CN115031350A

CN115031350A - Air conditioner and defrosting control method thereof

Info

Publication number: CN115031350A
Application number: CN202210757838.XA
Authority: CN
Inventors: 邹海如; 陈海群; 李林
Original assignee: Hisense Guangdong Air Conditioning Co Ltd
Current assignee: Hisense Guangdong Air Conditioning Co Ltd
Priority date: 2022-06-30
Filing date: 2022-06-30
Publication date: 2022-09-09
Anticipated expiration: 2042-06-30
Also published as: CN115031350B

Abstract

The invention discloses an air conditioner and a defrosting control method thereof, wherein the air conditioner comprises: the system comprises a compressor, a four-way valve, an outdoor heat exchanger, a flash evaporator, a switch valve, an indoor heat exchanger, a first one-way valve, a first throttle device, a second one-way valve, a second throttle device and a controller, wherein the switch valve is arranged on a pipeline between an air outlet pipe of the flash evaporator and an air suction port of the compressor; the first check valve and the first throttler are arranged between the first liquid pipe of the flash evaporator and the indoor heat exchanger in parallel, and a liquid inlet of the first check valve is connected with the first liquid pipe; the second check valve and the second throttler are arranged between the second liquid pipe of the flash evaporator and the outdoor heat exchanger in parallel, and a liquid inlet of the second check valve is connected with the second liquid pipe; a controller is connected with the switch valve, the controller is configured to: and detecting that the air conditioner is switched to a defrosting mode, recording the accumulated time of the air conditioner in the defrosting mode, determining that the accumulated time is lower than a first time threshold, and controlling the switch valve to be switched on.

Description

Air conditioner and defrosting control method thereof

Technical Field

The invention relates to the technical field of air conditioners, in particular to an air conditioner and a defrosting control method of the air conditioner.

Background

Winter is when outdoor ambient temperature is lower, during the long-time operation mode of heating of air conditioner, the off-premises station of air conditioner is evaporation side and is easily frosted, and then can lead to heating the effect and descend, and thick along with the increase frost layer of frosting time, the frost layer can increase the heat transfer thermal resistance of the outer machine of air-conditioner, lead to outdoor air circulation area to reduce, the flow resistance increases, can lead to the amount of wind of off-premises station to reduce, and then can make outdoor evaporating temperature further reduce, the heat exchange worsens, and reduce indoor environment travelling comfort, can't satisfy user's demand, reduce user experience. Therefore, after the air conditioner operates for a period of time, it needs to be effectively defrosted in time. The existing defrosting technologies mainly comprise refrigeration mode (reverse cycle) defrosting, bypass defrosting and phase-change energy storage defrosting.

The air conditioner generally adopts a refrigeration mode (reverse cycle) defrosting mode, namely a conventional defrosting mode, in the related art, when the outdoor unit is defrosted by adopting the conventional defrosting mode, after the outdoor unit enters the defrosting mode, a low-temperature refrigerant enters the indoor heat exchanger to absorb heat so as to frost the indoor heat exchanger, when defrosting is completed and heating is performed again, the condition that defrosting needs to be performed on the indoor unit possibly occurs, the heating effect is poor, and the comfort level of a user is reduced.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, an object of the present invention is to provide an air conditioner, which prevents the outdoor heat exchanger from frosting during defrosting, thereby avoiding the situation of poor heating effect when defrosting is completed and heating is resumed, and improving the comfort of users.

Another objective of the present invention is to provide a defrosting control method for an air conditioner.

In order to achieve the above object, an embodiment of a first aspect of the present invention provides an air conditioner, including: the flash evaporator is provided with a first liquid pipe, a second liquid pipe and an air outlet pipe, and the air outlet pipe is connected with an air suction port of the compressor; the switch valve is arranged on a pipeline between the air outlet pipe and the air suction port of the compressor; the first check valve and the first throttling device are arranged between a first liquid pipe of the flash evaporator and the indoor heat exchanger in parallel, and a liquid inlet of the first check valve is connected with the first liquid pipe; the second check valve and the second throttling device are arranged between a second liquid pipe of the flash evaporator and the outdoor heat exchanger in parallel, and a liquid inlet of the second check valve is connected with the second liquid pipe; a controller connected with the switching valve, the controller configured to: and when the condition that the air conditioner is switched to a defrosting mode is detected, recording the accumulated time of the air conditioner running in the defrosting mode, determining that the accumulated time is lower than a first time threshold value, and controlling the switch valve to be switched on.

According to the air conditioner provided by the embodiment of the invention, the flash evaporator is arranged in the refrigerant loop between the outdoor heat exchanger and the indoor heat exchanger, the switch valve is arranged between the flash evaporator and the air suction port of the compressor, in the defrosting mode, the switch valve is controlled to be connected, so that most of the liquid refrigerant which is cooled and decompressed by the second throttle device into low-temperature low-pressure liquid refrigerant is directly drained back to the compressor through the switch valve, only a small amount of the low-temperature low-pressure liquid refrigerant can flow through the indoor heat exchanger to ensure that the indoor heat exchanger cannot frost, the problem of poor heating effect caused by defrosting of the indoor unit when defrosting is finished and the heating mode is entered again can be avoided, and the comfort level of users is improved.

In some embodiments of the present invention, the air conditioner further comprises: the temperature sensor is used for acquiring the temperature of the outdoor coil pipe; the controller is connected with the temperature sensor and is further configured to: and determining that the accumulated time of the air conditioner running in the defrosting mode is higher than the first time threshold, and controlling the switch valve to be switched on or switched off according to the accumulated time and the temperature of the outdoor coil. The control switch valve is controlled to be switched on or switched off according to the accumulated time and the temperature of the outdoor coil pipe, the targeted defrosting operation under different working conditions can be realized, when the control switch valve is switched on, the effective defrosting of the outdoor unit can be realized, the frosting of the indoor unit can be guaranteed, the comfort level of a user is improved, and when the control switch valve is switched off, the defrosting of the outdoor unit can be quickly carried out, and the problem that the defrosting of the outdoor unit is not clean is avoided.

In some embodiments of the present invention, the controller is further configured to determine whether the accumulated time is higher than a second time threshold if the outdoor coil temperature is lower than a first temperature threshold, and control the on-off valve to turn off if the accumulated time is higher than the second time threshold and lower than a third time threshold, until the accumulated time is higher than the third time threshold, and control the air conditioner to exit the defrosting mode, wherein the third time threshold > the second time threshold > the first time threshold. When the accumulated time is determined to be higher than a third time threshold value, the defrosting time is considered to be long enough, and the frost layer in the outdoor unit can be completely removed, so that the air conditioner is controlled to exit the defrosting mode.

