The Design and Optical Analysis of Compound Parabolic Collector

For various applications of solar thermal energy, the compound parabolic collector (CPC) is frequently used. To overcome the major limits of a traditional CPC, including a rapid increase in height for a larger aperture width and a low concentration ratio, a modified design was proposed in this paper. This research follows the recent study of Jadhav et al., which used only the region below the common focus of parabolas. Through optical analysis, a design modification was achieved by adjusting the vertical position of the receiver. From the results, setting the height of the receiver to 0.46 times the aperture width was found to permit a greater collection range of incident rays. In addition, a better method for evaluating the performance of the CPC was proposed using an intercept factor to account for the total reflection phenomenon caused by the receiver. By applying the approach to different cases of focal length, it was shown that the concentration ratio was not strongly affected by an increasing focal length owing to the low correlation between the concentration ratio and focal length.