KR20170111346A - Air Conditioner - Google Patents

Abstract

The air conditioner of the present invention comprises a compressor for compressing and discharging a refrigerant, a condenser for condensing the refrigerant compressed in the compressor, an expansion device for expanding the refrigerant condensed in the condenser, a refrigerant expanded in the expansion device is evaporated, A bypass unit for bypassing a part of the refrigerant discharged from the condenser to the discharge end of the evaporator, a part of the refrigerant discharged from the compressor, and a refrigerant discharged from the refrigerant before being sucked into the compressor And a control unit for controlling the overall operation of the air conditioner, wherein the control unit is configured to cause the bypass unit to cool the refrigerant discharged from the condenser to the discharge end of the evaporator during the oil recovery operation Pass control is performed.

Description

Air conditioner

The present invention relates to an air conditioner.

Generally, an air conditioner is a device for cooling indoor or certain space by using a refrigeration cycle including a compressor, a condenser, an expansion device, and an evaporator.

Such an air conditioner is used as a device for cooling a showcase configured to display refrigeration and refrigeration products. That is, the evaporator of the air conditioner is placed in a showcase, and the condenser is placed outdoors.

There is a need for the conventional air conditioner to prevent the depletion of the refrigerant oil in the compressor by properly recovering the refrigerant oil discharged from the compressor together with the refrigerant to ensure the reliability of the compressor.

Generally, the viscosity of the refrigeration oil itself used in the air conditioner becomes larger as the temperature becomes lower. In the evaporator used for the showcase, the temperature of the refrigerant is maintained at about -40 ° C to -5 ° C.

Therefore, the oil in the gas pipe connecting the suction end of the compressor at the discharge end of the evaporator becomes very high in viscosity and the fluidity is lowered. The refrigerating oil stays in the gas pipe and can not be recovered by the compressor, and the reliability of the compressor is lowered.

Further, the gas pipe between the evaporator and the compressor usually has a length of several tens to several hundred meters, and there is a problem that the length of the gas pipe is limited at the time of installation due to the refrigerating oil staying in the gas pipe.

Most of the freezing oil which can not be recovered by the compressor as shown in Fig. 10, stays in the gas pipe.

An object of the present invention is to provide an air conditioner in which the length of a gas pipe is increased to improve the degree of freedom of installation, the efficiency is improved, and the reliability of the compressor is improved.

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 an aspect of the present invention, there is provided an air conditioner comprising: a compressor for compressing and discharging refrigerant; a condenser for condensing the refrigerant compressed in the compressor; an expansion device for expanding the refrigerant condensed in the condenser; A bypass unit for bypassing a part of the refrigerant discharged from the condenser to the discharge end of the evaporator, a bypass unit for bypassing a part of the refrigerant discharged from the condenser to the discharge end of the evaporator, an evaporator for evaporating the refrigerant expanded in the expansion unit, A heat exchanging unit for exchanging a part of the refrigerant discharged from the compressor with the refrigerant before being sucked into the compressor, and a control unit for controlling the overall operation of the air conditioner, wherein in the oil recovery operation, And the refrigerant discharged from the evaporator is bypassed to the discharge end of the evaporator All.

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

The air conditioner of the present invention has one or more of the following effects.

First, the embodiment has an advantage that oil remaining in the gas pipe can be recovered quickly and quickly during normal operation.

Second, since the embodiment can quickly recover the oil remaining in the gas pipe, there is an advantage of improving the reliability of the compressor.

Third, since the amount of oil remaining in the gas pipe is reduced in the embodiment, there is an advantage that the length of the gas pipe can be increased, and the degree of freedom of installation of the air conditioner is increased.

Fourth, the embodiment has an advantage of preventing the compressor from being damaged during the oil recovery operation.

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.

1 is a schematic view of a refrigerant cycle circuit diagram of an air conditioner according to an embodiment of the present invention.
2 is a block diagram of an air conditioner according to an embodiment of the present invention.
3 is a view showing an accumulator according to an embodiment of the present invention.
4 is a perspective view of a showcase according to an embodiment of the present invention.
5 is a sectional view of the showcase shown in Fig.
6 is a view illustrating a flow of refrigerant during normal operation of the air conditioner according to an embodiment of the present invention.
7 is a view illustrating a refrigerant flow during an oil recovery operation of an air conditioner according to an embodiment of the present invention.
8 is a flowchart of a method of controlling an air conditioner according to an embodiment of the present invention.
9 is a flowchart of a method of controlling an air conditioner according to another embodiment of the present invention.
Fig. 10 is a graph showing the oil remaining amount according to each component of the air conditioner according to the comparative example. Fig.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with 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.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" Can be used to easily describe the correlation of components with other components. Spatially relative terms should be understood as terms that include different orientations of components during use or operation in addition to those shown in the drawings. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element . Thus, the exemplary term "below" can include both downward and upward directions. The components can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. &Quot; comprises "and / or" comprising ", as used herein, unless the recited component, step, and / or step does not exclude the presence or addition of one or more other elements, steps and / I never do that.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

In the drawings, the thickness and the size of each component are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size and area of each component do not entirely reflect actual size or area.

