Control method of cooling water system

Abstract

The invention relates to the technical field of cooling water systems, particularly provides a control method of a cooling water system, and aims to solve the problem that the accuracy and the stability of an approximation value of a cooling water system in the prior art cannot be considered at the same time. In order to achieve the purpose, the control method of the cooling water system comprises the steps that an outdoor wet bulb temperature value is obtained; according to the wet bulb temperature value, determining a preset temperature interval in which the wet bulb temperature value falls; obtaining an outlet water temperature value; under the condition that the difference value of the outlet water temperature values obtained at the interval of the set time length value is smaller than the set temperature difference value, whether the wet bulb temperature value still falls into the temperature interval or not is judged; and under the condition that the wet bulb temperature value still falls into the temperature interval, determining an approximation value of the temperature interval. The approximation value is determined in the stable state, and the approximation value only corresponds to the current temperature interval, so that the determined approximation value can give consideration to accuracy and stability at the same time.

Description

Technical Field

[0001] This invention relates to the field of cooling water system technology, and specifically provides a control method for a cooling water system. Background Technology

[0002] In the cooling water system, the cooling tower fan creates forced airflow, which exchanges heat with the cooling water carrying waste heat inside the cooling tower, thereby lowering the cooling water to the target temperature, while the waste heat is carried away by the air; the cooling pump is used to provide power for the circulation of cooling water in the cooling water system.

[0003] When a cooling water system is operating, it is usually necessary to set a target outlet water temperature for the cooling tower. The frequency of the cooling tower fan and cooling pump is then adjusted and controlled based on this target temperature to achieve better energy savings. However, the target outlet water temperature is calculated using wet-bulb temperature and an approximation value. Current methods for obtaining the approximation value cannot simultaneously guarantee accuracy and stability, thus affecting both the accuracy and stability of the target outlet water temperature and ultimately impacting the energy-saving performance of the cooling water system.

[0004] Accordingly, there is a need in the art for a new control method for cooling water systems to solve the above problems. Summary of the Invention

[0005] The present invention aims to solve the above-mentioned technical problem, namely, to solve the problem that the approximation value of the existing cooling water system cannot simultaneously take into account both accuracy and stability.

[0006] This invention provides a control method for a cooling water system, the cooling water system comprising: a cooling tower; a first temperature sensor, the first temperature sensor being used to detect the outlet water temperature value of the cooling tower; the control method comprising: acquiring an outdoor wet-bulb temperature value; determining a preset temperature range into which the wet-bulb temperature value falls based on the wet-bulb temperature value; acquiring the outlet water temperature value; if the difference between the outlet water temperature values ​​acquired at intervals of a set time is less than a set temperature difference value, determining whether the wet-bulb temperature value still falls within the temperature range; if the wet-bulb temperature value still falls within the temperature range, determining an approximation value of the temperature range.

[0007] When the above technical solution is adopted, if the difference between the outlet water temperature values ​​obtained at the set interval is less than the set temperature difference value, it indicates that the cooling water system is operating relatively stably. If the wet-bulb temperature value during this period continues to fall within the preset temperature range, it indicates that the outdoor ambient temperature and humidity are also relatively stable. Under the above stable conditions, the approximation value can stably reflect the cooling capacity of the cooling water system. Since the approximation value only corresponds to the current temperature range, it can accurately reflect the cooling capacity of the cooling water system in the current temperature range. Therefore, the approximation value determined by the above method can simultaneously take into account both accuracy and stability.

[0008] In a specific implementation of the above-mentioned cooling water system control method, the step of "determining the approximation value of the temperature range" further includes: calculating the approximation value of the temperature range based on the wet-bulb temperature value and the outlet water temperature value.

[0009] When the above technical solution is adopted, the approximation value calculated based on the wet-bulb temperature value and outlet water temperature value obtained under steady state can stably and accurately reflect the cooling capacity of the chilled water system in the current temperature range.

[0010] In a specific implementation of the control method for the cooling water system described above, before the step of "obtaining the outlet water temperature value", the control method further includes: obtaining a set approximation value corresponding to the temperature range; determining whether the set approximation value is a preset initial approximation value; the step of "obtaining the outlet water temperature value" further includes: if the set approximation value is the initial approximation value, then obtaining the outlet water temperature value.

