CN117824104A - Control method of simultaneous cooling and heating air conditioner and simultaneous cooling and heating air conditioner - Google Patents

Abstract

The invention provides a control method of a simultaneous cooling and heating air conditioner and the simultaneous cooling and heating air conditioner, and relates to the technical field of air conditioners, wherein when the control is actually performed, the refrigeration/heating function is realized firstly, then when a heating mode is switched to a refrigerating mode, a corresponding bypass expansion valve is opened until the difference value between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than a first preset value, and then the bypass expansion valve is opened and closed; or when the refrigerating mode is switched to the heating mode, the corresponding liquid-separating expansion valve is opened first until the difference value between the internal heat exchange temperature Tn and the condensing temperature Tw is lower than a second preset value, and then the corresponding high-pressure electromagnetic valve is opened. And finally, the liquid separation expansion valve is transited to the conventional control. After the internal heat exchange temperature Tn reaches the standard, the high-pressure electromagnetic valve or the low-pressure electromagnetic valve is opened, and the pressure difference at the two sides of the valve is reduced to a certain degree, so that the vibration and the flow noise of the piping generated in the refrigerant flow process are smaller, and the problem of larger vibration and noise of the piping is effectively solved.

Description

Control method of simultaneous cooling and heating air conditioner and simultaneous cooling and heating air conditioner

Technical Field

The invention relates to the technical field of air conditioners, in particular to a control method of a simultaneous cooling and heating air conditioner and the simultaneous cooling and heating air conditioner.

Background

In the home air conditioner market, the installation situation gradually transits from one air conditioner to one air conditioner in each room, and 4 air conditioners and 5 air conditioners in each room are in a normal state nowadays. Accordingly, there is an increasing demand for a fixed tractor that can share an outdoor unit and reduce a mounting area, centering on a city. In addition, there is a demand for a stationary trailer in a specific market, such as a small and medium-sized hotel, where the space for installing the outdoor unit is limited. Among these demands, many users further have a demand for a cooling/heating function capable of separately performing cooling/heating settings in a fixed-drag free machine.

In the prior art, the same time of cooling and heating is realized to realize the function of cooling and heating at the same time, namely the same external machine is simultaneously connected with a plurality of internal machines. However, the inventors have found that when the operation mode of the indoor unit is switched from cooling to heating, the high-pressure valve of the outdoor unit needs to be opened, and at this time, piping vibration and refrigerant flow noise are generated. When the temperature is switched from heating to cooling, the low-pressure solenoid valve of the outdoor unit is opened, and the problems of piping vibration and refrigerant flowing sound are similarly caused.

Disclosure of Invention

The invention solves the problems of pipe vibration and refrigerant flowing noise generated when the mode is switched under the function of cooling and heating.

In order to solve the problems, the invention adopts the following technical proposal.

In one aspect, the present invention provides a control method of a simultaneous cooling and heating air conditioner, which is suitable for a simultaneous cooling and heating air conditioner, the simultaneous cooling and heating air conditioner including an outdoor unit and a plurality of indoor units connected with the outdoor unit at the same time, the control method comprising:

setting at least one indoor unit as a heating mode, opening a liquid-separating expansion valve and a high-pressure electromagnetic valve of a corresponding pipeline, and closing a corresponding low-pressure electromagnetic valve and a bypass expansion valve, wherein the bypass expansion valve and the low-pressure electromagnetic valve are connected in parallel and bypass through a bypass pipeline;

when one of the indoor units is switched from a heating mode to a refrigerating mode, opening the corresponding bypass expansion valve until the difference value between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than a first preset value, opening the corresponding low-pressure electromagnetic valve of the corresponding pipeline and closing the corresponding bypass expansion valve;

or, setting at least one indoor unit to be in a refrigerating mode, opening a liquid separating expansion valve and a low-pressure electromagnetic valve of a corresponding pipeline, and closing a corresponding high-pressure electromagnetic valve and a bypass expansion valve;

when one of the indoor units is switched from a refrigerating mode to a heating mode, opening the liquid-separating expansion valve of the corresponding pipeline until the difference value between the internal heat exchange temperature Tn and the condensing temperature Tw is lower than a second preset value, and opening the high-pressure electromagnetic valve of the corresponding pipeline;

And (5) the liquid separation expansion valve is transited to conventional control, so that mode switching is completed.

According to the control method for the simultaneous cooling and heating air conditioner, provided by the embodiment of the invention, the two ends of the original low-pressure electromagnetic valve are additionally provided with the bypass pipeline, the bypass expansion valve is arranged on the bypass pipeline, when the control is actually performed, the refrigeration/heating control is realized firstly, at least one indoor unit is set to be a heating mode, the liquid-separating expansion valve and the high-pressure electromagnetic valve of the corresponding pipeline are opened, the corresponding low-pressure electromagnetic valve and the bypass expansion valve are closed, then when one indoor unit is switched from the heating mode to the cooling mode, the corresponding bypass expansion valve is opened, the refrigerant flows, the internal heat exchange temperature Tn is reduced, and the corresponding low-pressure electromagnetic valve is opened and the corresponding bypass expansion valve is closed after the difference value between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than a first preset value; or at least one indoor unit is set to be in a refrigerating mode, a liquid separation expansion valve and a low-pressure electromagnetic valve of a corresponding pipeline are opened, and a corresponding high-pressure electromagnetic valve and a bypass expansion valve are closed; when one of the indoor units is switched from a refrigerating mode to a heating mode, the liquid separating expansion valve of the corresponding pipeline is opened, the refrigerant flows, the internal heat exchange temperature Tn is increased, and the corresponding high-pressure electromagnetic valve is opened after the difference value between the internal heat exchange temperature Tn and the condensing temperature Tw is lower than a second preset value. And finally, the liquid separation expansion valve is transited to the conventional control, so that the mode switching is completed. Compared with the prior art, the difference value between the internal heat exchange temperature Tn and the evaporation temperature Tz or the condensation temperature Tw can represent the corresponding pressure difference, and the embodiment of the invention enables the high-pressure electromagnetic valve or the low-pressure electromagnetic valve to be opened after the internal heat exchange temperature Tn reaches the standard by reasonably adjusting the internal heat exchange temperature Tn.

