Air conditioning system and defrosting control method thereof

Abstract

The invention relates to the technical field of air conditioners, in particular to an air conditioning system and a defrosting control method thereof. The air conditioning system aims at solving the problem that the indoor temperature is reduced in the defrosting process of an existing air conditioning system. In order to achieve the purpose, the air conditioning system and the defrosting control method thereof are provided, the air conditioning system comprises a double-return-air compressor, an indoor heat exchanger, a first outdoor heat exchanger and a second outdoor heat exchanger, and two defrosting loops are formed between the double-return-air compressor and the first outdoor heat exchanger and between the double-return-air compressor and the second outdoor heat exchanger respectively. According to the technical scheme, the refrigerant cannot flow into the indoor heat exchanger after the outdoor heat exchanger releases heat under the defrosting condition, so that it is guaranteed that the indoor temperature cannot be reduced, and good use experience is provided for a user.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to an air conditioning system and a defrosting control method thereof. Background Art

[0002] During the winter heating process of a heat pump air conditioner, the high-temperature and high-pressure refrigerant is discharged from the compressor and enters the indoor heat exchanger to release heat, and then absorbs heat through the outdoor heat exchanger. At this time, the outdoor heat exchanger serves as the evaporator on the low-pressure side, and the water molecules in the humid air will precipitate and freeze on the surface of the outdoor heat exchanger. As the temperature continues to drop, the frost or ice on the surface of the heat exchanger becomes thicker and thicker, affecting the air volume of the outdoor heat exchanger, which in turn causes the temperature to drop, forming a vicious cycle, seriously affecting the indoor heating air outlet temperature and effect experience.

[0003] To ensure the heating effect of the heat pump air conditioner, the outdoor heat exchanger is usually defrosted. However, in the existing technology, the temperature of the outdoor heat exchanger is generally increased by controlling the air conditioning cooling, thereby melting the ice and frost on the surface of the outdoor heat exchanger. However, this defrosting method will cause the indoor temperature to drop, thereby affecting the user experience.

[0004] Accordingly, this field requires a new technical solution to solve the above problems. Summary of the Invention

[0005] In order to solve at least one of the above problems in the prior art, that is, to solve the problem of indoor temperature reduction during the defrosting process in the existing air-conditioning system, the present application provides an air-conditioning system, which includes a dual-return air compressor, an indoor heat exchanger, a first outdoor heat exchanger, and a second outdoor heat exchanger.

[0006] The exhaust port of the dual return air compressor is in communication with the first port of the indoor heat exchanger;

[0007] The second port of the indoor heat exchanger is communicated with the first port of the first outdoor heat exchanger and the first port of the second outdoor heat exchanger respectively;

[0008] The second port of the first outdoor heat exchanger and the second port of the second outdoor heat exchanger are respectively connected to the first return air port and the second return air port of the dual return air compressor;

[0009] Wherein, the dual return air compressor forms a first defrost circuit and a second defrost circuit with the first outdoor heat exchanger and the second outdoor heat exchanger respectively.

[0010] When the above-mentioned technical solution is adopted, the first outdoor heat exchanger and the second outdoor heat exchanger can be defrosted respectively through the first defrost circuit and the second defrost circuit, and in the case of defrosting, the refrigerant will not flow into the indoor heat exchanger after releasing heat in the first outdoor heat exchanger or the second outdoor heat exchanger, thereby ensuring that the indoor temperature will not drop and providing users with a good user experience.

[0011] In the preferred technical solution of the above air-conditioning system, the air-conditioning system further comprises a first four-way reversing valve and a second four-way reversing valve.

[0012] The first port, the second port, the third port and the fourth port of the first four-way reversing valve are respectively connected to the exhaust port of the double return air compressor, the first port of the indoor heat exchanger, the first return air port of the double return air compressor and the second port of the first outdoor heat exchanger;

[0013] The first port, the second port, the third port and the fourth port of the second four-way reversing valve are respectively connected to the exhaust port of the double return air compressor, the first port of the indoor heat exchanger, the second return air port of the double return air compressor and the second port of the second outdoor heat exchanger.

[0014] In the preferred technical solution of the above air-conditioning system, the air-conditioning system further comprises a first three-way reversing valve, a second three-way reversing valve, a third three-way reversing valve and a fourth three-way reversing valve.

[0015] The first port, the second port and the third port of the first three-way reversing valve are respectively connected to the first port of the first outdoor heat exchanger, the second port of the indoor heat exchanger and the second port of the second three-way reversing valve;

[0016] The first interface, the second interface and the third interface of the second three-way reversing valve are respectively connected to the first return port of the dual return air compressor, the third interface of the first three-way reversing valve and the third interface of the first four-way reversing valve;

[0017] The first port, the second port, and the third port of the third three-way reversing valve are respectively connected to the second port of the fourth three-way reversing valve, the second port of the indoor heat exchanger, and the first port of the second outdoor heat exchanger;

[0018] The first port, the second port and the third port of the fourth three-way reversing valve are respectively connected to the second port of the second four-way reversing valve, the first port of the third three-way reversing valve and the first port of the indoor heat exchanger.

