KR20240036780A - An air conditioner and a control method the same - Google Patents

Abstract

The present invention relates to an air conditioner and a control method thereof.
An air conditioner according to an embodiment of the present invention includes a compressor that compresses a refrigerant; outdoor heat exchanger; and indoor heat exchanger; a gas-liquid separator that separates abnormal refrigerant condensed in the outdoor heat exchanger or the indoor heat exchanger into liquid refrigerant and gaseous refrigerant; and a first connection pipe connecting the outdoor heat exchanger and the gas-liquid separator and on which a first valve is installed; and a second connection pipe that connects the indoor heat exchanger and the gas-liquid separator and includes a second valve, wherein at least one of the first connection pipe and the second connection pipe branches the refrigerant to the gas-liquid separator. branch; a liquid pipe branching from the branch and sucking the liquid refrigerant inside the gas-liquid separator; and a branch pipe discharging refrigerant into the gas-liquid separator.

Description

Air conditioner and its control method {An air conditioner and a control method the same}

The present invention relates to an air conditioner and a control method including a gas-liquid separator, and in particular to an air conditioner including a gas-liquid separator that can resolve refrigerant imbalance by improving the flow of refrigerant flowing into the gas-liquid separator and its control method. It's about.

An air conditioner is a home appliance that maintains indoor air in the optimal condition depending on the use and purpose. For example, in the summer, the indoor space is adjusted to a cool air-conditioning state, and in the winter, the indoor space is adjusted to a warm heating state, the indoor humidity is adjusted, and the indoor air is adjusted to a pleasant clean state.

As convenience products such as air conditioners are gradually expanded and used, consumers are demanding products with high energy use efficiency, improved performance, and ease of use.

Depending on whether the indoor and outdoor units are separated, these air conditioners can be divided into separate air conditioners in which the indoor and outdoor units are separate, and integrated air conditioners in which the indoor and outdoor units are combined into one device.

Meanwhile, depending on how the air conditioner is installed, it can be divided into wall-mounted air conditioners and frame-type air conditioners designed to be mounted on the wall, and slim-type air conditioners designed to be installed in the living room.

In addition, depending on the capacity of the indoor unit, a single-type air conditioner is configured with a capacity that can drive one indoor unit and is designed to be used in narrow places such as a home, and a medium-to-large air conditioner is configured with a very large capacity to be used in a company or restaurant. It can be divided into tiles and multi-air conditioners with a capacity that can sufficiently operate multiple indoor units.

Such an air conditioner includes a gas-liquid separator that filters liquid refrigerant from the refrigerant and supplies it to the compressor, thereby preventing a significant decrease in compression efficiency due to liquid refrigerant flowing into the compressor.

However, according to the conventional air conditioner including a general gas-liquid separator, the separation of liquid refrigerant and gaseous refrigerant in the gas-liquid separator is not done well, resulting in refrigerant imbalance, so even though it has excellent heat transfer efficiency locally, overall performance and efficiency are low. There are problems in that the volume of the gas-liquid separator is large and the structure is complex, so the manufacturing cost increases and the internal pressure loss increases.

In addition, a dual flow path is generally applied to the front of the receiver to ensure that the vapor phase and liquid refrigerant within the receiver are well separated, but a separate subcooler and a bypass pipe for the vapor phase refrigerant must be provided, which complicates the configuration and increases costs. there is.

The prior literature techniques are as follows.

(1) Publication number (publication date): 10-2011-0040997 (2011.04.29)

(2) Title of invention: Gas-liquid separator and air conditioner including the same

The present invention was proposed to solve the above problems of the previously proposed methods, and is an air conditioner and air conditioner including a gas-liquid separator that can resolve refrigerant imbalance by improving the flow of refrigerant flowing into the gas-liquid separator. The purpose is to provide a method of controlling the machine.

The air conditioner according to this embodiment includes a compressor that compresses refrigerant; outdoor heat exchanger; and indoor heat exchanger; a gas-liquid separator that separates abnormal refrigerant condensed in the outdoor heat exchanger or the indoor heat exchanger into liquid refrigerant and gaseous refrigerant; and a first connection pipe connecting the outdoor heat exchanger and the gas-liquid separator and on which a first valve is installed; and a second connection pipe that connects the indoor heat exchanger and the gas-liquid separator and includes a second valve, wherein at least one of the first connection pipe and the second connection pipe branches the refrigerant to the gas-liquid separator. branch; a liquid pipe branching from the branch and sucking the liquid refrigerant inside the gas-liquid separator; and a branch pipe discharging refrigerant into the gas-liquid separator.

The branch part includes a first branch part branched from the first connection pipe and a second branch part branched from the second connection pipe, and the liquid pipe includes a first liquid pipe branched from the first branch part and It may include a second liquid pipe branched from the second branch part, and the branch pipe may include a first branch pipe branched from the first branch part and a second branch pipe branched from the second branch part. .

The first and second valves may include an expansion valve whose opening can be adjusted to depressurize the condensed refrigerant.

A first check valve provided in the first branch pipe and controlling the flow of refrigerant; And it is provided in the second branch pipe, and may further include a second check valve that regulates the flow of refrigerant.

A third check valve provided in the first liquid pipe and controlling the flow of refrigerant; And it is provided in the second liquid pipe and may further include a fourth check valve that regulates the flow of refrigerant.

It may include an injection pipe for introducing the gaseous refrigerant separated in the gas-liquid separator into the compressor, and the injection pipe may include a third valve that regulates the flow of the gaseous refrigerant.

The extension pipe may be connected to the medium pressure end of the compressor.

The gas-liquid separator includes a gas-liquid separator main body having a vertical height, and the first branch pipe and the second branch pipe allow the condensed refrigerant to flow into the interior of the gas-liquid separator through the top of the gas-liquid separator main body. The branch pipe, the first liquid pipe, and the second liquid pipe may be connected to the upper surface of the gas-liquid separator.

The first branch pipe and the second branch pipe may include a bent portion that is bent to discharge the refrigerant toward the inner wall of the gas-liquid separator.

The bent portion may be bent between 30 and 90 degrees toward the inner peripheral surface of the gas-liquid separator.

