Modeling and numerical simulations of heat transfer performance in clay-metal composite Injera baking pans using COMSOL multiphysics

• The study provides a clay-metal composite Mitad to enhance heat transfer efficiency. • Simulation results demonstrate improved thermal performance, uniform temperature distribution, energy, and time savings. • Maxwell-Eucken modeling outperforms in predicting composite conductivity compared to Series, Parallel, and Rule of Mixtures models. • Adoption challenges persist due to economic constraints, cultural preferences, and limited awareness, emphasizing the need for community outreach and policy support. • Research findings suggest that clean biogas-based cooking systems may have health and sustainability benefits. Traditional Injera baking relies heavily on biomass fuels and low-efficiency clay baking plates (Mitads), leading to significant environmental degradation and respiratory health risks. This study investigates the enhancement of Mitad thermal performance through the development of clay-metal composites using copper (Cu), aluminum (Al), and steel additives at volume fractions of 0% to 30%. Four analytical models, including Series, Parallel, Rule of Mixtures, and Maxwell-Eucken, are evaluated to predict effective thermal conductivity, with results validated through COMSOL Multiphysics simulations and comparison with experimental literature. The results demonstrate that the Maxwell-Eucken model provides the most accurate and physically realistic predictions for these heterogeneous composites, whereas the parallel and rule of mixtures models significantly overestimate thermal gains. Additionally, the study also seeks to investigate the influence of various additive materials by examining thermal efficiency, temperature distribution, and heat retention. Copper additives provide the highest thermal performance due to their superior intrinsic conductivity, followed closely by aluminum, while steel offers a cost-effective alternative with slightly lower but still significant improvements. The optimized composite Mitads reduce heating time by up to 56% and lower fuel consumption by over 50% compared to conventional clay Mitads. These findings highlight clay-metal composites as a technically viable and sustainable solution for improving energy efficiency and indoor air quality in biomass- and biogas-based cooking systems.