Te = Radiation Transmission Degree
The percentage of global radiation entering the room or office without changing wavelength. Global radiation is the combined Solar Radiation and general radiation from the sky.
T65 = Light Transmission Degree
The percentage of light passing through the glass and reflector. All daylight is not constant, we must assume a certain norm. D65 is the norm defined by DIN for European standards.
Tuv = Ultra Violet Transmission Degree
The percentage of ultra violet passing through. Measured between 280-380 nanometres. The UV transmission degree is of vital importance when we wish to protect objects from being damaged like colour coding.
re = Radiation Reflection Degree
This shows us the percentage of global radiation being reflected (ref. to Te).
r65 = Light Reflection Degree
Shows us the percentage of daylight being reflected (norm is D65).
q1 = Secondary Heat Radiation
Describes the percentage of energy entering the room by secondary effects (Convection-Re-Emission).
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gvalue = Total Energy Penetration Degree
This figure shows the TOTAL amount of energy coming into the room through the unit, it is therefore the only really important figure to consider for heating and cooling calculation. A figure of for example 16.2% means that an absolute total of 83.8% of all solar energy projected at the windows/units will be kept out nd will not enter the building through the uinits. The gvalue is calculated in combination with Te and q1.
Uvalue = Insulation Value
The Uvalue shows us the amount of energy passign through a unit, measured in Watts. It is explained in Watts per square metre x Kelvin (Uvalue = W(m2K)). Is is used for iindicating the amount of energy passing through a unit outwards from the building i.e. the insulation value.
Ra = Colour Reproduction Index Figure
Ra shows us how colours are reflected, with 100 being a true reflection.
4 Section have been defined under DIN 6169:
| Section 1:85-100 |
No distortion of the colour spectrum. |
| Section 2:70-84 |
Average distortion. |
| Section 3:40-69 |
Colours are badly reflected. |
| Section 4:00-39 |
Colours are difficult to distinguish. |
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