Refrigerant circulating system and air conditioner

Abstract

The utility model relates to the technical field of air conditioners, and discloses a refrigerant circulating system and an air conditioner, the refrigerant circulating system comprises an indoor unit, an outdoor unit and a valve unit; the indoor unit comprises an indoor unit; the outdoor unit comprises a compressor, an extension pipe, a first pipeline, a second pipeline, a first outdoor heat exchanger, a third pipeline, a fourth pipeline, a gas-liquid separator, a fifth pipeline and a second outdoor heat exchanger; the valve unit comprises a first valve, a second valve, a third valve, a fourth valve and a fifth valve; according to the refrigerant circulation system, through the fifth pipeline, the second outdoor heat exchanger, the third valve, the fourth valve and the fifth valve, internal circulation of the refrigerant in the outdoor unit can be achieved, the circulation path of the refrigerant is shortened, the temperature of the refrigerant is rapidly increased, the refrigerant is separated from engine oil, sufficient lubrication is provided for a compressor, and the service life of the compressor is prolonged. Mechanical noise is reduced; and the service life of the compressor is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of air conditioning technology, and in particular to a refrigerant circulation system and an air conditioner. Background Technology

[0002] A significant problem exists in existing refrigerant circulation systems: during the initial compressor startup, a large amount of the oil-refrigerant mixture is discharged from the compressor body. Because the indoor and outdoor units are connected by long pipes, the refrigerant and oil discharged from the outdoor unit's compressor must travel through these long pipes into the indoor unit before circulating back to the outdoor unit's compressor. This process makes it difficult for the discharged oil to return to the compressor quickly. Furthermore, the refrigerant experiences significant energy loss during its long circulation path, resulting in a lower refrigerant temperature. The lower temperature of the refrigerant increases its miscibility with the oil, causing excessive dilution of the oil within the compressor body, leading to a significant decrease in oil concentration. When the refrigerant concentration in the oil is too high, the lubricating film thickness of the compressor's components (such as bearings and vanes) decreases due to the reduced oil viscosity during operation, potentially causing localized dry friction. This results in abnormal wear, increased mechanical noise, and a shortened lifespan.

[0003] While existing technologies exist to improve oil concentration by optimizing oil return control or using electric heating bands to wrap the compressor, these methods generally have limitations such as slow response speed, high energy consumption, or complex structure. They cannot quickly restore the concentration of refrigeration oil under transient conditions such as low-temperature start-up or defrosting, which means that the reliability of the system still faces challenges. Utility Model Content

[0004] With the aim of at least solving one of the technical problems existing in the prior art, this utility model aims to provide a refrigerant circulation system and an air conditioner having the refrigerant circulation system, which helps to reduce mechanical noise and extend the service life of the compressor, and improve the reliability of the system.

[0005] To achieve the above objectives, this utility model provides a refrigerant circulation system, including an indoor unit, an outdoor unit, and a valve unit. The indoor unit includes an indoor unit; the outdoor unit includes a compressor, an extended pipe, a first pipe, a second pipe, a first outdoor heat exchanger, a third pipe, a fourth pipe, a gas-liquid separator, a fifth pipe, and a second outdoor heat exchanger. The inlet end of the extended pipe is connected to the compressor, and the outlet end of the extended pipe is connected to the inlet end of the first pipe. The outlet end of the first pipe is connected to the indoor unit, and the inlet end of the second pipe is connected to the indoor unit. The first outdoor heat exchanger is installed on the second pipe, and the outlet end of the second pipe is connected to the inlet end of the third pipe. The outlet end of the third pipe is connected to the gas-liquid separator, and the inlet end of the fourth pipe is connected to the gas-liquid separator. The first outdoor unit is connected to the gas-liquid separator, the outlet end of the fourth pipe is connected to the compressor, the inlet end of the fifth pipe is connected to the extended tube, and the outlet end of the fifth pipe is connected to the gas-liquid separator. The second outdoor heat exchanger is installed on the fifth pipe. The valve unit includes a first valve, a second valve, a third valve, a fourth valve, and a fifth valve. The first valve is installed on the first pipe, the second valve is installed on the second pipe and located between the first outdoor heat exchanger and the indoor unit, the third valve is installed on the extended tube, the inlet end of the fifth pipe is located between the third valve and the compressor, the fourth valve and the fifth valve are installed sequentially on the fifth pipe, and the second outdoor heat exchanger is located between the fourth valve and the fifth valve.

