Constructing New Fridge / Freezer Boxes

[Tspringer]

I am deep into the process of completely rebuilding my refrigeration and freezer systems. I removed the old boxes... yanked out everything and am now looking at a giant hole in the galley and the bare inner hull sides. Yipeeee!

I have built the basic outer boxes for both the new fridge and freezer using Rmax R-Matte Plus-3 rigid foam board. This is Polyisocyanurate rigid foam board with a reflective outer coating. I bought it at Lowes. It is 3/4 inch thick and says it has a R-factor of 5. This stuff was good to use in fabricating the boxes to fit the space as it is easy to work with.

I have the boxes done and put together using aluminum foil tape. I am now going around all of the inner box seams with Loctite "Power Grab" foamboard construction adhesive. This should fill all the seams and gaps and glue it all together making it plenty strong. I am also going to use spray adhesive to glue on 2 layers of aluminum foil to all outer box surfaces to act as both a moisture barrier and reflective coating.

At this stage... I have my boxes and they are 3/4 thick foam all around. The plan is to measure and order VIP vacuum insulation panels that will glue to all the flat surfaces inside the box. Then, I will measure all inner surfaces again and cut 3/4 inch foam board (same I have used so far) to glue in on top of the VIP panels. So the VIP panels will be sandwiched between two pieces of 3/4 foam board. Finally, the entire inner box will get a solid fiberglass board glued in and all seams will be glassed so there is a solid/rigid surface inside the entire box.

Questions....

IS this board wrong to use? What is wrong with my plan? What kind of adhesive should I use to glue in the VIP panels?

Where can I source the VIP panels and VIP hatches? I would love to have Glacier Bay stuff... but its way out of my budget. I have looked at the Rparts stuff... but with Rparts you get zero support and cannot ask any questions. There is no human to speak with at all. I cannot even find out the diminsions for mounting a hatch before it arrives if I order it. The complete lack of support worries me.

Other than Rparts or Glacier Bay.... what sources are there? It seems I get either cheap but no support at all or very expensive.

I am planning on going with dual Frigoboat keel-cooled compressors with evaporator plates. I need to get this stuff ordered... but I honestly have no idea who to order from? Any recommendations on a good supplier who will take the time to answer questions and help me size the units I need?

Any and all tips are greatly appreciated.

I am shooting lots of pictures and will post detailed step by step info on how this project went when done!



Terry

[motion30]

I was interested in products from rparts but the total lack of comuncation turned me off to them, what is one to do if there is a problem?

[GordMay]

VIPs aren't going to be cheap, no matter where you buy them.
I look forward to seeing your photo-essay, when you're done.

I don’t know any of these companies, but they do sell Vacuum Insulation Panels:

AcuTemp (Dayton, Ohio) ➥ AcuTemp | High Performance Insulation

NanoPore (Albuquerque, NM) ➥ NanoPore Incorporated

Passivehouse Solutions Ltd. (UK) ➥ Vacuum Insulation - Home

va-Q-tec AG (Germany) ➥ va-Q-tec :: vacuum insulation [vacuum insulation panel]

Xiamen Goot (China) ➥ ÏÃßßÌظßвÄÁÏÓÐÏÞ¹«Ë¾
Vacuum Insulation Panels (VIP) Manufacturer exporting direct from Fujian China

Hanita Coatings has some good information on metallic barrier layers, for use /w VIPs ➥ Vacuum insulation panel metallized films and laminates

[Kefaa]

You have me wondering. If you placed a vapor barrier against the hull, would you (anyone), get better R-value using spray foam? Foam It Green Polyurethane Spray Foam Kits - Spray Foam Kits or some similar product? Place the box, then fill the surround area with foam.

[Eleven]

From previous posts I read that 3 inches of foam makes a difference to power consumed. 3/4 sounds slender even if it is good. Top entry is also a big saver.
Domestic units are built to last maybe ten years and by then the foam is degrading etc etc. I'd consider optimising thickness at 2 inches minimum with overlapping 1 joints inch panels and squirty foam to sela it all. Avoid thin spots if possible.
The lid neeeds to an effective insulator too. Volume depends on cruising leg durations.

[s/v Jedi]

Terry,

I have been where you are now, taking 3 months to build three new boxes in 2005. This is what I discovered and how I did it:

First, reset your brain, purge all your current thoughts about the project, just while reading the rest of this post. After that, compare and make your decision.

My first discovery was that vacuum panels were not going to happen. Even the Rparts panels (which are way cheaper) were still outrageously expensive. I could afford it but realized I was not crazy enough to spend that much money on this. VIP's were quoted at $7,800.- to get the idea.

