1930's (?) GM Frigidaire

[emeritus]

Ammonia is one of the working fluids (along with water and Hydrogen) of the compressor-less absorption (Elelctrolux) fridges. We had a couple of gas fridges that operated on that principle, as well as a Gas/12v DC one in our old campervan, but had no problems with them. The Electrolux fridge in the shared flat my wife was renting before we got married sprang a leak, and they had to put it in the garden due to the smell.

Darren, you will find that the Odhams book has a chapter specifically dealing with motors for fridges and washing machines: it was too long to include in the scan. Happy reading!

[Andrew B]

We never see absorption fridges anymore. Gas and electric absorption fridges in houses were quite common at one time.

Anyone got an idea why?

Andrew

[Refugee]

Gas fridges are still used in locations that only have solar or petrol power.
The older sister of my other half had a place in Spain where mains power was offered by a dodgy supplier and they kept the gas fridge and did not get ripped off.

[emeritus]

I guess that the expense of putting in a gas point would be one reason, and the only real market for a gas fridge in recent times would have been replacement of an existing one. As they have no moving parts, replacements were not frequent. On the other hand, I they did do mains electric models: my recollection is that they were significantly more expensive than compressor models, so would only be bought by those who appreciated their absolutely silent operation. Possibly EC energy efficiency regulations may be a factor? Thermodynamically, the absorption cycle is less efficient than the cycle that uses a compressor.

In the house where I grew up in the 1950's, gas was the only realistic option. The only electricity in the kitchen was a single 15A socket (no electric light either, other than a bulb in a BC socket paralleled with the 15A socket and intended for a pilot lamp). Circa 1958, when dad decided we could afford a fridge, as he was a gas fitter for the gas board and got employee's discount, it was simpler for him to install a new gas point himself than to pay to have a power point installed in the kitchen. My first house came with a gas fridge that I brought to our house when we got married, and I put in a gas point in it for it myself: it was legal to do so then.

[Peter.N.]

The old absorption fridges very common in my youth used ammonia, never had one leak but you could recondition them when they stopped working by turning them upside down for a while which allowed the fluid to run in the reverse direction and cleared the pipes out.

Ammonia was the basis of smelling salts when I were a lad.

Peter

[Herald1360]

Efficiency being what it is regardless, given the energy cost differential between gas and electricity supplies, which is cheaper to run- a typical electric compressor fridge or a gas powered absorption one?

[Peter.N.]

I would say a compressor type. You are using heat to circulate the condensed gas in an absorption fridge which needs something 100 watts and is running for far longer than a compressor and a domestic one uses less than 100w for a much shorter time and is much more efficient.

Sorry, missed the bit about the gas but I would still say a compressor type is cheaper to run.

Peter

[Herald1360]

I've done some googling, and it seems that electric compressor type is the cheaper. In a nutshell, electric compressor coolers are about 7x as efficient as absorption coolers, so with gas at a third the cost per kilowatt hour the electric type costs just under half as much to run.

An fascinating (to me at any rate) diversion.

Getting back to the old Frigidaire, a similar comparison of running costs would be interesting. Are new fridges more efficient because of better insulation, better cooling unit performance or mixture of the two? Would the capital cost saving vs buying a new fridge cover the energy cost difference over the expected life of a new fridge?

[Zelandeth]

It will be a combination of better insulation and compressor design. The use of thinner metals and such in the condenser and evaporators, while making them more prone to failure over time, does reduce their thermal mass and make them able to bring the fridge down to temperature more quickly. Plastic lining helps there as well, as it means that the interior of the fridge itself also has less thermal mass than the old metal lined ones.

There are a few "drop in" replacements for R22, R417A and R422D from memory, but I'd double check that! Being this old I imagine it will have proper service ports, so should be easily dealt with by any competent refrigeration engineer.

So long as it's been in regular use it shouldn't cause you any problems I reckon. The only things I'd do would be to check the condition of the wiring as that may be decomposing, and it might not be a bad idea to add a thermal cutout of a sensible rating on the motor casing as it's not a given that something of this age will have a built in cutout.

