JP2011237119A - Refrigerating cycle device - Google Patents

Abstract

A pressure loss in a gas connection pipe is reduced when all the indoor units in operation are in cooling or heating operation.
In a refrigeration cycle apparatus in which a plurality of outdoor units, a plurality of indoor units, and a gas connection pipe and a liquid connection pipe are connected in parallel, the gas connection pipe is provided between the outdoor unit and the indoor unit. And an indoor first on-off valve that branches and merges into the first main gas connection pipe and the second main gas connection pipe, and that can open and close the flow path between the first main gas connection pipe and the indoor unit, An indoor second on-off valve capable of opening and closing a flow path between the main gas connection pipe and the indoor unit, an outdoor first on-off valve capable of opening and closing a flow path between the first main gas connection pipe and the outdoor unit, An outdoor flow path check valve that allows only the flow from the second main gas connection pipe to the outdoor unit is provided between the second main gas connection pipe and the outdoor unit, and the indoor first on-off valve and the indoor unit 2 Open the on-off valve and the outdoor first on-off valve
[Selection] Figure 1

Description

  The present invention relates to a refrigeration cycle apparatus capable of simultaneous cooling and heating operations in which a plurality of outdoor units and a plurality of indoor units are connected in parallel.

  Multiple outdoor units and multiple indoor units are connected in parallel using high-pressure gas piping, low-pressure gas piping, and liquid piping to form a refrigeration cycle, allowing simultaneous cooling and heating in each of the multiple indoor units There is known a refrigeration apparatus, for example, Patent Document 1.

  This refrigeration apparatus includes a plurality of outdoor units, a plurality of indoor units, a main liquid line, a main high-pressure gas line, a main low-pressure gas line, and a piping unit.

  The outdoor unit includes a compressor, a heat source side heat exchanger in which one end is switchably connected to a discharge side and a suction side of the compressor and a liquid line is connected to the other end, and a heat source side provided in the liquid line Pressure reducing means. And the base end of the gas line branched into a high-pressure passage allowing refrigerant flow from the compressor in the discharge direction and a low-pressure passage allowing refrigerant flow in the compressor suction direction are connected to the discharge side and suction side of the compressor. Switchable connection.

  The main liquid line, main high-pressure gas line, and main low-pressure gas line are connected to the liquid line, high-pressure passage, and low-pressure passage of each outdoor unit so that the heat source units are connected in parallel.

  The indoor unit has a use side heat exchanger having one end connected to the main liquid line, and a use side pressure reducing means provided between the use side heat exchanger and the main liquid line. The other end of the use side heat exchanger is connected to the main high-pressure gas line and the main low-pressure gas line in a switchable manner.

  The piping unit includes a check valve that allows refrigerant to flow from the outdoor unit to the main high-pressure gas line, and a check valve that allows refrigerant to flow from the main low-pressure gas line to the outdoor unit.

  In the case of simultaneous cooling / heating operation in which some of the plurality of indoor units perform cooling operation and at least one other performs heating operation, some outdoor units compress the discharge side of the compressor to the heat source side heat exchanger. The cooling mode is such that the suction side of the machine communicates with the low-pressure passage, and the other outdoor units have the operation mode such that the discharge side of the compressor is a high-pressure passage and the suction side of the compressor is a heating cycle that communicates with the heat source side heat exchanger. Be controlled.

Japanese Patent No. 3289366

  However, in the above-mentioned patent document, when all the indoor units are in the cooling operation (including the case where the operating indoor unit is in the cooling operation and the other indoor units are stopped), the gas refrigerant is only in the main low-pressure gas line. When all the indoor units are in the heating operation (including the case where the operating indoor unit is in the heating operation and the other indoor units are stopped), the gas refrigerant is allowed to flow only in the main high-pressure gas line. For this reason, in the cooling operation, there is a problem that the pressure loss in the main low-pressure gas line increases, and in the heating operation, the pressure loss in the main high-pressure gas line increases, and the performance of the refrigeration cycle apparatus is likely to deteriorate.

  An object of the present invention is to provide a refrigeration cycle apparatus capable of reducing pressure loss in a gas connection pipe when all indoor units in operation perform cooling operation.

  Another object of the present invention is to provide a refrigeration cycle apparatus capable of reducing pressure loss in a gas connection pipe when all indoor units in operation perform heating operation.

  To achieve the above object, the present invention provides a plurality of outdoor units having a compressor, a four-way valve, an outdoor heat exchanger, an outdoor pressure reducing device, and a plurality of indoor units having an indoor pressure reducing device and an indoor heat exchanger. A refrigeration cycle apparatus comprising a plurality of outdoor units and a plurality of gas connection pipes and liquid connection pipes that connect the plurality of indoor units in parallel, wherein the plurality of indoor units can be operated simultaneously with cooling and heating. The gas connection pipe branches into and merges with the first main gas connection pipe and the second main gas connection pipe between the outdoor unit and the indoor unit, and the first main gas connection pipe and the indoor unit A first indoor open / close valve capable of opening and closing a flow path between the unit, a second indoor open / close valve capable of opening and closing a flow path between the second main gas connection pipe and the indoor unit, and the first main Gas connection Between the second main gas connection pipe and the outdoor unit between the second main gas connection pipe and the outdoor unit. An outdoor flow path check valve that allows only the indoor first open / close valve downstream of the activated indoor unit when all of the activated indoor units are in cooling operation. And the second indoor opening / closing valve, the first outdoor opening / closing valve upstream of the outdoor unit in which the compressor is activated among the plurality of outdoor units is opened, and the refrigerant discharged from the indoor unit branches. And flowing through the first main gas connection pipe and the second main gas connection pipe and joining the outdoor unit after joining.

  A plurality of outdoor units having a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor pressure reducing device; a plurality of indoor units having an indoor pressure reducing device and an indoor heat exchanger; the plurality of outdoor units; A refrigeration cycle apparatus comprising a gas connection pipe and a liquid connection pipe for connecting a plurality of indoor units in parallel, wherein the plurality of indoor units can be operated simultaneously with cooling and heating, wherein the gas connection pipe includes the outdoor unit The first main gas connection pipe and the second main gas connection pipe branch and merge between the unit and the indoor unit, and the flow path can be opened and closed between the first main gas connection pipe and the indoor unit. An indoor first on-off valve, an indoor second on-off valve capable of opening and closing a flow path between the second main gas connection pipe and the indoor unit, and between the first main gas connection pipe and the outdoor unit. Flow An outdoor first on-off valve capable of opening and closing, and an outdoor second on-off valve capable of opening and closing a flow path between the second main gas connection pipe and the outdoor unit, and is activated among the plurality of indoor units. When all indoor units are in heating operation, the first indoor open / close valve and the second indoor open / close valve upstream of the activated indoor unit are opened, and the compressor is activated among the plurality of outdoor units. The outdoor first on-off valve and the outdoor second on-off valve downstream of the outdoor unit are opened, and the refrigerant discharged from the outdoor unit branches to connect the first main gas connection pipe and the second main gas connection It flows through the pipe and enters the indoor unit after merging.

