Energy saving technology

First, new water-saving technologies.

1. Popularize and apply new water-saving equipment.

1. 1 Promote the use of high-quality pipes and valves.

Because galvanized steel pipes are easy to rust, it will cause water pollution, and long-term idle use will release rusty water, causing waste. At the same time, if the joint is corroded, it will also leak water. If new types of pipes such as aluminum-plastic composite pipe, steel-plastic composite pipe, stainless steel pipe, copper pipe, PP-R pipe, pe pipe and PVC-U pipe are adopted, this kind of waste problem can be well solved.

Valve is also one of the most commonly used fittings in building water supply and drainage, and its type and quality can also affect the water quality. Generally speaking, globe valves are more tightly closed than gate valves, and gate valves are more tightly closed than butterfly valves. Under the same conditions, we should choose a more water-saving valve.

1.2 Promote the use of water-saving sanitary appliances and water distribution appliances.

A good set of equipment can play a very important role in saving water resources. For example, shower heads generally spray more than 20 L of water per minute, while water-saving nozzles only need about 9L of water per minute, saving water by half. It can be seen that the water-saving performance of sanitary ware and water distribution equipment directly affects the water-saving effect of the whole building. Therefore, when choosing water-saving sanitary ware and water distribution equipment, we should not only consider the price factor and users, but also examine their water-saving performance. Vigorously promoting the use of water-saving sanitary ware and water distribution equipment is an important aspect of building water saving.

(1) Replaced the ordinary faucet with ceramic core water-saving faucet and inflatable faucet. Under the same water pressure, the water-saving faucet has a better water-saving effect than the ordinary faucet, and the water-saving amount is 3%~50%, mostly between 20% and 30%. Moreover, the higher the static pressure, the greater the water output of ordinary faucet and the greater the water saving of water-saving faucet. Therefore, buildings (especially water distribution points with excessive water pressure) should be equipped with water-saving faucets to reduce waste.

(2) Use a small-volume water tank toilet. At present, China is promoting the use of 6L water tank water-saving toilet. Designers should advise users to use small-volume water tank toilets while ensuring the normal operation of the drainage system. You can also refer to the practice of foreign countries (Israel) and adopt a two-stage flushing water tank: when flushing urine, the flushing volume of the two-stage flushing water tank is 4L (or less); When flushing stool, the flushing volume is 9L (or less).

(3) urinal and urinal water tank with time-delay self-closing faucet and photoelectric control faucet. The delayed self-closing faucet automatically closes after a certain period of time, which can avoid the phenomenon of long running water. The water outlet time can be adjusted within a certain range, but after the water outlet time is fixed, it is not easy to meet the requirements of different users, and it is more suitable for places with relatively simple nature, such as stations and docks. Photoelectric control faucet can overcome the above shortcomings and can be used in many places without manual touch operation, but the price is higher. At present, photoelectric controlled urinals have been installed and used in some public buildings.

2. Improve the hot water supply circulation system.

With the improvement of people's living standards, the application of centralized hot water supply system in residential quarters has also been fully developed, and the quality of building hot water circulation system has gradually become more and more important. Most centralized hot water supply systems have serious waste, which is mainly reflected in the fact that after the hot water device is turned on, hot water that meets the use temperature cannot be obtained in time, and only part of cold water can be discharged before it can be used normally. This part of cold water did not produce the due use benefit, so it was called invalid cold water. This waste of water flow is caused by many reasons such as design, construction and management. If the balance of multi-loop resistance of hot water circulation system is not considered in the design, the circulating flow will appear short flow in the loop near the heating equipment, which will reduce the water temperature in the loop far from the heating equipment; Unreasonable arrangement or calculation of hot water pipe network leads to a great difference in inlet pressure between cold water and hot water in mixed water distribution device. If the pressure of cold water is greater than that of hot water, a large amount of cold water will often flow out when using the water distribution device, and then the temperature can be adjusted to normal. The water-saving effects of adopting multiple circulation methods in the same building are branch pipe circulation, riser circulation and main pipe circulation in turn, but the engineering cost of each backwater system is from high to low in this order. Article 5.2. 10 of the revised Code for Design of Water Supply and Drainage in Buildings (GB500 15-2003) puts forward two circulation modes, namely, vertical pipe circulation, main pipe circulation and branch pipe circulation, vertical pipe circulation and main pipe circulation. The main pipe circulation is cancelled, and it is emphasized that the circulation system should ensure the circulation of hot water in vertical pipes and thousand pipes, which is of great significance to water saving and energy saving. Therefore, when selecting the circulation mode for the central hot water supply system of newly-built buildings, the water-saving effect and project cost should be comprehensively considered, and the branch pipe circulation mode or vertical pipe circulation mode should be selected according to the specific conditions of building nature, building standards and regional economic conditions, so as to minimize or even eliminate the waste of invalid cold water.

