Piping length determination method and device, air conditioner and computer readable storage medium

Abstract

The embodiment of the invention provides a piping length determining method and device, an air conditioner and a computer readable storage medium, and relates to the technical field of air conditioner control. The main air pipe and the main liquid pipe are connected on the indoor unit side through a main pipe bypass, a four-way valve and a compressor are arranged in the outdoor unit, and a bypass valve is arranged on the main pipe bypass. Heating operation of the four-way valve, opening of the bypass valve and closing of the indoor expansion valves corresponding to the indoor units are controlled; operation parameters of a compressor, bypass pressure of a main pipe bypass, liquid pipe parameters of a main liquid pipe and liquid pipe pressure of the main liquid pipe on the outdoor unit side are obtained; calculating the piping pressure drop of the main liquid pipe according to the bypass pressure and the liquid pipe pressure, and calculating the refrigerant parameters of the main liquid pipe according to the operation parameters of the compressor and the liquid pipe parameters; and the piping length is calculated according to the liquid pipe parameters, the piping pressure drop and the refrigerant parameters. Therefore, the complexity and time consumption of engineering operation can be reduced, and the error rate is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of air conditioner control, and more particularly, to a method and apparatus for determining the length of a refrigerant pipe, an air conditioner, and a computer-readable storage medium. Background Art

[0002] During the operation of an air conditioner, the length of the refrigerant pipe, as a key parameter connecting the outdoor unit and the indoor unit, directly affects the overall performance of the system and the user experience.

[0003] In the related art, generally, the length of the refrigerant pipe can be measured during construction and manually input into the air conditioner. However, this method not only increases the complexity and time consumption of engineering operations but also easily leads to errors due to human mistakes. Summary of the Invention

[0004] The problem to be solved by the present application is how to reduce the complexity and time consumption of engineering operations and reduce the error rate.

[0005] To solve the above problems, the present application provides a method and apparatus for determining the length of a refrigerant pipe, an air conditioner, and a computer-readable storage medium.

[0006] In a first aspect, the present application provides a method for determining the length of a refrigerant pipe, which is applied to an air conditioner. The air conditioner includes an outdoor unit and at least one indoor unit. The outdoor unit is respectively connected to each indoor unit through a main liquid pipe and a main gas pipe. The main gas pipe and the main liquid pipe are connected by a main pipe bypass on the indoor unit side. A four-way valve and a compressor are provided in the outdoor unit, and a bypass valve is provided on the main pipe bypass. The method includes:

[0007] Controlling the four-way valve to operate in heating mode, opening the bypass valve, and closing the indoor expansion valves corresponding to each indoor unit;

[0008] Obtaining the operating parameters of the compressor, the bypass pressure of the main pipe bypass, the liquid pipe parameters of the main liquid pipe, and the liquid pipe pressure of the main liquid pipe on the outdoor unit side;

[0009] Calculating the pipe pressure drop of the main liquid pipe according to the bypass pressure and the liquid pipe pressure, and calculating the refrigerant parameters of the main liquid pipe according to the operating parameters of the compressor and the liquid pipe parameters;

[0010] Calculating the length of the refrigerant pipe according to the liquid pipe parameters, the pipe pressure drop, and the refrigerant parameters.

[0011] In the pipe length determination method provided by the embodiment of the present application, the main air pipe and the main liquid pipe are connected by a main pipe bypass on the indoor unit side, and a bypass valve is provided on the main pipe bypass. When determining the pipe length, based on the heating operation of the four-way valve, the opening of the bypass valve, and the closing of the indoor expansion valve of the indoor unit, the pipe pressure drop of the main liquid pipe can be calculated according to the bypass pressure and the liquid pipe pressure of the main liquid pipe on the outdoor unit side, and the refrigerant parameters corresponding to the main liquid pipe can be calculated according to the operating parameters of the compressor and the liquid pipe parameters of the main liquid pipe. Then, the pipe length can be calculated according to the liquid pipe parameters, pipe pressure drop, and refrigerant parameters of the main liquid pipe. In this way, the air conditioner can directly calculate the pipe length according to the relevant parameters of the main liquid pipe without the need for workers to measure and manually input, so the complexity and time consumption of engineering operations can be reduced, and the error rate can be reduced.

[0012] In an alternative embodiment, the compressor is connected to the four-way valve through a suction pipe, and a suction pipe expansion valve is provided on the suction pipe. Before obtaining the operating parameters of the compressor, the bypass pressure of the main pipe bypass, the liquid pipe parameters of the main liquid pipe, and the liquid pipe pressure of the main liquid pipe on the outdoor unit side, the method further includes:

[0013] Controlling the suction pipe expansion valve to open at a first preset opening degree and obtaining the suction pressure of the compressor;

[0014] Adjusting the opening degree of the suction pipe expansion valve according to the suction pressure and a preset pressure threshold.

[0015] In the pipe length determination method provided by the embodiment of the present application, a suction pipe expansion valve is provided on the suction pipe between the compressor and the four-way valve. By adjusting the opening degree of the suction pipe expansion valve, the suction pressure of the compressor is adjusted, so that the compressor operates stably.

