阅读说明：本技术 空调器 (Air conditioner ) 是由 张恒 邓玉平 高永坤 郭小惠 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：至少一个室外机模块,各室外机模块包括：压缩机；流路切换装置；并列设置的多个室外换热器；换热器本体的对应第一分流组件的部分所在的风速大于对应第二分流头所在的风速,在第一分流组件和第二分流组件之间的管路上设置第一液管节流装置；多个第二液管节流装置；多个气管节流装置；除霜支路,其将压缩机排出的制冷剂的一部分分支,并对应选择多个室外换热器中的一个而使制冷剂一部分流入所述第二分流组件且另一部分经过所述第一液管节流装置流入所述第一分流组件。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,对除霜换热器进行控压除霜及均匀除霜。(The invention discloses an air conditioner, comprising: at least one outdoor unit module, each outdoor unit module includes: a compressor; a flow path switching device; a plurality of outdoor heat exchangers arranged in parallel; the wind speed of the part of the heat exchanger body corresponding to the first shunt assembly is higher than that of the part corresponding to the second shunt head, and a first liquid pipe throttling device is arranged on a pipeline between the first shunt assembly and the second shunt assembly; a plurality of second fluid conduit restriction means; a plurality of tracheal restriction devices; and a defrosting branch circuit which branches a portion of the refrigerant discharged from the compressor and allows a portion of the refrigerant to flow into the second flow dividing assembly and another portion to flow into the first flow dividing assembly through the first pipe-in-pipe throttling device in response to selection of one of the plurality of outdoor heat exchangers. The invention can control pressure and defrost the defrosting heat exchanger and uniformly defrost 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;

at least one outdoor unit module, each outdoor unit module includes:

a compressor;

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

the heat exchanger comprises a plurality of outdoor heat exchangers arranged in parallel, wherein each outdoor heat exchanger comprises a heat exchanger body, a first shunt assembly and a second shunt assembly which are arranged 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 a first liquid pipe throttling device is arranged on a pipeline between the first shunt assembly and the second shunt assembly;

a plurality of second liquid pipe throttling devices which are respectively connected with the indoor unit and the outdoor heat exchangers;

a plurality of air pipe throttling devices which are respectively connected with the flow path switching device and each outdoor heat exchanger;

a defrosting branch circuit which branches a part of the refrigerant discharged from the compressor and allows a part of the refrigerant to flow into the second flow dividing assembly and another part to flow into the first flow dividing assembly through the first pipe-in-pipe throttling means in response to selection of one of the plurality of outdoor heat exchangers;

the control device controls each flow path switching device, each second liquid pipe throttling device, each air pipe throttling device and each defrosting branch when the plurality of outdoor heat exchangers need defrosting, and alternately defrosts each outdoor heat exchanger to be defrosted, so that the outdoor heat exchanger to be defrosted is used as a defrosting heat exchanger to be defrosted and the rest outdoor heat exchangers are used as evaporators to be operated;

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 liquid pipe throttling device communicated with the defrosting heat exchanger; and controlling to open the air pipe throttling device.

2. The air conditioner according to claim 1,

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

controlling and opening the air pipe throttling device, and controlling and adjusting the opening degree of the air pipe throttling device communicated with the air side of the defrosting heat exchanger according to the exhaust superheat degree of the compressor and the target superheat degree range;

and controlling and adjusting the amount of the refrigerant of which one part of the refrigerant discharged by the compressor enters the liquid side pipe 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 air pipe throttling device, and controlling and adjusting the opening degree of the air pipe throttling device communicated with the air side of the defrosting heat exchanger according to the exhaust superheat degree and the target superheat degree range of the compressor, wherein the method specifically comprises the following steps:

setting a target exhaust superheat range of the compressor;

calculating the discharge superheat degree of the compressor;

comparing whether the exhaust superheat degree is within the target exhaust superheat degree range, if so, keeping the current opening degree of the air pipe throttling device, and if not, adjusting the opening degree of the air pipe throttling device;

controlling and adjusting the amount of the refrigerant, which is a part of the refrigerant discharged by the compressor and enters the liquid side pipe of the defrosting heat exchanger, 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 in the target defrosting pressure range, if so, keeping the amount of the refrigerant of a part of the refrigerant discharged by the compressor entering a liquid side pipe of the defrosting heat exchanger, and if not, adjusting the amount of the refrigerant of the part of the refrigerant discharged by the compressor entering the liquid side pipe of the defrosting heat exchanger.

4. The air conditioner according to claim 3,

adjusting the opening degree of the air pipe throttling device, specifically:

when the exhaust superheat degree is larger than the upper limit value of the target exhaust superheat degree range, increasing the opening degree of the air pipe throttling device;

when the exhaust superheat degree is smaller than the lower limit value of the target exhaust superheat degree range, reducing the opening degree of the air pipe throttling device;

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

when the defrosting pressure is larger than the upper limit value of the target defrosting pressure range, reducing the amount of refrigerant of a part of refrigerant discharged by the compressor entering a liquid side pipe of the defrosting heat exchanger;

when the defrosting pressure is less than the lower limit value of the target defrosting pressure range, the amount of the refrigerant of which a part of the refrigerant discharged by the compressor enters a liquid side pipe of the defrosting heat exchanger is increased.

