SCROLL COMPRESSOR AND AIR CONDITIONER INCLUDING THE SAME

Abstract

Provided is a scroll compressor, which includes a stationary scroll including a first wrap, an orbiting scroll including a second wrap, wherein the orbiting scroll and the stationary scroll are disposed to have a phase difference therebetween, and a compression room is formed between the first and second wraps, an inflow part for introducing refrigerant into the compression room, a first introduction part disposed on a side portion of the stationary scroll to inject refrigerant into the compression room, and a second introduction part disposed on another side portion of the stationary scroll to inject refrigerant into the compression room. Pressure of the refrigerant injected by the second introduction part is different from that of refrigerant introduced into the first introduction part. The second wrap moves while the orbiting scroll orbits, and opens the first introduction part before the introduction of the refrigerant through the inflow part is completed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 119 and 35 U.S.C. 365 to Korean Patent Application No. 10-2011-0100555 (filed on Oct. 4, 2011), which is hereby incorporated by reference in its entirety.

BACKGROUND

The present disclosure relates to a scroll compressor and an air conditioner including the scroll compressor.

Air conditioners maintain indoor air in an optimized condition according to its purpose. For example, indoor air may be cooled in summer, and be heated in winter, and indoor humidity may be controlled to adjust the indoor air to a comfortable state. In detail, such an air conditioner performs a cooling cycle for compressing, condensing, expanding, and evaporating refrigerant, to thereby cool or heat an indoor space.

Air conditioners may be classified into separate-type air conditioners in which an indoor device is separated from an outdoor device, and integrated air conditioners in which an indoor device and an outdoor device are integrated. An outdoor device includes an outdoor heat exchanger exchanging heat with external air, and an indoor device includes an indoor heat exchanger exchanging heat with indoor air. Air conditioners may be switched between a cooling mode and a heating mode.

When an air conditioner is operated in a cooling mode, an outdoor heat exchanger may function as a condenser, and an indoor heat exchanger may function as an evaporator. On the contrary, when an air conditioner is operated in a heating mode, an outdoor heat exchanger may function as an evaporator, and an indoor heat exchanger may function as a condenser.

FIG. 6 is a pressure-enthalpy (P-H) diagram illustrating a refrigerant cycle in the related art. Referring to FIG. 6, refrigerant in a state “a” is introduced into a compressor and is compressed to a state “b” therein. After that, the refrigerant is discharged from the compressor and is introduced into a condenser. The refrigerant in the state “b” may be a liquid.

The refrigerant is condensed to a state “c” in the condenser and is discharged. Then, the refrigerant undergoes a throttle process to a state “d”, that is, a two phase state in an expansion device. Then, the refrigerant is introduced into an evaporator and undergoes heat exchange to the state “a”. The refrigerant in the state “a” is a gas that is introduced into the compressor. This refrigerant cycle is repeated.

In this case, a cooling or heating performance may be limited.

In particular, when an outer air condition is bad, that is, when the outer temperature of an area where an air conditioner is installed is excessively high or low, a sufficient amount of refrigerant should be circulated to obtain a desired cooling/heating performance. To this end, a high capacity compressor having an excellent performance is needed, which may increase manufacturing or installation costs of the air conditioner.

In general, when a supercooling degree of refrigerant is ensured, and refrigerant discharged from a condenser is in a supercooled state, an evaporation performance of an evaporator, that is, an area under a line d-a is increased, thereby improving a system performance. However, a system as illustrated in FIG. 6 cannot ensure a supercooling degree of refrigerant, and thus, it is difficult to improve a system performance.

SUMMARY

Embodiments provide a scroll compressor adapted for increasing the amount of refrigerant injected into a compressor, and an air conditioner including the scroll compressor.

In one embodiment, a scroll compressor including: a stationary scroll including a first wrap; an orbiting scroll including a second wrap, wherein the orbiting scroll and the stationary scroll are disposed to have a phase difference therebetween, and a compression room is formed between the first and second wraps; an inflow part for introducing refrigerant into the compression room; a first introduction part disposed on a side portion of the stationary scroll to inject refrigerant into the compression room; and a second introduction part disposed on another side portion of the stationary scroll to inject refrigerant into the compression room, wherein pressure of the refrigerant injected by the second introduction part is different from that of refrigerant introduced into the first introduction part, wherein the second wrap moves while the orbiting scroll orbits, and opens the first introduction part before the introduction of the refrigerant through the inflow part is completed.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a configuration of an air conditioner according to an embodiment.

