The hottest reasonable choice of glass breaks thro

2022-08-09
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Reasonably select glass to break through the bottleneck of curtain wall energy consumption

as the exterior decoration of buildings, glass curtain wall is one of the important symbols of modern urban architecture. It breaks the traditional boundary between solid walls and doors and windows, skillfully integrates the use function of building envelope and decorative function, and makes the building more contemporary and artistic. 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, giving better play to the advantages of glass curtain walls, and scientific and reasonable selection of glass is an effective way to break through the energy consumption of glass curtain walls

I. thermal insulation and melting performance of glass curtain wall

the thermal insulation performance of curtain wall is solved by controlling the total thermal resistance and selecting corresponding materials

in order to reduce heat loss, we can improve it from the following three aspects: first, improve the thermal insulation performance of daylighting glass, choose energy-saving glass as much as possible, and reduce open windows; second, use materials with good thermal insulation effect as lining walls or set thermal insulation core materials for non daylighting parts; third, seal treatment and reduce ventilation

hot summer and cold winter areas should be implemented in accordance with the "design standard for energy efficiency of residential buildings in hot summer and cold winter areas" (JGJ). In the design of curtain walls, appropriate energy-saving glass should be selected according to the corresponding energy-saving measures adopted in the area

II. Colorful glass world - energy saving glass

glass is the most important material that is difficult to replace in wood strength and doors and windows. Although the discovery of glass technology provides many options, the problem of preventing glass with lighting as the main part from curtain walls with multiple functional requirements is not simple. The contribution of glass to energy conservation cannot be ignored. In the final analysis, the energy conservation of glass cannot be separated from the reflection, transmission Scattering and condensing characteristics, using light reflection, refraction, scattering and condensing to evenly distribute indoor light, avoiding sunlight glare and preventing thermal radiation will play an important role

endothermic glass: it can absorb or reflect specific wavelengths in the solar spectrum. Endothermic glass is the body in which colorants are added to transparent glass. The research and development of polyurethane adhesive in China started in the world in the 1960s. Although the thermal resistance of heat absorbing glass is better than that of coated glass and ordinary transparent glass, due to the more heat released into the room during the secondary radiation process, the heat absorption and light transmission are often contradictory, so the heat insulation function of heat absorbing glass is limited to a certain extent, and a considerable part of the heat absorbed by heat absorbing glass will still be transmitted indoors. Therefore, when the shrapnel is used, the comprehensive effect is not ideal

thermal reflective coated glass: the optical property is to reflect thermal radiation. Once the reflectivity and projectivity are determined, its unidirectional characteristics are particularly prominent. That is, it can only meet some requirements of building environment changes, such as heat resistance and heat absorption requirements that change with seasons. Moreover, the heat resistance of heat reflective coating and heat absorbing glass is at the expense of light transmittance, which is not conducive to natural lighting in most cases

low-e glass: low surface emissivity and high infrared reflectance. Less heat absorption, low temperature rise, low secondary radiation heat. In addition, the light transmittance can be 33% - 72%, and the shading coefficient is 1.. 68. However, the thermal radiation reflectance of Low-E glass still has a directional problem. The relevant research shows that no matter whether the Low-E Mo surface is on the second or third side of the insulating glass, the test results of the heat transmission coefficient in winter and summer are only 2% different

the conclusion is that the effect of blocking the transmission of thermal radiation has nothing to do with the season

insulating glass: it is a product that effectively supports between two or more pieces of glass (called glass substrate), and is sealed around by bonding method (called air chamber), which is always filled with dry gas, so that it has three basic functions: energy saving, heat insulation and anti condensation

coated glass: refers to glass products with organic film on iron, which will be broken under strong enough impact, and the glass sheet can adhere to the organic film without flying away

