Cooling towers are designed to cool fluids using evaporation to get very high efficiency levels.
Conventional 'dry' coolers pass air over a warm fluid to remove the heat from that fluid. A cooling tower will either spray the fluid itself over a heat exchange surface while passing air over it in an open circuit design. Alternatively a closed circuit design has a separate reservoir of cooling fluid which is used to cool the main fluid without this main fluid ever being exposed to atmosphere.
You can see more information on our partner companies website below
Cooling Towers and Legionella
For information on managing the risk of legionella contamination see the HSE website here