[0016] In an alternative embodiment, the pressure threshold includes a first pressure threshold and a second pressure threshold, and the second pressure threshold is less than the first pressure threshold; the adjusting the opening degree of the suction pipe expansion valve according to the suction pressure and a preset pressure threshold includes:

[0017] If the suction pressure is greater than or equal to the first pressure threshold, the opening degree of the suction pipe expansion valve is lowered according to a preset opening degree adjustment value;

[0018] If the suction pressure is less than the second pressure threshold, the opening degree of the suction pipe expansion valve is increased according to the opening degree adjustment value.

[0019] The pipe length determination method provided by the embodiment of the present application, when the suction pressure is greater than or equal to the first pressure threshold, adjusts the opening degree of the suction pipe expansion valve downward according to a preset opening degree adjustment value. If the suction pressure is less than the second pressure threshold, the opening degree of the suction pipe expansion valve is adjusted upward according to the opening degree. Therefore, it can ensure that the suction pressure of the compressor always remains within a reasonable range, avoiding the problem of unstable operation of the compressor caused by too high or too low suction pressure.

[0020] In an alternative embodiment, an outdoor expansion valve is provided on the outdoor unit side of the main liquid pipe. Before obtaining the operating parameters of the compressor, the bypass pressure of the main pipe bypass, the liquid pipe parameters of the main liquid pipe, and the liquid pipe pressure on the outdoor unit side of the main liquid pipe, the method further includes:

[0021] Controlling the outdoor expansion valve to open according to a second preset opening degree.

[0022] The pipe length determination method provided by the embodiment of the present application also needs to open the outdoor expansion valve according to the second preset opening degree before calculating the pipe length, so as to ensure that the refrigerant temperature is maintained within an appropriate cooling range and avoid the situation where the refrigerant temperature cannot continue to be cooled after dropping to room temperature.

[0023] In an alternative embodiment, the operating parameters include suction parameters, exhaust parameters, the cylinder volume of the compressor, and the rotational speed of the compressor. The liquid pipe parameters include the inner diameter of the liquid pipe, and the refrigerant parameters include the exhaust refrigerant density and the refrigerant flow rate. Calculating the refrigerant parameters corresponding to the main liquid pipe according to the operating parameters of the compressor and the liquid pipe parameters includes:

[0024] Calculating the suction refrigerant density and the exhaust refrigerant density according to the suction parameters and the exhaust parameters;

[0025] Calculating the refrigerant flow rate according to the cylinder volume of the compressor, the rotational speed of the compressor, the suction refrigerant density, and the inner diameter of the liquid pipe.

[0026] The pipe length determination method provided by the embodiment of the present application calculates the suction refrigerant density and the exhaust refrigerant density through the suction parameters and the exhaust parameters, and calculates the refrigerant flow rate according to the cylinder volume of the compressor, the rotational speed of the compressor, the suction refrigerant density, and the inner diameter of the liquid pipe. Therefore, the refrigerant parameters corresponding to the main liquid pipe can be accurately calculated, and further the accuracy of the pipe length calculation can be ensured.

[0027] In an alternative embodiment, the suction parameters include the suction temperature and the suction pressure, and the exhaust parameters include the exhaust temperature and the exhaust pressure. Calculating the suction refrigerant density and the exhaust refrigerant density according to the suction parameters and the exhaust parameters includes:

[0028] Calculate the suction refrigerant density based on the suction pressure and the suction temperature, and calculate the discharge refrigerant density based on the discharge temperature and the discharge pressure.

[0029] In an alternative embodiment, the calculating the refrigerant flow rate based on the compressor cylinder volume, the compressor speed, the suction refrigerant density, and the inner diameter of the liquid pipe includes:

[0030] Calculate the refrigerant circulation amount of the main liquid pipe based on the compressor cylinder volume, the compressor speed, and the suction refrigerant density;

[0031] Calculate the refrigerant flow rate based on the refrigerant circulation amount and the inner diameter of the liquid pipe.

[0032] In a second aspect, the present application provides a piping length determination device applied to an air conditioner. The air conditioner includes an outdoor unit and at least one indoor unit. The outdoor unit is respectively connected to each indoor unit through a main liquid pipe and a main gas pipe. The main gas pipe and the main liquid pipe are bypass-connected through a main bypass on the indoor unit side. A four-way valve and a compressor are provided in the outdoor unit, and a bypass valve is provided on the main bypass. The device includes:

[0033] A control module for controlling the four-way valve to operate in heating mode, opening the bypass valve, and closing the indoor expansion valves corresponding to each indoor unit;

[0034] An acquisition module for acquiring the operating parameters of the compressor, the bypass pressure of the main bypass, the liquid pipe parameters of the main liquid pipe, and the liquid pipe pressure of the main liquid pipe on the outdoor unit side;

[0035] A calculation module for calculating the piping pressure drop of the main liquid pipe based on the bypass pressure and the liquid pipe pressure, and calculating the refrigerant parameters of the main liquid pipe based on the operating parameters of the compressor and the liquid pipe parameters;

[0036] The calculation module is further configured to calculate the piping length based on the liquid pipe parameters, the piping pressure drop, and the refrigerant parameters.

