Joe,
We find ourselves in a pretty similar situation. I first started looking at
Rocket Mass Heaters and decided I'd see about doing one in my basement. Glenn is right, doing a traditional
rocket stove is going to chain you to the area for as long as you intend to keep it going. Fortunately, there is the Batch Box
Rocket Mass heater which might be a solution to your specific build site.
After consulting with Glenn and Peter Van Den Berg I have decided to go with the Masonry Batch Rocket for my basement
dragon due to the fact that I have only 7 feet from slab floor to
wood joist ceiling. The brick, with an additional heat shield will spread the heat out more evenly and prevent the ceiling from too much heat. The Batch Box will allow me the luxury of filling it up and letting it burn with the door closed so i can get a compete burn without having to tend the fire constantly. BBR's are said to have a burn cycle of about an hour.
I'm not an expert, but I also have a tall chimney and my suggestion for you is to build your rocket close to your chimney pipe so you can use that heat source to warm that pipe to induce a positive flow. I am also going to use a bell bench whereby the hot gases will flow through a hollow cavity in the bench structure that will be built with
concrete block, patio slabs,
cob, and topped with sandstone slabs of reclaimed old
city sidewalk from here in Toledo, Oh. Bench Bells are said to be much less restrictive to flow and still do a very good job of distributing and storing the heat. I might add that I replaced the door to my basement steps with a louvered door to allow the supplemental heat that is presently supplied by ventless Nat Gas
heaters to flow upstairs. You might want to do the same.
Now if all this doesn't seem complicated
enough, I'm going to embed some copper tubing under those sandstone slabs in the cob to provide a way to regulate the bench temperature and capture any excess heat that might otherwise make the bench uncomfortable and divert it to my Drainback
Solar Thermal
hot water system. But that's another story.
I hope this provides some food for thought.