A multi-connected air conditioner

Abstract

The present invention provides a multi-split air conditioner, comprising: an outdoor unit; a plurality of transfer units connected to the outdoor unit through an air pipe and a liquid pipe; a plurality of indoor units; a plurality of indoor units connected to the plurality of transfer units in a one-to-one correspondence; and a waste heat recovery pipe arranged between the plurality of transfer units for recovering waste heat between the transfer units. The present invention can solve the technical problems of limited distance between the transfer unit and the indoor unit, heat waste and low efficiency when the multi-split air conditioner is running.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a multi-split air conditioner. Background Art

[0002] At present, multi-split air conditioners are widely used. By connecting two or more indoor units with one outdoor unit through piping, the purpose of controlling multiple units with one unit can be achieved. In this process, the needs of simultaneous cooling, heating, and cooling and heating of multiple indoor units can be met.

[0003] At present, although there are multi-split air conditioners that can perform cooling and heating at the same time, it is necessary to add a transfer unit between the outdoor unit and the indoor unit to achieve the purpose of simultaneous cooling and heating of multiple indoor units. However, the transfer unit set up is a centralized transfer unit, that is, one transfer unit is connected to multiple indoor units. If there are more indoor units connected to the transfer unit, the distance between the indoor unit and the transfer unit will increase. When it exceeds a certain distance, it will affect the cooling or heating efficiency of the indoor unit; even if a one-to-one connection method between the transfer unit and the indoor unit is adopted, there are disadvantages of heat loss and low efficiency. Summary of the invention

[0004] The present invention can solve the technical problems of limited distance between the transfer unit and the indoor unit, heat waste and low efficiency during the operation of the multi-split air conditioner.

[0005] In order to solve the above problems, the present invention provides a multi-split air conditioner, which includes: an outdoor unit; a plurality of transfer units connected to the outdoor unit through an air pipe and a liquid pipe; a plurality of indoor units; a plurality of the indoor units are connected one-to-one with a plurality of the transfer units; a waste heat recovery pipe, which is arranged between the plurality of the transfer units and is used to recover waste heat between the transfer units.

[0006] Each of the transfer units is connected to each of the indoor units in a one-to-one correspondence, thereby achieving the purpose of a single transfer unit controlling a single indoor unit. Compared with a centralized transfer unit, the limitation of the distance between the transfer unit and the indoor unit is avoided. Furthermore, the waste heat recovery pipe can recover the waste heat between the transfer units, avoiding heat waste and effectively improving the use efficiency of the air conditioner.

[0007] Furthermore, in one embodiment of the present invention, each of the transfer units includes a gas-liquid separator, and when the outdoor unit is in a cooling-dominated mode, the high-pressure refrigerant is separated into high-pressure gaseous refrigerant and high-pressure liquid refrigerant by the gas-liquid separator. If any of the indoor units is in a heating mode, the high-pressure gaseous refrigerant is delivered to it, and if any of the indoor units is in a cooling mode, the high-pressure liquid refrigerant is delivered to it.

[0008] The setting of the gas-liquid separator can separate the high-pressure refrigerant, so that it can provide high-pressure liquid refrigerant to the indoor unit in cooling mode and provide high-pressure gaseous refrigerant to the indoor unit in heating mode. The purpose of simultaneous cooling and heating of the multi-split air conditioner is achieved by separating the high-pressure liquid refrigerant and the high-pressure gaseous refrigerant, thereby improving the cooling or heating efficiency of the air conditioner.

[0009] Furthermore, in one embodiment of the present invention, the liquid refrigerant of the indoor unit in the heating mode is transported to the indoor unit in the cooling mode through the waste heat recovery pipe.

[0010] Through the setting of the waste heat recovery pipe, the high-pressure liquid generated by the indoor unit in the heating mode can be transported to the indoor unit in the cooling mode, thereby achieving the purpose of waste heat recovery between transfer units. In this mode, the cooling efficiency of the indoor unit in the cooling mode is improved.

[0011] Furthermore, in one embodiment of the present invention, the gas-liquid separator is arranged between the liquid pipe and the indoor unit, and the gas-liquid separator includes an inlet, a gas outlet and an outlet, the outlet of the gas-liquid separator of the indoor unit in cooling mode is connected to the refrigerant inlet of the indoor unit, and the gas outlet is connected to the gas pipe; the outlet of the gas-liquid separator of the indoor unit in heating mode is connected to the refrigerant inlet of the indoor unit in cooling mode through the waste heat recovery pipe; the inlet is connected to the liquid pipe.