FIG. 2 is a pressure-enthalpy (P-H) diagram illustrating a refrigerant system according to operations of an air conditioner according to an embodiment.

FIG. 3 is a cross-sectional view illustrating a scroll compressor according to an embodiment.

FIG. 4 is a partial cut-away perspective view illustrating a portion of a scroll compressor according to an embodiment.

FIG. 5 is a cross-sectional view illustrating relative positions of scroll wraps and injection introduction parts in a scroll compressor according to an embodiment.

FIG. 6 is a pressure-enthalpy (P-H) diagram illustrating a refrigerant system according to operations of an air conditioner in the related art.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. The disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, that alternate embodiments falling within the spirit and scope of the present disclosure will fully convey the concept of the disclosure to those skilled in the art.

FIG. 1 is a schematic view illustrating a configuration of an air conditioner according to an embodiment. FIG. 2 is a pressure-enthalpy (P-H) diagram illustrating a refrigerant system according to operations of the air conditioner of FIG. 1.

Referring to FIGS. 1 and 2, an air conditioner 1 according to the current embodiment drives a cooling cycle through which refrigerant circulates. The air conditioner 1 may perform a cooling or heating operation according to a circulation direction of the refrigerant.

When the air conditioner 1 performs a cooling operation, the air conditioner 1 includes: a compressor 10 for compressing refrigerant; a condenser 20 for condensing the refrigerant compressed at the compressor 10; a first expansion device 30 and a second expansion device 60, which selectively expand the refrigerant condensed at the condenser 20; an evaporator 70 for evaporating the refrigerant expanded by the first and second expansion devices 30 and 60; and refrigerant tubes 15 connecting the above components to guide flows of the refrigerant.

The compressor 10 may perform a multi-stage compression operation, and be a scroll compressor that compresses refrigerant by using a relative phase difference between a stationary scroll and an orbiting scroll, which will be described later in more detail.

The air conditioner 1 includes a plurality of supercooling devices 40 and 50 for supercooling the refrigerant discharged from the condenser 20. The supercooling devices 40 and 50 include: a second supercooling device 50 for supercooling the refrigerant discharged from the first expansion device 30; and a first supercooling device 40 for supercooling the refrigerant discharged from the second supercooling device 50. Refrigerant discharged from the condenser 20 may not be expanded through the first expansion device 30.

The air conditioner 1 includes: a second injection passage 90 as a bypass through which at least one of refrigerant discharged from the first expansion device 30 flows; and a second injection expansion part 95 disposed on the second injection passage 90 to adjust a bypass amount of the refrigerant. In this case, the refrigerant may be expanded while passing through the second injection expansion part 95.

A portion of refrigerant discharged from the first expansion device 30 may pass through the second injection passage 90 as a bypass, and is referred to as “first branch refrigerant”. The rest of the refrigerant except for the first branch refrigerant is refereed to as “main refrigerant”. The main refrigerant exchanges heat with the first branch refrigerant in the second supercooling device 50.

While passing through the second injection expansion part 95, the first branch refrigerant is expanded to a low temperature/low pressure state. Thus, while the first branch refrigerant exchanges heat with the main refrigerant, the first branch refrigerant absorbs heat from the main refrigerant, and the main refrigerant emits heat to the first branch refrigerant. Accordingly, the main refrigerant is supercooled. After passing through the second supercooling device 50, the first branch refrigerant is introduced (injected) into the compressor 10 through the second injection passage 90.

The second injection passage 90 includes a second injection introduction part 91 for injecting refrigerant into the compressor 10. The second injection introduction part 91 is connected to a first point of the compressor 10.

The air conditioner 1 includes: a first injection passage 80 as a bypass through which at least one of the main refrigerant discharged from the second supercooling device 50 flows; and a first injection expansion part 85 disposed on the first injection passage 80 to adjust a bypass amount of the main refrigerant. In this case, the main refrigerant may be expanded while passing through the first injection expansion part 85.