In some embodiments of the present invention, the controller is further configured to determine whether the accumulated time reaches a third time threshold if the outdoor coil temperature is higher than the first temperature threshold and lower than a second temperature threshold, and control the on-off valve to remain on until the accumulated time reaches the third time threshold if the accumulated time does not reach the third time threshold, and control the air conditioner to exit the defrosting mode, wherein the second temperature threshold is greater than the first temperature threshold, and the third time threshold is greater than the first time threshold. When the frost amount in the outdoor unit is basically in a normal state, the outdoor unit can be defrosted in a mode of controlling the switch valve to be switched on, the defrosting time is long, the outdoor unit can be defrosted completely, the indoor heat exchanger cannot frost in the defrosting process, and the situations that the heating effect is poor and the like caused by defrosting of the indoor unit when defrosting is finished and the indoor unit enters the heating mode again are avoided

In some embodiments of the present invention, the air conditioner is further configured to determine whether the accumulated time reaches a second time threshold or whether the accumulated time reaches a third time threshold if the outdoor coil temperature is higher than a second temperature threshold, and control the air conditioner to exit the defrosting mode if the accumulated time reaches the second time threshold or the third time threshold. Wherein, through real-time detection outdoor coil temperature, can know the off-premises station in real time and frost or the defrosting condition, and because the off-premises station condition of frosting, the different defrosting modes of adaptability switching, in order to reach corresponding defrosting effect, can promote the defrosting ability to the off-premises station, in order to realize quick defrosting, even can also guarantee to defrost well under operating mode such as low temperature high humidity, can also when operation defrosting mode, ensure that indoor heat exchanger can not frosted, and then can avoid need to change the frost to the indoor set and the problem that the heating effect that causes when defrosting is accomplished and reentrant heating mode, promote user's comfort level

In order to achieve the above object, a second aspect of the present invention provides a defrosting control method for an air conditioner, which is used for the air conditioner described in the above embodiment, and the method includes: detecting that the air conditioner is switched to a defrosting mode; recording the accumulated time of the air conditioner running in the defrosting mode; and determining that the accumulated time is lower than a first time threshold value, and controlling a switch valve between an air outlet pipe of the flash evaporator and an air suction port of the compressor to be switched on.

According to the defrosting control method of the air conditioner provided by the embodiment of the invention, in the defrosting mode, the switch valve is controlled to be connected, so that most of the low-temperature low-pressure liquid refrigerant which is cooled and depressurized by the second throttling device is directly drained back to the compressor through the switch valve, and only a few low-temperature low-pressure liquid refrigerants flow through the indoor heat exchanger, so that the indoor heat exchanger is ensured not to frost, the problem of poor heating effect caused by defrosting of the indoor unit when defrosting is finished and the heating mode is entered again is solved, and the comfort level of a user is improved.

In some embodiments of the invention, the method further comprises: acquiring the temperature of an outdoor coil pipe; and controlling the switch valve to be switched on or switched off according to the accumulated time and the temperature of the outdoor coil.

In some embodiments of the present invention, controlling the on-off valve to turn on or off according to the accumulated time and the outdoor coil temperature comprises: if the temperature of the outdoor coil pipe is lower than a first temperature threshold value, judging whether the accumulated time is higher than a second time threshold value; and if the accumulated time is higher than the second time threshold and lower than a third time threshold, controlling the switching valve to be turned off until the accumulated time is higher than the third time threshold, and controlling the air conditioner to exit the defrosting mode, wherein the third time threshold is greater than the second time threshold and is greater than the first time threshold.

In some embodiments of the present invention, controlling the on-off valve to turn on or off according to the accumulated time and the outdoor coil temperature comprises: if the temperature of the outdoor coil pipe is higher than a first temperature threshold value and lower than a second temperature threshold value, judging whether the accumulated time reaches a third time threshold value; and if the accumulated time does not reach the third time threshold, controlling the switch valve to be kept on until the accumulated time reaches the third time threshold, and controlling the air conditioner to exit the defrosting mode, wherein the second temperature threshold is greater than the first temperature threshold, and the third time threshold is greater than the first time threshold.

In some embodiments of the present invention, controlling the on-off valve to turn on or off according to the accumulated time and the outdoor coil temperature comprises: if the temperature of the outdoor coil pipe is higher than a second temperature threshold, judging whether the accumulated time reaches a second time threshold or whether the accumulated time reaches a third time threshold, wherein the third time threshold is larger than the second time threshold and larger than the first time threshold; and if the accumulated time reaches the second time threshold or the third time threshold, controlling the air conditioner to exit the defrosting mode.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic diagram of an air conditioner;

FIG. 2 is a schematic diagram of an air conditioner according to one embodiment of the present invention;

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

FIG. 4 is a flowchart of a defrosting control method of an air conditioner according to an embodiment of the present invention;

fig. 5 is a flowchart of a defrosting control method of an air conditioner according to another embodiment of the present invention;

fig. 6 is a flowchart of a defrosting control method of an air conditioner according to still another embodiment of the present invention;

fig. 7 is a flowchart of a defrosting control method of an air conditioner according to still another embodiment of the present invention;

fig. 8 is a flowchart of a defrosting control method of an air conditioner according to still another embodiment of the present invention;

fig. 9 is a flowchart of a defrosting control method of an air conditioner according to still another embodiment of the present invention.

Reference numerals:

an air conditioner 100;

the system comprises a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a flash evaporator 4, an indoor heat exchanger 5, a switch valve 6, a first check valve 7, a first throttling device 8, a second check valve 9, a second throttling device 10, a controller 11 and a temperature sensor 12.

Detailed Description

Embodiments of the present invention will be described in detail below, the embodiments described with reference to the drawings being illustrative, and the embodiments of the present invention will be described in detail below.

The existing defrosting technologies mainly comprise refrigeration mode (reverse cycle) defrosting, bypass defrosting and phase-change energy storage defrosting. When the refrigeration mode is adopted for defrosting, the indoor heat exchanger is used as an evaporation end, the indoor unit may frost, and further the indoor unit needs to be defrosted when defrosting is completed and the heating mode is re-entered, so that the heating effect of the air conditioner is poor, and the comfort experience of a user is affected.

Therefore, the problem of poor heating effect caused by the fact that defrosting needs to be carried out on the indoor unit when defrosting is completed and the indoor unit enters the heating mode again can be avoided, and the comfort level of a user is improved.

Based on the above, in order to solve the problem that the indoor unit needs to be defrosted when entering the heating mode due to frosting of the indoor unit in the defrosting mode, so that indoor heat exchange is poor, the embodiment of the invention provides a defrosting control method of an air conditioner and the air conditioner adopting the method.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, 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 application.

Fig. 1 is a schematic view of an air conditioner, the basic structure of which can be understood in conjunction with fig. 1, in which the air conditioner performs a cooling/heating cycle of the air conditioner by using a compressor, a condenser, an expansion valve, and an evaporator. Wherein the refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation, and supplies a 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 high-temperature and high-pressure liquid-phase refrigerant condensed in the condenser into a low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve, and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor. The evaporator can achieve a refrigerating effect by heat exchange 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 the air conditioner refers to a portion of the system cycle including the compressor and the outdoor heat exchanger, the indoor unit of the air conditioner includes the indoor heat exchanger, and the expansion valve may be provided in the indoor unit or the outdoor unit.

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.

An air conditioner according to some embodiments of the present application includes an air conditioner indoor unit installed in an indoor space. The indoor unit, i.e., the indoor unit, is connected to an outdoor unit, i.e., the outdoor unit, installed in an outdoor space through a pipe. The outdoor unit of the air conditioner may be provided with a compressor, an outdoor heat exchanger, an outdoor fan, an expander and the like for system circulation, and the indoor unit of the air conditioner may be provided with an indoor heat exchanger and an indoor fan.

An air conditioner according to an embodiment of the present invention will be described below with reference to fig. 2 and 3.

In some embodiments of the present invention, as shown in fig. 2, a schematic diagram of an air conditioner according to an embodiment of the present invention is shown. The air conditioner 100 includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a flash evaporator 4, an indoor heat exchanger 5, a switch valve 6, a first check valve 7, a first restrictor 8, a second check valve 9, a second restrictor 10, and a controller 11.

