Outdoor unit and multi-connected system

Abstract

The application provides an outdoor unit and a multi-connected system, which comprises a compressor, a gas-liquid separator, an oil separator, a condenser, a four-way valve, a main liquid pipe and a main gas pipe, the gas-liquid separator is connected with the compressor, one end of the oil separator is connected with the compressor, the other end of the oil separator is connected with the gas-liquid separator, the condenser is connected with the compressor, the four-way valve is arranged between the condenser and the compressor, the four-way valve comprises four interfaces, and the four-way valve is connected with the compressor, the gas-liquid separator and the condenser respectively; one end of the main liquid pipe is connected with the condenser, and one end of the main gas pipe is connected with the four-way valve. The outdoor unit and the indoor unit form a refrigerant circuit to realize a refrigeration effect, the oil separator is connected with the exhaust side of the compressor, the oil separator is used for recovering lubricating oil from the refrigerant vapor discharged from the compressor, and the refrigerant vapor returns to the compressor, so that the compressor is prevented from being damaged due to oil shortage, the whole system structure is reasonable, and the performance and reliability of the multi-connected system are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of air conditioning technology, in particular to an outdoor unit and a multi-connected air conditioning system. BACKGROUND

[0002] Multi-connected air conditioning system is widely used, especially in small and medium-sized buildings and some public buildings, which has the advantages of low energy utilization efficiency, low operation cost, intelligent adjustment and precise temperature control function, and can meet the needs of different spaces and air conditioning load. However, in the current operation process of most multi-connected air conditioning systems, there are problems such as large pressure loss, poor oil return, and excessive noise, which further lead to substandard performance and reliability. SUMMARY

[0003] In view of the above problems existing in the prior art, the purpose of the present application is to provide an outdoor unit and a multi-connected air conditioning system. The refrigerant enters the gas-liquid separator from the main gas pipe, is compressed into high-temperature and high-pressure gaseous refrigerant after gas-liquid separation, is sent to the condenser to be cooled into liquid refrigerant, and the liquid refrigerant flows out from the main liquid pipe to form a refrigerant circuit with the indoor unit to realize the refrigeration effect. An oil separator is connected to the exhaust side of the compressor. The oil separator recovers lubricating oil from the refrigerant vapor discharged from the compressor, and returns to the compressor, thereby avoiding damage caused by lack of oil in the compressor. The whole system structure is reasonable, and the performance and reliability of the multi-connected air conditioning system are improved.

[0004] The technical scheme adopted by the present application is to provide an outdoor unit, comprising:

[0005] A compressor for compressing refrigerant into high-temperature and high-pressure gaseous refrigerant;

[0006] A gas-liquid separator connected to the compressor;

[0007] An oil separator, one end of which is connected to the compressor, and the other end is connected to the gas-liquid separator, the oil separator is used to separate lubricating oil in gaseous refrigerant;

[0008] A condenser connected to the compressor;

[0009] A four-way valve provided between the condenser and the compressor, the four-way valve includes four interfaces, and the four-way valve is connected to the compressor, the gas-liquid separator and the condenser respectively;

[0010] A main liquid pipe and a main gas pipe, one end of the main liquid pipe is connected to the condenser, and one end of the main gas pipe is connected to the four-way valve.

[0011] Compared with existing technologies, the technical effects achieved by this solution are as follows: The refrigerant enters the gas-liquid separator from the main gas pipe. After the gas-liquid separator separates the refrigerant into gas and liquid, it is compressed into a high-temperature, high-pressure gaseous refrigerant in the compressor. Then, it is sent to the condenser to be cooled into a liquid refrigerant. The liquid refrigerant flows out from the main liquid pipe, achieving the cooling effect. An oil separator is connected to the compressor discharge side. The oil separator is used to recover lubricating oil from the refrigerant vapor discharged from the compressor, thereby preventing the compressor from being damaged due to lack of oil and preventing oil droplets from depositing in other parts of the system, which would affect the heat exchange efficiency. The four-way valve is set to switch the flow direction of the refrigerant between cooling and heating modes.

