In this paper, we propose to use glass optical fibers with a rectangular cross-section for the application in a concentrator photovoltaic and daylighting system (CPVD) due to the unique characteristics of rectangular fibers with the capability to provide a uniform rectangular beam shape and a top-hat profile at the output. A mathematical model of rectangular optical fibers has been formulated in this study for different incident angles, and the results are compared with those of round optical fibers. Furthermore, the performance of the bundle of RGOFs is compared with that of the bundle of round optical fibers via simulation by using the ray-tracing method. The mathematical modelling and numerical simulation have demonstrated that the RGOF has advantages in terms of the improvement in relative transmission and reduction in energy leakage for the transmission through the optical fiber. The simulation result also shows that a higher flux of sunlight can be transmitted via the bundle of RGOFs as compared to the bundle of round optical fibers due to the higher coupling efficiency. The experiment results on the relative transmission in different incident angles for both round optical fibers and RGOFs have validated both the simulation and the mathematical modelling. The beam profile of our fabricated RGOF has also been measured via our laboratory facility. The flexibility test on the fabricated RGOF has been carried out to bend at a radius of 150 mm and twist at 90° at a fiber length of 2.2 m.

中文翻译：

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用于在混合聚光器光伏和采光系统中传输阳光的矩形玻璃光纤

在本文中，我们建议使用具有矩形横截面的玻璃光纤用于聚光光伏和采光系统 (CPVD) 中，因为矩形光纤具有独特的特性，能够提供均匀的矩形光束形状和输出中的顶帽配置文件。本研究建立了不同入射角下矩形光纤的数学模型，并将结果与​​圆形光纤进行了比较。此外，通过使用光线追踪方法模拟，将 RGOF 束的性能与圆形光纤束的性能进行了比较。数学建模和数值模拟表明，RGOF在改善相对传输和减少通过光纤传输的能量泄漏方面具有优势。仿真结果还表明，与圆形光纤束相比，RGOF 束可以传输更高的太阳光通量，因为它具有更高的耦合效率。圆形光纤和 RGOF 在不同入射角下的相对传输的实验结果验证了模拟和数学建模。我们制造的 RGOF 的光束轮廓也通过我们的实验室设备进行了测量。已经对制造的 RGOF 进行了柔韧性测试，以在 2.2 m 的纤维长度下以 150 mm 的半径弯曲和 90° 扭曲。