Heat Absorption Fridge

[101RRS]

I was given an old Finch heat absorption 3 way camping fridge/freezer. (looks about 35-40litre) - No fan or compressor.

I have had it running on 240v but it only gets down to about 5 degrees - is supposed to work as a freezer. Really doesn't perform any better than my electric cooler. The element does get cold - and frost does develop on it but overall the fridge does not get very cold.

I do not know much about these fridges except that do take a long time to get temps down, do not work well on 12v, and on gas the burner can wax up.

Any ideas what I can do to get this thing to work at least - sort of OK - can the coolant be changed or recharged.

If I do decide to persist with this, it will be basically run on gas which I haven't tried as yet - I understand they work about the same on 240v as they do on gas.

Appreciate any advice.

Thanks

Garry

[Blknight.aus]

what you do is empty it, put it on a harshly sprung trailer, strap it down well and take it for at least an hours drive. Preferably over a corrugated road.

then spend 10 minutes rolling it over and over and over and over, spin it on all 3 axis...

then start it up again. Providing the seals and the insulation are up to scratch (you checked them first right?) it will now work much better.

If you cool them down before switching them over to 12v and dont open or close them too often they do alright on 12v but not as good as a compressor fridge.

Ive got the "how it works" type docs on the basic design of these fridges here somewhere.

eyeball here its got a great layout of how it works.

http://web.archive.org/web/20040417020411/http://www.cam.net.uk/home/StKilda/electrolux.html
the logic behind shaking and rotating it lots is this.

IF left for a prolonged period with no thermal differential across its components (ie off with the door open like you would for storage) the liquids in the traps evaporates and moves from where it should be into the storage areas so the cycle cant start properly. the gases and liquids don't totally like each other either so will eventually seperate out of solution. shaking the fridge agitates the fluids so they get mixed up with each other, rotating the fridge gets some liquid back into the trap areas where its needed. Once the cycle starts it sorts itself out into the correct mixes and locations.

[scarry]

Once again dave is Spot On.The other thing to remember is that these types of fridges were not real efficient,no where near as efficient as 240 volt compresser fridges.I also doubt it is a freezer.

What you are getting out of it is not real bad,depending on ambient temperatures.

Another thing poeple do is leave them upside down for a week,(turned off),and then try it.This also stirs up the chemicals.

[101RRS]

Dave- Paul

Thanks for the information - that is great stuff - the fridge has been sitting for a few years - it has a freezer logo on it - hence the thought it might also be a freezer.

Turned it upside down and around a bit and it managed to get to -5 overnight but not cold enough to freeze water - maybe I need a new thermometer.

I used a kero version of a free standing fridge when I was a kid and I remember it worked pretty well.

I will leave it running for a while to give it time to settle down and see how it goes. I am surprised these were still being sold in the mid 80s - then I had my first 12v cooler/warmer about a 10th of the price of a fridge and the cooler's perfromance seems to be on about par with this type of fridge.

Thanks for the information.

Cheers

Garry

[ladas]

Dave- Paul

Thanks for the information - that is great stuff - the fridge has been sitting for a few years - it has a freezer logo on it - hence the thought it might also be a freezer.

Turned it upside down and around a bit and it managed to get to -5 overnight but not cold enough to freeze water - maybe I need a new thermometer.

I used a kero version of a free standing fridge when I was a kid and I remember it worked pretty well.

I will leave it running for a while to give it time to settle down and see how it goes. I am surprised these were still being sold in the mid 80s - then I had my first 12v cooler/warmer about a 10th of the price of a fridge and the cooler's perfromance seems to be on about par with this type of fridge.

Thanks for the information.

Cheers

Garry

These ammonia/water or lithium bromide/water fridges are still manufacturered to this day. Mainly for outreach stations where there is little or no electricity, and where the use extends over and above what a solar fridge can do.

Many developing nations remote clinics use them to store innoculations etc.,

Dave has it spot on, and the aggitation with the old ammonia types works well - the later lithium bromide units are not so suseptable to the chemical separating out from the solution.

[Tank]

Aldi have a 3 way 50L fridge on sale at the moment for $299, Regards Frank.

[Blknight.aus]

if your trying to freeze something with it you need a lot of patients....

they do get cold but they dont have a lot of heat capability...

sort of like using a 2.25 diesel to do the job of a 4.9l V8... yes you can but it takes a lot longer...

double check the seals and if its started working crank it up and leave it run

while its running open the door every now and then for an hour or so to let the heat exchanger to de-ice. this promotes the flow of the system and will eventually get it running at peak efficiency.

the better its ventilated at the back and the cooler you can keep the area the better.