5. The air conditioner according to any one of claims 1 to 4, wherein the control device is configured to:

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 claim 5, wherein the control device is configured to:

the defrosting heat exchanger exits the defrosting process and enters a common heating operation process, and the defrosting heat exchanger specifically comprises the following steps:

controlling to disconnect a defrost branch communicating refrigerant discharged from the compressor with a liquid side pipe of the outdoor heat exchanger;

controlling to open a liquid pipe throttling device communicated with the outdoor heat exchanger;

and controlling the opening degree of an air pipe throttling device communicated with the defrosting heat exchanger to recover to the opening degree before defrosting.

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

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

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

the outdoor fans respectively correspond to the 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.

9. The air conditioner according to claim 8,

when the outdoor heat exchangers in each outdoor unit module are defrosting, the rotating speed of outdoor fans corresponding to the other outdoor heat exchangers which are not defrosting in the outdoor unit module is increased.

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

the first liquid pipe throttling device is a throttling capillary pipe.

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, the heating operation is stopped during defrosting, and meanwhile, heat is absorbed from the indoor space due to the fact that the indoor heat exchanger is switched to the evaporator, 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 realize continuous heating of the air conditioner and simultaneously perform pressure-controlled defrosting and uniform defrosting on a defrosting heat exchanger, improves defrosting efficiency, ensures the capacity of an indoor unit to be maximized, and improves 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;

at least one outdoor unit module, each outdoor unit module includes:

a compressor;

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

the heat exchanger comprises a plurality of outdoor heat exchangers arranged in parallel, wherein each outdoor heat exchanger comprises a heat exchanger body, a first shunt assembly and a second shunt assembly which are arranged 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 a first liquid pipe throttling device is arranged on a pipeline between the first shunt assembly and the second shunt assembly;

a plurality of second liquid pipe throttling devices which are respectively connected with the indoor unit and the outdoor heat exchangers;

a plurality of air pipe throttling devices which are respectively connected with the flow path switching device and each outdoor heat exchanger;

a defrosting branch circuit which branches a part of the refrigerant discharged from the compressor and allows a part of the refrigerant to flow into the second flow dividing assembly and another part to flow into the first flow dividing assembly through the first pipe-in-pipe throttling means in response to selection of one of the plurality of outdoor heat exchangers;

the control device controls each flow path switching device, each second liquid pipe throttling device, each air pipe throttling device and each defrosting branch when the plurality of outdoor heat exchangers need defrosting, and alternately defrosts each outdoor heat exchanger to be defrosted, so that the outdoor heat exchanger to be defrosted is used as a defrosting heat exchanger to be defrosted and the rest outdoor heat exchangers are used as evaporators to be operated;

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 liquid pipe throttling device communicated with the defrosting heat exchanger; and controlling to open the air pipe throttling device.

Therefore, when the air conditioner performs alternate defrosting, the defrosting pressure of the defrosting heat exchanger can be controlled by controlling the switching device of the flow path to be electrified, controlling the air pipe throttling device and controlling the defrosting branch circuit for communicating the refrigerant discharged by the compressor with the liquid side of the heat exchanger to be defrosted (namely the defrosting heat exchanger), so that the latent heat of the refrigerant is better utilized for defrosting, the defrosting speed is high, the indoor unit keeps certain heating capacity, the air conditioner can continuously heat, and the indoor temperature can quickly rise after defrosting.

In addition, the outdoor heat exchanger can cause that a part of frost formation amount with large wind speed is smaller than a part of frost formation amount with small wind speed due to different wind speeds, a first liquid pipe throttling device is arranged between a first shunt assembly and a second shunt assembly on the liquid side of the outdoor heat exchanger, when the outdoor heat exchanger is defrosted, one part of exhaust of a compressor passing through a defrosting branch circuit directly passes through the second shunt assembly with small wind speed to enter the heat exchanger body for heat exchange, the other part of exhaust of the compressor passes through the first shunt assembly with large wind speed after being throttled by the first liquid pipe throttling device to enter the heat exchanger body for heat exchange, so that the refrigerant amount entering the heat exchanger body corresponding to the first shunt assembly is smaller than the refrigerant amount entering the heat exchanger body corresponding to the second shunt assembly, uniform defrosting of the outdoor heat exchanger is realized, and.

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

controlling and opening the air pipe throttling device, and controlling and adjusting the opening degree of the air pipe throttling device communicated with the air side of the defrosting heat exchanger according to the exhaust superheat degree of the compressor and the target superheat degree range;

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

In this application, the opening of the air pipe throttling device is controlled and opened, and the opening of the air pipe throttling device communicated with the air side of the defrosting heat exchanger is controlled and adjusted according to the exhaust superheat degree and the target superheat degree range of the compressor, specifically:

setting a target exhaust superheat range of the compressor;

calculating the discharge superheat degree of the compressor;

and comparing whether the exhaust superheat degree is within the target exhaust superheat degree range, if so, keeping the amount of the refrigerant passing through the defrosting branch, and if not, adjusting the opening degree of the air pipe throttling device.

In this application, the amount of the refrigerant, which is a part of the refrigerant discharged from the compressor and enters the liquid-side tube of the defrosting heat exchanger, is controlled and adjusted 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 a liquid side pipe of the defrosting heat exchanger.

In this application, adjust trachea throttling arrangement's aperture specifically is:

when the exhaust superheat degree is larger than the upper limit value of the target exhaust superheat degree range, increasing the opening degree of the air pipe throttling device;

and when the exhaust superheat degree is smaller than the lower limit value of the target exhaust superheat degree range, reducing the opening degree of the air pipe throttling device.

