KR20080038511A - Multi-type air conditioner - Google Patents

Abstract

A multi-type air conditioner is provided to prevent generation of cycle hunting in a compressor by preventing superheating of the compressor by super cooling refrigerant while passing through a super cooler, thereby stabilizing a system and improving heating efficiency. An outdoor unit of a multi-type air conditioner includes a super cooling valve(152) installed at a super cooler(150) for controlling refrigerant flow. A refrigerant ejector ejects refrigerant to a compressor compressing the refrigerant to prevent super heating of the compressor. In case of heating operation, the super cooling valve, the refrigerant ejector, and the compressor are simultaneously or selectively controlled to maintain a temperature of refrigerant discharged from the compressor under the set temperature.

Description

Multi-type air conditioner

1 is a state diagram showing an installation state of a multi-type air conditioner employing a preferred embodiment according to the present invention.

Figure 2 is a block diagram showing the internal configuration of a multi-type air conditioner employing a preferred embodiment of the present invention.

Figure 3 is a block diagram showing the internal configuration of a multi-type air conditioner outdoor unit employing a preferred embodiment of the present invention.

Figure 4 is a partially enlarged view showing a part of a multi-type air conditioner outdoor unit employing a preferred embodiment according to the present invention.

Explanation of symbols on the main parts of the drawings

100. Outdoor unit 110. Constant speed compressor

110 '. Inverter compressor 111. Compressor discharge temperature sensor

111 '. Compressor Discharge Temperature Sensor 112. Refrigerant Injection

113. Bacteria oil tube 114. Oil separator

115. Oil return pipe 116. Oil separator check valve

117. High pressure sensor 118. Hot gas pipe

118 '. Hot gas valve 120. Accumulator

122. Low pressure sensor 130. Outdoor heat exchanger

140. Main refrigerant valve 150. Supercooler

151. Reverse transfer pipe 152. Supercooling valve

153. First sensor 154. Second sensor

155. Third sensor 156. Fourth sensor

161. Outdoor check valve 162. Outdoor solenoid valve

200. Indoor unit 210. Indoor heat exchanger

220. Expansion valve 230. Common liquid pipe

232. Branch liquid pipes 240. Common engines

242. Branching Institution

The present invention relates to an air conditioner, and more particularly, to a multi-type air conditioner that is controlled to maintain a temperature of a refrigerant discharged from a compressor below a predetermined temperature by controlling a supercooler mounted in an outdoor unit during a heating operation.

An air conditioner is a cooling / heating device that cools or heats air in an indoor space, such as an office or a house, and constitutes a series of cycles including compression, condensation, expansion, and evaporation. The air conditioner cools or heats an indoor space for air conditioning by using evaporation heat and condensation heat generated when a refrigerant, which is a working fluid, is heat-exchanged with air.

In addition to cooling / heating, air conditioners have recently been equipped with air purifying functions that suction and filter indoor contaminated air, and then return clean air to the room, and dehumidification function to re-inject humid air into wet and dry air. It will perform additional functions.

The air conditioner may be classified into a separate type air conditioner in which the outdoor unit and the indoor unit are separately installed, and an integrated air conditioner in which the outdoor unit and the indoor unit are integrally installed.

In recent years, multi-type air conditioners have been released that can be effectively applied when two or more air conditioners are installed in a home or when an air conditioner is installed in each office in a building having several offices. Such a multi-type air conditioner is connected to a plurality of indoor units in one or more outdoor units, and the same effect as installing a plurality of separate air conditioners can be obtained.

The multi-type air conditioner is installed by connecting a plurality of indoor units to one outdoor unit. An internal space of the outdoor unit includes a compressor for compressing a refrigerant, an accumulator for introducing a gaseous refrigerant into the compressor, an outdoor heat exchanger for exchanging the refrigerant, and an expansion for expanding the refrigerant in the internal space of the indoor unit. An indoor heat exchanger is installed such that the valve and the refrigerant exchange heat.

The outdoor unit and the indoor unit are connected to a pipe guiding the flow of the refrigerant, and such a pipe is formed such that the pipe connected from the outdoor unit is branched to each indoor unit so that the refrigerant flows into each indoor unit.

Looking at the flow of the refrigerant when the multi-type air conditioner is a heating operation, it is compressed to high temperature and high pressure in the compressor mounted in the internal space of the outdoor unit. The compressed refrigerant flows along the pipe and flows into the indoor unit. The compressed refrigerant flowing into the indoor unit heats up with the air in the indoor space to harmonize the air in the indoor space.

