I have seen the tipi - I can vouch for it. It's just a canvas wrap around poles, open at the top, open along the ground. And yet, with the heat of a rocket mass heater, you can be comfy in there when it's bitterly cold outside.
I have been working towards this method for 5 years,first I just put bricks, maybe 100 ,around a small wood stove. Instantly I could see a difference the next morning in the temp. Then I wanted to make a nice garden and used the bricks to edge the garden. The next winter was much colder in the house in the morning. This year I added 1000 free bricks around the stove and it is much warmer in the morning. Anyone who thinks heating a mass with the same amount of wood is the wrong way to go is 100% wrong. How you distribute the heat is up to you. I have the bricks on top and surrounding the stove , a fan on a timer to blow the warm air from the basement ,where the stove is , up through 3- 5 inch ducts so the house is divided in 3 sections . Heating a 5k sq ft area so hot we leave a window open at night in the bedroom. 4 months into this year and haven't used 1/4 a cord of wood yet. I am not convinced on the rocket stove being better than a conventional stove , however you probably already know I am building one by commenting and watching. I plan to build it separate from the stove I have and test them side by side over time.
Really great discussion! Yeah, that mass heat really works, it is tricky to adjust to sometimes though, like when the morning is cold and you want to light a fire, but the days are warm, because it will be too hot. There is a time delay in the heat release. It is certainly a better way to go, but my parents have spent a year adjusting to the cadence of firing their masonry heater here in Canada. One thing that I didn't hear you mention here is that with mass heaters, the heat comes from below while with air heating you will get the heat to rise, giving a hot head and cold feet. Also that point about burning less wood is huge! Not only do you save on fuel work and cost, but the amount of air that needs to be sucked in through the holes is far less and so there is way less draft. I have improved my box stove by bringing outdoor in right to the stove, it makes less draft in the rest of the house. I am planning to build a rocket stove soon though, you have really helped to inspire me, thanks!
A kotatsu (炬燵) is a low, wooden table frame covered by a futon, or heavy blanket, upon which a table top sits. Underneath is a heat source, formerly a charcoal brazier but now electric, often built into the table itself. Kotatsu are used almost exclusively in Japan, although similar devices are used elsewhere: for example the Spanish brasero or Iranian korsi. en.wikipedia.org/wiki/Kotatsu
paul wheaton - here's a prime example... My GF who is ALWAYS cold, sits on the porch to smoke, and was using a "glowing flat wire element with a reflector behind it and a junky little fan" type electric heater, burning 1500 watts, and mostly heating air that never even made it the foot and a half from where it sat facing her on the table. Generally it was warming only her hands that actually were held close enough to it. I'm guessing probably only 10-15% of the heat coming from it was radiant. I took ONE 250 watt heat lamp and mounted it the same distance from her, in a ceramic outlet rigged to sit on a base on top of the table, and she was instantly warmer over her ENTIRE side facing the heat lamp, than that 1500 watt heater chugging away ever got her. When I installed the second one in a brooder lamp shining down on her head and neck from above and behind her, I became her radiant heat HERO, and have been saving 10 cents an hour (2/3) while she is MORE comfortable than before. (And it's all thanks to what I've learned from you and the other innovators) Next step is to build a small "radiant rocket" and stop paying the power company at all to be warm on the porch... Just have to go out in the yard and play pick up sticks to earn our heated porch time.
I'm using an old crappy wood stove that is not very efficient. I have 4 stacks (2 on each side) of 5 gallon pails full of water stacked 3 high (total of 12 buckets) arranged around it that absorb the radiant heat from the stove. It makes a huge difference in keeping the house warm. When the fire in the stove goes out at night I don't wake up freezing like I did before I put the water around the stove.
R-value is ONLY a measure of how badly heat bleeds through a structure... It cannot be used to quantify the heat storage, and resistance to change in temperature, of high mass wall structures.
Great information on so many things. Thank you. Could one build a rocket heater making the fire tube, combustion chamber, and tube inside the drum using sono-tubes and perlite with water glass? Your thoughts please. Thanks. Keep up the good work. Really appreciate you!
