Intelligent control method for multi-stage heat supply system

Abstract

The invention provides an intelligent control method for a multi-stage heat supply system. The intelligent control method comprises the following steps that the opening degree of each user pipe network flow valve is adjusted based on a closed-loop feedback control strategy; the heat supply water flow of a main pipeline is adjusted based on the tail end pressure difference of each secondary pipe network and the statistical characteristics of the opening degree of a flow valve; the heat supply water flow of the main pipeline is adjusted based on the heat profit and loss state of the second-stage pipe network included in each first-stage pipe network and the opening characteristic of the flow valve; and the heating degree of the heat supply water of the system is adjusted based on the heat profit and loss state of the secondary pipe network for heat supply of each heat supply source. According to the intelligent control method provided by the invention, the heat supply system is intelligently controlled efficiently and safely in a step-by-step self-adaptive adjustment mode from bottom to top.

Description

Technical Field

[0001] This application belongs to the technical field of intelligent control of heating systems. Specifically, it relates to an intelligent control method for a multi-stage heating system. Background Art

[0002] A heating system composed of multi-stage heating pipe networks in a cascaded manner can better meet the heating demands of a large number of users in a large area. However, with the expansion of the scale of the heating pipe network and the increase in the complexity of the cascaded structure, the difficulty of reasonably distributing the heat in the multi-stage heating pipe network will also increase rapidly.

[0003] Currently, the existing control methods for multi-stage heating systems mostly adopt a top-down control method: data such as the indoor temperature and actual heating demand of each terminal user are continuously fed back to the central control system. The central control system estimates the heat load demand of the entire system based on a pre-established heating model or a pre-trained deep learning model, and uses the estimation result of the heat load demand as the adjustment basis to determine the adjustment amounts of the heating water flow rate and temperature of each level of pipe network, so as to achieve the step-by-step adjustment of the heat distribution in the system.

[0004] However, the above existing technical solutions for top-down step-by-step regulation of multi-stage heating systems have at least the following insurmountable problems: First, due to the limitations of actual conditions, it is actually impossible to accurately collect the actual heating status of each terminal user. Therefore, all existing heat load estimation algorithms and models cannot obtain accurate estimation results. Second, the existing various intelligent control methods focus on meeting the heating demands of each independent terminal user, and do not consider the influence of the distribution characteristics of the flow valve openings of a large number of terminal users on the overall energy consumption and safety of the system. In addition, the adjustment of the flow rate and temperature by the control center according to the end heat load demand needs to be transmitted step by step from the main pipe and branch pipes to the terminal users, and new adjustment amounts need to be generated according to the feedback results after being transmitted to the terminal users. Due to the hysteresis of the flow and temperature changes of the heating water, the adjustment is constantly misaligned with the actual changes, which is likely to cause "oscillation" of the flow rate and temperature in the pipe network, not only increasing energy consumption and operation risks, but also affecting the heating stability and comfort of terminal users. Summary of the Invention

[0005] In order to solve the deficiencies of the existing heating system control methods described above, this application provides an intelligent control method for a multi-stage heating system through embodiments, which is used to control a multi-stage heating system composed of a heat source, a primary pipe network, a secondary pipe network, and a user pipe network in cascade. The method includes the following operations:

[0006] For each user pipe network, adjust the opening of its flow valve based on a closed-loop feedback control strategy;

[0007] For each secondary pipe network, based on the pressure difference at its end and the statistical characteristics of the flow valve openings of each user pipe network it includes, adjust the heating water flow rate of its main pipeline;

[0008] For each primary pipe network, based on the heat profit and loss status of each secondary pipe network it includes, and the statistical characteristics of the flow valve openings of each user pipe network it includes, adjust the heating water flow rate of its main pipeline;

[0009] For each heat source, based on the heat profit and loss status of each secondary pipe network heated by it, adjust the heating degree of the heating water for the multi-stage heating system.

[0010] Further, by cyclically executing the following steps, adjust the opening degree of the flow valve of the user pipe network:

[0011] Step S31, obtain the user room temperature where the user pipe network is located;

[0012] Step S32, determine whether the user room temperature has achieved a preset room temperature adjustment target. If the determination result is no, execute step S33. If the determination result is yes, execute step S34;

[0013] Step S33, adjust the opening degree of the flow valve to move the user room temperature towards the room temperature adjustment target, and then return to step S31;

[0014] Step S34, determine whether the opening degree of the flow valve is within the optimal opening degree range. If the determination result is yes, execute step S35. If the determination result is no, execute step S36;

[0015] Step S35, maintain the opening degree of the flow valve, and then return to step S31;

[0016] Step S36, adjust the opening degree of the flow valve to move the opening degree of the flow valve towards the optimal opening degree range, and then return to step S31.

[0017] Preferably, the median value of the optimal opening degree range is greater than 50%.

[0018] Preferably, the median value of the optimal opening degree range is positively correlated with the distance from the user pipe network to the inlet of its upper-level secondary pipe network.

[0019] Further, by cyclically executing the following steps, adjust the heating water flow rate of the main pipeline of the secondary pipe network:

[0020] Step S21: Obtain the end differential pressure of the secondary pipeline network and the statistical characteristics of the flow valve openings of each user pipeline network included in the secondary pipeline network. The statistical characteristics of the flow valve openings include: the proportion of flow valves with valve openings less than, within, and greater than the optimal opening range.

[0021] Step S22: Determine whether the end differential pressure is lower than the safe differential pressure range. If the determination result is yes, increase the heating water flow rate of the main pipeline of the secondary pipeline network, and then return to Step S21. If the determination result is no, execute Step S23.

[0022] Step S23: Determine whether the proportion of flow valves with valve openings within the optimal opening range exceeds the first proportion threshold. If the determination result is yes, maintain the heating water flow rate of the main pipeline of the secondary pipeline network and return to Step S21. If the determination result is no, execute Step S24.

[0023] Step S24: Determine whether the proportion of flow valves with valve openings less than the optimal opening range exceeds the second proportion threshold. If the determination result is yes, reduce the heating water flow rate of the main pipeline of the secondary pipeline network, and then return to Step S21. If the determination result is no, execute Step S25.

[0024] Step S25: Determine whether the proportion of flow valves with valve openings greater than the optimal opening range exceeds the third proportion threshold. If the determination result is yes, increase the heating water flow rate of the main pipeline of the secondary pipeline network, and then return to Step S21. If the determination result is no, execute Step S26.

[0025] Step S26: Adjust the heating water flow rate of the main pipeline of the secondary pipeline network to increase the proportion of flow valves with valve openings within the optimal opening range in the secondary pipeline network, and then return to Step S21.

[0026] Preferably, the lower limit of the safe differential pressure range is 0.015 MPa to 0.02 MPa.

[0027] Preferably, the first proportion threshold is greater than or equal to the second proportion threshold; the second proportion threshold is greater than or equal to the third proportion threshold.

[0028] Furthermore, by cyclically executing the following steps, adjust the heating water flow rate of the main pipeline of the primary pipeline network:

[0029] Step S11: Obtain and count the heat profit and loss status of each secondary pipeline network included in the primary pipeline network. The heat profit and loss status includes a heat surplus status and a heat loss status.

[0030] Step S12: Determine whether there is a secondary pipe network in the primary pipe network that is in a heat deficit state. If the determination result is yes, increase the heating water flow rate of the main pipeline of the primary pipe network, and then return to Step S11. If the determination result is no, execute Step S13;

[0031] Step S13: Adjust the heating water flow rate of the main pipeline of the primary pipe network to increase the proportion of flow valves with valve openings in the optimal opening range in the downstream user pipe network, and then return to Step S11.

