Satamax Antone wrote:Jeremiah, i'll say it again, build yourself one. Then you'll see for yourself. There is no magic behind RMH. And you can make one for free or pretty much.
God of procrastination https://www.youtube.com/watch?v=q1EoT9sedqY
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Rich Pasto wrote:"you believing it is not a requirement for it being true." - US Army
they work.
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//BT//
August Brooks wrote:In our tests, our stove will burn about 1/2 cubic foot of wood in 2 hours. That's roughly 15 pounds of wood. If one pound of wood gives off 8600 BTU's, then the total BTU's produced by 15 pounds of wood is approximately 129,000 BTU's in 2 hours. Take into consideration the wasted heat from the exhaust which was 130 degrees F, (for demonstration purposes) we'll call it 10% BTU loss. That means that our stove alone (without a thermal mass), is giving off 116,100 BTU's over 2 hours.
Now, when adding a thermal mass to this equation, the heat loss goes down considerably and the total BTU's utilized is a much higher percentage of total heat produced. Conventional wood stoves can't even come close to this percentage because they send most of their BTU's out the exhaust.
August Brooks wrote:(E). Due to the hot rock and second burn you will actually use less wood ex. 1 cord vs 8 cord
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allen lumley wrote: Frank R.: While there are stoves that can be run nearly as efficiently as a rocket stove, and new ones being ''rushed to market'', the new owner soon teaches themselves
how to 'load that dirty bastard up.' ' to let it burn all the day without taking up any more of my time ' ! ! i.e. burning dirty and inefficiently, like my neighbors ! The worst
ones are the ones that deliver domestic hot water, they smolder along 24-7, 52 weeks of the year to guarantee a hot shower at will 24-7, 52 weeks of the year !
I will make a General statement that while the Rocket Stove has a major draw back, that it needs frequent attention to run at its most efficient, that this is the only way
that the Rocket Stove can be run! This is also its biggest asset, forcing you to burn it in its most efficient manner, or get smoked out of house, or left with a cold house !
Living with a Rocket Stove and its hungry Dragon is a life style commitment! If you are not willing to live this way, the Rocket Stove is not for you! If someone has to be
'out of the house' to be 'the Bread Winner', then they most spend 6-8 hrs prepared to and attending on their Rocket Stove To get 20-25 hrs of heat stored inside their
Thermal Battery,or have a Partner willing to assume that job ,or deal with a cold house !
Success has a Thousand Fathers , Failure is an Orphan
LOOK AT THE " SIMILAR THREADS " BELOW !
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Success has a Thousand Fathers , Failure is an Orphan
LOOK AT THE " SIMILAR THREADS " BELOW !
paul wheaton wrote:A rocket stove is for cooking outdoors.
A rocket mass heater is used for heating your home.
paul wheaton wrote:The math on how they are so much more efficient is spelled out at http://www.richsoil.com/rocket-stove-mass-heater.jsp
The great thing about a rocket mass heater is that not only does it heat your home with 1/10th of the wood, but it requires far less fooling with than a conventional wood stove. If nothing else, you have 1/10th the wood to fool with. But even better is that you can burn a fast hot fire in the evening and then you're done. The house stays warm through the night with no further fire. You wake up in the morning and the house is warm - no need to start a morning fire.
Keep in mind that a rocket mass heater leans heavily on radiant heat and conductive heat - which are both far more efficient than convective heat. Also keep in mind that most people run their conventional wood stoves in a way to try to make the fire last longer. So while their stove might be rated as 75% efficient, they might be getting only 10% efficiency. Or worse.
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For the many not for the few
http://www.permies.com/t/80/31583/projects/Permie-Pennies-France#330873
that it is not an apples to apples comparison
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Frank Rasmussen wrote:Geo,
Thanks for your comment. I've read your web page and a few of your posts and it seems that you have had a similar idea to me. One of the first things that occurred to me when thinking about RMH technology was to create a water heater, storage and radiator system as you have done. Well done on your implementation.
I keep thinking of how to make the system safer, e.g. by making an insulated fire box rather than using a feed tube. Obviously if you do that, you have to incorporate some secondary air into the system for secondary combustion. This system then starts to look a lot like the EPA non-catalytic stoves, since they have somewhat insulated fireboxes and preheated secondary air.
calen kennett wrote:I'm working on a video about building these stoves and the stove we build heats a 3,000+ sf home with 3 stories. It is the exclusive source of heat for the house. I have spent a couple of months in the house at different times of the year since we built the stove a couple years back and I tell you, it is awesome! Everyone comments on it and everyone wants to sit on it when its hot. It has been their exclusive source of heat for a couple years and they still remark about how much they love it. They do crank it up for a couple hours in the evening to keep the house warm overnight, but it does work, and it works really well. I've seen it.
Frank Rasmussen wrote:
August Brooks wrote:In our tests, our stove will burn about 1/2 cubic foot of wood in 2 hours. That's roughly 15 pounds of wood. If one pound of wood gives off 8600 BTU's, then the total BTU's produced by 15 pounds of wood is approximately 129,000 BTU's in 2 hours. Take into consideration the wasted heat from the exhaust which was 130 degrees F, (for demonstration purposes) we'll call it 10% BTU loss. That means that our stove alone (without a thermal mass), is giving off 116,100 BTU's over 2 hours.
Now, when adding a thermal mass to this equation, the heat loss goes down considerably and the total BTU's utilized is a much higher percentage of total heat produced. Conventional wood stoves can't even come close to this percentage because they send most of their BTU's out the exhaust.
I want to believe. However, let's do the math. A BTU is roughly a kJ. You say that 1lbs of wood gives 8600BTUs. This may be the case in oven dry wood, so I'll give that to you, even though it's unrealistic in air dried wood. This 8600BTU figure is about as good as you could possibly get, as far as I can tell. Any more
I'll convert that figure to SI units, as that's what I'm familiar with. 1lbs of wood = 8600BTUs = 9073kJ. 15 pounds is 129,000BTU = 136,102kJ. If this is supposed to heat a house for 24 hours, we can work out the average power. P(average) = W/T = 136,102/(24*3600) = 1.57kJ/s = 1.57kW. Now 1.57kW is a fairly pitiful amount of power.
I've seen some estimates of daily wood requirements for other rocket stoves. For example, 35lbs/day in the worst of winter, a winter that gets to well below freezing. That equates to 3.6kW. That is still not a lot of heat unless your house is very well insulated. For example, my house has some insulation in the roof but none in the walls. It is 1200 square feet in area. Our heat pump's maximum heat output is 8.5kW. On a night that was no colder than 8 degrees Celsius, (46F) this heat pump was working its hardest and was heating the house barely adequately if the doors to the kitchen and dining room were open as well. Presumably with a rocket stove the heating would have either been insufficient or we would have had to use more wood.
August Brooks wrote:(E). Due to the hot rock and second burn you will actually use less wood ex. 1 cord vs 8 cord
It is specifically this that I am dubious about. Now, I absolutely hate smoke from wood fires, I hate that it causes asthma, and I hate that in areas that do not have sufficient government regulation the whole of a region must suffer because of the selfishness of those who pollute the neighbourhood. However, there are relatively clean commercial stoves out there these days and I'm finding it hard to reconcile the claims of using 1/5 the wood as one of these (being generous), all else being equal. Does anyone care to comment?
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Rocket Mass Heater Jamboree And Updates
https://permies.com/t/170234/Rocket-Mass-Heater-Jamboree-Updates
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