What is a Cooling Coil?

Mary McMahon

A cooling coil is a device intended to allow the contents of the coil to cool as they move through it. Cooling coils can be used in materials processing to control the temperatures of various components, and they are also employed in heating and cooling systems where space is at a premium and other cooling arrangements are not feasible. This cooling mechanism is relatively simple and can usually be implemented at reasonably low cost.


As materials move through a cooling coil, heat exchange occurs. Heat is lost through the surface area of the coil, making the contents colder. The amount of heat lost depends on the length of the coil; just as people try to keep hot water pipes short to prevent heat loss between the water heater and the end source, people can make cooling coils extremely long to promote heat loss. The coiled design allows for a long of surface area for heat exchange in a relatively confined space, as the tubing does not have to be stretched out.

Depending on how a system is designed, materials may be actively pumped through a cooling coil or the system may take advantage of the coil design to pull materials through. In a pressurized system, the differences in density between cold and hot materials drive the circulation of materials through the cooling coil, keeping up a steady flow. The temperature never fully stabilizes, as new hot materials always enter one end while the cooled materials leave the other.

People can use an array of cooling coils to make a space get colder even faster. Coils can also be wrapped around components that must be kept chilled. These components are positioned in the area of the coil where the right temperature is reached, and the material inside the coil circulates freely to provide cooling.

Proper maintenance of cooling coils is critical. They can become fouled over time, reducing the total circulation and making it harder to reach the desired temperature. Corrosion can also become a problem, as it may eat through the coil and create a leak. Many substances used as refrigerants inside cooling coils are toxic and can pose a health hazard if they are inadvertently released. Other concerns can include wear around the sites of joints, creating a leak in a cooling coil, as well as a potential reduction in pressure inside the cooling system that may cause it to stop functioning correctly.

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Discussion Comments


I guess that the radiator I have in my apartment is really just a cooling coil where you are trying to collect the heat rather than cool the liquid. Hot water is pumped through the radiator, the heat is transferred from the liquid, through the metal and into the air and then my apartment is warm and comfortable.


I used to work in a factory that made engine parts for riding lawnmowers. We had all kinds of machinery going at all times and a lot of them utilized cooling coils to cut down on the heat.

I remember once that a cooling coil broke while it had burning hot fluid being pumped through it. The liquid went spewing everywhere. Luckily no one was hurt, it would have been really easy for someone to get burned, but the factory did have to shut down for an entire day. There was a lot to clean up and without that coil it was literally impossible to operate the factory. These coils are more important than people realize.


A lot of people will be familiar with the idea of cooling coils from the radiators inside their cars. If you pop the hood the radiator is right at the front of the engine, it should be what you see when you look straight down.

Radiators work like this: Coolant is pumped throughout the engine to keep it cool while it is running. This fluid return to the radiator superheated. It is then pumped through an intricate series of coils insider the radiator so that the heat can be dissipated. The process is made easier because cool air from the grill on your car blows over the radiator tubes to help cut down on the heat. That is really all there is to it but without this crucial engine component you car wouldn't be able to go much farther than a mile.


A cooling coil example is an example of a really beautifully simple machine. It relies on the most basic of scientific principles and yet it works so effectively.

The principle is really no different than allowing your food to cool. If your food is densely packed and you begin eating immediately it will be really hot. If it spread out to maximize surface area and allowed to cool for a few minutes it will be an acceptable temperature. This simple idea has been applied to thousands of industrial processes to great effect. This is another fine example of human ingenuity.

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