Multi-connected air conditioning system

Abstract

The present invention relates to the field of air conditioning technology, and in particular to a multi-connected air conditioning system. The present invention aims to solve the problem of high investment cost of independently setting up two sets of air conditioning systems. The multi-connected air conditioning system includes an outdoor heat exchanger, at least one first indoor heat exchanger for a room other than a machine room, at least one second indoor heat exchanger for a machine room, a first four-way valve, a first compressor, and the same number of second four-way valves and second compressors as the second indoor heat exchangers. The first end of each first heat exchanger is connected to the first end of the outdoor heat exchanger, and the second end is connected to the second end of the outdoor heat exchanger through the first four-way valve and the first compressor; the first end of each second heat exchanger is connected to the first end of the outdoor heat exchanger, and the second end is connected to the second end of the outdoor heat exchanger through a second four-way valve and a second compressor. By connecting the first / second indoor heat exchanger to the outdoor heat exchanger at the same time, the outdoor unit is shared, which reduces the cost.

Description

Technical Field

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

[0002] With the advancement of information technology in today's society, there are more and more small and medium-sized data centers. These data centers or small computer rooms are mostly located in a room adjacent to the office area in the office building. Since the office area and the electronic equipment in the computer room have different requirements for the adjustment of environmental parameters, that is, the office area requires a warm indoor environment in winter and cool in summer, while the electronic equipment in the computer room needs to maintain a constant temperature and humidity indoor environment throughout the year, two independent air conditioning systems are usually installed in the office building: one is a multi-connected comfort air conditioning system that provides cooling in summer and heating in winter for the office area, and the other is a computer room air conditioning system that provides constant temperature and humidity operation for electronic equipment throughout the year.

[0003] Although the above two independently set air conditioning systems solve the problem of different environmental parameter adjustment requirements in different areas, there are also some corresponding defects, which are mainly manifested in: first, the two independently set air conditioning systems need to install outdoor units outside the building respectively, especially the machine room air conditioning system, because it is generally a one-to-one unit product, the indoor unit and the outdoor unit correspond one to one. If multiple units are installed in a machine room at the same time, it will cause multiple outdoor units to be installed outside the building at the same time, which not only affects the beauty of the building, but also has the problems of cumbersome initial construction, high investment cost and complex later operation and maintenance; secondly, the two independently operated air conditioning systems cannot perform comprehensive energy management, which also leads to defects such as energy waste and high operating costs. In other words, the two independently set air conditioning systems used in the prior art have the problems of high investment cost and large energy waste.

[0004] Accordingly, the art needs a new air conditioning system to solve the above problems. Summary of the invention

[0005] In order to solve the above-mentioned problems in the prior art, that is, to solve the problems of high investment cost and large energy waste in the prior art of using two sets of independently set air-conditioning systems for office areas and computer rooms, the present invention provides a multi-connected air-conditioning system, including an outdoor heat exchanger, a first indoor heat exchanger group for cooling or heating indoor spaces other than computer rooms, a second indoor heat exchanger group for cooling or heating computer rooms, a first four-way valve, a first compressor, a second four-way valve group and a second compressor group, wherein the first indoor heat exchanger group includes at least one first indoor heat exchanger, the second indoor heat exchanger group includes at least one second indoor heat exchanger, and the second four-way valve group includes a second compressor group connected to the second indoor heat exchanger. The second four-way valve has the same number of second indoor heat exchangers, and the second compressor group includes the same number of second compressors as the second four-way valves; wherein the first end of each of the first indoor heat exchangers is connected to the first end of the outdoor heat exchanger, and the second end of each of the first indoor heat exchangers is connected to the second end of the outdoor heat exchanger through the first four-way valve and the first compressor; wherein the first end of each of the second indoor heat exchangers is connected to the first end of the outdoor heat exchanger, and the second end of each of the second indoor heat exchangers is connected to the second end of the outdoor heat exchanger or the second end of the first indoor heat exchanger group through a second four-way valve and a second compressor.

[0006] In the preferred technical solution of the above-mentioned multi-split air-conditioning system, the second indoor heat exchanger group includes multiple second indoor heat exchangers, and the second compressor group and the second four-way valve group respectively include the same number of second compressors and second four-way valves as the second indoor heat exchangers.