[0012] The liquid pipe is connected to the inlet of the gas-liquid separator to provide high-pressure refrigerant for the gas-liquid separator, and the gas-liquid separator provides high-pressure liquid refrigerant or high-pressure gaseous refrigerant for the indoor unit to achieve heating or cooling of different indoor units. The setting of multiple openings of the gas-liquid separator can better realize the full utilization of heat between different indoor units and improve the heating and cooling effects of the air conditioner.

[0013] Furthermore, in one embodiment of the present invention, the refrigerant outlet of the indoor unit in the heating mode is connected to the refrigerant inlet of the indoor unit in the cooling mode through the waste heat recovery pipe.

[0014] The refrigerant outlet of the indoor unit in heating mode is connected to the refrigerant inlet of the indoor unit in cooling mode through the waste heat recovery pipe, providing high-pressure refrigerant for the indoor unit in cooling mode, further enhancing the cooling efficiency of the indoor unit in cooling mode.

[0015] Furthermore, in one embodiment of the present invention, each of the transfer units includes a jet pump, and when the outdoor unit is in heating as the main mode, if any of the indoor units is in heating mode, high-pressure gaseous refrigerant is transported thereto, and a portion of the high-pressure liquid refrigerant passing through the indoor unit is transported to the liquid pipe; the other portion is transported to the transfer unit of the indoor unit in cooling mode through the waste heat recovery pipe.

[0016] In another case, when the outdoor unit is in the heating-dominant mode, it provides high-pressure gaseous refrigerant to the indoor unit in the heating mode, and then transports the high-pressure liquid refrigerant converted by the indoor unit to the indoor unit in the cooling mode. In this state, the waste heat recovery between the transfer units is fully realized, which reduces the waste of resources and improves the efficiency of the air conditioner.

[0017] Furthermore, in one embodiment of the present invention, a portion of the high-pressure liquid refrigerant in the transfer unit of the waste heat recovery pipe is transported to the indoor unit in cooling mode; the other portion is transported to the jet pump; wherein the high-pressure liquid refrigerant transported to the jet pump is used to drain the low-pressure gaseous refrigerant generated by the indoor unit in cooling mode.

[0018] The indoor unit in cooling mode converts high-pressure liquid refrigerant into low-pressure gaseous refrigerant, boosts the pressure of the low-pressure gaseous refrigerant through the jet pump, and then delivers it to the liquid pipe. During this process, the low-pressure gaseous refrigerant is mixed with part of the high-pressure liquid refrigerant in the waste heat recovery pipe, avoiding the need to increase the diameter of the piping due to the transportation of low-pressure gaseous refrigerant, thereby reducing the specification requirements of the piping and saving materials.

[0019] Furthermore, in an embodiment of the present invention, each of the transfer units further includes a gas-liquid separator, the gas-liquid separator is disposed between the liquid pipe and the indoor unit, and the gas-liquid separator includes an inlet, a gas outlet and an outlet.

[0020] The provision of the gas-liquid separator further enhances the mixing between the liquid refrigerant and the gaseous refrigerant and can now serve as a liquid storage cavity for the mixed fluid, thereby improving the air conditioning efficiency and further enhancing the mixing of the low-pressure gaseous refrigerant and the high-pressure liquid refrigerant inside the pipeline.

[0021] Furthermore, in one embodiment of the present invention, when the outdoor unit is in heating-dominated mode, the refrigerant outlet of the indoor unit in heating mode is connected to the inlet; the refrigerant outlet of the indoor unit in cooling mode is connected to the inlet via the jet pump; and the outlet is connected to the liquid pipe.

[0022] The jet pump can recover expansion losses and has the beneficial effect of not delivering low-pressure gaseous refrigerant when heating is the main mode.

[0023] Furthermore, in one embodiment of the present invention, the jet pump is provided with: a driving flow inlet, a suction flow inlet and a jet pump outlet; when the outdoor unit is in heating as the main mode, the refrigerant outlet of the indoor unit in cooling mode is connected to the suction flow inlet; the driving flow inlet is connected to the waste heat recovery pipe, and the jet pump outlet is connected to the inlet of the gas-liquid separator.

[0024] Through the drive flow inlet and the suction flow inlet, the high-pressure liquid refrigerant and the low-pressure gaseous refrigerant can be mixed inside the jet pump, and the mixed fluid is further pressurized and finally transported to the liquid pipe through the jet pump outlet. In this process, the low-pressure gaseous refrigerant is absorbed and processed, thereby achieving the purpose of transporting the fluid without increasing the piping diameter, thereby saving costs.

