阅读说明：本技术 空调器 (Air conditioner ) 是由 张恒 周敏 邓玉平 高永坤 李廷宇 于 2020-11-30 设计创作，主要内容包括：本发明公开了空调器,包括：至少一个室内机；一个室外机模块,包括：压缩机；流路切换装置；两个室外换热器；两个液管节流装置；两个气侧阀,其各自连接流路切换装置和各室外换热器气侧；除霜支路,其将压缩机排出的制冷剂的一部分分支,并对应选择两个室外换热器中的一个而使制冷剂流入；两个节流装置,其各自一端连接对应室外换热器的主气管,另一端连接对应另一室外换热器的液管节流装置连接在另一室外换热器主液管的位置处。本发明能够在保持空调系统的不间断制热及室内机能力最大化的同时,对除霜换热器控压除霜,提升除霜效率室内热舒适性。(The invention discloses an air conditioner, comprising: at least one indoor unit; an outdoor unit module comprising: a compressor; a flow path switching device; two outdoor heat exchangers; two liquid pipe throttling devices; two air side valves, each of which connects the flow path switching device and the air side of each outdoor heat exchanger; a defrosting branch line which branches a part of the refrigerant discharged from the compressor and selects one of the two outdoor heat exchangers corresponding thereto to allow the refrigerant to flow therein; and one end of each of the two throttling devices is connected with the main air pipe corresponding to the outdoor heat exchanger, and the other end of each of the two throttling devices is connected with the liquid pipe throttling device corresponding to the other outdoor heat exchanger and is connected with the position of the main liquid pipe of the other outdoor heat exchanger. The invention can control the pressure of the defrosting heat exchanger to defrost and improve the defrosting efficiency and indoor thermal comfort while keeping the uninterrupted heating and indoor machine capability of the air conditioning system to be maximized.)

1. An air conditioner, comprising:

at least one indoor unit;

an outdoor unit module comprising:

a compressor;

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

two outdoor heat exchangers arranged in parallel;

two liquid pipe throttling devices which are respectively connected with each outdoor heat exchanger and the indoor unit;

two air side valves each connecting the flow path switching device and the air side of each outdoor heat exchanger;

a defrosting branch line that branches a part of the refrigerant discharged from the compressor and selects one of the two outdoor heat exchangers corresponding thereto to allow the refrigerant to flow therein;

two throttling devices, one end of each throttling device is connected with a main air pipe corresponding to the outdoor heat exchanger, and the other end of each throttling device is connected with a liquid pipe throttling device corresponding to the other outdoor heat exchanger and is connected to the position of a main liquid pipe of the other outdoor heat exchanger;

the control device controls each flow path switching device, each gas side valve, each liquid pipe throttling device, each throttling device and each defrosting branch, and alternately defrosts the outdoor heat exchangers to be defrosted, so that one outdoor heat exchanger to be defrosted is used as a defrosting heat exchanger to be executed, and the other outdoor heat exchanger is used as an evaporator to be executed;

when the defrosting is performed by turns, the control device controls the flow path switching device to be powered on; controlling the defrosting branch to enable the refrigerant discharged by the compressor to be communicated with a liquid side pipe of the defrosting heat exchanger; controlling to close a gas side valve and a liquid pipe throttling device which are communicated with the defrosting heat exchanger; and controlling to open a throttling device connected with the air pipe side of the defrosting heat exchanger.

2. The air conditioner according to claim 1,

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

controlling and opening a throttling device connected with the defrosting heat exchanger, and controlling and adjusting the opening of the throttling device according to the outlet supercooling degree of the defrosting heat exchanger and the target outlet supercooling degree range;

and controlling and adjusting the amount of the refrigerant of a part of the refrigerant discharged by the compressor entering the liquid pipe side of the defrosting heat exchanger according to the defrosting pressure and the target defrosting pressure range.

3. The air conditioner according to claim 2,

controlling and opening the throttling device, and controlling and adjusting the opening degree of the throttling device according to the outlet supercooling degree of the defrosting heat exchanger and the target outlet supercooling degree range, wherein the method specifically comprises the following steps:

setting the supercooling degree range of the target outlet;

calculating the supercooling degree of the outlet of the defrosting heat exchanger;

comparing whether the outlet supercooling degree is within the target outlet supercooling degree range, if so, keeping the current opening degree of the throttling device, and if not, adjusting the opening degree of the throttling device;

controlling and adjusting the amount of the refrigerant entering the liquid pipe side of the defrosting heat exchanger from a part of the refrigerant discharged by the compressor according to the defrosting pressure and the target defrosting pressure range, specifically:

setting a target defrosting pressure range;

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

and comparing whether the defrosting pressure is within the target defrosting pressure range, if so, keeping the amount of the refrigerant passing through the defrosting branch, and if not, adjusting the amount of the refrigerant of a part of the refrigerant discharged by the compressor entering the liquid pipe side of the defrosting heat exchanger.

4. The air conditioner according to claim 3,

adjusting the opening degree of the throttling device, specifically:

when the outlet supercooling degree is larger than the upper limit value of the target outlet supercooling degree range, increasing the opening degree of the throttling device;

when the outlet supercooling degree is smaller than the lower limit value of the target outlet supercooling degree range, reducing the opening degree of the throttling device;

adjusting the amount of refrigerant passing through the defrost branch, specifically:

reducing an amount of refrigerant of a portion of refrigerant discharged from the compressor entering a liquid pipe side of the defrost heat exchanger when the defrost pressure is greater than an upper limit value of the target defrost pressure range;

increasing an amount of refrigerant of a portion of refrigerant discharged by the compressor entering a liquid pipe side of the defrost heat exchanger when the defrost pressure is less than a lower limit of the target defrost pressure range.

5. The air conditioner according to any one of claims 1 to 4,

when defrosting the defrosting heat exchanger, if the first preset defrosting time is reached, or

And if the outlet temperature of the defrosting heat exchanger is greater than or equal to a first temperature preset value and is maintained for a certain time period, the defrosting heat exchanger exits the defrosting process and enters a normal heating operation process.

6. The air conditioner according to any one of claims 2 to 4,

the target defrost pressure range is related to an ambient temperature.

7. The air conditioner as claimed in claim 1, wherein each outdoor heat exchanger includes:

a heat exchanger body;

the first shunt assembly and the second shunt assembly are positioned on the liquid side of the heat exchanger body in parallel, the wind speed of the part of the heat exchanger body corresponding to the first shunt assembly is higher than the wind speed of the part of the heat exchanger body corresponding to the second shunt head, and the free end of the first shunt assembly and the free end of the second shunt assembly are respectively connected with a main liquid pipe of the outdoor heat exchanger;

a first orifice member disposed in the conduit between the free end of the second diverter assembly and the main pipe.

8. The air conditioner according to any one of claims 1 to 4 and 7, further comprising a subcooler, and comprising:

a main path refrigerant passage forming a refrigeration cycle main path with the compressor, the outdoor heat exchanger, and the indoor unit;

the second throttling element is connected to a gas supplementing return pipe, and one end of the gas supplementing return pipe is connected with the upstream or downstream of the main refrigerant channel;

and one end of the auxiliary refrigerant channel is connected with the other end of the air replenishing return pipeline, and the other end of the auxiliary refrigerant channel is connected with the compressor or the gas-liquid separator.

9. The air conditioner of any one of claims 1 to 4 and 7, wherein the outdoor unit module further comprises:

the two outdoor fans respectively correspond to the two outdoor heat exchangers and are connected with the control device, and each outdoor fan and the corresponding outdoor heat exchanger form an air field;

a separation device for separating adjacent wind farms;

and when the defrosting is performed by turns, the control device controls to close the outdoor fan corresponding to the defrosting heat exchanger.

