CN112444001A

CN112444001A - Air conditioner

Info

Publication number: CN112444001A
Application number: CN202011371832.6A
Authority: CN
Inventors: 张恒; 董辰; 孟建军; 夏兴祥
Original assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Current assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Priority date: 2020-11-30
Filing date: 2020-11-30
Publication date: 2021-03-05
Also published as: WO2022110771A1

Abstract

The invention discloses an air conditioner, comprising: at least one indoor set, a plurality of off-premises station modules, each off-premises station module includes: a compressor; a defrost throttling device; the air side valve is connected with the defrosting throttling device in parallel; two outdoor heat exchangers arranged in parallel; the two defrosting switching devices respectively correspond to one outdoor heat exchanger and are used for switching the outdoor heat exchanger to be communicated with the defrosting throttling device or the gas-liquid separator; two liquid pipe throttling devices; one end of the throttling device is connected with the position where one liquid pipe throttling device is connected with the liquid side of the corresponding outdoor heat exchanger, and the other end of the throttling device is connected with the position where the other liquid pipe throttling device is connected with the corresponding outdoor heat exchanger; the control device controls each outdoor heat exchanger to be defrosted to sequentially rotate for defrosting or one outdoor heat exchanger to be defrosted in each of the outdoor unit modules to be combined and rotated for defrosting. The invention realizes the alternate defrosting of the defrosting heat exchangers, realizes the indoor uninterrupted heating and improves the indoor thermal comfort.

Description

Air conditioner

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 pressure-controlled defrosting of a defrosting heat exchanger at the same time, improve defrosting efficiency, ensure the maximization of indoor unit capacity and improve 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;

a plurality of outdoor unit modules, each outdoor unit module comprising:

a compressor;

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

a defrost throttle for throttling a portion of refrigerant from the compressor;

an air side valve connected in parallel with the defrost throttling device;

two outdoor heat exchangers arranged in parallel;

the two defrosting switching devices respectively correspond to one outdoor heat exchanger and are used for switching the outdoor heat exchanger to be communicated with the defrosting throttling device or communicated with the gas-liquid separator;

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

one end of the throttling device is connected with the position where one liquid pipe throttling device is connected with the liquid side of the corresponding outdoor heat exchanger, and the other end of the throttling device is connected with the position where the other liquid pipe throttling device is connected with the corresponding outdoor heat exchanger;

a control device for controlling the flow path switching device, each of the defrosting throttle devices, the air side valve, each of the defrosting switching devices, each of the liquid pipe throttle devices, and the throttle device in each of the outdoor unit modules;

when the outdoor heat exchangers need defrosting, the control device controls the outdoor heat exchangers to be defrosted to sequentially rotate for defrosting or one outdoor heat exchanger combination to be defrosted in each outdoor unit module to be combined and rotated for defrosting, so that the outdoor heat exchangers to be defrosted are used as defrosting heat exchangers to be executed, and the rest outdoor heat exchangers are used as evaporators to be executed;

when the defrosting is performed by turns, the control device controls the flow path switching device in the outdoor unit module where each defrosting heat exchanger is positioned to be powered on; controlling to open the defrosting throttling device; controlling the defrosting switching device to enable the refrigerant flowing out of the defrosting throttling device to be communicated with a main air pipe of the defrosting heat exchanger; controlling to close a liquid pipe throttling device and a gas side valve which are communicated with the defrosting heat exchanger; controlling to open the throttling device.

The application relates to an air conditioner, when the air conditioner with a plurality of outdoor unit modules is defrosted, a control device controls a flow path switching device to be electrified, a liquid pipe throttling device and an air side valve are controlled to be closed, a defrosting throttling device is controlled to be opened, the defrosting switching device is controlled to enable refrigerant flowing out of the flow throttling device to be communicated with a main air pipe of a defrosting heat exchanger, the throttling device is controlled to be opened, and combined with a defrosting selection mode (the outdoor heat exchanger to be defrosted is selected to be sequentially and alternately defrosted one by one at a time or one outdoor heat exchanger to be defrosted in each of the outdoor unit modules is selected to be combined and alternately defrosted), the rest outdoor heat exchangers can form a heating cycle with an indoor unit when the outdoor heat exchanger to be defrosted is defrosted, thereby realizing uninterrupted heating while defrosting, utilizing latent heat of refrigerant to defrost, the thermal comfort of the user is met, and the indoor temperature rising speed after defrosting is high.

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

controlling and opening a throttling device in an outdoor unit module where the defrosting heat exchanger is located, 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 to open the defrosting throttle device, and controlling and adjusting the opening of the defrosting throttle device 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 a target outlet supercooling degree range of the defrosting heat exchanger;

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;

the throttling device and the defrosting throttling device are the throttling device and the defrosting throttling device in the outdoor unit module where the defrosting heat exchanger is located.

In this application, control is opened defrost throttling arrangement, according to defrosting pressure and target defrosting pressure scope, control defrost throttling arrangement's aperture specifically is:

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 opening degree of the defrosting throttle device, and if not, adjusting the opening degree of the defrosting throttle device.

