edit this page High altitude smokeless metal stove by Kanchan Rai, A. Zahnd and J.K.Cannell
A Jumla-designed ‘smokeless’ metal stove, manufactured and distributed from 1995, is used by some 2783 families in the villages in Jumla, Mugu and Jumla, in the Karnali zone. Now a stove project, researching secondary combustion, has been introduced at Kathmandu University (KU), based on experience gained from the Jumladesign stove.
[top] [end]Data on firewood (daura) use Firewood accounts for 80% of energy consumption in Nepal, with 90%–100% dependence on firewood in rural mountain areas. According to a survey carried out in 1999 in the remote Jumla VDC of Patrasi and Gothichauer, mountain communities use up to 3000 kg per person (18000 kg per family) of firewood per year, comprising 32% for cooking and 56% for heating, compared with 40% for cooking and 36% for heating in lower hill areas. The remainder is used for lighting, boiling water and agro-processing activities. In Jumla, every home in the remote and high altitude villages uses firewood in open fireplaces for cooking, heating and lighting. In winter, families consume 30 kg– 50kg of firewood per day, using most of the firewood for space heating and cooking.
[top] [end]Rural development data Kathmandu University’s Research Development and Consultancy (KURDC) Unit, sponsored by the ISIS Foundation of Bermuda, has developed a rural energy service development programme for Jumla people. During 2003–2004 a detailed survey of household wealth in the two villages of Chauganphaya (63 houses) and Kholsi (56 houses) measured:
- 95% of the houses are build with stone/mud, 5% with stone/dry masonry
- 94% of households use an open fire and an odhan (one-pot tripod) for cooking, 3% use an open fire with stone supports, and 3% use a non- Jumla designed enclosed stove.
- For heating, 97% use open fire, 1 household uses a non-Jumla designed enclosed stove.
- For lighting: 97% use jharro (a resin soaked pine wood stick from the local available pine tree called salla. One household uses a small Chinese solar PV home system.
[top] [end]Health and environment Women and children are most likely to suffer from the enormous indoor smoke pollution problem, causing respiratory diseases and other serious ailments. Nepal is one of the very few countries in the world with a lower female life expectancy rate than men. The constant deforestation means that people, mainly women and children, spend up to seven hours every second day gathering fuel wood.
[top] [end]High altitude smokeless metal stoves [top] [end]Jumla Design Stove (original design)  Figure 1: Jumla family with no light and with no cooking stove (photo: Kanchan Rai) |
Mr. Alex Zahnd worked for 5 years with the United Mission to Nepal as the Jumla Rural Development Project Director where he developed the Jumla Design stove. Properly used, the stove consumes forty percent less firewood than a traditional open fireplace cooking fire, and also produces nine litres of hot water in a side water vessel. Currently, the stove is installed with a fifty percent (NRp 2500) subsidy to farmers in Jumla; the remainder is raised through project donors. The stoves are manufactured in Nepalgunj, and up to June 2005 a total of 2783 Jumla Design Smokeless Stoves have been installed in the Karnali zone.
 Figure 2: Jumla family with a ‘Jumla Design’ stove (photo: Kanchan Rai) |
This stove is especially designed for use in high altitude areas. It has a flue and three pot holes, enabling an entire traditional meal Dal Bhat (rice, lentil and a vegetable dish) to be cooked at the same time. The attached water vessel provides continuously hot water. A Roti Grilling Device included, allowing roti to be baked in the traditional way directly on the embers. The stove has a mud-filled double bottom for insulation. Air draughts are regulated through an adjustable valve in the main door, and a damper in the flue pipe. Walls are 1.5mm steel, and the upper cooking surface is 4 mm, with 4 mm reinforcing rings. These stoves are portable, and have ‘worn’ well in daily use.
 Figure 3a: Improved stove |
In 2001–2002, two students of KU Mechanical Engineering Department engaged in a Smokeless Metal Stove project to develop a stove, with secondary combustion, that is at least twice as efficient than the ‘Jumla design’ stove. With the sponsorship of SINTEF, Norway, a new prototype KU-2 has been designed and tested.
 Figure 3b: Improved stove schematic |
In the KU-2 stove, firewood is loaded through the main door into the primary combustion chamber. The floor has a grate for air passage into the primary combustion zone. The tray for ash serves as an air passage for both primary and secondary chambers. Separate vents for each air passage control the airflows. There is a water tank made of stainless steel, holding eight litres of drinkable water and a ‘Roti Grill’. In the secondary combustion chamber, hot air from the secondary air passage is mixed with unburned flue gases from the primary combustion chamber to promote further combustion of flue gases, reduce energy losses and increase the efficiency of the stove. After combustion, the cleaner exhaust gases escape through the chimney, which has an adjustable damper to control the draught.
 Figure 3c: Secondary combustion chamber details |
The primary air flowing below the floor is preheated, and the secondary air supply beneath the primary zone floor and up the back of the primary chamber enters the secondary combustion chamber through two layers of nozzles, well preheated. Both secondary and primary chambers are insulated using mud. A baffle plate below the chimney induces better circulation of hot flue gases, making maximum use of convective heat transfer. Air flows are controlled by a primary air sliding vent, two secondary sliding air vents and a damper in the exhaust pipe.
 Table 1: Results |
The secondary combustion stove is still in the design, research and testing phase, though already it has been shown that increased available energy for cooking and heating can be achieved with the same energy input.
Further changes are planned to: the chimney position; secondary air passages; airtight seals; improved energy loss measures; and a glass door (because users insist on keeping the door open so as to see the flames).
Already this stove demonstrates the potential of improved domestic metal stoves for use at high altitudes. Continued design, research and development will allow us to build on our understanding of the processes involved, step by step, until we have developed a truly effective product.
1) Alex Zahnd: Murdoch University (Western Australia) thesis for MSc in Renewable Energy, 2004
2) Kanchan Rai, A. Zahnd and J.K.Cannell, Kathmandu University, Dhulikhel, Nepal
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[top] [end]Contents: Boiling Point 51 - Sharing information and communicating knowledge  . |
Theme Editorial - The Gift of Knowledge - The Upesi Rural Stoves Project - HEDON-The Household Energy Network - Locally-made solar panels for small appliances - Sharing knowledge and spreading information using the Internet - Promoting Solar Cookers Through The Solar Cookers International - Improved Cookstove Technology For Rural Livelihoods For Women - Improved Cookstove Dissemination - HERA Household Energy Programme? - Household energies to improve the quality of life of rural communities - Financing watermill upgrades - Who Benefits From Solar Home Systems In India - The Human And Livelihoods Cost Of Fuel-switching In Addis Ababa - Consensus Reached By Participants At The International Workshop - Monitoring The Charcoal Production Of An Area Under A Sustainable Licensing System - Whats Happening In Household Energy BP51 - Energy News From Practical Action BP51
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