Distributed water temperature control method and system for a heating network

Abstract

The present application relates to the field of heat network operation control, and discloses a heat network distributed water temperature control method and system, the method comprising: controlling the water flow of each branch in the primary pipe network to be constant, determining the target temperature of the secondary pipe network on the user side according to the outdoor temperature; establishing a target function of the total heating cost, solving the target function according to the target temperature of the secondary pipe network to obtain an optimal solution, and obtaining the target temperature of the heat source point according to the optimal solution; using the valve controller of the heat source point to adjust the current temperature of the heat source point to the target temperature of the heat source point; the system comprises a secondary pipe network temperature calculation module, a target temperature calculation module and a control module. The present application can realize real-time scheduling and optimal utilization of all heat source points, and reduce the overall operation cost of the heat network.

Description

Technical Field

[0001] This invention relates to the field of heating network operation control technology, and in particular to a distributed water temperature control method and system for heating networks. Background Technology

[0002] Operation and control of heating networks are crucial for ensuring the quality, safety, stability, and economical operation of heating supply. Traditional heating networks use combined heat and power plants or boilers as centralized heat sources, with heat derived from the combustion of fossil fuels and delivered to end users via a tiered pipe network. However, these traditional heating networks generally suffer from drawbacks such as high carbon emissions, high energy consumption, and unsatisfactory comfort. To achieve peak carbon emissions and carbon neutrality, a clean and low-carbon centralized heating method is essential. In response to this issue, the international academic and industry community has proposed a fourth-generation heating network design concept, which includes the following characteristics:

[0003] First, fossil fuels are completely abandoned as heat sources, and replaced by various urban low-temperature heat sources, including clean energy sources such as industrial waste heat, solar energy, geothermal energy, wind energy, and bioenergy. Unlike traditional centralized heat sources, these heat sources are distributed.

[0004] Secondly, a low-temperature heating network replaces a high-temperature heating network. The use of a low-temperature medium in the heating network facilitates the transfer of heat from the low-temperature heat source to the heating network medium, thereby allowing the low-temperature heat source to be connected to the heating network system.

[0005] Thirdly, heat pumps are widely used in heating systems. Most heat pumps are installed at secondary stations or at the end of the heating network to improve the heat quality of the heat medium and then supply it to the end users. A small number of heat pumps are installed at the heat source end to enhance the heat transfer from the low-temperature heat source to the heat network medium.

[0006] The above characteristics bring new problems and challenges to the control of fourth-generation heating networks. The main problems and challenges are as follows: Fourth-generation heating networks contain many uncontrollable heat sources, such as industrial waste heat, whose heating capacity is constrained by enterprise production conditions. Other controllable heat sources, such as ground source heat pumps and water source heat pumps, are characterized by small individual adjustable heating capacities and dispersed geographical distribution. Simultaneously, to reduce the overall carbon emissions of the system, low-carbon and clean heat sources should be used as much as possible. Therefore, a new heating network operation control method must be proposed to ensure the safe and stable operation of fourth-generation heating networks.

[0007] Temperature regulation is currently the most commonly used method for controlling heating networks. This method primarily controls the heat supply by changing the temperature of the heat transfer medium while maintaining a constant flow rate. The advantages of this control method are stable hydraulic balance, ease of automated regulation of the heating network, and relatively safe system operation. Traditional multi-source heating networks mainly use a tracking dispatch curve for operation and control. The dispatch curve is a curve with outdoor temperature as the independent variable and network temperature as the dependent variable. Figure 1 The diagram shows the water temperature control curve for the pipe network. A schematic diagram of water temperature control at the heat source point is shown below. Figure 3 As shown, the primary pipeline network refers to the pipelines from the heat source plant of the centralized heating system to the valves at the inlet (interface) of each heat-consuming unit. The secondary pipeline network refers to the pipelines between individual buildings within each heat-consuming unit. During operation, the target water temperature of the pipeline network is first determined based on the outdoor temperature. Then, each heat source point in the heating network adjusts its heating supply according to the target water temperature and the actual water temperature to ensure that the actual water temperature matches the target water temperature.

