However, I have considered getting one of those cheapy wood stoves and converting it to an outdoor rocket stove.
The best thing you can do to make a regular wood stove more efficient is to build a thermal-mass wall around it (and add a grate inside to keep air flowing beneath the logs). If the floor is an on-grade slab it should be no problem, but if it is above a basement or another floor you will have to reinforce the joists below to carry the weight. A 4 ft. high 8" thick brick wall on each side should absorb a lot of the heat and keep it in the house for a good 12-24 hours after the fire goes out. We have an efficient Jotul insert inside an old brick fireplace that is 8” at the interior face, much thicker outside, and the bricks inside are still warm 24 hours after the stove itself is cool enough to put bare hands inside.
Sugar Mountain Farm
in the mountains of Vermont
however a RMH is supposed to put out little to no smoke. ours puts out CO2 and steam for most of the burn. about the first 6 min it puts out a little smoke. this equates to me bringing in a single arm load of wood a week (it seldom gets below zero here so i would assume you might bring in two or three armload's of wood). All in all i burn a quarter cord of wood to my folks next doors 3 cords. typical here is 5 cord a winter. Each to there own.
Ernie Wisner wrote:All in all i burn a quarter cord of wood to my folks next doors 3 cords. typical here is 5 cord a winter.
We burn a little less than 0.75 cord of wood a year. This is our heat source. It puts out almost no smoke. Same principles as the rocket stove with the way we set it up. The mass was the key to capturing the quick burn.
Hi there, I've got a wood stove with a hydronic heat exchanger running through it that pre-heats all my house hold hot water. Thus greatly reducing the bills in the winter, or if you live were I do in the fall and early spring too. The stove also has a thermal mass chimney that stores and holds the heat. I'll post some pictures and be happy to answer any questions that arise.
So, the chimney goes up through that cinderblock column, right? Is the metal of the chimney right up against the block, or is there filler in there as well?
I see two pipes going into the stove and then back through the wall - can you go into more detail about the heat exchanger, how water gets from point A to B, and how you deal with pressure building up in the system?
Some friends of mine were considering a similar approach with their woodstove; I'd appreciate hearing about your build process, what worked, what didn't, and what, if anything, you'd change or do differently.
2nd. The fire place. Without a picture I can't really tell you what to do. Generally installing metal pipe up a chimney is a pain in the butt and doesn't do any thing for an open fire place, part of a good fire place design is the smoke shelf, which insures proper ventilation, putting a pipe in wont help this. Depending on the shape of your fire box, you may be able to retro-fit with fire brick to turn it into a Rumford fireplace. I will let you do your own research on Rumfords but they are super efficient, giving off more radiant heat and less exhaust than a typical fireplace.
He calls it a hat.
Thanks, that was very interesting about the "hat".
There are often different ways of doing the same kinds of things. Both RMHs and masonry stoves try to do the same thing... burn fast and clean, but use mass to store the heat for later and keep the room from being to hot. In general, the two worlds don't interact too much. I find I learn more by following both worlds. I got that link from the MHA news letter (blog? whatever).
The thermal mass of the stone has 'dampened' the temperature swings inside the house by over 12F (cooler in summer, warmer in winter) without ever lighting up the fireplace! I also positioned (part of the initial design) the fireplace in the center of the house and also allows winter (lo angle) sun to hit it for 6+ hours each winter toward the SW setting sun.... so it really is a Trombe wall.
I 'stoned-in' a small fire stove next to the fireplace which i keep fired up most of the time as a kinda slow burn... to heat water and cook... and also keeps the temp of the rock wall going at night or cloudy days.
If i had known about RMH's 10 years ago, when I designed this, I would've done the whole thing totally differently. I'm still looking for ways to retrofit it, but it may just be beyond that... way too much stone I would have to move.
I am hopeful that some cool ideas will come from this forum, or my own playing around with various configurations of RMH's to retrofit my 'fireplace'. What really give me pause tho, is the carbon monoxide potential of enclosed RMHs.