Refrigerators, in some ways, have changed quite a bit since 1835, when the “father of the refrigerator” (Jacob Perkins) received a patent for a vapor-compression cycle. While modern refrigerators certainly have more features and capabilities, many of the essential components and functions have amazingly stayed the same. The essential function of refrigerators is to use the evaporation of a liquid (refrigerant) to absorb heat. The main working parts of a refrigerator include: a compressor, a condenser, an evaporator, an expansion valve, and refrigerant.

Main Working Parts of a Refrigerator


Refrigerant is truly the lifeblood of a refrigerator. It starts in the form of a gas, then a liquid, and back to a gas as it cycles through the refrigerator’s parts. This is the process that cools the refrigerator. In the early stages of refrigerator technology, toxic gases such as ammonia were used as refrigerant. That changed in the 1930’s, when manufacturers began using freon instead. Freon was used for many decades until recent discoveries by scientists found it was harmful to the Earth’s environment. Most modern refrigerators now use a compound called HFC 134a.


The refrigerator cooling process begins in the compressor. A motor powers the compressor, which increases the temperature and pressure of the gas (refrigerant) and sends it along to the condenser. The compressor is typically found along the bottom of the refrigerator, towards the back. The exception is with built-in refrigerators, which usually place the compressor(s) on top.


The condenser is where the refrigerant liquefies. The condenser receives the hot vapors, which are cooled down into a liquid. Its distinguishable by its large copper coils, and you can find them along the bottom or at the back of your unit.

Expansion Valve (Or Capillary Tube)

This cooling process then shifts to the expansion valve, which is a thin set of copper tubes. The expansion valve lowers the liquid refrigerant’s temperature and pressure dramatically, causing about half of it to evaporate. This refrigerant repeatedly evaporating at extremely low temperatures is what creates the cool temperatures inside your refrigerator and/or freezer.


The evaporator is where the cooling process ends and begins the process of the next cycle. It takes the remaining refrigerant liquid and turns it back into a vapor, which the compressor takes to start it all over again.