Distributed heat exchange three-pipeline air conditioner heat exchange pipeline and air conditioner system

Abstract

The application provides a distributed heat exchange three-pipeline air conditioner heat exchange pipeline and an air conditioner system, relates to the technical field of air conditioner equipment, and through splitting an outdoor unit heat exchanger into two independent heat exchangers and arranging a one-way valve and a refrigerant cutoff valve in a pipeline, the working path of a three-four-way valve is simulated; the system can control the conduction state between each end of the four-way valve, the conduction state of the electronic expansion valve and the conduction state of the refrigerant cutoff valve based on the working state of the air conditioner, so as to realize the heat exchange efficiency and effect of the three-four-way valve pipeline. Compared with the prior art, the circuit does not need to additionally arrange a four-way valve, and compared with the scheme of adding a four-way valve, the pipeline is rarely increased, the complexity of the heat exchange system is reduced, the system occupies a smaller space, and can be applied to a small air conditioner outdoor unit system.

Description

Technical Field

[0001] This invention relates to the field of air conditioning systems, specifically to a distributed heat exchange three-pipe air conditioning heat exchange pipeline and air conditioning system. Background Technology

[0002] Three-pipe heat recovery multi-split air conditioners are currently more common in the market with top-discharge models than side-discharge models. Compared to top-discharge models, side-discharge air conditioners have a significant disadvantage: much less space for system piping, making complex piping installations difficult. Currently, the commonly used three-pipe air conditioning systems for top-discharge models often use three or more four-way valves, resulting in complex piping connections. In top-discharge models, there is ample space for piping installation, while side-discharge multi-split models face space constraints. Whether it's a 10HP or 24HP side-discharge platform, the larger the system's horsepower, the larger the air conditioning unit's casing, but the larger the required four-way valve specifications also become. When using a single four-way valve, the space inside the indoor and outdoor units is often quite limited; a double four-way valve design is already the limit, and a triple four-way valve design is almost impossible to apply in indoor and outdoor unit systems. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide a distributed heat exchange three-pipe air conditioning heat exchange pipeline and air conditioning system, so as to realize a design scheme of three- or four-way valves within the limited space of the air conditioning indoor and outdoor units.

[0004] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0005] A distributed heat exchange three-pipe air conditioning heat exchange pipeline, further comprising:

[0006] The first four-way valve has its first end connected to the second end of the high-pressure pipe via a first one-way valve, its second end connected to the second end of the low-pressure pipe, its input end connected to the first end of the first four-way valve, and its output end connected to the second end of the high-pressure pipe.

[0007] The second four-way valve has its first end connected to the second end of the high-pressure pipe via a second check valve, its second end connected to the second end of the low-pressure pipe, its input end connected to the first end of the second four-way valve, and its output end connected to the second end of the high-pressure pipe.

[0008] The first outdoor unit heat exchanger has its first end connected to the second ends of the first four-way valve and the second four-way valve in sequence via a refrigerant shut-off valve and a third one-way valve. The first end of the first outdoor unit heat exchanger is also connected to the third end of the second four-way valve via a fourth one-way valve. The second end of the first outdoor unit heat exchanger is connected to the second end of the second outdoor unit heat exchanger. The input end of the third one-way valve is connected to the second ends of the first four-way valve and the second four-way valve. The input end of the fourth one-way valve is connected to the third end of the second four-way valve. The output end of the third one-way valve is connected to the refrigerant shut-off valve. The output end of the fourth one-way valve is connected to the first end of the first outdoor unit heat exchanger. The second end of the first outdoor unit heat exchanger is connected to the second end of the subcooling device.

[0009] The second outdoor unit heat exchanger has its first end connected to the third end of the first four-way valve, and its second end connected to the second end of the subcooling device.

[0010] A first compressor, wherein the first end of the first compressor is connected to the fourth end of the first four-way valve and the second four-way valve;

[0011] A gas-liquid separator, wherein the first end of the gas-liquid separator is connected to the first end of the first outdoor unit heat exchanger, and the second end of the gas-liquid separator is connected to the second end of the first compressor;

[0012] A subcooling device, wherein a first end of the subcooling device is connected to a second end of a liquid pipe;

[0013] A first electronic expansion valve is disposed between the second end of the first outdoor unit heat exchanger and the second end of the subcooling device;

[0014] The second electronic expansion valve is located between the second end of the second outdoor unit heat exchanger and the second end of the subcooling device.

[0015] Optionally, the above-mentioned distributed heat exchange three-pipe air conditioning heat exchange pipeline also includes:

[0016] The first three-way valve has its first end connected to the first end of the low-pressure pipe, its second end connected to the first end of the high-pressure pipe, and its third end connected to the first end of the first indoor unit.

[0017] A first indoor unit, wherein the second end of the first indoor unit is connected to the first end of the liquid pipe;

[0018] The second three-way valve has its first end connected to the first end of the low-pressure pipe, its second end connected to the first end of the high-pressure pipe, and its third end connected to the first end of the second indoor unit.

[0019] The second indoor unit has its second end connected to the first end of the liquid pipe.

[0020] Optionally, the above-mentioned distributed heat exchange three-pipe air conditioning heat exchange pipeline also includes:

[0021] The controller is used to obtain the actual demand heat compensation percentage and control the conduction state of the first four-way valve, the second four-way valve, the first three-way valve, the second three-way valve and the refrigerant shut-off valve based on the actual demand heat compensation percentage.

[0022] Optionally, in the above-mentioned distributed heat exchange three-pipe air conditioning heat exchange pipeline, controlling the conduction state of the first four-way valve, the second four-way valve, the first three-way valve, the second three-way valve, the refrigerant shut-off valve, the first electronic expansion valve, and the second electronic expansion valve based on the actual demand heat compensation percentage includes:

[0023] Determine the target range to which the actual required heat compensation percentage belongs, obtain the target conduction state corresponding to the target range, and control the conduction state of the first four-way valve, the second four-way valve, the first three-way valve, the second three-way valve, the refrigerant shut-off valve, the first electronic expansion valve, and the second electronic expansion valve based on the target conduction state.