[0037] The piping length determination device provided by the embodiment of the present application has the main air pipe and the main liquid pipe bypass-connected through a main pipe bypass on the indoor unit side, and a bypass valve is provided on the main pipe bypass. When determining the piping length, the control module can be used to control the four-way valve to operate in heating mode, open the bypass valve, and close the indoor expansion valves corresponding to each indoor unit; the acquisition module is used to acquire the operating parameters of the compressor, the bypass pressure of the main pipe bypass, the liquid pipe parameters of the main liquid pipe, and the liquid pipe pressure of the main liquid pipe on the outdoor unit side; the calculation module is used to calculate the piping pressure drop of the main liquid pipe according to the bypass pressure and the liquid pipe pressure, calculate the refrigerant parameters corresponding to the main liquid pipe according to the operating parameters of the compressor and the liquid pipe parameters, and calculate the piping length according to the liquid pipe parameters, the piping pressure drop, and the refrigerant parameters. In this way, the air conditioner can directly calculate the piping length according to the relevant parameters of the main liquid pipe without the need for workers to measure and manually input, so the complexity and time consumption of engineering operations can be reduced, and the error rate can be reduced.

[0038] In a third aspect, the present application provides an air conditioner, including an outdoor unit and at least one indoor unit. The outdoor unit is respectively connected to each indoor unit through a main liquid pipe and a main air pipe. The main air pipe and the main liquid pipe are bypass-connected through a main pipe bypass on the indoor unit side. A four-way valve and a compressor are provided in the outdoor unit. A bypass valve is provided on the main pipe bypass. The air conditioner further includes a main controller, and the main controller is used to implement the method according to any one of the foregoing embodiments.

[0039] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by the main controller, the method according to any one of the foregoing embodiments can be implemented. Description of the Drawings

[0040] Figure 1 It is a schematic structural diagram of a multi-connected air conditioner in the prior art;

[0041] Figure 2 It is a schematic structural diagram of an air conditioner provided by an embodiment of the present application;

[0042] Figure 3 It is a schematic flow diagram of a piping length determination method provided by an embodiment of the present application;

[0043] Figure 4 It is a schematic diagram of the refrigerant flow direction;

[0044] Figure 5 It is a schematic block diagram of a piping length determination device provided by an embodiment of the present application.

[0045] Description of the reference numerals: 100 - control module; 110 - acquisition module; 120 - calculation module. Detailed implementation mode

[0046] During the operation of the air conditioner, the pipe length, as a key parameter connecting the outdoor unit and the indoor unit, directly affects the overall performance of the system and the user experience.

[0047] Taking the multi-connected air conditioner as an example, as the multi-connected air conditioner gradually adapts to more diverse construction conditions, the allowable pipe length is constantly increasing, expanding from about 100 meters in the past to more than 200 meters. Although this change improves the installation flexibility, it also brings new technical challenges. For example, during the refrigeration process, in order to ensure the user's comfort, the system needs to precisely control the compressor speed to maintain the evaporation temperature of the indoor heat exchanger within an appropriate range. However, the pressure drop in the main gas pipe will cause the evaporation pressure to change, thereby affecting the evaporation temperature and ultimately may lead to insufficient or excessive refrigeration capacity. Therefore, it is particularly important to accurately control the compressor speed considering the pipe length.

[0048] In addition, during the oil return operation of returning the lubricating oil remaining in the main gas pipe or other pipes to the compressor, the pipe length also plays a key role. According to the actual measurement results, the pipe length directly affects the time required for the oil return operation. If the oil return time is insufficient, it may lead to a reduction in the amount of compressor oil, thereby affecting the normal operation of the compressor; while an overly long oil return time may reduce the user's comfort experience. Therefore, it is also essential to reasonably set the oil return time based on the pipe length.

[0049] However, traditional methods usually rely on construction workers to manually measure the pipe length and input it into the air conditioner system. This method not only increases the complexity and time consumption of engineering operations but also easily leads to incorrect input due to human operation errors.

[0050] To solve this problem, some methods for automatically estimating the pipe length during the commissioning stage of the air conditioner have been proposed in the prior art.

[0051] Figure 1 For the structural schematic diagram of the multi-connected air conditioner in the prior art, as Figure 1 shown, the methods for estimating the pipe length in the prior art usually calculate the evaporation pressure based on the temperature of the indoor heat exchanger during the refrigeration operation, and further calculate the pipe pressure drop of the refrigerant flowing through the main gas pipe by combining the difference between the evaporation pressure and the suction pressure. Subsequently, the pipe length is estimated through the refrigerant flow rate in the main gas pipe and the derived formula after the deformation of the Darcy-Weisbach formula.

[0052] This method can avoid the errors caused by manual input and simplify the construction process. However, there is a significant technical bottleneck in this method: Since modern air-conditioning system designs tend to increase the inner diameter of the main air pipe to reduce the piping pressure drop and thus improve the overall performance, the piping pressure drop value used to infer the piping length becomes very small. For example, in a 200-meter-long main air pipe, the piping pressure drop may be only about 3 bar. The accuracy of the pressure sensor usually installed on a multi-split air conditioner is 1% of the maximum measurement range, that is, there may be an error of 0.5 bar in a 50-bar pressure sensor. In this case, the error of the pressure sensor will have a huge impact on the inferred result of the piping length, and may cause the inferred error to reach more than 30 meters.

[0053] It can be seen that although this method can achieve the function of automatically inputting the piping length to a certain extent, due to the small piping pressure drop value, the influence of the pressure sensor error is amplified, so the accuracy of the inferred piping length is finally difficult to meet the actual requirements.

