A method for initial hydraulic regulation of heating metering system based on resistance identification

Abstract

The present invention discloses a method for initial hydraulic regulation of a heating metering system based on resistance identification, comprising the following steps: S1, obtaining a "resistance coefficient-valve opening" characteristic curve of each balancing valve; S2, forming a search range S of the resistance coefficient of each pipe section at the thermal inlet; n ; S3, adjust the balance valve of each thermal inlet pipe section to the fully open state, adjust the water pump to the design head and operate it in a constant pressure difference mode, and obtain the flow data of each thermal inlet pipe section as the measured flow; S4, use the particle swarm resistance optimization identification algorithm to search for the resistance coefficient in the range S n The thermal inlet resistance coefficient is generated and brought into the hydraulic calculation model to obtain the calculated flow rate of each thermal inlet pipe section; S5 substitutes the measured flow rate and the calculated flow rate into the objective function of the particle swarm resistance optimization identification algorithm to obtain the actual resistance coefficient S t ; S6. Substitute the calculated flow rate and the design flow rate into the objective function of the particle swarm resistance optimization identification algorithm to obtain the resistance coefficient S of the thermal inlet pipe section under the design flow rate c ; S7, S t and S c The difference is the change in the resistance of the balancing valve. The characteristic curve of the "resistance coefficient-valve opening" of the balancing valve is referred to to adjust each balancing valve to complete the initial hydraulic adjustment. Compared with the prior art, the beneficial effect of the present invention is that the flow is distributed completely according to the resistance coefficient, which is more accurate, fast and convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of heating, and in particular relates to a hydraulic initial regulation method of a heating metering system based on resistance identification. Background Art

[0002] Hydraulic imbalance in the heating network is one of the important reasons for the high energy consumption of heating. Hydraulic imbalance will directly lead to thermal imbalance in the heating system, resulting in energy waste and reduced efficiency of the heating system. According to the cause of hydraulic imbalance, hydraulic imbalance can be divided into static hydraulic imbalance and dynamic hydraulic imbalance. Static hydraulic imbalance is inherent in the heating system itself, and is caused by the deviation of the actual resistance coefficient of the pipeline system from the design value. With the continuous expansion of the scale of the heating network and the increasing complexity of its structure, static hydraulic imbalance is becoming more and more serious.

[0003] In order to solve the static hydraulic imbalance, the heating network will be initially adjusted at the beginning of the heating season. The commonly used initial adjustment methods are proportional adjustment method, compensation adjustment method, return water temperature adjustment method, simulation analysis method, etc. No matter which initial adjustment method is used, it faces a biggest problem: the resistance coefficient of the heat user is difficult to measure directly. The existing hydraulic initial adjustment method requires staff to carry professional equipment for repeated debugging, especially for the hydraulic initial adjustment of the large-scale and complex structure of the heating metering secondary network, which requires a lot of manpower and material resources, and the accuracy of the initial adjustment cannot be guaranteed. Summary of the invention

[0004] The details of one or more embodiments of the present invention are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent.

[0005] The present invention provides a method for hydraulic initial regulation of a heating metering system based on resistance identification. The method utilizes flow information and a particle swarm resistance optimization identification algorithm to optimize and identify the resistance coefficient, and calculates the actual resistance coefficient of the heat user and the resistance coefficient at the design flow rate. Combined with the "resistance coefficient-valve opening" characteristic curve of the balancing valve, the balancing valve opening is quickly determined to achieve accurate and rapid hydraulic initial regulation.

