For all you engineers out there--I'm going to build a solar dryer (for drying pineapple!) and I want your help. There are a lot of plans out there, but for simplicity's sake I've chosen the attached. Here are my questions--is this the right model for me? How should I tweak it? Would it make sense to replace the insulating material with something of higher thermal mass, like crushed glass, as one of my neighbors suggested?
I live 11 degrees north of the equator, near sea level. The sun is intense. Wind is limited. Annual rainfall is a little shy of 4 meters. Average temperature is somewhere around 23C. Annual evaporation is around 1.7 meters. Cloud cover is more than I'd like--but most days you get at least a few hours of good uninterrupted sun. When we get back into rainy season we might have to modify the dryer or choose a new design which we can run with firewood, but for the moment I'm hoping to keep this project green.
There are more dryer models here http://www.eric.ed.gov/PDFS/ED241766.pdf and elsewhere online.