According to an article in the Atlanta Business Chronicle, Emory University has started an innovative program to capture some of this normally invisible water and use it instead of treated water from the tap. John G. Fields, an Emory engineer, says the program will generate more than 2 million gallons a year for use in an air-conditioning system on campus.

"In the summertime when you have an ice-cold glass of Coca-Cola, it sweats," Fields, director of project management and construction, says. "What causes that is that the liquid in the glass is significantly colder than the outside air. The moisture that's in the air all around us condenses on that cold surface and makes a puddle underneath the glass."

The same thing happens with an air-conditioning unit, Fields explains. Moisture collects on the cooling coil and runs down into the sewer system. Instead of letting it go, Emory is capturing this water - called condensate - and pumping it into the cooling tower that air conditions two buildings.

"The cooling tower needs 10 [million] to 12 million gallons within a year because it evaporates," Fields says. "Instead of buying all that treated water, we're able to make up about 2.5 million gallons in a year from simply catching water and pumping it into the tower."

Fields said the system to capture and use moisture from the air was developed at a cost of $30,000, funded by the university. The university claims it will make up this cost in three years from savings in sewer fees and water usage.