Outdoor unit for air conditioner, and air conditioner

Abstract

The invention provides an outdoor unit of an air conditioner and the air conditioner, which can be applied to any one of a heat recovery type and a multi-split type, and can suppress the retention of refrigerating machine oil in an outdoor pipe which is closed when the outdoor unit is applied to the multi-split type. The outdoor unit (5) is provided with: a seventh branch pipe (67) that connects the outdoor heat exchanger (13) and the indoor units (6A, 6B,...); a tenth pipe (70) which is one branch of the first switching valve (12A) and connects the compressor (2) and the indoor units (6A, 6B,...); and an eighth branch pipe (68A) connected to one branch of the first switching valve (12A) and connecting the compressor (2) and the indoor units (6A, 6B,...) by bypassing the first switching valve (12A). The eighth branch pipe (68A) is provided with: a main flow pipe section (85) through which the refrigerant sucked into the compressor (2) via the first switching valve (12A) flows; and an elbow pipe section (86) that intersects the main flow pipe section (85), branches off, and descends rearward and downward.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to an outdoor unit of an air conditioning apparatus and an air conditioning apparatus. BACKGROUND

[0002] There is known an air conditioning apparatus provided with an outdoor unit, a plurality of indoor units, a plurality of switching units, a first connection pipe, a second connection pipe, and a third connection pipe. The outdoor unit is provided with an outdoor heat exchanger and a compressor. The outdoor unit is provided with an outdoor first pipe connecting the outdoor heat exchanger with the first connection pipe, an outdoor second pipe connecting the compressor with the second connection pipe, and an outdoor third pipe connecting the compressor with the third connection pipe. Each of the indoor units is provided with an indoor heat exchanger.

[0003] Each of the switching units is provided with an indoor first pipe connecting the indoor heat exchanger with the first connection pipe, an indoor second pipe connecting the indoor heat exchanger with the second connection pipe, an indoor third pipe connecting the indoor heat exchanger with the third connection pipe, and an indoor third pipe valve provided in the indoor third pipe. Each of the indoor third pipe valves switches a connection state of the three pipes of the outdoor unit and the two pipes of each of the indoor units.

[0004] The existing air conditioning apparatus not only can perform a heating operation in all of the indoor units or perform a cooling operation in all of the indoor units, but also can perform a heating operation in a part of the indoor units and perform a cooling operation in the remaining part of the indoor units.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT DOCUMENTS

[0007] Patent Document 1: Japanese Patent Application Publication No. 2017-180882 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] The existing air conditioning apparatus is a so-called heat recovery type (heat recovery system, heat recovery system) multi-split air conditioning apparatus.

[0010] However, if the outdoor unit is directly connected with the plurality of indoor units by two connection pipes, for example, the first connection pipe and the second connection pipe, without passing through the switching unit, the existing air conditioning apparatus functions as a multi-split air conditioning apparatus that performs a heating operation in all of the indoor units or performs a cooling operation in all of the indoor units. In this case, one of the three outdoor pipes (the outdoor first pipe, the outdoor second pipe, and the outdoor third pipe), for example, the outdoor third pipe is not connected with the connection valve and is closed at the end.

[0011] This end-closed outdoor third pipe becomes a so-called dead leg. The pipe of the dead leg has a possibility of retaining refrigerant and refrigerant- containing refrigerant oil. If a large amount of refrigerant oil is retained in the dead leg, lubrication of the compressor can be insufficient.

[0012] Therefore, an object of the present application is to provide an outdoor unit of an air conditioning apparatus and an air conditioning apparatus which can be applied to either of a heat recovery type and a general multi-type, and which can suppress retention of refrigerant oil in an outdoor pipe closed when applied to the multi-type.

[0013] Means for solving the problem

[0014] To solve the above problem, an outdoor unit of an air conditioning apparatus of an embodiment of the present application includes: a compressor that compresses refrigerant; an outdoor heat exchanger that exchanges heat between the refrigerant and outside air; a first switching valve that can either cut off connection of a discharge side of the compressor with indoor heat exchangers of all indoor units to cause the outdoor heat exchanger to function as a condenser, or connect the discharge side of the compressor with the indoor heat exchanger of at least one of the indoor units to cause the indoor heat exchanger of the at least one of the indoor units to function as a condenser; a second switching valve that can either connect a discharge side of the compressor with the outdoor heat exchanger to cause the outdoor heat exchanger to function as a condenser, or connect a suction side of the compressor with the outdoor heat exchanger to cause the outdoor heat exchanger to function as an evaporator; an outdoor first pipe that connects the outdoor heat exchanger with the indoor units; an outdoor second pipe that is one of branches of the first switching valve, and that connects the compressor with the indoor units; and an outdoor third pipe that is connected with one of the branches of the first switching valve, and that connects the compressor with the indoor units bypassing the first switching valve, the outdoor third pipe including: a main flow pipe portion through which the refrigerant sucked into the compressor via the first switching valve flows; and an elbow pipe portion that branches from the main flow pipe portion crossing the main flow pipe portion, and that descends rearward and downward.

[0015] Further, in order to solve the above problems, an outdoor unit of an air conditioning apparatus according to an embodiment of the present application has: a compressor that compresses a refrigerant; an outdoor heat exchanger that exchanges heat between the refrigerant and outside air; a first switching valve that can either cut off a connection between a discharge side of the compressor and indoor heat exchangers of all indoor units to cause the outdoor heat exchanger to function as a condenser, or connect the discharge side of the compressor and the indoor heat exchanger of at least one of the indoor units to cause the indoor heat exchanger of the at least one of the indoor units to function as a condenser; a second switching valve that can either connect a discharge side of the compressor and the outdoor heat exchanger to cause the outdoor heat exchanger to function as a condenser, or connect a suction side of the compressor and the outdoor heat exchanger to cause the outdoor heat exchanger to function as an evaporator; an outdoor first pipe that connects the outdoor heat exchanger and the indoor units; an outdoor second pipe that is one of branches of the first switching valve, and connects the compressor and the indoor units; and an outdoor third pipe that is connected to one of the branches of the first switching valve, and is connected to the compressor, wherein, in a case where the outdoor first pipe, the outdoor second pipe, and the outdoor third pipe are connected to the indoor units via a plurality of switching units that can switch a flow direction of the refrigerant flowing in the indoor units, the outdoor third pipe connects the compressor and the indoor units bypassing the first switching valve, and in a case where the outdoor first pipe and the outdoor second pipe are connected to the indoor units without passing through the plurality of switching units, the outdoor third pipe has: a main flow pipe portion through which the refrigerant sucked into the compressor via the first switching valve flows; and an elbow pipe portion that branches from the main flow pipe portion and descends downward to the rear.

[0016] Further, preferably, the main flow pipe portion of the outdoor unit of the air conditioning apparatus according to the embodiment of the present application has a straight pipe portion that extends downward vertically from a branching portion of the main flow pipe portion and the elbow pipe portion, to cause a liquid component contained in the refrigerant to flow downward vertically.

[0017] Further, preferably, the outdoor unit of the air conditioning apparatus according to the embodiment of the present application has a recovery pipe that connects the outdoor third pipe and a suction side of the compressor.

[0018] Further, in order to solve the above problems, an air conditioning apparatus according to an embodiment of the present application includes: the outdoor unit; and a plurality of indoor units that exchange heat between the refrigerant and air in a room, the outdoor unit having an outdoor expansion valve connected to the discharge side of the outdoor heat exchanger, each of the indoor units having an indoor heat exchanger and an indoor expansion valve connected to the outdoor heat exchanger, in a case where a plurality of switching units that can switch the flow direction of the refrigerant flowing in the corresponding indoor unit are provided, the flow direction of the refrigerant flowing in the plurality of indoor units can be made different from each other to exist mixedly between the indoor unit performing a cooling operation and the indoor unit performing a heating operation, in a case where the plurality of switching units are not provided, the flow direction of the refrigerant flowing in the plurality of indoor units is made uniform to make all of the indoor units perform a cooling operation or a heating operation in a manner that the refrigerant is sucked into the compressor through the first switching valve at the time of a cooling operation and the refrigerant is delivered to the plurality of indoor units through the first switching valve at the time of a heating operation.

