Air conditioning system and defrosting control method

Abstract

The embodiment of the present application provides an air conditioning system and a defrosting control method, wherein the air conditioning system comprises a compressor, an indoor unit, an outdoor unit, a control valve group, a first circulation loop and a second circulation loop; the compressor comprises a first cylinder and a second cylinder; the indoor unit comprises a first indoor heat exchanger and a second indoor heat exchanger; the outdoor unit comprises a first outdoor heat exchanger and a second outdoor heat exchanger; the control valve group comprises a first four-way valve, a second four-way valve, a first throttling device and a second throttling device; the first cylinder, the first four-way valve, the first outdoor heat exchanger, the first throttling device and the first indoor heat exchanger are arranged on the first circulation loop; the second cylinder, the second four-way valve, the second outdoor heat exchanger, the second throttling device and the second indoor heat exchanger are arranged on the second circulation loop. The air conditioning system of the embodiment of the present application can reduce indoor temperature fluctuation in the defrosting process.

Description

Technical Field

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

[0002] When the air conditioning system is in heating mode, the temperature of the refrigerant flowing through the outdoor heat exchanger is low, which can easily lead to frost formation on the outdoor heat exchanger. Frost formation can affect the heat exchange of the outdoor heat exchanger, and thus affect the heating performance of the entire air conditioning system. Therefore, it is necessary to defrost the outdoor heat exchanger.

[0003] However, in related technologies, air conditioning systems generally use a shutdown and reversing defrosting method in defrosting mode. This defrosting method can affect the indoor heating effect and thus affect comfort. Summary of the Invention

[0004] In view of this, the embodiments of this application aim to provide an air conditioning system and a defrosting control method that can reduce indoor temperature fluctuations during the defrosting process.

[0005] To achieve the above objectives, one embodiment of this application provides an air conditioning system, comprising:

[0006] The compressor includes a first cylinder and a second cylinder;

[0007] An indoor unit, the indoor unit comprising a first indoor heat exchanger and a second indoor heat exchanger;

[0008] An outdoor unit, comprising a first outdoor heat exchanger and a second outdoor heat exchanger;

[0009] A control valve assembly, comprising a first four-way valve, a second four-way valve, a first throttling device, and a second throttling device;

[0010] The first circulation loop includes the first cylinder, the first four-way valve, the first outdoor heat exchanger, the first throttling device, and the first indoor heat exchanger.

[0011] The second circulation loop includes the second cylinder, the second four-way valve, the second outdoor heat exchanger, the second throttling device, and the second indoor heat exchanger.

[0012] In one embodiment, the air conditioning system further includes a signal valve for opening or closing the second circulation loop.

[0013] In one embodiment, the signal valve has a first working port, a second working port, and a third working port; the first cylinder has a first exhaust port and a first return port; and the second cylinder has an opening signal port.

[0014] The first working port is connected to the first circulation loop located between the first exhaust port and the first four-way valve, the second working port is connected to the first circulation loop located between the first return port and the first four-way valve, and the third working port is connected to the opening signal port.

[0015] In one embodiment, the first cylinder has a first exhaust port and a first return port, and the second cylinder has a second exhaust port and a second return port; the first cylinder is connected to the first circulation loop through the first exhaust port and the first return port, and the second cylinder is connected to the second circulation loop through the second exhaust port and the second return port.

[0016] In one embodiment, the first outdoor heat exchanger is located downstream of the second outdoor heat exchanger along the airflow direction; and / or,

[0017] The first indoor heat exchanger is located upstream of the second indoor heat exchanger along the airflow direction.

[0018] One embodiment of this application provides a defrosting control method for an air conditioning system. The air conditioning system includes a compressor, an indoor unit, an outdoor unit, a control valve group, a first circulation loop, and a second circulation loop. The compressor includes a first cylinder and a second cylinder. The indoor unit includes a first indoor heat exchanger and a second indoor heat exchanger. The outdoor unit includes a first outdoor heat exchanger and a second outdoor heat exchanger. The control valve group includes a first four-way valve, a second four-way valve, a first throttling device, and a second throttling device. The first cylinder, the first four-way valve, the first outdoor heat exchanger, the first throttling device, and the first indoor heat exchanger are disposed in the first circulation loop. The second cylinder, the second four-way valve, the second outdoor heat exchanger, the second throttling device, and the second indoor heat exchanger are disposed in the second circulation loop. The method includes:

[0019] The air conditioning system is determined to have run for a preset duration in heating mode, wherein both the first circulation loop and the second circulation loop are in heating mode.

[0020] Obtain the first current temperature of the second outdoor heat exchanger;

[0021] Determine that the first current temperature of the second outdoor heat exchanger meets the first preset condition;

[0022] The air conditioning system is switched to non-stop defrosting mode, and the second four-way valve is switched to switch the second circulation loop from heating operation to cooling operation.

[0023] In one embodiment, before determining that the air conditioning system has run for a preset duration in heating mode, the method further includes:

[0024] Confirm entry into the heating mode;

[0025] Obtain the second lowest initial temperature of the second outdoor heat exchanger during the initial operating period;

[0026] The determination that the first current temperature of the second outdoor heat exchanger meets the first preset condition specifically includes:

[0027] The first difference between the second minimum initial temperature and the first current temperature of the second outdoor heat exchanger is determined to be greater than or equal to a first set value, wherein the first set value is greater than 0°C.

[0028] In one embodiment, after the non-stop defrosting mode ends, the method further includes:

[0029] Control the air conditioning system to switch to the heating mode;

[0030] Obtain the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger;

[0031] The defrosting mode is determined based on the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger, wherein the defrosting mode includes a shutdown defrosting mode and a non-shutdown defrosting mode.

[0032] Control the air conditioning system to switch to the determined defrost mode.

[0033] In one embodiment, determining the defrosting mode based on the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger includes:

[0034] Determine that the second current temperature of the second outdoor heat exchanger meets the second preset condition;

[0035] Determine whether the first current temperature of the first outdoor heat exchanger meets the third preset condition;

[0036] If so, then the defrosting mode is determined to be the shutdown defrosting mode;

[0037] If not, then the defrosting mode is determined to be the non-stop defrosting mode.

