太陽能集光系統包含集光器、太陽能電池與追蹤裝置，在高倍率的集光比下，較大的可接收角將會增加追蹤裝置的容忍度，減少追蹤裝置的成本。當可接收角夠大時，幾乎不需要追蹤裝置就能作為非追蹤式太陽能集光器。二階段式太陽能集光器分成兩個光學元件，第一光學元件使用菲涅爾(Fresnel)透鏡或是拋物面反射鏡(parabolic mirror)作為主鏡匯聚太陽光，第二光學元件的入瞳位於第一光學元件的焦平面上，這樣結合的二階段式太陽能集光器具有高可接收角的特點，dome、Fresnel Kohler(FK)等都可做為第二光學元件。本論文將對二種二階段式太陽能集光器的第二光學元件作深入討論，第一種為Telecentric Compound Parabolic Concentrator(TCPC)，利用拋物線的特性將光匯聚到接收器上，其可接收角在幾何集光比100倍時為7.9˚。第二種為Dielectric Totally Internal Reflection(DTIR)集光器，在離軸上利用光線的全反射原理將大角度的入射光線匯聚到接收器上，設計成透鏡陣列的結構，其可接收角在幾何集光比100倍時為3.8˚。Solar concentrator system includes solar concentrator, solar cell and a tracker. Under high concentrator ratio, a bigger acceptance angle will give rise to looser requirements on tracker tolerance. The need for a tracker may even be eliminated when the acceptance angle is sufficiently big.Two-stage solar concentrator can be divided into Primary Optical Element (POE) and Secondary Optical Element (SOE). POE utilizes a Fresnel lens or a parabolic mirror to focus collected sunlight; whereas SOE, a.k.a. Second Stage Solar Concentrator can be a Dome lens, a Fresnel Kohler lens, etc. The Entrance Pupil of the SOE is placed on the focal plane of POE. This combination provides a high acceptance angle. This thesis discusses about designs of second stage concentrator in two different types of two-stage solar concentrator, Telecentric Compound Parabolic Concentrator (TCPC) and Dielectric Totally Internal Reflection (DTIR). A TCPC focuses light onto the receiver through its reflective parabolic surface. In our design, the acceptance angle is as high as 7.9 degree when the geometrical concentration ratio is 100x.A DTIR concentrator utilizes total internal reflection to focus light onto the receiver. Our design, utilizing lens array, has resulted in a system with acceptance angle 3.8 degree when the geometrical concentration ratio is 100x.
