Heat pump system and control method thereof

Abstract

The invention relates to the technical field of air conditioners, in particular to a heat pump system and a control method thereof. The invention aims to solve the problem that a refrigerant is directly ejected from an ejection port of the ejector during low-temperature or low-frequency operation. In order to achieve the purpose, the heat pump system comprises a compressor, an outdoor heat exchanger, an ejector, a first indoor heat exchanger, a second indoor heat exchanger, a gas-liquid separator, a first throttling element, a third indoor heat exchanger, a first bypass pipeline and a second bypass pipeline, one end of a second bypass pipeline is communicated between the second port of the first indoor heat exchanger and the first port of the second indoor heat exchanger, and the other end of the second bypass pipeline is communicated between the second end of the first bypass pipeline and the inlet of the gas-liquid separator; the first valve body is arranged on the second bypass pipeline. The method can operate normally when the system is abnormal, and the user experience is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and particularly relates to a heat pump system and a control method thereof. Background Art

[0002] As a new type of environmentally friendly refrigerant, CO2 (carbon dioxide) has currently become a research hotspot in the heat pump industry. The advantages and disadvantages of a heat pump system using CO2 as a refrigerant are equally obvious. Its advantage is that the heating performance is generally better than that of traditional heat pumps, and its disadvantage is that the refrigeration efficiency is relatively poor. Therefore, how to improve the refrigeration energy efficiency has always been an important reason hindering the popularization of CO2 heat pump systems.

[0003] In response to this problem, the invention patent with the publication number CN113203136B proposes a solution. This invention patent adopts the ejector to recover expansion work technology, which can greatly improve the energy efficiency of the CO2 heat pump system, and adopts a dual-temperature evaporator to further improve the energy efficiency. However, through the actual verification of the inventor, in actual operation, under conditions such as low-temperature working conditions and low-frequency operation of the compressor, abnormalities such as too low inlet pressure of the ejector or too high back pressure at the outlet of the ejector are likely to occur. As a result, the refrigerant cannot eject the low-pressure side refrigerant after entering the ejector, but instead the refrigerant directly sprays out from the ejector injection port. At this time, it will bring the problem that the system cycle cannot operate normally.

[0004] Correspondingly, a new technical solution is needed in this field to solve the above problems. Summary of the Invention

[0005] In order to solve at least one of the above problems in the prior art, that is, to solve the problem that the refrigerant directly sprays out from the ejector injection port under low-temperature working conditions or low-frequency operation of the compressor, in the first aspect of the present application, a heat pump system is provided. The heat pump system includes a compressor, an outdoor heat exchanger, an ejector, a first indoor heat exchanger, a second indoor heat exchanger, a gas-liquid separator, a first throttling element, and a third indoor heat exchanger.

[0006] The exhaust port of the compressor is communicated with the first port of the outdoor heat exchanger. The second port of the outdoor heat exchanger is communicated with the inlet of the ejector. The outlet of the ejector is communicated with the first port of the first indoor heat exchanger. The second port of the first indoor heat exchanger is communicated with the first port of the second indoor heat exchanger. The second port of the second indoor heat exchanger is communicated with the inlet of the gas-liquid separator. The exhaust port of the gas-liquid separator is communicated with the suction port of the compressor. The liquid discharge port of the gas-liquid separator is communicated with the first port of the first throttling element. The second port of the first throttling element is communicated with the first port of the third indoor heat exchanger. The second port of the third indoor heat exchanger is communicated with the injection port of the ejector.

[0007] The heat pump system further includes a first bypass pipeline, a second bypass pipeline, and a first valve body. The first end of the first bypass pipeline is connected between the second port of the third indoor heat exchanger and the injection port of the ejector, and the second end is connected between the second port of the second indoor heat exchanger and the inlet of the gas-liquid separator. The first end of the second bypass pipeline is connected between the second port of the first indoor heat exchanger and the first port of the second indoor heat exchanger, and the second end is connected between the second end of the first bypass pipeline and the inlet of the gas-liquid separator. The first valve body is disposed on the second bypass pipeline.

[0008] In the above technical solution of the present application, by providing the first bypass pipeline, the second bypass pipeline, and the first valve body, when the system operates abnormally, the refrigerant discharged from the injection port of the ejector can be diverted to the second indoor heat exchanger through the first bypass pipeline and the second bypass pipeline to participate in the cycle, ensuring the normal operation of the system and the user experience.

[0009] In a preferred technical solution of the above heat pump system, the heat pump system further includes a second valve body, and the second valve body is disposed between the second end of the first bypass pipeline and the second end of the second bypass pipeline.

[0010] The above setting method can improve the heat exchange effect and operation stability of the system.

[0011] In a preferred technical solution of the above heat pump system, the first valve body and / or the second valve body is an electromagnetic valve.

