Group Volcano Stove Build

[bbb]

It would be interesting to try a rocket stove with just an air gap as insulation (perhaps with baffles like a neo air if a plain gap is unsuccessful).

Also, you could try a BCB on top of the rocket stove.

[zelph]

It would be interesting to try a rocket stove with just an air gap as insulation (perhaps with baffles like a neo air if a plain gap is unsuccessful).

Also, you could try a BCB on top of the rocket stove.

Mine is just an air gap right now. I can add insulation to the inside can. I have 4" wide fiberglass cloth that will work nice. I'll have to see how the BCB fits onver the center can and also try the kelley kettles. My monster kettle will fit over the stove as is. Need an extension to support it. I think I can find something.

[ConnieD]

simplepeddler,

What tape did you use inside?

[sudden]

I have some vermiculite in the garage but after reading a bit I think pearlite is a better choice if you decide to insulate the stove. Vermiculite retains more water than pearlite so you would lose some heat due to steam and some insulating property till the water is driven off. That's if your stove got wet somehow.

[simplepeddler]

right now we are just using a aluminum tape.

It only holds up a few cooks though.

[zelph]

Big question......why insulate?

Where can we find comparisons of efficiency of two rocket stoves of the same size and designed in the same manner? We want to see comparisons that will tell us that insulating is most adventagious.

The can inside the #10 can is a little larger than a quart can. How much of a difference in performance can there be if we insulate between it and the outside wall of the #10.

Once the fire is going inside the stove we are constantly feeding fuel to simmer a cast iron pot full of stew or Jambalaya. Will insulation slow down the burn rate for us?

This rocket stove has a lot of strength, will hold a heavy cast iron pot. We don't want to make it taller to increase the draft for a faster burn unless we want to melt a lot of snow/ice.

[shingaling]

From the website: http://www.bioenergylists.org/stovesdoc ... iples.html

"1.) Insulate, particularly the combustion chamber, with low mass, heat resistant materials in order to keep the fire as hot as possible and not to heat the higher mass of the stove body."

I'm getting the impression that you want to keep the heat inside the 'burn area/chimney', as opposed to having the heat, um, absorbed (?) by the body of the stove.

I have a large amount of silica cloth (like fiberglass cloth, but much heavier), that I got at a thrift store. I had planned on using perlite, but I wonder if it would help (or suffice) to wrap the chimney with the silica cloth.

[ConnieD]

The greatness of the design of the rocket stove and this volcano stove idea, as well, is it puts the heat on the cooking and it uses very little combustable material to do so.

For a cooking stove purpose, there is value in having cooking stove not heat the surrounding ambient air.

What if you are in a hot or hot and humid climate? If it is Summer?

Do you really want to prepare food over a hot stove? Of course not.

There is a reason the oven/range in your house has insulation and is vented to the outdoors. It is not only safety from burning your house down, which is not very likely at all. It is the unwanted heating of the surrounding ambient air.

I do baking in Winter. I often have a cold meal in Summer. Why? It is too hot in the kitchen.

The other thing about insulation is, if you do not insulate the bottem of a burn barrel you will burn out the burn barrel. Of course, if you seldom use the burn barrel, the bottem of the burn barrel will probably rust out first. So you do not notice. So consider an easily replaceable screen grate or sand at the bottem of the burn barrel.

[shingaling]

What if the main chimney was made out of a double walled stainless thermos? Saw one this morning in a thrift store. Pain to work with, but would last longer. I guess it would add a lot to the weight, though.

I recently bought an old monster thermos with a glass insert. The outer shell is pretty big: 11 1/2 inches tall, diameter 5 inches (stainless). I was thinking of using it for the interior chimney, but that would make for one big honking stove. But if I used silica cloth to wrap the chimney and put perlite in the remaining space, maybe I could use the 5" sleeve as the outer body?

[zelph]

From the website: http://www.bioenergylists.org/stovesdoc ... iples.html

"1.) Insulate, particularly the combustion chamber, with low mass, heat resistant materials in order to keep the fire as hot as possible and not to heat the higher mass of the stove body."

I'm getting the impression that you want to keep the heat inside the 'burn area/chimney', as opposed to having the heat, um, absorbed (?) by the body of the stove.

I have a large amount of silica cloth (like fiberglass cloth, but much heavier), that I got at a thrift store. I had planned on using perlite, but I wonder if it would help (or suffice) to wrap the chimney with the silica cloth.

I agree with using insulation for the larger in house stoves as shown by the link to bioenergylist site. That is an excellent link, I have used it here several times. Lots of good info on one page for stove builders. Keep the house as cool as possible in countries such as South America.

In a small size stove made with a #10 food can there is actually no chimney, it's all fire box(combustion chamber). surprised you right. or we can call it a hybrid firebox with faux chimney assist.

Once the fire box(combustion chamber) is filled with nice glowing red hot coals Larry Winarski says just burn the tips of the fuel sticks. He says "regulate" incoming air, match it to the amount of fuel needed to accomplish your needs.

I say wrap your firebox with silica cloth enough to prevent dicoloration of the stove body. I'm going to do that with my stove.
Adding a chimney is like adding a fan says Winarski.

This quote is for reference from the link that you gave.

Dr. Larry Winiarski


Technical Director


Aprovecho Research Center


Apro@efn.org



1.) Insulate, particularly the combustion chamber, with low mass, heat


resistant materials in order to keep the fire as hot as possible and not to


heat the higher mass of the stove body.



2.) Within the stove body, above the combustion chamber, use an insulated,


upright chimney of a height that is about two or three times the diameter


before extracting heat to any surface (griddle, pots, etc.).



3.) Heat only the fuel that is burning (and not too much). Burn the tips of


sticks as they enter the combustion chamber, for example. The object is NOT


to produce more gasses or charcoal than can be cleanly burned at the power


level desired.



4.) Maintain a good air velocity through the fuel. The primary Rocket stove


principle and feature is using a hot, insulated, vertical chimney within the


stove body that increases draft.



5.) Do not allow too much or too little air to enter the combustion chamber.


We strive to have stoichiometric (chemically ideal) combustion: in practice


there should be the minimum excess of air supporting clean burning.



6.) The cross sectional area (perpendicular to the flow) of the combustion


chamber should be sized within the range of power level of the stove.


Experience has shown that roughly twenty-five square inches will suffice for


home use (four inches in diameter or five inches square). Commercial size is


larger and depends on usage.



7.) Elevate the fuel and distribute airflow around the fuel surfaces. When


burning sticks of wood, it is best to have several sticks close together,


not touching, leaving air spaces between them. Particle fuels should be


arranged on a grate.



8.) Arrange the fuel so that air largely flows through the glowing coals.


Too much air passing above the coals cools the flames and condenses oil


vapors.



9.) Throughout the stove, any place where hot gases flow, insulate from the


higher mass of the stove body, only exposing pots, etc. to direct heat.



10.) Transfer the heat efficiently by making the gaps as narrow as possible


between the insulation covering the stove body and surfaces to be heated but


do this without choking the fire. Estimate the size of the gap by keeping


the cross sectional area of the flow of hot flue gases constant. EXCEPTION:


When using a external chimney or fan the gaps can be substantially reduced


as long as adequate space has been left at the top of the internal short


chimney for the gasses to turn smoothly and distribute evenly. This is


tapering of the manifold. In a common domestic griddle stove with external


chimney, the gap under the griddle can be reduced to about one half inch for


optimum heat transfer.