Be alert to the energy saving effect of building houses around glass

Of the four enclosure components that affect building energy consumption, doors and windows, walls, roofs and ground, the thermal insulation performance of doors and windows is the worst, which is one of the major factors affecting the indoor thermal environment quality and building energy conservation. As for the typical enclosures in China, the energy consumption of doors and windows accounts for about 40%-50% of the total energy consumption of building enclosures. According to statistics, in the case of heating or air conditioning, the heat loss from single glass windows in winter is about Occupying 30%-50% of the heating load, the amount of cooling consumed by the solar radiant heat transmitted through the single glass window in the summer accounts for approximately 20%-30% of the air-conditioning load. The heat loss of windows of buildings outside China is Canada and In other northern hemisphere countries, more than twice the number of buildings of the same kind, improving the thermal insulation performance of doors and windows, and reducing the energy consumption of doors and windows, is an important part of improving indoor thermal environment quality and improving building energy efficiency.

Residential buildings are characterized by a large number of irregularities on the facades and complex body shapes. At present, residential buildings increase the lighting area or use large-opening windows and doors for daylighting and appearance, and the ratio of window to wall area increases, which is not conducive to building energy conservation. The energy efficiency standards of residential buildings comprehensively consider the building shape coefficient and window wall area ratio. Based on the analysis of energy consumption in cold regions and climate subregions of cold regions and considering the current maturity of energy-saving technologies, the limits of heat transfer coefficients of enclosure structures are determined.

In order to adapt buildings to different climatic conditions and meet energy saving requirements, the thermal performance requirements of building envelope structures are more reasonable. This standard uses cold days and cold regions based on the number of days of heating capacity, HDD18, and the number of days of air conditioning, CCD26, as indicators of climate zones. Divided into five different climatic communities. According to the building climate zone, the reasonable thermal performance parameters of the building envelope are determined, and the limits of the heat transfer coefficient of the building envelope and the limit value of the external window glass shading coefficient are proposed respectively.

In severe cold and cold regions, the loss of heat from indoor and outdoor heat transfer during the heating period dominates. Therefore, the heat transfer coefficient of the window (including the transparent part of the balcony door) is required to be high. The impact of the window on the energy consumption of the building mainly includes two aspects. One is that the heat transfer coefficient of the window affects the heating in winter and the indoor and outdoor temperature difference during summer air conditioning; the other is that the window is affected by solar radiation to cause indoor heat gain. In winter, the solar radiation that enters the room through the window is conducive to building energy efficiency. Therefore, reducing the heat transfer coefficient of the window to suppress temperature difference heat transfer is one of the main ways to reduce window heat loss; in summer, the solar radiant heat that enters the room through the window becomes Air conditioning cooling load, therefore, to reduce the solar radiation into the room and reduce the temperature difference between the window or transparent curtain wall heat transfer is a way to reduce air conditioning energy consumption.

In the process of energy saving and development of windows and doors, the glass used in the curtain walls of windows and doors, followed by float glass, heat absorbing glass, heat reflecting glass, Low-E glass with its unique optical characteristics, good thermal insulation properties and non-reflective light pollution Environmental performance has become the fastest growing energy-saving glass in recent years. Over the past few years, Low-E glass production has increased significantly under the promotion of national building energy conservation policies. According to incomplete statistics, by the end of 2007, there were more than 20 online and offline Low-E glass production lines with a certain scale and quality level in China. In 2007, the market sales volume reached 151-1700 million square meters, and some enterprises’ products had a good situation that supply was in short supply. . With the formulation and implementation of energy-saving design standards for residential buildings in cold and cold areas, the use of Low-E glass in residential buildings will be further promoted. Energy-saving work for residential buildings will inevitably contribute to the development of Low-E glass and other energy-saving glass. A broader space for development.