[0007] In the preferred technical solution of the above-mentioned multi-split air-conditioning system, the multi-split air-conditioning system also includes a first solenoid valve and a second solenoid valve having the same number as the second indoor heat exchanger, the first solenoid valve selectively connecting the exhaust side of the first compressor with the exhaust side of the second compressor, and the second solenoid valve selectively connecting the intake side of the first compressor with the intake side of the second compressor.

[0008] In a preferred technical solution of the above-mentioned multi-connected air-conditioning system, the first indoor heat exchanger group includes a plurality of first indoor heat exchangers, and the plurality of first indoor heat exchangers are connected in parallel with each other.

[0009] In the preferred technical solution of the above multi-connected air-conditioning system, a first expansion valve is further provided between the outdoor heat exchanger and each of the first indoor heat exchangers.

[0010] In a preferred technical solution of the above multi-connected air-conditioning system, a second expansion valve is further provided between the outdoor heat exchanger and each of the second indoor heat exchangers.

[0011] In the preferred technical solution of the above-mentioned multi-split air-conditioning system, the outdoor heat exchanger, the first four-way valve and the first compressor are arranged in the outdoor unit of the multi-split air-conditioning system, each of the first indoor heat exchangers is arranged in the first indoor unit of the multi-split air-conditioning system, and each of the second indoor heat exchanger, the second four-way valve and the second compressor is arranged in the second indoor unit of the multi-split air-conditioning system.

[0012] In the preferred technical solution of the above-mentioned multi-connected air-conditioning system, the first indoor unit is also provided with a first controller and a first temperature sensor, and the first controller is used to control the opening of the first expansion valve according to the indoor temperature detected by the first temperature sensor; and / or adjust the direction of the first four-way valve; and / or control the start and stop of the first compressor.

[0013] In the preferred technical solution of the above-mentioned multi-split air-conditioning system, the second indoor unit is also provided with a second controller and a second temperature sensor, and the second controller is used to adjust the opening of the second expansion valve according to the room temperature detected by the second temperature sensor; and / or adjust the direction of the second four-way valve; and / or control the start and stop of the second compressor.

[0014] In the preferred technical solution of the above-mentioned multi-connected air-conditioning system, the second controller is also used to control the opening and closing of the first solenoid valve and / or the second solenoid valve.

[0015] It can be understood by those skilled in the art that in the preferred technical solution of the present invention, the multi-connected air conditioning system includes an outdoor heat exchanger, a first indoor heat exchanger group for cooling or heating the non-machine room indoor, a second indoor heat exchanger group for cooling or heating the machine room, a first four-way valve, a first compressor, a second four-way valve group and a second compressor group. Among them, the first indoor heat exchanger group includes at least one first indoor heat exchanger, the first end of each first indoor heat exchanger is connected to the first end of the outdoor heat exchanger, and the second end of each first indoor heat exchanger is connected to the second end of the outdoor heat exchanger through the first four-way valve and the first compressor. Among them, the second indoor heat exchanger group includes at least one second indoor heat exchanger, and the second compressor group and the second four-way valve group respectively include the same number of second compressors and second four-way valves as the second indoor heat exchangers. The first end of each second indoor heat exchanger is connected to the first end of the outdoor heat exchanger, and the second end of each second indoor heat exchanger is connected to the second end of the outdoor heat exchanger or the second end of the first indoor heat exchanger group through a second four-way valve and a second compressor. Through the above-mentioned setting mode, the multi-connected air-conditioning system of the present invention realizes the combination of the non-machine room air-conditioning system and the machine room air-conditioning system, so that the first indoor heat exchanger and the second indoor heat exchanger share an outdoor heat exchanger, solving the problems of high investment cost and large energy waste in the prior art of using two independently set air-conditioning systems. Furthermore, each second indoor heat exchanger is connected to a second four-way valve and a second compressor, which can not only enhance the refrigerant circulation of the second indoor heat exchanger, but also the second compressor and the second four-way valve can also serve as a redundant design of the first compressor and the first four-way valve, thereby improving the operating stability of the multi-connected air-conditioning system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The multi-split air conditioning system of the present invention is described below with reference to the accompanying drawings and in combination with the application scenarios of offices and data centers.

[0017] Figure 1 It is a structural schematic diagram of the multi-connected air conditioning system of the present invention;

[0018] Figure 2A It is a schematic diagram of the working principle of the multi-connected air conditioning system of the present invention in office cooling and computer room cooling modes;

[0019] Figure 2B It is a schematic diagram of the working principle of the multi-connected air conditioning system of the present invention in office cooling and computer room heating modes;

[0020] Figure 2C It is a schematic diagram of the working principle of the multi-connected air conditioning system of the present invention in office heating and computer room heating modes;

[0021] Figure 2D The figure is a schematic diagram of the working principle of the multi-connected air conditioning system of the present invention in the office heating and computer room cooling modes.