If you could design a house from scratch, how would you design the room for that initial smoke from the startup? Seems like the teepee is nice because it has the hole at the top, but what about a convential room. Do you just open a window and blow the smoke out with a fan?
aletoledo1 - these innovators designing these systems have generally found ways to eliminate smoke back on startup. A good tall, insulated chimney, preferably out the roof, is a large factor for good initial draw, and where smoke back still occurs, a "bypass" is used, that sends gasses directly from the "barrel" up the chimney until the chimney and combustion section of the stove have heated enough to generate their own draw. Highly insulative, lightweight materials for the "hot-faces" of the combustion section are a key factor to a good performing stove as well. Systems have been designed and built that really have no smoke back issues at all, though some may be available as plans that the innovator (rightly) sells for a reasonable price, but you can certainly use the info available for free to learn enough to make, possibly with a bit of trial and error, your own, successful, smoke-back free design... If you pay a little you can get a proven set of plans. The core design, the heat collection area, and the chimney are ALL factors in a smoke free stove. All have some wiggle room, and bounds of functionality, with some performance factors dependent on design choices in the other parts. If you design the stove well, the design of the house will not matter as much. As with any combustion appliance including wood stoves, negative air pressure from large exhaust fans could effect performance toward having smoke-back/improper exhaust, and a house that is TOO well air-sealed could cause issues with draw, but that is relatively rare, and the easy solution is to crack a window in the room where the heater is...
then you do NOT know how to start a 'smokeless fire', or have wet wood, or, the unit is not built correctly. ALL wood-fired devices/units, should..."'should''..already have a natural, positive draft, or, provision/s to start it in the 'exhaust' phase, next to the chimney.
Novo Karpati - true... Some rockets, especially j style have a tendency to smoke back until they get warm, but bypasses and other design improvements have effectively eliminated that problem when the proper design improvements were made... It was most often a problem for people who had short chimneys that exited out the side of the house... Usually chosen by people who didn't want to figure out how to deal a new penetration through an existing roof... Also less likely to be a problem when a low mass highly insulative refractory is used in the combustion core areas.
Smoke back on startup is usually only a problem when the system is "cold started." Meaning when the thermal mass is cold and no natural draft is present, usually it only happens on the first burn of the season. It also happens on poorly designed systems which is what the Erica and Ernie, and many others, have been testing and teaching for years.
So, I don't recall anyone, in these videos, actually Testing, via Combustion Sampling Technology, any of the devices mentioned. Or, did I miss that part..?
I know that I have never done that. I have no idea if anybody else has. I know that peter, ernie, erica and donkey have a lot of testing equipment, but I don't know what all they have. For me, I am amazed at how little wood I use to heat my house. And I see the tiny dribble of steam coming out of the exhaust. I feel good. I think that if there are other angles of testing you wish to see, and by checking with other folks turns up that they have not done the tests you seek, then it may be up to you to do that testing. In the meantime, other folks will be like me: the body of evidence is quite satisfactory.
Here is some data... 12 hours after they burned a fire for 3-4 hours, 4000lbs of thermal mass is still warmer than the cheeks seated upon it... ;-) My "80% efficient EPA rating" wood stove doesn't do that... Heats mostly the air in my house, and sends 350-600F gasses up the flue, to prevent creosote build up from that other 20%, and to keep air being sucked in at the proper rate. At the same time it sends a large stream of smoke and creosote constituents into the environment. Testo data for the combustion efficiency of Peter's batch rocket design from his batchrocket.eu site is available and the design is open source, so you are free to build one. Overall system efficiency is determined by what you put behind it to collect the heat and release it over time, and how hot the exiting flue gasses after your heat capture system are. These people are generally self funded in their research and perfectly willing to use objective data like "before we burned 3-4 cords of wood a winter to stay warm during the day and woke up to a 45F house... We built a rocket mass heater, burn one 3-4 hour cycle a day spring and fall, and two in winter, and are consistently warm, and the house remains at 65 when we wake up in the morning. We made NO other changes to the house's insulation or other factors that would effect it's heat retention. Just replaced the wood stove with the rocket mass heater, are MORE comfortable 24/7, and we do it with 1/4 (for some as little as 1/10th) the wood."