[0038] In one embodiment, if the defrosting mode is determined to be a shutdown defrosting mode, then controlling the air conditioning system to switch to the determined defrosting mode includes:

[0039] Control the switching of the first four-way valve and the second four-way valve so that both the first circulation loop and the second circulation loop switch from heating operation to cooling operation.

[0040] In one embodiment, before determining that the air conditioning system has run for a preset duration in heating mode, the method further includes:

[0041] Confirm entry into the heating mode;

[0042] Obtain the second lowest initial temperature of the second outdoor heat exchanger during the initial operating period;

[0043] The determination that the second current temperature of the second outdoor heat exchanger meets the second preset condition specifically includes:

[0044] The second difference between the second minimum initial temperature and the second current temperature of the second outdoor heat exchanger is determined to be greater than or equal to a second set value, wherein the second set value is greater than 0°C.

[0045] In one embodiment, before determining that the air conditioning system has run for a preset duration in heating mode, the method further includes:

[0046] Confirm entry into the heating mode;

[0047] Obtain the first lowest initial temperature of the first outdoor heat exchanger during the initial operating period;

[0048] After determining that the first current temperature of the second outdoor heat exchanger meets the first preset condition, and before controlling the air conditioning system to switch to non-stop defrosting mode, the method further includes:

[0049] Obtain the second current temperature of the first outdoor heat exchanger;

[0050] Record the third difference between the first lowest initial temperature and the second current temperature of the first outdoor heat exchanger;

[0051] The determination of whether the first current temperature of the first outdoor heat exchanger meets the third preset condition specifically includes:

[0052] Determine whether a fourth difference between the first minimum initial temperature and the first current temperature of the first outdoor heat exchanger is greater than or equal to the sum of the third difference and the third set value, wherein the third set value is greater than 0°C.

[0053] In one embodiment, the air conditioning system further includes a signal valve for opening or closing the second circulation loop, and controlling the switching of the second four-way valve to switch the second circulation loop from heating operation to cooling operation includes:

[0054] The signal valve is controlled to shut off the second circulation loop;

[0055] De-energize the second four-way valve;

[0056] Reduce the speed of indoor and outdoor fans;

[0057] The signal valve is controlled to open the second circulation loop.

[0058] In one embodiment, after entering the non-stop defrosting mode, the method further includes:

[0059] Obtain the third current temperature of the second outdoor heat exchanger;

[0060] The third current temperature of the second outdoor heat exchanger is determined to have reached the first target temperature;

[0061] Control the air conditioning system to switch to the heating mode.

[0062] In one embodiment, controlling the air conditioning system to switch to heating mode includes:

[0063] The signal valve is controlled to shut off the second circulation loop;

[0064] Increase the speed of the indoor fan and the outdoor fan to the speed required for heating;

[0065] The signal valve is controlled to open the second circulation loop;

[0066] Power on the second four-way valve.

[0067] This application provides an air conditioning system and a defrosting control method. The air conditioning system is provided with a first circulation loop and a second circulation loop. In heating mode, both the first circulation loop and the second circulation loop operate in heating mode. When the second outdoor heat exchanger needs to be defrosted, the second circulation loop can be controlled to switch from heating operation to cooling operation, while the first circulation loop continues to operate in heating mode. Thus, the heating capacity of the first indoor heat exchanger can be used to reduce the impact of the second indoor heat exchanger on the indoor temperature, thereby reducing indoor temperature fluctuations and improving comfort. Attached Figure Description

[0068] Figure 1 This is a schematic diagram of an air conditioning system according to an embodiment of this application. The hollow arrows at the indoor and outdoor units in the figure indicate the direction of airflow.

[0069] Figure 2 for Figure 1The diagram shows the structure of the air conditioning system. The hollow arrows at the indoor and outdoor units indicate the direction of airflow, and the arrows on the first and second circulation loops indicate the direction of refrigerant flow in the non-stop defrosting mode.

[0070] Figure 3 This is a schematic diagram of the first method of the defrosting control method provided in the embodiments of this application;

[0071] Figure 4 This is a schematic diagram of a second method of the defrosting control method provided in the embodiments of this application;

[0072] Figure 5 A schematic diagram of a third method of the defrosting control method provided in the embodiments of this application;

[0073] Figure 6 A schematic diagram of the fourth method of the defrosting control method provided in the embodiments of this application;

[0074] Figure 7 A schematic diagram of the fifth method of the defrosting control method provided in the embodiments of this application;

[0075] Figure 8 A flowchart of a defrosting control method provided in an embodiment of this application.

[0076] Explanation of reference numerals in the attached figures

[0077] Compressor 10; Opening signal port 11; First return gas port 12; Second return gas port 13; First exhaust port 14; Second exhaust port 15; Indoor unit 20; First indoor heat exchanger 21; Second indoor heat exchanger 22; Outdoor unit 30; First outdoor heat exchanger 31; Second outdoor heat exchanger 32; Control valve group 40; First four-way valve 41; Second four-way valve 42; First throttling device 43; Second throttling device 44; First circulation loop 50; Second circulation loop 60; Signal valve 70; First working port 71; Second working port 72; Third working port 73; First temperature sensor 80; Second temperature sensor 90. Detailed Implementation

[0078] It should be noted that, unless otherwise specified, the embodiments and technical features in the embodiments of this application can be combined with each other, and the detailed descriptions in the specific implementation should be understood as explanations of the purpose of this application and should not be regarded as undue limitations on this application.

[0079] In the description of this application, min represents the time unit minute, s represents the time unit second, and ℃ represents the temperature unit Celsius.

[0080] One embodiment of this application provides an air conditioning system; please refer to [link / reference]. Figure 1The air conditioning system includes a compressor 10, an indoor unit 20, a control valve group 40, a first circulation loop 50, and a second circulation loop 60.

