A vector based freeform approach for reflecting concentrator of solar energy. (1st September 2017)

• Record Type: Journal Article
• Authors: Meng, Xian-Long; Xia, Xin-Lin; Dai, Gui-Long; Guene Lougou, Bachirou; Wu, Shuai-Long
• Is Part Of: Solar energy. Volume 153(2017)
• Page Start: 691
• Page End: 699
• Publication Date: 2017-09-01
• Subjects: Solar concentrator -- Freeform surface -- Ray tracing -- Uniformity; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2017.05.070
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: A new control approach for the solar heat flux on CPV is proposed. It is based on 3-D freeform optics and also considers solar cone angle effect. It is a close-loop program that do not need any other software or file operations. The solving procedure involves source-target mapping, GCM, MCRT, and feedback modifications. An improved MCRT is proposed to accelerate the solving through solar cone constraint. The approach is validated by the examples of target circular or rectangular receivers. Abstract: A vector based freeform approach is proposed for the geometrical reverse design of reflecting solar concentrators. The effect of solar cone angle of incident vectors is taken into consideration in the method based on three-dimensional freeform optics. The method developed is a closed-loop program and did not need any other commercial software. According to the transmission pattern of solar concentrators, the source-target mapping should be initially established prior to constructing an initial geometry formed by discrete points using the Geometric Construction Method. The freeform surface is generated by connecting several triangular flat elements defined by these points and then the Monte-Carlo ray tracing was conducted. The freeform surface can then be further optimized through feedback modifications. Finally, the optimal shape is obtained when the design examples are the off-axis freeform reflectors with target circular/rectangular receivers for the use of Concentrated Photovoltaic. This method provides a practical approach for improving the optical performance of solar concentrators.