Thread: 12v Compressor Fridge Build

Looks good. - A few questions.

- How did you attach the saddles that hold the copper pipe to the box? Can't see any penetrations so not rivets I'm assuming.

- what size copper and how many metres did you end up using?

- what compressor did you use?

Got any pics of the compressor and controls hooked up?

Cheers - Gav

bacicat2000
The saddles were attached using 3M VHB DS tape, only need to stay in place until the foam is poured in. Not shown in the images is a product to aid heat & cold transfer, it is a past that is heavily impregnated with aluminium, cannot remember the name.
The copper size is 6mm for the heat transfer outer part & 4mm for the cold transfer inner.
The length will depend on the size but i used 18M of both sizes.
The compressor is a Danfoss as mentioned.
More coming!

The inner was then placed inside the outer.
This next step is very important, once the two sections were in place i used 75mm thick ply both inside & outside to control the expanding 2 part fridge foam. This needs to be done in many small parts rather than one big batch as things can go very bad, the foam generates extreme pressure during curing. Making the foam is very critical when mixing the two parts.

Once the foam has cured for 48 hours the excess can be cut level with the sides. For the lid, that was also made from two alloy trays that fit inside one another, using the outer fill with the expanding foam, after curing cut clearance on all 4 vertical sides of the outer then fit the two section together. These were boned together using Fixtech polyurethane.
I had a plastic company make the top white section, this is another critical piece of the fridge. This cap cannot be metallic as the cooling & heat transfer will be fighting each other, so it must be non metallic.

Cheers
David

I do not have a detailed image of the engine room, that will require removal of the fridge & that will happen in a couple of weeks.
The fridge seal is a simple D seal that has sticky on the flat side, with mitred corners & a little black Fixtech along the mitre works very well.
The hinges are very simple S/S ones, the hinges are all nut-serted into the body & lid. There is a 300mm long low out put LED light strip which is on all the time.
The lid is locked in place with a simple office cupboard push latch, have not had trouble with it.
Everything is controlled with a digital thermostat on the face of the cabinet.
The other problem i had was finding a half smart Fridge to connect all the pipes & gas the thing correctly.

If i was to build another i would make the walls thicker 70mm would be much better & the fridge would be much more efficient.

Hope this helps anyone looking to build one.

Cheers
David

not having a clue how these things work, I didn't realise that there was two heat transfer coils, one for cold, one for heat on the inner/outer surfaces of the fridge, of course it makes perfect sense now I see it though! dead simple really...

Hi,
nicely thought out.
Much neater using the out side as a heat dump rather than a coil and fan. Like EchiDna above, a whole new concept has been realised. Thankyou.

cheers

This design is not new its been around for a very long time. I liked it as its simple, robust & if done right very efficient.
It just takes i bit of time to perfect, to increase the efficiency of mine i should have made the insulation thicker, closer to 70mm. Just the difference from 50 to 70 saves loads of that precious 12v power.

Cheers
David

Nice write up and top job

Originally Posted by Witchdoctor

bacicat2000
The saddles were attached using 3M VHB DS tape, only need to stay in place until the foam is poured in. Not shown in the images is a product to aid heat & cold transfer, it is a past that is heavily impregnated with aluminium, cannot remember the name.
The copper size is 6mm for the heat transfer outer part & 4mm for the cold transfer inner.
The length will depend on the size but i used 18M of both sizes.
The compressor is a Danfoss as mentioned.
More coming!

The inner was then placed inside the outer.
This next step is very important, once the two sections were in place i used 75mm thick ply both inside & outside to control the expanding 2 part fridge foam. This needs to be done in many small parts rather than one big batch as things can go very bad, the foam generates extreme pressure during curing. Making the foam is very critical when mixing the two parts.

Once the foam has cured for 48 hours the excess can be cut level with the sides. For the lid, that was also made from two alloy trays that fit inside one another, using the outer fill with the expanding foam, after curing cut clearance on all 4 vertical sides of the outer then fit the two section together. These were boned together using Fixtech polyurethane.
I had a plastic company make the top white section, this is another critical piece of the fridge. This cap cannot be metallic as the cooling & heat transfer will be fighting each other, so it must be non metallic.

Cheers
David

Thermopaste,works well,but if you are not careful,seems to end up everywhere