Indirect evaporative cooling unit outdoor fan control method and system

Abstract

The application discloses an indirect evaporative cooling unit outdoor fan control method and system, and the control method comprises the following steps: creating an air volume calculation model; in the wet mode, acquiring the temperature and humidity state parameters of the current outdoor air in real time, and obtaining the minimum unit air intake based on the air volume calculation model; calculating the limit rotating speed corresponding to the outdoor fan in the cooling unit based on the minimum unit air intake; detecting the rotating speed of the outdoor fan in real time, and when the rotating speed of the outdoor fan reaches the limit rotating speed, controlling the cooling unit to enter the mixed mode. Based on the above control method, when the indirect evaporative cooling unit works in the wet mode, the outdoor fan no longer increases the rotating speed to the maximum value according to the indoor energy demand, but increases to the limit rotating speed at most, and when the rotating speed increases to the limit rotating speed, the cooling unit enters the mixed mode, so that the waste of the outdoor fan power can be effectively avoided, and the indoor energy demand can be met in real time.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of air conditioner fan control technology, and particularly relates to an indirect evaporative cooling unit outdoor fan control method and system. BACKGROUND

[0002] In the field of central air conditioning, the indirect evaporative cooling unit is a commonly used air conditioning cooling system in data centers. The indirect evaporative cooling unit is composed of a spraying device, a heat exchange core, an indoor fan, an outdoor fan, a mechanical refrigeration supplement device, a control system and the like. When the unit is used, only the air pipe, water pipe and power distribution need to be installed on site in the data center, and then the unit can be put into use. The unit has three operating modes, namely dry mode, wet mode and mixed mode.

[0003] The dry mode is a heat exchange mode through natural cooling, and is generally used in winter with low temperature. In the case of low outdoor temperature in winter, the outdoor air temperature is low enough to cool the server room return air in the heat exchanger. After passing through the heat exchanger, the outdoor air absorbing heat is discharged to the outdoor by the fan wall. The cooled server room return air is sent into the server room by the indoor fan wall.

[0004] The wet mode is a heat exchange mode based on evaporative cooling. In the case of low outdoor temperature in spring and autumn, the outdoor air temperature is not low enough, and the water pump needs to be started to supplement the refrigeration capacity through high-pressure micro-mist spraying.

[0005] The mixed mode is a heat exchange mode through mechanical refrigeration. In the case of high outdoor temperature in summer, natural cooling cannot meet the refrigeration demand, and the circulating water spray removes part of the heat, and the insufficient part starts the variable frequency compression refrigeration system to supplement the refrigeration capacity.

[0006] For the existing indirect evaporative cooling unit, the operating mode is adjusted according to the outdoor temperature. When operating in the wet mode, the outdoor fan speed is adjusted only according to the indoor capacity demand. In the adjustment process, as the indoor capacity demand increases, whether the heat exchange capacity can continue to increase with the increase of the fan speed, the fan speed is still increased until the maximum value. In this way, the power will surge when the fan speed approaches the maximum value (the power increases in a cubic multiple of the speed), and the increased power is actually invalid because the heat exchange capacity of the heat exchange core cannot be improved by increasing the fan speed, so that not only the power is wasted, but also the indoor cooling demand cannot be met. SUMMARY

[0007] The purpose of the present application is to provide an indirect evaporative cooling unit outdoor fan control method and system which can effectively save power and meet the indoor cooling demand in real time.

[0008] In order to achieve the above object, the application discloses an indirect evaporative cooling unit outdoor fan control method, the working mode of the cooling unit includes dry mode, wet mode and mixed mode, the control method includes

[0009] A wind volume calculation model is created, which is used to calculate the minimum unit air intake volume corresponding to different temperature and humidity state parameters of outdoor air, and the cooling unit has the maximum heat exchange value under the drive of the minimum unit air intake volume;

[0010] In the wet mode, the temperature and humidity state parameters of the current outdoor air are obtained in real time, and the minimum unit air intake volume is obtained based on the wind volume calculation model;

[0011] The minimum unit air intake volume is used to calculate the limit rotating speed corresponding to the outdoor fan in the cooling unit;

[0012] The rotating speed of the outdoor fan is detected in real time, and when the rotating speed of the outdoor fan reaches the limit rotating speed, the cooling unit is controlled to enter the mixed mode.

