KR101585943B1 - Air conditioner and control method thereof - Google Patents

Abstract

An air conditioner capable of reducing the amount of liquid refrigerant in the receiver when the air conditioner is operated in a cooling and heating overload operation in a heat source heat pump air conditioner having a receiver and a subcooler or an economizer, And a control method thereof is disclosed. When the cooling / heating overload operation is performed, a certain number of subcoolers connected to the receiver or a motor expansion valve on the economizer side are opened to bypass the high-pressure liquid refrigerant, which is high in the receiver, to the low-pressure side so that a large amount of liquid refrigerant So that the problem of high pressure rise can be solved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an air conditioner,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a receiver and a control method thereof, and more particularly, to an air conditioner control method capable of reducing an amount of liquid refrigerant in a receiver during an air conditioning overload operation .

Generally, heat travels naturally from the high temperature side to the low temperature side, but in order to transfer heat from the low temperature side to the high temperature side, it must exert some action from the outside. This is the principle of heat pumps. The heat pump air conditioner performs a cooling or heating operation by reversibly using a transportation mechanism for heat circulated by using a refrigeration cycle consisting of compression-condensation-expansion-evaporation of a refrigerant. In order to compress refrigerant, .

Recently, a heat source heat pump air conditioner having a receiver and constituting a subcooler circuit or an economizer circuit has been introduced to improve the cooling or heating capability of such heat pump air conditioner. The heat source heat pump air conditioner uses water as a heat source for heat exchange of the refrigerant flowing in the outdoor heat exchanger, and the outdoor heat exchanger of the heat source heat pump air conditioner is generally smaller in volume than the outdoor heat exchanger of the air heat source heat pump air conditioner . Therefore, a pipe connecting the outdoor heat exchanger and the indoor heat exchanger is provided with a receiver acting as a buffer according to a change in the high pressure. The receiver is a pressure vessel that acts as a kind of buffer to change the discharge pressure. When the system has a large amount of refrigerant, it stores surplus refrigerant and separates the gaseous refrigerant and the liquid refrigerant (liquid refrigerant) from the stored refrigerant.

In addition, the heat source heat pump air conditioner uses a pulse width modulation (PWM) type capacity variable compressor to control the operation rate of the compressor. The PWM type compressor varies the operating capacity of the system according to the loading time for compressing the refrigerant and the duty ratio of the unloading time for not compressing the refrigerant.

When the water temperature of the water (heat source water) supplied to the outdoor heat exchanger is high and the operation capacity of the system is small during the cooling or heating operation in the heat source heat pump air conditioner, that is, when the cooling / heating overload operation is performed, . When a large amount of liquid refrigerant is introduced into the receiver, the space of the gaseous refrigerant, which serves as a buffer for high pressure change, is reduced, causing a problem that the operation pressure of the compressor is rapidly increased when the compressor is operated.

One aspect of the present invention provides a control method for an air conditioner capable of reducing a high pressure rise by reducing an amount of a liquid refrigerant which is insoluble in a receiver when an air conditioning overload operation is performed.

According to an aspect of the present invention, there is provided an air conditioner including: a compressor for compressing a refrigerant; An outdoor heat exchanger for exchanging the refrigerant with water; A receiver for storing a part of the refrigerant heat-exchanged with water in the outdoor heat exchanger and separating the gaseous refrigerant and the liquid refrigerant from the stored refrigerant; A sub heat exchanger for supercooling the liquid refrigerant separated from the receiver; A motor expansion valve for bypassing the liquid refrigerant separated from the receiver; A pressure sensor for sensing a high pressure side pressure of the refrigerant discharged from the compressor; A temperature sensor for sensing the temperature of the outdoor heat exchanger; A controller for controlling the opening degree of the motor-driven expansion valve so as to determine the cooling / heating overload operation using the operating capacity of the compressor, the high pressure side pressure and the temperature of the outdoor heat exchanger, and reduce the amount of the liquid refrigerant in the receiver in the cooling / .

It is preferable to use a compressor of the PWM type that adjusts the operation capacity according to the loading time for compressing the refrigerant and the unloading time for stopping the refrigerant compression.

The sub-heat exchanger preferably comprises an economizer or subcooler.

It is preferable that the electrically operated expansion valve is EEV provided on the economizer or subcooler side.

It is preferable that the pressure sensor is installed in the discharge pipe of the compressor to sense the high pressure.

It is preferable that the temperature sensor is installed in one pipe of the outdoor heat exchanger and senses the temperature at the point where the water and the refrigerant undergo heat exchange.

Preferably, the temperature sensor senses the outlet temperature of the condenser during the cooling operation and measures the temperature of the water.

The temperature sensor preferably measures the temperature of the water by sensing the evaporator inlet temperature during the heating operation.

When the operating capacity of the compressor is equal to or higher than a predetermined capacity during the cooling operation, the high pressure sensed through the pressure sensor is equal to or higher than the first pressure, and the condenser outlet temperature sensed through the temperature sensor is equal to or higher than the first temperature, So as to increase the opening degree of the electrically operated expansion valve so as to bypass the liquid refrigerant in the receiver to the low pressure side.

The first pressure is preferably 30kg / cm ² G.

The first temperature is preferably 42 degrees.

The control unit judges that the operation is a heating overload operation when the operating capacity of the compressor is equal to or higher than a predetermined capacity during the heating operation, the high pressure detected through the pressure sensor is equal to or higher than the second pressure, and the evaporator inlet temperature detected through the temperature sensor is equal to or higher than the second temperature. So as to increase the opening degree of the electrically operated expansion valve so as to bypass the liquid refrigerant in the receiver to the low pressure side.

The second pressure is preferably 35kg / cm ² G.

The second temperature is preferably 30 degrees.

It is preferable that the control unit counts the operation time for bypassing the liquid refrigerant in the receiver to the low pressure side by increasing the opening degree of the motor expansion valve and controls the opening degree of the motor expansion valve to be maintained in the previous state when the operation time has elapsed Do.

The control unit senses a high pressure that changes according to the operation of bypassing the liquid refrigerant in the receiver by increasing the opening degree of the motor-operated expansion valve through the pressure sensor, and when the changed high pressure is equal to or lower than a predetermined pressure, the opening degree of the motor- It is preferable to control so as to be maintained.

