WO2022110771A1

WO2022110771A1 - Air conditioner

Info

Publication number: WO2022110771A1
Application number: PCT/CN2021/100428
Authority: WO
Inventors: 张恒; 孟建军; 董辰; 夏兴祥
Original assignee: 青岛海信日立空调系统有限公司
Priority date: 2020-11-30
Filing date: 2021-06-16
Publication date: 2022-06-02
Also published as: CN112444001A

Abstract

The present disclosure discloses an air conditioner, comprising at least one indoor unit and multiple outdoor unit modules. Each of the outdoor unit modules comprises: a compressor; a defrost throttling device; a vapor-side valve in parallel with the defrost throttling device; two outdoor heat exchangers arranged in parallel; two defrost switching devices respectively corresponding to the outdoor heat exchangers, and used to switch between the outdoor heat exchangers so as to enable communication with the defrost throttling device or a vapor-liquid separator; two liquid pipe throttling devices; a throttling device, one end of the throttling device being connected to the position at which one of the liquid pipe throttling devices is connected to a liquid side of a corresponding outdoor heat exchanger, and the other end of the throttling device being connected to the position at which the other liquid pipe throttling device is connected to a corresponding outdoor heat exchanger; and a control device. The control devices are used to control respective outdoor heat exchangers awaiting defrosting to undergo defrosting in turn, or to control a group of outdoor heat exchangers awaiting defrosting in each of the multiple outdoor unit modules, such the respective groups of outdoor heat exchangers undergo defrosting as a group in turn.

Description

Air conditioner

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese patent application with the application number 202011371832.6 and the invention name "air conditioner" filed with the China Patent Office on November 30, 2020, the entire contents of which are incorporated into this application by reference.

technical field

The present disclosure relates to the technical field of air conditioners, and in particular, to an air conditioner.

Background technique

The air source heat pump has a big problem in the heating operation: when the outdoor temperature and humidity reach a certain condition, frost will form on the air side of the outdoor heat exchanger, and as the amount of frost increases, the surface of the evaporator will gradually be blocked , resulting in the reduction of the heat transfer coefficient on the surface of the outdoor heat exchanger and the increase in the gas flow resistance, which seriously affects the heating effect of the machine. Therefore, the unit needs to be defrosted regularly.

SUMMARY OF THE INVENTION

Some embodiments of the present disclosure relate to an air conditioner, including:

at least one indoor unit;

Multiple outdoor unit modules, each outdoor unit module includes:

compressor;

a flow path switching device for switching the flow path of the refrigerant discharged from the compressor;

A defrost throttling device for throttling a portion of the refrigerant from the compressor;

an air-side valve, which is connected in parallel with the defrosting throttling device;

Two outdoor heat exchangers arranged in parallel;

Two defrosting switching devices, each of which corresponds to an outdoor heat exchanger, is used to switch the outdoor heat exchanger to communicate with the defrosting throttling device or communicate with the gas-liquid separator;

two liquid pipe throttling devices, each of which is connected to the indoor unit and each outdoor heat exchanger;

A throttling device, one end of which is connected to a position where a liquid pipe throttling device is connected to the liquid side of the outdoor heat exchanger, and the other end is connected to another liquid pipe throttling device that is connected to a position corresponding to the outdoor heat exchanger;

a control device, which controls the flow path switching device, each defrosting throttling device, the gas-side valve, each defrosting switching device, each liquid pipe throttling device and the throttling device in each outdoor unit module;

When a plurality of outdoor heat exchangers need to be defrosted, the control device controls the outdoor heat exchangers to be defrosted to be defrosted in turn, or one outdoor heat exchanger to be defrosted in each outdoor unit module of the plurality of outdoor unit modules. The combination of heat exchangers is used for rotating defrosting, so that the outdoor heat exchanger to be defrosted is performed as a defrosting heat exchanger, and the remaining outdoor heat exchangers are performed as an evaporator;

During rotation defrosting, the control device controls the flow path switching device in the outdoor unit module where each defrosting heat exchanger is located to power on; turn on the defrosting throttling device; The refrigerant flowing out of the defrosting throttling device is communicated with the main gas pipe of the defrosting heat exchanger; the liquid pipe throttling device and the gas side valve communicated with the defrosting heat exchanger are controlled to be closed; the throttling device is opened .

Description of drawings

In order to explain the technical solutions in the embodiments of the present disclosure more clearly, the following briefly introduces the accompanying drawings that need to be used in the embodiments. Obviously, the accompanying drawings in the following description are some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description serve to explain the principles of the disclosure.

FIG. 1 is a system structure diagram of an air conditioner according to some embodiments of the present disclosure;

2 is a flowchart of defrosting performed by a defrosting heat exchanger in an outdoor unit module according to some embodiments of the present disclosure;

FIG. 3 is another system structure diagram of the air conditioner according to some embodiments of the present disclosure.

Detailed ways

The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, but not all of the embodiments.

Throughout the specification and claims, the term "comprise" and other forms such as the third person singular "comprises" and the present participle "comprising" are to be construed unless the context otherwise requires The meaning of open and inclusive means "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" example)" or "some examples" and the like are intended to indicate that a particular feature, structure, material or characteristic related to the embodiment or example is included in at least one embodiment or example of the present disclosure. The schematic representations of the above terms are not necessarily referring to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be included in any suitable manner in any one or more embodiments or examples.

In describing some embodiments, the expression "connected" and its derivatives may be used. For example, the term "connected" may be used in describing some embodiments to indicate that two or more components are in direct physical or electrical contact with each other. However, the term "connected" may also mean that two or more components are not in direct contact with each other, but yet still co-operate or interact with each other. The embodiments disclosed herein are not necessarily limited by the content herein.

The use of "configured to" herein means open and inclusive language that does not exclude devices that are configured to perform additional tasks or steps.

In some embodiments of the present disclosure, a refrigeration cycle system of an air conditioner includes a compressor, a condenser, an expansion valve, and an evaporator. The refrigeration cycle process includes compression, condensation, expansion, and evaporation, and the supply of refrigerant to air that has been conditioned and heat-exchanged.

The compressor compresses the refrigerant gas in a high temperature and high pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process. The expansion valve expands the high-temperature and high-pressure liquid-phase refrigerant condensed in the condenser into a low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve and returns the refrigerant gas in a low temperature and low pressure state to the compressor. The evaporator can achieve the cooling effect by utilizing the latent heat of evaporation of the refrigerant to exchange heat with the material to be cooled. The temperature of the indoor space can be regulated by the entire refrigeration cycle air conditioner.

The air conditioner outdoor unit includes part of the compressor of the refrigeration cycle and the outdoor heat exchanger, the air conditioner indoor unit includes the indoor heat exchanger, and the expansion valve may be provided in the air conditioner indoor unit or the outdoor unit.

Indoor heat exchangers and outdoor heat exchangers can be used as condensers or evaporators. When the indoor heat exchanger is used as a condenser, the air conditioner is used as a heater in a heating mode; when the indoor heat exchanger is used as an evaporator, the air conditioner is used as a cooler in a cooling mode.

In some embodiments of the present disclosure, the outdoor unit module is similar to the air conditioner outdoor unit as described above.

The air conditioners involved in some embodiments of the present disclosure are multi-line air conditioners.

The air conditioner includes at least one indoor unit arranged side by side.

Each of the indoor units respectively includes indoor heat exchangers 11-1 and 11-2 (ie, the indoor heat exchangers as described above) and an indoor fan (not shown) for connecting the indoor heat exchangers 11-1 and 11-2, respectively. The cold or hot air produced in 11-2 is blown to the indoor space.

