Heating station control system suitable for southern central heating

Abstract

The utility model relates to a novel heating station control system suitable for southern central heating. The novel heating station control system comprises an efficient plate heat exchanger, a circulating water pump, a frequency converter, a secondary pipe network water supply pipe temperature and pressure sensor, a secondary pipe network water return pipe temperature and pressure sensor, a field controller, an electric control valve, a climate compensator and the like. The components can be assembled to form a standardized heat supply control system. The climate compensator can be arranged in a heating station, and can also be arranged in a heat supply control center and other places where outdoor temperature collection and data transmission are convenient. The system is wide in application range, capable of adapting to changes of user loads, flexible in operation and adjustment, energy-saving, consumption-reducing, high in safety and reliability, capable of adapting to the situation that load changes are large at the initial stage of development of current southern central heating users, capable of supplying heat according to needs, capable of guaranteeing rights and interests of accessed users, energy-saving, emission-reducing and good in economic benefit and social benefit.

Description

Technical Field

[0001] This utility model relates to a heat station control system suitable for centralized heating in southern China, especially suitable for situations where the load changes significantly during the early stages of the development of centralized heating users in southern China. Background Technology

[0002] Central heating is a vital infrastructure for urban economic and social development, and it is widely popular due to its energy-saving, low-pollution, production-friendly, and convenient features. Currently, with rising living standards, the demand for centralized heating in winter is growing stronger in southern cities.

[0003] In recent years, some areas south of the "heating line" have begun to gradually plan or implement centralized heating. The heating season in the south is short, the investment recovery period is long, and residents' acceptance of centralized heating varies, leading to significant uncertainties in market expansion. It is not advisable to simply copy the heating model used in the north; instead, a heating model suitable for the southern climate and heating characteristics needs to be explored, tailored to local conditions. Summary of the Invention

[0004] The problem this utility model aims to solve is to provide a heat station control system suitable for centralized heating in southern China. This control system has a wide range of applications, can flexibly adjust its operation to adapt to changes in user load, saves energy and reduces consumption, and has strong safety and reliability. It can adapt to the situation where the load changes are large in the early stage of the development of centralized heating users in southern China, and provide heating on demand, which not only protects the rights and interests of connected users but also promotes energy conservation and emission reduction.

[0005] The technical solution of this utility model is: a control system for a heating station suitable for centralized heating in southern China, including a plate heat exchanger, a field PLC controller, a primary-side electric regulating valve, a secondary-side electric regulating valve, a climate compensator, and a soft water tank; the primary-side inlet and outlet of the plate heat exchanger are respectively connected to the primary network supply pipe and the primary network return pipe; a primary-side electric regulating valve is installed at the primary-side outlet; the secondary-side outlet and inlet of the plate heat exchanger are respectively connected to the secondary network supply pipe and the secondary network return pipe; a first temperature regulator is installed on the secondary network supply pipe. The system includes a primary pressure transmitter and a secondary temperature transmitter and a secondary pressure transmitter, respectively. The secondary water supply and return pipes are connected via a secondary-side electric regulating valve. The soft water tank is connected to the secondary inlet of the plate heat exchanger via a makeup water pump. A circulating water pump and a frequency converter controlling the circulating water pump are installed between the secondary inlet of the plate heat exchanger and the secondary-side electric regulating valve. The temperature and pressure transmitters are connected to the field PLC controller via control lines. The field PLC controller and the climate compensator are connected via wireless communication.

[0006] A standardized heating control system, as described in this utility model, is formed by components such as a high-efficiency plate heat exchanger, a circulating water pump and frequency converter, temperature and pressure sensors for the secondary water supply pipe and the secondary water return pipe, a field controller, primary and secondary side electric regulating valves, a climate compensator, and an online multi-functional ion passivation treatment device. An online multi-functional ion passivation treatment device is installed between the secondary side electric regulating valve and the circulating water pump.

[0007] The plate heat exchanger is equipped with filters at both the primary and secondary inlets.

[0008] The plate heat exchanger has a heat transfer coefficient ≥3500W / m 2 High-efficiency plate heat exchanger with a temperature of .℃.

[0009] The temperature transmitter is an intelligent integrated temperature transmitter. The pressure transmitter is an intelligent pressure transmitter.

[0010] The soft water tank is equipped with a liquid level sensor, and the liquid level sensor and the field PLC controller are connected via a control line using a 4~20mA DC or RS485 signal.

