CN213362914U - Multi-split system - Google Patents

Abstract

The present disclosure relates to a multi-split system, including: an outdoor unit; each indoor unit comprises an indoor unit heat exchanger, an indoor unit side air pipe and an indoor unit side liquid pipe, wherein the indoor unit side air pipe and the indoor unit side liquid pipe are connected to two sides of the indoor unit heat exchanger; and a mode conversion device including: the first outdoor unit side pipe and the second outdoor unit side pipe are both connected with the outdoor unit; a first throttling part and a second throttling part; the inlet of the first gas-liquid separator is communicated with one end of the second outer machine side pipe; the liquid outlet of the first gas-liquid separator is connected with a liquid outlet pipe, one end of the liquid outlet pipe is divided into a first branch and a second branch after passing through the first throttling component, the first branch is connected with the indoor unit side liquid pipes of the indoor units, and the second branch is communicated with the first outdoor unit side liquid pipes after passing through the second throttling component.

Description

Multi-split system

Technical Field

The disclosure relates to the technical field of air conditioners, in particular to a multi-split system.

Background

In order to meet the requirements of users, the air conditioner can adopt a multi-split system, wherein the multi-split system means that different indoor units can simultaneously run a refrigerating or heating mode in one set of system so as to meet the individual requirements of different users, and the multi-split system is widely suitable for air conditioning of commercial places and office environments, and is particularly suitable for use environments with large load changes.

At present, the outdoor side of a multi-split air-conditioning system mainly adopts three pipes and complex pipelines, but the system is simplified increasingly along with the improvement of the technical level of air-conditioning, and the two pipe-conditioning systems gradually enter main flow. Therefore, how to realize that the two-pipe multi-split air conditioner system simultaneously conveys the refrigerants in different states to the corresponding refrigerating indoor unit and the heating indoor unit still remains a problem to be solved at present.

SUMMERY OF THE UTILITY MODEL

The embodiment of the disclosure provides a multi-split air conditioning system, which can simply realize refrigerant distribution of the multi-split air conditioning system.

According to an aspect of the present disclosure, there is provided a multi-split system including:

an outdoor unit;

each indoor unit comprises an indoor unit heat exchanger, an indoor unit side air pipe and an indoor unit side liquid pipe, wherein the indoor unit side air pipe and the indoor unit side liquid pipe are connected to two sides of the indoor unit heat exchanger; and

a mode switching apparatus comprising:

the first outdoor unit side pipe and the second outdoor unit side pipe are both connected with the outdoor unit;

a first throttling part and a second throttling part; and

the inlet of the first gas-liquid separator is communicated with one end of the second outer machine side pipe; the liquid outlet of the first gas-liquid separator is connected with a liquid outlet pipe, one end of the liquid outlet pipe is divided into a first branch and a second branch after passing through the first throttling component, the first branch is connected with the indoor unit side liquid pipes of the indoor units, and the second branch is communicated with the first outdoor unit side liquid pipes after passing through the second throttling component.

In some embodiments, the refrigerator further comprises a control device configured to open the first throttling part and close the second throttling part in the full cooling mode and the main body cooling mode; and/or in the complete heating mode, the main heating mode and the complete heat recovery mode, closing the first throttling component and opening the second throttling component.

In some embodiments, the mode conversion apparatus further comprises:

the first ends of the refrigeration branches are connected with the indoor unit side air pipes of the indoor units in a one-to-one correspondence mode, and each refrigeration branch is provided with a refrigeration on-off valve; and

the first ends of the heating branches are connected with the indoor unit side air pipes of the indoor units in a one-to-one correspondence mode, and each heating branch is provided with a heating on-off valve;

the air outlet of the first gas-liquid separator is connected with an air outlet pipe, one end of the air outlet pipe is communicated with the respective second ends of the plurality of heating branches, and the second branches are communicated with the first outer machine side pipe after being communicated with the respective second ends of the plurality of refrigerating branches.

In some embodiments, the control device is further configured to open the cooling on-off valve corresponding to the indoor unit in cooling operation and close the heating on-off valve, and open the heating on-off valve corresponding to the indoor unit in heating operation and close the cooling on-off valve.

In some embodiments, the indoor unit further includes a third throttling part provided on the inner machine side liquid pipe.

In some embodiments, the outdoor unit includes: the multi-split system also comprises a control device, and the control device is configured to determine the number of the outdoor unit heat exchangers participating in refrigerant circulation according to the heat exchange demand of the outdoor unit obtained by the refrigeration demand and the heating demand of the indoor units.

In some embodiments, the outdoor unit includes:

a compressor;

a four-way valve;

the outdoor unit liquid pipe is communicated with an evaporation side connecting pipe of the four-way valve;

the inlet of the second gas-liquid separator is communicated with a suction side pipe of the four-way valve, and the outlet of the second gas-liquid separator is communicated with a suction port of the compressor; and

and a first end of the heat recovery branch is communicated with the external liquid pipe, a second end of the heat recovery branch is communicated with an inlet of the second gas-liquid separator, a third cut-off valve is arranged on the heat recovery branch, and the third cut-off valve is configured to be switched on when the outdoor unit is in a complete heat recovery state.

In some embodiments, the outdoor unit further comprises:

a fourth and fifth on-off valve configured to communicate with the first and second outer machine side pipes through respective first ports, respectively; wherein the content of the first and second substances,

the outdoor air pipe comprises a first air pipe branch and a second air pipe branch, the first ends of the first air pipe branch and the second ends of the second air pipe branch are communicated, the second ends of the first air pipe branch and the second air pipe branch are respectively communicated with the second ports of the fourth on-off valve and the fifth on-off valve, the first air pipe branch is provided with a first one-way valve which only allows the refrigerant to flow towards the first end of the first air pipe branch, and the second air pipe branch is provided with a second one-way valve which only allows the refrigerant to flow towards the second end of the second air; and

the outer liquid pipe comprises a first liquid pipe branch and a second liquid pipe branch, respective first ends of the first liquid pipe branch and the second liquid pipe branch are communicated, respective second ends of the first liquid pipe branch and the second liquid pipe branch are communicated with respective second ports of a fifth on-off valve and a fourth on-off valve respectively, a third one-way valve which only allows the refrigerant to flow towards the second end of the first liquid pipe branch is arranged on the first liquid pipe branch, and a fourth one-way valve which only allows the refrigerant to flow towards the first end of the second liquid pipe branch is arranged on the second liquid pipe branch.

