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.

2018 Rocket Stove workshop

Our rocket-stoves journey

We have a journey of rocket stove building at Bhudeva… first it was the first rocket stove (bedroom, 2011), then fixing it (2012) then the second one (living room, 2012) and rebuilding the first one (2014).

We cook food and bake on both rockets most of the winter time.

It’s time to try a next step – we are going to rebuild the one in  the living room, this time we are going to make it even more efficient and add a heated bench for two on it :).

We are open to make it as a mini-workshop where you can come over and learn by doing.

The workshop

We will be building a rocket stove with a small mass attached to it and a place for sitting / reading / resting. It will be an opportunity to learn what were the limitations of the previous design (and why they were introduced in the first place) and the considerations that went into the new design. We will be building a typical rocket core with an attached brick chamber with some cob to add more mass and bring it altogether. It is a tight design that will fill a tight space.

You will have an opportunity to:

  • Learn about rocket stove design,
  • Participate in all stages of construction,
  • Meet the materials and the tools involved,
  • Spend some time at and learn about Bhudeva.

All within the settings and limitations of a traditional Romanian village house.

The build/workshop is estimated to take place in 15-17 of June 2018. The workshop time is Friday (half day), Saturday (full day) and Sunday (until 16:00). If you’ll join us, please arrive sometime Friday until 13:00 (so we can have the second part of the day for working).

There are 5 places available for participants. Sleeping will be in tents (there is plenty of space).  The price for the workshop is 540 lei / participant. We are asking for 200 lei in advance (bank deposit or transfer), when registering, for booking your place. The rest will be paid cash at Bhudeva.

Please acknowledge that English is the communication language at Bhudeva.

 

Living conditions

We are assuming you will want to stay at Bhudeva, however there may be other options one of which is a new pensiune just outside the village (a few minutes drive) which has recently opened its doors to visitors.

If you do choose to stay with us, here are a few things you may wish to know:

  1. You will be camping in a tent (that you need to bring with you). We do not yet have built structures to house other people. We have one small house which is a private space and we prefer to keep is that way, for now.
  2. We have one composting toilet in the house. If you stay here for a few days or more, you will learn not just to use it (make contributions) but also learn to care for it (emptying it in our humanure hacienda).
  3. We have a small outdoor kitchen. We are inviting you too cook together or, if this doesn’t suit you, please bring your own food. If we will cook together, you are invited to bring with you some of the next produce: “bob lung” rice, spaghetti pasta, avocados, honey from verified source (we’ll coordinate this by email).
  4. We eat mostly vegetables and fruits, with some dairy productions and eggs. Most of it locally (in the village) produced.
  5. We intend to be doing everything together: working, cooking, cleaning. We’ll see how this flows.

Visiting Bhudeva, you are going to encounter also our solar dryers, earthbag cellar (we are now at the green roof preparation), hugel beds, solar panel or other things we play with and experiment here.

🙂

If you’re interested to partake please write Iulia at iulia [dot] sara [at] gmail [dot] com… in English and include your phone number and the questions you want to be answered before coming to the workshop (and maybe during the workshop, if you already have something in mind).

Iulia and Ronen

The Rocket Mass Heater Builder’s Guide

This kickstarter was originally planned for last year … its finally arrived. Until now there has really only been one book on Rocket Mass Heaters by Ianto Evans, but having read it and built rocket stoves guided by it, I feel it is out of date (though I haven’t seen the latest edition). There has been much evolution since this book was written and I am confident this new book by Erica (and Ernie) Wisner is a much needed replacement for it.

If you are new to rocket mass heaters and you get to the kickstarter in time (there are a limited number of places available) I recommend the $75 bundle which includes the Village Video DVD – which is the best I’ve seen so far and I have a feeling will compliment the book very well (since it also follows a build by Erica and Ernie). That bundle should give you a very good start towards building your own rocket mass heater.

Dual Sun

A french company is bringing to market a solar panel that combines photovoltaic cells with solar hot water. The combination is not only interesting in a utilitarian way but promises improved performance of the PV cells by reducing the panel temperature (PV efficient drops as temperature rises).

