Sometimes in the autumn of 2010 I was flying from Mumbai to my hometown Guwahati, as usually on the cheapest air-ticket with a tradeoff in having a long looping route, via Kolkata and Agartala. The short stretch between Agartala and Guwahati is actually a quick aerial hop over Meghalaya, which if luck accords, would remain cloud-cover free offering the sight of marvelous verdant mountainsides, steep gorges and snaking brown rivers below. It was during this flight, when thanks to exceptionally clear weather I noticed the scattered pockets of deforestation on seemingly inaccessible hillsides, ones caused not by commercial logging but by the nearby villager’s mundane need for firewood.
I remembered instantly how once as a guest of the venerable T.G.Rinpoche at Tawang in Arunachal Pradesh (another mountainous State with pockmarked hillsides), my host who was a monastery head, yet a simple monk by nature, interrupt our conversation every 15 minutes to get up and feed a piece of firewood to a Bukhari, the ubiqtous cylindrical iron oven found in every house in that region. I noticed that the Bukhari’s gluttonous appetite for firewood was inversely proportional to its thermal efficiency as most of the heat just went out of in smoke. Nevertheless, thanks to the chronically erratic electricity supply, kerosene being both expensive and strictly rationed, the people of cold hilly regions have no way out but to burn firewood to keep warm. Those living in traditional houses use a hearth; others in more modern accommodation are at the mercies of the Bukhari, both extremely inefficient combustion processes.
By the time the flight landed at Guwahati my train of thoughts culminated with me deciding: Why not design a simple lightweight but highly efficient wood burning Stove that could also double as Room Heater and a Water Boiler? "It’s would be definitely easier than stopping people from felling forests, besides who would go up a mountainside to chop down a tree, size it into small pieces and lug it back home as fuel if they had an easier option."So lets just lessen their requirement of firewood with a bit of modern technology and save a few trees in the process. The grand idea of developing a Tree-Saving-Stove seemed quite do-able for an Industrial Fuel consultant whose biggest professional challenges so far were not technical, but in convincing Freebie-hunting clients to pay up or word-sparring with their indignant Foremen who resented the unwelcome monitoring of Fuel usage or not getting their cut for the installed equipment.
The Backdrop
It became apparent at the very onset of this venture, that mine was a case of wanting to re-invent the wheel. Known by myriad names like Smokeless Chula's, Biomass Stoves, TLUD (Top Lit Up Draft) Gasified Stoves and various other aliases and acronyms, there had been hundreds of efforts worldwide by various NGO’s, government agencies, individual tinkerers and even a few Professors in this field. Most of the Indian versions designed by one government organization or another were essentially mud or brick and mortar permanent structures, the Chinese ones focused more of burning coal. Nonetheless, all my attempts in finding a working model or at least anyone who used them proved a failure. Researching the subject online, I learned that several “Biomass Stoves” as they are now popularly known are also manufactured in our country, but even without seeing them or evaluating their performance, the shortcoming of these units was apparent as not only were they atrociously expensive but also relied solely on a specially made Fuel known as Biomass Pellets. Made from compressed sawdust, wood waste or rice husk these pellets were reasonably cheap ex-factory, but appreciate 200-300% in price by the time they reach the retailer filled in a sack and acquiring a Brand name. There are also the Rice Husk Stoves, enjoying reasonable success in commercial establishments, large, heavy and requiring a power source in the form of electricity or a battery to drive a high power fan. Besides the objective was to save trees, where would villagers on a mountaintop get copious quantities of either Biomass Pellets or Husk??
The first step was to decide on the working principle of the proposed Stove, the two rival proven concepts were Gasifier and Rocket Stoves. In the first, the fuel first undergoes Pyrolysis or reduction by extreme heat and low oxygen in a reactor core into a combustible wood-gas which is burned at the mouth of the stove in what is essentially a dual stage combustion process. Gasifier stoves are lightweight, cleaner burning and flexible in terms of fuel, but are of complex construction and if not properly designed didn't’t reduce all the fuel to ash and produced charcoal instead. Extremely popular in Africa, the so-called Rocket Stove on the other hand is a direct combustion design where the firewood is burned at the bottom of a specially made ceramic or other refractory material cylindrical retort. These were much easier to construct but are heavy and could only use firewood as fuel. Thus after analyzing most of the existing designs, their underlying principles as well as their strengths and weakness, and business strategies of the entrepreneurs, it was relatively easy to decide the desired characteristics of my yet to be designed Stove. Achieving it all was a different question altogether. The Objectives: 1. Save Trees by reducing firewood consumption through efficient combustion. 2. Reduce the backbreaking work of chopping and lugging firewood. 3. Design a stove affordable enough for even the poorest people.