[0011] This utility model's heating station control system is suitable for centralized heating in southern China. Compared to traditional heating stations in the north, this system has a higher degree of automation and more flexible operation and adjustment. While ensuring heating supply, it significantly reduces operating costs and can adapt to the expansion of the end-user market, requiring only a 30% heating access rate to be put into operation. This utility model aligns with people's livelihood needs and saves energy, effectively promoting the high-quality development of heating infrastructure in southern cities.

[0012] This utility model has a wide range of applications, can adapt to changes in user load, can operate and adjust flexibly, save energy and reduce consumption, and has strong safety and reliability. It can adapt to the situation where the load changes are large in the early stage of the development of centralized heating users in the south, and can provide heating on demand. It not only protects the rights and interests of connected users, but also promotes energy conservation and emission reduction, and has good economic and social benefits. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the standardized heating control system of this utility model.

[0014] Figure 2 This is a structural diagram of the control system of this utility model. Detailed Implementation

[0015] See Figure 1 and Figure 2This utility model mainly consists of a high-efficiency plate heat exchanger 1, a circulating water pump and frequency converter 2, a secondary pipeline water supply pipe temperature transmitter 3 and pressure transmitter 4, a secondary pipeline water return pipe temperature transmitter 5 and pressure transmitter 6, a field PLC controller 7, a secondary side electric regulating valve 8, a climate compensator 9, a primary side electric regulating valve 10, an online multi-functional ion passivation treatment device 11 (optional), a soft water tank and a level transmitter 12, etc., forming a standardized heating control system.

[0016] The primary side inlet and outlet of plate heat exchanger 1 are connected to the primary water supply pipe and the primary water return pipe of the pipeline network, respectively; a primary side electric regulating valve 10 is installed at the primary side outlet; the secondary side outlet and inlet of plate heat exchanger 1 are connected to the secondary water supply pipe and the secondary water return pipe of the pipeline network, respectively; a first temperature transmitter 3 and a first pressure transmitter 4 are installed on the secondary water supply pipe, and a second temperature transmitter 5 and a second pressure transmitter 6 are installed on the secondary water return pipe; the secondary water supply pipe and the secondary water return pipe are connected by a secondary side electric regulating valve 8; the soft water tank is replenished with water. The pump is connected to the secondary inlet of plate heat exchanger 1; a circulating water pump and a frequency converter for controlling the circulating water pump are installed between the secondary inlet of plate heat exchanger 1 and the secondary electric regulating valve 8; temperature transmitters 3 and 5, pressure transmitters 4 and 6, and level transmitter 12 are connected to the field PLC controller 7 via control lines using 4~20mA DC or RS485 signals; the field PLC controller 7 communicates with the climate compensator 9 using 4~20mA DC or RS485 signals or GPRS / 4G / 5G, NB-IoT wireless transmission. Equipment and components within the system can be purchased separately and supplied in a decentralized manner, or they can be assembled into skids and supplied as complete sets by the manufacturer. All equipment and components should meet or exceed the requirements of current national standards. Filters must be installed on both the primary and secondary inlet pipes of the plate heat exchanger to filter particles larger than 1mm, and drain valves must be installed.

[0017] This utility model's climate compensator generates a target value for the secondary hot water supply network's water temperature based on changes in outdoor temperature (from an air temperature sensor) and sends it to the on-site PLC controller. The on-site PLC controller obtains the actual secondary supply water temperature through a temperature transmitter installed on the secondary water supply pipeline, compares it with the received target temperature, and instructs the electric regulating valve of the primary hot water network to operate. By changing the flow rate of the primary hot water network through the heat exchanger, the heat supplied to users by the secondary hot water network is regulated. When the user system operates with variable flow (individual household control, users can set their own indoor temperature) or when there is hydraulic imbalance due to uneven heating in the secondary hot water network, the frequency converter communicates with the first pressure transmitter, the second pressure transmitter, and the secondary-side electric regulating valve through the on-site PLC controller. The secondary hot water network's circulating pump adapts to the system's flow rate changes through frequency conversion control based on the differential pressure value set by the on-site PLC controller. When the parallel-operated pumps are reduced to a single pump and the pump's operating frequency drops to the minimum safe operating frequency, the opening of the secondary-side electric regulating valve is adjusted to ensure safe and stable system operation.

[0018] The high-efficiency plate heat exchanger 1 has plates made of stainless steel with a thickness of not less than 0.5 mm, a heat transfer coefficient of ≥3500 W / m2.℃, a service life of ≥15 years, and the plates are not allowed to have any micro-cracks or other defects.

