Glass is an important building material, and as the decorative requirements for buildings continue to increase, the use of glass in the construction industry is also increasing. However, when people choose the glass doors and windows of a building, in addition to considering its aesthetic and appearance characteristics, it pays more attention to the problems of heat control, cooling cost and comfortable balance of internal sunlight projection. This makes the new expensive in the coated glass family, Low-E glass, stand out and become the focus of attention.
Low-E glass, also known as low-emissivity glass, is a film-based product that is coated with multiple layers of metal or other compounds on the surface of the glass. The coating layer has high transmission of visible light and high reflection of mid-range infrared rays, and has excellent heat insulation effect and good light transmittance compared with ordinary glass and conventional architectural coated glass.
What are the magical effects of LOW-E glass installed on doors and windows? Let’s talk about it together:
LOW-E glass features
High infrared reflectivity, which can directly reflect far-infrared heat radiation.
The surface emissivity E is low, and the ability to absorb external energy is small, so that less heat is radiated.
The sunshade coefficient Sc is wide, and the amount of solar energy can be controlled as needed to meet the needs of different regions.
LOW-E film reflects heat characteristics
The LOW-E film is plated with a silver layer that reflects more than 98% of the far-infrared heat radiation, reflecting the heat directly as reflected by the mirror. The LOW-E shading coefficient Sc can be from 0.2 to 0.7, so that the direct solar radiant energy entering the room can be adjusted as needed.
LOW-E glass coating process
There are two main types: on-line coating, vacuum magnetron sputtering coating (also known as off-line coating). The in-line coated glass is manufactured on a float glass production line, which has a single variety, poor heat reflectivity, and low manufacturing cost. Its only advantage is that it can be hot bended. The off-line coated glass has a variety of varieties, excellent heat reflection performance and obvious energy-saving characteristics. The disadvantage is that it cannot be bent.
LOW-E glass use characteristics
The LOW-E glass manufactured by the vacuum magnetron sputtering process cannot be used in a single piece, and can only be used for synthesizing insulating glass or laminated glass. However, its emissivity E is much lower than 0.15 and can be as low as 0.01 or less. The LOW-E glass manufactured by the online coating process can be used in a single piece, but its emissivity is E=0.28. Strictly speaking, it cannot be called LOW-E glass (scientifically, the object with emissivity E≤0.15 is called low radiation). object).
The principle of LOW-E glass in summer and winter
In winter, the indoor temperature is higher than the outdoor, the far infrared heat radiation mainly comes from the indoor, and the LOW-E glass can reflect it back into the room to keep the heat in the room from diarrhea. For some solar radiation from the outside, LOW-E glass can still allow it to enter the room. This part of the energy is absorbed by the indoor object and then converted into far infrared heat radiation and left indoors.
In summer, the outdoor temperature is higher than indoors, and the far-infrared heat radiation mainly comes from the outside. Low-e glass can reflect it out to prevent heat from entering the room. For outdoor solar radiation, LOW-E glass with a low shading coefficient can be selected to restrict it from entering the room, thus reducing the cost (air conditioning cost).
Argon in LOW-E insulating glass
Argon gas is an inert gas, and its heat transfer property is inferior to that of air. Therefore, charging into the insulating glass can lower the U value of the insulating glass and increase the heat insulating property of the insulating glass. For LOW-E insulating glass, argon also acts to protect the LOW-E film layer.
Attenuated UV function of LOW-E glass
LOW-E glass reduces UV light by 25% compared to conventional single-piece clear glass. Compared to heat-reflective coated glass, LOW-E glass reduces UV light by 14%.