10. The air conditioner according to claim 9,

and when one outdoor heat exchanger in the outdoor unit module is defrosting, the rotating speed of an outdoor fan corresponding to the other outdoor heat exchanger in the outdoor unit module is increased.

Technical Field

The invention relates to the technical field of air conditioners, in particular to an air conditioner.

Background

The technology of the air source heat pump multi-split air conditioner is mature day by day, and the air source heat pump multi-split air conditioner is widely applied to the fields of household and business. The air source heat pump multi-split air conditioner comprises at least one indoor unit and at least one outdoor unit module, wherein when the number of the indoor units is two or more, the indoor units are arranged in parallel, each indoor unit is provided with an indoor heat exchanger and a corresponding indoor fan, when the number of the outdoor unit modules is two or more, the outdoor unit modules are arranged in parallel, each outdoor unit module is provided with a variable frequency compressor, a four-way valve, a throttling element, at least one outdoor heat exchanger and an outdoor fan, which are communicated through a connecting pipeline, and when the number of the outdoor heat exchangers is at least two, the outdoor heat exchangers are arranged in parallel.

The air source heat pump has a big problem in heating operation: when outdoor temperature and humidity reach certain conditions, outdoor heat exchanger air side can frost, and along with the increase of the volume of frosting, the evaporimeter surface can be blockked up gradually, leads to outdoor heat exchanger surface heat transfer coefficient to reduce, and the gas flow resistance increases, seriously influences the machine effect of heating, consequently, the unit needs regularly to defrost.

At present, a reverse defrosting mode is mostly adopted, the reversing is mainly realized by opening a four-way valve, an outdoor unit is switched into a condenser, the defrosting is realized by utilizing the sensible heat and the latent heat of condensation of a high-temperature and high-pressure refrigerant, the defrosting speed is high, and the reliability is good. However, when defrosting is performed, heating operation is stopped, and heat is absorbed from the indoor space due to the fact that the indoor heat exchanger is switched to the evaporator, so that the indoor temperature is obviously reduced, and indoor thermal comfort is seriously affected.

In order to solve the problems, hot gas bypass defrosting is arranged, namely, the exhaust gas of a compressor is led into an outdoor heat exchanger to be defrosted by using a bypass branch to defrost under the condition that the flow direction of a system refrigerant is not changed.

This defrosting mode has the following disadvantages: 1. the heat converted by the power consumption of the compressor is utilized for defrosting, which belongs to low-pressure defrosting, and the heat is less and the defrosting time is long; 2. when the hot gas bypass defrosting is carried out, low-pressure sensible heat is utilized for defrosting, the temperature is lower, the heat exchange temperature difference with a frost layer is small, and the defrosting reliability is poor; 3. although the flow direction of the refrigerant is not changed during defrosting, the flow rate of the refrigerant of the indoor unit is very small, the system does not supply heat to the indoor unit, the indoor temperature is reduced during defrosting, and the user comfort is poor.

Disclosure of Invention

The embodiment of the invention provides an air conditioner, which can control the pressure and defrost of a defrosting heat exchanger while keeping the uninterrupted heating of an air conditioning system and the maximization of the capacity of an indoor unit, and can improve the defrosting efficiency and the indoor thermal comfort.

In order to realize the purpose of the invention, the invention is realized by adopting the following technical scheme:

the application relates to an air conditioner, its characterized in that includes:

at least one indoor unit;

an outdoor unit module comprising:

a compressor;

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

two outdoor heat exchangers arranged in parallel;

two liquid pipe throttling devices which are respectively connected with each outdoor heat exchanger and the indoor unit;

two air side valves each connecting the flow path switching device and the air side of each outdoor heat exchanger;

a defrosting branch line that branches a part of the refrigerant discharged from the compressor and selects one of the two outdoor heat exchangers corresponding thereto to allow the refrigerant to flow therein;

two throttling devices, one end of each throttling device is connected with a main air pipe corresponding to the outdoor heat exchanger, and the other end of each throttling device is connected with a liquid pipe throttling device corresponding to the other outdoor heat exchanger and is connected to the position of a main liquid pipe of the other outdoor heat exchanger;

the control device controls each flow path switching device, each gas side valve, each liquid pipe throttling device, each throttling device and each defrosting branch, and alternately defrosts the outdoor heat exchangers to be defrosted, so that one outdoor heat exchanger to be defrosted is used as a defrosting heat exchanger to be executed, and the other outdoor heat exchanger is used as an evaporator to be executed;

when the defrosting is performed by turns, the control device controls the flow path switching device to be powered on; controlling the defrosting branch to enable the refrigerant discharged by the compressor to be communicated with a liquid side pipe of the defrosting heat exchanger; controlling to close a gas side valve and a liquid pipe throttling device which are communicated with the defrosting heat exchanger; and controlling to open a throttling device connected with the air pipe side of the defrosting heat exchanger.

The application relates to an air conditioner, when the air conditioner carries out the defrosting by turns, controlling means control flow path auto-change over device, each liquid pipe throttling arrangement, each gas side valve, each throttling arrangement and each branch road that defrosts, when an outdoor heat exchanger defrosts, another outdoor heat exchanger that belongs to same off-premises station module with can form the heating cycle with the indoor set, realize the incessant heating of defrosting while, promote user's thermal comfort, and indoor temperature can rise fast after defrosting.

In the present application, in defrosting the defrosting heat exchanger, the control device is configured to:

controlling and opening a throttling device connected with the defrosting heat exchanger, and controlling and adjusting the opening of the throttling device according to the outlet supercooling degree of the defrosting heat exchanger and the target outlet supercooling degree range;

and controlling and adjusting the amount of the refrigerant of a part of the refrigerant discharged by the compressor entering the liquid pipe side of the defrosting heat exchanger according to the defrosting pressure and the target defrosting pressure range.

In this application, control is opened throttling arrangement, according to defrosting heat exchanger's export supercooling degree and target export supercooling degree scope, control adjustment throttling arrangement's aperture specifically is:

setting the supercooling degree range of the target outlet;

calculating the supercooling degree of the outlet of the defrosting heat exchanger;

and comparing whether the outlet supercooling degree is within the target outlet supercooling degree range, if so, keeping the current opening degree of the throttling device, and if not, adjusting the opening degree of the throttling device.

In the present application, the controlling and adjusting the amount of the refrigerant, which is a part of the refrigerant discharged from the compressor and enters the liquid pipe side of the defrosting heat exchanger, according to the defrosting pressure and the target defrosting pressure range, specifically includes:

setting a target defrosting pressure range;

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

and comparing whether the defrosting pressure is within the target defrosting pressure range, if so, keeping the amount of the refrigerant passing through the defrosting branch, and if not, adjusting the amount of the refrigerant of a part of the refrigerant discharged by the compressor entering the liquid pipe side of the defrosting heat exchanger.

In this application, the opening degree of the throttling device is adjusted, specifically:

when the outlet supercooling degree is larger than the upper limit value of the target outlet supercooling degree range, increasing the opening degree of the throttling device;

and when the outlet supercooling degree is smaller than the lower limit value of the target outlet supercooling degree range, reducing the opening degree of the throttling device.

In this application, the amount of refrigerant passing through the defrost branch is adjusted, specifically:

reducing an amount of refrigerant of a portion of refrigerant discharged from the compressor entering a liquid pipe side of the defrost heat exchanger when the defrost pressure is greater than an upper limit value of the target defrost pressure range;

increasing an amount of refrigerant of a portion of refrigerant discharged by the compressor entering a liquid pipe side of the defrost heat exchanger when the defrost pressure is less than a lower limit of the target defrost pressure range.

In the application, when defrosting the defrosting heat exchanger, if the first preset defrosting time is reached, or

And if the outlet temperature of the defrosting heat exchanger is greater than or equal to a first temperature preset value and is maintained for a certain time period, the defrosting heat exchanger exits the defrosting process and enters a normal heating operation process.

