WO2021228020A1

WO2021228020A1 - Method for controlling multi-split air conditioning system

Info

Publication number: WO2021228020A1
Application number: PCT/CN2021/092654
Authority: WO
Inventors: 高强; 张铭; 张晓迪; 王海胜; 宋德跃; 周明杰; 许磊; 刁洪福; 张东
Original assignee: 青岛海尔空调电子有限公司; 海尔智家股份有限公司
Priority date: 2020-08-17
Filing date: 2021-05-10
Publication date: 2021-11-18
Also published as: CN112032912A

Abstract

A method for controlling a multi-split air conditioning system, comprising: acquiring an indoor environmental temperature (S101); calculating the difference between the indoor environmental temperature and a set temperature (S103); and selectively controlling the degree of opening of a first electronic expansion valve/a second electronic expansion valve according to the difference, and/or switching a working state of a first four-way valve/a second four-way valve (S105). By controlling the degree of opening of the first electronic expansion valve/the second electronic expansion valve and switching the working state of the first four-way valve/the second four-way valve, a first indoor heat exchanger and a second indoor heat exchanger can be in a same operating state or different operating states, output of the cooling capacity or the heating capacity of an indoor unit is adjusted, and thus the environmental temperature of an indoor space can be adjusted without halting a compressor.

Description

Control method of multi-connected air-conditioning system

Technical field

The invention relates to the technical field of air conditioning, and specifically provides a control method of a multi-connected air conditioning system.

Background technique

With the improvement of people's living standards, the application of multi-connected central air conditioners (commonly known as one-to-multiple air conditioners) has become more and more extensive, that is, one outdoor unit corresponds to multiple indoor units, and one outdoor unit can cool or heat multiple rooms at the same time . However, in the process of cooling or heating, after the central air conditioner runs for a period of time to reach the set temperature, the compressor will be stopped and the indoor unit will stop working, so as to avoid the temperature of the indoor space being too low or too high. The compressor stops for a period of time, and after the indoor space temperature reaches the starting temperature again, restart the compressor, the indoor unit restarts to work, and continues to cool or heat.

However, in the above control method, the indoor ambient temperature will change during the period from compressor shutdown to restart. For example, in the cooling mode, the indoor space will heat up after the compressor is stopped, and in the heating mode, the indoor space will change after the compressor is stopped. Cooling, large temperature fluctuations, and poor user experience. In addition, the frequent start and stop of the compressor is not conducive to the reliable operation of the compressor.

Correspondingly, a new technical solution is needed in this field to solve the above-mentioned problems.

Summary of the invention

In order to solve the above-mentioned problems in the prior art, that is, to solve the problem that the existing multi-unit central air conditioner needs to be started and stopped frequently to maintain the same indoor ambient temperature, the present invention provides a control method of the multi-unit air conditioning system , The multi-unit air conditioning system includes an outdoor unit and at least one indoor unit, and the indoor unit includes a first indoor heat exchanger, a second indoor heat exchanger, a first electronic expansion valve, and a second electronic expansion valve. The machine includes a compressor, a first four-way valve, a second four-way valve, and an outdoor heat exchanger. The outdoor heat exchanger is equipped with an outdoor fan. The first four-way valve has d1, c1, s1, and e1. Four ports, the second four-way valve has four ports d2, c2, s2, and e2, and the first port of the first indoor heat exchanger is in communication with the first port of the first electronic expansion valve, The second interface of the first indoor heat exchanger is connected to the e2 interface of the second four-way valve, and the first interface of the second indoor heat exchanger is connected to the first interface of the second electronic expansion valve The second port of the second indoor heat exchanger is connected to the e1 port of the first four-way valve, and the outlet of the compressor is respectively connected to the d1 port of the first four-way valve and the The d2 interface of the second four-way valve is connected, the inlet of the compressor is respectively connected to the s1 interface of the first four-way valve and the s2 interface of the second four-way valve, and the outdoor heat exchanger The first interface is connected to the c2 interface of the second four-way valve, and the second interface of the outdoor heat exchanger is respectively connected to the second interface of the first electronic expansion valve and the second interface of the second electronic expansion valve. The two interfaces are connected; the c1 interface of the first four-way valve is cut off; the control method includes: obtaining the indoor ambient temperature; calculating the difference between the indoor ambient temperature and the set temperature; according to the difference, Selectively control the opening and closing of the first electronic expansion valve/the second electronic expansion valve, and/or switch the working state of the first four-way valve/the second four-way valve, so as to adjust the Operation status of the first indoor heat exchanger and the second indoor heat exchanger.

In the preferred technical solution of the above control method, "based on the difference, the opening and closing of the first electronic expansion valve/the second electronic expansion valve are selectively controlled, and/or the first four-way valve is switched The step of "valve/the second four-way valve working state" further includes: if the difference is less than a first threshold, controlling the first electronic expansion valve or the second electronic expansion valve to close.

In the preferred technical solution of the above-mentioned control method, the first indoor heat exchanger and the second indoor heat exchanger are arranged in sequence along the air flow direction, and the first indoor heat exchanger is selectively controlled according to the difference. The step of opening and closing the electronic expansion valve/the second electronic expansion valve, and/or switching the working state of the first four-way valve/the second four-way valve" further includes: when the first electronic expansion valve Or when the second electronic expansion valve is in the closed state and the air conditioning system is operating in the cooling mode, if the difference is still less than the first threshold, the first electronic expansion valve and the second electronic expansion are controlled The valves are opened to a certain degree of opening respectively, and the first four-way valve is controlled to switch to the second working state, and the second four-way valve is controlled to switch to the first working state; wherein the first four-way valve of the first four-way valve The second working state is that the d1 interface and e1 interface of the first four-way valve are connected, and the s1 interface and the c1 interface are connected. The first working state of the second four-way valve is d2 of the second four-way valve. The interface is connected to the c2 interface, and the s2 interface is connected to the e2 interface.

In the preferred technical solution of the above control method, "based on the difference, the opening and closing of the first electronic expansion valve/the second electronic expansion valve are selectively controlled, and/or the first four-way valve is switched The step of "valve/the second four-way valve working state" further includes: when the air-conditioning system is operating in the cooling mode, if the difference is greater than the first threshold and less than the second threshold, controlling the first The electronic expansion valve and the second electronic expansion valve are respectively opened to a certain degree of opening, and the first four-way valve and the second four-way valve are controlled to switch to the first working state, and the operation of the compressor is reduced The frequency and/or the rotational speed of the outdoor fan; wherein the first working state of the first four-way valve is that the d1 interface and the c1 interface of the first four-way valve are connected, and the s1 interface and the e1 interface are connected, The first working state of the second four-way valve is that the d2 interface and the c2 interface of the second four-way valve are connected, and the s2 interface and the e2 interface are connected.

In the preferred technical solution of the above-mentioned control method, the first indoor heat exchanger and the second indoor heat exchanger are arranged in sequence along the air flow direction, and the first indoor heat exchanger is selectively controlled according to the difference. The step of opening and closing the electronic expansion valve/the second electronic expansion valve, and/or switching the working state of the first four-way valve/the second four-way valve" further includes: when the first electronic expansion valve Or when the second electronic expansion valve is in the closed state and the air conditioning system is operating in the heating mode, if the difference is still less than the first threshold, the first electronic expansion valve and the second electronic expansion valve are controlled. The expansion valves are opened to a certain degree of opening respectively, and the first four-way valve is controlled to switch to the first working state, and the second four-way valve is controlled to switch to the second working state; wherein, the first four-way valve The first working state is that the d1 interface and the c1 interface of the first four-way valve are connected, and the s1 interface and the e1 interface are connected. The second working state of the second four-way valve is that of the second four-way valve. The d2 interface is connected to the e2 interface, and the s2 interface is connected to the c2 interface.

In the preferred technical solution of the above-mentioned control method, the first indoor heat exchanger and the second indoor heat exchanger are arranged in sequence along the air flow direction, and the first indoor heat exchanger is selectively controlled according to the difference. The step of opening and closing the electronic expansion valve/the second electronic expansion valve, and/or switching the working state of the first four-way valve/the second four-way valve” further includes: when the air conditioning system is running and heating In mode, if the difference is greater than the first threshold and less than the second threshold, the first electronic expansion valve and the second electronic expansion valve are controlled to open to a certain degree of opening respectively, and the first four The two-way valve and the second four-way valve are both switched to the second working state, and the operating frequency of the compressor and/or the rotation speed of the outdoor fan is reduced; wherein, the second work of the first four-way valve The state is that the d1 interface and e1 interface of the first four-way valve are in communication, and the s1 interface and the c1 interface are in communication. The second working state of the second four-way valve is that the d2 interface of the second four-way valve and The e2 interface is connected, and the s2 interface and the c2 interface are connected.

In the preferred technical solution of the above control method, a communication pipeline is provided between the second interface of the first indoor heat exchanger and the second interface of the second indoor heat exchanger, and the communication pipeline is provided with The first electronic control valve, the second interface of the second indoor heat exchanger is also provided with a second electronic control valve, and one end of the communication pipeline is arranged at the second interface of the second indoor heat exchanger and the second interface of the second indoor heat exchanger. Between the second electronic control valve.

In the preferred technical solution of the above control method, "based on the difference, the opening and closing of the first electronic expansion valve/the second electronic expansion valve are selectively controlled, and/or the first four-way valve is switched The step of "valve/the second four-way valve working state" further includes: if the difference is still less than the first threshold, controlling the first electronic control valve to close and the second electronic control valve to open; Otherwise, control at least one of the first electronic control valve to close and the second electronic control valve to open.

In the preferred technical solution of the above control method, the multi-unit air conditioning system includes a first indoor unit and a second indoor unit, and the first indoor unit of the first indoor unit and the second indoor unit exchanges heat And the second indoor heat exchanger are arranged in sequence along the air flow direction, "according to the difference, the opening and closing of the first electronic expansion valve/the second electronic expansion valve is selectively controlled, and /Or the step of switching the working state of the first four-way valve/the second four-way valve" further includes: if the difference of the first indoor unit is still less than the first threshold, and the first indoor unit If the difference between the two indoor units is greater than or equal to the first threshold, the first electronic control valve in the first indoor unit is controlled to close and the second electronic control valve is opened, and at the same time, the control in the second indoor unit is controlled The first electronic control valve is opened and the second electronic control valve is closed.

In the preferred technical solution of the above-mentioned control method, “selectively control the opening and closing of the first electronic expansion valve/the second electronic expansion valve, or switch the first four-way valve/ The step of "the second four-way valve working state" further includes: if the difference is greater than the second threshold and the air conditioning system is operating in a cooling mode, controlling the first electronic expansion valve and the second electronic expansion valve The electronic expansion valve is opened to a certain degree of opening respectively, the first four-way valve and the second four-way valve are controlled to switch to the first working state, and the compressor and the external fan are controlled to be in accordance with the rated frequency and rated frequency. Rotational speed operation; and/or if the difference is greater than the second threshold and the air conditioning system is operating in heating mode, control the first electronic expansion valve and the second electronic expansion valve to open to a certain opening respectively Control the first four-way valve and the second four-way valve to switch to the second working state, and control the compressor and the external fan to operate at a rated frequency and a rated speed; wherein, the first The first working state of the four-way valve is that the d1 interface and the c1 interface of the first four-way valve are connected, and the s1 interface and the e1 interface are connected. The second working state of the first four-way valve is the first four-way valve. The d1 interface and e1 interface of a four-way valve are connected, and the s1 interface and c1 interface are connected. The first working state of the second four-way valve is that the d2 interface and c2 interface of the second four-way valve are connected, The s2 interface and the e2 interface are connected, and the second working state of the second four-way valve is that the d2 interface and the e2 interface of the second four-way valve are connected, and the s2 interface and the c2 interface are connected.

