How do transfers take place in cooling towers?
A Cooling towers is a special type of heat exchanger that brings water and air in contact in order to lower the temperature of the (hot)water. All through this process, a small part of the water is evaporated (roughly 0.15% per centrigrade of cooling), lowering the temperature of the remaining cooling water that circulates over the cooling tower and connected heat exchanger (where it increases from taking on the excess heat to be removed from the process). In short, a cooling tower cools down water that gets heated by equipment and industrial processes.
Usually, the water is heated by air conditioning condensers or other industrial processes, after which it is pumped to the cooling tower. Cooling tower nozzles are used to spray the water evenly onto to the “fill media”, which slows the water flow down and provides maximum heat exchange surface area for the best air-water contact. The water is exposed to air as it flows throughout the cooling tower. The air is being pulled upward through the fill by the cooling tower fan that normally is powered by an electro motor.
The evaporation of water requires energy as water vapor has a higher energy state then liquid water. This energy is withdrawn from the cooling water as result of which this water cools down. The best possible result in a cooling tower cooling tower is a outgoing water temperature that is 2.7⁰C above the so called Wet Bulb Temperature, which normally is below ambient temperature.