Three directions of glass curtain wall development

2022-07-29
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Analysis: three directions of glass curtain wall development the development of glass curtain wall ecological technology is of great significance to the future construction industry In terms of constituent elements and modes, the development of glass curtain wall ecological technology includes three directions:

1 Construction technology

1.1 ventilation curtain wall

1.1.1 composition of ventilation curtain wall

ventilation curtain wall is composed of inner and outer glass curtain walls, or called double-layer curtain wall, breathable curtain wall, heat channel curtain wall, etc Compared with the traditional curtain wall, its biggest feature is that there is a ventilation layer between the two curtain walls. Due to the air circulation in the ventilation layer, the temperature of the inner curtain wall is close to the indoor temperature

1.1.2 principle of ventilation curtain wall Due to the function of the air exchange layer, it can save about 50% energy than the single-layer curtain wall; The outer glass of ventilated curtain wall can be colorless transparent glass or low reflection glass, which can also minimize the light pollution caused by glass reflection; The ventilated curtain wall has good sound insulation performance, which can maintain a quiet indoor environment; No matter the weather is good or bad, there is no need to open the window. The ventilation layer can directly transmit the natural air to the room, provide fresh air for the room, improve the indoor comfort and reduce the disadvantages brought by the air conditioning equipment

1.1.3 ventilation curtain wall

ventilation curtain wall can be divided into "closed internal circulation system" and "open external circulation system" according to different ventilation layer structures

in principle, the outer layer of the ventilated curtain wall of the closed internal circulation system is completely closed, which is composed of heat-insulating materials and insulating glass. The inner layer is generally a glass curtain wall or openable window composed of single-layer glass The ventilation layer between two curtain walls is 100mm-200mm The ventilation layer is connected with the ventilation system set at the ceiling, and the forced air circulation is carried out from bottom to top. The indoor air enters the ventilation layer through the vent at the lower part of the inner glass, so that the temperature of the inner curtain wall glass reaches or approaches the indoor temperature, so as to achieve the energy-saving effect

adjustable shutters or vertical blinds are set in the passage, which can effectively adjust the daylighting and shading, and create a more comfortable indoor environment

application examples of ventilation curtain wall of closed internal circulation system, such as Lloyd's headquarters building in the United Kingdom and western chemical center building in the United States

the outer layer of the ventilated curtain wall of the open external circulation system is a glass curtain wall composed of single-layer glass and non heat cut-off profiles, and the inner layer is a curtain wall composed of hollow glass and heat cut-off profiles Both ends of the ventilation layer formed by the inner and outer curtain walls are equipped with air inlet and exhaust devices, and sunshade devices can be set in the channel

in winter, close the air inlets and outlets at both ends of the ventilation layer, and the temperature of the air in the ventilation layer will rise under the sunlight, forming a greenhouse and reducing the heating cost of the building

open the air inlet and exhaust outlet of the air exchange layer in summer. Under the sunlight, the air temperature of the air exchange layer rises naturally, forming a bottom-up air flow, taking away the heat in the channel, reducing the temperature of the inner glass surface and reducing the refrigeration cost

through the control of air inlet and exhaust outlets and the structural design of inner curtain wall, fresh air can also be delivered from the ventilation layer to the room, so as to improve the air quality of the building, making it possible for high-rise buildings, especially super high-rise buildings, to naturally ventilate, and meeting the physical and psychological requirements of users to the greatest extent

buildings such as the commercial bank building in Frankfurt, Germany and the "RWE" headquarters building in Essen have adopted the open external circulation system ventilation curtain wall

due to the long heating time in cold areas, the "greenhouse effect" of the air exchange layer is mainly used to reduce the indoor heat loss when the ventilated curtain wall is selected The inner layer adopts hollow Low-E glass, heat insulation aluminum profile and relatively large width of air exchange layer to achieve better energy-saving effect In hot areas, the air conditioner has been used for a long time. The outer layer adopts heat reflective glass and a relatively small width of air exchange layer to enhance the effect of chimney effect and reduce the surface temperature of the inner layer glass, so as to achieve the best energy-saving effect

