Hi Ronnn,
I spotted that another commenter had linked to my site on wood burning stoves and mentioned rocket stoves as a possibility. I hope you don't mind me joining and adding some thought of my own!
If you have the scope to build a large thermal mass structure from scratch in your home then these are a fantastic option, especially in an adobe structure as you describe. Sadly I don't think I'd get away with one in my 14C first floor flat, otherwise I'd be building one myself right now rather than sitting here typing.
Rocket stoves are really well optimised:
- The burn is fast and complete, with plenty of intake air
- The heat riser design ensures sufficient draft to the fire, even with a convoluted flue
- The convoluted flu, ducted through a large mass of cob, extracts the maximal amount of heat possible from your exhaust gases
- The heat is released gently into the room - no massive swings in temperature between when the stove is lit and not
As far as optimising your existing situation goes there are a few things you could do. As you say, burning with the inlet air shut right down slows the fire, but it also makes it very polluting, sending a significant amount of smoke (unburnt fuel!) up the chimney. For both environmental and efficiency reasons I would suggest burning with more inlet air available and/or providing secondary air.
Your second issue appears to be with heat distribution within your home - you mention a passive convection principal which sounds really interesting. One issue that we have had with our wood stoves is that there is only a limited distance from the stove where it is comfortable to sit. If you are too close you overheat, and if you are too far way the cool air drawn towards the stove will chill your back, feet etc... (you mention a river of air - we get the same in my parents large home).
Directing external directly to the firebox will help reduce the cold air flowing in and chilling the living space. This doesn't need to be plumbed in to the stove directly, a simple open ended pipe resting within a few inches of the stove air inlet will help substantially.
To distribute the heat further still from the stove you should consider a getting a stove fan, such as the Airplus Ecofan 802. We have used fans similar to this for a number of years and they make a substantial difference to how far the heat from your stove can be distributed - some estimates are that they can improve stove efficiency by around 30%. I know that qualitatively the room "feels" warmer with one of these fans running, and the warm air spreads further through the whole house as a result.
If you can improve warm air distribution to the more remote parts of your home I suspect that you would find more of your thermal mass kicking in to play - the warm air will spread further and contact more of the wall and floor surfaces than at present - so you will improve long term heat storage as well.
key points
- run your stove with more air
- get a stove top fan to improve efficiency of heat distribution from your stove to the space
I suggest trying both of these points first and then seeing if you notice an improvement - you may find less wood is needed to heat the further parts of your home.
Long term - consider upgrading to a rocket stove. With some drive and time they can be built in a few days for under £100.
Please do let me know how this works out for you!
Mike