Method for determining pipe network hydraulic disorder based on water supply and return water temperature difference

Abstract

The application provides a method for determining pipe network hydraulic disorder degree based on supply and return water temperature difference, which comprises the following steps: obtaining a plurality of parameters related to pipe network affecting pipe network hydraulic disorder degree in a specific period during heat supply process, calculating the temperature difference of hot water flowing through the pipe network and the supply and return water temperature difference of each branch pipe network in the whole pipe network, determining the average temperature difference of the whole pipe network and the hydraulic disorder degree according to the supply and return water temperature difference of each branch pipe network, and obtaining the hydraulic disorder degree of the whole pipe network. The application determines the hydraulic disorder degree of the whole pipe network and branch network according to the actual heat utilization condition and heat supply scheme of different pipe networks, and thus is not limited to the heat supply design working condition of the pipe network, can intuitively reflect the hydraulic working condition of the pipe network, is more suitable for different pipe network systems, has higher accuracy, and has important value for guiding the front-line staff of the heat supply company to regulate and control the flow of the pipe network.

Description

Technical Field

[0001] This invention belongs to the field of heating system technology, specifically relating to a method for determining hydraulic imbalance in a pipe network based on the temperature difference between supply and return water. Background Technology

[0002] In a heating system, heat is transported from the heat source to various heat exchange stations via a primary pipe network. The hot water, after heat exchange, is then transported to different building users via a secondary pipe network. During the actual operation of the heating network, due to varying resistance, the available pressure differs at different locations within the network, resulting in significant differences in flow rate. This frequently leads to an imbalance where users at the front end of the network experience "overheating" while users at the back end experience "undercooling." The more complex the pipe network, the more severe this hydraulic imbalance becomes. Therefore, maintaining the hydraulic balance of the pipe network is crucial for the heating system.

[0003] Currently, the commonly used method for determining hydraulic misalignment in heating systems is to calculate the ratio of the actual flow rate to the design flow rate. However, in actual engineering projects, limitations in pipeline design, construction, valve and equipment types, and installation can cause the pipeline to operate outside of its design specifications, resulting in discrepancies between actual and design flow rates. Furthermore, achieving accurate metering requires the pipeline to operate under its design conditions. Therefore, this traditional method for calculating hydraulic misalignment is not applicable to real-world engineering projects.

[0004] Furthermore, the methods described above measure the hydraulic misalignment of a single pipe. In actual heating systems, there are dozens or even hundreds of branch pipes, some interconnected and some operating independently, making the internal structure extremely complex. Therefore, existing hydraulic misalignment methods are not very adaptable to larger heating systems, and the hydraulic misalignment determined using these methods is not accurate.

[0005] Therefore, determining the hydraulic misalignment of different heating companies and heat exchange stations is crucial for ensuring the operational quality and management of the heating network! In short, a method is urgently needed to determine the overall hydraulic misalignment of the heating network! Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, this invention provides a method for determining hydraulic misalignment based on the supply and return water temperature difference. The technical problem to be solved by this invention is achieved through the following technical solution:

[0007] The present invention provides a method for determining hydraulic misalignment in a pipe network based on the temperature difference between supply and return water, comprising:

[0008] During the heat energy supply process within a predetermined time period, the cumulative heat consumption, cumulative flow rate of the branch pipe network, start time of hot water flowing through the heat meter, end time of hot water flowing through the flow meter, density of hot water, and specific heat capacity of hot water are obtained.

[0009] For each branch network, based on the cumulative heat consumption, cumulative flow consumption, start time and end time of each branch network, density of hot water and specific heat capacity of hot water, the supply and return water temperature difference of the branch network is calculated using the branch network temperature difference calculation formula.

[0010] The average temperature difference of the entire network is determined based on the supply and return water temperature difference of each branch network.

[0011] The hydraulic imbalance of each branch pipe network is determined based on the average temperature difference of the entire pipe network.

[0012] The hydraulic imbalance of the entire network is determined based on the hydraulic imbalance of each branch network.

