CN117006607A - Air conditioning system and defrost control method - Google Patents

Abstract

The embodiment of the application provides an air conditioning system and a defrosting control method, wherein the air conditioning system comprises a compressor, an indoor unit, an outdoor unit, a control valve group, a first circulation loop and a second circulation loop; the compressor comprises a first cylinder and a second cylinder; the indoor unit comprises a first indoor heat exchanger and a second indoor heat exchanger; the outdoor unit comprises a first outdoor heat exchanger and a second outdoor heat exchanger; the control valve group comprises a first four-way valve, a second four-way valve, a first throttling device and a second throttling device; the first cylinder, the first four-way valve, the first outdoor heat exchanger, the first throttling device and the first indoor heat exchanger are arranged on the first circulation loop; the second cylinder, the second four-way valve, the second outdoor heat exchanger, the second throttling device and the second indoor heat exchanger are arranged on the second circulation loop. The air conditioning system provided by the embodiment of the application can reduce indoor temperature fluctuation in the defrosting process.

Description

Air conditioning system and defrosting control method

Technical Field

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

Background

In a heating mode of the air conditioning system, the temperature of the refrigerant flowing through the outdoor heat exchanger is low, so that frosting of the outdoor heat exchanger is easy to occur, and the frosting can influence the heat exchange of the outdoor heat exchanger, so that the heating performance of the whole air conditioning system is influenced, and therefore, the outdoor heat exchanger needs to be defrosted.

However, in the related art, the air conditioning system generally adopts a shutdown reversing defrosting mode in a defrosting mode, and the defrosting mode can affect the indoor heating effect and further affect the comfort.

Disclosure of Invention

In view of the foregoing, it is desirable to provide an air conditioning system and a defrosting control method capable of reducing indoor temperature fluctuation during defrosting.

To achieve the above object, an embodiment of the present application provides an air conditioning system, including:

a compressor including a first cylinder and a second cylinder;

the indoor unit comprises a first indoor heat exchanger and a second indoor heat exchanger;

the outdoor unit comprises a first outdoor heat exchanger and a second outdoor heat exchanger;

the control valve group comprises a first four-way valve, a second four-way valve, a first throttling device and a second throttling device;

the first cylinder, the first four-way valve, the first outdoor heat exchanger, the first throttling device and the first indoor heat exchanger are arranged on the first circulation loop;

the second cylinder, the second four-way valve, the second outdoor heat exchanger, the second throttling device and the second indoor heat exchanger are arranged on the second circulation loop.

In one embodiment, the air conditioning system further comprises a signal valve for switching on or off the second circulation loop.

In one embodiment, the signal valve has a first working port, a second working port, and a third working port, the first cylinder having a first exhaust port and a first return port; the second cylinder is provided with an opening signal port;

the first working port is communicated with the first circulation loop between the first exhaust port and the first four-way valve, the second working port is communicated with the first circulation loop between the first air return port and the first four-way valve, and the third working port is communicated with the opening signal port.

In one embodiment, the first cylinder has a first exhaust port and a first return port, and the second cylinder has a second exhaust port and a second return port; the first cylinder is communicated with the first circulation loop through the first exhaust port and the first return port, and the second cylinder is communicated with the second circulation loop through the second exhaust port and the second return port.

In one embodiment, the first outdoor heat exchanger is located downstream of the second outdoor heat exchanger in the direction of airflow; and/or the number of the groups of groups,

The first indoor heat exchanger is located upstream of the second indoor heat exchanger in the airflow flow direction.

The embodiment of the application provides a defrosting control method, which is used for an air conditioning system, wherein the air conditioning system comprises a compressor, an indoor unit, an outdoor unit, a control valve group, a first circulation loop and a second circulation loop; the compressor comprises a first cylinder and a second cylinder; the indoor unit comprises a first indoor heat exchanger and a second indoor heat exchanger; the outdoor unit comprises a first outdoor heat exchanger and a second outdoor heat exchanger; the control valve group comprises a first four-way valve, a second four-way valve, a first throttling device and a second throttling device; the first cylinder, the first four-way valve, the first outdoor heat exchanger, the first throttling device and the first indoor heat exchanger are arranged on the first circulation loop; the second cylinder, the second four-way valve, the second outdoor heat exchanger, the second throttling device and the second indoor heat exchanger are arranged on the second circulation loop; the method comprises the following steps:

determining that the operation time of the air conditioning system in a heating mode reaches a preset time, wherein in the heating mode, the first circulation loop and the second circulation loop perform heating operation;

Acquiring a first current temperature of the second outdoor heat exchanger;

determining that a first current temperature of the second outdoor heat exchanger meets a first preset condition;

and controlling the air conditioning system to switch to a non-stop defrosting mode, and controlling the second four-way valve to change the direction so as to switch the second circulation loop from heating operation to refrigeration operation.

In one embodiment, before determining that the operation duration of the air conditioning system in the heating mode reaches the preset duration, the method further includes:

determining to enter the heating mode;

acquiring a second lowest initial temperature of the second outdoor heat exchanger in an initial operation time period;

the determining that the first current temperature of the second outdoor heat exchanger meets a first preset condition specifically includes:

a first difference between the second lowest initial temperature and a first current temperature of the second outdoor heat exchanger is determined to be greater than or equal to a first set point, wherein the first set point is greater than 0 ℃.

In one embodiment, after the non-stop defrost mode is ended, the method further comprises:

controlling the air conditioning system to switch to the heating mode;

acquiring a second current temperature of the second outdoor heat exchanger and a first current temperature of the first outdoor heat exchanger;

Determining a defrosting mode according to a second current temperature of the second outdoor heat exchanger and a first current temperature of the first outdoor heat exchanger, wherein the defrosting mode comprises a shutdown defrosting mode and a non-shutdown defrosting mode;

and controlling the air conditioning system to switch to the determined defrosting mode.

