Air conditioning system

Abstract

The invention provides an air conditioning system. The air conditioning system comprises an outdoor unit provided with an outdoor heat exchanger and a compressor, a liquid leading-out pipe from the outdoor unit, a heat recovery pipe, a high-low pressure air pipe and a low pressure air pipe. The first indoor unit is provided with a first shell, and the first indoor unit is connected with the outdoor unit through a liquid pipe and a heat recovery pipe; the second indoor unit is provided with a second shell, and the second indoor unit can be connected with the outdoor unit through a liquid pipe and a high-low-pressure air pipe or connected with the outdoor unit through the liquid pipe, the high-low-pressure air pipe and a low-pressure air pipe; a first indoor heat exchanger disposed in the first housing; a second indoor heat exchanger disposed in the second housing, the first and second indoor heat exchangers being fluidly connected on the liquid pipe side; the second indoor heat exchanger can work as an evaporator or a condenser, and the first indoor heat exchanger and the outdoor heat exchanger can work as the condenser or the evaporator at the same time. According to the air conditioning system, heat energy can be recycled, and the overall energy utilization rate of the air conditioning system is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of air conditioning technology, and in particular to an air conditioning system. BACKGROUND

[0002] In a multi-split air conditioning system, there is one outdoor unit and multiple indoor units connected, and the indoor units can be used for cooling or heating as needed. The design of this system allows some indoor units to provide cold air (cooling) and some indoor units to provide warm air (heating) at the same time, thereby meeting the different temperature requirements of the room.

[0003] From the principle point of view, this multi-split air conditioning system realizes the above functions through a complex piping system and valve control. Specifically, low-pressure gas pipes, high-low pressure gas pipes and liquid pipes are used in the outdoor unit and indoor unit of the air conditioning system. By adjusting the valves arranged in the pipeline, the flow direction and flow rate of the refrigerant are controlled, thereby determining whether each indoor unit is used for cooling or heating. In some models, a cold-heat switching device is also provided to realize waste heat recovery. The cold-heat switching device is a combination of multiple valves, which has a complex structure. Moreover, when using the cold-heat switching device to realize waste heat recovery, the user needs to turn on the cooling / heating indoor unit separately, which is complex for the user to operate. SUMMARY

[0004] The present application designs and provides an air conditioning system, specifically a four-pipe multi-scene convertible heat exchanger heat recovery system. The air conditioning system includes an outdoor unit, a first indoor unit and a second indoor unit.

[0005] In one or more embodiments of the present application, the outdoor unit includes an outdoor heat exchanger and a compressor, and a liquid pipe, a heat recovery pipe, a high-low pressure gas pipe and a low pressure gas pipe are led from the outdoor unit.

[0006] In one or more embodiments of the present application, the first indoor unit has a first housing, and the first indoor unit is connected to the outdoor unit via the liquid pipe and the heat recovery pipe.

[0007] In one or more embodiments of the present application, the second indoor unit has a second housing, and the second indoor unit can be connected to the outdoor unit via the liquid pipe and the high-low pressure gas pipe, or connected to the outdoor unit via the liquid pipe, the high-low pressure gas pipe and the low pressure gas pipe.

[0008] In one or more embodiments of the present application, the first indoor heat exchanger is arranged in the first housing.

[0009] In one or more embodiments of the present application, the second indoor heat exchanger is arranged in the second housing, and the first indoor heat exchanger and the second indoor heat exchanger are fluidly connected on the liquid pipe side.

[0010] In one or more embodiments of the present application, the second indoor heat exchanger can work as an evaporator or a condenser respectively, and the first indoor heat exchanger and the outdoor heat exchanger can work as a condenser simultaneously or as an evaporator simultaneously.

[0011] In one or more embodiments of the present application, the air conditioning system further comprises an operation terminal, which is arranged in matching with the second indoor unit and is used at least for receiving a mode selection instruction output by a user; when a heating mode instruction is received, the second indoor heat exchanger works as a condenser, and the first indoor heat exchanger and the outdoor heat exchanger work as an evaporator simultaneously; when a cooling mode instruction is received, the second indoor heat exchanger works as an evaporator, and the first indoor heat exchanger and the outdoor heat exchanger work as a condenser simultaneously.

[0012] In one or more embodiments of the present application, the first housing is arranged in a first space, and the first indoor heat exchanger can exchange heat with a medium in the first space.

[0013] In one or more embodiments of the present application, the second housing is arranged in a second space, and the first space and the second space are arranged independently, and the second indoor heat exchanger can exchange heat with a medium in the second space.

[0014] In one or more embodiments of the present application, the first housing is arranged in a first space, and the first housing has a first return air inlet and a first supply air outlet, and the first housing is arranged with a first indoor fan, and the first supply air outlet is communicated with an external space.

[0015] In one or more embodiments of the present application, the second housing is arranged in a second space, and the second indoor heat exchanger can exchange heat with a medium in the second space.

[0016] In one or more embodiments of the present application, the first return air inlet is in fluid communication with the second space, and return air of the second space enters the first housing from the first return air inlet and is discharged to an external space after exchanging heat with the first indoor heat exchanger.

[0017] In one or more embodiments of the present application, the air conditioning system further comprises a first indoor throttling element, which is arranged on a side of the first indoor heat exchanger connected with a liquid pipe.

[0018] In one or more embodiments of the present application, the air conditioning system further comprises a second indoor throttling element, which is arranged on a side of the second indoor heat exchanger connected with the liquid pipe.

[0019] In one or more embodiments of the present application, the air conditioning system further comprises a third indoor heat exchanger, which is arranged in the second housing, and the first indoor heat exchanger, the second indoor heat exchanger and the third indoor heat exchanger are in fluid connection on the side of the liquid pipe.

[0020] In one or more embodiments of the present application, the second indoor heat exchanger can work as an evaporator or a condenser respectively, and the third indoor heat exchanger can work as an evaporator, and the first indoor heat exchanger and the outdoor heat exchanger can work as a condenser or an evaporator simultaneously.

[0021] In one or more embodiments of the present application, the operation terminal is configured to receive a mode selection instruction output by a user, and when a heating mode instruction is received, the second indoor unit is configured to make the second indoor heat exchanger work as a condenser only, and the first indoor heat exchanger and the outdoor heat exchanger work as evaporators simultaneously; when a cooling mode instruction is received, the second indoor unit is configured to make the second indoor heat exchanger work as an evaporator only, or make the second indoor heat exchanger and the third indoor heat exchanger work as evaporators simultaneously, and the first indoor heat exchanger and the outdoor heat exchanger work as condensers simultaneously; when a dehumidification instruction is received, the second indoor unit is configured to make the second indoor heat exchanger work as a condenser, make the third indoor heat exchanger work as an evaporator, and make the first indoor heat exchanger and the outdoor heat exchanger work as evaporators or condensers simultaneously.

[0022] In one or more embodiments of the present application, the air conditioning system further comprises a third indoor throttling element arranged on a side of the third indoor heat exchanger connected with the liquid pipe.

[0023] In one or more embodiments of the present application, the air conditioning system further comprises a first switching valve, a first port of the first switching valve is connected with a discharge end of the compressor, a second port of the first switching valve is connected with a third port of the first switching valve through an electromagnetic valve and a capillary tube, the third port of the first switching valve is connected with a suction end of the compressor, and a fourth port of the first switching valve is connected with a high-low pressure gas pipe.

