KR20100062115A - Air conditioner and control method thereof - Google Patents

Abstract

PURPOSE: An air conditioner and a control method are provided to reduce the damage of a check valve and valve noise by modifying the vibration of a check valve. CONSTITUTION: An air conditioner comprises: an outdoor heat exchanger(12); an indoor heat exchanger(21); a receiver(14); a check valve(18) which is installed in a pipe which interlinks the outdoor heat exchanger and the receiver and allows the refrigerant to flow from the outdoor heat exchanger to the receiver; a refrigerant valve which is connected to the check valve in parallel; a controller which reduced the pressure of the receiver by opening the refrigerant valve if the pressure of both ends of the check valve is reversed in the cooling operation; and a compressor(10) which proceeds a loading operation which refrigerant is compressed and an unloading operation which stops the compressing of the refrigerant.

Description

Air conditioner and its control method {AIR CONDITIONER AND CONTROL METHOD THEREOF}

The present invention relates to an air conditioner and a control method thereof, and more particularly, to an air conditioner including a loading operation for compressing a refrigerant and a compressor for performing an unloading operation in which the refrigerant compression is stopped. And a control method thereof.

Air conditioner As an example, the heat pump type air conditioner is a device configured to switch the circulation direction of the refrigerant in the refrigerant cycle to serve not only in summer cooling but also in winter heating.

The heat pump type air conditioner adjusts the four-way valve so that the refrigerant discharged from the compressor is sucked into the outdoor heat exchanger during the cooling operation so that the refrigerant is condensed in the outdoor heat exchanger. The evaporation in the heat exchanger takes the heat from the room air and performs cooling. The refrigerant passing through the indoor heat exchanger is sucked back into the compressor through the four-way valve and compressed.

In addition, by controlling the four-way valve so that the refrigerant discharged from the compressor is sucked into the indoor heat exchanger during the heating operation, the condensation of the refrigerant occurs in the indoor heat exchanger to supply heat to the indoor air to perform the heating operation. The refrigerant passing through the indoor heat exchanger is depressurized by the outdoor expansion valve and then sucked back into the compressor after passing through the outdoor heat exchanger and the four-way valve.

The heat pump type air conditioner includes a receiver in a pipe connecting the outdoor heat exchanger and the indoor heat exchanger. The receiver consists of a pressure vessel for storing a refrigerant, and when the amount of refrigerant in the system is large, it stores the excess refrigerant and serves to separate the gaseous and liquid refrigerant from the stored refrigerant.

In the heat pump type air conditioner having the above-mentioned receiver, an expansion valve and an check valve are installed in parallel between the outdoor heat exchanger and the receiver. When the refrigerant circulates through the expansion valve during the cooling operation, the pressure drop increases. Therefore, the check valve is connected to the expansion valve in parallel so that the refrigerant from the outdoor heat exchanger can flow to the receiver without passing through the expansion valve. For example, during the cooling operation, the expansion valve is closed to allow the refrigerant to flow through only the check valve, and during the heating operation, the refrigerant flows to the opposite side. Therefore, the expansion valve is opened so that the refrigerant does not flow through the check valve and passes only through the expansion valve. Let it flow

Recently, a variable displacement compressor has been used to improve energy efficiency in a heat pump type air conditioner having the above-described configuration. The variable speed compressor is mainly used for variable speed rotation and pulse width modulation (PWM). In the PWM compressor, the capacity of the compressor is changed according to a duty control signal for determining a loading time when the refrigerant is compressed and an unloading time when the refrigerant is stopped.

In the case of the heat pump type air conditioner including the PWM compressor, the receiver, the expansion valve, and the check valve, when the compressor is loaded during the cooling operation and the refrigerant is compressed, the high temperature and high pressure refrigerant discharged from the compressor Blur in order of outdoor heat exchanger, check valve and receiver. While the refrigerant is being compressed, pressure is applied to the pressure vessel called the receiver, so the pressure on the outdoor heat exchanger side is high and the pressure on the receiver side is relatively low relative to the check valve.