[0081] The compressor 10 includes a first cylinder and a second cylinder, that is, the compressor 10 has at least two cylinders. Figure 1 The first cylinder shown has a first exhaust port 14 and a first return port 12, and the second cylinder has a second exhaust port 15 and a second return port 13. That is to say, the first cylinder and the second cylinder have independent exhaust ports and return ports, or the compressor 10 can be a double-suction double-row compressor 10.

[0082] In some embodiments, the first cylinder and the second cylinder may share the same exhaust port. For example, the gas discharged from the first cylinder and the gas discharged from the second cylinder may be mixed in the compressor 10 and then discharged through the same exhaust port.

[0083] The indoor unit 20 includes a first indoor heat exchanger 21 and a second indoor heat exchanger 22, that is, the indoor unit 20 is equipped with at least two heat exchangers.

[0084] The outdoor unit 30 includes a first outdoor heat exchanger 31 and a second outdoor heat exchanger 32, meaning that the outdoor unit 30 is also equipped with at least two heat exchangers.

[0085] The control valve assembly 40 includes a first four-way valve 41, a second four-way valve 42, a first throttling device 43, and a second throttling device 44.

[0086] The first cylinder, the first four-way valve 41, the first outdoor heat exchanger 31, the first throttling device 43, and the first indoor heat exchanger 21 are installed on the first circulation loop 50, that is, the first outdoor heat exchanger 31 and the first indoor heat exchanger 21 are used together.

[0087] The second cylinder, the second four-way valve 42, the second outdoor heat exchanger 32, the second throttling device 44, and the second indoor heat exchanger 22 are installed on the second circulation loop 60. That is to say, the second outdoor heat exchanger 32 and the second indoor heat exchanger 22 work together, which means that the first circulation loop 50 and the second circulation loop 60 are two independent circulation loops.

[0088] The first circulation loop 50 and the second circulation loop 60 can operate in either cooling or heating mode, respectively.

[0089] by Figure 1Taking the air conditioning system shown as an example, the circulation route of the first circulation loop 50 during cooling operation is as follows: the high-temperature and high-pressure refrigerant is discharged from the first exhaust port 14 of the first cylinder, enters the D port of the first four-way valve 41, and then flows out from the C port of the first four-way valve 41 into the first outdoor heat exchanger 31. After the refrigerant has undergone heat exchange in the first outdoor heat exchanger 31, it flows out from the first outdoor heat exchanger 31 and enters the first indoor heat exchanger 21 through the first throttling device 43 for heat exchange. After the refrigerant has undergone heat exchange, it flows out from the first indoor heat exchanger 21 and flows back to the E port of the first four-way valve 41. Then it flows from the S port of the first four-way valve 41 to the first return port 12 of the first cylinder and flows back into the first cylinder from the first return port 12, thus completing one cooling cycle.

[0090] Please see Figure 1 The circulation route of the second circulation loop 60 during refrigeration operation is as follows: the high-temperature and high-pressure refrigerant is discharged from the second exhaust port 15 of the second cylinder, enters the D port of the second four-way valve 42, and then flows out from the C port of the second four-way valve 42 into the second outdoor heat exchanger 32. After the refrigerant has undergone heat exchange in the second outdoor heat exchanger 32, it flows out from the second outdoor heat exchanger 32 and enters the second indoor heat exchanger 22 through the second throttling device 44 for heat exchange. After the refrigerant has undergone heat exchange, it flows out from the second indoor heat exchanger 22 and flows back to the E port of the second four-way valve 42. Then it flows from the S port of the second four-way valve 42 to the second return port 13 of the second cylinder and flows back into the second cylinder from the second return port 13, thus completing one refrigeration cycle.

[0091] Please see Figure 1 The circulation route of the first circulation loop 50 during heating operation is as follows: the high-temperature and high-pressure refrigerant is discharged from the first exhaust port 14 of the first cylinder, enters the D port of the first four-way valve 41, and then flows out from the E port of the first four-way valve 41 into the first indoor heat exchanger 21. After the refrigerant has undergone heat exchange in the first indoor heat exchanger 21, it flows out from the first indoor heat exchanger 21 and enters the first outdoor heat exchanger 31 through the first throttling device 43 for heat exchange. After the refrigerant has undergone heat exchange, it flows out from the first outdoor heat exchanger 31 and flows back to the C port of the first four-way valve 41. Then it flows from the S port of the first four-way valve 41 to the first return port 12 of the first cylinder and flows back into the first cylinder from the first return port 12, thus completing one heating cycle.

[0092] Please see Figure 1The circulation route of the second circulation loop 60 during heating operation is as follows: the high-temperature and high-pressure refrigerant is discharged from the second exhaust port 15 of the second cylinder, enters the D port of the second four-way valve 42, and then flows out from the E port of the second four-way valve 42 into the second indoor heat exchanger 22. After the refrigerant has undergone heat exchange in the second indoor heat exchanger 22, it flows out from the second indoor heat exchanger 22 and enters the second outdoor heat exchanger 32 through the second throttling device 44 for heat exchange. After the refrigerant has undergone heat exchange, it flows out from the second outdoor heat exchanger 32 and flows back to the C port of the second four-way valve 42. Then it flows from the S port of the second four-way valve 42 to the second return port 13 of the second cylinder and flows back into the second cylinder from the second return port 13, thus completing one heating cycle.

[0093] It should be noted that the above circulation route is mainly used to illustrate the flow direction of the refrigerant. The various physical changes that occur when the refrigerant circulates in the circulation route are common knowledge in this field and will not be elaborated here.

[0094] Another embodiment of this application provides a defrosting control method for use in the air conditioning system provided in any embodiment of this application. Please refer to [link to relevant documentation]. Figure 3 The defrosting control method mainly includes the following steps:

[0095] Step S101: Determine that the running time of the air conditioning system in heating mode has reached the preset time, wherein in heating mode, both the first circulation loop and the second circulation loop are in heating operation.

[0096] In heating mode, the first four-way valve and the second four-way valve are energized, and both the first indoor heat exchanger and the second indoor heat exchanger are used to heat the room.

[0097] Running time refers to the duration of continuous operation of the air conditioning system in heating mode, that is, the duration of heating operation of the first and second circulation loops.