1.2 sunshade

the purpose of building sunshade is to block direct sunlight from entering the room through the glass, prevent excessive sunlight from irradiating and heating the building envelope, and prevent strong glare caused by direct sunlight Among the various energy-saving measures of glass curtain wall, sunshade technology may be the most potential and convenient construction means to save energy

good sun shading design is not only conducive to energy conservation, but also an organic component of curtain walls and an important element in shaping architectural aesthetics There are many kinds of sunshade components. For the side window, there are flat sunshade, horizontal sunshade, vertical sunshade, grid sunshade, etc For roof skylights and glass roofs, curtains and grids can give full play to the role of shading

in addition to the sun shading components, the use of natural factors such as greening and vegetation also has an ideal sun shading effect

horizontal sunshades are most widely used. The embassies of the five Nordic countries in Berlin have adopted horizontal sunshades. The green streamlined section sunshades are closely covered outside the windows and integrated with the whole wall

vertical shading can effectively block the light with very low height angle, which is suitable for East-West direction

the main facade and population of the Mexican Embassy in Berlin face east, and vertical shading can play the most effective role. The most prominent vertical shading component on the main facade is the vertical shading component that runs through the whole height from top to bottom These concrete sun visors can not only effectively block the sun, but also gradually increase the tilt angle, giving people a sense of rhythm How do you judge whether there is a problem with these equipment in the headquarters building of Palin Benz? This is very simple. The vertical yellow line of the vertical sun visor becomes a sign, creates a rich and colorful geometric shape, and becomes an integral part of the building

the dome of the German parliament building perfectly combines the sun shading on the top with natural ventilation. Not only can the soft diffuse light extend to the parliament hall on the bottom floor, but also the hot air in the hall can be discharged through the inverted cone surrounded by reflective panels, which can be described as killing two birds with one stone As the requirements for daylighting and sunshine vary in different seasons and times, it is necessary to adjust the shading effect of shading components

the atrium of the Potsdam energy center in Germany adopts adjustable curtain shading. With the change of time and the opening and closing of the curtain, the sunshine and Shadow form a unique environmental atmosphere In the air interlayer on another double-layer glass curtain wall of the building, a movable horizontal sunshade shutter curtain operated by remote control is installed. Users can adjust the angle of the shutter according to the intensity of the sun, effectively adjust and control the indoor light and reduce the heat absorption, and adapt to the weather in different seasons

for general sun shading components, manual adjustment is very effective, but for the glass curtain wall of large area and high-rise buildings, which accounts for 1/10 of the total output of plastic products in China, it needs to rely on automatic adjustment facilities Architects strive to apply modern automatic control technology to building shading, which not only meets the functional needs, but also creates a unique light and shadow effect

2 material technology

2.1 glass material

low radiation (compared with LOW-E) glass can reflect infrared rays in sunlight in summer, which can save air conditioning costs; In winter, the indoor heat can be reflected back to the room to reduce heat loss Low-E glass has been widely used at home and abroad

electrochromic glass is composed of glass, electrochromic medium, electrolyte, transparent electrode and other parts. The positive and negative electric fields are applied between the two surfaces of the glass, or the light transmittance is different when the electric field is applied and not applied, so that the indoor daylighting can be freely controlled

photochromic glass can automatically adjust the transmittance according to the intensity of sunlight. When the light is strong, the color darkens to reduce the transmittance, and when the light is weak, it completely restores the transparent state to achieve the maximum transmittance

people also print specific patterns on the glass surface through printing technology, which can not only ensure the privacy of the room after the glass is installed, but also block the strong sunlight like the sun shading device, and also express specific cultural meanings

2.2 heat break profile

heat break profile is an effective heat break layer formed by inserting a separator with low thermal conductivity between the inner and outer metal frames with high thermal conductivity to block the way of heat loss through the door and window frames or window sash profiles

heat break profile has reasonable structure, firm connection, high strength, good rigidity, large thermal resistance, and has excellent sound insulation, energy saving, wind resistance, air tightness and water tightness

heat break profiles were used in door frames in the early stage, mostly in flat open frames. Later, they were gradually used in framed glass curtain walls, but not in hidden framed glass curtain walls

3 control technology

people have also combined the ventilated curtain wall with the computer system to develop the intelligent curtain wall The energy consumption of buildings with intelligent curtain wall system is only 30% of that of traditional curtain wall

intelligent curtain wall is an extension of ventilated curtain wall, which can effectively regulate indoor air, temperature and light through computer system, and save energy consumption during building use Intelligent glass curtain wall includes glass curtain wall, ventilation system, air conditioning system, environmental monitoring system and building automatic control system

compared with traditional curtain wall and heat channel curtain wall, in addition to glass and supporting structure, some environmental control and building job system in the building are more important

4 outlook

with the arrival of the new century, people's requirements for comfortable working conditions are becoming more and more important In terms of lighting requirements, the wide application of computers raises the problem of how to avoid direct sunlight entering the room under the condition of ensuring natural lighting

with the prevalence of SARS, the closed and fully air-conditioned office conditions are increasingly criticized by users. Whether from the perspective of psychology or the special requirements of different users, the possibility of natural ventilation and the open conditions to nature have been widely welcomed by people

in addition, with the increasing awareness of environmental protection, the importance of light pollution and energy conservation has become a widespread consensus All this has become a new subject in front of modern glass curtain wall ecological technology

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