On the other hand, when the compressor is changed from the loading operation to the unloading operation and the refrigerant compression is stopped, the pressure applied to the receiver remains while the refrigerant compression is stopped, so that the pressure at the receiver is high and the pressure at the outdoor heat exchanger is relatively low. . Therefore, the pressure at the receiver side becomes higher than the pressure at the outdoor heat exchanger side based on the check valve. That is, the pressure of both ends of the check valve is reversed based on the check valve at the moment the compressor stops compressing the refrigerant while compressing the refrigerant. As a result, a moving object such as a slide in the check valve is shaken (Chattering), the shock is applied to the check valve, and noise is generated.

One side of the present invention is that if the pressure at both ends of the check valve provided in the pipe connecting the outdoor heat exchanger and the receiver during the cooling operation is reversed, the refrigerant bypasses the check valve in the receiver to flow to the outdoor heat exchanger to lower the pressure on the receiver side It is to provide an air conditioner and a control method thereof.

To this end, an air conditioner according to an embodiment of the present invention is an air conditioner having a receiver in which a part of a refrigerant circulating an outdoor heat exchanger and an indoor heat exchanger is stored, the refrigerant being installed in a pipe connecting the outdoor heat exchanger and the receiver. A check valve which flows in the direction from the outdoor heat exchanger to the receiver, a refrigerant valve connected in parallel with the check valve, and when the pressures at both ends of the check valve are reversed during cooling operation, the refrigerant valve is opened to open the receiver side. It includes a control unit to lower the pressure of.

In addition, the control method of the air conditioner according to another embodiment of the present invention includes a compressor for performing a loading operation in which the refrigerant is compressed and an unloading operation in which the refrigerant compression is stopped, and a portion of the refrigerant circulating the outdoor heat exchanger and the indoor heat exchanger are stored. And a check valve installed in a pipe connecting the outdoor heat exchanger and the receiver, the refrigerant flowing in the direction from the outdoor heat exchanger to the receiver, and a refrigerant valve connected in parallel with the check valve. In the control method, during the cooling operation, it is determined whether the compressor is changed from the loading operation to the unloading operation, and when the compressor is changed from the loading operation to the unloading operation, the refrigerant valve is opened to open the receiver side. It is to lower the pressure of.

In addition, the control method of the air conditioner according to another embodiment of the present invention includes a compressor for performing a loading operation in which the refrigerant is compressed and an unloading operation in which the refrigerant compression is stopped, a part of the refrigerant circulating the outdoor heat exchanger and the indoor heat exchanger An air conditioner having a stored receiver, a check valve installed in a pipe connecting the outdoor heat exchanger and the receiver to allow a refrigerant to flow in the direction from the outdoor heat exchanger to the receiver, and a refrigerant valve connected in parallel with the check valve In the control method of the present invention, during the cooling operation, it is determined whether the compressor is changed from a full load operation in which only the loading operation is performed to a partial load operation in which the loading operation and the unloading operation are repeated, and the compressor is at the full load. When changing from the operation to the partial load operation, opening the refrigerant valve It involves the lowered pressure of the side.

According to an embodiment of the present invention described above, when the pressure in both ends of the check valve provided in the pipe connecting the outdoor heat exchanger and the receiver during the cooling operation is reversed due to the compressor is changed from the loading operation to the unloading operation during the cooling operation. In addition, the refrigerant bypasses the check valve in the receiver and flows to the outdoor heat exchanger, thereby lowering the pressure on the receiver side, thereby improving vibration of the check valve and reducing damage to the check valve and valve noise.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention.

1 shows a refrigerant cycle of an air conditioner according to an embodiment of the present invention. As shown in Figure 1, the air conditioner according to an embodiment of the present invention includes an outdoor unit (A) and the indoor unit (B).

