Cooling tower optimization sequence control system and method based on cooperation of air volume and energy consumption

Abstract

The invention relates to a cooling tower optimization sequence control system and method based on cooperation of air volume and energy consumption, and the system comprises a cooling tower, a condenser and a cooling water pump, and the cooling tower, the condenser and the cooling water pump are sequentially communicated to form a cooling water loop. The cooling tower is communicated with the cooling water pump through a cooling water return pipe, the cooling water pump is communicated with the condenser through a cooling water return pipe, the cooling tower is communicated with the condenser through a cooling water supply pipe, a temperature sensor is arranged on the cooling water return pipe, and a cooling tower fan with a frequency converter is arranged on the cooling tower. A cooling tower fan optimization sequence control parameter-adding frequency is calculated by establishing an air volume equivalence and energy consumption median algorithm model, and adding or subtracting signals of the cooling tower fans are generated by combining the operation frequency of the cooling tower fans at the current moment so as to adjust the operation number of the cooling tower fans. It is guaranteed that the cooling water outlet temperature is controlled within the set target value range, and the continuity of air volume adjustment and energy consumption saving in the sequence control process are both considered.

Description

Technical Field

[0001] This invention relates to the field of energy-saving control technology for central air conditioning systems, and in particular to an optimized sequence control system and method for cooling towers based on the coordination of air volume and energy consumption. Background Technology

[0002] Driven by the global energy transition and the "dual carbon" goal, energy conservation and emission reduction in the building sector have become an important path to achieving sustainable development. According to relevant research, the energy consumption of HVAC systems accounts for 40% to 60% of building energy consumption, and cooling towers, as key heat dissipation equipment in central air conditioning systems, directly affect the energy consumption and performance of the entire central air conditioning system through the relationship between the operating frequency and the number of operating cooling tower fans.

[0003] In engineering practice, cooling towers are typically selected and designed based on extreme meteorological parameters and full-load conditions. However, central air conditioning systems operate under partial load conditions 90% of the time, and the heat dissipation demand of cooling towers rarely reaches their design requirements. Currently, common cooling tower control strategies include priority frequency control and priority number control. Priority frequency control tends to result in "few units operating at high frequencies" and higher energy consumption at low loads; priority number control, on the other hand, easily leads to frequent fan start-stop cycles, affecting equipment lifespan. Existing technologies struggle to achieve a balance between energy consumption and equipment start-stop frequency, lacking a universally applicable method for setting sequence control parameters that can adapt to different system configurations. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a cooling tower optimization sequence control system and method based on the coordination of air volume and energy consumption, which addresses the shortcomings of the prior art.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A cooling tower optimization sequence control system based on air volume and energy consumption coordination, including a cooling tower, a condenser and a cooling water pump, wherein the cooling tower, condenser and cooling water pump are sequentially connected to form a cooling water circuit, the cooling tower and the cooling water pump and the cooling water pump are respectively connected by cooling water return pipes, the cooling tower and the condenser are connected by cooling water supply pipes, a temperature sensor is installed on the cooling water return pipe, a cooling tower fan with a frequency converter is installed on the cooling tower, and the frequency converter and the temperature sensor are respectively electrically connected to the controller;

[0006] The temperature sensor is used to collect the actual cooling water outlet temperature value in the cooling water return pipe;

[0007] The controller is used to calculate the operating frequency of the cooling tower fan at the current moment based on the target value and the actual value of the cooling water outlet temperature, and output it to the frequency converter; it is also used to generate a fan addition signal or a fan reduction signal based on the calculated fan addition and reduction frequencies and the current operating frequency of the cooling tower fan, and output it to the cooling tower fan to control the gradual increase or decrease of the number of cooling tower fans in operation;

[0008] The frequency converter adjusts the speed of the cooling tower fan according to the current operating frequency of the cooling tower fan.

[0009] The beneficial effects of this invention are as follows: The cooling tower optimized sequence control system based on air volume and energy consumption coordination calculates the cooling tower fan optimized sequence control parameter—the fan addition frequency—by establishing an air volume equivalence and energy consumption median algorithm model. Then, combined with the PI algorithm, the operating frequency of the cooling tower fan at the current moment is calculated based on the cooling water outlet temperature and the set target value. This generates a signal to add or remove cooling tower fans to adjust the number of cooling tower fans in operation, ensuring that the cooling water outlet temperature is controlled within the set target value range. This solves the problems of insufficient high-frequency fans and frequent fan start-stop, thereby significantly reducing the energy consumption of cooling tower fans and achieving energy-saving operation of the central air conditioning cooling system. This invention also takes into account the continuity of air volume adjustment and energy saving during the sequence control process.

[0010] Based on the above technical solution, the present invention can be further improved as follows:

[0011] Furthermore: the controller includes a frequency control module, a start / stop control module, and an accelerator / decelerator frequency control module;

[0012] The frequency control module is used to calculate the operating frequency of the cooling tower fan at the current moment based on the target value and the actual cooling water outlet temperature, and outputs it to the frequency converter and start / stop control module.

[0013] The frequency control module for adding and removing cooling tower fans is used to calculate the frequency for adding and removing fans corresponding to different numbers of cooling tower fans.

[0014] The start / stop control module is used to generate a start / stop signal for the cooling tower fan based on the current operating frequency of the cooling tower fan and the calculated add / remove frequency, combined with a sequence control strategy, and output it to the cooling tower fan to control the number of operating cooling tower fans to increase or decrease one by one.

[0015] The beneficial effects of the above-mentioned further solution are: the operating frequency of the cooling tower fan at the current moment is calculated by the frequency control module, which makes it convenient for the frequency converter to adjust the operating frequency of the cooling tower fan, ensuring that the cooling water outlet temperature is controlled within the set target value range, and significantly reducing the energy consumption of the cooling tower fan.

[0016] Further: The specific implementation of the frequency control module for adding and removing cooling tower fans for different numbers of fans is as follows:

[0017] The frequency reduction is set at the minimum operating frequency of the cooling tower fan;

[0018] The frequency of adding equipment is determined based on the air volume equivalence-energy consumption median method, and the specific calculation formula is as follows:

[0019]

[0020]

[0021]

[0022]

[0023] Among them, f n,add0 f represents the initial frequency of adding n cooling tower fans in the operating mode; min P is the minimum operating frequency of the cooling tower fan. n P represents the total power of n cooling tower fans during operation. rated Where f0 is the rated power of the fan, f0 is the rated frequency of the cooling tower fan, and P is the rated power of the fan. middle f is the median total power of the wind turbines when adjacent numbers of turbines are running. n,add This represents the frequency of adding fans to n cooling towers under different operating modes.