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

when the defrosting pressure is larger than the upper limit value of the target defrosting pressure range, reducing the amount of refrigerant of a part of refrigerant discharged by the compressor entering a liquid side pipe of the defrosting heat exchanger;

when the defrosting pressure is less than the lower limit value of the target defrosting pressure range, the amount of the refrigerant of which a part of the refrigerant discharged by the compressor enters a liquid side pipe of the defrosting heat exchanger is increased.

In this application, the control device is configured to:

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 the present application, the control device is configured to:

the defrosting heat exchanger exits the defrosting process and enters a common heating operation process, and the defrosting heat exchanger specifically comprises the following steps:

controlling to disconnect a defrost branch communicating refrigerant discharged from the compressor with a liquid side pipe of the outdoor heat exchanger;

controlling to open a liquid pipe throttling device communicated with the outdoor heat exchanger;

and controlling the opening degree of an air pipe throttling device communicated with the defrosting heat exchanger to recover to the opening degree before defrosting.

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

In this application, the outdoor unit module further includes:

the outdoor fans respectively correspond to the 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 the application, when the outdoor heat exchangers exist in each outdoor unit module and are defrosting, the rotating speed of outdoor fans corresponding to the other outdoor heat exchangers which are not defrosting in the outdoor unit module is increased.

In the present application, the first pipe restriction is a capillary tube.

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 structural view of an outdoor heat exchanger in an embodiment of an air conditioner according to the present invention;

fig. 3 is a flowchart illustrating a defrosting heat exchanger defrosting operation when an embodiment of the air conditioner is in a rotating defrosting mode.

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 5-1 and 5-2 (i.e., the indoor heat exchangers as described above) and indoor fans 6-1 and 6-2, respectively, the indoor fans 6-2 and 6-2 serving to blow cold or hot air generated by the indoor heat exchangers 5-1 and 5-2 toward an indoor space, respectively.

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 comprises at least one outdoor unit module, and all the outdoor unit modules are arranged in parallel.

For example, there are two outdoor unit modules, denoted as outdoor unit modules a and a ', each outdoor unit module a/a' includes a compressor, a flow path switching device, a plurality of outdoor heat exchangers arranged in parallel, a plurality of liquid pipe throttling devices, a plurality of outdoor fans, a defrosting branch, a plurality of gas pipe throttling devices, and a gas-liquid separator.

The outdoor unit modules a and a' have the same structure.

Referring to fig. 1, there is shown a system configuration diagram of an air conditioner, which includes an outdoor unit module including a compressor 1, a flow path switching device 2, two outdoor heat exchangers 11-1 and 11-2 arranged in parallel, two liquid pipe throttling devices 10-1 and 10-2, two outdoor fans 12-1 and 12-2, a defrosting branch, two gas pipe throttling devices 24-1 and 24-2, and a gas-liquid separator 14.

The flow path switching device 2 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 2 is a four-way valve having four terminals C, D, S and E.

When the flow switching device 2 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 5-1 and 5-2 are used as evaporators, the outdoor heat exchangers 11-1 and 11-2 are used as condensers, and the air conditioner refrigerates.

When the four-way valve is electrified and reversed, C is connected with S, D is connected with E, so that the indoor heat exchangers 5-1 and 5-2 are used as condensers, the outdoor heat exchangers 11-1 and 11-2 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 11-1 (11-2), an outdoor fan 12-1 (12-2), a liquid pipe throttling means 10-1 (10-2) connecting a liquid pipe of the indoor heat exchanger 5-1 (5-2) and a liquid pipe of the outdoor heat exchanger 11-1 (11-2), and a gas pipe throttling means 24-1 (24-2) connecting a gas pipe of the outdoor heat exchanger 11-1 (11-2) and a discharge port of the compressor 1.

In the present application, the air pipe throttling device 24-1/24-2 and the liquid pipe throttling device 10-1/1-2 may be electronic expansion valves, two-way thermostatic expansion valves, or the like.

[ Uniform defrosting ]

Referring to fig. 1 and 2, a structure of the outdoor heat exchanger 11-1 will be described as an example.

The outdoor heat exchanger 11-1 includes a heat exchanger body 111, a main air duct 112 communicating with the heat exchanger body 111, first and second branch assemblies communicating with the heat exchanger body 111, a main liquid duct 113 formed by merging a liquid duct L1 connected to the first branch assembly and a liquid duct L2 connected to the second branch assembly.

Wherein the air pipe connecting pipe of the main air pipe 112 is connected with the air pipe throttling device 24-1.

Wherein the first flow-dividing assembly comprises a first flow-dividing capillary tube 111A communicating with the heat exchanger body 111 and a first flow-dividing head 111A' communicating with the first flow-dividing capillary tube 111A.

The second flow dividing assembly includes a second flow dividing capillary tube 111B communicating with the heat exchanger body 111 and a second flow dividing head 111B' communicating with the second flow dividing capillary tube 111B.

Liquid pipe L1 connected to first branch head 111A and liquid pipe L2 connected to second branch head 111B' merge to form main liquid pipe 113.

Generally, when the air conditioner is operated for heating in a normal state, a portion 11-1A of the heat exchanger body 111 connected to the first shunting assembly is located at a wind speed greater than a portion 11-1B of the heat exchanger body 111 connected to the second shunting assembly, and thus, the frosting amount of the portion 11-1A of the outdoor heat exchanger 11-1 is smaller than that of the portion 11-1B of the outdoor heat exchanger 11-1.

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 11-1A entering the outdoor heat exchanger 11-1 is less than the resistance to the portion 11-1B entering the outdoor heat exchanger 11-1.