According to another aspect of the present invention, there is provided a refrigerant compressor including a compressor for compressing refrigerant, an outdoor heat exchanger for exchanging refrigerant with water, a receiver for separating the gaseous refrigerant and the liquid refrigerant by storing a part of the heat-exchanged refrigerant, And a motorized expansion valve for bypassing the liquid refrigerant, the control method comprising the steps of: sensing a high pressure side pressure of a refrigerant discharged from a compressor; Sensing the temperature of the outdoor heat exchanger; Determining whether the cooling / heating overload operation is performed using the operating capacity of the compressor, the high-pressure side pressure, and the temperature of the outdoor heat exchanger; In the case of the cooling / heating overload operation, the liquid refrigerant in the receiver is bypassed to reduce the amount of the liquid refrigerant in the receiver.

The determination as to whether or not the cooling / heating overload operation is valid is made when the operation capacity of the compressor in the cooling operation is equal to or higher than a certain capacity, the high pressure side pressure of the compressor is equal to or higher than the first pressure, and the temperature of the outdoor heat exchanger is equal to or higher than the first temperature It is preferable to judge.

The determination of the heating / overload operation is based on the assumption that when the operation capacity of the compressor during the heating operation is equal to or higher than a predetermined capacity, the high pressure side pressure of the compressor is equal to or higher than the second pressure, and the temperature of the outdoor heat exchanger is equal to or higher than the second temperature, It is preferable to judge.

To bypass the liquid refrigerant in the receiver, it is preferable that a certain number of the electrically-operated expansion valves are opened to bypass the liquid refrigerant in the receiver to the low-pressure side.

Further, a method of controlling an air conditioner according to an embodiment of the present invention includes: counting an operation time for opening a certain number of the electrically-operated expansion valves to bypass the liquid refrigerant in the receiver to the low-pressure side; And to maintain the opening degree of the electrically operated expansion valve in a previous state when the operation time has passed a predetermined time.

The control method of an air conditioner according to an embodiment of the present invention further includes detecting a high pressure side pressure that changes according to an operation of opening a motor expansion valve to bypass a liquid refrigerant in a receiver to a low pressure side; And when the detected high pressure side pressure is equal to or less than a predetermined pressure, maintaining the opening degree of the electrically operated expansion valve in the previous state.

According to an embodiment of the present invention, when a cooling / heating overload operation is performed, a certain number of subcoolers connected to a receiver or a motor expansion valve on the economizer side are opened to bypass a high-pressure liquid refrigerant high in the receiver to a low- The problem of high pressure rise can be solved.

1 is a configuration diagram of a heat source heat pump air conditioner according to an embodiment of the present invention.
Fig. 2 is a diagram showing the flow of the refrigerant during the heating operation in Fig. 1. Fig.
FIG. 3 is a configuration diagram showing the flow of refrigerant during cooling operation in FIG.
4 is a block diagram of a heat source heat pump air conditioner according to another embodiment of the present invention.
Fig. 5 is a configuration diagram showing the refrigerant flow during the heating operation in Fig.
FIG. 6 is a configuration diagram showing the flow of the refrigerant during the cooling operation in FIG.
7 is a graph illustrating a state in which the operation capacity is changed by loading and unloading the PWM type compressor in the heat source heat pump air conditioner according to the embodiment of the present invention.
FIG. 8 is a control block diagram of the heat source heat pump air conditioner according to the embodiment of the present invention shown in FIGS. 1 and 4. FIG.
FIG. 9 is a flowchart illustrating a control method in the cooling operation of the air conditioner according to the embodiment of the present invention.
FIG. 10 is a flow chart for explaining a control method in the heating operation of the air conditioner according to another embodiment of the present invention.
11 is a flow chart for explaining a control method in a cooling operation of an air conditioner according to another embodiment of the present invention.
12 is a flowchart illustrating a control method of the air conditioner in a heating operation according to another embodiment of the present invention.
13 is a configuration diagram of a geothermal source heat pump air conditioner according to another embodiment of the present invention.
14 is a configuration diagram of a geothermal source heat pump air conditioner according to another embodiment of the present invention.

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

1 is a configuration diagram of a heat source heat pump air conditioner according to an embodiment of the present invention.

1, the heat source heat pump air conditioner according to the embodiment of the present invention includes one outdoor unit 100 and a plurality of indoor units 200 connected in parallel to the outdoor unit 100. In the outdoor unit 100, (Cooling tower) 300 for supplying water (heat source water) to the outdoor heat exchanger 100 (specifically, the outdoor heat exchanger).

The outdoor unit 100 includes a compressor 10, an oil separator 25, a four-way valve 30, an outdoor heat exchanger 40, an outdoor expansion valve 45, a receiver 50, an economizer 60, 62, a solenoid valve 64, an injection pipe 66, and an accumulator 70.

The compressor 10 has two suction ports 11 and 12 and one discharge port 13. The two suction ports 11 and 12 are connected to a low pressure suction port 11 connected to a low pressure compression chamber, Pressure suction port 12, as shown in Fig. Accordingly, the compressor 10 compresses the low-temperature and low-pressure refrigerant (refrigerant) sucked into the low-pressure inlet 11 and discharges the refrigerant in the high-temperature and high-pressure state through the discharge port 13, Is a two-stage compression type compressor that receives the refrigerant bypassed from the economizer (60) in the middle pressure inlet (12).

The oil separator 25 separates the oil contained in the refrigerant discharged from the compressor 10.

The four-way valve 30 is switched to change the flow of the refrigerant discharged from the compressor 10 in accordance with the operation mode (cooling or heating). The four-way valve 30 is connected to the oil separator 20, A second port 32 connected to the outdoor heat exchanger 40 side, a third port 33 connected to the indoor unit 200 side, an accumulator And a fourth port (34) connected to the second port (70).

The outdoor heat exchanger 40 serves as an evaporator for evaporating refrigerant in a low-temperature and low-pressure liquid state to a gaseous state in a heating operation mode and a refrigerant in a high-temperature and high-pressure gaseous state in a normal- And is a main heat exchanger that performs heat exchange with water (heat source water) supplied from the hydrothermal source 300 in response to a change in enthalpy of the refrigerant.

The outdoor expansion valve 45 is an electronic expansion valve (EEV) installed in a pipe between the outdoor heat exchanger 40 and the receiver 50 to expand and expand the refrigerant.

The receiver 50 is installed in a pipe between the outdoor heat exchanger 40 and the economizer 60 to store a part of the refrigerant circulating through the outdoor heat exchanger 40 and the indoor unit 200. The receiver 50 is a pressure vessel that acts as a kind of buffer to change the discharge pressure. When the refrigerant amount is large in the system, the receiver 50 stores surplus refrigerant and separates the gaseous refrigerant and the liquid refrigerant (liquid refrigerant) from the stored refrigerant .