[0019] When adopting the above technical solution, the switching of the heating mode and the defrost mode of the two outdoor heat exchangers can be completed by switching and coordinating multiple four-way reversing valves and multiple three-way reversing valves, further ensuring uninterrupted heating and preventing the indoor temperature from dropping.

[0020] In the preferred technical solution of the above air-conditioning system,

[0021] The air conditioning system further includes a first throttling device and a second throttling device, wherein two ends of the first throttling device are respectively communicated with the second port of the indoor heat exchanger and the first port of the first outdoor heat exchanger, and two ends of the second throttling device are respectively communicated with the second port of the indoor heat exchanger and the first port of the second outdoor heat exchanger, and / or

[0022] The air-conditioning system also includes a first liquid reservoir and a second liquid reservoir, wherein two ends of the first liquid reservoir are respectively connected to the second port of the first outdoor heat exchanger and the first return air port of the dual return air compressor, and two ends of the second liquid reservoir are respectively connected to the second port of the second outdoor heat exchanger and the second return air port of the dual return air compressor.

[0023] The present application also provides a defrost control method for an air-conditioning system, wherein the air-conditioning system includes a double-return air compressor, an indoor heat exchanger, a first outdoor heat exchanger, and a second outdoor heat exchanger.

[0024] The exhaust port of the dual return air compressor is in communication with the first port of the indoor heat exchanger;

[0025] The second port of the indoor heat exchanger is communicated with the first port of the first outdoor heat exchanger and the first port of the second outdoor heat exchanger respectively;

[0026] The second port of the first outdoor heat exchanger and the second port of the second outdoor heat exchanger are respectively connected to the first return air port and the second return air port of the dual return air compressor;

[0027] Wherein, the double return air compressor forms a first defrost circuit and a second defrost circuit with the first outdoor heat exchanger and the second outdoor heat exchanger respectively;

[0028] The defrost control method comprises:

[0029] Acquire the dew point temperature, the coil temperature of the first outdoor heat exchanger, and the coil temperature of the second outdoor heat exchanger;

[0030] respectively comparing the coil temperature of the first outdoor heat exchanger and the coil temperature of the second outdoor heat exchanger with the dew point temperature;

[0031] According to the comparison result, the first outdoor heat exchanger and / or the second outdoor heat exchanger is selectively defrosted.

[0032] When adopting the above technical solution, by comparing the respective coil temperatures with the dew point temperatures, it is possible to more accurately determine whether the first outdoor heat exchanger and the second outdoor heat exchanger are frosted, and the first defrost circuit and the second defrost circuit can respectively complete defrosting of the first outdoor heat exchanger and the second outdoor heat exchanger. In the case of defrosting, the refrigerant will not flow into the indoor heat exchanger after releasing heat in the first outdoor heat exchanger or the second outdoor heat exchanger, thereby ensuring that the indoor temperature will not drop.

[0033] In the preferred technical solution of the above-mentioned defrost control method, the defrost control method further comprises:

[0034] Get the external ambient temperature;

[0035] Determining the dew point temperature according to a preset fitting formula;

[0036] The fitting formula is:

[0037] Tes=C×Tao-α

[0038] Among them, Tes is the dew point temperature, C is the temperature coefficient, Tao is the external ambient temperature, and α is the correction amount.

[0039] In the preferred technical solution of the above-mentioned defrost control method,

[0040] The selectively defrosting the first outdoor heat exchanger and / or the second outdoor heat exchanger according to the comparison result further includes:

[0041] According to the comparison result, the first outdoor heat exchanger and / or the second outdoor heat exchanger is selectively defrosted through the corresponding defrost circuit.

[0042] In the preferred technical solution of the above-mentioned defrost control method, selectively performing a defrost operation on the first outdoor heat exchanger and / or the second outdoor heat exchanger according to the comparison result further includes:

[0043] When the coil temperature of the first outdoor heat exchanger or the coil temperature of the second outdoor heat exchanger is less than or equal to the dew point temperature, performing a defrosting operation on the first outdoor heat exchanger or the second outdoor heat exchanger accordingly;

[0044] When the coil temperature of the first outdoor heat exchanger or the coil temperature of the second outdoor heat exchanger is less than or equal to the dew point temperature, the first outdoor heat exchanger and the second outdoor heat exchanger are defrosted in sequence.

[0045] When the above technical solution is adopted, when one outdoor heat exchanger is defrosting, the other outdoor heat exchanger can maintain heating operation, thereby further preventing the indoor temperature from dropping and providing users with a good user experience.

