A central air conditioning cooling tower control system and method

Abstract

This invention relates to a central air conditioning cooling tower control system and method. The system includes a cooling water circuit formed by a cooling tower, a condenser, and a cooling water pump connected in sequence, and a controller. The cooling tower and condenser are connected via a cooling water supply pipe, and the cooling tower and cooling water pump, as well as the cooling water pump and condenser, are connected via cooling water return pipes. A temperature sensor is installed on the cooling water return pipe. A cooling tower fan is installed on the cooling tower, and the cooling tower fan is equipped with a frequency converter. The frequency converter and the temperature sensor are electrically connected to the controller. By optimizing the operating frequency to control the speed of the cooling tower fan, the relationship between the number of operating cooling tower fans and the operating frequency is coordinated. The optimized operating frequency of the cooling tower fan can be automatically adjusted according to the real-time return water temperature, improving the automation level of the entire system. While controlling the cooling water return temperature within the target range, it can reduce system energy consumption and achieve energy-saving operation of the central air conditioning cooling water system.

Description

Technical Field

[0001] This invention relates to the field of energy-saving control technology for central air conditioning, and in particular to a central air conditioning cooling tower control system and method. Background Technology

[0002] In a central air conditioning cooling water system, cooling water exchanges heat with the refrigerant in the condenser of the chiller unit, carrying away heat and raising its temperature. It then flows to the cooling tower to exchange heat with the outdoor air, expelling heat outdoors and lowering its temperature before circulating back to the chiller unit's condenser. During this process, the return water temperature (i.e., the cooling tower outlet temperature) must be controlled within a target range to ensure the safe operation of the chiller unit and energy-efficient operation of the system. In practical engineering, the return water temperature is generally controlled by the number of cooling towers started and stopped or the operating frequency of the cooling tower fans. Maintaining the return water temperature within the target range by controlling either the number of cooling towers started and stopped or the operating frequency of the cooling tower fans is generally feasible. Currently, there are many control strategies for the number of cooling towers started and stopped and the operating frequency of the cooling tower fans. Different control strategies result in significant differences in the energy consumption of the cooling towers. Currently, there is no truly effective solution to coordinate the relationship between the number of cooling towers and the frequency, leading to the common practice in practical engineering of using a control method with fewer cooling towers and higher frequencies, resulting in consistently high energy consumption for cooling tower operation. Therefore, developing an optimized control strategy for central air conditioning cooling towers is of great significance for reducing the energy consumption of cooling tower operation.

[0003] Given the aforementioned technical background, the coordination relationship between the number of operating cooling towers and their operating frequency is complex. The control method of using a small number of towers at a high frequency is often adopted, which results in consistently high energy consumption of cooling towers and fails to fully meet the needs of building energy conservation and consumption reduction. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a central air conditioning cooling tower control system and method. This control system and method can maximize energy savings in cooling tower fan operation by coordinating the operating frequency and number of fans in operation, while keeping the cooling water return temperature within the target range.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A central air conditioning cooling tower control system includes a cooling water circuit formed by a cooling tower, a condenser and a cooling water pump connected in sequence and a controller. The cooling tower and the condenser are connected by a cooling water supply pipe. The cooling tower and the cooling water pump and the cooling water pump and the condenser are respectively connected by cooling water return pipes. A temperature sensor is installed on the cooling water return pipe. A cooling tower fan is installed on the cooling tower. The cooling tower fan is equipped with a frequency converter. The frequency converter and the temperature sensor are electrically connected to the controller.

[0006] The temperature sensor is used to collect the real-time return water temperature value of the cooling water in the cooling water return pipe and output it to the controller.

[0007] The controller is used to determine the optimal operating frequency of the cooling tower fan based on the real-time return water temperature value of the cooling water and the preset return water temperature control target value of the cooling water, and is also used to generate a signal to add or remove cooling tower fans based on the optimized operating frequency and the current number of cooling tower fans in operation.

[0008] The frequency converter is used to control the speed of the cooling tower fan according to the optimized operating frequency or the output value of the previous operating frequency, and to control the number of operating cooling tower fans to increase or decrease according to the add or reduce signal, so as to adjust the real-time return water temperature value of the cooling water to be dynamically constant within the preset deviation range of the preset cooling water return water temperature control target value.

[0009] The beneficial effects of this invention are as follows: The central air conditioning cooling tower control system of this invention collects the real-time return water temperature value of the cooling water in the cooling water return pipe through the temperature sensor, and the controller determines the optimized operating frequency of the cooling tower fan based on the real-time return water temperature value and the preset cooling water return water temperature control target value, and further determines the required number of cooling tower fans to operate, so as to generate a signal to add or remove cooling tower fans. The speed of the cooling tower fan is controlled by the optimized operating frequency, and the relationship between the number of cooling tower fans operating and the operating frequency is coordinated. The optimized operating frequency of the cooling tower fan can be automatically adjusted according to the real-time return water temperature of the cooling water, and the number of cooling tower fans operating can be controlled according to the calculated optimized operating frequency of the cooling tower fan, which improves the automation level of the entire system. While controlling the cooling water return water temperature within the target range, it can also reduce system energy consumption and achieve energy-saving operation of the central air conditioning cooling water system.

[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 and a start / stop control module;

[0012] The frequency control module is used to compare the preset target value of the cooling water return temperature control with the real-time return temperature value of the cooling water, and determine whether the real-time return temperature value of the cooling water is within the preset deviation range of the preset target value of the cooling water return temperature control. If it is, the inverter's operating frequency is controlled to remain unchanged from the previous operating frequency output value; otherwise, the optimized operating frequency of the cooling tower fan is calculated based on the real-time return temperature value of the cooling water and the preset target value of the cooling water return temperature control, and output to the inverter.

[0013] The start / stop control module is used to generate a signal to add or remove cooling tower fans based on the optimized operating frequency and the current number of operating cooling tower fans, and output the signal to the frequency converter.

