Thermal performance of three improved biomass-fired cookstoves using fuel wood, wood pellets and coconut shell

India produces 500 million metric tones of renewable agricultural biomass every year, primarily used as a cooking fuel. Inefficient combustion of biomass is one of the major hindrances for the effective utilization of this vast reserve of energy. Inefficient combustion may occur due to several factors such as lack of proper air circulation, improper packing of fuel and excess moisture content in the fuel. This paper describes the performance evaluation of three improved stoves; natural draft TLUD stove and forced draft Purti and Mpurti stove using three kinds of biomass fuel as wood chips, wood pellets and coconut shell. It was found that the thermal efficiency of the natural draft TLUD stove was 26–27%, electric fan operated Purti stove was 44–45%, and solar fan operated Mpurti stove was 46–48%. This performance was assessed by the standard laboratory-based water boiling test method (WBT) to get thermal efficiency, burning rate, boiling point, specific fuel consumption and firepower. The economic analysis study was carried out to get an idea about the approximate cost that would be incurred per month on the fuel. All these desirable parameters are maximized for the efficient combustion of fuel. The gaseous components like CO and CO2 obtained over the fuel bed are analyzed using gas chromatography. Particulate matter (PM2.5) was measured by the fine particulate sampler. PM2.5 concentration for traditional cookstoves was much higher than studied forced draft Mpurti (510 ± 45 μg/m3) and Purti stove (677 ± 40 μg/m3). The reduction in the indoor concentration of PM2.5 for Mpurti is about 60–63% as compared to traditional stove. Mean CO emissions on a volumetric basis during the cold start and hot start phase were lowest for Mpurti forced draft stove (2.41%). The study reveals that clean cooking can be achieved using the forced draft Mpurti stove.