20. IMPROVED CHULHAS.ppt
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The document discusses the importance of improved wood stoves in rural India, highlighting the decline of wood energy and its reliance on traditional stoves with low efficiency and high smoke production. It presents various designs for improved stoves, their components, efficiency ratings, and the necessity for better combustion practices to reduce smoke-related health issues. Additionally, it compares the performance of biomass gas stoves with conventional wood stoves, showcasing their benefits in reducing fuel consumption and emissions.
20. IMPROVED CHULHAS.ppt
- 2. INTRODUCTION Wood is an important energy source in rural India Wood energy is declining in the increasing rate because of rapid depletion of natural forest resources Main uses of wood energy is for cooking
- 3. TRADITIONAL WOOD STOVES Three stones fire Why Popularly adopted? • Feeding and combustion control easy • Any size pot can used • No special skill required • Control of insects Drawbacks • Low efficiency (8-10%) • Smoke formation • Use of fuel wood inefficiently
- 4. NEED FOR IMPROVED WOOD STOVES To prevent smoke and soot production For saving fuel wood Women labour time To reduce lung and eye diseases
- 5. IMPROVED STOVES Less smoke production Less quantity of fuel utilization Efficient heat transfer Less heat losses Efficiency (20-35%)
- 6. STOVE COMPONENTS FIRE BOX • Enclosed space for combustion • High energy release due to complete combustion AIR INLET • Secondary air is introduced in the fire box GRATE • Made up of frame of metal bars • Increased efficiency due to entry of secondary air if grate and air inlet is used
- 7. BAFFLES • Projection in the combustion chamber placed at the exit of combustion chamber DAMPERS • Movable plate in the chimney • Made up of steel plate CHIMNEY • Metal or asbestos pipe • Helps in releasing the smoke and creates draft for complete combustion
- 8. COWL • Metal cap for avoiding the entry of foreign material as well as rain water • Increases the draft TUNNEL • In multi-pot closed chulha
- 9. DESIGN PRINCIPLES FOR EFFICIENT STOVES Insulate the combustion chamber Use an upright chimney with damper Heat energy should be used only for the burning of fuel Maintain a good air velocity through the fuel for complete combustion Minimum quantity of excess of air during combustion Distribute airflow around the fuel surfaces Air should largely flow through the glowing coal/wood
- 10. SINGLE POT TNAU CHULHA Double wall Grate Legs Secondary air openings Inner wall holes Mounds Fire mouth TNAU SINGLE POT CHULHA
- 11. SINGLE POT TNAU CHULHA Double wall Grate Legs Secondary air openings Inner wall holes Mounds Fire mouth TNAU SINGLE POT CHULHA
- 12. TNAU CHULHA Cost : 75/- Efficiency : 24%
- 13. TNAU DOUBLE POT CHIMNEYLESS CHULHA • Double wall • Tunnel • Secondary air inlets • Grate • Legs (6) • Inner wall holes • Mounds TNAU DOUBLE POT CHIMNEYLESS CHULHA
- 14. TNAU DOUBLE POT IMPROVED CHULHA
- 15. TNAU DOUBLE POT CHIMNEYLESS CHULHA Cost : 150/- Efficiency : 26%
- 17. UDAIRAJ CHULHA Material Chimney Fire box Firebox opening Connecting tunnel Cost: 230/- Efficiency : 25.5% Suggestions • Soot removal hole • Provide grate • Optimize air opening
- 19. CPRI DESIGN CHULHA Non-chimney Availability in sizes Portable Cost: 175/- Efficiency : 26% SUGGESTIONS • Adjustable air opening • Provide tray like structure • Side insulation
- 20. EVALUATION OF THERMAL EFFICIENCY WATER BOILING TEST o For determining thermal efficiency of wood stove o Location specific multi-model approach of government for popularization of locally made stoves o Uniform testing code for performance evaluation INSTALLATION OF CHULHA o Site o Chimney o Fuel opening
- 21. VESSEL o Flat bottom or cylindrical shape o Lids o Clean and dried
- 22. CALCULATIONS H1 = w1i(t2-t1) + w2i(t3-t1) H2 = (w1i - w1f)L + (w2i - w2f)L H1+H2 η = ----------- mF x CV mF x CV x η Power Rating = ----------------------- 860 PROCEDURE
- 23. CONTROL COOKING TEST • To assess the performance of the improved stove • Standard cooking task FUEL o A homogeneous mix o Divided into pre-weighed bundles
- 24. FOOD AND WATER o Sufficient o Homogenous COOKING POT (S) o Most appropriate pots o Record the specifications
- 25. CALCULATIONS a. Total weight of food cooked (Wf) b. Weight of char remaining (Dcc)
- 26. c. Equivalent dry wood consumed (fd) d. Specific fuel consumption (SC) e. Total cooking time (Dt)
- 28. TNAU BIOMASS GAS STOVE Principle – updraft gasification Woodchips, agricultural residues, dry leaves, barks Cylindrical – clay and rise husk Iron grate – 50mm
- 29. BIOMASS GAS STOVE WORKING CONDITION
- 30. PREFORMANCE DETAILS OF BIOMASS GAS STOVE Working Principle : Updraft Gasification Feedstock : Wood chips, agricultural residues, such as coconut shell, groundnut shell, arecanut husk etc. Thermal : 24-28 % Flame temp : 600-700 0C Heat output : 4.4 kW Heat release rate : 63 kcal/min Emissions - CO : 500 ppm TSP : 0.10 mg/m3 Sp. fuel consumption : 0.27 kg/h of processed food Saving in fuel : 15-18 % over conventional stove Cost : Rs. 300 Applications : Small scale thermal applications in farms, households, Tea shops, Turmeric boiling, Paddy Parboiling, etc.
- 31. BIOMASS GAS STOVE – CHARACTERISTICS
- 32. BIOMASS GAS STOVE AT USER’S SITE AT OOTY
- 33. COMPARATIVE PERFORMANCE OF WOOD BURNING STOVES Details Conven- tional Single Pot Chulha Double Pot Chulha Biomass Gas Stove Working principle Combustion Combustion Combustion Gasification Thermal , % 10-12 19-24 24-26 24-28 Flame temp, 0C 400-500 400-500 400-500 600-700 Heat output, kW 0.7 1.2 1.8 4.4 Heat rate, kcal/min 10 16 22 63 Emission CO-ppm level TSP- mg/m3 3500 0.69 2000 0.20 1500 0.20 500 0.10 Cost - Rupees 55 75 150 300 Sp. fuel consumptn 0.36 0.30 0.30 0.27 Saving in fuel, % -- 9-11 10-13 15-18 Application Household heating Household heating Household heating Houses, Farms, Tea shops, Turmeric boiling, Paddy Parboiling
- 34. CONCLUSION We can use the improved wood stove designs to reduce the concentration of smoke and indoor air pollution We can save the time and money
- 35. TESTING OF BRIQUETTES IN BIOMASS GAS STOVE ASH CLINKERS