JP2011052865A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner operating indoor units in the state in which a cooling operation and a heating operation are mixed by using a double-pipeline type outdoor unit. <P>SOLUTION: This air conditioner has: the outdoor unit 2 having a compressor 20, a four-way valve 21, and an outdoor heat exchanger 22; a switch unit 3 having a four-way valve 31 which is connected to two inter-unit pipes 5 of a gas pipe 6 and a liquid pipe 7 extending from the outdoor unit 2, and to which the gas pipe 6 is connected in a state of being alternatively branched to a high-pressure gas pipe 51 and a low-pressure gas pipe 52, and an auxiliary compressor 30 of which a refrigerant suction pipe 36 is connected to the low-pressure gas pipe 52 and a refrigerant discharge pipe 34 is connected to the high-pressure gas pipe 51; and a plurality of indoor units 4A-4D having indoor heat exchangers 10A-10D which are respectively alternatively branched and connected to the high-pressure gas pipe 51 and the low-pressure gas pipe 52 at one end, and connected to the liquid pipe 7 through liquid branch pipes 18A-18D at the other end. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention has an outdoor unit and a plurality of indoor units, and the plurality of indoor units can be simultaneously operated in a cooling operation or a heating operation, or these heating operations and a cooling operation can be performed in combination. It relates to a harmony device.

  In general, an outdoor unit and a plurality of indoor units are connected via a pipe between two units composed of a liquid pipe and a gas pipe, and the plurality of indoor units are cooled or heated. A pipe connection type (hereinafter referred to as two pipe type) air conditioner is known. Further, in recent years, an outdoor unit and a plurality of indoor units are connected via three inter-unit piping composed of a low pressure gas pipe, a high pressure gas pipe, and a liquid pipe, and the plurality of indoor units are simultaneously operated for cooling or A low-pressure gas pipe, a high-pressure gas pipe and a liquid pipe connection type (hereinafter referred to as three-pipe type) air conditioner that performs heating operation or performs a mixture of these cooling operation and heating operation has been proposed. (See Patent Document 1).

Japanese Patent No. 2804527

However, in the three-pipe type air conditioner, since the outdoor unit is connected to the three inter-unit pipes, the configuration of the equipment in which the outdoor unit is pipe-connected as compared to the two-pipe type outdoor unit. In addition, the handling of pipes and piping is complicated, and the apparatus configuration tends to be enlarged. In addition, since it is necessary to provide three inter-unit piping, there are problems that the piping cost is high and the piping work is complicated.
Then, this invention solves the subject mentioned above and it aims at providing the air conditioning apparatus which can implement an indoor unit in mixed cooling operation and heating operation using a 2 piping outdoor unit. .

  In order to achieve the above object, the present invention is connected to an outdoor unit including a compressor, a four-way valve and an outdoor heat exchanger, and a pipe between two units of a gas pipe and a liquid pipe extending from the outdoor unit, A switching valve that connects the gas pipe to a high-pressure gas pipe and a low-pressure gas pipe, and a refrigerant suction pipe is connected to the low-pressure gas pipe, and a refrigerant discharge pipe is connected to the high-pressure gas pipe. A switching unit including an auxiliary compressor, one end of which is alternatively branched and connected to the high pressure gas pipe and the low pressure gas pipe, and the other end is connected to the liquid pipe via a liquid branch pipe. And a plurality of indoor units including an indoor heat exchanger.

  In this configuration, the switching valve is a single four-way valve having four ports, the gas pipe is connected to the first port of the four-way valve, the high-pressure gas pipe is connected to the second port, The low pressure gas pipe may be connected to 3 ports, and the fourth port may be connected to the refrigerant suction pipe via a connecting pipe having an opening degree adjusting valve.

  Further, the switching unit may be arranged close to the indoor unit. The refrigerant suction pipe of the switching unit is connected to a refrigerant suction branch pipe branched between the auxiliary compressor and the switching valve, and the other end of the refrigerant suction branch pipe is connected via an opening degree adjusting valve. It is also possible to adopt a configuration connected to the liquid pipe.

  Further, the auxiliary compressor of the switching unit may be configured to have at least half the capacity of the compressor of the outdoor unit.

  In addition, when the indoor unit performs cooling and heating mixed operation mainly with cooling, the switching valve blocks communication between the refrigerant discharge pipe of the compressor of the outdoor unit and the refrigerant discharge pipe of the auxiliary compressor of the switching unit. It may be configured to

  According to the present invention, the switching valve is connected to the pipe between the two units of the gas pipe and the liquid pipe extending from the outdoor unit, and the gas pipe is alternatively branched and connected to the high pressure gas pipe and the low pressure gas pipe. A switching unit including a refrigerant suction pipe connected to the low-pressure gas pipe and an auxiliary compressor connected to the high-pressure gas pipe and a refrigerant discharge pipe. By connecting a pipe-type outdoor unit and a plurality of indoor units, these indoor units can be implemented in a mixture of a cooling operation and a heating operation.