[0012] In an optional embodiment, the ratio of the diameter of the main gas pipe to the diameter of the main liquid pipe is in the range of 1.6-2.

[0013] Compared with existing technologies, the technical effects achieved by adopting this technical solution are as follows: the ratio of the diameters of the main gas pipe and the main liquid pipe is within a reasonable range, which can effectively balance the pressure loss, oil return and noise of the multi-unit system while ensuring the performance and reliability of the unit.

[0014] In an optional implementation, when the air conditioner's horsepower is ≤12 horsepower, the diameter of the main liquid pipe of the outdoor unit ranges from 11.5 to 12.5 mm, and the diameter of the main gas pipe ranges from 18.8 to 23.8 mm; and / or

[0015] When the air conditioner's horsepower is between 12 and 22 horsepower, the diameter of the main liquid pipe of the outdoor unit ranges from 15.6 to 16.6 mm, and the diameter of the main gas pipe ranges from 25.5 to 31.5 mm; and / or

[0016] When the air conditioner's horsepower is greater than 22 horsepower, the diameter of the main liquid pipe of the outdoor unit ranges from 20.0 to 22.6 mm, and the diameter of the main gas pipe ranges from 32.6 to 42.9 mm.

[0017] Compared with existing technologies, the technical effects achieved by adopting this technical solution are as follows: through calculation and analysis, the pipe diameters of the main liquid pipe and the main gas pipe are controlled within a reasonable range, which can effectively balance the pressure loss, oil return and noise of the multi-unit system while ensuring the performance and reliability of the unit.

[0018] In an optional embodiment, a one-way valve and a first expansion valve are provided between the main liquid pipe and the condenser. The one-way valve and the first expansion valve are connected in parallel. The one-way valve has a fluid inlet end and a fluid outlet end, with the fluid inlet end facing the condenser and the fluid outlet end facing the main liquid pipe.

[0019] Compared with the prior art, the technical effects achieved by the technical scheme are that the one-way valve can control the refrigerant to flow from the condenser to the main liquid pipe, ensure that the refrigerant only flows in one direction, prevent the refrigerant from flowing back to the compressor after the compressor is turned off, avoid damage to the compressor due to the presence of liquid refrigerant when starting next time, and the first expansion valve can accurately control the flow of the refrigerant, thereby improving the energy efficiency and operation stability of the multi-split system.

[0020] In an optional embodiment, a supercooling and enthalpy injection pipeline is arranged between the main liquid pipe and the compressor, the supercooling and enthalpy injection pipeline is provided with a second expansion valve and a first electromagnetic valve, the supercooling and enthalpy injection pipeline has a branch pipeline connected to the gas-liquid separator, and the branch pipeline is provided with a second electromagnetic valve.

[0021] Compared with the prior art, the technical effects achieved by the technical scheme are that the supercooling and enthalpy injection pipeline can supercool the refrigerant before throttling in the main circulation loop, thereby improving the refrigerating capacity and improving the low-temperature operation stability, and the low-pressure and low-temperature refrigerant after pressure reduction by the second expansion valve can be appropriately preheated to achieve a suitable medium pressure, thereby providing the compressor for secondary compression and optimizing the performance of the refrigeration system.

[0022] In an optional embodiment, the outdoor unit further comprises an oil return capillary tube, one end of the oil return capillary tube is connected to the flow path of the oil separator and the gas-liquid separator, and the other end of the oil return capillary tube is connected to a maintenance valve, and the oil return capillary tube is used to store lubricating oil in the gas-liquid separator.

[0023] Compared with the prior art, the technical effects achieved by the technical scheme are that the oil return capillary tube can protect the compressor from wear and tear, and can also maintain stable operation of the system by adjusting the temperature and balancing the pressure, while protecting the system from damage by controlling the flow and pressure of the refrigerant.

[0024] In an optional embodiment, a high-pressure switch and a first pressure sensor are arranged between the compressor and the four-way valve, and the first pressure sensor is used to detect the high-pressure when the gas is out.

