|GATE - 4/92 - Networking: Lessons and Hopes (GTZ GATE, 1992, 56 p.)|
The Macadamia Nut and Its Problems
A crafts promotion project in Ruanda urgently needs ideas on how
to produce a small lowprice cracker for Macadamia nuts. Large quantities of
Macadamia nuts are processed, because the harvest has to be "cracked" locally by
the farmers (max. 5 kg per day).
Anyone who has any experience with these round, smooth and very hard nuts and who has some ideas to offer should contact the project in Rwanda direct.
Address: Centre des Metiers Butare ("CMB"), Mr. Rinke, B.P. 335, Butare, Rwanda.
GATE thanks you and appreciates your help.
How to Monitor Awareness Raising
How to monitor awareness raising? This question had to be answered by the Monitoring Section of the Fuel-Efficient-Cooking-Technology Project in Peshawar in Pakistan. This Project is implementing various programmes in the field of energy and environment conservation in the household sector. One of them is the so-called Energy-Education programme, a programme to raise awareness among villagers in biomass resource management and use.
The programme is co-funded by the World Bank and was started several years ago. The working emphasis in the organization is:
- educational material development;
- information courses for villagers;
- exhibitions and public gathering.
The messages of materials and courses are:
- use of fuel-saving devices for cooking, baking, heating;
- design or supply of fuelsaving devices;
- methods for sustaining supply of biomass;
- small scale possibilities for fuelplantations;
- general context of energy management and environment.
In 1991 the monitoring section of the project was requested to evaluate the impact of those measures. The key-questions were: to which extent could awareness be raised, and how was information spread to various groups in a village.
In order to conduct a baseline survey, a random sample was drawn in six villages of two districts, where there had been no activities before. The baseline survey consisted of a set of various open questions about the energy and environment problem.
After finishing the baseline survey the project started with energy education activities in the villages. The evaluation was started soon after completion of exhibitions and courses. The evaluation included all the questions from the baseline survey plus questions about the acceptance of following devices, practices or materials recommended in courses and exhibitions:
- Saplings distributed for each participant for courtyard
- Promotion materials about proper fuel handling and devices.
- Improved metal stoves (Multipotstove), introduced and sold in local shops.
- Use of project-established fuelsaving bakeries;
- Self-construction of an improved traditional clay stove;
- Proper handling of fuel (storage, cutting, fire management, using pots with lid).
The major group classifications were participants of project organized courses or public gathering and non-participants. To control the impact of the baseline survey on the level of awareness, the sample included also a small control group, which was not part of the baseline survey. Even so, the size of the sample turned out to be too small, because of time and money, still, the results picture a fair trend on how the awareness was increased and how information spread throughout the village.
· The questions about the fuel management and conservation methods showed impressive results. In one district the number of people, which could not name any practice of saving fuel, dropped from 60 to 24 percentage.
· The metal-stove was also mentioned by 50% of the total sample as a known fuel-saving measure. This is also reflected in the fact, that 54 percent of participants and 41% of non-participants had bought a stove as a result of the energy education activities.
· The self-construction of an improved mudstove was rarely named as a fuel-saving measure, even so 60 percent of the participants knew about it and 15 percent had constructed an improved mudstove themselves. Many nonparticipants did not know the improved mudstove, but knew the commercial metalstove which indicates that product promotion for commercial products gained more attention, than the self-made product.
Another indicator measured, was the survival-rate of provided saplings, which showed that 86 percent of the participants had received a sapling and that 70 percent of those were still alive after a period of three month.
One of the major conclusions was, that the 20 - 30 percent of the households in each village reached through public gatherings, lectures and courses and information ensured a sufficient spread of information on general topics throughout the village. Device and practice related issues are difficult to spread to groups, which do not personally attend respective meetings.
Copies of the report "First Interim Evaluation of the Energy
Education Activities" can be obtained either through the Integrated Household
Energy Supply Unit (IHV) of GTZ or directly from the Project: FECT P. O. Box
896, Peshawar, Pakistan. D
Jurgen Usinger / Rahmat Jan
The "Sahel" Solar Drier
Drying is one of the techniques most commonly used nowadays for the conservation of foodstuffs. It has been practiced in the Sahel region for generations to preserve a variety of products such as vegetables, meat, fish, cereals, fruit, etc. Traditional drying methods are very simple and basically consist of direct exposure to the sun. However, both the pre-treatment of the product and the drying operations have shortcomings that affect the quality of the dried products.
The products to be dried are often not, or only insufficiently, cleaned beforehand, and are exposed to sources of contamination (dust, insects, etc.) for the whole duration of the drying operation. To overcome these constraints and obtain higher quality products that meet the requirements of the modern urban consumer, the introduction of drying in solar driers protected from the different sources of contamination is a potential solution.
