CN117232168A - Air conditioning system and control method thereof - Google Patents

Abstract

The invention discloses an air conditioning system and a control method thereof. The air conditioning system provided by the invention comprises a first heat exchanger loop, a second heat exchanger loop, a first sub heat exchange loop, a first heat exchanger and a control module. The first heat exchanger loop comprises a first outdoor heat exchanger and a first four-way valve, and the second heat exchanger loop comprises a second outdoor heat exchanger and a second four-way valve. By adopting the scheme, when the first outdoor heat exchanger needs defrosting, the reversing of the first four-way valve is controlled and controlled, and the valve position of the second four-way valve is kept unchanged, so that the first heat exchanger loop enters a refrigerating defrosting mode, and the second heat exchanger loop keeps a heating mode. The low-temperature refrigerant flowing out of the first outdoor heat exchanger does not influence the whole heating of the air conditioning system, the heating effect of the air conditioning system can be guaranteed, further continuous heating of the air conditioning system in a defrosting mode is realized, user use side temperature fluctuation during defrosting is avoided, and user use comfort is improved.

Description

Air conditioning system and control method thereof

Technical Field

The embodiment of the invention relates to the technical field of air conditioners, in particular to an air conditioning system and a control method thereof.

Background

Under heating working conditions, the surface temperature of a heat exchanger of the air conditioning unit may reach below zero, and frosting occurs at the moment. The frosting can cause the heat transfer resistance of the heat exchanger to be increased, so that the heat exchange efficiency is reduced, and the reliability of the whole machine is affected. Therefore, the air conditioning unit needs to perform defrosting treatment after a period of heating operation. In the prior art, an air conditioning unit is generally switched from a heating mode to a refrigerating mode, and the temperature of a heat exchanger is increased in the refrigerating mode, so that the defrosting function is realized. When defrosting in this mode, air conditioning unit can't heat, leads to the user to use the side to take place that temperature fluctuation is great, influences user's use experience.

Disclosure of Invention

In view of the above, the present invention provides an air conditioning system and a control method thereof, so as to realize continuous heating of the air conditioning system in the defrosting process, avoid temperature fluctuation of a user side, and improve user comfort.

In a first aspect, an embodiment of the present invention provides an air conditioning system, including a first heat exchanger loop, a second heat exchanger loop, a first sub-heat exchange loop, a first heat exchanger, and a control module;

the first heat exchanger loop comprises a first compressor, a first four-way valve, a first outdoor heat exchanger, a first indoor heat exchanger and a first gas-liquid separator which are connected with each other; the second heat exchanger loop comprises a second compressor, a second four-way valve, a second outdoor heat exchanger, a second indoor heat exchanger and a second gas-liquid separator which are connected with each other;

The first heat exchanger loop further comprises a first node and a second node, the first node is located in a connecting path of the first outdoor heat exchanger and the first indoor heat exchanger, and the second node is close to an air inlet end of the first gas-liquid separator; one end of the first sub heat exchange loop is connected to the first node, the other end of the first sub heat exchange loop is connected to the second node, and the first heat exchanger is located in the first sub heat exchange loop;

the control module is electrically connected with the first four-way valve and the second four-way valve, when the air conditioning system meets a first defrosting condition, the control module controls the first four-way valve to change direction and controls the valve position of the four-way valve to be unchanged, so that the first heat exchanger loop performs defrosting work, and the second heat exchanger loop continues to perform heating work.

In a second aspect, an embodiment of the present invention further provides a control method of an air conditioning system, which is applied to the air conditioning system provided by the embodiment of the present invention, where the control method includes:

when the air conditioning system meets a first defrosting condition, the reversing of the first four-way valve is controlled, and the valve position of the second four-way valve is controlled to be unchanged, so that the defrosting work of the first heat exchanger loop is performed, and the heating work of the second heat exchanger loop is continuously performed.

According to the air conditioning system provided by the embodiment of the invention, when the air conditioning system meets the first defrosting condition, the control module controls the first four-way valve to change direction and controls the valve position of the second four-way valve to be unchanged, so that the first heat exchanger loop performs defrosting work, and the second heat exchanger loop continues to perform heating work. By adopting the scheme, when the first outdoor heat exchanger needs defrosting, the first heat exchanger loop is controlled to enter a refrigerating defrosting mode, and the second heat exchanger loop keeps a heating mode. Because the low-temperature refrigerant in the first heat exchanger loop 1 does not flow into the first indoor heat exchanger any more, but directly returns to the first gas-liquid separator through the first heat exchanger, the low-temperature refrigerant flowing out of the first outdoor heat exchanger does not influence the whole heating of the air conditioning system, the heating effect of the air conditioning system can be ensured, the continuous heating of the air conditioning system in a defrosting mode is realized, the user use side temperature fluctuation in defrosting is avoided, and the user use comfort is improved.

Drawings

Fig. 1 is a schematic structural diagram of an air conditioning system according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of another air conditioning system according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of another air conditioning system according to an embodiment of the present invention;

Fig. 4 is a flowchart of an air conditioner control method according to an embodiment of the present invention;

fig. 5 is a control logic diagram of a control method of an air conditioning system according to an embodiment of the present invention.

Detailed Description

The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.

In order to improve the problem of temperature fluctuation during defrosting of an air conditioning system, fig. 1 is a schematic structural diagram of an air conditioning system according to an embodiment of the present invention, and referring to fig. 1, the air conditioning system is composed of a first heat exchanger loop 1, a second heat exchanger loop 2, a first sub heat exchanger loop 3, a first heat exchanger 4, and a control module (not shown in the figure). The first heat exchanger loop 1 comprises a first compressor 10, a first four-way valve 11, a first outdoor heat exchanger 12, a first indoor heat exchanger 13 and a first gas-liquid separator 14 which are connected with each other; the second heat exchanger circuit 2 includes a second compressor 20, a second four-way valve 21, a second outdoor heat exchanger 22, a second indoor heat exchanger 23, and a second gas-liquid separator 24, which are connected to each other. The first heat exchanger loop 1 comprises a first node 1a and a second node 1b, wherein the first node 1a is positioned in a connecting path of the first outdoor heat exchanger 12 and the first indoor heat exchanger 13, and the second node 1b is close to an air inlet end of the first gas-liquid separator 14; one end of the first sub heat exchange loop 3 is connected to the first node 1a, and the other end of the first sub heat exchange loop 3 is connected to the second node 1b; the first heat exchanger 4 is located in the first sub heat exchange loop 3. The control module is electrically connected with the first four-way valve 11 and the second four-way valve 21, and is used for controlling the reversing of the first four-way valve 11 and controlling the valve position of the second four-way valve 21 to be unchanged when the air conditioning system meets the first defrosting condition, so that the first heat exchanger loop 1 performs defrosting operation, and the second heat exchanger loop 2 continues to perform heating operation.

In the embodiment of the invention, at least two heat exchanger loops are arranged in an air conditioning system, and each heat exchanger loop is respectively provided with a compressor, a four-way valve, an outdoor heat exchanger, an indoor heat exchanger, a gas-liquid separator and other components. The present embodiment is described with the number of the first heat exchanger circuits 1 and the second heat exchanger circuits 2 being 1, but is not limited to this. The different loops are distinguished by lines of different thickness in fig. 1, and do not represent the actual structure.

