Rammed Earth for Everyone has some very interesting rammed earth cookstoves and wood stoves with lots of photos that show how they’re built. Looks simple enough for any do-it-yourselfer. Cost would be negligible if the forms were reused to build additional stoves.
Where is it showed how to make the rammed earth cook stove and woodstove?
I’m not sure, but you can probably find instructions for similar stoves made of cob for free online. Cob would be easier to work with than rammed earth. Please tell us what you find.
There are many ways to preserve the appearance and dramatically increase efficiency.
One could easily cast sawdust/clay bricks and fire them. The sawdust burns out leaving a insulating refractory brick that would be a very effective liner.
Pumice or Scoria as you mentioned (along with perlite) are another option, but probably would need to be contained inside a metal liner, or cast inside some fired sawdust clay refractory brick mentioned above.
I seriously doubt these rammed earth stoves, as currently designed, are smokeless, especially during startup. They will take a significant length of time to get up to temperature, and all during that time, they will produce smoke from the cold combustion chamber. They look like they are a perfect design to produce large amounts of carbon monoxide, one of the worst toxic gasses produced by combustion.
Rammed earth is very high in thermal mass, and should not be used as liner for a combustion chamber.
Thermal mass is best utilized downstream from the combustion chamber to capture heat from the fully combusted hot flu gasses and slowly re-radiate that heat a room. A rammed earth bench, similar to the cob benches typically seen with rocket mass heaters could be extremely effective as well as attractive.
I’m not at all opposed to the idea of using rammed earth in conjunction with a stove or heater. Actually I think it’s a great idea in principle. More thought needs to be used to improve the efficiency of the design, especially in areas where deforestation is happening, like Chad.
Hopefully this group will improve their design.
Agreed. It’s a good idea in some ways (extremely beautiful and durable outer surface) but needs improvement. This is a good opportunity for people to upgrade the basic concept. It doesn’t cost much to build a stove like this and would make a fun experiment. Please send us your design ideas and maybe we’ll post on this blog.
I applaud their use of local materials.
Sadly, this design is very inefficient.
It requires a significant amount of fuel simply to heat up the stove instead of using that fuel to heat the food.
This design could be dramatically improved by mixing sawdust with clay and ramming that into an insulating layer around the firebox, by allowing air to circulate under the fire, by providing better draft, and by assuring better heat transfer between the fire and the cooking pot.
The Lorena stoves, as well intentioned as they were at the time they were first introduced, were never particularly efficient.
The following document gives great technical information in a very easy to understand format for building an efficient stove:
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCQQFjAA&url=http%3A%2F%2Fwww.aprovecho.org%2Flab%2Findex.php%3Foption%3Dcom_rubberdoc%26view%3Ddoc%26id%3D22%26format%3Draw&ei=XtEBU6C4FOrL2gWAwoCYAg&usg=AFQjCNH3PU2J48s4ErcEZcGfiRjwxpxpkg
I do like the appearance of that rammed earth fireplace. If some of the efficient design criteria were applied to that design, it could really be very nice.
Agreed. I was trying to figure out a way to improve the efficiency. They sure look good and would probably last a very long time. They could put volcanic rock in between the firing area and the outer layer. That would complicate construction. I saw one Lorena stove made with cans for burn chambers like a rocket stove. You could put volcanic rock around the cans and then do rammed earth for the remainder.
The pots could be recessed like Lorena stoves:
http://autonopedia.org/wp-content/uploads/renewable-energy/Wood_Cook_Stove_Design-19.jpg