In one embodiment, the determining the defrost mode according to the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger includes:

determining that a second current temperature of the second outdoor heat exchanger meets a second preset condition;

judging whether the first current temperature of the first outdoor heat exchanger meets a third preset condition or not;

if yes, determining the defrosting mode as a shutdown defrosting mode;

if not, determining the defrosting mode as the non-stop defrosting mode.

In one embodiment, if the defrosting mode is determined to be a shutdown defrosting mode, the controlling the air conditioning system to switch to the determined defrosting mode includes:

and controlling the first four-way valve and the second four-way valve to change directions so that the first circulation loop and the second circulation loop are switched from heating operation to refrigeration operation.

In one embodiment, before determining that the operation duration of the air conditioning system in the heating mode reaches the preset duration, the method further includes:

determining to enter the heating mode;

acquiring a second lowest initial temperature of the second outdoor heat exchanger in an initial operation time period;

the determining that the second current temperature of the second outdoor heat exchanger meets a second preset condition specifically includes:

determining that a second difference between the second lowest initial temperature and a second current temperature of the second outdoor heat exchanger is greater than or equal to a second set point, wherein the second set point is greater than 0 ℃.

In one embodiment, before determining that the operation duration of the air conditioning system in the heating mode reaches the preset duration, the method further includes:

determining to enter the heating mode;

acquiring a first lowest initial temperature of the first outdoor heat exchanger in the initial operation time period;

after determining that the first current temperature of the second outdoor heat exchanger meets the first preset condition and before controlling the air conditioning system to switch to the uninterrupted defrost mode, the method further comprises:

acquiring a second current temperature of the first outdoor heat exchanger;

Recording a third difference between the first lowest initial temperature and a second current temperature of the first outdoor heat exchanger;

the judging whether the first current temperature of the first outdoor heat exchanger meets a third preset condition or not specifically comprises:

and judging whether a fourth difference value between the first lowest initial temperature and the first current temperature of the first outdoor heat exchanger is larger than or equal to the sum of the third difference value and a third set value, wherein the third set value is larger than 0 ℃.

In one embodiment, the air conditioning system further includes a signal valve for switching on or off the second circulation loop, and controlling the second four-way valve to switch the second circulation loop from a heating operation to a cooling operation, including:

controlling the signal valve to cut off the second circulation loop;

controlling the second four-way valve to be powered down;

the rotating speeds of the indoor fan and the outdoor fan are reduced;

and controlling the signal valve to conduct the second circulation loop.

In one embodiment, after entering the no-stop defrost mode, the method further comprises:

acquiring a third current temperature of the second outdoor heat exchanger;

Determining that a third current temperature of the second outdoor heat exchanger reaches a first target temperature;

and controlling the air conditioning system to switch to the heating mode.

In one embodiment, the controlling the air conditioning system to switch to a heating mode includes:

controlling the signal valve to cut off the second circulation loop;

the rotating speeds of the indoor fan and the outdoor fan are increased to the rotating speed required by heating;

controlling the signal valve to conduct the second circulation loop;

and controlling the second four-way valve to be electrified.

The embodiment of the application provides an air conditioning system and a defrosting control method, wherein the air conditioning system is provided with a first circulation loop and a second circulation loop, the first circulation loop and the second circulation loop perform heating operation in a heating mode, when a second outdoor heat exchanger needs defrosting, the second circulation loop can be controlled to be switched from heating operation to refrigerating operation, and the first circulation loop still keeps heating operation, so that the influence of the second indoor heat exchanger on indoor temperature can be reduced by utilizing the heating capacity of the first indoor heat exchanger, fluctuation of indoor temperature can be reduced, and comfort can be improved.

Drawings

Fig. 1 is a schematic structural diagram of an air conditioning system according to an embodiment of the present application, in which open arrows at an indoor unit and an outdoor unit indicate airflow directions;

fig. 2 is a schematic structural view of the air conditioning system shown in fig. 1, in which open arrows at the indoor unit and the outdoor unit indicate air flow directions, and arrows on the first circulation loop and the second circulation loop indicate flow directions of refrigerant in the non-stop defrosting mode;

FIG. 3 is a schematic diagram of a first method of defrosting control according to an embodiment of the present application;

FIG. 4 is a schematic diagram of a second method of defrosting control according to an embodiment of the present application;

FIG. 5 is a third method schematic diagram of a defrost control method according to an embodiment of the present application;

FIG. 6 is a fourth method schematic diagram of a defrost control method according to an embodiment of the present application;

fig. 7 is a schematic diagram of a fifth method of defrosting control method according to an embodiment of the present application;

fig. 8 is a flowchart of a defrosting control method according to an embodiment of the present application.

Description of the reference numerals

A compressor 10; opening the signal port 11; a first return port 12; a second return port 13; a first exhaust port 14; a second exhaust port 15; an indoor unit 20; a first indoor heat exchanger 21; a second indoor heat exchanger 22; an outdoor unit 30; the first outdoor heat exchanger 31; the second outdoor heat exchanger 32; a control valve group 40; a first four-way valve 41; a second four-way valve 42; a first throttle device 43; a second restriction 44; a first circulation loop 50; a second circulation loop 60; a signal valve 70; a first work port 71; a second working port 72; a third working port 73; a first temperature sensor 80; a second temperature sensor 90.

Detailed Description

It should be noted that, in the case of no conflict, the embodiments of the present application and the technical features of the embodiments may be combined with each other, and the detailed description in the specific embodiments should be interpreted as an explanation of the gist of the present application and should not be construed as unduly limiting the present application.

In the description of the present application, min represents time unit minutes, s represents time unit seconds, and DEG C represents temperature unit DEG C.

An embodiment of the present application provides an air conditioning system, referring to fig. 1, which includes a compressor 10, an indoor unit 20, a control valve group 40, a first circulation loop 50, and a second circulation loop 60.

The compressor 10 includes a first cylinder and a second cylinder, that is, the compressor 10 has at least two cylinders. The first cylinder shown in fig. 1 has a first exhaust port 14 and a first return port 12, and the second cylinder has a second exhaust port 15 and a second return port 13, that is, the first cylinder and the second cylinder have separate exhaust ports and return ports, respectively, or the compressor 10 may be a double suction double row compressor 10.