The flash evaporator 4 has a first liquid pipe, a second liquid pipe and an air outlet pipe, and the air outlet pipe is connected with the air suction port of the compressor 1. Specifically, as shown in fig. 2, the gas outlet pipe is disposed at the upper part of the flash evaporator 4, and the first liquid pipe and the second liquid pipe are both disposed at the bottom of the flash evaporator 4. The flash evaporator 4 is used for decompressing the refrigerant flowing through, thereby establishing vapor-liquid equilibrium at a new pressure level.

The on-off valve 6 is provided on a pipe between the outlet duct 40 and the suction port of the compressor 1. The switch valve 6 may be an electronic expansion valve, and the switch valve 6 is used to control the flow direction of the refrigerant when opened or closed.

The first check valve 7 and the first throttler 8 are arranged between the first liquid pipe of the flash evaporator 4 and the indoor heat exchanger 5 in parallel, and a liquid inlet of the first check valve 7 is connected with the first liquid pipe. Specifically, when the first check valve 7 is turned on, the refrigerant flows out of the first liquid pipe of the flash evaporator 4 and flows into the indoor heat exchanger 5 through the first check valve 7, and when the first check valve 7 is turned off, the refrigerant flows out of the indoor heat exchanger 5 and flows into the first liquid pipe of the flash evaporator 4 through the first restrictor 8. The second check valve 9 and the second throttler 10 are arranged between the second liquid pipe of the flash evaporator 4 and the outdoor heat exchanger 3 in parallel, and a liquid inlet of the second check valve 9 is connected with the second liquid pipe. Specifically, when the second check valve 9 is turned on, the refrigerant flows out from the second liquid pipe of the flash evaporator 4 and flows into the outdoor heat exchanger 3 through the second check valve 9, and when the second check valve 9 is turned off, the refrigerant flows out from the outdoor heat exchanger 3 and flows into the second liquid pipe of the flash evaporator 4 through the second throttle 10. The first restrictor 8 and the second restrictor 10 are respectively a heating capillary tube and a cooling capillary tube, and can be replaced by restrictor devices such as a throttle valve or an electronic expansion valve.

The controller 11 is connected to the switch valve 6, wherein the controller 11 may be a Processor having data Processing and analyzing functions, such as a Central Processing Unit (CPU) in the air conditioner 100, and the like, and the controller 11 may include a monitoring Unit, a determining Unit, a control Unit, and the like for Processing and analyzing data.

Among them, it is understood that the indoor unit side of the air conditioner 100 is also provided with an indoor fan, and the outdoor unit side is provided with an outdoor fan. When the air conditioner 100 operates in the heating mode, the outdoor heat exchanger 3 serves as an evaporator and the indoor heat exchanger 5 serves as a condenser. Under the mode of heating, controller 11 control compressor 1 opens the operation, indoor fan opens, outdoor fan opens, cross valve 2 is gone up the electricity, ooff valve 6 opens, first check valve 7 closes and second check valve 10 switches on, and the discharge refrigerant flow direction of compressor 1 gas vent this moment is: an air outlet of a compressor 1, an E port of a four-way valve 2, an indoor heat exchanger 5, a first throttling device 8 and a flash evaporator 4. Further, the gas refrigerant separated in the flash evaporator 4 flows out of the gas outlet pipe of the flash evaporator 4 and flows back to the suction port of the compressor 1 through the switch valve 6. And the liquid refrigerant separated from the flash evaporator 4 enters the outdoor heat exchanger 3 to absorb heat and become gas refrigerant, and the flow direction of the gas refrigerant is as follows: the second liquid pipe of the flash evaporator 4, the second one-way valve 10, the outdoor heat exchanger 3, the port C of the four-way valve 2, the port S of the four-way valve 2, and the air suction port of the compressor 1, wherein two paths of refrigerants finally return to the liquid storage device of the compressor 1, are compressed by the compressor 1 again and are called high-temperature and high-pressure gas refrigerants to be discharged, and therefore refrigerant circulation in a heating mode is achieved.

In some embodiments of the invention, the controller 11 is configured to: it is detected that the air conditioner 100 is switched to the defrost mode.

In the heating mode, the outdoor heat exchanger 3 is likely to frost the outdoor unit after working as an evaporator for a long time, and at this time, the air conditioner 100 needs to be controlled to operate in the defrosting mode in time to defrost the outdoor unit.

In the defrosting mode, after passing through the four-way valve 2, the high-temperature and high-pressure gas refrigerant discharged from the exhaust port of the compressor 1 first enters the outdoor heat exchanger 3, and at this time, the outdoor heat exchanger 3 serves as a condenser and the indoor heat exchanger 5 serves as an evaporator. The high-temperature high-pressure gas refrigerant is condensed and radiated in the outdoor heat exchanger 3 to be changed into a medium-temperature medium-pressure liquid refrigerant, then enters the flash evaporator 4 to be cooled and decompressed, and finally is changed into a low-temperature low-pressure liquid refrigerant, and the switching valve 6 is arranged for distributing and controlling the flow direction of the low-temperature low-pressure liquid refrigerant, so that the defrosting effect of the outdoor unit is achieved. In the defrosting mode, the controller 11 controls the first check valve 7 to be turned on and controls the second check valve 9 to be turned off, that is, the on-off states of the first check valve 7 and the second check valve 9 in the defrosting mode are opposite to the on-off state in the heating mode, that is, the flow direction of the refrigerant in the circulation pipeline in the defrosting mode is opposite to the flow direction of the refrigerant in the heating mode.

In addition, in the defrosting mode, the controller 11 controls the compressor 1 to be operated in an on state, the outdoor fan and the indoor fan to be turned off, and controls the four-way valve 2 not to be powered on.

In other embodiments, the cumulative time that the air conditioner 100 operates in the defrost mode is recorded.

When the air conditioner 100 initially enters the defrosting mode, the compressor 1 is started to operate, so that the operation state of the compressor 1 may not be stable enough in an initial period of time, and therefore, the time for the air conditioner 100 to operate the defrosting mode needs to be accumulated so as to determine the operation state of the compressor 1, and meanwhile, in a subsequent defrosting operation process, the defrosting mode is adjusted according to the accumulated time for operating the defrosting mode.

In other embodiments, the accumulated time is determined to be below the first time threshold and the on-off valve 6 is controlled to be turned on.

Wherein, the first time threshold can be set according to the requirement, wherein, the first time threshold should be set to a smaller value, for example, 1min ≦ 5min of the first time threshold can be set, for example, 1min or 2min or 3min or 5min and so on can be set for the first time threshold. When the air conditioner 100 initially enters the defrosting mode, the controller 11 controls the compressor 1 to start operation, so that the operation state of the compressor 1 may not be stable enough in an initial period of time, and therefore, a first time threshold needs to be set, and the switching valve 6 is controlled to be turned on in the first time threshold.

Further, after the on-off valve 6 is turned on, the refrigerant discharged from the discharge port of the compressor 1 includes two flow directions, and the first flow direction is: an exhaust port of the compressor 1, a D port of the four-way valve 2, a C port of the four-way valve 2, the outdoor heat exchanger 3, the second throttle 10, the flash evaporator 4, the switch valve 6 and an air suction port of the compressor 1; the second path of flow direction is as follows: an exhaust port of the compressor 1, a D port of the four-way valve 2, a C port of the four-way valve 2, the outdoor heat exchanger 3, the second throttle 10, the flash evaporator 4, the first one-way valve 7, the indoor heat exchanger 5, an E port of the four-way valve 2, an S port of the four-way valve 2 and an air suction port of the compressor 1.

