Freeze prevention control system and method for indirect air-cooled towers

Abstract

We provide a freeze prevention control system for indirect air-cooled towers. [Solution] The control system includes a shutter curtain, a temperature sensor, and control components. The shutter curtain is installed at the air intake of the air-cooling tower, the temperature sensor is installed on the fin tube of the triangular heat sink, and the control components include a signal acquisition box, a PLC module, and a DCS module connected to each other. The signal acquisition box is used to collect temperature signals and actual shutter curtain opening signals. The PLC module is used to process the signals and generate a shutter curtain opening signal to be adjusted. The DCS module receives the shutter curtain opening signal to be adjusted and controls the opening of the shutter curtain by an actuator. The height of the shutter curtain is adjusted in real time according to the water outlet temperature of the fin tube, maintaining low back pressure operation of the unit while preventing freezing.

Description

[Technical Field]

[0001] The present invention relates to the technical field of power and energy engineering, and more particularly to a freeze prevention control system and method for indirect air-cooled towers. [Background technology]

[0002] As energy demand continues to rise, power plants in coal-rich but water-scarce regions play a vital role in electricity supply. Indirect air-cooled towers have played a crucial role in reducing water consumption as an important energy-saving technology in power plants. However, in some regions, low winter temperatures make the fin tube bundles of indirect air-cooled towers prone to freezing, affecting the normal operation and safe production of power plants.

[0003] Currently, the industry commonly uses adjusting the louver opening to address the challenge of preventing freezing in indirect air-cooled towers. However, louvers have problems such as air leaks and poor sealing, resulting in reduced freezing effectiveness and failing to meet actual needs.

[0004] Furthermore, existing indirect air-cooled tower defrosting systems typically adjust the opening of the defrosting device by monitoring the outflow temperature of the sector. Maintaining a high outflow temperature is necessary to ensure effective defrosting, which results in increased back pressure in the unit, leading to increased coal consumption and operating costs for the unit for power generation. [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention aims to solve, at least to some extent, one of the technical problems in related technologies.

[0006] Therefore, the embodiments of the present invention propose an antifreeze control system for an indirect air-cooled tower in order to solve the problems of the conventional technology, which have poor antifreeze effect and high operating costs. [Means for solving the problem]

[0007] The freeze prevention control system for an indirect air-cooled tower according to an embodiment of the present invention is: A shutter curtain is installed at the intake port of the triangular radiator of the air-cooling tower to adjust the amount of air intake to the triangular radiator, A temperature sensor is installed on the fin tube of the triangular heat sink of the air-cooling tower to monitor the water outlet temperature of the fin tube, A control component comprising a signal acquisition box, a PLC module, and a DCS module, wherein the signal acquisition box is connected to the shutter curtain and the temperature sensor and used to acquire a temperature signal and an actual opening signal of the shutter curtain; the PLC module is connected to the signal acquisition box and used to process the signals and generate a shutter curtain opening signal to be adjusted; and the DCS module is connected to the PLC module and used to receive the shutter curtain opening signal to be adjusted and to control the opening of the shutter curtain by an actuator.

[0008] In the freeze prevention control system for an indirect air-cooled tower according to an embodiment of the present invention, the height of the shutter curtain is precisely adjusted in real time according to the water outlet temperature of the fin tubes, thereby preventing freezing, maintaining low back pressure operation of the unit, improving power generation efficiency, and contributing to energy saving and environmental protection at the power plant.

[0009] In some embodiments, the area of ​​the shutter curtain matches the area of ​​the air intake of the triangular radiator, and the shutter curtain can adjust the air intake of the triangular radiator from fully open to fully closed.

[0010] In some embodiments, there are multiple shutter curtains, and each of the multiple shutter curtains corresponds one-to-one with each of the triangular radiators of the air-cooled tower.

[0011] In some embodiments, the temperature sensor is disposed on the wall of the water outlet tube of the outermost fin tube of the triangular radiator of the air-cooled tower.

[0012] In some embodiments, there are a plurality of the temperature sensors, and the plurality of temperature sensors are arranged at intervals in the length direction of the fin tube.