3. Control the overpressure outflow

In the current Code for Design of Building Water Supply and Drainage in China, although there are some restrictions on the maximum pressure of water supply pipe fittings and household branch pipes, this is only from the perspective of preventing the damage caused by excessive pressure of water supply pipe fittings, not from the perspective of preventing overpressure outflow, so the pressure requirements are too loose and basically have no effect on limiting overpressure outflow. If this aspect is not considered in the design, it will cause great waste of water resources. Therefore, the pressure of water supply system should be reasonably limited according to the actual situation of overpressure outflow of building water supply system.

Article 3.3.5 of Code for Design of Water Supply and Drainage in Buildings stipulates that the domestic water supply system of high-rise buildings should be vertically partitioned, and the hydrostatic pressure of the lowest sanitary ware distribution point in each partition should not be greater than 0.45MPa, and it should not be greater than 0.55MPa under special circumstances. The optimum water pressure of sanitary ware is 0.20MPa~0.30MPa, and most of them are in overpressure outflow. According to relevant data, when the hydrostatic pressure at the water distribution point is greater than 0. 15MPa, the outlet flow of the faucet increases obviously. It is suggested that decompression measures should be taken when the hydrostatic pressure of the lowest sanitary ware distribution point in the high-rise partitioned water supply system is greater than 0. 15MPa.

4. Develop the second water resources

Domestic drainage from buildings includes domestic sewage and domestic wastewater discharged in people's daily life. Domestic wastewater includes all kinds of drainage, such as cooling drainage, bathing drainage, washing drainage, laundry drainage and kitchen drainage. Miscellaneous drainage without kitchen drainage is called high quality miscellaneous drainage. Reclaimed water refers to all kinds of non-drinking water that can be mixed into life, municipal and environment after being treated to meet the specified water quality standards.

In China, domestic sewage accounts for 69%, hotels and restaurants account for 87% and office buildings account for 40%. If collected and purified into reclaimed water, it can be used as miscellaneous water for buildings and cities, such as toilet flushing, road cleaning, urban greening, car washing, building construction, fire fighting and so on. , thus replacing the same amount of tap water, which is equivalent to increasing the water supply of the city. Taking a university as an example, under the current technical conditions, the investment of reclaimed water project is about 3,000 yuan /m3 ~ 4,000 yuan /m3, and the water treatment cost is about 1.5 yuan/m3. The average daily water consumption of this school is about 8000m3. If the planned water consumption is calculated by 2.4 yuan /m3, the annual water fee is as high as more than 7 million yuan. If unplanned water use and increasing water fee are considered, the annual water fee will exceed100000 yuan. In order to save water resources, at present, combined with the ecological campus planning, the school has set up reclaimed water recycling equipment in many buildings such as student dormitories and swimming pools to realize water supply in different quality while ensuring water quality. According to incomplete statistics, this can not only save water for the school about 1200m3 every day, but also save water for the school about10 million yuan every year, with remarkable benefits.

