KR102243654B1 - Air conditioner - Google Patents

Abstract

The present invention relates to an air conditioner, and more specifically, according to an aspect of the present invention, a compressor for compressing a refrigerant and a mixed fluid of refrigerant and oil discharged from the compressor are introduced, and oil is extracted from the mixed fluid. An oil separator for separating and provided at a predetermined height of the oil separator, an oil level sensor for detecting an oil level inside the oil separator, an operating time of the compressor, and the compressor based on oil level information measured from the oil level sensor There is provided an air conditioning apparatus including a control unit for controlling the number of revolutions of operation.

Description

Air conditioner {Air conditioner}

The present invention relates to an air conditioner, and more particularly, to an air conditioner capable of preventing unnecessary oil recovery operation and minimizing energy loss.

In general, an air conditioner is a device that cools or heats an indoor space such as a residential space, a restaurant, or an office.

In addition, the air conditioner may include an outdoor unit installed in an outdoor space and an indoor unit installed in an indoor space.

Here, the outdoor unit includes a compressor for compressing the refrigerant, an outdoor heat exchanger for heat exchange between outdoor air and the refrigerant, a blower fan, and various pipes connecting the compressor and the indoor unit. In addition, the indoor unit may include an indoor heat exchanger and an expansion valve for heat exchange between indoor air and refrigerant.

The air conditioner includes an oil separator for separating oil from the refrigerant discharged from the compressor and recovering it back to the compressor.

The compressor and the oil separator are respectively connected by two pipes. Specifically, the pipe includes an inlet pipe through which refrigerant and oil discharged from the compressor flow in, and a recovery pipe through which the oil separated by the oil separator is recovered to the compressor.

When the oil storage space of the oil separator runs out of oil during the operation of the air conditioner, the amount of oil recovered by the compressor decreases. Accordingly, damage to the compressor occurs.

1 is a graph for explaining an oil recovery operation of a general air conditioner.

Conventional air conditioners have a structure in which the oil level inside the oil separator cannot be checked. Therefore, the forced oil recovery operation is performed every predetermined time (eg, 8 hours).

However, periodic oil recovery operation generates indoor unit refrigerant noise and increases the number of cooling/heating stops.

An object of the present invention is to provide an air conditioner capable of detecting an oil level inside an oil separator.

In addition, an object of the present invention is to provide an air conditioner capable of preventing unnecessary oil recovery operation.

In addition, an object of the present invention is to provide an air conditioner capable of reducing the refrigerant noise of the indoor unit and the number of stopping the cooling/heating operation.

In addition, an object of the present invention is to provide an air conditioner capable of reducing energy loss and improving comfort.

In order to solve the above problems, according to an aspect of the present invention, a compressor for compressing a refrigerant and a mixed fluid of refrigerant and oil discharged from the compressor are introduced, and an oil separator for separating oil from the mixed fluid and It is provided at a predetermined height of the oil separator and controls the operating speed of the compressor based on an oil level sensor for sensing the oil level inside the oil separator, an operating time of the compressor, and oil level information measured from the oil level sensor. There is provided an air conditioning apparatus including a control unit for doing so.

In addition, when the operating time of the compressor is greater than or equal to a first time, the discharge superheat of the compressor is greater than or equal to the first temperature, and the oil level sensor does not detect the oil level, the operating rotation speed of the compressor Can increase

In addition, the first time may be 10 minutes, and the first temperature may be 10°.

In addition, when the time during which the oil level sensor does not detect the oil level is longer than the second time, the control unit may increase the operating speed of the compressor.

In addition, when the oil level sensor does not detect the oil level continuously for a second period of time, the control unit may increase the operating speed of the compressor.

Also, the second time may be 30 minutes.

In addition, the mounting height of the oil level sensor may be determined based on the required oil amount and safety factor of the compressor.

In addition, the mounting height of the oil level sensor may increase in proportion to the required oil amount of the compressor.

In addition, the oil level sensor may be a capacitive sensor.

