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efficient rocket stove dimentions  RSS feed

 
Glen Cox
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I am very new to this and I am glad to be here.
What I am looking for is information on rocket stoves.

I would like to know if there are optimum dimensions and ratios in building a rocket stove?
I am looking for two things here, the best and most complete burn of my fuel (wood) and the best use of the heat energy for cooking.
I have seen many youtube videos that show short rocket stoves and it seems most, if not all commercially made stoves are short.
What I have noticed though is that there quite often is a lot of flame escaping from the top of the stove and licking around the pot, pan or pale.
It seems to me that there is a loss of efficiency and heat when this happens. I would think that making a longer (taller) chimmeny would put the
cooking surface closer to the tip of the flame where the highest heat of the flame is located. Am I correct in this assumption? Then if I wanted a
lower heat for slower cooking Couldn't I just regulate my airflow?
 
R Scott
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Location: Kansas Zone 6a
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Rocket COOK stove, you are right. But everything is a tradeoff.

To make the riser tall enough for a complete burn (no charring the pot), you either need to build the feedtube into the floor or stand on a ladder to reach the pot. Too tall doesn't ship or store well, and is quite tippy--VERY unsafe with kids around. Too tall also sucks more heat out into the riser and less goes into the pot. It also mimics the height of the simple rock stoves they were meant to replace.

The fact the riser needs to be 3 times taller than the feedtube on a J and it becomes very limiting as to size and design. That is a big part of the reason most cookstoves are the approvecha L tube style. The other part is it allows some fine tuning of heat by moving the sticks in and out of the tube. You don't want to regulate air, you want to limit fuel to limit heat.

Every portable design I have seen is built around ergonomics FIRST and then adjusts the burn tunnel size to work "good enough" across a wide range of fuel.

I have built my own, I have bought a couple. I will be building a new hybrid for my outdoor kitchen--using a commercial burner plus build a windscreen/cooktop to go around it.
 
Bob Jackson
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You're right; all that soot on the pans is wasted fuel, but may still be the most efficient way. One place I found with a lot of info:

http://www.aprovecho.org/lab/rad/rl/stove-design/category/1
Specifically link #8

A cleaner solution if you use a solid top, but less efficient that way:

https://www.engineeringforchange.org/static/content/Energy/S00069/Rocket%20Box%20Design%20Document.pdf
https://www.engineeringforchange.org/static/content/Energy/S00069/Rocket%20Box%20Fabrication%20Manual.pdf

You want to regulate fuel to lower the heat, not airflow. Reducing oxygen would kill efficiency and produce more CO.
 
Len Ovens
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Glen Cox wrote:
I would like to know if there are optimum dimensions and ratios in building a rocket stove?

As has already been said, ease of use and safety have been considerations. I am not sure where the 10inch height with 4 inch diameter for the riser came from except that the molds are easy to source (5 gallon pail and 4in drain pipe). Also the parts are light and easy to carry from where they are bought to home in places where everyone walks. If you are making a rocket kitchen like this, it is obvious the riser could be higher and the build of the "counter" could serve as the mold for the stove parts. However, in some of the RMH experiments, I have seen some very tall risers that still have flames shooting out the top. It seems the top of the barrel on a RMH where the torus forms is where the the finish burning takes place. I do not know if it is possible to replicate a spinning burn area in a cooking application.


I am looking for two things here, the best and most complete burn of my fuel (wood) and the best use of the heat energy for cooking.
I have seen many youtube videos that show short rocket stoves and it seems most, if not all commercially made stoves are short.
What I have noticed though is that there quite often is a lot of flame escaping from the top of the stove and licking around the pot, pan or pale.
It seems to me that there is a loss of efficiency and heat when this happens. I would think that making a longer (taller) chimmeny would put the
cooking surface closer to the tip of the flame where the highest heat of the flame is located. Am I correct in this assumption? Then if I wanted a
lower heat for slower cooking Couldn't I just regulate my airflow?


Rocket stoves are very easy to build. The very best way to satisfy your curiosity is to try some things. Maybe you will be the one to make the next step forward in wood cooking. This is also an area I would like to experiment in as I am sure there is more to learn.

Regulating air: almost anyone who has experimented with trying to get the cleanest burn, uses air regulation for cleanest burn and fuel regulation to change heat setting. With the rocket stove, add another stick for more heat, or pull a stick or two back out of the air flow for less. My diesel works the same way
 
Satamax Antone
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You regulate the fuel, not the air flow.

http://www.youtube.com/watch?v=VdhLWMW7IXA

Myself, i went for a batch rocket for cooking.

http://donkey32.proboards.com/thread/799/barbie-core-horiz#page=2 You can click on the disapeared pics.
 
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