The Modified Turbo Stove: The Flamethrower

1. By: Ali Brozek, Erika Union, Will Hitchcock, and Mike Deagen The Modified Turbo Stove: The Flamethrower

2. The Need: • Nearly 3 billion people currently use open fires or unsafe stoves to cook • Respiratory problems caused by these cooking methods are more fatal to children than malaria • 1.6 million people die each year from inhaling smoke from cooking Source: http://www.stovetec.net/us/index.php?option=com_content&view=article&id=133&Itemid=684

3. The Mayon Turbo Stove: • The Mayon Turbo Stove uses rice hulls as fuel • Rice is the number one food crop in the world so rice hulls are an abundant agricultural waste • The stove has the potential to provide an inexpensive and safer way to cook while slowing deforestation by using waste as fuel Source: http://www.reap-canada.com/bio_and_climate_3_3_1.htm

4. Problems with the MTS: • The Turbo Stove burns rice hulls very well but lacks an exhaust system and the gas the fuel releases when it burns is toxic • The stoves are difficult to manufacture • The design is physically unstable Image Source: http://bioenergylists.org/lotrau

5. Group Purpose: • Modify the existing plans for the Mayon turbo stove or last year’s Burninator in order to provide a stove that is: • Safe: can be used in homes without dangers of smoke inhalation • Inexpensive: easy to manufacture • Efficient: runs on rice hulls • Practical: boils water quickly • Easy to use: starts burning quickly and easily!

6. Testing the two existing stoves: Mayon Turbo Stove The Burninator

7. Observations: • Mayon Turbo Stove: • Easy to start the fire, BUT: • Is unstable (falls over easily) • Has no system for safe exhaust removal • Is impractical for cooking • Burninator • More sturdy, shows promise for improvements BUT: • Is very difficult to start the fire • Has no system for safe exhaust removal • Needs a cooking surface • Fuel intake compartments and carburetor are inefficient

9. What did we actually do this quarter??

10. 1. Initial Testing Hamster Bedding Rice Hulls

11. 2. Adjusted Carburetor

12. 3. Used Plasma Cutter to separate the vertical chamber from its legs.

13. 4. Welded the cone to the top of the chamber.

14. 5. Added metal fittings to corners.

15. 6. Detached the vertical chamber

16. 7. Adjusted the Carburetor again

17. 8. Added ramps to focus fuel. Shaping the Ramps The Shaped Ramps

18. TIG Welding the Ramps In The Final Product

19. 9. Put Mud along Cone to ensure airtight PS. Thanks Mud Stove Group!

20. 10. Replaced chamber and adjusted feeder angles.

21. Goal: Increase angle with a bigger opening (1”  2”)

22. 11. Test Again!! • Feed from one side • Lighting from top • Lighting from bottom • Used a fan

23. 12. Make a new stove including our observations! • One feeder • Make carburetor closer to feed to increase airflow • Longer exhaust • Lip at end to control fuel

25. The Flamethrower! Tested: Doesn’t work

26. Schematic of the “Flamethrower” • Simpler manufacturing than the Mayon Turbo Stove • Fuel intake on one side only • Ash is collected on the same side smokestack fuel hopper air intake ash collector

27. Schematic of the “Flamethrower” • Simpler manufacturing than the Mayon Turbo Stove • Fuel intake on one side only • Ash is collected on the same side rice hulls twin pipes perforated aluminum sheet metal

28. How Rice Hull Combustion Works • Initial kindling or fire starter necessary • Rice hulls outgas between 200-450°C (392-842°F)1 • Below 200°C, negligible decomposition • At 200°C, darkish yellow • At 450°C, >90% of volatile matter separates • Proper fuel-to-air mixture sustains the burn 1M.A. Hamad. “Thermal Characteristics of Rice Hulls.” 28 January 1981.

29. Removing Hazardous Smoke • Rice hull ash and smoke contain silica, SiO2 • Same material as sand • Need to prevent inhalation of smoke • Exhaust system to redirect any smoke • The smokestack was effective, and the only smoke came out of the top • Next design needs to ensure good air quality

30. Getting Rid of the Ash • Tap the side of the stove, gravity will cause more fuel to feed in and the ash will fall into the ash collector • For ease of use, the ash collector and fuel feed are facing the same side of the stove

31. Ideal Air Flow • Air flows through the fuel, combines with the outgas, and combusts • Convection draws the hot air upward to the stovepipe, which draws more air through the intake to balance the pressures

32. Actual Observed Air Flow • Air preferentially flows around the rice hull tray • Not enough air gets to the rice hulls to sustain a clean burn • The rice hulls simply smolder and produce a lot of smoke

33. Redesign Considerations • Air will flow in path of least resistance • Maximize amount of useful air to the rice hulls • Block areas where non-useful air can flow • Effective method for removing ash • Ability to CONTROL the fuel and/or air • Air and heat flow through rice hulls is difficult • The thermal resistance R-value for rice hulls is about 3.0 per inch, good for insulation2 2P. A. Olivier. “The Rice Hull House.” 2004.

34. Recap

35. Hot Potato

36. Help Encourage Continuation of Project

37. What does version 3.0 look like? • Complete redesign or modification of the Flamethrower • Focus on utilizing all airflow in the burn system • -Exhaust system and cook-top • -Integrate design with mud stove

38. Questions???