Application and control research of energy-saving technology for building curtain wall doors and windows.

For building curtain wall doors and windows, it is an important component of the construction maintenance structure. While improving the overall aesthetics of the building, it also has the characteristics of strong heat exchange and heat conduction. Therefore, the heat generated by building curtain wall doors and windows, the loss is often relatively large, and it belongs to the content that needs to be considered when carrying out energy saving and consumption reduction work in buildings. To improve the energy-saving level of buildings, it is necessary to conduct in-depth research on the application and control of energy-saving technologies for building curtain walls, doors, and windows, to promote the continuous development of glass construction and building industry.

1. The overview of building curtain wall

A building curtain wall is a kind of external wall enclosure structure of a building. In the actual construction process, this structure is not load-bearing and can be effectively hung up like a curtain, so it is named "The glass curtain wall". It belongs to various large and high-rise buildings at the present stage. A light wall with good decoration is commonly used in engineering projects. Most of the building curtain wall is composed of panels and a supporting structure system. Compared with the main structure, it has a good ability to move or deform. Its advantages are listed in Table 1.

Table 1 Overview of Main Advantages of Building Curtain Walls

2. Main factors affecting the energy-saving effect of building curtain walls, doors, and windows

2.1 Airtightness

The airtightness of curtain wall doors and windows mainly refers to the barrier ability of curtain wall doors and windows to airflow after splicing, which can have a direct impact on building heat loss. In the actual construction process, if the splicing work of curtain wall doors and windows is not carried out reasonably by relevant standards and requirements, it is easy to have relatively large splicing gaps. The gaps flow through, and then the problem of heat loss occurs, which is a key way for the heat loss of buildings. Therefore, when carrying out the splicing work of curtain walls, doors, and windows, it is necessary to do a good job in air-tightness experiments to ensure that the gaps are reduced as much as possible, to ensure that the indoor heat will not be lost due to the existence of gaps.

2.2 Thermal conductivity

From the current point of view, indoor heat can be transferred under the effective effect of conductivity, so that the indoor temperature drops or rises. Often, the greater the thermal conductivity coefficient, the greater the actual heat loss, and the better the building insulation effect will be. Difference. For building curtain walls, doors, and windows, they have a certain degree of thermal conductivity, so their materials can have a greater impact on the thermal conductivity of buildings. For example, at this stage, most of the curtain wall doors and windows are made of glass. If the quality of the glass is relatively good, or the application form of the glass is more reasonable, it will reduce heat loss. For example, hollow glass has better heat preservation and energy saving effect than ordinary glass.

3. Application research on energy-saving technology of building curtain wall doors and windows

3.1 Thermal break technology

Heat insulation technology generally refers to cutting off the effective transfer of heat between two parts. The application of this technology in building curtain wall doors and windows mainly uses some heat insulation materials to achieve the heat between the inside and outside of the building. for efficient isolation purposes. In practical applications, there are generally two types of materials that are widely used at this stage, namely aluminum alloy materials and galvanized materials. These two materials have good thermal insulation effects and can be designed in different shapes and colors to the aesthetic requirements of curtain wall doors and windows. In addition, compared with traditional materials, these two materials have good fire resistance, and the materials are cheap, which can reduce construction costs.

3.2 High-performance sealing technology

Since the airtightness of curtain wall doors and windows can have a direct impact on the energy-saving effect of buildings, it is necessary to give enough attention to sealing technology when carrying out curtain wall doors and window construction. In recent years, sealing technology has developed relatively rapidly, and the sealing effect that can be obtained is getting better and better, but there are still some deficiencies in terms of air penetration and heat exchange in buildings. Most of the technical means at the present stage are to effectively fill some special materials in the corresponding gaps between buildings and curtain walls, doors, and windows, to achieve the purpose of transmitting air or heat. Combined with the actual application of curtain wall door and window technology at the present stage, there is a close relationship between energy saving and the sealing effect. Often the sealing technology is good enough to ensure the energy-saving effect of the building. For high-performance sealing technology, it is to achieve the purpose of enhancing building thermal insulation and heat insulation by improving the independence of indoor and outdoor airflow, and relatively good sealing quality can also play a certain role in building sound insulation. enhancement. Therefore, at this stage, high-performance sealing technology has been paid attention to by the construction industry and has begun to be widely used.

3.3 Glass Technology

For building curtain wall doors and windows, glass is the most common construction material, and it is also a key content to achieving building energy conservation. At this stage, the more common energy-saving glass generally includes the following types.

Solar reflective glass. 

This kind of glass has a very high application rate in building curtain wall doors and windows. Because the coating of this glass can reflect light well, it can effectively reflect far-infrared light. As far as far-infrared light is concerned, it can promote the continuous increase of the overall temperature of the building. Through effective reflection, it can ensure that the building has good heat insulation performance, thereby improving the comfort of the house. It can be said that in hot summer, this kind of glass can reduce the use of indoor air conditioners to a certain extent, thereby achieving the purpose of energy saving and environmental protection.

Low-E glass.

For low-emissivity glass (as shown in Figure 1), it can also be called Low-E glass, which refers to a corresponding film product that is effectively coated with multiple layers of metal or some other compounds on the surface of the glass, which can It has good energy-saving and thermal insulation functions, and it is also a relatively common energy-saving glass at this stage. Under normal circumstances, this kind of glass can not only transmit light normally, but also ensure that the building gets effective light, and at the same time, it can effectively block part of the heat energy. That is to say, part of the heat energy generated by the sun or HVAC can be effectively reflected the original space by this glass, and will not be smoothly transmitted through the glass. Therefore, this kind of glass can insulate heat in summer and heat in winter, which can achieve a good energy-saving effect.

