A Numerical and Experimental Performance Assessments of an Improved Natural Draft Biomass Cook Stove

This article analyses the performance of an efficiently designed biomass cook stove using standard performance parameters. The investigation was first conducted using mathematical modeling developed in the ANSYS Fluent software. The results of primary air and the temperature profiles inside the combustion chamber were found through simulation. It revealed that the flue gas left the combustion chamber with an average velocity of 1.7 m/s. The average pot bottom and fuel bed temperatures were 650 K and 1100 K, respectively. A copper coil was wrapped around the combustion chamber wall to recover its waste heat. The recovered waste heat was utilized to warm the water flowing through the copper coil. The heated water could be used for other domestic applications. The fabricated design of the improved stove was experimented with water boiling test. The maximum thermal efficiency achieved was 42% with a firepower of 8.25 kW, after incorporating the waste heat recovery system, corresponding to 7.5 L test. The overall efficiency, which is the product of the modified combustion efficiency and the maximum thermal efficiency, was found to be 41.50%. The performance was found to be significantly better than that of a commercial biomass cook stove. The developed model was also evaluated for indoor CO, CO2 and PM emissions. The highest levels of CO2 and CO were 940 ppm and 23 ppm. The average amount of PM1, PM2.5 and PM10 found out to be 18 mu g/m3, 20 mu g/m3 and 35 mu g/m3 respectively.