[0025] In summary, after adopting the technical solution of the present invention, the following technical effects can be achieved:

[0026] i) Each of the transfer units is connected to a single indoor unit, thereby avoiding the distance limitation when connecting the indoor unit and the transfer unit;

[0027] ii) The provision of the waste heat recovery pipe can realize the recovery of waste heat between transfer units, further improving the cooling or heating efficiency of the indoor unit;

[0028] iii) The provision of the gas-liquid separator improves the separation of gaseous refrigerant and liquid refrigerant;

[0029] iv) The provision of the jet pump avoids the requirement of increasing the diameter of the delivery pipe due to the delivery of low-pressure gaseous refrigerant when heating is the main mode, thereby further saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic structural diagram of a multi-split air conditioner 100 provided in accordance with a first embodiment of the present invention.

[0031] Figure 2 for Figure 1 The refrigerant flow diagram is shown when the first indoor unit 30 and the second indoor unit 50 are cooling at the same time.

[0032] Figure 3 for Figure 1 The refrigerant flow diagram is shown when the first indoor unit 30 and the second indoor unit 50 are heating at the same time.

[0033] Figure 4 for Figure 1The refrigerant flow diagram is shown when the first indoor unit 30 is cooling and the second indoor unit 50 is heating.

[0034] Figure 5 for Figure 1 The refrigerant flow diagram is shown when the first indoor unit 30 is heating and the second indoor unit 50 is cooling.

[0035] Figure 6 for Figure 5 Schematic diagram of the structure of the second jet pump 42.

[0036] Description of reference numerals:

[0037] 100-multi-split air conditioner; 10-outdoor unit; 11-liquid storage tank; 12-compressor; 13-four-way valve; 14-first heat exchanger; 15-outdoor expansion valve; 20-first transfer unit; 21-first gas-liquid separator; 22-first injection pump; 23-first check valve; 24-second check valve; 25-first solenoid valve; 26-second solenoid valve; 27-first expansion valve; 28-second expansion valve; 30-first indoor unit; 31-second heat exchanger; 32-first indoor expansion valve; 40-second transfer Unit; 41-second gas-liquid separator; 411-gas chamber; 412-liquid chamber; 42-second jet pump; 421-mixing section; 422-second compressor; 423-condenser; 424-evaporator; 43-third check valve; 44-fourth check valve; 45-third solenoid valve; 46-fourth solenoid valve; 47-third expansion valve; 48-fourth expansion valve; 50-second indoor unit; 51-third heat exchanger; 52-second indoor expansion valve; 60-gas pipe; 70-liquid pipe; 80-waste heat recovery pipe. DETAILED DESCRIPTION

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0039] [First embodiment]

[0040] An embodiment of the present invention provides a multi-split air conditioner 100, which includes: an outdoor unit 10, a plurality of transfer units and a plurality of indoor units; wherein the plurality of transfer units are connected to the outdoor unit 10 through an air pipe 60 and a liquid pipe 70; the plurality of indoor units; and the plurality of indoor units are connected one-to-one with the plurality of transfer units.

[0041] Preferably, taking the transfer unit and the indoor unit as an example, see Figure 1-Figure 3, the transfer unit includes: a first transfer unit 20 and a second transfer unit 40; the indoor unit includes: a first indoor unit 30 and a second indoor unit 50; wherein the first transfer unit 20 and the second transfer unit 40 are connected to the outdoor unit 10 through an air pipe 60 and a liquid pipe 70; the first indoor unit 30 is connected to the first transfer unit 20, and the second indoor unit 50 is connected to the second transfer unit; the outdoor unit 10 includes a liquid storage tank 11, a compressor 12, a four-way valve 13, a first heat exchanger 14 and an outdoor expansion valve 15 which are sequentially connected by piping.

[0042] Preferably, a pipe 90 is provided inside the first transfer unit 20 and the second transfer unit 40. The setting of the pipe 90 realizes the connection between the first indoor unit 30, the second indoor unit 50 and the outdoor unit 10. Further, the outdoor unit 10 realizes the heating and cooling effects of the first indoor unit 30 and the second indoor unit 50 through the pipe 90.

[0043] Specifically, the pipeline 90 includes: a first pipeline 91, a second pipeline 92, a third pipeline 93 and a fourth pipeline 94; wherein, the first pipeline 91 and the second pipeline 92 are arranged in the first transfer unit 20, and one end of the first pipeline 91 is connected to the air pipe 60, the second pipeline 92 is connected to the liquid pipe 70, and the first indoor unit 30 is connected between the first pipeline 91 and the second pipeline 92; the third pipeline 93 and the fourth pipeline 94 are arranged in the second transfer unit 40, and the third pipeline 93 is connected to the air pipe 60, the fourth pipeline 94 is connected to the liquid pipe 70, and the second indoor unit 50 is connected between the third pipeline 93 and the fourth pipeline 94; it can be understood that the internal structure of the first transfer unit 20 is consistent with that of the second transfer unit 40; the multi-split air conditioner 100 also includes: a waste heat recovery pipe 80, which is connected between the second pipeline 92 and the fourth pipeline 94.

