Multi-split heat pump system

Abstract

The embodiment of the utility model provides a multi-split heat pump system which comprises a plurality of indoor units and an outdoor unit, the outdoor unit is provided with a plurality of subsystems, each subsystem comprises a compressor and an outdoor heat exchanger which are communicated with each other, one subsystem is at least communicated with one indoor unit, and different subsystems are communicated with different indoor units. According to the multi-split heat pump system, the outdoor unit is separated into the two or more subsystems, so that the situation that the refrigerant charging amount of a single system of the outdoor unit is too large is avoided, the refrigerant of the whole outdoor unit system is managed in a partitioned mode through the mode that the multiple subsystems are separated, and the refrigerant charging amount of the whole outdoor unit system is reduced. The refrigerant charge of the whole system is allocated to the multiple subsystems, the amount of refrigerant entering a room during leakage is reduced to be within a safe range, and the overall safety of the system is improved; in addition, the risk of failure of parts is avoided, and the cost of the block valve and related pipeline pieces and electric control pieces thereof is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of heat pump systems, and in particular to a multi-split heat pump system. Background Art

[0002] In the related art, the refrigerant charge of a one-to-many air conditioner is designed based on multiple indoor units. However, if a refrigerant leaks in one of the indoor units, all the refrigerant may leak into the room of the indoor unit. If the refrigerant has potentially harmful characteristics such as high toxicity or flammability, leaking more than a certain amount of refrigerant into an indoor unit in a closed room may cause danger.

[0003] In this regard, the existing technology manages refrigerant leakage by adding refrigerant sensors and alarming and cutting off when refrigerant leakage occurs. This solution requires adding multiple sensors and control devices to the original air conditioner, which is prone to the failure of one of the sensors or control devices, causing the entire system to lose its refrigerant leakage protection function. Utility Model Content

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a multi-split heat pump system, which aims to reduce the risk of losing the refrigerant leakage protection function due to failure of sensors or control devices and improve the overall safety of the system.

[0005] In a first aspect, an embodiment of the present application provides a multi-split heat pump system, comprising:

[0006] Multiple indoor units;

[0007] An outdoor unit is provided with a plurality of subsystems, each of the subsystems comprises a compressor and an outdoor heat exchanger which are connected to each other, wherein one of the subsystems is connected to at least one of the indoor units, and different subsystems are connected to different indoor units.

[0008] According to some embodiments of the present application, the outdoor unit is provided with an external air duct, and all the subsystems share the external air duct.

[0009] According to some embodiments of the present application, the outdoor unit is provided with a plurality of groups of valve assemblies arranged in an array, each group of the valve assemblies includes a liquid pipe connecting valve and a gas pipe connecting valve, the liquid pipe connecting valve is arranged between a port of the subsystem and a port of the indoor unit, and the gas pipe connecting valve is arranged between another port of the subsystem and another port of the indoor unit.

[0010] According to some embodiments of the present application, different subsystems are connected to different valve assemblies one by one in sequence, and the subsystems connected to the target number of valve assemblies arranged adjacently are all different.

[0011] According to some embodiments of the present application, each of the subsystems further includes a four-way valve, a first port of the four-way valve being connected to the exhaust port of the compressor, a second port being connected to the outdoor heat exchanger, a third port being connected to the return air port of the compressor, and a fourth port being connected to the indoor unit via the liquid pipe connecting valve or the gas pipe connecting valve.

[0012] According to some embodiments of the present application, in the cooling mode, the refrigerant discharged from the exhaust port of the compressor sequentially passes through the first port and the second port of the four-way valve, the outdoor heat exchanger, the indoor unit, the fourth port and the third port of the four-way valve, and then flows back to the return air port of the compressor.

[0013] According to some embodiments of the present application, in the heating mode, the refrigerant discharged from the exhaust port of the compressor sequentially passes through the first port and the fourth port of the four-way valve, the indoor unit, the outdoor heat exchanger, the second port and the third port of the four-way valve, and then flows back to the return air port of the compressor.

[0014] According to some embodiments of the present application, the outdoor unit is further provided with a plurality of throttling components, the number of the throttling components is consistent with the number of the valve assemblies, and the throttling components are arranged between the outdoor heat exchanger and the valve assembly.

