Have you ever wondered what those cloud-billowing towers next to factories and large buildings are for? They’re actually cooling towers, and they serve a crucial operational purpose.

What are cooling towers?

Cooling towers were developed from the condensers used in steam engines in the 19th century. They extract waste heat to the atmosphere by cooling water to a lower temperature, either through evaporating water and cooling the working fluid to near wet-bulb air temperature, or by relying on air to cool the working fluid to the dry-bulb air temperature.

Early towers were positioned on rooftops or as free-standing structures that resembled short, stout chimney stacks with a set of troughs on the top and used fans or natural airflow.

What do cooling towers do?

Industrial cooling towers remove heat absorbed in the circulating cooling water systems used in petroleum refineries, food processing plants, power plants, natural gas processing plants and other industrial facilities. This allows the cooling water to be used again.

Industrial cooling towers are often large hyperboloid structures up to 200 meters tall and 100 meters in diameter, or rectangular structures that can be more than 40 meters tall and 80 meters long. The worlds tallest cooling tower is Kalisindh Thermal Power Plant’s 202-meter-tall structure in Jhalawar, Rajasthan, India. Smaller towers may service HVAC systems for individual buildings.

What types of cooling towers are there?

There are many different types of industrial cooling towers, though they mainly split into natural draft and induced draft cooling towers. Industrial draft towers have fans at the top witch pull air up and expel the hot air. Natural draft towers are tall chimneys that allow warm air to rise naturally.

Cooling towers and their components work in many different ways to get the job done depending on the needs of the building they service, and this only scrapes the surface of how they function.