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, adjust defroster's aperture specifically is:

when the defrosting pressure is larger than the upper limit value of the target defrosting pressure range, reducing the opening degree of the defrosting throttle device;

and when the defrosting pressure is smaller than the lower limit value of the target defrosting pressure range, increasing the opening degree of the defrosting throttle device.

In this application, the control device is configured to:

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

When a plurality of defrosting heat exchangers perform sequential rotation defrosting, 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 period of time, the defrosting heat exchanger exits the defrosting process and enters a normal heating operation process;

when a plurality of defrosting heat exchangers are combined for defrosting by turns, if the outlet temperature of each of all the defrosting heat exchangers which simultaneously defrost is greater than or equal to a first temperature preset value and is maintained for a certain period of time, the defrosting heat exchanger which simultaneously defrosts 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 normal heating operation process, and at least comprises the following steps:

controlling the defrosting switching device to enable the gas side of the defrosting heat exchanger to be communicated with the gas-liquid separator;

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

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

In this application, the air conditioner further includes:

a plurality of first switching valves connected in parallel, each corresponding to one indoor unit, for branching at least a part of the refrigerant from the corresponding compressor switched by the flow switching device of each outdoor unit module, and flowing into a gas side of an indoor heat exchanger in the indoor unit;

the second switching valves are connected in parallel and respectively correspond to one indoor unit, one end of each second switching valve is connected to the position where the first switching valve is connected with the air side of the indoor heat exchanger, and the other end of each second switching valve is connected with the gas-liquid separator of each outdoor unit module;

each of the first switching valve and the second switching valve is controlled by the control device.

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 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.

In the application, when one outdoor heat exchanger in each 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.

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 flowchart illustrating defrosting by a defrosting heat exchanger in an outdoor unit module according to an embodiment of the air conditioner of the present invention;

fig. 3 is a system configuration diagram of 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 comprises at least two outdoor unit modules, and the outdoor unit modules are arranged in parallel.

For example, referring to fig. 1, two parallel outdoor unit modules W1 and W2 are shown.

The outdoor unit module W1/W2 respectively comprises a compressor, a flow path switching device, a defrosting throttle device, a gas side valve, two outdoor heat exchangers arranged in parallel, two defrosting switching devices corresponding to the two outdoor heat exchangers, two liquid pipe throttle devices, two outdoor fans, a throttle device and a gas-liquid separator.

The outdoor unit module W1 and the outdoor unit module W2 have the same structure. And each outdoor unit module W1/W2 includes two parallel outdoor heat exchangers.

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

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

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

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 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.

In the outdoor unit module W1, the defrosting switching device 21/20 is a four-way valve having four terminals C, D, S and E, and is connected to C and D and S and E by default when power is off, and is connected to C and S and D and E when power is on and off.

Referring to fig. 1, when the refrigerant discharged from the compressor 1 flows out through the check valve 2 and enters the outdoor side after being switched by the flow switching device 3, the refrigerant first passes through the defroster 19 and/or the gas side valve 18 connected in parallel to the defroster 19.

The refrigerant throttled by the defrosting throttle device 19 is selectively introduced into the outdoor heat exchanger 4-1 or 4-2 by the state of the defrosting switch device 21/20 corresponding to the outdoor heat exchanger 4-1/4-2, i.e., the refrigerant is alternately introduced into the outdoor heat exchangers 4-1 and 4-2.

Part of the refrigerant discharged from the compressor 1 can be throttled to a suitable pressure by the defrosting throttle device 19 and enter the outdoor heat exchanger 4-1 through the defrosting switching device 21 to be subjected to heat exchange defrosting.

Part of the refrigerant discharged from the compressor 1 can be throttled to a suitable pressure by the defrosting throttle device 19 and enter the outdoor heat exchanger 4-2 through the defrosting switching device 20 to be subjected to heat exchange defrosting.

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

Similarly, the outdoor unit module W2 and the outdoor unit module W1 have the same structure, and the control device is also used to control the flow path switching device, the defrost throttle device 19', the air side valve, the defrost switching device, the pipe throttle device, and the throttle device 28' in the outdoor unit module W2, so that at most one outdoor heat exchanger in the outdoor unit module W2 is defrosted at the same time.

In the present application, the gas-side valve 18 is a controllable valve such as a solenoid valve or a large-diameter two-way valve (for example, a reversible two-way valve with extremely small resistance), and does not have a throttling function.

In the present application, the defrost orifice 19, the tube orifice 6-1/6-2, and the orifice 28 may be electronic expansion valves, two-way thermostatic expansion valves, or the like.

In the present application, if there are two outdoor unit modules W1 and W2 as shown in fig. 1, defrosting the defrosting heat exchanger may include the following three cases.