The multi-split system of the embodiment of the disclosure, through the design of the pipeline connection mode in the mode switching device, can directly control the flow direction of the refrigerant through the high-low pressure state of the refrigerant, so as to convey the refrigerant in different states to the corresponding refrigerating and heating indoor units, so as to realize the simultaneous refrigerating and heating operation of the indoor units, can save the two existing control systems to be provided with a plurality of check valves and realize the function by means of the mechanical action of the check valves, therefore, the system structure can be simplified, the pipeline consumables can be reduced, the refrigerant loss can be reduced, and the reliability of the system operation can be improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the disclosure and together with the description serve to explain the disclosure and not to limit the disclosure. In the drawings:

FIG. 1 is a schematic diagram of some embodiments of a multiple online system of the present disclosure;

FIG. 2 is a schematic view of some embodiments of the multi-split air conditioning system of the present disclosure in a full cooling mode;

FIG. 3 is a schematic view of some embodiments of a multiple on-line system of the present disclosure in a full heating mode;

FIG. 4 is a schematic view of some embodiments of the multiple on-line system of the present disclosure in a bulk cooling mode;

FIG. 5 is a schematic view of some embodiments of the multiple online system of the present disclosure in a body heating mode;

fig. 6 is a schematic diagram of some embodiments of the disclosed multi-split air conditioning system in a full heat recovery mode.

Detailed Description

The present disclosure is described in detail below. In the following paragraphs, different aspects of the embodiments are defined in more detail. Aspects so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature considered to be preferred or advantageous may be combined with one or more other features considered to be preferred or advantageous.

The terms "first", "second", and the like in the present disclosure are merely for convenience of description to distinguish different constituent elements having the same name, and do not denote a sequential or primary-secondary relationship.

In addition, when an element is referred to as being "on" another element, it can be directly on the other element or be indirectly on the other element with one or more intervening elements interposed therebetween. In addition, when an element is referred to as being "connected to" another element, it may be directly connected to the other element or may be indirectly connected to the other element with one or more intervening elements interposed therebetween. Hereinafter, like reference numerals denote like elements.

The description of the relative orientations and positional relationships of the indications "upper," "lower," "top," "bottom," "front," "back," "inner" and "outer" and the like are used in this disclosure for convenience in describing the disclosure, and do not indicate or imply that the indicated devices must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the scope of the disclosure.

As shown in fig. 1, the present disclosure provides a multi-split system, which is suitable for a two-pipe multi-split system having only one air pipe and one liquid pipe. In some embodiments, the multi-split air conditioning system includes an outdoor unit 1, a plurality of indoor units 5, and a mode switching device 3.

Wherein each of the plurality of indoor units 5 includes an indoor unit heat exchanger 51, and an indoor unit-side air duct 53 and an indoor unit-side liquid duct 54 connected to both sides of the indoor unit heat exchanger 51.

The mode conversion apparatus 3 includes: a first outdoor unit side pipe 32 and a second outdoor unit side pipe 33 both connected to the outdoor unit 1; the first throttling part 35(EXV1) and the second throttling part 37(EXV2), for example, an electronic expansion valve or a capillary tube can be used as the throttling part; a first gas-liquid separator 31, an inlet I of the first gas-liquid separator 31 communicating with one end of the second outer-unit-side pipe 33; an outlet O2 of the first gas-liquid separator 31 is connected to an outlet 38, one end of the outlet 38 passes through the first throttling part 35 and then is divided into a first branch 38A and a second branch 38B, the first branch 38A is connected to the indoor unit side liquid tubes 54 of the indoor units 5, and the second branch 38B passes through the second throttling part 37 and then is communicated with the first outdoor unit side tube 32. For example, the first gas-liquid separator 31 may be a flash evaporator or a gas-liquid separation by means of centrifugal force.

In the multi-split air-conditioning system of this embodiment, switching of the working modes of the multi-split air-conditioning system can be realized by on-off control of the first throttling component 35 and the second throttling component 37, the first throttling component 35 is configured to open the liquid refrigerant separated by the first gas-liquid separator 31 to the indoor unit heat exchanger 51 in the cooling operation when the refrigeration of the indoor units 5 is dominant, so as to perform evaporation heat exchange, and the second throttling component 37 is configured to open the liquid refrigerant condensed and heat exchanged by the indoor unit heat exchanger 51 to flow to the first outdoor unit side pipe 32 through the first branch pipe 38A and the second branch pipe 38B when the heating of the indoor units 5 is dominant, so as to return to the outdoor unit 1.

Furthermore, the mode switching device 3 can directly control the flowing direction of the refrigerant through the high-low pressure state of the refrigerant by acquiring the heating demand and the cooling demand of the plurality of indoor units 5, so as to convey the refrigerant in different states to the corresponding refrigerating indoor unit and the corresponding heating indoor unit through the refrigerant in different states flowing through the first gas-liquid separator 31, thereby realizing the simultaneous refrigerating and heating operation of the plurality of indoor units, omitting the arrangement of a plurality of check valves in the existing two-control system and realizing the function by means of the mechanical action of the check valves, thereby simplifying the system structure, reducing the material consumption of the pipeline, reducing the refrigerant loss and improving the reliability of the system operation.

