Classification of Refrigeration Systems: Direct and Indirect

Refrigeration systems have multiple applications: food preservation, equipment cooling, space cooling, industrial purposes…

Having such differentiated functions, the refrigeration systems indicated for one or another case is specific for that purpose and adapted to the needs sought.

To find out which cooling system is indicated for each case, we will divide them into two groups: direct and indirect cooling systems.

Direct and Indirect Cooling Systems

Direct refrigeration systems are those in which the condensed and compressed refrigerant gas is distributed to remote units (evaporators) from the engine room.

On the other hand, indirect refrigeration systems are those in which the refrigerant gas is confined in the area where the cold is generated. From there, the cooling power is transferred to an intermediate fluid through the exchanger or evaporator. So, this system is made up of two circuits: one of them generates the refrigerant and the other distributes it.

Which Cooling System To Choose, Direct Or Indirect?

Direct refrigeration is installed less and less, since its installation is more expensive and, in addition, it implies a significant increase in the refrigerant charge. It is, therefore, much more common to find indirect cooling systems. Why? We tell you its main advantages.

Advantages of installing an indirect cooling system

  • It limits the risks associated with refrigerant leaks, which in turn reduces risks to people and the environment and minimizes production losses.
  • Reduction of the refrigerant gas charge compared to direct systems.
  • It opens the possibility of using natural refrigerants such as R-717 and hydrocarbons and low-GWP HFCs.
  • The possibility of creating compact systems with the possibility of operating tests that do not require on-site refrigeration connections or long assembly times.
  • Reduces the size of the engine room and sometimes eliminates it.
  • Possibility of accumulating cooling energy for industries such as dairy or brewing.

Where Is Indirect Industrial Refrigeration Applied?

Commercial Refrigeration

Commercial refrigeration refers to the design, installation, and maintenance of refrigeration units that are located in commercial establishments to store, display or maintain food or perishable items in optimal conditions.

We can find this type of refrigeration in various ways, but the most common is the refrigerator cabinet. This exposes the perishable product and can be opened, to the air with an air curtain or closed with an easy opening system. The temperature must range between +44.6/50ºF (fruits and vegetables) and -0.4/68ºF (frozen).

The cooling system works with direct refrigerant expansion or an indirect glycol cooling system.

Industrial Refrigeration

Industrial refrigeration is the application of high, medium, low, and very low-temperature refrigeration (up to -76ºF) with very specific objectives within the industrial field, key in the activity carried out.

The machinery used is, therefore, much larger and more powerful than that of commercial refrigeration, since it plays a vital role in a long and specialized process. This means, therefore, that the level of security required to maintain them is also much higher.

Common Industrial Applications:

  • Ice plants.
  • Warehouses for perishable food.
  • Oil refineries.
  • Chemical plants…


If you need an expert opinion on what type of refrigeration to implement or if you need  Freezer Building Construction, AWIC is the perfect place to be. They are professionals in the walk-in cooler industry and will help you find a suitable refrigeration unit for your business.