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What is a Refrigerant Compressor?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

A refrigerant compressor is a component of a refrigerator which is designed to compress the refrigerant used to cool the refrigerator. Compressors can also be found on other devices which are designed to be used for cooling. The refrigerant compressor is part of a closed system which keeps the refrigerant moving in a loop; in some systems, the system is on continuously to maintain a very stable temperature, while in others, it may cycle on and off.

The way in which a refrigeration system works is actually rather interesting. It starts with a refrigerant, a fluid with some unique properties which allow it to transfer heat and cold very efficiently. Refrigerants are used in fridges, freezers, and air conditioning systems, and a number of different chemicals are used. Historically, the chemicals used were dangerous for the environment, which posed a problem when they leaked or a refrigeration system was discarded. Today, refrigerants are designated as environmentally friendly, and special practices must be used to clear all of the refrigerant before a refrigeration system can be thrown away.

Refrigerants are what keep refrigerators cold.
Refrigerants are what keep refrigerators cold.

In the compressor, a vaporized refrigerant is subjected to high pressure, which causes the vapor to return to a liquid state as its temperature rises. The fluid refrigerant, at this point very warm, moves through a series of condenser coils on the outside of the device, which allows it to dissipate heat. Then, the fluid hits an expansion valve. One side of the expansion valve has a lower pressure, which forces the refrigerant to return to a vaporous state. As the refrigerant vaporizes inside the system, it also pulls out heat, causing the air inside the refrigerator to cool down. The vapor moves through a series of coils until it hits the refrigerant compressor and the cycle starts all over again.

A power outage will shut down the compressor, causing the foods in the refrigerator to spoil.
A power outage will shut down the compressor, causing the foods in the refrigerator to spoil.

Each part of the refrigeration system is important, but the refrigerant compressor is especially critical. This is the part of the system which requires some form of energy to compress the vaporized refrigerant. When the power fails or the compressor experiences a problem, the whole system shuts down, allowing the temperature inside the refrigerator to rise. Compressors have to work very hard, and they can eventually fail.

In some cases, it is possible to repair a refrigerant compressor which has broken down. In other instances, it may be necessary to replace the compressor. Either task should be performed by a technician who is certified to work on cooling systems.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a AboutMechanics researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a AboutMechanics researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

anon332312

Why is it that a refrigerator compressors are so expensive to replace or repair? Somehow, it doesn't make sense to me that it is cheaper just to replace the refrigerator than to repair the compressor!

cardsfan27

Air conditioning uses the same principles as a refrigerator, right? I know in a car, every so often you have to have the air conditioner coolant replaced or refilled. Is the same thing ever true for a refrigerator?

I've never had a problem with my fridge running low on coolant. Does it ever loose any over its lifetime? If not, then why do cars loose their coolant? Could there be different coolant or refrigeration compressor types that might make the difference?

titans62

I just had to replace my refrigerator because the compressor went out on it. Luckily, it was still under warranty, or the price could have been outrageous. The cost of ordering the compressor and having it replaced would have been at least $700 dollars. At that rate, it was cheaper for the store where I bought it to replace the unit instead of fixing it.

I think that I just drew the short straw and ended up with a faulty compressor. I know people who have had the same refrigerator for over a decade and haven't had to have any repairs. I doubt they clean the coils, either.

I'm just wondering, but are there two different compressors in a refrigerator, one for the freezer and one for the main section? Otherwise, how does the freezer stay colder?

TreeMan

@matthewc23 - There is nothing that I know of you can do to the compressor itself, but there are a few things you can do to make it work a little less.

The refrigerator is probably the most forgotten part of spring cleaning, but is still very important. At least once a year, it is recommended that you pull out the fridge and clean the condenser coils to remove any dust that has built up. You can use a wire brush if it is really bad. The condenser coils are where the heat exchange described in the article actually happens. The dirtier they are, the more work the compressor has to do.

Besides that, run the refrigerator at the highest temperature you can while still keeping your food cold enough. This will save you energy, too!

A compressor is the most expensive part of a fridge, and should last many, many years if you take care of it.

matthewc23

I always wondered how a refrigerator worked. That was a good and simple explanation.

It sounds like the refrigeration compressor is one of the most important parts of the system. Is there any way that you can help take care of it to stop it from wearing out sooner? If you don't perform any maintenance, how long will a compressor usually last?

anon86641

was a very helpful note. great going you guys.

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    • Refrigerants are what keep refrigerators cold.
      By: Piotr Pawinski
      Refrigerants are what keep refrigerators cold.
    • A power outage will shut down the compressor, causing the foods in the refrigerator to spoil.
      By: auremar
      A power outage will shut down the compressor, causing the foods in the refrigerator to spoil.
    • Because they often develop small leaks, air conditioners usually require refrigerant charging at some point.
      By: Cyril Comtat
      Because they often develop small leaks, air conditioners usually require refrigerant charging at some point.