Cindy Mathieu wrote:Pellets, by their nature, have a lot more ash than cord wood. Moreover, they have some amount of embedded energy because a machine somewhere else had to make them. They are very uniform, so what happens to all the material (such as bark) which doesn't match the color the pellets are supposed to be?
Pellets can be made from a wide variety of pulpy biomass. They are not even difficult to manufacture at home. They use up the last of the scraps from manufacturing and construction process, woodworking, etc. I am not concerned at all about the color of my fuel pellets, so I have no aversion to bark and all being used to make pellets as long as it burns.
Cindy Mathieu wrote:
Also, the point of the mass in a rocket mass heater is the same as the masonry materials in a masonry heater. You burn fires to heat up the mass of cob or the mass of fire clay bricks and then you don't have to tend the fire all the time because the mass is still giving off the heat.
If one had an easy method to automatically feed a small combustion device with fuel creating on demand heat for 8 hours, the entire design and mass of a RMH would hardly be needed. All of the clay, cob, brick, and barrel could be eliminated creating a totally different animal, with different functionality.
Keep in mind that RMH with huge thermal mass cob bench is not practical in tiny spaces, for camping, for trailers, or for moving from the living room into the workshop, etc.
This addresses a different function than the ideal way to heat a standard home. For a standard home application, I would rather have a large thermal mass always radiating.
But even in that situation, some kind of 6 foot fuel that fed itself into the burn chamber so the fire could be unattended for 8 hours would be nice. What if all you have is a bunch of 1 foot twigs? How often would you need to be replacing them? Surely a 6 foot piece/pieces of fuel that fed itself in automatically would require less fuel tending.
also if the fuel was always occupied a uniform space in the inlet tube, would that allow for new modifications to RMHs which precisely dial in air intake and exhaust ratio.
One thing that RMH/rocket stoves do not currently have is any kind of "dampening" function.
The air intake and exhaust is always the same opening, the only thing which alters flow in an RMH/rocket stove is how much fuel are you burning at one time, and or how packed with sticks in the intake opening. There really is no way to adjust the air fuel mixture to slow down a burn, to lean the mixture, or to conserve fuel etc.
I think the current design and functioning of RMHs are excellent, these things I am proposing simply add to the current functionality that already exists, they do not supplant it.