Instead of using one continuous sheet of alum. for the sides I did it in overlapping parallel strips. This is then painted black as you see in the pics. Same idea as the dull side, and shiny side of aluminum foil. One side absorbs heat and the other reflects. The rood is a double layer. There is a skin of aluminum (again in strips), unpainted. On top of this I cut a tennis ball in half and siliconed it to the center of my aluminum roof, then placed UV resistant FRP on the top. This gives the FRP a domed shape before having all the sides caulked and then screwed down giving it an air tight seal. This gives me a layer of insulating air. The white top reflects the sunlight and heat causing rays. So in a way the trailer is much like a radiator. The roof keeps the area with the most surface (that is towards the sun) from getting hot, and causing a heat transference through the ceiling. The black sides absorb some heat, but the shiny side reflects the coolness. So essentially the cool air has no where to go, so it warms up very gradually.
I got in the trailer and opened the windows after getting to the site, and watched the temp rise to the same temp as outside in a matter of minutes.
Whats funny is I thought very hard about all of this, and it never occured to me that the only time I would be in the trailer was at night, when it didn't really matter anyway. Plus I am no engineer, so writing all of this out it may sound and seem like total B.S. (Which it may be). It really comes down to anything with a white roof is going to stay cooler longer.
Now if they only made white shingles.
