Wen/Wang Wei With the diversification of residential buildings and their technological progress, different heating methods have become an inevitable trend of development. However, due to the different perspectives of considering the problem, the government, developers, design units, property management departments and households will come to different nodes and difficulties: everyone faces multiple choices and it is difficult to choose the heating mode that has been used for decades. The impact.
The heating system that has been used for decades is a vertical single-tube tandem system in buildings such as multi-storey buildings. This system form is the most reasonable and most durable in the welfare distribution of housing during the planned economy period. Five or six are somehow heating. Therefore, residential heating inevitably causes problems such as temperature imbalance. Even so, if the construction unit checks and accepts the good project, it can solve the above problems before delivery. The "congenitally insufficient" heating system will inevitably lead to waste or refuse to pay the heating fee, which will inevitably make the traditional heating system the target of other heating modes.
The first challenge was the wall-mounted gas water heater heating system, followed by the electric heating film heating system. These two heating methods are set up by households, which can exempt the inconvenience of property management and transfer some of the development costs. In addition, the technical and economic arguments put forward by some experts indicate that the heating costs are lower than the central heating method, so Beijing’s The household heating trend is still strong. In fact, many people in the industry worry that in the northern regions, strictly speaking, it is cold and cold. In multi-storey, medium and high-rise residential buildings, the current technical level is not suitable for household heating. In the villa buildings with low density of residence, the advantages of household heating can be reflected. Moreover, community residents who use these two heating methods have also raised various complaints through the media. The biggest opinion is that the heating costs are much higher than the promises made when buying a house. This may be caused by the fact that the basic data and actual deviations when measuring the economic indicators of household heating methods are large, such as the energy consumption indicators of buildings. According to China's current building energy-saving residential heating system, the current normal operation is the best example. However, I do not know when to start, the design of residential heating system is increasingly ignored in the design unit, HVAC engineers have no conditions to carefully design; in the construction process, the layer subcontracting engineering phenomenon also makes the construction unit without conditions and careful construction, and even Some southern "contractors"
To undertake the construction of the natural gas charging standard operating fee remarks 1.40 yuan / m313. 54 yuan / m2, quarter 125 days heating, electricity costs 0.50 yuan / degree 1.8 yuan / m317. 23 yuan / m2, the quarter water fee is 1.10 yuan / ton, including The living standard of the duty staff is 20.6W/m2. According to this, the performance indicators and design selection principles of various enclosure structures are proposed, but there is no corresponding test, acceptance criteria or regulations, that is, some The acceptance of energy-saving residential projects is only to assess whether they have energy-saving measures. Therefore, on the one hand, it has affected the use of many new products. On the other hand, it has caused the price competition of similar energy-saving products, shoddy, and ultimately led to excessive building energy consumption. This is also the main reason why the heating energy consumption in Beijing is high and energy saving is not saved for many years.