[0013] The embodiment of the present invention further proposes a freezing prevention control method for an indirect air-cooled tower, and the freezing prevention control method is used in the freezing prevention control system of the indirect air-cooled tower described in any of the above embodiments.

[0014] The freezing prevention control method for an indirect air-cooled tower according to the embodiment of the present invention includes: monitoring in real time, by a temperature sensor, the water outlet temperature of the outermost fin tube of each triangular radiator; transmitting a temperature signal and an actual opening degree signal of a shutter curtain to a PLC module; processing, by the PLC module, the signals to generate a shutter curtain opening degree signal of an adjustment target; transmitting the shutter curtain opening degree signal of the adjustment target to a DCS module; controlling, by the DCS module, the opening degree of the shutter curtain via an actuator.

[0015] In some embodiments, when processing the temperature signal, the PLC module calibrates the temperature sensor using a temperature-known standard source, records the output signal of the sensor at the standard temperature, sets or inputs the temperature value corresponding to the standard signal into the program of the PLC module, and the calibration formula to be satisfied is as follows: TIFF2026093330000002.tif6170Here, T is the temperature, V is the voltage output of the temperature sensor, and a and b are calibration coefficients.

[0016] In some embodiments, the environmental temperature T env , humidity Henv Monitor and collect the meteorological data as a reference for freeze prevention control, The heat dissipation efficiency of the fin tube has a linear relationship with the ambient temperature. The influence of the ambient temperature on the outlet water temperature T of the fin tube out satisfies the following relational expression, TIFF2026093330000003.tif7170 where T in is the temperature of the cooling water entering the fin tube, k1 is the heat dissipation efficiency coefficient, and T base is the reference ambient temperature, When introducing the humidity coefficient k2, the influence of humidity on the outlet water temperature of the fin tube satisfies the following relational expression, TIFF2026093330000004.tif7170 where H env is the ambient humidity, and H base is the reference humidity, The freeze prevention control strategy determines the opening degree O of the shutter curtain based on the combination of ambient temperature and humidity, sets the critical conditions, and adjusts the opening degree of the shutter curtain when the combination of ambient temperature and humidity exceeds this condition, TIFF2026093330000005.tif17170 where O max is the maximum opening degree of the shutter curtain, O[[ID=*]] min is the minimum opening degree, T th and H th are the thresholds of ambient temperature and humidity respectively, and k3 and k4 are adjustment coefficients.

[0017] In some embodiments, the actual opening degree of the shutter curtain and the outlet water temperature of the triangular radiator satisfy the following relational expression, TIFF2026093330000006.tif13170 where k is the sensitivity coefficient of the outlet water temperature to the opening degree change of the shutter curtain, representing the responsiveness of the temperature change to the opening degree change, and b is a constant term for adjusting the temperature change rate when the opening degree is close to O min is a constant term for adjusting the temperature change rate when the opening degree is close to O

[0018] <* In some embodiments, the sensitivity coefficient of the outflow water temperature to changes in the opening of the shutter curtain is determined through experimental methods. A series of opening points for the shutter curtain are selected, and while keeping all variables constant, the opening of the shutter curtain is changed. For each predetermined opening of the shutter curtain, the outflow water temperature of the fin tube bundle of the triangular radiator is monitored in real time. The relationship between the opening and the outflow water temperature is fitted using linear regression analysis, and the slope is taken as the sensitivity coefficient. [Brief explanation of the drawing]

[0019] [Figure 1] This is a schematic diagram of a freeze prevention control system for an indirect air-cooled tower in an embodiment of the present invention. [Modes for carrying out the invention]

[0020] The embodiments of the present invention will now be described in detail. Examples of the embodiments are shown in the drawings. The embodiments described below with reference to the drawings are illustrative for illustrating the present invention and should not be understood as limiting the present invention.

[0021] The following describes an embodiment of the freeze prevention control system for an indirect air-cooled tower according to the present invention, with reference to the drawings.