The economizer 60 is installed in a pipe between the receiver 50 and the indoor unit 200 to exchange heat between the refrigerant partially expanded by the electric expansion valve 62 in the liquid refrigerant discharged from the receiver 50 and the remaining liquid refrigerant, And is a sub heat exchanger securing the subcooling degree. The refrigerant expanded while passing through the electrically operated expansion valve (62) passes through the economizer (60), takes heat and is converted into a gas refrigerant.

The motorized expansion valve 62 is a valve for opening and closing the refrigerant of the economizer 60 or the refrigerant which has passed through the one side of the economizer 60 to the receiver 50, (EEV: Electronic Expansion Valve). The refrigerant expanded by the motor-operated expansion valve (62) flows into the economizer (60). The economizer 60 and the motor-operated expansion valve 62 constitute a gas-liquid separator and are installed in a liquid pipe between the indoor unit 200 and the outdoor heat exchanger 40, and are connected to the outdoor heat exchanger 40 in the indoor unit 200 during the heating operation. The gas refrigerant flows into the refrigerant flowing through the refrigerant pipe.

The solenoid valve 64 is connected to the low-pressure pipe between the economizer 60 and the accumulator 70 so that the refrigerant heat-exchanged in the economizer 60 is introduced into the accumulator 70 or the intermediate pressure inlet 12 of the compressor 10, do. When the solenoid valve 64 is opened, the refrigerant from the economizer 60 flows into the accumulator 70 having a comparatively low pressure. When the solenoid valve 64 is closed, the refrigerant from the economizer 60 is pressurized And flows into the injection pipe 66 connected to the side of the intermediate pressure suction port 12 of the relatively high compressor 10.

The injection pipe 66 branches from the piping between the economizer 60 and the accumulator 70 and is connected to the side of the intermediate pressure suction port 12 of the compressor 10. Therefore, when the solenoid valve 64 is opened, the gas refrigerant from the economizer 60 can not flow to the injection pipe 66 connected to the side of the intermediate pressure suction port 12 of the compressor 10 having a relatively high pressure, And then flows into the low accumulator 70. On the other hand, when the solenoid valve 64 is closed, the gas refrigerant from the economizer 60 flows along the injection pipe 66 and is injected toward the intermediate pressure inlet 12 of the compressor 10.

The accumulator 70 temporarily stores the refrigerant flowing into the outdoor heat exchanger 40 or the suction side of the compressor 10 from the indoor unit 200 side. In the accumulator 70, the refrigerant is separated into the gas refrigerant and the liquid refrigerant. The gas refrigerant separated from the accumulator (70) is sucked to the low pressure inlet (11) side of the compressor (10).

The outdoor unit 100 further includes a pressure sensor 82 and a temperature sensor 84.

The pressure sensor 82 is installed in the discharge pipe 13 of the compressor 10, and is installed in a high-pressure pipe through which the refrigerant is discharged from the compressor 10, and senses the high-pressure side pressure of the refrigerant.

The temperature sensor 84 is installed at one side of the outdoor heat exchanger 40 and senses the temperature at the point where heat is exchanged between the water (heat source water) and the refrigerant. In the cooling operation, And the temperature of water (heat source water) is measured by sensing the inlet temperature of the evaporator at the entrance of the outdoor heat exchanger 40 during the heating operation.

Fig. 2 is a configuration diagram showing the refrigerant flow in the heating operation in Fig. 1, and Fig. 3 is a configuration diagram showing the refrigerant flow in the cooling operation in Fig.

2, the refrigerant flows from the compressor 10 through the four-way valve 30, the indoor unit 200, the economizer 60, the receiver 50, the outdoor heat exchanger 40, the four-way valve 30, the accumulator 70, And a compressor (10) in this order.

3, the refrigerant flows from the compressor 10 through the four-way valve 30, the outdoor heat exchanger 40, the receiver 50, the economizer 60, the indoor unit 200, the four-way valve 30, the accumulator 70, And a compressor (10) in this order.

FIG. 4 is a configuration diagram of a heat source heat pump air conditioner according to another embodiment of the present invention. The same reference numerals and the same names are used for the same components as those in FIG.

4, the hydrothermal heat pump air conditioner according to another embodiment of the present invention includes one outdoor unit 400 and a plurality of indoor units 200 connected in parallel to the outdoor unit 400, 400 is connected to a water heat source 300 (cooling tower) for supplying water (heat source water) to the outdoor unit 400 (specifically, the outdoor heat exchanger).

The outdoor unit 400 includes a compressor 20, an oil separator 25, a four-way valve 30, an outdoor heat exchanger 40, an outdoor expansion valve 45, a receiver 50, a subcooler 90, (92) and an accumulator (70).

The outdoor unit 400 of FIG. 4 is the same as the outdoor unit 100 of FIG. 1 except for the compressor 20, the subcooler 90, and the electrically operated expansion valve 92, It will be omitted.

The compressor 20 has one suction port 21 and one discharge port 23 unlike the compressor 10 provided in the outdoor unit 100 of FIG. Therefore, the compressor 20 compresses the refrigerant in a low-temperature and low-pressure state, which is sucked into the suction port 21, and discharges it through the discharge port 23 in a high-temperature and high-pressure state.

The subcooler 90 is installed in the piping between the receiver 50 and the indoor unit 200 so that the subcooler 90 of the electric expansion valve 92 to heat the remaining refrigerant and the remaining liquid refrigerant to ensure supercooling of the refrigerant. The refrigerant expanded while passing through the motor-operated expansion valve 92 takes the heat while passing through the subcooler 90 and is converted into the gas refrigerant.

The motor-operated expansion valve 92 is configured to expand the refrigerant introduced into the other side of the subcooler 90 out of some refrigerant flowing into the subcooler 90 or one side of the subcooler 90 to the receiver 50 It is an electronic expansion valve (EEV). The refrigerant expanded by the motor-operated expansion valve (92) flows into the subcooler (90). The subcooler 90 and the electrically operated expansion valve 92 constitute a gas-liquid separator and are installed in a liquid pipe between the indoor unit 200 and the outdoor heat exchanger 40 and are connected to the outdoor heat exchanger 40 ) Of the refrigerant flowing through the gas refrigerant.

Comparing the supercooler 90 of Figure 4 with the economizer 60 of Figure 1 shows that when the solenoid valve 64 of Figure 1 is closed the economizer 60 has the same flow of refrigerant as the subcooler 90 do.

Fig. 5 is a diagram showing the flow of the refrigerant in the heating operation in Fig. 4, and Fig. 6 is a diagram showing the flow of the refrigerant in the cooling operation in Fig.

