| Boiling Point No. 03 - October 1982 |
The combination of travelling, the ensuing report writing, and the holiday season, have resulted in less activity than usual in the Stoves Project's laboratory and Workshops.
Bill Stewart left Reading at the end of May for Sri Lanka as our Field Project Officer based with the Sarvodaya stove programme in Kandy. In addition, Peter Young, our temporary stove tester, left us in June to work in UN refugee camps in Somalia. Part of the work he did is the basis of the first in a new series of Technical Papers, a copy of which you should receive with this issue of Boiling Point. Our next Technical Paper will deal with optimization of the Indonesian Mein Chong stove.
Ali, our technician, is continuing to make mud/clay samples and testing them on the thermal cycling rig built by Peter. Jon Loose and Jenny Trussell have continued work on ceramic samples testing (see Richard Chaplin's article, page 3, on this subject).
Jon has also embarked on a series of tests on 5 ceramic stoves. Results for the first stove, the Magan Chula, are summarized on page l5 . Initial results for the ITDG double-skin ceramic stove have given PHU2 values of 30%.
Stephen Joseph paid a second visit to Kenya in June, as a result of which the ITDG Stoves Project is now officially collaborating with the Kenyan Ministry of Energy's stove programme. At the time of writing, he is in fact in Kenya again, together with Bill Stewart who will remain for several weeks after Stephen leaves. While he is in Nairobi Stephen hopes to participate in an IDRC Workshop on Fuelwood Energy.
Stephen will leave Kenya for a consultancy visit to Nepal, to evaluate the progress of the FAO/RECAST pilot stove programme. Since this visit was planned, the news from Nepal is that demand for the new stoves exceeds supply.
P M Chiplonkar
Herman Johannes, Jon Loose
Pam & Ray Pomfret-Stewart
Bill Stewart, Jenny Trussell
(Readers wishing to enter into correspondence with any of the authors may obtain full postal addresses from the Stoves Project address given opposite)
'Boiling Point' is the newsletter of the Intermediate Technology Development Group Stoves Project. Contributions are welcome in the form of articles of not more than 700 words with line drawings, simple graphs, etc. where appropriate. Copy date for the next issue is 1st December 1982.
All correspondence should be addressed to: 'Boiling Point', ITDG Stoves Project, Applied Research Section, Shinfield Road, Reading, UK, RG2 9BE.
Yvonne Shanahan attended thereto Forum at Marseille organised by GRET - GERES, and contributed- to a draft field test procedure' and development of a strategy for the large scale: dissemination of stoves. One 'result of this Forum is a VITA Workshop meeting planned for December on performance evaluation for improved, fuel-conserving stoves, which Stephen and Yvonne hope to be attending. It is intended that a document on test methodologies is prepared as a result of the workshop, to be published and widely disseminated.
Yvonne is to make a consultancy visit to the Gambia, to help launch the National Stoves Programme.
Jenny Trussell has been making the ceramic stoves for the testwork programme, preparing training materials, and a display poster for the September 'BIOMASS' conference in Berlin at which Stephen presented a poster paper.
Mr P. M. Chiplonkar, (working for the Indo-German Dhauladhar Project, Palampur, India), spent two weeks at Shinfield on a training course to cover areas of the Stoves Project relevant to his own work. Mr Chiplonkar has contributed an article on his experiences of stoves extension work (This page)
The area covered by the Indo-German Dhauladhar Farm Forestry Project (HP, Palampur, North India) is about 350 sq km. Population 30,000 (GR 30% in 10 years) in 102 villages. Altitude 500 to 4,500m. Rainfall 2,500mm pa, falling mainly in Dec-Jan and July-Sept. Farms are small and the land is worked up to high altitudes, adding to soil erosion. Many: of the men work in road building gangs as the agricultural production is sufficient for only 4 months of the year.
The project is working in forestry (planting fodder and fuelwood species); animal husbandry improving breeds and management); agriculture; horticulture; and alternative -technology which is concentrating on fuelwood saving stoves.
Houses are built of stone and mud on two storeys, with a slate roof. The kitchens are found on the first floor so that smoke can escape through gaps in the eaves of the roof. The existing stoves are chimneyless with two or three pot holes and are made from mud at no cost by the women.
