1.Vacuum laminated glass
Products can be made into a single sandwich structure, can also be made of double-sided sandwich structure, EVA film (also known as EN film) thickness of about 0.4 and 0.7mm two. The thickness of the polycarbonate plate is about 1.2 mm. Additional glass plates are used between 2.5mm and 5mm. Toughened glass can also be used. Another method of vacuum laminated glass is to pour glue in the middle of two layers of glass, and then it can also be vacuum laminated glass by heating and drying. It is characterized by safety and security, and its heat transfer coefficient, sound insulation and The wind pressure resistance and other properties are also superior to the original vacuum glass sheets, and the total thickness is also relatively thin. Because the thermal conductivity of the glass and the laminated layer is relatively small, it contributes less to the thermal resistance. Therefore, the heat transfer coefficient of the vacuum laminated glass is only slightly smaller than that of the vacuum glass, but the sound insulation performance will be greatly improved.
2. "vacuum + hollow" combination vacuum glass
This structure is equivalent to the vacuum glass as a glass and then combined with additional glass plate hollow, additional glass plate thickness is generally selected 5 or 6mm tempered glass, placed on the outside of the building, can also be made of "hollow + vacuum + hollow" Double-sided hollow combination.
In addition to the safety features of this type of combination, its thermal insulation performance has also been improved. In particular, additional glass plates are also used
Low-E tempered glass also reduces the heat transfer coefficient.
To calculate this kind of composite glass, we must first realize from the principle that in the range of temperature and temperature difference we are discussing, the wavelength of thermal radiation is in the far-infrared 4-40 μm band, and soda-lime-silica glass is basically opaque to electromagnetic radiation in this band. Therefore, when calculating the radiant thermal resistance of three or more glasses, it is not necessary to consider the effect of the radiation passing through the first block on the third block, as long as the calculations are repeated and then added, so if the total heat of the "vacuum + hollow" combination The resistance is R combination and can be written as: R combination = R + R hollow
Where R is the thermal resistance of vacuum glass
R-hollow is the thermal resistance of two hollow glass made of equal glass with additional glass plate thickness
The calculated R combination only calculates the thermal resistance of one glass, and the error is small.
3. "Vacuum sandwich + hollow" structure
The heat transfer coefficient of this structure is similar to the above-mentioned "vacuum + hollow", but the advantage of this structure is that in addition to the low heat transfer coefficient and the safety is solved, the thickness is thinner than "hollow + vacuum + hollow" and due to both sides of the vacuum glass Asymmetry reduces the resonance of sound propagation and improves sound insulation performance.
A sample was made for a music teaching building in Beijing, which was a 6+0.38EVA+4L+0.15V+4+12A+6 structure with a total thickness of 32.5mm. The sound insulation measured by the Building Physics Laboratory of Tsinghua University was 42dB. The national standard of glass curtain walls is only 3dB worse than the highest level of sound insulation. The heat transfer coefficient can be between 0.7-0.9Wm-2k-1, determined by the selection of LOW-E glass.
4. Double vacuum layer vacuum glass
The total thermal resistance of this kind of structure can be regarded as the sum of the thermal resistances of two pieces of vacuum glass. If it is the same structure of vacuum glass, the total thermal resistance is twice that of single vacuum glass, ie, R double vacuum = 2R
Where R is the thermal resistance of a single vacuum glass
It should be noted that the position of the Low-E film in the structure is different, does not affect the K value, and only affects the temperature distribution of the three glass sheets in actual use.
Double vacuum glass has high thermal resistance, low K value, and is thin, can be made about 9mm thick, and can also be made into double vacuum laminated glass, which has very good development potential.