Open type cooling tower water supply flow balance control method and system

Abstract

The invention provides a water supply flow balance control method and system for an open type cooling tower. The method comprises the steps that S1, the initial opening degree of a bound electric control valve corresponding to a newly-started or newly-closed cooling tower fan is adjusted; s2, the opening degrees of the electric adjusting valves of all the water inlet pipes are adjusted till the detected pressure values of the water inlet pipes are smaller than or equal to the pressure value under the rated flow; s3, calculating the real-time target pressure of each type of cooling tower according to the regulating pressure target value relation mathematical model of the water supply pipe of each type of cooling tower; s4, when the detected pressure value of the water inlet pipe is larger than the real-time target pressure value, the opening degree of the corresponding electric adjusting valve is adjusted to be smaller; when the detected pressure value of the water inlet pipe is smaller than the pressure target value, the opening degree of the electric adjusting valve is increased; the flow balance distribution of each water inlet can be realized, the heat dissipation efficiency of the cooling tower is greatly improved, and the maintenance workload of operation and maintenance personnel is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of open cooling towers, and in particular to a method and system for controlling the water supply flow balance of an open cooling tower. Background Art

[0002] An open cooling tower is a commonly used cooling device in an air conditioning system and is also a key device for ensuring the energy efficiency of the air conditioning system. Many large-scale air conditioning systems use multiple cooling towers. The imbalance in water supply between cooling towers may cause some cooling towers to be replenished with water while some overflow, resulting in waste of water resources. Even worse, the cooling effect may decrease due to the imbalance between different cooling towers. For example, some cooling towers have insufficient water supply, but the power consumed by the fans they operate is the same as that of other simultaneously operating fans, resulting in an excessive air-water ratio and waste of electric energy. Some cooling towers have excessive water supply, causing the supplied water volume to exceed their cooling capacity range and the outlet water temperature to be too high, resulting in an increase in the power consumption of the chiller. In the prior art, CN112857078A discloses a dynamic hydraulic balance adjustment method for a cooling tower group, which uses the pressure difference imbalance rate between each branch pipe and the main pipe to adjust the water supply flow balance of each cooling tower. This method can solve the water supply flow balance problem of a single-supply and single-return air conditioning cooling water system, but it cannot solve the water supply flow balance problem of a cooling tower in a pipe network system with multiple supply and return water paths. For example, there are two or more main water supply pipes. In particular, the air conditioning cooling system of a data center mostly uses a ring network, and the cooling towers are all connected in parallel to the ring network. For example Figure 3 , there are three options for the water in the cooling tower group to enter, namely, entering from inlet A or inlet B or entering from both inlet A and inlet B at the same time. First, in the solution of CN112857078A, the main pipe pressure value is a unique value, and it is easy to calculate the difference and imbalance rate of each water supply branch. However, in Figure 3Among them, there are two main pipe pressure values, and it is not feasible to calculate the pressure difference based on either of them. Because the imbalance rate calculated based on the A main pipe is not applicable to the cooling tower supplied by the B main pipe, and similarly, the imbalance rate calculated based on the B main pipe is not applicable to the cooling tower supplied by the A main pipe. Secondly, there are multiple chillers in the ring network system. Some are close to the A water supply main pipe, and some are close to the B main water inlet pipe. It is uncertain which one or which ones to start. The water resistance from the cooling water pump to the inlet of the tower is also uncertain. For example, the middle cooling tower 3 may be supplied with water from the A line or may also be supplied with water from the B line, and it is impossible to calculate the pressure difference imbalance rate between the branch pipe and the main pipe. Thirdly, if there are cooling towers of different sizes and models in a loop, especially in some large-scale projects, which are all constructed in phases, the cooling towers purchased later may not be of the same model as the originally installed cooling towers, and the diameters of their water supply branch pipes and the heights of their water supply outlets are all different, which brings difficulties to the calculation of the pressure difference imbalance rate. Using the above technologies cannot solve the problem of flow balance between the cooling water inlet pipes in the cooling tower group of the ring network system. There are also some existing technologies that add flow-limiting balance devices. These devices can only ensure that the flow rate of each inlet pipe does not exceed the limited flow rate, and cannot achieve the equal distribution of the flow rate between the inlet pipes. If variable flow operation is adopted for each cooling tower, such as operating at 50% of the flow rate, and the operating flow rate is below the limited flow rate, these flow-limiting balance devices cannot solve the problem of balanced distribution of each inlet pipe at low flow rates. In actual projects, when the number of chillers is adjusted or the position of the operating chiller is adjusted, the maintenance personnel have to adjust the manual water supply valve of the cooling tower every time, which not only increases the workload of the maintenance personnel, but also cannot achieve the balanced distribution of the water supply flow rate between the inlet pipes of the cooling tower group in the ring network system by manual adjustment. Summary of the Invention

[0003] The present invention solves the problem that the prior art cannot achieve the balanced distribution of the inlet pipes, and proposes an open cooling tower water supply flow balance control method and system, which can achieve the balanced distribution of the flow rate at each water inlet, greatly improve the heat dissipation efficiency of the cooling tower, and reduce the maintenance workload of the maintenance personnel.