Nearly all fuelwood is collected, not purchased. For the long-term, fuelwood trees are being planted around the villages, but for now, efforts are being made to introduce fuel conserving stoves. The design chosen was the New Nepali Chulo, one of which was installed in a house in December 1980. The household used the stove all the time for two months, but complained that the stove did not provide enough personal heating, and objected to the increased work required as the wood had to be cut into small pieces for the stove to work efficiently.
Three months' development work followed to improve the Nepali Chulo and modify it to suit local conditions. It was decided to utilise the village motivators as extension workers. Demonstration units were made in the schools and in the homes of most of the motivators, after they had been trained in construction. Five families were asked to cook alternately on their old and new stove. From observations made it was found that the new stove was able to save more than 40X fuelwood, cook faster, keep food warm for about 5 hours, and get rid of troublesome smoke from the kitchen.
The village motivators were to motivate the people, construct the stoves, give instruction on its proper use, and report regularly on the stoves' condition. After 50 stoves had keen made and installed a survey revealed that most of them had not been constructed correctly, and the owners had not been given adequate instruction in the use of the stove. The rate of stove building was slow - the motivators complained that they had too much other work to do besides building stoves.
It was decided to employ people as professional stove builders who visited the villages in turn, building several stoves in each. In this manner about 350 stoves had been--built by +March 1982.
During this period the motivators were responsible for reporting on the condition and usage of the stoves and the reactions of users. However, in April 1982, a survey revealed that many stoves were in bad condition, improperly used and not saving fuel - some even reported that more fuel was needed. Users complained that their dissatisfaction with the stoves was being reported to the motivators, but the information had not been passed on.
As a result, from May 1982, the stove constructors were asked to visit the users regularly to educate them in the proper use of the stove, to repair the stoves where necessary and to build another if the first stove was irreparable. Out of about 500 homes with the new stove, 70 needed a new one, but 10 of these households refused to have another mainly due to irritation over the earlier lack of follow up. Most of the bad stoves had been built incorrectly, in some cases the mixture had not been made properly, or not allowed to set for the required period of time, or some other hurried improvisation made.
Coming up to date, most people are aware that the project is installing new stoves by subsidy. Motivating people to request a new stove is no longer a problem. It has been established beyond doubt that the new stove is an improvement when properly built, used and maintained.
Based on our experience, the strategy for stove building in future will be as follows:
1. Village motivators will collect the names of interested people, inform the stove constructors, and with them decide the date on which they will come to guild the stoves. The village motivators will supervise the preparation of the mud mixtures in good time for the date.
2. The stove constructors will make the stove block on the given date, and will be responsible for returning to the village when the blocks are dry enough to do the cutting and to fix the accessories (which are stored by the motivator). The stove constructors have supervisors in attendance for the cutting process.
3. After the stove becomes operational the constructors visit the households twice a week until they are satisfied that the stove is being used properly; then every fortnight the supervisors will visit the household for a period of two months.
4. The motivators report fortnightly on the condition of the stoves to the Extensio Section while the stove supervisors give weekly report to the Energy Section ofeach of the stoves in their area. This way reports can be cross checked and mistakes made in the past will not repeated.
P M Chiplonkar Palampur, HP, India
Included in the ITDG Stove Programme is E study of the materials aspects of ceramic stove design and construction. This work has entailed a consideration of alternative types of materials, their most appropriate form and the means by which they may be evaluated. Clearly full comparisons between specific materials cannot be made independently of design considerations: shape, size, type of fuel etc. However, it is reasonable to identify in general terms the critical properties for stove applications, of . given type of material, for use as a basis for comparison.
The low cost and availability of raw materials and skills make fired ceramics an obvious choice for this application. However their susceptability to impact damage, thermal stress and thermal shock are their major limiting factors. This area has been the principal focus of attention in this study.
The main difficulty has been the lack of an appropriate test which would give a reasonable indication of merit. Because of the combination of material properties which are involved, it can be argued that ceramics which show good resistance to thermal shock (rapid cooling or heating) would also be resistant to thermal stress (slow temperature cycling) and mechanical impact too.
In seeking a test method to establish thermal shock resistance we were conscious of some specific requirements:
1) The method should be relevant to the stove application, i.e. shock from temperature levels such as experienced at the surface of stoves, samples of appropriate proportions and direct assessment of shock effects.
