Development and testing of a two-axis tracking spherical solar cooker

Solar energy, the clean and non-polluting energy source, has a great potential to supply world's energy needs. It is one of the largest renewable energy resources which is available almost everywhere. There are many fields where solar energy is used such as water & air heating, drying, distillation, cooking etc. But the efficiency of solar systems is less than conventional systems. It might be because of lack of proper technology and high cost to develop efficient system. Solar cooker is a device which is used for cooking food. It is simple, safe and convenient to cook food without consuming conventional fuel. In the previous year a parabolic type spherical solar cooker was designed and constructed. In that cooker, single axis manual tracking was used. In order to improve the efficiency of the cooker, a two axis tracking mechanism was designed and constructed and the cooker was installed on it. But, the motors that were needed for two axis tracking were expensive. So, an alternative manual tracking system was developed that could serve the purpose of facing the collector towards the sun every half an hour. Performance of the cooker has been measured. The maximum temperature inside the cooking pot was found to be 97°C, with a load of 300 g rice and 100 g dal, within 40 minutes at a radiation level of 260-394 W/m2.