The outdoor unit A includes a compressor 10, a four-way valve 11, an outdoor heat exchanger 12, an outdoor fan 13, an outdoor expansion valve 16, a check valve 18, a receiver 14 and an accumulator ( 19).

The four-way valve 11 switches the flow of the refrigerant discharged from the compressor 10 to the cooling mode or the heating mode.

The outdoor heat exchanger 12 exchanges heat with outdoor air while the refrigerant passes therethrough. The outdoor heat exchanger 12 functions as a condenser during the cooling operation to allow the refrigerant to condense through heat dissipation, and functions as an evaporator during the heating operation to allow the refrigerant to evaporate through the endotherm.

The outdoor fan 13 blows the outdoor air to the outdoor heat exchanger 12 for heat exchange between the outdoor air and the refrigerant.

The check valve 18 is installed in the refrigerant pipe 17 connecting the outdoor heat exchanger 12 and the receiver 14. The check valve 18 is a valve for allowing the refrigerant to flow in only one direction. That is, the check valve 18 passes the refrigerant flow from the outdoor heat exchanger 12 to the receiver 14 and does not allow the refrigerant flow from the receiver 14 to the outdoor heat exchanger 12.

The outdoor side expansion valve 16 is installed in the bypass pipe 15 for bypassing the refrigerant pipe 17 connecting the outdoor heat exchanger 12 and the receiver 14. The outdoor expansion valve 16 is normally closed during the cooling operation and opened during the heating operation. The outdoor expansion valve 16 is an electronic expansion valve in which the opening amount is controlled by an external signal.

Therefore, the refrigerant passing through the outdoor heat exchanger 12 passes through the check valve 18 to the receiver 14 during the cooling operation, and the refrigerant passing through the receiver 14 passes through the outdoor expansion valve 16 during the heating operation. And flows to the outdoor heat exchanger (16).

The receiver 14 stores some of the refrigerant circulating in the outdoor heat exchanger 12 and the indoor heat exchanger 21. In the receiver 14, the refrigerant is separated into a gas phase refrigerant and a liquid refrigerant.

The accumulator 19 separates the gas phase refrigerant and the liquid refrigerant from the refrigerant flowing into the suction side of the compressor 10.

In addition, the indoor unit B includes an indoor expansion valve 20, an indoor heat exchanger 21, and an indoor fan 22.

The indoor heat exchanger 21 exchanges heat with indoor air while the refrigerant passes. The indoor heat exchanger 21 functions as an evaporator during the cooling operation so that the refrigerant evaporates through endothermic, and functions as a condenser during the heating operation so that the refrigerant condenses through heat dissipation.

The indoor fan 22 blows the indoor air to the indoor heat exchanger 21 for heat exchange between the indoor air and the refrigerant.

The indoor expansion valve 20 decompresses the refrigerant flowing into the indoor heat exchanger 21.

An air conditioner according to an embodiment of the present invention controls the four-way valve 11 installed in the outdoor unit A to change the refrigerant flow to perform a heating operation or an cooling operation.

In the cooling operation, the coolant flows in the direction of the solid arrow. That is, the high temperature and high pressure refrigerant discharged from the compressor 10 is condensed while passing through the outdoor heat exchanger 12. The refrigerant passing through the outdoor heat exchanger 12 passes through the check valve 18 and then passes through the receiver 14 while the excess refrigerant is stored in the receiver 14. The refrigerant passing through the receiver 14 is depressurized by the indoor expansion valve 20 and then evaporated in the indoor heat exchanger 21 to extract heat from the indoor air to perform cooling. The refrigerant passing through the indoor heat exchanger 21 is sucked into the compressor 10 through the four-way valve 11 and the accumulator 19 and compressed.

