This is a design of a RMH that can be used for multiple purposes or to solve many problems as do all good permaculture designs. The design is mainly in the base of the apparatus. Figures RMHview1 and RMHview2 show the entire assembly front and back views minus the thermal mass that the exhaust pipe would go into. In the images some components are transparent so that everything can be seen in one view. The components of the assembly are the base, combustion chamber, 55 gallon drum, and optional water heating coil, optional wood chip vessel (to produce charcoal). Other optional components could be added for better serviceability like a wood stick feeder shoot at the same angle as the intake plate, as well as an ash rake and ash tray for easy removal of noncombustible ash material (which could be used to make lye or potassium hydroxide which has many uses including creation of soap used for grey water systems - i.e. potassium based soap better for plants than sodium based soap).
Figure RMHview3 shows the base, combustion chamber, and wood chip vessel only.
(Note there is more to come but I see that I can only add three attachments at a shot. Bare with me while I work out all this newbie stuff…)
(Continuation from my previous post…)
Figure RMHview4 shows the base and combustion chamber only.
Figure RMHview5 shows the base and water heating coil only.
Figure RMHview6 shows the base and 55 gallon drum (drum not modeled with much detail – i.e. basic cylinder)
Figure RMHview7 and RMHview8 show the front and back views of the base.
This RMH would be mainly for a garage, shop, greenhouse, or similar environment. It is a bit large for a house, but in some homes may be appropriate. The base and modular construction of this RMH is what makes this unit have many possible uses. This RMH can be used for water heating, making charcoal (to use for biochar), firing clay, and of course heating a built environment. Aside from the thermal mass this unit would be attached to, this RMH can be easily disassembled, moved, and reassembled. The base can be considered more durable and longer lasting given it is not exposed to the higher temperatures the combustion chamber and drum are exposed to. The drum and combustion chamber can be considered consumable given the lower cost of materials they are made from.
Different sizes of combustion chambers can be inserted for different purposes. The chamber shown in presented figures is of a size that will accept a vessel to convert wood chips into charcoal. Human poop could also be added along with the wood chips to render sterile and useful for making biochar as well. I believe Paul might appreciate this given his healthy aversion to some other ways of dealing with this. At least this might be one of many ways to deal with this depending on specific circumstances. The volatile gases purged from the woodchip vessel during the pyrolysis process also provide additional fuel in the combustion chamber. A smaller combustion tube can be put in place if the RMH is only being used for heating.
I also believe the combustion chamber temperature can be controlled in such a way as to fire clay. I am interested in experimenting with making pots and items in general but more specifically for clay pot or olla irrigation.
I got a quote from a local sheet metal shop to fabricate and weld the base out of 1/8th inch steel for $794 Qty. 1 and $568 for Qty. 5. Even $568 is a bit more than I want to commit to this for now. I am posting this to get some feedback and also see if there are others that might be interested in collectively making this or something with the same features. I can provide all mechanical drawings of the base needed for you to go ahead and make it yourself or get it made if there is interest. This might be a good opportunity for some sheet metal shop to make some side money if this thing is as useful as I believe.
Of course, I cannot claim this thing is useful for anything. Use the design at your own risk. Be aware I cannot possibly provide all details about this design here. For example you might notice the 55 gallon drum is up-side-down and sitting in a 1 inch high trough. Why? This is to fill the trough with some sand so that the sand will make a sufficient gas seal.
Please contact me if you have any questions.
I guess this is a bit much for a newbie, but I have been visiting this site and have been involved in renewable energy and permaculture type activities for a while.
Solar Station Construction Plans by Ben Peterson -- ebook