  ADVANTAGE OF THE INVENTION According to this invention, when all the indoor units in operation perform air_conditionaing | cooling operation, the pressure loss in a gas connection pipe | tube can be reduced.

  Moreover, when all the indoor units in operation perform heating operation, the pressure loss in the gas connection pipe can be reduced.

It is a refrigerant circuit figure at the time of all the indoor unit air_conditionaing | cooling operation showing the structure of the refrigerating-cycle apparatus in the 1st Embodiment of this invention. It is a time chart figure showing operation of each valve at the time of all indoor unit air conditioning operation showing the composition of the refrigerating cycle device in a 1st embodiment of the present invention. It is a refrigerant circuit figure at the time of all the indoor unit heating operation showing the structure of the refrigerating-cycle apparatus in the 1st Embodiment of this invention. It is a time chart figure showing operation of each valve at the time of all indoor unit heating operation showing composition of a refrigerating cycle device in a 1st embodiment of the present invention. It is a refrigerant circuit figure at the time of cooling and heating simultaneous operation showing the composition of the refrigerating cycle device in a 1st embodiment of the present invention. It is a time chart showing operation of each valve at the time of cooling and heating simultaneous operation showing composition of a refrigerating cycle device in a 1st embodiment of the present invention. It is a refrigerant circuit figure at the time of all the indoor unit heating operation showing the structure of the refrigerating-cycle apparatus in the 2nd Embodiment of this invention. It is a time chart figure showing operation of each valve at the time of all indoor unit heating operation showing composition of a refrigerating cycle device in a 2nd embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to FIGS.

  FIG. 1 is a refrigerant circuit diagram in a case where all indoor units representing the configuration of the refrigeration cycle apparatus according to the first embodiment of the present invention are performing a cooling operation. The refrigeration cycle apparatus of the present embodiment includes two outdoor units 1a and 1b and three indoor units (No. 1 to No. 3) 3a to 3c, a main liquid connection pipe 7, a first main gas connection pipe 5, A refrigeration cycle is configured by connecting in parallel using three connecting pipes of two main gas connecting pipes 6.

  Each indoor unit (No. 1 to No. 3) 3a to 3c is composed of indoor heat exchangers 31a to 31c and indoor expansion valves 32a to 32c, and one end of the indoor heat exchangers 31a to 31c and indoor liquid connection pipes 33a to 33c. Are connected via the indoor expansion valves 32a to 32c, and the other ends of the indoor heat exchangers 31a to 31c and the indoor gas connection pipes 34a to 34c are connected. The indoor gas connection pipes 34a to 34c are connected to the first main gas connection pipe 5 and the second main gas connection pipe 6 via the indoor switching units 4a to 4c.

  In the indoor switching units 4a to 4c, piping connected to the indoor gas connection pipes 34a to 34c is branched into two systems, and one piping system is connected to the first main gas connection pipe 5 via the indoor first on-off valves 41a to 41c. The other piping system is connected to the second main gas connection pipe 6 via the indoor second on-off valves 42a to 42.

  The outdoor units 1a and 1b include compressors 10a and 10b, four-way valves 12a and 12b, outdoor heat exchangers 13a and 13b, outdoor expansion valves 14a and 14b, liquid blocking valves 15a and 15b, gas blocking valves 16a and 16b, and accumulators. 17a and 17b are provided and sequentially connected by piping. In the middle of the piping connecting the discharge sides of the compressors 10a, 10b and the four-way valves 12a, 12b, backflow prevention valves 11a, 11b are provided to prevent refrigerant from entering the discharge sides of the compressors 10a, 10b. Each outdoor unit 1a, 1b is connected to two pipes, an outdoor liquid connection pipe 18a, 18b and an outdoor gas connection pipe 19a, 19b. One end of each of the outdoor liquid connection pipes 18 a and 18 b is connected to the liquid blocking valves 15 a and 15 b, and the other end is connected to join the main liquid connection pipe 7. One end of the outdoor gas connection pipes 19a and 19b is connected to the gas blocking valves 16a and 16b, and the other end is connected to the first main gas connection pipe 5 and the second main gas connection pipe 6 via the outdoor switching units 2a and 2b. Connected to.

  In the outdoor switching units 2a and 2b, pipes connected to the outdoor gas connection pipes 19a and 19b are branched into two systems, and one pipe system is connected to the first main gas connection pipe 5 via the outdoor first on-off valves 21a and 21b. The second main gas connection pipe is connected to the other main pipe via the outdoor flow check valves 22a and 22b that allow the other pipe system to flow only from the second main gas connection pipe 6 to the outdoor gas connection pipes 19a and 19b. 6 is connected. The outdoor switching units 2a and 2b are individually connected to the outdoor units 1a and 1b, respectively, and are all the same.

<All rooms cooling operation>
Next, in this embodiment, the operation when all the connected indoor units perform the cooling operation will be described with reference to FIG. 1 or FIG. In the present embodiment, the capacity of one indoor unit is set to be half of the capacity of one outdoor unit, and the two outdoor units are assumed to have the same capacity.

  The indoor unit when the indoor heat exchanger functions as an evaporator is set as a cooling operation, and the indoor unit when the indoor heat exchanger is used as a condenser is set as a heating operation. The same shall apply hereinafter.

  FIG. 2 is a time chart showing the operation of each valve during the all-unit indoor unit cooling operation representing the configuration of the refrigeration cycle apparatus according to the first embodiment of the present invention. In the figure, as operations of the outdoor unit and the outdoor switching unit, the solid line represents the outdoor unit No. 1a 1a, and the broken line represents the outdoor unit No. 2 1b. Further, as operations of the indoor unit and the indoor switching unit, the solid line represents the indoor unit No. 1 machine 3a, the broken line represents the indoor unit No. 2 machine 3b, and the alternate long and short dash line represents the indoor unit No. 3 machine 3c.

  Considering the actual use, multiple indoor units are centrally managed and may start and stop at the same time, or may start and stop as needed as soon as a resident enters each room. . FIG. 2 shows an example in which the indoor units are individually started and stopped. The same applies to the following time charts.

  First, immediately after the power is supplied to the outdoor units 1a and 1b and the indoor units 3a to 3c, the four-way valves 12a and 12b are in the cooling mode (the discharge side of the compressor and the outdoor heat to operate the outdoor heat exchanger as a condenser). The outdoor first on-off valves 21a and 21b, the indoor first on-off valves 41a to 41c, and the indoor second on-off valves 42a to 42c are all closed.

  Next, when the indoor unit No. 1 3a starts the cooling operation, the outdoor unit No. 1a is set to be activated preferentially as the activation priority of the outdoor unit (the outdoor unit No. 2 1b is preferentially activated by the rotation control). Therefore, the compressor 10a of the outdoor unit No. 1 la is adjusted to a frequency necessary for cooling the indoor unit No. 1 3a. At this time, the outdoor first on-off valve 21a of the outdoor switching unit 2a, the indoor first on-off valve 41a, and the indoor second on-off valve 42a of the indoor switching unit 4a are opened at the same time as or before the operation of the compressor 10a starts.

