KR20170045526A

KR20170045526A - Indoor unit of air conditioner

Info

Publication number: KR20170045526A
Application number: KR1020150145178A
Authority: KR
Inventors: 김승엽; 정재은; 이동수; 이장우
Original assignee: 엘지전자 주식회사
Priority date: 2015-10-19
Filing date: 2015-10-19
Publication date: 2017-04-27
Also published as: KR101797297B1

Abstract

The present invention relates to an air conditioner for increasing the supercooling degree by using an indoor fan of a non-operating (indoor) indoor unit to rapidly perform the liquid level decompression operation and to reduce the refrigerant expansion noise generated during the operation of removing the liquid level of the refrigerant Control method.
To this end, the present invention determines the supercooling degree by judging the inlet side temperature (T1) and the discharge temperature of the cooling system to be heated, drives the indoor fan toward the indoor heat exchanger to raise the supercooling degree, (OFF) indoor unit is opened at a predetermined opening degree to eliminate liquid accumulation, and the opening degree of the expansion device is closed.

Description

[0001] The present invention relates to an indoor unit of an air conditioner,

The present embodiment relates to an indoor unit of an air conditioner.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly, to a control method of an air conditioner which reduces noises generated when a liquid level of a refrigerant is relieved during a heating operation and quickly disappears.

The air conditioner is divided into an air conditioner in which one indoor unit is connected to one outdoor unit and an air conditioner in which a plurality of indoor units are connected to one outdoor unit.

The air conditioner includes a switching type air conditioner which operates all the indoor units only in the cooling only mode or the heating only mode according to the structure and operation mode of the cooling system and a switching type air conditioner in which some indoor units are operated in the cooling mode, And the air conditioner is operated by the air conditioner.

In the simultaneous-type air conditioner, only a part of the indoor units performs the heating operation because the refrigerant discharged from the compressor is supplied to only some of the indoor units. As the heating operation progresses, the refrigerant flows unnecessarily into the heat exchanger and the inlet pipe of the non-operated (indoor) indoor unit, resulting in a liquid accumulation phenomenon.

In order to prevent such a liquid accumulation phenomenon, the expansion device installed in the refrigerant pipe of the non-operation (indoor) indoor unit is opened every predetermined cycle to eliminate the liquid gassing of the refrigerant. Accordingly, the efficiency of the cooling system can be prevented from being lowered by recovering the circulation amount of the refrigerant by recovering the refrigerant flowing into the off-state indoor unit in a running cooling cycle.

However, the simultaneous-type air conditioner has the following problems.

First, since the liquid gum solving operation is performed uniformly at regular intervals, there is a problem that the liquid gum solving operation can not be performed at an appropriate timing. Therefore, the operation of removing the liquid droplets is carried out irrespective of the amount of liquid droplets, so that it is unnecessarily performed too frequently or even when the time has elapsed.

Second, since the liquid droplet elimination operation is performed uniformly irrespective of the state of the liquid droplets, there is a problem that irregular and large refrigerant expansion noise is generated. This noise is generated when the refrigerant is re-expanded when the two phase refrigerant and the high-pressure gas accumulated in the off-state indoor unit flow into the cooling system in which a part of the refrigerant is heated.

Thirdly, as the opening degree of the opening / closing valve is decreased, the refrigerant expansion noise is reduced, but the time required for solving the liquid accumulation is prolonged, so that it is difficult to reduce the noise and quickly solve the liquid accumulation.

Accordingly, there is a desperate need to be able to solve the problem of liquid accumulation quickly while minimizing noise.

Prior art information related to this is as follows.

Application number (filing date): 10-2005-0076080 (05. 07. 26)

Title of the Invention: Control method of air conditioner.

In order to solve the above problems, the present invention is to solve the above-mentioned problems, and to solve the above-mentioned problems, The present invention also provides a control method for a multi-type air conditioner.

The indoor unit of the air conditioner according to one aspect includes the steps of calculating an undercooling degree by measuring an inlet side temperature and an outlet side temperature of an indoor heat exchanger of a non-operation indoor unit in which heating operation is not performed; And driving the indoor fan according to the supercooling degree.

The method further includes increasing or decreasing the opening degree of the expansion window according to the supercooling degree.

