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.
Alex,
ReplyDeleteCrushed class isn't a particularly great insulator. In most cases, it's actually the air that acts as insulation (hence glass fibre insulation).
As for insulation vs. thermal mass, they are slightly different. Thermal mass is usually merely a temperature buffer. Used in buildings, it will offset a cool evening with the warmth of late afternoon. Insulation, as you well know, holds the heat.
Because this difference, I'm surprised in mention of thermal mass for a dryer. I'd go for something of high insulation values, but I'm only an architect...
Gavin