[0019] The circulating water pump and frequency converter 2 mentioned above: The hot water circulating pump should be able to deliver clean water at 80℃, use a frequency converter motor, and be equipped with a one-to-one frequency converter. The motor should be able to operate in accordance with the capacity of the water pump. The number of water pumps should be set as needed, all using frequency conversion regulation, and should not be less than two.

[0020] The temperature transmitters 3 and 4 of the secondary water supply pipe, and the temperature transmitters 5 and 6 of the secondary water return pipe, shall be intelligent integrated temperature transmitters based on microprocessors (brand level no lower than Rosemount, Vega, or Krohne), with excellent performance and stable reliability (stability should reach ±0.25% or 0.25°C reading error within five years, and its zero point and range should not be affected by the installation position after the transmitter module is installed). The pressure transmitters shall be intelligent pressure transmitters based on advanced sensor technology and microprocessors (brand level no lower than Rosemount, Vega, or Krohne), and their measurement principle should preferably be capacitive, with good temperature characteristics. The impact of changes in ambient temperature on its zero point and range should be better than ±(0.025% upper limit of range + 0.125% of range) for every 50°F (28°C) change in ambient temperature. The effect of a 1000 psi (6.9 MPa) change in static pressure should be better than ±0.1% of the upper limit of the range, and should have an overload capacity of 1.5 times the maximum range.

[0021] The aforementioned field PLC controller 7 (brand level no lower than Siemens S7-1200 series, AB1769 series, Schneider M300 series) should have main functions including, but not limited to, data acquisition, centralized monitoring and transmission, control, display, and data communication management. It should realize station communication connection through PLC programming and must have high reliability, stability, and flexibility to ensure safe and reliable production operation.

[0022] The secondary-side electric regulating valve 8 and the primary-side electric regulating valve 10 can monitor the supply and return water pressure and temperature in real time. By comparing the target value set by the cloud platform, the valve opening adjustment command is issued. The valve should have equal percentage flow characteristics and should not be a linear or fast-opening valve. The valve actuator adjustment accuracy should not be less than 2‰. The flow capacity KV and diameter of the valve must meet the process flow requirements.

[0023] When the outdoor climate changes, the temperature sensor installed on the outside of the building transmits the outdoor temperature information to the climate compensator. The climate compensator outputs an adjustment signal to the primary side electric regulating valve 10 according to the adjustment relationship curve under different conditions, automatically adjusting the primary side water supply flow and indirectly controlling the secondary side water supply temperature. Through quantitative adjustment control, the purpose of qualitative adjustment is achieved, which can overcome the indoor temperature fluctuation caused by changes in outdoor ambient temperature, resulting in energy saving and comfort.

[0024] The aforementioned online multifunctional ion passivation treatment device 11 (CCMMS) applies the principle of sacrificial anode protection in electrochemistry. The ions released by the chip assembly preferentially react with oxygen, forming a protective film on the metal tube wall. This inhibits iron oxidation, preventing rust formation and oxidative corrosion. The device can prevent carbonate crystal nuclei formation; decompose existing calcite carbonate scale; inhibit and kill algae; and remove residual chlorine and hydrogen sulfide, thus improving water quality.

[0025] The level transmitter 12 should be a sensitive transmitter (brand no lower than Rosemount, Vega, or Krohne). Its measurement principle should be based on continuous hydrostatic measurement of the liquid level in the container, converting the pressure signal into a level signal. After installation, its accuracy should be better than 0.1%, its stability for more than two years, and its annual cumulative drift should not exceed 100 Pa. The transmitter should have a local LCD indicator and a local adjustment function. The influence of changes in ambient temperature on its zero point and range should be less than ±(0.025% upper limit of range + 0.125% of range) for every 50°F (28℃) change in ambient temperature. When the static pressure changes between 0 and 13.7 MPa, the influence should be less than ±0.05% of the upper limit of range. Vibration influence: less than 0.1% for 15~2000Hz.

[0026] All transmitters should have self-diagnostic capabilities. Zero point and range adjustments should be possible using a dedicated handheld programmer, supporting the HART communication protocol. Signal resolution should be greater than 0.025%. Data update rate should be better than 200ms, adjustable range 20:1, and overload capacity greater than 1.5 times. Output signal should be 4–20mA DC (two-wire) and capable of outputting digital signals based on the HART communication protocol. Power supply should be 24VDC. After installation, the transmitter's zero point and range should be unaffected by its installation location, exhibiting no zero-point drift and requiring no recalibration.

