Air-conditioning System With Mixed Working Medium

Abstract

The application provides an air-conditioning system with mixed working medium, including: a compressor, and a first heat exchanger, wherein the first heat exchanger is communicated with an exhaust port of the compressor, the first heat exchanger is provided with a first flow channel communicated with a first inlet end and a second flow channel communicated with a first outlet end, and a first gas-liquid separator is further connected between the first flow channel and the second flow channel; and the first gas-liquid separator includes a first inlet, a first liquid outlet and a first gas outlet, the first inlet is communicated with the first flow channel, the first gas outlet is communicated with the second flow channel, and a liquid flowing out of the first liquid outlet is capable of being throttled and heated and then connected to a gas supplement port of the compressor for gas supplement. The application enables more high-boiling point refrigerant working medium entering the first heat exchanger to improve condensation performance, and further increases the amount of low-boiling point refrigerant working medium entering the second heat exchanger to improve evaporation performance, thereby solving the problem of poor gas supplement effect of a gas supplement system with mixed working medium, and improving the performance of the air-conditioning system.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the priority to Chinese Patent Application No. 201811425179.X filed by State Intellectual Property Office of The P.R.C on Nov. 27, 2018, and titled "AIR-CONDITIONING SYSTEM WITH MIXED WORKING MEDIUM", the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

[0002] This application belongs to the field of air conditioner technologies, and more particularly, relates to an air-conditioning system with mixed working medium.

BACKGROUND

[0003] At present, an intermediate gas supplement system is widely used because the system can better meet the requirements of low-temperature working conditions and performances thereof can be greatly improved. However, for a mixed working medium composed of two or more refrigerants with different boiling points, under a phase equilibrium state in a gas-liquid separator, low-boiling point components evaporate first, so that the refrigerant supplemented to the compressor is a refrigerant rich in the low-boiling point components. The refrigerant with low boiling point has the characteristics of being easy to evaporate but difficult to condense. However, this gas supplement refrigerant only participates in condensation but not evaporation. This brings two effects: the condensation process contains more low-boiling point components which are not easy to condense, while the evaporation process contains more high-boiling point components which are not easy to evaporate, thus further leading to poor performances of the evaporation process and the condensation process. In fact, for the gas supplement system with mixed working medium, the refrigerant rich in the high-boiling point components is the best one, but this kind of refrigerant belongs to the part which is not easy to evaporate in the gas-liquid separator, and makes the refrigerant difficult to evaporate.

[0004] Because more low-boiling point working medium is typically supplemented into the compressor of the gas supplement system with mixed working medium in the prior art to cause poor performance in the condensation process, and less low-boiling point working medium enters the evaporator to cause poor performance in the evaporation process, thus resulting in technical problems such as poor performances of the gas supplement system, an air-conditioning system with mixed working medium is researched and designed in this application.

SUMMARY

[0005] A technical problem to be solved by this application is to provide an air-conditioning system with mixed working medium so as to overcome the defects in the prior art that more low-boiling point working medium is typically supplemented into the compressor of the gas supplement system with mixed working medium, so that less high-boiling point working medium enters the condenser in a circulation loop, resulting in poor condensation performances.

[0006] This application provides an air-conditioning system with mixed working medium, which includes: a compressor; and a first heat exchanger, wherein the first heat exchanger is communicated with an exhaust port of the compressor, the first heat exchanger is provided with a first inlet end and a first outlet end, and an interior of the first heat exchanger is provided with flow channels capable of allowing the mixed working medium to flow, including a first flow channel communicated with the first inlet end and a second flow channel communicated with the first outlet end, and a first gas-liquid separator is further connected between the first flow channel and the second flow channel; and

[0007] the first gas-liquid separator includes a first inlet, a first liquid outlet and a first gas outlet, the first inlet is communicated with the first flow channel, the first gas outlet is communicated with the second flow channel, and a liquid flowing out of the first liquid outlet is capable of being throttled and heated and then connected to a gas supplement port of the compressor for gas supplement.

[0008] Preferably,

[0009] the first liquid output is further connected with a first branch, and the first branch is provided with a first throttling device, and the exhaust port of the compressor and the first inlet end of the first heat exchanger are connected through a first pipeline.

[0010] Preferably,

[0011] a second gas-liquid separator is further included, wherein the second gas-liquid separator includes a second inlet, a second liquid output and a second gas outlet, and the second inlet is connected with the first branch, so that a fluid throttled by the first throttling device enters the second gas-liquid separator, and the second gas outlet is connected with the gas supplement port of the compressor.

[0012] Preferably,

[0013] the first outlet end of the first heat exchanger is connected with a second pipeline, and a partial section of the second pipeline penetrates into the second gas-liquid separator so as to heat the fluid in the second gas-liquid separator.

[0014] Preferably,

[0015] a second gas-liquid separator is further included, wherein a second throttling device is further arranged on the second pipeline in a downstream section of the second gas-liquid separator along a fluid flow direction, and the second pipeline passing through the second throttling device is capable of being connected to a second inlet end of the second heat exchanger.

[0016] Preferably,

[0017] a second branch is further included, wherein the second branch is communicated with the second liquid outlet of the second gas-liquid separator, and the second branch is further provided with a third throttling device, and the second branch after passing through the third throttling device is capable of being connected to the second inlet end of the second heat exchanger.

[0018] Preferably,

[0019] one second heat exchanger is provided, and the second pipeline is communicated with the second branch and then connected to the first inlet end of the second heat exchanger, and a second outlet end of the second heat exchanger is connected to a gas inlet of the compressor.

[0020] Preferably,

[0021] the second heat exchanger includes a second heat exchanger A and a second heat exchanger B, and the second heat exchanger A and the second heat exchanger B are arranged side by side, the second heat exchanger A is located at an upstream side of the second heat exchanger B in an air flow direction, and the second branch is connected to a second inlet end A of the second heat exchanger A, the second pipeline is connected to a second inlet end B of the second heat exchanger B, and a second outlet end A of the second heat exchanger A is connected with a second outlet end B of the second heat exchanger B and then connected to a gas inlet of the compressor.

[0022] Preferably,

[0023] the second heat exchanger includes a second heat exchanger A and a second heat exchanger B, wherein the second pipeline is connected to a second inlet end B of the second heat exchanger B, a second outlet end B of the second heat exchanger B is communicated with the second branch and then connected with a second inlet end A of the second heat exchanger A, and a second outlet end A of the second heat exchanger A is connected with a gas inlet of the compressor.

[0024] Preferably,

[0025] a third heat exchanger is further included, wherein the third heat exchanger includes a third inlet and a third outlet, the third inlet is connected with the first branch, so that the fluid throttled by the first throttling device enters the third heat exchanger, and the third outlet is connected with the gas supplement port of the compressor.

[0026] Preferably,

[0027] the outlet end of the first heat exchanger is connected with a second pipeline, and a partial section of the second pipeline penetrates into the third heat exchanger so as to heat the fluid in the third heat exchanger.