[0013] The formula for calculating the temperature difference in the branch pipe network is:

[0014] The formula for calculating the hydraulic misalignment of each branch network is as follows:

[0015]

[0016] The hydraulic outage of the entire pipeline network is represented as:

[0017]

[0018] Where, ΔT i Q represents the temperature difference between the supply and return water flowing through the branch pipe network, expressed in °C. i The cumulative heat loss of the heat meter is expressed in GJ; τ represents time, and dτ represents the period; c represents the specific heat capacity of the hot water, c = 4.2 × 10⁻⁶. 3 J / (kg·℃); ρ represents the density of the hot water flowing through the pipe network, ρ=1000kg / m³ 3 ; c represents the specific heat capacity of hot water, c = 4178 J / (kg·℃); V sj This represents the volumetric flow rate of hot water flowing through the branch pipe network, expressed in m³ / s. 3 / h; τ1 represents the start time of hot water flowing through the branch pipe network; τ2 represents the end time of hot water flowing through the branch pipe network; ΔT represents the average temperature difference of the entire pipe network, expressed in °C. i The supply and return water temperature difference for the i-th branch network is expressed in °C; δ i For the hydraulic misalignment of the i-th branch network, δ n This is the hydraulic misalignment of the nth branch network.

[0019] Optionally, after determining the hydraulic imbalance of each branch pipe network based on the average temperature difference of the entire pipe network, the method for determining the hydraulic imbalance of the pipe network also includes:

[0020] For each branch network, the hot water flow rate entering the branch network is adjusted according to the magnitude of the hydraulic imbalance in that branch network.

[0021] Optionally, for each branch network, the hot water flow rate entering that branch network may be adjusted according to the magnitude of the hydraulic imbalance, including:

[0022] For each branch network, the hydraulic imbalance of the branch network is divided into intervals according to its size. When the hydraulic imbalance of the branch network is in the appropriate interval, it means that the hot water flow rate allocated to the branch network is appropriate.

[0023] When the hydraulic imbalance of the branch network is less than the lower limit of the suitable range, it indicates that the hot water flow rate allocated to the branch network is too small. In this case, the control valve is opened wider to adjust and increase the hot water flow rate entering the branch network.

[0024] When the hydraulic imbalance of the branch network is greater than the upper limit of the suitable range, it indicates that the hot water flow allocated to the branch network is too large. In this case, the control valve is closed to reduce the hot water flow entering the branch network.

[0025] The suitable range is [0.8, 1.2].

[0026] Optionally, for each branch network, the hydraulic imbalance of the branch network is divided into intervals according to its size. When the hydraulic imbalance of the branch network is within a suitable interval, it means that the hot water flow rate allocated to the branch network is suitable, including:

[0027] For each branch network, the hydraulic displacement of the branch network is divided into intervals according to its size. When the hydraulic displacement of the branch network is in a suitable interval, it is further determined whether the hydraulic displacement of the branch network is in a suitable larger interval or a suitable smaller interval.

[0028] If the hydraulic imbalance of the branch network is located in the range of excessively large, it indicates that the hot water flow rate allocated to the branch network is excessively large.

[0029] If the hydraulic imbalance of the branch network is located in the range of a suitable small value, it means that the hot water flow rate allocated to the branch network is suitable to be small.

[0030] If the hydraulic misalignment of the branch network is neither in the range of the larger suitable range nor the range of the smaller suitable range, it means that the hot water flow rate allocated to the branch network is most suitable.

[0031] The suitable larger interval is (1, 1.2], and the suitable smaller interval is [0.8, 1].

[0032] The average temperature difference of the entire pipe network is expressed as:

[0033]

[0034] Where n is the total number of branch pipe networks.

[0035] This invention provides a method for determining hydraulic imbalance in a pipe network based on the supply and return water temperature difference. By acquiring multiple parameters related to the pipe network that may affect hydraulic imbalance during the supply of heat energy within a specific time period, the method calculates the temperature difference of hot water flowing through the network and the supply and return water temperature differences of each branch pipe within the entire network. Based on the supply and return water temperature differences of each branch pipe, the average temperature difference and hydraulic imbalance of the entire network are determined, thus identifying the overall hydraulic imbalance of the network. This invention determines the hydraulic imbalance of the entire network and its branch pipes based on the actual heat consumption and heating scheme of different networks. Therefore, it is not limited by the heating design conditions of the network, providing a direct reflection of the network's hydraulic condition. Furthermore, by using multiple network parameters, it is more adaptable to different network systems and offers higher accuracy. This method is of significant value in providing targeted guidance to frontline heating company staff on how to regulate network flow.