Determining whether the non-operation indoor unit is in a liquid state; And reducing the opening of the expansion device if the liquid jam is relieved.

Also, an indoor unit of the air conditioner is provided in which a part of the indoor unit performs the heating operation, the other indoor unit is off, and the indoor fan of the indoor unit that is turned off is driven to supercool the refrigerant in the indoor heat exchanger.

Also, there is provided an indoor unit of an air conditioner that estimates a subcooling degree through a temperature sensor, drives an indoor fan according to the subcooling degree, and increases or decreases an opening degree of the valve.

According to the proposed embodiment, it is possible to rapidly increase the supercooling degree of the refrigerant in the interior of the indoor heat exchanger.

Further, the noise caused by the refrigerant passing through the expansion device can be reduced.

In addition, it is possible to quickly solve the phenomenon of liquid accumulation of the refrigerant, thereby preventing a reduction in efficiency of the system.

1 is a view of an air conditioner according to an embodiment of the present invention.
2 is a view of an indoor unit of an air conditioner according to an embodiment of the present invention.
3 is a block diagram of an air conditioner according to an embodiment of the present invention.
4 is a view of a control method of an air conditioner according to an embodiment of the present invention.
5 is a view of the operation of an indoor fan and an expansion device of an air conditioner according to an embodiment of the present invention.

Hereinafter, embodiments will be described in detail with reference to the drawings.

Hereinafter, an example of an air conditioner to which the control method according to the present invention is applied will be described with reference to FIG.

1 is a view of an air conditioner according to an embodiment of the present invention. 1, at least two indoor units 30a, 30b and 30c are connected to one outdoor unit 10 by a refrigerant pipe and a distributor 20 is connected to a refrigerant pipe between the outdoor unit and the indoor unit. Respectively.

The outdoor unit 10 includes at least one or all of the compressor 11, the outdoor heat exchanger 12, the outdoor indoor fan 13, and the accumulator 14.

At this time, in the distributor 20, the first refrigerant pipe 21 and the second refrigerant pipe 22 are branched by the number of the indoor units. The branch pipes 21a, 21b, 21c, 22a, 22b and 22c of the first and second refrigerant pipes 21 and 22 are connected to the respective indoor units.

Each of the indoor units 30a, 30b and 30c includes at least one or all of the indoor heat exchangers 31a, 31b and 31c, the indoor indoor fans 32a, 32b and 32c and the expansion units 33a, 33b and 33c . At this time, the branch pipes 21a, 21b, and 21c of the first refrigerant pipe 21 are provided with expansion devices 33a, 33b, and 33c. Such an expansion device may include an LEV valve.

When the air conditioner configured as described above operates in the cooling mode, the refrigerant compressed at high temperature in the compressor (11) flows into the outdoor heat exchanger (12). At this time, the refrigerant flowing into the outdoor heat exchanger is condensed while exchanging heat with the outdoor air as the outdoor fan 13 is rotated.

The refrigerant thus condensed flows into the distributor 20 through the first refrigerant pipe 21 and the refrigerant introduced into the distributor is introduced into the respective indoor units 21a, 21b, 21c through the distribution pipes 21a, 21b, 21c of the first refrigerant pipe 21, (30a, 30b, 30c).

At this time, when all the indoor units are operated, the distributor 20 supplies the refrigerant to all the indoor units. In addition, when only a part of the indoor units is operated, refrigerant is supplied only to a part of the indoor units by closing the expansion unit of the remaining indoor units.

The refrigerant introduced into the indoor unit is expanded while passing through the expansion devices 33a, 33b and 33c, and the refrigerant thus expanded flows into the indoor heat exchangers 31a, 31b and 31c at a low temperature. At this time, the indoor fans 32a, 32b, and 32c are rotated to exchange heat between the refrigerant of the indoor heat exchangers 31a, 31b, and 31c and the indoor air. The generated cold air is discharged into the indoor space to cool the indoor space.

The refrigerant of the indoor heat exchanger is discharged to the distributor 20 through the distribution pipes 22a, 22b and 22c of the second refrigerant pipe 22 and the refrigerant of the distributor is discharged through the second refrigerant pipe 22 And then flows into the outdoor unit 10 again. At this time, the refrigerant flowing into the outdoor unit passes through the accumulator 14 and is recovered by the compressor 11.

