+xNow that we are cruising in warm water for the next few years I have been investigating how we might make our freezer more efficient. We have 75mm foam insulation around a freezer box built into our galley. It was fine in cooler waters but our compressor is working hard to keep it cold in the tropics. The only realistic way of improving insulation is to line the compartment.Has anyone done this using retrofit PanasonicU-Vacua™ Vacuum Insulation Panels? The smallest panel I can find is 12”x15” and a 1” thick panel appears to have phenomenal ‘u’ values. It would be great to hear from anyone who has tried to retrofit similar panels and in particular, was it worth it and how they did it?Simon
Hi Simon,
The following was written to a Valiant 42 group, but has all that is necessary information. I am fortunate to have quire a large freezer. We still us this (15+ yrs or more) even though we have been in cold waters lately.
Come back with questions/comments etc.
My best, Dick Stevenson, s/v Alchemy
Dear List, last edited, 09-’23
I have a V42 reefer/freezer box set up which I have always considered one of the low points in Valiant’s design history. In other words the design is only adequate in respect to Valiant’s usually superb design decisions. I hated the initial set-up for live-aboard at-anchor use and when I yanked out the holding plate found a cavernous space. We still use this space as a freezer and installed the evaporator plates high on the fore & aft sides. We knew we lost lots of heat through the bottom into the quite warm water we were cruising in at that time, so we started adding layers of insulation (to the freezer) on the bottom and sides (up 12 inches or so to the bottom of the evaporator plates). We have used 1. closed cell alum faced 3/4 inch hard-board insulation (from Home Depot), 2. Armourflex (now perhaps K-Flex), a black closed cell flexible pad easily cut and worked in ½ and ¾ inch thicknesses, 3. Reflectix, insulation like bubble wrap with alum foil on both sides, and 4. Thin very tough plastic (made for flexible cutting board uses).
The hard board is the first layer on the bottom & sides, (on the flat bottom surfaces- frig & freezer- there are dry deck- nipped somewhat thinner- to keep frozen items away from standing water/spills) cut in multiple pieces to fit the space, duct tape edges to protect the foam, and butted together (not connected). The hard board is the bottom layer, then a thick strip of Armourflex, then the side hardboards. This establishes a stepped overlap junction to help insulation.) Then there are 3 long strips of Armourflex cut to butt into the sides and go up as high as possible on the outboard side and starting at the bottom of the removable dividing insert between frig & freezer in my V42-128 design.
Then I taped together the thin (1/32 inch) cutting board plastic sheets to form fit the bottom and protect the Armouflex foam from abrasion from stored frozen items.
Then I made a form fitted Reflectix “bin” (kind-of like a bucket) to go low down and held together with duct tape as a last insulating item and to catch spills/drips.
Finally, I took 2 Reflectix sheets and taped the edges together with duct tape and this “lid” fits perfectly (and slides into) a groove made by the top of the evaporator plates and covers the whole top of the freezer (just under the lid) and is flexible enough to lift for access to frozen goods when the hard top is opened. The dividing insert (freezer from frig) does not have beefed up insulation as the cold will just migrate to the frig (eg not lost). There are no spillover holes in the insert (filled in when I went to 2 separate independent cooling units) to cut down on moisture getting into the freezer and onto the plates.
We have used this configuration for almost 2 decades. We lost a fair amount of space with this insulation in a design which is luckily actually enormous (after removal of the huge cold plate) for a 40-foot boat, so we rarely miss the lost space. We use our freezer a lot.
Another worthy addition was to have a “condensation” pad. Ours was a sheet of ¾ inch Armouflex which was cut to fit the top counter over the frig and freezer. This stopped completely the occasional condensation on the counter tops on hot humid days, added to the insulation of the refrigerated areas and was less of a pain than we thought it would be: easily folded to one side or the other or just put aside when cooking.
During hot humid times we defrost the evaporator plates every 3-4 weeks as needed, rarely more than 6 weeks even in cooler drier wx. This helps efficiency a great deal (Turn off units for 4-8 hrs depending allowing for ice to lose adhesion and be quickly scraped off. Items do not unfreeze if stored in bags and covered by blankets.) When defrosting all insulation mentioned comes out but rarely needs any attention and mold etc. has not been a problem.
We also added more insulation (spray in expanding foam) from the outside, in part to deal with mold that occurred on the settee cushions near the freezer, but that is another story.
I considered adding more permanent inside insulation such as being discussed but rejected all ideas I came up with as not being any better than what I had or not being easily removable for cleaning. The ABS plastic reported sounds promising, but I would still worry about moisture migration behind and around fixed panels providing a playground for mold, dirt, meat/chicken juice spills etc over the years.
The above insulation made an enormous difference when we were in warm water/hot climate. My memory is that freezer duty went from 60-70% down to 40-45% or better (in tropics water). It was hard to tell as the above evolved over a couple of years. In these cold waters I am in now freezer duty is about 25% .
My best to all, Dick Stevenson, s/v Alchemy, V42-128