Application of building energy-saving technology in ancient city protection?

What is the specific content of the application of building energy-saving technology in the protection of ancient cities? Here, Zhong Da Consulting will answer your questions.

1 background

As a worldwide trend, building energy conservation has been placed in a very important position by many countries. Developed countries in the world generally attach importance to building energy efficiency. For example, Germany has issued a series of policies and regulations on building energy efficiency, which stipulate the technical specifications of building insulation, ventilation, air conditioning and heating, and will be punished if it violates the relevant requirements [1]. Japan spends1.200 million dollars every year to publicize the awareness of environmental protection and energy conservation [2]. China is a big country in building energy consumption, and building energy conservation is a strategic measure for sustainable development. China is a big developing country, as well as a big building and cultural country. The National Climate Change Plan proposes that by 2020, China's carbon dioxide emissions per unit of GDP will be 40%~45% lower than that in 2005. The Strategic Action Plan for Energy Development (20 14-2020) also clearly stated that "by 2020, the total primary energy consumption will be controlled at about 4.8 billion tons of standard coal, the total coal consumption will be controlled at about 4.2 billion tons, and the proportion of non-fossil energy in primary energy consumption will reach 15%". 2014165438+1October 12. China and the United States reached an agreement to reduce greenhouse gas emissions and promised to stop increasing carbon dioxide emissions by 2030. It is imperative to popularize green and energy-saving buildings and promote sustainable development. General Secretary Jiang Zemin proposed that Yangzhou should be built into a famous city where ancient culture and modern civilization complement each other. Integrate ancient culture-ancient city protection with modern civilization-building energy conservation. This is a project planned by the government and a livelihood issue. Dongcheng District, Yangzhou is an old city that the municipal government focuses on reforming at present, and it is also an area where traditional houses are concentrated. According to the Measures for the Administration of Housing Planning and Construction in the Old Town of Yangzhou, the old town of Yangzhou covers Taizhou Road in the east, East-West Road in Nantong in the south, Erdaohe in the west and East-West Road in Yanfu in the north. Xiaoqinhuai River area is a unique old city in Yangzhou, and it is the only existing river in Yangzhou that can reflect the poetry of "small bridges and flowing water". It runs through the north and south of the ancient city, with many historical sites on both sides of the strait, profound cultural heritage and rich humanistic atmosphere. However, due to the long-term neglect of various factors and the lack of effective protection and reasonable development, the landscape on both sides of Xiaoqinghuai River has been eroded and destroyed.

2 Research content

Through investigation and analysis, the author organically combines the protection of the ancient city with the building energy-saving technology that reflects the advanced nature of the building and complements each other. First, sort out the cultural context of Yangzhou ancient city, and keep the original texture of traditional architecture more "green, ecological and energy-saving". Secondly, the Huaihe River area in Xiaoqing is selected as a pilot, and the data of building energy conservation are analyzed, and the conclusions and suggestions of building energy conservation suitable for this area are obtained, and the ideas of protection and energy conservation planning of Yangzhou ancient city are discussed from point to point. Third, ancient buildings are usually made of brick and wood, and their thermal conductivity is lower than that of reinforced concrete commonly used in modern buildings, so the energy-saving advantages of ancient buildings can not be ignored. This paper will discuss how to retain the energy-saving advantages of ancient building materials to the maximum extent without changing the structural types of ancient buildings, and apply them to modern buildings. Fourth, adopt modern energy-saving means, such as roof insulation and shading, energy-saving design of walls, doors, windows and floors, etc. Choose the architectural scheme suitable for the old city of Yangzhou to improve the living conditions of the residents in the old city.

