CN106958892B

CN106958892B - Air conditioner

Info

Publication number: CN106958892B
Application number: CN201710199202.7A
Authority: CN
Inventors: 杨俊�; 雷华翘
Original assignee: Midea Group Co Ltd; GD Midea Air Conditioning Equipment Co Ltd
Current assignee: Midea Group Co Ltd; GD Midea Air Conditioning Equipment Co Ltd
Priority date: 2017-03-29
Filing date: 2017-03-29
Publication date: 2020-05-05
Anticipated expiration: 2037-03-29
Also published as: CN106958892A

Abstract

The invention discloses an air conditioner, comprising: the low back pressure compressor comprises a shell with an oil pool and a cylinder, wherein the shell is provided with an exhaust port and a return air port, and the cylinder is arranged in the shell and provided with an exhaust channel and a suction channel; the reversing assembly is provided with a first valve port to a fourth valve port; the first end of the indoor heat exchanger is connected with the third valve port; the first end of the outdoor heat exchanger is connected with the second valve port, and a capillary tube assembly is connected in series between the second end of the outdoor heat exchanger and the second end of the indoor heat exchanger; the heat exchange piece is used for circulating a refrigerant, two ends of the heat exchange piece are respectively connected with the exhaust port and the exhaust channel, and at least part of the heat exchange piece is immersed in lubricating oil in the oil pool. According to the air conditioner of the invention, the oil temperature of the lubricating oil mixed in the refrigerant can be ensured not to be lower than the pour point temperature of the lubricating oil to a certain extent, so that the capillary of the capillary component can be prevented from being blocked to a certain extent.

Description

Air conditioner

Technical Field

The invention relates to the technical field of heat exchange, in particular to an air conditioner.

Background

Since the air conditioner using R290 as a refrigerant, particularly a heat pump air conditioner, is limited in the charge amount, the charge amount of the complete machine of the same capacity section is much smaller than that of the air conditioner using other refrigerants. In order to meet the requirements of cooling capacity and energy efficiency, the air conditioner needs to use a large-discharge compressor and a large-area heat exchanger.

When the air conditioner uses the capillary tube as a throttling device, when the defrosting is finished and the heating mode is switched, because the temperature at the capillary tube is lower than the pour point temperature of the lubricating oil of R290 for a long time, the lubricating oil can generate flocculent flow, and even block the capillary tube when the temperature is serious, so that the fault of the air conditioner is caused, and the use reliability of the air conditioner is reduced.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides an air conditioner which can prevent a capillary tube of a capillary tube component from being blocked to a certain extent, improve the use reliability of the air conditioner and reduce the failure rate of the air conditioner.

An air conditioner according to an embodiment of the present invention, which uses R290 as a refrigerant, includes: the low-backpressure compressor comprises a shell with an oil pool and a cylinder, wherein the shell is provided with an exhaust port and a return port, the cylinder is arranged in the shell and is provided with an exhaust channel and a suction channel, and the suction channel is connected with the return port; the reversing assembly is provided with a first valve port, a second valve port, a third valve port, a fourth valve port and a return port, wherein the first valve port is communicated with one of the second valve port and the third valve port in a switching mode, the fourth valve port is communicated with the other one of the second valve port and the third valve port in a switching mode, the first valve port is connected with the exhaust port, and the fourth valve port is connected with the return port; the first end of the indoor heat exchanger is connected with the third valve port; the first end of the outdoor heat exchanger is connected with the second valve port, and a capillary tube assembly is connected in series between the second end of the outdoor heat exchanger and the second end of the indoor heat exchanger; and the two ends of the heat exchange piece are respectively connected with the exhaust port and the exhaust channel, and at least part of the heat exchange piece is immersed in the lubricating oil in the oil pool.