[0046] In the preferred technical solution of the above-mentioned defrost control method, the defrost control method further comprises:

[0047] Determine whether the outdoor heat exchanger in defrosting operation has completed defrosting;

[0048] After the outdoor heat exchanger completes defrosting, the outdoor heat exchanger is controlled accordingly to continue heating operation.

[0049] In the preferred technical solution of the above-mentioned defrost control method, the determination of whether the outdoor heat exchanger in the defrost operation has completed defrosting further includes:

[0050] comparing the coil temperature of the outdoor heat exchanger with a first preset temperature threshold and a second preset temperature threshold respectively;

[0051] When the coil temperature is greater than or equal to the first preset temperature threshold and continues for a first preset time, or when the coil temperature is greater than or equal to the second preset temperature threshold and continues for a second preset time, it is determined that defrosting is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The air conditioning system and the defrost control method thereof of the present application are described below with reference to the accompanying drawings. In the attached figure:

[0053] Figure 1 A schematic diagram of the air conditioning system of this application;

[0054] Figure 2 A schematic diagram of an air conditioning system when the first outdoor heat exchanger of the present application is defrosted;

[0055] Figure 3 A schematic diagram of the air conditioning system when the second outdoor heat exchanger of the present application is defrosted;

[0056] Figure 4 This is a flow chart of the main steps of a defrost control method for an air-conditioning system according to an embodiment of the present application.

[0057] Reference Signs List

[0058] 10. Double return air compressor;

[0059] 20. Indoor heat exchanger;

[0060] 31. First outdoor heat exchanger; 32. Second outdoor heat exchanger;

[0061] 41, first four-way reversing valve; 411, first port; 412, second port; 413, third port; 414, fourth port;

[0062] 42, second four-way reversing valve; 421, first interface; 422, second interface; 423, third interface; 424, fourth interface;

[0063] 51, first three-way reversing valve; 511, first interface; 512, second interface; 513, third interface;

[0064] 52, second three-way reversing valve; 521, first interface; 522, second interface; 523, third interface;

[0065] 53, third three-way reversing valve; 531, first interface; 532, second interface; 533, third interface;

[0066] 54, fourth three-way reversing valve; 541, first interface; 542, second interface; 543, third interface;

[0067] 61. First throttling device; 62. Second throttling device;

[0068] 71. First liquid reservoir; 72. Second liquid reservoir;

[0069] 81. First temperature sensor; 82. Second temperature sensor. DETAILED DESCRIPTION

[0070] The preferred embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and are not intended to limit the scope of protection of the present application. For example, although the drawings show that multiple three-way reversing valves are used to coordinate and realize the switching between the heating mode and the defrost mode, this setting is not static, and those skilled in the art can make adjustments to it as needed to adapt to specific applications. For example, two coordinated three-way reversing valves are replaced with a four-way reversing valve, or the three-way reversing valve is replaced with multiple solenoid valves.

[0071] It should be noted that, in the description of this application, the terms "upper", "lower", "left", "right", "inside", "outside", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, "multiple" refers to at least two.

[0072] Furthermore, it should be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0073] As described in the background technology, during the winter heating process of the heat pump air conditioner, the high-temperature and high-pressure refrigerant is discharged from the compressor and enters the indoor heat exchanger to release heat, and then absorbs heat through the outdoor heat exchanger. At this time, the outdoor heat exchanger serves as the evaporator on the low-pressure side, and the water molecules in the humid air will precipitate and freeze on the surface of the outdoor heat exchanger. As the temperature continues to drop, the frost or ice on the surface of the heat exchanger becomes thicker and thicker, affecting the air volume of the outdoor heat exchanger, which in turn causes the temperature to drop, forming a vicious circle, seriously affecting the indoor heating air outlet temperature and effect experience.

[0074] To ensure the heating effect of the heat pump air conditioner, the outdoor heat exchanger is usually defrosted. However, in the existing technology, the temperature of the outdoor heat exchanger is generally increased by controlling the air conditioning cooling, thereby melting the ice and frost on the surface of the outdoor heat exchanger. However, this defrosting method will cause the indoor temperature to drop, thereby affecting the user experience.

[0075] In order to solve the problem of lowering indoor temperature during the defrosting process in existing air-conditioning systems, the present application provides an air-conditioning system, which includes a dual-return air compressor, an indoor heat exchanger, a first outdoor heat exchanger and a second outdoor heat exchanger. The exhaust port of the dual-return air compressor is connected to the first port of the indoor heat exchanger; the second port of the indoor heat exchanger is respectively connected to the first port of the first outdoor heat exchanger and the first port of the second outdoor heat exchanger; the second port of the first outdoor heat exchanger and the second port of the second outdoor heat exchanger are respectively connected to the first return air port and the second return air port of the dual-return air compressor; wherein, the first defrost circuit and the second defrost circuit are formed between the dual-return air compressor and the first outdoor heat exchanger and the second outdoor heat exchanger, respectively.