Further, the step of opening the corresponding bypass expansion valve until the difference between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than a first preset value, opening the corresponding low-pressure electromagnetic valve of the corresponding pipeline and closing the corresponding bypass expansion valve includes:

closing the high-pressure electromagnetic valve and the liquid-separating expansion valve of the corresponding pipeline;

setting the liquid separation expansion valve of the corresponding pipeline to be a first preset opening degree;

opening a bypass expansion valve on the corresponding bypass pipeline;

acquiring an internal heat exchange temperature Tn and an evaporation temperature Tz of the indoor unit in a mode switching state;

opening a low-pressure solenoid valve after the difference between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than a first preset value;

and closing the corresponding bypass expansion valve.

When the heating is switched to the refrigeration actual control, the control method of the fixed-drawing cooling and heating air conditioner provided by the embodiment of the invention firstly closes the high-pressure electric valve and the liquid-separating expansion valve, completely cuts off the flow pipeline, then sets the liquid-separating expansion valve to be at a first preset opening degree, and under the condition, opens the bypass expansion valve on the corresponding bypass pipeline, so that the refrigerant flows into the air suction side of the compressor through the bypass expansion valve and the bypass pipeline, the pressure is reduced, and the low-pressure electric valve can be completely opened after the difference value between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than the first preset value. Because the bypass expansion valve on the bypass pipe is used for opening the circulation pipeline, compared with the direct opening of the low-pressure electromagnetic valve, the flow speed of the refrigerant can be effectively restrained, and vibration and refrigerant flowing sound can be further restrained.

Further, the step of opening the bypass expansion valve on the corresponding bypass line includes:

gradually opening the corresponding bypass expansion valve on the bypass pipeline according to a preset opening rate so as to gradually reduce the resistance of the bypass pipeline;

when the falling rate of the internal heat exchange temperature Tn exceeds the preset temperature falling rate, maintaining the corresponding current opening preset time of the bypass expansion valve.

According to the control method for the fixed-drawing cooling and heating air conditioner, the bypass expansion valve is gradually opened in the opening process, and the bypass expansion valve is not in one step, so that the flow speed of a refrigerant can be further and effectively controlled, namely, the refrigerant is prevented from rapidly flowing into the air suction side of the compressor, and vibration and refrigerant flowing sound are further restrained. Meanwhile, when the internal heat exchange temperature Tn drops too fast, the opening speed of the bypass expansion valve is too fast, so that the refrigerant flowing speed is too fast, and the problem of new refrigerant flowing sound or vibration can be possibly caused at the moment.

Further, the first preset opening is 1/5-2/5 of the maximum opening of the liquid separation expansion valve, and the first preset value is 10 ℃; the preset opening rate is 1/500-1/200 of the maximum opening of the bypass expansion valve per second, the preset temperature drop rate is 0.5 ℃/s, and the preset time is 5s.

According to the control method for the fixed-drawing cooling and heating air conditioner, the first preset opening and the preset opening rate are limited, so that on one hand, the phenomenon that the refrigerant is not controlled due to overlarge internal expansion opening can be avoided, on the other hand, the opening speed of the low-pressure electromagnetic valve can be reasonably limited, and the problem of refrigerant flowing sound or vibration due to overlarge opening speed is avoided. Meanwhile, the preset temperature drop rate and the preset time are limited, so that the flow speed of the refrigerant can be accurately controlled, the flow speed of the refrigerant is further slowed down, and the problems of refrigerant flowing sound or vibration are avoided.

Further, the bypass pipeline is a capillary pipeline, and the resistance of the capillary pipeline is larger than a preset resistance, so that the falling rate of the internal heat exchange temperature Tn is lower than a preset temperature falling rate.

According to the control method of the fixed-drawing cooling and heating air conditioner, the refrigerant flows in a capillary pipeline mode, noise caused by rapid flow of the refrigerant is generated under the condition that the resistance of the capillary pipe is small, and time is needed for changing the interior of the indoor unit to be low pressure under the condition that the resistance of the capillary pipe is large.

Further, the step of opening the high-pressure electromagnetic valve of the corresponding pipeline after the difference between the internal heat exchange temperature Tn and the condensation temperature Tw is lower than a second preset value, includes:

closing the corresponding pipeline;

setting the liquid separation expansion valve of the corresponding pipeline to be a second preset opening degree;

acquiring an internal heat exchange temperature Tn and a condensation temperature Tw of the indoor unit in a mode switching state;

and opening the corresponding high-pressure electromagnetic valve when the difference value between the internal heat exchange temperature Tn and the condensing temperature Tw is lower than a second preset value.

According to the control method for the fixed-drawing cooling and heating air conditioner, when cooling is switched to heating actual control, the low-pressure electromagnetic valve on the pipeline corresponding to the indoor unit needing mode switching is firstly closed, the liquid-dividing expansion valve is set to a second preset opening, at the moment, a refrigerant starts to flow back to other indoor units in a heating state through the liquid-dividing expansion valve, so that pressure equalization is carried out on the refrigerant and other indoor units in the heating state, in this case, the internal heat exchange temperature Tn of the indoor unit needing mode switching starts to rise, finally, the high-pressure electromagnetic valve is opened after the internal heat exchange temperature Tn meets the requirement, and as the liquid-dividing expansion valve has carried out pressure equalization processing on the refrigerant, the pressure difference at two sides of the high-pressure electromagnetic valve is smaller, and piping vibration and flowing noise generated in the refrigerant flowing process are smaller, so that the problems of the prior art that the piping vibration and the noise are larger are further solved.

Further, after the step of obtaining the internal heat exchange temperature Tn and the condensation temperature Tw of the indoor unit in the mode switching state, the method further includes:

acquiring heat exchange temperature Tq of the indoor unit in the other heating mode state;

and when the rising rate of the internal heat exchange temperature Tn exceeds a preset temperature rising rate and/or the heat exchange temperature Tq of the indoor unit in the state of the other heating modes is lower than a preset temperature, reducing the third preset opening of the liquid separation expansion valve.

According to the control method for the simultaneous cooling and heating air conditioner, when the rising rate of the internal heat exchange temperature Tn exceeds the preset rising rate, the flowing speed of the refrigerant is increased, and the problem of refrigerant flowing sound or vibration can possibly occur, so that the opening degree of the liquid-separating expansion valve can be reduced to reduce the flow speed of the refrigerant, and vibration or refrigerant flowing noise in the regulation and control process is avoided. In addition, when the refrigerant is subjected to pressure equalizing, the condensation pressure of the indoor unit in the heating mode can be reduced, and the problem of reduction of the air outlet temperature can possibly occur, so that the opening degree of the liquid-separating expansion valve can be reduced, and the heating function of the indoor unit in the heating mode is prevented from being influenced.

