Hi all. I'm working on a small project and could use help. I have an 3/8" thick aluminum box that is going to be placed outside. The dimensions of the box are 33"x33"x33" and inside the box there is a 3/4 air gap on all sides that is covered with 1/8" hdpe platic walls. There will also be a 100w output within the box. Lets say I want to maintain 70f degrees inside of the enclosure. Using a DAQ setup I have been able to determine that the surface temperature in direct sun reaches ~130f and the internal hdpe walls reach ~100f. Using r3.5 foil/bubble insulation behind the hdpe gives me a lower internal surface temp of 90. My questions are: 1) how could I calculate the actual R value of all the surfaces using my DAQ setup? This would be useful to mathematically test changes to the enclosure. 2) How could I determine the BTU's needed for cooling to maintain 70f? Would a simple conduction equation like "btu=UxAx(t1-t2)" be all thats required if I want to assume all external surfaces are the same temperature? 3) If I assume the internal air volume is 20cuft and 100 degrees could I use btu= (t1-t2)x1.08xcfm to determine cooling required to bring the air down to 70f when the box has been unconditioned for some time like a peak cooling load? " 30x1.08x20=btu?" 4) Finally, what would be the equation to determine actual temperature differences between one side of surface and the other. If I have an r4 insulation board that is 100F on one side how can i determine the temperature rise on the other? Thank you for reading! Any input would be appreciated!