Hereinafter, the preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a refrigerant cycle circuit of an air conditioner according to an embodiment of the present invention, and FIG. 2 is a block diagram of an air conditioner according to an embodiment of the present invention.

1 and 2, an air conditioner 10 according to an embodiment of the present invention includes a compressor 210 for compressing and discharging a refrigerant, a condenser 240 for condensing the refrigerant compressed in the compressor 210, An expansion device 22 for expanding the refrigerant condensed in the condenser 240, an evaporator 160 for evaporating the refrigerant expanded in the expansion device 22 and performing heat exchange with the room air and discharging the evaporated refrigerant to the compressor 210 A bypass unit for bypassing a part of the refrigerant discharged from the condenser 240 to the discharge end of the evaporator 160, and a control unit 300 for controlling the overall operation of the air conditioner.

The air conditioner 10 of the embodiment includes an accumulator 260 for limiting the inflow of the liquid refrigerant into the refrigerant flowing into the compressor 210 and a refrigerant discharged from the compressor 210 to the compressor 210, And a heat exchange unit for exchanging heat with the refrigerant.

The air conditioner 10 includes an outdoor unit 200 disposed outdoors and an indoor unit 100 disposed inside the indoor unit 100. The indoor unit 100 and the outdoor unit 200 are connected to each other. The outdoor unit 200 includes a compressor 210, a condenser 240, and a heat exchange unit. The indoor unit 100 is provided with an evaporator 160 and an expansion device 22.

The compressor 210 is installed in the outdoor unit 200, compresses the introduced low-temperature and low-pressure refrigerant into high-temperature and high-pressure refrigerants, and discharges the refrigerant. Various types of compressor 210 may be used, including a reciprocating compressor 210 using a cylinder and a piston, a scroll compressor 210 using an orbiting scroll and a fixed scroll, an inverter compressor (210), and the like.

One or more compressors 210 may be provided according to the embodiment, and one compressor 210 is provided in the present embodiment.

The compressor 210 is connected to the evaporator 160 and the condenser 240. Specifically, the compressor 210 is configured such that the refrigerant vaporized in the evaporator 160 flows during normal operation (refrigeration operation), refrigerant bypassed in the oil recovery operation and refrigerant evaporated in the evaporator 160 are combined and introduced A port 211, and a discharge port 212 through which the compressed refrigerant is discharged to the condenser 240.

The compressor 210 is connected to the condenser 240 through a connection pipe 13 and is connected to the evaporator 160 and the gas pipe 12. The inlet port of the compressor 210 is connected to the gas pipe 12 and the discharge port 212 of the compressor 210 is connected to the connection pipe 13.

The connection pipe 13 is provided with an oil separator 220 for separating refrigerant discharged from the compressor 210 and oil in the oil and recovering the separated oil to the compressor 210.

The embodiment further includes an oil level sensor (230) sensing the degree of oil in the compressor (210). The oil level sensor 230 senses the oil level in the compressor 210 and provides oil level information to the control unit 300.

The condenser 240 is disposed in the outdoor unit 200 disposed in the outdoor space, and exchanges the refrigerant passing through the condenser 240 with outdoor air. The condenser 240 condenses the refrigerant during the cooling operation.

The condenser 240 is connected to the compressor 210, the expansion device 22 and the evaporator 160. The refrigerant compressed by the compressor 210 and passed through the discharge port 212 of the compressor 210 during the cooling operation flows into the condenser 240 and is condensed and flows to the expansion device 22.

The condenser 240 is connected to the evaporator 160 and the liquid pipe 11. The liquid pipe (11) is provided with an expansion device (22) for expanding the refrigerant. The expansion device 22 includes an electronic expansion valve or a thermostatic expansion valve. The expansion device 22 may be provided in the indoor unit 100 or the outdoor unit 200. The expansion device 22 is provided in the indoor unit 100 and the outdoor unit 200 and the indoor unit 100 are manufactured in separate manufacturers and are not communicated with each other. Preferably, the expansion device 22 includes a thermostatic expansion valve. The temperature expansion valve automatically adjusts the opening value according to the temperature of the refrigerant being measured. The expansion device (22) expands the refrigerant flowing in.

The evaporator 160 is disposed in the indoor unit 100 disposed in the indoor space, and exchanges the refrigerant that has passed through the evaporator 160 with the indoor air. The evaporator 160 evaporates the refrigerant during the cooling operation.

The evaporator 160 is connected to the condenser 240, the expansion device 22 and the compressor 210. During the cooling operation, the refrigerant expanded in the expansion device (22) flows into the evaporator (160), then evaporates and flows into the compressor (210). The evaporator 160 is connected to the compressor 210 by a gas pipe 12. The refrigerant evaporated in the evaporator 160 flows into the compressor 210 through the gas pipe 12.

The evaporator 160 may be provided in the indoor unit 100 as described above. The indoor unit 100 can be realized, for example, as a showcase that displays commodities and opens to the outside. The detailed structure of the showcase will be described later. The indoor unit 100 is provided with a showcase valve 210 for controlling the refrigerant flowing into the evaporator 160 from the condenser 240. The showcase valve 210 is disposed in the liquid pipe 11 to open and close to regulate the flow of the refrigerant.

