What refrigerant was reintroduced in the 1980s as a replacement for large-scale refrigeration systems?

The refrigerant that was reintroduced in the 1980s as a replacement for large-scale refrigeration systems is ammonia. Ammonia is known for its effectiveness as a refrigerant due to its high efficiency and low environmental impact compared to other synthetic refrigerants.

In the 1980s, there was a significant shift in the refrigeration industry due to growing concerns over ozone depletion linked to chlorofluorocarbons (CFCs). Therefore, ammonia gained popularity as it does not contribute to ozone layer destruction. It is a natural refrigerant that has been used for many years, particularly in industrial applications, where its properties allow it to perform exceptionally well.

The other refrigerants mentioned, while they may have specific applications, do not fit the context of being a primary large-scale alternative from that era. Freon, another term for CFCs, was being phased out during that time due to its harmful effects on the environment. Propane, while a viable refrigerant, is more commonly used in smaller systems, and chlorofluorocarbons were the very substances being replaced due to environmental concerns.