[0022] As shown in Figure 1, the freeze prevention control system for an indirect air-cooled tower according to an embodiment of the present invention includes a shutter curtain 3, a temperature sensor 2, and a control component.

[0023] Here, the indirect air-cooled tower 1 mainly consists of an upper tower tube and a bundle of fin tubes of a triangular radiator at the bottom. A shutter curtain 3 is installed at the intake of the triangular radiator and is used to adjust the amount of air intake to the triangular radiator. A temperature sensor 2 is installed on the fin tube of the triangular radiator and is used to monitor the water outlet temperature of the fin tube.

[0024] The control components include a signal acquisition box, a PLC module 4, and a DCS module 5. The signal acquisition box is connected to the shutter curtain 3 and the temperature sensor 2, and is used to acquire the temperature signal and the actual opening signal of the shutter curtain 3. The PLC module 4 is connected to the signal acquisition box and is used to process the signals and generate the shutter curtain opening signal to be adjusted (i.e., the new opening signal of the shutter curtain). The DCS module 5 is connected to the PLC module 4 and is used to receive the shutter curtain opening signal to be adjusted and to control the opening of the shutter curtain 3 by the actuator 8, thereby achieving the purpose of preventing freezing.

[0025] Optionally, the signal acquisition box includes a first acquisition box 6 and a second acquisition box 7, the first acquisition box 6 being used to acquire the actual opening signal of the shutter curtain 3, and the second acquisition box 7 being used to acquire the temperature signal.

[0026] In essence, temperature sensor 2 is used to monitor the water outlet temperature of the outermost fin tube of each triangular heat sink in real time and to transmit the monitored temperature signal to the signal acquisition box. The opening signal of shutter curtain 3 is also collected and transmitted to the signal acquisition box.

[0027] The signal acquisition box transmits the collected temperature signal and shutter curtain opening signal to the PLC module 4. The PLC module 4 processes these signals and, according to a pre-configured algorithm and logic, calculates the required opening of the shutter curtain 3 in response to the current temperature conditions.

[0028] Based on the processed data, the PLC module 4 generates new opening commands for the shutter curtain 3. These commands adjust the opening of the shutter curtain 3 to prevent the fin tube bundle from freezing while maintaining low back pressure operation of the unit.

[0029] A new opening command for the shutter curtain 3 is transmitted to the actuator 8 by the DCS module 5. The actuator 8 adjusts the opening degree of the shutter curtain 3 by controlling the motor of the shutter curtain 3 according to the received command.

[0030] The system further includes a feedback mechanism to monitor the actual opening of the shutter curtain 3 and compare it with a target opening set in the PLC module 4. If a difference exists, the system makes corresponding adjustments so that the opening of the shutter curtain 3 matches the target opening.

[0031] In the freeze prevention control system for an indirect air-cooled tower according to an embodiment of the present invention, the height of the shutter curtain 3 is precisely adjusted in real time according to the water outlet temperature of the fin tubes, thereby preventing freezing, maintaining low back pressure operation of the unit, improving power generation efficiency, and contributing to energy saving and environmental protection at the power plant.

[0032] In some embodiments, the area of ​​the shutter curtain 3 matches the area of ​​the intake port of the triangular radiator, and the shutter curtain 3 can adjust the intake port of the triangular radiator from fully open to fully closed. In other words, the shutter curtain 3 can completely cover the intake port of the triangular radiator and can be adjusted to any opening from fully open to fully closed. If there is no risk of freezing, the shutter curtain 3 can be fully retracted upward without affecting the intake of the air-cooling tower 1.

[0033] Furthermore, there are multiple shutter curtains 3, and each of the multiple shutter curtains 3 corresponds one-to-one with each of the triangular heat sinks of the air-cooling tower 1. The opening degree of the shutter curtains 3 can be controlled as a whole, in groups, or individually, providing a flexible adjustment method.

[0034] In some embodiments, the temperature sensor 2 is positioned on the wall of the water outlet tube of the outermost fin tube of the triangular heat sink of the air-cooling tower 1. Because the position is where the water temperature is lowest, the water outlet temperature of the fin tube can be accurately monitored.

