The selection of a cooling tower is dependent on the design Capacity, which is the flow rate of water that
is to be cooled; the entering or hot water temperature; the leaving or cold water temperature; and the
entering air wet bulb temperature.
If a cooling tower is under sized, a misconception is that the tower somehow or other rejects less heat
than is applied to it. In reality, a cooling tower will dissipate all the heat transmitted to it, but an
undersized tower will do so at higher temperatures than design.
For example, a cooling tower selected with an approach of 5 degrees and a range of 5 degrees, would if it
had a 25% deficiency in its sizing have an actual approach of approximately 7 degrees, which is
approximately 40% higher than the original design requirements.