In this application, the target defrost pressure range is related to the ambient temperature.

In the present application, each outdoor heat exchanger includes:

a heat exchanger body;

the first shunt assembly and the second shunt assembly are positioned on the liquid side of the heat exchanger body in parallel, the wind speed of the part of the heat exchanger body corresponding to the first shunt assembly is higher than the wind speed of the part of the heat exchanger body corresponding to the second shunt head, and the free end of the first shunt assembly and the free end of the second shunt assembly are respectively connected with a main liquid pipe of the outdoor heat exchanger;

a first orifice member disposed in the conduit between the free end of the second diverter assembly and the main pipe.

In the present application, the air conditioner further includes a subcooler, and includes:

a main path refrigerant passage forming a refrigeration cycle main path with the compressor, the outdoor heat exchanger, and the indoor unit;

the second throttling element is connected to a gas supplementing return pipe, and one end of the gas supplementing return pipe is connected with the upstream or downstream of the main refrigerant channel;

and one end of the auxiliary refrigerant channel is connected with the other end of the air replenishing return pipeline, and the other end of the auxiliary refrigerant channel is connected with the compressor or the gas-liquid separator.

In this application, the outdoor unit module further includes:

the two outdoor fans respectively correspond to the two outdoor heat exchangers and are connected with the control device, and each outdoor fan and the corresponding outdoor heat exchanger form a wind field;

a separation device for separating adjacent wind farms;

and when the defrosting is performed by turns, the control device controls to close the outdoor fan corresponding to the defrosting heat exchanger.

In this application, when one outdoor heat exchanger in the outdoor unit module is defrosting, the rotating speed of an outdoor fan corresponding to another outdoor heat exchanger in the outdoor unit module is increased.

Other features and advantages of the present invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a system structure diagram of an embodiment of an air conditioner according to the present invention;

fig. 2 is a system configuration view of another embodiment of an air conditioner according to the present invention;

fig. 3 is a system configuration view of still another embodiment of an air conditioner according to the present invention;

FIG. 4 is a flow chart of an embodiment of the air conditioner of the present invention during a defrost heat exchanger defrosting when in a rotating defrost mode of operation;

fig. 5 is a system configuration view of still another embodiment of an air conditioner according to the present invention;

fig. 6 is a structural view of an outdoor heat exchanger in still another embodiment of an air conditioner according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

In the description of the present invention, it should be noted that the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected unless otherwise explicitly stated or limited. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art. In the foregoing description of embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

[ basic operation principle of air conditioner ]

A refrigeration cycle of an air conditioner includes a compressor, a condenser, an expansion valve, and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation, and supplies refrigerant to the air that has been conditioned and heat-exchanged.

The compressor compresses a 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 heat is released to the surrounding environment through the condensation process.

The expansion valve expands the liquid-phase refrigerant in a high-temperature and high-pressure state 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 a cooling effect by heat-exchanging with a material to be cooled using latent heat of evaporation of a refrigerant. The air conditioner can adjust the temperature of the indoor space throughout the cycle.

The outdoor unit of an air conditioner refers to a portion including a compressor of a refrigeration cycle and includes an outdoor heat exchanger, the indoor unit of an air conditioner includes an indoor heat exchanger, and an expansion valve may be provided in the indoor unit or the outdoor unit of an air conditioner.

The indoor heat exchanger and the outdoor heat exchanger serve as a condenser or an evaporator. When the indoor heat exchanger is used as a condenser, the air conditioner is used as a heater in a heating mode, and when the indoor heat exchanger is used as an evaporator, the air conditioner is used as a cooler in a cooling mode.

[ air-conditioner ]

In the present application, the outdoor unit module is similar to the air conditioning outdoor unit as described above.

The air conditioner of this application design is many online air conditioners.

The air conditioner includes at least one indoor unit, which are arranged in parallel.

Each indoor unit includes indoor heat exchangers 11-1 and 11-2, respectively (i.e., the indoor heat exchangers as described above), and an indoor fan (not shown) for blowing cold or hot air generated by the indoor heat exchangers 11-1 and 11-2, respectively, toward an indoor space.

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

The air conditioner may include at least one outdoor unit module, and the outdoor unit modules are arranged in parallel.

The application mainly relates to an outdoor unit module which comprises a compressor, a flow path switching device, two outdoor heat exchangers arranged in parallel, two liquid pipe throttling devices, two outdoor fans, a defrosting branch, two gas side valves and a gas-liquid separator.

Referring to fig. 1, the outdoor unit module includes a compressor 1, a check valve 2, a flow path switching device 3, two outdoor heat exchangers 4-1 and 4-2 arranged in parallel, two liquid pipe throttling devices 6-1 and 6-2, two outdoor fans 5-1 and 5-2, a defrosting branch, two gas side valves 20-1 and 20-2, and a gas-liquid separator 14.

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

When the flow switching device 3 is powered off, the default C is connected with the default D, the default S is connected with the default E, the indoor heat exchangers 11-1 and 11-2 are used as evaporators, the outdoor heat exchangers 4-1 and 4-2 are used as condensers, and the air conditioner refrigerates.

When the flow switching device 3 is electrically switched, the C is connected with the S, and the D is connected with the E, so that the indoor heat exchangers 11-1 and 11-2 are used as condensers, the outdoor heat exchangers 4-1 and 4-2 are used as evaporators, and the air conditioner heats.

Referring to fig. 1, the number of the outdoor heat exchangers is the same as that of the outdoor fans and corresponds to one another.

The outdoor unit module has an outdoor heat exchanger 4-1/4-2, an outdoor fan 5-1/5-2, a pipe throttling device 6-1/6-2 connecting a liquid pipe of the indoor heat exchanger 11-1/11-2 and a liquid pipe of the outdoor heat exchanger 4-1/4-2, a gas side valve 20-1/20-2 connected between the gas pipe of the outdoor heat exchanger 4-1/4-2 and the flow path switching device 3, a throttling device 19-1 provided between the main gas pipe of the outdoor heat exchanger 4-1 and the position where the liquid pipe throttling device 6-2 is connected to the main liquid pipe of the outdoor heat exchanger 4-2, and a throttling device 19-2 provided between the main gas pipe of the outdoor heat exchanger 4-2 and the position where the liquid pipe throttling device 6-1 is connected to the main liquid pipe of the outdoor heat exchanger 4-1.

After a part of the refrigerant discharged from the compressor 1 is branched, it does not flow into the outdoor heat exchangers 4-1 and 4-2 through the defrost branch, respectively, at the same time, i.e., it flows into the outdoor heat exchangers 4-1 and 4-2 by turns.

Referring to fig. 1, a defrost branch 18-1 'is provided on a pipe between a discharge port of a compressor 1 and a liquid pipe side of an outdoor heat exchanger 4-1, and a defrost branch 18-2' is provided on a pipe between a discharge port of the compressor 1 and a liquid pipe side of an outdoor heat exchanger 4-2.

A gas pipe throttling device 18-1 is provided on the defrosting branch 18-1' for allowing part of the refrigerant discharged from the compressor 1 to be throttled to a suitable pressure by the gas pipe throttling device 18-1 to enter the outdoor heat exchanger 4-1 for heat exchange defrosting when being turned on.

A gas pipe throttling device 18-2 is provided on the defrosting branch 18-2' for allowing part of the refrigerant discharged from the compressor 1 to be throttled to a suitable pressure by the gas pipe throttling device 18-2 to enter the outdoor heat exchanger 4-2 for heat exchange defrosting when turned on.

