Design and analysis of Fresnel-lens solar concentrator
chia yu hu
|關鍵字:||菲涅洱透鏡;集光因子;非聚焦;高效率光電轉換系統;均勻;太陽能電池;Fresnel lenses;concentration ratio;nonimaging;hcpv;uniformity;solar cell|
|摘要:||光電轉換(PV or Photovoltaic)集光系統的目標是為利用光學元件提升整體光電轉換的效率，以降低每單位pv系統的集光成本，從而提高在太陽能電池的每單位元光能量密度。利用光學元件集光系統可以減少整體太陽能集光系統對昂貴矽太陽能電池的依賴性，並達到良好的效率。而太陽能集光系統的研究致力於(1)光能量在太陽能電池上的光能量分佈良好均勻度和(2)集光器對太陽光的大收光角。在其中折射式的菲涅洱透鏡(Fresnel lenses)是被廣為使用的一種聚光鏡。本論文之探討主題即是分別為擁有高容忍度角優勢的拱型菲涅洱聚光鏡與能量分佈能有均勻表現的平板式的菲涅洱透鏡。模擬5度容忍度角內的菲涅洱聚光鏡，並分析拱型菲涅洱透鏡的組成元件稜鏡中的各項性質。在目前以平板菲涅洱透鏡為主流的情況下，並設計了集光後在太陽能電池(Solar cell)上的能量分佈能有均勻表現為主要訴求的平板式的菲涅洱非集光式(non-imaging)透鏡。平板菲涅洱透鏡的稜鏡寬度過寬時，會造成太陽能電池分佈上能量較不均勻的情形，因此引入了平板菲涅洱透鏡中心置換非球面的想法考量，透鏡聚光後能量在太陽能電池上的分佈情形。置入非球面後，確有將均勻度提高的明顯作用。|
The major aim of photovoltaic (PV) concentrator technology is to improve the PV array performance per cost unit by concentrating optical components to increase the intensity of sunlight falling on the cell. By using concentrator it is possible to decrease the area of solar cell material being used in a system and therefore to reduce the dependence of the PV industry on the silicon stock imitations as well as reaching very high efficiencies, with sophisticated high cost cells. Better uniformity performance on solar cell and larger angular acceptance of field of view of concentrator system are the two major targets of research and development in constructing the optical concentration systems. On the other hand, the use of Fresnel lenses has been the main stream for optical concentrators because of its flexibility. The subject of this thesis study is to provide the design analysis of the Dome-shaped and Plated-shaped Fresnel concentrators in which dome-shaped concentrator has larger tolerance in light collection angle, while the planer-shaped has better performance in uniformity of energy distribution on solar cell. As a basic investigation, the role of single base prism in both types of Fresnel lenses has been clarified. The main results of this thesis are that we explored and designed the dome-shaped concentrators which can have tolerance angle upto 5 degrees. As for the plated-shaped Fresnel concentrator, because of the fabrication limitation of pitch size and the consideration of compact system, high non-uniformity of energy on solar cell is inevitable, hence we introduced aspheric surface in the middle portion and it is shown that better uniformity could be achieved significantly.