[0044] Preferably, when there are two transfer units, the gas-liquid separator includes: a first gas-liquid separator 21 and a second gas-liquid separator 41; wherein, the first gas-liquid separator 21 is arranged in the first transfer unit 20, and the second gas-liquid separator 41 is arranged in the second transfer unit 40; further, the first transfer unit 20 also includes: a first jet pump 22; the first gas-liquid separator 21 is arranged on the second pipeline 92, and is located between the waste heat recovery pipe 80 and the liquid pipe 70; the first jet pump 22 is arranged between the first pipeline 91 and the second pipeline 92; further, the first transfer unit 20 is also provided with a first expansion valve 27, a second expansion valve 28, a first solenoid valve 25 and a second solenoid valve 26, which are used to control the flow of refrigerant inside the first transfer unit 20.

[0045] Furthermore, the first transfer unit 20 is also provided with a first check valve 23 and a second check valve 24, which are respectively arranged between the first pipe 91 and the first jet pump 22, and between the second pipe 92 and the first jet pump 22, for controlling the flow of refrigerant inside the first transfer unit 20 between the first pipe 91, the second pipe 92 and the first jet pump 22, and the first check valve 23 and the second check valve 24 are arranged in opposite directions.

[0046] Furthermore, the first indoor unit 30 is provided with a second heat exchanger 31, the second indoor unit 50 is provided with a third heat exchanger 51, and a first indoor expansion valve 32 is provided on the second pipe 92 connected to the second heat exchanger 31, and a second indoor expansion valve 52 is provided on the fourth pipe 94 connected to the third heat exchanger 51.

[0047] Preferably, the structures and connection relationships of the second indoor unit 50 and the second transfer unit 40 are consistent with those of the first indoor unit 30 and the first transfer unit 20, and are not described in detail here.

[0048] Preferably, when the first indoor unit 30 and the second indoor unit 50 are cooling at the same time, the outdoor unit 10 delivers high-pressure liquid refrigerant to the first indoor unit 30 and the second indoor unit 50 through the liquid pipe 70. Specifically, the high-pressure liquid refrigerant in the liquid pipe 70 is delivered to the second pipe 92 and the fourth pipe 94 of the first transfer unit 20 and the second transfer unit 40, and then the first indoor expansion valve 32 and the second indoor expansion valve 52 convert the high-pressure liquid refrigerant into a low-temperature and low-pressure two-phase refrigerant that is easy to evaporate, wherein the low-pressure two-phase refrigerant includes a low-pressure liquid refrigerant and Low-pressure gaseous refrigerant; further, the low-pressure two-phase refrigerant is further passed through the second heat exchanger 31 and the third heat exchanger 51 to complete heat exchange, thereby achieving the cooling effect of the first indoor unit 30 and the second indoor unit 50; the low-pressure gaseous refrigerant generated by heat exchange between the second heat exchanger 31 and the third heat exchanger 51 is then transported to the air pipe 60 by the first pipeline 91 and the third pipeline 93, and further, is transported to the outdoor unit 10; wherein A is high-pressure gaseous refrigerant, B is high-pressure liquid refrigerant, C is low-pressure two-phase refrigerant, D is low-pressure gaseous refrigerant, and E is high-pressure two-phase refrigerant.

[0049] Furthermore, during the simultaneous cooling of the first indoor unit 30 and the second indoor unit 50, the first solenoid valve 25 and the first expansion valve 27 in the first transfer unit 20 are in an open state, and the second expansion valve 28 and the second solenoid valve 26 are in a closed state; similarly, in the second transfer unit 40, the third solenoid valve 45 and the third expansion valve 47 are in an open state, and the fourth solenoid valve 46 and the fourth expansion valve 48 are in a closed state.

[0050] It can be understood that during the simultaneous cooling process of the first indoor unit 30 and the second indoor unit 50, the operating states of the first indoor unit 30 and the second indoor unit 50 are consistent. Therefore, at this time, the jet pump and the gas-liquid separator in the first transfer unit 20 and the second transfer unit 40 are not in a working state. During the simultaneous cooling process, the multi-split air conditioner 100 is consistent with the operation process of the connected air conditioner in the prior art, and the specific operation process will not be repeated here.

