Efficiency and emissions from improved cook stoves: A study of Kuni Mbili improved stove





Almost all rural and a good number of urban families in Kenya rely solely on wood for their cooking needs. The traditional method of cooking in Kenya and many other third world countries is on a three stone cooking fire. It’s cheap to produce requiring only three suitable stones of same height on which a cooking pot can be balanced over a fire. However this mode of cooking over the years has proven to be highly inefficient, unhealthy and contributes considerably to other environmental risks that threaten the quality of human life.


It is in view of the above challenges that improved cook stoves were conceived and introduced; to help a vast majority of humanity meet their household cooking and heating needs without the risks posed by three stone fires. Improved cook stoves are designed to consume less fuel, save cooking time by increasing thermal efficiency and reduce gaseous and particle emissions that pose serious health risks to users. The purpose of this study project was to evaluate Kuni Mbili, an affordable improved cook stove found locally, to ascertain how well it meets this criterion.


Both stoves were tested under the standard water boiling test protocol (WBT) by performing the cold-start high-power, the hot-start high-power and Simmer tests. These are simplified simulations of the cooking process in a household kitchen. Results were then entered into a WBT data calculation sheet to obtain all the parameters critical in evaluating and discerning the stoves performance.


Analysis of the results obtained indicated a significant difference in emissions, both gaseous and particulate, between an improved cook stove and a traditional three stone fire. Increased thermal efficiencies from improved stoves were also observed by reduction in the amount of fuel used to boil same amount of water. The results also portrayed the potential of improved stoves to reduce the effects of biomass combustion on global warming, an area of great interest lately.


Adoption and sustained use of improved cook stoves will lead to improved livelihoods through improved health, time savings for households and other indirectly derived economic benefits. A sustainable future can also be realized through reduction in mass utilization of biomass hence preservation of forests and associated ecosystems.

Fourth Year Projects-2012-Boniface.pdf84.89 KB