- 學位論文
使用時域有限差分法模擬分析太陽熱光伏系統
Design and analyze Solar Thermophotovoltaics system via Finite-Difference Time-Domain method simulation
若您是本文的作者，可授權文章由華藝線上圖書館中協助推廣。
摘要
因低於能隙的光子無法貢獻電流或輸出電壓過小等機制而導致的能量流失，一單結太陽能電池的效率會有一極限值，即肖克利-奎伊瑟極限(Shockley-Queisser limit)。在此研究中，我們嘗試設計一太陽熱光伏系統來越過此一極限。此系統由吸收器，放射器及一太陽能電池組成。我們以時域有限差分法來模擬吸收器及發射器的效率表現，並結合二者來尋找系統的最佳效率表現。吸收器設計為鎢製錐狀光柵結構，用以得到廣角及大範圍波長的吸收表現。放射器為一鎢板加上多層矽/二氧化矽結構，用以阻斷低於太陽能電池能隙的輻射來減少能量流失。我們以複共軛極點殘差對法(complex-conjugate pole-residue pairs method)來計算材料在時域模擬中的吸收與散射，並以摺積完美匹配層(Convolutional Perfectly matched layer)邊界條件來吸收散射光以確保結果之精確度。本研究並進一步探討不同形狀之接收器設計與不同配置之放射器設計並觀察其吸收的效率與放射之頻譜變化，進一步探討太陽熱光伏系統的改良方向與效率提升的可能性。
並列摘要
Solar photons below band-gap, which leads to no contribution to electrical current, or solar photons above band-gap but has an output energy at most equal to the band-gap, these kind of mechanisms leads to an efficiency limit for single-junction solar cell, as the Shockley-Queisser (SQ) limit. In this study, we try to design a solar thermophotovoltaics (STPV) system to surpass this limit. This system is consisted with an absorber, an emitter and a Si PN junction solar cell. We use the finite-difference time-domain method to simulate the efficiency performance of the absorber and emitter, and combined them to find the best efficiency performance for the system. The absorber is a tapered tungsten grating, which is designed to provide wide angle and broadband absorbing performance. Emitter is a tungsten slab with Si/SiO2 multilayer stack to suppress sub-band-gap radiation and reduce energy loss. We use complex-conjugate pole-residue (CCPR) pairs method to calculate dispersion and absorption of the material in time-domain simulation, also using the convolutional perfectly matched layer (CPML) absorbing boundary condition to truncate the grid space and assure the accuracy of the result. This study also explores different-shaped structures for the absorber and different-layered structure for the emitter to optimize the absorbing efficiency and emitting spectrum, and further explores the possibility of improvement of the STPV system efficiency to exceed the SQ limit.
參考文獻
W. Shockley and H. J. Queisser, "Detailed Balance Limit of Efficiency of p-n Junction Solar Cells," Journal of Applied Physics, vol. 32, no. 3, pp. 510-519, 1961.
B. D. Wedlock, "THERMO-PHOTO-VOLTAIC ENERGY CONVERSION," Proceedings of the Ieee, vol. 51, no. 5, pp. 694-&, 1963.
W. Spirkl and H. Ries, "Solar thermophotovoltaics: An assessment," Journal of Applied Physics, vol. 57, no. 9, pp. 4409-4414, 1985.
P. T. Landsberg and P. Baruch, "The thermodynamics of the conversion of radiation energy for photovoltaics," Journal of Physics a-Mathematical and General, vol. 22, no. 11, pp. 1911-1926, Jun 1989.
T. K. Chaudhuri, "A solar thermophotovoltaic converter using Pbs photovoltaic cells," International Journal of Energy Research, vol. 16, no. 6, pp. 481-487, Aug 1992.