It is a circuit diagram which shows one Embodiment of the air conditioning apparatus which concerns on this invention, and shows the flow of the refrigerant | coolant at the time of this air conditioning apparatus being air-cooled. It is a circuit diagram which shows the flow of the refrigerant | coolant at the time of an air conditioning apparatus carrying out heating operation. It is a circuit diagram which shows the flow of the refrigerant | coolant at the time of an air conditioning apparatus heating-operating under cryogenic temperature. FIG. 4 is a Ph diagram illustrating the refrigerant cycle of FIG. 3. It is a circuit diagram which shows the flow of the refrigerant | coolant at the time of air-conditioning apparatus carrying out cooling-heating mixed operation by cooling main. FIG. 6 is a Ph diagram illustrating the refrigerant cycle of FIG. 5. It is a circuit diagram which shows the flow of the refrigerant | coolant at the time of an air conditioning apparatus carrying out cooling-heating mixed operation mainly by heating. FIG. 8 is a Ph diagram illustrating the refrigerant cycle of FIG. 7.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a circuit diagram showing an embodiment of an air conditioner according to the present invention. The air conditioner 1 includes a two-pipe outdoor unit 2, a plurality of (for example, four) indoor units 4A, 4B, 4C, and 4D, and the outdoor unit 2 and the indoor units 4A to 4D. And a switching unit 3 to be arranged. The switching unit 3 is connected to two inter-unit pipes 5 including a gas pipe 6 and a liquid pipe 7 extending from the outdoor unit 2, and the gas pipe 6 and the liquid pipe 7 are connected to a high pressure gas pipe 51 and a low pressure gas pipe 52. And it is a unit for switching to the liquid pipe 53 and connecting to the indoor units 4A to 4D.
In this configuration, the air conditioner 1 allows the indoor units 4A to 4D to be simultaneously cooled or heated using the two-pipe outdoor unit 2 by interposing the switching unit 3, or These cooling operation and heating operation can be mixed and implemented.

  The indoor unit 4A includes an indoor heat exchanger 10A and an indoor expansion valve 11A. One end of the indoor heat exchanger 10A is connected to the liquid pipe 53 via a liquid branch pipe 18A provided with the indoor expansion valve 11A. Connected. A branch pipe 12A is connected to the other end of the indoor heat exchanger 10A, and this branch pipe 12A branches into a high-pressure gas branch pipe 13A and a low-pressure gas branch pipe 14A. The high-pressure gas branch pipe 13A is connected to the high-pressure gas pipe 51 via the first on-off valve 15A, and the low-pressure gas branch pipe 14A is connected to the low-pressure gas pipe 52 via the second on-off valve 16A.

  The indoor unit 4A includes a temperature sensor (not shown) for detecting the inlet / outlet temperature and room temperature of the indoor heat exchanger 10A, a pressure sensor (not shown) for detecting the refrigerant pressure in the indoor heat exchanger 10A, and the like. In addition, an indoor control device (not shown) for inputting the detection results of these sensors and controlling the indoor unit 4A is provided. Since the indoor units 4B to 4D have substantially the same configuration as the indoor unit 4A, the same portions are denoted by the same reference numerals, and description thereof is omitted.

The outdoor unit 2 includes a variable capacity compressor (DC inverter compressor) 20, a four-way valve 21, an outdoor heat exchanger 22, an outdoor expansion valve 23, and a unit case 24 that accommodates them. The unit case 24 is provided with a gas pipe service valve 24A and a liquid pipe service valve 24B to which the equipment in the unit case 24 and the two pipes of the gas pipe 6 and the liquid pipe 7 are respectively connected.
The outdoor unit 2 is an existing two-pipe type (two-way) outdoor unit that can perform a cooling operation or a heating operation by switching the four-way valve 21. A refrigerant discharge pipe 25 of the compressor 20 is connected to a four-way valve 21, and the four-way valve 21 is connected to one end of an outdoor heat exchanger 22 via an in-unit gas pipe 26. The other end of the outdoor heat exchanger 22 is connected to an in-unit liquid pipe 27, and this in-unit liquid pipe 27 is connected to the liquid pipe service valve 24 </ b> B via the outdoor expansion valve 23.
On the other hand, the refrigerant suction pipe 28 of the compressor 20 is connected to a four-way valve 21, and a gas pipe service valve 24 </ b> A is connected to the four-way valve 21 via an in-unit gas pipe 29.

  The outdoor unit 2 includes pressure sensors (not shown) for detecting the suction pressure and discharge pressure of the compressor 20 and the refrigerant pressure in the outdoor heat exchanger 22, the inlet / outlet temperature of the outdoor heat exchanger 22, In addition to a temperature sensor (not shown) that detects the outside air temperature, an outdoor control device (not shown) that controls the outdoor unit 2 by inputting the detection results of these sensors is provided.