In some embodiments, the first cylinder and the second cylinder may share the same exhaust port, for example, the gas discharged from the first cylinder and the gas discharged from the second cylinder may be mixed in the compressor 10 and then discharged through the same exhaust port.

The indoor unit 20 includes a first indoor heat exchanger 21 and a second indoor heat exchanger 22, that is, the indoor unit 20 is provided with at least two heat exchangers.

The outdoor unit 30 includes a first outdoor heat exchanger 31 and a second outdoor heat exchanger 32, that is, the outdoor unit 30 is also provided with at least two heat exchangers.

The control valve block 40 includes a first four-way valve 41, a second four-way valve 42, a first throttle device 43, and a second throttle device 44.

The first cylinder, the first four-way valve 41, the first outdoor heat exchanger 31, the first throttle device 43, and the first indoor heat exchanger 21 are disposed on the first circulation loop 50, that is, the first outdoor heat exchanger 31 and the first indoor heat exchanger 21 are used in cooperation.

The second cylinder, the second four-way valve 42, the second outdoor heat exchanger 32, the second throttling device 44 and the second indoor heat exchanger 22 are arranged on the second circulation loop 60, that is, the second outdoor heat exchanger 32 and the second indoor heat exchanger 22 are matched for use, which is equivalent to that the first circulation loop 50 and the second circulation loop 60 are two mutually independent circulation loops.

The first circulation loop 50 and the second circulation loop 60 may perform a cooling or heating operation, respectively.

Taking the air conditioning system shown in fig. 1 as an example, the circulation route of the first circulation circuit 50 at the time of cooling operation is: the refrigerant with high temperature and high pressure is discharged from the first exhaust port 14 of the first cylinder, enters the D port of the first four-way valve 41, flows out from the C port of the first four-way valve 41 into the first outdoor heat exchanger 31, flows out of the first outdoor heat exchanger 31 from the first outdoor heat exchanger 31 after the refrigerant subjected to heat exchange in the first outdoor heat exchanger 31, enters the first indoor heat exchanger 21 through the first throttling device 43 to exchange heat, flows out of the first indoor heat exchanger 21 after the refrigerant subjected to heat exchange flows out of the first indoor heat exchanger 21, flows back to the E port of the first four-way valve 41, flows from the S port of the first four-way valve 41 to the first return port 12 of the first cylinder, and flows back into the first cylinder from the first return port 12, thereby completing one refrigeration cycle.

Referring to fig. 1, the second circulation loop 60 has a circulation route during the cooling operation: the refrigerant with high temperature and high pressure is discharged from the second exhaust port 15 of the second cylinder, enters the D port of the second four-way valve 42, flows out from the C port of the second four-way valve 42 into the second outdoor heat exchanger 32, flows out of the second outdoor heat exchanger 32 from the second outdoor heat exchanger 32 after the refrigerant subjected to heat exchange in the second outdoor heat exchanger 32, enters the second indoor heat exchanger 22 through the second throttling device 44 to exchange heat, flows out of the second indoor heat exchanger 22 after the refrigerant subjected to heat exchange flows out of the second indoor heat exchanger 22, flows back to the E port of the second four-way valve 42, flows from the S port of the second four-way valve 42 to the second air return port 13 of the second cylinder, and flows back into the second cylinder from the second air return port 13, thereby completing one refrigeration cycle.

Referring to fig. 1, the first circulation loop 50 has a circulation route during the heating operation: the refrigerant with high temperature and high pressure is discharged from the first exhaust port 14 of the first cylinder, enters the port D of the first four-way valve 41, flows out of the port E of the first four-way valve 41 into the first indoor heat exchanger 21, flows out of the first indoor heat exchanger 21 after the refrigerant subjected to heat exchange in the first indoor heat exchanger 21, enters the first outdoor heat exchanger 31 through the first throttling device 43 to exchange heat, flows out of the first outdoor heat exchanger 31 after the refrigerant subjected to heat exchange, flows back to the port C of the first four-way valve 41, flows from the port S of the first four-way valve 41 to the first return port 12 of the first cylinder, and flows back into the first cylinder from the first return port 12, thereby completing one heating cycle.

Referring to fig. 1, the second circulation loop 60 has a circulation route during the heating operation: the refrigerant with high temperature and high pressure is discharged from the second exhaust port 15 of the second cylinder, enters the port D of the second four-way valve 42, flows out of the port E of the second four-way valve 42 into the second indoor heat exchanger 22, flows out of the second indoor heat exchanger 22 after the refrigerant subjected to heat exchange in the second indoor heat exchanger 22 flows out of the second indoor heat exchanger 22, enters the second outdoor heat exchanger 32 through the second throttling device 44 to exchange heat, flows out of the second outdoor heat exchanger 32 after the refrigerant subjected to heat exchange, flows back to the port C of the second four-way valve 42, flows from the port S of the second four-way valve 42 to the second air return port 13 of the second cylinder, and flows back into the second cylinder from the second air return port 13, thereby completing one heating cycle.

It should be noted that, the above-mentioned circulation route is mainly used for explaining the flowing direction of the refrigerant, and various physical changes occurring when the refrigerant circulates in the circulation route belong to common knowledge in the art, and are not described herein.

Still another embodiment of the present application provides a defrosting control method for an air conditioning system according to any one of the embodiments of the present application, referring to fig. 3, the defrosting control method mainly includes the following steps:

Step S101, determining that the operation time length of the air conditioning system in a heating mode reaches a preset time length, wherein in the heating mode, the first circulation loop and the second circulation loop perform heating operation;

and in the heating mode, the first four-way valve and the second four-way valve are electrified, and the first indoor heat exchanger and the second indoor heat exchanger are used for heating the indoor space.

The operation time length refers to the operation time length of the air conditioning system in the heating mode, namely, the operation time length of the first circulation loop and the second circulation loop in the heating operation.

The value of the preset time period may be determined according to needs, and the preset time period may be, for example, 20min to 50min, and more preferably, 30min.