[0015] According to some embodiments of the present application, the number of the subsystems is two or three.

[0016] According to some embodiments of the present application, the number of the indoor units is two.

[0017] According to the technical solution of the embodiment of the present application, at least the following beneficial effects are achieved: the multi-split heat pump system of the embodiment of the present application includes multiple indoor units and one outdoor unit, the outdoor unit is provided with multiple subsystems, each of the subsystems includes a connected compressor and an outdoor heat exchanger, wherein one subsystem is connected to at least one indoor unit, and different subsystems are connected to different indoor units. The multi-split heat pump system of the embodiment of the present application avoids excessive refrigerant charge in a single system of the outdoor unit by separating the outdoor unit into two or more subsystems. The embodiment of the present application manages the refrigerant of the entire outdoor unit system in partitions by separating multiple subsystems, distributes the refrigerant charge of the entire system to multiple subsystems, reduces the amount of refrigerant entering the room to a safe range when a leak occurs, and improves the overall safety of the system; in addition, the embodiment of the present application has no risk of component failure, and reduces the cost of the shut-off valve and its related pipeline components and electrical controls.

[0018] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide further understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0020] Figure 1 It is a structural schematic diagram of a multi-split heat pump system provided in one embodiment of the present application. DETAILED DESCRIPTION

[0021] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0022] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0023] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0024] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0025] In some cases, the refrigerant charge of a one-to-many air conditioner is designed based on multiple indoor units, but if one of the indoor units leaks refrigerant, all the refrigerant may leak into the room of the indoor unit. If the refrigerant has potentially hazardous characteristics such as high toxicity or flammability, leaking more than a certain amount of refrigerant into an indoor unit in a closed room may cause danger.

[0026] In this regard, the existing technology manages refrigerant leakage by adding refrigerant sensors and alarming and cutting off when refrigerant leakage occurs. This solution requires adding multiple sensors and control devices to the original air conditioner, which is prone to the failure of one of the sensors or control devices, causing the entire system to lose its refrigerant leakage protection function.

[0027] Based on the above situation, the present application proposes a multi-split heat pump system, which distributes the refrigerant charge of the entire system to multiple subsystems through refrigerant zoning management, and reduces the risk of losing the refrigerant leakage protection function due to failure of sensors or control devices, thereby improving the overall safety of the system.

[0028] The various embodiments of the multi-split heat pump system of the present application are further described below in conjunction with the accompanying drawings.

[0029] like Figure 1 As shown, Figure 1 It is a structural schematic diagram of a multi-split heat pump system provided in one embodiment of the present application.

[0030] In one embodiment, the multi-split heat pump system includes but is not limited to multiple indoor units 200 and one outdoor unit 100. Specifically, the outdoor unit 100 is provided with multiple subsystems, each of which includes but is not limited to a compressor 110 and an outdoor heat exchanger 120, wherein the compressor 110 and the outdoor heat exchanger 120 are connected via a refrigerant pipeline. In addition, one of the subsystems is connected to at least one of the indoor units 200, and different subsystems are connected to different indoor units 200.

[0031] Among them, the number of the above-mentioned subsystems can be two subsystems, three subsystems, or more subsystems, and the embodiments of the present application do not specifically limit this.

[0032] For example, for the currently existing one-to-four air conditioner with an R290 refrigerant filling amount of 900g, if the solution of the embodiment of the present application is adopted, the outdoor unit 100 can be separated into two one-to-two subsystems, and each one-to-two subsystem can be filled with 450g of R290 refrigerant. In this regard, if a one-to-two subsystem leaks, the maximum leakage amount can be controlled to within 450g.

[0033] For another example, for the currently existing one-to-six air conditioner with an R290 refrigerant filling amount of 900g, if the solution of the embodiment of the present application is adopted, the outdoor unit 100 can be separated into three one-to-two subsystems, and each one-to-two subsystem can be filled with 300g of R290 refrigerant. In this regard, if a one-to-two subsystem leaks, the maximum leakage amount can be controlled to within 300g.