[0024] Optionally, in the above-mentioned distributed heat exchange three-pipe air conditioning heat exchange pipeline, when the target range to which the actual demand heat compensation percentage belongs is the first target range, the target conduction state is as follows: the first end and the fourth end of the first four-way valve are connected, the second end and the third end of the first four-way valve are connected, the first end and the fourth end of the second four-way valve are connected, the second end and the third end of the first three-way valve are connected, the second end and the third end of the second three-way valve are connected, the refrigerant shut-off valve is in the conduction state, and the first electronic expansion valve and the second electronic expansion valve are open;

[0025] When the target range to which the actual demand heat compensation percentage belongs is the second target range, the target conduction state is as follows: the first end and the fourth end of the first four-way valve are connected, the second end and the third end of the first four-way valve are connected, the first end and the fourth end of the second four-way valve are connected, the second end and the third end of the first three-way valve are connected, the first end and the third end of the second three-way valve are connected, the refrigerant shut-off valve is in the conduction state, and the first electronic expansion valve and the second electronic expansion valve are open;

[0026] When the target range to which the actual demand heat compensation percentage belongs is the third target range, the target conduction state is as follows: the first end and the fourth end of the first four-way valve are connected, the first end and the fourth end of the second four-way valve are connected, the second end and the third end of the first three-way valve are connected, the first end and the third end of the second three-way valve are connected, the refrigerant shut-off valve is in the conduction state, and the first electronic expansion valve and the second electronic expansion valve are open;

[0027] When the target range to which the actual demand heat compensation percentage belongs is the fourth target range, the target conduction state is as follows: the first end and the fourth end of the first four-way valve are connected, the first end and the fourth end of the second four-way valve are connected, the second end and the third end of the first three-way valve are connected, the first end and the third end of the second three-way valve are connected, the refrigerant shut-off valve is in the shut-off state, and the first electronic expansion valve and the second electronic expansion valve are closed.

[0028] When the target range to which the actual demand heat compensation percentage belongs is the fifth target range, the target conduction state is as follows: the first end and the fourth end of the first four-way valve are connected, the third end and the fourth end of the second four-way valve are connected, the second end and the third end of the first three-way valve are connected, the first end and the third end of the second three-way valve are connected, the refrigerant shut-off valve is in the shut-off state, the first electronic expansion valve is closed, and the second electronic expansion valve is open.

[0029] When the target range to which the actual demand heat compensation percentage belongs is the sixth target range, the target conduction state is as follows: the third and fourth ends of the first four-way valve are connected, the third and fourth ends of the second four-way valve are connected, the second and third ends of the first three-way valve are connected, the first and third ends of the second three-way valve are connected, the refrigerant shut-off valve is in the shut-off state, the first electronic expansion valve is open, and the second electronic expansion valve is closed.

[0030] When the target range to which the actual demand heat compensation percentage belongs is the seventh target range, the target conduction state is as follows: the third and fourth ends of the first four-way valve are connected, the third and fourth ends of the second four-way valve are connected, the first and third ends of the first three-way valve are connected, the first and third ends of the second three-way valve are connected, the refrigerant shut-off valve is in the shut-off state, and the first and second electronic expansion valves are open.

[0031] Optionally, in the above-mentioned distributed heat exchange three-pipe air conditioning heat exchange pipeline, the controller is further used for:

[0032] When the first defrost command is detected, the system responds to the first defrost command, which controls: the first and fourth ends of the first four-way valve are connected, the second and third ends of the first four-way valve are connected, the third and fourth ends of the second four-way valve are connected, the second and third ends of the first three-way valve are connected, the second and third ends of the second three-way valve are connected, the refrigerant shut-off valve is in the shut-off state, and the first and second electronic expansion valves are open.

[0033] When a second defrost command is detected, the system responds to the second defrost command, which controls: the third and fourth ends of the first four-way valve are connected; the first and fourth ends of the second four-way valve are connected; the second and third ends of the first three-way valve are connected; the second and third ends of the second three-way valve are connected; the refrigerant shut-off valve is in the on state; and the first and second electronic expansion valves are open.

[0034] Optionally, in the above-mentioned distributed heat exchange three-pipe air conditioning heat exchange pipeline, the controller is further used for:

[0035] When a third defrost command is detected, the system responds to the third defrost command, which controls: the first and fourth ends of the first four-way valve are connected, the second and third ends of the first four-way valve are connected, the third and fourth ends of the second four-way valve are connected, the second and third ends of the first three-way valve are connected, the first and third ends of the second three-way valve are connected, the refrigerant shut-off valve is in the shut-off state, and the first and second electronic expansion valves are open.

[0036] When a fourth defrost command is detected, the system responds to the fourth defrost command, which controls: the third and fourth ends of the first four-way valve to be connected; the first and fourth ends of the second four-way valve to be connected; the second and third ends of the first three-way valve to be connected; the first and third ends of the second three-way valve to be connected; the refrigerant shut-off valve to be in the connected state; and the first and second electronic expansion valves to be opened.

[0037] Optionally, the above-mentioned distributed heat exchange three-pipe air conditioning heat exchange pipeline also includes: a third four-way valve and a third outdoor unit heat exchanger;

[0038] The third four-way valve has the following configuration: its first end is connected to the second end of the high-pressure pipe via a fifth one-way valve; its second end is connected to the second end of the low-pressure pipe; its third end is connected to the first end of the third outdoor unit heat exchanger via a sixth one-way valve; its fourth end is connected to the fourth ends of both the first and second four-way valves; its input end is connected to the first end of the third four-way valve; its output end is connected to the second end of the high-pressure pipe; its output end is connected to the first end of the third outdoor unit heat exchanger; and its input end is connected to the third end of the third four-way valve.

[0039] The third outdoor unit heat exchanger is connected to the second end of the subcooling device via a third electronic expansion valve.

[0040] Optionally, the above-mentioned distributed heat exchange three-pipe air conditioning heat exchange pipeline also includes:

[0041] The second compressor serves as a backup for the first compressor.

[0042] An air conditioning system comprising the distributed heat exchange three-pipe air conditioning heat exchange pipeline as described in any one of the above.

