A central air conditioning system and its control method

Abstract

This application provides a central air conditioning system and its control method, relating to the field of air conditioning technology. The central air conditioning system includes: a cooling tower; a chiller unit; a first temperature sensor; a humidity sensor; and a controller configured to: acquire the current operating condition of the cooling tower and multiple control strategies under the current operating condition; determine the design operating power of the cooling tower corresponding to each control strategy under the current operating condition based on the current operating condition, the multiple control strategies, and a first energy consumption model; determine a target control strategy based on the design operating power of the cooling tower corresponding to each control strategy, the target control strategy being the control strategy with the lowest corresponding design operating power among all control strategies; determine a target operating frequency of the cooling tower based on the design operating power corresponding to the target control strategy and a second energy consumption model; and control the cooling tower to operate according to the target control strategy and the target operating frequency.

Description

Technical Field

[0001] This application relates to the field of air conditioning technology, and in particular to a central air conditioning system and its control method. Background Technology

[0002] With the development of society and economy, people's living standards are getting higher and higher, and the application of central air conditioning systems in daily life is becoming more and more widespread.

[0003] In central air conditioning systems, the majority of energy consumption is concentrated in the chiller units, and related technologies often focus on optimizing these units to achieve energy savings. However, under full-load operation, the cooling towers in the refrigeration plant account for 12%-15% of the total energy consumption. Therefore, the energy-saving potential of the cooling towers in large-scale central air conditioning systems should not be underestimated.

[0004] Therefore, how to optimize and control the energy efficiency of cooling towers in refrigeration plants is an urgent problem to be solved. Summary of the Invention

[0005] This application provides a central air conditioning system and its control method, which calculates the design operating power of the cooling tower under various control strategies under the current operating conditions based on a first energy consumption model. Then, based on the minimum design operating power under the current operating conditions and a second energy consumption model, a target operating frequency and a target control strategy are determined. Furthermore, controlling the cooling tower to operate according to the aforementioned target operating frequency and target control strategy minimizes the cooling tower's operating energy consumption under the current operating conditions, thereby achieving energy saving.

[0006] To achieve the above objectives, the embodiments of this application adopt the following technical solutions:

[0007] In a first aspect, a central air conditioning system is provided, the central air conditioning system comprising:

[0008] Cooling towers are used to assist in cooling water temperature reduction;

[0009] A chiller unit, which includes a condenser; cooling water circulates in a loop consisting of a cooling tower and a condenser.

[0010] The first temperature sensor is used to detect the outdoor dry-bulb temperature.

[0011] Humidity sensor, used to detect outdoor relative humidity;

[0012] The controller is electrically connected to the cooling tower, chiller unit, first temperature sensor, and humidity sensor. The controller is configured as follows:

[0013] The current operating conditions of the cooling tower and multiple control strategies under the current operating conditions are obtained. The current operating conditions are determined by the current outdoor dry-bulb temperature and the current outdoor relative humidity. The control strategies include the design cooling water temperature difference, the design cooling water flow rate, and the design approximation.

[0014] Based on the current operating conditions, multiple control strategies, and the first energy consumption model, the design operating power of the cooling tower corresponding to each control strategy under the current operating conditions is determined; the first energy consumption model is used to characterize the relationship between the design operating power of the cooling tower and the control strategy.

[0015] Based on the design operating power of the cooling tower corresponding to each group of control strategies, the target control strategy is determined. The target control strategy is the control strategy with the lowest design operating power among all the control strategies.

[0016] The target operating frequency of the cooling tower is determined based on the minimum design operating power and the second energy consumption model; the second energy consumption model is used to characterize the relationship between the design operating power and the target operating frequency of the cooling tower.

[0017] The cooling tower is controlled to operate according to the target control strategy and target operating frequency.

[0018] The technical solution provided in this application provides at least the following beneficial effects: Since the energy consumption of a cooling tower is related to its operating conditions and control strategies, changes in outdoor dry-bulb temperature and relative humidity, or changes in the cooling water temperature difference, cooling water flow rate, and approximation degree, can alter the cooling tower's energy consumption. Therefore, this application calculates the design operating power of the cooling tower under various control strategies based on a first energy consumption model. These various design operating powers reflect the energy consumption corresponding to each cooling tower control strategy under the current operating conditions. Since the control strategy corresponding to the minimum design operating power has the lowest energy consumption, it is used as the target control strategy. Furthermore, the target operating power is determined based on the minimum design operating power and a second energy consumption model. Thus, controlling the cooling tower's operation according to the target control strategy and target operating frequency minimizes the cooling tower's energy consumption under the current operating conditions, thereby achieving energy savings.

[0019] In some embodiments, the central air conditioning system further includes: a second temperature sensor for detecting a first temperature, the first temperature being the temperature at which cooling water enters the cooling tower; a third temperature sensor for detecting a second temperature, the second temperature being the temperature at which cooling water flows out of the cooling tower; and a flow meter for detecting the flow rate of the cooling water; the second temperature sensor, the third temperature sensor, and the flow meter are electrically connected to the controller; the first energy consumption model is obtained by the controller performing the following steps: acquiring historical data information of the cooling tower under multiple historical operating conditions within a preset time period, and historical operating power, historical operating frequency, and rated operating power corresponding to the historical data information; the historical data information under each historical operating condition includes historical wet-bulb temperature, historical control strategy, and preset wet-bulb temperature corresponding to the historical operating condition. The system includes preset cooling water temperature difference, preset cooling water flow rate, and preset approximation degree. The historical control strategy includes historical cooling water temperature difference, historical cooling water flow rate, and historical approximation degree. The historical wet-bulb temperature is determined by the historical outdoor dry-bulb temperature and historical outdoor relative humidity under historical operating conditions. Historical data from multiple historical operating conditions are removed, including those with historical operating frequencies lower than a first preset frequency, historical operating frequencies higher than a second preset frequency, and historical operating power greater than a first preset power but less than a second preset power, to obtain the first data information. The first data information is then dimensionlessly processed to obtain the second data information. Finally, the second data information is fitted and regressed using the least squares method to obtain the first energy consumption model.