[0034] It should be noted that, when the number of subsystems is greater, the amount of refrigerant charged in each subsystem will be lower, so if a refrigerant leak occurs, the refrigerant leakage amount will also be lower.

[0035] In addition, it should be noted that different subsystems are connected to different indoor units 200. In other words, one indoor unit 200 will not be repeatedly connected to multiple different subsystems. On the contrary, if one indoor unit 200 is connected to multiple different subsystems at the same time, the refrigerants of the multiple subsystems will be mixed, that is, if one indoor unit 200 has a refrigerant leak, the refrigerants of the multiple subsystems will also leak.

[0036] It is worth noting that the multi-split heat pump system of the embodiment of the present application avoids excessive refrigerant charge in a single system of the outdoor unit 100 by separating the outdoor unit 100 into two or more subsystems. The embodiment of the present application manages the refrigerant of the entire outdoor unit system by separating multiple subsystems, and distributes the refrigerant charge of the entire system to multiple subsystems, thereby reducing the amount of refrigerant entering the room to a safe range when a leak occurs, thereby improving the overall safety of the system. In addition, the embodiment of the present application has no risk of component failure and eliminates the cost of the shut-off valve and its related piping and electrical components.

[0037] In one embodiment, the number of the indoor units 200 is two, or three, or more, which is not specifically limited in the embodiment of the present application.

[0038] In one embodiment, the outdoor unit 100 is provided with an external air duct, and the external air duct is correspondingly provided with at least one outdoor fan. In addition, all the subsystems can be installed in the external air duct at the same time and share the external air duct, thereby making the structure more compact.

[0039] It should be noted that the embodiment of the present application can appropriately adjust the outdoor fan according to the usage of the subsystem. For example, if the number of subsystems in working state is small, the wind speed of the outdoor fan can be appropriately reduced; if the number of subsystems in working state is large, the wind speed of the outdoor fan can be appropriately reduced.

[0040] Alternatively, the outdoor unit 100 may be provided with a plurality of external air ducts, and one external air duct corresponds to one subsystem, which is not specifically limited in the embodiment of the present application.

[0041] In one embodiment, the outdoor unit 100 is provided with a plurality of groups of valve assemblies arranged in an array, each group of the valve assemblies includes a liquid pipe connecting valve 141 and a gas pipe connecting valve 142, the liquid pipe connecting valve 141 is arranged between a port of the subsystem and a port of the indoor unit 200, and the gas pipe connecting valve 142 is arranged between another port of the subsystem and another port of the indoor unit 200.

[0042] In one embodiment, different subsystems are connected to different valve assemblies one by one in sequence, and the subsystems connected to the target number of adjacently arranged valve assemblies are all different.

[0043] For example, Figure 1 As shown, the multi-split heat pump system is provided with three one-to-two air conditioners, that is, three subsystems and six indoor units 200 ( Figure 1 Five indoor units 200 are omitted in the figure, which are subsystem 1, subsystem 2 and subsystem 3 arranged in sequence; in addition, six liquid pipe connecting valves 141 and gas pipe connecting valves 142 are provided, which are liquid pipe connecting valve A, liquid pipe connecting valve B, liquid pipe connecting valve C, liquid pipe connecting valve D, liquid pipe connecting valve E and liquid pipe connecting valve F, and gas pipe connecting valve A, gas pipe connecting valve B, gas pipe connecting valve C, gas pipe connecting valve D, gas pipe connecting valve E and gas pipe connecting valve F arranged in sequence.

[0044] For the three subsystems, they can be connected to different valve components one by one in the order of subsystem 1, subsystem 2 and subsystem 3. For example, the first valve component such as the liquid pipe connecting valve A and the air pipe connecting valve A are both connected to subsystem 1, the second valve component such as the liquid pipe connecting valve B and the air pipe connecting valve B are both connected to subsystem 2, and the third valve component such as the liquid pipe connecting valve C and the air pipe connecting valve C are both connected to subsystem 3, that is, the first three valve components have been connected to different subsystems one by one, and the connection order of the last three valve components is similar, that is, the fourth valve component such as the liquid pipe connecting valve D and the air pipe connecting valve D are both connected to subsystem 1, the fifth valve component such as the liquid pipe connecting valve E and the air pipe connecting valve E are both connected to subsystem 2, and the sixth valve component such as the liquid pipe connecting valve F and the air pipe connecting valve F are both connected to subsystem 3.

