Multi-perspective thinking on building energy efficiency?

The following is Zhongda Consulting to bring you about building energy efficiency for reference.

The country's ever-increasing construction, so that the number of building energy consumption is increasing, in 2000 China's building commodity energy consumption has accounted for 27.8% of the country's total commodity energy consumption.1 With the improvement of people's living standards, air conditioning is becoming more and more common, the total amount of energy consumption in the building and its share of the total energy consumption will continue to grow, the country's energy burden will be even heavier, and the risks posed by the high-speed growth of the economy to the natural environment are increasing, and the situation is becoming increasingly serious. Risks to the natural environment brought about by rapid economic growth are increasing, and the situation is becoming more and more critical. Under such circumstances, building energy conservation work must reverse the current serious backwardness and the overall slow progress for a long time as soon as possible, and move forward by leaps and bounds in accordance with the "Tenth Five-Year Plan" of the Ministry of Construction for building energy conservation, so as to make high-energy-efficiency and environmentally friendly buildings more and more fashionable, create a good working and living environment for the people, and enable the long-term sustainable development of the economy and society, while the building energy conservation work will continue to grow. Long-term sustainable economic and social development, and building energy efficiency is a systematic project, which involves a wide range of content. The following combines the current situation in China and abroad, from various aspects and angles to talk about building energy efficiency.

1, policies and regulations

1.1 the development of building energy-saving laws and regulations, improve building energy-saving management system governments in the 1970s after the oil crisis, are combined with the characteristics of their own countries, have formulated and implemented a series of building energy-saving laws, regulations, building energy-saving made clear provisions, and the establishment of a perfect energy management system as a guarantee for the implementation of these policies. The energy management system has also been established as a guarantee for the implementation of these policies. As early as 1972, Canada enacted a new law on energy saving in buildings; West Germany enacted a law on energy saving in buildings in 1976; Sweden implemented mandatory energy-saving regulations; France has enacted regulations on energy saving in residential buildings; Eastern European countries have also enacted and implemented corresponding laws in the past 10 years, which has led to the rapid development of energy-saving work in buildings. Japan is the country with the most complete energy-saving management system, and it has established a complete set of energy management agencies and consulting agencies from the government to the local level, specializing in the study of energy-saving issues. In addition, the general establishment of private energy-saving center organizations, exchange of experience with each other. Japan this top-down national building energy efficiency research, has achieved very good results.

1.2 Combining the actual development of building energy efficiency standards to ensure the implementation of energy-saving building certification and labeling system

a) Because of China's vast territory, the climate varies. According to China's national standard "building climate zoning standard GB50178-1994" 2, China's building climate zoning system is divided into five zones, respectively, the severe cold region, cold region, hot summer and cold winter region, hot summer and warm winter region and mild region. Building energy efficiency and climate conditions are closely related, different climate conditions should be different building thermal insulation requirements. The requirements for air-conditioning and heating in different regions are as follows: cold regions, mainly heating, and air-conditioning should be considered when the requirements are high; cold regions, heating and air-conditioning; hot summer and cold winter regions, air-conditioning and heating; hot summer and warm winter regions, mainly air-conditioning, and heating should be considered when the requirements are high; and mild regions, where part of the area requires heating or heating/air-conditioning. Therefore, in the development of building energy efficiency standards, the heat transfer coefficient (or thermal resistance) for the housing envelope also varies.

b) Because of the different uses of the buildings, the thermal insulation requirements of the buildings are also different, so the formulation of building energy efficiency standards are also different. Buildings in the same area for different purposes, due to different conditions of use, should not be uniformly all in accordance with the same model of thermal insulation requirements. And residential buildings and non-residential building requirements are different, for non-residential buildings of different types of building requirements are also different.

c) due to the different economic development in different parts of China, the difference between east and west, coastal and inland differences are large, then the requirements for the development of different standards or the implementation of different times.

d) implementation of the certification and labeling system for energy-efficient buildings energy-efficient building labeling and certification is one of the important strategies for the government to implement the building.

Through the assessment and labeling of energy-efficient buildings, it can make it easier for the public to understand the energy consumption of buildings or their impact on the environment, and motivate builders to use whether a building is energy-efficient or not as a marketing indicator. In foreign countries, there are many programs for energy-efficient product assessment and labeling, and they are often sponsored by central and local governments, industry associations, and third parties (e.g., environmental organizations, consumer associations, etc.). At present, 37 countries around the world have implemented the development of "marking", and 34 countries are using energy efficiency standards". It has been proved that through certification and energy efficiency labels, the following effects can be achieved: energy savings: constraining energy growth but not economic growth; easier quantification of the benefits; changing the behavior of manufacturers and guiding consumers; equal treatment of manufacturers, distributors and retailers; and very significant energy savings. Since many developed countries have a wealth of experience in energy saving, we can take the best of it in a practical way.