[0013] Preferably, when the cooling unit enters the mixed mode from the wet mode, the outdoor fan is controlled to keep at the limit rotating speed for a preset time length.

[0014] Preferably, when the cooling unit works in the mixed mode, it is judged whether the rotating speed of the outdoor fan is increased to a corrected rotating speed under the condition that the compressor is turned off, the corrected rotating speed is less than or equal to the limit rotating speed, if yes, it is judged whether the power increased by the rotating speed of the outdoor fan is less than the output power of the current compressor, if yes, the operation of the compressor is stopped, so that the cooling unit enters the wet mode.

[0015] Preferably, the function expression of the wind volume calculation model is L=a*T-b, wherein L is the minimum unit air intake volume, T is the current outdoor wet bulb temperature, a and b are constants, and 4039≤a≤3465.

[0016] The application also discloses an indirect evaporative cooling unit outdoor fan control system, the working mode of the cooling unit includes dry mode, wet mode and mixed mode, and the control system includes

[0017] A wind volume calculation model is created, which is used to calculate the minimum unit air intake volume corresponding to different temperature and humidity state parameters of outdoor air, and the cooling unit has the maximum heat exchange value under the drive of the minimum unit air intake volume;

[0018] a computing module configured to, in the wet mode, acquire a temperature and humidity state parameter of current outdoor air in real time, calculate the minimum unit air intake amount based on the air volume calculation model, and calculate a limit rotating speed corresponding to an outdoor fan in the cooling unit based on the minimum unit air intake amount;

[0019] a first confirming module configured to confirm whether the rotating speed of the outdoor fan reaches the limit rotating speed;

[0020] an adjusting module configured to control the cooling unit to enter a mixed mode according to the feedback of the first confirming module.

[0021] Preferably, the system further comprises a time delay module configured to control the outdoor fan to keep at the limit rotating speed for a preset time length when the cooling unit enters the mixed mode from the wet mode.

[0022] Preferably, the system further comprises a second confirming module and a third confirming module, wherein the second confirming module is configured to confirm whether the rotating speed of the outdoor fan is increased to a modified rotating speed that is less than or equal to the limit rotating speed to meet the energy demand of the indoor side when the compressor is turned off when the cooling unit operates in the mixed mode;

[0023] the third confirming module is configured to confirm whether the power increased by the increase of the rotating speed of the outdoor fan is less than the output power of the current compressor when the result returned by the second confirming module is yes;

[0024] the adjusting module is further configured to stop the operation of the compressor according to the feedback of the third confirming module, so that the cooling unit enters the wet mode.

[0025] Preferably, the function expression of the air volume calculation model is L=a*T-b, wherein L is the minimum unit air intake amount, T is the current outdoor wet-bulb temperature, a and b are constants, and 4039≤a≤3465.

[0026] The application further discloses an indirect evaporative cooling unit outdoor fan control system, which comprises:

[0027] one or more processors;

[0028] a memory;

[0029] and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the programs comprise instructions for executing the indirect evaporative cooling unit outdoor fan control method.

[0030] The present invention also discloses a computer-readable storage medium, characterized in that it includes a computer program, and the computer program can be executed by a processor to implement the above-mentioned indirect evaporative cooling unit external fan control method.

[0031] Compared with the prior art, through the above technical solution of the present invention, the minimum unit air intake volume corresponding to the maximum heat exchange value of the cooling unit adapted to the current environment can be obtained according to the temperature and humidity state parameters of the current outdoor air conditioner, and the maximum wind speed of the outdoor fan can be obtained according to the minimum unit air intake volume. The maximum wind speed is usually less than the maximum wind speed of the outdoor fan. Therefore, when the indirect evaporative cooling unit operates in wet mode, the outdoor fan no longer increases the speed to the maximum value according to the indoor energy demand, but increases to the maximum wind speed. Moreover, when it increases to the maximum wind speed, the cooling unit is controlled to enter the mixed mode, which not only effectively avoids the waste of outdoor fan power, but also can meet the energy demand on the indoor side in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a flow chart of a control method in one embodiment of the present invention.