[0054] Based on this, the embodiments of the present application provide a method, device, air conditioner and computer-readable storage medium for determining the piping length, so as to reduce the complexity and time consumption of engineering operations, reduce the error rate, while reducing the calculation error of the piping length and improving the calculation accuracy of the piping length.

[0055] To make the above objects, features and advantages of the present application more obvious and understandable, the following will describe the specific embodiments of the present application in detail with reference to the accompanying drawings.

[0056] It should be noted that the method for determining the piping length provided by the embodiments of the present application can be applied to ordinary unitary air conditioners or multi-split air conditioners. Since the piping of multi-split air conditioners is relatively long, the method for determining the piping length provided by the embodiments of the present application will be exemplarily introduced below taking multi-split air conditioners as an example.

[0057] Figure 2 For a schematic structural diagram of the air conditioner provided by the embodiments of the present application, please refer to Figure 2 , taking this air conditioner as a multi-split air conditioner and including two indoor units as an example, the air conditioner provided by the embodiments of the present application will be exemplarily introduced.

[0058] In this embodiment, the air conditioner includes an outdoor unit and at least one indoor unit. The outdoor unit is respectively connected to each indoor unit through a main liquid pipe and a main air pipe. The main air pipe and the main liquid pipe are connected by a main pipe bypass on the indoor unit side. A four-way valve and a compressor are provided in the outdoor unit, and a bypass valve is provided on the main pipe bypass.

[0059] Optionally, since there is high-pressure gas refrigerant flowing through the main pipe bypass, the diameter of the main pipe bypass and the caliber of the solenoid valve can be the same as or larger than the diameter of the compressor exhaust pipe.

[0060] Optionally, the air conditioner may further include a main controller, which may be disposed in the outdoor unit to implement the pipe length determination method provided in the embodiments of the present application.

[0061] Next, taking the air conditioner described above Figure 2 as the execution subject, the pipe length determination method provided in the embodiments of the present application will be introduced exemplarily in combination with the flow schematic diagram.

[0062] Specifically, Figure 3 a flow schematic diagram of the pipe length determination method provided in the embodiments of the present application is shown in Figure 3 , and the method includes:

[0063] Step S20, control the four-way valve to operate in heating mode, open the bypass valve, and close the indoor expansion valves corresponding to each indoor unit.

[0064] Optionally, when the user needs to determine the pipe length, the user may send a pipe length calculation instruction to the air conditioner. At this time, the air conditioner may first confirm whether there is a pipe length calculation history. If there is, the historical data may be directly called. If not, the pipe length calculation is performed.

[0065] First, the air conditioner can control the four-way valve, the bypass valve, and the indoor expansion valve to limit the refrigerant flow path between the main liquid pipe and the main gas pipe.

[0066] In this embodiment, Figure 4 a refrigerant flow direction schematic diagram is shown in Figure 4 . When the four-way valve operates in heating mode, the bypass valve is open, and the indoor expansion valves corresponding to the indoor units are all closed, the high-pressure gas refrigerant discharged from the compressor will move to the indoor unit side through the main gas pipe, flow to the main pipe bypass, flow into the main liquid pipe through the main pipe bypass, and return to the outdoor unit.

[0067] Step S21, obtain the operating parameters of the compressor, the bypass pressure of the main pipe bypass, the liquid pipe parameters of the main liquid pipe, and the liquid pipe pressure of the main liquid pipe on the outdoor unit side.

[0068] Step S22, calculate the pipe pressure drop of the main liquid pipe according to the bypass pressure and the liquid pipe pressure, and calculate the refrigerant parameters corresponding to the main liquid pipe according to the operating parameters of the compressor and the liquid pipe parameters.

[0069] Optionally, the bypass pressure of the main pipe bypass refers to the pressure value of the refrigerant when passing through the main pipe bypass. Since the bypass valve is opened, the refrigerant can flow from the main liquid pipe into the main gas pipe. The pressure distribution during this process directly reflects the state of the refrigerant at the end of the main liquid pipe, while the liquid pipe pressure on the outdoor unit side of the main liquid pipe is the pressure value when the refrigerant enters the main liquid pipe. These two pressure values respectively represent the pressure states at both ends of the main liquid pipe. Therefore, by measuring the pressure difference between these two points, the total pressure drop experienced by the refrigerant when flowing in the main liquid pipe can be directly reflected.

[0070] In this embodiment, the pipe pressure drop can be calculated by the formula ΔP = P B - P L where ΔP represents the pipe pressure drop, P B represents the bypass pressure, and P L represents the liquid pipe pressure.

[0071] Optionally, the refrigerant parameters of the main liquid pipe are key indicators describing the flow state of the refrigerant in the main liquid pipe. These parameters directly affect the refrigerant flow distribution, pressure loss in the main liquid pipe, and the calculation results of the pipe length. Therefore, accurately determining the refrigerant parameters is crucial for the performance evaluation of the entire system.

[0072] In this embodiment, the refrigerant parameters can be calculated based on the relevant operating parameters of the compressor and in combination with the liquid pipe parameters of the main liquid pipe.

[0073] Step S23: Calculate the pipe length according to the liquid pipe parameters, pipe pressure drop, and refrigerant parameters.

