Aspen Aerogel as insulating medium in a completely new freezer/reefer box?

[skipgundlach]

From a different thread about amphour usage...

Originally Posted by typhoon

I just bought some . Main source for this stuff is eBay . R10 per inch!

I built my own box from 2 and 4 inch 4x8 blocks of extruded polystyrene (styrofoam and other names), hydrophobic and rigid, but I encapsulated it in epoxy, anyway, for more vapor barrier than moisture, and stairstepped the joints for air migration mitigation in the eventual-6-inch exterior.

This stuff looks very interesting, but I wonder how one would fabricate an actual box using it, given that it's totally flexible. My box exterior and interior divider was essentially (variations but not significant) plywood, and I applied the insulation inward, using epoxy to adhere to the doorskin furring strips (conduction barrier) which had been epoxied over the shiny-side-out aluminum foil (radiation barrier), and then further epoxied the interior before beefing up with fiberglass.

And, I wonder if this has any issues like the vacuum panels do, which is that the vacuum eventually dies, and you're left with no insulation (extruded polystyrene does, too, but at a somewhat lesser rate, but a great deal more bulk).

If you were starting from a bare exterior, how would you build your box so that it could have shelves, a freezer/reefer divider/spillover, and doors, using Aerogel only as the insulating medium?

L8R

Skip

[antoha]

You can sandwich it between outer shell (plywood) and inner shell (thinner plywood). The material itself is what has R10, so there's no bubble that keeps smth from happening to puncture (like with vacuum panels). It's also hydrophobic. You're still better off encapsulating everything in fiberglass/epoxy/gelcoat/heat barrier, of course. Also, while it is soft (like felt), it's not very compressible, so even if you don't have plywood enforcement for the fridge floor, it's not going to give much.

As to shelves etc - you need some kind of load bearing frame, much like if you were using a different insulation - you wouldn't screw shelf brackets into pink/blue board directly, right?

[roverhi]

From what I understand, styrofoam soaks up water over time and becomes a poor insulator.

My plans are to wrap the FRP ice box with the AeroGel sheets then encase the insulated box in fiberglass or plastic panels like the ones used for shower surrounds to seal/protect the Aerogel. Aerogel is hydrophobic so is not supposed to absorb water so keeping the material dry is not as much of a necessity as foam or other insulations. Haven't done any of this yet so how it all actually works will have to wait for me to finish it.

All shelving will be screwed into the FRP ice box inner liner with wood cleats and plywood backing.

[skipgundlach]

Originally Posted by roverhi

From what I understand, styrofoam soaks up water over time and becomes a poor insulator.


clip...

Extruded polystryene doesn't absorb water. However, it does, eventually, outgas, reducing the amount of non-solids; it's that which gives it its finite life span.

As to mounting stuff, I built a fiberglass box inside the insulation; it's that to which we screwed our shelf stanchions in the reefer; the freezer is screwed to the plywood skin over the spillover barrier.

I'm definitely not ready to destroy my current box, and this stuff is frightfully expensive. But I guess I could see laying up fiberglass to make panels (this stuff comes in rolls, so it's very floppy), assuming this stuff is epoxy or vinylester tolerant, and then doing approximately the same thing as I did before.

But those who come now, looking to build a new box, might enjoy something more elegant than what I've just described...

[Jim Cate]

Weyalan ran a long thread when he built an Aerogel insulated box for his boat. Try a search...

Jim

[skipgundlach]

Originally Posted by Jim Cate

Weyalan ran a long thread when he built an Aerogel insulated box for his boat. Try a search...

Jim

Thanks. I found the thread.

It looks like this stuff is a bit problematic to try to build with.

One poster identified that the differential in cost to achieve R30 aerogel and R35 polyisocyanurate (more expensive than what I have, but also slightly more efficient insulation, assuming it never sees any water) is ~1500 for his box.

That is ~$45/sf for aerogel and $10/sf for polyiso.

I don't recall what my insulation worked out to, but it's 6" and a stout box. I used Foamular (Owens Corning - pink panther); 2 and 4 inch are 10 and 20 respectively, so my fabrication is R30...

So, while there are a few little things I'd do differently if I have to rebuild in my lifetime, due to outgassing, I believe I'd use the same stuff.

L8R

Skip

[Bulawayo]

The last box I built was constructed from the inside first to the outside. That way it was very simple to build and ensure decent overlaps. I used epoxy soaked marine ply as the core making attachment of the holding plate very simple.

[SV DestinyAscen]

If you're looking at aerogel, I'd also suggest looking into insulated vacuum panels. They're both cost prohibitive, but a box is one of the perfect applications for the panels (no concern for puncture/nicely paneled, light, stable).

[reed1v]

The gel needs to be applied so it stays expanded. Compressed its worthless. You get about the same r value by using layers: one with a vacuum, one with a non heat absorbing quality(asbestos) , one with a radiant reflective side, and one that protects the other three layers. Now double this so you have a two inch wide composition. Make a box out of that and you have a very well insulated box.

[Captndave1]

I just finished reinsulating my box, but from the inside. Removing the actual refer box was totally impossible without tearing out half the galley. I laid a layer of Aspen Aerogel around the inside of the box using spray contact cement then glued in a finish of the bathroom panel material. Then i sealed all the corners with a special 4' wide, strong adhesive, white vinyl tape. Then installed a new Vitra Frigo refer system. Now my compressor only runs about a total of an hour a day. Fantastic as far as I am concerned.