[0004] To achieve the above object, the following technical solutions are proposed: An open cooling tower water supply flow balance control method, using the above-mentioned open cooling tower water supply flow balance control system, includes the following steps: S1. Determine the start-stop change of the cooling tower, adjust the initial opening degree of the electric control valve bound to the newly started or newly stopped cooling tower fan, open the electric control valve bound to the newly started cooling tower fan to 100% opening degree; open the electric control valve bound to the newly stopped cooling tower fan to 0% opening degree; S2, if there is a water inlet pipe with a detected pressure value greater than the pressure value at the rated flow rate, then reduce the opening degree of the electric control valve until the detected pressure value is less than or equal to the pressure value at the rated flow rate; S3, calculate the real-time target pressure of each type of cooling tower according to the mathematical model of the relationship between the regulating pressure target values of the water supply pipes of each type of cooling tower; S4. When the detected pressure value of the water inlet pipe is greater than the real-time target pressure value, reduce the opening degree of the corresponding electric control valve; when the detected pressure value of the water inlet pipe is less than the pressure target value, increase the opening degree of the electric control valve.

[0005] The present invention dynamically calculates and establishes a mathematical model of the water supply pressure relationship between the water inlet pipes of each type of cooling tower, and adjusts the target pressure values of each water inlet pipe in real time, so that for different types of cooling towers, whether it is a single-way supply and return water pipe network, a multi-way supply and return water pipe network, or a loop water inlet pipe network system, or whether it is a constant flow operation or a variable flow operation, the flow balance distribution of each water inlet can be realized, the heat dissipation efficiency of the cooling tower can be greatly improved, the maintenance workload of the maintenance personnel can be reduced, the method is simple and applicable, and the air conditioning system is more energy-saving.

[0006] Preferably, the construction process of the mathematical model of the relationship between the regulating pressure target values of the water supply pipes of each type of cooling tower is as follows: When the cooling tower models in the same system are the same, the target pressure values of each water supply pipe are the average values of the real-time detected pressure values of each water supply pipe of the operating cooling towers; When there are different types of cooling towers in the same system, first determine the relationship between the target pressure of the water supply pipe between each cooling tower and the cooling tower with the minimum rated flow rate, calculate the real-time target pressure values of other types of cooling towers, and then determine the relationship coefficients of the flow rate and the equivalent resistance relationship between any two different types of cooling towers to the controller.

[0007] Preferably, the process of determining the relationship coefficients of the flow rate and the equivalent resistance relationship between any two different types of cooling towers is as follows: obtain the equivalent resistance coefficients of each type of cooling tower at the rated flow rate; when all the cooling tower models in the same system are the same, the relationship coefficient is equal to 1; when there are different types of cooling towers in the same system, based on the rated flow rate of the cooling tower with the minimum cooling capacity, calculate the relationship coefficients of the flow rates of other types of cooling towers and the relationship coefficients of the equivalent resistance coefficients, and then calculate the relationship coefficients of the flow rates and the equivalent resistance coefficients between any two different types of cooling towers.

[0008] When all the cooling tower models in the same system are the same, since the installation heights of the pressure sensors and the heights of the water inlets are the same, the pipe diameters and installation forms of the water inlet pipes are the same, the S values from each pressure sensor to the water inlet are equal, and from P i = SQ 2It can be known that the relationship coefficient x between the equivalent resistance coefficient S and the flow rate Q among the water inlet pipes of each cooling tower i = 1 and y i = 1.

[0009] Preferably, the process of obtaining the equivalent resistance coefficient of each model of cooling tower under the rated flow rate is as follows: Individually turn on each model of cooling tower and its corresponding water pump, record the pressure values and flow rate values of each water inlet pipe when the cooling tower is operating under the rated flow rate condition, and the equivalent resistance coefficient of each water inlet pipe is the quotient of the pressure value and the flow rate value under the rated flow rate condition.

[0010] When there are different models of cooling towers in the same system, the S values from the pressure sensors on the water inlet pipes of different models of cooling towers to the water inlets are not equal. Select one model of cooling tower as the reference tower. Preferably in the present invention, the rated flow rate Q of the cooling tower with the minimum cooling capacity min is used as the reference.

[0011] The flow rate relationship formula for other models of cooling towers is: The equivalent resistance relationship formula for other models of cooling towers is:

[0010] Preferably, the relationship coefficient of the flow rate of other models of cooling towers is the ratio of the rated flow rate of other models of cooling towers to the rated flow rate of the minimum cooling tower, and the relationship coefficient of the equivalent resistance coefficient of other models of cooling towers is the ratio of the equivalent resistance coefficient of other models of cooling towers to the equivalent resistance coefficient of the minimum cooling tower.

