Heat pump system

Abstract

The embodiment of the utility model provides a heat pump system which comprises an economizer, a first compressor, a first heat exchanger and a second heat exchanger, the first compressor is connected with the first heat exchanger, the second heat exchanger and the economizer, and the heat pump system is further provided with a first one-way valve and a first throttling valve which are arranged between the first heat exchanger and the economizer and connected in parallel. The first one-way valve allows a refrigerant to flow from the first heat exchanger to the economizer; the second one-way valve and the second throttling valve are arranged between the economizer and the second heat exchanger and connected in parallel, and the second one-way valve allows the refrigerant to flow to the economizer from the second heat exchanger. According to the embodiment, the first one-way valve and the first throttling valve which are connected in parallel are arranged between the first heat exchanger and the economizer, the second one-way valve and the second throttling valve which are connected in parallel are arranged between the second heat exchanger and the economizer, an existing one-way bridge structure composed of four one-way valves is replaced, and therefore cost can be reduced.

Description

Technical Field

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

[0002] Currently, the commonly used solutions to increase the load of air-conditioning units include jet enthalpy increase and parallel connection of compressors. Figure 1 FIG. 2 shows a prior art jet enthalpy increase system. Figure 1 As shown, the current jet enthalpy increase mainly adopts economizer 201. When the needs of cooling and heating need to be met at the same time, the running direction of the refrigerant needs to be switched. In order to ensure that the main circuit is throttled after the economizer is overcooled, and to obtain a stable liquid refrigerant at the inlet of the auxiliary circuit (i.e., a stable superheat of the auxiliary circuit), the usual practice is to control the refrigerant direction by using 4 one-way valves to form a one-way bridge 202.

[0003] like Figure 1 As shown, the current parallel compressor solution refers to a solution of connecting more than two compressors 203-1 and 203-2 in parallel. In the prior art, a single larger four-way valve 204 and a three-way structure 205 on the suction side are usually used to control the flow direction and distribution of the refrigerant.

[0004] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present application and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because they are described in the background technology section of the present application. Utility Model Content

[0005] The inventors of the present application have discovered that both the above-mentioned jet reheat increase scheme and the compressor parallel scheme have certain disadvantages. For example, in the existing jet reheat increase scheme, the main line pipe diameter is large, and the one-way valve used in the one-way bridge has a large diameter, so there is a disadvantage of high cost. For another example, in the existing parallel compressor scheme, the distribution effect of the refrigerant is poor when the suction air carries liquid, and the phenomenon of bias flow will occur, that is, one of the compressors has serious liquid return. Distribution bias flow mainly has the following three effects: a. Liquid impact damage to the compressor compression chamber; b. Liquid return dilutes the compressor oil, affecting lubrication, sealing and oil discharge rate, which may cause wear of the compressor air oil; c. Liquid return causes drastic changes in the compressor operating state parameters, such as exhaust temperature, etc., which in turn causes other components of the unit to lose control.

[0006] In order to solve at least one of the above problems, the present application provides a heat pump system, which replaces the existing one-way bridge structure composed of four one-way valves by arranging a first one-way valve and a first throttle valve connected in parallel between the first heat exchanger and the economizer, and arranging a second one-way valve and a second throttle valve connected in parallel between the second heat exchanger and the economizer, thereby reducing costs.

[0007] According to a first aspect of an embodiment of the present application, a heat pump system is provided, comprising an economizer, a first compressor, a first heat exchanger, and a second heat exchanger, wherein the first compressor is connected to the first heat exchanger, the second heat exchanger, and the economizer, wherein the heat pump system further comprises:

[0008] a first one-way valve and a first throttle valve connected in parallel and disposed between the first heat exchanger and the economizer, the first one-way valve allowing refrigerant to flow from the first heat exchanger to the economizer; and

[0009] A second one-way valve and a second throttle valve connected in parallel are arranged between the economizer and the second heat exchanger, and the second one-way valve allows the refrigerant to flow from the second heat exchanger to the economizer.

[0010] According to a second aspect of the embodiment of the present application, the heat pump system further comprises:

[0011] The third heat exchanger;

[0012] a second compressor connected to the third heat exchanger, the second heat exchanger, and the economizer; and

[0013] A third one-way valve and a third throttle valve connected in parallel are arranged between the third heat exchanger and the economizer, and the third one-way valve allows the refrigerant to flow from the third heat exchanger to the economizer.

