Three directions of ecological technology developm

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Three directions for the development of ecological technology of doors, windows and glass curtain walls

sustainable development is an important concept in the contemporary world, and green building has attracted more and more attention Although the thermal performance of glass curtain wall is greatly improved compared with ordinary windows, it is still a weak link in building energy consumption The development of glass curtain wall ecological technology is of great significance

in terms of constituent elements and modes, the development of glass curtain wall ecological technology includes three directions:

1) construction technology; 2) Material technology; 3) Control technology

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 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 circulation of air 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

ventilation curtain wall adopts the principle of chimney effect to solve the problem of energy saving from the function Due to the function of the air exchange layer, it saves 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 air conditioning equipment

1.1.3 ventilation curtain

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

in principle, the outer layer of the ventilated curtain wall of the closed internal circulation system is completely closed, which is composed of heat breaking profiles and insulating glass. Its inner layer is generally a glass curtain wall or openable window composed of single-layer glass One of the two curtain walls makes you feel more comfortable working. The ventilation layer in the room is 100mm-200mm The ventilation layer is connected with the ventilation system set at the ceiling, and forced air circulation is carried out from bottom to top. 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 is close to the indoor temperature, so as to achieve energy-saving effect

adjustable shutters or vertical blinds are set in the channel, which can effectively adjust the lighting and shading, and create a more comfortable environment indoors

application examples of ventilated curtain walls with closed internal circulation system, such as Lloyd's headquarters building in Britain 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 insulating profiles, and the inner layer is a curtain wall composed of hollow glass and heat insulating 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 rises 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 and floats upward, 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 the air inlet and exhaust outlets and the structural design of the inner curtain wall, fresh air can also be delivered from the ventilation layer to the interior, improving the air quality of the building, making it possible for the natural ventilation of high-rise buildings, especially super high-rise buildings, 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 ventilated curtain walls with open external circulation system

protect the passenger area in the car in cold weather. Due to the long heating time, when using ventilated curtain wall, the "greenhouse effect" of the ventilation layer is mainly used to reduce the indoor heat loss The inner layer adopts hollow Low-E glass, heat breaking aluminum profile and relatively large ventilation layer width to achieve better energy-saving effect In hot areas, the use time of air conditioning refrigeration is long. The outer layer adopts heat reflective glass and relatively small width of air exchange layer to enhance the effect of chimney effect and reduce the temperature of the inner glass surface, so as to achieve the best energy-saving effect

1.2 sunshade device

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 direct sunlight from causing strong glare Among various energy-saving measures of glass curtain wall, sunshade technology may be the most potential and convenient construction means to save energy

good sunshade 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 sunshade components, the use of natural factors such as greening and vegetation also has a fairly ideal sunshade effect

horizontal sunshade is the most widely used. The embassies of the five Nordic countries in Berlin have adopted horizontal sunshades. The green streamline section sunshade is closely covered outside the window and integrated with the whole wall

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

the main facade and population of the Mexican Embassy in Berlin face east, and the vertical shading can play the most effective role. The most prominent component on the main facade is the vertical shading component that runs through the whole height from top to bottom These concrete sunshades can not only effectively block the sun, but also gradually increase the tilt angle, giving people a sense of rhythm The vertical yellow line of the vertical sunshade of the headquarters building of Palin Benz company has become a sign, creating a rich and colorful geometric shape and becoming an integral part of the building

the dome of the German parliament building perfectly combines the 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 of 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 sunlight, effectively adjust and control indoor light and reduce heat absorption, and adapt to different seasons

for general sun shading components, manual adjustment is very effective, but for glass curtain walls of large areas and high-rise buildings, 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 indoors to reduce heat loss Low radiation (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 lighting can be freely controlled

photochromic glass can automatically adjust the transmittance according to the intensity of sunlight, darken the color when the light is strong, reduce the transmittance, and completely restore the transparent state when the light is weak, reaching the maximum transmittance

people also print specific patterns on the surface of the glass 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 The heat breaking profile has reasonable structure, firm connection, high strength, good rigidity and large thermal resistance, and has excellent sound insulation, energy saving, wind resistance, air tightness and water tightness In the early stage, heat breaking profiles were used for door frames, mostly for flat open frames, and later gradually used for framed glass curtain walls, not for hidden frame glass curtain walls

3 control technology 1 generally speaking

people have also combined ventilated curtain walls with electronic computer systems to develop intelligent curtain walls 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 adjust indoor air, temperature and light through computer system, so as to save energy consumption during the use of buildings 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 walls and heat channel curtain walls, in addition to glass and supporting structures, part of the environmental control and building job system in the building are more important

compared with stainless steel and titanium products, the key to significantly reduce the weight of intelligent curtain wall lies in the intelligent control system, which is the whole process control system from functional requirements to control mode, from information collection to the execution of command transmission mechanism. It involves the measurement of climate, temperature, humidity, air freshness, illumination, the collection and control of operating state information of heating, ventilation, air conditioning and sunshade, as well as the configuration and control of power system, Building computer control and other factors are a set of more complex system engineering

4 outlook

with the arrival of the new century, people's requirements for comfortable working conditions have become more and more important In terms of lighting requirements, the wide application of computers raises the problem of how to avoid sunlight entering the room directly 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 continuous strengthening of environmental awareness, the importance of light pollution and energy conservation has become a widespread consensus All this has become a new topic in front of modern glass curtain wall ecological technology

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