Some of these parameters correspond to those tabulated in the Pilkington publication Glass and Transmission Properties of Windows (7th edition), others correspond to EN410. These parameters are not used in Tas calculations and are displayed for information purposes only.
Transmittance
The fraction of visible radiation at normal incidence which is transmitted by the construction (same as the Tas derived parameter Light Transmittance).
Direct Transmittance
The fraction of solar radiation at normal incidence which is transmitted by the construction (same as the Tas derived parameter Solar Transmittance).
Reflectance
The fraction of external solar radiation at normal incidence which is reflected by the construction.
Absorptance
The fraction of external solar radiation at normal incidence which is absorbed by the construction.
Total Transmittance (G-value)
The fraction of solar radiation at normal incidence which is transferred through the construction by all means. It is composed of the Direct Transmittance and an appropriate fraction of the absorptance calculated for the assumed surface coefficients.
Short Wavelength
The Solar Direct Transmittance divided by 0.87.
Long Wavelength
The fraction of the Solar Absorptance that is released inwards, and contributes to the Solar Total Transmittance, divided by 0.87.
Total
The Solar Total Transmittance divided by 0.87.