In addition, according to another aspect of the present invention, at least one compressor for compressing a refrigerant; A gas engine for driving the compressor; An oil separator for introducing a mixed fluid of refrigerant and oil discharged from the compressor and separating the oil from the mixed fluid; An oil level sensor provided at a predetermined height of the oil separator and configured to sense an oil level inside the oil separator; And a control unit for controlling the number of rotations of the compressor based on at least two of the oil level information measured from the oil level sensor, the operating time of the compressor, and the discharge superheat of the compressor. do.

In addition, when the operating time of the compressor is greater than or equal to a first time, the discharge superheat of the compressor is greater than or equal to the first temperature, and the oil level sensor does not detect the oil level, the operating speed of the compressor is increased. The gas engine can be controlled so as to be.

In addition, when the time during which the oil level sensor does not detect the oil level is longer than the second time, the control unit may control the gas engine to increase the number of rotations of the compressor.

In addition, the controller may control the gas engine to increase the number of rotations of the compressor when the oil level sensor does not detect the oil level continuously for a second time.

As described above, the air conditioner related to at least one embodiment of the present invention has the following effects.

The oil level inside the oil separator can be detected through the oil level sensor provided inside the oil separator.

In addition, the oil recovery operation can be actively performed according to the oil level measured through the oil level sensor. Therefore, unnecessary oil recovery operation can be prevented.

In addition, it is possible to reduce the refrigerant noise of the indoor unit and the number of stopping the cooling/heating operation by preventing unnecessary oil recovery operation.

In addition, it is possible to improve the continuous operation rate of the air conditioner, reduce energy loss, and improve comfort.

1 is a graph for explaining an oil recovery operation of a general air conditioner.
2 is a block diagram of an air conditioner related to an embodiment of the present invention.
3 is a block diagram of a main part of the air conditioner shown in FIG. 2.
4 is a block diagram of an air conditioner related to an embodiment of the present invention.
5 is a flow chart showing a control method of an air conditioner according to an embodiment of the present invention.

Hereinafter, an air conditioner according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The accompanying drawings show exemplary forms of the present invention, which are provided only to describe the present invention in detail, and thus the technical scope of the present invention is not limited thereto.

FIG. 2 is a block diagram of an air conditioner according to an embodiment of the present invention, and FIG. 3 is a block diagram of a main part of the air conditioner shown in FIG. 2.

Referring to FIG. 2, the air conditioner 1 may include an outdoor unit and one or more indoor units 40 connected to the outdoor unit. The outdoor unit and one or more indoor units 40 may be connected through a refrigerant piping unit 80.

In addition, the air conditioner 1 includes a compressor 10 for compressing refrigerant, an outdoor heat exchanger 50 for heat exchange between outdoor air and refrigerant, an expansion valve 71, and indoor heat exchange for heat exchange between indoor air and refrigerant. It includes a cooling/heating cycle including a group (not shown).

A compressor 10, an outdoor heat exchanger 50, and an expansion valve 71 may be provided in the outdoor unit, respectively. In addition, an outdoor fan 130 may be provided on the side of the outdoor heat exchanger 50. In addition, the indoor unit 40 may be provided with an indoor heat exchanger and an indoor fan, respectively.

In addition, the air conditioner 1 may further include an accumulator 30 provided on the side of the compressor 10. The accumulator 30 performs a function of transferring only the gaseous refrigerant to the compressor 10 by separating the liquid refrigerant from the gaseous refrigerant.

Meanwhile, the air conditioner 1 may include a flow path switching valve for cooling or heating an indoor space by selectively supplying a refrigerant in both directions.

In one embodiment, the flow path switching valve may include a 4-way valve (60). The four-way valve 60 is configured to select and supply the refrigerant introduced to one side in an arbitrary direction.

The air conditioner 1 includes an oil separator 20 for separating the oil discharged from the compressor 10 and recovering the separated and/or stored oil back to the compressor 10.

The oil separator 20 receives a mixed fluid of refrigerant and oil discharged from the compressor 10 and separates oil from the mixed fluid. A predetermined amount of oil is stored in the compressor 10.

