Air conditioner outdoor fan speed control method and system

Abstract

The application discloses a kind of air conditioner outdoor fan speed control method and system, the method includes: provide a frost temperature interval;When it is detected that air conditioner works in heating mode and meets the following first condition or second condition, the working state of air conditioner outdoor fan is controlled based on first control method;First condition is: ambient temperature is lower than frost temperature interval;Second condition is: ambient temperature is in frost temperature interval, and the low pressure in the compressor of air conditioner is greater than frost critical value;First control method includes: calculating the heat transfer coefficient of the inside of outdoor side heat exchange pipe and the heat transfer coefficient of the outside of outdoor side heat exchange pipe;Adjust fan speed, so that the heat transfer coefficient of the inside of outdoor side heat exchange pipe and the heat transfer coefficient of the outside of outdoor side heat exchange pipe are adapted. Through the above control method, the air volume output by outdoor fan is just the required air volume of heat exchange pipe, so that not only air volume waste is avoided, but also the frosting rate of heat exchange pipe is reduced, and the working performance of air conditioning unit is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioner control, and in particular to an air conditioner outdoor fan rotating speed control method and system. BACKGROUND

[0002] Air conditioner is an indispensable electrical equipment for people's production and life, which creates comfortable temperature for people. When air conditioner cools, the outdoor main machine exhausts hot air, which is forced to flow through the outdoor fan, and the air flows through the fin heat exchanger to cool the refrigerant on the high pressure side of the main machine. When the heat pump heats, the working principle is opposite to that of the cooling, which produces hot water or hot air, and exhausts cold air, which is forced to flow through the fan, and the air flows through the fin heat exchanger to absorb the heat of the air. As can be seen, the outdoor fan plays a crucial role in the heat exchange of the air conditioner, and the electric energy consumed by the outdoor fan accounts for a large proportion in the air conditioner unit.

[0003] For the current air conditioning system, the fan rotating speed is generally adjusted according to the indoor energy demand, which makes the outdoor fan work at the maximum rotating speed most of the time. However, under normal circumstances, the outdoor fan high rotating speed provides a mismatched outside heat exchange coefficient for the heat exchange pipe and the inside heat exchange coefficient for the heat exchange pipe provided by the refrigerant, which leads to the waste of air volume and is not conducive to the energy saving and consumption reduction of the air conditioner unit.

[0004] To this end, the Chinese invention patent "A method and device for controlling the rotating speed of an outdoor fan and a multi-split air conditioner" (application number CN202110724155) improves the control method of the fan rotating speed in order to achieve the purpose of energy saving. The scheme predicts the load of the use side and adjusts the fan rotating speed only according to the low pressure / high pressure. However, this control method does not consider the reliability and safety of the operation of the unit, for example, in a high humidity environment for heating, that is, the air conditioner unit works in heating mode, and the low pressure of the unit is relatively high. According to the control method, the low pressure is simply adjusted to a lower speed, which will make the fin frost faster, thereby causing the performance of the unit to decline too much in a longer period, and the energy saving effect is not ideal. SUMMARY

[0005] The purpose of the present application is to provide an air conditioner outdoor fan rotating speed control method and system which can effectively control the rotating speed of the outdoor fan based on the actual operating state of the air conditioner unit and the current environmental conditions to avoid the waste of air volume.

[0006] In order to achieve the above purpose, the present application discloses an air conditioner outdoor fan rotating speed control method, which comprises:

[0007] A frost temperature interval is provided, which represents an environmental temperature interval that is easily caused to frost the outdoor heat exchanger and is suitable for the installation environment of the air conditioner;

[0008] When it is detected that the air conditioner is working in the heating mode and the first condition or the second condition is met, the working state of the outdoor fan of the air conditioner is controlled based on a first control method;

[0009] The first condition is that the ambient temperature is lower than the frosting temperature range.