2) The method should be fairly simple, being easy to reproduce and not requiring highly trained investigators.
3) It should not require sophisticated or expensive equipment that could not be readily purchased or manufactured anywhere within reason.
4) Results should be quantitative and reproducible so that comparisons may be made between results obtained from different laboratories.
5) Low cost.
At the outset a direct shock method was considered essential. 400°C was taken as the highest realistic temperature that might be expected on the surface of a ceramic stove, and was therefore taken as the temperature from which to shock samples. To achieve a severe shock samples were plunged directly into a bucket of cold water (20°C-25°C). To minimize variation an extrusion method has been chosen for sample manufacture. m e die geometry is shown in Fig 1, the length of samples being about 85mm.
Exploratory tests showed that simply shocking samples even thirty or more times did not by itself cause fracture, but did induce surface cracking. A residual strength test (measuring the loss of bending strength resulting from shock treatment ) would register this type of damage, but would introduce too many problems in terms of the equipment needed and the interpretation of results. So we went for a 'residual impact' test involving a simple measurement which would be a reflection of the toughness of the material as well as the severity of the surface cracks.
The impact test we have adopted uses a light pendulum as the means of subjecting a simply supported test piece to repeated blows of gradually increasing severity. The fracture energy recorded is the energy of the impact which finally causes fracture. The method is open to criticism, especially as to the effect of repeated blows; however, results obtained to date are significant and repeatable.
The way we have used the test to assess the thermal shock resistance of a particular clay mix is as follows. Take a batch of between 12 and 24 test bars, subject half to the test as they are and subject the remainder to the test after 20 shocks from 400ºC into cold water. With this approach, the before and after measurements are of the same form making comparison straightforward, both between shocked and unshocked samples as well as between samples of different materials.
Fig 2 shows the apparatus we have used. Note the twin suspension strings and cylindrical weight (about 100gms to give increments of impact energy of about 10 Joules for each 10mm of height). To check pendulum height at release we use a rule taped to a weight and a solonoid from an old Post Office relay for smooth release.
Some results with an indication of scatter are shown in Fig 3. For the red clay used, an increase of firing temperature from 800°C to -900 C is obviously significant. Wood ash, though a beneficial additive for impact resistance, is no help when it comes to thermal shock, while the samples containing sand (here one third of the total volume) are unaffected by shock.
Another useful test which is also fairly simple -to perform is the measurement of apparent porosity. Apparent porosity is the volume of open voids in a ceramic sample as a proportion (usually a percentage) of the total volume. For a given clay body, as the firing temperature increases, the degree of vitrification increases and porosity tends to fall to a minimum, however it can, of course, be dramatically affected by additives. Cur work to date suggests that while high porosity is generally a good thing as far as impact is concerned, it has a bad effect on thermal shock resistance, most probably due to the effectively increased heat transfer resulting from the penetration of water into the open surface pore structure.
Apparent porosity is found by weighing a dry sample (Ml) and then impregnating the voids with water, either by prolonged boiling or preferably by vacuum impregnator. The sample is then weighed submerged (M2) and finally weighed wet but in air (MB), the apparent porosity (AP) is given by:
AP = (M3 - M1)/(M3 - M2)
It is hoped that simple tests like these can be used by workers in different parts of the world to assess quantitatively the merits of some of the traditional methods, and maybe some novel ones too, for producing low cost refractories. Results may then be given wider circulation for the general enlightenment (or confusion) of all.
Richard Chaplin - University of Reading
When designing and introducing ceramic stoves as a new product for local potters, certain customs or taboos concerning divisions of labour have to be taken into account for the project to become a success.
In many places there are distinct taboos on who does what in the process of making pots. For example, in Ghana it is taboo for men to make the pots and touch the unfired clay for fear of causing infertility in their women. In Java the women who make the local 'Grabah' domestic wares, rarely take part in agricultural work because they believe that their pots will crack in firing if they work on the land.
