KR20070077639A - Multi air-conditioner and its control method - Google Patents

Abstract

A multi air conditioner and a controlling method thereof are provided to improve indoor heating performance by raising a pipe discharge temperature more than a pipe suction temperature of an indoor unit. A multi air conditioner includes an outdoor unit(100), an indoor unit(200), a detecting unit(110), and a controlling unit(120). The outdoor unit has an outdoor heat exchanger, a compressor, and an electronic expanding valve. The detecting unit detects the temperature of the outdoor heat exchanger, the suction and discharge temperatures of the compressor, and the condensation temperature of the indoor unit. The controlling unit determines the degree of suction superheat by calculating the difference between the suction temperature of the compressor measured in the detecting unit and the temperature of the outdoor heat exchanger, and controls the electronic expanding valve to increase the degree of suction superheat by a predetermined temperature according to the condensation temperature of the indoor unit.

Description

Multi air conditioner and its control method

1 is a perspective view showing the configuration of a multi-air conditioner according to the prior art,

2 is a block diagram showing an outdoor unit of the multi-air conditioner according to the prior art,

3 is a perspective view showing the configuration of a multi-air conditioner according to the present invention;

4 is a block diagram illustrating an outdoor unit of the multi-air conditioner according to the present invention;

5 is a block diagram showing the configuration of a multi air conditioner according to the present invention;

6 is a flowchart illustrating a control method of a multi air conditioner according to the present invention.

<Explanation of symbols on main parts of the drawings>

100: outdoor unit 110: detector

120: control unit 121: temperature determination unit

122: electronic expansion valve control unit 200: indoor unit

The present invention relates to a multi-air conditioner and a control method thereof. In particular, the suction superheat degree is determined by the difference between the suction temperature of the compressor and the temperature of the outdoor heat exchanger during the heating operation, and the suction superheat degree according to the condensation temperature of the indoor unit. It relates to a multi-air conditioner and a control method for controlling the electronic expansion valve so as to rise above a predetermined temperature.

In general, an air conditioner has been mainly used as a cooling device that discharges cold air generated through heat exchange with ambient air due to evaporation of a refrigerant to a room using a fan by compressing, evaporating, and condensing a predetermined refrigerant. In a building having two independent indoor spaces, an indoor unit is installed in each independent indoor space, and a multi-type air conditioner including one indoor unit connected thereto is widely used.

In addition, in recent years, by using the compression, evaporation and condensation cycle of the refrigerant inversely, the hot air generated through heat exchange between the refrigerant and the caution air due to the condensation of the refrigerant is discharged into the room by using a fan, which has a heating and cooling function. As functions become widespread, air conditioners are being used as devices to control the indoor temperature of the home throughout the four seasons.

1 is a perspective view showing a configuration of a multi-air conditioner according to the prior art, Figure 2 is a block diagram showing an outdoor unit of the multi-air conditioner according to the prior art.

As shown in FIG. 1, a multi-air conditioner according to the related art is provided with a plurality of outdoor units 1, 2, 3 and a plurality of indoor units connected through a refrigerant pipe, and the outdoor units 1, 2, 3. At least one is driven corresponding to the load of the indoor unit.

Here, the outdoor unit (1) is an accumulator (4) for extracting only the gas refrigerant from the refrigerant supplied from the indoor unit, a compressor (5) (6) for receiving and compressing the gas refrigerant extracted from the accumulator (4), A four-way valve 7 connected to the compressors 5 and 6 to select a flow path of the compressed refrigerant, and an outdoor heat exchanger 8 for heat-exchanging the refrigerant supplied from the four-way valve 7 with the outdoor air. It is composed.

Here, the compressor (5) (6) is composed of an inverter compressor (5) capable of varying the discharge capacity of the refrigerant and a constant speed compressor (6) for discharging only a predetermined amount of refrigerant, the remaining outdoor unit (2) 3, unlike the outdoor unit 1, two constant speed compressors 6 are installed.

In particular, the inverter compressor 5 is responsible for 70% of the total refrigerant compression capacity of the outdoor unit 1, and the constant speed compressor 6 is responsible for the remaining 30%.