[0024] In one or more embodiments of the present application, the air conditioning system further comprises a second switching valve, a first port of the second switching valve is connected with a discharge end of the compressor, a second port of the second switching valve is connected with a third port of the second switching valve through an electromagnetic valve and a capillary tube, the third port of the second switching valve is connected with a suction end of the compressor, and a fourth port of the second switching valve is connected with the outdoor heat exchanger and the heat recovery pipe.

[0025] The air conditioning system provided by the present application has significant advantages in heat recovery and energy efficiency. The heat energy is recovered and utilized through the heat recovery pipe and the first indoor unit, thereby improving the overall energy utilization rate of the air conditioning system. The first indoor unit and the second indoor unit are linked and controlled. On the one hand, the user demand can be finely adjusted, and on the other hand, the operation is more friendly and simple. Through the optimized design of the refrigeration cycle, high-energy-efficiency operation is realized, and the cold and warm efficiency and the heat transfer efficiency of the system are improved.

[0026] Other features and advantages of the present application will become more apparent after reading the specific embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0028] Figure 1 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0029] Figure 2 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0030] Figure 3 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0031] Figure 4 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0032] Figure 5 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0033] Figure 6 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0034] Figure 7 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0035] Figure 8 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0036] Figure 9 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0037] Figure 10 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0038] Figure 11 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0039] Figure 12 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0040] Figure 13is a flowchart of an air conditioning system provided by one or more embodiments of the present application;

[0041] Fig. 10, outdoor unit;

[0042] 101-1, first compressor; 101-2, second compressor;

[0043] 102-1, first high-pressure switch; 102-2, second high-pressure switch;

[0044] 103-1, first oil separator; 103-2, second oil separator;

[0045] 104-1, first check valve; 104-2, second check valve;

[0046] 105-1, first capillary tube; 105-2, second capillary tube;

[0047] 106-1, first switching valve; A1, first switching valve first port; B1, first switching valve second port; C1, first switching valve third port; D1, first switching valve fourth port;

[0048] 106-2, second switching valve; A2, first switching valve first port; B2, first switching valve second port; C2, first switching valve third port; D2, first switching valve fourth port;

[0049] 107-1, first outdoor heat exchanger; 107-2, second outdoor heat exchanger;

[0050] 108-1, first outdoor throttling element; 108-2, second outdoor throttling element;

[0051] 109, third outdoor throttling element;

[0052] 110, subcooler;

[0053] 111, fourth outdoor throttling element;

[0054] 112, liquid accumulator;

[0055] 201, first indoor unit; 201-1, first indoor heat exchanger; 201-2, first indoor throttling element;

[0056] 202, second indoor unit; 202-1, second indoor heat exchanger; 202-2, second indoor throttling element;

[0057] 203-1, third indoor heat exchanger; 203-2, third indoor throttling element;

[0058] 204, first housing; 205, second housing;

[0059] 30, liquid pipe; 31, liquid pipe stop valve;

[0060] 40, heat recovery pipe; 41, heat recovery pipe stop valve;

[0061] 50, high-low pressure gas pipe; 51, high-low pressure gas pipe stop valve;

[0062] 60, low pressure gas pipe; 61, low pressure gas pipe stop valve;

[0063] 70, control terminal; 80, programmable logic controller;

[0064] 90, controller. DETAILED DESCRIPTION

[0065] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0066] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0067] The terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, "a plurality of" means two or more.

[0068] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through an intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0069] In the present application, unless otherwise explicitly specified and limited, "on" or "under" of a first feature to a second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "over" of a first feature to a second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the first feature is higher in horizontal height than the second feature. "Under", "below" and "underneath" of a first feature to a second feature includes that the first feature is directly below and obliquely below the second feature, or only means that the first feature is lower in horizontal height than the second feature.

[0070] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplification, the components and arrangements of specific examples are described in the following. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to reference numerals and reference letters in different examples, and such repetition is for the purpose of simplification and clarity, which does not indicate the relationship between the various embodiments and arrangements discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and the use of other materials.

[0071] In the following, one or more embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0072] Figure 1 is a structural schematic diagram of an air conditioning system provided according to one or more embodiments of the present application.

[0073] The air conditioning system provided in the present application can be applied to public spaces, such as office buildings, museums, hospitals, factories, etc., thereby realizing the processing and adjustment of air in the building. The air conditioning system provided in the present application is specifically a four-pipe multi-scene convertible heat exchanger heat recovery system.

[0074] With reference to Figure 1 and Figure 2 , the air conditioning system provided in the present application includes an outdoor unit 10, a first indoor unit 201 and a second indoor unit 202.

[0075] The first indoor unit 201 and the second indoor unit 202 can both be in cooling operation or heating operation.

[0076] The second indoor unit 202 can perform cooling, heating or dehumidification processing on air, and supply the processed air into an air conditioning room.

[0077] The first indoor unit 201 and the second indoor unit 202 can also exchange heat with other media (such as water) to perform cooling or heating.

[0078] The following description refers to the accompanying drawings Figure 1 and Figure 2 The outdoor unit 10 is introduced.

[0079] Referring to Figure 1 and Figure 2 The outdoor unit 10 includes an outdoor heat exchanger and a compressor, and four pipes are led out from the outdoor unit 10, i.e., a liquid pipe 30, a heat recovery pipe 40, a high-low pressure gas pipe 50, and a low pressure gas pipe 60. More specifically, a refrigerant circulation pipe is formed in the outdoor unit 10, which includes a first compressor 101-1, a second compressor 101-2, a first oil separator 103-1, and a second oil separator 103-2.

[0080] The first compressor 101-1 and the second compressor 101-2 have a hermetic structure with an internal motor; low-temperature and low-pressure refrigerant enters the first compressor 101-1 and the second compressor 101-2, respectively, and the first compressor 101-1 and the second compressor 101-2 compress the refrigerant gas into a high-temperature and high-pressure state and discharge the compressed refrigerant gas. Refrigeration oil is provided in the first compressor 101-1 and the second compressor 101-2, which is used to reduce the friction and wear of the first compressor 101-1 and the second compressor 101-2, to ensure the normal operation of the first compressor 101-1 and the second compressor 101-2. Two or more than two compressors connected in parallel or in groups can also be included in the outdoor unit 10, and more compressors can be provided. The actual operation frequency of each compressor can be allocated according to the cumulative running time of each compressor and the preset rotation order.

[0081] A first high-pressure switch 102-1 is provided at the discharge end of the first compressor 101-1, and a second high-pressure switch 102-2 is provided at the discharge end of the second compressor 101-2. The first high-pressure switch 102-1 and the second high-pressure switch 102-2 are used to monitor the pressure in the system. When the pressure in the system exceeds a certain threshold value, the first high-pressure switch 102-1 and / or the second high-pressure switch 102-2 will automatically cut off the power supply and stop the operation of the first compressor 101-1 and / or the second compressor 101-2, to protect the components in the system from damage caused by high pressure. The threshold value of the first high-pressure switch 102-1 and / or the second high-pressure switch 102-2 can be set according to the design parameters and working conditions of the air conditioning system. Once the pressure in the system is reduced to a safe level, the first high-pressure switch 102-1 and / or the second high-pressure switch 102-2 will restore the power supply to restart the first compressor 101-1 and / or the second compressor 101-2.