[0028] Preferably,

[0029] a second heat exchanger is further included, wherein a second throttling device is further arranged on the second pipeline in a downstream section of the third heat exchanger along a fluid flow direction, and the second pipeline passing through the second throttling device is capable of being connected to a second inlet end of the second heat exchanger, and a second outlet end of the second heat exchanger is connected to a gas inlet of the compressor.

[0030] Preferably,

[0031] the first flow channel and the second flow channel in the first heat exchanger are in single-row structures; or, the first flow channel and the second flow channel in the first heat exchanger are both in structures of more than two rows, a liquid gathering pipe is further arranged between more than two rows of the first flow channels and the first gas-liquid separator, and a gas distributing pipe is further arranged between more than two rows of the second flow channels and the first gas-liquid separator.

[0032] A position of the first flow channel on the first heat exchanger connected with the liquid gathering pipe is set within a range of 0.1 to 0.9 of a length ratio of a whole flow channel formed by the first flow channel and the second flow channel.

[0033] Preferably,

[0034] the first heat exchanger is further provided with a first fan; when the second heat exchanger is further included, the second heat exchanger is further provided with a second fan.

[0035] The air-conditioning system with mixed working medium provided by this application has the beneficial effects as follows:

[0036] According to this application, the first gas-liquid separator is connected and arranged in a middle part of the flow channel (i.e., between the first flow channel and the second flow channel) of the first heat exchanger (condenser), and the liquid flowing out of the liquid outlet of the first gas-liquid separator after being throttled and heated is led to the gas supplement port of the compressor, so that refrigerant working medium rich in high-boiling point components can be separated from the liquid outlet of the first gas-liquid separator, thereby effectively overcoming the situation in the prior art that the vast majority of low-boiling point refrigerant working medium is generated by a flash or an intermediate heat exchanger and replenished into the compressor, so as to effectively improve the condensation performances, and meanwhile, effectively improve the amount of the low-boiling point refrigerant working medium entering the evaporator (second heat exchanger), improve the evaporation performances, solve the problem of poor gas supplement effect of the gas supplement system with mixed working medium, and greatly improve the performances of the gas supplement air-conditioning system with mixed working medium.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1 is a schematic diagram showing a system structure of Embodiment 1 of an air-conditioning system with mixed working medium according to this application;

[0038] FIG. 2 is a schematic diagram showing an operating principle of Embodiment 1 of the air-conditioning system with mixed working medium according to this application;

[0039] FIG. 3 is a schematic diagram showing a system structure of Embodiment 2 of the air-conditioning system with mixed working medium according to this application;

[0040] FIG. 4 is a schematic diagram showing an operating principle of Embodiment 2 of the air-conditioning system with mixed working medium according to this application;

[0041] FIG. 5 is a schematic diagram showing a system structure of Embodiment 3 of the air-conditioning system with mixed working medium according to this application;

[0042] FIG. 6 is a schematic diagram showing an operating principle of Embodiment 3 of the air-conditioning system with mixed working medium according to this application;

[0043] FIG. 7 is a schematic diagram showing pipe connecting when a first heat exchanger in the air-conditioning system with mixed working medium is a single-row single-channel fin heat exchanger according to this application;

[0044] FIG. 8 is a schematic diagram showing pipe connecting when the first heat exchanger in the air-conditioning system with mixed working medium is a double-row double-channel fin heat exchanger according to this application; and

[0045] FIG. 9 is a schematic diagram showing pipe connecting when the first heat exchanger in the air-conditioning system with mixed working medium is a three-row three-channel fin heat exchanger according to this application.

[0046] Reference numbers in the drawings are represented as follows:

[0047] 1 refers to compressor; 11 refers to exhaust port; 12 refers to gas supplement port; 13 refers to gas inlet; 2 refers to first heat exchanger; 21 refers to first inlet end; 22 refers to first outlet end; 23 refers to first flow channel; 24 refers to second flow channel; 3 refers to first gas-liquid separator; 31 refers to first inlet; 32 refers to first liquid output; 33 refers to first gas outlet; 4 refers to first throttling device; 5 refers to second throttling device; 6 refers to third throttling device; 7 refers to second gas-liquid separator; 71 refers to second inlet; 72 refers to second liquid output; 73 refers to second gas outlet; 8 refers to second heat exchanger; 81 refers to second inlet end; 82 refers to second outlet end; 8A refers to second heat exchanger A; 8A1 refers to second inlet end A; 8A2 refers to second outlet end A; 8B refers to second heat exchanger B; 8B1 refers to second inlet end B; 8B2 refers to second outlet end B; 9 refers to third heat exchanger; 91 refers to third inlet; 92 refers to third outlet; 100 refers to first branch; 200 refers to first pipeline; 300 refers to second pipeline; 300a refers to partial section; and 400 refers to second branch.

DETAILED DESCRIPTION

[0048] As shown in FIGS. 1 to 9, this application provides an air-conditioning system with mixed working medium, including:

[0049] a compressor 1; and a first heat exchanger 2, wherein the first heat exchanger 2 is communicated with an exhaust port 11 of the compressor 1, the first heat exchanger 2 is provided with a first inlet end 21 and a first outlet end 22, and an interior of the first heat exchanger is provided with flow channels capable of allowing the mixed working medium to flow, including a first flow channel 23 communicated with the first inlet end 21 and a second flow channel 24 communicated with the first outlet end 22, and a first gas-liquid separator 3 is further connected and arranged between the first flow channel 23 and the second flow channel 24; and the first gas-liquid separator 3 includes a first inlet 31, a first liquid outlet 32 and a first gas outlet 33, the first inlet 31 is communicated with the first flow channel 23, the first gas outlet 33 is communicated with the second flow channel 24, and a liquid flowing out of the first liquid outlet 32 is capable of being throttled and heated and then connected to a gas supplement port 12 of the compressor 1 for gas supplement.

[0050] According to this application, the first gas-liquid separator 3 is connected and arranged in a middle part of the flow channel (i.e., between the first flow channel and the second flow channel) of the first heat exchanger 2 (condenser), and the liquid flowing out of the first liquid output 32 of the first gas-liquid separator 3 after being throttled and heated is led to the gas supplement port of the compressor, so that refrigerant working medium rich in high-boiling point components can be separated from the first liquid output 32 of the first gas-liquid separator 3, thereby effectively overcoming the situation in the prior art that the vast majority of low-boiling point refrigerant working medium is generated by a flash or an intermediate heat exchanger and replenished into the compressor, such that more high-boiling point refrigerant working medium enters the condenser in a circulation loop, thus effectively improving the condensation performances, and meanwhile, effectively improving the amount of the low-boiling point refrigerant working medium entering the evaporator (second heat exchanger), improving the evaporation performances, solving the problem of poor gas supplement effect caused by that all the refrigerants supplemented into the gas supplement system with mixed working medium are each low-boiling point refrigerants, and greatly improving the performances of the gas supplement air-conditioning system with mixed working medium.