[0035] Furthermore, there are multiple temperature sensors 2, which are spaced apart along the length of the fin tubes. In other words, several temperature sensors 2 are placed on the walls of the water outlet tubes of the outermost fin tubes of each triangular heat sink, and the lowest temperature is used as the input value for the control component.

[0036] The following describes a freeze prevention control method for an indirect air-cooled tower according to an embodiment of the present invention. This freeze prevention control method is used in the freeze prevention control system for an indirect air-cooled tower in any of the embodiments described above.

[0037] A method for controlling the freeze prevention of an indirect air-cooled tower according to an embodiment of the present invention includes the following steps 1 to 6.

[0038] Step 1: Monitor the water outlet temperature of the outermost fin tube of each triangular radiator in real time using temperature sensor 2. This ensures that the monitoring point is at the lowest water temperature, allowing for an accurate assessment of the freezing risk. Install an air velocity sensor to monitor the air velocity at the intake of the triangular radiator, helping to determine the impact of environmental conditions on the cooling effect. Collect meteorological data such as ambient temperature and humidity as reference criteria for freeze prevention control.

[0039] Step 2: The temperature sensor 2, wind speed sensor, and shutter curtain opening signals are transmitted to the PLC module 4, which then performs preprocessing on the received signals, including filtering and noise reduction, unit conversion, and signal calibration.

[0040] Step 3: The PLC module 4 processes the signals using a pre-configured algorithm (e.g., fuzzy control, PID control) based on temperature, wind speed, and environmental data. Based on the processed data, trend analysis and predictions are performed in combination with historical operating data and historical freezing events. The PLC module 4 generates a new shutter curtain opening signal, which takes into account the current temperature conditions, environmental factors, and predicted freezing risk.

[0041] Step 4: A new opening signal for the shutter curtain is transmitted to the DCS module 5, which verifies the received signal, generates a control command, and prepares the actuator 8 for operation.

[0042] Step 5: The DCS module 5 controls the opening degree of the shutter curtain 3 via the actuator 8 (e.g., motor controller). After adjusting the opening degree, the sensor provides feedback on the actual opening degree of the shutter curtain 3 and the change in the water outlet temperature of the triangular heat sink. Based on the feedback information, the PLC module 4 performs closed-loop control and fine-tunes the opening degree of the shutter curtain 3 to ensure optimal freeze prevention.

[0043] Step 6: Continuously monitor the water outlet temperature of the triangular radiator, the opening degree of the shutter curtain 3, and environmental conditions to ensure the system is operating in optimal conditions. Regularly analyze the operating data to optimize the antifreeze control strategy and improve the system's adaptability and antifreeze efficiency. If any system abnormality or failure is detected, automatically switch to safety mode and issue an alarm for timely action.

[0044] As a result, the indirect air-cooled tower 1's antifreeze system, with its detailed and expanded control method, can respond accurately and intelligently to various operating conditions and environmental changes, thereby improving the antifreeze effect and system reliability.

[0045] In some embodiments, calibration is performed when the PLC module 4 processes the temperature signal to ensure that the measurements from the sensor and the PLC module 4 match the actual temperature value, thereby ensuring reading accuracy.

[0046] Using a standard source with a known temperature (e.g., a constant temperature bath), the temperature sensor 2 is calibrated, the sensor's output signal (e.g., voltage or current) at the standard temperature is recorded, and the temperature value corresponding to the standard signal is set or input into the program of the PLC module 4.

[0047] For example, when using a thermocouple sensor, the calibration formula to be input is as follows: TIFF2026093330000007.tif6170 Here, T is the temperature, V is the voltage output of temperature sensor 2, and a and b are the calibration coefficients.

[0048] In some embodiments, an environmental detection sensor detects the ambient temperature T env , humidity H env Weather data is monitored and collected as a reference standard for anti-freezing control. This data is directly related to the heat dissipation efficiency and freezing risk of the air-cooled tower 1.