[0032] Furthermore, by cyclically executing the following steps, adjust the heating degree of the heating water in the system by the heat supply source:

[0033] Step S41: Obtain and count the heat profit and loss status of each secondary pipe network heated by the heat supply source, where the heat profit and loss status includes a heat surplus state and a heat deficit state;

[0034] Step S42: Determine whether there is a secondary pipe network in a heat deficit state among the secondary pipe networks heated by the heat supply source. If the determination result is yes, increase the temperature of the heating water heated by the heat supply source, and then return to Step S41. If the determination result is no, execute Step S43;

[0035] Step S43: Determine whether there is a secondary pipe network in a heat surplus state among the secondary pipe networks heated by the heat supply source. If the determination result is yes, execute Step S44. If the determination result is no, directly return to Step S41;

[0036] Step S44: Determine whether the proportion of secondary pipe networks in a heat surplus state exceeds the fourth proportion threshold. If the determination result is yes, decrease the temperature of the heating water heated by the heat supply source, and then return to Step S41. If the determination result is no, directly return to Step S41.

[0037] Specifically, when the end differential pressure of the secondary pipe network is not in the safe differential pressure range and the proportion of flow valves with valve openings smaller than the optimal opening range in the secondary pipe network exceeds the second proportion threshold, the secondary pipe network is in a heat surplus state; when the proportion of flow valves with valve openings larger than the optimal opening range in the secondary pipe network exceeds the third proportion threshold, the secondary pipe network is in a heat deficit state.

[0038] An intelligent control method for a multi - level heating system provided by an embodiment of the present application has at least the following beneficial effects: By adopting a bottom - up step - by - step adaptive control method, for the terminal user pipe network, based on the closed - loop feedback control strategy, the opening degree of its flow valve is adjusted to move towards an ideal valve opening degree range on the basis of meeting the heating demand of users; for the secondary pipe network, flow regulation is carried out according to the statistical characteristics of the opening degrees of the flow valves of each terminal user, taking into account the need for efficient heat distribution in the pipe network and the safe operation of the system; for the primary pipe network and the heat source, flow and water temperature regulation are respectively carried out based on the heat profit and loss states of each secondary pipe network. By setting different monitoring parameters and regulation indexes for each level of heating pipe network, the problems existing in the top - down step - by - step regulation framework in the current large - scale heating pipe network control technology, such as the too slow regulation process and the inability to accurately obtain the terminal heat load demand, are effectively solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1A It is a schematic diagram of the architecture of a multi - level heating system;

[0040] Figure 1B is Figure 1A a schematic diagram of the structure of the user pipe network in

[0041] Figure 2 It is a flowchart of a method for controlling a multi - level heating system from top to bottom in the prior art;

[0042] Figure 3 It is a schematic diagram of the actual indoor heating states of multiple terminal users with the same indoor house type in some embodiments;

[0043] Figure 4 It is a schematic diagram of the intelligent control method for the multi - level heating system provided by the embodiment of the present application;

[0044] Figure 5 It is a flowchart of adjusting the opening degree of the flow valve of the user pipe network provided by the embodiment of the present application;

[0045] Figure 6 It is a flowchart of adjusting the heating water flow of the main pipeline of the secondary pipe network provided by the embodiment of the present application;

[0046] Figure 7A It is a schematic diagram of the opening degree distribution of each flow valve in the secondary pipe network in a specific embodiment;

[0047] Figure 7B It is a schematic diagram of the opening degree distribution of each flow valve in the secondary pipe network in another specific embodiment;

[0048] Figure 7CIn another specific embodiment, it is a schematic diagram of the opening degree distribution of each flow valve in the secondary pipe network;

[0049] Figure 7D In another specific embodiment, it is a schematic diagram of the opening degree distribution of each flow valve in the secondary pipe network;

[0050] Figure 8 It is a flowchart for adjusting the heating water flow rate of the main pipeline of the primary pipe network according to the embodiment of the present application;

[0051] Figure 9 It is a flowchart for adjusting the heating degree of the heating water in the system by the heat source according to the embodiment of the present application;

[0052] Figure 10 It is a flowchart for adjusting the heating water flow rate of the main pipeline of the primary pipe network according to the embodiment of the present application. Specific embodiments

[0053] Hereinafter, the present application will be further described based on the preferred embodiments with reference to the drawings.

[0054] In the description of the embodiments of the present application, it should be noted that if terms such as "upper", "lower", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the products in the embodiments of the present application are usually placed during use. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to the present application. In addition, in the description of the present application, in order to distinguish different units, the terms "first", "second", etc. are used in this specification, but these are not restricted by the manufacturing order and cannot be understood as indicating or implying relative importance. On the detailed description and claims of the present application, their names may be different. In addition, for the convenience of understanding, various components in the drawings are enlarged or reduced, but this approach is not to limit the protection scope of the present application.

[0055] The terms used in this specification are for the purpose of describing the embodiments of the present application, but are not intended to limit the present application. It should also be noted that unless otherwise clearly defined and limited, if terms such as "set", "connected", "connected" are used, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be specifically understood.

[0056] Figure 1AIt is a schematic framework diagram of a multi - stage heating system formed in a cascaded manner. This multi - stage heating system can provide heating services to a large number of end - users within a large range. For example, Figure 1A As shown, the heating system includes at least one heat source 4 from top to bottom, at least one primary pipe network 1 heated by the heat source 4, at least one secondary pipe network 2 located at the lower level of the primary pipe network 1, and several user pipe networks located at the lower level of the secondary pipe network 2. Among them, the main pipeline of each primary pipe network 1 is composed of a primary main supply pipe 11 and a primary main return pipe 12. The above - mentioned main pipelines are respectively connected to each secondary pipe network 2 at the lower level through multiple branch pipelines; similarly, the main pipeline of each secondary pipe network 2 is composed of a secondary main supply pipe 21 and a secondary main return pipe 22. The above - mentioned main pipelines are respectively connected to each user pipe network 3 at the lower level through multiple branch pipelines.

[0057] Figure 1B It is Figure 1A a schematic diagram of the specific structure of the user pipe network 3 in Figure 1B As shown, each user pipe network 3 includes a terminal inlet pipe 31, a terminal outlet pipe 32, and terminal heating devices 33 such as radiators and floor heating equipment in the indoor of the end - user. One end of the terminal inlet pipe 31 and the terminal outlet pipe 32 enters the indoor of the end - user and is connected to the terminal heating device 33, and the other end is connected to the secondary pipe network 2 at its upper level. Through this cascaded method, the heating water heated by the heat source 4 flows downward step by step from the primary main supply pipe 11 of the primary pipe network 1 to each terminal heating device 33, exchanges heat with the indoor air, and then flows upward step by step back to the primary main return pipe 12 of the primary pipe network 1 and is heated by the heat source 4 again.

[0058] In order to achieve the regulation of the flow rate of the heating water in each level of the pipe network, as Figure 1A , Figure 1B shown, the primary pipe network 1 also includes a primary circulation pump 13 and a primary control unit 14. The primary circulation pump 13 is arranged on the main pipeline of the primary pipe network 1 (such as on the primary main supply pipe 11 or the primary main return pipe 12), and can regulate the flow rate of the heating water in the main pipeline of the primary pipe network 1 under the control of the primary control unit 14; the secondary pipe network 2 also includes a secondary circulation pump 23 and a secondary control unit 24. The secondary circulation pump 23 is arranged on the main pipeline of the secondary pipe network 2 (such as on the secondary main supply pipe 21 or the secondary main return pipe 22), and can regulate the flow rate of the heating water in the main pipeline of the secondary pipe network 2 under the control of the secondary control unit 24; the user pipe network 3 also includes a flow valve 34 and a terminal control unit 35. The flow valve 34 is arranged on the terminal inlet pipe 31 of the user pipe network 3 (or on the terminal outlet pipe 32), and can regulate the flow rate of the heating water flowing through the terminal heating device 33 under the control of the terminal control unit 35.