Meanwhile, during the heating operation, the refrigerant flows in the direction of the dotted arrow. That is, the high temperature and high pressure refrigerant discharged from the compressor 10 is condensed in the indoor heat exchanger 21 to discharge heat to the indoor air to perform heating. The refrigerant passing through the indoor heat exchanger 21 is depressurized by the outdoor expansion valve 16 through the receiver 14 and then passes through the outdoor heat exchanger 12 to take heat from the outdoor air and evaporate. The refrigerant passing through the outdoor heat exchanger 12 is sucked into the compressor 10 through the four-way valve 11 and the accumulator 19 and compressed.

2 and 3 show the loading and unloading state of the compressor applied to the air conditioner according to an embodiment of the present invention.

2 and 3, the compressor applied to the air conditioner according to an embodiment of the present invention is a variable displacement compressor (10) controlled by a pulse width modulation (PWM) method.

The compressor 10 includes a casing 30 having a suction port 31 and a discharge port 32, a motor 33 installed inside the casing 30, and a rotating scroll rotating under the rotational force of the motor 33. 34 and a fixed scroll 36 which forms a compression chamber 35 between the swing scroll 34.

The casing 30 is provided with a bypass tube 37 connecting the upper side of the fixed scroll 36 and the inlet 31, and the bypass tube 37 has a PWM (Pulse Width Modulated) valve in the form of a solenoid valve ( 10a) is installed.

2 shows a state where the PWM valve 10a is turned off to block the bypass pipe 37. In this state, the compressor 10 discharges the compressed refrigerant. This state is called loading and the compressor 10 operates at a capacity of 100%. When the PWM valve 10a is turned off and the compressor 10 compresses the refrigerant, it is called loading operation of the compressor 10.

FIG. 3 illustrates a state in which the PWM valve 10a is turned on to open the bypass pipe 37, and the refrigerant is not discharged from the compressor 10. This state is called unloading and the compressor 10 is operated at a capacity of 0%. When the PWM valve 10a is turned on and the compressor 10 stops compressing the refrigerant, it is referred to as unloading operation of the compressor.

Whether the compressor 10 is loaded or unloaded, power is supplied to the compressor 10 and the motor 33 rotates at a constant speed. When the power supply to the compressor 10 is cut off, the motor 33 does not rotate and the operation of the compressor 10 is stopped.

Therefore, the compressor 10 has a variable capacity by the PWM valve 10a controlled according to the duty control signal for determining the loading time for discharging the refrigerant and the unloading time for discharging the refrigerant. At this time, the compressor 10, for example, when one cycle is 20 seconds, a compression work for compressing the refrigerant for a predetermined time (for example, 13 seconds) and does not work for the rest of the time. The power consumption is consumed during the compression work and the refrigerant is compressed, but the power consumption is greatly reduced and the refrigerant is not compressed while the compression work is not performed. In this way, the compressor 10 operates by varying the capacity of the system by adjusting the loading time for the compression work and the unloading time for the non-compression work.

As described above, the compressor 10 is loaded while the high temperature and high pressure refrigerant discharged from the compressor 10 during the cooling operation is blurred in the order of the outdoor heat exchanger 12, the check valve 18, and the receiver 14. When the operation is changed from the unloading operation, the pressure of the both ends of the check valve 18 is reversed based on the check valve 18 at the moment when the compressor compresses the refrigerant and stops the refrigerant compression. For this reason, moving objects, such as a slide in the check valve 18, tremble, an impact is applied to the check valve 18, and a noise is also generated.

Therefore, in one embodiment of the present invention, when the pressure at both ends of the check valve 18 is reversed during the cooling operation, the refrigerant is controlled at the receiver 14 by adjusting the opening amount of the outdoor expansion valve 16. By bypassing 18) and flowing to the outdoor heat exchanger 12 side, the pressure on the receiver 14 side is lowered.

Figure 4 shows a schematic control block diagram of an air conditioner according to an embodiment of the present invention. As shown in Figure 4, the air conditioner according to an embodiment of the present invention includes a control unit 60 for performing the overall control.

