Appropriate Technology Stove Research Group
INTRODUCTION: Each of our group members has an interest in helping with the problem of inefficiency and wastefulness of cook stove in developing countries. We chose this topic within our class because we felt that with our research, designing and testing, we could aid working villages or other similar organizations in designing an efficient stove. Our goals, progress and results are below. Enjoy!
In the 10 week course:
-LINK to learnings…
-LINK to achievements..
All new technology, images and designs of prototypes are the intellectual property of: Harrison Bergholz, Stephan Jackson, Ellie Kalman and Tina Sweeney and may not be reproduced or used without written consent.
PROBLEM STATEMENT: While the Mayon Turbo Stove (MTS) uses biowaste as its fuel source, we found the MTS to be unstable, unsafe, required frequent maintenance while cooking and it produced significant amounts of smoke while igniting and extinguishing the fire.
1. Design a more efficient and safer stove that burns agricultural waste products.
2. Find locally appropriate design solutions/models that draw upon the local resources of whatever community this stove model is implemented in
3. Establish a working relationship with Working Villages International and/or San Pablo. http://www.workingvillages.org/main.html
The community of San Pablo is not in need of a new stove design, but rather educational programs on how to better use the current stoves.
New Focus: Working Villages International (WVI)
WVI has tried using the MTS but it has not been widely accepted in the community
A more efficient biomass stove combustion unit and several stove designs that can be modified for various community partners.
DIVERGENT/CONVERGENT THOUGHT PROCESS: Our team originally wanted to improve ventilation for the smoky homes in San Pablo, Guatemala based on feedback from the previous team’s visit to the community. Upon further inspection, the stoves appear to be in working order and the smoke issue was rather a matter if education of stove use. Our team worked on a design matrix to help guide us to our new group focus. After taking into consideration such as cost, ease of use, ease of assembly, health, efficiency and enviornmental impact, we decided to create a new stove that combines the Mayon Turbo Stove with a Rocket Stove.
DESIGNS AND EXPERIMENTS
We began our study of stoves by repairing a Mayon Turbo Stove made by a previous group of students. We then tested the stove using rice hulls as fuel, to learn about the efficiency of the stove and its features that make this stove successful. The test burn was completed on January 21st, 2011. The MTS is a stove created by the group RAEP-Canada ( Link ). It is used in many developing countries and uses rice hulls as its source of fuel. We took interest in this stove as it uses a biowaste product for its fuel and has a unique preheating element. Our progress and results can be found at this link (now with cross section).
After testing the MTS, we went back to our design matrix and focused on making a rocket stove with elements of a MTS. From research, we learned that a rocket stove can have greater heat combustion and we proposed it would be more sturdy and safe than a MTS. Our 1st Prototype, named the Ricey Rocket Stove was built and then tested on Feb 6th, 2011. The results and features of the stove can be found here.
The major problem of the Ricey Rocket Stove seemed to be that the fire was not getting enough oxygen to stay ignited and there were gaps in the stove where vast amount of rice hulls were escaping. We made numerous modifications to it in hopes that we would be able to get the stove to burn a fire. Some of these modifications included welding pieces of steel in gaps where rice hulls fell through, cutting a larger opening in the bottom where rice hulls burn, and adding in cylindrical tubes from the bottom of the stove for increased air flow to the fire. We named this remodeled stove the Happy Doomsday Stove II. It was tested on February 14th, 2011. The results and images for the 2nd prototype can be found at this link. Unfortunately, this prototype also did not burn. We think that the thickness of the steel did not allow for the rice hulls to be heated.
After building and modifying a steel rocket stove, we decided to take all that we have learned thus far and apply it to constructing a new stove! This time, we used a thin sheet metal that is light and easy to work with. We hope that this will allow for the preheating element that we saw in the original MTS. The stove features adjustable chutes that can be put at varying angles to see what angle works best to burn the rice hulls. We also made plates that can choke the entry of rice hulls to allow for more of less to enter the burn chamber. We named this stove the Transformer Stove, it was tested on February 28th, 2011. Images and more information can be found at this link. The stove did not stay lit. After going back and retesting the MTS, we realized that our stove was lacking a inner cone that was an essential component of the MTS.
Revisiting the MTS provided us with a greater insight to what our stove design could be lacking and thus not working. We added a inner cone to the burn chamber in order to concentrate the heat provided by the fire. We also added a burn tray for the rice hulls to rest on as they exit the chute. Before, this area was a flat drop. Now the rice hulls have a sloped steel gradient to again try to concentrate the burn area and heat. This was a feature we also modified from the MTS. Images can be seen here (now with cross section). Test burn took place on March 7th. It was a success! Although there are still modifications and improvements to be made.