KR101622617B1 - Air-conditioner and Control Method of the same - Google Patents

Abstract

A control method of an air conditioner according to an embodiment of the present invention includes a first oil level measurement step of measuring an oil level of a compressor or an oil separator, a step of measuring the oil level measured in the oil level measurement step, Determining whether the measured oil level is equal to or lower than a first level that is higher than a first level that is set in advance in the first oil level determination step; And a first capacity reducing operation step of operating the first capacity reducing operation step with a smaller operating capacity than the current operating capacity.

Compressor, oil separator, oil shortage, capacity reduction operation

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner and a control method thereof, and more particularly, to an air conditioner and a control method thereof that can prevent oil shortage of an oil separator or a compressor.

Generally, the air conditioner includes a compressor, a condenser, an expansion mechanism, and an evaporator. The refrigerant discharged from the compressor is condensed in the condenser, and then expanded in the expander. The expanded refrigerant evaporates in the evaporator and then uses the refrigerant cycle of the refrigerant sucked into the compressor to cool or air the room or purify the air.

The compressor, on the other hand, causes mechanical friction during operation and lubricates through the oil to protect the compressor from mechanical friction. And the oil in the compressor is circulated in the cycle together with the high temperature and high pressure refrigerant gas compressed in the compressor.

On the other hand, when oil is accumulated in the condenser, the evaporator and the piping of the cycle, the oil is deteriorated. If the return to the compressor is not smooth, the amount of oil in the compressor is insufficient. Therefore, in order to prevent such a phenomenon, an oil separator for separating oil from the high-temperature and high-pressure refrigerant gas is connected to the discharge pipe of the compressor to recover the oil to the compressor suction side. As a result, the amount of oil circulating in the cycle is reduced and the oil shortage of the compressor is prevented.

The compressor or oil separator is provided with an oil leveler or a sensor for measuring the level of the oil. When the oil level of the oil in the compressor or the oil separator falls below a predetermined level, The operation of the machine is stopped. The compressor or oil separator is then replenished with oil.

However, when the oil is additionally replenished, the amount of oil in the entire system is increased, and the oil remains in the heat exchanger and the system performance is deteriorated. In addition, when the oil and the refrigerant of the system are all removed, and then an appropriate amount of the oil and the refrigerant are added again, there is a problem that the space can not be cooled or heated in the space to be air-

An object of the present invention is to provide an air conditioner control method capable of maintaining the oil level of a compressor or an oil separator at an oil level higher than a predetermined oil level so that the operation of the air conditioner is stopped.

Another object of the present invention is to provide an air conditioner capable of continuously providing cooling or heating to a space to be air conditioned while maintaining the oil level of the compressor at an oil level higher than a predetermined oil level so that the operation of the air conditioner is stopped And a control method.

The problems of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

According to another aspect of the present invention, there is provided a control method for an air conditioner, comprising: a first oil level measurement step of measuring an oil level of a compressor or an oil separator; A first oil level judging step of judging whether or not the oil level is lower than a second level which is higher than a first level which is set to forcibly terminate the operation of the air conditioner; And a first capacity reduction operation step of operating the operating capacity of the air conditioner at a lower operating capacity than the current operating capacity.
An air conditioner according to an embodiment of the present invention includes: a compressor for compressing refrigerant; A condenser for condensing the refrigerant compressed in the compressor; An oil separator installed between the compressor and the condenser for separating the oil from the refrigerant discharged from the compressor and recovering the separated oil to the compressor; An expansion mechanism in which the refrigerant condensed in the condenser is expanded; A shell-and-tube evaporator having a shell through which the refrigerant expanded in the expansion mechanism passes, and a tube disposed inside the shell and through which the heating medium passes; And an oil leveler for sensing a current OE level among a plurality of oil levels set in the compressor or the oil separator, wherein the compressor adjusts the operation capacity of the compressor according to the oil level sensed by the oil leveler.

The details of other embodiments are included in the detailed description and drawings.

According to the control method of an air conditioner of the present invention, one or more of the following effects can be obtained.

First, the oil level of the compressor or oil separator can be maintained at an oil level higher than the level predefined to stop the operation of the air conditioner. Therefore, there is an advantage that the air conditioner is not stopped due to the oil shortage of the compressor or the oil separator, so that the air conditioner can continuously provide cooling or heating.