The refrigerant that is exchanged while passing through the indoor heat exchanger is converted into a state of low temperature and low pressure while passing through the expansion valve while flowing along the pipe. The refrigerant passing through the expansion valve is introduced into the internal space of the outdoor unit. The refrigerant flowing into the internal space of the outdoor unit flows to the outdoor heat exchanger and exchanges heat with air in the outdoor space while passing through the outdoor heat exchanger.

The refrigerant that exchanges heat with the air in the outdoor space flows into the accumulator. In the accumulator, the refrigerant in the liquid state is filtered out, and only the gaseous refrigerant flows into the compressor to form a refrigerant cycle.

When the air conditioner is heated, the indoor heat exchanger plays a role of a condenser, and the outdoor heat exchanger plays a role of an evaporator.

However, the following problems occur in the multi-type air conditioner according to the prior art having the configuration as described above.

The multi-type air conditioner according to the prior art includes a supercooler for supercooling a refrigerant in a pipe connected between an outdoor heat exchanger of the outdoor unit and an expansion valve of the indoor unit during a cooling operation.

In the conventional multi-type air conditioner, the subcooling valve mounted to the subcooler is shielded during the heating operation so that the refrigerant passing through the indoor heat exchanger and passing through the subcooler flows into the outdoor heat exchanger.

Therefore, the supercooler does not play any role in the multi-type air conditioner during heating operation. As the supercooler does not operate, there is a problem that the compressor is overheated by the heat generated from the refrigerant compressed to high temperature and high pressure in the internal space of the compressor and the heat generated while the compressor is operated.

In addition, the multi-type air conditioner according to the prior art cools the compressor by controlling the refrigerant injector or controlling the frequency of the compressor when the discharge temperature discharged from the compressor becomes high. The control of the refrigerant injector or the control of the compressor causes a problem that operation starts when the discharge temperature of the refrigerant reaches 103 to 112 ° C.

In addition, the cycle hunting phenomenon occurs due to the control of the coolant sprayer or the compressor, and the heating capability is lowered due to the cycle hunting phenomenon.

Due to such a problem, a problem arises in that a separate system for controlling the discharge temperature discharged from the compressor is required.

An object of the multi-type air conditioner according to the present invention for solving the above problems is to provide a multi-type air conditioner in which the temperature of the refrigerant discharged from the compressor by the supercooler during the heating operation is controlled.

Multi-type air conditioner according to the present invention for achieving the above object is a multi-type air conditioner in which a plurality of indoor units are connected by a pipe to one or more outdoor units; The outdoor unit is provided with a subcooling valve provided to the subcooler for supercooling the refrigerant to control the flow rate of the refrigerant; The subcooling valve is controlled so that the temperature of the refrigerant discharged from the compressor during the heating operation is maintained below the set temperature.

In another aspect, a multi-type air conditioner according to the present invention includes a multi-type air conditioner in which a plurality of indoor units are connected by pipes to at least one outdoor unit; The outdoor unit; A subcooling valve provided to the subcooler for supercooling the refrigerant to control a flow rate of the refrigerant; And a refrigerant injector for injecting a refrigerant into the compressor for compressing the refrigerant to prevent overheating of the compressor; During the heating operation, the subcooling valve, the refrigerant injector, and the compressor are simultaneously or selectively controlled to maintain the temperature of the refrigerant discharged from the compressor below the set temperature.

The outdoor unit includes a fourth sensor configured to sense a temperature of the refrigerant flowing through the subcooling valve to the outside of the subcooler.

The supercooling valve is purged by sensing the temperature of the refrigerant discharged from the compressor.

In another aspect, the multi-type air conditioner according to the present invention includes a multi-type air conditioner in which a plurality of indoor units are connected by pipes to at least one outdoor unit; The outdoor unit; An accumulator for allowing only a refrigerant in gaseous state to flow into the compressor; A subcooling valve provided to the subcooler for supercooling the refrigerant to control a flow rate of the refrigerant; A second sensor which senses a temperature of the refrigerant flowing out of the subcooler through the subcooling valve; It is configured to include an outdoor solenoid valve for controlling the refrigerant flowing into the outdoor heat exchanger during the heating operation; The subcooling valve and the outdoor solenoid valve are controlled individually or simultaneously so that a temperature difference between the temperature detected by the second sensor and the temperature of the refrigerant flowing into the accumulator is kept constant during the heating operation.

The subcooling valve is purged according to the temperature of the refrigerant discharged from the compressor.

According to the multi-type air conditioner according to the present invention configured as described above, there is an advantage that the heating capability is improved during the heating operation, and the system is also stably operated.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention having the configuration as described above will be described in detail.

1 is a view showing an installation state showing a multi-type air conditioner employing a preferred embodiment according to the present invention, Figure 2 is a block showing the configuration of a multi-type air conditioner employing a preferred embodiment according to the present invention A schematic is shown.