The refrigerant evaporated in the evaporator 160 is sucked into the compressor 210, and the circulation cycle of the refrigerant is completed. The gas pipe (12) is provided with an accumulator (260) which restricts the flow of liquid refrigerant into the refrigerant flowing into the compressor (210).

The gas pipe 12 includes a first gas pipe 12-1 connecting the accumulator 260 and the evaporator 160 and a second gas pipe 12-2 connecting the accumulator 260 and the input port of the compressor 210 2 gas pipe 12-2.

The gas pipe (12) is provided with a discharge temperature sensor (25) for measuring the temperature of the refrigerant discharged from the evaporator (160). The discharge temperature sensor 25 provides temperature information to the control unit 300 in excess of the temperature of the refrigerant discharged from the evaporator 160. Preferably, the discharge temperature sensor 25 is disposed at a position adjacent to the evaporator 160 in the gas pipe 12. That is, the discharge temperature sensor 25 is disposed at a position adjacent to the evaporator 160 in the first gas pipe 12-1.

The bypass unit bypasses a part of the refrigerant discharged from the condenser 240 to the discharge end of the evaporator 160. In the oil recovery operation, the bypass unit supplies a part of the high-temperature and high-pressure refrigerant discharged from the condenser 240 to the gas pipe 12 as the discharge end of the evaporator 160 in the cooling operation (normal operation). The high-temperature, high-pressure refrigerant supplied to the gas pipe 12 by the bypass unit phase-changes the refrigerant into two phases in the gas pipe 12, and raises the temperature. The temperature of the oil in the gas pipe 12 is raised, the solubility is increased, and the viscosity is reduced. Therefore, the viscosity of the oil remaining in the gas pipe (12) with a large viscosity is reduced during normal operation, and is easily recovered to the compressor (210) by the pressure of the refrigerant. As a result, there is an effect that the reliability of the compressor 210 is improved.

The bypass unit includes a bypass pipe 31 connecting the liquid pipe 11 connecting the condenser 240 and the expansion device 22 and the gas pipe 12 connecting the evaporator 160 and the compressor 210, And an intermittent valve 32 disposed in the bypass piping 31 for regulating the flow of the refrigerant.

The bypass piping 31 bypasses part of the refrigerant condensed in the condenser 240 to the discharge end of the evaporator 160. One side of the bypass pipe 31 is connected to the liquid pipe 11 and the other side of the bypass pipe 31 is connected to the gas pipe 12.

In order to efficiently collect the stagnant oil in the gas pipe 12, the connecting position of the bypass pipe 31 is important. It is preferable that the bypass pipe 31 is connected to the gas pipe 12 at a position relatively close to the evaporator 160 among the compressor 210 and the evaporator 160. The bypass piping 31 is connected to the gas pipe 12 at a position adjacent to the evaporator 160. Specifically, the other side of the bypass pipe 31 is connected to the first gas pipe 12-1.

The intermittent valve 32 regulates the flow of the refrigerant flowing through the bypass pipe 31. The intermittent valve 32 includes a solenoid valve or an electronic expansion valve. Preferably, the intermittent valve 32 includes an electronic expansion valve whose various opening values are adjusted. The valve opening degree of the intermittent valve 32 is adjusted by the control signal of the control unit 300. The opening value of the intermittent valve 32 is adjusted so that the air conditioner of the embodiment can perform the oil recovery operation during the cooling operation (normal operation), stop the cooling operation, and perform only the oil recovery operation.

The refrigerant flowing into the bypass piping (31) converts the refrigerant in the gas pipe (12) into two phases. Accordingly, the two-phase refrigerant in the gas pipe 12 flows into the accumulator 260 to accelerate the accumulation of the liquid phase refrigerant in the accumulator 260, thereby discharging the accumulator 260 from the accumulator 260 to the compressor 210 The liquid is contained in the refrigerant, which causes damage to the compressor 210.

In order to prevent the compressor 210 from being damaged, the heat exchanging unit of the embodiment exchanges a part of the refrigerant discharged from the compressor 210 with the refrigerant before being sucked into the compressor 210 to prevent the compressor 210 from being damaged .

The heat exchange unit includes a heat exchanging unit 253 for exchanging heat between a part of the refrigerant discharged from the compressor 210 and the refrigerant stored in the accumulator 260 and a control unit for controlling the flow of the refrigerant supplied to the heat exchanging unit 253 A valve 252 and a hot gas pipe 251 connecting the heat exchanging unit 253 and the liquid pipe 11. [

The hot gas piping 251 supplies a part of the refrigerant discharged from the compressor 210 to the heat exchanging part 253. The hot gas piping 251 recovers the refrigerant heat-exchanged in the heat exchanging part 253 to the liquid pipe 11. Specifically, the hot gas piping 251 includes a first hot gas piping 251 and a second hot gas piping 251.