[0024] The beneficial effect of the above further scheme is: firstly, according to the definition of the air volume equivalence method, the total air volume when n+1 fans are running at the lowest frequency is equal to the total air volume when n fans are running at frequency f. n,add0 When the total air volume during operation is equal, the frequency f is obtained. n,add0 This represents the initial frequency of turbine additions under the n-turbine operation mode. Based on this, and according to the relationship between energy consumption and frequency, and using the intermediate values ​​of turbine energy consumption when operating with n and n+1 turbines, the energy consumption model is solved in reverse to obtain f. n,add This refers to the frequency of adding fans in the n-fan operation mode. By achieving air volume equivalence and median energy consumption, it can overcome the technical problems of high energy consumption due to fewer fans operating at high frequency and frequent fan start-stop affecting equipment lifespan in existing technologies, and significantly reduce the energy consumption of cooling tower fans.

[0025] Further: If the frequency of the added machine, calculated according to the air volume equivalence-median energy consumption method, is greater than the upper limit of the frequency of the cooling tower fan, then the upper limit of the frequency of the cooling tower fan shall be used as the frequency of the added machine.

[0026] The beneficial effect of the above-mentioned further solution is that when the calculated frequency of the added machine is greater than the upper limit of the frequency of the cooling tower fan, using the upper limit of the frequency of the cooling tower fan as the added machine frequency can ensure the safe, stable and reliable operation of the cooling tower fan.

[0027] Further: The start / stop control module generates the start / stop signal or reduce / increase signal for the cooling tower fan based on the current operating frequency of the cooling tower fan and the calculated add / remove frequencies, combined with a sequence control strategy. The specific implementation of this is as follows:

[0028] Compare the current operating frequency of the cooling tower fan with the calculated frequency of adding and removing fans;

[0029] When the operating frequency of the cooling tower fan at the current moment is less than or equal to the calculated reduction frequency, it is determined whether the cooling water outlet temperature is within the deviation range of the set target value of the cooling water outlet temperature. If so, no reduction signal is generated, and the number of operating cooling tower fans remains unchanged. Otherwise, a timer is started, and when the duration of the cooling water outlet temperature exceeding the deviation range of the set target value of the cooling water outlet temperature reaches the first preset time threshold, a reduction signal for the cooling tower fan is generated and output to the cooling tower fan.

[0030] When the operating frequency of the cooling tower fan at the current moment is greater than or equal to the calculated additional frequency, a timer is started. When the duration of the operating frequency of the cooling tower fan at the current moment being greater than or equal to the calculated additional frequency reaches the second preset time threshold, an additional signal for the cooling tower fan is generated and output to the cooling tower fan.

[0031] When the operating frequency of the cooling tower fan at the current moment is between the calculated frequency for reducing and increasing the number of fans, no reduction or increase signal will be generated, and the number of operating cooling tower fans will remain unchanged.

[0032] The beneficial effects of the above-mentioned further solutions are as follows: By comparing the current operating frequency of the cooling tower fans with the calculated reduction frequency, and by checking whether the cooling water outlet temperature deviates from the set target value, it is possible to accurately determine whether the system's load-bearing capacity is redundant, thereby reducing the number of operating cooling tower fans. By comparing the current operating frequency of the cooling tower fans with the calculated addition frequency, it is possible to conveniently determine whether the system's load-bearing capacity is insufficient, thereby increasing the number of operating cooling tower fans. This solves the problems of insufficient cooling water outlet temperature and frequent start-stop of fans while ensuring that the cooling water outlet temperature is controlled within the set target value range, thus significantly reducing the energy consumption of cooling tower fans and achieving energy-saving operation of the central air conditioning cooling system.

[0033] This invention also provides a cooling tower optimization sequence control method based on the coordination of airflow and energy consumption. The cooling tower optimization sequence control method based on the coordination of airflow and energy consumption includes the following steps:

[0034] Turn on the central air conditioning cooling tower control system and initialize the operating frequency of the cooling tower fan and the target value of the cooling water outlet temperature.

[0035] The temperature sensor collects the actual cooling water outlet temperature value in the cooling water return pipe;

[0036] The controller calculates the operating frequency of the cooling tower fan at the current moment based on the target value and the actual cooling water outlet temperature, and outputs it to the frequency converter.

[0037] The controller generates a signal to add or remove cooling tower fans based on the calculated frequency of adding and removing fans and the current operating frequency of the cooling tower fans, and outputs it to the cooling tower fans to control the gradual increase or decrease of the number of cooling tower fans in operation.

[0038] The frequency converter adjusts the speed of the cooling tower fan according to the current operating frequency of the cooling tower fan.

[0039] Based on the above technical solution, the present invention can be further improved as follows:

[0040] Further: The controller generates the cooling tower fan's add or remove signal based on the calculated add and remove frequencies and the current operating frequency of the cooling tower fan, specifically including the following steps:

[0041] Calculate the frequency of adding and removing cooling tower fans for different numbers of units;

[0042] Based on the current operating frequency of the cooling tower fan and the calculated frequency of adding and removing fans, and combined with the sequence control strategy, the system generates the signal to add or remove the cooling tower fan, and outputs it to the cooling tower fan to control the number of operating cooling tower fans to increase or decrease one by one.

[0043] The beneficial effect of the above-mentioned further solution is that by comparing the current operating frequency of the cooling tower fan with the calculated frequency of adding and removing fans, it is possible to determine whether to add or remove fans, so as to adjust the number of cooling tower fans in operation in a targeted manner and avoid the problem of frequent start-stop of cooling tower fans.

[0044] Further: The calculation of the frequency of adding and removing cooling tower fans for different numbers of units specifically includes the following steps:

[0045] The frequency reduction is set at the minimum operating frequency of the cooling tower fan;

[0046] The frequency of adding equipment is determined based on the air volume equivalence-energy consumption median method, and the specific calculation formula is as follows:

[0047]

[0048]

[0049]

[0050]

[0051] Among them, f n,add0 f represents the initial frequency of adding n cooling tower fans in the operating mode; min P is the minimum operating frequency of the cooling tower fan. n P represents the total power of n cooling tower fans during operation. rated Where f0 is the rated power of the fan, f0 is the rated frequency of the cooling tower fan, and P is the rated power of the fan. middle f is the median total power of the wind turbines when adjacent numbers of turbines are running. n,add This represents the frequency of adding fans to n cooling towers under different operating modes.