In addition, the indoor unit is connected to the outdoor unit 1 through a refrigerant pipe, an indoor heat exchanger (not shown) for condensing the refrigerant discharged from each of the compressors 5 and 6, and heat radiated from the indoor heat exchanger. It is configured to include an indoor fan (not shown) to discharge to the room.

Here, the operation sequence of the outdoor unit in the conventional multi-type air conditioner is as follows.

First, when any one of the plurality of indoor units is driven, the first outdoor unit 1 equipped with the inverter compressor 5 is driven, and when the cooling / heating capacity required by the indoor unit is increased, the remaining compressors correspondingly. (6) or the outdoor unit (2) (3) is driven.

That is, the inverter compressor 5 is configured to be driven first regardless of which indoor unit is driven to correspond to the cooling / heating load of the indoor unit.

When the air / heating load required by the indoor unit exceeds the inverter compressor 5, the constant speed compressor 6 in the constant speed compressor 6 of the first outdoor unit 1 or the remaining outdoor units 2 and 3 is used. ) Is driven to replace the compression capacity of the inverter compressor (5), the inverter compressor (5) is down to the lowest compression capacity, and the inverter compressor (5) again when the cooling / heating capacity of the indoor unit is further increased Increases the compression capacity again in response to the cooling / heating capacity.

On the other hand, the multi-air conditioner is performed in the cooling operation or heating operation as the circulating direction of the refrigerant is reversed as the four-way valve (7) is switched, the refrigerant extruded from the compressor (5) (6) in the heating operation It flows through a four-way valve (7), an indoor heat exchanger, an expansion valve (not shown), an outdoor heat exchanger (8), and a compressor (5) and (6), and heat is transferred to the room while the refrigerant is condensed in the indoor heat exchanger. Emanates. As such, in contrast to the cooling operation of the air conditioner, the outdoor unit 1 serves as an evaporator and the indoor unit serves as a condenser during heating operation.

However, such a conventional multi air conditioner has a single pipe multi in a heating operation.

The flow rate of the refrigerant is controlled by the expansion valve. At this time, if the condensation temperature of the indoor unit is higher than or equal to the discharge temperature of the compressor, the refrigerant flows into the compressor, causing a liquid compression phenomenon. There is a problem that the service life and reliability of the compressor are significantly lowered.

The present invention has been made to solve the above-mentioned problems of the prior art, the object is to increase the suction superheat according to the temperature difference between the suction temperature of the compressor and the temperature of the outdoor heat exchanger during heating operation to a predetermined temperature higher than the condensation temperature of the indoor unit. The present invention provides a multi-air conditioner and a method of controlling the same, by controlling an electromagnetic expansion valve to prevent a liquid compression phenomenon and to improve the reliability and stability of the compressor.

Multi air conditioner according to the present invention for solving the above problems is an outdoor heat exchanger, an outdoor unit having a compressor and an electronic expansion valve, and a multi air conditioner connected to an indoor unit, the outdoor heat exchanger temperature, the suction and discharge of the compressor A sensing unit for measuring a temperature and a condensation temperature of the indoor unit, and a suction superheat degree is determined by calculating a difference between the suction temperature of the compressor and the temperature of the outdoor heat exchanger measured by the sensing unit, and the suction superheat degree according to the condensation temperature of the indoor unit. It characterized in that it comprises a control unit for controlling the electronic expansion valve to rise above a predetermined temperature.

In addition, the control method of the multi-air conditioner includes a first step of detecting the outdoor heat exchanger, the suction and discharge temperatures of the compressor, the condensation temperature of the indoor unit, and comparing the respective detected temperatures to calculate the intake superheat and the condensation of the indoor unit. And a third step of controlling the electronic expansion valve such that the suction superheat is raised above a predetermined temperature according to the determined condensation temperature.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 3 is a perspective view showing the configuration of a multi air conditioner according to the present invention, Figure 4 is a block diagram showing an outdoor unit of the multi air conditioner according to the present invention.

