Ammonia As a Refrigerant: Pros and Cons

Ammonia as a RefrigerantLast month, a 5000 pound ammonia leak occurred at a Boston-area seafood warehouse that killed one worker and forced a shelter-in-place order from Boston Police.  Problematic procedures may be to blame. So as you read the pros and cons of Ammonia as a refrigerant below, remember these key takeaways: ongoing, scheduled evaluations and preemptive maintenance are critical for any ammonia storage solution — lax procedures place workers and residents in danger.

Why is Ammonia growing in popularity given this risk? As fewer and fewer CFCs and HCFCs are available for use as refrigerants, companies are looking to ammonia as a more effective replacement. According to ASHRAE and the International Institute of Ammonia Refrigeration (IIAR), ammonia is a cost-effective, efficient alternative to CFCs and HCFCs that is also safe for the environment.

Check out this related content:

Ammonia (chemical formula NH3) is a gas comprised of two other gases — nitrogen and hydrogen. Whether found in nature or made by man, ammonia is colorless but has a sharp, pungent odor. Ammonia, frequently used commercially in large freezing and refrigeration plants is also called “anhydrous ammonia” because it contains almost no water (it is 99.98% pure). Household ammonia, by comparison, is only about 10% ammonia by weight mixed with water.

As a refrigerant, ammonia has four major advantages over CFCs and HCFCs:

  • An ammonia-based refrigeration systems costs 10-20% less to build than one that uses CFCs because narrower-diameter piping can be used.
  • Ammonia is a 3-10% more efficient refrigerant than CFCs, so an ammonia-based system requires less electricity, resulting in lower operating costs.
  • Ammonia is safe for the environment, with an Ozone Depletion Potential (ODP) rating of 0 and a Global Warming Potential (GWP) rating of 0.
  • Ammonia is substantially less expensive than CFCs or HCFCs

There are two key disadvantages to using ammonia as a refrigerant:

  • It is not compatible with copper, so it cannot be used in any system with copper pipes.
  • Ammonia is poisonous in high concentrations. Two factors, however, mitigate this risk: ammonia’s distinctive smell is detectable at concentrations well below those considered to be dangerous, and ammonia is lighter than air, so if any does leak, it will rise and dissipate in the atmosphere.

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Matt Cardin
Goodway Blogging Team

32 comments


  • don

    What is the percentage of refrigeration plants and refrigerated warehouses that are using ammonia refrigerant?

    May 21, 2011
  • Tim

    In the research that I did, most large scale industrial refrigeration uses ammonia refrigerant. So 80%-90%. It’s use in commercial HVAC applications is also growing.

    May 23, 2011
  • Dipankar Ghosh

    How is the Oil& Gas Industry looking at ammonia as a replacement of CFCs and propane refrigeration? What about using waste heat (from GT power plants) to produce refrigeration using absorption refrigeration process using ammonia, which can be used for hydrocarbon condensate recovery and other chilling requirement for air conditioning etc. ?
    Can any body throw light on this?

    July 7, 2011
  • Tim

    Sounds like an interesting discussion thread. Sounds very similar to some co-generation concepts being used. Anybody want to add comments? Thoughts?

    July 25, 2011
  • Mike

    Hello, I’m new to the refrigerant recovery industry and I was hoping somebody could give me some insight on how to easily identify ammonia tanks from other refrigerant tanks?

    July 29, 2011
  • […] However, only qualified technicians should handle ammonia refrigerants, because working on an ammonia refrigeration system is different than working on other refrigeration systems, he says. For example, while copper tubing is commonly used in smaller HVAC systems, it should never be used in an ammonia refrigeration system. (Editors Note: Check out our popular post on this topic: “Ammonia As a Refrigerant: Pros and Cons“). […]

    March 19, 2012
  • This was a really great article. After weighing the pros and cons of ammonia, I have to say it seems like a good idea.

    It is all too often that people break into your AC unit to steal the copper anyway. I’d like to see newer units come out that have done away with the copper cooling coils and instead use ammonia and another metal for the coils.

    October 25, 2012
  • joe

    I get tired of seeing ammonia listed as “poisonous in high concentrations” as a disadvantage. ALL refrigerants are “poisonous in high concentrations”. This is because they ALL displace the oxygen you need to breathe.

    November 11, 2012
  • RAMBOY

    Joe,
    The problem lies in the chemistry of CFC’s vs Ammonia. CFC’s are a simple asphyxiant which means they displace the air we need to breathe Ammonia will attack the moisture in the mucous membranes (chemical asphyxiant) and cause much greater damage at the ppm level. CFC’s have to be at percentage level to be dangerous.

    March 26, 2013
  • […] that's used in refrigeration is a gas and not a liquid. http://www.goodway.com/hvac-blog/2009/08/ammonia-as-a-refrigerant-pros-and-cons/ "Ammonia (chemical formula NH3) is a gas comprised of two other gases — nitrogen and […]

    May 12, 2013
  • EnDeep

    This had to of been written by someone with financial gains from using Amonia in refrigeration systems. Talk to anyone who works in refrigeration and they’re terrified of working on Amonia systems because it kills you instantly, freon doesn’t kill you.