An input unit 40 for receiving a command from a user and a sensor unit 50 including various sensors of an air conditioner are electrically connected to an input side of the controller 60.

The four-way valve 11, the compressor 10, the PWM valve 10a, the outdoor expansion valve 16 and the like are electrically connected to the output side of the control unit 60.

When the pressure at both ends of the check valve 18 is reversed during the cooling operation, the controller 60 adjusts the opening amount of the outdoor expansion valve 16 to lower the pressure at the receiver 14. In particular, when the compressor 10 is changed from the loading operation to the unloading operation during the cooling operation, the controller 60 opens the outdoor expansion valve 16 so that the refrigerant bypasses the check valve 18 in the receiver 14. By flowing to the outdoor heat exchanger 12 side, the pressure on the receiver 14 side is lowered, thereby improving damage and valve noise due to the shaking of the check valve 18. At this time, the control unit opens to 50% or less when opening the outdoor expansion valve (16). When the outdoor expansion valve 16 is opened in an amount exceeding 50% of the opening amount, a relatively large amount of refrigerant flows back from the receiver 14 side to the outdoor heat exchanger 12 side than when the opening degree is greater than 50%. Temperature of the discharge side decreases and coolant circulation amount decreases, resulting in a relatively low cooling capacity. Therefore, the opening amount of the outdoor-side electric expansion valve 16 is opened to 50% or less.

Figure 5 shows a control flow chart for the control method of the air conditioner according to an embodiment of the present invention. Referring to FIG. 5, first, the controller 60 receives a cooling request capability from the indoor unit B (S100).

Then, the control unit 60 supplies power to the compressor 10 to turn on the compressor 10 to perform a cooling operation (S110). At this time, the controller 60 closes the outdoor expansion valve 16.

In addition to performing the cooling operation, the controller 60 determines the loading time and the unloading time of the compressor 10 according to the cooling demand capability received from the indoor unit B (S120).

After determining the loading time and the unloading time of the compressor 10, the controller 60 load-operates the compressor 10 according to the determined loading time of the compressor 10 (S130). At this time, the controller 60 turns off the PWM valve 10a so that the refrigerant is compressed in the compressor. As shown in FIG. 6, during the cooling operation, the refrigerant flows in the solid arrow direction. The high temperature and high pressure refrigerant discharged from the compressor 10 is condensed while passing through the outdoor heat exchanger 12. The refrigerant passing through the outdoor heat exchanger 12 passes through the check valve 18 and then passes through the receiver 14, where a portion of the refrigerant is stored in the receiver 14. The refrigerant passing through the receiver 14 is depressurized by the indoor expansion valve 20 and is then evaporated in the indoor heat exchanger 21 to extract heat from the indoor air to perform cooling. The refrigerant passing through the indoor heat exchanger 21 is sucked into the compressor 10 through the four-way valve 11 and the accumulator 19 and compressed. Since the refrigerant pressure is applied to the receiver 14 while the refrigerant is being compressed, the pressure at the outdoor heat exchanger 12 side relative to the check valve 18 is relatively higher than the pressure at the receiver 14 side.

After the loading operation of the compressor 10, it is determined whether the loading time of the compressor 10 has elapsed (S140). If the loading time of the compressor 10 has not passed, the operation mode S130 is performed to perform the following steps.

On the other hand, if the loading time of the compressor 10 has elapsed, the controller 60 changes the compressor 10 from the loading operation to the unloading operation and operates it (S150). At this time, the controller 60 turns on the PWM valve 10a to stop the refrigerant compression in the compressor 10. When the compressor is changed from the loading operation to the unloading operation and the refrigerant compression is stopped, the refrigerant pressure applied to the receiver 14 remains while the refrigerant compression is stopped, so that the pressure on the receiver 14 side based on the check valve 14 is maintained. This pressure is relatively higher than the pressure at the outdoor heat exchanger 12 side. Therefore, when the compressor 10 compresses the refrigerant and stops compressing the refrigerant, the pressures at both ends of the check valve 18 are gradually reversed based on the check valve 18.