Second, the operation of maintaining the oil level of the compressor or oil separator at a predetermined level or more is performed. Thereby preventing an increase in costs that may occur by further injecting oil into the compressor or oil separator. And the efficiency of the heat exchanger, which may be caused by an increase in the amount of oil throughout the system, is prevented.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a configuration diagram showing a schematic configuration of an air conditioner of the present invention. FIG. Referring to FIG. 1, an air conditioner compressor, an oil separator, a condenser, a receiver, an expansion mechanism, and an evaporator of the present embodiment are included. The above-described configurations cool or heat indoor air while forming a cooling cycle or a heating cycle. The air conditioner of the present embodiment may be configured as an indoor unit and an outdoor unit separate type, or may be integrally formed. And further includes various air conditioners using a cooling cycle such as a chiller.

The compressor (10) compresses gaseous refrigerant into gaseous refrigerant of high temperature and high pressure, and imparts a circulation force to allow the refrigerant to circulate in the cooling cycle.

An oil separator may be installed integrally with the discharge side of the compressor 10 or the compressor 10 and the oil separator 20 is installed at the discharge side of the compressor 10 in this embodiment. The oil separator 20 separates the oil contained in the gaseous refrigerant at high temperature and high pressure discharged from the compressor 10 from the gaseous refrigerant at high temperature and high pressure.

On the other hand, a certain amount of oil is present in the oil separator 20, and the oil of the oil separator 20 is connected to the inside of the compressor 10 or the suction side pipe of the compressor 10 to supply oil to the compressor. That is, the oil separator 20 continuously supplies the oil to the compressor 10 in the presence of a certain amount of oil. Therefore, a sensor or oil leveler is installed in the oil separator 20 in various forms to sense the amount or level of the oil contained in the oil separator, so that the level of the oil in the oil separator 20 can be periodically measured have. Therefore, the control method of the air conditioner described later is performed according to the level of the measured oil.

In this embodiment, the oil level of the oil separator is measured to perform a control method of the air conditioner, which will be described later. Various types of sensors capable of sensing the amount of oil in the compressor are provided, A control method of the air conditioner to be described later may be performed.

The condenser 30 condenses the high-temperature and high-pressure refrigerant compressed in the compressor while exchanging heat with the other heat medium. As the condenser 30, various types of heat exchangers may be used.

The expansion mechanism (50) causes the refrigerant condensed in the condenser (30) to expand before being evaporated in the evaporator (60). As the expansion mechanism 50, various types of valves capable of adjusting the opening degree can be used. The expansion mechanism 50 in the present embodiment can be opened or closed so that the flow rate through the expansion mechanism 50 is minimized when the first capacity reduction operation step described later is performed. Accordingly, the amount of the refrigerant circulating in the cooling or heating cycle can be reduced, and the amount of the oil transferred to the evaporator 60 together with the refrigerant can be reduced. On the other hand, in the normal operation phase, which will be described later, the opening degree of the expansion mechanism 50 is returned to the original opening degree.

The receiver 40 receives the liquid refrigerant that has passed through the condenser 30 when the opening degree of the expansion mechanism 50 is reduced in the first capacity reduction operation step S13. That is, when the opening degree of the expansion mechanism 50 is reduced or closed in the first capacity reduction operation step S13, the liquid refrigerant passing through the condenser 30 can be stored.

Various types of heat exchangers may be used for the evaporator 60, but a cell and tube type heat exchanger is used in this embodiment. In other words, the refrigerant flows through the tube, and the heat medium that exchanges heat with the refrigerant may flow through the tube. In this embodiment, the heat medium that exchanges heat with the refrigerant exchanges heat with the refrigerant in the cell while flowing through the tube.

In other words, oil and liquid refrigerant flow into the evaporator 60, and the refrigerant evaporated by the heat exchange with the heating medium is discharged to the outside of the evaporator 60 and flows into the compressor 10. Between the evaporator 60 and the compressor 10, a pipe capable of recovering oil or refrigerant in the evaporator 60 by a compressor can be connected. When the operation capacity of the air conditioner is reduced and the opening degree of the expansion mechanism (40) is closed or decreased while performing the first capacity reduction operation step (S13), the oil in the evaporator (60) The oil level of the separator may be raised.

The air conditioner of the present embodiment includes a control unit for receiving the sensed oil level signal and controlling the operation capacity of the air conditioner accordingly. The other constitution of the air conditioner of this embodiment is the same as the other constitution of a general air conditioner, and a description thereof will be omitted.

2 is a flowchart showing a control method of the air conditioner of the first embodiment of the present invention. A control method of the air conditioner of the first embodiment of the present invention will be described with reference to Fig.