  Next, when the indoor unit No. 2 machine 3b starts the cooling operation, the indoor first opening / closing valve 41b and the indoor second opening / closing valve 42b of the indoor switching unit 4b open, and the operating frequency of the compressor 10a of the outdoor unit No. 1a increases. To do. Since the total operating capacity of the indoor unit No. 1 unit 3a and the indoor unit No. 2 unit 3b is less than or equal to the capacity of the outdoor unit No. 1 unit 1a, the operation can be performed below the upper limit frequency of the compressor 10a of the outdoor unit No. 1 unit 1a. Only unit 1a is operated.

  Next, when the indoor unit No. 3 machine 3c starts the cooling operation, the indoor first opening / closing valve 41c and the indoor second opening / closing valve 42c of the indoor switching unit 4c are opened. Since the total operating capacity of all the indoor units 3a to 3c is equal to or greater than the capacity of the outdoor unit No. 1 la, the operation of the outdoor unit No. 1 b is started, and the outdoor first on-off valve 21b of the outdoor switching unit 2b is opened. The compressors 10a and 10b of the outdoor units 1a and 1b are adjusted to frequencies necessary for generating a capacity for cooling operation corresponding to 1.5 indoor units.

  Next, when the indoor unit No. 3 machine 3c stops the cooling operation, the indoor first opening / closing valve 41c of the indoor switching unit 4c is closed in order to prevent liquid refrigerant accumulation in the indoor unit No. 3 machine 3c and to prepare for simultaneous cooling and heating operation. Thus, the indoor second on-off valve 42c is kept open. The cooling capacity of the indoor unit No. 1 3a and the indoor unit No. 2 3b is half of the total capacity of the outdoor unit No. 1a and the outdoor unit No. 1b. Therefore, each outdoor unit generates half the rated capacity. It is adjusted to the frequency necessary to

  Next, when the indoor unit No. 1 unit 3a stops the cooling operation, the indoor first opening / closing valve 41a of the indoor switching unit 4a is closed in order to prevent storage of liquid refrigerant in the indoor unit No. 1 unit 3a and to prepare for simultaneous cooling and heating operation. Thus, the indoor second on-off valve 42a is kept open. The cooling operation capacity of the indoor unit No. 2 unit 3b is ¼ of the total capacity of the outdoor unit No. 1 unit 1a and the outdoor unit No. 2 unit 1b, and the operation efficiency of the two outdoor units decreases. Therefore, the operation of the outdoor unit No. 1a 1a, which has started the operation first, is stopped, the operation is continued only by the outdoor unit No. 2 1b, and the compressor 10b of the outdoor unit No. 2 1b is the indoor unit 2 The frequency is adjusted to a frequency required for generating the cooling operation capacity of the machine 3b. At this time, the outdoor first opening / closing valve 21a of the outdoor switching unit 2a is closed from the viewpoint of reducing standby power and preventing refrigerant from entering the stop outdoor unit.

  Next, when the indoor unit No. 2 machine 3b stops the cooling operation, the indoor first opening / closing valve 41b of the indoor switching unit 4b is closed in order to prevent liquid refrigerant accumulation in the indoor unit No. 2 machine 3b and to prepare for simultaneous cooling and heating operation. Thus, the indoor second on-off valve 42b is kept open. And since all the indoor units will be in a stop state, the outdoor unit No. 2 machine 1b will also stop, and the outdoor 1st on-off valve 21b of the outdoor switching unit 2b also from a viewpoint of standby power reduction and the refrigerant | coolant approach prevention to a stop outdoor unit. Closed.

  In the above operation, when all the indoor units are performing the cooling operation, the refrigerant flows in the refrigeration cycle apparatus shown in FIG. In the two outdoor units 1a and 1b, the gas refrigerant that has become high temperature and high pressure in the compressors 10a and 10b flows into the four-way valves 12a and 12b through the piping on the discharge side of the compressors 10a and 10b. Since the four-way valves 12a and 12b operate so that the discharge sides of the compressors 10a and 10b communicate with the outdoor heat exchangers 13a and 13b, the gas refrigerant that has passed through the four-way valves 12a and 12b becomes the outdoor heat exchanger 13a, Flows into 13b. Here, in the outdoor heat exchangers 13a and 13b, a heat radiation cycle is formed by causing the outdoor heat exchangers 13a and 13b to act as condensers by exchanging heat with the inflowing air. The condensed liquid refrigerant is supplied to the outdoor liquid connection pipes 18a and 18b via the liquid blocking valves 15a and 15b. The liquid refrigerant supplied to the outdoor liquid connection pipes 18a and 18b merges, passes through the main liquid connection pipe 7, and is divided into the indoor liquid connection pipes 33a to 33c connected to the indoor units 3a to 3c. It flows into 3a-3c. In each of the indoor units 3a to 3c, the pressure is reduced by the indoor expansion valves 32a to 32c, the temperature becomes low and low pressure, flows into the indoor heat exchangers 31a to 31c, and heat is exchanged with the air flowing into the indoor heat exchangers 31a to 31c. The exchangers 31a to 31c act as an evaporator, and the indoor side can be cooled by removing heat from the air. The refrigerant evaporated in the indoor heat exchangers 31a to 31c passes through the indoor gas connection pipes 34a to 34c and flows into the indoor switching units 4a to 4c. When all the indoor units that continue to operate are performing the cooling operation, the indoor first opening / closing valves 41a to 41c and the indoor second opening / closing valves 42a to 42c attached to the indoor switching units 4a to 4c are in an open state. Therefore, the evaporated refrigerant flows in both the first main gas connection pipe 5 and the second main gas connection pipe 6, and flows into the outdoor switching units 2a and 2b. In the outdoor switching units 2a and 2b, the first outdoor open / close valves 21a and 21b provided are opened, and the outdoor flow check valves 22a and 22b are connected from the second main gas connection pipe 6 to the outdoor gas connection pipe. It is installed so that the refrigerant flows toward 19a and 19b. For this reason, the refrigerant that has flowed through the first main gas connection pipe 5 and the second main gas connection pipe 6 passes through the outdoor first on-off valves 21a and 21b and the outdoor flow path check valves 22a and 22b, and joins the outdoor. The refrigerant flows into the gas connection pipes 19a and 19b, flows into the accumulators 17a and 17b through the gas blocking valves 16a and 16b, and the four-way valves 12a and 12b, and is guided to the suction side of the compressors 10a and 10b and compressed again. A refrigeration cycle is formed.

<All rooms heating operation>
Next, in this embodiment, the operation when all the indoor units to be connected perform the heating operation will be described with reference to FIG. 3 or FIG. FIG. 3 is a refrigerant circuit diagram showing the configuration of the refrigeration cycle apparatus according to the first embodiment of the present invention during all-room unit heating operation, and FIG. 4 shows the configuration of the refrigeration cycle apparatus according to the first embodiment of the present invention. It is a time chart figure showing operation of each valve at the time of all indoor unit heating operation to express. 3 or 4, the same reference numerals and the same line types as those in FIG. 1 or 2 indicate the same elements.