[0020] As can be seen from the above embodiments, the operating power of the cooling tower is related to the wet-bulb temperature, cooling water temperature difference, cooling water flow rate, and approximation degree. Therefore, the historical wet-bulb temperature, historical cooling water temperature difference, historical cooling water flow rate, historical approximation degree, historical operating frequency, as well as the preset wet-bulb temperature, preset cooling water temperature difference, preset cooling water flow rate, preset approximation degree, and rated operating frequency within a preset time period can be fitted and regressed using the least squares method to obtain the first energy consumption model. In this way, based on the first energy consumption model, the data under the current operating conditions, and various design control strategies, the design operating power corresponding to each control strategy can be derived. Furthermore, since the cooling tower may experience malfunctions during operation, leading to anomalies in its historical operating power or historical operating frequency data, removing the historical data corresponding to the abnormal historical operating frequencies and power can eliminate interference factors in the historical data, thereby improving the accuracy of the first energy consumption model. In addition, by performing fitting and regression processing on the second data information using the least squares method, an approximate function can be determined based on the fitted curve, thus obtaining the first energy consumption model.

[0021] In some embodiments, the first energy consumption model described above includes:

[0022]

[0023] Where P represents historical operating power; P e ΔT represents the rated operating power; ΔT represents the historical cooling water temperature difference; ΔT e Represents the preset cooling water temperature difference; T app Represents the degree of historical proximity; T app,e T represents the preset approximation degree; wb Represents historical wet-bulb temperature; T wb,e Represents the preset wet-bulb temperature; m cw Represents historical cooling water flow rate; m cw,e represents the preset cooling water flow rate; a, b, c, d, e, r, g, h, i, j, k, l, m, n, o represent the coefficients of the first energy consumption model.

[0024] In some embodiments, the second energy consumption model is obtained by the controller by performing the following steps: obtaining the rated operating frequency corresponding to the historical operating frequency corresponding to the second data information within a preset time period; performing fitting regression processing on the historical operating power, historical operating power, rated operating power, and rated operating frequency corresponding to the second data information using the least squares method to obtain the second energy consumption model.

[0025] As can be seen from the above embodiments, by performing fitting regression processing on the historical operating power, rated operating power, and rated operating frequency in the second data information using the least squares method, an approximate function can be determined based on the fitted curve, thereby obtaining the second energy consumption model.

[0026] In some embodiments, the second energy consumption model described above includes:

[0027]

[0028] Where P represents historical operating power; P e f represents the rated operating power; f represents the target operating frequency of the cooling tower; f e A represents the rated operating frequency of the cooling tower; A, B, and C represent the coefficients of the second model.

[0029] Secondly, embodiments of this application provide a control method for a central air conditioning system, the central air conditioning system comprising:

[0030] Cooling towers are used to assist in cooling water temperature reduction;

[0031] A chiller unit, which includes a condenser; cooling water circulates in a loop consisting of a cooling tower and a condenser.

[0032] The first temperature sensor is used to detect the outdoor dry-bulb temperature.

[0033] Humidity sensor, used to detect outdoor relative humidity;

[0034] The method includes:

[0035] The current operating conditions of the cooling tower and multiple control strategies under the current operating conditions are obtained. The current operating conditions are determined by the current outdoor dry-bulb temperature and the current outdoor relative humidity. The control strategies include the design cooling water temperature difference, the design cooling water flow rate, and the design approximation.

[0036] Based on the current operating conditions, multiple control strategies, and the first energy consumption model, the design operating power of the cooling tower corresponding to each control strategy under the current operating conditions is determined; the first energy consumption model is used to characterize the relationship between the design operating power of the cooling tower and the control strategy.

[0037] Based on the design operating power of the cooling tower corresponding to each group of control strategies, the target control strategy is determined. The target control strategy is the control strategy with the lowest design operating power among all the control strategies.

[0038] Based on the design operating power and the second energy consumption model corresponding to the target control strategy, the target operating frequency of the cooling tower is determined; the second energy consumption model is used to characterize the relationship between the design operating power and the target operating frequency of the cooling tower.

[0039] The cooling tower is controlled to operate according to the target control strategy and target operating frequency.

[0040] Thirdly, embodiments of this application provide a controller, including: one or more processors; one or more memories; wherein the one or more memories are used to store computer program code, the computer program code including computer instructions, and when the one or more processors execute the computer instructions, the controller executes the control method provided in the second aspect.

[0041] Fourthly, embodiments of this application provide a computer-readable storage medium including computer instructions that, when controlled on a computer, cause the computer to perform the methods provided in the second aspect and possible implementations.

[0042] Fifthly, embodiments of the present invention provide a computer program product that can be directly loaded into a memory and contains software code. After being loaded and executed by a computer, the computer program product can implement the methods provided in the second aspect and possible implementations.

[0043] It should be noted that the aforementioned computer instructions may be stored, in whole or in part, on a computer-readable storage medium. This computer-readable storage medium may be packaged together with the controller's processor, or it may be packaged separately from the controller's processor; this application does not impose any limitations on this.

