Rocket stove water heating.

Hi my name is Anthony and this is my first post here though for some time now I've enjoyed the huge amount of creative, intellegent and original information generously shared by its members. The main reason I haven't actively participated truth be told is that forums tend to be a huge time sinkhole, for me anyway. Also i didn't feel I had anything new to offer nearly always finding info on ideas peaking my curiosity. Recently though Ive been mulling over some ideas that I haven't found extensively covered, though I haven't recently done a search. Apologies in advance if these concepts prove redundant. First, let me say that Im totally aware of the potentially explosive nature of heating water in a closed enviornment without propper safety precautions and sufficient knowlege of these systens. From what I inderstand about rocket stoves, optimum performance is basically the rising of heated air potentiated by lower surrounding temperatures causing enough thrust to push through unconventionally long passages through thermal mass by which the air is gradually cooled, reducing back resistance to be finally vented (simplified). Thermal equalization that would lessen optimal rocket stove operation is greatly slowed by the mass. So if you wanted to reduce the amount of mass, (like in a case where your spouse saw it as just a whole lot of mud and rocks in her living room) you'd have to slow thermal egualization another way. I was wondering if coils of copper pipe containing constantly moving water from a fairly large tank could be wrapped inside next to the outer tube insulated from inner the heat riser? I thought this could (as well as heat water) help cool the decending air outsuide the riser. Would the coil being wrapped around the outside of the insulated tube(s) inhibit downward airflow? Also I thought somehow containing 4''+- thermal mass (loose for pipe expansion, sand ,powdered clay etc), at the top of the barrel with copper pipe coiled within. I think these are both places where immediate cooling would beneficially reduce resistance to downward airflow. Id appreciate any input here because though ive read a lot about them, I have zero physical experiance with rocket stoves. Thanks

I built a rocket the idea was to have it outdoors and heat water like one of these outdoor wood boilers. From that experience I would say to wrap the coil around the base of the barrel as opposed to on top of the lid. you will also want to have the lid removable.

The first thing to remember about rocket mass heaters is that they are primarily a conductive and radiant heat source. Trying to trap their output and move it to a remote location will make the system much more expensive and much less efficient. A remote location like outdoors will also make it much more of a chore to tend the fire, unless you build a batch box style firebox to reduce feeding frequency; then it will just be an occasional inconvenience instead of a frequent one.

Any system which puts closed-circuit piping near the hot area around the combustion zone runs a risk of steam explosion if the power fails or circulation is stopped for even a moment. Professional-grade design and construction can minimize this risk, but not eliminate it. Safe systems for water heating have been developed, centering around heating an open tank, with circulating coils inside the tank and not touching it. As pressurized water has a higher boiling point than atmospheric water, the coils will never flash to steam even if the tank boils or goes dry. There have been several descriptions of such systems in this forum.

Another point to consider is that the downward flow in the barrel is only necessary because the heat source is typically higher than the mass bench being used for a radiator. If you happened to have a setup with the top of the riser just below floor/bench level, you could go straight horizontally into the mass ducting. So your system configuration could change depending on the relative elevation of heater core and heat storage reservoir.