  First, immediately after the power is supplied to the outdoor units 1a and 1b and the indoor units 3a to 3c, the same state as in the all-room cooling operation is obtained.

  Next, when the indoor unit No. 1 3a starts the heating operation, the outdoor unit No. 1 1a is set to be activated preferentially as the activation priority of the outdoor unit (the outdoor unit No. 2 1b is preferentially activated by the rotation control). Therefore, the compressor 10a of the outdoor unit No. 1 machine 1a is adjusted and operated to a frequency necessary for heating the indoor unit No. 1 machine 3a. At this time, the outdoor first opening / closing valve 21a of the outdoor switching unit 2a and the indoor first opening / closing valve 41a of the indoor switching unit 4a are opened simultaneously with the start of operation of the compressor 10a or before the start of operation. Then, the four-way valve 12a of the outdoor unit No. 1a 1a is switched to the heating mode (connected so that the discharge side of the compressor communicates with the gas blocking valve).

  Next, when the indoor unit No. 2 machine 3b starts the heating operation, the indoor first opening / closing valve 41b of the indoor switching unit 4b opens, and the operating frequency of the compressor 10a of the outdoor unit No. 1 la increases. Since the total operating capacity of the indoor unit No. 1 unit 3a and the indoor unit No. 2 unit 3b is less than or equal to the capacity of the outdoor unit No. 1 unit 1a, the operation can be performed below the upper limit frequency of the compressor 10a of the outdoor unit No. 1 unit 1a. Only unit 1a is operated.

  Next, when the indoor unit No. 3 machine 3c starts the heating operation, the indoor first opening / closing valve 41c of the indoor switching unit 4c is opened. Since the total operating capacity of all the indoor units 3a to 3c is equal to or greater than the capacity of the outdoor unit No. 1 la, the operation of the outdoor unit No. 1 b is started, and the outdoor first on-off valve 21b of the outdoor switching unit 2b is opened. Then, the four-way valve 12b of the outdoor unit No. 2 machine 1b is switched to the heating mode (connected so that the discharge side of the compressor and the gas blocking valve communicate with each other), and the compressors 10a, 10b of the outdoor units 1a, 1b are The frequency is adjusted to generate a capacity required for heating operation of 1.5 indoor units.

  Next, when the indoor unit No. 3 machine 3c stops the heating operation, the indoor first opening / closing valve 41c of the indoor switching unit 4c is closed to prevent liquid refrigerant from being stored in the indoor unit No. 3 machine 3c. The heating capacity of the indoor unit No. 1 unit 3a and the indoor unit No. 2 unit 3b is half of the total capacity of the outdoor unit No. 1a and the outdoor unit No. 2 unit 1b, so that each outdoor unit generates half the rated capacity. Is adjusted to the necessary frequency.

  Next, when the indoor unit No. 1 unit 3a stops the heating operation, the indoor first opening / closing valve 41a of the indoor switching unit 4a is closed to prevent liquid refrigerant from being stored in the indoor unit No. 1 unit 3a. The heating operation capacity of the indoor unit No. 2 unit 3b is ¼ of the total capacity of the outdoor unit No. 1a and the outdoor unit No. 2 unit 1b, and the operation efficiency of the two outdoor units decreases. In consideration of leveling, the operation of the outdoor unit No. 1a 1a which has started the operation first is stopped, and the frequency required for generating the heating operation capacity of the indoor unit No. 2 unit 3b only by the outdoor unit No. 2 1b is adjusted. The operation is continued. At this time, the four-way valve 12a of the outdoor unit No. 1a and the outdoor first on-off valve 21a of the outdoor switching unit 2a are kept open from the standpoints of continuing standby for heating operation and suppressing refrigerant sealing to the high pressure side.

  Next, when the indoor unit No. 2 machine 3b stops the heating operation, the indoor first opening / closing valve 41b of the indoor switching unit 4b is closed to prevent liquid refrigerant from being stored in the indoor unit No. 2 machine 3b. And since all the indoor units will be in a stop state, the outdoor unit No. 2 machine 1b will also stop, the four-way valve 12b of the outdoor unit No. 2 machine 1b, and the outdoor 1st on-off valve 21b of the outdoor switching unit 2b will also continue heating operation standby From the viewpoint of suppressing the refrigerant sealing to the high pressure side, it is held open.

  In the above operation, when all the indoor units are performing the heating operation, in the refrigeration cycle apparatus shown in FIG. In the two outdoor units 1a and 1b, the gas refrigerant that has become high temperature and high pressure in the compressors 10a and 10b flows into the four-way valves 12a and 12b through the piping on the discharge side of the compressors 10a and 10b. Since the four-way valves 12a and 12b operate so that the discharge sides of the compressors 10a and 10b communicate with the gas blocking valves 16a and 16b, the gas refrigerant that has passed through the four-way valves 12a and 12b passes through the gas blocking valves 16a and 16b. , Flows into the outdoor switching units 2a, 2b through the outdoor gas connection pipes 19a, 19b. The outdoor first open / close valves 21a and 21b attached to the outdoor switching units 2a and 2b are in an open state, and the outdoor flow check valves 22a and 22b are connected from the second main gas connection pipe 6 to the outdoor gas connection pipe 19a. , 19b, the high-temperature and high-pressure gas refrigerant is supplied only to the first main gas connection pipe 5. The gas refrigerant supplied to the first main gas connection pipe 5 is divided and flows into the indoor switching units 4a to 4c. In each indoor switching unit 4a-4c, since only the indoor first on-off valves 41a-41c are open, the gas refrigerant flowing through the first main gas connection pipe 5 passes through the indoor first on-off valves 41a-41c. It flows into the indoor gas connection pipes 34a to 34c and flows into the indoor units 3a to 3c. The gas refrigerant that has flowed into the indoor units 3a to 3c flows into the indoor heat exchangers 31a to 31c, and exchanges heat with the air that flows into the indoor heat exchangers 31a to 31c, thereby condensing the indoor heat exchangers 31a to 31c. The indoor side can be heated by releasing heat to the air. The liquid refrigerant condensed in the indoor heat exchangers 31a to 31c passes through the indoor expansion valves 32a to 32c, flows into the indoor liquid connection pipes 33a to 33c, joins, and is supplied to the main liquid connection pipe 7. The liquid refrigerant supplied to the main liquid connection pipe 7 is diverted, passes through the outdoor liquid connection pipes 18a and 18b of the outdoor units 1a and 1b, and is supplied to the outdoor units 1a and 1b. The liquid refrigerant supplied to the outdoor units 1a and 1b passes through the liquid blocking valves 15a and 15b, is depressurized by the outdoor expansion valves 14a and 14b, becomes low temperature and low pressure, and flows into the outdoor heat exchangers 13a and 13b. In the outdoor heat exchangers 13a and 13b, an endothermic cycle is formed by causing the outdoor heat exchangers 13a and 13b to function as an evaporator by exchanging heat with the inflowing air. Then, the evaporated refrigerant flows into the accumulators 17a and 17b via the four-way valves 12a and 12b, and the refrigerant is led to the suction side of the compressors 10a and 10b and compressed again to form a refrigeration cycle.