Refrigerant, passing through the first injection passage 80 as a bypass, may be referred to as “second branch refrigerant”. The main refrigerant exchanges heat with the second branch refrigerant in the first supercooling device 40.

While passing through the first injection expansion part 85, the second branch refrigerant is expanded to a low temperature/low pressure state. Thus, while the second branch refrigerant exchanges heat with the main refrigerant, the second branch refrigerant absorbs heat from the main refrigerant, and the main refrigerant emits heat to the second branch refrigerant. Accordingly, the main refrigerant is supercooled. After passing through the first supercooling device 40, the second branch refrigerant is introduced (injected) into the compressor 10 through the first injection passage 80.

The first injection passage 80 includes a first injection introduction part 81 for injecting refrigerant into the compressor 10. The first injection introduction part 81 is connected to a second point of the compressor 10. That is, the first injection introduction part 81 and the second injection introduction part 91 are connected to different points on the compressor 10.

The main refrigerant discharged from the first supercooling device 40 is expanded through the second expansion device 60 and is then introduced into the evaporator 70.

A P-H diagram of refrigerant circulating through an air conditioner will now be described with reference to FIG. 2.

Refrigerant (in a state A) introduced into the compressor 10 is compressed in the compressor 10 and is mixed with refrigerant injected into the compressor 10 through the first injection passage 80. The mixed refrigerant is in a state B. A process of compressing refrigerant from the state A to the state B is referred to as “first stage compression”.

The refrigerant (in the state B) is further compressed and is then mixed with refrigerant injected into the compressor through the second injection passage 90. The mixed refrigerant is in a state C. A process of compressing refrigerant from the state B to the state C is referred to as “second stage compression”.

The refrigerant (in the state C) is further compressed to a state D and is then introduced into the condenser 20. After that, when being discharged from the condenser 20, the refrigerant is in a state E.

A portion (the first branch refrigerant) of the refrigerant discharged from the condenser 20 is expanded (to a state K) through the second injection expansion part 95 as a bypass, and exchanges heat with the main refrigerant in the state E. At this point, the main refrigerant in the state E is supercooled to a state G. Meanwhile, the first branch refrigerant in the state K is injected into the compressor 10 and is then mixed with refrigerant staying within the compressor 10, so as to be in the state C.

A portion (the second branch refrigerant) of the main refrigerant (in the state G) discharged from the second supercooling device 50 is expanded (to a state M) through the first injection expansion part 85 as a bypass, and exchanges heat with the main refrigerant. At this point, the main refrigerant in the state G is supercooled to a state H. Meanwhile, the second branch refrigerant in the state M is injected into the compressor 10 and is then mixed with refrigerant staying within the compressor 10, so as to be in the state B.

The main refrigerant, supercooled to the state H, is expanded in the second expansion device 60 and is then introduced into the evaporator 70 to undergo heat exchange. After that, the main refrigerant is introduced into the compressor 10.

Pressure corresponding to a line D-H may be referred to as “high pressure”. Pressure corresponding to a line C-K, that is, pressure in the second injection passage 90 may be referred to as “second middle pressure”. Pressure corresponding to a line B-M, that is, pressure in the first injection passage may be referred to as “first middle pressure”. Pressure corresponding to a line A-I may be referred to as “low pressure”.

A flow rate Q1 of the refrigerant injected into the compressor 10 through the first injection passage 80 may be proportional to a difference between the high pressure and the first middle pressure. A flow rate Q2 of the refrigerant injected into the compressor 10 through the second injection passage 90 may be proportional to a difference between the high pressure and the second middle pressure. Thus, as the first middle pressure and the second middle pressure are shifted to the low pressure, a flow rate of refrigerant injected into the compressor 10 may be increased.

FIG. 3 is a cross-sectional view illustrating a scroll compressor according to the current embodiment. FIG. 4 is a partial cut-away perspective view illustrating a portion of the scroll compressor of FIG. 3.

Referring to FIGS. 3 and 4, the compressor 10 (also referred to as a scroll compressor) includes: a housing 110 forming an appearance; a discharge cover 112 closing the upper part of the housing 110; and a base cover 116 disposed on the lower part of the housing 110 to store oil. A refrigerant inflow part 111 is disposed in at least one portion of the discharge cover 112 to introduce refrigerant into the compressor 10.