As can be seen from the above, in the defrosting mode, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 enters the outdoor heat exchanger 3 to be condensed to release heat, then enters the second throttle 10 to be cooled and depressurized to become a low-temperature and low-pressure liquid refrigerant, and then enters the flash evaporator 4, and the flow direction of the low-temperature and low-pressure liquid refrigerant can be distributed and controlled by the flash evaporator 4, wherein most of the low-temperature and low-pressure liquid refrigerant is directly guided to the compressor 1 to avoid frosting of the indoor heat exchanger 5. That is, when the switch valve 6 is in the on state, most of the low-temperature and low-pressure liquid refrigerant separated from the flash evaporator 4 is directly guided to the suction port of the compressor 1 through the switch valve 6, and only a small amount of the low-temperature and low-pressure liquid refrigerant flows to the suction port of the compressor 1 according to the second flow direction, so that the indoor heat exchanger 5 does not frost when the outdoor unit is defrosted, thereby avoiding the situation that the heating effect is poor due to defrosting of the indoor unit when the air conditioner 100 enters the heating mode again after defrosting is completed.

According to the air conditioner 100 provided by the embodiment of the invention, the flash evaporator 4 is arranged in the refrigerant loop between the outdoor heat exchanger 3 and the indoor heat exchanger 5, the switch valve 6 is arranged between the flash evaporator 4 and the suction port of the compressor 1, in the defrosting mode, the switch valve 6 is controlled to be switched on, so that most of the liquid refrigerant which is cooled and depressurized by the second throttling device 10 into low-temperature low-pressure liquid refrigerant is directly drained back to the compressor 1 through the switch valve 6, only a few low-temperature low-pressure liquid refrigerant can flow through the indoor heat exchanger 5, the indoor heat exchanger 5 is ensured not to frost, the problem of poor heating effect caused by defrosting of an indoor unit when defrosting is completed and the heating mode is entered again can be avoided, and the comfort of users is improved.

In some embodiments of the present invention, as shown in fig. 2, there is a block diagram of an air conditioner according to another embodiment of the present invention, wherein a temperature sensor 12 may be provided in a coil of the outdoor heat exchanger 3 for collecting an outdoor coil temperature. For example, when the temperature of the outdoor coil is relatively low, it indicates that a frost layer in the outdoor unit is relatively thick and frosts more, and the defrosting capability of the air conditioner 100 needs to be improved, and when the temperature of the outdoor coil is relatively high, it indicates that a frost layer in the outdoor unit is relatively thin and frosts less, and defrosting is relatively easy.

The controller 11 is connected to the temperature sensor 12, and is further configured to: and determining that the accumulated time of the air conditioner 100 running in the defrosting mode is higher than a first time threshold value, and controlling the switching valve 6 to be switched on or switched off according to the accumulated time and the outdoor coil temperature.

When the cumulative time of the air conditioner 100 operating the defrosting mode is higher than the first time threshold, it is determined that the operation of the compressor 1 tends to be stable, and at this time, the frosting condition in the outdoor unit needs to be further determined, so that the air conditioner 100 is controlled to perform a targeted defrosting operation according to the amount of frost in the outdoor unit.

The prior art also discloses a bypass defrosting mode, wherein when the bypass defrosting mode is adopted, the refrigerant can continuously enter an air conditioner indoor unit for heating, the air conditioner can still maintain the heating condition, and the heating cycle of a unit is not required to be changed. The other part of the air passes through the indoor heat exchanger, and the defrosting mode has the advantages that the indoor heat exchanger still keeps heating operation, namely, the air is in a high-temperature state during defrosting, so that the condition that the indoor unit frosts cannot occur, when defrosting is finished and the heating mode is entered again, the heating effect of the indoor unit is good, and the indoor comfort can be ensured by a bypass defrosting mode. However, the time of bypass defrosting is longer, which is more than 2 times of reverse cycle defrosting, the defrosting is slower, and the problems of incomplete defrosting and the like easily occur under some low-temperature and high-humidity working conditions.

When the air conditioner operates in a refrigeration mode (reverse cycle) for defrosting, i.e., a conventional defrosting mode, the refrigerant flows back to the compressor 1 through the indoor heat exchanger 5, evaporates and absorbs heat to be changed into a low-temperature and low-pressure gas refrigerant through the indoor heat exchanger 5, and absorbs heat again to be changed into high-temperature and high-pressure gas after flowing back to the compressor 1. In the embodiment, as can be seen from the above, when the switch valve 6 is in the on state, most of the low-temperature and low-pressure liquid refrigerant is directly guided into the compressor 1 to avoid the frosting of the indoor heat exchanger 5, the refrigerant does not pass through the indoor heat exchanger 5, which is equivalent to the lack of the link of increasing the heat of the refrigerant in the pipeline at one stage, and the refrigerant is compressed by the compressor 1 to become high-temperature and high-pressure gas, so that the heat of the refrigerant flowing through the outdoor heat exchanger 3 at this time is less than the heat of the refrigerant after being increased by the two-stage energy, and the defrosting effect is limited, and the outdoor unit is suitable for the situations of thin frost layer and less frost amount in the outdoor unit. When the temperature of the outdoor coil pipe is higher, the switch valve 6 can be controlled to be switched on, so that effective defrosting of the outdoor unit can be realized, frosting of the indoor unit can be guaranteed, and the comfort level of a user is improved.

In the defrosting mode, when the controller 11 controls the on-off valve 6 to be turned off, the flow direction of the refrigerant in the pipeline is as follows: the air exhaust port of the compressor 1, the D port of the four-way valve 2, the C port of the four-way valve 2, the outdoor heat exchanger 3, the second throttle 10, the flash evaporator 4, the first one-way valve 7, the indoor heat exchanger 5, the E port of the four-way valve 2, the S port of the four-way valve 2 and the air suction port of the compressor 1, namely, at the moment, when a refrigerant in a pipeline flows through the indoor heat exchanger 5 and the compressor 1, two-stage energy is increased, and heat is more, when the high-temperature and high-pressure gas refrigerant exchanges heat with the outdoor heat exchanger 3, more heat can be released, so that a better defrosting effect is achieved to achieve quick defrosting of an outdoor unit, on the basis, when the temperature of an outdoor coil pipe is lower, particularly under some special working conditions such as low temperature and high humidity, the switching valve 6 can be controlled to be switched off, and the outdoor unit can be defrosted quickly, and the problem that the outdoor unit is not completely defrosted is avoided.

According to the air conditioner 100 provided by the embodiment of the invention, the on-off of the switch valve 6 is controlled according to the accumulated time and the outdoor coil temperature, the targeted defrosting operation under different working conditions can be realized, when the switch valve 6 is controlled to be on, the effective defrosting of the outdoor unit can be realized, the frosting of the indoor unit can be ensured, the comfort level of a user is improved, and when the switch valve 6 is controlled to be off, the defrosting of the outdoor unit can be quickly carried out, and the problem that the defrosting of the outdoor unit is not clean is avoided.

In some embodiments of the present invention, the controller 11 is further configured to determine whether the accumulated time is greater than a second time threshold if the outdoor coil temperature is less than a first temperature threshold.

The first temperature threshold may be set as required, for example, the first temperature threshold may be set to be less than or equal to 5 ℃, for example, the first time threshold may be set to be-2 ℃ or 0 ℃ or 1 ℃ or 5 ℃, and the like. When the temperature of the outdoor coil is detected to be lower than the first temperature threshold value, the temperature of the outdoor coil is in a lower state, which indicates that frost is more in the outdoor unit and a frost layer is thicker. And a second time threshold value can be set according to needs, wherein the second time threshold value is set to be a value larger than the first time threshold value, for example, the second time threshold value is set to be smaller than or equal to 3min and smaller than or equal to 8min, for example, the second time threshold value can be set to be 3min, 5min, 7min, 8min and the like, the defrosting effect under the condition that the control switch valve 6 is switched on is judged by accumulating the time of the defrosting mode and detecting the temperature of the outdoor coil pipe in real time, and the flow direction of the refrigerant in the pipeline can be adjusted in time according to the defrosting effect.