Of course, the number of indoor units is not limited to the above-mentioned number, and the number of indoor heat exchangers and indoor fans in each indoor unit is not limited to the above-mentioned number.

The air conditioner includes at least two outdoor unit modules, and the outdoor unit modules are arranged side by side.

The air conditioner includes two outdoor unit modules as an example for description. Referring to Figure 1, two outdoor unit modules W1 and W2 are shown in parallel.

The outdoor unit modules W1/W2 respectively include a compressor, a flow path switching device, a defrosting and throttling device, an air-side valve, two outdoor heat exchangers arranged in parallel, and two dehydrators corresponding to the two outdoor heat exchangers. Frost switching device, two liquid pipe throttling devices, two outdoor fans, one throttling device, and gas-liquid separator.

The structures of the outdoor unit module W1 and the outdoor unit module W2 are the same. And each outdoor unit module W1/W2 includes two parallel outdoor heat exchangers.

The configuration of the outdoor unit module W1 will be described as an example.

The outdoor unit module W1 includes a compressor 1, a flow path switching device 3, a defrosting and throttling device 19, a gas-side valve 18, and two outdoor heat exchangers 4-1 and 4-2 arranged in parallel, corresponding to the outdoor heat exchangers respectively. Two defrost switching devices 21 and 20 of 4-1 and 4-2, two liquid pipe throttle devices 6-1 and 6-2, two outdoor fans 5-1 and 5-2, one throttle device 28 And the gas-liquid separator 14.

The flow switching device 3 switches the flow of the refrigerant discharged from the compressor 1 to the indoor unit or the outdoor heat exchanger. In some embodiments of the present disclosure, the flow path switching device 3 is a four-way valve, which has four terminals C, D, S and E.

Referring to FIG. 1, for a two-pipe multi-line air conditioner, when the flow switching device 3 is powered off, C and D are connected by default, and S and E are connected, so that the indoor heat exchangers 11-1 and 11-2 are used as evaporators , while the outdoor heat exchangers 4-1 and 4-2 are used as condensers and air conditioners for refrigeration.

When the four-way valve is switched on, C and S are connected, and D and E are connected, so that the indoor heat exchangers 11-1 and 11-2 are used as condensers, and the outdoor heat exchangers 4-1 and 4-2 are used for Evaporator, air conditioner heating.

Referring to FIG. 1 , the number of outdoor heat exchangers and the number of outdoor fans are the same and correspond one-to-one.

In the outdoor unit module W1, the defrosting switching device 21/20 adopts a four-way valve, which has four terminals C, D, S and E. By default, when the power is off, C and D are connected and S and E are connected. When C and S are connected and D and E are connected.

Referring to FIG. 1, the refrigerant discharged from the compressor 1 flows out through the check valve 2, and the refrigerant after being switched by the flow path switching device 3 will first pass through the defrosting and throttling device 19 and/or with the defrosting and throttling device. 19 parallel air side valve 18, and then into the outdoor side.

The refrigerant throttled by the defrosting throttling device 19 is selected to enter the outdoor heat exchanger 4-1 or 4-2 through the state of the defrosting switching device 21/20 corresponding to the outdoor heat exchanger 4-1/4-2, That is, it alternately flows into the outdoor heat exchangers 4-1 and 4-2.

Part of the refrigerant discharged from the compressor 1 can be throttled to a suitable pressure through the defrosting throttling device 19, and then enters the outdoor heat exchanger 4-1 through the defrosting switching device 21 for heat exchange and defrosting.

Part of the refrigerant discharged from the compressor 1 can be throttled to a suitable pressure through the defrosting throttling device 19, and then enters the outdoor heat exchanger 4-2 through the defrosting switching device 20 for heat exchange and defrosting.

The control device is used to control the flow path switching device 3, the defrosting throttle device 19, the gas-side valve 18, the defrosting switching devices 21 and 20, the liquid pipe throttle devices 6-1 and 6-2 in the outdoor unit module W1, and the throttling device 28, so that at most one outdoor heat exchanger in the outdoor unit module W1 can be defrosted at the same time.

In some embodiments of the present disclosure, the structures of the outdoor unit module W2 and the outdoor unit module W1 are the same, and the control device is also used to control the flow path switching device, the defrosting and throttling device 19 ′, the gas side in the outdoor unit module W2 The valve, the defrosting switching device, the liquid pipe throttling device, and the throttling device 28' make it possible that at most one outdoor heat exchanger in the outdoor unit module W2 can be defrosted at the same time.

In some embodiments of the present disclosure, the gas-side valve 18 is a controllable valve such as a solenoid valve, a large-diameter two-way valve (eg, a reversible two-way valve with minimal resistance), and does not have a throttling function.

In some embodiments of the present disclosure, the defrosting throttling device 19 , the liquid pipe throttling device 6-1/6-2, and the throttling device 28 can all use electronic expansion valves, bidirectional thermal expansion valves, and the like.

In some embodiments of the present disclosure, if there are two outdoor unit modules W1 and W2 as shown in FIG. 1 , defrosting the defrosting heat exchanger may include the following three situations.

(1) One of the outdoor heat exchangers 4-1 and 4-2 in the outdoor unit module W1 serves as a defrosting heat exchanger, and the other one of the outdoor heat exchangers 4-1 and 4-2 in the outdoor unit module W1 is outdoor The heat exchanger and the outdoor heat exchangers 4-1' and 4-2' in the outdoor unit module W2 serve as evaporators;

After any one of the outdoor heat exchangers 4-1 and 4-2 in the outdoor unit module W1 is used as a defrosting heat exchanger for defrosting, any outdoor heat exchanger that has not been defrosted is selected for defrosting, and the remaining outdoor heat exchangers are used for defrosting. as an evaporator;

Until all outdoor heat exchangers are defrosted;

This situation is the sequential defrosting of the outdoor heat exchangers to be defrosted.

(2) One of the outdoor heat exchangers 4-1' and 4-2' in the outdoor unit module W2 serves as a defrosting heat exchanger, while the outdoor heat exchangers 4-1' and 4-2' in the outdoor unit module W2 Another outdoor heat exchanger in 4-2' and outdoor heat exchangers 4-1 and 4-2 in the outdoor unit module W1 are used as evaporators;

After one of the outdoor heat exchangers 4-1' and 4-2' in the outdoor unit module W1 is used as a defrosting heat exchanger for defrosting, any outdoor heat exchanger that has not been defrosted is selected for defrosting, and the remaining Outdoor heat exchanger as evaporator;

Until all outdoor heat exchangers are defrosted;

This situation is also the sequential defrosting of the outdoor heat exchanger to be defrosted;

(3) Select to perform combined defrosting on the outdoor heat exchanger 4-1 on the left side of the outdoor unit module W1 and the outdoor heat exchanger 4-1' on the left side of the outdoor unit module W2 at the same time, while the right side of the outdoor unit module W1 is defrosted. The outdoor heat exchanger 4-2 on the side and the outdoor heat exchanger 4-2' on the right side in the outdoor unit module W2 are used as evaporators;

After the combined defrosting of the outdoor heat exchanger 4-1 and the outdoor heat exchanger 4-1' is completed, select the outdoor heat exchanger 4-2 and the outdoor heat exchanger 4-2' for combined defrosting. 4-1 and outdoor heat exchanger 4-1' as evaporator;

Until all outdoor heat exchangers are defrosted;

This situation is also the combined rotation defrosting of the outdoor heat exchanger to be defrosted;

That is, at the same time, it is ensured that at most one outdoor heat exchanger in each outdoor heat exchanger W1 and W2 is defrosted, and two outdoor heat exchangers belonging to the same outdoor unit module cannot be defrosted at the same time, in other words, belong to the same outdoor One outdoor heat exchanger of the engine module is a defrosting heat exchanger, and the other is used as an evaporator to perform the heating process.

