Patent Publication Number: US-11378315-B2

Title: Air conditioner system including refrigerant cycle circuit for oil flow blocking

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2019-0014527, filed on Feb. 7, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
     BACKGROUND 
     Field 
     Apparatuses and methods consistent with the disclosure relate to an air conditioner system, and more particularly, to an air conditioner system capable of minimizing an amount in which oil used for preventing damage to a compressor flows entirely through a cycle circuit. 
     Description of the Related Art 
     In a general air conditioner system, oil is required to prevent damage to a compressor. However, it was often that the oil was mixed with a refrigerant to be discharged from the compressor and the refrigerant was discharged together with the oil. 
     In order to solve the problem, an oil separator has conventionally been installed near an outlet of the compressor to separate only oil from the refrigerant discharged from the compressor and collect the oil back. However, when an ambient temperature is low, the oil separator has significantly low efficiency in separating the refrigerant and the oil from each other, and thereby, the refrigerant circulates still together with a large amount of oil mixed therewith along a cycle circuit even after passing through the oil separator. 
     In particular, in an air conditioner system for a building, a factory, or the like, the refrigerant usually circulates through connecting pipes of 300 m or more. If the oil discharged from the compressor is mixed with the refrigerant even after passing through the oil separator, it will take a long time for the oil circulating together with the refrigerant to return back to the compressor through all the connecting pipes. 
     Consequently, it has been required to inject additional oil to prevent damage to the compressor. However, the additionally injected oil increases a thermal resistance and reduces energy efficiency by, for example, being applied onto a wall surface of a heat exchanger (evaporator) tube, which has a relatively low pressure. Also, the injection of the additional oil causes an increase in material costs. 
     SUMMARY 
     According to an embodiment of the disclosure, an air conditioner system includes: a compressor; a four-way valve configured to provide a refrigerant circulation path depending on an operation mode of the air conditioner system; a blocking valve disposed between the compressor and the four-way valve; a circulation line configured to provide a path for introducing a refrigerant discharged from the compressor back into the compressor, when the blocking valve is in a closed state; and a controller configured to control the blocking valve based on a pressure of the refrigerant discharged from the compressor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and/or other aspects of the disclosure will be more apparent by describing certain embodiments of the disclosure with reference to the accompanying drawings, in which: 
         FIG. 1  is a diagram illustrating a cycle circuit for an air conditioner system including a blocking valve according to an embodiment of the disclosure; 
         FIG. 2  is a diagram for explaining an example of a condition for controlling the blocking valve; 
         FIG. 3  is a diagram for explaining another example of a condition for controlling the blocking valve; 
         FIG. 4  illustrates an algorithm for explaining an operation of the air conditioner system for controlling the blocking valve according to an embodiment of the disclosure; 
         FIG. 5  is a diagram for explaining various examples in which the air conditioner system including the blocking valve performs protection controls; 
         FIG. 6  is a diagram illustrating a cycle circuit of the air conditioner system according to an embodiment of the disclosure in more detail; 
         FIG. 7  is a diagram for explaining an example of a cycle circuit for using a refrigerant blocked by the blocking valve to increase a temperature of a liquid separator; and 
         FIG. 8  is a diagram for explaining an example of a cycle circuit for using a refrigerant blocked by the blocking valve to increase a temperature of a heat exchanger. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure provides an air conditioner system capable of blocking a refrigerant discharged from a compressor not to immediately flow into a heat exchanger or an indoor unit, when the refrigerant discharged from the compressor contains a large amount of oil. 
     In addition, the disclosure provides an air conditioner system capable of blocking a refrigerant having passed through the compressor and an oil separator not to immediately flow into the heat exchanger or the indoor unit, when separation efficiency of the oil separator is not good. 
     Ultimately, the disclosure provides an air conditioner system capable of minimizing additional injection of the refrigerant and the resultant deterioration in energy efficiency through the above-described process. 
     Before specifically describing the disclosure, a method for demonstrating the specification and drawings will be described. 
     First of all, the terms used in the specification and the claims are general terms selected in consideration of the functions in the various embodiments of the disclosure. However, these terms may vary depending on intentions of those skilled in the art, legal or technical interpretation, emergence of new technologies, and the like. Also, there may be some terms arbitrarily selected by the applicant. These terms may be construed as meanings defined in the specification and, unless explicitly defined, may be construed based on the entire contents of the specification and the common technical knowledge in the art. 