[0052] The beneficial effect of the above further scheme is: firstly, according to the definition of the air volume equivalence method, the total air volume when n+1 fans are running at the lowest frequency is equal to the total air volume when n fans are running at frequency f. n,add0 When the total air volume during operation is equal, the frequency f is obtained. n,add0 This represents the initial frequency of turbine additions under the n-turbine operation mode. Based on this, and according to the relationship between energy consumption and frequency, and using the intermediate values ​​of turbine energy consumption when operating with n and n+1 turbines, the energy consumption model is solved in reverse to obtain f. n,addThis refers to the frequency of adding fans in the n-fan operation mode. By achieving air volume equivalence and median energy consumption, it can overcome the technical problems of high energy consumption due to fewer fans operating at high frequency and frequent fan start-stop affecting equipment lifespan in existing technologies, and significantly reduce the energy consumption of cooling tower fans.

[0053] Further: The step of generating the cooling tower fan's add-on or reduce-off signal based on the current operating frequency of the cooling tower fan and the calculated add-on and reduce-off frequencies, combined with a sequence control strategy, specifically includes the following steps:

[0054] Compare the current operating frequency of the cooling tower fan with the calculated frequency of adding and removing fans;

[0055] When the operating frequency of the cooling tower fan at the current moment is less than or equal to the calculated reduction frequency, it is determined whether the cooling water outlet temperature is within the deviation range of the set target value of the cooling water outlet temperature. If so, no reduction signal is generated, and the number of operating cooling tower fans remains unchanged. Otherwise, a timer is started, and when the duration of the cooling water outlet temperature exceeding the deviation range of the set target value of the cooling water outlet temperature reaches the first preset time threshold, a reduction signal for the cooling tower fan is generated and output to the cooling tower fan.

[0056] When the operating frequency of the cooling tower fan at the current moment is greater than or equal to the calculated additional frequency, a timer is started. When the duration of the operating frequency of the cooling tower fan at the current moment being greater than or equal to the calculated additional frequency reaches the second preset time threshold, an additional signal for the cooling tower fan is generated and output to the cooling tower fan.

[0057] When the operating frequency of the cooling tower fan at the current moment is between the calculated frequency for reducing and increasing the number of fans, no reduction or increase signal will be generated, and the number of operating cooling tower fans will remain unchanged.

[0058] The beneficial effects of the above-mentioned further solutions are as follows: By comparing the current operating frequency of the cooling tower fans with the calculated reduction frequency, and by checking whether the cooling water outlet temperature deviates from the set target value, it is possible to accurately determine whether the system's load-bearing capacity is redundant, thereby reducing the number of operating cooling tower fans. By comparing the current operating frequency of the cooling tower fans with the calculated addition frequency, it is possible to conveniently determine whether the system's load-bearing capacity is insufficient, thereby increasing the number of operating cooling tower fans. This solves the problems of insufficient cooling water outlet temperature and frequent start-stop of fans while ensuring that the cooling water outlet temperature is controlled within the set target value range, thus significantly reducing the energy consumption of cooling tower fans and achieving energy-saving operation of the central air conditioning cooling system. Attached Figure Description

[0059] Figure 1This is a schematic diagram of the structure of a cooling tower optimization sequence control system based on air volume and energy consumption coordination according to an embodiment of the present invention;

[0060] Figure 2a This is a schematic diagram showing the control effect of the cooling tower outlet water temperature and the changes in the number and frequency of the fan in operation under the conventional priority frequency control strategy under low load conditions in Example 1 of the present invention.

[0061] Figure 2b This is a schematic diagram showing the control effect of cooling tower outlet water temperature and the changes in the number and frequency of operating fans under low-load conditions according to the air volume equivalent-energy consumption median method in Example 1 of the present invention.

[0062] Figure 3a This is a schematic diagram showing the control effect of the cooling tower outlet water temperature and the changes in the number and frequency of the fan in operation under the conventional priority frequency control strategy under medium load conditions in Example 1 of the present invention.

[0063] Figure 3b This is a schematic diagram showing the control effect of cooling tower outlet water temperature and the changes in the number and frequency of operating fans under medium load conditions according to the air volume equivalent-energy consumption median method in Example 1 of the present invention.

[0064] Figure 4a This is a schematic diagram illustrating the control effect of the cooling tower outlet water temperature and the changes in the number and frequency of the fan in operation under the conventional priority frequency control strategy under low load conditions in Example 2 of the present invention.

[0065] Figure 4b This is a schematic diagram showing the control effect of cooling tower outlet water temperature and the changes in the number and frequency of operating fans under low-load conditions according to the air volume equivalent-energy consumption median method in Example 2 of the present invention.

[0066] Figure 5a This is a schematic diagram showing the control effect of the cooling tower outlet water temperature and the changes in the number and frequency of the fan in operation under the conventional priority frequency control strategy under medium load conditions in Example 2 of the present invention.

[0067] Figure 5b This is a schematic diagram illustrating the control effect of cooling tower outlet water temperature and the changes in the number and frequency of operating fans under medium load conditions according to the median air volume-energy consumption method in Example 2 of the present invention.

[0068] The attached diagram lists the components represented by each number as follows:

[0069] 1. Cooling tower; 2. Condenser; 3. Cooling water pump; 4. Cooling water return pipe; 5. Cooling water supply pipe; 6. Cooling tower fan; 7. Frequency converter; 8. Temperature sensor; 9. Controller; 10. Frequency control module; 11. Start-stop control module; 12. Increase / decrease frequency control module. Detailed Implementation

[0070] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0071] like Figure 1 As shown, a cooling tower optimization sequence control system based on air volume and energy consumption synergy includes a cooling tower 1, a condenser 2, and a cooling water pump 3. The cooling tower 1, condenser 2, and cooling water pump 3 are sequentially connected to form a cooling water circuit. The cooling tower 1 and cooling water pump 3, as well as the cooling water pump 3 and condenser 2, are connected by cooling water return pipes 4. The cooling tower 1 and condenser 2 are connected by a cooling water supply pipe 5. A temperature sensor 8 is installed on the cooling water return pipe 4. A cooling tower fan 6 with a frequency converter 7 is installed on the cooling tower 1. The frequency converter 7 and the temperature sensor 8 are electrically connected to a controller 9.

[0072] The temperature sensor 8 is used to collect the actual cooling water outlet temperature value in the cooling water return pipe 4.

[0073] In this embodiment, the temperature data acquisition step size is 1 second, and the acquisition is performed periodically when the duration reaches the first and second preset time thresholds to avoid frequent start-stop of the cooling tower fans. Optionally, the acquisition period is preferably 5 minutes. The shorter the acquisition period, the more frequently the cooling tower fans 6 start and stop, which is not conducive to the energy-saving operation of the system. The preferred period of 5 minutes can avoid the high energy consumption of a small number of fans operating at high frequency, and can also avoid the impact of frequent start-stop of fans on equipment lifespan, thus ensuring the balance of the operation of the cooling tower fans 6.