The first hot gas piping 251 connects the connection pipe 13 and one side of the heat exchanging unit 253 to supply the high temperature and high pressure refrigerant to the heat exchanging unit 253. The second hot gas pipe 251 connects the liquid pipe 11 and the other side of the heat exchanging unit 253 to recover the refrigerant heat-exchanged in the heat exchanging unit 253 to the liquid pipe 11

The heat exchanging unit 253 exchanges heat between a part of the refrigerant discharged from the compressor 210 and the refrigerant stored in the accumulator 260. The heat exchanger 253 supplies heat to the accumulator 260 to limit the accumulation of the liquid phase and to prevent the liquid phase from being supplied to the compressor 210. It is preferable that the refrigerant in the heat exchanging part 253 performs heat exchange in an indirect heat transfer mode that is not mixed with the refrigerant in the accumulator 260.

3, the accumulator 260 is disposed inside the heat exchanger 253 through which the refrigerant compressed by the compressor 210 flows during the oil recovery operation. That is, the heat exchanger 253 is disposed in a coil shape surrounding the outer surface of the accumulator 260. The accumulator 260 is connected to the first gas pipe 12-1 through which the refrigerant evaporated in the evaporator 160 and the refrigerant bypassed from the evaporator 160 are combined and introduced into the accumulator 260 and the refrigerant discharged from the accumulator 260 The second gas pipe 12-2 is connected to the second gas pipe 12-2.

The regulating valve 252 regulates the flow of the refrigerant supplied to the heat exchanging part 253. A regulating valve 252 is disposed in the first hot gas line 251 to regulate the flow of refrigerant compressed in the compressor 210. The regulating valve 252 may comprise a solenoid valve or an electronic expansion valve. The regulating valve 252 is closed during normal operation and open during the oil recovery operation.

The control unit 300 controls the overall operation of the air conditioner. The control unit 300 may be configured with a logical breakable processing device, a memory, and the like.

The control unit 300 controls the air conditioner to a normal operation or an oil recovery operation state based on various kinds of information sensed by the air conditioner. The control unit 300 can perform the normal operation at the time of the oil recovery operation or can stop the normal operation.

The control unit 300 determines that the oil in the compressor 210 is insufficient, and starts the oil recovery operation. More specifically, the control unit 300 executes the oil recovery operation when the oil level inputted from the oil level sensor 230 is lower than the reference oil level, and the control unit 300 performs the oil recovery operation When the oil level is higher than the reference oil level, the normal operation is executed.

The control unit 300 can determine that the temperature of the gas pipe 12 is low and start the oil recovery operation. When the discharge temperature value input from the discharge temperature sensor 25 is lower than the reference discharge temperature value, the control unit 300 executes the oil recovery operation, and when the discharge temperature value inputted from the discharge temperature sensor 25 reaches the reference discharge temperature Value, the normal operation is executed.

The control unit 300 controls the bypass unit to bypass the refrigerant discharged from the condenser 240 to the discharge end of the evaporator 160 during the oil recovery operation. Here, the discharge end of the evaporator 160 means a position adjacent to the evaporator 160 in the gas pipe 12.

Specifically, the control unit 300 drives the compressor 210 during normal operation to supply cool air to the showcase. The control unit 300 drives the compressor 210 and opens the intermittent valve 32 to supply the gas pipe 12 with high temperature and high pressure refrigerant during the oil recovery operation. The control unit 300 can adjust the opening value and the opening time of the intermittent valve 32 during the oil recovery operation. The control unit 300 may open the showcase valve 210 to supply the refrigerant to the evaporator 160 or to close the showcase valve 210 and not to supply the refrigerant to the evaporator 160 during the oil recovery operation .

The control unit 300 controls the heat exchange unit to heat-exchange the refrigerant discharged from the compressor 210 and the refrigerant before being drawn into the compressor 210 during the oil recovery operation. Specifically, the control unit 300 opens the control valve 252 during the oil recovery operation to heat-exchange the high-temperature and high-pressure refrigerant discharged from the compressor 210 with the accumulator 260.

Hereinafter, the structure of one embodiment of the showcase will be described with reference to Figs. 4 and 5. Fig.

The showcase according to an embodiment of the present invention includes a case 100 formed with a storage chamber 110 in which an article is stored and having a front surface opened and an upper surface discharge port 110 formed at a front surface of the upper surface of the case 100 to discharge cool air downward. A plurality of shelves 111 disposed inside the case 100 and on which the articles are placed and at least one shelf 111 of the plurality of shelves 111, And a lathe fan 189 for sucking the cool air discharged in the lower side.

The case 100 is formed in an approximate hexahedron shape having a front surface opened to form a storage chamber 110. [ The case 100 includes an outer case 101 forming an outer appearance and an inner case 103 disposed inside the outer case 101 to form a storage room 110. The storage chamber 110 is formed in an approximate hexahedron shape with its front surface opened.

The outer case 101 forms an outer appearance. The outer case 101 is preferably formed in an approximate hexahedron shape in which a part of the front face is opened. According to the embodiment, the outer case 101 may be partially opened at the side.

The inner case 103 is disposed inside the outer case 101. The inner case 103 is formed in an approximate hexahedron whose front surface is opened similarly to the outer case 101. According to the embodiment, the inner case 103 may be partially opened at the side surface thereof. The inner case 103 forms a storage room 110 in which an article is stored. Cool air for cooling or freezing the article stored in the storage compartment 110 flows between the outer case 101 and the inner case 103 and inside the inner case 103.