[0012] The flow rate relationship formula for any two different models of cooling towers A and B is: The equivalent resistance relationship formula for any two different models of cooling towers A and B is:

[0013] Preferably, the relationship coefficient of the flow rate between any two different models of cooling towers is the ratio between their rated flow rates; the relationship coefficient of the equivalent resistance coefficient of the flow rate between any two different models of cooling towers is the ratio of their equivalent resistance coefficients.

[0014] Preferably, the S4 further includes the following steps: If, among the water inlet pipes of the cooling tower models that have been turned on, there is an electric control valve whose opening degree has reached 100% but the water supply pressure relationship among the cooling towers is still not satisfied, close the opening degree △M value of the electric control valve of the water inlet pipe of the cooling tower that has not reached 100% opening degree among the cooling towers that are operating, until the water supply pressure relationship is satisfied and the opening degree of the electric valve with the maximum opening degree is between 95% and 100%.

[0015] Preferably, it includes the minimum resistance adjustment step of the electric control valve: Obtain the opening degree of each electric control valve on the water supply inlet pipe and the number M of electric control valves with an opening degree greater than 95% and less than 100%. Determine whether M is greater than or equal to 1. If so, do not perform any cooperation. If not, increase the opening degrees of all electric control valves by Δk, where Δk is the difference between 95% and the maximum opening degree value among the electric control valves on the inlet pipe.

[0016] Minimum resistance adjustment of the electric valve. Read the opening degree of each electric valve in the water supply, and determine the number M of valves with an opening degree greater than 95% among the read electric valves. When M≥1, do not perform any cooperation. When M = 0, find the maximum opening degree K among the electric valves on the effective inlet pipe max value, and increase the opening degrees of all electric valves on the effective inlet pipe by Δk = 95% - K max value.

[0017] An open cooling tower water supply flow balance control system adopts the above-mentioned open cooling tower water supply flow balance control method, including a controller, and electric control valves and pressure sensors sequentially arranged on each inlet pipe of each cooling tower according to the water inlet flow direction. Bind and pair the electric control valve and the pressure sensor on the same inlet pipe, and bind the opening and closing of all electric control valves of the same cooling tower with the cooling tower fan. The controller is electrically connected to a data memory, the data memory is electrically connected to a data collector and an adjustment instruction outputter, the data collector is electrically connected to the pressure sensor and the electric control valve, the adjustment instruction outputter is electrically connected to the electric control valve, and the data memory stores a mathematical relationship model of the adjustment pressure target value relationship for the water supply pipes of each type of cooling tower.

[0018] Preferably, the vertical height of the pressure sensor from the cooling tower water inlet is all H, and the distance between the electric control valve and the pressure sensor is all h.

[0019] The beneficial effects of the present invention are as follows: By dynamically calculating and establishing a mathematical relationship model of the water supply pressure between the inlet pipes of each type of cooling tower, the present invention adjusts the target pressure value of each inlet pipe in real time, enabling different types of cooling towers, whether it is a single-way supply and return water pipe network, a multi-way supply and return water pipe network, a loop inlet pipe network system, or a constant flow operation or variable flow operation, to achieve balanced distribution of the flow rate at each water inlet, greatly improving the heat dissipation efficiency of the cooling tower, reducing the maintenance workload of maintenance personnel, and the method is simple and applicable, making the air conditioning system more energy-efficient. Description of the Drawings

[0020] Figure 1 is a flow chart of the method of the present invention.

[0021] Figure 2 is a structural diagram of the system of the present invention.

[0022] Figure 3It is a schematic diagram of the structure of the water-cooled unit in Embodiment 2.

[0023] Figure 4 It is a schematic diagram of the installation positions of the electric control valve and the pressure sensor of the present invention.

[0024] Figure 5 It is a schematic diagram of the structure of the water-cooled unit in Embodiment 3.

[0025] Wherein: 1. The first chiller; 2. The second chiller; 3. The third chiller; 4. The fourth chiller; 5. The fifth chiller; 11. The first water inlet pipe; 12. The first electric control valve; 13. The first pressure sensor; 14. The second water inlet pipe; 15. The second electric control valve; 16. The second pressure sensor; 33. The third pressure sensor; 36. The fourth pressure sensor; 51. The third water inlet pipe; 52. The third electric control valve; 53. The fifth pressure sensor; 54. The fourth water inlet pipe; 55. The fourth electric control valve; 56. The sixth pressure sensor. Specific embodiments

[0026] Embodiment 1: This embodiment proposes an open cooling tower water supply flow balance control system. Refer to Figure 2 , the control system consists of a pressure sensor, an electric control valve, a data collector, a controller, a data memory and an adjustment instruction outputter. The electric control valve and the pressure sensor are arranged on each water inlet pipe of each cooling tower in sequence according to the water inlet flow direction. On each water inlet pipe of the cooling tower, an electric control valve is installed in sequence according to the water inlet flow direction, and a pressure sensor is installed at a certain distance h from the control valve. The pressure sensor and the electric control valve are connected to the data collector, the electric control valve is also connected to the adjustment instruction outputter, the data collector is connected to the data memory, the controller is connected to the data memory and the adjustment instruction outputter, and the data memory stores a mathematical model of the relationship between the adjustment pressure target values of the water supply pipes of each type of cooling tower. Pressure sensor arrangement. The installation position of the pressure sensor on the water inlet pipe of each tower is below the water inlet of the cooling tower, and the vertical height from the water inlet of the cooling tower is H, and the distance between the electric valve and the sensor is h, as Figure 4 . Pair and bind the electric control valve and the pressure sensor on the same water inlet pipe, and bind the electric valve and the cooling tower fan to open and close simultaneously.

