Performance optimization of natural updraft gasifier stoves: Impact of air hole configuration and biomass fuel characteristics on combustion efficiency

Abstract

This study investigates the development and performance of natural updraft gasifier stoves to enhance thermal efficiency, reduce emissions, and improve durability. The stoves were designed with optimized air hole configurations (14–18 holes, 10–20 mm diameter) and constructed using advanced materials, including fire clay bricks and fiber cement, to minimize heat loss and improve structural integrity. Experimental results demonstrated that the gasifier stoves achieved thermal efficiencies of up to 39 %, significantly outperforming the Super stove (32.7 %) and Zedtee stove (30.0 %). Heat loss for gasifier stoves using briquette charcoal was as low as 930 kJ, 4.3 times lower than that of the Super stove and 1.84 times lower than that of the Zedtee stove. Briquette charcoal provided the highest thermal efficiency, while eucalyptus chips achieved the highest combustion efficiency (98 %) despite their greater volatile matter content (59.36 %) and associated emissions. The gasifier stoves exhibited superior durability, with compressive strength (16.25 kN) exceeding that of conventional stoves (6.0 kN) by 2.7 times. These improvements reduced reliance on costly fuels, decreased biomass consumption, and mitigated emissions, achieving a CO/CO₂ ratio as low as 0.22 with LC fuel. Additionally, adopting the developed stove could reduce carbon dioxide emissions by approximately 380–760 kg CO₂ per household annually. Overall, the natural updraft gasifier stove offers an innovative and practical solution for advancing clean cooking technologies, addressing critical challenges in energy efficiency, environmental sustainability, and public health.