Scientific choice of energy-saving glass curtain wall glass

[China Glass Network] At present, building energy conservation has become a part of China's sustainable development strategy. The awareness of building energy conservation in the whole society is gradually strengthening. The advantages of glass curtain wall are better utilized, and the scientific and rational selection of glass has become the breakthrough energy consumption of glass curtain wall. Effective Ways.

Thermal insulation performance of glass curtain wall

The thermal insulation performance of the curtain wall is solved by controlling the total thermal resistance value and selecting the corresponding glass.

In order to reduce heat loss, it can be improved from three aspects. First, improve the thermal insulation performance of the lighting glass, try to use energy-saving vacuum glass, and reduce the number of opening windows. The second is to use a material with good heat insulation effect for the non-lighting part to lining the wall or to set the insulation core material. The third is sealing treatment and reducing air permeability. The hot summer and cold winter areas should be implemented according to the “Energy-saving Design Standards for Residential Buildings in Hot Summer and Cold Winter Zones”. In the design of curtain walls, appropriate energy-saving glass should be selected according to the energy-saving measures adopted in the area.

Colorful energy-saving glass
Glass is an important material that is difficult to replace in curtain walls and doors and windows. Although advances in glass technology offer many options, it is not easy to put the light-based glass into a curtain wall with multiple functional requirements. The contribution of glass to energy conservation cannot be ignored. The energy saving of glass is inseparable from the reflection, transmission, scattering and concentrating properties of glass itself. The application of light reflection, refraction, scattering and concentrating will play an important role in the uniform distribution of indoor light and avoiding sunlight glare and preventing heat radiation.

The endothermic glass heat absorbing glass can absorb or reflect a specific wavelength in the solar spectrum, and the heat absorbing glass is a body colored glass in which a coloring agent is added to the transparent glass. Although the heat resistance of the heat absorbing glass is better than that of the coated glass and the ordinary transparent glass, since the heat is radiated into the room during the secondary radiation process, the heat absorption and the light transmission are often contradictory, so the heat insulating function of the heat absorbing glass is Subject to certain restrictions. In particular, a significant portion of the heat absorbed by the heat absorbing glass still passes through the room. Therefore, the comprehensive energy saving effect when the heat absorbing glass is used as the curtain wall glass is not satisfactory.

The optical characteristic of heat-reflecting coated glass heat-reflecting coated glass is reflected heat radiation. Once the reflectivity and the projection rate are determined, the unidirectional characteristics are particularly prominent. That is, it can only meet some of the requirements of the changes in the built environment, such as the resistance to heat and heat absorption as the season changes. Moreover, the heat-reflecting properties of the heat-reflective coating and the heat-absorbing glass are at the expense of light transmission, and in most cases, it is not suitable for natural daylighting.

Low-E glass Low-E glass surface has low emissivity, high infrared reflectivity, low heat absorption, low temperature rise, low secondary radiant heat, and light transmittance of 33%~72% and shading coefficient of 1.25~0.68. Choose between. However, the heat radiation reflectivity of Low-E glass still has directional problems. The relevant data show that the test results of thermal conductivity in winter and summer are not the same whether the Low-E film surface is on the second or third side of the insulating glass. Big. The conclusion is that the effect of blocking the transmission of thermal radiation is independent of the season.

Insulating glass is a kind of two or more pieces of glass (called a glass substrate) for effective support. The surrounding area is sealed by glue. The air chamber is always filled with dry gas, which makes it energy-saving and heat-insulating. Products with three basic functions such as anti-condensation.

Foil glass Foil glass refers to a glass product with an organic film attached, which is broken under a sufficiently strong impact, and the glass age film can adhere to the organic film without scattering. The architectural glass organic film is made of a polyester film which is surface-metallized and then laminated with another polyester film. The surface is coated with a wear-resistant layer and the back surface is coated with a mounting adhesive, and a protective film is attached. Mounting it to the glass surface allows the glass to have enhanced glass safety (impact and support glass shards), or to have solar radiation control such as reduced solar heat and UV blocking.

The use of glass organic film with safety and energy saving performance is a feasible technical means to improve the safety of building glass and improve the energy-saving effect of buildings. The film glass can enhance the impact strength of the non-safety glass, prolong the time when the glass is broken by the external force, and prevent the body and property damage caused by splashing after the glass is broken.

The film glass made of transparent safety film does not increase the mechanical strength of the glass itself, but because the polyester layer of the film has very good impact resistance, when the film is strongly impacted by external force, the film will buffer a large amount of impact. And quickly decay, resulting in a difficult breakdown of the foil glass, thereby maintaining good film glass integrity.

The main functions of glass-added building energy-saving membranes are solar control, energy saving, safety explosion protection, glare blocking, UV blocking and glass surface protection. These membranes have certain safety performance and building energy-saving power with different requirements. Its performance indicators include visible light projection ratio, visible light reflectance, shading coefficient, U value and other indicators. Gel glass gel glass is a material filled between hollow glass, which is called "aerogel" material, which has a light transmittance of 45%, a transparent field of view comparable to that of hollow glass, and allows entry into the room. The light is evenly distributed. Good light transmission and high heat insulation are the main features of gel glass. The low-temperature radiation on the inside is much lower than that of ordinary insulating glass, so that the indoor temperature in winter can be guaranteed to be high. At the same time, it provides a great space for the refraction of light. The large transmission of light depends only on the incident angle of the sun to a small extent. Therefore, the natural light of daylight is always evenly distributed in the indoor space.

Scientific and rational selection of glass can effectively improve the energy-saving performance of glass curtain wall

The glass curtain wall with good energy-saving performance should adopt the double-layer or multi-layer insulating glass with optimized combination of photothermal effect, heat-dissipating composite metal sash, and open high-performance double sealing.

The heat resistance of the insulating glass is reflected in the fact that the internal gas is in a closed space, the gas does not convect, and the thermal conductivity of the air is almost zero. In order to improve the thermal insulation performance of the insulating glass, it is generally to increase the thickness of the space and to use an inert gas. These inert gases have stable properties, are inert and have low thermal conductivity, and replace the air inside the hollow glass with an inert gas, thereby reducing conduction. However, the space layer should not be too large. To reduce the radiation heat transfer, general coated glass or low-emission coated glass is used to control the transmission of various rays to reduce the radiation and heat transfer.

The energy-saving level of the glass curtain wall is also improved with the improvement of glass technology. It should be noted that a wide variety of functional glass has different energy saving effects. How to choose, according to the overall design requirements of the building and what parts to use, what kind of effect to achieve, to choose different types of energy-saving glass.

The technological upgrading of an industry is generally driven by the market demand for products. Technological advances driven by demand have both a clear direction and lasting momentum. In a market environment where building energy efficiency is widely recognized, all non-energy-saving building materials will be indifferent to the market, while energy-saving and environmentally-friendly building materials will suddenly emerge. Creating an energy-saving glass curtain wall is another breakthrough in improving glass technology. Improving energy-saving performance will promote new technological advances in deep-processed glass products.