A plurality of shelves 111 are disposed in the storage room 110 inside the inner case 103. Various items are seated on the upper surface of the shelf 111. The shelf 111 is fixed to the rear surface of the inner case 103. The shelf 111 is formed in a horizontal direction toward the opened front side of the inner case 103. The plurality of shelves 111 are arranged in a vertical direction (vertical direction) to divide the storage chamber 110 up and down.

On the rear surface of the inner case 103, a plurality of rear discharge ports 123 through which cool air is discharged are formed. The plurality of rear-side discharge openings 123 are vertically or laterally spaced. The plurality of rear discharge ports 123 are preferably disposed between the plurality of shelves 111, respectively. The plurality of rear discharge openings 123 heat-exchange with the refrigerant in the evaporator 160 to be described later and discharge the cooled cold air forward. The plurality of rear discharge ports 123 formed on the rear surface of the inner case 103 discharge the chilled air to the open front of the inner case 103. The chilled air discharged from the plurality of rear discharge ports 123 flows along the horizontal direction of the shelf and refrigerates or cools the products placed on each of the plurality of shelves 111.

The upper surface of the inner case 103 is provided with an upper surface discharge port 121 through which cool air is discharged. The upper surface discharge port 121 is formed to be laterally long in the front surface of the upper surface of the inner case 103. The upper surface discharge port 121 is preferably disposed forward of the front ends of the plurality of shelves 111 without the shelf fans 189.

The upper surface discharge port 121 discharges cooled cool air, which is heat-exchanged with the coolant in an evaporator 160 to be described later, downward. The cool air discharged from the upper surface discharge port 121 is accelerated by the shelf fan 189, and then sucked into the cool air intake port 130 to be described later.

The upper surface discharge port 121 allows the discharged cold air to flow downward along the front surface of the storage chamber 110. The cool air discharged from the upper surface discharge port 121 serves as an air curtain for preventing external air from flowing into the storage chamber 110. The cool air discharged from the upper surface discharge port 121 flows in a vertical direction, and it can flow obliquely at an acute angle with respect to the vertical direction according to the embodiment.

The shelf fan 189 is disposed at the front end of at least one shelf 111 of the plurality of shelves 111. The shelf fan 189 is preferably disposed on a shelf 111 disposed in the middle of the plurality of shelves 111. When a plurality of shelf fans 189 are provided according to the embodiment, it is preferable that a plurality of shelf fans 189 are disposed at equal intervals between the upper surface discharge port 121 and the cold air inlet 130.

The lathe fan 189 sucks the cool air discharged from the upper surface discharge port 121 and discharges it to the lower side. The shelf fan 189 is preferably a sirocco fan which is formed long in the left-right direction. The rack fan 189 accelerates and discharges the cool air discharged from the upper surface discharge port 121 to the lower side and the cool air discharged from the shelf fan 189 is sucked into the cool air suction port 130.

The shelf fans 189 are disposed so as to protrude from the front ends of the plurality of shelves 111 on which the shelf fans 189 are not disposed. The shelf fan 189 is preferably disposed below the upper surface discharge port 121. The shelf fan 189 is preferably disposed on a line connecting the upper surface discharge port 121 and the cold air suction port 130.

The shelf fan 189 is supported by the shelf fan housing 180. The shelf fan housing 180 is formed at the front end of the shelf 111 where the shelf fan 189 is disposed. The shelf fan housing 180 is integrally formed with or separately formed from the shelf 111 in which the shelf fan 189 is disposed and is coupled to the shelf 111. [ The shelf fan housing 180 is protruded from the front ends of the plurality of shelves 111 on which the shelf fans 189 are not disposed.

On the upper side of the shelf fan housing 180, a shelf intake port 181 for sucking cool air discharged from the upper surface discharge port 121 is formed. The shelf suction port 181 is preferably disposed below the upper surface discharge port 121. A shelf discharge port 182 for discharging cool air sucked into the shelf suction port 181 is formed below the shelf fan housing 180. The shelf outlet 182 discharges cool air to the lower side. The shelf outlet 182 is preferably disposed above the cold air inlet 130.

A shelf fan 189 is provided inside the shelf fan housing 180. The shelf fan housing 180 rotatably supports the shelf fan 189. Inside the shelf fan housing 180, a shelf fan motor 188 for rotating the shelf fan 189 is provided.

A cool air inlet (130) through which cool air is sucked is formed on the bottom surface of the inner case (103). It is preferable that the cold air inlet 130 is formed to be long in the lateral direction on the bottom surface of the inner case 103. The cold air inlet 130 is preferably disposed below the shelf fan 189. The cold air inlet 130 is preferably disposed below the shelf outlet 182 of the shelf fan housing 180.

The cool air intake port 130 is discharged from the upper surface discharge port 121, sucked into the shelf suction port 181 by the shelf fan 189, and then sucked cool air discharged to the shelf discharge port 182. The cool air intake port 130 sucks the cool air discharged from the plurality of rear surface discharge ports 123. The cold air sucked into the cold air inlet 130 flows into the lower flow path 141 formed on the lower side of the inner case 103.

