KR20080110131A - Air conditioner and control method of the same - Google Patents

Abstract

An air conditioner and a control method thereof are provided to realize system stabilization in a short time and improve system responsibility according to various load conditions such as atmospheric temperature. A method for controlling an air conditioner includes the steps of obtaining at least any one data of the degree of suction superheat or supercool(S12), determining whether the obtained data is proper for normal control(S14), setting the target discharge temperature of a compressor higher than a calculated value therefore if so(S16), while setting the target discharge temperature lower than the calculated value in the other case(S18).

Description

Air conditioner and control method {Air conditioner and Control method of the same}

1 is a bird's eye view of an air conditioner according to the present invention.

2 is a view showing an air conditioner according to the present invention.

3 is a block diagram showing an air conditioner according to the present invention.

Figure 4 is a flow chart according to the main control method during the heating operation of the air conditioner according to the present invention.

<Explanation of symbols on main parts of the drawings>

2 ; Indoor heat exchanger 4; Indoor blower

6; Indoor electronic expansion valve 8; Indoor heat exchanger temperature sensor

10; Outdoor heat exchanger 12; Outdoor blower

14; Accumulators 15,16; compressor

17; Four-way valve 18; Outdoor electronic expansion valve

20; Outdoor heat exchanger temperature sensor

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 thereof in which the superheat control condition can be varied depending on the suction superheat and the discharge superheat when the compressor is running, at least during the heating operation. will be.

In general, an air conditioner is an air conditioning cycle consisting of a compressor, a condenser, an evaporator, and an expansion valve, which supplies air or hot air to a building or a room where the air conditioner is installed. Separated by.

The separation type and the integrated type are functionally the same, but the separation type installs an indoor heat exchanger (evaporator or condenser) in an indoor unit, and an outdoor heat exchanger (condenser or evaporator) and a compressor in an outdoor unit, and separates them from each other as refrigerant piping. The one-piece unit is an indoor heat exchanger, a compressor, an outdoor heat exchanger, and an expansion valve.

The integrated air conditioner includes a window type air conditioner installed directly by hanging a device on a window, and a duct type air conditioner connected to an intake duct and a discharge duct and installed outside the room. The separate type air conditioners include stand type air conditioners installed upright and wall-mounted air conditioners mounted on a wall.

In addition, the air conditioner may be classified into a cooling air conditioner that is used only for cooling, and a heat pump type air conditioner that may be used for both cooling and heating.

Recently, a multi-type air conditioner in which at least one outdoor unit and a plurality of indoor units are connected in series has been widely used.

Typically, such an air conditioner controls the intake overheating of the expansion valve at the start of the compressor to stabilize the system. When the system is stabilized, the air conditioner also controls the discharge overheating of the expansion valve.

However, since the air conditioner according to the prior art as described above controls the expansion valve unconditionally when the compressor is started, it sometimes takes excessive time to reach the normal operation of the system stable state depending on load variables such as outdoor temperature. There is a problem that performance improvement is required, and the emotional quality may be deteriorated due to the response delay.

Especially in the case of low temperature heating operation where the outdoor temperature is relatively slow in the compressor discharge temperature rise, the compressor discharge temperature rise is relatively slow compared to the suction superheat rise at the start of the compressor. The opening of the expansion valve is excessively small, resulting in a low pressure drop, which seriously delays system stabilization.

The present invention has been made in order to solve the above problems of the prior art, when the compressor is started, the expansion valve is also controlled to control the suction overheat, and then after changing the superheat control condition of the expansion valve according to the suction superheat and discharge superheat, It is an object of the present invention to provide an air conditioner and a control method thereof capable of quickly operating normally in response to various operating conditions as well as low temperature heating operation conditions.

In order to solve the above problems, the present invention includes an information obtaining step of acquiring at least one information of the suction superheat degree or subcool degree; A determination step of determining whether it is suitable for normal control based on the obtained information; As a result of the determination, if it is suitable for normal control, the target discharge temperature of the compressor is set higher than the calculated value for setting the target discharge temperature of the compressor, and if it is not suitable for normal control, the target discharge temperature of the compressor is controlled. Provided is a control method of an air conditioner, including a control step of controlling by setting lower than a calculated value for setting.