In the heating mode, the first four-way valve 11 and the second four-way valve 21 are both positioned at a heating zone, the first pipe orifice A and the second pipe orifice B of the first four-way valve 11 (or the second four-way valve 21) are communicated, and the third pipe orifice C and the fourth pipe orifice D are communicated. The two heat exchanger loops heat together to exchange heat with the first outdoor heat exchanger 12 and the second outdoor heat exchanger 22. The first outdoor heat exchanger 12 and the second outdoor heat exchanger 22 may be fin heat exchangers, which are prone to frosting when used in a heating mode, and the air conditioning system may complete frosting of the first outdoor heat exchanger 12 and/or the second outdoor heat exchanger 22 under normal heating conditions.

Further, in order to realize continuous heating during defrosting, a first sub heat exchange loop 3 and a first heat exchanger 4 are additionally arranged in the air conditioning system, and the first sub heat exchange loop 3 is connected with part of the first sub heat exchange loop 3 in parallel through a first node 1a and a second node 1 b. The first heat exchanger 4 comprises a first fluid channel 40, the first fluid channel 40 being located in the first sub heat exchange circuit 3;

The following briefly describes the circulation of the refrigerant in the air conditioning system in a normal heating mode, which is understood as a mode in which the air conditioning system heats and does not require defrosting. The control module controls a first four-way valve 11 in the first heat exchanger loop 1 to be positioned at a heating zone, a high-temperature and high-pressure refrigerant coming out of an air outlet of the first compressor 10 enters a first indoor heat exchanger 13 after passing through the first four-way valve 11 and is condensed into a medium-temperature and high-pressure liquid refrigerant, then the medium-temperature and high-pressure liquid refrigerant is throttled into a low-temperature and low-pressure gas-liquid two-phase refrigerant by an electronic expansion valve in the first heat exchanger loop 1, heat exchange is carried out between the low-temperature and low-pressure gas-state refrigerant and outdoor air in a first outdoor heat exchanger 12, the low-temperature and low-pressure gas-state refrigerant is evaporated, the refrigerant then flows into a first gas-liquid separator 14 through the first four-way valve 11, the gas-state refrigerant is separated into a gas state and a liquid state in the first gas-liquid separator 14, and the gas-state refrigerant returns to the first compressor 10 for recirculation. The control logic of the second heat exchanger loop 2 is similar to that of the first heat exchanger loop 1, and the refrigerant flow is not repeated here.

Further, the first defrosting condition may be a condition that is satisfied when the first outdoor heat exchanger 12 needs to defrost, for example, the first defrosting condition may be that the surface temperature of the first outdoor heat exchanger 12 is less than a preset temperature, but is not limited thereto, and may be set by those skilled in the art according to actual requirements. In the invention, under the heating mode of the air conditioning system, the control module can judge whether the system meets the first defrosting condition, and when the system meets the first defrosting condition, the control module controls the first four-way valve 11 in the first heat exchanger loop 1 to be arranged at a refrigerating zone bit, controls the second four-way valve 21 in the second heat exchanger loop 2 to be still arranged at a heating zone bit, and can also adjust the first compressor 10 to run at defrosting frequency. The first four-way valve 11 shown in fig. 1 is positioned at a refrigeration zone, the second pipe orifice B is communicated with the third pipe orifice C, and the first pipe orifice A is communicated with the fourth pipe orifice D; the second four-way valve 22 is in the heating flag.

When the first four-way valve 11 is reversed, the flow direction of the refrigerant in the first heat exchanger loop 1 is changed, specifically, as follows, the high-temperature high-pressure gaseous refrigerant compressed by the first compressor 10 enters the first outdoor heat exchanger 12 after passing through the first four-way valve 11, the temperature of the first outdoor heat exchanger 12 is raised, the frost is formed, and the refrigerant is condensed into the high-temperature high-pressure liquid refrigerant at the first outdoor heat exchanger 12. The refrigerant flowing out of the first outdoor heat exchanger 12 reaches the first node 1a, and at this time, the control module controls the refrigerant to enter the first heat exchanger 4 and not enter the first indoor heat exchanger 13; the refrigerant entering the first sub heat exchange loop 3 flows to the second node 1b through the first heat exchanger 4, enters the first gas-liquid separator 14 through the second node 1b, and returns to the first compressor 10 for recirculation. Meanwhile, the valve position of the second four-way valve 21 is kept at a heating zone, the high-temperature high-pressure gaseous refrigerant compressed by the second compressor 20 enters the second indoor heat exchanger 23 after passing through the second four-way valve 21, heat exchange is carried out between the high-temperature high-pressure gaseous refrigerant and outdoor air in the second outdoor heat exchanger 22, the indoor temperature is continuously increased by the second indoor heat exchanger 23, the overall heating function of the air conditioning system is maintained, then the refrigerant enters the second outdoor heat exchanger 22 and exchanges heat with the outdoor air, finally the refrigerant enters the second gas-liquid separator 24 through the second four-way valve 21, and the gaseous refrigerant returns to the second compressor 20 for recirculation.

This arrangement corresponds to controlling the first heat exchanger loop 1 to enter the cooling defrosting mode when defrosting of the first outdoor heat exchanger 12 is required, and the second heat exchanger loop 2 is kept in the heating mode. Because the low-temperature refrigerant in the first heat exchanger loop 1 does not flow into the first indoor heat exchanger 13 any more, but directly returns to the first gas-liquid separator 14 through the first heat exchanger 4, the low-temperature refrigerant flowing out through the first outdoor heat exchanger 12 does not influence the whole heating of the air conditioning system, the heating effect of the air conditioning system can be ensured, the continuous heating of the air conditioning system in the defrosting mode is further realized, the user use side temperature fluctuation in defrosting is avoided, and the user use comfort is improved.

The type of the first heat exchanger 4 is not limited, and a person skilled in the art may set the first heat exchanger according to actual needs, for example, the first heat exchanger 4 may be a plate heat exchanger, such as an economizer, but is not limited thereto, and any heat exchanger capable of performing the function of the first heat exchanger 4 in the present invention is within the scope of the technical solution protected by the embodiments of the present invention.

Optionally, conventional setting components such as a filter 5 may be further disposed in the air conditioning circuit, which is not described in detail or limited in the present invention.

By adopting the scheme, when the first outdoor heat exchanger needs defrosting, the first heat exchanger loop is controlled to enter a refrigerating defrosting mode, and the second heat exchanger loop keeps a heating mode. Because the low-temperature refrigerant in the first refrigerator loop does not flow into the first indoor heat exchanger any more, but directly returns to the first gas-liquid separator through the first heat exchanger, the low-temperature refrigerant flowing out of the first outdoor heat exchanger does not influence the whole heating of the air conditioning system, the heating effect of the air conditioning system can be ensured, the continuous heating of the air conditioning system in a defrosting mode is realized, the user use side temperature fluctuation during defrosting is avoided, and the user use experience is improved.

