Refrigeration- Making it Better

[Roy M]

The highest efficiency insulation is indisputably vacuum insulated panels. Nanopore is a supplier. Insulation is the key, keep the cold in, the heat out and the compressor cycles fewer times, consuming fewer amp-hours. All the other solutions presented here are variations on a theme of doing the job for the least cost and effort. Get past the cost and the effort to rebuild the interior and you will have the superior system.

[WebWench]

Thanks for all the opinions and ideas...very helpful as we are in the planning stages. We will research all the suggested forms of insulation.
I want the inside to be solid and easily cleanable....nothing worse than mold near food. We already know what does not work....we will not use wood in there and we will not use silicone caulk (it leaked and soaked the wood....big mess and refrig temps started to rise).
The DH is leaning towards something called Cousa (sp?) board and then fiberglassing over it to make the inside of the fridge one solid unit. Thoughts on this?
We know if will be costly and a lot of work...but he wants it done right.

[skipmac]

Originally Posted by Celestialsailor

I'm not sure soft foam is the way to go. You can buy 4X8 sheets of FRP at Home depot. My friend did this and lined the inside of the box with it using 3M 4200 and caulking the seams.

It's the combination that I used. The foam for the R-value and the FRP for sheathing to protect the soft foam.

[WebWench]

How thick is the FRP? Is it strong enough to prevent dents in the insulation behind it?

[skipmac]

Originally Posted by WebWench

How thick is the FRP? Is it strong enough to prevent dents in the insulation behind it?

Have to measure to say exactly but about 1/8". Not super thick but yes, if bonded to a flat sheet of foam without big voids it would certainly prevent dents, at least from anything normal. Now if you drew back and whacked it really hard with a 20 lb sledge hammer it might leave a mark.

I have a piece of the glass bonded to the foam core about 4" X 6" from one of the tests I did that I could send if you want to see how it looks.


Skip

[Rubikoop]

Originally Posted by WebWench

How thick is the FRP? Is it strong enough to prevent dents in the insulation behind it?

.090 if this is what is being discussed. http://m.homedepot.com/p/4-ft-x-8-ft...600/100389836/

[vRUN]

Originally Posted by Roy M

The highest efficiency insulation is indisputably vacuum insulated panels. Nanopore is a supplier. Insulation is the key, keep the cold in, the heat out and the compressor cycles fewer times, consuming fewer amp-hours. All the other solutions presented here are variations on a theme of doing the job for the least cost and effort. Get past the cost and the effort to rebuild the interior and you will have the superior system.

* Building insulation materials in widespread use are polystyrene and polyisocyanurate panels and polyurethane spray foam.
(Cheap: These materials have an R-value of about R-5 to R-6 per inch.)

* Fiberglass batts/blankets , have an R-value of about R-3 per inch.

* Aerogel is an intriguing material which has an R-value of R-10 per inch
(still expensive to produce and, because it is so fragile, difficult to incorporate)

* Vacuum boards can provide as much as R-30 per inch.
(same problem/worse than aerogel, expensive, custom and mostly fragile)

* NanoPore (R=40) is patented and wikipedia'ed but where can I buy ???

* "Glacier Bay" offers "Barrier Ultra-R" panels, which use aerogel inside a sealed, evacuated panel (R-50 per inch, very expensive, custom size)

NEVERTHELESS:
Any engineering solution has to take into account that every fridge isn't a static system. Doors need to be opened, warm goods to be cooled down, heat to be transported away. Even the best isolation will not cover for a very inefficient door seal or <gasp> something like "peltier-cooling"

[skipmac]

Originally Posted by Celestialsailor

I'm not sure soft foam is the way to go. You can buy 4X8 sheets of FRP at Home depot. My friend did this and lined the inside of the box with it using 3M 4200 and caulking the seams.

Sorry, I think I'm confused (too easily done these days).

Certainly for structure, hardness and impact resistance the sheets of FRP, but what do you put behind the FRP for insulation, R-value?

Are we talking about the same FRP sheets? I bought mine at Home Depot, white with one side textured the other smooth, about 1/8" thick. Then I glued the FRP sheets to the blue foam board with the FRP as the exposed surface inside my refer box. So I have the strength and water proof (water resistant?) FRP covering for structure and the foam under for R-value.

So do you know of some other kind FRP sheet that also insulates?

So are we talking apples and grapefruit?

[skipmac]

Originally Posted by vRUN

* Building insulation materials in widespread use are polystyrene and polyisocyanurate panels and polyurethane spray foam.
(Cheap: These materials have an R-value of about R-5 to R-6 per inch.)