To this end, a storage space having a predetermined volume is provided inside the oil separator 20. The storage space serves to store a predetermined amount of oil separated in the oil separator 20.

When the compressor 10 is in an operating state, if the amount of oil inside the compressor 10 becomes insufficient, the compressor 10 may be damaged or the air conditioner 1 may be stopped.

The mixed fluid of refrigerant and oil discharged from the compressor 10 is delivered to the oil separator 20 through the inlet pipe 18. In addition, the oil separated by the oil separator 20 is recovered to the compressor 10 through a recovery pipe 82.

Meanwhile, the recovery pipe 82 may be provided with one or more valves for selectively opening and closing the recovery pipe 82. The valve may include a solenoid valve 73.

Meanwhile, the air conditioner 1 may include a plurality of compressors 10-1 and 10-2. In this case, the number of inlet pipes and return pipes may increase depending on the number of compressors.

Referring to FIG. 3, when there are two compressors, the recovery pipe 82 may be branched to each of the compressors 10-1 and 10-2, or may be connected to each of the two recovery pipes. In addition, when a plurality of compressors are provided, the plurality of compressors 10-1 and 10-2 may be connected to one oil separator 20.

In addition, the air conditioner 1 includes an oil level sensor 90 provided in the oil separator 20. The oil level sensor 90 performs a function of detecting the oil level inside the oil separator.

Specifically, the oil level sensor 90 may detect an oil level corresponding to the amount of oil stored in the storage space inside the oil separator 20.

Referring to FIG. 3, the oil level sensor 90 is provided at a predetermined height inside the oil separator 20. In this document, the height h of the oil separator 20 in which the oil level sensor 20 is located is substantially the same as the direction L in which the oil level increases in the storage space of the oil separator 20.

The oil level sensor 90 may include a capacitive sensor. In one embodiment, the capacitive sensor may detect the level of the fluid through a change in dielectric constant between the two plates.

In addition, the oil level sensor 90 may detect not only the oil level but also the refrigerant level. In one embodiment, when the mixed fluid of refrigerant and oil flows into the oil separator 20, the oil level sensor 90 may detect the level of the mixed fluid.

In addition, the oil level sensor 90 may detect the fluid level at the mounting height h.

Specifically, when the fluid (oil) level increases above the mounting height h of the oil level sensor 90, the oil level sensor 90 may detect the fluid (oil) level. In contrast, when the fluid (oil) level is positioned lower than the mounting height h of the oil level sensor 90, the oil level sensor 90 cannot detect the fluid (oil) level.

In summary, the oil level sensor 90 can detect the oil level only when the oil level increases above a corresponding height at which the oil level sensor 90 is mounted. Therefore, it is important to determine the mounting height h of the oil level sensor 90 provided inside the oil separator 20.

In one embodiment, the mounting height h of the oil level sensor 90 may be determined based on the required oil amount and safety factor of the compressor 10. For example, when the required oil amount of the compressor 10 is 350 cc and the safety factor is 1.5, the oil level sensor 90 may be mounted at a height such that the volume of the storage space inside the oil separator 20 is 500 cc.

Here, the mounting height h of the oil level sensor 90 may increase in proportion to the required oil amount of the compressor. In addition, the mounting height h of the oil level sensor 90 may increase in proportion to the safety factor.

On the other hand, when the compressor 10 is composed of a plurality of compressors (10-1, 10-2), the height (h) of the oil level sensor 90 is required for each compressor (10-1, 10-2) It can be determined based on the amount of oil, the number of compressors, and the safety factor.

For example, when two compressors (10-1, 10-2) have the same required oil quantity, and the required oil quantity of each compressor (10-1, 10-2) is 350cc, and the safety factor is 1.5, the oil level The sensor 90 may be mounted at a height such that the volume of the storage space inside the oil separator 20 is 1000 cc.

4 is a block diagram of an air conditioner related to an embodiment of the present invention.