[0011] When using the above technical solution, if the set approximation value is the initial approximation value, it means that the set approximation value corresponding to the temperature range has not yet been calculated. At this time, the outlet water temperature value is obtained, and subsequent steps are performed to determine the approximation value corresponding to the temperature range.

[0012] In a specific implementation of the above-mentioned control method for the cooling water system, after the step of "determining the approximation value of the temperature range", the control method further includes: updating the set approximation value of the temperature range to the determined approximation value of the temperature range.

[0013] When the above technical solution is adopted, after determining the approximation value, the determined value is updated to the set approximation value of the corresponding temperature range, so that it can be directly called in subsequent use.

[0014] In a specific implementation of the control method for the cooling water system described above, the step of "obtaining the outdoor wet-bulb temperature value" further includes: after receiving an automatic calculation command, obtaining the wet-bulb temperature value.

[0015] When the above technical solution is adopted, after receiving the automatic calculation instruction, the operation of obtaining the wet-bulb temperature value is performed, and finally the approximation value is determined, providing a way to start automatic calculation.

[0016] In a specific embodiment of the control method for the above-mentioned cooling water system, the cooling water system further includes: a hardness sensor, which is used to detect the hardness of the water in the cooling tower; the control method further includes: acquiring the hardness value measured by the hardness sensor; determining a preset hardness range into which the hardness value falls based on the hardness value; acquiring a preset delay time value corresponding to the hardness range; if the hardness value continues to fall within the hardness range within the delay time value, resetting the preset approximation value to the initial approximation value; and issuing the automatic calculation command.

[0017] When the above technical solution is adopted, since the cooling capacity of the cooling water system is mainly affected by the hardness of the cooling water under other unchanged operating conditions, the hardness of the water in the cooling tower is detected by a hardness sensor. The delay time is determined according to the hardness range in which the hardness value falls. If the hardness value continues to fall within the hardness range within the delay time, it indicates that the hardness value has affected the cooling capacity of the cooling water system. Therefore, it is necessary to reset the set approximation value to the initial approximation value and issue a command to recalculate the approximation value.

[0018] In a specific embodiment of the control method for the above-mentioned cooling water system, the cooling water system further includes: a second temperature sensor for detecting the outdoor dry-bulb temperature; a first humidity sensor for detecting the outdoor relative humidity; before the step of "obtaining the outdoor wet-bulb temperature value", the control method further includes: obtaining the dry-bulb temperature value measured by the second temperature sensor; obtaining the relative humidity value measured by the first humidity sensor; the step of "obtaining the outdoor wet-bulb temperature value" further includes: calculating the wet-bulb temperature value based on the dry-bulb temperature value and the relative humidity value.

[0019] By adopting the above technical solution, the wet-bulb temperature value can be calculated from the real-time measured dry-bulb temperature value and relative humidity value, thus obtaining an accurate wet-bulb temperature value.

[0020] In a specific implementation of the above-mentioned cooling water system control method, after the step of "determining whether the wet-bulb temperature value still falls within the temperature range", the control method further includes: if the wet-bulb temperature value falls outside the temperature range, proceeding to the step of "determining the preset temperature range into which the wet-bulb temperature value falls".

[0021] If the wet-bulb temperature falls outside the initially determined temperature range when the above technical solution is adopted, it indicates that the wet-bulb temperature has changed significantly in a short period of time. At this time, the determined approximation value cannot stably reflect the cooling capacity of the initially determined temperature range. Therefore, it is necessary to go to the step of "determining the preset temperature range in which the wet-bulb temperature value falls" and start the judgment and calculation again from the beginning.

[0022] In a specific embodiment of the above-mentioned control method for the cooling water system, the cooling water system further includes a cooling tower fan; the control method further includes: determining whether the cooling water system is executing a start-up procedure; determining whether the cooling water system is executing a shutdown procedure; determining whether the cooling water system is executing a fan addition procedure; determining whether the cooling water system is executing a fan reduction procedure; determining whether the cooling water system is in a non-group control mode; determining whether the cooling tower fan is in a closed state; the step of "determining the approximation value of the temperature range" further includes: if the determination results are all negative, then determining the approximation value.