[0025] Compared with the prior art, the technical effects achieved by the technical scheme are that the high-pressure switch is a safety device for protecting the refrigeration cycle system from high-pressure damage, and is a pressure-sensitive automatic switch that will act when the pressure in the system exceeds the normal operating range, cutting off the power supply of the compressor or starting other protection mechanisms to prevent damage to the system; the first pressure sensor is located on the high-pressure side of the system and detects the pressure of the refrigerant on the high-pressure side to prevent the system pressure from being too high.

[0026] In an optional embodiment, a second pressure sensor is arranged between the gas-liquid separator and the four-way valve, and the second pressure sensor is used to detect the low-pressure when the gas is inhaled.

[0027] Compared with the prior art, the technical effects achieved by adopting the technical scheme are that the second pressure sensor is located at the low-pressure side of the system and is used for detecting the pressure at the low-pressure side, so as to ensure sufficient refrigerant flow and evaporation effect.

[0028] In an optional embodiment, an oil return pipeline is arranged between the oil separator and the gas-liquid separator, and an oil return valve is arranged on the oil return pipeline.

[0029] Compared with the prior art, the technical effects achieved by adopting the technical scheme are that the oil return valve arranged between the oil separator and the gas-liquid separator is used for ensuring that the compressor can obtain sufficient lubricating oil, avoiding wear of the compressor, and improving the oil return efficiency of the multi-split system.

[0030] The application further provides a multi-split system, which comprises the outdoor unit and the indoor unit according to any one of the above embodiments, the indoor unit is connected between the main liquid pipe and the main gas pipe, and the outdoor unit is connected with the indoor unit to form a refrigerant circuit.

[0031] Compared with the prior art, the technical effects achieved by adopting the technical scheme are that the multi-split system of the technical scheme of the application comprises the outdoor unit according to any one of the above embodiments, and thus has all the beneficial effects of the outdoor unit according to any one of the technical schemes of the application, which will not be described herein again.

[0032] In the multi-split system of the application, the refrigerant enters the gas-liquid separator from the main gas pipe, is compressed into high-temperature and high-pressure gaseous refrigerant in the compressor after gas-liquid separation, is sent to the condenser to be cooled into liquid refrigerant, and flows out from the main liquid pipe to form a refrigerant circuit with the indoor unit to achieve a refrigeration effect. The oil separator is connected at the exhaust side of the compressor, and is used for recovering lubricating oil from the refrigerant vapor discharged from the compressor to avoid damage of the compressor due to lack of oil. The whole system has a reasonable structure, improves the performance and reliability of the multi-split system, and effectively balances the pressure loss, oil return and noise of the multi-split system. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 FIG. 1 shows a structural schematic diagram of an outdoor unit according to an embodiment of the application;

[0034] Figure 2 FIG. 2 shows a flow direction schematic diagram of refrigerant according to an embodiment of the application.

[0035] Legend of reference signs:

[0036] 1. Compressor; 2. Gas-liquid separator; 3. Oil separator; 4. Condenser; 5. Four-way valve; 6. Main gas pipe; 7. Main liquid pipe; 8. Check valve; 9. First expansion valve; 10. Second expansion valve; 11. First solenoid valve; 12. Second solenoid valve; 13. Oil return capillary tube; 14. Inspection valve; 15. High-pressure switch; 16. First pressure sensor; 17. Second pressure sensor; 18. Oil return valve; 19. Needle valve; 20. Liquid storage tank. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0039] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0040] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0041] See appendix Figure 1 As shown, the present invention provides an outdoor unit, comprising:

[0042] Compressor 1, wherein the compressor 1 is used to compress a high-temperature, high-pressure gaseous refrigerant;

[0043] Gas-liquid separator 2, which is connected to compressor 1;

[0044] An oil separator 3 is connected to the compressor 1 at one end and to the gas-liquid separator 2 at the other end, and is used to separate the lubricating oil in the gaseous refrigerant;

[0045] A condenser 4 is connected to the compressor 1.

[0046] A four-way valve 5 is provided between the condenser 4 and the compressor 1, and includes four interfaces, which are respectively connected to the compressor 1, the gas-liquid separator 2, and the condenser 4.

[0047] A main liquid pipe 7 is connected to the condenser 4 at one end, and a main gas pipe 6 is connected to the four-way valve 5 at one end.