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0037] Figure 1 This is a flowchart illustrating a method for determining hydraulic misalignment in a pipe network based on the temperature difference between supply and return water, provided by the present invention. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0039] like Figure 1 As shown, the method for determining hydraulic misalignment in a pipe network based on the temperature difference between supply and return water provided by this invention includes:

[0040] S1, during the heat energy supply process within a predetermined time period, obtain the cumulative heat consumption, cumulative flow rate of each branch pipe network, start time of hot water flowing through the heat meter, end time of hot water flowing through the flow meter, density of hot water, and specific heat capacity of hot water.

[0041] S2, for each branch network, based on the cumulative heat consumption, cumulative flow consumption, start time and end time of each branch network, density of hot water and specific heat capacity of hot water, use the branch network temperature difference calculation formula to calculate the supply and return water temperature difference of the branch network.

[0042] S3, determine the average temperature difference of the entire network based on the supply and return water temperature difference of each branch network;

[0043] S4. Determine the hydraulic imbalance of each branch network based on the average temperature difference of the entire network.

[0044] S5, determine the hydraulic misalignment of the entire network based on the hydraulic misalignment of each branch network;

[0045] The formula for calculating the temperature difference in the branch pipe network is:

[0046] The hydraulic outage of the entire pipeline network is represented as:

[0047]

[0048] The average temperature difference of the entire pipe network is expressed as:

[0049]

[0050] Where ΔT represents the temperature difference between the supply and return water flowing through the branch pipe network, in °C; Q i The cumulative heat loss of the heat meter is expressed in GJ; τ represents time, and dτ represents the period; c represents the specific heat capacity of the hot water, c = 4.2 × 10⁻⁶. 3 J / (kg·℃); ρ represents the density of the hot water flowing through the pipe network, ρ=1000kg / m³ 3 ; c represents the specific heat capacity of hot water, c = 4178 J / (kg·℃); V sj This represents the volumetric flow rate of hot water flowing through the branch pipe network, expressed in m³ / s. 3 / h; τ1 represents the start time of hot water flowing through the branch pipe network; τ2 represents the end time of hot water flowing through the branch pipe network; ΔT represents the average temperature difference of the entire pipe network. n Let δ be the temperature difference between the supply and return water of the nth branch network. n Let n be the hydraulic misalignment of the nth branch network, where n is the total number of branch networks.

[0051] This invention provides a method for determining the hydraulic imbalance of a pipe network based on the supply and return water temperature difference. By acquiring multiple parameters of the pipe network during a specific time period during the supply of heat energy, including cumulative heat consumption, cumulative flow rate, start time of hot water flowing through the heat meter, end time of hot water flowing through the flow meter, density of the hot water, and specific heat capacity of the hot water, the method calculates the temperature difference of the hot water flowing through the pipe network and the supply and return water temperature difference of each branch pipe network. Based on the supply and return water temperature difference of each branch pipe network, the average temperature difference of the entire pipe network is determined. Based on the average temperature difference of the entire pipe network, the hydraulic imbalance of each branch pipe network is determined. Based on the hydraulic imbalance of each branch pipe network, the hydraulic imbalance of the entire pipe network is determined, thereby determining the hydraulic imbalance of the entire pipe network. This invention determines the hydraulic imbalance of the entire pipeline network and its branches based on the actual heat consumption and heating scheme of different pipeline networks. Therefore, it is not limited by the heating design conditions of the pipeline network, and can intuitively reflect the hydraulic conditions of the pipeline network. Moreover, it is based on multiple parameters of the pipeline network, making it more adaptable to different pipeline network systems and more accurate. It is of great value in providing targeted guidance to front-line employees of heating companies on how to regulate the flow of the pipeline network.

[0052] As an optional embodiment of the present invention, after determining the hydraulic misalignment of each branch pipe network based on the average temperature difference of the entire pipe network, the method for determining the hydraulic misalignment of the pipe network further includes:

[0053] For each branch network, the hot water flow rate entering the branch network is adjusted according to the magnitude of the hydraulic imbalance in that branch network.

