KR101442108B1 - Air conditioner and the control method of the same - Google Patents

Abstract

The air conditioner and its control method according to the present invention compares discharge temperatures of a plurality of compressors and selectively controls opening and closing of hot gas valves disposed around the plurality of compressors, The deviation can be reduced and the flow rate can be evenly distributed, and the overheating phenomenon of the compressor can be prevented, and the reliability can be improved.

Air conditioner, multi, compressor, discharge temperature, flow rate, hot gas, reliability

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner,

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 control method thereof that can reduce a discharge temperature deviation of a plurality of compressors, will be.

Generally, an air conditioner performs a process of compressing, condensing, expanding, and evaporating a refrigerant, thereby cooling or heating the indoor space.

The multi-type air conditioner includes at least one outdoor unit and a plurality of indoor units, and the indoor unit and the outdoor unit are connected through a refrigerant pipe.

The outdoor unit includes an accumulator for extracting only the gas refrigerant from the refrigerant supplied from the indoor unit, a compressor for receiving and compressing the gas refrigerant extracted from the accumulator, and an outdoor unit connected to the compressor for selecting the flow path of the refrigerant compressed in accordance with the cooling / A valve, and an outdoor heat exchanger for exchanging the circulated refrigerant with outdoor air.

The indoor unit includes an expansion valve and an indoor heat exchanger for exchanging heat between the circulated refrigerant and indoor air.

However, in the conventional multi-type air conditioner, a difference in the distribution of refrigerant flow rates in a plurality of outdoor periods is generated, and liquid compression may occur in a compressor of an outdoor unit in which a refrigerant flow rate is excessively distributed among the plurality of outdoor units. There is a problem that the discharge temperature of the refrigerant is excessively increased in the compressor of the outdoor unit to be distributed. As a result, there is a problem that the compressor is broken and the reliability of the product is lowered.

An object of the present invention is to provide a multi-type air conditioner capable of preventing damage to a compressor and improving reliability.

The present invention provides a compressor comprising: a plurality of compressors; A plurality of hot gas pipes arranged to bypass a part of the refrigerant discharged from each of the plurality of compressors to the suction side of each of the compressors; A plurality of hot gas valves respectively disposed in the plurality of hot gas pipes; And controls opening and closing of the plurality of hot gas valves differently when the difference between the highest discharge temperature and the lowest discharge temperature among the discharge temperatures of the plurality of compressors is equal to or higher than a first set temperature And an air conditioner including a control unit.

The present invention also provides a compressor comprising: a compressor; a hot gas piping arranged to bypass a part of the refrigerant discharged from the compressor to a suction side of the compressor; a plurality of outdoor units each including a hot gas valve and; Wherein when the difference between the highest discharge temperature and the lowest discharge temperature among the compressor discharge temperatures of the plurality of outdoor units is equal to or higher than a first set temperature, opening / closing of the hot gas valves of the plurality of outdoor units And an air conditioner including a control unit that controls the air conditioner in a different manner.

According to another aspect of the present invention, there is provided a method for controlling an outdoor unit, comprising the steps of: comparing respective compressor discharge temperatures of a plurality of outdoor units; comparing, when a difference between the compressor discharge temperatures is equal to or higher than a first predetermined temperature, And opening the hot gas valve of the air conditioner.

In the present invention, among the plurality of outdoor units, the hot gas valves of the outdoor units excluding the outdoor units having the lowest discharge temperature of the compressor are shielded.

In the present invention, it is preferable that the method further comprises: comparing the compressor discharge temperatures of the plurality of outdoor units with each other while the hot gas valve of the outdoor unit having the lowest compressor discharge temperature is opened; And if it is lower than the predetermined temperature, shielding the hot gas valve of the outdoor unit having the lowest compressor discharge temperature.

The air conditioner and its control method according to the present invention compares discharge temperatures of a plurality of compressors and selectively controls opening and closing of hot gas valves disposed around the plurality of compressors, The deviation can be reduced and the flow rate can be evenly distributed, and the overheating phenomenon of the compressor can be prevented, and the reliability can be improved.

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

1 is a configuration diagram illustrating a multi-type air conditioner according to an embodiment of the present invention.

Referring to FIG. 1, the multi-type air conditioner includes a plurality of indoor units I installed in the room and a plurality of outdoor units connected to the plurality of indoor units I. The plurality of indoor units (I) and the plurality of outdoor units are connected through refrigerant pipes (10) and (11). In the present embodiment, it is assumed that the plurality of outdoor units are two first and second outdoor units 20 and 40. However, the present invention is not limited to this, and it is of course possible that the number of the outdoor units is two or more. The first and second outdoor units 20 and 40 are driven by a request of at least one of the plurality of indoor units I so that as the cooling / heating capacity required by the plurality of indoor units I increases, The number of operation of the 1,2 outdoor units 20 and 40 can be adjusted.

