极轴式定焦点菲涅尔聚光器设计及焦斑位置偏差研究

DESIGN OF FIXED-FOCUS FRESNEL LENS SOLAR CONCENTRATOR USING POLAR TRACKING AND STUDY ON FOCAL SPOT POSITION DEVIATION

基于菲涅尔透镜的聚光特性和极轴跟踪原理,提出一种能实现定焦点聚光的太阳能聚光器,详细分析聚光器的定焦点聚光原理,并搭建实验平台对其聚光焦斑位置偏差进行红外热成像分析。实验结果表明,全天聚光焦斑相对位置偏差最大值为5.72%,且焦斑基本分布于以基板中心为圆心、半径50 mm的圆环区域内,即实现定焦点聚光。同时利用TracePro值为3.56%,且焦斑分布情况与实验基本一致。结合全年太阳赤纬角的变化,对真太阳时为08:00～16:00的聚光焦斑位置偏差情况进行模拟分析,结果表明该聚光器的全年聚光焦斑相对位置偏差最大值为4.84%,进一步验证了聚光器能实现全年定焦点聚光。

A type of fixed-focus Fresnel lens solar concentrator using polar tracking is proposed and analyzed,which based on the optical properties of point-focus Fresnel lens and the principle of polar tracking. According to this principle,the experimental platform is built to carry out experiment and simulation study of focal spot. The result of experiment and simulation study indicates that the maximum relative positional deviation of the focal spot in one day are 5.72% and3.56%,respectively. The distribution of the focal spots are basically similar and they are included in the annular region which is centered at the center of the substrate with the radius of 50 mm. In other words,the fixed focus can be achieved in theory and practice,and the simulation study can be used to verifies the fixed focus characteristic of the solar concentrator. Further,with the change of the sun declination angle,the focal spot is studied from solar time 08:00 to 16:00. The simulation results show that the maximum relative position deviation in Guangzhou is 4.84%,which means that the solar concentrator can achieve the fixed focus in the whole year.