Step S102, acquiring a first current temperature of a second outdoor heat exchanger;

specifically, the first current temperature of the second outdoor heat exchanger is a temperature reached by the second outdoor heat exchanger when an operation time period of the air conditioning system in a heating mode reaches a preset time period.

Referring to fig. 1, a second temperature sensor 90 may be disposed on the second outdoor heat exchanger 32, and the first current temperature of the second outdoor heat exchanger 32 is obtained through the second temperature sensor 90.

Step S103, determining that the first current temperature of the second outdoor heat exchanger meets a first preset condition;

and step S104, controlling the air conditioning system to switch to a non-stop defrosting mode, and controlling the second four-way valve to change the direction so as to switch the second circulation loop from heating operation to cooling operation.

Specifically, when the first current temperature of the second outdoor heat exchanger meets the first preset condition, it indicates that the first current temperature of the second outdoor heat exchanger is lower, and defrosting of the second outdoor heat exchanger is required, at this time, the air conditioning system may be switched from the heating mode to the non-stop defrosting mode, referring to fig. 2, by controlling the reversing of the second four-way valve 42, the second circulation loop 60 is switched from the heating operation to the cooling operation, which is equivalent to that the refrigerant circulating along the second circulation loop 60 releases heat when flowing through the second outdoor heat exchanger 32, so that the second outdoor heat exchanger 32 heats up and defrosts, and meanwhile, the first circulation loop 50 still keeps the heating operation, which is equivalent to that the first indoor heat exchanger 21 keeps heating the room.

It should be noted that, if the first current temperature of the second outdoor heat exchanger does not meet the first preset condition, the heating mode may be continuously maintained, the operation duration of the air conditioning system in the heating mode is recalculated, and when the duration of the air conditioning system reaches the preset duration again, the step S101 is executed again, which is equivalent to that before entering the non-stop defrosting mode, the judgment may be performed once every preset duration.

In the related art, the air conditioning system generally adopts shutdown reversing defrosting in a defrosting mode, and in the defrosting process, the indoor heat exchanger cannot heat the indoor space, and even a small amount of cold air flows into the indoor space, so that the indoor temperature can be reduced, and the comfort is further affected.

In the air conditioning system provided by the embodiment of the application, the first circulation loop and the second circulation loop are arranged, and both the first circulation loop and the second circulation loop perform heating operation in a heating mode, when the second outdoor heat exchanger needs defrosting, the second circulation loop can be controlled to switch from heating operation to cooling operation, and the first circulation loop still maintains the heating operation, so that the influence of the second indoor heat exchanger on the indoor temperature can be reduced by utilizing the heating capacity of the first indoor heat exchanger, and therefore, the fluctuation of the indoor temperature can be reduced, and the comfort can be improved.

In addition, referring to fig. 1, the first outdoor heat exchanger 31 may be disposed downstream of the second outdoor heat exchanger 32 in the airflow direction, that is, the airflow generated by the outdoor fan flows through the second outdoor heat exchanger 32 first and then through the first outdoor heat exchanger 31, which corresponds to the second outdoor heat exchanger 32 being disposed on the windward side, if necessary. When the outdoor unit 30 heats and frosts in winter, the frost layer is mostly located on the windward side of the heat exchanger, so that the second outdoor heat exchanger 32 is arranged on the windward side, and the frost layer can be mainly concentrated on the second outdoor heat exchanger 32, thereby being more beneficial to realizing defrosting without stopping.

Referring to fig. 1, if necessary, the first indoor heat exchanger 21 may be disposed upstream of the second indoor heat exchanger 22 along the airflow direction, that is, the airflow generated by the indoor fan flows through the first indoor heat exchanger 21 and then flows through the second indoor heat exchanger 22, which is equivalent to the first indoor heat exchanger 21 being disposed on the windward side, so that in the defrosting mode without shutdown, the hot airflow generated by the first indoor heat exchanger 21 may be blown to the second indoor heat exchanger 22, thereby raising the temperature of the second indoor heat exchanger 22 and shortening the defrosting time.

In some embodiments, the first outdoor heat exchanger 31 may be disposed upstream of the second outdoor heat exchanger 32 in the airflow direction, or the first indoor heat exchanger 21 may be disposed downstream of the second indoor heat exchanger 22 in the airflow direction.

In one embodiment, referring to fig. 1, the air conditioning system may be provided with a signal valve 70, where the signal valve 70 is used to turn on or off the second circulation loop 60, that is, the signal valve 70 may be used to control the operation of the second circulation loop 60. Accordingly, referring to fig. 4, controlling the reversing of the second four-way valve to switch the second circulation loop from the heating operation to the cooling operation includes:

Step S1041: the control signal valve cuts off the second circulation loop;

step S1042: controlling the second four-way valve to be powered down;

step S1043: the rotating speeds of the indoor fan and the outdoor fan are reduced;

step S1044: the control signal valve conducts the second circulation loop.

Step S1042 and step S1043 are not sequential.

That is, after entering the non-stop defrosting mode, the second circulation loop 60 is cut off by the control signal valve 70, so that the refrigerant in the second circulation loop 60 stops circulating, and the pressures of the high pressure side and the low pressure side of the second circulation loop 60 reach balance, after the second circulation loop 60 is cut off, a certain period of time, for example, 30s, can be waited, then the second four-way valve 42 is controlled to be powered down, the second four-way valve 42 is switched over, and the rotation speeds of the indoor fan and the outdoor fan are controlled to be reduced, so as to reduce the air quantity, wherein the rotation speed reduction values of the indoor fan and the outdoor fan can be determined according to requirements, and more preferably, the rotation speeds of the indoor fan and the outdoor fan can be reduced to the minimum rotation speeds. Finally, the control signal valve 70 conducts the second circulation loop 60 to switch the second circulation loop 60 to the cooling operation.

