How is ammonia used in refrigeration?

To answer this question, we must first look into why ammonia is used in the first place. Back when refrigeration was needing more synthetic refrigerants in the 20^th century, chlorofluorocarbons were more commonplace or refrigerants like Freon-12. These synthetic refrigerants were used until it was found that they were dangerous to the environment, that’s when ammonia began to be implemented.

To use ammonia as a refrigerant it must be pure, AKA refrigerant grade anhydrous ammonia. This ammonia must be at least 99.95% pure and cannot have a water content above 33 ppm or an oil content above 2ppm. These specifics are what preserve the concentrated ammonia as well as keep the refrigeration system working at its best. The levels of water and oil that can be present exist because of potential hazards that cause the system to malfunction. If there is too much water then the pipe will freeze and rupture and if there is too much oil then the system will have to work harder than necessary, as a result it strains the components. If there is too much oxygen, then the pipes can suffer from corrosion and subsequently lead to cracked steel.

Who uses ammonia as a refrigerant?

Industrial ammonia refrigeration systems are used by large-scale operations, for example ones that produce food. The reason companies use this kind of system rather than other refrigerants is that it’s actually more cost effective than other alternatives. On top of that, it is also eco-friendly since it doesn’t damage the ozone layer like other CFC’s. However, this doesn’t mean you can use it for your own refrigerator in your kitchen! You can’t buy it anymore as the fumes are considered to be too toxic in case of an accidental release.

The nice thing about using ammonia for refrigeration is that its physical properties make it very efficient for large cooling operations.

With a natural boiling point of -28 degrees Fahrenheit, anhydrous ammonia is really efficient at keeping things cold.
The machine itself costs less money since ammonia pipes are smaller.
The refrigerant breaks down fast in the environment unlike CFCs so it’s environmentally friendly.
Anhydrous ammonia is less expensive than other CFCs.
Accidental release is easy to identify as well because of its sharp smell.