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Old 15-05-2008, 02:51   #1
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alternative refrigerants?

Does anybody know much alternative refrigerants? I know jheldatksuedu seems to have experience with propane, but I am also wondering about ammonia and salt-based systems. I don’t see these replacing a danfoss, but you never really know and I find this sort of stuff interesting.

Let me kick this off with American Society Of Heating, Refrigerating And Air-Conditioning Engineers (ASHRAE) position paper on ammonia. They, the EPA and United Nations Environmental Programme like it.
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Old 15-05-2008, 11:32   #2
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Maren, there's plenty of information available on the web about them. Ammonia is an old answer (read "The Mosquito Coast", the book they made a movie from) and still very popular in commercial installations. But IIRC that's anhydrous ammonia and extremely dangerous is it leaks out, not something you'd want to live with.

There are similar problems--or performance problems--with all the miracle alternatives. And propane and other explosive gasses are generally frowned on for just that reason--explosive ability. Again, leaks are problematic and the one thing you can be sure of is that EVERY refrigeration system will leak, sooner or later. Or need to be disposed of, and the haulers don't want to hear "BOOM!" when they crunch some piece of machinery.

The EPA and the UN like many things. There are reasons why no manufacturer is racing to adopt them.
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Old 15-05-2008, 14:05   #3
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Maren, there's plenty of information available on the web about them. Ammonia is an old answer (read "The Mosquito Coast", the book they made a movie from) and still very popular in commercial installations. But IIRC that's anhydrous ammonia and extremely dangerous is it leaks out, not something you'd want to live with.

Yup... he's right on this one. Ammonia is also used in Norcold refrigerators. It's how they are able to run off 12VDC, Propane and 120/240VAC. They essentially heat the refrigerant to push it through the nozzles and evaporator. You suuuuure wouldn't want one to leak out though. Deadly stuff.
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Old 15-05-2008, 15:40   #4
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I spent quite a few years working in the food processing industry - including as engineering manager in a big (big - over 1000 employees) meat processing works - where ammonia is the usual refrigerant.

While safety has improved with the advent of centrifugal compressors, etc ammonia, while fine in a controlled industrial environment, is not the sort of thing I would want in a boat (especially), or other domestic situation unless in a very small unit. I would not like the volume of refrigerant in our boat freezer unit's receiver to get loose if it were ammonia - and we have had the situation where all its refrigerant has dropped out into the boat (we use SP34e on the boat which is a safe non CFC or HCFC drop in replacement for R12, R134, etc - we used R134a previously).

I have experienced an industrial leak of ammonia used as a refrigerant and that resulted in the evacuation of the whole plant and surrounding area even though the volume released was not large in comparison to the total volume on the site - the area could only be approached with breathing apparatus. I have also known plant engineers with permanent lung/sinus passage damage resulting from ammonia leaks.

Ammonia is cheap, so one of the attractions of its industrial use where volumes are large, but I suspect that given the very small quantities of refrigerant in most boat and domestic situations the cost difference per charge is neither here nor there especially in the recharge situation where the major costs are those of evacuation and drying.

So my roundup is that ammonia would be fine in very small toy refrigeration units for small refrigerators (and in the controlled industrial environment), but for the volumes of refrigerant needed for even a moderate sized freezer unit on a boat I would not have it. I am actually at a loss as to why anyone would want to use it in any domestic installations at all given the availability of safe modern refrigerants .
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Old 15-05-2008, 15:46   #5
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I worked at a place with a large commercial ammonia system, and was lucky enough to be around when a pressure relief valve vented. 30' away and it was like getting a face full of mace. Another added problem is the crackheads, they use the anhydrous ammonia to make meth, so can't purchase it legally, and will go to crazy lengths to steal the stuff if they find out you're storing it.
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Old 15-05-2008, 17:09   #6
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SP34e, despite SolPower's gushing claims, is just a mixture of 98% R-134a plus
"2% Propane / Ethanole" according to their papers. I'm not sure what the 2% of propane and ethanol buys besides exclusivity, but I was taught that any mixed gas replacement is problematic, in that if there is any leak, the gasses tend to leak at different rates resulting in the mixture coming apart and the requirement to COMPLETELY evacuate and refill the system. No topping up possible, because then you'd have no idea what the real mixture was.

In this case...maybe not so bad, since the worst that would happen is that the magic elixir would degenerate down to plain R-134a. Oh, wait a minute! [g] Yeah, how's that working for you, Midland? Has that two percent down anything really really noticeably different?
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Old 15-05-2008, 17:15   #7
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Originally Posted by MidLandOne View Post
I spent quite a few years working in the food processing industry - including as engineering manager in a big (big - over 1000 employees) meat processing works - where ammonia is the usual refrigerant.