A friend of mine has one of the GE ones with the sealed compressor/condenser on the top and it's still doing sterling service in his games room as the drinks fridge, having never had anything done to it save for a respray. I still kept being surprised by how incredibly quiet it was in operation. Haven't seen them in a few years now, but I've no reason to believe that it's not still going.

[Peter.N.]

I would also think that the efficiency of the sealed unit would be somewhat higher than a separate motor and compressor with a belt drive and probably twice as many bearings.

Peter

[Andrew B]

I seem to remember the flame on the gas fridge was only small, more like a gas pilot light. In an out of the way place with no services maybe a paraffin lamp/wick or a candle would be sufficient to run it?.

No moving parts should mean it would be more reliable than the compressor type of fridge.

Andrew

[Peter.N.]

I think you could get paraffin versions, I have vague memories of them - but then O have vague memories of most things nowadays.

Peter

[broadgage]

Originally Posted by Andrew B

We never see absorption fridges anymore. Gas and electric absorption fridges in houses were quite common at one time.

Anyone got an idea why?

Absorption fridges are still made for use in hotel rooms, they are favoured for this application due to being near silent.
The 3 way fridges used in caravans are also absorption types since the required heat input can be obtained from a 12 volt heating element, or a 240 volt element, or a gas flame.

Apart from these special cases, they find little favour these days due to higher running costs.

Originally Posted by Peter.N.

I think you could get paraffin versions, I have vague memories of them - but then O have vague memories of most things nowadays.

These were made until recently and may still be made, used to be popular in the more remote parts of Australia, and also used for refrigerated vaccine storage by healthcare workers in developing countries.

Now largely replaced by DC compressor fridges that are battery powered with the batteries being charged from solar panels.

[Andrew B]

Aha, another thing that we have overlooked is the "Peltier" devices, they would obviously be silent, but very inefficient.

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

Andrew

[Dazmond]

Hi Folks,

Sorry for the late update i've been rushed off my feet, thank you all for you replies.

I've attached a few shots of the internals of the fridge, unfortunately access is still limited where it's stored until next week so these are the best I can get for now.

I've not plugged it in yet until I can give it a proper inspection, but as you can see from the label it uses Freon which may or may not be an issue depending on how much life is left in it?

[Dazmond]

A few more.

PS. The red label on the front of the compressor doesn't have anything on there, I think by the looks of it the door could do with a new seal though…

Many thanks,

Darren.

[Dazmond]

Originally Posted by emeritus

Darren, you will find that the Odhams book has a chapter specifically dealing with motors for fridges and washing machines: it was too long to include in the scan. Happy reading!

The book has been dispatched and should arrive tomorrow, really looking forward to having a read, this is definitely a project where I need to educate myself a little first!

[Herald1360]

That looks like a sealed compressor unit so unless there's a hole in the piping/radiator somewhere it should still be full of whatever Freon was originally installed.

[Zelandeth]

The term freon refers to a number of refrigerants, R12 in this case. It's still quite commonly used to just generally refer to refrigerants in general by those who don't know that there are a myriad of different types.

So long as the system is gas tight it's not a problem, the refrigerant doesn't really have a "shelf life" so provided there are no leaks and the compressor hasn't suffered a mechanical or elecrical failure, it should work.

That looks to be a reasonably early example of a hermetically sealed compressor, so you should have less risk of leakage as the troublesome mechanical motor drive to compressor seal is dispensed with. Does mean by definition of being a sealed unit though that if there is a problem, there's not much that can be done other than replacing the compressor.

Been a while since I've seen anything with the Sterne name one, it must be pretty old given that the L Sterne company went into liquidation in the 60s .

[Dazmond]

Thank you for this - I know this may sound like a silly question to those in the know, but if it is leaking will this be audibly / visually obvious?

The first job will be to inspect the electrical side and also check for any obvious signs of corrosion or potential leaks, in terms of firing her up for the first time i'm wondering if it would be beneficial to use the variac - but would introducing an initial low voltage cause any problems for the compressor?

I'll that dirt and grime everywhere is irritating me, I can't wait to get it all off!

Yes age wise the seller told me from what can she remember her grandmother bought it in 1936!

Many thanks,

Darren.