KR20060098267A - Airconditioner for a capacity improvement under the overload and control method of it - Google Patents

Abstract

The present invention relates to an air conditioner and a control method for improving the air conditioner performance that can improve the cooling performance when the air conditioner is in an overload state by the rise of the outdoor temperature, the control method, the outdoor heat exchanger If it is detected that the condensation pressure Pd of the refrigerant having passed through 110 is greater than the set pressure α, the condensation pressure is stopped by stopping one of the first compressor 101 and the second compressor 102 that are in operation. And a second step of lowering Pd, and a second step of restarting the stopped compressor when the compressor stop time passes the set time β. At this time, in the first step, the compressor that is stopped is preferably a compressor that has not been stopped in the previous step. Therefore, according to the present invention, it is possible to lower the condensation pressure at the same time while providing the basic cooling capability at the time of overload.

Air conditioner, overload, compressor, condensing pressure, cooling capacity, high pressure switch

Description

Air Conditioner for a capacity improvement under the overload and control method of it}

1 is a schematic diagram showing the configuration of a conventional air conditioner.

Figure 2 is a schematic diagram showing the configuration of an air conditioner for improving the performance during overload according to the present invention.

3 is a flowchart illustrating a control method of an air conditioner for improving performance when overloaded according to the present invention.

* Description of the symbols for the main parts of the drawings *

100 compression unit 101 first compressor

102: second compressor 110: outdoor heat exchanger

120: electronic expansion valve 130: indoor heat exchanger

140, 150 temperature / pressure sensor 200: high pressure switch

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner and a control method thereof, and more particularly, to an air conditioner and a control method for improving the air conditioner when the air conditioner is overloaded due to an increase in outdoor temperature. It is about.

In general, an air conditioner (air conditioner) cools the room by a repetitive action of inhaling hot air in the room, exchanging heat with cold air, and then discharging it into the room (ie, air conditioning space), or (cooling mode), or Refers to a cooling / heating system that heats a room by heating (heating mode). Along with the normal cooling / heating function, the air purifying function of sucking and filtering contaminated air in the room and making it into clean air and re-injecting it into the room, and the dehumidifying function of taking in humid air and making it into dry and dry air It has a back.

1 is a schematic diagram showing the configuration of a conventional air conditioner.

The conventional large-capacity air conditioner shown in FIG. 1 is configured to independently form each refrigerant cycle using two compressors 12 and 22. That is, the first indoor heat exchanger 10, the first compressor 12, the first outdoor heat exchanger 14, and the first capillary tube 16 may mark the first refrigerant cycle (indicated by the solid arrow). The second indoor heat exchanger 20, the second compressor 22, the second outdoor heat exchanger 24, and the second expansion device 26 are configured to form a second refrigerant cycle (indicated by a dashed arrow). It is configured to form.

Referring to the circulation of the refrigerant cycle of the air conditioner by taking the cooling operation as an example, first, the high-temperature, high-pressure gaseous refrigerant compressed by the first and second compressors 12 and 22 is first and second outdoor heat exchange, respectively. Passing through the groups 14 and 24 (acting as a 'condenser' during cooling) the temperature drops and changes to a high pressure low temperature state. Next, the refrigerant changed into a high pressure low temperature state while passing through the first and second outdoor heat exchangers 14 and 24 again passes through the first and second expansion devices 16 and 26, respectively, and is converted into a low pressure low temperature refrigerant. The refrigerant is absorbed by the surrounding heat in the course of passing through the first and second indoor heat exchangers 10 and 20, respectively, and is changed into a refrigerant having a low pressure and high temperature, and then again the first and second compressors ( 12 and 22), the process of inhalation is repeated.

In this case, the air conditioner may drive only the first refrigerant cycle by driving only the first compressor 12, or only driving the second refrigerant cycle by driving only the second compressor 22, depending on the added load. And to drive both the first and second refrigerant cycles by driving both the second compressors 12 and 22, thereby providing two air conditioners each having a different compressor in one room. The same effect can be obtained.