According to the air conditioner provided by the embodiment of the invention, the lubricating oil in the oil pool is heated by utilizing the exhaust gas of the air cylinder, so that the oil temperature of the lubricating oil is improved, when the defrosting mode of the air conditioner is finished and is converted into the heating mode, the refrigerant flows out of the indoor heat exchanger and flows through the capillary tube of the capillary tube assembly, the oil temperature of the lubricating oil mixed in the refrigerant can be ensured to be not lower than the pour point temperature of the lubricating oil to a certain extent, the capillary tube of the capillary tube assembly can be prevented from being blocked to a certain extent, the failure rate of the air conditioner is reduced, the use reliability of the air conditioner is improved, and the service life of the air.

According to some embodiments of the invention, the heat exchange member is a heat exchange tube.

Optionally, the heat exchange tube is a coil.

Optionally, the heat exchange tube is a copper tube.

According to some embodiments of the invention, the reversing component is a four-way valve.

According to some embodiments of the invention, the air conditioner further comprises an accumulator connected in series between the return air port and the fourth valve port.

According to some embodiments of the present invention, the capillary tube assembly includes a first capillary tube, a second capillary tube, and a transition tube, a first end of the first capillary tube is connected to the second end of the indoor heat exchanger, a first end of the second capillary tube is connected to the second end of the outdoor heat exchanger, the transition tube is connected between the second end of the first capillary tube and the second end of the second capillary tube, an inner diameter of the transition tube is larger than inner diameters of the first capillary tube and the second capillary tube, and a length of the first capillary tube is not smaller than a length of the second capillary tube.

In particular, the length of the first capillary is greater than the length of the second capillary.

Specifically, the first capillary has a length L, and L satisfies: l is less than or equal to 700 mm.

Specifically, the transition pipe is horizontally disposed.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic diagram of an air conditioner according to some embodiments of the present invention;

fig. 2 is a schematic diagram of an air conditioner according to further embodiments of the present invention.

Reference numerals:

an air conditioner 100;

a low back pressure compressor 1; a housing 11; an exhaust port A; an air return port B; an oil sump 12;

a reversing component 2; a first valve port C; a second valve port D; a third port E; a fourth port F;

an indoor heat exchanger 3; an outdoor heat exchanger 4; a heat exchange member 5;

a capillary tube assembly 6; a first capillary 61; a transition tube 62; a second capillary 63.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "length," "upper," "lower," "left," "right," "horizontal," "top," "bottom," "inner," "outer," "radial," and the like are used in the orientations and positional relationships indicated in the drawings for the purpose of convenience and simplicity of description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, e.g., as being fixed or detachable or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1-2, an air conditioner 100 according to an embodiment of the present invention will be described, wherein the air conditioner 100 may use R290 as a refrigerant, and the air conditioner 100 may be used to adjust an indoor temperature, for example, the air conditioner 100 may be used to heat or cool an indoor environment. Alternatively, the air conditioner 100 may be a heat pump air conditioner, for example, the air conditioner 100 is a heat pump inverter air conditioner.

As shown in fig. 1 to 2, an air conditioner 100 according to an embodiment of the present invention may include a low back pressure compressor 1, a reversing assembly 2, an indoor heat exchanger 3, an outdoor heat exchanger 4, and a heat exchange member 5.

Specifically, as shown in fig. 1-2, the low back pressure compressor 1 includes a housing 11 and a compression mechanism (not shown) including a main bearing, a sub-bearing, a crankshaft, a cylinder, etc., the compression mechanism is disposed in the housing 11, an oil sump 12 is disposed in the housing 11, and lubricating oil is disposed in the oil sump 12, and when the compression mechanism operates, the lubricating oil can lubricate the compression mechanism, thereby improving the reliability of the operation of the compression mechanism.