The plurality of indoor units I include an indoor heat exchanger 12 for exchanging heat between the refrigerant and the indoor air and an indoor expansion valve 13 for expanding the refrigerant flowing into the indoor heat exchanger 12 during the cooling operation do.

The first outdoor unit 20 includes a first accumulator 21 for extracting only gas refrigerant from the refrigerant supplied from the indoor unit I and a second accumulator 21 for receiving and compressing the gas refrigerant extracted from the first accumulator 21, A first four-way valve (23) connected to the first compressor (22) to select a flow path of the compressed refrigerant; a second four-way valve (23) The first outdoor heat exchanger (24). A first compressor discharge temperature sensor 25 for measuring the discharge temperature of the refrigerant discharged from the first compressor 22 is installed in the discharge side refrigerant pipe of the first compressor 22.

The first outdoor unit 20 further includes a first hot gas pipe 26 connecting the discharge side refrigerant pipe of the first compressor 22 and the suction side refrigerant pipe of the first accumulator 21. The first hot gas piping 26 is provided with a first capillary tube 27 and a first hot gas valve 28. The first hot gas valve 28 interrupts the refrigerant flow to the first hot gas piping 26.

A first oil separator 29 is installed in a pipe connecting the first compressor 22 and the first four-way valve 23 and the first oil separator 29 is connected to a suction pipe . The first oil separator 29 separates the oil from the refrigerant discharged from the first compressor 22 and supplies the separated oil to the first compressor 22, Maintain proper amount of oil.

The first outdoor unit 20 includes a first outdoor expansion valve 30 for expanding a refrigerant during heating, a second outdoor expansion valve 30 for introducing the refrigerant to the indoor heat exchanger 12, , And a first supercooling device (31) for cooling the refrigerant moving to the indoor heat exchanger (12) during cooling.

Like the first outdoor unit 20, the second outdoor unit 40 includes a second accumulator 41, a second compressor 42, a second four-way valve 43, a second outdoor heat exchanger (44), a second outdoor expansion valve (50), and a second supercooling device (51).

A second compressor discharge temperature sensor 45 for measuring the discharge temperature of the refrigerant discharged from the second compressor 42 is installed in the discharge side refrigerant pipe of the second compressor 42.

The discharge side refrigerant pipe of the second compressor (42) and the suction side refrigerant pipe of the second accumulator (41) are connected by a second hot gas pipe (46). A second capillary tube 47 and a second hot gas valve 48 are installed in the second hot gas piping 46.

A second oil separator 49 is installed in a pipe connecting the second compressor 42 and the second four-way valve 43.

2 is a block diagram schematically showing the configuration of the multi-type air conditioner shown in Fig.

Referring to FIG. 2, the multi-type air conditioner controls overall operation and compares sensed values of the first compressor discharge temperature sensor 25 and the second compressor discharge temperature sensor 45, And a control unit 60 for controlling the 1,2 hot gas valve 28 (48).

Hereinafter, a control method of the multi-type air conditioner according to the embodiment of the present invention will be described with reference to FIG.

That is, FIG. 3 is a flowchart showing the control method of the multi-type air conditioner shown in FIG.

When the multi-type air conditioner is turned on and cooling or heating operation is started, the first and second compressors 22 and 42 are operated (S1)

When the first and second compressors 22 and 42 are operated, the first compressor discharge temperature sensor 25 senses the discharge temperature of the refrigerant discharged from the first compressor 22, The temperature sensor 45 detects the discharge temperature of the refrigerant discharged from the second compressor 42. (S2)

The control unit 60 compares the first discharge temperature T1 sensed by the first compressor discharge temperature sensor 25 and the second discharge temperature T2 sensed by the second compressor discharge temperature sensor 45 do. That is, the difference between the first discharge temperature T1 and the second discharge temperature T2 is compared with the preset first set temperature T3 in the controller 60. (S3)

If the difference between the first discharge temperature T1 and the second discharge temperature T2 is larger than the first set temperature T3, the discharge temperature difference of the first and second compressors 22 and 42 becomes excessive . That is, if the first discharge temperature T1 is higher than the second discharge temperature T2, the refrigerant flow rate of the first outdoor unit 20 is less than that of the second outdoor unit 40, It is possible to determine that the first discharge temperature T 1 of the first discharge port 22 has risen excessively. Also, the refrigerant flow rate of the second outdoor unit (40) is excessively distributed to the first outdoor unit (20), and liquid compression may occur in the second compressor (42).