[0006] In some implementations, the second outdoor heat exchanger is an air-cooled heat exchanger.

[0007] In some embodiments, the outdoor unit further includes a sixth pipe and a seventh pipe, the inlet end of the sixth pipe being connected to the fourth pipe and the outlet end of the sixth pipe being connected to the second outdoor heat exchanger, the inlet end of the seventh pipe being connected to the second outdoor heat exchanger and the outlet end of the seventh pipe being connected to the fourth pipe; the valve unit further includes a sixth valve, a seventh valve and an eighth valve, the sixth valve being installed on the sixth pipe, the seventh valve being installed on the seventh pipe, the eighth valve being installed on the fourth pipe, the inlet end of the sixth pipe being located between the eighth valve and the gas-liquid separator, and the outlet end of the seventh pipe being located between the eighth valve and the compressor.

[0008] In some implementations, the first outdoor heat exchanger is an air-cooled heat exchanger, and the second outdoor heat exchanger is a shell-and-tube heat exchanger or a plate heat exchanger.

[0009] In some embodiments, the outdoor unit further includes a throttling device installed in the second pipe and located between the second valve and the first outdoor heat exchanger.

[0010] In some embodiments, the throttling device is a throttling valve.

[0011] In some embodiments, the refrigerant circulation system further includes a first long connecting pipe and a second long connecting pipe, wherein the outlet end of the first pipe is connected to the indoor unit through the first long connecting pipe, and the inlet end of the second pipe is connected to the indoor unit through the second long connecting pipe.

[0012] In some embodiments, the refrigerant circulation system further includes a four-way valve, wherein the first valve port of the four-way valve is connected to the extended pipe, the second valve port of the four-way valve is connected to the inlet end of the first pipe, the third valve port of the four-way valve is connected to the outlet end of the second pipe, and the fourth valve port of the four-way valve is connected to the inlet end of the third pipe.

[0013] In some embodiments, the refrigerant circulation system further includes an oil separator and an oil return capillary tube, the oil separator being installed on the extension tube of the compressor, the inlet end of the oil return capillary tube being connected to the oil separator, and the outlet end of the oil return capillary tube being connected to the fourth pipe.

[0014] In some embodiments, the refrigerant circulation system further includes a silencer installed in the first duct.

[0015] Optionally, the number of compressors may be one or more.

[0016] Optionally, the compressor is a rotary compressor or a scroll compressor.

[0017] In some embodiments, the refrigerant circulation system further includes a bypass unit, which includes a bypass main pipe and a bypass main valve. The bypass main valve is installed on the bypass main pipe, the inlet end of the bypass main pipe is connected to the third pipe, and the outlet end of the bypass main pipe is connected to the compressor.

[0018] In some embodiments, the number of compressors is multiple; the bypass unit also includes multiple bypass branch pipes and multiple bypass branch valves, with one bypass branch valve installed on each bypass branch pipe, and the bypass main pipe is connected to multiple compressors one by one through multiple bypass branch pipes.

[0019] This utility model also provides an air conditioner, which includes a refrigerant circulation system according to any one of the above claims.