In other embodiments, if the accumulated time is higher than the second time threshold and lower than the third time threshold, the on-off valve 6 is controlled to be turned off until the accumulated time is higher than the third time threshold, and the air conditioner 100 is controlled to exit the defrosting mode.

Wherein the third time threshold may be set as required, in particular, the third time threshold > the second time threshold > the first time threshold are required to be satisfied. For example, a third time threshold value of 6min or less may be set to 12min, for example, the third time threshold value may be set to 6min or 8min or 10min or 12min, and when it is determined that the accumulated time is greater than the second time threshold value and less than the third time threshold value, the time for which the switching valve 6 has been controlled to be turned on is longer, and the temperature of the outdoor coil is lower than the first temperature threshold value, which indicates that defrosting is slower when defrosting is performed by using the method, and in order to avoid that defrosting time is too long, defrosting force needs to be increased at this time, the switching valve 6 is controlled to be turned off, and defrosting capability of the outdoor unit is improved, so as to achieve quick defrosting.

In addition, when defrosting is performed by adopting a mode of controlling the switching-off of the switching valve 6, the temperature of the outdoor coil needs to be detected in real time, and when the temperature of the outdoor coil is determined to be greater than the first temperature threshold, the switching-on of the switching valve 6 can be controlled again, so that the condition that the indoor unit frosts when defrosting is performed by adopting the mode of controlling the switching-off of the switching valve 6 for a long time is avoided.

Based on the above, when the outdoor unit is defrosted by controlling the on-off valve 6 to be turned off for a long time, the indoor unit is easily frosted, the defrosting time by using the method needs to be limited, and when the accumulated time is determined to be higher than the third time threshold, the defrosting time is considered to be long enough, and the frost layer in the outdoor unit can be completely removed, so that the air conditioner 100 is controlled to exit the defrosting mode.

According to the air conditioner 100 of the embodiment of the present invention, in the defrosting mode, after the outdoor unit is defrosted by controlling the on-off of the switch valve 6 for a period of time, if the outdoor coil temperature is still at a low level, the defrosting capacity of the outdoor unit is timely improved, so as to achieve quick defrosting.

In some embodiments of the present invention, the controller 11 is further configured to determine whether the accumulated time reaches a third time threshold if the outdoor coil temperature is higher than the first temperature threshold and lower than the second temperature threshold.

Wherein, the second temperature threshold can be set according to the requirement, and the second temperature threshold should be larger than the first temperature threshold, for example, the second temperature threshold can be set to be 0 ℃ ≦ 10 ℃, for example, the first time threshold can be set to be 0 ℃ or 5 ℃ or 8 ℃ or 10 ℃ and so on.

When the temperature of the outdoor coil is detected to be higher than the first temperature threshold and lower than the second temperature threshold, the frost amount in the outdoor unit is considered to be normal at this time, and the outdoor unit can be defrosted by controlling the on-off valve 6 to be turned on.

In other embodiments of the present invention, the controller 11 is further configured to control the on-off valve 6 to remain on if the accumulated time does not reach a third time threshold, and control the air conditioner 100 to exit the defrosting mode until the accumulated time reaches the third time threshold, wherein the second temperature threshold is greater than the first temperature threshold, and the third time threshold is greater than the first time threshold.

The outdoor unit is continuously defrosted by means of controlling the switch-on of the switch valve 6 until the accumulated time reaches a third time threshold, defrosting is determined to be completed, the air conditioner 100 is controlled to exit from the defrosting mode in time, defrosting of the outdoor unit can be guaranteed to be clean, the indoor heat exchanger 5 cannot frost in the defrosting process can be guaranteed, and the situation that defrosting of the indoor unit is needed to be conducted when defrosting is completed and the indoor unit enters the heating mode again, so that the heating effect is poor and the like is avoided.

In some embodiments of the present invention, the air conditioner 100 is further configured to determine whether the accumulated time reaches the second time threshold or whether the outdoor coil temperature reaches a third temperature threshold if the outdoor coil temperature is higher than the second temperature threshold.

When the temperature of the outdoor coil is detected to be higher than the second temperature threshold value, the temperature of the outdoor coil is high, frosting of the outdoor unit is less, the outdoor unit can be defrosted in a mode of controlling the switching-on of the switching valve 6, defrosting time can be limited to be short, and meanwhile, the temperature of the outdoor coil needs to be detected in real time to judge defrosting effect of the outdoor unit.

In other embodiments, the air conditioner 100 is controlled to exit the defrost mode if the accumulated time reaches the second time threshold or if the outdoor coil temperature reaches the third temperature threshold.

When the accumulated time reaches the second time threshold, the defrosting mode running time is considered to be enough to achieve complete defrosting of the outdoor unit, and then the defrosting operation is determined to be completed at the moment. And, as can be seen from the above, the third temperature threshold is a higher temperature, and when it is detected that the temperature of the outdoor coil reaches the third temperature threshold, it indicates that the outdoor unit is defrosted completely, and it is necessary to control the air conditioner 100 to exit from the defrosting mode in time, so as to avoid the situations that the current of the compressor 1 is too large and the compressor 1 is tripped or damaged due to frostless and long-term defrosting of the outdoor heat exchanger 3.

Further, under the above defrosting condition, when the defrosting is performed by controlling the on-off valve 6 to be turned on, the outdoor coil temperature also needs to be detected in real time, when it is determined that the outdoor coil temperature is greater than the second temperature threshold, it indicates that the defrosting speed is relatively fast and the defrosting effect is relatively good, in order to avoid the situation that the defrosting mode is still continuously operated when the frost layer of the outdoor unit is completely removed, when it is determined that the accumulated time reaches the second time threshold or the outdoor coil temperature is higher than the second temperature threshold, the air conditioner 100 is timely controlled to exit from the defrosting mode, and the situations that the compressor is tripped due to overlarge current or the compressor 1 is damaged due to frostless and long-term defrosting of the outdoor heat exchanger 3 are avoided.

In summary, according to the air conditioner 100 provided in the embodiment of the present invention, the outdoor unit frosting or defrosting condition is known in time by detecting the outdoor coil temperature in real time, and different defrosting modes are adaptively switched based on the outdoor unit frosting condition to achieve a corresponding defrosting effect, so that the defrosting capability of the outdoor unit can be improved to achieve quick defrosting, defrosting can be ensured to be clean even under working conditions such as low temperature and high humidity, and the defrosting mode can be operated to ensure that the indoor heat exchanger 5 does not frost, thereby avoiding the problem of poor heating effect caused by defrosting the indoor unit when defrosting is completed and the heating mode is entered again, and improving the comfort level of users.

The air conditioner 100 according to the embodiment of the present invention has a good defrosting effect when operating the defrosting mode, as shown in table 1, when the air conditioner 100 according to the embodiment of the present invention performs defrosting by using the method of the above embodiment

In some embodiments of the present invention, a defrosting control method for an air conditioner is further provided, which is used for the air conditioner 100 in the above embodiments, wherein the air conditioner 100 in the embodiments of the present invention can be understood by referring to fig. 2 and fig. 3, and details are not repeated herein. As shown in fig. 4, a flowchart of an air conditioner defrost control method according to an embodiment of the present invention is shown, wherein the air conditioner defrost control method at least includes steps S1-S3, which are described as follows.