[0008] In traditional heating networks, all heat sources operate according to a single set temperature, effectively treating all heat sources as equals. However, in the context of fourth-generation heating networks, using the same target temperature as traditional networks prevents the optimal utilization of various low-carbon heat sources. Furthermore, the heat pumps in secondary stations can maintain the target temperature in the secondary network through heating, so fluctuations in the primary network water temperature do not affect the user's heating experience. Moreover, the various low-carbon heat sources in the heating network are complex, potentially belonging to different industrial enterprises, users, investors, etc., and not all of them can accept real-time scheduling from the network's heat source providers. Therefore, it is difficult to adopt a global scheduling method to coordinate and manage all heat sources in real time. Summary of the Invention

[0009] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a distributed water temperature control method and system for heating networks, which can realize real-time scheduling and optimal utilization of all heat source points and reduce the overall operating cost of the heating network.

[0010] To solve the above technical problems, the present invention provides a distributed water temperature control method for heating networks, comprising:

[0011] Step 1: Keep the water flow rate of each branch in the primary pipeline constant, and determine the target temperature of the secondary pipeline on the user side based on the outdoor temperature;

[0012] Step 2: Establish the objective function for the total heating cost, solve the objective function based on the target temperature of the secondary pipe network to obtain the optimal solution, and obtain the target temperature of the heat source point based on the optimal solution;

[0013] Step 3: Use the valve controller at the heat source point to adjust the current temperature of the heat source point to the target temperature of the heat source point.

[0014] Preferably, the target temperature T of the secondary pipeline network s for:

[0015] T s =a·T e +T0,

[0016] Where a is the proportionality coefficient, T e This indicates the outdoor temperature, and T0 is the target temperature corresponding to an ambient temperature of 0℃.

[0017] Preferably, the objective function for the total heating cost is min C. total C total It is the total cost of heating, C total The calculation method is as follows:

[0018]

[0019] Where, q wh，i ε is the heat supplied by the i-th heat source point. wh，i q is the heating price of the i-th heat source, n is the number of heat sources, and q is the heating price of the ith heat source. e，j This is the electricity consumption of the j-th secondary station, ε e，j Let m be the electricity price of the j-th secondary power station, and m be the number of secondary power stations.

[0020] Preferably, the objective function is solved based on the target temperature of the secondary pipe network to obtain the optimal solution, and the target temperature of the heat source point is obtained based on the optimal solution, specifically as follows:

[0021] Establish q wh，i Regarding the average heat transfer temperature of the heat source medium at the i-th heat source point The average heat transfer temperature of the primary water supply network at the i-th heat source point The expression, to establish q e，j Regarding the water temperature T in the primary pipeline network p The expression;

[0022] Establish Regarding the outlet temperature T of the heat source medium at the i-th heat source point wh，out，i The expression, establish Regarding the return water temperature T of the primary pipeline network r The outlet water temperature T of the primary pipeline at the i-th heat source point p，i The expression, to establish T p Regarding the T p，i The expression;

[0023] Establish T wh，out，i Regarding the flow rate Q of the heat source medium at the i-th heat source point wh，i The expression, to establish Tr Regarding the T p，i The expression;

[0024] Establish and Q wh，i Given the constraints, the objective function is solved under these constraints to obtain T. p，i The optimal solution is to take the T p，i The optimal solution is taken as the target temperature of the heat source point.

[0025] Preferably, the q wh，i Regarding the average heat transfer temperature of the heat source medium at the i-th heat source point The average heat transfer temperature of the primary water supply network at the i-th heat source point The expression is:

[0026]

[0027] in, It is the average heat transfer temperature of the heat source medium at the i-th heat source point. It is the average heat transfer temperature of the primary water supply network at the i-th heat source point, K. i Q is the heat transfer coefficient of the i-th heat source point. p，i It is the primary water flow rate in the pipeline at the i-th heat source point;

[0028] The q e，j Regarding the water temperature T in the primary pipeline network p The expression is:

[0029]

[0030] Where, q user，j T is the heat load of the user corresponding to the j-th heat exchange station. s The target temperature of the secondary pipeline network, T p It is the water temperature of the primary pipeline network, η j It is the relative efficiency of the heat pump unit of the j-th secondary station.