The air conditioner as shown in FIG. 1 has an advantage of realizing a large capacity, but when an overload occurs during cooling operation, an overload protection device inside the compressor or a relief valve, a pressure protection device, operates the compressor. Since it is not driven, there is a disadvantage in that the cooling operation cannot be performed at the time of overload.

In the case of an overload condition in which the outdoor temperature rapidly rises due to heat waves or the like, the amount of heat exchange in the outdoor heat exchangers 14 and 24 is reduced so that the temperature of the refrigerant passing through the outdoor heat exchangers 14 and 24 (ie, the condensation temperature) is a standard. When the condensation temperature rises, the condensation pressure is increased, and the control unit of the air conditioner operates the overload protection device or the relief valve which is a safety device of the compressor to protect the device. Stop operation for a while.

Therefore, in the conventional air conditioner, when an overload condition occurs due to an outdoor temperature rise during the cooling operation, the compressors are automatically stopped by the operation of the safety device, thereby significantly lowering the cooling capacity of the air conditioner.

SUMMARY OF THE INVENTION An object of the present invention is to provide an air conditioner for improving the performance at the time of overload, which can lower the condensation pressure when the condensation pressure due to overload is increased and at the same time improve the cooling ability.

Another object of the present invention is to provide a control method most suitable for achieving the above object.

In order to achieve the above object, the air conditioner for improving the performance at the time of overload according to the present invention, the compression unit 100 composed of the first compressor 101 and the second compressor 102, and in the compression unit 100 An outdoor heat exchanger 110 for condensing the discharged refrigerant and a high pressure switch 200 mounted on the discharge side of the outdoor heat exchanger 110 and detecting whether the condensation pressure of the refrigerant passing therethrough is greater than a set pressure α. ), An electronic expansion valve (120) for phase-converting the refrigerant passing through the outdoor heat exchanger (110) to low temperature and low pressure, an indoor heat exchanger (130) for evaporating the refrigerant by heat exchange with indoor air, and the condensation pressure And a control unit for stopping the operation of one of the first compressor 101 and the second compressor 102 for a predetermined time when it is larger than the set pressure α.

At this time, the high pressure switch 200 is preferably configured to generate an on or off signal to the control unit when it is detected that the condensation pressure Pd is greater than the set pressure α.

In order to achieve the above object, the control method of the air conditioner for improving the performance at the time of overload according to the present invention, the condensation pressure (Pd) of the refrigerant passing through the outdoor heat exchanger 110 is greater than the set pressure (α). Is detected, the first step of lowering the condensation pressure Pd by stopping one of the first compressor 101 and the second compressor 102 in operation, and the stop time of the compressor When elapsed, a second step of restarting the stopped compressor is provided.

At this time, in the first step of stopping one of the two compressors, the compressor that is stopped is preferably a compressor that has not been stopped in the previous step.

Therefore, according to the present invention, it is possible to lower the condensation pressure at the same time while providing the basic cooling capability at the time of overload.

Hereinafter, with reference to the accompanying drawings, it will be described in more detail with respect to the air conditioner and its control method for improving performance during overload according to the present invention.

Figure 2 is a schematic diagram showing the configuration of an air conditioner for improving the performance during overload according to the present invention.

The air conditioner according to the present invention condenses the compressor 100 composed of two compressors, that is, the first compressor 101 and the second compressor 102 and the refrigerant discharged from the compressor 100. An outdoor heat exchanger 110 and a high pressure switch 200 mounted on the discharge side of the outdoor heat exchanger 110 and detecting whether the condensation pressure Pd of the refrigerant having passed therethrough is greater than a set pressure α; Electronic expansion valve 120 for phase-converting the refrigerant passing through the outdoor heat exchanger 110 to low temperature and low pressure, an indoor heat exchanger 130 for evaporating the refrigerant by heat exchange with indoor air, and the condensation pressure Pd. When larger than this set pressure (alpha), it is comprised by the control part (not shown) which stops operation of one of the 1st compressor 101 and the 2nd compressor 102 for a predetermined time.

At this time, the air conditioner, including the compression unit 100 composed of the first compressor 101 and the second compressor 102, the outdoor heat exchanger 110 (ie, the condenser), the electronic expansion valve 120 And the indoor heat exchanger 130 (ie, the evaporator) is configured to form one refrigerant cycle.