[0051] Preferably, the first indoor unit 30 and the second indoor unit 50 are in accordance with the principle of simultaneous heating and simultaneous cooling. When the first indoor unit 30 and the second indoor unit 50 are heating at the same time, the outdoor unit 10 transports high-pressure gaseous refrigerant to the first indoor unit 30 and the second indoor unit 50 through the air pipe 60; specifically, the high-pressure gaseous refrigerant in the air pipe 60 is transported to the first pipe 91 and the third pipe 93 of the first transfer unit 20 and the second transfer unit 40, and then passes through the second heat exchanger 31 and the third heat exchanger 51 to complete the heat exchange. After the heat exchange is completed, the generated high-pressure liquid refrigerant is transported to the liquid pipe 70 through the second pipe 92 and the fourth pipe 94, and is further transported back to the outdoor unit 10 through the liquid pipe 70.

[0052] Furthermore, during simultaneous heating and cooling, except that the gas-liquid flow directions between the first indoor unit 30, the second indoor unit 50 and the outdoor unit 10 are opposite, the closing states of the switches in the first transfer unit 20 and the second transfer unit 40 are also consistent with those under simultaneous cooling conditions, which will not be described in detail here.

[0053] [Second embodiment]

[0054] Preferably, the second embodiment of the present invention provides another multi-split air conditioner 100, in which the outdoor unit 10 is in the cooling-dominated mode, the high-pressure refrigerant is separated into high-pressure gaseous refrigerant and high-pressure liquid refrigerant by the gas-liquid separator, and if any of the indoor units is in the heating mode, the high-pressure gaseous refrigerant is delivered to it, and if any of the indoor units is in the cooling mode, the high-pressure liquid refrigerant is delivered to it. The liquid refrigerant of the indoor unit in the heating mode is delivered to the indoor unit in the cooling mode through the waste heat recovery pipe 80. The gas-liquid separator is arranged between the liquid pipe 70 and the indoor unit, and the gas-liquid separator includes an inlet, a gas outlet and an outlet. The outlet of the gas-liquid separator of the indoor unit in cooling mode is connected to the refrigerant inlet of the indoor unit, and the gas outlet is connected to the gas pipe 60; the gas outlet of the gas-liquid separator of the indoor unit in heating mode is connected to the refrigerant inlet of the indoor unit, and the outlet is connected to the refrigerant inlet of the indoor unit in cooling mode through the waste heat recovery pipe 80; the inlet is connected to the liquid pipe 70; the refrigerant outlet of the indoor unit in heating mode is connected to the refrigerant inlet of the indoor unit in cooling mode through the waste heat recovery pipe 80.

[0055] The cooling mode is the main mode, which means that when the multi-split air conditioner 100 is operating in cooling and heating at the same time, Figure 4 For example, the first indoor unit 30 has a larger cooling demand, and the second indoor unit 50 has a relatively smaller heating demand. At this time, the multi-split air conditioner 100 is mainly based on cooling, that is, the operating state of the multi-split air conditioner 100 can be recorded as: cooling is the main mode, and in this state, the outdoor unit 10 is heating; it can be understood that in the cooling-dominant mode, the second indoor unit 50 can be regarded as the second outdoor unit of the first indoor unit 30, and through the cooperation between the second indoor unit 50 and the outdoor unit 10, the high-pressure liquid refrigerant is transported to the first indoor unit 30 by the liquid pipe 70 and the waste heat recovery pipe 80, so as to improve the cooling efficiency of the first indoor unit 30, and further meet the user's demand for cooling in the cooling-dominant mode.

[0056] Furthermore, when there are two indoor units and two transfer units respectively, when the multi-split air conditioner 100 performs cooling and heating simultaneously, in the main cooling mode of the outdoor unit 10, the first indoor unit 30 performs cooling and the second indoor unit 50 performs heating is taken as an example;

[0057] See also Figure 4 In the cooling-dominated mode, by suppressing the fan air volume of the first heat exchanger 14 in the outdoor unit 10, a high-pressure two-phase refrigerant can be generated in the outdoor unit 10 piping, that is, high-pressure gaseous refrigerant and high-pressure liquid refrigerant exist at the same time, and the high-pressure two-phase refrigerant is transported from the second pipeline 92 to the first gas-liquid separator 21 through the liquid pipe 70. After gas-liquid separation by the first gas-liquid separator 21, the high-pressure liquid refrigerant is transported to the first indoor unit 30 by the first expansion valve 27, and then reduced in pressure by the first indoor expansion valve 32 to generate a low-pressure two-phase refrigerant, which enters the second heat exchanger 31, thereby achieving the purpose of cooling the first indoor unit 30. The low-pressure gaseous refrigerant after further heat exchange in the second heat exchanger 31 is transported to the air pipe 60 by the first pipeline 91, and finally transported back to the interior of the outdoor unit 10, thereby forming a cycle.