And S1, detecting that the air conditioner is switched to the defrosting mode.

In the heating mode, the outdoor heat exchanger is easy to frost an outdoor unit after being used as an evaporator to work for a long time, and at the moment, the air conditioner needs to be controlled to operate in a defrosting mode in time to defrost the outdoor unit. In the defrost mode, the outdoor heat exchanger now functions as a condenser and the indoor heat exchanger as an evaporator. After passing through the four-way valve, a high-temperature and high-pressure gas refrigerant discharged from an exhaust port of the compressor enters an outdoor heat exchanger, the high-temperature and high-pressure gas refrigerant is condensed and radiated in the outdoor heat exchanger to be changed into a medium-temperature and medium-pressure liquid refrigerant, then enters a flash evaporator to be cooled and decompressed, and finally is changed into a low-temperature and low-pressure liquid refrigerant, and the switching valve is arranged to distribute and control the flow direction of the low-temperature and low-pressure liquid refrigerant, so that the defrosting effect of the outdoor unit is achieved.

And S2, recording the accumulated time of the defrosting mode of the air conditioner.

When the air conditioner initially enters the defrosting mode, the compressor is started to operate, so that the operation state of the compressor may not be stable enough in the initial period of time, and therefore, the time for the air conditioner to operate the defrosting mode needs to be accumulated so as to determine the operation state of the compressor, and meanwhile, in the subsequent defrosting operation process, the defrosting mode is convenient to adjust according to the accumulated time for operating the defrosting mode.

And S3, determining that the accumulated time is lower than the first time threshold value, and controlling a switch valve between an air outlet pipe of the flash evaporator and an air suction port of the compressor to be switched on.

The first time threshold may be set as required, where the first time threshold should be set to a smaller value, for example, 1min ≦ 5min may be set, for example, the first time threshold may be set to 1min, or 2min, or 3min, or 5 min.

Further, the switching valves are controlled to be switched on within a first time threshold, and at this time, as can be known from fig. 1, the refrigerant discharged from the discharge port of the compressor includes two flow directions, where the first flow direction is: an exhaust port of the compressor 1, a D port of the four-way valve 2, a C port of the four-way valve 2, the outdoor heat exchanger 3, the second throttling device 10, the flash evaporator 4, the switching valve 6 and an air suction port of the compressor 1; the second path of flow direction is as follows: an exhaust port of the compressor 1, a D port of the four-way valve 2, a C port of the four-way valve 2, the outdoor heat exchanger 3, the second throttle 10, the flash evaporator 4, the first one-way valve 7, the indoor heat exchanger 5, an E port of the four-way valve 2, an S port of the four-way valve 2 and an air suction port of the compressor 1.

Therefore, in the defrosting mode, the high-temperature and high-pressure gas refrigerant discharged by the compressor enters the outdoor heat exchanger to be condensed to release heat, then enters the second throttler to be cooled and decompressed to become the low-temperature and low-pressure liquid refrigerant, and then the flash evaporator can distribute and control the flow direction of the low-temperature and low-pressure liquid refrigerant, wherein most of the low-temperature and low-pressure liquid refrigerant can be directly drained into the compressor to avoid frosting of the indoor heat exchanger, only a few of low-temperature and low-pressure liquid refrigerant flows to the suction port of the compressor according to the second path of flow direction, so that the control switch valve is switched on, the indoor heat exchanger cannot frost when the outdoor unit is defrosted, and the condition that the defrosting effect is poor due to the fact that the indoor unit needs to be defrosted when the air conditioner reenters into the heating mode after defrosting is completed is avoided.

Further, as shown in fig. 1, in the defrosting mode, the compressor 1 is also controlled to be operated, the first check valve 7 is controlled to be turned on, the second check valve 9 is controlled to be turned off, and the four-way valve 2 is controlled not to be powered on, and the air conditioner includes an indoor fan and an outdoor fan, and the outdoor fan and the indoor fan are also turned off.

In some embodiments of the present invention, as shown in fig. 5, a flowchart of an air conditioner defrosting control method according to another embodiment of the present invention is provided, wherein the air conditioner defrosting control method further includes steps S4 and S5, which are described as follows.

And S4, acquiring the temperature of the outdoor coil.

Therein, as shown in fig. 3, a temperature sensor 12 may be provided in the coil of the outdoor heat exchanger 3 for collecting the outdoor coil temperature. For example, when the temperature of the outdoor coil is relatively low, it indicates that a frost layer in the outdoor unit is relatively thick and frosts more and the defrosting capability of the air conditioner needs to be improved, and when the temperature of the outdoor coil is relatively high, it indicates that a frost layer in the outdoor unit is relatively thin and frosts less and defrosting is relatively easy.

And S5, controlling the on-off valve to be switched on or switched off according to the accumulated time and the outdoor coil temperature.

When the accumulated time of the air conditioner in the defrosting mode is higher than the first time threshold, it is determined that the operation of the compressor 1 tends to be stable, and at this time, the frosting condition in the outdoor unit needs to be further judged, so that the air conditioner is controlled to perform targeted defrosting operation according to the amount of frost in the outdoor unit.

The bypass defrosting mode disclosed in the prior art is slow in defrosting, and the problems of incomplete defrosting and the like easily occur under low-temperature and high-humidity working conditions.

Under the defrosting mode, when the ooff valve is the on-state, the liquid refrigerant of most low temperature low pressure can be avoided indoor heat exchanger frosting by direct drainage in compressor 1, the refrigerant does not pass through indoor heat exchanger, be equivalent to lacking the thermal link of refrigerant in the one-level promotion pipeline, and the refrigerant only becomes high-temperature high-pressure gas by the compressor compression, so the heat in the refrigerant that flows through in outdoor heat exchanger 3 this moment is less in the heat that is compared in the refrigerant after the two-stage energy promotes, defrosting effect is limited, be applicable to in the off-premises station frost layer than thinner, the condition that the frost volume is few. As shown in fig. 2 or fig. 3, when the control switch valve is turned off, the flow direction of the refrigerant in the pipeline is: the air exhaust port of the compressor 1, the D port of the four-way valve 2, the C port of the four-way valve 2, the outdoor heat exchanger 3, the second throttle 10, the flash evaporator 4, the first one-way valve 7, the indoor heat exchanger 5, the E port of the four-way valve 2, the S port of the four-way valve 2 and the air suction port of the compressor 1, namely, when a refrigerant in a pipeline passes through the indoor heat exchanger 5 and the compressor 1, two-stage energy is increased and heat is more, when the high-temperature and high-pressure gas refrigerant exchanges heat with the outdoor heat exchanger 3, more heat can be released, so that a better defrosting effect is achieved to achieve quick defrosting of an outdoor unit, based on the reason, when the temperature of an outdoor coil pipe is lower, particularly under some special working conditions such as low-temperature and high-humidity working conditions, the switching valve 6 can be controlled to be switched off, and the outdoor unit can be defrosted quickly, and the problem that the outdoor unit is not completely defrosted is avoided.

According to the above contents, when the temperature of the outdoor coil pipe is higher, the switch valve can be controlled to be switched on, so that effective defrosting of the outdoor unit can be realized, frosting of the indoor unit can be guaranteed, and the comfort level of a user is improved.

