Large structures that dissipate heat from data center cooling systems by evaporating water. Cooling towers are the primary source of data center water consumption, using 3-5 million gallons per day for a large facility. They work by spraying water over fill material while fans draw air through, evaporating water to remove heat. Visible vapor plumes from cooling towers often prompt community concerns about visual impact and water usage.
Discussed in Chapter 3 of This Is Server Country