[0010] The second condition is that the ambient temperature is in the frosting temperature range and the low pressure in the compressor of the air conditioner is greater than a frosting threshold.

[0011] The first control method comprises:

[0012] The in-pipe heat exchange coefficient of the outdoor heat exchange pipe is calculated based on a preset refrigerant heat exchange coefficient calculation model and the current refrigerant flow.

[0013] The out-pipe heat exchange coefficient of the outdoor heat exchange pipe is calculated based on a preset out-pipe heat exchange coefficient calculation model and the current fan speed.

[0014] The fan speed is adjusted so that the in-pipe heat exchange coefficient and the out-pipe heat exchange coefficient are matched.

[0015] Preferably, the method for adjusting the fan speed comprises:

[0016] The fan speed is adjusted so that the ratio of the in-pipe heat exchange coefficient and the out-pipe heat exchange coefficient is less than a preset target control value.

[0017] Preferably, the method for obtaining the target control value comprises:

[0018] According to the structure of the heat exchange pipe, a plurality of sets of standard experimental data are provided, each set of the standard experimental data comprising a refrigerant flow and a wind volume applied to the outside of the heat exchange pipe matched with the refrigerant flow.

[0019] The fan speed of the outdoor fan corresponding to the wind volume in each set of the standard experimental data is calculated.

[0020] The air conditioner is started based on each set of the standard experimental data, and the total heat exchange amount of the heat exchange pipe is detected.

[0021] The in-pipe heat exchange coefficient and the out-pipe heat exchange coefficient are calculated according to the total heat exchange amount, the heat exchange area of the heat exchange pipe and the heat exchange temperature difference, and the ratio of the in-pipe heat exchange coefficient and the out-pipe heat exchange coefficient is calculated.

[0022] The ratio of the in-pipe heat exchange coefficient and the out-pipe heat exchange coefficient obtained from each set of the standard experimental data is statistically analyzed to obtain the target control value.

[0023] Preferably, the pipe outer heat exchange coefficient calculation model satisfies the following formula one, and the refrigerant heat exchange coefficient calculation model satisfies the following formula two:

[0024]

[0025] Wherein, a w is the pipe outer heat exchange coefficient, a n is the pipe inner heat exchange coefficient, a1, b1 and a2, b2 are correction coefficients, X is the fan speed, M is the refrigerant flow, n is a constant, and 4≤n≤8.

[0026] Preferably, when it is detected that the air conditioner works in the heating mode, if the environment temperature is located in the frosting temperature interval, and the low pressure in the compressor of the air conditioner is less than the frosting critical value, the working state of the outdoor fan of the air conditioner is controlled based on a second control method.

[0027] The second control method comprises:

[0028] A linear function relationship between the fan speed of the outdoor fan and the low pressure value of the compressor is created, and the fan speed decreases with the increase of the low pressure value of the compressor.

[0029] Preferably, when it is detected that the air conditioner works in the heating mode, if the environment temperature is greater than the frosting temperature interval, the working state of the outdoor fan of the air conditioner is controlled based on a third control method.

[0030] The third control method comprises:

[0031] The outdoor fan is controlled to run at a preset lowest speed.

[0032] The application further discloses an air conditioner outdoor fan speed control system, which comprises a controller, and the controller controls the operation of the outdoor fan in the air conditioner based on the air conditioner outdoor fan speed control method.

[0033] The application further discloses an air conditioner outdoor fan speed control system, which comprises:

[0034] One or more processors;

[0035] A memory;

[0036] 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 air conditioner outdoor fan speed control method.

[0037] The application further discloses a computer readable storage medium, which comprises a computer program, and the computer program can be executed by a processor to complete the air conditioner outdoor fan speed control method.