The switching unit 3 includes a variable capacity auxiliary compressor (DC inverter compressor) 30 that assists the compressor 20 of the outdoor unit 2 to form a refrigeration cycle, a four-way valve 31, and a unit case 32 that accommodates these. Is provided. The unit case 32 includes a gas pipe service valve 32A, a first liquid pipe service valve 32B, to which the equipment in the unit case 32 and the gas pipe 6 and the liquid pipe 7 of the inter-unit pipe 5 are connected, respectively, A high pressure gas pipe service valve 32C, a low pressure gas pipe service valve 32D, and a second liquid pipe service valve 32E to which the high pressure gas pipe 51, the low pressure gas pipe 52, and the liquid pipe 53 are respectively connected are provided.
In this configuration, the capacity of the auxiliary compressor 30 is configured to have at least half the capacity of the compressor 20 of the outdoor unit 2. According to this, for example, when the cooling and heating mixed operation is executed with a load balance of 50%: 50% between the cooling load and the heating load, each of the indoor units 4A to 4D using only the auxiliary compressor 30. Since the cooling and heating operations can be performed, the operation of the outdoor unit 2 can be stopped. Further, when the cooling load or the heating load is increased, for example, when the load balance is changed to 60%: 40% between the cooling load and the heating load, the outdoor unit 2 can take charge of the excess cooling load. . For this reason, the air conditioning operation with the load balance can be realized no matter how the load balance of the cooling load and the heating load of the indoor units 4A to 4D during the cooling / heating mixed operation changes.
The four-way valve 31 has four ports, and one end of the in-unit gas pipe 33 is connected to the first port A, and the other end of the in-unit gas pipe 33 is connected between the units via the gas pipe service valve 32A. It is connected to the gas pipe 6 of the pipe 5.
A refrigerant discharge pipe 34 of the auxiliary compressor 30 is connected to the second port B of the four-way valve 31. One end of a refrigerant discharge branch pipe 34A that branches between the auxiliary compressor 30 and the four-way valve 31 is connected to the refrigerant discharge pipe 34, and the other end of the refrigerant discharge branch pipe 34A is connected to a high-pressure gas pipe service valve 32C. Is connected to the high-pressure gas pipe 51. Reference numeral 35 denotes a check valve.

A refrigerant suction pipe 36 of the auxiliary compressor 30 is connected to the third port C of the four-way valve 31, and an electromagnetic opening / closing valve 37 and a check valve 38 are provided in the refrigerant suction pipe 36. The refrigerant suction pipe 36 is connected to one end of a first refrigerant suction branch pipe 36A that branches between the electromagnetic on-off valve 37 and the four-way valve 31, and the other end of the first refrigerant suction branch pipe 36A is a low-pressure gas. It is connected to the low-pressure gas pipe 52 via the pipe service valve 32D. Furthermore, one end of a second refrigerant suction branch pipe (refrigerant suction branch pipe) 36B that branches between the check valve 38 and the auxiliary compressor 30 is connected to the refrigerant suction pipe 36, and this second refrigerant suction branch pipe. The other end of 36 </ b> B is connected to the in-unit liquid pipe 40 via the opening adjustment valve 39. The in-unit liquid pipe 40 is connected to the liquid pipe 7 and the liquid pipe 53 of the inter-unit pipe 5 via the first liquid pipe service valve 32B and the second liquid pipe service valve 32E, respectively.
The fourth port D of the four-way valve 31 is connected to one end of a connecting pipe 42 having a capillary tube 41, and the other end of the connecting pipe 42 sucks refrigerant between the auxiliary compressor 30 and the check valve 38. Connected to tube 36. For example, when the outdoor unit 2 is stopped due to a thermo-off or the like, the connecting pipe 42 provided with the capillary tube 41 assists in compressing a pool of refrigerant in the indoor heat exchangers 10A to 10D connected to the outdoor unit 2. It is provided for gradually returning to the refrigerant suction pipe 36 of the machine 30 (that is, preventing the refrigerant from stagnation).
The switching unit 3 is preferably provided in the vicinity of each of the indoor units 4A to 4D. According to this configuration, it is possible to configure the air conditioner 1 by diverting the existing inter-unit pipe 5 including the gas pipe 6 and the liquid pipe 7, and the outdoor unit 2 is switched to the existing inter-unit pipe 5. With a simple configuration in which the unit 3 and the indoor units 4A to 4D are connected, the cooling operation or heating operation of each indoor unit 4A to 4D can be performed, or these cooling operation and heating operation are mixedly performed. It becomes possible to do.

Next, the operation of the air conditioner 1 will be described.
When all the indoor units 4A to 4D are cooled at the same time, as shown in FIG. 1, in the outdoor unit 2, the four-way valve 21 switches to the cooling operation position for guiding the refrigerant discharged from the compressor 20 to the outdoor heat exchanger 22. In the indoor units 4A to 4D, the first on-off valves 15A to 15D are closed and the second on-off valves 16A to 16D are opened.
In the switching unit 3, the operation of the auxiliary compressor 30 is stopped, and the four-way valve 31 communicates the gas pipe 6 and the low-pressure gas pipe 52 of the inter-unit pipe 5 (first switching position), that is, The four-way valve 31 is switched to a position where the first port A, the third port C, the second port B, and the fourth port D communicate with each other, and the electromagnetic opening / closing valve 37 and the opening degree adjusting valve 39 are closed.

