A modular improved biomass cookstove design: Integrating heat recovery, enhanced efficiency, and fuel flexibility for sustainable energy transitions and emissions reduction

• IBCS integrates adjustable chamber, water jacket, cyclone separator, and insulation. • Wood chips show optimal combustion and fuel use, while leaves perform poorly. • Achieves 38% thermal efficiency (simmering), double TBS’ efficiency (10–20%) • 22% faster cooking and versatile for household use. • Oven retains more than 50°C for 3–4 h post-cooking. Over 2.4 billion people globally rely on inefficient traditional biomass stoves (TBS), contributing to deforestation, household air pollution, and climate change. These issues stem from poor combustion efficiency, excessive fuel consumption, and lack of waste-heat recovery. To address this, we developed a completely new modular Improved Biomass Cookstove (IBCS) uniquely integrating a height-adjustable combustion chamber with forced convection, a heat-recovery water jacket, a cyclone separator, an oven, and insulation, a combination absent in TBS designs. Proximate analysis showed that wood chips had the lowest moisture content (6.3%) compared to branches and leaves. This study evaluates cookstove performance using the Water Boiling Test (WBT), Controlled Cooking Test (CCT), and emission analysis, comparing three stove types and multiple fuels for the developed IBCS prototype. The proposed cookstove demonstrated thermal efficiencies of 19.50% (cold start), 30.00% (hot start), and 38.00% (simmering), double that of TBS performance (10–20%), with 22% faster cooking than that of TBS. The water jacket retained >50°C for 3–4 h post-cooking. Firepower maxed at 8547 W (hot start), enabling rapid boiling. IBCS outer-surface temperature measurements confirmed the effectiveness of insulation. Given the cyclone separator’s negligible effect in our experiments, the design with a provision for a filter showed lower emissions while using wood chips. The modular design accommodates natural, forced convection and diverse fuels, with wood chips outperforming high-moisture leaves. It can contribute to clean energy transitions, sustainable biomass use, and the reduction of emissions, climate impacts, and health risks.