[0020] Compared with the prior art, the refrigerant circulation system of this utility model has the following advantages: (1) When the compressor is started under low temperature conditions or defrosting conditions, the third valve can be closed and the fourth and fifth valves can be opened so that the refrigerant from the compressor can directly reach the fifth pipe through the extension pipe without passing through the first pipe and the indoor unit. The refrigerant passes through the second outdoor heat exchanger and the throttling device through the fifth pipe to the gas-liquid separator, and then returns to the compressor through the fourth pipe from the gas-liquid separator, realizing the internal circulation of the refrigerant in the outdoor unit. This can shorten the circulation path of the refrigerant and reduce the energy loss of the refrigerant during the flow process. The energy generated by the compressor is used to heat the refrigerant itself to raise the temperature of the refrigerant. After the temperature rises, the refrigerant separates from the oil. The separated oil is more likely to be deposited at the bottom of the compressor and provide sufficient lubrication for the movement of the compressor's core components. This can prevent abnormal wear of the compressor's core components, help reduce mechanical noise and extend the service life of the compressor.

[0021] (2) Compared with the existing technology, which improves oil concentration by optimizing oil return control or using electric heating, the refrigerant circulation system provided by this utility model can quickly adjust the refrigerant circulation path through simple valve control. Under transient conditions such as low temperature start-up or defrosting, it can quickly restore the concentration of refrigeration oil, with a faster response speed. It does not require complex control logic and additional high-energy-consuming equipment, which simplifies the system structure, reduces the complexity and failure points of the system, helps to reduce equipment costs and maintenance costs, and improves the reliability and economy of the system. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a refrigerant circulation system provided in Embodiment 1 of this utility model;

[0023] Figure 2 This is a connection diagram of the outdoor unit and the valve unit provided in Embodiment 1 of this utility model;

[0024] Figure 3 This is a schematic diagram showing the connection between the outdoor unit and the bypass unit provided in Embodiment 1 of this utility model;

[0025] Figure 4 This is a schematic diagram of the structure of a refrigerant circulation system provided in Embodiment 2 of this utility model;

[0026] Figure 5 This is a schematic diagram showing the connection between the outdoor unit and the valve unit provided in Embodiment 2 of this utility model.

[0027] In the diagram, 1 is the indoor unit; 11 is the indoor unit.

[0028] 2. Outdoor unit; 21. Compressor; 22. Throttling device; 23. First outdoor heat exchanger; 24. Gas-liquid separator; 25. Second outdoor heat exchanger; 211. Extension tube;

[0029] 201. First pipeline; 202. Second pipeline; 203. Third pipeline; 204. Fourth pipeline; 205. Fifth pipeline; 206. Sixth pipeline; 207. Seventh pipeline;

[0030] 3. Valve Unit; 301. First Valve; 302. Second Valve; 303. Third Valve; 304. Fourth Valve; 305. Fifth Valve; 306. Sixth Valve; 307. Seventh Valve; 308. Eighth Valve;

[0031] 4. First longest connecting pipe;

[0032] 5. Second longest connecting pipe;

[0033] 6. Four-way valve;

[0034] 7. Bypass unit; 71. Bypass main pipe; 72. Bypass main valve; 73. Bypass branch pipe; 74. Bypass branch valve;

[0035] 8. Oil separator; 81. Oil return capillary tube;

[0036] 9. Muffler. Detailed Implementation

[0037] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0038] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0039] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0040] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having" and any variations thereof in the description, claims and foregoing drawings of this application are intended to cover non-exclusive inclusion.

[0043] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0044] Example 1

[0045] like Figures 1-3 As shown, the first embodiment of this utility model provides a refrigerant circulation system and air conditioner, including an indoor unit 1, an outdoor unit 2 and a valve unit 3.

[0046] Indoor unit 1 includes indoor unit 11.