[0076] When the above-mentioned technical solution is adopted, the first outdoor heat exchanger and the second outdoor heat exchanger can be defrosted respectively through the first defrost circuit and the second defrost circuit, and in the case of defrosting, the refrigerant will not flow into the indoor heat exchanger after releasing heat in the first outdoor heat exchanger or the second outdoor heat exchanger, thereby ensuring that the indoor temperature will not drop.

[0077] Refer to the following Figures 1 to 3 , the air conditioning system of this application is described. Among them, Figure 1 A schematic diagram of the air conditioning system of this application; Figure 2A schematic diagram of an air conditioning system when the first outdoor heat exchanger of the present application is defrosted; Figure 3 This is a schematic diagram of the air-conditioning system when the second outdoor heat exchanger of the present application is defrosted.

[0078] like Figures 1 to 3 As shown, in a preferred embodiment, the air conditioning system includes a dual-return air compressor 10, an indoor heat exchanger 20, a first outdoor heat exchanger 31, a second outdoor heat exchanger 32, a first four-way reversing valve 41, a second four-way reversing valve 42, a first three-way reversing valve 51, a second three-way reversing valve 52, a third three-way reversing valve 53, a fourth three-way reversing valve 54, a first throttling device 61, a second throttling device 62, a first liquid reservoir 71, and a second liquid reservoir 72. A first temperature sensor 81 and a second temperature sensor 82 are provided on the first outdoor heat exchanger 31 and the second outdoor heat exchanger 32, respectively. The dual-return air compressor 10 forms a first defrost circuit and a second defrost circuit with the first outdoor heat exchanger 31 and the second outdoor heat exchanger 32, respectively.

[0079] The exhaust port of the dual-return air compressor 10 is connected to the first port of the indoor heat exchanger 20 (the left port of the indoor heat exchanger 20 in the figure), and the second port of the indoor heat exchanger 20 (the right port of the indoor heat exchanger 20 in the figure) is connected to the first port of the first outdoor heat exchanger 31 and the first port of the second outdoor heat exchanger 32, respectively. The second port of the first outdoor heat exchanger 31 and the second port of the second outdoor heat exchanger 32 are respectively connected to the first return air port and the second return air port of the dual-return air compressor 10. The dual-return air compressor 10 of the present application has two return air ports, and the pressure and temperature of the two return air ports are relatively independent, which facilitates the adjustment of the temperature of the two outdoor heat exchangers.

[0080] The first port 411, second port 412, third port 413, and fourth port 414 of the first four-way reversing valve 41 are respectively in communication with the exhaust port of the dual return air compressor 10, the first port of the indoor heat exchanger 20, the first return air port of the dual return air compressor 10, and the second port of the first outdoor heat exchanger 31. The first port 421, second port 422, third port 423, and fourth port 424 of the second four-way reversing valve 42 are respectively in communication with the exhaust port of the dual return air compressor 10, the first port of the indoor heat exchanger 20, the second return air port of the dual return air compressor 10, and the second port of the second outdoor heat exchanger 32.

[0081] The first port 511, second port 512, and third port 513 of the first three-way reversing valve 51 are respectively connected to the first port of the first outdoor heat exchanger 31, the second port of the indoor heat exchanger 20, and the second port 522 of the second three-way reversing valve 52. The first port 521, second port 522, and third port 523 of the second three-way reversing valve 52 are respectively connected to the first return port of the dual return compressor 10, the third port 513 of the first three-way reversing valve 51, and the third port 413 of the first four-way reversing valve 41. The first port 531, second port 532, and third port 533 of the third three-way reversing valve 53 are respectively connected to the second port 542 of the fourth three-way reversing valve 54, the second port of the indoor heat exchanger 20, and the first port of the second outdoor heat exchanger 32. The first port 541 , the second port 542 and the third port 543 of the fourth three-way reversing valve 54 are respectively connected to the second port 522 of the second four-way reversing valve 52 , the first port 531 of the third three-way reversing valve 53 and the first port of the indoor heat exchanger 20 .

[0082] The two ends of the first throttling device 61 are respectively connected to the first port 511 of the first three-way reversing valve 51 and the first port of the first outdoor heat exchanger 31. The two ends of the second throttling device 62 are respectively connected to the third port 533 of the third three-way reversing valve 53 and the first port of the second outdoor heat exchanger 32. Preferably, both the first throttling device 61 and the second throttling device 62 are configured as electronic expansion valves. The two ends of the first liquid reservoir 71 are respectively connected to the first port 521 of the second three-way reversing valve 52 and the first return port of the dual-return compressor 10. The two ends of the second liquid reservoir 72 are respectively connected to the third port 423 of the second four-way reversing valve 42 and the second return port of the dual-return compressor 10.