[0074] The controller 9 is used to calculate the operating frequency of the cooling tower fan 6 at the current moment based on the target value and the actual value of the cooling water outlet temperature, and output it to the frequency converter 7; it is also used to generate a fan addition signal or a fan reduction signal for the cooling tower fan 6 based on the calculated fan addition and reduction frequencies and the operating frequency of the cooling tower fan at the current moment, and output it to the cooling tower fan 6 to control the gradual increase or decrease of the number of cooling tower fans 6 in operation;

[0075] The frequency converter 7 adjusts the speed of the cooling tower fan 6 according to the current operating frequency of the cooling tower fan.

[0076] The present invention relates to a cooling tower optimized sequence control system based on airflow and energy consumption coordination. This system calculates the optimal sequence control parameter for cooling tower fans 6—the fan addition frequency—by establishing an airflow equivalence and energy consumption median algorithm model. Then, it combines this with a PI algorithm to calculate the current operating frequency of cooling tower fans 6 based on the cooling water outlet temperature and a set target value, generating a signal to add or remove cooling tower fans 6. This adjusts the number of operating cooling tower fans 6 to ensure the cooling water outlet temperature is controlled within the set target value range. This solves the problems of insufficient high-frequency operation and frequent fan start-stop, thereby significantly reducing the energy consumption of cooling tower fans 6 and achieving energy-saving operation of the central air conditioning cooling system. The invention also considers the continuity of airflow adjustment and energy saving during the sequence control process.

[0077] In one or more embodiments of the present invention, the controller 9 includes a frequency control module 10, a start / stop control module 11, and an adder / subtractor frequency control module 12;

[0078] The frequency control module 10 is used to calculate the operating frequency of the cooling tower fan 6 at the current moment based on the target value of the cooling water outlet temperature and the actual cooling water outlet temperature, and output it to the frequency converter 7 and the start / stop control module 11.

[0079] The frequency control module 12 for adding and removing cooling tower fans 6 is used to calculate the frequency for adding and removing fans for different numbers of fans 6.

[0080] The start / stop control module 11 is used to generate a start / stop signal for the cooling tower fan 6 based on the current operating frequency of the cooling tower fan 6 and the calculated add / remove frequency, and in combination with a sequence control strategy, and output it to the cooling tower fan 6 to control the number of operating cooling tower fans 6 to increase or decrease one by one.

[0081] The frequency control module 10 calculates the operating frequency of the cooling tower fan 6 at the current moment, so that the frequency converter 7 can adjust the operating frequency of the cooling tower fan 6, ensuring that the cooling water outlet temperature is controlled within the set target value range, and significantly reducing the operating energy consumption of the cooling tower fan 6.

[0082] In one or more embodiments of the present invention, the frequency control module 10 calculates the operating frequency of the cooling tower fan 6 at the current moment based on the target value of the cooling water outlet temperature and the actual cooling water outlet temperature value as follows:

[0083] Get the current cooling water outlet temperature and the previous actual cooling water outlet temperature;

[0084] Calculate the first difference e(k) between the current actual cooling water outlet temperature and the set target value of the cooling water outlet temperature, and the second difference e(k-1) between the previous actual cooling water outlet temperature and the set target value of the cooling water outlet temperature;

[0085] The frequency output increment Δu(k) of the cooling tower fan 6 at the current moment is calculated based on the first difference and the second difference, using the following formula:

[0086]

[0087] Among them, K p Here, e(k) is the proportionality coefficient, e(k-1) is the difference between the current actual cooling water outlet temperature and the set target cooling water outlet temperature, and e(k-1) is the difference between the previous actual cooling water outlet temperature and the set target cooling water outlet temperature. s For the sampling period, T i The integration time;

[0088] The operating frequency of the cooling tower fan 6 at the current moment is calculated based on the frequency output increment and the operating frequency of the cooling tower fan 6 at the previous moment.

[0089]

[0090] Where u(k) and u(k-1) are the operating frequencies of the cooling tower fan 6 at the current time and the previous time, respectively.

[0091] First, the difference between the set target value and the actual cooling water outlet temperature at the current and previous moments is calculated. Then, the frequency output increment of the cooling tower fan 6 at the current moment is calculated. Finally, the frequency increment of the cooling tower fan 6 at the current moment is added to the operating frequency of the cooling tower fan 6 at the previous moment to obtain the operating frequency of the cooling tower fan 6 at the current moment. This allows for precise control of the cooling water outlet temperature within the set target value range.

[0092] In one or more embodiments of the present invention, the specific implementation of the addition and reduction frequency control module 12 for calculating the addition and reduction frequencies corresponding to different numbers of cooling tower fans 6 is as follows:

[0093] The frequency reduction is set at the minimum operating frequency of the cooling tower fan 6; in this embodiment, the minimum operating frequency is 20Hz.

[0094] The frequency of adding equipment is determined based on the air volume equivalence-energy consumption median method:

[0095]

[0096]

[0097]

[0098]

[0099] Among them, f n,add0 f represents the initial frequency of adding 6 cooling tower fans in operating mode; min P is the minimum operating frequency of cooling tower fan 6. n P represents the total power output of n cooling tower fans operating at 6. rated Where f0 is the rated power of the fan, f0 is the rated frequency of cooling tower fan 6, and P is the rated power of the fan. middle f is the median total power of the wind turbines when adjacent numbers of turbines are running. n,add This refers to the frequency of adding fans to n cooling towers in operation mode.

[0100] First, according to the definition of the air volume equivalence method, the total air volume when n+1 fans operate at the lowest frequency is equal to the total air volume when n fans operate at frequency f. n,add0 When the total air volume during operation is equal, the frequency f is obtained. n,add0 This represents the initial frequency of turbine additions under the n-turbine operation mode. Based on this, and according to the relationship between energy consumption and frequency, and using the intermediate values ​​of turbine energy consumption when operating with n and n+1 turbines, the energy consumption model is solved in reverse to obtain f. n,add This refers to the frequency of adding fans in the n-fan operation mode. By achieving air volume equivalence and median energy consumption, it can overcome the technical problems of high energy consumption due to fewer fans operating at high frequency and frequent fan start-stop affecting equipment lifespan in the existing technology, and significantly reduce the operating energy consumption of cooling tower fans 6.