[0048] Specifically, the refrigerant enters the gas-liquid separator 2 from the main gas pipe 6, is separated into gas and liquid in the gas-liquid separator 2, is compressed into high-temperature and high-pressure gaseous refrigerant in the compressor 1, is cooled into liquid refrigerant in the condenser 4, and flows out of the main liquid pipe 7 to achieve the refrigeration effect.

[0049] Specifically, the oil separator 3 is connected to the exhaust side of the compressor 1, and is used to recover the lubricating oil from the refrigerant vapor discharged from the compressor 1. When the compressor 1 is working, a part of the lubricating oil will be stirred into small oil droplets by the moving parts of the compressor 1, and will be discharged together with the refrigerant vapor. If not separated, the oil droplets will deposit in other parts of the system, such as the condenser 4, affecting the heat exchange efficiency, and may also cause the compressor 1 to be damaged due to lack of oil.

[0050] Specifically, the design of the four-way valve 5 allows the refrigerant to flow in two directions in the system, thereby achieving the summer refrigeration and winter heating functions of the air conditioner.

[0051] Specifically, a plurality of temperature sensing bags are also provided in the outdoor unit, which can monitor the temperatures at different positions in the system, such as the indoor, outdoor, pipeline, condenser 4, etc., and feed back these information to the control system, so as to adjust the refrigerant flow, fan speed, four-way valve 5 position, etc., to achieve the ideal room temperature and energy saving effect.

[0052] In an optional embodiment, the ratio of the diameter of the main gas pipe to the diameter of the main liquid pipe is in the range of 1.6-2.

[0053] In an optional embodiment, when the air conditioner has a capacity of ≤12 tons, the diameter of the main liquid pipe of the outdoor unit is in the range of 11.5-12.5 mm, and the diameter of the main gas pipe is in the range of 18.8-23.8 mm; and / or

[0054] when 12 < air conditioning units ≤ 22, the main liquid pipe of the outdoor unit has a pipe diameter ranging from 15.6 to 16.6 mm, and the main gas pipe has a pipe diameter ranging from 25.5 to 31.5 mm; and / or

[0055] when the air conditioning units > 22, the main liquid pipe of the outdoor unit has a pipe diameter ranging from 20.0 to 22.6 mm, and the main gas pipe has a pipe diameter ranging from 32.6 to 42.9 mm.

[0056] Specifically, the pipe diameters of the main gas pipe 6 and the main liquid pipe 7 are calculated by the refrigerant pipe cross-sectional area, which is calculated by the refrigerant pipe volume flow and the refrigerant flow rate, which is calculated by the refrigerant mass flow and the refrigerant density, which is calculated by the displacement of the compressor 1.

[0057] Specifically, the pipe diameter calculation method of the main gas pipe 6 and the main liquid pipe 7 includes:

[0058] S1, obtain the displacement of the compressor 1, and calculate the refrigerant mass flow m;

[0059] S2, obtain the refrigerant density p, and calculate the refrigerant pipe volume flow V according to the refrigerant mass flow m and the refrigerant density p, which is expressed as V = m / p;

[0060] S3, obtain the refrigerant flow rate s, and calculate the refrigerant pipe cross-sectional area A according to the refrigerant flow rate s and the refrigerant pipe volume flow V, which is expressed as A = V / s;

[0061] wherein the refrigerant flow rate of the main gas pipe 6 is 5 m / s ≤ s ≤ 12 m / s, and the refrigerant flow rate of the main liquid pipe 7 is 18 m / s ≤ s ≤ 32 m / s;

[0062] S4, according to the refrigerant pipe cross-sectional area A, the pipe diameters D of the main gas pipe 6 and the main liquid pipe 7 are calculated, which is expressed as D = 2√A / π.

[0063] For example, taking a 16-unit multi-split air conditioner as an example, the pipe diameters of the main gas pipe 6 and the main liquid pipe 7 are calculated. The 16-unit multi-split air conditioner refers to an air conditioning unit of 16 units, and the air conditioning unit is a unit of air conditioning refrigerating capacity, indicating the electrical energy consumed by the air conditioner per hour.