[0047] Outdoor unit 2 includes a compressor 21, an extension pipe 211, a first pipe 201, a second pipe 202, a first outdoor heat exchanger 23, a third pipe 203, a fourth pipe 204, a gas-liquid separator 24, a fifth pipe 205, a second outdoor heat exchanger 25, and a throttling device 22. The inlet end of the extension pipe 211 is connected to the compressor 21, and the outlet end of the extension pipe 211 is connected to the inlet end of the first pipe 201. The outlet end of the first pipe 201 is connected to the indoor unit 11, and the inlet end of the second pipe 202 is connected to the indoor unit 11. The first outdoor heat exchanger 23 is installed on the second pipe. 202, the outlet end of the second pipe 202 is connected to the inlet end of the third pipe 203, the outlet end of the third pipe 203 is connected to the gas-liquid separator 24, the inlet end of the fourth pipe 204 is connected to the gas-liquid separator 24, the outlet end of the fourth pipe 204 is connected to the compressor 21, the inlet end of the fifth pipe 205 is connected to the extension pipe 211, the outlet end of the fifth pipe 205 is connected to the gas-liquid separator 24, the second outdoor heat exchanger 25 is installed on the fifth pipe 205, and the throttling device 22 is installed on the fifth pipe 205 and located between the second outdoor heat exchanger 25 and the gas-liquid separator 24.

[0048] Valve unit 3 includes a first valve 301, a second valve 302, a third valve 303, a fourth valve 304, and a fifth valve 305. The first valve 301 is installed on the first pipe 201. The second valve 302 is installed on the second pipe 202 and is located between the first outdoor heat exchanger 23 and the indoor unit 11. The third valve 303 is installed on the extension pipe 211. The inlet end of the fifth pipe 205 is located between the third valve 303 and the compressor 21. The fourth valve 304 and the fifth valve 305 are installed sequentially on the fifth pipe 205. The second outdoor heat exchanger 25 is located between the fourth valve 304 and the fifth valve 305.

[0049] Based on this technical solution, when starting the compressor 21 under low-temperature conditions or defrosting conditions, the third valve 303 can be closed and the fourth valve 304 and the fifth valve 305 opened. This allows the refrigerant from the compressor 21 to directly reach the fifth pipe 205 through the extended pipe 211 without passing through the first pipe 201 and the indoor unit 1. The refrigerant then passes through the second outdoor heat exchanger 25 and the throttling device 22 through the fifth pipe 205 to reach the gas-liquid separator 24, and then returns to the compressor 21 from the gas-liquid separator 24 through the fourth pipe 204. This achieves internal circulation of the refrigerant in the outdoor unit 2, thereby shortening the refrigerant circulation path and reducing energy loss during the refrigerant flow. The energy generated by the compressor 21 is used to heat the refrigerant itself to raise its temperature. As the temperature rises, the refrigerant separates from the oil. The separated oil is more likely to deposit at the bottom of the compressor 21 and provide sufficient lubrication for the movement of the compressor 21's core components. This helps to prevent abnormal wear of the compressor 21's core components, reduces mechanical noise, and extends the service life of the compressor 21.

[0050] The compressor 21 performs work on the refrigerant circulating internally in the outdoor unit 2 at low temperatures, rapidly heating and activating most of the refrigerant. This causes the refrigerant and oil to separate due to the rapid temperature rise, allowing the oil to return to the compressor 21 and remain within it, preventing abnormal wear on the internal components. The controller calculates the superheat TdSH by detecting the exhaust temperature of the compressor 21. If TdSH > 10K, it indicates that the refrigerant is fully activated. The controller then opens the first valve 301, the second valve 302, and the third valve 303, and closes the fourth valve 304 and the fifth valve 305, switching the refrigerant circulation system to a large circulation process connecting the indoor unit 1 and the outdoor unit 2. If TdSH ≤ 10K occurs during the large circulation process connecting the indoor unit 1 and the outdoor unit 2, the third valve 303 is closed again, and the fourth valve 304 and the fifth valve 305 are opened, switching the refrigerant circulation system back to a small circulation process connecting the outdoor unit 2. This cycle is repeated several times to fully activate all the refrigerant.

[0051] Compared to existing technologies that improve oil concentration through optimized oil return control or electric heating, the refrigerant circulation system provided by this invention can quickly adjust the refrigerant circulation path through simple valve control. Under transient conditions such as low-temperature startup or defrosting, it can rapidly restore the concentration of the refrigeration oil, offering a faster response. It eliminates the need for complex control logic and additional high-energy-consuming equipment, simplifying the system structure, reducing system complexity and potential failure points, and helping to lower equipment and maintenance costs while improving system reliability and economy.

