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.
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.
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.