[0031] Preferably, the Regarding the outlet temperature T of the heat source medium at the i-th heat source point wh，out，i The expression is:

[0032]

[0033] Among them, T wh，in，i T is the inlet temperature of the heat source medium at the i-th heat source point. wh，out，i It is the outlet temperature of the heat source medium at the i-th heat source point;

[0034] The Regarding the return water temperature T of the primary pipeline networkr The outlet water temperature T of the primary pipeline at the i-th heat source point p，i The expression is:

[0035]

[0036] Among them, T r It is the return water temperature of the primary pipeline network, T p，i It is the primary outlet water temperature of the pipeline at the i-th heat source point;

[0037] The T p Regarding the T p，i The expression is:

[0038]

[0039] Preferably, the T wh，out，i Regarding the flow rate Q of the heat source medium at the i-th heat source point wh，i The expression is:

[0040]

[0041] Among them, c wh，i Q is the specific heat capacity of the heat source medium at the i-th heat source point. wh，i It is the flow rate of the heat source medium at the i-th heat source point;

[0042] The T r Regarding the T p，i The expression is:

[0043]

[0044] Preferably, the and Q wh，i The constraints to be satisfied are:

[0045]

[0046] Q wh,i ≤Q wh,i,max i = 1, 2, ..., n;

[0047] Among them, Q wh,i,max It is the maximum flow rate of the heat source medium at the i-th heat source point.

[0048] This invention also provides a distributed water temperature control system for a heating network, including a secondary pipe network temperature calculation module, a target temperature calculation module, and a control module.

[0049] The secondary pipeline temperature calculation module determines the target temperature of the user-side secondary pipeline based on the outdoor temperature and transmits the target temperature of the secondary pipeline to the target temperature calculation module.

[0050] The target temperature calculation module establishes a target function for the total heating cost, solves the target function based on the target temperature of the secondary pipe network to obtain the optimal solution, obtains the target temperature of the heat source point based on the optimal solution, and transmits the target temperature of the heat source point to the control module.

[0051] The control module controls the water flow rate of each branch in the primary pipeline to remain constant, and uses the valve controller at the heat source point to adjust the current temperature of the heat source point to the target temperature of the heat source point.

[0052] Preferably, the valve controller at the heat source point is a PID controller with anti-integral saturation. The positive integral saturation state of the anti-integral saturation PID controller is when the valve is fully open, and the negative integral saturation state of the anti-integral saturation PID controller is when the valve is fully closed.

[0053] The technical solution of the present invention has the following advantages compared with the prior art:

[0054] This invention establishes an objective function for the total cost of heating and achieves real-time scheduling of all heat source points through a global scheduling method. At the same time, by inputting the heat from low-carbon heat sources into the heating network, the heat pumps of the secondary stations play a supplementary heating role, thereby maintaining the water temperature of the secondary pipeline network and achieving optimal utilization of various distributed low-carbon heat sources, thus reducing the overall operating cost of the heating network. Attached Figure Description

[0055] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0056] Figure 1 It is the water temperature control curve of the pipeline network.

[0057] Figure 2 This is a schematic diagram of water temperature control at the heat source point.

[0058] Figure 3 This is a schematic diagram of a typical fourth-generation heating system.

[0059] Figure 4 This is a schematic diagram of the heating pipe network in an embodiment of the present invention.

[0060] Figure 5 This is a flowchart of the present invention.

[0061] Figure 6 The target temperature T of the secondary pipeline network in this embodiment of the invention is s The curve showing the change. Detailed Implementation

[0062] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0063] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "second" or "first" may explicitly or implicitly include one or more of that feature. In the description of this invention, "many" means two or more, unless otherwise explicitly specified. Furthermore, the term "comprising" is intended to cover a non-exclusive inclusion, such as a process, method, system, product, or apparatus that includes a series of steps or units, not limited to the listed steps or units but optionally including steps or units not listed, or optionally including other steps or units inherent to such processes, methods, products, or apparatus.