[0074] Optionally, the pipe length refers to the length of the main gas pipe. Since the main liquid pipe and the main gas pipe together constitute the round-trip path of the refrigerant between the indoor unit and the outdoor unit, the length of the main liquid pipe is usually very close to that of the main gas pipe. Based on the integrity and symmetry of the refrigerant cycle of the air-conditioning system, the pipe length can be calculated through the liquid pipe parameters, pipe pressure drop, and refrigerant parameters of the main liquid pipe.

[0075] In the pipe length determination method provided by the embodiment of the present application, the main gas pipe and the main liquid pipe are connected through the main pipe bypass on the indoor unit side, and a bypass valve is provided on the main pipe bypass. When determining the pipe length, on the basis of controlling the four-way valve to operate in heating mode, the bypass valve to be opened, and the indoor expansion valve of the indoor unit to be closed, the pipe pressure drop of the main liquid pipe can be calculated according to the bypass pressure and the liquid pipe pressure on the outdoor unit side of the main liquid pipe, and the refrigerant parameters corresponding to the main liquid pipe can be calculated according to the operating parameters of the compressor and the liquid pipe parameters of the main liquid pipe. Then, the pipe length can be calculated according to the liquid pipe parameters, pipe pressure drop, and refrigerant parameters of the main liquid pipe. In this way, the air conditioner can directly calculate the pipe length according to the relevant parameters of the main liquid pipe, without the need for staff to measure and manually input, so the complexity and time consumption of engineering operations can be reduced, and the error rate can be reduced.

[0076] Optionally, since the inner diameter of the main liquid pipe is smaller than that of the main gas pipe, as shown in Table 1, the inner diameter of the main liquid pipe is often only about 55% of the inner diameter of the main gas pipe. Since the piping pressure drop is inversely proportional to the pipe inner diameter, the piping pressure drop corresponding to the main liquid pipe with a smaller inner diameter is larger. For example, when the length of the main liquid pipe is 200 meters, its piping pressure drop may be more than 10 bar. Therefore, even if the error of the pressure sensor is 0.5 bar, the estimated error of its piping length is only about 10 meters, compared with the prior art where the error reaches more than 30 meters. The piping length determination method provided by the embodiments of the present application can greatly reduce the error, thereby improving the calculation accuracy of the piping length.

[0077] Table 1

[0078]

[0079]

[0080] Optionally, during the process of determining the piping length of the air conditioner, the compressor is a core component, and whether it operates stably directly affects the performance and reliability of the entire system. However, considering that during actual operation, the suction pressure of the compressor may fluctuate due to changes in the system operating conditions, such as uneven refrigerant flow, pipeline blockage, or improper opening degree of the expansion valve. These problems may cause the compressor to operate unstably and even pose a risk of damage. Therefore, how to ensure that the compressor is always within an appropriate suction pressure range under different operating conditions has become a technical problem that needs to be solved urgently.

[0081] If the suction pressure is too high or too low, it may cause a decline in system performance or equipment damage. To solve this problem, the piping length determination method provided by the embodiments of the present application realizes effective control of the suction pressure by setting a suction piping expansion valve on the suction piping between the compressor and the four-way valve and dynamically adjusting the opening degree of the expansion valve. Specifically, please continue to refer to Figure 2 , the compressor and the four-way valve are connected through the suction piping, and a suction piping expansion valve is provided on the suction piping. Before the above step S21, the air conditioner can also control the suction piping expansion valve to open according to a first preset opening degree and obtain the suction pressure of the compressor; adjust the opening degree of the suction piping expansion valve according to the suction pressure and a preset pressure threshold.

[0082] Optionally, the first preset opening degree may refer to the opening degree corresponding to reducing the pressure of the high-pressure gas refrigerant to the suction pressure range within which the compressor can operate reliably during refrigeration or heating operation, and its specific value can be set according to the actual application situation.

[0083] In a possible implementation manner, the first preset opening degree may be about 30% of the maximum opening degree of the suction piping expansion valve.

[0084] Optionally, by opening the suction pipe expansion valve at a first preset opening degree, a basic suction flow state can be initially set, thereby providing a stable initial condition for subsequent fine adjustment.

[0085] Optionally, to ensure that the pressure drop does not increase due to insufficient expansion valve orifice diameter, the maximum opening orifice diameter of the suction pipe expansion valve can be designed to be the same as or larger than the diameter of the compressor suction pipe, thereby avoiding a reduction in system capacity caused by an increase in pressure drop.

[0086] Next, the opening degree of the suction pipe expansion valve can be dynamically adjusted according to the suction pressure measured during the actual operation process.

[0087] In a possible implementation manner, to ensure that the compressor suction pressure always remains within a reasonable range and avoid unstable operation of the compressor caused by too high or too low suction pressure, the pressure threshold can include a first pressure threshold and a second pressure threshold, and the second pressure threshold is less than the first pressure threshold.

[0088] On this basis, the air conditioner can determine whether the suction pressure is greater than or equal to the first pressure threshold and whether it is less than the second pressure threshold. If the suction pressure is greater than or equal to the first pressure threshold, the opening degree of the suction pipe expansion valve is lowered according to a preset opening degree adjustment value. If the suction pressure is less than the second pressure threshold, the opening degree of the suction pipe expansion valve is increased according to the opening degree adjustment value.