As shown in FIG. 1 or 2, the multi-air conditioner according to the present invention includes a plurality of indoor units 11, 12, 13, 14, and indoor units 11, 12 ( 13 and 14, which are connected to the outdoor units 21, 22, and 23, wherein the indoor units 11, 12, 13, 14, and the outdoor units 21, 22, 23 are refrigerants. Is connected through the pipe 30, 40, the outdoor unit 21, 22, 23 is driven by the request of at least one of the indoor unit 11, 12, 13, 14, As the air / heating capacity required by the indoor units 11, 12, 13 and 14 increases, the number of operation of the outdoor units 21, 22 and 23 and the compressors installed in the outdoor units 21 and 22 are increased. The number of operations is increased.

Here, the indoor units 11, 12, 13 and 14 are indoor heat exchangers 51 for exchanging refrigerant and indoor air, and indoor blowers installed near the indoor heat exchangers 51 to circulate indoor air. 52 and an indoor expansion valve 54 for expanding the refrigerant flowing to the indoor heat exchanger 51 during cooling.

In addition, the outdoor units 21, 22, and 23 are composed of first, second, and third outdoor units 21, 22, and 23, as shown in FIG. 2, and only the gas refrigerant is supplied from the indoor unit. The accumulator 61 to be extracted, the compressors 62, 63 and 67 which receive and compress the gas refrigerant extracted from the accumulator 61, and the compressor 62 and 63 are connected to each other. It comprises a four-way valve (65) for selecting a flow path, and an outdoor heat exchanger (70) for exchanging heat between the refrigerant supplied from the four-way valve (65) and outdoor air.

Here, the first outdoor unit 21 is provided with an inverter compressor 62 and a constant speed compressor 63, and the second and third outdoor units 22 and 23 are provided with only a plurality of constant speed compressors 67, and the inverter The compressor 62 is a compressor capable of varying the compression capacity of the refrigerant, and the constant speed compressors 63 and 67 are compressors having a constant compression capacity of the refrigerant.

In addition, the inverter compressor 62 is responsible for 70% of the compression capacity of the first outdoor unit 21, the constant speed compressor 63 installed in the first outdoor unit 21 is responsible for the remaining 30%, the remaining outdoor unit ( The constant speed compressors 67 of 22 and 23 each bear a compression capacity of 50%.

On the other hand, an oil separator 64 is installed in a pipe connecting the compressors 62 and 63 and the four-way valve 65, and the oil separator 64 is provided at the suction side of the compressors 62 and 63. Connected.

In addition, a pressure sensor 107 is installed between the oil separator 64 and the compressors 62, 63, 67 to sense the pressure of the refrigerant discharged from the compressors 62, 63, 67. .

In particular, the oil separator 64 separates oil from the refrigerant discharged from the compressors 62 and 63 and supplies the separated oil to the compressors 62 and 63 to supply the compressors 62 and 63. Maintain an appropriate amount of oil inside. And the suction side pipe of the oil separator 64 and the compressor 62, 63 is connected through a capillary tube 66, the oil is moved through the capillary tube 66.

In addition, the refrigerant pipe (30) for guiding the refrigerant discharged from the outdoor heat exchanger (70) to the indoor heat exchanger (51) has an electronic expansion valve (lev, 74) for expanding the refrigerant upon heating, and the indoor during cooling. Sub-cooling device 80 for cooling the refrigerant moved to the heat exchanger 51, and a liquid injection device 90 for lowering the temperature of the compressor (62, 63) is provided.

Here, the outdoor electromagnetic expansion valve (74) is full open during cooling to pass through the refrigerant condensed in the outdoor heat exchanger without expanding, but when heated to open a predetermined size to condense the refrigerant condensed in the indoor heat exchanger (51). Before entering the outdoor heat exchanger 70 is expanded to a liquid in a spray state.

On the other hand, the refrigerant pipe (30 ") is provided with a dryer (110) for removing moisture in the refrigerant pipe (30"), the refrigerant passing through the dryer 110 is a by-pass in the refrigerant pipe (30 ") Passed and flow to the indoor heat exchanger (51) side.