     Also, the same reference numerals or symbols described in each of the drawings attached to the specification denote parts or elements that perform substantially the same functions. For convenience of description and understanding, different embodiments will be described using the same reference numerals or symbols. That is, although elements having the same reference numerals are all illustrated in a plurality of drawings, the plurality of drawings do not mean one embodiment. 
     Also, in the specification and the claims, terms including ordinal numbers such as “first” and “second” may be used to distinguish the elements from each other. These ordinals are used to distinguish identical or similar elements from each other, and the use of such ordinals should not be understood as limiting the meanings of the terms. For example, elements combined with such ordinal numbers should not be limited in their use order, arrangement order, or the like by the numbers. If necessary, the ordinal numbers may be used interchangeably with each other. 
     In the specification, the singular expression includes the plural expression unless the context clearly indicates otherwise. In the application, the term “include” or “comprise” indicates the presence of features, numbers, steps, operations, elements, parts, or combinations thereof written in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, parts, or combinations thereof. 
     In the embodiments of the disclosure, the term “module”, “unit”, “part”, or the like refers to an element that performs at least one function or operation. The element may be implemented with hardware, software, or a combination of hardware and software. In addition, a plurality of “modules”, “units”, “parts”, or the like may be integrated into at least one module or chip and implemented by at least one processor, excluding the case where each of the plurality of “modules”, “units”, “parts”, or the like should necessarily be implemented with individual specific hardware. 
     Also, in the embodiments of the disclosure, when any part is described as being connected to another part, this includes not only a direct connection but also an indirect connection through another medium. When a certain part includes a certain element, unless explicitly described otherwise, this means that another element may be additionally included, rather than excluding another element. 
     In the embodiments of the disclosure, the meaning of “at least one of configuration 1, configuration 2 or configuration 3” may include “only configuration 1”, “only configuration 2”, “only configuration 3”, “both configuration 1 and configuration 2”, “both configuration 2 and configuration 3”, “both configuration 1 and configuration 3”, or “all of configuration 1, configuration 2, and configuration 3”. 
       FIG. 1  is a diagram illustrating a cycle circuit for an air conditioner system  100  including a blocking valve according to an embodiment of the disclosure. The air conditioning system  100  is a system installed in any of the various places such as homes, buildings, and factories, to control a temperature in the facility. 
     Referring to  FIG. 1 , the air conditioner system  100  is connected to a plurality of indoor units  200  connected to cooling expansion valves  151 , and may include a compressor  110 , a four-way valve  120 , a controller  130 , a heat exchanger  140 , a heating expansion valve  150 , and a liquid separator  160 . In addition, the air conditioner system  100  may include pipe lines  10 ,  20 ,  30 ,  40 ,  50 , and  60 , each for connecting the above-described components to one another. 
     Meanwhile, although the air conditioner system  100  is illustrated through  FIG. 1  as a component separate from the cooling expansion valve  151  and the indoor units  200 , the cooling expansion valve  151  and the indoor units  200  may be implemented as part of the air conditioner system  100 . 
     The compressor  110  is a component for compressing a refrigerant, which is generally a gas. In order to prevent a situation in which a metal part or the like of the compressor  110  is damaged in the process of compressing the refrigerant, the compressor  110  may be enclosed with oil therein. 
     The four-way valve  120  is a component for controlling a refrigerant circulation path depending on an operation mode (cooling mode or heating mode) of the air conditioner system  100 . 
     As an example, when the air conditioner system  100  operates in the heating mode, the four-way valve  120  may set a refrigerant path such that the refrigerant discharged from the compressor  110  and introduced into the four-way valve  120  via the line  10  may circulate through the indoor unit  200  via the line  20  to the heat exchanger  140 , and then through the four-way valve  120  back via the line  30 , and finally through the liquid separator  160  via the line  40  to the compressor  110 . 
     When the air conditioner system  100  operates in the cooling mode in reverse, the four-way valve  120  may set a refrigerant path such that the refrigerant discharged from the compressor  110  and introduced into the four-way valve  120  via the line  10  may circulate through the heat exchanger  140  via the line  30  to the indoor unit  200 , and then through the four-way valve  120  back via the line  20 , and finally through the liquid separator  160  via the line  40  to the compressor  110 . 
