In our blog series, we have covered what a refrigerant is and the types that have been developed and used, so we want to answer another question we are sometimes asked – how does the refrigerant work? This blog will answer the question and without getting bogged down in jargon and scientific speak!

A bit of history!

All modern refrigeration methods had to start somewhere, and a couple of notable men had a vision for the idea. These men took it forward and developed it into the start of the modern units we have both in our homes and that EJM install on an industrial scale. Jacob Perkins was an American, but it was in Great Britain he had his first patent issued for a mechanical refrigeration unit, way back in 1834, but better was to come.

The other notable person that went on to be well-known in the frozen food circles, was Clarence Birdseye. Back in the early 1920s, Birdseye was an inventor and his invention to quickly freeze fish was such a success, he made bigger and better versions. These versions made freezing fish, meat, fruit, and vegetables, safe and quick. Think of fish fingers today and Birdseye springs to mind!

Why is refrigeration important?

For many people refrigeration is something you do to milk etc. but refrigerants are used for so much more than foodstuffs. The pharmacy industry relies on keeping so many medicines, vaccinations, and other items cold – without it there would be a bigger health problem globally. How many offices and buildings have air conditioning? If there were no refrigerants this would not be possible. On the healthcare side, refrigerants are vital to many areas in hospitals including mortuaries.

Science of refrigeration.

As you can imagine there are many types of refrigeration and units available, in all shapes and sizes. When it comes down to the science the basic principles all still apply.

Refrigeration has one job – to remove heat from an area and put it in another area. To do this the chosen refrigerant is pumped through a closed system to remove heat and discharges it elsewhere.  There are two sides to the system, a low-pressure side, and a high-pressure side.

The components used for refrigeration.

As you can imagine there are hundreds of components and pieces of equipment that make up an industrial refrigeration plant, but the major components are used in some form in every type of cooling system. The main components used are:

  • A compressor.
  • A condenser.
  • An evaporator.

And of course, the refrigerant itself – which can be several types of chemical, or a natural refrigerant, as our preferred one, ammonia. But what do these components do? A look at a simple air-conditioning system can help lay it out.


There are many types of compressors including, reciprocating, centrifugal, screw type, rotary, and scroll. No matter which type, they all do one main job – pump refrigerant around the system, this is where the high-pressure side comes into play. The refrigerant at this stage is a gas and pushing through the system makes the at high pressure means the compressor itself can start to generate high temperatures.

This means the compressor also needs to dispose of this heat so the system has a safe working temperature. There are various ways this happens, including using cooling fins as the compressor runs.

Condensers and expansion.

The next stage is where the hot gas enters is a condenser, this effectively cools the hot gas using processes such as cooling metal fins and a fan speeding up the process. When this happens the gas cools enough to turn it to a hot liquid. It then can move to an expansion unit, where it cools further and makes it go from high pressure to low pressure.


This is the final stage before the cycle starts again. The job of an evaporator is to process the last of the heat and cool it to a stage where it evaporates using special coils, blowing cooled air back into the ductwork.

The whole process is about the refrigerant absorbing heat, moving it outside or away from the area being cooled, then returning to start the process again as a very simplified version!

This, of course, is just one of many processes, industrial refrigeration also uses a similar principle on a much larger scale.

There is quite a bit to a refrigerant working efficiently and of course safely, meeting legislation and guidelines. There are many different scales and sizes of units from small plants, to huge installations. As you can imagine there are also many manufacturers of the equipment produced to make the refrigerants work.

At EJM we service and install many types of equipment, from compressors to all the ductwork. If you need more information or would like to discuss how we can make refrigerants work for your business, please get in touch – our friendly team is here to take your call or offer advice.