Mathematical Model to Study Solar Cookers Box-Type with Internal Reflectors

Abstract A mathematical model to determine the thermal function on a solar cooker box-type with internal reflector as well as one application in numerical simulation for predicting the transitory thermal behavior are shown. The mathematical model validation is carried out when numerical results generated by numeric simulation are compared versus own experimental results and experimental results reported by El-Sabaii and Domanski at Tanta, Egypt. Experimental data obtained by El-Sabaii and Domanski were selected because these were obtained under controlled conditions and their solar cooker prototype is similar to the solar cooker analyzed in this work. For the mathematical model solution, ambient temperature and solar radiation values were used and for this purpose, experimental data were obtained. A device Compact Field Point Model FP-TB-3 to obtain ambient temperature values was used and an Eppley piranometer 8-48 for obtaining solar radiation data was used. The information obtained was processed using the Labview software of National Instruments. A case when the solar cooker is integrated for 3, 4 and 5 steps is considered and the thermal behavior in the solar cooker for this case is evaluated. The main results allow to explain how the increment in the internal steps impacts on the temperatures in the solar cooker. Also is explained how the mathematical model can be used for different applications as different fluids and different liquid amounts. Finally, is pointed out how the numerical techniques can be useful to analyze solar devices as solar cookers box-type.