Influence of the Mirror Reflectance Coefficient on the Performance of the Compound Parabolic Trough Concentrator (CPC): Numerical and Experimental Simulation in a Sahelian Environment

The objective of our study is to numerically and experimentally simulate the CPC operation according to three different values of the mirror reflectance coefficient. The study not only showed the importance of mirror reflectance in the performance of solar collectors but also estimated which of these three values fits well with the reality in the city of Ouagadougou. The thermal exchanges that took place in the CPC were presented. A matlab program was developed for the calculation and simulation of the different parameters of the solar concentrator. The differential equations governing the heat transfers in the different components of the device were discretized by the advanced finite difference method. They were solved by the Gauss-Seidel method. As for the experimental part, it consisted in the direct measurement of the global solar radiation, of the ambient temperature and of the fluid temperature by means of thermocouples placed on the different parts of the sensor. The experimental values are directly recorded with a datalogger. A statistical study was made using some indicators like coefficient of determination of  R2 , root mean square error (RMSE) and percentage of mean absolute error (MAPE). A validation of the obtained results by comparing the calculated values with the experimental values was presented. The results show that among the three values of the reflectance coefficient, the best results on the temperature of the fluid are obtained with the reflectance coefficient equal to 0.68 on the site of Ouagadougou.