[0006] The present invention discloses a method for initial hydraulic regulation of a heating metering system based on resistance identification, comprising the following steps:

[0007] S1. Count the balancing valve information of each heat inlet pipe section to obtain the "resistance coefficient-valve opening" characteristic curve of each balancing valve;

[0008] S2, according to the resistance coefficient S of the pipe section design at each thermal inlet x And by setting the upper and lower fluctuation ranges, the fluctuation range S of the resistance coefficient can be determined. dAccording to the "resistance coefficient-valve opening" characteristic curve of the balancing valve on each thermal inlet pipe section, the corresponding balancing valve resistance coefficient fluctuation range S is determined. a , S d and S a The search range S of the resistance coefficient of each pipe section at the thermal inlet is formed by superimposing the upper and lower limits. n ;

[0009] S3, adjust the balance valve of each thermal inlet pipe section to the fully open state, adjust the water pump to the design head and operate in a constant pressure difference mode, and obtain the flow data of each thermal inlet pipe section as the measured flow; use the particle swarm resistance optimization identification algorithm to search for the resistance coefficient in the range S n The resistance coefficient of each thermal inlet pipe section is generated internally, and the generated resistance coefficient of each thermal inlet pipe section is substituted into the basic loop method hydraulic calculation model to obtain the calculated flow rate of each thermal inlet pipe section;

[0010] S4. Substitute the measured flow rate and calculated flow rate into the objective function of the particle swarm resistance optimization identification algorithm. The objective function is:

[0011]

[0012] Where: minf(S) is the objective function of the particle swarm resistance optimization identification algorithm; G n To calculate the flow rate; GC n is the measured flow rate; n is the number of thermal inlets;

[0013] When the calculated flow rate of the pipe section at the thermal inlet and the measured flow rate of the pipe section at the thermal inlet meet the error requirements, the corresponding resistance coefficient is the actual resistance coefficient S of the pipe section at the thermal inlet. t ;

[0014] S5. Substitute the calculated flow rate and the designed flow rate into the objective function of the particle swarm resistance optimization identification algorithm. The objective function is:

[0015]

[0016] Where: minf(S) is the objective function of the particle swarm resistance optimization identification algorithm; G n To calculate the flow rate; GD n is the design flow rate of each thermal inlet; n is the number of thermal inlets;

[0017] When the calculated flow rate of the pipe section at the thermal inlet meets the error requirement with the design flow rate of the pipe section at the thermal inlet, the corresponding resistance coefficient is the resistance coefficient S under the design flow rate of the pipe section at the thermal inlet. c ;

[0018] S6, ΔSp =S c -S t ; Difference ΔS p is the change in the resistance of the balancing valve. When the change in the resistance coefficient of the balancing valve is known, ΔS p In the case of the balance valve, the balance valve opening range ΔK is determined according to the characteristic curve of the balance valve's "resistance coefficient-valve opening" v And adjust the balancing valves of the pipe sections at each thermal inlet. When all the balancing valves are adjusted, the initial hydraulic adjustment is completed.

[0019] In some embodiments, in step S2:

[0020]

[0021] Where: S c is the resistance coefficient for pure pipe section and fixed resistance accessories, (Pa / (m 3 / h) 2 );λ is the friction coefficient of the pipeline; d n is the diameter of the pipe section, m; l n is the length of the pipe section, m; ξ n is the local resistance coefficient of the pipeline; ρ n is the fluid density in the pipe section, kg / m 3 ;

[0022] The S d and the S x The relationship between them is:

[0023] 0.8S x ≤S d ≤1.2S x .

[0024] In some implementations, the measured flow in step S3 is obtained through a remote heat meter.

[0025] In some embodiments, the objective function minf(S) has a value ranging from 0.01 to 0.0001.

[0026] In some implementations, step S1 also includes:

[0027] According to the setting drawings and on-site surveys, the distribution map of the heating network is obtained; according to the principles of graph theory, the line segments with constant flow and no branch points are regarded as pipe segments, and the branch points are regarded as nodes. The directed topological graph of the heating network is established according to the flow direction of water in the network, and the pipe segments and nodes are numbered.