Divisions of labour have evolved through other ways than sexual taboos, a good example being the wood collection for the firings in Java. Men collect the fuel for the pottery firings and in turn, because of this, they are also in charge of the firings. The methods by which the men carry their wood enables them to collect more than women and sometimes they can make two collections in a day even though the wood is quite some distance away. The men traditionally carry wood strung from a pole across their shoulders (a Pikul) or else they have a bicycle with a side cart. The women traditionally carry their loads in a 'Gendongan', a sling which rests on the hip or across the back, and are not able to bring back such large pieces of wood for the firings with this method.
In the Addis Ababa region of Ethiopia the men fire the pots, purely because it is considered too hot for the women to tend the firings. As this is not based on a sexual taboo it is often broken, especially if there is not a responsible male to take on the task.
The effects on the social structure of the potters is an important consideration in ceramic stove introduction, especially as the divisions of labour could be changed to such an extent that one of the sexes may be distinctly worse off, losing the benefits of co-operation as one partner finds a new found wealth in pottery stoves.
An example of change in the pottery industry which has affected the women in the Kasongan area of Java is described. Here, both sexes equally share in the mining, collection, and mixing of clays, divisions of labour occuring in the making and firing of the pots. The women are solely responsible for making the 'Grabah', the domestic ware which is traditionally thrown on a slow wheel. The men never use this technique as they are derided and teased by others if they do so. The men make toys and the clay animal-shaped money banks, increasing production around festival times. Most of the time, however, they spend in collecting and preparing clay, collecting fuel and firing the pots (the latter for which they were solely responsible). The women rely heavily on the men in the household in order to produce the maximum amount of 'Grakah'. Indeed, if a woman had no competent male's help available she would take her wheel into the yard of a neighbour whose husband would take on her labour requirements, being paid half the sale monies in return.
In the early 1970s, life and income began to change for the women 'Grabah' makers for two reasons. Firstly, there was an influx of metal and plastic wares at competitive prices on the market. Cooking pots formerly of clay could now be bought in - aluminium and would last longer ; plastic jugs replaced traditional clay ones. Women with no other skills available found themselves working at far below their capacity production. Secondly, the men were introduced to new skills. A new decorative technique called 'Urkir Tempel' - the art of applying clay in a decorative fashion, in this case to the traditional animal banks, was introduced by a former Kasongan potter who had been away for sponsored training. These new Kasongan figures immediately attracted attention and began to sell fast. Men who could make the figures quickly acquired higher status and others began to follow suit. Tburists bought the figures and prices rose. In 1978 a man making 'Ukir Tempel' figures made around 22,500Rp a month. The women 'Grabah' makers made only around 2,500Rp a month. m e main households producing these figures began hiring extra male labour to increase production. If the demand for the figures increases (and this seems likely as they are very attractive works of art and the tourist industry is booming), the women will be left, not only with a declining income, but without the male labour needed to assist them to make the few 'Grabah' still needed.
There are lessons to be learnt from this situation, indeed, the time might well be right in Kasongan to introduce wheel thrown pottery stoves to balance out the inequalities which have arisen. One thing the Kasongan potters' example does highlight is the need to assess in full every impact which the introduction of ceramic stoves will make on the local people; not only on those who will cook on the stove and on those who were perhaps making stoves before, but also on the delicate balance in the divisions of labour between the potters themselves.
Biochar may be obtained by burning biomass (leaves, grasses, weeds, or agricultural wastes) in an open or partly closed kiln. The kiln may be a drum, an earthen pot, a trough of brick and mud, or a pit in the ground. Some 10kgs dry biomass are put into the bottom of the open kiln and ignited. When the temperature has reached about 500°C, the kiln should then be filled with biomass and its mouth partly closed with a heat resistant plate. The emerging pyrolitic smoke will expel air from the kiln and prevent air from entering it and burning the glowing char to ash. When all the biomass has turned to char, the smoke will thin out even if a stick is stirred within the kiln. At this stage water should be poured into the kiln to extinguish the fire. The wet biochar is taken out of the kiln and processed directly into brazier briquets, lump briquets, or cartridge briquets.
No glue is needed to make these briquets. They may be moulded with biochar containing 30% sawdust or rice husks. Bamboo or wooden sticks are put through the base-holes of a traditional clay brazier. Wet biochar is pounded in E mortar to a dough and then compressed into the space between the sticks in the brazier. The sticks may be pulled out within an hour leaving canals running through the casted briquets. After drying the brazier briquet for at least 7 days if the sun, it may be burned for cooking or heating.
