Our Second Second Rocket Mass Heater

We finally decided to go ahead and rebuild our second rocket stove (the one in the living room). My primary wishes were to rebuild the core (better) and to convert the relatively useless mass into a (small) bench. Iulia decided to make it a workshop and …  3 interested people showed up.

During the first day we settled into being together. I left the existing rocket mass heater in tact so we could review its shortcomings together and learn from that. We talked about the basic workings of a rocket stove while talking about the existing stove.

… and then we took it apart:

We had only one wheel barrow of waste which was non-toxic and we dumped it as back-filling at the earthbag cellar.

Though there was some soot in the rocket (sometimes it didn’t burn completely clean) there was very little of it given that it worked for 6 winters. There was a 1cm layer of light and fluffy ash sitting at the top of the heat riser (accumulated over the same period of time).

Until we reached the brick platform upon which the rocket was built.

We then layed out the expansion of platform for the new rocket.

… and started building it … giving everyone their first experience at working with mortar and laying bricks.

The next morning we finished it!

With the platform done we built a mockup of the core (while learning about dimensions and sizing using standard brick sizes) and its place on the platform (and relationship to the bench).

We then settled into a rhythm in which two people were laying bricks (one working on the core, the other working on the bench) and two others were preparing soil for mortar and cob (and doing other support tasks such as cleaning bricks so that the brick layers could work smoothly).

As the chamber that is under the bench started to take for, I figured out how we were going to close the top of the chamber  (close from the chamber that makes the bench. The plan I came up with involved recycling two concrete slabs we had lying around together with some bricks. Next I had to figure out how to create a structure that could support that top while allowing a good flow of gasses through the chamber itself. It was a bit of a puzzle but we solved it.

… and the core was rising up

… and the chamber was rising up … and we were starting to apply cob (especially on the back side where access would become more difficult as the construction grew):

… and I think this is where we finished up on day 2:

On day 3 as most of the riddles were behind us and everyone had a better sense of the materials and the work, progressed flowed and accelerated. The core was completed and the chamber layout finalized. While the chamber was being closed up the heat riser was growing.

Pretty soon we were insulating the core with  perlite in a clay slip (recycled from the previous rocket) in the chamber built around the core:

… and then the insulation sleeve around the riser was put in place (recycled from the previous rocket) … and also filled with perlite:

… and finally the barrel came on (for the last time – we had quite a few fittings), we sealed all around it with cob … and lit the stove … and despite adverse conditions (a new rocket filled with moisture, on a warm summer day) we all smiled when we saw the flames getting sucked into the rocket and the dragon came to life. Very soon we were in an overheated room with a warm bench (that nobody wanted to sit on).

… in the excitement (and a bit of rush to accommodate the schedule of one of the participants) I missed taking a picture of the barrel on the “raw” rocket … but the next day (today!), with Liam’s help preparing soil and mixing cob, we were able to get much of the cob work done (and we may complete the rough structure tomorrow).

Even though it is using the same floor area as the previous rocket, the footprint of the new build is much larger … and it dwarfs the room … which feels a bit off. That is a price we’ve paid for having a warm bench to sit on (without taking on a much larger renovation).

It was an intense weekend. I’m glad to have had an opportunity to share rocket stoves with Tudor (missing from the picture below because he had to leave before we took it) , Dan and Liam and Iulia. I’m glad to have a good core with hopefully a comfortable bench for next winter.

Buried Home in Omaha Nebraska

I enjoyed this video of a house that was apparently built (~40 years ago?)  by a pioneering thinker (Lloyd Texley, the former head of science for the Omaha Public School District). It gives a good idea of what is possible and I can only imagine what additional improvements and potentials lie ahead:

Catalan Brick Vault

What a wonderful skill  … beautiful work with a basic element and basic tools. I can imagine something like this being built over eathbag walls (though I don’t know about using it for an underground roof that may carry alot of weight … will it hold?)

(Very) Passive (Not) Solar

The only place we’ve seen sunshine for the past … oh … I don’t know … at least a week, maybe two … was on a video call with Annelieke in Portugal. And this is what the 10 day forecast looks like:

This is that time of the year where the sun can be absent for weeks and the temperatures drop … and the theory of passive solar design simply cannot deliver. We simply cannot rely [for warmth during our winter months] on a daily cycle of solar charging and discharging.

That shortcoming hit me during the first winter at Bhudeva … and that is why I got excited when I discovered Passive Annual Heat Storage which is about creating a YEARLY cycle of charging abundant summer warmth and discharging it during winter.

Earthbag Cellar – Walls Done!

After winding down from the full-house weekend … we got back to our “regular schedule”. Marta stayed with us a while longer and helped us get almost to the finish line.

We were excited to finally get to level 21. Here we are passing over the front arch for the first time:

When we finished that wall segment we finally got to pull out the forms … and … it was exhilarating to unveil the self-supporting arches … so simple, powerful (the more we weight we put on it – and we will be putting on quite a bit – the stronger it gets!)and beautiful (I’m really glad we decided to give arches a try!):

Yesterday we finished, with Marta’s, help going all the way around the structure and were left with only with two small segments of the outside wings.

Today Iulia and I went out and completed those two small segments – counting down the last of 6 sacks … and suddenly the the last can is tossed up, the last sack is placed down … the last tamping … earthbag walls were complete!

Fascinating journey from a crater to a structure… made of the same earth we dug out!

We are now waiting to see if we can get the acacia logs we want to make into a roof (our preferred option). If we do, they will be freshly cut and will need some time to cure … meaning that we won’t be able to place them on the structure before winter. If we don’t get the logs we will rever to plan B: regular 2×8 to build a flat roof. That may still happen in the coming weeks.

Depending on the weather we may be able to get some more primary rendering work done … but that is optional … maybe continue with the electrical wiring …  I am relieved and satisfied we got this part done … much to share … too tired to do so now.

 

 

Earthbag Cellar at Level 20

Iulia was a way for a few days and I took the opportunity to do some initial finishing tests.

Then Iulia came back and brought with her a wave of people. We’ve just been through a full weekend here at Bhudeva. Christina and Marta came out to help in the final levels and they were joined for one day by Luci and Stefan. We’ve completed 19 and are two-thirds into 20.

It was moving to see 5 people on and around the walls working in two teams … until this weekend I could only imagine what this might look like.

AND the day felt way more productive then the already productive work we did get done … because soon after as we started level 20 … Iulia and Chritina got to work on this sack:

… and when they laid it down and, after tamping, it met the top of the arch, it became clear to us that 21 would be the last level … and the idea of level 22 disintegrated and we were suddenly another level closer to finishing the walls:

If all goes well we should be finished in a few days. Our fingers are still crossed that the acacia logs for the roof will be cut down soon and that we can get them to Bhudeva and get them on before winter.

Earthbag Cellar at Level 19

The day before yesterday we finished level 18. Yesterday we started level 19 by putting in the ventillation pipes (for air flowing out of the two rooms). We cobbed them in place and then continued to work aroud them.

Today we focused on the arch above the entry door … and we started by adding two more arch pieces on each side until we were ready for the last 3 sacks that cap the arch.

… and cap it we did

I am soooo looking forward to taking out the forms … but holding off until we add the final layer on top of the arches 🙂

I thought we would be able to finish with 21 levels … but now that the first arch is complete and the highest point is set it looks like we will need to go up to 22.

Iulia is going away for a few days … after which we hope we will be able to finish before deep frosts settle upon us (temperatures are dropping rapidly).

If all goes well (we will in the coming days) we wil have acacia (strong and rot resistant) logs to cover the entire roof … keeping our fingers crossed that we will be able to close the cellar before winter!