[0019] Effects of Invention

[0020] According to the present application, an outdoor unit of an air conditioning apparatus and an air conditioning apparatus can be applied to either of a heat recovery type and a general multi-type, and can suppress the stagnation of refrigerant oil in an outdoor pipe that is closed when applied to the multi-type. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a block diagram of an air conditioning apparatus according to an embodiment of the present application.

[0022] Figure 2 is a diagram showing an example of the flow of refrigerant in a cooling mixed operation state of an air conditioning apparatus according to an embodiment of the present application.

[0023] Figure 3 is a diagram showing another example of the flow of refrigerant in a cooling mixed operation state of an air conditioning apparatus according to an embodiment of the present application.

[0024] Figure 4 is a diagram showing an example of the flow of refrigerant in a heating mixed operation state of an air conditioning apparatus according to an embodiment of the present application.

[0025] Figure 5 is a block diagram of a second mode of an air conditioning apparatus according to an embodiment of the present application.

[0026] Figure 6 is a diagram showing an example of the flow of refrigerant in a cooling mixed operation state of an air conditioning apparatus according to an embodiment of the present application.

[0027] Figure 7is a schematic view of a first example of an eighth branch pipe of an outdoor unit of an embodiment of the present application.

[0028] Figure 8 is a schematic view of a second example of an eighth branch pipe of an outdoor unit of an embodiment of the present application.

[0029] Figure 9 is a schematic view of a third example of an eighth branch pipe of an outdoor unit of an embodiment of the present application.

[0030] Figure 10 is a schematic view of a fourth example of an eighth branch pipe of an outdoor unit of an embodiment of the present application.

[0031] Figure 11 is a block diagram of a third mode of an air-conditioning apparatus of an embodiment of the present application. DETAILED DESCRIPTION

[0032] REFERENCE Figures 1 to 11 Embodiments of an air-conditioning apparatus of the present application and embodiments of an outdoor unit of the air-conditioning apparatus are described. In addition, the same reference characters are assigned to the same or equivalent structures in the plurality of drawings.

[0033] Figure 1 is a block diagram of an air-conditioning apparatus of an embodiment of the present application.

[0034] As Figure 1 shown, the air-conditioning apparatus 1 of the present embodiment is a multi-connected air-conditioning apparatus of a heat recovery type (heat recovery mode, heat-recovery mode). The air-conditioning apparatus 1 is provided with at least one outdoor unit 5 having a compressor 2 that compresses a refrigerant, a plurality of indoor units 6A, 6B, …, and a plurality of switching units 7A, 7B, … that can respectively switch the flow direction of the refrigerant flowing in the indoor units 6A, 6B, …. In addition, the air-conditioning apparatus 1 is provided with a refrigerant pipe 8 that circulates the refrigerant while sequentially connecting the outdoor unit 5, the plurality of switching units 7A, 7B, …, and the plurality of indoor units 6A, 6B, …

[0035] The air-conditioning apparatus 1 performs a full refrigeration operation in which the refrigerant is circulated between the outdoor unit 5 and the plurality of indoor units 6A, 6B, …, the outdoor unit 5 functions as a condenser, and all of the indoor units 6A, 6B, … function as evaporators, and a full heating operation in which the outdoor unit 5 functions as an evaporator and all of the indoor units 6A, 6B, … function as condensers.

[0036] Further, the air conditioning apparatus 1 can cause the indoor units 6A, 6B,... in which the refrigerant flows to exist in a mixed manner in which the indoor units 6A, 6B,... that perform the cooling operation and the indoor units 6A, 6B,... that perform the heating operation are different from each other in the flow direction of the refrigerant. The air conditioning apparatus 1 performs a cooling mixed operation in which the outdoor unit 5 functions as a condenser, a part of the indoor units 6A, 6B function as evaporators, and the remaining indoor units 6C function as condensers, and a heating mixed operation in which the outdoor unit 5 functions as an evaporator, a part of the indoor units 6A, 6B function as condensers, and the remaining indoor units 6C function as evaporators. The cooling mixed operation is an operation of a cooling main body in which a plurality of indoor units 6A, 6B perform the cooling operation and a small number of indoor units 6C perform the heating operation. The heating mixed operation is an operation of a heating main body in which a plurality of indoor units 6A, 6B perform the heating operation and a small number of indoor units 6C perform the cooling operation.

[0037] The outdoor unit 5 includes a compressor 2 that compresses and discharges the refrigerant taken in, an oil separator 11 provided on the discharge side of the compressor 2, at least three switching valves 12A, 12B, 12C that switch the circulation path of the refrigerant circulating between the outdoor unit 5 and the indoor units 6A, 6B,..., two outdoor heat exchangers 13 that cause the refrigerant to exchange heat with outside air, two outdoor expansion valves 15 that decompress the refrigerant flowing from the indoor units 6A, 6B,... to each of the outdoor heat exchangers 13, and a liquid reservoir 16 provided on the suction side of the compressor 2. In addition, the outdoor unit 5 includes an outdoor fan 17 that causes the outside air that exchanges heat at the two outdoor heat exchangers 13 to flow. Furthermore, the outdoor unit 5 includes an inverter circuit 18 that controls the operation frequency of the compressor 2 and a control portion 19 that controls the inverter circuit 18.

[0038] The plurality of indoor units 6A, 6B,... have the same structure. Hereinafter, a representative one of the indoor units 6A will be described. The indoor unit 6A includes an indoor heat exchanger 21A that causes the refrigerant to exchange heat with indoor air and an indoor expansion valve 22A that decompresses the refrigerant flowing from the outdoor unit 5 to the indoor heat exchanger 21A. In addition, the indoor unit 6A includes an indoor fan 23A that causes the indoor air that exchanges heat at the indoor heat exchanger 21A to flow. Furthermore, the indoor unit 6A includes an indoor control portion (not shown).

[0039] The plurality of switching units 7A, 7B,... have the same structure. Hereinafter, a representative one of the switching units 7A will be described. The switching unit 7A is provided with an outlet gas pipe shutoff valve 25A that allows or shuts off the flow of refrigerant from the compressor 2 toward the indoor heat exchanger 21A, and an intake gas pipe shutoff valve 26A that allows or shuts off the flow of refrigerant from the indoor heat exchanger 21A toward the compressor 2. By closing the outlet gas pipe shutoff valve 25A and opening the intake gas pipe shutoff valve 26A, the indoor heat exchanger 21A of the indoor unit 6A functions as an evaporator. By opening the outlet gas pipe shutoff valve 25A and closing the intake gas pipe shutoff valve 26A, the indoor heat exchanger 21A functions as a condenser.

[0040] The compressor 2 is housed in the outdoor unit 5. The compressor 2 changes the operation frequency by the output of the inverter circuit 18. The air conditioning apparatus 1 can also be provided with a plurality of compressors 2. In this case, it is preferable that the number of inverter circuits 18 be the same as the number of compressors 2, and each inverter circuit 18 control the operation frequency of the corresponding compressor 2. The compressor 2 changes the operation frequency by a known inverter control. The compressor 2 can also operate at a constant operation frequency.