[0044] The beneficial effects described in aspects two through five of this application can be referred to the analysis of the beneficial effects of aspect one, and will not be repeated here. Attached Figure Description

[0045] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0046] Figure 1 This application provides a schematic diagram of the structure of a central air conditioning system according to an embodiment of the present application.

[0047] Figure 2 This is a schematic diagram of the structure of a chiller provided in an embodiment of this application;

[0048] Figure 3 This is a schematic diagram of another chiller unit provided in an embodiment of this application;

[0049] Figure 4 A schematic diagram of the hardware structure of a controller provided in an embodiment of this application;

[0050] Figure 5 A flowchart illustrating a control method for a central air conditioning system provided in an embodiment of this application;

[0051] Figure 6 This is a schematic diagram of an experimental data fitting result provided in an embodiment of this application;

[0052] Figure 7 This is a schematic diagram of another experimental data fitting result provided in an embodiment of this application;

[0053] Figure 8 This is a schematic diagram of another experimental data fitting result provided in an embodiment of this application;

[0054] Figure 9 This is a schematic diagram of another experimental data fitting result provided in an embodiment of this application;

[0055] Figure 10 This is a schematic diagram of the hardware structure of another controller provided in an embodiment of this application. Detailed Implementation

[0056] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0057] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0058] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0059] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0060] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, when describing pipelines, the terms "connected" and "connected" as used in this application have the meaning of establishing electrical conductivity. The specific meaning needs to be understood in conjunction with the context.

[0061] The terms “comprising” and “having”, and any variations thereof, used in the description of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include other steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0062] Furthermore, in the embodiments of this application, the words "exemplary" or "for example" are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Specifically, the use of the words "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0063] As described in the background section, related technologies often focus on achieving energy savings through the optimization of chiller units. However, cooling towers account for 12%-15% of the total electricity consumption of a central air conditioning system under full load operation. In large-scale central air conditioning systems, the energy-saving potential of the cooling tower section should not be underestimated.

[0064] To address the aforementioned problems, this application provides a central air conditioning system and its control method. Based on historical operating data and preset data of the central air conditioning system under different operating conditions, a first energy consumption model and a second energy consumption model are established. The first energy consumption model yields multiple design operating powers of the cooling tower under the current operating conditions. Based on the minimum design operating power under the current operating conditions, the second energy consumption model determines the target operating frequency for that current operating condition. This allows the cooling tower to be controlled to operate at the target operating frequency, thereby reducing energy consumption.

[0065] It should be noted that in the embodiments of this application, the operating power of the cooling tower refers to the operating power of the cooling tower fan in the cooling tower, and the operating frequency of the cooling tower refers to the operating frequency of the cooling tower fan in the cooling tower, which will not be repeated below.

[0066] To further describe the technical solutions of the embodiments of this application, as follows: Figure 1 The diagram shown is a structural diagram of a central air conditioning system provided in an embodiment of this application.

[0067] Reference Figure 1 The central air conditioning system 1 includes: a chiller unit 101, a water distributor 102, a water collector 103, a chilled water pump 104, a cooling water pump 105, a cooling tower 106, a first temperature sensor 107, a second temperature sensor 108, a third temperature sensor 109, a humidity sensor 110, a flow meter 111, and a controller 40 (the first temperature sensor 107, the second temperature sensor 108, the third temperature sensor 109, the humidity sensor 110, the flow meter 111, and the controller 40 are located in...). Figure 1 (Not shown in the image). The chiller, water distributor, water collector, and chilled water pump connected in sequence form a chilled water circuit; the chiller, cooling water pump, and cooling tower connected in sequence form a cooling water circuit.

[0068] In some embodiments, the chiller unit 101 is used to cool the flowing chilled water.

[0069] Optionally, chiller unit 101 may include multiple chiller units.

[0070] In some embodiments, such as Figure 2As shown, the chiller unit includes a compressor 1011, a condenser 1012, an evaporator 1013, and a throttling device 1014. The compressor 1011, condenser 1012, evaporator 1013, and throttling device 1014 are sequentially connected to form a refrigerant circulation loop. It should be noted that in this embodiment, the sequential connection only indicates the order of connection between the components; other components may also be included between them. For example, a shut-off valve can be installed on the pipeline between the compressor 1011 and the condenser 1012.

[0071] During refrigeration, such as Figure 3 As shown, compressor 1011 compresses low-temperature, low-pressure refrigerant gas into high-temperature, high-pressure refrigerant gas and discharges it into condenser 1012. In condenser 1012, the high-temperature, high-pressure refrigerant gas exchanges heat with the outdoor airflow, releasing heat. This released heat is carried by the airflow into the outdoor ambient air, causing the refrigerant to undergo a phase change and condense into a liquid or gas-liquid two-phase refrigerant. The refrigerant flows out of condenser 1012 and enters throttling device 1014 to cool and depressurize, becoming a low-temperature, low-pressure refrigerant. This low-temperature, low-pressure refrigerant enters evaporator 1013, where it absorbs heat from the refrigerant in evaporator 1013, lowering the temperature of the refrigerant in evaporator 1013 and achieving a cooling effect. The refrigerant then undergoes a phase change and evaporates into low-temperature, low-pressure refrigerant gas, flowing back into compressor 1011, thus achieving refrigerant recycling.

[0072] In some embodiments, the distributor 102 is used to distribute chilled water flow to each branch to achieve pressure equalization.

[0073] For example, the inlet end of the water distributor 102 is connected to the outlet end of the chiller unit 101, and the outlet end of the water distributor 102 is connected to the chilled equipment, which is used to distribute the chilled water flow to each branch to achieve pressure equalization.

[0074] In some embodiments, the water collector 103 is used to collect the chilled water from each branch.

