You can also view previously answered questions in the HSW Question Archive . There are several different ways that water is used in air conditioning. The most common use is in cooling towers. A more direct form of evapoartive cooling is often found in green houses, farmers' markets, chicken houses, etc.
Water flows over a mesh and a fan blows air through the wet mesh into the building.
Humid, cooler air is the result. This device from Sharper Image is another take on the evaporative cooling idea. Inc. All rights reserved.