A third connection pipe connecting the outdoor heat exchanger and the flow switching valve; A fourth connection pipe connecting the indoor heat exchanger and the flow switching valve; It may further include a fifth connection pipe and a sixth connection pipe respectively connecting the flow conversion valve and the compressor.

A method of controlling an air conditioner according to an embodiment of the present invention includes inputting an operation mode and operating a compressor; determining whether the rotation speed of the compressor is greater than or equal to a set rotation speed; When it is determined that the rotation speed of the compressor is greater than the set rotation speed, comparing the subcooling degree, which is the difference between the saturated condensation temperature of the condenser and the current condensation temperature, with the target subcooling degree, and comparing the current subcooling degree with the target subcooling degree, and adjusting the opening degree of a valve adjacent to the condenser.

After the step of adjusting the opening degree of the valve adjacent to the condenser is performed, the step of comparing the current discharge temperature on the outlet side of the compressor with the target discharge temperature is further included, and according to the comparison result, the opening degree of the valve adjacent to the evaporator is adjusted. It may include an adjustment step.

While performing the step of adjusting the valve adjacent to the evaporator according to the comparison between the current discharge temperature of the compressor and the target discharge temperature, the step of comparing whether the current operation time of the compressor is a set operation time may be further included.

If the current operation time is greater than or equal to the set operation time, the method may include expanding the opening degree of the third valve.

After the step of expanding the opening degree of the third valve, if the amount of change in the current discharge temperature for a certain period of time is greater than a specific amount of change, the step of closing the third valve may be included.

According to the air conditioner and the control method of the air conditioner according to the embodiment of the present invention, the first connection pipe and the second connection pipe connected to the gas-liquid separator each have a liquid pipe and a branch pipe, so that the gas-liquid separator inside the gas-liquid separator It has the advantage of being easy to separate the refrigerant and gaseous refrigerant.

In addition, by providing a separate injection pipe connecting the gas-liquid separator and the compressor, gaseous refrigerant that has not passed through the evaporator flows into the compressor, thereby improving compressor efficiency.

In addition, by controlling the opening degree of the first valve during cooling operation, the degree of subcooling of the condenser is controlled, thereby lowering the dryness of the medium pressure cycle and increasing cooling efficiency.

In addition, by controlling the opening degree of the second valve during cooling operation, the discharge temperature can be easily adjusted by controlling the flow rate of the evaporator.

1 is a diagram illustrating a refrigerant system of a gas-liquid separator according to an embodiment of the present invention.
Figure 2 is an enlarged view of portion A of Figure 1.
Figure 3 is a diagram showing the refrigerant flow of an air conditioner according to an embodiment of the present invention during cooling operation.
Figure 4 is a diagram showing a control method of an air conditioner according to an embodiment of the present invention during cooling operation.
Figure 5 is a diagram showing the refrigerant flow of an air conditioner according to an embodiment of the present invention during heating operation.
Figure 6 is a diagram showing a control method of an air conditioner according to an embodiment of the present invention during heating operation.
Figure 7 is a diagram comparing the PH diagram when the opening degree of the valve of the air conditioner according to the present invention is changed.
Figure 8 is a diagram showing several examples of a gas-liquid separator according to an embodiment of the present invention.

Hereinafter, with reference to the attached drawings, preferred embodiments will be described in detail so that those skilled in the art can easily practice the present invention. However, when describing preferred embodiments of the present invention in detail, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. In addition, the same or similar symbols are used throughout the drawings for parts that perform similar functions and actions.

In addition, throughout the specification, when a part is said to be 'connected' to another part, this does not only mean 'directly connected', but also 'indirectly connected' with another element in between. Includes. Additionally, ‘including’ a certain component does not mean excluding other components, but rather including other components, unless specifically stated to the contrary.

Figure 1 is a diagram illustrating a refrigerant system of a gas-liquid separator according to an embodiment of the present invention, and Figure 2 is an enlarged view of portion A of Figure 1.

1 and 2, the air conditioner 10 according to an embodiment of the present invention includes an outdoor heat exchanger 131, an indoor heat exchanger 132, a compressor 140, and a gas-liquid separator 160. Includes.

The outdoor heat exchanger 131 and the indoor heat exchanger 132 function as a condenser that condenses the refrigerant compressed in the compressor 140 by exchanging heat with external air or an evaporator function that evaporates the condensed refrigerant by exchanging heat with external air. It can be done. A temperature sensor (not shown) that measures temperature may be provided on one side of the outdoor heat exchanger 131 and the indoor heat exchanger 132. A blowing fan may be further provided on one side of the outdoor heat exchanger 131 and the indoor heat exchanger 132 to help exchange heat with outside air.

The compressor 140 can suck in evaporated gaseous refrigerant from a heat exchanger that functions as an evaporator, compress it, and discharge the refrigerant to a heat exchanger that performs a condenser function. A temperature sensor that measures the temperature of the discharged refrigerant may be installed on one side of the compressor 140.

The gas-liquid separator 160 includes the gas-liquid separator main body having a vertical height, and is connected to the outdoor heat exchanger 131 and the indoor heat exchanger 132 to form the outdoor heat exchanger 131 and the indoor heat exchanger 132. The refrigerant condensed in (132) can be separated into gaseous refrigerant or liquid refrigerant. For example, the gas-liquid separator 160 may include a receiver that stores refrigerant.

The air conditioner 10 may include a first connection pipe 111 and a second connection pipe 112 connected to the gas-liquid separator 160.

The first connection pipe 111 may be connected to the outdoor heat exchanger 131. The first connection pipe 111 may be provided with a first valve 151 that regulates the flow of refrigerant. For example, the first valve 151 may include an electronic expansion valve. Additionally, the refrigerant may be depressurized by the first valve 151.

The second connection pipe 112 may be connected to the indoor heat exchanger 132. The second connection pipe 112 may be provided with a second valve 152 that regulates the flow of refrigerant.

For example, the second valve 152 may include an electronic expansion valve. Additionally, the refrigerant may be reduced in pressure by the second valve.