5, the refrigerant is circulated through the compressor 20, the four-way valve 30, the indoor unit 200, the subcooler 90, the receiver 50, the outdoor heat exchanger 40, the four-way valve 30, To the compressor (20) in this order.

6, refrigerant is circulated through the compressor 20, the four-way valve 30, the outdoor heat exchanger 40, the receiver 50, the subcooler 90, the indoor unit 200, the four-way valve 30, → compressor (20) in that order.

The compressor 10 of FIG. 1 and the compressor 20 of FIG. 4 both use a PWM variable displacement compressor, as shown in FIG.

7 is a graph illustrating a state in which the operation capacity is changed by loading and unloading the PWM type compressor in the heat source heat pump air conditioner according to the embodiment of the present invention.

In FIG. 7, a state in which the compressors 10 and 20 of the PWM system compress and discharge the refrigerant is referred to as loading, and the compressors 10 and 20 operate at 100% capacity at this time.

On the other hand, a state where the PWM type compressors 10 and 20 stop the refrigerant compression and does not discharge the refrigerant is referred to as unloading. At this time, the compressors 10 and 20 operate at 0% capacity.

 Accordingly, the high pressure rises at the time of loading and the high pressure tends to descend at the time of unloading.

As described above, the compressors 10 and 20 vary the operating capacity of the system according to the operation time (duty ratio) for determining the loading time for discharging the refrigerant and the unloading time for stopping the discharge of the refrigerant.

For example, when one cycle of the compressors 10 and 20 is 10 seconds, the refrigerant is compressed for a predetermined time (2 seconds) and the unloading operation is performed for the remaining time (8 seconds) The capacity is 20%.

As another example, when one cycle of the compressors 10 and 20 is 10 seconds, the refrigerant is compressed for a predetermined time (5 seconds) and the unloading operation is performed for the remaining time (5 seconds) The operating capacity is 50%.

As described above, the operating rate (operating capacity) of the compressors 10 and 20 varying the operating capacity of the system determines the loading time and the unloading time of the compressors 10 and 20 according to the cooling / .

FIG. 8 is a control block diagram of the heat source heat pump air conditioner according to the embodiment of the present invention shown in FIGS. 1 and 4. FIG.

In FIG. 8, the heat source heat pump air conditioner according to the embodiment of the present invention includes a microcomputer and a peripheral circuit thereof, and includes a control unit 86 for controlling the respective components of the air conditioner.

A pressure sensor 82 and a temperature sensor 84 are electrically connected to the input side of the control unit 86 and an input unit 88 for receiving an operation command from the user.

The compressor 10 and 20, the four-way valve 30, the outdoor expansion valve 45, the electric expansion valve 62 on the side of the economizer 60, the solenoid valve 64, the supercooler 90 Is electrically connected to the motor-operated expansion valve 92 of the engine.

The control unit 86 operates the four-way valve 30 in accordance with the cooling or heating operation required from the indoor unit 200 to change the refrigerant flow to the refrigerating cycle of the heating operation shown in Figs. 2 and 5, To the refrigeration cycle of the cooling operation shown in Fig.

The control unit 86 determines whether the cooling / heating overload operation is performed by using the operation ratio (operation capacity) of the compressors 10 and 20 and the sensor values of the pressure sensor 82 and the temperature sensor 84 during cooling or heating operation The opening degree of the electric expansion valve 62 on the economizer 60 side or the expansion valve 92 on the side of the subcooler 90 is adjusted so as to reduce the amount of the liquid refrigerant to be supplied to the receiver 50 And the high-pressure liquid refrigerant is bypassed to the low-pressure side.

That is, the motor-operated expansion valve 62 on the side of the economizer 60 and the motor-operated expansion valve 92 on the subcooler 90 are opened at an opening of about 100 to 300 steps at the time of normal cooling / The motor expansion valve 62 on the side of the economizer 60 and the motor expansion valve 92 on the side of the subcooler 90 are opened with an opening of about 480 steps during the cooling and heating overload operation, Thereby bypassing a large amount of the liquid refrigerant, which has been stored in the receiver 50, to the low-pressure side of the compressor 10. [

The controller 86 controls the compressors 10 and 20 sensed by the pressure sensor 82 so that the compressor 10 and 20 operate at a rate of 15% When the pressure on the high pressure side of the economizer 60 is equal to or higher than a first predetermined pressure and the outlet temperature of the condenser sensed through the temperature sensor 84 is equal to or higher than the preset first temperature, And the motor expansion valve 92 on the subcooler 90 are opened to a certain degree (about 480 steps) to reduce the amount of the liquid refrigerant which is getting into the receiver 50, thereby solving the problem of high pressure rise. At this time, the preset first pressure is 30 kg / cm ² G when R410A refrigerant is used, and 42 degrees when R410A refrigerant is used.

The controller 86 controls the pressure of the compressors 10 and 20 so that the compressors 10 and 20 are operated at a rate of 15% When the temperature of the condenser is higher than the second pressure and the condenser outlet temperature sensed through the temperature sensor 84 is equal to or higher than the second predetermined temperature, it is determined that the compressor is in the heating overload operation. Side transmission expansion valve 92 is opened at a certain degree (about 480 steps) to reduce the amount of the liquid refrigerant which is getting into the receiver 50, thereby solving the problem of high pressure rise. At this time, the preset second pressure is 35 kg / cm ² G when R410A refrigerant is used, and the second temperature is 30 degrees when R410A refrigerant is used.

The control unit 86 judges that the engine is in the heating / overload operation mode and the bypass valve 60 opens the motor expansion valve 62 on the side of the economizer 60 and the motor expansion valve 92 on the subcooler 90 side by a certain degree (about 480 steps) The opening degree of the electric expansion valve 62 on the side of the economizer 60 and the opening degree of the electric expansion valve 92 on the subcooler 90 are set to a certain degree (about 480 steps) (About 100 to 300 steps) from the previous normal operating state to perform the original operation of forming the low temperature refrigerant at the side of the economizer 60 and the side of the subcooler 90. [

The control unit 86 is also provided for feeding back the electric expansion valve 62 on the economizer 60 side and the electric expansion valve 92 on the subcooler 90 side to the opening degree (about 100 to 300 steps) (10, 20) sensed by the pressure sensor 82, in addition to performing the bypass operation of reducing the amount of the liquid refrigerant to be supplied to the receiver 50 for a predetermined period of time (about 3 minutes) The opening degree of the electric expansion valve 62 on the economizer 60 side and the electric expansion valve 92 on the subcooler 90 side are set to a predetermined degree (About 100 to 300 steps) from the previous normal operating state (about 480 steps) to perform the original operation of forming the low temperature refrigerant on the side of the economizer 60 and the subcooler 90 side. The predetermined third pressure is a high pressure side pressure under cooling operation 30kg / cm ² G constant pressure at a falling value or less (for example, 25kg / cm ² G), a predetermined fourth pressure is a high pressure during the heating operation side And the pressure drops from 35 kg / cm ² G to a certain pressure (for example, 30 kg / cm ² G) or less.