[0023] If all the above technical solutions are negative, it means that the cooling water system is not executing the start-up, shutdown, addition, or reduction procedures. The cooling water system is in group control mode and the cooling tower fan is running. At this time, the cooling water system is in normal operation, and the determined approximation value can normally reflect the cooling capacity of the cooling tower system.

[0024] In a specific embodiment of the above-mentioned control method for the cooling water system, the cooling water system further includes a cooling tower fan and a cooling pump; before the step of "obtaining the outlet water temperature value", the control method further includes: controlling the cooling tower fan to operate at a first set frequency value; and controlling the cooling pump to operate at a second set frequency value.

[0025] By adopting the above technical solution, the cooling tower fan and cooling pump are controlled to operate at fixed values ​​to avoid the influence of changes in the cooling tower fan and cooling pump on the calculation results during the approximation value calculation process, thus ensuring that a stable approximation value that accurately reflects the cooling capacity can be obtained.

[0026] Compared with the prior art, the beneficial effect of the cooling water system control method provided by the present invention is that when the difference between the outlet water temperature values ​​obtained at intervals of a set time value is less than the set temperature difference value, it indicates that the operation of the cooling water system is relatively stable. If the wet-bulb temperature value during this period continues to fall within the preset temperature range, it indicates that the outdoor ambient temperature and humidity are also relatively stable. Under the above stable state, the approximation value can stably reflect the cooling capacity of the cooling water system. Since the approximation value only corresponds to the current temperature range, it can accurately reflect the cooling capacity of the cooling water system in the current temperature range. Therefore, the approximation value determined by the above method can simultaneously take into account both accuracy and stability. Attached Figure Description

[0027] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0028] Figure 1 This is a flowchart of the main steps of the control method for the cooling water system of the present invention;

[0029] Figure 2 This is a detailed flowchart of one embodiment of the cooling water system control method of the present invention. Detailed Implementation

[0030] Some embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0031] It should be noted that, in the description of this invention, "processor" can include hardware, software, or a combination of both. A processor can be a central processing unit, a microprocessor, a digital signal processor, or any other suitable processor. The processor has data and / or signal processing capabilities. The processor can be implemented in software, in hardware, or a combination of both. The term "A and / or B" indicates all possible combinations of A and B, such as only A, only B, or A and B. Ordinal numbers such as "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] Furthermore, it should be noted that although the various steps of the control method of the present invention are described in a specific order in the description of the present invention, these orders are not restrictive. Without departing from the basic principles of the present invention, those skilled in the art can perform the steps in different orders.

[0033] As pointed out in the background art, the approximation value of the existing cooling water system cannot simultaneously take into account both accuracy and stability. The present invention provides a control method for a cooling water system. When the difference between the outlet water temperature values ​​obtained at intervals of a set time is less than the set temperature difference value, it indicates that the operation of the cooling water system is relatively stable. If the wet-bulb temperature value during this period continuously falls within the preset temperature range, it indicates that the outdoor ambient temperature and humidity are also relatively stable. Therefore, under the above stable state, determining the approximation value can stably reflect the cooling capacity of the cooling water system. Since the approximation value only corresponds to the current temperature range, it can accurately reflect the cooling capacity of the cooling water system in the current temperature range. Therefore, the approximation value determined by the above method can simultaneously take into account both accuracy and stability.

[0034] The cooling water system of the present invention includes a cooling tower, a cooling tower fan, and a cooling pump. The number of cooling towers can be one or more. The cooling tower fan is located at the top of the cooling tower, or it can be located on the side or bottom of the cooling tower. The cooling tower fan can force airflow, so that the air exchanges heat with the water in the cooling tower and carries away the heat. The cooling pump is located on the pipeline of the cooling water system and is used to pump the cooling water carrying waste heat in the pipeline into the cooling tower and provide power for the circulation of cooling water in the cooling water system. The cooling water system also includes a first temperature sensor, a second temperature sensor, a first humidity sensor, and a hardness sensor. The first temperature sensor detects the outlet water temperature of the cooling tower and can be located at the outlet of the cooling tower or inside the outlet pipe. The second temperature sensor detects the outdoor dry-bulb temperature, and the first humidity sensor detects the outdoor relative humidity. Both the second temperature sensor and the first humidity sensor can be located on the outdoor unit. If the cooling tower is located outdoors, they can also be located at the air inlet of the cooling tower or on the outside of the casing. The hardness sensor is located inside the cooling water of the cooling tower and is used to detect the hardness of the water. The hardness sensor is a water hardness sensor, which can be an electrochemical sensor that uses an ion-selective electrode to measure the ion concentration in the water to detect the hardness, or an optical sensor that uses a light-emitting diode and a photosensitive diode to detect the color change of water after reacting with chemical agents to detect the hardness. It should be noted that the second temperature sensor and the first humidity sensor can be integrated temperature and humidity sensors.