[0033] Figure 2 This is a flow chart of a control method in another embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the embodiments and the accompanying drawings.

[0035] The present embodiment discloses a method for controlling the external fan of an indirect evaporative cooling unit, which is used to control the operation of the interval evaporative cooling unit to achieve the purpose of saving electricity and improving the user experience. The working modes of the cooling unit in this embodiment include dry mode, wet mode and mixed mode. When working in dry mode, it works based on natural cooling. When working in wet mode, evaporative heat exchange is performed based on the spray mechanism. When working in mixed mode, the compressor and the spray mechanism work at the same time, and the compressor supplements the insufficient evaporative heat exchange. The working principles and structural settings of the above three working modes of the cooling unit belong to mature technologies in this field and will not be described here.

[0036] Based on the above structure of the cooling unit, such as Figure 1 , the control method in this embodiment includes:

[0037] S1: a wind volume calculation model is created, the wind volume calculation model is used to calculate a minimum unit air intake volume corresponding to different temperature and humidity state parameters of outdoor air, and under the drive of the minimum unit air intake volume, the cooling unit has a maximum heat exchange value, that is, when the air intake volume just reaches the minimum unit air intake volume, the heat exchange value of the cooling unit reaches a maximum value corresponding to the current outdoor air state, and even if the unit air intake volume continues to increase, only the power of the outdoor fan will be consumed, and the heat exchange value of the cooling unit will not continue to increase synchronously.

[0038] S2: in the wet mode, the temperature and humidity state parameters of the current outdoor air are obtained in real time, and the minimum unit air intake volume is obtained based on the wind volume calculation model;

[0039] S3: the minimum unit air intake volume is used to calculate a limit rotating speed corresponding to the outdoor fan in the cooling unit;

[0040] S4: during the operation of the cooling unit, the rotating speed of the outdoor fan increases with the increase of the indoor energy demand, therefore, the rotating speed of the outdoor fan is detected in real time, and when the rotating speed of the outdoor fan reaches the limit rotating speed, the cooling unit is controlled to enter the mixed mode. After the cooling unit enters the mixed mode, the indoor energy demand no longer increases due to the supplementary cooling effect of the compressor, so that the rotating speed of the outdoor fan no longer continues to increase.

[0041] In the embodiment, the working state of the indirect evaporative cooling unit in the wet mode is controlled, and the inventive concept is that the rotating speed of the outdoor fan is generated as a limit rotating speed, which is related to the temperature and humidity state of the current outdoor air, that is, the minimum unit air intake volume is calculated based on the preset wind volume calculation model and the temperature and humidity state parameters of the outdoor air as variable parameters, and then the limit rotating speed is generated through the minimum unit air intake volume. Since the minimum unit air intake volume is related to the maximum heat exchange value of the cooling unit, that is, the air intake volume of the outdoor fan is increased, and the heat exchange value of the cooling unit will not increase, so that the rotating speed of the outdoor fan is effectively prevented from being increased to the maximum value without waste of power, so that the purpose of energy saving is achieved, and the cooling unit is adjusted to the mixed mode in time, so that the indoor energy demand is satisfied in time, and the user experience is effectively improved.

[0042] For the wind volume calculation model in the above embodiment, an intelligent model based on a neural network can be used, and historical data is used to train the intelligent model. In addition, for the convenience of implementation, test data can be used for function fitting to obtain a function expression of the wind volume calculation model. In the embodiment, the function expression of the wind volume calculation model is L=a*T-b, wherein L is the minimum unit air intake volume, T is the current outdoor wet-bulb temperature, a and b are constants, and 4039≤a≤3465. Specifically, L=3461.5*T-4037.8.

[0043] On the other hand, when the cooling unit is switched from the wet mode to the mixed mode, in order to avoid the influence on the indoor / outdoor heat exchange due to the sharp change of the outdoor fan speed, resulting in the fluctuation of the indoor air outlet temperature and the excessive fluctuation of the indoor temperature, the outdoor fan is controlled to keep at the limit speed for a preset time length when the cooling unit is switched from the wet mode to the mixed mode. Specifically, taking the 200kW cooling unit as an example, the preset time length is 10min.