The signal valve 70 may be disposed in various manners, for example, referring to fig. 1, the signal valve 70 has a first working port 71, a second working port 72, and a third working port 73, and for example, the signal valve 70 may be a three-way valve. The first cylinder has a first exhaust port 14 and a first return port 12; the second cylinder is provided with an opening signal port 11; the first working port 71 communicates with the first circulation circuit 50 between the first exhaust port 14 and the first four-way valve 41, the second working port 72 communicates with the first circulation circuit 50 between the first return port 12 and the first four-way valve 41, and the third working port 73 communicates with the opening signal port 11.

Specifically, when the signal valve 70 is powered down, the second circulation circuit 60 is in a conductive state, and when the signal valve 70 is powered up, a flow path between the second working port 72 and the third working port 73 is conductive, and the high pressure of the second cylinder is released, whereby the second circulation circuit 60 can be shut off.

In one embodiment, before determining that the operation duration reaches the preset duration, the method further includes: determining to enter a heating mode; a second minimum initial temperature of the second outdoor heat exchanger during an initial operating period is obtained.

The second lowest initial temperature refers to a temperature minimum value of the second outdoor heat exchanger during an initial certain operation period (i.e., initial operation period) after entering the heating mode.

The initial operation period may be determined as needed, and may be, for example, a period of 7min to 12min after entering the heating mode.

Referring to fig. 1, a second minimum initial temperature may also be obtained by the second temperature sensor 90.

In addition, the first preset time period may be a time period calculated after the initial operation period, for example, the first preset time period may be calculated from 13 th minute. Alternatively, the initial operation period may be included in a first preset period, for example, the first preset period may be calculated after the air conditioning system enters the heating mode, and assuming that the preset period is 30min, the initial operation period is a period from 7min to 12min after the air conditioning system enters the heating mode, the 30min after the air conditioning system enters the heating mode is a time point when the first current temperature of the second outdoor heat exchanger is obtained for the first time, and the period from 7min to 12min after the air conditioning system enters the heating mode is a time period when the second lowest initial temperature is obtained.

Further, determining that the first current temperature of the second outdoor heat exchanger meets the first preset condition may be:

a first difference between the second lowest initial temperature and a first current temperature of the second outdoor heat exchanger is determined to be greater than or equal to a first set point, wherein the first set point is greater than 0 ℃.

Specifically, the second lowest initial temperature is denoted by TCb0, the first current temperature of the second outdoor heat exchanger is denoted by TCb1, and the first set value is denoted by S1, and the first preset condition may be that the second lowest initial temperature TCb0, the first current temperature TCb1 of the second outdoor heat exchanger, and the first set value S1 satisfy the following conditions: TCb0-TCb 1. Gtoreq.S1, wherein the value of S1 can be determined as desired, e.g., S1 can be 1℃to 5℃and more preferably S1 can be 2 ℃. If TCb0-TCb1 is greater than or equal to S1, then the first current temperature of the second outdoor heat exchanger is lower than the second lowest initial temperature of the second outdoor heat exchanger in the initial operation period, and the second outdoor heat exchanger needs to defrost, so that a non-stop defrosting mode can be entered.

In some embodiments, the first difference between the second lowest initial temperature and the first current temperature of the second outdoor heat exchanger may be greater than the first set value, that is, the second lowest initial temperature TCb0, the first current temperature TCb1 of the second outdoor heat exchanger, and the first set value S1 satisfy: TCb0-TCb1 & gt S1.

In one embodiment, referring to fig. 5, after the non-stop defrosting mode is finished, the method further includes:

step S105: controlling the air conditioning system to switch to a heating mode;

that is, the air conditioning system enters a normal heating mode again for heating.

For example, after entering the non-stop defrosting mode, the third current temperature of the second outdoor heat exchanger may be obtained, and the third current temperature may be obtained in real time, or may be obtained once every certain period of time, where TCb3 represents the third current temperature of the second outdoor heat exchanger, T represents the first target temperature, and when it is determined that the third current temperature TCb3 of the second outdoor heat exchanger reaches the first target temperature T1, that is, TCb3 is greater than or equal to T1, it indicates that the temperature of the second outdoor heat exchanger has risen to a suitable temperature, and no defrosting needs to be continued, and at this time, the air conditioning system may be controlled to switch from the non-stop defrosting mode to the heating mode.

The value of T1 may be determined as desired, for example, T1 may be 5℃to 15℃and more preferably T1 may be 8 ℃.

Referring to fig. 6, taking an air conditioning system with a signal valve as an example, controlling the air conditioning system to switch to a heating mode includes:

step S1051: the control signal valve cuts off the second circulation loop;

Step S1052: the rotational speeds of the indoor fan and the outdoor fan are increased to the rotational speed required by heating;

step S1053: the control signal valve conducts the second circulation loop;

step S1054: and controlling the second four-way valve to be electrified.

That is, the second circulation loop can be cut off through the control signal valve, so that the refrigerant in the second circulation loop stops circulating flow, then the rotational speeds of the indoor fan and the outdoor fan are both increased to the normal rotational speed required by heating, after the rotational speeds of the indoor fan and the outdoor fan reach the normal rotational speed required by heating, a certain period of time can be waited, for example, 20s, the control signal valve is controlled to conduct the second circulation loop, finally the second four-way valve is controlled to be electrified, the second four-way valve is switched, after the second four-way valve is switched, the second circulation loop is switched from the refrigerating operation to the heating operation, which is equivalent to the air conditioning system being switched from the non-stop defrosting mode to the heating mode.

Step S106: acquiring a second current temperature of a second outdoor heat exchanger and a first current temperature of the first outdoor heat exchanger;

the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger are temperatures reached by the second outdoor heat exchanger and the first outdoor heat exchanger at a certain time point after the air conditioning system is switched from the non-stop defrosting mode to the heating mode, and the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger can be obtained in real time or can be obtained once every a certain time period. The time point at which the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger are acquired may be the same or different.

Referring to fig. 1, a first temperature sensor 80 may be disposed on the first outdoor heat exchanger 31, and a first current temperature of the first outdoor heat exchanger 31 is obtained through the first temperature sensor 80.

