Rocket Stoves for Yurt heating

[Rhyddian]

Any experiences of experimenting with Yurt heating with rocket stove mass heaters?
My experience with wood stoves is that it has two temperatures... Red hot or out! Im curious as to how i can store heat but have suspicion that heat would leach out of cob benches and dissipate quickly.
All the best from Scotland!

[Donkey]

Thermal mass done correctly in a bench can store heat for --- I've seen two days in mine here at home.. Even on the morning of the third day some residual heat is detectable.. Warm to the touch the eve of the second day..

High thermal mass in Rocket Stoves not only stores heat, it also mellows out high temp burn cycles by siphoning off the highs into storage. So far, the "too hot or out" syndrome appears not to apply.

While I haven't done a rocket stove in a yurt up to this point, I see no reason not too.. If you plan to use a standard yurt deck (western style) some provision will have to be made to hold up the tremendous weight of the benches, etc.

[Donkey]

Something not mentioned fully (if at all -- been some time since I looked it over) in the book, is that you can balance the amount of heat released instantly with the heat stored.
More instant radiant surface versus more bench and whatnot..
In my stove here at home there is no barrel at all.. My storage benches are good though perhaps a little short, so I've got great long term storage of heat. Unfortunately I'll need to open it up soon and modify somewhat to gain more instant, air warming off some radiant/convective surface. It tends to take overlong to begin heating my home.

[rhyddid]

Well the yurts up, floating on a rubble trench and some bolted tires, tied down with some serious storm ropesto resist these northerly winds and nicely insulated.

Built a 8inch system in the wood outside with firebrick after finding a large heat riser as an offcut at a friends building yard. My god it roars! Almost as much as the appreciation from the wealth of poeple who have popped by to have a peep.
Problem... its huge! I will relocate this system to a bothy i work at.

So, need to scale down. My question is how small. Considering a 4 inch system with a smaller burn tunnel. Has anyone tried goiing this small before?

Having loooked at KikoDenzers diagram in the mass heater book. Im considering something like this, with the Heat Exchanger built out of fire-brick. Unsure how to cap it at the top though.

Then, mostly to save space, i thought of sending the stove straight up from the bottom of the heat exchanger through the center of the yurt. (a good 106 inches) with some newly acquired titanium stove pipe and a silicone insert to sew into the fabric.

Also thought of insulating the stack somewhat, but unsure, as you say, of the trade off between radiant and stored heat.

Still have some large pieces of galvanised ducting from the large version. Which could encase the stovepipe and be filled with insulant.

Another somewhat contraversial question... I know its been made pretty clear of the dangers of installing a damper in a horizontal system. However, in a vertical system... once the combustion is complete and the burn chamber closed. Do you see any merit in having a damper near the top of the stack to stop the heat rising up and out?

In the meantime, Ive put in a small woodstove near the wall, which reduces the stakes somewhat by ensuring some heat for my partner! It pains me to see all the heat disappear up the stack though. I will, eventually build a little rumford in this corner... but i think thats a spring job.

Enjoying the experimentation, but still more questions than contributions. All the best.

[Donkey]

Last thing first... The dangers of installing dampers exist in ANY position you care to put them in.
if there is stuff that should be going outside, going inside instead.. You may have a problem.

Sure, the damper WILL keep heat inside the home and you will always remember how to use it properly. However...


Yeah.. the 8 inch systems can be impressive...
My opinion, go six inch. its far easier to find parts. While you should have some instant radiant (only you can say how much), build with lots of thermal mass. Soak up all the heat that the 6 inch system can provide. If you see steam coming out the pipe youve done well. You will experience some condensation inside piping, so either dial slightly hotter (remove thermal mass) or provide for drainage (and possible use) of wood vinegar. Keeping the stovepipe inside can actually be helpful, just try to reserve all the heat you need first.

Im not picturing Kikos diagram right now, so forgive.

The key is to experiment as you build. Lay the whole thing out, test, adjust, test, repeat.
Run the stove in place AS YOU BUILD. You will know INSTANTLY if a passage gets blocked and when there is enough thermal mass and if the cleanouts are in a clever place or if the drains are working and why not... Wet materials tend to sap a whole lot more heat from the system than dry so if the stove runs like a champ wet, it will dry too.
Its also just fun to cob on to a hot stove, steam flying, warm hands. Dirty but fun.
... Just be thoughtful, it can be somewhat dangerous.

[canyon]

I'm sorry but what is a bothy? Also, I'm unsure about what your'e unsure about in capping at the top?
I'm curious about the 4"... I almost built one this fall for a hot water heater (I ran out of time before the snow flew). Why not? Go for it and share the experience! A 4" seems to me like a good size for a small yurt and slender wood.
A Rumford in a Yurt??!
Whoa ho ho! What a trip!
Hey Donkey, would you elaborate on wood vinegar?

[Donkey]

Umm.. From dict.die.net

wood vinegar
n : a red-brown liquid formed in distillation of wood which
contains acetic acid, methanol, acetone, wood oils, and
tars [syn: pyroligneous acid]

Actually, scratch that.. If your rocket stove is working properly you should NOT be getting wood vinegar, you should be burning that stuff off and saving the heat.. My bad.

[gealbhan]

Nov 19, 2007 17:09:39 GMT -8 rhyddid said:

Well the yurts up, floating on a rubble trench and some bolted tires, tied down with some serious storm ropesto resist these northerly winds and nicely insulated.

Built a 8inch system in the wood outside with firebrick after finding a large heat riser as an offcut at a friends building yard. My god it roars! Almost as much as the appreciation from the wealth of poeple who have popped by to have a peep.
Problem... its huge! I will relocate this system to a bothy i work at.

So, need to scale down. My question is how small. Considering a 4 inch system with a smaller burn tunnel. Has anyone tried goiing this small before?

Having loooked at KikoDenzers diagram in the mass heater book. Im considering something like this, with the Heat Exchanger built out of fire-brick. Unsure how to cap it at the top though.

Then, mostly to save space, i thought of sending the stove straight up from the bottom of the heat exchanger through the center of the yurt. (a good 106 inches) with some newly acquired titanium stove pipe and a silicone insert to sew into the fabric.

Also thought of insulating the stack somewhat, but unsure, as you say, of the trade off between radiant and stored heat.

Still have some large pieces of galvanised ducting from the large version. Which could encase the stovepipe and be filled with insulant.

Another somewhat contraversial question... I know its been made pretty clear of the dangers of installing a damper in a horizontal system. However, in a vertical system... once the combustion is complete and the burn chamber closed. Do you see any merit in having a damper near the top of the stack to stop the heat rising up and out?

In the meantime, Ive put in a small woodstove near the wall, which reduces the stakes somewhat by ensuring some heat for my partner! It pains me to see all the heat disappear up the stack though. I will, eventually build a little rumford in this corner... but i think thats a spring job.

Enjoying the experimentation, but still more questions than contributions. All the best.

Och, ye couldnae be that far in the north could ye? I'm in Scotland too. Caithness actually. I had the same idea. doing a rocket stove in a yurt. wis gonnae build a foundation for a normal cob roondhoose with a cob floor and furniture on the inside, plus the rocket stove through a bench and dipping down through the earthen floor and oot again.. Didna get roond to it tho. I jus huv it pitched up on e earthen platform. Been living in there fur aboot 9 month noo. and you? Would love to see any photos ye've got of yer set up. If ye get any further wi yer rocket. gis us a shout.