Hereinafter, the operation and effect of the air conditioner and the control method thereof will be described.

FIG. 9 is a flowchart illustrating a control method in the cooling operation of the air conditioner according to the embodiment of the present invention.

9, the control unit 86 receives the cooling request capability from the indoor unit 200 (500), switches the four-way valve 30 to change the flow of the refrigerant as shown in FIG. 3 and FIG. 6 The cooling operation is started (502).

7, the control unit 86 supplies power to the compressors 10 and 20 to determine a loading time for discharging the refrigerant and an unloading time for stopping the discharge of the refrigerant, (Operation capacity) of the fuel cell stacks 10 and 20 (504).

The control unit 86 determines whether the operation rate of the compressors 10 and 20 is equal to or greater than the predetermined operation capacity (about 15%) with respect to the total operation capacity of the compressors 10 and 20 If the operation rate is more than the constant operation capacity (about 15%) compared with the total operation capacity, it is judged that the operation capacity of the system is small.

The controller 86 detects the high pressure side pressure of the refrigerant discharged from the compressors 10 and 20 through the pressure sensor 82 provided in the discharge pipe 13 of the compressors 10 and 20 (508).

Accordingly, the control unit 86 determines whether the high pressure side pressure of the compressors 10 and 20 sensed through the pressure sensor 82 is equal to or higher than the preset first pressure, When the pressure is equal to or higher than the first pressure, the control unit 86 senses the outlet side temperature of the outdoor heat exchanger 40 through which the water (heat source water) and the refrigerant undergo heat exchange, that is, the condenser outlet temperature through the temperature sensor 84 ).

The control unit 86 determines whether the condenser outlet temperature sensed through the temperature sensor 84 is equal to or higher than a predetermined first temperature in step 514. If the condenser outlet temperature is equal to or higher than the first temperature, It is judged to be an overload operation.

In the cooling overload operation, when the water temperature of the water (heat source water) supplied to the outdoor heat exchanger 40 is high while the operation capacity of the system is low, a large amount of refrigerant is accumulated in the receiver 50, 20) is increased. If a large amount of the liquid refrigerant becomes high in the receiver 50 due to the cooling overload operation, the space of the gaseous refrigerant in the receiver 50, which serves as a buffer for the high pressure change, is reduced and the operation of the compressors 10 and 20 The buffer space for the change in capacitance or the high pressure change caused by the loading of the compressors 10 and 20 is reduced or the instantaneous high pressure rise occurs when the receiver 50 is fully charged.

The control unit 86 increases the opening degree of the motor expansion valve 62 on the economizer 60 side and the expansion valve 92 on the supercooler 90 side to a predetermined degree (about 480 steps) (518). By bypassing the high-pressure liquid refrigerant to the low-pressure side, a bypass operation is performed to reduce the amount of the high-temperature liquid refrigerant in the receiver (518).

When the amount of the liquid refrigerant that is in the receiver 50 is reduced in accordance with the bypass operation, the controller 86 controls the operation of bypassing the liquid refrigerant, which has been supplied to the receiver 50, to the low pressure side for a predetermined time , 3 minutes) has elapsed (520).

As a result of the determination in step 520, if it is determined that the operation for bypassing the liquid refrigerant to the low pressure side by the receiver 50 has not elapsed for a predetermined time, the flow returns to step 518 to continue the bypass operation.

If it is determined in step 520 that the operation of bypassing the liquid refrigerant to the low pressure side of the receiver 50 has elapsed after a certain period of time has elapsed, the motor-operated expansion valve 62 on the side of the economizer 60 and the motor- The opening degree of the expansion valve 92 is maintained at a predetermined opening degree (about 480 steps), the opening degree of the previous normal operating state (about 100 to 300 steps) (522), and the cooling operation is performed (524).

On the other hand, if it is determined in step 506 that the operation ratio of the compressors 10 and 20 is not equal to or greater than the predetermined operation capacity (about 15%) with respect to the total operation capacity, the process proceeds to step 522 where the electric expansion valve 62) and the opening degree of the subcooler 90 side motor-operated expansion valve 92 to the opening degree of the normal operation state (about 100 to 300 steps), and performs the cooling operation (524).

If it is determined in step 510 that the high-pressure side pressure of the compressors 10 and 20 is not equal to or higher than the first pressure, the flow proceeds to step 522 to move the motor expansion valve 62 on the economizer 60 side to the subcooler 90 side The opening degree of the motor-operated expansion valve 92 is maintained at the opening degree (about 100 to 300 steps) of the normal operating state, and the cooling operation is performed (524).

If it is determined in step 514 that the outlet temperature of the condenser is not equal to or higher than the first temperature, the process proceeds to step 522 so that the electric expansion valve 62 on the economizer 60 side and the electric expansion valve 92 on the subcooler 90 side The opening degree is maintained at the opening degree of the normal operating state (about 100 to 300 steps), and the cooling operation is performed (524).

FIG. 10 is a flow chart for explaining a control method in the heating operation of the air conditioner according to another embodiment of the present invention.

10, the control unit 86 receives the heating request capability from the indoor unit 200 (600), switches the four-way valve 30 to change the flow of the refrigerant as shown in FIGS. 2 and 5 The heating operation is started (602).

The control unit 86 supplies power to the compressors 10 and 20 to determine a loading time for discharging the refrigerant and an unloading time for stopping the discharge of the refrigerant, (604) the operation rates of the first and second actuators (10, 20).

The control unit 86 determines whether the operation rate of the compressors 10 and 20 is equal to or greater than the predetermined operation capacity (about 15%) with respect to the total operation capacity (606) If the operation capacity is more than the fixed operation capacity (approx. 15%), it is judged that the system operation capacity is small.

The controller 86 detects the high pressure side pressure of the refrigerant discharged from the compressors 10 and 20 through the pressure sensor 82 provided in the discharge pipe 13 of the compressors 10 and 20 (608).

Accordingly, the control unit 86 determines whether the high pressure side pressure of the compressors 10 and 20 sensed through the pressure sensor 82 is equal to or higher than a preset second pressure (610) When the pressure is equal to or higher than the second pressure, the control unit 86 senses the inlet side temperature of the outdoor heat exchanger 40 through which the water (heat source water) and the refrigerant undergo heat exchange, that is, the evaporator inlet temperature through the temperature sensor 84 ).