[0038] Compared with the prior art, the above technical scheme of the present application aims at the problem that the outer wall of the heat exchange pipe is prone to frost formation due to the fact that the running state of the outdoor fan does not match the current working state of the air conditioner body and the environmental conditions when the air conditioner works in the heating mode. The first control method is proposed when the air conditioner works in the heating mode and the preset conditions are met. Based on the first control method, the heat exchange coefficients of the inner side and the outer side of the heat exchange pipe are calculated in real time. The heat exchange coefficient of the outer side is related to the fan speed of the outdoor fan. Therefore, when the fan speed is adjusted so that the heat exchange coefficient of the inner side matches the heat exchange coefficient of the outer side, the amount of air output by the outdoor fan is exactly the required amount of air for the heat exchange pipe. In this way, not only is the waste of air volume avoided, but also the frost formation rate of the heat exchange pipe is reduced, and the working performance of the air conditioner body is improved. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The figure is a schematic diagram of the method for controlling the speed of the outdoor fan of the air conditioner in the embodiment of the present application. DETAILED DESCRIPTION

[0040] To explain the technical content, structural features, achieved purposes and effects of the present application in detail, the following will be described in detail in combination with the embodiments and the accompanying drawings.

[0041] The embodiment discloses a method for controlling the speed of the outdoor fan of an air conditioner, so as to effectively control the running state of the outdoor fan during the operation of the air conditioner, which not only provides sufficient air volume for the outdoor heat exchange pipe, but also effectively avoids the waste of air volume. In addition, the control method in the embodiment mainly controls the heating mode of the air conditioner. For this purpose, the control method includes the following steps:

[0042] S1: A frost formation temperature interval is provided, which represents the environmental temperature interval that is easily prone to frost formation on the outdoor heat exchanger and is adapted to the air environment of the installation site of the air conditioner. For this frost formation temperature interval, it is related to the air environment of the installation site of the air conditioner. For example, for the high-humidity and hot regions south of the Yangtze River, the frost formation temperature interval is [-5℃, 5℃].

[0043] S2: After the compressor of the air conditioner is started, it is judged whether the working mode of the air conditioner is the heating mode. If yes, the following step S3 is entered. If no, it indicates that the air conditioner is currently in the cooling mode, and the operation of the air conditioner can be controlled by the existing control method in the art, for example, the operation of the outdoor fan is controlled based on the compression ratio of the air conditioner.

[0044] S3: It is judged whether the current conditions of the air conditioner meet the first condition or the second condition. If yes, the working state of the outdoor fan of the air conditioner is controlled based on the first control method in the following step S4. If no, the operation of the outdoor fan of the air conditioner can be controlled based on the conventional method, and the operation of the outdoor fan of the air conditioner can also be controlled based on the second control method and the third control method in another embodiment.

[0045] The first condition is that the ambient temperature T is lower than the frosting temperature range [T1, T2], i.e., T < T1.

[0046] The second condition is that the ambient temperature T is in the frosting temperature range [T1, T2], i.e., T1 < T < T2, and the low pressure in the compressor of the air conditioner is greater than the frosting critical value.

[0047] For the above two conditions, the ambient temperature is not greater than the frosting temperature range, and for the air conditioner based on the operation of the compressor, the lower the evaporation temperature or the smaller the compressor speed, the lower the refrigerant circulation amount, so that the heat exchange coefficient of the inside of the heat exchange tube is lower, and thus the heat exchange resistance of the outside of the heat exchange tube is reduced, i.e., at this time, the main factor affecting the total heat exchange amount of the heat exchange tube is the heat exchange coefficient of the inside of the heat exchange tube, and even if the heat exchange coefficient of the outside of the heat exchange tube is greatly improved (by improving the speed of the outdoor fan to improve the heat exchange coefficient of the outside of the heat exchange tube), the improvement of the total heat exchange amount of the heat exchange tube is limited. Therefore, when the ambient temperature is not greater than the frosting temperature, it is very meaningful to adjust the fan speed according to the heat exchange coefficient of the inside of the heat exchange tube of the air conditioner for energy saving and consumption reduction of the air conditioner.

