Practical strategies for leveraging ammonia’s strengths while managing safety and regulation.

I’ve written many times in the past on the unique opportunities that ammonia gives as a refrigerant. One of the fascinating things about it is that it is the only substance that has remained in widespread use since it was first introduced as a refrigerant in the 1860s during the era that Jim Calm has described as “whatever works.”

Believe it or not, this is not by accident. Proponents of ammonia have found it to be very efficient, reliable, predictable and safe in use in refrigeration systems. People who use it in industrial refrigeration systems are effectively de-risking their operation, although it is difficult for those unfamiliar with the behavior of ammonia to see how this could possibly be true. Regular readers of this column will have noticed that I am a bit of an ammonia fanboy.

Opponents of ammonia will regularly say “But it is flammable and toxic—it’s not safe.” In both cases the answer is “that depends what you do with it.” It is certainly not true to say that ammonia systems are inherently unsafe. Given the huge amount of ammonia manufactured every year, and the way it is shipped all over the world, it is clear that it has an excellent safety record in refrigeration systems and the wider industrial and agricultural sector.

I was reminded earlier this year, when there was a change of government in the UK after the General Election in July, that I had considerable success designing, building and installing ammonia chillers for various government buildings in the first decade of this century, but that had all stopped with the previous change of government in 2010. Our ammonia chillers had been used for office buildings, laboratories, data centers, conference centers and even parliament chambers around the country, but principally right in the heart of London with several of them within a few hundred feet of the Houses of Parliament. These chillers have been in place and in operation for over 20 years with no issues related to toxicity or flammability, and have demonstrated significantly more efficient operation than the plant that they replaced, typically R-11 centrifugal chillers that ought to have been at least as good in energy terms. In one case, for an office building, the operator confirmed that his energy costs were halved after the retrofit.

Encouraged by this success, we set about to design a standard chiller for this building services application because every project up to that point had been a bespoke design to suit the project requirements. Almost as soon as we had completed the standardization exercise the government changed, the environmental policy that had supported those projects was discarded and the shutters came down.

All was not lost as we have found a ready market for the standard chillers in chill distribution warehouses, pharmaceutical plants, food production factories and ice rinks—most recently for a town in New York State that replaced an old R-22 chiller with an ammonia unit sitting alongside the old machinery room. Ironically, despite the undoubted success of the development project, we have not sold a single unit to government HVAC projects since 2010, but perhaps while the new brooms are sweeping clean, they might rediscover their environmental credentials and we can make a fresh start.