Low-e glass is the abbreviation of Low Emissivity glass. Low-e glass is coated with a pure metallic silver film on the basis of an offline coating process to reduce the emissivity of the glass and improve the performance of the hollow. At the same time, the glass has good spectral selectivity and is based on a large amount of visible light. It can block a considerable part of infrared rays from entering the room, which not only keeps the indoor light bright, but also reduces the indoor heat load to a certain extent.
Two production methods of Low-E glass are:
1. Online high temperature pyrolysis deposition methodOnline high temperature pyrolysis deposition method. This method is completed during the float glass cooling process. Liquid metal or metal powder is sprayed directly onto the surface of the hot glass. As the glass cools, the metal film layer becomes a part of the glass. For this reason, the film is hard and durable. The "Low-E" glass produced by this method has many advantages: it can be bent and tempered, it does not have to be used in a hollow state, and it can be stored for a long time. Its disadvantage is its poor thermal performance. If you want to improve its thermal properties by increasing the film thickness, its transparency is very poor.
2. Offline vacuum sputtering method:
The "Low-E" glass produced by the sputtering method is different from the high-temperature pyrolytic deposition method. The sputtering method is offline. Sputtering process to produce Low-E glass requires a pure silver film as a functional film. The pure silver film is between the two metal oxide films. The metal oxide film provides protection to the pure silver film, and acts as an intermediate layer between the film layers to increase color purity and light transmittance.
Comparison of LOW-E glass and ordinary insulating glass
1. High-transmittance LOW-E glass
a) High visible light transmittance: natural lighting, transparent effect;
b) Higher solar transmittance, more solar heat radiation through glass;
c) Very high mid- and far-infrared reflectance: excellent heat insulation performance, low U value (heat transfer coefficient).
Scope of application: cold northern regions. In winter, solar thermal radiation enters the room through the glass to increase the indoor heat energy, while the far infrared emitted by indoor heating, home appliances, and human body is blocked and reflected back to the room, effectively reducing heating energy consumption;
2. Sun-shading LOW-E glass
a) Appropriate visible light transmittance, with a certain degree of shielding against strong outdoor light;
b) Low solar transmittance, effectively preventing solar heat radiation from entering the room;
c) The extremely high reflectivity of mid- and far-infrared rays restricts the secondary heat radiation from entering the room
Scope of application: suitable for southern and northern regions. This product not only restricts part of the solar heat energy from entering the room in winter, but also restricts more solar energy from entering the room in summer, because the intensity of solar energy in winter is only about 1/3 of that in summer, so the insulation performance is not affected. In terms of energy-saving effect, the sun-shading type is not lower than the high-transmitting type;
3. Double silver LOW-E glass
Product characteristics: Double-silver LOW-E glass, named for its double-layer silver layer in its film layer, is a more complex type of LOW-E glass film structure, and it is high-grade LOW-E glass. It highlights the shielding effect of glass on solar heat radiation, and cleverly combines the high light transmittance of glass with the low transmittance of solar heat radiation. Therefore, compared with ordinary LOW-E glass, the visible light transmittance is the same. Lower solar energy transmittance.
Scope of application: It is not restricted by region and is suitable for vast areas with different climate characteristics.
Maximum production size: 2540mmx4200mm
Comparison of online and offline Low-E glass
1. Production process
On-line Low-E glass is produced by spraying a chemical solution with tin salt as the main component on the hot glass surface during the production of float glass to form a single layer of tin oxide (SnO2) compound film with a certain low-radiation function Into.
Offline Low-E glass is made by uniformly plating metallic silver (Ag) and other metals and metal compounds with extremely low emissivity on the surface of the glass using vacuum magnetron sputtering on a special production line. It consists of at least four layers of film.
2. Variety and appearance
There is a single variety of online Low-E glass, which is restricted by the large-scale production of float glass. Currently, it is only 6mm thick, colorless and transparent.
There are various types of offline Low-E glass. According to different climate characteristics, high, medium and low transmittance products can be produced. The colors are silver gray, light gray, light blue and colorless and transparent. Colored glass can also be used to make green And many other colors. The thickness can be made from 3 to 12mm.