Cooling towers transfer heat using water as the heat transfer media. A small portion of the circulating water is evaporated to the atmosphere, removing heat from the remaining water volume.
In a cooling tower system, water cascades over the tower, providing a large surface area that allows a large volume of air to pass through the water, aided by the cooling tower fan. A portion of the cascading water evaporates, ejecting heat from the water to the atmosphere. The remaining circulating water is cooled from the heat removed by the evaporation. Since water is continually lost by evaporation, cooling tower systems require large amounts of make-up water to stay in balance.
The problems to address when treating cooling towers are: Scale, Corrosion, Fouling and Microbiological Contaminant.