During defrosting, the frosting amount of the part 11-1A of the outdoor heat exchanger 11-1 is small, the resistance of the corresponding first shunt capillary 111A is small, and the amount of the entering refrigerant is large; the portion 11-1B of the outdoor heat exchanger 11-1 has a large frost formation amount, the resistance of the corresponding second flow-dividing capillary tube 111B is large, and the amount of the refrigerant entering 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 purpose, a first pipe throttling device 23-1 is provided on the line L2 between the second tap 111B' of the outdoor heat exchanger 11-1 and the main liquid pipe 113.

The first pipe throttling device 23-1 is not controlled by the outside, the opening degree is constant, and a throttling capillary with a fixed opening degree can be selected.

The first pipe restriction 23-1 may also select a combination of a restriction capillary and a check valve, or a combination of a restriction capillary and a solenoid valve, etc., wherein the check valve is controlled by the control means.

The first pipe restriction 23-1 may be connected to pipe L2 of the line between the first tap 111A 'and the second tap 111B'.

It may be provided in the liquid pipe L1 of the line, but it is necessary to select the outdoor heat exchanger 11-1 so that a part of the refrigerant discharged from the compressor 1 is branched by the defrosting branch and a part of the refrigerant directly flows into the second branch header 111B 'and the other part of the refrigerant flows into the first branch header 111A' after being throttled by the first pipe throttling device 23-1.

In the present application, the first pipe throttling device 23-1 is connected to the pipe L2 of the pipeline between the first branch header 111A 'and the second branch header 111B' for reducing the amount of refrigerant entering the portion 11-1A of the outdoor heat exchanger 11-1 and increasing the amount of refrigerant entering the portion 11-1B of the outdoor heat exchanger 11-1 to achieve the uniform defrosting of the portion 11-1A and the portion 11-1B of the outdoor heat exchanger 11-1 when the outdoor heat exchanger 11-1 is defrosted (see the following description for details).

After a part of the refrigerant discharged from the compressor 1 is branched, it does not flow into the outdoor heat exchangers 11-1 and 11-2 through the defrost branch, respectively, i.e., it flows into the outdoor heat exchangers 11-1 and 11-2 alternately.

Referring to fig. 1, a defrost branch 25-1 'is provided on a line between the discharge port of the compressor 1 and the second diverging component of the outdoor heat exchanger 11-1, and a defrost branch 25-2' is provided on a line between the discharge port of the compressor 1 and the second diverging component of the outdoor heat exchanger 11-2.

A gas pipe throttling device 25-1 is provided on the defrosting branch 25-1' for allowing a part of refrigerant discharged from the compressor 1 to be throttled to a proper pressure by the gas pipe throttling device 25-1 to enter the outdoor heat exchanger 11-1 for heat exchange defrosting when turned on.

A gas pipe throttling device 25-2 is provided on the defrosting branch 25-2' for allowing part of the refrigerant discharged from the compressor 1 to be throttled to a proper pressure by the throttling device 25-2 to enter the outdoor heat exchanger 11-2 for heat exchange defrosting when being opened.

In order to avoid that the refrigerant flowing through the indoor heat exchangers 5-1 and 5-2 flows into the outdoor heat exchanger 11-1 or 11-2 after heat exchange when the outdoor heat exchanger 11-1 or 11-2 is defrosted without interruption, one ends of the defrosting branch 25-1' and the defrosting branch 25-2' are respectively connected to the exhaust port of the compressor 1, the other end of the defrosting branch 25-1' is connected to the pipeline between the second tap 111B ' of the outdoor heat exchanger 11-1 and the first liquid-tube throttling device 23-1, and the other end of the defrosting branch 25-2' is connected to the pipeline between the second tap of the outdoor heat exchanger 11-2 and the first liquid-tube throttling device 23-2 of the corresponding outdoor heat exchanger 11-2.

The control device is used for controlling the on-off of the flow path switching device 2, the air pipe throttling devices 24-1 and 24-2, the liquid pipe throttling devices 10-1 and 10-2 and the defrosting branches 25-1 'and 25-2' in the outdoor unit module (namely controlling the air pipe throttling devices 25-1 and 25-2).

[ 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 duct throttling devices 24-1 and 24-2 in the outdoor unit module are both opened, the air duct throttling devices 25-1 and 25-2 are both closed, the liquid duct throttling devices 10-1 and 10-2 are both opened, and the outdoor fans 12-1 and 12-2 are both opened.

In some embodiments, the flow switching device 2 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 gas side stop valve 3 and the first extension pipe 4 and enters the indoor heat exchangers 5-1 and 5-2 through D and E.

After heat exchange in the indoor heat exchangers 5-1 and 5-2, condensation heat release is carried out to form liquid refrigerant, and then the refrigerant passes through the indoor machine side throttling devices 7-1 and 7-2, the second extension pipe 8 and the liquid side stop valve 9 and enters the liquid pipe throttling devices 10-1 and 10-2 to be throttled to a low-temperature low-pressure gas-liquid state.

Wherein the refrigerant throttled from the tube throttling device 10-1 is then divided into two, and the refrigerant throttled from the tube throttling device 10-2 is then divided into two.

The outdoor heat exchanger 11-1 will be described as an example.

One path of the heat is transmitted to the outdoor heat exchanger 11-1 through the first liquid pipe throttling device 23-1, the second flow dividing head 111B' and the second flow dividing capillary 111B to be evaporated and absorbed, and then is changed into a gas state.

The other path enters the outdoor heat exchanger 11-1 through the first flow dividing head 111A' and the first flow dividing capillary tube 111A to be evaporated and absorbed, and then becomes gaseous.