The casing 11 has an exhaust port a and a return air port B, the cylinder has an exhaust passage and a suction passage, the suction passage is connected to the return air port B, the refrigerant after heat exchange can return to the cylinder of the low back pressure compressor 1 from the return air port B and the suction passage, the refrigerant can be compressed in the cylinder to form a high temperature and high pressure refrigerant, and the refrigerant is discharged out of the low back pressure compressor 1 through the exhaust passage and the exhaust port a in sequence. Here, it is understood that since the lubricating oil lubricates the operation of the compression mechanism, a small amount of lubricating oil is inevitably mixed in the refrigerant discharged from the discharge port a, and thus, the refrigerant herein refers to a refrigerant mixed with a small amount of lubricating oil.

The reversing assembly 2 has a first port C in switching communication with one of the second and third ports D, E through a fourth port F in switching communication with the other of the second and third ports D, E. In other words, when the first port C communicates with the second port D, the fourth port F communicates with the third port E, and when the first port C communicates with the third port E, the fourth port F communicates with the second port D.

The first valve port C is connected to the exhaust port a, and the fourth valve port F is connected to the return port B, so that the reversing assembly 2 is connected to the refrigerant circuit of the air conditioner 100 to facilitate the circulation of the refrigerant.

Preferably, the direction changing assembly 2 is a four-way valve, when the direction changing assembly 2 is powered off, the first port C is communicated with the second port D, the fourth port F is communicated with the third port E, when the direction changing assembly 2 is powered on, the first port C is communicated with the third port E, and the fourth port F is communicated with the second port D. It is understood that the reversing assembly 2 can be formed as other elements as long as the first valve port C to the fourth valve port F are provided and the reversing can be realized.

Since the first port C of the reversing assembly 2 can be in reversing communication with one of the second port D and the third port E, and the fourth port F is in reversing communication with the other of the second port D and the third port E to realize reversing, the air conditioner 100 can be switched between the cooling mode and the heating mode, so that the cooling function and the heating function of the air conditioner 100 are realized.

A first end (e.g., a left end shown in fig. 1 and 2) of the indoor heat exchanger 3 is connected to the third valve port E, a first end (e.g., a left end shown in fig. 1 and 2) of the outdoor heat exchanger 4 is connected to the second valve port D, and a capillary tube assembly 6 is connected in series between a second end (e.g., a right end shown in fig. 1 and 2) of the outdoor heat exchanger 4 and a second end (e.g., a right end shown in fig. 1 and 2) of the indoor heat exchanger 3, and the capillary tube assembly 6 can throttle and depressurize the refrigerant in the refrigerant flow path. For example, as shown in FIG. 1, the capillary assembly 6 is a capillary tube.

The heat exchange member 5 is connected at both ends thereof to the discharge port a and the discharge passage, respectively, and the heat exchange member 5 is at least partially immersed in the lubricating oil in the oil sump 12, whereby the refrigerant compressed by the cylinder can first flow toward the heat exchange member 5 after being discharged from the discharge passage, the refrigerant exchanges heat with the lubricating oil in the oil sump 12 in the heat exchange member 5 to heat the lubricating oil, and then the refrigerant is discharged from the discharge port a out of the low back pressure compressor 1.

Specifically, as shown in fig. 1 and 2, when the air conditioner 100 is in a cooling mode or a defrosting mode, the first valve port C of the reversing assembly 2 is communicated with the second valve port D, the third valve port E is communicated with the fourth valve port F, a high-temperature and high-pressure refrigerant compressed by the cylinder of the low-back-pressure compressor 1 can flow to the heat exchanging element 5 through the exhaust passage, the refrigerant performs primary heat exchange with the lubricating oil in the oil sump 12 in the heat exchanging element 5, the high-temperature and high-pressure refrigerant after heat exchange flows out of the heat exchanging element 5 and then flows to the first valve port C of the reversing assembly 2 through the exhaust port a, the refrigerant enters the outdoor heat exchanger 4 through the second valve port D of the reversing assembly 2 and performs energy exchange with the external environment in the outdoor heat exchanger 4, the refrigerant after flowing out of the outdoor heat exchanger 4 flows to the capillary tube assembly 6, and the refrigerant is throttled and depressurized by the capillary tube assembly 6 to, and then, the refrigerant enters the indoor heat exchanger 3 to absorb heat in the room and reduce the ambient temperature in the room, and the refrigerant flowing out of the indoor heat exchanger 3 returns to the cylinder of the low back pressure compressor 1 through the third valve port E and the fourth valve port F and through the return air port B and the suction air passage of the low back pressure compressor 1, thereby forming a refrigeration cycle, thereby reciprocating.