Because the reclaimed water project is a systematic project that affects the whole building, it is difficult to transform the existing building. At the same time, due to its high upfront investment, it is difficult for developers to accept if they want to formulate standards and specifications, at least for now. However, in the long run, it is imperative to build the second water source-reclaimed water in the case of increasingly scarce water resources. It is a powerful measure to realize sewage recycling and save water resources, and it is the inevitable direction of water-saving development in the future.

5. Rainwater utilization

Rainwater utilization is a process of collecting rainwater and treating it with certain facilities and chemicals to achieve a certain water quality index. Similar to reclaimed water, treated rainwater, as an available water resource, can be used for toilet flushing, urban greening, landscape water and other water that meets the quality standards of reclaimed water. The general structure of building rainwater collection is to lead the rainwater on the roof to the rainwater grit chamber located underground through the conduit, and the precipitated rainwater flows into the reservoir, which is pumped to the miscellaneous pool and sent to the waterway system after chlorination and disinfection. In order to solve the problem of dust and acid rain, the rain two minutes before the rain is generally skimmed. At present, many countries in the world have carried out research on rainwater utilization to save water resources and reduce the burden of local water use and sewage treatment. For example, Germany, Japan and other countries have designed rainwater collection facilities on buildings in some cities. The collected rainwater can be used for fire fighting, community greening, car washing, toilet flushing and supplementary cooling water, and can also be used for drinking by residents after advanced treatment. Rainwater Utilization System of Arched Baseball Fields in Tokyo, Fukuoka, Osaka and Nagoya. The water collection area is 16000 ~ 35000 m2, and the storage tank volume is 1000~2800m3, which is used for toilet flushing and greening after sand filtration and disinfection. The annual rainwater utilization of each system exceeds 30,000 tons.

6. Setting and pressurization of fire storage tanks

The fire water consumption of high-rise buildings is often far from the domestic water consumption, and the design flow of fire water supply system may be many times that of domestic water supply system. Because the fire water storage requirements meet the total fire water consumption during the fire. Therefore, in the case of the joint construction of fire-fighting water and domestic water storage tank, because the capacity of fire-fighting water storage tank is much larger than that of domestic water storage tank, the domestic water supply stays in the storage tank for too long, and the residual chlorine is exhausted long ago, which leads to the deterioration of water quality. Therefore, in order to ensure that the water quality in the pool meets the hygienic standard, all the water stored in the pool (including fire water storage) should be replaced regularly. Therefore, when the water storage capacity of the two systems is quite different, the water storage tanks of the two systems should be built separately, which can not only prolong the water exchange period of fire storage, thus reducing the waste of water, but also ensure the quality of drinking water meets the requirements. At the same time, the fire storage tank should be used as much as possible with swimming pools and waterscapes to realize multi-purpose, reuse and recycling of one water. At the same time, high-rise buildings or residential areas should use fire pools and pressurized pumps as much as possible. Fire water storage capacity should be calculated according to the water demand of the largest high-rise building. This can not only avoid many technical problems brought by fire pressure to various architectural designs, but also save engineering construction and equipment investment, reduce operating costs and facilitate centralized management. At the same time, it can avoid the waste caused by a large number of fire water storage tanks and regular water change.

7. Strengthen water meter management

7. 1 Increase the setting of total water meter in residential area.

