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Originally Posted by Jim & Susan
...The charts seem to show that the Prodex product is just a bit more efficient than the Homey D foil, which is just slightly more efficient than the pink stuff insulation. Is that about right?
Is there any real reason to believe that these materials will act radically differently in warm weather than cold? Not trying to dissuade you from running the warm weather tests, just thinking out loud.
BTW, I find it amazing that you still have an XT machine still functioning. That’s gotta be some kinda longevity record all by itself.
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I, myself, am a longevity record.
I didn't think I'd see the millenium. Not age, mind you, just risky business. BTW I have 16 of these ancient "laptops" that run on 12V, 1 Amp. If you're a DOS nut and need a data logging machine, let's talk.
Yes, the materials will potentially act differently in the heat. This is only intuitive, but when the outer skin is heated by the sun and is easily 160+ degrees in the desert, radiation might predominate. In cold weather I "feel" like convection and conduction predominate. The foil insulation should have interesting properties in a radiation environment.
Your interpretation of "slightly better" is influenced by the small difference in the numbers in the data. But don't forget that the other five walls are very nearly swamping the panels' performance. That's why I'm going to do tests with a stabilized water bottle position and an internal air temperature sensor. I think those two changes will show quite a bit of difference between the different insulations. Stand by for data.
For those interested, I like the idea of an
expanded foam test and will do one this week (do you all agree that using the "low expansion" canned foam at HD will suffice?). I've got two more sets of panels (thank you again,
Aerowood), plus I found that I can disassemble a panel without significant damage. I mention this because when I get to the warm tests, I also want to coat the outside and inside of the outer panel with white paint to see what increasing the reflectivity and reducing the emissivity of the outer panel does to its heat transmission--this is more important in a warm weather test than in cold.
WARNING: youse guys are focusing on the insulation performance and forgetting that I'm
not simulating the ribs. I'm no expert, but I would bet that the
ribs transmit 30-50% of the heat through the shell, if the cavities are well insulated (less of the total if the cavities are poorly insulated). So, putting some foam tape, felt, or cork along the inside flange of the ribs before your reinstall your interior skins would be a significant contribution, even if a thin strip of this stuff only provided a small R-value. Small is bigger than zero, or so I've been told. I believe
UWE or someone did this and noted it in a thread.
Zep