[0051] Preferably,

[0052] the first liquid output 32 is further connected with a first branch 100, and the first branch 100 is provided with a first throttling device 4. The exhaust port 11 of the compressor 1 and the first inlet end 21 of the first heat exchanger 2 are connected through a first pipeline 200. By connecting the first branch 100 to the first liquid outlet 32 and setting the first throttling device 4 on the first branch 100, a liquid working medium (high-boiling point working medium) collected by the refrigerant working medium separated from the first heat exchanger 2 (condenser) can be throttled and depressurized to provide conditions for the liquid working medium to enter the gas supplement port 12 of the compressor. The exhaust port 11 of the compressor is connected to the first inlet end 21 of the first heat exchanger 2 through the first pipeline 200, so that the high-pressure high-temperature gas compressed by the compressor can enter the first heat exchanger 2 for condensation and heat releasing.

[0053] Preferably,

[0054] referring to FIGS. 1 to 4, a second gas-liquid separator 7 is further included, wherein the second gas-liquid separator 7 includes a second inlet 71, a second liquid output 72 and a second gas outlet 73. The second inlet 71 is connected with the first branch 100, so that a fluid throttled by the first throttling device 4 enters the second gas-liquid separator 7. The second gas outlet 73 is connected with the gas supplement port 12 of the compressor 1. This is a preferred structural form of the implementations of Embodiment 1 and Embodiment 2 of this application, that is, by arranging the second gas-liquid separator 7, on one hand, a liquid refrigerant (high-boiling point refrigerant) can be received from the first liquid outlet 32 of the first gas-liquid separator 3, liquid evaporation can be carried out in the second gas-liquid separator 7, and the evaporated high-boiling point refrigerant can be introduced into the gas supplement port 12 of the compressor, thus realizing the gas supplement function of the high-boiling point working medium, improving condensation performances and increasing the amount of the low-boiling point working medium entering the evaporator.

[0055] Preferably,

[0056] the first outlet end 22 of the first heat exchanger 2 is connected with a second pipeline 300, and a partial section 300a of the second pipeline 300 penetrates into the second gas-liquid separator 7 so as to heat the fluid in the second gas-liquid separator 7. This is a further preferred structural form of Embodiment 1 and Embodiment 2 of this application, that is, the refrigerant condensed by the first heat exchanger 2 is used to heat the high-boiling point refrigerant working medium in the first branch 100 in the second gas-liquid separator 7, so that the high-boiling point refrigerant working medium absorbs heat and evaporates into gas, and is then supplied to the gas supplement port 12 of the compressor to realize the gas supplement of the high-boiling point gas working medium.

[0057] Preferably,

[0058] a second gas-liquid separator 8 is further included, wherein a second throttling device 5 is further arranged on the second pipeline 300 in a downstream section of the second gas-liquid separator 7 along a fluid flow direction, and the second pipeline 300 passing through the second throttling device 5 is capable of being connected to a second inlet end 81 of the second heat exchanger 8. This is a further preferred structural form of Embodiments 1 and 2 of this application. The second heat exchanger can perform evaporation and heat absorption on the refrigerant working medium in a main circulation loop of the air-conditioning system to realize refrigeration and cooling of the outside air, and the second throttling device can throttle and depressurize the refrigerant working medium in the second pipeline to provide conditions for the refrigerant working medium to enter the second heat exchanger for evaporation and heat absorption.

[0059] Preferably,

[0060] a second branch 400 is further included, wherein the second branch 400 is communicated with the second liquid outlet 72 of the second gas-liquid separator 7, and the second branch 400 is further provided with a third throttling device 6, and the second branch 400 after passing through the third throttling device 6 is capable of being connected to the second inlet end 81 of the second heat exchanger 8. This is a further preferred structural form of Embodiments 1 and 2 of this application. The liquid refrigerant separated from the second gas-liquid separator 7 can be recycled through the second branch 400, and further throttled and depressurized to a pressure similar to that of the second heat exchanger 8 (evaporator), and then enter the second heat exchanger 8 for evaporation and heat absorption.

[0061] Preferably,

[0062] According to Embodiment 1, referring to FIGS. 1 to 2, one second heat exchanger 8 is provided. The second pipeline 300 is communicated with the second branch 400 and then connected to the second inlet end 81 of the second heat exchanger 8, and a second outlet end 82 of the second heat exchanger 8 is connected to a gas inlet 13 of the compressor 1. This is a preferred structural form of Embodiment 1 of this application, that is, only one second heat exchanger 8 is used as the evaporator, so that the refrigerant working medium in the second pipeline 300 and the refrigerant working medium in the second branch 400 are mixed first, and then enter the second heat exchanger 8 for heat exchange, thus realizing the mixing function of the low-pressure low-temperature refrigerant and realizing the functions of evaporation and heat absorption.

[0063] FIG. 1 illustrates an air-conditioning system of an intermediate gas supplement system with mixed working medium, including the compressor 1, the first heat exchanger 2, the second heat exchanger 8, the first throttling device 4, the second throttling device 5, the third throttling device 6, the first gas-liquid separator 3 and the second gas-liquid separator 7. The first gas-liquid separator 3 is arranged near the first heat exchanger 2. A liquid gathering pipe and a gas separating pipe are arranged at proper positions of the first heat exchanger 2 (wherein the proper positions here are determined by the dryness of the refrigerant below, for example, when the refrigerant is condensed to a dryness of a proper range (0.15 to 0.85, and an optimized dryness is 0.5 to 0.7), a high-pressure two-phase refrigerant flows into the first gas-liquid separator 3 through the liquid gathering pipe). One end of the liquid gathering pipe is connected with the first flow channel of the first heat exchanger 2. The connected flow channels are each connected with an inlet pipe of the first heat exchanger 2. The other end of the liquid gathering pipe is connected with the gas-liquid separator 3. One end of the gas distributing pipe is connected with the gas-liquid separator 3 and the other end of the gas distributing pipe is connected with the second flow channel of the first heat exchanger 2. The flow channels connected with the gas distributing pipe are each connected with an outlet of the first heat exchanger. A heating coil is arranged in the second gas-liquid separator 7.

[0064] A pipeline connection method of the whole system is as follows: the compressor 1 is connected with all flow channels at an inlet of the first heat exchanger 2, all the flow channels at the inlet of the first heat exchanger 2 are connected with the liquid gathering pipe, the other end of the liquid gathering pipe is connected with an inlet of the first gas-liquid separator 3, a first outlet of the first gas-liquid separator 3 is connected with the gas distributing pipe, the other end of the gas distributing pipe is connected with all the flow channels of the first heat exchanger 2, the flow channels connected with the gas distributing pipe are each connected with an outlet pipeline of the first heat exchanger 2, the outlet pipeline of the first heat exchanger 2 is connected with an inlet of the heating coil of the second gas-liquid separator 7, and an outlet of the second gas-liquid separator 7 is connected with the second throttling device 5; the first liquid output 32 of the first gas-liquid separator 3 is connected with the first throttling device 4, and an outlet of the first throttling device 4 is connected with an inlet of the second gas-liquid separator 7; a first outlet of the second gas-liquid separator 7 is connected with the gas supplement port 12 of the compressor, the second liquid output 72 of the second gas-liquid separator 7 is connected with the third throttling device 6, an outlet of the second throttling device 5 and an outlet of the third throttling device 6 are each connected with the second inlet end 81 of the second heat exchanger 8, and the second outlet end 82 of the second heat exchanger 8 is connected with the gas inlet 13 of the compressor.