The air conditioner 1 includes a control unit 200 for controlling the operating speed of the compressor 10 based on the operating time of the compressor 10 and the oil level information measured from the oil level sensor 90. Includes.

In addition, the air conditioner 1 may include a timer 201 for calculating an operating time of the compressor 10. In addition, the air conditioner 1 may include at least one of one or more temperature sensors 202 and one or more pressure sensors for measuring the discharge superheat of the compressor 10.

In addition, the control unit 200 may control the number of rotations of the compressor 10 and perform ON/OFF control of the compressor 10. In addition, the control unit 200 may control various valves 70 (71, 72, 73). In addition, the control of each valve may include on/off and opening degree control of the corresponding valve.

On the other hand, the oil discharged from the compressor 10 is separated in a considerable part inside the oil separator 20, but most of the oil that was not separated through the oil separator 20 is located in the pipe part (A) connecting the outdoor unit and the indoor unit. do.

In addition, when the amount of oil that has flowed out to the piping unit 90 increases according to the operating time or operating condition of the compressor 10, the oil shortage in the compressor 10 occurs.

Here, in order to prevent a shortage of oil in the compressor 10, the control unit 200 performs an oil recovery operation.

The oil recovery operation means increasing the number of rotations of the compressor 10. Specifically, the flow rate of the refrigerant discharged from the compressor 10 is increased by increasing the operating rotation speed of the compressor. As a result, the oil accumulated in the pipe portion (eg, A) due to the increased refrigerant flow rate may be recovered to the compressor 10 again along the refrigerant with an increased flow rate.

In summary, the control unit 200 performs an oil recovery operation based on the operation time of the compressor 10 and the oil level information measured from the oil level sensor 90.

In addition, the control unit 200 is based on at least two or more of the oil level information measured from the oil level sensor 90, the operating time of the compressor 10, and the discharge superheat of the compressor 10. The driving speed can be controlled.

Hereinafter, each case will be described in detail.

Meanwhile, although the oil storage space of the oil separator 20 is a space for storing a predetermined amount of oil, a refrigerant may occupy a partial volume in some cases.

As described above, the oil level sensor 90 can detect not only the oil level but also the refrigerant level. Accordingly, even when the oil level sensor 90 detects the refrigerant level, the control unit 200 may determine that the amount of oil stored in the oil separator 20 is sufficient.

To prevent this, the oil level detection may be performed after the operation of the compressor 10 is stabilized.

Specifically, when the operation of the compressor 10 is stabilized, it can be trusted that the fluid level sensed through the oil level sensor 20 is the oil level inside the oil separator 20.

To this end, when the operating time of the compressor 10 is greater than or equal to a first time and the discharge superheat of the compressor 10 is greater than or equal to the first temperature, the oil level sensor 90 Level can be detected.

In contrast, when the operation of the compressor 10 is started, the control unit 200 may ignore the level information while receiving the level information from the oil level sensor 90.

Thereafter, when the operating time of the compressor 10 is greater than or equal to a first time and the discharge superheat of the compressor 10 is greater than or equal to the first temperature, the control unit 200 determines the oil level sensor 90 ) Through the oil level information sensed from, it is possible to control the operating speed of the compressor 10.

Here, a case where the operating time of the compressor 10 is greater than or equal to the first time and the discharge superheat of the compressor 10 is greater than or equal to the first temperature may be referred to as a state in which the compressor 10 is stabilized. In one embodiment, the first time may be 10 minutes, and the first temperature may be 10°.

Specifically, when the operating time of the compressor 10 is 10 minutes or more and the discharge superheat of the compressor 10 is 10° or more, it may be determined that the operating state of the compressor 10 is stabilized.

At this time, when the operating time of the compressor 10 is greater than or equal to the first time, the discharge superheat of the compressor 10 is greater than or equal to the first temperature, and the oil level sensor 90 does not detect the oil level, the The controller 200 may determine that the amount of oil recovered by the compressor 10 is insufficient.

