Aerogel - Spaceloft Insulation for Fridge / Freezer

[zboss]

Originally Posted by Weyalan

Sure, but I'm not confident it will help you much. It was "The Perforated & Expanded Metal Company" In Hobart, Tasmania, Australia, lol.

Seriously though, if you do a google search for performated metal in your area, you should be able to get hold of some easy enough. The only problem is whether you will be able to get what you want without having to buy an 8' x 4' sheet, heh

The stuff that we got was aluminium and probably about 50% metal, 50% hole, I guess, maybe 1.2mm (3/64") thick, but pretty much anything will do... we just wanted to try to make sure we protect the expensive and relatively fragile cold plate from accidental contact with heavy or sharp objects.

Mcmaster Carr has a huge selection of perforated sheet metal to choose from.

[morays]

Weyalan,

Thanks for the info. Your proper description of the material has helped me source some over here without issue.

[nhschneider]

I know this thread is pretty old but I've been reading through it with great interest. About 15 years ago, I spent an exorbitant amount of money installing Glacier Bay vacuum panels for my refrigerator and freezer, only to find out they're worthless. The last 5 years of continuous cruising has made us a slave to our genset as our refrigeration compressors run non-stop and our batteries (1,100 amp-hours) need charging twice a day. Even with two massive solar panels, they can't keep up with the demand.

Now that we're in South Africa, we've decided to bite the bullet and correct the mistake I made 15 years ago by tearing out the Glacier Bay vacuum panels and reinsulate the fridge and freezer. From what I've read, the Cryogel Z is the way to go only it's not available in South Africa nor are any distributors willing to ship it here.

My fridge and freezer are made of stainless steel. What if, once they're removed, I build another stainless steel box around the existing fridge and freezer, install a Schrader valve and create a vacuum for insulation? I realize that it probably wouldn't hold a vacuum forever but a vacuum pump isn't that expensive and even if I had to pump it down once a month, do you think I'd have a better insulated fridge and freezer? Is this a perfectly ludicrous idea or a possibility? Of course, there would need to be spacers to maintain a distance between the two boxes and perhaps it would still need some type of insulation material in the vacuum space - these things would be better answered by an engineer.

Any comments would be appreciated.

Fair winds and calm seas.

[Saltyhog]

I like the idea, essentially a stainless steel thermos bottle in the shape of a fridge. But a schraeder valve seals things the wrong way. IE, the vacuum would keep the valve open. But I'm sure there is a proper valve for the application. Also, I think to improve things further, I would install 2 valves so that you could flood the insulation space with argon first, then draw the vacuum down on the argon. You will never pull a perfect vacuum, but since argon is a much better insulator than nitrogen, you'd do better than with air. IE, the remaining argon in the space would be less thermally conductive than if it were air.

[Ukeluthier]

I think your idea would be be very expensive to implement, given the mechanical strength necessary to resist the enormous forces involved.

If you could pull a perfect vacuum (which you can't, of course), every square inch of the enclosure would be subject to a crushing force of 14.7 pounds, over a TON for a single square foot.

Given that the interior of the fridge is at atmospheric pressure, some sort of very strong spacer medium would be necessary between the inner and outer walls of the vacuum chamber. There are resin-impregnated paper honeycomb panels that are incredibly resistant to distributed crushing, but the amount of surface contact and heat conduction in the spacing medium might well counteract any advantages of the vacuum.

"Thermos" bottles work because their convex curved shape naturally resists atmospheric pressure (sort of the "eggshell" effect). Flat sides are much more problematic.

[antoha]

How much space do you have for insulation? If 3" or more, aerogel will work, even without vacuum. Don't know how feasible the vacuum part would be at all - if the cool blue (some of the best systems, I heard), professionally made and installed, didn't work - why do you think your solution will?

Anton


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[Richard Kollmann]

SV Rutea How long did unit operate correctly before and what was climate location when it operated in the beginning? How did you determine that problem is with insulation and not the performance of refrigeration unit? If problem is insulation Your best solution is to consider adding moisture resistant insulation like DOL Blue Board to box’s interior.

Open cell insulation whether inside a Vacuum Insulated Panel or Aerogel, Cyrogel are risky experiments when used in marine refrigeration box insulation. Good advice given 15 years ago when experimenting with boat refrigerated box insulation is still good today; Always design cabinetry so that insulation can easily be replaced when its effective R value is no longer adequate.

What make insulation in a marine refrigeration environment different than other applications for open cell insulation is moisture in air and movement of moist air in and out of open cell insulation. The first statement of the 2nd law of thermodynamics - heat flows spontaneously
from a hot to a cold body. Each time compressor runs moist air moves into cooler open cells, then as cell warm up air expands leaving heat conducting moisture condensation in open cells. The accumulation of moisture each time compressor cycles if not drained away by some means will destroy the heat conductive resistance of each wet cell.

Marine refrigeration insulation failures all seem to be related to the moisture barrier air leaks. Once moisture is trapped in insulation cells which it can be with open cells a vacuum pump that has the ability to remove atmospheric pressure down to less than 200 microns will remove it by dehydration. The other problem is will the surrounding structure support this low if a vacuum.

[socaldmax]

What has steered me away from aerogel is that it readily dissolves in water, rendering it virtually useless afterwards. There is a new product called Airloy that looks like a white plastic sheet. It's machinable, extremely durable (you could use it as the inside liner of the fridge or freezer) and is the same density and nearly the same insulation value as Aerogel.

Here is a video of the 2 compared. Note how delicate and water soluble Aerogel is.

https://www.youtube.com/watch?v=k8OhJKR3AA4

[Saltyhog]

$90 for a piece 2″ x 3″ x 0.3″. A bit pricey for me.

[socaldmax]

Yup, me too!