[0059] The heat supply source 4 can be a device for heating heating water known to those skilled in the art, such as a boiler room, a large heat pump, or a district energy center, a large heat exchange station, etc. Through the heat exchanger device 41 therein, heat exchange can be achieved between the high-temperature heating water heated by the boiler or flowing in from the upper level of the heat exchange station and the heating water provided to the end users (generally, the side where the high-temperature heating water circulates is called the primary network side, and the side where the heating water circulates is called the secondary network side). In order to adjust the heating degree of the heating water in the system, such as Figure 1A as shown, the heat supply source 4 further includes a water temperature control unit 42. Through the water temperature control unit 42, the heating degree of the boiler for the high-temperature heating water can be controlled, or the flow rate of the high-temperature heating water can be adjusted, so as to adjust the heating degree of the heating water in the multi-stage heating system (i.e., the water temperature of the heating water flowing out of the primary main supply pipe 11).

[0060] Figure 2 shows an existing control method for a heating system. This control method controls the multi-stage heating system shown in Figure 1A and Figure 1B in a top-down control manner. As Figure 2 shown, the central control system located at the upper layer calculates the heat demand of each level of pipe network in the system according to the indoor temperature of each end user collected and the temperature set by the user, combined with information such as the indoor area of the user, using a pre-established heat load demand prediction model (including an analytical model or a trained deep learning model, etc.), and then adjusts the temperature of the heating water and the flow rate of the heating water in each level of pipe network according to the demand. The above adjustments of the flow rate and temperature will be transmitted from the upper-level pipe network to the user pipe networks corresponding to each end user level by level from top to bottom. As the adjustment progresses, new indoor temperature and other information are continuously fed back to the central control system, thus completing the closed-loop control of the multi-stage heating system. In addition, in order to achieve more accurate heating, steps can also be added to correct the prediction results of the heat load demand according to weather forecast information or information such as the measured heat loss of the pipe network.

[0061] During the actual heating process of the multi-stage heating system by the applicant, it is found that the above top-down heat adjustment control method has the following insurmountable problems:

[0062] (1) First of all, the effect of the above adjustment scheme depends to a large extent on the accuracy of predicting the heat load demand of the system. However, during the actual heating process of the heating pipe network for users, due to the limitations of actual conditions, it is actually impossible to accurately collect the actual heating status of the end users.

[0063] Take Figure 3Taking four end-users 5-1, 5-2, 5-3, and 5-4 with the same apartment type (i.e., the same heating area) as an example. Among them, the wall 61 of user 5-1 remains unchanged, the window 62 is in a closed state, and a set of terminal heating devices 33 is installed indoors; the states of the wall 61 and the window 62 of user 5-2 are the same as those of user 5-1, but the number of terminal heating devices 33 is increased to two groups; the states of the window and the terminal heating devices 33 of user 5-3 are the same as those of user 5-1, but a heat-insulating layer 63 is added to the indoor wall 61 to improve the heat-insulating effect; the states of the wall 61 and the terminal heating devices 33 of user 5-4 are the same as those of user 5-1. However, the indoor window 62 is in an open state, resulting in a significant increase in the degree of heat exchange between indoors and outdoors.

[0064] It can be seen from Figure 3 that even for end-users with exactly the same apartment type, there are significant differences in their indoor heating conditions. The factors causing these differences in heating states include both static factors, such as the different numbers and positions of terminal heating devices 33, or different indoor decoration situations, and dynamic factors, such as the opening and closing states of doors and windows, etc. Since these influencing factors occur after the users' decoration and occupancy, this information cannot be fundamentally obtained by the heating provider and thus cannot be reflected in the heat load demand model.

[0065] For the above reasons, the existing heat load demand estimation models basically calculate the heat load demand of end-users by the method of "the heat required to raise the temperature of a unit area by one unit × heating area × (room temperature setting value - room temperature measured value)". Obviously, this estimation method will inevitably set the flow valves 34 of the user pipelines 3 of end-users with the same apartment type to the same opening degree. However, the opening degree of the valve that meets the heating demand of user 5-1 will inevitably cause overheating indoors for users 5-2 and 5-3.

[0066] In addition, the dynamic factors existing in the use process of user 5-4 will also cause the calculation of the existing heat load demand model to fail. Because in this case, it may occur that no matter how much the valve opening degree is increased, the indoor temperature does not rise, which will lead to an unreasonably over-amplified heat load demand of this heating household during the calculation of the heat load demand.

[0067] Thus, it can be seen that there are insurmountable problems in controlling the flow and temperature regulation of the heating system based on the estimation results of the heat load prediction model.

[0068] (2) Secondly, the existing various intelligent control methods focus on meeting the heating demands of each independent end-user and do not consider the influence of the distribution characteristics of the opening degrees of the flow valves of a large number of end-users on the overall energy consumption and safety of the system.

[0069] It can be seen from Figure 3It can be seen that for heating households with the same heating area, due to their different indoor heating conditions, when their corresponding terminal heating pipe network 3 meets their heating needs (that is, the difference between the temperature measurement value and the temperature setting is within an acceptable range), the valve opening may be in different states: when the valve opening is small, it means that when heating them with the water temperature at this time, only a small flow rate is needed to meet their heating needs. If a considerable number of users in the lower level of a secondary pipe network 2 meet their heating needs with a smaller valve opening, it must mean that the heat input into the secondary pipe network 2 exceeds the actual demand; conversely, when the valve opening is When it is relatively large, or even reaches 100%, it means that the user's heating demand may not be met at this time, or is in a state of being just met but extremely unstable, because the terminal pipe network corresponding to the user has reached its heating limit according to the current water temperature and can no longer cope with further increased heating demand (for example, the user further increases the temperature setting value, or the room temperature drops due to increased indoor and outdoor heat exchange). Obviously, if a considerable number of flow valves 34 of the users at the lower level of a secondary pipe network 2 are in this state of large opening, it means that the heat input by the secondary heat pipe network can no longer meet the heat demand of the users at the lower level.

[0070] It can be seen that if the overall distribution characteristics of valve opening of a large number of users are not counted and analyzed, it will be impossible to timely discover the heat waste or heating gap in the system, which will cause an increase in system energy consumption or adversely affect the safety of system operation.

[0071] (3) In addition, the top-down step-by-step adjustment method is likely to amplify the hysteresis of the flow and temperature changes of heating water, causing "oscillations" in the flow and temperature within the pipeline network.

[0072] When adopting a top-down step-by-step control method, the control center's regulation of flow and temperature needs to be transmitted step by step from the main pipe and branch pipe to the end user, and new regulation quantities need to be generated based on the feedback results after being transmitted to the end user. Due to the hysteresis of the flow and temperature changes of heating water, there is a constant misalignment between the regulation and the actual changes, which can easily cause fluctuations in the heat, flow and temperature of the entire network. Especially when the system is complex or external demand changes frequently, it is more likely to cause "oscillations" in the pipeline pressure, flow or temperature, which not only increases the energy consumption and operation risks of the system, but also affects the heating stability and comfort of the end users.

[0073] In order to solve the above problems existing in the existing multi-stage heating system control method, the embodiment of the present application provides a new intelligent control method for a multi-stage heating system, which uses a bottom-up approach to adaptively adjust the heating pipe network at each level, thereby achieving efficient, timely and safe distribution of heat within the system while ensuring heating for end users. Figure 4As shown, the intelligent control method includes the following operations:

[0074] For each user pipe network, adjust the opening degree of its flow valve based on the closed-loop feedback control strategy;

[0075] For each secondary pipe network, adjust the heating water flow of its main pipeline based on the pressure difference at its end and the statistical characteristics of the opening degrees of the flow valves of each user pipe network it includes;

[0076] For each primary pipe network, adjust the heating water flow of its main pipeline based on the heat profit and loss status of each secondary pipe network it includes and the statistical characteristics of the opening degrees of the flow valves of each user pipe network it includes;

[0077] For each heat source, adjust the heating degree of the heating water for this multi-level heating system based on the heat profit and loss status of each secondary pipe network heated by it.