Thereby, the refrigerant discharged from the compressor 20 sequentially flows into the refrigerant discharge pipe 25, the four-way valve 21, the unit internal gas pipe 26, and the outdoor heat exchanger 22, and after being condensed and liquefied in the outdoor heat exchanger 22, The liquid flows into the liquid pipe 53 through the liquid pipe 27 in the unit, the liquid pipe 7 in the inter-unit pipe 5, and the liquid pipe 40 in the unit in the switching unit 3.
The liquid refrigerant flowing through the liquid pipe 53 is distributed to the indoor expansion valves 11A to 11D of the indoor units 4A to 4D and decompressed here. The decompressed refrigerant evaporates and vaporizes in each of the indoor heat exchangers 10A to 10D, and then flows into the low pressure gas pipe 52 through the second on-off valves 16A to 16D and the low pressure gas branch pipes 14A to 14D, respectively. The gas refrigerant flowing through the low-pressure gas pipe 52 flows through the gas pipe 6 of the inter-unit pipe 5 through the first refrigerant suction branch pipe 36A, the refrigerant suction pipe 36, and the four-way valve 31 of the switching unit 3, and flows into the outdoor unit 2. The gas is sucked into the compressor 20 through the unit gas pipe 29, the four-way valve 21 and the refrigerant suction pipe 28. In this way, all the indoor units 4A to 4D are simultaneously cooled by the indoor heat exchangers 10A to 10D acting as evaporators.

When heating all the indoor units 4A to 4D simultaneously, as shown in FIG. 2, in the outdoor unit 2, the four-way valve 21 is switched to the heating operation position for guiding the refrigerant discharged from the compressor 20 to the gas pipe 6, In all the indoor units 4A to 4D, the first on-off valves 15A to 15D are opened, and the second on-off valves 16A to 16D are closed.
In the switching unit 3, the operation of the auxiliary compressor 30 is stopped and the four-way valve 31 is in a position where the gas pipe 6 of the inter-unit pipe 5 and the high-pressure gas pipe 51 communicate (second switching position), that is, The four-way valve 31 is switched to a position where the first port A, the second port B, the third port C, and the fourth port D communicate with each other, and the electromagnetic opening / closing valve 37 and the opening degree adjusting valve 39 are closed.

As a result, the refrigerant discharged from the compressor 20 flows into the gas pipe 6 of the inter-unit pipe 5 through the refrigerant discharge pipe 25, the four-way valve 21, and the intra-unit gas pipe 29. The gas refrigerant flowing through the gas pipe 6 flows into the switching unit 3, and flows into the high-pressure gas pipe 51 through the unit gas pipe 33, the four-way valve 31, the refrigerant discharge pipe 34, and the refrigerant discharge branch pipe 34A. Come on. The gas refrigerant that has flowed to the high-pressure gas pipe 51 is distributed to the high-pressure gas branch pipes 13A to 13D of the indoor units 4A to 4D, and then flows to the first on-off valves 15A to 15D and the indoor heat exchangers 10A to 10D. Here, each is condensed and liquefied. The liquefied liquid refrigerant flows into the liquid pipe 53 through the liquid branch pipes 18A to 18D.
The liquid refrigerant flowing through the liquid pipe 53 flows into the outdoor unit 2 through the in-unit liquid pipe 40 of the switching unit 3, reaches the unit internal liquid pipe 27 and the outdoor expansion valve 23 of the outdoor unit 2, and is decompressed here. . The decompressed refrigerant is evaporated and evaporated in the outdoor heat exchanger 22 and then sucked into the compressor 20 through the unit gas pipe 26, the four-way valve 21 and the refrigerant suction pipe 28. Thus, all the indoor units 4A to 4D are simultaneously heated by the indoor heat exchangers 10A to 10D acting as condensers.

  Here, for example, when the outside air temperature is remarkably lowered as in the severe winter season, it becomes difficult for the outdoor heat exchanger 22 to draw heat from the extremely low temperature outside air, so that the efficiency of the heating operation is lowered. In such a case, as shown in FIG. 3, in the switching unit 3, the auxiliary compressor 30 is operated, and the four-way valve 31 is connected to the gas pipe 6 of the inter-unit pipe 5 and the refrigerant suction pipe of the auxiliary compressor 30. 36 is switched to the first switching position for communicating with 36, and the electromagnetic on-off valve 37 and the opening degree adjusting valve 39 are opened.