[0043] Optionally, the air conditioning system described above includes N distributed heat exchange three-pipe air conditioning heat exchange pipelines, and the N distributed heat exchange three-pipe air conditioning heat exchange pipelines share the first indoor unit and the second indoor unit, where N is a positive integer not less than 2.

[0044] Based on the above technical solution, the solution provided in this embodiment of the invention, by splitting the outdoor unit heat exchanger into two independent heat exchangers and setting additional one-way valves and refrigerant shut-off valves in the pipeline, simulates the working path of a three-way or four-way valve. The system can control the conduction state between each end of the four-way valve, the conduction state of the electronic expansion valve, and the conduction state of the refrigerant shut-off valve based on the working state of the air conditioner, thereby achieving heat exchange efficiency and effect similar to that of a three-way or four-way valve pipeline. Moreover, compared with existing solutions, the above circuit does not require additional four-way valves, and the amount of additional pipeline is minimal compared to solutions that add a four-way valve, reducing the complexity of the heat exchange system, and the system occupies less space, making it suitable for small-sized air conditioner outdoor unit systems. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of the structure of the distributed heat exchange three-pipe air conditioning heat exchange pipeline disclosed in the embodiments of this application;

[0047] Figures 2-12 This is a schematic diagram of the refrigerant path in various operating modes of the distributed heat exchange three-pipe air conditioning heat exchange pipeline disclosed in the embodiments of this application;

[0048] Figure 13 This describes the connection status of various components in the two backup compressor systems disclosed in the embodiments of this application;

[0049] Figure 14 This is a schematic diagram of the structure of a distributed heat exchange three-pipe air conditioning heat exchange pipeline disclosed in another embodiment of this application;

[0050] Figure 15 This is a schematic diagram of the structure of an air conditioning system with multiple distributed heat exchange three-pipe air conditioning heat exchange pipelines disclosed in an embodiment of this application. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] This application, by replacing another four-way valve and its corresponding piping with a check valve, refrigerant on / off valve, and corresponding additional piping in a dual four-way valve system, greatly saves the space occupied by the pipe group system in the air conditioning system, making it possible to apply heat recovery air conditioning technology in small-space multi-split products.

[0053] See Figure 1 This application discloses a distributed heat exchange three-pipe air conditioning heat exchange pipeline, which includes: a first four-way valve 4WV1, a second four-way valve 4WV2, a first outdoor unit heat exchanger OC1, a second outdoor unit heat exchanger OC2, a gas-liquid separator ACC, a subcooling device SC, a first electronic expansion valve Leva1, and a second electronic expansion valve Leva2.

[0054] The first end E of the first four-way valve 4WV1 is connected to the second end of the high-pressure pipe Hp through the first one-way valve D1. The second end S of the first four-way valve 4WV1 is connected to the second end of the low-pressure pipe Lp. The third end C of the first four-way valve 4WV1 is connected to the first end of the second outdoor heat exchanger OC2. The fourth end D of the first four-way valve 4WV1 is connected to the first end of the first compressor TD1 through the first oil separator OS1. The input end of the first one-way valve D1 is connected to the first end E of the first four-way valve 4WV1. The output end of the first one-way valve D1 is connected to the second end of the high-pressure pipe Hp.

[0055] The first end E of the second four-way valve 4WV2 is connected to the second end of the high-pressure pipe Hp through the second one-way valve D2; the second end S of the second four-way valve 4WV2 is connected to the second end of the low-pressure pipe Lp; the third end C of the second four-way valve 4WV2 is connected to the first end of the first outdoor unit heat exchanger OC1; the fourth end D of the second four-way valve 4WV2 is connected to the first end E of the first four-way valve 4WV1; the input end of the second one-way valve D2 is connected to the first end E of the second four-way valve 4WV2; and the output end of the second one-way valve D2 is connected to the second end of the high-pressure pipe Hp.

[0056] The first end of the first outdoor unit heat exchanger OC1 is connected to the low-pressure pipe Lp via a refrigerant shut-off valve SV2 and a third one-way valve D3, which is also connected to the second end of the first four-way valve 4WV1 and the second four-way valve 4WV2. The first end of the first outdoor unit heat exchanger OC1 is also connected to the third end C of the second four-way valve 4WV2 via a fourth one-way valve D4. The second end of the first outdoor unit heat exchanger OC1 is connected to the second end of the subcooling device SC via a first electronic expansion valve Leva1. The input end of the third one-way valve D3 is connected to the second end S of the first four-way valve 4WV1 and the second four-way valve 4WV2. The input end of the fourth one-way valve D4 is connected to the third end C of the second four-way valve 4WV2. The output end of the third one-way valve D3 is connected to the refrigerant shut-off valve SV2. The output end of the fourth one-way valve D4 is connected to the first end of the first outdoor unit heat exchanger OC1. The second end of the first outdoor unit heat exchanger OC1 is connected to the second end of the subcooling device SC.

[0057] The first end of the second outdoor unit heat exchanger OC2 is connected to the third end of the first four-way valve 4WV1, and the second end of the second outdoor unit heat exchanger OC2 is connected to the second end of the subcooling device SC through the second electronic expansion valve Leva2.

[0058] The first end of the first compressor TD1 is connected to the fourth end of the first four-way valve 4WV1, the fourth end D of the second four-way valve 4WV2, and the first end of the gas-liquid separator ACC through the first oil separator OS1. The second end of the first compressor TD1 is also connected to the return end of the first oil separator OS2 through the first capillary tube M1 (compressor tube).

[0059] The first end of the gas-liquid separator ACC is connected to the first end of the first outdoor unit heat exchanger via the refrigerant shut-off valve SV2. The first end of the gas-liquid separator ACC is also connected to the fourth end of the first four-way valve 4WV1 via the refrigerant shut-off valve SV1. The first end of the gas-liquid separator ACC is also connected to the liquid pipe via the refrigerant shut-off valve SV3 and the third electronic expansion valve Levab in sequence. The pipeline connecting the first end of the gas-liquid separator ACC and the liquid pipe passes through the subcooling device SC. The second end of the gas-liquid separator ACC is connected to the second end of the first compressor TD1. The first end of the gas-liquid separator ACC is also connected to the third end of the first compressor via the refrigerant shut-off valve SV3 and the refrigerant shut-off valve SV7 in sequence.