[0045] It should be noted that, for the three subsystems, in addition to being connected to different valve components one by one in the order of subsystem 1, subsystem 2 and subsystem 3, they can also be connected in other orders. For example, they can be connected to different valve components one by one in the order of subsystem 1, subsystem 3 and subsystem 2, that is, the first valve component such as liquid pipe connecting valve A and gas pipe connecting valve A are connected to subsystem 1, and the second valve component such as liquid pipe connecting valve B and gas pipe connecting valve B are connected to In subsystem 3, the third valve component, such as the liquid pipe connecting valve C and the gas pipe connecting valve C, are connected to subsystem 2, that is, the first three valve components have been connected to different subsystems one by one, and the connection sequence of the last three valve components is similar, that is, the fourth valve component, such as the liquid pipe connecting valve D and the gas pipe connecting valve D, are connected to subsystem 1, the fifth valve component, such as the liquid pipe connecting valve E and the gas pipe connecting valve E, are connected to subsystem 3, and the sixth valve component, such as the liquid pipe connecting valve F and the gas pipe connecting valve F, are connected to subsystem 2.

[0046] It is worth noting that before leaving the factory, the subsystems and valve components of the outdoor unit have been connected and installed, and multiple valve components are usually arranged in sequence. Moreover, when the installers connect and install the indoor unit with the outdoor unit, they usually install them according to the arrangement order of the valve components, that is, the indoor unit 1 is installed to the liquid pipe connection valve A and the gas pipe connection valve A, the indoor unit 2 is installed to the liquid pipe connection valve B and the gas pipe connection valve B, and the indoor unit 3 is installed to the liquid pipe connection valve C and the gas pipe connection valve C. Moreover, since the different subsystems are connected to the different valve components one by one in sequence, the indoor unit 1, the indoor unit 2 and the indoor unit 3 each correspond to three different subsystems, thereby better sharing the refrigerant charge.

[0047] On the contrary, if the different subsystems are not connected to the different valve components one by one in sequence. For example, the first and second valve components such as liquid pipe connection valve A, gas pipe connection valve A, liquid pipe connection valve B and gas pipe connection valve B are all connected to subsystem 1, the third and fourth valve components such as liquid pipe connection valve C, gas pipe connection valve C, liquid pipe connection valve D and gas pipe connection valve D are all connected to subsystem 2, and the fifth and sixth valve components such as liquid pipe connection valve E, gas pipe connection valve E, liquid pipe connection valve F and gas pipe connection valve F are all connected to subsystem 3. For the above connection method, when the installer connects and installs the indoor unit with the outdoor unit, he usually installs the indoor unit 1 to the liquid pipe connection valve A and the gas pipe connection valve A, installs the indoor unit 2 to the liquid pipe connection valve B and the gas pipe connection valve B, and installs the indoor unit 3 to the liquid pipe connection valve C and the gas pipe connection valve C, that is, the indoor unit 1 and the indoor unit 2 are both connected to the same subsystem 1, so the refrigerant charge cannot be better shared.

[0048] In one embodiment, each of the subsystems further includes a four-way valve 130, a first port of the four-way valve 130 being connected to the exhaust port of the compressor 110, a second port being connected to the outdoor heat exchanger 120, a third port being connected to the return air port of the compressor 110, and a fourth port being connected to the indoor unit 200 via the liquid pipe connecting valve 141 or the gas pipe connecting valve 142.

