Ammonia As a Refrigerant: Pros and Cons
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As fewer and fewer CFCs and HCFCs are available for use as refrigerants, look for ammonia to become more popular as a 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.
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
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don
What is the percentage of refrigeration plants and refrigerated warehouses that are using ammonia refrigerant?
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.
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?
Tim
Sounds like an interesting discussion thread. Sounds very similar to some co-generation concepts being used. Anybody want to add comments? Thoughts?
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?
Tim
This might be a start? http://www.osha.gov/SLTC/etools/ammonia_refrigeration/receiving/storage.html
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[...] 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“). [...]
Dave
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.
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.
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.
Propane frig. question
[...] 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 [...]
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.
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.