The refrigerant coming out of the outdoor heat exchanger 11-1 is throttled by the air pipe throttling device 24-1, 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.

In the normal heating operation mode, the resistance of the part 11-1A of the corresponding outdoor heat exchanger 11-1 is greater than the resistance of the part 11-1B of the corresponding outdoor heat exchanger 11-1, and the wind speed of the part 11-1A of the outdoor heat exchanger 11-1 is greater than the wind speed of the part 11-1B of the outdoor heat exchanger 11-1, so that the uniform heating shunting can be ensured, and the optimal heating can be realized.

Similarly, the refrigerant throttled by the liquid pipe throttling device 10-2 is then divided into two paths of refrigerant, and the flow direction of the refrigerant in the outdoor heat exchanger 4-2 is similar to that of the refrigerant in the outdoor heat exchanger 4-1.

The outdoor fans 12-1 and 12-2 are always on throughout the normal heating operation mode.

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, the air duct throttles 24-1 and 24-2 in the outdoor unit module are both open, the air duct throttles 25-1 and 25-2 are both closed, the liquid duct throttles 10-1 and 10-2 are both open, and the outdoor fans 12-1 and 12-2 are both open.

And the four-way valve 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 is throttled by the D and C through the air pipe throttling devices 24-1 and 24-2 and then enters the outdoor heat exchangers 11-1 and 11-2.

After heat exchange, the outdoor heat exchanger 11-1 is condensed and released heat and then is divided into two paths, and after heat exchange, the outdoor heat exchanger 11-2 is condensed and released heat and then is divided into two paths.

The refrigerant flow direction will be described by taking the outdoor heat exchanger 11-1 as an example.

One of the flows passes through the first flow dividing head 111A ' and the first flow dividing capillary tube 111A, and the other flows passes through the second flow dividing head 111B ', the second flow dividing capillary tube 111B, and the first pipe throttling device 23-1, and then joins the refrigerant flowing out through the first flow dividing head 111A ' and the first flow dividing capillary tube 111A.

The merged refrigerant then passes through the pipe throttling device 10-1, the liquid side stop valve 9 and the second extension pipe 8, enters the indoor heat exchangers 5-1 and 5-2 to be evaporated and absorb heat, and is changed into a gas state.

The refrigerant from the indoor heat exchangers 5-1 and 5-2 passes through the first extension pipe 4, the gas side stop valve 3, and the four-way valve E and S, enters the gas-liquid separator 14, and is finally sucked into the compressor 1 to be compressed, thereby completing the refrigeration cycle.

Similarly, the flow direction of the refrigerant which is condensed and released heat after the heat exchange from the outdoor heat exchanger 11-2 and then divided into two paths in the outdoor heat exchanger 4-2 is similar to the flow direction of the outdoor heat exchanger 4-1.

The outdoor fans 12-1 and 12-2 are always on throughout the normal cooling operation mode.

Reverse defrost mode of operation

When the control device of the air conditioner detects and judges that the outdoor heat exchanger 11-1 and/or 11-2 needs defrosting, the compressor 1 firstly reduces the frequency or directly stops, and the indoor fans 6-1 and 6-2 and the outdoor fans 12-1 and 12-2 stop running.

Then, the four-way valve is powered off and reversed, the compressor 1 is started, the outdoor heat exchangers 11-1 and 11-2 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 11-1 and 11-2.

After defrosting is completed, the compressor 1 is stopped; then, the four-way valve is electrified and reversed, the compressor 1 is restarted, the outdoor fans 12-1 and 12-2 are restarted, the indoor fans 6-1 and 6-2 are operated according to a cold air preventing program, and the air conditioner is restarted to enter a 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.

In the air conditioner with a single outdoor unit module, when a plurality of outdoor heat exchangers in the single outdoor unit module are defrosted, a plurality of outdoor heat exchangers to be defrosted execute a rotation defrosting operation mode.

In an air conditioner having a plurality of outdoor unit modules, a plurality of outdoor heat exchangers perform sequential rotation defrosting (i.e., only one outdoor heat exchanger performs defrosting at a time), a defrosting process is performed according to defrosting conditions, and defrosting is started, for example, in a preset order, and a control device performs control of the defrosting heat exchanger (i.e., the outdoor heat exchanger that is performing defrosting) and the remaining outdoor heat exchangers in the defrosting process.

In the air conditioner with a plurality of outdoor unit modules, when a plurality of outdoor heat exchangers in the outdoor unit modules are combined and rotated for defrosting (namely, one outdoor heat exchanger in each outdoor unit module is selected to form a plurality of outdoor heat exchange combinations for defrosting at the same time, but two outdoor heat exchangers belonging to the same outdoor unit module are not defrosted at the same time), a defrosting process is started according to defrosting conditions, defrosting is started according to a preset combination sequence for example, and in the defrosting process, a control device executes control over the defrosting heat exchanger and the rest of the outdoor heat exchangers.

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 the above-described various defrosting processes, if there is a defrosting heat exchanger in the outdoor unit module, the control of the devices related to the defrosting heat exchanger in the outdoor unit module where the defrosting heat exchanger is located is the same, and the remaining devices in the outdoor unit module are maintained in the same state as in the normal heating operation mode.

In some embodiments, referring to fig. 1, only the alternate defrosting of the outdoor heat exchangers 11-1 and 11-2 in a single outdoor unit module will be described.

S1: the process begins.