Those skilled in the art can understand that in the new technical solution, the difference between the indoor ambient temperature and the set temperature is calculated, and according to the difference, the first electronic expansion valve/second electronic expansion valve is selectively controlled. The opening degree of the expansion valve and/or switching the working state of the first four-way valve/the second four-way valve can change the refrigerant in the compressor, the first indoor heat exchanger, the second indoor heat exchanger and the outdoor heat exchange The closed loop formed between the compressors, so that the first indoor heat exchanger and the second indoor heat exchanger are in the same or different operating state, adjust the cooling capacity or heating output of the indoor unit, so that the compressor can be stopped without stopping Under the premise, better adjust the ambient temperature of the indoor space.

Specifically, if the difference is less than the first threshold, the first electronic expansion valve or the second electronic expansion valve is controlled to close. In this way, the refrigerant only passes through one of the first indoor heat exchanger and the second indoor heat exchanger, that is, only one indoor heat exchanger exchanges heat with the air in the indoor unit, which can effectively reduce the cooling capacity or The output of heating heat can maintain the indoor constant temperature without stopping the compressor.

Further, the first indoor heat exchanger and the second indoor heat exchanger are arranged in sequence along the air flow direction, and when the first electronic expansion valve or the second electronic expansion valve is in the closed state and the air conditioning system is operating in the cooling mode, if The difference between the indoor ambient temperature and the set temperature is still less than the first threshold, that is, when the indoor ambient temperature is still lower than the set temperature, the first electronic expansion valve and the second electronic expansion valve are controlled to open to a certain degree of opening respectively, and the first electronic expansion valve is controlled to open to a certain degree. The d1 interface and e1 interface of a four-way valve are connected, the s1 interface and the c1 interface are connected, and the d2 interface and c2 interface of the second four-way valve are connected, and the s2 interface and e2 interface are connected, so that the refrigerant is in the first room. The heat exchanger absorbs heat and evaporates, and then releases heat and condenses at the second indoor heat exchanger, so that when the air in the indoor space passes through the first indoor heat exchanger and the second indoor heat exchanger (passing in the opposite direction), the temperature will be lowered first After the temperature rises, the temperature of the air that finally enters the indoor space can be the same as the indoor temperature or slightly higher than the temperature in the normal cooling mode, so that the indoor constant temperature can be maintained or the temperature of the space where the indoor unit is located can be appropriately increased, thereby avoiding the compressor Discomfort caused by frequent start and stop and low indoor ambient temperature in cooling mode.

Further, when the air conditioning system is operating in the cooling mode, if the difference is greater than the first threshold and less than the second threshold, the first electronic expansion valve and the second electronic expansion valve are controlled to open to a certain degree of opening respectively, and the first four-way valve is controlled The d1 interface is connected to the c1 interface, the s1 interface is connected to the e1 interface, the d2 interface of the second four-way valve is connected to the c2 interface, and the s2 interface is connected to the e2 interface. At this time, the operating state of the air conditioning system is normal cooling Mode, and since the indoor environment temperature is close to the set temperature at this time, if you continue to operate in the normal cooling mode, the indoor environment temperature may be too low. You can reduce the air conditioner by reducing the operating frequency of the compressor and/or the speed of the outdoor fan The output of the cooling capacity of the system can prevent the indoor environment temperature from dropping too much and causing discomfort.

Further, when the first electronic expansion valve or the second electronic expansion valve is in the closed state and the air conditioning system is operating in the heating mode, if the difference between the indoor ambient temperature and the set temperature is still less than the first threshold, that is, the indoor ambient temperature is still high When the temperature is set, the first electronic expansion valve and the second electronic expansion valve are controlled to open to a certain degree of opening respectively, and the d1 interface and c1 interface of the first four-way valve are controlled to communicate, and the s1 interface and e1 interface are connected. Control the d2 interface and e2 interface of the second four-way valve to communicate, and the s2 interface and c2 interface to communicate, so that the refrigerant releases heat and condenses at the first indoor heat exchanger, and absorbs heat at the second indoor heat exchanger to evaporate, so When the air in the indoor space passes through the first indoor heat exchanger and the second indoor heat exchanger (passing in the reverse direction), the temperature is first raised and then lowered, and the temperature of the air entering the indoor space can be the same as the indoor temperature or higher than normal heating The temperature in the mode is slightly lower, so that the indoor constant temperature can be maintained or the temperature of the space where the indoor unit is located can be appropriately reduced, so as to avoid the discomfort caused by the frequent start and stop of the compressor and the excessively high indoor ambient temperature in the heating mode.

Further, when the air conditioning system is operating in the heating mode, if the difference between the indoor ambient temperature and the set temperature is greater than the first threshold and less than the second threshold, the first electronic expansion valve and the second electronic expansion valve are controlled to be opened to a certain value. The degree of opening controls the connection between the d1 interface and e1 interface of the first four-way valve, the connection between the s1 interface and the c1 interface, the connection between the d2 interface and the e2 interface of the second four-way valve, and the connection between the s2 interface and the c2 interface. , The operating state of the air conditioning system is the normal heating mode, and since the indoor ambient temperature is close to the set temperature at this time, the operating frequency of the compressor and/or the speed of the outdoor fan is reduced to reduce the heating output of the air conditioning system. Therefore, it is possible to avoid discomfort caused by too much increase in the indoor ambient temperature.

Further, a communication pipeline is provided between the second interface of the first indoor heat exchanger and the second interface of the second indoor heat exchanger, and the first electronic control valve is arranged on the communication pipeline, so that it can be closed by closing the second interface. An electronic control valve prevents the refrigerant from returning to the compressor directly through the first four-way valve, connecting pipeline, and second four-way valve without passing through any heat exchanger after coming out of the compressor. The situation arises. A second electronic control valve is also provided at the second interface of the second indoor heat exchanger, and one end of the communication pipeline is set between the second interface of the second indoor heat exchanger and the second electronic control valve. In this way, The second electronic control valve can be opened or closed according to actual needs, so that the refrigerant forms a different closed loop between the compressor, the outdoor heat exchanger, the first indoor heat exchanger and the second indoor heat exchanger.

Further, if the difference between the indoor ambient temperature and the set temperature is still less than the first threshold, the first electronic control valve is controlled to be closed and the second electronic control valve is opened. In this way, the first indoor heat exchanger and One of the second indoor heat exchangers is used as the evaporator and the other is used as the condenser: in the cooling mode, the temperature of the air coming out of the indoor unit is increased to prevent the indoor environment temperature from being too low; in the heating mode, the heat coming out of the indoor unit is reduced The temperature of the air, so as to avoid the indoor environment temperature is too high. Otherwise, control at least one of the first electronic control valve and the second electronic control valve to open. For example, when the difference between the indoor ambient temperature and the set temperature is greater than the second threshold, the first electronic control valve can be controlled to close, The electric control valve is opened, or the first electric control valve is controlled to open, the second electric control valve is closed, or the first electric control valve and the second electric control valve are opened at the same time, so that the first indoor heat exchanger and the second indoor The heat exchangers are in the same working state, so that the indoor ambient temperature can be better adjusted.

Preferably, the multi-unit air conditioning system includes a first indoor unit and a second indoor unit. The first indoor heat exchanger and the second indoor heat exchanger of the two indoor units are arranged in sequence along the air flow direction. The difference between the indoor ambient temperature of an indoor unit and the set temperature is still less than the first threshold, and the difference between the indoor ambient temperature of the second indoor unit and the set temperature is greater than or equal to the first threshold, then the first indoor unit is controlled The first electronic control valve is closed and the second electronic control valve is opened. At the same time, the first electronic control valve in the second indoor unit is controlled to open and the second electronic control valve is closed, so that the operating status of the first indoor unit and the second indoor unit It is also different, so that one of the first indoor heat exchanger and the second indoor heat exchanger in the first indoor unit is used as a condenser and the other is used as an evaporator, and the first indoor heat exchanger in the second indoor unit exchanges heat The heat exchanger and the second indoor heat exchanger still serve as evaporators or condensers at the same time. In this way, the ambient temperatures that can be reached in the indoor spaces where the two indoor units are located are also different, so that the different requirements of users in the indoor spaces where the different indoor units are located can be met without stopping the compressor.

Further, if the difference between the indoor ambient temperature and the set temperature is greater than the second threshold, it means that the indoor ambient temperature is significantly different from the set temperature, and it is far from reaching the expected target. At this time, the first electronic expansion valve and The second electronic expansion valve is opened to a certain degree of opening, and the compressor and the outdoor fan are controlled to operate at the rated frequency and rated speed. In the cooling mode, the d1 port and the c1 port of the first four-way valve are connected, and the s1 port and e1 are connected. The interface is connected, and the d2 interface and c2 interface of the second four-way valve are connected, and the s2 interface and e2 interface are connected; in heating mode, the d1 interface and e1 interface of the first four-way valve are connected, and the s1 interface and The c1 interface is connected, the d2 interface and the e2 interface of the second four-way valve are connected, and the s2 interface and the c2 interface are connected. Through this setting method, the air conditioning system is in the normal cooling or heating mode, so that the indoor environment temperature can reach the set temperature as soon as possible, and the user experience can be improved.

Description of the drawings

Hereinafter, the control method of the air conditioner of the present invention will be described with reference to the drawings. In the attached picture:

Fig. 1 is a first schematic diagram of a flow in a refrigeration mode of a multi-unit air conditioning system according to an embodiment of the present invention;

Fig. 2 is a first schematic diagram of a flow in a heating mode of a multi-unit air conditioning system according to an embodiment of the present invention;

FIG. 3 is a second schematic diagram of a flow in a refrigeration mode of a multi-unit air conditioning system according to an embodiment of the present invention;

4 is a second schematic diagram of the flow in the heating mode of the multi-unit air conditioning system according to an embodiment of the present invention;

Fig. 5 is a first flowchart of a control method of a multi-connected air-conditioning system according to an embodiment of the present invention;

Fig. 6 is a second flowchart of a control method of a multi-connected air conditioning system according to an embodiment of the present invention;

FIG. 7 is a third flowchart of a control method of a multi-connected air-conditioning system according to an embodiment of the present invention;

FIG. 8 is a fourth flowchart of a control method of a multi-connected air-conditioning system according to an embodiment of the present invention;

Fig. 9 is a fifth flowchart of a control method of a multi-unit air conditioning system according to an embodiment of the present invention.

List of reference signs:

1. Compressor; 2. Gas-liquid separator; 3. Outdoor heat exchanger; 4. Economizer; 5. First four-way valve; 6. Second four-way valve; 7. Third electronic expansion valve; 8. Fourth electronic expansion valve; 9, pressure regulating valve; 101, the first indoor heat exchanger of the first indoor unit; 102, the first indoor heat exchanger of the second indoor unit; 111, the second indoor unit of the first indoor unit Heat exchanger; 112, the second indoor heat exchanger of the second indoor unit; 121, the first electronic expansion valve of the first indoor unit; 122, the first electronic expansion valve of the second indoor unit; 131, the first indoor unit 132, the second electronic expansion valve of the second indoor unit; 141, the communication pipeline of the first indoor unit; 142, the communication pipeline of the second indoor unit; 151, the first indoor unit An electric control valve; 152. The first electric control valve of the second indoor unit; 161. The second electric control valve of the first indoor unit; 162. The second electric control valve of the first indoor unit; 17. Liquid pipe stop valve ; 18. The first trachea stop valve; 19, the second trachea stop valve; 20, the capillary tube.

