全平面镜线反射太阳聚光器的光学设计

Optical design of a linear reflecting solar concentrator with all-flat mirrors

为了降低太阳能聚光器的成本,在线聚光菲涅耳集热器中常使用平面镜作为反射镜的组成元素。根据菲涅耳线聚光理论,提出了使用全平面的窄条镜按一定角度布置于跟踪托架上构成不同焦距的初级反射镜单元,由多块跟踪镜单元组成初级反射镜场的设计方法,采用新的次级反射器设计思路,设计了双圆弧形二次反射聚光器。采用平板玻璃镀银镜为初级反射镜材料,设计制作了试验装置,从光线跟踪模拟和实际试验都具有很好的聚光效果。该反射镜单元的设计具有低成本、聚光效果好、可扩展集热器场宽度、跟踪稳定和抗风载等优点,小规模集热器可用于蒸汽生产,提供农产品干燥等所需的过程热,大规模的集热器可以用于热发电所需的预热蒸汽或直接用于热发电。

In order to reduce the cost of solar concentrating collectors, flat mirrors were used to make reflectors in line focusing Fresnel collectors. Based on the optical principle of linear Fresnel concentration, several flat narrow silvered mirror strips were used to make a reflecting mirror unit on a tracing device. The primary mirrors of linear Fresnel collector were consisted of reflecting mirror units with different focal lengths. With new idea of receiver design, a double-arc secondary reflector was designed in order to collect more radiation and lessen the aperture of the receiver. Good results were obtained from the simulation of ray trace and experiments of testing device. The design of the reflecting mirror unit has the advantages of low cost, good sunlight concentration, expandable primary mirror field, very low wind load and stable tracing. The small scale concentrators can be applied to steam generation which can provide process heat for agricultural products drying. The large scale concentrators can provide steam for thermal electricity.