The information acquiring step may acquire both the suction superheat and the supercooling information.

In the determining step, if at least one of the suction superheat and the supercooling degree deviates from a reference value for determining the suitability of the normal control, it may be determined that it is not suitable for the normal control.

The control method of the air conditioner may be performed during a heating operation during the cooling / heating operation of the air conditioner.

The calculated value for setting the target discharge temperature of the compressor can be calculated as a function of the low pressure and high pressure of the compressor, and the suction superheat factor.

The present invention also includes a compressor, a condenser, an expansion valve, and an evaporator in which the refrigerant is circulated in turn; According to the suction superheat degree or the supercooling degree, there is provided an air conditioner having a control unit which controls by setting the target discharge temperature of the compressor higher or lower than the calculated value for setting the target discharge temperature of the compressor.

The present invention also includes an indoor heat exchanger, a compressor, an expansion valve, an outdoor heat exchanger, and a four-way valve for cooling and heating operation; In the case of heating operation, an air conditioner having a control unit for controlling by setting the target discharge temperature of the compressor higher or lower than the calculated value for setting the target discharge temperature of the compressor according to the suction superheat degree or the supercooling degree.

In order to obtain the suction superheat or supercooling information, a low pressure pressure sensing unit for detecting the suction pressure of the compressor and an indoor heat exchanger temperature sensor for detecting the evaporation temperature may be included.

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

1 is a bird's eye view of an air conditioner according to the present invention, FIG. 2 is a view showing an air conditioner according to the present invention, and FIG. 3 is a block diagram showing an air conditioner according to the present invention.

The air conditioner according to the present embodiment may be applied to various types of air conditioners. For convenience of description, a plurality of indoor units I installed in the interior of a building among the various types of air conditioners, and the indoor units I and It is configured to include an outdoor unit (M) (S1) (S2) and a control unit (not shown) for controlling the indoor unit (I) and the outdoor unit (M) (S1) (S2) connected through a refrigerant pipe (P). The present invention is a multi-type that is cooled or heated by using an air conditioning cycle, and the description is limited to the heat pump type.

Each indoor unit (I) is an indoor heat exchanger (2) in which the indoor air of the room where each indoor unit (I) is installed and a refrigerant exchange heat, and the indoor air in the room where each indoor unit (I) is installed, the indoor heat exchanger (2). An indoor blower (4) for blowing air in the air, and an indoor electromagnetic expansion valve (6), which is an expansion valve for reducing the refrigerant and controlling the flow rate of the refrigerant during the cooling operation.

The indoor heat exchanger (2) is an evaporator that allows the indoor air to be cooled while the liquid refrigerant is sucked during the cooling operation of the air conditioner and the sucked liquid refrigerant is evaporated by the indoor air in which the indoor unit (I) which requests the cooling operation is installed. The gaseous refrigerant is sucked during the heating operation of the air conditioner, and the sucked gaseous refrigerant is condensed by the indoor air in which the indoor unit I, which requested the heating operation, is installed.

The indoor heat exchanger 2 may be provided with an indoor heat exchanger temperature sensor 8 capable of sensing the temperature of the refrigerant passing through the indoor heat exchanger 2. The indoor heat exchanger temperature sensor 8 senses the evaporation temperature of the refrigerant evaporated in the indoor heat exchanger 2 when the indoor heat exchanger 2 acts as an evaporator during a cooling operation, and the indoor heat exchanger during a heating operation. Bar 2 serves as a condenser to sense the condensation temperature of the refrigerant condensed in the indoor heat exchanger (2).

The indoor blower 4 is rotated by the indoor motor unit 4a connected to the indoor motor unit 4a and the indoor motor unit 4a, which are controlled by the control unit 38 to generate power. It consists of the indoor fan 4b which produces a blowing force.

The plurality of outdoor units (M) (S1) and (S2) are the main outdoor unit (M) that is always operated regardless of the load of the indoor unit (I), and the sub outdoor unit selectively operated according to the load of the indoor unit (I) ( S1) (S2).