The brazier briquet is fired by burning biomass underneath it or on its upper surface. When one canal catches fire then eventually all the canals will become incandescent with a temperature of 700°C. The briquets should burn with practically no smoke or odour. The brazier briquet is considered energy efficient because the convection and radiation is in the upward direction only, while heat isolation by the char at the briquet's periphery reduces conduction losses. The calorific value of this biochar is 5,000kcal/kg.
Lump or Cartridge Briquets
Burning 10kg dry biomass will yield 3kg biochar. To make lump or cartridge briquets a dough is pounded from dry biochar and 5%v tapioca glue, or from wet biochar with 2.5% cement, or with 12.5% fresh leaves from a variety of plant families with sticky saps, like legumes, Hibiscus, Euphorbia, etc. The dough is then compressed in a mould to lump briquets of different forms or to cylindrical cartridge briquets with a number of canals.
Spherical biobriquets may be made without any tool by compressing the dough with one's palms and fingers into balls. Cylindrical briquets 3cm in diameter may be made by compressing the dough with one's thumb in a bamboo or plastic tube. A bisquit tin 15cm high and 14.5cm across with 9 holes 10mm wide punched in its bottom, and 8 holes near its mouth may be used as a mould to cast cartridge briquets, or as a brazier for burning them. The mould's wall is lined with a metal or plastic sheet, then sticks are passed through the nine holes in its bottom and dough is compressed into the space between the sticks to a height of 13cm. m e sticks may be pulled out within a few hours and the cartridge dislodged within a few days. The mould without its lining may be used as a brazier when placed on three bricks, loaded with a dry cartridge and fired. Combustion gases will escape through the 8 holes near the mouth of the brazier when a cooking pan is placed on it. A more durable brazier for burning cartridge briquets could be made from cast iron.
Burning dry biomass to biochar reduces its calorific value by about 55%. The energy lost is for a considerable part carried away by the combustible components in the smoke like hydrogen, carbon monoxide, methane, methanol, acetone, acetic acid, tar and carbon particles. A stove burning biomass or wood together with its smoke and char will be an efficient stove, and some traditional stoves like the 'rag' on the islands of Savu and Roti, for cooking palm sugar, do just that. This stove of mud, which is partly underground, commanded the admiration of Captain Cook, who visited those islands when he discovered Australia (1). Combustion in the stove takes place in a closed space. Heat loss through convection, radiation, and conduction is minimal and very little smoke escapes from the stove.
Smoke will also burn in a hybrid stove which comprises a brazier briquet on top of a wood or biomass stove of the same diameter and height (Fig 1). A biobriquet is cast in its upper compartment and fired. When biomass is burned in its ash compartment then the smoke will ascend through the glowing canals of the brazier briquet and flare away. m e heat generated in the hybrid stove is the combined heats of combustion of the biobriquet, the wood or biomass, its smoke, and its char.
(1) Fox, J.J.: Harvest of the Palm, Harvard Univ Press, 1977. p 124,
Energy Studies Centre
There is presently a need to utilize all existing fuel resources to minimize the demand on traditional fuels. The situation in developing countries is rather grim where wood is used by the majority of the population for cooking and reserves are dwindling rapidly. In addition, other factors which emphasize the need to develop cookers using other fuels are:
- the increasing costs of traditional fuels;
- the large amounts of other potential fuels available,
- the high demand for low grade heat for cooking;
- the relatively tedious method of cooking with traditional fuels;
- the high level of smoke generated by traditional fuels.
Considering the above, the author has studied methods of using waste material as fuel in many rural applications. This paper discusses a cooker using sawdust as a fuel.
Design Features of the Cooker
The cooker is made of galvanized iron 0.16cm thick. The dimensions of the cooker are shown in Fig 1. The two galvanised iron handles are riveted to the body of the cooker, as are the three base stands. The removable top cover is shaped so as to direct the hot gases on to the base of the cooking pot. The base plate has seven holes l.9cm in diameter and spaced 6.4cm apart between centres. This configuration, deduced from earlier work, provides for the use of a minimum mass of fuel, high heat production, and minimizes the material used for constructing the cooker. The base plate rests on one of three racks: thus various heights of packed fuel can be achieved. The cooker can be made with simple tools, such as a chisel, hammer and rivets.