The control unit 86 determines whether the evaporator inlet temperature sensed through the temperature sensor 84 is equal to or higher than a predetermined second temperature in step 614. If the evaporator inlet temperature is equal to or higher than the second temperature, It is judged to be an overload operation.

In the heating overload operation, when the water temperature of the water (heat source water) supplied to the outdoor heat exchanger 40 is high while the operation capacity of the system is low during the heating operation, a large amount of refrigerant becomes high in the receiver 50 , And the discharge pressure (condensation pressure) of the compressors 10 and 20 is increased. If a large amount of liquid refrigerant is accumulated in the receiver 50 due to the heating overload operation, the space of the gaseous refrigerant of the receiver 50, which serves as a buffer for the high pressure change, is reduced, and the operation of the compressors 10 and 20 The buffer space for the change in capacitance or the high pressure change caused by the loading of the compressors 10 and 20 is reduced or the instantaneous high pressure rise occurs when the receiver 50 is fully charged.

The controller 86 increases the opening degree of the motor expansion valve 62 on the economizer 60 side and the motor expansion valve 92 on the subcooler 90 side to a predetermined degree (about 480 steps) (618). By bypassing the high-pressure liquid refrigerant to the low-pressure side, a bypass operation is performed to reduce the amount of the liquid refrigerant that is being supplied to the receiver (618).

When the amount of the liquid refrigerant that is in the receiver 50 is reduced in accordance with the bypass operation, the controller 86 controls the operation of bypassing the liquid refrigerant, which has been supplied to the receiver 50, to the low pressure side for a predetermined time , 3 minutes) has elapsed (620).

As a result of the determination in step 620, if the operation for bypassing the liquid refrigerant to the low pressure side by the receiver 50 has not elapsed for a predetermined time, the flow returns to step 618 to continue the bypass operation.

If it is determined in step 620 that the operation of bypassing the liquid refrigerant to the low pressure side of the receiver 50 has elapsed after a certain period of time has elapsed, the motor-operated expansion valve 62 on the economizer 60 side and the motor- The opening degree of the expansion valve 92 is maintained at a predetermined opening degree (about 480 steps), the opening degree of the previous normal operating state (about 100 to 300 steps) (622), and the heating operation is performed (624).

If it is determined in step 606 that the operation ratio of the compressors 10 and 20 is not equal to or greater than the predetermined operation capacity (about 15%) with respect to the total operation capacity, the process proceeds to step 622 where the electric expansion valve 62) and the opening degree of the subcooler 90 side electrically operated expansion valve 92 to the opening degree of the normal operation state (about 100 to 300 steps), and performs the heating operation (624).

If it is determined in step 610 that the high-pressure side pressure of the compressors 10 and 20 is not equal to or higher than the second pressure, the process proceeds to step 622 where the motor expansion valve 62 on the economizer 60 side and the super- The opening degree of the electrically operated expansion valve 92 is maintained at the opening degree of the normal operating state (about 100 to 300 steps), and the heating operation is performed (624).

If it is determined in step 614 that the evaporator inlet temperature is not equal to or higher than the second temperature, the flow advances to step 622 so that the electric expansion valve 62 on the economizer 60 side and the electric expansion valve 92 on the subcooler 90 side The opening degree is maintained at the opening degree (about 100 to 300 steps) of the normal operating state, and the heating operation is performed (624).

FIG. 11 is a flow chart for explaining a control method in a cooling operation of an air conditioner according to another embodiment of the present invention, wherein the same parts as those in FIG. 9 will be described as redundant as possible.

11, the control unit 86 receives the cooling request capability from the indoor unit 200 (700), switches the four-way valve 30 to change the flow of the refrigerant as shown in FIG. 3 and FIG. 6 The cooling operation is started (702).

Then, the control unit 86 adjusts the operation rate of the compressors 10 and 20 according to the cooling demand capability (704) as shown in FIG.

The control unit 86 determines whether the operation ratio of the compressors 10 and 20 is equal to or greater than the predetermined operation capacity (about 15%) with respect to the total operation capacity (706) If the operation capacity is more than the fixed operation capacity (approx. 15%), it is judged that the system operation capacity is small.

If the operating capacity of the system is small, the control unit 86 senses the high-pressure side pressure of the refrigerant discharged from the compressors 10 and 20 through the pressure sensor 82 (708).

Accordingly, the control unit 86 determines whether the high pressure side pressure of the compressors 10 and 20 sensed through the pressure sensor 82 is equal to or higher than the first pressure level 710 and the high pressure side pressure of the compressors 10 and 20 The control unit 86 senses the outlet side temperature of the outdoor heat exchanger 40, that is, the condenser outlet temperature through the temperature sensor 84 (712).

Accordingly, the control unit 86 determines whether the condenser outlet temperature sensed through the temperature sensor 84 is equal to or higher than the first temperature (714). If the condenser outlet temperature is equal to or higher than the first temperature, the control unit 86 performs the cooling overload operation .

The control unit 86 increases the opening degree of the motor expansion valve 62 on the economizer 60 side and the expansion valve 92 on the supercooler 90 side to a predetermined degree (about 480 steps) (718), bypassing the high-pressure liquid refrigerant to the low-pressure side to reduce the amount of the liquid refrigerant that is in the receiver (50).

When the amount of the liquid refrigerant in the receiver 50 is reduced by the bypass operation as described above, the controller 86 controls the pressure sensor 82 to change the pressure on the high pressure side of the refrigerant discharged from the compressors 10 and 20 (720).

The control unit 86 determines whether the pressure on the high pressure side of the compressors 10 and 20 sensed by the pressure sensor 82 falls below the third pressure or not 722 and determines whether the pressure on the high pressure side of the compressors 10 and 20 If the pressure does not fall below the third pressure, the flow returns to step 718 to continue the bypass operation.

On the other hand, if it is determined in step 722 that the high-pressure side pressure of the compressors 10 and 20 is lower than the third pressure due to the operation of bypassing the liquid refrigerant that has been drawn into the receiver 50 to the low pressure side, The opening degree of the valve 62 and the expansion valve 92 on the side of the supercooler 90 is maintained at a predetermined opening degree (about 480 steps) to an opening degree (about 100 to 300 steps) of the previous normal operating state (724) (726).

On the other hand, if it is determined in step 706 that the operation ratio of the compressors 10 and 20 is not equal to or greater than the predetermined operation capacity (about 15%) with respect to the total operation capacity, the process proceeds to step 724 where the electric expansion valve 62) and the opening degree of the subcooler 90 side electrically operated expansion valve 92 are maintained at an opening degree (about 100 to 300 steps) of a normal operation state and the cooling operation is performed (726).

