Experimental investigation on thermal performance of three natural draft biomass cookstoves

Abstract

Testing the performance of biomass cookstoves is an important task in front of cookstove researchers. Different cookstove testing protocols are being used across the world for laboratory testing of the cookstoves. Most of the protocols recommend testing the stove at a fixed input power (kW) which is the product of fuel burning rate (kg/s) and calorific value (kJ/kg) of the biomass fuel. In actual field, the operator may operate the cookstove at any suitable input power. This causes difference in laboratory and field performance of the cookstove. Thus, single value of efficiency is not sufficient to describe the performance of a particular cookstove. To simulate actual cooking process through laboratory experiments, it is proposed to generate input power versus thermal efficiency characteristics of the cookstove. The present work involves detailed laboratory experiments on three natural draft biomass cookstoves viz. three stone fire, Panval rocket stove and Berkeley-Darfur stove. The experiments were performed on each cookstove according to modified Bureau of Indian Standards (BIS) Protocol. Each stove was operated at four different fuel-burning rates. Each test was repeated four times and uncertainty analysis was carried out using student’s t test. Input power versus thermal efficiency characteristics were plotted for the three cookstoves. These characteristics help the users to compare the performance of the cookstoves at a given fuel-burning rate.