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The Ammonia problem... Answered

I am still trying to build a half decent absorption fridge/freezer for the hot summer days down here.
Usually anhydrous ammonia and water is used for these old style systems.
Problem is that destilling it at home is not the nicest thing, especially in the currently hot weather.
So I called up a few refrigeration guys to inquire on the price of some Ammonia if they fill the system for me instead.
No matter how I try these guys will only fill certified systems but nothing build in your backyard that is missing the required certifications.
Not even for a proof of concept to see if it is working and the gas removed when done with that.
Was also informed that making or just having highly concetrated or even anhydrous ammonia would require that I obtain a permit first :(
Big question:
What are the alternives for R707 or Ammonia in an old style "Icy Ball" system?
Small question: Has anyone done it and is willing to share some tips here?

Discussions

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iceng

2 years ago

Last year had a man refill my ammonia RV fridge..

He told me several other gasses must be mixed for it to work but not what names or amounts...

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Downunder35miceng

Answer 2 years ago

It is just hydrogen that is required for the RV systems.
Together with the ammonia and a bit of water it forms the continous cycle.
Just air won't work as you need a lighter gas that seperates easy from the heavier ammonia gas or the liquid form.
And since it is a "normal product" no problem getting it filled, but come with something that has no labels, make or brand name and is home made...
A normal sized RV fridge or freezer only uses about 60g of ammonia but something like an Icy ball would require quite a bit more.
For them all is based on internal volume and amount of water used.
Basically you boil out the ammonia and the resulting pressure turns it into a liquid that collects on the other side.
After that it evaporates and dissolves into the now cold water until heated again.
Instead of the water you can also use calcium chloride in a "dry" system.
Thing is right now I am a bit unsure on how to proceed with the project.
What sounded like a lot of fun and learning turns out to be a problem with the law instead.
Thank you all drug cooks for my life harder than it should be! ROFL

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icengDownunder35m

Answer 2 years ago

Why would your country legislate this kind of protectionism against new manufacturers ?

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steveastrouk

2 years ago

Distill my son's socks :-)

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Downunder35msteveastrouk

Answer 2 years ago

Good one, I like it but maybe washing the sneakers every once in a while and wearing cotton socks could help more? ;)

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steveastroukDownunder35m

Answer 2 years ago

Well YOU tell him, Mr Smarty Pants........

We don't go in his room, unless someone is outside, ready to pull the other out, if we fall unconscious.

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Jack A Lopez

2 years ago

I do not think it is just a matter of finding an alternative to the refrigerant, because you have to consider the sorbent too.

As an example, I think propane has similar vapor pressure (as function of temperature) to ammonia, but propane will not absorb into water. I mean propane and water are totally immiscible, like oil and water.

Whereas water and ammonia are just totally in love with one another, although not so much that a little heat can't drive them apart, which I guess is the basis for these sorption type refrigerators.

Actually that's an important point: it has to be just a little bit of heat required to liberate/regenerate the refirigerant. I mean there's water in cured concrete, but how much heat, at what temperature, would be required to drive it out?

The Wikipedia page for "Absorption refrigeration", mentions water and some inorganic salts, specifically lithium chloride and bromium chloride, as a refrigerant-sorbent pair.

https://en.wikipedia.org/wiki/Absorption_refrigera...

Probably somewhere on this Internet here, there is a list of well known refrigerant-sorbent pairs. Some examples: ammonia-water, ammonia-calcium chloride, water-zeolite, methanol-activated carbon.

Regarding methanol sorbed to activated carbon, I remember there was someone giving a TED(r) talk about a no-electricity refrigerator, based on that refrigerant-sorbent pair, for use in less developed parts of the world.

Although the awful thing about these TED(r) talks is, I don't think they ever evolve beyond much talk. I mean there seem to be all kinds of wonderful inventions, but they'll never be mass-produced, unless people start making them in their garages themselves.

Actually, I think it was the Wikipedia article on "Icyball" that linked me to that TED talk. Specifically:

https://en.wikipedia.org/wiki/Icyball

https://www.ted.com/talks/adam_grosser_and_his_sus...

Oh, final note, like last week, I noticed somebody on Youtube making anhydrous ammonia in his garage. It required a kind of exotic refrigerator, one that gets colder than boiling ammonia at ambient pressure. That plus some other laboratory-type glassware.

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Downunder35mJack A Lopez

Answer 2 years ago

Several absorption fridge models have actually made it into third world countries as parts of humananitarian help.
Mostly ammonia/chloride types using salvaged vaccum tubes from hot water systems and a round reflector for the sun.
Problem with these is that most are created on site with whatever materials are available, only the stuff known to be hard to find is supplied.
And of course we never really know what organisation does what in these parts of the world.
From talks with some old folks here I found out that back in the days without electricity everywhere they used similar systems as the Icy Ball and most pubs had wood fired ammonia fridges.
So the concept seems to be well know but long forgotten.
Climate concerns now allow for ammonia and propane to be considered again on a commercial scale, sometimes with better results than the usual ozone killers.
Someone with basic plumbing and welding skills can use an RV fridge as a template and simply upscale the system to whatever size required - getting it filled is the impossible part right now.
And before I go this route I really want an Icy Ball like system first, even if it is just for nostalgic reasons and a better understanding.
I know the above videos and for the destillation I have to say his way certainly works as advertised but not too many of us can afford or even obtain the equippment required.
Those freezers cost an arm and a leg around here.
A much easier way is to use a closed system and to utilise the fact that under pressure ammonia turns to a liquid as well.
Similar to an Icy ball you use two pressure vessels but the "cold one" also has a valve at the bottom to release the ammonia.
So first you destill concentrated ammonia in water, then you get it water free in an Icy ball.
Of course you need to cool everything with liquid propane before filling and collecting the ammonia but it give good quantities in a reasonable time.
Problem for me is that already ammonia in water at concentrations above 10% requires a decent purpose and corresponding permit to have it.
Pure and liquid ammonia as used for refrigeration purposes not only requires permits for that field but also strict restictions on storage, handling and documentation of usage.
To get such a permit I would first have to become a fully certified aircon or climate control technician LOL
My problem is not really making the stuff but the problems that go along with it.
In a residential area you simply don't want accidents with ammonia, not to mention that a simple destillation with the bottling after already causes enough stink to make your neighbours angry.
Might have to look into the methanol/charcoal systems instead but AFAIK their performance is quite poor compared to ammoina/water.
Ether should work better but comes with similar problems as ammonia.
I still think a cooling system that does not need electricity and can use the sunlight as a power source is still worth an Instructable but right now I am just stuck :(