[0041] The compressor 2 is provided with a hermetic case, a compression mechanism that compresses refrigerant, and a motor that drives the compression mechanism. The hermetic case houses the compression mechanism and the motor. The hermetic case stores refrigeration oil that lubricates the compression mechanism. The discharge side of the compressor 2 is connected to the oil separator 11. The suction side of the compressor 2 is connected to the accumulator 16. In addition, the compressor 2 is provided with an accumulator 2a that is smaller in capacity than the accumulator 16. This small-capacity accumulator 2a is a gas-liquid separator that separates gaseous refrigerant from liquid refrigerant and delivers the gaseous refrigerant to the compressor 2. The small-capacity accumulator 2a is also called a suction muffler or a suction cup, and is provided between the suction side of the compressor 2 and the large-capacity accumulator 16.

[0042] The oil separator 11 separates gaseous refrigerant discharged from the compressor 2 from refrigeration oil. The refrigeration oil separated by the oil separator 11 is returned to the compressor 2 by a return pipe (omitted from the drawing). The oil separator 11 is, for example, a centrifugal separation type separator.

[0043] The two outdoor heat exchangers 13 and the indoor heat exchanger 21A are, for example, fin-and-tube type heat exchangers. The two outdoor heat exchangers 13 and the indoor heat exchanger 21A are provided with a plurality of passages 28 through which refrigerant flows, a header 29 that distributes refrigerant to the plurality of passages 28 or merges refrigerant distributed to the plurality of passages 28, and a plurality of fins (omitted from the drawing) that extend orthogonally to the plurality of passages 28.

[0044] The two outdoor heat exchangers 13 include a main heat exchanger 31a as an outdoor first heat exchanger and a sub heat exchanger 31b as an outdoor second heat exchanger connected in parallel with the main heat exchanger 31a. The main heat exchanger 31a is connected to the second switching valve 12B. The sub heat exchanger 31b is connected to the third switching valve 12C.

[0045] Each of the switching valves 12A, 12B, 12C is electrically connected to the control unit 19 through a signal line (not shown). The air conditioning apparatus 1 switches between a cooling operation (flow of refrigerant shown by solid arrows) and a heating operation (flow of refrigerant shown by dashed arrows) by switching the flow direction of the refrigerant using the three switching valves 12A, 12B, 12C. Figure 1 Figure 1

[0046] The second switching valve 12B connects the discharge side of the compressor 2 to the main heat exchanger 31a to function as a condenser. In addition, the second switching valve 12B connects the suction side of the compressor 2 to the main heat exchanger 31a to function as an evaporator.

[0047] The third switching valve 12C connects the discharge side of the compressor 2 to the sub heat exchanger 31b to function as a condenser. In addition, the third switching valve 12C connects the suction side of the compressor 2 to the sub heat exchanger 31b to function as an evaporator.

[0048] The first switching valve 12A disconnects the discharge side of the compressor 2 from the indoor heat exchangers 21A, 21B,... of all the indoor units 6A, 6B,..., causes the two outdoor heat exchangers 13 to function as condensers, or connects the discharge side of the compressor 2 to the indoor heat exchanger 21A, 21B,... of at least one of the indoor units 6A, 6B,..., causes the indoor heat exchanger 21A, 21B,... of at least one of the indoor units 6A, 6B,... to function as a condenser.

[0049] The two outdoor expansion valves 15 are a first outdoor expansion valve 15a connected to the main heat exchanger 31a and a second outdoor expansion valve 15b connected to the sub heat exchanger 31b.

[0050] The main heat exchanger 31a is disposed between the second switching valve 12B and the first outdoor expansion valve 15a, and the sub heat exchanger 31b is disposed between the third switching valve 12C and the second outdoor expansion valve 15b. That is, the refrigerant is distributed at the inlet side of the main heat exchanger 31a and the sub heat exchanger 31b, and is combined at the outlet side of the main heat exchanger 31a and the sub heat exchanger 31b.

[0051] ​​The outdoor fan 17 and the indoor fan 23A are, for example, axial fans. The outdoor fan 17 promotes heat exchange of outside air with refrigerant flowing in the two outdoor heat exchangers 13. The indoor fan 23A promotes heat exchange of indoor air with refrigerant flowing in the indoor heat exchanger 21A.

[0052] The two outdoor expansion valves 15 and the indoor expansion valve 22A are, for example, electronic expansion valves (Pulse Motor Valve, PMV) capable of adjusting the valve opening degree. The electronic expansion valve has a valve box having a through-hole, and a needle as a valve core capable of advancing and retreating with respect to the through-hole. When the needle clogs the through-hole, the electronic expansion valve cuts off the flow of refrigerant. At this time, the electronic expansion valve is in a closed state, and the valve opening degree of the electronic expansion valve is the smallest. When the needle is farthest from the through-hole, the electronic expansion valve maximizes the flow rate of refrigerant. At this time, the electronic expansion valve is in a fully open state, and the valve opening degree of the electronic expansion valve is the largest.

[0053] The accumulator 16 is a gas-liquid separator that separates gaseous refrigerant from liquid refrigerant and delivers gaseous refrigerant to the compressor 2.

[0054] The discharge gas pipe cut valve 25A and the suction gas pipe cut valve 26A can be on-off valves, or electronic expansion valves capable of adjusting the opening degree. The discharge gas pipe cut valve 25A allows or cuts off the flow of refrigerant discharged from the compressor 2 and discharged to the indoor heat exchanger 21A through the first switching valve 12A. The suction gas pipe cut valve 26A allows or cuts off the flow of refrigerant sucked from the indoor heat exchanger 21A to the compressor 2.

[0055] The refrigerant pipe 8 includes three connection pipes 35, 36, 37 that connect the outdoor unit 5 and the plurality of switching units 7A, 7B,... to and from which refrigerant passes, and two connection pipes 38A, 39A that connect the switching unit 7A and the indoor unit 6A to and from which refrigerant passes. The connection pipes 35, 36, 37 are branch pipes that connect one outdoor unit 5 and a plurality of switching units 7A, 7B,...

[0056] The outdoor unit 5 is provided with a pipe connection portion 41 that connects the connection pipe 35, a pipe connection portion 42 that connects the connection pipe 36, and a pipe connection portion 43 that connects the connection pipe 37.

[0057] The switching unit 7A is provided with a pipe connection portion 45A that connects the connection pipe 35, a pipe connection portion 46A that connects the connection pipe 36, and a pipe connection portion 47A that connects the connection pipe 37.

[0058] The connection pipe 35 is a branch pipe that connects one of the pipe connection portions 41 and a plurality of the pipe connection portions 45A, 45B,.... The connection pipe 36 is a branch pipe that connects one of the pipe connection portions 42 and a plurality of the pipe connection portions 46A, 46B,.... The connection pipe 37 is a branch pipe that connects one of the pipe connection portions 43 and a plurality of the pipe connection portions 47A, 47B,....

[0059] In addition, the switching unit 7A has a pipe connection portion 48A that connects the connection pipe 38A and a pipe connection portion 49A that connects the connection pipe 39A.

[0060] The indoor unit 6A has a pipe connection portion 51A that connects the connection pipe 38A and a pipe connection portion 52A that connects the connection pipe 39A.

[0061] The pipe connection portions 41, 42, 43 of the outdoor unit 5, the outdoor unit 5 side pipe connection portions 45A, 45B, 45C of each of the switching units 7A, 7B,..., the indoor unit 6A, 6B,... side pipe connection portions 48A, 48B, 48C, 49A, 49B, 49C of each of the switching units 7A, 7B,..., and the pipe connection portions 51A, 51B, 51C, 52A, 52B, 52C of the indoor units 6A, 6B,... are packed valves (back seating type valves) having a configuration that prevents leakage of refrigerant to the atmosphere.

