Rocket heater from cob and cheap insulating materials that poor Lebanese and Syrians can make

Hi everyone,

This post is about making a rocket heater (with possibly a little mass) from locally available, cheap materials, that poor people can buy and make heaters with.
Location is Lebanon in the Middle East. Most people (about 90%) are now poor (some info on this at the end of the post). People use diesel and wood to heat their homes in little cheap stoves. And the poorest burn plastic, black motor oil, shoes, clothing etc. Imagine the cost for health and environment...

I would love to build a prototype rocket heater, with a little mass, that is built from cheap local resources that will save people money and health.


Limitations
A further limitation is the size of exhaust pipes: Most houses have exhaust pipes in the walls of apartment buildings of 10 cm / 4 inch.
Hence the little mass, otherwise the draft would become a problem.
O, and people live either in houses that are not insulated, or in tents.
Minimum temperature in our house gets to be 4 degrees Celsius (39 F) in the morning, regardless if we heated our house the night before:).
Also we have to open the windows at night: they build the houses so bad that all our walls and ceiling are wet.

Local resources
Resources in Lebanon seem to be: red fire brick (weighs heavy and used in chimneys and pizza ovens), clay (red, contains iron), ‘fire earth’ (looks like coarse sand, brownish and used also for building chimneys and pizza ovens). Maybe the latter is some type of fireproof mortar. They mix it with sand and water.
And finally I’m checking out what they use for pottery as this is an old craft in Lebanon.
Technical information about what temperatures etc. are completely unavailable so far. It’s Lebanon…

Your experience can help me!
So…I’d love to hear from people having experience with 4 inch/ 10 cm rocket heaters with little or no mass that DO have that second burn.

And possible insulating materials besides ceramic wool, vermiculite and scoria. Perlite is maybe available as Turkey is close and a big producer. But haven’t found that one yet either.

Last question would be: what is the hottest it will get in a 4 inch system?

Info on Lebanon for those who like to know:)
Known widely for being little Switzerland (banking sector, mountains, beautiful) and for it’s medical sector, Lebanon has deteriorated in a third world country in a few years. Years of corruption, political deadlock, bankruptcy and an influx of Syrian refugees have devastated the country. Since the revolution of 2019 this has accelerated and now basic commodities like gas, water, bread and electricity are sometimes suddenly unavailable or scarce. There is little to no hope the situation will improve in the near future.

I thought there was a thread on here about someone who taught Africans to build rocket stoves. They used the ash of banana leaves to insulate the stoves, I believe. I will see if I can find the thread for you.

EDIT: I have found a few mentions. Building Earthen Stoves

In Haiti they build rocket stoves from mud. https://www.rechoroket.com/

Hi Jeremy,

Thank you so much for looking up this post and Haiti link. They provided me with so much information and most importantly hope that I can effectively build with a cob mix that has insulating properties. Just amazing what has been already done in poor countries. I can really recommend the Haiti link to everyone, as well as the following link: http://dancelikeanelephant.blogspot.com/search/label/clay%20and%20cow%20manure%20plaster.%20cooking%20in%20an%20earth%20oven

Detailed instructions and all cheap locally available materials. Couldn't have asked for more!

Will hopefully be able to start experimenting soon. And if it all works out I'd like to share my experiences with efficiency and durability some day.

hello , some info i read whilest looking up ideas for my own stove ,lots of stuff on the M.H.A of North America site    , for some real hands on and use of basic materials to build a working stove, Cinva Ram Earth Block Heater with Tom Trout  , and Energy Efficient Cooking and Heating Stove by Richard Jussel , hope it inspires

Since you mention a restriction of commonly used 4"/10cm holes in walls for heater exhaust, I want to mention that 4" J-tubes are smaller than the common sizes that work well in ordinary builds. 6"/15cm is the smallest reliable J-tube system size. However, a 4" batch box system scales reliably if built according to published dimensions. Batch boxes take more skill to build than J-tubes, but deliver heat faster for the same size of system.

I would not advise building a batch firebox from cob, but at least common brick if firebrick is not available. This is because the wood will be rubbing the firebox sides and cob would be damaged easily. Perlite/clay works fine for heat risers, using a sacrificial inner form which will burn out and a light sheetmetal outer form which strengthens the riser permanently. Mine on my 8" J-tube is still working in its seventh season. A 2"/5cm thickness of perlite/clay works well for me.

Hi Glenn and Tony,

These are some great ideas! I'd love to test them out soon, however time is a bit short right now and the season is not right to start building stuff.
With the snow we got everything died down (activity wise) in the parts we live in.
Just before however, I was able to find a local pottery that supplies clay mixes as well. He was quite an expert (a rare thing here) and enthusiastic about the idea of a RMH.
However, he imports everything from the States and it's super expensive. The good news: he was able to give me a number I'll try soon of a guy from Switzerland that immigrated a long time ago and makes pottery and firebricks from local clay. Very exciting stuff. He also knows his business so won't give me nonsense answers (as most people here do..).

Love the idea of a batch firebox. I read about it on https://batchrocket.eu/
A lot to think about. I think first I need to know what is available locally and rather cheaply.
Then start playing with mixes of cob.
Then build a prototype 4 inch system to see if I can get it to work.
Then see if I can adapt (for tents it's probably not allowed to build something from brick, they don't want structures that will turn in to houses).

Thanks again!