[0083] In this embodiment, the first defrost circuit is composed of a double return air compressor 10, a first four-way reversing valve 41, a first outdoor heat exchanger 31, a first throttling device 61, a first three-way reversing valve 51, a second three-way reversing valve 52 and a first liquid reservoir 71, and the second defrost circuit is composed of a double return air compressor 10, a second four-way reversing valve 42, a second outdoor heat exchanger 32, a second throttling device 62, a third three-way reversing valve 53, a fourth three-way reversing valve 54 and a second liquid reservoir 72.

[0084] like Figure 1As shown, when the first outdoor heat exchanger 31 and the second outdoor heat exchanger 32 are both in heating operation, the first interface 411 and the second interface 412 of the first four-way reversing valve 41 are connected, the third interface 413 and the fourth interface 414 are connected, the first interface 421 and the second interface 422 of the second four-way reversing valve 42 are connected, the third interface 423 and the fourth interface 424 are connected, the first interface 511 and the second interface 512 of the first three-way reversing valve 51 are connected, the first interface 521 and the third interface 523 of the second three-way reversing valve 52 are connected, the second interface 532 and the third interface 533 of the third three-way reversing valve 53 are connected, and the first interface 541 and the third interface 543 of the fourth three-way reversing valve 54 are connected. After the dual-return air compressor 10 compresses the refrigerant into a high-temperature and high-pressure gas, one path of the refrigerant first enters the indoor heat exchanger 20 to release heat through the first interface 411 and the second interface 412 of the first four-way reversing valve 41, and then flows through the second interface 512 and the first interface 511 of the first three-way reversing valve 51, the first throttling device 61, the first outdoor heat exchanger 31, the fourth interface 414 and the third interface 413 of the first four-way reversing valve 41, the third interface 523 and the first interface 521 of the second three-way reversing valve 52, and the first liquid reservoir 71 before returning to the dual-return air compressor 10. The other refrigerant flows in sequence through the first interface 421 and the second interface 422 of the second four-way reversing valve 42, the first interface 541 and the third interface 543 of the fourth three-way reversing valve 54, the indoor heat exchanger 20, the second interface 532 and the third interface 533 of the third three-way reversing valve 53, the second outdoor heat exchanger 32, the fourth interface 424 and the third interface 423 of the second four-way reversing valve 42, the second liquid reservoir 72, and then returns to the dual return air compressor 10.

[0085] like Figure 2 As shown, when the first outdoor heat exchanger 31 is defrosted and the second outdoor heat exchanger 32 is in heating operation, the first defrost circuit remains in a flow state. At this time, the first throttling device 61 is fully open, the first port 421 and the fourth port 424 of the first four-way reversing valve 41 are connected, the second port 412 and the third port 423 are connected, the first port 511 and the third port 513 of the first three-way reversing valve 51 are connected, and the first port 521 and the second port 522 of the second three-way reversing valve 52 are connected. After flowing out of the dual return air compressor 10, the refrigerant in the first defrost circuit first passes through the first port 421 and the fourth port 424 of the first four-way reversing valve 41 to enter the first outdoor heat exchanger 31 for heat release and defrosting, and then passes through the first throttling device 61, the first port 511 and the third port 513 of the first three-way reversing valve 51, the second port 522 and the first port 521 of the second three-way reversing valve 52, and the first liquid accumulator 71 before returning to the dual return air compressor 10.

[0086] like Figure 3As shown, when the first outdoor heat exchanger 31 is in heating operation and the second outdoor heat exchanger 32 is defrosted, the second defrost circuit remains in a passage state. At this time, the second throttling device 62 is fully open, the first interface 421 and the fourth interface 424 of the second four-way reversing valve 42 are connected, the second interface 422 and the third interface 423 are connected, the first interface 531 and the third interface 533 of the third three-way reversing valve 53 are connected, and the first interface 541 and the second interface 542 of the fourth three-way reversing valve 54 are connected. After flowing out of the dual-return air compressor 10, the refrigerant in the second defrost circuit first enters the second outdoor heat exchanger 32 through the first interface 421 and the fourth interface 424 of the second four-way reversing valve 42 to release heat and defrost, and then passes through the second throttling device 62, the third interface 533 and the first interface 531 of the third three-way reversing valve 53, the second interface 542 and the first interface 541 of the fourth three-way reversing valve 54, the second interface 422 and the third interface 423 of the second four-way reversing valve 42, and the second liquid reservoir 72 before returning to the dual-return air compressor 10.