[0064] This invention relates to a distributed water temperature control method for fourth-generation heating systems, such as... Figure 3 The diagram shows a typical fourth-generation heating system. It includes a primary pipeline network, several heat source points, several secondary stations, and corresponding user-side secondary pipeline networks. At each heat source point, the heat source medium exchanges heat with the water in the primary pipeline network through a heat exchanger, thereby inputting heat into the network. The water in the primary pipeline network at each heat source point is collected and flows to the user-side secondary stations. Each secondary station is equipped with a heat pump, which uses the water in the primary pipeline network as a heat source to heat the return water in the secondary pipeline network. The water outlet of the secondary pipeline network is then directed to the user terminal, delivering heat to the user. The return water from the primary pipeline network at each secondary station is collected and flows back to the respective heat source points.

[0065] In this embodiment, as shown in... Figure 4 Water temperature control is performed under the heating network shown. Without loss of generality, Figure 4 The heating network shown considers a network containing two heat source points (heat source point 1 and heat source point 2) and one secondary station (secondary station 1), as shown in the figure. Figure 5 As shown in the flowchart, this invention discloses a distributed water temperature control method for a heating network, comprising the following steps:

[0066] Step 1: Use quality regulation, i.e., control the water flow rate of each branch in the primary pipeline network to remain constant, and determine the target temperature T of the secondary pipeline network on the user side based on the outdoor temperature. s for:

[0067] T s =a·T e +T0,

[0068] Where a is the proportionality coefficient, T eThe outdoor temperature is represented by T0, which is the target temperature corresponding to an ambient temperature of 0°C. In this embodiment, the target temperature T of the secondary pipe network is... s The curve is as follows Figure 6 As shown, a = 1, T0 = 45, T e =5℃, T s =40℃.

[0069] Step 2: Establish the objective function for the total heating cost, solve the objective function based on the target temperature of the secondary pipe network to obtain the optimal solution, and obtain the target temperature of the heat source point based on the optimal solution.

[0070] Step 2-1: Establish the objective function for the total heating cost as min C total C total It is the total cost of heating, C total The calculation method is as follows:

[0071]

[0072] Where, q wh，i ε is the heat supplied by the i-th heat source point. wh，i q is the heating price of the i-th heat source, n is the number of heat sources, and q is the heating price of the ith heat source. e，j This is the electricity consumption of the j-th secondary station, ε e，j is the electricity price of the j-th secondary power station, and m is the number of secondary power stations. In this embodiment, the corresponding... Figure 4 n = 2, m = 1.

[0073] Step 2-2: Solve the objective function based on the target temperature of the secondary pipe network to obtain the optimal solution, and obtain the target temperature of the heat source point based on the optimal solution, specifically as follows:

[0074] Step 2-2-1: C total ε wh，i ε e，j As a known variable, in this embodiment, ε wh，1 =3×10 -5 Yuan / kJ, ε wh，2 =10 -5 Yuan / kJ, ε e，1 =2.22×10 -4 Yuan / kJ; The optimal solution is required, i.e., the solution C is required. total The smallest q wh，i and q e，j Therefore, q is established. wh，i and q e，j The expression.

[0075] Establish q wh，i Regarding the average heat transfer temperature of the heat source medium at the i-th heat source point The average heat transfer temperature of the primary water supply network at the i-th heat source point The expression:

[0076]

[0077] in, It is the average heat transfer temperature of the heat source medium at the i-th heat source point. It is the average heat transfer temperature of the primary water supply network at the i-th heat source point, K. i Q is the heat transfer coefficient of the i-th heat source point. p，i It is the primary water flow rate in the pipeline at the i-th heat source point;

[0078] Establish q e，j Regarding the water temperature T in the primary pipeline network p The expression:

[0079]

[0080] Where, q user，j T is the heat load of the user corresponding to the j-th heat exchange station. s The target temperature of the secondary pipeline network, T p It is the water temperature of the primary pipeline network, η j It is the relative efficiency of the heat pump unit of the j-th secondary station;

