System for judging whether water loss state of heat exchange station belongs to large-scale water loss or not, application of system and judgment method

Abstract

The invention relates to a system for judging whether the water loss state of a heat exchange station belongs to large-scale water loss or not, which comprises a first temperature sensor and a second temperature sensor, the first ultrasonic heat meter is used for measuring water supply pressure Psup; the first pressure sensor is used for measuring water supply pressure Psup; the evaluation system is used for evaluating whether the water loss state belongs to large-scale water loss or not; the condition of large-scale water loss is that the accumulated water supplementing amount of the water supplementing pipeline is greater than the allowable leakage amount of the total water amount of the pipe network in unit time t. When the system and the method are used for judging large-scale water loss, automatic monitoring and judgment can be stably carried out for a long time, a reliable basis is provided for water loss diagnosis, and the labor cost is reduced; and the mass flow error is controlled within an extremely small range, so that more reliable data support is provided for the overall operation of the heat exchange station.

Description

Technical Field

[0001] The present invention relates to the technical field of heating management, and particularly to a system for judging whether the water loss state of a heat exchange station belongs to large-scale water loss, its use and judgment method. Background Art

[0002] A heat exchange station usually includes parts such as heat exchangers, water pumps, pipelines, valves, and control systems. Water loss may occur in any of these parts. Common reasons for water loss may include leakage, equipment failure, operation errors, and users privately drawing water from the pipeline.

[0003] Generally speaking, there is indeed a reference range for the water loss rate of a heating system. According to some materials, the water loss rate under normal circumstances may be between 0.5% and 2% of the system circulating water volume. However, this range may vary due to factors such as system scale, design, and operating conditions.

[0004] If the water loss of a heat exchange station is abnormal, the manager needs to conduct on-site inspections to determine the cause of water loss. However, for a heating company, when it needs to manage dozens or hundreds of heat exchange stations at the same time, it is very difficult to monitor water loss abnormalities by relying solely on manual methods.

[0005] To solve this technical problem, the present invention needs to provide an evaluation system and evaluation method for the water loss state of a heat exchange station to quickly determine the station where water loss abnormalities occur. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the present invention provides a system for judging whether the water loss state of a heat exchange station belongs to large-scale water loss,

[0007] including a first temperature sensor respectively arranged on the water supply pipeline for measuring the water supply temperature T sup and a first ultrasonic heat meter for measuring the water supply volume flow Q v,sup in the water supply pipeline and a first pressure sensor for measuring the water supply pressure P sup ;

[0008] including a second temperature sensor arranged on the return water pipeline for measuring the return water temperature T ret and a second ultrasonic heat meter for measuring the return water flow Q v,ret in the return water pipeline and a second pressure sensor for measuring the return water pressure P ret ;

[0009] further including a third temperature sensor arranged on the make-up water pipeline for measuring the make-up water temperature T makeup and an ultrasonic water meter for measuring the make-up water volume flow Q v,makeup and a pressure sensor for measuring the pressure P makeupThe third pressure sensor;

[0010] It further includes an evaluation system for evaluating whether the water loss state belongs to large-scale water loss; the condition for large-scale water loss is that within a unit time t, the cumulative water replenishment volume of the water replenishment pipeline is greater than the allowable leakage volume of the total water volume of the pipe network.

[0011] Based on the above solution, the specific condition for evaluating the water loss state is:

[0012]

[0013] Among them,

[0014] is: the cumulative mass of system water replenishment within a certain time range;

[0015] Q v,makeup is the cumulative volume flow rate of water flowing through the meter measured within time t;

[0016] ρ makeup is the density of water in the water replenishment pipeline (3) within time t;

[0017] ρ total is the average density of water in the water inlet pipeline 1 and the water return pipeline 2 within time t;

[0018] V total : the total water capacity of the pipe network (m 3 );

[0019] k: leakage rate coefficient.

[0020] Based on the above solution, when in this case, it is necessary to further determine according to the pressure drop rate of the water return pipeline (2).

[0021] Based on the above solution, the condition for further determination is: the pressure drop rate ΔP of the water return pipeline (2) ret / Δt < -3 kPa / min, and it continues to decrease, and finally it is determined that there is a large-scale water loss phenomenon.