[0089] Optionally, the first pressure threshold and the second pressure threshold can be determined according to the normal range of the compressor suction pressure. In a possible implementation manner, the first pressure threshold can be 12 bar, and the second pressure threshold can be 8 bar.

[0090] Optionally, the opening degree adjustment value can be set by comprehensively considering the change range of the pressure reduction amount and the system stability requirement according to the relationship between the opening degree change and the pressure change.

[0091] In a possible implementation manner, the opening degree adjustment value can be 5% of the maximum opening degree. This is based on the following two reasons: on the one hand, if the opening degree change is less than 5%, the change in the pressure reduction amount is not sufficient to cause a significant change in the suction pressure, and the expected adjustment effect cannot be achieved; on the other hand, if the opening degree change is too large, it will cause a sharp change in the pressure reduction amount, resulting in unstable suction pressure and affecting the overall system performance. Therefore, a 5% opening degree change is the best balance point between ensuring the adjustment effect and system stability.

[0092] In this embodiment, when the suction pressure reaches above 12 bar, to prevent the excessive suction pressure from affecting the reliability of the compressor, the air conditioner can reduce the opening degree of the expansion valve by 5% of the maximum opening degree, so as to effectively reduce the suction pressure to the safe range while not causing too drastic a change in the pressure reduction amount, thereby maintaining the stability of the system. Conversely, when the suction pressure is less than 8 bar, to avoid the insufficient suction pressure from affecting the operation of the compressor, the opening degree of the expansion valve can be increased by 5% of the maximum opening degree.

[0093] Optionally, considering that in the method for determining the pipe length of an air conditioner, the effective cooling and circulation of the refrigerant are the key links to ensure the normal operation of the system. However, in practical applications, there may be a situation where the refrigerant cannot be sufficiently cooled. This problem usually stems from the fact that the refrigerant flow rate or pressure in the main liquid pipe fails to meet the design requirements, resulting in a decrease in the refrigeration or heating effect of the system. Therefore, how to ensure that the refrigerant can be cooled as expected has become an important problem to be solved by this technical solution.

[0094] Based on this, the pipe length determination method provided by the embodiment of the present application can adjust the opening degree of the outdoor expansion valve to ensure that the refrigerant temperature is maintained within an appropriate cooling range, avoiding the situation where the refrigerant cannot be further cooled after the temperature drops to room temperature.

[0095] Based on this, please continue to refer to Figure 2 , an outdoor expansion valve is further provided on the outdoor unit side of the main liquid pipe. Before the above step S21, the air conditioner also needs to control the outdoor expansion valve to open according to a second preset opening degree.

[0096] Optionally, the second preset opening degree can be set according to the actual application situation. In a possible implementation manner, the second preset opening degree can be the maximum opening degree of the outdoor expansion valve.

[0097] In this embodiment, during the operation of estimating the pipe length, to avoid the reduction of the system capacity caused by the increase in pressure drop, the outdoor expansion valve is set to the maximum opening degree. This setting not only ensures that the refrigerant can flow smoothly in the main liquid pipe but also minimizes unnecessary pressure losses.

[0098] Optionally, the maximum opening degree diameter of the outdoor expansion valve can be equal to or larger than the diameter of the compressor suction pipe.

[0099] Optionally, after setting each component in the air conditioner, the air conditioner can obtain relevant parameters to calculate the pipe length.

[0100] Optionally, the air conditioner can obtain the operating parameters of the compressor, the bypass pressure of the main pipe bypass, and the liquid pipe pressure on the outdoor unit side of the main liquid pipe through sensors arranged at corresponding positions. In a possible implementation manner, please continue to refer to Figure 2, a pressure sensor on the outdoor unit side can be provided near the main liquid pipe, a pressure sensor for the main pipe bypass can also be provided on the main pipe bypass, a suction pressure sensor and a suction temperature sensor can be provided on the suction pipe of the compressor, and similarly, an exhaust pressure sensor and an exhaust temperature sensor can be provided on the exhaust pipe, so that the air conditioner can obtain corresponding parameters through these sensors.

[0101] Next, a possible implementation method is provided for how to calculate the refrigerant parameters corresponding to the main liquid pipe according to the operating parameters of the compressor and the liquid pipe parameters.

[0102] In a possible implementation method, the operating parameters may include suction parameters, exhaust parameters, the cylinder volume of the compressor, and the rotational speed of the compressor, the liquid pipe parameters include the inner diameter of the liquid pipe, and the refrigerant parameters include the exhaust refrigerant density and the refrigerant flow rate. Then, the air conditioner can calculate the suction refrigerant density and the exhaust refrigerant density according to the suction parameters and the exhaust parameters, and calculate the refrigerant flow rate according to the cylinder volume of the compressor, the rotational speed of the compressor, the suction refrigerant density, and the inner diameter of the liquid pipe.

[0103] Based on this, the air conditioner can calculate the pipe length according to the inner diameter of the liquid pipe, the pipe pressure drop, the exhaust refrigerant density, and the refrigerant flow rate.

[0104] In a possible implementation method, the pipe length can be calculated by the following formula:

[0105] L = 2×ΔP×D×10 5 / (λ×ρ d ×V 2 )

[0106] Wherein, L represents the pipe length, ΔP represents the pipe pressure drop, D represents the inner diameter of the liquid pipe, λ represents the pipe friction coefficient, ρ d represents the exhaust refrigerant density, V 2 represents the refrigerant flow rate.