In order to prevent the refrigerant flowing through the indoor heat exchangers 11-1 and 11-2 from being heat-exchanged and then flowing into the outdoor heat exchangers 4-1 and 4-2 when the outdoor heat exchanger 4-1 and 4-2 is defrosted without interruption, one ends of the defrosting branches 18-1 'and 18-2' are respectively formed at the discharge port of the compressor 1 (specifically, the discharge port of the check valve 2), the other end of the defrosting branch 18-1 'is connected to the position where the liquid-pipe throttling device 6-1 is connected to the main liquid pipe of the outdoor heat exchanger 4-1, and the other end of the defrosting branch 18-2' is connected to the position where the liquid-pipe throttling device 6-2 is connected to the main liquid pipe of the outdoor heat exchanger 4-2.

One end of the throttling device 19-1 is connected with a main air pipe of the outdoor heat exchanger 4-1, and the other end is arranged on a pipeline between a junction position of the defrosting branch pipe 18-2' and a main liquid pipe of the outdoor heat exchanger 4-2 and the liquid pipe throttling device 6-2.

One end of the throttling device 19-2 is connected with the main air pipe of the outdoor heat exchanger 4-2, and the other end is arranged on a pipeline between the junction position of the defrosting branch pipe 18-1' and the main liquid pipe of the outdoor heat exchanger 4-1 and the liquid pipe throttling device 6-1.

The control device is used for controlling the on-off of the flow path switching device 3, the air side valves 20-1 and 20-2, the liquid pipe throttling devices 6-1 and 6-2, the throttling devices 19-1 and 19-2 and the defrosting branches 18-1 'and 18-2' in the outdoor unit module (namely controlling the on-off of the air pipe throttling devices 18-1 and 18-2).

In the present application, the air-side valves 20-1 and 20-2 are controllable valves such as solenoid valves and large-diameter two-way valves (e.g., reversible two-way valves with extremely small resistance), but do not have a throttling function.

The liquid pipe throttling device 6-1/6-2, the throttling device 19-1/19-2, the indoor side liquid pipe throttling device 10-1/10-2 and the air pipe throttling devices 18-1 and 18-2 can adopt an electronic expansion valve, a bidirectional thermal expansion valve and the like.

Referring to fig. 2 and 3, each of which shows the structure of an air conditioner including the subcooler 7.

The subcooler 7 can be a plate heat exchanger or a sleeve heat exchanger and is used for improving the heating energy efficiency of the air conditioning unit.

Referring to fig. 2 and 3, the subcooler 7 includes a main path refrigerant passage and an auxiliary path refrigerant passage.

The main refrigerant passage includes a first port a1 and a second port a2, the first port a1 is connected to the indoor side, and the second port a2 is connected to the outdoor side.

Referring to fig. 2, the sub refrigerant passage includes a first port b1 and a second port b2, and the first port b1 communicates with the supplementary air port of the compressor 1 through the solenoid valve 17 or communicates with the gas-liquid separator 14 through the solenoid valve 16.

The air make-up return pipe connects the first port a1 of the main refrigerant channel and the second port b2 of the auxiliary refrigerant channel.

A throttle 15 is provided on the air supply return line.

Referring to fig. 3, the air make-up return line may also connect the second port a2 of the main refrigerant channel and the second port b2 of the auxiliary refrigerant channel; and a throttle 15 is provided on the air make-up return line.

The compressor 1, the outdoor heat exchanger 4-1/4-2, the first heat exchange channel of the subcooler 7 and the indoor heat exchanger 11-1/11-2 form a main refrigerant circulation loop.

Referring to fig. 1 to 3, in the air conditioner with the three configurations, there is no difference in the operation modes (i.e., the normal heating operation mode, the normal cooling operation mode, the reverse defrosting operation mode, and the alternate defrosting operation mode) and the control manner of the air conditioner. As described in detail below.

The air conditioner is provided with the subcooler 7, so that air supplement can be performed on the compressor 1, the unit heating energy efficiency can be improved, and the indoor thermal comfort is improved.

[ operation mode of air conditioner ]

The air conditioner has a normal heating operation mode, a normal cooling operation mode, a reverse defrosting operation mode, and a shift defrosting operation mode.

Heating mode of operation in general

The heating operation mode is not different from the common heating operation mode of the air conditioner.

In some embodiments, when the air conditioner is in a normal heating operation mode, referring to fig. 1, the air side valves 20-1 and 20-2 in the outdoor unit module are both opened, the air pipe throttling devices 18-1 and 18-2 are both closed, the liquid pipe throttling devices 6-1 and 6-2 are both opened, the throttling devices 19-1 and 19-2 are both closed, the throttling member 15 is opened, the solenoid valve 17 is opened, the solenoid valve 16 is closed, and the outdoor fans 19-1 and 19-2 are both opened.

In some embodiments, the flow switching device 3 is electrically switched to connect D and E and C and S, the compressor 1 compresses the low-temperature and low-pressure refrigerant into a high-temperature and high-pressure state, and the refrigerant discharged from the compressor 1 passes through the check valve 2 and D and E and enters the indoor heat exchangers 11-1 and 11-2 through the gas side stop valve 13 and the first extension pipe 12.

After heat exchange in the indoor heat exchangers 11-1 and 11-2, condensation heat release is carried out to form liquid refrigerant, and then the refrigerant passes through the indoor machine side throttling devices 10-1 and 10-2, the second extension pipe 9 and the liquid side stop valve 8 and enters the liquid pipe throttling devices 6-1 and 6-2 to be throttled to a low-temperature low-pressure gas-liquid state.

The two-phase refrigerant enters the outdoor heat exchangers 4-1 and 4-2 to be evaporated and absorb heat and is changed into a gas state, the refrigerant coming out of the outdoor heat exchangers 4-1 and 4-2 passes through the gas side valves 20-1 and 20-2, enters the gas-liquid separator 14 through C and S, and is finally sucked into the compressor 1 to be compressed, and the heating cycle is completed.

The refrigerant flow in the normal heating operation mode is in the direction indicated by the broken line arrow in fig. 1.

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

Referring to fig. 2, the difference from the general heating operation mode of fig. 1 is as follows.

After heat exchange in the indoor heat exchangers 11-1 and 11-2, the refrigerant is condensed to release heat and becomes liquid refrigerant, and then the refrigerant is divided into two paths.

One path of auxiliary refrigerant enters the low-pressure side of the subcooler 7 after being throttled by the throttling element 15, exchanges heat with the high-pressure side, enters an air supplementing port of the compressor 1 through the electromagnetic valve 17,

The other path of main refrigerant enters a subcooler 7 to exchange heat with the auxiliary refrigerant, and then is throttled to a low-temperature low-pressure gas-liquid two-state through liquid pipe throttling devices 6-1 and 6-2, the two-phase refrigerant enters outdoor heat exchangers 4-1 and 4-2 to be evaporated and absorbed heat and becomes a gas state, the refrigerant coming out of the outdoor heat exchangers 4-1 and 4-2 passes through gas side valves 20-1 and 20-2 and then enters a gas-liquid separator 14 through C and S, and finally is sucked into a compressor 1 to be compressed, and the heating cycle is completed.

Referring to fig. 3, the difference from the general heating operation mode of fig. 1 is as follows.

After heat exchange in the indoor heat exchangers 11-1 and 11-2, the refrigerant is condensed and released to form liquid refrigerant, and then the liquid refrigerant enters the subcooler 7 and is divided into two paths.

One path of auxiliary refrigerant enters the low-pressure side of the subcooler 7 after being throttled by the throttling element 15, exchanges heat with the high-pressure side, enters an air supplementing port of the compressor 1 through the electromagnetic valve 17,

The other path of main refrigerant and the auxiliary refrigerant exchange heat and then are throttled to a low-temperature low-pressure gas-liquid two-state through the liquid pipe throttling devices 6-1 and 6-2, the two-phase refrigerant enters the outdoor heat exchangers 4-1 and 4-2 to be evaporated and absorbed and becomes a gas state, the refrigerant coming out of the outdoor heat exchangers 4-1 and 4-2 passes through the gas side valves 20-1 and 20-2 and then enters the gas-liquid separator 14 through C and S, and finally is sucked into the compressor 1 to be compressed, so that the heating cycle is completed.