As a result, the refrigerant discharged from the compressor 20 flows into the gas pipe 6 of the inter-unit pipe 5 through the refrigerant discharge pipe 25, the four-way valve 21, and the intra-unit gas pipe 29. The gas refrigerant flowing through the gas pipe 6 flows into the switching unit 3, and is sucked into the auxiliary compressor 30 through the in-unit gas pipe 33, the four-way valve 31, and the refrigerant suction pipe 36 of the switching unit 3. 30 is compressed in two stages. The refrigerant discharged from the auxiliary compressor 30 flows into the high-pressure gas pipe 51 through the refrigerant discharge pipe 34 and the refrigerant discharge branch pipe 34A. The gas refrigerant that has flowed to the high-pressure gas pipe 51 is distributed to the high-pressure gas branch pipes 13A to 13D of the indoor units 4A to 4D, and then flows to the first on-off valves 15A to 15D and the indoor heat exchangers 10A to 10D. Here, each is condensed and liquefied. The liquefied liquid refrigerant flows into the liquid pipe 53 through the liquid branch pipes 18A to 18D.
The liquid refrigerant flowing through the liquid pipe 53 flows into the in-unit liquid pipe 40 of the switching unit 3 and is branched into two by the in-unit liquid pipe 40. One liquid refrigerant flows through the second refrigerant suction branch pipe 36B and the opening adjustment valve 39, and after being depressurized by the opening adjustment valve 39, flows into the refrigerant suction pipe 36 of the auxiliary compressor 30, and this refrigerant suction pipe At 36, the refrigerant merged with the refrigerant discharged from the compressor 20 of the outdoor unit 2 is sucked into the auxiliary compressor 30. The other liquid refrigerant flows into the outdoor unit 2, reaches the unit liquid pipe 27 of the outdoor unit 2, and the outdoor expansion valve 23, where it is depressurized, and this depressurized refrigerant passes through the outdoor heat exchanger 22. After evaporating and evaporating, the air is sucked into the compressor 20 through the unit internal gas pipe 26, the four-way valve 21 and the refrigerant suction pipe 28.

FIG. 4 is a Ph diagram illustrating the refrigerant cycle of FIG. 3. In FIG. 4, points a to g indicate the relationship between the pressure and the enthalpy at the positions denoted by the same reference numerals in FIG.
In this configuration, since the discharge refrigerant compressed by the compressor 20 is compressed in two stages by the auxiliary compressor 30 of the switching unit 3, the condensation in the indoor heat exchangers 10A to 10D to which the discharge refrigerant of the auxiliary compressor 30 is supplied. The pressure (condensation temperature) can be kept high, and the heating operation in the indoor units 4A to 4D can be performed even when the outside air temperature is extremely low. In this case, part of the liquid refrigerant condensed in the indoor heat exchangers 10 </ b> A to 10 </ b> D is returned to the suction side of the auxiliary compressor 30 via the second refrigerant suction branch pipe 36 </ b> B and the opening degree adjustment valve 39. Therefore, the suction refrigerant temperature of the auxiliary compressor 30 can be lowered, and when the discharge pressure of the auxiliary compressor 30 is increased to a desired discharge pressure, the discharge temperature of the auxiliary compressor 30 increases excessively. Can be prevented.

When the indoor units 4A to 4D perform cooling / heating mixed operation mainly by cooling, for example, when the indoor units 4A to 4C are cooling operation and the indoor unit 4D is heating operation, as shown in FIG. The four-way valve 21 is switched to the cooling operation position for guiding the refrigerant discharged from the compressor 20 to the outdoor heat exchanger 22, and in the indoor units 4A to 4C, the first on-off valves 15A to 15C are closed, and the second on-off valves 16A to 16A. 16C is opened, and in the indoor unit 4D, the first on-off valve 15D is opened and the second on-off valve 16D is closed.
In the switching unit 3, the auxiliary compressor 30 is operated, the four-way valve 31 is switched to the first switching position, the electromagnetic on-off valve 37 is opened, and the opening degree adjusting valve 39 is closed.

Thereby, the refrigerant discharged from the compressor 20 sequentially flows into the refrigerant discharge pipe 25, the four-way valve 21, the unit internal gas pipe 26, and the outdoor heat exchanger 22, and after being condensed and liquefied in the outdoor heat exchanger 22, The liquid flows into the liquid pipe 53 through the liquid pipe 27 in the unit, the liquid pipe 7 in the inter-unit pipe 5, and the liquid pipe 40 in the unit in the switching unit 3.
On the other hand, the refrigerant discharged from the auxiliary compressor 30 flows into the indoor unit 4D through the refrigerant discharge pipe 34, the refrigerant discharge branch pipe 34A, and the high-pressure gas pipe 51. The refrigerant flowing into the indoor unit 4D flows to the indoor heat exchanger 10D through the high-pressure gas branch pipe 13D and the first on-off valve 15D, where it is condensed and liquefied, and then flows into the liquid pipe 53 through the liquid branch pipe 18D. Then, it merges with the refrigerant discharged from the compressor 20 of the outdoor unit 2 in the liquid pipe 53.
The liquid refrigerant flowing through the liquid pipe 53 is distributed to the indoor expansion valves 11A to 11C of the indoor units 4A to 4C, where the pressure is reduced. The decompressed refrigerant is evaporated and vaporized in each of the indoor heat exchangers 10A to 10C, and then the second on-off valves 16A to 16C and the low pressure gas branch pipes 14A to 14C are respectively connected to the switching unit 3 through the low pressure gas pipe 52. It flows in and is divided into two in this switching unit 3.
One refrigerant is sucked into the auxiliary compressor 30 through the first refrigerant suction branch pipe 36 </ b> A and the refrigerant suction pipe 36. The other refrigerant flows into the outdoor unit 2 through the refrigerant suction pipe 36, the four-way valve 31, and the gas pipe 6, and is sucked into the compressor 20 through the in-unit gas pipe 29, the four-way valve 21, and the refrigerant suction pipe 28. . In this way, the indoor units 4A to 4C are each cooled by the indoor heat exchangers 10A to 10C acting as evaporators, and the indoor unit 4D is heated by the other indoor heat exchanger 10D acting as a condenser.

