Monday, September 17, 2007

Developing New Cooking Stoves for Huamanzaña, Perú

Perhaps the latest big fork in my path to becoming a better "technical humanitarian" was when the EWB network led the student chapter of EWB-Princeton to me, as they looked for a "mentor" for their next visit to Huamanzaña, La Libertad, Perú. They have had a history with Huamanzaña resulting from a number of visits there (see Shannon Brink's blog at for more details, and recent posts - then see their photos of the village, people, and the surrounding landscape here), and their next project was to build stoves for each of the 35 families, to reduce indoor air pollution (IAP). It is always an honor just to be an invited guest, but I had to quickly check my qualifications - South America is my recent general area of interest (just due to the predominance of one language there), I am very fond of small villages and don't mind the hardships that come with that kind of territory, the problem size and scope was manageable as far as I could tell, and I wanted to get more experience with one of the few stove types new to me - what I call "chimney stoves", where an important goal is to reduce IAP (vs. all the other noble goals that fuel efficient stoves can achieve as well). I look for opportunities where my past, more corporate, experiences in R&D, new product development, marketing, lean manufacturing, etc. can be employed and this project seemed to have it all. As usual, no detailed information on what works best (materials or design) for these permanent, typically masonry, stoves seemed to exist, and the challenge of using only local (and unknown ahead of time) tools and materials is something that must be anticipated - little can be planned for, just show up and start solving problems.

After the typical laborious process of just getting there (taxis, buses, planes, buses, taxis, planes, worse buses, and then the minivan to the end of the line - Huamanzaña) I found myself in the foothills of the Andes - an extremely sandy (sand surfing on giant steep dunes!) area near the Pacific coast and southeast of Truillo (second largest town in Peru). Several small towns past consumer buying opportunities and electricity - perfect. Great students and townspeople to work with, few distractions from the work (nothing was there - they can't even afford vices), but almost no easily identifiable tools or materials to work with except for a broken hammer, 2 decrepit buckets, and lots of stones (the village is in a river valley). Chao is the nearest village with stores - the Pan American Highway runs through it and every hardware store carries the same poor collection of inferior quality tools. It is two hours away, and the minivan runs most days, but you can't get there and back in the same day - patience is everything.

Huamanzaña families use "stoves" typical of the region - nothing more than two rows of bricks with a fire burning between them, and some scrap metal pieces across the top that pots can balance on. They do use them very artfully though, placing pots at different distances from the center of the fire - to vary the temperature - and they can of course cook beautiful food, already, and many dishes at one time. Helping them cook better (or even with less cost or effort) is not why new stoves are desirable - the problem there is that they presently use no chimneys so the smoke at best filters slowly through leaky walls or wafts up toward a hole in the roof. And of course the smoke represents unburned fuel, requiring them to cut more wood than they actually need for their cooking tasks.

I believe in first doing a "resource analysis" for every new project - what things exist nearby (wood/burnables, construction/building materials, skills, traditions, raw materials, waste, etc.), what do they cost, and how far away are they? Basically, what can people burn for cooking (waste materials and other natural resources) and what local tools/materials can we martial to help them do it better? If its not local I don't want it (unless it is small, and key to a project - for this one it turned out to be just masonry blades for a hacksaw) - so we went around and introduced ourselves to all of the nearest merchants, bakers (they use stoves too), blacksmiths, auto junkyards (rare in Peru, but they have tools and access to metal), brickyards, lumberyards, hardware stores, carpenters, and anyone else who might know someone who might know someone who can help with a project. My favorite blacksmith "el Gordo" ("fatty" to his friends, but I call him Juan) kept us going in Chao - and will continue to in the future - because he shares the same vision in life that I believe in (work hard, learn everything, network, be passionate, kick ass, hopefully get ahead). Local construction materials included mainly sand, rock, soft bricks, cement, and wood ash - of course no electricity, and we could only borrow a wheelbarrow occasionally.

So we forged ahead... we found local bricks that had lots of holes (like U.S. "cinder blocks", and with thinner walls - up to 8 holes in each, so the cost per unit volume was better than solid brick) so good open area that could be filled with ash (the only insulating material we had, short of starting up a brick kiln), we decided to prepare for earthquakes by supporting the chimney internally with poured concrete inserts, and we were off - as long as the resident guinea pigs (called cui, an important source of protein) didn't object to construction in their kitchen homes.