[0012] In a preferred technical solution of the above heat pump system, the heat pump system further includes a third valve body, and the third valve body is disposed on the first bypass pipeline.

[0013] In a preferred technical solution of the above heat pump system, the third valve body is a one-way valve, and the one-way valve is configured to be conductive when the refrigerant flows from the first end to the second end of the first bypass pipeline.

[0014] In a preferred technical solution of the above heat pump system, the heat pump system further includes a fourth valve body, and the fourth valve body is disposed between the first end of the first bypass pipeline and the injection port of the ejector.

[0015] In a preferred technical solution of the above heat pump system, the heat pump system further includes a four-way valve. The four-way valve includes a first interface, a second interface, a third interface, and a fourth interface. The first interface is connected to the exhaust port of the compressor, the second interface is connected to the first port of the outdoor heat exchanger, the third interface is connected to the suction port of the compressor, and the fourth interface is connected to the exhaust port of the gas-liquid separator.

[0016] In the preferred technical solution of the above heat pump system, the heat pump system further includes a third bypass pipeline and a second throttling element. The first end of the third bypass pipeline is connected between the outlet of the ejector and the first port of the first indoor heat exchanger, and the second end is connected between the second port of the outdoor heat exchanger and the inlet of the ejector. The second throttling element is arranged on the third bypass pipeline.

[0017] The above setting method enables the system to bypass the ejector during the heating process, ensuring the high-efficiency heating of the system.

[0018] In the preferred technical solution of the above heat pump system, the area ratio of the first indoor heat exchanger to the second indoor heat exchanger is less than or equal to 1:1.

[0019] The above setting method can ensure that the cooling capacity of the refrigerant is utilized to a greater extent under abnormal operating conditions of the system, guaranteeing the heat exchange effect of the system.

[0020] In the second aspect of the present application, there is provided a control method for the heat pump system described in the first aspect above. The control method includes:

[0021] Obtain the temperature at the first end of the first indoor heat exchanger and the temperature at the second end of the third indoor heat exchanger;

[0022] Based on the temperature at the first end and the temperature at the second end, determine whether the heat pump system is abnormal;

[0023] When the heat pump system is abnormal, control the first valve body to open and the first throttling element to close; or

[0024] Obtain the pressure at the second end of the third indoor heat exchanger and the pressure at the first end of the first indoor heat exchanger;

[0025] Based on the pressure at the second end and the pressure at the first end, determine whether the heat pump system is abnormal;

[0026] When the heat pump system is abnormal, control the first valve body to open and the first throttling element to close; or

[0027] Obtain the temperature at the second end of the third indoor heat exchanger;

[0028] Based on the temperature at the second end and a preset temperature threshold, determine whether the heat pump system is abnormal;

[0029] When the heat pump system is abnormal, control the first valve body to open and the first throttling element to close.

[0030] The control method of the present application can determine whether the system is abnormal by comparing the temperature of the first port of the first indoor heat exchanger with the temperature of the second end of the third indoor heat exchanger, or by comparing the temperature of the second end of the third indoor heat exchanger with a preset temperature difference threshold, or by comparing the pressure of the second end of the third indoor heat exchanger with the pressure of the first end of the first indoor heat exchanger. When the system is abnormal, the pipeline can be switched in time to ensure the normal operation of the system and ensure the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present application will be described below with reference to the accompanying drawings. In the drawings:

[0032] Figure 1 is a system diagram of the heat pump system of the present application;

[0033] Figure 2 is a flowchart of the first implementation manner of the control method of the heat pump system of the present application;

[0034] Figure 3 is a flowchart of the second implementation manner of the control method of the heat pump system of the present application.

[0035] List of Reference Numerals

[0036] 1. Compressor; 2. Outdoor heat exchanger; 3. Regenerator; 4. Injector; 5. First indoor heat exchanger; 6. Second indoor heat exchanger; 7. Third indoor heat exchanger; 8. Gas-liquid separator; 9. First throttling element; 10. First bypass pipeline; 11. Second bypass pipeline; 12. First valve body; 13. Second valve body; 14. Third valve body; 15. Fourth valve body; 16. Third bypass pipeline; 17. Second throttling element; 18. Four-way valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present application and are not intended to limit the protection scope of the present application. For example, although the third valve body in the drawings is described in combination with a check valve, the specific structural form of the third valve body is not fixed, and those skilled in the art can adjust it according to needs to adapt to specific application scenarios. For example, the third valve body can also adopt a solenoid valve, an electronic expansion valve, etc.

[0038] It should be noted that in the description of this application, the terms indicating directions or positional relationships such as "upper", "lower", "left", "right", etc. are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or component must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to this application. In addition, the terms "first", "second", "third", "fourth" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0039] In addition, it should be noted that in the description of this application, unless otherwise clearly specified and defined, the terms "connected", "linked", "connected to" 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 directly connected, or indirectly connected through an intermediate medium, and can be the connection inside two components. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] First, refer to Figure 1 , and describe the heat pump system of this application.

