Hi there, my name is Sonny and this can act as my formal introduction to you all. I've been a long time lurker of this forum, and only now I feel I am ready to post my first thread
. As I mentioned, my name is Sonny and I am 21 years old at the time of this post. I have studied and apprenticed at CalEarth Institute and taken every Superadobe course
that they offer. Some of you should
hopefully already know what CalEarth Institute teaches and for those of you who don't, they teach sustainable
earth architecture based around strong shapes; such as domes or vaults. This is my passion, and I am so lucky to have already discovered what I want to do in life at such a young age. I know this could of course change, but I know for certain I am going down a good path; wherever it may unexpectedly lead.
My reason for posting this thread is that I, first of all, would like to document my progress on building my first rocket mass heater
, as well as receive any advice from all of you knowledgeable folks here at Permies. I have read many books
regarding the subject of rocket stoves/rocket mass heaters
and I know the basic fundamentals and principles, and with that being said, I probably will not be asking many beginner questions. However, there are numerous questions that I do have, which are not easily answered by searching Google, or Permies for example. As I mentioned above, I build with the earth and I have a structure in particular that I built for my brother in Northern California. This structure is going to house my very first rocket mass heater
. I have gathered 90% of the materials that I will need to build this rocket mass heater
, and I am nearly ready to start assembling it. I figured I would post here first in order to straighten a few things out and organize my thoughts. Below, I will show pictures of the structure in which I will be building my rocket mass heater
Note: if you are only interested in the rocket mass heater aspect of this post, scroll down towards the bottom and you will find where it says "Rocket Mass Heater Section"
As you can see, it is not by any means a conventional shaped building. This was constructed entirely out of earth, and once again for those of you who don't know, this is what CalEarth Institute teaches. This dome is a 12' diameter with a 2' spring line, and I know it is difficult to interpret how big or small this structure is so I will tell you it is 14' tall. The purpose of this dome is not to act as a usual home, but rather a change of physical environment for my brother Tommy who will use this structure as his tea house. I will quickly note that my brother Tommy suffers from muscular dystrophy and that I built this dome for him so that he can take his passion for tea to a whole new level. Here are some more pictures of Tommy's tea dome:
Below, I will show a brief reference to the building process. (In case it is unclear, this structure is built by filling long polypropylene bags with earthen material. Two compasses are used to ensure a symmetrical dome. Barbed wire is weaved between each layer of bag. Each layer is also tamped with a cast iron tamper to compact the material. The structure is then rendered and plastered leaving guests wondering what the structure is made out of.)
It all started with a scale model of what we wanted to build, a single dome with a short entry vault:
We then mapped out our building site and began digging the foundation:
Our first courses of bags:
Fast forward a few months:
And then fast forward to the completion of the bag-work:
That brings us to now, and it is very close to being a complete structure. All that it is missing is a source of heat, which is where this post is heading.
I'm going to draw up some plans
for the rocket mass heater very soon, and I will edit that in. For now, I will post the original floor plan of the dome for reference:
Rocket Mass Heater Section
Here is a picture of the dome's interior where the rocket mass heater will be constructed:
I've narrowed the placement down to this spot between the center and left windows. The bench will run along the perimeter of the dome and it will stop at the very start of the window on the right:
Details About My Rocket Mass Heater And Questions For Whoever Is Reading
Hopefully, you can understand the shape I am trying to create for this rocket mass heater. It will be circular shaped, following the exact contour of the wall and it will be roughly 18" high and roughly 20" wide. As I mentioned above, I will draw the plans
for the stove soon which should clarify my construction idea.
As of right now, there are a few things I am uncertain about. First of all, I plan not to insulate underneath my first layer of bricks or near the wall as this structure is all one big chunk of thermal mass which I want to heat up just like the bench. The floor is a 4" thick concrete
slab with a vapor barrier underneath, and the walls are made out of adobe. I am curious on any of your thoughts regarding my ideas here, I believe I am correct in wanting to construct the stove in this manner. Let me know what you all think
Second of all, I am uncertain of my chimney and how high it should be. In the picture above, I have a piece of 8" stove pipe that is 5' tall. I don't have a chimney yet but it will be placed roughly where the silver colored stove pipe is in the picture above. I'm going to carve an 8" diameter hole right above this pipe for my chimney to exit vertically. Is my chimney in the right place? How high should it be after it exits? These are things I have no way of researching as most people
aren't building rocket mass heaters in dome-shaped structures.
These are my main two concerns at the moment, and I'm sure I will have more as I progress.
A few details I should mention are that I am building a J style rocket mass heater based off of Erica and Ernie's work. I have copied their 8" system dimensions leaving me with a 50" heat riser, a 24" burn tunnel that is 7.5" x 7", and a 16" feed
tube. My barrel is stripped of paint, and ready to go. My bricks are refractory good up to 3000 Fahrenheit as well as my heat riser split bricks. I'm going to use clay mortar for all of my bricks, and this is something else I am a bit uncertain of. Should I use just clay slip, or clay and sand? The bricks are pretty symmetrical, only a few gaps here and there. I have a ceramic refractory blanket which will insulate some of my burn tunnel and all of my heat riser. This will be wrapped with a wire mesh. My manifold will most likely be made out of brick in an octagonal shape, although I am tempted to buy another barrel to use instead. Any recommendations on this?
My stove pipe will run about 15' before making it to the chimney. It will follow the wall to the far right window and then loop back towards the chimney. I'm going to utilize many 90 degree elbows in order to make this work.
Once the heart of this rocket mass heater is complete, I will be using cob
to render the bench. I think that is the gist of my build and I am very curious to know what you all think. Once again, this is my first time building a rocket mass heater. Though I have done my research as much as I could before posting, as you can see I am working with some variables which are not all that common. I appreciate any feedback or advice and thank you for reading my long post if you made it this far.