<Simultaneous cooling and heating>
Next, in this embodiment, the operation when the connected indoor unit performs the cooling and heating simultaneous operation will be described with reference to FIG. 5 or FIG. FIG. 5 shows a refrigerant circuit diagram during the cooling and heating simultaneous operation representing the configuration of the refrigeration cycle apparatus in the first embodiment of the present invention, and FIG. 6 shows the cooling and heating configuration representing the configuration of the refrigeration cycle apparatus in the first embodiment of the present invention. It is a time chart figure showing operation of each valve at the time of simultaneous operation. 5 or 6, the same reference numerals and the same line types as those in FIG. 1 or 4 indicate the same elements.

  First, immediately after power is supplied to the outdoor unit and the indoor unit, the same state as in the all-indoor unit cooling operation and the all-indoor unit heating operation is obtained.

  Next, when the indoor unit No. 1 3a starts the cooling operation, the outdoor unit No. 1a is set to be activated preferentially as the activation priority of the outdoor unit (the outdoor unit No. 2 1b is preferentially activated by the rotation control). Therefore, the compressor 10a of the outdoor unit No. 1 la is adjusted to a frequency necessary for cooling the indoor unit No. 1 3a. At this time, the outdoor first on-off valve 21a of the outdoor switching unit 2a, the indoor first on-off valve 41a and the indoor second on-off valve 42a of the indoor switching unit 4a are opened simultaneously with the start of the operation of the compressor 10a or before the start of the operation. That is, the same operation as the all-room cooling operation is performed.

  Next, when the indoor unit No. 2 machine 3b starts the heating operation, the indoor first opening / closing valve 41b of the indoor switching unit 4b is opened. Since the outdoor unit No. 1 la is operated by forming a heat release cycle for the cooling operation of the indoor unit No. 1 3 a, high temperature and high pressure gas refrigerant cannot be sent to the indoor unit No. 2 b side. Therefore, by operating the outdoor unit No. 2 machine 1b as an endothermic cycle, it operates to supply a high-temperature and high-pressure gas refrigerant to the indoor unit No. 2 machine 3b. That is, the compressor 10b of the outdoor unit No. 2 machine 1b is adjusted and operated to a frequency necessary for heating the indoor unit No. 2 machine 3b. The operation is performed at a predetermined operation frequency, and the four-way valve 12b of the outdoor unit No. 2 machine 1b is switched to the heating mode (connected so that the discharge side of the compressor and the gas blocking valve communicate with each other). At this time, since the outdoor gas connection pipe 19a of the outdoor unit No. 1a is in a low pressure state, the gas refrigerant discharged from the outdoor unit No. 2 1b flows into the outdoor unit No. 1a, and enters the indoor unit No. 2 3b. On the other hand, in order to prevent the high-temperature and high-pressure gas refrigerant from being unable to be supplied, the outdoor switching unit connected to the outdoor unit No. 1 la at the same time or before the start of the operation of the outdoor unit No. 1 b. The outdoor first open / close valve 21a of 2a is closed. Then, the indoor first on-off valve 41a of the indoor switching unit 4a is closed so that the high-temperature and high-pressure gas refrigerant does not enter the indoor unit No. 1 machine 3a that is continuing the cooling operation.

  Next, when the indoor unit No. 3 machine 3c starts the cooling operation, the indoor second on-off valve 42c of the indoor switching unit 4c is opened. Since the total operating capacity of the indoor unit No. 1 3a and the indoor unit No. 3 3c that are performing the cooling operation is equal to or less than the capacity of the outdoor unit No. 1a that forms the heat radiation cycle, the compressor 10a of the outdoor unit No. 1a The operating frequency increases to a value necessary for cooling the indoor unit No. 1 3a and the indoor unit No. 3 3c.

  Next, when the indoor unit No. 3 machine 3c stops the cooling operation, the indoor second on-off valve 42c of the indoor switching unit 4c is kept open to prevent liquid refrigerant from being stored in the indoor unit No. 3 machine 3c. The operating frequency of the compressor 10a of the first unit 1a is lowered to a value necessary for cooling the indoor unit first unit 3a.

  Next, when the indoor unit No. 1 machine 3a stops the cooling operation, the indoor second opening / closing valve 42a of the indoor switching unit 4a is kept open to prevent liquid refrigerant from being stored in the indoor unit No. 1 machine 3a. At this time, since the cooling operation on the indoor unit side is all stopped, the heat radiation cycle of the outdoor unit No. 1 la that is required for the indoor unit to perform the cooling operation is not necessary. For this reason, the operation frequency of the compressor 10a of the outdoor unit No. 1 la is 0, and the operation of the outdoor unit No. 1 la is stopped. At this time, the operation of the outdoor unit No. 2 1b is continued in a state where the endothermic cycle is formed in order for the indoor unit No. 2 3b to continue the heating operation.

  Next, when the indoor unit No. 2 machine 3b stops the heating operation, the indoor first opening / closing valve 41b of the indoor switching unit 4b is closed to prevent liquid refrigerant from being stored in the indoor unit No. 2 machine 3b. And since all the indoor units will be in a stopped state, the operating frequency of the compressor 10b of the outdoor unit No. 2 machine 1b will be 0, and the outdoor unit No. 2 machine 1b will also stop. At this time, the four-way valve 12b of the outdoor unit No. 2 machine 1b and the outdoor first on-off valve 21b of the outdoor switching unit 2b are held in an open state from the standpoint of continuing the heating operation and suppressing the sealing of the refrigerant to the high pressure side.

  In the above operation, in the case of the cooling / heating simultaneous operation in which the indoor unit No. 1 3a and the indoor unit No. 3 3c perform the cooling operation and the indoor unit No. 3 3b performs the heating operation, in the refrigeration cycle apparatus shown in FIG. As indicated by the arrows, the refrigerant flows through the heating action as indicated by the dashed arrows. In the outdoor unit No. 1 la, the gas refrigerant that has become high temperature and high pressure in the compressor 10a flows into the four-way valve 12a through the piping on the discharge side of the compressor 10a. Since the four-way valve 12a operates so that the discharge side of the compressor 10a and the outdoor heat exchanger 13a communicate with each other, the gas refrigerant that has passed through the four-way valve 12a flows into the outdoor heat exchanger 13a. Here, in the outdoor heat exchanger 13a, a heat radiation cycle is formed by causing the outdoor heat exchanger 13a to act as a condenser by exchanging heat with the inflowing air. The condensed liquid refrigerant is supplied to the main liquid connection pipe 7 through the outdoor liquid connection pipe 18a via the outdoor expansion valve 14a and the liquid blocking valve 15a.