Step S107: determining a defrosting mode according to the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger, wherein the defrosting mode comprises a shutdown defrosting mode and a non-shutdown defrosting mode;

that is, the defrosting mode of the air conditioning system may include at least two modes of a shutdown defrosting mode and a non-shutdown defrosting mode, and accordingly, which defrosting mode is to be selected next may be determined according to the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger.

Step S108: and controlling the air conditioning system to switch to the determined defrosting mode.

Illustratively, referring to fig. 7, determining the defrost mode from the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger may include the steps of:

step S1071: determining that a second current temperature of the second outdoor heat exchanger meets a second preset condition;

there may be various ways of determining that the second current temperature of the second outdoor heat exchanger satisfies the second preset condition, and the second preset condition may be, for example, determining that a second difference between the second lowest initial temperature and the second current temperature of the second outdoor heat exchanger is greater than or equal to a second set value, wherein the second set value is greater than 0 ℃.

Specifically, TCb2 represents a second current temperature of the second outdoor heat exchanger, S2 represents a second set value, and the second preset condition may be that the second minimum initial temperature TCb0, the second current temperature TCb2 of the second outdoor heat exchanger, and the second set value S2 satisfy: TCb0-TCb 2. Gtoreq.S2, wherein the value of S2 can be determined as desired, e.g., S2 can be 1℃to 5℃and more preferably S2 can be 2 ℃. If TCb0-TCb 2. Gtoreq.S 2, it indicates that the second current temperature of the second outdoor heat exchanger is lower than the second lowest initial temperature of the second outdoor heat exchanger during the initial operating period, and that the second outdoor heat exchanger needs to be defrosted.

In some embodiments, the second difference between the second lowest initial temperature and the second current temperature of the second outdoor heat exchanger may be greater than the second set value, that is, the second lowest initial temperature TCb0, the second current temperature TCb2 of the second outdoor heat exchanger, and the second set value S2 satisfy: TCb0-TCb2 > S2.

Step S1072: judging whether the first current temperature of the first outdoor heat exchanger meets a third preset condition or not;

the manner of determining whether the first current temperature of the first outdoor heat exchanger satisfies the third preset condition may be various, and for example, when the second lowest initial temperature of the second outdoor heat exchanger in the initial operation period is obtained, the first lowest initial temperature of the first outdoor heat exchanger in the initial operation period may also be obtained.

Accordingly, after determining that the first current temperature of the second outdoor heat exchanger meets the first preset condition, and before controlling the air conditioning system to switch to the non-stop defrost mode, the method further includes: acquiring a second current temperature of the first outdoor heat exchanger; a third difference between the first lowest initial temperature and the second current temperature of the first outdoor heat exchanger is recorded.

The second current temperature of the first outdoor heat exchanger is a temperature of the first outdoor heat exchanger acquired during a period of time before it is determined that the first current temperature of the second outdoor heat exchanger satisfies the first preset condition and the air conditioning system is switched to the non-stop defrost mode. That is, if it is determined to switch to the non-stop defrost mode, a third difference between the first lowest initial temperature and the second current temperature of the first outdoor heat exchanger may be recorded prior to the switching.

Let TCa0 denote the first lowest initial temperature, TCa2 denote the second current temperature of the second outdoor heat exchanger, Δt denote the third difference, and Δt=tca0-TCa 2, i.e. the value of Δt is recorded.

Further, whether the first current temperature of the first outdoor heat exchanger meets a third preset condition is judged, specifically: and judging whether a fourth difference value between the first lowest initial temperature and the first current temperature of the first outdoor heat exchanger is larger than or equal to the sum of a third difference value and a third set value, wherein the third set value is larger than 0 ℃.

Specifically, the first current temperature of the first outdoor heat exchanger is denoted by TCa1, and the third set value is denoted by S3, the above determination may be expressed as: judging whether the first lowest initial temperature TCa0 and the first current temperature TCa1 of the first outdoor heat exchanger satisfy: TCa 0-TCa1.gtoreq.DELTA.T+S3, wherein the value of S3 can be determined as desired, e.g., S3 can be 1℃to 5℃and more preferably S3 can be 2 ℃.

In another embodiment, it may also be determined whether the first minimum initial temperature TCa0 and the first current temperature TCa1 of the first outdoor heat exchanger satisfy: TCa0-TCa1 & gt (. DELTA.T+S3).

Step S1073: if yes, determining that the defrosting mode is a shutdown defrosting mode;

if the first current temperature of the first outdoor heat exchanger meets the third preset condition, the first current temperature of the first outdoor heat exchanger is lower, and defrosting of the first outdoor heat exchanger is needed.

For example, if the defrosting mode is determined to be the shutdown defrosting mode, the first circulation loop and the second circulation loop can both perform cooling operation by controlling the reversing of the first four-way valve and the second four-way valve so as to defrost the first outdoor heat exchanger and the second outdoor heat exchanger.

Illustratively, the manner of controlling the reversing of the first four-way valve and the second four-way valve may be: and (3) closing the compressor, waiting for a certain period of time, for example, after 30 seconds, controlling the first four-way valve and the second four-way valve to be powered off, closing the outdoor fan, waiting for a certain period of time, for example, after 10 seconds, starting the compressor, and closing the indoor fan.

In addition, after entering the shutdown defrosting mode, the third current temperature of the first outdoor heat exchanger and the fourth current temperature of the second outdoor heat exchanger can be obtained, and whether the third current temperature of the first outdoor heat exchanger reaches the second target temperature or not and whether the fourth current temperature of the second outdoor heat exchanger reaches the third target temperature or not is judged. The third current temperature of the first outdoor heat exchanger and the fourth current temperature of the second outdoor heat exchanger can be obtained in real time, or can be obtained once every certain time, TCa3 is used for representing the third current temperature of the first outdoor heat exchanger, TCb4 is used for representing the fourth current temperature of the second outdoor heat exchanger, T2 is used for representing the second target temperature, T3 is used for representing the third target temperature, when the third current temperature TCa3 of the first outdoor heat exchanger is determined to reach the second target temperature T2, the fourth current temperature TCb4 of the second outdoor heat exchanger reaches the third target temperature T3, namely TCa3 is larger than or equal to T2, and TCb4 is larger than or equal to T3, the temperatures of the first outdoor heat exchanger and the second outdoor heat exchanger are both increased to proper temperatures, and the defrosting is not required to be continued.