     To do so, the four-way valve  120  may include separate valves and/or internal pipe lines therein. The above-described operations of the four-way valve  120  may be electronically controlled by the controller  130 . Specifically, when the controller  130  transmits a switching signal corresponding to the operation mode to the four-way valve  120 , the four-way valve  120  may control a refrigerant path based on the operation mode corresponding to the received switching signal. 
     The controller  130  may control overall operations of the air conditioner system  100 . Specifically, the controller  130  may electronically control each of the components included in the air conditioner system  100 . 
     To do so, the controller  130  may include a processor (not shown) including a circuit and/or at least one software module. The processor may include a random access memory (RAM) (not shown), a read only memory (ROM) (not shown), a central processing unit (CPU) (not shown), a graphic processing unit (GPU) (not shown), a system bus (not shown), and the like. 
     The controller  130  may be a single integrated control unit controlling all the components of the air conditioner system  100 , but refer to all or at least one of a plurality of control units connected to each other to control respective areas of the air conditioner system  100 . 
     The controller  130  may control the components for changing a state of the refrigerant, such as the compressor  110  and the heat exchanger  140 , but may also electronically control various valves, including the four-way valve  120 , installed in the respective lines. 
     The heat exchanger  140  is a component operating as an evaporator for the refrigerant in the heating mode and as a condenser for the refrigerant in the cooling mode. According to a change in a state of the refrigerant in the heat exchanger  140 , heat is exchanged by a fan  145  between air and the refrigerant passing through the heat exchanger  140 . 
     The heating expansion valve  150  is a component for expanding the refrigerant in the heating mode before the liquid-state refrigerant is evaporated. 
     The liquid separator  160  is a component for separating the liquid-state refrigerant that has not been vaporized after the refrigerant passes through the heat exchanger  140  or the indoor unit  200 , so as to only provide the gas-state refrigerant to the compressor  110 . To do so, the liquid separator  160  may be disposed between the four-way valve  120  and an inlet port of the compressor  110 . 
     The indoor unit  200  is a component for providing cool air in the cooling mode and warm air in the heating mode, and may evaporate the refrigerant in the cooling mode and condense the refrigerant in the heating mode. The indoor unit  200  may separately include a fan, a motor, and the like for circulating air for exchange between the refrigerant and the air. 
     Although the indoor unit  200  is illustrated in  FIG. 1  as being installed in only one block, the indoor unit  200  may, of course, include a plurality of indoor units by installing one or more indoor units on each floor or in each area according to the facility scale of the building/factory. If the facility with the air conditioner system  100  installed therein is a building or a factory on a certain-extent scale or greater, the refrigerant movement path may be several hundreds of meters or longer for the refrigerant discharged from the air conditioner system  100  to return back through the indoor unit  200 . 
     In addition, referring to  FIG. 1 , the air conditioner system  100  according to an embodiment of the disclosure may include a blocking valve  180 - 1  disposed between the compressor  110  and the four-way valve  120 . The air conditioner system  100  may also include a circulation line  60  for providing a (closed loop) path for introducing the refrigerant discharged from the compressor  110  back into the compressor  110 . 
     The blocking valve  180 - 1  may block the refrigerant discharged from the compressor  110  not to reach the four-way valve  120 , or may not do so. 
     The blocking valve  180 - 1  may be implemented as a solenoid valve to be electronically controlled, but is not limited thereto. 
     The controller  130  may control the blocking valve  180 - 1  based on a pressure of the refrigerant discharged from the compressor  110 . Meanwhile, the controller  130  may close the blocking valve  180 - 1 , once the air conditioner system  100  starts to operate. 
     The controller  130  may open the blocking valve  180 - 1 , when a temperature of the compressor  110  is higher than a saturation temperature corresponding to the pressure of the refrigerant having been discharged from the compressor  110  by a predetermined value or more. 