So, what I want to say is that it is much better to have a smaller box with more insulation than the other way around. If you plan to sail into the tropics and not run a genset hours each day, design a fridge with 4" foam and a freezer with 6". A 6 cubic feet box with a BD50 compressor unit will run about 20 minutes each hour, a duty cycle of 1:3. This is for both freezer and fridge because the freezer has more insulation and is opened less.

Start with the selection of foam. Use pure refrigeration foam, 2" and/or 4" thick, no reflective coatings or plastic lining or whatever, because you are going to have several layers and you don't want anything in there that conducts heat better than the foam. Use expanding spray-foam as the adhesive.

Now, you have to make a rectangular outer box where you can put the foam in. When the space for the box isn't rectangular at all, like against the hull, use 1/8" plywood, some 1"x1" battens and a tacker to create the biggest possible rectangular box. You will remove it later, so nothing fancy. Use the 1"x1" battens for the corners but also for plenty supports/struts inside the box to keep it in shape. So, give the box a bottom but no top.

Next, use spray glue to put plastic foil on the outside of this wooden box, except the bottom of course (can't reach it). Use epoxy and roller and brush to coat the inside of the space around the box (like the side of the hull, inside of front-cabinet wall, etc.) Let the epoxy gel to the "very sticky" phase and use it at that moment as the adhesive for aliminium foil, which you put in with the shiny side out (shiny side facing the hull). The epoxy and foil are the moisture barrier and the radiation barrier.

Next, measure one outside of the box (largest measurement) and cut a piece of foam. Parts, like the bottom edge, will need to be tapered. This is easy, use a bread knife and a surform rasp. You can get it to fit pretty quick and every panel will be faster. Spray some expanding foam on the bottom edge (or just into the space down there) and put the panel in. Use masking tape at the top to hold it against the plywood. Keep going on until all is filled up. After that, remove the plywood and plastic foil.

You are now left with a big hole where the bottom should be. You can use sheet-foam or pour 2-component liquid expanding foam (but go slow, 1 mixed cup at a time). Use the surform rasp (after fully cured) to shape it when pouring went a bit out of hand.

Now is the time to decide on minimum isolation thickness and interior volume. I would advise a maximum of 6 cubic feet interior. You make it smaller by putting in more panels on the sides and bottom.

Next is the lining. Easy but time consuming when you want it to look pretty. Start with a sheet (or half sheet, do the math and jigsaw puzzle on paper first) of 3/8" marine plywood. Put it on a level bench or A-frames. Using a black permanent (thin point) marker, draw out all the panels you need for the inner lining. Make the bottom piece the full size so that the walls stand on the bottom.
Don't use the existing edges of the sheet (stay a half inch away from them) anddon't cut yet! Vacuum it.

Drape the lightest fiberglass cloth over the whole panel (in 1 piece) and cut it so that a couple of inches hang over the sides, like a table-cloth. Now start mixing batches of epoxy resin + fast hardener. Pour the first batch (6 pumps if using West System is a good start) in the center of the sheet and use a plastic spreader to spread it. It must become completely transparent without trapped air. This is really easy. Works all the way to the edges and ignore the overhang. Let cure until gelled (still sticky) and add another coat. If the spreader becomes difficult to use, switch to a roller. Continue this process (start in the morning) until the cloth is completely under the epoxy. Let cure for 24 hours; it'll look like a varnished panel and the cloth is only visible at the overhangs.

Cut away the overhang with a sharp knife and smooth it with very course sandpaper (don't cut yourself on the edges, very sharp). Turn the panel over. Use brush and roller to coat the backside and edges with epoxy (fast hardener again). Let fully cure. Dry-sand (wood fibers come up after first layer of epoxy) and coat again. Let fully cure.

Turn panel over again and wet sand it (with orbital sander). Hose it wet and sand; rinse with hose and look how the water flows over the panel: look for any "rapids". This is where you must sand more. Stop sanding when you hit the fiberglass. This is where you decide how pretty the end result must be. You can roll on more layers of epoxy or decide it's good enough.

About the wet sanding: only use the machine when the hose is away and excess water is off the panel. Use a double-insulated sander, which is every modern one I think (label on sander states that with 2 square symbols, one inside the other).

Now you cut the panels. The lines drawn on the wood are as clear as before the epoxy and glass went on.

Put the panels in the box, using very little spray foam (just couple of dots) to hold them in place and immediately put some struts in to force the walls onto the foam. Don't put the top on yet. Use angle to check it is as straight as you want and don't worry about some small openings where they meet. Use thickened epoxy to put fillets in. I used Coloidal Silica to peanutbutter consistency and those West System fillable caulking tubes for a quick job.
Now you have the best excuse in the world for buying the Fein Multimaster tool. You can get sanding attachments to sand the fillets to perfection. Alternatively, use a short piece of hose with sandpaper around it but I ended up with RSI from that job.