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

after any one of the outdoor heat exchangers 4-1 and 4-2 in the outdoor unit module W1 is used as a defrosting heat exchanger for defrosting, any one of the outdoor heat exchangers which is not defrosted is selected for defrosting, and the rest outdoor heat exchangers are used as evaporators;

until all outdoor heat exchangers finish defrosting;

in this case, the outdoor heat exchangers to be defrosted are sequentially and alternately defrosted;

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

after any one of the outdoor heat exchangers 4-1 'and 4-2' in the outdoor unit module W1 is used as a defrosting heat exchanger for defrosting, any one of the outdoor heat exchangers which is not defrosted is selected for defrosting, and the rest outdoor heat exchangers are used as evaporators;

until all outdoor heat exchangers finish defrosting;

(3) meanwhile, the combination defrosting of the outdoor heat exchanger 4-1 at the left side in the outdoor unit module W1 and the outdoor heat exchanger 4-1 'at the left side in the outdoor unit module W2 is selected, and the outdoor heat exchanger 4-2 at the right side of the outdoor unit module W1 and the outdoor heat exchanger 4-2' at the right side of the outdoor unit module W2 are used as evaporators;

after the outdoor heat exchanger 4-1 and the outdoor heat exchanger 4-1' are combined for defrosting, the outdoor heat exchanger 4-2 and the outdoor heat exchanger 4-2' are selected for combined defrosting, and the outdoor heat exchanger 4-1' are used as evaporators;

until all outdoor heat exchangers finish defrosting;

in this case, the combination of the outdoor heat exchangers to be defrosted rotates to defrost;

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

The combination is by turns the defrosting for when guaranteeing that indoor constantly heats, promote defrosting efficiency.

As for whether the air conditioner selects sequential rotation defrosting or combined rotation defrosting, the air conditioner needs to be set in advance at the beginning of operation.

Referring to fig. 3, for the three-pipe heat recovery multi-split air conditioner, there are divided into a main cooling mode (i.e., the indoor unit has both cooling and heating states, and the cooling load is greater than the heating load, when the outdoor heat exchanger is used as a condenser) and a main heating mode (i.e., the indoor unit has both cooling and heating states, and the heating load is greater than the cooling load, when the outdoor heat exchanger is used as an evaporator).

In both the two-pipe refrigerant multi-split air conditioner and the three-pipe refrigerant heat recovery multi-split air conditioner (the operation of which will be described in detail below), there is no difference in controlling the respective devices in the outdoor unit modules W1 and W2 when defrosting the outdoor heat exchangers 4-1 or 4-2 in the outdoor unit module W1, the outdoor heat exchangers 4-1 'or 4-2' in the outdoor unit module W2, or the same left-side outdoor heat exchangers 4-1 and 4-1 'in the outdoor unit modules W1 and W2 as well as the right-side outdoor heat exchangers 4-2 and 4-2' in the outdoor unit modules W1 and W2.

[ operation mode of air conditioner ]

Referring to fig. 1, the air conditioner has a normal heating operation mode, a normal cooling operation mode, a reverse 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.

Since the outdoor unit modules W1 and W2 have the same control method and the same refrigerant flow direction during normal heating operation, only the normal heating operation mode of the air conditioner having the outdoor unit module W1 and at least one indoor unit will be described for convenience of description.

Referring to fig. 1, in some embodiments, when the air conditioner is in the normal heating operation mode, the defrost orifice 19 in the outdoor unit module W1 may be opened (preferably closed), the air side valve 18 may be closed or opened (preferably opened), the defrost switch 21 and 20 are powered on, the liquid pipe orifices 6-1 and 6-2 are opened, the outdoor fans 5-1 and 5-2 are opened, and the orifice 28 may be opened (preferably closed).

Wherein the defrost switch 21 and 20 are powered up with D and E in communication and C and S in communication.

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, the D and E of the flow switching device 3, and the first extension pipe 12 to enter 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, then the refrigerant passes through the indoor machine side throttling devices 10-1 and 10-2, the second extension piping 9 and the liquid side stop valve 8, enters the liquid pipe throttling devices 6-1 and 6-2 to be throttled to a low-temperature low-pressure gas-liquid two-state, and the two-phase refrigerant enters the outdoor heat exchangers 4-1 and 4-2 to be evaporated and absorbed heat and then becomes gaseous state.

The refrigerants coming out of the outdoor heat exchangers 4-1 and 4-2 pass through the defrosting switching devices 21 and 20, C and S enter the gas-liquid separator 14, and are finally sucked into the compressor 1 to be compressed, so that the heating cycle is completed.

The outdoor fans 5-1 and 5-2 are always turned 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 the normal cooling operation of the outdoor unit modules W1 and W2, the control method and the refrigerant flow direction of the components are the same, and therefore, for convenience of description, only the normal cooling operation mode of the air conditioner having the outdoor unit module W1 and at least one indoor unit will be described.

Referring to fig. 1, in some embodiments, when the air conditioner is in the normal cooling operation mode, the defrost throttle 19 in the outdoor unit module W1 is opened arbitrarily (preferably opened), the air side valve 18 is opened, the defrost switch 21 and 20 are both de-energized, the pipe throttles 6-1 and 6-2 are both opened, the outdoor fans 5-1 and 5-2 are both opened, and the throttle 28 is opened arbitrarily (preferably closed).

Wherein D and C are communicated and E and S are communicated when the defrosting switching devices 21 and 20 are powered off.