[0049] It is understood that the four-way valve 130 is a valve used to control the flow direction of the refrigerant in an air conditioning or refrigeration system. It switches the functions of the air conditioner such as cooling, heating or defrosting by changing the flow direction of the refrigerant. The four-way valve 130 is usually composed of two parts: an electromagnetic pilot valve and a four-way reversing valve. The action of the four-way reversing valve is controlled by the electromagnetic pilot valve. In the cooling mode, the four-way valve 130 will guide the high-pressure refrigerant gas to the outdoor heat exchanger 120 for heat dissipation, and in the heating mode, it will guide the high-pressure refrigerant gas to the indoor heat exchanger for heat dissipation. The working principle of the four-way valve 130 is to control the movement of the slider in the valve by energizing and de-energizing the electromagnetic coil, thereby changing the flow direction of the refrigerant. When cooling, the coil is not energized and the slider moves to the left, while when heating, the coil is energized and the slider moves to the right.

[0050] In one embodiment, the outdoor unit 100 is further provided with a plurality of throttling components 150 , the number of the throttling components 150 is consistent with the number of the valve assemblies, and the throttling components 150 are provided between the outdoor heat exchanger 120 and the valve assembly.

[0051] In one embodiment, in the cooling mode, the refrigerant discharged from the exhaust port of the compressor 110 sequentially passes through the first port and the second port of the four-way valve 130, the outdoor heat exchanger 120, the indoor unit 200, the fourth port and the third port of the four-way valve 130, and then flows back to the return air port of the compressor 110.

[0052] Specifically, for each subsystem, when the air conditioner operates in the cooling mode, the four-way valve 130 will switch to the cooling flow direction, that is, the first port and the second port of the four-way valve 130 are connected, and the fourth port and the third port are connected. In this regard, the refrigerant discharged from the exhaust port of the compressor 110 flows into the outdoor heat exchanger 120 through the first port and the second port of the four-way valve 130 in sequence for condensation and heat release. The condensed refrigerant will flow into the indoor unit 200 through the throttling component 150 for evaporation and heat absorption, thereby cooling the indoor ambient air. Finally, the evaporated refrigerant will flow back to the return air port of the compressor 110 through the fourth port and the third port of the four-way valve 130.

[0053] In one embodiment, in the heating mode, the refrigerant discharged from the exhaust port of the compressor 110 sequentially passes through the first port and the fourth port of the four-way valve 130, the indoor unit 200, the outdoor heat exchanger 120, the second port and the third port of the four-way valve 130, and then flows back to the return air port of the compressor 110.

[0054] Specifically, for each subsystem, when the air conditioner operates in the heating mode, the four-way valve 130 will switch to the heating flow direction, that is, the first port and the fourth port of the four-way valve 130 are connected, and the second port and the third port are connected. In this regard, the refrigerant discharged from the exhaust port of the compressor 110 flows into the indoor unit 200 through the first port and the fourth port of the four-way valve 130 in turn for condensation and heat release, thereby heating the indoor ambient air. The condensed refrigerant will flow into the outdoor heat exchanger 120 through the throttling component 150 for evaporation. Finally, the evaporated refrigerant will flow back to the return air port of the compressor 110 through the second port and the third port of the four-way valve 130.

[0055] In addition, based on the structure of the multi-split heat pump system described above, a verification method for the connection between the internal and external units is proposed below.

[0056] After the equipment is installed, a connection check is performed between the indoor and outdoor units to determine whether the indoor unit is connected to the corresponding subsystem. When the system detects manual settings, it enters the trial operation check.

[0057] First, check that subsystem 1 is connected to the indoor unit:

[0058] The four-way valve of subsystem 1 switches to the cooling flow direction, the compressor runs at the preset frequency Fr, and the throttling component A is opened to the preset opening PlsA. At this time, the evaporator tube temperatures of the six connected indoor units are detected. If the temperature of one evaporator tube drops by more than the preset value X, it is defined as the A indoor unit. The throttling component A is closed, and the throttling component D is opened to the preset opening PlsD. At this time, the evaporator tube temperatures of the six connected indoor units are detected. If the temperature of one evaporator tube drops by more than the preset value X, it is defined as the D indoor unit. After all the indoor units corresponding to the throttling components of subsystem 1 are detected, the compressor stops running.