[0052] In this first embodiment, there are four indoor units 11, which are connected in parallel.

[0053] In some other implementations, the number of indoor units 11 can be any number, such as one, two, three, etc.

[0054] The indoor unit 11 is the terminal equipment in the entire air conditioning system that directly provides cooling or heating services to the indoor environment. The indoor unit 11 includes structures such as heat exchangers, throttling devices, and controllers.

[0055] Optionally, the compressor 21 is a rotary compressor or a scroll compressor.

[0056] Optionally, the number of compressors 21 may be one or more.

[0057] Optionally, when there are multiple compressors 21, any two compressors 21 can be of the same or different types; that is, all of the multiple compressors 21 can be rotary compressors, all of them can be scroll compressors, or some of the compressors 21 can be rotary compressors and the other part of the compressors 21 can be scroll compressors.

[0058] In this first embodiment, the outdoor unit also includes a throttling device 22, which is installed in the second pipe 202 and located between the second valve 302 and the first outdoor heat exchanger 23.

[0059] For example, in the embodiment, the throttling device 22 is a throttling valve, which can not only achieve throttling but also regulate the flow rate; for example, the throttling device 22 can also be configured as a capillary tube.

[0060] See Figure 1 The outdoor side of the frame enclosed by the dashed line refers to the equipment and components located outdoors within the frame; the indoor side of the frame enclosed by the dashed line refers to the equipment and components located indoors within the frame. Figures 1-3 The arrow on the pipe indicates the direction of fluid flow within that pipe.

[0061] In this first embodiment, the first valve 301, the second valve 302, the third valve 303, the fourth valve 304, and the fifth valve 305 are all regulating valves.

[0062] The outdoor unit 2 also includes a sixth pipe 206 and a seventh pipe 207. The inlet end of the sixth pipe 206 is connected to the fourth pipe 204, and the outlet end of the sixth pipe 206 is connected to the second outdoor heat exchanger 25. The inlet end of the seventh pipe 207 is connected to the second outdoor heat exchanger 25, and the outlet end of the seventh pipe 207 is connected to the fourth pipe 204.

[0063] Valve unit 3 also includes a sixth valve 306, a seventh valve 307, and an eighth valve 308. The sixth valve 306 is installed in the sixth pipe 206, the seventh valve 307 is installed in the seventh pipe 207, and the eighth valve 308 is installed in the fourth pipe 204. The inlet end of the sixth pipe 206 is located between the eighth valve 308 and the gas-liquid separator 24, and the outlet end of the seventh pipe 207 is located between the eighth valve 308 and the compressor 21.

[0064] By adding a sixth pipe 206, a seventh pipe 207, a sixth valve 306, a seventh valve 307, and an eighth valve 308, and by properly controlling the sixth valve 306, the refrigerant from the gas-liquid separator 24 can be guided into the fourth pipe 204 and then flow back to the second outdoor heat exchanger 25 through the fourth pipe 204 and the sixth pipe 206. From the second outdoor heat exchanger 25, it enters the seventh pipe 207 and then enters the compressor 21 through the seventh pipe 207 and the fourth pipe 204, thus regulating the state of the refrigerant entering the compressor 21.

[0065] Optionally, the first outdoor heat exchanger 23 may be, but is not limited to, an air-cooled heat exchanger, a plate heat exchanger, or a shell-and-tube heat exchanger.

[0066] In this first embodiment, the first outdoor heat exchanger 23 is an air-cooled heat exchanger.

[0067] Optionally, the second outdoor heat exchanger 25 may be, but is not limited to, an air-cooled heat exchanger, a plate heat exchanger, or a shell-and-tube heat exchanger.