     The saturation temperature refers to a temperature at which the refrigerant transitions to a liquid-gas state at the corresponding pressure. When the temperature of the compressor  110  is higher than the saturation temperature corresponding to the pressure of the refrigerant having been discharged from the compressor  110  by the predetermined value or more, it may be considered that the refrigerant and oil are physically separated at least to a certain extent in the compressor  110 . Accordingly, the controller  130  may open the blocking valve  180 - 1  to transfer the refrigerant discharged from the compressor  110  to the four-way valve  120 . 
     In this regard, referring to  FIG. 2 , the controller  130  may identify a pressure of the refrigerant having been discharged from the compressor  110  using a pressure sensor  11 , and may identify a temperature of the compressor  110  using a temperature sensor  12 . In this case, the temperature sensor  12  may be installed on a surface of the compressor  110  to sense a temperature of the compressor  110 . 
     For example, the controller  130  may open the blocking valve  180 - 1 , when the temperature of the compressor  110  is 5° C. or more higher than the saturation temperature corresponding to the pressure of the refrigerant having been discharged from the compressor  110 . 
     However, this is merely an example. The type, location, and predetermined value of each sensor are not limited thereto. Especially, the predetermined value may be set differently depending on the material constituting the compressor  110 , the thickness of the compressor  110 , the thickness or properties of each pipe, and the like. 
     Meanwhile, referring to  FIG. 3 , the air conditioner system  100  may further include an oil separator  170  disposed between the compressor  110  and the four-way valve  120 . 
     The oil separator  170  is a component for separating oil from the refrigerant discharged from the compressor  110  to be supplied to the four-way valve  120 . The oil separated in the oil separator  170  may be introduced back into the compressor  110  via an oil return line  70 . 
     At this time, the controller  130  may open the blocking valve  180 - 1 , when a discharge temperature of the compressor  110  is higher than a saturation temperature corresponding to the pressure of the refrigerant having been discharged from the compressor  110  and having passed through the oil separator  170  by a predetermined value or more. 
     When a temperature of the refrigerant that is being discharged from the compressor  110 , that is, the discharge temperature, is higher than the saturation temperature corresponding to the pressure of the refrigerant having been discharged from the compressor  110  and having passed through the oil separator  170  by the predetermined value or more, it may be considered that the separation efficiency of the oil separator  170  is at a certain-extent level or higher, and thus, the controller  130  may open the blocking valve  180 - 1 . 
     In this regard, referring to  FIG. 3 , the controller  130  may identify the pressure of the refrigerant having been discharged from the compressor  110  (having passed through the oil separator  170 ) using the pressure sensor  11 , and may identify the discharge temperature of the compressor  110  using a temperature sensor  13 . In this case, the temperature sensor  13  may be installed on a surface of a pipe in which the refrigerant is being discharged from the compressor  110  flows so as to sense the discharge temperature of the compressor  110 . 
     For example, the controller  130  may open the blocking valve  180 - 1 , when the discharge temperature of the compressor  110  is 15° C. or more higher than the saturation temperature corresponding to the pressure of the refrigerant having been discharged from the compressor  110  (having passed through the oil separator  170 ). 
     However, this is merely an example. The type, location, and predetermined value of each sensor are not limited thereto. Especially, the predetermined value may be set differently depending on the material constituting the compressor  110 , the thickness of the compressor  110 , the thickness or properties of each pipe, and the like. 
       FIG. 4  illustrates an algorithm for explaining an operation of the air conditioner system  100  for controlling the blocking valve according to an embodiment of the disclosure. 
     Referring to  FIG. 4 , when the operation of the air conditioner system  100  is started (S 410 ), the controller  130  may first identify whether the air conditioner system  100  operates in a heating mode. 
     When the air conditioner system  100  does not operate in the heating mode (S 420 —N), the controller  130  may perform a normal operation while opening the blocking valve  180 - 1  (S 470 ). When the air conditioner system  100  operates is in the heating mode (S 420 —Y), however, the controller  130  may close the blocking valve  180 - 1  at the same time when the operation of the compressor  110  is started (S 430 ). In general, when an ambient temperature is low, it is highly likely that the refrigerant and the oil may be physically combined in the compressor  110 , or the efficiency of the oil separator  170  may be low. It is thus necessary to close the blocking valve  180 - 1  upon the start of the heating-mode operation in a low temperature environment. 