It may include a first branch pipe 121 and a first liquid pipe 111a branched from the first connection pipe 111 and connected to the gas-liquid separator 160.

The first branch pipe 121 may be spaced a certain distance from the upper surface of the gas-liquid separator 160 and protrude toward the inside.

The first branch pipe 121 may include a bent portion 121a bent inside the gas-liquid separator 160 toward the inner peripheral surface of the gas-liquid separator.

For example, the bent portion 121a may be bent downward by an appropriate angle α based on a line parallel to the upper side of the gas-liquid separator 160. The appropriate angle (α) may be a value between 30 and 90 degrees. Below the static angle (α), the potential energy of the refrigerant is large, so that when the refrigerant falls on the refrigerant remaining inside the gas-liquid separator 160, the gaseous refrigerant may flow into the lower side of the remaining refrigerant, thereby preventing separation of the refrigerant. It's not easy.

The bent portions 121a and 122a allow the abnormal refrigerant to flow along the inner wall of the gas-liquid separator 160, and the gaseous refrigerant and the liquid refrigerant can be easily separated while flowing along the wall.

The first branch pipe 121 may be provided with a first check valve 123 that regulates the refrigerant flowing into the first branch pipe 121. For example, the first check valve 123 may be opened during cooling operation and may be closed during heating operation.

The first liquid pipe 111a can suck the liquid refrigerant from the gas-liquid separator 160.

For example, the end of the first liquid pipe 111a may be located adjacent to the bottom of the gas-liquid separator 160.

The first liquid pipe 111a may be provided with a third check valve 125 that regulates the flow of refrigerant between the first branch 117 and the gas-liquid separator 160.

For example, the third check valve 125 may be closed during cooling operation and may be opened during heating operation.

In addition, it may include a second branch pipe 122 and a second liquid pipe 112a that branch from the second connection pipe 112 and flow into the gas-liquid separator 160.

The second branch pipe 122 may be spaced at a certain distance from the upper surface of the gas-liquid separator 160 and protrude toward the inside.

The second branch pipe 122 may include a bent portion 122a bent inside the gas-liquid separator 160 toward the inner peripheral surface of the gas-liquid separator.

For example, the bent portion 122a may be bent at an appropriate angle a toward the upper side of the gas-liquid separator 160.

The second branch pipe 122 may be provided with a second check valve 124 that regulates the refrigerant flowing into the second branch pipe 122. For example, the second check valve 124 may be closed during cooling operation and may be opened during heating operation.

The second liquid pipe 112a can suck the liquid refrigerant from the gas-liquid separator 160. For example, the end of the second liquid pipe 112a may be located adjacent to the bottom of the gas-liquid separator 160.

The second liquid pipe 112a may be provided with a fourth check valve 126 that regulates the flow of refrigerant between the second branch 118 and the gas-liquid separator 160. For example, the fourth check valve 126 may be opened during cooling operation and may be closed during heating operation.

The outdoor heat exchanger 131 may function as a condenser during cooling operation of the air conditioner 10. For example, the refrigerant condensed in the outdoor heat exchanger 131 may flow into the gas-liquid separator 160 along the first connection pipe 111 and the first branch pipe 121.

Additionally, the outdoor heat exchanger 131 may function as an evaporator during heating operation of the air conditioner 10. For example, the liquid refrigerant flowing into the outdoor heat exchanger 131 from the gas-liquid separator 160 may be decompressed in the first valve 151 and then evaporated in the outdoor heat exchanger.

The indoor heat exchanger 132 may function as an evaporator during cooling operation of the air conditioner 10. For example, the liquid refrigerant flowing into the indoor heat exchanger 132 from the gas-liquid separator 160 may be evaporated in the indoor heat exchanger 132 after being depressurized in the second valve 152. Additionally, the indoor heat exchanger 132 may function as a condenser during heating operation of the air conditioner 10. For example, the refrigerant condensed in the indoor heat exchanger 132 may flow into the gas-liquid separator 160 along the second connection pipe 112 and the second branch pipe 118.

The air conditioner 10 includes a third connection pipe 113 connecting the outdoor heat exchanger 131 and the flow switching valve 150, and the indoor heat exchanger 132 and the flow switching valve 150. It may include a fourth connection pipe 114 connecting the .

The third connection pipe 113 may communicate with the fifth connection pipe 115 or the sixth connection pipe 116 by the flow switching valve 150.

The fourth connection pipe 114 may communicate with the fifth connection pipe 115 and the sixth connection pipe 116 by the flow switching valve 150.

The fifth connection pipe 115 and the sixth connection pipe 116 may be connected to the compressor 140.

Refrigerant may be sucked into the compressor from the fifth connection pipe 115. The fifth connection pipe 115 may be called “suction pipe.”

Refrigerant may be discharged from the compressor 140 to the sixth connection pipe 116. The sixth connection pipe 116 may be called a “discharge pipe.”

A temperature sensor (not shown) that measures the discharge temperature of the compressor 140 may be provided on one side of the sixth connection pipe 116.

The air conditioner 10 may include an injection pipe 119 connected to the compressor 140 and the gas-liquid separator 160.

The injection pipe 119 may be connected to the upper surface of the gas-liquid separator 160.

For example, the end of the injection pipe 119 may be positioned in contact with the upper surface of the gas-liquid separator 160, or may be formed to protrude inward at a predetermined distance from the upper surface of the gas-liquid separator 160.

The injection pipe 119 can flow only the gaseous refrigerant inside the gas-liquid separator 160 to the compressor 140.

The injection pipe 119 may flow into the medium pressure end of the compressor 140.

A third valve 153 that regulates the flow of gaseous refrigerant may be provided on one side of the injection pipe 119. For example, the third valve may include a solenoid valve that can be adjusted on and off. For example, the third valve 153 may include an electronic control valve, an on-off valve, a check valve, etc.

A temperature sensor may be further provided on one side of the injection pipe 119.

Figure 3 is a diagram showing the refrigerant flow of the air conditioner according to an embodiment of the present invention during cooling operation, and Figure 4 is a diagram showing a control method of the air conditioner according to an embodiment of the present invention during cooling operation.

