A self-aspirated two-layer porous radiant burner for high-efficiency biogas cookstoves: Experimental performance and emission analysis

The design, development, and validation of a self-aspirated two-layer porous radiant burner (PRB) for high-efficiency biogas cookstoves meant for off-grid and resource-constrained households are presented in this study. To improve flame stability, encourage air-fuel mixing, and facilitate passive jet-ejector entrainment without the need for external blowers, the burner combines a silicon carbide (SiC) combustion zone with a cast-iron preheating zone. Thermal efficiencies of 51–59% were found through experimental evaluation using water-boiling and emission tests. This performance was close to forced-air PRB performance (53–61%) and exceeded that of conventional biogas burners (46–54%). Emissions of nitrogen oxides (NOₓ) and carbon monoxide (CO) decreased by 29.6% and 79.4%, respectively, indicating cleaner and more thorough combustion. The system's performance parity was confirmed by comparative benchmarking with current porous burner technologies; it achieved 97% efficiency equivalency to forced-air PRBs while removing the need for auxiliary power. Environmental analysis showed an annual reduction of about 12 kg CO₂-eq emissions per household, while economic analysis showed a payback period of about 11 months due to biogas savings of about 9%. Thus, the self-aspired PRB offers a technically sound, financially viable, and ecologically advantageous solution for the sustainable use of biogas. These results transform the design from a proof-of-concept into a verified, ready-to-use candidate for implementation in clean cooking initiatives in Ethiopia and other developing nations.