基于Macleod软件的辐射制冷薄膜系优化分析

从基尔霍夫定律和光学薄膜理论出发,利用光学设计软件Macleod,尝试了在铝基上镀单层和多层光学膜系,以满足辐射制冷的要求。选择了合适的膜层材料,在全波段高反射铝基底上设计了单层和多层膜系,运用单纯形法(Simplex)优化了膜层,得到了最优的多层膜结构。膜系的光谱曲线显示,在8～13μm波段具有高的发射率,其余波段具有高的反射率,并且在大的辐射方向角范围(0°～60°)具有稳定的光学性能。最后选取法线方向进行数值积分,取辐射体温度为300K时,最优膜系在8～13μm波段的辐射功率为123.7W/m~2,平均发射率为0.836。光学薄膜方法为选择性辐射体的设计提供了理论指导。

ANALYSIS AND OPTIMIZATION OF THIN FILMS FOR RADIATIVE COOLING BY MACLEOD

Based on the Kirchhoff's law and the optical films theory, and selecting proper film materials, the single and multi-layers films on aluminum substrate with high reflectivity in whole wave band were designed by using the optical design software Macleod to meet the demand of radiative cooling. The films were optimized by the Simplex method, and the best multi-layers film was obtained. The results show that the films possess high emissivity in the wave band of 8 -13μm, and high reflectivity in all other bands according to the reflection curve of the best design, and these characters are maintained in a large range of incidence angle (0°- 60°). When the temperature of radiative cooling objects is 300K, the numerical integral calculation is conducted for the normal irradiation in 8-13μm. The optimum radiative power is 123.7W/m2 and the average emissivity is 0.836. The study provides theoretical guidance for the radiative cooling design.