[0098] The preset duration can be determined as needed. For example, the preset duration can be 20 min to 50 min, and more preferably, the preset duration can be 30 min.

[0099] Step S102: Obtain the first current temperature of the second outdoor heat exchanger;

[0100] Specifically, the first current temperature of the second outdoor heat exchanger is the temperature reached by the second outdoor heat exchanger when the air conditioning system has been running in heating mode for a preset duration.

[0101] Please see Figure 1 A second temperature sensor 90 can be installed on the second outdoor heat exchanger 32 to obtain the first current temperature of the second outdoor heat exchanger 32.

[0102] Step S103: Determine that the first current temperature of the second outdoor heat exchanger meets the first preset condition;

[0103] Step S104: Control the air conditioning system to switch to non-stop defrosting mode, and control the second four-way valve to switch the second circulation loop from heating operation to cooling operation.

[0104] Specifically, if the first current temperature of the second outdoor heat exchanger meets the first preset condition, it indicates that the first current temperature of the second outdoor heat exchanger is low and defrosting is required. In this case, the air conditioning system can be switched from heating mode to non-stop defrosting mode. Please refer to [link to relevant documentation]. Figure 2 By controlling the reversing of the second four-way valve 42, the second circulation loop 60 is switched from heating operation to cooling operation. This is equivalent to the refrigerant circulating along the second circulation loop 60 releasing heat when it flows through the second outdoor heat exchanger 32, so that the second outdoor heat exchanger 32 is heated and defrosted. At the same time, the first circulation loop 50 continues to operate in heating mode, which is equivalent to the first indoor heat exchanger 21 continuing to heat the room.

[0105] It should be noted that if the first current temperature of the second outdoor heat exchanger does not meet the first preset condition, the heating mode can be maintained and the running time of the air conditioning system in the heating mode can be recalculated. When the running time reaches the preset time again, step S101 is executed. This means that before entering the non-stop defrosting mode, a judgment can be made every preset time.

[0106] In related technologies, air conditioning systems typically use a shutdown and reversing defrosting method in defrosting mode. During the defrosting process, the indoor heat exchanger cannot heat the room, and a small amount of cold air may even flow into the room, which will cause the indoor temperature to drop and thus affect comfort.

[0107] The air conditioning system in this application embodiment is provided with a first circulation loop and a second circulation loop. In heating mode, both the first circulation loop and the second circulation loop operate in heating mode. When the second outdoor heat exchanger needs to be defrosted, the second circulation loop can be controlled to switch from heating operation to cooling operation, while the first circulation loop continues to operate in heating mode. Thus, the heating capacity of the first indoor heat exchanger can be used to reduce the impact of the second indoor heat exchanger on the indoor temperature, thereby reducing indoor temperature fluctuations and improving comfort.

[0108] Additionally, please see Figure 1Depending on the needs, the first outdoor heat exchanger 31 can be located downstream of the second outdoor heat exchanger 32 along the airflow direction. That is, the airflow generated by the outdoor fan first flows through the second outdoor heat exchanger 32 and then through the first outdoor heat exchanger 31, effectively placing the second outdoor heat exchanger 32 on the windward side. When the outdoor unit 30 frosts during winter heating, the frost layer is mostly located on the windward side of the heat exchanger. Therefore, placing the second outdoor heat exchanger 32 on the windward side allows the frost layer to concentrate mainly on the second outdoor heat exchanger 32, thus facilitating defrosting without shutting down the unit.

[0109] Please see Figure 1 If necessary, the first indoor heat exchanger 21 can also be located upstream of the second indoor heat exchanger 22 along the airflow direction. That is, the airflow generated by the indoor fan first flows through the first indoor heat exchanger 21 and then through the second indoor heat exchanger 22. This is equivalent to the first indoor heat exchanger 21 being located on the windward side. Thus, in the non-stop defrosting mode, the hot airflow generated by the first indoor heat exchanger 21 can be blown towards the second indoor heat exchanger 22, thereby increasing the temperature of the second indoor heat exchanger 22 and shortening the defrosting time.

[0110] In some embodiments, the first outdoor heat exchanger 31 may also be located upstream of the second outdoor heat exchanger 32 along the airflow direction, or the first indoor heat exchanger 21 may also be located downstream of the second indoor heat exchanger 22 along the airflow direction.

[0111] In one embodiment, please refer to Figure 1 The air conditioning system can be equipped with a signal valve 70, which is used to open or close the second circulation loop 60. In other words, the operation of the second circulation loop 60 can be controlled using the signal valve 70. See also... Figure 4 Controlling the reversing of the second four-way valve to switch the second circulation loop from heating operation to cooling operation includes:

[0112] Step S1041: Control signal valve to shut off the second circulation loop;

[0113] Step S1042: De-energize the second four-way valve;

[0114] Step S1043: Reduce the speed of the indoor fan and the outdoor fan;

[0115] Step S1044: Control the signal valve to open the second circulation loop.

[0116] Steps S1042 and S1043 are not sequential.

[0117] In other words, after entering the non-stop defrosting mode, the second circulation loop 60 is first shut off by the control signal valve 70, stopping the refrigerant circulation in the second circulation loop 60 to balance the pressure on the high-pressure and low-pressure sides of the second circulation loop 60. After shutting off the second circulation loop 60, a certain period of time can be waited, such as 30 seconds. Then, the second four-way valve 42 is de-energized, causing it to switch directions and reducing the speed of the indoor and outdoor fans to decrease the airflow. The reduction in the speed of the indoor and outdoor fans can be determined as needed; preferably, both the indoor and outdoor fans can be reduced to their minimum speed. Finally, the control signal valve 70 is opened to reconnect the second circulation loop 60, switching it to cooling operation.

[0118] There are several ways to configure the signal valve 70; for example, please refer to [link to example]. Figure 1 The signal valve 70 has a first working port 71, a second working port 72, and a third working port 73. For example, the signal valve 70 can be a three-way valve. The first cylinder has a first exhaust port 14 and a first return port 12; the second cylinder has an opening signal port 11; the first working port 71 is connected to the first circulation loop 50 located between the first exhaust port 14 and the first four-way valve 41, the second working port 72 is connected to the first circulation loop 50 located between the first return port 12 and the first four-way valve 41, and the third working port 73 is connected to the opening signal port 11.

