1. Connotation and definition of green building
The connotation of 1. 1
Green building is a method to realize the concept of sustainable development in the process of urban construction, which needs clear design concept, specific technical support and operable evaluation system. In different institutions and different angles, the concept of green building has different emphases.
The American Green Building Association has formulated an operable green building assessment system (LEED), which holds that the pursuit of green building is how to realize the whole life cycle of building materials from production, transportation, construction, construction to operation and demolition, with minimal harm to the environment and comfortable quality of life for users and residents.
Wikipedia describes green building as a practical activity, aiming at improving the utilization efficiency of buildings in terms of land, energy, water and materials, and reducing the negative impact of buildings on people's health and surrounding environment through more detailed and comprehensive consideration at all stages of the whole life cycle.
In view of the relative shortage of resources in China, China has put forward the goal of energy-saving and land-saving residential buildings and public buildings as green buildings to solve the problems of excessive resource consumption and increasing shortage in the rapid development of industrialization and urbanization in China. This is a concept of sustainable architecture with China characteristics, which realizes the sustainable development of architecture by saving energy, land, water and materials.
1.2 definition
On the premise of conforming to the objective laws of natural ecosystem and living in harmony with natural ecosystem, a sustainable, renewable and recyclable whole-life building with minimum resource consumption, maximum efficiency, safe, healthy and livable functions and minimal disturbance to the ecosystem is a green building.
Green building is not a certain kind of building. Through the analysis of green culture, philosophy and ideas, we know that green building is not only a way of life, but also an idea. It does not necessarily refer to any kind of building, but covers all types of buildings, including residence, production, life and public activities. From a single green building, its green connotation is a series, including culture, ecology and environmental protection.
2. Green building design principles
After decades of practice, green buildings have gradually formed some important design ideas, principles and methods. Green building design is essentially an architectural development view dominated by ecological ethics and ecological aesthetics. Green building design should follow the following principles in practice:
2. 1. The principle of harmony
As an influence of human behavior, architecture has results. Because of its practical function of consumption, disturbance and influence in the process of space selection, construction and life cycle of use and demolition, its system harmony, system harmony and relationship harmony have become important harmony principles that green buildings particularly emphasize.
2.2. The principle of applicability
Any regional planning, urban construction or single building project must be based on the analysis and evaluation of local specific conditions, including regional climate characteristics, geographical factors, local cultural customs, building mechanism characteristics, various energy distribution conducive to environmental sustainability, such as the utilization intensity and durability of local building materials, and various local restrictions.
2.3 Economic principles
Pay attention to the principle of saving energy and land. Land conservation should start from the planning stage, rationally allocate the proportion of land for production, living, greening, landscape and transportation, and improve the land utilization rate. The technical principle of energy saving is to reduce energy consumption, improve energy utilization efficiency and make full use of renewable natural resources, including solar energy, wind energy, water conservancy energy, ocean energy and biological energy. To reduce the use of non-renewable resources. In architectural design, according to different climatic characteristics, according to the operation law of the sun and the formation law of the wind, energy-saving measures such as sunshine and ventilation are adopted to reduce energy consumption.
2.4. Comfort principle
Comfort requirements, resource occupation and energy consumption have always been a pair of contradictions in building construction, use and maintenance management. The emphasis on the principle of comfort in green buildings is not based on sacrificing the comfort of buildings, but on meeting the comfort requirements of human habitation. The thermal storage and insulation performance of materials are applied to improve the thermal insulation performance of the maintenance structure, and solar energy is used to warm in winter and cool in summer, and sunshade facilities are used to prevent overheating in summer, thus ultimately improving the comfort of the indoor environment.
2.5 Economic principles
The construction, use and maintenance of green buildings is a complex technical system problem and also a social organization system problem. Although the extremely green building with high investment and high technology can reflect the high-end level of human science and technology development, it is not only high technology that can realize the function, efficiency and quality of green building. Appropriate technology is also the road to the development of green buildings with localized materials and regional characteristics.
