Evaporative coolers are a cheap and efficient way of cooling down large areas where conventional air conditioning would not be feasible. Evaporative coolers work on a very basic principle of blowing cool moist air into a well ventilated area. The machine is simply filled with water and a pump draws the water to the top of the machine, which then runs down specially designed pads. At the same time a fan blows the moisture through the pads releasing moisture into the atmosphere.
The best way of describing the feeling is imagine yourself standing at the seaside with the breeze blowing across the water collecting moisture which then hits your body giving you that nice cool feeling. Evaporative coolers also have uses in areas where a high concentration of moisture is required, like your local florist, as the last thing they want is for the flowers to dry out. Also, some asthma sufferers may feel the benefit of the cool moist air enabling them to breathe easier.