[0049] The heat dissipation efficiency of the fin tube is linearly related to the ambient temperature, and the outlet water temperature T of the fin tube out The effect of ambient temperature on this satisfies the following relationship. TIFF2026093330000008.tif7170 Here, T in is the temperature of the cooling water entering the fin tube, k1 is the heat dissipation efficiency coefficient, and T base This is the reference ambient temperature.

[0050] Furthermore, since high humidity reduces heat dissipation capacity, humidity may affect the heat dissipation efficiency of air-cooled tower 1.

[0051] Therefore, when a humidity coefficient k2 is introduced, the effect of humidity on the water outlet temperature of the fin tube satisfies the following relationship: TIFF2026093330000009.tif7170 Here, H env This is the ambient humidity, H base This is the standard humidity.

[0052] The anti-freezing control strategy determines the opening degree O of the shutter curtain 3 based on the combination of ambient temperature and humidity, sets critical conditions, and prevents freezing by adjusting the opening degree of the shutter curtain 3 when the combination of ambient temperature and humidity exceeds these conditions. TIFF2026093330000010.tif17170 Here, O max This is the maximum opening of the shutter curtain 3, and O min This is the minimum opening, and T th and H th k3 and k4 are the ambient temperature and humidity thresholds, respectively, and k3 and k4 are the adjustment coefficients.

[0053] The coefficients (k1, k2, k3, k4) in these equations should be determined based on actual operating data and historical freezing events to optimize the anti-freezing control strategy. Using such a mathematical model allows for a more scientific formulation of anti-freezing measures, ensuring the safe and efficient operation of air-cooled tower 1 even under harsh environmental conditions.

[0054] In some embodiments, the relationship between the actual opening of the shutter curtain 3 and the outlet water temperature of the triangular radiator can be expressed by the following equation. For example, if this relationship is linear, that is, if the outlet water temperature decreases as the opening increases, it can be expressed as follows. TIFF2026093330000011.tif7170 Here, T out This is the outlet water temperature of the triangular radiator, and T base is the water outlet temperature when there is no risk of freezing, i.e., the water outlet temperature when the shutter curtain 3 is fully open, k is the sensitivity coefficient of the water outlet temperature to the change in the opening of the shutter curtain 3, representing the degree of response of the temperature change to the change in opening, and O is the actual opening of the shutter curtain 3, O minThis represents the minimum opening of the shutter curtain 3, and corresponds to the opening degree at which maximum anti-freezing effect is achieved.

[0055] When the relationship is nonlinear, it is expressed as follows: TIFF2026093330000012.tif13170 Here, b is an opening of O min This is a constant term used to adjust the rate of temperature change when the temperature is close to [a certain value].

[0056] In some embodiments, the sensitivity coefficient k to changes in the opening of the shutter curtain 3 is determined through experimental methods.

[0057] Step 1: Select the opening points of the series of shutter curtains 3. These points should cover the range from fully closed to fully open. The experiment should be conducted under stable environmental conditions to minimize the influence of other factors on the outflow water temperature. Only the opening of the shutter curtains 3 should be changed while keeping all other variables (e.g., cooling water flow rate, inlet temperature, ambient temperature, humidity, etc.) constant.

[0058] Step 2: For each predetermined opening degree of the shutter curtain 3, the water outlet temperature of the fin tube bundle of the triangular heat sink is monitored in real time using the temperature sensor 2, and the water outlet temperature data corresponding to each opening degree is recorded.

[0059] Step 3: Record the opening angle and the corresponding outflow temperature data in a graph or table, fit the relationship between the opening angle and outflow temperature using linear regression analysis, and when the optimal fitting line is found by linear regression, the slope of that line is defined as the sensitivity coefficient k.

[0060] In the description of the present invention, the directions or positional relationships indicated by terms such as "center," "vertical," "horizontal," "length," "width," "thickness," "top," "bottom," "front," "back," "left," "right," "perpendicular," "horizontal," "top," "bottom," "inside," "outside," "clockwise," "counterclockwise," "axial direction," "radial direction," and "circumferential direction" are based on the directions or positional relationships shown in the drawings and are merely for the purpose of facilitating the description of the present invention. They do not indicate or imply that the indicated or suggested device or element needs to be configured and operate in a specific direction or orientation, and therefore should not be understood as limitations on the present invention.