[0065] FIG. 2 is a diagram showing an operating principle of the intermediate gas supplement system with mixed working medium disclosed by this application. The high-temperature high-pressure refrigerant discharged from the compressor 1 enters the first heat exchanger 2 and is condensed. When the refrigerant is condensed to a dryness in a suitable range (a certain dryness of 0.15 to 0.85), the high-pressure two-phase refrigerant flows into the first gas-liquid separator 3 through the liquid gathering pipe. In the first gas-liquid separator 3, the refrigerant is divided into two paths, wherein gaseous refrigerant enters the first heat exchanger 2 through the gas distributing pipe and is condensed into supercooled liquid, which flows out from the outlet of the first heat exchanger 2, while liquid refrigerant enters the second gas-liquid separator 7 through the first throttling device 4. The refrigerant flowing out from the outlet of the first throttling device 4 is heated by the refrigerant flowing out from the outlet of the first heat exchanger 2, the evaporated refrigerant enters the compressor 1 through the second gas outlet 73 of the second gas-liquid separator 7, and the non-evaporated liquid refrigerant enters the third throttling device 6 through the second liquid outlet 72 of the second gas-liquid separator 7 to become a low-temperature two-phase refrigerant. The refrigerant flowing out of the first heat exchanger 2 and further supercooled in the second gas-liquid separator 7 enters the second throttling device 5. The low-temperature two-phase refrigerant flowing out of the second throttling device 5 and the third throttling device 6 enters the second heat exchanger 8, evaporates in the second heat exchanger 8 and is sucked by the compressor.

[0066] Preferably,

[0067] according to Embodiment 2, referring to FIGS. 3 to 4, the second heat exchanger 8 includes a second heat exchanger A8A and a second heat exchanger B8B, and the second heat exchanger A8A and the second heat exchanger B8B are arranged side by side, the second heat exchanger A8A is located at an upstream side of the second heat exchanger B8B in an air flow direction, and the second branch 400 is connected to a second inlet end A8A1 of the second heat exchanger A8A, the second pipeline 300 is connected to a second inlet end B8B1 of the second heat exchanger B8B, and a second outlet end A8A2 of the second heat exchanger A8A is connected with a second outlet end B8B2 of the second heat exchanger B8B and then connected to a gas inlet of the compressor 1. This is a preferred structural form of Embodiment 2 of this application, that is, only two second heat exchangers A and B arranged side by side are used as THE evaporators, so that the refrigerant working medium in the second pipeline 300 and the refrigerant working medium in the second branch 400 respectively enter different heat exchangers for heat exchange, and then mix and return to the compressor after heat exchange to realize the evaporation and heat absorption of the low-pressure low-temperature refrigerant. Because the temperature of the refrigerant working medium in the second branch 400 is higher, hot air first passes through the second heat exchanger A for heat exchange and cooling first, and then passes through the second heat exchanger B for cooling, thus realizing gradual cooling from high temperature to low temperature and improving the heat exchange efficiency.

[0068] FIG. 3 shows an air-conditioning system of a dual-temperature gas supplement system with mixed working medium disclosed by this application. The system includes the compressor 1, the first heat exchanger 2, the second heat exchanger A8A, the second heat exchanger B8B, the first throttling device 4, the second throttling device 5, the third throttling device 6, the first gas-liquid separator 3 and the second gas-liquid separator 7; wherein, the first gas-liquid separator 3 is arranged near the first heat exchanger 2. A liquid gathering pipe and a gas separating pipe are arranged at proper positions of the first heat exchanger 2 (ditto). One end of the liquid gathering pipe is connected with all the flow channels of the first heat exchanger 2. The connected flow channels are each connected with the first heat exchanger 2. The other end of the liquid gathering pipe is connected with the gas-liquid separator 3. One end of the gas distributing pipe is connected with the gas-liquid separator 3 and the other end of the gas distributing pipe is connected with all the flow channels of the first heat exchanger 2. The flow channels connected with the gas distributing pipe are each connected with an outlet of the first heat exchanger 2. A heating coil is arranged in the second gas-liquid separator 7.

[0069] A pipeline connection method of the whole system is as follows: the compressor 1 is connected with all flow channels at an inlet of the first heat exchanger 2, all the flow channels at the inlet of the first heat exchanger 2 are connected with the liquid gathering pipe, the other end of the liquid gathering pipe is connected with an inlet of the first gas-liquid separator 3, a first outlet of the first gas-liquid separator 3 is connected with the gas distributing pipe, the other end of the gas distributing pipe is connected with all the flow channels of the first heat exchanger 2, the flow channels connected with the gas distributing pipe are each connected with an outlet pipeline of the first heat exchanger 2, the first gas outlet 33 of the first heat exchanger 2 is connected with an inlet of the heating coil of the second gas-liquid separator 7, an outlet of the heating coil is connected with the second throttling device 5, an outlet of the second throttling device 5 is connected with an inlet of a low-temperature flow channel of the second heat exchanger B8B, and an outlet of the low-temperature flow channel is connected with the gas inlet 13 of the compressor; the first liquid output 32 of the first gas-liquid separator 3 is connected with the first throttling device 4, and an outlet of the first throttling device 4 is connected with the second inlet 71 of the second gas-liquid separator 7; the second gas outlet 73 of the second gas-liquid separator 7 is connected with the gas supplement port 12 of the compressor, the second liquid outlet 72 of the second gas-liquid separator 7 is connected with the third throttling device 6, an outlet of the third throttling device 6 is connected with an inlet of a high-temperature flow channel of the second heat exchanger A8A, and an outlet of the high-temperature flow channel of the second heat exchanger A8A is connected with the gas inlet 13 of the compressor.

[0070] FIG. 4 is a diagram showing an operating principle of the intermediate gas supplement system with mixed working medium disclosed by this application. The high-temperature high-pressure refrigerant discharged from the compressor enters the first heat exchanger 2 and is condensed. When the refrigerant is condensed to a dryness in a suitable range (a certain dryness of 0.15 to 0.85, and an optimized dryness of 0.5 to 0.7), the high-pressure two-phase refrigerant flows into the first gas-liquid separator 3b the liquid gathering pipe. In the first gas-liquid separator 3, the refrigerant is divided into two paths, wherein gaseous refrigerant enters the first heat exchanger 2 through the gas distributing pipe and is condensed into supercooled liquid, which flows out from the outlet of the first heat exchanger 2, while liquid refrigerant enters the second gas-liquid separator 7 through the first throttling device 4. The refrigerant flowing out from the outlet of the first throttling device 4 is heated by the refrigerant flowing out from the outlet of the first heat exchanger 2, the evaporated refrigerant enters the compressor through the second gas outlet 73 of the second gas-liquid separator 7, and the non-evaporated liquid refrigerant enters the third throttling device 6 through the second liquid outlet 72 of the second gas-liquid separator 7 to become a low-temperature two-phase refrigerant and then enter a high-temperature flow channel of the second heat exchanger 8. The refrigerant flowing out of the first heat exchanger 2 and further supercooled in the second gas-liquid separator 7 enters the second throttling device 5 and becomes a low-temperature two-phase refrigerant and then enters a low-temperature flow channel of the second heat exchanger 8. The refrigerant evaporated in the high-temperature flow channel and the refrigerant evaporated in the low-temperature flow channel are each connected with the gas inlet 13 of the compressor.