[0014] The beneficial effects of the above-mentioned further solution are as follows: the frequency control module determines whether the real-time return water temperature value of the cooling water exceeds the preset return water temperature control target value, thereby determining whether to optimize the operating frequency of the cooling tower fan. When the real-time return water temperature value of the cooling water exceeds the preset return water temperature control target value, the module directly calculates the optimized operating frequency of the cooling tower fan based on the real-time return water temperature value and the preset return water temperature control target value, thereby adjusting the speed of the cooling tower fan. Finally, in conjunction with the start-stop control module, the module adjusts the real-time return water temperature value of the cooling water to dynamically remain constant within the preset deviation range of the preset return water temperature control target value.

[0015] Further: The specific implementation of the start / stop control module generating the cooling tower fan increase or decrease signal based on the optimized operating frequency and the current number of operating cooling tower fans is as follows:

[0016] When the cooling tower fans are not all running, the optimized operating frequency range is 25-45Hz.

[0017] When the operating frequency of the cooling tower fan exceeds the preset frequency threshold range, it is determined whether the real-time return water temperature value is greater than the cooling water return water temperature deviation threshold and continues for a first preset time. If so, a cooling tower fan boosting signal is generated and output to the frequency converter.

[0018] When the operating frequency of the cooling tower fan is less than or equal to the preset reduction frequency threshold range, it is determined whether the real-time return water temperature value is less than the cooling water return water temperature deviation threshold and continues for a second preset time. If so, a reduction signal for the cooling tower fan is generated and output to the frequency converter.

[0019] When the operating frequency of the cooling tower fan is greater than the preset reduction frequency threshold range but less than the preset increase frequency threshold range, the existing number of cooling tower fans shall be maintained.

[0020] When all the cooling tower fans are running, the optimized operating frequency range is 25-50Hz.

[0021] When the operating frequency of the cooling tower fan is less than or equal to the preset reduction frequency threshold range, it is determined whether the real-time return water temperature value is less than the cooling water return water temperature deviation threshold and continues for a second preset time. If so, a reduction signal for the cooling tower fan is generated and output to the frequency converter.

[0022] If the operating frequency of the cooling tower fan is greater than the preset reduction frequency threshold range but less than the preset increase frequency threshold range, the existing number of cooling tower fans will be maintained.

[0023] The beneficial effects of the above-mentioned further solution are as follows: by comparing the optimized operating frequency with the preset reduction frequency threshold and the addition frequency threshold, it can be determined whether the current operating frequency of the cooling tower fan can meet the adjustment requirements. When the frequency exceeds the preset addition frequency threshold or is less than the preset reduction frequency threshold and exceeds the corresponding preset temperature deviation threshold for a preset duration, the number of operating cooling tower fans is adjusted respectively. This coordinates the relationship between the number of operating cooling tower fans and the operating frequency. The optimized operating frequency of the cooling tower fan can be automatically adjusted according to the real-time return water temperature of the cooling water, so as to achieve the purpose of dynamically keeping the real-time return water temperature value within the preset deviation range of the preset cooling water return water temperature control target value.

[0024] Further: When the real-time return water temperature of the cooling water is less than the preset limit temperature threshold, it is determined that the real-time return water temperature of the cooling water is incorrect, and the operating frequency of the inverter is controlled to maintain the previous output value unchanged.

[0025] The beneficial effect of the above-mentioned further solution is that by setting a preset limit temperature threshold for the real-time return water temperature value, it can be determined that the real-time return water temperature value is incorrect when the real-time return water temperature value is less than the preset limit temperature threshold. At this time, the system will no longer respond according to the incorrect real-time return water temperature value, and the operating frequency of the cooling tower fan will remain unchanged from the previous output value to maintain the stability of the entire system.

[0026] Furthermore: the range of the optimized operating frequency is from the upper frequency limit to the lower frequency limit;

[0027] When the optimized operating frequency is greater than the upper frequency limit, the optimized operating frequency is determined to be equal to the upper frequency limit.

[0028] When the calculated optimized operating frequency is less than the lower frequency limit, the optimized operating frequency is determined to be equal to the lower frequency limit value.

[0029] The beneficial effect of the above-mentioned further solution is that by setting the upper and lower limits of the optimized operating frequency, a certain safety margin can be left, which can ensure the safety and stability of the entire system.

[0030] The present invention also provides a central air conditioning cooling tower control method, which employs the aforementioned central air conditioning cooling tower control system and includes the following steps:

[0031] S1: 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 return temperature control.

[0032] S2: Collect the real-time return water temperature value of the cooling water in the cooling water return pipe, and determine whether the real-time return water temperature value of the cooling water is within the preset deviation range of the preset cooling water return water temperature control target value. If so, control the working frequency of the inverter to maintain the previous working frequency output value unchanged; otherwise, proceed to S3.

[0033] S3: Calculate the optimized operating frequency of the cooling tower fan based on the real-time return water temperature value of the cooling water and the preset return water temperature control target value of the cooling water, and generate a signal to add or remove cooling tower fans based on the optimized operating frequency and the current number of cooling tower fans in operation.

[0034] S4: The frequency converter controls the speed of the cooling tower fan according to the optimized operating frequency or the output value of the previous operating frequency, and controls the number of operating cooling tower fans to increase or decrease according to the add or remove signal, so as to adjust the real-time return water temperature value of the cooling water to be dynamically constant within the preset deviation range of the preset cooling water return water temperature control target value.

[0035] The central air conditioning cooling tower control method of the present invention collects the real-time return water temperature value of the cooling water in the cooling water return pipe through the temperature sensor, and determines the optimized operating frequency of the cooling tower fan based on the real-time return water temperature value and the preset cooling water return water temperature control target value, and further determines the required number of cooling tower fans to operate, so as to generate a signal to add or remove cooling tower fans. The speed of the cooling tower fan is controlled by the optimized operating frequency, and the relationship between the number of cooling tower fans operating and the operating frequency is coordinated. The optimized operating frequency of the cooling tower fan can be automatically adjusted according to the real-time return water temperature, and the number of cooling tower fans operating can be controlled according to the calculated optimized operating frequency of the cooling tower fan, which improves the automation level of the entire system, controls the cooling water return water temperature within the target range, and reduces system energy consumption, thereby achieving energy-saving operation of the central air conditioning cooling water system.