Optionally, fig. 2 is a schematic structural diagram of another air conditioning system according to an embodiment of the present invention, referring to fig. 2, in an embodiment of the present invention, the first heat exchanger 4 may include a first fluid channel 40 and a second fluid channel 41, where the first fluid channel 40 is located in the first sub heat exchange loop 3, and the second fluid channel 41 is located in a connection path between the second outdoor heat exchanger 22 and the second indoor heat exchanger 23 in the second heat exchanger loop 2; the first indoor heat exchanger 13 may be multiplexed into the second indoor heat exchanger 23, and the first indoor heat exchanger 13 includes a first air inlet 13a, a second air inlet 13b, a first air outlet 13c, and a second air outlet 13d; the first air inlet 13a is connected with the first node 1a, the first air outlet 13c is connected with the first four-way valve 11, the second air inlet 13b is connected with the second outdoor heat exchanger 22 through the second fluid channel 41, and the second air outlet 13d is connected with the second four-way valve 21; the air conditioning system further includes a first electronic expansion valve 15, a second electronic expansion valve 30, and a third electronic expansion valve 25, the first electronic expansion valve 15 being located in a connection path of the first outdoor heat exchanger 12 and the first air intake port 13a, the second electronic expansion valve 30 being located in a connection path of the first node 1a and the first heat exchanger 4, the third electronic expansion valve 25 being located in a connection path of the second outdoor heat exchanger 22 and the first heat exchanger 4; the control module is further used for electrically connecting the first electronic expansion valve 15, the second electronic expansion valve 30 and the third electronic expansion valve 25, and controlling the first electronic expansion valve 15 to be closed and controlling the second electronic expansion valve 30 and the third electronic expansion valve 25 to be opened when the air conditioning system meets the first defrosting condition.

As shown in fig. 2, in the present embodiment, the first heat exchanger 4 may be located in the second heat exchanger circuit 2 at the same time, wherein the first fluid passage 40 of the first heat exchanger 4 is provided in the connection path of the first outdoor heat exchanger 12 and the first gas-liquid separator 14; the second fluid channel 41 of the first heat exchanger 4 is arranged in the second heat exchanger circuit 2 and in the connection path of the second outdoor heat exchanger 22 and the second indoor heat exchanger 23. The refrigerant in the first fluid passage 40 and the refrigerant in the second fluid passage 41 can exchange heat at the first heat exchanger 4.

Further, in the present embodiment, only one indoor heat exchanger may be provided in the air conditioning system, and the first heat exchanger circuit 1 and the second heat exchanger circuit 2 share the indoor heat exchanger. Illustratively, taking the first indoor heat exchanger 13 as an example, the first indoor heat exchanger 13 includes two air inlets and two air outlets, and the first air inlet 13a and the first air outlet 13c are located in the first heat exchanger loop 1 and are used for connecting the first outdoor heat exchanger 12 and the first pipe orifice a of the first four-way valve 11; a second air inlet 13b and a second air outlet 13d are located in the second heat exchanger loop 2 for communicating the second outdoor heat exchanger 22 with the first nozzle a of the second four-way valve 22.

With continued reference to fig. 2, a first electronic expansion valve 15, a second electronic expansion valve 30, and a third electronic expansion valve 25 are provided in the first heat exchanger loop 1, the first sub heat exchange loop 3, and the second heat exchanger loop 2, respectively. The first electronic expansion valve 15 is provided between the first node 1a and the first intake port 13a, the second electronic expansion valve 30 is provided between the first node 1a and the first fluid passage 40 of the first heat exchanger 4, and the third electronic expansion valve 25 is provided between the second outdoor heat exchanger 22 and the second fluid passage 41 of the first heat exchanger 4. The first electronic expansion valve 15, the second electronic expansion valve 30, and the third electronic expansion valve 25 are used to adjust the flow path of the refrigerant.

In this setting, if the control module determines that the air conditioning system meets the first defrosting condition, the control module may control the first four-way valve 11 to switch and control the first electronic expansion valve 15 to close, and control the second electronic expansion valve 30 and the third electronic expansion valve 25 to open. So that the refrigerant flowing out of the first outdoor heat exchanger 12 enters the first sub heat exchange circuit 3 and flows into the first heat exchanger 4 through the second electronic expansion valve 30, and does not enter the first indoor heat exchanger 13 any more. Correspondingly, the circulation flow direction of the refrigerant in the second heat exchanger loop 2 is as follows: the second compressor 20, the second four-way valve 21, the second air outlet 13d of the first indoor heat exchanger 13, the second air inlet 13b of the first indoor heat exchanger 13, the first heat exchanger 4, the third electronic expansion valve 25, the second outdoor heat exchanger 22, the second four-way valve 21, and the second gas-liquid separator 24.

It should be noted that, the air inlet or the air outlet of a certain component according to the embodiment of the present invention is only used to define the structure of the component, and not to define the flowing direction of the refrigerant. The refrigerant can flow from the air inlet to the air outlet, and can flow from the air outlet to the air inlet.

In the solution of this embodiment, by connecting the first heat exchanger 4 to the second heat exchanger loop 2, in the defrosting process of the first outdoor heat exchanger 12, the liquid refrigerant entering the first fluid channel 40 of the first heat exchanger 4 exchanges heat with the medium-temperature high-pressure liquid refrigerant entering the second fluid channel 41 to become gas, and then returns to the air suction port of the first compressor 10 after passing through the first gas-liquid separator 14, so that the liquid carrying of the first compressor 10 can be avoided, and the reliability of the air conditioning system is ensured.

Alternatively, in other possible embodiments, when the first defrosting condition is met, the control module may also control the first electronic expansion valve 15 and the second electronic expansion valve 30 to be opened at the same time, and control the opening degrees of the first electronic expansion valve 15 and the second electronic expansion valve 30 to adjust the flow rate of the refrigerant entering the first heat exchanger 4 and the first indoor heat exchanger 13 through the first node 1a, so as to adjust the pressures of the first heat exchanger loop 1 and the first sub heat exchange loop 3, thereby ensuring that the loop pressure is kept in a normal range.

Optionally, fig. 3 is a schematic structural diagram of another air conditioning system according to an embodiment of the present invention, in the air conditioning system shown in fig. 3, the first heat exchanger loop 1 is the same as the embodiment shown in fig. 2, and the first heat exchanger loop 1 and the second heat exchanger loop 2 still share one indoor heat exchanger. The difference is that the second heat exchanger loop 2 is disposed, referring to fig. 3, in this embodiment, the second heat exchanger loop 2 includes a main heat exchange loop 26 and a second sub heat exchange loop 27, and the main heat exchange loop 26 includes a second compressor 20, a second four-way valve 21, a second outdoor heat exchanger 22, a first indoor heat exchanger 13 (a second indoor heat exchanger 23), a second four-way valve 21 and a second gas-liquid separator 24, which are sequentially connected. The main heat exchange circuit 26 is further provided with a third node 26a and a fourth node 26b, wherein the third node 26a is located in a connection path between the second outdoor heat exchanger 22 and the first indoor heat exchanger 13 (the second indoor heat exchanger 23), and the fourth node 26b is close to the air inlet end of the second gas-liquid separator 24. One end of the second sub heat exchange circuit 27 is connected to the third node 26a, and the other end of the second sub heat exchange circuit 27 is connected to the fourth node 26b so as to be connected in parallel with a part of the main heat exchange circuit 26. The second fluid channel 41 of the first heat exchanger 4 is located in the second sub heat exchange loop 27.

