Tesfamichael T, Wäckelgård E
Department of Materials Science, Solid State Physics, Uppsala University, Box 534, S-751 21 Uppsala, Sweden.
Appl Opt. 1999 Jul 1;38(19):4189-97. doi: 10.1364/ao.38.004189.
The optical characterization of solar absorbers for thermal solar collectors is usually performed by measurement of the spectral reflectance at near-normal angle of incidence and calculation of the solar absorptance from the measured reflectance. The solar absorptance is, however, a function of the angle of incidence of the light impinging on the absorber. The total reflectance of two types of commercial solar-selective absorbers, nickel-pigmented anodized aluminum, and sputtered nickel nickel oxide coated aluminum are measured at angles of incidence from 5 to 80 in the wavelength range 300-2500 nm by use of an integrating sphere. From these measurements the angular integrated solar absorptance is determined. Experimental data are compared with theoretical calculations, and it is found that optical thin-film interference effects can explain the significant difference in solar absorptance at higher angles for the two types of absorbers.
用于太阳能集热器的太阳能吸收体的光学特性通常是通过测量近垂直入射角下的光谱反射率，并根据测量的反射率计算太阳能吸收率来进行的。然而，太阳能吸收率是入射到吸收体上的光的入射角的函数。使用积分球在300 - 2500 nm波长范围内，在5至80度的入射角下测量了两种商用太阳能选择性吸收体的总反射率，这两种吸收体分别是镀镍阳极氧化铝和溅射镍镍氧化物涂层铝。根据这些测量结果确定角积分太阳能吸收率。将实验数据与理论计算进行比较，发现光学薄膜干涉效应可以解释这两种吸收体在较大入射角下太阳能吸收率的显著差异。