[0014] According to a third aspect of the embodiment of the present application, the heat pump system further comprises:

[0015] a first four-way valve connected to the first heat exchanger and the first compressor; and

[0016] A second four-way valve is connected to the third heat exchanger and the second compressor.

[0017] According to a fourth aspect of an embodiment of the present application, the first port of the first four-way valve is connected to the exhaust port of the first compressor, the second port of the first four-way valve is connected to the first heat exchanger, the third port of the first four-way valve is connected to the suction port of the first compressor, and the fourth port of the first four-way valve is connected to the second heat exchanger;

[0018] The first port of the second four-way valve is connected to the exhaust port of the second compressor, the second port of the second four-way valve is connected to the third heat exchanger, the third port of the second four-way valve is connected to the intake port of the second compressor, and the fourth port of the second four-way valve is connected to the second heat exchanger.

[0019] According to a fifth aspect of the embodiment of the present application, the heat pump system further comprises:

[0020] a first connecting member connected between the exhaust pipe of the first compressor and the exhaust pipe of the second compressor; and / or

[0021] The second communication member is connected between the suction pipe of the first compressor and the suction pipe of the second compressor.

[0022] According to a sixth aspect of the embodiment of the present application, the first connecting component is a capillary tube, and / or the second connecting component is a capillary tube.

[0023] According to a seventh aspect of the embodiment of the present application, an end portion of the air outlet pipe of the economizer is connected to the air supply port of the first compressor and the air supply port of the second compressor through a first three-way component.

[0024] According to an eighth aspect of the embodiment of the present application, the refrigerant delivery pipe of the second heat exchanger is connected to the fourth port of the first four-way valve and the fourth port of the second four-way valve through a second three-way component.

[0025] The beneficial effect of the present application is that by arranging a first one-way valve and a first throttle valve connected in parallel between the first heat exchanger and the economizer, and arranging a second one-way valve and a second throttle valve connected in parallel between the second heat exchanger and the economizer, the existing one-way bridge structure consisting of four one-way valves is replaced, thereby reducing costs.

[0026] With reference to the following description and accompanying drawings, the specific embodiments of the present application are disclosed in detail, indicating the way in which the principles of the present application can be adopted. It should be understood that the embodiments of the present application are not limited in scope. Within the scope of the spirit and clauses of the appended claims, the embodiments of the present application include many changes, modifications and equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The included drawings are used to provide a further understanding of the embodiments of the present application, which constitute a part of the specification, are used to illustrate the implementation methods of the present application, and together with the text description, explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0028] Figure 1 It is a schematic diagram of a jet enthalpy increase system in the prior art;

[0029] Figure 2 Schematic diagram of the heat pump system of this embodiment. DETAILED DESCRIPTION

[0030] With reference to the accompanying drawings, the above and other features of the present application will become apparent through the following description. In the description and the accompanying drawings, specific embodiments of the present application are specifically disclosed, which show some embodiments in which the principles of the present application can be adopted. It should be understood that the present application is not limited to the described embodiments. On the contrary, the present application includes all modifications, variations and equivalents falling within the scope of the attached claims.

[0031] In the embodiments of the present application, the terms "first", "second", etc. are used to distinguish different elements from the title, but do not represent the spatial arrangement or time sequence of these elements, etc., and these elements should not be limited by these terms. The term "and / or" includes any one and all combinations of one or more of the terms listed in association. The terms "comprising", "including", "having", etc. refer to the existence of the stated features, elements, components or components, but do not exclude the existence or addition of one or more other features, elements, components or components. In the description of the present application, unless otherwise stated, the meaning of "multiple" is two or more.

[0032] In the embodiments of the present application, the singular forms "a", "the", etc. include plural forms and should be broadly understood as "a kind" or "a type" rather than being limited to the meaning of "one"; in addition, the term "the" should be understood to include both singular and plural forms, unless the context clearly indicates otherwise. In addition, the term "according to" should be understood as "at least in part according to...", and the term "based on" should be understood as "at least in part based on...", unless the context clearly indicates otherwise.

[0033] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0034] The present application embodiment provides a heat pump system, Figure 1 FIG. 1 is a schematic diagram of the heat pump system of this embodiment. Figure 1As shown, the heat pump system 100 includes: an economizer 101 , a first compressor 102 , a first heat exchanger 103 and a second heat exchanger 104 .