But if you have the sensors and data logging equipment to take these designs and conduct such data collection it would be a valuable addition to this open source community. Also, be aware that 80-90% of people with "rocket mass heater" videos on UA-cam are building designs that miss very basic features of the innovations that these people have pioneered. If it has metal in the interior "flame path" area of the stove, and that metal is not scaling away or melting out entirely within a few burns, the design is not achieving the type of high heat, high efficiency combustion these pioneers are producing in their designs. The best places to find info and advice, should you choose to join the open source project; Paul Wheaton's permaculture forum rocket stoves and rocket mass heaters sections and his videos and interviews about them here on UA-cam. Kurt (Donkey's) rocket stove forum on pro-boards Peter's Batchrocket.eu site All video's featuring Ernie and Erica Wisner here on UA-cam, and their Ernieanderica.info site. All that stuff is free^^^ For pay informational products I can think of off the top of my head include: Ianto Evan's & Leslie Jackson's Rocket Mass Heaters book, various books and stove designs by Ernie and Erica, as well as the multiple videos for sale on rocket stoves and fire science through permies.com... But you can learn enough to build your own and start testing, just from the free resources above.
Interesting stuff on wood consumption, how many BTUs from how much wood? Seat of the pants, it produces heat to be comfortable to sit on. Hows the temp of the air in the house vs outside? There is little info on testing of the stoves, no one has paid a testing lab for it. Some colleges have run development tests, some not for profits too. They are mainly looking at developing country cooking stoves.
thanks to my patreon peeps for getting my youtube engine running again patreon.com/pwvids
I have seen the tipi - I can vouch for it. It's just a canvas wrap around poles, open at the top, open along the ground. And yet, with the heat of a rocket mass heater, you can be comfy in there when it's bitterly cold outside.
I have been working towards this method for 5 years,first I just put bricks, maybe 100 ,around a small wood stove. Instantly I could see a difference the next morning in the temp. Then I wanted to make a nice garden and used the bricks to edge the garden. The next winter was much colder in the house in the morning.
This year I added 1000 free bricks around the stove and it is much warmer in the morning. Anyone who thinks heating a mass with the same amount of wood is the wrong way to go is 100% wrong. How you distribute the heat is up to you.
I have the bricks on top and surrounding the stove , a fan on a timer to blow the warm air from the basement ,where the stove is , up through 3- 5 inch ducts so the house is divided in 3 sections . Heating a 5k sq ft area so hot we leave a window open at night in the bedroom. 4 months into this year and haven't used 1/4 a cord of wood yet.
I am not convinced on the rocket stove being better than a conventional stove , however you probably already know I am building one by commenting and watching. I plan to build it separate from the stove I have and test them side by side over time.
Really great discussion!
Yeah, that mass heat really works, it is tricky to adjust to sometimes though, like when the morning is cold and you want to light a fire, but the days are warm, because it will be too hot. There is a time delay in the heat release. It is certainly a better way to go, but my parents have spent a year adjusting to the cadence of firing their masonry heater here in Canada.
One thing that I didn't hear you mention here is that with mass heaters, the heat comes from below while with air heating you will get the heat to rise, giving a hot head and cold feet.
Also that point about burning less wood is huge! Not only do you save on fuel work and cost, but the amount of air that needs to be sucked in through the holes is far less and so there is way less draft. I have improved my box stove by bringing outdoor in right to the stove, it makes less draft in the rest of the house.
I am planning to build a rocket stove soon though, you have really helped to inspire me, thanks!
A kotatsu (炬燵) is a low, wooden table frame covered by a futon, or heavy blanket, upon which a table top sits. Underneath is a heat source, formerly a charcoal brazier but now electric, often built into the table itself. Kotatsu are used almost exclusively in Japan, although similar devices are used elsewhere: for example the Spanish brasero or Iranian korsi. en.wikipedia.org/wiki/Kotatsu
The key is what donkey said: there is a huge amount of power and efficiency with radiant and conductive heat.
paul wheaton - here's a prime example...
