1 one Vacuum laminated glass
The product can be made into a single-sided sandwich structure or a double-sided sandwich structure. The thickness of the EVA film (also known as EN film) is approximately 0.4 and 0.7mm. The thickness of the polycarbonate sheet is approximately 1.2mm. The additional glass plate is selected between 2.5mm and 5mm, and tempered glass can also be used. There is another way to make vacuum laminated glass, which is to pour glue between two layers of glass and then dry it by heating. Vacuum laminated glass can also be made. Its characteristics are safety and anti-theft. At the same time, its heat transfer coefficient, sound insulation and wind pressure resistance are also superior to the original vacuum glass sheet, and the total thickness is relatively thin. Due to the relatively high thermal conductivity of glass and the laminated layer, their contribution to thermal resistance is relatively small. Therefore, the heat transfer coefficient of vacuum laminated glass is only slightly smaller than that of vacuum glass, but its sound insulation performance will be significantly improved.
2 "Vacuum + insulating" combined vacuum glass
This structure is equivalent to treating vacuum glass as a piece of glass and then combining it with an additional glass plate to form a hollow layer. The thickness of the additional glass plate is generally selected as 5 or 6mm tempered glass and placed on the outside of the building. It can also be made into a double-sided hollow combination form of "hollow + vacuum + hollow".
In addition to addressing safety issues, such combinations also enhance their heat insulation and sound insulation performance. Especially when the additional glass plate also selects Low-E tempered glass, the heat transfer coefficient is further reduced.
When calculating this kind of combined glass, it is first necessary to recognize in principle that within the temperature and temperature difference range we are discussing, the wavelength of thermal radiation is in the far-infrared band of 4-40μm. Soda-calcium glass is basically opaque to electromagnetic radiation in this band. Therefore, when calculating the radiant thermal resistance of more than three pieces of glass, there is no need to consider the influence of the radiation passing through the first piece on the third piece. Just calculate in segments and then add them together. Therefore, if the total thermal resistance of the "vacuum + hollow" combination is R combination, it can be written as: R combination =R+R hollow
In the formula, R is the thermal resistance of vacuum glass
The thermal resistance of R insulating glass is made of two pieces of glass of the same thickness as the additional glass plate
The calculated R combination only calculates the thermal resistance of one more piece of glass, with a very small error.
3 "Vacuum interlayer + hollow" structure
The heat transfer coefficient of this structure is similar to that of the aforementioned "vacuum + hollow" structure. However, in addition to having a low heat transfer coefficient and ensuring safety, the advantages of this structure include a thinner thickness than "hollow + vacuum + hollow", and due to the asymmetry on both sides of the vacuum glass, the resonance of sound transmission is reduced, thereby enhancing the sound insulation performance.
A sample was once made for a music teaching building in Beijing. It was of a structure of 6+0.38EVA+4L+0.15V+4+12A+6, with a total thickness of 32.5mm. The weighted sound insulation measured by the Building Physics Laboratory of Tsinghua University was 42dB, which was only 3dB short of the highest weighted sound insulation standard for glass curtain walls in the country. The heat transfer coefficient can be between 0.7-0.9Wm-2k-1, which is determined by the selection of LOW-E glass.
4. Double vacuum layer vacuum glass
The total thermal resistance of this structure can be regarded as the sum of the thermal resistances of two vacuum glasses. If the vacuum glasses of the same structure are used, the total thermal resistance is twice that of a single vacuum glass, that is, R double vacuum =2R
In the formula, R represents the thermal resistance of a single vacuum glass
It should be noted that the different positions of the Low-E film in the structure do not affect the K value but only the temperature distribution of the three pieces of glass during actual use.
Double vacuum glass has a high thermal resistance, a low K value, and is very thin, capable of being approximately 9mm thick. It can also be made into double vacuum layer laminated safety glass and has great development potential.