[0054] As an optional embodiment of the present invention, adjusting the hot water flow rate entering each branch pipe network according to the magnitude of the hydraulic imbalance of that branch pipe network includes:

[0055] Step a: For each branch network, divide the hydraulic imbalance of the branch network into intervals according to its size. When the hydraulic imbalance of the branch network is in the appropriate interval, it means that the hot water flow rate allocated to the branch network is appropriate.

[0056] It is understandable that when the hot water flow rate is appropriate, it may be too high or too low. In this case, there is no need to adjust the hot water flow rate during actual operation.

[0057] Step b: When the hydraulic imbalance of the branch network is less than the lower limit of the suitable range, it indicates that the hot water flow rate allocated to the branch network is too small. Then, the control valve is opened wider to adjust and increase the hot water flow rate entering the branch network.

[0058] Step c: When the hydraulic imbalance of the branch network is greater than the upper limit of the suitable range, it indicates that the hot water flow allocated to the branch network is too large. In this case, the control valve is closed to reduce the hot water flow entering the branch network.

[0059] The undetermined suitable range is [0.8, 1.2], which can be set and adjusted according to the actual situation.

[0060] As an optional embodiment of the present invention, for each branch network, the hydraulic displacement of the branch network is divided into intervals according to its size. When the hydraulic displacement of the branch network is within a suitable interval, it indicates that the hot water flow rate allocated to the branch network is suitable, including:

[0061] Step a1: For each branch network, divide the hydraulic displacement of the branch network into intervals according to its size. When the hydraulic displacement of the branch network is in a suitable interval, continue to determine whether the hydraulic displacement of the branch network is in a suitable larger interval or a suitable smaller interval.

[0062] Step a2: If the hydraulic imbalance of the branch network is located in the range of suitable excess, it indicates that the hot water flow rate allocated to the branch network is suitable excess.

[0063] Step a3: If the hydraulic imbalance of the branch network is located in the range of a suitable small value, it means that the hot water flow rate allocated to the branch network is suitable to be small.

[0064] Step a4: If the hydraulic misalignment of the branch network is neither in the range of the larger suitable range nor the range of the smaller suitable range, it means that the hot water flow rate allocated to the branch network is most suitable.

[0065] The suitable larger range is (1, 1.2), and the suitable smaller range is [0.8, 1). The suitable larger and smaller ranges are set according to the actual situation, and of course, they can be fine-tuned according to different pipeline networks.

[0066] The following describes the specific process by which the present invention determines and adjusts the hydraulic imbalance of the branch network.

[0067] Based on the above principles for calculating hydraulic displacement, this invention calculates the hydraulic displacement δ of each branch network. i The size of the hydraulic displacement of the pipeline network is used to divide the network into five intervals:

[0068] First interval: When hydraulic displacement δ i In the state of 0<δ i When the calculated temperature difference is ≤1.2, it means that the calculated temperature difference of this branch pipe network is lower than the average temperature difference of the entire pipe network. This indicates that the flow rate allocated to this branch network is appropriately too high.

[0069] Second interval: When hydraulic displacement δ i In the range of 0.8≤δ i When the calculated temperature difference is less than 1, it means that the calculated temperature difference of this branch pipe network is higher than the average temperature difference of the entire pipe network. This indicates that the flow rate allocated to this branch network is appropriately small.

[0070] Third interval: When hydraulic displacement δ i At δ i When the value is less than 0.8, the calculated temperature difference of this branch pipe network is much higher than the average temperature difference of the entire pipe network. This indicates that the flow rate allocated to this branch network is too low, and the valve should be opened wider in this case.

[0071] Fourth interval: When hydraulic displacement δ i At δ i When the calculated temperature difference is greater than 1.2, it means that the calculated temperature difference of this branch network is much lower than the average temperature difference of the entire network. This indicates that the flow rate allocated to this branch network is too high, and the valve should be closed in this case.

[0072] Fifth interval: When hydraulic power is out of control i When = 1, the calculated temperature difference of this branch pipe network is equal to the average temperature difference of the entire pipe network. This indicates that the flow rate allocated to this branch network is most suitable.

