6

a glazing

Controlling light and heat - the selective glazing

solar-control

Heat entering a building is entirely due to solar radiation, which can be broken down into three types of radiation (fig. 2):•

Ultraviolet (UV) radiation:

from 280 to 380 nm, i.e. around 5% of the total energy of the solar spectrum.•

Visible radiation (visible light):

from 380 to 780 nm, i.e. around 50% of the total solar spectrum.•

Short infrared radiation:

from 780 to 2500 nm, i.e. around 45% of the total solar spectrum.The smart coatings used in Thermobel Stopray solar-con-trol glazing filter out solar radiation while letting through the maximum amount of visible light (380 to 780 nm) and a mini- mum amount of invisible heat (short infrared radiation: 780 to 2500 nm). This capability means that Thermobel Stopray is a ‘selective’ glazing.Thermobel Stopray’s selectivity can be seen in the diagram below (fig. 3), which shows: • incident solar radiation • solar radiation passing through a Thermobel Stopray Galaxy insulating glazing;Thermobel Stopray Galaxy lets through a considerable amount of light in the visible part of the spectrum (380-780 nm).On the other hand, it lets through virtually no solar heat in the form of short infrared radiation (780-2500 nm).Thermobel Stopray Galaxy is therefore «highly selective».

fig. 3 - Light transmissionfig. 2 - Solar Spectrum Thermobel Stopray Safir - AB Mercedes, Prague - CZECH REPUBLIC
wave length (nm)wave length (nm)