[0087] Those skilled in the art will appreciate that, although the present embodiment utilizes the coordination of multiple four-way reversing valves and three-way reversing valves to achieve switching between the heating mode and the defrosting mode of the two outdoor heat exchangers, the specific configuration is not set in stone. In an alternative embodiment, taking the heating and defrosting of the first outdoor heat exchanger 31 as an example, the first three-way reversing valve 51 and the second three-way reversing valve 52 can be replaced with a third four-way reversing valve. In this case, the first port, the second port, the third port, and the fourth port of the third four-way reversing valve are respectively connected to the second port of the indoor heat exchanger 20, the third port 413 of the first four-way reversing valve 41, the first return port of the dual return air compressor 10, and the first port of the first outdoor heat exchanger 31. During heating operation of the first outdoor heat exchanger 31, the refrigerant flows out of the second port of the indoor heat exchanger 20 and passes through the first and fourth ports of the third four-way reversing valve, the first throttling device 61, the first outdoor heat exchanger 31, the fourth port 414 and the third port 413 of the first four-way reversing valve 41, the second and third ports of the third four-way reversing valve, and the first liquid reservoir 71 before returning to the dual-return compressor 10. During defrosting of the first outdoor heat exchanger 31, the refrigerant flows out of the first throttling device 61 and passes through the fourth and third ports of the third four-way reversing valve, the first liquid reservoir 71, and then returns to the dual-return compressor 10. Accordingly, the first four-way valve 41 or the second four-way valve 42 can be replaced with multiple interconnected three-way reversing valves, as long as the switching between heating and defrosting modes of the two outdoor heat exchangers can be achieved. This will not be elaborated here. Of course, the four-way and three-way reversing valves can also be omitted; in this case, the refrigerant flow direction can be controlled solely by multiple solenoid valves.

[0088] Those skilled in the art will also understand that the configuration of the first throttling device 61, the second throttling device 62, the first liquid reservoir 71, and the second liquid reservoir 72 is not fixed. In an alternative embodiment, the first throttling device 61 and the second throttling device 62 can be configured as capillary tubes, or a throttling device can be provided in the main flow path after the indoor heat exchanger 20. In another alternative embodiment, the first liquid reservoir 71 and the second liquid reservoir 72 can be configured as gas-liquid separators, or one or more of the first liquid reservoir 71 and the second liquid reservoir 72 can be omitted.

[0089] The present application also provides a defrost control method for an air conditioning system. Figures 1 to 4 The defrost control method of the air conditioning system of the present application is described, wherein: Figure 4 This is a flow chart of the main steps of a defrost control method for an air-conditioning system according to an embodiment of the present application.

[0090] like Figure 4 As shown, in one embodiment, the defrost control method includes:

[0091] S401, obtain the dew point temperature, the coil temperature of the first outdoor heat exchanger and the coil temperature of the second outdoor heat exchanger. The dew point temperature can be pre-set or obtained by calculation or reading a comparison table. Figure 1 For example, the coil temperature of the first outdoor heat exchanger 31 and the coil temperature of the second outdoor heat exchanger 32 can be obtained by the first temperature sensor 81 and the second temperature sensor 82 .

[0092] S402: Compare the coil temperature of the first outdoor heat exchanger and the coil temperature of the second outdoor heat exchanger with the dew point temperature. For example, the coil temperature of the first outdoor heat exchanger and the coil temperature of the second outdoor heat exchanger may be compared with the dew point temperature sequentially or simultaneously.

[0093] S403, based on the comparison result, selectively perform a defrost operation on the first outdoor heat exchanger and / or the second outdoor heat exchanger. For example, when the coil temperature of the first outdoor heat exchanger or the coil temperature of the second outdoor heat exchanger is less than or equal to the dew point temperature, the first outdoor heat exchanger or the second outdoor heat exchanger is defrosted accordingly; when the coil temperature of the first outdoor heat exchanger or the coil temperature of the second outdoor heat exchanger is both less than or equal to the dew point temperature, the first outdoor heat exchanger and the second outdoor heat exchanger are defrosted in sequence. Figure 1 For example, when the first outdoor heat exchanger 31 needs to be defrosted, the first defrost circuit remains in a passage state to defrost the first outdoor heat exchanger 31, and the second outdoor heat exchanger 32 maintains heating operation; when the second outdoor heat exchanger 32 is defrosted by the second defrost circuit, the first outdoor heat exchanger 31 maintains heating operation.

[0094] By comparing the respective coil temperatures with the dew point temperatures through the methods described in steps S401 to S403, it can be more accurately determined whether the first outdoor heat exchanger and the second outdoor heat exchanger are frosted, and the first defrost circuit and the second defrost circuit can respectively complete defrosting of the first outdoor heat exchanger and the second outdoor heat exchanger. In the case of defrosting, the refrigerant will not flow into the indoor heat exchanger after releasing heat in the first outdoor heat exchanger or the second outdoor heat exchanger, thereby ensuring that the indoor temperature will not drop.

[0095] Those skilled in the art will understand that, although in the present embodiment, when any one of the outdoor heat exchangers is defrosted, the other outdoor heat exchanger maintains heating operation, this is not necessary. In an alternative embodiment, the first outdoor heat exchanger and the second outdoor heat exchanger can be defrosted at the same time. At this time, since the first defrost circuit and the second defrost circuit do not include the indoor heat exchanger, it can also be ensured that the indoor temperature will not be lowered during the defrosting process. However, considering the continuous indoor heating, it is a better choice to defrost the first outdoor heat exchanger and the second outdoor heat exchanger in turn, and those skilled in the art can change the order of defrosting the two outdoor heat exchangers at their own discretion.