Detailed ways

The preferred embodiments of the present invention will be described below with reference to the drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention, and are not intended to limit the protection scope of the present invention.

It should be noted that in the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The term of the indicated direction or positional relationship is based on the direction or positional relationship shown in the drawings, which is only for ease of description, and does not indicate or imply that the device or element must have a specific orientation, be configured and operated in a specific orientation Therefore, it cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance.

1 to 4, the multi-unit air conditioning system of the present application will be introduced. 1 is a schematic diagram 1 of the flow in the refrigeration mode of a multi-unit air conditioning system according to an embodiment of the present invention, and Figure 2 is a schematic diagram 1 of the flow in the heating mode of a multi-unit air conditioning system according to an embodiment of the present invention. 3 is the second schematic diagram of the flow in the refrigeration mode of the multi-unit air conditioning system according to an embodiment of the present invention, and FIG. 4 is the second schematic diagram of the process in the heating mode of the multi-unit air conditioning system according to an embodiment of the present invention.

As shown in Figure 1-4, the multi-unit air conditioning system includes an outdoor unit, a first indoor unit, and a second indoor unit. Both the first indoor unit and the second indoor unit include first

indoor heat exchangers

101 and 102, and a second indoor unit.

Indoor heat exchanger

111, 112, first

electronic expansion valve

121, 122, and second

electronic expansion valve

131, 132, outdoor unit includes compressor 1, first four-way valve 5, second four-way valve 6 and outdoor Heater 3. The first four-way valve 5 has four ports d1, c1, s1, and e1. The second four-way valve 6 has four ports d2, c2, s2, and e2. The first ports of the first

electronic expansion valves

121, 122 are connected, the second ports of the first

indoor heat exchangers

101, 102 are connected with the e2 port of the second four-way valve 6, and the second

indoor heat exchangers

111, 112 are connected. The first interface is connected with the first interface of the second

electronic expansion valve

131, 132, the second interface of the second

indoor heat exchanger

111, 112 is connected with the e1 interface of the first four-way valve 5, the compressor 1 The outlet is respectively connected with the d1 interface of the first four-way valve 5 and the d2 interface of the second four-way valve 6, and the inlet of the compressor 1 is respectively connected with the s1 interface of the first four-way valve 5 and the s2 interface of the second four-way valve 6 The first port of the outdoor heat exchanger 3 is connected to the c2 port of the second four-way valve 6, and the second port of the outdoor heat exchanger 3 is connected to the second port and the second port of the first

electronic expansion valve

121, 122, respectively. The second interfaces of the second

electronic expansion valves

131 and 132 are connected, and the c1 interface of the first four-way valve 5 is cut off.

It should be noted that in this embodiment, the first indoor unit and the second indoor unit are arranged in the same manner. For ease of presentation, except for special instructions, the following uses the specific structure of the first indoor unit as an example to illustrate the present invention. Of possible implementations.

In addition, although the specific composition of the air-conditioning system is described above, this is not restrictive, and those skilled in the art can add or delete some components on the basis of this, so that this application is suitable for more specific application scenarios. For example, the air conditioning system of the present application includes at least a compressor, a first four-way valve, a second four-way valve, an outdoor heat exchanger, a first electronic expansion valve, a second electronic expansion valve, a first outdoor heat exchanger, and a second On the basis of the second outdoor heat exchanger, one or more of the other components can be omitted, and such a change does not affect the implementation of the subsequent control method of this application.

In this embodiment, as shown in Figures 1 to 4, the first

indoor heat exchangers

101, 102 and the second

indoor heat exchangers

111, 112 are arranged along the air flow direction in the indoor unit, so that the first indoor The air in the second indoor unit and the second indoor unit can exchange heat successively with the first

indoor heat exchanger

101, 102 and the second

indoor heat exchanger

111, 112. For example, taking the first indoor unit as an example, in the cooling mode, the refrigerant When the first indoor heat exchanger 101 and the second indoor heat exchanger 111 both absorb heat and evaporate, the air in the indoor unit will interact with the first indoor heat exchanger 101 and the second indoor heat exchanger 111 successively. Enter the indoor space after gradually cooling down, so that the indoor ambient temperature can be quickly reduced. For another example, in the cooling mode, the refrigerant absorbs heat and evaporates at the first indoor heat exchanger 101, and dissipates heat and condenses at the second indoor heat exchanger 111. Then the air in the indoor unit first interacts with the first indoor heat exchanger 101. After the heat exchange, the temperature is lowered, and then the temperature is increased with the second indoor heat exchanger 111, so that the temperature of the air obtained is higher than that of the first indoor heat exchanger 101 and the second indoor heat exchanger 111 in the cooling mode where both absorb heat and evaporate The temperature of the obtained air is higher, which can reduce the indoor environment temperature without making the indoor environment temperature too low, so that the temperature of the indoor space can be better adjusted. Obviously, the air in the indoor unit can also flow through the second indoor heat exchanger 111 and the first indoor heat exchanger 101 to change the temperature.

1 to 4, a connecting pipe 141 is provided between the second interface of the first indoor heat exchanger 101 and the second interface of the second indoor heat exchanger 111, and a first connection pipe 141 is provided on the connecting pipe 141. The electric control valve 151 is further provided with a second electric control valve 161 at the second interface of the second indoor heat exchanger 111, and one end of the communication pipe 141 is arranged at the second interface of the second indoor heat exchanger 111 and the second interface. Between the electronic control valve 161.

In this way, the opening or closing of the first electronic control valve 151 and the second electronic control valve 161 can be controlled according to actual needs, so that the refrigerant flows in the compressor 1, the outdoor heat exchanger 3, the first indoor heat exchanger 101, and the second electronic control valve. Different closed loops are formed between the two indoor heat exchangers 111. For example, in the refrigeration mode, the first electronic control valve 151 is closed and the second electronic control valve 161 is opened. After the refrigerant comes out of the compressor 1, it passes through the d2 and c2 ports of the second four-way valve 6 in sequence to exchange outdoor heat. Reactor 3, the first indoor heat exchanger 101, the e2 interface and s2 interface of the second four-way valve 6 return to the compressor 1, and the other way passes through the d2 interface and c2 interface of the second four-way valve 6 in turn, and the outdoor heat exchanger 3. The second indoor heat exchanger 111, the e1 interface and the s1 interface of the first four-way valve 5 return to the compressor 1. For another example, in the refrigeration mode, the first electronic control valve 151 is opened and the second electronic control valve 161 is closed. 3 Reach the indoor unit, and then enter the first indoor heat exchanger 101 and the second indoor heat exchanger 111 to exchange heat with the air in the indoor space, and merge after coming out of the first indoor heat exchanger 101 and the second indoor heat exchanger 111 , And then return to compressor 1 via the e2 interface and s2 interface of the second four-way valve 6. Obviously, the above-mentioned opening and closing methods of the first electronic control valve 151 and the second electronic control valve 161 are also applicable to the heating mode. Obviously, both the first electronic control valve 151 and the second electronic control valve 161 can also be closed, and those skilled in the art can flexibly choose according to specific application scenarios.

Continuing to refer to Figures 1 to 4, the outdoor unit also includes an economizer 4, a third electronic expansion valve 7, a fourth electronic expansion valve 8, a pressure regulating valve 9 and a gas-liquid separator 2. The first interface of the economizer 4 is connected to the second The second interface of an electronic expansion valve 121 is connected to the second interface of the second electronic expansion valve 131, and the second interface of the economizer 4 is connected to the first interface of the third electronic expansion valve 7 and the fourth electronic expansion valve 8 respectively. The second port is connected, the third port of the economizer 4 is connected with the second port of the third electronic expansion valve 7, and the fourth port of the economizer 4 is connected with the inlet of the gas-liquid separator 2. When the refrigerant from the heater 3 reaches the economizer 4, a small part of it will flow out. This part of the refrigerant enters the economizer 4 through the third electronic expansion valve 7 and the third interface of the economizer 4, and then passes through the economizer 4. The fourth port flows back to the gas-liquid separator 2, or, after the refrigerant from the indoor unit reaches the economizer 4, the refrigerant from the second port of the economizer 4 will also flow out a small part. It will also enter the economizer 4 through the third electronic expansion valve 7 and the third port of the economizer 4, and then flow back to the gas-liquid separator 2 from the fourth port of the economizer 4. This small part of the refrigerant exchanges heat with another part of the refrigerant flowing through the first interface of the economizer 4 and the second interface of the economizer 4 in the economizer 4, thereby achieving the purpose of heat recovery and energy saving.

Continuing to refer to Figures 1 to 4, the inlet of the gas-liquid separator 2 is respectively connected with the fourth port of the economizer 4, the s2 port of the second four-way valve 6 and the s1 port of the first four-way valve 5, and the gas-liquid separation The outlet of the compressor 2 is connected to the inlet of the compressor 1, so that the refrigerant returning from the various pipelines to the gas-liquid separator 2 will be separated in the gas-liquid separator 2, and the liquid refrigerant is deposited in the gas-liquid separator 2. , Only the gaseous refrigerant will enter the compressor 1 and be compressed again, thereby avoiding the occurrence of problems such as liquid hammer caused by the liquid refrigerant entering the compressor 1. Obviously, the gas-liquid separator 2 may not be installed, or equipment such as filters may be installed, and the refrigerants of each path are filtered and then returned to the compressor 1 to be compressed again.

1 to 4, the first interface of the fourth electronic expansion valve 8 is connected to the second interface of the outdoor heat exchanger 3, and the second interface of the fourth electronic expansion valve 8 is respectively connected to the second interface of the economizer 4 Connected to the first interface of the third electronic expansion valve 7, and the pressure regulating valve 9 is arranged in parallel with the fourth electronic expansion valve 8. Through this arrangement, the fourth electronic expansion valve 8 and/or the pressure regulating valve can also be passed through 9 to adjust the pressure of the refrigerant between the outdoor heat exchanger 3 and the economizer 4, even if one of the pressure regulating valve 9 and the fourth electronic expansion valve 8 fails, the outdoor heat exchanger 3 and the economizer 4 can be adjusted. The pressure of the refrigerant between. Obviously, the pressure regulating valve 9 can also be omitted, and the pressure of the refrigerant between the outdoor heat exchanger 3 and the economizer 4 can be adjusted only through the fourth electronic expansion valve 8. If the fourth electronic expansion valve 8 fails, it can also be used The first electronic expansion valve 121 and the second electronic expansion valve 131 adjust the pressure of the refrigerant when circulating between the indoor unit and the outdoor unit, so as to ensure the normal operation of the multi-line air conditioning system.

Continuing to refer to Figures 1 to 4, the outdoor unit also includes a liquid pipe shut-off valve 17, a first gas pipe shut-off valve 18, and a second gas pipe shut-off valve 19. The liquid pipe shut-off valve 17 is arranged at the first interface of the economizer 4 and the room Between the machines, the first tracheal cut-off valve 18 is arranged between the e1 port of the first four-way valve 5 and the indoor unit, and the second tracheal cut-off valve 19 is provided between the e2 interface of the second four-way valve 6 and the indoor unit, In this way, during the normal operation of the multi-unit air conditioning system, if one of the above-mentioned pipelines fails, the liquid pipe stop valve 17, the first air pipe stop valve 18, and the second air pipe stop valve 19 set on the pipeline can be closed. , Thereby closing the circuit of the refrigerant, which can prevent the problem of refrigerant leakage during the overhaul.

