These collection of clips are from the desert in the south of Israel. These are usually sudden events (though fairly predictable after rainfall events) in otherwise open and dry river-beds. Vast amounts of water that could have been held, directed and put to some kind of ecological use … but most of it just flows through (I don’t know where to).
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.
I ended up with something pretty fragile, funny looking … and honestly … discouraging.
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:
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:
… 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 🙂
Lovely short video … hint … those lines between the trees are not strings or ropes!
These images were taken at the warmest time of today ~16:30:
The day before yesterday when I went to the market at 08:30 it was -5c. Looks like winter is settling in.
The summer was fairly wet. During the 6 weeks I was away it rained every other day. The grasses have been continuously green. The stinging nettles were productive all through the summer and until a couple of weeks ago.
Fall was fairly dry. There were a couple of rain events but nothing major … didn’t have much effect on the rain barrels … it was a very good year for mice and flies (signs of the last of both species are finally fading out of the house). Snow has not yet made its first appearance … though according to the forecast it may arrive any night (I just covered the piles of wood in the picture above in case snow or slush does arrive tonight).
The first wave of cold came relatively late … around mid-October. I started heating the house with the rocket stoves around that time, but not every day. Shortly after that I had to empty the solar hot water system to prevent it from freezing … so showers have also been based on wood-burning since then.
For the last 2 or 3 weeks the rockets have been burning every day – a morning burn in the living room and a night burn in the bedroom. During the last week there has been a noticeable drop in temperatures … I have had to feed the rockets 3 batches instead of 2 … and on a few days I’ve even had to do a second burn during the day to keep the living room from getting to cold.
Yesterday, when the images above began to unfold I finally moved into a thermal under-layer of clothes and have had to put on quite a few layers when going outside. Hurting hands have set in too. The kitchen (entrance hall to the house) is becoming less pleasant to be in since it is only heated indirectly (heat that escapes from the two adjacent rooms and from cooking). Ricky, the small dog, has started spending nights inside. Rain water barrels are freezing over night, I can still break through the ice in the mornings … but I don’t think I’ll be able to do that much longer … I think I’ll have to empty them soon.
Days are short. I have settled into a winter rhythm that involves the routines of heating (carrying wood in, starting and feeding fires) and living in between. I still need to change the main water filter and add the final layer of insulation (straw bales and tarps) on to the two man-holes through which the water supply system passes … and may this winter be warm and pleasant.
Winter is here.
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.
the village is in a low spot and we are in a valley so it can take some time for the fog to lift … sometimes until noon … until then I need to either run on faith (or drive up and out of the village) to know that the sun is indeed shining.
It was on my mind for many months … rebuilding the first rocket stove. It worked good – though not great. There were some design errors and compromises and during the last winter there were more smokeback events that I could not explain. I wasn’t keen on taking apart something that (kinda) worked and embarking on another build project. So I played around with it in my mind for a long time. Eventually I had a design I felt comfortable pursuing, I did a simple cob test to confirm the materials I had … counted and purchased bricks … and decided to go for it.
At the last minute I decided to give it a chance to become a workshop build and so I published an invitation and sent out word to people I knew and thought may know other people who would be interested … this was 3 or 4 days before the planned weekend build … and once person did sign up … making him the first participant in the first workshop I have ever offered at Bhudeva. I had two pairs of helping hands – Annelieke and Horatiu.
The project was born when I did created this layout:
I was able to take real measurements, finalize brick counts … and get confident enough about my vision to move forward. The first thing we had to do was to take apart the existing stove … which was magical … the knowledge that most of the materials can be reused … that the rest are non-toxic and can simply be tossed out anywhere on the land where they will be reassimilated by nature … its one thing to know this and another to experience it:
I was surprised to find the metal heat riser mostly in tact … though it was dry and chipping. Most of the clay-perlite insulation was used in thew new build … which … began by recreating the layout in place to find the exact position it would be in relation to the existing chimney.