Further, a fourth electronic expansion valve 28 is provided in the main heat exchange circuit 26 between the second outdoor heat exchanger 22 and the first indoor heat exchanger 13, and a fifth electronic expansion valve 29 is provided in the second sub heat exchange circuit 27 between the second outdoor heat exchanger 22 and the first heat exchanger 4.

If the control module detects that one of the outdoor heat exchangers (for example, the second outdoor heat exchanger 22) needs defrosting, the control module can control the second four-way valve 21 in the second heat exchanger loop 2 to switch (place in the refrigeration zone), the fourth electronic expansion valve 28 to close, and the fifth electronic expansion valve 29 to open. The circulating flow direction of the refrigerant in the second heat exchanger loop 2 is as follows: a second compressor 20, a second four-way valve 21, a second outdoor heat exchanger 22, a fifth electronic expansion valve 29, a first heat exchanger 4, a fourth node 26b, and a second gas-liquid separator 24. Meanwhile, the valve position of the first four-way valve 11 in the first heat exchanger loop 1 is controlled to be unchanged (the valve position is arranged at a heating zone), the first electronic expansion valve 15 in the first heat exchanger loop 1 is controlled to be opened, and the second electronic expansion valve 30 in the first sub heat exchange loop 3 is controlled to be closed. The circulating flow direction of the refrigerant in the first heat exchanger loop 1 is as follows: the first compressor 10, the first four-way valve 11, the first air outlet 13c of the first indoor heat exchanger 13, the first air inlet 13a of the first indoor heat exchanger 13, the first electronic expansion valve 15, the first outdoor heat exchanger 12, the first four-way valve 11, and the first gas-liquid separator 14. The first indoor heat exchanger 13 continuously heats up the indoor environment while defrosting the second outdoor heat exchanger 22 is ensured. The control logic when defrosting is required for the first outdoor heat exchanger 12 is similar and will not be described again.

Further, with continued reference to fig. 1, in an embodiment of the present invention, a first temperature sensor 6 and an ambient temperature sensor 7 may be provided in the air conditioning system; the first temperature sensor 6 is located on the first outdoor heat exchanger 12 for detecting the first temperature of the first outdoor heat exchanger 12 in real time, and the ambient temperature sensor 7 is for detecting the ambient temperature in real time. The control module (not shown in the figure) is electrically connected with the first temperature sensor 6 and the ambient temperature sensor 7 respectively, and is further used for determining whether the air conditioning system meets a first defrosting condition according to the first temperature, the ambient temperature and the defrosting time interval; the defrosting time interval is the time interval between the ending time of the last defrosting operation and the current time.

Specifically, as shown in fig. 1, the first temperature sensor 6 may be located on the housing of the first outdoor heat exchanger 12. For detecting in real time a first temperature of the first outdoor heat exchanger 12 (e.g., a surface temperature of the cabinet) and sending the first temperature to the control module; the setting of the ambient temperature sensor 7 is not limited, the position of the ambient temperature sensor 7 shown in the figure is only an example and does not represent the actual situation, it can be understood that the ambient temperature sensor 7 can be arranged outdoors for monitoring the ambient temperature in real time, and the ambient temperature sensor 7 sends the ambient temperature detected in real time to the control module.

The control module obtains the first temperature based on the first temperature sensor 6 and obtains the second temperature based on the environment temperature sensor 7, and meanwhile, the control module can also record the time when the last defrosting operation of the air conditioning system is finished. If the air conditioning system is defrosting for the first time, the last defrosting ending time is the starting time.

Further, this embodiment proposes an optional first defrosting condition determination manner, specifically, the first defrosting condition may include three determination targets, where the first determination target is T is less than or equal to Ta, T is an ambient temperature Ta and is an ambient temperature threshold, the second determination target is T-T1 is less than or equal to Tb, T1 is a first temperature, tb is a defrosting temperature difference threshold, the third determination target is Δt is less than or equal to Δt, Δt is a time interval threshold between a last defrosting end time and a current time, and Δt is a defrosting time interval threshold. The current time is the time at which the determination target is executed, and may be understood as the time in real time.

It will be appreciated that an ambient temperature less than or equal to the ambient temperature threshold value indicates that the current air conditioning system is in a heating mode, and that a difference between the ambient temperature and the first temperature greater than or equal to the defrost temperature difference threshold value indicates that the temperature of the first outdoor heat exchanger 12 is lower, and that a time interval threshold value greater than or equal to the defrost time interval threshold value indicates that there was a certain interval time from the last defrost. When the three determination targets are simultaneously satisfied, it is determined that the air conditioning system satisfies the first defrosting condition.

The three judging targets are used for judging whether to execute defrosting operation, so that the accuracy of judging the first defrosting condition can be improved, timely defrosting can be ensured when the system needs defrosting, and the influence of frequent defrosting on the performance of the whole machine can be avoided.

The specific values of the environmental temperature threshold, the defrosting temperature difference threshold and the defrosting time interval threshold are not limited, and can be set by a person skilled in the art according to actual conditions in the production and research process.

Alternatively, the above embodiment describes the defrosting process of the first outdoor heat exchanger 12, and in other possible embodiments, the air conditioning system may also defrost the second outdoor heat exchanger 22.

Specifically, the control module may be further configured to control the second four-way valve 21 to switch when the air conditioning system meets the second defrosting condition, and control the valve position of the first four-way valve 11 to remain unchanged, so that the second heat exchanger loop 2 performs defrosting operation, and the first heat exchanger loop 1 continues to perform heating operation.

The second defrosting condition may be a condition that is satisfied when the second outdoor heat exchanger 22 needs to defrost, for example, the second defrosting condition may be that the surface temperature of the second outdoor heat exchanger 22 is less than a preset temperature, but is not limited thereto, and may be set by a person skilled in the art according to actual requirements. In this embodiment, when the preset time after the defrosting of the first outdoor heat exchanger 12 is finished is reached, the control module may determine whether the system meets the second defrosting condition, and when the system meets the second defrosting condition, control the second four-way valve 21 to be placed in the refrigeration zone bit, and the first four-way valve 11 to be still placed in the heating zone bit, and may also adjust the second compressor 20 to operate at the defrosting frequency. To defrost with the second heat exchanger loop 2 and to keep the second heat exchanger loop 2 heated.

In the embodiment shown in fig. 1, when the second four-way valve 21 is reversed, the third electronic expansion valve 25 is controlled to be opened, and the high-temperature and high-pressure gaseous refrigerant compressed by the second compressor 20 in the second heat exchanger loop 2 enters the second outdoor heat exchanger 22 after passing through the second four-way valve 21, so as to heat up and defrost the second outdoor heat exchanger 22; the refrigerant then returns to the second compressor 20 through the second indoor heat exchanger 23, the second four-way valve 21, and the second gas-liquid separator 24. In the embodiment shown in fig. 2, when the second four-way valve 21 is reversed, the third electronic expansion valve 25 is controlled to be opened, and the high-temperature and high-pressure gaseous refrigerant compressed by the second compressor 20 in the second heat exchanger loop 2 enters the second outdoor heat exchanger 22 after passing through the second four-way valve 21, so as to heat up and defrost the second outdoor heat exchanger 22; the refrigerant then returns to the second compressor 20 through the first heat exchanger 4, the second indoor heat exchanger 23, the second four-way valve 21, and the second gas-liquid separator 24. In the embodiment shown in fig. 3, when the second four-way valve 21 is reversed, the fourth electronic expansion valve 28 is controlled to be closed, the fifth electronic expansion valve 29 is controlled to be opened, and the high-temperature and high-pressure gaseous refrigerant compressed by the second compressor 20 in the second heat exchanger loop 2 enters the second outdoor heat exchanger 22 after passing through the second four-way valve 21, so as to heat up and defrost the second outdoor heat exchanger 22; the refrigerant then returns to the second compressor 20 via the fifth electronic expansion valve 29, the first heat exchanger 4 and the second gas-liquid separator 24.

