A cooling tower is the final destination of unwanted heat within a building. It absorbs heat from hot process streams and transfers it to the air. The warm water trickles over the fill material in the cooling tower and contacts the ambient air rising through the tower, which may be natural or forced draft using large fans. The heat transfer from the water to the air results in windage and some evaporation. The heat transfer rate from a cooling tower depends on its size and airflow.

Often, cooling towers are located in precarious or exposed locations, making inspection difficult. Hence, they require regular cleaning and maintenance. Fall prevention measures, such as lock-out/tag-out procedures, must be followed by workers.