[0064] The refrigerant mass flow m is calculated as 45 kg / h × 16 = 720 kg / h;

[0065] The return gas temperature is set to 28℃, the low-pressure temperature is 3.5℃, and the low-pressure pressure is 750kpa;

[0066] The refrigerant flow rate of the main gas pipe 6 is 5 m / s ~ 12 m / s, and the refrigerant flow rate of the main liquid pipe 7 is 18 m / s ~ 32 m / s;

[0067] According to the low pressure parameter under the rated working condition, the refrigerant density p = 45 kg / m 3 ;

[0068] The refrigerant volume flow V = m / p = 720 / 45 = 16 m 3 / h = 0.0044 m 3 / s;

[0069] When the refrigerant flow rate of the main gas pipe 6 is 5 m / s, the cross-sectional area A of the refrigerant pipeline of the main gas pipe 6 is 0.0044 / 5 = 0.00088 m 2 ;

[0070] Then the pipe diameter D of the main gas pipe 6 is 2√A / π = 33.7 mm;

[0071] Similarly, when the refrigerant flow rate of the main gas pipe 6 is 12 m / s, the pipe diameter D of the main gas pipe 6 is 21.7 mm;

[0072] Therefore, it can be obtained that the pipe diameter design range of the main gas pipe 6 of the 16P unit is between 21.7 mm and 33.7 mm;

[0073] Similarly, it can be calculated that the pipe diameter design range of the main liquid pipe 7 of the 16P unit is between 13.3 mm and 17.7 mm;

[0074] Similarly, it can be calculated that the pipe diameter range of the main liquid pipe of the outdoor unit when the air conditioner match number is ≤12, 12 < air conditioner match number ≤22 and the air conditioner match number > 22.

[0075] Specifically, by calculation and analysis, the pipe diameters of the main liquid pipe 7 and the main gas pipe 6 are controlled within a reasonable range, avoiding operation problems of the multi-split air conditioner caused by unreasonable pipe diameters, replacing complex simulation and testing with simple theoretical calculation to improve design efficiency, and effectively balancing the pressure loss, oil return and noise of the multi-split air conditioner system on the basis of ensuring the performance and reliability of the unit.

[0076] Referring to FIGS. 1 and 2, Figure 1 and FIGS. 3 and 4, Figure 2 in the optional embodiment, a one-way valve 8 and a first expansion valve 9 are arranged between the main liquid pipe 7 and the condenser 4, the one-way valve 8 and the first expansion valve 9 are arranged in parallel, the one-way valve 8 has a fluid inlet end and a fluid outlet end, the fluid inlet end faces the condenser 4, and the fluid outlet end faces the main liquid pipe 7.

[0077] Specifically, the one-way valve 8 can control the flow of refrigerant from the condenser 4 to the main liquid pipe 7, ensuring that the refrigerant only flows in one direction, preventing the refrigerant from flowing back to the compressor 1 after the compressor 1 is turned off, avoiding damage to the compressor 1 due to the presence of liquid refrigerant during the next start-up, and improving the energy efficiency and stability of the multi-split system.

[0078] Specifically, a liquid storage tank 20 is provided between the one-way valve 8 and the main liquid pipe 7, which is used to store refrigerant.

[0079] Specifically, a liquid storage tank 20 is provided between the one-way valve 8 and the main liquid pipe 7, which can recover excess refrigerant in the system, ensure that the refrigerant in the system is always in a saturated state, meet the refrigerant requirements of each stage, and ensure the normal operation of the air conditioning system.

[0080] Referring to the accompanying Figure 1 As shown in the optional embodiment, a supercooling and enthalpy injection pipeline is provided between the main liquid pipe 7 and the compressor 1, the supercooling and enthalpy injection pipeline is provided with a second expansion valve 10 and a first solenoid valve 11, the supercooling and enthalpy injection pipeline has a branch pipeline, the branch pipeline is connected to the gas-liquid separator 2, and the branch pipeline is provided with a second solenoid valve 12.