[0071] Preferably,

[0072] according to Embodiment 3, referring to FIGS. 5 to 6, a third heat exchanger 9 is further included, wherein the third heat exchanger 9 includes a third inlet 91 and a third outlet 92, the third inlet 91 is connected with the first branch 100, so that the fluid throttled by the first throttling device 4 enters the third heat exchanger 9, and the third outlet 92 is connected with the gas supplement port 12 of the compressor 1. This is a preferred structural form of Embodiment 3 of this application. On the basis of Embodiment 1 and Embodiment 2, the second gas-liquid separator is replaced into the third heat exchanger. On one hand, a liquid refrigerant (high-boiling point refrigerant) can be received from the first liquid outlet end of the first gas-liquid separator, liquid evaporation can be carried out in the third heat exchanger, and the evaporated high-boiling point refrigerant can be introduced into the gas supplement port of the compressor, thus realizing the gas supplement function of the high-boiling point working medium, improving condensation performances and increasing the amount of the low-boiling point working medium entering the evaporator.

[0073] Preferably,

[0074] the first outlet end 22 of the first heat exchanger 2 is connected with a second pipeline 300, and a partial section 300a of the second pipeline 300 penetrates into the third heat exchanger 9 so as to heat the fluid in the third heat exchanger. This is a further preferred structural form of Embodiment 3 of this application, that is, the refrigerant condensed by the first heat exchanger is used to heat the high-boiling point refrigerant in the first branch in the third heat exchanger, so that the high-boiling point refrigerant working medium absorbs heat and evaporates into gas, and is then supplied to the gas supplement port of the compressor to realize the gas supplement of the high-boiling point gas working medium.

[0075] Preferably,

[0076] a second heat exchanger 8 is further included, wherein a second throttling device 5 is further arranged on the second pipeline 300 in a downstream section of the third heat exchanger 9 along a fluid flow direction, and the second pipeline 300 passing through the second throttling device 5 is capable of being connected to a second inlet end 81 of the second heat exchanger 8, and a second outlet end 82 of the second heat exchanger 8 is connected to a gas inlet 13 of the compressor 1. This is a further preferred structural form of Embodiment 3 of this application. The second heat exchanger can perform evaporation and heat absorption on the refrigerant working medium in a main circulation loop of the air-conditioning system to realize refrigeration and cooling of the outside air, and the second throttling device can throttle and depressurize the refrigerant working medium in the second pipeline to provide conditions for the refrigerant working medium to enter the second heat exchanger for evaporation and heat absorption.

[0077] FIG. 5 shows a gas supplement system with an intermediate heat exchanger disclosed by this application. The system includes the compressor 1, the first heat exchanger 2, the second heat exchanger 8, the third heat exchanger 9, the first throttling device 4, the second throttling device 5, and the first gas-liquid separator 3. The first gas-liquid separator 3 is arranged near the first heat exchanger 2. A liquid gathering pipe and a gas separating pipe are arranged at proper positions of the first heat exchanger 2. One end of the liquid gathering pipe is connected with the first flow channel of the first heat exchanger 2. The connected flow channels are each connected with the first inlet end 21 of the first heat exchanger 2. The other end of the liquid gathering pipe is connected with the gas-liquid separator 3. One end of the gas distributing pipe is connected with the gas-liquid separator 3 and the other end of the gas distributing pipe is connected with the second flow channel of the first heat exchanger 2. The flow channels connected with the gas distributing pipe are each connected with an outlet of the first heat exchanger 2.

[0078] A pipeline connection method of the whole system is as follows: the compressor 1 is connected with all flow channels at an inlet of the first heat exchanger 2, all the flow channels at the inlet of the first heat exchanger 2 are connected with the liquid gathering pipe, the other end of the liquid gathering pipe is connected with an inlet of the first gas-liquid separator 3, the first gas outlet 33 of the first gas-liquid separator 3 is connected with the gas distributing pipe, the other end of the gas distributing pipe is connected with all the flow channels of the first heat exchanger 2, the flow channels connected with the gas distributing pipe are each connected with an outlet pipeline of the first heat exchanger 2, the first outlet end 22 of the first heat exchanger 2 after passing through the third heat exchanger 9 is connected to the second inlet end 81 of the second heat exchanger 8 by the second throttling device 5, and the second outlet end 82 of the second heat exchanger 8 is connected with the gas inlet 13 of the compressor. The first liquid output 32 of the first gas-liquid separator 3 is connected with an inlet of the first throttling device 4, an outlet of the first throttling device 4 is connected with the third inlet 91 of the third heat exchanger 9, and the third outlet 92 of the third heat exchanger 9 is connected with the gas supplement port 12 of the compressor 1.

[0079] FIG. 6 is a diagram showing an operating principle of the intermediate gas supplement system with mixed working medium disclosed by this application. The high-temperature high-pressure refrigerant discharged from the compressor enters the first heat exchanger and is condensed. When the refrigerant is condensed to a dryness in a suitable range (an optimized dryness is 0.15 to 0.4), the high-pressure two-phase refrigerant flows into the first gas-liquid separator 3 through the liquid gathering pipe. In the first gas-liquid separator 3, the refrigerant is divided into two paths, wherein gaseous refrigerant enters the first heat exchanger 2 through the gas distributing pipe and is condensed into supercooled liquid, which flows out from the outlet of the first heat exchanger 2 and enters the third heat exchanger 9, while liquid refrigerant enters the third heat exchanger 9 through the first throttling device 4. The refrigerant flowing out from the outlet of the first throttling device 4 absorbs heat and evaporates in the third heat exchanger 9 and then enters the compressor through the gas supplement port 12 of the compressor. The refrigerant flowing out from the outlet of the first heat exchanger 2 is further supercooled in the third heat exchanger 9 and then enters the second throttling device 5. The refrigerant flowing out of the second throttling device 5 is evaporated by the second heat exchanger 8 and then sucked by the compressor.

