You might have noticed this huge beehive like structure around industrial zones and wondered what they were all about. They are most often used alongside power plants but nowadays you may find them in a variety of industrial settings. They are used in many different applications such as very tall large scale towers at nuclear plants to very small box type cooling mechanisms at dry cleaners or even in home settings. Mostly used for central cooling they are widely used as refrigeration apparatuses, cold storage, dry cleaning and even in manufacturing industries. Their main role as the name itself suggests is to remove unnecessary or excessive heat from different environments such as industrial settings or even residences.
The process most often used is quite the same, which is to use a water cooling system such as a suitable heat exchanger to extract the excessive heat that is generated and releases it to the air though the large tube like vents. This is also known as “evaporative” heat rejection. The use of cold water is considered much more energy and cost efficient than using dry air or non cool water. How the method work is similar to pouring cold water on a hot pan, the cold water cools the pan much faster releasing steam than normal water or air. The cooling mechanism transfers water in from one medium to another often using water as the transporter. The cool water is pumped and taken away from the tower and are sent through the hot machinery which absorbs the excessive heat that is generated. The warmed liquid is then sent back to the tower which is sprayed or blown back up to the air with the use of industrial fans. In this process some water content is lost due to evaporation.
Cooling towers come in various sizes and can serve different purposes. There are over 400 metres tall structures in power plants or smaller versions in residential settings. The size and structure of the heat rejection system depends on the heat that is generated. Small heat sources might only use a HVAC model (Heating, Ventilating, and Air Conditioning), which will include a tower, a chiller & pumps for creating water loops. But larger scale operations such as refineries or chemical plants will require an industrial grade tower which will limit the need of discharging large amounts of water back in to water sources. Though using these plants are considers very efficient, Some plants make use of water sources such as the ocean to replenish water stocks that are lost and in the evaporation method some water is lost anyway. Therefore environmental implications of this method need to be monitored continuously while including strict measures to avoid wastage.