Thank you for the VERY detailed reply! WOW!
After seeing your reply Im not sure wow well I conveyed my design conceptions. Actually after rereading what I wrote I know I could have done a much better job, sorry:(
1st) Yes, there are 3 different exhaust ports which can all be closed and opened independently from one another. I was planning on having one go through a very large cob bench, another under the kitchen floor, and the last running though cob stairs ( lots of surface area that I dont want to waste).
2nd) From what I understand about combustion, specifically wood combustion, turbulence in the burn chamber should result in a cleaner burn.... Not sure though since I've never built one much less ever seen one! lol
3rd) The feed tube which supplies wood to the burn chamber is surrounded by a 30" barrel, heated by exhaust gasses coming from the riser/double barrel. Kind of a combo 'preheat/dry out your fuel' and 'humidify the air' thing. After all, why burn cold or even room temp logs when a small design altercation can increase efficiency? The reason I want it to give off hot humid air is because it gets so bloody dry in the winter here in Norther New Mexico.
4th) Well I guess thats actually all there is. Do you really think zoned exhaust is a bad idea? Has it been done before?