Technical specification for heating metering
JCJ 173—2009
Description of terms
order
1 general rules
2 terminology
3 Basic clauses
4 heat source and heat station heat metering
4. 1 measurement method
4.2 Adjustment and control
5- Building heat metering
5. 1 measurement method
5.2 Adjustment and control
6 household heat metering
6. 1 General provisions
6.2 Measurement method of heat distribution of radiator
6.3 household heat meter method
7 Indoor heating system
7. 1 system configuration
7.2 System control
General rules for 1
1.0. 1 The purpose of heating metering is to promote the reform of urban heating system, ensure the heating quality and reform the charging system, and realize energy saving and consumption reduction. Energy-saving control technology such as room temperature adjustment is an important premise of heat metering, and it is also a basic means to reflect the energy-saving effect of heat metering. Article 38 of the Energy Conservation Law of People's Republic of China (PRC) stipulates that the state shall take measures to gradually implement the system of household metering and charging according to the heat consumption for buildings with central heating. New buildings or energy-saving renovation of existing buildings shall be equipped with heat metering devices, indoor temperature control devices and heating system control devices in accordance with regulations. Therefore, this procedure takes household heat metering as the starting point, and specifies the heat metering mode, measuring instruments and construction requirements, as well as the corresponding energy-saving control technology.
5 technical specification for heating metering
1.0.2 this procedure is applicable to new construction, reconstruction and expansion of civil buildings and the reconstruction of existing civil buildings.
1.0.3 This procedure closely focuses on the promotion of heating metering and energy saving targets, leaving a large technical space and room. There is no mandatory way, method and apparatus for heating metering, and all localities can choose independently according to their own specific conditions. In particular, several methods of household heat metering have their own shortcomings and there is no perfect method. Need to choose a more suitable measurement method according to the specific situation.
2 artistic language
2.0.4 The heat metering device includes a heat meter for heat settlement, as well as instruments and meters for several different user heat sharing methods.
2.0.5 Heat metering devices include heat meters that meet the product standards of CJ 128, and other heat metering devices that are managed and used by users themselves and are not used for settlement.
2.0.6 Household heat metering can be divided into two ways from the perspective of metering and settlement. One method is to measure buildings with a building heat meter, and then allocate them by households. The other is to use the user's heat meter to measure and settle accounts directly by household. Among them, there are several ways to distribute according to households. In this issue, four distribution methods are listed, in no particular order, and their working principles are as follows:
Radiator heat distribution table method is a way to share the heat of users through radiator heat distribution tables installed on each group of radiators (hereinafter referred to as heat distribution tables).
The flow temperature method is a way to share the heat of users by continuously measuring the temperature difference between the inlet and outlet of radiators with vertical pipes or independent household systems, combined with the measured flow ratio relationship between each vertical pipe or independent household system and the hot population.
On-off time area method is a way to control the electric on-off valve installed on the inlet branch pipe of each household heating system through the thermostat, and share the heat of users according to the on-off time of the valve and the building area of each household.
Household heat meter method is a way to share users' heat through household heat meters installed in each household. When the allocation is based on the user's meter, the building or heating station needs to determine a thermal settlement point, and the total calorific value is allocated by the household meter. This method is different from the direct measurement and settlement of household heat meters. When the user meter is directly settled, the settlement point is determined on each household heating system, and the heat meter located in the building or heating station can no longer be used for settlement; If there is an independent heating system in public areas, it is necessary to consider who will bear this part of the heat.
2.0.7 Room temperature control includes two control functions, one is automatic room temperature constant control, and the other is manual active adjustment of set temperature.
3 basic provisions
3.0. 1 This article is mandatory. According to the Energy Conservation Law of People's Republic of China (PRC), new buildings and existing buildings should be equipped with heat metering devices in accordance with regulations. At present, many projects only reserve the installation location of heat meters, and do not really have the conditions for heat metering, so this article emphasizes the need to install heat meters to promote the realization of heat metering.
3.0.2 This article is mandatory. The heat settlement between heating enterprises and end users should be based on heat meters. The heat meter for settlement shall meet the relevant national product standards, and the metrological verification certificate shall be within the validity period of verification.
3.0.3 Nine articles, such as the Metrology Law of People's Republic of China (PRC), stipulate that the metrological administrative department of the people's government at or above the county level shall carry out compulsory verification on the public standard measuring instruments, the highest standard measuring instruments used by departments, enterprises and institutions, and the working measuring instruments listed in the compulsory verification catalogue of trade settlement, safety protection, medical and health care and environmental monitoring. Those who fail to apply for verification according to regulations or fail to pass the verification shall not be used. The catalogue and management measures of working measuring instruments subject to compulsory verification shall be formulated by the State Council. Other standard measuring instruments and working measuring instruments shall be regularly verified by users themselves or sent to other metrological verification institutions for verification, and the metrological administrative department of the people's government at or above the county level shall conduct supervision and inspection.
