| Boiling Point No. 08 - December 1985 |
|REVIEWS AND SUMMARIES|
By R. Louvel, Association Bois de Feu 1985.
This is a half way stage report (16 pages in French - for the Niger Ministry of Mining and Industry) of the project for the design, production and promotion of domestic cooking stoves to burn groundnut shell briquettes.
The report sets out the justification, aims and programme of the project and its implementation up to the stage of trials with 70 families and the first set of results. The stove was designed and lab tested in cooperation with ITDG showing a PHU (Percentage Heat Utilization) of about 30%. Louvel then field tested and optimized the design in Basso, Niger. It is a relatively simple, sheet steel stove ("Brini" see Figs. 1 and 2) with a grate, a conical combustion chamber, a fuel passage and a cylindrical outer wall, designed to give a close fitting shield to a particular size of pot.
The 'Brini' is a modification of the 'Mad Sauki' woodstove (See BP No. 7). The addition of a combustion chamber helps keep the briquettes in closer contact and improves combustion. Minor field modifications reduced smoke and facilitated lighting with only a very small reduction in PHU. Louvel reports that the standard boiling water test procedure for wood stoves needs to be modified for briquettes to take account of the difference between the value of wood charcoal and of briquette "charcoal".
Some experiments were made with a similar stove but with a mud combustion chamber. This showed almost no improvement in PHU but was much more stable and was considered to be sufficiently attractive to justify development.
The Brini stoves were made in 3 sizes to match the most popular pot sizes. A group of blacksmiths were given 2 weeks training to make the stoves and were later found to be making good stoves but were too slow to be economic (hammer and chisel method with templates) Louvel estimates that the 'Brini' No. 3 size could be made for about 900 Fr CFA (£1.50), compared with 700-750 Fr for the standard 'Mad Sauki'.
The project is now considering the merits of continuing to develop the briquette stove as compared with encouraging the use of burning briquettes and wood bagasse in existing stoves. The latter would be an interim solution whilst wood is still available and would meet the situation where either fuel might be temporarily unavailable.
The present, actual briquette production is very small in Niger, 3-400 tonnes per year, mainly because of high prices and lack of a local distribution system (22 Fr/kg compared with 10 Fr/kg for wood in Dasso). The current production capacity of Sonara (groundnut de-shelling plant in Dasso) is also small at 2800tonnes per year. Smaller semi-mechanised or manual presses may need to be explored to match local production and use. The main problems of use were feeding too much fuel at once and not cleaning out the ash after each use.
Although the initial survey results were favourable, Louvel considers the small numbers surveyed and the simple procedure do not justify firm conclusions.
The report concludes with a series of questions which need to be answered in the final evaluation. This should provide useful indications for the several countries also investigating the use of agricultural residue briquettes for domestic cooking.
National Stoves Project, Department of Community Development, Gambia
This is an It page English language booklet prepared specially for National Womens Week, 19 - 26th April, 1985. During the week the stove project team travelled the country, arousing considerable interest in new stoves and fuel conservation. Contact was made with womens groups and demonstrations were given on the range of improved stoves by cooking traditional meals in market places and at gatherings of women where participation was welcomed. The aim was a promotional marketing exercise to show as many women as possible that new stoves are available which conserve wood, burn peanut shell briquettes, cook more quickly and are safer and more durable.
The booklet briefly describes the development of the programme and the stove designs and outlines the expectations for the future. For example, metal and ceramic designs will be promoted on a commercial basis with training, marketing and technical back-up from the project.
The stove designs presented and illustrated are the all-metal 'Noflie' which burns wood and briquettes (see BP. No. 6); portable pottery stoves for wood and briquettes, the shielded fire mud stove (Kumbe Gaye) with and without a pottery liner; and large brick stoves for bigger households and institutions.
By G. Campbell, K, Dhakal, S. Joseph, K.L., Shrestha and K. Sulpya.
As part of the evaluation of the Programme FAO Stage I Stoves in Nepal a series of tests were carried out in June 1984 to assess the possible reductions in fuel consumption and levels of smoke emission.
The authors had previously noted that in houses where ventilation was poor, a person's eyes would start to water very soon after entering a house that had an open fire (agenu) or a semi circular mud stove (chulo). In houses that were better ventilated the time before the eyes watered was increased to approximately 5 minutes. In houses where there was a well-built and well-installed chimney stove, the eyes did not water at all. It was thus felt that if the same person entered a house and recorded the time before their eyes watered a comparative assessment of hydrocarbon and soot concentrations in the air could be obtained. These are related both to comfort and health of the user as the hydrocarbons and carbon monoxide often associated are hazardous to health.
