The gasification technology is new in Nepal. In spite of the technology being promising, the extent of work that has been carried out in this field was limited to laboratory experiment at Research Center for Applied Science and Technology (RECAST) in early 1990s. The Center for Energy Studies, Institute of Engineering (CES, IOE) and many other institutions, at present, have been working in the field of gasifier stoves for both rural and commercial purposes. This paper is concerned with the development of a new class of single pan high efficiency, low emission stoves, named gasifier stoves that promise constant power that can be controlled using any solid biomass fuel in the form of small wood chips or pellets. These stoves use battery-running fan-based air supply for gasification (primary air) and combustion (secondary air). The study mainly deals with the design, fabrication and analysis of efficiency and emission of the stove. Its efficiency depends mainly on the following parameters i) geometric condition of the stove, ii) material used in the stove, iii) fuel or pellets used, iv) the proper ratio of air mixture, v)flow of air and so on. With these parameters, the gasifier stove model was designed by using SolidWorks software. Design with the correct secondary air flow ensures combustion that allows high combustion temperatures accompanying high water boiling efficiencies (up to 50 % 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 or coconut shell pieces ensures operational duration of about an hour or more. The selection of the suitable materials is carried out after studying different parameters. Finally the model, so developed after designing and material selection, is fabricated. After the fabrication, the different tests like smoke emission test and thermal efficiency test are carried out to analyze the emission and thermal efficiency of the gasifier stove. Finally, an economic feasibility study of the gasifier stove is conducted and compared with the economic aspects of existing cooking stove of Nepal.