[0081] Specifically, the supercooling and enthalpy injection pipeline can supercool the main circulating loop refrigerant before throttling, improve the refrigerating capacity, improve the low-temperature operation stability, and also preheat the low-pressure and low-temperature refrigerant after pressure reduction by the second expansion valve 10 to achieve a suitable medium pressure, providing the compressor 1 with secondary compression to optimize the performance of the refrigeration system.

[0082] Referring to the accompanying Figure 1 As shown in the optional embodiment, the outdoor unit further comprises an oil return capillary tube 13, one end of the oil return capillary tube 13 is connected to the flow path of the oil separator 3 and the gas-liquid separator 2, and the other end is connected to a maintenance valve 14, the oil return capillary tube 13 is used to store lubricating oil in the gas-liquid separator 2.

[0083] Specifically, the oil return capillary tube 13 can protect the compressor 1 from wear and tear, and also maintain stable operation of the system by adjusting the temperature and balancing the pressure, while protecting the system from damage by controlling the flow and pressure of the refrigerant.

[0084] Specifically, the maintenance valve 14 provides protection for the safe operation of the air conditioning system, and by controlling the opening and closing state of the valve stem, quick maintenance and repair of the air conditioning system can be achieved, avoiding problems such as refrigerant leakage, and ensuring the normal operation and service life of the air conditioning system.

[0085] Referring to the accompanying Figure 1As shown, in the optional embodiment, a high-pressure switch 15 and a first pressure sensor 16 are arranged between the compressor 1 and the four-way valve 5, and the first pressure sensor 16 is used to detect the high-pressure pressure when the gas is discharged.

[0086] Specifically, the high-pressure switch 15 is a safety device for protecting the refrigeration cycle system from high-pressure damage, and is a pressure-sensitive automatic switch, which will act when the pressure in the system exceeds the normal operating range, cutting off the power supply of the compressor 1 or starting other protection mechanisms to prevent the system from being damaged; the first pressure sensor 16 is located on the high-pressure side of the system and detects the pressure of the refrigerant on the high-pressure side to prevent the system pressure from being too high.

[0087] Referring to the accompanying drawings Figure 1 As shown, in the optional embodiment, a second pressure sensor 17 is arranged between the gas-liquid separator 2 and the four-way valve 5, and the second pressure sensor 17 is used to detect the low-pressure pressure when the gas is sucked.

[0088] Specifically, the second pressure sensor 17 is located on the low-pressure side of the system and is used to detect the pressure on the low-pressure side to ensure sufficient refrigerant flow and evaporation effect.

[0089] Referring to the accompanying drawings Figure 1 As shown, in the optional embodiment, an oil return pipeline is arranged between the oil separator 3 and the gas-liquid separator 2, and an oil return valve 18 is arranged on the oil return pipeline.

[0090] Specifically, the oil return valve 18 is arranged between the oil separator 3 and the gas-liquid separator 2, which is to ensure that the compressor 1 can obtain sufficient lubricating oil, avoid the wear of the compressor 1, and improve the oil return efficiency of the multi-split system.

[0091] Specifically, a needle valve 19 is further arranged between the oil return valve 18 and the gas-liquid separator 2, and the needle valve 19 can adjust the position of the needle plug by rotating the handle or the motor, so as to accurately control the gas flow; by adjusting the opening degree of the needle valve 19, the flow of the refrigerant or other fluid can be accurately controlled, thereby affecting the refrigeration or heating efficiency of the air conditioning system.

[0092] The application also provides a multi-split system, which comprises the outdoor unit and the indoor unit according to any one of the above embodiments, the indoor unit is connected between the main liquid pipe 7 and the main gas pipe 6, and the outdoor unit is connected with the indoor unit to form a refrigerant circuit.

[0093] Compared with the prior art, the technical effects achieved by the technical scheme are as follows: the multi-split system of the application comprises the outdoor unit according to any one of the above embodiments, and thus has all the beneficial effects of the outdoor unit according to any one of the technical schemes of the application, which will not be described here.

[0094] The above description is intended to be illustrative and not restrictive. One skilled in the art could, with the disclosures herein, make variations, modifications, substitutions, and alterations to the above described embodiments without departing from the scope of the disclosure. Moreover, the above-described examples (or one or more aspects thereof) can be used in combination with each other and the embodiments can be combined with each other in various combinations or permutations as contemplated.

