The greenhouse gas represented by carbon dioxide leads to the continuous warming of the earth. Addressing climate change and advocating a low-carbon life have become the consensus of all mankind. Under this consensus, low-carbon economy has developed rapidly
1 Introduction
The greenhouse gas represented by carbon dioxide leads to the continuous warming of the earth. Addressing climate change and advocating a low-carbon life have become the consensus of all mankind. Under this consensus, low-carbon economy has developed rapidly, and low-carbon building has become one of the hot issues after green building and sustainable building. However, like green buildings and sustainable buildings, the concept of low-carbon buildings is too broad. In reality, there is no corresponding design standard and evaluation system, which can not give architects the greatest design guidance. Therefore, it is necessary to reuse the concept of "passive architecture". Passive architecture takes the use of passive technology as the core, reconstructs the relationship between people, buildings and climate, changes the existing building construction mode, realizes low energy consumption in the whole life cycle of buildings and minimizes greenhouse gas emissions. The development of passive buildings in China is conducive to promoting the realization of low-carbon buildings.
2 concept and history of passive architecture
Passive architecture is not a new concept. "Passive" is a literal translation of English "passive", which originally means to induce and obey, and takes its meaning of "let nature take its course". If passive architecture is defined as "a building that conforms to the natural principles of sunshine, temperature and wind in nature and tries not to consume conventional energy", the history of passive architecture can be traced back to the era of hunting and agricultural civilization.
2.1 production stage of passive building
As early as the Neolithic age, human beings excavated pits and built semi underground caves where conditions permit; After entering the agricultural civilization, human beings combined with local conditions, used wood, bamboo, grass and even large animal bones as materials, and used various passive means to build houses, such as the Eskimo combined cave dwelling and fire pond to build an ice house, the Montezuma fortress of Indians, etc. During this period, the level of productivity was relatively low. Human beings should constantly struggle with nature to maintain their own survival. In the process of building construction, people have been unconsciously using local resources according to local climate conditions. People's response to nature, mainly climatic factors (temperature, sunshine, wind speed, wind direction, etc.) presents a passive relationship, and maintains a basic balance with the earth's environment. The architecture of this period can be called "simple passive architecture".
2.2 development stage of passive architecture
After the industrial revolution, especially in the 1920s and 1930s, people have made rapid development in science and technology, and the threat of nature to mankind has become weaker and weaker. With the maturity of heating and refrigeration technology, people can actively control the indoor temperature and humidity to meet people's comfort requirements, which makes the climate factor gradually disappear from the architectural design. However, this construction mode that deviates from the climate consumes and wastes a lot of energy and brings great environmental changes. Environmentalists even believe that human beings have begun to threaten nature, as exemplified by the destruction of the global ecological environment. Therefore, human beings should protect nature through civilized activities. This trend of thought is also reflected in the field of architecture. In 1933, American architects William Keck and Fred designed and built a house with solar heating through south windows, and put forward the concept of "solar house" for the first time. Since then, many American architects have devoted themselves to the research and optimization design of passive solar buildings, compiled design manuals and architectural atlas, and built a number of influential passive solar demonstration buildings.
2.3 mature stage of passive architecture
After the 1980s, the reduction of energy prices and the accumulation of public wealth weakened the interest of all sectors of American society in passive solar buildings. Therefore, the research and practice of passive buildings were transferred to European countries. In 1988, Bo Adamson of Sweden and Feist of Germany wanted to design a passive house without "active heating and air conditioning". In the following two decades, they carried out systematic research and testing, and formed a set of passive building technology and construction specifications. However, perhaps due to language, the concept of passive architecture has not attracted people's attention for a long time. Until 2005, after the sharp rise of world energy prices, passive architecture was favored in European countries because of its unique research starting point and gradually mature design, construction and evaluation system. In 2009, passive buildings were identified as national building standards or future urban development plans by some European countries. The European Parliament also proposed that new buildings must meet the standard of "passive housing".
3 Analysis of obstacles to the development of passive buildings in China
The development of passive architecture has gradually become the mainstream trend in the construction industry. At this stage, many factors such as basic research, design concept and investment payback period of passive architecture hinder its development in China.
3.1 insufficient research on passive building foundation
The essence of passive architecture is that under the specific regional climate and solar radiation conditions, and under the condition that the building can operate "naturally", the combination of indoor air temperature, relative humidity, air velocity and average radiation temperature can meet the needs of human basic thermal sensation in a relatively long time. When it cannot be met, The heat or cooling capacity to be supplied is relatively small. The passive building scheme design must have basic design basic conditions, mainly including accurate and reliable basic scientific data of indoor and outdoor design, appropriate building thermal design and indoor and outdoor wind field calculation theory and method. The basic conditions of these designs are based on the distribution law of building climate and energy resources, the demand for indoor thermal comfort and other related scientific research. At present, the domestic academic circles have not fundamentally studied and solved these basic scientific problems in passive architectural design, which leads to the lack of passive architectural design standards and hinders its development to a great extent.