[0080] Preferably,

[0081] the first flow channel 23 and the second flow channel 24 in the first heat exchanger 2 are in single-row structures;

[0082] or, the first flow channel 23 and the second flow channel 24 in the first heat exchanger 2 are both in structures of more than two rows, a liquid gathering pipe (not shown, the multiple rows of the first flow channels can gather or collect liquids by the liquid gathering pipe, and then are communicated to the first gas-liquid separator) is further arranged between more than two rows of the first flow channel 23 and the first gas-liquid separator 3, and a gas distributing pipe (not shown, the first gas-liquid separator can carry out gas distribution by the gas distribution pipe, and then the separated multiple gas channels can be communicated to multiple rows of the second flow channels) is further arranged between more than two rows of the second flow channel 24 and the first gas-liquid separator 3. This is a preferred connection method between the first flow channel and the second flow channel and the first gas-liquid separator according to this application, that is, the flow channels in single-row structures are directly connected with the first gas-liquid separator; when the flow channels are in structures of more than two rows, liquid is gathered in the multiple rows first, so that the refrigerant working medium is collected and then introduced into the first gas-liquid separator for gas-liquid separation, and then the separated gas is divided into multiple gas flow channels through the gas distributing pipe and introduced into the second flow channel to separate the high-boiling point working medium and return the low-boiling point working medium to the first heat exchanger for heat exchange, thus achieving the beneficial effect of supplementing the high-boiling point working medium into the compressor.

[0083] Preferably,

[0084] the first heat exchanger 2 is further provided with a first fan; when the second heat exchanger 8 is further included, the second heat exchanger 8 is further provided with a second fan. This is a preferred structural form of the first heat exchanger and the second heat exchanger according to this application, which can improve the heat exchange effect and capacity of the first heat exchanger and the second heat exchanger.

[0085] In this application, the liquid gathering pipe refers to the connecting pipe connecting all the flow channels of the first heat exchanger into the gas-liquid separator; the gas distribution pipe refers to the connecting pipe connecting the gas outlet of the gas-liquid separator with each flow channel of the first heat exchanger; and the low-temperature flow channel and the high-temperature flow channel refer to that the flow channel passing through the heat exchanger first is the high-temperature flow channel while the flow channel passing through the heat exchanger later is the low-temperature flow channel from the air flow direction.

[0086] this application preferably provides an air-conditioning system of an intermediate gas supplement system with mixed working medium, including the compressor, the first heat exchanger, the second heat exchanger, the first throttling device, the second throttling device, the third throttling device, the first gas-liquid separator and the second gas-liquid separator; wherein, the first gas-liquid separator is arranged near the first heat exchanger. A liquid gathering pipe and a gas separating pipe are arranged at proper positions of the first heat exchanger. One end of the liquid gathering pipe is connected with all flow channels of the first heat exchanger. The connected flow channels are each connected with an inlet pipe of the first heat exchanger. The other end of the liquid gathering pipe is connected with the gas-liquid separator. One end of the gas distributing pipe is connected with the gas-liquid separator and the other end of the gas distributing pipe is connected with all the flow channels of the first heat exchanger. The flow channels connected with the gas distributing pipe are each connected with an outlet of the first heat exchanger. A heating coil is arranged in the second gas-liquid separator.

[0087] A pipeline connection method of the whole system is as follows: the compressor is connected with all flow channels at an inlet of the first heat exchanger, all the flow channels at the inlet of the first heat exchanger are connected with the liquid gathering pipe, the other end of the liquid gathering pipe is connected with an inlet of the first gas-liquid separator, a first outlet of the first gas-liquid separator is connected with the gas distributing pipe, the other end of the gas distributing pipe is connected with all the flow channels of the first heat exchanger, the flow channels connected with the gas distributing pipe are each connected with an outlet pipeline of the first heat exchanger, the outlet pipeline of the first heat exchanger is connected with an inlet of the heating coil of the second gas-liquid separator, and an outlet of the second gas-liquid separator is connected with the second throttling device; the second outlet of the first gas-liquid separator is connected with the first throttling device, and an outlet of the first throttling device is connected with an inlet of the second gas-liquid separator; the first outlet of the second gas-liquid separator is connected with the gas supplement port of the compressor, a second outlet of the second gas-liquid separator is connected with the third throttling device, an outlet of the second throttling device and an outlet of the third throttling device are each connected with an inlet of the second heat exchanger 8, and an outlet of the second heat exchanger is connected with the gas inlet of the compressor.

[0088] A position of the flow channel on the first heat exchanger connected with the liquid gathering pipe is set within a range of 0.1 to 0.9 of a length ratio of a whole flow channel. The position of the flow channel on the first heat exchanger connected with the liquid gathering pipe may be set according to the dryness of the refrigerant in the pipe. Preferably, when the dryness of the refrigerant in the pipe is in the range of 0.15 to 0.85, the position corresponding to the dryness enables the refrigerant pipe to be connected with the liquid gathering pipe.

[0089] The system may be built as a dual-temperature gas supplement system with mixed working medium.

[0090] The system includes the compressor, the first heat exchanger, the second heat exchanger, the first throttling device, the second throttling device, the third throttling device, the first gas-liquid separator and the second gas-liquid separator; wherein, the first gas-liquid separator is arranged near the first heat exchanger. A liquid gathering pipe and a gas separating pipe are arranged at proper positions of the first heat exchanger. One end of the liquid gathering pipe is connected with all flow channels of the first heat exchanger. The connected flow channels are each connected with an inlet pipe of the first heat exchanger. The other end of the liquid gathering pipe is connected with the gas-liquid separator. One end of the gas distributing pipe is connected with the gas-liquid separator and the other end of the gas distributing pipe is connected with all the flow channels of the first heat exchanger. The flow channels connected with the gas distributing pipe are each connected with an outlet of the first heat exchanger. A heating coil is arranged in the second gas-liquid separator.

[0091] A pipeline connection method of the whole system is as follows: the compressor 1 is connected with all flow channels at an inlet of the first heat exchanger, all the flow channels at the inlet of the first heat exchanger are connected with the liquid gathering pipe, the other end of the liquid gathering pipe is connected with an inlet of the first gas-liquid separator, a first outlet of the first gas-liquid separator is connected with the gas distributing pipe, the other end of the gas distributing pipe is connected with all the flow channels of the first heat exchanger, the flow channels connected with the gas distributing pipe are each connected with an outlet pipeline of the first heat exchanger, the outlet pipeline of the first heat exchanger is connected with an inlet of the heating coil of the second gas-liquid separator, an outlet of the heating coil is connected with the second throttling device 5, an outlet of the second throttling device 5 is connected with an inlet of a low-temperature flow channel of the second heat exchanger 8, and an outlet of the low-temperature flow channel is connected with the gas inlet of the compressor; the second outlet of the first gas-liquid separator is connected with the first throttling device, and an outlet of the first throttling device is connected with an inlet of the second gas-liquid separator; the first outlet of the second gas-liquid separator is connected with the gas supplement port of the compressor, a second outlet of the second gas-liquid separator is connected with the third throttling device 6, an outlet of the third throttling device is connected with an inlet of the high-temperature flow channel of the second heat exchanger 8, and an outlet of the high-temperature flow channel of the second heat exchanger is connected with the gas inlet of the compressor.