[0075] Optionally, the inlet end of the water collector 103 is connected to the cooling equipment, and the outlet end of the water collector 103 is connected to the chilled water pump through a chilled water pump valve.

[0076] For example, the water distributor 102 and the water collector 103 are connected to the cooling equipment via connecting pipes. Chilled water flows from the outlet end of the water distributor 102 through the connecting pipes through the cooling equipment, and then enters the water collector 103 from the inlet end of the water collector 103 through the connecting pipes.

[0077] In some embodiments, the chilled water pump 104 is used to circulate chilled water, allowing the chilled water to exchange heat with the indoor air to reduce the indoor air temperature, thereby achieving a cooling effect.

[0078] Optionally, the first end of the chilled water pump 104 is connected to the inlet end of the chiller unit 101, and the second end of the chilled water pump 104 is connected to the outlet end of the water collector 103.

[0079] Optionally, the chilled water pump 104 also includes a chilled water pump valve, which is used to control the flow rate of chilled water in the pipeline by controlling the opening degree of the chilled water pump valve.

[0080] In some embodiments, the cooling water pump 105 is used to circulate cooling water. After the chilled water removes indoor heat, the heat is transferred to the cooling water through the chiller unit 101. The cooling water pump pressurizes the heated cooling water into the cooling tower, allowing the heated cooling water to exchange heat with the atmosphere. Furthermore, after the cooling water cools down, it is sent back to the condenser 1012 in the chiller unit to continue heat exchange.

[0081] Optionally, the first outdoor end of the cooling water pump 105 is connected to the outlet end of the chiller unit 101, and the second end of the cooling water pump 105 is connected to the first end of the cooling tower 106.

[0082] Optionally, the cooling water pump 105 also includes a cooling water pump valve, which is used to control the opening degree of the cooling water pump valve to control the flow rate of cooling water in the pipeline.

[0083] In some embodiments, the cooling tower 106 is used to disperse heat in the cooling water, dissipate heat through airflow to lower the temperature of the cooling water, and then recycle the cooling water.

[0084] Optionally, the second end of the cooling tower 106 is connected to the inlet end of the chiller unit 101. The cooling tower 106 includes at least one cooling tower fan, which is used to circulate the air around it to accelerate the reduction of the cooling water temperature. The number of cooling towers 106 can be one or more, and this embodiment does not limit this.

[0085] In some embodiments, the first temperature sensor 107 is used to detect the outdoor dry-bulb temperature.

[0086] Optionally, the first temperature sensor 107 is located near the cooling tower 106 and is in contact with outdoor air.

[0087] In some embodiments, a second temperature sensor 108 is used to detect the temperature of cooling water entering the cooling tower 106.

[0088] Optionally, a second temperature sensor 108 is located at the first end of the cooling tower 106.

[0089] In some embodiments, it is used to detect the temperature of cooling water flowing out of cooling tower 106.

[0090] Optionally, a third temperature sensor 109 is located at the second end of the cooling tower 106.

[0091] In some embodiments, the humidity sensor 110 is used to detect the outdoor relative humidity.

[0092] Optionally, the humidity sensor 110 is located near the cooling tower 106 and is in contact with outdoor air.

[0093] In some embodiments, the flow meter 111 is used to detect the flow rate of cooling water.

[0094] Optionally, the flow meter 111 is located at the second end of the cooling tower.

[0095] In some embodiments, such as Figure 4 As shown, the controller 40 is electrically connected to the chiller unit 101, chilled water pump 104, cooling water pump 105, cooling tower 106, first temperature sensor 107, second temperature sensor 108, third temperature sensor 109, humidity sensor 110, and flow meter 111. It is used to generate operation control signals based on instruction operation codes and timing signals, instructing the central air conditioning system 1 to execute control commands. For example, the controller 40 can acquire the outdoor dry-bulb temperature detected by the first temperature sensor 107, the first temperature detected by the second temperature sensor 108, the second temperature detected by the third temperature sensor 109, the outdoor relative humidity detected by the humidity sensor 110, and the cooling water flow rate detected by the flow meter 111.

[0096] For example, the controller 40 may be a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The controller 40 may also be other devices with processing functions, such as circuits, devices, or software modules, and the embodiments of this application do not impose any limitations on this.

[0097] In some embodiments, the controller 40 can be a microcontroller unit (MCU). An MCU, also known as a single-chip microcomputer, is a chip-level computer that integrates a central processing unit (CPU) with appropriately reduced frequency and specifications, along with peripheral interfaces such as memory, timer, USB, A / D converter, UART, PLC, DMA, and even LCD driver circuitry, all onto a single chip. This allows for different combinations of control for various applications.

[0098] Furthermore, the controller 40 can be used to control the operation of various components in the central air conditioning system 1, so that the various components of the central air conditioning system 1 operate to achieve the predetermined functions of the central air conditioning system 1. It is understood that the structure illustrated in the embodiments of the present invention does not constitute a specific limitation on the central air conditioning system. In other embodiments of this application, the central air conditioning system may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0099] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0100] like Figure 5 As shown in the figure, this application provides a control method for a central air conditioning system, applied to the controller of the central air conditioning system. The method includes the following steps:

[0101] S101. Obtain the current operating condition of the cooling tower and multiple control strategies under the current operating condition.

[0102] The current operating condition is determined by the current outdoor dry-bulb temperature and the current outdoor relative humidity. The control strategies include the design cooling water temperature difference, the design cooling water flow rate, and the design approximation degree. Under the current operating condition, multiple control strategies can be obtained by combining different design cooling water temperature differences, design cooling water flow rates, and design approximation degrees.

