ACHRNEWS

Ammonia's advantages

July 27, 2000
For today and in the future, low-temperature refrigeration is indispensable. With the exception of a few special fields, a circulating refrigerant is required.

CFCs, which had been used for this purpose, have become discredited, and their production halted, due to the depletion of the ozone layer. Of course, they are prohibited for use in new systems.

Since the invention of the refrigerating machine in the past century, large refrigerating systems in the food, beverage, and chemical industries have predominantly been built for ammonia refrigerant. Today, this is still the case.

It is a fact that ammonia in comparison to other substances can serve its purpose with by far the least consumption of energy. Nearly all over Europe, in almost all dairies, breweries, slaughterhouses, and large freezing plants, ammonia has been used for many decades.

It is surprising that competing substances could ever challenge ammonia’s position as a refrigerant.

Yet, some challenges were offered, including the propagation of so-called “safer refrigerants.” In fact, some ammonia producers also produce other refrigerants, which can be marketed much more profitably.

The benefits of ammonia

The technological advantage of ammonia is that it requires only small-dimensioned piping and throttle cross sections.

At the same time, assembling copper piping is part of the daily routine of technicians. But due to ammonia’s incompatibility with copper, different technologies have to be used for building ammonia systems — a job which so far can only be mastered by a few specialized companies.

In general, ammonia is a natural refrigerant with only minor risk potential. Some points:

  • In nature, ammonia is produced by biological processes, is naturally decomposed, and does not add to the global greenhouse effect.

  • Only 3% of the ammonia existing on this planet results from human activity, even though it is produced in large quantities for fertilizers.

  • Ammonia is readily soluble in water; the solution is called sal ammoniac, which is well-known in households.

  • The odor of ammonia has a highly alerting effect. Even the slightest traces of ammonia in the air can be perceived easily. Refrigerant leaks are therefore detected at once.


As long as a person can voluntarily endure the smell, only completely harmless concentrations exist. Actually, even among persons who are used to relatively high concentrations of ammonia due to their work, not a single case of a lasting disease has been reported over an observation period of several generations.

Of course, there is no reason for thoughtless handling of ammonia, and in any case, there are reasons for legitimate reservations where the effects on a crowd are concerned if suddenly exposed to the smell of ammonia. Increased attention is also required for preventing liquid ammonia from getting into sewage or ground water.

  • Ammonia refrigeration systems do not require explosion prevention. In a compound with air, ammonia is ignitable only within a very narrow span of concentrations — and this only in combination with high-ignition energy. Therefore, fears of explosions are unfounded; not even from war-zones have any NH3-relevant incidents have been reported.

    In this respect, ammonia differs substantially from the other natural refrigerants currently under discussion, such as propane and butane.

  • Ammonia accidents have no serious consequences for the neighboring community. Unforeseeable emissions cannot be completely ruled out. However, except for a temporary irritation by bad smell for the neighboring residents, no further consequences need to be feared.

    Gaseous ammonia is considerably lighter than air. Therefore, it ascends quickly to higher atmospheric layers. There, it decomposes within a few days. The released nitrogen is washed out by rain and spread out as a fertilizer in the ground of the farther surroundings.

  • Ammonia protects the Earth’s atmosphere. By using ammonia, refrigeration can be realized with the least possible energy requirement. In this respect, the endeavors to reduce the global greenhouse effect can also be best supported with this refrigerant.

    In comparison to existing old systems, modern ammonia systems are designed for clearly reduced refrigerant charges. They correspond to ideas that do justice to today’s environmental awareness.

The fears of ammonia’s risks, which are for a large part unnecessary, must not lead to exaggerated requirements by supervisory authorities.

EDITOR’ S NOTE: This material was translated from the original German and was prepared by Eurammon of Frankfurt, Germany, for distribution at a past IKK trade show.

Sidebar: A question of long-term use

It should be no surprise to News subscribers that R-134a, one of the “ozone friendly” replacements for CFC refrigerants, is under scrutiny due to its global warming potential (GWP). This scrutiny seems especially strong in Europe, where CFCs originally came under heavy criticism before the Clean Air Act banned venting and gradually halted production in the United States.

The two following articles offer two differing viewpoints on refrigerants that have been put under something of a political microscope: ammonia (NH3) and R-134a. Ammonia use is heavily regulated in North America, which adds to its expense, and 134a’s GWP is causing some in Europe to opt for its eventual discontinuance.