Hydrogen and wood-burning stoves

Wood-burning stoves, in Kenya and Mexico, are reviewed. With a Kenyan stove, burning charcoal, only 24% of the energy released reached the cooking pot. Initially, the proportion of CO in the leaving gases was 3%. Indoor concentrations of particulate matter (less than 2.5 µm diameter) can be abnormally high near a stove. Decarbonization, by using H₂, is facilitated by a distribution system. Replacement by H₂ would ultimately rest upon wind or water power, or it being a by-product in the production of heavier hydrocarbons from CH₄. The averaged burning rate in the Kenyan stove was 10 kW, over 20 min, with an initial peak value of about 30 kW. A possible replacement is a hob, composed of an array of small diameter H₂ jet flames. As an example, combustion of a 2 mm internal diameter H₂ jet flame, with a H₂ exit velocity of 27.2 m s^-1, would release 0.84 kW. Bearing in mind its improved efficiency, a single compact hob with an array of about 10 jets would suffice. A difficulty is the low mass-specific energy of H₂. H₂ has a high acoustic velocity, and both high velocity subsonic combustion and blending with natural gas are briefly discussed. This article is part of the theme issue 'Developing resilient energy systems'.