A comparison of emissions and thermal efficiency of three improved liquid fuel stoves

Research has shown that there is a clear link between emissions from inefficient domestic cooking appliances and the prevalence of respiratory infections and cardiovascular diseases. This has prompted the need for the development and dissemination of efficient clean cookstoves for cooking and heating purposes. Although liquid fuels are rated cleaner than traditional solid fuels, their combustion in basic and poorly designed stoves leads to problems of household air pollution and fire hazards. Information on the combustion, pollutant emissions and thermal performance of liquid fuel stoves is still scarce and there is a need to address this gap. This study characterises emissions and thermal performance of three liquid fuel stoves - kerosene stove, an ethanol gel stove and a prototype methanol stove. Kerosene/paraffin stoves are widely used in the low-income settlements in South Africa, while the ethanol gel and methanol stoves are new entrants in the market place. The `hood´ method was employed to collect the flue gases and particulate emissions, and to measure emission factors for the devices. The SeTAR Centre heterogeneous stove testing protocols (HTP) was employed to determine the average CO and PM_2.5 emissions, as well as the CO/CO₂ ratio and thermal efficiency of each device. The methanol prototype stove reported better combustion efficiency compared to the ethanol gel and the kerosene stoves. Although the methanol stove has improved combustion efficiency compared to the other stoves, the fire-power is below the recommended standard and user expectations.