Further, the second preset opening is 1/5-2/5 of the maximum opening of the liquid separation expansion valve; the third preset opening is 1/500-1/200 of the maximum opening of the liquid separation expansion valve; the second preset value is 10 ℃; the preset temperature rise rate is 0.5 ℃/s; the preset temperature is 46 ℃.

According to the control method for the simultaneous cooling and heating air conditioner, provided by the embodiment of the invention, the initial opening degree and the adjustment opening degree of the liquid separation expansion valve are limited, so that the refrigerant can be effectively ensured to be subjected to pressure equalization through the liquid separation expansion valve to reduce the pressure difference, noise generated in the pressure equalization process due to overlarge initial opening degree is avoided, meanwhile, the excessive influence on the refrigerant flow when the opening degree of the liquid separation expansion valve is adjusted can be avoided, the reliable operation of the whole air conditioner in the pressure equalization process is ensured, and the comfort of a user is improved. Through the reasonable limitation to the preset temperature rise rate, the noise critical value in the pressure equalizing process can be accurately defined, noise influence experience is avoided, and the refrigerant is guaranteed to flow fast to realize pressure equalizing as soon as possible. Meanwhile, through reasonable definition of preset temperature, the pressure equalizing process can be accurately prevented from affecting other heating indoor units which are normally used, and meanwhile, the refrigerant is guaranteed to flow fast so as to realize pressure equalizing as soon as possible.

Further, after the step of setting the liquid-dividing expansion valve of the corresponding pipeline to the second preset opening, the control method further includes:

and stopping the fan of the indoor unit in the mode switching state.

According to the control method for the simultaneous cooling and heating air conditioner, provided by the embodiment of the invention, the corresponding fans are stopped after the liquid-separating expansion valve is opened, so that air outlet at unnecessary temperature in the mode switching process can be avoided, and the user experience is improved.

In another aspect, the present invention provides a simultaneous cooling and heating air conditioner, which is suitable for the aforesaid simultaneous cooling and heating air conditioner, the simultaneous cooling and heating air conditioner comprising:

a plurality of indoor units;

the outdoor unit comprises an outdoor heat exchanger, a compressor assembly, a high-pressure gas collecting tube, a low-pressure gas collecting tube and a liquid distributing head, wherein the liquid distributing head is connected with a plurality of indoor units through a plurality of liquid distributing pipelines respectively, and the outdoor heat exchanger is connected with the liquid distributing head through pipelines; the compressor assembly is connected with the outdoor heat exchanger through a pipeline; the high-pressure gas collecting pipe is connected with the compressor assembly through a pipeline and is connected with a plurality of indoor units through a plurality of high-pressure gas distributing pipelines respectively; the low-pressure gas collecting pipe is connected with the compressor assembly through a pipeline and is connected with a plurality of indoor units through a plurality of low-pressure gas distributing pipelines respectively;

the compressor assembly is used for compressing a refrigerant and adjusting the flow direction of the refrigerant, each liquid separation pipeline is provided with a liquid separation expansion valve, each high-pressure gas separation pipeline is provided with a high-pressure electromagnetic valve, and the high-pressure electromagnetic valves are used for being conducted in a heating state so that the refrigerant flows from the high-pressure gas collecting head to the corresponding indoor unit; the low-pressure air distribution pipeline is provided with a low-pressure electromagnetic valve, the low-pressure electromagnetic valve is used for being conducted in a refrigerating state, so that a refrigerant flows to the low-pressure air collection pipe from the corresponding indoor unit, two ends of each low-pressure electromagnetic valve are further provided with bypass pipelines, the bypass pipelines are provided with bypass expansion valves, and the bypass expansion valves and the low-pressure electromagnetic valves are connected in parallel for bypass.

Drawings

FIG. 1 is a schematic diagram of a prior art for switching cooling and heating of an air conditioner to heating at the same time;

FIG. 2 is a schematic diagram of a prior art cold-warm simultaneous space-time modulated heat switch to refrigeration;

fig. 3 is a schematic structural diagram of an air conditioner with simultaneous cooling and heating function according to an embodiment of the present invention;

fig. 4 is a schematic diagram of steps of a control method of a simultaneous cooling and heating air conditioner according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a simultaneous cooling and heating air conditioner according to another preferred embodiment of the present invention.

Reference numerals illustrate:

100-cooling and heating air conditioner at the same time; 110-an outdoor unit; 111-an outdoor heat exchanger; 112-a compressor assembly; 113-a high-pressure gas collecting tube; 114-a low-pressure gas collecting tube; 115-a liquid separation head; 116-a liquid separation pipeline; 117-high pressure gas separation pipeline; 118-a low pressure gas separation pipeline; 120-indoor units; 130-a liquid separation expansion valve; 140-high pressure solenoid valve; 150-a low pressure solenoid valve; 160-bypass line; 161-bypass expansion valve.

Detailed Description

As disclosed in the background art, the prior art is directed to the simultaneous cooling and heating to achieve the simultaneous cooling and heating function, and the conventional control means thereof is as disclosed in patent CN 202211160483.2. However, at the same time as the cooling and heating, when the operation mode of the indoor unit is switched from cooling to heating, the high-pressure electromagnetic valve of the outdoor unit needs to be opened, and at this time, problems of piping vibration and refrigerant flowing sound occur. When the temperature is switched from heating to cooling, the low-pressure solenoid valve of the outdoor unit is opened, and the problems of piping vibration and refrigerant flowing sound are similarly caused.

As a result of the study by the inventors, it was found that the cause of the vibration of the piping and the noise of the refrigerant flow is derived from the refrigerant pressure difference, and when the cooling is changed from the cooling to the heating, as shown in fig. 1, the high-pressure circuit (the discharge side of the compressor) is connected to the portion of the indoor unit in the low-pressure state, and the abrupt refrigerant flow is caused by the pressure difference between the portions. On the other hand, when the temperature is changed from heating to cooling, as shown in fig. 2, a high-pressure portion of the indoor unit is connected to a low-pressure circuit (suction side of the compressor), and a sudden refrigerant flow is caused by a pressure difference between the low-pressure circuit and the low-pressure circuit.

