Energy-efficient architectural glass with low-emissivity coating to control solar heat gain
About half of the energy consumption of buildings comes from windows. lmproving the energy efficiency of window glass contributes a lot to the reduction of the electrical bill. The application of high-performance energy-efficient glass plays a key role in green building development and energy saving for society. As the leading energy-efficient glass manufacturer in China, CSG developed a brand new series of glass products with the latest coating technology, outstanding performance and a range of amazing colors, providing architects with exceptional options to meet the developing trend of architecture.
In the solar radiation, about 47% is visible light and 51% is infrared radiation (lR). The incoming solar lR through window glass causes heat accumulation and temperature rise, which is the major heat source of cooling load.
Comparison of different glass products with the same visible light transmittance:
Figure 1 shows transmission spectra of single silver Low-E, double silver Low-E and triple silver Low-E glass with the same visible light transmittance. Within the infrared region (780nm-2500nm), the area under the transmission curve reflects direct solar IR transmittance. The overall transmittance in the solar IR region is the sum of direct solar IR transmittance plus secondary transfer, defined as total solar IR transmittance(SIR), which quantitatively describes glass characteristics against solar IR. Much better than single and double silver Low-E glass as shown, all triple silver Low-E glass products of CSG have a direct solar IR transmittance below 2%, and a total solar IR transmittance around 3%, which indicates an extraordinary performance in reducing cooling load and creating a comfortable working and living environment in hot seasons.
Comparison of different glass products with the same shading coefficient
Shading coefficient (SC) is determined by integration over the whole solar spectrum from 300nm to 2500nm, which is often used to evaluate glass performance against solar heat in design practice and building codes. As a matter of fact, visible light acts differently from solar infrared radiation in the energy efficiency of buildings. Figure 2 shows a comparison of different glass products with the same SC. Obviously, triple silver glass has the lowest solar IR transmittance and in return the best performance against solar IR and in the reduction of cooling load. In view of all triple silver Low-E glass products having a direct solar IR transmittance below 2%, they should be better selected following visible light transmittance and aesthetic appearance requirements rather than shading coefficient SC to optimize energy efficiency of buildings.
The triple silver Low-E glass products have a wide range of visible light transmittance (from around 20% to 70%), different brightness (reflectivity from about 5% to 30%), and various colors (neutral, light grey, silver grey, silver, light blue, blue grey, etc.). Exhibiting a crystal clear look of satisfied colors at different viewing angles, the triple silver Low-E glass products are incredible combinations of best performance and outstanding aesthetic effect, providing architects with ideal options for various design concepts.
Ordinary low-E glass can’t be bent and post-tempered after coating, which limits larger-scale application of low-E glass and promotion of energy-efficient buildings.
In view of the prevailing conditions and economic development all over the world, CSG has researched and developed low-E coatings made of new materials which can be bent and post-tempered after coating to meet the need of curved low-E glass in current architectural design practice. The bendable low-E glass products have been widely used in a number of large buildings worldwide.