[0035] The first compressor 102 is connected to the first heat exchanger 103 , the second heat exchanger 104 , and the economizer 101 .

[0036] The heat pump system 100 further includes a first check valve 105 and a first throttle valve 106 which are connected in parallel and are disposed between the first heat exchanger 103 and the economizer 101 . The first check valve 105 allows the refrigerant to flow from the first heat exchanger 103 to the economizer 101 .

[0037] The heat pump system 100 further includes a second one-way valve 107 and a second throttle valve 108 connected in parallel and disposed between the economizer 101 and the second heat exchanger 104 . The second one-way valve 107 allows the refrigerant to flow from the second heat exchanger 104 to the economizer 101 .

[0038] According to the heat pump system 100 of this embodiment, a first one-way valve 105 and a first throttle valve 106 connected in parallel are provided between the first heat exchanger 103 and the economizer 101, and a second one-way valve 107 and a second throttle valve 108 connected in parallel are provided between the second heat exchanger 104 and the economizer 101, thereby replacing the existing one-way bridge structure consisting of four one-way valves, thereby reducing costs.

[0039] For example, the heat pump system 100 is an injection enthalpy system. The first heat exchanger 103 and the second heat exchanger 104 are located indoors or outdoors, respectively. For example, the first heat exchanger 103 is an outdoor heat exchanger, and the second heat exchanger 104 is an indoor heat exchanger. When the heat pump system 100 is in a heating mode, the second heat exchanger 104 is a condenser and the first heat exchanger 103 is an evaporator. When the heat pump system 100 is in a cooling mode, the second heat exchanger 104 is an evaporator and the first heat exchanger 103 is a condenser.

[0040] For another example, the economizer 101 has four ports, namely, a main road outlet 1011, a main road inlet 1012, an auxiliary road outlet 1013, and an auxiliary road inlet 1014. The auxiliary road inlet 1014 of the economizer 101 is connected to the main road outlet 1011 through the fourth throttle valve 119. The main road inlet 1012 of the economizer 101 is connected to the inlet 1041 of the second heat exchanger 104 through the second one-way valve 107 and the second throttle valve 108 connected in parallel, that is, the second one-way valve 107 and the second throttle valve 108 are arranged between the main road inlet 1012 of the economizer 101 and the inlet 1041 of the second heat exchanger 104, and the second one-way valve 107 and the second throttle valve 108 are connected in parallel. Among them, the second one-way valve 107 allows the refrigerant to flow from the second heat exchanger 104 to the economizer 101.

[0041] For another example, the main outlet 1011 of the economizer 101 is connected to the outlet 1031 of the first heat exchanger 103 through the first one-way valve 105 and the first throttle valve 106 connected in parallel, that is, the first one-way valve 105 and the first throttle valve 106 are arranged between the main outlet 1011 of the economizer 101 and the outlet 1031 of the first heat exchanger 103, and the first one-way valve 105 and the first throttle valve 106 are connected in parallel. The first one-way valve 105 allows the refrigerant to flow from the first heat exchanger 103 to the economizer 101.

[0042] For another example, the air inlet 1021 of the first compressor 102 is connected to the auxiliary outlet 1013 of the economizer 101 , and the air outlet 1022 of the first compressor 102 is connected to the first heat exchanger 103 .

[0043] For another example, a liquid storage tank 120 may be further disposed between the inlet 1041 of the second heat exchanger 104 and the main line inlet 1012 of the economizer 101 .

[0044] In some embodiments, the heat pump system 100 further includes a second compressor 109 and a third heat exchanger 110. The second compressor 109 is connected to the third heat exchanger 110, the second heat exchanger 104 and the economizer 101. A third check valve 111 and a third throttle valve 112 connected in parallel are provided between the third heat exchanger 110 and the economizer 101, and the third check valve 111 allows the refrigerant to flow from the third heat exchanger 110 to the economizer 101.

[0045] For example, the third heat exchanger 110 is connected in parallel with the second heat exchanger 104, and the second compressor 109 is connected in parallel with the first compressor 102. The air inlet 1091 of the second compressor 109 is connected to the auxiliary outlet 1013 of the economizer 101, and the exhaust port 1092 of the second compressor 109 is connected to the third heat exchanger 110.