Use of the Cooker
The fuel should be in solid particles that are suitable for close packing. Sawdust has been used in initial tests. Before loading the cooker with fuel, rods (of a slightly smaller diameter than the base-plate holes) are inserted through the holes, and the sawdust packed around the vertical rods by hand; it is not necessary to use much force or any binder to keep the particles together. The rods are then extracted, leaving holes through the fuel.
The fuel can be lit by sprinkling kerosene around the top of the holes and then applying a flame, or simply applying a flame under the base plate to the holes, so the fuel burns upwards. Alternatively bits of paper inserted into the tops of the rod holes, and scattered over the surface, can be lit to ignite the fuel. Start-up time is usually 3-10 minutes which is faster than many traditional cookers.
After lighting, the pot is placed on the supports which keep it 1.25cm and 3.8cm above the top of the cooker and the burning surface of the fuel respectively. Heat lost from the hot gases is therefore minimized and adequate combustion is produced by the air entering the bottom of the cooker.
When loaded to maximum height the cooker holds about 1.7kg of sawdust, and depending on wind conditions can burn for up to about 4 hours. Using a packing height of about 5cm and the 7 burner holes, it consumed in tests about 0.65kg of fuel in about 3 hours. The heat produced depends on the number of burner holes and the height of fuel used so the cooker can be adjusted to the needs of the user. For general use for up to 4 hours it is recommended that the cooker is loaded with the base plate in the lowest position, using all 7 burner holes. For cooking periods of 2 hours or less the base plate should be in the centre or top position. In all cases the sawdust should be packed to the top of the cooker.
Under use the cooker has been shown to have an average efficiency of about 15% over the period of burning. Loading is simple, and once lit, the cooker does not have to be tended as the fuel burns well throughout the cooking period. In practical use it is found that, in about three days, the user can learn to assess the depth of fuel and number of burner holes required to give particular cooking times, and therefore avoid waste of fuel.
An advantage of this cooker using sawdust is the negligible amount of smoke produced, which is only visible during the first few minutes until the burner holes burn with a red glow.
Work on this cooker is being extended to utilise all possible forms of waste material. It is also necessary for other traditional fuels to be used in order to minimise the rejection of this cooker by the would-be users. Various materials can be used for construction and further work is in progress to consider those which will reduce the dependence on imported materials.
Several demonstrations have been made of this cooker in Sierra Leone. There is keen interest shown by many people, and some have fabricated their own models. However, certain design guidelines must be adhered to in order to reduce fuel wastage, improve efficiency, reduce smoke production and minimize accidents. A popularizing programme will therefore have to be carefully initiated so that effective use is made of the present cooker design.
University of Sierra Leone
ITDG is working in Sri Lanka with the Sarvodaya Shramadana Movement to introduce improved stoves into rural areas. The project is based in the Kandy district which is one of the hilly wet zones situated in the centre of the country. Earlier this year, a baseline survey was carried out in various of the project villages. Each village was selected to represent a village type. This was defined on the basis of the village's history, spatial location, ecology and rousing. The objective was to see if there were any consistent relationships between these easily determined factors and the probability of a strong latent demand for new stoves.
In this article we outline these four village factors and indicate their probable influence on household fuel supply and kitchen systems.
1 HISTORY OF VILLAGE
Possibly the simplest and most influential characteristic by which to differentiate between villages in the same area and from the same culture is its history. Traditional villages were established on sites for good ecological considerations, i.e. access to fertile fields, water, building materials and fuel. They have had time to accumulate, use, or re-invest wealth when it has been produced. Social organization will have developed with a degree of social and economic stratification. New villages, which are often called colonies, are usually inferior in all respects.
Traditional villages are usually in the lower hills and valleys and border on other villages. Most of the houses have a good homestead plot around their house. Population increase has reduced the size of homesteads and agricultural land so that they are insufficient to support the population, but they usually have better access to roads and facilities so they have more chance to gain non-agricultural employment. Casual labour jobs are usually easier to find than in the more isolated new villages. Outside resources are more readily available and above subsistence wages are more common. Social stratification is strong, but the importance of the village power structure is reduced, owing to the integration of the village into the whole district economy and political system. Access to fuel and other resources is quite variable, according to the land holdings and resources of the household.