According to "Metrology Law", the heat meters used in thermal settlement points should be checked first and periodically, and the heat meters and heat distribution meters not set in thermal settlement points, such as radiator heat distribution meters, should have qualification certificates and type inspection certificates according to product standards.
3.0.4 Heat metering and energy-saving transformation should adopt technical and management means, and indoor thermal comfort should not be sacrificed for energy-saving heating, or even the room temperature is not up to standard. Of course, it is unreasonable that the indoor temperature is too high, and there is no need to keep the original room temperature too high when decorating.
6 technical specification for heating metering
3.0.5 Only under the premise of hydraulic balance, climate compensation and indoor temperature control metering can play an energy-saving role and truly reflect the energy-saving effect at the heat source; Among these energy-saving technologies, hydraulic balance technology is the premise of other technologies; At the same time, the indoor temperature control reconstruction of existing houses has a large amount of work, which also interferes with residents' lives. It should be carried out on the premise that the external network energy saving of heating system and the thermal insulation and energy saving of building envelope meet the standard.
This paper advocates giving priority to heat metering in reconstruction projects, so as to quantitatively evaluate the reconstruction effect, avoid false propaganda and other behaviors, encourage fair energy-saving market and create good market conditions for energy services. At the same time, while paying attention to heat measurement, we should also pay attention to the itemized measurement of heat source water consumption and power consumption.
3.0.6 The selection of heat meter should be based on flow and pressure drop, not directly based on pipe diameter. Theoretically speaking, the design flow is the maximum flow, and the flow should not reach the design flow when the heating load does not reach the design value. Therefore, most of the working time of the heat metering device is below the design flow, so according to experience, this article suggests that the heat meter should be selected according to 80% of the design flow. At present, when selecting the heat meter, whether the flow range, design pressure and design temperature of the heat meter are suitable for the design conditions are ignored, and the heat meter is selected according to the pipe diameter rather than the flow range of the instrument, which leads to the heat meter working in the high error zone. Generally, the indicators that represent the flow characteristics of heat meters mainly include initial flow qVm (some data are called minimum flow); Minimum flow qVt, that is, the flow from the maximum error zone to the minimum error zone (some data are called boundary flow); Maximum flow qVmax, rated flow or ordinary flow qVc. When selecting heat flow timing, it should be ensured that its flow always works between qVt and qVn. Flow characteristics of mechanical heat meter.
Installing a flow sensor on the reflux pipe is beneficial to reduce the ambient temperature of the instrument, prolong the battery life and improve the working conditions of the instrument. It has been suggested that installing a heat meter in water supply can prevent users from stealing water. In fact, only installing a water supply meter can't measure the stolen water, nor can it recover the loss of stolen water, and it will also make the working environment of the heat meter worse.
This article stipulates that the heat meter should store the daily heat supply of the local heating season, so as to facilitate the inspection and traceability of the operation and management level in the heating season. In the case of disputes between residents and heating enterprises on heating effect, it can be judged retrospectively by heat meter, and there have been successful cases in Beijing; By comparing the outdoor measured daily average temperature records with daily heating records, we can check whether the actual operation of heating enterprises is actively regulated according to meteorological changes. This paper puts forward that the heat meter has the function of data remote transmission and expansion, and it is also convenient for monitoring, management and meter reading.
Usually, in order to meet the requirements of instrument measurement accuracy, a straight pipe section is needed. In some places, although the heat meter is equipped with a straight pipe section, it is wrong to set a variable diameter section between the straight pipe section and the meter. At present, the installation of some heat meters can ensure the measurement accuracy without straight pipe section, which is also feasible and very useful for the reconstruction project of heating system. In the case that the history is not indicated by the instrument manufacturer, the length of the straight pipe section on the upstream side of the heat meter should not be less than 5 times the pipe diameter, and the length of the straight pipe section on the downstream side should not be less than 2 times the pipe diameter.
This happened during the pilot test. Because the clock calibration of heat meter is inconsistent, there is an error in statistical data processing, which affects the work, so I would like to remind you.
3.0.7 At present, counterfeit thermostatic control valves and balance valves occupy a high proportion in the market. Many manual valves pretend to be thermostatic control valves, and many valves without pressure taps and measuring instruments also pretend to be balance valves. These fake and shoddy products can not achieve the function of regulation, but also waste a lot of energy. The purpose of this article is to require strict management.
3.0.8 At present, the water quality problem of central heating is more prominent, which leads to frequent problems such as radiator corrosion, water leakage and control equipment blockage. It is urgent to formulate reasonable and feasible standards and strictly implement them, and the national standards for system water quality requirements are being formulated.