In this embodiment, as shown in Figures 1 to 4, the outdoor unit further includes a capillary tube 20. The c1 port of the four-way valve 5 is cut off, and the refrigerant cannot flow out through the c1 port of the first four-way valve 5. Obviously, it is also possible to cut off the c1 interface of the first four-way valve 5 by arranging a cutoff valve between the s1 interface and the c1 interface of the first four-way valve 5. Those skilled in the art can flexibly choose according to specific application requirements. .

The following describes possible implementations of the control method of the present invention with reference to the accompanying drawings.

Fig. 5 is a schematic flow chart 1 of a control method of a multi-unit air conditioning system according to an embodiment of the present invention. As shown in Fig. 5, the control method for the above-mentioned multi-unit air conditioning system includes:

Step S101: Obtain the indoor ambient temperature (Tin);

Step S103: Calculate the difference between the indoor ambient temperature (Tin) and the set temperature (Ts);

Step S105: According to the difference, selectively control the opening and closing of the first electronic expansion valve/the second electronic expansion valve, and/or switch the working state of the first four-way valve/the second four-way valve.

Through the above setting method, according to the difference between the indoor ambient temperature and the set temperature, the first

electronic expansion valve

121, 122 and/or the second

electronic expansion valve

131, 132 are selectively opened and closed, and/or the first and fourth electronic expansion valves are switched. The working status of the two-way valve 5 and the second four-way valve 6 can be changed in the compressor 1, the first

indoor heat exchanger

101, 102, the second

indoor heat exchanger

111, 112, and the outdoor heat exchanger 3. The closed loop formed between the first

indoor heat exchanger

101, 102 and the second

indoor heat exchanger

111, 112 are in the same or different operating states, so as to adjust the cooling capacity or heating output of the indoor unit, thereby enabling more Adjust the ambient temperature of the indoor space well.

For example, in the cooling mode, if the indoor ambient temperature is lower than the set temperature, it means that the indoor ambient temperature is too low at this time, so it is necessary to reduce the output of the cooling capacity and increase the temperature of the indoor space appropriately. You can turn off the first electronic One of the

expansion valves

121 and 122 and the second

electronic expansion valve

131 and 132 reduces the output of the refrigeration capacity and appropriately increases the indoor ambient temperature. If after a period of time, the indoor ambient temperature is still lower than the set temperature, you can also open the closed expansion valve, and further switch the working state of the first four-way valve 5 and the second four-way valve 6, change the first indoor The working status of the

heat exchangers

101, 102 and the second

indoor heat exchangers

111, 112, such as the first

indoor heat exchanger

101, 102 and the second

indoor heat exchanger

111, 112 as a condenser and the other as an evaporator , To further increase the indoor ambient temperature and improve user experience. Obviously, when the indoor ambient temperature is lower than the set temperature, the first

electronic expansion valve

121, 122 and the second

electronic expansion valve

131, 132 may not be adjusted, and the first four-way valve 5 and the second four-way valve 6 can be switched directly. Working status.

It should be noted that in the present invention, the calculation method of the difference between the indoor ambient temperature (Tin) and the set temperature (Ts) is related to the operation mode of the air conditioning system. For example, in the cooling mode, the difference between the two is The indoor ambient temperature (Tin) minus the set temperature (Ts), another example, in the heating mode, the difference between the two is the set temperature (Ts) minus the indoor ambient temperature (Tin).

The control method of the multi-connected air conditioning system of the present application will be described in detail below.

First of all, it should be noted that in the following embodiments of the present invention, the first threshold value is 0°C, and the second threshold value is 2°C. However, it is obvious that the first threshold value and the second threshold value may also be Other values, such as the first threshold value is 0.5°C, 1°C or even -0.5°C, and the second threshold value is 3°C or 4°C. Those skilled in the art can flexibly choose the specific values of the first threshold and the second threshold according to actual experience. Value.

Referring to FIG. 6, FIG. 6 is a second flowchart of a control method of a multi-unit air conditioning system according to an embodiment of the present invention. As shown in Figure 6, the control method of the multi-connected air conditioning system includes:

Step S201: Obtain the indoor ambient temperature (Tin) in the cooling mode;

Step S202: Calculate the difference between the indoor ambient temperature (Tin) and the set temperature (Ts), if Tin-Ts<0°C, execute step S203;

Step S203: Close the first electronic expansion valve or the second electronic expansion valve;

Step S204: recalculate the difference between the indoor ambient temperature (Tin) and the set temperature (Ts), if Tin-Ts<0°C, then execute step S205;

Step S205: controlling the first electronic expansion valve and the second electronic expansion valve to respectively open to a certain degree of opening, and controlling the first four-way valve to switch to the second working state, and controlling the second four-way valve to switch to the first working state;

Step S206: Control the first electronic control valve of the first indoor unit to be closed, the second electronic control valve to open, and the first electronic control valve of the second indoor unit to open and the second electronic control valve to close.

Wherein, in this application, the second working state of the first four-way valve is that the d1 interface and e1 interface of the first four-way valve are connected, the s1 interface and the c1 interface are connected, and the first working state of the first four-way valve is The d1 interface and c1 interface of the first four-way valve are connected, and the s1 interface and e1 interface are connected. The first working state of the second four-way valve is that the d2 interface and c2 interface of the second four-way valve are connected, and the s2 interface is connected. Connected with the e2 interface, the second working state of the second four-way valve is that the d2 interface and the e2 interface of the second four-way valve are connected, and the s2 interface and the c2 interface are connected.

Through the above setting method, as shown in Figure 3, when the first indoor unit and the second indoor unit are both in the cooling mode, if the indoor ambient temperature (Tin)-the set temperature (Ts) <0°C, then first Close the first

electronic expansion valve

121, 122 or the second

electronic expansion valve

131, 132, so that the first indoor unit and the second indoor unit only have the first

indoor heat exchanger

101, 102 and the second indoor heat exchanger 111, One of the 112 is used as an evaporator to reduce the indoor ambient temperature, so that the cooling capacity output to the corresponding indoor space through the first indoor unit and the second indoor unit will be reduced, and the indoor ambient temperature of the corresponding indoor space will be correspondingly Increase appropriately. After this state continues for a period of time, if Tin-Ts is still less than 0°C, then the first

electronic expansion valve

121, 122 and the second

electronic expansion valve

131, 132 are controlled to open to a certain degree of opening, and then the first four-way valve Switch to the second working state, that is, the d1 interface and e1 interface of the first four-way valve are connected, and the s1 interface and c1 interface are connected, and the second four-way valve is switched to the first working state, that is, the second four-way valve The d2 interface is connected to the c2 interface, and the s2 interface is connected to the e2 interface. In addition, the first

electronic expansion valve

121, 122 is opened to a certain degree of opening, and the second

electronic expansion valve

131, 132 is fully opened, turning on the first indoor unit and The second

electronic control valves

161 and 162 of the second indoor unit close the first

electronic control valves

151 and 152 of the first indoor unit and the second indoor unit, and the fourth electronic expansion valve 8 is fully opened. Both the first indoor unit and the second indoor unit are adjusted in the same way. Taking the first indoor unit as an example, the high-temperature and high-pressure gaseous refrigerant from compressor 1 is divided into two paths. The first high-temperature and high-pressure gaseous refrigerant passes through the second four-way valve. The d2 interface and c2 interface of 6 reach the outdoor heat exchanger 3. After the heat is released and condensed at the outdoor heat exchanger 3, the obtained high temperature and high pressure liquid refrigerant is divided into the second interface of the economizer 4 after passing through the fourth electronic expansion valve 8. Two routes: one route of high temperature and high pressure liquid refrigerant is throttled and depressurized by the third electronic expansion valve 7 to become low temperature and low pressure liquid refrigerant to the third interface of the economizer 4, from the third interface to the economizer 4, and from the economy The first port of the device 4 enters the high temperature and high pressure liquid refrigerant of the economizer 4 to obtain low temperature and low pressure gaseous refrigerant after heat exchange, and then exits from the fourth port, and then returns to the gas-liquid separator 2; the other high temperature and high pressure liquid refrigerant is from the economizer 4 The second port of the economizer 4 enters the economizer 4, exchanges heat with another low-temperature and low-pressure liquid refrigerant in the economizer 4, and then achieves a preliminary cooling. After exiting the first port of the economizer 4, it reaches the second electronic expansion valve 131. The second high-temperature and high-pressure gaseous refrigerant from the compressor 1 reaches the second electric control valve 161 through the d1 and e1 ports of the first four-way valve 5, and enters the second indoor heat exchanger 111 through the second electric control valve 161 , The high temperature and high pressure gaseous refrigerant refrigerant releases heat and condenses in the second indoor heat exchanger 111 to obtain high temperature and high pressure liquid refrigerant. The high temperature and high pressure liquid refrigerant from the second indoor heat exchanger 111 passes through the second electronic expansion valve 131 and then reaches the first way The high temperature and high pressure liquid refrigerant at the second electronic expansion valve 131 is mixed. The mixed high-temperature and high-pressure liquid refrigerant is throttled and depressurized by the first electronic expansion valve 121 and then becomes a low-temperature and low-pressure liquid refrigerant and enters the first indoor heat exchanger 101. The low-temperature and low-pressure liquid refrigerant absorbs heat and evaporates in the first indoor heat exchanger 101. The low-temperature and low-pressure gaseous refrigerant is obtained, and the low-temperature and low-pressure gaseous refrigerant from the heat exchanger of the first indoor heat exchanger 101 returns to the gas-liquid separator 2 through the e2 interface and the s2 interface of the second four-way valve 6. In this way, the refrigerant absorbs heat and evaporates at the first

indoor heat exchangers

101 and 102 in the first indoor unit and the second indoor unit, and releases heat and condenses at the second

indoor heat exchangers

111 and 112. The air in the first indoor unit and the second indoor unit is first cooled at the first

indoor heat exchanger

101 and 102, and then heated at the second

indoor heat exchanger

111, 112. In this way, from the first indoor unit and the second indoor unit The temperature of the air entering the indoor space of the indoor unit can be the same as the indoor environment temperature or slightly higher than the temperature in the normal cooling mode, so that the indoor constant temperature can be maintained or the indoor space temperature of the first indoor unit and the second indoor unit can be appropriately increased. Therefore, it is possible to avoid the discomfort caused by the frequent start and stop of the compressor and the low indoor ambient temperature in the cooling mode.

Further, if the users of the indoor space where the first indoor unit and the second indoor unit are located have different requirements for the indoor environment temperature, for example, the user of the indoor space where the user in the first indoor unit is located wants the indoor environment temperature not to continue. Decrease (or it can be understood that the difference between the indoor ambient temperature of the indoor space where the first indoor unit is located and the set temperature Tin-Ts is less than 0°C), the user of the indoor space where the second indoor unit is located wants a lower indoor environment temperature ( Or it can be understood that the difference between the indoor ambient temperature of the indoor space where the second indoor unit is located and the set temperature Tin-Ts is greater than or equal to 0°C), so that the first indoor heat exchanger 101 of the first indoor unit can be One of the second indoor heat exchangers 111 is transformed into a condenser, the other is still used as an evaporator, and both the first indoor heat exchanger 102 and the second indoor heat exchanger 112 of the second indoor unit still serve as evaporators. Specifically, step S206 is executed while step S205 is executed, the d1 interface of the first four-way valve 5 is connected to the e1 interface, the c1 interface is connected to the s1 interface, and the d2 interface of the second four-way valve 6 is connected to the c2 interface, and the e2 interface and s2 are connected. The interface is connected, the first electronic expansion valve 121 in the first indoor unit is opened to a certain angle, the second electronic expansion valve 131 is fully opened, and the first electronic expansion valve 122 and the second electronic expansion valve 132 in the second indoor unit are both Open to a certain degree of opening, close the first electric control valve 151 of the first indoor unit, open the second electric control valve 161 of the first indoor unit, open the first electric control valve 152 of the second indoor unit, and close the second indoor unit The second electronic control valve 162 and the fourth electronic expansion valve 8 of the engine are fully opened. In this way, the high-temperature and high-pressure refrigerant from the compressor 1 can enter the second indoor heat exchanger 111 of the first indoor unit through the d1 and e1 ports of the first four-way valve 4, but cannot enter the second indoor of the second indoor unit.热热器112。 Heat exchanger 112. Specifically, the high-temperature and high-pressure gaseous refrigerant from the compressor 1 is divided into two paths. The first high-temperature and high-pressure gaseous refrigerant reaches the outdoor heat exchanger 3 through the d2 and c2 ports of the second four-way valve 6, and exchanges heat outdoors. The high-temperature and high-pressure liquid refrigerant is obtained after exothermic condensation at the device 3, and the obtained high-temperature and high-pressure liquid refrigerant passes through the fourth electronic expansion valve 8 and is divided into two paths at the second interface of the economizer 4: one high-temperature and high-pressure liquid refrigerant is expanded by the third electron After the throttling and depressurization of the valve 7 becomes a low temperature and low pressure liquid refrigerant, it reaches the third port of the economizer 4, and then enters the economizer 4 from the third port, and enters the high temperature and high pressure of the economizer 4 from the first port of the economizer 4 The liquid refrigerant obtains low-temperature and low-pressure gaseous refrigerant after heat exchange, and then comes out of the fourth interface, and then returns to the gas-liquid separator 2; another high-temperature and high-pressure liquid refrigerant enters the economizer 4 from the second interface of the economizer 4, The other low-temperature and low-pressure liquid refrigerant in the device 4 realizes a preliminary cooling after heat exchange. After exiting the first interface of the economizer 4, it reaches the second electronic expansion valve 131 of the first indoor unit and the first indoor unit of the second indoor unit. At the electronic expansion valve 122 and the second electronic expansion valve 132; the second high-temperature and high-pressure gaseous refrigerant from the compressor 1 reaches the second electronic control valve of the first indoor unit through the d1 and e1 ports of the first four-way valve 5 161 and the second electronic control valve 162 of the second indoor unit.

Next, separately describe the flow path of the refrigerant in the first indoor unit and the second indoor unit. The flow path of the refrigerant in the first indoor unit is: the second high-temperature and high-pressure gaseous refrigerant from the compressor 1 passes through the first indoor unit The second electronic control valve 161 of the first indoor unit enters the second indoor heat exchanger 111 of the first indoor unit, and the high-temperature and high-pressure gaseous refrigerant releases heat and condenses in the second indoor heat exchanger 111 of the first indoor unit to obtain a high-temperature and high-pressure liquid refrigerant. The high-temperature and high-pressure liquid refrigerant from the second indoor heat exchanger 111 of an indoor unit passes through the second electronic expansion valve 131 of the first indoor unit and then mixes with the first path of liquid refrigerant. The mixed liquid refrigerant enters the first indoor heat exchanger 101 of the first indoor unit after being throttled and depressurized by the first electronic expansion valve 121 of the first indoor unit, and the liquid refrigerant exchanges heat in the first indoor unit of the first indoor unit The device 101 absorbs heat and evaporates to obtain a low-temperature and low-pressure gaseous refrigerant. That is, the refrigerant absorbs heat and evaporates in the first indoor heat exchanger 101 of the first indoor unit, and releases heat and condenses in the second indoor heat exchanger 111. The air in the first indoor unit is cooled at the first indoor heat exchanger 101. Heat is generated at the second indoor heat exchanger 111. In this way, the total amount of cooling output from the first indoor unit is reduced compared to before, so that the temperature of the indoor space where the first indoor unit is located can be appropriately increased.

The flow path of the refrigerant in the second indoor unit is: the liquid refrigerant enters the second indoor unit after being throttled and decompressed by the first electronic expansion valve 122 of the second indoor unit and the second electronic expansion valve 132 of the second indoor unit. The first indoor heat exchanger 102 of the second indoor unit and the second indoor heat exchanger 112 of the second indoor unit, the refrigerant is absorbed in the first indoor heat exchanger 102 of the second indoor unit and the second indoor heat exchanger 112 of the second indoor unit Thermal evaporation obtains low-temperature and low-pressure gaseous refrigerant. That is, the refrigerant absorbs heat and evaporates at the first indoor heat exchanger 102 of the second indoor unit and the second indoor heat exchanger 112 of the second indoor unit. The indoor heat exchanger 102 exchanges heat with the second indoor heat exchanger 112 of the second indoor unit.

The low-temperature and low-pressure gaseous refrigerant from the second indoor heat exchanger 112 of the second indoor unit passes through the communication pipeline 142 and the first electronic control valve 152 of the second indoor unit, and then connects with the first indoor heat exchanger of the second indoor unit. The low-temperature and low-pressure gaseous refrigerant from 102 merges, and the combined low-temperature and low-pressure gaseous refrigerant merges with the low-temperature and low-pressure gaseous refrigerant from the first indoor heat exchanger of the first indoor unit 101 heat exchanger again, and then passes through the second four-way valve together. The e2 interface and s2 interface of 6 return to the gas-liquid separator 2.

Through this arrangement, the air in the first indoor unit exchanges heat and cools at the first indoor heat exchanger 101 of the first indoor unit, and exchanges heat and heats at the second indoor heat exchanger 111 of the first indoor unit. The air in the second indoor unit exchanges heat and cools at the first indoor heat exchanger 102 of the second indoor unit and the second indoor heat exchanger 112 of the second indoor unit, so that the first indoor unit and the second indoor unit also They are respectively in different cooling operation modes, so that the different requirements of users in the indoor space where the first indoor unit and the second indoor unit are located can be met without the compressor stopping.

Next, referring to FIG. 7, FIG. 7 is a third flowchart of a control method of a multi-unit air conditioning system according to an embodiment of the present invention. As shown in Figure 7, the control method of the multi-connected air conditioning system includes:

Step S301: Obtain the indoor ambient temperature (Tin) in the cooling mode;

Step S302: Calculate the difference between the indoor ambient temperature (Tin) and the set temperature (Ts): if 0°C≤Tin-Ts≤2°C, go to step S303; if Tin-Ts>2°C, go to step S304;

Step S303: Control the first electronic expansion valve and the second electronic expansion valve to open to a certain degree of opening respectively, and control both the first four-way valve and the second four-way valve to switch to the first working state, reducing the operating frequency of the compressor and /Or the speed of the outdoor fan;

Step S304: The compressor and the outdoor fan are operated at the rated frequency and the rated speed, the first electronic expansion valve and the second electronic expansion valve are controlled to open to a certain degree of opening respectively, and the first four-way valve and the second four-way valve are controlled to switch To the first working state.

Through the above setting method, as shown in Figure 1, when the first indoor unit and the second indoor unit are both in the cooling mode, if Tin-Ts>2°C, it means that the indoor ambient temperature has not reached the set temperature. If you need to continue to cool down, then control the first

electronic expansion valve

121, 122 and the second

electronic expansion valve

131, 132 to open to a certain degree of opening respectively, and control the d1 interface and the c1 interface of the first four-way valve 5 to communicate, s1 The port is connected to the e1 port, the d2 port of the second four-way valve 6 is connected to the c2 port, the s2 port is connected to the e2 port, and the air conditioning system operates in the normal cooling mode. The

electronic expansion valves

121, 122 and the second

electronic expansion valves

131, 132 are all opened to a certain degree of opening, the first

electronic control valves

151, 152 of the first indoor unit and the second indoor unit are both closed, and the first indoor unit and the second indoor unit are closed. The second

electronic control valves

161 and 162 of the two indoor units are both opened, and the fourth electronic expansion valve 8 is fully opened. Taking the first indoor unit as an example, the high-temperature and high-pressure gaseous refrigerant from the outlet of the compressor 1 enters the outdoor heat exchanger 3 through the d2 and c2 ports of the second four-way valve 6, and is condensed by the outdoor heat exchanger 3 to obtain high temperature and high pressure The liquid refrigerant passes through the fourth electronic expansion valve 8 to the second interface of the economizer 4, where the refrigerant is divided into two paths, and a part of the refrigerant reaches the third interface of the economizer 4 after being throttled and depressurized by the third electronic expansion valve 7. At the interface, the low-temperature and low-pressure gaseous refrigerant obtained after heat exchange in the economizer 4 exits the fourth interface of the economizer 4 and flows back into the gas-liquid separator 2; the other way enters the economizer from the second interface of the economizer 4 4, it exchanges heat with the refrigerant that enters the economizer 4 from the third interface of the economizer 4 to achieve a preliminary cooling, and then comes out of the first interface of the economizer 4, and reaches the first indoor unit through the liquid pipe shut-off valve 17, respectively. The electronic expansion valve 121 and the second electronic expansion valve 131 throttling and depressurizing into low-temperature and low-pressure liquid refrigerant enter the first indoor heat exchanger 101 and the second indoor heat exchanger 111, and the low-temperature and low-pressure liquid refrigerant enters the first indoor heat exchanger 101 It exchanges heat with the air in the first indoor unit at the second indoor heat exchanger 111. The low-temperature and low-pressure liquid refrigerant absorbs heat and evaporates to obtain a low-temperature and low-pressure gaseous refrigerant, which reduces the temperature of the air in the first indoor unit, thereby reducing the air in the indoor space. Temperature, so as to achieve the purpose of refrigeration. The low-temperature and low-pressure gaseous refrigerant from the first indoor heat exchanger 101 flows back into the gas-liquid separator 2 through the e2 and s2 ports of the second four-way valve 6, and the low-temperature and low-pressure gaseous refrigerant from the second indoor heat exchanger 111 It flows back into the gas-liquid separator 2 through the e1 interface and the s1 interface of the first four-way valve 5. If 0℃≤Tin-Ts≤2℃, it means that the indoor ambient temperature is slightly higher than the set temperature and is about to reach the set temperature. Then, control the first

electronic expansion valve

121, 122 and the second

electronic expansion valve

131, 132 Open to a certain degree of opening respectively, and control the d1 interface and c1 interface of the first four-way valve 5 to communicate, the s1 interface and the e1 interface to communicate, the d2 interface and c2 interface of the second four-way valve 6 The e2 interface is connected to adjust the operating state of the air conditioning system to the normal cooling mode. Since the indoor environment temperature is close to the set temperature at this time, if you continue to operate in the normal cooling mode, the indoor environment temperature may be too low. You can reduce the compression The operating frequency of the machine and/or the rotation speed of the outdoor fan can reduce the output of the cooling capacity of the air-conditioning system, so as to prevent the indoor environment temperature from dropping too much and causing discomfort. Reducing the output of the refrigeration capacity by reducing the operating frequency of the compressor and the speed of the outdoor fan is a conventional technical means, and will not be repeated here.