Referring to FIG. 3, during cooling operation of the air conditioner 10, the refrigerant discharged from the compressor 140 to the sixth connection pipe 116 may flow into the flow switching valve 150.

The flow switching valve 150 is connected to the third connection pipe 113, and the refrigerant may flow into the outdoor heat exchanger 131 along the third connection pipe 113.

The outdoor heat exchanger 131 functions as a condenser, and the refrigerant is condensed in the outdoor heat exchanger 131.

Condensed refrigerant may be in a state of a refrigerant that is a mixture of liquid and gas states. Condensed refrigerant may flow along the first connection pipe 111. The condensed refrigerant may be reduced in pressure by the first valve 151. For example, the first valve 151 can control the degree of subcooling of the refrigerant in the outdoor heat exchanger 131 during cooling operation.

The reduced pressure refrigerant may branch from the first branch 117 of the first connection pipe 111 and flow into the first branch pipe 121. At this time, the first check valve 123 may be in an open state, and the third check valve 125 may be in a closed state. Accordingly, it is possible to prevent the reduced pressure refrigerant from flowing into the first liquid pipe (111a).

The refrigerant flowing into the first branch pipe 121 may flow into the gas-liquid separator 160 along the first branch pipe 121. For example, reduced pressure refrigerant may flow along the inner wall of the gas-liquid separator 160 at the bent portion 121a of the first branch pipe 121.

The abnormal refrigerant decompressed in the gas-liquid separator 160 may be separated into gaseous refrigerant and liquid refrigerant.

The gaseous refrigerant from the gas-liquid separator 160 may flow into the medium pressure end of the compressor 140 along the injection pipe 119. At this time, the third valve may be in an open state.

The liquid refrigerant in the gas-liquid separator 160 may be sucked into the second liquid pipe 112a and flow into the indoor heat exchanger 132 along the second connection pipe 112. The liquid refrigerant may be reduced in pressure in the second valve 152. The reduced pressure refrigerant may be evaporated in the indoor heat exchanger 132.

The refrigerant heat-exchanged in the indoor heat exchanger 132 flows into the flow conversion valve 150 along the fourth connection pipe 114, and the fifth connection pipe 115 communicates with the flow conversion valve 150. It may flow into the compressor 140 along .

During cooling operation, the cycle may be performed repeatedly.

Referring to FIG. 4, the air conditioner 10 is turned on and cooling operation can be input (S11, S12).

When the cooling operation starts, the compressor 140 and the fan are operated (S13). At the start of the cooling operation, both the first valve 151 and the second valve 152 may be in an open state.

The gas-liquid separator 160 may be subjected to medium pressure control to prevent the liquid refrigerant of the gas-liquid separator 160 from flowing into the injection pipe 119 (S14).

In order to control the medium pressure of the gas-liquid separator 160, a step of determining whether the rotation speed (Hz) of the compressor 140 is more than the set rotation speed so that the cooling operation of the air conditioner 10 can be performed for a certain period of time is performed. It can be performed (S15).

If the compressor rotation speed (Hz) is less than the set rotation speed, the air conditioner 10 may not be sufficiently operated in the cooling operation, and the inside of the gas-liquid separator 160 may be full of refrigerant at the beginning of operation, so the injection pipe 119 ) A problem may occur where the liquid refrigerant flows to the compressor 140.

Therefore, if the compressor rotation speed (Hz) is less than the set rotation speed, the compressor is operated until the rotation speed (Hz) of the compressor becomes more than the set rotation speed, and the rotation speed of the compressor 140 can be determined again.

If the compressor rotation speed (Hz) is more than the set rotation speed, that is, when the intermediate pressure of the gas-liquid separator 160 is controlled, the opening degree of the first valve 151 can be controlled to control the degree of subcooling (S16) ). For example, the degree of subcooling can be determined by the difference between the saturated condensation temperature of the condenser and the current condensation temperature.

In order to control the degree of subcooling, a step of determining whether the current degree of subcooling is less than the target degree of subcooling may be performed (S17).

If the degree of subcooling is less than the target degree of subcooling, the opening degree of the first valve 151 may be reduced (S18). For example, the speed at which the opening degree of the first valve 151 is reduced can be changed.

When the opening degree of the first valve 151 decreases, the refrigerant flow rate in the outdoor heat exchanger 131 decreases, and refrigerant may accumulate in the outdoor heat exchanger 131. The refrigerant may be further condensed in the outdoor heat exchanger 131, thereby increasing the degree of subcooling.

When the degree of subcooling is greater than the target degree of subcooling, the opening degree of the first valve 151 can be increased (S19). For example, the speed at which the opening degree of the first valve 151 is increased can be changed.

When the opening degree of the first valve 151 increases, the refrigerant flow rate in the outdoor heat exchanger 131 may increase and the degree of subcooling of the refrigerant condensed in the outdoor heat exchanger 131 may decrease.

Thereafter, in order to control the flow rate on the evaporator (indoor heat exchanger) side, a step of comparing the current discharge temperature of the refrigerant discharged from the outlet side of the compressor 140 and the target discharge temperature can be performed (S20).

If the current discharge temperature is less than the target discharge temperature, the opening degree of the second valve 152 may be reduced to reduce the flow rate of the liquid refrigerant flowing into the indoor heat exchanger 132 (S21). For example, the speed at which the opening degree of the second valve 152 is reduced can be changed.

When the opening degree of the second valve 152 is reduced, the flow rate of the refrigerant flowing into the indoor heat exchanger 132 is reduced, and the refrigerant can be sufficiently evaporated in the indoor heat exchanger 132. That is, because the refrigerant is overheated and flows into the compressor 140, the temperature of the refrigerant discharged from the outlet side of the compressor 140 may increase. In addition, when sufficient evaporation of the refrigerant occurs in the indoor heat exchanger 132, the refrigerant flowing into the compressor 140 may contain more gaseous refrigerant, thereby increasing the reliability and efficiency of the compressor 140. .

If the current discharge temperature is higher than the target discharge temperature, it is determined that the refrigerant is excessively overheated in the indoor heat exchanger 132, and the opening degree of the second valve 152 can be increased (S22). For example, the speed at which the opening degree of the second valve 152 is increased can be changed.

