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The Refrigeration Cycle, Explained

by Waverly Wilde


We all take our refrigerators for granted. When they work, we don’t have to fuss over them. But how do they work?

You’ve probably never given the inner workings of your refrigerator much thought unless it broke down. Or maybe when it comes time to replace it? That is the beauty of a working fridge. When it works, you don’t have to think about it much.

However, it might be worth thinking about how this appliance works. From stocking up on supplies for a summer BBQ to riding out COVID-19, refrigeration is a huge part of our everyday lives. Not just in your own home but the many perishable foods you consume require refrigeration both with storage but also transportation.

How Does a Fridge Work?

So how does this all work? Well, in short, your refrigerator stores food at an optimal temperature to extend the shelflife and slow down the growth of harmful bacteria (which all food has). The refrigeration cycle works by transferring heat from inside of the unit to the outside using condensation and evaporation.

For example, bacteria could spoil milk in just three hours if it is left out at room temperature. By refrigerating it, it can stay fresh for up to a few weeks. By freezing the milk, you can stop the bacterial growth altogether. It will last for months this way. Eventually, freezer burn plays a role in your food storage.

gallon of cold milk

Refrigeration and freezing are two of the most common forms of food preservation used today.

Before we dive into the mechanics of your refrigerator, here is a fun experiment to help you understand what is happening within your fridge: poor some rubbing alcohol onto your skin. Feel how it gets colder? It chills your skin the same way a fridge chills your food. The alcohol evaporates by absorbing heat from the surface of your skin, making your skin cooler. This is what refrigerant does, explained in detail below.

The Parts of a Refrigerator

The main components of your refrigerator are the following: compressor, condenser, evaporator, expansion valve, and the thermostat. Here is what each one does:

Compressor

This unit is responsible for the circulation of refrigerant throughout the system. It is both a pump and a motor.

Condenser

Located on the back outside wall of the fridge, it helps release the heat absorbed from inside the unit.

Evaporator

Housed on the inside of your refrigerator, it absorbs any heat stored within the unit. This is what reduces the temperature.

Expansion Valve

Refrigerant warmed by the inside of the fridge is carried through tubing which works as an expansion device as it cools the gas back into liquid.

Thermostat

This is what controls the temperature inside the fridge, activating the cooling cycle as needed.

refrigerated food

How Does the Refrigeration Cycle Work?

  1. When the thermostat senses the inside temperature is above the set temperature, it engages the compressor, and the refrigeration cycle begins.
  2. The compressor draws in the liquid refrigerant, pressurizes and condenses it, raising its temperature -- effectively turning it into a gas.
  3. The compressor pushes the gas towards the condenser coils on the exterior. The air is of a lower temperature than the gas, cooling the gas back to a liquid state as the heat is dissipated.
  4. The cooled liquid heads to the evaporator, traveling through the inner coils of the fridge and freezer.
  5. The refrigerant absorbs the hot air from within the fridge, lowering the internal temperature.
  6. The refrigerant then turns back into a gas, returns to the compressor as the cycle starts all over.

And that’s how your refrigerator works. Well, that is how it should work. If it isn’t working, give our appliances experts a call today so we can help you choose one that does.