Obviously, the setting of water meter plays a vital role in the control of water quantity. Increasing the total water meter in the community and analyzing the water balance with each household water meter will help to find the hidden danger of water leakage. The so-called water balance test refers to the actual test of the water system of the unit by water users, and analyzes the balance relationship between input water and output water. For example, Shanghai Jiaotong University, Xuhui Branch, after the water balance test, found many hidden dangers of water leakage. After the improvement of the water supply system, remarkable results have been achieved in saving 30,000 tons of water every month and paying 6,543.8+0,000 yuan of water fee every year. During the water balance test, it is necessary to pay attention to the installation of water meters at the following locations: 1. The starting point of household branch pipes (or water pipes that need to be metered and charged in public buildings), the water inlet pipes of multi-storey buildings (the doors of each building) and the water supply systems of residential quarters (or institutions, colleges and other units); 2. The high-rise building is located in the following positions: the low-area inlet pipeline directly supplied by the external network; The pipeline before the secondary water supply in the high area is introduced into the water collection tank; For high-rise buildings with pool-water pump-water tank water supply mode, water meters should be set on the outlet pipe of water tank when conditions permit; Each water supply riser of the high water supply system is provided with a water distribution meter (or two risers are provided with a water distribution meter); Third, meet the requirements of water balance test and rational water use analysis of other parts of the pipeline.

7.2 Improve the accuracy of water meter measurement

Due to the problems of type selection and water meter itself, the accuracy of water meter measurement is poor. If the model of water meter in some buildings is too large and the water consumption is small, the pointer of water meter basically does not move. About 40% water does not meet the precision requirement of 4%. The accuracy of water meter measurement is related to the evaluation of leakage control and the countermeasures taken. Therefore, effective measures should be taken to improve the accuracy of water meter measurement.

7.3 Limited service life

According to the relevant provisions of the Verification Regulation of Measuring Instruments for Compulsory Verification (Trial) issued by the State Bureau of Technical Supervision, household water meters are only subject to compulsory verification for the first time, and they are used within a limited time and replaced when due. However, due to the lack of effective measures to implement the above provisions, most water meters under construction are used indefinitely. Due to the mechanical wear of the parts of the water meter itself, the longer the service life of the water meter, the lower the accuracy. Therefore, in order to ensure the working accuracy of water meters, it is necessary for property departments and water supply companies to conduct regular inspections on water meters.

7.4 develop IC card water meter and remote water meter

At present, household water meters are widely installed in residents' homes, which brings inconvenience to residents' lives. At the same time, when residents decorate indoors, they often cover the originally installed water meters, which brings great difficulties to the maintenance and management of water meters. In recent years, China's residential design began to set the water meter relatively centrally or uniformly on the first floor (or equipment floor), or set the water meter in the tube well. These designs will increase the water supply pipeline and cost, and at the same time increase the construction difficulty and the inconvenience for residents to check the water meter. It can be seen that the application technology of water meter in China should develop to IC card water meter and remote water meter system.

8. Vacuum water-saving technology

In order to ensure the washing effect of sanitary ware and sewer, vacuum technology can be applied to drainage engineering, with air replacing most of the water, and relying on the high-speed gas-water mixture generated by vacuum negative pressure, the sewage and dirt in sanitary ware can be washed quickly, so as to save water and discharge dirty air. A complete vacuum drainage system includes: sanitary ware with vacuum valve and special water absorption device, sealed pipeline, vacuum collection container, vacuum pump, control equipment and pipeline, etc. The vacuum pump generates a negative pressure of 40~50kPa in the drainage pipeline, sucks the sewage into the collection container, and then the collected sewage is discharged into the municipal sewer by the sewage pump. All kinds of buildings adopt vacuum technology, saving more than 40% water on average. If used in office buildings, the water saving rate can exceed 70%.

Second, new energy-saving technologies.

1. High-rise buildings should make full use of the available water in the municipal water supply network.

It is difficult for high-rise buildings and urban pipe networks to fully meet their water supply requirements. In some engineering designs, the water in the pipe network is directly pumped into the storage tank, which is lost in vain, especially when the storage tank is underground, but it is not economical and reasonable to convert all the water into negative pressure. On the lower floors of high-rise buildings, there are often public service commercial facilities with large water consumption, such as public bathrooms, laundry rooms, garages, hair salons, etc., which account for a considerable proportion of the total water consumption of buildings. If all the water is pressurized by water storage tanks and pumps, it is undoubtedly a great waste. For example, a building is a 32-story comprehensive high-rise building with a garage on the ground floor 1 to the second floor, and the water consumption for car washing is 25m3/d; The water consumption for commercial services on the ground 1-3 floors is 25m3/d; The water consumption of office buildings on floors 4-6 is12m3/d; Greening, spraying and other water consumption is 65438+100m3/d; The water pressure of urban pipe network can ensure the water supply on the third floor and below, and the water supply from the fourth floor to the sixth floor can be interrupted by the pipe network. If all this water diversion is borne by the water storage tank on the second floor underground through the pump house, the annual electricity consumption is about 17500 kWh, so we should pay attention to make full use of it.