FIG. 6 is a Ph diagram illustrating the refrigerant cycle of FIG. In general, when the indoor unit is operated mainly in the cooling and cooling operation, the outside air temperature is considered to be lower than in the summer, and therefore the condensation temperature in the refrigerant cycle can be lowered by the amount of the outside air temperature.
However, in the conventional three-pipe air conditioner, the outdoor heat exchanger of the outdoor unit and the indoor heat exchanger of the indoor unit communicate with each other via a high-pressure gas pipe. In order to execute the operation, the condensation temperature in the outdoor heat exchanger, that is, the discharge pressure (high pressure) of the compressor must be increased compared to the outside air temperature.
On the other hand, in this configuration, the switching unit 3 is disposed between the outdoor unit 2 and the indoor units 4A to 4D, and the refrigerant discharge pipe 25 of the compressor 20 and the auxiliary compressor are driven by the four-way valve 31 of the switching unit 3. 30 refrigerant discharge pipes 34 are cut off. For this reason, as shown in FIG. 6, compared with the discharge pressure (cd in FIG. 6) of the auxiliary compressor 30 which contributes to the heating operation of the indoor unit 4D, the discharge pressure (a− in FIG. 6). f) can be kept low, and the amount of work (power consumption) of the compressor 20 can be reduced.
Moreover, in this embodiment, since the auxiliary compressor 30 has about half the capacity of the compressor 20, for example, when the cooling load and the heating load of the indoor units 4A to 4D are balanced (50:50), Since the operation of the compressor 20 is stopped and the air-conditioning operation can be performed only by the auxiliary compressor 30, the power consumption of the air conditioner 1 can be reduced.

When the indoor units 4A to 4D are in a cooling / heating mixed operation mainly with heating, for example, when the indoor unit 4A is in cooling operation and the indoor units 4A to 4D are in heating operation, as shown in FIG. The four-way valve 21 is switched to the heating operation position for guiding the refrigerant discharged from the compressor 20 to the gas pipe 6, and in the indoor unit 4A, the first on-off valve 15A is closed, the second on-off valve 16A is opened, In the units 4B to 4D, the first on-off valves 15B to 15D are opened, and the second on-off valves 16B to 16D are closed.
In the switching unit 3, the auxiliary compressor 30 is operated, and the four-way valve 31 is switched to the second switching position where the gas pipe 6 of the inter-unit pipe 5 and the refrigerant discharge pipe 34 of the auxiliary compressor 30 communicate with each other. The electromagnetic opening / closing valve 37 is opened, and the opening adjustment valve 39 is closed.

As a result, the refrigerant discharged from the compressor 20 flows into the gas pipe 6 of the inter-unit pipe 5 through the refrigerant discharge pipe 25, the four-way valve 21, and the intra-unit gas pipe 29. The gas refrigerant flowing through the gas pipe 6 flows into the in-unit gas pipe 33, the four-way valve 31, and the refrigerant discharge pipe 34 of the switching unit 3.
On the other hand, the refrigerant discharged from the auxiliary compressor 30 flows into the refrigerant discharge pipe 34 and merges with the refrigerant discharged from the compressor 20 of the outdoor unit 2 in the refrigerant discharge pipe 34. The combined refrigerant is distributed to the high pressure gas branch pipes 13B to 13D of the indoor units 4B to 4D through the refrigerant discharge branch pipe 34A and the high pressure gas pipe 51, and then the first on-off valves 15B to 15D and the indoor heat exchanger. 10B to 10D, where each is condensed and liquefied. The liquefied liquid refrigerant flows into the liquid pipe 53 through the liquid branch pipes 18B to 18D.
A part of the liquid refrigerant that has flowed into the liquid pipe 53 flows into the indoor unit 4A and is decompressed by the indoor expansion valve 11A of the indoor unit 4A. The decompressed refrigerant is evaporated by the indoor heat exchanger 10A. . The vaporized gas refrigerant flows into the switching unit 3 through the second on-off valve 16A, the low-pressure gas branch pipe 14A, and the low-pressure gas pipe 52, and the auxiliary compressor 30 through the first refrigerant suction branch pipe 36A and the refrigerant suction pipe 36. Inhaled.
On the other hand, the remainder of the liquid refrigerant flowing into the liquid pipe 53 flows into the outdoor unit 2 through the unit liquid pipe 40 of the switching unit 3 and reaches the unit liquid pipe 27 and the outdoor expansion valve 23 of the outdoor unit 2. At reduced pressure. The decompressed refrigerant is evaporated and evaporated in the outdoor heat exchanger 22 and then sucked into the compressor 20 through the unit gas pipe 26, the four-way valve 21 and the refrigerant suction pipe 28. In this way, the indoor unit 4A is cooled by the indoor heat exchanger 10A acting as an evaporator, and the indoor units 4B to 4D are heated by the other indoor heat exchangers 10B to 10D acting as condensers.