The values of T2 and T3 may be determined as desired, e.g., T2 may be 5℃ to 15℃, more preferably T2 may be 8℃, T3 may be 5℃ to 15℃, more preferably T3 may also be 8℃, that is, T1, T2 and T3 may take the same values.

The compressor may be turned off after stopping defrosting, the outdoor fan may be turned on, and the first four-way valve and the second four-way valve may be controlled to be powered on after a certain period of time, for example, after 10s, and the compressor may be turned on after a certain period of time, for example, after 10s, so that the indoor fan may work according to a normal cold air preventing program.

Step S1074: if not, determining that the defrosting mode is a non-stop defrosting mode.

That is, if the first current temperature of the first outdoor heat exchanger does not meet the third preset condition, the air conditioning system may be controlled to switch to the non-stop defrosting mode, that is, only the second outdoor heat exchanger is defrosted, while the first circulation loop still maintains the heating operation.

Referring to fig. 8, a defrosting control method according to the present application is described below, and includes the following steps:

step S201: determining to enter a heating mode;

in a heating mode, the first circulation loop and the second circulation loop perform heating operation;

Step S202: acquiring a first lowest initial temperature TCa0 of the first outdoor heat exchanger in an initial operation time period and a second lowest initial temperature TCb0 of the second outdoor heat exchanger in the initial operation time period;

step S203: determining that the operation time length reaches a preset time length t;

step S204: acquiring a first current temperature TCb1 of the second outdoor heat exchanger;

step S205: judging whether the second lowest initial temperature TCb0, the first current temperature TCb1 of the second outdoor heat exchanger and the first set value S1 satisfy: TCb0-TCb1 is greater than or equal to S1, if yes, executing step S206, if no, executing step S204;

step S206: acquiring a second current temperature TCa2 of the first outdoor heat exchanger;

step S207: recording a third difference Δt between the first lowest initial temperature TCa0 and the second current temperature TCa2 of the first outdoor heat exchanger, i.e., recording Δt=tca0-tca2;

step S208: switching to a non-stop defrosting mode;

step S209: acquiring a third current temperature TCb3 of the second outdoor heat exchanger;

step S210: judging whether the third current temperature TCb3 of the second outdoor heat exchanger reaches the first target temperature T1, namely, whether: TCb3 is greater than or equal to T1, if yes, execute step S211, if no, execute step S209;

Step S211: switching to a heating mode;

step S212: acquiring a second current temperature TCb2 of the second outdoor heat exchanger and a first current temperature TCa1 of the first outdoor heat exchanger;

step S213: judging whether the second lowest initial temperature TCb0, the second current temperature TCb2 of the second outdoor heat exchanger and the second set value S2 satisfy: TCb0-TCb2 is greater than or equal to S2, if yes, executing step S214, if no, executing step S212;

that is, step S213 is to determine whether the second current temperature TCb2 of the second outdoor heat exchanger satisfies the second preset condition.

In addition, in some embodiments, step S212 may also obtain only the second current temperature TCb2 of the second outdoor heat exchanger, and if the condition of step S213 is satisfied, then obtain the first current temperature TCa1 of the first outdoor heat exchanger.

Step S214: judging whether the first lowest initial temperature TCa0, the first current temperature TCa1 of the first outdoor heat exchanger, the third difference Δt and the third set value S3 satisfy: TCa0-TCa1 is not less than (DeltaT+S3), if yes, executing step S215, otherwise, executing step S208;

that is, step S214 is to determine whether the first current temperature of the first outdoor heat exchanger satisfies the third preset condition.

Step S215: switching to a shutdown defrosting mode;

step S216: acquiring a third current temperature TCa3 and a fourth current temperature TCb4 of the first outdoor heat exchanger;

step S217: judging whether the third current temperature TCa3 of the first outdoor heat exchanger reaches the second target temperature T2 or not, and whether the fourth current temperature TCb4 of the second outdoor heat exchanger reaches the third target temperature T3 or not, namely, whether TCa3 is more than or equal to T2 or not is met, and whether TCb4 is more than or equal to T3 or not, if yes, executing step S218, and if not, executing step S216;

step S218: switching to a heating mode;

step S219: and (5) ending.

The various embodiments/implementations provided by the application may be combined with one another without contradiction.

The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims (15)

1. An air conditioning system, comprising:

a compressor including a first cylinder and a second cylinder;

the indoor unit comprises a first indoor heat exchanger and a second indoor heat exchanger;

The outdoor unit comprises a first outdoor heat exchanger and a second outdoor heat exchanger;

the control valve group comprises a first four-way valve, a second four-way valve, a first throttling device and a second throttling device;

the first cylinder, the first four-way valve, the first outdoor heat exchanger, the first throttling device and the first indoor heat exchanger are arranged on the first circulation loop;

the second cylinder, the second four-way valve, the second outdoor heat exchanger, the second throttling device and the second indoor heat exchanger are arranged on the second circulation loop.

2. The air conditioning system of claim 1, further comprising a signal valve for switching on or off the second circulation loop.

3. The air conditioning system of claim 2, wherein the signal valve has a first working port, a second working port, and a third working port, the first cylinder having a first exhaust port and a first return port; the second cylinder is provided with an opening signal port;

the first working port is communicated with the first circulation loop between the first exhaust port and the first four-way valve, the second working port is communicated with the first circulation loop between the first air return port and the first four-way valve, and the third working port is communicated with the opening signal port.

4. The air conditioning system of claim 1, wherein the first cylinder has a first exhaust port and a first return port, and the second cylinder has a second exhaust port and a second return port; the first cylinder is communicated with the first circulation loop through the first exhaust port and the first return port, and the second cylinder is communicated with the second circulation loop through the second exhaust port and the second return port.