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

S3: and judging whether the outdoor heat exchangers 11-1 and 11-2 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 11-1 and 11-2 may be alternately defrosted according to the amount of frosting of the outdoor heat exchangers 11-1 and 11-2 to be defrosted (i.e., defrosting heat exchangers).

The outdoor heat exchangers 11-1 and 11-2 can be sequentially defrosted according to the sequence of the frost formation amount from large to small.

The determination of the frosting amount may be performed by detecting an index indicative of the frosting amount by a detecting means (not shown), such as at least one of the heating capacity of the outdoor heat exchangers 11-1 and 11-2, 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 11-2 and 11-2 according to the change 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.

Assuming that the frosting amount of the outdoor heat exchanger 11-1 is greater than that of the outdoor heat exchanger 11-2, the outdoor heat exchanger 11-1 should be defrosted first to avoid that the normal operation of the outdoor heat exchanger 11-1 is affected by excessive frosting. The outdoor heat exchanger 11-2 is in a normal heating operation mode at this time.

That is, the outdoor heat exchanger 11-1 is performed as a defrosting heat exchanger, and the outdoor heat exchanger 11-2 is performed as an evaporator.

After the defrosting of the outdoor heat exchanger 11-1 is completed and the normal heating operation mode is entered, the outdoor heat exchanger 11-2 is defrosted.

That is, the switching of the outdoor heat exchanger 11-2 is performed as a defrosting heat exchanger, and the outdoor heat exchanger 11-1 is performed as an evaporator.

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

S41: and controlling the switching device 2 to be powered on, controlling the defrosting branch to enable one part of refrigerant discharged by the compressor 1 to pass through the second shunting assembly of the defrosting heat exchanger, controlling the other part of refrigerant to flow into the first shunting assembly of the defrosting heat exchanger through the first liquid pipe throttling device, cutting off the liquid pipe throttling device communicated with the defrosting heat exchanger, controlling the air pipe throttling device to be opened, and controlling the rest outdoor heat exchanger to be executed as an evaporator.

The outdoor heat exchanger 11-1 in the outdoor unit module is used as a defrosting heat exchanger to perform a defrosting process, and the outdoor heat exchanger 11-2 is used as an evaporator to perform a normal heating operation process.

And keeping the four-way valve in an electrified and opened state, controlling an air pipe throttling device 25-1 on the defrosting branch 25-1' to be opened, closing the outdoor fan 12-1, closing the liquid pipe throttling device 10-1, and keeping the rest devices in the same state as the normal heating operation mode.

Referring to fig. 1, a dotted arrow indicates a refrigerant flow direction in the defrosting process of the outdoor heat exchanger 11-1.

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.

Part of the high-temperature and high-pressure refrigerant enters the indoor heat exchangers 5-1 and 5-2 through the D and E, the gas side stop valve 3 and the first extension pipe 4, and is condensed and released heat after heat exchange in the indoor heat exchangers 5-1 and 5-2 to become liquid refrigerant.

Then the refrigerant passes through indoor machine side throttling devices 7-1 and 7-2, a second extension pipe 8 and a liquid side stop valve 9, enters a liquid pipe throttling device 10-2, is throttled to a low-temperature low-pressure gas-liquid two state, and then is divided into two paths.

One path of the heat is transmitted into the outdoor heat exchanger 11-2 through the first liquid pipe throttling device 23-2, the second flow dividing head of the outdoor heat exchanger 11-2 and the second flow dividing capillary tube to be evaporated and absorbed, and then the heat is changed into a gas state.

The other path of the gas enters the outdoor heat exchanger 11-1 through a first flow dividing head and a first flow dividing capillary tube of the outdoor heat exchanger 11-2 to be evaporated and absorbed, and then the gas is changed into a gas state.

The refrigerant coming out of the outdoor heat exchanger 11-2 flows out after being throttled by the air pipe throttling device 24-2.

The other part of the high-temperature and high-pressure refrigerant is throttled to a proper pressure by the air pipe throttling device 25-1 on the defrosting branch 25-1', and then is divided into two paths.

One branch enters a second branch head 111B' and a second branch capillary tube 111B of the outdoor heat exchanger 11-1 to enter the heat exchanger body 111 for heat exchange and defrosting.

The other branch flow passes through the first pipe throttling device 23-1, the first branch head 111A' of the outdoor heat exchanger 11-1 and the first branch capillary tube 111A and enters the heat exchanger body 111 for heat exchange and defrosting.

Then enters the air pipe throttling device 24-1 through the main air pipe 112 of the outdoor heat exchanger 11-1, joins with the refrigerant flowing out after being throttled by the air pipe throttling device 24-2, passes through C and S of the four-way valve, enters the gas-liquid separator 14, and is finally sucked into the compressor 1 for compression.

Since the portion 11-1A of the heat exchanger body 111 connected to the first tap 111A 'is located at a wind speed higher than that of the portion 11-1B of the heat exchanger body 111 connected to the second tap 111B', the amount of frost formed on the portion 11-1A of the heat exchanger body 111 is smaller than that on the portion 11-1B under a low-temperature and high-humidity environment.

During defrosting, the first liquid pipe throttling device 23-1 and the first shunting capillary tube 111A are connected in series, so that the capillary resistance of the part 11-1A entering the heat exchanger body 111 is increased, the refrigerant flow in the part 11-1B of the outdoor heat exchanger 11-1 is relatively reduced, uniform defrosting of the parts 11-1A and 11-1B of the outdoor heat exchanger 11-1 is realized, the integral defrosting speed is increased, the defrosting power consumption is reduced, and the energy consumption is saved.