[0060] The first end of the subcooling device SC is connected to the second end of the liquid pipe. The second end of the subcooling device SC is connected to the second end of the first outdoor heat exchanger OC1 and the second end of the second outdoor heat exchanger OC2, respectively. The second end of the subcooling device SC is also connected to the first end of the gas-liquid separator ACC through the unloading valve RV.

[0061] The first electronic expansion valve Leva1 is located between the second end of the first outdoor unit heat exchanger OC1 and the second end of the subcooling device SC; the second electronic expansion valve Leva2 is located between the second end of the second outdoor unit heat exchanger OC2 and the second end of the subcooling device SC.

[0062] When using the aforementioned distributed heat exchange three-pipe air conditioning heat exchange pipeline, the system can control the conduction status of each end of the four-way valve, the conduction status of the electronic expansion valve, and the conduction status of the refrigerant shut-off valve based on the operating status of the air conditioner, thereby achieving heat exchange efficiency and effect similar to a three- or four-way valve pipeline. Furthermore, compared to existing solutions, the above circuit eliminates the need for an additional four-way valve, and requires fewer additional pipelines compared to solutions that add a four-way valve, reducing the complexity of the heat exchange system. The system also occupies less space and is suitable for smaller air conditioning outdoor unit systems.

[0063] The distributed heat exchange three-pipe air conditioning heat exchange pipeline in the above embodiments of this application can be integrated into the outdoor unit. The high-pressure pipe Hp and the low-pressure pipe Lp can be connected to the indoor unit through a three-way valve. The three-way valve can be integrated into the outdoor unit and the indoor unit, or it can be set up independently of the outdoor unit and the indoor unit. The air conditioning heat exchange pipeline can include a three-way valve. The first end A of the three-way valve is connected to the first end of the low-pressure pipe Lp, the second end B of the three-way valve is connected to the first end of the high-pressure pipe Hp, and the third end C of the three-way valve is connected to the first end of the indoor unit. The other end of the indoor unit is connected to the liquid pipe through an electronic expansion valve. The number of three-way valves corresponds one-to-one with the number of indoor units. For example, see [link to relevant documentation]. Figure 1 When the air conditioning system includes two indoor units (a first indoor unit and a second indoor unit), the three-way valve includes a first three-way valve 3wv1 and a second three-way valve 3wv2. The first end A of the first three-way valve 3wv1 and the second three-way valve 3wv2 is connected to the first end of the low-pressure pipe Lp. The second end of the first three-way valve 3wv1 and the second three-way valve 3wv2 is connected to the first end of the high-pressure pipe Hp. The third end of the first three-way valve 3wv1 is connected to the first end of the first indoor unit (which can be a heating indoor unit). The third end of the second three-way valve 3wv2 is connected to the first end of the second indoor unit (which can be a cooling indoor unit). The second ends of the first indoor unit and the second indoor unit are connected to the liquid pipe. The path switching of the cooling medium is realized through the conduction state between the three ports of the first three-way valve 3wv1 and the second three-way valve 3wv2.

[0064] In this embodiment, the conduction states of the four-way valve, three-way valve, refrigerant shut-off valve, and electronic expansion valve in the distributed heat exchange three-pipe air conditioning heat exchange pipeline can be controlled by a controller. The controller is used to obtain the actual required heat compensation percentage and, based on this percentage, controls the conduction states of the first four-way valve 4WV1, the second four-way valve 4WV2, the first three-way valve 3WV1, the second three-way valve 3WV2, each electronic expansion valve, and each refrigerant shut-off valve, thereby enabling the distributed heat exchange three-pipe air conditioning heat exchange pipeline to switch between various modes. Specifically, in this solution, the selection of the operating mode of the distributed heat exchange three-pipe air conditioning heat exchange pipeline depends on the magnitude of the actual required heat compensation percentage Qw. Different values ​​of Qw result in different operating modes for the distributed heat exchange three-pipe air conditioning heat exchange pipeline, and the operating mode of the distributed heat exchange three-pipe air conditioning heat exchange pipeline is determined by the conduction states of the aforementioned four-way valve, three-way valve, electronic expansion valve, and refrigerant shut-off valve. Where Qw = k1 × Qc - k2 × Qh; Qc is the indoor unit's cooling output percentage; Qh is the indoor unit's heating output percentage; K1 is the cooling compensation coefficient; and K2 is the heating compensation coefficient. The values ​​of K1 and K2 can be adjusted according to usage requirements. The following table, assuming K1 = K2 = 1, shows the actual load requirements of the outdoor unit under different cooling and heating loads of the indoor unit:

[0065]

[0066] Table 1

[0067] In this application, after obtaining the indoor unit's cooling output percentage Qc and heating output percentage Qh, the controller can calculate the actual demand heat compensation percentage Qw based on the formula Qw=k1×Qc-k2×Qh. Then, based on the target range to which the actual demand heat compensation percentage Qw belongs, the controller determines the operating mode of the distributed heat exchange three-pipe air conditioning heat exchange pipeline (different target ranges correspond to different operating modes). The operating mode of the distributed heat exchange three-pipe air conditioning heat exchange pipeline is determined by the first four-way valve 4WV1, the second four-way valve 4WV2, the first three-way valve 3wv1, the second three-way valve 3wv2, and the refrigerant shut-off valve. In addition to controlling the conduction state of each electronic expansion valve, the target conduction state of the first four-way valve 4WV1, the second four-way valve 4WV2, the first three-way valve 3WV1, the second three-way valve 3WV2, the refrigerant shut-off valve, and each electronic expansion valve is different in different working modes of the distributed heat exchange three-pipe air conditioning heat exchange pipeline. Therefore, controlling the working mode of the distributed heat exchange three-pipe air conditioning heat exchange pipeline is also controlling the first four-way valve 4WV1, the second four-way valve 4WV2, the first three-way valve 3WV1, the second three-way valve 3WV2, the refrigerant shut-off valve, and each electronic expansion valve to switch to the target conduction state that matches the target range.