Normal cooling mode of operation

The normal cooling operation mode is the same as the normal cooling operation mode of the air conditioner.

In some embodiments, when the air conditioner is in a normal cooling operation mode, referring to fig. 1, both of the air side valves 20-1 and 20-2 in the outdoor unit module are opened, both of the air pipe throttling devices 18-1 and 18-2 are closed, both of the liquid pipe throttling devices 6-1 and 6-2 are opened, both of the throttling devices 19-1 and 19-2 are closed, the throttling member 15 is opened, the solenoid valve 17 is closed, the solenoid valve 16 is opened, and both of the outdoor fans 5-1 and 5-2 are opened.

The flow path switching device 2 is powered off, the default D and C are communicated, the default E and S are communicated, the compressor 1 compresses a low-temperature and low-pressure refrigerant into a high-temperature and high-pressure state, the refrigerant discharged by the compressor 1 passes through the one-way valves 2, the one-way valves D and C, the air-side valves 20-1 and 20-2 and then enters the outdoor heat exchangers 4-1 and 4-2.

After heat exchange of the outdoor heat exchangers 4-1 and 4-2, condensation heat release is carried out to form liquid refrigerant, and then the refrigerant is throttled by the liquid pipe throttling devices 6-1 and 6-2, passes through the liquid side stop valve 8 and the second extension pipe 9, enters the indoor heat exchangers 11-1 and 11-2 to be evaporated and absorbed heat and is changed into gas state.

The refrigerants discharged from the indoor heat exchangers 11-1 and 11-2 pass through the first extension pipe 12, the gas side stop valve 13, and the four-way valves E and S, enter the gas-liquid separator 14, and are finally sucked into the compressor 1 to be compressed, thereby completing the refrigeration cycle.

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

Referring to fig. 2, the difference from the normal cooling operation mode of fig. 1 is as follows.

The refrigerant throttled by the liquid pipe throttling devices 6-1 and 6-2 enters the subcooler 7 and then is divided into two paths.

One path of auxiliary path refrigerant enters the subcooler 7 through the throttling element 15, exchanges heat with the main path refrigerant and then enters the gas-liquid separator 14 through the electromagnetic valve 16.

One path of main path refrigerant passes through the liquid side stop valve 8 and the second extension pipe 9, enters the indoor heat exchangers 11-1 and 11-2 to be evaporated and absorbed heat, and is changed into a gaseous state, and the refrigerant coming out of the indoor heat exchangers 11-1 and 11-2 enters the gas-liquid separator 14 through the first extension pipe 12, the gas side stop valve 13 and E and S of the four-way valve, and is finally sucked into the compressor 1 to be compressed, so that the refrigeration cycle is completed.

Referring to fig. 3, the difference from the normal cooling operation mode of fig. 1 is as follows.

The refrigerant throttled by the liquid pipe throttling devices 6-1 and 6-2 is divided into two paths.

One path of auxiliary path refrigerant enters the subcooler 7 through the throttling element 15, exchanges heat with the main path refrigerant and then enters the gas-liquid separator 14 through the electromagnetic valve 16.

One path of main path refrigerant passes through the liquid side stop valve 8 and the second extension pipe 9, enters the indoor heat exchangers 11-1 and 11-2 to be evaporated and absorbed heat, and is changed into a gaseous state, and the refrigerant coming out of the indoor heat exchangers 11-1 and 11-2 enters the gas-liquid separator 14 through the first extension pipe 12, the gas side stop valve 13 and E and S of the four-way valve, and is finally sucked into the compressor 1 to be compressed, so that the refrigeration cycle is completed.

Reverse defrost mode of operation

When the control device of the air conditioner detects and judges that the outdoor heat exchanger 4-1 and/or 4-2 needs defrosting, the compressor 1 firstly reduces the frequency or directly stops, and the indoor fan and the outdoor fan stop running.

Then, the four-way valve is powered off and reversed, the compressor 1 is started, the outdoor heat exchangers 4-1 and 4-2 are used as condensers to perform defrosting, namely heating of all indoor units is stopped, and defrosting is performed on all the outdoor heat exchangers 4-1 and 4-2.

After the defrosting is completed, the air conditioner reenters the normal heating operation mode.

The reverse defrosting operation mode has the advantages of clean defrosting, but also has a plurality of defects (1) that the heating operation is stopped during defrosting, the indoor temperature is obviously reduced, and the use comfort of users is influenced; (2) during defrosting, the flow direction of the refrigerant needs to be changed, and particularly during heating operation after defrosting, because a large amount of refrigerant is stored in the gas-liquid separator 14 during defrosting, the high-low pressure difference is slowly established after defrosting, the heating capacity is low, and the heating cycle capacity is seriously influenced.

Alternate defrost mode of operation

The alternate defrosting operation mode is operated under the conditions that the outdoor heat exchanger needs to be defrosted and the indoor unit still needs to have certain heating capacity, so that the air conditioner can keep heating continuously while the outdoor heat exchanger to be defrosted (namely, the defrosting heat exchanger) is defrosted, the fluctuation of indoor temperature is reduced, and the heating comfort of a user is enhanced.

And in the defrosting process, the defrosting pressure of the defrosting heat exchanger is controlled, the latent heat of the refrigerant is utilized for defrosting, compared with hot gas bypass defrosting, sensible heat defrosting is utilized, the defrosting efficiency is high, the defrosting time is short, the heat acquired by the indoor unit is large, and the user comfort level is high.

When the two outdoor heat exchangers in the outdoor unit module are defrosted, the two outdoor heat exchangers to be defrosted execute a rotation defrosting operation mode, namely only one of the two outdoor heat exchangers 4-1 and 4-2 can be selected to defrost at the same time, and the other outdoor heat exchanger is used as an evaporator to execute defrosting.

When the outdoor heat exchangers 4-1 and 4-2 are alternately defrosted, the defrosting process is started according to defrosting conditions, defrosting is started according to a preset sequence, and the control device controls the defrosting heat exchanger and the rest of the outdoor heat exchangers in the defrosting process.

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

In some embodiments, referring to fig. 1, the rotation of the outdoor heat exchangers 4-1 and 4-2 for defrosting is illustrated.

S1: the process begins.

S2: the air conditioner performs a general heating operation mode.

S3: and judging whether the outdoor heat exchangers 4-1 and 4-2 meet defrosting conditions, if so, entering S4, and if not, continuing to execute a normal heating operation mode of S2.

S4: and sequentially executing a rotation defrosting operation mode aiming at the plurality of defrosting heat exchangers.

The outdoor heat exchangers 4-1 and 4-2 are alternately defrosted according to the frosting amount of the outdoor heat exchangers 4-1 and 4-2 to be defrosted.

The outdoor heat exchangers 4-1 and 4-2 can be sequentially defrosted according to the sequence of the frost formation amount from large to small.

The judgment of the frosting amount can be performed by detecting an index indicative of the frosting amount by a detecting means (not shown), for example, at least one of the heating capacity of the outdoor heat exchangers 4-1 and 4-2, the evaporation temperature of the refrigerant, the indoor unit blow-out temperature, the liquid pipe temperature of the outdoor heat exchanger, and the like, and predicting the frosting amount of the outdoor heat exchangers 4-2 and 4-2 according to the variation of the detection value.

For example, the frost formation amount is determined by the liquid pipe temperature of the outdoor heat exchanger, and the frost formation amount increases as the liquid pipe temperature of the outdoor heat exchanger decreases.