  On the other hand, in the outdoor unit No. 2 1b, the gas refrigerant that has become high temperature and high pressure in the compressor 10b flows into the four-way valve 12b through the piping on the discharge side of the compressor 10b. Since the four-way valve 12b operates so that the discharge side of the compressor 10b and the gas blocking valve 16b communicate with each other, the gas refrigerant that has passed through the four-way valve 12b passes through the gas blocking valve 16b and the outdoor gas connection pipe 19b and is switched to the outdoor side. It flows into the unit 2b. The outdoor first open / close valve 21b attached to the outdoor switching unit 2b is open, and the outdoor flow check valve 22b flows from the second main gas connection pipe 6 toward the outdoor gas connection pipe 19b. Therefore, the high-temperature and high-pressure gas refrigerant is supplied only to the first main gas connection pipe 5. The gas refrigerant supplied to the first main gas connection pipe 5 is divided and flows into the indoor switching units 4a to 4c. Here, since only the indoor first opening / closing valve 41b of the indoor switching unit 4b connected to the indoor unit No. 2 machine 3b that performs the heating operation is in an open state, only the indoor gas connection pipe 34b connected to the indoor unit No. 2 machine 3b has a high temperature. A high-pressure gas refrigerant is supplied and flows into the indoor unit No. 2 machine 3b. The high-temperature and high-pressure gas refrigerant flowing into the indoor unit No. 2 machine 3b flows into the indoor heat exchanger 31b and exchanges heat with the air flowing into the indoor heat exchanger 31b, so that the indoor heat exchanger 31b acts as a condenser. The indoor side can be heated by releasing heat to the air. The liquid refrigerant condensed in the indoor heat exchanger 31b passes through the indoor expansion valve 32b, flows into the indoor liquid connection pipe 33b, and joins the main liquid connection pipe 7.

  The liquid refrigerant supplied to the main liquid connection pipe 7 from the outdoor unit No. 1 machine 1a and the liquid refrigerant supplied to the main liquid connection pipe 7 from the indoor unit No. 2 machine 3b performing the heating operation are performing the cooling operation. The flow is diverted to the outdoor liquid connection pipe 18b of each of the indoor unit No. 1 machine 3a, the indoor unit No. 3 machine 3c, and the outdoor unit No. 2 machine 1b. The liquid refrigerant branched into the indoor unit No. 1 machine 3a and the indoor unit No. 3 machine 3c passes through the indoor liquid connection pipes 33a and 33c and is reduced in pressure by the indoor expansion valves 32a and 32c to become low temperature and low pressure, and the indoor heat exchangers 31a and 31c. The indoor heat exchangers 31a and 31c act as evaporators by exchanging heat with the air flowing into the indoor heat exchangers 31a and 31c, and the indoor side can be cooled by removing heat from the air. The refrigerant evaporated in the indoor heat exchangers 31a and 31c passes through the indoor gas connection pipes 34a and 34c and flows into the indoor switching units 4a and 4c. The indoor switching units 4a and 4c connected to the indoor unit No. 1 machine 3a and the indoor unit No. 3 machine 3c have the indoor first on-off valves 41a and 41c closed and the indoor second on-off valves 42a and 42c open. Therefore, the evaporated refrigerant flows only in the second main gas connection pipe 6 and is divided into the outdoor switching units 2a and 2b connected to the outdoor unit No. 1a and the outdoor unit No. 2b, respectively. The refrigerant branched to the outdoor switching unit 2b on the outdoor unit 2 unit 1b side has a high pressure in the outdoor gas connection pipe 19b because the outdoor unit 2 unit 1b forms an endothermic cycle. Since the stop valve 22b is pushed by the pressure of the outdoor gas connection pipe 19b, the flow is cut off with respect to the outdoor unit No. 2 machine 1b side. In addition, the refrigerant diverted to the outdoor switching unit 2a on the outdoor unit No. 1a side has an outdoor flow because the outdoor unit No. 1a forms a heat dissipation cycle, so the pressure in the outdoor gas connection pipe 19a is low. The road check valve 22a is opened and flows into the outdoor unit No. 1 la through the outdoor gas connection pipe 19a. The refrigerant that has flowed into the outdoor unit No. 1a flows into the accumulator 17a via the gas blocking valve 16a and the four-way valve 12a, and the refrigerant is led to the suction side of the compressor 10a and compressed again to form a refrigeration cycle. The On the other hand, the liquid refrigerant divided into the outdoor liquid connecting pipe 18b of the outdoor unit No. 1b passes through the liquid blocking valve 15b, is decompressed by the outdoor expansion valve 14b, becomes low temperature / low pressure, and flows into the outdoor heat exchanger 13b. In the outdoor heat exchanger 13b, an endothermic cycle is formed by causing the outdoor heat exchanger 13b to function as an evaporator by exchanging heat with the inflowing air. Then, the evaporated refrigerant flows into the accumulator 17b through the four-way valve 12b, and the refrigerant is guided to the suction side of the compressor 10b and compressed again to form a refrigeration cycle.

  As described above, when all the indoor units are performing the cooling operation, the low-pressure refrigerant that has been evaporated in the indoor heat exchanger passes through both the first main gas connection pipe and the second main gas connection pipe. Therefore, the pressure loss on the low-pressure side is reduced to half, and the degree of reduction in cooling capacity that occurs when the connecting pipe becomes long can be halved compared to the conventional refrigeration cycle. That is, it is possible to improve the operating efficiency of the refrigeration cycle during the cooling operation. In this embodiment, the indoor units are activated one by one, but all the indoor units may be activated all at once. In addition, even if some indoor units are air-cooled and there are indoor units that do not start, if the connection pipe is long with a large refrigeration cycle device, the pressure loss on the low-pressure side is reduced by half, and air-conditioning operation is performed. The operating efficiency of the refrigeration cycle at the time can be improved.

  In addition, a common small piping unit that does not depend on the number of outdoor units connected is provided in the gas connection pipe of each outdoor unit, and it can be switched between cooling and heating, and is connected by two pipes, a liquid connection pipe and a gas connection pipe. By using a plurality of simple outdoor units, a refrigeration cycle apparatus capable of simultaneous cooling and heating can be provided. It is not necessary to use a dedicated unit corresponding to the number of outdoor units to be connected, such as a piping unit necessary for connecting the gas-side refrigerant piping of each outdoor unit to the main high-pressure gas line and the low-pressure gas line. . Therefore, it is not necessary to manufacture several types of piping units, and the manufacturing cost can be suppressed. Furthermore, even if the number of connected outdoor units increases, the number of components housed like the piping unit increases, so that the volume of the piping unit increases and the installation area does not increase.

  FIG. 7 is a refrigerant circuit diagram in a case where all the indoor units representing the configuration of the refrigeration cycle apparatus in the second embodiment of the present invention are performing a heating operation. In the figure, the same reference numerals and the same line types as those in FIG. In the refrigeration cycle apparatus of the present embodiment, the outdoor second open / close valves 23a and 23b are used instead of the outdoor flow path check valves 22a and 22b provided in the outdoor switching units 2a and 2b connected to the outdoor units 1a and 1b. Is provided.