According to the defrosting control method of the air conditioner, the switch valve is controlled to be switched on or switched off according to the accumulated time and the temperature of the outdoor coil, the targeted defrosting operation under different working conditions can be realized, when the switch valve is controlled to be switched on, the outdoor unit can be effectively defrosted, the indoor unit can be frosted, the comfort level of a user is improved, and when the switch valve is controlled to be switched off, the outdoor unit can be defrosted quickly, and the problem that the outdoor unit is unclean in defrosting is avoided.

In some embodiments of the present invention, as shown in fig. 6, which is a flowchart of a defrosting control method of an air conditioner according to still another embodiment of the present invention, wherein the switching valve is controlled to be turned on or off according to the accumulated time and the outdoor coil temperature, i.e., the above step S5 may include steps S51 and S52, as follows.

And S51, if the temperature of the outdoor coil is lower than the first temperature threshold, judging whether the accumulated time is higher than a second time threshold.

The first temperature threshold may be set as required, for example, the first temperature threshold may be set to be less than or equal to 5 ℃, for example, the first time threshold may be set to be-2 ℃ or 0 ℃ or 1 ℃ or 5 ℃, and the like. When the temperature of the outdoor coil is detected to be lower than the first temperature threshold value, the temperature of the outdoor coil is in a lower state, which indicates that frost is more in the outdoor unit and a frost layer is thicker. And a second time threshold value can be set according to needs, wherein the second time threshold value is set to be a value larger than the first time threshold value, for example, the second time threshold value is set to be smaller than or equal to 3min and smaller than or equal to 8min, for example, the second time threshold value can be set to be 3min, 5min, 7min or 8min and the like, the defrosting effect under the condition that the control switch valve is switched on is judged by accumulating the time of the defrosting mode and detecting the temperature of the outdoor coil pipe in real time, and the flow direction of the refrigerant in the pipeline can be adjusted in time according to the defrosting effect.

And S52, if the accumulated time is higher than the second time threshold and lower than the third time threshold, controlling the switch valve to be turned off until the accumulated time is higher than the third time threshold, and controlling the air conditioner to exit the defrosting mode, wherein the third time threshold is larger than the second time threshold and larger than the first time threshold.

The third time threshold may be set as needed, for example, the third time threshold may be set to be 6min or less than or equal to 12min, for example, the third time threshold may be set to be 6min or 8min or 10min or 12min, and when it is determined that the accumulated time is greater than the second time threshold and less than the third time threshold and the outdoor coil temperature is less than the first temperature threshold, it indicates that the time for controlling the on-off valve to be turned on is relatively long, but the defrosting effect is not ideal, and in order to increase the defrosting speed, the defrosting force needs to be increased at this time, the on-off valve is controlled to be turned off, and the defrosting capability of the outdoor unit is improved, so as to achieve quick defrosting.

In addition, when defrosting is performed by adopting a mode of controlling the on-off of the switch valve, the temperature of the outdoor coil needs to be detected in real time, and when the outdoor coil is determined to be higher than the first temperature threshold, the switch valve can be controlled to be switched on again, so that the condition that the indoor unit is frosted when defrosting is performed by adopting a mode of controlling the on-off of the switch valve for a long time is avoided.

Based on the above, when the outdoor unit is defrosted by controlling the on-off valve to be turned off for a long time, the indoor unit is easily frosted, the defrosting time by adopting the method needs to be limited, and when the accumulated time is determined to be higher than the third time threshold, the defrosting time is considered to be long enough, and the frost layer in the outdoor unit can be completely removed, so that the air conditioner is controlled to exit the defrosting mode.

In some embodiments of the present invention, as shown in fig. 7, which is a flowchart of a defrosting control method of an air conditioner according to still another embodiment of the present invention, wherein the switching valve is controlled to be turned on or off according to the accumulated time and the outdoor coil temperature, that is, the above step S5 may further include steps S53 and S54, as follows.

S53, if the outdoor coil temperature is higher than the first temperature threshold and lower than the second temperature threshold, determining whether the accumulated time reaches a third time threshold.

Wherein, the second temperature threshold can be set according to the requirement, and the second temperature threshold should be larger than the first temperature threshold, for example, 0 ℃ ≦ second temperature threshold ≦ 10 ℃, for example, the first time threshold can be set as 0 ℃ or 5 ℃ or 8 ℃ or 10 ℃ and so on.

When the temperature of the outdoor coil is detected to be higher than the first temperature threshold and lower than the second temperature threshold, the frost amount in the outdoor unit is considered to be basically in a normal state at the moment, and the outdoor unit can be defrosted by controlling the switch valve to be switched on.

And S54, if the accumulated time does not reach a third time threshold, controlling the switch valve to be kept on until the accumulated time reaches the third time threshold, and controlling the air conditioner to exit the defrosting mode, wherein the second temperature threshold is greater than the first temperature threshold, and the third time threshold is greater than the first time threshold.

The outdoor unit is continuously defrosted by means of controlling the switch-on of the switch valve, defrosting is determined to be completed until the accumulated time reaches a third time threshold, the air conditioner is controlled to exit from the defrosting mode in time, defrosting of the outdoor unit can be guaranteed to be clean, frosting of an indoor heat exchanger in the defrosting process can be avoided, and the situation that defrosting of the indoor unit is needed when defrosting is completed and the indoor unit enters the heating mode again to cause poor heating effect and the like is avoided.

In some embodiments of the present invention, as shown in fig. 8, which is a flowchart of a defrosting control method of an air conditioner according to still another embodiment of the present invention, wherein the switching valve is controlled to be turned on or off according to the accumulated time and the outdoor coil temperature, that is, the above step S5 may further include steps S55 and S56, as follows.

S55, if the outdoor coil temperature is higher than the second temperature threshold, judging whether the accumulated time reaches the second time threshold or whether the outdoor coil temperature is higher than the second temperature threshold, wherein the third time threshold is larger than the second time threshold and larger than the first time threshold.

When the temperature of the outdoor coil is detected to be higher than the second temperature threshold value, the temperature of the outdoor coil is higher, frosting of the outdoor unit is less, the outdoor unit can be defrosted in a mode of controlling the switch-on of the switch valve, defrosting time can be limited to be shorter, and meanwhile, the temperature of the outdoor coil needs to be detected in real time to judge defrosting effect of the outdoor unit.

And S56, if the accumulated time reaches the second time threshold or the third time threshold, controlling the air conditioner to exit the defrosting mode.

When the accumulated time reaches the second time threshold, the defrosting mode running time is considered to be enough to achieve complete defrosting of the outdoor unit, and then the defrosting operation is determined to be completed at the moment. And as can be seen from the above, the third temperature threshold is a higher temperature, when it is detected that the temperature of the outdoor coil reaches the third temperature threshold, it indicates that the outdoor unit is defrosted completely, and the air conditioner needs to be controlled to exit from the defrosting mode in time, so as to avoid the situations that the compressor is tripped or damaged due to excessive current of the compressor caused by frostless and long-term defrosting of the outdoor heat exchanger.

Further, under the above defrosting condition, when defrosting is performed by means of controlling the on-off valve to be switched on, the temperature of the outdoor coil also needs to be detected in real time, when the temperature of the outdoor coil is determined to be greater than the second temperature threshold, it is indicated that the defrosting speed is relatively high and the defrosting effect is relatively good at this time, in order to avoid the situation that the defrosting mode is still continuously operated when the frost layer of the outdoor unit is completely removed, when the accumulated time is determined to reach the second time threshold or the temperature of the outdoor coil is higher than the second temperature threshold, the air conditioner is timely controlled to quit the defrosting mode, and the situations that the compressor is tripped or damaged due to overlarge current of the compressor caused by frostless and long-term defrosting of the outdoor heat exchanger are avoided.