[0096] In some embodiments, the dew point temperature may be determined by the following steps:

[0097] Obtaining the external ambient temperature. For example, the external ambient temperature may be obtained from a temperature sensor built into the air conditioner, or may be obtained through an electronic device interacting with the air conditioner, or may be directly input by a user or input by a user through a terminal device interacting with the air conditioner.

[0098] According to the preset fitting formula, the dew point temperature is determined.

[0099] The fitting formula is: Tes = C × Tao - α

[0100] Where Tes is the dew point temperature, C is the temperature coefficient, Tao is the external ambient temperature, and α is the correction factor. This fitting formula can be derived experimentally or empirically. In this embodiment, α = 6. When Tao < 0°C, C = 0.8, and when Tao ≥ 0°C, C = 0.6. Of course, those skilled in the art can also modify the fitting formula or the specific settings of the values ​​as needed. Furthermore, the dew point temperature can also be obtained based on a comparison table, such as a comparison table between the outdoor ambient temperature and / or humidity and the dew point temperature.

[0101] In some embodiments, the defrost control method further comprises:

[0102] Determine whether the outdoor heat exchanger in defrosting operation has completed defrosting;

[0103] After the outdoor heat exchanger is defrosted, the outdoor heat exchanger is controlled accordingly to continue heating operation.

[0104] Furthermore, the following steps can be used to determine whether the outdoor heat exchanger in the defrosting operation has completed defrosting:

[0105] comparing the coil temperature of the outdoor heat exchanger with a first preset temperature threshold and a second preset temperature threshold respectively;

[0106] When the coil temperature is greater than or equal to a first preset temperature threshold and continues for a first preset time period, or when the coil temperature is greater than or equal to a second preset temperature threshold and continues for a second preset time period, it is determined that defrosting is completed.

[0107] In this embodiment, taking the first outdoor heat exchanger as an example, when the coil temperature of the first outdoor heat exchanger is greater than or equal to 5°C and lasts for 60 seconds, or when the coil temperature of the first outdoor heat exchanger is greater than or equal to 10°C and lasts for 20 seconds, it is determined that the first outdoor heat exchanger has completed defrosting and the first outdoor heat exchanger is controlled to resume heating operation.

[0108] Those skilled in the art will appreciate that the method for determining whether an outdoor heat exchanger in a defrosting operation has completed defrosting is not fixed. In an alternative embodiment, those skilled in the art may also change the preset temperature threshold or preset duration as needed. In another alternative embodiment, other methods may be used to determine whether the outdoor heat exchanger has completed defrosting, for example, by determining whether defrosting has been completed based on the duration of the defrosting operation on the outdoor heat exchanger.

[0109] It should be noted that although the various steps in the above embodiment are described in the above-mentioned order, those skilled in the art will understand that in order to achieve the effect of this embodiment, different steps do not have to be executed in such an order. They can be executed simultaneously (in parallel) or in a reverse order. These simple changes are within the scope of protection of this application.

[0110] Those skilled in the art will appreciate that although some embodiments described herein include certain features included in other embodiments but not other features, combinations of features from different embodiments are intended to be within the scope of this application and to form different embodiments. For example, in the claims of this application, any of the claimed embodiments may be used in any combination.

[0111] Thus far, the technical solutions of the present application have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is readily understood by those skilled in the art that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present application.

Claims

1. An air conditioning system, characterized in that: The air conditioning system includes a double return air compressor, an indoor heat exchanger, a first outdoor heat exchanger and a second outdoor heat exchanger. The exhaust port of the dual return air compressor is in communication with the first port of the indoor heat exchanger; The second port of the indoor heat exchanger is communicated with the first port of the first outdoor heat exchanger and the first port of the second outdoor heat exchanger respectively; The second port of the first outdoor heat exchanger and the second port of the second outdoor heat exchanger are respectively connected to the first return air port and the second return air port of the dual return air compressor; Wherein, the dual return air compressor forms a first defrost circuit and a second defrost circuit with the first outdoor heat exchanger and the second outdoor heat exchanger respectively.

2. The air conditioning system according to claim 1, characterized in that The air conditioning system further includes a first four-way reversing valve and a second four-way reversing valve. The first port, the second port, the third port and the fourth port of the first four-way reversing valve are respectively connected to the exhaust port of the double return air compressor, the first port of the indoor heat exchanger, the first return air port of the double return air compressor and the second port of the first outdoor heat exchanger; The first port, the second port, the third port and the fourth port of the second four-way reversing valve are respectively connected to the exhaust port of the double return air compressor, the first port of the indoor heat exchanger, the second return air port of the double return air compressor and the second port of the second outdoor heat exchanger.