[0068] In a specific embodiment of this application, the operating modes of the distributed heat exchange three-pipe air conditioning heat exchange pipeline include a first operating mode (indoor unit full heating operation mode), a second operating mode (indoor unit main heating operation mode with simultaneous cooling), a third operating mode (indoor unit cooling and heating balance mode with a bias towards heating), a fourth operating mode (indoor unit cooling and heating balance mode without bias), a fifth operating mode (indoor unit cooling and heating balance mode with a bias towards cooling), a sixth operating mode (indoor unit main cooling operation mode with simultaneous heating), and a seventh operating mode (indoor unit full cooling operation mode). The first target interval corresponding to the first operating mode is (0, Qa], the second target interval corresponding to the second operating mode is (Qa, Qb], the third target interval corresponding to the third operating mode is (Qb, Qc], the fourth target interval corresponding to the fourth operating mode is (Qc, Qd], the fifth target interval corresponding to the fifth operating mode is (Qd, Qe], the sixth target interval corresponding to the sixth operating mode is (Qe, Qf], and the seventh target interval corresponding to the seventh operating mode is (Qf, Qg).

[0069] When the target range to which the actual required heat compensation percentage belongs is the first target range (0, Qa), the target conduction state is as follows: the first and fourth ends of the first four-way valve 4WV1 are connected, the second and third ends of the first four-way valve 4WV1 are connected, the first and fourth ends of the second four-way valve 4WV2 are connected, the second and third ends of the first three-way valve 3WV1 are connected, the second and third ends of the second three-way valve 3WV2 are connected, the refrigerant shut-off valve is in the conducting state, and the first electronic expansion valve Leva1 and the second electronic expansion valve Leva2 are open; at this time, the flow path of the medium in the distributed heat exchange three-pipe air conditioning heat exchange pipeline is as follows: Figure 2 As shown in the various views provided in this application, thick red lines represent high-temperature, high-pressure gaseous refrigerant, thick green lines represent medium-temperature, high-pressure liquid refrigerant, thick blue lines represent low-temperature, low-pressure gaseous refrigerant, and arrows indicate the direction of refrigerant flow.

[0070] When the target range to which the actual required heat compensation percentage belongs is the second target range, the target conduction state is as follows: the first and fourth ends of the first four-way valve 4WV1 are connected, the second and third ends of the first four-way valve 4WV1 are connected, the first and fourth ends of the second four-way valve 4WV2 are connected, the second and third ends of the first three-way valve 3WV1 are connected, the first and third ends of the second three-way valve 3WV2 are connected, the refrigerant shut-off valve is in the conducting state, and the first electronic expansion valve Leva1 and the second electronic expansion valve Leva2 are open; at this time, the flow path of the medium in the distributed heat exchange three-pipe air conditioning heat exchange pipeline is as follows: Figure 3 As shown.

[0071] When the target range to which the actual required heat compensation percentage belongs is the third target range, the target conduction state is as follows: the first and fourth ends of the first four-way valve 4WV1 are connected, the first and fourth ends of the second four-way valve 4WV2 are connected, the second and third ends of the first three-way valve 3WV1 are connected, the first and third ends of the second three-way valve 3WV2 are connected, the refrigerant shut-off valve is in the conducting state, and the first electronic expansion valve Leva1 and the second electronic expansion valve Leva2 are open; at this time, the flow path of the medium in the distributed heat exchange three-pipe air conditioning heat exchange pipeline is as follows: Figure 4 As shown.

[0072] When the target range to which the actual required heat compensation percentage belongs is the fourth target range, the target conduction state is as follows: the first and fourth ends of the first four-way valve 4WV1 are connected, the first and fourth ends of the second four-way valve 4WV2 are connected, the second and third ends of the first three-way valve 3WV1 are connected, the first and third ends of the second three-way valve 3WV2 are connected, the refrigerant shut-off valve is in the closed state, and the first electronic expansion valve Leva1 and the second electronic expansion valve Leva2 are closed; at this time, the flow path of the medium in the distributed heat exchange three-pipe air conditioning heat exchange pipeline is as follows: Figure 5 As shown, in this mode, the first outdoor unit and the second outdoor unit do not circulate refrigerant and do not participate in the evaporation and condensation process.

[0073] When the target range for the actual required heat compensation percentage is the fifth target range, the target conduction state is as follows: the first and fourth ends of the first four-way valve 4WV1 are connected; the third and fourth ends of the second four-way valve 4WV2 are connected; the second and third ends of the first three-way valve 3WV1 are connected; the first and third ends of the second three-way valve 3WV2 are connected; the refrigerant shut-off valve is in the closed state; the first electronic expansion valve Leva1 is closed; and the second electronic expansion valve Leva2 is open. At this time, the flow path of the medium in the distributed heat exchange three-pipe air conditioning heat exchange pipeline is as follows: Figure 6 As shown, in this mode, the first outdoor unit does not circulate refrigerant and does not participate in the evaporation and condensation process.

[0074] When the target range for the actual required heat compensation percentage is the sixth target range, the target conduction state is as follows: the third and fourth ends of the first four-way valve 4WV1 are connected, the third and fourth ends of the second four-way valve 4WV2 are connected, the second and third ends of the first three-way valve 3WV1 are connected, the first and third ends of the second three-way valve 3WV2 are connected, the refrigerant shut-off valve is in the closed state, the first electronic expansion valve Leva1 is open, and the second electronic expansion valve Leva2 is closed. At this time, the flow path of the medium in the distributed heat exchange three-pipe air conditioning heat exchange pipeline is as follows: Figure 7 As shown. In this mode, the second outdoor unit does not circulate refrigerant and does not participate in the evaporation and condensation process.

[0075] When the target range for the actual required heat compensation percentage is the seventh target range, the target conduction state is as follows: the third and fourth ends of the first four-way valve 4WV1 are connected, the third and fourth ends of the second four-way valve 4WV2 are connected, the first and third ends of the first three-way valve 3WV1 and the second three-way valve 3WV2 are connected, the refrigerant shut-off valve is in the closed state, and the first electronic expansion valve Leva1 and the second electronic expansion valve Leva2 are open. At this time, the flow path of the medium in the distributed heat exchange three-pipe air conditioning heat exchange pipeline is as follows: Figure 8 As shown.