[0022] Reference numerals list

[0023] 11. outdoor heat exchanger; 21. first indoor heat exchanger group; 211. first indoor heat exchanger; 22. second indoor heat exchanger group; 221. second indoor heat exchanger; 31. first four-way valve; 32. second four-way valve group; 321. second four-way valve; 41. first compressor; 42. second compressor group; 421. second compressor; 51. first expansion valve; 52. second expansion valve; 61. first solenoid valve; 62. second solenoid valve. DETAILED DESCRIPTION

[0024] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. For example, although the accompanying drawings describe two first indoor heat exchangers and two second indoor heat exchangers, this arrangement is not static, and those skilled in the art can adjust it as needed to adapt to specific applications. For example, one or three first indoor heat exchangers can be set in the office, and one or three second indoor heat exchangers can be set in the machine room, etc.

[0025] It should be noted that in the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0026] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] First refer to Figure 1 , Figure 1 FIG. 1 is a schematic diagram of the structure of the multi-connected air conditioning system of the present invention. Figure 1As shown, in order to solve the problems of high investment cost and large energy waste in the prior art of using two sets of independent air conditioning systems for office area and computer room, the multi-connected air conditioning system of the present invention includes an outdoor heat exchanger 11, a first indoor heat exchanger group 21 for cooling or heating the office, a second indoor heat exchanger group 22 for cooling or heating the computer room, a first four-way valve 31, a first compressor 41, a second four-way valve group 32 and a second compressor group 42. The first indoor heat exchanger group 21 includes two first indoor heat exchangers 211 connected in parallel, and the first end ( Figure 1 The left end of the first indoor heat exchanger 211 in parallel) and the first end of the outdoor heat exchanger 11 ( Figure 1 The upper end of the middle outdoor heat exchanger 11 is connected, and the second end ( Figure 1 The first end of the first indoor heat exchanger 211 in parallel) is connected to the first compressor 41 and the second end of the outdoor heat exchanger 11 through the first four-way valve 31 ( Figure 1 The second indoor heat exchanger group 22 includes two second indoor heat exchangers 221 connected in parallel, the second four-way valve group 32 preferably includes two second four-way valves 321 corresponding to the second indoor heat exchangers 221, the second compressor group 42 preferably includes two second compressors 421 corresponding to the second indoor heat exchangers 221, and the first end ( Figure 1 The left end of the second indoor heat exchanger 221 in parallel) is connected to the first end of the outdoor heat exchanger 11, and the second end of each second indoor heat exchanger 221 ( Figure 1 The right end of the second indoor heat exchanger 221) is connected to the second end of the outdoor heat exchanger 11 or the second end of the first indoor heat exchanger 211 in parallel through a second four-way valve 321 and a second compressor 421.

[0028] Continue to refer to Figure 1 In order to control the refrigerant flow through each first indoor heat exchanger 211 / second indoor heat exchanger 221 in the air-conditioning system, a first expansion valve 51 is further provided between each first indoor heat exchanger 211 and the outdoor heat exchanger 11, and a second expansion valve 52 is further provided between each second indoor heat exchanger 221 and the outdoor heat exchanger 11. In order to realize the separate control of the working modes of the office indoor unit and the computer room indoor unit, the multi-connected air-conditioning system is further provided with two first solenoid valves 61 and two second solenoid valves 62 corresponding to the two second indoor heat exchangers 221, according to Figure 1In terms of orientation, the two first solenoid valves 61 are respectively arranged between the lower port of the first four-way valve 31 and the left ports of the two second four-way valves 321, and are used to selectively connect the exhaust side of the first compressor 41 with the exhaust side of the second compressor 421. The two second solenoid valves 62 are respectively arranged between the right port of the first four-way valve 31 and the left ports of the two second four-way valves 321, and are used to selectively connect the suction side of the first compressor 41 with the suction side of the second compressor 421, that is, to realize that the second end of each second indoor heat exchanger 221 is connected to the second end of the outdoor heat exchanger 11 or the second end of the first indoor heat exchanger 211 in parallel through a second four-way valve 321 and a second compressor 421.