Sand everything incl. the underside of the top. Now you can paint it, the top still off the box. I used Awlgrip which is safe (but still not food grade may be) after cure. Don't use white paint with lead.

Now, drill the holes for freon lines. The connectors of the evaporator determine the size. Mine just fit through a 1-1/4" thin-wall PVC pipe. Use PVC pipe, it's the moisture barrier at the most important spot because the freon lines will create condensation. I used a 10" long 1/4" drill bit to drill a pilot hole through the whole lot first. Next was the hole-saw from both sides. I used the PVC pipe itself to cut away the foam. Make the pipe 1/4" too long so that each end stick out 1/8". Use silicone sealant to close the gap around the pipe... do this good, absolutely watertight.

Install evaporator, sensors etc. as the top is still off so easy access. I installed compressors and everything at this phase and tested the system to be sure all the equipment was good. Afterthat, I used silicone sealant to put the top on (don't use stronger, silicone is tough enough and leaves hope to get it off later, if ever needed).

Now, you hopefully didn't forget room for the insulation at the top I hope. Put the sheets on, level the surface with batten and surform rasp. Now, stab the bread knife in what you think is the center of the opening and start cutting to a side. Cut the opening out. Epoxy brush/roller the foam and aluminium again. Should look like a spacecraft part now. Fit collar, lid and counter top, ready!

Some detail photo's attached.

cheers,
Nick.

[James S]

Nice job on the boxes Nick and excellent instructions.

[Marinheiro]

Nick, just curious - what prompted you to rebuild your refrigeration installation? I thought Steve Dashew was pretty particular about this. But then I note Raven is advertised as having had a full system rebuild as well

[hellosailor]

Why not buikd from the inside out? i.e., take off the countertop, or the front. Then start with your box "liner", which woulc be a premade plastic bin or other box that's presealed with no joints. Add layer after layer of insulation to the outside of that, until it just barely can be fit in place. Spray high-expanding foam into the outer parts of the cavity, drop the insulated box back in...and you're at the same place, but I'd expect the build time ot be faster since you are working around a male "plug" with the inner box being first instead of last.

No?

[Tspringer]

Wow Nick.... Thanks for all the info.

I am not giving up on VIPs just yet. Rparts no longer has them, their supplier is out of service for now.

I am working on getting pricing from the other supplier and will post updates when I learn anything.

Terry

[s/v Jedi]

Marinheiro: The foam insulation was completely soaked with condensation off the freon lines. That's why I put the detail on the PVC pipe liner around the hole. I forgot to mention that after all is done, I used expanding spray foam inside the pipe to seal everything.

Also, the whole system was a pain. The Glacier Bay system we had may have been the best in '93 but it's a joke compared to today's Danfoss based systems. Danfoss has won that battle. Steve Dashew recognized that too and he is using the same Frigoboat system as we have today.

HelloSailor: Many people make the inner liner too light. Things get dropped in there (like 8 lb frozen beef tenderloins etc) and there are big temperature swings like when defrosting the box with a heat gun etc. 1/4" plywood or plastic isn't going to stand up to that. Friends on their new Trintella 47 had cracks in the box lining already. That's why I advase on 3/8" ply with 1 layer of glass minimum. We used 1/2" ply. Making that inner lining might look as a big job but it really isn't. The epoxy fillets is the only thing where experience really helps, but these were the first ones I ever did (hence the need for lots of sanding ;-)

But that doesn't mean you can't build from the inside out. My system does that too, but uses a discarded mockup box instead. The advantage of my system is that you don't have to try the box (and take it out after that) every time when you work on the bottom insulation. Plus, it's an easy start and you can use the 4" thick foam panels without much planning if it'll fit.

Terry: The price I posted was for the Glacier Bay panels for 3 boxes of avg. 5.5 cubic feet. So that's $2,600.- for one box. I didn't spend that much on a box including the Frigoboat system! I estimate I spend $4,000.- for three boxes each with their own Frigiboat K50F unit and keel cooler. The digital thermostat and very high R-value allow me to use any box as fridge or freezer.