3. Key points of green building design
At first, the design of green building was misunderstood as only the greening and beautification design of a building area. Now everyone agrees with the multi-system design. After more than ten years, the cognitive level of builders, designers and users has been improved, and building materials, building technology and supporting products have also changed with each passing day.
Building energy-saving design has long been included in the scope of construction drawing review, and numerous mandatory codes have been able to ensure that buildings meet the national energy-saving standards. Our designers should not only be satisfied with the minimum standards of specifications, but should pay more attention to cutting-edge scientific and technological information, master new materials and technologies, and make bold attempts and innovations in green design.
The design process of green building involves many specialties, especially planning, architecture, water supply and drainage, electricity, heating and ventilation, which is a whole system design. In this system, when the planning and site selection are determined, the architectural specialty plays a decisive role in the success or failure of green building design. Through study and work practice, I personally think that in the process of architectural design, there are the following links that need to be focused and controlled.
3. 1. Water system
In order to save water, green buildings need to improve the utilization rate of water resources, that is, reuse wastewater and rainwater, improve the water environment system from the original supply and drainage mode, increase the necessary storage and treatment facilities, and form a recycling mode of water resources for supply, drainage, storage and reuse.
Residential building planning needs to consider tap water, sewage and rainwater, and may also include the introduction, transportation, discharge and treatment of direct drinking water, municipal reclaimed water, groundwater and surface water. The collection, utilization and discharge of rainwater are closely related to green building planning. For example, the floor space of roofs, green spaces and roads in building areas and their surface paving materials directly affect the runoff and infiltration of rainwater. If the purpose of increasing rainwater infiltration is to choose paving materials such as roads and squares with good water permeability, improve the matrix of green space and increase its water storage capacity. Roof greening will also store some rainfall and reduce the runoff of roof rainwater, and the runoff coefficient can be reduced from 0.9 to about 0.3.
Sewage and rainwater are generally transported by gravity as much as possible, so the design of sewage pipeline needs to cooperate with the elevation design of the site. Green space has the functions of accumulating rainwater, increasing rainwater infiltration and intercepting rainwater pollutants. Therefore, the terrain of green space in green buildings should be designed to be lower than roads, squares and so on. , so as to better play the function and comprehensive benefits of green space.
The sewage and rainwater pipelines outside the building should be unified with the site road planning, so as to facilitate the pipeline excavation and future maintenance. The water quality of rainwater runoff from roads and parking lots is poor, so it is necessary to consider appropriate pollution interception measures when collecting rainwater, such as low-potential green space and ecological retention system.
3.2 Wind environment
Creating a good ventilation and convection environment and establishing a natural air circulation system are important manifestations of green design principles. Here, the design of optimizing natural ventilation is often ignored by us. Especially in residential quarters, in order to obtain higher economic benefits, developers often pursue higher building density and floor area ratio, and the building spacing can only meet the minimum sunshine spacing required by the code.
Buildings with high ventilation requirements should try to ensure that each building has a certain windward side. The wind shadow area behind the building is about three times the height of the building, which is much larger than the sunshine spacing. If the buildings are placed in the same row only considering the sunshine interval, there will be no direct windward side for the buildings in the back row, which is very unfavorable for the ventilation of the buildings in the back row. However, if we blindly pursue the distance between wind and shadow, it will contradict the principle of saving land. This is a pair of contradictions, and a reasonable choice should be made in the design process.
It is of practical significance to solve the problem of natural ventilation of buildings in Leng Xia hot area in winter to reduce the power consumption of air conditioning. Through the shape design, orientation and layout of the building, the maximum natural ventilation can be obtained according to the local wind rose map. The height, length and depth of buildings have great influence on natural ventilation, and natural ventilation of buildings can also be strengthened by rational arrangement of trees. Simple rectangular body, with long doors and windows facing the dominant wind direction in summer as far as possible, has better ventilation effect. When the building plane is concave or L-shaped, its notch should face the dominant wind direction in summer as far as possible; The depth of building plane should not be too large, which is conducive to the formation of through flow. Under normal circumstances, good ventilation effect can be obtained when the plane depth is not more than 5 times the clear height of the floor; For buildings with unilateral ventilation, the depth should not exceed 2.5 times of the clear height.