When the opening degree of the second valve 152 is increased, the flow rate of refrigerant flowing into the indoor heat exchanger 132 may increase, and the flow rate of liquid refrigerant flowing into the indoor heat exchanger 132 may increase. there is.

In the indoor heat exchanger 132, the refrigerant can flow into the compressor 140 without being overheated. Accordingly, the discharge temperature at the outlet side of the compressor 140 can be set to the set discharge temperature.

After adjusting the opening degree of the second valve 152 (S21, S22), a step of determining whether the current operation time is more than the set operation time may be performed (S23).

The set operation time is the time when the air conditioner 10 operates for the set operation time and reaches a level at which the liquid refrigerant does not flow into the injection pipe 119 inside the gas-liquid separator 160. It can mean.

If the current operation time is greater than or equal to the set operation time, the third valve 153 may be opened (S24). For example, the speed at which the opening degree of the third valve 153 expands can be changed.

When the opening degree of the third valve 153 is expanded, the gaseous refrigerant inside the gas-liquid separator 160 may flow into the injection pipe 119. The gaseous refrigerant flowing through the injection pipe 119 may flow into the medium pressure end of the compressor 140.

After the third valve 153 is opened (S24), the cycle is stabilized and a step of comparing the current degree of subcooling and the target degree of subcooling is performed (S25) to determine whether the state of the first valve 151 remains stable. can do.

If the current degree of subcooling is less than the target subcooling degree, it is determined that the first valve 151 is not stabilized, and the first valve 151 is returned to the step (S17) of determining whether the current degree of subcooling is less than the target subcooling degree. The opening degree of the valve 151 can be reduced (S18).

On the other hand, if the current degree of subcooling is greater than the target degree of subcooling, it is determined that the first valve 151 is stabilized and the opening degree of the first valve 151 is maintained (S26).

When the first valve 151 is stabilized and maintains the opening degree, a step of determining whether the target discharge temperature matches the set discharge temperature value may be performed to determine whether the second valve 152 is stabilized. (S27).

If the target discharge temperature does not match the set discharge temperature, the process may be performed again after returning to the step (S25) of comparing the current subcooling degree and the target subcooling degree.

When the target discharge temperature matches the set discharge temperature, the second valve 152 is determined to be stabilized and the opening degree of the second valve 152 can be maintained (S28).

After the step (S28) in which the second valve 152 is maintained, a step (S29) of determining a change in the current discharge temperature at the outlet side of the compressor 140 for a certain period of time may be performed.

The change in the current discharge temperature over the predetermined time is determined after the step in which the first valve 151 and the second valve 152 maintain their opening degrees. An example of the change occurring is within the compressor 140. This can be understood as a case where liquid refrigerant from the gas-liquid separator 160 flows in. When the liquid refrigerant flows into the compressor 140, the current discharge temperature may decrease.

If the current discharge temperature change amount per predetermined time is greater than or equal to a specific change amount value, the third valve 153 may be closed (S30). For example, the specific change value may be a negative number. Additionally, the speed at which the opening degree of the third valve 153 decreases can be changed.

After the third valve 153 is closed, a step of determining whether operation of the air conditioner 10 is terminated may be performed (S31).

When the end of operation of the air conditioner 10 is input, the operation of the air conditioner 10 may be terminated.

If the end of operation of the air conditioner 10 is not input, the process may proceed by returning to step S23 of determining whether the current operation time is more than the set operation time.

Figure 5 is a diagram showing the refrigerant flow of the air conditioner according to an embodiment of the present invention during heating operation, and Figure 6 is a diagram showing a control method of the air conditioner according to an embodiment of the present invention during heating operation.

Referring to FIG. 5, during the heating operation of the air conditioner 10, the refrigerant discharged from the compressor 140 to the sixth connection pipe 116 may flow into the flow switching valve 150.

The flow switching valve 150 is connected to the fourth connection pipe 113, and the refrigerant may flow into the indoor heat exchanger 132 along the fourth connection pipe 113.

The indoor heat exchanger 132 functions as a condenser, and the refrigerant is condensed in the indoor heat exchanger 132. The condensed refrigerant may be in a state of refrigerant where liquid and gas phases are mixed.

The condensed refrigerant may flow along the second connection pipe 112 and be reduced in pressure as it passes through the second valve 152.

The reduced pressure refrigerant may be branched from the second branch 118 of the second connection pipe 112 and flow into the second branch pipe 122. At this time, the second check valve 124 may be in an open state, and the fourth check valve 126 may be in a closed state.

The refrigerant flowing into the second branch pipe 122 may flow into the gas-liquid separator 160 along the second branch pipe 122. For example, reduced pressure refrigerant may flow along the inner wall of the gas-liquid separator 160 at the bent portion 122a of the second branch pipe 122.

The gaseous refrigerant from the gas-liquid separator 160 may flow into the medium pressure end of the compressor 140 along the injection pipe 119. At this time, the third valve 153 may be in an open state.

The liquid refrigerant of the gas-liquid separator 160 may be sucked into the first liquid pipe 111a and flow into the outdoor heat exchanger 131 along the first connection pipe 111. The refrigerant flowing along the first connection pipe 111 may be depressurized in the first valve 151.

The reduced pressure refrigerant may be evaporated in the outdoor heat exchanger 131. The refrigerant heat-exchanged in the outdoor heat exchanger 131 flows into the flow conversion valve 150 along the third connection pipe 113, and the fifth connection pipe 115 communicates with the flow conversion valve 150. It may flow into the compressor 140 along .

During heating operation, the cycle may be performed repeatedly.

Referring to FIG. 6, the air conditioner 10 is turned on and heating operation can be input (S51, S52).

When the heating operation starts, the compressor 140 and the fan are operated (S53). At the start of the heating operation, both the first valve 151 and the second valve 152 may be in an open state.

The gas-liquid separator 160 may be subjected to medium pressure control to prevent the liquid refrigerant of the gas-liquid separator 160 from flowing into the injection pipe 119 (S54).