[0101] Optionally, in one or more embodiments of the present invention, if the frequency of adding the cooling tower fan 6, calculated according to the air volume equivalence-median energy consumption method, is greater than the upper limit of the frequency of the cooling tower fan 6, then the upper limit of the frequency of the cooling tower fan 6 is used as the frequency of adding the cooling tower fan 6. When the calculated frequency of adding the cooling tower fan 6 is greater than the upper limit of the frequency of the cooling tower fan 6, using the upper limit of the frequency of the cooling tower fan 6 as the frequency of adding the cooling tower fan 6 can ensure the safe, stable, and reliable operation of the cooling tower fan 6.

[0102] The machining frequency f n,add It has a certain range, which is 20Hz to 50Hz, when the calculated f n,add When the frequency exceeds the set upper limit of the fan frequency, then f n,add =50Hz.

[0103] In one or more embodiments of the present invention, the start-stop control module 11 generates the start-up signal or stop-down signal of the cooling tower fan 6 based on the current operating frequency of the cooling tower fan 6 and the calculated add-up frequency and stop-down frequency, and in combination with a sequence control strategy, as follows:

[0104] Compare the current operating frequency of cooling tower fan 6 with the calculated frequency of adding and removing fans;

[0105] When the operating frequency of cooling tower fan 6 at the current moment is less than or equal to the calculated reduction frequency, it is determined whether the cooling water outlet temperature is within the deviation range of the set target value of cooling water outlet temperature. If so, no reduction signal is generated, and the number of operating cooling tower fans 6 remains unchanged. Otherwise, a timer is started, and when the duration of the cooling water outlet temperature exceeding the deviation range of the set target value of cooling water outlet temperature reaches the first preset time threshold, a reduction signal for cooling tower fan 6 is generated and output to the cooling tower fan 6. Here, one fan is reduced at a time. If, after the reduction, the operating frequency of cooling tower fan 6 at the current moment is less than or equal to the calculated reduction frequency and the cooling water outlet temperature is not within the deviation range of the set target value of cooling water outlet temperature, and the duration of the cooling water outlet temperature exceeding the deviation range of the set target value of cooling water outlet temperature reaches the first preset time threshold, then the reduction continues until the last fan is removed.

[0106] When the operating frequency of cooling tower fan 6 at the current moment is greater than or equal to the calculated addition frequency, a timer starts. When the duration of the operating frequency of cooling tower fan 6 at the current moment being greater than or equal to the calculated addition frequency reaches the second preset time threshold, an addition signal for cooling tower fan 6 is generated and output to the cooling tower fan 6. Here, one fan is added at a time. If the operating frequency of cooling tower fan 6 at the current moment is greater than or equal to the calculated addition frequency after the addition, and the duration of the operating frequency of cooling tower fan 6 at the current moment being greater than or equal to the calculated addition frequency reaches the second preset time threshold, the addition continues until the last fan is added.

[0107] When the operating frequency of cooling tower fan 6 is between the calculated frequency for reducing and increasing the number of fans, no reduction or increase signal will be generated, and the number of operating cooling tower fans 6 will remain unchanged.

[0108] By comparing the current operating frequency of cooling tower fan 6 with the calculated reduction frequency, and considering whether the cooling water outlet temperature deviates from the set target value, it is possible to accurately determine whether the system's load-bearing capacity is redundant, thereby reducing the number of cooling tower fans 6 in operation. Conversely, by comparing the current operating frequency of cooling tower fan 6 with the calculated addition frequency, it is possible to conveniently determine whether the system's load-bearing capacity is insufficient, thereby increasing the number of cooling tower fans 6 in operation. This ensures that the cooling water outlet temperature is controlled within the set target value range, solving the problems of insufficient high-frequency operation and frequent start-stop of fans, thus significantly reducing the energy consumption of cooling tower fan 6 and achieving energy-saving operation of the central air conditioning cooling system.

[0109] This invention also provides a cooling tower optimization sequence control method based on the coordination of airflow and energy consumption. The cooling tower optimization sequence control method based on the coordination of airflow and energy consumption includes the following steps:

[0110] Turn on the central air conditioning cooling tower control system and initialize the operating frequency of cooling tower fan 6 and the target value of cooling water outlet temperature.

[0111] Temperature sensor 8 collects the actual cooling water outlet temperature value in the cooling water return pipe 4;

[0112] The controller 9 calculates the operating frequency of the cooling tower fan 6 at the current moment based on the target value and the actual value of the cooling water outlet temperature, and outputs it to the frequency converter 7.

[0113] The controller 9 generates a signal to add or remove cooling tower fans 6 based on the calculated frequency of adding and removing fans and the current operating frequency of the cooling tower fans, and outputs it to the cooling tower fans 6 to control the gradual increase or decrease of the number of cooling tower fans 6 in operation.

[0114] The frequency converter 7 adjusts the speed of the cooling tower fan 6 according to the current operating frequency of the cooling tower fan.

[0115] In one or more embodiments of the present invention, the controller 9 calculates the operating frequency of the cooling tower fan 6 at the current moment based on the target value of the cooling water outlet temperature and the actual cooling water outlet temperature value, specifically including the following steps:

[0116] Get the current cooling water outlet temperature and the previous actual cooling water outlet temperature;

[0117] Calculate the first difference e(k) between the current actual cooling water outlet temperature and the set target value of the cooling water outlet temperature, and the second difference e(k-1) between the previous actual cooling water outlet temperature and the set target value of the cooling water outlet temperature;

[0118] The frequency output increment Δu(k) of the cooling tower fan 6 at the current moment is calculated based on the first difference and the second difference, using the following formula:

[0119]

[0120] Among them, K p Here, e(k) is the proportionality coefficient, e(k-1) is the difference between the current actual cooling water outlet temperature and the set target cooling water outlet temperature, and e(k-1) is the difference between the previous actual cooling water outlet temperature and the set target cooling water outlet temperature. s For the sampling period, T i The integration time;

[0121] The operating frequency of the cooling tower fan 6 at the current moment is calculated based on the frequency output increment and the operating frequency of the cooling tower fan 6 at the previous moment.

[0122]

[0123] Where u(k) and u(k-1) are the operating frequencies of the cooling tower fan 6 at the current time and the previous time, respectively.

[0124] First, the difference between the set target value and the actual cooling water outlet temperature at the current and previous moments is calculated. Then, the frequency output increment of the cooling tower fan 6 at the current moment is calculated. Finally, the frequency increment of the cooling tower fan 6 at the current moment is added to the operating frequency of the cooling tower fan 6 at the previous moment to obtain the operating frequency of the cooling tower fan 6 at the current moment. This allows for precise control of the cooling water outlet temperature within the set target value range.