[0048] In addition, when T < T1, the absolute humidity of air is small, at this time, the frosting of the fins on the heat exchange tube is no longer a problem affecting the safe operation of the air conditioner, therefore, only the influencing factors of the heat exchange coefficient of the inside of the heat exchange tube can be considered to adjust the fan speed.

[0049] Further, when T1 ≤ T ≤ T2, since the low pressure in the tube is greater than the frosting critical value, the influence of the frosting of the fins on the heat exchange tube on the heat exchange performance can be ignored, so that only the influencing factors of the heat exchange coefficient of the inside of the heat exchange tube are considered to adjust the fan speed.

[0050] Therefore, the first control method in the embodiment includes the following steps S4 to S6.

[0051] S4: calculating the heat exchange coefficient of the inside of the outdoor heat exchange tube based on a preset refrigerant heat exchange coefficient calculation model and the current refrigerant flow. Specifically, after the compressor is started, the low pressure value of the compressor, the compressor speed and the compressor suction temperature are obtained, so as to calculate the refrigerant flow, and then the heat exchange coefficient of the inside of the heat exchange tube is calculated according to the existing structure parameters of the heat exchange tube.

[0052] S5: calculating the heat exchange coefficient of the outside of the outdoor heat exchange tube based on a preset heat exchange coefficient calculation model and the current fan speed. Specifically, the air volume applied to the outside of the heat exchange tube is calculated based on the fan speed of the outdoor fan, and then the heat exchange coefficient of the outside of the heat exchange tube is calculated according to the air volume and the outer wall structure (i.e., the fin structure) of the heat exchange tube.

[0053] S6: adjusting the fan speed so that the heat transfer coefficient inside the tube and the heat transfer coefficient outside the tube are matched.

[0054] Further, the heat transfer coefficient outside the tube satisfies the following formula one, and the heat transfer coefficient of the refrigerant satisfies the following formula two:

[0055]

[0056] wherein a w is the heat transfer coefficient outside the tube, a n is the heat transfer coefficient inside the tube, a1, b1 and a2, b2 are correction coefficients, X is the fan speed, M is the refrigerant flow, n is a constant, and 4≤n≤8.

[0057] Further, the method for adjusting the fan speed comprises:

[0058] adjusting the fan speed so that the ratio K' of the heat transfer coefficient inside the tube and the heat transfer coefficient outside the tube is less than the difference between the preset target control value K and the preset standard value D, i.e., K' is close to K, satisfying the following inequality one:

[0059] |K'-K|≤D.

[0060] Further, the method for obtaining the target control value comprises:

[0061] First, according to the structure of the heat exchange tube, a plurality of sets of standard experimental data are provided, each set of the standard experimental data comprising a refrigerant flow and a wind volume applied to the outside of the heat exchange tube matched with the refrigerant flow.

[0062] Then, the fan speed of the outdoor fan corresponding to the wind volume in each set of the standard experimental data is calculated.

[0063] Next, based on each set of the standard experimental data, the air conditioner is started, i.e., after the air conditioner compressor is started, the refrigerant flow in the air conditioner is the same as the refrigerant flow value in the standard experimental data, the fan speed of the outdoor fan is the same as the fan speed value calculated according to the wind volume in the standard experimental data, and the total heat exchange amount of the heat exchange tube is detected.

[0064] Then, the heat transfer coefficient inside the tube and the heat transfer coefficient outside the tube are calculated according to the total heat exchange amount, the heat exchange area of the heat exchange tube and the heat exchange temperature difference, and the ratio of the heat transfer coefficient inside the tube and the heat transfer coefficient outside the tube is calculated.

[0065] Finally, the ratio of the heat transfer coefficient inside the tube and the heat transfer coefficient outside the tube obtained by statistical analysis of each set of the standard experimental data is obtained to obtain the target control value.

[0066] Specifically, when obtaining a plurality of ratios of the heat transfer coefficient on the inside of the tube to the heat transfer coefficient on the outside of the tube corresponding to each set of standard experimental data, such as K1, K2, …, Kn, etc., an arithmetic mean, variance, or other data processing method can be adopted to process the plurality of ratios to obtain the target control value K.