[0119] Specifically, when the signal valve 70 is de-energized, the second circulation circuit 60 is in a conductive state. When the signal valve 70 is energized, the flow path between the second working port 72 and the third working port 73 is connected, and the high pressure of the second cylinder is released, thereby cutting off the second circulation circuit 60.

[0120] In one embodiment, before determining that the running time has reached a preset duration, the method further includes: determining to enter the heating mode; and obtaining the second lowest initial temperature of the second outdoor heat exchanger during the initial running time period.

[0121] The second minimum initial temperature refers to the lowest temperature value of the second outdoor heat exchanger during a certain initial operating period (i.e., the initial operating period) after entering the heating mode.

[0122] The initial operating time period can be determined as needed. For example, the initial operating time period can be the period from the 7th to the 12th minute after entering the heating mode.

[0123] Please see Figure 1 The second lowest initial temperature can also be obtained by the second temperature sensor 90.

[0124] Additionally, the first preset duration can be calculated after the initial operating period. For example, the first preset duration can be calculated starting from the 13th minute. Alternatively, the initial operating period can also be included within the first preset duration. For instance, the first preset duration can be calculated after the air conditioning system enters heating mode. Assuming the preset duration is 30 minutes, and the initial operating period is the time from the 7th to the 12th minute after entering heating mode, then the 30th minute after the air conditioning system enters heating mode is the time point at which the first current temperature of the second outdoor heat exchanger is first obtained, while the time period from the 7th to the 12th minute after the air conditioning system enters heating mode is the time period for obtaining the second lowest initial temperature.

[0125] Furthermore, determining that the first current temperature of the second outdoor heat exchanger meets the first preset condition can be:

[0126] The first difference between the second minimum initial temperature and the first current temperature of the second outdoor heat exchanger is determined to be greater than or equal to a first set value, wherein the first set value is greater than 0°C.

[0127] Specifically, TCb0 represents the second minimum initial temperature, TCb1 represents the first current temperature of the second outdoor heat exchanger, and S1 represents the first preset value. The first preset condition can be that the second minimum initial temperature TCb0, the first current temperature TCb1 of the second outdoor heat exchanger, and the first preset value S1 satisfy the following condition: TCb0 - TCb1 ≥ S1. The value of S1 can be determined as needed; for example, S1 can be 1℃ to 5℃, and more preferably, S1 can be 2℃. If TCb0 - TCb1 ≥ S1, it means that the first current temperature of the second outdoor heat exchanger is lower than the second minimum initial temperature of the second outdoor heat exchanger during the initial operating period. The second outdoor heat exchanger needs to be defrosted, and therefore, it can enter the non-stop defrosting mode.

[0128] In some embodiments, the first difference between the second minimum initial temperature and the first current temperature of the second outdoor heat exchanger may be greater than the first set value, that is, the second minimum initial temperature TCb0, the first current temperature TCb1 of the second outdoor heat exchanger, and the first set value S1 satisfy: TCb0 - TCb1 > S1.

[0129] In one embodiment, please refer to Figure 5 After the non-stop defrosting mode ends, the method also includes:

[0130] Step S105: Control the air conditioning system to switch to heating mode;

[0131] In other words, the air conditioning system has switched back to normal heating mode.

[0132] For example, after entering the non-stop defrosting mode, the third current temperature of the second outdoor heat exchanger can be obtained. The third current temperature can be obtained in real time or at regular intervals. Let TCb3 represent the third current temperature of the second outdoor heat exchanger and T represent the first target temperature. When it is determined that the third current temperature TCb3 of the second outdoor heat exchanger reaches the first target temperature T1, that is, TCb3≥T1, it means that the temperature of the second outdoor heat exchanger has risen to a suitable temperature and there is no need to continue defrosting. At this time, the air conditioning system can be controlled to switch from the non-stop defrosting mode to the heating mode.

[0133] The value of T1 can be determined as needed. For example, T1 can be 5℃~15℃, and more preferably, T1 can be 8℃.

[0134] Please see Figure 6 Taking an air conditioning system equipped with a signal valve as an example, controlling the air conditioning system to switch to heating mode includes:

[0135] Step S1051: Control signal valve to shut off the second circulation loop;

[0136] Step S1052: Increase the speed of the indoor fan and the outdoor fan to the speed required for heating;

[0137] Step S1053: Control the signal valve to open the second circulation loop;

[0138] Step S1054: Power on the second four-way valve.

[0139] In other words, the second circulation loop can be shut off by controlling the signal valve to stop the refrigerant from circulating. Then, the speeds of both the indoor and outdoor fans can be increased to the normal speeds required for heating. After the indoor and outdoor fans reach the normal speeds required for heating, a certain period of time can be waited, such as 20 seconds, before controlling the signal valve to open the second circulation loop. Finally, the second four-way valve is energized to switch its direction. After the second four-way valve switches its direction, the second circulation loop switches from cooling operation to heating operation, which is equivalent to the air conditioning system switching from non-stop defrosting mode to heating mode.

[0140] Step S106: Obtain the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger;

[0141] Both the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger are temperatures reached at a certain point in time after the air conditioning system switches from non-stop defrosting mode to heating mode. These temperatures can be acquired in real-time or at regular intervals. The times at which the second and first current temperatures of the second and first outdoor heat exchangers are acquired can be the same or different.

[0142] Please see Figure 1 A first temperature sensor 80 can be installed on the first outdoor heat exchanger 31 to obtain the first current temperature of the first outdoor heat exchanger 31.

[0143] Step S107: Determine the defrosting mode based on the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger, wherein the defrosting mode includes a shutdown defrosting mode and a non-shutdown defrosting mode.

[0144] In other words, the defrosting modes of an air conditioning system can include at least two types: shutdown defrosting mode and non-shutdown defrosting mode. Accordingly, the next defrosting mode to be selected can be determined based on the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger.