[0061] Furthermore, the terms "first" and "second" are merely descriptive and should not be understood as indicating or implying relative importance, or implicitly indicating the number of technical features being described. Therefore, the features defining "first" and "second" may explicitly or implicitly include at least one feature. In the description of this invention, "multiple" means at least two, for example, two, three, etc., unless otherwise specifically limited.

[0062] In this invention, it should be further explained that, unless explicitly stated and limited, terms such as “attachment,” “connection,” “bonding,” and “fixing” should be understood broadly, and may include, for example, a fixed connection, a removable connection, or an integrated connection; a mechanical connection, an electrical connection, a connection that can communicate with one another; a direct connection, an indirect connection via an intermediate medium, a connection within two elements, or an interaction relationship between two elements. Unless otherwise specified, those skilled in the art will be able to understand the specific meaning of the above terms in this invention depending on the specific circumstances.

[0063] In the present invention, unless otherwise specifically defined or limited, when the first feature is located "above" or "below" the second feature, the first and second features may be in direct contact, or they may be indirectly in contact via an intermediate mediator. Furthermore, when the first feature is located "above," "above," or "on the top surface" of the second feature, the first feature is located directly above or diagonally above the second feature, or it simply indicates that the horizontal height of the first feature is higher than that of the second feature. When the first feature is located "below," "below," or "on the bottom surface" of the second feature, the first feature is located directly below or diagonally below the second feature, or it simply indicates that the horizontal height of the first feature is lower than that of the second feature.

[0064] In this invention, terms such as “one embodiment,” “several embodiments,” “example,” “specific example,” or “several examples” mean that certain properties, structures, materials, or features described in relation to at least one embodiment or example of the invention are included. In this specification, the general expressions of the above terms do not necessarily apply to the same embodiment or example. Furthermore, the specific properties, structures, materials, or features described may be combined in appropriate ways in any one or more embodiments or examples. Furthermore, where not inconsistent, those skilled in the art may combine different embodiments or examples and features of different embodiments or examples described herein.

[0065] Although embodiments of the present invention have been shown and explained above, these embodiments are illustrative and should not be understood as limitations to the present invention. Those skilled in the art can change, modify, substitute, and transform the above embodiments within the scope of the present invention. [Explanation of symbols]

[0066] 1 Indirect air cooling tower 2 Temperature sensors 3. Shutter Curtain 4 PLC modules 5 DCS Modules 6. First collection box 7. Second collection box 8 Actuators

Claims

1. A freeze prevention control system for an indirect air-cooled tower, A shutter curtain is installed at the intake port of the triangular radiator of the air-cooling tower to adjust the amount of air intake to the triangular radiator, A temperature sensor is installed on the fin tube of the triangular heat sink of the air-cooling tower to monitor the water outlet temperature of the fin tube, A freeze prevention control system for an indirect air-cooled tower, comprising a control component including a signal acquisition box, a PLC module, and a DCS module, wherein the signal acquisition box is connected to the shutter curtain and the temperature sensor and used to acquire a temperature signal and an actual opening signal of the shutter curtain; the PLC module is connected to the signal acquisition box and used to process the signals and generate a shutter curtain opening signal to be adjusted; and the DCS module is connected to the PLC module and used to receive the shutter curtain opening signal to be adjusted and to control the opening of the shutter curtain by an actuator.

2. The freeze prevention control system for an indirect air-cooled tower according to claim 1, characterized in that the area of ​​the shutter curtain matches the area of ​​the air intake of the triangular radiator, and the shutter curtain can adjust the air intake of the triangular radiator from fully open to fully closed.

3. The indirect air-cooled tower freeze prevention control system according to claim 2, characterized in that there are multiple shutter curtains, and each of the multiple shutter curtains corresponds one-to-one with each of the triangular radiators of the air-cooled tower.

