Design and testing of an automated cookstove fuel feeder for standardized laboratory testing

Abstract

Laboratory testing of cookstoves aims to compare performance of stove designs under controlled and uniform conditions, with fuel feeding being an important parameter. This study explores whether a robotic cookstove feeder can reduce variability between laboratory tests of a cookstove, produce statistically similar firepower and measured emissions rates, and reduce tester interaction time during standard cookstove testing as compared to a trained human operator. A series of modified ISO/FDIS 19867-1 tests were performed by the robotic cookstove feeder designed for this project and compared to equivalent tests performed by two human operators. Testing included four unique configurations, two levels of firepower per configuration, and five replicates per firepower. The results showed that the robot cookstove feeder did not reduce variability, but was as consistent as the results from the human tests. A matched pair t-test at a 90% confidence interval revealed no statistical difference in firepower or PM2.5 emissions rates. However, the human and robot's CO2 emissions rates were very similar, with the robot average lower by 6.2% (SD = 6.4%) and higher by 4.2% (SD = 6.2%) on average for the high and medium testing power respectively. The human and robot's CO emissions rates differed more, with the average percent difference being 9.8% (SD = 25.4%) higher for the robot at high power and 21.7% (SD = 19.5%) higher for the medium power. A comparison of the tester interaction time showed that the robot on average saved the operator some time, although additional data are needed for this metric. Finally, there were mixed feelings about usability from the operators, with one operator reporting that the robot did not reduce the testing burden significantly. The results indicate that the robot is capable of performing repeatable cookstove testing and future iterations of the robot may provide opportunities to increase consistency in testing across cookstoves, operators, and testing facilities.