I'm trying to wrap my brain around solar dehydrator designs. I've done a bit of research and I like the Appalachian State design that provides a long tunnel that pulls air from the bottom and lifts it up through the food trays. However, I would really like to build something that is capable of drying sauce type items. I want my solar dehydrator to be just as versatile as an electric one, and that means the ability to make items like tomato paste, fruit leather, and other items that begin in a fairly liquidy state. My concern is that most of the solar dehydrator plans I've seen focus on pulling air from below that rises over the racks of food. Is this adequate for liquid food items that require a solid tray? I've heard of designs that pull air in from the top and bring it down over the food -- I haven't been able to find a design like this, but it seems to me like this would be more appropriate for drying liquid items. Any insight or links you have would be much appreciated!
On a related note, I would like to try making black garlic, but I don't like the idea of leaving an oven or rice cooker on for the ~40 days required for the garlic to ferment. Has anyone use solar dehydration to make black garlic? My concern is that the temperature would dip too much at night, so I'm also interested in insulating the dehydrator as much as is reasonable.