[0041] As Figure 1 shown, in order to solve the problem that the refrigerant directly sprays out from the ejector injection port under low-temperature conditions or when the compressor operates at low frequency, the heat pump system of this application includes a compressor 1, an outdoor heat exchanger 2, an ejector 4, a first indoor heat exchanger 5, a second indoor heat exchanger 6, a gas-liquid separator 8, a first throttling element 9, and a third indoor heat exchanger 7. The exhaust port of the compressor 1 is connected to the first port ( Figure 1 right port) of the outdoor heat exchanger 2, the second port ( Figure 1 left port) of the outdoor heat exchanger 2 is connected to the inlet of the ejector 4, the outlet of the ejector 4 is connected to the first port ( Figure 1 left port) of the first indoor heat exchanger 5, the second port ( Figure 1 right port) of the first indoor heat exchanger 5 is connected to the first port ( Figure 1 left port) of the second indoor heat exchanger 6, the second port ( Figure 1 right port) of the second indoor heat exchanger 6 is connected to the inlet of the gas-liquid separator 8, the exhaust port of the gas-liquid separator 8 is connected to the suction port of the compressor 1, the liquid discharge port of the gas-liquid separator 8 is connected to the first port ( Figure 1 right port) of the first throttling element 9, the second port ( Figure 1 left port) of the first throttling element 9 is connected to the first port ( Figure 1 right port) of the third indoor heat exchanger 7, and the second port ( Figure 1 left port) of the third indoor heat exchanger 7 is connected to the injection port of the ejector 4.

[0042] The heat pump system further includes a first bypass pipeline 10, a second bypass pipeline 11 and a first valve body 12. The first end ( Figure 1 left end) of the first bypass pipeline 10 is connected between the second port ( Figure 1 left side port) of the third indoor heat exchanger 7 and the injection port of the ejector 4. The second end ( Figure 1 right end) of the first bypass pipeline 10 is connected between the second port of the second indoor heat exchanger 6 and the inlet of the gas-liquid separator 8. The first end ( Figure 1 left end) of the second bypass pipeline 11 is connected between the second port of the first indoor heat exchanger 5 and the first port of the second indoor heat exchanger 6. The second end ( Figure 1 right end) of the second bypass pipeline 11 is connected between the second end of the first bypass pipeline 10 and the inlet of the gas-liquid separator 8. The first valve body 12 is arranged on the second bypass pipeline 11.

[0043] When the heat pump system is in operation, the refrigerant discharged from the compressor 1 first enters the outdoor heat exchanger 2 to exchange heat with the outdoor air. After the heat exchange is completed, the refrigerant enters the ejector 4 from the inlet of the ejector 4 and is ejected from the outlet of the ejector 4 into the first indoor heat exchanger 5 to exchange heat with the indoor air. The refrigerant discharged from the first indoor heat exchanger 5 then enters the second indoor heat exchanger 6 to exchange heat with the indoor air. The heat-exchanged refrigerant enters the gas-liquid separator 8. The refrigerant entering the gas-liquid separator 8 is divided into two paths. Among them, the gaseous refrigerant is discharged from the exhaust port of the gas-liquid separator 8 and flows back to the compressor 1 from the suction port of the compressor 1. The liquid refrigerant in the gas-liquid separator 8 is discharged from the drain port of the gas-liquid separator 8 and enters the third indoor heat exchanger 7 to exchange heat with the indoor air after passing through the throttling and pressure reduction of the first throttling element 9. The heat-exchanged refrigerant flows back to the ejector 4 through the injection port of the ejector 4 and mixes with the refrigerant in the ejector 4 to continue to participate in the cycle.

[0044] When an abnormality occurs in the heat pump system, the outlet and the injection port of the ejector 4 simultaneously eject the refrigerant outward. The refrigerant discharged from the outlet of the ejector 4 passes through the first indoor heat exchanger 5 and the second indoor heat exchanger 6 and enters the gas-liquid separator 8. The refrigerant discharged from the injection port of the ejector 4 passes through the third indoor heat exchanger 7 and the first throttling element 9 and enters the gas-liquid separator 8, and the system cannot circulate normally. At this time, the first throttling element 9 can be controlled to close. The refrigerant ejected from the outlet of the ejector 4 enters the first indoor heat exchanger 5 to exchange heat with the indoor air. The refrigerant ejected from the injection port of the ejector 4 enters the second indoor heat exchanger 6 through the first bypass pipeline 10 to exchange heat with the indoor air. At least part of the refrigerant discharged from the first indoor heat exchanger 5 and the second indoor heat exchanger 6 is mixed in the second bypass pipeline 11, and then enters the gas-liquid separator 8 through the first valve body 12 to continue to participate in the cycle.