[0036] Based on the above technical solution, the present invention can be further improved as follows:

[0037] Further: In step S4, generating a signal to add or remove cooling tower fans based on the optimized operating frequency and the current number of operating cooling tower fans specifically includes the following steps:

[0038] When the cooling tower fans are not all running, the optimized operating frequency range is 25-45Hz.

[0039] When the operating frequency of the cooling tower fan exceeds the preset frequency threshold range, it is determined whether the real-time return water temperature value is greater than the cooling water return water temperature deviation threshold and continues for a first preset time. If so, a cooling tower fan boosting signal is generated and output to the frequency converter.

[0040] When the operating frequency of the cooling tower fan is less than or equal to the preset reduction frequency threshold range, it is determined whether the real-time return water temperature value is less than the cooling water return water temperature deviation threshold and continues for a second preset time. If so, a reduction signal for the cooling tower fan is generated and output to the frequency converter.

[0041] When the operating frequency of the cooling tower fan is greater than the preset reduction frequency threshold range but less than the preset increase frequency threshold range, the existing number of cooling tower fans shall be maintained.

[0042] When all the cooling tower fans are running, the optimized operating frequency range is 25-50Hz.

[0043] When the operating frequency of the cooling tower fan is less than or equal to the preset reduction frequency threshold range, it is determined whether the real-time return water temperature value is less than the cooling water return water temperature deviation threshold and continues for a second preset time. If so, a reduction signal for the cooling tower fan is generated and output to the frequency converter.

[0044] If the operating frequency of the cooling tower fan is greater than the preset reduction frequency threshold range but less than the preset increase frequency threshold range, the existing number of cooling tower fans will be maintained.

[0045] The beneficial effects of the above-mentioned further solution are as follows: by comparing the optimized operating frequency with the preset reduction frequency threshold and the addition frequency threshold, it can be determined whether the current operating frequency of the cooling tower fan can meet the adjustment requirements. When the frequency exceeds the preset addition frequency threshold or is less than the preset reduction frequency threshold and exceeds the corresponding preset temperature deviation threshold for a preset duration, the number of operating cooling tower fans is adjusted respectively. This coordinates the relationship between the number of operating cooling tower fans and the operating frequency. The optimized operating frequency of the cooling tower fan can be automatically adjusted according to the real-time return water temperature of the cooling water, so as to achieve the purpose of dynamically keeping the real-time return water temperature value within the preset deviation range of the preset cooling water return water temperature control target value.

[0046] The present invention also provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores computer instructions, which are used to cause a processor to execute the central air conditioning cooling tower control method.

[0047] The present invention also provides a central air conditioning cooling tower control device, the central air conditioning cooling tower control device comprising:

[0048] At least one processor and a storage medium, wherein the memory is communicatively connected to the processor;

[0049] The storage medium stores a computer program that can be executed by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to execute the central air conditioning cooling tower control method. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the structure of a central air conditioning cooling tower control system according to an embodiment of the present invention;

[0051] Figure 2 This is a schematic diagram of the controller according to an embodiment of the present invention;

[0052] Figure 3 This is a schematic flowchart of a central air conditioning cooling tower control method according to an embodiment of the present invention.

[0053] The attached diagram lists the components represented by each number as follows:

[0054] 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. Detailed Implementation

[0055] 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.

[0056] like Figure 1 As shown, a central air conditioning cooling tower control system includes a cooling water circuit formed by a cooling tower 1, a condenser 2, and a cooling water pump 3 connected in sequence, and a controller 9. The cooling tower 1 and the condenser 2 are connected by a cooling water supply pipe 5. The cooling tower 1 and the cooling water pump 3, as well as the cooling water pump 3 and the condenser 2, are connected by cooling water return pipes 4. A temperature sensor 8 is installed on the cooling water return pipe 4. A cooling tower fan 6 is installed on the cooling tower 1. The cooling tower fan 6 is equipped with a frequency converter 7. The frequency converter 7 and the temperature sensor 8 are electrically connected to the controller 9.

[0057] The temperature sensor 8 is used to collect the real-time return water temperature value of the cooling water in the cooling water return pipe 4 and output it to the controller 9.

[0058] The controller 9 is used to determine the optimized operating frequency of the cooling tower fan 6 based on the real-time return water temperature value of the cooling water and the preset return water temperature control target value of the cooling water, and is also used to generate a signal to add or remove the cooling tower fan 6 based on the optimized operating frequency and the current number of operating cooling tower fans 6.

[0059] The frequency converter 7 is used to control the speed of the cooling tower fan 6 according to the optimized operating frequency or the output value of the previous operating frequency, and to control the number of operating cooling tower fans 6 to increase or decrease according to the added or reduced signal, so as to adjust the real-time return water temperature value of the cooling water to be dynamically constant within the preset deviation range of the preset cooling water return water temperature control target value.

[0060] Here, the controller 9 acquires the temperature signal collected by the temperature sensor 8, and calculates the optimized operating frequency of the cooling tower fan 6 using a PID algorithm based on the preset target value for cooling water return temperature control. It then outputs a value to the inverter 7 of the cooling tower fan 6, controlling the cooling tower fan 6 to operate at the optimized operating frequency, thereby adjusting the real-time return water temperature in the cooling water return pipe 4 to the preset target value. Furthermore, the controller 9 determines the required number of cooling tower fans 6 to operate based on the optimized operating frequency, and outputs a signal to add or remove cooling tower fans 6 to the inverter 7, thereby controlling the number of cooling tower fans 6 operating at the optimal operating frequency and number of fans to reduce the energy consumption of the cooling tower fans.