[0082] The discharge end of the first compressor 101-1 is provided with a first oil separator 103-1, and the discharge end of the second compressor 101-2 is provided with a second oil separator 103-2. The first oil separator 103-1 and the second oil separator 103-2 are used to separate the refrigerant from the refrigerant oil. Specifically, the first oil separator 103-1 and the second oil separator 103-2 separate the refrigerant oil from the refrigerant by the principle of physical separation (such as centrifugal force or gravity). The separated refrigerant oil is recycled and reused, and the refrigerant continues to flow.

[0083] A first one-way valve 104-1 is arranged downstream of the first oil separator 103-1, and a second one-way valve 104-2 is arranged downstream of the second oil separator 103-2, so as to avoid backflow of the refrigerant.

[0084] A first capillary tube 105-1 is arranged in conjunction with the first oil separator 103-1, and a second capillary tube 105-2 is arranged in conjunction with the second oil separator 103-2. The first capillary tube 105-1 is connected between the first compressor 101-1 and the first oil separator 103-1, and the second capillary tube 105-2 is connected between the second compressor 101-2 and the second oil separator 103-2. The first capillary tube 105-1 and the second capillary tube 105-2 recycle and guide the deposited refrigerant oil into the lubrication system of the first compressor 101-1 and the second compressor 101-2 by the principle of adsorption and guidance, so as to realize the recycling of the refrigerant oil.

[0085] The first oil separator 103-1 and the second oil separator 103-2 can be connected in series with a filter, respectively.

[0086] The second switching valve 106-2 (preferably a four-way valve) receives the refrigerant discharged from the first compressor 101-1 and the second compressor 101-2 through the first oil separator 103-1 and the second oil separator 103-2.

[0087] The second switching valve 106-2 has a second switching valve first port A2, a second switching valve second port B2, a second switching valve third port C2, and a second switching valve fourth port D2; one way of the second switching valve first port A2 is connected to the first oil separator 103-1 and the second oil separator 103-2, and the other way is connected to the first switching valve 106-1; the second switching valve second port B2 is connected to the second switching valve third port C2 through an electromagnetic valve and a capillary tube; the second switching valve third port C2 is connected to the suction end of the first compressor 101-1 and the second compressor 101-2; one way of the second switching valve fourth port D2 is connected to the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2, and the other way is connected to the heat recovery pipe 40.

[0088] The first switching valve 106-1 (also preferably realized by a four-way valve) has a first switching valve first port A1, a first switching valve second port B1, a first switching valve third port C1 and a first switching valve fourth port D1; the first switching valve first port A1 is connected to the first oil separator 103-1 and the second oil separator 103-2 in one way and connected to the second switching valve first port A1 in another way; the first switching valve second port B1 is connected to the first switching valve third port C1 through an electromagnetic valve and a capillary; the first switching valve third port C1 is connected to the suction end of the first compressor 101-1 and the second compressor 101-2; the first switching valve fourth port D1 is connected to the high-low pressure gas pipe 50.

[0089] The first switching valve 106-1 and the second switching valve 106-2 can have two states of ON and OFF. When in the state of ON, the flow path between the first switching valve first port A1 and the first switching valve second port B1 is conducted, the flow path between the first switching valve third port C1 and the first switching valve fourth port D1 is conducted, similarly, the flow path between the second switching valve first port A2 and the second switching valve second port B2 is conducted, the flow path between the second switching valve third port C2 and the second switching valve fourth port D2 is conducted; when in the state of OFF, the flow path between the first switching valve first port A1 and the first switching valve fourth port D1 is conducted, the flow path between the first switching valve second port B1 and the first switching valve third port C1 is conducted; similarly, the flow path between the second switching valve first port A2 and the second switching valve fourth port D2 is conducted, the flow path between the second switching valve second port B2 and the second switching valve third port C2 is conducted.

[0090] The outdoor unit 10 is provided with multiple outdoor heat exchangers arranged in parallel, exemplarily including a first outdoor heat exchanger 107-1 and a second outdoor heat exchanger 107-2. The first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 are connected to the second switching valve fourth port D2 in a parallel manner.

[0091] The first outdoor heat exchanger 107-1 is matched with a first outdoor throttling element 108-1, and the second outdoor heat exchanger 107-2 is matched with a second outdoor throttling element 108-2. The first indoor throttling element 201-2 is arranged on the side of the first indoor heat exchanger 201-1 connected to the liquid pipe 30, and the second indoor throttling element 202-2 is arranged on the side of the second indoor heat exchanger 202-1 connected to the liquid pipe 30.

[0092] The supercooler 110 is connected with the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2. The supercooler 110 is a heat exchanger, the refrigerant flowing to the liquid pipe 30 through the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2 is bypassed by the supercooler 110, and then flows into the supercooler 110 again through the fourth outdoor throttling element 111, so that the refrigerant flowing to the liquid pipe 30 is cooled. The fourth outdoor throttling element 111 can be an electronic expansion valve. The bypassed refrigerant can return to the suction end of the first compressor 101-1 and the second compressor 101-2, for example, return to the liquid accumulator 112 of the suction end of the first compressor 101-1 and the second compressor 101-2, and the liquid accumulator 112 is connected with the first compressor 101-1 and the second compressor 101-2 respectively.

[0093] In one or more embodiments of the present application, the outdoor unit 10 is further provided with a first outdoor fan (not shown) and a second outdoor fan (not shown), the start-stop and rotation speed of the first outdoor fan and the second outdoor fan can be independently controlled, and the air flow of the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 is changed by adjusting the rotation speed. The first outdoor fan can be an axial fan, a cross-flow fan or other optional fan forms, the first outdoor fan is arranged near the first outdoor heat exchanger 107-1, and the second outdoor fan is arranged near the second outdoor heat exchanger 107-2.

[0094] Referring to the drawings Figure 1 and Figure 2 The indoor unit is introduced.

[0095] In one or more embodiments of the present application, the first indoor unit 201 has a first shell 204, and the first indoor heat exchanger 201-1 is arranged in the first shell 204. The first shell 204 is provided with a first return air inlet and a first air outlet, and the first air outlet can send the air heated by the first indoor heat exchanger 201-1 into the room or discharge to the external space.

[0096] The first indoor heat exchanger 201-1 is connected with the outdoor unit 10 through the heat recovery pipe 40 (exemplarily, it can be a C-shaped pipe) and the liquid pipe 30 respectively.

[0097] The first indoor heat exchanger 201-1 is matched with the first indoor throttling element 201-2.

[0098] The first indoor unit 201 is further provided with a first indoor fan (not shown), and the first indoor fan can be an axial fan or a cross-flow fan.

[0099] The first indoor heat exchanger 201-1 can also exchange heat with other medium, for example, water.

[0100] In one or more embodiments of the present application, the second indoor unit 202 has a second housing 205, and a second indoor heat exchanger 202-1 is arranged in the second housing 205. The second housing 205 is provided with a second return air inlet and a second supply air outlet, and the second supply air outlet can send air after heat exchange with the second indoor heat exchanger 202-1 into the indoor.

[0101] The second indoor heat exchanger 202-1 is connected to the outdoor unit 10 through high and low pressure gas pipes 50 and liquid pipes 30, respectively.

[0102] The second indoor heat exchanger 202-1 is matched with a second indoor throttling element 202-2.

[0103] The second indoor unit 202 is further provided with a second indoor fan (not shown), which can be an axial fan or a cross-flow fan.

[0104] In one or more embodiments of the present application, the first housing 204 is arranged in a first space, and the first indoor heat exchanger 201-1 can exchange heat with the medium in the first space.

