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  4. How Does a Refrigerator Work? The Refrigeration Cycle Explained.
reaching into refrigerator
reaching into refrigerator

How Does a Refrigerator Work? The Refrigeration Cycle Explained.

The refrigerator is our hardest-working kitchen appliance and one that we often take for granted. When we get hungry or thirsty, we open the door, reach in, and grab something cold but rarely think about how a refrigerator actually works or what keeps it running.

We know it’s not magic, but it's definitely a convenience that we rely on daily.  

Knowing how a refrigeration cycle works helps you care for and maintain your appliance, spot signs of trouble, and communicate with a contractor when a component needs attention. The more you know, the more prepared you’ll be! 

The refrigeration process is a cycle that repeats itself again and again. In fact, the appliance gets its name from the refrigerant chemical used to create the cool interior environment. Refrigerants, such as pure ammonia, boil at very low temperatures, which is where the process begins. 

Here is the Refrigeration Cycle Explained:


1. The Compressor Heats the Refrigerant

Your refrigerator’s compressor does just what its name implies—it compresses the refrigerant gas to heat it. How a refrigerator compressor works is by pulling in cool refrigerant gas and heating it by compressing it. As you’ll see, the compressor also controls the refrigerant flow. 

2. The Refrigerator Coils Turn Hot Refrigerant Gas Into a Liquid 

Most refrigerators have coils on the outside and inside of the unit that act as the refrigeration cooling system. The condenser coils on the outside (often on the back) allow the hot refrigerant gas to cool as it exits and pressurizes into liquid form. For example, ammonia gas would condense into ammonia liquid.  

3. The Refrigerant Flows Through the Expansion Valve and Evaporates Into a Gas

Now under high pressure, the refrigerant liquid flows through the expansion valve to low pressure via the interior evaporation coils. When this happens, the liquid boils and turns into a vapor or gas, dropping temperature. This refrigeration cooling cycle is what makes the refrigerator interior cold.  

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4. The Compressor Pulls Up the Gas and the Cycle Starts Again 

The refrigerator is one hard working appliance! And now that you’ve read these steps, you may be wondering how long your refrigerator runs during a typical day? That depends on the age of your fridge, as newer refrigerators can run for up to 90% of the time. However, your refrigerator does not—and should not—run constantly. Every 12 to 15 hours, the refrigeration defrost cycle should begin, which uses a defrost heater to melt any frost that has accumulated on the evaporator coils. Once the defrost cycle is complete, the refrigeration cycle will begin again. 

The refrigeration system is a little different for commercial properties like grocery stores and restaurants. These units typically use a large-scale refrigeration rack system with a different setup than your home kitchen refrigerator. 

How to Properly Maintain Your Refrigerator 

Now that you know how the refrigerator cycle works, it’s easy to see how proper refrigerator maintenance plays an important role in helping your appliance run smoothly and stay energy efficient. Here are some energy-saving tips to help your fridge do its job right.

  • Inspect the door seal gaskets regularly to help ensure that the cool gas stays inside the unit, where it’s needed to cool the contents. 
  • Clean the refrigerator coils to encourage refrigerant gasses and liquids to flow properly and perform their refrigeration cycle duties. 
  • Set the refrigerator temperature properly (usually between 35 and 38 degrees Fahrenheit) and minimize how often and how long the door is open. This helps keep the interior and your food and drink items cold.
  • It’s also a good idea to avoid storing items when they are very hot, which makes the unit work harder to cool. So, let that hot soup cool down before sticking it in the fridge.
  • It’s better for your refrigeration cooling system to keep your refrigerator well-stocked and full so that the unit doesn’t have to work to cool empty spaces. This is why choosing the right size refrigerator for your household is important. 
  • Keep the interior of the refrigerator clean as an essential part of maintenance as well.

A little knowledge and TLC can help you understand what your refrigerator needs to function at peak efficiency for your household. And when you have the facts about how a refrigerator works, you can feel empowered to do a bit of DIY refrigerator repair.



You may need to contact a trusted refrigerator repair professional to make a repair or to detect a problem with your refrigerator. So, why not let a home warranty from American Home Shield® help you with that? Our home service plans will not only protect your refrigerator but also many other appliances you use every day, such as your dishwasher, clothes washer and dryer, garbage disposal, oven, and more.

If you are an American Home Shield member, all you have to do is place a service request if something doesn’t seem right with your refrigerator, and we’ll send a qualified contractor to your door to assess the issue. As long as your home service plan covers the repair or replacement, we’ll take care of the rest.


AHS assumes no responsibility, and specifically disclaims all liability, for your use of any and all information contained herein.

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