Photometry and radiometry
Measurement of luminous and solar characteristics according to EN 410
Measurement of the spectral transmission () and reflection () in the wavelength range between 250 nm and 2500 nm at small samples 40 x 70 mm of single panes in the UV-VIS-NIR- spectrometer Typical spectral transmittance The spectrum of the sun 100 UV Sichtbar Infrarot 90 5% 50% 45% 80 100 ideale selektive Transmission 70 80 60
50 Float glass 60 Thermal protection layer Sonnenspektrum 40 Solar control layer 2 40 I = 1kW/m 30 20
20 % in Transmissionsgrad
10 relative spektrale Intensität in % 0 0 200 600 1000 1400 1800 2200 0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 Visible area 380-780 nm Wavelength Wellenlänge in nm
100 % Solar energy
q = 16 % The following values can be measured and/or calculated for glasses i The luminous values of qa = 12 % insulating glass units are g total solar energy transmittance (g==e+qi) v light transmittance determined calculative on basis of the measured solar transmittance light reflectance e v single panes. e solar reflectance UV UV-transmittance = 26 % e = 46 % qi secundary heat flow Total solar energy transmittance g = 62%
Measurement of light transmission v and light reflexion v for light diffusing and light channelling products according to DIN 5036 and/or EN 14500
Light diffusing products are e.g. screen-printed glass, etched Picture of the integrating sphere at ift Rosenheim glass, glass with integrated installation and solar control products like fabrics and lamella. For systems that have angle depending characteristics, the radiation angle can vary from 0°to 60°
Measurement principle of the integrating sphere
1 Sample 2 Light D65
Measurement of emissivity n according to EN 12898 Example for the influence of lowE-coating on the Ug-value
Every body radiates heat. The emissivity of a body indicates how much radiation it gives compared with an ideal radiant Air Air Argon warmers, a black body. Radiation
Conduction
The emissivity n of the surfaces has among other things influence on the Ug-value of the insulating glass unit; the lower Convection IR- the emissivity, the lower the Ug-value. reflective coating Typical values for nare: Standard float glass 0.89 a i a i a i Solar control coating 0.02 Thermal insulation coating 0.03 - 0.06 Ug = 3.0 W/(m2.K) Ug = 1.5 W/(m2.K) Ug = 1.2 W/(m2.K)
ift Rosenheim GmbH, Theodor-Gietl-Str. 7-9, 83026 Rosenheim, Tel. +49 (80 31) 261-0, Fax: +49 (80 31) 261-290, E-Mail [email protected], www.ift-rosenheim.de