The lower flow path 141 is formed on the lower side of the bottom surface of the inner case 103. The lower flow path 141 is formed between the bottom surface of the inner case 103 and the bottom surface of the outer case 101. The lower flow path 141 communicates with the cold air inlet 130. A ventilation fan 150 is provided in the lower flow path 141.

The blowing fan 150 is disposed inside the lower flow path 141 formed below the bottom surface of the inner case 103. The air blowing fan 150 is rotatably disposed between the bottom surface of the inner case 103 and the bottom surface of the outer case 101. The blowing fan 150 forms a flow of cool air so that the cool air is sucked into the cool air inlet 130. The blowing fan 150 forms a flow of cool air so that cool air is discharged to the rear discharge port 123 and the upper discharge port 121.

The lower flow path 141 is connected to the rear flow path 143. The rear flow path 143 is formed between the rear surface of the inner case 103 and the rear surface of the outer case 101. The cold air drawn into the cold air inlet 130 and flowing into the lower flow path 141 is raised along the rear flow path 143 by the blowing fan 150.

The rear flow path 143 communicates with the plurality of rear discharge ports 123. The cool air flowing through the rear flow path 143 is distributed and discharged to each of the plurality of rear discharge ports 123.

An evaporator 160 for cooling the cold air is disposed in the rear flow path 143. The refrigerant in the evaporator 160 flows through the evaporator 160 and the refrigerant in the evaporator 160 undergoes heat exchange with the cold air flowing in the rear flow path 143. The refrigerant compressed in the compressor 210, condensed in the condenser 240, and expanded in the expansion device 22 is heat-exchanged with the cold air in the evaporator 160 and evaporated. The refrigerant flowing through the evaporator 160 receives heat from the cold air and evaporates, and the cold air is cooled.

The rear flow path 143 is connected to the upper flow path 145. The upper flow path 145 is formed on the upper surface of the inner case 103. The upper flow path 145 is formed between the upper surface of the inner case 103 and the upper surface of the outer case 101. The upper flow path 145 communicates with the upper surface discharge port 121. The cool air that has flowed to the upper flow path 145 through the rear flow path 143 is discharged through the upper surface discharge port 121.

The operation of the showcase according to the present invention will be described as follows

When the blowing fan 150 is driven, the cool air in the storage chamber 110 is sucked into the lower flow path 141 through the cool air intake port 130. The cool air that has flowed to the lower flow path 141 rises along the rear flow path 143 by the blowing fan 150.

The cool air that has flowed into the rear flow path 143 is heat-exchanged in the evaporator 160 and cooled. The cool air cooled in the evaporator 160 rises along the rear flow path 143 and a part thereof is discharged through the plurality of rear discharge ports 123. The chilled air discharged from the plurality of rear discharge ports 123 flows along the horizontal direction of the shelf and refrigerates or cools the products placed on each of the plurality of shelves 111. The cool air discharged from the plurality of rear discharge ports 123 and flowing along each of the plurality of shelves 111 flows downward and sucked into the cool air inlet 130.

The cool air that has risen through the rear flow path 143 and has flowed into the upper flow path 145 is discharged through the upper surface discharge port 121. The cool air discharged from the upper surface discharge port 121 is sucked into the shelf suction port 181 of the shelf fan housing 180 and discharged to the shelf discharge port 182. [ The cool air discharged from the upper surface discharge port 121 is accelerated by the shelf fan 189 to be discharged to the shelf discharge port 182 and then sucked into the cool air suction port 130.

The cool air discharged through the upper surface discharge port 121, accelerated by the shelf fan 189, and then sucked into the cool air inlet 130 forms an air curtain on the front surface of the storage compartment 110. The air curtain formed by the cool air blocks the outside air from flowing into the storage room 110. In addition, the cooling air discharged to the plurality of rear discharge ports 123 is prevented from flowing out of the storage chamber 110.

The operation of the air conditioner according to the present invention will now be described.

6 is a view illustrating a flow of refrigerant during normal operation of the air conditioner according to an embodiment of the present invention.

Hereinafter, operation of the air conditioner 100 in normal operation (cooling operation) according to an embodiment of the present invention will be described with reference to FIG.

The refrigerant compressed in the compressor 210 is discharged from the discharge port 212 and flows to the connection pipe 13. The refrigerant discharged from the discharge port 212 and flowing into the connection pipe 13 flows to the condenser 240. At this time, the control valve 252 is closed and the refrigerant compressed in the compressor 210 is restricted from flowing to the heat exchanging part 253.

The refrigerant flowing from the connection pipe 13 to the condenser 240 undergoes heat exchange with the outdoor air in the condenser 240 and is condensed. The refrigerant condensed in the condenser 240 flows to the expansion device 22 via the liquid pipe 11. The expansion device (22) expands the refrigerant flowing in. The expansion device 22 automatically adjusts its opening value according to the temperature value.

The refrigerant that has flowed into the expansion device 22 is expanded and flows to the evaporator 160. The refrigerant flowing into the evaporator 160 is evaporated by heat exchange with the indoor air in the evaporator 160. And cools the showcase while exchanging heat with the air-cooled air in the evaporator (160).