The multi-type air conditioner is installed by connecting a plurality of indoor units 200 to one or more outdoor units 100. The pipe connecting the outdoor unit 100 and the indoor unit 200 is branched to each indoor unit 200 in the pipe connected to the outdoor unit 100.

The internal space of the outdoor unit 100 includes a plurality of compressors 110 and 110 'for compressing a refrigerant at a high temperature and high pressure, an accumulator 120 for allowing gaseous refrigerant to flow into the compressors 110 and 110', and an outdoor heat exchange in which the refrigerant is heat-exchanged. 130, the main refrigerant valve 140 for controlling the flow direction of the refrigerant, the subcooler 150 for supercooling the refrigerant is mounted on the pipe connected to the indoor unit 200 in the outdoor heat exchanger (130) Is mounted.

The outdoor check valve 161 is mounted below the outdoor heat exchanger 130 to control a flow direction of the refrigerant flowing through the outdoor heat exchanger 130 into the indoor unit 200. The side of the check valve 161 is equipped with an outdoor solenoid valve 162 for controlling the amount of refrigerant flowing from the indoor unit 200 to the outdoor heat exchanger (130).

An indoor unit (200) connected to the outdoor unit (100) by pipes expands an indoor heat exchanger (210) through which air and a refrigerant in an indoor space for air conditioning exchange heat, and expands a refrigerant to flow to reduce temperature and pressure. The valve 220 and the like are mounted.

The pipe connected to the outdoor unit 100 and the indoor unit 200 is composed of a common liquid pipe 230 for guiding the refrigerant flow in the liquid state and a common engine 240 for guiding the refrigerant flow in the gas state, the common liquid pipe A branch liquid pipe 232 branching from the 230 is connected to each indoor unit 200, and a branching engine 242 branching from the common engine 240 is connected to each indoor unit 200.

The branch liquid pipe 232 and the branch engine 242 are installed so that their diameters are different depending on the capacity of the indoor unit 200 and the load capacity required for the indoor unit 200.

3 is a block diagram showing the internal configuration of a multi-type outdoor air conditioner outdoor unit employing a preferred embodiment of the present invention. Looking at the internal configuration of the outdoor unit 100 with reference to the illustrated figure, the outdoor unit 100 is formed in a rectangular parallelepiped shape in a substantially horizontal direction as a whole.

Inside the outdoor unit 100 having a rectangular parallelepiped shape, compressors 110 and 110 ′ are installed to compress the refrigerant at high temperature and high pressure. The compressors 110 and 110 ′ are formed in a cylindrical shape having a predetermined diameter, and a low noise and high efficiency scroll compressor is used. The compressors 110 and 110 'include a constant speed compressor 110 mounted on the right side and an inverter compressor 110' mounted on the left side.

The constant speed compressor 110 compresses the refrigerant at high temperature and high pressure by performing constant speed operation regardless of the load capacity, and the inverter compressor 110 'performs the shift operation according to the load capacity to compress the refrigerant at high temperature and high pressure. The inverter compressor 110 'is composed of a variable speed heat pump (Variable Speed Heat Pump) in which the rotation speed is adjusted according to the load capacity.

Therefore, when the air conditioner starts to operate, the inverter compressor 110 'is first operated according to the load capacity, and gradually increases the load capacity to exceed the capacity of the inverter compressor 110'. 110 is operated to compress the refrigerant.

The refrigerant injector 112 is mounted at the inlet side of the compressors 110 and 110 ′. The coolant sprayer 112 prevents the compressors 110 and 110 'from being burned by supplying a coolant to cool the compressors 110 and 110' when the compressors 110 and 110 'are overheated to a predetermined temperature or more. In this case, the refrigerant used is a refrigerant that flows between the supercooler 150 and the dryer 163 which will be described later.

A constant oil compressor 113 is mounted between the constant speed compressor 110 and the inverter compressor 110 ′ so that the constant speed compressor 110 and the inverter compressor 110 ′ communicate with each other. When oil supply shortage occurs in any one compressor by the fungal oil pipe 113, oil is supplemented from another compressor to prevent burnout of oil shortage.

Compressor discharge temperature sensors 111 and 111 'and an oil separator 114 for detecting the temperature of the refrigerant discharged from the compressors 110 and 110' are installed at the outlet side of the compressors 110 and 110 '. The compressor discharge temperature sensors 111 and 111 ′ are mounted at the outlet sides of the constant speed compressor 110 and the inverter compressor 110 ′, respectively, according to the temperature of the refrigerant detected by the compressor discharge temperature sensors 111 and 111 ′. By controlling the temperature of the refrigerant flowing into the 110, 110 'or increasing the amount of the refrigerant flowing into the compressor (110, 110') is prevented from being burned out.