In some embodiments, the multi-split system of the present disclosure further includes a control device configured to open the first throttling component 35 and close the second throttling component 37 in the complete cooling mode and the main cooling mode, so that the liquid refrigerant separated by the first gas-liquid separator 31 can only flow to the indoor unit side liquid pipe 54 of the indoor unit 5 for cooling operation through the first branch 38A, so as to be provided to the indoor unit heat exchanger 51 for cooling operation for evaporation heat exchange, and the low-temperature and low-pressure gaseous refrigerant after heat exchange enters the outdoor unit 1 through the first outdoor unit side pipe 32. And/or in the complete heating mode, the main heating mode and the complete heat recovery mode, the first throttling component 35 is closed, the second throttling component 37 is opened, the gaseous refrigerant separated from the air outlet pipe 39 of the first gas-liquid separator 31 enters the indoor unit heat exchanger 51 through the indoor unit side liquid pipe 53 of the indoor unit 5 in the heating operation for condensation and heat exchange, and the liquid refrigerant after heat exchange can only flow to the first outdoor unit side pipe 32 through the first branch pipe 38A and the second branch pipe 38B to return to the outdoor unit 1.

The embodiment can conveniently realize the switching of the multi-split system between different working modes, and is convenient to control.

In some embodiments, the mode conversion apparatus 3 further includes: a plurality of refrigeration branches 42, respective first ends of the plurality of refrigeration branches 42 are connected to respective indoor unit-side air tubes 53 of the plurality of indoor units 5 in a one-to-one correspondence manner, and each refrigeration branch 42 is provided with a refrigeration on-off valve 41, for example: SV5, SV6, SV7, SV 8; and a plurality of heating branches 40, wherein first ends of the plurality of heating branches 40 are connected to the indoor unit side air pipes 53 of the plurality of indoor units 5 in a one-to-one correspondence manner, and each heating branch 40 is provided with a heating on-off valve 43, for example, SV1, SV2, SV3, and SV 4.

An outlet pipe 39 is connected to an outlet of the first gas-liquid separator 31, one end of the outlet pipe 39 is communicated with the second ends of the plurality of heating branches 40, and the second branch 38B is communicated with the second ends of the plurality of cooling branches 42 and then communicated with the first outdoor unit-side pipe 32.

In some embodiments, the multi-split system further includes a control device configured to open the cooling on-off valve 41 corresponding to the indoor unit 5 in the cooling operation and close the heating on-off valve 43, and open the heating on-off valve 43 corresponding to the indoor unit 5 in the heating operation and close the cooling on-off valve 41.

In the embodiment, when the indoor units 5 which are in cooling and heating operation exist at the same time, the pipeline connection mode in the mode conversion device 3 can directly control the flowing direction of the refrigerant through the high-low pressure state of the refrigerant and the corresponding cooling on-off valve 41 and the heating on-off valve 43, so that the refrigerants in different states can be conveyed to the corresponding cooling and heating indoor units, a plurality of check valves arranged in the two existing control systems can be omitted, and the function can be realized by the mechanical action of the check valves, therefore, the structure of the heat recovery system can be simplified, the pipeline consumables can be reduced, and the reliability of the system in working can be improved.

In some embodiments, the indoor unit 5 further includes a third throttling component 52, where the third throttling component 52 is disposed on the indoor unit side liquid pipe 54, and is used for throttling and cooling the liquid refrigerant provided by the first branch line 38A, so as to facilitate subsequent evaporation heat exchange and improve the conversion rate of the gaseous refrigerant.

In some embodiments, the mode conversion apparatus 3 further includes: a first heat exchanger 36 disposed between the outlet pipe 38 and the second branch 38B, the first heat exchanger 36 having a first port 361 and a third port 363 communicating with each other and a second port 362 and a fourth port 364 communicating with each other. The first port 361 is connected to the first throttle member 35, the second port 362 is connected to the first outer unit side tube 32, the third port 363 is connected to the connection point between the first branch 38A and the second branch 38B, and the fourth port 364 is connected to the second throttle member 37. Wherein the first heat exchanger 36 may be a plate heat exchanger or a double pipe heat exchanger.

In this embodiment, by providing the first heat exchanger 36, the liquid refrigerant condensed by the indoor unit 5 in the heating operation can be subcooled by the liquid refrigerant in the liquid outlet pipe 38 in the process of returning to the first outdoor unit side pipe 32 through the second branch pipe 38B, so as to increase the cooling capacity.

Further, the mode conversion apparatus 3 further includes: and a second heat exchanger 34 disposed between the outlet pipe 38 and the second branch 38B, wherein the first plate heat exchanger 34 has a fifth port 341, a seventh port 343, a sixth port 342 and an eighth port 344, which are communicated with each other. The fifth port 341 communicates with the outlet port O2 of the first gas-liquid separator 31, the sixth port 342 communicates with the first outer-unit-side pipe 32, the seventh port 343 is connected to the first throttling member 35, and the eighth port 344 is connected to the second throttling member 37. Wherein the second heat exchanger 34 may be a plate heat exchanger or a double pipe heat exchanger.

In this embodiment, by providing the second heat exchanger 34, the liquid refrigerant condensed by the indoor unit 5 in the heating operation can be subcooled by the liquid refrigerant in the liquid outlet pipe 38 in the process of returning to the first outdoor unit side pipe 32 through the second branch pipe 38B, so as to increase the cooling capacity.

The first heat exchanger 36 and the second heat exchanger 34 may be disposed at either one of them or at the same time. When the first port 344 of the second heat exchanger 34 is connected to the second port 362 of the first heat exchanger 36, the liquid refrigerant condensed by the indoor unit 5 in the heating operation is subcooled by the second heat exchanger 34 and then further subcooled by the first heat exchanger 36 in the process of returning to the first outdoor unit side tube 32 through the second branch 38B, so that the subcooling effect is improved, and the cooling capacity is increased.