The flow switching device 3 is turned off, the default states are D and C are communicated, and E and S are communicated, the compressor 1 compresses the low-temperature and low-pressure refrigerant into a high-temperature and high-pressure state, passes through the check valve 2 and the gas-side valve 18 (since the defrosting throttle device 19 and the gas-side valve 18 are connected in parallel, the refrigerant flows through the gas-side valve 18 as long as the gas-side valve 18 is opened regardless of whether the defrosting throttle device 19 is opened or not), and then enters the D and C of the defrosting switching devices 21 and 20 to enter the outdoor heat exchangers 4-1 and 4-2.

After heat exchange in the outdoor heat exchangers 4-1 and 4-2, the refrigerant is condensed to release heat and becomes liquid refrigerant, and then the refrigerant enters the indoor side through the liquid pipe throttling devices 6-1 and 6-2.

The refrigerant entering the indoor side is throttled by the throttling devices 10-1 and 10-2, 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 the E and S of the flow path switching device 3, and is finally sucked into the compressor 1 to be compressed, so that the refrigeration cycle is completed.

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

The refrigerant flow direction in the normal cooling operation mode of the air conditioner having the outdoor unit modules W1 and W2 is indicated by the dotted arrows in fig. 1.

The outdoor fans 5-1 and 5-2 are always turned 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 4-1 and/or 4-2 and/or 4-1 'and/or 4-2' needs defrosting, the compressor 1 firstly reduces the frequency or directly stops, and the outdoor fans 5-1 and 5-2 in the indoor fan and outdoor unit module W1 and the outdoor fan in the outdoor unit module W2 stop running.

The air conditioner is operated in a normal cooling operation mode, all the outdoor heat exchangers 4-1, 4-2, 4-1 'and 4-2' are used as condensers to start defrosting, namely heating of all indoor units is stopped and defrosting is carried out on all the outdoor heat exchangers.

After the defrosting is completed, the air conditioner re-enters 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 there are a plurality of outdoor heat exchangers in the outdoor unit modules W1 and W2 for defrosting, the plurality of outdoor heat exchangers to be defrosted perform sequential rotation defrosting or combined rotation defrosting.

When the outdoor heat exchangers 4-1, 4-2, 4-1 'and 4-2' are sequentially rotated for defrosting, a defrosting process is performed according to defrosting conditions, and defrosting is started, for example, according to a preset sequence, and in the defrosting process, the 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.

When the outdoor heat exchangers 4-1, 4-2, 4-1 'and 4-2' are combined and rotated for defrosting, a defrosting process is started according to defrosting conditions, and defrosting is started according to a preset combination sequence, for example, 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 the above two 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 rest of the devices in the outdoor unit module are kept in the same state as in the normal heating operation mode.

Specifically, for example, if there is a defrosting heat exchanger in the outdoor unit module, the opening degree of the defrosting throttle device 19 (19 ') and the opening degree of the throttle device 28 (28 ') are controlled in the same manner in the outdoor unit module W1 (W2) in which the defrosting heat exchanger 4-1 (4-1 ') is located during defrosting.

That is, the outdoor heat exchanger 4-1 is defrosted in the outdoor unit module W1, including two cases.

In the first case: the remaining outdoor heat exchangers 4-2, and the outdoor heat exchangers 4-1 'and 4-2' in the outdoor unit module W2 function as evaporators.

In the second case: the combination of the outdoor heat exchanger 4-1 in the outdoor unit module W1 and the outdoor heat exchanger 4-1 'in the outdoor unit module W2 simultaneously defrosts the air, and the remaining outdoor heat exchanger 4-2 and the outdoor heat exchanger 4-2' in the outdoor unit module W2 serve as evaporators.

The control of the opening degree of the defroster 19 and the opening degree of the throttle device 28 in the outdoor heat exchanger W1 is the same as the control of the opening degree of the defroster 19 'and the opening degree of the throttle device 28' in the outdoor heat exchanger W2.

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

S1: the method comprises the steps of controlling the power on of a flow path switching device 3 in an outdoor unit module where a defrosting heat exchanger is located, controlling a defrosting throttle device 19, an air side valve 18 and a defrosting switching device 21/20 to enable part of refrigerant discharged by a compressor 1 to enter the defrosting heat exchanger through the defrosting throttle device 19 and the defrosting switching device 21/20, closing a liquid pipe throttle device communicated with the defrosting heat exchanger, controlling the throttle device to be opened, and enabling the rest outdoor heat exchanger to be executed as an evaporator.

And (4) taking the outdoor heat exchanger 4-1 in the outdoor unit module as a defrosting heat exchanger to execute, and entering a defrosting process.

The flow path switching device 3 is maintained in the power-on state, the defrosting throttle device 19 is controlled to be opened and the air side valve 18 is closed, the defrosting switching device 21 is de-energized, the defrosting switching device 20 is energized, the outdoor fan 5-1 is turned off, the liquid pipe throttle device 6-1 is turned off, the throttle device 28 is opened, and the remaining devices in the outdoor unit module W1 are maintained in the same state as in the normal heating operation mode.

