Many of us are familiar with the huge, chimney-like structures that are seen outside of power plants emitting some sort of fog from their immense chutes. Some of us may know that these behemoth structures are actually cooling towers that are necessary for getting rid of the massive amounts of heat generated during the various processes that go on in a power plant. But even fewer of us are aware how these marvels of modern engineering work, or that this type of cooling tower is but one of many. Here is some information regarding the operation of cooling towers and cooling tower replacements.

What are cooling towers? While many people might be vaguely aware that cooling towers are a thing that exists, most of them hardly have any idea how they actually work. Of course, they are used for cooling; that much is obvious from the name. But how does a cooling tower work, exactly, why are they needed in the first place, and what happens when cooling tower replacements are needed? Cooling towers are mostly used in industrial settings and operations such as HVAC (Heating, Ventilation, and Air Conditioning) systems, nuclear power plants, and oil refining facilities. The large, iconic cooling towers with which most of us are familiar are tall, open-topped, cylindrical concrete towers (the world’s tallest is a 202 foot monster in Jhalawar, Rajasthan, India) that are used for cooling water or condensing steam that is the byproduct of an industrial process. The first of these “hyperboloid” cooling towers was built in 1918 in the Netherlands. HVAC cooling towers are used specifically to reject unwanted heat from a chiller.

But how do cooling towers work, you may be wondering? There are two ways in which a cooling tower can work to cool the waste heat that is the byproduct of so many industrial operations. Cooling towers can either cool with air, or using the natural process of evaporation. When cooling with air, the water that has been used to absorb the waste heat is first pumped to the top of the cooling tower. The water is then directed to flow down a path so that it turns into droplets. As the droplets form they are met with a current of air that is flowing upward and past the water. This air is what cools the water. The fully cooled water is then collected at the bottom of the cooling tower to be reused in the production process.

Cooling towers that use evaporation to cool their water take advantage of the natural chemistry of water. As water transforms from its liquid state to its gaseous state, it rises into the air and cools automatically. However, this method of cooling is highly dependent on the surrounding climate. In order for the process to work efficiently, there must be a large difference between the air temperature and the water temperature. As such, evaporation cooling towers are rarely used in hot and humid climates. The inside of a cooling tower is already a harsh and humid environment that leads to many cooling tower replacements. Cooling towers that use evaporation are best suited to cool, dry environments. And this water can even be recycled to be used as drinking water in areas without a suitable water supply.