A step of determining whether the rotation speed (Hz) of the compressor 140 is greater than or equal to a set rotation speed may be performed so that the heating operation of the air conditioner 10 can be performed for a certain period of time (S55).

If the compressor rotation speed (Hz) is less than the set rotation speed, the compressor is operated until the rotation speed (Hz) of the compressor becomes more than the set rotation speed, and the rotation speed of the compressor 140 can be determined again.

When the compressor rotation speed (Hz) is less than the set rotation speed, the operating time for cooling operation of the air conditioner 10 may be short, and the inside of the gas-liquid separator 160 may be full of refrigerant at the beginning of operation, so the injection A problem may occur where liquid refrigerant flows toward the pipe 119 and flows into the compressor 140.

On the other hand, when the compressor rotation speed (Hz) is more than the set rotation speed, that is, when the intermediate pressure of the gas-liquid separator 160 is controlled, the opening degree of the second valve 152 can be controlled to control the degree of subcooling. (S56).

In order to control the degree of subcooling, a step of determining whether the current degree of subcooling is less than the target degree of subcooling may be performed (S57).

If the degree of subcooling is less than the target degree of subcooling, the opening degree of the second valve 152 may be reduced (S58). For example, the speed at which the opening degree of the second valve 152 is reduced can be changed.

When the opening degree of the second valve 152 decreases, the flow rate of the refrigerant flowing along the second connection pipe 112 decreases, and the refrigerant may accumulate in the indoor heat exchanger 132.

The refrigerant can be easily condensed in the indoor heat exchanger 132, thereby increasing the degree of subcooling.

When the degree of subcooling is greater than the target degree of subcooling, the opening degree of the second valve 152 can be increased (S59). For example, the speed at which the opening degree of the second valve 152 is increased can be changed.

When the opening degree of the second valve 152 increases, the flow rate of the refrigerant flowing along the second connection pipe 112 increases and the degree of subcooling of the refrigerant condensed in the indoor heat exchanger 132 may decrease. .

Thereafter, in order to control the flow rate on the evaporator (outdoor heat exchanger) side, a step of comparing the current discharge temperature of the refrigerant discharged from the outlet side of the compressor 140 and the target discharge temperature may be performed (S60).

If the current discharge temperature is less than the target discharge temperature, the opening degree of the first valve 151 may be reduced to reduce the flow rate of the liquid refrigerant flowing into the outdoor heat exchanger 131 (S61). For example, the speed at which the opening degree of the first valve 151 is reduced can be changed.

When the opening degree of the first valve 151 is reduced, the flow rate of the refrigerant flowing through the first connection pipe 111 is reduced, and the reduced pressure refrigerant can be sufficiently evaporated in the outdoor heat exchanger 131. Accordingly, the temperature of the refrigerant discharged from the outlet side of the compressor 140 may increase. When sufficient evaporation of the refrigerant occurs in the outdoor heat exchanger 131, the refrigerant flowing into the compressor 140 may contain more gaseous refrigerant, thereby increasing the reliability and efficiency of the compressor 140.

If the current discharge temperature is higher than the target discharge temperature, it is determined that the refrigerant flowing into the compressor 140 is overheated, and the opening degree of the first valve 151 can be increased (S62). For example, the speed at which the opening degree of the first valve 151 is increased can be changed. As the opening degree of the first valve 151 increases, the flow rate of refrigerant flowing into the outdoor heat exchanger 131 may increase. Therefore, the refrigerant from the outdoor heat exchanger 131 can flow into the compressor 140 without being overheated.

After adjusting the opening degree of the first valve 151 (S61, S62), a step of determining whether the current operation time is more than the set operation time may be performed (S63).

The set operation time is the time when the air conditioner 10 operates for the set operation time and reaches a level inside the gas-liquid separator 160 at which liquid refrigerant does not flow into the injection pipe 119. It can mean.

If the current operation time is greater than or equal to the set operation time, the third valve 153 may be opened (S64). For example, the speed at which the opening degree of the third valve 153 expands can be changed.

When the opening degree of the third valve 153 is expanded, the gaseous refrigerant inside the gas-liquid separator 160 may flow into the injection pipe 119. The gaseous refrigerant flowing through the injection pipe 119 may flow into the medium pressure end of the compressor 140.

After the third valve 153 is opened (S64), the cycle is stabilized and a step of comparing the current degree of subcooling and the target degree of subcooling is performed (S65) to determine whether the state of the second valve 152 remains stable. can do.

If the current degree of subcooling is less than the target subcooling degree, it is determined that the second valve 152 is not stabilized, and the second valve 152 returns to the step of determining whether the current degree of subcooling is less than the target subcooling (S67). The opening degree of the valve 152 can be reduced (S58).

On the other hand, if the current degree of subcooling is greater than or equal to the target degree of subcooling, it is determined that the second valve 152 is stabilized and the opening degree of the second valve 152 is maintained (S66).

When the second valve 152 is stabilized and maintains the opening degree, a step of determining whether the target discharge temperature matches the set discharge temperature value may be performed to determine whether the first valve 151 is stabilized. (S67).

If the target discharge temperature does not match the set discharge temperature, the process may proceed after returning to the step (S65) of comparing the current degree of subcooling and the target degree of subcooling.

When the target discharge temperature matches the set discharge temperature, the first valve 151 is determined to be stabilized and the opening degree of the first valve 151 can be maintained (S68).

After the step (S68) in which the first valve 151 is maintained, a step (S69) of determining a change in the current discharge temperature at the outlet side of the compressor 140 for a certain period of time may be performed.

The change in the current discharge temperature over the predetermined time is determined after the step in which the first valve 151 and the second valve 152 maintain their opening degrees. An example of the change occurring is within the compressor 140. This can be understood as a case where liquid refrigerant from the gas-liquid separator 160 flows in. When the liquid refrigerant flows into the compressor 140, the current discharge temperature may decrease.

If the current discharge temperature change amount per predetermined time is greater than or equal to a specific change amount value, the third valve 153 may be closed (S70). For example, the specific change value may be a negative number. Additionally, the speed at which the opening degree of the third valve 153 is reduced can be changed.