In addition to unloading the compressor 10, the controller 60 opens the outdoor expansion valve 16 (S160). As shown in FIG. 7, when the outdoor expansion valve 16 is opened, the refrigerant is checked on the receiver 14 even if the pressure on the receiver 14 side is relatively higher than the pressure on the outdoor heat exchanger 12 side. Since the bypass of the valve 18 flows to the outdoor heat exchanger 12 side, the pressure on the receiver 14 is lowered, so that damage to the check valve 18 and valve noise can be improved. At this time, the controller 60 controls the opening amount of the outdoor expansion valve 16 to open the opening amount to 50% or less. When the outdoor expansion valve 16 is opened more than 50% of the opening amount, a relatively large amount of refrigerant flows back from the receiver 14 side to the outdoor heat exchanger 12 side than when the outdoor expansion valve 16 is opened below 50%. The temperature at the discharge side of 10) is lowered and the amount of refrigerant circulating is decreased, thereby lowering the cooling capacity. Therefore, the opening amount of the outdoor-side electric expansion valve 16 is opened to 50% or less.

FIG. 8 illustrates pressure changes at both ends of the valve control and the check valve of the expansion valve during the loading operation and the unloading operation of the compressor in the air conditioner according to the exemplary embodiment of the present invention. As shown in FIG. 8, when the compressor 10 is changed from the loading operation to the unloading operation, the outdoor expansion valve 16 is opened at the time when the compressor 10 is changed from the loading operation to the unloading operation. . For example, the outdoor expansion valve 16 is opened at an opening amount of 50%. At this time, if the outdoor expansion valve 16 is closed, the first pressure P1 of the outdoor heat exchanger 12 side is the second pressure P2 of the receiver 14 during the loading operation section of the compressor 10. Maintain a higher pressure and during the unloading operation section of the compressor 10, the second pressure P2 on the receiver 14 side is higher than the first pressure P1 on the outdoor heat exchanger 12 side. Keep it. If the expansion valve 16 is opened when the compressor 10 changes to an unloading operation during the loading operation, the second pressure P2 on the receiver 14 side is initially applied to the outdoor heat exchanger 12 at the beginning of the unloading operation. The pressure is higher than the first pressure P1 on the side, and gradually decreases as time passes, and becomes lower than or equal to the first pressure P1 on the outdoor heat exchanger 12 side. At this time, the second pressure P2 on the receiver 14 side may be slightly higher than the first pressure P1 on the outdoor heat exchanger 12 side in a range that does not cause damage to the check valve 18 and valve noise. . In the initial stage when the outdoor expansion valve 16 is opened, since the second pressure P2 at the receiver 14 side is higher than the first pressure P1 at the outdoor heat exchanger 12 side, the refrigerant is at the receiver 14 side. Bypassing the check valve 18 flows to the outdoor heat exchanger 12 side, the pressure on the receiver 14 side is gradually lowered.

As shown in Figs. 8 and 9, the outdoor expansion valve 16 is opened at the time when the compressor 10 is changed from the loading operation to the unloading operation. In addition, the outdoor expansion valve 16 may be closed at a time when the compressor 10 is changed from an unloading operation to a loading operation. However, in this case, the outdoor expansion valve 16 is continuously opened and closed during the part operation (part load operation) section in which the compressor 10 repeats the loading operation and the unloading operation at a constant cycle. The outdoor expansion valve 16 is a valve in which the opening amount is controlled, which takes more time to open and close the valve than a simple on / off valve. Therefore, even if the compressor 10 is changed from the unloading operation to the loading operation, the part of the compressor 10 in which the compressor 10 repeats the loading operation and the unloading operation without immediately closing the outdoor expansion valve 16 immediately. Close after the operation (partial load operation) section is finished.

