Experimental analysis on a solar photovoltaic indoor cooker integrated with an energy storage system: A positive step towards clean cooking transition for Sub-Saharan Africa

The paper presents a solar photovoltaic cooking solution (dual tank system) integrated with energy storage system for indoor cooking. The system consists of a heat storage tank, a heating funnel and a cooking unit. The heat storage contains heat transfer oil and rock pebbles. The heating funnel was made in the form of a Y-shape where a small volume of oil is heated very fast to higher temperatures. The system is based on self-circulation; no pump is required. A 1.8 kW solar PV system generated electricity to supply a heater rated 1.2 kW, 72 V mounted inside the heating funnel. The heated oil in the funnel expanded and overflows into the heat storage. It was observed that the oil in the heating funnel reached temperatures of above 150 °C in less than 30 min: the TES system can store up 9.0 kWh. Several cooking tests were demonstrated during charging and discharge processes. 10 L of water was boiled in 25 min consuming 0.986 kWh; 3 kg of rice was boiled in 1 h consuming 0.556 kWh and 1.26 kWh of energy was used for boiling and simmering of 3 kg of beans within 2–3 h. At the top of the cooker a high-temperature heat front was observed. During the discharge cycle, there is no mixing of cold and hot oil. A thermal charging efficiency of 57.4 % was obtained. Cooking efficiencies of 75.0 % and 59.4 % were obtained during charging and discharge cycles respectively. The system highly scalable for indoor household and institutional solar cooking.