[0046] Thus, the load of the heat pump system 100 can be increased by the parallel structure in which the second compressor 109 is connected in parallel with the first compressor 102 .

[0047] For another example, the main outlet 1011 of the economizer 101 is connected to the outlet 1101 of the third heat exchanger 110 through the third one-way valve 111 and the third throttle valve 112 connected in parallel, that is, the third one-way valve 111 and the third throttle valve 112 are arranged between the main outlet 1011 of the economizer 101 and the outlet 1101 of the third heat exchanger 110, and the third one-way valve 111 and the third throttle valve 112 are connected in parallel. The third one-way valve 111 allows the refrigerant to flow from the third heat exchanger 110 to the economizer 101.

[0048] As another example, the first throttle valve 106 , the second throttle valve 108 , the third throttle valve 112 , and the fourth throttle valve 119 may be expansion valves (EXVs).

[0049] Therefore, a third check valve 111 and a third throttle valve 112 connected in parallel are provided between the third heat exchanger 110 and the economizer 101 to replace the existing one-way bridge structure composed of four check valves, thereby reducing costs.

[0050] In some embodiments, the heat pump system 100 further includes a first four-way valve 113 and a second four-way valve 114. The first four-way valve 113 is connected to the first heat exchanger 103 and the first compressor 102, and the second four-way valve 114 is connected to the third heat exchanger 110 and the second compressor 109.

[0051] For example, the first compressor 102 is connected to the first heat exchanger 103 through the first four-way valve 113. In addition, the first compressor 102 is connected to the second heat exchanger 104 through the first four-way valve 113.

[0052] For another example, the second compressor 109 is connected to the third heat exchanger 110 through the second four-way valve 114. In addition, the second compressor 109 is connected to the second heat exchanger 104 through the second four-way valve 114.

[0053] Therefore, using two smaller first four-way valves 113 and second four-way valves 114 to replace a single larger four-way valve in the prior art can further reduce costs.

[0054] In some embodiments, a first port of the first four-way valve 113 is connected to the exhaust port of the first compressor 102, a second port of the first four-way valve 113 is connected to the first heat exchanger 103, a third port of the first four-way valve 113 is connected to the suction port of the first compressor 102, and a fourth port of the first four-way valve 113 is connected to the second heat exchanger 104. A first port of the second four-way valve 114 is connected to the exhaust port of the second compressor 109, a second port of the second four-way valve 114 is connected to the third heat exchanger 110, a third port of the second four-way valve 114 is connected to the suction port of the second compressor 109, and a fourth port of the second four-way valve 114 is connected to the second heat exchanger 104.

[0055] For example, the first four-way valve 113 has four ports, namely port C, port D, port E, and port S, wherein the first port is D, the second port is C, the third port is S, and the fourth port is E. Port D of the first four-way valve 113 is connected to the exhaust port of the first compressor 102, port C of the first four-way valve 113 is connected to the first heat exchanger 103, port S of the first four-way valve 113 is connected to the suction port of the first compressor 102, and port E of the first four-way valve 113 is connected to the second heat exchanger 104.

[0056] For another example, the second four-way valve 114 has four ports, namely port C, port D, port E, and port S, wherein the first port is D, the second port is C, the third port is S, and the fourth port is E. Port D of the second four-way valve 114 is connected to the exhaust port of the second compressor 109, port C of the second four-way valve 114 is connected to the third heat exchanger 110, port S of the second four-way valve 114 is connected to the suction port of the second compressor 109, and port E of the second four-way valve 114 is connected to the second heat exchanger 104.

[0057] For another example, in the heating mode, due to the low ambient temperature, the suction superheat is likely to be too low, which in turn causes liquid backflow in the first heat exchanger 103 or the third heat exchanger 110. In the present application, since the first compressor 102 and the second compressor 109 are connected to the first heat exchanger 103 and the third heat exchanger 110 through the first four-way valve 113 and the second four-way valve 114, respectively, the first compressor 102 and the second compressor 109 can calculate the superheat of the first heat exchanger 103 and the third heat exchanger 110 according to the suction temperature and the low pressure value, respectively, and then control the opening of the first throttle valve 106 and the third throttle valve 112, respectively, so that the suction of the first compressor 102 and the second compressor 109 is relatively independent, thereby avoiding suction distribution bias, and then avoiding the problem of oil shortage in the compressor.