3. The air conditioning system according to claim 2, characterized in that The air conditioning system further includes a first three-way reversing valve, a second three-way reversing valve, a third three-way reversing valve and a fourth three-way reversing valve. The first port, the second port and the third port of the first three-way reversing valve are respectively connected to the first port of the first outdoor heat exchanger, the second port of the indoor heat exchanger and the second port of the second three-way reversing valve; The first interface, the second interface and the third interface of the second three-way reversing valve are respectively connected to the first return port of the dual return air compressor, the third interface of the first three-way reversing valve and the third interface of the first four-way reversing valve; The first port, the second port, and the third port of the third three-way reversing valve are respectively connected to the second port of the fourth three-way reversing valve, the second port of the indoor heat exchanger, and the first port of the second outdoor heat exchanger; The first port, the second port and the third port of the fourth three-way reversing valve are respectively connected to the second port of the second four-way reversing valve, the first port of the third three-way reversing valve and the first port of the indoor heat exchanger.

4. The air conditioning system according to claim 1, characterized in that The air conditioning system further includes a first throttling device and a second throttling device, wherein two ends of the first throttling device are respectively communicated with the second port of the indoor heat exchanger and the first port of the first outdoor heat exchanger, and two ends of the second throttling device are respectively communicated with the second port of the indoor heat exchanger and the first port of the second outdoor heat exchanger, and / or The air-conditioning system also includes a first liquid reservoir and a second liquid reservoir, wherein two ends of the first liquid reservoir are respectively connected to the second port of the first outdoor heat exchanger and the first return air port of the dual return air compressor, and two ends of the second liquid reservoir are respectively connected to the second port of the second outdoor heat exchanger and the second return air port of the dual return air compressor.

5. A defrost control method for an air conditioning system, characterized in that: The air conditioning system includes a double return air compressor, an indoor heat exchanger, a first outdoor heat exchanger and a second outdoor heat exchanger. The exhaust port of the dual return air compressor is in communication with the first port of the indoor heat exchanger; The second port of the indoor heat exchanger is communicated with the first port of the first outdoor heat exchanger and the first port of the second outdoor heat exchanger respectively; The second port of the first outdoor heat exchanger and the second port of the second outdoor heat exchanger are respectively connected to the first return air port and the second return air port of the dual return air compressor; Wherein, the double return air compressor forms a first defrost circuit and a second defrost circuit with the first outdoor heat exchanger and the second outdoor heat exchanger respectively; The defrost control method comprises: Acquire the dew point temperature, the coil temperature of the first outdoor heat exchanger, and the coil temperature of the second outdoor heat exchanger; respectively comparing the coil temperature of the first outdoor heat exchanger and the coil temperature of the second outdoor heat exchanger with the dew point temperature; According to the comparison result, the first outdoor heat exchanger and / or the second outdoor heat exchanger is selectively defrosted.

6. The defrost control method according to claim 5, characterized in that: The defrost control method further includes: Get the external ambient temperature; Determining the dew point temperature according to a preset fitting formula; The fitting formula is: Tes=C×Tao-α Among them, Tes is the dew point temperature, C is the temperature coefficient, Tao is the external ambient temperature, and α is the correction amount.

7. The defrost control method according to claim 5, characterized in that: The selectively defrosting the first outdoor heat exchanger and / or the second outdoor heat exchanger according to the comparison result further includes: According to the comparison result, the first outdoor heat exchanger and / or the second outdoor heat exchanger is selectively defrosted through the corresponding defrost circuit.

8. The defrost control method according to claim 5, wherein: The selectively defrosting the first outdoor heat exchanger and / or the second outdoor heat exchanger according to the comparison result further includes: When the coil temperature of the first outdoor heat exchanger or the coil temperature of the second outdoor heat exchanger is less than or equal to the dew point temperature, performing a defrosting operation on the first outdoor heat exchanger or the second outdoor heat exchanger accordingly; When the coil temperature of the first outdoor heat exchanger or the coil temperature of the second outdoor heat exchanger is less than or equal to the dew point temperature, the first outdoor heat exchanger and the second outdoor heat exchanger are defrosted in sequence.

9. The defrost control method according to any one of claims 5 to 8, characterized in that: The defrost control method further includes: Determine whether the outdoor heat exchanger in defrosting operation has completed defrosting; After the outdoor heat exchanger completes defrosting, the outdoor heat exchanger is controlled accordingly to continue heating operation.

10. The defrost control method according to claim 9, characterized in that: The step of determining whether the outdoor heat exchanger in the defrosting operation has completed defrosting further includes: comparing the coil temperature of the outdoor heat exchanger with a first preset temperature threshold and a second preset temperature threshold respectively; When the coil temperature is greater than or equal to the first preset temperature threshold and continues for a first preset time, or when the coil temperature is greater than or equal to the second preset temperature threshold and continues for a second preset time, it is determined that defrosting is completed.

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