The flow path switching device 3, the flow path adjusting device 19, the air side valve 18, the defrosting switching device 20/21, the outdoor fan 5-1, the liquid pipe throttling device 6-1 and the throttling device 28 are all devices in the outdoor unit module W1.

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

In the second case, S1 is also correspondingly performed for the outdoor heat exchanger 4-1 in the outdoor unit module W2 and each device in the outdoor heat exchanger 4-2' in the outdoor unit module W2 remains the same as it is in the normal heating operation mode.

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

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 3D 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, the refrigerant is condensed and released to become liquid refrigerant, and then the refrigerant enters the liquid pipe throttling device 6-2 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 the high-temperature and high-pressure refrigerant is throttled to a proper pressure by the defrosting throttle device 19 and then enters the defrosting switching device 21D and C to enter the outdoor heat exchanger 4-1 for heat exchange defrosting.

The refrigerant which is heat exchanged from the outdoor heat exchanger 4-1 is throttled by the throttling device 28 and then is merged with the refrigerant which is discharged from the liquid pipe throttling device 6-2, then enters the outdoor heat exchanger 4-2 to be evaporated and absorbed heat, and is changed into a gas state, and the refrigerant which is discharged from the outdoor heat exchanger 4-2 enters the gas-liquid separator 14 through C and S of the defrosting switching device 20.

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

Regardless of the number of outdoor unit modules, when the outdoor heat exchangers in the outdoor unit modules are sequentially rotated for defrosting or combined rotated for defrosting, two outdoor heat exchangers in each outdoor unit module are rotated for defrosting.

If the defrosting heat exchanger exists in the outdoor unit module, the control of devices related to the defrosting heat exchanger in the outdoor unit module where the defrosting heat exchanger is located is the same.

For example, the outdoor heat exchanger 4-1 in the outdoor heat exchanger W1 is a defrosting heat exchanger, and the opening degree of the throttling device 28 is controlled and adjusted according to the outlet supercooling degree of the outdoor heat exchanger 4-1 and the target outlet supercooling degree range, so that the outlet supercooling degree of the outdoor heat exchanger 4-1 tends to be maintained in the target outlet supercooling degree range; according to the defrosting pressure and the target defrosting pressure range, the opening degree of the defrosting throttling device 19 is controlled and adjusted, so that the defrosting pressure of the compressor 1 tends to be maintained in the target defrosting pressure range, the outlet temperature and the defrosting pressure of the heat exchanger are ensured, the defrosting time is shortened, the defrosting speed and efficiency are improved, the capacity of an indoor unit can be maximized when the air conditioner continuously heats and defrosts, and the indoor thermal comfort of a user is improved.

When defrosting the outdoor heat exchanger 4-1, how to control the opening degree of the throttle device 28 and the opening degree of the defrosting throttle device 19 is described in detail with reference to fig. 2.

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

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 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': and calculating the supercooling Te1sco 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 Pf (detected by the pressure sensor 221) and the outlet temperature Te1 (detected by the temperature sensor 231) of the outdoor heat exchanger 4-1.

That is, Te1sc = Tec-Te1, where Tec is the corresponding saturation temperature at the defrost pressure Pf, which can be obtained by prior art queries.

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

s31': if the outlet supercooling degree Te1sc is within the target outlet supercooling degree range, keeping the opening degree of the throttling device 28 and executing to S4'; if not, the opening degree of the throttle device 28 is adjusted, and the process proceeds to S4'.

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

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 28 is increased by one adjustment step number, and execution is carried out to S4'.

That is, the next opening EV28(n +1) = EV28(n) + Δ EV28 of the throttle device 28, where Δ EV28 is the number of adjustment steps, where the number of adjustment steps can be selected to be 0.1% -10% pls (i.e., the number of steps) of the total opening.

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 throttling means 28 is decreased by one adjustment step number, and execution is carried out to S4'.

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

S4': whether the defrosting pressure Pf is within the target defrosting pressure range is compared, if so, the opening degree of the defrosting throttle device 19 is maintained and execution is performed to S2, and if not, the opening degree of the defrosting throttle device 19 is adjusted and execution is performed to S2.

The process of specifically adjusting the opening degree of the defroster throttle 19 is described as follows.

S41': if the defrost pressure Pf is within the target defrost pressure range, the opening degree of the defrost throttle 19 is maintained, and execution proceeds to S2.

S42': if the defrost pressure Pf is greater than the upper limit value of the target defrost pressure range, the opening degree of the defrost throttle 19 is decreased by one adjustment step number, and execution goes to S2.

That is, the next opening EV19(n +1) = EV19(n) - Δ EV19 of the defroster 19, where Δ EV19 is the number of adjustment steps, where the number of adjustment steps can 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 defroster 19 is increased by one adjustment step number and the process goes to S2.