1.3 Adopt economic incentives to provide the necessary financial support for building energy conservation

From the experience of developed countries around the world, if there is a lack of substantial economic incentives for building energy conservation and the necessary financial support, and rely purely on the spontaneous behavior of the users and developers, as well as the mandatory implementation of the quality standards of the construction project, it can be of some use to new buildings, but the energy-saving renovation of existing buildings is not as effective. The energy-saving renovation of already constructed buildings has no effect at all . The government must make full use of financial and tax means to take a series of economic incentives to promote the smooth progress of building energy efficiency.

2, technical measures

2.1 energy-saving ideas of the overall planning of a large number of residential buildings in the planning of the overall idea of emphasizing the "people-oriented, the environment first" principle, to meet the applicability of residential, durability at the same time, puts emphasis on the "uniformity", focusing on environmental, energy-saving, energy-saving, energy-saving, energy-saving, energy-saving, energy-saving, energy-saving, energy-saving, energy-saving and energy-saving. ", focusing on the environment, energy saving, environmental protection three themes. Improve the taste of living space, enhance the city's brand.

2.2 Energy-saving measures for architectural design modern buildings in the design in addition to ensuring building safety, comfort, intelligence and ecological factors, should also focus on the effective use of energy and conservation.

2.3 Energy-saving Technology of Envelope Structure The energy-saving technology of envelope structure refers to the reduction of the use of energy consumption of the building through the use of wall thermal insulation (external thermal insulation, internal thermal insulation, self-insulation, sandwich thermal insulation and other technologies), doors, windows and roofing energy saving and other measures. Such as residential energy saving is through the envelope energy-saving design, to achieve than the traditional residential energy savings of 25% of the target, in combination with energy-saving design of equipment, to achieve the overall use of residential energy consumption reduction of 50% of the target by 2010 to implement the energy-saving 65% of the design standards.

2.3.1 wall insulation wall insulation is the outside of the main wall structure with adhesive materials to fix a layer of thermal insulation materials, and in the insulation materials on the outside of the plaster mortar or other protective decorations, in the root of the external wall, the daughter wall, balcony, deformation joints and other parts of the wall prone to "thermal bridge", the use of external insulation technology, can be significantly eliminate the "thermal bridge". "Thermal bridge" caused by heat loss. At present, the main ways are: polystyrene board insulation mortar exterior wall insulation, polystyrene board cast-in-place concrete exterior wall insulation, polystyrene granule slurry exterior wall insulation. Wall insulation is covered with a layer of insulation material on the inside of the wall structure, fixed in the wall structure by adhesive, and the outside of the insulation material for the protective layer and finish. Wall self-insulation refers to the wall itself through a series of new technologies, so that its thermal conductivity is extremely low, and even reached the degree of adiabatic. Such as Germany's TEUBERTMAGU2ICF system of housing, by both the thermal insulation layer is a disposable permanent environmental protection formwork EPS all-insulated building modules, using the block-type insertion after the concrete poured into. The wall is made of two 4.5cm thick EPS modules inside and outside, connected by connecting bridges (patented products), and the middle is filled with concrete as the perimeter load-bearing wall and subdividing wall, which belongs to the adiabatic concrete composite heat preservation and shear wall system, and the whole building is made of concrete, and its performance meets the requirements of the German energy-saving standards for buildings. TEUBERTMAGU2ICF is an adiabatic concrete composite heat preservation shear wall system, with strong integrity, light deadweight (about 50% lighter than the brick structure), good seismic resistance and long service life: its heat transfer coefficient is low, only 0.117-0.133W/(m2.K), and does not produce "thermal bridges", and it is soundproof, moisture-proof, and breathable, which provides a good living comfort; the material of the system is completely made of cement, sand, and concrete. The material of the system completely adopts cement, sand, stone, steel and so on without using clay bricks, which protects the land resources and fully meets the requirements of environmental protection; and it is an all-concrete structure, which can adapt to the requirements of complex shape and molding, and it can be used to build various styles of buildings with different building modules.

2.3.2 Doors and windows of energy-saving buildings, the main function of windows and doors is to get enough light under the conditions of the need to control the windows and doors in the sun when the sun is reasonable to get the heat, and in the absence of the sun to reduce heat loss.

2.3.2.1 Factors affecting energy gain from windows and doors Factors affecting the ability of windows and doors to gain solar heat include:

a) location and orientation of the window;

b) design of the window product (number of window apertures);

c) type of glass used;

d) number of internal and external shades.