[0103] S102. Based on the current operating conditions, multiple control strategies, and the first energy consumption model, determine the design operating power of the cooling tower corresponding to each control strategy under the current operating conditions.

[0104] The first energy consumption model is used to characterize the relationship between the design operating power of the cooling tower and the control strategy.

[0105] For example, under the current operating condition, the current wet-bulb temperature can be determined based on the current outdoor dry-bulb temperature detected by the first temperature sensor and the current outdoor relative humidity detected by the humidity sensor. The current wet-bulb temperature, along with the multiple sets of design cooling water temperature differences, design cooling water flow rates, design approximation degrees, and the rated operating power corresponding to the current operating condition from the multiple sets of control strategies, are substituted into the first energy consumption model for calculation to obtain the design operating power corresponding to each set of control strategies under the current operating condition.

[0106] Optionally, the current wet-bulb temperature satisfies the following relationship:

[0107] T wb =T·arctan[0.151977(RH+8.313659) 0.50 ]+arctan(T+RH)-

[0108] arctan(RH-1.676331)+0.00391838·RH 1.5 arctan(0.023101RH)-4.686035

[0109] Among them, T wb T represents the current wet-bulb temperature; T represents the current outdoor dry-bulb temperature; RH represents the current outdoor relative humidity.

[0110] In some embodiments, the first energy consumption model is obtained by the controller performing the following steps:

[0111] S201. Obtain historical data information of the cooling tower under multiple historical operating conditions within a preset time period, as well as the historical operating power, historical operating frequency and rated operating power corresponding to the historical data information.

[0112] The historical data information for each historical operating condition includes historical wet-bulb temperature, historical control strategy, and preset wet-bulb temperature, preset cooling water temperature difference, preset cooling water flow rate, and preset approximation degree corresponding to the historical operating condition; wherein the historical control strategy includes historical cooling water temperature difference, historical cooling water flow rate, and historical approximation degree, and the historical wet-bulb temperature is determined by the historical outdoor dry-bulb temperature and historical outdoor relative humidity in the historical operating condition.

[0113] For example, the preset duration is one year, but this preset duration can also be determined according to the needs of the testers. This application embodiment does not impose any restrictions on this.

[0114] S202. Remove the historical data information corresponding to the historical operating frequency being less than the first preset frequency, the historical data information corresponding to the historical operating frequency being greater than the second preset frequency, and the historical data information corresponding to the historical operating power being greater than the first preset power and less than the second preset power from the historical data information under the multiple historical operating conditions to obtain the first data information.

[0115] As can be seen from the above embodiments, since the cooling tower may malfunction during operation, causing abnormalities in its historical operating power or historical operating frequency data, removing the historical data information corresponding to the abnormal historical operating frequency and abnormal historical operating power can eliminate interference factors in the historical data information, thereby improving the accuracy of the first energy consumption model.

[0116] For example, the first preset frequency can be 30Hz, the second preset frequency can be 50Hz, and the first preset power can be... The second preset power can be in, σ1 is the average historical operating power over a preset time period, and σ2 is the average difference of historical operating power over a preset time period. It can be obtained through the following formula:

[0117]

[0118] Where P represents the historical operating power; n represents the number of first data information items within a preset time period.

[0119] σ1 can be obtained using the following formula:

[0120]

[0121] in, The value represents the average historical operating power within a preset time period; n represents the number of first data entries within the preset time period; P i This represents the historical operating power of the i-th time.

[0122] S203. Perform dimensionless processing on the first data information to obtain the second data information.

[0123] For example, the second data information is obtained by dividing the historical operating power, historical wet-bulb temperature, historical cooling water temperature difference, historical approximation degree, and historical cooling water flow rate from the first operating data by the corresponding rated operating power, preset wet-bulb temperature, preset cooling water temperature difference, preset approximation degree, and preset cooling water flow rate, respectively.

[0124] Since the values ​​of historical data in the first running data are generally smaller than the values ​​of preset data, the data after dimensionless processing is not only more accurate, but also enhances the versatility of the first and second data models.

[0125] S204. Perform fitting regression processing on the second data information using the least squares method to obtain the first energy consumption model.

[0126] As can be seen from the above embodiments, by performing fitting regression processing on the second data information using the least squares method, an approximate function can be determined based on the fitted curve, thereby obtaining the coefficients of the first energy consumption model.

[0127] In some embodiments, the first energy consumption model includes:

[0128]

[0129] Where P represents historical operating power; P e ΔT represents the rated operating power; ΔT represents the historical cooling water temperature difference; ΔT e Represents the preset cooling water temperature difference; T app Represents the degree of historical proximity; T app,e T represents the preset approximation degree; wb Represents historical wet-bulb temperature; T wb,e Represents the preset wet-bulb temperature; m cw Represents historical cooling water flow rate; m cw,e represents the preset cooling water flow rate; a, b, c, d, e, r, g, h, i, j, k, l, m, n, o represent the coefficients of the first energy consumption model.

[0130] S103. Determine the target control strategy based on the design operating power of the cooling tower corresponding to each group of control strategies.

[0131] The target control strategy is the control strategy that corresponds to the minimum design operating power among all control strategies. Since different control strategies correspond to different energy consumption under the same operating conditions, controlling the cooling tower with the control strategy corresponding to the minimum design power can minimize the energy consumption of the cooling tower and achieve energy saving.

[0132] S104. Determine the target operating frequency of the cooling tower based on the minimum design operating power and the second energy consumption model.

[0133] In some embodiments, the second energy consumption model is obtained by the controller by performing the following steps: obtaining the rated operating frequency corresponding to the historical operating frequency corresponding to the second data information within a preset time period; performing fitting regression processing on the historical operating power, historical operating power, rated operating power, and rated operating frequency corresponding to the second data information using the least squares method to obtain the second energy consumption model.