In some embodiments, the outdoor unit 1 includes: the multi-split system further comprises a control device, and the control device is configured to determine the number of the outdoor unit heat exchangers 10 participating in refrigerant circulation according to the cooling demand and the heating demand of the indoor units 5, which are obtained from the heat exchange demand of the outdoor unit 1. The outdoor unit 1 and the indoor units 5 may share a control device, or may be provided as separate control devices.

The heat exchange demand of the outdoor unit is (heating demand-cooling demand) absolute value/rated capacity of the outdoor unit.

Specifically, the control device may calculate the heating demand according to the total rated capacity of the indoor units 5 in the heating operation, and calculate the cooling demand according to the total rated capacity of the indoor units 5 in the cooling operation.

According to the embodiment, the plurality of outdoor unit heat exchangers 10 are arranged, so that the outdoor unit heat exchangers 10 participating in refrigerant circulation can be controlled according to the refrigeration demand and the heating demand of the plurality of indoor units 5 when the multi-split system is in different working modes, the heat exchange capacity of the outdoor unit heat exchangers 10 can be guaranteed to meet the working demand of the indoor units 5, the heat exchange capacity of the outdoor unit heat exchangers 10 can be saved, and more energy can be saved.

In some embodiments, as shown in fig. 1, the outdoor unit 1 further includes: four-way valve 19, compressor 21, outer liquid pipe 24 and outer trachea 23, four-way valve 19 has four connecting pipes, includes: an exhaust side adapter D, a condensation side adapter C, a suction side adapter S, and an evaporation side adapter E. The outer air pipe 23 communicates with the evaporation side connection pipe E of the four-way valve 19.

An outer machine side gas pipe and an outer machine side liquid pipe 15 are respectively arranged on two sides of each outer machine heat exchanger 10. The outdoor unit side air pipe comprises a third branch 11 and a fourth branch 13, the third branch 11 and the fourth branch 13 are respectively provided with a first on-off valve 12 and a second on-off valve 14, and the on-off valves mentioned in the embodiment of the disclosure can be electromagnetic valves and the like.

The respective first ends of the third branches 11 of the at least two outer machine heat exchangers 10 are respectively connected with the corresponding outer machine heat exchangers 10, and the respective second ends of the third branches 11 of the at least two outer machine heat exchangers 10 are converged and then communicated with a condensation side connecting pipe C of the four-way valve 19. The respective first ends of the fourth branches 13 of the at least two outer machine heat exchangers 10 are respectively connected to the third branch 11 of the outer machine heat exchanger 10, and the respective second ends are converged and then communicated with the outer machine air pipe 23, which is equivalent to being communicated with the evaporation side connecting pipe E of the four-way valve 19. The third branch 11 and the fourth branch 13 of the same outdoor unit heat exchanger 10 may be provided with a common gas pipe at a side close to the outdoor unit heat exchanger 10.

The outer machine side liquid pipes 15 are connected to the other side of the outer machine heat exchangers 10, respective first ends of the outer machine side liquid pipes 15 of at least two outer machine heat exchangers 10 are respectively connected with the corresponding outer machine heat exchangers 10, and respective second ends of the outer machine side liquid pipes 15 are converged and then communicated with the outer machine liquid pipe 24.

When the outdoor unit 1 is in the heating mode, and the control device is configured to turn off the third branch 11 by the first on-off valve 12 and turn on the fourth branch 13 by the second on-off valve 14 corresponding to each of the partial outdoor unit heat exchangers 10 when the outdoor unit 1 needs defrosting, so that the partial outdoor unit heat exchangers 10 are in a defrosting state; and the first on-off valve 12 corresponding to each of the rest of at least some outdoor unit heat exchangers 10 is connected to the third branch 11, and the second on-off valve 14 is disconnected from the second branch 12, so that the part of the outdoor unit heat exchangers 10 is in a heating state, and the rest of the outdoor unit heat exchangers 10 may be outdoor unit heat exchangers 10 which are defrosted completely or are not defrosted.

For example, the outdoor unit heat exchangers 10 in the defrosting state may be one or more, and the defrosting may be performed alternately. The number of the outdoor unit heat exchangers 10 in the defrosting state can be determined according to the total heating demand of the indoor unit, if the heat exchange demand of the outdoor unit is large, fewer outdoor unit heat exchangers 10 can be in the defrosting state at the same time, and the heat exchange demand of the system is ensured; if the heat exchange demand of the outdoor unit is small, more outdoor unit heat exchangers 10 are allowed to be in a defrosting state at the same time, so that the defrosting efficiency is improved.

For example, two outdoor unit heat exchangers 10 are provided, so that one of the outdoor unit heat exchangers 10 is defrosted first, the other outdoor unit heat exchanger 10 is defrosted after defrosting is finished, and the defrosted outdoor unit heat exchanger 10 is restored to a heating state.

According to the outdoor unit device of the embodiment, based on the two-pipe heat recovery system, when the outdoor unit 1 is in the heating mode and needs defrosting, part of the outdoor unit heat exchangers 10 are defrosted firstly, meanwhile, part of the outdoor unit heat exchangers 10 are still in the heating state, the problem that the two-pipe heating recovery multi-split air conditioner system needs to be shut down when heating defrosting is carried out is solved, the indoor unit can still have a certain heating effect, user experience is improved, and heating time can be shortened when the heat recovery mode is copied after the whole defrosting process is finished.

In some embodiments, the outer air tube 23 is connected to the evaporation side connection tube E of the four-way valve 19, and the respective first ends of the outer air tube side tubes 15 of at least two outer air heat exchangers 10 are respectively connected to the corresponding outer air heat exchangers 10, and the respective second ends are merged and then connected to the outer air tube side tube 24.