[0068] In this first embodiment, the second outdoor heat exchanger 25 is a plate heat exchanger. The high-temperature, high-pressure refrigerant entering the second outdoor heat exchanger 25 from the fifth pipe 205 and the low-temperature, low-pressure refrigerant entering the second outdoor heat exchanger 26 from the sixth pipe 206 fully exchange heat in the second outdoor heat exchanger 25, causing the overall temperature of the refrigerant to rise rapidly. This allows the engine oil to separate out of the refrigerant and flow back to the compressor along with the refrigerant through the seventh pipe 307 and the fourth pipe 304, providing sufficient lubrication for the movement of the compressor 21's core components.

[0069] The refrigerant circulation system also includes a first long connecting pipe 4 and a second long connecting pipe 5. The outlet end of the first pipe 201 is connected to the indoor unit 11 through the first long connecting pipe 4, and the inlet end of the second pipe 202 is connected to the indoor unit 11 through the first long connecting pipe 4.

[0070] The first long connecting pipe 4 and the second long connecting pipe 5 are relatively long pipes connecting indoor unit 1 and outdoor unit 2. The first long connecting pipe 4 and the first pipe 201 can be different parts of a single integral pipe, or they can be two different pipes connected together. The second long connecting pipe 5 and the second pipe 202 can be different parts of a single integral pipe, or they can be two different pipes connected together.

[0071] The use of the first long connecting pipe 4 and the second long connecting pipe 5 makes the connection between the indoor unit 1 and the outdoor unit 2 more flexible. In actual installation scenarios, whether the indoor and outdoor units are far apart in large buildings or the complex spatial layout has special requirements for the pipe routing, the connection between the indoor unit 11 and the outdoor unit 2 can be easily achieved through these two long connecting pipes, meeting the needs of different installation environments and improving the applicability of the refrigerant circulation system.

[0072] The refrigerant circulation system also includes a four-way valve 6. The first port of the four-way valve 6 is connected to the extended pipe 211, the second port is connected to the inlet end of the first pipe 201, the third port is connected to the outlet end of the second pipe 202, and the fourth port is connected to the inlet end of the third pipe 203. Compared to using multiple valves or complex piping connections to achieve cooling and heating mode switching, the four-way valve 6 simplifies the overall structure of the refrigerant circulation system, reduces the number of pipes and valves, lowers system complexity and potential failure points, and also reduces installation costs and maintenance difficulty.

[0073] The refrigerant circulation system provided in this embodiment of the present invention also includes an oil separator 8 and an oil return capillary tube 81. The oil separator 8 is installed on the outer tube 211 of the compressor 21. The inlet end of the oil return capillary tube 81 is connected to the oil separator 8, and the outlet end of the oil return capillary tube 81 is connected to the fourth pipe 204. The oil separator 8 can collect the mixture of refrigerant and oil discharged from the compressor 21 and return the oil back to the compressor 21 through the oil return capillary tube 81 and the fourth pipe 204 in sequence. This further increases the oil concentration in the compressor 21, which helps to further avoid abnormal wear of the compressor 21's core components, reduce mechanical noise, and extend the service life of the compressor 21.

[0074] The refrigerant circulation system also includes a silencer 9, which is installed on the first pipe 201. The silencer 9, installed on the first pipe 201, effectively suppresses the noise generated by the high-speed flow of refrigerant within the pipe. During the operation of the refrigerant circulation system, after the refrigerant is discharged from the compressor 21, it passes through the first pipe 201 at high speed, generating significant airflow noise. The silencer 9, through its special structure and sound-absorbing materials, absorbs and converts this noise energy, thereby reducing the noise generated during the operation of the entire system and creating a quieter and more comfortable operating environment for users.

[0075] See Figure 1 and Figure 3 The refrigerant circulation system also includes a bypass unit 7, which includes a bypass main pipe 71 and a bypass main valve 72. The bypass main valve 72 is installed on the bypass main pipe 71. The inlet end of the bypass main pipe 71 is connected to the third pipe 203, and the outlet end of the bypass main pipe 71 is connected to the compressor 21.