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

S2: and judging whether the defrosting is finished or not, if so, exiting the defrosting process, otherwise, returning to S2', and adjusting the opening degrees of the throttling device 28 and the defrosting throttling device 19 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 devices 28 and the defroster throttle device 19, 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 at least comprises the following steps:

(1) controlling the defrosting switching device 21 to be electrified to enable the gas side of the defrosting heat exchanger 4-1 to be communicated with the gas-liquid separator 14;

(2) opening an outdoor fan 5-1;

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

in the defrosting process, the indoor side throttling devices 10-1 and 10-2 maintain control before defrosting, the throttling device 6-2 maintains normal heating control, namely, the outlet superheat degree Ts2 of the outdoor heat exchanger 4-2 is controlled, namely, the temperature sensor 233 detects the temperature T of a main gas pipe, the pressure sensor 222 detects the pressure P of the main gas pipe, the outlet superheat degree Ts2 of the outdoor heat exchanger 4-2 is the difference between the temperature T of the main gas pipe and the saturation temperature corresponding to the pressure P of the main gas pipe, and the outlet superheat degree Ts2 is controlled within 0-2 ℃.

Similarly, when the outdoor heat exchanger 4-1 is out of defrosting and the outdoor heat exchanger 4-2 is defrosting, the throttling device 6-1 is also used for controlling the outlet superheat degree of the outdoor heat exchanger 4-1 within 0-2 ℃.

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 defrosting throttle device 19 is kept open and the gas side valve 18 is closed, the power-off defrosting switching device 20 is controlled, the throttle device 28 is opened, the outdoor fan 5-2 and the liquid pipe throttle device 6-2 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 as the defrosting process of the outdoor heat exchanger 4-1.

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

Similarly, after the outdoor heat exchanger 4-2 exits defrosting, one of the outdoor heat exchangers to be defrosted in the outdoor unit module W2 (for example, the outdoor heat exchanger 4-1 'is implemented as a defrosting heat exchanger), and the outdoor heat exchanger 4-2' in the outdoor unit module W2 performs a normal heating operation process.

The above description mainly describes the control of each device of the outdoor unit module where the defrosting heat exchanger is located when the defrosting is sequentially switched. Similarly, when the outdoor heat exchangers in the outdoor unit modules W1 and W2 are combined and rotated for defrosting, the defrosting heat exchangers in the outdoor unit modules are defrosted by the defrosting control method as described above for each outdoor unit module.

And when all defrosting heat exchangers defrosting simultaneously meet defrosting ending conditions, defrosting can be ended and a normal heating operation mode is entered.

Referring to fig. 1, for example, when the outdoor heat exchanger 4-1 and the outdoor heat exchanger 4-1' perform combined defrosting, the outdoor heat exchanger 4-1 and the outdoor heat exchanger 4-1' simultaneously enter defrosting, and the outdoor heat exchanger 4-2' function as evaporators.

In the defrosting process, the outdoor unit module W1 is defrosted by the defrosting process described above for the outdoor heat exchanger 4-1, and the outdoor unit module W2 is defrosted by the defrosting process described above for the outdoor heat exchanger 4-1', and the specific process is described above and is not described herein again.

And after the outdoor heat exchanger 4-1 and the outdoor heat exchanger 4-1' both meet the defrosting ending condition, the defrosting process is quitted and the normal heating operation mode is entered.

For example, whether the defrosting time period T1 reaches the first preset time T1, or whether both the outlet temperature Te1 of the outdoor heat exchanger 4-1 and the outlet temperature Te1 'of the outdoor heat exchanger 4-1' are greater than or equal to the first preset temperature Tef and are 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.

Thereafter, the outdoor heat exchanger 4-2 and the outdoor heat exchanger 4-2' are subjected to combined defrosting.

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

[ three-pipe heating recovery function ]

The air conditioner of the present application may also be compatible with a three-pipe heat recovery function, see fig. 3, which shows a system structure diagram of the air conditioner with both two-pipe and three-pipe.

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

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

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

The two-regulation and the three-regulation are realized by switching the first switching valve a and the second switching valve b.

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

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

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

The main cooling operation mode, that is, the indoor unit is in both cooling and heating states, and the cooling load is greater than the heating load, and the outdoor heat exchanger serves as a condenser.

In the main cooling operation mode, it is assumed that the indoor heat exchanger 11-1 serves as an evaporator (i.e., the indoor heat exchanger 11-1 cools down) and the indoor heat exchanger 11-2 serves as a condenser (i.e., the indoor heat exchanger 11-2 heats up).

Referring to fig. 3, the flow path switching device 3 in the outdoor unit module W1 is powered on, the defrost orifice 19 is at an arbitrary opening degree, the air side valve 18 is opened, the defrost switching devices 21 and 20 are both de-energized, the liquid pipe orifice devices 6-1 and 6-2 are both opened, the outdoor fans 5-1 and 5-2 are both opened, the orifice device 28 is at an arbitrary opening degree, the first switching valve a (i.e., the first switching valve 24 a) connected to the indoor heat exchanger 11-1 is controlled to be closed and the second switching valve b (i.e., the second switching valve 24 b) is controlled to be opened, the first switching valve a (i.e., the first switching valve 25 a) connected to the indoor heat exchanger 11-2 is controlled to be opened and the second switching valve b (i.e., the second switching valve 25 b) is.