At the same time, the first heat exchanger loop 1 continues heating, and the control module controls the first electronic expansion valve 15 to be opened and the second electronic expansion valve 30 to be closed. The flow of refrigerant in the second heat exchanger loop 2 is as follows: the first compressor 10, the first four-way valve 11, the first indoor heat exchanger 13, the first electronic expansion valve 15, the first outdoor heat exchanger 12, the first four-way valve 11 and the first gas-liquid separator 14, and finally the gaseous refrigerant returns to the first compressor 10 and continues to circulate according to the paths.

Optionally, with continued reference to fig. 1, in a possible embodiment, the air conditioning system may further comprise a second temperature sensor 8, a first pressure sensor 91 and a second pressure sensor 92; the second temperature sensor 8 is located on the second outdoor heat exchanger 22 and is used for detecting the second temperature of the second outdoor heat exchanger 22; a first pressure sensor 91 is located in the first heat exchanger loop 1 for detecting a first pressure in the first heat exchanger loop 1 and a second pressure sensor 92 is located in the second heat exchanger loop 2 for detecting a second pressure in the second heat exchanger loop 2. The control module (not shown) is further electrically connected to the second temperature sensor 8, the first pressure sensor 91 and the second pressure sensor 92, respectively, and is further configured to determine whether the air conditioning system satisfies the second defrosting condition according to the first temperature, the second temperature, the first pressure and the second pressure.

Specifically, the second temperature sensor 8 may be disposed on the housing of the second outdoor heat exchanger 22, for detecting a second temperature (e.g., a surface temperature of the cabinet) of the second outdoor heat exchanger 22 in real time, and transmitting the second temperature to the control module. The first pressure sensor 91 may be disposed in a connection path of the first gas-liquid separator 14 and the first compressor 10, for detecting the first pressure in the first heat exchanger loop 1 in real time and transmitting the first pressure to the control module; a second pressure sensor 92 may be provided in the connection path of the second gas-liquid separator 24 and the second compressor 20 for detecting in real time the second pressure in the second heat exchanger loop 2 and sending the second pressure to the control module.

The control module obtains the second temperature based on the second temperature sensor 8, obtains the first pressure based on the first pressure sensor 91, obtains the second pressure based on the second pressure sensor 92, and determines whether the second outdoor heat exchanger 22 satisfies the second defrosting condition based on the ambient temperature, the second temperature, the defrosting time interval, the first pressure, and the second pressure together.

Further, this embodiment proposes an optional determination manner of the second defrosting condition, specifically, the second defrosting condition may include four determination targets, where the first determination target is T is equal to or less than Ta, T is an ambient temperature, ta is an ambient temperature threshold, the second determination target is T-T2 is equal to or more than Tb, T2 is a second temperature, tb is a defrosting temperature difference threshold, the third determination target is Δt is equal to or more than Δta, the fourth determination target is P1-P2 is equal to or more than Pa, P1 is a first pressure, P2 is a second pressure, and Pa is a pressure difference threshold. When the four judging targets are met at the same time, the air conditioning system can be determined to meet the second defrosting condition. The determination manners of the defrosting time interval Δt and the defrosting time interval threshold Δta may be the same as those in the above embodiment, and are the time interval threshold between the last defrosting end time of the first outdoor heat exchanger 12 (the defrosting end time of the first outdoor heat exchanger 12 not this time) and the current time.

It will be appreciated that an ambient temperature less than or equal to the ambient temperature threshold value indicates that the current air conditioning system is in a heating mode, and that a difference between the ambient temperature and the second temperature is greater than or equal to the defrost temperature difference threshold value indicates that the temperature of the second outdoor heat exchanger 22 is lower. It should be noted that in this embodiment, a pressure difference determination target is further added, and it can be understood that when the outdoor heat exchanger frosts more, the heat exchange effect of the heat exchanger is poor, the evaporation pressure is smaller, and otherwise, the evaporation pressure is larger. After defrosting of the first outdoor heat exchanger 12 is completed, the first pressure of the first heat exchanger loop 1 should be large, and at this time, if the second outdoor heat exchanger 22 is frosted seriously, the second pressure in the second heat exchanger loop 2 should be small, and the difference between the first pressure and the second pressure will be large. Therefore, when the difference between the first pressure and the second pressure is greater than or equal to the pressure difference threshold, it may be indicated that the frosting of the second outdoor heat exchanger 22 is serious, and this may be used as a fourth determination target, so that the accuracy of determining the frosting condition of the second outdoor heat exchanger 22 may be further improved. Avoiding the situation that the second outdoor heat exchanger 22 is severely frosted without entering into defrosting when the system abnormality occurs.

The specific setting of the differential pressure threshold is not limited in the embodiment of the invention, and can be set by a person skilled in the art according to actual situations in the production and development process.

Alternatively, with continued reference to FIG. 1, the first and second outdoor heat exchangers 12, 22 may be provided in a conformable manner; a fan 40 is also provided in the air conditioning system, the fan 40 being located on the side of the second outdoor heat exchanger 22 facing away from the first outdoor heat exchanger 12.

When defrosting the first outdoor heat exchanger 12, the fan 40 can be controlled to be started, and the temperature of the first outdoor heat exchanger 12 is transferred to the second outdoor heat exchanger 22 due to the fact that the first outdoor heat exchanger 12 is attached to the second indoor heat exchanger 23, so that the heat of the first outdoor heat exchanger 12 is utilized to defrost the second outdoor heat exchanger 22 at the same time. The presence of the blower 40 may accelerate the heat transfer effect between the two. With this arrangement, the number of times of defrosting the second outdoor heat exchanger 22 can be reduced, which is advantageous for saving the system power consumption.

Based on the same conception, the invention also provides a control method of the air conditioning system, which is applied to the air conditioning system provided by any embodiment of the invention, and the structure of the air conditioning system can refer to the embodiments shown in the above fig. 1 to 3, and will not be described in detail here. The control method comprises the following steps: when the air conditioning system meets the first defrosting condition, the first four-way valve 11 is controlled to change direction, and the valve position of the second four-way valve 21 is controlled to be unchanged, so that the first heat exchanger loop 1 performs defrosting operation, and the second heat exchanger loop 2 continues to perform heating operation.

