Moshi Inje Stove
There have been an estimated 12,000 stove projects attempted worldwide, however the Maasai have not seen widespread adoption of improved stoves. Why do so many still practice unsafe cooking in rural Tanzania? The most successful stove projects are those that have been designed locally and for a specific context. The Moshi Inje stove is evidence that this approach can drive innovation and appropriate design.
The Problem
The Maasai cook indoors over an open flame without any ventilation, creating indoor air pollution in the form of smoke and particulate matter. This practice causes blindness, and has resulted in lower respiratory infections being the second highest cause of death in Tanzania - with women and children most at risk.
Before Tanzania
Heat & Efficiency
In order to further explore the application of thermal transfer methods in relation to an improved stove system I conducted testing across multiple stove prototypes. I specifically tested the effects of height, air supply, and insulation. I applied my findings to my exploration and concepts moving forward.
Design Development
Design development sketches with concept refinement labelled (C1, C2, C3, C4)
Concept 1
My first concept (C1) was centered around the idea of converting thermal energy to mechanical energy through the use of a Stirling engine. While this would require little changes to be made to the home and cooking practice, it was ultimately too complex of an idea.
Concept 2
My second concept (C2) was inspired by variations on rocket stoves I had researched. This was the first concept looking to exhaust smoke underground. I learned that there needed to be more air supply for the fire, and that this configuration causes no consistent direction of smoke.
Concept 3
This concept (C3) was the first merging of ideas from the rocket stove and rocket stove mass heater. The pressure within the stove resulted in the lid popping off and the fire burning incorrectly. while the smoke often would exit at one side at a time, I could not keep that exit from alternating.
Concept 4
After extensive research to better understand the airflow used by the rocket stove mass heater - reconfiguring elements, adding a chimney, and adding space to release pressure made this model work (C4). This what was presented in Tanzania, and is the first improved stove to exhaust underground.
In Tanzania
Context
I was able to cook with a Maasai family while in Tanzania. This allowed me to ask questions and form a better understanding of the issue.
Market
Women told us they could not seal the space around stoves with chimneys causing leaks. We also saw that the flame was not well contained.
Manufacture
We visited manufacturing facilities both locally in Longido and in the nearby Arusha. We also were able to see locally available materials.
The Boma
Maasai homes are called bomas. They are mud and manure huts with grass roofing and stick frames that extend underground at select points. The roofing of homes cannot be sealed around chimneys, preventing the adoption of existing stoves.
Presenting & Feedback
I presented working model to Maasai women - many who currently install improved stoves. They were excited and believed my stove concept is feasible, encouraging me to return with my final design. They also provided insights that I was able to apply to the design moving forward.
After Tanzania
Ergonomic Testing
I built a replica of my working model for evaluation and improvement of the user experience. I tested heights above the ground for the cook surface. I also did further research on material limitations.
Form Development
I explored different overall forms using the necessary materials and proportions. I referenced products and manufacture techniques that we saw while in Tanzania for inspiration. Limiting sharp edges was also important.
Model Fabrication
I used solidworks to construct a scale model of my final design. I then used that model to make engineering drawings of individual parts to order from a machine shop. I also used the model when working with a welder.
Final Design - The Moshi Inje Stove
The Solution
The Moshi Inje stove creates safe cooking environments with an improved stove system that directs smoke out of the home under the wall rather than through the roof. The Moshi Inje stove is designed for the context of the Maasai home and is the first improved stove to exhaust underground. The stove does not require changes to be made to Maasai huts, can be installed into existing homes, and safely contains the fire and its heat.
Innovation - Airflow
The Moshi Inje stove uses airflow and combustion methods from the rocket stove and rocket stove mass heater to be the first improved stove to exhaust underground. The materials and configuration of the elements of the stove directs the air through the system in one direction and out of the chimney located outside the home.
Details
Lid
The stove lid is put in place when the user is not cooking. It sits between risers that act to relieve pressure in the stove.
Removable Top
The top of the stove body is removable for easy ash removal. It must be lifted straight upward to be removed.
Fuel Insert
The fuel insert allows for the feeding of fuel into the burn chamber. It also supplies the fire with an air supply.
Use Cycle
Stove Price Comparison
The overall cost of the Moshi Inje stove if it were to be paired with exhaust and a brick chimney is $68.14 CAD. This costs less than the existing stove on the market. This means that under the same business model of NGO subsidization that the existing competitor stove uses the Moshi Inje could be made affordable and competitive.
Materials and Manufacturing
Thesis Project Model
The Moshi Inje stove has been recognized for awards and honours including: Global Grad Show 2020 participant, ACIDO 2020 Rocket Show Winner & sponsored Designforce “Market Ready Award”, Enactus Canada 2020 National Exposition “Scotiabank Climate Change Best Product Idea Award” winner.
What’s Next?
This project is a feasible non-profit pursuit, with a beneficiary size in the tens of millions. There are many reasons for donors to support the Moshi Inje stove: it saves lives while reducing deforestation and carbon emissions. My intention for this project is to continue working toward a final design that minimizes cost while maximizing efficiency. I also aim to get the stove carbon accredited, meaning credits could be provided in exchange for donations. The value of the carbon accreditation of each stove would more than cover the cost of production and installation, meaning that its accreditation would be enough to sustain the project.
