Development of Cookstove Emissions and Performance Testing Suite with Time-resolved Particulate Matter Analysis and Excess Air Estimation

Abstract

Biomass combustion results in 4.3 million premature deaths annually due to indoor air pollution, and contributes significantly to global greenhouse gas emissions and deforestation. The majority of biomass combustion for cooking and heating is done with rudimentary stoves which are inefficient and produce harmful emissions. Improved cookstoves offer a cleaner and more efficient alternative. The design and testing of improved cookstoves requires a sophisticated testing suite to fully characterize stove performance. In this thesis, the design and development of a cookstove emissions and performance testing suite are detailed, with the novel additions of time-resolved particulate matter (PM) analysis and excess air estimation. Time-resolved cookstove emissions monitoring of particulate matter less than 2.5 µm in diameter (PM2.5) are made using a Tapered Element Oscillating Microbalance (TEOM) system. Significant modification and calibration of the TEOM system is presented to bring it into agreement with the standard gravimetric filter method. The real-time measurement system is able to correlate operator actions/operating conditions, specifically during refueling and lighting phases, with transient high PM2.5 events in a wood side-fed natural draft stove. I develop a protocol for estimating the amount of excess air in a cookstove and use it to analyze the amount of excess air present in a wood side-fed natural draft stove with and without a feed door. The cookstove used is found to have a significant amount of excess air present, though the addition of a feed door reduces this. Experimental uncertainties of cookstove performance and emissions testing suite are calculated for individual components as well as global comparison metrics.