Comparative experimental investigations on a low-cost solar cooker with energy storage materials for sustainable development

Abstract

Solar energy has been the focus of attention in recent decades due to its abundance, inexhaustibility, and cost-effectiveness. To promote solar cooking, a cooking pot integrated with energy storage is developed and studied. It features a concentric cylindrical arrangement, with the inner cylinder used for cooking and the outer cylinder used for energy storage. Solar energy was concentrated using a parabolic dish, with water serving as the load. The thermal performance during non-sunshine hours was analyzed using energy storage media.Initially, four cases were considered. In case 1, no energy storage medium was used, while in cases 2, 3 and 4, pebbles, stearic acid and erythritol were used as the storage medium, respectively. Water was heated to nearly 100 °C, and the results were analyzed for heat retention and temperature variations. The cooking pot using erythritol recorded a maximum instantaneous energy efficiency of 52 % and exergy efficiency of 37 %. In all four cases, the water was maintained at higher temperatures than the surroundings until the next morning, a maximum temperature difference of around 27–28 °C between the load and surroundings was reported during case 3. For high temperature cooking, sunflower oil was used as heating load with erythritol in case 5. A temperature difference of 8–9 °C higher than the case 3 was observed in case 5. Heat loss coefficient for case 4 was lowest i.e., 2.75 W/m2K. The payback period for the cooking unit was around 10 months considering the cost of energy saved and CO2 mitigation.