The outdoor unit 1 further includes: a second gas-liquid separator 20, an inlet of the second gas-liquid separator 20 is communicated with a suction side pipe S of the four-way valve 19, and an outlet of the second gas-liquid separator 20 is communicated with a suction port I of the compressor 21; and a heat recovery branch 17, a first end of the heat recovery branch 17 being in communication with the outdoor unit liquid pipe 24, a second end of the heat recovery branch 17 being in communication with an inlet of the second gas-liquid separator 20, the heat recovery branch 17 being provided with a third cut-off valve 18, the third cut-off valve 18 being configured to be turned on when the outdoor unit 1 is in a complete heat recovery state.

In some embodiments, as shown in fig. 1, the outdoor unit 1 further includes: the fourth and fifth on-off valves 26A and 26B are disposed so as to communicate with the first and second outer machine side pipes 32 and 33 through the respective first ports 341, respectively.

The outer air tube 23 includes a first air tube branch 23A and a second air tube branch 23B, respective first ends of which are communicated, respective second ends of which are respectively communicated with respective second ports 342 of the fourth on-off valve 26A and the fifth on-off valve 26B, the first air tube branch 23A is provided with a first check valve 25A which only allows the refrigerant to flow toward the first end of the first air tube branch 23A, and the second air tube branch 23B is provided with a second check valve 25B which only allows the refrigerant to flow toward the second end of the second air tube branch 23B.

The outer liquid pipe 24 includes a first liquid pipe branch 24A and a second liquid pipe branch 24B, respective first ends of which are communicated, respective second ends of which are respectively communicated with respective second ports 342 of a fifth cut-off valve 26B and a fourth cut-off valve 26A, a third check valve 25C that allows only the refrigerant to flow toward the second end of the first liquid pipe branch 24A is disposed on the first liquid pipe branch 24A, and a fourth check valve 25D that allows only the refrigerant to flow toward the first end of the second liquid pipe branch 24B is disposed on the second liquid pipe branch 24B.

In this embodiment, the heat recovery of the two-pipe multi-split air-fuel machine can be realized by adopting a branch pipeline arrangement for the external air pipe 23 and the external liquid pipe 24 and matching with a one-way valve.

Based on the above embodiment, the working modes of the multi-split system include: at least one of a full cooling mode, a main body cooling mode, a full heat recovery mode, a main body heating mode, and a full heating mode. The operation principle of the multi-split system in each mode will be described with reference to fig. 2 to 6. Solid arrows in the figure indicate liquid refrigerant, and dashed arrows indicate gaseous refrigerant.

1. A full cooling mode:

in the cooling mode, as shown in fig. 2, the four-way valve 19 of the outdoor unit 1 communicates the compressor discharge port with the third branch 11 of the plurality of outdoor unit heat exchangers 10; the first throttling part 35 is opened, the second throttling part 37 is closed, the cooling on-off valve 41 corresponding to the indoor unit 5 in the cooling operation is opened to switch on the cooling branch 42, and the heating on-off valve 43 is closed to switch off the heating branch 40 in the mode converter 3. The third shut-off valve 18 on the heat recovery branch 17 is opened.

As for the outdoor unit 1, as shown in fig. 2, at this time, the heat exchange requirement is large, the first on-off valve 12 in the two outdoor unit heat exchangers 10 is connected to the third branch 11, the second on-off valve 14 is disconnected from the fourth branch 13, the first throttling element 16 is opened, the third on-off valve 18 in the heat recovery branch 17 is disconnected, and at this time, both the two outdoor unit heat exchangers 10 participate in refrigerant circulation.

At this time, the exhaust gas of the compressor 21 sequentially passes through the two third branches 11 and enters the outer unit heat exchanger 10 for condensation heat exchange, and the condensed liquid refrigerant reaches the outer unit liquid pipe 24 through the outer unit side liquid pipe 15, and sequentially passes through the first liquid pipe branch 24A, the fifth on-off valve 26B and the second outer unit side pipe 33 and enters the inlet I of the first gas-liquid separator 31. After gas-liquid separation, liquid refrigerant passes through the second heat exchanger 34, the first throttling part 35 and the first heat exchanger 36 from the liquid outlet pipe 38 in sequence, then enters the indoor unit side liquid pipe 54 of the refrigerating operation indoor unit 5 from the second branch 38A, and then reaches the indoor unit heat exchanger 51 for evaporation heat exchange, low-temperature and low-pressure gaseous refrigerant formed after heat exchange passes through the inner unit side gas pipe 53 and the refrigerating branch 42 in sequence, then is converged to the first outer unit side pipe 32, and then passes through the fourth shut-off valve 26A, the first gas pipe branch 23A, the outer unit gas pipe 23 and the reversing valve 19 to enter the second gas-liquid separator 20, and the separated gaseous refrigerant enters the compressor 21 for compression to form high-temperature and high-pressure gaseous refrigerant.

2. Main body cooling mode

As shown in fig. 4, the first throttling part 35 is opened and the second throttling part 37 is closed in the mode converter 3. Compared with the full cooling mode, for the main cooling mode, there are both heating indoor units and cooling indoor units, and at this time, the heating on-off valve 43 corresponding to the heating indoor unit is opened to switch on the heating branch 40, and the cooling on-off valve 41 is closed to switch off the cooling branch 42.

The main cooling mode and the complete cooling mode have a similar refrigerant flow direction in the outdoor unit 1. The difference is that the gaseous refrigerant discharged from the air outlet pipe 39 of the first gas-liquid separator 31 enters the indoor unit heat exchanger 51 through the heating branch 40 of the heating operation indoor unit 5 (the uppermost indoor unit 5) and the indoor unit-side air pipe 53 for condensation heat exchange, and the condensed liquid refrigerant reaches the first branch 38A through the indoor unit-side liquid pipe 54 and is supplied to the indoor unit-side liquid pipe 54 of the cooling indoor unit 5 to enter the indoor unit heat exchanger 51 for evaporation heat exchange, for example, the indoor unit-side liquid pipe 54 of the heating indoor unit flows from the circle of fig. 4 to the indoor unit-side liquid pipe 54 of the cooling indoor unit 5. Finally, the gaseous refrigerant after the evaporation and heat exchange sequentially passes through the inner machine side air pipe 53 and the refrigeration branch 42 and then reaches the first outer machine side pipe 32, and the subsequent refrigerant circulation process is the same as that in the complete refrigeration mode.