As shown in FIG. 9, the compressor 10 repeats the loading operation and the unloading operation in the full operation (full load operation) section of the compressor 10 in which the compressor 10 operates only in the loading operation. The outdoor side expansion valve 16 is opened in the case of switching to the part operation (part load operation) section of the compressor, and the outdoor side expansion valve 16 is opened when the part operation (part load operation) section of the compressor 10 is finished. Close it.

10 shows a refrigerant cycle of the air conditioner according to another embodiment of the present invention. As shown in FIG. 10, the air conditioner according to another embodiment of the present invention includes an outdoor unit A and an indoor unit B. FIG.

The outdoor unit A includes a compressor 10, an outdoor heat exchanger 12, an outdoor fan 13, a refrigerant valve 16 ', a check valve, a check valve 18, a receiver 14, and an accumulator 19. do.

The compressor 10 compresses the refrigerant when the PWM valve 10a is turned off and stops the refrigerant compression when the PWM valve 10a is turned on.

The check valve 18 is installed in the refrigerant pipe 17 connecting the outdoor heat exchanger 12 and the receiver 14. The check valve 18 is a valve for allowing the refrigerant to flow in only one direction. That is, the check valve 18 passes the refrigerant flow from the outdoor heat exchanger 12 to the receiver 14 and does not allow the refrigerant flow from the receiver 14 to the outdoor heat exchanger 12.

The refrigerant valve 16 ′ is installed in the bypass pipe 15 for bypassing the refrigerant pipe 17 connecting the outdoor heat exchanger 12 and the receiver 14. The refrigerant valve 16 is an on or off valve that is completely closed or completely open.

During the loading operation of the compressor in which the refrigerant is compressed during the cooling operation, the refrigerant flows in the solid arrow direction. That is, the high temperature and high pressure refrigerant discharged from the compressor 10 is condensed while passing through the outdoor heat exchanger 12. The refrigerant passing through the outdoor heat exchanger 12 passes through the check valve 18 and then passes through the receiver 14 while some refrigerant is stored in the receiver 14. The refrigerant passing through the receiver 14 is depressurized by the indoor expansion valve 20 and is then evaporated in the indoor heat exchanger 21 to extract heat from the indoor air to perform cooling. The refrigerant passing through the indoor heat exchanger 21 passes through the accumulator 19 and is again sucked into the compressor 10 and compressed.

As shown in FIG. 11, the refrigerant valve 16 ′ is turned off during the loading operation of the compressor 10 to close the refrigerant valve 16 ′, and the refrigerant valve 16 during the unloading operation of the compressor 10. ') Is turned on to open the refrigerant valve 16'. Accordingly, the refrigerant flows in the outdoor heat exchanger 12 by bypassing the check valve 18 in the receiver 14. As a result, the pressure on the receiver 14 side is lowered, so that the shaking of the check valve 18 is improved, so that damage to the check valve 18 and valve noise can be improved.

1 is a refrigerant cycle diagram of an air conditioner according to an embodiment of the present invention.

2 is a cross-sectional view showing a loading state of the compressor applied to the air conditioner according to an embodiment of the present invention.

3 is a cross-sectional view showing an unloading state of a compressor applied to an air conditioner according to an embodiment of the present invention.

4 is a schematic control block diagram of an air conditioner according to an embodiment of the present invention.

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

FIG. 6 is a view illustrating a refrigerant flow when a compressor is loaded and operated in an air conditioner according to an embodiment of the present invention.

7 is a view showing a refrigerant flow when the compressor unloading operation in the air conditioner according to an embodiment of the present invention.

FIG. 8 is a graph showing pressure changes at both ends of the valve control and check valve of the expansion valve during the loading operation and the unloading operation of the compressor in the air conditioner according to the exemplary embodiment of the present invention.

FIG. 9 is a timing diagram illustrating an opening time of an outdoor expansion valve in an air conditioner according to an embodiment of the present invention.

