Fabrication and Performance Analysis of a Biomass Cook Stove

improving the thermal as well as emissions performance of biomass cook stoves has been of interest to researchers for a long time. Despite there being a vast literature on the subject, several technical issues remain unresolved with a variety of data and opinions being presented. This project is concerned with the development of a new class of single fan high efficiency, low emission stoves, named biomass gasifier stoves that promise constant power that can be controlled using any solid biomass fuel in the form of pellets. These stoves use battery-run fan based air supply for gasification (primary air) and for combustion (secondary air). Design with the correct secondary air flow ensures near stoichiometric combustion that allows attainment of peak combustion temperatures with accompanying high water boiling efficiencies (up to 35 % for vessels of practical relevance) and very low emissions (of carbon monoxide, particulate matter and oxides of nitrogen). The use of high density agro-residue based pellets ensures operational duration of about an hour or more at power output of 1.5 kW (18 g/min). The principles involved, the optimization aspects of the design are outlined. The dependence of efficiency and emissions on the design parameters are described. The field imperatives that drive the choice of the rechargeable battery source and the fan are brought out. The process development, testing and internal qualification tasks were undertaken at RCOEM Nagpur. This technology was initially developed as a business by BP, India (earlier) and subsequently taken on by FEPL. At this time, over four hundred thousand stoves have been sold in four states in India. The implications of such developments to the domestic cooking scenario of India are briefly brought out.