Turning a locker in to a fridge/freezer

[Kelpie]

OK. I've got several sheets of Kingspan, I have a 12v kit from Penguin refrigeration, and I'm all set to start the job,
First question- is it OK to go hard against the inside of the hull, or should I leave an air gap? I was thinking of using expanding foam to glue the first layer of Kingspan in place, and build up layer from there to create the box. This will give the most insulation possible.
OTOH is it worth putting some sort of packer material (maybe just blocks or strips of Kingspan?) under the first layer of insulation? That would allow condensation and bilge water to drain freely, instead of getting trapped in any air pockets between the insulation the hull. I would lose a little insulation but not enough to worry about.

 

[William_H]

I would do as you suggest attaching insulation directly to the hull inside surface. ol'will

 

[KompetentKrew]

I don't think the "air pockets" will be significant, will they? Not if you just fill the space with celotex and expanding foam.

In case you haven't seen this PDF: http://www.swingcat.co.uk/what/fridge_freezer_calculations.pdf

 

[coopec]

I would definitely leave an air gap between the hull and the fridge/freeze box: air must be allowed to circulate.
The fridge mechanic made that directive very clear to me when I was designing my installation.

He said that was a common mistake on boats he worked on in Darwin where the sea water temperature
could be 33C and the insulation was not able to handle the heat transmission. There must be an air gap to allow circulation of air to take warmer air away and bring cooler air in.

 

[colind3782]

He said that was a common mistake on boats he worked on in Darwin where the sea water temperature
could be 33C and the insulation was not able to handle the heat transmission.

I doubt that's an issue on Skye!

 

[coopec]

I doubt that's an issue on Skye!

Actually that had crossed my mind! ?
Maybe you could have a sea-water cooled fridge?

 

[Kelpie]

I doubt that's an issue on Skye!

Good point but we are no longer in Skye. Currently heading for the Med and plan to also cruise the Caribbean, maybe even the Pacific if all goes well.

 

[geem]

OK. I've got several sheets of Kingspan, I have a 12v kit from Penguin refrigeration, and I'm all set to start the job,
First question- is it OK to go hard against the inside of the hull, or should I leave an air gap? I was thinking of using expanding foam to glue the first layer of Kingspan in place, and build up layer from there to create the box. This will give the most insulation possible.
OTOH is it worth putting some sort of packer material (maybe just blocks or strips of Kingspan?) under the first layer of insulation? That would allow condensation and bilge water to drain freely, instead of getting trapped in any air pockets between the insulation the hull. I would lose a little insulation but not enough to worry about.

How thick do you intend the make the insulation? We used 100mm on sides, 150mm on bottom and 100mm on top. If you can achieve these thicknesses you don't need an air gap. Mine has been working well and economically including 30degC water temperature in Bonaire and Curacao in the Caribbean

 

[DanTribe]

Just a thought. I lined the locker space with 50mm Celotex and used a preformed liner. Then I used expanding foam to fill the remaining space.
I should have realised that the liner would then float, but I didn't! Desperately trying to find sticks to strut it down, there was a lot of bouancy in that liner. I could have filled it with water, but I panicked.

 

[Kelpie]

Hopefully 150mm in most places. The idea is to try to run a small freezer compartment and I'm willing to trade off volume for insulation.
(Currently carting around several large sheets of Kingspan in our spare cabin... I need to get on with this project just to get rid of them!)

 

[geem]

Hopefully 150mm in most places. The idea is to try to run a small freezer compartment and I'm willing to trade off volume for insulation.
(Currently carting around several large sheets of Kingspan in our spare cabin... I need to get on with this project just to get rid of them!)

We used the large elliptical evaporator plate as the freezer, sealing one end and using the other end as access via a foam lid, so the freezer is actually fully inside the fridge rather than created at one end. The freezer is 10 litre capacity. Plenty for us. It also ensures that the freezer space isnt relying on the insulation since it has the warmer space of the fridge around it