[0067] On the other hand, when the current state of the air conditioner does not satisfy the first condition and the second condition, two cases are included, one of which is that the ambient temperature is in the frosting temperature interval and the low pressure in the compressor of the air conditioner is less than the frosting critical value, and the other of which is that the ambient temperature is greater than the frosting temperature interval, also T > T2.

[0068] For the first case, that is, when the ambient temperature is in the frosting temperature interval and the low pressure in the compressor of the air conditioner is less than the frosting critical value, the operating state of the air conditioner is controlled based on a second control method, which is:

[0069] A linear function relationship between the fan speed of the outdoor fan and the low pressure value of the compressor is created, and the fan speed decreases with the increase of the low pressure value of the compressor.

[0070] For the second case, that is, when the ambient temperature is greater than the frosting temperature interval, since the heat transfer tube has a large superheat when the ambient temperature on the evaporation side is high, the heat transfer coefficient on the inside of the tube is limited, and therefore, a small air volume is required to effectively utilize the performance of the heat transfer tube. For this reason, the operating state of the air conditioner is controlled based on a third control method, which is:

[0071] The operation of the outdoor fan is controlled at a preset minimum speed.

[0072] In addition, in the first control method and the second control method, the minimum speed of the outdoor fan is also limited, that is, the minimum speed of the outdoor fan is increased, thereby effectively improving the safety performance of the air conditioning unit.

[0073] In summary, this invention discloses a method for controlling the speed of an outdoor air conditioner fan, used to regulate the fan speed in the heating mode of an air conditioner. Specifically, when the ambient temperature is below the frosting temperature range, the fan speed is controlled by the ratio of the heat transfer coefficient inside the tube to the heat transfer coefficient outside the tube, provided by a first control method. When the ambient temperature is within the frosting temperature range and the low pressure inside the compressor is greater than the frosting critical value, the fan speed is controlled by the ratio of the heat transfer coefficient inside the tube to the heat transfer coefficient outside the tube, provided by the first control method. When the ambient temperature is above the frosting temperature range, the outdoor fan is controlled to operate at the lowest speed. When the ambient temperature is within the frosting temperature range and the low pressure inside the compressor is less than the frosting critical value, the fan speed is controlled by low pressure variation. Based on the above control method, the air volume output by the outdoor fan is exactly the air volume required by the heat exchange tube. This not only avoids wasting air volume but also reduces the frosting rate of the heat exchange tube, improving the overall performance of the air conditioner.

[0074] In another preferred embodiment of the present invention, an outdoor fan speed control system for an air conditioner is also disclosed, which includes a controller that controls the operation of the outdoor fan in the air conditioner based on the above-described outdoor fan speed control method.

[0075] This invention also discloses another air conditioner outdoor fan speed 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 configured to be executed by the one or more processors. The programs include instructions for executing the air conditioner outdoor fan speed control method as described above. The processor may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, used to execute relevant programs to achieve the functions required by the modules in the air conditioner outdoor fan speed control system of this application embodiment, or to execute the air conditioner outdoor fan speed control method of this application method embodiment.

[0076] This invention also discloses a computer-readable storage medium comprising a computer program executable by a processor to perform the air conditioner outdoor fan speed control method described above. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center integrating one or more available media. The available medium can be read-only memory (ROM), random access memory (RAM), or magnetic media, such as floppy disks, hard disks, magnetic tapes, magnetic disks, or optical media, such as digital versatile discs (DVDs), or semiconductor media, such as solid-state disks (SSDs).

[0077] This application also discloses a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. The 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 aforementioned air conditioner outdoor fan speed control method.