The oil separator 114 circulates only the refrigerant by filtering the oil contained in the refrigerant discharged from the compressors 110 and 110 ', and the oil is re-introduced into the compressors 110 and 110'. That is, oil is used to reduce frictional heat when the compressors 110 and 110 'are driven, and when the refrigerant compressed to high temperature and high pressure is discharged from the compressors 110 and 110', the oil is included in the refrigerant and discharged to the outside of the compressors 110 and 110 '. . This oil is separated from the refrigerant while passing through the oil separator 114 is sent back to the interior of the compressor (110, 110 ') through the oil return pipe (115).

An oil separator check valve 116 is mounted at the outlet side of the oil separator 114. The oil separator check valve 116 is mounted at the outlet of each oil separator 114 and serves to prevent the refrigerant from flowing back to the compressor which is stopped when only one of the compressors 110 and 110 ′ is operated. Done.

The outlet side of the oil separator 114 is fastened to communicate with the main refrigerant valve 140 connected by the pipe, the main refrigerant valve 140 is composed of a four-way valve. The four-way valve has four flow paths formed in one valve to play a role of converting the flow direction of the refrigerant according to the cooling and heating operation of the air conditioner. Each port of the main refrigerant valve 140 is fastened to communicate with the accumulator 120, the outdoor heat exchanger 130, and the indoor unit 200 including the oil separator 114.

Therefore, the high temperature and high pressure refrigerant discharged from the compressors 110 and 110 ′ joins one pipe and then flows into the main refrigerant valve 140. The inlet side of the main refrigerant valve 140 is mounted with a high pressure sensor 117 for detecting the pressure of the refrigerant.

At the inlet side of the main refrigerant valve 140, a hot gas pipe 118 for guiding a part of the refrigerant flowing into the main refrigerant valve 140 from the oil separator 114 to the accumulator 120 is directly supplied to the main refrigerant valve. Skip 140 is formed so as to communicate with the inlet side of the accumulator 120.

When the hot gas pipe 118 needs to convert the low pressure refrigerant pressure flowing into the internal space of the accumulator 120 into high pressure according to the operation of the air conditioner, the high pressure refrigerant at the discharge port side of the compressors 110 and 110 ' It can be supplied directly to the inlet side of the compressor (110,110 '). The hot gas pipe 118 is equipped with a hot gas valve 118 ′ that is a bypass valve to selectively open and close the hot gas pipe 118.

The accumulator 120 is formed into a cylindrical shape having a predetermined diameter, and serves to separate the liquid refrigerant and the gas refrigerant from the internal space. As such, only the gaseous refrigerant separated from the liquid refrigerant in the accumulator 120 flows to the compressors 110 and 110 ′.

When the refrigerant in the gas state and the liquid state in the accumulator 120 are not separated, and the refrigerant remaining in the liquid state without being evaporated flows into the internal space of the compressors 110 and 110 'and the compressors 110 and 110' are operated. As the load on the compressors 110 and 110 'increases, the compressors 110 and 110' are damaged.

Therefore, the refrigerant flowing into the accumulator 120 is separated from the gas refrigerant and the liquid refrigerant by a relative weight difference. That is, since the refrigerant that is not evaporated and remains in the liquid state is relatively heavier than the refrigerant that is evaporated and is in the gas state, the refrigerant is positioned above the refrigerant in the liquid state inside the accumulator 120.

As such, only the gaseous refrigerant, which is located above the internal space of the accumulator 120, flows into the compressors 110 and 110 ′ and is compressed to a high temperature and high pressure, thereby reducing the load required for the compressors 110 and 110 ′. ) Damage can be prevented.

An inlet side of the accumulator 120 is equipped with a low pressure sensor 122 for detecting the pressure of the refrigerant flowing into the accumulator 120. The pressure sensed by the low pressure sensor 122 is converted into a temperature to calculate the temperature of the refrigerant flowing into the compressors 110 and 110 ′.

That is, when the temperature of the refrigerant flowing into the compressors 110 and 110 'becomes possible by the pressure sensed by the low pressure sensor 122, when the temperature of the compressors 110 and 110' is overheated, the temperature of the compressors 110 and 110 'is increased. It is possible to check the degree of cooling of the refrigerant flowing into the compressor (110, 110 ') to cool the.

The subcooler 150 is mounted on the side of the accumulator 120. The subcooler 150 is a subcooling means for subcooling the refrigerant, and is positioned in a pipe to which the outdoor heat exchanger 130 and the indoor unit 200 are connected.