[0058] Furthermore, during the cooling process of the first indoor unit 30, the first solenoid valve 25 in the first transfer unit 20 is in an open state, the second solenoid valve 26 is in a closed state, the first expansion valve 27 is in an open state, the second expansion valve 28 is in an open state and the valve opening of the second expansion valve 28 is adjusted to be smaller, so that it can reduce the pressure of the high-pressure gaseous refrigerant flowing from the first gas-liquid separator 21 to the first pipeline 91, and further mix with the low-pressure gaseous refrigerant in the first pipeline 91, and then be transported to the outdoor unit 10 through the gas pipe 60.

[0059] Preferably, when the second indoor unit 50 is heating, the high-pressure two-phase refrigerant in the liquid pipe 70 is transported to the second gas-liquid separator 41 by the fourth pipe 94, and then after gas-liquid separation, the high-pressure gaseous refrigerant is transported to the third pipe 93 through the fourth expansion valve 48, and further transported to the second indoor unit 50 for heat exchange, and forms a high-pressure liquid refrigerant after completing the heat exchange through the third heat exchanger 51; in order to ensure the full utilization of the high-pressure liquid refrigerant in the second indoor unit 50, the high-pressure liquid refrigerant can be transported to the first indoor unit 30 through the waste heat recovery pipe 80, and further refrigeration treatment is performed by the first indoor unit 30; the high-pressure liquid refrigerant separated by the second gas-liquid separator 41 can be transported to the waste heat recovery pipe 80 by the third expansion valve 47, and after mixing with the high-pressure liquid refrigerant generated by the second indoor unit 50, it is transported to the first indoor unit 30. In this process, the waste of high-pressure liquid refrigerant generated when the second indoor unit 50 is heating is avoided.

[0060] Furthermore, during the heating process of the second indoor unit 50, the third solenoid valve 45 and the fourth solenoid valve 46 are in a closed state, and the fourth expansion valve 48 is in a fully open state; in order to prevent the high-pressure liquid refrigerant separated by the second gas-liquid separator 41 from affecting the heating of the second indoor unit 50, the opening of the third expansion valve 47 is adjusted to be smaller.

[0061] Preferably, in one case, when cooling is the main mode and the heating requirement is relatively low, the first gas-liquid separator 21 and the second gas-liquid separator 41 in the first transfer unit 20 and the second transfer unit 40 can be omitted. The high-pressure liquid refrigerant (for example, condensation temperature 50°C) from the outdoor unit 10 can flow into the first indoor unit 30 and the second indoor unit 50, and only the sensible heat is used for heating, that is, when the second indoor unit 50 is heating, the temperature of the high-pressure liquid refrigerant is used for heating, and in this process, the refrigerant state does not undergo a phase change.

[0062] [Third embodiment]

[0063] Preferably, the third embodiment of the present invention provides another multi-split air conditioner 100. In the embodiment of the present invention, each of the transfer units includes a jet pump. When the outdoor unit 10 is in the heating-dominant mode, if any of the indoor units is in the heating mode, a high-pressure gaseous refrigerant is delivered to it, and a part of the high-pressure liquid refrigerant passing through the indoor unit is delivered to the liquid pipe; the other part is delivered to the transfer unit of the indoor unit in the cooling mode through the waste heat recovery pipe 80. A part of the high-pressure liquid refrigerant delivered to the transfer unit of the indoor unit in the cooling mode by the waste heat recovery pipe 80 is delivered to the indoor unit in the cooling mode; the other part is delivered to the jet pump; wherein the high-pressure liquid refrigerant delivered to the jet pump is used to drain the low-pressure gaseous refrigerant generated by the indoor unit in the cooling mode. When the outdoor unit 10 is in the heating-dominant mode, the refrigerant outlet of the indoor unit in the heating mode is connected to the inlet of the gas-liquid separator; the refrigerant outlet of the indoor unit in the cooling mode is connected to the inlet through the jet pump; the outlet of the gas-liquid separator is connected to the liquid pipe. The jet pump is provided with: a driving flow inlet, a suction flow inlet and a jet pump outlet; when the outdoor unit 10 is in the heating-dominated mode, the refrigerant outlet of the indoor unit in the cooling mode is connected to the suction flow inlet; the driving flow inlet is connected to the waste heat recovery pipe 80; the jet pump outlet is connected to the inlet of the gas-liquid separator.