[0092] A position of the flow channel on the first heat exchanger connected with the liquid gathering pipe may be set within a range of 0.1 to 0.9 of a length ratio of a whole flow channel, and a preferred ratio is 0.6 to 0.8. The position of the flow channel on the first heat exchanger connected with the liquid gathering pipe may be set according to the dryness of the refrigerant in the pipe. Preferably, when the dryness of the refrigerant in the pipe is in the range of 0.15 to 0.85, the position corresponding to the dryness enables the refrigerant pipe to be connected with the liquid gathering pipe. A further preferred range is 0.3 to 0.5, and the position corresponding to the dryness enables the refrigerant pipe to be connected with the liquid gathering pipe.

[0093] The second heat exchanger may be set as one heat exchanger or two heat exchangers.

[0094] When the second heat exchanger is set as one heat exchanger, the air flow direction and the flow channel of the heat exchanger may be set such that air first flows through the high-temperature flow channel and then flows through the low-temperature flow channel. At this time, the inlet of the high-temperature flow channel is connected with the outlet of the second throttling device 5, and the inlet of the low-temperature flow channel is connected with the outlet of the first throttling device.

[0095] When the second heat exchanger is set as two heat exchangers, air first flows through the high-temperature evaporator and then flows through the low-temperature evaporator, an inlet of the high-temperature evaporator is connected with the outlet of the second throttle device, and an inlet of the low-temperature evaporator is connected with the outlet of the first throttle device.

[0096] The system may be built as a gas supplement system with an intermediate heat exchanger.

[0097] The system includes the compressor, the first heat exchanger, the second heat exchanger, the third heat exchanger, the first throttling device, the second throttling device, and the first gas-liquid separator; wherein, the first gas-liquid separator is arranged near the first heat exchanger. A liquid gathering pipe and a gas separating pipe are arranged at proper positions of the first heat exchanger. One end of the liquid gathering pipe is connected with all flow channels of the first heat exchanger. The connected flow channels are each connected with an inlet pipe of the first heat exchanger. The other end of the liquid gathering pipe is connected with the gas-liquid separator. One end of the gas distributing pipe is connected with the gas-liquid separator and the other end of the gas distributing pipe is connected with all the flow channels of the first heat exchanger. The flow channels connected with the gas distributing pipe are each connected with an outlet of the first heat exchanger.

[0098] A pipeline connection method of the whole system is as follows: the compressor is connected with all flow channels at an inlet of the first heat exchanger, all the flow channels at the inlet of the first heat exchanger are connected with the liquid gathering pipe, the other end of the liquid gathering pipe is connected with an inlet of the first gas-liquid separator, the first outlet of the first gas-liquid separator is connected with the gas distributing pipe, the other end of the gas distributing pipe is connected with all the flow channels of the first heat exchanger, the flow channels connected with the gas distributing pipe are each connected with an outlet pipeline of the first heat exchanger, the outlet pipeline of the first heat exchanger is connected with a first inlet of the third heat exchanger, the first outlet of the third heat exchanger is connected with an inlet of the second throttling device 5, an outlet of the second throttling device 5 is connected with an inlet of the second heat exchanger, and an outlet of the second heat exchanger is connected with the gas inlet of the compressor. The second outlet of the first gas-liquid separator is connected with the inlet of the first throttling device 4, the outlet of the first throttling device 4 is connected with a second inlet of the third heat exchanger, and a second outlet of the third heat exchanger is connected with the gas supplement port of the compressor.

[0099] A position of the flow channel on the first heat exchanger connected with the liquid gathering pipe may be set within a range of 0.1 to 0.9 of a length ratio of a whole flow channel, and a preferred ratio is 0.2 to 0.5. The position of the flow channel on the first heat exchanger connected with the liquid gathering pipe may be set according to the dryness of the refrigerant in the pipe. Preferably, when the dryness of the refrigerant in the pipe is in the range of 0.15 to 0.85, the position corresponding to the dryness enables the refrigerant pipe to be connected with the liquid gathering pipe. A further preferred range is 0.2 to 0.35, and the position corresponding to the dryness enables the refrigerant pipe to be connected with the liquid gathering pipe.

[0100] The throttling device may be set as an electronic expansion valve or a capillary tube.

[0101] The first heat exchanger may be set as a double-pipe heat exchanger.

[0102] The second heat exchanger may be set as a double-pipe heat exchanger. Cold water may pass through the high-temperature evaporator and then passes through the low-temperature evaporator, or two paths of cold water respectively pass through the high-temperature evaporator and the low-temperature evaporator to produce water with two temperatures.

[0103] The compressor may be a two-stage compressor or a quasi-two-stage compressor.

[0104] Those described above are merely preferred embodiments of this application, but are not intended to limit this application. Any modifications, equivalent substitutions and improvements made without departing from the spirit and principle of this application shall all fall in the scope of protection of this application. Those described above are merely preferred implementations of this application. It should be noted that those of ordinary skills in the art may further make a plurality of improvements and decorations without departing from the technical principle of this application, and these improvements and decorations shall also fall within the scope of protection of this application.

Claims

1. An air-conditioning system with mixed working medium, comprising: a compressor (1); and a first heat exchanger (2), wherein the first heat exchanger (2) is communicated with an exhaust port (11) of the compressor (1), the first heat exchanger (2) is provided with a first inlet end (21) and a first outlet end (22), and an interior of the first heat exchanger (2) is provided with flow channels capable of allowing the mixed working medium to flow, comprising a first flow channel (23) communicated with the first inlet end (21) and a second flow channel (24) communicated with the first outlet end (22), and a first gas-liquid separator (3) is arranged between the first flow channel (23) and the second flow channel (24); and the first gas-liquid separator (3) comprises a first inlet (31), a first liquid outlet (32) and a first gas outlet (33), the first inlet (31) is communicated with the first flow channel (23), the first gas outlet (33) is communicated with the second flow channel (24), and a liquid flowing out of the first liquid outlet (32) is capable of being throttled and heated and then connected to a gas supplement port (12) of the compressor (1) for gas supplement.

2. The air-conditioning system according to claim 1, wherein the first liquid output (32) is further connected with a first branch (100), and the first branch (100) is provided with a first throttling device (4), and the exhaust port (11) of the compressor (1) and the first inlet end (21) of the first heat exchanger (2) are connected through a first pipeline (200).

3. The air-conditioning system according to claim 2, further comprising a second gas-liquid separator (7), wherein the second gas-liquid separator (7) comprises a second inlet (71), a second liquid output (72) and a second gas outlet (73), and the second inlet (71) is connected with the first branch (100), so that a fluid throttled by the first throttling device (4) enters the second gas-liquid separator (7), and the second gas outlet (73) is connected with the gas supplement port (12) of the compressor (1).

4. The air-conditioning system according to claim 3, wherein the first outlet end (22) of the first heat exchanger (2) is connected with a second pipeline (300), and a partial section (300a) of the second pipeline (300) penetrates into the second gas-liquid separator (7) so as to heat the fluid in the second gas-liquid separator (7).

