Design optimization and experimental validation of a biogas-powered stove for energy efficiency in injera baking in rural Ethiopia.

Abstract

Injera baking is an energy-intensive daily activity in most Ethiopian households, traditionally reliant on firewood or grid electricity. Biogas presents a cleaner, more sustainable alternative, yet its application for injera baking remains limited due to excessive fuel consumption, uneven heat distribution, and inefficient stove designs. This study addresses these challenges by developing and validating a purpose-built biogas-powered injera stove. A novel burner configuration was designed, comprising five concentric feeding loops with a total of 93 carefully sized holes, and incorporating 20 mm fiberglass insulation to minimize heat loss. Unlike earlier general-purpose biogas stoves, this system was specifically engineered to meet the unique thermal and geometric requirements of injera baking. Computational Fluid Dynamics (CFD) simulations were conducted to optimize biogas flow and flame characteristics, revealing a maximum flame temperature of 1954 K with uniform distribution post-deflection by the baking pan. Experimental validation confirmed the simulation results, achieving a flame height of 33 mm and a diameter of 45 mm. The improved stove heated an 18 mm aluminum pan to 140 °C in under 10 min at a biogas consumption rate of 0.9 m³. The system achieved an efficiency of 43.11%, significantly higher than conventional designs as indicated in Table 3. This integrated design-simulation-validation approach demonstrates the technical feasibility of efficient, biogas-based injera baking for rural Ethiopian households.