[0045] With the above technical solution of the present application, by providing the first bypass pipeline 10, the second bypass pipeline 11 and the first valve body 12, when the system operates abnormally, the refrigerant discharged from the ejector port of the ejector 4 can be diverted to the second indoor heat exchanger 6 through the first bypass pipeline 10 and the second bypass pipeline 11 to participate in the cycle, ensuring the normal operation of the system and the user experience.

[0046] The following further refers to Figure 1 and introduces a preferred embodiment of the present application.

[0047] As Figure 1 shown, in a preferred embodiment, the heat pump system includes a compressor 1, a four-way valve 18, an outdoor heat exchanger 2, a regenerator 3, an ejector 4, a first indoor heat exchanger 5, a second indoor heat exchanger 6, a third indoor heat exchanger 7, a gas-liquid separator 8, a first throttling element 9, a second throttling element 17, a first bypass pipeline 10, a second bypass pipeline 11 and a third bypass pipeline 16.

[0048] The four-way valve 18 has four interfaces, namely a first interface a, a second interface b, a third interface c and a fourth interface d. The regenerator 3 has a first port ( Figure 1 the upper left port in Figure 1 ), a second port ( Figure 1 the lower left port in Figure 1 ), a third port (

[0049] the lower right port in Figure 1 ), and a fourth port ( Figure 1The lower left port is communicated with the inlet of the ejector 4. The outlet of the ejector 4 is communicated with the first port of the first indoor heat exchanger 5. The second port of the first indoor heat exchanger 5 is communicated with the first port of the second indoor heat exchanger 6. The second port of the second indoor heat exchanger 6 is communicated with the inlet of the gas-liquid separator 8. And a second valve body 13 is arranged between the second port of the second indoor heat exchanger 6 and the inlet of the gas-liquid separator 8. The first end of the second bypass pipeline 11 is communicated with the pipeline between the second port of the first indoor heat exchanger 5 and the first port of the second indoor heat exchanger 6. The second end of the second bypass pipeline 11 is communicated with the pipeline between the second valve body 13 and the inlet of the gas-liquid separator 8. A first valve body 12 is arranged on the second bypass pipeline 11. Preferably, both the first valve body 12 and the second valve body 13 are solenoid valves.

[0050] Continue to refer to Figure 1 The exhaust port of the gas-liquid separator 8 is communicated with the fourth interface d of the four-way valve 18. The third interface c of the four-way valve 18 is communicated with the third port of the regenerator 3. The fourth port of the regenerator 3 is communicated with the suction port of the compressor 1. The liquid discharge port of the gas-liquid separator 8 is communicated with the first port of the first throttling element 9. The first throttling element 9 is preferably an electronic expansion valve. The second port of the first throttling element 9 is communicated with the first port of the third indoor heat exchanger 7. The second port of the third indoor heat exchanger 7 is communicated with the ejecting port of the ejector 4. And a fourth valve body 15 is arranged between the second port of the third indoor heat exchanger 7 and the ejecting port of the ejector 4. The fourth valve body 15 is a solenoid valve. The first end of the first bypass pipeline 10 is communicated with the pipeline between the second port of the third indoor heat exchanger 7 and the fourth valve body 15. The second end of the first bypass pipeline 10 is communicated with the pipeline between the second end of the second indoor heat exchanger 6 and the second valve body 13. A third valve body 14 is arranged on the second bypass pipeline 11. The third valve body 14 is preferably a check valve, and the check valve is opened when the refrigerant flows from the first end to the second end of the first bypass pipeline 10.

[0051] The first end of the third bypass pipeline 16 is communicated with the pipeline between the first port of the first indoor heat exchanger 5 and the outlet of the ejector 4. The second end is communicated with the pipeline between the second port of the regenerator 3 and the inlet of the ejector 4. A second throttling element 17 is arranged on the third bypass pipeline 16. The second throttling element 17 is preferably an electronic expansion valve.

[0052] Furthermore, the area ratio of the first indoor heat exchanger 5 to the second indoor heat exchanger 6 is less than or equal to 1:1. Preferably, the area ratio of the two is 1:1.

[0053] Next, in conjunction with Figure 1 and in combination with the refrigeration operation process, the working principle of the heat pump system of the present application will be introduced.