2.3.2.2 Factors affecting heat loss from windows and doors Heat energy tends to flow from the warm side to the cold side. Doors and windows are the main factors constituting heat loss. We can reduce the heat loss of windows and doors through a reasonable configuration. The main ways of energy transfer in windows are: radiation transfer, convection transfer, conduction transfer, in addition to air leakage is also an important part of the window energy loss. The emissivity of the glass surface can be reduced through physical and optical principles, which can reduce the radiant heat transfer of the glass, i.e. the use of Low2E glass can reduce radiant heat transfer. Conduction losses in windows occur mainly through the insulating glass edge and window frames. These losses can be effectively reduced by improving the edge materials, using more insulating edge sealing materials, such as the Smiggle Warm Edge Sealing System and insulating window frame materials (e.g., plastic steel windows and doors, aluminum alloy windows and doors with broken bridges, etc.), as well as by improving the design of the window and door profiles. Convective heat loss is mainly generated by gas movement through the insulating glass spacer, if the spacer is too small through the air heat transfer is a lot. If the air spacer is too large, the warm air on the interior side of the warm glass surface will rise while the cold air on the exterior side of the cold glass surface will fall, creating convection and heat loss from the interior. The best insulating glass spacer thickness to minimize convection loss should be between 12 to 16mm, usually filled with special gases such as argon, ammonia to reduce convection loss, these gases are suitable for different spacer thickness.

2.3.3 Roof insulation and energy saving roof is the upper part of the building and the outside world in direct contact with the key parts of the thermal insulation and heat insulation of the building energy saving is of great significance. In order to achieve the purpose of energy saving, the roof can be set up vapor barrier and closed air between the layer, can choose to have water-repellent expanded perlite board, cement polystyrene board, polystyrene board and other kinds of thermal insulation materials. When flexible waterproofing is used on the outer surface of the roof, anti-sun radiation materials should be used. Soil cladding and grass-planted roofs have obvious thermal insulation effects, and water pressure is eliminated by "building sandwich anti-drainage combination". In the general waterproof layer with plastic convex plate, cover geotextile, waterproofing, drainage, soil retaining, water filtration, both green grass-roots level, but also the roof of the anti-drainage grass-roots level, to solve the problem of roof leakage and planting in the drainage and air permeability. With lightweight synthetic soil, lawn thickness of 20 ~ 30cm, the load of about 100kgPm2, increase the thermal resistance, to achieve the Ministry of Construction energy-saving standards. It is reported that the United States, Chicago City Hall roof 1840m2 roof garden demonstration project, can save $ 4000 per year cooling costs, roof garden than the traditional roof structure life long, this insulation layer can make the indoor temperature drop 2 ~ 3 ℃, is a kind of worth promoting the heat insulation layer.

2.3.4 Solar Energy Building

Solar energy is the most important energy in green energy, which is an inexhaustible natural energy. As early as in the 1930s, the United States began the experimental study of the sun room, and has built a number of experimental sun room. At the end of the last century, the world and the rise of the "sun roof" heat. In recent years, developed countries have a considerable level of "zero-energy houses", that is, completely by the solar photovoltaic conversion device to provide all the energy consumption required by the building, truly clean and pollution-free. Solar building basically has three forms: one is passive, generally simple structure, without any auxiliary energy building, through the building orientation of a reasonable arrangement and proper handling of building components, natural heat exchange to obtain solar energy, the use of solar energy. U.S. building experts invented the solar wall, the outside of the building wall with a thin layer of black perforated aluminum panels, which can absorb 80% of the sun's energy irradiated to the wall, the air being sucked into the aluminum panels by the preheating, through the wall of the pump pumped to the building, thus saving the energy consumption of the central air-conditioning. It is estimated that the cost of laying aluminum panels can be recovered from the cost of energy saving after 3 years, which is a type of passive solar room . The second is the active type, complex construction, high cost, need to use electricity as auxiliary energy building. There is a kind of active solar room, solar air collectors are arranged on the roof facing south, and the heated air is sent into the room by the fan after passing through the gravel heat storage layer. The auxiliary heat source is a gas hot air furnace, and a control and adjustment device is set up to determine the input ratio of the heat source according to the temperature of the air supply. Shenyang Huaxin International Development "Fairview Villa" ecological villa area using split heat pipe vacuum tube solar collector system, even in winter, rainy days can also ensure 24h hot water supply, solar energy use of the expected energy-saving rate of up to 60% or more, energy-saving effect is remarkable. Third, the "zero energy building", this building by the solar roof to provide all the energy needed for the building, installed on the roof of the 2 ~ 3kW solar cells, and grid-connected with the grid, but due to the high price of solar cells, the general promotion of the difficulties.

2.3.5 Application of new materials for energy saving the introduction of new building materials production technology, development and production of environmentally friendly, energy-saving building materials is an inevitable trend in the development of the building materials industry. As far as residential construction is concerned, the Ministry of Construction has ordered the elimination of a number of products that do not meet the requirements of energy conservation, measurement, environmental protection and other products and low quality products to ensure that the housing industry to resource-saving direction, such as solid clay bricks, hollow steel windows, log windows and doors, galvanized tubes, cast-iron faucets, etc., the wall material innovation is notable achievements.

