CPC空隙设计及光能损失

复合抛物面聚光器（Compound Parabolic Concentrator，CPC）因结构简单不需要跟踪等优点在太阳能集热器和光伏发电系统中已获得广泛的应用，理想CPC的反射面与吸收体连在一起，而实际应用中因种种原因必须在两者之间留有空隙。该文对三种常见的CPC空隙带来的光学损失进行了理论分析。对比分析结果表明：对于平面吸收体CPC，空隙设计的优选方案是剪去靠近吸热体的反射面；对于圆形吸收体CPC，最优选的空隙设计方案是对理想CPC所对应的受光体的形状进行修正，其次是剪去与圆管相连的反射面。

Gap design and optical losses of compound parabolic concentrators

Compound parabolic concentrators (CPCs) have been widely used in solar thermal and photovoltaic electricity generating systems due to their simple structure without any tracking system. The reflectors of a typical ideal CPC contacts the absorber at the ends of absorber, but a gap must be left between the absorber and reflectors for practical applications due to practical requirements. In this article, three common design options of CPCs were presented and the optical losses through gaps were theoretically analyzed. A comparison of gap losses for three design options of a CPC was also made. The results showed that, for CPCs with flat absorbers, the preferable design option of gaps for minimizing optical loss was to truncate the reflectors adjacent to the absorber; for CPCs with a tubular absorber, the best way was to modify the virtual absorber of ideal CPCs to accommodate the actual tubular absorber so that a gap could be produced, the next was to truncate the reflectors near the absorber.