5. The air-conditioning system according to claim 4, further comprising a second heat exchanger (8), wherein a second throttling device (5) is further arranged on the second pipeline (300) in a downstream section of the second gas-liquid separator (7) along a fluid flow direction, and the second pipeline (300) passing through the second throttling device (5) is capable of being connected to a second inlet end (81) of the second heat exchanger (8).

6. The air-conditioning system according to claim 5, further comprising a second branch (400), wherein the second branch (400) is communicated with the second liquid outlet (72) of the second gas-liquid separator (7), and the second branch (400) is further provided with a third throttling device (6), and the second branch (400) is communicated with the third throttling device (6) and then connected with the second inlet end (81) of the second heat exchanger (8).

7. The air-conditioning system according to claim 6, wherein one second heat exchanger (8) is provided, and the second pipeline (300) is communicated with the second branch (400) and then connected to the second inlet end (81) of the second heat exchanger (8), and a second outlet end (82) of the second heat exchanger (8) is connected to a gas inlet (13) of the compressor (1).

8. The air-conditioning system according to claim 6, wherein the second heat exchanger (8) comprises a second heat exchanger A(8A) and a second heat exchanger B(8B), and the second heat exchanger A(8A) and the second heat exchanger B(8B) are arranged side by side, the second heat exchanger A(8A) is located at an upstream side of the second heat exchanger B(8B) in an air flow direction, and the second branch (400) is connected to a second inlet end A(8A1) of the second heat exchanger A(8A), the second pipeline (300) is connected to a second inlet end B(8B1) of the second heat exchanger B(8B), and a second outlet end A(8A2) of the second heat exchanger A(8A) is connected with a second outlet end B(8B2) of the second heat exchanger B(8B) and then connected to a gas inlet (13) of the compressor (1).

9. The air-conditioning system according to claim 6, wherein the second heat exchanger (8) comprises a second heat exchanger A(8A) and a second heat exchanger B(8B), wherein the second pipeline (300) is connected to a second inlet end B(8B1) of the second heat exchanger B(8B), a second outlet end B(8B2) of the second heat exchanger B(8B) is communicated with the second branch (400) and then connected with a second inlet end A(8A1) of the second heat exchanger A(8A), and a second outlet end A(8A2) of the second heat exchanger A(8A) is connected with a gas inlet (13) of the compressor (1).

10. The air-conditioning system according to claim 2, further comprising a third heat exchanger (9), wherein the third heat exchanger (9) comprises a third inlet (91) and a third outlet (92), the third inlet (91) is connected with the first branch (100), so that the fluid throttled by the first throttling device (4) enters the third heat exchanger (9), and the third outlet (92) is connected with the gas supplement port (12) of the compressor (1).

11. The air-conditioning system according to claim 10, wherein the first outlet end (22) of the first heat exchanger (2) is connected with a second pipeline (300), and a partial section (300a) of the second pipeline (300) penetrates into the third heat exchanger (9) so as to heat the fluid in the third heat exchanger (9).

12. The air-conditioning system according to claim 11, further comprising a second heat exchanger (8), wherein a second throttling device (5) is further arranged on the second pipeline (300) in a downstream section of the third heat exchanger (9) along a fluid flow direction, and the second pipeline (300) passing through the second throttling device (5) is capable of being connected to a second inlet end (81) of the second heat exchanger (8), and a second outlet end (82) of the second heat exchanger (8) is connected to a gas inlet (13) of the compressor (1).

13. The air-conditioning system according to claim 12, wherein the first flow channel (23) and the second flow channel (24) in the first heat exchanger (2) are in single-row structures; or, the first flow channel (23) and the second flow channel (24) in the first heat exchanger (2) are both in structures of more than two rows, a liquid gathering pipe is further arranged between more than two rows of the first flow channels (23) and the first gas-liquid separator (3), and a gas distributing pipe is further arranged between more than two rows of the second flow channels (24) and the first gas-liquid separator (3).

14. The air-conditioning system according to claim 13, wherein a position of the first flow channel (23) on the first heat exchanger (2) connected with the liquid gathering pipe is set within a range of 0.1 to 0.9 of a length ratio of a whole flow channel formed by the first flow channel (23) and the second flow channel (24).

15. The air-conditioning system according to claim 14, wherein the first heat exchanger (2) is further provided with a first fan; when the second heat exchanger (8) is further comprised, the second heat exchanger (8) is further provided with a second fan.

16. An air-conditioning system with mixed working medium, comprising: a compressor (1); and a first heat exchanger (2), wherein the first heat exchanger (2) is communicated with an exhaust port (11) of the compressor (1), the first heat exchanger (2) is provided with a first inlet end (21) and a first outlet end (22), and an interior of the first heat exchanger (2) is provided with flow channels capable of allowing the mixed working medium to flow, comprising a first flow channel (23) communicated with the first inlet end (21) and a second flow channel (24) communicated with the first outlet end (22), and a first gas-liquid separator (3) is arranged between the first flow channel (23) and the second flow channel (24); and the first gas-liquid separator (3) comprises a first inlet (31), a first liquid outlet (32) and a first gas outlet (33), the first inlet (31) is communicated with the first flow channel (23), the first gas outlet (33) is communicated with the second flow channel (24), and a liquid flowing out of the first liquid outlet (32) is capable of being throttled and heated and then connected to a gas supplement port (12) of the compressor (1) for gas supplement; and wherein the first flow channel (23) and the second flow channel (24) in the first heat exchanger (2) are in single-row structures; or, the first flow channel (23) and the second flow channel (24) in the first heat exchanger (2) are both in structures of more than two rows, a liquid gathering pipe is further arranged between more than two rows of the first flow channels (23) and the first gas-liquid separator (3), and a gas distributing pipe is further arranged between more than two rows of the second flow channels (24) and the first gas-liquid separator (3).

17. An air-conditioning system with mixed working medium, comprising: a compressor (1); and a first heat exchanger (2), wherein the first heat exchanger (2) is communicated with an exhaust port (11) of the compressor (1), the first heat exchanger (2) is provided with a first inlet end (21) and a first outlet end (22), and an interior of the first heat exchanger (2) is provided with flow channels capable of allowing the mixed working medium to flow, comprising a first flow channel (23) communicated with the first inlet end (21) and a second flow channel (24) communicated with the first outlet end (22), and a first gas-liquid separator (3) is arranged between the first flow channel (23) and the second flow channel (24); and the first gas-liquid separator (3) comprises a first inlet (31), a first liquid outlet (32) and a first gas outlet (33), the first inlet (31) is communicated with the first flow channel (23), the first gas outlet (33) is communicated with the second flow channel (24), and a liquid flowing out of the first liquid outlet (32) is capable of being throttled and heated and then connected to a gas supplement port (12) of the compressor (1) for gas supplement; and wherein the first heat exchanger (2) is further provided with a first fan; when the second heat exchanger (8) is further comprised, the second heat exchanger (8) is further provided with a second fan.