[0081] Step 2-2-2: q wh，j and q e，j China Q p，i q user，j T s η j K i It is known that, in this embodiment, Q p，1 =Q p，2 =1000kg / s, q user，j =63000kJ / s, T s =40℃, η1 = 50%, K1 = K2 = 2.8 kJ / (℃·s); Solve for q. wh，i and q e，j That is, to solve and T p Therefore, establish T p The expression:

[0082] Establish Regarding the outlet temperature T of the heat source medium at the i-th heat source point wh，out，i The expression is:

[0083]

[0084] Among them, T wh，in，iT is the inlet temperature of the heat source medium at the i-th heat source point. wh，out，i It is the outlet temperature of the heat source medium at the i-th heat source point;

[0085] Establish Regarding the return water temperature T of the primary pipeline network r The outlet water temperature T of the primary pipeline at the i-th heat source point p，i The expression is:

[0086]

[0087] Among them, T r It is the return water temperature of the primary pipeline network, T p，i It is the primary outlet water temperature of the pipeline at the i-th heat source point;

[0088] Establish T p Regarding the primary pipeline outlet water temperature T at the i-th heat source point p，i The expression is:

[0089]

[0090] Step 2-2-3: T p China T wh，in，i It is known that, in this embodiment, T wh，in，1 =50℃, T wh，in，2 =40℃; Solve T p That is, to solve T wh，out，i T r T p，i Therefore, T is established. wh，out，i T r T p，i The expression:

[0091] Establish T wh，out，i Regarding the flow rate Q of the heat source medium at the i-th heat source point wh，i The expression is:

[0092]

[0093] Among them, c wh，i Q is the specific heat capacity of the heat source medium at the i-th heat source point. wh，i It is the flow rate of the heat source medium at the i-th heat source point;

[0094] Establish T r Regarding the primary pipeline outlet water temperature T at the i-th heat source point p，i The expression is:

[0095]

[0096] Step 2-2-4: T wh，out，i T r c wh，i It is known that, in this embodiment, c wh，1 =c wh，2 = 4.2 kJ / kg℃; that is, we still need to solve for Q. wh，i T p，i

[0097] Establish and Q wh，i The constraints to be satisfied are:

[0098]

[0099] Q wh，i ≤Q wh，imax i = 1, 2, ..., n;

[0100] Among them, Q wh，i，max Q is the maximum flow rate of the heat source medium at the i-th heat source point. wh，i，max As a known variable, Q in this embodiment wh，1，max =Q wh，2，max =2000 kg / s.

[0101] Solving the objective function under the given constraints, only T remains. p，i This variable to be optimized can be found in C. total When T is minimized p，i The optimal solution is found in this embodiment, where all variables are in their corresponding International System of Units (SI).

[0102] Step 2-2-5: Place T p，i The optimal solution is taken as the target temperature of the heat source point.

[0103] The specific process for solving the optimization problem in this embodiment is as follows:

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117] Q wh,1 ≤Q wh,1,max Q wh,2 ≤Q wh,2,max

[0118] Therefore, the solution is T. p,1 =40℃,T p,2 =35℃, at which point the total heating cost C total =3.21 yuan / s.

[0119] Step 3: Use the valve controller at the heat source point to adjust the current temperature of the heat source point to the target temperature of the heat source point, and effectively control the temperature of each heat source point.

[0120] Under the same conditions, experiments were conducted using the traditional operating mode of a heating network, where the target temperature of all heat sources was set to 40℃. In this case, T... p,1 =40℃,T p,2 =40℃, under traditional circumstances, the total heating cost C total =3.59 yuan / s. This is because when the target temperature of the pipeline network rises, the amount of heat input from the low-temperature heat source decreases, requiring more energy from electricity, which is much more expensive than the low-temperature heat source. Clearly, by adopting this invention, the cost is lower than that of traditional solutions, demonstrating the superiority of this invention.