Wherein the defrost switch 21 and 20 are de-energized, wherein D and C are in communication and E and S are in communication.

The flow path switching device 3 is electrified, the D and the E are communicated, the C and the S are communicated, the compressor 1 compresses a low-temperature and low-pressure refrigerant into a high-temperature and high-pressure state, and the refrigerant is divided into two parts after passing through the one-way valve 2.

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

The other part of high-temperature and high-pressure refrigerant enters the indoor heat exchanger 11-2 through the gas side stop valve 13, the first extension pipe 12 and the first switching valve 25a through the flow path switching device 3, is subjected to internal heat exchange, is condensed and releases heat to form liquid refrigerant, then the refrigerant passes through the indoor machine side throttling device 10-2, is merged with the refrigerant from the outdoor side through the liquid side stop valve 8 and the second extension pipe 9, enters the indoor machine side throttling device 10-1, is throttled and depressurized to be in a gas-liquid state.

Then, the refrigerant enters the indoor heat exchanger 11-1 to be evaporated and absorbed heat, turns into a gaseous state, enters the gas-liquid separator 14 through the second switching valve 24b, the extension pipe 26, and the gas-side shutoff valve 27, and is finally sucked into the compressor 1 to be compressed, thereby completing the main refrigeration cycle.

The main heating mode, i.e., the indoor unit has two states of cooling and heating, and the heating load is greater than the cooling load, when the outdoor heat exchanger is used as an evaporator.

In the main heating mode, it is assumed that the indoor heat exchanger 11-1 serves as a condenser (i.e., the indoor heat exchanger 11-1 heats) and the indoor heat exchanger 11-2 serves as an evaporator (i.e., the indoor heat exchanger 11-2 cools).

Referring to fig. 3, the flow path switching device 3 in the outdoor unit module is powered on, the defroster throttle device 19 is at an arbitrary opening degree, the air side valve 18 can be selectively opened or closed (preferably closed), the defroster switching devices 21 and 20 are powered on, the pipe throttle devices 6-1 and 6-2 are opened, the outdoor fans 5-1 and 5-2 are opened, the throttle device 28 is at an arbitrary opening degree, the first switching valve 24a is controlled to be opened and the second switching valve 24b is controlled to be closed, the first switching valve 25a is controlled to be closed and the second switching valve 25b is controlled to be opened.

Wherein D and E are in communication and C and S are in communication when the defrost switch 21 and 20 are powered up.

The flow path switching device 3 is electrified, D and E are communicated, C 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 enters the indoor heat exchanger 11-1 through the check valve 2, D and E of the flow path switching device 3, the gas side stop valve 13, the first extension pipe 12 and the first switching valve 24a to be subjected to internal heat exchange, then is condensed and releases heat to form a liquid refrigerant, and then the refrigerant flows out through the indoor machine side throttling device 10-1 and is divided into two parts.

And a part of the refrigerant enters the liquid pipe throttling devices 6-1 and 6-2 through the second extension pipe 9 and the liquid side stop valve 8 to be throttled to a low-temperature low-pressure gas-liquid two state, then enters the outdoor heat exchangers 4-1 and 4-2 to be evaporated and absorbed, and is changed into a gas state, and the refrigerant coming out of the outdoor heat exchangers 4-1 and 4-2 flows out through C and S of the defrosting switching devices 21 and 20.

The other part is throttled and depressurized by the indoor unit-side throttle device 10-2 to enter the indoor heat exchanger 11-2 to be evaporated and absorbed heat, and is changed into a gas state, and then the gas state is merged with the refrigerant flowing out through the defrosting switching devices 21 and 20 as described above through the second switching valve 25b, the extension pipe 26, and the gas-side stop valve 27, and then enters the gas-liquid separator 14, and finally is sucked into the compressor 1 to be compressed, thereby completing the main heating cycle.

In the heating and defrosting operation mode in the main heating operation mode, the indoor unit is in two states of cooling and heating, the heating load is greater than the cooling load, and the plurality of outdoor heat exchangers in the outdoor unit modules W1 and W2 perform sequential alternate defrosting or combined alternate defrosting.

In the heating and defrosting operation mode in the main heating operation mode, the process of performing sequential or combined alternate defrosting by the plurality of outdoor heat exchangers in the outdoor unit modules W1 and W2 maintains the same state as the two-pipe air conditioner in sequential or combined alternate defrosting as described above, except for the control of the plurality of first switching valves a, the plurality of second switching valves b, and the indoor-side throttling devices 10-1 and 10-2.

In the heating defrost mode of operation in the main heating mode, it is assumed that the indoor heat exchanger 11-1 is used as a condenser (i.e., the indoor heat exchanger 11-1 heats) and the indoor heat exchanger 11-2 is used as an evaporator (i.e., the indoor heat exchanger 11-2 cools), and the outdoor heat exchanger 4-1 is a defrost heat exchanger.