After the third valve 153 is closed, a step of determining whether operation of the air conditioner 10 is terminated may be performed (S71).

When the end of operation of the air conditioner 10 is input, the operation of the air conditioner 10 may be terminated.

If the end of operation of the air conditioner 10 is not input, the process may proceed by returning to the step S63 of determining whether the current operation time is more than the set operation time.

Figure 7 is a diagram comparing the P-H diagram when the opening degree of the valve of the air conditioner according to the present invention is changed.

Referring to FIG. 7, in the following, one embodiment of FIG. 7(a) will be referred to as Case1, and another embodiment of FIG. 7(b) will be described as Case2.

First, with reference to FIG. 7(a), the cycle according to the embodiment of the present invention will be compared with the existing cycle.

Point A can be understood as the position of the suction side of the compressor 140. The A-C section is a section where the refrigerant is compressed in the compressor 140. Enthalpy and pressure may increase in the A-C section. Point B between the sections A-C can be understood as a point where enthalpy is reduced by the gaseous refrigerant flowing from the injection pipe 119 to the compressor 140. Unlike the cycle of a conventional air conditioner, in the present invention, gaseous refrigerant can flow into the medium pressure end of the compressor 140 through the injection pipe 119, so enthalpy can be reduced. However, since only pure gaseous refrigerant that has not been evaporated flows into the compressor 140, the reliability of the compressor can be improved.

The C-D section is a section in which the refrigerant discharged from the compressor 140 is condensed in the outdoor heat exchanger 131 (condenser). Point D is a point where the first valve 151 is located, and the refrigerant can be decompressed and expanded by the first valve 151 in the D-E section.

The E-F section can be understood as the state of the refrigerant in the gas-liquid separator 160, and the point E can be understood as the point where the third valve 153 is located. The refrigerant that bypasses from point E to point B can only be bypassed by refrigerant in a gaseous state. In the E-F section, enthalpy may decrease because only the liquid refrigerant of the gas-liquid separator 160 flows to the second connection pipe 112.

Point F is a point where the second valve 152 is located, and the refrigerant can be decompressed and expanded by the second valve 152 in the F-G section. The refrigerant may expand and exist in an abnormal refrigerant state.

Due to the D-G section, the evaporator inlet enthalpy of the cycle according to the embodiment of the present invention may be lower than the evaporator inlet enthalpy of the existing cycle.

The G-A section is a section in which the abnormal refrigerant evaporates in the indoor heat exchanger 132 (evaporator). The evaporated refrigerant may flow into the suction side of the compressor 140 at point A.

Next, Case 1 in Figure 7(a) and Case 2 in Figure 7(b) will be compared and explained based on cooling operation.

In Case 1, the opening degrees of the first valve 151 and the second valve 152 are set to be greater than the opening degrees of the first valve 151 and the second valve 152 in Case 2.

First, comparing the outdoor heat exchanger 131 (condenser) side, in Case 2, the opening degree of the first valve 151 is set smaller than the opening degree of the first valve 151 in Case 2, so that the outdoor heat exchanger 131 (condenser) side is compared. The flow rate of the refrigerant passing through the group 131 (condenser) may be slower than in Case 2. As described above, if the flow rate of the refrigerant is slow, the degree of subcooling of the refrigerant on the outdoor heat exchanger 131 may increase. Therefore, the length of the section C'-D' in Case 2 may be longer than the section C-D in Case 1.

Case 2 may be more subcooled than Case 1, so that the vapor phase refrigerant decompressed in the first valve device 151 may be less. In other words, it can be seen that point E is located further away from the saturated liquid line than point E'.

Next, when comparing the indoor heat exchanger 132 (evaporator) side, it can be seen that point A of Case 1 is located to the left of the saturated steam line, and point A' of Case 2 is located to the right of the saturated steam line and is in an overheated state. .

In Case 2, the opening degree of the second valve 152 is set to be smaller than the opening degree of the second valve 152 in Case 2, so that the flow rate of the refrigerant passing through the indoor heat exchanger 132 (evaporator) is higher than that in Case 2. It can be slow. As described above, the refrigerant in the indoor heat exchanger 132 is overheated and only the gaseous refrigerant can flow to the compressor 140. For example, in Case 1, the indoor heat exchanger 132 fails to overheat and abnormal refrigerant flows into the compressor 140, which may cause wet compression in the compressor 140.

Hereinafter, since the heating operation is opposite to the refrigerant flow of the cooling operation, it can be understood that the opening degrees of the first valve 151 and the second valve 152 are adjusted according to the refrigerant flow.

Figure 8 is a diagram showing several examples of a gas-liquid separator according to an embodiment of the present invention.

Referring to FIG. 8(a), in the first embodiment according to FIG. 8(a), the gas-liquid separator 160 includes the first liquid pipe 111a and the second liquid pipe on the upper surface of the gas-liquid separator 160. (112a) is connected, and the first branch pipe 121 and the second branch pipe 122 are connected to the upper surface of the gas-liquid separator 160.

The third check valve 125 provided in the first liquid pipe 111a may be positioned spaced upward from the upper surface of the gas-liquid separator 160.

The fourth check valve 126 provided in the second liquid pipe 112a may be positioned spaced upward from the upper surface of the gas-liquid separator 160.

Referring to FIG. 8(b), in the second embodiment according to FIG. 8(b), the gas-liquid separator 160 has the first liquid pipe 111a and the second liquid pipe on the outer peripheral surface of the gas-liquid separator 160. (112a) is connected, and the first branch pipe 121 and the second branch pipe 122 are connected to the upper surface of the gas-liquid separator 160.

The third check valve 125 provided in the first liquid pipe 111a may be positioned spaced apart from the outer peripheral surface of the gas-liquid separator 160 in the outer direction of the gas-liquid separator 160.

The fourth check valve 126 provided in the second liquid pipe 112a may be located spaced apart from the outer peripheral surface of the gas-liquid separator 160 in the outer direction of the gas-liquid separator 160.