[0054] During the refrigeration operation, the first valve body 12 and the second throttling element 17 are closed, the first throttling element 9 is opened to a certain opening degree, and the second valve body 13 and the fourth valve body 15 are opened. At this time, the refrigerant discharged from the compressor 1 passes through the first interface a and the second interface b of the four-way valve 18 and then enters the outdoor heat exchanger 2 to exchange heat with the outdoor air. After the heat exchange is completed, the refrigerant enters the first heat exchange flow path of the regenerator 3 to exchange heat with the refrigerant in the second heat exchange flow path. The refrigerant discharged from the regenerator 3 enters the ejector 4 from the inlet of the ejector 4 and is ejected from the outlet of the ejector 4 into the first indoor heat exchanger 5 to exchange heat with the indoor air. The refrigerant after heat exchange enters the second indoor heat exchanger 6 to exchange heat with the indoor air, and then the refrigerant after heat exchange enters the gas-liquid separator 8. The refrigerant entering the gas-liquid separator 8 is divided into two paths. The gaseous refrigerant is discharged from the exhaust port of the gas-liquid separator 8, and after passing through the fourth interface d and the third interface c of the four-way valve 18, it enters the second heat exchange flow path of the regenerator 3 to exchange heat with the first heat exchange flow path, and finally returns to the compressor 1 from the suction port of the compressor 1. The liquid refrigerant in the gas-liquid separator 8 enters the first indoor heat exchanger 5 to exchange heat with the indoor air after throttling and pressure reduction by the first throttling element 9. The refrigerant after heat exchange returns to the ejector 4 through the injection port of the ejector 4, mixes with the refrigerant in the ejector 4, and then continues to participate in the cycle.

[0055] When an abnormality occurs in the heat pump system, the outlet and the injection port of the ejector 4 eject the refrigerant outward at the same time. The refrigerant discharged from the outlet of the ejector 4 passes through the first indoor heat exchanger 5 and the second indoor heat exchanger 6 and enters the gas-liquid separator 8. The refrigerant discharged from the injection port of the ejector 4 passes through the third indoor heat exchanger 7 and the first throttling element 9 and enters the gas-liquid separator 8, and the system cannot circulate normally. At this time, control the first throttling element 9 to close, open the first valve body 12, close the second valve body 13. The refrigerant ejected from the outlet of the ejector 4 enters the first indoor heat exchanger 5 to exchange heat with the indoor air, and the refrigerant ejected from the injection port of the ejector 4 passes through the first bypass pipeline 10 and enters the second indoor heat exchanger 6 to exchange heat with the indoor air. The refrigerant discharged from the first indoor heat exchanger 5 and the second indoor heat exchanger 6 is mixed in the second bypass pipeline 11, then enters the gas-liquid separator 8 through the first valve body 12, and continues to participate in the cycle.

[0056] During the heating operation, the first valve body 12, the second valve body 13, and the fourth valve body 15 are closed, the first throttling element 9 is fully open, and the second throttling element 17 is opened to a certain opening degree. The refrigerant discharged from the compressor 1 enters the gas-liquid separator 8 through the first interface a and the fourth interface d of the four-way valve 18 and then enters the gas-liquid separator 8 through the exhaust port of the gas-liquid separator 8. All the refrigerant entering the gas-liquid separator 8 is discharged through the drain port, and after passing through the first throttling element 9, it enters the third indoor heat exchanger 7 to exchange heat with the indoor air for the first time. The refrigerant after heat exchange enters the second indoor heat exchanger 6 through the first bypass pipeline 10 to exchange heat with the indoor air for the second time. The refrigerant after heat exchange enters the first indoor heat exchanger 5 to exchange heat with the indoor air for the third time. The refrigerant after heat exchange enters the first heat exchange flow path of the regenerator 3 through the third bypass pipeline 16 and exchanges heat with the refrigerant in the second heat exchange flow path. The refrigerant discharged from the first heat exchange flow path of the regenerator 3 exchanges heat with the outdoor air through the outdoor heat exchanger 2, and then enters the second heat exchange flow path of the regenerator 3 through the second interface b and the third interface c of the four-way valve 18 to exchange heat with the first heat exchange flow path, and finally returns to the compressor 1 through the suction port of the compressor 1.

[0057] In the above preferred embodiment, when the ejector 4 is abnormal, the refrigerant discharged from the ejector port can be diverted to the second indoor heat exchanger 6 through the first bypass pipeline 10 and the second bypass pipeline 11 to participate in the cycle, ensuring the normal operation of the system and the user experience. By setting the second valve body 13, the heat exchange effect and operation stability of the system can be improved. By setting the third bypass pipeline 16, the system can bypass the ejector 4 during the heating process, ensuring the high-efficiency heating of the system. The area ratio of the first indoor heat exchanger 5 to the second indoor heat exchanger 6 is preferably 1:1, which can ensure that the cold quantity of the refrigerant is utilized to a greater extent under abnormal operation conditions of the system and ensure the heat exchange effect of the system.

[0058] It should be noted that the above preferred embodiments are only used to illustrate the principle of the present application and are not intended to limit the protection scope of the present application. Without departing from the principle of the present application, those skilled in the art can adjust the above setting methods so that the present application can be applied to more specific application scenarios.

[0059] For example, in an alternative embodiment, the setting of the second valve body 13 is not necessary, and those skilled in the art can choose whether to set the second valve body 13 based on specific requirements.

