Great thread, I have a homemade solar kiln. I use a squirrel cage fan for circulation. The squirrel cage blows into 4"galvanized dryer pipe with 1" holes drilled in it. They point upward and keep the air circulating really good. I also have a dehumidifier but to tell you the truth you don't need it unless you have continuous cloudy days. When the temp gets up there the humidity is so low that my humidity gage won't even register and the dehumidifier isn't needed. Really it wont even run when it gets too hot but it's so dry in there at high temps; like I said you don't even need it. I have to lower a tarp over the panels so the temp stays down. If I leave the tarps rolled up on a hot sunny day, it will get over 150 and dry too fast. I've got mine running as we speak with 4x8, 4x6 and 2x4's yellow pine.
