Aerogel - Spaceloft Insulation for Fridge / Freezer

[YachtManuals]

We have just rebuilt our fridge with Cryogel. Be aware that the R value of 10 is for 1" (not for one layer), so it's about twice that of rigid foam. I was sent a sample that was 8mm thick (old sample). The new roll was about 11mm thick , but it compressed easily to 10mm.

As it's not easy to measure the final R value of the fridge, I cannot give numbers other than:

fridge box size: 2.8 ft3 (top lid)
10mm Cryogel layers: 4 (5 on bottom and behind evaporator plate)
box temp: 34-36F
new compressor: isotherm aircooled with BD35 compressor
power consumption (in winter with 60-70F in cabin): 17 Ah/day (13V)

This is a huge improvement over our original 23 year old fridge (4" foam and a Supercool Peltier cooler).

Any fridge box needs to have very good vapour barrier on outside (from moisture in air) and inside (from a wet floor). We poured 1/8" white self-levelling epoxy inside on the floor, over the FRP smoth board. The outermost layer of insulation needs to be perfectly sealed, usually with alu-foil/mylar. The Cryogel foil can be sealed at the edges with good alu tape. Or make the fridge outer compartment totally vapor proof (including the freon pipe and wire passages).

Make sure to remove the the Cryogel foil near the edges of your inside layers to avoid thermal bridges. Keeping the Cryogel foil on the center of each layer helps to handle this rather unpleasant stuff, as you glue layer upon layer.

Cutting Cryogel: large scissor, or a sharp box cutter with a very fast movement, against a cardboard of wooden floor (the fibers tend to want to snag and bunch up on the blade).

I was never able to get an answer from Aspen Aerogel (phone or email) so I never found out if Cryogel, Pyrogel and Spaceloft use the same basic insulation (other than the surface foil). They are rated for very different temperatures but that might depend more on the backing foil than the actual material. It certainly looks like the only thing that makes Cryogel hydrophobic is it's foil backing, and that could be added to spaceloft on the outer layer.

[senormechanico]

Trust me, the Aerogel doesn't need the foil to be hydrophobic.
When I cleaned up my garage floor after construction, I swept and swept.
There was still a fine layer of the powdery residue, so I got out the garden hose.
IMMEDIATELY, there were fine balls of white stuff which turned out to be balls of water covered in Aerogel ! Really weird looking.
I had to basically pressure wash the floor with the hose turned to a fine stream to knock the stuff out of the pores of the smooth concrete.
Outside the garage, the powder separated itself in little lines from the water.
I'm convinced the hydrophobic properties are in the Aerogel itself.

[Celestialsailor]

I was the one that, in error, claimed the R-30 number for 3 layers. I apologize and am paying for the mis-information I received. After I am finished, I will be able to attain R-20+ with the Aerogel I used, backed up with Isocyanate pour foam....There...my force feeding of humble pie!

[Cotemar]

Cryogel is Hydrophobic
Pyrogel is Hydrophobic
Spaceloft is Hydrophobic

ASPEN AEROGELS | PRODUCTS OVERVIEW
Hydrophobic Aerogels are specially formulated to repel water and to not absorb moisture from the air. Where Classic Silica tends to shrink and cloud in humid environments, Hydrophobic Silica retains its transparency and integrity. Floats on water without damage!

You can make a super refrigeration or freezer shell with this insulation. It is Hydrophobic, which means it will not absorb water so, moisture from condensation is not a problem.

Although by volume it is 99% air. It is breathable, but it doesn't absorb water. It is incredibly strong for its weight. But most importantly, it is a fantastic insulator.

Superhydrophobic aerogel mat in water - YouTube

[ventured]

I insulated with two layers of Aerogel Cryogel with backing foil, and a layer of Home Depot pink board. Based on a limited time frame I just filled the inside of my existing box, rather than tear it all apart and start over.

We are in Mexico now, and while I haven't done any scientific studies on it, I'm keeping up with all my electrical needs with two 190 watt solar panels and a Blue Seas MPPT controller, and a 440 amp batter bank. I just spent a month on the hook without running the engine to charge and rarely see less than 12.5 volts on my battery bank. We are running an air cooled BD 50 compressor on a its lowest setting.

My one word of advice is wear a mask cutting this material, I ended up seeing a doctor for uncontrolled nose bleeds a couple days after cutting all my areogel.