[0062] The refrigerant pipe 8 connects the compressor 2, the oil separator 11, the three switching valves 12A, 12B, 12C, the two outdoor heat exchangers 13, the two outdoor expansion valves 15, the plurality of indoor expansion valves 22A, 22B,..., the plurality of indoor heat exchangers 21A, 21B,..., the plurality of discharge gas pipe cut valves 25A, 25B,..., the plurality of suction gas pipe cut valves 26A, 26B,..., and the accumulator 16 in this order.

[0063] The refrigerant pipe 8 in the outdoor unit 5 includes a first pipe 61 that connects the discharge side of the compressor 2 and the oil separator 11, a second branch pipe 62 that connects the oil separator 11 and the three switching valves 12A, 12B, 12C, a third pipe 63 that connects the second switching valve 12B and one of the outdoor heat exchangers 13, a fourth pipe 64 that connects the third switching valve 12C and the other of the outdoor heat exchangers 13, a fifth pipe 65 that connects one of the outdoor heat exchangers 13 and one of the outdoor expansion valves 15, a sixth pipe 66 that connects the other of the outdoor heat exchangers 13 and the other of the outdoor expansion valves 15, and a seventh branch pipe 67 that connects the two outdoor expansion valves 15 and the pipe connection portion 41.

[0064] The first pipe 61 and the second branch pipe 62 are pipes for transporting refrigerant connected to the discharge side of the compressor 2 regardless of the switching state of the three switching valves 12A, 12B, 12C.

[0065] In addition, the refrigerant pipe 8 in the outdoor unit 5 includes an eighth branch pipe 68 connecting the pipe connection portion 43, the three switching valves 12A, 12B, 12C, and the accumulator 16, a ninth pipe 69 connecting the accumulator 16 and the suction side of the compressor 2, and a tenth pipe 70 connecting the first switching valve 12A and the pipe connection portion 42.

[0066] The eighth branch pipe 68 and the ninth pipe 69 are pipes for returning refrigerant connected to the suction side of the compressor 2 regardless of the switching state of the three switching valves 12A, 12B, 12C.

[0067] The refrigerant pipe 8 in the switching unit 7A includes an eleventh pipe 71A connecting the pipe connection portion 45A and the pipe connection portion 48A, a twelfth branch pipe 72A connecting the discharge gas pipe shutoff valve 25A, the suction gas pipe shutoff valve 26A, and the pipe connection portion 49A, a thirteenth pipe 73A connecting the pipe connection portion 46A and the discharge gas pipe shutoff valve 25A, and a fourteenth pipe 74A connecting the pipe connection portion 47A and the suction gas pipe shutoff valve 26A.

[0068] The refrigerant pipe 8 in the indoor unit 6A includes a fifteenth pipe 75A connecting the pipe connection portion 51A and the indoor expansion valve 22A, a sixteenth pipe 76A connecting the indoor expansion valve 22A and the indoor heat exchanger 21A, and a seventeenth pipe 77A connecting the indoor heat exchanger 21A and the pipe connection portion 52A.

[0069] The inverter circuit 18 rectifies the alternating-current power supplied from the commercial alternating-current power supply E, converts the rectified direct-current power to a frequency corresponding to the instruction of the control portion 19, and outputs to the motor of the compressor 2. That is, the inverter circuit 18 can control the operation frequency of the compressor 2.

[0070] The control portion 19 controls the inverter circuit 18 to control the operation frequency of the compressor 2. In addition, the control portion 19 controls the three switching valves 12A, 12B, 12C, the plurality of discharge gas pipe shutoff valves 25A, 25B,..., and the plurality of suction gas pipe shutoff valves 26A, 26B,..., in accordance with the operation input to the remote controller (omitted from the drawing), switches the full refrigeration operation (flow of refrigerant indicated by the solid arrow) and the full heating operation (flow of refrigerant indicated by the dashed arrow) of the air conditioning device 1, and controls the operation of the compressor 2. Figure 1 Figure 1 ​The control section 19 controls the switching of the switching valves 12A, 12B, 12C, the opening and closing of the discharge gas pipe shut-off valves 25A, 25B,..., and the opening and closing of the suction gas pipe shut-off valves 26A, 26B,... (see the flow of the refrigerant indicated by the dotted arrows). In addition, the control section 19 can be provided separately in the outdoor unit 5 and the indoor units 6A, 6B,.... For example, the control section 19 of the outdoor unit 5 controls the inverter circuit 18 and the three switching valves 12A, 12B, 12C, and the control section 19 of each of the indoor units 6A, 6B,... controls the corresponding discharge gas pipe shut-off valves 25A, 25B,... and suction gas pipe shut-off valves 26A, 26B,....

[0071] Here, the operation states of the air conditioning apparatus 1 are described. In any operation, the compressor 2 discharges the refrigerant to the first pipe 61 and the second branch pipe 62, and sucks the refrigerant from the eighth branch pipe 68 and the ninth pipe 69.

[0072] Figure 1 The flow direction of the refrigerant in the full refrigeration operation is indicated by solid arrows. The second switching valve 12B and the third switching valve 12C are switched to connect the discharge side of the compressor 2 to each of the outdoor heat exchangers 13 (31a, 31b). That is, the second branch pipe 62 is connected to the third pipe 63 and the fourth pipe 64. The first switching valve 12A is switched to shut off the connection between the discharge side of the compressor 2 and the tenth pipe 70. The discharge gas pipe shut-off valves 25A, 25B,... are fully closed. The suction gas pipe shut-off valves 26A, 26B,... are fully opened to connect the indoor heat exchangers 21A, 21B,... to the suction side of the compressor 2.

[0073] The compressor 2 discharges high-temperature and high-pressure gas refrigerant to the first pipe 61. The high-temperature and high-pressure gas refrigerant flows from the first pipe 61 into the oil separator 11. The oil separator 11 separates refrigeration oil from the high-temperature and high-pressure gas refrigerant. The gas refrigerant from which the oil has been separated flows out of the oil separator 11, passes through the second switching valve 12B and the third switching valve 12C, and reaches the two outdoor heat exchangers 13 (31a, 31b). The two outdoor heat exchangers 13 (31a, 31b) cause the outside air to exchange heat with the gas refrigerant to condense the refrigerant, and cause liquid refrigerant to flow out. The liquid refrigerant flowing out of the two outdoor heat exchangers 13 (31a, 31b) passes through the two outdoor expansion valves 15 (15a, 15b), the eleventh pipes 71A, 71B,..., in the respective switching units 7A, 7B,..., and the respective indoor expansion valves 22A, 22B,..., and reaches the respective indoor heat exchangers 21A, 21B,.... The two outdoor expansion valves 15 (15a, 15b) adjust the flow rate of the liquid refrigerant to adjust the degree of supercooling. The respective indoor expansion valves 22A, 22B,... decompress the liquid refrigerant to become low-pressure gas-liquid two-phase refrigerant. The respective indoor heat exchangers 21A, 21B,... cause the air in the room to exchange heat with the gas-liquid two-phase refrigerant to evaporate the refrigerant, and cause gas refrigerant to flow out. The gas refrigerant flowing out of the respective indoor heat exchangers 21A, 21B,... is sent back to the outdoor unit 5 through the suction gas pipe shutoff valves 26A, 26B,... of the respective switching units 7A, 7B,.... At this time, the discharge gas pipe shutoff valves 25A, 25B,... are fully closed to hinder the flow of refrigerant in the connection pipe 36. The gas refrigerant reaching the outdoor unit 5 is sucked into the accumulator 16 through the eighth branch pipe 68. The accumulator 16 separates a small amount of liquid refrigerant mixed in the gas refrigerant. The gas refrigerant from which the liquid component has been separated flows out of the accumulator 16, and is sucked into the compressor 2. The sucked gas refrigerant is compressed by the compressor 2, and is discharged from the compressor 2 again.