When the air cooler 150 is operated to cool the air conditioner, the supercooled refrigerant flows to the indoor heat exchanger 210 by supercooling the coolant to improve the cooling efficiency, and when the air conditioner is heated to operate. When the refrigerant condensed in the indoor heat exchanger 210 flows to the outdoor heat exchanger 130, by overcooling the refrigerant to prevent overheating of the compressor (110,110 ') to prevent burnout of the compressor (110,110'), It will improve the heating efficiency.

The supercooler 150 is formed of a double tube, the inner tube is connected between the outdoor heat exchanger 130 and the indoor unit 200 is fastened to communicate with the refrigerant pipe for guiding the flow of the refrigerant, the outer tube is an outdoor heat exchange It is fastened so as to communicate with the reverse transfer pipe 151 which guides a part of the refrigerant flowing in the refrigerant pipe connected between the machine 130 and the indoor unit 200.

The reverse conveying pipe 151 is equipped with a subcooling valve 152 which is guided by the reverse conveying pipe 151 to cool the refrigerant flowing through the inside of the reverse conveying pipe 151 by expansion. Therefore, the refrigerant flowing from the indoor unit 200 during the heating operation of the air conditioner flows along the refrigerant pipe to pass through the subcooler 150, and the refrigerant passing through the subcooler 150 is the outdoor. It will flow to the heat exchanger (130).

The refrigerant flowing into the outdoor heat exchanger 130 flows into the accumulator 120, and the gaseous refrigerant separated from the accumulator 120 flows into the compressors 110 and 110 ′. As a result, one refrigerant cycle is completed.

In addition, a first sensor 153 for detecting a temperature of the refrigerant is mounted on the pipe between the subcooling part formed of the double pipe and the inlet side of the reverse transfer pipe 151, and the subcooling on the pipe between the subcooling valve 152 and the double pipe. The second sensor 154 for sensing the temperature of the refrigerant is mounted, and the third sensor 155 for sensing the temperature of the heat-exchanged refrigerant is mounted in the pipe for guiding the flow of the refrigerant passing through the outer tube of the double pipe.

The opening degree of the subcooling valve 152 and the outdoor solenoid valve 170 to be described later is controlled according to the temperature of the refrigerant sensed by the first sensor 153, the second sensor 154, and the third sensor 155. Done.

A dryer 163 is mounted on the pipe between the subcooler 150 and the indoor unit 200. The dryer 163 plays a role of removing moisture contained in the refrigerant flowing through the inside of the pipe.

The outdoor check valve 161 is installed at the lower side of the outdoor heat exchanger 130 to prevent the backflow of the refrigerant when the air conditioner is operated to be cooled. The heating operation of the air conditioner is provided at the side of the outdoor check valve 161. The outdoor solenoid valve 162 for controlling the flow rate of the refrigerant flowing into the interior of the outdoor heat exchanger 130 is mounted.

The outdoor check valve 161 is formed to branch from the pipe in which the outdoor solenoid valve 162 is mounted, and is formed to skip the outdoor solenoid valve 162. Therefore, the refrigerant flows through the outdoor solenoid valve 162 during the heating operation of the air conditioner, and the refrigerant flows through the outdoor check valve 161 during the cooling operation of the air conditioner.

That is, the outdoor solenoid valve 162 is mounted on a pipe between the outdoor heat exchanger 130 and the subcooler 150 to flow through the supercooler 150 during the heating operation of the air conditioner. It is controlled, and is shielded to prevent the backflow of the refrigerant during the cooling operation.

5 is a partial block diagram showing the outdoor unit configuration of a multi-type air conditioner employing a preferred embodiment of the present invention. Referring to FIG. 5 in more detail, the subcooler 150 is mounted on the refrigerant pipe guiding the flow of the refrigerant between the outdoor heat exchanger 130 and the dryer 163.

The pipe connected to the outdoor heat exchanger 130 and the subcooler 150 controls the flow rate of the refrigerant flowing into the outdoor check valve 161 and the outdoor heat exchanger 130 to restrict the flow direction of the refrigerant. The outdoor solenoid valve 162 is mounted. In addition, a first sensor 153 for sensing the temperature of the refrigerant flowing in the pipe between the outdoor solenoid valve 162 and the subcooler 150 is mounted.

A second sensor 154 is installed in the pipe between the subcooler 150 and the dryer 163 to sense the temperature of the refrigerant flowing into the subcooler 150 or passing through the subcooler 150, and the subcooling valve The pipe connecting the outer pipe 152 and the outer pipe of the double pipe is equipped with a third sensor 155 for detecting the temperature of the expanded refrigerant, and the refrigerant passing through the subcooling valve 152 is heat-exchanged and then accumulates to the accumulator 120. The pipe for guiding the flow of the refrigerant is equipped with a fourth sensor 156 that detects the temperature of the refrigerant.