[0134] In some embodiments, the second energy consumption model includes:

[0135]

[0136] Where P represents historical operating power; P e f represents the rated operating power; f represents the target operating frequency of the cooling tower; f e A represents the rated operating frequency of the cooling tower; A, B, and C represent the coefficients of the second model.

[0137] Optionally, the coefficients of the second energy consumption model are obtained by the controller performing a least-squares regression process on the historical operating power, rated operating power, and rated operating frequency in the second data information. The method for determining the coefficients of the second energy consumption model is the same as that for the first energy consumption model, and will not be repeated here.

[0138] S105. Control the cooling tower to operate according to the target control strategy and target operating frequency.

[0139] Figure 5 The illustrated embodiments offer at least the following beneficial effects: Since the energy consumption of a cooling tower is related to operating conditions and control strategies, changes in outdoor dry-bulb temperature and relative humidity, or variations in the cooling water temperature difference, cooling water flow rate, and approximation degree, can alter the cooling tower's energy consumption. To address this, this application calculates the design operating power of the cooling tower under various control strategies based on a first energy consumption model. These various design operating powers reflect the energy consumption corresponding to each cooling tower control strategy under the current operating conditions. Since the control strategy corresponding to the minimum design operating power has the lowest energy consumption, this strategy is chosen as the target control strategy. Furthermore, the target operating power is determined based on the minimum design operating power and a second energy consumption model. Thus, controlling the cooling tower's operation according to the target control strategy and target operating frequency minimizes the cooling tower's energy consumption under the current operating conditions, thereby achieving energy savings.

[0140] The control method of the central air conditioning system provided in this solution will be explained in detail below with examples.

[0141] S1. Obtain historical data information for the four cooling towers within one year, including historical wet-bulb temperature (determined by historical outdoor dry-bulb temperature and historical outdoor relative humidity), historical cooling water temperature difference, historical approximation, historical cooling water flow rate, historical operating frequency, historical operating power, and, under the corresponding operating conditions, the rated operating power of each cooling tower (7.5 kW), preset cooling water temperature difference (5°C), and preset cooling water flow rate (303 m³ / h). 3 / h. Among them, the historical operating data includes the operating data of the cooling tower for each period of the year.

[0142] S2. Process the historical data information within the above one year, including:

[0143] Historical data with obviously incorrect operating frequencies of the cooling towers should be removed, such as those with operating frequencies greater than 50Hz or less than 30Hz. Similarly, historical data with obviously incorrect operating power should be removed, such as those with operating power outside the range of (P-2σ1, P+2σ1).

[0144] S3. After dimensionless processing of the first data information processed in S2, the coefficients of the first energy consumption model are obtained by fitting and regressing the dimensionless operational data using the least squares method, thus obtaining the first energy consumption model. For example... Figure 6 The diagram shown illustrates the relationship between the rated operating power ratio and the historical operating power ratio of the cooling tower under multiple historical operating conditions in an embodiment of this application. Figure 7 The diagram shown illustrates the relationship between the rated operating power and historical operating power of the cooling tower under multiple historical operating conditions in this embodiment of the application.

[0145] In this embodiment of the application, the fitting results of the first energy consumption model are shown in Table 1:

[0146] Table 1

[0147] a b c d e r g h 2.0043 -0.2882 -12.3333 5.2924 -0.0714 -1.8483 -3.1369 -4.5973 i j k l m n o <![CDATA[R 2 ]]> 0.8753 7.2898 0.4759 2.8001 17.9269 -7.9639 -5.2168 0.9052

[0148] Among them, R 2 The coefficient of determination, also known as the goodness of fit, R0 2 The closer the value is to 1, the higher the goodness of fit of the model.

[0149] S4. The coefficients of the second energy consumption model are obtained by fitting and regressing using the least squares method, thus obtaining the second energy consumption model. For example... Figure 8 The figure shown is a fitting result diagram of the historical operating power ratio and historical operating frequency ratio of the cooling tower under multiple historical operating conditions in the embodiments of this application.

[0150] S5. Based on the currently detected outdoor dry-bulb temperature of 27℃ and the current outdoor relative humidity, the calculated wet-bulb temperature is 24℃. By setting multiple control strategies, including multiple different design cooling water temperature differences, design cooling water flow rates and design approximations, the cooling tower's multiple design operating power under the current operating conditions and different control strategies is calculated based on the first energy consumption model.

[0151] In this embodiment of the application, the fitting results of the second energy consumption model are shown in Table 2:

[0152] Table 2

[0153] A B C <![CDATA[R 2 ]]> 2.3311 -1.9983 0.6988 0.8597

[0154] Among them, R 2 The coefficient of determination, also known as the goodness of fit, R0 2 The closer the value is to 1, the higher the goodness of fit of the model.

[0155] S6. Based on the current operating conditions, rank the energy consumption according to the magnitude of multiple design operating power under different control strategies, such as... Figure 9 The diagram shown illustrates the relationship between the total cooling energy consumption of the four cooling towers and the number of control strategies in an embodiment of this application.

[0156] Based on the above multiple design operating power values, a target control strategy is determined. The target control strategy is the control strategy with the lowest design operating power among all the control strategies.

[0157] S7. Determine the target operating frequency corresponding to the target operating power through the second energy consumption model.

[0158] In this embodiment, the target operating frequency is shown in Table 3:

[0159] Table 3

[0160] Dry bulb temperature wet-bulb temperature Target operating power Operating frequency Number of operating cooling towers 27℃ 24℃ 393kW 32Hz 4

[0161] S8. Control the cooling towers to operate at the target operating frequency of 32Hz. As shown in Table 3, four cooling towers can be controlled to operate according to the same target control strategy and the same target operating frequency (e.g., 32Hz).

