Design and energy assessment of non-premixed gas burners: Radiative and catalytic hydrogen combustion

Hydrogen is a combustion fuel that does not generate carbon-based combustion (by-)products. It has been considered as a clean cooking fuel to combat indoor air pollution. We propose and fabricate a compact, hydrogen-fueled radiative catalytic cooking stove and assess the energy balance in a dedicated test bench. The design was developed focusing on compactness and ease of manufacturing. Simulations helped to develop an ideal, perforated gas distribution system, maximizing pre-combustion fuel mixing. Homogeneity of the combustion was improved experimentally by an empirical tuning method applied to the gas distribution system. We addressed the lack of detailed energy flow assessments in existing studies by developing a test bench that allows to quantify all major losses, including exhaust, insulation, pan and unburnt fuel as well as assessing the impact of initial state conditions. We also apply standard Water Boiling Test (WBT) protocols and critically evaluate the applicability of WBT metrics to real-use cooking conditions. The stove efficiency according to the ISO standard water boiling test was 37%. We observed that a large part (26% up to 40%) of the generated combustion heat leaves as hot exhaust gas. The stove has the potential to reach a maximal efficiency of 72% (high heating value based) if advanced exhaust heat recovery is implemented. Other approaches (including variations in operating conditions and insulation) only affected the energy flux distribution but not the efficiency. We offer guidelines for the advancement of hydrogen-powered stoves in terms of design and in terms of energy evaluation of the cooking process.