2.3.6 HVACR energy saving heating energy air conditioning and refrigeration in the building has the initiative, the building energy saving will have a big impact, so we should be treated with caution . Air-conditioned buildings and air-conditioned rooms should be arranged in accordance with the following principles:

a) building plan and shape should be as simple as possible, reduce the length of the insulation wall;

b) air-conditioned rooms should be separated from the general room as much as possible and centralized arrangement;

c) the same indoor temperature and humidity parameters, the use of the same nature and muffling requirements for the air-conditioned room as far as possible adjacent to each other or the upper and lower floors of the opposite Arrangement;

d) in order to avoid the influence of solar radiation heat, should try to avoid the east-west arrangement and arranged in the top floor;

e) should try to avoid the immediate vicinity of high-temperature or high humidity room;

f) air-conditioning room at the corner of the building should not be set up on both sides of the external wall windows, in order to reduce the heat transfer and infiltration; air-conditioned rooms should minimize the area of the external window and should be Take sealing (airtightness level should not be less than Class II) and shading measures; external windows should be as far as possible south and north, avoiding east-west .

Air-conditioning system should be based on the use of air-conditioned rooms, and consider the flexibility and economy of the system operation and regulation, after technical and economic comparisons to determine, in order to achieve the purpose of economic energy saving. Air-conditioned room of the instantaneous load changes in large differences, should be divided into systems; the same time, respectively, the need for heating and cooling room, it is appropriate to set up a separate system; air-conditioned room required fresh air accounted for the proportion of air supply is very different, according to the proportion of those who are similar to set up a separate system; air-conditioned room of the area is very large, it should be set up according to the inner and outer areas of the system; high-rise civil buildings, as permitted by the conditions of the height of the building, it is desirable to Set up air-conditioning system in layers.

A building or an air-conditioned area which air-conditioning system, should be determined after careful technical and economic comparison. All-air fixed air volume single duct system can be used for the need for constant temperature, humidity, dust-free, no noise and other high-level environment occasions; all-air fixed air volume dual duct system can be used for air-conditioned areas need to control the temperature and humidity of a single room, or due to the shape of the building, the use of the building and other reasons, so that the distribution of its hot and cold load complex places; all-air variable air volume system can be used in air-conditioned areas of the room need to be adjusted separately, but temperature and humidity of the room temperature and humidity, but the temperature and humidity of a building or an air-conditioned area should be determined. Room temperature, but the temperature and humidity control precision is not high places; fan coil plus fresh air system of air conditioning system can realize the independent adjustment requirements of the occupants, it applies to hotel rooms, apartments, hospital wards, large office buildings, etc.; induced machine-type system can be used for multiple rooms need to be individually adjusted control of the building, but also can be used for the outside area of a large building; window air-conditioning machine-type system and split air-conditioning machine-type system of the Strong independence, adapted to the building air conditioning room layout dispersed, small area, the requirements of different running time occasions; cabinet air conditioning system can be used for independent small buildings; a variety of heat pump system independence, can be used throughout the year to require air conditioning, hot and cold loads close to the place.

3, building energy efficiency testing and analysis

Building energy efficiency testing includes a wide range of content:

a) building envelope; exterior wall temperature, heat flow; thermal bridge parts of the exterior wall (beams, beams, structural columns, core columns) inside and outside the surface temperature, heat flow; windows and doors, both inside and outside the surface temperature, heat flow, door and window airtightness indexes; roof inside and outside the surface temperature, heat flow; surface temperature, heat flow; ground surface temperature, heat flow surface temperature, heat flow; ground surface temperature, heat flow; building indoor room temperature, balcony temperature;

b) building indoor and outdoor air temperature, relative humidity;

c) horizontal, east, south, west, and north solar radiation intensity;

d) indoor thermal comfort (PMV, PPD);

e) indoor air velocity under natural ventilation;

f) air-conditioning consumption under air-conditioning condition; and p>f) power consumption under air-conditioning state, etc.

The test should be conducted in a cycle of 3 to 5d, and the test room adopts continuous observation and continuous recording.

We can conduct energy-saving tests on a building or a region of the building and analyze and evaluate them in order to guide and promote the development of energy-saving buildings.

4. Concluding Remarks

Above, we have fully discussed and thought from multiple perspectives from the importance of building energy conservation, national policies and standards, technical measures of building energy conservation and testing and analyzing of building energy conservation, etc., and we believe that building energy conservation is directly related to the national resource strategy, sustainable development and environmental protection, and it is an important, urgent and arduous task for the construction industry It is an important, urgent and difficult task for the construction industry, which deserves the attention of the whole society.

More about the engineering/service/procurement category of the tender writing production, to enhance the winning rate, you can click on the bottom of the official website customer service free advice:/#/?source=bdzd