[0029] In a possible implementation, the outdoor heat exchanger 11, the first four-way valve 31 and the first compressor 41 are arranged in the outdoor unit of the multi-connected air conditioning system, each first indoor heat exchanger 211 is arranged in a first indoor unit (i.e., an office indoor unit) of the multi-connected air conditioning system, and each second indoor heat exchanger 221, the second four-way valve 321 and the second compressor 421 are arranged in a second indoor unit (i.e., an indoor unit of a machine room) of the multi-connected air conditioning system. In other words, Figure 1 The multi-split air conditioning system shown includes an outdoor unit, and two office indoor units and two machine room indoor units connected to the outdoor unit.

[0030] In addition, the office indoor unit is also provided with a first controller (not shown in the figure) and a first temperature sensor (not shown in the figure), and the first controller is used to control the opening of the first expansion valve 51 according to the indoor temperature detected by the first temperature sensor (such as the return air temperature of the office indoor unit); and / or adjust the direction of the first four-way valve; and / or control the start and stop of the first compressor 41. The computer room indoor unit is also provided with a second controller (not shown in the figure) and a second temperature sensor (not shown in the figure), and the second controller is used to adjust the opening of the second expansion valve 52 according to the computer room temperature detected by the second temperature sensor (such as the return air temperature of the computer room indoor unit); and / or control the opening and closing of the first solenoid valve 61 and the second solenoid valve 62; and / or adjust the direction of the second four-way valve 321; and / or control the start and stop of the second compressor 421.

[0031] It can be seen from the above description that by connecting the first indoor heat exchanger 211 of the office indoor unit and the second indoor heat exchanger 221 of the machine room indoor unit to the outdoor heat exchanger 11 of the outdoor unit, the multi-connected air-conditioning system of the present invention can integrate the office air-conditioning system and the machine room air-conditioning system into a set of multi-connected air-conditioning systems, so that the two systems can share the outdoor units on the basis of separate control. This setting method not only saves costs, but also greatly reduces the installation difficulty and maintenance complexity of the multi-connected air-conditioning system. Furthermore, a second four-way valve 321 and a second compressor 421 are set in each second indoor heat exchanger 221 circuit, which can not only enhance the refrigerant circulation of the second indoor heat exchanger 221, but also the second compressor 421 and the second four-way valve 321 can also be used as a redundant design of the first compressor 41 and the first four-way valve 31, thereby improving the operating stability of the multi-connected air-conditioning system.

[0032] Of course, the above-mentioned configuration is only a possible implementation mode of the present invention. Without departing from the principle of the present invention, those skilled in the art can also make flexible adjustments to it so that the present invention can adapt to more specific application scenarios. For example, the two second indoor heat exchangers 221 can also share a second four-way valve 321 and a second compressor 421. In this case, the second four-way valve 321 and the second compressor 421 can be set in the outdoor unit. For another example, the first controller and the second controller can be integrated into one controller.

[0033] Refer to the following FIG. 2A to FIG. 2D ,in Figure 2A It is a schematic diagram of the working principle of the multi-connected air conditioning system of the present invention in office cooling and computer room cooling modes; Figure 2B It is a schematic diagram of the working principle of the multi-connected air conditioning system of the present invention in office cooling and computer room heating modes; Figure 2C It is a schematic diagram of the working principle of the multi-connected air conditioning system of the present invention in office heating and computer room heating modes; Figure 2D The figure is a schematic diagram of the working principle of the multi-connected air conditioning system of the present invention in the office heating and computer room cooling modes.

[0034] like FIG. 2A to FIG. 2D As shown, under the above configuration, the multi-connected air conditioning system of the present invention can be divided into four working modes:

[0035] 1) Office cooling and computer room cooling modes. Figure 2AAs shown, the two first solenoid valves 61 are opened, the two second solenoid valves 62 are closed, and the first four-way valve 31 and the two second four-way valves 321 remain in the initial state. At this time, a part of the refrigerant in the system flows through the outdoor heat exchanger 11, the two first expansion valves 51, the two first indoor heat exchangers 211, the first four-way valve 31 and the first compressor 41 in sequence and then returns to the outdoor heat exchanger 11, completing the refrigeration cycle of the office; another part of the refrigerant in the system flows through the outdoor heat exchanger 11, the two second expansion valves 52, the two second indoor heat exchangers 221, the two second four-way valves 321, the two second compressors 421 and the first four-way valve 31 in sequence and then returns to the outdoor heat exchanger 11, completing the refrigeration cycle of the machine room. For example, in summer, when both the office and the machine room need to be cooled, the air conditioning system operates in the above working mode, and adjusts the office temperature and the machine room temperature by adjusting the opening of the first expansion valve 51, and / or the opening of the second expansion valve 52, and / or the start and stop of the first compressor 41.