[0162] As can be seen, the above mainly describes the solutions provided by the embodiments of this application from a methodological perspective. To achieve the above functions, the embodiments of this application provide corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, in conjunction with the modules and algorithm steps of the various examples described in the embodiments disclosed herein, the embodiments of this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in a hardware or computer software-driven hardware manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention.

[0163] This application embodiment can divide the controller into functional modules according to the above method example. For example, each function can be divided into a separate functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. Optionally, the module division in this application embodiment is illustrative and only represents one logical functional division; other division methods may be used in the current implementation.

[0164] This application also provides a hardware structure diagram of a controller, such as... Figure 10 As shown, the controller 40 also includes a processor 401, and optionally, a memory 402 and a communication interface 403 connected to the processor 401. The processor 401, memory 402 and communication interface 403 are connected via a bus 404.

[0165] Processor 401 may be a central processing unit (CPU), a general-purpose processor, a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. Processor 401 may also be any other device with processing capabilities, such as a circuit, device, or software module. Processor 401 may also include multiple CPUs, and processor 401 may be a single-core processor or a multi-core processor. Here, "processor" can refer to one or more devices, circuits, or processing cores used to process data (e.g., computer program instructions).

[0166] The memory 402 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or it may be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer. This application embodiment does not impose any limitations on this. The memory 402 may exist independently or may be integrated with the processor 401. The memory 402 may contain computer program code. The processor 401 is used to execute the computer program code stored in the memory 402, thereby implementing the control method provided in this application embodiment.

[0167] The communication interface 403 can be used to communicate with other devices or communication networks (such as Ethernet, radio access network (RAN), wireless local area networks (WLAN), etc.). The communication interface 403 can be a module, circuit, transceiver, or any device capable of communication.

[0168] Bus 404 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. Bus 404 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 10 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0169] This application also provides a computer-readable storage medium including computer-executable instructions that, when run on a computer, cause the computer to execute any of the central air conditioning system control methods provided in the above embodiments.

[0170] This application also provides a computer program product containing computer execution instructions, which, when run on a computer, causes the computer to execute any of the central air conditioning system control methods provided in the above embodiments.

[0171] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software programs, implementation can be, in whole or in part, in the form of a computer program product. This computer program product includes one or more computer-executable instructions. When these computer-executable instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer-executable instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer-executable instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device containing one or more servers, data centers, etc., that can be integrated with the medium. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state disks, SSDs).

[0172] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, disclosure, and appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple instances. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0173] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely illustrative descriptions of the application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and modifications.

[0174] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A central air conditioning system, characterized in that, include: Cooling towers are used to assist in cooling water temperature reduction; A chiller unit, the chiller unit including a condenser; cooling water circulates in a loop formed by the cooling tower and the condenser; The first temperature sensor is used to detect the outdoor dry-bulb temperature. Humidity sensor, used to detect outdoor relative humidity; The controller is electrically connected to the cooling tower, the chiller unit, the first temperature sensor, and the humidity sensor, and the controller is configured to: The current operating condition of the cooling tower and multiple control strategies under the current operating condition are obtained; the current operating condition is determined by the current outdoor dry-bulb temperature and the current outdoor relative humidity, and the control strategies include the design cooling water temperature difference, the design cooling water flow rate, and the design approximation degree. Based on the current operating conditions, the multiple control strategies, and the first energy consumption model, the design operating power of the cooling tower corresponding to each control strategy under the current operating conditions is determined; the first energy consumption model is used to characterize the relationship between the design operating power of the cooling tower and the control strategy. Based on the design operating power of the cooling tower corresponding to each group of control strategies, a target control strategy is determined. The target control strategy is the control strategy with the minimum design operating power among the group of control strategies. The target operating frequency of the cooling tower is determined based on the minimum design operating power and the second energy consumption model. The second energy consumption model is used to characterize the relationship between the design operating power of the cooling tower and the target operating frequency; Control the cooling tower to operate according to the target control strategy and target operating frequency; The first energy consumption model is obtained by the controller performing the following steps: The system acquires historical data information of the cooling tower under multiple historical operating conditions within a preset time period, as well as the historical operating power, historical operating frequency, and rated operating power corresponding to the historical data information. The historical data information under each historical operating condition includes historical wet-bulb temperature, historical control strategy, and preset wet-bulb temperature, preset cooling water temperature difference, preset cooling water flow rate, and preset approximation degree corresponding to the historical operating condition. The historical control strategy includes historical cooling water temperature difference, historical cooling water flow rate, and historical approximation degree. The historical wet-bulb temperature is determined by the historical outdoor dry-bulb temperature and historical outdoor relative humidity in the historical operating condition. The first data information is obtained by removing the historical data information corresponding to historical operating frequencies less than the first preset frequency, historical data information corresponding to historical operating frequencies greater than the second preset frequency, and historical data information corresponding to historical operating power greater than the first preset power and less than the second preset power from the historical data information under the multiple historical operating conditions. The first data information is subjected to dimensionless processing to obtain the second data information; The first energy consumption model is obtained by performing a fitting regression process on the second data information using the least squares method.

2. The central air conditioning system according to claim 1, characterized in that, Also includes: The second temperature sensor is used to detect the first temperature, which is the temperature of the cooling water when it enters the cooling tower. A third temperature sensor is used to detect a second temperature, which is the temperature at which the cooling water flows out of the cooling tower. A flow meter is used to detect the flow rate of cooling water; the second temperature sensor, the third temperature sensor, and the flow meter are electrically connected to the controller.