[0064] Among them, heating is the main mode, which means: when the multi-split air conditioner 100 operates in cooling and heating at the same time, Figure 5 For example, the first indoor unit 30 has a larger heating demand, and the second indoor unit 50 has a relatively smaller cooling demand. At this time, the multi-split air conditioner 100 is mainly used for heating, that is, the operating state of the multi-split air conditioner 100 can be recorded as: heating is the main mode, and in this state, the outdoor unit 10 is cooling; it can be understood that in the heating-main mode, the user's demand for cooling is relatively low, and the first indoor unit 30 can be used as the external unit of the second indoor unit 50. The first indoor unit 30 can provide the high-pressure liquid refrigerant required by the second indoor unit 50. At this time, the waste heat recovery pipe 80 mainly plays the role of transporting high-pressure liquid refrigerant to the second indoor unit 50.

[0065] For further information, see Figure 5When there are two indoor units and two transfer units respectively, when heating is the main mode, take the first indoor unit 30 for heating and the second indoor unit 50 for cooling as an example: the outdoor unit 10 transmits high-pressure gaseous refrigerant to the first indoor unit 30 through the gas pipe 60 from the first pipeline 91, and forms high-pressure liquid refrigerant after heat exchange with indoor air in the second heat exchanger 31, wherein a part of the generated high-pressure liquid refrigerant is transmitted from the second pipeline 92 through the first expansion valve 27 to the liquid pipe 70, and then transmitted from the liquid pipe 70 back to the outdoor unit 10 to form a cycle; another part of the generated high-pressure liquid refrigerant is transmitted from the second pipeline 92 through the waste heat recovery pipe 80 It is transported to the second transfer unit 40, further reduced in pressure by the second indoor expansion valve 52, and heat exchanged by the third heat exchanger 51. It is then transported back to the outdoor unit 10 by the third pipeline 93 through the third check valve 43, the second jet pump 42, the fourth solenoid valve 46, the second gas-liquid separator 41 and the liquid pipe 70 to complete the cycle; at the same time, another part of the high-pressure liquid refrigerant transported to the second transfer unit 40 by the second pipeline 92 is transported back to the outdoor unit 10 by the fourth pipeline 94 through the fourth check valve 44, the second jet pump 42, the fourth solenoid valve 46, the second gas-liquid separator 41 and the liquid pipe 70 to complete the cycle.

[0066] Furthermore, during the heating process of the first indoor unit 30, the first solenoid valve 25 in the first transfer unit 20 is in an open state, the second solenoid valve 26 is in a closed state, the first expansion valve 27 is in an open state and the valve opening of the first expansion valve 27 is small, and the second expansion valve 28 is in a closed state.

[0067] Furthermore, during the cooling process of the second indoor unit 50, the third solenoid valve 45 is in a closed state, the fourth solenoid valve 46 is in an open state, and the third expansion valve 47 and the fourth expansion valve 48 are in a closed state.

[0068] Preferably, when heating is the main mode, the high-pressure liquid refrigerant transported in the second transfer unit is mostly distributed to the second jet pump 42 side as the driving flow of the refrigerant transported to the second indoor unit 50. In addition, the refrigerant transported to the second indoor unit 50 is returned to the outdoor unit 10 through the liquid pipe 70 after being evaporated and pressurized by the second jet pump 42. The second expansion valve 28 in the first transfer unit 20 used for heating can be adjusted to be fully closed in order to allow the return liquid refrigerant to flow to the second transfer unit 40 on the cooling side, but the opening degree needs to be adjusted according to the proportion of cooling (such as when the pressure loss of the third pipe 93 and the fourth pipe 94 used for cooling is too large).

[0069] Preferably, see Figure 6When heating is the main mode, the second indoor unit 50 is in cooling mode, and the high-pressure liquid refrigerant flowing from the fourth check valve 44 to the second jet pump 42 is ejected at high speed by the nozzle as a driving flow, forming a low-pressure space inside, and the low-pressure gaseous refrigerant flowing from the third check valve 43 to the second jet pump 42 is sucked into the second jet pump 42 as a suction flow, and mixed in the mixing section 421 of the second jet pump 42. The mixed fluid reduces its speed in the diffuser while restoring its kinetic energy almost without loss, thereby further achieving the purpose of restoring pressure.

[0070] Among them, P H is the initial pressure value when the high-pressure liquid refrigerant as the driving flow enters the second jet pump 42, P L is the initial pressure value when the low-pressure gaseous refrigerant as the suction flow enters the second jet pump 42, P S P is the minimum pressure value reached after the driving flow and the suction flow are mixed. D is the pressure value of the mixed fluid at the outlet of the second jet pump 42.

