read THE book a while ago, and been interested in RMH for a while.
Also done a couple of portable rocket stove while on a nomad bicycle community (www.ecotopiabiketour.net) and loved to cook on them, fast to lit and cook and less wood burnt (less to pick )
me and my partner are now building a tiny house, around 4mx4m space and always fancied the idea of a rocket mass heater bench ... starting now to plan mentaly where it would fit and start looking for materials.
i never saw one live, and realized all the videos and pics i saw the barrel stays very high, and never anyone praises it for the cooking hability on top of the barrel...
is it possible to design a RMH that also is used for cooking regularly (so the top of the barrel shouldn't be too high)? could i follow the 15cm (6'') design of the book and shorten the barrel? what would be that limit? and what's the consequence of a shorter barrel? i remember reading about making the barrel longer would make it burn more efficient, does a shorter one not be able to draft?
6"/15cm is about the smallest size standard RMH that is said to be easy to build right - heat output scales down with at least the square of the diameter, and air friction effects don't scale down with diameter but become more significant. A 4" system is possible for experts or careful and lucky beginners, smaller than that does not seem to work.
However, a batch box combustion system has been tested to 4" diameter (possibly smaller), and as long as you follow the published specifications it should work well.
http://donkey32.proboards.com/thread/734/peterberg-batch-box-dimensions You can add whatever thermal storage arrangement you desire after that, and in the Portuguese climate it will probably be sufficient to heat your small home. A 4" batch box would be much easier to tend than a 4" J-tube which would need sticks added every few minutes.
Location: north-west coast of iberian peninsula
posted 2 years ago
never read about those batch box rocket mass heater (is this the name?), is there any good posts/info on them i shouldn't miss?
looks like a possible solution, but but i would need to combine a cooking solution aside, is there info on using the same exaute tube for two diferent heaters?
Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''