Referring to fig. 3, the flow path switching device 3 in the outdoor unit module is powered on, the defrost orifice 19 is opened, the gas side valve 18 is closed, the defrost switching device 21 is powered off and the defrost switching device 20 is powered on, the liquid pipe orifice 6-1 is closed and the liquid pipe orifice 6-2 is opened, the outdoor fan 5-1 is closed and the outdoor fan 5-2 is opened, the orifice 28 is opened, the first switching valve 24a is controlled to be opened and the second switching valve 24b is controlled to be closed, the first switching valve 25a is controlled to be closed and the second switching valve 25b is controlled to be opened.

Wherein the defrost switch 21 is de-energized, wherein D and C are in communication and E and S are in communication. When the defrost switch 20 is powered up, D and E are communicated and C and S are communicated.

The flow path switching device 3 is electrified, the D and the E are communicated, the C and the S are communicated, the compressor 1 compresses low-temperature and low-pressure refrigerants into a high-temperature and high-pressure state, and the refrigerant is divided into two paths after passing through the one-way valve 2.

One path is throttled to a proper pressure by the defrosting throttling device 19 and then enters the defrosting switching device 21D and C to enter the outdoor heat exchanger 4-1 for heat exchange defrosting.

The refrigerant which is heat exchanged from the outdoor heat exchanger 4-1 flows out after being throttled by the throttling device 28.

The other path enters the indoor heat exchanger 11-1 through the flow path switching device 3D and E, the gas side stop valve 13, the first extension pipe 12 and the first switching valve 24a for heat exchange, is condensed and releases heat to form liquid refrigerant, and then the refrigerant flows out through the indoor machine side throttling device 10-1 and is divided into two parts.

One part of the refrigerant enters the liquid pipe throttling device 6-2 through the second extension piping 9 and the liquid side stop valve 8 to be throttled to a low-temperature low-pressure gas-liquid two state, then enters the outdoor heat exchanger 4-2 to be evaporated and absorbed, and is changed into a gas state, and the refrigerant coming out of the outdoor heat exchanger 4-2 and the refrigerant throttled and flowing out through the throttling device 28 are converged and then flow out through the defrosting switching device 20C and S.

The other part is throttled and depressurized by the indoor unit-side throttle device 10-2 to enter the indoor heat exchanger 11-2 to be evaporated and absorbed heat, and then changed into a gas state, and then the gas state is merged with the refrigerant flowing out through the above-mentioned C and S defrosting switching devices 20 by passing through the second switching valve 25b, the extension pipe 26, and the gas-side stop valve 27, and then enters the gas-liquid separator 14, and finally is sucked into the compressor 1 to be compressed, thereby completing the heating and defrosting mode in the main heating cycle. In relation to the three-pipe heat recovery function, referring to fig. 3, when performing the alternate defrosting, the control of each of the outdoor unit modules W1 and W2 is the same as the control of each of the outdoor unit modules W1 and W2 in the two-pipe air conditioner.

[ separation of wind field ]

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

The outdoor fans 5-1 and 5-2 are 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 corresponding outdoor fan 5-2 of the outdoor heat exchanger 4-2 is kept in operation when the outdoor heat exchanger 4-1 is defrosted, in order to avoid the situation that the outdoor heat exchanger 4-1 cannot be defrosted effectively due to the wind field generated by the outdoor fan 5-2 blowing through the outdoor heat exchanger 4-1, a separating device 101 for separating the wind field is provided in the present application (see patent document with application number 262610279447.2 entitled "outdoor unit of air conditioner").

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

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

Thus, when the outdoor heat exchanger 4-1 performs defrosting, since the partition 101 separates the first wind field and the second wind field, the first wind field is not affected even if the outdoor fan 5-2 is still operated.

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.

And 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 of the outdoor heat exchanger 4-2 is turned off.

Similarly, the outdoor unit module W2 also has the separating device therein for separating the adjacent wind fields formed between the outdoor fan and the corresponding outdoor heat exchangers 4-1'/4-2' in the outdoor unit module W2, thereby improving the effectiveness of the alternate defrosting in the outdoor unit module W2 and improving the thermal comfort in the room.

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.

Claims

1. An air conditioner, comprising:

at least one indoor unit;

a plurality of outdoor unit modules, each outdoor unit module comprising:

a compressor;

a defrost throttle for throttling a portion of refrigerant from the compressor;

an air side valve connected in parallel with the defrost throttling device;

two outdoor heat exchangers arranged in parallel;

2. The air conditioner according to claim 1,

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

3. The air conditioner according to claim 1,

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:

controlling to open the defrosting throttle device, and controlling the opening of the defrosting throttle device 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;

4. The air conditioner according to claim 3,

adjusting the opening degree of the throttling device, specifically:

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 opening degree of the defrosting throttle device, specifically:

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

6. The air conditioner of claim 5, wherein the defrost heat exchanger exits the defrost process and enters a normal heating operation process comprising at least:

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 according to claim 1, further comprising:

a plurality of first switching valves connected in parallel, each corresponding to one indoor unit, for branching at least a part of the refrigerant from the compressor switched by the flow switching device of each outdoor unit module, and corresponding to a gas side of an indoor heat exchanger flowing into the indoor unit;

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

a separation device for separating adjacent wind farms;

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