[0073] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for determining hydraulic imbalance in a pipe network based on the temperature difference between supply and return water, characterized in that, include: During the heat energy supply process within a predetermined time period, the cumulative heat consumption, cumulative flow rate of the branch pipe network, start time of hot water flowing through the heat meter, end time of hot water flowing through the flow meter, density of hot water, and specific heat capacity of hot water are obtained. For each branch network, the supply and return water temperature difference is calculated using the branch network temperature difference calculation formula based on the cumulative heat consumption, cumulative flow consumption, start time of each branch network, end time, density of hot water, and specific heat capacity of hot water. The average temperature difference of the entire network is determined based on the supply and return water temperature difference of each branch network. The hydraulic imbalance of each branch pipe network is determined based on the average temperature difference of the entire pipe network. The hydraulic imbalance of the entire network is determined based on the hydraulic imbalance of each branch network. The formula for calculating the temperature difference in the branch pipe network is: The formula for calculating the hydraulic misalignment of each branch network is as follows: The hydraulic outage of the entire pipeline network is represented as: in, This indicates the temperature difference between the supply and return water as hot water flows through the branch pipe network, expressed in °C. This indicates the cumulative heat consumption of the heat meter, expressed in GJ. Indicates time, The period is represented by c; the specific heat capacity of the hot water is represented by c. J / (kg∙℃); This indicates the density of hot water flowing through the pipe network. ; The specific heat capacity of hot water is expressed as c = 4178 J / (kg∙℃). This represents the volumetric flow rate of hot water flowing through the branch pipe network, expressed in m³ / s. 3 / h; Indicates the start time of hot water flow through the branch pipe network; Indicates the end time of hot water flow through the branch pipe network; The average temperature difference of the entire pipe network is expressed in °C. The supply and return water temperature difference for the i-th branch network is expressed in °C. For the hydraulic misalignment of the i-th branch network, For the hydraulic misalignment of the nth branch network; After determining the hydraulic misalignment of each branch pipe network based on the average temperature difference of the entire pipe network, the method for determining the hydraulic misalignment of the pipe network further includes: For each branch network, the hot water flow rate entering the branch network is adjusted according to the magnitude of the hydraulic imbalance in that branch network.

2. The method for determining hydraulic imbalance in a pipeline network according to claim 1, characterized in that, The adjustment of the hot water flow rate into each branch pipe network according to the magnitude of the hydraulic imbalance in that branch pipe network includes: For each branch network, the hydraulic imbalance of the branch network is divided into intervals according to its size. When the hydraulic imbalance of the branch network is in the appropriate interval, it means that the hot water flow rate allocated to the branch network is appropriate. When the hydraulic imbalance of the branch network is less than the lower limit of the suitable range, it indicates that the hot water flow rate allocated to the branch network is too small. In this case, the control valve is opened wider to adjust and increase the hot water flow rate entering the branch network. When the hydraulic imbalance of the branch network is greater than the upper limit of the suitable range, it indicates that the hot water flow rate allocated to the branch network is too large. In this case, the control valve is closed to reduce the hot water flow rate entering the branch network. The suitable range is [0.8, 1.2].

3. The method for determining hydraulic misalignment in a pipeline network according to claim 1, characterized in that, For each branch network, the hydraulic displacement of the branch network is divided into intervals according to its size. When the hydraulic displacement of the branch network is within a suitable interval, it means that the hot water flow rate allocated to the branch network is suitable, including: For each branch network, the hydraulic displacement of the branch network is divided into intervals according to its size. When the hydraulic displacement of the branch network is located in the appropriate interval, it is further determined whether the hydraulic displacement of the branch network is located in the appropriate larger interval or the appropriate smaller interval. If the hydraulic imbalance of the branch network is located in the range of excessively large, it indicates that the hot water flow rate allocated to the branch network is excessively large. If the hydraulic imbalance of the branch network is located in the range of a suitable small value, it means that the hot water flow rate allocated to the branch network is suitable to be small. If the hydraulic misalignment of the branch network is neither in the range of the larger suitable range nor the range of the smaller suitable range, it means that the hot water flow rate allocated to the branch network is most suitable. The suitable larger interval is (1, 1.2], and the suitable smaller interval is [0.8, 1].

4. The method for determining hydraulic imbalance in a pipe network according to claim 1, characterized in that, The average temperature difference of the entire pipe network is expressed as: Where n is the total number of branch pipe networks.

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