In order to solve the above problems, the present invention provides a control method of a simultaneous cooling and heating air conditioner and a simultaneous cooling and heating air conditioner, and in order to make the above objects, features and advantages of the present invention more obvious and understandable, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

First embodiment

Referring to fig. 3 and 4 in combination, the present embodiment provides a control method of a simultaneous cooling and heating air conditioner 100, which is suitable for a simultaneous cooling and heating air conditioner 100, and by using the control method, the problems of piping vibration and refrigerant flow noise generated in a simultaneous cooling and heating mode switching process can be solved, and user experience is improved.

The embodiment also provides a simultaneous cooling and heating air conditioner 100, where the simultaneous cooling and heating air conditioner 100 includes an outdoor unit 110 and a plurality of indoor units 120 connected with the outdoor unit 110 at the same time, the outdoor unit 110 includes an outdoor heat exchanger 111, a compressor assembly 112, a high-pressure gas collecting tube 113, a low-pressure gas collecting tube 114 and a liquid distributing head 115, the liquid distributing head 115 is connected with the plurality of indoor units 120 through a plurality of liquid distributing pipes 116, and the outdoor heat exchanger 111 is connected with the liquid distributing head 115 through pipes; the compressor assembly 112 is connected to the outdoor heat exchanger 111 through a pipe; the high-pressure gas collecting pipe 113 is connected with the compressor assembly 112 through a pipeline and is respectively connected with the plurality of indoor units 120 through a plurality of high-pressure gas distributing pipelines 117; the low-pressure gas collecting pipe 114 is connected with the compressor assembly 112 through a pipeline and is respectively connected with the plurality of indoor units 120 through a plurality of low-pressure gas distributing pipelines 118; the compressor assembly 112 is used for compressing a refrigerant and adjusting the flow direction of the refrigerant, each liquid separation pipeline 116 is provided with a liquid separation expansion valve 130, each high-pressure gas separation pipeline 117 is provided with a high-pressure electromagnetic valve 140, and the high-pressure electromagnetic valves 140 are used for being conducted in a heating state so that the refrigerant flows from the high-pressure gas collecting head to the corresponding indoor unit 120; each low-pressure gas distribution pipeline 118 is provided with a low-pressure electromagnetic valve 150, the low-pressure electromagnetic valve 150 is used for being conducted in a refrigeration state so that the refrigerant flows from the corresponding indoor unit 120 to the low-pressure gas collection pipe 114, two ends of each low-pressure electromagnetic valve 150 are also provided with bypass pipelines 160, the bypass pipelines 160 are provided with bypass expansion valves 161, and the bypass expansion valves 161 and the low-pressure electromagnetic valves 150 are connected in parallel for bypass.

In this embodiment, by additionally providing the bypass pipeline 160 and additionally providing the bypass expansion valve 161 on the bypass pipeline 160, the flow direction of the refrigerant in the pipeline can be adjusted by the bypass expansion valve 161 when the mode is switched, and the low-pressure electromagnetic valve 150 is opened after the mode is adjusted in place, so that the problem of refrigerant flowing sound or pipeline vibration caused by overlarge pressure difference caused by directly opening the low-pressure electromagnetic valve 150 can be avoided. And the original pipeline structure is not required to be changed, so that the cost is saved.

The embodiment provides a control method of an air conditioner 100 with simultaneous cooling and heating, which specifically includes the following steps:

s1: at least one indoor unit 120 is set to a heating mode, and a liquid separation expansion valve 130 and a high-pressure electromagnetic valve 140 of the corresponding pipeline are opened, and a corresponding low-pressure electromagnetic valve 150 and a bypass expansion valve 161 are closed.

The bypass expansion valve 161 and the low-pressure electromagnetic valve 150 are bypassed in parallel through the bypass pipeline 160, and it should be noted that, in the parallel bypass in this embodiment, two ends of the bypass pipeline 160 are respectively connected to two ends of the low-pressure electromagnetic valve 150, so as to form a bypass structure, and the bypass expansion valve 161 is disposed on the bypass pipeline 160, so that the flow direction of the refrigerant in the bypass pipeline 160 can be controlled.

S2: at least one indoor unit 120 is set to a cooling mode, and a liquid separation expansion valve 130 and a low-pressure electromagnetic valve 150 of the corresponding pipeline are opened, and a corresponding high-pressure electromagnetic valve 140 and a bypass expansion valve 161 are closed.

Specifically, step S1 and step S2 are alternatively performed, and may be set according to actual heating/cooling requirements. When step S1 is performed, all or part of the indoor unit 120 may be set to the heating mode, and when step S2 is performed, all or part of the indoor unit may be set to the cooling mode.

After at least one indoor unit 120 is set to the heating mode, when one of the indoor units 120 is switched from the heating mode to the cooling mode, step S3 is performed: and opening the corresponding bypass expansion valve 161 until the difference between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than a first preset value, opening the low-pressure electromagnetic valve 150 of the corresponding pipeline and closing the corresponding bypass expansion valve 161.

After setting at least one indoor unit 120 to the cooling mode, when one of the indoor units 120 is switched from the cooling mode to the heating mode, step S4 is executed: and opening the liquid separating expansion valve 130 of the corresponding pipeline until the difference value between the internal heat exchange temperature Tn and the condensing temperature Tw is lower than a second preset value, and then opening the high-pressure electromagnetic valve 140 of the corresponding pipeline.

S5: the split expansion valve 130 is transitioned to conventional control to complete the mode switch.

It is to be noted that, as a result of the study by the inventors, it was found that noise caused by vibration of the piping and abrupt flow of the refrigerant is mainly due to an excessively large pressure difference at the time of switching, and noise is generated when the pressure difference is usually equal to or higher than a threshold value, for example, equal to or higher than 0.5MPa, in this embodiment, the pressure difference at the time of switching the circuit can be controlled to be equal to or lower than 0.5MPa by controlling the split expansion valve 130 or the bypass expansion valve 161, and the pressure difference can be represented by a difference between the internal heat exchange temperature Tn and the evaporation temperature Tz or the condensation temperature Tw, and both the first preset value and the second preset value can represent the pressure difference to be equal to or lower than 0.5 MPa. The temperature and pressure used in this embodiment are those used when R32 and R410A refrigerants are used. The control method is also applicable to other refrigerants, but the pressure and the temperature can be changed.