[0060] For another example, in another alternative embodiment, the setting of the third valve body 14 is not necessary either. Under the condition that the normal operation of the system can be ensured, the third valve body 14 can be omitted.

[0061] For another example, in another alternative embodiment, the setting of the fourth valve body 15 is not necessary, and those skilled in the art can choose whether to set this valve body.

[0062] For another example, in another alternative embodiment, although the above embodiment is introduced by taking the heat regenerator 3 and the four-way valve 18 as an example, the arrangements of the heat regenerator 3 and the four-way valve 18 are only one possible embodiment, and those skilled in the art can choose whether to arrange the two based on the application scenario.

[0063] For another example, in an alternative embodiment, the connection mode of the interfaces of the four-way valve 18 is not unique. For example, although this application is described by combining the connection between the third interface c of the four-way valve 18 and the third port of the heat regenerator 3, and the exhaust port of the gas-liquid separator 8 and the fourth interface d of the four-way valve 18, this is only exemplary. Those skilled in the art can also adjust this connection mode. For example, the exhaust port of the gas-liquid separator 8 is connected to the third port of the heat regenerator 3, the fourth port of the heat regenerator 3 is connected to the fourth interface d of the four-way valve 18, and the third interface c of the four-way valve 18 is connected to the suction port of the compressor 1. In short, as long as the third interface c of the four-way valve 18 can be directly or indirectly connected to the suction port of the compressor 1, and the fourth interface d of the four-way valve 18 can be directly or indirectly connected to the exhaust port of the gas-liquid separator 8.

[0064] For another example, in an alternative embodiment, the arrangements of the third bypass pipeline 16 and the second throttling element 17 are only exemplary and are not intended to limit the protection scope of this application. Those skilled in the art can also not arrange the third bypass pipeline 16 and the second throttling element 17. At this time, the refrigerant will circulate through the ejector 4 during the heating process.

[0065] For another example, in an alternative embodiment, other ratios can also be adopted between the areas of the first indoor heat exchanger 5 and the second indoor heat exchanger 6. Of course, in order to make the best use of the cooling capacity of the refrigerant, setting it to 1:1 is a better way.

[0066] For another example, the specific structural forms of the first valve body 12, the second valve body 13, the third valve body 14 and the fourth valve body in the above embodiment are not unique, and those skilled in the art can replace them as long as the corresponding functions can be achieved. For example, the one-way valve can be replaced by a solenoid valve or other electrically controlled valves, and the solenoid valve can be replaced by an electronic expansion valve or other electrically controlled valves, etc.

[0067] Of course, the above alternative embodiments, as well as between the alternative embodiments and the preferred embodiments, can also be cross-matched and used to combine new embodiments to be applicable to more specific application scenarios.

[0068] Next, with reference to Figure 2 and Figure 3 , the control method of this application will be introduced.

[0069] First, refer to Figure 2 , corresponding to the above heat pump system, the present application also provides a control method for a heat pump system, including:

[0070] S101, obtaining the temperature at the first end of the first indoor heat exchanger and the temperature at the second end of the third indoor heat exchanger; for example, when the system operates in the refrigeration mode or the dehumidification mode, the temperature at the first end of the first indoor heat exchanger and the temperature at the second end of the third indoor heat exchanger are obtained by respectively arranging temperature sensors on the pipeline at the first end of the first indoor heat exchanger and the pipeline at the second end of the third indoor heat exchanger.

[0071] S103, based on the temperature at the first end and the temperature at the second end, determining whether the heat pump system is abnormal; for example, by calculating the difference between the temperature at the first end and the temperature at the second end, and comparing the difference with a preset temperature difference threshold to determine whether the heat pump system is abnormal. For example, when the heat pump system operates normally, the refrigerant flows into the first indoor heat exchanger from the first port (i.e., Figure 1 the left port) and exchanges heat with the indoor air, and then after heat exchange in the second indoor heat exchanger, flow splitting in the gas-liquid separator, and throttling by the first throttling element, it flows into the first port of the third indoor heat exchanger (i.e., Figure 1 the right port) to exchange heat with the indoor air, and finally flows out from the second port of the third indoor heat exchanger (i.e., Figure 1 the left port). Therefore, the temperature at the first end of the first indoor heat exchanger is theoretically higher than the temperature at the second end of the third indoor heat exchanger. Through actual tests by the inventor, the difference between the two is usually between 2 - 10°C. When an abnormality occurs, part of the refrigerant enters the first indoor heat exchanger from the first port of the first indoor heat exchanger, and another part of the refrigerant enters the third indoor heat exchanger from the second port of the third indoor heat exchanger. At this time, the temperature at the first end of the first indoor heat exchanger is basically equal to the temperature at the second end of the third indoor heat exchanger, or the temperature difference is very small. Thus, after obtaining the temperature at the first end of the first indoor heat exchanger and the temperature at the second end of the third indoor heat exchanger, calculate the difference between the two, and based on whether the difference is greater than the temperature difference threshold, it can be determined whether the heat pump system is abnormal. Among them, the temperature difference threshold can be determined within the range of 2 - 10°C.