If it is determined in step 710 that the high-pressure side pressure of the compressors 10 and 20 is not equal to or higher than the first pressure, the process advances to step 724 so that the motor expansion valve 62 on the economizer 60 side and the subcooler 90 side The opening degree of the motor-operated expansion valve 92 is maintained at the opening degree of the normal operating state (about 100 to 300 steps), and the cooling operation is performed (726).

If it is determined in step 714 that the outlet temperature of the condenser is not equal to or higher than the first temperature, the flow advances to step 724 so that the ratio between the electric expansion valve 62 on the economizer 60 side and the electric expansion valve 92 on the subcooler 90 side The opening degree is maintained at the opening degree of the normal operating state (about 100 to 300 steps), and the cooling operation is performed (726).

FIG. 12 is a flow chart for explaining a control method in the heating operation of the air conditioner according to another embodiment of the present invention, wherein the same parts as those in FIG. 10 will be described as redundant as possible.

12, the control unit 86 receives the heating request capability from the indoor unit 200 (800), switches the four-way valve 30 to change the flow of the refrigerant as shown in FIGS. 2 and 5 The heating operation is started (802).

The control unit 86 adjusts the operation rates of the compressors 10 and 20 as shown in FIG. 7 according to the cooling request capability (804).

The control unit 86 determines whether the operation rate of the compressors 10 and 20 is equal to or greater than the predetermined operation capacity (about 15%) with respect to the total operation capacity (806) If the operation capacity is more than the fixed operation capacity (approx. 15%), it is judged that the system operation capacity is small.

If the operating capacity of the system is small, the control unit 86 senses the high pressure side pressure of the refrigerant discharged from the compressors 10 and 20 through the pressure sensor 82 (808).

Accordingly, the control unit 86 determines whether the high pressure side pressure of the compressors 10 and 20 sensed through the pressure sensor 82 is equal to or higher than the second pressure (810), and the high pressure side pressure of the compressors 10 and 20 The control unit 86 senses the inlet side temperature of the outdoor heat exchanger 40, that is, the evaporator inlet temperature through the temperature sensor 84 (812).

The controller 86 determines whether the evaporator inlet temperature sensed by the temperature sensor 84 is equal to or higher than the second temperature (814). If the evaporator inlet temperature is equal to or higher than the second temperature, the controller 86 controls the heating overload operation .

The control unit 86 increases the opening degree of the motor expansion valve 62 on the economizer 60 side and the motor expansion valve 92 on the subcooler 90 side to a predetermined degree (about 480 steps) (816). By bypassing the high-pressure liquid refrigerant to the low-pressure side, a bypass operation is performed to reduce the amount of the liquid refrigerant becoming insoluble in the receiver (818).

When the amount of the liquid refrigerant in the receiver 50 is reduced by the bypass operation as described above, the controller 86 controls the pressure sensor 82 to change the pressure on the high pressure side of the refrigerant discharged from the compressors 10 and 20 (820).

The control unit 86 determines whether the pressure on the high pressure side of the compressors 10 and 20 sensed by the pressure sensor 82 falls below the fourth pressure 822 and determines whether the pressure on the high pressure side of the compressors 10 and 20 If the pressure does not drop below the fourth pressure, the process returns to step 818 to continue the bypass operation.

On the other hand, if it is determined in step 822 that the high-pressure side pressure of the compressors 10 and 20 is lower than the fourth pressure due to the operation of bypassing the liquid refrigerant which has been drawn into the receiver 50 to the low pressure side, The opening degree of the valve 62 and the electrically operated expansion valve 92 on the subcooler 90 is maintained at a predetermined opening degree (about 480 steps) to an opening degree (about 100 to 300 steps) of the previous normal operating state (824) (826).

On the other hand, if it is determined in step 806 that the operation ratio of the compressors 10 and 20 is not equal to or greater than the predetermined operation capacity (about 15%) with respect to the total operation capacity, the process proceeds to step 824 where the electric expansion valve 62) and the opening degree of the subcooler 90 side motor-operated expansion valve 92 to the opening degree of the normal operation state (about 100 to 300 steps), and performs the heating operation (826).

If it is determined in step 810 that the high pressure side pressure of the compressors 10 and 20 is not equal to or higher than the second pressure, the process proceeds to step 824 where the motor expansion valve 62 on the economizer 60 side and the subcooler 90 side The opening degree of the motor-operated expansion valve 92 is maintained at the opening degree of the normal operating state (about 100 to 300 steps), and the heating operation is performed (826).

If it is determined in step 814 that the evaporator inlet temperature is not equal to or higher than the second temperature, the process proceeds to step 824 to determine whether or not the electric expansion valve 62 on the economizer 60 side and the electric expansion valve 92 on the subcooler 90 side The opening degree is maintained at the opening degree of the normal operating state (about 100 to 300 steps), and the heating operation is performed (826).

In the embodiment of the present invention, the heat pump air conditioner of the water heat source 300 system using water (heat source water) as the heat source for heat-exchanging the refrigerant flowing in the outdoor heat exchanger 40 is described as an example. However, It is needless to say that the same objects and effects as those of the present invention can also be achieved in a heat pump air conditioner of a geothermal source 350 system using geothermal heat as a heat source for heat-exchanging the refrigerant flowing through the outdoor heat exchanger 40.

Examples of the geothermal source heat pump air conditioner are shown in Figs. 13 and 14. Fig.

13 is a configuration diagram of a geothermal source heat pump air conditioner according to another embodiment of the present invention.

13, the geothermal source heat pump air conditioner according to an embodiment of the present invention includes one outdoor unit 100 and a plurality of indoor units 200 connected in parallel to the outdoor unit 100. In the outdoor unit 100, A geothermal heat source 350 for supplying geothermal heat to the outdoor heat exchanger 100 (specifically, the outdoor heat exchanger) is connected.

The geothermal source heat pump air conditioner of FIG. 13 is the same as the entire configuration of the hydrothermal heat pump air conditioner of FIG. 1 except that the geothermal heat is used as a heat source for heat-exchanging the refrigerant flowing into the outdoor heat exchanger 40, It is omitted.

14 is a configuration diagram of a geothermal source heat pump air conditioner according to another embodiment of the present invention.

14, the geothermal source heat pump air conditioner according to the embodiment of the present invention includes one outdoor unit 400 and a plurality of indoor units 200 connected in parallel to the outdoor unit 400. In the outdoor unit 400, A geothermal heat source 350 for supplying geothermal heat to the outdoor heat exchanger 400 (specifically, the outdoor heat exchanger) is connected.