A trial run was carried out on ten houses carrying out eye watering tests and measuring CO emmissions.
Forty four houses were then chosen at random in three different villages in the Kathmandu valley. Of this sample, 8 households had chulos, 8 had agenus and 28 had chimney stoves. Of the chimney stoves, 11 had been properly installed and well maintained, 9 had been well maintained but the chimney had not been well installed and 8 were poorly maintained, with both the chimney and the insert pieces having been badly installed.
The results clearly showed the advantages a well installed stove had in reducing CO levels, although badly installed chimney stoves appeared to be as bad for health as either avenue or Ecu Lou .
The eye watering tests also showed significant improvements in soot and hydrocarbon concentrations. 10 of the 11 well installed chimney stoves and 5 of the 9 moderately well installed chimney stoves did not make the eyes water within 15 minutes. In the majority of households that had either a traditional stove or a poorly installed insert stove, the eyes watered within 5 minutes.
These preliminary results indicate that the introduction of properly installed stoves could play a major role in reducing the incidence of eye and lung disease in Nepal and in avoiding inhalation of toxic levels of CO. There is a very strong case for more stringent monitoring of stove installation and a public education campaign to provide users with sufficient knowledge to correct or report poorly installed stoves.
Review of booklet "Stoves to Save Forests" by W. Minute of The Bellerive Foundation of Geneva - January 1985, 41 pages of dual text English and French, with illustrations.
This booklet is intended for Third World stove designers and gives a brief description of six metal stoves and three clay/metal stoves for domestic use and one clay/metal community stove. Drawings of each stove show the main dimensions along with the results of modified "Boiling Water Tests" using wood fuel.
Some of the stoves are Micuta's developments of existing African Jiko patterns, others are adaptations of traditional European stoves. The fuel efficiencies given vary from 35-47% for metal stoves and 30-46% for clay/metal stoves tested in European winter conditions, outdoors and under cover. Some of the metal stoves are portable, six have chimneys (no details of size or construction). The stoves are stronger and better made than stoves in general use in Africa and Asia and will no doubt be more expensive as well as more durable. All have wire basket grates. Most of the metal stoves are double walled, some insulated but the Hunza (two pot, chimney, metal stove) is single walled as it is intended for areas with some cold conditions requiring space heating. Despite this, the fuel efficiency for a Boiling Water Test is given as 47% and SFC as 0.186.
Micuta believes that only well made stoves, mainly of metal and designed to suit particular metal pots (with lids) can give the fuel saving needed for the campaign against de-forestation and starvation to succeed. He also suggests that in disaster situations large quantities of metal stoves may need to be imported from industrialized countries which produce the sheet metal etc.
Unfortunately his booklet does not provide a comparison with traditional stoves or stoves such as the Improved Kenya Jiko tested under the same conditions. Nor does it give cost figures and so their possible impact on national fuel statistics and economics cannot be estimated, even assuming that the less privileged urban householders were able and willing to buy them. The exception to this is the community stove for which he quotes savings of up to 90% of wood used.
Nevertheless, he gives some new designs and ideas for what may be the next generation of improved metal stoves for the rapidly expanding urban Third World. It would be interesting to hear if there are similar trends in Latin American countries with higher per capita incomes.
By Anne Alexander, FAO/FINNIDA/Report of Senegal (PRECOBA) (May '83, 45pp. French)
This is a detailed description and analysis of the work done by the project since 1982. It concludes that the publicising and promotion of the 'BAN AK SUUF' (BAS) stove was effective in the rural areas but did not result in any 21 significant stove construction after the initial training courses and construction in the houses of the trainees. Proposals are made for a new method of "diffusion". The project complements the Senegal PRECOBA re-afforestation project.
The system of stove construction by village masons was earlier found to be ineffective because of the high price for the rather complicated stove (Fig. 1.) A simplified design was then developed (Fig. 2) but this has also not achieved widespread adoption. This project was based on training rural instructors who show village women how to make their own stoves. The main reason why it did not continue to spread is that mud stove making is hard work and there is no incentive for women to make stoves outside their own homes.
The next plan is to train two women from each village in how to make the BAS and then pay them for each stove they make. It will require more involvement from the Women's Association and the village chief as well as political support. The BAS is considered to be a good design but to have too short a life due to cracking and so needs development.
It is hoped that mud stove construction in rural areas will then "take off" and begin to ease the fire wood problem which is acute in these areas of Senegal.