[0027] Determine the equivalent resistance coefficient S i value from the pressure sensor on the water inlet pipe to the water inlet under the rated flow of each type of cooling tower. The method is as follows: separately turn on each type of cooling tower and its corresponding water pump, and adjust the frequency to make the cooling tower operate under the rated flow condition, and record the pressure value P i and the flow value Q i of each water inlet pipe of the tower, and calculate to obtain

[0028] Determine the relationship coefficient x between the equivalent resistance coefficient S and the flow rate Q among the inlet pipes of each type of cooling tower i and y i 。

[0029] 1) When there are different types of cooling towers in the same system, the S values from the pressure sensors on the inlet pipes of different types of cooling towers to the water inlet are not equal. Select one type of cooling tower as the reference tower. In the present invention, it is preferably based on the rated flow rate Q of the cooling tower with the minimum cooling capacity min as the reference

[0030] The flow rate relationship formula for other types of cooling towers is The equivalent resistance relationship formula for other types of cooling towers is The flow rate relationship formula for any two different types of cooling towers A and B is The equivalent resistance relationship formula for any two different types of cooling towers A and B is

[0031] 2) When all the cooling towers in the same system are of the same type, since the installation height of the pressure sensors and the height of the water inlet are the same, and the pipe diameters and installation forms of the inlet pipes are the same, the S values from each pressure sensor to the water inlet are equal. From P i = SQ 2 it can be known that the relationship coefficient x between the equivalent resistance coefficient S and the flow rate Q among the inlet pipes of each cooling tower i = 1 and y i = 1

[0032] Establish a mathematical model for the relationship of the target adjustment pressure values of the inlet pipes of each type of cooling tower

[0033] 1) When there are different types of cooling towers in the same system, first determine the target pressure relationship formula P i = P min y i 2 x i , P min is the target pressure value from the pressure sensor of each inlet pipe of the reference tower to the water inlet, and P i is the real-time target pressure value of each other type of cooling tower. Then determine the target pressure relationship formula P AB = P A y AB 2 x AB between the inlet pipes of any two types of cooling towers A and B. And input it into the controller

[0034] 2) When the cooling tower models in the same system are the same, since the installation positions of each sensor are the same, and the installation heights of the pressure sensors and the inlet heights are the same, and the pipe diameters and installation forms of the inlet pipes are the same, the target pressure values of each inlet pipe are p i which are the real-time detected pressure values of each inlet pipe of the cooling tower in operation.

[0035] This embodiment also proposes a method for controlling the water supply flow balance of an open cooling tower, referring to Figure 1 and specifically including the following steps: Step 1, detect the change in the number of cooling towers started and stopped. Open the corresponding electric control valve of the newly started cooling tower and close the corresponding electric control valve of the newly stopped cooling tower. When the data collector detects that the cooling tower fan is for the newly started cooling tower, the controller opens the corresponding bound electric control valve to 100% opening. When the cooling tower fan is for the newly stopped fan, the corresponding bound electric control valve of the cooling tower is closed to 0% opening.

[0036] Step 2, determine whether there is a pressure value greater than the pressure value under the rated flow rate, and adjust the pressure of all the detected inlet pipes with pressure values greater than the pressure value under the rated flow rate to not greater than the pressure value under the rated flow rate.

[0037] Step 3, determine the real-time target pressure values of each model of cooling tower. According to the detected models of the cooling towers in operation, the controller calculates the real-time target pressures of each model of cooling tower according to the mathematical model of the relationship between the adjusted pressure target values of the water supply pipes of each model of cooling tower that has been determined.

[0038] Step 4, replace the adjusted target pressure value. Input the target pressure value into the data storage area and replace the original target pressure value.

[0039] Step 5, flow regulation. When the detected value is greater than the target pressure value, reduce the opening of the electric control valve; when the pressure value detected by the sensor is less than the pressure target value, increase the opening of the electric control valve; when the opening of the inlet pipe electric valve of a certain cooling tower in the already started cooling tower models has reached 100% and still cannot meet the water supply pressure relationship formula between each tower, reduce the opening of the inlet pipe electric valve of the cooling tower in the cooling towers in operation that have not reached 100% opening, so that the pressures between the inlet pipes of each model meet the target pressure relationship formula.

