Hi Gilbert, I sent a PM to Larisa to let her know about your question and here's her answer:
I don't see the original post so I'll answer you directly and hope that you can pass it on. I think painting the back of the glass would cause a thermal failure in the window and crack the glass. Might be an interesting experiment, but instinctively I think it's a wrong approach. Metal gets hot in the sun even if not painted black, and it's this heating and reradiation of heat through the metal and towards the food that makes the design passively move moist air up and out. We've done a little experimenting with our design to incorporate ideas that folks have come up with over the years in our dryer workshops. In all cases those ideas further complicated the building of the dryer and none were ultimately more efficient or convenient. We stand by the original design concepts, with modifications in materials available if needed. Hope this helps clarify the question.