The main outdoor unit M and the sub outdoor unit S1 and S2 may include an outdoor heat exchanger 10 through which outdoor air and a refrigerant exchange heat, and an outdoor blower 12 that blows outdoor air to the outdoor heat exchanger 10. An accumulator 14 for extracting only the gas refrigerant, two compressors 15 and 16 for compressing the gas refrigerant extracted from the accumulator 14, a four-way valve 17 for switching the refrigerant flow, and a heating operation. It is configured to include an outdoor electromagnetic expansion valve 18, which is an expansion valve that is controlled according to the degree of superheating and reduces the refrigerant and regulates the flow rate of the refrigerant.

The outdoor heat exchanger 10 acts as a condenser to suck the gaseous refrigerant during the cooling operation of the air conditioner and condense the sucked gaseous refrigerant by the outdoor air, and the liquid refrigerant is sucked during the heating operation of the air conditioner. The sucked liquid refrigerant acts as an evaporator to allow the outdoor air to evaporate.

The outdoor heat exchanger 10 may be provided with an outdoor heat exchanger temperature sensor 20 capable of sensing the temperature of the refrigerant passing through the outdoor heat exchanger 10. The outdoor heat exchanger temperature sensor 20 senses the condensation temperature of the refrigerant condensed in the outdoor heat exchanger 10 when the outdoor heat exchanger 10 acts as a condenser during the cooling operation, and the outdoor heat exchanger during the heating operation. Bar 10 acts as an evaporator senses the evaporation temperature of the refrigerant evaporated in the outdoor heat exchanger 10.

The outdoor blower 12 is controlled by the control unit 38 to generate power, and is connected to the outdoor motor unit 12a and the outdoor motor unit 12a by the power of the outdoor motor unit 12a. It consists of an outdoor fan 12b that rotates and generates a blowing force.

One of the two compressors 15 and 16 of the main outdoor unit M may be an inverter compressor, and the other may be provided as a constant speed compressor.

The two compressors 15 and 16 of the sub outdoor units S1 and S2 may be provided as constant speed compressors.

The suction side and the discharge side of the compressor 15 and 16 are provided with a low pressure sensing unit 22 and a high pressure sensing unit 23 for sensing the suction / discharge pressure of the compressor 15 and 16, respectively.

The accumulator 14 is a common accumulator so as to be connected to two compressors 15 and 16 together for common use.

In addition, the main outdoor unit (M) and the sub outdoor unit (S1) (S2) and the oil separator (30) and capillary tube (32) installed on the suction side of the compressor (15) and (16), and the indoor heat exchanger during cooling operation A subcooling device 34 for cooling the refrigerant moved to (2) and a liquid injection device 36 for lowering the temperature of the compressors 15 and 16 are further included.

On the other hand, the refrigerant pipe (P) is provided with a dryer 38 for removing moisture in the refrigerant pipe (P).

Looking at the operation of the air conditioner according to the present invention configured as described above with reference to Figures 1 to 4 as follows. For reference, the flow of the refrigerant during the cooling operation of the air conditioner according to the present invention is the same as the arrow shown in FIG. 3.

When any one of the plurality of indoor units I requests a cooling operation, the indoor unit I and the outdoor units M, S1 and S2 which have requested the cooling operation are driven. The refrigerant is then compressed in the compressors (15) and (16), and the refrigerant compressed in the compressors (15) and (16) is a four-way valve (17), an outdoor heat exchanger (10), and an outdoor electromagnetic expansion valve (18). And, after passing through the indoor electromagnetic expansion valve (6) and the indoor heat exchanger (2) in turn, are circulated to the compressors (15) and (16) through the four-way valve (17). Of course, the refrigerant is circulated only to the indoor unit (I) and the outdoor unit (M) (S1) (S2) requesting the cooling operation. As described above, when the refrigerant is circulated along the refrigerant pipe P, the refrigerant deprives the indoor air heat of the room in which the indoor unit I is installed from the indoor heat exchanger 2, thereby providing a room in which the indoor unit I is installed. Is cooled.

At this time, the indoor electromagnetic expansion valve (6) is controlled according to the suction superheat degree or the discharge superheat degree. The outdoor electromagnetic expansion valve 18 is fully open so that refrigerant passes through the outdoor electromagnetic expansion valve 18 and does not expand.

And, look at the operation during the heating operation of the air conditioner according to the present invention configured as described above are as follows. For reference, the flow of the refrigerant during the heating operation of the air conditioner according to the present invention is opposite to the arrow shown in FIG. 3.

