Design, Simulation, Fabrication and performance evaluation of a Scoria-Insulated, PID-controlled charcoal stove for efficient cooking

Access to clean and efficient cooking technologies remains a significant challenge in sub-Saharan Africa, where traditional charcoal stoves are characterized by low thermal efficiency, high fuel consumption, and elevated emissions. This study presents the design, modeling, fabrication, and performance evaluation of a novel scoria-insulated, PID-controlled charcoal stove aimed at overcoming these limitations. The workflow combined CAD/CFD analysis, embedded PID control of primary-air delivery, and standardized Water Boiling Tests (WBT). CFD indicated a non-linear emission response: CO mass fraction peaked at a moderate primary-air speed (0.62 m s⁻¹), while cleaner operation required maintaining high combustion temperatures (>1330 °C), underscoring the need for managed airflow rather than simply increasing draft. Thermal simulations and measurements showed steep radial attenuation with scoria insulation, enabling safe hot-core operation of a hot core while maintaining outer wall temperatures around 80 °C. Using CFD analysis, a non-linear relationship between CO emissions and primary-air speed was identified, with peak emissions occurring at moderate airflow (~0.62 m/s). This highlights the importance of managing airflow rather than merely increasing draft. Water Boiling Tests (WBT) revealed an average thermal efficiency of 34.2%, nearly double that of traditional sigiri stoves, with a specific fuel consumption of 0.098 kg of charcoal per kg of water a marked improvement over common baseline devices. The embedded PID control effectively maintained a 600 °C setpoint, demonstrating stable temperature regulation under dynamic conditions. PID-controlled scoria insulation halves charcoal use by UGX 810,000 annual saving, justifying investment via enhanced thermal efficiency. These findings indicate that integrating locally available materials with automated airflow management offers a sustainable pathway for producing affordable, high-performance cooking stoves that can significantly improve household energy use in the region.