Impact Assessment and Design Modification of Mirt Stove to Mitigate Carbon Emission; in the Case of Jimma Zone

Abstract

The combustion process in traditional cooking stove is non-ideal and favors incomplete combustion. Incomplete and inefficient combustion produces significant quantities of fine and ultra-fine particles which have more global warming potential than Carbon dioxide. CO2 is among the GHGs which contributes large portion to the ever increasing global warming, it is emitted from sources such as using biomass as fire wood. About 2.6 billion people rely on traditional biomass for home cooking and heating, hence improving the efficiency of household cook stoves can provide significant reduction in GHG emission. Mirt stove is one of improved cook stove which is currently used for Injera baking and heating needs in Ethiopia. The aim of this study is to pave the way for the development of efficient and reliable improved mirt stove which can greatly mitigate the emission of carbon by changing the current design and by providing information on the current distribution and usage of stove. In this work experimental analysis as well as field survey is undertaken to assess the impact of improved cook stove (mirt midija) and it has been found that total of 10,816 tons of CO2 is saved annually and in terms of pure carbon the saving will be approximated to be 2950 tons of carbon is saved annually. Within this study Solid Works 2014 is used to model various geometries of mirt stove and a computational fluid dynamics (CFD) analysis has also been carried out for different newly designed geometries of stove to analyze the heat flow behavior over the stove body during the cooking period using CFD fluent 16 on Ansys. After conducting the experiment on the conventional mirt stove the results for specific fuel consumption is found to be 220g/kg in average. Analytically using surface temperature measured and by considering each mode of heat transfer thermal efficiency is calculated and found to be 25%. Then using CFD analysis done on the same conventional mirt stove it has been found that the thermal efficiency is 34%. Finally for the newly designed stove with improved geometrical model, the CFD analysis is being carried out and a significant improvement on performance is obtained which is estimated to be 48.3% of thermal efficiency.