New villages were created in the last 50 years to meet the demand for more homestead and agricultural land. The land is usually of poor quality and both the homestead and the agricultural fields are not especially productive. Extra income from casual labour is often more difficult to get because of poorer access to places of employment. The fuel supply is less commercialised because there is less economic demand. The village has less social stratification and traditional power structure. Villagers are more responsive to outside help, but have less ability to organize among themselves.
2 SPATIAL LOCATION OF VILLAGE
Almost all of-the Kandy district is hilly, but how much ' end what type of agricultural land there is, the access to water, roads, and fuel sources varies greatly from village to village. From the point of view of fuelwood availability the most important parameters are the average land holding or population density and what fuel resources surround the village. m e spatial locations of the villages are classified as village on village, village on tea estate, or village on forest.
Village on Village
This type of arrangement is common in the lower hills. Agricultural fields interfringe the highland on which the homesteads are placed. It is difficult to see where one village stops and another starts. Villages have expanded and new villages or colonies have been created. The density is quite high and does not vary much from village to village of this type. This kind of village is probably the commonest type in Kandy district.
Fuelwood sources within the village and immediate vicinity are the homesteads and the small parcels of private forests and crown land. Fuel is brought in from local forest land by local vendors and from the rubber estates and the dry zone of Sri Lanka, by larger commercial operators in lorries. It is important to note that what may look like a forest from a distance is often a densely populated village, underneath a cover of tree crops. These tree crops form the homestead and cannot be cut down for fuel because they provide other benefits such as' fruit, spices, shade, cattle feed and fertilizers.
Village on Estate
At higher elevations many villages are bordered by tea estates. m e village usually occupies the hollows and the valleys, and the tea estates cover the hillsides. Population growth has reduced any buffer zones between villages and estates that might once have existed, so the villages often border right on to the estate. In some of the steeper parts, forests still exist but they occupy little of the total land. Per acre, tea estates produce less usable fuel than highland Homesteads, and the production is seasonal when pruning or replanting is being undertaken. The homestead, the clippings and roots from the tea estates, and wood from more distant forests, are the main sources of fuel. The amount of commercial wood brought by vehicle is less, due to the greater distance from the main roads. m e demand for commercial wood is also met by people who travel into the forest and sell wood by the head load.
Village on Forest
The village on forest location is usually fairly remote and on steep or high land. Most forest is owned by the government. The forest as a source of fuel can be a heavily degraded unpatrolled forest, a slightly degraded forest with no patrols, a closely guarded forest from which only dead wood can be removed, or a forest from which nothing can be taken. Degraded forests are the most common in Kandy district and offer sufficient amounts of wood for the scattered households. These are the least numerous type of village.
3 ECOLOGY OF VILLAGE
The closest source of fuel for people is the produce from their own homesteads. This includes dead coconut branches, coconut husks and shells, pruned branches from smaller trees, large branches cut off larger trees, cuttings from fences made of interwoven trees, and other burnable organic debris. At least an acre of well-developed homestead would De needed to supply most of the cooking needs of a family. Besides the size of the holdings, the maturity and quantity of the trees also determines how much fuel will be produced. The quality of the village homesteads may be rated as good, medium or poor. The poorer the quality of the homestead, the more fuel that must be obtained from elsewhere.
The homesteads are usually on rolling highland with reasonably good soil. Many types of trees are planted and are growing well. A substantial amount of usable biomass is produced throughout the year.
The homesteads are surrounded by some trees, but owing to poor soil, lack of water, or immaturity, they do not produce a cover and can only De considered a supplementary source of fuel.
The homesteads are on nearly barren ground, except for some ground plants. There are few, if any, trees planted. Usually this is because the homestead is quite new.