[0028] In some embodiments, the particle swarm resistance optimization identification algorithm comprises the following steps:

[0029] 1) Particle initialization: Set the maximum number of iterations K to 200-500, the objective function accuracy to 0.01-0.0001, and the population size to 1-2 times the number of independent variables; the number of independent variables is equal to the number of thermal inlets, and the drag coefficient search range S n Generate the initial population using uniform random distribution;

[0030] 2) Update speed and position: In each iteration, the position and speed of the particle swarm need to be updated to gradually search for the optimal solution; the nonlinear decreasing inertia weight is used in updating the position and speed of the particle swarm:

[0031]

[0032] Where: w c is the inertia weight at the cth iteration; w start is the initial weight, take 0.9; w end is the final weight, which is 0.1; c is the current number of iterations; d is the decrease rate, which is 5; K is the maximum number of iterations;

[0033] 3) Termination criterion: The termination criterion indicates the conditions under which the improved particle swarm evolution algorithm can output the optimal solution, which includes the maximum number of iterations K and the accuracy of the objective function. When the maximum number of iterations is reached or the calculation accuracy is reached, the program terminates and outputs the identified optimal resistance coefficient.

[0034] In some embodiments, the "resistance coefficient-valve opening" characteristic curve is obtained by using a balancing valve of the same model as the thermal inlet to perform a pressure difference experiment at both ends of the valve at different openings.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The hydraulic initial regulation method proposed in the present invention distributes the flow completely according to the resistance coefficient, which is more accurate, fast and convenient. Most of the work is completed by the computer and the calculation time is very short.

[0037] 2. The hydraulic initial regulation method proposed in the present invention can identify the actual resistance coefficient of the pipe section in real time, which is not only suitable for the initial hydraulic regulation of hot water supply, but also can be applied to the dynamic hydraulic regulation of the heating system.

[0038] 3. It is particularly suitable for heating systems equipped with remote heat meters. It does not require additional communication tools and auxiliary equipment. It can quickly determine the balance valve opening by simply obtaining relevant flow information and combining the "resistance coefficient-valve opening" characteristic curve to achieve accurate and rapid hydraulic initial adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0040] Figure 1 It is a schematic diagram of the process structure of the present invention.

[0041] Figure 2 This is a schematic diagram of the pipe network topology model of the present invention.

[0042] Figure 3 It is a schematic diagram of the "resistance coefficient-valve opening" curve of the balancing valve of the present invention.

[0043] Figure 4 It is a schematic diagram of the optimization identification process of the actual resistance coefficient of the thermal inlet of the present invention.

[0044] Figure 5 It is a schematic diagram of the resistance coefficient optimization identification process when the thermal inlet is at the design flow rate of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0046] Obviously, the drawings described below are only some examples or embodiments of the present invention. For ordinary technicians in this field, the present invention can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed by the present invention, some changes in design, manufacturing or production based on the technical content disclosed by the present invention are just conventional technical means, and should not be understood as insufficient content disclosed by the present invention.

[0047] Reference to "embodiments" in the present invention means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in the present invention may be combined with other embodiments without conflict.

[0048] The present invention discloses a method for initial hydraulic regulation of a heating metering system based on resistance identification, comprising the following steps:

[0049] Step 1: Obtain the distribution of the heating network based on the setting drawings and field surveys. According to the principles of graph theory, the line segments with constant flow and no branch points are regarded as pipe segments, and the branch points are regarded as nodes; among them, the thermal inlet is regarded as the pipe segment with great resistance, and the directed topology of the heating network is established in combination with the flow direction of the water in the pipe network, and the nodes and pipe segments are numbered.

[0050] Specifically, assuming that a heating secondary network has four heat inlets and one circulating water pump, the network topology model and numbering format are as follows: Figure 2 Among them, the solid line section is the water supply section, and the dotted line section is the return section.

[0051] Step 2: Collect the brand, model, and caliber information of the balancing valves on the pipe sections at each thermal inlet. The "resistance coefficient-valve opening" characteristic curve of the corresponding balancing valve can be obtained from the valve manufacturer. You can also use the same model of balancing valve as the thermal inlet to conduct experiments on the pressure difference between the two ends of the valve at different openings, and then find the "resistance coefficient-valve opening" characteristic curve of the balancing valve.

