Reefer insulation

[phlbob7]

My reefer box was built by a company in Bellingham, Washington. The insulation is very poor and my 12volt compressor is running way to much The freezer door was rebuilt at Baja Naval in Ensenada, Mexico. They did a wonderful job. In a cabinet behind the freezer compartment, I was pulling some stored items out. The condensation is so bad that it ruined a big box of tea and a bunch of movies. The wall/bulkhead is soaking wet but only by the freezer. That is how I know the insulation they used was no good. What is the best type of insulation to use? I realize all the old will have to be pulled out. phlbob7@ yahoo.com

[skipmac]

There are several options for new insulation. None of them are the liquid, pour in or spray in stuff.

There's some new stuff whose name I forget (Aerogel or something like that) but I was never clear on handling and installation. Several forum members have used it and swear it's the greatest thing since sliced bread. However I have also heard it makes a lot of dust that is very unhealthy.

I went with the tried and true Dow Blue Board which is polystyrene (a fancy version of the plain old Styrofoam). I have 4" most places 6" along the hull and 3" in a small area on the side where I was out of room. Extremely happy with the results. I have a box total 9-10 cu ft including a 1.5 cu ft freezer box and was using about 50 amp hours/day in August in Florida.

[roverhi]

Believe the rule of thumb is 4" blue board for the refrigerator section and 6" for the freezer.

Will probably be using this stuff to cut down on space eaten by blue board.
Aerogel | Aerogel Insulation | Aerogel Price

[lovinlifebda]

Used the Dow Blue Board as well when I rebuilt the fridge/freezer and am very happy with the results. Read everything you can find from Richard Kollman before you do anything else.

[antoha]

you can also use aerogel. twice the R number of the blue stuff, and it is hydrophobic. there's a seller on ebay, with a decent price. comes in a 1cm ~ 1/2" thick sheet (looks like a felt blanket). have to be careful when working with it - look up the safety sheet, it gives up fine talc like powder.

i went through one of the manufacturers, bought cutoffs [scraps] at half price, but wouldn't do it if i were doing it again: these 5-8" wide strips are more of a pain than it's worth, much easier to deal with sheets that you can actually cut to the size you want.

i also don't have a performance estimate: we're not liveaboards, and what i replaced was an icebox with 45 year old 1/2"-1" thick insulation which was melting ice faster than you could buy it. all i can say for now is that in 75-80F (NYC temperatures currently) the fridge (seafrost) performs as expected by the manufacturer. (i removed the old icebox and build a new one in its place from scratch, for which i had to dismantle the whole galley area, remove the cabinetry, etc. all in all about 400 hours of my [non professional] labor, i probably wouldn't do it again.)

[antoha]

roverhi - incidentally, this is the manufacturer i bought from directly. very nice folks to deal with (but again: now i'd pay full price instead of buying for scrap/leftover material; penny pinching is foolish with this scale of a project).

[skipmac]

Originally Posted by antoha

you can also use aerogel. twice the R number of the blue stuff, and it is hydrophobic. there's a seller on ebay, with a decent price. comes in a 1cm ~ 1/2" thick sheet (looks like a felt blanket). have to be careful when working with it - look up the safety sheet, it gives up fine talc like powder.

So how do you work with this stuff? If it's like a felt blanket won't it compress? Does it lose insulating value if you compress it? How do you build up multiple layers, can you glue?

Originally Posted by antoha

i removed the old icebox and build a new one in its place from scratch, for which i had to dismantle the whole galley area, remove the cabinetry, etc. all in all about 400 hours of my [non professional] labor, i probably wouldn't do it again.)

I did exactly the same thing and put at least 400 hours into the job. It came out great, the galley looks the same as it did before I ripped out the cabinet work but what a job. It was by far the biggest single project in my refit and I sure hope I never have to do it again.

But the new fridge works great!

[s/v Jedi]

Check out this photo-series for a similar project to replace and add insulation:

Refrigeration - sv-Jedi

[skipmac]

Originally Posted by s/v Jedi

Check out this photo-series for a similar project to replace and add insulation:

Refrigeration - sv-Jedi

Excellent resource. Before I built my fridge I stole some ideas picked up some helpful hints from your write up.

