| Popis: |
Publisher Summary The need for accurate evaluation of solar gain through glazed apertures requires knowledge of the angular dependence of the optical properties. This combined with the angle of solar irradiance allows for a rigorous analysis of the direct solar gain enabling improved energy performance modeling. The need to know the angular dependant optical properties of glass and window products has increased with the use of advanced glazing materials, such as solar gain control and low emittance coatings. This chapter presents the design and performance of a unique variable angle reflectance and transmittance accessory developed within our laboratory. The accessory is coupled to a Fourier Transform uv/vis/nir/ir spectrophotometer and is capable of measurement of the absolute spectral optical properties of non-scattering samples at both solar and thermal wavelengths. Measurements at wavelengths from the ultraviolet to the thermal infrared have been validated through a series of inter laboratory comparisons within the European Union ADOPT program and with the UK National Physical Laboratory. Common sources of error, calibration materials, and recommendations for the accurate measurement of optical properties at near normal and oblique incidence are identified in the chapter. |