[0074] Next, the flow direction of refrigerant in the full-heating operation is indicated by dotted arrows in Figure 1 The refrigerant flows in substantially the opposite direction to that in the full-cooling operation. The first switching valve 12A is switched to connect the discharge side of the compressor 2 with the switching units 7A, 7B,.... That is, the second branch pipe 62 is connected with the tenth pipe 70. The discharge gas pipe shutoff valves 25A, 25B,... are fully opened to connect the discharge side of the compressor 2 with the indoor heat exchangers 21A, 21B,.... The suction gas pipe shutoff valves 26A, 26B,... are fully closed. The second switching valve 12B and the third switching valve 12C are switched to connect the two outdoor heat exchangers 13 (31a, 31b) with the suction side of the compressor 2.

[0075] The gas refrigerant from which the oil component is separated flows out from the oil separator 11, passes through the first switching valve 12A, and reaches each switching unit 7A, 7B,.... The gas refrigerant that has reached each switching unit 7A, 7B,... passes through each discharge gas pipe shutoff valve 25A, 25B,... and reaches each indoor heat exchanger 21A, 21B,.... At this time, the suction gas pipe shutoff valves 26A, 26B,... are fully closed. The indoor heat exchangers 21A, 21B,... cause the indoor air to exchange heat with the gas refrigerant to condense the refrigerant, and cause the liquid refrigerant to flow out. The liquid refrigerant that has flowed out from the indoor heat exchangers 21A, 21B,... passes through each indoor expansion valve 22A, 22B,..., the eleventh pipe 71A, 71B,... in each switching unit 7A, 7B,..., both of the outdoor expansion valves 15 (15a, 15b), and reaches both of the outdoor heat exchangers 13 (31a, 31b). The outdoor expansion valves 15 (15a, 15b) depressurize the liquid refrigerant to become low-pressure gas-liquid two-phase refrigerant. The outdoor heat exchangers 13 (31a, 31b) cause the outside air to exchange heat with the gas-liquid two-phase refrigerant to evaporate the refrigerant, and cause the gas refrigerant to flow out. The gas refrigerant that has flowed out from the outdoor heat exchangers 13 (31a, 31b) is sucked into the accumulator 16 through the second switching valve 12B and the third switching valve 12C.

[0076] Figure 2 FIG. 1 is a view that shows the flow of the refrigerant in the heating operation in the air-conditioning apparatus according to the embodiment of the present application.

[0077] Figure 2 FIG. 1 is a view that shows the flow of the refrigerant in the heating operation in the air-conditioning apparatus according to the embodiment of the present application. Figure 2 Figure 2

[0078] The control unit 19 controls the three switching valves 12A, 12B, 12C, the plurality of discharge gas pipe shutoff valves 25A, 25B,..., and the plurality of suction gas pipe shutoff valves 26A, 26B,... based on the operation input to the remote controller (not shown), and executes the first example of the refrigerant-mixing operation of the air-conditioning apparatus 1.

[0079] ​​In the case of the refrigeration hybrid operation of the first example, the second switching valve 12B and the third switching valve 12C are switched so as to connect the discharge side of the compressor 2 with the two outdoor heat exchangers 13 (31a, 31b). The first switching valve 12A is switched so as to connect the discharge side of the compressor 2 with the switching units 7A, 7B,.... That is, the discharge side of the compressor 2 is connected with the two outdoor heat exchangers 13 (31a, 31b) while also being connected with the switching units 7A, 7B,....

[0080] In the refrigeration hybrid operation of the first example, the switching state of the first switching valve 12A is different from that in the case of the full refrigeration operation, and the open / close state of the discharge gas pipe shutoff valve 25C and the suction gas pipe shutoff valve 26C connected with the indoor heat exchanger 21C in which the heating operation is performed is reversed.

[0081] The discharge gas pipe shutoff valves 25A, 25B connected with the indoor heat exchangers 21A, 21B in which the refrigeration operation is performed are fully closed, and the suction gas pipe shutoff valves 26A, 26B connected with the indoor heat exchangers 21A, 21B in which the refrigeration operation is performed are fully open. The indoor heat exchangers 21A, 21B are connected with the suction side of the compressor 2.

[0082] In addition, the discharge gas pipe shutoff valve 25C connected with the indoor heat exchanger 21C in which the heating operation is performed is fully open, and the suction gas pipe shutoff valve 26C connected with the indoor heat exchanger 21C in which the heating operation is performed is fully closed. The indoor heat exchanger 21C is connected with the discharge side of the compressor 2.

[0083] Regarding the flow of the refrigerant in the refrigeration hybrid operation of the first example, the difference from the flow of the refrigerant in the full refrigeration operation will be described. A part of the gaseous refrigerant from which the oil component is separated flows out from the oil separator 11, reaches the two outdoor heat exchangers 13 (31a, 31b) via the second switching valve 12B and the third switching valve 12C, and the remaining part reaches the discharge gas pipe shutoff valves 25A, 25B,... of the respective switching units 7A, 7B,... via the first switching valve 12A. The fully closed discharge gas pipe shutoff valves 25A, 25B shut off the flow of the refrigerant to the indoor units 6A, 6B, and the fully open discharge gas pipe shutoff valve 25C allows the flow of the refrigerant to the indoor unit 6C. The indoor heat exchanger 21C causes the air in the room to exchange heat with the gaseous refrigerant to condense the refrigerant, and causes the liquid refrigerant to flow out. The liquid refrigerant flowing out from the indoor heat exchanger 21C is merged with the refrigerant flowing into the other indoor heat exchangers 21A, 21B via the indoor expansion valve 22C, the eleventh pipe 71C in the switching unit 7C, and the connection pipe 35.

[0084] Figure 3 is a second example of a diagram showing the flow of the refrigerant in the refrigeration hybrid operation state of the air conditioning apparatus of the embodiment of the present application.

[0085] Figure 3 The case where the heating operation in which the indoor heat exchanger 21C functions as a condenser is performed while the refrigeration operation in which the sub heat exchanger 31b functions as a condenser and the indoor heat exchangers 21A, 21B function as evaporators is performed is illustrated. In Figure 3 The flow direction of the refrigerant of the refrigeration operation is indicated by a solid arrow in Figure 3 The flow direction of the refrigerant of the heating operation is indicated by a dashed arrow in

[0086] The control unit 19 controls the three switching valves 12A, 12B, 12C, the plurality of discharge gas pipe shutoff valves 25A, 25B,..., and the plurality of suction gas pipe shutoff valves 26A, 26B,... based on the operation input to the remote controller (omitted from illustration) to perform the second example of the refrigeration mixed operation of the air conditioning device 1.

[0087] In the case of the second example of the refrigeration mixed operation, the second switching valve 12B is switched to shutoff the main heat exchanger 31a from the discharge side of the compressor 2, and the third switching valve 12C connects the discharge side of the compressor 2 to the sub heat exchanger 31b.

[0088] The first switching valve 12A is switched to connect the discharge side of the compressor 2 to the plurality of switching units 7A, 7B,.... That is, the discharge side of the compressor 2 is connected to the sub heat exchanger 31b, and also connected to the switching units 7A, 7B,....

[0089] In the second example of the refrigeration mixed operation, the switching states of the second switching valve 12B and the first switching valve 12A are different from those in the case of the full refrigeration operation, the opening and closing states of the first outdoor expansion valve 15a are reversed, and the opening and closing states of the discharge gas pipe shutoff valve 25C and the suction gas pipe shutoff valve 26C connected to the indoor heat exchanger 21C in which the heating operation is performed are reversed.

