Shading coefficient of U-shaped glass
As the name implies, it is the ability of glass to block or resist solar energy. In English, Shading Coefficient is abbreviated as Sc. In my country's GB/T2680, it is called the shading coefficient, abbreviated as Se. The ratio of solar radiation to transparent flat glass.
The smaller the shading coefficient, the better the performance of blocking sunlight and heat from projecting indoors. As the requirements for energy saving in buildings are getting higher and higher, in terms of architectural glass, the most important thing is the shading (shading) coefficient Sc (or Se) and the heat transfer coefficient K value (or U value).
The shading coefficient of ordinary glass is relatively high, ?s is about 0.9, so it is necessary to carry out surface coating processing on the glass, such as heat-reflecting glass, low-emissivity glass, etc. It is possible to reduce the shading system, so I won't describe it here.
There are several concepts to note about the shading coefficient: the shading coefficient not only includes sunlight (300nm-2500nm spectrum penetrates the glass into the room, but also includes the energy of the secondary heat transfer of the glass. For example, the direct sunlight transmittance of a piece of brown glass is 50 %, while the total sunlight transmittance is 63%, so the extra 13% is the secondary radiation absorbed by the glass.
Second, the shading coefficient of a certain glass is 0.5. It cannot be considered that the glass can allow 50% of the sun’s heat to enter the room. It should be understood that the sun’s heat that the glass can transmit is 50% of the heat transmitted by the standard 3mm white glass.
The third is about the heading ratio. We call the value of the solar transmittance of the standard 3mm white glass the heading ratio. The value in my country is 0.889, while the international one is 0.87. It seems that this difference is not very big, but when compared with There should be consensus when foreign construction projects are involved. Example Calculation of shading coefficient Sc = solar heat gain coefficient (SHGC) / heading ratio. When the SHGC is 0.818, the national fuel frequency {value is 0.92, while the foreign calculation? {result is 0.94.
It is also necessary to understand the solar heat gain coefficient SHGC: (also known as the total solar transmittance, heat gain factor, g value). It means that under the same conditions, the solar radiation energy enters the room through the glass. The opening of the same size but no glass enters the room. The ratio of solar energy and heat has this solution? We can understand The shading factor is defined.