[0044] Furthermore, when the cooling unit is operated in the mixed mode, as shown in Figure 2 The control method in the embodiment further comprises the following steps:

[0045] S5: periodically judging whether the power increased by the outdoor fan speed raised to the modified speed under the condition that the compressor is turned off meets the demand of the indoor side, the modified speed being less than or equal to the limit speed, if yes, entering S6, if no, returning to S5;

[0046] S6: judging whether the power increased by the outdoor fan speed is less than the output power of the current compressor, if yes, entering S7, if no, returning to the above step S5;

[0047] S7: stopping the operation of the compressor so that the cooling unit enters the wet mode.

[0048] Specifically, when the compressor is operated at a lower frequency of 30Hz, the output power of the compressor is 9.5kW, at this time, the outdoor fan power is operated at 50% of the maximum speed, and the power is 5.1kW.

[0049] Through calculation, it is found that if the compressor is turned off, the outdoor fan speed is raised to 80% of the maximum speed (less than the limit speed), and the power is raised to 12.2kW. Since (9.5+5.1)-12.2=2.4, after the compressor is turned off, 2.4kW of power can be saved, and then the compressor is controlled to stop operating, so as to further achieve the purpose of energy saving and consumption reduction.

[0050] The application further discloses an indirect evaporative cooling unit outdoor fan control system, wherein the working mode of the cooling unit comprises a dry mode, a wet mode and a mixed mode, and the control system comprises:

[0051] a calculation model creating module, which is used to create an air volume calculation model, the air volume calculation model being used to calculate a minimum unit air volume corresponding to different temperature and humidity state parameters of outdoor air, and the cooling unit having a maximum heat exchange value under the drive of the minimum unit air volume;

[0052] a calculation module, configured to acquire a temperature and humidity state parameter of current outdoor air in real time in the wet mode, and calculate the minimum unit air intake amount based on the air volume calculation model, and calculate a limit rotating speed corresponding to an outdoor fan in the cooling unit based on the minimum unit air intake amount;

[0053] a first confirmation module, configured to confirm whether the rotating speed of the outdoor fan reaches the limit rotating speed;

[0054] an adjustment module, configured to control the cooling unit to enter the mixed mode according to feedback of the first confirmation module.

[0055] Further, the control system in the embodiment further comprises a delay module, configured to control the outdoor fan to keep at the limit rotating speed for a preset time length when the cooling unit enters the mixed mode from the wet mode.

[0056] Further, the control system in the embodiment further comprises a second confirmation module and a third confirmation module, the second confirmation module is configured to confirm whether the rotating speed of the outdoor fan is increased to a modified rotating speed that meets the energy demand of the indoor side in the case of turning off the compressor, the modified rotating speed is less than or equal to the limit rotating speed, when the cooling unit works in the mixed mode;

[0057] the third confirmation module is configured to confirm whether the power increased by the increase of the rotating speed of the outdoor fan is less than the output power of the current compressor, when the result returned by the second confirmation module is yes;

[0058] the adjustment module is further configured to stop the operation of the compressor according to feedback of the third confirmation module, so that the cooling unit enters the wet mode.

[0059] In addition, it should be noted that the working principle and working mode of the control system in the embodiment are described in detail in the above control method, and thus will not be described here.

[0060] The present invention also discloses another cooling unit external fan control system, which includes one or more processors, a memory and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the program includes instructions for executing the control method described above. The processor can adopt a general central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits to execute relevant programs to implement the functions required to be executed by the modules in the control system of the embodiment of the present application, or to execute the control method of the method embodiment of the present application.

[0061] The present invention also discloses a computer-readable storage medium, which includes a computer program, and the computer program can be executed by a processor to perform the control method described above. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or a data center that includes one or more available media. The available medium can be a read-only memory (ROM), or a random access memory (RAM), or a magnetic medium, such as a floppy disk, a hard disk, a tape, a magnetic disk, or an optical medium, such as a digital versatile disc (DVD), or a semiconductor medium, such as a solid state drive (SSD).

[0062] The present application also discloses a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of an electronic device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the electronic device to perform the control method described above.

[0063] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope of the present invention.