In this embodiment, the bypass line 160 is added to both ends of the original low-pressure electromagnetic valve 150, and the bypass expansion valve 161 is provided on the bypass line 160, so that when the control is actually performed, the cooling/heating control is first implemented, at least one indoor unit 120 is set to be in a heating mode at the beginning, the liquid-separating expansion valve 130 and the high-pressure electromagnetic valve 140 of the corresponding lines are opened, and the corresponding low-pressure electromagnetic valve 150 and the bypass expansion valve 161 are closed. Then, when one of the indoor units 120 is switched from the heating mode to the cooling mode, the corresponding bypass expansion valve 161 is opened, the refrigerant flows, the internal heat exchange temperature Tn is reduced, the corresponding low-pressure electromagnetic valve 150 is opened and the corresponding bypass expansion valve 161 is closed after the difference between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than a first preset value, or at least one indoor unit 120 is set to the cooling mode at the beginning, the liquid separation expansion valve 130 and the low-pressure electromagnetic valve 150 of the corresponding pipeline are opened, and the corresponding high-pressure electromagnetic valve 140 and the bypass expansion valve 161 are closed. When one of the indoor units 120 is switched from the cooling mode to the heating mode, the liquid-separating expansion valve 130 of the corresponding pipeline is opened, the refrigerant flows, the internal heat exchange temperature Tn is increased, and the corresponding high-pressure electromagnetic valve 140 is opened after the difference between the internal heat exchange temperature Tn and the condensing temperature Tw is lower than the second preset value. Finally, the split expansion valve 130 is transitioned to conventional control, thereby completing the mode switch. The difference between the internal heat exchange temperature Tn and the evaporation temperature Tz or the condensation temperature Tw can represent the corresponding pressure difference, and the embodiment of the invention enables the high-pressure electromagnetic valve 140 or the high-pressure electromagnetic valve 150 to be opened after the internal heat exchange temperature Tn reaches the standard by reasonably adjusting the internal heat exchange temperature Tn.

Further, in the present embodiment, when the indoor unit 120 is switched from the heating mode to the cooling mode and the step S3 is performed, the method may specifically include the following steps:

s31: the high-pressure solenoid valve 140 and the liquid-dividing expansion valve 130 of the corresponding pipeline are closed.

Specifically, when the heating mode is switched to the cooling mode, the high-pressure solenoid valve 140 may be closed first, and the liquid-separating expansion valve 130 of the corresponding pipe may be completely closed, so that the refrigerant is temporarily stopped.

S32: the liquid-dividing expansion valve 130 of the corresponding line is set to a first preset opening degree.

Specifically, the indoor fan may be maintained at the rotation speed before the operation mode is changed, and the liquid-dividing expansion valve 130 corresponding to the indoor unit 120 in the switching mode state is set to a first preset opening, where the first preset opening may be 1/5-2/5 of the maximum opening of the liquid-dividing expansion valve 130, where the maximum opening of the liquid-dividing expansion valve 130 may be 500pls, and the liquid-dividing expansion valve 130 may be set to 120pls.

S33: the bypass expansion valve 161 on the corresponding bypass line 160 is opened.

Specifically, by opening the bypass expansion valve 161 on the corresponding bypass line 160, the refrigerant can flow into the suction side of the compressor through the bypass expansion valve 161 and the bypass line 160, so as to reduce the pressure, and the low-pressure solenoid valve 150 can be completely opened until the difference between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than the first preset value. Since the bypass expansion valve 161 of the bypass line 160 opens the flow line, the flow velocity of the refrigerant can be effectively suppressed as compared with the case where the low-pressure solenoid valve 150 is directly opened, thereby further suppressing vibration and refrigerant flow noise.

Specifically, when the bypass expansion valve 161 is opened, it may be preferable to gradually open the bypass expansion valve 161 on the corresponding bypass line 160 at a preset opening rate to gradually reduce the resistance of the bypass line 160; and when the falling rate of the internal heat exchange temperature Tn exceeds the preset temperature falling rate, the current opening of the bypass expansion valve 161 is maintained for a preset time.

The preset opening rate may be 1/500-1/200 of the maximum opening of the bypass expansion valve 161, the maximum opening of the bypass expansion valve 161 may be 500pls, and the bypass expansion valve 161 may be gradually opened at a speed of 2 pls/s. Since the bypass expansion valve 161 is gradually opened and is not in place in one step, the flow rate of the refrigerant can be further effectively controlled, that is, the refrigerant is prevented from rapidly flowing into the suction side of the compressor, thereby further suppressing vibration and refrigerant flow noise.

It should be noted that, when the internal heat exchange temperature Tn drops too fast, it is indicated that the opening speed of the bypass expansion valve 161 is too fast, resulting in too fast refrigerant flow speed, which may cause new refrigerant flow sound or vibration problem at this time, so the current opening of the bypass expansion valve 161 is maintained for a certain time when the internal heat exchange temperature Tn drops too fast, so as to slow down the refrigerant flow speed, and avoid the refrigerant flow sound or vibration problem brought in the adjustment process.

S34: the internal heat exchange temperature Tn and the evaporation temperature Tz of the indoor unit 120 in the mode switching state are acquired.

Specifically, the internal heat exchange temperature Tn is the heat exchanger temperature of the indoor unit 120 in the operation mode change, that is, the temperature at a in fig. 3, and when the high-pressure sensor is not mounted, the evaporation temperature Tz is the temperature of the outdoor heat exchanger 111 of the outdoor unit 110, that is, the temperature of the heat exchanger at B in fig. 3, and is monitored by the temperature sensor, and is the same as the average value of the temperatures of the heat exchangers of the cooling operation indoor unit 120. When the high-pressure sensor is mounted, the evaporation temperature Tz is a low-pressure saturation temperature measured by the high-pressure sensor.

S35: after the difference between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than the first preset value, the low-pressure solenoid valve 150 is opened.

Specifically, the first preset value may be 10 ℃, when the difference between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than 10 ℃, it indicates that the pressure difference between the two sides of the low pressure solenoid valve 150 is lower than 0.5MPa, and at this time, the low pressure solenoid valve 150 may be completely opened without generating vibration and flow noise problems.

S36: the corresponding bypass expansion valve 161 is closed.

Specifically, after the low-pressure solenoid valve 150 is opened, the refrigerant flows through the main passage, and at this time, the bypass expansion valve 161 may be closed, thereby preventing the refrigerant from flowing through the bypass passage 160.