  Next, operation | movement of the refrigerating-cycle apparatus of a present Example is demonstrated. FIG. 8 is a time chart illustrating the operation of each valve during the all-indoor unit heating operation, which represents the configuration of the refrigeration cycle apparatus according to the second embodiment of the present invention.

  First, immediately after supplying power to the outdoor unit and the indoor unit, the state is the same as in the first embodiment of the present example.

  Next, when the indoor unit No. 1 3a starts the heating operation, the outdoor unit No. 1 1a is set to be activated preferentially as the activation priority of the outdoor unit (the outdoor unit No. 2 1b is preferentially activated by the rotation control). Therefore, the compressor 10a of the outdoor unit No. 1 machine 1a is adjusted and operated to a frequency necessary for heating the indoor unit No. 1 machine 3a. At this time, the outdoor first on-off valve 21a, the outdoor second on-off valve 23a of the outdoor switching unit 2a, the indoor first on-off valve 41a and the indoor second on-off valve 42a of the indoor switching unit 4a are simultaneously with the start of the operation of the compressor 10a. Or open before the start of operation. Then, the four-way valve 12a of the outdoor unit No. 1a 1a is switched to the heating mode (connected so that the discharge side of the compressor communicates with the gas blocking valve).

  Next, when the indoor unit No. 2 machine 3b starts the heating operation, the indoor first opening / closing valve 41b and the indoor second opening / closing valve 42b of the indoor switching unit 4b open, and the operating frequency of the compressor 10a of the outdoor unit No. 1a increases. To do. Since the total operating capacity of the indoor unit No. 1 unit 3a and the indoor unit No. 2 unit 3b is less than or equal to the capacity of the outdoor unit No. 1 unit 1a, it is possible to operate below the upper limit frequency of the compressor 10a of the outdoor unit No. 1 unit 1a. Only unit 1 machine 1a is operated.

  Next, when the indoor unit No. 3 machine 3c starts the heating operation, the indoor first opening / closing valve 41c and the indoor second opening / closing valve 42c of the indoor switching unit 4c are opened. Since the total operation capacity of all the indoor units 3a to 3c is equal to or greater than the capacity of the outdoor unit No. 1 la, the operation of the outdoor unit No. 1 b is started, and the outdoor first on-off valve 21b and the outdoor No. 1 of the outdoor switching unit 2b are started. 2 Open / close valve 23b is opened. Then, the four-way valve 12b of the outdoor unit No. 2 machine 1b is switched to the heating mode (connected so that the discharge side of the compressor and the gas blocking valve communicate with each other), and the compressors 10a, 10b of the outdoor units 1a, 1b are The frequency is adjusted to generate a capacity required for heating operation of 1.5 indoor units.

  Next, when the indoor unit No. 3 machine 3c stops the heating operation, the indoor first on-off valve 41c and the indoor second on-off valve 42c of the indoor switching unit 4c are set to prevent liquid refrigerant from being stored in the indoor unit No. 3 machine 3c. Close. The heating capacity of the indoor unit No. 1 unit 3a and the indoor unit No. 2 unit 3b is half of the total capacity of the outdoor unit No. 1a and the outdoor unit No. 2 unit 1b, so that each outdoor unit generates half the rated capacity. Is adjusted to the necessary frequency.

  Next, when the indoor unit No. 1 unit 3a stops the heating operation, the indoor first on-off valve 41a and the indoor second on-off valve 42a of the indoor switching unit 4a are set to prevent liquid refrigerant accumulation in the indoor unit No. 1 unit 3a. Close. The heating operation capacity of the indoor unit No. 2 unit 3b is ¼ of the total capacity of the outdoor unit No. 1a and the outdoor unit No. 2 unit 1b, and the operation efficiency of the two outdoor units decreases. In consideration of leveling, the operation of the outdoor unit No. 1a 1a which has started the operation first is stopped, and the frequency required for generating the heating operation capacity of the indoor unit No. 2 unit 3b only by the outdoor unit No. 2 1b is adjusted. The operation is continued. At this time, the four-way valve 12a of the outdoor unit No. 1a, and the outdoor first on-off valve 21a and the outdoor second on-off valve 23a of the outdoor switching unit 2a are from the viewpoint of continuing standby for heating operation and preventing refrigerant sealing to the high pressure side. The open state is maintained.

  Next, when the indoor unit No. 2 machine 3b stops the heating operation, the indoor first on-off valve 41b and the indoor second on-off valve 42b of the indoor switching unit 4b are set to prevent liquid refrigerant accumulation in the indoor unit No. 2 machine 3b. Close. And since all the indoor units will be in a stop state, the outdoor unit No. 2 machine 1b will also stop, the four-way valve 12b of the outdoor unit No. 2 machine 1b, the outdoor 1st on-off valve 21b, and the outdoor 2nd on-off valve of the outdoor switching unit 2b. 23b is also kept open from the standpoint of continuing the heating operation and suppressing the sealing of the refrigerant to the high pressure side.

  In the above operation, when all the indoor units are performing the heating operation, the refrigerant flows in the refrigeration cycle apparatus shown in FIG. In the two outdoor units 1a and 1b, the gas refrigerant that has become high temperature and high pressure in the compressors 10a and 10b flows into the four-way valves 12a and 12b through the piping on the discharge side of the compressors 10a and 10b. Since the four-way valves 12a and 12b operate so that the discharge sides of the compressors 10a and 10b communicate with the gas blocking valves 16a and 16b, the gas refrigerant that has passed through the four-way valves 12a and 12b passes through the gas blocking valves 16a and 16b. , Flows into the outdoor switching units 2a, 2b through the outdoor gas connection pipes 19a, 19b. Since the outdoor first on-off valves 21a and 21b and the outdoor second on-off valves 23a and 23b attached to the outdoor switching units 2a and 2b are both open, the first main gas connection pipe 5 and the second main gas connection pipe Both are supplied with high-temperature and high-pressure gas refrigerant. The gas refrigerant supplied to the first main gas connection pipe 5 and the second main gas connection pipe 6 is divided and flows into the indoor switching units 4a to 4c. In each indoor switching unit 4a-4c, since both the indoor first on-off valves 41a-41c and the indoor second on-off valves 42a-42c are open, the gas refrigerant flowing through the first main gas connection pipe 5 The gas refrigerant that has passed through the first on-off valves 41a to 41c and has flowed through the second main gas connection pipe 6 passes through the indoor second on-off valves 42a to 42c and merges with the indoor gas connection pipes 34a to 34c to each indoor unit 3a. To 3c. The gas refrigerant that has flowed into the indoor units 3a to 3c flows into the indoor heat exchangers 31a to 31c, and exchanges heat with the air that flows into the indoor heat exchangers 31a to 31c, thereby condensing the indoor heat exchangers 31a to 31c. The indoor side can be heated by releasing heat to the air. The liquid refrigerant condensed in the indoor heat exchangers 31a to 31c passes through the indoor expansion valves 32a to 32c, flows into the indoor liquid connection pipes 33a to 33c, joins, and is supplied to the main liquid connection pipe 7. The liquid refrigerant supplied to the main liquid connection pipe 7 is diverted, passes through the outdoor liquid connection pipes 18a and 18b of the outdoor units 1a and 1b, and is supplied to the outdoor units 1a and 1b. The liquid refrigerant supplied to the outdoor units 1a and 1b passes through the liquid blocking valves 15a and 15b, is depressurized by the outdoor expansion valves 14a and 14b, becomes low temperature and low pressure, and flows into the outdoor heat exchangers 13a and 13b. In the outdoor heat exchangers 13a and 13b, an endothermic cycle is formed by causing the outdoor heat exchangers 13a and 13b to function as an evaporator by exchanging heat with the inflowing air. Then, the evaporated refrigerant flows into the accumulators 17a and 17b via the four-way valves 12a and 12b, and the refrigerant is led to the suction side of the compressors 10a and 10b and compressed again to form a refrigeration cycle.

