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  • ammonia for refridgerant.

    anybody know anything about recharging RV refrig that uses ammonia for refridgerant?, uses gas for energy source.
    "four to tow, two to go"

  • #2
    I don't know about recharging them, but I find them interesting. One thing I discovered is that they don't begin to cool right away. They have to run awhile before the cooling cycle begins. Then they can continue to cool for some time after the heating part of the cycle stops.

    Recharging- is it likely that if it needs a recharge that it has some 'issues' that need to be addressed- like pinholes maybe? I'm not sure, but I seem to recall that they work on a little higher pressure than a freon type would. You'd want to be sure of the structural integrity of the system before refilling it. I've seen a few of these type coolers in motorhomes and campers, and some of them look downright scary what with rust, etc.
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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    • #3
      On the other hand, despite recalls and scare campaigns against them, they are the ONLY type that has the very REAL potential to work directly off solar energy. Heat is heat.

      The same sun that heats up the house could cool it...... I understand that this is already done by the Club Med resorts on Martinique, but I have never seen details of the system.
      1601 2137 5683 1002 1437

      Keep eye on ball.
      Hashim Khan

      If you look closely at a digital signal, you find out it is really analog......

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      • #4
        About 2 yrs ago had to throw a way a late 40's Kelvinator refrig, because the ammonia started to seep out of the coil, couldn't find anyone to fix it, as it was in a house, the tech said RV's (vented outside) and commerical refrigeration are the only ones currently using ammonia. There was a blurb on the news a while back, some Hyundias and Kias were shipped to the US with butane mix (used in Asia) in the AC units, instead of r134a.
        jack

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        • #5
          Ammonia cooling

          Ammonia-based cooling was used in rural cooling sheds (some very large) in Australia for storing fruit for use and better "prices" in the "off season". They were usually sited with Packing Sheds as well.

          We had them everywhere there were orchards with perishable fruit. This was well before modern chillers/coolers. The big problem was the cloud of ammonia if it leaked. But they gave good service in their day.

          There are few if any left at all let alone operational I would think.

          I don't know if the process would be viable - or perhaps allowed - today.

          One of the several Refrig/Heating/Cooling professionals on this forum will be much better able to advise on this than I can.

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          • #6
            A buddy of mine had this fridge in his motorhome, it started to leak ( I could smell the ammonia), the local RV place told him it was againist state law (Oklahoma) to repair these units, he bought a new one ($1010.00), he gave me the old one, I am gonna attempt to locate the leak and repair it. I have charged many air conditioners but have never worked on one of these, I want to do this for educational purposes.
            "four to tow, two to go"

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            • #7
              Ammonia units in RV's can kill you.A friend had one in his camper,they were off on a trip,the first night they ran the unit they smelled something funny,but paid no attention to it.Later he was outside the RV at the camp ground when he heard jis wife scream and come busting out the door onto the ground.The smell turns out had been ammonia leaking and once the unit had run awhile it built up enough pressure where the leak(in a soldered coil bend)let loose and emptied the contents into the living space.

              She survived but barely.She had chemical burns on her arms and face from the ammonia and the ammonia she inhaled before escaping scared her lungs.If she had been asleep it could have been much worse.

              If it were me I would run a pressure test on the system before I attempted any fix.Just a thought.
              I just need one more tool,just one!

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              • #8
                Originally posted by speedsport
                anybody know anything about recharging RV refrig that uses ammonia
                I know little about recharging, except that it's an extreme hazard. Ammonia gas is highly toxic (lethal @ 0.5% ). It is also a problem on skin, and eyes.

                Before you start cutting without breathing, find a place to buy Ammonia Gas. Airgas has 4# lecture bottles, and you will need a CGA 180 regulator, and probably a way to pinch off the fill line.

                There WAS a company that provided rebuilt assemblies, saw it a few years ago. Send them your old frig plumbing, and get a fixed one back. Google may find it.

                But, the real problem, (I've been told), is that these frig's don't usually fail from leaks. They fail because of crap that builds up in the orifices. If you can't get the crap out, it doesn't work, no matter if there is proper Ammonia.

                Have you taken it out and left it upside down for a day? Supposedly this works (sometimes).

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                • #9
                  Ammonia is still widely used in large cold storage and food processing facilities. It is not compatible with copper pipe so steel pipe and valves are used. In this application ammonia is the refrigerant and the vapor compression cycle is much the same as freon refrigerants. RV refrigerators work on a different cycle, the absorbtion refrigeration cycle. In this cycle a mixture of ammonia and water are charged into the refrigerator. Ammonia is the absorbent and water is the refrigerant. Pressures can be very high. When a unit leaks it is best not to repair it. A gas company (ARKLA?)built natural gas fired absorbtion residential chillers years ago. As in the refrigerators no compressor is used just a heat source. Many industries that have a waste heat source utilize lithium bromide/water absorbtion chillers. Sizes begin about 500 tons cooling. They can be gas fired or more commonly steam is the heat source.