[0121] This invention also discloses a distributed water temperature control system for a heating network, including a secondary network temperature calculation module, a target temperature calculation module, and a control module. The secondary network temperature calculation module determines the target temperature of the user-side secondary network based on the outdoor temperature and transmits this target temperature to the target temperature calculation module. The target temperature calculation module establishes a target function for the total heating cost, solves the target function based on the target temperature of the secondary network to obtain the optimal solution, obtains the target temperature of the heat source point based on the optimal solution, and transmits the target temperature of the heat source point to the control module. The control module maintains a constant water flow rate in each branch of the primary network and uses a valve controller at the heat source point to adjust the current temperature of the heat source point to the target temperature. The valve controller at the heat source point is an anti-integral saturation PID controller; the positive integral saturation state of the anti-integral saturation PID controller is a fully open valve, and the negative integral saturation state is a fully closed valve.

[0122] In the context of fourth-generation heating networks, traditional quality control methods based on a single temperature dispatch curve prevent the priority utilization of various low-carbon heat sources. Instead, these sources may be used for heat transfer due to their lower temperatures compared to coal-fired boilers. Furthermore, the entities responsible for these low-carbon heat sources in fourth-generation heating networks are complex, potentially belonging to different industrial enterprises, users, and investors. Not all of these entities can receive real-time dispatch from the network's heat source providers, making a global dispatch method ineffective for real-time coordination of all heat source points. This invention establishes an objective function regarding the total heating cost and achieves real-time dispatch of all heat source points through a global dispatch method. Simultaneously, by inputting heat from low-carbon heat sources into the heating network, the heat pumps at secondary stations supplement the heating supply, maintaining the secondary network's water temperature without requiring real-time communication. This optimizes the utilization of various distributed low-carbon heat sources, thereby reducing the overall operating cost of the heating network.

[0123] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0124] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0125] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0126] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0127] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for distributed water temperature control in a heating network, characterized in that, include: Step 1: Keep the water flow rate of each branch in the primary pipeline constant, and determine the target temperature of the secondary pipeline on the user side based on the outdoor temperature; Step 2: Establish the objective function for the total heating cost, solve the objective function based on the target temperature of the secondary pipe network to obtain the optimal solution, and obtain the target temperature of the heat source point based on the optimal solution; The objective function for the total heating cost is: ,in It is the total cost of heating. The calculation method is as follows: ， in, It is the heat supply of the i-th heat source point. Here, n is the heating price for the i-th heat source, and n is the number of heat sources. This is the electricity consumption of the j-th secondary station. Let m be the electricity price of the j-th secondary power station, and m be the number of secondary power stations. The objective function is solved based on the target temperature of the secondary pipe network to obtain the optimal solution. The target temperature of the heat source point is then obtained based on the optimal solution. Specifically: Establish Regarding the average heat transfer temperature of the heat source medium at the i-th heat source point The average heat transfer temperature of the primary network water at the i-th heat source point The expression is: ； in, It is the average heat transfer temperature of the heat source medium at the i-th heat source point. It is the average heat transfer temperature of the primary water supply network at the i-th heat source point. It is the heat transfer coefficient of the i-th heat source point. It is the primary water flow rate in the pipeline at the i-th heat source point; Establish Regarding the water temperature of the primary pipeline network The expression; establish Regarding the outlet temperature of the heat source medium at the i-th heat source point The expression, establish Regarding the return water temperature of the primary pipeline network The outlet water temperature of the primary pipeline at the i-th heat source point The expression, establish Regarding the above The expression; Establish Regarding the flow rate of the heat source medium at the i-th heat source point The expression is: ； in, It is the specific heat capacity of the heat source medium at the i-th heat source point. It is the flow rate of the heat source medium at the i-th heat source point. It is the inlet temperature of the heat source medium at the i-th heat source point; Establish Regarding the above The expression is: ， in, It is the heat load of the user corresponding to the j-th heat exchange station; Establish and The objective function is obtained by solving the constraints that are satisfied under the given constraints. The optimal solution is to... The optimal solution is taken as the target temperature of the heat source point; Step 3: Use the valve controller at the heat source point to adjust the current temperature of the heat source point to the target temperature of the heat source point.

2. The distributed water temperature control method for heating networks according to claim 1, characterized in that: The target temperature of the secondary pipeline network for: ， Where 'a' is the proportionality coefficient. This indicates the outdoor temperature, and T0 is the target temperature corresponding to an ambient temperature of 0℃.