[0078] The implementation process of this intelligent control method will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0079] <Regulation Process of the Flow Valve in the User Pipe Network>

[0080] Figure 5 Shows a flow chart for adjusting the opening degree of the flow valve of each user pipe network 3 in some specific embodiments. The above adjustment can be achieved through Figure 1B the terminal control unit 35 in. As Figure 5 shown, this adjustment process includes steps that are executed cyclically:

[0081] Step S31, obtain the user room temperature where the user pipe network is located;

[0082] Step S32, determine whether the user room temperature has achieved the preset room temperature adjustment target. If the determination result is no, execute step S33. If the determination result is yes, execute step S34;

[0083] Step S33, adjust the opening degree of the flow valve to move the user room temperature towards the room temperature adjustment target, and then return to step S31;

[0084] Step S34, determine whether the opening degree of the flow valve is within the optimal opening degree range. If the determination result is yes, execute step S35. If the determination result is no, execute step S36;

[0085] Step S35, maintain the opening degree of the flow valve, and then return to step S31;

[0086] Step S36: Adjust the opening degree of the flow valve to move the opening degree of the flow valve towards the optimal opening degree range, and then return to step S31.

[0087] Specifically, at any moment t, the real-time room temperature can be obtained through the temperature sensor installed in the user's room in step S31, and then in step S32, it is compared with the target room temperature preset by the user. If the deviation value between the two is outside the acceptable range, it indicates that the user's room temperature has not reached the room temperature adjustment target. At this time, in step S33, the opening degree of the flow valve is adjusted to make the real-time room temperature approach the target room temperature, and then after a time interval Δt, it returns to step S31 to make a new judgment. The above adjustment method of adjusting the room temperature to reach the room temperature setting value by adjusting the opening degree of the flow valve 34 can be implemented using various PID control algorithms known to those skilled in the art. Obviously, the above steps will be executed cyclically until the user's room temperature reaches the room temperature adjustment target, and then step S34 is entered.

[0088] Step S34 is used to judge whether the opening degree of the flow valve 34 is within the optimal opening degree range. Specifically, the terminal control unit 35 can obtain the opening degree information of the flow valve through the feedback device installed on the flow valve (generally, the valve opening degree is expressed as a percentage between 0 and 100%), and compare it with the preset optimal opening degree range. If the comparison result shows that the valve opening degree is within the optimal opening degree range, step S35 is executed, that is, the current valve opening degree remains unchanged, or only a fine adjustment is made to keep it stably within the optimal opening degree range. Then, the current moment t is updated at a certain time interval Δt and returns to step S31 to re-judge the heating state in the user's room; if the comparison result shows that the valve opening degree has not entered the optimal opening degree range at this time, step S36 is executed. According to the direction in which the current valve opening degree deviates from the optimal opening degree range, the valve opening degree is adjusted in the reverse direction to make the valve opening degree adjust towards the optimal opening degree range. Then, the current moment t is updated at a certain time step Δt and returns to step S31 to re-judge the heating state in the user's room.

[0089] It can be seen from the above steps that in the process of adjusting the flow valve 34 of the user's pipeline 3, the actual room temperature in the user's room reaches or approaches the user's set value as a priority adjustment target. After achieving the priority adjustment target by adjusting the valve opening, the flow valve 34 may still be in a state of low or high opening. It can be seen from the above analysis that the valve opening and its changing state can more directly and quickly reflect the degree of matching between the user-side input heat and actual demand: a small valve opening means that the heating water in the pipeline carries too much heat, resulting in waste, and vice versa, it means that there may be a hidden danger of insufficient heat carried by the heating water. Therefore, after the indoor temperature reaches the temperature set by the user, the heating water flow in the user's pipeline 3 is further adjusted with the valve opening in the optimal opening range as the secondary priority adjustment target. Through this adjustment method, at the terminal pipe network level, it is possible to effectively avoid the problem of inaccurate estimation results due to the inability to obtain the actual indoor heating status of the user when the heat load prediction model is used to adjust the valve opening; it is also ensured that the flow valve of the user pipe network 3 is in an energy-saving and safe operating range; at the same time, since this feedback adjustment is only carried out within the terminal pipe network, its control closed loop is short and the response speed is much higher than the long closed-loop feedback control method that is transmitted step by step from top to bottom.

[0090] In addition, the use of the above-mentioned control method in each user pipeline 3 in the same secondary pipeline network 2 can also effectively solve the problem that the existing heat load prediction model cannot accurately respond to the linkage effect between each user pipeline: when the heating water flows in multiple user pipelines 3 at the same level, adjusting the opening of the flow valve 34 of each user pipeline 3 will not only affect the flow of heating water in its own pipeline, but also have a linkage effect on the flow of heating water in the user pipelines 3 around it. For example, reducing the opening of a certain flow valve 34 will reduce the flow of the user pipeline 3 where it is located. At the same time, due to the increase in flow resistance here, the heating water will tend to flow to the surrounding pipelines, resulting in a corresponding increase in the flow of heating water in other user pipelines 3 with larger valve openings. This increase is bound to make users who have met their heating needs tend to reduce their valves, and in turn weaken the effect of the previous user reducing the valve.

[0091] It can be seen that the adjustment of each flow valve 34 will dynamically affect each other, and the input heat and actual heat demand of each user will change dynamically between matching and mismatching. Therefore, even if the existing heat load prediction model can accurately obtain the actual heating demand of the heating user and adjust each flow valve 34 in isolation based on the predicted value of the heat load prediction model, it will inevitably cause a linkage effect on other heating terminals, thereby resulting in the failure to achieve the expected effect.

[0092] Compared with this adjustment method, Figure 5The adopted adjustment method no longer guides the adjustment of the valve opening based on the estimated value of the prediction model, but adjusts the valve opening with a preset index (i.e., the valve opening is within the optimal opening range), so that the heating water can flow adaptively in each user pipe network, and finally achieve the balanced distribution of heat in the secondary pipe network 2 as a whole.

[0093] The selection of the optimal opening range should not only make the heating water entering the pipe network be fully utilized, but also avoid too large an opening and lose the ability to further adjust. Therefore, the ideal valve opening range should be in the direction closer to 100% in the range of 0-100%. That is, in a preferred embodiment, the median value of the optimal opening range is greater than 50%, such as 40%-80%.

[0094] Considering that in the heating pipe network, the farther the user pipe network 3 is from the heat inlet, the lower the pressure difference between the supply and return water in the pipeline will be caused by the hydraulic loss, and the higher the possibility of increasing the valve opening. Therefore, in some preferred embodiments, for each user pipe network 3 at the same level, the median value of the optimal opening range of its flow valve 34 is positively correlated with the distance from each user pipe network to the inlet of the secondary pipe network 2 at its upper level. For example: for the user pipe network 3 close to the inlet of the main supply pipeline 21, the median value of the optimal opening range of its flow valve 34 can be set to 55%, and correspondingly, the optimal opening range of its flow valve 34 is 35%-75%; for the user pipe network 3 far from the inlet of the main supply pipeline 21, the median value of the optimal opening range of its flow valve 34 can be set to 65%, and correspondingly, the optimal opening range of its flow valve 34 is 45%-85%. Setting different optimal opening ranges for the flow valve 34 according to the distance from the heat inlet can more accurately characterize the heating state of the user pipe network 3, which is beneficial to the accuracy of subsequent control of the secondary pipe network 2.