Combined rotation defrosting is used to improve the defrosting efficiency while ensuring the continuous heating of the room.

As for whether the air conditioner chooses to rotate the defrost sequentially or to combine the rotation defrost, it needs to be set in advance at the beginning of the operation of the air conditioner.

Referring to Figure 3, for the three-pipe heat recovery multi-line air conditioner, it is divided into the main cooling mode (that is, the indoor unit has two states of cooling and heating, and the cooling load is greater than the heating load, at this time, the outdoor heat exchanger is used for condensation. (i.e., the indoor unit has two states of cooling and heating, and the heating load is greater than the cooling load, and the outdoor heat exchanger is used as an evaporator).

Whether it is a two-pipe multi-line or three-pipe heat recovery multi-line (the working process will be described in detail below), when the outdoor heat exchanger 4-1 or 4-2 in the outdoor unit module W1 and the outdoor heat exchanger in the outdoor unit module W2 are The heat exchangers 4-1' or 4-2', or the outdoor heat exchangers 4-1 and 4-1' on the left side of the outdoor unit modules W1 and W2, and the outdoor unit modules W1 and W2 exchange heat with the outdoor unit on the right side The devices 4-2 and 4-2' are defrosted, and there is no difference in the control of each device in the outdoor unit modules W1 and W2.

[Operation mode of air conditioner]

Referring to FIG. 1 , the air conditioner has a normal heating operation mode, a normal cooling operation mode, a reverse defrost operation mode, and an alternate defrost operation mode.

Normal heating operation mode

The normal heating operation mode is no different from the normal heating operation mode of the air conditioner.

In the normal heating operation of the outdoor unit modules W1 and W2, the control methods of the components and the flow direction of the refrigerant are the same. Therefore, for the sake of simplicity, only the normal heating operation of the air conditioner including the outdoor unit module W1 and at least one indoor unit is described. model.

Referring to FIG. 1 , in some embodiments, when the air conditioner is in the normal heating operation mode, the defrost throttling device 19 in the outdoor unit module W1 can be at any opening degree, and in some embodiments, the defrost throttling device is selected to be closed device 19, the gas-side valve 18 can be closed or opened; in some embodiments, the defrost throttling device 19 is selected to be opened, the defrost switching devices 21 and 20 are powered on, and the liquid pipe throttling devices 6-1 and 6-2 are both powered on. On, both outdoor fans 5-1 and 5-2 are turned on. The throttling device 28 may be opened at any degree, and may be selectively closed in some embodiments.

When the defrosting switching devices 21 and 20 are powered on, D and E are connected and C and S are connected.

In some embodiments, the flow switching device 3 is powered on and reversed, so that D and E are connected and C and S are connected. The compressor 1 compresses the low-temperature and low-pressure refrigerant into a high-temperature and high-pressure state. D and E of the device 3 enter the refrigerant discharged from the compressor 1 into the indoor heat exchangers 11-1 and 11-2 through the gas-side shut-off valve 13 and the first extension pipe 12.

The indoor heat exchangers 11-1 and 11-2 condense and release heat after the internal heat exchange, and become liquid refrigerant, and then the refrigerant passes through the indoor unit side throttling devices 10-1 and 10-2, the second extension pipe 9 and the liquid side stop valve 8. Enter the liquid pipe throttling devices 6-1 and 6-2 to throttle to low temperature and low pressure gas-liquid two states, and the two-phase refrigerant enters the outdoor heat exchangers 4-1 and 4-2 to evaporate and absorb heat and become gaseous.

The refrigerant from the outdoor heat exchangers 4-1 and 4-2 enters the gas-liquid separator 14 through C and S of the defrosting switching devices 21 and 20, and is finally compressed by the suction compressor 1 to complete the heating cycle.

The outdoor fans 5-1 and 5-2 are always on throughout the normal heating operation mode.

Normal cooling operation mode

The normal cooling operation mode is no different from the normal cooling operation mode of the air conditioner.

When the outdoor unit modules W1 and W2 are in normal cooling operation, the device control methods and refrigerant flow directions are the same. Therefore, for the sake of simplicity, only the normal cooling operation mode of the air conditioner including the outdoor unit module W1 and at least one indoor unit is described.

Referring to FIG. 1 , in some embodiments, when the air conditioner is in the normal cooling operation mode, the defrost and throttle device 19 in the outdoor unit module W1 is at any opening degree, and in some embodiments, the defrost and throttle device 19 is selected to be opened , the gas side valve 18 is opened, the defrosting switching devices 21 and 20 are both powered off, the liquid pipe throttling devices 6-1 and 6-2 are both opened, the outdoor fans 5-1 and 5-2 are both opened, and the throttling device 28 is in Any degree of opening, and in some embodiments may be selected to be closed.

When the defrosting switching devices 21 and 20 are powered off, D and C are connected and E and S are connected.

The flow switching device 3 is powered off, and D and C are connected by default and E and S are connected. 19 and the gas-side valve 18 are connected in parallel, so as long as the gas-side valve 18 is open, regardless of whether the defrosting throttle device 19 is open, the refrigerant will all flow through the gas-side valve 18) and then enter the defrost switching devices 21 and 20 D and 20 C and enter the outdoor heat exchangers 4-1 and 4-2.

The outdoor heat exchangers 4-1 and 4-2 condense and release heat after heat exchange, and become liquid refrigerant, and then the refrigerant enters the indoor side through the liquid pipe throttling devices 6-1 and 6-2.

After the refrigerant entering the indoor side is throttled by the throttling devices 10-1 and 10-2, it enters the indoor heat exchangers 11-1 and 11-2 to evaporate and absorb heat and become gaseous. The indoor heat exchangers 11-1 and 11 The refrigerant from -2 enters the gas-liquid separator 14 through the first extension pipe 12, the gas-side shut-off valve 13 and the E and S of the flow switching device 3, and is finally sucked into the compressor 1 for compression to complete the refrigeration cycle.

Similarly, the refrigerant flow direction of the outdoor unit module W2 in the normal cooling operation mode is the same as that in the outdoor unit module W1.

In the normal cooling operation mode of the air conditioner having the outdoor unit modules W1 and W2, the refrigerant flows in the direction indicated by the dotted arrow in FIG. 1 .

The outdoor fans 5-1 and 5-2 are always on throughout the normal cooling operation mode.

Reverse defrost operation mode

When the control device of the air conditioner detects and determines that the outdoor heat exchangers 4-1 and/or 4-2 and/or 4-1' and/or 4-2' need to be defrosted, the compressor 1 first reduces the frequency or stops directly, and the indoor The fans and outdoor fans 5-1 and 5-2 in the outdoor unit module W1 and the outdoor fans in the outdoor unit module W2 all stop running.

After that, the air conditioner operates in the normal cooling operation mode, using all the outdoor heat exchangers 4-1, 4-2, 4-1' and 4-2' as condensers, and starts defrosting, that is, stops all indoor units. Defrost all outdoor heat exchangers for heating.

After defrosting is completed, the air conditioner re-enters the normal heating operation mode.

Alternating defrost operating modes

The rotation defrosting operation mode is operated under the condition that the outdoor heat exchanger needs to be defrosted, and the indoor unit is still expected to have a certain heating capacity, so that the outdoor heat exchanger to be defrosted (that is, the defrosting change While defrosting the heater), the air conditioner can maintain uninterrupted heating, reduce indoor temperature fluctuations, and enhance the heating comfort of users.