In the first oil level measurement step (S11), the oil level of the compressor (10) or the oil separator (20) is measured. In the first oil level determination step S12, it is determined whether the oil level measured in the first oil level measurement step S11 is lower than a second level higher than a first level, which is set so as to forcibly terminate the operation of the air conditioner. If the measured oil level is equal to or lower than the second level, the operation of the air conditioner is operated at a lower operating capacity than the current operating capacity.

If the operating capacity of the air conditioner is reduced, the discharge pressure of the compressor 10 is reduced and the flow rate of the refrigerant flowing decreases. Accordingly, the amount of oil discharged to the outside of the oil separator 20 together with the refrigerant in the oil separator 20 or the compressor 10 is reduced. As a result, the oil level in the oil separator 20 or the compressor 10 is increased.

On the other hand, the first capacity reduction operation step (S13) can reduce the opening degree of the expansion mechanism (50). The opening degree can be reduced or closed so that the flow rate through the expansion mechanism 50 is minimized. Accordingly, the amount of the refrigerant circulating in the cooling or heating cycle can be reduced, and the amount of the oil transferred to the evaporator 60 together with the refrigerant can be reduced. The oil present in the evaporator 60 may be recovered to the compressor 10 to increase the oil level of the compressor 10 or the oil separator 20 while the opening degree of the expansion mechanism 50 is reduced.

The second oil level measurement step (S14) measures the oil level of the oil separator or the compressor again after the first capacity reduction operation step (S13). In the second oil level determination step S15, it is determined whether the measured oil level exceeds the second level. When it is determined that the measured oil level does not exceed the second level, a second oil level measurement step (S14) and a second oil level determination step (S15) are performed while performing the first capacity reduction operation step (S13) ). When the measured oil level exceeds the second level, a normal operation step (S16) of operating the operating capacity of the air conditioner with the original operating capacity is performed.

When the opening degree of the expansion mechanism 50 is reduced in the first capacity reduction operation step S13, the opening degree of the expansion mechanism 50 is recovered to the original opening degree in the normal operation step S16.

Therefore, according to the control method of the air conditioner of the present embodiment, the oil level of the compressor 10 or the oil separator 20 is measured in multiple stages, and the operating capacity of the air conditioner is variably controlled accordingly. Therefore, the oil level can be maintained at the first level or higher, which is set to stop the operation of the air conditioner. Consequently, it is possible to prevent the operation of the air conditioner from being stopped due to the oil shortage. Further, it is also possible to prevent the oil separator 20 from being further charged with oil due to the lack of oil.

On the other hand, when the oil level exceeds the second level in the second oil level determination step S15, the normal operation step S16 is performed in the first capacity reduction operation step S13 for a predetermined period of time After the operation, the operation can be performed with the original operation capacity. Therefore, the oil level can be formed at a level higher than the predetermined level in the second level, and in the second oil level determination step (S15), the normal operation step S16 is performed immediately after the oil level exceeds the second level, The oil level is lowered to the second level or less, and the normal operation step S16 and the first operation amount reducing step are repeated to prevent frequent capacity change.

3 is a flowchart showing a control method of a second embodiment of the present invention. Referring to FIG. 2, the steps S11 to S16 of the control method of the air conditioner of the present embodiment are the same as those of the first embodiment, and a description thereof will be omitted.

In this embodiment, when it is determined that the measurement level does not exceed the second level in the second oil level determination step S15, the third oil level determination step S27 is performed. The third oil level determination step S27 determines whether the oil level measured in the second oil level measurement step S15 reaches a predetermined first level to stop the operation of the air conditioner.

When the measured oil level does not reach the first level and is located between the first level and the second level, a second oil level measurement step (S14) and a second oil level determination step (S15) are performed do. And, if the measured oil level is determined to be equal to or lower than the first level, the forced operation termination step (S28) of forcibly terminating the operation of the air conditioner is performed.

That is, in this embodiment, even if the first capacity reduction operation step S13 is performed, if the measured oil level does not increase but decreases, when the oil level reaches the first level, the air conditioner is forcibly terminated, It is possible to prevent breakage of the compressor or the like.

4 is a flowchart showing an operation method of the air conditioner of the third embodiment of the present invention. Referring to FIG. 3, the steps S11 to S16 of the control method of the air conditioner of the present embodiment are the same as those of the first embodiment, and a description thereof will be omitted.

If it is determined in the second oil level determination step S15 that the measurement level does not exceed the second level in the present embodiment, the third oil level determination step S37 is performed. The third oil level determining step S37 determines whether the oil level measured in the second oil level measuring step S15 is higher than the oil level measured in the first oil level measuring step S11.

That is, if it is determined in the second oil level determination step S15 that the oil level has not increased enough to exceed the second level in the present embodiment, the air conditioner is operated at a reduced capacity in the first capacity reduction operation step S13 It is determined whether or not the oil level is raised.