[0105] The second housing 205 is arranged in a second space, and the first space and the second space are independently arranged, and the second indoor heat exchanger 202-1 can exchange heat with the medium in the second space.

[0106] In one or more embodiments of the present application, the first housing 204 is arranged in a first space, and the first supply air outlet is communicated with the external space.

[0107] In one or more embodiments of the present application, the air sent into the indoor for heat exchange through the second supply air outlet can be further introduced into the first housing 204 through the first return air inlet, and after heat exchange with the first indoor heat exchanger 201-1, it is discharged to the outdoor.

[0108] The controller 90 is arranged in a housing with good sealing performance and heat dissipation function. The controller 90 includes components such as a processor, a storage unit, an input / output interface, and a communication interface. The processor can be a dedicated processor, a central processing unit (CPU), etc. The processor can access the storage unit to execute instructions or applications stored in the storage unit to implement related functions, such as the frequency of the compressor operation driven by the program. The storage unit can include volatile memory and / or non-volatile memory. The input / output interface can be connected to the various sensors mentioned above to receive the detection values ​​of the various sensors. The input / output interface is also connected to the first compressor 101-1, the second compressor 101-2 and other devices to output the control instructions generated by the processor. The communication interface can support different wireless communication protocols, such as Wi-Fi, Bluetooth, near-field communication, NB-IoT, etc., to communicate with other electronic devices, including but not limited to cloud servers, programmable logic controllers 9080, computers (host computers), smart phones, tablet computers, PDAs, intelligent control tools, wearable devices and vehicle-mounted devices, etc.

[0109] In one or more embodiments of the present application, only the second indoor unit 202 is equipped with a control terminal 70, and the first indoor unit 201 is not equipped with a control terminal 70. The control terminal 70 is used to control the air conditioning system, including start-stop control, temperature setting, air volume setting, receiving user-entered mode selection instructions, mode switching, and other functions. The control terminal 70 is fixedly installed indoors and is equipped with a touch screen or buttons and a display screen for displaying system operating status and alarm information. The control terminal 70 can also be a remote controller 90, including but not limited to an infrared remote control, a smart phone, and an intelligent control terminal.

[0110] When receiving a heating mode instruction, the second indoor heat exchanger 202-1 works as a condenser, and the first indoor heat exchanger 201-1 and the outdoor heat exchanger work as evaporators at the same time; when receiving a cooling mode instruction, the second indoor heat exchanger 202-1 works as an evaporator, and the first indoor heat exchanger 201-1 and the outdoor heat exchanger work as condensers at the same time.

[0111] like Figure 3 and Figure 4 As shown, the user selects the cooling mode through the control terminal 70. At this time, there are two different situations according to different installation areas of the first indoor unit 201. For example, air is used as the target medium.

[0112] In the first case, the first indoor unit 201 and the second indoor unit 202 are installed in different indoor spaces. The second indoor heat exchanger 202-1 works as an evaporator, and the first indoor heat exchanger 201-1 and the outdoor heat exchanger work as condensers at the same time.

[0113] From the principle, low temperature and low pressure refrigerant into the first compressor 101-1 and the second compressor 101-2, the first compressor 101-1 and the second compressor 101-2 are compressed into high temperature and high pressure state of refrigerant gas and discharge the compressed refrigerant gas. At this time, the first switch valve 106-1 is in the ON state, the second switch valve 106-2 is in the OFF state, the discharged refrigerant gas flows into the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 through the second switch valve first port A2, the second switch valve fourth port D2, the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 work in the condenser state, the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 condense the compressed refrigerant into liquid phase, and the heat is released to the surrounding environment through the condensation process. The high temperature and high pressure state of liquid phase refrigerant formed in the condenser flows through the subcooler 110 into the liquid pipe 30, and enters the second indoor unit 202, in this process, the first outdoor throttling element 108-1, the second outdoor throttling element 108-2 and the second indoor throttling element 202-2 expand the high temperature and high pressure state of liquid phase refrigerant formed in the condenser into low pressure liquid phase refrigerant.

[0114] The refrigerant passing through the second switch valve first port A2, the second switch valve fourth port D2 also enters the first indoor unit 201 through the heat recovery pipe 40, that is, enters the first indoor heat exchanger 201-1, the first indoor heat exchanger 201-1 works in the condenser state, the first indoor heat exchanger 201-1 condenses the compressed refrigerant into liquid phase, and the heat is released to the surrounding environment through the condensation process, and the first indoor unit 201 realizes heating. The high temperature and high pressure state of liquid phase refrigerant formed in the first indoor heat exchanger 201-1 flows through the first indoor throttling element 201-2, the first indoor throttling element 201-2 expands the high temperature and high pressure state of liquid phase refrigerant formed in the first indoor heat exchanger 201-1 into low pressure liquid phase refrigerant.

[0115] The expanded low pressure liquid phase refrigerant converges and enters the second indoor heat exchanger 202-1. The second indoor heat exchanger 202-1 works in the evaporator state, the second indoor heat exchanger 202-1 evaporates the refrigerant expanded in the first outdoor throttling element 108-1, the second outdoor throttling element 108-2, the second indoor throttling element 202-2 and the first indoor throttling element 201-2, and makes the refrigerant in low temperature and low pressure state return to the first compressor 101-1 and the second compressor 101-2 through the high and low pressure gas pipe 50, the first switch valve fourth port D1, the first switch valve third port D3 and the liquid accumulator 112. The second indoor heat exchanger 202-1 can exchange heat with the material to be cooled to realize the refrigeration effect.

[0116] In this case, the heat originally dissipated to the environment by the outdoor unit 10 in the cooling mode is partly recovered, and the first indoor unit 201 uses this part of the heat for heating, improving the overall efficiency of the air conditioning system.

[0117] In the second case, the air sent into the room (second space) by the second air outlet for heat exchange is further introduced into the first shell 204 through the first return air outlet, and is discharged to the outside after heat exchange with the first indoor heat exchanger 201-1. The air temperature of the air sent into the room for heat exchange through the second air outlet is relatively low, and compared with the outdoor heat exchanger in a high temperature and working in a condensing state, the condensing effect and capacity of the first heat exchanger as a condenser are obviously improved, from an overall point of view, so that the air conditioning system can consume less energy to achieve the same effect, thereby realizing effective heat recovery.

[0118] The first indoor fan and the second indoor fan are controlled in linkage, that is, when the second indoor fan is on standby or stopped, the first indoor fan also stops running.

[0119] The user selects the heating mode through the control terminal 70, at this time, according to different installation areas of the first indoor unit 201, there are two different cases.

[0120] In the first case, the first indoor unit 201 and the second indoor unit 202 are installed in different indoor spaces. The second indoor heat exchanger 202-1 works as a condenser, and the first indoor heat exchanger 201-1 and the outdoor heat exchanger work as evaporators at the same time.

[0121] From the principle point of view, the low-temperature and low-pressure refrigerant enters the first compressor 101-1 and the second compressor 101-2, and the first compressor 101-1 and the second compressor 101-2 compress the refrigerant gas into high-temperature and high-pressure state and discharge the compressed refrigerant gas. At this time, the first switching valve 106-1 is in the OFF state, and the second switching valve 106-2 is in the ON state, and the discharged refrigerant gas passes through the first switching valve first port A1, the first switching valve fourth port D1 into the high-low pressure gas pipe 50, and then enters the second indoor unit 202, flows into the second indoor heat exchanger 202-1, and the second indoor heat exchanger 202-1 works in the condenser state. The second indoor heat exchanger 202-1 condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensing process.