By continuously performing this series of processes, the indoor space is cooled.

Meanwhile, when the air conditioner is operated in the heating mode, the refrigerant compressed at the high temperature by the compressor 11 flows into the distributor 20 through the second refrigerant pipe 22, And flows into the indoor units 30a, 30b, and 30c through the distribution pipes 22a, 22b, and 22c.

At this time, the distributor 20 supplies the refrigerant to all the indoor units 30a, 30b, and 30c, not only when all the indoor units are operated but also when only some indoor units 30a and 30c among the indoor units are operated.

At this time, high-temperature refrigerant flows into the indoor heat exchangers 31a and 31c of the indoor units 30a and 30c, and as the indoor indoor fans 32a and 32c rotate, the high-temperature refrigerant and the indoor air Heat exchanged. The refrigerant thus heat-exchanged is expanded while passing through the expansion devices 33a and 33c, and the refrigerant thus expanded flows into the distributor 20 through the branch pipes 21a and 21c of the first refrigerant pipe. At this time, since the expansion device 33b is closed in a part of the non-operated (OFF) indoor unit 30b, the refrigerant becomes concentrated in the indoor unit 30b and the inflow pipe 22b. Therefore, the liquid droplet is generated.

The refrigerant introduced into the distributor 20 flows into the outdoor heat exchanger 12 through the first refrigerant pipe 21 and the refrigerant heat-exchanged with the outdoor air in the outdoor heat exchanger passes through the accumulator 14 to the compressor 11, Respectively.

By continuously performing this series of processes, the indoor space is heated.

FIG. 2 is a view of an indoor unit of an air conditioner according to an embodiment of the present invention, and FIG. 3 is a block diagram of an air conditioner according to an embodiment of the present invention.

Referring to FIGS. 2 and 3, the indoor unit 30 of the air conditioner of the present embodiment includes an indoor heat exchanger 31, an indoor fan 32 for flowing air to the indoor heat exchanger, At least one of an expansion device 33 for expanding the refrigerant, temperature sensing sensors 34 and 35 for sensing the temperature of the refrigerant in the indoor heat exchanger 31, and a control unit 36 for controlling the flow of the refrigerant in the indoor unit All are included.

The indoor heat exchanger (31) exchanges heat between the refrigerant flowing and the room air.

The indoor fan (32) is provided at one side of the indoor heat exchanger so that the indoor air flows through the indoor heat exchanger.

The expansion device (33) expands the refrigerant discharged from the indoor heat exchanger and can control the flow rate of the refrigerant flowing.

The temperature sensing sensors 34 and 35 sense an inlet side temperature T1 of the indoor heat exchanger 31 and an outlet side temperature T2 of the indoor heat exchanger 31. [ The first temperature sensor 34 located at the inlet side of the indoor heat exchanger 31 senses the inlet side temperature T1 and the second temperature sensor 35 for the outlet side of the indoor heat exchanger 31 ) Senses the outlet-side temperature T2.

Since the inlet temperature T1 is sensed at the point where the refrigerant is drawn into the outdoor heat exchanger 31, it can be regarded as the inlet temperature. The outlet temperature T2 is a temperature at which the refrigerant is discharged from the outdoor heat exchanger 31 It can be said to be the discharge temperature.

The control unit 36 can estimate the supercooling degree through the inlet side temperature T1 of the indoor heat exchanger and the outlet side temperature T2 of the indoor heat exchanger obtained from the temperature sensing sensors 34 and 35. [

For example, the difference between the outlet-side temperature T2 and the inlet-side temperature T1 can be estimated as the supercooling degree.

As another example, the saturation temperature Tb flowing through the indoor unit can be calculated through the inlet side temperature T1 and the subcooling degree can be estimated from the saturation temperature Tb and the outlet side temperature T2 . The saturation temperature Tb may be selectively applied to either the inlet side temperature T1 of the indoor unit and the discharge pipe temperature T2 or to apply an arithmetic average or a weighted average thereof.