[0052] Step 3: According to the resistance coefficient S of the pipe section design at each thermal inlet x And by setting the upper and lower fluctuation ranges, the fluctuation range S of the resistance coefficient can be determined. d According to the "resistance coefficient-valve opening" characteristic curve of the balancing valve on each thermal inlet pipe section, the corresponding balancing valve resistance coefficient fluctuation range S is determined. a , S d and S a The search range S of the resistance coefficient of each pipe section at the thermal inlet is formed by superimposing the upper and lower limits. n During hydraulic regulation, only the balancing valve at the thermal inlet is often adjusted, and the supply and return water main pipe sections are often not much different from the design conditions. It is believed that the resistance coefficient of the supply and return water main pipe sections is the same as the resistance coefficient in the design conditions. Therefore, it is only necessary to determine the resistance coefficient search range of the pipe sections at each thermal inlet.

[0053] The thermal inlet includes pure pipe sections, fixed resistance accessories and balancing valves, so the thermal inlet resistance search range is the sum of the pure pipe section resistance coefficient, the fixed resistance accessory resistance coefficient and the balancing valve resistance fluctuation range. For pure pipe sections and fixed resistance accessories, such as heat meters, filters and other accessories, first calculate according to the design situation, and the calculation method is as follows:

[0054]

[0055] Where: S xis the resistance coefficient for pure pipe section and fixed resistance accessories, (Pa / (m 3 / h) 2 );λ is the friction coefficient of the pipeline; d n is the diameter of the pipe section, m; l n is the length of the pipe section, m; ξ n is the local resistance coefficient of the pipeline; ρ n is the fluid density in the pipe section, kg / m 3 ;

[0056] Find S x Then the fluctuation range is limited based on industrial design experience. Usually, the fluctuation range meets the following relationship:

[0057] 0.8S x ≤S d ≤1.2S x .

[0058] For the balancing valve, the fluctuation range S of the balancing valve resistance coefficient is determined according to the "resistance coefficient-valve opening" characteristic curve. a .

[0059] Then through S d and S a The upper and lower limits between them are superimposed to obtain the final search range S of the resistance coefficient of each pipe section at the thermal inlet. n ;

[0060] That is, S n =S d +S a ;

[0061] Step 4: Adjust the balancing valve of each thermal inlet pipe section to the fully open state, adjust the water pump to the design head and operate in a constant pressure difference mode, obtain the flow data of each thermal inlet pipe section from the remote heat meter as the measured flow; use the particle swarm resistance optimization identification algorithm to search for the resistance coefficient in the range S n The resistance coefficient of each thermal inlet pipe section is generated internally, and the generated resistance coefficient of each thermal inlet pipe section is substituted into the basic loop method hydraulic calculation model to obtain the calculated flow rate of each thermal inlet pipe section;

[0062] Step 5: Based on the calculated flow rate and measured flow rate in step 4, substitute them into the objective function of the particle swarm resistance optimization identification algorithm. The objective function is:

[0063]

[0064] Where: minf(S) is the objective function of the particle swarm resistance optimization identification algorithm; G n To calculate the flow rate; GC nis the measured flow rate; n is the number of thermal inlets;

[0065] When the calculated flow rate of the pipe section at the thermal inlet and the measured flow rate of the pipe section at the thermal inlet meet the error requirements, the corresponding resistance coefficient is the actual resistance coefficient S of the pipe section at the thermal inlet. t ;

[0066] Step 6: Based on the calculated flow rate and design flow rate in step 4, substitute them into the objective function of the particle swarm resistance optimization identification algorithm. The objective function is:

[0067] Where: minf(S) is the objective function of the particle swarm resistance optimization identification algorithm; G n To calculate the flow rate; GD n is the design flow rate of each thermal inlet; n is the number of thermal inlets;

[0068] When the calculated flow rate of the pipe section at the thermal inlet meets the error requirement with the design flow rate of the pipe section at the thermal inlet, the corresponding resistance coefficient is the resistance coefficient S under the design flow rate of the pipe section at the thermal inlet. c ;