[0122] The high-temperature and high-pressure liquid-phase refrigerant formed in the condenser is condensed and returned to the outdoor unit 10 side through the liquid pipe 30. In this process, the second indoor throttling element 202-2, the first outdoor throttling element 108-1, and the second outdoor throttling element 108-2 expand the high-temperature and high-pressure liquid-phase refrigerant formed in the condenser into low-pressure liquid-phase refrigerant. The first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 operate in an evaporator state, evaporate the refrigerant expanded in the second indoor throttling element 202-2, the first outdoor throttling element 108-1, and the second outdoor throttling element 108-2, and return the refrigerant in a low-temperature and low-pressure state to the first compressor 101-1 and the second compressor 101-2 through the second switching valve fourth port D2 and the second switching valve third port C2 and the accumulator 112.

[0123] The high-temperature and high-pressure liquid-phase refrigerant formed in the condenser flows into the first indoor unit 201. In this process, the first indoor throttling element 201-2 expands the high-temperature and high-pressure liquid-phase refrigerant formed in the condenser into low-pressure liquid-phase refrigerant. The first indoor heat exchanger 201-1 operates in an evaporator state, evaporates the refrigerant expanded in the first indoor throttling element 201-2, and returns the refrigerant in a low-temperature and low-pressure state to the first compressor 101-1 and the second compressor 101-2 through the second switching valve fourth port D2 and the second switching valve third port C2 and the accumulator 112.

[0124] In this case, the heat originally emitted to the environment by the outdoor unit 10 in the heating mode is partially recovered, and the first indoor unit 201 uses this part of the heat for refrigeration, improving the overall efficiency of the air conditioning system.

[0125] In the second case, the air that has been sent into the room through the first air supply port and has been heat-exchanged is further introduced into the second housing 205 through the second return air port and is discharged to the outside after being heat-exchanged with the second indoor heat exchanger 202-1. The temperature of the air that has been sent into the room through the first air supply port and has been heat-exchanged is relatively high, thereby improving the evaporation effect and capacity of the first heat exchanger as an evaporator, allowing the air conditioning system to consume less energy to achieve the same effect, thereby achieving efficient heat recovery.

[0126] The cooperation of the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2 can enable the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 to achieve refrigerant storage, refrigerant release, and refrigerant locking, and variable storage of refrigerant, so that the refrigerant in the air conditioning system is always at an appropriate level.

[0127] In the above process, the first indoor unit 201 and the second indoor unit 202 are controlled in a unified linkage by the control terminal 70, without the participation of a cooling and heating switching device, and the user operation is simple and user-friendly.

[0128] In the above embodiment, the low-pressure gas pipe 60 is kept shut off and not used. The liquid pipe 30 is provided with a liquid pipe shutoff valve 31. The high- and low-pressure gas pipes 50 are provided with high- and low-pressure gas pipe shutoff valves 61. The heat recovery pipe 40 is provided with a heat recovery pipe shutoff valve 41.

[0129] Only one second indoor unit 202 is shown in the figure. Using the same connection method, more first indoor units 201 and second indoor units 202 can be configured. There is no limit to the number of first indoor units 201 and second indoor units 202.

[0130] In one or more embodiments of the present application, a third outdoor throttling element 109 is provided between at least one of the multiple outdoor heat exchangers arranged in parallel and the fourth port of the first switching valve; exemplarily, a third outdoor throttling element 109 is provided between the second outdoor heat exchanger 107-2 and the fourth port D2 of the first switching valve.

[0131] In the heating-primary mode, the second outdoor heat exchanger 107-2 can control refrigerant storage, refrigerant release, and refrigerant lock, respectively, through the second outdoor throttle element 108-2 and the third outdoor throttle element 109. The second outdoor heat exchanger 107-2 can store refrigerant at a variable level, ensuring that the refrigerant level in the air conditioning system is always at an appropriate level. The heating-primary mode refers to when the heating load exceeds the cooling load, and the outdoor unit 10 operates in heating mode. Specifically, the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 operate in the evaporator state.

[0132] like Figure 5 and Figure 13 As shown, the controller 90 performs the following steps:

[0133] The opening degree of the second outdoor throttling element 108 - 2 is controlled according to the superheat, and the third outdoor throttling element 109 is kept fully open.

[0134] Push the real-time status of customized heat load rate.

[0135] If the heating load rate is lower than the set lower limit threshold, it is further estimated whether the real-time operating conditions meet the refrigerant storage conditions. For example, it is estimated whether the compressor exhaust pressure, the compressor operating frequency, and the temperature difference between the compressor exhaust temperature and the saturation temperature corresponding to the compressor exhaust pressure meet the refrigerant storage conditions. If the refrigerant storage conditions are met, the second outdoor throttling element 108-2 is controlled to be fully open, and the third outdoor throttling element 109 is controlled to be fully closed, and the excess refrigerant is stored through the second outdoor heat exchanger 107-2.

[0136] If the heating load rate is higher than the set upper limit threshold, it is further estimated whether the real-time operating conditions meet the refrigerant release conditions. For example, it is estimated whether the compressor exhaust pressure, the compressor operating frequency, and the temperature difference between the compressor exhaust temperature and the saturation temperature corresponding to the compressor exhaust pressure meet the refrigerant release conditions. If the refrigerant release conditions are met, the second outdoor throttling element 108-2 is controlled to be fully closed, the third outdoor throttling element 109 is controlled to be fully closed, and the third outdoor throttling element 109 is controlled to perform a gradual valve opening operation from the fully closed state to allow the second outdoor heat exchanger to release the refrigerant.

[0137] During the valve opening process, if the refrigerant release condition is no longer satisfied, the current valve opening of the third outdoor throttling element 109 is kept unchanged.

[0138] During the valve opening process, it is estimated whether the third outdoor throttling element 109 has reached the maximum opening. If the third outdoor throttling element 109 has reached the maximum opening, the opening of the second outdoor throttling element 108-2 is controlled according to the superheat, and the third outdoor throttling element 109 is kept fully open to release excess refrigerant through the second outdoor heat exchanger 107-2.

[0139] If the heating load rate is between the set lower limit threshold and the set upper limit threshold, it is further estimated whether the real-time operating conditions meet the refrigerant locking conditions. For example, it is estimated whether the compressor exhaust pressure, the compressor operating frequency, and the temperature difference between the compressor exhaust temperature and the saturation temperature corresponding to the compressor exhaust pressure meet the refrigerant locking conditions. If the refrigerant locking conditions are met, the second outdoor throttling element 108-2 is controlled to be fully closed, and the third outdoor throttling element 109 is controlled to be fully closed, and the excess refrigerant is locked through the second outdoor heat exchanger 107-2.

[0140] If the air conditioner is not operating in the heating main operation mode, the second outdoor throttling element 108 - 2 and the third outdoor throttling element 109 are both controlled to be in a fully open state.

[0141] like Figure 6 and Figure 7 As shown, in one or more embodiments of the present application, a second indoor heat exchanger 202-1 and a third indoor heat exchanger 203-1 are disposed in the second housing 205. The third indoor heat exchanger 203-1 is connected to the outdoor unit 10 via the low-pressure gas pipe 60 and the liquid pipe 30, respectively. The first indoor heat exchanger 201-1, the second indoor heat exchanger 202-1, and the third indoor heat exchanger 203-1 are fluidically connected on the liquid pipe 30 side. The third indoor heat exchanger 203-1 can operate in an evaporator state, thereby having the following multiple operating modes, such as Figure 8 to Figure 11 shown.