During the defrosting process, by controlling the defrosting pressure of the defrosting heat exchanger, the latent heat of the refrigerant is used for defrosting. It is short, and the heat obtained by the indoor unit is large, and the user comfort is high.

When there are multiple outdoor heat exchangers in the outdoor unit modules W1 and W2 to perform defrosting, the multiple outdoor heat exchangers to be defrosted perform sequential rotation defrosting or combined rotation defrosting.

When the outdoor heat exchangers 4-1, 4-2, 4-1' and 4-2' are defrosted in turn, enter the defrosting according to the defrosting conditions. , the control device performs control of the defrosting heat exchanger (ie, the outdoor heat exchanger that is defrosting) and the remaining outdoor heat exchangers.

When the outdoor heat exchangers 4-1, 4-2, 4-1' and 4-2' are defrosted by combination and rotation, enter the defrosting according to the defrosting conditions. During the process, the control device controls the defrosting heat exchanger and the remaining outdoor heat exchangers.

The defrosting condition can be judged according to the existing judgment basis, for example, according to the operating time of the compressor and the temperature difference between the ambient temperature and the outdoor unit coil temperature as the criterion.

In the above two defrosting processes, if there is a defrosting heat exchanger in the outdoor unit module, the control of the devices involving the defrosting heat exchanger in the outdoor unit module where the defrosting heat exchanger is located is the same. The remaining devices in the outdoor unit module remain the same as in the normal heating operation mode.

In some embodiments, if there is a defrosting heat exchanger in the outdoor unit module, during the defrosting process, the defrosting heat exchanger 4-1 (4-1') in the outdoor unit module W1 (W2) is located The control process of the opening degree of the defrosting throttle device 19 (19') and the opening degree of the throttle device 28 (28') is the same.

That is, defrosting of the outdoor heat exchanger 4-1 in the outdoor unit module W1 includes two cases.

The first case: the remaining outdoor heat exchangers 4-2 and the outdoor heat exchangers 4-1' and 4-2' in the outdoor unit module W2 are used as evaporators.

The second case: the outdoor heat exchanger 4-1 in the outdoor unit module W1 and the outdoor heat exchanger 4-1' in the outdoor unit module W2 are combined to defrost at the same time, and the other outdoor heat exchangers 4-2 and the outdoor unit module W2 The outdoor heat exchanger 4-2' acts as an evaporator.

The control process of the opening degree of the defrosting and throttling device 19 and the opening degree of the throttling device 28 in the outdoor heat exchanger W1 and the opening degree of the defrosting and throttling device 19 ′ and the opening of the throttling device 28 ′ in the outdoor heat exchanger W2 The degree control process is the same.

In some embodiments, referring to FIG. 1 , only the defrosting of the outdoor heat exchanger 4-1 in the outdoor unit module W1 is described as an example. The defrosting process of the defrosting heat exchanger 4-1 is described below.

S1: Control the flow path switching device 3 in the outdoor unit module where the defrosting heat exchanger is located to be powered on, control the defrosting throttle device 19, the gas side valve 18, and the defrosting switching device 21/20, so that the compressor 1 discharges Part of the refrigerant enters the defrost heat exchanger through the defrost throttling device 19 and the defrost switching device 21/20, closes the liquid pipe throttling device connected to the defrost heat exchanger, controls the opening of the throttling device, and the remaining outdoor exchange. The heater performs as an evaporator.

The outdoor heat exchanger 4-1 in the outdoor unit module is used as the defrosting heat exchanger, and the defrosting process is entered.

Keep the flow switching device 3 in the power-on state, control the defrosting throttling device 19 to open and the gas-side valve 18 to close, the defrosting switching device 21 is powered off, the defrosting switching device 20 is powered on, the outdoor fan 5-1 is turned off, and the The liquid pipe throttle device 6-1 opens the throttle device 28, and the rest of the devices in the outdoor unit module W1 remain the same as in the normal heating operation mode.

The flow path switching device 3, the flow path adjusting device 19, the gas-side valve 18, the defrosting switching device 20/21, the outdoor fan 5-1, the liquid pipe throttle device 6-1 and the throttle device 28 are all described above. It is a device in the outdoor unit module W1.

In the first case, each device in the outdoor unit module W2 remains the same as it is in the normal heating operation mode.

In the second case, the outdoor heat exchanger 4-1 in the outdoor unit module W2 also executes S1 correspondingly, and each device in the outdoor heat exchanger 4-2' in the outdoor unit module W2 keeps its normal heating operation. The state in the schema is the same.

Referring to FIG. 1 again, the solid arrows indicate the refrigerant flow during the defrosting process of the outdoor heat exchanger 4-1 in the outdoor unit module W1, wherein the outdoor heat exchanger 4-2 in the outdoor unit module W1 and the outdoor heat exchanger 4-2 in the outdoor unit module W2 Both the outdoor heat exchangers 4-1' and 4-2' are implemented as evaporators.

When entering the rotation defrosting operation mode, the compressor 1 compresses the low-temperature and low-pressure refrigerant into a high-temperature and high-pressure state, and discharges the high-temperature and high-pressure refrigerant through the check valve 2 .

A part of the high-temperature and high-pressure refrigerant enters the indoor heat exchangers 11-1 and 11-2 through D and E of the flow switching device 3, the gas-side shut-off valve 13, and the first extension pipe 12.

After heat exchange in the indoor heat exchangers 11-1 and 11-2, the heat is condensed and released to become a liquid refrigerant, and then the refrigerant passes through the indoor unit side throttling devices 10-1 and 10-2, the second extension pipe 9 and the liquid side cutoff Valve 8, into the liquid pipe throttling device 6-2.

Another part of the high-temperature and high-pressure refrigerant is throttled to a suitable pressure through the defrosting throttling device 19, and then enters D and C of the defrosting switching device 21 and enters the outdoor heat exchanger 4-1 for heat exchange and defrosting.

The refrigerant heat-exchanged from the outdoor heat exchanger 4-1 is throttled by the throttling device 28 and then combined with the refrigerant from the liquid pipe throttling device 6-2, and then enters the outdoor heat exchanger 4-2 for evaporation and absorption The heat becomes gaseous, and the refrigerant from the outdoor heat exchanger 4-2 enters the gas-liquid separator 14 through C and S of the defrosting switching device 20.

Of course, the number of outdoor unit modules is not limited to two, and the air conditioner may also include more than two outdoor unit modules.

No matter how many outdoor unit modules there are, when multiple outdoor heat exchangers in the multiple outdoor unit modules are being defrosted sequentially or in combination, the two outdoor heat exchangers in each outdoor unit module are defrosted by rotation. frosted.

If there is a defrost heat exchanger in the outdoor unit module, the control of the components related to the defrost heat exchanger in the outdoor unit module where the defrost heat exchanger is located is the same.

For example, the outdoor heat exchanger 4-1 in the outdoor heat exchanger W1 is a defrosting heat exchanger, and the opening of the throttle device 28 is controlled and adjusted according to the outlet subcooling degree of the outdoor heat exchanger 4-1 and the target outlet subcooling degree range. The outlet subcooling degree of the outdoor heat exchanger 4-1 tends to be maintained within the target outlet subcooling degree range; according to the defrosting pressure and the target defrosting pressure range, the opening degree of the defrosting throttling device 19 is controlled and adjusted to make The defrosting pressure of compressor 1 tends to be maintained within the target defrosting pressure range, ensuring the outlet temperature and defrosting pressure of the heat exchanger, shortening the defrosting time, improving the defrosting speed and efficiency, and continuously heating and defrosting the air conditioner. It can ensure the maximum capacity of the indoor unit and improve the indoor thermal comfort of users.