Claims

1. An outdoor unit characterized by comprising: The application relates to an outdoor unit of an air conditioner. The outdoor unit comprises a compressor (1) for compressing refrigerant into high-temperature and high-pressure gaseous refrigerant; a gas-liquid separator (2) connected with the compressor (1); an oil separator (3) with one end connected with the compressor (1) and the other end connected with the gas-liquid separator (2), the oil separator (3) being used for separating lubricating oil in the gaseous refrigerant; a condenser (4) connected with the compressor (1); a four-way valve (5) arranged between the condenser (4) and the compressor (1), the four-way valve (5) comprising four interfaces, the four-way valve (5) being connected with the compressor (1), the gas-liquid separator (2) and the condenser (4) respectively; a main liquid pipe (7) with one end connected with the condenser (4) and a main gas pipe (6) with one end connected with the four-way valve (5); the ratio of the diameter of the main gas pipe to the diameter of the main liquid pipe ranges from 1.6 to 2; a supercooling spray enthalpy pipeline is arranged between the main liquid pipe (7) and the compressor (1), the supercooling spray enthalpy pipeline is provided with a second expansion valve (10) and a first electromagnetic valve (11), the supercooling spray enthalpy pipeline has a branch pipeline, the branch pipeline is connected with the gas-liquid separator (2), and the branch pipeline is provided with a second electromagnetic valve (12); the outdoor unit further comprises an oil return capillary tube (13), one end of the oil return capillary tube (13) is connected on the flow path between the oil separator (3) and the gas-liquid separator (2), and the other end of the oil return capillary tube (13) is connected with an overhauling valve (14), the oil return capillary tube (13) is used for storing lubricating oil in the gas-liquid separator (2); an oil return pipeline is arranged between the oil separator (3) and the gas-liquid separator (2), the oil return pipeline is provided with an oil return valve (18), and a needle valve (19) is further arranged between the oil return valve (18) and the gas-liquid separator (2). When the air conditioner has a capacity of less than or equal to 12, the diameter of the main liquid pipe of the outdoor unit ranges from 11.5 mm to 12.5 mm, and the diameter of the main gas pipe ranges from 18.8 mm to 23.8 mm; when the air conditioner has a capacity of greater than 12 and less than or equal to 22, the diameter of the main liquid pipe of the outdoor unit ranges from 15.6 mm to 16.6 mm, and the diameter of the main gas pipe ranges from 25.5 mm to 31.5 mm; and when the air conditioner has a capacity of greater than 22, the diameter of the main liquid pipe of the outdoor unit ranges from 20.0 mm to 22.6 mm, and the diameter of the main gas pipe ranges from 32.6 mm to 42.9 mm. A one-way valve (8) and a first expansion valve (9) are arranged between the main liquid pipe (7) and the condenser (4), the one-way valve (8) and the first expansion valve (9) are arranged in parallel, the one-way valve (8) has a fluid inlet end and a fluid outlet end, the fluid inlet end faces the condenser (4), and the fluid outlet end faces the main liquid pipe (7). ​ ​ ​ ​ ​ ​ ​ 2. The outdoor unit according to claim 1, characterized by ​ ​ ​ 3. The outdoor unit according to claim 1, characterized by ​ 4. The outdoor unit according to claim 1, characterized by The compressor (1) is provided with a high-pressure switch (15) and a first pressure sensor (16) between the four-way valve (5), and the first pressure sensor (16) is used for detecting the high-pressure pressure when discharging.

5. The outdoor unit according to claim 1, characterized by The gas-liquid separator (2) is provided with a second pressure sensor (17) between the four-way valve (5), and the second pressure sensor (17) is used for detecting the low-pressure pressure when inhaling.

6. A multi-split system, characterized in that, The outdoor unit and the indoor unit as claimed in any one of claims 1-5 are connected between the main liquid pipe (7) and the main gas pipe (6), and the outdoor unit is connected with the indoor unit to form a refrigerant circuit.

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