Therefore, if the difference between the first discharge temperature T1 and the second discharge temperature T2 is larger than the first set temperature T3, the control unit 60 opens the hot gas valve on the outdoor unit side, . That is, when the first discharge temperature T1 is higher than the second discharge temperature T2, the controller 60 controls the second hot gas valve 48 of the second outdoor unit 40 Open. Then, the first hot gas valve 28 of the first outdoor unit 20 is shielded. (S5)

When the second hot gas valve (48) is opened, the high-temperature and high-pressure refrigerant discharged from the second compressor (42) vaporizes the refrigerant on the suction side of the second accumulator (41). Therefore, the liquid compression phenomenon that may be generated in the second compressor (42) having a relatively low discharge temperature can be prevented. In addition, when the second hot gas valve 48 is opened, refrigerant flows to the first outdoor unit 20, thereby improving the flow rate distribution of the entire cycle and reducing the first discharge temperature T1 do.

While the second hot gas valve 48 is opened, the discharge temperature of the first and second compressors 22 and 42 is continuously detected. If the difference between the first discharge temperature T1 and the second discharge temperature T2 is smaller than the second preset temperature T4 set in the controller 60 at step S6, 48). (S7) Here, the second set temperature T4 is set to be smaller than the first set temperature T3.

If the difference between the first discharge temperature T1 and the second discharge temperature T2 is greater than the first set temperature T3 and the second discharge temperature T2 is greater than the first discharge temperature T1, The control unit 60 opens the first hot gas valve 28 of the first outdoor unit 20. In this case, Then, the second hot gas valve 48 is shielded (S8)

When the first hot gas valve 28 is opened, the high-temperature, high-pressure refrigerant discharged from the first compressor 22 flows into the suction side of the first accumulator 21 and the suction side of the first accumulator 21 The refrigerant is vaporized. Therefore, the liquid compression phenomenon that may be generated in the first compressor 22 having a relatively low discharge temperature can be prevented. In addition, when the first hot gas valve 28 is opened, the refrigerant flows to the second outdoor unit 40, thereby improving the flow rate distribution of the entire cycle and reducing the second discharge temperature T2 do.

And continuously senses the discharge temperature of the first and second compressors 22 and 42 while the first hot gas valve 28 is opened. Thereafter, when the difference between the first discharge temperature T1 and the second discharge temperature T2 becomes smaller than the second set temperature T4 (S9), the first hot gas valve 28 is shielded. S10)

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

1 is a configuration diagram illustrating a multi-type air conditioner according to an embodiment of the present invention.

2 is a block diagram schematically showing the configuration of the multi-type air conditioner shown in Fig.

Fig. 3 is a flowchart showing the control method of the multi-type air conditioner shown in Fig. 1. Fig.

BRIEF DESCRIPTION OF THE DRAWINGS Fig.

20: first outdoor unit 22: first compressor

25: first compressor discharge temperature sensor 26: first hot gas piping

28: first hot gas valve 40: second outdoor unit

42: second compressor 45: second compressor discharge temperature sensor

48: second hot gas valve 60:

Claims (5)

A plurality of compressors; A plurality of hot gas pipes arranged to bypass a part of the refrigerant discharged from each of the plurality of compressors to the suction side of each of the compressors; A plurality of hot gas valves respectively disposed in the plurality of hot gas pipes; And controls opening and closing of the plurality of hot gas valves differently when the difference between the highest discharge temperature and the lowest discharge temperature among the discharge temperatures of the plurality of compressors is equal to or higher than a first set temperature And an air conditioner. A plurality of outdoor units each including a hot gas piping arranged to bypass a part of the refrigerant discharged from the compressor to a suction side of the compressor, and hot gas valves respectively disposed in the hot gas piping; Wherein when the difference between the highest discharge temperature and the lowest discharge temperature among the compressor discharge temperatures of the plurality of outdoor units is equal to or higher than a first set temperature, opening / closing of the hot gas valves of the plurality of outdoor units Wherein the air conditioner includes a control unit that controls the air conditioner. Comparing respective compressor discharge temperatures of a plurality of outdoor units with each other; And opening the hot gas valve of the outdoor unit having the lowest compressor discharge temperature among the plurality of outdoor units when the difference in the compressor discharge temperature is equal to or higher than a preset first set temperature. The method of claim 3, Wherein the hot gas valve of the outdoor unit other than the outdoor unit having the lowest discharge temperature of the compressor among the plurality of outdoor units is shielded. The method of claim 3, Comparing the compressor discharge temperatures of the plurality of outdoor units with each other while the hot gas valve of the outdoor unit having the lowest compressor discharge temperature is opened; Further comprising the step of shielding the hot gas valve of the outdoor unit having the lowest compressor discharge temperature if the difference in the compressor discharge temperature is less than a preset second set temperature.

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