[0036] 2) Office cooling and computer room heating mode. Figure 2B As shown, the two first solenoid valves 61 are closed, the two second solenoid valves 62 are opened, the first four-way valve 31 maintains the initial state, and the two second four-way valves 321 are switched. At this time, a part of the refrigerant in the system flows through the outdoor heat exchanger 11, the two first expansion valves 51, the two first indoor heat exchangers 211, the first four-way valve 31 and the first compressor 41 in sequence, and then returns to the outdoor heat exchanger 11, completing the refrigeration cycle of the office; another part of the refrigerant in the system flows through the two first indoor heat exchangers 211, the first four-way valve 31, the two second four-way valves 321, the two second compressors 421, the two second indoor heat exchangers 221, the two second expansion valves 52 and the two first expansion valves 51 in sequence, and then returns to the two first indoor heat exchangers 211, completing the heating cycle of the computer room. For example, in summer, both the office and the computer room are in cooling mode (i.e. Figure 2A The working mode shown in the figure), but the temperature of the machine room is lower than the set temperature. At this time, by closing the first solenoid valve 61, opening the second solenoid valve 62, and reversing the second four-way valve 321, the machine room is operated in the heating mode to increase the temperature of the machine room and meet the requirements of constant temperature and humidity.

[0037] 3) Office heating and computer room heating modes. Figure 2CAs shown, the two first solenoid valves 61 are closed, the two second solenoid valves 62 are opened, and the first four-way valve 31 and the two second four-way valves 321 are switched. At this time, a part of the refrigerant in the system flows through the outdoor heat exchanger 11, the first four-way valve 31, the first compressor 41, the two first indoor heat exchangers 211 and the two first expansion valves 51 in sequence, and then returns to the outdoor heat exchanger 11, completing the heating cycle of the office; another part of the refrigerant in the system flows through the outdoor heat exchanger 11, the first four-way valve 31, the two second four-way valves 321, the two second compressors 421, the two second indoor heat exchangers 221 and the two second expansion valves 52 in sequence, and then returns to the outdoor heat exchanger 11, completing the heating cycle of the machine room. For example, in winter, when both the office and the machine room need to be heated, the air conditioning system operates in the above working mode, and adjusts the office temperature and the machine room temperature by adjusting the opening of the first expansion valve 51, and / or the opening of the second expansion valve 52, and / or the start and stop of the first compressor 41.

[0038] 4) Office heating and computer room cooling mode. Figure 2D As shown, the two first solenoid valves 61 are opened, the two second solenoid valves 62 are closed, the first four-way valve 31 is switched, and the two second four-way valves 321 remain in the initial state. At this time, a part of the refrigerant in the system flows through the outdoor heat exchanger 11, the first four-way valve 31, the first compressor 41, the two first indoor heat exchangers 211 and the two first expansion valves 51 in sequence, and then returns to the outdoor heat exchanger 11, completing the heating cycle of the office; another part of the refrigerant in the system flows through the two second indoor heat exchangers 221, the two second four-way valves 321, the two second compressors 421, the first four-way valve 31, the two first indoor heat exchangers 211, the two first expansion valves 51 and the two second expansion valves 52 in sequence, and then returns to the second indoor heat exchanger 221, completing the refrigeration cycle of the computer room. For example, in winter, both the office and the computer room are in heating mode (i.e. Figure 2C The working mode shown in the figure), but the temperature of the computer room is higher than the set temperature. At this time, by opening the first solenoid valve 61, closing the second solenoid valve 62, and reversing the second four-way valve 321, the computer room is operated in the cooling mode to reduce the temperature of the computer room and meet the requirements of constant temperature and humidity.