3. The central air conditioning system according to claim 1 or 2, characterized in that, The first energy consumption model includes: Wherein, P represents the historical operating power; P e ΔT represents the rated operating power; ΔT represents the historical cooling water temperature difference; ΔT e T represents the preset cooling water temperature difference; app T represents the degree of historical approximation. app,e T represents the preset approximation degree; wb T represents the historical wet-bulb temperature; wb,e Represents the preset wet-bulb temperature; m cw Represents the historical cooling water flow rate; m cw,e represents the preset cooling water flow rate; a, b, c, d, e, r, g, h, i, j, k, l, m, n, o represent the coefficients of the first energy consumption model.

4. The central air conditioning system according to claim 2, characterized in that, The second energy consumption model is obtained by the controller performing the following steps: Obtain the rated operating frequency corresponding to the historical operating frequency corresponding to the second data information within the preset time period; The second energy consumption model is obtained by performing a fitting regression process on the historical operating power, historical operating frequency, rated operating power, and rated operating frequency corresponding to the second data information using the least squares method.

5. The central air conditioning system according to claim 4, characterized in that, The second energy consumption model includes: Wherein, P represents the historical operating power; P e f represents the rated operating power; f represents the target operating frequency of the cooling tower; f e A represents the rated operating frequency of the cooling tower; A, B, and C represent the coefficients of the second energy consumption model.

6. A control method for a central air conditioning system, characterized in that, The central air conditioning system includes: Cooling towers are used to assist in cooling water temperature reduction; A chiller unit, the chiller unit including a condenser; cooling water circulates in a loop formed by the cooling tower and the condenser; The first temperature sensor is used to detect the outdoor dry-bulb temperature. Humidity sensor, used to detect outdoor relative humidity; The method includes: The current operating condition of the cooling tower and multiple control strategies under the current operating condition are obtained; the current operating condition is determined by the current outdoor dry-bulb temperature and the current outdoor relative humidity, and the control strategies include the design cooling water temperature difference, the design cooling water flow rate, and the design approximation degree. Based on the current operating conditions, the multiple control strategies, and the first energy consumption model, the design operating power of the cooling tower corresponding to each control strategy under the current operating conditions is determined; the first energy consumption model is used to characterize the relationship between the design operating power of the cooling tower and the control strategy. Based on the design operating power of the cooling tower corresponding to each group of control strategies, a target control strategy is determined. The target control strategy is the control strategy with the lowest design operating power among the group of control strategies. Based on the design operating power and the second energy consumption model corresponding to the target control strategy, the target operating frequency of the cooling tower is determined; the second energy consumption model is used to characterize the relationship between the design operating power of the cooling tower and the target operating frequency. Control the cooling tower to operate according to the target control strategy and target operating frequency; The first energy consumption model is obtained through the following steps: The system acquires historical data information of the cooling tower under multiple historical operating conditions within a preset time period, as well as the historical operating power, historical operating frequency, and rated operating power corresponding to the historical data information. The historical data information under each historical operating condition includes historical wet-bulb temperature, historical control strategy, and preset wet-bulb temperature, preset cooling water temperature difference, preset cooling water flow rate, and preset approximation degree corresponding to the historical operating condition. The historical control strategy includes historical cooling water temperature difference, historical cooling water flow rate, and historical approximation degree. The historical wet-bulb temperature is determined by the historical outdoor dry-bulb temperature and historical outdoor relative humidity in the historical operating condition. The first data information is obtained by removing the historical data information corresponding to historical operating frequencies less than the first preset frequency, historical data information corresponding to historical operating frequencies greater than the second preset frequency, and historical data information corresponding to historical operating power greater than the first preset power and less than the second preset power from the historical data information under the multiple historical operating conditions. The first data information is subjected to dimensionless processing to obtain the second data information; The first energy consumption model is obtained by performing a fitting regression process on the second data information using the least squares method.

7. The method according to claim 6, characterized in that, The central air conditioning system also includes: The second temperature sensor is used to detect the first temperature, which is the temperature of the cooling water when it enters the cooling tower. A third temperature sensor is used to detect a second temperature, which is the temperature at which the cooling water flows out of the cooling tower. A flow meter is used to detect the flow rate of cooling water; the second temperature sensor, the third temperature sensor, and the flow meter are electrically connected to the controller.

8. The method according to claim 6 or 7, characterized in that, The first energy consumption model includes: Wherein, P represents the historical operating power; P e ΔT represents the rated operating power; ΔT represents the historical cooling water temperature difference; ΔT e T represents the preset cooling water temperature difference; app T represents the degree of historical approximation. app,e T represents the preset approximation degree; wb T represents the historical wet-bulb temperature; wb,e Represents the preset wet-bulb temperature; m cw Represents the historical cooling water flow rate; m cw,e represents the preset cooling water flow rate; a, b, c, d, e, r, g, h, i, j, k, l, m, n, o represent the coefficients of the first energy consumption model.

9. The method according to claim 7, characterized in that, The second energy consumption model is obtained through the following steps: Obtain the rated operating frequency corresponding to the historical operating frequency corresponding to the second data information within the preset time period; The second energy consumption model is obtained by performing a fitting regression process on the historical operating power, historical operating frequency, rated operating power, and rated operating frequency corresponding to the second data information using the least squares method.

10. The method according to claim 9, characterized in that, The second energy consumption model includes: Wherein, P represents the historical operating power; P e f represents the rated operating power; f represents the target operating frequency of the cooling tower; f e A represents the rated operating frequency of the cooling tower; A, B, and C represent the coefficients of the second energy consumption model.

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