My GF who is ALWAYS cold, sits on the porch to smoke, and was using a "glowing flat wire element with a reflector behind it and a junky little fan" type electric heater, burning 1500 watts, and mostly heating air that never even made it the foot and a half from where it sat facing her on the table. Generally it was warming only her hands that actually were held close enough to it. I'm guessing probably only 10-15% of the heat coming from it was radiant.
I took ONE 250 watt heat lamp and mounted it the same distance from her, in a ceramic outlet rigged to sit on a base on top of the table, and she was instantly warmer over her ENTIRE side facing the heat lamp, than that 1500 watt heater chugging away ever got her.
When I installed the second one in a brooder lamp shining down on her head and neck from above and behind her, I became her radiant heat HERO, and have been saving 10 cents an hour (2/3) while she is MORE comfortable than before. (And it's all thanks to what I've learned from you and the other innovators)
Next step is to build a small "radiant rocket" and stop paying the power company at all to be warm on the porch...
Just have to go out in the yard and play pick up sticks to earn our heated porch time.
the amazing efficiency of radiant heat!
orcoastgreenman or you could get her to stop smoking... lol
Fred Garvin - It will happen sooner or later. I hear heroin is easier to quit, so we're going to switch, and then quit that.
orcoastgreenman lol. no offense was meant btw. glad you didnt think i was judging. good luck to ya and great idea with the heat bulbs.
I'm using an old crappy wood stove that is not very efficient. I have 4 stacks (2 on each side) of 5 gallon pails full of water stacked 3 high (total of 12 buckets) arranged around it that absorb the radiant heat from the stove. It makes a huge difference in keeping the house warm. When the fire in the stove goes out at night I don't wake up freezing like I did before I put the water around the stove.
R-value is ONLY a measure of how badly heat bleeds through a structure... It cannot be used to quantify the heat storage, and resistance to change in temperature, of high mass wall structures.
Great information on so many things. Thank you. Could one build a rocket heater making the fire tube, combustion chamber, and tube inside the drum using sono-tubes and perlite with water glass? Your thoughts please. Thanks. Keep up the good work. Really appreciate you!
So you should have the air going into the building go in through the mass of your RMH so it gets heated directly.
great points made!
If you could design a house from scratch, how would you design the room for that initial smoke from the startup? Seems like the teepee is nice because it has the hole at the top, but what about a convential room. Do you just open a window and blow the smoke out with a fan?
aletoledo1 - these innovators designing these systems have generally found ways to eliminate smoke back on startup.
A good tall, insulated chimney, preferably out the roof, is a large factor for good initial draw, and where smoke back still occurs, a "bypass" is used, that sends gasses directly from the "barrel" up the chimney until the chimney and combustion section of the stove have heated enough to generate their own draw.
Highly insulative, lightweight materials for the "hot-faces" of the combustion section are a key factor to a good performing stove as well.
Systems have been designed and built that really have no smoke back issues at all, though some may be available as plans that the innovator (rightly) sells for a reasonable price, but you can certainly use the info available for free to learn enough to make, possibly with a bit of trial and error, your own, successful, smoke-back free design... If you pay a little you can get a proven set of plans.
The core design, the heat collection area, and the chimney are ALL factors in a smoke free stove. All have some wiggle room, and bounds of functionality, with some performance factors dependent on design choices in the other parts.
If you design the stove well, the design of the house will not matter as much.
As with any combustion appliance including wood stoves, negative air pressure from large exhaust fans could effect performance toward having smoke-back/improper exhaust, and a house that is TOO well air-sealed could cause issues with draw, but that is relatively rare, and the easy solution is to crack a window in the room where the heater is...
then you do NOT know how to start a 'smokeless fire', or have wet wood, or, the unit is not built correctly. ALL wood-fired devices/units, should..."'should''..already have a natural, positive draft, or, provision/s to start it in the 'exhaust' phase, next to the chimney.
Novo Karpati - true... Some rockets, especially j style have a tendency to smoke back until they get warm, but bypasses and other design improvements have effectively eliminated that problem when the proper design improvements were made...