[0095] <Adjustment of the flow rate of heating water in the secondary pipe network>

[0096] As described above, the adjustment of the heating water in the secondary pipe network 2 can be achieved by controlling the frequency of the secondary circulation pump 23 by the secondary control unit 24. In some preferred embodiments, as Figure 6 shown, the flow rate of the heating water in the main pipeline of the secondary pipe network 2 can be adjusted by cyclically executing the following steps:

[0097] Step S21, obtaining the pressure difference at the end of the secondary pipe network and the statistical characteristics of the flow valve opening degrees of each user pipe network included in the secondary pipe network, where the statistical characteristics of the flow valve opening degrees include: the proportion of flow valves with valve openings less than, within, and greater than the optimal opening range;

[0098] Step S22: Determine whether the terminal pressure difference is lower than the safe pressure difference range. If the determination result is yes, increase the heating water flow rate of the main pipeline of the secondary pipe network, and then return to Step S21. If the determination result is no, execute Step S23;

[0099] Step S23: Determine whether the proportion of flow valves with valve openings in the optimal opening range exceeds the first proportion threshold. If the determination result is yes, maintain the heating water flow rate of the main pipeline of the secondary pipe network and return to Step S21. If the determination result is no, execute Step S24;

[0100] Step S24: Determine whether the proportion of flow valves with valve openings smaller than the optimal opening range exceeds the second proportion threshold. If the determination result is yes, reduce the heating water flow rate of the main pipeline of the secondary pipe network, and then return to Step S21. If the determination result is no, execute Step S25;

[0101] Step S25: Determine whether the proportion of flow valves with valve openings larger than the optimal opening range exceeds the third proportion threshold. If the determination result is yes, increase the heating water flow rate of the main pipeline of the secondary pipe network, and then return to Step S21. If the determination result is no, execute Step S26;

[0102] Step S26: Adjust the heating water flow rate of the main pipeline of the secondary pipe network to increase the proportion of flow valves with valve openings in the optimal opening range in the secondary pipe network, and then return to Step S21.

[0103] Specifically, in Step S21, first collect the terminal pressure difference in the secondary pipe network 2 and the valve opening information of each user pipe network 3 in the secondary pipe network 2.

[0104] The terminal pressure difference (or it can also be called the most unfavorable point pressure difference, etc.) generally refers to the supply-return water pressure difference at the farthest point (or the point with the greatest hydraulic resistance) from the heat source or heat inlet in a heating pipe network. When the terminal pressure difference is within the preset safe pressure difference range (for example, the terminal pressure difference is higher than a preset pressure difference lower limit value), it indicates that the heating pipe network is in a state where it can operate safely (but it does not mean that the system is in an energy-saving operation state). In some embodiments, various known pressure difference measuring instruments, such as digital pressure difference measuring instruments, etc., can be set at the farthest end of the secondary pipe network 2 from the heating water inlet to measure the supply-return water pressure difference, or, according to the evaluation of the heating water flow situation in the secondary pipe network 2, the pressure difference measuring instrument can be set at the position with the greatest hydraulic resistance to measure the supply-return water pressure difference. The above-mentioned measured terminal pressure difference can be transmitted to the secondary control unit 24 through wired or wireless communication.

[0105] As described above, the opening degree of the flow valve 34 of each user pipe network 3 can be obtained through the feedback device provided thereon and transmitted to the terminal control unit 35. After the terminal control unit 35 of each user pipe network 3 obtains the opening degree information of its corresponding flow valve 34, the information is further summarized to the secondary control unit 24 of the secondary pipe network 2 at its upper level. The secondary control unit 24 statistically obtains the opening degree statistical characteristics of each flow valve 34. In the embodiment of the present application, the opening degree statistical characteristics of each flow valve 34 included in a secondary pipe network 2 at least include the following characteristic values: the proportion of flow valves with valve opening less than, within, and greater than the optimal opening interval.

[0106] Figures 7A to 7D Respectively show different states that the flow valve opening characteristics may be in:

[0107] Figure 7A The state shown represents that in a secondary pipe network 2, the proportion of the number of flow valves 34 with openings within the optimal opening interval (i.e., the area between U min ~U max is relatively large in the total number of flow valves 34. According to the previous analysis, when the opening degree of a flow valve 34 is within the optimal opening interval, the user pipe network 3 where it is located can most efficiently and safely utilize the heating water in the secondary pipe network 2 where it is located. Correspondingly, when the proportion of flow valves 34 with openings within the optimal opening interval among the flow valves 34 at the lower level of a secondary pipe network 2 reaches a preset first proportional threshold, it can be considered that the heat carried by the heating water entering the secondary pipe network 2 is fully and safely utilized at this time, that is: the heat input by the secondary pipe network 2 at the current flow rate ("quantity") and water temperature ("quality") neither has a shortage of heat nor obvious heat waste.

[0108] Figure 7B The state shown represents that in a secondary pipe network 2, the proportion of the number of flow valves 34 with openings less than the optimal opening interval is relatively large in the total number of flow valves 34. When the valve opening distribution characteristic of the secondary pipe network 2 is in this state, it means that a considerable number of flow valves 34 are at a relatively small opening degree at this moment, and only a relatively small heating water flow rate is required to make the room temperature of the corresponding user meet the heating demand. Obviously, the total heat carried by the heating water entering the secondary pipe network 2 will be wasted at this time, resulting in insufficient heat exchange with the indoor air where each user pipe network 3 is located, and flowing back through the secondary return water pipeline.

[0109] Figure 7C The state shown represents that in a secondary pipe network 2, the proportion of the number of flow valves 34 with openings greater than the optimal opening interval is relatively large in the total number of flow valves 34. When a secondary pipe network 2 is in Figure 7CWhen in the state shown, it means that at this moment, a considerable number of flow valves 34 in the secondary pipe network 2 have been in or are close to the fully open state. As analyzed above, for the users corresponding to these fully open or nearly fully open flow valves 34, the room temperature indoors has either not reached the room temperature set value or barely reached the room temperature set value (because only when the measured room temperature continuously falls below the room temperature set value will the opening of the flow valve 34 continuously increase until it exceeds the optimal opening range), indicating that under the current heating water flow rate and water temperature conditions of the secondary pipe network 2, the total input heat may not be able to meet the sum of the actual heat requirements of its downstream individual user pipe networks 3.

[0110] Figure 7D The state shown indicates that in a secondary pipe network 2, the opening degrees of the respective flow valves 34 are relatively dispersed. When this situation occurs, there may not be a large gap between the total heat input to the secondary pipe network 2 and the sum of the actual heat requirements of the individual user pipe networks 3. Instead, due to the uneven flow of the heating water in the pipe network (i.e., the uneven distribution of heat), the room temperature of some users exceeds their set values, so they actively reduce the opening degree of the flow valve 34, while for other users whose room temperature has not reached the set value, they actively increase the opening degree of the flow valve 34.

[0111] It should be noted that in the embodiments of the present application, the statistical analysis of the opening degree distribution characteristics of the respective flow valves 34 is generally carried out within the range of the flow valves 34 in the active state or normal working state, that is, the user pipe network 3 where the flow valve 34 to be statistically analyzed is located is in the normal payment and heating state. For users who have not paid the fees or whose heating has been stopped for other reasons, the terminal control unit 35 of their user pipe network 3 has generally been remotely locked or actively closed. Correspondingly, the flow valve 34 is generally in the fully closed state, and its opening degree is generally recognized as a special state such as Null in the system. When statistically analyzing the opening degree distribution characteristics of the respective flow valves 34 at the downstream of a secondary heating pipe network 2, the flow valves 34 in the special states such as Null need to be excluded to avoid the statistical analysis of the pipelines that do not participate in the heating water circulation from affecting the analysis of the overall opening degree distribution state of the respective flow valves 34 in the heating pipe network.