Generally, the outdoor fan 12-1 is disposed above the outdoor heat exchanger 11-1, and thus, a portion 11-1A of the outdoor heat exchanger 11-1 is an upper portion of the outdoor heat exchanger 11-1, and a portion 11-1B of the outdoor heat exchanger 11-1 is a lower portion of the outdoor heat exchanger 11-1.

In the application, the opening degree of the air pipe throttling device 24-1 is controlled and adjusted according to the exhaust superheat degree of the compressor 1 and a target exhaust superheat degree range, so that the exhaust superheat degree of the compressor 1 tends to be maintained within the target exhaust superheat degree range, wherein the exhaust superheat degree indirectly controls the outlet temperature of the heat exchanger (detected by a temperature sensor 104 a); according to the defrosting pressure and the target defrosting pressure range, the opening degree of the air pipe throttling device 25-1 is controlled and adjusted, the defrosting pressure of the outdoor heat exchanger 11-1 tends to be maintained in the target defrosting pressure range, the defrosting pressure is guaranteed, the outlet of the defrosting heat exchanger is controlled to be in a two-phase state or a liquid state by utilizing latent heat for defrosting, the defrosting time is shortened, the defrosting speed and efficiency are improved, the exhaust superheat degree is guaranteed, the capacity of an indoor unit is maximized, and the indoor thermal comfort is maintained.

In defrosting the outdoor heat exchanger 11-1, how to control the opening degree of the air pipe throttling device 24-1 and the opening degree of the air pipe throttling device 25-1 is described in detail with reference to fig. 3.

Before entering the defrosting process, the initial opening degree of the air pipe throttling device 24-1 and the air pipe throttling device 25-1 needs to be set, for example, the initial opening degree of the air pipe throttling device 24-1 can be set to be the opening degree before defrosting (for example, full opening); since the air pipe throttling device 25-1 is turned off before defrosting, it is necessary to set an initial opening degree (e.g., full opening) of the air pipe throttling device 25-1 at the time of defrosting before defrosting.

S1': a target discharge superheat range of the compressor 1 and a target defrost pressure range are set.

In the present application, there is a range of target exhaust superheat Tdsho, for example, 10 ℃. ltoreq. Tdsho. ltoreq.40 ℃.

A target exhaust superheat range (Tdsho-. lambda., Tdsho + lambda.) is set based on the target exhaust superheat Tdsho, for example, 2. degreeClambda. ≦ 5 ℃.

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 target defrosting pressure Pfo can be obtained 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': the discharge superheat Tdsh of the compressor 1 is calculated.

The discharge superheat Tdsh of the compressor 1 is calculated from the discharge pressure Pd (detected by the pressure sensor 101) and the discharge temperature Td.

The exhaust superheat Tdsh is equal to the difference between the exhaust temperature Td and a saturation temperature Tec corresponding to the exhaust pressure Pd, which saturation temperature Tec is found from the exhaust pressure query.

S3': comparing whether the exhaust superheat degree Tdsh is within a target exhaust superheat degree range;

s31': if the exhaust superheat degree Tdsh is within the target exhaust superheat degree range, keeping the opening degree of the air pipe throttling device 24-1, and executing to S4'; if not, the opening degree of the air pipe throttling device 24-1 is adjusted, and the process goes to S4'.

The process of specifically adjusting the opening degree of the tracheal throttle device 24-1 is described below.

S32': if the exhaust superheat Tdsh is greater than the upper limit value of the target exhaust superheat range, the opening degree of the air pipe throttling device 24-1 is increased by one adjustment step number, and the process is executed to S4'.

That is, the next opening degree EV24-1(n +1) = EV24-1(n) + Δ EV24-1 of the tracheal throttle device 24-1, where Δ EV24-1 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 exhaust superheat Tdsh is less than the lower limit value of the target exhaust superheat range, the opening degree of the air pipe throttling device 24-1 is decreased by one adjustment step number, and the process is executed to S4'.

That is, the next opening EV24-1(n +1) = EV24-1(n) - Δ EV24-1 of the tracheal throttle device 24-1, where Δ EV24-1 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.

S4': comparing whether the defrost pressure Pf is within the target defrost pressure range, if yes, maintaining an amount of refrigerant of a portion of the refrigerant discharged from the compressor 1 to be introduced into the liquid side tube of the defrost heat exchanger 1-1, i.e., maintaining an amount of refrigerant passing through the defrost branch 25-1', and proceeding to S42, if no, adjusting an amount of refrigerant of a portion of the refrigerant discharged from the compressor 1 to be introduced into the liquid side tube of the defrost heat exchanger 1-1, i.e., adjusting an amount of refrigerant passing through the defrost branch 25-1', and proceeding to S42.

The amount of refrigerant passing through the defrost branch 25-1 'is adjusted by controlling the opening of the gas line throttling device 25-1 on the defrost branch 25-1', as follows.

S41': if the defrosting pressure Pf is within the target defrosting pressure range, the opening degree of the air pipe throttling device 25-1 is maintained, and execution proceeds to S42.

S42': if the defrosting pressure Pf is greater than the upper limit value of the target defrosting pressure range, the opening degree of the air pipe throttling device 25-1 is decreased by one adjustment step number, and execution goes to S42.

That is, the next opening EV25-1(n +1) = EV25-1(n) - Δ EV25-1 of the tracheal throttle device 25-1, where Δ EV25-1 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.