[0145] Step S108: Control the air conditioning system to switch to the determined defrost mode.

[0146] For example, please refer to Figure 7 Determining the defrost mode based on the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger may include the following steps:

[0147] Step S1071: Determine that the second current temperature of the second outdoor heat exchanger meets the second preset condition;

[0148] There are several ways to determine that the second current temperature of the second outdoor heat exchanger meets the second preset condition. For example, the second preset condition can be that the second difference between the second minimum initial temperature and the second current temperature of the second outdoor heat exchanger is greater than or equal to a second set value, wherein the second set value is greater than 0°C.

[0149] Specifically, TCb2 represents the second current temperature of the second outdoor heat exchanger, and S2 represents the second set value. The second preset condition can be that the second minimum initial temperature TCb0, the second current temperature TCb2 of the second outdoor heat exchanger, and the second set value S2 satisfy: TCb0 - TCb2 ≥ S2. The value of S2 can be determined as needed; for example, S2 can be 1℃ to 5℃, and more preferably, S2 can be 2℃. If TCb0 - TCb2 ≥ S2, it means that the second current temperature of the second outdoor heat exchanger is lower than the second minimum initial temperature of the second outdoor heat exchanger during the initial operating period, and the second outdoor heat exchanger needs to be defrosted.

[0150] In some embodiments, the second difference between the second minimum initial temperature and the second current temperature of the second outdoor heat exchanger may be greater than the second set value, that is, the second minimum initial temperature TCb0, the second current temperature TCb2 of the second outdoor heat exchanger, and the second set value S2 satisfy: TCb0 - TCb2 > S2.

[0151] Step S1072: Determine whether the first current temperature of the first outdoor heat exchanger meets the third preset condition;

[0152] There are multiple ways to determine whether the first current temperature of the first outdoor heat exchanger meets the third preset condition. For example, when obtaining the second lowest initial temperature of the second outdoor heat exchanger during the initial operating period, the first lowest initial temperature of the first outdoor heat exchanger during the initial operating period can also be obtained.

[0153] Accordingly, after determining that the first current temperature of the second outdoor heat exchanger meets the first preset condition, and before controlling the air conditioning system to switch to the non-stop defrosting mode, the method further includes: obtaining the second current temperature of the first outdoor heat exchanger; and recording the third difference between the first minimum initial temperature and the second current temperature of the first outdoor heat exchanger.

[0154] The second current temperature of the first outdoor heat exchanger is the temperature of the first outdoor heat exchanger obtained during the time period before the first current temperature of the second outdoor heat exchanger meets the first preset condition and the air conditioning system switches to the non-stop defrosting mode. In other words, if it is determined that the system needs to switch to the non-stop defrosting mode, a third difference between the first minimum initial temperature and the second current temperature of the first outdoor heat exchanger can be recorded before the switch.

[0155] Let TCa0 represent the first minimum initial temperature, TCa2 represent the second current temperature of the second outdoor heat exchanger, and ΔT represent the third difference. Then, ΔT = TCa0 - TCa2, and record the value of ΔT.

[0156] Further, it is determined whether the first current temperature of the first outdoor heat exchanger meets the third preset condition, specifically: it is determined whether the fourth difference between the first minimum initial temperature and the first current temperature of the first outdoor heat exchanger is greater than or equal to the sum of the third difference and the third set value, wherein the third set value is greater than 0℃.

[0157] Specifically, let TCa1 represent the first current temperature of the first outdoor heat exchanger and S3 represent the third set value. The above judgment can be expressed as: judging whether the first minimum initial temperature TCa0 and the first current temperature TCa1 of the first outdoor heat exchanger satisfy: TCa0-TCa1≥(△T+ S3), where the value of S3 can be determined as needed. For example, S3 can be 1℃~5℃, and more preferably, S3 can be 2℃.

[0158] In another embodiment, it can also be determined whether the first minimum initial temperature TCa0 and the first current temperature TCa1 of the first outdoor heat exchanger satisfy: TCa0 - TCa1 > (ΔT + S3).

[0159] Step S1073: If yes, then confirm that the defrosting mode is the shutdown defrosting mode;

[0160] If the first current temperature of the first outdoor heat exchanger meets the third preset condition, it means that the first current temperature of the first outdoor heat exchanger is also low, and the first outdoor heat exchanger needs to be defrosted.

[0161] For example, if the defrosting mode is determined to be the shutdown defrosting mode, the first four-way valve and the second four-way valve can be switched to enable both the first circulation loop and the second circulation loop to operate in a cooling mode, so as to defrost the first outdoor heat exchanger and the second outdoor heat exchanger.

[0162] For example, the switching method of controlling the first four-way valve and the second four-way valve can be as follows: turn off the compressor, wait for a certain period of time, such as 30 seconds, control the first four-way valve and the second four-way valve to de-energize, turn off the outdoor fan, wait for a certain period of time, such as 10 seconds, turn on the compressor, and turn off the indoor fan.

[0163] In addition, after entering the defrost-off mode, the third current temperature of the first outdoor heat exchanger and the fourth current temperature of the second outdoor heat exchanger can be obtained. It can then be determined whether the third current temperature of the first outdoor heat exchanger has reached the second target temperature, and whether the fourth current temperature of the second outdoor heat exchanger has reached the third target temperature. The third current temperature of the first outdoor heat exchanger and the fourth current temperature of the second outdoor heat exchanger can be obtained in real time or at regular intervals. Let TCa3 represent the third current temperature of the first outdoor heat exchanger, TCb4 represent the fourth current temperature of the second outdoor heat exchanger, T2 represent the second target temperature, and T3 represent the third target temperature. When it is determined that the third current temperature TCa3 of the first outdoor heat exchanger reaches the second target temperature T2, and the fourth current temperature TCb4 of the second outdoor heat exchanger reaches the third target temperature T3 (i.e., TCa3 ≥ T2 and TCb4 ≥ T3), it indicates that the temperatures of both the first and second outdoor heat exchangers have risen to a suitable level, and defrosting is no longer necessary. At this point, the air conditioning system can be switched from the defrost-off mode to the heating mode.