[0112] After obtaining the end differential pressure of the secondary pipe network 2 and the statistical characteristics of the flow valve opening degrees through step S21, the heating water flow rate in its main pipeline can be adjusted respectively for different states of the secondary pipe network 2 through steps S22 to S26.

[0113] Among them, in step S22, first, it is judged whether the terminal pressure difference is lower than the safe pressure difference range (in some preferred embodiments, the lower limit of the safe pressure difference range is 0.015 MPa to 0.02 MPa). Since the terminal pressure difference dropping below the safe pressure difference range generally occurs during the adjustment process of reducing the heating water flow rate due to excessive heat input in the secondary pipe network 2, therefore, if the judgment result is yes, it indicates that continuously reducing the heating water flow rate will cause the flow condition of the heating water in the secondary pipe network 2 to deteriorate. At this time, the flow rate can be appropriately increased by slightly increasing the frequency of the secondary circulation pump, so that the terminal pressure difference returns to the safe pressure difference range again, and then after a time interval Δt, return to step S21 to obtain the updated terminal pressure difference and the valve opening distribution characteristics. In addition, it should be noted that in the embodiments of the present application, there is no limitation on whether to set an upper limit value for the safe pressure difference range, that is: only the lower limit value of the safe pressure difference range can be set, and as long as the terminal pressure difference is higher than the preset lower limit value, it is considered to be within the safe operating range.

[0114] If the judgment result of step S22 is no, it means that there is no safety problem caused by the deterioration of the heating water flow state in the secondary pipe network 2 currently, then it is possible to enter step S23 to further judge whether the proportion of the flow valves 34 with valve openings in the optimal opening range exceeds a preset first ratio threshold (for example, in the state shown in Figure 7A ). If the judgment result is yes, it means that the openings of most of the flow valves 34 are in the optimal opening range, and the heat input of the secondary pipe network 2 is relatively matched with the sum of the actual heat requirements of each user pipe network 3. The secondary pipe network 2 is in an energy-efficient and safe heating state. At this time, the flow rate of the main pipeline of the secondary pipe network 2 can be maintained, so that the secondary pipe network 2 continues to be in this heating state.

[0115] If the judgment result of step S23 is no, then enter step S24 to judge whether the proportion of the flow valves 34 with valve openings smaller than the optimal opening range exceeds a preset second ratio threshold (for example, in the state shown in Figure 7B ). If the judgment result is yes, it indicates that the openings of most of the flow valves 34 are smaller than the optimal opening range, that is, the heat input of the secondary pipe network 2 is greater than the sum of the actual heat requirements of each user pipe network 3. In order to avoid waste of heat, the flow rate of the main pipeline of the secondary pipe network 2 can be reduced, so that each of its lower-level users adjusts in the direction of increasing the opening of its flow valve.

[0116] It should be noted that if Figure 7BThe duration of the shown state is long enough. As the flow rate in the secondary pipe network 2 continuously decreases, the end differential pressure will drop below the safe differential pressure range. At this time, the end differential pressure in the secondary pipe network 2 is not within the safe differential pressure range, and the proportion of the flow valves 34 with valve openings less than the optimal opening range exceeds the preset second proportion threshold. In the embodiments of the present application, the above state is referred to as the heat surplus state. Obviously, when a secondary pipe network 2 is in the heat surplus state, the problem of mismatch between the input heat and the required heat cannot be solved by reducing the flow rate, and can only be solved by the temperature adjustment process described later.

[0117] If the judgment result of step S24 is negative, go to step S25 to judge whether the proportion of the flow valves 34 with valve openings greater than the optimal opening range exceeds the third proportion threshold (for example, in the Figure 7C shown state). If the judgment result is positive, it indicates that in the current heat supply water flow rate and water temperature state of the secondary pipe network 2, the total input heat may be less than the sum of the actual heat requirements of its subordinate user pipe networks 3. In the embodiments of the present application, this state is referred to as the heat deficit state. For a secondary pipe network 2 entering the heat deficit state, the main pipeline flow rate will be increased in step S25 to increase the heat input.

[0118] If the judgment result of step S25 is negative, it indicates that the opening degrees of the flow valves 34 in the secondary pipe network 2 are relatively dispersed (for example Figure 7D shown). As analyzed above, at this time, the opening degrees of the flow valves in the pipe network being too high or too low are not caused by a large difference between the total heat input and the total heat demand, but by uneven distribution of the heat supply water inside the pipe network. Therefore, in step S26, the main pipeline flow rate of the secondary pipe network 2 can be finely adjusted with a much smaller adjustment amplitude than in step S24 or step S25, so as to utilize the linkage effect when each flow valve 34 adjusts its opening degree, and make the distribution characteristics of the valve openings adaptively move in the direction of increasing the proportion of the flow valves 34 in the optimal opening range.

[0119] The first proportion threshold, the second proportion threshold, and the third proportion threshold are set to different values, which may have different effects on the state adjustment speed and stability of the secondary pipe network 2. For example, the lower the first proportion threshold, the easier it is for the secondary pipe network to enter the flow maintenance cycle. However, correspondingly, the proportion of the flow valves 34 with opening degrees not in the optimal opening range is also larger, that is, the secondary pipe network 2 is more likely to be determined to be in a state of mismatch between the total input heat and the total demand heat of each user pipe network; on the contrary, the higher the first proportion threshold, the longer the time required to adjust the heat supply water flow rate to make the secondary pipe network 2 enter the flow maintenance cycle. However, correspondingly, after entering this cycle, the matching state between the total input heat and the total demand heat of the secondary pipe network 2 is less likely to be broken.

[0120] Therefore, the reasonable ranges of the first ratio threshold, the second ratio threshold and the third ratio threshold can be determined by comprehensive evaluation based on the size of the secondary pipe network 2, the number of its lower user pipe networks 3, and the response speed of the room temperature change of each user to the opening adjustment of the flow valve 34. Preferably, the ratio threshold can be set in the following manner: the first ratio threshold is set to be greater than or equal to the second ratio threshold, and the second ratio threshold is set to be greater than or equal to the third ratio threshold. For example, in some specific embodiments, the preferred range of the first ratio threshold can be set to 60% to 80%, the preferred range of the second ratio threshold can be set to 55% to 60%, and the preferred range of the third ratio threshold can be set to 50% to 55%.

[0121] Through the description of the adjustment process of the secondary pipeline network 2, it can be seen that the method provided by the present application adopts the goals of balancing safety and energy saving at the secondary pipeline network level to achieve efficient distribution of heat in the pipeline network, and by monitoring the terminal pressure difference, it is ensured that in the process of reducing the heat flowing into the secondary pipeline network 2 so as to increase the opening of each flow valve 34, the flow rate is not too low, resulting in deterioration of the flow state; and then, under the premise of ensuring the minimum terminal supply and return water pressure difference, the opening of each flow valve 34 is moved as much as possible in the direction that can fully utilize the heat carried by the heating water.

[0122] In addition, the basis for flow regulation of the secondary pipe network 2 comes from the comparison result of the statistical characteristics of the opening of each valve and the corresponding proportional threshold value, rather than taking the sum of the heat load demands of each heating terminal as the basis for flow regulation as adopted in various heat load prediction models. The reason is that in addition to the existing heat load prediction model analyzed in the previous article being unable to accurately predict the heat load demand, it is also because for a secondary pipe network 2 containing multiple user pipe networks 3, there are often several user pipe networks 34 with too high valve openings and several heating terminals 34 with too low valve openings. This heat mismatch of individual heating terminals does not necessarily represent the heat mismatch of their superiors. The total heat input into the secondary pipe network 2 does not match the sum of the heat demands of all the heating terminals 34. Instead, it may be caused by the imbalance of the flow state of the heating water in various places. Since the flow state of the heating water often changes adaptively in a linked manner during the process of adjusting the opening of each flow valve 34, the above-mentioned imbalance may be adaptively balanced by adjusting the opening of each flow valve 34. Only when the opening distribution characteristics of all the flow valves 34 show a trend of overall movement in the direction of smaller opening or larger opening, can it be more accurately indicated that the secondary pipe network 2 has a heat mismatch problem.