As shown in fig. 1 and 2, when the air conditioner 100 is in a heating mode, the first valve port C of the reversing component 2 is communicated with the third valve port E, the fourth valve port F is communicated with the second valve port D, the high-temperature and high-pressure refrigerant compressed by the cylinder of the low-backpressure compressor 1 flows to the heat exchanging component 5 through the exhaust passage, the refrigerant performs primary heat exchange with the lubricating oil in the oil pool 12 in the heat exchanging component 5, the high-temperature and high-pressure refrigerant after heat exchange is discharged from the exhaust port a, then flows into the indoor heat exchanger 3 through the first valve port C and the third valve port E, performs heat exchange with the indoor environment in the indoor heat exchanger 3, the refrigerant after heat exchange with the indoor heat exchanger 3 enters the capillary tube component 6, is throttled and depressurized by the capillary tube component 6 to form a low-temperature and low-pressure liquid refrigerant, and enters the outdoor heat exchanger 4, and exchanges heat with the outdoor environment in the, the refrigerant after heat exchange with the outdoor heat exchanger 4 flows through the second valve port D and the fourth valve port F and returns to the cylinder of the low back pressure compressor 1 through the return air port B and the suction passage of the low back pressure compressor 1, thereby reciprocating, and forming a heating cycle of the air conditioner 100.

In summary, no matter which operation mode the air conditioner 100 is in, the refrigerant discharged from the exhaust passage of the cylinder first flows through the heat exchanging element 5, so that the refrigerant in the heat exchanging element 5 can heat the lubricating oil in the oil pool 12, thereby increasing the oil temperature of the lubricating oil in the oil pool 12, and thus when the defrosting mode of the air conditioner 100 is finished and converted into the heating mode, when the refrigerant flows out of the indoor heat exchanger 3 and flows through the capillary tube of the capillary tube assembly 6, the oil temperature of the lubricating oil mixed in the refrigerant can be ensured to be not lower than the pour point temperature thereof to a certain extent, thereby preventing the capillary tube of the capillary tube assembly 6 from being blocked to a certain extent, reducing the failure rate of the air conditioner 100, increasing the reliability of the use of the air conditioner 100, and prolonging the service life of the air conditioner 100.

According to the air conditioner 100 of the embodiment of the invention, the lubricating oil in the oil pool 12 is heated by utilizing the exhaust gas of the cylinder, so that the oil temperature of the lubricating oil is improved, when the defrosting mode of the air conditioner 100 is converted into the heating mode, and the refrigerant flows out of the indoor heat exchanger 3 and flows through the capillary tube of the capillary tube assembly 6, the oil temperature of the lubricating oil mixed in the refrigerant can be ensured to be not lower than the pour point temperature to a certain extent, so that the capillary tube of the capillary tube assembly 6 can be prevented from being blocked to a certain extent, the failure rate of the air conditioner 100 is reduced, the use reliability of the air conditioner 100 is improved, and the service life of the air conditioner 100 is prolonged.

In some embodiments of the present invention, the heat exchange member 5 is a heat exchange tube, for example, the heat exchange member 5 is a coil, a flat tube, or the like. Of course, it is understood that the heat exchanger 5 may be formed in other structures, for example, the heat exchanger 5 is a heat exchanger, as long as the heat exchanger 5 can circulate the refrigerant and can realize the heat exchange between the refrigerant and the lubricating oil.

Preferably, the heat exchange tube is a copper tube, so that the heat exchange tube has good heat conduction performance and high heat exchange efficiency.