[0076] The refrigerant circulation system operates under complex and variable conditions. By using the bypass unit 7, the refrigerant circulation system can be made more adaptable. When the ambient temperature changes or the system operating mode is switched, the refrigerant flow of the bypass main valve 72 can be adjusted to the bypass main pipe 71, which can quickly balance the system pressure and temperature, so that the system can quickly adapt to the new operating conditions, reduce large fluctuations in pressure and temperature, ensure that the system is always in a state of high efficiency, and improve the overall operating performance.

[0077] The number of compressors 21 is multiple; the bypass unit 7 also includes multiple bypass branch pipes 73 and multiple bypass branch valves 74. A bypass branch valve 74 is installed on each bypass branch pipe 73. The bypass main pipe 71 is connected to multiple compressors 21 one by one through multiple bypass branch pipes 73.

[0078] Multiple compressors 21, together with multiple bypass branch pipes 73 and bypass branch valves 74, can achieve precise and independent control of the refrigerant flow of each compressor 21. Under different operating conditions, such as when the cooling or heating demand of some areas is different, the amount of refrigerant entering each compressor 21 can be controlled by adjusting the corresponding bypass branch valves 74 according to actual needs, so that each compressor 21 can operate under the best operating conditions and improve the overall energy efficiency ratio of the system.

[0079] In this first embodiment, there are two compressors 21 connected in parallel.

[0080] In some other embodiments, the number of compressors 21 can also be any number, such as one, three, four, etc.

[0081] In this first embodiment, both the bypass main valve 72 and the bypass branch valve 74 are regulating valves.

[0082] Compared with the existing technology that uses an electric heating band to wrap the compressor casing to improve oil concentration (comparative example), the refrigerant circulation system provided in this embodiment has the following advantages as shown in Table 1:

[0083]

[0084] Table 1

[0085] In Table 1, the oil temperature heating power of 120W in the comparative example refers to the power of the electric heating belt, while the oil temperature heating power of 6000W in this embodiment refers to the sum of the power of the two compressors.

[0086] Example 2

[0087] See Figures 4-5 Unlike Embodiment 1, the second outdoor heat exchanger 25 of the refrigerant circulation system provided in Embodiment 2 is an air-cooled heat exchanger, and the refrigerant circulation system does not include the sixth pipe 206, the seventh pipe 207, the sixth valve 306, the seventh valve 307 and the eighth valve 308.

[0088] This utility model also provides an air conditioner, which includes the refrigerant circulation system described above.

[0089] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A refrigerant circulation system, characterized in that, include: Indoor unit (1), which includes indoor unit (11); An outdoor unit (2) includes a compressor (21), an extension tube (211), a first pipe (201), a second pipe (202), a first outdoor heat exchanger (23), a third pipe (203), a fourth pipe (204), a gas-liquid separator (24), a fifth pipe (205), and a second outdoor heat exchanger (25). The inlet end of the extension tube (211) is connected to the compressor (21), and the outlet end of the extension tube (211) is connected to the inlet end of the first pipe (201). The outlet end of the first pipe (201) is connected to the indoor unit (11), and the inlet end of the second pipe (202) is connected to the indoor unit (11). An outdoor heat exchanger (23) is installed on the second pipe (202), the outlet end of the second pipe (202) is connected to the inlet end of the third pipe (203), the outlet end of the third pipe (203) is connected to the gas-liquid separator (24), the inlet end of the fourth pipe (204) is connected to the gas-liquid separator (24), the outlet end of the fourth pipe (204) is connected to the compressor (21), the inlet end of the fifth pipe (205) is connected to the extension tube (211), the outlet end of the fifth pipe (205) is connected to the gas-liquid separator (24), and the second outdoor heat exchanger (25) is installed on the fifth pipe (205). The valve unit (3) includes a first valve (301), a second valve (302), a third valve (303), a fourth valve (304), and a fifth valve (305). The first valve (301) is installed on the first pipe (201). The second valve (302) is installed on the second pipe (202) and located between the first outdoor heat exchanger (23) and the indoor unit (11). The third valve (303) is installed on the extension pipe (211). The inlet end of the fifth pipe (205) is located between the third valve (303) and the compressor (21). The fourth valve (304) and the fifth valve (305) are installed sequentially on the fifth pipe (205). The second outdoor heat exchanger (25) is located between the fourth valve (304) and the fifth valve (305).