If the frosting amount of the outdoor heat exchanger 4-1 is larger than that of the outdoor heat exchanger 4-2, the outdoor heat exchanger 4-1 should be defrosted first to avoid that the normal operation of the outdoor heat exchanger 4-1 is influenced by excessive frosting. The outdoor heat exchanger 4-2 is in a normal heating operation mode at this time.

That is, the outdoor heat exchanger 4-1 is performed as a defrosting heat exchanger, and the outdoor heat exchanger 4-2 is performed as an evaporator.

After the defrosting of the outdoor heat exchanger 4-1 is completed and the normal heating operation mode is entered, the outdoor heat exchanger 4-2 is defrosted.

That is, the switching of the outdoor heat exchanger 4-1 is performed as a defrosting heat exchanger, and the outdoor heat exchanger 4-2 is performed as an evaporator.

In some embodiments, the defrosting may be performed by rotation according to a preset sequence without determining the frosting amount.

After the outdoor heat exchangers 4-1 and 4-2 are alternately defrosted for many times, a reverse defrosting operation mode can be selected to completely defrost the outdoor heat exchangers 4-1 and 4-2. Of course, the reverse defrost mode of operation may be selected under other conditions.

The process of defrosting the defrosting heat exchanger is described as follows.

S41: the control flow path switching device 2 is powered on, the defrosting branch is controlled to enable the refrigerant discharged by the compressor 1 to be communicated with 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 connected with the gas pipe side of the defrosting heat exchanger is controlled to be opened, and the rest outdoor heat exchanger is used as an evaporator to be executed.

The outdoor heat exchanger 4-1 in the outdoor unit module is used as a defrosting heat exchanger to execute, and a defrosting process is started, and the outdoor heat exchanger 4-2 is used as an evaporator to execute, so that a normal heating operation process is kept.

And keeping the flow path switching device 2 powered on, controlling an air pipe throttling device 18-1 on the defrosting branch 18-1' to be opened, closing the outdoor fan 5-1, closing the liquid pipe throttling device 6-1, closing the air side valve 20-1, and opening the throttling device 19-1, wherein the rest devices are kept in the same state as in the normal heating operation mode.

Referring to fig. 1, solid arrows indicate a refrigerant flow direction during a defrosting process of the outdoor heat exchanger 4-1.

When entering the alternate defrosting operation mode, the compressor 1 compresses a 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 passes through the flow switching devices 2D and E, the gas-side shutoff valve 13, and the first extension pipe 12, and enters the indoor heat exchangers 11-1 and 11-2.

After heat exchange in the indoor heat exchangers 11-1 and 11-2, condensation heat release is carried out to form liquid refrigerant, and then the refrigerant enters the liquid pipe throttling device 6-2 to be throttled to a low-temperature low-pressure gas-liquid state through the indoor machine side throttling devices 10-1 and 10-2, the second extension pipe 9 and the liquid side stop valve 8.

And the other part of high-temperature and high-pressure refrigerant is throttled to a proper pressure by the air pipe throttling device 18-1 on the defrosting branch 18-1', and then enters the outdoor heat exchanger 4-1 for heat exchange and defrosting.

The defrosted refrigerant is throttled by the throttling device 19-1, then is merged with the refrigerant throttled by the liquid pipe throttling device 6-2, then enters the outdoor heat exchanger 4-2 together for heat exchange, then enters the gas-liquid separator 14 through the gas side valve 20-2 and the C and S of the flow path switching device 2, and finally is sucked into the compressor 1.

Referring to fig. 2, the difference from the alternate defrost mode of operation of fig. 1 is as follows.

And keeping the flow path switching device 2 powered on, controlling an air pipe throttling device 18-1 on the defrosting branch 18-1' to be opened, closing the outdoor fan 5-1, closing the liquid pipe throttling device 6-1, closing the air side valve 20-1, opening the throttling device 19-1 and the throttling element 15, and keeping the rest devices in the same state as in the normal heating operation mode.

Referring to fig. 2, when entering the shift defrosting mode, the compressor 1 compresses a 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 passes through the flow switching devices 2D and E, the gas-side shutoff valve 13, and the first extension pipe 12, and enters the indoor heat exchangers 11-1 and 11-2.

The refrigerant is condensed and released heat after heat exchange in the indoor heat exchangers 11-1 and 11-2 to become liquid refrigerant, and then the refrigerant is divided into two paths after passing through the indoor machine side throttling devices 10-1 and 10-2, the second extension pipe 9 and the liquid side stop valve 8.

One path of main path refrigerant is throttled to a low-temperature low-pressure gas-liquid two-state through a liquid pipe throttling device 6-2 and then flows out.

The other path of auxiliary refrigerant enters the low-pressure side of the subcooler 7 after being throttled by the throttling element 15, exchanges heat with the high-pressure side and then enters the air supplementing port of the compressor 1 through the electromagnetic valve 17.

And the other part of high-temperature and high-pressure refrigerant is throttled to a proper pressure by the air pipe throttling device 18-1 on the defrosting branch 18-1', and then enters the outdoor heat exchanger 4-1 for heat exchange and defrosting.

The defrosted refrigerant is throttled by the throttling device 19-1, then is merged with the refrigerant throttled by the liquid pipe throttling device 6-2, then enters the outdoor heat exchanger 4-2 together for heat exchange, then enters the gas-liquid separator 14 through the gas side valve 20-2 and the C and S of the flow path switching device 2, and finally is sucked into the compressor 1.

Referring to fig. 3, the difference from the alternate defrost mode of operation of fig. 1 is as follows.

And keeping the flow path switching device 2 powered on, controlling an air pipe throttling device 18-1 on the defrosting branch 18-1' to be opened, closing the outdoor fan 5-1, closing the liquid pipe throttling device 6-1, closing the air side valve 20-1, opening the throttling device 19-1 and the throttling element 15, and keeping the rest devices in the same state as in the normal heating operation mode.

Referring to fig. 3, when entering the shift defrosting mode, the compressor 1 compresses a 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 passes through the flow switching devices 2D and E, the gas-side shutoff valve 13, and the first extension pipe 12, and enters the indoor heat exchangers 11-1 and 11-2.

The refrigerant is condensed and released heat after heat exchange in the indoor heat exchangers 11-1 and 11-2 to become liquid refrigerant, and then enters the subcooler 7 after passing through the indoor machine side throttling devices 10-1 and 10-2, the second extension piping 9 and the liquid side stop valve 8 to be divided into two paths.

One path of main path refrigerant is throttled to a low-temperature low-pressure gas-liquid two-state through a liquid pipe throttling device 6-2 and then flows out.

The other path of auxiliary refrigerant enters the low-pressure side of the subcooler 7 after being throttled by the throttling element 15, exchanges heat with the high-pressure side and then enters the air supplementing port of the compressor 1 through the electromagnetic valve 17.

And the other part of high-temperature and high-pressure refrigerant is throttled to a proper pressure by the air pipe throttling device 18-1 on the defrosting branch 18-1', and then enters the outdoor heat exchanger 4-1 for heat exchange and defrosting.

The defrosted refrigerant is throttled by the throttling device 19-1, then is merged with the refrigerant throttled by the liquid pipe throttling device 6-2, then enters the outdoor heat exchanger 4-2 together for heat exchange, then enters the gas-liquid separator 14 through the gas side valve 20-2 and the C and S of the flow path switching device 2, and finally is sucked into the compressor 1.

In the application, the opening degree of the throttling device 19-1 is controlled and adjusted according to the supercooling degree of the outlet of the outdoor heat exchanger 4-1 and the target supercooling degree range of the outlet, so that the supercooling degree of the outlet of the outdoor heat exchanger 4-1 tends to be maintained in the target supercooling degree range of the outlet.