That is, as shown in FIG. 5, sensors for sensing the temperature of the refrigerant are mounted on the left and right sides and the upper and lower sides of the double tube, respectively.

The overheating of the compressors 110 and 110 'is controlled by controlling the temperature of the refrigerant sensed by each sensor and the temperature of converting the pressure sensed by the low pressure sensor 122 mounted at the inlet side of the accumulator 120 into a temperature. Will be prevented.

Hereinafter, the operation of the subcooler 150 to prevent overheating of the compressors 110 and 110 'when the air conditioner is heated.

First, when the user operates the air conditioner to heat the indoor space, the compressors 110 and 110 'are operated to compress the refrigerant to high temperature and high pressure. The refrigerant compressed at high temperature and high pressure in the compressors 110 and 110 ′ flows to the oil separator 114.

The refrigerant discharged from the compressors 110 and 110 'is sensed by the compressor discharge temperature sensors 111 and 111' mounted at the discharge port side of the compressors 110 and 110 '. The overheating degree of the compressors 110 and 110 'is determined by the temperature of the refrigerant detected by the compressor discharge temperature sensors 111 and 111'.

When the air conditioner is heated and operated, the compressor 110 and 110 ′ compresses the refrigerant at a high temperature and high pressure, and the compressed refrigerant flows into the indoor unit 200 to exchange heat with the air in the indoor space. The heat exchanged refrigerant passes through the subcooler 150, passes through the outdoor solenoid valve 162, and flows through the outdoor heat exchanger 130 to the accumulator 120.

In this case, the refrigerant flowing into the accumulator 120 is detected by the low pressure sensor 122 mounted on the inlet side of the accumulator 120, and the pressure of the refrigerant detected by the low pressure sensor 122 is converted into temperature. Done. As such, when the pressure detected by the low pressure sensor 122 is converted into temperature, the temperature of the refrigerant flowing into the compressors 110 and 110 ′ can be calculated.

In addition, the refrigerant flowing from the indoor unit 200 flows by the second sensor 154 mounted between the inlet side and the double pipe of the reverse transfer pipe 151 when passing through the supercooler 150. The temperature of the refrigerant is sensed. The temperature of the refrigerant sensed by the second sensor 154 is the temperature of the refrigerant heat exchanged in the indoor unit 200.

In addition, a part of the refrigerant flowing into the reverse transfer pipe 151 is guided by the reverse transfer pipe 151 and passes through the subcooling valve 152 while passing through the reverse transfer pipe 151. The refrigerant passing through the subcooling valve 152 is formed at a low temperature by expansion, and the refrigerant formed at a low temperature flows into the outer tube of the double pipe.

The pipe between the subcooling valve 152 and the double pipe detects the temperature of the refrigerant cooled while passing through the subcooling valve 152 by the third sensor 155 mounted to check the temperature of the cooled refrigerant.

The refrigerant flowing through the subcooling valve 152 to the outer tube of the double tube is guided by the pipe connected to the outer tube of the double tube and the inlet side of the accumulator 120 and introduced into the accumulator 120. At this time, the temperature of the refrigerant heat-exchanged with the refrigerant flowing from the indoor unit 200 to the outdoor heat exchanger 130 by the fourth sensor 156 mounted on the pipe connected to the accumulator 120 and the outer tube of the double pipe. Will be detected.

The other end connected to the outer tube of the supercooler 150 and the inlet side of the accumulator 120 is formed to communicate with the pipe before passing through the low pressure sensor 122 mounted at the inlet side of the accumulator 120. do. That is, the refrigerant flowing out of the outer tube of the subcooler 150 joins with the refrigerant before passing through the low pressure sensor 122. Therefore, the low pressure sensor 122 detects the pressure of the refrigerant in a state where the refrigerant flowing out of the outer tube and the refrigerant flowing out of the outdoor heat exchanger 130 are joined together.

In the pipe connected between the inner tube of the double pipe and the outdoor solenoid valve 162, the refrigerant flowing from the indoor unit 200 to the outdoor heat exchanger 130 passes through the subcooler 150 and the subcooling valve ( The first sensor 153 is installed to sense the temperature of the refrigerant that is heat-exchanged with the refrigerant cooled by 152 and then flows to the outdoor heat exchanger 130.

Therefore, as shown in the drawing, the respective refrigerant sensors mounted on the left and right sides, the upper side, and the lower side of the double tube of the subcooler 150 pass through the refrigerant temperature and the inner tube before passing through the inner tube of the subcooler 150. The next refrigerant temperature, the refrigerant temperature before passing through the outer tube of the supercooler 150 and the refrigerant temperature after passing through the outer tube are sensed.