The refrigerant evaporated in the evaporator 160 flows into the gas pipe 12. The refrigerant flowing into the gas pipe (12) flows into the compressor (210) through the accumulator (260).

7 is a view illustrating a refrigerant flow during an oil recovery operation of an air conditioner according to an embodiment of the present invention.

Hereinafter, the operation of the air conditioner 100 according to the embodiment of the present invention in the oil recovery operation will be described with reference to FIG.

The refrigerant compressed in the compressor 210 is discharged from the discharge port 212 and flows to the connection pipe 13. A part of the refrigerant discharged from the discharge port 212 and flowing to the connection pipe 13 flows to the condenser 240. Another part of the refrigerant discharged from the discharge port 212 and flowing to the connection pipe 13 is opened to the control valve 252 and flows to the heat exchanging part 253. The refrigerant flowing into the heat exchanging part 253 is heat-exchanged with the refrigerant of the accumulator 260 to reduce the accumulation of the liquid phase refrigerant in the accumulator 260.

The refrigerant flowing from the connection pipe 13 to the condenser 240 undergoes heat exchange with the outdoor air in the condenser 240 and is condensed. The refrigerant condensed in the condenser 240 flows to the liquid pipe 11. A portion of the refrigerant that has flowed from the condenser 240 to the liquid pipe 11 flows into the expansion device 22. The expansion device (22) expands the refrigerant flowing in. The expansion device 22 automatically adjusts its opening value according to the temperature value. The refrigerant that has flowed into the expansion device 22 is expanded and flows to the evaporator 160. The refrigerant flowing into the evaporator 160 is evaporated by heat exchange with the indoor air in the evaporator 160. And cools the showcase while exchanging heat with the air-cooled air in the evaporator (160).

Another part of the refrigerant flowing from the condenser 240 to the liquid pipe 11 is opened to the bypass pipe 31 by the intermittent valve 32 and flows into the gas pipe 12 adjacent to the evaporator 160. The refrigerant introduced through the bypass piping 31 raises the temperature of the gas pipe 12 and changes the refrigerant in the gas pipe 12 into two phases to lower the viscosity of the oil in the gas pipe 12 and increase the fluidity.

The refrigerant evaporated in the evaporator 160 and the refrigerant bypassed by the bypass piping 31 flow into the gas pipe 12. The refrigerant flowing into the gas pipe (12) flows into the compressor (210) through the accumulator (260). The refrigerant in the accumulator 260 exchanges heat with the heat exchanging part 253 as described above.

8 is a flowchart of a method of controlling an air conditioner according to an embodiment of the present invention.

Referring to FIG. 8, in the method of controlling the air conditioner according to an embodiment of the present invention, when the oil in the compressor 210 is insufficient, it is determined that the oil recovery operation is performed and the oil recovery operation is started.

Specifically, the control unit 300 compares the oil level input from the oil level sensor 230 with the reference oil level to determine whether the oil recovery operation or the normal operation is performed (S10).

The control unit 300 executes the oil recovery operation when the oil level input from the oil level sensor 230 is lower than the reference oil level When the oil level is higher than the reference oil level, the normal operation is executed (S30).

The control unit 300 controls the bypass unit to bypass the refrigerant discharged from the condenser 240 to the discharge end of the evaporator 160 during the oil recovery operation. The control unit 300 drives the compressor 210 and opens the intermittent valve 32 to supply refrigerant of high temperature and high pressure to the gas pipe 12 during the oil recovery operation (S21). The control unit 300 can adjust the opening value and the opening time of the intermittent valve 32 during the oil recovery operation. The control unit 300 may open the showcase valve 210 to supply the refrigerant to the evaporator 160 or to close the showcase valve 210 and not to supply the refrigerant to the evaporator 160 during the oil recovery operation .

The control unit 300 controls the heat exchange unit to heat-exchange the refrigerant discharged from the compressor 210 and the refrigerant before being drawn into the compressor 210 during the oil recovery operation. Specifically, the control unit 300 opens the control valve 252 during the oil recovery operation to heat exchange the high-temperature and high-pressure refrigerant discharged from the compressor 210 with the accumulator 260 (S22).

The control unit 300 controls the bypass unit not to bypass the refrigerant discharged from the condenser 240 to the discharge end of the evaporator 160 during normal operation. The control unit 300 drives the compressor 210, closes the intermittent valve 32 (S31), opens the showcase valve 210, and supplies the refrigerant to the evaporator 160 during normal operation.

The control unit 300 controls the heat exchange unit to prevent heat exchange between the refrigerant discharged from the compressor 210 and the refrigerant before being sucked into the compressor 210 during normal operation. Specifically, the control unit 300 closes the control valve 252 during normal operation (S32).

9 is a flowchart of a method of controlling an air conditioner according to another embodiment of the present invention.

Referring to FIG. 9, in the control method of the air conditioner according to the embodiment of the present invention, when the temperature of the gas pipe 12 is low, it is determined that the oil recovery operation is performed and the oil recovery operation can be started.