We had been VERY lucky to happen upon "honeycomb" coal stoves (like in China, but bigger briquettes) used by outdoor cafes, and then found the refractory brick shop in Trujillo that made the liners for them (not porous, but heavy - he didn't know about the occasional benefits of holes) - since he would cut the "door" opening for us, it was an easy combustion chamber to use (instead of his rectangular bricks). The whole kit for each stove included this: the hollow bricks, ash from the bread ovens, cement, steel reinforcing bar, and 8 bricks for the chimney - plus the 6 mm thick plancha and the equally robust perforated steel grate (and some floor tiles, and...). Someday we'll know whether an ash insulated area is the best - for now it seemed to decrease the thermal mass of the stove as a whole and lead to faster boil times. We created an informal system where more insulative construction materials were required closer to the combustion chamber, and gradually less appropriately insulative materials (such as denser rubble - concrete, bricks, etc.) could be used as the local temperature was lower in that particular area. We were too rushed for many performance measurements, but it will be easy to later improve this design. It would be fantastic if we could eventually use the local stones for building stoves too. The plan was to design each kitchen for the individual cook - at least as far as surface height, stove layout, and food preparation space were concerned - providing obvious additional benefits should help cooks adopt the new stoves more readily. Using bricks of several varieties, it was possible to come up with a small variety of designs for different kitchens - our philosophy was to use as few parts (so larger bricks were favored) and steps as possible. Most of the hard work has been done since I left, so we look forward to how it all worked out - the latest reports on cook satisfaction sound great.

Unfortunately, our first home was not quite prepared for us, so just the 2 gringas and 2 gringos had to first do extensive repairs on the concrete base that took too long. And the first stove itself is always a challenge as you learn to work together efficiently. And since by then it was my last day, I was guilty of pushing everyone too hard - from my manufacturing point of view developing a good procedure is so important that I was worried that future stoves would take too long unless we worked out most of the details on the first one.

Meanwhile, back at the comedor - our test kitchen with the very first stove model - it was proving challenging to convince people that this was an improved stove for them - since both stoves and firewood are "free" there they found that the increased time to boil was a terrible disadvantage; they are people busy in their fields, so the time saved by putting pots right in the coals was important for them. We cooked and had a town party, and that plus improvements in the design after I left will hopefully result in them using the new stoves as they are designed. When there is even the tiniest flame there is no smoke coming out of the chimney, the outside of the stove stays cool for ages, and food continues to cook long after the fuel is gone.

And somehow we STILL had time to at least talk about and demonstrate a modern gasification stove (they thought of it as an electric campfire, to play with - reasonable when there are no light sources after the sun goes down), corn cob carbonization (in a stove they burn too slow to be used for high power cooking - too little lignin in them?), and general charcoal manufacture, the use of a bow saw, electric razor, and froe, and hopefully the benefits of a wood splitting platform. We'll all be waiting for more news and photos as Victor, Andreas, Shannon, Rebbecca, and Doba come home - and already there are signs that stoves can be cheaper in the future - we saw a concrete irrigation part that might work, and maybe the brick plant in Viru can make new shapes for these stoves. For me the end result was that I learned again that you can import all the change you want to a community, but you can't make them embrace it. The chances are that they will reject your change - just because it is not what their mothers' did - and your efforts might well be wasted. More on the nature of change as it applies to humanitarian work when I report next... but in the meantime more of my best photos from Peru (both more stoving, and more cultural) are here. And when the Princeton stovers return home there will be more. Going forward I am particularly interested in comparing stove design notes with other groups working on Central and South American stove implementation projects - there are dozens and dozens of us, with just as many stove designs. Let's compare our experiences, and we should be able to deploy better stoves, and more to those who need them most.

to be continued...

1 comment:

vaibhav said...

respected sir
i am vaibhav from india i want to start new indusrtyo f manufecturing of biomass bricks will u plz tell me the what is requiement in the word because there is very huge amount of agro wasrte material in our country so i know i can make very huge amount of product. so plz help me
with regards.

Mr.Vaibhav Balaji Mohale Photonics
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