2. The refrigerant circulation system according to claim 1, characterized in that, The second outdoor heat exchanger (25) is an air-cooled heat exchanger.

3. The refrigerant circulation system according to claim 1, characterized in that, The outdoor unit (2) further includes a sixth pipe (206) and a seventh pipe (207). The inlet end of the sixth pipe (206) is connected to the fourth pipe (204), and the outlet end of the sixth pipe (206) is connected to the second outdoor heat exchanger (25). The inlet end of the seventh pipe (207) is connected to the second outdoor heat exchanger (25), and the outlet end of the seventh pipe (207) is connected to the fourth pipe (204). The valve unit (3) further includes a sixth valve (306), a seventh valve (307), and an eighth valve (308). The sixth valve (306) is installed in the sixth pipe (206), the seventh valve (307) is installed in the seventh pipe (207), and the eighth valve (308) is installed in the fourth pipe (204). The inlet end of the sixth pipe (206) is located between the eighth valve (308) and the gas-liquid separator (24), and the outlet end of the seventh pipe (207) is located between the eighth valve (308) and the compressor (21).

4. The refrigerant circulation system according to claim 3, characterized in that, The first outdoor heat exchanger (23) is an air-cooled heat exchanger, and the second outdoor heat exchanger (25) is a shell-and-tube heat exchanger or a plate heat exchanger.

5. The refrigerant circulation system according to claim 1, characterized in that, The outdoor unit (2) also includes a throttling device (22), which is installed on the second pipe (202) and located between the second valve (302) and the first outdoor heat exchanger (23).

6. The refrigerant circulation system according to claim 1, characterized in that, It also includes a first long connecting pipe (4), a second long connecting pipe (5) and a four-way valve (6). The outlet end of the first pipe (201) is connected to the indoor unit (11) through the first long connecting pipe (4), and the inlet end of the second pipe (202) is connected to the indoor unit (11) through the second long connecting pipe (5). The first valve port of the four-way valve (6) is connected to the extended pipe (211), the second valve port of the four-way valve (6) is connected to the inlet end of the first pipe (201), the third valve port of the four-way valve (6) is connected to the outlet end of the second pipe (202), and the fourth valve port of the four-way valve (6) is connected to the inlet end of the third pipe (203).

7. The refrigerant circulation system according to claim 1, characterized in that, It also includes an oil separator (8), an oil return capillary tube (81), and a muffler (9). The oil separator (8) is installed on the extension tube (211) of the compressor (21). The inlet end of the oil return capillary tube (81) is connected to the oil separator (8), and the outlet end of the oil return capillary tube (81) is connected to the fourth pipe (204). The muffler (9) is installed on the first pipe (201).

8. The refrigerant circulation system according to any one of claims 1-7, characterized in that, It also includes a bypass unit (7), which includes a bypass main pipe (71) and a bypass main valve (72). The bypass main valve (72) is installed on the bypass main pipe (71). The inlet end of the bypass main pipe (71) is connected to the third pipeline (203), and the outlet end of the bypass main pipe (71) is connected to the compressor (21).

9. The refrigerant circulation system according to claim 8, characterized in that, The number of compressors (21) is multiple; the bypass unit (7) also includes multiple bypass branch pipes (73) and multiple bypass branch valves (74), one bypass branch valve (74) is installed on one of the bypass branch pipes (73), and the bypass main pipe (71) is connected to the multiple compressors (21) one by one through the multiple bypass branch pipes (73).

10. An air conditioner, characterized in that, Includes the refrigerant circulation system according to any one of claims 1-9.

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