The first defrosting condition may be a condition that is satisfied when the first outdoor heat exchanger 12 needs to defrost, for example, the first defrosting condition may be that the surface temperature of the first outdoor heat exchanger 12 is less than a preset temperature, but is not limited thereto, and may be set by those skilled in the art according to actual requirements. In the invention, under the heating mode of the air conditioning system, the control module can judge whether the system meets the first defrosting condition, and when the system meets the first defrosting condition, the first four-way valve 11 is controlled to be arranged at a refrigerating zone bit, the second four-way valve 21 is still arranged at a heating zone bit, and meanwhile, the first compressor 10 can be regulated to run at defrosting frequency.

Referring to fig. 1, 2 or 3, when the first four-way valve 11 is reversed, the flow direction of the refrigerant in the first heat exchanger loop 1 is changed, specifically, as follows, the high-temperature and high-pressure gaseous refrigerant compressed by the first compressor 10 passes through the first four-way valve 11 and then enters the first outdoor heat exchanger 12, the temperature of the first outdoor heat exchanger 12 is raised, the frost is formed, and the refrigerant is condensed into the high-temperature and high-pressure liquid refrigerant at the first outdoor heat exchanger 12. The refrigerant flowing out of the first outdoor heat exchanger 12 reaches the first node 1a, and at this time, the control module controls the refrigerant to enter the first sub heat exchange loop 3 and not enter the first indoor heat exchanger 13; the refrigerant entering the first sub heat exchange loop 3 flows to the second node 1b through the first heat exchanger 4, enters the first gas-liquid separator 14 through the second node 1b, and returns to the first compressor 10 for recirculation.

Because the low-temperature refrigerant in the first heat exchanger loop 1 does not flow into the first indoor heat exchanger 13 any more, but directly returns to the first gas-liquid separator 14 through the first heat exchanger 4, the low-temperature refrigerant flowing out through the first outdoor heat exchanger 12 does not influence the whole heating of the air conditioning system, the heating effect of the air conditioning system can be ensured, the continuous heating of the air conditioning system in the defrosting mode is further realized, the user use side temperature fluctuation in defrosting is avoided, and the user use comfort is improved.

The control method of the air conditioning system provided by the embodiment of the invention includes all technical features and corresponding beneficial effects of the air conditioning system provided by any embodiment of the invention, and is not repeated here. Reference is made to the above-described system embodiments for details of the corresponding embodiments of the control method.

Alternatively, with continued reference to fig. 2, the first heat exchanger 4 comprises a first fluid channel 40 and a second fluid channel 41, the first fluid channel 40 being located in the first sub heat exchange loop 3, the second fluid channel 41 being located in the connection path of the second outdoor heat exchanger 22 and the second indoor heat exchanger 23 in the second heat exchanger loop 2; the first indoor heat exchanger 13 is multiplexed into a second indoor heat exchanger 23, and the first indoor heat exchanger 13 includes a first air inlet 13a, a second air inlet 13b, a first air outlet 13c, and a second air outlet 13d; the first air inlet 13a is connected with the first node 1a, the first air outlet 13c is connected with the first four-way valve 11, the second air inlet 13b is connected with the second outdoor heat exchanger 22 through the second fluid channel 41, and the second air outlet 13d is connected with the second four-way valve 21; the air conditioning system further includes a first electronic expansion valve 15, a second electronic expansion valve 30, and a third electronic expansion valve 25, the first electronic expansion valve 15 being located in a connection path of the first outdoor heat exchanger 12 and the first air intake port 13a, the second electronic expansion valve 30 being located in a connection path of the first node 1a and the first heat exchanger 4, the third electronic expansion valve 25 being located in a connection path of the second outdoor heat exchanger 22 and the first heat exchanger 4; the control module is also electrically connected to the first electronic expansion valve 15, the second electronic expansion valve 30 and the third electronic expansion valve 25, respectively.

The control method of the air conditioning system comprises the following steps: when the air conditioning system meets the first defrosting condition, the first four-way valve 11 is controlled to change direction, the valve position of the second four-way valve 21 is kept unchanged, the first electronic expansion valve 15 is controlled to be closed, the second electronic expansion valve 30 and the third electronic expansion valve 25 are controlled to be opened, so that the first heat exchanger loop 1 performs defrosting operation, and the second heat exchanger loop 2 continues to perform heating operation.

If the control module determines that the air conditioning system meets the first defrosting condition, the first four-way valve 11 can be controlled to be switched off, and the first electronic expansion valve 15, the second electronic expansion valve 30 and the third electronic expansion valve 25 can be controlled to be switched on at the same time. So that the refrigerant flowing out of the first outdoor heat exchanger 12 enters the first sub heat exchange circuit 3 and flows into the first heat exchanger 4 through the second electronic expansion valve 30, and does not enter the first indoor heat exchanger 13 any more. Correspondingly, the circulation flow direction of the refrigerant in the second heat exchanger loop 2 is as follows: the second compressor 20, the second four-way valve 21, the second air outlet 13d of the first indoor heat exchanger 13, the second air inlet 13b of the first indoor heat exchanger 13, the first heat exchanger 4, the third electronic expansion valve 25, the second outdoor heat exchanger 22, the second four-way valve 21, and the second gas-liquid separator 24.

Optionally, with continued reference to fig. 1, the air conditioning system may further include a first temperature sensor 6 and an ambient temperature sensor 7; the first temperature sensor 6 is located on the first outdoor heat exchanger 12 for detecting a first temperature of the first outdoor heat exchanger 12, and the ambient temperature sensor 7 is for detecting an ambient temperature.

When the air conditioning system further includes the first temperature sensor 6 and the ambient temperature sensor 7, before executing the control flow in the above-described embodiment, it is also possible to execute: acquiring a first temperature and an ambient temperature based on the first temperature sensor 6 and the ambient temperature sensor 7, while acquiring a defrosting time interval; the defrosting time interval is the time interval between the ending time of the last defrosting work and the current time; and: at ambient and first temperatures and defrosting time intervals, the following are satisfied: when T is less than or equal to Ta, T-T1 is more than or equal to Tb and delta T is more than or equal to delta Ta, determining that the air conditioning system meets a first defrosting condition; wherein T is the ambient temperature, ta is the ambient temperature threshold, T1 is the first temperature, Δt is the defrosting time interval, and Δta is the defrosting time interval threshold.

Fig. 4 is a flowchart of an air conditioner control method according to an embodiment of the present invention, and referring to fig. 4, the control method includes the following steps:

S101, acquiring a first temperature and an ambient temperature based on the first temperature sensor and the ambient temperature sensor, and simultaneously acquiring a defrosting time interval.

The first temperature sensor 6 detects the first temperature of the first outdoor heat exchanger 12 in real time and transmits the first temperature to the control module; the ambient temperature sensor 7 monitors the ambient temperature in real time and transmits the ambient temperature detected in real time to the control module. Meanwhile, the control module can record the time when the last defrosting operation of the air conditioning system is finished, and further obtain the time interval between the finishing time of the last defrosting operation and the current time.

S102, at the ambient temperature and the first temperature, the defrosting time interval satisfies: and when T is less than or equal to Ta, T-T1 is less than or equal to Tb and deltat is less than or equal to deltata, determining that the air conditioning system meets the first defrosting condition.

The first defrosting condition may include three judgment targets, the first judgment target is T.ltoreq.Ta, the second judgment target is T-T1.gtoreq.Tb, and the third judgment target is Deltat.gtoreq.Deltata. When the three determination targets are simultaneously satisfied, it is determined that the air conditioning system satisfies the first defrosting condition.

