Fridge not working

[Joe Romas]

Greg.

The difference is easy to spot!

Refrigerant is made and patented by Dupont. Every time a patent runs out it's suddenly dangerous and requires a new refrigerant and patent. LOL

Reading here it seems ammonia and water was the first refrigerant.
Refrigeration - Wikipedia, the free encyclopedia

Joe

[David Tilston]

Originally Posted by Casita Greg

Robert, Thanks for the info, but I already know the components of the system and how it works, but just to clarify a point you made above, ammonia refrigeration systems are used all over the world and on a huge scale in almost every aspect of cooling and freezing throughout many industries. I'm not sure that I'm following where you're coming from when you say that it isn't a refrigerant or a coolant. It has been since about 1900. I'm not trying to be argumentative, just trying to understand what the difference is between a bonafide "refrigerant," like Freon for example, and another chemical that is being used for the same function. I may be wrong, but in my mind, if it is used as a refrigerant, then it is a refrigerant. (You know the one about if it walks like a duck, quacks like a duck, etc.)

After re-reading the OP, I see that it functions on electric, but not on propane. Sounds like he needs to have the burner serviced.

Ammonia, propane, freon..... these are all used in compressor style refrigerators. They all depend on phase change to pump heat.

Our absorption style fridges do the same thing, but use partial pressures to make the ammonia think it has dropped in pressure and then evaporate, an endothermic process.

What I am curious about is where the crystals, referred to earlier, come from? Are they a chemical reaction with the ammonia and hydrogen, or steel, or water, or all four?

[Carol H]

Originally Posted by David Tilston

What I am curious about is where the crystals, referred to earlier, come from? Are they a chemical reaction with the ammonia and hydrogen, or steel, or water, or all four?

The properties of ammonia are such that it can crystalize if allowed to over heat. Which is what happens if the fridge is not level and unable to move the liquids and particles using only gravity as our fridges work. There may also be a chemical reaction with Hydrogen as well that will also cause some crystallizing.

As the cooling liquid solutions in our fridges depends on gravity to move the cooling liquids through it - if the fridge is run off level & as the crystals develop and accumulate in one spot they will cause the system to totally clog up and not work.

[rbryan]

Originally Posted by Casita Greg

Robert, Thanks for the info, but I already know the components of the system and how it works, but just to clarify a point you made above, ammonia refrigeration systems are used all over the world and on a huge scale in almost every aspect of cooling and freezing throughout many industries. I'm not sure that I'm following where you're coming from when you say that it isn't a refrigerant or a coolant. It has been since about 1900. I'm not trying to be argumentative, just trying to understand what the difference is between a bonafide "refrigerant," like Freon for example, and another chemical that is being used for the same function. I may be wrong, but in my mind, if it is used as a refrigerant, then it is a refrigerant. (You know the one about if it walks like a duck, quacks like a duck, etc.)

After re-reading the OP, I see that it functions on electric, but not on propane. Sounds like he needs to have the burner serviced.

We don't disagree Greg. If it acts as a coolant then it is one. I guess the difference is that a 'refrigerant' cools because of it's physical properties, rather than having some outside heat source change them. I also agree that the burner unit is the likely culprit.

[steve dunham]

I have worked on industrial cooling systems that used Freon ,ammonia and propane to cool product . None of these systems used heat to produce cooling,
all of the systems employed a compressor .Ammonia is often used in cooling systems to make the ice for indoor skating rinks and in large chemical and food processing plants where large amounts of refrigerant is required. If you have ever been around an ammonia compressor when it vents due to over pressure ,you would long remember the experience .

[David Tilston]

Yeah, heat to cool. That is kinda counter intuitive.

The heat is really just distilling the ammonia out of the water. The first big heat sink after the heater helps to condense any moisture out. It is sloped back toward the source to drain the water.

That Einstein guy was quite a genius:
http://www.fiberglassrv.com/forums/f...tml#post519993

[mmeyer]

Look up steam driven chillers, preferably with two effects , definitely use heat to cool. Granted there are heat exchangers and cooling towers involved.


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[rbryan]

Originally Posted by steve dunham

I have worked on industrial cooling systems that used Freon ,ammonia and propane to cool product . None of these systems used heat to produce cooling, all of the systems employed a compressor .

I appreciate your experience, but RV absorption refrigerators don't use a compressor. There's a condenser, an evaporator, an absorber and a generator (the boiler). So, the heat provides the energy to start the cycle.




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[steve dunham]

Originally Posted by rbryan

I appreciate your experience, but RV absorption refrigerators don't use a compressor. There's a condenser, an evaporator, an absorber and a generator (the boiler). So, the heat provides the energy to start the cycle.

Attachment 84602


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I am fully aware that the refrigerators in our trailers are an absorption type and do not have a compressor. My point was that ammonia is also used in compressor systems as a refrigerant. Freon is not the only thing that is used as a refrigerant .
I worked on old residential cooling systems that also used propane as a refrigerant . The propane systems employed a compressor not a heat source
The propane systems were replaced with Freon because of code changes and the hazards propane presented. I have also worked on cooling systems that were single pass well water systems .One system was pumping 600,000 gallons of groundwater / hour through the cooling system and then directly down the sewer.
The absorption refrigerators in our trailers are not energy efficient, require more maintenance and do not cool as well as a compressor refrigerator but they work for our application.

[rbryan]

Originally Posted by steve dunham

I am fully aware that the refrigerators in our trailers are an absorption type and do not have a compressor. My point was that ammonia is also used in compressor systems as a refrigerant. Freon is not the only thing that is used as a refrigerant .
I worked on old residential cooling systems that also used propane as a refrigerant . The propane systems employed a compressor not a heat source
The propane systems were replaced with Freon because of code changes and the hazards propane presented. I have also worked on cooling systems that were single pass well water systems .One system was pumping 600,000 gallons of groundwater / hour through the cooling system and then directly down the sewer.
The absorption refrigerators in our trailers are not energy efficient, require more maintenance and do not cool as well as a compressor refrigerator but they work for our application.

Thanks. I knew I had to be misreading your comments. You're right about these fridges too. Over at the Escape Forum there are a ton of members who have had fridge issues - especially when the ambient temperatures are warm. Some have gone to great lengths, adding several solar panels for example, and replacing the absorption fridge with a compressor based model.

[KenjiFox]

NH3 or ammonia is in-fact a refrigerant. It is designated as R717.
It is widely considered as one of, if not THE most efficient refrigerant.

There are no refrigerators that use "coolant", only refrigerant.
The only exception to that would be some kind of liquid chiller system using a remote condensing system to cool perhaps a glycol solution that is then used to cool a cabinet.
Even then, the phase exchange system responsible for the actual heat pumping has refrigerant in it.