Industrial Refrigerants
Anhydrous ammonia is the most common refrigerant used in industrial refrigeration today and is often referred to as; R-717, ammonia, or NH3. The application of ammonia to refrigeration systems has become universally known as the field of industrial refrigeration.
Ammonia has the distinct advantage of a high latent heat and excellent heat transfer properties. Ammonia is also readily available at an economical cost when compared to other commercial refrigerants. These combined advantages are the principle reasons why ammonia is utilized in large refrigeration systems.
From an environmental viewpoint, ammonia has no ozone depletion or global warming potential and is biodegradable.
Carbon dioxide (CO2 or R-744) has been extensively used in the past. It is undergoing a popular resurgence and has distinct advantages for low temperature applications. One of the benefits of using CO2 in low temperature refrigeration system is the low specific volume of the refrigerant vapor. This has a direct positive impact on the required compressor displacement (ft 3/min or m3/min) and can help to reduce the installed size of the compressor(s).
CO2 is also considered a high-pressure refrigerant. A CO2 refrigeration system that experiences an emergency shutdown or power outage may require additional measures to contain the refrigerant.
The use of CO2 as a refrigerant does not contribute to the greenhouse gas problem as this is simply recovered gas from the atmosphere.
Propane (R-290) or Propylene (R-1270) are two other examples of common refrigerants known as hydrocarbons. These are commonly found in large chemical processing or refinery facilities. While propane and propylene are suitable as refrigerants they are also flammable gases. This restricts their use to facilities where the requirements of specific area classifications such as explosion proof electrical devices are common place.
The refrigerant selected for an industrial refrigeration system should be based on the actual requirements of the cooling process. Some refrigerants offer significant benefits over other refrigerants for specific reasons. Additional criteria may include; safety considerations, operating temperatures, familiarity with the refrigerant and its specific requirements, or ease of integration into existing infrastructure.