The scroll compressor 10 includes: a motor 160 accommodated in the housing 110 to generate torque; a driving shaft 150 rotatably passing through the center of the motor 160; a main frame 140 supporting the upper part of the driving shaft 150; and a compressing part disposed above the main frame 140 to compress refrigerant.

The motor 160 includes: a stator 161 coupled to an inner circumferential surface of the housing 110; and a rotator 162 rotating within the stator 161. The driving shaft 150 passes through the central part of the rotator 162.

An oil supply passage 157 is eccentrically disposed in the central part of the driving shaft 150, so that oil introduced into the oil supply passage 157 can be moved upward by centrifugal force generated according to rotation of the driving shaft 150. An oil supply part 155 is coupled to the lower part of the driving shaft 150, and is rotated integrally with the driving shaft 150 to move oil stored in the base cover 116, to the oil supply passage 157.

The compression part includes: a stationary scroll 120 fixed to the top of the main frame 140 and communicating with the refrigerant inflow part 111; an orbiting scroll 130 engaging with the stationary scroll 120 to form a compression room, and supported by the top of the main frame 140; and an Oldham's ring 131 disposed between the orbiting scroll 130 and the main frame 140 to prevent rotation of the orbiting scroll 130 while the orbiting scroll 130 orbits. The orbiting scroll 130 is coupled to the driving shaft 150 to receive torque from the driving shaft 150.

The stationary scroll 120 and the orbiting scroll 130 are disposed to have a phase difference of about 180 degrees therebetween. The stationary scroll 120 includes a stationary scroll wrap 123 having a spiral shape. The orbiting scroll 130 includes an orbiting scroll wrap 132 having a spiral shape. For convenience, the stationary scroll wrap 123 is referred to as “a first wrap”, and the orbiting scroll wrap 132 is referred to as “a second wrap”.

A plurality of compression rooms may be formed by engagement of the stationary scroll wrap 123 and the orbiting scroll wrap 132. Refrigerant introduced into the compression rooms can be compressed to high temperature by an orbit motion of the orbiting scroll 130. A discharge hole 121, through which highly compressed refrigerant and an oil fluid are discharged, is disposed in approximately the upper central part of the stationary scroll 120.

In particular, the compression rooms are moved toward the center of the discharge hole 121 by an orbit motion of the orbiting scroll 130. Accordingly, the volume of the compression rooms is decreased, and refrigerant compressed in the compression rooms is discharged out of the stationary scroll 120 through the discharge hole 121.

An outlet hole 122 is disposed in a side portion of the stationary scroll 120 to downwardly move a high pressure fluid discharged through the discharge hole 121. The high pressure fluid discharged through the outlet hole 122 is introduced into the housing 110 and is then discharged through a discharge tube 114.

The first injection introduction part 81 and the second injection introduction part 91 are coupled to the stationary scroll 120 through the discharge cover 112. The stationary scroll 120 includes: a first injection hole 124 to which the first injection introduction part 81 is coupled; and a second injection hole 125 to which the second injection introduction part 91 is coupled. The first injection introduction part 81 and the second injection introduction part 91 may be inserted in the first injection hole 124 and the second injection hole 125, respectively.

The first injection hole 124 and the second injection hole 125 are provided with sealing parts 127 for preventing leakage of injected refrigerant out of the stationary scroll 120. The sealing parts 127 may surround outer circumferential surfaces of the first and second injection introduction parts 81 and 91, respectively.

While the orbiting scroll 130 orbits, the orbiting scroll wrap 132 selectively opens and closes the refrigerant inflow part 111, the first injection hole 124, and the second injection hole 125. For example, an outer circumferential surface of the orbiting scroll wrap 132 may selectively close the refrigerant inflow part 111, and a top surface thereof may selectively close the first and second injection holes 124 and 125.

In particular, when the orbiting scroll wrap 132 is located in a first position, or the driving shaft 150 is located at a first angle, the refrigerant inflow part 111 is opened to introduce refrigerant into the compressor 10. While the orbiting scroll 130 further orbits, the orbiting scroll wrap 132 closes the refrigerant inflow part 111, and the refrigerant accommodated in the compression rooms is compressed and is then discharged through the discharge hole 121. As such, a process of opening and closing the refrigerant inflow part 111, and a process of compressing refrigerant are repeated by an orbit motion of the orbiting scroll 130.