[0125] In one or more embodiments of the present invention, the controller 9 generates an add-on signal or a reduce-off signal for the cooling tower fan 6 based on the calculated add-on frequency and reduce-off frequency and the current operating frequency of the cooling tower fan 6, specifically including the following steps:

[0126] Calculate the frequency of adding and removing cooling tower fans 6 for different numbers of units;

[0127] Based on the current operating frequency of the cooling tower fan 6 and the calculated frequency of adding and removing fans, and combined with the sequence control strategy, the system generates the signal to add or remove fans for the cooling tower fan 6, and outputs it to the cooling tower fan 6 to control the number of operating fans of the cooling tower fan 6 to increase or decrease one by one.

[0128] By comparing the current operating frequency of cooling tower fan 6 with the calculated frequency of adding and removing fans, it can be determined whether to add or remove fans, so as to adjust the number of cooling tower fans 6 in a targeted manner and avoid the problem of frequent start-stop of cooling tower fans 6.

[0129] In one or more embodiments of the present invention, calculating the frequency of adding and removing cooling tower fans 6 for different numbers specifically includes the following steps:

[0130] The frequency reduction is set at the minimum operating frequency of the cooling tower fan 6;

[0131] The frequency of adding equipment is determined based on the air volume equivalence-energy consumption median method, and the specific calculation formula is as follows:

[0132]

[0133]

[0134]

[0135]

[0136] Among them, f n,add0 The initial frequency of adding fans to n cooling towers (6) in operating mode; f min P is the minimum operating frequency of the cooling tower fan (6). n P is the total power of n cooling tower fans (6) during operation. rated Where f0 is the rated power of the fan, f0 is the rated frequency of the cooling tower fan (6), and P is the rated power of the fan. middle f is the median total power of the wind turbines when adjacent numbers of turbines are running. n,add The frequency of adding fans (6) to n cooling tower fans in the operating mode.

[0137] First, according to the definition of the air volume equivalence method, the total air volume when n+1 fans operate at the lowest frequency is equal to the total air volume when n fans operate at frequency f. n,add0 When the total air volume during operation is equal, the frequency f is obtained. n,add0 This represents the initial frequency of turbine additions under the n-turbine operation mode. Based on this, and according to the relationship between energy consumption and frequency, and using the intermediate values ​​of turbine energy consumption when operating with n and n+1 turbines, the energy consumption model is solved in reverse to obtain f. n,add This refers to the frequency of adding fans in the n-fan operation mode. By achieving air volume equivalence and median energy consumption, this can overcome the technical problems of high energy consumption due to fewer fans operating at high frequency and frequent fan start-stop affecting equipment lifespan in existing technologies, and significantly reduce the operating energy consumption of cooling tower fans 6.

[0138] In one or more embodiments of the present invention, the step of generating the cooling tower fan 6's add-on signal or reduce-on signal based on the current operating frequency of the cooling tower fan 6 and the calculated add-on and reduce-on frequencies, combined with a sequence control strategy, specifically includes the following steps:

[0139] Compare the current operating frequency of cooling tower fan 6 with the calculated frequency of adding and removing fans;

[0140] When the operating frequency of the cooling tower fan 6 at the current moment is less than or equal to the calculated reduction frequency, it is determined whether the cooling water outlet temperature value is within the deviation range of the set target value of the cooling water outlet temperature. If so, no reduction signal is generated, and the number of operating cooling tower fans 6 remains unchanged. Otherwise, a timer is started, and when the duration of the cooling water outlet temperature value exceeding the deviation range of the set target value of the cooling water outlet temperature reaches the first preset time threshold, a reduction signal for the cooling tower fan 6 is generated and output to the cooling tower fan 6.

[0141] When the operating frequency of the cooling tower fan 6 at the current moment is greater than or equal to the calculated additional frequency, the timer starts, and when the duration of the operating frequency of the cooling tower fan 6 at the current moment being greater than or equal to the calculated additional frequency reaches the second preset time threshold, an additional signal for the cooling tower fan 6 is generated and output to the cooling tower fan 6.

[0142] When the operating frequency of cooling tower fan 6 is between the calculated frequency for reducing and increasing the number of fans, no reduction or increase signal will be generated, and the number of operating cooling tower fans 6 will remain unchanged.

[0143] By comparing the current operating frequency of cooling tower fan 6 with the calculated reduction frequency, and considering whether the cooling water outlet temperature deviates from the set target value, it is possible to accurately determine whether the system's load-bearing capacity is redundant, thereby reducing the number of cooling tower fans 6 in operation. Conversely, by comparing the current operating frequency of cooling tower fan 6 with the calculated addition frequency, it is possible to conveniently determine whether the system's load-bearing capacity is insufficient, thereby increasing the number of cooling tower fans 6 in operation. This ensures that the cooling water outlet temperature is controlled within the set target value range, solving the problems of insufficient high-frequency operation and frequent start-stop of fans, thus significantly reducing the energy consumption of cooling tower fan 6 and achieving energy-saving operation of the central air conditioning cooling system.

[0144] Example 1:

[0145] The system is configured with two chiller units, each with a rated cooling capacity of 1055 kW and a rated power of 186.6 kW; two fixed-frequency cooling water pumps, each with a design flow rate of 59 kg / s and a rated power of 22 kW; and four cooling towers, each equipped with a 5.5 kW fan. All cooling tower trays are connected via connecting pipes, and all fans are equipped with frequency converters. The system's operating time period is 00:00–24:00, with a simulation step of 1 second and a data acquisition period of 1 second. The meteorological parameters and load data for each region in the system's March and June operating data are used as typical daily load conditions for low, medium, and high loads, respectively. The chilled water supply temperature is set to 7℃, and the target values ​​for the cooling tower outlet water temperature under low, medium, and high load conditions are set to 25℃, 28℃, and 30℃, respectively.

[0146] The control performance of the conventional priority frequency control strategy and the air volume equivalent-energy consumption median method were tested under different load conditions. The PI control parameter of the frequency converter for both strategies was K. p =2,T i =200s, the frequency of the cooling tower is 20Hz, the timing time for the cooling tower is 5min, and the deviation between the cooling tower outlet water temperature and the set target value is 0.5℃ under the cooling tower cooling condition.

[0147] Under low load conditions, the control effect of cooling tower outlet water temperature and the changes in the number and frequency of operating fans are as follows: Figures 2a-2b As shown, where Figure 2a This diagram illustrates the control effect of the conventional priority frequency control strategy on the cooling tower outlet water temperature under low load conditions, as well as the changes in the number and frequency of operating fans. Figure 2b This diagram illustrates the control effect of cooling tower outlet water temperature and the changes in the number and frequency of operating fans under low-load conditions, corresponding to the air volume equivalent-energy consumption median method.