[0123] On this basis, a closed-loop control based on the valve opening distribution characteristics is carried out inside the secondary pipe network 2, which can effectively shorten the feedback path length and adaptively form the "intake and output" of the input heat at the secondary pipe network 2 level: when there is a tendency of excessive heat input, the flow rate is quickly reduced to prevent excess heat from entering the secondary pipe network 2; when there is a heat deficit, more heat is quickly inhaled, so as to be able to respond more quickly to the changes in the total required heat of each user pipe network.

[0124] <Adjustment of the flow rate of the heating water in the primary pipe network>

[0125] The adjustment of the heating water in the primary pipe network 1 can be achieved by controlling the frequency of the primary circulation pump 13 by the primary control unit 14. In some preferred embodiments, as Figure 8 shown, the flow rate of the heating water in the main pipeline of the primary pipe network 1 can be adjusted by cyclically performing the following steps:

[0126] Step S11, obtain and count the heat profit and loss status of each secondary pipe network included in the primary pipe network, where the heat profit and loss status includes a heat surplus status and a heat deficit status;

[0127] Step S12, determine whether there is a secondary pipe network in the primary pipe network that is in a heat deficit state. If the determination result is yes, increase the flow rate of the heating water in the main pipeline of the primary pipe network, and then return to step S11. If the determination result is no, execute step S13;

[0128] Step S13, adjust the flow rate of the heating water in the main pipeline of the primary pipe network to increase the proportion of the flow valves in the optimal opening interval among the flow valves in its subordinate user pipe networks, and then return to step S11.

[0129] Specifically, the terminal pressure difference and the valve opening statistical characteristics of each secondary pipe network 2 can be further sent to the primary control unit, which counts the heat profit and loss status of each secondary pipe network 2 and executes the Figure 8 shown adjustment process according to the statistical results. Through Figure 8 it can be seen that as long as there is a secondary pipe network 2 in the primary pipe network 1 that is in a heat deficit state, the flow rate of the main pipeline of the primary pipe network 1 is immediately increased. Otherwise, by adjusting the flow rate of the main pipeline of the primary pipe network 1, each flow valve 34 in its subordinate is moved as close as possible to the optimal opening interval or maintained in the optimal opening interval.

[0130] The reason for adopting the above control logic is that in the embodiments of the present application, the determination basis of the heat deficit is that a considerable number of flow valves 34 in a secondary pipe network 2 are in a large opening interval. This situation generally occurs when the temperature drops in the whole region, and it is very likely that more secondary pipe networks 2 will have heat deficits in the near future. Therefore, the primary goal of the flow regulation of the primary pipe network 1 is to immediately increase the flow when a heat deficit occurs, so as to avoid the inability to timely compensate for more and more heat deficits due to the lag of the water temperature increase.

[0131] In addition, when the secondary pipe network 2 enters the heat surplus state, the flow rate of its main pipeline has basically decreased to a state where the end pressure difference reaches the lower limit of the safe pressure difference range. Therefore, the primary pipe network 1 no longer solves the heat surplus problem of its subordinate secondary pipe network 2 by reducing the flow rate of the main pipeline, but realizes reducing the heat entering the secondary pipe network 2 by reducing the heating degree of the heat supply source 4 for the heat supply water.

[0132] <Adjustment of the water temperature of the heat supply water>

[0133] The heat supply water flowing back from the main return pipeline 12 of the primary pipe network 1 is heated by the heat supply source 4 and then flows back into the system through the main supply pipeline 11. In the embodiments of the present application, the water temperature control unit 42 can adjust the heating degree of the heat supply source 4 for the heat supply water according to the heat profit and loss states of each subordinate secondary pipe network 2 it receives, so as to increase or decrease the water temperature of the heat supply water, thereby changing the total heat entering the system. As Figure 9 shown, in the embodiments of the present application, the heating degree of the heat supply source 4 for the heat supply water in the system can be adjusted by cyclically executing the following steps:

[0134] Step S41, obtain and count the heat profit and loss states of each secondary pipe network heated by the heat supply source, where the heat profit and loss states include the heat surplus state and the heat deficit state;

[0135] Step S42, judge whether there is a secondary pipe network in a heat deficit state among the secondary pipe networks heated by the heat supply source. If the judgment result is yes, increase the temperature of the heat supply water heated by the heat supply source, and then return to step S41. If the judgment result is no, execute step S43;

[0136] Step S43, judge whether there is a secondary pipe network in a heat surplus state among the secondary pipe networks heated by the heat supply source. If the judgment result is yes, execute step S44. If the judgment result is no, directly return to step S41;

[0137] Step S44: Determine whether the proportion of the secondary pipe network in a heat surplus state exceeds the fourth proportion threshold. If the determination result is yes, then reduce the temperature of the heating water heated by the heat source, and then return to step S41. If the determination result is no, directly return to step S41.

[0138] It can be seen that during the process of adjusting the water temperature in the entire heating system, as long as any secondary pipe network 2 has a heat deficit, it is necessary to increase the water temperature of the heating water in the system. The reason is that in the embodiments of the present application, the determination basis for the heat deficit is that a considerable number of flow valves 34 in a secondary pipe network 2 are in a large opening range. This situation generally occurs when the temperature drops in the entire region, and it is very likely that more secondary pipe networks 2 will have heat deficits in the near future. Therefore, the primary goal of temperature adjustment is to immediately increase the water temperature when the heat deficit appears, so as to avoid the inability to timely compensate the heat for more and more secondary pipe networks 2 with heat deficits due to the lag of water temperature increase.

[0139] The handling of the heat surplus phenomenon belongs to the secondary goal of water temperature adjustment, and the heating water is not cooled immediately when the first secondary pipe network 2 has a heat surplus. This is because the secondary pipe network 2 with a heat surplus must have met the heating requirements of the vast majority of its corresponding heating households. Due to the existence of the primary pipe network 1, the heat surplus in one or several secondary pipe networks 2 may still be absorbed by other secondary pipe networks 2 at the same level, that is, through the self-adaptive heat balance operation of the primary pipe network 1. Therefore, when the secondary pipe networks 2 as a whole show a trend of heat surplus, that is, when the proportion of the secondary pipe networks 2 in a heat surplus state exceeds the preset fourth proportion threshold (such as 30%), the cooling adjustment is started to avoid the additional energy consumption caused by frequent changes in water temperature.

[0140] <Optimization of System Operation Safety>

[0141] Figure 10 Shows a schematic flow chart for controlling the heating water flow of the primary pipe network 1 in some preferred embodiments. Compare Figure 10 With Figure 8 It can be found that during the process of controlling the flow of the primary pipe network 1, the following operations are added in step S12:

[0142] If there is a secondary pipe network 2 in a heat deficit state in the primary pipe network 1, while increasing the heating water flow of the main pipeline of the primary pipe network, lock the flow of the secondary pipe network whose actual heat consumption exceeds the preset heat proportion threshold.