DualSun-Panneau-Recto-verso

I wonder what this combination implies in terms of longevity and warranty. PV panels are typically rated to last more than 25 years. Would that still be true when they cease to be a simple static element and include flowing water? Is the panel leak proof (especially with the hard water flowing flowing through my pipes) for 25 years?

Tesla Energy presents Powerwall

no more batteries and battery rooms
no more charge controllers
no more grid tie
no more cable messes

tesla-powerwall

Tesla just announced the Powerwall one integrated unit to hang on a wall… a battery with a purpose … connect it to a photovoltaic array and (if you want as backup) the grid and you are good to go … at a fraction of the price of existing, more complicated solutions:

Cooking on a Rocket Mass Heater (Rocket Stove)

As winter set it and the rocket stoves started burning regularly I thought about using them for baking bread … which I do regularly and I thought would be great if I could do without having to use the electric oven. The stoves can be used for cooking but it takes them a long time to bring a medium/large pot to a boil … so I’ve only used them for a bit of partial cooking.

I remembered coming across (I think in the original Rocket Mass Heaters book by Ianto Evans) a kind of aluminum-foil dome that you could put on top of the barrel and use that as an oven. I was doubtful but decided to try making one. I thought about how to go about doing it for many weeks and came up with an approach that seemed feasible.

I built up a wire-frame that was designed to create two layers of aluminum foil (inner and outer) with insulation in between them. I used the commonly available in the village fencing wire … it wasn’t as thick or rigid as I would have liked it to be so I two twisted strands to get it to be more structural.

In these images you can see the continuous foil sheets, the inner layer already creating the dome and the rock-wool insulation going on. It wasn’t precision work … and it took much longer than I thought it would … I think I played around with it for almost an entire day.

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I ended up with something pretty fragile, funny looking … and honestly … discouraging.

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The structure wasn’t precise or solid enough to create a good seal with the top of the barrel … I didn’t think it could hold a temperature that could bake bread … and I just set it aside.

It took a few weeks until I decided to cook on the stove and to cover the pot with the aluminum cap. WOW … the pot came to a boil very quickly. I was surprised. I decided to give baking a chance … and boy did it work. The first couple of times I burned the bread a bit. I also ruined one of the silicon baking trays (and weakened the other one) because I placed them directly on the barrel top … and it apparently reaches a temperature much higher than what the silicon is designed to handle. I now place two flat (half) fire bricks on top of the barrel and the baking trays on top of them.

I now do a lot of cooking on the rocket stove. It takes some planning in terms of timing … for the cooking to coincide with the burning of the stoves. But with a bit more attention and intention a lot of the cooking is now done on the rockets. Pizzas are also now made on the rocket … much faster … tastier … and no electricity needed:

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Mamaliga goes on the rocket in small clay pots (that hold personal servings). Melted cheese on bread goes on … and more and more. There is a journey of discovery … what should be put directly on the surface, when to use bricks, etc … but the electric oven has been used very little in recent months. The gas cooker is also working much less. It is satisfying to be able to harness that is already there (and would otherwise rise to the ceiling) instead of expending (and paying for) more energy.

It works based on radiated energy. The aluminum foil reflects radiated heat back down onto whatever is cooking under it. It also locks in some convective heat (hot air rising) … I don’t know which is the more significant source of energy … I suspect the radiated.

One “problem” with the aluminum cap is where to put it when it isn’t used. Then a few days ago I had a thought … if the aluminum reflects radiated heat then couldn’t it reflect that heat back into the room. I went to the workshop and came back with a scrap copper pipe and used it to prop up the aluminum cap so that it reflects heat towards the couches in the room:

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… and that works too … really well … a very noticeable effect when you are sitting in the beam of heat that comes from the dome. I still need to bring in the copper pipe cutter to cut it down to size so that it can be supported with the edge of the barrel instead of projecting all the way down to the cob indentation … but it works.

What started out as a disappointment has turned out to be a really useful winter tool and upgrade for the rocket stoves 🙂

 

Split wood with a tire

I saw this video probably a couple of years ago. This year I ordered a new batch of wood and decided to give it a try … and all I can say is WOW! It doesn’t always go smoothly (depends on the size of the wood and tire, knots in the wood, etc.) … but it is always an improvement on hacking in the open. It is especially useful when cutting wood for rocket-stove size … generally smaller pieces than wasteful metal boxes.