Rocket mass heater for small wooden house

[janis968]

I am new in this forum and would like to hear your opinions and advices on rocket mass heater project for small wooden house 20 sqm with bedroom on second floor. I am from Latvia and during the winter for couple days or even some weeks outside temperature could drop till -20 degrees Celsius. House has average insulation. There is installed insulated ceramic chimney 200 mm on concrete plate and place for stove with max dimensions 1 meter x 1,4 meters and till 2,4 meters high. We already living in this house and heating with old Norwegian Jotul cast iron stove. Heats well during wood burning but cools down very quickly and needs a lot of wood to maintain warm inside the house.

That is why I would like to build mass heater with bread oven and water heater for 80 liters hot water boiler (it has possibility to use electrical heater or water heater). The mass heater should be big enough stay warm enough for at least 12 hours or even 24 hours. Could be some mix from Finnish mass heaters, Kuznetsov stove and rocket stove.

The idea is to get max energy from clean wood burning and store it in mass heater. Since  I have quit limited space for stove and at the moment I am looking in direction of batchrocket stove inside the bell - most probably with single bell and double walls. Bread oven could be directly on top of the fire box and water heater between the bell double walls - Peter gave me this idea. Since this is at the moment just a project I have questions.

1. Which stove could be the most efficient and cleanest way to get max energy from wood burning?
2. What kind of materials could be more suited for rocket stove - heat riser, fire box , bell inside and outside walls as heat storage?

I would be thankful for any advice.

[belgiangulch]

I recently built and installed Peter's new Shorty Core in my small home.
With its short stature and casual burn, a 5" version would be fine in your tiny home.

As far as an oven, you sure could build one but I have to wonder about regulating temperatures.
Also, I am not sure if adding an oven inside the bell would affect the overall Isa.
With any Batchbox design, there is no half throttle it's wide open only, and your fire burns quickly, cleanly, and very hot.
By building small fires that burn wide open, you might be able to hit a sweet spot in oven temps for baking.

I had not heard of the idea of putting a water jacket between skins, but it came from Peter, so it is a definite possibility.
However, in your build, I do not see enough room in your footprint dimensions, for water heating.

Getting a proper Isa for even a 5" batch could (but may not) prove difficult.

Planning is the hardest part of any build, especially a first build.

A very common apprentice mistake is asking an RMH to do too many things at the same time, usually, this results in poor performance and an unhappy builder.

Peter may have a better opinion on the viability of your plans.