According to the defrosting pressure of the outdoor heat exchanger 4-1 and the target defrosting pressure range, the opening degree of the air pipe throttling device 18-1 is controlled and adjusted to ensure that the defrosting pressure of the defrosting heat exchanger 4-1 tends to be maintained in the target defrosting pressure range, the defrosting pressure is ensured, the latent heat is utilized for defrosting, the defrosting speed and efficiency are improved, the capacity of an indoor unit is maximized, and the indoor thermal comfort of a user is improved.

In defrosting the outdoor heat exchanger 4-1, how to control the opening degree of the throttle device 19-1 and the opening degree of the air pipe throttle device 18-1 is described in detail with reference to fig. 4.

Before entering the defrosting process, the initial opening degree of the defrosting time throttling device 19-1 and the air pipe throttling device 18-1 needs to be set.

For example, since the pre-defrosting throttle 19-1 and the air pipe throttle 18-1 are both off, it is necessary to set the initial opening degree (e.g., fully open) of the defrosting throttle 19-1 and the opening degree (e.g., fully open) of the air pipe throttle 18-1 before defrosting.

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

In the present application, there is a range for the target outlet supercooling degree Te1sco, for example, 0 ℃ C. ltoreq. Te1 sco. ltoreq.10 ℃.

A target outlet supercooling degree range (Te 1sco- λ, Te1sco + λ) is set, for example, 0 ℃ < λ < 3 ℃ based on the target outlet supercooling degree Te1 sco.

In the present application, 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 when the air conditioner is commissioned.

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

A target defrosting pressure range (Pfo-delta, Pfo + delta) is set based on the target defrosting pressure Pfo, for example, 0MPa < delta < 0.5 MPa.

S2': and calculating the supercooling Te1sc of the outlet of the outdoor heat exchanger 4-1.

The outlet supercooling degree Te1sc of the outdoor heat exchanger 4-1 is calculated by the defrosting pressure Pm (detected by the pressure sensor 222) and the outlet temperature Te1 (detected by the temperature sensor 233) of the outdoor heat exchanger 4-1.

That is, Te1sc = Te1-Tec, where Tec is the corresponding saturation temperature at the defrost pressure Pm, obtainable by prior art inquiry.

S3': comparing whether the outlet supercooling degree Te1sc is in the target outlet supercooling degree range;

s31': if the outlet supercooling degree Te1sc is in the target outlet supercooling degree range, keeping the current opening degree of the throttling device 19-1, and executing to S4'; if not, the current opening degree of the throttle device 19-1 is adjusted, and the process goes to S4'.

The process of specifically adjusting the current opening degree of the throttle device 19-1 is described as follows.

S32': if the outlet supercooling degree Te1sc is greater than the upper limit value of the target outlet supercooling degree range, the opening degree of the throttle device 19-1 is increased by one adjustment step number, and execution is performed to S4'.

That is, the next opening degree EV19-1(n +1) = EV19-1(n) + Δ EV19-1 of the throttle device 19-1, where Δ EV19-1 is the number of adjustment steps, where the number of adjustment steps may be selected to be 0.1% -10% pls (i.e., the number of steps) of the total opening degree.

S33': if the outlet supercooling degree Te1sc is smaller than the lower limit value of the target outlet supercooling degree range, the opening degree of the throttle device 19-1 is decreased by one adjustment step number, and execution is performed to S4'.

That is, the next opening degree EV19-1(n +1) = EV19-1(n) - Δ EV19-1 of the throttle device 19-1, where Δ EV19-1 is the number of adjustment steps, where the number of adjustment steps may be selected to be 0.1% -10% pls (i.e., the number of steps) of the total opening degree.

S4': whether the defrost pressure Pm is within the target defrost pressure range is compared, if so, the amount of refrigerant passing through the defrost branch 18-1 'is maintained, and S42 is performed, and if not, the amount of refrigerant of which a portion of the refrigerant discharged from the compressor 1 enters the liquid pipe side of the defrost heat exchanger 4-1, i.e., the amount of refrigerant passing through the defrost branch 18-1' is adjusted, and S42 is performed.

The amount of refrigerant passing through the defrost branch 18-1 'is adjusted by controlling the opening of the air pipe throttling device 18-1 on the defrost branch 18-1', as follows.

S41': if the defrost pressure Pm is within the target defrost pressure range, the opening degree of the air pipe throttle device 18-1 is maintained, and the process goes to S42.

S42': if the defrost pressure Pm is greater than the upper limit value of the target defrost pressure range, the opening degree of the air pipe throttling device 18-1 is decreased by one adjustment step number, and the process goes to S42.

That is, the next opening degree EV18-1(n +1) = EV18-1(n) - Δ EV18-1 of the tracheal throttle device 18-1, where Δ EV18-1 is the number of adjustment steps, where the number of adjustment steps may be selected to be 0.1% -10% pls (i.e., the number of steps) of the total opening degree.

S43': if the defrost pressure Pm is less than the lower limit value of the target defrost pressure range, the opening degree of the air pipe throttling device 18-1 is increased by one adjustment step number, and the process goes to S42.

That is, the next opening degree EV18-1(n +1) = EV18-1(n) + Δ EV18-1 of the tracheal throttle device 18-1, where Δ EV18-1 is the number of adjustment steps, where the number of adjustment steps may be selected to be 0.1% -10% pls (i.e., the number of steps) of the total opening degree.

S42: and judging whether defrosting is finished or not, if so, exiting the defrosting process, otherwise, returning to S2', and adjusting the opening degrees of the throttling device 19-1 and the air pipe throttling device 18-1 again.

As the defrosting end condition, it may be determined whether the defrosting time period T1 reaches a first preset time T1, or whether the outlet temperature Te1 of the outdoor heat exchanger 4-1 is greater than or equal to a first preset temperature Tef (e.g., 2 ℃ < Tef < 20 ℃) and is maintained for a certain time period T; and if one of the two conditions is met, indicating that the defrosting is finished, otherwise, continuing to judge.

Of course, the defrosting end condition is not limited to this, and for example, it may be determined by using whether or not the air pipe temperature Tg of the outdoor heat exchanger 4-1 is equal to or higher than the set temperature Tn and whether or not the suction pressure Ps of the compressor 1 is equal to or higher than the set pressure Po; alternatively, the number of times of adjustment of the opening degrees of the throttle device 19-1 and the pipe throttle device 18-1, and the like may be used.

Although S3 'is performed before S4' as described above, the order of S3 'and S4' is not limited, i.e., S4 'may also be performed before S3'.

And after the defrosting of the outdoor heat exchanger 4-1 is finished, the defrosting process is quitted, and then the normal heating operation process is carried out.

The outdoor heat exchanger 4-1 exits the defrosting process and enters a normal heating operation process, which comprises the following steps:

(1) controlling the air pipe throttling device 18-1 on the defrosting branch 18-1' to be closed;

(2) opening an outdoor fan 5-1;

(3) opening the pipe throttling device 6-1;

(4) opening the air side valve 20-1;

(5) the throttle device 19-1 is closed.

Thereafter, the outdoor heat exchanger 4-2 serves as a defrosting heat exchanger to enter a defrosting process, and the outdoor heat exchanger 4-1 serves as an evaporator to maintain a normal heating operation process.

The flow path switching device 3 is kept powered on, the air pipe throttling device 18-2 on the defrosting branch 18-2' is controlled to be opened, the throttling device 19-2 is controlled to be opened, the outdoor fan 5-2, the liquid pipe throttling device 6-2 and the air side valve 20-2 are closed, and the rest devices are kept in the same state as in the normal heating operation mode.

The defrosting process of the outdoor heat exchanger 4-2 is referred to the defrosting process of the outdoor heat exchanger 4-1, and is not described herein.

[ isolation of wind field ]

The outdoor unit module is provided with two outdoor fans 5-1 and 5-2 corresponding to the outdoor heat exchangers 4-1 and 4-2, respectively.