Those skilled in the art can understand that, in the above control steps, the first electronic control valve 151 and the second electronic control valve 161 of the first indoor unit, the first electronic control valve 152 and the second electronic control valve 161 of the second indoor unit The electric control valves 162 are all open, or the second electric control valve 161 of the first indoor unit and the second electric control valve 162 of the second indoor unit are opened, and the first electric control valve 151 and the second indoor unit of the first indoor unit are closed.的第一电控阀152。 The first electronic control valve 152. Taking the first electronic control valve 151 and the second electronic control valve 161 in the first indoor unit as an example, the low-temperature and low-pressure gaseous refrigerant from the second indoor heat exchanger 111 can pass through the second electronic control valve 161 and then The e1 and s1 ports of the first four-way valve 5 are returned to the gas-liquid separator 2, and can also be connected to the low-temperature and low-pressure gaseous state from the first indoor heat exchanger 101 via the connecting pipe 141 and the first electronic control valve 151. The refrigerant merges, and then returns to the gas-liquid separator 2 through the e2 interface and the s2 interface of the second four-way valve 6 after merging.

Referring to Fig. 8, Fig. 8 is a fourth flowchart of a control method of a multi-unit air-conditioning system according to an embodiment of the present invention. As shown in Fig. 8, the control method of a multi-unit air-conditioning system includes:

Step S401: Obtain the indoor ambient temperature (Tin) in the heating mode;

Step S402: Calculate the difference between the indoor ambient temperature (Tin) and the set temperature (Ts), if Ts-Tin<0°C, execute step S403;

Step S403: Close the first electronic expansion valve or the second electronic expansion valve;

Step S404: recalculate the difference between the indoor ambient temperature (Tin) and the set temperature (Ts), if Ts-Tin<0°C, execute step S405;

Step S405: controlling the first electronic expansion valve and the second electronic expansion valve to respectively open to a certain degree of opening, and controlling the first four-way valve to switch to the first working state, and controlling the second four-way valve to switch to the second working state;

Step S406: Control the first electronic control valve of the first indoor unit to be closed, the second electronic control valve to open, and the first electronic control valve of the second indoor unit to open and the second electronic control valve to close.

Through the above setting method, as shown in Figure 4, in the case that the first indoor unit and the second indoor unit are both in heating mode, if the set temperature (Ts)-the indoor ambient temperature (Tin) <0°C, then, First close the first

electronic expansion valve

121, 122 or the second

electronic expansion valve

131, 132, so that there are only the first

indoor heat exchanger

101, 102 and the second indoor heat exchanger 111 in the first indoor unit and the second indoor unit , 112 is used as a condenser to increase the indoor ambient temperature, so that the heat output to the corresponding indoor space through the first indoor unit and the second indoor unit will be reduced, and the indoor ambient temperature of the corresponding indoor space will be corresponding Land appropriately lowered. After this state continues for a period of time, if Ts-Tin is still less than 0°C, then the first

electronic expansion valve

121, 122 and the second

electronic expansion valve

131, 132 are controlled to open to a certain degree of opening, and then the first four-way valve 5 Switch to the first working state, that is, the d1 interface and c1 interface of the first four-way valve are connected, and the s1 interface and e1 interface are connected, and the second four-way valve 6 is switched to the second working state, that is, the second four-way valve. The d2 interface and e2 interface of the valve are connected, and the s2 interface and c2 interface are connected. In addition, the first

electronic expansion valve

121, 122 is fully opened, and the second

electronic expansion valve

131, 132 is opened to a certain angle to turn on the first indoor unit And the second

electronic control valve

161, 162 of the second indoor unit, close the first

electronic control valve

151, 152 of the first indoor unit and the second indoor unit, and the fourth electronic expansion valve is opened to a certain degree of opening. Both the first indoor unit and the second indoor unit are adjusted in the same way. Taking the first indoor unit as an example, the high-temperature and high-pressure gaseous refrigerant from the compressor 1 reaches the first indoor unit through the d2 and e2 ports of the second four-way valve 6 At the second interface of the first indoor heat exchanger 101 of the first indoor unit, and enter the first indoor heat exchanger 101 of the first indoor unit through the second interface of the first indoor heat exchanger 101 of the first indoor unit, the high temperature and high pressure gaseous refrigerant At the first indoor heat exchanger 101 of the first indoor unit, heat is released and condensed to obtain a high-temperature and high-pressure liquid refrigerant. The electronic expansion valve 121 is divided into two paths: the first high-temperature and high-pressure liquid refrigerant is throttled and pressure-reduced by the second electronic expansion valve 131 of the first indoor unit, and then enters the second indoor heat exchanger 111 of the first indoor unit. The second indoor heat exchanger 111 of an indoor unit absorbs heat and evaporates to obtain a low-temperature and low-pressure gaseous refrigerant, which then passes through the second electronic control valve 161 of the first indoor unit, the e1 interface and the s1 interface of the first four-way valve 5, and returns to Gas-liquid separator 2; the second high-temperature and high-pressure liquid refrigerant directly reaches the first interface of the economizer 4, and then comes out of the second interface of the economizer 4. The refrigerant from the second interface of the economizer 4 is divided into two routes: All the way through the third electronic expansion valve 7 throttling and depressurizing, it becomes a low-temperature and low-pressure liquid refrigerant and reaches the third interface of the economizer 4. The first port of the economizer 4 enters the high-temperature and high-pressure liquid refrigerant to exchange heat to obtain low-temperature and low-pressure gaseous refrigerant, and then exits the fourth port of the economizer 4, and then returns to the gas-liquid separator 2; the second path is from the economizer 4 After exiting the second interface of the fourth electronic expansion valve 8, the low-temperature and low-pressure liquid refrigerant is obtained after being throttled and decompressed by the fourth electronic expansion valve 8. The c2 interface and s2 interface return to the gas-liquid separator 2. In this way, the refrigerant also releases heat and condenses at the first

indoor heat exchangers

101 and 102 in the first indoor unit and the second indoor unit, and absorbs heat and evaporates at the second

indoor heat exchangers

111 and 112. The air in the first indoor unit and the second indoor unit is heated at the first

indoor heat exchanger

101 and 102, and cooled at the second

indoor heat exchanger

111, 112. In this way, the air from the first indoor unit and the second indoor unit The temperature of the air entering the indoor space can be the same as the indoor ambient temperature or slightly lower than the temperature in the normal heating mode, so that the indoor constant temperature can be maintained or the temperature of the indoor space where the first indoor unit and the second indoor unit are located can be appropriately reduced. Therefore, it is possible to avoid the discomfort caused by the frequent start and stop of the compressor and the excessively high indoor ambient temperature in the heating mode.

Further, if the users of the indoor space where the first indoor unit and the second indoor unit are located have different requirements for the indoor environment temperature, for example, the user of the indoor space where the user in the first indoor unit is located wants the indoor environment temperature not to continue. Increase (or it can be understood that the difference (Ts-Tin) between the indoor environment temperature of the indoor space where the first indoor unit is located and the set temperature is less than 0°C), the user of the indoor space where the second indoor unit is located wants the indoor environment temperature Higher (or it can be understood that the difference between the indoor ambient temperature of the indoor space where the second indoor unit is located and the set temperature (Ts-Tin) is greater than or equal to 0°C), so that the first indoor unit of the first indoor unit One of the heat exchanger 101 and the second indoor heat exchanger 111 is transformed into an evaporator, the other still serves as a condenser, and the first indoor heat exchanger 102 and the second indoor heat exchanger 112 of the second indoor unit still serve as Condenser. Specifically, step S406 is executed while step S405 is executed, the d1 interface of the first four-way valve 5 is connected to the c1 interface, the e1 interface is connected to the s1 interface, the d2 interface of the second four-way valve 6 is connected to the e2 interface, and the c2 interface is connected to the s2. The interface is connected, the first electronic expansion valve 121 in the first indoor unit is fully opened, the second electronic expansion valve 131 is opened to a certain degree of opening, the first electronic expansion valve 122 and the second electronic expansion valve 132 in the second indoor unit All are fully open, close the first electronic control valve 151 of the first indoor unit, open the second electronic control valve 161 of the first indoor unit, open the first electronic control valve 152 of the second indoor unit, and close the first electronic control valve of the second indoor unit. Two electric control valve 162. In this way, the high temperature and high pressure refrigerant from the compressor can enter the first indoor heat exchanger 101 of the first indoor unit and the first indoor heat exchanger 102 of the second indoor unit through the d2 interface and e2 interface of the second four-way valve, respectively. And the second indoor heat exchanger 112, but can’t enter the second indoor heat exchanger 111 of the first indoor unit. The second indoor heat exchanger 111. Specifically, the high-temperature and high-pressure gaseous refrigerant from the compressor 1 reaches the second port and the second chamber of the first indoor heat exchanger 101 of the first indoor unit through the d2 port and e2 port of the second four-way valve 6 respectively. The second interface of the first indoor heat exchanger 102 of the machine.

Next, the flow path of the refrigerant in the first indoor unit and the second indoor unit will be described separately. The flow path of the high-temperature and high-pressure gaseous refrigerant in the first indoor unit is: the high-temperature and high-pressure gaseous refrigerant exchanges heat through the first indoor unit of the first indoor unit The second interface of the first indoor unit 101 enters the first indoor heat exchanger 101 of the first indoor unit. The first indoor heat exchanger 101 of the first indoor unit releases heat and condenses to obtain a high-temperature and high-pressure liquid refrigerant. The second interface of an indoor heat exchanger 101 is divided into two paths after passing through the first electronic expansion valve 121 of the first indoor unit: the first high-temperature and high-pressure liquid refrigerant passes through the second electronic expansion valve 131 of the first indoor unit After decompression, the flow becomes a low-temperature and low-pressure liquid refrigerant and enters the second indoor heat exchanger 111 of the first indoor unit. The second indoor heat exchanger 111 of the first indoor unit absorbs heat and evaporates to obtain a low-temperature and low-pressure gaseous refrigerant, and then reaches At the second electronic control valve 161 of the first indoor unit, it flows back to the gas-liquid separator 2 through the e1 and s1 ports of the first four-way valve; the second high-temperature and high-pressure liquid refrigerant directly reaches the first port of the economizer 4 Place. That is, the refrigerant releases heat and condenses at the first indoor heat exchanger 101 of the first indoor unit, absorbs heat and evaporates at the second indoor heat exchanger 111, and the air in the first indoor unit heats up at the first indoor heat exchanger 101 , Cooling at the second indoor heat exchanger 111, in this way, the total amount of heat output from the first indoor unit is reduced compared to before, so that the temperature of the indoor space where the first indoor unit is located can be appropriately reduced.

The flow path of the refrigerant in the second indoor unit is: the high-temperature and high-pressure gaseous refrigerant is divided into two paths at the second interface of the first indoor heat exchanger 102 of the second indoor unit: the first high-temperature and high-pressure gaseous refrigerant directly passes through the second indoor unit The second interface of the first indoor heat exchanger 102 of the unit enters the first indoor heat exchanger 102 of the second indoor unit, and the high-temperature and high-pressure gaseous refrigerant releases heat and condenses at the first indoor heat exchanger 102 of the second indoor unit to obtain a high temperature High-pressure liquid refrigerant; the second way enters the second room through the communication pipeline 142 of the second indoor unit, the first electronic control valve 152 of the second indoor unit, and the second interface of the second indoor heat exchanger 112 of the second indoor unit In the second indoor heat exchanger 112 of the second indoor unit, the high-temperature and high-pressure gaseous refrigerant releases heat and condenses at the second indoor heat exchanger 112 of the second indoor unit to obtain a high-temperature and high-pressure liquid refrigerant. That is, the refrigerant is condensed at the first indoor heat exchanger 102 and the second indoor heat exchanger 112 of the second indoor unit, and the air in the second indoor unit is successively at the first indoor heat exchanger 102 and the second indoor unit. The heat exchanger 112 generates heat.