[0164] The values ​​of T2 and T3 can be determined as needed. For example, T2 can be 5℃~15℃, more preferably, T2 can be 8℃, and T3 can be 5℃~15℃, more preferably, T3 can also be 8℃. That is to say, T1, T2 and T3 can take the same value.

[0165] For example, after the defrosting is completed, the compressor can be turned off, the outdoor fan can be turned on, and after a certain period of time, such as 10 seconds, the first four-way valve and the second four-way valve can be energized. After another certain period of time, such as 10 seconds, the compressor can be turned on, and the indoor fan can work according to the normal anti-cold air procedure.

[0166] Step S1074: If not, then confirm that the defrosting mode is the non-stop defrosting mode.

[0167] In other words, if the first current temperature of the first outdoor heat exchanger does not meet the third preset condition, the air conditioning system can be controlled to switch to non-stop defrosting mode, that is, only the second outdoor heat exchanger is defrosted, while the first circulation loop continues to operate in heating mode.

[0168] The following specific embodiment illustrates a defrosting control method of this application. Please refer to [link / reference]. Figure 8 The defrosting control method includes the following steps:

[0169] Step S201: Confirm entry into heating mode;

[0170] In heating mode, both the first circulation loop and the second circulation loop operate in heating mode;

[0171] Step S202: Obtain the first minimum initial temperature TCa0 of the first outdoor heat exchanger during the initial operating period and the second minimum initial temperature TCb0 of the second outdoor heat exchanger during the initial operating period.

[0172] Step S203: Determine that the running time has reached the preset duration t;

[0173] Step S204: Obtain the first current temperature TCb1 of the second outdoor heat exchanger;

[0174] Step S205: Determine whether the second minimum initial temperature TCb0, the first current temperature TCb1 of the second outdoor heat exchanger, and the first set value S1 satisfy: TCb0 - TCb1 ≥ S1. If yes, proceed to step S206; otherwise, proceed to step S204.

[0175] Step S206: Obtain the second current temperature TCa2 of the first outdoor heat exchanger;

[0176] Step S207: Record the third difference ΔT between the first minimum initial temperature TCa0 and the second current temperature TCa2 of the first outdoor heat exchanger, i.e., record ΔT = TCa0 - TCa2;

[0177] Step S208: Switch to non-stop defrosting mode;

[0178] Step S209: Obtain the third current temperature TCb3 of the second outdoor heat exchanger;

[0179] Step S210: Determine whether the third current temperature TCb3 of the second outdoor heat exchanger reaches the first target temperature T1, i.e. whether it satisfies: TCb3≥T1. If yes, proceed to step S211; otherwise, proceed to step S209.

[0180] Step S211: Switch to heating mode;

[0181] Step S212: Obtain the second current temperature TCb2 of the second outdoor heat exchanger and the first current temperature TCa1 of the first outdoor heat exchanger;

[0182] Step S213: Determine whether the second minimum initial temperature TCb0, the second current temperature TCb2 of the second outdoor heat exchanger, and the second set value S2 satisfy: TCb0-TCb2≥S2. If yes, proceed to step S214; otherwise, proceed to step S212.

[0183] In other words, step S213 is to determine whether the second current temperature TCb2 of the second outdoor heat exchanger meets the second preset condition.

[0184] In some implementations, step S212 may only obtain the second current temperature TCb2 of the second outdoor heat exchanger, and if the conditions of step S213 are met, then the first current temperature TCa1 of the first outdoor heat exchanger may be obtained.

[0185] Step S214: Determine whether the first minimum initial temperature TCa0, the first current temperature TCa1 of the first outdoor heat exchanger, the third difference ΔT and the third set value S3 satisfy: TCa0-TCa1≥(ΔT+ S3). If yes, proceed to step S215; otherwise, proceed to step S208.

[0186] In other words, step S214 is to determine whether the first current temperature of the first outdoor heat exchanger meets the third preset condition.

[0187] Step S215: Switch to shutdown defrosting mode;

[0188] Step S216: Obtain the third current temperature TCa3 and the fourth current temperature TCb4 of the first outdoor heat exchanger;

[0189] Step S217: Determine whether the third current temperature TCa3 of the first outdoor heat exchanger reaches the second target temperature T2, and whether the fourth current temperature TCb4 of the second outdoor heat exchanger reaches the third target temperature T3, that is, whether TCa3≥T2 and TCb4≥T3 are satisfied. If yes, proceed to step S218; otherwise, proceed to step S216.

[0190] Step S218: Switch to heating mode;

[0191] Step S219: End.

[0192] The various embodiments / implementations provided in this application can be combined with each other without creating contradictions.

[0193] The above description is merely a preferred embodiment of this application and is not intended to limit the application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. An air conditioning system, characterized by, include: The compressor includes a first cylinder and a second cylinder; An indoor unit, the indoor unit comprising a first indoor heat exchanger and a second indoor heat exchanger; An outdoor unit, comprising a first outdoor heat exchanger and a second outdoor heat exchanger; A control valve assembly, comprising a first four-way valve, a second four-way valve, a first throttling device, and a second throttling device; The first circulation loop includes the first cylinder, the first four-way valve, the first outdoor heat exchanger, the first throttling device, and the first indoor heat exchanger. The second circulation loop, the second cylinder, the second four-way valve, the second outdoor heat exchanger, the second throttling device, and the second indoor heat exchanger are installed on the second circulation loop; A signal valve for opening or closing the second circulation loop, the signal valve having a first working port, a second working port and a third working port; a first cylinder having a first exhaust port and a first return port; a second cylinder having an opening signal port; the first working port communicating with the first circulation loop located between the first exhaust port and the first four-way valve; the second working port communicating with the first circulation loop located between the first return port and the first four-way valve; and the third working port communicating with the opening signal port. The air conditioning system has a non-stop defrosting mode that keeps the first circulation loop in heating mode and switches the second circulation loop from heating mode to cooling mode. The signal valve first cuts off the second circulation loop and then opens the second circulation loop after the second four-way valve reverses, thereby switching the second circulation loop from heating mode to cooling mode.

