Fridge insulation?

[Tim Good]

Whilst accessing the base of a chain plate on the deck I had to remove some cabinets that exposed the top of my fridge. In there is high density foam as you can see. Since I’ve removed all of this do you think it would be a good idea to replace it with a more modern alternative? Perhaps like super quilt the foil back?

Presumably the top of the fridge is less important to insulates than the bottom? Presumably the cold air sinks to the bottom and therefore dissipates out of the fridge more easily from the bottom?

 

[coopec]

What do you call a "more modern alternative"?

Polyurethane foam is the most commonly used insulation in refrigeration.

 

[Tim Good]

What do you call a "more modern alternative"?

Polyurethane foam is the most commonly used insulation in refrigeration.

Like some sort of Silver Backed Quilt with an air gap? Dunno.

 

[KompetentKrew]

From SwingCat's Fridge & Freezer Calculations for a Small Cruising Boat:

	E.g. Product Name	k (W/m.0K)
Vacuum Insulation Panels	Vacupor	0.004 (best insulation)
Aerogel based products	Spacetherm	0.013
Phenolic insulation	Kingspan Kooltherm	0.021
Polyurethane (PUR) or Polyisocyanurate (PIR)	Celotex TB4000	0.023
Extruded polystyrene	Styrofoam	0.027
Plywood		0.13 (least insulation)

If I recollect SwingCat used Celotex - see pages 11-12 of the PDF

Looks like you have a good space there that you can stuff full. I would cut small pieces of insulation (Celotex looks easy to cut and shape?) and eliminate the air voids.

 

[coopec]

Like some sort of Silver Backed Quilt with an air gap? Dunno.

I know what you are talking about. I think "Va-Q-vip Vacuum Insulated Panels " ?

I'd stick with polyurethane

 

[Tim Good]

From SwingCat's Fridge & Freezer Calculations for a Small Cruising Boat:

​

	E.g. Product Name	k (W/m.0K)
Vacuum Insulation Panels	Vacupor	0.004 (best insulation)
Aerogel based products	Spacetherm	0.013
Phenolic insulation	Kingspan Kooltherm	0.021
Polyurethane (PUR) or Polyisocyanurate (PIR)	Celotex TB4000	0.023
Extruded polystyrene	Styrofoam	0.027
Plywood		0.13 (least insulation)

If I recollect SwingCat used Celotex - see pages 11-12 of the PDF

Looks like you have a good space there that you can stuff full. I would cut small pieces of insulation (Celotex looks easy to cut and shape?) and eliminate the air voids.

Thanks. It’s already back fair full with the blue stuff which seems to be rather similar to Celotex?

 

[KompetentKrew]

Thanks. It’s already back fair full with the blue stuff which seems to be rather similar to Celotex?

Not my specialist subject, but it looks like it could be.

I find these pics when I google for "blue celotex": Celotex multi-purpose insulation board

 

[Perrycas]

Have been poking around on this myself lately. Previous owner put the fridge in - a 15L isotherm kit. Its poorly done and in an awkward place. A frij mechanic I spoke to years ago suggested that the rule was use a top opening and double thickness insulation material for the bottom. So I guess that means as thick as you can go all round, but thicker on the bottom. I would also imagine proximity to the hull to be important if a dark hull colour - I imagine need extra insulation between hull and box.
Have looked at the blue stuff but been told it wasn't the best/specific choice.
Aspen Aerogel products appear to be the best, specifically a product called 'space loft'. Not cheap but then the claims on 10mm are pretty high - and how big is a boat frijj?
Aerogel Australia app

Styrofoam RTM-X. seems good also composite panel insulation

 

[ithet]

I insulated an ice box with Celotex to make a fridge unit. I think it was 25mm board but I used as many layers as I could fit. Joined edges with foil tape.

 

[Perrycas]

I insulated an ice box with Celotex to make a fridge unit. I think it was 25mm board but I used as many layers as I could fit. Joined edges with foil tape.

What was the result, how well does it perform? Did you epoxy over the material?

 

[ithet]

What was the result, how well does it perform? Did you epoxy over the material?

The result was very successful, although I have since sold the my Moody which originally had an uninsulated single skin icebox (yes really!) with only the top lid insulated. I added the Celotex around the outsides of the box (under the worktop) when installing an Isotherm Kit. I stuck it all with 'Gripfill' adhesive and also used some low expansion foam to fill any gaps at the joins (but would probably not use this again due to the mess). I managed to fit at least two layers of 25mm on but got three on where I could and four underneath. The Celotex is already covered in alloy film, and I covered all exposed areas and edges with aluminium tape so that it was completely sealed. No further coating was carried out.

The fridge had a capacity of about 40l and could be kept very cold. All in all a vast improvement.

 

[Perrycas]

thanks ithet, good to know. hmm did your isotherm freeze stuff? I notice that mine has a container that lives t the top of the fridge which claims to be the place where you would stick frozens, but I cant figure this. Years a go I had a powered cool bin. I put a piece of plywood in with some holes drilled in it, that allowed about 10cm of space under it. That froze things.

 

[Kelpie]

Not a fridge, but when I converted a locker in to a cool box I went to a website specialising in plastic boxes and found the best fit for the space, leaving a minimum 50mm all round, and then that became the wipeable inside lining. Celotex/Kingspan pieces for the bulk of the insulation all glued together and gaps filled with low expansion foam. If you make a mess with the foam, the trick is to let it completely set and then pick off the offending blobs. Worst thing you can do is to try wiping out up whilst still gooey!