The electric heating film heating method should be used when it is inconvenient to use other heating methods in Beijing. Although electric heating film heating has the advantages of no system heat loss, flexible control and comfort, but because Beijing's power source is a thermal power plant, it is not suitable for the energy cascade utilization, energy efficiency and urban sustainable development strategy. Advocating, it should not be used as a new buying point or so-called technical content of housing. Professor Jiang Yi of Tsinghua University and other articles published: "At present, the average thermoelectric conversion efficiency of China's large thermal power plants is 33%. In addition to the transmission loss, the efficiency of electric heating rice is only 30%. It is far lower than 170% of cogeneration, and also lower than 8590% of coal or gas heating. France, Switzerland and other countries use part of electric heating because of their abundant water resources, power generation is mainly hydropower and nuclear power. It is mainly based on thermal power generation, and it uses electric heating method, which actually increases the pollutant discharge by 2 times compared with the direct heating of the boiler house. From the perspective of environmental protection, the direct heating method of electric heating is also not desirable ["Residential Industry" 2000.11]. So, some people say that "electric film is an environmentally friendly product", it is too narrow, because environmental protection is not a requirement of a building, a community, or a city. As for the electric heating film, it can balance the electricity load in winter and summer, and receive the reward from the power supply department. For example, the developer should consider the specific conditions of the construction project C or the design unit. The specific analysis should not be adopted blindly. . In addition, according to news reports, the Beijing Municipal Government Office issued the “Notice on Promoting the Use of Clean Energy in the Suburbs of the Cityâ€, which mentioned that “there is a heat storage function, and the use of low-temperature electric heating will enjoy the low-floor heating electricity concessions. Electricity price." However, the "heat storage function" is not a pie that falls from the sky. Zhang Zongyu of the China Textile Industry Design Institute has published an article pointing out that the regenerative electric boiler heating system requires about 120150 m3 of water storage tank per 10,000 square meters of heating area, covering an area of ​​about 100 m2. If boilers and pumps are added. Water treatment equipment and its ancillary facilities, together with high and low voltage power distribution equipment, covers an area of ​​about 250 square meters. Due to the low temperature and long time in winter, it is necessary and reasonable to use central heating for residential buildings. However, due to changes in fuel and boilers, the scale of central heating is in a certain management mode, the smaller the better. In the "Beijing Youth Daily" published in the 59th edition of the 19th edition on October 19, 2000, "the comparison of several typical heating methods" can be seen that the installation cost of the gas boiler installed on the roof is 80 yuan / m2 [ Building area), operating cost is 1318 yuan/m2, season; in other materials, the actual operating data of this heating mode is also seen: 2 floors underground and 18 floors above ground in a certain district of Beijing, with a building area of ​​about 18,000 square meters. In the residential building of the meter, the 18th floor is partially the equipment room, and the 17th floor is the household. When the 15th floor is facing the north living room, the lowest temperature is 19.7X: most of the time is 2022X:C measured), according to various measured data. The result is as follows: 1.40 yuan/m3, commercial star and above hotels) yuan/m3. Another district in Beijing, using coal-fired boilers for central heating, the heating fee charged to the residents is 19 yuan / m2, heating period. Obviously, the high-rise residential buildings adopt the heating mode of “small concentration†according to the building. Because there is no intermediate link such as heat exchange station and outdoor pipe network, and the output efficiency of the gas boiler is much higher than that of the coal-fired boiler, the fuel price will not cause the operation cost. increased badly. As for the large-scale thermal power plants, the environmentally-friendly coal-fired boilers have been changed to the heating units of gas-fired boilers, and the operating costs have been greatly increased. The reasons are manifold. In the notice of the General Office of the Municipal Government, preferential policies are provided for new or existing residential projects under construction or use of natural gas, and the recovery investment portion of operating costs can also be reduced. Other factors that increase operating costs can also be overcome by improving service quality and introducing competitive mechanisms.
However, the indoor piping design of the central heating system also faces many difficulties. With the promulgation and implementation of the design and management documents for heating metering systems in Jilin, Harbin, Dalian, Tianjin, Beijing, etc., not only the single-tube series system has become the target of criticism, but also the double-tube vertical system has to be eliminated. Then, whether the system of setting up the heat meter by households can sing the one-man show of central heating, there is still no guarantee of theory and practice.