4. The indirect air-cooled tower freeze prevention control system according to claim 1, characterized in that the temperature sensor is located on the wall of the water outlet tube of the outermost fin tube of the triangular heat exchanger of the air-cooled tower.

5. The freeze prevention control system for an indirect air-cooled tower according to claim 4, characterized in that there are multiple temperature sensors, and the multiple temperature sensors are arranged at intervals along the length of the fin tube.

6. A method for controlling the freeze prevention of an indirect air-cooled tower, which is used in the freeze prevention control system for an indirect air-cooled tower according to any one of claims 1 to 5. The steps include: monitoring the water outlet temperature of the outermost fin tube of each triangular heat sink in real time using a temperature sensor; The steps include transmitting the temperature signal and the actual opening degree signal of the shutter curtain to the PLC module, The steps include: processing the signal using a PLC module to generate a shutter curtain opening signal to be adjusted; The steps include transmitting the shutter curtain opening signal to be adjusted to the DCS module, A method for controlling the freeze prevention of an indirect air-cooled tower, comprising the step of controlling the opening degree of a shutter curtain via an actuator using a DCS module.

7. When a PLC module processes a temperature signal, it calibrates the temperature sensor using a standard source with a known temperature, records the sensor's output signal at the standard temperature, and sets or inputs the temperature value corresponding to the standard signal into the PLC module's program. The calibration formula that is satisfied is as follows: The method for controlling the freeze prevention of an indirect air-cooled tower according to claim 6, characterized in that, here, T is the temperature, V is the voltage output of the temperature sensor, and a and b are calibration coefficients.

8. The ambient temperature T is detected by the environmental detection sensor. ｅｎｖ , humidity H ｅｎｖ We monitor and collect weather data as a reference standard for anti-freezing control. The heat dissipation efficiency of the fin tube is linearly related to the ambient temperature, and the outlet water temperature T of the fin tube ｏｕｔ The effect of ambient temperature on this satisfies the following relationship: Here, T ｉｎ This is the temperature of the cooling water entering the fin tube, k １ This is the heat dissipation efficiency coefficient, and T ｂａｓｅ This is the reference ambient temperature, Humidity coefficient k ２ When this is introduced, the effect of humidity on the water outlet temperature of the fin tube satisfies the following relationship: Here, H ｅｎｖ is the environmental humidity, and H ｂａｓｅ is the reference humidity, The anti-freezing control strategy determines the shutter curtain opening degree O based on the combination of ambient temperature and humidity, sets critical conditions, and adjusts the shutter curtain opening degree when the combination of ambient temperature and humidity exceeds these conditions. Here, O ｍａｘ This is the maximum opening of the shutter curtain, O ｍｉｎ This is the minimum opening, T ｔｈ and H ｔｈ These are the threshold values ​​for ambient temperature and humidity, respectively, and k ３ and k ４ The method for controlling the freeze prevention of an indirect air-cooled tower according to claim 7, characterized in that is an adjustment coefficient.

9. The actual opening of the shutter curtain and the water outlet temperature of the triangular radiator satisfy the following relationship: Here, k is the sensitivity coefficient of the water outlet temperature to the change in the opening of the shutter curtain, and represents the degree of response of the temperature change to the change in opening, and b is when the opening is O ｍｉｎ The method for controlling freeze prevention of an indirect air-cooled tower according to claim 8, characterized in that it is a constant term for adjusting the rate of temperature change when it is close to [a certain value].

10. The method for controlling freeze prevention of an indirect air-cooled tower according to claim 9, characterized in that the sensitivity coefficient of the outlet water temperature to changes in the opening degree of the shutter curtain is determined through an experimental method, a series of opening points of the shutter curtain are selected, the opening degree of the shutter curtain is changed while keeping all variables constant, the outlet water temperature of the fin tube bundle of the triangular radiator is monitored in real time for each predetermined opening degree of the shutter curtain, the relationship between the opening degree and the outlet water temperature is fitted by linear regression analysis, and the slope is used as the sensitivity coefficient.

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