In the process of compressing refrigerant, refrigerant located in the first or second injection passage 80 or 90 is selectively injected into the compression rooms through the first or second injection introduction part 81 or 91.

A refrigerant cycle may be varied, depending on positions of the first and second injection introduction parts 81 and 91. The positions of the first and second injection introduction parts 81 and 91 are used to determine whether the first and second injection introduction parts 81 and 91 are opened when the orbiting scroll 130 orbits for predetermined time from a point of time when introduction of refrigerant through the refrigerant inflow part 111 is completed. An orbit amount of the orbiting scroll 130 may correspond to a rotation amount of the driving shaft 150.

In other words, it is determined whether refrigerant is injected through the first or second injection introduction part 81 or 91 when refrigerant is compressed for predetermined time from a point of time when the refrigerant is introduced through the refrigerant inflow part 111. This will now be described in detail with reference to the accompanying drawings.

FIG. 5 is a cross-sectional view illustrating relative positions of scroll wraps and injection introduction parts in a scroll compressor according to the current embodiment.

Referring to FIG. 5, the orbiting scroll 130 engages with the stationary scroll 120 to form compression rooms. Then, the orbiting scroll 130 orbits to move the compression rooms toward the center of the stationary scroll 120, whereby the volume of the compression rooms is decreased.

The first injection introduction part 81 and the second injection introduction part 91 may be disposed on different positions, respectively, on the stationary scroll 120. For example, an imaginary line connecting the first injection introduction part 81 and the second injection introduction part 91 may pass through a point corresponding to the central part of the stationary scroll 120, that is, to the discharge hole 121. That is, the first injection introduction part 81 and the second injection introduction part 91 may be disposed to face each other with the discharge hole 121 as the center therebetween.

While the orbiting scroll 130 orbits, the compression rooms may move toward the first or second injection introduction part 81 or 91. When one of the compression rooms is located in a position corresponding to the first injection introduction part 81, refrigerant is introduced into the compression room through the first injection introduction part 81. When one of the compression rooms is located in a position corresponding to the second injection introduction part 91, refrigerant is introduced into the compression room through the second injection introduction part 91. At this point, the compression room into which the refrigerant is introduced through the first injection introduction part 81 is different from the compression room into which the refrigerant is introduced through the second injection introduction part 91.

The first and second injection holes 124 and 125 may selectively opened by the orbiting scroll wrap 132. For example, when the first injection hole 124 is opened, the second injection hole 125 may be closed by the orbiting scroll wrap 132. In addition, when the second injection hole 125 is opened, the first injection hole 124 may be closed by the orbiting scroll wrap 132.

In particular, opening of the first injection hole 124 may be started before introduction of refrigerant through the refrigerant inflow part 111 is completed. While the orbiting scroll wrap 132 orbits, the first injection hole 124 may be gradually opened for predetermined time. That is, the orbiting scroll wrap 132 may be disposed to open the first injection hole 124 before introduction of refrigerant through the refrigerant inflow part 111 is completed.

Thus, even in the case that the first injection hole 124 is opened to start injection of refrigerant before introduction of refrigerant through the refrigerant inflow part 111 is completed, a point of time when the first injection hole 124 is completely opened to increase an injection amount of the refrigerant may be a point of time when the refrigerant inflow part 111 is closed, or a point of time when the refrigerant is compressed after the closing of the refrigerant inflow part 111.

For example, when introduction of refrigerant through the refrigerant inflow part 111 is completed, that is, when the refrigerant inflow part 111 is closed by the orbiting scroll wrap 132, a rotation angle of the driving shaft 150 may be about 0°. In this case, opening of the first injection hole 124 may be started when the rotation angle of the driving shaft 150 ranges from about −10° to about −30°.

The introduction of the refrigerant is completed when the rotation angle of the driving shaft 150 may be about 0°, and the refrigerant is further compressed when the rotation angle of the driving shaft 150 may be increased to about 10° or 20°. Thus, the rotation angle of the driving shaft 150 may be a negative value before the introduction of the refrigerant is completed.