Hereinafter, the operation of a multi-type air conditioner employing a preferred embodiment of the present invention configured as described above will be described.

First, referring to the flow of the refrigerant during the heating operation, the refrigerant compressed by the compressors 110 and 110 ′ flows to the indoor heat exchanger 210 mounted on the indoor unit 200. The refrigerant flowing into the indoor heat exchanger 210 is heat-exchanged with the air in the indoor space, then expands and cools while passing through the expansion valve 220, and then flows into the outdoor unit 100.

The refrigerant flowing into the outdoor unit 100 passes through the subcooler 150 through the dryer 163. The refrigerant passing through the subcooler 150 flows into the outdoor heat exchanger 130 through the outdoor solenoid valve 162. The refrigerant flowing into the outdoor heat exchanger 130 is exchanged with the outside air and then introduced into the accumulator 120.

At this time, the refrigerant flowing into the accumulator 120 is joined with the refrigerant passing through the outer tube of the subcooler 150, and then the pressure of the refrigerant is sensed while passing through the low pressure sensor 122. Flows into the interior. The refrigerant flowing in the outdoor heat exchanger 130 is controlled by the outdoor solenoid valve 162.

Looking at the operation to prevent overheating of the compressor (110,110 ') during the heating operation of the multi-type air conditioner, the temperature of the refrigerant discharged from the compressor (110,110') is higher than the set temperature in the compressor discharge temperature sensor (111,111 ') When the temperature is sensed, the controller controlling the air conditioner determines that the compressors 110 and 110 'are overheated.

As such, the set temperature for determining that the compressors 110 and 110 'are overheated may vary depending on the operating condition and the load capacity of the air conditioner, but is preferably set to 80 ° C to 90 ° C, more preferably. It is set to 85 ° C.

That is, when the temperature of the refrigerant sensed by the compressor discharge temperature sensors 111 and 111 'is greater than or equal to 85 ° C., the subcooling valve 152 starts to purge. As such, when the subcooling valve 152 is purged, the refrigerant flowing along the back transfer pipe 151 is expanded more to allow more cooling.

The refrigerant cooled while passing through the subcooling valve 152 is exchanged with the refrigerant flowing in the inner tube while flowing along the outer tube of the double tube. The refrigerant heat-exchanged with the refrigerant flowing in the inner tube flows along the pipe and joins the refrigerant flowing in the outdoor heat exchanger 130 to pass through the low pressure sensor 122 to sense the pressure, and then accumulate the accumulator 120. Flows into the internal space.

In this case, the temperature calculated by converting the detected pressure of the refrigerant into a temperature is assumed to be the first temperature, and the temperature of the refrigerant flowing from the outer tube of the subcooler 150 to the accumulator 120 is referred to as a second temperature. Assuming that the subcooling valve 152 is controlled such that the second temperature-the first temperature has a constant value.

That is, when the multi-type air conditioner is heated, when the refrigerant heat exchanged in the indoor unit 200 flows to the outdoor heat exchanger 130, it is cooled by the outdoor solenoid valve 162 to the accumulator 120. Inflow. The outdoor solenoid valve 162 controls the overall temperature of the refrigerant flowing in the outdoor unit 100.

In order to prevent overheating of the compressors 110 and 110 ′, the accumulator 120 controls the supercooling valve 152 mounted on the subcooler 150 to pass through the outer tube of the supercooler 150. By flowing to the inlet side of the compressor to prevent overheating of the compressor (110,110 ').

In this case, the difference between the temperature (second temperature) of the refrigerant flowing through the outer tube of the subcooler 150 and the temperature (first temperature) of the refrigerant flowing into the accumulator 120 may be maintained. The subcooling valve 152 is controlled.

Preferably, the control is performed such that the difference between the second temperature and the first temperature is approximately 6 to 10 ° C. More preferably, the difference between the second temperature and the first temperature is controlled such that 8 ° C is maintained. As such, when the difference between the second temperature and the first temperature is maintained at 6 to 10 ° C., overheating of the compressors 110 and 110 ′ is prevented and the most efficient heating operation is possible.

On the other hand, when the heating operation of the multi-type air conditioner to look at the process of preventing the overheating of the compressor (110,110 ') by controlling the sub-cooling valve 152 mounted on the sub-cooler 150, the air conditioner to control When the controller determines whether the air conditioner is heated, the compressor discharge temperature sensors 111 and 111 ′ sense the temperature of the refrigerant discharged from the compressors 110 and 110 ′.