3 building energy-saving data analysis

Based on the investigation of Xiaoqinhuai River in Yangzhou City, the author selected the most representative living conditions of more than 200 households for data analysis, and initially obtained the building energy-saving data of Yangzhou Old Town (Table 1). 3. 1 The per capita living area is small, and they are all buildings in the early days of liberation. The survey shows that the building area of each household in this area is 40~ 100m2, and most of them have three or even four generations living under one roof, and the per capita living area is less than 10m2. Only 20% of the buildings in this area have a history of more than 100 years, and most of them are buildings in the early days of liberation. Among them, buildings with high cultural value and long service life, such as the former site of Jiangdu County Cultural Salvation Association, the former site of Qi's Mountain Forest during the Republic of China, and Gujia Courtyard, are all repaired by Yangzhou Municipal People's Government, while other traditional buildings are repaired by residents themselves, so there are constantly repaired buildings in this area, but traditional buildings do not exist in isolation. Self-renovation is the destruction of architectural culture and architectural texture in this area. It is also an important task for the protection of the ancient city to make the architectural form chaotic and the traditional buildings need overall protection and transformation, and tailor the scheme according to their own characteristics to carry out reinforcement and energy-saving transformation. 3.2 The building energy efficiency is poor, and the building shape coefficient is large. Most buildings in this area have low energy-saving efficiency, and it is difficult to transform them. For example, roofs and walls need to be fully maintained, and insulation and waterproof layers should be set up. Only 9% of the residents in this area use independent toilets, and most of them do not have independent toilets and kitchens. The government can carry out renovation and maintenance, which can not only save costs, but also effectively improve the basic living conditions of residents. The shape coefficient is the ratio of the external surface area of a building in contact with outdoor air to the enclosed volume. Small complex buildings, bungalows and low-rise buildings have a large shape coefficient, which is not conducive to energy saving; Buildings with large volume and simple shape, as well as multi-storey and high-rise buildings, have small shape coefficient, which is conducive to energy saving. According to the survey, 53% of the buildings in this area have a shape coefficient greater than or equal to 0.3, which requires energy-saving renovation. The area ratio of window to wall of buildings in the old city is generally low, which not only affects the indoor natural lighting effect, but also increases the energy consumption of artificial light sources, so it is very important to enhance the lighting effect. 3.3 Characteristics of traditional building materials The building materials in this area are mainly solid clay bricks and wood, mostly brick-concrete and brick-wood structures. The energy-saving performance of building materials is superior to that of reinforced concrete and inferior to that of modern thermal insulation materials. The exterior wall decoration materials mainly include cement plastering and ceramic tiles. The biggest problem is that there is no insulation layer on the external wall, which causes great waste of indoor energy. Therefore, the energy-saving renovation of external walls is also very important. It is necessary to make an insulation layer on the inner side of the external wall, which is convenient for construction and can maintain the original style of the building. Most buildings in this area use wooden windows and steel security fences, and a small number of households have replaced aluminum alloy window frames. Due to the long service life, most of the wooden frames have rotted, and the energy saving effect is poor, which is in urgent need of improvement. Most houses don't use floors, and only those renovated or newly built in recent years use floors. 3.4 Roof characteristics of traditional buildings According to the survey data, 55% of buildings in this area have sloping roofs and 45% have flat roofs. Because the sloping roof has a good energy-saving effect and maintains the traditional architectural style, the "flat to sloping" project can be implemented. The roof is made of wood as the main load-bearing structural material, and the wooden beams are supported by wooden columns. Wooden purlins and rafters are erected on the beams, and roof tiles are laid on them. The maximum height from the roof to the ground is about 4m, and the minimum height is about 2.2m Because of its age, it is necessary to add tiles regularly to prevent leakage. There is no insulation on the roof in this area. It is understood that houses dissipate heat quickly in winter, so the roof can be renovated and heat insulation materials can be added. 3.5 Case study: No.9 Jiuxiang, an ancient building in the old city of Yangzhou, was built in the Qing Dynasty and took more than 900 working days. In the old days, it was about 22m wide from east to west and 25m long from north to south, with a total area of about 550m2. There are 25 old houses left today. The author measured the East House, which is about 7m wide from east to west, 4m long from north to south, 4m high and covers an area of 28m2. The building structure type is brick-concrete structure, and hollow brick wall is used for thermal insulation. Indoor window 1.2m wide, 1.5m high, canopy 1.5m long and 1.3m wide. The roof is a sloping roof, which can increase space and keep warm and insulate. The south window-wall ratio of this building is 0. 127, and there is no window in the north, and the shape coefficient is 1.29, so the building energy saving effect is poor.

4 Energy-saving transformation measures

Reconstruction is the destruction of building resources and the fault of historical context. Although most of the residential buildings in this area have a history of 60~ 100 years, they reflect the architectural features of China before and after liberation and play an irreplaceable role in Yangzhou's cultural heritage. Yangzhou has a history of 2500 years, and its architectural style is unique, profound and charming, which embodies the slow-paced lifestyle of people in the old city of Yangzhou. 4. 1 ground reconstruction due to the limitation of reconstruction, it is impossible to install a "geothermal exchange system", so it is necessary to lay an additional insulation layer on the ground (figure 1), which can reduce indoor heat loss. 4.2 Transformation of the inside of the external wall The external wall of traditional buildings is basically not insulated, and the walls and windows are easy to dissipate heat. Thermal insulation layer can be set on the outside and inside of the wall, and the thermal insulation material adopts EPS (polystyrene foam plastic) with good effect. The concrete methods are as follows: step one, waterproof and seal the building foundation; Step two, cleaning the inner substrate of the outer wall; Thirdly, covering the inner side of the big brick wall with a film, and installing insulation measures with plugs; Fourth, install glass fiber mesh and reinforced mortar; The fifth step is to use diatom mud, a green environmental protection material, to complete the interior wall (Figure 2). 4.3 Roof Reconstruction Due to the age, the roof has been seriously damaged, the materials of waterproof layer and thermal insulation layer have rotted, there is no thermal insulation function, and the heat loss is seriously wasted, which needs to be repaired. Adding insulation layer to the roof and daughter wall of the building can effectively isolate the sunlight at the top of the building [4]. The concrete methods are as follows: in the case of reasonable structure, the first step is to remove the roof tiles; Step two, laying a glass fiber net on the lower side of the roof brick; Step 3, install PU insulation layer with special screws; Fourthly, installing a water vapor separator as a waterproof sealing layer; Fifthly, installing a rafter template with wood; Step 6, install the roof tile (Figure 3). Doors and windows also need heat preservation. The window is reconstructed by double-layer vacuum glass, with thermal insulation door panels and wooden door and window frames installed on the outer surface, which not only retains the appearance characteristics of traditional buildings, but also effectively improves the thermal insulation efficiency. 4.4 Transformation of Solar Energy System 33% of the residents in this residential area have installed solar water heaters, with different brands and styles, all protruding from the roof, and the visual experience is rather messy. It is suggested that the flat solar collector can be used, and the flat plate is installed parallel to the roof and facing south, which is both energy-saving and beautiful. The roof and the solar collector are perfectly combined to form a unified beauty.

label

This scheme is a reconstruction project, and the shape, orientation, roof orientation and window orientation of the building cannot be changed. We can learn from Qionghuaguan Community Culture 19-2 zero-energy building in Guangling District of Yangzhou City, adopt the latest building energy-saving technology, change the easy-to-radiate parts of the building, such as external walls, roofs, doors and windows, and floors, and replace or increase the existing materials with relatively small thermal conductivity and easy construction. This paper selects the old city of Yangzhou as a pilot, analyzes the data of building energy conservation, draws conclusions and suggestions on building energy conservation suitable for this area, and discusses the ideas of protection and energy conservation planning of the old city of Yangzhou, taking the transformation of the old city as a demonstration, with a view to promoting the transformation of the old city of China.

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