The Basics of Commercial Refrigeration

At Parts Town, we love parts. And so it goes we love the machines those parts live in. Occasionally we like to look at some of the machines our parts serve and learn a bit more about them. Previously, we learned about food warmers. Today we’ll be talking about the refrigerator.

Recently we looked at the history of the refrigerator. Refrigeration was a game-changer for human civilization, making food storage easy and affordable for everyone. But how exactly does a refrigerator work, and are there ways to make them work better? Let’s learn about refrigeration in the commercial kitchen today at Parts Town…

The Basics

A refrigerator removes heat from the food inside. This keeps the food cold.

Class dismissed.

Alright, it’s a bit more complicated than that, at least in terms of how it’s really done. But that’s the goal of every refrigerator – take the heat away. How they accomplish that has varied over the years.

Two Principles

There are two key principles that make refrigeration work:

1. Gases cool when they expand.

2. If two objects are different temperatures and come close enough, the hotter object cools and the cooler object warms. You might remember this from High School as the 2nd Law of Thermodynamics.

So … how does that cool my food?

We are getting there, friend!

Your favorite refrigerator manufacturers like Delfield or Norlake use these two principles to make sure that food in your commercial kitchen stays cool, where it can be preserved and used later.

In order to do this, refrigerators used to use a chemical referred to as a Freon, or Chloro-Flouro-Carbon, or perhaps most commonly, CFC. Unfortunately, it turns out CFC can damage the environment when it leaks into the air, so a modern refrigeration unit won’t use that anymore.

A modern unit uses tetrafluoroethane (which we’ll call HFC). This gas turns into a liquid when it reaches -15.9 degrees Fahrenheit.

Let’s take a look at the process of cooling:

1. First, the HFC is squeezed by the motor and compressor of the fridge. Compressing the gas heats it up, and it moves through the coils in the refrigerator – losing some of the heat to the air in the room due to the second law of thermodynamics mentioned earlier.

2. The HFC cools, and while it is under high pressure, changes to a liquid. The liquid goes through a valve, and encounters an area of low pressure.

3. When the HFC goes through the area of low pressure, it boils and changes into a gas – in a process called vaporizing. The HFC continues to travel through the coils, going through the freezer and the refrigerator, pulling the heat out of the area. And there you have it – a cold fridge.

4. At the end of the journey, the compressor receives the cold gas, and the process begins again.

Refrigerators may use slightly different designs and technologies to achieve the effect, but they all follow the same principle.

We hope you’ve learned a little about how that big cold box in the corner actually operates. And remember – if you need help repairing or diagnosing the problem with your fridge, Parts Town can help. Thanks for reading!