And S103, when the air conditioning system meets the first defrosting condition, controlling the reversing of the first four-way valve, and controlling the valve position of the second four-way valve to be unchanged, so that the first heat exchanger loop performs defrosting operation, and the second heat exchanger loop continues to perform heating operation.

The specific implementation of this step is the same as that in the above embodiment, and will not be repeated here.

Alternatively, with continued reference to fig. 1, when the air conditioning system further includes a second temperature sensor 8, a first pressure sensor 91, and a second pressure sensor 92; the second temperature sensor 8 is located on the second outdoor heat exchanger 22 and is used for detecting the second temperature of the second outdoor heat exchanger 22; a first pressure sensor 91 is located in the first heat exchanger loop 1 for detecting a first pressure in the first heat exchanger loop 1 and a second pressure sensor 92 is located in the second heat exchanger loop 2 for detecting a second pressure in the second heat exchanger loop 2.

The control method provided by the invention can further comprise the following steps: acquiring a second temperature, a first pressure, and a second pressure based on the second temperature sensor 8, the first pressure sensor 91, and the second pressure sensor 92; when the air conditioning system meets the first defrosting condition, the reversing of the first four-way valve 11 is controlled, and the valve position of the second four-way valve 21 is controlled to be unchanged, so that the defrosting operation of the first heat exchanger loop 1 is performed, and after the heating operation of the second heat exchanger loop 2 is continuously performed, the method can further comprise the following two steps: step one: after a delay of the preset time, at the ambient temperature, the second temperature, the first pressure, the second pressure and the defrosting time interval, the following conditions are satisfied: when T is not less than Ta, T-T2 is not less than Tb, delta T is not less than delta Ta and P1-P2 is not less than Pa, determining that the air conditioning system meets a second defrosting condition; wherein T2 is the second temperature, P1 is the first pressure, P2 is the second pressure, pa is the differential pressure threshold; step two: when the air conditioning system meets the second defrosting condition, the second four-way valve 21 is controlled to change direction, and the valve position of the first four-way valve 11 is controlled to be unchanged, so that the defrosting operation is performed by the second heat exchanger loop 2, and the heating operation is continuously performed by the first heat exchanger loop 1.

Specifically, when a preset time after the end of defrosting of the first outdoor heat exchanger 12 is reached, the control module may further acquire the second temperature based on the second temperature sensor 8, acquire the first pressure based on the first pressure sensor 91, acquire the second pressure based on the second pressure sensor 92, and determine whether the second outdoor heat exchanger 22 satisfies the second defrosting condition together according to the ambient temperature, the second temperature, the defrosting time interval, the first pressure, and the second pressure.

The second defrosting condition may include four judgment targets, the first judgment target is T.ltoreq.Ta, the second judgment target is T-T2.gtoreq.Tb, the third judgment target is Deltat.gtoreq.Deltata, and the fourth judgment target is P1-P2.gtoreq.Pa. When the four judging targets are met at the same time, the air conditioning system can be determined to meet the second defrosting condition.

When the air conditioning system meets the second defrosting condition, the control module controls the first four-way valve 11 to keep the heating flag bit, and the second four-way valve 21 is switched to the refrigerating flag bit so as to utilize the second heat exchanger loop 2 to refrigerate defrosting and the first heat exchanger loop 1 to keep heating.

Further optionally, when the air conditioning system meets the first defrosting condition, the first four-way valve 11 is controlled to switch, and the valve position of the second four-way valve 21 is controlled to be unchanged, so that the first heat exchanger loop 1 performs defrosting operation, and after the second heat exchanger loop 2 continues to perform heating operation, the following steps may be further performed: when the first temperature reaches the defrosting end temperature or the defrosting duration reaches the defrosting duration threshold, the first four-way valve 11 is controlled to be commutated again, so that the first heat exchanger loop 1 continues to perform heating operation.

Specifically, in this embodiment, the defrosting end conditions may be set, and the defrosting end conditions may include: t1 is greater than or equal to Tc or t1=t2; wherein T1 is the first temperature, tc is the defrosting end temperature, T1 is the defrosting time of this time, and T2 is the defrosting duration threshold. The control module may have pre-stored therein a defrosting end temperature, i.e. the temperature at which the outdoor heat exchanger does not need to be defrosted, and a defrosting duration threshold, which may be understood as the time required to perform a defrosting operation. The defrosting end temperature and the defrosting duration threshold can be set by a person skilled in the art according to actual conditions in the production and development stage, and the invention is not limited to this and will not be repeated.

In the defrosting process of the first outdoor heat exchanger 12, the control module can switch the valve position of the first four-way valve 11 to the heating zone bit again when detecting that the air conditioning system meets any one of the defrosting end conditions, and the first heat exchanger loop 1 continues to execute the heating work.

Accordingly, the defrosting end condition of the second outdoor heat exchanger 22 can be adaptively adjusted with reference to the defrosting end condition of the first outdoor heat exchanger 12, which will not be described in detail herein.

Fig. 5 is a control logic diagram of a control method of an air conditioning system according to an embodiment of the present invention, and is described in combination with fig. 5. When the air conditioner operates in a heating mode, judging whether a first defrosting condition is met, wherein the first defrosting condition is as follows: T.ltoreq.Ta, T-T2.gtoreq.Tb and Δt.gtoreq.Δta, T, T, ta, tb and Δta are described with reference to the above examples. Further, when the first defrosting condition is met, the first compressor is controlled to operate at defrosting frequency, the first electronic expansion valve is closed, the second electronic expansion valve is opened, then the first four-way valve is reversed, the first heat exchanger loop operates in a refrigerating mode to defrost the first outdoor heat exchanger, and the second heat exchanger loop continues to heat; and if the first defrosting condition is not met, maintaining the heating operation of the first heat exchanger loop and the second heat exchanger loop. Further, judging whether a defrosting end condition is met, wherein the defrosting end condition is as follows: the description of T1 ≡ Tc or t1=t2, tc, T1 and T2 refers to the above-described embodiments. If the defrosting ending condition is met, controlling the first four-way valve to commutate again, ending defrosting by the first heat exchanger loop, and executing operation in a heating mode by the first heat exchanger loop and the second heat exchanger loop; if the defrosting condition is not met, the first heat exchanger loop continues defrosting. After the defrosting of the first heat exchanger loop is finished and the preset time is delayed, judging whether a second defrosting condition is met or not, wherein the second defrosting condition is as follows: T.ltoreq.Ta, T.gt2.gtb, Δt.gta.gta and P1-P2.gta Pa, the description of T2, P1, P2 and Pa being given with reference to the examples above. If the second defrosting condition is met, the second four-way valve is controlled to change direction, the second heat exchanger loop operates in a refrigeration mode, and the first heat exchanger loop continues to heat; and if the second defrosting condition is not met, continuing heating the second heat exchanger loop.

Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, and that various obvious changes, rearrangements, combinations, and substitutions can be made by those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.