[0076] In addition to controlling the switching of the distributed heat exchange three-pipe air conditioning heat exchange circuit between the various operating modes mentioned above, the controller can also realize cold and hot zone control of the outdoor heat exchanger, allowing it to partially cool and partially heat, with the two outdoor heat exchangers alternately acting as evaporators and condensers, achieving a non-stop defrosting function. Specifically, the controller is also used to acquire defrost commands and, based on these commands, control the conduction state of each component in the distributed heat exchange three-pipe air conditioning heat exchange circuit. The defrost commands include a first defrost command, a second defrost command, and a third defrost command.

[0077] When the controller detects a first defrost command, the controller responds to the first defrost command, see [link to relevant documentation]. Figure 9 The first defrosting command is used to control: the first and fourth ends of the first four-way valve 4WV1 are connected, the second and third ends of the first four-way valve 4WV1 are connected, the third and fourth ends of the second four-way valve 4WV2 are connected, the second and third ends of the first three-way valve 3WV1 are connected, the second and third ends of the second three-way valve 3WV2 are connected, the refrigerant shut-off valve is in the closed state, and the first electronic expansion valve Leva1 and the second electronic expansion valve Leva2 are open; at this time, defrosting operation is performed on the first outdoor unit heat exchanger.

[0078] When the controller detects a second defrost command, the controller responds to the second defrost command, see [link to relevant documentation]. Figure 10 The first defrosting command controls the following: the third and fourth terminals of the first four-way valve 4WV1 are connected; the first and fourth terminals of the second four-way valve 4WV2 are connected; the second and third terminals of the first three-way valve 3WV1 and the second three-way valve 3WV2 are connected; the refrigerant shut-off valve is in the open state; and the first electronic expansion valve Leva1 and the second electronic expansion valve Leva2 are open. At this time, defrosting is performed on the second outdoor unit heat exchanger.

[0079] When the controller detects a third defrost command, the controller responds to the third defrost command, see [link to relevant documentation]. Figure 11 The third defrosting command is used to control: the first and fourth ends of the first four-way valve 4WV1 are connected, the second and third ends of the first four-way valve 4WV1 are connected, the third and fourth ends of the second four-way valve 4WV2 are connected, the second and third ends of the first three-way valve 3WV1 are connected, the first and third ends of the second three-way valve 3WV2 are connected, the refrigerant shut-off valve is in the closed state, and the first electronic expansion valve Leva1 and the second electronic expansion valve Leva2 are opened, so as to realize the first indoor unit defrosting without stopping the machine;

[0080] When the controller detects a fourth defrost command, the controller responds to the fourth defrost command, see [link to relevant documentation]. Figure 12 The fourth defrosting command is used to control: the third and fourth ends of the first four-way valve 4WV1 are connected, the first and fourth ends of the second four-way valve 4WV2 are connected, the second and third ends of the first three-way valve 3WV1 are connected, the first and third ends of the second three-way valve 3WV2 are connected, the refrigerant shut-off valve is in the connected state, and the first electronic expansion valve Leva1 and the second electronic expansion valve Leva2 are opened, so as to realize the second indoor unit defrosting without stopping.

[0081] In the technical solution disclosed in this embodiment, the first three-way valve 3wv1 can be installed in the first indoor unit, and the second three-way valve 3wv2 can be installed in the second indoor unit to reduce the number of pipes in the outdoor unit.

[0082] The technical solution disclosed in this embodiment may include two or more compressors connected in parallel, serving as backups for each other. For example, see [link to relevant documentation]. Figure 13The distributed heat exchange three-pipe air conditioning heat exchange pipeline also includes a second compressor TD2. Each interface of the first compressor TD1 is connected to each corresponding interface of the second compressor TD2. At this time, the second compressor TD2 and the first compressor TD1 are mutually redundant. When the first compressor TD1 fails, the second compressor TD2 can be activated and used to replace the first compressor TD1. Furthermore, the distributed heat exchange three-pipe air conditioning heat exchange pipeline may include two compressor systems (each compressor system consists of a compressor, an oil separator OS, a capillary tube, and a refrigerant shut-off valve). One compressor system is a compressor system consisting of a first compressor TD1, a first oil separator OS1, a first capillary tube M1, and a refrigerant shut-off valve SV7. The other compressor system is a compressor system consisting of a second compressor TD2, a second oil separator OS2, a second capillary tube M2, and a refrigerant shut-off valve SV8. The connection relationship of the second compressor TD2, the second oil separator OS2, the second capillary tube M2, and the refrigerant shut-off valve SV8 is the same as the connection relationship of the first compressor TD1, the first oil separator OS1, the first capillary tube M1, and the refrigerant shut-off valve SV7. That is, the two compressor systems have the same structure and connection relationship, and the two compressor systems are backup systems for each other. If one compressor system fails, the other compressor system can be activated.

[0083] See Figure 14 In addition to the above-mentioned distributed heat exchange three-pipe air conditioning heat exchange pipeline technology, the distributed heat exchange three-pipe air conditioning heat exchange pipeline may also include a third four-way valve 4WV3 and a third outdoor unit heat exchanger OC3.

