BS EN 62805-1:2017 pdf download.Method for measuring photovoltaic (PV) glass Part 1: Measurement of total haze and spectral distribution of haze.
This part of IEC 62805 specifies a method for measurement and calculation of the total haze and the spectral distribution of haze of glass used in photovoltaic (PV) modules.
This document is applicable to glass used in PV modules, including transparent conductive oxide coated (TCO) glass and other kinds of glass used in PV modules.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60904-3:2016, Photovoltaic devices — Part 3: Measurement principles for terrestrial photo voltaic (PV) solar devices with reference spectral irradiance data
IEC TS 61836, Solar photovoltaic energy systems — Terms, definitions and symbols
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC TS 61836 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1 PV glass
glass used in PV modules, including cover or front glass, back glass and substrate glass
3.2 transparent conductive oxide coated (TCO) glass
flat glass coated with a transparent conductive oxide film that is used as a conductive layer
4 Apparatus
4.1 General
Both double-beam instruments and single-beam instruments may be used for the haze measurements. The apparatus shall consist of the following elements:
• a stabilized light source. The wavelength range of the light source shall include 280 nm to 1 250 nm. For the single-beam instrument, the voltage of the light source shall be stabilized within ±1 %;
• for the double-beam instrument, an optical system that forms two parallel beams of monochromatic radiation of the same wavelength A and approximately equal radiant flux from the output of the monochromator.
• an integrating sphere fitted with ports and a photodetector. A diameter of the integrating sphere of not less than 150 mm is recommended. (If an integrating sphere with diameter less than 150 mm is used, the total area of the sphere ports shall not exceed 4 % of the internal surface area of the integrating sphere. Unused ports which are closed and covered with the same coating as the rest of the inner walls of the sphere do not have to be taken into account);
• the schematic arrangements of the double-beam integrating sphere and the single-beam integrating sphere used for measurement are shown in Figure la) and Figure ib) respectively. The photodetector is mounted in the photodetector port in a manner that allows It to view with equal efficiency all parts of the sphere. Ingress of stray external light into the integrating sphere shall be prevented.
4.2 Performance of test instrument
The wavelength range of the instrument shall include 280 nm to 1 250 nm.
The spectral bandwidth shall be adjusted to less than the required measuring wavelength interval.
The wavelength accuracy of the instrument shall be within ±0,5 nm from 280 nm to 900 nm, and ±1 nm from 900 nm to 1 250 nm.
In the wavelength range of 280 nm to 1 250 nm, the accuracy of transmittance measurement shall be within ± 0,3 %, and the repeatability of transmittance measurement shall be within
±0,1 %.
Geometric condition for illumination and detection: The angle between normal of the sample and optical axis of the illuminating beam for the measurement should be < 10°. The angle that any ray of the illuminating beam may make with the beam axis should be < 3°.
5 Test specimens
Test specimens shall meet the following requirements:
— Specimens shall be cut from the PV glass sample.
— Specimens shall be free of dust, grease or other contamination.
— Specimens shall be “wall mounted” against the sphere port rather than being center mounted or mounted at a distance from the sphere.
— Specimens shall be large enough to completely cover the entrance port of the integrating sphere.
— Three separate specimens shall be taken from each sample representing different areas of the PV glass.
NOTE While it Is possible to cut tempered PV glass. it is very dIfIcult and requires specialized equipment. Therefore, the test specimen is cut from non-tempered PV glass samples.
6 Conditioning
The test shall be done in an environment maintained at (23 ± 2) C and (40 ± 15) % relative humidity.
The test specimen shall be maintained in the same environment for not less than 4 h prior to measurement unless otherwise agreed between customer or supplier.
7 Procedure
7.1 General
The wavelength range of the measurement shall be at least over the range from 280 nm to 1 250 nm with preferred wavelength intervals of 1 nm, but a coarser interval up to 5 nm is allowed if the resultant haze versus wavelength curve is smooth over the range of interest.
Adequate time shall be allowed for the lamp of instrument to reach equilibration (typical 15 mm to 30 mm of warm-up time).
The scanning wavelength range from 280 nm to 1 250 nm shall be set up first for the instrument before any measurements are performed.
7.2 Measurements of spectral distribution of haze
A spectrophotometer with the integrating sphere as shown in Figure 1 shall be used.BS EN 62805-1 pdf free download.