[0107] Optionally, the suction parameters may include the suction temperature and the suction pressure, and the exhaust parameters may include the exhaust temperature and the exhaust pressure. Based on this, the air conditioner can calculate the suction refrigerant density according to the suction pressure and the suction temperature, and calculate the exhaust refrigerant density according to the exhaust temperature and the exhaust pressure.

[0108] Optionally, the air conditioner can first calculate the refrigerant circulation amount of the main liquid pipe according to the cylinder volume of the compressor, the rotational speed of the compressor, and the suction refrigerant density, and then calculate the refrigerant flow rate according to the refrigerant circulation amount and the inner diameter of the liquid pipe.

[0109] In a possible implementation method, the refrigerant circulation amount can be calculated by the following formula: G = B×10 -6 ×F×ρ s

[0110] Among them, G represents the refrigerant circulation amount, B represents the cylinder volume of the compressor (ml / rev), F represents the rotational speed of the compressor, and ρ s represents the suction refrigerant density.

[0111] In a possible implementation manner, the refrigerant flow rate can be calculated by the following formula:

[0112] V = G / (π / 4 × D 2 × 10 -6 )

[0113] Among them, V represents the refrigerant flow rate, G represents the refrigerant circulation amount, and D represents the inner diameter of the liquid pipe.

[0114] The embodiment of the present application also provides a device for determining the piping length. Figure 5 For a block diagram of the device for determining the piping length provided by the embodiment of the present application, please refer to Figure 5 , the device for determining the piping length includes a control module 100, an acquisition module 110, and a calculation module 120.

[0115] The control module 100 is used to control the four-way valve to operate in heating mode, open the bypass valve, and close the indoor expansion valves corresponding to each indoor unit.

[0116] It can be understood that the control module 100 can also be used to execute the above step S20.

[0117] The acquisition module 110 is used to acquire the operating parameters of the compressor, the bypass pressure of the main pipe bypass, the liquid pipe parameters of the main liquid pipe, and the liquid pipe pressure of the main liquid pipe on the outdoor unit side.

[0118] It can be understood that the acquisition module 110 can also be used to execute the above step S21.

[0119] The calculation module 120 is used to calculate the piping pressure drop of the main liquid pipe according to the bypass pressure and the liquid pipe pressure, and calculate the refrigerant parameters of the main liquid pipe according to the operating parameters of the compressor and the liquid pipe parameters.

[0120] It can be understood that the calculation module 120 can also be used to execute the above step S22.

[0121] The calculation module 120 is also used to calculate the piping length according to the liquid pipe parameters, the piping pressure drop, and the refrigerant parameters.

[0122] It can be understood that the calculation module 120 can also be used to execute the above step S23.

[0123] Optionally, the control module 100 is further configured to control the suction pipe expansion valve to open at a first preset opening degree, and obtain the suction pressure of the compressor; and adjust the opening degree of the suction pipe expansion valve according to the suction pressure and a preset pressure threshold.

[0124] Optionally, if the suction pressure is greater than or equal to a first pressure threshold, the control module 100 is further configured to lower the opening degree of the suction pipe expansion valve according to a preset opening degree adjustment value; if the suction pressure is less than a second pressure threshold, the control module 100 is further configured to increase the opening degree of the suction pipe expansion valve according to the opening degree adjustment value.

[0125] Optionally, the control module 100 is further configured to control the outdoor expansion valve to open at a second preset opening degree.

[0126] Optionally, the calculation module 120 is further configured to calculate the suction refrigerant density and the discharge refrigerant density according to the suction parameters and the discharge parameters; and calculate the refrigerant flow rate according to the compressor cylinder volume, the compressor speed, the suction refrigerant density, and the liquid pipe inner diameter.

[0127] Optionally, the calculation module 120 is further configured to calculate the suction refrigerant density according to the suction pressure and the suction temperature, and calculate the discharge refrigerant density according to the discharge temperature and the discharge pressure.

[0128] Optionally, the calculation module 120 is further configured to calculate the refrigerant circulation amount of the main liquid pipe according to the compressor cylinder volume, the compressor speed, and the suction refrigerant density; and calculate the refrigerant flow rate according to the refrigerant circulation amount and the liquid pipe inner diameter.

[0129] The embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by the main controller, the pipe length determination method provided by the embodiment of the present application can be implemented.

[0130] Although the present application is disclosed as above, the present application is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. A method for determining the length of a pipe, characterized in that, Applied to an air conditioner, the air conditioner includes an outdoor unit and at least one indoor unit. The outdoor unit is respectively connected to each indoor unit through a main liquid pipe and a main gas pipe. The main gas pipe and the main liquid pipe are connected in a bypass manner through a main bypass on the indoor unit side. A four-way valve and a compressor are provided in the outdoor unit, and a bypass valve is provided on the main bypass. The method includes: Controlling the four-way valve to operate in heating mode, the bypass valve to open, and the indoor expansion valves corresponding to each indoor unit to close; Obtaining the operating parameters of the compressor, the bypass pressure of the main bypass, the liquid pipe parameters of the main liquid pipe, and the liquid pipe pressure of the main liquid pipe on the outdoor unit side; Calculating the piping pressure drop of the main liquid pipe according to the bypass pressure and the liquid pipe pressure, and calculating the refrigerant parameters of the main liquid pipe according to the operating parameters of the compressor and the liquid pipe parameters; Calculating the piping length according to the liquid pipe parameters, the piping pressure drop, and the refrigerant parameters.