[0058] In some embodiments, the heat pump system 100 further includes a first communication component 115. The first communication component 115 is connected between the exhaust pipe of the first compressor 102 and the exhaust pipe of the second compressor 109.

[0059] In some embodiments, the heat pump system 100 further includes a second connecting component 116. The second connecting component 116 is connected between the suction pipe of the first compressor 102 and the suction pipe of the second compressor 109.

[0060] Thus, by providing the first communicating member 115 between the exhaust pipe of the first compressor 102 and the exhaust pipe of the second compressor 109, the pressure between the exhaust pipe of the first compressor 102 and the exhaust pipe of the second compressor 109 can be balanced. By providing the second communicating member 116 between the intake pipe of the first compressor 102 and the intake pipe of the second compressor 109, the pressure between the intake pipe of the first compressor 102 and the intake pipe of the second compressor 109 can be balanced.

[0061] In some embodiments, the first connecting component 115 is a capillary tube or other elements capable of connecting.

[0062] In some embodiments, the second connecting component 116 is a capillary tube or other elements capable of connecting.

[0063] In some embodiments, the end of the air outlet pipe of the economizer 101 is connected to the air supply port of the first compressor 102 and the air supply port of the second compressor 109 through the first three-way component 117 .

[0064] For example, the end of the air outlet pipe of the auxiliary outlet 1013 of the economizer 101 is connected to the air supply port of the first compressor 102 and the air supply port of the second compressor 109 through the first three-way component 117. In this way, the flow rate can be evenly distributed.

[0065] In some embodiments, the refrigerant delivery pipe of the second heat exchanger 104 is connected to the fourth port of the first four-way valve 113 and the fourth port of the second four-way valve 114 through the second three-way component 118 .

[0066] For example, the refrigerant delivery pipe of the second heat exchanger 104 is connected to the E port of the first four-way valve 113 and the E port of the second four-way valve 114 through the second three-way component 118. In this way, the flow rate can be evenly distributed.

[0067] The working mode of the heat pump system 100 is described below.

[0068] For example, when the heat pump system 100 is in the heating mode, after the refrigerant flows out from the exhaust port of the first compressor 102, it enters the D port of the first four-way valve 113, then flows out from the E port of the first four-way valve 113, passes through the second heat exchanger 104, the economizer 101 and the first heat exchanger 103 in sequence, then enters the first four-way valve 113 from the C port, flows out from the D port of the first four-way valve 113 and returns to the first compressor 102, completing one cycle. Similarly, after the refrigerant flows out from the exhaust port of the second compressor 109, it enters the D port of the second four-way valve 114, then flows out from the E port of the second four-way valve 114, passes through the second heat exchanger 104, the economizer 101 and the third heat exchanger 110 in sequence, then enters the second four-way valve 114 from the C port, flows out from the D port of the second four-way valve 114 and returns to the second compressor 109, completing one cycle. In the present application, the first compressor 102 and the second compressor 109 can independently control the refrigerant flowing through the first heat exchanger 103 and the third heat exchanger 110 through the first four-way valve 113 and the second four-way valve 114 respectively, thereby avoiding the problem of uneven air intake distribution between the first compressor 102 and the second compressor 109, thereby ensuring the smooth operation of the heat pump system 100.

[0069] For another example, when the heat pump system 100 is in the heating mode, the heat pump system 100 adjusts the opening of the first throttle valve 106 and the third throttle valve 112 respectively, so as to adjust the suction volume of the first compressor 102 and the second compressor 109. For example, the heat pump system 100 adjusts the opening of the first throttle valve 106 and the third throttle valve 112 according to the superheat of the first heat exchanger 103 and the third heat exchanger 110 respectively. For example, the first superheat threshold of the first heat exchanger 103 and the second superheat threshold of the third heat exchanger 110 can be pre-set. When the superheat of the first heat exchanger 103 is less than the first superheat threshold, the opening of the first throttle valve 106 is reduced. When the superheat of the first heat exchanger 103 is greater than the first superheat threshold, the opening of the first throttle valve 106 is increased. The same applies to the adjustment of the first throttle valve 106. In addition, the second throttle valve 108 is in a fully open state, and the opening degree of the fourth throttle valve 119 is adjusted according to the superheat of the auxiliary line inlet 1014 of the economizer 101.

[0070] For another example, when the heat pump system 100 is in cooling mode, the first throttle valve 106 and the third throttle valve 112 are in full open state, the opening of the second throttle valve 108 is adjusted according to the superheat of the second heat exchanger 104, and the opening of the fourth throttle valve 119 is adjusted according to the superheat of the auxiliary inlet 1014 of the economizer 101. For example, a third superheat threshold value may be pre-set. When the superheat of the second heat exchanger 104 is less than the third superheat threshold value, the opening of the second throttle valve 108 is reduced. When the superheat of the second heat exchanger 104 is greater than the third superheat threshold value, the opening of the second throttle valve 108 is increased.

[0071] In addition, the present application may not be limited to Figure 2 In the embodiment shown, Figure 2 For example, in some embodiments, the heat pump system 100 may not have the second compressor 109, the third heat exchanger 110, the second four-way valve 114 and the corresponding components, that is, the structure of the second compressor 109 and the first compressor 102 being connected in parallel is not adopted; for another example, in some embodiments, the heat pump system 100 has the second compressor 109 and the third heat exchanger 110, but does not have the second four-way valve 114 and other components, that is, in the case of adopting the structure of the second compressor 109 and the first compressor 102 being connected in parallel, the second compressor 109 and the first compressor 102 are both connected to the first four-way valve 113.

[0072] The present application is described above in conjunction with specific implementation methods, but it should be clear to those skilled in the art that these descriptions are exemplary and are not intended to limit the scope of protection of the present application. Those skilled in the art can make various modifications and variations to the present application based on the spirit and principles of the present application, and these modifications and variations are also within the scope of the present application.

Claims

1. A heat pump system, comprising an economizer, a first compressor, a first heat exchanger and a second heat exchanger, wherein the first compressor is connected to the first heat exchanger, the second heat exchanger and the economizer, characterized in that: The heat pump system also has: a first one-way valve and a first throttle valve connected in parallel and disposed between the first heat exchanger and the economizer, the first one-way valve allowing refrigerant to flow from the first heat exchanger to the economizer; and A second one-way valve and a second throttle valve connected in parallel are arranged between the economizer and the second heat exchanger, and the second one-way valve allows the refrigerant to flow from the second heat exchanger to the economizer.

2. The heat pump system according to claim 1, characterized in that: The heat pump system further comprises: The third heat exchanger; a second compressor connected to the third heat exchanger, the second heat exchanger, and the economizer; and A third one-way valve and a third throttle valve connected in parallel are arranged between the third heat exchanger and the economizer, and the third one-way valve allows the refrigerant to flow from the third heat exchanger to the economizer.

3. The heat pump system according to claim 2, characterized in that: The heat pump system further comprises: a first four-way valve connected to the first heat exchanger and the first compressor; and A second four-way valve is connected to the third heat exchanger and the second compressor.

4. The heat pump system according to claim 3, characterized in that: The first port of the first four-way valve is connected to the exhaust port of the first compressor, the second port of the first four-way valve is connected to the first heat exchanger, the third port of the first four-way valve is connected to the suction port of the first compressor, and the fourth port of the first four-way valve is connected to the second heat exchanger; The first port of the second four-way valve is connected to the exhaust port of the second compressor, the second port of the second four-way valve is connected to the third heat exchanger, the third port of the second four-way valve is connected to the intake port of the second compressor, and the fourth port of the second four-way valve is connected to the second heat exchanger.

5. The heat pump system according to claim 3, characterized in that: The heat pump system further comprises: a first connecting member connected between the exhaust pipe of the first compressor and the exhaust pipe of the second compressor; and / or The second communication member is connected between the suction pipe of the first compressor and the suction pipe of the second compressor.

6. The heat pump system according to claim 5, characterized in that: The first communicating component is a capillary tube, and / or the second communicating component is a capillary tube.

7. The heat pump system according to claim 3, characterized in that: The end of the air outlet pipe of the economizer is connected to the air supply port of the first compressor and the air supply port of the second compressor through a first three-way component.

8. The heat pump system according to claim 4, characterized in that: The refrigerant delivery pipe of the second heat exchanger is connected to the fourth port of the first four-way valve and the fourth port of the second four-way valve through a second three-way component.

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