While safety has improved with the advent of centrifugal compressors, etc ammonia, while fine in a controlled industrial environment, is not the sort of thing I would want in a boat (especially), or other domestic situation unless in a very small unit. I would not like the volume of refrigerant in our boat freezer unit's receiver to get loose if it were ammonia - and we have had the situation where all its refrigerant has dropped out into the boat (we use SP34e on the boat which is a safe non CFC or HCFC drop in replacement for R12, R134, etc - we used R134a previously).

I have experienced an industrial leak of ammonia used as a refrigerant and that resulted in the evacuation of the whole plant and surrounding area even though the volume released was not large in comparison to the total volume on the site - the area could only be approached with breathing apparatus. I have also known plant engineers with permanent lung/sinus passage damage resulting from ammonia leaks.

Ammonia is cheap, so one of the attractions of its industrial use where volumes are large, but I suspect that given the very small quantities of refrigerant in most boat and domestic situations the cost difference per charge is neither here nor there especially in the recharge situation where the major costs are those of evacuation and drying.

So my roundup is that ammonia would be fine in very small toy refrigeration units for small refrigerators (and in the controlled industrial environment), but for the volumes of refrigerant needed for even a moderate sized freezer unit on a boat I would not have it. I am actually at a loss as to why anyone would want to use it in any domestic installations at all given the availability of safe modern refrigerants .
Good information. I think they use ammonia in refrigerators in RVs and boats in order to allow them to run off propane. I'm not sure any other refrigerant is capable of being heated to do its cooling work with the same efficiency... well, at least that's what I assume.
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Old 15-05-2008, 17:22   #8
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Sean, "flame" refrigerators normally have to be kept level and for that reason they are not generally intended for marine use.

Even if your new cat occassionally isn't porpoising into the clouds.<G>
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Old 15-05-2008, 18:10   #9
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Sean, "flame" refrigerators normally have to be kept level and for that reason they are not generally intended for marine use.

Even if your new cat occassionally isn't porpoising into the clouds.<G>
Ha ha ha.

When I was researching refrigeration units for the RV, I found some LPG/Propane units that are engineered specifically for boats. They had a large angle of operation compatible with boats. I wish I could find the link right now, but... here is one from NZ sold for boats:

43ltr Upright 3 Way Gas Fridge by Koolzone - Smart Marine

Also, my boat came from the factory with a gas absorbtion refer in it. The gas lines are still in place and labeled.

Just saying they are out there... is all.
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Old 16-05-2008, 04:05   #10
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MidLandOne (et al),
Thanks for the taking the time to reply. I've responded to yours because you post implies you have the most actual experience with ammonia and I have other questions. But if you don’t mind I’ll reorder part of the post to clarify something for everyone.

Quote:
I am actually at a loss as to why anyone would want to use it in any domestic installations at all given the availability of safe modern refrigerants.
Sometimes I think I should start putting part of my posts in bold, so let me do that that now since the central theme appears to have been read incorrectly.

Quote:
Does anybody know much alternative refrigerants? I know jheldatksuedu seems to have experience with propane, but I am also wondering about ammonia and salt-based systems. I don’t see these replacing a danfoss, but you never really know and I find this sort of stuff interesting.
Ok, with that said, here is what I see as the key points you mentioned.
  • Cost savings come in industrial quantities but since leaks require the full evacuation of the system this is not cost effective in smaller amounts.
  • The irritant effect is manageable in small amounts but is too large in volumes the size of a normal fridge or freezer
What I found most interesting was the part about advent of centrifugal compressors. Do you know anything more about them? Also, I know Ammonia is a corrosive. Do you know anything about how that is dealt with?

As for the stated concerns on the concentration of ammonia,

Quote:
The National Institute for Occupational Safety and Health (NIOSH), in its 1997 Pocket Guide1, has set the immediately dangerous to life and health (IDLH) level, the level at which an individual could be exposed for 30 minutes without a respirator and not experience any lasting health effects, at 500 parts per million. Ammonia’s sharp, irritating, pungent odor actually helps reduce exposure to potentially dangerous concentrations. The average odor threshold is 5 ppm2, well below concentrations that may cause harmful effects to the human anatomy.
What they don’t address directly is in one case they are talking about ammonia but in another they are talking about anhydrous ammonia.


Hellosailor:

1. I read the Mosquito Coast about 20 years ago (man, that long?!?). The quote I remember well is: "He's the worst kind of pain in the neck -- a know-it-all who is sometimes right". Just to be clear, I’m not trying to imply anything here. It was just a quote I've thought noteworthy over the years.