The high pressure switch 200 is mounted on the discharge side of the outdoor heat exchanger 110 to detect the condensation pressure of the refrigerant passing through the outdoor heat exchanger 110 during the cooling operation. When the condensation pressure Pd of the refrigerant passing through the outdoor heat exchanger 110 is greater than the set pressure α, the controller generates an on or off signal. By receiving this signal, it is possible to know whether the condensation pressure Pd is greater than or equal to the set pressure α.

On the other hand, as a device for expanding the refrigerant passing through the outdoor heat exchanger 110 to low temperature low pressure, an expansion ratio (LEV) 120 whose opening ratio is adjusted by a controller (not shown) (120) ) Was used. The opening ratio of the electromagnetic expansion valve 120 is a temperature value measured in the appropriate portion of the air conditioner, for example, the temperature / pressure sensors 140 and 150 mounted on the suction pipe and the discharge pipe of the compression unit 100 and On the basis of the pressure value, the superheat degree of the refrigerant cycle is controlled in a range that can be maintained at an appropriate level.

The air conditioner according to the present invention recognizes the pressure of the refrigerant passing through the outdoor heat exchanger 110, that is, when the condensing pressure rises, in order to compensate for the problem that the cooling cycle of the conventional air conditioner is overloaded. At a suitable time, by forcibly stopping one of the two compressors 101 and 102 constituting the compression unit 100, the amount of refrigerant flowing into the outdoor heat exchanger 110 is reduced, resulting in a lower condensation pressure. . At this time, the outdoor heat exchanger 110 is provided to have the same volume as connecting the first and second outdoor heat exchangers (14 and 24 of FIG. 1) of the conventional air conditioner into one. That is, the outdoor heat exchanger is provided in this invention so that the volume may have twice the volume of each conventional outdoor heat exchanger (14 or 24 of FIG. 1).

Under normal conditions, both compressors 101 and 102 are operated to discharge the high temperature and high pressure refrigerant at the same time from the two compressors 101 and 102, and then condense through the outdoor heat exchanger 110 to Is lowered. In this case, the controller (not shown) determines the flow rate of the refrigerant based on the values measured by the temperature / pressure sensors 140 and 150 to adjust the opening angle of the electronic expansion valve 120. Therefore, only the refrigerant determined by the controller (not shown) passes through the electronic expansion valve 120 and then passes through the indoor heat exchanger 130 to lower the temperature of the indoor space, and then flows back into the compression unit 100. do.

However, in a condition where the outdoor temperature is rapidly increased and the air conditioner is overloaded, when the condensation pressure Pd sensed by the high pressure switch 200 rises above the set value α, the controller (not shown) By giving a signal to stop one of the compressors 101 and 102 (eg, the first compressor 101), the cooling operation is performed by only the other compressor (eg, the second compressor 102). Accordingly, since the condensation area used by the refrigerant discharged from one compressor 101 or 102 is doubled compared to the condensation area used by the refrigerant discharged from both compressors 101 and 102, the outdoor heat exchanger ( The condensation pressure of the refrigerant passing through 110 is rapidly lowered so that the safety device of the compressor is not operated so that the air conditioner can be continuously operated without stopping the compressor.

At this time, the overall cooling capacity of the air conditioner is slightly lower than when both compressors are operating, but may have a much improved cooling capacity than the conventional situation in which both compressors are stopped. In this case, the temperature / pressure sensors 140 and 150 sense the changed temperature to adjust the opening angle of the electronic expansion valve 120 to maintain the refrigerant cycle in a stable state.

On the other hand, while driving with one compressor (for example, the second compressor 102) for a predetermined time, and after a certain time has elapsed, the remaining one compressor (for example, the first compressor 101) is operated again to air Restore the conditioner's cooling capacity to the condition before any abnormality in the condensation pressure. Thereafter, the two compressors 101 and 102 are operated until another abnormal signal is generated in the condensation pressure, and when the abnormal signal is generated in the condensation pressure, the previously operated compressor (for example, the second compressor 102) is operated. ) Is stopped and the previously stopped compressor (eg, the first compressor 101) is operated so that the two compressors can maintain the same reliability. At this time, if the abnormality of the condensation pressure occurs frequently, it is possible to easily perform the service by lighting the fault lamp or providing this information to the remote control so that the user can recognize this phenomenon.