2. The problem of decompression and throttling

When describing the problem of excessive outlet pressure of water supply pipeline, it is mentioned that it is easy to cause overpressure outflow and waste water resources. For energy conservation, this is often easily overlooked. Because even after zoning, the hydrostatic pressure of the lowest water distribution point in each district is still as high as 300kPa-400kPa. When calculating the design flow, the rated flow of sanitary ware is obtained on the premise that the outflow head is 20kPa~30kPa. If the pressure reduction and throttling measures are not taken, the actual outflow of sanitary ware is 4-5 times of the rated flow. It brings the disadvantages of wasting water and high water pressure, and it is easy to produce water hammer, noise and vibration, which leads to the damage and rupture of pipe fittings.

The effective measure of reducing pressure and throttling is to control the outlet pressure of water distribution point in water supply system. Some design units put forward to install orifice plates and pressure reducing valves in front of water distribution points to avoid overpressure in some water supply points, provide users with suitable service faucets, and make the water pressure distribution in vertical zones more uniform. Therefore, the problem of pressure reduction and throttling should still be paid attention to after the vertical partition of water supply system in high-rise buildings.

3. Domestic water supply system and fire water supply system

In the water supply design of high-rise buildings, the domestic water supply system and the fire water supply system should be set separately, because the two water supply systems have different requirements for water pressure. According to the regulations, the domestic water supply system should be partitioned according to the hydrostatic pressure of not more than 300kPa~400kPa, and the fire water supply system should be partitioned according to the hydrostatic pressure of not more than 800kPa. Therefore, if the water pressure value is divided according to the fire protection requirements, the domestic water supply pipeline will be overpressure, resulting in excessive water supply and other problems; If the pressure reducing valve is used to reduce pressure and throttle all the year round, it will inevitably lead to the waste of electric energy; If zoning is carried out according to the requirements of domestic water supply pressure, the number of water pump units will increase relatively. Therefore, from the point of view of saving energy and saving expenditure, saving engineering investment and facilitating operation and management, the domestic and fire water supply systems should be set separately. This is convenient to reasonably determine the pressure value of the vertical partition of each water supply system and avoid energy waste.

4. Reasonable selection of variable frequency water pump

Commercial energy-saving variable-speed water pump should be selected as the water supply mode without regulating water tank. The application of variable speed water pump can avoid the waste of water and electric energy caused by the calculation of the most unfavorable water supply situation in the traditional water supply system, and it has broad prospects in today's shortage of various resources. Similarly, in the hot water supply system, with the emergence of automatic control technology of water pump, various monitoring instruments and new temperature-sensitive materials, the operation of circulating pump can also adopt automatic control system with variable flow and lift. It can be considered to install a simple water flow indicator at the water distribution tap, or install a temperature sensing element at the farthest water distribution point to transmit the signal to the control system of the circulating pump, and instruct the pump to stop and rotate randomly according to the different water distribution conditions of hot water, so as to change its operating parameters, thereby saving electric energy consumption. Compared with common water supply equipment, frequency conversion speed regulating device saves electricity 10%~40%.

5. Boiling water supply system

Boiling water supply is generally to set up electric water heaters or gas water heaters in each floor of the boiling water room. Electric water heaters are flexible and should be used when the water supply is small; Fuel gas is suitable for use when water consumption is high. For office buildings, small water heaters can also be used, which is more convenient and energy-saving.