[0061] The central air conditioning cooling tower control system of the present invention collects the real-time return water temperature value of the cooling water in the cooling water return pipe 4 through the temperature sensor 8, and the controller 9 determines the optimized operating frequency of the cooling tower fan 6 based on the real-time return water temperature value and the preset cooling water return water temperature control target value, and further determines the required number of cooling tower fans 6 to operate, so as to generate a signal to add or remove cooling tower fans 6. The speed of the cooling tower fan 6 is controlled by the optimized operating frequency, and the relationship between the number of cooling tower fans 6 and the operating frequency is coordinated. The optimized operating frequency of the cooling tower fan can be automatically adjusted according to the real-time return water temperature of the cooling water, and the number of cooling tower fans 6 to operate can be controlled according to the calculated optimized operating frequency of the cooling tower fan 6, which improves the automation level of the entire system, controls the cooling water return water temperature within the target range, and reduces system energy consumption, thereby achieving energy-saving operation of the central air conditioning cooling water system.

[0062] like Figure 2 As shown, in one or more embodiments of the present invention, the controller 9 includes a frequency control module 10 and a start / stop control module 11;

[0063] The frequency control module 10 is used to compare the preset target value of the cooling water return temperature control with the real-time return temperature value of the cooling water, and determine whether the real-time return temperature value of the cooling water is within the preset deviation range of the preset target value of the cooling water return temperature control. If it is, the operating frequency of the inverter 7 is controlled to remain unchanged from the previous operating frequency output value; otherwise, the optimized operating frequency of the cooling tower fan 6 is calculated based on the real-time return temperature value of the cooling water and the preset target value of the cooling water return temperature control, and output to the inverter 7.

[0064] The start / stop control module 11 is used to generate a signal to add or remove cooling tower fans 6 based on the optimized operating frequency and the current number of operating cooling tower fans 6, and output it to the frequency converter 7.

[0065] The frequency control module 10 determines whether the real-time return water temperature exceeds the preset target value for cooling water return water temperature control, thereby determining whether to optimize the operating frequency of the cooling tower fan 6. When the real-time return water temperature exceeds the preset target value for cooling water return water temperature control, the module directly calculates the optimized operating frequency of the cooling tower fan 6 based on the real-time return water temperature and the preset target value for cooling water return water temperature control, thereby adjusting the speed of the cooling tower fan 6. Finally, in conjunction with the start / stop control module 11, the module adjusts the real-time return water temperature to dynamically remain constant within the preset deviation range of the preset target value for cooling water return water temperature control.

[0066] According to the above implementation method, the frequency converter 7 of the cooling tower fan 6 sets the frequency according to the optimized operating frequency of the cooling tower fan 6, adjusts the speed of the cooling tower fan 6, and thus adjusts the return water temperature of the cooling water in the cooling water return pipe 4, maintaining it at the target value of the cooling water return temperature control. Furthermore, the frequency converter 7 of the cooling tower fan 6 controls the number of cooling tower fans 6 in operation according to the increase or decrease signal of the cooling tower fan 6, so that the cooling tower fan 6 operates at the optimal operating frequency and number of units. At this time, the operating energy consumption of the cooling tower fan is minimized, thereby saving energy.

[0067] In one or more embodiments of the present invention, the specific implementation of the start-stop control module 11 generating the add-on signal or reduce-off signal for the cooling tower fan 6 based on the optimized operating frequency and the current number of operating cooling tower fans 6 is as follows:

[0068] When the cooling tower fan 6 is not running at full capacity, the optimized operating frequency range is 25-45Hz.

[0069] When the operating frequency of the cooling tower fan 6 exceeds the preset frequency threshold range for adding a fan, it is determined whether the real-time return water temperature value is greater than the return water temperature deviation threshold for cooling water and continues for a first preset duration. If so, a signal for adding a fan to the cooling tower fan 6 is generated and output to the frequency converter 7.

[0070] When the operating frequency of the cooling tower fan 6 is less than or equal to the preset reduction frequency threshold range, it is determined whether the real-time return water temperature value is less than the cooling water return water temperature deviation threshold and continues for a second preset time. If so, a reduction signal for the cooling tower fan 6 is generated and output to the frequency converter 7.

[0071] When the operating frequency of the cooling tower fan 6 is greater than the preset reduction frequency threshold range but less than the preset increase frequency threshold range, the existing number of cooling tower fans 6 shall be maintained.

[0072] When all cooling tower fans 6 are running, the optimized operating frequency range is 25-50Hz.

[0073] When the operating frequency of the cooling tower fan 6 is less than or equal to the preset reduction frequency threshold range, it is determined whether the real-time return water temperature value is less than the cooling water return water temperature deviation threshold and continues for a second preset time. If so, a reduction signal for the cooling tower fan 6 is generated and output to the frequency converter 7.

[0074] When the operating frequency of the cooling tower fan 6 is greater than the preset reduction frequency threshold range but less than the preset increase frequency threshold range, the existing number of cooling tower fans 6 shall be maintained.

[0075] By comparing the optimized operating frequency with preset reduction and addition frequency thresholds, it can be determined whether the current operating frequency of the cooling tower fan 6 meets the adjustment requirements. When the frequency exceeds the preset addition frequency threshold or is less than the preset reduction frequency threshold and exceeds the corresponding preset temperature deviation threshold for a preset duration, the number of operating cooling tower fans 6 is adjusted accordingly. This coordinates the relationship between the number of operating cooling tower fans 6 and the operating frequency. The optimized operating frequency of the cooling tower fan can be automatically adjusted according to the real-time return water temperature of the cooling water, so as to achieve the goal of dynamically keeping the real-time return water temperature value within the preset deviation range of the preset cooling water return water temperature control target value.

[0076] Specifically, when the cooling tower fans 6 are not all running, the optimized operating frequency range is 25-45Hz, and preferably, the upper limit of the optimized operating frequency is 35Hz.

[0077] When the operating frequency of the cooling tower fan 6 exceeds the preset booster frequency threshold of 35±0.5Hz, it is determined whether the real-time return water temperature value is greater than the cooling water return water temperature deviation threshold for a first preset time of 1 minute. If so, a booster signal for the cooling tower fan 6 is generated and output to the frequency converter 7.