     Meanwhile, in the algorithm of  FIG. 4 , the blocking valve  180 - 1  is closed at the same time when the operation of the compressor  110  is started (S 430 ), but it may be sufficient if the blocking valve  180 - 1  is closed only within a predetermined time from the time when the operation of the compressor  110  is started. 
     In addition, in case that the four-way valve  120  includes valves for switching a refrigerant circulation path, and it is required to use a high-pressure environment, which is caused by the compressor  110  spouting the refrigerant, when switching the refrigerant circulation path to the heating-mode path, the step S 430  of  FIG. 4  may be slightly different. In this case, if the blocking valve  180 - 1  is closed at the same time when the operation of the compressor  110  is started, the four-way valve  120  may remain unable to switch the refrigerant path to be suitable for the heating mode. 
     In this case, the controller  130  may therefore close the blocking valve  180 - 1  after a predetermined time (e.g., 5 seconds) has elapsed since a switching signal for switching the four-way valve  120  to the heating mode is transmitted from the controller  130  to the four-way valve  120  even though the operation of the compressor  110  has already been started, rather than closing the blocking valve  180 - 1  at the same time when the operation of the compressor  110  is started. Specifically, the controller  130  may close the blocking valve  180 - 1  after a first predetermined time from the time when the switching signal is transmitted to the four-way valve  120  and within a second predetermined time from the time when the operation of the compressor  110  is started. 
     Referring back to the algorithm of  FIG. 4 , after closing the blocking valve  180 - 1  (S 430 ), the controller  130  may identify whether the temperature of the compressor  110  is 5° C. or more higher than the saturation temperature corresponding to the pressure of the refrigerant having been discharged from the compressor  110 . 
     Even if a difference between the temperature of the compressor  110  and the saturation temperature is smaller than 5° C. (S 440 —N), the temperature of the compressor  110  may increase over time due to the operation of the compressor  110 . 
     When the temperature of the compressor  110  is 5° C. or more higher than the saturation temperature (S 440 —Y), the controller  130  may identify whether the discharge temperature of the compressor  110  is 15° C. or more higher than the saturation temperature (S 450 ). Meanwhile, unlike  FIG. 4 , there may be only either step S 440  or step S 450 , or steps S 440  and S 450  may be changed in terms of order. 
     When the discharge temperature of the compressor  110  is 15° C. or more higher than the saturation temperature (S 450 —Y), the controller  130  may open the blocking valve  180 - 1  and perform a normal operation (S 470 ). At this time, the normal operation means that the refrigerant circulates a cycle circuit for the air conditioner system  100  and the indoor unit  200  depending on the operation mode without obstruction by the blocking valve  180 - 1 . 
     Meanwhile, when the blocking valve  180 - 1  is opened after being closed for a while as in the above-described embodiments, the controller  130  may additionally perform some protection controls to prevent a problem that may occur as the blocking valve  180 - 1  is closed. 
     In this regard,  FIG. 5  illustrates a cycle circuit for explaining various examples of the protection controls of the air conditioner system  100  including the blocking valve  180 - 1 . 
     Referring to  FIG. 5 , the controller  130  may open a valve  180 - 2  disposed in the circulation line  60 , when an amount of the oil in an oil return line  70  for supplying the oil discharged from the oil separator  170  to the inlet port of the compressor is smaller than a predetermined amount and a pressure at the inlet port of the compressor  110  is lower than a predetermined pressure. This is to prevent damage to the compressor  110  due to an insufficient amount of oil at the inlet port of the compressor  110 . 
     In this case, the amount of oil in the oil return line  70  may be identified by using an oil amount sensor (not shown) installed at an output of the oil separator  170  or an oil amount sensor (not shown) installed in the oil return line  70 . In addition, the pressure at the inlet port of the compressor  110  may be sensed by using a pressure sensor  51 . 
     As an example, the controller  130  may open the valve  180 - 2 , when the pressure at the inlet port of the compressor  110  is 2.0 kgf/cm 2  in a state in which the amount of oil in the oil return line  70  is insufficient. 
     The controller  130  may also open the blocking valve  180 - 1  when the pressure at the inlet port of the compressor  110  is higher than the predetermined pressure. This is also to prevent damage to the compressor  110  by preventing the pressure at the inlet port of the compressor  110  from being extremely high as a result of repeated situations in which the refrigerant blocked by the closing of the blocking valve  180 - 1  is returned to the inlet port of the compressor  110  through the circulation line  60 . 