3 is a flowchart illustrating a control method of an air conditioner for improving performance when overloaded according to the present invention.

After the air conditioner is turned on (step S100), when the compressor operating condition is satisfied (step S110), both the first compressor 101 (FIG. 2) and the second compressor 102 (FIG. 2) are operated. Start (step S120).

Subsequently, a signal (for example, indicating that the high pressure switch 200 installed in the discharge side of the outdoor heat exchanger 110 in FIG. 2 is detected that the condensation pressure Pd has risen to a value greater than the set pressure α, for example, When the on (or off) signal is sent to the control unit (step S130), the control unit determines whether or not the value stored in the register (1) is "1" (step S140), if it is determined as "1", The first compressor (101 in FIG. 2) and the second compressor (102 in FIG. 2) in operation are stopped (step S150).

The outdoor heat exchanger (110 of FIG. 2) serves to condense the refrigerant by dropping the temperature of the high temperature and high pressure refrigerant discharged from the compression unit by exchanging the refrigerant with outdoor air. However, when the air conditioner is cooled and operated in a state where the outdoor temperature is high, the amount of heat exchange in the outdoor heat exchanger is reduced (that is, since the temperature of the outdoor air itself is high, the amount of heat exchange with the high temperature and high pressure refrigerant is small), The refrigerant passing through this still maintains high temperature and high pressure.

The air conditioner must maintain a balanced temperature and pressure throughout the refrigerant cycle to maintain a constant degree of superheat. When the condensation pressure of the refrigerant passing through the outdoor heat exchanger (110 in FIG. 2) is higher than the required condensation pressure, consequently, It causes the discharge pressure of the compressors to increase. If the discharge pressure of the compressor rises non-ideally, problems such as compressor lock may occur due to internal combustion of the compressor, which may cause a failure of the air conditioner.

In order to prevent such a problem, the air conditioner automatically stops the compressor when the discharge pressure of the compressor is abnormally increased by a compressor safety device or the like. However, in this case, since both compressors in operation are stopped, there is a problem that the cooling capacity of the air conditioner is significantly lowered. In particular, in a state where the outdoor temperature is rapidly rising like midsummer, such a situation frequently occurs. It causes a user's discomfort due to a sudden decrease in cooling ability due to the stop.

Therefore, in the present invention, in order to solve this problem, a high-pressure switch for generating a specific signal, such as on (on) or off (off) at the set pressure (α) on the discharge side of the outdoor heat exchanger (110 in FIG. 2) 2), the high pressure switch (200 in FIG. 2) detects that the condensation pressure is higher than the set pressure (α), and sends a signal to the controller of the air conditioner (not shown). One operation is stopped to reduce the amount of refrigerant flowing into the outdoor heat exchanger (110 in FIG. 2). When the amount of the refrigerant flowing into the outdoor heat exchanger (110 of FIG. 2) is reduced to 1/2, the condensation pressure of the refrigerant passing therethrough is also somewhat lowered.

According to the step S150, since the air conditioner compresses / discharges the refrigerant using only the second compressor 102 (FIG. 2) while the first compressor 101 (FIG. 2) is stopped, the outdoor heat exchanger (110 of FIG. 2). The amount of refrigerant condensed at is lower than when both compressors are used, resulting in a lower condensation pressure. That is, since the outdoor heat exchanger (110 of FIG. 2) condensing the refrigerant discharged from the two compressors condenses only the refrigerant discharged from one compressor, the condensation pressure of the refrigerant passing through the outdoor heat exchanger when using only one compressor is It is lower than the condensation pressure when using both compressors.

Therefore, according to the present invention, it is possible to efficiently lower the non-ideally increased condensation pressure and to allow one compressor to still operate even if the cooling capacity is somewhat reduced, thereby achieving higher cooling capacity than the situation in which both compressors are stopped. have.