2. You mention IIRC -- what's that?

3. The EPA and the UN like many things. There are reasons why no manufacturer is racing to adopt them.

I’m not really sure how to respond to this one. I understand you might have something against the EPA or UN, but you really didn’t address the content – just the source. As for the engineering society, whose members presumably work for the manufactures, you just ignored.
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Old 16-05-2008, 04:19   #11
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Ammonia is considered a high health hazard because it is corrosive (caustic) to the skin, eyes, and lungs.
Exposure to 300 ppm is immediately dangerous to life and health.
Ammonia is also flammable at concentrations of approximately 15% to 28% by volume in air. When mixed with lubricating oils, its flammable concentration range is increased. It can explode if released in an enclosed space with a source of ignition present, or if a vessel containing anhydrous ammonia is exposed to fire.
Fortunately, ammonia has a low odor threshold (20 ppm), so most people will seek relief at much lower concentrations.

A report describing galvanic corrosion found in an ammonia refrigeration pipe used near brine tanks:
Report of Examination of Samples

Anhydrous Ammonia (Nh3) means ammonia without water, as opposed to Aqueous Ammonia (Ammonium Hydroxide, Nh4OH).
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Old 16-05-2008, 06:03   #12
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Originally Posted by hellosailor View Post
SP34e, despite SolPower's gushing claims, is just a mixture of 98% R-134a plus
"2% Propane / Ethanole" according to their papers. I'm not sure what the 2% of propane and ethanol buys besides exclusivity, but I was taught that any mixed gas replacement is problematic, in that if there is any leak, the gasses tend to leak at different rates resulting in the mixture coming apart and the requirement to COMPLETELY evacuate and refill the system. No topping up possible, because then you'd have no idea what the real mixture was.

In this case...maybe not so bad, since the worst that would happen is that the magic elixir would degenerate down to plain R-134a. Oh, wait a minute! [g] Yeah, how's that working for you, Midland? Has that two percent down anything really really noticeably different?
Yes that is correct but I think you will find that I made no claim otherwise and all I stated for the sake of information was that we used R-134a before and now use SP34e which is a drop in replacement for that. As far as I know R-134a is still an accepted safe refrigerant itself so I am unsure what the worry is if the other factions (ethanol and propane) in SP34e do disappear.

Solpower make no secret of the components (they are stated in the safety information data sheet) and unless there has been some recent change it is accepted most places I know as a drop in replacement for unsafe CFC12 or as original charge (in the case of the USA it is, again unless there has been a recent change, on the EPA's register as acceptable for various drop in and original charge over a range of refrigeration services).

Solpower claim that SP34e is suitable for mineral oil lubrication whereas synthetic is, supposedly,required for R-134a. Regarding leakage of factions I could not comment except that if the claim that R-134a requires synthetic lube is correct then one assumes it is something about the propane and ethonal (the components of SP34e other than 1,1,1,2-tetrafluoroethane - aka R-134a) that allows this and stabilises the refrigerant so that it does not revert back to R-134a which would be unhappy with mineral oil.

In the end, if SP34e reverts to R-134a, assuming there is not a lube issue I don't know what the problem is?
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Old 16-05-2008, 06:20   #13
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What I found most interesting was the part about advent of centrifugal compressors. Do you know anything more about them? Also, I know Ammonia is a corrosive. Do you know anything about how that is dealt with?
Centrifugal and rotary screw compressors have been around for industrial refrigeration (and also large AirCon) since at least the 1970's that I know of (probably earlier, but I am not that old ) replacing recipricating compressors. If you google to Howden Compressor Company and York Process Systems you should find something about them.

The first line of attack dealing with ammonia exposure of external parts of the body is flushing with water. How internals are treated eg the lungs, I do not know but I assume the primary treatment is removal of the body's secreted fluid in order to prevent drowning.
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Old 19-05-2008, 23:19   #14
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Has anyone heard of Tropikool? They are in the LA area and they use a refrigerator system that uses CO2. to charge the system you would use the CO2 bombs that are used for inflatable PFDs. I have two units mounted on Windseeker II in our Freezer and Refer and they work GREAT! Draw about 8 Amps in 24 hours. Their Web site is
www.tropikool.com JL
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Old 20-05-2008, 00:39   #15
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Has anyone heard of Tropikool? They are in the LA area and they use a refrigerator system that uses CO2. to charge the system you would use the CO2 bombs that are used for inflatable PFDs. I have two units mounted on Windseeker II in our Freezer and Refer and they work GREAT! Draw about 8 Amps in 24 hours. Their Web site is
www.tropikool.com JL

No and I couldn't get the link up. But I found this link, s/v Horizion, and they installed one.

One thing I noticed as a commentary was that they had some problems with the setup and system is extremely sensitive to the set up. But once they got all the kinks ironed out, they were really happy with it.

I'll try that link a bit later. Thanks
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