According to some embodiments of the present invention, the air conditioner 100 further includes an accumulator (not shown) connected in series between the return air port B and the fourth valve port F. Therefore, the refrigerant after heat exchange can flow to the reservoir after flowing out of the fourth valve port F, the liquid refrigerant in the refrigerant flowing into the reservoir can be stored in the reservoir, and the gaseous refrigerant can return to the low back pressure compressor 1 through the gas return port B, which not only facilitates the adjustment of the refrigerant flow in the refrigerant flow path, but also prevents the low back pressure compressor 1 from liquid impact.

In some embodiments of the present invention, as shown in fig. 2, the capillary tube assembly 6 includes a first capillary tube 61, a second capillary tube 63, and a transition tube 62, a first end (e.g., a lower end shown in fig. 2) of the first capillary tube 61 being connected to a second end of the indoor heat exchanger 3, a first end (e.g., an upper end shown in fig. 2) of the second capillary tube 63 being connected to a second end of the outdoor heat exchanger 4, and the transition tube 62 being connected between a second end (e.g., an upper end shown in fig. 2) of the first capillary tube 61 and a second end (e.g., a lower end shown in fig. 2) of the second capillary tube 63, whereby, when the air conditioner 100 is in the cooling mode or the defrosting mode, the refrigerant flowing from the outdoor heat exchanger 4 flows to the indoor heat exchanger 3 through the second capillary tube 63, the transition tube 62, and the first capillary tube; when the air conditioner 100 is in the heating mode, the refrigerant flowing out of the indoor heat exchanger 3 flows to the outdoor heat exchanger 4 through the first capillary tube 61, the transition tube 62, and the second capillary tube 63 in this order.

Specifically, the inner diameter of the transition tube 62 is larger than the inner diameters of the first and second

capillary tubes

61 and 63, that is, the inner diameter of the transition tube 62 is larger than the inner diameter of the first capillary tube 61 and the inner diameter of the transition tube 62 is larger than the inner diameter of the second capillary tube 63. For example, the inner diameters of the first and second

capillary tubes

61 and 63 are the same, and the inner diameter of the transition tube 62 is larger than the inner diameters of the first and second

capillary tubes

61 and 63.

The length of the first capillary 61 is not less than the length of the second capillary 63. That is, the length of the second capillary 63 is not greater than the length of the first capillary 61. For example, the length of the first capillary 61 is greater than the length of the second capillary 63. As another example, the length of the first capillary 61 is equal to the length of the second capillary 63.

Specifically, the temperature characteristic of the refrigerant in the capillary tube region is that the temperature of the refrigerant is substantially constant during the process from entering the capillary tube to exiting the capillary tube, and the temperature of the refrigerant begins to decrease rapidly (i.e., drop off) when the refrigerant reaches a certain distance through the capillary tube.

According to the air conditioner of the embodiment of the present invention, by replacing one capillary tube in the related art with the capillary tube assembly 6, so that the lengths of the first capillary tube 61 and the second capillary tube 63 are smaller than the length of the one capillary tube, during the process that the refrigerant flows from the first capillary tube 61 to the transition tube 62 when the defrosting mode of the air conditioner 100 is finished to the heating mode, it is beneficial to ensure that the temperature of the refrigerant in the first capillary tube 61 is in a substantially constant state, i.e., to ensure that the refrigerant enters the transition tube 62 before the temperature of the refrigerant is suddenly reduced, so that the generation of the flocculent flow due to the fact that the temperature of the lubricating oil in the refrigerant is lower than the pour point temperature of the lubricating oil can be avoided to some extent.

