Development and performance studies of a novel portable solar cooker using a curved Fresnel lens concentrator

Solar cookers use clean and accessible solar energy to heat food. They provide a new choice for outdoor cooking for users. However, currently available solar cookers now have some weaknesses such as being too big to carry, low heating temperature and overlong cooking time. To overcome these problems, this paper designs a novel portable solar cooker using a curved Fresnel lens as the concentrator. This novel solar cooker can focus sunlight onto an evacuated tube collector to heat the food here. It has a high concentration ratio and allows tracking the sun in both zenith and azimuth angles manually, therefore it is possible to get higher cooking temperature and shorten the cooking time. In this paper, the structure and working principle of the device are introduced. The optical performance of the system is simulated by a software and the heat transfer model of the system is established and presented. Experimental studies have been carried out, and the variation of maximum temperature of the system during the day under no-load condition has been obtained. Moreover, to test the system performance, the theoretical maximum temperatures of the system with no-load condition under different irradiances have been calculated. Results indicate that when direct irradiance is I = 712 W/m(2) the obtained highest average temperature of the system without load can reach at about 361 degrees C. Besides, the performance of the solar cooker has been tested on four kinds of 0.5 kg representative foods, namely, sweet potato, pork (all lean), yam and radish. Results show that cooking time of pork is the shortest (only 34 min), and radish is the longest (64 min). All cooked food reaches the edible standard.