Put an end to non insulating glass and advocate gr

Put an end to non insulating glass and advocate green environmental protection

in order to implement the national policy of saving energy, effectively protecting the environment, reducing greenhouse gas emissions, and further realizing energy conservation and emission reduction, and according to the actual conditions in Beijing, improve energy utilization and reduce building energy consumption, the Beijing Municipal Planning Commission, based on the Beijing "design standard for energy efficiency of public buildings" db11/, The new design standard for energy efficiency of public buildings (hereinafter referred to as the new standard) was revised and formulated

since May 20, the new version of the standard has been publicly solicited for comments, which requires that elevators in newly-built, expanded and reconstructed public buildings should have the function of no-load shutdown. At the same time, they should also compete with foreign experimental machines. Insulating glass should be used for glass curtain walls, and the room direction design should reduce the energy consumption caused by four-season changes

it is predicted that by 2015, the total urban building area in Beijing will reach 840million square meters, of which the public building area will be 320million square meters, and the building energy consumption will account for 33.6% of the total energy consumption of the whole society. Among them, the growth trend of energy consumption of large public buildings is prominent. Therefore, it is very necessary to further improve the energy-saving design standards of public buildings and reduce the energy consumption of large public buildings from the source

"Beijing's 12th Five Year Plan for energy efficiency in civil buildings" (hereinafter referred to as the "plan") points out that during the "12th Five Year Plan", Beijing will further improve the functions of the capital and international metropolises, accelerate the development of high-end industries, and accelerate the urbanization process in the suburbs in accordance with the goal of building a world city. The plan also clearly requires that the design standard for energy efficiency of public buildings be revised before 2015

in order to meet the needs of building energy conservation during the "12th Five Year Plan" period, Beijing has revised and completed the design standard for energy efficiency of residential buildings for the fourth stage of energy conservation in 2012, and now it has prepared the design standard for energy efficiency of public buildings with higher energy conservation goals

restrict the use of non insulating glass

the new version of the standard stipulates in the form of mandatory provisions that in buildings dominated by glass curtain walls, only less than 15% of the lighting area can be used. At present, the company focuses on the field of light-weight utilization of non insulating glass in vehicles. "Due to the functional requirements, the ground floor entrance lobby of class A and class B public buildings often adopts the glass ribbed all glass transparent curtain wall, which cannot use hollow glass, and its heat transfer coefficient often does not meet the limit requirements for the transparent part of the enclosure. In order to ensure the thermal performance of the enclosure, it is necessary to put forward control requirements for the area of non hollow glass, and the area of non hollow glass in tall space should not exceed the same height." 15% of the total area of the light transmission part of the surface (excluding the outer door). "

in order to ensure that the average heat transfer coefficient of all light transmission parts of the facade meets the requirements, other hollow glass computers can read out the first data block and then carry out operations such as calculation, display and drawing, ensuring the uninterrupted distribution of all data. The heat transfer coefficient of the points should be less than the limit, so as to make up for the deficiency of hollow glass. The average heat transfer coefficient is calculated by weighting the area of each light transmission part of the same facade, and the formula is as follows: kpj= ∑ (Ki · FI)/fz. Where: KPJ is the average heat transfer coefficient [w/(M2 · K)] calculated by the weighted area of each light transmission part of the same facade; Ki is the heat transfer coefficient of each light transmission part of the same facade (excluding the outer door) [w/(M2 · K)]; Fi refers to the area of each light transmission part of the same facade (excluding the outer door) (M2); FZ refers to the total area of each light transmission part of the same facade (excluding the outer door) (M2)

limit the area of the light transmission part

in the provisions on "architectural design", the new version of the standard requires that the ratio MD of the area of the light transmission part of the roof to the total area of the roof should not be greater than 0.20. When the class a building does not meet the requirements, the thermal performance trade-off judgment of the enclosure structure should be carried out

window wall area ratio ml is not only an important factor affecting building energy consumption, but also restricted by indoor environmental requirements such as building sunshine, daylighting, natural ventilation and so on. Generally, the heat insulation performance of the transparent part of the enclosure and the outer door is much worse than that of the non transparent outer wall. The larger the ML is, the greater the energy consumption of heating and air conditioning is. Therefore, from the perspective of reducing building energy consumption, ML value must be limited

due to the diversity of public building forms and the needs of building functions, many public buildings have atriums, hoping to have a transparent public space with good microclimate and artificial ecological environment in the inner area of the building. However, judging from the projects that have been completed so far, the thermal environment of a large number of atriums is not ideal and energy consumption is high. The main reason is that the thermal performance of transparent materials in atriums is poor compared with that of non transparent roofs, and the heat transfer loss and solar radiation gain are too large. Therefore, the new version of the standard also limits the area of the light transmission part of the roof

for those buildings in class a buildings that increase the light transmission area of the facade and roof due to the needs of vision and lighting effects, if the designed building can not meet the specified index requirements of ML and MD and breaks through the limit value, the building must be weighed and judged according to the relevant regulations

when the window wall area ratio ml of single facade of class A and class B buildings is ≥ 0.40, considering improving the natural lighting conditions of the room to save lighting energy consumption, it is stipulated that the visible light transmittance of glass (or other light transmitting materials) should not be less than 0.4; When the window wall area is relatively small and ml is less than 0.40, the visible light transmittance of the light transmitting material should not be less than 0.60

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