DIN EN 62788-1-4
; VDE 0126-37-1-4:2017-08
Measurement procedures for materials used in photovoltaic modules - Part 1-4: Encapsulants - Measurement of optical transmittance and calculation of the solar-weighted photon transmittance, yellowness index, and UV cut-off wavelength (IEC 62788-1-4:2016); German version EN 62788-1-4:2016
Messverfahren für Werkstoffe, die in Photovoltaikmodulen verwendet werden - Teil 1-4: Verkapselungsstoffe - Messung der optischen Transmission und Berechnung der solargewichteten Photonentransmission, des Vergilbungsindex und der UV-Grenzfrequenz (IEC 62788-1-4:2016); Deutsche Fassung EN 62788-1-4:2016
Overview
This International Standard provides a method for measurement of the optical transmittance of encapsulation materials used in photovoltaic (PV) modules. The standardized measurements in this procedure quantify the expected transmittance of the encapsulation to the PV cell. Subsequent calculation of solar-weighted transmittance allows for comparison between different materials. The results for unweathered material may be used in an encapsulation manufacturer's datasheets, in manufacturer's material or process development, in manufacturing quality control (material acceptance), or applied in the analysis of module performance. This measurement method can also be used to monitor the performance of encapsulation materials after weathering, to help assess their durability. The standardized measurements are intended to examine an interior region within a PV module, for example without the effects of oxygen diffusion around the edges of the cells. Subsequent calculation of yellowness index allows for quantification of durability and consideration of appearance. The change in transmittance, yellowness index, and ultraviolet (UV) cut-off wavelength may be used by encapsulation or module manufacturers to compare the durability of different materials. The responsible committee is DKE/K 373 "Photovoltaische Solarenergie-Systeme" ("Photovoltaic solar power systems") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.
