Do a Google search for 'kiln' and you will find all types of setups for drying stuff like wood, this one is simple and best of all it's free.
When I got into wood turning one of the first things I started doing was staying on the look out for free wood and that meant collecting trees that had fallen or been cut down for some reason. It didn't take long to amass a rather large pile of wood that needed to be cut into turning stock and one of the steps in that process was drying the wood. There are a multitude of ways to dry the turning stock and this is one of those ways.
So... first you find a (free) refrigerator that someone needs to get rid of, you load it up and bring it home, you give it a good cleaning and then you drill a bunch of 2.5 inch holes in it. After that you install a small computer case fan at the bottom of this free fridge, place a small light bulb in the bottom of the unit and then you load in some wood that needs to be dried and fire it up.
There are a few things that it still needs, like a light in the bottom, but other than that it's working.