[0090] The discharge gas pipe shutoff valves 25A, 25B connected to the indoor heat exchangers 21A, 21B in which the refrigeration operation is performed are fully closed, and the suction gas pipe shutoff valve 26C connected to the indoor heat exchangers 21A, 21B in which the refrigeration operation is performed is fully open. The indoor heat exchangers 21A, 21B are connected to the suction side of the compressor 2.

[0091] In addition, the discharge gas pipe shutoff valve 25C connected to the indoor heat exchanger 21C in which the heating operation is performed is fully open, and the suction gas pipe shutoff valve 26C connected to the indoor heat exchanger 21C in which the heating operation is performed is fully closed. The indoor heat exchanger 21C is connected to the discharge side of the compressor 2.

[0092] In the second example of the refrigeration mixed operation, the refrigerant flows substantially the same as in the first example of the refrigeration mixed operation, but the second switching valve 12B and the first outdoor expansion valve 15a shutoff the flow of the refrigerant to the main heat exchanger 31a.

[0093] Such second example of the refrigeration hybrid operation is an operation mode that is advantageous in a case where the outside air temperature is close to the target temperature, without requiring refrigeration capacity, compared to the first example of the refrigeration hybrid operation.

[0094] In addition, the outdoor unit 5 of the air conditioning device 1 that performs the first example of the refrigeration hybrid operation without performing the second example of the refrigeration hybrid operation can have at least one outdoor heat exchanger 13 and at least one outdoor expansion valve 15, and can not have the third switching valve 12C connected to the sub heat exchanger 31b.

[0095] Figure 4 is a drawing illustrating an example of the flow of refrigerant in the heating hybrid operation state of the air conditioning device of the embodiment of the present application.

[0096] Figure 4 The heating operation in which the two outdoor heat exchangers 13 (31a, 31b) function as evaporators, the indoor heat exchangers 21A, 21B function as condensers, and the refrigeration operation in which the indoor heat exchanger 21C functions as an evaporator are illustrated. Figure 4 The flow direction of the refrigerant in the refrigeration operation is indicated by solid arrows in Figure 4 The flow direction of the refrigerant in the heating operation is indicated by dashed arrows in

[0097] The control unit 19 controls the three switching valves 12A, 12B, 12C, the plurality of discharge gas pipe shutoff valves 25A, 25B,..., and the plurality of suction gas pipe shutoff valves 26A, 26B,... based on the operation input to the remote controller (omitted from illustration) to perform the heating hybrid operation of the air conditioning device 1.

[0098] The switching states of the three switching valves 12A, 12B, 12C in the heating hybrid operation are the same as the switching states of the three switching valves 12A, 12B, 12C in the full heating operation.

[0099] In the heating hybrid operation, the open / close states of the discharge gas pipe shutoff valve 25C and the suction gas pipe shutoff valve 26C connected to the indoor heat exchanger 21C in which the refrigeration operation is performed are reversed compared to the case of the full heating operation.

[0100] The discharge gas pipe shutoff valves 25A, 25B connected to the indoor heat exchangers 21A, 21B in which the heating operation is performed are fully open, and the suction gas pipe shutoff valves 26A, 26B connected to the indoor heat exchangers 21A, 21B in which the heating operation is performed are fully closed. That is, the indoor heat exchangers 21A, 21B are connected to the discharge side of the compressor 2.

[0101] Further, the discharge gas pipe shutoff valve 25C connected to the indoor heat exchanger 21C during the cooling operation is fully closed, and the suction gas pipe shutoff valve 26C connected to the indoor heat exchanger 21C during the cooling operation is fully open. That is, the indoor heat exchanger 21C is connected to the suction side of the compressor 2.

[0102] In the heating mixed operation, the refrigerant flows substantially the same as in the full heating operation, but the liquid refrigerant flowing out of the indoor heat exchangers 21A, 21B branches at the connection pipe 35, is depressurized at the indoor expansion valve 22C, and reaches the indoor heat exchanger 21C. The indoor heat exchanger 21C exchanges heat between the indoor air and the gas-liquid two-phase refrigerant to evaporate the refrigerant, and causes the gas refrigerant to flow out. The gas refrigerant flowing out of the indoor heat exchanger 21C is sucked into the accumulator 16 through the suction gas pipe shutoff valve 26C.

[0103] Figure 5 is a block diagram of a second mode of the air conditioning apparatus according to the embodiment of the present application.

[0104] As shown in Figure 5 , the air conditioning apparatus 1 according to the embodiment can not be provided with the plurality of switching units 7A, 7B,.... The connection pipe 35 connects one pipe connection portion 41 of the outdoor unit 5 to the respective pipe connection portions 51A, 51B,... of the plurality of indoor units 6A, 6B,.... The connection pipe 36 connects one pipe connection portion 42 of the outdoor unit 5 to the respective pipe connection portions 52A, 52B,... of the plurality of indoor units 6A, 6B,.... The pipe connection portion 43 is maintained in a closed state without the connection pipe 37. The first switching valve 12A of the outdoor unit 5 is switched so that the refrigerant is sucked from the plurality of indoor units 6A, 6B,... to the compressor 2 during the cooling operation, and the refrigerant is delivered from the compressor 2 to the plurality of indoor units 6A, 6B,... during the heating operation.

[0105] The air conditioning apparatus 1 can be provided with a seal plug 81 shown by a double-dot chain line in Figure 5 , which seals the pipe connection portion 43 of the outdoor unit 5.

[0106] That is, the air conditioning apparatus 1 can be used in a second mode in which the pipe connection portion 43 is plugged, the plurality of switching units 7A, 7B,... are not provided, and the outdoor unit 5 is directly connected to the plurality of indoor units 6A, 6B,... through the connection pipes 35, 36. Figure 5 The second mode of the air conditioning apparatus 1 performs the cooling operation by circulating the refrigerant in the direction shown by solid arrows in Figure 5 , and performs the heating by circulating the refrigerant in the direction shown by dashed arrows in

[0107] In a case where the air-conditioning apparatus 1 of the second embodiment performs the full-cooling operation, the second switching valve 12B is switched so as to connect the discharge side of the compressor 2 with the outdoor heat exchanger 13, and cut off the eighth branch pipe 68 (outdoor third pipe) from the discharge side of the compressor 2. The first switching valve 12A is switched so as to connect the tenth pipe 70 (outdoor second pipe) with the eighth branch pipe 68 on the suction side of the compressor 2.

[0108] In a case where the air-conditioning apparatus 1 of the second embodiment performs the full-cooling operation, the second switching valve 12B is switched so as to connect the discharge side of the compressor 2 with the outdoor heat exchanger 13, and cut off the eighth branch pipe 68 (outdoor third pipe) from the discharge side of the compressor 2. The first switching valve 12A is switched so as to connect the tenth pipe 70 (outdoor second pipe) with the eighth branch pipe 68 on the suction side of the compressor 2.

[0109] Therefore, when the pipe connection portion 43 of the outdoor unit 5 is closed, the air-conditioning apparatus 1 functions as a multi-type air-conditioning apparatus that performs the full-cooling operation or the full-heating operation.

[0110] In addition, with respect to Figures 1 to 5 , the outdoor heat exchanger 13 can be only one system. For example, the outdoor unit 5 can have only the main heat exchanger 31a. In this case, the third switching valve 12C, the sub heat exchanger 31b, and the second outdoor expansion valve 15b are not needed.

[0111] Figure 6 is a schematic view of a comparative example of the eighth branch pipe of the outdoor unit of the embodiment of the present application.

[0112] Figure 7 is a schematic view of a first example of the eighth branch pipe of the outdoor unit of the embodiment of the present application.