FIG. 8 is a Ph diagram illustrating the refrigerant cycle of FIG.
In general, when the cooling operation is performed in the season when the outside air temperature is low, such as in winter, the outdoor heat exchanger needs to lower the evaporation temperature in order to pump up heat from the low temperature outside air. In the conventional three-pipe type air conditioner, the outdoor heat exchanger of the outdoor unit and the indoor heat exchanger of the indoor unit communicate with each other via a low-pressure gas pipe. Therefore, the evaporation temperature in the indoor heat exchanger is In some cases, the operation efficiency is lowered, and the indoor heat exchanger is frozen to interrupt the cooling operation.
On the other hand, in this configuration, the switching unit 3 is disposed between the outdoor unit 2 and the indoor units 4A to 4D, and the refrigerant suction pipe 28 and the auxiliary compressor 30 of the compressor are provided by the four-way valve 31 of the switching unit 3. The refrigerant suction pipe 36 is cut off. Therefore, as shown in FIG. 8, the evaporation temperature (evaporation pressure; fc in FIG. 8) in the indoor heat exchanger 10 </ b> A when the indoor unit 4 </ b> A is cooled is used as the evaporation temperature in the outdoor heat exchanger 22. (Evaporation pressure; ga in FIG. 6) can be set higher, and the cooling operation of the indoor unit 4A can be performed efficiently.
Moreover, in this embodiment, since the auxiliary compressor 30 has about half the capacity of the compressor 20, for example, when the cooling load and the heating load of the indoor units 4A to 4D are balanced (50:50), Since the operation of the compressor 20 is stopped and the air-conditioning operation can be performed only by the auxiliary compressor 30, the power consumption of the air conditioner 1 can be reduced.

  As described above, according to this embodiment, the outdoor unit 2 including the compressor 20, the four-way valve 21 and the outdoor heat exchanger 22, and the gas pipe 6 and the liquid pipe 7 extending from the outdoor unit 2 are provided. A four-way valve 31 that connects the gas pipe 6 to a high-pressure gas pipe 51 and a low-pressure gas pipe 52, and a refrigerant suction pipe 36 is connected to the low-pressure gas pipe 52. In addition, the switching unit 3 including the auxiliary compressor 30 to which the refrigerant discharge pipe 34 is connected to the high-pressure gas pipe 51, one end of which is alternatively branched and connected to the high-pressure gas pipe 51 and the low-pressure gas pipe 52, Since the other end includes a plurality of indoor units 4A to 4D including the indoor heat exchangers 10A to 10D connected to the liquid pipe 7 via the liquid branch pipes 18A to 18D, a so-called two-pipe outdoor unit is provided. 2 with indoor unit A~4D can be carried in a mixed cooling operation and heating operation of.

  Moreover, according to this embodiment, since the switching unit 3 is arrange | positioned in proximity to indoor unit 4A-4D, the existing inter-unit piping 5 which consists of the gas pipe 6 and the liquid pipe 7 is diverted, and air conditioning is carried out. The apparatus 1 can be configured, and the indoor unit 4A to 4D can be cooled by a simple configuration in which the outdoor unit 2, the switching unit 3 and the indoor units 4A to 4D are connected to the existing inter-unit pipe 5. The heating operation can be performed, or the cooling operation and the heating operation can be performed in combination.

  Further, according to the present embodiment, one end of the second refrigerant suction branch pipe 36B branched between the auxiliary compressor 30 and the four-way valve 31 is connected to the refrigerant suction pipe 28 of the switching unit 3, and this second Since the other end of the refrigerant suction branch pipe 36B is connected to the unit internal liquid pipe 40 via the opening degree adjusting valve 39, the four-way valve 31 is switched to the first switching position and opened during the heating operation of the indoor units 4A to 4D. By opening the degree adjustment valve 39, a part of the liquid refrigerant condensed in the indoor heat exchangers 10A to 10D of the indoor units 4A to 4D is mixed with the refrigerant discharged from the compressor 20 of the outdoor unit 2. The auxiliary compressor can be inhaled. For this reason, the discharge refrigerant compressed by the compressor 20 is compressed in two stages by the auxiliary compressor 30 of the switching unit 3, thereby condensing in the indoor heat exchangers 10A to 10D to which the discharge refrigerant of the auxiliary compressor 30 is supplied. The pressure (condensation temperature) can be kept high, and the heating operation in the indoor units 4A to 4D can be performed even when the outside air temperature is extremely low.