[0059] The next step is to verify that subsystem 2 is connected to the indoor unit:

[0060] The four-way valve of subsystem 2 switches to the cooling flow direction, the compressor runs at the preset frequency Fr, and the throttling component B is opened to the preset opening PlsB. At this time, the evaporator tube temperatures of the six connected indoor units are detected. If the temperature of one evaporator tube drops by more than the preset value X, it is defined as the B indoor unit. The throttling component B is closed, and the throttling component E is opened to the preset opening PlsE. At this time, the evaporator tube temperatures of the six connected indoor units are detected. If the temperature of one evaporator tube drops by more than the preset value X, it is defined as the E indoor unit. After all the indoor units corresponding to the throttling components of subsystem 2 are detected, the compressor stops running.

[0061] Finally, check that subsystem 3 is connected to the indoor unit:

[0062] The four-way valve of subsystem 3 switches to the cooling flow direction, the compressor runs at the preset frequency Fr, and the throttling component C is opened to the preset opening PlsC. At this time, the evaporator tube temperatures of the six connected indoor units are detected. If the temperature of one evaporator tube drops by more than the preset value X, it is defined as the C indoor unit. The throttling component C is closed, and the throttling component F is opened to the preset opening PlsF. At this time, the evaporator tube temperatures of the six connected indoor units are detected. If the temperature of one evaporator tube drops by more than the preset value X, it is defined as the F indoor unit. After all the indoor units corresponding to the throttling components of subsystem 3 are detected, the compressor stops running.

[0063] At this time, the connection relationship between all indoor units and outdoor units is verified. Among them, the preset frequency Fr range is 10 to 90 Hz, the preset opening Pls range is 50 to 400 pls, and the X range is 1 to 20°C.

[0064] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the above implementation mode. Technical personnel familiar with the field can also make various equivalent modifications or substitutions under the shared conditions without violating the spirit of the present application. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A multi-split heat pump system, characterized in that: include: Multiple indoor units; An outdoor unit is provided with a plurality of subsystems, each of the subsystems comprises a compressor and an outdoor heat exchanger which are connected to each other, wherein one of the subsystems is connected to at least one of the indoor units, and different subsystems are connected to different indoor units.

2. The multi-split heat pump system according to claim 1, characterized in that: The outdoor unit is provided with an outdoor air duct, and all the subsystems share the outdoor air duct.

3. The multi-split heat pump system according to claim 1, characterized in that: The outdoor unit is provided with a plurality of groups of valve components arranged in an array, each group of the valve components includes a liquid pipe connecting valve and a gas pipe connecting valve, the liquid pipe connecting valve is arranged between a port of the subsystem and a port of the indoor unit, and the gas pipe connecting valve is arranged between another port of the subsystem and another port of the indoor unit.

4. The multi-split heat pump system according to claim 3, characterized in that: The different subsystems are connected to the different valve components one by one in sequence, and the subsystems connected to the target number of valve components arranged adjacently are all different.

5. The multi-split heat pump system according to claim 3, characterized in that: Each of the subsystems also includes a four-way valve, a first port of the four-way valve is connected to the exhaust port of the compressor, a second port is connected to the outdoor heat exchanger, a third port is connected to the return air port of the compressor, and a fourth port is connected to the indoor unit through the liquid pipe connecting valve or the gas pipe connecting valve.

6. The multi-split heat pump system according to claim 5, characterized in that: In the cooling mode, the refrigerant discharged from the exhaust port of the compressor sequentially passes through the first port and the second port of the four-way valve, the outdoor heat exchanger, the indoor unit, the fourth port and the third port of the four-way valve, and then flows back to the return air port of the compressor.

7. The multi-split heat pump system according to claim 5, characterized in that: In the heating mode, the refrigerant discharged from the exhaust port of the compressor passes through the first port and the fourth port of the four-way valve, the indoor unit, the outdoor heat exchanger, the second port and the third port of the four-way valve in sequence and then flows back to the return air port of the compressor.

8. The multi-split heat pump system according to claim 3, characterized in that: The outdoor unit is further provided with a plurality of throttling components, the number of which is consistent with the number of the valve assemblies, and the throttling components are arranged between the outdoor heat exchanger and the valve assembly.

9. The multi-split heat pump system according to any one of claims 1 to 8, characterized in that: The number of the subsystems is two or three.

10. The multi-split heat pump system according to any one of claims 1 to 8, characterized in that: The number of the indoor units is two.

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