[0035] The cooling water system also includes a processor and a memory. The memory is suitable for storing multiple lines of program code, which are then loaded and executed by the processor to perform the cooling water system's detection methods. The processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The memory can be an internal storage unit of the cooling water system, such as a hard drive or RAM; it can also be an external storage device, such as a plug-in hard drive, smart memory card, secure digital card, flash memory card, etc., installed on the cooling water system; or it can include both internal and external storage units. The cooling water system can include multiple memories and multiple processors, each executing different steps. These processors can be deployed on the same device or on different devices; for example, multiple processors could be processors on the cooling water system and processors on a cloud server.

[0036] First refer to Figure 1 The figure illustrates the main steps of the cooling water system control method of the present invention, specifically including the following steps:

[0037] Step S100: Obtain the outdoor wet-bulb temperature value.

[0038] Step S101: Determine the preset temperature range into which the wet-bulb temperature value falls based on the wet-bulb temperature value.

[0039] Step S102: Obtain the outlet water temperature value.

[0040] Step S103: If the difference between the outlet water temperature values ​​obtained at the set interval is less than the set temperature difference value, determine whether the wet-bulb temperature value still falls within the temperature range.

[0041] Step S104: If the wet-bulb temperature value still falls within the temperature range, determine the approximation value of the temperature range.

[0042] When the difference between the outlet water temperature values ​​obtained at the set interval is less than the set temperature difference, it indicates that the cooling water system is operating relatively stably. If the wet-bulb temperature value during this period continues to fall within the preset temperature range, it indicates that the outdoor ambient temperature and humidity are also relatively stable. Under the above stable conditions, the approximation value can stably reflect the cooling capacity of the cooling water system. Since the approximation value only corresponds to the current temperature range, it can accurately reflect the cooling capacity of the cooling water system in the current temperature range. Therefore, the approximation value determined by the above method can simultaneously take into account both accuracy and stability.

[0043] Once the approximation value is determined, the target outlet water temperature can be calculated using the approximation value and the wet-bulb temperature value. Then, the frequency of the cooling tower fan and cooling pump can be adjusted and controlled based on the target outlet water temperature to achieve better energy-saving effects. The specific calculation formula is: Target outlet water temperature = Wet-bulb temperature + Approximation value + Adjustment motor setpoint. The adjustment motor setpoint can be selected as 2℃, or it can be adjusted according to specific usage conditions and test results.

[0044] Specifically, the wet-bulb temperature value can be obtained by calculating the dry-bulb temperature measured by the second temperature sensor and the relative humidity measured by the first humidity sensor. This method has the advantages of simple measurement and low cost. For example, the formula for calculating the wet-bulb temperature value can be Twb=Tdb-((-0.36+0.133×sqrt(100-RH))×(Tdb-14.55) / (-0.36+0.133×sqrt(RH)), where Twb is the wet-bulb temperature value in °C, Tdb is the dry-bulb temperature value in °C, RH is the relative humidity, and sqrt represents the square root. Other formulas can also be used to calculate the wet-bulb temperature value. In addition, the wet-bulb temperature value can also be detected by setting a wet-bulb thermometer, which has the advantages of high automation and accurate results.

[0045] It should be noted that the cooling water system can be preset with one or more temperature ranges as needed. "Determining the preset temperature range into which the wet-bulb temperature value falls" means determining which preset temperature range the wet-bulb temperature value falls within. Optionally, seven temperature ranges can be set, with corresponding temperature ranges of 17℃~20℃, 20℃~23℃, 23℃~26℃, 26℃~29℃, 29℃~32℃, 32℃~35℃, and 35℃~38℃.