5 is a block diagram showing the configuration of a multi air conditioner according to the present invention, Figure 6 is a flow chart showing a control method of a multi air conditioner according to the present invention.

As shown in FIG. 5, the multi-air conditioner according to the present invention is configured by connecting an outdoor unit 100 having an outdoor heat exchanger, a compressor, and an electronic expansion valve, and an indoor unit 200.

The outdoor unit 100 includes a detector 110 for measuring the outdoor heat exchanger temperature, the suction and discharge temperatures of the compressor, and the pipe suction / discharge temperature of the indoor unit, the suction temperature of the compressor measured by the detector 110, and And calculating a temperature difference of the outdoor heat exchanger to determine the suction superheat degree, and controlling the electronic expansion valve so that the suction superheat degree rises above a predetermined temperature according to the measured condensation temperature of the indoor unit. .

The sensing unit 110 has a plurality of sensors for measuring the respective temperatures are provided on the outdoor heat exchanger, the suction side, the discharge side, the indoor unit pipe suction side / pipe discharge side of each of the outdoor heat exchanger temperature, the compressor suction / Measure the discharge temperature and the suction / discharge temperature of the indoor unit piping.

The control unit 120 calculates the respective temperatures measured by the detection unit 110 to determine the intake superheat degree and the condensation temperature of the indoor unit, and the determined condensation temperature of the indoor unit. It is configured to include an electronic expansion valve control unit for controlling the electronic expansion valve to increase the suction superheat according to a predetermined temperature.

The temperature determining unit 120 compares and calculates each temperature measured by the detecting unit 110 to determine the suction superheat degree and the condensation temperature of the indoor unit.

Here, the temperature determining unit 120 calculates the difference between the measured suction temperature of the compressor and the temperature of the outdoor heat exchanger, and determines the difference between the calculated temperatures as the suction superheat, and determines the pipe suction temperature and the pipe discharge temperature of the indoor unit. The average temperature is calculated to determine the calculated average temperature as the condensation temperature of the indoor unit.

The electronic expansion valve adjusting unit 122 controls the opening of the electronic expansion valve so that the suction superheat rises approximately 15 ° C. or more above the condensation temperature of the indoor unit determined by the temperature determining unit 120.

Here, the electronic expansion valve control unit 122 controls the electronic expansion valve to increase the suction superheat degree by approximately 15 ° C. or more than the condensation temperature of the indoor unit, wherein the suction superheat degree is lower than the condensation temperature of the indoor unit or In the same case, since the refrigerant of the compressor flows in to generate a liquid compression phenomenon, the electronic expansion valve is controlled to raise the suction superheat degree by approximately 15 ° C. or more above the condensation temperature of the indoor unit to prevent the liquid compression phenomenon.

In addition, the electronic expansion valve adjusting unit 122 adjusts the electronic expansion valve to maintain the pipe discharge temperature of the indoor unit approximately 35 ℃ or more.

For example, the electronic expansion valve control unit 122 controls the electronic expansion valve in order to improve the indoor heating performance because the flow rate of the refrigerant in the interior is reduced when the pipe suction temperature of the indoor unit is higher than the pipe discharge temperature. Open by 2 pulses per control to maintain approximately 35 ℃ or more.

As shown in FIG. 6, first, a plurality of sensors are provided to measure temperatures of an outdoor heat exchanger, a compressor, and an indoor unit, respectively.

For example, the outdoor heat exchanger, the suction side / discharge side of the compressor, the pipe suction side / discharge side of the indoor unit is provided with a plurality of sensors, respectively, the outdoor heat exchanger temperature, discharge / suction temperature of the compressor, pipe suction / of the indoor unit Measure each discharge temperature.

Comparing and calculating the respective measured temperatures to determine the intake superheat degree and the condensation temperature of the indoor unit. (S2, S3)

Here, the calculated difference between the suction temperature of the compressor and the temperature difference of the outdoor heat exchanger is calculated, and the determined temperature difference is determined as the suction superheat, and the average temperature of the measured pipe suction temperature and pipe discharge temperature of the indoor unit is calculated. The average temperature calculated is determined as the condensation temperature of the indoor unit.