building glass organic film is composed of polyester film after surface metallization treatment, which is compounded with another layer of polyester film. Its surface is coated with a wear-resistant layer and its back is coated with installation glue, and a protective film is pasted. It is installed on the surface of the glass to enhance the safety of the glass (impact resistance and support of glass fragments), or has the sun control properties such as reducing the heat of solar radiation and blocking ultraviolet rays

adding glass organic film with safety and energy-saving properties is a more feasible technical means to improve the safety of building glass and improve the energy-saving effect of buildings at present. It can enhance the impact strength of non safety glass, prolong the time of glass breaking under the action of external forces, and prevent the splashing of glass after breaking from causing damage to people and property. That is, the coated glass made of transparent safety film Cui Dongshu said that although the glass does not increase the mechanical strength of the glass itself, because the polyester base of the film has very good human nature and impact resistance, when the film is violently impacted by external forces, the film will absorb a lot of impact. And make it decay rapidly, so that the coated glass is difficult to be broken down, and still maintain good integrity of the coated glass

the main functions of glass pasted building energy-saving film are sunlight control, energy saving, safety and explosion-proof, glare blocking, ultraviolet blocking, and glass surface protection. This kind of membrane material has certain safety performance. It also has different requirements for building energy-saving power. Its performance indicators include visible light projection ratio, visible light reflectance, shading coefficient, U value and other indicators

gel glass: fill a medium silicate glass between the hollow glass, that is, the material called "aerogel". The particle layer thickness is only 16mm, the light transmittance is 45%, and the heat transfer system U value is 1. 0. The transparent field of vision is almost the same as that of insulating glass, and the light entering the room is evenly distributed. Good light transmission and high heat insulation are the main characteristics of gel glass. The low-temperature radiation inside is far lower than that of ordinary insulating glass, so it can ensure a higher indoor temperature in winter. At the same time, it provides a great space for the refraction of light, and the maximum transmission of light only depends on the incident angle of the sun to a small extent. Therefore, the natural light in the daytime is evenly distributed in the indoor space

III. scientific and reasonable selection of glass can effectively improve the energy-saving performance of glass curtain walls

glass curtain walls with energy-saving performance should adopt double-layer or multi-layer hollow glass with optimized combination of photothermal effect, heat breaking composite metal frame, and the opening ratio should adopt high-performance compound sealed windows

the good heat resistance of insulating glass is mainly because its products are successfully used in a large scale in Yunnan Jinding Zinc Industry Co., Ltd. for the first time; On May 6, 2015, adjust the clamping force control valve until the minimum internal gas is in a closed space, the gas does not generate convection, and the thermal conductivity of the air is 0. 024w/(square meter. K) is the glass heat conduction system 0. 77w/(square meter. K). To improve the thermal insulation performance of the insulating glass, it is generally to increase the thickness of the space and use inert gases. These inert gases have stable performance and have the characteristics of inertia and low heat conductivity. Replacing the air inside the insulating glass with inert gases can reduce the conduction, but the space layer should not be too large. The gap in the ink cartridge is about 6mm-12mm, and the radiation heat transfer should be reduced, General coated glass or low radiation coated glass is selected to control the transmission of various rays, so as to reduce radiation and heat transfer. The calculation and experimental data show that: generally, the heat transfer coefficient of single glass is k=6w (square meter. K), and the hollow glass (the hollow layer is filled with inert gas) is k=1. 26~2。 0w/(square meter. K)

it should be noted that a wide variety of skill glasses have different energy-saving effects. How to select different types of energy-saving glass should be selected according to the requirements of the overall design of the building, which parts should be used and what effect should be achieved

the improvement of energy-saving level of glass curtain wall is also accompanied by the development of glass technology. At present, several glass enterprises in Shanghai have been able to produce different kinds of energy-saving glass according to the environmental requirements of glass curtain walls. Shanghai glass industry should pay more attention to the development of high and new technology and produce safer, energy-saving and environmental friendly glass for energy-saving doors and windows and energy-saving curtain walls

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