Ice Box Conversion to Spill Over Fridge/Freezer

[Typhoon]

Tonight will be the warm up time test of my little experiment. Then I will graph the data and post it here as well as starting a new thread on the subject .

So far what I have seen has confirmed other research I have found on the WWW.

This is the graph that gave me pause in recommending Polyiso to my customers . I am more concerned with it in freezer only applications.

This was the source of the image .

In Cold Climates, R-5 Foam Beats R-6 | GreenBuildingAdvisor.com

Regards John.

[Typhoon]

Originally Posted by SV THIRD DAY

Yep...two 7CF Test Boxes each set up with 4" of PolyIso vs 4" of Blue Board.
Published the data a few years ago...being around since 1968 has it's advantages....

I can't comment on your test data Rich , I haven't seen it .

Regards John.

[fallingeggs]

Interesting stuff. Perhaps I'll finish with all XPS (another 2" to 4") after the 2" of Polyiso.

[SV THIRD DAY]

Originally Posted by fallingeggs

Interesting stuff. Perhaps I'll finish with all XPS (another 2" to 4") after the 2" of Polyiso.

Hold on....
Will all due respect for John's testing, lets not birth another chat room internet rumor/myth that once alive will be impossible to kill.

First, while John's test is interesting how does it relate to your real life refrigerator and freezer box? Are you operating in the temperature ranges of his test where the outside temp is below 40-degs F or in the tropics where it's 90 degs F? So it the data point meaningful or will running with it lead you astray?

Everyone knows that polyiso loses some R-valve at the lower temps, but the question that this data point does not address is to what depth does this lower temp affect the polyiso. The entire 4"? 1" without that data point you can't make the proper decision. Don't forget that polyiso has a 33% better R-value than blue board to start with, so you have to understand where the cross over line is between lower temps on the inside of you box vs better R-value vs the outside higher temps.

In our 7CF test box at 70, 80 and 90 degs F ambient temp we found that the best insulation combination was 1" blue board on the interior followed by 3" of poly iso. Why suffer from 1/3 less R-value in your given space of insulation because the first 1/2" or 1" of insulation may lose some R-value due to the colder temps on the inside of the box only!

This is the perfect example of how a little info can send you down the wrong path without looking at the issue in greater context and as a whole.

[Typhoon]

Well said Rich .

Im not trying to start another INTERNET myth , you know how I feel about that , Im just trying to supply data . How people choose to interpret the data is up to them .

You know I have always been a proponent of first layer blue board to the cold in building any box.

As I mentioned before . I am not concerned with Polyiso at refrigeration temperatures , but more at deep freeze temperatures .

To do a proper real world test I would need to build a box with temperature sensors every inch to observe what temps the Polyiso is exposed to . If just two inches of polyiso looses 50 percent of its r value in the lay up it negates any gains at the outer layers . So my synopses is why bother at all in a deep freeze scenario ?

For me, at the moment I may not recommend it anymore . If I build 6 inches of blue board , I can be sure that it will be R30 or more, With the Polyiso in the mix, who knows.

Let me conclude my tests and get it all graphed before I write that in stone .

Regards John.

[Typhoon]

Sorry just a follow up note. During the test I did not see any better performance from the polyiso over the blue board even at room temperatures. So 33% better R value ???

Regards John.

[SV THIRD DAY]

Great John....Then we can start trying to dispel the info Nigel was passing out at the Annapolis Show...ha ha ha

Oh and on edit I see you other question about 33% better R-value.
I'm using the published R-values of the two products and I saw similar differences in the 7CF test Box.

[john61ct]

Originally Posted by SV THIRD DAY

In our 7CF test box at 70, 80 and 90 degs F ambient temp we found that the best insulation combination was 1" blue board on the interior followed by 3" of poly iso.

Again, to generalize the rule for a built-in ice box:

An inch of XPS on the cold side, enclosed by as much polyiso as you can fit on the outside.

The point is buffering the coldest temps from the polyiso, then taking advantage of its superior R-value.

I suppose a cheap portable cooler spec'd with 2" max could go to 1/2" XPS then 2.5" polyiso.


If money were no object, for limited thickness situations an Aerogel-type sheet, or even vacuum panels, could be substituted for XPS, right?

[SV THIRD DAY]

Originally Posted by john61ct

Again, to generalize the rule for a built-in ice box:

An inch of XPS on the cold side, enclosed by as much polyiso as you can fit on the outside.

The point is buffering the coldest temps from the polyiso, then taking advantage of its superior R-value.

I suppose a cheap portable cooler spec'd with 2" max could go to 1/2" XPS then 2.5" polyiso.


If money were no object, for limited thickness situations an Aerogel-type sheet, or even vacuum panels, could be substituted for XPS, right?

That's certainly my thoughts Amigo.
Technautics used to sell Vacuum panels, but stopped once the cost started going out of control (like $2500 for an average size box).

[Typhoon]

Originally Posted by SV THIRD DAY

Great John....Then we can start trying to dispel the info Nigel was passing out at the Annapolis Show...ha ha ha

Oh and on edit I see you other question about 33% better R-value.
I'm using the published R-values of the two products and I saw similar differences in the 7CF test Box.

Lol yeah Rich ,

I'm still pondering if I should post the picture I showed you , that would light up a few wild forum posts lol .

Regards John

[SV THIRD DAY]

Originally Posted by ColdEh Marine

Lol yeah Rich ,

I'm still pondering if I should post the picture I showed you , that would light up a few wild forum posts lol .

Regards John

Ha ha....ya forget about the Climate Change or Anchoring Threads.
Maybe you should save is for winter when everyone in the colder climates are looking for some online entertainment!

[john61ct]

You guys are such teasers

[Colin A]

To the OP. Did you try emailing or calling Cleave up at Seafrost? He might be able to help switch the system over to electric, Might be a bit more expensive then your original plan thou.

[fallingeggs]

Originally Posted by Colin A

To the OP. Did you try emailing or calling Cleave up at Seafrost? He might be able to help switch the system over to electric, Might be a bit more expensive then your original plan thou.

I didn't specifically ask, but I am also sure the price would have been high. Plus, the old holding plate was huge, making installation a hassle.

[fallingeggs]

Layered in 2 more inches of Polyiso on the sides, so the box is now fully lined to 3 inches (except for the top/lids):



The fridge side will get a last layer of 1" XPS. Going to add one more inch of Polyiso to the freezer side and check measurements again before deciding whether I do another layer of Polyiso or finish it with XPS.