[0148] Under medium load conditions, the control effect of cooling tower outlet water temperature and the changes in the number and frequency of operating fans are as follows: Figures 3a-3b As shown, where Figure 3a This diagram illustrates the control effect of the conventional priority frequency control strategy on the cooling tower outlet water temperature and the changes in the number and frequency of operating fans under medium load conditions. Figure 3b This diagram illustrates the control effect of cooling tower outlet water temperature and the changes in the number and frequency of operating fans under medium load conditions, corresponding to the air volume equivalent-energy consumption median method.

[0149] Under high load conditions, the cooling tower fans of the system remain fully operational and operate at a high frequency without any addition or removal of fans. Therefore, the sequence control parameters have no significant impact on the fan start-up and shutdown frequency and system energy consumption.

[0150] Example 2

[0151] The system is configured with 3 chiller units, each with a rated cooling capacity of 4090 kW and a rated power of 682.8 kW; 3 fixed-frequency cooling water pumps, each with a design flow rate of 227.29 kg / s and a rated power of 90 kW; and 10 cooling towers, each equipped with one 11 kW rated fan. All cooling tower trays are connected via connecting pipes, and all fans are equipped with frequency converters. The system's operating time period is 00:00–24:00, with a simulation step of 1 second and a data acquisition period of 1 second. The meteorological parameters and load data for each region in the system's March and June operating data are used as typical daily load conditions for low, medium, and high loads, respectively. The chilled water supply temperature is set to 7℃, and the target values ​​for the cooling tower outlet water temperature under low, medium, and high load conditions are set to 25℃, 28℃, and 30℃, respectively.

[0152] The control performance of the conventional priority frequency control strategy and the air volume equivalent-energy consumption median method were tested under different load conditions. The PI control parameter of the frequency converter for both strategies was K. p =2,T i =200s, the frequency of the cooling tower is 20Hz, the timing time for the cooling tower is 5min, and the deviation between the cooling tower outlet water temperature and the set target value is 0.5℃ under the cooling tower cooling condition.

[0153] Under low load conditions, the control effect of cooling tower outlet water temperature and the changes in the number and frequency of operating fans are as follows: Figures 4a-4b As shown, where Figure 4a This diagram illustrates the control effect of the conventional priority frequency control strategy on the cooling tower outlet water temperature under low load conditions, as well as the changes in the number and frequency of operating fans. Figure 4b This diagram illustrates the control effect of cooling tower outlet water temperature and the changes in the number and frequency of operating fans under low-load conditions, corresponding to the air volume equivalent-energy consumption median method.

[0154] Under medium load conditions, the control effect of cooling tower outlet water temperature and the changes in the number and frequency of operating fans are as follows: Figures 5a-5b As shown, where Figure 5a This diagram illustrates the control effect of the conventional priority frequency control strategy on the cooling tower outlet water temperature and the changes in the number and frequency of operating fans under medium load conditions. Figure 5b This diagram illustrates the control effect of cooling tower outlet water temperature and the changes in the number and frequency of operating fans under medium load conditions, corresponding to the air volume equivalent-energy consumption median method.

[0155] Under high load conditions, the cooling tower fans of the system remain fully operational and operate at a high frequency without any addition or removal of fans. Therefore, the sequence control parameters have no significant impact on the fan start-up and shutdown frequency and system energy consumption.

[0156] In summary, the control method of the cooling tower optimized sequence control system with coordinated air volume and energy consumption of the present invention demonstrates that, under medium and low load conditions, the air volume equivalence-energy consumption median method can significantly reduce the energy consumption of the cooling tower fan, and the energy-saving effect is more significant at lower loads.

[0157] Table 1. Cooling tower energy consumption and fan start / stop frequency under different control strategies

[0158]

[0159] The cooling tower optimization sequence control method proposed in this invention, based on the coordination of air volume and energy consumption, does not depend on the specific system configuration, number of units, or equipment parameters, and has strong universality, providing an efficient and universal optimization sequence control method for cooling tower systems with different configurations.

[0160] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cooling tower optimized sequence control system based on the synergy of airflow and energy consumption, characterized in that: The cooling tower (1), condenser (2) and cooling water pump (3) are connected in sequence to form a cooling water circuit. The cooling tower (1) and cooling water pump (3) are connected to each other and the cooling water pump (3) and condenser (2) are connected by cooling water return pipe (4). The cooling tower (1) and condenser (2) are connected by cooling water supply pipe (5). A temperature sensor (8) is installed on the cooling water return pipe (4). A cooling tower fan (6) with frequency converter (7) is installed on the cooling tower (1). The frequency converter (7) and temperature sensor (8) are electrically connected to controller (9). The temperature sensor (8) is used to collect the actual cooling water outlet temperature value in the cooling water return pipe (4); The controller (9) is used to calculate the operating frequency of the cooling tower fan (6) at the current moment based on the target value and the actual value of the cooling water outlet temperature, and output it to the frequency converter (7); it is also used to generate the cooling tower fan (6)'s add or subtract signal based on the calculated add and subtract frequency and the current operating frequency of the cooling tower fan, and output it to the cooling tower fan (6) to control the number of cooling tower fans (6) operating one by one; The frequency converter (7) adjusts the speed of the cooling tower fan (6) according to the operating frequency of the cooling tower fan at the current moment.

2. The cooling tower optimization sequence control system based on air volume and energy consumption coordination according to claim 1, characterized in that: The controller (9) includes a frequency control module (10), a start / stop control module (11), and an adder / subtractor frequency control module (12). The frequency control module (10) is used to calculate the operating frequency of the cooling tower fan (6) at the current moment based on the target value of the cooling water outlet temperature and the actual cooling water outlet temperature, and output it to the frequency converter (7) and the start / stop control module (11). The frequency control module (12) for adding and removing cooling tower fans (6) of different numbers is used to calculate the frequency for adding and removing fans. The start / stop control module (11) is used to generate a start / stop signal or a stop / stop signal for the cooling tower fan (6) based on the current operating frequency of the cooling tower fan (6) and the calculated start / stop frequency, and in combination with the sequence control strategy, and output it to the cooling tower fan (6) to control the number of operating cooling tower fans (6) to increase or decrease one by one.