[0040] Step 6, minimum resistance regulation of the electric valve. Read the opening of each electric valve in the water supply, and judge the number M of valves with an opening greater than 95% and less than 100% among the read electric valves. When M≥1, do not perform any cooperation. When M = 0, find the maximum opening K max value of the electric co-valve on the effective inlet pipe, and increase the opening of all the electric valves on the effective inlet pipes by △k = 95% - K max value. After S seconds, return to Step 1.

[0041] The present invention dynamically calculates and establishes a mathematical relationship model of the water supply pressure between the water inlet pipes of each type of cooling tower, and adjusts the target pressure values of each water inlet pipe in real time, enabling different types of cooling towers, whether it is a single-loop water supply and return pipe network, a multi-loop water supply and return pipe network, or a loop water inlet pipe network system, and whether it is a constant flow operation or a variable flow operation, to achieve a balanced distribution of the flow rate at each water inlet, greatly improving the heat dissipation efficiency of the cooling tower, reducing the maintenance workload of the maintenance personnel, being simple and applicable, and making the air conditioning system more energy-efficient.

[0042] Embodiment 2: On the basis of Embodiment 1, this embodiment describes the same type of cooling tower in the same loop cooling system, and proposes an open cooling tower water supply flow balance control system. The control system consists of a pressure sensor, an electric control valve, a data collector, a controller, a memory, and an adjustment output device. The pressure sensor and the electric control valve are connected to the data collector, the electric control valve is also connected to the adjustment output device, the data collector is connected to the memory, and the controller is connected to the memory and the adjustment output device. Refer to Figure 2 。

[0043] A cooling water system in which all cooling towers in the same cooling water system have the same model, and the water inlet pipe diameters and installation methods are the same. For example Figure 3 In the cooling water loop network system, there are 5 chillers in total, namely the first chiller 1, the second chiller 2, the third chiller 3, the fourth chiller 4, and the fifth chiller 5, corresponding to 5 cooling towers, namely the first cooling tower 111, the second cooling tower 222, the third cooling tower 333, the fourth cooling tower 444, and the fifth cooling tower 555. Among them, the 5 cooling towers have the same model. The diameters and installation forms of the first water inlet pipe 11 and the second water inlet pipe 14 of the first cooling tower 111 are the same. A first electric control valve 12 and a first pressure sensor 13 are installed on the first water inlet pipe 11, and a second electric control valve 15 and a second pressure sensor 16 are installed on the second water inlet pipe 14.

[0044] Install pressure sensors and electric control valves. The installation positions of the first pressure sensor 13 and the second pressure sensor 15 are below the water inlet of the cooling tower, and the vertical height from the lowest point of the inner wall of the horizontal water inlet pipe at the highest point of the cooling tower is 1.5 m.

[0045] Bind the cooling tower fan of the first cooling tower 111 to the pressure sensor and the electric control valve. Pair and bind the first electric control valve 12 on the first water inlet pipe 11 with the first pressure sensor 13, pair and bind the second electric control valve 15 on the second water inlet pipe 14 with the second pressure sensor 16. The first electric control valve 13 and the second electric control valve 16 are turned on and off simultaneously with the cooling tower fan of the first cooling tower 111, and the same operation is performed for other cooling towers.

[0046] This embodiment also proposes a method for controlling the water supply flow balance of an open cooling tower, which specifically includes the following steps: Step 1: Detect the change in the number of cooling towers starting and stopping. Open the corresponding electric control valve of the newly started cooling tower and close the corresponding electric control valve of the newly stopped cooling tower. In this embodiment, it is detected that the first cooling tower 111 is a newly started cooling tower fan, and the corresponding first electric control valve 12 and second electric control valve 15 are both opened to the 100% opening state and fed back to the data collector.

[0047] Step 2: Determine whether there is a pressure value greater than the pressure value under the rated flow rate, and adjust the pressure of all detected inlet pipes with a pressure value greater than the pressure value under the rated flow rate to not greater than the pressure value under the rated flow rate.

[0048] Step 3: The collector reads the pressure data of the corresponding pressure sensors bound to the electric control valves and calculates the target pressure value. In this embodiment, the pressure sensors selected for water supply are the first pressure sensor 13 and the second pressure sensor 16. The pressure value P of the pressure sensor 13 13 = 55 Kpa, and this inlet pipe is in the water supply state. The pressure value P of the pressure sensor 16 16 = 75 Kpa, and the pressure values of other inlet pipes ≤ 1.5 × 9.8 KPa. When the inner diameters of the first inlet pipe 11 and the first inlet pipe 14 of the first cooling tower 111 are the same, the inlet heights are the same, and the installation forms of the inlet pipes are the same, the K values are equal. From P i = KQ 2 it can be seen that because the installation positions of the sensors are the same, to make the flow rate Q equal, it is only necessary that the target pressure values P of the sensors are the same. The target pressure value is

[0049] Step 4: Replace the adjusted target pressure value with 65 KPa. Input the target pressure value into the data storage area and replace the original target pressure value.