The Design Criteria:
1. Burns any Biomass from twigs to coconut and betel leaf stems, wood waste, firewood and even pellets provided they are available.
2. Stainless Steel construction for robustness and long-life.
3. Working on a Gasifier principle to be lightweight have and multi fuel capability. 4. Modular construction for quick assembly.
5. Preferably with no electrical fans, functioning on natural convection.
6. Would not consume more than 2 kg of firewood per hour as most Shoukas(Chulas) in commercial establishments use between 3-6 kg per hour.
7. Should emit the least amount of smoke.
The Prototype( with apologies to Dr.Reed) !!
Not wanting to dive without learning how to swim, I first decided to replicate the simple and popular TLUD design of Dr. Thomas Reed, the father of the gasifying stove. Simultaneously, blending thermo-dynamic calculations with my own experience garnered in the world of Industrial combustion and borrowing few design ques from existing models, my first virtual prototype Stove was soon completed as a CAD file.
The project almost ended before it started on my first attempt in constructing the stove as I went around with my design to various fabricating workshops. They predictably were just not interested in making a one-off piece of a dubious object and got rid of me either claiming overwork or quoting rates high enough to make me think of buying the next cheap air-ticket back to Goa.
Finally, the solution came as a placid realization that Dr.Reed’s stove looked remarkably like a stainless steel vessel where my mother boils milk. Finding a few right sized vessels didn’t seem like a daunting task and I set of on a quest along the alleys of Guwahati’s Fancy bazar, only to strike Gold(Stainless Steel i.e.,) in a shop belonging to none other than a long suffering classmate from school and college. Girish was sporting enough to have me rummaging through his shop trying out various utensils, buckets and containers with a measuring tape. The same afternoon the parental house was filled with screeching sounds of reluctant metal being drilled, hammered, cut and bend. In approximately 3 hours the first prototype, a vague interpretation of Dr.Reed’s concept was rendered to life by two badly deformed Stainless steel pots. An inverted big one with the bottom cut out, a smaller, riddled with lines of holes inserted inside and entire apparatus was blown by a computer fan powered by an adaptor. Collecting a bunch of twigs from the backyard and stuffing the inner pot, (now properly known as the reactor), the first flame in the practical journey of making the “Tree-Saving-Stove” was lit. The twigs initially enveloped by flames quickly converted into smoky gaseous tendrils that lit up into a blaze right above the stove. The translucent flames were bright yellow and the smoke virtually disappeared once the reactor heated up, but most importantly the twigs, which would have burned out in minutes in an open fire, here provided a steady hot flame for more that half an hour. The first effort despite being a pure hatchet job was a successful proof of concept.
Enter the Volcano.
Mid winter, I am back in Guwahati and restart work on my Tree-Saving-Stove after a break of few months. My attempts in continuing the effort in Goa fell flat on the face thanks to various kitchen Utensil merchants in Panjim shooing me out of their stores. This time my purchases at Girish’s comprised a medium sized Milk Canister the kind one sees milkmen lug around or hang on their bicycles and a medium sized Stainless steel bucket. Unfortunately, the dimension of these two were far off the mark from those on my AutoCAD plot, but were the closest available. After a hasty recalculation of the sizes and locations of the various orifices and another two days of screeching metal, the first new Biomass stove of my very own design was ready.
Christened the “Volcano” thanks to its conical shape as much as a tribute to Meg Ryan in the film Joe vs. the Volcano, the new prototype was visually an exercise in simplicity. Consisting of nothing but an inverted bucket with large holes on the side and a lidless milk canister enigmatically sticking out in the middle, without an electrical fan. The objective was to create a gasifying stove that would convert any available biomass like wood chips or twigs into a combustible gas in the oxygen starved high-temperature reactor core and these gases would rise up by natural convection and ignite into flames upon contact with atmospheric air just below the cooking pot. Meanwhile the preheated taxability air would be forced out by the upper holes in high velocity thanks to the geometry of housing, hence eliminating the need of a fan.