When it is determined that the oil level has risen in the third oil level judging step S37, the second oil level measuring step S14 and the second oil level measuring step S14 are performed while operating at the reduced capacity in the first capacity reducing operation step S13. The oil level determination step S15 is repeatedly performed. That is, the air conditioner operates the air conditioner with the reduced capacity in the first capacity reduction operation step (S13) until the measured oil level reaches the second level.

If it is determined in the third oil level determination step S37 that the oil level measured in the second oil level measurement step S15 is not higher than the oil level measured in the first oil level measurement step S11, The second operation amount reducing step (S38) for operating the air conditioner with the operation capacity smaller than the operation amount of the air conditioner in the capacity reduction operation step (S13) is performed. Then, the second oil level measurement step S14 and the second oil level determination step S15 are performed again.

That is, in the present embodiment, when the operating capacity of the air conditioner is reduced while performing the first capacity reducing operation (S13), if the oil level does not rise, the operating capacity of the air conditioner is reduced to the first capacity reducing operation step S13 ) Is repeated until the oil level exceeds the second level.

5 is a flowchart showing an operation method of an air conditioner of a fourth embodiment of the present invention. Referring to FIG. 4, the steps S11 to S14 of the control method of the air conditioner of the present embodiment are the same as those of the first embodiment, and a description thereof will be omitted.

In the second oil level determining step S45 of this embodiment, the oil level measured in the second oil level measuring step S14 is different from the oil level measured in the first oil level measuring step S11, unlike the first to third embodiments It is determined whether or not the oil level is increased. That is, it is determined whether the oil level is increased when the operation is performed with the operation capacity of the air conditioner reduced in the first capacity reduction operation step (S13).

When it is determined that the oil level has risen in the second oil level determination step S45, the third oil level determination step S46 is performed. The third oil level determination step S47 determines whether the oil level measured in the second oil level measurement step S14 exceeds the second level. When the measured oil level exceeds the second level, a normal operation step (S48) of operating the operating capacity of the air conditioner with the original capacity is performed. In addition, since it is determined that the oil level is increasing in the second oil level measurement step S45 even if the measured oil level does not exceed the second level, the second oil level measurement step S14, The process of step S45 is repeatedly performed.

If it is determined in the second oil level determination step S45 that the oil level has not risen, the second capacity reduction operation step S46 is performed. The second operating capacity reducing step S46 operates the air conditioner with the operating capacity less than the operating capacity after the first operating capacity reducing step S13 is performed. Then, the air conditioner is operated at a capacity capable of raising the oil level while the second oil level measuring step (S14) and the second oil level judging step (S45) are repeatedly performed.

6 is a flowchart showing an operation method of an air conditioner of a fifth embodiment of the present invention. Referring to FIG. 5, the steps S11 to S13 of the control method of the air conditioner of the present embodiment are the same as those of the first embodiment, and a description thereof will be omitted.

In the present embodiment, the operation capacity of the air conditioner is operated at the operation capacity less than the current operation capacity in the first capacity reduction operation step (S13). Then, the air conditioner is operated at the operation capacity reduced in the first capacity reduction operation step (S13) for a predetermined time.

If the operating capacity of the air conditioner is reduced, then the discharge pressure of the compressor is reduced and the refrigerant flow rate is decreased. Accordingly, the amount of oil discharged to the outside of the oil separator together with the refrigerant in the oil separator or the compressor is reduced. As a result, the oil level in the oil separator or the compressor is increased.

In the present embodiment, the operation is performed for a predetermined time with the reduced operating capacity in the first capacity reduction operation step (S13) to raise the oil level in the oil separator or the compressor, and then the normal operation step (S54). Therefore, the amount of oil in the oil separator or the compressor can be maintained at a certain level while performing a simple step as compared with the above embodiments.

Meanwhile, the control method of the air conditioner of the present embodiment continuously senses the oil level of the oil separator or the compressor during the operation of the air conditioner. When the oil level is equal to or lower than the second level while repeating the first oil level measurement step S11 and the first oil level determination step S12 after performing the normal operation step S54, (S13) is performed. Therefore, in the present embodiment, after the first capacity reduction operation step S13 is performed, the operation capacity of the air conditioner is reduced until the level of the oil reaches the second level without performing the additional oil level measurement .

7 is a flowchart showing an operation method of an air conditioner of a sixth embodiment of the present invention. Referring to FIG. 6, the steps S11 to S14 of the control method of the air conditioner of the present embodiment are the same as those of the first embodiment, and a description thereof will be omitted.