[0050] Step 5: Flow regulation. The pressure value P of the first pressure sensor 13 13 = 55 Kpa < 65 kPa, and the first electric control valve 12 has been opened to 98%, so it does not act; the pressure value P of the second pressure sensor 16 16 = 75 Kpa > 65 kPa, and the opening of the second electric control valve 15 is adjusted to be closed. Return to the first step.

[0051] The present invention dynamically calculates and establishes a mathematical relationship model for the water supply pressure between the inlet pipes of cooling towers of various models, and adjusts the target pressure values of each inlet pipe in real time, enabling the flow balance distribution of each water inlet for different models of cooling towers, whether it is a single-loop supply and return pipe network, a multi-loop supply and return pipe network, a loop inlet pipe network system, or a constant-flow operation or variable-flow operation. This significantly improves the heat dissipation efficiency of the cooling tower, reduces the maintenance workload of maintenance personnel, and the method is simple and applicable, making the air-conditioning system more energy-efficient.

[0052] Embodiment 3: On the basis of Embodiment 1, this embodiment will be described with multiple different models of cooling towers in the same loop cooling system, and a water supply flow balance control system for an open cooling tower is proposed. There are multiple cooling towers in the same cooling water system, with different models, and there are also multiple different inlet pipe diameters and installation methods, as Figure 5 shown. There are a total of 5 chillers in this cooling water system, namely the first chiller 1, the second chiller 2, the third chiller 3, the fourth chiller 4, and the fifth chiller 5, corresponding to 5 cooling towers, namely the first cooling tower 111, the second cooling tower 222, the third cooling tower 333, the fourth cooling tower 444, and the fifth cooling tower 555. The first chiller 1 and the second chiller 2 are small-sized units, and the corresponding cooling towers, the first cooling tower 111 and the second cooling tower 222, are small-sized cooling towers; the three chillers of the third chiller 3, the fourth chiller 4, and the fifth chiller 5 have the same rated cooling capacity, and the cooling capacities of the corresponding third cooling tower 333, the fourth cooling tower 444, and the fifth cooling tower 555 are the same. However, due to the phased construction of the project, four cooling towers, namely the first cooling tower 111 to the fourth cooling tower 444, were installed in the first phase, and the fifth cooling tower 555 was installed last. Due to technical improvements and different brands, the external dimensions and the installation form of the inlet pipes of the fifth cooling tower 555 are different from those of the third cooling tower 333 and the fourth cooling tower 444.

[0053] Install pressure sensors and electric control valves. The installation positions of the first pressure sensor 13 and the second pressure sensor 16 are below the water inlet of the first cooling tower 111 of the first chiller 1, and the vertical height of the pressure sensors from the inlet pipe orifice of the cooling tower is 1.5 m. For the third cooling tower 333, the fourth cooling tower 444, and the fifth cooling tower 555, based on the first installed first cooling tower 111, the vertical height of the pressure sensors from the inlet pipe orifice of the cooling tower is H = 1.5 m, and the distance between the first electric control valve 12 and the first pressure sensor 13 and the distance h between the second electric control valve 15 and the second pressure sensor 16 are 0.5 m.

[0054] Pair and bind the third electric control valve 52 on the third water inlet pipe 51 with the fifth pressure sensor 53, and pair and bind the fourth electric control valve 55 on the second water inlet pipe 54 with the sixth pressure sensor 56. The third electric control valve 53 and the fourth electric control valve 56 are turned on and off simultaneously with the cooling tower fan of the first cooling tower 111. Bind the cooling tower fan with the pressure sensor and the electric control valve. Pair and bind the first electric control valve 12 on the first water inlet pipe 11 of the first cooling tower 111 with the first pressure sensor 13. Pair and bind the second electric control valve 15 on the second water inlet pipe 14 of the first cooling tower 111 with the second pressure sensor 16. Bind the first electric control valve 12 and the second electric control valve 15 with the cooling tower fan of the first cooling tower 111 to implement simultaneous on and off, and other cooling towers are processed in the same way.

[0055] Determine the coefficients x and y: First step, separately turn on the first cooling tower 111 and its corresponding water pump, and adjust the frequency so that the water pump operates at the rated flow rate Q min Under the working condition, according to the method of Embodiment 1, when the pressures detected by the first pressure sensor 13 and the second pressure sensor 16 are equal, record the pressure value P min .

[0056] Second step, in the same way, separately turn on the third cooling tower 333 and its corresponding water pump, and adjust the frequency so that the water pump operates at the rated flow rate Q3. According to the method of Embodiment 1, when the pressures detected by the third pressure sensor 33 and the fourth pressure sensor 36 are equal, record the pressure value P3.

[0057] Third step, in the same way as the second step, separately turn on the cooling tower 5 and its corresponding water pump, and adjust the frequency so that the water pump operates at the rated flow rate Q5. According to the method of Embodiment 1, when the pressures of the fifth pressure sensor 53 and the sixth pressure sensor 56 are equal, record the pressure value P5.

[0058] When the first cooling tower 111 and the third cooling tower 333 operate simultaneously, it is desired to distribute the flow rates of the two towers in proportion to the rated conditions. Therefore, the relational expression is obtained.

