Optical features are an essential element in terms of the efficiency of equipment used for solar radiation. A high level of transmission is important for windows and collector covers and a high level of solar radiation and low emissions of thermal radiation are decisive factors for absorbers used for thermal purposes. These values can be determined by spectral measurements with extremely complex, so-called optical spectrometers which measure the physical values of transmission and reflection independently from the wavelengths.

In the optics and infrared optics laboratories the transmission of transparent collector covers and the absorption and emission level of absorbers are determined. Furthermore, the optical characteristics of transparent and opaque materials (reflector materials, windows, transparent plastics, selective layers) are identified. A testing station of this type, specifically for materials which are used in solar technology, is not yet in operation in Austria.

UV/VIS/NIR Spectrophotometer JASCO V-570:

Light sources: deuterium and halogen lamps, single monochromator.

Dual radiation device with a detector consisting of a photomultiplier tube and a Pbs photoconductive cell, wavelength range 200 nm to 2,500 nm (corresponds to a wave number range of 50,000 cm-1 to 4,000 cm-1).

FT/IR Fourier Transformation Infrared Spectrometer JASCO 400:

Infrared light source, Michelson Interferometer, Corner Cube Spiegel, radiation device, special MCT detector,  wavelength range 2,500 nm to 13,000 nm (corresponds to a wave number range of 4000 cm-1 to 770 cm-1).

Integrating balls are also available for UV, the visible and infrared spectral range for the measurement of hemispherical reflection and transmission capacity. All measurements including reflectance can thus be aligned and determined diffusely.

A further application is the determination of the optical characteristics of transparent and opaque materials (reflector materials, windows, transparent plastics, selective layers).  

Sample measurements

Sample size for absorption measurements: min. 3.5 x 3.5 cm², max. 10 x 5 cm² 
Sample size for transmission measurements: max. 2.5 x 6 cm²

If it is not possible for a sample to be taken, for example in the case of hardened solar glass, the transmission level of the original cover is determined by means of a pyranometer (ISO First Class) with natural or artificial radiation. However, the spectral dissolution of the measurement result is not possible in this case.


Patrick Kefer
Ringstraße 43a, A-4600 Wels
Tel: +43 5 0804 46915
Mobil: +43 664 80484 46915

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