When any one of the plurality of indoor units I requests heating operation, the refrigerant compressed by the compressors 15 and 16 is a four-way valve 17, an indoor heat exchanger 2, and an indoor electromagnetic expansion valve ( 6), the outdoor electromagnetic expansion valve 18, and the outdoor heat exchanger 60 in turn, and then circulated to the compressors 15 and 16 through the four-way valve 17. Then, the refrigerant discharges heat from the indoor heat exchanger 2 to the indoor air of the room where the indoor unit I is installed, thereby heating the room where the indoor unit I is installed.

At this time, the indoor electromagnetic expansion valve (6) is passed through the indoor electromagnetic expansion valve (6), but is fully open (Full Open) so as not to expand. The outdoor electromagnetic expansion valve 18 is controlled according to the suction superheat degree or the discharge superheat degree.

In particular, the air conditioner according to the present invention also controls the overheating of the outdoor electromagnetic expansion valve 18 as follows in order to quickly stabilize the system at the initial operation, that is, when the compressors 15 and 16 are started.

Namely, when the heating operation is performed, the suction superheat degree or the subcool degree information is obtained. It is possible to obtain only the suction heating degree information, it is also possible to obtain only the subcooling information, and it is also possible to obtain both the suction superheating degree and the subcooling information. Hereinafter, the present invention will be limited to obtaining both the suction superheat degree and the subcooling information.

The suction superheat degree is a value obtained by subtracting the evaporation temperature from the suction temperature of the compressors (15) and (16), and the supercooling degree is a value obtained by subtracting the evaporation temperature from the discharge temperature of the compressors (15) and (16). Here, the suction temperature of the compressor (15) 16 may be sensed by a temperature sensor, and the temperature-pressure correlation from the suction pressure of the compressor (15) 16 sensed by the low pressure pressure sensing unit (22). It may be calculated according to the relationship. The evaporation temperature may be obtained by the outdoor heat exchanger temperature sensor 20.

When the suction superheat and supercooling information is obtained, the obtained suction superheat and supercooling degree are compared with a predetermined reference value suitable for normal control. That is, the comparing step compares the suction superheat degree with the reference value A of the suction superheat degree for the determination of the preset normal control, and compares the supercooling degree with the reference value B of the supercooling degree for the determination of the preset normal control. Compare. The reference values (A) and (B) for the determination of the preset normal control may be determined by the test values, respectively, so that a situation in which the error of the discharge superheat degree may be out of an allowable range can be recognized. In particular, when the heating operation is performed after being left at a low temperature for a long time, the discharge superheat degree at the start is considerably high, but the discharge piping temperature of the compressors 15 and 16 and the actual discharge of the compressors 15 and 16 are calculated. The error of temperature is so large that the discharge temperature rise of the compressor 15 and 16 is considerably slow, and the error of the discharge superheat degree is large. Therefore, the reference values (A) and (B) for the determination of the preset normal control may be determined by the test values, respectively, in consideration of such low temperature heating operation conditions. As an example, the reference value A of the suction superheat degree for determining the preset normal control may be set to 0 ± 2 ° C. to 20 ± 2 ° C. The reference value B of the subcooling degree for the determination of the preset normal control may be set to 5 ± 2 ° C. to 10 ± 2 ° C.

As a result of the comparison, if both the suction superheat and the supercooling degree do not exceed the reference value (A) (B) for the determination of the preset normal control, it is recognized as a situation suitable for the normal control, and is normally controlled. That is, in the normal control, the target discharge temperature of the compressor 15, 16 is set to the target discharge temperature of the compressor in consideration of the temperature loss while the refrigerant is discharged from the compressor 15 and 16 and flows toward the condenser. It is set higher than the calculation for. That is, the target discharge temperature equation of the compressor may be output in the following normal control.

Compressor target discharge temperature = Funtion (compressor low pressure, compressor high pressure, suction superheat) + normal control correction value.

Here, the normal control correction value may be set in consideration of the capacity of the air conditioner, the flow rate of the refrigerant, the type of refrigerant, etc., for example, may be 2 ± 0.5 ℃.

