What Are the Main Working Parts of a Refrigerator?

A fridge is the go-to place to hold your favorite condiments, cuts of meat and the occasional cake. The humming appliance in home kitchens, offices and hotel rooms around the country continuously transfer heat to keep your favorite foods at the correct temperature. Understanding how they operate and what makes them tick can help you fix a broken fridge – or at least have a better appreciation for this relatively new technology.

Refrigerator With Fruits And Vegetables
credit: AndreyPopov/iStock/GettyImages
What Are the Main Working Parts of a Refrigerator?

History of Refrigeration

Jacob Perkins received a patent in 1835 for a vapor-compression cycle, making him the father of the modern day refrigerator. The cycle used the evaporation of liquid – or refrigerant – to absorb the heat of the motor. They have evolved quite a bit from the singular cold box of way-back-then but are essentially the same in how they function. The compressor, evaporator, expansion valve, condenser and refrigerant still work in much the same way as they did nearly 200 years ago.

Main Parts to Know

The lifeblood of the fridge is the refrigerant, which runs through most of the main components. The compressor, condenser, evaporator and expansion valve work together to turn the refrigerant from its original gas form into a liquid and then into vapors. The cool running of a refrigerator relies on the harmonious relationship of all of its parts. If one component breaks down, the entire process is halted.

The Process

At the bottom and back of the fridge lies the compressor, which is where it all begins. The motor revs up the compressor to increase the temperature and pressure the refrigerant. The refrigerant is sent to the condenser. Built-in refrigerator systems often carry the compressor on top for ease of access.

The refrigerant is HFC 134a compound that replaced freon. It starts as a gas that turns to a cool liquid and back to a gas through the process. The condenser has large copper coils and is usually at the back of the fridge. It liquefies the refrigerant and takes in the heated vapors, then cools the vapors into a liquid. The evaporator takes the refrigerant liquid, vaporizes it and returns it to the compressor. The thinner copper tube set is the expansion valve, which lowers the temperature of the liquid refrigerant and decreases the pressure. This causes the refrigerant to be reduced by nearly half due to evaporation. The repeated evaporation at extremely low temperatures is how your fridge can keep its steady cool all year round.