[0022] The present invention also provides a method for judging whether the water loss state of a heat exchange station belongs to large-scale water loss, using the above system.

[0023] The specific method includes the following steps:

[0024] S1 First, preliminarily determine whether there is large-scale water loss in the pipe network by whether the cumulative water replenishment volume of the water replenishment pipeline within a unit time t is greater than the allowable leakage volume of the total water volume of the pipe network;

[0025] S2 When it is determined that there is large-scale water loss in the pipe network, it is necessary to further determine according to the pressure drop rate of the water return pipeline.

[0026] On the basis of the above solution, the further determination condition in step S2 is that the pressure drop rate ΔP of the return water pipeline ret / Δt < -3 kPa / min and continues to decrease, and finally it is determined that there is a large-scale water loss phenomenon.

[0027] The beneficial effects of the present invention are as follows:

[0028] Using the system and method of the present invention to determine large-scale water loss can perform automatic monitoring and determination stably for a long time, provide a reliable basis for water loss diagnosis, and reduce labor costs; and control the mass flow error within a very small range, providing more reliable data support for the overall operation of the heat exchange station. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of the system of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] The terms used in the present invention generally have the meanings commonly understood by those of ordinary skill in the art unless otherwise specified.

[0031] The present invention will be further described in detail below with reference to specific embodiments and data. The following embodiments are only for illustrating the present invention and do not limit the scope of the present invention in any way.

[0032] As Figure 1 shown, the present invention provides a system for determining whether the water loss state of a heat exchange station belongs to large-scale water loss,

[0033] including a first temperature sensor 1-1 and a first ultrasonic heat meter 1-2 for measuring the supply water temperature T sup respectively arranged on the supply water pipeline 1 and a first pressure sensor 1-3 for measuring the supply water volume flow Q v,sup in the supply water pipeline 1 and a first pressure sensor 1-3 for measuring the supply water pressure P sup ;

[0034] including a second temperature sensor 2-1 for measuring the return water temperature T ret arranged on the return water pipeline 2, a second ultrasonic heat meter Q for measuring the return water flow in the return water pipeline v,ret 2-2 and a second pressure sensor 2-3 for measuring the return water pressure P ret ;

[0035] further including a third temperature sensor 3-1 for measuring the makeup water temperature T makeup arranged on the makeup water pipeline 3, an ultrasonic water meter 3-2 for measuring the makeup water volume flow Q v,makeup and a pressure sensor for measuring the pressure P in the makeup water pipelinemakeup the third pressure sensor 3-3;

[0036] It further includes an evaluation system 4 for evaluating whether the water loss state belongs to large-scale water loss; the conditions for large-scale water loss are

[0037] wherein,

[0038] are: within a certain time range (from the initial moment 0 to the current moment t), the cumulative mass of water replenished by the system, i.e., Q m,makeup ;

[0039] Q v,makeup is the cumulative volume flow rate of water flowing through measured by the meter within time t; that is, the measured flow rate of the ultrasonic water meter 3-2 within time t;

[0040] ρ makeup is the density of water in the water supply pipeline 3 within time t;

[0041] The time t should be set as a fixed value according to requirements or empirical values before the system is used, such as 1 min or 1 h, and is generally set to 1 h.

[0042] ρ total is the average density of water in the water inlet pipeline 1 and the water return pipeline 2 within time t. When calculating, first calculate the average temperature and average pressure of the water inlet pipeline 1 and the water return pipeline 2 within time t, and then calculate the corresponding density value from the average temperature and average pressure through IAPWS-IF97.

[0043] V total : total water capacity of the pipe network (m 3 ); The total water capacity of the pipe network is the total designed capacity of the secondary network of the entire heat exchange station. It can be calculated by the pipe network volume through the design drawings (applicable to newly built heat exchange stations) or obtained according to past operation data and historical operation experience (applicable to operationally mature heat exchange stations);

[0044] k: leakage rate coefficient (usually 0.5%-2%), and the specific value is set according to past empirical values. For example, setting it to 1% means that according to past experience, the allowable leakage rate of the pipe network is ≤1%, and it is generally set to 1%.