[0046] The "set duration value" in step S103 can be set to different values ​​according to changes in outdoor temperature and humidity, or it can be a relatively fixed value, as long as the difference in outlet water temperature values ​​obtained at intervals of the set duration value can reflect the operating status of the cooling water system. For example, the set duration value can be set in the range of 5 to 15 minutes, preferably 10 minutes. This invention does not specifically limit the specific value of the set duration value. The "set temperature difference value" can be set to different values ​​according to usage requirements, as long as the difference in outlet water temperature values ​​obtained at intervals of the set duration value is less than the set temperature difference value, the system's operating status is relatively stable. For example, the set temperature difference value can be set in the range of 1 to 5℃, preferably 5℃. This invention does not specifically limit the specific value of the set temperature difference value.

[0047] In the process from "determining the preset temperature range into which the wet-bulb temperature value falls" in step S101 to "when the difference between the outlet water temperature values ​​obtained at intervals of a set time value is less than the set temperature difference value" in step S103, the wet-bulb temperature value is preferably kept within the initially determined temperature range to ensure that the wet-bulb temperature value changes little in a short period of time, thereby ensuring that the outdoor ambient temperature and humidity remain relatively stable.

[0048] In step S104, "determine the approximation value of the temperature range" can be calculated based on the real-time wet-bulb temperature value and the outlet water temperature value. The specific calculation formula can be approximation value = outlet water temperature value - wet-bulb temperature value, or other calculation formulas. "Determine the approximation value of the temperature range" can also be determined by the user based on the current situation and input.

[0049] See last for reference. Figure 2 The figure illustrates the detailed steps of one embodiment of the cooling water system control method of the present invention, specifically including the following steps:

[0050] Step S200: After receiving the automatic calculation command, obtain the dry bulb temperature value.

[0051] Step S201: Obtain the relative humidity value;

[0052] Step S202: Calculate the wet-bulb temperature based on the dry-bulb temperature and relative humidity.

[0053] Step S203: Determine the preset temperature range into which the wet-bulb temperature value falls based on the wet-bulb temperature value.

[0054] Step S204: Obtain the set approximation value corresponding to the temperature range.

[0055] Step S205: Determine whether the set approximation value is the preset initial approximation value. If the determination result is yes, proceed to step S206; if the determination result is no, proceed to step S213.

[0056] Step S206: Control the cooling tower fan to operate at the first set frequency value.

[0057] Step S207: Control the cooling pump to operate at the second set frequency value.

[0058] Step S208: Obtain the outlet water temperature value.

[0059] Step S209: Determine whether the difference between the outlet water temperature values ​​obtained from the set interval time value is less than the set temperature difference value. If the determination result is yes, proceed to step S210; if the determination result is no, proceed to step S208.

[0060] Step S210: Determine whether the wet-bulb temperature value still falls within the temperature range. If the determination result is yes, proceed to step S211; if the determination result is no, proceed to step S203.

[0061] Step S211: Calculate the approximation value of the temperature range based on the wet-bulb temperature value and the outlet water temperature value.

[0062] Step S212: Update the set approximation value of the temperature range to the approximation value of the determined temperature range.

[0063] Step S213: Do not calculate the approximation value for the temperature range.

[0064] Specifically, in step S200, the "automatic calculation command" can be issued under the following circumstances: acquiring the hardness value measured by the hardness sensor; determining the preset hardness range into which the hardness value falls based on the hardness value; acquiring the preset delay time value corresponding to the hardness range; if the hardness value continues to fall within the hardness range within the delay time value, resetting the set approximation value to the initial approximation value; and issuing the automatic calculation command. Alternatively, the "automatic calculation command" can be determined by the user, who can then manually reset the set approximation value to the initial approximation value, and then click the automatic calculation button or select the automatic calculation option.