The raging tower of flame the Volcano ejected almost immediately during the first trial that same night proved that its was aptly named, but also necessitated a return to the drawing board, in my case the screen of my MacBook pro. The flames were too high and uncontrollable but way beyond expectation for a natural convection stove.
A slight modification in the orifice sizes and the tower of flame turned into a manageable flower of fiery saffron tendrils. The basic design of the Stove even if seriously compromised by the mismatched dimensions of the milk container and the bucket, proved to be a success. A 500gm bunch of dried twigs provided a steady medium sized flame anywhere from 20-30 minutes showing a consumption of 1-1.5 kgs per hour, enough for a small family to cook a meal. Its only drawback was that the cooking utensil had to be removed from the it, if a refill of fuel was needed during cooking time.
The Aftermath
A long professional engagement that brought me back to Goa has me parting from the original Volcano and its couple of siblings in Guwahati. The development on the stoves is now shifted to Goa and as this time as I boycotted the unimaginative utensil sellers, I used industrial processes like TIG welding and made use of Stainless Steel sheets . The effort culminated in the larger EcoBlaze model. Still in an experimental stage and integrating many of the concepts learned from the “Bucket” Volcano stoves these larger units can operate both in a powered (with electric fan) and convectional mode. Build in a modular system, the EcoBlaze comprises of a Gasifier bottom with several interchangeable attachments on top that can converted it from commercially sized Stove into a Water Boiler or alternatively an ultra efficient Room Heater with a chimney. Though the comprehensive thermal and emission analysis of the Stove is yet to be completed, the fuel consumption using some of the worst quality Biomass like Coconut leaf stems and packing wood pieces never exceed 2 kgs per hour. That's a whooping 50-50% economy over conventional clay stoves.
On the whole almost two years after conceiving the visionary plan of a Tree-Saving-Stove, most of the aimed parameters have been achieved. Of course, as of now the prototypes of EcoBlaze only sever the purpose of cooking delicious smoky flavoured curries behind my house in Goa, just like the Volcano & its sibling are brought out by friends and relatives in Guwahati every time there is a gas shortage in town. The next real challenge is to bring the technology to the people who need it the most, but that would be the subject of the next chapter of this story, yet unwritten and maybe narrated a couple of years from now..
Deforestation; caused by indispensable human need for Firewood, an endemic problem of all the mountain areas of India.
I remembered instantly how once as a guest of the venerable T.G.Rinpoche at Tawang in Arunachal Pradesh (another mountainous State with pockmarked hillsides), my host who was a monastery head, yet a simple monk by nature, interrupt our conversation every 15 minutes to get up and feed a piece of firewood to a Bukhari, the ubiqtous cylindrical iron oven found in every house in that region. I noticed that the Bukhari’s gluttonous appetite for firewood was inversely proportional to its thermal efficiency as most of the heat just went out of in smoke. Nevertheless, thanks to the chronically erratic electricity supply, kerosene being both expensive and strictly rationed, the people of cold hilly regions have no way out but to burn firewood to keep warm. Those living in traditional houses use a hearth; others in more modern accommodation are at the mercies of the Bukhari, both extremely inefficient combustion processes.
T.G.Rinpoche, Monastery Head, elected Politician, Friend and Guide.
By the time the flight landed at Guwahati my train of thoughts culminated with me deciding: Why not design a simple lightweight but highly efficient wood burning Stove that could also double as Room Heater and a Water Boiler? "It’s would be definitely easier than stopping people from felling forests, besides who would go up a mountainside to chop down a tree, size it into small pieces and lug it back home as fuel if they had an easier option."So lets just lessen their requirement of firewood with a bit of modern technology and save a few trees in the process. The grand idea of developing a Tree-Saving-Stove seemed quite do-able for an Industrial Fuel consultant whose biggest professional challenges so far were not technical, but in convincing Freebie-hunting clients to pay up or word-sparring with their indignant Foremen who resented the unwelcome monitoring of Fuel usage or not getting their cut for the installed equipment.