To put it back, even if the temperature of the refrigerant drops sharply in the first capillary tube 61 so that the lubricant in the refrigerant generates a flocculent flow in the first capillary tube 61, the flocculent flow can easily flow into the transition tube 62 and be temporarily stored in the transition tube 62 because the inner diameter of the transition tube 62 is larger than the inner diameters of the first capillary tube 61 and the second capillary tube 63, and the temperature of the refrigerant in the transition tube 62 is slightly increased because the transition tube 62 has no throttling and depressurizing effect or has a small throttling and depressurizing effect (for example, the transition tube 62 is a non-capillary tube), which helps the lubricant in the transition tube 62 to increase the temperature, so that the temperature of the lubricant is higher than the pour point temperature, and the risk of the lubricant blocking the second capillary tube 63 when the refrigerant in the transition tube 62 flows from the transition tube 62 to the second capillary tube 63 is also reduced.

Further, since the length of the second capillary 63 is not greater than the length of the first capillary 61, the length of the second capillary 63 can be shortened on the basis of not influencing throttling and pressure reduction of the refrigerant, which is beneficial to preventing lubricating oil in the refrigerant from generating flocculent flow in the second capillary 63, and further preventing the second capillary 63 from being blocked.

In short, according to the air conditioner 100 of the embodiment of the present invention, by making the capillary tube assembly 6 include the first capillary tube 61, the second capillary tube 63 and the transition tube 62, and making the inner diameter of the transition tube 62 larger than the inner diameters of the first capillary tube 61 and the second capillary tube 63, and making the length of the first capillary tube 61 not smaller than the length of the second capillary tube 63, it is beneficial to ensure that the temperature of the lubricating oil is higher than the pour point temperature of the lubricating oil after the refrigerant flows out of the indoor heat exchanger 3 when the defrosting mode of the air conditioner 100 is switched to the heating mode, so that the first capillary tube 61 and the second capillary tube 63 can be prevented from being blocked, the failure rate of the air conditioner 100 can be reduced, the reliability of the use of the air conditioner 100 can be improved, and the service life of the.

Preferably, the length of the first capillary 61 is greater than the length of the second capillary 63. Therefore, the length of the second capillary tube 63 is further limited, the flowing distance of the refrigerant in the second capillary tube 63 is shortened, and the risk that the second capillary tube 63 is blocked by the lubricating oil in the refrigerant when the defrosting mode of the air conditioner 100 is switched to the heating mode is further reduced.

In order to further avoid the clogging of the first capillary tube 61 by the lubricant oil in the refrigerant when the defrosting mode of the air conditioner 100 is finished to the heating mode, the length L of the first capillary tube 61 may be defined as: l is less than or equal to 700 mm. It is understood that when the length L of the first capillary 61 satisfies: when L is 700mm or less, the length of the second capillary 63 is 700mm or less and the length of the second capillary 63 is not more than the length of the first capillary 61. For example, when the length of the first capillary 61 is 690mm, the length of the second capillary 63 may be 650mm, 600mm, 620mm, or the like. As another example, when the length of the first capillary 61 is 650mm, the length of the second capillary 63 may be 550mm, 580mm, or 630 mm. Therefore, it is beneficial to further avoid the temperature of the refrigerant from dropping sharply in the first capillary tube 61 or the second capillary tube 63 when the defrosting mode of the air conditioner 100 is switched to the heating mode, and further avoid the lubricating oil from forming a flocculent flow.

In some further embodiments of the present invention, the transition pipe 62 is horizontally disposed, by horizontally disposing the transition pipe 62, the circulation speed of the refrigerant in the transition pipe 62 can be greatly reduced, thereby prolonging the circulation time of the refrigerant in the transition pipe 62, which facilitates further temperature rise of the lubricating oil in the transition pipe 62 and avoids blocking the second capillary tube 63 by the flocculent flow when the defrosting mode of the air conditioner 100 is switched to the heating mode, of course, the present invention is not limited thereto, and the transition pipe 62 can also be obliquely disposed, for example, the angle between the extending direction of the transition pipe 62 and the horizontal plane is α, which satisfies 0 ° < α ≦ 90 °, for example, α is 15 °, 20 °, 30 °, 60 °, or 45 °.