  Moreover, according to this embodiment, since the auxiliary compressor 30 of the switching unit 3 has at least half the capacity of the compressor 20 of the outdoor unit 2, for example, the cooling load and the heating load are 50%: 50%. When the cooling / heating mixed operation is executed with the load balance, the cooling and heating operation of each of the indoor units 4A to 4D can be performed using only the auxiliary compressor 30, and thus the operation of the outdoor unit 2 is stopped. be able to. Further, when the cooling load or the heating load is increased, for example, when the load balance is changed to 60%: 40% between the cooling load and the heating load, the outdoor unit 2 can take charge of the excess cooling load. . For this reason, the air conditioning operation with the load balance can be realized no matter how the load balance of the cooling load and the heating load of the indoor units 4A to 4D during the cooling / heating mixed operation changes.

  Further, according to the present embodiment, when the indoor units 4 </ b> A to 4 </ b> D perform the cooling / heating mixed operation mainly with the cooling, the four-way valve 31 includes the refrigerant discharge pipe 25 of the compressor 20 of the outdoor unit 2 and the switching unit 3. Since the communication with the refrigerant discharge pipe 34 of the auxiliary compressor 30 is cut off, the discharge pressure of the compressor 20 can be suppressed lower than the discharge pressure of the auxiliary compressor 30 supplied to the indoor unit 4D that is heated. The work amount (power consumption) of the compressor 20 can be reduced.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to this. For example, in the present embodiment, the switching unit 3 is configured to include the four-way valve 31 as a switching valve. However, the configuration is not limited to this, and a configuration in which an electromagnetic on-off valve is combined in place of the four-way valve 31 may be provided. The switching unit 3 is configured to accommodate the four-way valve 31 in the unit case 32, but the four-way valve 31 may be provided outside the unit case 32.

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 2 Outdoor unit 3 Switching unit 4A-4D Indoor unit 5 Inter-unit piping 6 Gas pipe 7 Liquid pipe 20 Compressor 21 Four-way valve 22 Outdoor heat exchanger 30 Auxiliary compressor 31 Four-way valve 32 Unit case 34 Refrigerant discharge pipe 34A Refrigerant discharge branch pipe 36 Refrigerant suction pipe 36A First refrigerant suction branch pipe 36B Second refrigerant suction branch pipe 37 Electromagnetic on-off valve 39 Opening adjustment valve 40 Unit internal liquid pipe 42 Connecting pipe 51 High pressure gas pipe 52 Low pressure gas pipe 53 Liquid tube

Claims (6)

An outdoor unit comprising a compressor, a four-way valve and an outdoor heat exchanger;
A switching valve connected to a pipe between two units of a gas pipe and a liquid pipe extending from the outdoor unit, and connecting the gas pipe into a high-pressure gas pipe and a low-pressure gas pipe, and the low-pressure gas pipe; A switching unit including a refrigerant suction pipe and an auxiliary compressor connected to the high-pressure gas pipe and a refrigerant discharge pipe;
A plurality of indoor units including an indoor heat exchanger whose one end is alternatively branched and connected to the high-pressure gas pipe and the low-pressure gas pipe and the other end is connected to the liquid pipe via the liquid branch pipe And an air conditioner.   The switching valve is a single four-way valve having four ports, the gas pipe is connected to a first port of the four-way valve, the high-pressure gas pipe is connected to a second port, and the gas is connected to a third port. The air conditioning apparatus according to claim 1, wherein a low-pressure gas pipe is connected, and the fourth port is connected to the refrigerant suction pipe via a connecting pipe having an opening degree adjusting valve.   The air conditioning apparatus according to claim 1 or 2, wherein the switching unit is disposed in proximity to the indoor unit.   A refrigerant suction branch pipe branched between the auxiliary compressor and the switching valve is connected to the refrigerant suction pipe, and the other end of the refrigerant suction branch pipe is connected to the liquid pipe via an opening degree adjusting valve. The air conditioner according to any one of claims 1 to 3, wherein the air conditioner is connected.   The air conditioner according to any one of claims 1 to 4, wherein the auxiliary compressor of the switching unit has at least half the capacity of the compressor of the outdoor unit.   When each indoor unit performs cooling and heating mixed operation mainly by cooling, the switching valve blocks communication between the refrigerant discharge pipe of the compressor of the outdoor unit and the refrigerant discharge pipe of the auxiliary compressor of the switching unit. The air conditioner according to any one of claims 1 to 5, wherein

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