The refrigerant coming out of the first indoor heat exchanger 102 of the second indoor unit and passing through the first electronic expansion valve 122 of the second indoor unit, and the refrigerant coming out of the second indoor heat exchanger 112 of the second indoor unit, passing through the second indoor unit The refrigerant after the second electronic expansion valve 132 of the indoor unit merges, and the merged high-temperature and high-pressure liquid refrigerant merges with the second high-temperature and high-pressure liquid refrigerant from the first indoor heat exchanger 101 of the first indoor unit, and then reaches the economy together. At the first port of the economizer 4, and then from the second port of the economizer 4, the refrigerant from the second port of the economizer 4 is divided into two paths: one path is reduced by the third electronic expansion valve 7 and becomes low temperature and low pressure. The liquid refrigerant reaches the third port of the economizer 4, enters the economizer 4 from the third port, and exchanges heat with the refrigerant that enters the economizer 4 from the first port of the economizer 4 to obtain a low-temperature and low-pressure gaseous refrigerant. When the interface comes out, it returns to the gas-liquid separator 2; the other path is throttled and reduced by the fourth electronic expansion valve 8 and becomes a low-temperature and low-pressure liquid refrigerant. The low-temperature and low-pressure liquid refrigerant absorbs heat and evaporates at the outdoor heat exchanger 3 to obtain low temperature and low pressure. The gaseous refrigerant and then the low-temperature and low-pressure gaseous refrigerant return to the gas-liquid separator 2 through the c2 and s2 ports of the second four-way valve 6.

Through this arrangement, the heating of the first indoor heat exchanger 101 and the cooling of the second indoor heat exchanger 111 of the first indoor unit, and the first indoor heat exchanger 102 and the second indoor unit of the second indoor unit are realized. The heat exchanger 112 heats the two indoor units in different heating operation modes, so that the difference between the users of the indoor space where the first indoor unit and the second indoor unit are located can be met without stopping the compressor. need.

Referring to FIG. 9, FIG. 9 is a fifth flowchart of a control method of a multi-unit air conditioning system according to an embodiment of the present invention. As shown in Figure 9, the control method of the multi-connected air conditioning system includes:

Step S501: Obtain the indoor ambient temperature (Tin) in the heating mode;

Step S502: Calculate the difference between the indoor ambient temperature (Tin) and the set temperature (Ts): if 0°C≤Ts-Tin≤2°C, go to step S503; if Ts-Tin>2°C, go to step S504;

Step S503: Control the first electronic expansion valve and the second electronic expansion valve to open to a certain degree of opening respectively, and control the first four-way valve and the second four-way valve to switch to the second working state, and reduce the operating frequency of the compressor. /Or the speed of the outdoor fan;

Step S504: The compressor and the outdoor fan are operated at the rated frequency and the rated speed, the first electronic expansion valve and the second electronic expansion valve are controlled to open to a certain degree of opening respectively, and the first four-way valve and the second four-way valve are controlled to switch To the second working state.

Through the above setting method and shown in Figure 2, when the first indoor unit and the second indoor unit are both in heating mode, if Ts-Tin>2℃, it means that the indoor ambient temperature has not reached the set temperature , It needs to continue to heat up, then control the air conditioning system to operate in the normal heating mode. Specifically, the d1 interface and e1 interface of the first four-way valve 5 are connected, the c1 interface and the s1 interface are connected, and the d2 interface of the second four-way valve 6 Connected to the e2 interface, the c2 interface is connected to the s2 interface, the first

electronic expansion valve

121, 122 and the second

electronic expansion valve

131, 132 of the first indoor unit and the second indoor unit are all fully opened, and the first indoor unit and the second indoor unit are fully opened. The first

electronic control valves

151 and 152 of the indoor unit are all closed, the second

electronic control valves

161 and 162 are all opened, and the fourth electronic expansion valve 8 is opened to a certain degree of opening. Taking the first indoor unit as an example, the high-temperature and high-pressure gaseous refrigerant from the outlet of the compressor 1 is divided into two paths. Interface, enter the second indoor heat exchanger 111 from the second interface of the second indoor heat exchanger 111 through the first interface of the second electronic control valve 161, in the second indoor heat exchanger 111 and the first indoor unit The high-temperature and high-pressure gaseous refrigerant heats and condenses to obtain high-temperature and high-pressure liquid refrigerant, which increases the temperature of the air in the first indoor unit; the second way reaches the first room through the d2 and e2 ports of the second four-way valve The second port of the heat exchanger 101 enters the first indoor heat exchanger 101 from its second port, and exchanges heat with the air in the indoor space in the first indoor heat exchanger 101. The high temperature and high pressure gaseous refrigerant heats and condenses to obtain high temperature and high pressure. The liquid refrigerant increases the temperature of the air in the first indoor unit, thereby increasing the temperature of the indoor space. In this way, the purpose of heating is achieved. A high-temperature and high-pressure liquid refrigerant from the first indoor heat exchanger 101 and after passing through the first electronic expansion valve 121, and a high-temperature and high-pressure liquid refrigerant from the second indoor heat exchanger 111 after passing through the second electronic expansion valve 131 , The two high-temperature and high-pressure liquid refrigerants merge to reach the first port of economizer 4, and then come out from the second port of economizer 4. The high-temperature and high-pressure liquid refrigerant from the second port of economizer 4 is divided into two paths: After being decompressed by the third electronic expansion valve 7, it reaches the third port of the economizer 4, and then enters the economizer 4 from the third port, and exchanges heat with the high temperature and high pressure liquid refrigerant that enters the economizer 4 from the first port of the economizer 4 Obtain the low-temperature and low-pressure gaseous refrigerant, and then come out from the fourth port, and then return to the gas-liquid separator 2; the other way comes out of the second port of the economizer 4 and is throttled and decompressed by the fourth electronic expansion valve 8 and then replaced outdoors The heat exchanger 3 exchanges heat with the outdoor environment to obtain a low-temperature and low-pressure gaseous refrigerant. This part of the low-temperature and low-pressure gaseous refrigerant is returned to the gas-liquid separator 2 through the c2 and s2 ports of the second four-way valve 6. If 0℃≤Ts-Tin≤2℃, it means that the indoor ambient temperature is slightly higher than the set temperature and is about to reach the set temperature. Then, control the first

electronic expansion valve

121, 122 and the second

electronic expansion valve

131, 132 Open to a certain degree of opening respectively, and control the d1 interface and e1 interface of the first four-way valve 5 to communicate, the s1 interface and the c1 interface to communicate, and the d2 interface and e2 interface of the second four-way valve 6 to communicate, the s2 interface and The c2 interface is connected to adjust the operating state of the air-conditioning system to the normal heating mode. At this time, the indoor environment temperature is close to the set temperature. If you continue to operate in the normal heating mode, the indoor environment temperature may be too high. Reduce the operating frequency of the compressor and/or the rotation speed of the outdoor fan to reduce the heating output of the air conditioning system, thereby avoiding discomfort caused by too high indoor ambient temperature.

Those skilled in the art can understand that, in the above control steps, the first electronic control valve 151 and the second electronic control valve 161 of the first indoor unit, the first electronic control valve 152 and the second electronic control valve 161 of the second indoor unit Both the electric control valves 162 are opened, or the second electric control valve 161 of the first indoor unit and the second electric control valve 162 of the second indoor unit are both opened, and the first electric control valve 151 and the second electric control valve 151 of the first indoor unit are opened. The first electronic control valves 152 of the indoor unit are all closed. Taking the first electronic control valve 151 and the second electronic control valve 161 in the first indoor unit as an example, the high-temperature and high-pressure gaseous refrigerant from the compressor 1 can enter the second indoor heat exchanger through two different paths : One of the paths is through the d1 and e1 ports of the first four-way valve 5, and the second electronically controlled valve 161 enters the second indoor heat exchanger; the other path is through the d2 and e2 ports of the second four-way valve 6 , The connecting pipeline 141 and the first electronic control valve 151 enter the second indoor heat exchanger. The refrigerant releases heat and condenses in the first indoor heat exchanger 101 and the second indoor heat exchanger 111, and the subsequent refrigerant path is the same as the above steps.

The following takes the refrigeration mode as an example to illustrate the specific control process of the air conditioning system of the present invention:

(1) During the operation of the air conditioning system in the cooling mode, the indoor ambient temperature and the set temperature are obtained, and the difference between the indoor ambient temperature and the set temperature is calculated. The difference between the indoor ambient temperature and the set temperature is greater than 2°C (Tin- Ts>2℃), the air-conditioning system operates in the normal cooling mode: the first electronic expansion valve and the second electronic expansion valve are opened to a certain degree respectively, and the first four-way valve and the second four-way valve are both switched to the first In working condition, the compressor and outdoor fan operate according to the rated frequency and rated speed.

(2) After running in the above state for a period of time, the indoor ambient temperature will decrease, continue to obtain the indoor ambient temperature and calculate the difference between it and the set temperature. When 0℃≤Tin-Ts≤2℃, reduce the compressor operation appropriately The frequency and the rotation speed of the outdoor fan, the operating status of the first electronic expansion valve and the second electronic expansion valve, the first four-way valve and the second four-way valve remain unchanged, reducing the output of refrigeration capacity. Otherwise, if Tin-Ts>2°C, keep the air-conditioning system running in the normal cooling mode.

(3) After running for a period of time in the state of reducing compressor frequency and outdoor unit speed, if the indoor environment temperature continues to decrease and the difference between the indoor environment temperature and the set temperature satisfies Tin-Ts<0°C, the first switch will be turned off. The electronic expansion valve continues to reduce the output of refrigeration capacity. Otherwise, if 0°C≤Tin-Ts≤2°C, the air conditioning system is controlled to maintain the current operating mode state.

(4) After the above-mentioned state of closing the first electronic expansion valve for a period of time, if Tin-Ts is still less than 0°C, the first electronic expansion valve and the second electronic expansion valve are controlled to open to a certain degree of opening respectively, and the first electronic expansion valve is controlled to open to a certain degree. The one four-way valve is switched to the second working state, and the second four-way valve is switched to the first working state, so that one of the first indoor heat exchanger and the second indoor heat exchanger in the indoor unit is used as a condenser and one As an evaporator, the temperature of the air entering the indoor space from the first indoor unit and the second indoor unit can be the same as the indoor ambient temperature or slightly higher than the temperature in the normal cooling mode, so that the indoor constant temperature can be maintained or the first indoor unit can be appropriately increased. The temperature of the indoor space where the first indoor unit and the second indoor unit are located. Otherwise, if Tin-Ts≥0°C, control the operation of the air-conditioning system in the manner in step (2) or (3).

(5) If users of indoor spaces where different indoor units of the air-conditioning system are located have different requirements, or different indoor spaces have different indoor ambient temperatures, different indoor units need to be in different operating states. Taking the air conditioner indoor unit including the first indoor unit and the second indoor unit as an example, then on the basis of step (4), control the first electronic control valve of the first indoor unit to be closed, the second electronic control valve to open, and the second The first electronic control valve of the indoor unit is opened, and the second electronic control valve is closed, so that one of the first indoor heat exchanger and the second indoor heat exchanger in the first indoor unit can be used as a condenser and the other can be used as an evaporator. The first indoor heat exchanger and the second indoor heat exchanger of the second indoor unit are still used as evaporators.