S43': if the defrosting pressure Pf is less than the lower limit value of the target defrosting pressure range, the opening degree of the air pipe throttling device 25-1 is increased by one adjustment step number, and execution goes to S42.

That is, the next opening degree EV25-1(n +1) = EV25-1(n) + Δ EV25-1 of the tracheal throttle device 25-1, where Δ EV25-1 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 air pipe throttling device 24-1 and the air pipe throttling device 25-1 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 11-1 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 11-1 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 for adjusting the opening degrees of the tracheal throttle device 24-1 and the tracheal throttle device 25-1, 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'.

After the defrosting of the outdoor heat exchanger 11-1 is finished, the defrosting process is exited, and then the normal heating operation process is entered.

The outdoor heat exchanger 11-1 exits the defrosting process and enters a normal heating operation process, which specifically comprises the following steps:

(1) controlling the air pipe throttling device 25-1 on the defrosting branch 25-1' to be closed;

(2) turning on the outdoor fan 12-1; and

(3) opening the pipe throttling means 10-1;

(4) the opening degree of the air pipe throttling device 24-1 is controlled to return to the opening degree before defrosting, namely, the opening degree of the air pipe throttling device 24-1 is fully opened in normal heating operation.

In the defrosting process, the indoor side throttling devices 7-1 and 7-2 are controlled before defrosting, the liquid pipe throttling device 10-2 is controlled to be in normal heating control, namely, the outlet superheat degree Ts2 of the outdoor heat exchanger 11-2 is controlled, namely, the temperature sensor 104b detects the outlet temperature T, the pressure sensor 103b detects the outlet pressure P, the outlet superheat degree Ts2 of the outdoor heat exchanger 11-2 is the difference between the outlet temperature T and the saturation temperature corresponding to the outlet pressure P, and the outlet superheat degree Ts2 is controlled within 0-2 ℃.

Similarly, in order to ensure that the outlet superheat degree of the outdoor heat exchanger 11-1 is controlled when the outdoor heat exchanger 11-1 enters a normal heating operation process after defrosting is finished and the defrosting process is exited, for example, the outdoor fan 12-1 and the liquid pipe throttling device 10-1 are opened, the air pipe throttling device 25-1 is closed, the air pipe throttling device 24-1 is restored to the opening degree before defrosting, and the opening degree of the liquid pipe throttling device 10-1 is controlled so that the outlet superheat degree of the outdoor heat exchanger 11-1 is within 0-2 ℃.

Thereafter, the outdoor heat exchanger 11-2 serves as a defrosting heat exchanger to enter a defrosting process, and the outdoor heat exchanger 11-1 serves as an evaporator to maintain a general heating operation process.

And keeping the four-way valve powered on, controlling the air pipe throttling device 25-2 on the defrosting branch 25-2' to be opened, closing the outdoor fan 12-2, closing the liquid pipe throttling device 10-2, and keeping the rest devices in the same state as the state in the normal heating operation mode.

The defrosting process of the outdoor heat exchanger 11-2 is referred to as the defrosting process of the outdoor heat exchanger 11-1.

When the outdoor heat exchanger 11-2 is defrosted, the outdoor heat exchanger 11-1 performs a general heating operation process.

In the air conditioner having a single outdoor unit module, after the outdoor heat exchangers 11-1 and 11-2 are alternately defrosted a plurality of times, a reverse defrosting operation mode may be performed to completely defrost the outdoor heat exchangers 11-1 and 11-2. Of course, the reverse defrost mode of operation may be selected under other conditions.

[ separation wind field ]

Since the corresponding outdoor fan 12-2 of the outdoor heat exchanger 11-2 is kept in operation when the outdoor heat exchanger 11-1 is defrosted, in order to avoid the situation that the outdoor heat exchanger 11-1 cannot be defrosted effectively due to the wind field generated by the outdoor fan 12-2 blowing through the outdoor heat exchanger 11-1, a separating device (not shown, see the patent document with the application number of 202010279447.2 entitled "outdoor unit of air conditioner") is provided in the present application for separating the wind field.

In the present application, the outdoor fans 12-1 and 12-2 are independently controlled by the control device, respectively, and the outdoor heat exchanger 11-1 and the outdoor fan 12-1 form a first wind field, and the outdoor heat exchanger 11-2 and the outdoor fan 12-1 form a second wind field, and the partition device serves to separate the first wind field and the second wind field.

That is, it does not blow wind to the outdoor heat exchanger 11-2 when the outdoor fan 12-1 is operated and the outdoor fan 12-2 is not operated, and it does not blow wind to the outdoor heat exchanger 11-1 when the outdoor fan 12-2 is operated and the outdoor fan 12-1 is not operated.

Thus, when the outdoor heat exchanger 11-1 performs defrosting, since the partition device separates the first wind field and the second wind field, the first wind field is not affected even if the outdoor fan 12-2 is still operated.

Therefore, the situation that when the outdoor heat exchanger 11-1 is defrosted, the surface of the outdoor heat exchanger is blown by wind is effectively avoided, the situation that the outdoor temperature is low, the defrosting cannot be effectively carried out due to overlarge condensation load is further prevented, and uninterrupted heating of a full-temperature area can be realized.

In addition, when the outdoor fan 12-1 stops running (i.e. the outdoor heat exchanger 11-1 is defrosting), the rotating speed of the outdoor fan 12-2 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.

And when the outdoor heat exchanger 11-1 exits the defrosting process and enters the normal heating operation process, the outdoor fan 12-1 is turned on correspondingly and the outdoor fan 12-2 of the outdoor heat exchanger 11-2 is turned off.

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.