Why no insulation in Roadtrek

[avanti]

Originally Posted by wincrasher

That test data related to the skin of the vehicle. Not the heat transferred to the interior of the vehicle. The differences are negligible inside, and pale compared to the contribution of the glass area.

See my link in message #55.

What you are claiming is not remotely plausible.

[ProseMan]

Originally Posted by InterBlog

Multiple comments here... this is proving to be an unusually good thread.

(1) I sure would like to see some photos of the Aluminet and the mylar solutions. Those are both innovations of which I was previously unaware.

Edit: I'd also like some info on how the Aluminet packs down. I'm looking on sellers' websites but I'm not seeing that information. How bulky is it?

If you go back a few pages on this thread, you'll find my picture of the aluminet attached via magnets. It is a bit bulky: folds up like a down comforter. This is due to numerous slits in the material. The mylar space blanket would be more compact, but the real advantage to the aluminet is that wind will travel through it, so you can open your window vents. Also, you don't have to worry about the wind catching it and blowing it off the RV.

[BBQ]

.

Lots of tests on youtube

The results are all over the places.

[GeorgeRa]

Originally Posted by BBQ

.

Lots of tests on youtube

The results are all over the places.

This fellow conducted a very scientific experiment to prove that the Earth is flat, results were inconclusive but the lucky fellow survived. https://gizmodo.com/at-long-last-fla...o-b-1824059035

So yes, our great Internet is loaded with inconclusive quasi scientific experiments.

[InterBlog]

@Booster, if all goes according to plan, I'll have 3M Crystalline on my cab windows in about 2 more days. I had scheduled it for an earlier date, then serendipitously located a great price on a windshield replacement ($285 + tax installed) and decided to do that first.

The T1N Sprinter windshield is notorious for leaking, and as it turned out, mine had started leaking and I didn't know it.

The timing has been auspicious. My main motivation was not putting a hella expensive tint on a 12-year-old windshield, but it turns out that I needed a windshield either way, whether I was planning to get tinted or not.

[Reed]

I mentioned in post #46!that the surface of our Roadtrek was at least 5 degrees F cooler behind the Aluminet that that indirect sunlight. I neglected to note that the Roadtrek is bright white. I noted discussion on effect of color on reflection of sun. Was a moderately high level optical physicist for US Army Research Labs at White Sands Missile Range. Color does have effect.

[booster]

Rate of heat conduction formula


Rate = k•A•(T1 - T2)/d


k is the overall heat transfer coefficient of the wall test area, and would include heat that goes into the van by conduction but not a infrared through the glass. Color will not make a difference as you are using the skin temp of the surface for the calculation. It is easy to measure that temp with an infrared themometer.



A is the surface area of of the test area.


d is the thickness of wall area


T1 is outside wall temp


T2 is inside wall temp


k, A, and d are the same for the same test wall area or van, so that just leaves the two temps. If you raise the outside temp, the heat conduction rate goes up until the temp stabilizes. The exact place that temp stabilizes will vary depending on how much heat the van loses in the non sunny, and sunny, areas to the atmosphere. If you have just little bit of sun hitting the van, and it is cool out, the stabilization point will be more lower than the skin temp in the sun than if the entire van was in the sun with same skin temp. More sunny area to cool area and the inside will stabilize hotter. A good breeze increase the heat loss out of the van, so the inside will stay cooler when compared to no wind, but same sun conditions.

[InterBlog]

Originally Posted by ProseMan

If you go back a few pages on this thread, you'll find my picture of the aluminet attached via magnets. It is a bit bulky: folds up like a down comforter. This is due to numerous slits in the material. The mylar space blanket would be more compact, but the real advantage to the aluminet is that wind will travel through it, so you can open your window vents. Also, you don't have to worry about the wind catching it and blowing it off the RV.

My bad... now I see it - it's in #28. That's a similar idea to the side shroud I made. Mine does not extend down the side of the van, but I was aiming for small size (it folds up to about the size of a large ham sandwich), plus I knew the black-masked windows were the main offenders.

I can open our flap windows - a little bit of "give" and the neodymium magnets can be moved enough to accommodate them.

[BBQ]

https://www.youtube.com/watch?v=8Kz3CXlgp9A

[silex840]

Cool gadget, but I prefer just parking under a shaded area especially since that device will cover my solar panels anyways. Now just need to wire in a quick disconnect port...

[InterBlog]

Originally Posted by booster

......
Personally, if I were trying to get the solar heat gain from windows reduced as far as practical, I would tint all the windows with Crystalline film, even the tinted windows. It would likely be as effective as the mylar, or close to it, and you still have room for an insulating shade for cooler weather or insulating, and you don't have to take it on and off. The largest eyebrow that you could reasonably put on the windshield would also help, especially when driving, and a reflecting solar accordion shade the windshield when parked.
....

Two pics of my CR-70 job below. It's on the whole windshield, so on the lower photo, the view is through two layers of tinted glass, not one. I had it done yesterday and have not had a chance to test it through all conditions obviously, but so far, I am very pleased. It's certainly not too dark. I can barely tell that it's there at all. I still need to use my sunglasses.

Now, as for the possibility of having ALL windows done...

We have six more windows that I am quite sure I could do myself in CR-70, if I could get hold of the material. The reasons why I say this are (1) I watched the installer through all phases of the install yesterday, (2) the other 6 windows are small, (3) the other six windows are flat, and (4) the other 6 windows are already tinted and are not continuous viewing windows, so the job would not need to be as perfect as the cab job needed to be.

The real booger with this stuff is if it needs to be fit to a curved window. The skill is in the shrinkage phase. If that's not required, then it's an order-of-magnitude easier task to install it.

Anyway, just as a cost reference, the only bootleg sellers that I can find are out of Hong Kong. If I were to acquire enough of this stuff to do, for instance, my two back door windows, the price would be $125 plus the cost of the solutions used (haven't figured that part out yet), vs. maybe I could talk my installer into doing that little job for about $300 - $400 as a valued return customer.

Bottom line, it's hellaciously pricy stuff either way.

[booster]

That's right, I forgot that in Texas you can tint the windshield. We aren't allowed that in Minnesota. We had to be careful even putting on an eyebrow so it looked like a factory top tint on the windshield.

I also watched and asked questions of the installer when ours was done. He also said that learning how to use the heat gun to get the curved surfaces to shrink right on installation was the hardest part of the job. Also very important to have a good fixture for spraying and stripping backing to prevent buckling. I was very glad we chose to hire it done, and we very rarely hire anything done.

I have read both positive and negative about the non authorized sellers of Crystalline. It does appear that quite a bit of it may be counterfeit. It is a very complex product of lots and lots of layers, so the counterfeit stuff would have to be some other product or off spec stuff from 3M (which would be highly unlikely for them).

[InterBlog]

Not exactly, re: Texas. Full windshield tints are categorically illegal. However, it is a defense to prosecution to have a medical justification. For reasons I won't get into, I could get one of those if I needed it. But unless the tint is very heavy, state inspectors tend to turn a blind eye (this is Houston, after all - MANY people tint their windshields). I'll only go for the medical script if they make me do it as a condition of passing inspection (it'll cost me a co-pay which I'd rather spend on the van).

The only motivation for aftermarket selling of CR-70 is that the bootleggers up the cost per square foot. I suspect what's happening is that legitimate installers are buying rolls and reselling them at something like 1.5x. And then the bootleggers are chopping them into smaller pieces that they are selling at 2x per square foot. Something that. But I have no doubt that there's also counterfeit product on the market.

Aftermarket selling can't be easy. Within minutes of my job, 3M had emailed me a 16-digit serial number associated with the lifetime warranty. They have this stuff under tight control. My warranty papers specify the exact windows on which it was installed.

[Saldar]

Originally Posted by wincrasher

That test data related to the skin of the vehicle. Not the heat transferred to the interior of the vehicle. The differences are negligible inside...

The silver Honda Civic (shell SR 0.57) had a cabin air temperature of about 5-6°C (9-11°F) lower than an identical black car (shell SR 0.05).

Read more at: https://phys.org/news/2011-10-silver...ooler.html#jCp