* Fiberglass batts/blankets , have an R-value of about R-3 per inch.

* Aerogel is an intriguing material which has an R-value of R-10 per inch
(still expensive to produce and, because it is so fragile, difficult to incorporate)

* Vacuum boards can provide as much as R-30 per inch.
(same problem/worse than aerogel, expensive, custom and mostly fragile)

* NanoPore (R=40) is patented and wikipedia'ed but where can I buy ???

* "Glacier Bay" offers "Barrier Ultra-R" panels, which use aerogel inside a sealed, evacuated panel (R-50 per inch, very expensive, custom size)

NEVERTHELESS:
Any engineering solution has to take into account that every fridge isn't a static system. Doors need to be opened, warm goods to be cooled down, heat to be transported away. Even the best isolation will not cover for a very inefficient door seal or <gasp> something like "peltier-cooling"

Excellent and concise summary of the insulation options including the pros and cons of each. From my research on the subject I came to the exact same conclusions.

One question, I contacted Glacier Bay a couple of years ago when I was doing my research and they told me at that time they were not doing any of the marine or insulation products but focusing exclusively on their products for the trucking industry. I just tried to check their web site and could not connect so wonder if they are still in business?

[skipmac]

Originally Posted by Rubikoop

.090 if this is what is being discussed. 4 ft. x 8 ft. White .090 FRP Wall Board, MFTF12IXA480009600 at The Home Depot - Mobile

I went and checked the label on the sheet in my truck and that is exactly what I used.

So, how tough is it? I just conducted a highly scientific test.

Set a sheet of Dow polystyrene on my patio and set a 10X10" square of the FRP on top. Then dropped a can of beans from 6' so the edge of the can hit the center of the FRP.

The can left a curved crack in the FRP about 2" long and 1/16" deep, cracked all the way through the FRP so it would leak standing water. There was a corresponding mark on the foam but very, very shallow as the foam bounded back and what was left was barely discernible. If I managed to drop a can of beans or some other heavy object and crack or dent the bottom of my fridge, from my experience in the construction of the box I could make an invisible repair with just a few dabs of epoxy and be as good as new.

[Rubikoop]

As cheap as that stuff is do you think the results would be different if you had used 2 layers of FRP?

[skipmac]

Originally Posted by Rubikoop

As cheap as that stuff is do you think the results would be different if you had used 2 layers of FRP?

Probably. Will conduct additional, highly technical, scientific testing with two pieces of FRP.

Also, for the test I just set the FRP on top of the foam but in my box the FRP is tightly bonded to the foam. Just resting on the foam on the FRP there is a gap which makes for a weaker structure. With the FRP tightly glued to the foam core it would be a stronger surface although still sensitive to a point load and puncture.

The main thing for me is that any damage is easily and completely repairable.

[nwdiver]

I used blue styro and fibreglass/epoxy.

The box was very uniform in dimensions so I carefully cut the board and beveled the edges to fit the bottom and the 4 sides, dry fit and shaved the edges until all was happy I pulled them out and put 1 layer roving and 1 layer of cloth on each panel using a nice flat bench to within 1 inch of the edge of the bevel about 2 hours work, the next day installed the finished panels and using 3 inch cloth stripes sealed the sucker up now I have the original 2 inch and the added 1.5 inch of insulation and a slightly smaller frig, all with the same compressor and cold plate I run run about 1/3 the time they did before the added insulation. I actually pulled the cold plate and compressor to replace them but on the bench they worked fine, so I realized IT WAS THE INSULATION.

[Rubikoop]

Originally Posted by skipmac

Probably. Will conduct additional, highly technical, scientific testing with two pieces of FRP.

Also, for the test I just set the FRP on top of the foam but in my box the FRP is tightly bonded to the foam. Just resting on the foam on the FRP there is a gap which makes for a weaker structure. With the FRP tightly glued to the foam core it would be a stronger surface although still sensitive to a point load and puncture.

The main thing for me is that any damage is easily and completely repairable.

To eliminate the variables of your highly technical impact studies, could you describe the kind of beans you are using?:-). The Nobel Prize people are awaiting your results before choosing a winner.

[skipmac]

Originally Posted by Rubikoop

To eliminate the variables of your highly technical impact studies, could you describe the kind of beans you are using?:-). The Nobel Prize people are awaiting your results before choosing a winner.

Since I was conducting a very sophisticated test I used only the best, a 15 oz can of Westbrae Natural Organic Fava Beans. For my control test I used a standard 15 oz can of Progresso Black Beans.