[0078] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for controlling the rotation speed of an outdoor fan of an air conditioner, characterized by, The application comprises: providing a frosting temperature interval, which represents an environment temperature interval that is easy to cause frosting of the outdoor heat exchanger of the air conditioner and is suitable for the installation environment of the air conditioner; controlling the working state of the outdoor fan of the air conditioner based on a first control method when it is detected that the air conditioner works in the heating mode and the first condition or the second condition is met; the first condition is that the environment temperature is lower than the frosting temperature interval; the second condition is that the environment temperature is in the frosting temperature interval and the low pressure in the compressor of the air conditioner is greater than a frosting critical value; the first control method comprises: calculating the heat exchange coefficient inside the tube of the outdoor heat exchange pipe based on a preset refrigerant heat exchange coefficient calculation model and the current refrigerant flow; calculating the heat exchange coefficient outside the tube of the outdoor heat exchange pipe based on a preset tube outside heat exchange coefficient calculation model and the current fan rotating speed; adjusting the fan rotating speed so that the heat exchange coefficient inside the tube and the heat exchange coefficient outside the tube are suitable for each other; controlling the working state of the outdoor fan of the air conditioner based on a second control method when it is detected that the air conditioner works in the heating mode and the environment temperature is in the frosting temperature interval and the low pressure in the compressor of the air conditioner is less than the frosting critical value; the second control method comprises: creating a linear function relationship between the fan rotating speed of the outdoor fan and the low pressure value of the compressor, and the fan rotating speed decreases with the increase of the low pressure value of the compressor; controlling the working state of the outdoor fan of the air conditioner based on a third control method when it is detected that the air conditioner works in the heating mode and the environment temperature is greater than the frosting temperature interval; the third control method comprises: controlling the operation of the outdoor fan at a preset minimum rotating speed.

2. The outdoor fan speed control method of claim 1, wherein, The method for adjusting the fan rotating speed comprises: adjusting the fan rotating speed so that the ratio of the heat exchange coefficient inside the tube and the heat exchange coefficient outside the tube is less than a preset standard value.

3. The outdoor fan speed control method of claim 2, wherein, The method for obtaining the target control value comprises: providing a plurality of sets of standard experimental data according to the structure of the heat exchange pipe, each set of the standard experimental data comprising a refrigerant flow and a wind volume applied to the outside of the heat exchange pipe suitable for the refrigerant flow; calculating the fan rotating speed of the outdoor fan corresponding to the wind volume in each set of the standard experimental data; starting the air conditioner based on each set of the standard experimental data and detecting the total heat exchange amount of the heat exchange pipe; calculating the heat exchange coefficient inside the tube and the heat exchange coefficient outside the tube and the ratio of the heat exchange coefficient inside the tube and the heat exchange coefficient outside the tube according to the total heat exchange amount, the heat exchange area of the heat exchange pipe and the heat exchange temperature difference; statistically analyzing the ratio of the heat exchange coefficient inside the tube and the heat exchange coefficient outside the tube obtained from each set of the standard experimental data to obtain the target control value.

4. The outdoor fan speed control method of claim 1, wherein, The tube outside heat exchange coefficient calculation model satisfies formula one and the refrigerant heat exchange coefficient calculation model satisfies formula two: wherein a w is a heat transfer coefficient on the outside of the tube, a n is a heat transfer coefficient on the inside of the tube, a1, b1, and a2, b2 are correction coefficients, X is a fan rotation speed, M is a refrigerant flow rate, and n is a constant, 4 ≤ n ≤ 8.

5. An air conditioner outdoor fan speed control system, characterized by, The application comprises a controller, which controls the operation of the outdoor fan in the air conditioner based on the air conditioner outdoor fan rotating speed control method in any one of claims 1 to 4.

6. An air conditioner outdoor fan speed control system, characterized by, The application comprises: 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, the programs comprising instructions for performing the air conditioner outdoor fan speed control method according to any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, A computer program product, comprising a computer program, which can be executed by a processor to complete the air conditioner outdoor fan speed control method according to any one of claims 1 to 4.

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