When the refrigerant inflow part 111 is closed by the orbiting scroll wrap 132 by further rotation of the driving shaft 150, that is, when the introduction of the refrigerant is completed, the first injection hole 124 is completely opened, so that a large amount of refrigerant can be injected therethrough. As such, when the introduction of the refrigerant into the compressor 10 is completed, refrigerant may be injected through the first injection hole 124. At this point, the first middle pressure is low in the above P-H diagram, and thus, the injection amount of the refrigerant can be increased.

The refrigerant injected through the first injection hole 124 is mixed with the refrigerant accommodated in the compressor 10, and undergoes the second stage compression.

Opening of the second injection hole 125 may be started when the rotation angle of the driving shaft 150 (or a rotation angle of the orbiting scroll wrap 132) is about 180° from an angle determined when the opening of the first injection hole 124 is started. For example, when the rotation angle of the driving shaft 150 is about −20°, the opening of the first injection hole 124 may be started. In this case, when the rotation angle of the driving shaft 150 is about 160°, the opening of the second injection hole 125 may be started.

When the opening of the second injection hole 125 is started, the first injection hole 124 may be closed by the orbiting scroll wrap 132. While the driving shaft 150 is rotated through about 180° as described above, the second stage compression is carried out in the compressor 10. Before the second stage compression is completed, the opening of the second injection hole 125 may be started.

When the driving shaft 150 is further rotated from when the opening of the second injection hole 125 is started, the second injection hole 125 is completely opened to increase an injection amount of refrigerant. Approximately at this point, the second stage compression may be completed.

The refrigerant injected through the second injection hole 125 is mixed with the refrigerant accommodated in the compressor 10, and undergoes third stage compression. After that, the refrigerant may be discharged out of the stationary scroll 120 through the discharge hole 121.

When the driving shaft 150 is rotated through about 180° from when the opening of the second injection hole 125 is started, the first injection hole 124 may be opened. That is, when the rotation angle of the driving shaft 150 is about 340°, in other words, when the driving shaft 150 is located at an angle of −20° from one revolution corresponding to 360°, the first injection hole 124 may be opened.

As such, when introduction of refrigerant into the compressor 10 is completed, refrigerant may be substantially injected through the first injection passage 80, thereby decreasing the first middle pressure. Accordingly, a large amount of refrigerant can be injected.

Another embodiment is proposed.

Although a plurality of supercooling devices are used to inject refrigerant having middle pressure in FIG. 1, at least one of the supercooling devices may be replaced with a phase separator. The phase separator may separate gaseous refrigerant, as at least one portion of two-phase refrigerant, therefrom to introduce the gaseous refrigerant to a compressor as described above.

According to the embodiments, refrigerant fluids are introduced into different points on a scroll compressor, so as to increase a refrigerant circulation amount of a system, thereby improving a cooling/heating performance.

In addition, since refrigerant having middle pressure can be injected into the compressor, power needed for compressing refrigerant in the compressor can be saved, thereby improving cooling/heating efficiency.

In addition, opening of a first injection introduction part is started before introduction of refrigerant into the compressor through a refrigerant inflow part is completed, and refrigerant can be injected into the compressor when refrigerant undergoes first stage compression in the compressor. Thus, pressure (middle pressure) of the injected refrigerant can be decreased, thereby increasing a flow rate thereof.

In addition, since the first injection introduction part and a second injection introduction part, disposed in the compressor, has a predetermined phase difference therebetween, opening and closing timing of the first and second injection introduction parts can be optimized, thus efficiently injecting and compressing refrigerant.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the preferred embodiments should be considered in descriptive sense only and not for purposes of limitation, and also the technical scope of the invention is not limited to the embodiments. Furthermore, is defined not by the detailed description of the invention but by the appended claims, and all differences within the scope will be construed as being comprised in the present disclosure.

