Design and Experimental Study of a Hemispherical Solar Cooker: Application to Food Cooking

Abstract

The present work is an experimental study of a glazed hemispherical solar cooker. It consists of a hemispherical concentrator made of reinforced concrete with a smooth inner part lined with a self-adhesive aluminium mirror film with a reflectivity of 95%. This reflector enables all the sun rays to be reflected onto the absorber. The hemisphere has a radius of 0.59 m, a height of 0.46 m and an exposure area of 0.1535 m2 for the half angle of the apex of the focus with the axis passing through the centre. Experimental data on the evolution of the temperature of the air trapped in the device on October 26, 2022 showed a maximum temperature of 63°C. The temperature under the glazing indicates a maximum value of 51°C, for an ambient temperature of 35°C. The maximum irradiation of 700W.m-2 obtained around 11:45 a.m. The second test, carried out on October 28, 2022, was designed to heat 1.5 litres of water. The results indicate a maximum temperature of 91.7°C for the water, obtained from 10.45a.m and 1.33pm. However, the air temperature under the glazing gave a maximum value of 67°C. The ambient air temperature was 37°C. The day of April 21,2023 is devoted to experimental studies on cooking and frying sweet potatoes. The maximum temperature was 97°C, obtained from 11:30 a.m, for an air temperature of 80°C under the glazing, obtained from 10:50 a.m. with maximum irradiation of 957.1 W.m-2. A value of 130°C is obtained at 13:21pm for the oil heating test and a maximum temperature of 68°C for the internal air at an ambient temperature of 32.9°C. The irradiation value reached a maximum of approximately 306.8W.m-2.