According to some examples of the invention, the transition tube 62 has an inner diameter d1, the first and second

capillary tubes

61 and 63 have an inner diameter d2, and d1 and d2 satisfy: d1 is more than or equal to 4mm, d2 is less than or equal to 2.1 mm. Therefore, when the defrosting mode of the air conditioner 100 is changed into the heating mode, the flocculent flow generated in the first capillary tube 61 and the second capillary tube 63 is further avoided, so that the first capillary tube 61 and the second capillary tube 63 are further prevented from being blocked, the failure rate of the air conditioner 100 is further reduced, the use reliability of the air conditioner 100 is improved, and the service life of the air conditioner 100 is prolonged.

Optionally, d1 is more than or equal to 5.5mm, and d2 is less than or equal to 2.0 mm. Furthermore, d1 is more than or equal to 6mm, and d2 is less than or equal to 1.5 mm. More preferably, d1 is more than or equal to 6mm, and d2 is less than or equal to 1.0 mm.

Optionally, the first capillary 61, the transition tube 62 and the second capillary 63 are one piece. Therefore, the structure is simple, the production process of the capillary assembly 6 can be simplified, the production cost can be reduced, and the installation process of the capillary assembly 6 in the air conditioner 100 can be simplified.

Preferably, the transition tube 62 is a copper tube. Therefore, the heat exchange efficiency of the copper pipe and the surrounding environment is improved, and the risk that the oil temperature of the lubricating oil at the transition pipe 62 is lower than the pour point temperature is further reduced.

In the description herein, references to the description of the term "some embodiments," "examples," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. An air conditioner using R290 as a refrigerant, comprising:

the low-backpressure compressor comprises a shell with an oil pool and a cylinder, wherein the shell is provided with an exhaust port and a return port, the cylinder is arranged in the shell and is provided with an exhaust channel and a suction channel, and the suction channel is connected with the return port;

the reversing assembly is provided with a first valve port, a second valve port, a third valve port, a fourth valve port and a return port, wherein the first valve port is communicated with one of the second valve port and the third valve port in a switching mode, the fourth valve port is communicated with the other one of the second valve port and the third valve port in a switching mode, the first valve port is connected with the exhaust port, and the fourth valve port is connected with the return port;

the first end of the indoor heat exchanger is connected with the third valve port;

an outdoor heat exchanger, a first end of the outdoor heat exchanger is connected with the second valve port, a capillary tube assembly is connected in series between a second end of the outdoor heat exchanger and a second end of the indoor heat exchanger, the capillary tube assembly comprises a first capillary tube, a second capillary tube and a transition tube, the first end of the first capillary tube is connected with the second end of the indoor heat exchanger, the first end of the second capillary tube is connected with the second end of the outdoor heat exchanger, the transition tube is connected between the second end of the first capillary tube and the second end of the second capillary tube, the inner diameter of the transition tube is larger than the inner diameters of the first capillary tube and the second capillary tube, the length of the first capillary tube is not smaller than the length of the second capillary tube, the inner diameter of the transition tube is d1, and the inner diameters of the first capillary tube and the second capillary tube are d2, the d1 and the d2 satisfy: d1 is more than or equal to 5.5mm, d2 is less than or equal to 2.0mm, and the transition pipe is horizontally arranged;

the heat exchange piece is used for circulating a refrigerant, two ends of the heat exchange piece are respectively connected with the exhaust port and the exhaust channel, at least part of the heat exchange piece is immersed in lubricating oil in the oil pool, and the heat exchange piece is a heat exchanger.

2. The air conditioner of claim 1, wherein the reversing component is a four-way valve.

3. The air conditioner of claim 1, further comprising an accumulator connected in series between the return air port and the fourth valve port.

4. The air conditioner of claim 1, wherein the length of the first capillary tube is greater than the length of the second capillary tube.

5. The air conditioner of claim 1, wherein the first capillary tube has a length L, wherein L satisfies: l is less than or equal to 700 mm.