文档介绍：摘要
高倍聚光太阳能光伏光热系统将太阳能电池作为集热器,可以同时获得电能和热能,并且可以大幅降低太阳电池组件的温度,解决因温度过高而导致的光电转换效率下降的问题。然而,传统菲涅尔透镜聚焦光斑的均匀度较差,会导致电池转换效率降低,并且接受角较小,对跟踪系统精度要求较高;同时,由于较高的温度变化而产生的热应力电池,对电池的寿命和可靠性造成影响。为此,本文对菲涅尔透镜均光系统进行设计,改善光斑分布均匀度,同时模拟分析高倍聚光条件下太阳能电池的温度和热应力分布,为高倍聚光太阳能光伏光热系统的改进提供依据。
本文根据几何光学原理和光线追迹理论设计了三级聚光结构,并对比分析了三级聚光结构和传统单一菲涅尔透镜聚光的性能差别。同时,建立光电光热系统模型, 将聚光分析结果作为边界条件,模拟计算了高倍聚光太阳能电池在不同条件下的温度场分布,比较了不同条件下电池的温度变化以及热应力变化。主要结论有:
三级聚光结构能够改变光斑形状,使光斑与电池形状相同减少浪费,并使得光斑均匀度由单一菲涅尔透镜下的 %提高到 %,同时可以增大接受角,并且在使用玻璃硅橡胶为透镜材料可以尽量减小能量损失;
***化镓电池的稳态温度场分布为中心位置温度高,边缘位置温度低,非均匀热流密度条件下,温度场分布与均匀分布时相似;在实际应用中,随着太阳直射辐照度不断变化,要使出口流体温度保持在一定范围内,需要调节入口速度,同时存在最佳入口速度;
在均匀辐照度条件下,垂直方向 MgF2 层热应力最大,水平方向四层结构都是中心处热应力较大,边缘处热应力迅速降低,在不同辐照度条件下,热应力随着辐照度的增大而增大。
关键词:聚光光伏光热,菲涅尔透镜,三级聚光,***化镓电池,热应力
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ABSTRACT
solar cells as a collector in high concentrated solar photovoltaic solar-thermal systems can obtain electricity and heat at the same time. It can greatly reduce the temperature of the solar ponents and solve the decline of the photoelectric conversion efficiency. However, the traditional Fresnel lens focused on the poor uniformity of the light spot. It can reduce the battery conversion efficiency, and receiving Angle is small, high accuracy requirement for tracking system. At the same time, the thermal stress of the battery because of the high temperature can destroy the battery life and reliability. Therefore, this paper redesign the Fresnel lens optical system, improve the light distribution uniformity, and analysis of solar cell temperature and thermal stress under the condition of high power condenser provides the basis for improvement for the high concentrated solar photovoltaic solar-thermal systems.
Based on the principles of geometrical optics and ray tracing theory triple concentrated structure was designed, and the contrast analysis of the triple structure of condenser and traditional single Fresnel lens condenser performance difference. At the same time, the concentrated photovoltaic solar-thermal system model is establish