I tend to leave the science to the scientists. The walls of a teardrop are too thin to leave the kind of air gaps that are recommended for buildings. My approach was more to try and build a heavy duty, teardrop shaped "ice chest", so I filled the voids with whatever insulation I was using. The walls are filled with one layer of pink foam, the flat part of the roof with 2 layers of pink foam and the curved part of the roof with 3 layers of foil bubbles, the floor is filled with 3 layers of a white styrofoam like material that is much like pressed styrofoam balls (a real mess to cut).
I do not know if my approach is a good one or not, it could be that I would be just as well off with no insulation. I do know that on those 100+ degree days, I can get it colder inside the Escape Pod than I can in the house. The TD is a great place to cool off with a pint of stout or ale on those hot summer days. So it works for me.
