Improved Biomass Cook Stove with a Movable Combustion Chamber that Incorporates Top-lit Up Draft and Rocket Principles for Continuous Operation

Abstract

Traditional open fire methods are used by lots of people in developing countries for cooking and heating. These cooking methods are inefficient in burning fuel. In Sierra Leone, majority of the population, especially those living in rural communities, prepare their food using three-stone fire stove, which is inefficient in terms of fuel use leading to more trees being cut down which increases deforestation. A stove that uses less fuel and takes less time to perform heating and cooking tasks can help solve these issues. Thus, the essence of this study, which is to design and produce an improved solid biomass cook stove that can transfer heat more efficiently thereby using less fuel. Mild steel was used to fabricate the entire stove, which is widely available and cheaper. The parts were joined through Arc welding, while four roller bearings provided movement of the combustion chamber for reloading of fuel. Performance of the stove was tested using Water Boiling Test. Thermal efficiency results for the rocket, natural draft and forced draft are 39.55%, 48.68% and 52.48% respectively. Burning rates for forced draft operation was 6.76g/s, while those for rocket and natural are 2.97g/s, 4.11g/s respectively. Specific fuel consumption for the three tests were 0.62 Kgwood/Kgwater, 0.72 Kgwood/Kgwater and 0.77 Kgwood/Kgwater. Time taken to boil water was lowest for the forced draft (6 minutes), which is due to the faster rate of air supplied to the fuel, but it consumed more fuel than the other two methods. These results show that an improved cookstove that is carefully designed is more efficient than traditional stoves, as it facilitates enhanced mixing of combustible gases and oxygen, promoting more efficient burning of fuel and ultimately lowering emissions, thus, better thermal efficiency and reduced fuel consumed will reflect favourably on the environment as less trees will be cut down.