At this time, the electronic expansion valve is controlled to increase the suction superheat degree by a predetermined temperature or more than the determined condensation temperature of the indoor unit. (S4)

For example, when the average temperature of the pipe suction temperature and the pipe discharge temperature of the indoor unit is equal to or higher than the suction superheat degree, a liquid compression phenomenon occurs in which the refrigerant of the compressor flows. By adjusting the expansion valve to control the suction superheat so that the condensation temperature of the indoor unit rises approximately 15 ℃ or more.

At this time, when controlling the electronic expansion valve to increase the suction superheat degree, the electronic expansion valve is controlled so that the pipe discharge temperature of the indoor unit is maintained above a predetermined temperature.

That is, since the indoor discharge performance can be improved by increasing the pipe discharge temperature than the pipe suction temperature of the indoor unit, the electronic expansion valve is controlled to maintain the indoor pipe discharge temperature approximately 35 ° C. or more.

As described above, the multi-air conditioner and the control method according to the present invention have been described with reference to the illustrated drawings, but the present invention is not limited by the embodiments and drawings disclosed herein, and the technical spirit of the present invention is protected. The application is possible by those skilled in the art within the scope.

The multi-air conditioner and the control method according to the present invention configured as described above calculates the difference between the suction temperature of the compressor and the temperature difference between the outdoor heat exchanger during the heating operation, and determines the suction superheat degree, and determines the suction superheat degree of the indoor unit. By controlling the electronic bulge so as to rise above a predetermined temperature than the condensation temperature, the liquid compression phenomenon that the refrigerant is introduced into the compressor is prevented, thereby improving the reliability and stability of the compressor and improving the efficient indoor heating performance.

Claims (7)

In the outdoor unit equipped with an outdoor heat exchanger, a compressor and an electronic expansion valve, and a multi air conditioner connected to an indoor unit, A detector for measuring the outdoor heat exchanger temperature, the suction and discharge temperatures of the compressor, and the condensation temperature of the indoor unit; The controller determines the suction superheat degree by calculating the difference between the suction temperature of the compressor and the temperature of the outdoor heat exchanger measured by the sensing unit, and controls the electronic expansion valve to increase the suction superheat degree by a predetermined temperature or more according to the condensation temperature of the indoor unit. Multi air conditioner characterized in that comprises a. The method according to claim 1, The control unit calculates the respective temperatures measured by the sensing unit to determine the suction superheat degree and the condensation temperature of the indoor unit, and to increase the suction superheat degree above a predetermined temperature according to the determined condensation temperature of the indoor unit. Multi air conditioner comprising an electronic expansion valve control unit for controlling the electronic expansion valve. The method according to claim 2, The predetermined temperature is approximately 15 ℃ multi air conditioner. The method according to claim 2, The condensation temperature of the indoor unit is a multi-air conditioner, characterized in that calculated by the average temperature of the indoor pipe suction temperature and the indoor pipe discharge temperature of the indoor unit. A first step of sensing the intake and discharge temperatures of the outdoor heat exchanger, the compressor, and the condensation temperature of the indoor unit; A second step of comparing the detected respective temperatures to determine the suction superheat degree and the condensation temperature of the indoor unit; And a third step of controlling the electronic expansion valve such that the suction superheat is raised above a predetermined temperature according to the determined condensation temperature. The method according to claim 5, In the second step, the suction temperature of the detected compressor and the temperature difference of the outdoor heat exchanger are calculated to determine the suction superheat degree, and the average temperature of the indoor pipe suction temperature and the indoor pipe discharge temperature of the indoor unit is calculated. The control method of a multi air conditioner, characterized in that for determining the condensation temperature. The method according to claim 5, The third step is a control method of the multi-air conditioner, characterized in that the intake superheat is maintained at about 15 ℃ or more than the condensation temperature of the indoor unit.

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