Jared wrote:I couldn't find the foil polyiso panels in my mid-sized Canadian town. Apparently they're not used very much as a building product outside the US. The only ones I could find were primed with a thin layer of white paint and I figured painting them was easier than gluing foil to them, although I may have been wrong. The research I've done suggests that the different between white and foil is not as big as you suggest?
It was basically a hybrid between Figjam's bucket and box designs. It turns out that there is a lot of nuance in Figjam's designs that you lose when you fuck with them. Next year I'll just make a bucket.
I've been doing a lot of looking into heat reflection for on-playa use. There's a meaningful difference between foil and white heat-reflective paint, and a huge difference between those and white paint, even if gloss (which has a slight edge over flat). White paint will reflect sunlight away, but not much of the infra-red in the sunlight or radiating from heated ground. The foil sided sheets are between 70% and 90% reflectance, depending on how shiny the foil is. If you go with gluing the "space/survival blanket" (aluminized mylar) to the sides of your existing structure, it rates from 94% down to 70%, and lower if it gets crumpled. The over-all winner seems to be: foil-sided bubble-wrap
, comes in near 94% before it gets crinkled a bit (which lowers the reflectance slightly), and if you manage to crinkle it a lot it's usually limited to a low end of 70%, as the bubble wrap limits how much it can get crinkled.
Keep in mind that 70% does a lot of heat reflectance, and of light that would get turned into heat. So, for hexayurts on-playa, the foil-sized polyiso at 70% to 90% is the choice - good to great reflectance, and the foil is already attached and likely to stay there. Given you've already used paint on the sides of yours, you might have issues getting foil to glue to it or stay there. Your best bang for the buck with what you already have might be a paint with lots of shiny aluminum pigment
, the more shiny aluminum the better
as it will reflect heat away more. There is a rattle-can paint with aluminum in it; it's been posted on eplaya.
gyre wrote:Rustoleum HD Aluminum is 50% aluminum.
You can burnish it to a fairly reflective sheen, even after it is dirty. I use a paper towel for that.I brush it on, but it can be sprayed.
You're at some disadvantage with such a small structure. Anywhere inside is close to a wall where heat can duct from the sun-heated ground right on the other side. With larger hexayurts, this doesn't seem to be a factor, balanced with the larger floor area that is shaded and will sink heat away into the ground, which is around 62F. I have no idea how much of a factor this may be.
And your tarp edge can absorb heat. But your stuff seemed to provide shade on the sun-side of the structure. If you have a heat problem with your structure with a shiny coating on it, you could get one of the space-blanket/tarps:
Available lined. With a stronger backing (typically orange). Also available with a heavier reenforcing lining/backing, which is typically a cheap plastic tarp or ground sheet (commonly red, blue, green or camo), often with grommets.
And stake that out on the ground to keep the ground right next to your structure protected from heat. Such a tarp could be installed over your structure, but that's a pain and has to be secured against wind.
But, with a shiny heat-reflective surface on your structure, or even exactly as you are right now, I'd expect a working swamp cooler to more than do the job you need.
Figjam's bucket cooler is the tried & true, but for your size of shelter, note that he reports that in the middle of the day he has to wear a sweater in his size of shelter.
You might be better off trouble shooting your smaller design. Looks like you've already got the correct battery. Post images and we'll see what we can do.