[0045] Taking the density of water in the water supply pipeline 3 as an example for illustration: Since the density of water is a function of temperature and pressure, it is necessary to consider the pressure change value for analysis. For more accuracy, the average temperature and average pressure within time t are used for calculation. When calculating, based on a high-precision model (IAPWS-IF97), specifically:

[0046] ρ makeup = ρ(T makeup , P makeup ) = f(Tmakeup ,P makeup )

[0047] In practical applications, the table lookup method is usually adopted, that is, the density table ρ(T makeup ,P makeup ) is divided into two-dimensional tables according to temperature (0-200°C) and pressure (0.1-10MPa). makeup and P makeup , take the nearest bilinear interpolation in the table, the bilinear interpolation calculation method is a conventional method for those skilled in the art and will not be described in detail here.

[0048] The IAPWS-IF97 (International Association for the properties of Water and Steam, Industrial Formulation 1997) specification provides formulas for calculating various thermodynamic properties of water and steam based on pressure and temperature.

[0049] When it is judged that there is a large-scale water loss through the replenishment amount, it is verified by the pressure change rate of the return water pipeline 2. Specifically, in the time period t (t1-t2), the pressure drop rate of the return water pipeline 2 is ΔP / Δt;

[0050] in:

[0051]

[0052] (1) When ΔP ret When / Δt<-3kPa / min and continues to decrease, it can be judged that a large-scale water loss phenomenon has occurred.

[0053] For the secondary pipe network of the heat exchange station, the pressure drop rate threshold is usually set to a pressure drop of less than 0.015MPa in 5 minutes, that is, -3kPa / min. In the water pipe leakage test, if the pressure drop does not exceed 0.05MPa within 30 minutes, it can be judged as qualified, that is, the pressure drop rate is -1.67kPa / min, there may be leakage. Therefore, setting it to -3kPa / min can avoid frequent false alarms due to normal pressure fluctuations in the pipe network while judging the occurrence of large-scale water loss.

[0054] (2) When ΔP ret / Δt≥-3kPa / min, it can be combined with the operation data to check whether there is instrument failure or new users, and it can also be combined with the supply and return water mass flow and the makeup water mass flow to comprehensively compare and determine whether there is water loss. The specific method is:

[0055] The water volume flow rate Q is measured during the time t.v,sup , the return water volume flow rate Q v,ret , the pressure P of the water supply pipeline sup , the pressure P of the return water pipeline ret , the water temperature T of the water supply network sup , the water temperature T of the return water network ret , by calling the high-precision model IAPWS-IF97, the density ρ of the water in the water supply network under the corresponding working conditions is calculated by the bilinear interpolation method sup and the density ρ of the water in the return water pipeline ret ;

[0056] That is, ρ sup = ρ(T sup , P sup ) = f(T sup , P sup )

[0057] ρ ret = ρ(T ret , P ret ) = f(T ret , P ret )

[0058] The water supply mass flow rate Q under the corresponding working conditions is calculated by the formula m,sup , the return water pipeline mass flow rate Q m,ret

[0059] The specific formula is:

[0060]

[0061] During the same time period t, the difference between the water supply network mass flow rate Q m,sup and the return water pipeline mass flow rate Q m,ret is equal to the makeup water mass flow rate Q m,makeup , then there is Q m，sup ―Q m，ret = Q m，makeup ;

[0062] That is

[0063] If the data is consistent and the makeup water volume increases, it may lead to a decrease in the network pressure due to small-scale leakage, or pressure fluctuations in the network due to new users and the adjustment of the valve opening at the user end; if the data is inconsistent, consider whether there are instrument failures or measurement errors, and check and calibrate the instruments.

[0064] Judged as large-scale water loss by the formula , and when it is judged by pressure that large-scale water loss has not been reached, the possible reasons are as follows:

[0065] 1. Small-scale continuous leakage: The leakage rate is lower than the pressure monitoring sensitivity.

[0066] 2. Sudden increase in user water consumption: Normal water replenishment not caused by water loss (such as new user connection).