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                  • #10
                    What deltap said is right on.
                    We had a major Ammonia leak at a Plant I worked at.
                    The fire department put on the Fog-Spray and went in.
                    Ammonia has a temendous affinity to water, and the vapors IMMEDIATELY
                    get absorbed, and run down the drain. When a leak occurs, the water in your eyes absorb this and that is why they burn, in fact, the
                    water in your skin is also exposed the same way, and the injuries are really burns . Smelling salts are not even comparable to a Liquid Ammonia leak..very dangerous..
                    Rich
                    Green Bay, WI

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                    • #11
                      Magic!

                      Originally posted by deltap
                      Ammonia is still widely used in large cold storage and food processing facilities. It is not compatible with copper pipe so steel pipe and valves are used. In this application ammonia is the refrigerant and the vapor compression cycle is much the same as freon refrigerants. RV refrigerators work on a different cycle, the absorbtion refrigeration cycle. In this cycle a mixture of ammonia and water are charged into the refrigerator. Ammonia is the absorbent and water is the refrigerant. Pressures can be very high. When a unit leaks it is best not to repair it. A gas company (ARKLA?)built natural gas fired absorbtion residential chillers years ago. As in the refrigerators no compressor is used just a heat source. Many industries that have a waste heat source utilize lithium bromide/water absorbtion chillers. Sizes begin about 500 tons cooling. They can be gas fired or more commonly steam is the heat source.

                      I've read numerous explanations, in various degrees of detail, of how the adsorption refrigeration cycle works. All of them seem to involve a fair degree of hand-waving, but that's probably due to my limited background in chemistry and physics. In any case, the process certainly appears to work.

                      BUT, any gizmo that gets cold when you build a fire under it seems to be dangerously close to witchcraft!

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                      • #12
                        About 25 years ago I was working on a ship in Portland, OR installing a new radio direction finder. My helper and I stayed overnight on the ship as we had worked late into the night. It was an ammonia tanker.

                        That night after we'd turned in they had a burst tank or pipe - don't recall which, but the crew and entire city sector were evacuated. The crew forgot we were in guest quarters and when they abandoned ship we were left behind and slept through it all. The next morning we walked around the now ghost ship looking for people, then went out on the starboard bridge wing and saw the moonsuits working. They like to crapped their pants when they saw us walk out and wave. They had only just capped the leak and the ammonia had barely dispersed. Nobody knows why we weren't dead. Favorable wind off the Williamette River, I suppose, and that the port to the quarters was closed.

                        That's some bad stuff. I used to do refrigeration (air conditioning on yachts) work and I wouldn't touch it. Is that a Servel refrigeration process? I used to rent a house that had a Servel refrigerator and it worked great right up to the day it quit and then it went to the dump

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                        • #13
                          I was chief engineer in a dairy. Ice cream production at about 25,000 gal. per day. Ammonia was the refrigerant used. 300 ton compression system. As was mentioned, the little RV units are absorbtion systems. I would definately NOT try a repair. The exact ammount of ammonia, water and possibly inert gas must be measured into the system. If it rusted thru in a pin hole there are many more just waiting to blossom.
                          I don't believe ammonia is toxic. It is highly irritating and will " burn " the mucus membrains along with the skin if the consentration is high. It must be handled with great respect. KNOW what you are about before you start.
                          Jim

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                          • #14
                            RV Refrigerators

                            RV's use the old Servel system. For basic explanation get out your old Thermodynamics text. This system is an adsorption system not a compressor system. Normally trouble free but heavy weight. Our Fridg went out recently. A rebuilt unit with labor was within $200 of the cost of a new unit. The new unit has several new features like a door lock that the old one did not. Better shelf arrangement and in door space. Ours would not come through the entry door. They had to remove the drivers seat and come in that way. New is the way to go.
                            Byron Boucher
                            Burnet, TX

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                            • #15
                              If anyone is interested, I have a RV refrigerator free (if you pick it up) to good home. The ammmonia absorbtion type, runs on propane or electric - but the propane thermostat is broken. The unit is small - stands about 3.5 to 4' tall. Came out of an Airstream trailer.
                              Weston Bye - Author, The Mechatronist column, Digital Machinist magazine
                              ~Practitioner of the Electromechanical Arts~

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