[0078] When the operating frequency of the cooling tower fan 6 is less than or equal to the reduction frequency threshold of 25Hz±0.5Hz, it is determined whether the real-time return water temperature value is less than or equal to the cooling water return water temperature deviation threshold for a second preset time of 2-3 minutes. If so, a reduction signal for the cooling tower fan 6 is generated and output to the frequency converter 7.

[0079] When the operating frequency of the cooling tower fan 6 is greater than the preset reduction frequency threshold range of 25Hz±0.5Hz and less than the preset increase frequency threshold range of 35±0.5Hz, the existing number of cooling tower fans 6 shall be maintained.

[0080] Specifically, when all the cooling tower fans 6 are running, the range of the optimized operating frequency is 25-50Hz. Preferably, when the number of cooling tower fans 6 is 4 or less, the upper limit of the optimized operating frequency is 45Hz; when the number of cooling tower fans 6 is 4 to 8, the upper limit of the optimized operating frequency is 40Hz; and when the number of cooling tower fans 6 is 8 or more, the upper limit of the optimized operating frequency is 35Hz.

[0081] When the operating frequency of the cooling tower fan 6 is less than or equal to the preset reduction frequency threshold range of 25Hz±0.5Hz, it is determined whether the real-time return water temperature value is less than the cooling water return water temperature deviation threshold and continues for a second preset time of 2-3 minutes. If so, a reduction signal for the cooling tower fan 6 is generated and output to the frequency converter 7.

[0082] If the operating frequency of the cooling tower fan 6 is greater than the preset reduction frequency threshold range of 25Hz±0.5Hz and less than the preset increase frequency threshold range of 35±0.5Hz, then the existing number of cooling tower fans 6 shall be maintained.

[0083] According to the above implementation method, the controller 9 calculates the optimal operating frequency of the cooling tower fan based on the real-time return water temperature value of the cooling water and the preset return water temperature control target value. The controller 9 controls the speed of the cooling tower fan 6 through the frequency converter 7 of the cooling tower fan 6, and determines the number of cooling tower fans in operation based on the calculated optimal operating frequency. The controller 9 then controls the number of cooling tower fans 6 to increase or decrease the number of fans in operation through the frequency converter 7 of the cooling tower fan 6, so that the cooling tower fan 6 operates at the optimal operating frequency and number of fans in operation, thereby reducing the energy consumption of the system during operation.

[0084] In embodiments of the present invention, the preset deviation range of the preset target value for cooling water return temperature control is within ±0.2℃ of the target value for cooling water return temperature control.

[0085] Optionally, in one or more embodiments of the present invention, if the number of currently operating cooling tower fans 6 is the maximum or minimum number, the addition or reduction signal will not be executed. For example, if the number of currently operating cooling tower fans 6 is 1, the frequency converter 7 will not execute the reduction signal. If all the cooling tower fans 6 are currently running, the addition signal will not be executed.

[0086] When the number of cooling tower fans 6 currently in operation is the minimum or maximum number, since it is no longer possible to reduce or increase the number of operating cooling tower fans 6, the reduction and addition signals will no longer be executed at this time. This is to ensure the normal operation of the entire cooling tower 1 and avoid downtime.

[0087] It should be noted that, in the embodiments of the present invention, since the central air conditioning cooling tower control system includes at least an automatic mode, a manual mode, and a fault mode, when executing the reduce-fan signal and the add-fan signal, if the currently executing cooling tower fan 6 is in manual mode, it will directly jump to the next fan; if the currently executing cooling tower fan 6 is in a fault mode, it will also directly jump to the next fan.

[0088] Optionally, in one or more embodiments of the present invention, when the real-time return water temperature value of the cooling water is less than a preset limit temperature threshold, it is determined that the real-time return water temperature value of the cooling water is incorrect, and the operating frequency of the inverter 7 is controlled to remain unchanged from the previous output value.

[0089] By setting a preset limit temperature threshold for the real-time return water temperature value, it can be determined that the real-time return water temperature value is incorrect when it is less than the preset limit temperature threshold. At this time, the system will no longer respond based on the incorrect real-time return water temperature value, and the operating frequency of the cooling tower fan 6 will remain unchanged from the previous output value to maintain the stability of the entire system.

[0090] In one or more embodiments of the present invention, the range of the optimized operating frequency is from the upper limit of the frequency to the lower limit of the frequency;

[0091] When the optimized operating frequency is greater than the upper frequency limit, the optimized operating frequency is determined to be equal to the upper frequency limit.

[0092] When the calculated optimized operating frequency is less than the lower frequency limit, the optimized operating frequency is determined to be equal to the lower frequency limit value.

[0093] By setting the upper and lower limits of the optimized operating frequency, a certain safety margin can be left, which can ensure the safety and stability of the entire system.

[0094] Specifically, in an embodiment of the present invention, if all cooling tower fans 6 are turned on, and the real-time return water temperature is still less than the difference between the preset target value of the return water temperature and the preset reduction temperature deviation value (addition temperature deviation value), then the optimized operating frequency is the real-time frequency and the preset reduction frequency deviation value (addition frequency deviation value), which is sent to the frequency converter 7 of the cooling tower fan 6 via an electrical signal. The frequency converter 7 of the cooling tower fan 6 performs frequency conversion adjustment on the speed of the cooling tower fan 6.

[0095] For example, if all cooling tower fans 6 are turned on, and the real-time return water temperature is 25℃, which is still less than the difference of 24℃ between the preset target value of the return water temperature of 25℃ and the preset reduction temperature deviation value (addition temperature deviation value, 1℃), then the optimized operating frequency is the real-time frequency and the preset reduction frequency deviation value (addition frequency deviation value, 1Hz).

[0096] like Figure 3 As shown, the present invention also provides a central air conditioning cooling tower control method, which employs the aforementioned central air conditioning cooling tower control system and includes the following steps:

[0097] S1: 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 return temperature control.

[0098] S2: Collect the real-time return water temperature value of the cooling water in the cooling water return pipe 4, and determine whether the real-time return water temperature value of the cooling water is within the preset deviation range of the preset cooling water return water temperature control target value. If so, control the working frequency of the inverter 7 to maintain the previous working frequency output value unchanged; otherwise, proceed to S3.