[0067] 3. Sensor error: Pressure sensor drift or water replenishment flowmeter error.

[0068] The evaluation system (4) first collects real-time information in the pipeline through temperature, pressure sensors, heat meters and water meters arranged on the water inlet pipeline 1, the water return pipeline 2 and the water replenishment pipeline 3, and then uses the collected information to make a judgment by the above method. The information collection method can be carried out by wired or wireless means, and both of these methods belong to the conventional technical means of those skilled in the art and will not be elaborated here.

[0069] The above is only a preferred embodiment of the present invention, and is not a limitation of the present invention in other forms. Any person skilled in the art may use the technical content disclosed above to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still belong to the protection scope of the technical solution of the present invention.

Claims

1. A system for judging whether the water loss state of a heat exchange station belongs to large-scale water loss, characterized in that Including a first temperature sensor (1-1) respectively arranged on the water supply pipeline (1) for measuring the water supply temperature T sup and a first ultrasonic heat meter (1-2) for measuring the water supply volume flow rate Q in the water supply pipeline (1) v,sup and a first pressure sensor (1-3) for measuring the water supply pressure P sup ; Including a second temperature sensor (2-1) disposed in the return water pipeline (2) for measuring the return water temperature T ret and a second ultrasonic heat meter Q v,ret (2-2) for measuring the return water flow rate in the return water pipeline and a second pressure sensor (2-3) for measuring the return water pressure P ret ; It also includes a third temperature sensor (3-1) disposed on the make-up water pipeline (3) for measuring the make-up water temperature T makeup , an ultrasonic water meter (3-2) for measuring the make-up water volume flow rate Q v,makeup , and a third pressure sensor (3-3) for measuring the pressure P in the make-up water pipeline makeup ; it further includes an evaluation system (4) for evaluating whether the water loss state belongs to large-scale water loss; the condition for large-scale water loss is that the cumulative water replenishment volume of the make-up water pipeline (3) is greater than the allowable leakage volume of the total water volume of the pipe network within unit time t.

2. The system for determining whether the water loss state of a heat exchange station belongs to large-scale water loss according to claim 1, wherein The specific conditions for evaluating the water loss state are: Wherein, Namely: the cumulative mass of the system makeup water within a certain time range; Q v,makeup The cumulative volume flow rate of water flowing through the meter within time t; ρ makeup is the density of water in the make-up water pipeline (3) within time t; ρ total is the average density of water in the inlet pipeline 1 and the return pipeline 2 within the time t; V total： Total water capacity of pipe network (m 3 ); k: leakage rate coefficient.

3. The system for determining whether the water loss state of a heat exchange station belongs to large-scale water loss according to claim 2, characterized in that, When is the case, it is necessary to further determine according to the pressure drop rate of the return water pipeline (2).

4. The system for determining whether the water loss state of a heat exchange station belongs to large-scale water loss according to claim 3, wherein The condition for further determination is that the pressure drop rate ΔP of the return water pipeline (2) ret / Δt < -3 kPa / min and continues to decrease, and finally it is determined that there is a large-scale water loss phenomenon.

5. The use of the system according to any one of claims 1-4, for judging whether the water loss state of a heat exchange station belongs to large-scale water loss.

6. A method for determining whether the water loss state of a heat exchange station belongs to large-scale water loss, characterized in that, Use the system according to any one of claims 1-4.

7. The method for determining whether the water loss state of a heat exchange station belongs to large-scale water loss according to claim 6, characterized in that, It includes the following steps: S1 First, preliminarily determine whether there is large-scale water loss in the pipe network by whether the cumulative water replenishment volume of the make-up water pipeline (3) is greater than the allowable leakage volume of the total water volume of the pipe network within unit time t; S2 When it is determined that there is large-scale water loss in the pipe network, it is necessary to further judge according to the pressure drop rate of the return water pipeline (2).

8. The method for determining whether the water loss state of a heat exchange station belongs to large-scale water loss according to claim 7, characterized in that, The further determination condition in step S2 is that the pressure drop rate ΔP ret / Δt of the return water pipe (2) is < -3 kPa / min and continues to decrease, and finally it is determined that there is a large-scale water loss phenomenon.

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