[0065] Before determining the approximation value of the temperature range, the following conditions need to be assessed: whether the cooling water system is executing a start-up procedure; whether the cooling water system is executing a shutdown procedure; whether the cooling water system is executing a power-on procedure; whether the cooling water system is executing a power-off procedure; whether the cooling water system is in a non-group control mode; and whether the cooling tower fan is in a closed state. The startup procedure refers to a preset program executed in response to a startup command. This startup procedure can be customized and set according to actual conditions and system requirements. For example, it may include at least one of the following: controlling the cooling pump to start and ramping up to a first frequency at a preset first ramp rate, or controlling the valve opening to open to a first degree at a preset first rate. The shutdown procedure refers to a preset program executed in response to a shutdown command. This shutdown procedure can be customized and set according to actual conditions and system requirements. For example, it may include at least one of the following: controlling the cooling pump to shut down, controlling the valve opening to decrease to close at a preset second rate, or controlling the cooling tower fan to shut down. The additional cooling capacity procedure refers to a preset program executed in response to an additional cooling capacity command. This additional cooling capacity procedure is typically executed when additional cooling capacity is needed to meet chilled water supply requirements. The requirements can be customized and set. For example, the addition program may include controlling the valve opening to decrease to a third opening at a preset third rate, controlling the cooling pump to increase its frequency to a third frequency at a third increase rate, and controlling the cooling tower fan to increase its frequency to a fourth frequency at a fourth increase frequency. The reduction program refers to a preset program executed in response to a reduction command. The reduction program is usually executed when the cooling capacity needs to be reduced to meet the chilled water supply demand. The reduction program can be customized and set according to the actual situation and system requirements. For example, the reduction program may include controlling the valve opening to increase to a fourth opening at a preset fourth rate, controlling the cooling pump to decrease its frequency to a fifth frequency at a third decrease rate, and controlling the cooling tower fan to decrease its frequency to a sixth frequency at a fourth decrease frequency. The group control mode refers to the cooling water system being able to uniformly control the valves, cooling tower fans, cooling pumps, and other equipment of the cooling water system through a controller. If all of the above judgment results are negative, the approximation value is determined; if any of the above judgment results are positive, step S213 is executed. If all the above judgment results are negative, it indicates that the cooling water system is in normal operation and the determined approximation value can normally reflect the cooling capacity of the cooling tower system.

[0066] After step S213 "Do not calculate the approximation value of the temperature range", other calculation procedures can be performed, or the user can be waited to manually input the approximation value.

[0067] Regarding the "set approximation value," it refers to a preset approximation value for each of one or more temperature ranges. After the cooling water system is used for the first time or after the set approximation value is reset, the specific value of the set approximation value becomes the initial approximation value. Each time the approximation value for a temperature range is determined, the specific value of the set approximation value is updated to the determined approximation value. The "initial approximation value" can be 0℃ or other initial values ​​as needed; this invention does not specifically limit this. For example, if the initial approximation value is 0℃ and the set approximation value for the 17℃~20℃ temperature range is 30℃, then the set approximation value is not the initial approximation value, and the approximation value for that temperature range is not calculated. If the initial approximation value is 0℃ and the set approximation value for the 17℃~20℃ temperature range is 0℃, then the set approximation value is the initial approximation value, and the approximation value for the temperature range is calculated. If the calculated approximation value is 28℃, then the set approximation value is updated to 28℃.

[0068] It should be noted that the first set frequency value and the second set frequency value can be the same or different. They can be set to different values ​​according to the usage requirements, as long as the cooling tower fan and cooling pump can operate at fixed values. For example, the first set frequency value and the second set frequency value can be set in the range of 40 to 60 Hz, preferably both of the first set frequency value and the second set frequency value are 50 Hz. The present invention does not specifically limit the specific values ​​of the first set frequency value and the second set frequency value.

[0069] Furthermore, the order of "obtaining the dry-bulb temperature value" in step S200 and "obtaining the relative humidity value" in step S201 is not restrictive and can be adjusted as needed; the order of steps S206 and S207 is also not restrictive and can be adjusted as needed.

[0070] Those skilled in the art will understand that after the step of "determining the preset temperature range into which the wet-bulb temperature value falls based on the wet-bulb temperature value," the control method may further include: determining whether the wet-bulb temperature value is equal to the midpoint of the temperature range; the step of "obtaining the set approximation value corresponding to the temperature range" further includes: if the wet-bulb temperature value is equal to the midpoint of the temperature range, then obtaining the set approximation value corresponding to the temperature range. Here, the midpoint of the temperature range is half the sum of the lower and upper limits of the temperature range; for example, in a temperature range of 17℃ to 20℃, the midpoint is 18.5℃. When the wet-bulb temperature value is equal to the midpoint of the temperature range, even if the wet-bulb temperature value changes slightly, it is unlikely to fall outside the temperature range.

[0071] Furthermore, in step S210, "determining whether the wet-bulb temperature value still falls within the temperature range" can be done by directly judging the wet-bulb temperature value, or by rounding the wet-bulb temperature value before judging, to meet the programming requirements of the program. Those skilled in the art can make adjustments as needed.

