How Does A Refrigeration System Work?

Commercial refrigeration is essential for businesses that need to keep products fresh. But how does a refrigeration system work?

Commercial refrigeration is essential for businesses that need to keep products fresh. Heat within ingredients needs to be removed and a controlled temperature maintained in order to prevent food, or other sensitive products, spoiling. It also keeps refreshments cool.

Bacteria multiplies much more slowly at cool temperatures. The refrigeration system creates a cool environment for a business.

Refrigeration uses a scientific principle as the basis for its cooling effect. The Second Law Of Thermodynamics tells us how. When objects of differing temperature are brought together, the heat will travel from the warmer to the cooler object.

How does this work with refrigeration? Well, a refrigerant (in the form of liquid or gas) will pass through the refrigerator’ storage areas, collecting the higher temperature. The refrigerant then passes outside the unit, where it releases the heat into the air.

Refrigerants (or coolants) have very low boiling points (around -20 degrees)

So while the human ear listens to a “hum” in the refrigerator, here’s what is going on “behind-the-scenes” of the appliance…


  • The coolant (a pressurised liquid) enters an expansion valve at the top of the refrigerator.


  • The drop in pressure causes the refrigerant to cool and expand.
  • As expansion takes place, the liquid starts to evaporate to become a gas.
  • The refrigerant follows a path of small pipes, normally on the back of the cabinet.
  • Now fully in the form of gas, the coolant collects heat from the refrigerator’s contents and air inside the cabinet.
  • As it leaves the refrigerator cabinet, this gas enters a compressor.
  • The compressor squeezes the gas under high pressure, it becomes a hot gas.
  • The refrigerant now enters a route of thin pipes (a coil) on the outside of the cabinet.
  • Heat is released as the gas passes through this coil.
  • The refrigerant returns to its liquid state as it reaches the end of these pipes.
  • The whole cycle starts again.


If the hum of the refrigeration system stops, don’t panic. This is unlikely to be a sign that the unit has failed. Refrigerators have energy saving thermostats. These are normally inside the cabinet, but behind an interior wall. A connected probe will sense when the temperature drops below the target and cut power to the compressor.

Cooling the contents of a refrigerator isn’t a rapid process. The products inside most cabinets, even the solid food, have a high water content. Water contains the lightest of molecules and these take energy and time to cool down (or heat up).

Don’t be fooled into believing that opening a refrigerator will reduce the temperature of a kitchen either. It will very quickly have the effect of simple moving heat from one area of the kitchen to another.

Refrigeration gases (if released into the atmosphere) have long been considered contributors to the damage caused to the earth’s ozone layer. The refrigeration industry is constantly working hard to become more ecologically friendly.

Commercial refrigeration experts, such as R.Perkins & Sons can provide an analysis of your current equipment. Legislation is constantly evolving, being aware of your which refrigerant your equipment uses can avoid inadvertently flouting any regulations.

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