Making my own boat fridge.

[firstascent2002]

I'd love a fridge on board. In the small galley, right next to the taylors stove (perfect position for a fridge I know) there is an uninsulated locker accessed via lifting a hatch in the galley work surface. On top of this the paraffin pipe to the taklors runs through the locker.

So on the face of it, Its not IDEAL for a fridge but it is the only place in the boat that I could build one in. The evaporator would be somewhere under the cockpit sole. (1.5 m away). If I wanted to try and make this work, I have a few things to acheive.

1) Insulation. My first thought was polystyrine pannels from wicks but there must be somthing with better performance out there. I really don't want the sides to be more than 3" of insulation except the stove side which I have allowed 4" for. Any more than that and the lack of internal space in the fridge would make the project a waste of time. So any suggestions on what to insulate with? Once the insulation is in place then I'll glass it in to make the whole thing water tight. I suppost I should have a plug at the bottom as well for umska.

Second question is about the taylors pipe running through the system. Paraffin won't turn to wax at fridge temps right? If it does then the taylors has to burn wax and that essentially makes it a candle! /forums/images/graemlins/laugh.gif

So the long and short of it ...How do I make my fridge.

J

 

[Cliveshep]

Don't know about making a fridge, but modern fridges are insulated with a (approx) 50mm thick foil-backed polyurethane foam slab, sold in varying thicknesses as "Celotex" in the Construction Industry. "Filler foam" also used in the same industry can be used to fill small voids, it needs air to cure it as it is moisture-cured from water vapour in the air - should have a lot of that in a boat! Tape joints with the silver foil sticky-backed tape also sold to seal joints in construction jobs. Hope that helps.

 

[Metabarca]

check this out: http://www.isotherm.com/en/index.html?fixframe=1&

 

[Lizzie_B]

Have found this stuff very easy to use and very effective.
http://www.e-marine-inc.com/products/refrigeration/panels.html

Converted my cool box using a 'Norcold' compressor and plate kit (includes all hoses and connections), but found the insulation totally inadequate on the original cool box.

Used this stuff to upgrade the the insulation and now will make ice. Box remains cold for about 2 -3 days whe power off.

Filled in gaps with expanding foam and sealed joints with sticky back aluminium heating duct tape.

 

[firstascent2002]

that looks ideal. Did you order it from the states or did you find a uk supplier?

J

 

[wanderlust]

Kooltherm or similar polyeurathane insulation is twice as efficient for the same thickness as polystyrene. I used 4 inch thick foil faced. Made the box out of 1/8th ply coverd in formica and glassed the edges on the outside.

 

[misterg]

Foil faced polyurethane from the Builders' Merchant is a better insulator than polystyrene, and is easier to work with (It saws to clean, square edges, and it surprisingly strong) Kingspan or Celotex are the big brand names (equivalent performance). I think I was paying about £3.20 per 600mm x 1200mm x 25mm sheet when I bought it for our extension. The BM will probably only stock the thickness that building regs requirements require (probably 30mm, now for cavity walls) but it is made in many different thicknesses. You could also try these people if you're having trouble (no connection).

FWIW, I would make it out of several layers of 25 or 30mm board, with the joints in each layer staggered - easier to get a good, tight fitting assembly. By the time you've fitted 75mm of this, the performance of the cool-box will be more limited by how good the joints, lid, etc. are.

I would also re-route the paraffin pipe outside the insulation, because it would be a major source of heat leaking into the fridge.

Andy

DOH! Must type faster.

 

[misterg]

[ QUOTE ]
Have found this stuff very easy to use and very effective.
http://www.e-marine-inc.com/products/refrigeration/panels.html


[/ QUOTE ]

I've just seen the price!!!

$250 for 3 sheets of 50mm polystyrene!!! (<1m x <0.5m) that's over 100 quid!

Tell you what, I'll do you foil backed polyurethane at the same price.

Andy

 

[Lizzie_B]

From the states, but you maybe able to find a UK supplier. I couldn't bothered to look /forums/images/graemlins/grin.gif

 

[Lizzie_B]

It is very different from anything I've ever seen described as polystyrene in this country. Much denser.

My fridge is wedged between the engine and cooker (only space for it) and this stuff makes a huge difference.

My previous boat's fridge was insulated with what I'd normally call polystyrene and it was next to useless by comparison.

The sheets are pretty large. I had one whole one left over!

Whilst not cheap, for the difference it made I thought it was money well spent - although it was cheaper when I bought it.

 

[tobble]

My neibour used kingspan on the reccomendation of the compressor supplier, don't know how it has performed right now...



[/ QUOTE ]Tape joints with the silver foil sticky-backed tape also sold to seal joints in construction jobs.

[/ QUOTE ]

my neighbour also did this, and I think it's a bad idea. a stip of alu (very good conductor) across the insulation will form a 'cold bridge' and will reduce the effectiveness of the insulation, I suspect by a quite significant amount, for a shape with high edge length:volume ratio (i.e. a small cuboid) If you are worried about moisture ingress to the foam, I'd paint it with epoxy, possibly with some fine tissue fibreglass.

 

[kds]

"a stip of alu (very good conductor) across the insulation will form a 'cold bridge' "

I can't see it - the alu is all on the same side of the insulation. so where can it "bridge" the heat to ?
Ken

 

[William_H]

A fitted fridge would be very good especially if you can get a water cooled condenser. Rather than the usual air cooled type.
However you could possibly save money and troubel by cutting out the cupboard area and fitting a complete top loading fridge. This can be removed for servicing (we hope not) or even taken home for filling (although they are usually too heavy when filled) olewill

 

[tobble]

Ken:

I think I have failed to explain properly... kingspan or similar comes with one or both 'main' faces covered in a foil, the theory being that a nice shiney surface will reflect radiant heat back and thus increase insulation. Also available is foil in a sticky tape form, slightly wider than the depth of the standard insulation. the idea is that one sticks the tape over the exposed edge of the foam to water proof it, but a) I don't think it would be seriously water proof, and b) you end up with a strip of alu thermally linking either side of your insulation. in fact now I think about it, you are thermally connecting your nice foil coatings, which will reduce your insulation's effeciveness megalots.

IMHO don't bother with the foil at all, it needs a decent size void, such as a loft, to reflect back into to work at all!

 

[Lizzie_B]

Oh! and unlike what we think of as polystyrene, this stuff is easy to work with.
Cuts to a clean smooth ,square edge with a fine saw.