At present, single-layer aluminum alloy windows are mostly used in high-rise building windows. There are many ways to solve high-efficiency thermal insulation and energy-saving windows, such as increasing the number of glass layers.
If double-layer glass is used, one layer has thermal insulation coating on the inner side, and its thermal insulation effect is approximately equivalent to three-layer glass; if the polyester film with thermal insulation coating is stretched on the frame and placed between two layers of glass, its heat transfer Coefficient K=1.25W (㎡K).
The transmittance of the solar spectrum and visible light of the thermal insulation coating is high, but the reflectivity is low, but the opposite is true for infrared rays with wavelengths > 2Sum. In addition, the emissivity E value of this coating is low, which can reduce the radiation heat exchange with the indoor environment, which is more favorable for thermal insulation.
In the heat dissipation of the envelope structure, about 50% to 60% of the heat is lost through the door and window structure, so it should be paid attention to in the energy-saving renovation of high-rise buildings.
The energy-saving design of external door and window system mainly includes thermal insulation performance and air tightness design.
The energy-saving design of the external door and window system needs to be controlled from the air tightness of the door and window, the area of the window wall, and the material of the door and window according to the local conditions, so as to improve the indoor thermal comfort and reduce the building energy consumption.