In this embodiment, the first preset opening is 1/5-2/5 of the maximum opening of the liquid-separating expansion valve 130, and the first preset value is 10 ℃; the preset opening rate is 1/500-1/200 of the maximum opening of the bypass expansion valve 161 per second, the preset temperature drop rate is 0.5 ℃/s, and the preset time is 5s. By limiting the first preset opening and the preset opening rate, on one hand, uncontrolled refrigerant caused by overlarge internal expansion opening can be avoided, and on the other hand, the opening speed of the low-pressure electromagnetic valve 150 can be reasonably limited, so that the problem of refrigerant flowing sound or vibration caused by overlarge opening speed is avoided. Meanwhile, the preset temperature drop rate and the preset time are limited, so that the flow speed of the refrigerant can be accurately controlled, the flow speed of the refrigerant is further slowed down, and the problems of refrigerant flowing sound or vibration are avoided.

In other preferred embodiments of the present invention, referring to fig. 5, the bypass line 160 may be a capillary line, and the resistance of the capillary line is greater than the preset resistance so that the decrease rate of the internal heat exchange temperature Tn is lower than the preset temperature decrease rate. At this time, when the bypass expansion valve 161 is opened, the bypass expansion valve 161 may be directly fully opened, or the bypass expansion valve 161 may be replaced with an electromagnetic cut valve, as shown in fig. 5. The resistance of the capillary pipeline is related to the diameter and the length of the capillary pipeline, and the diameter and the length of the capillary pipeline can be limited, so that the resistance of the capillary pipeline is larger than the preset resistance. By adopting the capillary tube way to make the refrigerant flow, under the condition that the resistance of the capillary tube is small, the noise problem caused by the rapid flow of the refrigerant is generated, under the condition that the resistance of the capillary tube is large, the indoor unit 120 needs time to be changed into low pressure.

Further, in the present embodiment, when the indoor unit 120 is switched from the cooling mode to the heating mode and the step S4 is executed, the method may specifically include the steps of:

s41: the corresponding line is closed with the low pressure solenoid valve 150.

Specifically, the low-pressure solenoid valve 150 may be closed first so that the flow of the additional refrigerant in the refrigeration circuit is stopped, thereby stopping the refrigeration.

S42: the liquid-dividing expansion valve 130 of the corresponding line is set to a second preset opening degree.

Specifically, the second preset opening degree may be 1/5 to 2/5 of the maximum opening degree of the liquid separation expansion valve 130. Preferably, the maximum opening degree of the liquid separation expansion valve 130 may be 500pls here, and the opening degree of the liquid separation expansion valve 130 may be set to 120pls here.

S33: the blower of the indoor unit 120 is stopped in the mode switching state.

Specifically, after the liquid separation expansion valve 130 is opened, the corresponding fan is stopped, so that air outlet at unnecessary temperature in the mode switching process can be avoided, and the user experience is improved.

S34: the internal heat exchange temperature Tn and the condensation temperature Tw of the indoor unit 120 in the mode switching state are acquired.

Specifically, the internal heat exchange temperature Tn refers to the temperature of the heat exchanger of the indoor unit 120, i.e., the temperature of the heat exchanger at a in fig. 3, when the operation mode is switched, and can be monitored by a temperature sensor. When the high-pressure sensor is not mounted, the condensation temperature Tw, which is the same as the average temperature of the heat exchanger of the heating operation indoor unit 120, is the temperature of the outdoor heat exchanger 111 of the outdoor unit 110, that is, the temperature of the heat exchanger at B in fig. 3, and can be monitored by the temperature sensor. When the high-pressure sensor is mounted, the condensing temperature Tw is a high-pressure saturation temperature measured by the high-pressure sensor.

S35: the heat exchange temperature Tq of the indoor unit 120 in the remaining heating mode state is obtained.

Specifically, the heat exchange temperature Tq of the indoor unit 120 in the heating mode refers to the temperature of the heat exchanger of the indoor unit 120 in the remaining heating mode, i.e., the temperature of the heat exchanger at C in fig. 3, which can be detected by a temperature sensor, and the temperature can represent the heating performance of the indoor unit 120 in the remaining heating mode.

When the rising rate of the internal heat exchange temperature Tn exceeds the preset rising rate, step S36 is executed: the third preset opening of the liquid-separating expansion valve 130 is reduced.

Or, when the heat exchange temperature Tq of the indoor unit 120 in the remaining heating mode state is lower than the preset temperature, step S36 is performed: the third preset opening of the liquid-separating expansion valve 130 is reduced.

Of course, step S36 is also performed when the rising rate of the internal heat exchange temperature Tn exceeds the preset rising rate and the heat exchange temperature Tq of the indoor unit 120 in the remaining heating mode state is lower than the preset temperature.

Specifically, when the indoor unit 120 is equalized to a high pressure, the flow velocity of the refrigerant increases, a refrigerant flow sound may occur, and the condensation pressure of the indoor unit 120 in the heating operation decreases, and the air outlet temperature may decrease. Wherein the preset temperature rise rate may be 0.5 ℃/sec, the preset temperature may be 46 ℃, and the second preset opening is 1/500-1/200 of the maximum opening of the liquid-dividing expansion valve 130, preferably the second preset opening may be 5pls. Step S36 needs to be performed when in any of the following cases:

1. When the temperature rising speed of the internal heat exchange temperature is more than 0.5 ℃/s, the refrigerant rapidly flows, namely, the degree that the flowing sound of the refrigerant can be heard indoors is achieved.

2. The heat exchange temperature Tq of the heating indoor unit 120 is 46 ℃ or lower.

It should be noted that, in this embodiment, when the rising rate of the internal heat exchange temperature Tn exceeds the preset rising rate, the flow rate of the refrigerant may become large, and a refrigerant flowing sound may occur, so that the opening of the liquid-separating expansion valve 130 may be adjusted to reduce the flow rate of the refrigerant, so as to avoid vibration or refrigerant flowing noise in the adjustment process. In addition, when the refrigerant is subjected to pressure equalizing, the condensation pressure of the indoor unit 120 in the heating mode is reduced, and the problem of reduction of the air outlet temperature may occur, so that the opening degree of the liquid-separating expansion valve 130 may be reduced, so as to avoid the influence on the heating function of the indoor unit 120 in the heating mode.

S37: and opening the corresponding high-pressure solenoid valve 140 when the difference between the internal heat exchange temperature Tn and the condensing temperature Tw is lower than a second preset value.

Specifically, the difference between the internal heat exchange temperature Tn and the condensing temperature Tw can represent the pressure difference across the high-pressure solenoid valve 140, and typically, the difference between the internal heat exchange temperature Tn and the condensing temperature Tw is less than 10 ℃ and the pressure difference across the high-pressure solenoid valve is less than 0.5MPa.