The Backdrop
It became apparent at the very onset of this venture, that mine was a case of wanting to re-invent the wheel. Known by myriad names like Smokeless Chula's, Biomass Stoves, TLUD (Top Lit Up Draft) Gasified Stoves and various other aliases and acronyms, there had been hundreds of efforts worldwide by various NGO’s, government agencies, individual tinkerers and even a few Professors in this field. Most of the Indian versions designed by one government organization or another were essentially mud or brick and mortar permanent structures, the Chinese ones focused more of burning coal. Nonetheless, all my attempts in finding a working model or at least anyone who used them proved a failure. Researching the subject online, I learned that several “Biomass Stoves” as they are now popularly known are also manufactured in our country, but even without seeing them or evaluating their performance, the shortcoming of these units was apparent as not only were they atrociously expensive but also relied solely on a specially made Fuel known as Biomass Pellets. Made from compressed sawdust, wood waste or rice husk these pellets were reasonably cheap ex-factory, but appreciate 200-300% in price by the time they reach the retailer filled in a sack and acquiring a Brand name. There are also the Rice Husk Stoves, enjoying reasonable success in commercial establishments, large, heavy and requiring a power source in the form of electricity or a battery to drive a high power fan. Besides the objective was to save trees, where would villagers on a mountaintop get copious quantities of either Biomass Pellets or Husk??
The first step was to decide on the working principle of the proposed Stove, the two rival proven concepts were Gasifier and Rocket Stoves. In the first, the fuel first undergoes Pyrolysis or reduction by extreme heat and low oxygen in a reactor core into a combustible wood-gas which is burned at the mouth of the stove in what is essentially a dual stage combustion process. Gasifier stoves are lightweight, cleaner burning and flexible in terms of fuel, but are of complex construction and if not properly designed didn't’t reduce all the fuel to ash and produced charcoal instead. Extremely popular in Africa, the so-called Rocket Stove on the other hand is a direct combustion design where the firewood is burned at the bottom of a specially made ceramic or other refractory material cylindrical retort. These were much easier to construct but are heavy and could only use firewood as fuel. Thus after analyzing most of the existing designs, their underlying principles as well as their strengths and weakness, and business strategies of the entrepreneurs, it was relatively easy to decide the desired characteristics of my yet to be designed Stove. Achieving it all was a different question altogether. The Objectives: 1. Save Trees by reducing firewood consumption through efficient combustion. 2. Reduce the backbreaking work of chopping and lugging firewood. 3. Design a stove affordable enough for even the poorest people.
The Design Criteria:
1. Burns any Biomass from twigs to coconut and betel leaf stems, wood waste, firewood and even pellets provided they are available.
2. Stainless Steel construction for robustness and long-life.
3. Working on a Gasifier principle to be lightweight have and multi fuel capability. 4. Modular construction for quick assembly.
5. Preferably with no electrical fans, functioning on natural convection.
6. Would not consume more than 2 kg of firewood per hour as most Shoukas(Chulas) in commercial establishments use between 3-6 kg per hour.
7. Should emit the least amount of smoke.
The Prototype( with apologies to Dr.Reed) !!
Not wanting to dive without learning how to swim, I first decided to replicate the simple and popular TLUD design of Dr. Thomas Reed, the father of the gasifying stove. Simultaneously, blending thermo-dynamic calculations with my own experience garnered in the world of Industrial combustion and borrowing few design ques from existing models, my first virtual prototype Stove was soon completed as a CAD file.
A vague replica of Dr.Reeds TLUD designed Stove was the first step.
The project almost ended before it started on my first attempt in constructing the stove as I went around with my design to various fabricating workshops. They predictably were just not interested in making a one-off piece of a dubious object and got rid of me either claiming overwork or quoting rates high enough to make me think of buying the next cheap air-ticket back to Goa.