Accordingly, the control unit 200 may perform an oil recovery operation.

In summary, the control unit 200, the operating time of the compressor 10 is more than a first time, the discharge superheat of the compressor 10 is equal to or higher than the first temperature, and the oil level sensor 90 is If it is not detected, it is possible to increase the operating speed of the compressor 10.

On the other hand, the controller 200 may increase the operating speed of the compressor 10 when the time during which the oil level sensor 90 does not detect the oil level is longer than the second time.

Specifically, when the oil level sensor 90 does not detect the oil level, it may be determined that the amount of oil inside the oil separator is insufficient. In addition, the insufficient amount of oil stored in the oil separator 20 may be determined as insufficient oil recovered by the compressor 10.

As described above, the mounting height h of the oil level sensor 90 may be determined based on the required oil amount and safety factor of the compressor 10.

Specifically, even when the oil level sensor 90 does not detect the oil level, oil may be delivered to the compressor 10 for a predetermined time.

Accordingly, when the time during which the oil level sensor 90 does not detect the oil level is longer than the second time, the control unit 200 may perform an oil recovery operation.

In one embodiment, the second time may be larger than the first time. Also, the second time may be 30 minutes.

Meanwhile, when the oil level sensor 90 does not detect the oil level continuously for a second period of time, the control unit 200 may increase the operating speed of the compressor 10.

In order to prevent unnecessary oil recovery operation, the control unit 200 may perform the oil recovery operation only when the oil level sensor 90 does not detect the oil level continuously for a second time.

5 is a flow chart showing a control method of the air conditioner 1 according to an embodiment of the present invention.

Referring to FIG. 5, the control method (hereinafter, the control method) of the air conditioner may include the operation start step (S100) of the compressor 10.

In addition, the control method may include a compressor 10 operating time and a compressor 10 discharge superheat measurement step (S101). The measuring step S101 is a step for determining whether the operating state of the compressor 10 is in a stable state.

In addition, the control method includes a step (S102) of determining whether the operating time of the compressor 10 is greater than or equal to a predetermined time and the discharge superheat of the compressor is greater than or equal to a predetermined temperature. As described above, when the operating time of the compressor is greater than or equal to the first time (eg, 10 minutes) and the discharge superheat of the compressor is greater than or equal to the first temperature (eg, 10°), the control unit 200 ) May determine that the operating state of the compressor 10 is a stabilization state.

In addition, the control method includes an oil level sensing step (S103).

In addition, the control method includes a step S104 of determining whether a predetermined time has elapsed while the oil level is not detected. As described above, the controller 200 may perform an oil recovery operation when the oil level sensor 90 does not detect the oil level continuously for a second period of time (eg, 30 minutes).

When a predetermined time elapses while the oil level is not detected, the oil recovery operation step S104 may be performed.

On the other hand, the air conditioner 1 related to the present invention can be applied to a gas heat pump (GHP).

Referring to FIG. 2, a gas heat pump system uses a gas engine 100 rather than an electric motor to drive the compressor 10. The gas engine 100 performs a function of driving the compressor 100.

The gas heat pump system can compress a large amount of refrigerant at high temperature and high pressure, so it is widely used in air conditioners used in industrial or large buildings that require a large-capacity compressor 10.

The gas heat pump may be connected to one or more indoor units 40 through a refrigerant piping unit 80. In addition, the gas heat pump may include a compressor 10, an oil separator 20, a four-way valve 60, and an outdoor heat exchanger 50.

In addition, the gas heat pump may include a cooling water line 150 for cooling the gas engine 100, a radiator 120 through which the cooling water line passes, and a pump 150 for circulating the cooling water. In addition, the gas heat pump may include a waste heat recovery heat exchanger 110 for heat exchange between an array of the gas engine 100 (coolant line) and a refrigerant.

Meanwhile, in the case of a gas heat pump, the driving of the compressor 10 is determined by the gas engine 100. In addition, during the oil recovery operation, the number of rotations of the compressor 10 may be determined by the gas engine 100.