In addition, some commercial housing, or high-end residential, has considered the annual air-conditioning as a new buying point. It is important to note that the premise of this success is still the level of building energy efficiency, as this directly affects the operating costs of air-conditioning throughout the year. The current level of building energy efficiency in China is still far lower than that of developed countries. Especially in summer, there are still differences of opinion on some theoretical issues. However, the annual air-conditioning has also raised the issue of whether it is good to concentrate or to be divided. As mentioned above, due to factors such as climate and thermal engineering in Beijing's multi-storey, middle-rise and high-rise residential buildings, central heating is necessary in the winter and the advantages outweigh the disadvantages. In summer, centralized air conditioning is not. In addition, if you want to use a set of piping system, water pump and end equipment (such as fan coil) for both winter heating and summer air conditioning, not only the corresponding technology and product guarantee, but also the winter and summer load conditions. It’s like wearing clothes. If you are familiar with the living clothes, if the clothes are fluffy, when the weather is not too cold, you can wear them without the children. When the weather is cold, plus the comprehensive comparison table of different heating methods in Beijing. : Heating method is equivalent to primary energy initial investment operation fee Public part of the building part of the operation energy management fee GJ/m2 year yuan / m2 yuan / m2 yuan / m2 year yuan / m2 year heat and power cogeneration central heating *0.32605010.62 coal Boiler room central heating 0.63505010.12 natural gas boiler room centralized heating 0.60455027. 3*1 electric heating boiler central heating C does not store heat]1.71455063*1 electric heating boiler central heating C regenerator]1.80805035*1.5 household gas furnace 0.45101018.70 Home electric heating film or electric heating 1.200443.30 family C phase change type) electric heating 1.20015022. 3*0 air heat pump C with auxiliary power supply] 0.660150*23.8*0 water source heat pump (each independent) 0.4060150*16.1 cogeneration The investment only covers the external network and the heat exchange station, excluding the power plant; the operating fee is 16 yuan/GJ.2 electric heating film construction and installation fee is about 60100 yuan / m2 editor's note.
It has included initial investment in summer air conditioning.
4 small central heating system costs will not be so high, see the editor's note above.
39 yuan / kWh.
20 yuan / kWh.
Wearing a child, such a piece to wear when wearing two pieces, winter in the South is not a problem. If in the cold northern part of the country, the live down of the down and other thick cotton, and then wear it when two pieces are not chic. As for the water source heat pump system, although the winter and summer load conditions can be better balanced, the temperature of the water source is a major factor affecting the system efficiency. According to experts, the winter water source temperature should not be lower than 15X: the summer water source temperature should not be higher than 35X: . Therefore, heating equipment (such as boilers) and cooling equipment C such as cooling towers can not be less, only the capacity and land area are reduced, one investment due to the high price of indoor equipment, making the overall investment higher than the central heating with split air conditioner . Here, I recommend to you Professor Jiang Yi of Tsinghua University and other comprehensive comparison results for different heating methods in Beijing C. “Residential Industry†2000. 11, the same as above. The value of “equivalent primary energy†can represent national interests, “ The initial investment and operating expenses can reflect the interests of developers and households. It has a good guiding role in the choice of heating methods. However, due to the lack of a unified understanding or conclusion on certain issues, it is bound to be benevolent and wise.
In short, the basis for doing a good job in HVAC is to further strengthen building energy efficiency. The current energy-saving focus is on balconies and exterior windows. China's current building energy-saving standards take into account the poor performance of the external wall envelope structure. The proposed body factor and window-wall area ratio are relatively small, and many construction projects have made breakthroughs, especially the outer window area. It should be noted that when the large outer window area of ​​the force port ensures the heat transfer coefficient of the glass and the window frame is low, it is advantageous to obtain free thermal solar energy indoors in the winter and reduce the heating energy consumption, but in summer, if there is no good external shading At the facility, the air conditioning load generated by the solar radiant heat entering the room through the glass will multiply.
On the issue of electric heating, Professor Jiang Yi also pointed out: "Developing the development of centralized heat supply for cogeneration, this is the basic national policy for writing the white paper of China's second-first century. It should be supported and guaranteed from all aspects. As long as it is possible to access thermoelectricity If the joint heating network is used, it should be accessed on request, and other methods are not allowed." "The biggest problem in China's power system is the difference between peak and valley. Direct electric heating will not help to slow down the peak-to-valley difference. Vigorously develop heat pump technology to achieve high-efficiency heating or develop phase-change heat storage electric heating to solve the problem of peak-to-valley difference. It is a reasonable way to expand the power load."
The bad competition of project contracting should also attract the attention of the construction unit. It is said that some heating single contracting or renovation projects have not been designed or even drawings, and are determined on site by so-called experienced construction personnel. If you do not pay attention, it will cause considerable losses to developers and owners. Decoration and decoration units should also pay attention to such problems in order to avoid small losses.
Column Editor: Gan Yu S
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