On the other hand, as a result of the comparison, if any one of the suction superheat and the supercooled temperature exceeds the reference value (A) (B) for the determination of the predetermined normal control, it is recognized as a special situation such as low temperature heating and the like, and complementary control do. That is, in the complementary control, the actual discharge superheat is high, but considering that the discharge temperature rise of the compressors 15 and 16 is considerably slow, the target discharge temperature of the compressors 15 and 16 is set to the target discharge temperature of the compressor. It is set lower than the calculation for. That is, the target discharge temperature equation of the compressor may be output during the following complementary control.

Compressor's target discharge temperature = complement (Compressor low pressure, compressor high pressure, suction superheat)-Complementary control correction value.

Here, the complementary control correction value may be set in consideration of the capacity of the air conditioner, the flow rate of the refrigerant, the type of refrigerant, etc., for example, may be 5 ± 0.5 ℃.

After the target discharge temperature of the compressor is set as described above, the opening degree value of the outdoor electromagnetic expansion valve 18 is set so that the discharge temperature of the compressor matches the target discharge temperature of the compressor.

On the other hand, after acquiring and comparing the suction superheat and supercooling information, the control step is repeatedly circulated while the air conditioner is heated. At this time, the repetition period may be set in units of a predetermined time, or may be set according to variation of information change of the suction superheat and the supercooling degree.

As described above, the air conditioner and the control method thereof according to the present invention are not limited to the above embodiments, and may be variously implemented within the technical scope to which the present invention belongs. That is, even in the cooling operation, the superheat control condition at the time of starting the compressor may be changed according to the suction superheat and the supercooling degree. In this case, the superheat control variation condition may be the same as or different from the above embodiment. In addition to the multi-type heat pump type, which is the above embodiment, a multi-type dedicated for cooling / heating is also possible, a single type for cooling / heating is also possible, and is applicable to a single type heat pump type.

According to the air conditioner and the control method according to the present invention as described above, the target discharge temperature of the compressor may be set higher or lower than the calculated value for setting the target discharge temperature of the compressor according to the comparison result of the suction superheat and the supercooling. This prevents excessive low pressure drop during heating and cooling operation, especially during heating operation, so that the system stability can be stabilized quickly and quickly in response to various load conditions such as outdoor temperature, thereby improving performance and improving the sensitivity quality related to system responsiveness. There is an advantage to this.

Claims (8)

An information acquiring step of acquiring information of at least one of suction superheat degree and subcool degree; A determination step of determining whether it is suitable for normal control based on the obtained information; As a result of the determination, if it is suitable for normal control, the target discharge temperature of the compressor is set higher than the calculated value for setting the target discharge temperature of the compressor, and if it is not suitable for normal control, the target discharge temperature of the compressor is controlled. The control method of the air conditioner comprising a control step of controlling by setting lower than the calculated value for the setting. The method according to claim 1, The information obtaining step is a control method of the air conditioner to obtain both the information of the suction superheat and supercooling degree. The method according to claim 2, The determining step is a control method of an air conditioner, if at least one of the suction superheat and the supercooling degree is out of the reference value for determining the suitability of the normal control, it is determined that it is not suitable for the normal control. The method according to any one of claims 1 to 3, The control method of the air conditioner is a control method of the air conditioner performed during the heating operation during the cooling / heating operation of the air conditioner. The method according to any one of claims 1 to 3, And a calculation value for setting a target discharge temperature of the compressor is calculated as a function of low pressure and high pressure of the compressor, and suction superheat factor. A compressor through which the refrigerant is circulated, a condenser, an expansion valve, and an evaporator; And a control unit which controls the target discharge temperature of the compressor by setting it higher or lower than a calculated value for setting the target discharge temperature of the compressor according to the suction superheat degree or the supercooling degree. An indoor heat exchanger, a compressor, an expansion valve, an outdoor heat exchanger, and a four-way valve for cooling and heating operation; In the case of heating operation, an air conditioner having a control unit which controls the target discharge temperature of the compressor by setting it higher or lower than a calculated value for setting the target discharge temperature of the compressor according to the suction superheat degree or the supercooling degree. The method according to claim 6 or 7, To obtain the suction superheat or subcooling information, a low pressure pressure sensing unit for detecting the suction pressure of the compressor, and an air conditioner temperature sensor for sensing the evaporation temperature.

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