4 HOUSING IN VILLAGE
In Sri Lanka housing is the most consistent indicator of wealth. A rich household will usually have a cement floor, brick walls, and a permanent roof, whereas a poor household will only have a mud floor, mud walls, and a thatched roof. Model houses built in government housing schemes are made of cement, brick and asbestos roofs, but are often smaller than mud houses and are not as high quality housing as owner-chosen cement/brick houses. Since they are given to poor people for a small monthly rent they are not a true measure of wealth. However, they are important in terms of new values to make a cleaner more 'modern' kitchen. Villages where the houses were built by the owners and not the government, will have a range of house types according to wealth.
me village has many large houses often with cement floors and permanent walls and roofs. The large houses may also be mud with tile roofs. Since most landowners are deficit farmers, large houses can signify outside sources of income (non-agricultural) and greater commercialisation of inputs ' such as food, fuel and building materials. If the wealth is based on agricultural production it also means there will be extra money to purchase other luxuries.
A majority of the houses are small mud houses with cadjan roofs. Sufficient agricultural resources are not available so casual labour is the main source of income. Food is often bought out of necessity for much of the year, but fuel and building materials are usually collected by the householders.
These houses have been built in government housing schemes, based on very small designs. The house and a quarter acre of homestead, or less, were given to poor people. No room was given for a kitchen, so most people have built on an extra room or patio. When they have the money there is a strong interest in an improved kitchen and improved stove. Rented houses in trading towns are similar to government housing in that they are small, but made of brick or cement.
In the next edition of 'Boiling Point' we will continue our report with a case study of a Kandyan village and an overall look at the implications for Extension of new stoves in Sri Lanka.
Pamela and Raymond Pomfret-Stewart are Peace Corps volunteers based in Tenkodogo (Upper Volta) working with a modified Kaya concrete stove and the chimneyless Tungku Lowon model (see photograph). To aid promotional efforts they have commissioned a local artist to produce a series of paintings on cloth, which they use in teach-in sessions, to 'sell' the stove to villagers. After a year's work they are beginning to receive enthusiastic response from the inhabitants.
Drawings adapted for printing from photographs of originals
The Magan Chula Stove was originated by the All India Village Industrial Association, Maganwadi, Wardha, India, and subsequently improved (in 1955) at the Gandhiniketan Ashram near Madurai, who developed the portable model which we have recently built and tested at Shinfield.
The stove is well established locally and current production is estimated at 100-200 per month by the Ashram potter. We do not know whether the stove is being produced elsewhere. There seems a good chance of it having caught on in the 30 years or so of production. Approximate costs are:
Rs 7.50 18cm diameter stove
Rs 1.00 30cm chimney
Rs 2.50 Chimney cap
It is a ceramic stove which is built, in component sections, by skilled potters and put together in the kitchen then covered with earth. The e earth acts as an insulator and fills any gaps between the pottery sections. This means that the inside of the stove stays hot and the outside stays cooler. As built in India, the stove has pottery or asbestos chimney sections. We used a 7.5cm diameter asbestos chimney, 2 metres high. The stove was briefly described in the ITDG Compendium of Tested Stove resigns (1980). The Percentage Heat Utilised (PHU) was quoted as being 12X for this stove, however, the original ITDG-built model of the stove was copied from inadequate drawings and more recent work has indicated that when built correctly it is capable of up to 22% PHU.
The results of the Shinfield tests are as follows. Initial PHU2 values of 17% were obtained in Standard tests but wet wood (40% dry weight basis) and large wood (6cm x 3cm c-s) tests showed efficiencies were improved to 20-22%. Accordingly the stove was improved for the standard conditions by decreasing the undergrate air flow and raising the baffle under the back pot. After these changes, PHU2 was increased to 20% for standard tests.
The alterations to the baffle and air duct changed the PHU without affecting the power output of the stove, presumably by slowing down the draught and releasing more heat to the pots. Observations through heat-resistant glass dishes confirmed that the flame pattern was improved.
A look at the graph of Power v PHU2 shows that the unoptimised stove tended to work less efficiently at high power. It also emphasised the flat response to power of PHU with this stove. This indicated a good stove for the user who may have to burn various fuels.
Although no cooking tests were carried out, the stove was very serviceable and easy to use during the water boiling tests. Most of the smoke was removed by the chimney. It burned Iroko (a dense wood and normally quite difficult) very well, wet wood quite reasonably, and gave very good average PHU2. Based on these findings it is a stove well worth consideration.
(Summary of a forthcoming Technical Paper)
Newsletter of the Intermediate Technology Development Group Stoves Project at the Applied Research Section, Shinfield Road, Reading, Berks, RG2 9BE, UK
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