Insulating stand-alone, side-opening fridge

[SVNeko]

I have 2 refrigerators and one freezer on this boat - all isotherm keel-cooled, side-opening boxes. My 720w of solar is having a hard time keeping up with their draw in warm water. Does anyone have experience in insulating the exterior of these types of fridges? These are complete units (not insulated iceboxes) built into cabinetry and have a bit of space around the sides and top.
Thanks

[JPA Cate]

If you coated 'em with mold-release, and then foamed in with the spray foam around them, that might help. But with side openers, you're always letting a lot of the cold out when you open the door. How I'd try to address that is with a large piece (to fill the opening) of medium weight clear pvc material (as in dodger windows), with a bolt rope sewn to the top, and slashes every 2 inchces or so, so that you can reach in through it. I would reinforce the top of the slashes with a strip of the same material, glued on with pvc pipe glue. You'd mount bolt rope track on the top of the inside of the enclosures, with enough room to feed in the sheet. We used to use this in the US in grocery stores to keep down power usage, but it seems to have fallen out of favor.

Or perhaps add another solar panel.

[Richard Kollmann]

Originally Posted by SVNeko

I have 2 refrigerators and one freezer on this boat - all isotherm keel-cooled, side-opening boxes. My 720w of solar is having a hard time keeping up with their draw in warm water. Does anyone have experience in insulating the exterior of these types of fridges? These are complete units (not insulated iceboxes) built into cabinetry and have a bit of space around the sides and top.
Thanks

Refrigeration is the process of removing heat and this is sometimes more important than adding insulation . I would test my installation first by comparing its exterior surface temperature against surrounding cabin air temperature. This test needs to be done with box at desires operating temperature. If insulation’s exterior surface temperature is more than 5 degree F colder than surrounding air temperature adding insulation may help especially if there is a noticeable difference or condensation.

Refrigeration system’s performance depend more on process heat disposal than insulation. I assume your three units have Danfoss Compressors and through hull coil Isotherm condensers intended to dispose of all process heat. Have you cleaned these through hull coils recently? Energy efficiency depends on these condenser coils disposing of heat into seawater. To see if a through hull is efficient check temperature of refrigerant line coming out of condenser coil and it should be only slightly warmer than seawater temperature. While line interring through hull condenser will be hot.
One way to improve heat disposal and daily energy consumption on these Isotherm systems is to reduce compressor speed. A lower speed that will still satisfy desired box temperature can improve performance by running compressor longer at less amperage work per hour allowing more time for condenser coil to dissipate heat.