[0142] In the first mode of operation, the user selects the cooling mode (full load) via the control terminal 70.

[0143] In the first mode of operation, the low temperature and low pressure refrigerant enters the first compressor 101-1 and the second compressor 101-2. The first compressor 101-1 and the second compressor 101-2 compress the refrigerant gas into a high temperature and high pressure state and discharge the compressed refrigerant gas. At this time, the first switching valve 106-1 is in the ON state and the second switching valve 106-2 is in the OFF state. The discharged refrigerant gas flows into the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 via the second switching valve first port A2 and the second switching valve second port D2. The first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 operate in the condenser state. The first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 condense the compressed refrigerant into a liquid phase and release heat to the surrounding environment through the condensation process. The high temperature and high pressure state liquid phase refrigerant formed in the condenser flows into the liquid pipe 30 via the subcooler 110. In this process, the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2 expand the high temperature and high pressure state liquid phase refrigerant formed in the condenser into a low pressure liquid phase refrigerant.

[0144] The refrigerant passing through the second switching valve first port A2 and the second switching valve fourth port D2 also enters the first indoor heat exchanger 201-1 via the heat recovery pipe 40. The first indoor heat exchanger 201-1 operates in the condenser state. The first indoor heat exchanger 201-1 condenses the compressed refrigerant into a liquid phase and releases heat to the surrounding environment through the condensation process. The first indoor unit 201 achieves heating. The high temperature and high pressure state liquid phase refrigerant formed in the first indoor heat exchanger 201-1 flows through the first indoor throttling element 201-2.

[0145] After passing through the second indoor throttling element 202-2 and the third indoor throttling element 203-2, respectively, the expanded low pressure liquid phase refrigerant enters the second indoor heat exchanger 202-1 and the third indoor heat exchanger 203-1, respectively. The second indoor heat exchanger 202-1 and the third indoor heat exchanger 203-1 operate in the evaporator state and evaporate the expanded refrigerant. The second indoor heat exchanger 202-1 causes the refrigerant in the low temperature and low pressure state to return to the first compressor 101-1 and the second compressor 101-2 via the high and low pressure gas pipe 50, the first switching valve fourth port D1, the first switching valve third port D3, and the liquid accumulator 112. The third indoor heat exchanger 203-1 causes the refrigerant in the low temperature and low pressure state to return to the first compressor 101-1 and the second compressor 101-2 via the liquid accumulator 112.

[0146] The first working mode can improve the refrigeration capacity of the air conditioning system, i.e. to provide a full load working mode.

[0147] The second working mode, the user selects the refrigeration mode (partial load) through the control terminal 70, the refrigerant flow path of the third heat exchanger is cut off, the third heat exchanger stops running, and the working mode of the second heat exchanger is the same as that in the refrigeration mode in the first embodiment, which will not be described here.

[0148] The third working mode, the user selects the heating mode through the control terminal 70, the refrigerant flow path of the third heat exchanger is cut off, the third heat exchanger stops running, and the working mode of the second heat exchanger is the same as that in the heating mode in the first embodiment, which will not be described here.

[0149] The fourth working mode, the user selects the non-cooling dehumidification mode through the control terminal 70.

[0150] From the principle point of view, in the fourth working mode, the low-temperature and low-pressure refrigerant enters the first compressor 101-1 and the second compressor 101-2, and the first compressor 101-1 and the second compressor 101-2 compress the refrigerant gas into a high-temperature and high-pressure state and discharge the compressed refrigerant gas. At this time, the first switching valve 106-1 is in the OFF state, and the second switching valve 106-2 is in the ON state, and the discharged refrigerant gas enters the high-low pressure gas pipe 50 through the first switching valve first port A1 and the first switching valve fourth port D1, and then flows into the second indoor heat exchanger 202-1, and the second indoor heat exchanger 202-1 works in the condenser state. The second indoor heat exchanger 202-1 condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0151] The high-temperature and high-pressure state liquid phase refrigerant formed in the condenser returns to the outdoor unit 10 side through the liquid pipe 30. In this process, the second indoor throttling element 202-2, the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2 expand the high-temperature and high-pressure state liquid phase refrigerant formed in the condenser into low-pressure liquid phase refrigerant. The first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 work in the evaporator state, the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 evaporate the refrigerant expanded in the second indoor throttling element 202-2, the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2, and make the refrigerant in a low-temperature and low-pressure state return to the first compressor 101-1 and the second compressor 101-2 through the second switching valve fourth port D2 and the second switching valve third port C2, and the liquid accumulator 112.

[0152] The high-temperature and high-pressure liquid-phase refrigerant formed in the condenser flows into the third indoor heat exchanger 203-1. In this process, the third indoor throttling element 203-2 expands the high-temperature and high-pressure liquid-phase refrigerant formed in the condenser into low-pressure liquid-phase refrigerant. The third indoor heat exchanger 203-1 works in an evaporator state, evaporates the refrigerant expanded in the third indoor throttling element 203-2, and returns the refrigerant in a low-temperature and low-pressure state to the first compressor 101-1 and the second compressor 101-2 through the low-pressure gas pipe 60 and the liquid accumulator 112. The third indoor heat exchanger 203-1 can exchange heat with the material to be cooled to achieve a dehumidification effect, at this time, the second indoor heat exchanger 202-1 is in a heating state, and the second indoor unit 202 achieves non-cooling dehumidification.

[0153] The high-temperature and high-pressure liquid-phase refrigerant formed in the condenser flows into the first indoor unit 201. In this process, the first indoor throttling element 201-2 expands the high-temperature and high-pressure liquid-phase refrigerant formed in the condenser into low-pressure liquid-phase refrigerant. The first indoor heat exchanger 201-1 works in an evaporator state, evaporates the refrigerant expanded in the first indoor throttling element 201-2, and returns the refrigerant in a low-temperature and low-pressure state to the first compressor 101-1 and the second compressor 101-2 through the second switching valve fourth port D2 and the second switching valve third port C2 and the liquid accumulator 112.

[0154] On the basis of the fourth working mode, in the fifth working mode, the work of the third indoor heat exchanger 203-1 can be stopped alone, and only the heating operation of the second indoor heat exchanger 202-1 is retained, in this case, the working states of the first switching valve 106-1 and the second switching valve 106-2 remain unchanged, and the first indoor unit 201 cools.

[0155] In the sixth working mode, the user selects the non-cooling dehumidification mode through the control terminal 70.

[0156] From the principle point of view, the sixth working mode, low temperature and low pressure refrigerant enters the first compressor 101-1 and the second compressor 101-2, the first compressor 101-1 and the second compressor 101-2 compress the refrigerant gas into high temperature and high pressure state and discharge the compressed refrigerant gas. At this time, the first switching valve 106-1 is in the OFF state, the second switching valve 106-2 is in the OFF state, the discharged refrigerant gas flows into the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 through the second switching valve first port A2, the second switching valve second port D2, the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 work in the condenser state, the first outdoor heat exchanger 107-1 and the second outdoor heat exchanger 107-2 condense the compressed refrigerant into liquid phase, and heat is released to the surrounding environment through the condensation process. The high temperature and high pressure state liquid phase refrigerant formed in the condenser flows through the subcooler 110 into the liquid pipe 30. In this process, the first outdoor throttling element 108-1 and the second outdoor throttling element 108-2 expand the high temperature and high pressure state liquid phase refrigerant formed in the condenser into low pressure liquid phase refrigerant.