[0059]

[0060] When the first cooling tower 111, the third cooling tower 333 and the fifth cooling tower 555 operate simultaneously, it is desired to distribute the flow rates of the three towers in proportion to the rated conditions. Therefore, the relational expression is obtained.

[0061] There is a relational expression P min = S min Q min 2 and P5 = S3Q3 2, substitute the above recorded data into

[0062] Calculate the target pressure value: Write P3 as S min and Q min in the relational expression, and obtain P5 = x2y2 2 P min , P3 = x1y1 2 P min .

[0063] Similarly, the relational expression between the target pressure value P5 of the fifth cooling tower 555 and the target pressure value P3 of the third cooling tower 333 can be obtained, P5 = x3y3 2 P3.

[0064] This embodiment also proposes an open cooling tower water supply flow balance control method, which specifically includes the following steps: Step 1 Detect whether there is a cooling tower with a newly started fan or a cooling tower fan that has been newly shut down. In this embodiment, the first cooling tower 111 and the fifth cooling tower 555 are currently detected as newly started cooling towers.

[0065] Step 2 Open the electric control valves corresponding to the newly started cooling tower fans to the 100% state, do not act on the electric control valves of the started or unstarted cooling towers, close the electric control valves corresponding to the just-shut-down cooling tower, and feedback to the data collector. Open the first electric control valve 12 and the second electric control valve 14 corresponding to the first cooling tower 111 to the 100% opening state, and feedback to the data collector. Open the third electric control valve 52 and the fourth electric control valve 55 corresponding to the fifth cooling tower 555 to the 100% opening state, and feedback to the data collector.

[0066] Step 3 The collector reads the pressure data of the pressure sensors bound to the electric valves. In this embodiment, select the pressure sensors that are supplying water as the first pressure sensor 13, the second pressure sensor 16, the fifth pressure sensor 53, and the sixth pressure sensor 56. Assume the detected value is P 13 , P 16 , P 53 , P 56 . Calculate the average value P1 of the first cooling tower 111 as.

[0067] P1 = (P 13 + P 16 ) / 2; Calculate the target pressure value P5 of the fifth cooling tower 555 as.

[0068] P5 = (P 53 + P 56 ) / 2.

[0069] Target pressure relationship between the first cooling tower 111 and the fifth cooling tower 555: P5 = x2y2 2 P1 Step 4, replace the adjusted target pressure value. Input the target pressure value into the data storage area and replace the original target pressure value.

[0070] Step 5, first determine whether there is a pressure value exceeding the pressure value under the rated flow rate. First, adjust the pressure values of the water inlet pipes of all pressure values exceeding the pressure value under the rated flow rate to the rated pressure value. In this embodiment, P in the first cooling tower 111 13 , P 16 The detected value is compared with P under the rated flow rate min . If P in 13 and P 16 Any one value is greater than P min , first close the first electric control valve 12 and the second electric control valve 15 to make P 13 , P 16 The pressure is less than or equal to P min .

[0071] Step 6, adjust the flow rate of each water inlet pipe. Judge the values of the fifth pressure sensor 53 and the sixth pressure sensor 56. If it is greater than x2y2 2 P1 average, then close the third electric control valve 52 and the fourth electric control valve 55. If it is less than x2y2 2 P 1平均 , then open the third electric control valve 52 and the fourth electric control valve 55. If the third electric control valve 52 and the fourth electric control valve 55 have been opened to 100% opening and are still less than x2y2 2 P 1平均 , then close the first electric control valve 12 and the second electric control valve 15 of the first cooling tower 111 to make the detected pressure values of each water inlet pipe reach the target value. After M seconds, return to Step 1.

[0072] The present invention dynamically calculates and establishes a mathematical relationship model of the water supply pressure between the water inlet pipes of each type of cooling tower, and adjusts the target pressure value of each water inlet pipe in real time, so that for different types of cooling towers, whether it is a single - path supply - return water pipe network, a multi - path supply - return water pipe network, or a loop water inlet pipe network system, and whether it is a constant - flow operation or a variable - flow operation, the flow balance distribution of each water inlet can be achieved, greatly improving the heat dissipation efficiency of the cooling tower, reducing the maintenance workload of the maintenance personnel. The method is simple and applicable, making the air - conditioning system more energy - efficient.

Claims

1. A method for balancing the water supply flow of an open cooling tower, characterized in that: The following steps are involved: S1. Determine the start and stop changes of the cooling tower, and adjust the initial opening of the bound electric regulating valve corresponding to the newly opened or closed cooling tower fan; S2, if there is a water inlet pipe whose detected pressure value is greater than the pressure value at the rated flow rate, reduce the opening of the electric regulating valve until the detected pressure value is less than or equal to the pressure value at the rated flow rate; S3, calculating the real-time target pressure of each type of cooling tower according to the mathematical relationship model of the target value of the pressure adjustment of the water supply pipe of each type of cooling tower; S4. When the detected pressure value of the water inlet pipe is greater than the real-time target pressure value, reduce the opening of the corresponding electric regulating valve; when the detected pressure value of the water inlet pipe is less than the pressure target value, increase the opening of the electric regulating valve.