[0071] Furthermore, it is transported to the gas chamber 411 and the liquid chamber 412 in the second gas-liquid separator 41. At this time, since the fourth expansion valve 48 is in a closed state, the separated gaseous refrigerant will not enter the gas pipe 60 from the fourth expansion valve 48. At this time, the second gas-liquid separator 41 can be used as a storage device. When the low-pressure gaseous refrigerant and the high-pressure liquid refrigerant in the second jet pump 42 cannot be fully mixed, the mixed fluid can be further buffered in the second gas-liquid separator 41, and finally the final mixed fluid is transported to the liquid pipe 70, and further transported to the outdoor unit 10 to realize circulation. It can be understood that the mixed fluid is mainly high-pressure liquid, with a small amount of gas mixed therein; the mixed fluid passing through the second gas-liquid separator 41 can also be separated by adding piping, and further transported to the second compressor 422 and the condenser 423 by the newly arranged piping to achieve the purpose of heating or cooling through the evaporator. In this process, the cooling or heating process is consistent with the method in the prior art, and will not be repeated here.

[0072] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A multi-split air conditioner, characterized in that: include: Outdoor unit (10); A plurality of transfer units connected to the outdoor unit via an air pipe (60) and a liquid pipe (70); A plurality of indoor units are connected to the plurality of transfer units in a one-to-one correspondence; A waste heat recovery pipe (80) is arranged between the plurality of transfer units and is used to recover waste heat between the transfer units; Each of the transfer units comprises a gas-liquid separator, and when the outdoor unit (10) is in a cooling-dominated mode, the high-pressure refrigerant is separated into a high-pressure gaseous refrigerant and a high-pressure liquid refrigerant by the gas-liquid separator; if any of the indoor units is in a heating mode, the high-pressure gaseous refrigerant is delivered to it; and if any of the indoor units is in a cooling mode, the high-pressure liquid refrigerant is delivered to it; The gas-liquid separator is arranged between the liquid pipe (70) and the indoor unit, and the gas-liquid separator includes an inlet, a gas outlet and an outlet. The outlet of the gas-liquid separator of the indoor unit in cooling mode is connected to the refrigerant inlet of the indoor unit, and the gas outlet is connected to the gas pipe (60); the gas outlet of the gas-liquid separator of the indoor unit in heating mode is connected to the refrigerant inlet of the indoor unit, and the outlet is connected to the refrigerant inlet of the indoor unit in cooling mode through the waste heat recovery pipe (80); the inlet is connected to the liquid pipe (70).

2. The multi-split air conditioner according to claim 1, characterized in that: The liquid refrigerant of the indoor unit in the heating mode is transported to the indoor unit in the cooling mode through the waste heat recovery pipe (80).

3. The multi-split air conditioner according to claim 1, characterized in that: The refrigerant outlet of the indoor unit in the heating mode is connected to the refrigerant inlet of the indoor unit in the cooling mode through the waste heat recovery pipe (80).

4. The multi-split air conditioner according to claim 1, characterized in that: Each of the transfer units comprises a jet pump. When the outdoor unit (10) is in the heating-dominated mode, if any of the indoor units is in the heating mode, high-pressure gaseous refrigerant is delivered to it. A portion of the high-pressure liquid refrigerant passing through the indoor unit is delivered to the liquid pipe; the other portion is delivered to the transfer unit of the indoor unit in the cooling mode through the waste heat recovery pipe (80).

5. The multi-split air conditioner according to claim 4, characterized in that: A portion of the high-pressure liquid refrigerant transported by the waste heat recovery pipe (80) to the transfer unit of the indoor unit in cooling mode is transported to the indoor unit in cooling mode; the other portion is transported to the jet pump; The high-pressure liquid refrigerant delivered to the jet pump is used to guide the low-pressure gaseous refrigerant generated by the indoor unit in the cooling mode.

6. The multi-split air conditioner according to claim 5, characterized in that: Each of the transfer units further comprises a gas-liquid separator, the gas-liquid separator being arranged between the liquid pipe (70) and each of the indoor units, the gas-liquid separator comprising an inlet, a gas outlet and an outlet.

7. The multi-split air conditioner according to claim 6, characterized in that: When the outdoor unit (10) is in a heating-dominated mode, the refrigerant outlet of the indoor unit in the heating mode is connected to the inlet of the gas-liquid separator; the refrigerant outlet of the indoor unit in the cooling mode is connected to the inlet via the jet pump; and the outlet of the gas-liquid separator is connected to the liquid pipe.

8. The multi-split air conditioner according to any one of claims 6-7, characterized in that: The jet pump is provided with: a driving flow inlet, a suction flow inlet and a jet pump outlet; The outdoor unit (10) is in heating-dominated mode, and the refrigerant outlet of the indoor unit in cooling mode is connected to the suction inlet; the drive inlet is connected to the waste heat recovery pipe (80); and the jet pump outlet is connected to the inlet of the gas-liquid separator.

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