Is Ammonia the Best Refrigerant? The Cold Hard Facts
January 26th, 2023
When considering which refrigerant to use in a new refrigeration process, it is important to compare the advantages of the readily available options to see which will be the best fit for your and process. In particular, today we’ll discuss the benefits of using ammonia refrigerant over others that are available– such as traditional Chlorofluorocarbons (CFCs), Hydrochlorofluorocarbons (HCFCs), and other synthetic refrigerants. Ammonia refrigeration is commonly used in facilities with large-scale refrigeration needs, such as food/beverage manufacturing facilities, cold storage warehouses, and petrochemical plants.
Ammonia has three advantages over other refrigerants: equipment is less expensive to purchase and install (not to mention ammonia chemical is cheaper than most other refrigerants), ammonia as a refrigerant is more efficient than other options, and it has low or no negative environmental impact. Each of these is discussed in detail below.
1. Cost/Availability of Equipment and Chemical
Ammonia refrigeration equipment allows for narrower process piping than that for other refrigerants, which is cheaper to make and easier to get. This type of refrigeration equipment also typically costs 10-20% less than equipment using CFCs or HCFCs – not to mention ammonia refrigeration equipment is widely and readily available in the U.S. from a number of manufacturers. Additionally, the average cost per pound of ammonia is significantly less than CFCs, HCFCs, or other synthetic refrigerants – by up to 50% or more! Ammonia is also far more readily available than most other traditional refrigerants in today’s world.
2. Efficiency of Ammonia Refrigeration vs. CFCs and HCFCs
At capacity, ammonia refrigeration systems are estimated to be up to 20% more efficient than alternative refrigerant options – particularly CFCs and HCFCs. There are two factors that contribute to ammonia’s superior efficiency in large-scale refrigeration process.
- Thermodynamic properties: When used in refrigeration, ammonia is typically stored under high pressure (to keep the chemical in liquid phase) and will immediately vaporize when pressure is reduced. Ammonia uses heat from its immediate surroundings to produce the phase change from liquid to vapor, substantially cooling the surrounding area as the chemical evaporates.
- Cost efficiency: In addition to ammonia chemical being cheaper than other refrigerants, studies have also shown that ammonia refrigeration operates with lower overall electricity costs – and is up to 10% more efficient with electricity than CFCs.
3. Environmental Impact
Throughout the 20th century, people considered CFCs to be completely harmless. Their stability made them a popular choice as refrigerants. However, more recent research has revealed the negative impact that CFCs have on the environment – the Ozone layer in particular. Ammonia is not a contributor to ozone depletion, greenhouse effect or global warming – making it an environmentally friendly refrigerant. Ammonia has not been identified to have any cumulative effects on the environment and a very limited atmospheric lifetime once introduced. Because of its short lifetime in the atmosphere, ammonia is considered to be biodegradable – particularly relative to CFCs and HCFCs.
Other Considerations
Industrial ammonia refrigeration systems do require prior planning to help mitigate and/or eliminate potential health and safety hazards. The biggest risk that may occur is a chemical leak, which is both a health and safety hazard. The most common health concerns with ammonia are skin burns and difficulty breathing, as well as death only in the rarest cases. Leaks most commonly occur during the unloading and loading of ammonia; however, careful and considerate design and diligent training of employees can go a long way towards preventing these leaks.
Additionally, ammonia is a chemical that is regulated by both OSHA (via the Process Safety Management [PSM] Standard, 29 CFR 1910.119) and the EPA (via the Risk Management Plan [RMP] Rule, 40 CFR Part 68) in any quantity of 10,000 pounds or greater – requiring that certain safeguards and policy are implemented at the site using the chemical to minimize the chemical-related hazards of an unintended release.
That’s where HRP comes in – with the OSHA PSM and EPA RMP program implementation and compliance. If you are considering the installation of a new ammonia refrigeration process that will include a quantity of ammonia that exceeds the 10,000-lb threshold quantity for inclusion in the program, be sure to reach out to the experts at HRP. We have the knowledge and the know-how to assist you in the installation, program implementation, and safe operation of your future ammonia refrigeration process.
Justin Evans, Project Manager at HRP Associates, Inc.
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