Some pics and a write up: Our Breast Cancer awareness fridge | Ventured

[Kelsea]

where did you get it and what did it cost?

[Cotemar]

You can buy Aerogel - Spaceloft on eBay
$5 per sq. ft.
Aspen Aerogel SPACELOFT Insulation Hydrophobic Mat, Per Square Foot | eBay

[YachtManuals]

I guess I used the wrong word. Hydrophobic means to repel and not absorb water, which it does. While this is good, it's not likely that our fridges will get water on the outside, so it's a moot point.

The real issue is: water condensing from the vapour in the air. The ebay seller wrongly claims that water from condensation is not a problem with spaceloft. Why do you think that only Cryogel has the water barrier foil on it? Because it's the only version made for cold applications: water vapour (a gas) in the air will condense as it slowly circulates into the spaceloft and reaches the dewpoint temperature at a certain depth into the material. As long as the fridge is on, more vapour condenses and piles up inside the insulation. This may happen rather slowly, but since our fridges tend to be on permanently for years, it will add up over the years. The only way to remove it is to heat it, or possibly by using a dehumidifier, unlikely in a cruising boat. Even if the aerogel nanoparticles themselves are hydrophobic, if they are surrounded by water you can be sure there is loss of insulation within the 'blanket'. Ask any real refrigeration professional and they will say that a vapour barrier on the outside is essential. I have removed several old built-in boat fridges and they all had water present within the layers of foam, particularily in the coldest area.

[senormechanico]

That's why it's important to seal not only the outside, but the INSIDE as well.

[Richard Kollmann]

YacthManuals, is correct open cell insulation designed for the building industry will act as a dehumidifier capturing moisture from the air if used as refrigeration insulation in a marine environments. If insulation is not sealed to prevent internal air/gas from moving in and out of it heat conducting moisture will accumulate in it. Efficiency destroying moisture into these open air cells may take a year or more to cause serious problems on a 24/7 live aboard boat. Each time a refrigeration unit cycles OFF and ON internal air expands and contracts. As air contracts it brings in moist air and when it expands air exiting will deposit its moisture in any area where temperature is more the 7 to 9 degrees cooler. I have found spun glass home insulation, much the same as Spaceloft, waited down so much with water it dropped into the bilge. I even recommend in my books that closed cell Polyurethane be encapsulated in builder’s plastic to reduce R value loss as insulation aging out-gassing occurs.

[Paul Lefebvre]

Richard

Did you get a chance to test this material on the sample that was going to be shipped to you from another member? If so, can you let us know what your conclusions were.

Also, do you feel that wrapping this material in builder's plastic would make it suitable for long term cruising in the tropics.

[Coachbolt61]

Hi. Just some questions regarding condensation. If you pack the insulation ( doesn't matter what type) against a cold surface ie fridge or deck, won't somewhere through the insulation be the temperature where condensation would occur? If you have the type of insulation which has the foil against the cool surface, won't that stop the water getting away from the surface? Wouldn't it be better to draw the humid air away from the surfaces to stop rot?
From someone who is also about to go through this process with fridge boxes.
Coachbolt.

[Cotemar]

Coachbolt,

Looks like the Pro Aerogel installers all put the foil out and install multipul layers
They foil tape each layer so nothing gets in or out.
If you are + R30 (+3 inches) that will be 8 layers of .4 thick sheets.
You will not have to worry about condensation.

[Coachbolt61]

Thanks for the reply Cotemar.
Sorry to labour the point but a previous post said that their insulation became waterlogged. Wouldn't there be a point where the water condenses within the insulation? Am i missing something? I have a steel boat hence the concern. I want to be able to remove the insulation off the steel to check for rust. Anything glued would be pain as I am finding out.
Coachbolt.

[YachtManuals]

The moisture originates from ambient air, hence the need to foil the outside (assuming water inside the fridge also does not leak out into the insulation). Water woould accumulate on the coldest part, e.g. the box liner and copper pipes. If the back of a fridge is against a steel hull (and assuming you cannot dismantle or remove the fridge), then the best would be to have a ventilation space between the hull and fridge foil/insulation. The biggest problem with steel hulls or tank tops is water dripping from a cold spot of the system, such as an uninsulated freon copper pipe, or an unsufficiently insulated area of the box (outside of foil). Water drips tend to occur in few areas that can be guessed at, and these spots could be made visible, such as the bottom back edge of the box, looking up from the bilge. You might also be able to put a plastic drip tray or liner on the inside steel hull.