When the temperature of the refrigerant detected by the compressor discharge temperature sensors 111 and 111 'exceeds 80 to 90 ° C, preferably 85 ° C, the controller determines that the compressors 110 and 110' are overheated. When it is determined that the compressors 110 and 110 'are overheated, the controller controls the subcooling valve 152.

The subcooling valve 152 measures the temperature (second temperature) of the refrigerant passing through the outer tube of the subcooler 150 and the pressure sensed by the low pressure sensor 122 mounted at the inlet side of the accumulator 120. The difference of the converted temperature (first temperature) is controlled to be 6 to 10 ° C, preferably 8 ° C.

When the temperature of the refrigerant detected by the compressor discharge temperature sensors 111 and 111 'is 85 ° C. or less, the subcooling valve 152 is controlled by the controller so that the opening degree is kept constant, and the compressor discharge temperature sensors 111 and 111' are applied. When the temperature of the coolant detected at 85 ° C. exceeds 85 ° C., the degree of opening is purged and controlled to have an opening degree suitable for temperature change.

The scope of the present invention is not limited to the above-exemplified embodiments, and many other modifications based on the present invention will be possible to those skilled in the art within the above technical scope.

For example, when it is determined that the compressors 110 and 110 'are overheated, the compressor (by controlling the frequency of the subcooling valve 152, the outdoor solenoid valve 162 and the compressors 110 and 110', and the refrigerant injector simultaneously or selectively). 110, 110 ') may be possible.

In the multi-type air conditioner according to the present invention configured as described above, the refrigerant is overcooled while passing through the supercooler during the heating mode operation, thereby preventing overheating of the compressor and preventing overheating of the compressor by using a refrigerant injector.

By overcooling the refrigerant passing through the supercooler, it is possible to prevent overheating of the compressor so that a cycle hunting phenomenon does not occur in the compressor.

Since the cycle hunting phenomenon does not occur, the flow of the refrigerant is smooth and the constant is maintained, and the refrigerant is stably flowed. The stable flow of the refrigerant stabilizes the entire system of the multi-type air conditioner during the heating mode operation. It works.

In addition, the heating efficiency is improved by stabilizing the system by the stable flow of the refrigerant.

Increasing the heating efficiency improves the energy consumption efficiency, and also reduces the maintenance cost for operating the air conditioner.

In addition, since a separate system for preventing overheating of the compressor is unnecessary, the configuration is simplified, and the production cost is also reduced.

The reduction in production costs also has the effect of improving the price competitiveness of products.

Claims (6)

A multi-type air conditioner in which a plurality of indoor units are connected by pipes to at least one outdoor unit; The outdoor unit is provided with a subcooling valve provided to the subcooler for supercooling the refrigerant to control the flow rate of the refrigerant; And the subcooling valve is controlled so that the temperature of the refrigerant discharged from the compressor during the heating operation is maintained below the set temperature. A multi-type air conditioner in which a plurality of indoor units are connected by pipes to at least one outdoor unit; The outdoor unit; A subcooling valve provided to the subcooler for supercooling the refrigerant to control a flow rate of the refrigerant; And A refrigerant injector for injecting a refrigerant into a compressor for compressing the refrigerant to prevent overheating of the compressor; A multi-type air conditioner for controlling the temperature of the refrigerant discharged from the compressor to be maintained below the set temperature by simultaneously or selectively controlling the subcooling valve, the refrigerant injector, the compressor during heating operation. The outdoor unit according to claim 1 or 2, The multi-type air conditioner is provided with a fourth sensor for sensing the temperature of the refrigerant flowing through the sub-cooling valve to the outside of the sub-cooler. The method of claim 1 or 2, wherein the subcooling valve, The multi-type air conditioner of the purge control by sensing the temperature of the refrigerant discharged from the compressor. A multi-type air conditioner in which a plurality of indoor units are connected by pipes to at least one outdoor unit; The outdoor unit; An accumulator for allowing only a refrigerant in gaseous state to flow into the compressor; A subcooling valve provided to the subcooler for supercooling the refrigerant to control a flow rate of the refrigerant; A second sensor which senses a temperature of the refrigerant flowing out of the subcooler through the subcooling valve; It is configured to include an outdoor solenoid valve for controlling the refrigerant flowing into the outdoor heat exchanger during the heating operation; And a plurality of air conditioners, each of which is controlled at the same time or simultaneously with the subcooling valve and the outdoor solenoid valve so as to maintain a constant temperature difference between the temperature detected by the second sensor and the refrigerant flowing into the accumulator during the heating operation. The method of claim 3, wherein the subcooling valve, The multi-type air conditioner of the purge control according to the temperature of the refrigerant discharged from the compressor.

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