Green building under China's national conditions

China is a developing country with a huge population and limited land and resources. Therefore, the development of green buildings in China, the establishment of standards and the assessment must take into account China's national conditions.

Based on local conditions and suitable technology. On the one hand, in the eco-technical strategy, it is necessary to consider “measures for local conditions” and adopt appropriate technology strategies in traditional technology strategies, low- and medium-tech strategies, and high-tech strategies. On the other hand, when assessing, they must adapt measures to local conditions and seek truth from facts, and should make vertical comparisons. Development; horizontal comparisons should be conducted under the same or similar conditions.

Take into account the overall interests and local interests. Green buildings need to consider not only the environmental impacts of the country but also the global scope, such as saving farmland, saving water resources, reducing the energy consumption and CO2 emissions of building materials, etc., and also benefiting developers and users. The former has no direct interest in the developer and the user. It needs to be controlled through the formulation of laws and regulations. At the same time, there must be policy adjustment and support.

Taking into account the interests of users and developers is not only a direct driving force for the promotion of green buildings, but also a healthy and comfortable living and working environment for users.

Some Problems of Green Building under China's National Conditions

Save land and living patterns. “Large population and less land” are China’s national conditions. Therefore, at present and in the foreseeable future, most urban residents in China will live in apartment-style residential buildings. They will not be like developed countries in Europe and America, and most will live in free-standing units. Or a row of small houses. However, saving land is not only a matter of less occupied buildings, high density of buildings and a larger population density; it also needs to be considered from the aspects of “Foot Print” and “ecological value of land”.

"Foot Print" refers to the allocation of earth resources reserves and production according to the earth's land area. When a person living in a city or region lives according to a lifestyle, how much of the earth's land area is required for the consumption of per capita resources (including energy). Assessing the impact of a construction project on a piece of land resource A construction project's impact on a piece of land depends on whether the total ecological value of the piece of land is increased or decreased, and not only how much the building has occupied. To encourage construction projects to use wasteland and badlands, we must increase the ecological value of the site through project construction instead of “constructive damage”.

The resources of sloping land and wasteland around Beijing are very large. But why not use it? Because the current model is to let real estate developers engage in development and build houses. When a real estate developer goes to the suburbs, where the environment is good and the landscape is good (ie, the ecological value is high), where he goes to develop, the built house can be sold at a good price, and the result is often a constructive destruction of the surrounding environment and landscape. However, if the wasteland, sloping land and badlands pass policies are sold to individuals in the city (of course middle- and high-income earners), ownership will be given to him, and he will build houses through his own homes. In this way, the environment can be better, and the original badlands Ecological value can be improved. As for the infrastructure, the government will have the money to sell the land and use the money to sell the land to repair the infrastructure.

Also, around large cities with high GDP per capita, because it is difficult to retain agricultural production with very low per capita GDP and consider improving the environment, when implementing the “returning farmland to forests” policy and plan, the government subsidizes farmers to To plant trees, it is better to divide some of the land into small pieces and sell them to individuals who build houses for themselves. The government formulates plans to limit the volume ratio, limit the area, and specify the greening requirements. With 20% to 30% of the land to build a house, leaving 70% to 80% of the land to let the house to plant trees, to green, may be more than to allow farmers to use 100% of the land to plant trees, greening effect will only be good will not be bad. In addition, it is possible to carry out ecological measures that are effective for solar energy utilization, wind energy utilization, water reuse, rainwater utilization, roof greening, and vertical greening, and it is difficult to do high-rise residential buildings in cities. These positive ecological and environmental benefits can balance the negative impact of land occupation. In addition, the greening of households is a kind of consumer behavior and can also provide employment opportunities for farmers. The government gives subsidy to farmers to plant trees. It is an administrative measure. The government must spend money and it is difficult to ensure the effectiveness of greening.

energy. The energy issue in China is, first of all, energy conservation, making great efforts to improve energy efficiency and reducing energy consumption; followed by energy structure issues, and the development of new energy and renewable energy utilization issues. Energy is closely related to the environment. Considering the relationship between the two, we must balance our national conditions with national interests. For a long period of time in the future, in most cities, China’s energy structure is mainly coal-fired. China's coal reserves are much higher than oil and natural gas, and coal is used instead of oil and gas. It can be used in mega cities such as Beijing and Shanghai. The general cities, even big cities, must be carefully modified.

The improvement of the heating energy method must match the thermal performance technology of the building envelope. For example, in an attempt to use electric heating equipment with a low electricity price and low electricity prices, it is only when the high heat capacity, thermal inert envelope structure and high airtight windows and doors are required to ensure that the indoor temperature does not drop when the power is not applied during peak hours. too much. Nowadays, many electric heating commercial houses, households generally reflect the heating costs are too high.