Subsequently, the controller stores the value obtained by subtracting "1" from the value stored in the register of step S140 in the register again (therefore, the value stored in the raster becomes "0") (step S160) and the first compressor. It starts to count the stop time of (101 of FIG. 2) (step S170).

Subsequently, when it is confirmed that the first compressor stop time is greater than the set time β (step S180), the controller determines that the condensation pressure is lowered to the standard pressure so that the two compressors may be operated again. By operating the compressor (101 of FIG. 2) again (step S190), the cooling capacity of the air conditioner that has been degraded with the first compressor stop is restored to its original state.

On the other hand, if it is determined in step S140 that the value stored in the register is not "1", that is, "0", this time, the first compressor (101 in FIG. 2) and the second compressor ( 2, the second compressor is stopped (S200). Accordingly, since the amount of the refrigerant flowing into the outdoor heat exchanger (110 of FIG. 2) is reduced to 1/2, the condensation pressure of the refrigerant passing therethrough is lowered. Therefore, the air conditioner can safely operate the compressor without operating the compressor safety device, thereby preventing a sudden decrease in cooling capacity.

Subsequently, the control unit stores the value added by adding "1" from the value stored in the register of step S140 to the register again (therefore, the value stored in the raster becomes "1") (step S210), and the second The counter starts counting down time of the compressor (102 of FIG. 2) (step S220).

Subsequently, when it is confirmed that the second compressor stop time is greater than the set time β (step S230), the controller determines that the condensation pressure is lowered to the standard pressure so that the two compressors may be operated again. By operating the compressor (102 of FIG. 2) again (step S240), the cooling capacity of the air conditioner that has been degraded with the second compressor stop is restored to its original state.

According to the air conditioner and the control method for improving the performance during overload according to the present invention, when the condensation pressure (Pd) is greater than the set pressure (α) to the discharge side of the outdoor heat exchanger, the on (on) or off (off) signal After mounting the generated high pressure switch, if a signal is detected from the high pressure switch that the condensation pressure Pd is greater than the set pressure α, the control unit automatically operates one of the two compressors in operation. Stop it.

Accordingly, the amount of refrigerant flowing into the outdoor heat exchanger can be reduced to 1/2 while maintaining the volume of the outdoor heat exchanger, so that the condensation pressure of the refrigerant passing therethrough is lowered. This, when the condensation pressure is higher than the set pressure, it is possible to achieve the effect of lowering the condensation pressure at the same time as having a basic cooling capacity, compared to the prior art that operates the compressor safety device to stop the operation of all compressors.

In addition, according to the control method of the present invention, when the compressor is stopped, the two compressors can be controlled to be stopped alternately, it is possible to maintain the same reliability according to the operation of the two compressors.

Claims (4)

A compression unit 100 including a first compressor 101 and a second compressor 102; An outdoor heat exchanger (110) for condensing the refrigerant discharged from the compression unit (100); A high pressure switch 200 mounted on the discharge side of the outdoor heat exchanger 110 and detecting whether a condensation pressure of the refrigerant having passed therethrough is greater than a set pressure α; An electronic expansion valve (120) for phase-converting the refrigerant passing through the outdoor heat exchanger (110) to low temperature and low pressure; An indoor heat exchanger (130) for evaporating the refrigerant by heat exchange with the indoor air; And When the condensation pressure is greater than the set pressure (α), the overload performance, characterized in that it comprises a control unit for stopping the operation of one of the first compressor 101 and the second compressor 102 for a predetermined time Air conditioner for improvement. The method of claim 1, When the high pressure switch 200 is detected that the condensation pressure (Pd) is greater than the set pressure (α), it is configured to generate an on (on) or off (off) signal to the control unit, the performance improvement during overload Air conditioner for cars. When it is detected that the condensation pressure Pd of the refrigerant passing through the outdoor heat exchanger 110 is greater than the set pressure α, one of the first compressor 101 and the second compressor 102 being operated is A first step of lowering the condensation pressure Pd by stopping; And And a second step of restarting the stopped compressor once the stop time of the compressor has passed the set time (β). The method of claim 3, wherein In the first step of stopping one of the two compressors, the stopped compressor is a compressor that has not been stopped in the previous step, the control method of the air conditioner for improving performance under overload.

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