Over recent years the Sahelian countries of West Africa (Burkina Faso, Mali, Mauritania, Niger and Senegal) have gained a lot of experience in attempts to transfer drying technology. Over the last 15 years more than 40 types of driers have been introduced into this region.
No model has yet actually reached the stage of real popularization. The reasons for this are multiple. Problems associated with the cost of purchasing are joined by the frailty of certain equipment (glass or plastic captor surfaces) and lack of flexibility for transportation. These are major obstacles to the rural producer adopting this technology.
The development of the drier shell attempts to solve a number of the above-mentioned aspects. It is a drier of the indirect type, initially made of reprocessed sheets and containing a drying rack.
The Research and Technical Application Group (GRAT) of GATE's cooperation partner CCA in Bamako/Mali has included some modifications to the manufacturing design, leading to the invention of the improved drier shell, with three drying racks. This model is made with an empty 2001 cask cut down, flattened and then shaped.
Flexibility of use, robust form and being transportable are certainly major attributes of the drier shell, but its construction is somewhat delicate for a poorly equipped local craftsman and a handicap to its popularization among small farmers.
The author therefore came up with the idea of a new type of drier, which is equally flexible to use yet workable by rural craftsmen with very limited resources. After discussions with GRAT technicians it was decided to construct a drier.
The new drier has been named SAHEL. It is a metallic ring shaped drier, using natural convection for indirect drying. Its basic design consists of 4 rings, with a cylindrical base, perforated along the side, and with a lid or cover in which a central hole has been made for hot air to escape. The interchangeable racks have a unit surface area of 0.24 m2 and the distance between them is 200 mm. The total height of the drier with 4 racks is 860 mm.
Manufacturing is extremely simper, and consists of the following operations:
- cutting the cask into 200 mm rings
- lateral perforation of the base cylinder
- painting the inner and outer walls of the drier in black
- modeling the interlocking system of the rings
- making support brackets for the racks
- making the racks.
The first drying tests did not carry out any instrumental measurement of the different factors relating to the drying process. Their objective was to collect some empirical figures on the drying process in the new type of drier. These tests were carried out drying fish, tomatoes and mango.
The following observations were made:
- products on the upper racks dry more quickly than those on the
- the products on the lower rack dry more quickly than those on two middle racks
- products on the middle racks have approximately the same drying rate.
The preliminary instrumental measurements in question focused on establishing and monitoring a number of parameters relating to the drying of gumbo or okra in the drier. These measurements were carried out in the month of July, which is a bad season for drying in Bamako.
Indeed, the main features of this rainy season are frequent, covered skies (little direct sunlight) and high atmospheric humidity. Furthermore, the outside temperature is often low in comparison with the yearly average.
The following detailed parameters were measured; temperature and relative atmospheric humidity; air temperature at the inflow and outflow of the drier; wind speed; intensity of insolation; gross weight of the product; weight of the product after pretreatment; product weight when loading and unloading each rack.
This test was made on drying gumbo and was carried out in two stages: the operation of pretreating the gumbo and the determination of different drying parameters.
The type of young okra capsules are broken off and the capsules are cut into slices of about 5 mm thick. Then the amount to be placed on each rack is weighed and the drier is loaded.
Measurements and Results
After loading the driers the above-mentioned parameters were recorded over a 54 h. period. The recording beginning at 12.0 o'clock (midday) on the first day. The relative humidity was measured in the atmosphere air as well as at the outflow (exit) of the drier at 30 minute intervals.
The ambient temperature, the temperature at the exit of the drier, wind speed and intensity of insolation were recorded every 30 minutes. The drier was emptied every evening and the residual weight of the gumbo determined.
The following conclusions can be drawn from the test:
- about 80 % of the initial weight of the gumbo was removed in the form of water;
- after these 54 h, the gumbo was still not dry enough for storage over a relatively long period of time (for this purpose a drying ratio of 1/10 is required, i.e. a final weight of about 365 g.);
- the average drying rate (quantity of water evaporated per hour) over the period in question is approximately 53.80 g/h.;
- during the daytime an average rate of about 89.4 g/h. is achieved compared to approximately 9 g/h. at night.
The differences between the rates of dehydration at the different rack levels could be quantified in detail, partly confirming the empirical observations mentioned above.
The following dehydration rates were determined from the bottom rack upwards:
Rack I: 25.00 g/h
Rack II: 17.80 g/h
Rack III: 15.14 g/h
Rack IV: 23.62 g/h.
These preliminary figures confirm the interesting aspects of this type of apparatus, in which grade drying levels can be obtained in a single drier. This phenomenon could, theoretically, be expanded by increasing the number of rings and the number of racks, providing the Sahel drier with a degree of flexibility which would enable it to treat, in one single operation, products requiring different drying conditions.
The measurement programme will continue at the end of the rainy
season and should eventually provide a database on the technical performance of
this new type of drier.