What Is a Refrigerator Compressor?

A refrigerator compressor is the engine of the cooling system. Larger industrial refrigerators have a compressor above the refrigerator behind a grating while in the smaller household refrigerator it is behind the refrigerator.

The Cooling System

The cooling system consists of the compressor, the internal and external coiled heat exchange tubing, an expansion valve, and the refrigerant gas. The gas used is HFC or tetrafluoroethane.

The basic concept depends on the cooling effect of evaporation. For a liquid to evaporate it needs to absorb heat. This is what cools your skin on a hot day. Your sweat absorbs the heat from your skin and turns into water vapor, which cools you as it leaves your skin.

The liquid gas used in refrigerators can only evaporate at a very low temperatures and this is why a refrigerator can freeze.

How a Compressor Works

The compressor motor forces the gas into the exterior coiled tubes causing an increase in pressure and temperature. Via these coils the gas releases the heat into the atmosphere. The refrigerant cools and condenses into a liquid, which is squeezed through the expansion valve into a low pressure area caused by the suction from the compressor. As the liquid suddenly expands it evaporates, absorbing heat and causing a severe drop in temperature. The inner coiled tubes allow the refrigerant to absorb heat making the inside of the fridge very cold. The compressor then pressurizes the gas and it goes through the tubing again.

Temperature Control

The internal thermometer of the fridge, a thermocouple monitors the temperature and switches off the motor when it is cold enough.