Cooling towers are specialized heat exchangers, but instead of the usual conduction - convection heat transfer of shell and tube heat exchangers, it generates cooling by bringing water and air into contact.
This cooling is achieved through evaporative cooling and sensible heat transfer.
There are different types of cooling towers depending on its air flow generation, air-to-water flow, heat transfer method and construction. Each of these types has its own set of advantages and disadvantages.
There are three important factors that determine cooling tower efficiency: relationship between range and approach, wet-bulb temperature and cooling load.
Because of the continuous evaporation of water, several problems arise such as scaling and biological fouling. Common water treatment methods are water blowdown, filtration, water softening and chemical addition.