Claims (10)

1. An air conditioning system is characterized by comprising a first heat exchanger loop, a second heat exchanger loop, a first sub heat exchange loop, a first heat exchanger and a control module;

the first heat exchanger loop comprises a first compressor, a first four-way valve, a first outdoor heat exchanger, a first indoor heat exchanger and a first gas-liquid separator which are connected with each other; the second heat exchanger loop comprises a second compressor, a second four-way valve, a second outdoor heat exchanger, a second indoor heat exchanger and a second gas-liquid separator which are connected with each other;

The first heat exchanger loop further comprises a first node and a second node, the first node is located in a connecting path of the first outdoor heat exchanger and the first indoor heat exchanger, and the second node is close to an air inlet end of the first gas-liquid separator; one end of the first sub heat exchange loop is connected to the first node, the other end of the first sub heat exchange loop is connected to the second node, and the first heat exchanger is located in the first sub heat exchange loop;

the control module is electrically connected with the first four-way valve and the second four-way valve, when the air conditioning system meets a first defrosting condition, the control module controls the first four-way valve to change direction and controls the valve position of the second four-way valve to be unchanged, so that the first heat exchanger loop performs defrosting work, and the second heat exchanger loop continues to perform heating work.

2. The air conditioning system of claim 1, wherein the first heat exchanger includes a first fluid passage and a second fluid passage, the first fluid passage being located in the first sub-heat exchange circuit, the second fluid passage being located in a connection path of the second outdoor heat exchanger and the second indoor heat exchanger in the second heat exchanger circuit;

The first indoor heat exchanger is multiplexed into the second indoor heat exchanger, and the first indoor heat exchanger comprises a first air inlet, a second air inlet, a first air outlet and a second air outlet; the first air inlet is connected with the first node, the first air outlet is connected with a first four-way valve, the second air inlet is connected with the second outdoor heat exchanger through the second fluid channel, and the second air outlet is connected with the second four-way valve;

the air conditioning system further comprises a first electronic expansion valve, a second electronic expansion valve and a third electronic expansion valve, wherein the first electronic expansion valve is positioned in a connecting path of the first outdoor heat exchanger and the first air inlet, the second electronic expansion valve is positioned in a connecting path of the first node and the first heat exchanger, and the third electronic expansion valve is positioned in a connecting path of the second outdoor heat exchanger and the first heat exchanger;

the control module is further used for controlling the first electronic expansion valve to be closed and controlling the second electronic expansion valve and the third electronic expansion valve to be opened when the air conditioning system meets the first defrosting condition.

3. The air conditioning system of claim 1, further comprising a first temperature sensor and an ambient temperature sensor; the first temperature sensor is positioned on the first outdoor heat exchanger and used for detecting the first temperature of the first outdoor heat exchanger in real time, and the environment temperature sensor is used for detecting the environment temperature in real time;

the control module is respectively and electrically connected with the first temperature sensor and the environment temperature sensor, and is further used for determining whether the air conditioning system meets the first defrosting condition according to the first temperature, the environment temperature and the defrosting time interval; the defrosting time interval is a time interval between the ending time of the last defrosting operation and the current time.

4. An air conditioning system according to claim 3, wherein the control module is further configured to control the second four-way valve to switch and control the valve position of the first four-way valve to remain unchanged when the air conditioning system satisfies a second defrosting condition, so that the second heat exchanger loop performs defrosting operation, and the first heat exchanger loop continues to perform heating operation.

5. The air conditioning system of claim 4, further comprising a second temperature sensor, a first pressure sensor, and a second pressure sensor; the second temperature sensor is positioned on the second outdoor heat exchanger and is used for detecting the second temperature of the second outdoor heat exchanger;

The first pressure sensor is positioned in the first heat exchanger loop and used for detecting first pressure in the first heat exchanger loop, and the second pressure sensor is positioned in the second heat exchanger loop and used for detecting second pressure in the second heat exchanger loop;

the control module is further electrically connected with the second temperature sensor, the first pressure sensor and the second pressure sensor respectively, and is further used for determining whether the air conditioning system meets the second defrosting condition according to the ambient temperature, the second temperature, the first pressure and the second pressure.

6. The air conditioning system of claim 1, wherein the first outdoor heat exchanger and the second outdoor heat exchanger are positioned in close proximity;

the air conditioning system further comprises a fan, wherein the fan is located at one side of the second outdoor heat exchanger, which is away from the first outdoor heat exchanger.

7. A control method of an air conditioning system, characterized by being applied to the air conditioning system according to any one of the above claims 1 to 6, comprising:

when the air conditioning system meets a first defrosting condition, the reversing of the first four-way valve is controlled, and the valve position of the second four-way valve is controlled to be unchanged, so that the defrosting work of the first heat exchanger loop is performed, and the heating work of the second heat exchanger loop is continuously performed.

8. The control method according to claim 7, wherein when the air conditioning system includes a first temperature sensor and an ambient temperature sensor;

when the air conditioning system meets the first defrosting condition, before the reversing of the first four-way valve and the valve position of the second four-way valve are controlled to be unchanged, the method further comprises the following steps:

acquiring the first temperature and the ambient temperature based on the first temperature sensor and the ambient temperature sensor, and simultaneously acquiring a defrosting time interval; the defrosting time interval is the time interval between the ending time of the last defrosting work and the current time;

at the ambient temperature and the first temperature and the defrosting time interval, the following are satisfied: when T is less than or equal to Ta, T-T1 is more than or equal to Tb and deltat is more than or equal to deltata, determining that the air conditioning system meets the first defrosting condition; wherein, T is the ambient temperature, ta is the ambient temperature threshold, T1 is the first temperature, tb is the defrosting temperature difference threshold, deltat is the defrosting time interval, and Deltata is the defrosting time interval threshold.

9. The control method of claim 8, wherein when the air conditioning system further comprises a second temperature sensor, a first pressure sensor, and a second pressure sensor;

The control method further includes:

acquiring the second temperature, the first pressure, and the second pressure based on the second temperature sensor, the first pressure sensor, and the second pressure sensor;

when the air conditioning system meets a first defrosting condition, controlling the first four-way valve to change direction, and controlling the valve position of the second four-way valve to be unchanged, so that the first heat exchanger loop performs defrosting operation, and after the second heat exchanger loop continues to perform heating operation, the air conditioning system further comprises:

after a delay of a preset time, the ambient temperature, the second temperature, the first pressure, the second pressure and the defrosting time interval satisfy: when T is not less than Ta, T-T2 is not less than Tb, delta T is not less than delta Ta and P1-P2 is not less than Pa, determining that the air conditioning system meets a second defrosting condition; wherein T2 is the second temperature, P1 is the first pressure, P2 is the second pressure, pa is a differential pressure threshold;

when the air conditioning system meets the second defrosting condition, the second four-way valve is controlled to change direction, and the valve position of the first four-way valve is controlled to be unchanged, so that the second heat exchanger loop performs defrosting operation, and the first heat exchanger loop continues to perform heating operation.

10. The control method according to claim 8, wherein when the air conditioning system satisfies a first defrosting condition, the first four-way valve is controlled to switch, and the valve position of the second four-way valve is controlled to remain unchanged, so that the first heat exchanger loop performs defrosting operation, and after the second heat exchanger loop continues to perform heating operation, further comprising:

and when the first temperature reaches the defrosting end temperature or the defrosting duration reaches the defrosting duration threshold, controlling the first four-way valve to change direction again, so that the first heat exchanger loop continues to execute heating work.