[0099] S3: Calculate the optimized operating frequency of the cooling tower fan 6 based on the real-time return water temperature value of the cooling water and the preset return water temperature control target value of the cooling water, and generate a signal to add or remove the cooling tower fan 6 based on the optimized operating frequency and the current number of operating cooling tower fans 6.

[0100] S4: The frequency converter 7 controls the speed of the cooling tower fan 6 according to the optimized working frequency or the output value of the previous working frequency, and controls the number of operating cooling tower fans 6 to increase or decrease according to the add or reduce signal, so as to adjust the real-time return water temperature value of the cooling water to be dynamically constant within the preset deviation range of the preset cooling water return water temperature control target value.

[0101] The central air conditioning cooling tower control method of the present invention collects the real-time return water temperature value of the cooling water in the cooling water return pipe 4 through the temperature sensor 8, and determines the optimized operating frequency of the cooling tower fan 6 based on the real-time return water temperature value and the preset cooling water return water temperature control target value, and further determines the required number of cooling tower fans 6 to generate a signal to add or remove cooling tower fans 6. The speed of the cooling tower fan 6 is controlled by the optimized operating frequency, and the relationship between the number of cooling tower fans 6 and the operating frequency is coordinated. The optimized operating frequency of the cooling tower fan can be automatically adjusted according to the real-time return water temperature of the cooling water, and the number of cooling tower fans 6 can be controlled according to the calculated optimized operating frequency of the cooling tower fan 6. This improves the automation level of the entire system, controls the cooling water return water temperature within the target range, and reduces system energy consumption, thereby achieving energy-saving operation of the central air conditioning cooling water system.

[0102] In one or more embodiments of the present invention, step S4, which generates a signal to add or remove cooling tower fans 6 based on the optimized operating frequency and the current number of operating cooling tower fans 6, specifically includes the following steps:

[0103] When the cooling tower fan 6 is not running at full capacity, the optimized operating frequency range is 25-45Hz.

[0104] When the operating frequency of the cooling tower fan 6 exceeds the preset frequency threshold range for adding a fan, it is determined whether the real-time return water temperature value is greater than the return water temperature deviation threshold for cooling water and continues for a first preset duration. If so, a signal for adding a fan to the cooling tower fan 6 is generated and output to the frequency converter 7.

[0105] When the operating frequency of the cooling tower fan 6 is less than or equal to the preset reduction frequency threshold range, it is determined whether the real-time return water temperature value is less than the cooling water return water temperature deviation threshold and continues for a second preset time. If so, a reduction signal for the cooling tower fan 6 is generated and output to the frequency converter 7.

[0106] When the operating frequency of the cooling tower fan 6 is greater than the preset reduction frequency threshold range but less than the preset increase frequency threshold range, the existing number of cooling tower fans 6 shall be maintained.

[0107] When all cooling tower fans 6 are running, the optimized operating frequency range is 25-50Hz.

[0108] When the operating frequency of the cooling tower fan 6 is less than or equal to the preset reduction frequency threshold range, it is determined whether the real-time return water temperature value is less than the cooling water return water temperature deviation threshold and continues for a second preset time. If so, a reduction signal for the cooling tower fan 6 is generated and output to the frequency converter 7.

[0109] When the operating frequency of the cooling tower fan 6 is greater than the preset reduction frequency threshold range but less than the preset increase frequency threshold range, the existing number of cooling tower fans 6 shall be maintained.

[0110] By comparing the optimized operating frequency with preset reduction and addition frequency thresholds, it can be determined whether the current operating frequency of the cooling tower fan 6 meets the adjustment requirements. When the frequency exceeds the preset addition frequency threshold or is less than the preset reduction frequency threshold and exceeds the corresponding preset temperature deviation threshold for a preset duration, the number of operating cooling tower fans 6 is adjusted accordingly. This coordinates the relationship between the number of operating cooling tower fans 6 and the operating frequency. The optimized operating frequency of the cooling tower fan can be automatically adjusted according to the real-time return water temperature of the cooling water, so as to achieve the goal of dynamically keeping the real-time return water temperature value within the preset deviation range of the preset cooling water return water temperature control target value.

[0111] The central air conditioning cooling tower control method of this invention will be described below from the perspectives of controlling the operating frequency of the cooling tower fan 6 and controlling the number of cooling tower fans 6 in operation.

[0112] a. Control of the operating frequency of cooling tower fan (6):

[0113] S1 a: Set the dead zone range △S for the target value of the cooling water return temperature control (default value is 0.2℃);

[0114] S2a: The frequency control module 10 in the controller determines whether the real-time return water temperature value of the cooling water is within the deviation range (Tclre) of the preset cooling water return water temperature control target value based on the real-time return water temperature value detected by the temperature sensor 8. set -ΔS,Tclre set If the value is within +ΔS), the operating frequency remains unchanged from the previous output value; otherwise, the frequency control module 10 recalculates the optimized operating frequency using a PID algorithm; if the real-time return water temperature value of the cooling water detected by the temperature sensor 8 is less than 0℃, it indicates that the feedback value is incorrect, and the optimized operating frequency remains unchanged from the previous output value.

[0115] S3a: The frequency converter 7 of the cooling tower fan 6 adjusts the speed of the cooling tower fan 6 according to the optimized operating frequency, so as to adjust the air volume of the cooling tower fan 6, thereby controlling the return water temperature of the cooling water and keeping it within the deviation range of the preset target value of the return water temperature control.

[0116] When the detected return water temperature is greater than the target value for cooling water return temperature control, the PID algorithm calculates a larger optimized operating frequency based on the deviation value, and then sends the optimized operating frequency to the inverter 7 of the cooling tower fan 6 to increase the speed of the cooling tower fan 6, thereby reducing the real-time return water temperature value of the cooling water; when the detected return water temperature is less than the target value for cooling water return temperature control, the PID algorithm calculates a smaller optimized operating frequency based on the deviation value, and then sends the optimized operating frequency signal to the inverter 7 of the cooling tower fan 6 to decrease the speed of the cooling tower fan 6, thereby increasing the real-time return water temperature value of the cooling water.