Claims

1. A scroll compressor comprising:

a stationary scroll comprising a first wrap;

an orbiting scroll comprising a second wrap, wherein the orbiting scroll and the stationary scroll are disposed to have a phase difference therebetween, and a compression room is formed between the first and second wraps;

an inflow part for introducing refrigerant into the compression room;

a first introduction part disposed on a side portion of the stationary scroll to inject refrigerant into the compression room; and

a second introduction part disposed on another side portion of the stationary scroll to inject refrigerant into the compression room, wherein pressure of the refrigerant injected by the second introduction part is different from that of refrigerant introduced into the first introduction part,

wherein the second wrap moves while the orbiting scroll orbits, and opens the first introduction part before the introduction of the refrigerant through the inflow part is completed.

2. The scroll compressor according to claim 1, wherein while the orbiting scroll orbits, the second wrap closes at least one of the inflow part, the first introduction part, and the second introduction part.

3. The scroll compressor according to claim 2, further comprising a driving shaft for transmitting torque to the orbiting scroll,

wherein when the introduction of the refrigerant through the inflow part is completed, a rotation angle of the driving shaft is about 0°, and

the opening of the first introduction part is started when the rotation angle of the driving shaft ranges from about −10° to about −30°.

4. The scroll compressor according to claim 3, wherein the second wrap opens one of the first introduction part and the second introduction part, and closes the other one.

5. The scroll compressor according to claim 4, wherein the opening of the second introduction part is started when the rotation angle is increased by about 180° after the opening of the first introduction part is started.

6. The scroll compressor according to claim 1, wherein a discharge hole is disposed in a central part of the stationary scroll to discharge refrigerant compressed in the compression room, and

an imaginary line connecting the first introduction part and the second introduction part passes through the discharge hole.

7. The scroll compressor according to claim 1, further comprising a discharge cover that closes an upper part of the stationary scroll and an upper part of the orbiting scroll,

wherein the first introduction part and the second introduction part pass through the discharge cover, and couple to a top surface of the stationary scroll.

8. The scroll compressor according to claim 1, wherein the stationary scroll comprises:

an injection hole in which the first or second introduction part is inserted; and

a sealing part surrounding an outer circumferential surface of the first or second introduction part.

9. The scroll compressor according to claim 1, wherein the first introduction part is disposed in a position where refrigerant having first middle pressure is injected, and

the second introduction part is disposed in a position where refrigerant having second middle pressure higher than the first middle pressure is injected.

10. The scroll compressor according to claim 9, wherein after refrigerant introduced through the inflow part undergoes first stage compression, the refrigerant is mixed with refrigerant injected through the first introduction part and then undergoes second stage compression, and

after the second stage compression, the refrigerant is mixed with refrigerant injected through the second introduction part and then undergoes third stage compression.

11. An air conditioner comprising:

a compressor for compressing refrigerant;

a condenser for condensing the refrigerant compressed at the compressor;

a second injection passage as a bypass through which at least one portion of the refrigerant discharged from the condenser is injected into the compressor;

a first injection passage through which refrigerant having pressure lower than that of the refrigerant of the second injection passage is injected into the compressor; and

an evaporator in which a portion of the refrigerant discharged from the condenser is evaporated after undergoing a throttle process in an expansion device,

wherein the compressor comprises:

a refrigerant inflow part in which the refrigerant passing through the evaporator is introduced; and

an orbiting scroll wrap that orbits to selectively close at least one of the refrigerant inflow part and the first injection passage and to open the first injection passage before the refrigerant inflow part is closed.

12. The air conditioner according to claim 11, wherein the compressor further comprises a motor for generating torque and a driving shaft rotatably passing through a center of the motor, and

the orbiting scroll wrap is coupled to the driving shaft and is allowed to orbit.

13. The air conditioner according to claim 12, wherein when the refrigerant inflow part is closed by the orbiting scroll wrap, the first injection passage is completely opened.

14. The air conditioner according to claim 12, wherein opening of the second injection passage is started when the orbiting scroll wrap further orbits through about 180° after opening of the first injection passage is started.

15. The air conditioner according to claim 11, further comprising a plurality of supercooling devices for supercooling refrigerant after passing through the condenser,

wherein the supercooling devices comprise:

a first supercooling device in which the refrigerant of the first injection passage undergoes heat exchange; and

a second supercooling device in which the refrigerant of the second injection passage undergoes heat exchange.

16. The air conditioner according to claim 15, wherein the first supercooling device supercools the refrigerant discharged from the second supercooling device.