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Freezing solutions

Co2 or Ammonia Freezing System – what to choose?

The choice between using CO2 or Ammonia as the refrigerant in your freezing system can be challenging. The subject is very elaborate and always requires an in-depth dialogue with Carsoe and third-party consultants.

In this article, we have gathered a short pros and cons list for each method to give you an initial idea of the difference between the two systems.

To help us, we have asked Per Skærbæk Nielsen to weigh-in. Per is the owner of Cool Partners, who has advised companies on industrial refrigeration systems for more than 25 years.


When considering Co2 versus Ammonia it is important to consider the whole system and setup.

Outside factors such as climate and experienced service provides in the area should also impacts your decision.

- Per Skærbæk Nielsen

Co2 Freezing

The Co2 freezing method is relatively new on the market. It is said to be the environmental choice as it is a natural material. Co2 freezing can be very efficient with a high capacity for large fillings.

"When choosing a Co2 system it is very important to find a good and experience refrigeration partner to design the system as well as experienced service technicians for regular maintenance," Per Skærbæk Nielsen says.

Co2 Freezing


  • Can run down to -50°C.
  • Good for limited space.
  • Allows for smaller (and cheaper) valve sizes.
  • Required less plates due to quicker freezing.
  • A well-designed system can result in cost-effective service and maintenance.

Co2 Freezing


  • More complicated
  • Higher costs in establishing refrigeration plant.
  • Less efficient means higher running costs (electrical energy vs thermal energy). Should be evaluated on each case.
  • Difficult to design and setup. Important to choose an experienced refrigeration company.

Ammonia Freezing

“Ammonia is the most common freezing system and has been used for many years across the world,” Per Skærbæk Nielsen says. It is well-tested and well-known which means that experienced and competent refrigeration partners are easier to find.

If space is plentiful, it is considered more efficient to have more freezers running at a warmer temperature (on all refrigerants) as this increases overall efficiency and reduces electrical consumption per kg frozen product.

Ammonia Freezing


  • Cheaper overall system.
  • Well-known system.
  • More simple design making it easier to adjust and maintain.

Ammonia Freezing


  • Big impact if a leak happens.
  • Requires more freezers to achieve the same freezing capacity.
  • Large fillings may result in increased safe requirements, depending on local regulation.

These are some of the points to consider when choosing your freezer setup. Make sure to consult with refrigeration partners to determine, that you are choosing the best decision for your production facilities.

Remember that size of the consulting/contracting company does not always equal the depth of a company’s knowledge. We can supply recommendations for contractors and recommend third party consultants that can represent you independently. They are the experts on the refrigeration setup. We are the experts on designing the freezer.

Related products

We provide the best freezing solutions on the market, fitted to your exact needs. Advanced, efficient and fast freezing is key. 


Our talented employees will be happy to assist you with any inquiries about our products or to discuss the best solution for your company. 

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