[0069] Step 7: ΔS p =S c -S t ; Difference ΔS p is the change in the resistance of the balancing valve. When the change in the resistance coefficient of the balancing valve is known, ΔS p In the case of the balance valve, the balance valve opening range ΔK is determined according to the characteristic curve of the balance valve's "resistance coefficient-valve opening" v And adjust the balancing valves of the pipe sections at each thermal inlet. When all the balancing valves are adjusted, the initial hydraulic adjustment is completed.

[0070] Among them, in step 5 and step 6, the numerical range of minf(S) is 0.01-0.0001, and its precision is changed by changing its numerical range.

[0071] In some embodiments, the particle swarm resistance optimization identification algorithm includes the following steps:

[0072] 1) Particle initialization: Set the maximum number of iterations K to 200-500, the objective function accuracy to 0.01-0.0001, and the population size to 1-2 times the number of independent variables; the number of independent variables is equal to the number of thermal inlets, and the drag coefficient search range S n Generate the initial population using uniform random distribution;

[0073] 2) Update speed and position: In each iteration, the position and speed of the particle swarm need to be updated to gradually search for the optimal solution; the nonlinear decreasing inertia weight is used in updating the position and speed of the particle swarm:

[0074]

[0075] Where: w c is the inertia weight at the cth iteration; w start is the initial weight, take 0.9; w end is the final weight, which is 0.1; c is the current number of iterations; d is the decrease rate, which is 5; K is the maximum number of iterations;

[0076] Compared with the use of fixed inertia weights, the use of nonlinear decreasing inertia weights has stronger global search capabilities at the initial stage and stronger local search capabilities when approaching the optimal solution. The use of nonlinear decreasing weights can improve the accuracy of the particle swarm resistance optimization identification algorithm.

[0077] 3) Termination criterion: The termination criterion indicates the condition under which the particle swarm evolution algorithm can output the optimal solution. Generally, when the maximum number of iterations K is reached or the calculation accuracy is reached, the program terminates and outputs the identified optimal resistance coefficient.

[0078] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for initial hydraulic regulation of a heating metering system based on resistance identification, characterized in that: The following steps are involved: S1. Count the balancing valve information of each heat inlet pipe section to obtain the "resistance coefficient-valve opening" characteristic curve of each balancing valve; S2, resistance coefficient S according to the design of pure pipe section and fixed resistance accessories on each thermal inlet x , and determine S by setting the upper and lower fluctuation ranges x The fluctuation range of the drag coefficient S s According to the "resistance coefficient-valve opening" characteristic curve of the balancing valve on each thermal inlet pipe section, the fluctuation range S of the resistance coefficient of the balancing valve on each thermal inlet pipe section is determined. a , S d and S a The search range S of the resistance coefficient of each pipe section at the thermal inlet is formed by superimposing the upper and lower limits. n ; S3, adjust the balance valve of each thermal inlet pipe section to the fully open state, adjust the water pump to the design head and operate in a constant pressure difference mode, and obtain the flow data of each thermal inlet pipe section as the measured flow; use the particle swarm resistance optimization identification algorithm to search for the resistance coefficient in the range S n The resistance coefficient of each thermal inlet pipe section is generated internally and substituted into the basic loop method hydraulic calculation model to obtain the calculated flow rate of each thermal inlet pipe section; S4. Substitute the measured flow rate and calculated flow rate into the objective function of the particle swarm resistance optimization identification algorithm. The objective function is: Where: minf(S) is the objective function of the particle swarm resistance optimization identification algorithm; G n To calculate the flow rate; GC n is the measured flow rate; n is the number of thermal inlets; When the calculated flow rate of the pipe section at the thermal inlet and the measured flow rate of the pipe section at the thermal inlet meet the error requirements, the corresponding resistance coefficient is the actual resistance coefficient S of the pipe section at the thermal inlet. t ; S5. Substitute the calculated flow rate and the designed flow rate into the objective function of the particle swarm resistance optimization identification algorithm. The objective function is: Where: minf(S) is the objective function of the particle swarm resistance optimization identification algorithm; G n To calculate the flow rate; GD n is the design flow rate of each thermal inlet; n is the number of thermal inlets; When the calculated flow rate of the pipe section at the thermal inlet meets the error requirement with the design flow rate of the pipe section at the thermal inlet, the corresponding resistance coefficient is the resistance coefficient S under the design flow rate of the pipe section at the thermal inlet. c ; S6, ΔS p =S c -S t ; Difference ΔS p is the change in the resistance of the balancing valve. When the change in the resistance coefficient of the balancing valve is known, ΔS p In the case of a balance valve, the balance valve opening range ΔK is determined according to the characteristic curve of the balance valve's "resistance coefficient-valve opening" v And adjust the balancing valves of the pipe sections at each thermal inlet. When all the balancing valves are adjusted, the initial hydraulic adjustment is completed.