The degree of supercooling makes it possible to determine the state of the refrigerant in the non-operation indoor unit. That is, when the supercooling degree is sufficiently large, the refrigerant is in a liquid state, so that noise caused by the expansion can be small when passing through the expansion device. On the other hand, when the refrigerant is not overcooled or undercooling is insufficient, the refrigerant may be in a two-phase state in which the liquid phase and the gaseous phase refrigerant coexist. Therefore, when the refrigerant passes through the expansion device, Can cause a large noise due to the noise.

Further, the control unit 36 can determine whether or not the liquid state is eliminated in the indoor heat exchanger through the discharge temperature of the compressor, the inlet-side temperature (T1), and the outlet-side temperature (T2).

For example, whether or not the liquid level is eliminated can be determined by changing the inlet side temperature T1 and the outlet side temperature T2 of the non-operated indoor unit. In other words, when the liquid level is eliminated, the inlet side temperature T1 and the outlet side temperature T2 are increased. However, when the liquid level is not removed, the amount of refrigerant flowing into the indoor heat exchanger and the flow pipe is large, .

As another example, it can be determined that a liquid jam occurs when the refrigerant discharge temperature of the compressor is higher than the theoretical discharge temperature by a certain temperature or more. Here, the theoretical discharge temperature means the discharge temperature of the compressor when the liquid level of the refrigerant does not occur under the same cooling / heating condition. That is, when only a few indoor units are operated in the same number, it is the compressor discharge temperature when all of the refrigerant circulates in accordance with the cooling / heating cycle without refrigerant loss due to the liquid accumulation in the indoor unit. Since the amount of refrigerant flowing into the indoor unit increases and the amount of refrigerant flowing into the compressor decreases, the refrigerant discharge temperature of the compressor can be increased by compressing a small amount of refrigerant into the same compressor.

FIG. 4 is a diagram illustrating a control method of an air conditioner according to an embodiment of the present invention, and FIG. 5 is a diagram illustrating an operation of an indoor fan and an expansion device of an air conditioner according to an embodiment of the present invention.

Referring to FIGS. 4 and 5, when the heating operation of the air conditioner is partially started, the control unit operates the compressor 11 at a predetermined normal frequency (S1). At this time, the refrigerant discharged from the compressor is supplied to at least two indoor units 30a, 30b, and 30c of the indoor units 30a and 30c. Thereby, the heating operation is performed in a part of the cooling cycle (S2).

At this time, the controller opens the expansion device of the non-operated outdoor (outdoor) unit at the first opening degree (S3). The first opening degree may be 70 pls. However, the opening degree of the expansion device is set to be a constant section of the range of the opening degree to reduce the expansion noise of the refrigerant in consideration of the number of the non-operating (indoor) indoor units and / .

Then, the inlet side temperature T1 and the discharge temperature T2 of the indoor unit are measured (S4). The supercooling degree can be estimated using the difference between the outlet side temperature T2 and the inlet side temperature T1.

It is determined whether the supercooling degree is equal to or higher than a first set temperature (S5). If the subcooling degree of the refrigerant is equal to or higher than the first set temperature, the refrigerant can be in a liquid state rather than an ideal gas. For example, the first set temperature may be 5 degrees.

If the estimated supercooling degree in step S5 is less than the first temperature, the indoor fan is operated at the first speed (S6). Since the indoor fan flows air to the indoor heat exchanger, the indoor refrigerant can be supercooled inside the indoor heat exchanger. However, if the first speed is high, the indoor fan may be driven at a set rotation speed that is less than a preset noise level because the indoor fan may generate noise, RPM < / RTI >

Thereafter, the inlet-side temperature T1 and the outlet-side temperature T2 are measured again in accordance with step S4, and the degree of supercooling is judged again in accordance with step S5.

If the supercooling degree is equal to or higher than the first set temperature in step S5, the expansion device is opened by the second degree of opening (S7). The second degree of opening may be larger than the first degree of opening, and as the opening degree of the expansion device is increased, the amount of refrigerant passing through the expansion device is increased, thereby eliminating the phenomenon of liquid accumulation. The second opening degree may be 120 pls.

On the other hand, the indoor fan is stopped (S8). This is to stop the indoor fan for subcooling the refrigerant because the subcooling degree is sufficient.