It was most often a problem for people who had short chimneys that exited out the side of the house... Usually chosen by people who didn't want to figure out how to deal a new penetration through an existing roof...
Also less likely to be a problem when a low mass highly insulative refractory is used in the combustion core areas.
Smoke back on startup is usually only a problem when the system is "cold started." Meaning when the thermal mass is cold and no natural draft is present, usually it only happens on the first burn of the season. It also happens on poorly designed systems which is what the Erica and Ernie, and many others, have been testing and teaching for years.
So, I don't recall anyone, in these videos, actually Testing, via Combustion Sampling Technology, any of the devices mentioned. Or, did I miss that part..?
I know that I have never done that. I have no idea if anybody else has. I know that peter, ernie, erica and donkey have a lot of testing equipment, but I don't know what all they have.
For me, I am amazed at how little wood I use to heat my house. And I see the tiny dribble of steam coming out of the exhaust. I feel good.
I think that if there are other angles of testing you wish to see, and by checking with other folks turns up that they have not done the tests you seek, then it may be up to you to do that testing. In the meantime, other folks will be like me: the body of evidence is quite satisfactory.
I’m going to build a rocket mass heater batch box with a bench big enough to double as a king size bed.
I just spotted the dog!
I will ask what every engineer asks, where is the data? Time, temp and humidity.
Here is some data... 12 hours after they burned a fire for 3-4 hours, 4000lbs of thermal mass is still warmer than the cheeks seated upon it... ;-)
My "80% efficient EPA rating" wood stove doesn't do that... Heats mostly the air in my house, and sends 350-600F gasses up the flue, to prevent creosote build up from that other 20%, and to keep air being sucked in at the proper rate. At the same time it sends a large stream of smoke and creosote constituents into the environment.
Testo data for the combustion efficiency of Peter's batch rocket design from his batchrocket.eu site is available and the design is open source, so you are free to build one.
Overall system efficiency is determined by what you put behind it to collect the heat and release it over time, and how hot the exiting flue gasses after your heat capture system are.
These people are generally self funded in their research and perfectly willing to use objective data like "before we burned 3-4 cords of wood a winter to stay warm during the day and woke up to a 45F house... We built a rocket mass heater, burn one 3-4 hour cycle a day spring and fall, and two in winter, and are consistently warm, and the house remains at 65 when we wake up in the morning. We made NO other changes to the house's insulation or other factors that would effect it's heat retention. Just replaced the wood stove with the rocket mass heater, are MORE comfortable 24/7, and we do it with 1/4 (for some as little as 1/10th) the wood."
But if you have the sensors and data logging equipment to take these designs and conduct such data collection it would be a valuable addition to this open source community.
Also, be aware that 80-90% of people with "rocket mass heater" videos on UA-cam are building designs that miss very basic features of the innovations that these people have pioneered.
If it has metal in the interior "flame path" area of the stove, and that metal is not scaling away or melting out entirely within a few burns, the design is not achieving the type of high heat, high efficiency combustion these pioneers are producing in their designs.
The best places to find info and advice, should you choose to join the open source project;
Paul Wheaton's permaculture forum rocket stoves and rocket mass heaters sections and his videos and interviews about them here on UA-cam.
Kurt (Donkey's) rocket stove forum on pro-boards
Peter's Batchrocket.eu site
All video's featuring Ernie and Erica Wisner here on UA-cam, and their Ernieanderica.info site.
All that stuff is free^^^
For pay informational products I can think of off the top of my head include:
Ianto Evan's & Leslie Jackson's Rocket Mass Heaters book, various books and stove designs by Ernie and Erica, as well as the multiple videos for sale on rocket stoves and fire science through permies.com... But you can learn enough to build your own and start testing, just from the free resources above.
Interesting stuff on wood consumption, how many BTUs from how much wood? Seat of the pants, it produces heat to be comfortable to sit on.
Hows the temp of the air in the house vs outside?
There is little info on testing of the stoves, no one has paid a testing lab for it. Some colleges have run development tests, some not for profits too. They are mainly looking at developing country cooking stoves.