[0039] As can be seen from the above description, the multi-connected air conditioning system of the present invention can realize three circulation loops, namely: an office cooling / heating circulation loop consisting of an outdoor heat exchanger 11, a first expansion valve 51, a first indoor heat exchanger 211, a first four-way valve 31 and a first compressor 41; a machine room cooling / heating circulation loop consisting of an outdoor heat exchanger 11, a second expansion valve 52, a second indoor heat exchanger 221, a second four-way valve 321 and a second compressor 421; and a machine room cooling / heating circulation loop consisting of a first indoor heat exchanger 211, a first expansion valve 51, a second indoor heat exchanger 221, a second expansion valve 52, a first four-way valve 31, a second four-way valve 321 and a second compressor 421. That is, in addition to realizing the sharing and separate control of the outdoor units of the office indoor unit and the machine room indoor unit, the present invention can also realize the recovery of heat and cold in the machine room, and use it for heating or cooling the office, realizing efficient use of energy and reducing operating costs.

[0040] Finally, it should be noted that although the preferred embodiment is described in conjunction with the application scenarios of offices and computer rooms, this is not intended to limit the scope of protection of the present invention. Without departing from the principles of the present invention, those skilled in the art can also apply the present invention to other application scenarios, such as application scenarios of a combination of living rooms and computer rooms, supermarket halls and cold storage rooms, etc.

[0041] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A multi-connected air conditioning system, characterized in that: The multi-connected air conditioning system includes an outdoor heat exchanger, a first indoor heat exchanger group for cooling or heating indoor spaces other than the machine room, a second indoor heat exchanger group for cooling or heating the machine room, a first four-way valve, a first compressor, a second four-way valve group, and a second compressor group. Wherein, the first indoor heat exchanger group includes at least one first indoor heat exchanger, the second indoor heat exchanger group includes at least one second indoor heat exchanger, the second four-way valve group includes the same number of second four-way valves as the second indoor heat exchangers, and the second compressor group includes the same number of second compressors as the second four-way valves; Wherein, the first end of each of the first indoor heat exchangers is connected to the first end of the outdoor heat exchanger, and the second end of each of the first indoor heat exchangers is connected to the second end of the outdoor heat exchanger through the first four-way valve and the first compressor; wherein the first end of each of the second indoor heat exchangers is connected to the first end of the outdoor heat exchanger, and the second end of each of the second indoor heat exchangers is connected to the second end of the outdoor heat exchanger or the second end of the first indoor heat exchanger group through a second four-way valve and a second compressor; The second indoor heat exchanger group includes a plurality of second indoor heat exchangers, and the second compressor group and the second four-way valve group respectively include the same number of second compressors and second four-way valves as the second indoor heat exchangers; The multi-connected air-conditioning system also includes the same number of first solenoid valves and second solenoid valves as the second indoor heat exchangers, the first solenoid valve selectively connecting the exhaust side of the first compressor with the exhaust side of the second compressor, and the second solenoid valve selectively connecting the intake side of the first compressor with the intake side of the second compressor.

2. The multi-connected air conditioning system according to claim 1, characterized in that: The first indoor heat exchanger group includes a plurality of first indoor heat exchangers, and the plurality of first indoor heat exchangers are connected in parallel to each other.

3. The multi-connected air conditioning system according to claim 2, characterized in that: A first expansion valve is further provided between the outdoor heat exchanger and each of the first indoor heat exchangers.

4. The multi-connected air conditioning system according to claim 3, characterized in that: A second expansion valve is further provided between the outdoor heat exchanger and each of the second indoor heat exchangers.

5. The multi-connected air conditioning system according to claim 4, characterized in that: The outdoor heat exchanger, the first four-way valve and the first compressor are arranged in the outdoor unit of the multi-split air-conditioning system, each of the first indoor heat exchangers is arranged in the first indoor unit of the multi-split air-conditioning system, and each of the second indoor heat exchanger, the second four-way valve and the second compressor is arranged in the second indoor unit of the multi-split air-conditioning system.

6. The multi-connected air conditioning system according to claim 5, characterized in that: The first indoor unit is also provided with a first controller and a first temperature sensor, and the first controller is used to control the opening of the first expansion valve according to the indoor temperature detected by the first temperature sensor; and / or adjust the direction of the first four-way valve; and / or control the start and stop of the first compressor.

7. The multi-connected air conditioning system according to claim 5, characterized in that: The second indoor unit is also provided with a second controller and a second temperature sensor, and the second controller is used to adjust the opening of the second expansion valve according to the room temperature detected by the second temperature sensor; and / or adjust the direction of the second four-way valve; and / or control the start and stop of the second compressor.

8. The multi-connected air conditioning system according to claim 7, characterized in that: The second controller is further used to control the opening and closing of the first solenoid valve and / or the second solenoid valve.

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