[0117] During the control process, the optimized operating frequency variation range is set in the frequency optimization algorithm. Generally, the optimized operating frequency variation range is 30Hz to 48Hz. That is, during the frequency conversion process, if the optimized operating frequency drops below 30Hz, the output is 30Hz and the cooling tower fan 6 runs at 30Hz; if the optimized operating frequency rises above 48Hz, the output is 48Hz and the cooling tower fan 6 runs at 48Hz.

[0118] b. Control of the number of working units of cooling tower fan 6:

[0119] S1 b: The central air conditioning system is turned on, all cooling tower fans 6 are fully turned on and the operating frequency of cooling tower fans 6 is initialized to 30Hz;

[0120] S2b: The frequency control module 10 in the controller 9 calculates the difference between the preset cooling water return temperature control target value and the real-time cooling water return temperature value based on the real-time cooling water return temperature value detected and collected by the temperature sensor 8.

[0121] S3b: If the difference between the preset target value for cooling water return temperature control and the real-time return temperature value is less than -1℃, then determine whether the real-time operating frequency of the cooling tower fan 6 is less than 31Hz and the duration reaches 30 minutes; if so, then obtain the number of cooling tower fans 6 in operation. If multiple cooling tower fans 6 are operating, then reduce the number of cooling tower fans by one in order of their numbers. If only one cooling tower fan 6 is operating, then no adjustment is made; if the difference between the preset target value for cooling water return temperature control and the real-time return temperature value is not less than -1℃, the real-time operating frequency of the cooling tower fan 6 is not less than 31Hz and / or the duration does not reach 30 minutes, then no adjustment is made.

[0122] S4b: If the difference between the preset target value for cooling water return temperature control and the real-time return temperature value is greater than 1℃, then determine whether the real-time operating frequency of the cooling tower fan 6 is greater than 40Hz and the duration reaches 10min; if so, then obtain the number of cooling tower fans 6 in operation. If any cooling tower fans 6 are not turned on, then add one cooling tower fan 6 in numerical order, and its operating frequency is synchronized with the operating frequency of the already turned-on cooling tower fans 6. If all cooling tower fans 6 are turned on, then increment the real-time frequency of all cooling tower fans 6 by 1 and send it to the frequency converter 7 of the cooling tower fan 6 via an electrical signal. The frequency converter 7 of the cooling tower fan 6 adjusts the speed of the cooling tower fan 6 by frequency conversion. If the difference between the preset target value for cooling water return temperature control and the real-time return temperature value is not greater than 1℃, the real-time operating frequency of the cooling tower fan 6 is not greater than 40Hz and / or the duration does not reach 10min, then no adjustment is made.

[0123] S5b: If the difference between the preset target value for cooling water return temperature control and the real-time value for cooling water return temperature is greater than -1℃ and less than 1℃, no adjustment will be made.

[0124] Through the above control system and control method, in control method a, the cooling water return temperature control of cooling tower 1 is based on the preset cooling water return temperature control target value and the real-time cooling water return temperature value of the system to control the working frequency of cooling tower fan 6, so that cooling tower fan 6 operates in an optimized working frequency state; in control method b, the number of cooling towers 1 in operation is controlled according to the difference between the preset cooling water return temperature control target value and the real-time cooling water return temperature value of the system, which saves energy consumption of cooling towers while meeting the user's cooling capacity requirements, realizes energy-saving operation of the system, effectively improves the intelligence level of cooling water system operation, and improves indoor thermal comfort.

[0125] The present invention also provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores computer instructions, which are used to cause a processor to execute the central air conditioning cooling tower control method.

[0126] The present invention also provides a central air conditioning cooling tower control device, the central air conditioning cooling tower control device comprising:

[0127] At least one processor and a storage medium, wherein the memory is communicatively connected to the processor;

[0128] The storage medium stores a computer program that can be executed by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to execute the central air conditioning cooling tower control method.

[0129] 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 central air conditioning cooling tower control system, characterized in that: The system includes a cooling water circuit formed by a cooling tower (1), a condenser (2), and a cooling water pump (3) connected in sequence, and a controller (9). The cooling tower (1) and the condenser (2) are connected by a cooling water supply pipe (5). The cooling tower (1) and the cooling water pump (3) and the cooling water pump (3) and the condenser (2) are connected by cooling water return pipes (4). A temperature sensor (8) is installed on the cooling water return pipe (4). A cooling tower fan (6) is installed on the cooling tower (1). The cooling tower fan (6) is equipped with a frequency converter (7). The frequency converter (7) and the temperature sensor (8) are electrically connected to the controller (9). The temperature sensor (8) is used to collect the real-time return water temperature value of the cooling water in the cooling water return pipe (4) and output it to the controller (9). The controller (9) is used to determine the optimized operating frequency of the cooling tower fan (6) based on the real-time return water temperature value of the cooling water and the preset return water temperature control target value of the cooling water, and is also used to generate a signal to add or remove the cooling tower fan (6) based on the optimized operating frequency and the current number of the cooling tower fan (6) in operation. The inverter (7) is used to control the speed of the cooling tower fan (6) according to the output value of the optimized working frequency or the previous working frequency, and to control the number of operating cooling tower fans (6) to increase or decrease according to the addition signal or reduction signal, so as to adjust the real-time return water temperature value of the cooling water to be dynamically constant within the preset deviation range of the preset cooling water return water temperature control target value. The controller (9) includes a start / stop control module (11); The start-stop control module (11) is used to generate a signal to add or remove the cooling tower fan (6) based on the optimized operating frequency and the current number of operating cooling tower fans (6), and output it to the frequency converter (7). The specific implementation of the start / stop control module (11) generating the add or remove signal for the cooling tower fan (6) based on the optimized operating frequency and the current number of operating cooling tower fans (6) is as follows: When the cooling tower fan (6) is not running at full capacity, the optimized operating frequency range is 25-45Hz: When the operating frequency of the cooling tower fan (6) exceeds the preset addition frequency threshold, it is determined whether the real-time return water temperature value is greater than the return water temperature deviation threshold of the cooling water and continues for a first preset time. If so, an addition signal for the cooling tower fan (6) is generated and output to the frequency converter (7). When the operating frequency of the cooling tower fan (6) is less than or equal to the preset reduction frequency threshold, it is determined whether the real-time return water temperature value is less than the return water temperature deviation threshold of the cooling water and continues for a second preset time. If so, a reduction signal for the cooling tower fan (6) is generated and output to the frequency converter (7). When the operating frequency of the cooling tower fan (6) is greater than the preset reduction frequency threshold and less than the preset increase frequency threshold range, the existing number of cooling tower fans (6) shall be maintained. When all cooling tower fans (6) are running, the optimized operating frequency range is 25-50Hz: When the operating frequency of the cooling tower fan (6) is less than or equal to the preset reduction frequency threshold, it is determined whether the real-time return water temperature value is less than the return water temperature deviation threshold of the cooling water and continues for a second preset time. If so, a reduction signal for the cooling tower fan (6) is generated and output to the frequency converter (7). When the operating frequency of the cooling tower fan (6) is greater than the preset reduction frequency threshold and less than the preset increase frequency threshold, the existing number of cooling tower fans (6) is maintained.

