China's building energy consumption is two to three times that of developed countries in the same climatic conditions. In the process of building a well-off society in an all-round way, the task of energy conservation and emission reduction is very arduous. Building energy conservation is the basis for improving residential comfort and reducing the cost of use. It is also an urgent requirement for sustainable development. Only by putting resources and reducing energy consumption in a prominent position can we promote the construction of a harmonious society.
65% of building energy efficiency is mainly borne by the building envelope system. In the outer protective structure, the glass curtain wall, which is a major feature of modern architecture, was widely used in China's construction projects in the 1990s, but there are also many problems, such as improper glass selection, so that the solar energy through the glass in summer is other materials. Several times the wall; the selected sealant has poor bonding effect, the glue joint construction is not in place, the rubber strip is not tightly sealed, the structure is deformed to produce cracks, and the cold and hot air permeation is serious; the profiles, thermal insulation materials, and filling are used. The material is unreasonable, the node is not correct, and the spacers are not effectively disposed between the components, so that the amount of heat loss in the room is large; together with the light pollution generated by the glass reflecting light, the structure is not strong and becomes a "time bomb" in the air.
Due to the consideration of construction costs, some construction units and design units use materials and construct ordinary glass curtain walls. In order to maximize the energy saving of this kind of glass curtain wall project, it is required that all participants of the project must carefully design according to the Technical Specifications for Glass Curtain Wall Engineering (JGJ102-2003) and relevant technical standards and energy conservation regulations. Careful construction, strict management, and good energy conservation.
I. Design
It is necessary to fully consider the thermal insulation, heat insulation and sealing performance of the glass curtain wall project, and select materials with sufficient strength and rigidity to prevent the glass curtain wall from being deformed under the load of typhoon, earthquake and self-weight to cause cracks.
2. Material selection
Palladium-plated glass should be used as much as possible because its enamel layer can effectively block solar energy from radiating into the room. For example, when using single-plate chrome-plated glass, products produced by in-line thermal spray method should be used (the film layer is firm and durable). The thickness of the glass is related to the structural safety, and also affects the transmission of thermal energy. When the frame is used to support the curtain wall, the thickness of the single piece of glass should not be less than 6 mm, and the thickness of the single piece of laminated glass should not be less than 5 mm.
Insulation materials play an important role in energy conservation and also enhance fire protection. Curtain wall engineering should use rock wool, mineral wool, glass wool, etc. as thermal insulation materials, which has the advantages of good thermal insulation performance, thermal conductivity of only 0. 044 W / (m · K), the highest operating temperature of 650 ° C.
The structural bonding between the glass and the aluminum sub-frame must use a neutral silicone structural sealant. The structural adhesive has stable performance (use temperature is -48-88 ° C, heat resistance is 150 ° C, cold deformation is not obvious), Strong adhesion. However, when the glass curtain wall and the point-supporting curtain wall are coated glass, the acid silicone sealant should not be bonded (the metal element contained in the coating layer reacts with the acid gel will cause the bond to break).
Weatherproof sealants should be made of silicone construction sealant. Silicone sealant has good UV resistance, so it is durable, not suitable for aging and cracking, and has good compatibility with silicone structural adhesive, glass and other components, and has good bonding effect.
A polyethylene foam rod having a density of not more than 0. 037 g/?3 is used as a filling material between the glass and the glass wall of the profiled groove, and the material has light weight and good heat preservation performance.
The gap around the glass curtain wall opening window, the glass of the exposed frame curtain wall and the gap of the profile should be sealed with EPDM rubber, neoprene rubber or silicone rubber. Among them, silicone rubber (good weather resistance and small permanent deformation) has the best quality. This point is easily overlooked in the curtain wall project, and the rubber strip is considered to be of little effect. In fact, if the rubber strip is aged, it will cause serious problems such as water leakage and air permeability, which will affect the thermal insulation effect of the curtain wall.
Third, the use of materials
Use heat-reflecting LOW-E glass, insulating glass, etc. These glasses have been produced in China for a long time, but they are expensive. Therefore, they have been used less frequently in glass curtain wall projects. For example, insulating glass composed of heat-reflecting glass and transparent glass is better than brick-and-brick brick walls. Use aluminum-plastic composite materials and heat-insulating profiles for the beams and columns of the curtain wall. When using insulated aluminum profiles, such as the use of the strip process, the insulation material should use PUR materials. In addition, the existing curtain wall glass film can also effectively reduce energy consumption. Now the insulation safety film on the market can save more than 15%.
Fourth, the structural aspects
The use of visor, grille, sun visor and other shading facilities can minimize direct sunlight and avoid overheating in the room, thus achieving better insulation and energy saving. Sunshade louvers have horizontal louvers and vertical louvers, split-control, electric and adjustable louver systems. According to the architectural style and needs, different forms and control methods can be used.
The ventilated curtain wall consisting of two inner and outer glass curtain walls is also called double-layer curtain wall, breathing curtain wall and hot channel curtain wall. A ventilation and ventilation layer is formed between the inner and outer curtain walls. Due to the circulation or circulation of air in the ventilation layer, the temperature of the inner curtain wall is close to the indoor temperature and the temperature difference is reduced, which saves energy compared with the traditional curtain wall heating. %-52%, saving energy by 38%-60% during cooling.
The intelligent curtain wall is an extension of the ventilated curtain wall. It is based on the intelligent building. The building supporting technology (warm, heat, light, electricity) is moderately controlled. The indoor air, temperature and light are effectively adjusted by the computer, and the building energy consumption is only equivalent. 30% of the traditional curtain wall.
The basic unit of the photoelectric curtain wall is a photoelectric plate. The photoelectric plate is a battery array which is composed of a plurality of photovoltaic cells in series and parallel. The battery array is placed in two layers of glass (the upper layer is transparent glass, and the lower layer is arbitrary). The resin is thermoset, and the junction box and wires are placed on the back of the photovoltaic panel, so that solar energy can be converted into electrical energy for use. In general, the columns and beams of such curtain walls are made of insulated aluminum profiles.
In summary, engineering and technical personnel should improve their own business quality, familiar with the technical points of the glass curtain wall project, carry out the work meticulously, and strictly control the energy saving of the curtain wall project. Government departments should increase the management of energy conservation in glass curtain wall projects. The construction unit should strengthen the concept of energy conservation, and also ensure the structural safety of the glass curtain wall project and reduce light pollution, so that the glass curtain wall project can be both beautiful and practical.
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