[0072] S105, when the heat pump system is abnormal, controlling the first valve body to open and the first throttling element to close. For example, when it is determined that the heat pump system is abnormal, control the first valve body to open and the first throttling element to close, and realize the circulation of the refrigerant through the parallel connection of the first indoor heat exchanger and the second indoor heat exchanger.

[0073] Of course, the method of determining whether the heat pump system is abnormal by calculating the difference between the temperature at the first end and the temperature at the second end is only an example. Those skilled in the art can adjust it. For example, it can also be determined whether the heat pump system is abnormal by calculating the ratio of the two and comparing it with a preset ratio threshold, etc.

[0074] For another example, in an alternative implementation, the system abnormality can also be determined based on the temperature at the second end of the third indoor heat exchanger. For example, when the system is operating normally, the refrigerant enters from the first port of the third indoor heat exchanger, exchanges heat with the indoor air, and then is discharged from the second port. Since the refrigerant passes through the throttling of the first throttling element before entering the third indoor heat exchanger, the temperature of the refrigerant discharged from the third indoor heat exchanger is not very high, usually within 20°C or even within 10°C. When the system is abnormal, the refrigerant is discharged from the ejector's injection port and enters the third indoor heat exchanger from the second port of the third indoor heat exchanger. At this time, the refrigerant only passes through the ejector and does not pass through the throttling element, and the refrigerant temperature is basically above 20°C. Therefore, it can be determined whether the system is abnormal based on whether the temperature at the second end of the third indoor heat exchanger is greater than a preset temperature threshold (such as 20°C). Of course, the preset temperature threshold of 20°C is only exemplary, and those skilled in the art can adjust it based on the specific application scenario.

[0075] Next, referring to Figure 3 , in an alternative implementation, the control method of the heat pump system includes:

[0076] S201, obtain the pressure at the second end of the third indoor heat exchanger and the pressure at the first end of the first indoor heat exchanger. For example, when the system is operating in the refrigeration mode or the dehumidification mode, the pressure at the second end of the third indoor heat exchanger and the pressure at the first end of the first indoor heat exchanger are obtained by respectively arranging pressure sensors on the pipeline at the second end of the third indoor heat exchanger and the pipeline at the first end of the first indoor heat exchanger.

[0077] S203, based on the pressure at the second end and the pressure at the first end, determine whether the heat pump system is abnormal. For example, by calculating the difference between the pressure at the first end and the pressure at the second end and comparing the difference with a preset pressure difference threshold to determine whether the heat pump system is abnormal. For example, when the heat pump system is operating normally, the refrigerant flowing out from the second port ( Figure 1 left port) of the third indoor heat exchanger is introduced from the injection port and ejected from the outlet of the ejector to the first port ( Figure 1 left port) of the first indoor heat exchanger. Therefore, the pressure at the second end of the third indoor heat exchanger is less than the pressure at the first end of the first indoor heat exchanger, and the difference between the two is greater than the preset pressure difference threshold. When an abnormality occurs, the refrigerant is ejected from both the outlet of the ejector and the injection port. At this time, the pressure at the second port of the third indoor heat exchanger increases significantly, the difference between the pressure at the first end and the pressure at the second end decreases, and is less than the preset pressure difference threshold. Thus, after obtaining the pressure at the second end of the third indoor heat exchanger and the pressure at the first end of the first indoor heat exchanger, calculate the difference between the two, and based on whether the difference is greater than the preset pressure difference threshold, it can be determined whether the heat pump system is abnormal.

[0078] S205. When the heat pump system is abnormal, control the first valve body to open and the first throttling element to close. For example, when it is determined that the heat pump system is abnormal, control the first valve body to open and the first throttling element to close, and realize the refrigerant circulation by paralleling the first indoor heat exchanger and the second indoor heat exchanger.

[0079] Of course, the method of judging whether the heat pump system is abnormal by calculating the difference between the first-end pressure and the second-end pressure is only an example. Those skilled in the art can adjust it. For example, it can also be judged whether the heat pump system is abnormal by calculating the ratio of the two and comparing it with a preset ratio threshold. In addition, although the specific value of the above preset pressure difference threshold is not described in detail, this is not unclear. Those skilled in the art can determine it based on the specific application scenario.

[0080] The control method of the present application can judge whether the heat pump system is abnormal by comparing the first-port temperature of the first indoor heat exchanger with the second-end temperature of the third indoor heat exchanger, or by comparing the second-end temperature of the third indoor heat exchanger with a preset temperature difference threshold, or by comparing the second-end pressure of the third indoor heat exchanger with the first-end pressure of the first indoor heat exchanger. When the system is abnormal, ensure the normal operation of the system by timely switching the pipeline to ensure the user experience.