When step S3 is actually performed, that is, when the cooling is switched to the heating is actually controlled, the low-pressure electromagnetic valve 150 on the pipeline corresponding to the indoor unit 120 requiring mode switching is closed first, the liquid-dividing expansion valve 130 is set to the second preset opening, at this time, the refrigerant starts to flow back to other indoor units 120 in the heating state through the liquid-dividing expansion valve 130, so as to perform pressure equalization with other indoor units 120 in the heating state, in this case, the internal heat exchange temperature Tn of the indoor unit 120 in the mode switching starts to rise, and finally, the high-pressure electromagnetic valve 140 is opened after the internal heat exchange temperature Tn reaches the requirement, because the liquid-dividing expansion valve 130 has performed pressure equalization processing on the refrigerant, the pressure difference at both sides of the high-pressure electromagnetic valve 140 is smaller, and the piping vibration and flow noise generated in the refrigerant flow process are smaller, so that the problem of the prior art that the piping vibration and noise are larger is further solved.

Further, the second preset opening is 1/5-2/5 of the maximum opening of the liquid separation expansion valve 130; the third preset opening is 1/500-1/200 of the maximum opening of the liquid separation expansion valve 130; the second preset value is 10 ℃; the preset temperature rise rate is 0.5 ℃/s; the preset temperature was 46 ℃. The initial opening degree and the adjustment opening degree of the liquid separation expansion valve 130 are limited, so that the refrigerant can be effectively ensured to be subjected to pressure equalization through the liquid separation expansion valve 130 to reduce pressure difference, noise generated in the pressure equalization process due to overlarge initial opening degree is avoided, excessive influence on the refrigerant flow during adjustment of the opening degree of the liquid separation expansion valve 130 can be avoided, reliable operation of the integral air conditioner in the pressure equalization process is ensured, and user comfort is improved. Through the reasonable limitation to the preset temperature rise rate, the noise critical value in the pressure equalizing process can be accurately defined, noise influence experience is avoided, and the refrigerant is guaranteed to flow fast to realize pressure equalizing as soon as possible. Meanwhile, by reasonably defining the preset temperature, the pressure equalizing process can be accurately prevented from affecting other heating indoor units 120 which are normally used, and meanwhile, the refrigerant is ensured to flow rapidly so as to realize pressure equalizing as soon as possible.

As described above, in the control method of the simultaneous cooling and heating air conditioner 100 and the simultaneous cooling and heating air conditioner 100 provided in this embodiment, the bypass pipeline 160 is additionally provided at both ends of the original low-pressure electromagnetic valve 150, and the bypass expansion valve 161 is provided on the bypass pipeline 160, so that the cooling/heating function is realized first when the control is actually performed, at least one indoor unit 120 is set to be in a heating mode, the liquid-separating expansion valve 130 and the high-pressure electromagnetic valve 140 of the corresponding pipeline are opened, and the corresponding low-pressure electromagnetic valve 150 and the bypass expansion valve 161 are closed. Then, when one of the indoor units 120 is switched from the heating mode to the cooling mode, the corresponding bypass expansion valve 161 is opened, the refrigerant flows, the internal heat exchange temperature Tn is reduced, and after the difference value between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than a first preset value, the corresponding low-pressure electromagnetic valve 150 is opened, and the corresponding bypass expansion valve 161 is closed; or at least one indoor unit 120 is set to a cooling mode, the liquid separation expansion valve 130 and the low-pressure electromagnetic valve 150 of the corresponding pipelines are opened, and the corresponding high-pressure electromagnetic valve 140 and the bypass expansion valve 161 are closed. When one of the indoor units 120 is switched from the cooling mode to the heating mode, the liquid-separating expansion valve 130 of the corresponding pipeline is opened, the refrigerant flows, the internal heat exchange temperature Tn is increased, and the corresponding high-pressure electromagnetic valve 140 is opened after the difference between the internal heat exchange temperature Tn and the condensing temperature Tw is lower than the second preset value. Finally, the split expansion valve 130 is transitioned to conventional control, thereby completing the mode switch. In this embodiment, the difference between the internal heat exchange temperature Tn and the evaporation temperature Tz or the condensation temperature Tw can represent the corresponding pressure difference, and in the embodiment of the present invention, by reasonably adjusting the internal heat exchange temperature Tn, the high-pressure electromagnetic valve 140 or the high-pressure electromagnetic valve 150 is opened after the internal heat exchange temperature Tn reaches the standard, and because the pressure difference between the two sides of the valve has been reduced to a certain extent, the piping vibration and the flow noise generated in the refrigerant flow process are smaller, and the problem of the prior art that the piping vibration and the noise are larger is effectively solved. Meanwhile, in the mode switching process, the flow speed of the refrigerant is effectively controlled by controlling each valve, so that the noise problem caused in the mode switching process is avoided.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be assessed accordingly to that of the appended claims.

Claims (10)

1. A control method of a simultaneous cooling and heating air conditioner, which is adapted to a simultaneous cooling and heating air conditioner including an outdoor unit (110) and a plurality of indoor units (120) connected simultaneously with the outdoor unit (110), the control method comprising:

setting at least one indoor unit (120) as a heating mode, opening a liquid-separating expansion valve (130) and a high-pressure electromagnetic valve (140) of a corresponding pipeline, and closing a corresponding low-pressure electromagnetic valve (150) and a bypass expansion valve (161), wherein the bypass expansion valve (161) and the low-pressure electromagnetic valve (150) are connected in parallel and bypass through a bypass pipeline (160);

when one of the indoor units (120) is switched from a heating mode to a refrigerating mode, opening the corresponding bypass expansion valve (161) until the difference value between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than a first preset value, opening the low-pressure electromagnetic valve (150) of the corresponding pipeline and closing the corresponding bypass expansion valve (161);

Or, at least one indoor unit (120) is set to be in a refrigeration mode, a liquid separation expansion valve (130) and a low-pressure electromagnetic valve (150) corresponding to the pipelines are opened, and a high-pressure electromagnetic valve (140) and a bypass expansion valve (161) corresponding to the pipelines are closed;

when one of the indoor units (120) is switched from a refrigerating mode to a heating mode, opening the liquid-separating expansion valve (130) of the corresponding pipeline until the difference value between the internal heat exchange temperature Tn and the condensing temperature Tw is lower than a second preset value, and then opening the high-pressure electromagnetic valve (140) of the corresponding pipeline;

and (3) switching the liquid separation expansion valve (130) to conventional control to complete mode switching.