[0157] The refrigerant passing through the second switching valve first port A2 and the second switching valve fourth port D2 also enters the first indoor heat exchanger 201-1 through the heat recovery pipe 40, the first indoor heat exchanger 201-1 works in the condenser state, the first indoor heat exchanger 201-1 condenses the compressed refrigerant into liquid phase, and heat is released to the surrounding environment through the condensation process, and the first indoor unit 201 realizes heating. The high temperature and high pressure state liquid phase refrigerant formed in the first indoor heat exchanger 201-1 flows through the first indoor throttling element 201-2.

[0158] The refrigerant gas discharged by the compressor passes through the first switching valve first port A1, the first switching valve fourth port D1, and the high and low pressure gas pipe 50 into the second indoor heat exchanger 202-1, the second indoor heat exchanger 202-1 works in the condenser state, the second indoor heat exchanger 202-1 condenses the compressed refrigerant into liquid phase, and heat is released to the surrounding environment through the condensation process, and the high temperature and high pressure state liquid phase refrigerant formed in the second indoor heat exchanger 202-1 flows through the third indoor throttling element 203-2.

[0159] After passing through the first indoor throttling element 201-2 and the third indoor throttling element 203-2 respectively, the expanded low pressure liquid phase refrigerant further enters the third indoor heat exchanger 203-1. The third indoor heat exchanger 203-1 works in the evaporator state, and evaporates the expanded refrigerant. The third indoor heat exchanger 203-1 makes the refrigerant in low temperature and low pressure state return to the first compressor 101-1 and the second compressor 101-2 through the low pressure gas pipe 60 and the liquid accumulator 112.

[0160] On the basis of the sixth working mode, the seventh working mode can stop the operation of the second indoor heat exchanger 202-1 alone, and only keep the third indoor heat exchanger 203-1 refrigerating (dehumidifying) operation, in which case the working states of the first switching valve 106-1 and the second switching valve 106-2 remain unchanged, and the first indoor unit 201 heats.

[0161] Only one second indoor unit 202 is shown in the figure, and the same connection mode can be adopted for more first indoor units 201 and second indoor units 202, and the number of the first indoor units 201 and the second indoor units 202 is not limited.

[0162] In the heating main operation mode, the second outdoor heat exchanger 107-2 can realize corresponding control of refrigerant storage, refrigerant release and refrigerant locking through the second outdoor throttling element 108-2 and the third outdoor throttling element 109, and the second outdoor heat exchanger 107-2 can variably store refrigerant, so that the refrigerant in the air conditioning system is always at an appropriate level. The heating main operation mode refers to a case where the heating load is greater than the cooling load, and the outdoor unit 10 operates in the heating operation mode.

[0163] The heating load rate refers to the ratio of the capacity of the indoor unit in the heating state to the total capacity.

[0164] As shown in Figure 12 and Figure 13 , the controller 90 performs the following steps:

[0165] The opening degree of the second outdoor throttling element 108-2 is controlled according to the superheat degree, and the third outdoor throttling element 109 is kept fully open.

[0166] The real-time state of the heating load rate is estimated.

[0167] If the heating load rate is lower than the set lower threshold, it is further estimated whether the real-time working condition meets the refrigerant storage condition, and exemplarily, it is estimated whether the compressor discharge pressure, the compressor operating frequency, and the temperature difference between the compressor discharge temperature and the corresponding saturated temperature of the compressor discharge pressure meet the refrigerant storage condition. If the refrigerant storage condition is met, the second outdoor throttling element 108-2 is fully opened, the third outdoor throttling element 109 is fully closed, and the excess refrigerant is stored through the second outdoor heat exchanger 107-2.

[0168] If the heating load ratio is higher than the set upper threshold, it is further determined whether the real-time working condition meets the refrigerant releasing condition, for example, it is determined whether the compressor discharge pressure, the compressor operating frequency, and the temperature difference between the compressor discharge temperature and the saturation temperature corresponding to the compressor discharge pressure meet the refrigerant releasing condition, and if the refrigerant releasing condition is met, the second outdoor throttling element 108-2 is controlled to be fully closed, the third outdoor throttling element is controlled to be fully closed, and the third outdoor throttling element 109 is controlled to perform gradual valve opening operation from the fully closed state, so that the second outdoor heat exchanger releases the refrigerant.

[0169] During the valve opening process, if the refrigerant releasing condition is no longer met, the current valve opening degree of the third outdoor throttling element 109 is kept unchanged.

[0170] During the valve opening process, it is determined whether the third outdoor throttling element 109 reaches the maximum opening degree, and if the third outdoor throttling element 109 reaches the maximum opening degree, the opening degree of the second outdoor throttling element 108-2 is controlled according to the superheat degree, the third outdoor throttling element 109 is kept fully open, and the second outdoor heat exchanger 107-2 releases the excess refrigerant.

[0171] If the heating load ratio is between the set lower threshold and the set upper threshold, it is further determined whether the real-time working condition meets the refrigerant locking condition, for example, it is determined whether the compressor discharge pressure, the compressor operating frequency, and the temperature difference between the compressor discharge temperature and the saturation temperature corresponding to the compressor discharge pressure meet the refrigerant locking condition, and if the refrigerant locking condition is met, the second outdoor throttling element 108-2 is controlled to be fully closed, the third outdoor throttling element 109 is controlled to be fully closed, and the second outdoor heat exchanger 107-2 locks the excess refrigerant.

[0172] If the heating main body operating mode is not used, the second outdoor throttling element 108-2 and the third outdoor throttling element 109 are both controlled to be in the fully open state.

[0173] In one or more embodiments of the present application, the refrigerant storage condition includes that the compressor discharge pressure is higher than a first corrected target pressure maximum value, the actual compressor operating frequency is lower than a first set compressor frequency threshold, and the temperature difference between the compressor discharge temperature and the saturation temperature corresponding to the compressor discharge pressure is lower than a first set temperature difference threshold; wherein: the target pressure maximum value is generated based on the temperature difference between the set temperature of the heating indoor unit and the return air temperature, and the greater the temperature difference between the set temperature and the return air temperature, the greater the target pressure maximum value; and the first corrected target pressure maximum value is the sum of the target pressure maximum value and a correction value.

[0174] The first set compressor frequency threshold is generated based on the calculated compressor frequency. The calculated compressor frequency is the compressor operating frequency calculated based on the current starting load and the corresponding indoor demand condition according to an empirical formula.

[0175] For example, the compressor frequency can be calculated by the following empirical formula:

[0176] F C (n) = A x [∑ i (C on (i) x K c (i)) ] + B x KT x [∑ j (H on (j) x K h (j)) ] + {C x [∑ k (HTh off (k)) ] + D x [∑ 1n (H off (m))} ] x Khp

[0177] In the above formula, C on (i) is the total operating capacity (HP) of the i-th cooling Thermo ON indoor unit, H on (j) is the total operating capacity of the j-th heating Thermo ON indoor unit; HTh off (k) is the total capacity of the k-th heating Thermo OFF indoor unit, in HP; H off (m) is the total capacity of the m-th heating stop indoor unit, in HP, where A, B, C, and D are constants.