Secondary decoration. In the new house that has just been constructed, residents must undergo renovations to dismantle and dispose of unused building components, equipment, and pipelines. This has resulted in enormous material, labor, and economic waste, and has even caused hidden dangers to house security.

Building materials. Clay bricks, local materials, low prices. However, because clay bricks are used to make earth and land is destroyed, the per capita arable land area in China is very small. Protecting cultivated land is very important and urgent. Therefore, the use of solid clay bricks must be restricted and prohibited.

wood. The country’s forest resources have been destroyed in a vicious manner. Indiscriminate harvesting has made it difficult to sustain the production of timber, which has led to restrictions on the use of timber. The North American and North European countries, which operate forests as their industries, have formed a virtuous circle of timber production, and generally use wood-structured houses;

Concrete. The energy consumption during production is large, the pollution is large, the building is difficult to recover when it is demolished, and the waste is difficult to degrade naturally. It is a building material that is not green, but at the present stage, it has to be used in large quantities because of economic and technological factors, and how it is economically acceptable. The use of abandoned concrete is worth studying;

Steel. From the point of view of the life cycle of construction materials, steel has the characteristics of high performance (cost) ratio, no pollution in use, and high green recycling rate and green building materials. However, at present, the core problem of domestic steel structure residential buildings is that The cost is high. Careful analysis is not caused by the high cost of the main steel structure, but high: a large number of connection fittings, fire prevention measures in accordance with the current fire regulations, and assembly of new wall materials. There is a concept that steel structures should be industrialized and highly assembled, and new lightweight walls should be used to reduce wet work. This is a technical route in developed countries with high labor prices, and China’s national conditions are The labor force is more and cheaper. China promotes steel structures from an ecological point of view rather than saving labor.

lawn. The current grassland introduced from abroad is not only resistant to trampling, but only to see, not allowed to enter, loses the function for outdoor activities on it; it also consumes a lot of water for irrigation, especially drought and water shortages. In the region, the problem is even more serious. And the ecological benefits of grassland are small, even negative. The solution is to, on the one hand, strictly restrict grasslands, especially large lawns without shrubs and shrubs. On the other hand, cultivate suitable grass species through plant and bioengineering techniques, develop foot-resistant lawns, and develop water-saving cultivation techniques. Irrigation technology.

Artificial wetland. Many cities in China have carried out “hardening” projects on rivers, thus losing the natural beauty of the natural water landscape on the one hand, and on the other hand “hardening” will cause damage to the ecological balance of aquatic life. In the planning of residential areas and landscape design, artificial wetlands can be created to replace the “hardened” water features. On the one hand, the water features of the residential areas tend to be natural, and at the same time, they can be used as measures for the deepening of water and rainwater. Constructed wetland technologies include seepage prevention of bottoms and slopes, planting of plants on the bottom and banks, selection and cultivation of aquatic organisms, recharge and overflow of water bodies, purification of water bodies, and protection of water quality.

Home air conditioning. In recent years, split-type home air conditioners have quickly and universally entered Chinese families, and their popularity has surpassed that of many developed countries. There is no fresh air supply for the split-type air conditioner, no ventilation is closed in summer, and the indoor air quality deteriorates. A large temperature difference between indoor and outdoor can also cause thermal shock and it is easy to catch a cold. Split-type air conditioners are not good for health and comfort does not equal health.

Residential partition wall sound insulation. The sound insulation performance of the wall follows the “law of quality”. In the past, the partition wall of multi-storey houses was mostly 24 brick walls with double-sided plastering. In recent years, the use of solid clay bricks has been restricted and eliminated, using lightweight wall materials and structures. But this has had an adverse effect on the sound insulation of the wall. In residential design, the architectural design should be coordinated with the structural design so that the split wall is a heavy, heavy wall. At the same time, construction holes should be avoided during wall construction. If the partition walls inevitably use lightweight infill walls, double walls or composite structures are required to ensure sound insulation performance meets the standard requirements.

The floor crash sound insulation. The poor isolation of floor crashes is also a long-standing problem in residential buildings. The “floating floor” approach is commonly used in collective housing in European countries. The “floating floor” has a good impact sound insulation performance, which can ensure that the floor impact sound insulation meets the first-class standard, and the increased investment is acceptable compared with the selling prices of medium and high-grade commercial housing, but it needs to be increased. 5 to 7 cm floor height. In a high-rise duplex apartment, the bedroom is arranged below the living room floor of the home, which can reduce the interference of the upper and lower households. However, tenants may not accept the concept of “going downstairs”.