3. The cooling tower optimization sequence control system based on airflow and energy consumption synergy according to claim 2, characterized in that: The specific implementation of the frequency control module (12) for calculating the frequency of adding and removing cooling tower fans (6) for different numbers of fans is as follows: The frequency reduction is set at the minimum operating frequency of the cooling tower fan (6); The frequency of adding equipment is determined based on the air volume equivalence-energy consumption median method, and the specific calculation formula is as follows: ； ； ； ； Wherein, f n,add0 is the preliminary frequency of adding n cooling tower fans (6) in the running mode; f min is the minimum running frequency of the cooling tower fan (6), P n is the total power of n cooling tower fans (6) in operation, P rated is the rated power of the fan, f0 is the rated frequency of the cooling tower fan (6), P middle is the intermediate value of the total power of the fan when the adjacent number of fans are running, f n,add is the frequency of adding n cooling tower fans (6) in the running mode.

4. The cooling tower optimization sequence control system based on airflow and energy consumption synergy according to claim 3, characterized in that: The start / stop control module (11) generates the start / stop signal or the shutdown signal of the cooling tower fan (6) based on the current operating frequency of the cooling tower fan (6) and the calculated start / stop frequency, and in combination with the sequence control strategy. The specific implementation is as follows: Compare the current operating frequency of the cooling tower fan (6) with the calculated frequency of adding and removing fans; When the operating frequency of the cooling tower fan (6) at the current moment is less than or equal to the calculated reduction frequency, it is determined whether the cooling water outlet temperature value is within the deviation range of the cooling water outlet temperature target value. If so, no reduction signal is generated, and the number of cooling tower fans (6) in operation remains unchanged. Otherwise, timing begins, and when the duration of the cooling water outlet temperature value exceeding the deviation range of the cooling water outlet temperature target value reaches the first preset time threshold, a reduction signal for the cooling tower fan (6) is generated and output to the cooling tower fan (6). When the operating frequency of the cooling tower fan (6) at the current moment is greater than or equal to the calculated additional frequency, the timing starts, and when the duration of the operating frequency of the cooling tower fan (6) at the current moment being greater than or equal to the calculated additional frequency reaches the second preset time threshold, an additional signal for the cooling tower fan (6) is generated and output to the cooling tower fan (6). When the operating frequency of the cooling tower fan (6) at the current moment is between the calculated frequency of reducing the number of fans and the frequency of increasing the number of fans, no signal of reducing the number of fans or increasing the number of fans will be generated, and the number of operating cooling tower fans (6) will remain unchanged.

5. A cooling tower optimization sequence control method based on airflow and energy consumption coordination, employing the cooling tower optimization sequence control method based on airflow and energy consumption coordination as described in any one of claims 1-4, characterized in that, Includes the following steps: Turn on the central air conditioning cooling tower control system and initialize the operating frequency of the cooling tower fan (6) and the target value of the cooling water outlet temperature. Temperature sensor (8) collects the actual cooling water outlet temperature value in the cooling water return pipe (4); The controller (9) calculates the operating frequency of the cooling tower fan (6) at the current moment based on the target value of the cooling water outlet temperature and the actual cooling water outlet temperature, and outputs it to the frequency converter (7). The controller (9) generates a signal for adding or removing cooling tower fans (6) based on the calculated frequency of adding and removing fans and the operating frequency of the cooling tower fans at the current moment, and outputs it to the cooling tower fans (6) to control the number of cooling tower fans (6) operating one by one. The frequency converter (7) adjusts the speed of the cooling tower fan (6) according to the operating frequency of the cooling tower fan at the current moment.

6. The cooling tower optimization sequence control method based on air volume and energy consumption synergy according to claim 5, characterized in that: The controller (9) generates the cooling tower fan (6)'s add or remove signal based on the calculated add and remove frequency and the current operating frequency of the cooling tower fan. Specifically, this includes the following steps: Calculate the frequency of adding and removing cooling tower fans (6) for different numbers of fans; Based on the current operating frequency of the cooling tower fan (6) and the calculated frequency of adding and removing fans, and combined with the sequence control strategy, the fan adding or removing signal of the cooling tower fan (6) is generated and output to the cooling tower fan (6) to control the number of cooling tower fans (6) to increase or decrease one by one.

7. The cooling tower optimization sequence control method based on air volume and energy consumption synergy according to claim 6, characterized in that: The calculation of the frequency of adding and removing cooling tower fans (6) for different numbers of units specifically includes the following steps: The frequency reduction is set at the minimum operating frequency of the cooling tower fan (6); The frequency of adding equipment is determined based on the air volume equivalence-energy consumption median method, and the specific calculation formula is as follows: ； ； ； ； Among them, f n,add0 The initial frequency of additional units for n cooling tower fans (6) in operating mode; f min P is the minimum operating frequency of the cooling tower fan (6). n P is the total power of n cooling tower fans (6) during operation. rated Where f0 is the rated power of the fan, f0 is the rated frequency of the cooling tower fan (6), and P is the rated power of the fan. middle f is the median total power of the wind turbines when adjacent numbers of turbines are running. n,add The frequency of adding fans (6) to the n cooling tower fans in the operating mode.

8. The cooling tower optimization sequence control method based on air volume and energy consumption synergy according to claim 6, characterized in that: The process of generating the cooling tower fan (6)'s on / off signal based on the current operating frequency of the cooling tower fan (6) and the calculated on / off frequency, combined with a sequence control strategy, specifically includes the following steps: Compare the current operating frequency of the cooling tower fan (6) with the calculated frequency of adding and removing fans; When the operating frequency of the cooling tower fan (6) at the current moment is less than or equal to the calculated reduction frequency, it is determined whether the cooling water outlet temperature value is within the deviation range of the cooling water outlet temperature target value. If so, no reduction signal is generated, and the number of cooling tower fans (6) in operation remains unchanged. Otherwise, timing begins, and when the duration of the cooling water outlet temperature value exceeding the deviation range of the cooling water outlet temperature target value reaches the first preset time threshold, a reduction signal for the cooling tower fan (6) is generated and output to the cooling tower fan (6). When the operating frequency of the cooling tower fan (6) at the current moment is greater than or equal to the calculated additional frequency, the timing starts, and when the duration of the operating frequency of the cooling tower fan (6) at the current moment being greater than or equal to the calculated additional frequency reaches the second preset time threshold, an additional signal for the cooling tower fan (6) is generated and output to the cooling tower fan (6). When the operating frequency of the cooling tower fan (6) at the current moment is between the calculated frequency of reducing the number of fans and the frequency of increasing the number of fans, no signal of reducing the number of fans or increasing the number of fans will be generated, and the number of operating cooling tower fans (6) will remain unchanged.

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