When defrosting the outdoor heat exchanger 4-1, referring to FIG. 2, how to control the opening degree of the throttle device 28 and the opening degree of the defrosting throttle device 19 will be described in detail.

Before entering the defrosting process, it is necessary to set the initial opening degrees of the throttle device 28 and the defrost throttle device 19 during defrosting.

S1': Set the target outlet subcooling degree range of the outdoor heat exchanger 4-1, and set the target defrosting pressure range.

In some embodiments of the present disclosure, the target outlet subcooling degree Te1sco exists in a range, for example, 0°C≤Te1sco≤10°C.

According to the target outlet subcooling degree Te1sco, set the target outlet subcooling degree range (Te1sco-λ, Te1sco+λ], for example, 0°C<λ<3°C.

In some embodiments of the present disclosure, the target defrosting pressure Pfo is a function Pfo=f(Ta) of the ambient temperature Ta, and the function Pfo=f(Ta) may be a preset function determined during the debugging of the air conditioner.

When the ambient temperature sensor detects the ambient temperature Ta, the target defrosting pressure Pfo can be known according to the function f(Ta).

According to the target defrosting pressure Pfo, a target defrosting pressure range (Pfo-δ, Pfo+δ) is set, for example, 0MPa<δ<0.5MPa.

S2': Calculate the outlet subcooling degree Te1sco of the outdoor heat exchanger 4-1.

The outlet subcooling degree Te1sc of the outdoor heat exchanger 4-1 is calculated by the defrosting pressure Pf (detected by the pressure sensor 221) and the outlet temperature Te1 (detected by the temperature sensor 231) of the outdoor heat exchanger 4-1.

That is, Te1sc=Tec-Te1, where Tec is the corresponding saturation temperature under the defrosting pressure Pf, which can be obtained by querying the prior art.

S3': Compare whether the outlet subcooling degree Te1sc is within the target outlet subcooling degree range;

S31': If the outlet subcooling degree Te1sc is within the target outlet subcooling degree range, keep the opening degree of the throttle device 28 and go to S4'; if not, adjust the opening degree of the throttle device 28 and go to S4' .

The specific process of adjusting the opening degree of the throttle device 28 is described below.

S32': If the outlet subcooling degree Te1sc is greater than the upper limit value of the target outlet subcooling degree range, increase the opening degree of the throttle device 28 by one adjustment step, and execute to S4'.

That is, the next opening degree of the throttle device 28 EV28(n+1)=EV28(n)+ΔEV28, where ΔEV28 is the number of adjustment steps, and the number of adjustment steps can be selected as 0.1%-10% pls of the total opening degree ( the number of steps).

S33 ′: If the outlet subcooling degree Te1sc is less than the lower limit value of the target outlet subcooling degree range, reduce the opening of the throttle device 28 for one adjustment step, and execute to S4 ′.

That is, the next opening degree of the throttle device 28 EV28(n+1)=EV28(n)-ΔEV28, where ΔEV28 is the number of adjustment steps, and the number of adjustment steps can be selected as 0.1%-10% pls of the total opening degree ( the number of steps).

S4': Compare whether the defrosting pressure Pf is within the target defrosting pressure range, if so, keep the opening of the defrosting throttle device 19, and go to S2, if not, adjust the opening of the defrosting throttle device 19, and Execute to S2.

The process of specifically adjusting the opening degree of the defrosting throttle device 19 is described below.

S41 ′: If the defrosting pressure Pf is within the target defrosting pressure range, the opening degree of the defrosting throttle device 19 is maintained, and the process proceeds to S2 .

S42': If the defrosting pressure Pf is greater than the upper limit value of the target defrosting pressure range, reduce the opening of the defrosting throttle device 19 by one adjustment step, and then go to S2.

That is, the next opening degree of the defrosting throttle device 19 EV19(n+1)=EV19(n)-ΔEV19, where ΔEV19 is the number of adjustment steps, and the number of adjustment steps can be selected as 0.1%-10% of the total opening degree pls (ie steps).

S43 ′: If the defrosting pressure Pf is less than the lower limit value of the target defrosting pressure range, increase the opening of the defrosting throttle device 19 by one adjustment step, and then go to S2 .

That is, the next opening degree of the defrosting throttle device 19 is EV19(n+1)=EV19(n)+ΔEV19, where ΔEV19 is the number of adjustment steps, and the number of adjustment steps can be selected as 0.1%-10% of the total opening degree pls (ie steps).

S2: Determine whether the defrosting is completed, if so, exit the defrosting process, if not, return to S2', and adjust the opening of the throttle device 28 and the defrost throttle device 19 again.

As the defrosting end condition, it can be determined whether the defrosting duration t1 reaches the first preset time T1, or whether the outlet temperature Te1 of the outdoor heat exchanger 4-1 is greater than or equal to the first temperature preset value Tef (for example, 2°C<Tef< 20°C) and maintain for a certain period of time T; if one of the two conditions is met, it means that the defrosting is over, otherwise the judgment is continued.

Of course, the defrosting end condition is not limited to this. For example, whether the gas pipe temperature Tg of the outdoor heat exchanger 4-1 is greater than or equal to the set temperature Tn and whether the suction pressure Ps of the compressor 1 is greater than or equal to the set pressure Po can be used. or the adjustment times of the opening degrees of the throttle device 28 and the defrost throttle device 19 can be adjusted, and so on.

Although S3' is executed before S4' as described above, the sequence of S3' and S4' is not limited, that is, S4' can also be executed before S3'.

After the defrosting of the outdoor heat exchanger 4-1 is completed, the defrosting process is exited, and thereafter the normal heating operation process is entered.

The outdoor heat exchanger 4-1 exits the defrosting process and enters the normal heating operation process, which at least includes:

(1) Control the defrosting switching device 21 to be powered on, so that the gas side of the defrosting heat exchanger 4-1 is communicated with the gas-liquid separator 14;

(2) Turn on the outdoor fan 5-1;

(3) Open the liquid pipe throttling device 6-1;

During the defrosting process, the indoor side throttling devices 10-1 and 10-2 maintain the control before defrosting, and the throttling device 6-2 maintains the normal heating control, that is, controls the outlet of the outdoor heat exchanger 4-2 to overheat. The heat degree Ts2, that is, the temperature sensor 233 detects the main gas pipe temperature T, the pressure sensor 222 detects the main gas pipe pressure P, and the outlet superheat degree Ts2 of the outdoor heat exchanger 4-2 is the main gas pipe temperature T and the main gas pipe pressure P corresponding to the saturation temperature. Poor, the outlet superheat Ts2 is controlled within 0-2°C.

Similarly, when the outdoor heat exchanger 4-1 is out of defrosting and the outdoor heat exchanger 4-2 is defrosting, the throttling device 6-1 is also used to control the outlet superheat of the outdoor heat exchanger 4-1 at within 0-2°C.

After that, the outdoor heat exchanger 4-2 acts as a defrosting heat exchanger and enters the defrosting process, while the outdoor heat exchanger 4-1 acts as an evaporator and maintains the normal heating operation process.

Keep the flow switching device 3 powered on, keep open the defrosting throttle device 19 and close the gas side valve 18, control the power off and defrost switching device 20, open the throttle device 28, close the outdoor fan 5-2 and the liquid pipe The throttling device 6-2, and the rest of the devices remain the same as in the normal heating operation mode.

For the defrosting process of the outdoor heat exchanger 4-2, refer to the defrosting process of the outdoor heat exchanger 4-1.

When the outdoor heat exchanger 4-2 performs defrosting, the outdoor heat exchanger 4-1 performs a normal heating operation process.