2. The central air conditioning cooling tower control system according to claim 1, characterized in that: The controller (9) also includes a frequency control module (10); The frequency control module (10) is used to compare the preset target value of the cooling water return temperature control with the real-time return temperature value of the cooling water, and determine whether the real-time return temperature value of the cooling water is within the preset deviation range of the preset target value of the cooling water return temperature control. If so, the operating frequency of the inverter (7) is controlled to remain unchanged from the previous operating frequency output value. Otherwise, the optimized operating frequency of the cooling tower fan (6) is calculated based on the real-time return temperature value of the cooling water and the preset target value of the cooling water return temperature control, and output to the inverter (7).

3. The central air conditioning cooling tower control system according to claim 2, characterized in that: When the real-time return water temperature of the cooling water is less than the preset limit temperature threshold, the real-time return water temperature of the cooling water is determined to be an error, and the operating frequency of the inverter (7) is controlled to remain unchanged from the previous output value.

4. The central air conditioning cooling tower control system according to claim 2, characterized in that: The range of the optimized operating frequency is from the upper frequency limit to the lower frequency limit; When the optimized operating frequency is greater than the upper frequency limit, the optimized operating frequency is determined to be equal to the upper frequency limit. When the calculated optimized operating frequency is less than the lower frequency limit, the optimized operating frequency is determined to be equal to the lower frequency limit value.

5. A method for controlling a central air conditioning cooling tower, characterized in that: The central air conditioning cooling tower control system according to any one of claims 1-4 includes the following steps: S1: Turn on the central air conditioning cooling tower control system and initialize the working frequency of the cooling tower fan (6) and the target value of the return water temperature of the cooling water; S2: Collect the real-time return water temperature value of the cooling water in the cooling water return pipe (4), and determine whether the real-time return water temperature value of the cooling water is within the preset deviation range of the preset cooling water return water temperature control target value. If so, control the working frequency of the inverter (7) to maintain the previous working frequency output value unchanged; otherwise, proceed to S3. S3: Calculate the optimized operating frequency of the cooling tower fan (6) based on the real-time return water temperature value of the cooling water and the preset return water temperature control target value of the cooling water, and generate a signal to add or remove the cooling tower fan (6) based on the optimized operating frequency and the current number of the cooling tower fan (6) in operation. S4: The inverter (7) controls the speed of the cooling tower fan (6) according to the optimized working frequency or the output value of the previous working frequency, and controls the number of operating cooling tower fans (6) to increase or decrease according to the addition signal or reduction signal, so as to adjust the real-time return water temperature value of the cooling water to be dynamically constant within the preset deviation range of the preset cooling water return water temperature control target value. In step S4, generating a signal to add or remove cooling tower fans (6) based on the optimized operating frequency and the current number of operating cooling tower fans (6) specifically includes the following steps: When the cooling tower fan (6) is not running at full capacity, the optimized operating frequency range is 25-45Hz: When the operating frequency of the cooling tower fan (6) exceeds the preset addition frequency threshold, it is determined whether the real-time return water temperature value is greater than the return water temperature deviation threshold of the cooling water and continues for a first preset time. If so, an addition signal for the cooling tower fan (6) is generated and output to the frequency converter (7). When the operating frequency of the cooling tower fan (6) is less than or equal to the preset reduction frequency threshold, it is determined whether the real-time return water temperature value is less than the return water temperature deviation threshold of the cooling water and continues for a second preset time. If so, a reduction signal for the cooling tower fan (6) is generated and output to the frequency converter (7). When the operating frequency of the cooling tower fan (6) is greater than the preset reduction frequency threshold and less than the preset increase frequency threshold range, the existing number of cooling tower fans (6) shall be maintained. When all cooling tower fans (6) are running, the optimized operating frequency range is 25-50Hz: When the operating frequency of the cooling tower fan (6) is less than or equal to the preset reduction frequency threshold, it is determined whether the real-time return water temperature value is less than the return water temperature deviation threshold of the cooling water and continues for a second preset time. If so, a reduction signal for the cooling tower fan (6) is generated and output to the frequency converter (7). When the operating frequency of the cooling tower fan (6) is greater than the preset reduction frequency threshold and less than the preset increase frequency threshold, the existing number of cooling tower fans (6) is maintained.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that are used to cause a processor to execute the central air conditioning cooling tower control method of claim 5.

7. A central air conditioning cooling tower control device, characterized in that, The central air conditioning cooling tower control equipment includes: At least one processor and a memory, wherein the memory is communicatively connected to the processor; The memory stores a computer program that can be executed by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to perform the central air conditioning cooling tower control method according to claim 5.

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