[0027] Control requirements:

[0028] The climate compensator automatically adjusts the secondary side outlet water temperature setpoint according to changes in outdoor temperature, thus compensating for outdoor temperature variations. The climate compensator is located inside the plate heat exchanger control cabinet or in the central control room.

[0029] The on-site PLC controller adjusts the opening of the primary side electric regulating valve according to the secondary side outlet water temperature of the high-efficiency plate heat exchanger to maintain a constant supply water temperature.

[0030] The on-site PLC controller controls the variable frequency operation of the circulating pump based on the pressure difference between the secondary water supply and return, ensuring a constant pressure difference between the supply and return water.

[0031] When the pump operating frequency drops to the minimum safe operating frequency, and the supply and return water pressure difference is still higher than the set value, it indicates that the flow rate is still excessive. At this time, open and adjust the secondary side bypass electric regulating valve until the pressure difference set value can be guaranteed.

[0032] The on-site PLC controller automatically records the cumulative running time of each water pump and prioritizes starting the water pump with the shortest running time.

[0033] When the system pressure at the set point is lower than the set value, the circulating pump stops and an alarm sounds. When the water pressure rises to the set pressure, the circulating pump starts automatically.

[0034] The constant pressure water supply device must provide dry contacts for monitoring.

[0035] The softened water tank is equipped with a level sensor, and the opening and closing of the solenoid valve at the inlet of the water softener is controlled by a high / low level gauge. When the level is too low, the water supply pump shuts off.

Claims

1. A heat station control system suitable for central heating in the south, characterized by: It includes a plate heat exchanger, an on-site PLC controller, a primary side electric regulating valve, a secondary side electric regulating valve, a climate compensator and a soft water tank; the primary side inlet and the primary side outlet of the plate heat exchanger are respectively connected to the primary pipe network water supply pipe and the primary pipe network return pipe; the primary side electric regulating valve is arranged at the primary side outlet; the secondary side outlet and the secondary side inlet of the plate heat exchanger are respectively connected to the secondary pipe network water supply pipe and the secondary pipe network return pipe; the secondary pipe network water supply pipe is provided with a first temperature transmitter and a first pressure transmitter, and the secondary pipe network return pipe is provided with a second temperature transmitter and a second pressure transmitter; the secondary pipe network water supply pipe and the secondary pipe network return pipe are connected through the secondary side electric regulating valve; the soft water tank is connected to the secondary side inlet of the plate heat exchanger through a water supply pump; a circulating water pump and a frequency converter for controlling the circulating water pump are arranged between the secondary side inlet of the plate heat exchanger and the secondary side electric regulating valve; the temperature transmitter and the pressure transmitter are respectively connected to the on-site PLC controller through a control line; the on-site PLC controller and the climate compensator are connected by wireless transmission communication.

2. The heat station control system suitable for central heating in southern China as claimed in claim 1, characterized in that: An online multifunctional ion passivation treatment device is arranged between the secondary side electric regulating valve and the circulating water pump.

3. The heat station control system suitable for central heating in southern China as claimed in claim 1 or 2, characterized in that: Filters are installed at the primary inlet and the secondary inlet of the plate heat exchanger respectively.

4. The heat station control system suitable for central heating in southern China as claimed in claim 1 or 2, characterized in that: The plate heat exchanger has a heat transfer coefficient of ≥3500W / m 2 .℃ high-efficiency plate heat exchanger.

5. The heat station control system suitable for central heating in southern China as claimed in claim 1 or 2, characterized in that: The temperature transmitter is an intelligent integrated temperature transmitter containing a temperature sensor and a temperature transmitter; the pressure transmitter is an intelligent integrated pressure transmitter containing a pressure sensor and a pressure transmitter; a liquid level transmitter is provided in the soft water tank, and the liquid level transmitter is an intelligent integrated liquid level transmitter of a static pressure liquid level transmitter, a liquid level gauge and a liquid level transmitter; the temperature transmitter, the pressure transmitter and the liquid level transmitter are connected to the on-site PLC controller through a control line using 4~20mADC or RS485 signals respectively; the on-site PLC controller and the climate compensator communicate using 4~20mADC or RS485 signals or use GPRS / 4G / 5G, NB-LOT wireless transmission communication connection.

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