3. The distributed water temperature control method for heating networks according to claim 1, characterized in that: The Regarding the water temperature of the primary pipeline network The expression is: ； in, It is the heat load of the user corresponding to the j-th heat exchange station. This is the target temperature of the secondary pipeline network. It is the water temperature of the pipeline network. It is the relative efficiency of the heat pump unit of the j-th secondary station.

4. The distributed water temperature control method for heating networks according to claim 3, characterized in that: The Regarding the outlet temperature of the heat source medium at the i-th heat source point The expression is: ； in, It is the inlet temperature of the heat source medium at the i-th heat source point. It is the outlet temperature of the heat source medium at the i-th heat source point; The Regarding the return water temperature of the primary pipeline network The outlet water temperature of the primary pipeline at the i-th heat source point The expression is: ； in, It is the return water temperature of the primary pipeline network. It is the primary outlet water temperature of the pipeline at the i-th heat source point; The Regarding the above The expression is: 。 5. The distributed water temperature control method for heating networks according to claim 1, characterized in that: The and The constraints to be satisfied are: ， ； in, It is the maximum flow rate of the heat source medium at the i-th heat source point.

6. A distributed water temperature control system for a heating network, characterized in that: It includes a secondary pipeline temperature calculation module, a target temperature calculation module, and a control module. The secondary pipeline temperature calculation module determines the target temperature of the user-side secondary pipeline based on the outdoor temperature and transmits the target temperature of the secondary pipeline to the target temperature calculation module. The target temperature calculation module establishes a target function for the total heating cost, solves the target function based on the target temperature of the secondary pipe network to obtain the optimal solution, obtains the target temperature of the heat source point based on the optimal solution, and transmits the target temperature of the heat source point to the control module. The objective function for the total heating cost is: ,in It is the total cost of heating. The calculation method is as follows: ， in, It is the heat supply of the i-th heat source point. Here, n is the heating price for the i-th heat source, and n is the number of heat sources. This is the electricity consumption of the j-th secondary station. Let m be the electricity price of the j-th secondary power station, and m be the number of secondary power stations. The objective function is solved based on the target temperature of the secondary pipe network to obtain the optimal solution. The target temperature of the heat source point is then obtained based on the optimal solution. Specifically: Establish Regarding the average heat transfer temperature of the heat source medium at the i-th heat source point The average heat transfer temperature of the primary network water at the i-th heat source point The expression is: ； in, It is the average heat transfer temperature of the heat source medium at the i-th heat source point. It is the average heat transfer temperature of the primary water supply network at the i-th heat source point. It is the heat transfer coefficient of the i-th heat source point. It is the primary water flow rate in the pipeline at the i-th heat source point; Establish Regarding the water temperature of the primary pipeline network The expression; Establish Regarding the outlet temperature of the heat source medium at the i-th heat source point The expression, establish Regarding the return water temperature of the primary pipeline network The outlet water temperature of the primary pipeline at the i-th heat source point The expression, establish Regarding the above The expression; Establish Regarding the flow rate of the heat source medium at the i-th heat source point The expression is: ； in, It is the specific heat capacity of the heat source medium at the i-th heat source point. It is the flow rate of the heat source medium at the i-th heat source point. It is the inlet temperature of the heat source medium at the i-th heat source point; Establish Regarding the above The expression is: ， in, It is the heat load of the user corresponding to the j-th heat exchange station; Establish and The objective function is obtained by solving the constraints that are satisfied under the given constraints. The optimal solution is to... The optimal solution is taken as the target temperature of the heat source point; The control module controls the water flow rate of each branch in the primary pipeline to remain constant, and uses the valve controller at the heat source point to adjust the current temperature of the heat source point to the target temperature of the heat source point.

7. The distributed water temperature control system for heating networks according to claim 6, characterized in that: The valve controller at the heat source point is a PID controller with anti-integral saturation. The positive integral saturation state of the anti-integral saturation PID controller is when the valve is fully open, and the negative integral saturation state of the anti-integral saturation PID controller is when the valve is fully closed.

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