     At this time, the pressure at the inlet port of the compressor  110  may be measured by the pressure sensor  51  of  FIG. 5  or the like. The predetermined pressure may be an allowable maximum pressure for the (low-pressure side) inlet port of the compressor  110  or a value that is smaller than the allowable maximum pressure by a predetermined value. 
     In addition, the controller  130  may lower an operating frequency of the compressor  110 , when a difference between the pressure of the refrigerant discharged from the compressor  110  and the pressure at the inlet port of the compressor  110  is greater than or equal to a predetermined value. At this time, the pressure of the (high-pressure side) refrigerant discharged from the compressor ( 110 ) may be measured by the pressure sensor  11 , and the pressure at the (low-pressure side) inlet port of the compressor  110  may be measured by the pressure sensor  51 . 
     This is a result of considering that the larger the difference in pressure between the high-pressure side and the low-pressure side, the greater the bypass noise due to the operation of the compressor  110 . As an example, when the difference between the high-pressure side and the low-pressure side is greater than or equal to a predetermined value (15 kgf/cm 2 ), the controller  130  may reduce noise by lowering the operating frequency of the compressor  110 . 
     The air conditioner system  100  necessarily needs to neither apply all of the three protection controls described above at the same time nor use only one of them. That is, the three protection controls described above may be each independently applied to the air conditioner system  100 . 
       FIG. 6  is a diagram illustrating a cycle circuit of the air conditioner system  100  according to an embodiment of the disclosure in more detail. 
     Referring to  FIG. 6 , the air conditioner system  100  may further include at least one of a pressure switch  14 , an intelligent power module (IPM)  135 , a double pipe heat exchanger  190 , or an expansion valve  195  for a double pipe heat exchanger, in addition to the above-described components. Also, the air conditioner system  100  may further include pipe lines  80  and  90  for connecting the pressure switch  14 , the intelligent power module (IPM)  135 , the double pipe heat exchanger  190 , and the expansion valve  195  for a double pipe heat exchanger to the heat exchanger  140 , the liquid separator  160 , and the indoor unit  200 . 
     The pressure switch  14 , which is a component for protecting the compressor  110  and the pipe line, is configured to lower a discharge pressure of the compressor  110  when the pressure is too high and increase the pressure when the pressure is too low. 
     The IPM  135 , which is a component for driving the compressor  110 , the fan  145 , and the like, may include an inverter for converting an electric signal. When the IPM  135  is disposed between the heat exchanger  140  and the indoor unit  200  as illustrated in  FIG. 6 , the IPM  135  may be cooled by the flowing refrigerant. 
     The double pipe heat exchanger  190  and the expansion valve  195  for a double pipe heat exchanger are components for various purposes, for example, increasing an amount of oil in the compressor  110  and energy efficiency, increasing an amount of heat exchanged between indoor air and refrigerant in the indoor unit  200  in the cooling mode, and preventing the refrigerant from being evaporated before reaching the indoor unit  200  in the cooling mode. 
     Specifically, the refrigerant is expanded after partially flowing into the expansion valve  195  for a double pipe heat exchanger via the pipe line  30  and a low-temperature refrigerant is obtained. The refrigerant flowing in the double pipe heat exchanger  190  via the pipe line  30  and the obtained low-temperature refrigerant flow via different pipes that are adjacent to but separate from each other. As a result, heat exchange may be performed therebetween. 
     Referring to  FIG. 6 , the air conditioner system  100  may further include a temperature sensor  31  for checking a condensed degree of the refrigerant and the like, and a temperature sensor  41  for calculating a superheat degree of the gas-state refrigerant sucked into the compressor  110 , temperature sensors  91  and  92  for identifying a degree of heat exchange in the double pipe heat exchanger  190  as a condition for controlling a refrigerant expanding degree of the expansion valve  195  for a double pipe heat exchanger, and the like as well. 
     In addition, the air conditioner system  100  may further include valves  180 - 3  and  180 - 4  for opening/closing the pipe lines  80  and  90 . 