2. The method for controlling the water flow balance of an open cooling tower according to claim 1, characterized in that: The construction process of the mathematical relationship model of the target value relationship of the regulating pressure of the water supply pipe of each type of cooling tower is as follows: When the cooling towers of the same system are of the same model, the target pressure value of each water supply pipe is the average of the real-time pressure detection values ​​of each water supply pipe of the operating cooling tower; When the same system has cooling towers of different models, first determine the target pressure relationship of the water supply pipe between each cooling tower and the cooling tower with the minimum rated flow rate, calculate the real-time target pressure value of other cooling towers, and then determine the relationship coefficient of the flow rate and the relationship coefficient of the equivalent resistance relationship between any two cooling towers of different models to the controller.

3. The method for controlling the water flow balance of an open cooling tower according to claim 1, characterized in that: The S4 further comprises the following steps: If the water inlet pipe in the cooling tower model has been opened, and the opening of the electric regulating valve has reached 100%, but the water supply pressure relationship between the cooling towers is still not met, close the opening △M value of the electric regulating valve of the cooling tower water inlet pipe that has not reached 100% in the running cooling tower until the water supply pressure relationship is met and the maximum opening electric valve is opened between 95% and 100%.

4. A method for balancing water flow in an open cooling tower according to any one of claims 1 to 3, characterized in that: Including the minimum resistance adjustment steps of the electric control valve: Obtain the opening of each electric regulating valve on the water inlet pipe and the number M of electric regulating valves whose opening is greater than 95% and less than 100%, and determine whether M is greater than or equal to 1. If so, do not perform any operation; if not, increase the opening of the electric regulating valve by △k, where △k is the difference between 95% and the maximum opening value of the electric regulating valve on the water inlet pipe.

5. The method for controlling the water flow balance of an open cooling tower according to claim 2, wherein: The process of determining the relationship coefficient of the flow rate and the relationship coefficient of the equivalent resistance relationship between any two cooling towers of different models is as follows: the equivalent resistance coefficient of each model of cooling tower is obtained at the rated flow rate; when all cooling towers in the same system are of the same model, the relationship coefficient is equal to 1; when there are cooling towers of different models in the same system, the rated flow rate of the cooling tower with the smallest cooling capacity is used as a reference to calculate the relationship coefficient of the flow rate of other models of cooling towers and the relationship coefficient of the equivalent resistance coefficient, and then the relationship coefficient of the flow rate and the relationship coefficient of the equivalent resistance coefficient between any two cooling towers of different models are calculated.

6. The method for controlling the water flow balance of an open cooling tower according to claim 5, characterized in that: The process of obtaining the equivalent resistance coefficient of each type of cooling tower at rated flow is as follows: Start each type of cooling tower and its corresponding water pump separately, and record the pressure and flow value of each water inlet pipe when the cooling tower is operating at rated flow condition. The equivalent resistance coefficient of each water inlet pipe is the quotient of the pressure value and the flow value under rated flow condition.

7. A method for controlling the water flow balance of an open cooling tower according to claim 5 or 6, characterized in that: The relationship coefficient of the flow rate of other types of cooling towers is the ratio of the rated flow rate of other types of cooling towers to the rated flow rate of the minimum cooling tower, and the relationship coefficient of the equivalent resistance coefficient of other types of cooling towers is the ratio of the equivalent resistance coefficient of other types of cooling towers to the equivalent resistance coefficient of the minimum cooling tower.

8. The method for controlling the water flow balance of an open cooling tower according to claim 7, wherein: The relationship coefficient between the flow rates of two cooling towers of any different models is the ratio between their rated flow rates; the relationship coefficient between the equivalent resistance coefficients of two cooling towers of any different models is the ratio between their equivalent resistance coefficients.

9. An open cooling tower water supply flow balance control system, using the open cooling tower water supply flow balance control method according to claim 1, characterized in that: It includes a controller and electric regulating valves and pressure sensors arranged in sequence on each water inlet pipe of each cooling tower according to the direction of water flow. The electric regulating valves and pressure sensors on the same water inlet pipe are bound and paired, and all the electric regulating valves of the same cooling tower are bound to the cooling tower fan for the same opening and closing. The controller is electrically connected to a data storage device, the data storage device is electrically connected to a data collector and a regulating instruction output device, the data collector is electrically connected to the pressure sensor and the electric regulating valve, the regulating instruction output device is electrically connected to the electric regulating valve, and the data storage device stores a mathematical relationship model of the target value of regulating pressure of water supply pipes of various types of cooling towers.

10. The open cooling tower water supply flow balance control system according to claim 9, characterized in that: The vertical height between the pressure sensor and the water inlet of the cooling tower is H, and the distance between the electric regulating valve and the pressure sensor is h.

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