Design, Fabrication and Performance Evaluation of Parabolic and Enhanced Solar Box Cookers in Isimani, Tanzania

Abstract

Clean cooking energy is a global priority, especially in developing countries where firewood and charcoal remain the primary cooking fuels. Solar cooking is an attractive alternative in these countries since it is eco-friendly and utilises freely available solar radiation. Utilisation of solar cookers however is still very low mainly due to the perceived complexity and lack of confidence in the available solar cooker models. In this work, the enhanced box and parabolic solar cookers were designed, fabricated and tested taking into consideration standard solar cookers and local cooking requirements. The enhanced box solar cooker was designed with booster mirrors making an effective aperture area of 0.68 m2, a double glass glazing and a glass wool insulator between the double walls of the cooking box. The parabolic cooker was designed with polished aluminium paraboloid with a net aperture area of 1.44 m2, a parabola depth of 0.47 m and manual solar tracking. In field tests in Isimani Tanzania, the enhanced solar cooker attained a maximum temperature and cooking power of 129.8 °C and 101.9 W, respectively, and was able to boil 2 litres of water in 100 minutes. The parabolic cooker on the other hand registered a maximum cooking power of 513 W at solar noon and was able to boil 2 and 5 litres of water in reasonable times of 30 and 60 minutes, respectively. Keywords: Clean cooking, parabolic solar cooker, enhanced box solar cooker, polished aluminium, cooking power