2. The control method of a simultaneous cooling and heating air conditioner according to claim 1, wherein the step of opening the corresponding bypass expansion valve (161) until the difference between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than a first preset value, opening the corresponding low-pressure electromagnetic valve (150) of the corresponding pipeline and closing the corresponding bypass expansion valve (161) comprises:

closing the high-pressure solenoid valve (140) and the liquid-separating expansion valve (130) of the corresponding pipeline;

setting the liquid separation expansion valve (130) of the corresponding pipeline to be a first preset opening degree;

-opening a bypass expansion valve (161) on the corresponding bypass line (160);

Acquiring an internal heat exchange temperature Tn and an evaporation temperature Tz of the indoor unit (120) in a mode switching state;

opening a low-pressure electric valve (150) after the difference between the internal heat exchange temperature Tn and the evaporation temperature Tz is lower than a first preset value;

the corresponding bypass expansion valve (161) is closed.

3. The control method of a simultaneous cooling and warming air conditioner according to claim 2, wherein the step of opening the bypass expansion valve (161) on the corresponding bypass line (160) includes:

gradually opening the bypass expansion valve (161) on the corresponding bypass line (160) according to a preset opening rate to gradually reduce the resistance of the bypass line (160);

when the falling rate of the internal heat exchange temperature Tn exceeds a preset temperature falling rate, maintaining the current opening of the corresponding bypass expansion valve (161) for a preset time.

4. The control method of the simultaneous cooling and heating air conditioner according to claim 3, wherein the first preset opening is 1/5-2/5 of the maximum opening of the liquid-dividing expansion valve (130), and the first preset value is 10 ℃; the preset opening rate is 1/500-1/200 of the maximum opening of the bypass expansion valve (161) per second, the preset temperature drop rate is 0.5 ℃/s, and the preset time is 5s.

5. The control method of a simultaneous cooling and heating air conditioner according to claim 2, wherein the bypass line (160) is a capillary line, and the resistance of the capillary line is greater than a preset resistance so that the rate of decrease of the internal heat exchange temperature Tn is lower than a preset temperature decrease rate.

6. The method for controlling the simultaneous cooling and warming air conditioner according to claim 1, wherein the step of opening the high-pressure solenoid valve (140) of the corresponding line after opening the liquid-separating expansion valve (130) of the corresponding line until the difference between the internal heat exchange temperature Tn and the condensing temperature Tw is lower than a second preset value, comprises:

closing a low-pressure solenoid valve (150) of the corresponding pipeline;

setting the liquid separation expansion valve (130) of the corresponding pipeline to be a second preset opening degree;

acquiring an internal heat exchange temperature Tn and a condensation temperature Tw of the indoor unit (120) in a mode switching state;

and opening the corresponding high-pressure electromagnetic valve (140) when the difference value between the internal heat exchange temperature Tn and the condensation temperature Tw is lower than a second preset value.

7. The method for controlling a simultaneous cooling and heating air conditioner according to claim 6, wherein after the step of acquiring the internal heat exchange temperature Tn and the condensation temperature Tw of the indoor unit (120) in the mode switching state, the method further comprises:

Acquiring heat exchange temperature Tq of the indoor unit (120) in other heating mode states;

and when the rising rate of the internal heat exchange temperature Tn exceeds a preset temperature rising rate and/or the heat exchange temperature Tq of the indoor unit (120) in the state of the other heating modes is lower than a preset temperature, reducing the third preset opening of the corresponding liquid separation expansion valve (130).

8. The control method of the simultaneous cooling and heating air conditioner according to claim 7, wherein the second preset opening is 1/5-2/5 of the maximum opening of the liquid-dividing expansion valve (130); the third preset opening is 1/500-1/200 of the maximum opening of the liquid separation expansion valve (130); the second preset value is 10 ℃; the preset temperature rise rate is 0.5 ℃/s; the preset temperature is 46 ℃.

9. The control method of a simultaneous cooling and warming air conditioner according to claim 6, wherein after the step of setting the liquid-dividing expansion valve (130) of the corresponding line to a second preset opening degree, the control method further comprises:

and stopping the fan of the indoor unit (120) in the mode switching state.

10. A simultaneous cooling and heating air conditioner, adapted to be used as claimed in any one of claims 1 to 9, comprising:

A plurality of indoor units (120);

an outdoor unit (110), wherein the outdoor unit (110) comprises an outdoor heat exchanger (111), a compressor assembly (112), a high-pressure gas collecting pipe (113), a low-pressure gas collecting pipe (114) and a liquid distributing head (115), the liquid distributing head (115) is respectively connected with a plurality of indoor units (120) through a plurality of liquid distributing pipelines (116), and the outdoor heat exchanger (111) is connected with the liquid distributing head (115) through pipelines; the compressor assembly (112) is connected with the outdoor heat exchanger (111) through a pipeline; the high-pressure gas collecting pipe (113) is connected with the compressor assembly (112) through a pipeline and is connected with the indoor units (120) through a plurality of high-pressure gas distribution pipelines (117) respectively; the low-pressure gas collecting pipe (114) is connected with the compressor assembly (112) through a pipeline and is connected with the indoor units (120) through a plurality of low-pressure gas distribution pipelines (118) respectively;

the compressor assembly (112) is used for compressing a refrigerant and adjusting the flow direction of the refrigerant, each liquid separation pipeline (116) is provided with a liquid separation expansion valve (130), each high-pressure gas separation pipeline (117) is provided with a high-pressure electromagnetic valve (140), and the high-pressure electromagnetic valves (140) are used for being conducted in a heating state so that the refrigerant flows from the high-pressure gas collecting head to the corresponding indoor unit (120); each low-pressure gas distribution pipeline (118) is provided with a low-pressure electromagnetic valve (150), the low-pressure electromagnetic valve (150) is used for being conducted in a refrigeration state, so that a refrigerant flows to the low-pressure gas collection pipeline (114) from the corresponding indoor unit (120), two ends of each low-pressure electromagnetic valve (150) are further provided with bypass pipelines (160), the bypass pipelines (160) are provided with bypass expansion valves (161), and the bypass expansion valves (161) are connected with the low-pressure electromagnetic valves (150) in parallel.