The second oil level determination step S65 of the present embodiment determines whether the oil measured in the second oil level measurement step S14 is abnormal to the third level higher than the second level. If the oil level is equal to or higher than the third level, a normal operation step (S66) is performed in which the operation capacity of the air conditioner is operated at the original operation capacity.

In other words, the second oil level determination step S65 in this embodiment returns to the normal operation when the measured oil level reaches the third level, which is higher than the second level, unlike the above embodiment. Accordingly, the oil level can be formed to be higher than the third level height higher than the second level, the normal operation step is performed immediately after the oil level exceeds the second level, and the oil level is again lower than the second level The normal operation step and the first operation amount reducing step are repeated to prevent frequent capacity change.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning and range of the claims and the equivalents thereof are included in the scope of the present invention Should be interpreted.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a schematic configuration of an air conditioner of the present invention; FIG.

2 is a flowchart showing a control method of a first embodiment of the present invention;

3 is a flowchart showing a control method of a second embodiment of the present invention;

4 is a flowchart showing a control method of a third embodiment of the present invention;

5 is a flowchart showing a control method of a fourth embodiment of the present invention;

6 is a flowchart showing a control method of a fifth embodiment of the present invention;

7 is a flowchart showing a control method of a sixth embodiment of the present invention;

Description of the Related Art

10: compressor 20: oil separator

30: condenser 40: receiver

50: expansion device 60: evaporator

Claims (14)

A first oil level measuring step of measuring an oil level of the compressor or the oil separator; A first oil level judging step of judging whether the oil level measured in the oil level measuring step is lower than a second level higher than a first level preset to forcibly stop the operation of the air conditioner; A first capacity reduction operation step of, when the measured oil level is equal to or less than a second level in the first oil level determination step, operating the operation capacity of the air conditioner at an operation capacity less than the current operation capacity; A second oil level measurement step of measuring an oil level of the oil separator after the first capacity reduction operation step; Determining whether the oil level measured in the second oil level measurement step is higher than the oil level measured in the first oil level measurement step; If it is determined that the oil level measured in the second oil level measurement step is not higher than the oil level measured in the first oil level measurement step, the operation capacity of the air conditioner is lower than the operation capacity of the first operation amount reduction operation step A second capacity reduction operation step of operating at a small operating capacity; When the oil level measured in the second oil level measuring step is determined to be higher than the oil level measured in the first oil level measuring step, the oil level measured in the second oil level measuring step is higher than the second level Determining whether the level is equal to or higher than a third level; A normal operation step of operating the operating capacity of the air conditioner at an original operating capacity when the oil level measured at the second oil level measuring step is greater than the third level; And controlling the operation of the air conditioner. delete The method according to claim 1, Wherein the first capacity reduction operation step reduces the opening degree of the expansion mechanism so that the amount of the refrigerant passing through the expansion mechanism is reduced and the normal operation step restores the opening degree of the expansion mechanism to the original opening degree . delete The method according to claim 1, Determining whether the oil level is equal to or less than the first level if the oil level measured in the second oil level measuring step is equal to or less than a second level; And A forced operation termination step of forcibly terminating the operation of the air conditioner when the oil level is lower than the first level in the third oil level determination step; And a control unit for controlling the air conditioner. delete delete delete delete delete delete delete delete A compressor for compressing the refrigerant; A condenser for condensing the refrigerant compressed in the compressor; An oil separator provided between the compressor and the condenser for separating the oil from the refrigerant discharged from the compressor and recovering the separated oil to the compressor; An expansion mechanism in which the refrigerant condensed in the condenser is expanded; A shell-and-tube evaporator having a shell through which the refrigerant expanded in the expansion mechanism passes, and a tube disposed inside the shell and through which the heating medium passes; An oil leveler for sensing a current oil level among a plurality of oil levels set in the compressor or the oil separator; A controller receiving a signal corresponding to the oil level sensed by the oil leveler and controlling the operation capacity of the air conditioner; Lt; / RTI > Wherein, And controls the air conditioner to operate at a lower operating capacity than the current operating capacity if the oil level detected by the oil leveler is lower than a second level higher than a predetermined first level so that the operation of the air conditioner is forcibly terminated, The control unit controls the air conditioner to operate at a lower operating capacity than the current operating capacity, and then measures the oil level. If it is determined that the measured oil level does not exceed the measured oil level before the operation capacity is controlled, The operation capacity of the engine is reduced to a certain degree, And controls the air conditioner to operate at an original operating capacity when the oil level detected by the oil leveler exceeds a third level higher than the second level.

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