3. Full heating mode

In the heating mode, as shown in fig. 3, the four-way valve 19 is switched to communicate the compressor discharge port with the outer air pipe 23; the first throttling part 35 is closed, the second throttling part 37 is opened, and the heating on-off valve 43 corresponding to the indoor unit 5 in the heating operation is opened to switch on the heating branch 40, and the cooling on-off valve 41 is closed to switch off the cooling branch 42 in the mode converter 3. The third shut-off valve 18 on the heat recovery branch 17 is opened.

As for the outdoor unit 1, as shown in fig. 3, at this time, the heat exchange requirement is large, the first on-off valve 12 in the two outdoor unit heat exchangers 10 is connected to the third branch 11, the second on-off valve 14 is disconnected from the fourth branch 13, the first throttling element 16 is opened, the third on-off valve 18 in the heat recovery branch 17 is disconnected, and at this time, both the two outdoor unit heat exchangers 10 participate in refrigerant circulation.

At this time, the exhaust gas of the compressor 21 passes through the four-way valve 19 and the outer air pipe 23 in this order, and then enters the inlet I of the first gas-liquid separator 31 from the second outer-unit-side pipe 33 through the first air pipe branch 23A and the fifth on-off valve 26B. After gas-liquid separation, the gaseous refrigerant enters the indoor unit heat exchanger 51 from the air outlet pipe 39 and the heating branch 40 and the indoor unit side air pipe 53 of each heating operation indoor unit 5 for condensation heat exchange, and the liquid refrigerant after condensation heat exchange flows out from each indoor unit side liquid pipe 54 and then joins the first branch 38A, and then reaches the first outdoor unit side pipe 32 after passing through the second throttling part 37, the second heat exchanger 34 and the first heat exchanger 36 along the second branch 38B in sequence.

Then, the liquid refrigerant passes through the fourth shut-off valve 26A, the second liquid pipe branch 24B and the outdoor unit liquid pipe 24, then enters the outdoor unit side liquid pipe 15, and enters the outdoor unit heat exchanger 10 for evaporation and heat exchange, the gaseous refrigerant after heat exchange passes through the third branch 11 and the four-way valve 19, then enters the second gas-liquid separator 20, the separated gaseous refrigerant enters the suction port I of the compressor 21, and the compressed high-temperature and high-pressure gaseous refrigerant passes through the oil separator 22 and then reaches the outdoor unit gas pipe 23 through the four-way valve 19, so that a refrigerant circulation passage is formed.

4. Heating mode of main body

As shown in fig. 5, the first throttling part 35 is closed and the second throttling part 37 is opened. Compared with the complete heating mode, for the main heating mode, there are both heating indoor units and cooling indoor units, at this time, the cooling on-off valve 41 corresponding to the cooling indoor unit is opened to switch on the cooling branch 42, and the heating on-off valve 43 is closed to switch off the heating branch 40.

The refrigerant flow direction in the outdoor unit 1 in the main heating mode is similar to that in the full heating mode. The difference is that the liquid refrigerant condensed by each heating operation indoor unit 5 flows out from the indoor unit side liquid pipe 54, and the pressure of the liquid refrigerant generated by the condenser is higher than that of the evaporator, so that the liquid refrigerant can be supplied to the indoor unit side liquid pipe 54 of the cooling operation indoor unit 5 (for example, the lowermost indoor unit 5) under the pressure action and the action of the second throttling component 37, and enters the indoor unit heat exchanger 51 to perform evaporation heat exchange, the gas refrigerant after heat exchange is converged to the first outdoor unit side pipe 32, and the subsequent refrigerant circulation process is the same as the complete heating mode.

5. Full heat recovery mode

In the complete heat recovery mode, as shown in fig. 6, the four-way valve 19 is switched to communicate the compressor discharge port with the outer air pipe 23; in the mode converter 3, the first throttling component 35 is closed, the second throttling component 37 is closed, the heating on-off valve 43 corresponding to the indoor unit 5 in heating operation is opened to switch on the heating branch 40, and the cooling on-off valve 41 is closed to switch off the cooling branch 42; the cooling on-off valve 41 corresponding to the indoor unit 5 in the cooling operation is opened to turn on the cooling branch 42, and the heating on-off valve 43 is closed to turn off the heating branch 40. The third shut-off valve 18 on the heat recovery branch 17 is opened.

At this time, the exhaust gas of the compressor 21 passes through the four-way valve 19 and the outer air pipe 23 in this order, and then enters the inlet I of the first gas-liquid separator 31 from the second outer-unit-side pipe 33 through the second air pipe branch 23B and the fifth on-off valve 26B. After gas-liquid separation, the gaseous refrigerant enters the indoor unit heat exchanger 51 from the heating branch 40 and the indoor unit side gas pipes 53 of the heating operation indoor units 5 (the upper two indoor units 5) through the gas outlet pipe 39 for condensation heat exchange, the liquid refrigerant after condensation heat exchange flows out from the indoor unit side liquid pipes 54 and is supplied to the indoor unit side liquid pipes 54 of the cooling operation indoor units 5 (such as the lower two indoor units 5) under the pressure action, the liquid refrigerant enters the indoor unit heat exchanger 51 for evaporation heat exchange, the gaseous refrigerant after heat exchange is converged to the first outdoor unit side pipe 32, and then directly enters the second gas-liquid separator 20 from the heat recovery branch 17 through the fourth shut-off valve 26A, the second liquid pipe branch 24B and the outdoor unit side pipe 24, and then enters the compressor 21. The outdoor unit heat exchangers 10 do not participate in refrigerant circulation, and the liquid refrigerant generated by the heating indoor unit 5 just can meet the use requirement of the refrigerating indoor unit 5.