4 heat source and heat station heat metering
4. 1 measurement method
4. 1. 1 heat sources include thermal power plant, cogeneration boiler room and centralized boiler room; Thermal power stations include heat exchange stations and water mixing stations. There are two kinds of measuring instruments at the heat source, one is the trade settlement table, which is used for heat measurement of trade settlement between heat producers and heat buyers. For example, a heating station supplies public buildings, and the heat fee is settled by the meter, so a heat meter must be used here; The other is enterprise management table, which is used to calculate boiler combustion efficiency, count output energy consumption, and calculate pipe network loss combined with building measurement. The measuring device here does not need to be used for thermal settlement, and the measuring accuracy can be relaxed. For example, orifice flowmeter or elbow flowmeter is used to measure flow, and temperature sensor is used to calculate heat.
7 technical specification for heating metering
4. 1.2 It is suggested to install a heat metering device on the return pipe of the primary pipe network, because the temperature difference of high-temperature water is large, the flow rate is small and the pipe diameter is small, which can save the investment of metering equipment; Considering the low backwater temperature, it is suggested to install heat metering device on return pipe Road. If there are specific requirements for measurement and settlement, the measurement location should be selected as needed.
4. 1.3 It is convenient to connect the power supply at the heat source or heating station, so it is recommended to use the mains power supply with power-off protection.
4. 1.4 measuring the power consumption alone in the heat source is helpful to analyze the composition of energy consumption, find energy-saving ways, and choose and take energy-saving measures.
4.2 Adjustment and control
4.2. 1 This article is mandatory to effectively reduce energy waste. In the past, boiler room operators "watched the sky burn" by experience, and the effect was not very good. In recent years, the pilot practice found that the energy consumption of heating is not mainly wasted in the cold period, but in the early and late cold period. Because heating is not adjusted according to climate change, a lot of energy consumption is wasted. The automatic heating control device can automatically adjust the water supply temperature and flow according to the load change, and realize the optimized operation and on-demand heating.
An automatic heating control device should be installed at the heat source, and the optimal working conditions in this period can be predicted according to the current outdoor temperature and the operating parameters of the previous days through the thermal characteristics identification and working condition optimization program of the boiler system, so as to realize the operation guidance and adjustment of the system user.
Climate compensation device is a kind of automatic heating control device, which is simple and economical, and is mainly used in thermal power stations. It can automatically adjust the heating output according to the outdoor climate change, realize on-demand heating and save a lot of energy. The climate compensator can also set the time-sharing control mode as needed. For example, for office buildings, different room temperature requirements can be set at different time periods, with normal heating during working hours and on-duty heating during off-hours. Combined with climate compensator, the system has many adjustment modes and is flexible. In addition to the water supply temperature of the user, the monitoring object can also include the backwater temperature and the indoor temperature of the representative room. The controlled object can be the electric regulating valve on the heat source side or the frequency converter of the water pump.
4.2.3 The requirement of variable frequency speed regulation of water pump is to emphasize the importance of quantity regulation. The heating system has been using quality adjustment for many years, which can't save the electric energy of the water pump well. Therefore, quantity control has been paid more and more attention. At the same time, with the application of indoor flow control methods such as thermostatic radiator valve, variable frequency speed regulation of water pump has become an indispensable control method. Variable frequency speed regulation of water pump is an important link of system dynamic control and an important means of water pump power saving.
In recent years, the technology of variable frequency speed regulation of water pump has been popularized rapidly, but it can't solve the unreasonable problem of pump design and selection, and the design and selection of water pump can't be ignored because of variable frequency speed regulation control.
In recent years, the frequency conversion speed regulation technology of water pump has been popularized rapidly, but it can't solve the problem of unreasonable design and selection of water pump, and the design and selection of water pump can't be ignored because of frequency conversion speed regulation control.
It is beneficial to speed regulation and energy saving to adjust the performance curve of pump with steep drop.
At present, there are three main control methods of frequency conversion speed regulation:
1 Control the constant pressure difference between the inlet and outlet of thermal power station: This method is simple and easy to operate, but the flow adjustment range is relatively small and the energy saving potential is limited.
2. Control the pressure difference of the most unfavorable loop of the pipe network to be constant: this method has a large flow adjustment range and obvious energy saving effect; However, it is necessary to set up a pressure sensor at each thermal entrance to detect, compare and control at any time, and the investment is relatively high.
3. Control the backwater temperature; This method has slow response, long lag time and relatively poor energy-saving effect.
4.2.4 The purpose of this article is to separate residential buildings, national buildings and other buildings with different heat consumption laws in the pipe network system, so as to realize independent time-sharing and zoning regulation and save energy. For the system with separable pipe network, it can be adjusted and controlled separately at the source of the pipe network, and for the system with inseparable pipe network, it can be adjusted separately by regulating valve at the thermal entrance of heat users.
4.2.5 In the past, the miniaturization of heating stations was limited by the requirement of manual duty and the increase of investment cost. Now with the improvement of automation, the heating station has been unattended. At the same time, the popularization of assembled heating stations has greatly reduced the investment and land occupation of small stations, and has begun to have the foundation for popularization. With the continuous improvement of building energy-saving design index, especially after the implementation of three-step energy-saving in residential buildings, small stations and graded pumps will become an important development direction.
The reasons why this paper recommends the use of small thermal power station technology are as follows: