Heat Pump System

Abstract

The present invention relates to a heat pump system, comprising a first compressor (1), a second compressor (2), a first condenser (3), a second condenser (4), a first throttling element (5), a first evaporator (6), an ejector (7), a second evaporator (8) and a first control valve (9), wherein the first condenser (3) is connected to the exhaust port of the first compressor (1), the second condenser (4) is connected to the exhaust port of the second compressor (2), the first throttling element (5) is connected to the outlet of the second condenser (4), the first evaporator (6) is connected to the outlet of the first throttling element (5), the ejector (7) is connected to the outlet of the first condenser (3) and the outlet of the first evaporator (6), the second evaporator (8) is connected between the outlet of the ejector (7) and the air inlet of the second compressor (2), and the first control valve (9) is arranged on the connecting pipeline between the exhaust port and the air inlet of the first compressor (1).

Description

Technical Field

[0001] The present invention relates to the technical field of heating, and in particular to a heat pump system. Background Art

[0002] At present, all walks of life advocate low carbon and low energy consumption, and energy conservation is one of the issues that the world is concerned about today. As an energy-saving device that makes full use of low-grade energy, heat pumps have attracted much attention. In cold areas, there is a great demand for high heating temperatures and heating with a large temperature span, so the development of low-temperature heat pump technology suitable for a large temperature span is one of the main development directions of the heat pump industry.

[0003] However, the current large temperature span low temperature heat pump circulation system usually has dual compressors. When the heating demand is small, the operation of the dual compressors will consume a lot of electricity, which will reduce the energy efficiency of the unit and does not meet the requirements of low energy consumption.

[0004] It should be noted that the information disclosed in the background technology section of the present invention is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes prior art already known to those skilled in the art. Summary of the invention

[0005] An embodiment of the present invention provides a heat pump system, which can realize switching between a dual compressor working mode and a single compressor working mode, thereby effectively controlling energy consumption.

[0006] According to one aspect of the present invention, there is provided a heat pump system, comprising:

[0007] The first compressor;

[0008] Second compressor;

[0009] a first condenser, connected to an exhaust port of the first compressor;

[0010] a second condenser, connected to the exhaust port of the second compressor;

[0011] a first throttling element, connected to an outlet of the second condenser;

[0012] a first evaporator, connected to an outlet of the first throttling element;

[0013] an ejector, connected to an outlet of the first condenser and an outlet of the first evaporator;

[0014] A second evaporator connected between the outlet of the ejector and the air inlet of the second compressor; and

[0015] The first control valve is arranged on the connecting pipeline between the exhaust port and the air inlet of the first compressor.

[0016] In some embodiments, the first control valve is a one-way valve, an inlet of the one-way valve is connected to an air inlet of the first compressor, and an outlet of the one-way valve is connected to an exhaust port of the first compressor.

[0017] In some embodiments, the heat pump system further comprises a first heat exchanger, a first inlet of the first heat exchanger being connected to an outlet of the first condenser, a first outlet of the first heat exchanger being connected to an inlet of the ejector, and a first inlet of the first heat exchanger being connected to a first outlet of the first heat exchanger.

[0018] In some embodiments, the heat pump system also includes a second throttling element, which is arranged between the first outlet of the first heat exchanger and the second inlet of the first heat exchanger, the second outlet of the first heat exchanger is connected to the air supply port of the second compressor, and the second inlet of the first heat exchanger is connected to the second outlet of the first heat exchanger.

[0019] In some embodiments, the first heat exchanger is a plate heat exchanger.

[0020] In some embodiments, the heat pump system further comprises a second heat exchanger, a first inlet of the second heat exchanger being connected to an outlet of the second condenser, a first outlet of the second heat exchanger being connected to an inlet of the first evaporator, and a first inlet of the second heat exchanger being connected to a first outlet of the second heat exchanger.

[0021] In some embodiments, the heat pump system also includes a third throttling element, which is arranged between the first outlet of the second heat exchanger and the second inlet of the second heat exchanger, the second outlet of the second heat exchanger is connected to the air intake of the first compressor, and the second inlet of the second heat exchanger is connected to the second outlet of the second heat exchanger.

[0022] In some embodiments, the second heat exchanger is a plate heat exchanger.

[0023] In some embodiments, the heat pump system further comprises a first oil separator, an inlet of the first oil separator being connected to the exhaust port of the first compressor, a first outlet of the first oil separator being connected to the inlet of the first condenser, and a second outlet of the first oil separator being connected to the first compressor.

[0024] In some embodiments, the heat pump system also includes a first connecting pipe connecting the exhaust port of the first compressor and the outlet of the first condenser, a second control valve is provided on the first connecting pipe, and a third control valve is provided on the second connecting pipe between the exhaust port of the first compressor and the inlet of the first oil separator.

[0025] In some embodiments, the heat pump system further comprises a second oil separator, the inlet of the second oil separator being connected to the exhaust port of the second compressor, the first outlet of the second oil separator being connected to the inlet of the second condenser, and the second outlet of the second oil separator being connected to the second compressor.

[0026] In some embodiments, the heat pump system also includes a controller, which is configured to control the first compressor to turn off when the difference between the ambient temperature and the target temperature is less than T, so that the heat pump system enters a single compressor operating mode; and when the difference between the ambient temperature and the target temperature is greater than or equal to T, control the first compressor to turn on, so that the heat pump system enters a dual compressor operating mode, wherein 20℃≤T≤30℃.

[0027] Based on the above technical solution, in the embodiment of the present invention, a first control valve is provided on the connecting pipeline between the exhaust port and the air inlet of the first compressor. By controlling the opening and closing of the first control valve, the working state of the first compressor can be adjusted, thereby realizing the switching of the entire heat pump system between the dual compressor working mode and the single compressor working mode. Under the working condition that both compressors do not need to work, energy consumption can be saved by shutting down the first compressor to meet the energy saving needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0029] Figure 1 The schematic diagram of an embodiment of the heat pump system of the present invention.

[0030] In the figure:

[0031] 1. The first compressor; 2. The second compressor; 3. The first condenser; 4. The second condenser; 5. The first throttling element; 6. The first evaporator; 7. The ejector; 8. The second evaporator; 9. The first control valve; 10. The first heat exchanger; 11. The second throttling element; 12. The second heat exchanger; 13. The third throttling element; 14. The first oil separator; 15. The second control valve; 16. The third control valve; 17. The second oil separator. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be understood that the terms "center", "lateral", "longitudinal", "front", "back", "left", "right", "up", "down", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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 limiting the scope of protection of the present invention.

[0034] like Figure 1 As shown, in some embodiments of the heat pump system provided by the present invention, the heat pump system includes a first compressor 1, a second compressor 2, a first condenser 3, a second condenser 4, a first throttling element 5, a first evaporator 6, an ejector 7, a second evaporator 8 and a first control valve 9, the first condenser 3 is connected to the exhaust port of the first compressor 1, the second condenser 4 is connected to the exhaust port of the second compressor 2, the first throttling element 5 is connected to the outlet of the second condenser 4, the first evaporator 6 is connected to the outlet of the first throttling element 5, the ejector 7 is connected to the outlet of the first condenser 3 and the outlet of the first evaporator 6, the second evaporator 8 is connected between the outlet of the ejector 7 and the air inlet of the second compressor 2, and the first control valve 9 is arranged on the connecting pipeline between the exhaust port and the air inlet of the first compressor 1.

[0035] In the above embodiment, a first control valve 9 is provided on the connecting pipeline between the exhaust port and the air inlet of the first compressor 1. By controlling the opening and closing of the first control valve 9, the working state of the first compressor 1 can be adjusted, thereby realizing the switching of the entire heat pump system between the dual compressor working mode and the single compressor working mode. Under the working condition that both compressors do not need to work, energy consumption can be saved by shutting down the first compressor to meet the demand of energy saving.

[0036] For example, when the first compressor 1 is turned off, that is, the first compressor 1 is in a non-working state, the first control valve 9 can be opened to ensure the normal circulation of the pipeline where the first compressor 1 is located, thereby avoiding the influence of the operation of the entire heat pump system due to the turning off of the first compressor 1; and when the first compressor 1 is turned on, that is, the first compressor 1 is in a working state, the first control valve 9 can be closed to avoid the influence of the pipeline where the first control valve 9 is located on the operation of the first compressor 1.

[0037] When the first compressor 1 is turned on, the first compressor 1 and the second compressor 2 in the heat pump system are both in working condition, and the heat pump system is in a dual compressor working mode. The gas can be compressed simultaneously by the two compressors, which is beneficial to improving the cooling or heating capacity of the system. At the same time, it can also avoid the problem of large system loss or poor reliability caused by a large compressor pressure ratio when only one compressor is used to achieve the same cooling or heating capacity. The dual compressor working mode is particularly suitable for large temperature span conditions.

[0038] When the first compressor 1 is turned off, the first compressor 1 is in a non-working state, the second compressor 2 is in a working state, and the heat pump system is in a single compressor working mode. This working mode is suitable for working conditions with small cooling or heating capacity requirements. By turning off the first compressor 1, compared with the dual compressor working mode, the system energy consumption can be effectively reduced and energy can be saved.

[0039] In some embodiments, the first control valve 9 may be a passive control valve, and the opening or closing of the first control valve 9 is achieved through manual active operation.

[0040] In other embodiments, the first control valve 9 may be an active control valve, and the first control valve 9 automatically controls its opening and closing to achieve an automatic opening and closing effect.

[0041] For example, in some embodiments, the first control valve 9 is a one-way valve, the inlet of the one-way valve is connected to the air inlet of the first compressor 1, and the outlet of the one-way valve is connected to the exhaust port of the first compressor 1. The one-way valve can be automatically opened under the action of the pressure difference between the front and rear of the pipeline, and at the same time limit the reverse flow of the fluid.

[0042] In some embodiments, the heat pump system also includes a first heat exchanger 10, the first inlet of the first heat exchanger 10 is connected to the outlet of the first condenser 3, the first outlet of the first heat exchanger 10 is connected to the inlet of the ejector 7, and the first inlet of the first heat exchanger 10 is connected to the first outlet of the first heat exchanger 10.

[0043] In some embodiments, the heat pump system also includes a second throttling element 11, which is arranged between the first outlet of the first heat exchanger 10 and the second inlet of the first heat exchanger 10, the second outlet of the first heat exchanger 10 is connected to the air supply port of the second compressor 2, and the second inlet of the first heat exchanger 10 is connected to the second outlet of the first heat exchanger 10.

[0044] The first heat exchanger 10 may serve as a subcooler to further cool the refrigerant from the first condenser 3 .

[0045] By connecting the second outlet of the first heat exchanger 10 with the air supply port of the second compressor 2, the second compressor 2 can be supplied with air, and the refrigerant suction amount of the second compressor 2 can be increased, thereby increasing the low pressure.

[0046] By adjusting the opening size of the second throttling element 11, the amount of air supplied to the second compressor 2 can be controlled.

[0047] In some embodiments, the first heat exchanger 10 is a plate heat exchanger, which has good heat exchange effect and is easy to arrange in the pipeline to achieve a supercooling effect.

[0048] In other embodiments, the first heat exchanger 10 may also be a tubular heat exchanger or other types.

[0049] In some embodiments, the heat pump system also includes a second heat exchanger 12, the first inlet of the second heat exchanger 12 is connected to the outlet of the second condenser 4, the first outlet of the second heat exchanger 12 is connected to the inlet of the first evaporator 6, and the first inlet of the second heat exchanger 12 is connected to the first outlet of the second heat exchanger 12.

[0050] In some embodiments, the heat pump system also includes a third throttling element 13, which is arranged between the first outlet of the second heat exchanger 12 and the second inlet of the second heat exchanger 12, the second outlet of the second heat exchanger 12 is connected to the air intake of the first compressor 1, and the second inlet of the second heat exchanger 12 is connected to the second outlet of the second heat exchanger 12.

[0051] The second heat exchanger 12 can serve as a subcooler to further cool the refrigerant from the second condenser 4 .

[0052] By connecting the second outlet of the second heat exchanger 12 with the air inlet of the first compressor 1, a portion of the refrigerant from the second condenser 4 can be distributed to the first compressor 1 to replenish the first compressor 1, thereby achieving the purpose of compressing the gas using the first compressor 1.

[0053] By adjusting the opening size of the third throttling element 13 , the amount of refrigerant distributed to the first compressor 1 can be controlled.

[0054] In some embodiments, the second heat exchanger 12 is a plate heat exchanger, which has good heat exchange effect and is easy to arrange in the pipeline to achieve a supercooling effect.

[0055] In other embodiments, the second heat exchanger 12 may also be a tubular heat exchanger or other types.

[0056] In some embodiments, the heat pump system also includes a first oil separator 14, the inlet of the first oil separator 14 is connected to the exhaust port of the first compressor 1, the first outlet of the first oil separator 14 is connected to the inlet of the first condenser 3, and the second outlet of the first oil separator 14 is connected to the first compressor 1.

[0057] By providing the first oil separator 14, the oil return efficiency of the first compressor 1 can be improved, thereby ensuring high heat exchange efficiency of the heat exchanger in the system.

[0058] In some embodiments, the heat pump system also includes a first connecting pipe connecting the exhaust port of the first compressor 1 and the outlet of the first condenser 3, a second control valve 15 is provided on the first connecting pipe, and a third control valve 16 is provided on the second connecting pipe between the exhaust port of the first compressor 1 and the inlet of the first oil separator 14.

[0059] By providing the second control valve 15 and the third control valve 16 , the connection state of the corresponding connecting pipeline can be adjusted in coordination with the working state of the first compressor 1 .

[0060] For example, when the first compressor 1 is in operation, the second control valve 15 may be closed and the third control valve 16 may be opened; and when the first compressor 1 is in non-operation, the second control valve 15 may be opened and the third control valve 16 may be closed.

[0061] In some embodiments, the heat pump system also includes a second oil separator 17, the inlet of the second oil separator 17 is connected to the exhaust port of the second compressor 2, the first outlet of the second oil separator 17 is connected to the inlet of the second condenser 4, and the second outlet of the second oil separator 17 is connected to the second compressor 2.

[0062] By providing the second oil separator 17, the oil return efficiency of the second compressor 2 can be improved, thereby ensuring high heat exchange efficiency of the heat exchanger in the system.

[0063] In some embodiments, the heat pump system also includes a controller, which is configured to control the first compressor 1 to turn off when the difference between the ambient temperature and the target temperature is less than T, so that the heat pump system enters a single compressor operating mode; and when the difference between the ambient temperature and the target temperature is greater than or equal to T, control the first compressor 1 to turn on, so that the heat pump system enters a dual compressor operating mode, wherein 20℃≤T≤30℃.

[0064] By setting the controller, the heat pump system can automatically switch between the two working modes.

[0065] The following is combined with Figure 1 The structure and working principle of an embodiment of the heat pump system of the present invention are described as follows:

[0066] like Figure 1As shown, the heat pump system includes a first compressor 1, a second compressor 2, a first condenser 3, a second condenser 4, a first throttling element 5, a first evaporator 6, an ejector 7, a second evaporator 8, a first control valve 9, a first heat exchanger 10, a second throttling element 11, a second heat exchanger 12, a third throttling element 13, a first oil separator 14, a second control valve 15, a third control valve 16 and a second oil separator 17.

[0067] The exhaust port of the first compressor 1 is respectively connected to the outlet of the first control valve 9, the inlet of the first oil separator 14 and the inlet of the first condenser 3. The second control valve 15 is provided on the connecting pipeline between the exhaust port of the first compressor 1 and the inlet of the first condenser 3. The first outlet of the first oil separator 14 is connected to the connecting pipeline between the second control valve 15 and the inlet of the first condenser 3. The second outlet of the first oil separator 14 is connected to the oil inlet of the first compressor 1 to realize the oil return of the first compressor 1. The inlet of the first control valve 9 is connected to the air inlet of the first compressor 1.

[0068] The exhaust port of the second compressor 2 is connected to the inlet of the second oil separator 17, the first outlet of the second oil separator 17 is connected to the inlet of the second condenser 4, and the second outlet of the second oil separator 17 is connected to the oil inlet of the second compressor 2, so as to realize the oil return of the second compressor 2.

[0069] The outlet of the first condenser 3 is connected to the first inlet of the first heat exchanger 10, the first outlet of the first heat exchanger 10 is connected to the inlet of the ejector 7, one end of the second throttling element 11 is connected to the connecting pipeline between the first outlet of the first heat exchanger 10 and the inlet of the ejector 7, the other end of the second throttling element 11 is connected to the second inlet of the first heat exchanger 10, and the second outlet of the first heat exchanger 10 is connected to the air supply port of the second compressor 2.

[0070] The outlet of the second condenser 4 is connected to the first inlet of the second heat exchanger 12, the first outlet of the second heat exchanger 12 is connected to the inlet of the first throttling element 5, one end of the third throttling element 13 is connected to the connecting pipeline between the first outlet of the second heat exchanger 12 and the inlet of the first throttling element 5, the other end of the third throttling element 13 is connected to the second inlet of the second heat exchanger 12, and the second outlet of the second heat exchanger 12 is connected to the air intake of the first compressor 1.

[0071] The outlet of the first throttling element 5 is communicated with the inlet of the first evaporator 6, and the outlet of the first evaporator 6 is communicated with the inlet of the ejector 7. The outlet of the ejector 7 is communicated with the inlet of the second evaporator 8, and the outlet of the second evaporator 8 is communicated with the air inlet of the second compressor 2.

[0072] When there is a large temperature span cooling or heating demand, the heat pump system is in a dual compressor working mode, and the high-temperature and high-pressure refrigerant discharged from the first compressor 1 enters the first oil separator 14 to realize oil return. At this time, the second control valve 15 is closed and the third control valve 16 is opened, and then the refrigerant is condensed in the first condenser 3. At this time, due to the effect of the high-pressure side, the first control valve 9 is in a closed state, so the first control valve 9 does not work; the refrigerant flowing out of the first condenser 3 enters the first inlet of the first heat exchanger 10, and a part of the refrigerant flowing out of the first outlet of the first heat exchanger 10 passes through the second throttling element 11 to replenish the second compressor 2, thereby increasing its pressure and increasing the system stability; it can also increase the supercooling of the main refrigerant and increase the heat exchange; then, another part of the refrigerant flowing out of the first outlet of the first heat exchanger 10 enters the ejector 7 for throttling, and the ejector 7 can also absorb the refrigerant from the first evaporator 6 and recover the expansion work; the refrigerant from the first heat exchanger 10 After being mixed with the refrigerant from the first evaporator 6 in the ejector 7, it enters the second evaporator 8. The evaporation temperatures of the first evaporator 6 and the second evaporator 8 are different, so step heat exchange can be achieved to reduce energy loss. Then, the refrigerant flows out of the second evaporator 8 and is absorbed by the second compressor 2 for compression. The refrigerant flowing out of the second compressor 2 enters the second oil separator 17 for oil return, and then enters the second condenser 4, and then enters the first inlet of the second heat exchanger 12. A part of the refrigerant flowing out through the first outlet of the second heat exchanger 12 is supercooled, and then throttled by the first throttling element 5 to a low-temperature and low-pressure liquid refrigerant, and enters the first evaporator 6. Another part of the refrigerant flowing out of the first outlet of the second heat exchanger 12 is throttled by the third throttling element 13 to a low-temperature and low-pressure refrigerant. After heat exchange in the second heat exchanger 12, this part of the refrigerant enters the first compressor 1 for circulation. The second heat exchanger 12 can increase the supercooling degree of the first evaporator 6, thereby increasing the cooling capacity and heating capacity. The third throttling element 13 can control the flow rate entering the first compressor 1, and the second throttling element 11 controls the amount of air supplied to the second compressor 2. The two are coupled to control the injection amount entering the ejector 7 at the same time, making the pressure of the high-pressure second evaporator 8 more stable, thereby improving the stability and reliability of the heat pump system.

[0073] When there is no demand for large temperature span cooling or heating, if the dual compressor working mode continues to operate, a large amount of electricity will be consumed, which is not conducive to the low-carbon energy saving of the heat pump system. Therefore, the heat pump system can be switched to a single compressor working mode.

[0074] The specific switching method may be: the heat pump system further includes a controller, which controls the first compressor 1 to be turned off when the difference between the ambient temperature and the target temperature for cooling or heating is less than T (20°C≤T≤30°C), so that the heat pump system enters a single compressor working mode; and when the difference between the ambient temperature and the target temperature for cooling or heating is greater than or equal to T, controls the first compressor 1 to be turned on, so that the heat pump system enters a dual compressor working mode.

[0075] In the single compressor working mode, the first compressor 1 is turned off, and the refrigerant can flow through the first control valve 9 and no longer pass through the first compressor 1, thereby reducing the energy consumption of the compressor. At this time, the second control valve 15 is opened, and the third control valve 16 is closed. The refrigerant no longer passes through the first oil separator 14, and the system pressure drop is minimized as much as possible. The flow of the remaining refrigerant is similar to the dual compressor working mode. In the single compressor working mode, the first evaporator 6 and the second evaporator 8 can also achieve step heat exchange; but due to the closure of the first compressor 1, the condensation pressures of the first condenser 3 and the second condenser 4 are relatively close. When the first control valve 9 adopts a one-way valve, the system does not need to power the one-way valve, so the working mode of the system can be switched at any time, and the switching is rapid and safe, which greatly improves the stability of the system.

[0076] The heat pump system embodiment provided by the present invention can cope with large temperature span and non-large temperature span environments. The system working mode can be switched freely, and it is fast, safe and reliable. It can make full use of electric energy and heat efficiently. By adjusting the second throttling element 11 and the third throttling element 13, the refrigerant injection amount of the high-pressure second evaporator 8 can be controlled, and the air supply amount to the second compressor 2 can be controlled to improve the energy efficiency of the system. Through the first oil separator 14 and the second oil separator 17, the oil return of the compressor can be improved to ensure the high heat exchange efficiency of the heat exchanger.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that without departing from the principles of the present invention, the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents, and these modifications and equivalent replacements should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A heat pump system, characterized in that: include: A first compressor (1); A second compressor (2); A first condenser (3) connected to an exhaust port of the first compressor (1); A second condenser (4) is connected to the exhaust port of the second compressor (2), and the outlet of the second condenser (4) is connected to the air inlet of the first compressor (1); a first throttling element (5) connected to an outlet of the second condenser (4); a first evaporator (6) connected to an outlet of the first throttling element (5); an ejector (7) connected to the outlet of the first condenser (3) and the outlet of the first evaporator (6); a second evaporator (8) connected between the outlet of the ejector (7) and the air inlet of the second compressor (2); and A first control valve (9) is arranged on a connecting pipeline between an exhaust port and an air inlet of the first compressor (1).

2. The heat pump system according to claim 1, characterized in that: The first control valve (9) is a one-way valve, the inlet of the one-way valve is connected to the air inlet of the first compressor (1), and the outlet of the one-way valve is connected to the exhaust port of the first compressor (1).

3. The heat pump system according to claim 1, characterized in that: It also includes a first heat exchanger (10), wherein a first inlet of the first heat exchanger (10) is connected to an outlet of the first condenser (3), a first outlet of the first heat exchanger (10) is connected to an inlet of the ejector (7), and a first inlet of the first heat exchanger (10) is connected to a first outlet of the first heat exchanger (10).

4. The heat pump system according to claim 3, characterized in that: The invention also comprises a second throttling element (11), wherein the second throttling element (11) is arranged between the first outlet of the first heat exchanger (10) and the second inlet of the first heat exchanger (10), the second outlet of the first heat exchanger (10) is connected to the air supply port of the second compressor (2), and the second inlet of the first heat exchanger (10) is connected to the second outlet of the first heat exchanger (10).

5. The heat pump system according to claim 3, characterized in that: The first heat exchanger (10) is a plate heat exchanger.

6. The heat pump system according to any one of claims 1 to 5, characterized in that: It also includes a second heat exchanger (12), wherein a first inlet of the second heat exchanger (12) is connected to an outlet of the second condenser (4), a first outlet of the second heat exchanger (12) is connected to an inlet of the first evaporator (6), and a first inlet of the second heat exchanger (12) is connected to a first outlet of the second heat exchanger (12).

7. The heat pump system according to claim 6, characterized in that: The invention also comprises a third throttling element (13), wherein the third throttling element (13) is arranged between the first outlet of the second heat exchanger (12) and the second inlet of the second heat exchanger (12), the second outlet of the second heat exchanger (12) is connected to the air inlet of the first compressor (1), and the second inlet of the second heat exchanger (12) is connected to the second outlet of the second heat exchanger (12).

8. The heat pump system according to claim 6, characterized in that: The second heat exchanger (12) is a plate heat exchanger.

9. The heat pump system according to claim 1, characterized in that: It also includes a first oil separator (14), the inlet of the first oil separator (14) is connected to the exhaust port of the first compressor (1), the first outlet of the first oil separator (14) is connected to the inlet of the first condenser (3), and the second outlet of the first oil separator (14) is connected to the first compressor (1).

10. The heat pump system according to claim 9, characterized in that: It also includes a first connecting pipeline connecting the exhaust port of the first compressor (1) and the inlet of the first condenser (3), a second control valve (15) is provided on the first connecting pipeline, and a third control valve (16) is provided on the second connecting pipeline between the exhaust port of the first compressor (1) and the inlet of the first oil separator (14).

11. The heat pump system according to claim 1, characterized in that: It also includes a second oil separator (17), the inlet of the second oil separator (17) is connected to the exhaust port of the second compressor (2), the first outlet of the second oil separator (17) is connected to the inlet of the second condenser (4), and the second outlet of the second oil separator (17) is connected to the second compressor (2).

12. The heat pump system according to claim 1, characterized in that: The heat pump system further comprises a controller, wherein the controller is configured to control the first compressor (1) to be turned off when the difference between the ambient temperature and the target temperature is less than T, so that the heat pump system enters a single compressor operation mode; and to control the first compressor (1) to be turned on when the difference between the ambient temperature and the target temperature is greater than or equal to T, so that the heat pump system enters a dual compressor operation mode, wherein 20°C ≤ T ≤ 30°C.

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