^{Figure 1 The low-emissivity glass}

Insulating glass.

Insulating glass mainly refers to the two-layer or multi-layer flat glass. With the help of high-strength and high-air-tight corresponding composite adhesives, the glass sheet and the corresponding interior with a desiccant are effectively bonded. The aluminum alloy frame is bonded to produce high-performance soundproof and thermally insulating glass. At this stage, this kind of glass is widely used in construction projects, and it can be said to be the best choice for curtain wall doors and windows to achieve energy-saving and thermal insulation effects. To improve the energy-saving effect of curtain wall doors and windows, in the actual design of double-layer insulating glass, for the outermost layer of glass, the designer can set it as a sunshade, heat absorption, and heat reflection glass, and for the innermost layer of glass, it can be Choose low-emissivity glass. This can not only ensure the aesthetics of the building but also greatly improve the energy-saving and thermal insulation performance of curtain walls, doors, and windows.

3.4 Hardware equipment

For curtain wall doors and windows, hardware accessories are inseparable from the installation process. At this stage, most of the widely used hardware accessories are multi-locking hardware accessories, which can cooperate with curtain wall doors and windows to improve their air tightness and thermal insulation to a large extent, to promote the overall building to obtain a relatively good energy-saving effect.

3.5 Reasonable design of doors and windows

First of all, control the design ratio of doors and windows. The design ratio of doors and windows can have a direct impact on the thermal performance of the building. Second, the door and window style design. The style of doors and windows, can not only affect the overall aesthetics of the building but also affect the energy-saving effect of the building.

Secondly, the opening form design of doors and windows. Combined with practical experience, fixed windows, and casement windows often have better energy-saving effects than sliding windows. At the same time, sliding windows generally use sliding tracks to achieve the purpose of opening. During this operation, it is easier and faster to form hot and cold air. Convection, which leads to relatively large energy losses in the building,

4 Research on energy-saving control measures of building curtain wall doors and windows

4.1 Do a good job in the control of the orientation of doors and windows of the curtain wall and the ratio of windows to walls

When carrying out the design work of building curtain walls, doors, and windows, designers should fully consider the nature of the building, its specific functions, and the climate and environmental conditions of the area where the building is located. At the same time, it is necessary to reasonably and effectively control the window-to-wall ratio. The window-to-wall ratio usually needs to be controlled at around 0.3. For the north, the lighting is the worst, especially in winter, it is almost impossible to absorb heat, so it is rarely used in the design at the present stage. Reasonable selection, if there is no requirement, it is recommended to face south, to achieve the best energy-saving effect.

4.2 Do a good job in the design of sunshade facilities

For the curtain wall doors and windows at the present stage, in the actual application process, they can only play a certain role in energy saving and heat preservation, and some auxiliary sunshade facilities are needed to effectively reduce the actual sunshine area of the curtain wall doors and windows glass, to a certain extent. Reduce the frequency of use of air conditioners, fans, etc., and then achieve the purpose of saving power. The more common shading methods at this stage mainly include horizontal shading, vertical shading, grid-type shading, baffle-type shading, etc., which need to be combined with the specific type of construction project, the actual location, the specific orientation, and the specific purpose. Carry out reasonable and effective selection work. In addition, the sunshade measures that are widely used in curtain wall doors and windows at this stage are generally internal and external roller blinds and shutters.

4.3 Do a good job of heat preservation

Because the heat in buildings in some cold regions is easy to lose, and the loss of this heat can further increase the heating burden of the building, so for the curtain walls, doors, and windows of buildings in cold regions, attention should be paid to the insulation work to prevent heat loss as much as possible. For example, designers can effectively add thermal insulation materials to frame materials, which can greatly improve the thermal insulation effect of curtain wall doors and windows, thereby achieving the purpose of saving energy and reducing consumption.

4.4 Rationally use curtain wall energy-saving technology

First of all, increase the use of photoelectric curtain walls. The photovoltaic curtain wall mainly uses photovoltaic cells to collect and utilize solar energy. The basic principle is to arrange a series of corresponding photovoltaic cells in parallel reasonably and Resin is used to effectively bond the battery pack and glass to form a photovoltaic panel. The back of the photoelectric panel needs to be properly connected to the junction box with wires, so that light energy can be effectively converted into electrical energy for utilization, and a good energy-saving effect can be achieved.

Second, the double-layer curtain wall. The double-layer curtain wall, the composition can be roughly divided into inner and outer two-layer curtain walls, shading system, and ventilation equipment. It can use ventilation equipment to achieve the purpose of air buffering between the inner and outer curtain walls. At the same time, it can be combined with the sunshade system to form a relatively complete high-quality building with good thermal insulation functions, ventilation functions, and sound insulation and noise reduction functions. Energy-saving and environmentally friendly building curtain walls.

5. Conclusion

In recent years, with the continuous enhancement of people's awareness of environmental protection, higher and higher requirements have been put forward for the energy-saving and environmental protection performance of various buildings. Building curtain wall doors and windows can play an important role in improving the overall energy-saving effect of the building. Therefore, designers should pay attention to combining various factors and rationally select corresponding energy-saving technologies and energy-saving control measures to improve the energy-saving level of building curtain wall doors and windows, thereby promoting The construction industry will achieve healthy and long-term development.

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