The geothermal source heat pump air conditioner of FIG. 14 is the same as the entire configuration of the hydrothermal heat pump air conditioner of FIG. 4 except that the geothermal heat is used as a heat source for heat-exchanging the refrigerant flowing into the outdoor heat exchanger 40, It is omitted.

10, 20: compressor 30: four-way valve
40: outdoor heat exchanger 50: receiver
60: Economizer 62: Electric expansion valve
70: accumulator 82: pressure sensor
84: Temperature sensor 86:
90: supercooler 92: electric expansion valve
100, 400: outdoor unit 200: indoor unit
300: Water heat source 350: Geothermal heat source

Claims (22)

A compressor for compressing the refrigerant;
An outdoor heat exchanger for heat-exchanging the refrigerant with water;
A receiver for storing a part of the refrigerant heat-exchanged with water in the outdoor heat exchanger and separating the gaseous refrigerant and the liquid refrigerant from the stored refrigerant;
A sub heat exchanger for subcooling the liquid refrigerant separated from the receiver;
An electrically operated expansion valve for bypassing the liquid refrigerant separated from the receiver;
A pressure sensor for sensing a high pressure side pressure of the refrigerant discharged from the compressor;
A temperature sensor for sensing the temperature of the outdoor heat exchanger;
Wherein the control unit determines the cooling / heating overload operation using the operation capacity of the compressor, the high pressure side pressure, and the temperature of the outdoor heat exchanger, and determines the opening degree of the motor expansion valve to decrease the amount of liquid refrigerant in the receiver in the cooling / And a controller for controlling the air conditioner. The method according to claim 1,
Wherein the compressor is a PWM type compressor that adjusts the operation capacity according to a loading time for compressing the refrigerant and an unloading time for stopping the refrigerant compression. The method according to claim 1,
Wherein the sub-heat exchanger includes an economizer or a subcooler. The method of claim 3,
Wherein the electrically operated expansion valve is an EEV provided on the economizer or subcooler side. The method according to claim 1,
Wherein the pressure sensor is installed in a discharge pipe of the compressor and senses a high pressure. 6. The method of claim 5,
Wherein the temperature sensor is installed in one pipe of the outdoor heat exchanger and senses a temperature at a point where the water and the refrigerant undergo heat exchange. The method according to claim 6,
Wherein the temperature sensor measures a temperature of the water by sensing a condenser outlet temperature during a cooling operation. The method according to claim 6,
Wherein the temperature sensor senses an evaporator inlet temperature during a heating operation and measures the temperature of the water. 8. The method of claim 7,
Wherein when the operating capacity of the compressor is equal to or higher than a predetermined capacity during the cooling operation, the high pressure sensed through the pressure sensor is equal to or higher than the first pressure, and the condenser outlet temperature sensed through the temperature sensor is equal to or higher than the first temperature, And increases the opening degree of the electrically operated expansion valve so as to bypass the liquid refrigerant in the receiver to the low pressure side. 10. The method of claim 9,
Wherein the first pressure is 30 kg / cm < ² > G. 10. The method of claim 9,
Wherein the first temperature is 42 degrees. 9. The method of claim 8,
Wherein when the operating capacity of the compressor is equal to or higher than a predetermined capacity during a heating operation, the high pressure sensed through the pressure sensor is equal to or higher than a second pressure, and the evaporator inlet temperature sensed through the temperature sensor is equal to or higher than a second temperature, And increases the opening degree of the electrically operated expansion valve so as to bypass the liquid refrigerant in the receiver to the low pressure side. 13. The method of claim 12,
It said second pressure is 35kg / cm ² G group of the air conditioner. 13. The method of claim 12,
Wherein the second temperature is 30 degrees. The method according to claim 9 or 12,
The control unit may increase an opening degree of the electrically operated expansion valve to count an operation time for bypassing the liquid refrigerant in the receiver to the low pressure side, and maintain the opening degree of the electrically operated expansion valve at a previous state The air conditioner comprising: The method according to claim 9 or 12,
Wherein the control unit senses the high pressure which changes according to the operation of bypassing the liquid refrigerant in the receiver to the low pressure side by increasing the opening degree of the motor expansion valve through the pressure sensor and when the changed high pressure is equal to or lower than a constant pressure, And controls the opening of the valve to be maintained in a previous state. A sub-heat exchanger for subcooling the liquid refrigerant; a heat exchanger for separating the gaseous refrigerant from the liquid refrigerant; a sub-heat exchanger for subcooling the liquid refrigerant; A control method for an air conditioner provided with a motor-operated expansion valve for bypassing,
Sensing a high pressure side pressure of the refrigerant discharged from the compressor;
Sensing a temperature of the outdoor heat exchanger;
Determining whether the cooling / heating overload operation is performed using the operation capacity of the compressor, the high pressure side pressure, and the temperature of the outdoor heat exchanger;
And the amount of liquid refrigerant in the receiver is reduced by bypassing the liquid refrigerant in the receiver in the cooling / heating overload operation. 18. The method of claim 17,
The determination as to whether the heating /
Wherein the control unit determines that the operation mode of the air conditioner is a cooling overload operation when the operation capacity of the compressor is equal to or higher than a predetermined capacity during the cooling operation and the pressure on the high pressure side of the compressor is equal to or higher than the first pressure and the temperature of the outdoor heat exchanger is equal to or higher than the first temperature Control method. 18. The method of claim 17,
The determination as to whether the heating /
When the operating capacity of the compressor is equal to or higher than a predetermined capacity at the time of heating operation, the high pressure side pressure of the compressor is equal to or higher than the second pressure, and the temperature of the outdoor heat exchanger is equal to or higher than the second temperature, Control method. 18. The method of claim 17,
By bypassing the liquid refrigerant in the receiver,
And the liquid refrigerant in the receiver is bypassed to the low-pressure side by opening a certain number of the electrically-operated expansion valves. 21. The method of claim 20,
A counter for counting an operating time for opening a certain number of the electrically operated expansion valves and bypassing the liquid refrigerant in the receiver to a low pressure side;
Further comprising maintaining the opening degree of the electrically operated expansion valve in a previous state when the operation time has passed a predetermined time. 21. The method of claim 20,
Sensing the high-pressure side pressure that changes according to an operation of opening a certain number of the electrically-operated expansion valves and bypassing the liquid refrigerant in the receiver to the low-pressure side;
Further comprising maintaining the opening degree of the electrically operated expansion valve in a previous state when the detected high pressure side pressure is equal to or lower than a predetermined pressure.

Images