2. The air conditioning system according to claim 1, characterized in that, The first cylinder has a first exhaust port and a first return port, and the second cylinder has a second exhaust port and a second return port; the first cylinder is connected to the first circulation loop through the first exhaust port and the first return port, and the second cylinder is connected to the second circulation loop through the second exhaust port and the second return port.

3. The air conditioning system according to claim 1, characterized in that, The first outdoor heat exchanger is located downstream of the second outdoor heat exchanger along the airflow direction; and / or, The first indoor heat exchanger is located upstream of the second indoor heat exchanger along the airflow direction.

4. A defrosting control method for an air conditioning system, characterized in that, The air conditioning system includes a compressor, an indoor unit, an outdoor unit, a control valve assembly, a first circulation loop, a second circulation loop, and a signal valve; the compressor includes a first cylinder and a second cylinder; the indoor unit includes a first indoor heat exchanger and a second indoor heat exchanger; the outdoor unit includes a first outdoor heat exchanger and a second outdoor heat exchanger; the control valve assembly includes a first four-way valve, a second four-way valve, a first throttling device, and a second throttling device; the first cylinder, the first four-way valve, the first outdoor heat exchanger, the first throttling device, and the first indoor heat exchanger are arranged in the first circulation loop; the second cylinder, the second four-way valve, and the second outdoor heat exchanger are arranged in the first circulation loop. A heat exchanger, a second throttling device, and a second indoor heat exchanger are disposed on the second circulation loop; the signal valve is used to open or close the second circulation loop, the signal valve having a first working port, a second working port, and a third working port; the first cylinder has a first exhaust port and a first return port; the second cylinder has an opening signal port; the first working port is connected to the first circulation loop located between the first exhaust port and the first four-way valve, the second working port is connected to the first circulation loop located between the first return port and the first four-way valve, and the third working port is connected to the opening signal port; the method includes: The air conditioning system is determined to have run for a preset duration in heating mode, wherein both the first circulation loop and the second circulation loop are in heating mode. Obtain the first current temperature of the second outdoor heat exchanger; Determine that the first current temperature of the second outdoor heat exchanger meets the first preset condition; Control the air conditioning system to switch to non-stop defrosting mode, and control the signal valve to cut off the second circulation loop; De-energize the second four-way valve; Reduce the speed of indoor and outdoor fans; The control signal valve is used to open the second circulation loop, so that the second circulation loop switches from heating operation to cooling operation.

5. The defrosting control method according to claim 4, characterized in that, Before determining that the air conditioning system has run for a preset duration in heating mode, the method further includes: Confirm entry into the heating mode; Obtain the second lowest initial temperature of the second outdoor heat exchanger during the initial operating period; The determination that the first current temperature of the second outdoor heat exchanger meets the first preset condition specifically includes: The first difference between the second minimum initial temperature and the first current temperature of the second outdoor heat exchanger is determined to be greater than or equal to a first set value, wherein the first set value is greater than 0°C.

6. The defrosting control method according to claim 4, characterized in that, After the non-stop defrosting mode ends, the method further includes: Control the air conditioning system to switch to the heating mode; Obtain the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger; The defrosting mode is determined based on the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger, wherein the defrosting mode includes a shutdown defrosting mode and a non-shutdown defrosting mode. Control the air conditioning system to switch to the determined defrost mode.

7. The defrosting control method according to claim 6, characterized in that, The step of determining the defrost mode based on the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger includes: Determine that the second current temperature of the second outdoor heat exchanger meets the second preset condition; Determine whether the first current temperature of the first outdoor heat exchanger meets the third preset condition; If so, then the defrosting mode is determined to be the shutdown defrosting mode; If not, then the defrosting mode is determined to be the non-stop defrosting mode.

8. The defrosting control method according to claim 6, characterized in that, If the defrosting mode is determined to be a shutdown defrosting mode, then controlling the air conditioning system to switch to the determined defrosting mode includes: Control the switching of the first four-way valve and the second four-way valve so that both the first circulation loop and the second circulation loop switch from heating operation to cooling operation.

9. The defrosting control method according to claim 7, characterized in that, Before determining that the air conditioning system has run for a preset duration in heating mode, the method further includes: Confirm entry into the heating mode; Obtain the second lowest initial temperature of the second outdoor heat exchanger during the initial operating period; The determination that the second current temperature of the second outdoor heat exchanger meets the second preset condition specifically includes: The second difference between the second minimum initial temperature and the second current temperature of the second outdoor heat exchanger is determined to be greater than or equal to a second set value, wherein the second set value is greater than 0°C.

10. The defrosting control method according to claim 7, characterized in that, Before determining that the air conditioning system has run for a preset duration in heating mode, the method further includes: Confirm entry into the heating mode; Obtain the first lowest initial temperature of the first outdoor heat exchanger during the initial operating period; After determining that the first current temperature of the second outdoor heat exchanger meets the first preset condition, and before controlling the air conditioning system to switch to non-stop defrosting mode, the method further includes: Obtain the second current temperature of the first outdoor heat exchanger; Record the third difference between the first lowest initial temperature and the second current temperature of the first outdoor heat exchanger; The determination of whether the first current temperature of the first outdoor heat exchanger meets the third preset condition specifically includes: Determine whether a fourth difference between the first minimum initial temperature and the first current temperature of the first outdoor heat exchanger is greater than or equal to the sum of the third difference and the third set value, wherein the third set value is greater than 0°C.

11. The defrosting control method according to claim 4, characterized in that, After entering the non-stop defrosting mode, the method further includes: Obtain the third current temperature of the second outdoor heat exchanger; The third current temperature of the second outdoor heat exchanger is determined to have reached the first target temperature; Control the air conditioning system to switch to the heating mode.

12. The defrosting control method according to claim 11, characterized in that, The control of switching the air conditioning system to heating mode includes: The signal valve is controlled to shut off the second circulation loop; Increase the speed of the indoor fan and the outdoor fan to the speed required for heating; The signal valve is controlled to open the second circulation loop; Power on the second four-way valve.

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