind the fan. Attach the mister to a water source, such as a garden hose.
5. 
   If you are attempting to cool chickens or other livestock, you may want to place a shield in front of the fan so they are not in the direct full blast of the moving air.
6. Adjust the amount of cooling by the number of mister nozzles used and the fan speed.

EditTips

• 
  An easy way to supply the mist effectively is to cover about 3/4 of the back of the box with aluminum flashing and run one of the stand alone curved tube misters into the box. The air is drawn into the box by the fan through the small opening at the bottom, and the mist cooled air is pulled into the building. A recent test with the fan on medium created a temperature drop of 18 degrees in the building in about 30 minutes.

EditWarnings

• Water and electricity can be a dangerous combination, so be careful to avoid getting too much water on the fan motor or cord. Hooking a piece of aluminum flashing on the back of the fan under the pad, covering the electrical parts of the fan, but leaving the blade area open may reduce contact between the mist and electricity.

EditThings You'll Need

• 20 inch (50 cm) box fan
• polyester foamed cooler pad
• wire mesh
• oriented strand board
• lumber scraps
• screws
• a hose
• a mister

Source: http://www.wikihow.com/Make-an-Evaporative-Cooler-for-Outbuildings