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Cooking is one of the remaining challenges in autarkic living. In summer electric cooking from PV is well possible. Nevertheless, long term battery storage to cover the energy demand for electric cooking in winter is not feasible. A superior approach to seasonal PV energy storage is the production of hydrogen by water electrolysis and storage thereof in metal hydrides. With this approach no hydrogen loss is encountered during storage time, volumetric energy density is increased and storage capacity is decupled from power conversion potentially reducing storage cost. When considering hydrogen as energy carrier the possibility of direct conversion to heat by catalytic oxidation becomes practicable. To this accord a novel catalytic diffusion burner for hydrogen, based on highly porous silicon carbide (SiC) ceramic foams, coated with platinum (Pt) as catalyst has been developed at Empa and integrated into a cooking stove.
Hydrogen cooker in action
Catalytic hydrogen burner development
Highly porous SiC plates are coated with platinum as catalyst to ensure a catalytic combustion reaction. In this way, hydrogen can be supplied from the bottom of the porous SiC plate and air from the top. Fuel and oxidant thus mix only in the porous combustion area. Uncontrolled combustion is prevented and high passive safety measures are reached. Hydrogen is immediately oxidized by the redox reaction of hydrogen with oxygen.
Catalytic diffusive hydrogen burner setup. Hydrogen is supplied from below, air is supplied between the 2 catalytic areas.
Hydrogen stove development
In the development of the hydrogen stove a hydrogen burner as described above was integrated into a specially designed casing and covered with a glass ceramic top. A heat exchanger was included to preheat the incoming air with the exhaust air leading to a significant improvement in efficiency and reduction in exhaust temperatures. The complete system is fastened to the glass ceramic top and can be integrated into a kitchen counter top. Common thermal safety features as implemented in an electric glass ceramic stove were used.
Left: Expanded picture of the hydrogen stove. Right: Outer dimensions of the hydrogen stove (400 mm by 290 mm by 94 mm).