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

Since the outdoor fan 5-2 is kept in operation during defrosting of the outdoor heat exchanger 4-1, in order to avoid a situation where the outdoor heat exchanger 4-1 cannot be effectively defrosted due to the wind field generated by the outdoor fan 5-2 blowing through the outdoor heat exchanger 4-1, a partition device (not shown) for partitioning the wind field is provided in the present application (see patent document No. 202010279447.2 entitled "outdoor unit of air conditioner").

The separating device is used for separating the first wind field from the second wind field.

That is, when the outdoor fan 5-1 is operated and the outdoor fan 5-2 is not operated, it does not blow wind to the outdoor heat exchanger 4-2, and when the outdoor fan 5-2 is operated and the outdoor fan 5-1 is not operated, it does not blow wind to the outdoor heat exchanger 4-1.

Thus, when the outdoor heat exchanger 4-1 performs defrosting, the first wind field and the second wind field are separated by the separating device, and therefore, even if the outdoor fan 5-2 still operates, the first wind field is not affected.

Therefore, the situation that the air blows over the surface of the outdoor heat exchanger 4-1 when defrosting is carried out is effectively avoided, the situation that the defrosting cannot be effectively carried out due to overlarge condensation load when the outdoor temperature is low is further prevented, and uninterrupted heating of a full-temperature area can be realized.

In addition, when the outdoor fan 5-1 stops running (namely the outdoor heat exchanger 4-1 is defrosting), the rotating speed of the outdoor fan 5-2 can be properly increased, the heating effect is further enhanced, the indoor temperature fluctuation is reduced, and the heating capacity of the air conditioner and the heating comfort of users are greatly improved.

When the outdoor heat exchanger 4-1 exits the defrosting process and enters a normal heating operation process, the outdoor fan 5-1 is correspondingly turned on and the outdoor fan 5-2 is turned off, and the rotating speed of the outdoor fan 5-1 can be properly increased.

[ Uniform defrosting ]

Fig. 5 shows a block diagram of an embodiment of the outdoor heat exchanger.

Fig. 6 is a system configuration view showing a further embodiment of an air conditioner in which an outdoor heat exchanger is constructed using the outdoor heat exchanger of fig. 5.

Referring to fig. 5, the outdoor heat exchangers 4-1 and 4-2 have the same structure, and the structure of the outdoor heat exchanger 4-1 will be described as an example.

The outdoor heat exchanger 4-1 includes a heat exchanger body 41, a main gas pipe 42 communicating with the heat exchanger body 41, first and second branch assemblies communicating with the heat exchanger body 41, a liquid pipe L1 connected to the first branch assembly, and a liquid pipe L2 connected to the second branch assembly, and merges to form a main liquid pipe 43.

Wherein the main air pipe connecting pipe of the main air pipe 42 is connected to the air side valve 20-1 and one end of the throttle device 19-1.

Wherein the first flow-dividing assembly comprises a first flow-dividing capillary tube 41A communicating with the heat exchanger body 41 and a first flow-dividing head 41A' communicating with the first flow-dividing capillary tube 41A.

The second flow-dividing assembly includes a second flow-dividing capillary tube 41B communicating with the heat exchanger body 41 and a second flow-dividing head 41B' communicating with the second flow-dividing capillary tube 41B.

Liquid pipe L1 connected to first branch head 41A and liquid pipe L2 connected to second branch head 41B' merge to form main liquid pipe 43.

Generally, when the air conditioner is operated for heating in a normal state, a portion 4-1A of the heat exchanger body 41 connected to the first shunting assembly is located at a wind speed greater than a portion 4-1B of the heat exchanger body 41 connected to the second shunting assembly, and thus, the frosting amount of the portion 4-1A of the outdoor heat exchanger 4-1 is smaller than that of the portion 4-1B of the outdoor heat exchanger 4-1.

And based on the air conditioner usually heats, consider that wind field and refrigerant volume match when again, in order to realize the best effect of heating, generally, the resistance of the place capillary that the amount of wind is great can design less for passing more refrigerant volume, and the resistance of the place capillary that the amount of wind is less can design great, so as to pass less refrigerant volume.

That is, the resistance to the portion 4-1A entering the outdoor heat exchanger 4-1 is less than the resistance to the portion 4-1B entering the outdoor heat exchanger 4-1.

When the defrosting is carried out alternately, the frosting amount of the part 4-1A of the outdoor heat exchanger 4-1 is small, the corresponding resistance is small, and the amount of the entering refrigerant is large; the frost formation amount of the part 4-1B of the outdoor heat exchanger 4-1 is large, the corresponding resistance is large, and the entering refrigerant amount is small.

Thus, the defrosting speed of the part 4-1A of the outdoor heat exchanger 4-1 is high, the defrosting speed of the part 4-1B of the outdoor heat exchanger 4-1 is low, the whole defrosting time is prolonged, the refrigerant energy during defrosting is wasted, the defrosting power consumption is increased, and energy is not saved.

For this reason, a throttle 21-1 is provided on the line L2 between the second tap 41B' of the outdoor heat exchanger 4-1 and the main liquid pipe 43.

The throttle member 21-1 is not controlled by the outside, has a constant opening, and may be a throttle capillary having a constant opening, or a combination of a throttle capillary and a check valve, or a combination of a throttle capillary and an electromagnetic valve.

When the air conditioner with the structure of the outdoor heat exchanger 4-1 is in a normal heating operation mode, the throttling element 21-1 is connected with the second shunt capillary tube 41B of the outdoor heat exchanger 4-1 in series, and the resistance of the throttling element is still larger than that of the first shunt capillary tube 41A of the outdoor heat exchanger 4-1, so that the equivalent heating energy-saving resistance effect in the figure 1 can be realized, the heating shunt is ensured to be uniform, and the optimal heating is realized.

When the shift defrosting operation mode is performed as described above, the refrigerant throttled by the air pipe throttling device 18-1 is divided into two paths.

One path of refrigerant enters the heat exchanger body 41 for heat exchange through a first flow dividing head 41A' and a first flow dividing capillary tube 41A of the outdoor heat exchanger 4-1.

The other path of refrigerant enters the heat exchanger body 41 for heat exchange through a second flow dividing head 41B' and a second flow dividing capillary tube 41B of the outdoor heat exchanger 4-1. At this time, since the resistance of the second flow dividing capillary tube 41B is smaller than the sum of the resistance of the orifice 21-1 and the resistance of the first flow dividing capillary tube 41B, the refrigerant in this path flows only to the second flow dividing head 41B'.

Therefore, the air conditioner does not pass through the throttling element 21-1 during defrosting, so that the resistance of the part 4-1B of the outdoor heat exchanger 4-1 entering during defrosting is reduced, the refrigerant flow in the part 4-1B of the outdoor heat exchanger 4-1 is increased, the defrosting speed of the part 4-1B of the outdoor heat exchanger 4-1 is increased, uniform defrosting of the outdoor heat exchanger 4-1 is realized, the integral defrosting speed is increased, the defrosting power consumption is reduced, and energy conservation is realized.

Referring to fig. 5, the defrost branch 18-1'/18-2' branches a portion of the refrigerant discharged from the compressor 1 and selects the outdoor heat exchanger 4-1/4-2 correspondingly, so that the refrigerant flows into the outdoor heat exchanger 4-1 through the first and second taps 41A 'and 41B', respectively.

Generally, the outdoor fan 5-1 is disposed above the outdoor heat exchanger 4-1, and thus, a portion 4-1A of the outdoor heat exchanger 4-1 is an upper portion of the outdoor heat exchanger 4-1, and a portion 4-1B of the outdoor heat exchanger 4-1 is a lower portion of the outdoor heat exchanger 4-1.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions.