As a symbol of modern architecture, glass curtain wall has been more and more widely used in China. It has lightweight, crystalline transmission and reflection properties, which can create a bright indoor light environment and achieve the effect of blending the interior and exterior spaces of the building, so it has become a new favorite for all kinds of building exterior façade design. However, in the process of use, people find that glass curtain walls also bring negative effects to us, such as light pollution and greenhouse effect.

Use energy-efficient glass for the building

Are glass curtain walls ecologically compliant? Do you take into account the details of energy saving? Has the use of space shading technology and glass curtain wall been considered? When the use of glass curtain wall and ecological energy saving is properly coordinated, this treatment of curtain wall can achieve the advantages of glass as a material. At present, there are three main types of energy-saving glass that are researched and promoted at home and abroad.

Insulating glass. The insulating glass is filled with krypton, argon or air, and its thermal conductivity is very low, and it has good thermal insulation performance. From the comprehensive consideration of performance and economy, the inner cavity of insulating glass is better to fill argon. There are two kinds of insulating glass commonly used in China, namely trough insulating glass and composite strip insulating glass. However, the current penetration rate of insulating glass in China is less than 1%. Insulating glass is an important way to achieve energy saving in glass curtain walls.

Vacuum glass. Glass materials have developed from monolithic glass and insulating glass to vacuum glass is the third generation of products. Vacuum glass is ordinary air or argon, and its sound insulation performance and light transmittance reduction coefficient are better than those of insulating glass.

Coated glass. Coated glass is usually coated with a metal film on the surface of the glass to change the transmittance and reflection coefficient of the glass, and it can be used in combination with insulating glass and vacuum glass. The coated low-emissivity glass developed in recent years has a high transmittance of 380~780nm visible light, which can ensure indoor visibility, and at the same time has a high reflectivity to infrared light, so as to achieve the effect of thermal insulation and energy saving.

Use of building greening methods

The introduction of eco-technologies is key to the use of glass curtain walls. The concept of "green technology" is to use modern technology to directly link the glass curtain wall with the vertical greening or horizontal three-dimensional greening of the building, and solve the problem of shading and ventilation with the help of embedded greening design, which can achieve multiple results.

Single-piece glass curtain wall greening. The initial practice was to plant green plants against the glass curtain wall, which obviously could basically achieve the purpose of shading and landscaping, and also had a certain thermal insulation effect, but the key was that the problem of natural ventilation was not solved.

Three-dimensional horizontal greening. The so-called three-dimensional horizontal greening refers to the implementation of a large area of greening between the different horizontal spacing of the glass curtain wall, such as building a sky garden outside the security layer of a high-rise building and leaving a vent, although the opening of the vent can not make the next room achieve the best ventilation effect, but can make the whole building produce air circulation and air exchange, and achieve a good effect as a whole.

Vertical curtain wall greening. The vertical curtain wall greening is to widen the vertical position between each glass block to become a green glass belt, which is divided into two layers, the outer layer is a dredged grid or louver-shaped synthetic organic matter, which can store a large amount of water, provide vertical plants (such as creepers, spider plants, etc.), and use the absorption and adsorption of water from plant roots to let plants grow between the steel frames of the curtain wall or between the glass blocks; The inner layer is a closable, openable shutter whose purpose is to avoid outside influences at the right time.

In short, compared with glass curtain walls, building greening can not only solve the problem of light pollution, but also solve the greenhouse effect. Specifically, it strengthens the convective heat transfer between the outer surface of the curtain wall and the surrounding air and the external environment, the heat transfer between the inner surface of the curtain wall and the indoor air and the indoor environment, the heat transfer between the curtain wall and the metal frame, and the radiation heat transfer reduced by the glass coating layer. The actual measurement data shows that the average diurnal temperature of the outer surface of the wall decreases from 35.1°C to 30.7°C in summer, a difference of 4.4°C, and the temperature of the inner surface of the wall decreases from 30.0°C to 29.1°C, a difference of 0.9°C. The cooling effect due to the evaporation of the foliage in the vicinity of the building also causes the wall to be slightly cooler than the air temperature (about 1.6°C). Obviously, the impact of greenery on the walls and indoor temperature is extremely important, and it also adds to the artistic beauty of the building.