[0113] As shown in Figure 5 and Figure 6 , the comparative example of the eighth branch pipe 68 connects the three switching valves 12A, 12B, 12C with the accumulator 16 disposed on the suction side of the compressor 2, and connects the pipe connection portion 43 with the accumulator 16. That is, the eighth branch pipe 68 is the refrigerant pipe 8 that is connected with the suction side of the compressor 2 regardless of the operation state of the air-conditioning apparatus 1. The eighth branch pipe 68 has a branch portion D in which the pipes toward the first switching valve 12A, the accumulator 16, and the pipe connection portion 43 cross.

[0114] In the air-conditioning apparatus 1 of the second embodiment, the eighth branch pipe 68 is not connected with the connection pipe 37. In other words, the pipe between the branch portion D and the pipe connection portion 43 becomes a so-called dead end DE in the air-conditioning apparatus 1 of the second embodiment. This dead end DE can cause the refrigerant and the refrigeration oil mixed in the refrigerant to be trapped.

[0115] Further, regarding the flow of the refrigerant and the refrigerant oil mixed in the refrigerant in the eighth branch pipe 68, the flow of the refrigerant during the cooling operation is indicated by a hollow solid arrow, the flow of the refrigerant during the heating operation is indicated by a blackened arrow, and the flow of the refrigerant during the cooling operation and the heating operation is indicated by a hatched arrow. The refrigerant during the cooling operation flows from the first switching valve 12A into the eighth branch pipe 68, and the refrigerant during the heating operation flows from the second switching valve 12B and the third switching valve 12C into the eighth branch pipe 68. Further, the refrigerant and the refrigerant oil mixed in the refrigerant that stagnate in the dead end DE are indicated by a hatched region FS.

[0116] Therefore, as Figure 7 indicated, the eighth branch pipe 68A of the first example of the outdoor unit 5 of the present embodiment includes a main flow pipe portion 85 through which the refrigerant sucked into the compressor 2 via the first switching valve 12A in one switching state of the first switching valve 12A or the refrigerant sucked into the compressor 2 via the second switching valve 12B and the third switching valve 12C in one switching state of the second switching valve 12B and the third switching valve 12C flows, and an elbow portion 86 that branches upwardly across the main flow pipe portion 85 and then descends downwardly.

[0117] Further, in a case where the air conditioning device is caused to perform the cooling operation, the refrigerant is sucked into the compressor 2 via the first switching valve 12A. That is, one of the switching states of the first switching valve 12A in which the refrigerant sucked into the compressor 2 via the first switching valve 12A flows in the main flow pipe portion 85 corresponds to the switching state of the first switching valve 12A in the full cooling operation of the air conditioning device 1. Further, in a case where the air conditioning device is caused to perform the heating operation, the refrigerant is sucked into the compressor 2 via the second switching valve 12B and the third switching valve 12C. That is, one of the switching states of the first switching valve 12A in which the refrigerant sucked into the compressor 2 via the second switching valve 12B and the third switching valve 12C flows in the main flow pipe portion 85 corresponds to the switching state of the second switching valve 12B and the third switching valve 12C in the full heating operation of the air conditioning device 1.

[0118] The main flow pipe portion 85 has an upstream straight pipe portion 85u that feeds the refrigerant from the three switching valves 12A, 12B, 12C to the branch portion D.

[0119] Further, the main flow pipe portion 85 has a downstream straight pipe portion 85d that extends from the branch portion D of the main flow pipe portion 85 and the elbow portion 86 to the vertically downward direction so as to cause the liquid component included in the refrigerant to flow down in the vertically downward direction. The downstream straight pipe portion 85d is a portion of the eighth branch pipe 68A that connects the branch portion D and the accumulator 16.

[0120] The curved pipe portion 86 includes a straight pipe portion 86a extending vertically upward from the branch portion D. The straight pipe portion 86a is a portion of the eighth branch pipe 68A connecting the branch portion D and the piping connection portion 43, and is connected to the curved portion 86b at a location away from the branch portion D. The eighth branch pipe 68A, which is located in front of the curved portion 86b, preferably extends further downward, reaching the piping connection portion 43 at a location below the upstream straight pipe portion 85u of the main pipe portion 85. The portion of the eighth branch pipe 68A connecting the branch portion D and the piping connection portion 43 forms a dead end DE. In other words, the straight pipe portion 86a, the curved portion 86b, and the portion of the eighth branch pipe 68A connecting the curved portion 86b and the piping connection portion 43 form a dead end DE.

[0121] The upstream straight pipe portion 85u and the straight pipe portion 86a of the curved pipe portion 86 preferably branch and intersect at an angle θ1 of 90 degrees or less. The upstream straight pipe portion 85u and the downstream straight pipe portion 85d preferably branch and intersect at an angle θ2 of 90 degrees or greater. Furthermore, the downstream straight pipe portion 85d and the straight pipe portion 86a of the curved pipe portion 86 are preferably continuous straight pipes. As an example, the shape of the branch portion D is a horizontal T-shape formed by the downstream straight pipe portion 85d and the straight pipe portion 86a of the curved pipe portion 86 extending vertically as continuous straight pipes, and the upstream straight pipe portion 85u abutting against these straight pipes from a horizontal direction.

[0122] During cooling operation, Figure 7 The refrigerant flowing through the eighth branch pipe 68A shown here flows in through the first switching valve 12A, reaches the branch portion D from the upstream straight pipe section 85u, and is then drawn into the downstream straight pipe section 85d by gravity and the suction pressure of the compressor 2, flowing downward. Similarly, during heating operation, the refrigerant flowing through the eighth branch pipe 68A flows in through the second switching valve 12B and the third switching valve 12C, reaches the branch portion D from the upstream straight pipe section 85u, and is then drawn into the downstream straight pipe section 85d by gravity and the suction pressure of the compressor 2, flowing downward. Furthermore, the refrigerant reaching the branch portion D from the upstream straight pipe section 85u stagnates upon impact with the inner wall surfaces of the downstream straight pipe section 85d and the straight pipe section 86a of the curved pipe section 86, decelerating. Then, due to gravity and the suction pressure of the compressor 2, it is drawn into the downstream straight pipe section 85d and flows downward. At this time, a small amount of refrigerant wants to go upward at the branch portion D, but is blocked by the curved pipe portion 86 having a straight pipe portion 86a extending upward, and the front end of the curved pipe portion 86 is a dead end DE, thereby reducing the possibility of the refrigerant and refrigeration oil being retained in the dead end DE.

[0123] Figure 8 This is a schematic diagram of a second example of the eighth branch pipe of the outdoor unit according to the embodiment of the present invention.

[0124] like Figure 8As shown, in the eighth branch pipe 68B of the first example of the outdoor unit 5 of the present embodiment, the upstream straight pipe portion 85u and the downstream straight pipe portion 85d of the main flow pipe portion 85 are continuously provided in a straight pipe shape vertically downward, and the elbow pipe portion 86 branches from the branching portion D in the middle in the horizontal direction.

[0125] The upstream straight pipe portion 85u and the downstream straight pipe portion 85d of the main flow pipe portion 85 are continuously provided in a straight pipe shape vertically downward, so the refrigerant flowing into the upstream straight pipe portion 85u easily flows straight downward in the downstream straight pipe portion 85d. At this time, a small amount of refrigerant attempts to flow toward the elbow pipe portion 86 from the branching portion D, but is blocked by the flow of the refrigerant flowing in the main flow pipe portion 85 in the vertical direction downward, and the front end of the elbow pipe portion 86 is a dead end DE, so it is possible to reduce the possibility that the refrigerant and the refrigerant oil are left in the dead end DE.

[0126] Figure 9 is a schematic view of a third example of an eighth branch pipe of an outdoor unit of an embodiment of the present application.