[nhschneider]

Originally Posted by Richard Kollmann

SV Rutea How long did unit operate correctly before and what was climate location when it operated in the beginning? How did you determine that problem is with insulation and not the performance of refrigeration unit? If problem is insulation Your best solution is to consider adding moisture resistant insulation like DOL Blue Board to box’s interior.

Open cell insulation whether inside a Vacuum Insulated Panel or Aerogel, Cyrogel are risky experiments when used in marine refrigeration box insulation. Good advice given 15 years ago when experimenting with boat refrigerated box insulation is still good today; Always design cabinetry so that insulation can easily be replaced when its effective R value is no longer adequate.

What make insulation in a marine refrigeration environment different than other applications for open cell insulation is moisture in air and movement of moist air in and out of open cell insulation. The first statement of the 2nd law of thermodynamics - heat flows spontaneously
from a hot to a cold body. Each time compressor runs moist air moves into cooler open cells, then as cell warm up air expands leaving heat conducting moisture condensation in open cells. The accumulation of moisture each time compressor cycles if not drained away by some means will destroy the heat conductive resistance of each wet cell.

Marine refrigeration insulation failures all seem to be related to the moisture barrier air leaks. Once moisture is trapped in insulation cells which it can be with open cells a vacuum pump that has the ability to remove atmospheric pressure down to less than 200 microns will remove it by dehydration. The other problem is will the surrounding structure support this low if a vacuum.

Mr. Kollmann-
Thank you so much for taking the time to reply to my post. My wife and I had spent a stratospheric amount of money hoping to both insulate our refrigerator and freezer well but at the same time maximizing the small amount of space in which to keep our cold and frozen food. I complained to the contractor who installed the insulation for me (who, by the way, was a remarkable shipwright and got caught in the middle between Glacier Bay and me) and in turn, he complained directly to Glacier Bay. Apparently, his complaints carried enough weight that the president of Glacier Bay (I've forgotten his name) came to my boat where he blamed everything - holding plates, drains, weather stripping, etc - but refused to acknowledge that his very expensive vacuum panels might be the cause of our problems. It was obvious that filing some sort of legal action would be far more expensive and futile than just walking way from the US$8,000 investment in worthless insulation.

We have had refrigeration technicians in Mexico, New Zealand, Austrailia, Thailand and South Africa look at our system and all of them - some of whom I judged to be very capable craftsmen - said that our two BD80 Danfoss compressors were fine. Regardless, the two compressors draw about 30 amps per hour and while we were in the tropics - about 5 years - they never stopped once.

We've still managed to enjoy our cruising and we're looking forward to more but we've decided that we'll spend the money and sacrifice the space so we can get a properly insulated refrigerator and freezer. If your recommendation is the DOL Blue Board, than that's what we'll install. I just hope it's available in South Africa.

Once again, my many thanks for your assistance.

Fair winds and calm seas.

[Saltyhog]

Originally Posted by nhschneider

Mr. Kollmann-
Thank you so much for taking the time to reply to my post. My wife and I had spent a stratospheric amount of money hoping to both insulate our refrigerator and freezer well but at the same time maximizing the small amount of space in which to keep our cold and frozen food. I complained to the contractor who installed the insulation for me (who, by the way, was a remarkable shipwright and got caught in the middle between Glacier Bay and me) and in turn, he complained directly to Glacier Bay. Apparently, his complaints carried enough weight that the president of Glacier Bay (I've forgotten his name) came to my boat where he blamed everything - holding plates, drains, weather stripping, etc - but refused to acknowledge that his very expensive vacuum panels might be the cause of our problems. It was obvious that filing some sort of legal action would be far more expensive and futile than just walking way from the US$8,000 investment in worthless insulation.

We have had refrigeration technicians in Mexico, New Zealand, Austrailia, Thailand and South Africa look at our system and all of them - some of whom I judged to be very capable craftsmen - said that our two BD80 Danfoss compressors were fine. Regardless, the two compressors draw about 30 amps per hour and while we were in the tropics - about 5 years - they never stopped once.

We've still managed to enjoy our cruising and we're looking forward to more but we've decided that we'll spend the money and sacrifice the space so we can get a properly insulated refrigerator and freezer. If your recommendation is the DOL Blue Board, than that's what we'll install. I just hope it's available in South Africa.

Once again, my many thanks for your assistance.

Fair winds and calm seas.

I'm pretty sure Richard meant to type DOW Blue board. I believe Owens Corning pink board is equivalent. They are available at builder supply stores.

[LakeSuperior]

If there is room, on the cold side of the closed cell insulation slip in 1 to 5 layers of slightly wrinkled bare polished metal foils. Think space blankets. The metal foils will create a powerful radiation barrier and reduce the delta temperature across the closed cell insulation. The wrinkles create a thin air gaps which decouple conduction.

Consider that there is a temperature gradient that starts at room temperature and ends at the temperature of your cold box. You can retard conduction, convection, and radiation anywhere in the gradient to reduce the net heat flow.

[antoha]

I have some aerogel leftover, I'll try to dissolve it in water and see what happens. But I was told by the manufacturer it's hydrophobic. It comes in sheets (1cm and 0.5cm I believe, looks and feels like a felt blanket of sorts), is easy to cut with scissors, and the drawbacks that I can see after working with it are: you can't glue it, and you have to wear protection (gloves and I'd say mask) because it gives off a fine talcum like powder. The manufacturer has the hazard sheet on their site.


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[zboss]

I think you guys are confusing aerogel with spaceloft which is perfectly suitable for insulation (3"= R-30), is hydrophobic, and is as mechanically sturdy as fiberglass batting- which btw also looses r-value when crushed. Certainly a lot more expensive than blue board but if you want to maintain the size of your fridge (we do) its your only real option besides the vacuum panels.