Claims

1. A method for controlling an outdoor fan of an indirect evaporative chiller unit, the operating modes of the chiller unit including a dry mode, a wet mode, and a hybrid mode, the method comprising: The control method comprises creating a wind volume calculation model for calculating a minimum unit air intake volume corresponding to different temperature and humidity state parameters of outdoor air, and under the drive of the minimum unit air intake volume, the cooling unit has a maximum heat exchange value; in the wet mode, real-time acquisition of temperature and humidity state parameters of current outdoor air, and based on the wind volume calculation model, the minimum unit air intake volume is obtained; based on the minimum unit air intake volume, a limit rotating speed corresponding to an outdoor fan in the cooling unit is calculated; real-time detection of the rotating speed of the outdoor fan, and when the rotating speed of the outdoor fan reaches the limit rotating speed, the cooling unit is controlled to enter a mixed mode; when the cooling unit works in the mixed mode, it is judged whether the increase of the rotating speed of the outdoor fan to a modified rotating speed under the condition of closing the compressor meets the energy demand of the indoor side, the modified rotating speed being less than or equal to the limit rotating speed, if yes, it is judged whether the power increased by the increase of the rotating speed of the outdoor fan is less than the output power of the current compressor, if yes, the operation of the compressor is stopped, so that the cooling unit enters the wet mode.

2. The method of claim 1, wherein, when the cooling unit enters the mixed mode from the wet mode, the outdoor fan is controlled to keep at the limit rotating speed for a preset time length.

3. The method of claim 1, wherein, The function expression of the wind volume calculation model is L=a*T-b, wherein L is the minimum unit air intake volume, T is the current outdoor wet bulb temperature, a and b are constants, 4039≤a≤3465.

4. An indirect evaporative chiller unit outdoor fan control system, the operating modes of the chiller unit including a dry mode, a wet mode, and a hybrid mode, characterized by, The control system comprises: a calculation model creation module for creating a wind volume calculation model for calculating a minimum unit air intake volume corresponding to different temperature and humidity state parameters of outdoor air, and under the drive of the minimum unit air intake volume, the cooling unit has a maximum heat exchange value; a calculation module for, in the wet mode, real-time acquisition of temperature and humidity state parameters of current outdoor air, and based on the wind volume calculation model, the minimum unit air intake volume is obtained, and based on the minimum unit air intake volume, a limit rotating speed corresponding to an outdoor fan in the cooling unit is calculated; a first confirmation module for confirming whether the rotating speed of the outdoor fan reaches the limit rotating speed; an adjustment module for controlling the cooling unit to enter a mixed mode according to the feedback of the first confirmation module; further comprising a second confirmation module and a third confirmation module, when the cooling unit works in the mixed mode, the second confirmation module is used to confirm whether the increase of the rotating speed of the outdoor fan to a modified rotating speed under the condition of closing the compressor meets the energy demand of the indoor side, the modified rotating speed being less than or equal to the limit rotating speed; the third confirmation module is used to confirm, when the result returned by the second confirmation module is yes, whether the power increased by the increase of the rotating speed of the outdoor fan is less than the output power of the current compressor; the adjustment module is further used to stop the operation of the compressor according to the feedback of the third confirmation module, so that the cooling unit enters the wet mode.

5. The indirect evaporative cooling unit outdoor fan control system of claim 4, wherein, The delay module is further included for controlling the outdoor fan to keep at the limit rotating speed for a preset time length when the cooling unit enters the mixed mode from the wet mode.

6. The indirect evaporative cooling unit outdoor fan control system of claim 4, wherein, The function expression of the air volume calculation model is L=a*T-b, wherein L is the minimum unit air intake, T is the current outdoor wet bulb temperature, a and b are constants, and 4039≤a≤3465.

7. An indirect evaporative chiller unit outdoor fan control system, comprising: Comprise: one or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the programs comprise instructions for executing the indirect evaporative cooling unit outdoor fan control method as claimed in any one of claims 1 to 3.

8. A computer-readable storage medium, characterized in that, Comprise a computer program, which can be executed by a processor to complete the indirect evaporative cooling unit outdoor fan control method as claimed in any one of claims 1 to 3.

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