Referring to FIG. 8(c), in the third embodiment according to FIG. 8(c), the gas-liquid separator 160 has the first liquid pipe 111a and the second liquid pipe on the lower surface of the gas-liquid separator 160. (112a) is connected, and the first branch pipe 121 and the second branch pipe 122 are connected to the upper surface of the gas-liquid separator 160.

A bracket 400 for separating the gas-liquid separator 160 from the lower end of the inner space of the outdoor unit in order to connect the first liquid pipe 111a and the second liquid pipe 112a to the lower surface of the gas-liquid separator 160. More can be provided.

The third check valve 125 provided in the first liquid pipe 111a may be located higher than the lower surface of the gas-liquid separator 160.

The fourth check valve 126 provided in the second liquid pipe 112a may be located higher than the lower surface of the gas-liquid separator 160.

Referring to FIG. 8(d), in the fourth embodiment according to FIG. 8(d), the gas-liquid separator 160 has the first liquid pipe 111a and the second liquid pipe on the lower surface of the gas-liquid separator 160. (112a) is connected, and the first branch pipe 121 and the second branch pipe 122 are connected to the upper surface of the gas-liquid separator 160.

A bracket 400 for separating the gas-liquid separator 160 from the lower end of the inner space of the outdoor unit in order to connect the first liquid pipe 111a and the second liquid pipe 112a to the lower surface of the gas-liquid separator 160. More can be provided.

The third check valve 125 provided in the first liquid pipe 111a may be located lower than the lower surface of the gas-liquid separator 160.

The fourth check valve 126 provided in the second liquid pipe 112a may be located lower than the lower surface of the gas-liquid separator 160.

111: first connection pipe 112: second connection pipe
117: first branch 118: second branch
111a: First liquid pipe 112a: Second liquid pipe
121: First Branch Hall 122: Second Branch Hall
151: first valve device 152: second valve device

Claims (16)

A compressor that compresses refrigerant;
outdoor heat exchanger; and indoor heat exchanger;
a gas-liquid separator that separates abnormal refrigerant condensed in the outdoor heat exchanger or the indoor heat exchanger into liquid refrigerant and gaseous refrigerant; and
A first connection pipe connecting the outdoor heat exchanger and the gas-liquid separator and on which a first valve is installed; and
It connects the indoor heat exchanger and the gas-liquid separator, and includes a second connection pipe on which a second valve is installed,
At least one of the first connection pipe and the second connection pipe,
A branch section that branches out the refrigerant into the gas-liquid separator;
a liquid pipe branching from the branch and sucking the liquid refrigerant inside the gas-liquid separator; and
An air conditioner including a branch pipe that discharges refrigerant into the gas-liquid separator. According to claim 1,
The branch part includes a first branch part branched from the first connection pipe and a second branch part branched from the second connection pipe,
The liquid pipe includes a first liquid pipe branched from the first branch and a second liquid pipe branched from the second branch,
The branch pipe is an air conditioner including a first branch pipe branched from the first branch portion and a second branch pipe branched from the second branch portion. According to claim 2,
The first and second valves are an air conditioner including an expansion valve whose opening can be adjusted to depressurize the condensed refrigerant. In clause 3,
A first check valve provided in the first branch pipe and controlling the flow of refrigerant; and
An air conditioner further comprising a second check valve provided in the second branch pipe and controlling the flow of refrigerant. According to claim 4,
A third check valve provided in the first liquid pipe and controlling the flow of refrigerant;
An air conditioner further comprising a fourth check valve provided in the second liquid pipe and controlling the flow of refrigerant. According to claim 2,
It includes an injection pipe for introducing the gaseous refrigerant separated in the gas-liquid separator into the compressor,
An air conditioner further comprising a third valve provided in the injection pipe and controlling the flow of gaseous refrigerant. According to claim 6,
An air conditioner wherein the injection pipe is connected to the medium pressure end of the compressor. According to clause 2,
The gas-liquid separator includes a gas-liquid separator body having a vertical height,
So that the condensed refrigerant can flow into the interior of the gas-liquid separator through the top of the gas-liquid separator main body,
The first branch pipe, the second branch pipe, the first liquid pipe, and the second liquid pipe are connected to the upper surface of the gas-liquid separator. According to clause 8,
The first branch pipe and the second branch pipe include a bent portion that is bent to discharge the refrigerant toward the inner wall of the gas-liquid separator. According to clause 9,
An air conditioner in which the bent portion is bent between 30 and 90 degrees toward the inner peripheral surface of the gas-liquid separator. According to claim 1,
A flow conversion valve that switches the flow of refrigerant;
A third connection pipe connecting the outdoor heat exchanger and the flow switching valve;
A fourth connection pipe connecting the indoor heat exchanger and the flow switching valve;
An air conditioner further comprising a fifth connection pipe and a sixth connection pipe respectively connecting the flow conversion valve and the compressor. Entering an operation mode and operating the compressor;
determining whether the rotation speed of the compressor is greater than or equal to a set rotation speed;
If it is determined that the rotation speed of the compressor is higher than the set rotation speed,
Comparing the subcooling degree, which is the difference between the saturated condensation temperature of the condenser and the current condensation temperature, with the target subcooling degree,
A control method of an air conditioner comprising comparing the current degree of subcooling with the target degree of subcooling and adjusting the opening degree of a valve adjacent to the condenser. According to claim 12,
After the step of adjusting the opening degree of the valve adjacent to the condenser is performed,
Further comprising comparing the current discharge temperature at the compressor outlet side and the target discharge temperature,
A control method of an air conditioner including the step of adjusting the opening degree of a valve adjacent to the evaporator according to the comparison result. According to claim 13,
While performing the step of adjusting the valve adjacent to the evaporator according to the comparison between the current discharge temperature of the compressor and the target discharge temperature,
A method of controlling an air conditioner further comprising comparing whether the current operating time of the compressor is the set operating time. According to claim 14,
A control method of an air conditioner including the step of expanding the opening degree of the third valve when the current operation time is greater than or equal to the set operation time. According to claim 15,
After the step of expanding the opening degree of the third valve,
A control method of an air conditioner comprising closing the third valve when the amount of change in the current discharge temperature for a certain period of time is greater than a specific amount of change.

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