In some embodiments of the present invention, as shown in fig. 9, a flowchart of an air conditioner defrost control method according to another embodiment of the present invention is provided, wherein the air conditioner defrost control method may include S101-S106, as follows.

S101, a user starts a heating mode.

S102, entering a heating mode.

S103, the compressor, the indoor fan and the outdoor fan are started, the switch valve is connected, and the four-way valve is powered on.

And S104, meeting the condition of entering a defrosting mode.

And S105, entering a defrosting mode.

S106, the compressor, the indoor fan and the outdoor fan are started, the switch valve is connected, and the four-way valve is powered off.

S107, accumulating the defrosting mode running time N, judging whether the condition that N is more than or equal to N1 and less than or equal to N2 is met, if the judgment result is yes, executing the step S108, and if the judgment result is no, returning to execute the step S106. Wherein N1 is the first time threshold, and N2 is the second time threshold.

And S108, acquiring the temperature TC of the outdoor coil.

S109, step B, detecting that TC < T1, wherein T1 is a first temperature threshold.

S110, determining that N is not less than N3 and N2, and turning off the switch valve, wherein N3 is a third time threshold.

S111, determining that N is larger than N3, exiting the defrosting mode, and returning to the step S102.

S112, step A, detecting that TC is larger than T2, and turning on the switch valve, wherein T2 is a second temperature threshold.

S113, determining that N is greater than N2 or detecting that TC is greater than T3, exiting the defrosting mode, and returning to execute the step S102, wherein T3 is a third temperature threshold.

S114, step C, detecting that T1 is more than or equal to TC and less than or equal to T2, and switching on the switch valve.

And S115, determining that N is less than or equal to N3, and continuing to operate the defrosting mode.

S116, determining that N is larger than N3, exiting the defrosting mode, and returning to execute the step S102.

In addition, when step S110 is executed, if T1 is detected to be less than or equal to TC, the control switch valve is turned on, namely, the step B is executed to the step C, and when the step C is executed, the step C is executed to the step A if TC & gt T2 is detected.

According to the defrosting control method of the air conditioner, provided by the embodiment of the invention, the frosting or defrosting condition of the outdoor unit can be known in real time by detecting the temperature of the outdoor coil in real time, different defrosting modes are adaptively switched based on the frosting condition of the outdoor unit to achieve the corresponding defrosting effect, the defrosting capacity of the outdoor unit can be improved to realize quick defrosting, the defrosting can be ensured to be clean even under the working conditions of low temperature, high humidity and the like, the indoor heat exchanger can be ensured not to be frosted when the defrosting mode is operated, the problem of poor heating effect caused by the fact that the indoor unit needs to be defrosted when the defrosting is finished and the heating mode is re-entered can be avoided, and the comfort level of users is improved.

Other configurations and operations of the air conditioner 100 and the like according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail herein.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An air conditioner, comprising:

the flash evaporator is provided with a first liquid pipe, a second liquid pipe and an air outlet pipe, and the air outlet pipe is connected with an air suction port of the compressor;

the switch valve is arranged on a pipeline between the air outlet pipe and the air suction port of the compressor;

the first check valve and the first throttling device are arranged between a first liquid pipe of the flash evaporator and the indoor heat exchanger in parallel, and a liquid inlet of the first check valve is connected with the first liquid pipe;

the second check valve and the second throttling device are arranged between a second liquid pipe of the flash evaporator and the outdoor heat exchanger in parallel, and a liquid inlet of the second check valve is connected with the second liquid pipe;

a controller connected with the switching valve, the controller configured to: and when the condition that the air conditioner is switched to a defrosting mode is detected, recording the accumulated time of the air conditioner running in the defrosting mode, determining that the accumulated time is lower than a first time threshold value, and controlling the switch valve to be switched on.

2. The air conditioner according to claim 1, further comprising:

the temperature sensor is used for acquiring the temperature of the outdoor coil pipe;

the controller is connected with the temperature sensor and is further configured to: and determining that the accumulated time of the air conditioner running in the defrosting mode is higher than the first time threshold, and controlling the switch valve to be switched on or switched off according to the accumulated time and the temperature of the outdoor coil.

3. The air conditioner of claim 2, wherein the controller is further configured to determine whether the accumulated time is greater than a second time threshold if the outdoor coil temperature is less than a first temperature threshold, and to control the on-off valve to turn off until the accumulated time is greater than a third time threshold and to exit the defrost mode if the accumulated time is greater than the second time threshold and less than the third time threshold, wherein the third time threshold > the second time threshold > the first time threshold.

4. The air conditioner of claim 2, wherein the controller is further configured to determine whether the accumulated time reaches a third time threshold if the outdoor coil temperature is higher than a first temperature threshold and lower than a second temperature threshold, and to control the on-off valve to remain on until the accumulated time reaches the third time threshold if the accumulated time does not reach the third time threshold, and to control the air conditioner to exit the defrost mode, wherein the second temperature threshold is greater than the first temperature threshold, and the third time threshold is greater than the first time threshold.

5. The air conditioner of claim 2, wherein the air conditioner is further configured to determine whether the accumulated time reaches a second time threshold or whether the accumulated time reaches a third time threshold if the outdoor coil temperature is greater than a second temperature threshold, and to control the air conditioner to exit the defrost mode if the accumulated time reaches the second time threshold or the third time threshold.

6. An air conditioner defrost control method for the air conditioner of claim 1, the method comprising:

detecting that the air conditioner is switched to a defrosting mode;

recording the accumulated time of the air conditioner running in the defrosting mode;

and determining that the accumulated time is lower than a first time threshold value, and controlling a switch valve between an air outlet pipe of the flash evaporator and an air suction port of the compressor to be switched on.

7. The air conditioner defrost control method of claim 6, further comprising:

acquiring the temperature of an outdoor coil;

and controlling the switch valve to be switched on or switched off according to the accumulated time and the temperature of the outdoor coil.

8. The air conditioner defrost control method of claim 7, wherein controlling the switching valve to be turned on or off according to the accumulated time and the outdoor coil temperature comprises:

if the temperature of the outdoor coil pipe is lower than a first temperature threshold value, judging whether the accumulated time is higher than a second time threshold value;

and if the accumulated time is higher than the second time threshold and lower than a third time threshold, controlling the switching valve to be turned off until the accumulated time is higher than the third time threshold, and controlling the air conditioner to exit the defrosting mode, wherein the third time threshold is greater than the second time threshold and is greater than the first time threshold.

9. The air conditioner defrost control method of claim 7, wherein controlling the switching valve to be turned on or off according to the accumulated time and the outdoor coil temperature comprises:

if the temperature of the outdoor coil pipe is higher than a first temperature threshold value and lower than a second temperature threshold value, judging whether the accumulated time reaches a third time threshold value;

and if the accumulated time does not reach the third time threshold, controlling the switch valve to be kept on until the accumulated time reaches the third time threshold, and controlling the air conditioner to exit the defrosting mode, wherein the second temperature threshold is greater than the first temperature threshold, and the third time threshold is greater than the first time threshold.

10. The air conditioner defrost control method of claim 7, wherein controlling the switching valve to be turned on or off according to the accumulated time and the outdoor coil temperature comprises:

if the temperature of the outdoor coil pipe is higher than a second temperature threshold, judging whether the accumulated time reaches a second time threshold or whether the accumulated time reaches a third time threshold, wherein the third time threshold is larger than the second time threshold and larger than the first time threshold;

and if the accumulated time reaches the second time threshold or the third time threshold, controlling the air conditioner to exit the defrosting mode.