[antoha]

It doesn't compress much but I didn't take chances: used a frame with kind of staggered wooden rests so there's no direct "run" of just wood.


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[Warby12]

"None of them are the liquid, pour in or spray in stuff."

Hi Skipmac, I did an icebox in Aus with the mix and pour stuff and it was terrific, maybe the quality varies. One bag of ice, in the tropics, would last a week. Just sayin'

I agree though, easier ways to do it as you have to pour carefully to prevent excess pressure, toxic fumes etc, sorta fun though.

[skipmac]

Originally Posted by Warby12

"None of them are the liquid, pour in or spray in stuff."

Hi Skipmac, I did an icebox in Aus with the mix and pour stuff and it was terrific, maybe the quality varies. One bag of ice, in the tropics, would last a week. Just sayin'

I agree though, easier ways to do it as you have to pour carefully to prevent excess pressure, toxic fumes etc, sorta fun though.

Hi Warby,

The main reasons I recommended against the pour in insulation are first, the "experts" say over time it will absorb moisture. I have to say that when I ripped out my old fridge which had a (very, very thin) layer of poured on foam it was bone dry in a 30 year old boat. But I never, ever want to redo my fridge so did not want to risk it.

The other issue is the proper handling. Like you say, toxic fumes and, if you pour in just a little too much it can split your cabinets apart. Amazing how much pressure that stuff can generate and yes it is fun and probably would have been a lot less work than cutting and fitting all the foam boards I had to do.

So, how long have you had your box working? Any evidence of losing efficiency?

[antoha]

Skipmac: you can't glue it. Nothing I tried works on aerogel - it just flakes off. So I built an outer shell (thin marine ply soaked in epoxy on both sides + 1 layer of glass on the outside), then small wooden struts (bottom only) and insulation (as many layers as you desire, use scissors to cut to size, and cut out spaces for the struts to fit into) then another thin layer of marine ply soaked (again, bottom only), then more wooden struts a little offset (so these support struts do not span the entire thickness of insulation in one stretch), the rest of insulation, then 1/2" marine ply, soaked, then several layers of glass. Side walls were just fiberglass, no struts and no ply (but still outer shell first). I tried to do it in one go but that was a mistake: you can only effectively lay glass down, not on a vertical surfaces or even worse upside down. So best to work on one surface at a time, so you're always laying the many layers of blanket first, and then glass right on top of it.

I have a total of 8-9 layers of 1cm sheets, equiv to 6-7" of blue board insulation. My constraint was that if I were to use regular insulation, I'd end up with half the usable volume I have now.

I also rebuilt the lid - replacing insulation inside, and adding another "pillow" of insulation outside.



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[skipmac]

Hi Antoha,

From your description it sounds like the Aerogel was a good bit more difficult to use than the blue board. It would have made my final fit of the inner box into the galley cabinet easier if I could have had a compressible layer allowing looser specs on the width of the box . Doesn't sound like the Aerogel would have worked for that either since I would have had to attach it to the blue board in some way before sliding the box into the cabinet.

In my case I had plenty of room and actually wanted to reduce the box size a bit. The original if I recall was over 12 cu ft. The rebuilt box is about 9 which I think is fine.

I also used an epoxy coat but only on the inside of the cabinet work. I also attached a heat reflective layer of Al foil to the epoxy before starting the layers of foam.

Box and cabinet top are all done. Just have to finish insulating the lid, the last step.

[antoha]

Skipmac: I started at ~7 cu ft, now I have 5, would have had 3. In your situation I would have done what you did.

If I were building "in place" (instead of what I did, which was to do all the work outside the boat, and then place the finished product into the boat), I would have needed to build the vertical walls separately and then tab them in. Or, use a 1/2" final layer of blue board on top of whatever layers of aerogel.

But I agree: if space was not such an issue for me, using aerogel wouldn't have made much sense.

On the other hand, now I kind of know how to lay fiberglass...


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