Finally, the solution came as a placid realization that Dr.Reed’s stove looked remarkably like a stainless steel vessel where my mother boils milk. Finding a few right sized vessels didn’t seem like a daunting task and I set of on a quest along the alleys of Guwahati’s Fancy bazar, only to strike Gold(Stainless Steel i.e.,) in a shop belonging to none other than a long suffering classmate from school and college. Girish was sporting enough to have me rummaging through his shop trying out various utensils, buckets and containers with a measuring tape. The same afternoon the parental house was filled with screeching sounds of reluctant metal being drilled, hammered, cut and bend. In approximately 3 hours the first prototype, a vague interpretation of Dr.Reed’s concept was rendered to life by two badly deformed Stainless steel pots. An inverted big one with the bottom cut out, a smaller, riddled with lines of holes inserted inside and entire apparatus was blown by a computer fan powered by an adaptor. Collecting a bunch of twigs from the backyard and stuffing the inner pot, (now properly known as the reactor), the first flame in the practical journey of making the “Tree-Saving-Stove” was lit. The twigs initially enveloped by flames quickly converted into smoky gaseous tendrils that lit up into a blaze right above the stove. The translucent flames were bright yellow and the smoke virtually disappeared once the reactor heated up, but most importantly the twigs, which would have burned out in minutes in an open fire, here provided a steady hot flame for more that half an hour. The first effort despite being a pure hatchet job was a successful proof of concept.
Enter the Volcano.
Mid winter, I am back in Guwahati and restart work on my Tree-Saving-Stove after a break of few months. My attempts in continuing the effort in Goa fell flat on the face thanks to various kitchen Utensil merchants in Panjim shooing me out of their stores. This time my purchases at Girish’s comprised a medium sized Milk Canister the kind one sees milkmen lug around or hang on their bicycles and a medium sized Stainless steel bucket. Unfortunately, the dimension of these two were far off the mark from those on my AutoCAD plot, but were the closest available. After a hasty recalculation of the sizes and locations of the various orifices and another two days of screeching metal, the first new Biomass stove of my very own design was ready.
Christened the “Volcano” thanks to its conical shape as much as a tribute to Meg Ryan in the film Joe vs. the Volcano, the new prototype was visually an exercise in simplicity. Consisting of nothing but an inverted bucket with large holes on the side and a lidless milk canister enigmatically sticking out in the middle, without an electrical fan. The objective was to create a gasifying stove that would convert any available biomass like wood chips or twigs into a combustible gas in the oxygen starved high-temperature reactor core and these gases would rise up by natural convection and ignite into flames upon contact with atmospheric air just below the cooking pot. Meanwhile the preheated taxability air would be forced out by the upper holes in high velocity thanks to the geometry of housing, hence eliminating the need of a fan.
The first trial of the "Volcano" more suitable for a flare than a cooking pot.
The Flowering Flames of Volcano II , worthy of Meg Ryan herself.
The Aftermath
A long professional engagement that brought me back to Goa has me parting from the original Volcano and its couple of siblings in Guwahati. The development on the stoves is now shifted to Goa and as this time as I boycotted the unimaginative utensil sellers, I used industrial processes like TIG welding and made use of Stainless Steel sheets . The effort culminated in the larger EcoBlaze model. Still in an experimental stage and integrating many of the concepts learned from the “Bucket” Volcano stoves these larger units can operate both in a powered (with electric fan) and convectional mode. Build in a modular system, the EcoBlaze comprises of a Gasifier bottom with several interchangeable attachments on top that can converted it from commercially sized Stove into a Water Boiler or alternatively an ultra efficient Room Heater with a chimney. Though the comprehensive thermal and emission analysis of the Stove is yet to be completed, the fuel consumption using some of the worst quality Biomass like Coconut leaf stems and packing wood pieces never exceed 2 kgs per hour. That's a whooping 50-50% economy over conventional clay stoves.
The EcoBlaze in a natural-draft mode being tested(to cook chicken curry) in the most practical manner!!
On the whole almost two years after conceiving the visionary plan of a Tree-Saving-Stove, most of the aimed parameters have been achieved. Of course, as of now the prototypes of EcoBlaze only sever the purpose of cooking delicious smoky flavoured curries behind my house in Goa, just like the Volcano & its sibling are brought out by friends and relatives in Guwahati every time there is a gas shortage in town. The next real challenge is to bring the technology to the people who need it the most, but that would be the subject of the next chapter of this story, yet unwritten and maybe narrated a couple of years from now..
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