[0143] Increasing the above operations during the process of controlling the flow rate of the primary pipe network 1 is because when there is a heat deficit in the secondary pipe network 2, while raising the water temperature, the secondary pipe network 2 in the heat deficit state will continuously increase the frequency of the secondary circulation pump to make more heating water flow into its pipe network. Since the rate of increase in water temperature is much lower than the rate of increase in the flow rate of heating water in the secondary pipe network 2, before the overall system water temperature rises significantly, the flow rate of some secondary pipe networks 2 may increase significantly, seizing the flow rate of other secondary pipe networks 2, resulting in more secondary pipe networks 2 entering the heat deficit state in a chain reaction. Although the increase in the number of secondary pipe networks 2 entering the heat deficit state is caused by the imbalance of heat distribution in the primary pipe network 1 in a short period of time, once the water temperature control unit 42 obtains the above statistical information, it will misjudge the total amount of heat deficit in the entire heating system, leading to excessive elevation of the water temperature and causing oscillation of the system water temperature.

[0144] Therefore, the historical data of the actual heat consumption of each secondary pipe network 2 can be statistically analyzed to obtain the fluctuation range of the proportion of the actual heat consumption of each secondary pipe network 2 in the entire primary pipe network 1 when it is in a normal heating state. Then, use ultrasonic heat meters and the like known to those skilled in the art to detect the actual heat consumption of each secondary heating pipe network 2 and compare it with the range of the proportion of the actual heat consumption in its normal heating state. Once the proportion of its actual heat consumption exceeds the preset heat proportion threshold, the flow rate of the heating water entering the secondary pipe network 2 is locked through a flow rate locking device (for example, a flow valve that can limit the flow rate) to ensure the safe operation of the entire system.

[0145] The specific implementation manners of the present application have been described in detail above. For those skilled in the art of this technology, without departing from the principle of the present application, several improvements and modifications can still be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. An intelligent control method for a multi-stage heating system, used to control a multi-stage heating system composed of a heat source, a primary pipe network, a secondary pipe network and a user pipe network cascaded, characterized in that: The following operations are included: For each user pipeline network, the opening of its flow valve is adjusted based on the closed-loop feedback control strategy; For each secondary pipe network, based on its terminal pressure difference and the statistical characteristics of the flow valve opening of each user pipe network included in it, adjust the heating water flow of its main pipeline; For each primary pipe network, based on the heat surplus and deficit status of each secondary pipe network included in it, and the statistical characteristics of the flow valve opening of each user pipe network included in it, adjust the heating water flow of its main pipeline; For each heat source, the degree of heating of the heating water of the multi-stage heating system is adjusted based on the heat surplus and deficit state of each secondary pipe network supplied by it.

2. The intelligent control method for a multi-stage heating system according to claim 1, characterized in that: The opening degree of the flow valve of the user pipe network is adjusted by cyclically executing the following steps: Step S31, obtaining the user room temperature where the user pipe network is located; Step S32, determining whether the user's room temperature has achieved the preset room temperature adjustment target, if the determination result is no, executing step S33, if the determination result is yes, executing step S34; Step S33, adjusting the opening of the flow valve so that the user room temperature moves toward the room temperature adjustment target, and then returning to step S31; Step S34, judging whether the opening of the flow valve is in the optimal opening range, if the judgment result is yes, executing step S35, if the judgment result is no, executing step S36; Step S35, maintaining the opening of the flow valve, and then returning to step S31; Step S36, adjusting the opening of the flow valve to move the opening of the flow valve to the optimal opening range, and then returning to step S31.

3. The intelligent control method for a multi-stage heating system according to claim 2, characterized in that: The middle value of the optimal opening range is greater than 50%.

4. The intelligent control method for a multi-stage heating system according to claim 3, characterized in that: The middle value of the optimal opening interval is positively correlated with the distance from the user pipe network to the entrance of the upper secondary pipe network.

5. The intelligent control method for a multi-stage heating system according to claim 1, characterized in that: The heating water flow rate of the main pipeline of the secondary pipeline network is adjusted by cyclically performing the following steps: Step S21, obtaining the terminal pressure difference of the secondary pipe network and the flow valve opening statistical characteristics of each user pipe network included in the secondary pipe network, wherein the flow valve opening statistical characteristics include: the proportion of flow valves with valve openings less than, within, and greater than the optimal opening range; Step S22, judging whether the terminal pressure difference is lower than the safety pressure difference interval, if the judgment result is yes, increasing the heating water flow of the main pipeline of the secondary pipe network, and then returning to step S21, if the judgment result is no, executing step S23; Step S23, determining whether the proportion of flow valves whose valve opening is in the optimal opening range exceeds a first proportion threshold; if the determination result is yes, maintaining the heating water flow of the main pipeline of the secondary pipe network, and returning to step S21; if the determination result is no, executing step S24; Step S24, determining whether the proportion of flow valves with valve openings less than the optimal opening interval exceeds a second ratio threshold; if the determination result is yes, reducing the heating water flow rate of the main pipeline of the secondary pipe network, and then returning to step S21; if the determination result is no, executing step S25; Step S25, determining whether the proportion of flow valves with valve openings greater than the optimal opening interval exceeds a third ratio threshold; if the determination result is yes, increasing the heating water flow rate of the main pipeline of the secondary pipe network, and then returning to step S21; if the determination result is no, executing step S26; Step S26, adjusting the heating water flow rate of the main pipeline of the secondary pipe network so that the proportion of flow valves whose valve openings in the secondary pipe network are in the optimal opening range is increased, and then returning to step S21.

6. The intelligent control method for a multi-stage heating system according to claim 5, characterized in that: The lower limit of the safety pressure difference range is 0.015MPa to 0.02MPa.

7. The intelligent control method for a multi-stage heating system according to claim 5, characterized in that: The first ratio threshold is greater than or equal to the second ratio threshold; The second ratio threshold is greater than or equal to the third ratio threshold.

8. The intelligent control method for a multi-stage heating system according to claim 1, characterized in that: The heating water flow rate of the main pipeline of the primary pipeline network is adjusted by cyclically performing the following steps: Step S11, obtaining and counting the heat surplus and deficit status of each secondary pipe network included in the primary pipe network, wherein the heat surplus and deficit status includes a heat surplus state and a heat deficit state; Step S12, determining whether there is a secondary pipe network in a heat loss state in the primary pipe network, if the determination result is yes, increasing the heating water flow rate of the main pipe of the primary pipe network, and then returning to step S11, if the determination result is no, executing step S13; Step S13, adjusting the heating water flow of the main pipeline of the primary pipe network so that the proportion of flow valves whose valve openings are in the optimal opening range in the downstream user pipe network is increased, and then returning to step S11.

9. The intelligent control method for a multi-stage heating system according to claim 1, characterized in that: The degree of heating of the heating water in the system by the heat source is adjusted by cyclically performing the following steps: Step S41, obtaining and counting the heat surplus and deficit state of each secondary pipe network supplied by the heat source, wherein the heat surplus and deficit state includes a heat surplus state and a heat deficit state; Step S42, determining whether there is a secondary pipe network in a heat loss state among the secondary pipe networks heated by the heat source, if the determination result is yes, increasing the temperature of the heating water heated by the heat source, and then returning to step S41, if the determination result is no, executing step S43; Step S43, determining whether there is a secondary pipe network in a heat surplus state among the secondary pipe networks supplied by the heat source, if the determination result is yes, executing step S44, if the determination result is no, directly returning to step S41; Step S44, determine whether the proportion of the secondary pipeline network in a heat surplus state exceeds the fourth ratio threshold. If the judgment result is yes, reduce the temperature of the heating water heated by the heat source, and then return to step S41. If the judgment result is no, directly return to step S41.

10. The intelligent control method for a multi-stage heating system according to claim 8 or claim 9, characterized in that: When the terminal pressure difference of the secondary pipe network is not in the safe pressure difference interval, and the proportion of flow valves in the secondary pipe network whose valve opening is less than the optimal opening interval exceeds a second ratio threshold, the secondary pipe network is in a heat surplus state; When the proportion of flow valves whose valve openings in the secondary pipe network are greater than the optimal opening range exceeds a third ratio threshold, the secondary pipe network is in a heat loss state.

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