10 is a refrigerant cycle diagram of an air conditioner according to another embodiment of the present invention.

11 is a control timing diagram for explaining the control of the refrigerant valve whenever the compressor is changed from the loading operation to the unloading operation in the air conditioner according to another embodiment of the present invention.

[Description of the Reference Numerals]

10: compressor 10a: PWM valve

11: four-way valve 12: outdoor heat exchanger

14: Receiver 15: Bypass piping

16: outdoor expansion valve 17: refrigerant piping

18: check valve 20: indoor expansion valve

21: indoor heat exchanger 60: control unit

Claims (13)

In an air conditioner having a receiver for storing a portion of the refrigerant circulating the outdoor heat exchanger and the indoor heat exchanger, A check valve installed in a pipe connecting the outdoor heat exchanger and the receiver to allow a refrigerant to flow in the direction from the outdoor heat exchanger to the receiver; A refrigerant valve connected in parallel with the check valve; And a control unit which opens the refrigerant valve to lower the pressure on the receiver side when the pressure at both ends of the check valve is reversed during the cooling operation. The method of claim 1, And a compressor for performing a loading operation in which the refrigerant is compressed and an unloading operation in which the refrigerant compression is stopped. And the control unit determines that the pressures at both ends of the check valve are reversed when the compressor is changed from the loading operation to the unloading operation. The method of claim 2, And the control unit opens the refrigerant valve at the time when the compressor is changed from the loading operation to the unloading operation. The method of claim 3, The refrigerant valve is a valve that can adjust the opening amount, The control unit is an air conditioner to open the opening amount of the refrigerant valve to 50% or less. The method of claim 2, And the control unit opens the refrigerant valve during the unloading operation of the compressor. The method of claim 2, The control unit is an air conditioner to open the refrigerant valve during the partial load operation section in which the compressor repeats the unloading operation and the loading operation at regular intervals. The method according to claim 5 or 6, And the refrigerant valve is an expansion valve. A refrigerant installed in a compressor for performing a loading operation in which the refrigerant is compressed and an unloading operation in which the refrigerant is stopped, a receiver storing a portion of the refrigerant circulating in the outdoor heat exchanger and the indoor heat exchanger, and a pipe connecting the outdoor heat exchanger and the receiver In the control method of the air conditioner having a check valve for flowing in the direction from the outdoor heat exchanger to the receiver, and a refrigerant valve connected in parallel with the check valve, Determining whether the compressor is changed from the loading operation to the unloading operation during a cooling operation; Controlling the air conditioner to open the refrigerant valve to lower the pressure on the receiver side when the compressor is changed from the loading operation to the unloading operation. The method of claim 8, And the compressor opens the refrigerant valve during the unloading operation. The method of claim 8, A control method of an air conditioner in which the compressor opens the refrigerant valve during a partial load operation section in which the unloading operation and the loading operation are repeated at regular intervals. The method of claim 8, And an opening amount of the refrigerant valve to 50% or less during the unloading operation of the compressor. A compressor which performs a loading operation in which the refrigerant is compressed and an unloading operation in which the refrigerant is stopped, a receiver in which a portion of the refrigerant circulating in the outdoor heat exchanger and the indoor heat exchanger is stored, and a pipe connecting the outdoor heat exchanger and the receiver In a control method of an air conditioner having a check valve for allowing refrigerant to flow in the direction from the outdoor heat exchanger to the receiver, and a refrigerant valve connected in parallel with the check valve, Determining whether the compressor is changed from a full load operation for performing only the loading operation to a partial load operation for repeating the loading operation and the unloading operation during a cooling operation; And when the compressor is changed from the full load operation to the partial load operation, opening the refrigerant valve to lower the pressure on the receiver side. The method of claim 12, Controlling the air conditioner to open the refrigerant valve at an opening amount of 50% or less during a period in which the compressor performs a partial load operation when the refrigerant valve is opened.

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