Posted on Engineers Without Borders:
http://www.ewb.org.au/announcements/748/10743
The main source of energy for 94.1% of rural households is firewood, whereas in urban areas, the main sources of energy are firewood, kerosene and some other sources of commercial energy. It is estimated that residential cooking, which accounts for about 65% of the total energy consumption in rural areas, is the single largest energy end-use activity. Reduced traditional sources (firewood) of biomass due to deforestation has forced the shift to dung in many regions, an energy fuel with low energy content, e.g. in the Terai, the primary source is dung. Dung being used as fuel has different characteristics to wood, where the ash and volatile content is larger, carbon content and burning ratio is lower, and the ratio of primary to secondary air needed is different.
Rural Nepalese populace has been cooking using traditional mud stoves for decades. The cultural attachments of the people with these kinds of stoves are so strong that people are not expected to change their stoves in a short term. Thus, dependence on biomass is expected to continue in the near future. The traditional mud stove, though easy to construct, has many design faults which makes it extremely energy inefficient when using alternative biomass sources such as dung, leading to long cooking periods, high wastage of dung, and further negative impacts on people’s health due to high smoke exposure. This compels us to analyze the design problems of traditional mud stoves to increase its efficiency, and allow the use of alternative, more accessible biomass fuel such as dung.
Previously improved mud stoves disseminated by the LFP (Livelihood Forestry Programme) failed, primarily as it did not burn fuel more efficiently as claimed and in appearance the stove resembled the traditional mud stove. Community consultation has shown that people have preference for more modern looking metal stoves. Studies on metal stove designs from India have shown that there has to be a proper and sufficient supply of primary and secondary air for efficient combustion of the fuel and the volatiles generated, while care has to be taken that the ash created by the combustion of the dung does not restrict the flow of primary air. Also, the combustion chamber has to be large enough to accommodate enough fuel to last the cooking period desired.
Taking these into consideration, we have worked on developing a clean dung-burning stove. The stove would incorporate all the characteristics required for the efficient burning of dung as well as incorporate some of the simplified characteristics of a Top-Lit Up Draft (TLUD) gasifier. The design characteristics and innovations of the improved stove include two-layer ceramic insulated walls, a fuel grate for placing the dung and allowing easy flow of primary air beneath the dung, provision of a secondary air inlet, a chimney structure, a baffle plate, etc.
The project contributes to Nepal's efforts at sustainable development by improving the standard of living of rural Nepalese households, improving health, improving the environment, and enhancing social equity.
http://www.ewb.org.au/announcements/748/10743
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Lighting a traditional stove using dung pieces and twigs
Dung Burning Stove for the Southern Belt of Nepal
Sarbagya Tuladhar has been working with Namuna and the Child Welfare Scheme and EWB Australia in designing an improved dung stove for rural poor in Nepal.
Posted by Ian Cunningham to CWS (Child Welfare Scheme), 18th April 2011, 5:11pm
Nepal’s energy crisis is felt across the country and experienced varyingly across the nation. The rural poor, who do not have ready access to commercial energy sources, use traditional cooking stoves and biomass fuels that can be collected or sourced locally. Biomass includes things like wood, dung and agricultural wastes. Access to these fuels is rapidly diminishing with deforestation, rising prices and population pressures. Additionally, traditional fuels and stoves continue to impact the health, economic and social well being of Nepal’s rural poor. The Dung Burning Stove Project of Namuna and Child Welfare Scheme (CWS/UK) with assistance from Engineers Without Borders (EWB) Australia is attempting to address these issues with the design of a more efficient dung burning stove for the Southern Belt of Nepal.The main source of energy for 94.1% of rural households is firewood, whereas in urban areas, the main sources of energy are firewood, kerosene and some other sources of commercial energy. It is estimated that residential cooking, which accounts for about 65% of the total energy consumption in rural areas, is the single largest energy end-use activity. Reduced traditional sources (firewood) of biomass due to deforestation has forced the shift to dung in many regions, an energy fuel with low energy content, e.g. in the Terai, the primary source is dung. Dung being used as fuel has different characteristics to wood, where the ash and volatile content is larger, carbon content and burning ratio is lower, and the ratio of primary to secondary air needed is different.
Rural Nepalese populace has been cooking using traditional mud stoves for decades. The cultural attachments of the people with these kinds of stoves are so strong that people are not expected to change their stoves in a short term. Thus, dependence on biomass is expected to continue in the near future. The traditional mud stove, though easy to construct, has many design faults which makes it extremely energy inefficient when using alternative biomass sources such as dung, leading to long cooking periods, high wastage of dung, and further negative impacts on people’s health due to high smoke exposure. This compels us to analyze the design problems of traditional mud stoves to increase its efficiency, and allow the use of alternative, more accessible biomass fuel such as dung.
Previously improved mud stoves disseminated by the LFP (Livelihood Forestry Programme) failed, primarily as it did not burn fuel more efficiently as claimed and in appearance the stove resembled the traditional mud stove. Community consultation has shown that people have preference for more modern looking metal stoves. Studies on metal stove designs from India have shown that there has to be a proper and sufficient supply of primary and secondary air for efficient combustion of the fuel and the volatiles generated, while care has to be taken that the ash created by the combustion of the dung does not restrict the flow of primary air. Also, the combustion chamber has to be large enough to accommodate enough fuel to last the cooking period desired.
Taking these into consideration, we have worked on developing a clean dung-burning stove. The stove would incorporate all the characteristics required for the efficient burning of dung as well as incorporate some of the simplified characteristics of a Top-Lit Up Draft (TLUD) gasifier. The design characteristics and innovations of the improved stove include two-layer ceramic insulated walls, a fuel grate for placing the dung and allowing easy flow of primary air beneath the dung, provision of a secondary air inlet, a chimney structure, a baffle plate, etc.
The project contributes to Nepal's efforts at sustainable development by improving the standard of living of rural Nepalese households, improving health, improving the environment, and enhancing social equity.
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