You’ve probably seen countless cooling towers without realizing it — many businesses rely on these devices to maintain an ideal temperature for many different machines and heat-producing processes. Here’s just a little more information about these devices, how they function, and why they matter:

What is a cooling tower? There are many different types of industrial cooling towers with very specific purposes, but the most basic definition of a cooling tower is that it’s a heat-removal device, used to transfer waste heat, out of systems and appliances, and into the atmosphere.

What is waste heat? Waste heat isn’t necessarily bad for the environment like traditional waste or garbage usually is; it’s simply the heat produced by certain devices, like air conditioners and power generators, that needs to be transferred away from the device so that it doesn’t overheat and malfunction.

How do cooling towers work? Every type of cooling tower works a little bit differently, but the most common towers use water and evaporation processes to remove excess heat and are called wet cooling towers. First, a stream of water runs through the device and absorbs the excess heat. Once the water has heated up, a stream of cool air is pushed through the tower, causing some of the hot water to evaporate and escape; the water that’s left after evaporation is significantly cooler, and can start to absorb excess heat again. Dry cooling towers are fairly common as well, particularly in car radiators, and these don’t use any water streams; these types of cooling towers are often less preferable because they aren’t as energy-efficient or cost-efficient.

Who uses cooling towers? Bigger industrial cooling towers — possibly the size of a small building — are often used by manufacturing companies and refineries that constantly use heat-producing equipment. Smaller cooling towers can be simple devices that rest on rooftop and process only a few gallons of water through the cooling system.