Ammonia (R-717) vs. CO2 (R-744) Refrigeration Systems

A key characteristic of creating an industrial refrigeration system is the refrigerant of choice. CO2 is slightly less efficient than ammonia but this difference is less noticeable at lower temperatures. Ammonia refrigerants are less expensive initially, but they come with the risk of a toxic chemical leak. CO2 refrigerant systems have a greater initial cost, but the equipment takes up significantly less space than ammonia systems. Discovery Designs Refrigeration creates custom refrigeration systems with either CO2 or ammonia depending on your specific needs.

Both CO2 and ammonia have been used as industrial refrigerants in a whole host of different industries since the 1800s. These refrigerants are considered “natural” refrigerants and are thought to be environmentally friendly alternatives to standard Freon cooling systems. They release fewer HCFC’s into the atmosphere, thereby reducing the effect on the ozone layer.


  1.   Meticulous design & installation
  2.   Precision temperature control
  3.   Uninterrupted high performance
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Ammonia (R-717) Refrigeration Systems 

Ammonia consists of nitrogen and hydrogen. Ammonia used in refrigeration is called anhydrous ammonia because it does not contain water. Conserving the purity of ammonia is the essential task of an ammonia refrigeration system.

Ammonia R-717 vs CO2 R-744 Refrigeration systems

Pros of Ammonia Systems:

  • Natural and environmentally friendly
  • Energy efficient
  • Requires smaller pipe sizes
  • Better heat transfer lowers cost
  • Low material price

Cons of Ammonia Systems:

  • A leak could injure or kill someone in rare cases
  • Usually used in warehouses and spaces with less personnel
  • Impacts the environment slightly more than CO2 since ammonia is usually taken from natural gas

CO2 (R-744) Refrigeration Systems

CO2 has been used in refrigerant systems since the 1800s. Over time the industry moved away from CO2 towards synthetic refrigerants like Freon. Now CO2 is gaining popularity again due to the negative environmental impacts of synthetic refrigerants. HFCs (hydrofluorocarbons) are potential accelerants for global warming.

Pros of CO2 Systems:

  • Non-corrosive; nonflammable; low toxicity
  • More efficient at lower temperatures making CO2 more common in facilities with a lot of freezers
  • Less expensive for long-term needs
  • Low potential for decomposition within the system
  • Required equipment takes up less physical space

Cons of CO2 Systems:

  • Greater initial cost compared to ammonia refrigerants
  • Sensitive to water contamination
  • Two-stage compression required for transcritical systems
  • Requires specially designed components & compressors
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Enhancing Local Refrigeration Systems

Discovery Designs Refrigeration works with all parts of your refrigeration system to better serve your purposes and give you your money’s worth to you. We do it all, ensuring one company fully understands and maintains your refrigeration systems.

Inefficiencies in cooling systems cost you money and can be a significant portion of your budget. Discovery Designs Refrigeration designs your system with maximum efficiency in mind, considering your location, the climate, and the system’s use in your facility.

Contact Discovery Designs Refrigeration, LLC to find out more about how our services can benefit your company.

Call Us Today For a Quote! 262-373-6500