     Meanwhile, in addition to the above-described embodiments, two additional embodiments for efficiently using the refrigerant blocked by the blocking valve  180 - 1  will be described with reference to  FIGS. 7 and 8 . 
       FIG. 7  is a diagram for explaining an example of a cycle circuit for using the refrigerant blocked by the blocking valve  180 - 1  to increase a temperature of the liquid separator  160 . 
     Referring to  FIG. 7 , the air conditioner system  100  may further include a first line  60 ′ connecting the circulation line  60  and the inlet port of the liquid separator  160 , while surrounding an external surface of the liquid separator  160 . 
     At this time, the controller  130  may increase the temperature of the liquid separator  160  by opening a valve  180 - 5  disposed in the first line  60 ′ in a state in which the blocking valve  180 - 1  is closed. As a result, an amount of the liquid-state refrigerant in the liquid separator  160  may be reduced. This may be helpful in preventing a situation in which the liquid separator  160  is filled with liquid refrigerant therein, and thus, the liquid refrigerant as well as oil and gas refrigerants is introduced into the compressor  110 . 
       FIG. 8  is a diagram for explaining an example of a cycle circuit for using the refrigerant blocked by the blocking valve  180 - 1  to increase a temperature of the heat exchanger  140 . 
     Referring to  FIG. 8 , the air conditioner system  100  may further include a second line  60 ″ connecting the circulation line  60  and the heat exchanger  140 . Specifically, the second line  60 ″ may be connected to an outlet of the heat exchanger  140  on the basis of the cycle in the cooling mode. 
     At this time, the controller  130  may open a valve  180 - 6  disposed in the second line  60 ″ in a state in which the blocking valve  180 - 1  is closed. As a result, in the heating mode, the refrigerant discharged from the compressor  110  may circulate to be returned to the inlet port of the compressor  110  through the heat exchanger  140  (via the four-way valve  120  and the liquid separator  160 ). 
     In this case, the temperature of the heat exchanger  140  is increased until an oil recovery rate of the compressor  110  is stabilized, thereby removing a residual frost of the heat exchanger  140 , and delaying impregnation of the heat exchanger  140  with oil therein after the blocking valve  180 - 1  is opened. 
     The air conditioner system according to the disclosure is capable of blocking the refrigerant having passed through the compressor (and the oil separator) not to immediately flow into the pipe connected to the heat exchanger or the indoor unit, when the refrigerant discharged from the compressor contains a large amount of oil and/or when the separation efficiency of the oil separator is not good. 
     As a result, the air conditioner system according to the disclosure may minimize additional injection of the refrigerant and the resultant deterioration in energy efficiency. 
     Meanwhile, the various embodiments described above may be implemented through a recording medium that is readable by a computer or a similar device by using software, hardware, or a combination thereof. 
     For hardware implementation, the embodiments described in the disclosure may be implemented using at least one of application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, micro-processors, or other electrical units for performing functions. 
     In some cases, the embodiments described in the specification may be implemented by a processor (not shown) itself. For software implementation, the embodiments, such as procedures and functions, described in the specification may be implemented by separate software modules. Each of the software modules may perform one or more functions or operations described in the specification. 
     Meanwhile, computer instructions for performing processing operations of the air conditioner system  100  according to the various embodiments of the disclosure described above may be stored in a non-transitory computer-readable recording medium. The computer instructions stored in the non-transitory computer-readable medium may cause a specific device to perform the processing operations of the air conditioner system  100  according to the various embodiments described above when executed by a processor of the specific device. 
     The non-transitory computer-readable medium refers to a medium that stores data semi-permanently, rather than storing data for a short time, such as a register, a cache, or a memory, and is readable by an apparatus. Specifically, the above-described various applications or programs may be stored and provided in a non-transitory computer-readable medium such as a compact disc (CD), a digital versatile disk (DVD), a hard disk, a Blu-ray disk, a universal serial bus (USB), a memory card, or a ROM. 
     In addition, although the preferable embodiments of the disclosure have been illustrated and described hereinabove, the disclosure is not limited to the specific embodiments as described above, and may be variously modified by those skilled in the art to which the disclosure pertains without departing from the gist of the disclosure as claimed in the appended claims. Such modifications should not be individually understood from the technical spirit or prospect of the disclosure.