[0178] Khp is the discharge pressure correction coefficient, when P d ≥ P do , then Khp = E - (P dmax - P do ) x F, where 0.1 ≤ Khp ≤ 1; otherwise Khp = 1.

[0179] KT is the outdoor environment temperature correction coefficient, KT = G x T a + H, where G and H are constants.

[0180] K c (i) and K h (j) are the i-th indoor unit temperature difference capacity correction coefficients, K c (i) and K h (j) are generated based on the difference between the return air temperature and the set temperature, the greater the absolute value of the difference between the return air temperature and the set temperature, the greater K c (i) and K h (j) are.

[0181] The first set compressor frequency threshold is a product of a calculated compressor frequency and a first proportional coefficient, the first proportional coefficient being a constant obtained under experimental conditions and stored in a constant form for ready call, and the first proportional coefficient can be set to be less than 1.

[0182] The first set temperature difference threshold is a constant, and the first set temperature difference threshold is preset and stored.

[0183] In one or more embodiments of the present application, the refrigerant release condition comprises: the compressor discharge pressure is lower than a second corrected target pressure maximum value, the actual compressor operating frequency is higher than a second set compressor frequency threshold, and the temperature difference between the compressor discharge temperature and the saturation temperature corresponding to the compressor discharge pressure is higher than a second set temperature difference threshold; wherein: the target pressure maximum value is generated based on the temperature difference between the set temperature of the heating indoor unit and the return air temperature, and the greater the temperature difference between the set temperature and the return air temperature, the greater the target pressure maximum value; the second corrected target pressure maximum value is the difference between the target pressure maximum value and a correction value.

[0184] The set compressor frequency threshold is generated based on a calculated compressor frequency. The calculated compressor frequency is a compressor operating frequency calculated based on an empirical formula according to the current starting load and the corresponding indoor demand condition.

[0185] The calculated compressor frequency can adopt the calculation formula as shown above, which will not be described here.

[0186] The second set compressor frequency threshold is a product of the calculated compressor frequency and a second proportional coefficient, the second proportional coefficient being a constant obtained under experimental conditions and stored in a constant form for ready call, and the second proportional coefficient can be set to be greater than 1.

[0187] The second set temperature difference threshold is a constant, and the second set temperature difference threshold is preset and stored. The second set temperature difference threshold is higher than the first set temperature difference threshold.

[0188] When neither the refrigerant storage condition nor the refrigerant release condition is satisfied, it is determined that the refrigerant locking condition is satisfied.

[0189] In the present application, the throttling element can be an electronic expansion valve.

[0190] In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0191] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. Air conditioning system, characterized in that, include: The outdoor unit comprises an outdoor heat exchanger and a compressor, a liquid pipe, a heat recovery pipe, high- and low-pressure gas pipes, and a low-pressure gas pipe leading out of the outdoor unit; a first indoor unit having a first housing, the first indoor unit being connected to the outdoor unit via a liquid pipe and a heat recovery pipe; a second indoor unit having a second housing, wherein the second indoor unit can be connected to the outdoor unit via a liquid pipe and high- and low-pressure gas pipes, or connected to the outdoor unit via a liquid pipe, high- and low-pressure gas pipes, and a low-pressure gas pipe; a first indoor heat exchanger disposed in the first housing; and a second indoor heat exchanger disposed in the second housing, the first indoor heat exchanger and the second indoor heat exchanger being fluidly connected on a liquid pipe side; The second indoor heat exchanger can work as an evaporator or a condenser respectively, and the first indoor heat exchanger and the outdoor heat exchanger can work as a condenser or as an evaporator at the same time.

2. The air conditioning system according to claim 1, characterized in that Also includes: an operation terminal, the operation terminal being matched with the second indoor unit and being at least configured to receive a mode selection instruction input by a user; When receiving a heating mode instruction, the second indoor heat exchanger works as a condenser, and the first indoor heat exchanger and the outdoor heat exchanger work as evaporators at the same time; when receiving a cooling mode instruction, the second indoor heat exchanger works as an evaporator, and the first indoor heat exchanger and the outdoor heat exchanger work as condensers at the same time.

3. The air conditioning system according to claim 1, characterized in that The first shell is disposed in the first space, and the first indoor heat exchanger can exchange heat with the medium in the first space; The second shell is disposed in a second space, the first space and the second space are independently disposed, and the second indoor heat exchanger can exchange heat with a medium in the second space.

4. The air conditioning system according to claim 1, characterized in that The first shell is arranged in the first space, the first shell has a first return air port and a first air supply port, a first indoor fan is arranged in the first shell, and the first air supply port is connected to the external space; The second shell is disposed in the second space, and the second indoor heat exchanger can exchange heat with the medium in the second space; The first return air port is in fluid communication with the second space. Return air from the second space enters the first shell from the first return air port, exchanges heat with the first indoor heat exchanger, and is discharged to the external space.

5. The air conditioning system according to claim 1, characterized in that Also includes: A first indoor throttling element is disposed on a side where the first indoor heat exchanger is connected to the liquid pipe.

6. The air conditioning system according to claim 1, characterized in that Also includes: The second indoor throttling element is arranged on a side where the second indoor heat exchanger is connected to the liquid pipe.

7. The air conditioning system according to claim 1, characterized in that Also includes: a third indoor heat exchanger disposed in the second housing, wherein the first indoor heat exchanger, the second indoor heat exchanger, and the third indoor heat exchanger are fluidically connected on a liquid pipe side; The second indoor heat exchanger can work as an evaporator or a condenser respectively, the third indoor heat exchanger can work as an evaporator, and the first indoor heat exchanger and the outdoor heat exchanger can work as a condenser or an evaporator at the same time.

8. The air conditioning system according to claim 7, characterized in that Also includes: An operation terminal is matched with the second indoor unit, and the operation terminal is at least used to receive a mode selection instruction output by the user; when receiving a heating mode instruction, the second indoor unit is configured to make only the second indoor heat exchanger work as a condenser, and the first indoor heat exchanger and the outdoor heat exchanger work as evaporators at the same time; when receiving a cooling mode instruction, the second indoor unit can be configured to make only the second indoor heat exchanger work as an evaporator, or make the second indoor heat exchanger and the third indoor heat exchanger work as evaporators at the same time, and the first indoor heat exchanger and the outdoor heat exchanger work as condensers at the same time; when receiving a dehumidification instruction, the second indoor unit can be configured to make the second indoor heat exchanger work as a condenser, make the third indoor heat exchanger work as an evaporator, and the first indoor heat exchanger and the outdoor heat exchanger work as evaporators or condensers at the same time.

9. The air conditioning system according to claim 8, characterized in that Also includes: A third indoor throttling element is arranged on a side where the third indoor heat exchanger is connected to the liquid pipe.

10. The air conditioning system according to any one of claims 1 to 9, characterized in that: Also includes: a first switching valve, wherein the first port of the first switching valve is connected to the discharge end of the compressor, the second port of the first switching valve is connected to the third port of the first switching valve through a solenoid valve and a capillary tube, the third port of the first switching valve is connected to the suction end of the compressor, and the fourth port of the first switching valve is connected to the high and low pressure air pipes; and The second switching valve, the first port of the second switching valve is connected to the exhaust end of the compressor, the second port of the second switching valve is connected to the third port of the second switching valve through the solenoid valve and the capillary tube, the third port of the second switching valve is connected to the suction end of the compressor, and the fourth port of the second switching valve is connected to the outdoor heat exchanger and the heat recovery pipe.

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