Similarly, after the outdoor heat exchanger 4-2 exits from defrosting, an outdoor heat exchanger to be defrosted in the outdoor unit module W2 (for example, the outdoor heat exchanger 4-1' can be used as a defrosting heat exchanger. execution), at this time, the outdoor heat exchanger 4-2' in the outdoor unit module W2 performs a normal heating operation process.

The above content mainly describes the control of each device of the outdoor unit module where the defrosting heat exchanger is located when the defrosting is rotated in turn. Similarly, when the outdoor heat exchangers in the multiple outdoor unit modules W1 and W2 perform combined rotation defrosting, for each outdoor unit module, the defrosting heat exchangers in the outdoor unit module are as described above. Defrost is performed in the defrost control method described above.

And when all the defrosting heat exchangers that are defrosting at the same time meet the defrosting end condition, the defrosting can be ended and the normal heating operation mode can be entered.

Referring to Fig. 1, for example, when the outdoor heat exchanger 4-1 and the outdoor heat exchanger 4-1' are defrosted in combination, the outdoor heat exchanger 4-1 and the outdoor heat exchanger 4-1' enter the defrost at the same time, The outdoor heat exchanger 4-2 and the outdoor heat exchanger 4-2' serve as evaporators.

During the defrosting process, for the outdoor unit module W1, the outdoor heat exchanger 4-1 is defrosted by the above-mentioned defrosting process, and for the outdoor unit module W2, the above-mentioned defrosting process is also used to defrost the outdoor heat exchanger 4-1. For the defrosting of the heat exchanger 4-1', refer to the above for the specific process, which will not be repeated here.

After both the outdoor heat exchanger 4-1 and the outdoor heat exchanger 4-1' meet the defrosting end condition, they both exit the defrosting process and enter the normal heating operation mode.

In some embodiments, whether the defrosting duration t1 reaches the first preset time T1, or whether the outlet temperature Te1 of the outdoor heat exchanger 4-1 and the outlet temperature Te1' of the outdoor heat exchanger 4-1' are both greater than or equal to the th A temperature preset value Tef is maintained for a certain period of time T; if one of the two conditions is satisfied, it means that the defrosting is completed, otherwise the judgment is continued.

After that, the outdoor heat exchanger 4-2 and the outdoor heat exchanger 4-2' perform combined defrosting.

You can choose to perform a reverse defrost operation mode after rotating the outdoor heat exchangers 4-1, 4-2, 4-1' and 4-2' for many times, so that the outdoor heat exchangers 4-1, 4-1' and 4-2' 4-2, 4-1' and 4-2' for a thorough defrost. Of course, the reverse defrost operation mode can also be selected under other conditions.

[Three-pipe heat recovery function]

The air conditioners of some embodiments of the present disclosure can also be compatible with the three-pipe heat recovery function. Referring to FIG. 3 , it shows a system structure diagram of an air conditioner that takes into account two pipes and three pipes.

1 and 3, the air conditioner further includes a plurality of first switching valves a and a plurality of second switching valves b connected in parallel, the first switching valves a, the second switching valves b and one indoor heat exchanger correspond to each other .

The first switching valve a is used to branch at least part of the refrigerant from the compressor 1 switched by the flow switching devices in the respective outdoor unit modules W1 and W2, and flow into the indoor heat exchangers 11-1/11-2 accordingly.

One end of the second switching valve b is connected to the position where the first switching valve a is connected to the gas side of the indoor heat exchangers 11-1/11-2, and the other end is connected to the gas-liquid separator (for example, the gas-liquid separator in each outdoor unit module W1 and W2) The gas-liquid separator 14) is connected, specifically, referring to FIG. 1 , the other end is communicated with the gas-liquid separator 14 through the extension pipe 26 and the gas-side shut-off valve 27 .

Two pipes and three pipes are realized by switching the first switching valve a and the second switching valve b.

Referring to FIG. 3 , in addition to the above-mentioned operation modes, the air conditioner also has a main cooling operation mode, a main heating operation mode, and a heating defrost mode in the main heating operation mode.

In the main cooling operation mode and the main heating operation mode, the control of each device in the outdoor unit module W1 and the outdoor unit module W2 and the flow direction of the refrigerant are exactly the same.

Therefore, for the sake of simplicity, the three-control function of the air conditioner will be described by taking an air conditioner structure composed of the outdoor unit module W1 and at least one indoor unit as an example.

The main cooling operation mode, that is, the indoor unit has two states of cooling and heating, and the cooling load is greater than the heating load, and the outdoor heat exchanger is used as a condenser at this time.

In the main cooling operation mode, it is assumed that the indoor heat exchanger 11-1 is used as an evaporator (ie, the indoor heat exchanger 11-1 is cooling) and the indoor heat exchanger 11-2 is used as a condenser (ie, the indoor heat exchanger 11-2 heating).

Referring to FIG. 3 , the flow path switching device 3 in the outdoor unit module W1 is powered on, the defrosting throttle device 19 is at any opening degree, the gas side valve 18 is opened, the defrosting switching devices 21 and 20 are both powered off, and the liquid pipe is throttled The devices 6-1 and 6-2 are both turned on, the outdoor fans 5-1 and 5-2 are both turned on, the throttling device 28 is at any opening degree, and controls the first switching valve a connected to the indoor heat exchanger 11-1 (ie The first switching valve 24a) is closed and the second switching valve b (ie, the second switching valve 24b) is opened, and the first switching valve a (ie, the first switching valve 25a) connected to the indoor heat exchanger 11-2 is controlled to be opened and the first switching valve 25a connected to the indoor heat exchanger 11-2 is controlled. The second switching valve b (ie, the second switching valve 25b) is closed.

The flow switching device 3 is powered on, D and E are connected and C and S are connected, the compressor 1 compresses the low-temperature and low-pressure refrigerant into a high-temperature and high-pressure state, and then divides it into two parts after passing through the check valve 2 .

A part of the high-temperature and high-pressure refrigerant enters D and C of the defrosting switching devices 21 and 20 through the gas-side valve 18 and enters the outdoor heat exchangers 4-1 and 4-2. After the heat exchange in the outdoor heat exchangers 4-1 and 4-2, the heat is condensed and released to become a liquid refrigerant, and then the refrigerant flows through the liquid pipe throttling devices 6-1 and 6-2 to the liquid side stop valve 8 and the second extension pipe 9 .

Another part of the high-temperature and high-pressure refrigerant passes through D and E of the flow switching device 3, passes through the gas-side stop valve 13, the first extension pipe 12, and the first switching valve 25a, enters the indoor heat exchanger 11-2, and then condenses and releases heat after heat exchange. , it becomes a liquid refrigerant, and then the refrigerant passes through the indoor unit side throttling device 10-2, and joins with the refrigerant from the outdoor side that passes through the liquid side stop valve 8 and the second extension pipe 9 and enters the indoor unit side throttling device 10-1 for throttling Depressurization is gas-liquid two states.

Then, it enters the indoor heat exchanger 11-1 to evaporate and absorb heat, and becomes a gaseous state. It enters the gas-liquid separator 14 through the second switching valve 24b, the extension pipe 26, and the gas-side shut-off valve 27, and is finally compressed by the suction compressor 1. Main refrigeration cycle.

In the main heating mode, that is, the indoor unit has two states of cooling and heating, and the heating load is greater than the cooling load, and the outdoor heat exchanger is used as an evaporator at this time.

In the main heating mode, it is assumed that the indoor heat exchanger 11-1 functions as a condenser (ie, the indoor heat exchanger 11-1 heats) and the indoor heat exchanger 11-2 functions as an evaporator (ie, the indoor heat exchange 11-2 refrigeration).