[0084] The first end of the third four-way valve 4WV3 is connected to the second end of the high-pressure pipe Hp via the fifth one-way valve D5. The second end of the third four-way valve 4WV3 is connected to the second end of the low-pressure pipe Lp. The third end of the third four-way valve 4WV3 is connected to the first end of the third outdoor unit heat exchanger OC3 via the sixth one-way valve D6 and the refrigerant shut-off valve SV22. The fourth end of the third four-way valve 4WV3 is connected to the fourth ends of the first four-way valve 4WV1 and the second four-way valve 4WV2. The input end of the fifth one-way valve D5 is connected to the first end of the third four-way valve 4WV3, and the output end of the fifth one-way valve D5 is connected to the second end of the high-pressure pipe Hp. The output end of the sixth one-way valve D6 is connected to the first end of the third outdoor unit heat exchanger OC3 through the refrigerant shut-off valve SV22, and the input end of the sixth one-way valve D5 is connected to the third end of the third four-way valve 4WV3. The third outdoor unit heat exchanger OC3 is connected to the second end of the subcooling device SC through the third electronic expansion valve Leva3. The on / off states of each port of the third four-way valve OC3, refrigerant shut-off valve SV22, and third electronic expansion valve Leva3 are also controlled by the controller. The control logic for the on / off states of each port of the third four-way valve, refrigerant shut-off valve SV22, and third electronic expansion valve is similar to the control logic of the aforementioned scheme. During the design, the status identifiers of the three-way valve, four-way valve, refrigerant shut-off valve, and electronic expansion valve that match each working mode can be pre-written. Once the working mode is determined, corresponding control commands are generated based on the status identifiers of the three-way valve, four-way valve, refrigerant shut-off valve, and electronic expansion valve, so that the states of the three-way valve, four-way valve, refrigerant shut-off valve, and electronic expansion valve are switched to the corresponding conducting state.

[0085] Corresponding to the aforementioned distributed heat exchange three-pipe air conditioning heat exchange pipeline, this application also discloses an air conditioning system, which may include the distributed heat exchange three-pipe air conditioning heat exchange pipeline described in any one of the above claims. See also Figure 15 The air conditioning system may include one indoor unit and multiple outdoor units. Each outdoor unit and the indoor unit form a refrigeration system including a distributed heat exchange three-pipe air conditioning heat exchange pipeline. When the air conditioning system has N outdoor units, the air conditioning system also has N distributed heat exchange three-pipe air conditioning heat exchange pipelines. The N distributed heat exchange three-pipe air conditioning heat exchange pipelines share the first indoor unit and the second indoor unit, as well as the first three-way valve 3wv1, the second three-way valve 3wv2, the high-pressure pipe Hp, the low-pressure pipe Lp, and the liquid pipe.

[0086] For ease of description, the above system is described by dividing it into various modules based on their functions. Of course, in implementing this invention, the functions of each module can be implemented in one or more software and / or hardware components.

[0087] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. Components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0088] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0089] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0090] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0091] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A distributed heat exchange three-pipe air conditioning heat exchange pipeline, characterized in that, Also includes: The first four-way valve has its first end connected to the second end of the high-pressure pipe via a first one-way valve, its second end connected to the second end of the low-pressure pipe, its input end connected to the first end of the first four-way valve, and its output end connected to the second end of the high-pressure pipe. The second four-way valve has its first end connected to the second end of the high-pressure pipe via a second check valve, its second end connected to the second end of the low-pressure pipe, its input end connected to the first end of the second four-way valve, and its output end connected to the second end of the high-pressure pipe. The first outdoor unit heat exchanger has its first end connected to the second ends of the first four-way valve and the second four-way valve in sequence via a refrigerant shut-off valve and a third one-way valve. The first end of the first outdoor unit heat exchanger is also connected to the third end of the second four-way valve via a fourth one-way valve. The second end of the first outdoor unit heat exchanger is connected to the second end of the second outdoor unit heat exchanger. The input end of the third one-way valve is connected to the second ends of the first four-way valve and the second four-way valve. The input end of the fourth one-way valve is connected to the third end of the second four-way valve. The output end of the third one-way valve is connected to the refrigerant shut-off valve. The output end of the fourth one-way valve is connected to the first end of the first outdoor unit heat exchanger. The second end of the first outdoor unit heat exchanger is connected to the second end of the subcooling device. The second outdoor unit heat exchanger has its first end connected to the third end of the first four-way valve, and its second end connected to the second end of the subcooling device. A first compressor, wherein the first end of the first compressor is connected to the fourth end of the first four-way valve and the second four-way valve; A gas-liquid separator, wherein the first end of the gas-liquid separator is connected to the first end of the first outdoor unit heat exchanger, and the second end of the gas-liquid separator is connected to the second end of the first compressor; A subcooling device, wherein a first end of the subcooling device is connected to a second end of a liquid pipe; A first electronic expansion valve is disposed between the second end of the first outdoor unit heat exchanger and the second end of the subcooling device; The second electronic expansion valve is located between the second end of the second outdoor unit heat exchanger and the second end of the subcooling device.

2. The distributed heat exchange three-pipe air conditioning heat exchange pipeline according to claim 1, characterized in that, Also includes: The first three-way valve has its first end connected to the first end of the low-pressure pipe, its second end connected to the first end of the high-pressure pipe, and its third end connected to the first end of the first indoor unit. A first indoor unit, wherein the second end of the first indoor unit is connected to the first end of the liquid pipe; The second three-way valve has its first end connected to the first end of the low-pressure pipe, its second end connected to the first end of the high-pressure pipe, and its third end connected to the first end of the second indoor unit. The second indoor unit has its second end connected to the first end of the liquid pipe.

3. The distributed heat exchange three-pipe air conditioning heat exchange pipeline according to claim 2, characterized in that, Also includes: The controller is used to obtain the actual demand heat compensation percentage and control the conduction state of the first four-way valve, the second four-way valve, the first three-way valve, the second three-way valve and the refrigerant shut-off valve based on the actual demand heat compensation percentage.

4. The distributed heat exchange three-pipe air conditioning heat exchange pipeline according to claim 3, characterized in that, Based on the stated actual demand for heat compensation percentage, the conduction states of the first four-way valve, the second four-way valve, the first three-way valve, the second three-way valve, the refrigerant shut-off valve, the first electronic expansion valve, and the second electronic expansion valve are controlled, including: Determine the target range to which the actual required heat compensation percentage belongs, obtain the target conduction state corresponding to the target range, and control the conduction state of the first four-way valve, the second four-way valve, the first three-way valve, the second three-way valve, the refrigerant shut-off valve, the first electronic expansion valve, and the second electronic expansion valve based on the target conduction state.