[0072] It should be noted that the above embodiments are merely used to illustrate the principles of the present invention and are not intended to limit the scope of protection of the present invention. Without departing from the principles of the present invention, those skilled in the art can adjust the above embodiments so that the present invention can be applied to more specific application scenarios.

[0073] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A control method for a cooling water system, characterized in that, The cooling water system includes: Cooling tower; A first temperature sensor is used to detect the outlet water temperature of the cooling tower. The control method includes: Obtain the outdoor wet-bulb temperature value; Based on the wet-bulb temperature value, a preset temperature range in which the wet-bulb temperature value falls is determined; Obtain the outlet water temperature value; If the difference between the outlet water temperature values ​​obtained at a set interval is less than a set temperature difference value, determine whether the wet-bulb temperature value still falls within the temperature range. If the wet-bulb temperature value still falls within the temperature range, determine the approximation value of the temperature range.

2. The control method for the cooling water system according to claim 1, characterized in that, The step of "determining the approximation value of the temperature range" further includes: The approximation value of the temperature range is calculated based on the wet-bulb temperature value and the outlet water temperature value.

3. The control method for the cooling water system according to claim 1, characterized in that, Before the step of "obtaining the outlet water temperature value", the control method further includes: Obtain the set approximation value corresponding to the temperature range; Determine whether the set approximation value is the preset initial approximation value; The step of "obtaining the outlet water temperature value" further includes: If the set approximation value is the initial approximation value, then the outlet water temperature value is obtained.

4. The control method for the cooling water system according to claim 3, characterized in that, After the step of "determining the approximation value of the temperature range", the control method further includes: The set approximation value of the temperature range is updated to the determined approximation value of the temperature range.

5. The control method for the cooling water system according to claim 3, characterized in that, The step of "obtaining the outdoor wet-bulb temperature value" further includes: Upon receiving the automatic calculation command, the wet-bulb temperature value is obtained.

6. The control method for a cooling water system according to claim 5, characterized in that, The cooling water system also includes: A hardness sensor, used to detect the hardness of the water in the cooling tower; The control method further includes: Obtain the hardness value measured by the hardness sensor; Based on the hardness value, determine the preset hardness range into which the hardness value falls; Obtain the preset delay duration value corresponding to the hardness range; If the hardness value continues to fall within the hardness range within the specified delay time, the set approximation value is reset to the initial approximation value. Issue the automatic calculation command.

7. The control method for a cooling water system according to claim 1, characterized in that, The cooling water system also includes: The second temperature sensor is used to detect the outdoor dry-bulb temperature. A first humidity sensor is used to detect the outdoor relative humidity. Before the step of "obtaining the outdoor wet-bulb temperature value", the control method further includes: Obtain the dry bulb temperature value measured by the second temperature sensor; Obtain the relative humidity value measured by the first humidity sensor; The step of "obtaining the outdoor wet-bulb temperature value" further includes: The wet-bulb temperature is calculated based on the dry-bulb temperature and the relative humidity.

8. The control method for a cooling water system according to claim 1, characterized in that, After the step of "determining whether the wet-bulb temperature value still falls within the temperature range", the control method further includes: If the wet-bulb temperature value falls outside the temperature range, proceed to the step of "determining the preset temperature range in which the wet-bulb temperature value falls".

9. The control method for a cooling water system according to claim 1, characterized in that, The cooling water system also includes a cooling tower fan; The control method further includes: Determine whether the cooling water system is executing the startup procedure; Determine whether the cooling water system is currently executing a shutdown procedure; Determine whether the cooling water system is currently executing the machining procedure; Determine whether the cooling water system is currently executing a speed reduction procedure; Determine whether the cooling water system is in a non-group control mode; Determine whether the cooling tower fan is in the off state; The step of "determining the approximation value of the temperature range" further includes: If all the judgment results are negative, then the approximation value is determined.

10. The control method for a cooling water system according to claim 1, characterized in that, The cooling water system also includes a cooling tower fan and a cooling pump; Before the step of "obtaining the outlet water temperature value", the control method further includes: Control the cooling tower fan to operate at a first set frequency value; The cooling pump is controlled to operate at a second set frequency value.

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