3.2 passive design has not been paid enough attention
Passive architecture requires architects to make reasonable decisions on architectural layout, orientation and energy system in combination with climate factors in the formation stage of architectural scheme, so as to form a scheme of comprehensive energy consumption, environment and architectural art. However, the regulation theory and method of the indoor thermal environment of modern buildings are based on the concept of "unlimited energy and resources and unlimited natural environmental capacity". People's demand for the indoor thermal environment of buildings is realized through refrigeration and heating equipment. In addition, the current building energy-saving design standards in China do not consider the factors of passive design, so most architects take the climate problem as an optional parameter in the design process, ignore or even give up the regulating effect of regional climate and solar radiation resources on the indoor thermal environment, and pay more attention to the function and beauty of architectural space, It is considered that energy saving is the responsibility of HVAC designers, which hinders the implementation of passive buildings in China to a certain extent.
3.3 the payback period of passive construction investment is not clear
According to the development experience of foreign passive buildings, the economic cost of building passive buildings is higher than that of ordinary buildings. A. Audenaert and other scholars conducted economic analysis on passive buildings, low-energy buildings and standard buildings in Belgium. According to the research cases, he made break even time tables for three types of buildings under the change of energy price. The analysis shows that when the building is used for the 19th year, the energy consumption of passive buildings is equal to that of conventional buildings; In the 24th year, the energy consumption of passive buildings is equal to that of low-energy buildings; In the future, the total energy consumption of passive buildings is lower than the other two (as shown in Figure 1). Therefore, in the long run, the additional construction cost at the initial stage can be recovered by reducing heating and other expenses in a predictable period.
However, because passive buildings are new things in China, the increase of construction cost will put passive buildings in a disadvantageous position in the market. Specifically, it is not clear whether passive buildings are economical and reasonable, how much economic benefits they can bring to consumers, and how long the investment payback period is, Thus, construction developers and the public are unwilling to take the initiative to accept passive buildings.
3.4 lack of government economic incentive policies
At present, the development of passive architecture in China is in its infancy. For most people in China, this concept is still relatively unfamiliar. The national policy on the development of passive buildings has not been established. The energy conservation and emission reduction measures formulated by government departments are mainly aimed at the multi pollution structure with coal as the main energy consumption due to the energy composition of "poor oil, less gas and more coal", while relevant policies have not been formulated for the development of passive buildings. There is no corresponding tax reduction, subsidy or other incentive measures for relevant enterprises and personnel who save energy due to the construction of passive buildings, and no corresponding mandatory measures are taken for buildings whose design is not combined with the climate, which also leads to the reluctance of architectural designers, developers, consumers and other stakeholders to accept passive buildings.
4 countermeasures and suggestions for the development of passive architecture in China
To develop passive buildings, we should not only make full use of the market to adjust supply and demand, but also take administrative means with the help of the government to improve relevant laws and regulations, so as to finally form a good development pattern dominated by the government, market operation and social participation.
4.1 strengthen the basic research of passive buildings
Domestic theoretical research on passive architecture is relatively few, the concept definition is vague, and the basic theoretical research is lack. At the same time, most of the existing passive building standards are based on the neutral climate characteristics of cold winter and cool summer areas in Europe. China has a vast territory, covering many climate zones from south to north. The climate changes greatly, and many areas belong to cold or hot extreme climate zones, which means that the current passive building standards may be difficult to achieve. Therefore, we must be based on the national conditions, determine the effective flexible scope and specific parameters, and formulate the design standards of passive buildings in line with the regional characteristics of our country.
4.2 pay attention to passive design
Designers are the soul of architecture. Passive architecture can only be realized by passive design. Most of China's traditional buildings reflect the principle of passive design. For example, the quadrangles in Beijing form a microclimate through the enclosure of ring corridors and movie walls, so as to achieve warm winter and cool summer, and realize energy conservation and comfort. Therefore, the development of passive architecture requires architects to respect nature, combine local climate characteristics, and make the architectural layout, spatial form, structure and other aspects show adaptability to the climate according to different factors such as solar radiation, temperature, humidity and wind in different climate areas, so as to fundamentally reduce energy consumption.
4.3 establish a scientific construction economic evaluation system
Using building energy consumption simulation and other technologies, and using the triple bottom line theory proposed by British scholar John Elkington in 1997, this paper comprehensively evaluates the whole life cycle of buildings from three aspects: economic benefits, social benefits and environmental benefits. The whole life cycle of buildings not only includes the process from project site selection, planning, design, construction to operation, but also extends forward and backward on this basis, forward to the mining, transportation and production process of building materials, and backward to the natural degradation of garbage or resource recycling after building demolition.
4.4 formulate effective economic incentive policies
Foreign experience shows that the recognition and support of the government is an important guarantee for the promotion of passive architecture. At the initial stage of promoting passive buildings, European governments provided nearly 20000 euros of financial support to families of passive building model houses and demonstration projects. The financial subsidies of the United States and the preferential loan system of Japan are the main policies of the state to promote passive construction by economic means. Chinese governments at all levels should learn from the development experience of foreign passive buildings, formulate corresponding economic incentive policies such as tax reduction and discount loans, innovate the investment and financing system, raise funds for the development of passive buildings and promote their development.
5 Conclusion
Based on the new concept of nature, science and architecture, passive architecture seeks the harmonious unity of man, nature and architecture, deepens and locks the focus into the process of architectural design, and emphasizes the use of passive technology to achieve the goals set by green buildings, sustainable buildings and low-carbon buildings, which has become the fundamental way to realize the above building types. Therefore, it is imperative and of far-reaching significance to reuse and pay attention to the concept of passive architecture, establish the theoretical framework, design standards, design strategies and evaluation system of passive architecture, and formulate and implement scientific, reasonable and operable economic incentive policies.
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