Evaporative cooling is not a modern concept — in fact, its origins can be traced to ancient times when Egyptians hung wet blankets across the doors of their homes to cool the space as fresh air blew in. During the 1800s, New England textile mills used a similar approach. Today, more sophisticated evaporative cooling systems are used for applications from industrial processes to dry cleaning facilities to schools to modern data centers.
Evaporative cooling is an efficient and relatively inexpensive method for cooling buildings and products, yet it remains underused. While the basic technology of the process of evaporative cooling is well understood, its potential — and its limitations — often are not. An understanding of evaporative cooling starts with the three different categories of systems: direct, indirect and hybrid.