[0081] It should be noted that although the detailed steps of the method of the present application are described in detail above, without departing from the basic principle of the present application, those skilled in the art can combine, split and change the order of the above steps. The modified technical solution does not change the basic concept of the present application, so it also falls within the protection scope of the present application.

[0082] Those skilled in the art can also understand that although some of the embodiments described herein include certain features included in other embodiments rather than other features, the combination of the features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the claims of the present application, any one of the claimed embodiments can be used in any combination.

[0083] So far, the technical solution of the present application has been described in combination with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principle of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present application.

Claims

1. A heat pump system, characterized in that, The heat pump system includes a compressor, an outdoor heat exchanger, an ejector, a first indoor heat exchanger, a second indoor heat exchanger, a gas-liquid separator, a first throttling element, and a third indoor heat exchanger. The exhaust port of the compressor is communicated with the first port of the outdoor heat exchanger. The second port of the outdoor heat exchanger is communicated with the inlet of the ejector. The outlet of the ejector is communicated with the first port of the first indoor heat exchanger. The second port of the first indoor heat exchanger is communicated with the first port of the second indoor heat exchanger. The second port of the second indoor heat exchanger is communicated with the inlet of the gas-liquid separator. The exhaust port of the gas-liquid separator is communicated with the suction port of the compressor. The liquid discharge port of the gas-liquid separator is communicated with the first port of the first throttling element. The second port of the first throttling element is communicated with the first port of the third indoor heat exchanger. The second port of the third indoor heat exchanger is communicated with the injection port of the ejector. The heat pump system further includes a first bypass pipeline, a second bypass pipeline, and a first valve body. The first end of the first bypass pipeline is communicated between the second port of the third indoor heat exchanger and the injection port of the ejector, and the second end is communicated between the second port of the second indoor heat exchanger and the inlet of the gas-liquid separator. The first end of the second bypass pipeline is communicated between the second port of the first indoor heat exchanger and the first port of the second indoor heat exchanger, and the second end is communicated between the second end of the first bypass pipeline and the inlet of the gas-liquid separator. The first valve body is arranged on the second bypass pipeline.

2. The heat pump system according to claim 1, wherein, The heat pump system further includes a second valve body, and the second valve body is arranged between the second end of the first bypass pipeline and the second end of the second bypass pipeline.

3. The heat pump system according to claim 2, wherein The first valve body and / or the second valve body is an electromagnetic valve.

4. The heat pump system according to claim 2, wherein The heat pump system further includes a third valve body, and the third valve body is arranged on the first bypass pipeline.

5. The heat pump system according to claim 4, characterized in that, The third valve body is a check valve, and the check valve is configured to be conductive when the refrigerant flows from the first end to the second end of the first bypass pipeline.

6. The heat pump system according to claim 1, characterized in that, The heat pump system further includes a fourth valve body, and the fourth valve body is arranged between the first end of the first bypass pipeline and the injection port of the ejector.

7. The heat pump system according to claim 1, characterized in that, The heat pump system further includes a four-way valve. The four-way valve includes a first interface, a second interface, a third interface, and a fourth interface. The first interface is communicated with the exhaust port of the compressor. The second interface is communicated with the first port of the outdoor heat exchanger. The third interface is communicated with the suction port of the compressor. The fourth interface is communicated with the exhaust port of the gas-liquid separator.

8. The heat pump system according to claim 7, wherein, The heat pump system further includes a third bypass pipeline and a second throttling element. The first end of the third bypass pipeline is communicated between the outlet of the ejector and the first port of the first indoor heat exchanger, and the second end is communicated between the second port of the outdoor heat exchanger and the inlet of the ejector. The second throttling element is arranged on the third bypass pipeline.

9. The control method of the heat pump system according to claim 1, characterized in that, The area ratio of the first indoor heat exchanger to the second indoor heat exchanger is less than or equal to 1:

1.

10. A control method for a heat pump system according to any one of claims 1 to 9, characterized in that, The control method includes: Obtain the temperature at the first end of the first indoor heat exchanger and the temperature at the second end of the third indoor heat exchanger; Based on the temperature at the first end and the temperature at the second end, determine whether the heat pump system is abnormal; When the heat pump system is abnormal, control the first valve body to open and the first throttling element to close; or Obtain the pressure at the second end of the third indoor heat exchanger and the pressure at the first end of the first indoor heat exchanger; Based on the pressure at the second end and the pressure at the first end, determine whether the heat pump system is abnormal; When the heat pump system is abnormal, control the first valve body to open and the first throttling element to close; or Obtain the temperature at the second end of the third indoor heat exchanger; Based on the temperature at the second end and a preset temperature threshold, determine whether the heat pump system is abnormal; When the heat pump system is abnormal, control the first valve body to open and the first throttling element to close.

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