Glass is the most important material in wood walls and doors and windows, which can hardly be replaced. Although the discovery of glass technology provides many choices, the glass mainly used for lighting is placed in the curtain wall with multiple functional requirements. The problem is not simple. Glass is energy efficient. This contribution cannot be ignored. The energy saving of glass can not be separated from its reflection, transmission, scattering and focusing characteristics. Although the discovery of glass technology provides many choices, the use of light and anti glass is the most important material in wooden walls and doors and windows, which can hardly be replaced. However, the glass mainly used for lighting is placed in curtain walls with multiple functional requirements. The problem is not simple. The contribution of glass to energy conservation cannot be ignored. The energy saving of glass is inseparable from the reflection and transmission of glass itself. Scattering, light collection characteristics and the use of light reflection, refraction, scattering and spotlights to evenly distribute indoor light to avoid solar glare and prevent thermal radiation will play a major role.
Heat absorbing glass: Absorbs or reflects a specific wavelength in the solar spectrum. Heat absorbing glass is a kind of colored glass, in which colorants are added. Although the heat resistance of the heat absorbing glass is better than that of the coated glass and ordinary transparent glass, the heat absorption function and light transmission are often contradictory due to the heat released to the room in the process of secondary radiation, so the heat insulation function of the heat absorbing glass is limited, and most of the heat absorbed by the heat absorbing glass will still be transferred to the interior. Therefore, when using shrapnel, the overall effect is not ideal.
Thermal reflective coated glass: the optical property is reflective thermal radiation. Once the reflectivity and projection are determined, the unidirectional characteristic is particularly prominent. In other words, it can only meet part of the changes in the building environment, such as the requirements of heat resistance and heat absorption with seasonal changes. In addition, the heat resistance of the heat reflective coating and the heat absorbing glass is at the expense of light transmission, and is not conducive to natural lighting in most cases.
LOW-E glass: low surface emissivity and high infrared reflectivity. Less heat absorption, less heat generation, and low secondary radiant heat. In addition, the light transmittance can be 33% - 72%, and the shading coefficient is selected between 1.25 and 0.8. However, the directivity of the thermal radiation reflectivity of LOW-E glass still exists. The experiment shows that whether the LOW-E Mo surface is on the second side or the third side of the insulating glass, the test results of thermal conductivity are all in winter and summer. Only 2% difference. The conclusion is that the effect of blocking heat radiation transmission is independent of seasons.
Hollow glass: it is an effective support between two or more glasses (referred to as glass substrate), which is sealed around with glue, and (referred to as air chamber) is always filled with dry gas, so that it has three basic functions: energy conservation, heat insulation, anti condensation, etc.
Foil glass: refers to the glass product with organic film made of iron, which is broken under strong enough impact, and the glass aging film can adhere to the organic film without scattering. The architectural glass organic film is composed of a polyester film with metallized surface and laminated with another layer of polyester film. The surface of the organic film is coated with a wear-resistant layer, the back is coated with installation glue, and the glass surface is coated with a protective film. Provides enhanced glass safety (impact resistance and supporting glass fragments), or solar control performance that reduces solar radiation heat and blocks ultraviolet rays.
The use of glass and organic film with safety and energy saving properties is a feasible technical means to improve the safety of building glass and improve the effect of building energy conservation. It can improve the impact strength of non safety glass and extend the external force of glass. Breaking time can prevent property loss caused by glass splash. That is, the film made of transparent safety film will not increase the mechanical strength of the glass itself, but because the polyester base film of the film has very good humanity and impact resistance, when the film is subjected to the violent impact of external forces, the film will absorb. Great impact. It is quickly attenuated, which makes it difficult to decompose the film glass and still maintains good integrity of the film glass. The main functions of glass laminated building energy-saving membrane are solar energy control, energy conservation, safety and explosion-proof, anti glare, anti ultraviolet and protection of glass surface. The film has certain safety properties. The requirements for building energy-saving power are still different. Its performance indicators include visible light projection ratio, visible light reflectivity, shadow coefficient, U value and other indicators.
Gel glass: a hollow silicate glass filled with a medium silicate glass called aerogel, whose particle layer thickness is only 16 mm, light transmittance is 45%, and the U value of the heat transfer system is 1.0. The transparent vision is almost the same as that of the insulating glass, so that the light entering the room is evenly distributed. Light transmission and high insulation are the main characteristics of gel glass. The low temperature radiation inside is far lower than that of ordinary insulating glass, so it is possible to ensure higher indoor temperature in winter. At the same time, it provides a large space for light refraction. The maximum transmission of light depends only to a small extent on the angle of incidence of the sun. Therefore, the natural light of sunlight is evenly distributed in the indoor space.
December 26, 2022