Accordingly, when the oil recovery operation is performed, the controller 200 may control the gas engine 100 to increase the number of revolutions of the compressor 10. In one embodiment, the output and/or the number of revolutions of the gas engine 100 may be increased.

Specifically, when the operating time of the compressor is more than a first time, the discharge superheat of the compressor 10 is greater than or equal to the first temperature, and the oil level sensor does not detect the oil level, The gas engine 100 may be controlled to increase the number of rotations of the compressor 10.

In addition, the control unit 200 controls the gas engine 100 to increase the number of revolutions of the compressor 10 when the oil level sensor 90 does not detect the oil level for a second time or longer. can do. As described above, the second time may be greater than the first time.

In addition, when the oil level sensor 90 does not detect the oil level continuously for a second time, the control unit 200 controls the gas engine 100 to increase the number of rotations of the compressor 10. I can.

1: air conditioner 10: compressor
20: oil separator 30: accumulator
40: indoor unit 50: outdoor heat exchanger
60: 4-way valve 70: valve
80: refrigerant piping part 90: oil level sensor
100: gas engine 200: control unit

Claims (14)

A compressor for compressing a refrigerant;
An oil separator for introducing a mixed fluid of refrigerant and oil discharged from the compressor and separating the oil from the mixed fluid;
An oil level sensor provided at a predetermined height of the oil separator and configured to sense an oil level inside the oil separator; And
A control unit for determining whether to stabilize the operation of the compressor based on the operation time of the compressor and the discharge superheat of the compressor, and controlling the operation speed of the compressor based on the oil level information measured from the oil level sensor; Including,
When the operating time of the compressor is greater than or equal to a first time and the discharge superheat of the compressor is greater than or equal to the first temperature, the control unit determines that the operation of the compressor is stabilized, and the oil level sensor does not detect the oil level. In the air conditioner, characterized in that increasing the operating speed of the compressor. delete The method of claim 1,
The first time is 10 minutes, and the first temperature is 10°. The method of claim 1,
The control unit, when the oil level sensor does not detect the oil level is more than a second time, the air conditioner, characterized in that to increase the number of rotations of the compressor. The method of claim 4,
The control unit, when the oil level sensor does not detect the oil level continuously for a second period of time, the air conditioner, characterized in that to increase the operating speed of the compressor. The method of claim 4,
The second time is an air conditioner, characterized in that 30 minutes. The method of claim 1,
An air conditioner, characterized in that the mounting height of the oil level sensor is determined based on a required oil amount and a safety factor of the compressor. The method of claim 7,
An air conditioner, characterized in that the mounting height of the oil level sensor increases in proportion to the required oil amount of the compressor. The method of claim 1,
The air conditioner, characterized in that the oil level sensor is a capacitive sensor. One or more compressors for compressing a refrigerant;
A gas engine for driving the compressor;
An oil separator for introducing a mixed fluid of refrigerant and oil discharged from the compressor and separating the oil from the mixed fluid;
An oil level sensor provided at a predetermined height of the oil separator and configured to sense an oil level inside the oil separator; And
Including; a control unit for controlling the operating speed of the compressor based on at least two or more of the oil level information measured from the oil level sensor, the operating time of the compressor, and the discharge superheat of the compressor; and
When the operating time of the compressor is greater than or equal to a first time, the discharge superheat of the compressor is greater than or equal to the first temperature, and the oil level sensor does not detect the oil level, the control unit is configured to increase the operating speed of the compressor. An air conditioner for controlling a gas engine. delete The method of claim 10,
The controller controls the gas engine to increase the number of rotations of the compressor when the time during which the oil level sensor does not detect the oil level is longer than a second time,
The second time is an air conditioner, characterized in that greater than the first time. The method of claim 12,
And the control unit controls the gas engine to increase the number of rotations of the compressor when the oil level sensor does not detect the oil level continuously for a second period of time. The method of claim 10,
The mounting height of the oil level sensor is determined based on the required oil amount of the compressor, the number of compressors, and a safety factor.

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