It should be noted that the contribution of the present application to the prior art lies in the on-off control of the first electronic expansion valve and the second electronic expansion valve under different differences, and the switching of the first four-way valve and the second four-way valve The control is not the control of the specific throttling and pressure reduction opening when the first electronic expansion valve and the second electronic expansion valve are opened. Therefore, although "a certain opening" is used in the context for description, this Those skilled in the art can understand that the "certain opening degree" in this application can be the same opening degree, but in more cases it is a different opening degree, and the opening degree is as long as it can achieve the throttling and pressure reduction of the application. The function is sufficient, and those skilled in the art can make adjustments based on the actual situation.

In summary, in the preferred technical solution of the present invention, the opening degree of the first electronic expansion valve/second electronic expansion valve is selectively controlled according to the difference between the indoor ambient temperature and the set temperature, and/or Switch the working state of the first four-way valve/the second four-way valve, and control the opening and closing of the first

electric control valves

151, 152 and the second

electric control valves

161, 162 of the first indoor unit and the second indoor unit, The closed loop formed by the refrigerant between the compressor 1, the first

indoor heat exchanger

101, 102, the second

indoor heat exchanger

111, 112, and the outdoor heat exchanger 3 can be changed to make the first

indoor heat exchanger

101, 102 and The second

indoor heat exchangers

111 and 112 are in the same or different operating states, so that the cooling capacity or the heating output of the indoor unit can be adjusted as required, so as to better adjust the ambient temperature of the indoor space.

It should be noted that although the detailed steps of the method of the present invention are described in detail above, those skilled in the art can combine, split and exchange the order of the above steps without departing from the basic principles of the present invention. The modified technical solution does not change the basic idea of the present invention, and therefore also falls within the protection scope of the present invention. For example, although the above control method is described in conjunction with the first

electronic control valve

151, 152 and the second

electronic control valve

161, 162, it is obvious that the first

electronic control valve

151, 152 and the second electronic control valve are not provided. In the case of the

control valves

161 and 162, it is only necessary to delete the related control steps accordingly. Similarly, the above adjustment methods are also applicable to the control of the third electronic expansion valve 7 and the fourth electronic expansion valve 8.

In addition, those skilled in the art can understand that although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments means that they are within the scope of the present invention. Within and form different embodiments. For example, in the claims of the invention, any one of the claimed embodiments can be used in any combination.

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

Claims

A control method of a multi-unit air conditioning system, wherein the multi-unit air conditioning system includes an outdoor unit and at least one indoor unit, and the indoor unit includes a first indoor heat exchanger, a second indoor heat exchanger, A first electronic expansion valve and a second electronic expansion valve. The outdoor unit includes a compressor, a first four-way valve, a second four-way valve, and an outdoor heat exchanger, and the outdoor heat exchanger is equipped with an outdoor fan,

Wherein, the first four-way valve has four ports d1, c1, s1, and e1, and the second four-way valve has four ports d2, c2, s2, and e2,

The first interface of the first indoor heat exchanger is connected to the first interface of the first electronic expansion valve, and the second interface of the first indoor heat exchanger is connected to the e2 interface of the second four-way valve The first port of the second indoor heat exchanger is connected to the first port of the second electronic expansion valve, and the second port of the second indoor heat exchanger is connected to the first four-way valve The e1 interface is connected,

The outlet of the compressor is respectively connected with the d1 interface of the first four-way valve and the d2 interface of the second four-way valve, and the inlet of the compressor is respectively connected with the s1 interface of the first four-way valve Communicate with the s2 interface of the second four-way valve,

The first interface of the outdoor heat exchanger is connected to the c2 interface of the second four-way valve, and the second interface of the outdoor heat exchanger is respectively connected to the second interface of the first electronic expansion valve and the The second interface of the second electronic expansion valve is connected;

The c1 interface of the first four-way valve is cut off;

The control method includes:

Obtain indoor ambient temperature;

Calculating the difference between the indoor ambient temperature and the set temperature;

According to the difference, selectively control the opening and closing of the first electronic expansion valve/the second electronic expansion valve, and/or switch the operation of the first four-way valve/the second four-way valve Status in order to adjust the operating status of the first indoor heat exchanger and the second indoor heat exchanger.
4. The control method according to claim 1, wherein “the first electronic expansion valve/the second electronic expansion valve is selectively controlled to open and close according to the difference, and/or the The step of "the working state of the first four-way valve/the second four-way valve" further includes:

If the difference is less than the first threshold, the first electronic expansion valve or the second electronic expansion valve is controlled to close.
The control method according to claim 2, characterized in that, the first indoor heat exchanger and the second indoor heat exchanger are arranged in sequence along the air flow direction, "based on the difference, selectively control The step of opening and closing the first electronic expansion valve/the second electronic expansion valve, and/or switching the working state of the first four-way valve/the second four-way valve, further includes:

When the first electronic expansion valve or the second electronic expansion valve is in the closed state and the air conditioning system is operating in the cooling mode, if the difference is still less than the first threshold, the first electronic expansion is controlled The valve and the second electronic expansion valve are respectively opened to a certain degree of opening, and the first four-way valve is controlled to switch to the second working state, and the second four-way valve is controlled to switch to the first working state;

Wherein, the second working state of the first four-way valve is that the d1 interface and e1 interface of the first four-way valve are connected, and the s1 interface and c1 interface are connected. The first working state of the second four-way valve is The state is that the d2 interface and the c2 interface of the second four-way valve are connected, and the s2 interface and the e2 interface are connected.
The control method according to claim 2 or 3, characterized in that, "according to the difference, the opening and closing of the first electronic expansion valve/the second electronic expansion valve are selectively controlled, and/or switched The step of "the working state of the first four-way valve/the second four-way valve" further includes:

When the air conditioning system is operating in the cooling mode, if the difference is greater than the first threshold and less than the second threshold, control the first electronic expansion valve and the second electronic expansion valve to open to a certain degree of opening respectively , Controlling both the first four-way valve and the second four-way valve to switch to the first working state, and reducing the operating frequency of the compressor and/or the rotation speed of the outdoor fan;

Wherein, the first working state of the first four-way valve is that the d1 interface and the c1 interface of the first four-way valve are connected, the s1 interface and the e1 interface are connected, and the first working state of the second four-way valve is The state is that the d2 interface and the c2 interface of the second four-way valve are connected, and the s2 interface and the e2 interface are connected.
The control method according to claim 2, characterized in that, the first indoor heat exchanger and the second indoor heat exchanger are arranged in sequence along the air flow direction, "based on the difference, selectively control The step of opening and closing the first electronic expansion valve/the second electronic expansion valve, and/or switching the working state of the first four-way valve/the second four-way valve, further includes:

When the first electronic expansion valve or the second electronic expansion valve is in the closed state and the air-conditioning system is operating in the heating mode, if the difference is still less than the first threshold, the first electronic expansion valve is controlled The expansion valve and the second electronic expansion valve are opened to a certain degree of opening respectively, and the first four-way valve is controlled to switch to the first working state, and the second four-way valve is controlled to switch to the second working state;

Wherein, the first working state of the first four-way valve is that the d1 interface and the c1 interface of the first four-way valve are connected, and the s1 interface and the e1 interface are connected, and the second working state of the second four-way valve is The state is that the d2 interface and the e2 interface of the second four-way valve are connected, and the s2 interface and the c2 interface are connected.
The control method according to claim 2 or 5, wherein the first indoor heat exchanger and the second indoor heat exchanger are arranged in sequence along the air flow direction, "according to the difference, selective The step of controlling the opening and closing of the first electronic expansion valve/the second electronic expansion valve and/or switching the working state of the first four-way valve/the second four-way valve further includes:

When the air conditioning system is operating in the heating mode, if the difference is greater than the first threshold and less than the second threshold, the first electronic expansion valve and the second electronic expansion valve are controlled to be opened to a certain opening respectively Control the first four-way valve and the second four-way valve to switch to the second working state, and reduce the operating frequency of the compressor and/or the rotation speed of the outdoor fan;

Wherein, the second working state of the first four-way valve is that the d1 interface and e1 interface of the first four-way valve are connected, the s1 interface and the c1 interface are connected, and the second working state of the second four-way valve is The state is that the d2 interface and the e2 interface of the second four-way valve are connected, and the s2 interface and the c2 interface are connected.
The control method according to claim 3 or 5, wherein a communication pipeline is provided between the second interface of the first indoor heat exchanger and the second interface of the second indoor heat exchanger, so The communicating pipeline is provided with a first electronic control valve, the second interface of the second indoor heat exchanger is also provided with a second electronic control valve, and one end of the communicating pipeline is provided in the second indoor heat exchanger Between the second interface and the second electronic control valve.
The control method according to claim 7, characterized in that, “based on the difference, the opening and closing of the first electronic expansion valve/the second electronic expansion valve is selectively controlled, and/or the The step of "the working state of the first four-way valve/the second four-way valve" further includes:

If the difference is still less than the first threshold, controlling the first electronic control valve to close and the second electronic control valve to open;

Otherwise, control at least one of the first electronic control valve and the second electronic control valve to open.
The control method according to claim 8, wherein the multi-unit air conditioning system comprises a first indoor unit and a second indoor unit, and the first indoor unit and the second indoor unit Both an indoor heat exchanger and the second indoor heat exchanger are arranged in sequence along the air flow direction,

"According to the difference, selectively control the opening and closing of the first electronic expansion valve/the second electronic expansion valve, and/or switch the operation of the first four-way valve/the second four-way valve The steps of "status" further include:

If the difference value of the first indoor unit is still less than the first threshold value, and the difference value of the second indoor unit is greater than or equal to the first threshold value, control the first indoor unit The first electronic control valve is closed and the second electronic control valve is opened. At the same time, the first electronic control valve in the second indoor unit is controlled to be opened and the second electronic control valve is closed.
The control method according to any one of claims 1-9, characterized in that “selectively control the opening and closing of the first electronic expansion valve/the second electronic expansion valve according to the difference, Or the step of switching the working state of the first four-way valve/the second four-way valve" further includes:

If the difference is greater than the second threshold and the air-conditioning system is operating in the cooling mode, the first electronic expansion valve and the second electronic expansion valve are controlled to open to a certain degree of opening respectively, and the first electronic expansion valve is controlled to be opened to a certain degree. Both the four-way valve and the second four-way valve are switched to the first working state, and the compressor and the outdoor fan are controlled to operate at a rated frequency and a rated speed; and/or

If the difference is greater than the second threshold and the air-conditioning system is operating in the heating mode, the first electronic expansion valve and the second electronic expansion valve are controlled to open to a certain degree of opening respectively, and the first electronic expansion valve is controlled to open to a certain degree of opening. Both the one four-way valve and the second four-way valve are switched to the second working state, and the compressor and the outdoor fan are controlled to operate at a rated frequency and a rated speed;

Wherein, the first working state of the first four-way valve is that the d1 interface and the c1 interface of the first four-way valve are connected, and the s1 interface and the e1 interface are connected, and the second working state of the first four-way valve is The state is that the d1 interface and the e1 interface of the first four-way valve are connected, and the s1 interface and the c1 interface are connected, and the first working state of the second four-way valve is that the d2 interface of the second four-way valve and The c2 interface is connected, the s2 interface and the e2 interface are connected, and the second working state of the second four-way valve is that the d2 interface and the e2 interface of the second four-way valve are connected, and the s2 interface and the c2 interface are connected.