I have another interresting observation: I started with reading that Calder book on refrigeration and doing some math. I was very surprised the math actually worked out, this is what I did: the 3rd box is under the second. They both have front opening doors and 4-7" foam insulation. This used to be one big box (14 cubic feet!!). The seperation between the two that I put in is a 2" foam panel sandwiched between 1/2" plywood/fiberglass panels. The top box is our regular fridge and we keep it at 5 degrees Celcius (regular fridge temperature). The spill-over created by using only 2" of foam in between, makes the lower box keep a steady temperature of 12-14 deg. Celcius without ever running it's compressor. This is in the tropics, let's say 28 degrees temperature inside the boat. This makes it a very nice box to keep all sorts of things without running it's compressor.

cheers,
Nick.

[Tspringer]

For the record AcuTemp is not a supplier for this kind of application unless your looking for a giant box or many boxes. They have a minimum order of $5,000, no exceptions. If your going to have to spend that kind of money.... may as well go Glacier Bay.

Rparts has no vacuum panels available due to a manufacturing problem, Acutemp wont sell to me.... Glacier Bay is out of my price range. I may be out of options.


Terry

[bobfnbw]

Originally Posted by s/v Jedi

Terry,

Start with the selection of foam. Use pure refrigeration foam, 2" and/or 4" thick, no reflective coatings or plastic lining or whatever, because you are going to have several layers and you don't want anything in there that conducts heat better than the foam. Use expanding spray-foam as the adhesive.
Nick.

Nick nice work.

I don't understand though what pure refrigeration foam is.
When I look online, the best foam seems to be polyisocurate foam.
Like the sheets made by dow tuffr for home building. Its R6 per inch. It is made by others as well, comes with a foil lining for reflecting radiant heat.

wouldn't it be better to use multiple layers of 1" foam, rather than one thick layer, since its air that insulates. Just like layering in cold weather.

I to wanted to try the vac panels, but at the cost... perhaps I will use them on the top only. Cost will be better.

It is hard to get good quality foam, and pretty expensive as well.
But home depot sells a 3/4" isocurate foam for ~13 bucks per 4'x8' sheet, and so will need 6 layers for the fridge and 8 for the freezer.
bob

[Cheechako]

I put the vacuum sealed panels in one boat with a small fridge box. Literally saw no difference in fridge temp or power required. Not worth it!

[s/v Jedi]

Originally Posted by bobfnbw

Nick nice work.

I don't understand though what pure refrigeration foam is.
When I look online, the best foam seems to be polyisocurate foam.
Like the sheets made by dow tuffr for home building. Its R6 per inch. It is made by others as well, comes with a foil lining for reflecting radiant heat.

wouldn't it be better to use multiple layers of 1" foam, rather than one thick layer, since its air that insulates. Just like layering in cold weather.

I to wanted to try the vac panels, but at the cost... perhaps I will use them on the top only. Cost will be better.

It is hard to get good quality foam, and pretty expensive as well.
But home depot sells a 3/4" isocurate foam for ~13 bucks per 4'x8' sheet, and so will need 6 layers for the fridge and 8 for the freezer.
bob

Well, as I wrote, the foam should NOT have anything else than foam so that includes a foil layer. You could only use that for the most outer layer, with the foil facing outwards. If you do use foam with foil and layer it, you create heat-conductive channels and you really don't want that.

The foil is a moisture barrier BTW, unless it's like aluminium foil. The best moisture barrier is a coating of epoxy and it's easy to do either on the inside of the outer frame (wood, hull etc.) or on the foam itself. I used West System with some light density fairing filler and used roller and brush to put it on. The filler helps build up a decent coat in one go without it running down, plus it gives some color so you can see if it's everywhere.

Multiple layers are not better. Best is to use sheet-foam as thick as possible. The only concern is leakage around the edges of a thick panel, that's why you should make the panels a bit small and use expanding foam (spray can) to close (and glue) that gap. Air is the insulator used in foam. Air is only a good insulator when it doesn't move. If you have any voids in the insulation, like between layers, you get convection and air is a very good heat conductor that way (think the heater in your car!!!). The air inside the foam can't move.

Yes, I know the good foam is expensive. But it doesn't matter because it's cheap compared to the time and effort that goes into building a good box. And you want it to last.

In the US, your best choice will be Dow Chemical Styrofoam. These are blue rigid foam sheets. If you scrape it with your finger nail, you shape the foam already. It has no foil and is available in at least 1", 2" and 4" thickness because I used all those. A 4" sheet will cost a couple hundred I think.

You can also contact commercial refrigeration companies, like the ones that service supermarkets etc. I bought the foam from Budget Marine in Trinidad.

The exact same foam is also available is a beige color (it's in view on my photo's too). I think it's made by DuPont.

Don't use vacuum panels for the top !!!! the top has the least heat-load of all. This is because cold air is heavier (more dense) than warm air. So the bottom needs the best insulation and the top can be less R value.

ciao!
Nick.