2. The method for initial hydraulic regulation of a heating metering system based on resistance identification according to claim 1 is characterized in that: In step S2: Where: S x is the resistance coefficient for the design of pure pipe sections and fixed resistance accessories, (Pa / (m 3 / h) 2 );λ is the friction coefficient of the pipeline; d n is the diameter of the pipe section, m; l n is the length of the pipe section, m; ξ n is the local resistance coefficient of the pipeline; ρ n is the fluid density in the pipe section, kg / m 3 ; The S d and the S x The relationship between them is: 0.8S x ≤S d ≤1.2S x 。 3. The method for initial hydraulic regulation of a heating metering system based on resistance identification according to claim 1 is characterized in that: The measured flow rate in step S3 is obtained through a remote heat meter.

4. The method for initial hydraulic regulation of a heat supply metering system based on resistance identification according to claim 1 is characterized in that: The numerical range of the objective function minf(S) is 0.01-0.0001.

5. The method for initial hydraulic regulation of a heat supply metering system based on resistance identification according to claim 1 is characterized in that: Step S1 also includes: According to the setting drawings and on-site surveys, the distribution map of the heating network is obtained; according to the principles of graph theory, the line segments with constant flow and no branch points are regarded as pipe segments, and the branch points are regarded as nodes. The directed topological graph of the heating network is established according to the flow direction of water in the network, and the pipe segments and nodes are numbered.

6. The method for initial hydraulic regulation of a heat supply metering system based on resistance identification according to claim 1 is characterized in that: The particle swarm resistance optimization identification algorithm comprises the following steps: 1) Particle initialization: Set the maximum number of iterations K to 200-500, the objective function accuracy to 0.01-0.0001, and the population size to 1-2 times the number of independent variables; the number of independent variables is equal to the number of thermal inlets, and the drag coefficient search range S n Generate the initial population using uniform random distribution; 2) Update speed and position: In each iteration, the position and speed of the particle swarm need to be updated to gradually search for the optimal solution; the nonlinear decreasing inertia weight is used in updating the position and speed of the particle swarm: Where: w c is the inertia weight at the cth iteration; w start is the initial weight, take 0.9; w end is the final weight, which is 0.1; c is the current number of iterations; d is the decrease rate, which is 5; K is the maximum number of iterations; e is a natural constant; 3) Termination criterion: The termination criterion indicates the conditions under which the improved particle swarm evolution algorithm can output the optimal solution, which includes the maximum number of iterations K and the accuracy of the objective function. When the maximum number of iterations is reached or the calculation accuracy is reached, the program terminates and outputs the identified optimal resistance coefficient.

7. The method for initial hydraulic regulation of a heat supply metering system based on resistance identification according to claim 1 is characterized in that: The "resistance coefficient-valve opening" characteristic curve is obtained by using a balancing valve of the same model as the thermal inlet to conduct a pressure difference experiment at both ends of the valve at different openings.

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