Further, the temperature T1 on the inlet side and the temperature T2 on the outlet side of the indoor unit are measured (S9).

Then, it is determined whether or not the indoor unit is dislodged through the measured inlet-side temperature T1 and outlet-side temperature T2 (S10). The disappearance of the liquid level can be judged by a change in the inlet-side temperature (T1) and the outlet-side temperature (T2). That is, if the liquid level is eliminated, since the amount of refrigerant in the indoor heat exchanger is reduced, the temperature T1 on the inlet side and the temperature T2 on the outlet side of the indoor unit can rise.

The liquid level is not eliminated in step S10, and the inlet side temperature T1 and the outlet side temperature T2 are measured again in step S9. At this time, the opening degree of the expansion device is still maintained in the second opening degree.

When it is determined in step S10 that the liquid level has been eliminated, the expansion device is again opened by the first degree opening.

According to the embodiment of the present invention, the subcooling degree is estimated through the temperature of the refrigerant, and the expansion device is controlled so as to increase the opening degree in a state in which the subcooling degree is sufficiently undercooled, so that only the liquid refrigerant can pass through the expansion device, When the supercooling degree is not sufficient, the indoor fan is operated at the first speed and cooled by the indoor heat exchanger, so that the supercooling degree of the refrigerant can be increased quickly.

Accordingly, by driving the indoor fan at the first speed, the supercooling degree can be increased rapidly, and the sufficiently low supercooled refrigerant is passed through the expansion device, so that the noise can be reduced. That is, there is an advantage in that the indoor fan can be driven to quickly solve the liquid sticking phenomenon.

Claims

Performing a heating operation by supplying refrigerant to at least two indoor units of at least two indoor units;
Calculating an undercooling degree by measuring an inlet side temperature and an outlet side temperature of the indoor heat exchanger of the non-operation indoor unit in which the heating operation is not performed; And
And driving the indoor fan provided in the non-operation indoor unit based on the supercooling degree.

The method according to claim 1,
And the subcooling degree is increased by driving the indoor fan when the subcooling degree is lower than the first set temperature.

3. The method of claim 2,
Further comprising increasing or decreasing an opening degree of the expansion device of the non-operation indoor unit based on the increased subcooling degree.

The method of claim 3,
And increasing the opening degree of the expansion device to allow the refrigerant to pass through the indoor heat exchanger when the increased subcooling degree is equal to or higher than the first set temperature.

5. The method of claim 4,
In the process of increasing the opening degree of the expansion device,
And stopping the indoor fan.

The method according to claim 1,
Detecting an inlet-side temperature and an outlet-side temperature of the indoor heat exchanger, and determining whether the non-operating indoor unit is in a liquid state according to the sensed information; And
Decreasing the opening of the expansion device when the liquid level is relieved;
Further comprising the steps of:

3. The method of claim 2,
Wherein the indoor unit is driven at a predetermined number of revolutions matched with occurrence of noise below a predetermined level,
Wherein the set number of revolutions of the indoor fan is 0 to 200 RPM.

In the indoor unit of the simultaneous-type air conditioner,
An indoor heat exchanger for exchanging heat between the refrigerant and the indoor air;
An indoor fan that flows the air toward the indoor heat exchanger;
A temperature sensor located in an inlet pipe and a discharge pipe of the indoor heat exchanger;
A valve disposed in the discharge pipe to selectively flow the refrigerant; And
And a control unit for controlling the indoor fan,
Wherein at least a part of the indoor unit performs a heating operation and the rest of the indoor unit is turned off so that the indoor fan of the indoor unit is driven so that the refrigerant in the indoor heat exchanger is supercooled.

9. The method of claim 8,
And estimates the degree of supercooling through the temperature sensor and drives the indoor fan when the supercooling degree is lower than a predetermined temperature.

9. The method of claim 8,
Wherein the valve increases the degree of opening of the valve when the supercooling degree of the refrigerant in the indoor heat exchanger is equal to or higher than a predetermined temperature.

9. The method of claim 8,
Wherein the valve is an electronic expansion valve (EEV).

10. The method of claim 9,
Wherein the indoor fan is rotated at an RPM of 0 or more and 200 or less.