    May 13, 2013
  • Tim

    If it was, I’m still waiting for my check 😉 Thanks for the comment. When used properly, Ammonia offers terrific heat exchange properties, as do other refrigerants. This article is mainly to identify that there are pro’s and cons to using Ammonia. Overall there are a variety of refrigerants that can be used by varying systems and you should check with manufacturers as to what they recommend.

    May 17, 2013
  • Roger Norton

    The comments from EnDeep show how people are misinformed about ammonia refrigeration. Ammonia refrigeration is the safest option both environmentally and economically.

    January 1, 2014
  • Eddie

    If ammonia was compatible with aluminum metal, then there would be another “Pro” for using it; the cost of aluminum is a far cry cheaper then copper.

    February 25, 2014
  • Brenda

    I had to be taken to hospital yesterday after my Electrolux wine refrigerator leaked ammonia. I opened the door and inhaled a whole fridge full. Firemen with breathing apparatus had to be called and they insisted that I was to be taken to hospital. Believe you me, ammonia might be distinctive in smell but when you have a fridge full burning your face and throat you don’t want to have anything to do with a fridge that uses NH3

    February 28, 2014
  • Can ammonia be serve as an R12 refrigerant? if so, what are its properties and materials effect

    April 12, 2014
  • Ekemini James

    what are the effects of ammonia on an ammonia-based refrigeratoin system?

    April 22, 2014
  • Balla Abubakar

    Can someone help me out with a full report on ammonia as a substitute for refrigerants, including its properties and material effects?

    November 16, 2014
  • ganesh

    Hi this is ganesh. We are using ammonia chiller for -25 degree application. In recent past we are facing problem of sudden oil carryover from oil separator and getting into phe which affects heat transfer and chiller trips. Can anyone help in what could have been issue.

    November 1, 2015
  • Hi, Thank You for this bit of info. We are using Industrial refrigeration with ammonia as a refrigerant. Ammonia acts as a very good refrigerant.

    February 15, 2016
  • Now which is the best refrigerant to be used in the industry?

    March 24, 2016
  • John

    Looking forward to the change to ammonia refrigeration systems. They used ammonia refrigeration systems on the brine systems on the salmon tenders in Alaska. One time there was a large venting of ammonia off the stern of a boat, and I was pretty much trapped on the other side. Felt I had to get past that leak and did. Not pleasant but no trip to the hospital. If I had been older and wiser, I would have just walked around to the bow and exited that way. Age and wisdom is a good thing. Most, if not all, travel trailers use ammonia systems for refrigeration, without negative repercussions. Freons are extremely strong green house gasses, 1000’s of time stronger than CO2, and take 1000’s of years to break down in the atmosphere (the carbon cycle for CO2 is in the order of two decades or less). Ammonia has no green house potential and is a fertilizer for plant growth, especially when mixed with atmospheric water, for which it has a strong affinity.

    July 23, 2016
  • Kenny

    I’m curious as to how much the energy savings is over cfc’s and hcfc’s. Mainly, I’m curious if the compressors are easier to start with an ammonia system.

    August 2, 2016
  • Ammonia contains a substantially larger amount of BTUs per pound. Installs and facilities using it are regulated far heavier that conventional refrigerants. Its safe and VERY cost effective. I for one am a huge fan of it……and Ive been an ammonia mechanic for years. CFCs and HCFCs have their place, but larger installs ammonia’s the only way to go.

    October 28, 2016
  • great article as always. I always enjoy reading them

    November 2, 2016
  • tom murphy

    Years ago, before Chicago opted for chilled water cooling in downtown buildings i advised alderman Ed Smith of the dangers of ammonia systems in the middle of a large population of people. The use of this product has never been made safe to use. When an accident happens people die within a wide area. Look at the history.

    December 27, 2016
  • UMESH BAKAL

    can you elaborate a little why LiBr-Water is more often used in vapor absorption system. I mean what are the disadvantages of Ammonia-water pair compared to LiBr-Water

    January 6, 2017
  • John Cantwell

    Do ammonia refrigeration plants have safety systems such as automatically triggered water fog or spray systems to quickly dilute leaking anhydrous ammonia?
    Could such a system be adapted to smaller applications?

    March 17, 2017
  • Farrukh Shahzad

    sir i want ask can i use ammonia refrigeration system for cooling of plastic injection molding machines and mold.

    May 19, 2017
  • Mubassir

    As per my knowledge Ammonia is called “Self Alarming Gas” because of its pungent smell. if there is any leak in its system then you can smell the pungent odor of Ammonia and can safeguard your system

    May 21, 2017
  • swapnil kotrange

    what are the other alternative refrigerants to ammonia which should be eco friendly having low ODP and GWP value and economical too ?

    June 16, 2017

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