With the position fixed we were able to get to work on building a raised floor:
And then, layer by layer, building up the core of the stove:
… and when we brought in the barrel for a first fitting it started to feel like it just might become a real life rocket stove:
In the following image you can see the experimental part of this build. I discovered these honeycomb bricks and decided to use them to easily create heat channels and storage mass. There are two air passages (barely visible in the image) that allow the hot gasses to flow from the barrel into the two-brick chamber on the left hand side of the image – where they flow up. Then (as can be seen in later images) there is a top chamber that allows the gasses to flow across and down the two-brick chamber at the top of the image (right up against the wall) – where they flow down and then out through the chimney. There were three experiment going on: 1) using honeycomb bricks; 2) introducing a vertical flow both with both bottom-up and then top-down flows; 3) and gaining improved heat storage by having mass outside (the shell of the bricks) and inside (the honeycomb pattern).
This is as far as we got in the two days of work we had available. Horatiu and I agreed that he would come back for another day of work during which we will complete the build and fire it up for the first time. So during the next few days Annelieke and I continued doing some preparatory tasks. The most prominent task was the heat riser. Annelieke started doing a perfect and wrong job. Can you guess what is wrong in this image:
Annelieke is doing fantastic work getting the bricks aligned and leveled … but she is laying them without overlaps … creating a beautifully symmetric and unstable structure. This is something I take so much for granted that I did not spot until a few more layers were built and it became very prominent. So It had to be taken down and rebuilt properly:
While she did that I built some insulation chambers around the core (to extend the insulation that would be placed around the heat riser) and started filling them with the clay-perlite mix from the old core … and as you can see in the bottom-left corner I started playing around with cob … hoping for a better experience (I’ve had very poor experiences in the past):
On the day Horatiu came back we finished building up the honeycomb brick chambers and the top chamber in which gasses could pass from the up-flow chamber to the down-flow chamber:
The top chamber was closed with bricks and we then added on the sheet-metal container for the insulation:
… filled it up with clay-perlite insulation:
… and sealed it:
… and suddenly that was it … everything was ready for a barrel:
… and lighting a fire … the smoothest lighting of a new rocket stove I’ve ever experienced … excellent draft (probably helped by the fact that the core had a few good days to dry):
I was then left on my own to slowly transport cob-worthy material, to mix it up in reasonable one-person batches … and slowly build it and transform the stove from something very mechanical and engineered to something organic and mysterious:
There were a few places where seeds apparently got into the cob mix … and given that there was a lot of moisture inside this happened, in a few places:
It now, though still slowly drying, looks like this:
The second lighting of the stove, in contrast to the first, went very poorly. I am guessing it had to do with the loads of cool moist cob. This is where the experimental part may have also kicked in … the gasses may have had a hard time establishing a complete and continuous flow throughout the stove, resulting in serious backsmoke. During the third lighting I was careful to preheat at both cleanouts, to start very gradually and only when the stove was flowing well to put in a full load … and … to my great relief … it ran perfectly again. The fourth lighting was not so good … I wasn’t as patient. Since then I’ve lit it a few more times and it has been going fine.
I estimate that, aside from the bricks, I put on over half a ton (maybe up to three quarters) of cob. Thats a lot of moisture. At the end of the first lighting (before cob went on) when the full load finished burning the bricks at the back were noticeable warm. Not so during the next few lightings. There are many liters of water in there that need to dry. This is something that should be taken into consideration in a construction schedule. I started the construction early so there would be time to experiment and make corrections. I did not take into considerations how long this would take to dry … it still is drying.
Cob was much more friendly this time … finally. I played around with different finishing techniques … I still am. It is a subtle thing finishing and there seem to be numerous paths to go about it. It is very pleasant work (when it works) to be able to mold shapes, smooth corners, add colors. It felt like a complementary and balancing process to the more structured, measured, aligned process of building the core. It felt free, open, secure, … embracing and welcoming. It is a pleasant way to finish a build and a much more pleasant result 🙂
The stove has already worked for a few cold nights. It’s still hard to say how good it works because: its not that cold yet, there is still humidity in the mass, the barrel itself is partly wrapped in cob … so a few things still shifting and changing. I am looking forward to experiencing how it works … both the immediate heating and the heat storage for the night. I have a feeling that it is going to be more efficient in terms of wood consumption (then its predecessor) … I am curious how it will compare in terms of heat storage (the previous stove was all storage, slow to heat up but then radiated plenty of warmth throughout the night – sometimes even overheating the room).