[101 Ron]

Hi Garry
I purchased a Finch Fridge exactly like you described many years a go new .
It permantly lives in the back of the 101 landy as I just dont bother to take it out after camping.
They are still made and sold under different brand names.
My missus put her **** on it one day a broke the lid.
I managed to buy a new lid even though the fridge was more than twenty years old.
Dont worry about using it on 12 volt as it will screw batteries and wiring and will not work well.
Performance on 240 volt is OK if it runs for a long time and this can be thermostat controlled whisle 12volt can not.
On 240 volt it can be used as a bar fridge.........but dont expect very quick chill down,it takes a long time.
If the fridge is already full of cold cans and you are taking them out one at a time ......no problem.
On gas is where these fridges shine as they will run for two weeks on a large primus type bottle and the fridge works best on gas.
Mine will freeze, but only if the surruonding temp is not above 25 degrees c.
These fridges can not pull down the temp much more than 20 degrees than the surroundings.
When I use to go out west and the temp got to 40 degree c the fridge was worthless with a internal temp of around 20 degrees c.
On the east coast they work OK for 90% of the time.
Stactic camping in your part of the world no problems.
Compressor fridges kill a finch fridge in outright performance over shorter periods and the finch is not any where near the running on 12 volt.
My finch is soon to be replaced by a chinese compressor fridge went it comes out of laybuy.
The engals in my family are more than 30 years old and still going strong.
Whisle the finch fridges seem to kept working too it is only suited to camping for a long period of time in one spot.
Remmember the finch has only a small cooling plate and this is why it takes a while to chill down.
Ron

[abaddonxi]

In other threads it's been suggested that you get a 12v computer cooling fan and stick it onto the fins on the back of the fridge, should make a decent bit of difference.

Electrolux make a range of them for hotel rooms; don't need too much cooling and very quiet.

Cheers
Simon

[101RRS]

Hi Garry
It permantly lives in the back of the 101 landy as I just dont bother to take it out after camping.

Remmember the finch has only a small cooling plate and this is why it takes a while to chill down.
Ron

This was a freebie so I am not really prepared to ditch unless absolutely necessary. While I appreciate running it on gas is not a good option for most cars - I figure that in the back of a 101 will be fine given the built in ventilation.

You are right about the cooling plate - does freeze but the there are no fins to allow efficient heat transfer - I might add some alumium cooling fins that are used on electrical equipment - cheap from Jaycar and see if cooling transfer is better.

I will also take the back off and clean it all up - should also work OK.

It is maintaining -5 to 0 so from what has been said here - is working well. I will try on gas on the weekend and see how we go.

Cheers

Garry

[101RRS]

In other threads it's been suggested that you get a 12v computer cooling fan and stick it onto the fins on the back of the fridge, should make a decent bit of difference.
Cheers
Simon

I will have a look at the cooling fan option after I have cleaned it all up and put some cooling fins inside.

Thanks

[101 Ron]

The three way fridges used on caravans find greater performance with computer fans .
I am certain this will not help the finch fridge .
there is plenty of ventillation in the back of it.
I find packing gear around it in the back of my vehicles doesnt affect the performance to any noticeable degree.
Operation on gas is the go !
Mine I leave on gas whisle driving in the back of the defender or 101 with no problems.
The only common fault which I know of is the sliding plastic cover over the controls can melt .
I never cleaned the burner on mine or had any problems other than the gas regulators on the bottle playing up.
Some times they can be a bit hard to get lighted.
Learnting where to adjust the gas control knob takes time too.
As made they came with small ice cube trays which sit on top of the cooler plate.
These small trays full of water or ice improve the surface area of the plate and help the whole thing work better.
These trays most likely would have been lost ?

[101RRS]

Well the fridge is working OK on 240v - now maintains -5 and is trying hard but not quite freezing 400ml of water (ice has formed but not frozen through) - works just a tad better than my 12v cooler/warmer.

Gas will seem to be the go and I will try that this weeked.

Thanks to everyone who has provided advice and input.

Garry

[ladas]

Well the fridge is working OK on 240v - now maintains -5 and is trying hard but not quite freezing 400ml of water (ice has formed but not frozen through) - works just a tad better than my 12v cooler/warmer.

Gas will seem to be the go and I will try that this weeked.

Thanks to everyone who has provided advice and input.

Garry

Gary, also check the door seals properly - it's amazing the amount of energy that can be lost through a badly sealed door.

If it's going to be a bush fridge - think about putting clamp type closers on the door - not attractive but bloody effective.

[bruiser69]

With Absorption fridges it is critical that they are level.
Get a small spirit level (circular with bubble in middle)& epoxy to top.
Get a 12V fan from an old computer power supply or new from Jaycar & mount under middle of evaporator (the finned unit you can see thru vents at top of fridge).
Mount so that fan blows up towards centre of evaporator. These 12V fans draw only 150ma but dramatically improve cooling efficiency of absorption fridge even when run on gas. Mount a socket on rear and wire to fan.
A cord with cig lighter plug completes setup. Power drain is so low that you can leave fan plugged in for days without any serious discharge to battery. 24hrs X.15A is only 3.6AH.

Cheers..B

[Bushwanderer]

Hi Bruiser,

Any chance of pics?

Best Wishes,
Peter