  As described above, all the indoor units perform the heating operation by replacing the outdoor flow path check valve of the outdoor switching unit with the open / close valve and changing the control of the indoor second open / close valve of the indoor switch unit. Even when the high pressure refrigerant discharged from the compressor passes through both the first main gas connection pipe and the second main gas connection pipe, the pressure loss up to the indoor unit is reduced by half, and the connection pipe is It is possible to halve the degree of decrease in the heating capacity that occurs when the length becomes longer than in the conventional refrigeration cycle. In this embodiment, the indoor units are activated one by one, but all the indoor units may be activated all at once. Even if only some indoor units are heated and there are indoor units that do not start, if the connection pipe is long with a large refrigeration cycle device, the pressure loss on the high-pressure side is reduced by half, and the heating operation is performed. The operating efficiency of the refrigeration cycle at the time can be improved. Moreover, also when the indoor unit in operation performs the cooling operation, the same effect can be exhibited by performing the same operation as that described in the first embodiment.

DESCRIPTION OF SYMBOLS 1a Outdoor unit 1 unit 1b Outdoor unit 2 unit 2a, 2b Outdoor switching unit 3a Indoor unit 1 unit 3b Indoor unit 2 unit 3c Indoor unit 3 units 4a-4c Indoor switching unit 5 1st main gas connection pipe (gas connection pipe)
6 Second main gas connection pipe (gas connection pipe)
7 Main liquid connection pipe (liquid connection pipe)
10a, 10b Compressor 11a, 11b Backflow prevention valve 12a, 12b Four-way valve 13a, 13b Outdoor heat exchanger 14a, 14b Outdoor expansion valve 15a, 15b Liquid blocking valve 16a, 16b Gas blocking valve 17a, 17b Accumulator 18a, 18b Outdoor liquid Connection pipe (liquid connection pipe)
19a, 19b Outdoor gas connection pipe (gas connection pipe)
21a, 21b Outdoor first on-off valves 22a, 22b Outdoor flow check valves 23a, 23b Outdoor second on-off valves 31a-31c Indoor heat exchangers 32a-32c Indoor expansion valves 33a-33c Indoor liquid connection pipes (liquid connection pipes)
34a-34c indoor gas connection pipe (gas connection pipe)
41a-41c indoor first on-off valve 42a-42c indoor second on-off valve

Claims (5)

A plurality of outdoor units having a compressor, a four-way valve, an outdoor heat exchanger, an outdoor pressure reducing device, a plurality of indoor units having an indoor pressure reducing device and an indoor heat exchanger, the plurality of outdoor units, and the plurality of units In the refrigeration cycle apparatus comprising a gas connection pipe and a liquid connection pipe connecting the indoor units in parallel, the plurality of indoor units can be operated simultaneously with cooling and heating,
The gas connection pipe branches and merges between the outdoor unit and the indoor unit into a first main gas connection pipe and a second main gas connection pipe, and the first main gas connection pipe and the indoor unit A first indoor open / close valve capable of opening and closing the flow path between the second main gas connection pipe and the indoor unit, a second indoor open / close valve capable of opening and closing the flow path, and the first main gas connection. A first outdoor on-off valve capable of opening and closing a flow path between a pipe and the outdoor unit; and the second main gas connection pipe to the outdoor unit between the second main gas connection pipe and the outdoor unit. With an outdoor channel check valve that allows only flow,
When all the indoor units activated among the plurality of indoor units are in the cooling operation, the indoor first on-off valve and the indoor second on-off valve downstream of the activated indoor unit are opened, and the plurality of indoor units are opened. Among the outdoor units, the first on-off valve on the upstream side of the outdoor unit where the compressor is activated is opened, the refrigerant coming out of the indoor unit branches, and the first main gas connection pipe and the second main gas A refrigeration cycle apparatus which flows through a connecting pipe and joins the outdoor unit after joining. In Claim 1, it has an outdoor second on-off valve capable of opening and closing the flow path instead of the outdoor flow path check valve,
Among the plurality of outdoor units, the outdoor first on-off valve and the outdoor second on-off valve upstream of the outdoor unit in which a compressor is activated are opened, and the refrigerant that has flowed out of the indoor unit branches off to form the first A refrigeration cycle apparatus that flows through a main gas connection pipe and a second main gas connection pipe and joins the outdoor unit after joining.   3. The refrigeration cycle apparatus according to claim 1, wherein the indoor first on-off valve provided in the indoor unit whose operation is stopped among the indoor units in the cooling operation is closed. A plurality of outdoor units having a compressor, a four-way valve, an outdoor heat exchanger, an outdoor pressure reducing device, a plurality of indoor units having an indoor pressure reducing device and an indoor heat exchanger, the plurality of outdoor units, and the plurality of units In the refrigeration cycle apparatus comprising a gas connection pipe and a liquid connection pipe connecting the indoor units in parallel, the plurality of indoor units can be operated simultaneously with cooling and heating,
The gas connection pipe branches and merges between the outdoor unit and the indoor unit into a first main gas connection pipe and a second main gas connection pipe, and the first main gas connection pipe and the indoor unit A first indoor open / close valve capable of opening and closing the flow path between the second main gas connection pipe and the indoor unit, a second indoor open / close valve capable of opening and closing the flow path, and the first main gas connection. An outdoor first on-off valve capable of opening and closing a flow path between a pipe and the outdoor unit, and an outdoor second on-off valve capable of opening and closing a flow path between the second main gas connection pipe and the outdoor unit. Prepared,
When all the activated indoor units among the plurality of indoor units are in the heating operation, the indoor first on-off valve and the indoor second on-off valve upstream of the activated indoor unit are opened, and the plurality of indoor units are opened. The outdoor first on-off valve and the outdoor second on-off valve downstream of the outdoor unit in which the compressor is activated among the outdoor units of the outdoor unit are opened, and the refrigerant discharged from the outdoor unit branches to the first main gas A refrigeration cycle apparatus which flows through a connecting pipe and the second main gas connecting pipe and joins the indoor unit after joining.   5. The refrigeration cycle apparatus according to claim 4, wherein the indoor first open / close valve and the indoor second open / close valve provided in the indoor unit whose operation is stopped among the indoor units in the heating operation are closed.

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