Referring to FIG. 3 , the flow path switching device 3 in the outdoor unit module is powered on, the defrosting throttling device 19 is at any opening degree, the gas side valve 18 can be selectively opened or closed, and in some embodiments, it is selected to be closed, and the defrosting switching device Both 21 and 20 are powered on, the liquid pipe throttling devices 6-1 and 6-2 are both turned on, the outdoor fans 5-1 and 5-2 are both turned on, the throttling device 28 is at any opening degree, and the first switching valve 24a is controlled to open And the second switching valve 24b is closed, and the first switching valve 25a is controlled to be closed and the second switching valve 25b to be opened.

The flow switching device 3 is powered on, D and E are connected and C and S are connected, the compressor 1 compresses the low temperature and low pressure refrigerant into a high temperature and high pressure state, and passes through the check valve 2, D and E of the flow switching device 3, and the gas side The shut-off valve 13, the first extension pipe 12, and the first switching valve 24a enter the indoor heat exchanger 11-1 after heat exchange, condense and release heat, and become liquid refrigerant, and then the refrigerant flows out through the indoor unit side throttle device 10-1, and into two parts.

Part of it enters the liquid pipe throttling devices 6-1 and 6-2 through the second extension pipe 9 and the liquid side stop valve 8 to be throttled to the low temperature and low pressure gas-liquid two states, and then enters the outdoor heat exchangers 4-1 and 4-2. Evaporation absorbs heat and turns into a gaseous state, and the refrigerants from the outdoor heat exchangers 4-1 and 4-2 flow out through C and S of the defrosting switching devices 21 and 20.

The other part is throttled and depressurized by the throttling device 10-2 on the indoor unit side, and enters the indoor heat exchanger 11-2 to evaporate and absorb heat, and become gaseous. It is combined with the refrigerant flowing out of C and S through the defrosting switching devices 21 and 20 as described above, and then enters the gas-liquid separator 14, and is finally compressed by the suction compressor 1 to complete the main heating cycle.

The heating and defrosting operation mode in the main heating operation mode, that is, the indoor unit has two states of cooling and heating, and the heating load is greater than the cooling load, and multiple outdoor heat exchangers in the outdoor unit modules W1 and W2 Perform a sequential or combined rotation defrost.

In the heating and defrosting operation mode in the main heating operation mode, the plurality of outdoor heat exchangers in the outdoor unit modules W1 and W2 perform the process of sequentially rotating defrosting or combined rotating defrosting except for the plurality of first switching valves a, multiple Except for the control of the second switching valve b and the indoor side throttling devices 10-1 and 10-2, the rest of the devices remain the same as the two-pipe air conditioners described above in the state of sequential rotation defrosting or combined rotation defrosting.

In the heating and defrosting operation mode in the main heating mode, it is assumed that the indoor heat exchanger 11-1 is used as a condenser (ie, the indoor heat exchanger 11-1 is used for heating) and the indoor heat exchanger 11-2 is used as an evaporation (ie, the indoor heat exchanger 11-2 for cooling), and the outdoor heat exchanger 4-1 is a defrosting heat exchanger.

Referring to FIG. 3 , the flow path switching device 3 in the outdoor unit module is powered on, the defrosting throttling device 19 is opened, the gas side valve 18 is closed, the defrosting switching device 21 is powered off and the defrosting switching device 20 is powered on, and the liquid pipe joint The flow device 6-1 is closed and the liquid pipe throttle device 6-2 is opened, the outdoor fan 5-1 is closed and the outdoor fan 5-2 is opened, the throttle device 28 is opened, and the first switching valve 24a is controlled to open and the second switching valve 24b To close, the first switching valve 25a is controlled to be closed and the second switching valve 25b to be opened.

When the defrosting switching device 21 is powered off, D and C are connected and E and S are connected. When the defrosting switching device 20 is powered on, D and E are connected and C and S are connected.

The flow switching device 3 is powered on, D and E are connected and C and S are connected, the compressor 1 compresses the low-temperature and low-pressure refrigerant into a high-temperature and high-pressure state, and then divides it into two paths after passing through the check valve 2 .

All the way through the defrosting throttling device 19 to throttle to a suitable pressure, and then enter D and C of the defrosting switching device 21 and enter the outdoor heat exchanger 4-1 for heat exchange and defrosting.

The refrigerant heat-exchanged from the outdoor heat exchanger 4-1 is throttled by the throttle device 28 and then flows out.

The other path passes through D and E of the flow path switching device 3, the gas-side stop valve 13, the first extension pipe 12, and the first switching valve 24a, and enters the indoor heat exchanger 11-1 after heat exchange, condensing and releasing heat, and becomes a liquid refrigerant. Then the refrigerant flows out through the indoor unit side throttling device 10-1, and is divided into two parts.

A part of it enters the liquid pipe throttling device 6-2 through the second extension pipe 9 and the liquid side stop valve 8 to be throttled to the low temperature and low pressure gas-liquid two states, and then enters the outdoor heat exchanger 4-2 to evaporate and absorb heat and become gaseous. The refrigerant coming out of the outdoor heat exchanger 4-2 is combined with the refrigerant flowing out through the throttling device 28, and then flows out through C and S of the defrosting switching device 20 together.

The other part is throttled and depressurized by the throttling device 10-2 on the indoor unit side, and enters the indoor heat exchanger 11-2 to evaporate and absorb heat, and become gaseous. It is combined with the refrigerants flowing out of C and S through the defrosting switching device 20 as described above, and then enters the gas-liquid separator 14, and is finally sucked into the compressor 1 for compression to complete the heating and defrosting mode under the main heating cycle. When it comes to the three-pipe heat recovery function, see Fig. 3, when the defrosting is performed in rotation, the control of each device in the outdoor unit modules W1 and W2 is the same as the control of each device in the outdoor unit modules W1 and W2 in the two-pipe air conditioner of.

[wind field separation]

For each outdoor unit module, eg, the outdoor unit module W1, two outdoor fans 5-1 and 5-2 are provided, which correspond to the outdoor heat exchangers 4-1 and 4-2, respectively.

The outdoor fans 5-1 and 5-2 are independently controlled by the control device, and the outdoor heat exchanger 4-1 and the outdoor fan 5-1 form a first wind field, and the outdoor heat exchanger 4-2 and the outdoor fan 5- 2 to form a second wind field.

Since the outdoor fan 5-2 corresponding to the outdoor heat exchanger 4-2 keeps running when the outdoor heat exchanger 4-1 is defrosting, in order to prevent the wind field generated by the outdoor fan 5-2 from blowing through the outdoor heat exchange If the outdoor heat exchanger 4-1 cannot be effectively defrosted, in some embodiments of the present disclosure, a separation device 101 for separating the wind field is provided (for this part, please refer to the application number CN202010279447.2 , the patent document with the invention name "air conditioner outdoor unit").

The separating device 101 is used to separate the first wind farm and the second wind farm.

That is, when the outdoor fan 5-1 is operating and the outdoor fan 5-2 is not operating, it does not allow wind to flow through the outdoor heat exchanger 4-2, and when the outdoor fan 5-2 is operating and the outdoor fan 5-1 is not operating , which does not allow wind to flow through the outdoor heat exchanger 4-1.

In this way, when the outdoor heat exchanger 4-1 is defrosted, since the partition device 101 separates the first wind field and the second wind field, even if the outdoor fan 5-2 is still operating, the first wind field will not be generated. influences.

In this way, it is effectively avoided that the surface of the outdoor heat exchanger 4-1 is defrosted with wind blowing over it, thereby preventing the situation that the condensation load is too large to effectively defrost when the outdoor temperature is low, and the full temperature range can be realized. Uninterrupted heating.