Secondly, the present disclosure further provides a control method based on the multi-split system in the above embodiments, in some embodiments, the method includes:

step 101, calculating the heating demand and the cooling demand of a plurality of indoor units 5;

step 102, comparing the magnitude relation between the heating demand and the refrigerating demand, and determining the working mode of the multi-split system according to the comparison result;

and 103, enabling the multi-split system to be in a determined working mode.

Wherein, steps 102 to 103 are executed sequentially, and the executing body may be a control device. The working modes of the multi-split system comprise: at least one of a full cooling mode, a main body cooling mode, a full heat recovery mode, a main body heating mode, and a full heating mode.

According to the embodiment, the corresponding heating demand and the corresponding refrigerating demand can be calculated according to whether the current indoor units 5 are in heating operation or refrigerating operation when in work, and the working mode of the multi-split system can be determined according to the size relation between the heating demand and the refrigerating demand.

In some embodiments, the calculating 101 of the heating demand and the cooling demand of the indoor units 5 includes:

calculating a heating demand according to a total rated capacity of the indoor unit 5 in the heating operation;

the cooling demand is calculated based on the total rated capacity of the indoor unit 5 in the cooling operation.

Each indoor unit 5 has rated capacity, and the control device calculates heating demand and cooling demand according to the rated capacity of the indoor unit 5, so that the working mode of the multi-split air-conditioning system can be determined quickly and accurately.

In some embodiments, if there is only the indoor unit 5 in the cooling operation, the operation mode is the full cooling mode; if the refrigeration demand is greater than the heating demand, the working mode is a main refrigeration mode; if the refrigerating demand is equal to the heating demand, the working mode is a complete heat recovery mode; if the heating demand is greater than the refrigerating demand, the working mode is a main heating mode; and/or if only the indoor unit 5 is in heating operation, the operation mode is the complete heating mode.

In some embodiments, the operation modes of the multi-split system include: at least one of a full cooling mode, a main body cooling mode, a full heat recovery mode, a main body heating mode, and a full heating mode; the method for enabling the multi-split system to work in the determined working mode comprises the following steps:

in the full cooling mode and the main body cooling mode, the first throttling part 35 is opened, and the second throttling part 37 is closed; and/or

In the full heating mode, the main heating mode, and the full heat recovery mode, the first throttling part 35 is closed and the second throttling part 37 is opened.

The embodiment can conveniently realize the switching of the multi-split system between different working modes, and is convenient to control.

In some embodiments, the step 103 of enabling the multi-split system to operate according to the determined operation mode includes:

the cooling on-off valve 41 corresponding to the indoor unit 5 in the cooling operation is opened to turn on the cooling branch 42, and the heating on-off valve 43 is closed to turn off the heating branch 40, and the heating on-off valve 43 corresponding to the indoor unit 5 in the heating operation is opened to turn on the heating branch 40, and the cooling on-off valve 41 is closed to turn off the cooling branch 42.

In some embodiments, the outdoor unit 1 includes: and a first end of the heat recovery branch 17 is communicated with an external liquid pipe 24, a second end of the heat recovery branch 17 is communicated with an inlet of a second gas-liquid separator 20, the inlet of the second gas-liquid separator 20 is communicated with a suction side pipe S of a four-way valve 19, an outlet of the second gas-liquid separator 20 is communicated with a suction port of a compressor 21, and the heat recovery branch 17 is provided with a third cut-off valve 18. The working mode comprises a complete heat recovery mode, and the multi-split system comprises the following working modes according to the determined working mode:

in the full heat recovery mode, the third shut-off valve 18 is made to connect the heat recovery branch 17.

In this embodiment, when the outdoor unit 1 is in the complete heat recovery state, the liquid refrigerant condensed by the indoor unit in the heating state is completely supplied to the indoor unit in the cooling state, the finally formed liquid refrigerant flows from the outdoor unit liquid pipe 24 of the outdoor unit 1 to the gas-liquid separator 20 through the heat recovery branch pipe 17, and the liquid refrigerant does not pass through the outdoor unit heat exchanger 10 of the outdoor unit 1, so that the outdoor unit 1 does not participate in heat exchange. The heat recovery branch 17 is turned off when the outdoor unit 1 is in other operation states, for example, a complete heating operation and a main heating operation.

In some embodiments, the outdoor unit 1 includes at least two outdoor unit heat exchangers 10, and the control method further includes:

step 201, calculating the heat exchange demand of the outdoor unit 1 according to the refrigeration demand and the heating demand; specifically, the heat exchange demand of the outdoor unit is (heating demand-cooling demand) absolute value/rated capacity of the outdoor unit;

step 202, determining the number of the outdoor unit heat exchangers 10 participating in refrigerant circulation in the outdoor unit 1 according to the heat exchange demand of the outdoor unit 1.

Wherein steps 201 and 202 may be performed after step 101. According to the embodiment, the plurality of outdoor unit heat exchangers 10 are arranged, so that the outdoor unit heat exchangers 10 participating in refrigerant circulation can be controlled according to the refrigeration demand and the heating demand of the plurality of indoor units 5 when the multi-split system is in different working modes, the heat exchange capacity of the outdoor unit heat exchangers 10 can be guaranteed to meet the working demand of the indoor units 5, the heat exchange capacity of the outdoor unit heat exchangers 10 can be saved, and more energy can be saved.