5. The distributed heat exchange three-pipe air conditioning heat exchange pipeline according to claim 4, characterized in that, When the target range to which the actual demand heat compensation percentage belongs is the first target range, the target conduction state is as follows: the first end and the fourth end of the first four-way valve are connected, the second end and the third end of the first four-way valve are connected, the first end and the fourth end of the second four-way valve are connected, the second end and the third end of the first three-way valve are connected, the second end and the third end of the second three-way valve are connected, the refrigerant shut-off valve is in the conduction state, and the first electronic expansion valve and the second electronic expansion valve are open; When the target range to which the actual demand heat compensation percentage belongs is the second target range, the target conduction state is as follows: the first end and the fourth end of the first four-way valve are connected, the second end and the third end of the first four-way valve are connected, the first end and the fourth end of the second four-way valve are connected, the second end and the third end of the first three-way valve are connected, the first end and the third end of the second three-way valve are connected, the refrigerant shut-off valve is in the conduction state, and the first electronic expansion valve and the second electronic expansion valve are open; When the target range to which the actual demand heat compensation percentage belongs is the third target range, the target conduction state is as follows: the first end and the fourth end of the first four-way valve are connected, the first end and the fourth end of the second four-way valve are connected, the second end and the third end of the first three-way valve are connected, the first end and the third end of the second three-way valve are connected, the refrigerant shut-off valve is in the conduction state, and the first electronic expansion valve and the second electronic expansion valve are open; When the target range to which the actual demand heat compensation percentage belongs is the fourth target range, the target conduction state is as follows: the first end and the fourth end of the first four-way valve are connected, the first end and the fourth end of the second four-way valve are connected, the second end and the third end of the first three-way valve are connected, the first end and the third end of the second three-way valve are connected, the refrigerant shut-off valve is in the shut-off state, and the first electronic expansion valve and the second electronic expansion valve are closed. When the target range to which the actual demand heat compensation percentage belongs is the fifth target range, the target conduction state is as follows: the first end and the fourth end of the first four-way valve are connected, the third end and the fourth end of the second four-way valve are connected, the second end and the third end of the first three-way valve are connected, the first end and the third end of the second three-way valve are connected, the refrigerant shut-off valve is in the shut-off state, the first electronic expansion valve is closed, and the second electronic expansion valve is open. When the target range to which the actual demand heat compensation percentage belongs is the sixth target range, the target conduction state is as follows: the third and fourth ends of the first four-way valve are connected, the third and fourth ends of the second four-way valve are connected, the second and third ends of the first three-way valve are connected, the first and third ends of the second three-way valve are connected, the refrigerant shut-off valve is in the shut-off state, the first electronic expansion valve is open, and the second electronic expansion valve is closed. When the target range to which the actual demand heat compensation percentage belongs is the seventh target range, the target conduction state is as follows: the third and fourth ends of the first four-way valve are connected, the third and fourth ends of the second four-way valve are connected, the first and third ends of the first three-way valve are connected, the first and third ends of the second three-way valve are connected, the refrigerant shut-off valve is in the shut-off state, and the first and second electronic expansion valves are open.

6. The distributed heat exchange three-pipe air conditioning heat exchange pipeline according to claim 3, characterized in that, The controller is also used for: When the first defrost command is detected, the system responds to the first defrost command, which controls: the first and fourth ends of the first four-way valve are connected, the second and third ends of the first four-way valve are connected, the third and fourth ends of the second four-way valve are connected, the second and third ends of the first three-way valve are connected, the second and third ends of the second three-way valve are connected, the refrigerant shut-off valve is in the shut-off state, and the first and second electronic expansion valves are open. When a second defrost command is detected, the system responds to the second defrost command, which controls: the third and fourth ends of the first four-way valve are connected; the first and fourth ends of the second four-way valve are connected; the second and third ends of the first three-way valve are connected; the second and third ends of the second three-way valve are connected; the refrigerant shut-off valve is in the on state; and the first and second electronic expansion valves are open.

7. The distributed heat exchange three-pipe air conditioning heat exchange pipeline according to claim 3, characterized in that, The controller is also used for: When a third defrost command is detected, the system responds to the third defrost command, which controls: the first and fourth ends of the first four-way valve are connected, the second and third ends of the first four-way valve are connected, the third and fourth ends of the second four-way valve are connected, the second and third ends of the first three-way valve are connected, the first and third ends of the second three-way valve are connected, the refrigerant shut-off valve is in the shut-off state, and the first and second electronic expansion valves are open. When a fourth defrost command is detected, the system responds to the fourth defrost command, which controls: the third and fourth ends of the first four-way valve to be connected; the first and fourth ends of the second four-way valve to be connected; the second and third ends of the first three-way valve to be connected; the first and third ends of the second three-way valve to be connected; the refrigerant shut-off valve to be in the connected state; and the first and second electronic expansion valves to be opened.

8. The distributed heat exchange three-pipe air conditioning heat exchange pipeline according to claim 1, characterized in that, Also includes: The third four-way valve and the third outdoor unit heat exchanger; The third four-way valve has the following configuration: its first end is connected to the second end of the high-pressure pipe via a fifth one-way valve; its second end is connected to the second end of the low-pressure pipe; its third end is connected to the first end of the third outdoor unit heat exchanger via a sixth one-way valve; its fourth end is connected to the fourth ends of both the first and second four-way valves; its input end is connected to the first end of the third four-way valve; its output end is connected to the second end of the high-pressure pipe; its output end is connected to the first end of the third outdoor unit heat exchanger; and its input end is connected to the third end of the third four-way valve. The third outdoor unit heat exchanger is connected to the second end of the subcooling device via a third electronic expansion valve.

9. The distributed heat exchange three-pipe air conditioning heat exchange pipeline according to claim 1, characterized in that, Also includes: The second compressor serves as a backup for the first compressor.

10. An air conditioning system, characterized in that, Includes the distributed heat exchange three-pipe air conditioning heat exchange pipeline as described in any one of claims 1-8.

11. The air conditioning system according to claim 10, characterized in that, The air conditioning system includes N distributed heat exchange three-pipe air conditioning heat exchange pipelines, and the N distributed heat exchange three-pipe air conditioning heat exchange pipelines share the first indoor unit and the second indoor unit, where N is a positive integer not less than 2.

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