In addition, when the outdoor fan 5-1 stops running (that is, the outdoor heat exchanger 4-1 is defrosting), the rotation speed of the outdoor fan 5-2 can be appropriately increased to further enhance the heating effect, reduce indoor temperature fluctuations, and greatly improve the Air conditioner heating capacity and user heating comfort.

And when the outdoor heat exchanger 4-1 exits the defrosting process and enters the normal heating operation process, the outdoor fan 5-1 of the outdoor heat exchanger 4-2 is correspondingly turned on and the outdoor fan 5-2 of the outdoor heat exchanger 4-2 is turned off.

In some embodiments of the present disclosure, the outdoor unit module W2 also has the separating device, which is used to separate the adjacent area formed between the outdoor fan in the outdoor unit module W2 and the corresponding outdoor heat exchanger 4-1'/4-2' Wind farm, improve the effectiveness of the rotation defrosting in the outdoor unit module W2, and improve the indoor thermal comfort.

The above embodiments are only used to illustrate the technical solutions of the present disclosure, but not to limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art can still The recorded technical solutions are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions claimed in the present disclosure.

Claims

An air conditioner, characterized in that it includes:

at least one indoor unit;

Multiple outdoor unit modules, each outdoor unit module includes:

compressor;

a flow path switching device for switching the flow path of the refrigerant discharged from the compressor;

A defrost throttling device for throttling a portion of the refrigerant from the compressor;

an air-side valve, which is connected in parallel with the defrosting throttling device;

Two outdoor heat exchangers arranged in parallel;

Two defrosting switching devices, each of which corresponds to an outdoor heat exchanger, is used to switch the outdoor heat exchanger to communicate with the defrosting throttling device or communicate with the gas-liquid separator;

two liquid pipe throttling devices, each of which is connected to the indoor unit and each outdoor heat exchanger;

A throttling device, one end of which is connected to a position where a liquid pipe throttling device is connected to the liquid side of the outdoor heat exchanger, and the other end is connected to another liquid pipe throttling device that is connected to a position corresponding to the outdoor heat exchanger;

a control device, which controls the flow path switching device, each defrosting throttling device, the gas-side valve, each defrosting switching device, each liquid pipe throttling device and the throttling device in each outdoor unit module;

When a plurality of outdoor heat exchangers need to be defrosted, the control device controls each outdoor heat exchanger to be defrosted to be defrosted in turn or a combination of outdoor heat exchangers to be defrosted in each of the plurality of outdoor unit modules Perform combined rotation defrosting, so that the outdoor heat exchanger to be defrosted is performed as a defrosting heat exchanger, and the remaining outdoor heat exchangers are performed as an evaporator;

During rotation defrosting, the control device controls the flow path switching device in the outdoor unit module where each defrosting heat exchanger is located to power on; controls the defrosting throttling device to open; controls the defrosting switching device to make the The refrigerant flowing out of the defrosting throttling device is communicated with the main gas pipe of the defrosting heat exchanger; the liquid pipe throttling device and the gas side valve communicated with the defrosting heat exchanger are controlled to be closed; flow device.
The air conditioner according to claim 1, wherein,

When defrosting the defrosting heat exchanger, the control device is configured to:

Control to open the throttling device in the outdoor unit module where the defrosting heat exchanger is located, and control and adjust the opening of the throttling device according to the outlet subcooling degree of the defrosting heat exchanger and the target outlet subcooling degree range. Spend;

The defrosting throttle device is controlled to open, and the opening degree of the defrosting throttle device is controlled and adjusted according to the defrosting pressure and the target defrosting pressure range.
The air conditioner according to claim 1, wherein,

Control the opening of the throttling device, and control and adjust the opening degree of the throttling device according to the outlet subcooling degree of the defrosting heat exchanger and the target outlet subcooling degree range, specifically:

Setting the target outlet subcooling range of the defrosting heat exchanger;

Calculate the outlet subcooling degree of the defrosting heat exchanger;

Compare whether the outlet subcooling degree is within the target outlet subcooling degree range, if yes, keep the current opening degree of the throttle device, if not, adjust the opening degree of the throttle device;

Control the opening of the defrosting throttling device, and control the opening of the defrosting throttling device according to the defrosting pressure and the target defrosting pressure range, specifically:

Set the target defrosting pressure range;

Calculate the defrosting pressure of the heat exchanger to be defrosted;

Compare whether the defrosting pressure is within the target defrosting pressure range, if yes, keep the opening degree of the defrosting throttle device, if not, adjust the opening degree of the defrosting throttle device.
The air conditioner according to claim 3, wherein,

Adjust the opening of the throttling device, specifically:

When the outlet subcooling degree is greater than the upper limit value of the target outlet subcooling degree range, increasing the opening degree of the throttling device;

When the outlet subcooling degree is less than the lower limit value of the target outlet subcooling degree range, reducing the opening degree of the throttling device;

Adjust the opening degree of the defrosting throttling device, specifically:

When the defrosting pressure is greater than the upper limit value of the target defrosting pressure range, reducing the opening of the defrosting throttle device;

When the defrost pressure is smaller than the lower limit value of the target defrost pressure range, the opening degree of the defrost throttle device is increased.
The air conditioner according to any one of claims 1 to 4, wherein the control device is configured to:

When the defrosting heat exchanger is defrosting, if the first preset defrosting time is reached, the defrosting heat exchanger exits the defrosting process and enters the normal heating operation process; or

When a plurality of defrosting heat exchangers are defrosted in turn, if the outlet temperature of the defrosting heat exchangers is greater than or equal to the first temperature preset value and maintained for a certain period of time, the defrosting heat exchangers exit the defrosting process process and enter the normal heating operation process;

When multiple defrosting heat exchangers are combined to perform combined rotating defrosting, if the outlet temperature of each of all the defrosting heat exchangers that are defrosting at the same time is greater than or equal to the first temperature preset value and maintained for a certain period of time, the The defrosted defrosting heat exchanger exits the defrosting process and enters the normal heating operation process.
The air conditioner according to claim 5, wherein the defrosting heat exchanger exits the defrosting process and enters a normal heating operation process, comprising at least:

controlling the defrosting switching device so that the gas side of the defrosting heat exchanger communicates with the gas-liquid separator;

Control the opening of the liquid pipe throttling device in communication with the defrosting heat exchanger.
The air conditioner according to any one of claims 1 to 4, wherein,

The target defrost pressure range is related to ambient temperature.
The air conditioner according to claim 1, wherein the air conditioner further comprises:

A plurality of first switching valves connected in parallel, each corresponding to one indoor unit, the first switching valve is used to branch at least part of the refrigerant from the compressor switched by the flow path switching device of each outdoor unit module, and flow into the corresponding the gas side of the indoor heat exchanger in the indoor unit;

A plurality of second switching valves are connected in parallel, each of which corresponds to an indoor unit, one end of the second switching valve is connected to the position where the first switching valve is connected to the gas side of the indoor heat exchanger, and the other end is connected to each outdoor unit. The gas-liquid separator connection of the engine module;

Each of the first switching valve and the second switching valve is controlled by the control device, respectively.
The air conditioner according to any one of claims 1 to 4 and 8, wherein the outdoor unit module further comprises:

two outdoor fans, each of which corresponds to two outdoor heat exchangers and is connected to the control device, and each outdoor fan and its corresponding outdoor heat exchanger respectively form a wind field;

Separation devices, which are used to separate adjacent wind farms;

During defrosting, the control device controls to turn off the outdoor fan corresponding to the defrosting heat exchanger.
The air conditioner according to claim 9, wherein,

When one outdoor heat exchanger in each outdoor unit module is being defrosted, the rotational speed of the outdoor fan corresponding to the other outdoor heat exchanger in the outdoor unit module is increased.