A multi-split system provided by the present disclosure is described in detail above. The principles and embodiments of the present disclosure are explained herein using specific examples, which are set forth only to help understand the method and its core ideas of the present disclosure. It should be noted that, for those skilled in the art, it is possible to make several improvements and modifications to the present disclosure without departing from the principle of the present disclosure, and such improvements and modifications also fall within the scope of the claims of the present disclosure.

Claims (8)

1. A multiple on-line system, comprising:

an outdoor unit (1);

each indoor unit (5) comprises an indoor unit heat exchanger (51), and an indoor unit side air pipe (53) and an indoor unit side liquid pipe (54) which are connected to two sides of the indoor unit heat exchanger (51); and

mode switching device (3) comprising:

a first outdoor unit side pipe (32) and a second outdoor unit side pipe (33) both connected to the outdoor unit (1);

a first throttling member (35) and a second throttling member (37); and

a first gas-liquid separator (31) having an inlet of the first gas-liquid separator (31) communicating with one end of the second outer-unit-side pipe (33); the liquid outlet of first vapour and liquid separator (31) is connected with drain pipe (38), the one end process of drain pipe (38) divide into first branch road (38A) and second branch road (38B) behind first throttle part (35), first branch road (38A) with the interior machine side liquid pipe (54) of a plurality of indoor machines (5) all are connected, second branch road (38B) process behind second throttle part (37) with first outer machine side pipe (32) intercommunication.

2. A multi-split system as claimed in claim 1, further comprising a control device configured to open the first throttling part (35) and close the second throttling part (37) in a full cooling mode and a main body cooling mode; and/or in a complete heating mode, a main heating mode and a complete heat recovery mode, the first throttling component (35) is closed, and the second throttling component (37) is opened.

3. A multi-split system as claimed in claim 1, wherein the mode switching means (3) further comprises:

the first ends of the refrigeration branches (42) are connected with the inner machine side air pipes (53) of the indoor machines (5) in a one-to-one correspondence mode, and each refrigeration branch (42) is provided with a refrigeration on-off valve (41); and

the first ends of the heating branches (40) are connected with the inner machine side air pipes (53) of the indoor machines (5) in a one-to-one correspondence mode, and each heating branch (40) is provided with a heating on-off valve (43);

an air outlet pipe (39) is connected to an air outlet of the first gas-liquid separator (31), one end of the air outlet pipe (39) is communicated with the second ends of the heating branches (40), and the second branch (38B) is communicated with the second ends of the refrigerating branches (42) and then communicated with the first outdoor unit side pipe (32).

4. A multi-split system as claimed in claim 3, further comprising a control means configured to open the cooling on-off valve (41) corresponding to the cooling-operation indoor unit (5) and close the heating on-off valve (43), and to open the heating on-off valve (43) corresponding to the heating-operation indoor unit (5) and close the cooling on-off valve (41).

5. A multi-split system as claimed in claim 1, wherein the indoor unit (5) further comprises a third throttling part (52), and the third throttling part (52) is provided on the inner unit side liquid pipe (54).

6. A multi-split system as claimed in claim 1, wherein the outdoor unit (1) comprises: the multi-split air conditioner system further comprises at least two outdoor unit heat exchangers (10), and the control device is configured to determine the number of the outdoor unit heat exchangers (10) participating in refrigerant circulation according to the heat exchange demand of the outdoor unit (1) obtained according to the cooling demand and the heating demand of the indoor units (5).

7. A multi-split system as claimed in claim 1, wherein the outdoor unit (1) comprises:

a compressor (21);

a four-way valve (19);

an outer liquid pipe (24) and an outer air pipe (23), wherein the outer air pipe (23) is communicated with an evaporation side connecting pipe (E) of the four-way valve (19);

a second gas-liquid separator (20), an inlet of the second gas-liquid separator (20) is communicated with a suction side pipe (S) of the four-way valve (19), and an outlet of the second gas-liquid separator (20) is communicated with a suction port of the compressor (21); and

the first end of the heat recovery branch (17) is communicated with the external liquid pipe (24), the second end of the heat recovery branch (17) is communicated with the inlet of the second gas-liquid separator (20), the heat recovery branch (17) is provided with a third cut-off valve (18), and the third cut-off valve (18) is configured to be switched on when the outdoor unit (1) is in a complete heat recovery state.

8. A multi-split system as claimed in claim 1, wherein the outdoor unit (1) further comprises:

a fourth on-off valve (26A) and a fifth on-off valve (26B) configured to communicate with the first outer machine side pipe (32) and the second outer machine side pipe (33) through respective first ports (341); wherein the content of the first and second substances,

the outdoor air pipe (23) comprises a first air pipe branch (23A) and a second air pipe branch (23B), the first ends of the first air pipe branch (23A) and the second ends of the second air pipe branch (23B) are communicated with the second ports (342) of the fourth on-off valve (26A) and the fifth on-off valve (26B), a first one-way valve (25A) only allowing the refrigerant to flow towards the first end of the first air pipe branch (23A) is arranged on the first air pipe branch (23A), and a second one-way valve (25B) only allowing the refrigerant to flow towards the second end of the second air pipe branch (23B) is arranged on the second air pipe branch (23B); and

the outdoor liquid pipe (24) comprises a first liquid pipe branch (24A) and a second liquid pipe branch (24B), the first ends of the first liquid pipe branch and the second end of the second liquid pipe branch are communicated, the second ends of the first liquid pipe branch and the second liquid pipe branch are respectively communicated with a second port (342) of a fifth on-off valve (26B) and a fourth on-off valve (26A), a third one-way valve (25C) allowing the refrigerant to flow towards the second end of the first liquid pipe branch (24A) is arranged on the first liquid pipe branch (24A), and a fourth one-way valve (25D) allowing the refrigerant to flow towards the first end of the second liquid pipe branch (24B) is arranged on the second liquid pipe branch (24B).

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