Specifically, the control unit 300 compares the discharge temperature value inputted from the discharge temperature sensor 25 with the reference discharge temperature to judge whether the oil recovery operation or the normal operation is executed (S40).

The control unit 300 executes the oil recovery operation when the discharge temperature value inputted from the discharge temperature sensor 25 is lower than the reference discharge temperature value and the control unit 300 executes the oil recovery operation from the discharge temperature sensor 25 When the input discharge temperature value is higher than the reference discharge temperature value, the normal operation is executed (S30).

The control unit 300 controls the bypass unit to bypass the refrigerant discharged from the condenser 240 to the discharge end of the evaporator 160 during the oil recovery operation. The control unit 300 drives the compressor 210 and opens the intermittent valve 32 to supply refrigerant of high temperature and high pressure to the gas pipe 12 during the oil recovery operation (S21). The control unit 300 can adjust the opening value and the opening time of the intermittent valve 32 during the oil recovery operation. The control unit 300 may open the showcase valve 210 to supply the refrigerant to the evaporator 160 or to close the showcase valve 210 and not to supply the refrigerant to the evaporator 160 during the oil recovery operation .

The control unit 300 controls the heat exchange unit to heat-exchange the refrigerant discharged from the compressor 210 and the refrigerant before being drawn into the compressor 210 during the oil recovery operation. Specifically, the control unit 300 opens the control valve 252 during the oil recovery operation to heat exchange the high-temperature and high-pressure refrigerant discharged from the compressor 210 with the accumulator 260 (S22).

The control unit 300 controls the bypass unit not to bypass the refrigerant discharged from the condenser 240 to the discharge end of the evaporator 160 during normal operation. The control unit 300 drives the compressor 210, closes the intermittent valve 32 (S31), opens the showcase valve 210, and supplies the refrigerant to the evaporator 160 during normal operation.

The control unit 300 controls the heat exchange unit to prevent heat exchange between the refrigerant discharged from the compressor 210 and the refrigerant before being sucked into the compressor 210 during normal operation. Specifically, the control unit 300 closes the control valve 252 during normal operation (S32).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It should be understood that various modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

Claims (14)

A compressor for compressing and discharging refrigerant;
A condenser for condensing the refrigerant compressed in the compressor;
An expansion device for expanding the refrigerant condensed in the condenser;
An evaporator for evaporating the refrigerant expanded in the expansion device and performing heat exchange with the room air, and discharging the evaporated refrigerant to the compressor;
A bypass unit for bypassing a part of the refrigerant discharged from the condenser to the discharge end of the evaporator;
A heat exchange unit for exchanging heat between a part of the refrigerant discharged from the compressor and the refrigerant before being sucked into the compressor; And
And a control unit for controlling the overall operation of the air conditioner,
Wherein the control unit controls the bypass unit to bypass the refrigerant discharged from the condenser to the discharge end of the evaporator during an oil recovery operation. The method according to claim 1,
The bypass unit includes:
A bypass pipe connecting a condenser and the expansion device, a liquid pipe connecting the condenser and the expansion device, and a gas pipe connecting the evaporator and the compressor,
And an intermittent valve disposed in the bypass pipe for regulating the flow of the refrigerant. 3. The method of claim 2,
Wherein the intermittent valve includes an electronic expansion valve. 3. The method of claim 2,
Wherein the bypass pipe is connected to the gas pipe at a position relatively close to the evaporator among the compressor and the evaporator. 3. The method of claim 2,
And the bypass pipe is connected to the gas pipe at a position adjacent to the evaporator. The method according to claim 1,
Wherein the control unit controls the heat exchanging unit to heat-exchange the refrigerant discharged from the compressor and the refrigerant before being sucked into the compressor during an oil recovery operation. The method according to claim 6,
Further comprising an accumulator disposed in a gas pipe connecting the evaporator and the compressor to restrict the flow of the liquid refrigerant in the refrigerant flowing into the compressor,
The heat exchange unit includes:
A heat exchanger for exchanging heat between a part of the refrigerant discharged from the compressor and the refrigerant stored in the accumulator,
And an adjusting valve for adjusting the flow of the refrigerant supplied to the heat exchanging unit. 8. The method of claim 7,
The bypass unit includes:
A liquid pipe connecting the condenser and the expansion device, a bypass pipe connecting the gas pipe,
And an intermittent valve disposed in the bypass pipe for regulating the flow of the refrigerant. 9. The method of claim 8,
And an oil level sensor for sensing the degree of oil in the compressor. 10. The method of claim 9,
Wherein the control unit comprises:
Wherein the oil recovery operation is performed when the oil level input from the oil level sensor is lower than a reference oil level. 11. The method of claim 10,
Wherein the control unit opens the intermittent valve and the control valve during an oil recovery operation. 9. The method of claim 8,
And a discharge temperature sensor for measuring the temperature of the refrigerant discharged from the evaporator. 13. The method of claim 12,
Wherein the control unit comprises:
And an oil recovery operation is performed when the discharge temperature value input from the discharge temperature sensor is lower than a reference discharge temperature value. 14. The method of claim 13,
Wherein the control unit opens the intermittent valve and the control valve during an oil recovery operation.

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