Linear buildings are conducive to natural ventilation, with the smallest shape coefficient and easy to meet various energy-saving indicators. In summer, the main rooms are arranged on the windward side, and the auxiliary rooms are arranged on the leeward side. Corridor-style buildings are deep and save land, but only one room has a good orientation, so it is difficult to organize indoor flow and it is not conducive to heat dissipation. The relative arrangement of doors and windows can make the ventilation line short and straight, reduce the circuitous and resistance of airflow and ensure the wind speed. If the corridor of the inner corridor building is long, a vent can be opened in the middle, or the stairwell can be used as the air outlet, which can form a through airflow and improve the ventilation effect.
3.3. Application of solar energy technology
The application of solar energy technology in architecture mainly involves photoelectric and photothermal aspects. Photoelectric technology mainly uses photovoltaic cells to provide electricity, which can be uploaded to the national grid in addition to building for personal use. This paper mainly talks about the application of photothermal technology in architecture.
Many years ago, domestic solar water heaters have been accepted by the market, and residents have a high enthusiasm for spontaneous installation and use, and the use effect is good. Since then, the application of solar photothermal technology has a good market prospect and mass base. However, the problems of low thermal efficiency, nonstandard installation, disorder and many hidden dangers in early products have brought us a new topic-building integration.
Building integration emphasizes that solar energy products and building engineering design should be planned, designed, constructed and put into use simultaneously with building engineering. Its advantage is that in the planning stage, the effective hours of sunshine can be calculated, and the roof, wall and other parts of the building where the heat collector can be installed can be arranged in the area where the maximum sunshine can be obtained, and at the same time, the sunlight can be prevented from being blocked by installing the heat collector in the back row building.
At present, all-glass solar vacuum tubes are popular in the domestic market, and the mature collectors abroad are flat collectors. The flat plate collector has the advantages of long service life, high stability and recycling. However, due to the high cost of flat plate collectors and the poor performance of some low-priced flat plate collectors, their development lags behind, but the development of flat plate collectors in solar energy industry will be unstoppable.
According to the national standard GB50364-2005 "Technical Specification for the Application of Solar Hot Water Systems in Civil Buildings", solar hot water systems are divided into three systems: centralized hot water supply, centralized-decentralized hot water supply and decentralized hot water supply. According to the system operation mode, it can be divided into three types: natural circulation system, forced circulation system and DC system. At the beginning of the design, we should work closely with Party A and manufacturers to choose an applicable, reliable and effective systematic way for integrated design.
Nowadays, solar hot water products have been developing in the direction of building components, gradually solving the contradiction between small high-rise buildings and high-rise buildings due to limited roof area; The separation of the collector from the water storage tank makes it possible for the collector to be installed on the window wall, balcony railing and external air conditioning louver of the building facade.
At the beginning of planning and building scheme, it is necessary to closely cooperate with water supply and drainage, electrical and other majors to accurately calculate the area of the collector required by the building, reasonably determine the shape of the building and the roof form, and provide reasonable and safe initial conditions for the installation of the photothermal and photoelectric collector components, so that they can be integrated into the building and become the constituent elements of the building, rather than ugly building accessories.
4. Conclusion
In fact, the international view of green building has a long history, but the domestic attention has increased recently. The real green building covers many circulatory systems and has the concept of whole life cycle, which is a very huge building system. Therefore, the formulation of green building should be more cautious from the engineering point of view. At this stage, if it is an architectural design industry, it is relatively easy to accept and implement a project as an energy-saving building. Because architectural design is only a part of the whole practice, it will become more and more difficult to cooperate with the outside world in the implementation process. We should adjust the design methods that we have always been accustomed to and put the concept of energy saving in the initial stage of design. In the initial scheme stage of the project, equipment engineers were invited to participate in the joint study on how to save energy in the building, thus setting energy-saving targets and establishing basic energy-saving technical measures at the initial stage of the project. There is still a long way to go to fully implement the green building, which requires every architect to devote himself to study and research, and Qi Xin will work together to achieve the energy-saving goal.
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