2. The method according to claim 1, characterized in that The compressor is connected to the four-way valve through a suction piping, and a suction piping expansion valve is provided on the suction piping. Before obtaining the operating parameters of the compressor, the bypass pressure of the main bypass, the liquid pipe parameters of the main liquid pipe, and the liquid pipe pressure of the main liquid pipe on the outdoor unit side, the method further includes: Controlling the suction piping expansion valve to open at a first preset opening degree and obtaining the suction pressure of the compressor; Adjusting the opening degree of the suction piping expansion valve according to the suction pressure and a preset pressure threshold.

3. The method according to claim 2, characterized in that, The pressure threshold includes a first pressure threshold and a second pressure threshold, and the second pressure threshold is less than the first pressure threshold. Adjusting the opening degree of the suction piping expansion valve according to the suction pressure and the preset pressure threshold includes: if the suction pressure is greater than or equal to the first pressure threshold, then reducing the opening degree of the suction piping expansion valve by a preset opening degree adjustment value; If the suction pressure is less than the second pressure threshold, then increasing the opening degree of the suction piping expansion valve by the opening degree adjustment value.

4. The method according to claim 1, wherein An outdoor expansion valve is provided on the main liquid pipe on the outdoor unit side. Before obtaining the operating parameters of the compressor, the bypass pressure of the main bypass, the liquid pipe parameters of the main liquid pipe, and the liquid pipe pressure of the main liquid pipe on the outdoor unit side, the method further includes: Controlling the outdoor expansion valve to open at a second preset opening degree.

5. The method according to claim 1, characterized in that The operating parameters include suction parameters, discharge parameters, the cylinder volume of the compressor, and the rotational speed of the compressor. The liquid pipe parameters include the inner diameter of the liquid pipe. The refrigerant parameters include the discharge refrigerant density and the refrigerant flow rate. Calculating the refrigerant parameters corresponding to the main liquid pipe according to the operating parameters of the compressor and the liquid pipe parameters includes: Calculating the suction refrigerant density and the discharge refrigerant density according to the suction parameters and the discharge parameters; calculating the refrigerant flow rate according to the cylinder volume of the compressor, the rotational speed of the compressor, the suction refrigerant density, and the inner diameter of the liquid pipe.

6. The method according to claim 5, characterized in that, The suction parameters include the suction temperature and the suction pressure, and the discharge parameters include the discharge temperature and the discharge pressure; calculating the suction refrigerant density and the discharge refrigerant density according to the suction parameters and the discharge parameters includes: Calculating the suction refrigerant density according to the suction pressure and the suction temperature, and calculating the discharge refrigerant density according to the discharge temperature and the discharge pressure.

7. The method according to claim 5, wherein Calculating the refrigerant flow rate according to the compressor cylinder volume, the compressor speed, the suction refrigerant density, and the inner diameter of the liquid pipe includes: Calculating the refrigerant circulation amount of the main liquid pipe according to the compressor cylinder volume, the compressor speed, and the suction refrigerant density; Calculating the refrigerant flow rate according to the refrigerant circulation amount and the inner diameter of the liquid pipe.

8. A piping length determination device, characterized in that, Applied to an air conditioner, the air conditioner includes an outdoor unit and at least one indoor unit. The outdoor unit is respectively connected to each indoor unit through a main liquid pipe and a main gas pipe. The main gas pipe and the main liquid pipe are connected in a bypass manner through a main pipe on the indoor unit side. A four-way valve and a compressor are provided in the outdoor unit, and a bypass valve is provided on the main pipe bypass. The device includes: A control module for controlling the four-way valve to operate in heating mode, opening the bypass valve, and closing the indoor expansion valves corresponding to each indoor unit; An acquisition module for acquiring the operating parameters of the compressor, the bypass pressure of the main pipe bypass, the liquid pipe parameters of the main liquid pipe, and the liquid pipe pressure of the main liquid pipe on the outdoor unit side; A calculation module for calculating the piping pressure drop of the main liquid pipe according to the bypass pressure and the liquid pipe pressure, and calculating the refrigerant parameters of the main liquid pipe according to the operating parameters of the compressor and the liquid pipe parameters; The calculation module is further configured to calculate the piping length according to the liquid pipe parameters, the piping pressure drop, and the refrigerant parameters.

9. An air conditioner, characterized in that, An air conditioner includes an outdoor unit and at least one indoor unit. The outdoor unit is respectively connected to each indoor unit through a main liquid pipe and a main gas pipe. The main gas pipe and the main liquid pipe are connected in a bypass manner through a main pipe on the indoor unit side. A four-way valve and a compressor are provided in the outdoor unit, and a bypass valve is provided on the main pipe bypass. The air conditioner further includes a main controller, and the main controller is configured to implement the method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, A computer program is stored thereon, and when the computer program is executed by the main controller, the method according to any one of claims 1-7 can be implemented.

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