5. The air conditioning system of claim 1, wherein the first outdoor heat exchanger is located downstream of the second outdoor heat exchanger in the direction of airflow; and/or the number of the groups of groups,

the chamber first indoor heat exchanger is located upstream of the second indoor heat exchanger in the direction of airflow.

6. A defrosting control method for an air conditioning system, which is characterized in that the air conditioning system comprises a compressor, an indoor unit, an outdoor unit, a control valve group, a first circulation loop and a second circulation loop; the compressor comprises a first cylinder and a second cylinder; the indoor unit comprises a first indoor heat exchanger and a second indoor heat exchanger; the outdoor unit comprises a first outdoor heat exchanger and a second outdoor heat exchanger; the control valve group comprises a first four-way valve, a second four-way valve, a first throttling device and a second throttling device; the first cylinder, the first four-way valve, the first outdoor heat exchanger, the first throttling device and the first indoor heat exchanger are arranged on the first circulation loop; the second cylinder, the second four-way valve, the second outdoor heat exchanger, the second throttling device and the second indoor heat exchanger are arranged on the second circulation loop; the method comprises the following steps:

Determining that the operation time of the air conditioning system in a heating mode reaches a preset time, wherein in the heating mode, the first circulation loop and the second circulation loop perform heating operation;

acquiring a first current temperature of the second outdoor heat exchanger;

determining that a first current temperature of the second outdoor heat exchanger meets a first preset condition;

and controlling the air conditioning system to switch to a non-stop defrosting mode, and controlling the second four-way valve to change the direction so as to switch the second circulation loop from heating operation to refrigeration operation.

7. The defrost control method according to claim 6, wherein before determining that the operation time period of the air conditioning system in the heating mode reaches a preset time period, the method further comprises:

determining to enter the heating mode;

acquiring a second lowest initial temperature of the second outdoor heat exchanger in an initial operation time period;

the determining that the first current temperature of the second outdoor heat exchanger meets a first preset condition specifically includes:

a first difference between the second lowest initial temperature and a first current temperature of the second outdoor heat exchanger is determined to be greater than or equal to a first set point, wherein the first set point is greater than 0 ℃.

8. The defrost control method of claim 6, wherein after the non-stop defrost mode is ended, the method further comprises:

controlling the air conditioning system to switch to the heating mode;

acquiring a second current temperature of the second outdoor heat exchanger and a first current temperature of the first outdoor heat exchanger;

determining a defrosting mode according to a second current temperature of the second outdoor heat exchanger and a first current temperature of the first outdoor heat exchanger, wherein the defrosting mode comprises a shutdown defrosting mode and a non-shutdown defrosting mode;

and controlling the air conditioning system to switch to the determined defrosting mode.

9. The defrost control method of claim 8, wherein the determining a defrost mode based on the second current temperature of the second outdoor heat exchanger and the first current temperature of the first outdoor heat exchanger comprises:

determining that a second current temperature of the second outdoor heat exchanger meets a second preset condition;

judging whether the first current temperature of the first outdoor heat exchanger meets a third preset condition or not;

if yes, determining the defrosting mode as a shutdown defrosting mode;

if not, determining the defrosting mode as the non-stop defrosting mode.

10. The defrost control method according to claim 8, wherein if it is determined that the defrost mode is a stop defrost mode, the controlling the air conditioning system to switch to the determined defrost mode comprises:

and controlling the first four-way valve and the second four-way valve to change directions so that the first circulation loop and the second circulation loop are switched from heating operation to refrigeration operation.

11. The defrost control method according to claim 9, wherein before determining that the operation time period of the air conditioning system in the heating mode reaches a preset time period, the method further comprises:

determining to enter the heating mode;

acquiring a second lowest initial temperature of the second outdoor heat exchanger in an initial operation time period;

the determining that the second current temperature of the second outdoor heat exchanger meets a second preset condition specifically includes:

determining that a second difference between the second lowest initial temperature and a second current temperature of the second outdoor heat exchanger is greater than or equal to a second set point, wherein the second set point is greater than 0 ℃.

12. The defrost control method according to claim 9, wherein before determining that the operation time period of the air conditioning system in the heating mode reaches a preset time period, the method further comprises:

Determining to enter the heating mode;

acquiring a first lowest initial temperature of the first outdoor heat exchanger in the initial operation time period;

after determining that the first current temperature of the second outdoor heat exchanger meets the first preset condition and before controlling the air conditioning system to switch to the uninterrupted defrost mode, the method further comprises:

acquiring a second current temperature of the first outdoor heat exchanger;

recording a third difference between the first lowest initial temperature and a second current temperature of the first outdoor heat exchanger;

the judging whether the first current temperature of the first outdoor heat exchanger meets a third preset condition or not specifically comprises:

and judging whether a fourth difference value between the first lowest initial temperature and the first current temperature of the first outdoor heat exchanger is larger than or equal to the sum of the third difference value and a third set value, wherein the third set value is larger than 0 ℃.

13. The defrost control method of claim 6, wherein the air conditioning system further comprises a signal valve for turning on or off the second circulation loop, the controlling the second four-way valve to switch the second circulation loop from a heating operation to a cooling operation, comprising:

Controlling the signal valve to cut off the second circulation loop;

controlling the second four-way valve to be powered down;

the rotating speeds of the indoor fan and the outdoor fan are reduced;

and controlling the signal valve to conduct the second circulation loop.

14. The defrost control method of claim 13, wherein after entering a no-stop defrost mode, the method further comprises:

acquiring a third current temperature of the second outdoor heat exchanger;

determining that a third current temperature of the second outdoor heat exchanger reaches a first target temperature;

and controlling the air conditioning system to switch to the heating mode.

15. The defrosting control method of claim 14, wherein the controlling the air conditioning system to switch to a heating mode comprises:

controlling the signal valve to cut off the second circulation loop;

the rotating speeds of the indoor fan and the outdoor fan are increased to the rotating speed required by heating;

controlling the signal valve to conduct the second circulation loop;

and controlling the second four-way valve to be electrified.