[0127] As shown, the eighth branch pipe 68C of the third example of the outdoor unit 5 of the present embodiment has an upside-down T-shaped branching portion D. Figure 9

[0128] The upstream straight pipe portion 85u and the downstream straight pipe portion 85d of the main flow pipe portion 85 are continuously provided in a straight pipe shape in the horizontal direction. The main flow pipe portion 85 crosses the straight pipe portion 86a of the elbow pipe portion 86. That is, the shape of the branching portion D is an upside-down T shape described by the main flow pipe portion 85 extending in the horizontal direction and the straight pipe portion 86a of the elbow pipe portion 86 extending in the vertical direction crossing the main flow pipe portion 85 and branching.

[0129] In the eighth branch pipe 68C shown, the refrigerant flowing from the upstream straight pipe portion 85u to the branching portion D is introduced into the downstream straight pipe portion 85d by the inertial force and the suction pressure of the compressor 2 and proceeds straight. At this time, a small amount of refrigerant attempts to flow upward in the branching portion D, but is blocked by the elbow pipe portion 86 having the straight pipe portion 86a extending upward, and the front end of the elbow pipe portion 86 is a dead end DE, so the possibility that the refrigerant and the refrigerant oil are left in the dead end DE is reduced. Figure 9

[0130] is a schematic view of a fourth example of an eighth branch pipe of an outdoor unit of an embodiment of the present application. Figure 10 As shown, the eighth branch pipe 68D of the fourth example of the outdoor unit 5 of the present embodiment has a first branching portion D and a second branching portion D'.

[0131] Figure 10

[0132] ​​​The eighth branch pipe 68D of the fourth example has the second branch portion D' midway through the straight pipe portion 86a of the elbow portion 86 extending in the vertical direction downward from the pipe connection portion 43 in the eighth branch pipe 68A of the first example. The second main flow pipe portion 85' through which refrigerant flowing into the compressor 2 via the first switching valve 12A is connected to the second branch portion D'.

[0133] In addition, in a case where the air conditioning device is caused to perform the cooling operation, refrigerant is sucked into the compressor 2 via the first switching valve 12A. That is, one of the switching states of the first switching valve 12A in which refrigerant sucked into the compressor 2 via the first switching valve 12A flows in the second main flow pipe portion 85' corresponds to the switching state of the first switching valve 12A in the full cooling operation of the air conditioning device 1.

[0134] The second main flow pipe portion 85' has a second upstream straight pipe portion 85u' that sends refrigerant from the first switching valve 12A to the second branch portion D'.

[0135] The second upstream straight pipe portion 85u' is connected to the downstream straight pipe portion 85d via the second branch portion D' and the elbow portion 86 at which the first branch portion D and the first branch portion D converge.

[0136] The second upstream straight pipe portion 85u' branches and crosses the straight pipe portion 86a of the elbow portion 86 at an angle θ2' of 90 degrees or more. Preferably, the second upstream straight pipe portion 85u' branches and crosses the straight pipe portion 86a extending to the pipe connection portion 43 at an angle θ1' of 90 degrees or less. As an example, the shape of the second branch portion D' is a lying T shape drawn by the straight pipe portion 86a extending to the pipe connection portion 43 of the elbow portion 86 as a continuous straight pipe extending in the vertical direction and the second upstream straight pipe portion 85u' abutting against the straight pipe in the horizontal direction.

[0137] The eighth branch pipe 68D of the fourth example has the second branch portion D', the second main flow pipe portion 85', and the second upstream straight pipe portion 85u', and is the same as the structure of the eighth branch pipe 68A of the first example except that the first switching valve 12A is connected to the second main flow pipe portion 85', and the detailed description thereof is omitted for the same portions.

[0138] During cooling operation, the refrigerant flowing in the eighth branch pipe 68D reaches the second branch portion D' from the second upstream straight pipe portion 85u', is introduced into the bend portion 86 under the action of the suction pressure of the compressor 2, and after passing through the bend portion 86, is introduced into the downstream straight pipe portion 85d and flows downward under the action of gravity and the suction pressure of the compressor 2. At this time, a small amount of refrigerant flows downward in the second branch portion D', and the refrigerant and refrigeration oil may be retained. However, during heating operation, the refrigerant flowing into the eighth branch pipe 68D from the second switching valve 12B and the third switching valve 12C is blocked by the bend portion 86 having the straight pipe portion 86a extending upward, and the front end of the bend portion 86 is a dead end DE, so it is connected to the dead end DE. Figure 6 Compared with the comparative example shown, the possibility of stagnation of refrigerant and refrigeration oil is reduced.

[0139] Figure 11 This is a block diagram of a third embodiment of the air-conditioning apparatus according to the embodiment of the present invention.

[0140] like Figure 11 As shown, the outdoor unit 5 of the air conditioning apparatus 1 of this embodiment may also include a recovery pipe 101 connected to the pipe connection portion 43 and the suction side of the accumulator 16. The recovery pipe 101 directly connects the dead ends DE of the eighth branch pipes 68, 68A, 68B, 68C, and 68D to the vicinity of the accumulator 16 connected to the eighth branch pipes 68, 68A, 68B, 68C, and 68D, respectively, and recovers the refrigerant and refrigeration oil accumulated in the dead ends DE to the compressor 2. Specifically, the recovery pipe 101 directly connects the dead ends DE to the vicinity of the accumulator 16, bypassing the branching portions of the eighth branch pipes 68, 68A, 68B, 68C, and 68D, i.e., the branching portions toward the three switching valves 12A, 12B, and 12C.

[0141] The eighth branch pipes 68A, 68B, 68C, and 68D in the first through fourth examples originally have piping structures designed to prevent refrigerant and refrigeration oil from accumulating in the dead-end DE. Therefore, the amount of refrigerant and refrigeration oil that could potentially accumulate in the dead-end DE is minimal. However, as long as flow occurs in the main pipe section 85, it is difficult to completely prevent refrigerant and refrigeration oil from entering the dead-end DE. The recovery pipe 101 completely eliminates any trace of refrigerant and refrigeration oil accumulating in the dead-end DE.

[0142] As described above, the outdoor unit 5 of the present embodiment is provided with the first switching valve 12A capable of cutting off the connection of the discharge side of the compressor 2 with the indoor heat exchangers 21A, 21B,... of all the indoor units 6A, 6B,... and causing the outdoor heat exchanger 13 to function as a condenser, or connecting the discharge side of the compressor 2 with the indoor heat exchanger 21A, 21B,... of at least one of the indoor units 6A, 6B,... and causing the indoor heat exchanger 21A, 21B,... of at least one of the indoor units 6A, 6B,... to function as a condenser, and the second switching valve 12B capable of connecting the discharge side of the compressor 2 with the outdoor heat exchanger 13 and causing the outdoor heat exchanger 13 to function as a condenser, or connecting the suction side of the compressor 2 with the outdoor heat exchanger 13 and causing the outdoor heat exchanger 13 to function as an evaporator. In addition, the outdoor unit 5 is provided with the seventh branch pipe 67 as an outdoor first pipe connecting the outdoor heat exchanger 13 with the indoor units 6A, 6B,..., the tenth pipe 70 as an outdoor second pipe, which is one of the branches of the first switching valve 12A, connecting the compressor 2 with the indoor units 6A, 6B,..., and the eighth branch pipes 68A, 68B, 68C, 68D as outdoor third pipes connected with one of the branches of the first switching valve 12A and connecting the compressor 2 with the indoor units 6A, 6B,... bypassing the first switching valve 12A.

[0143] Also, the eighth branch pipes 68A, 68B, 68C, 68D are provided with the main flow pipe portion 85 for the flow of the refrigerant sucked into the compressor 2 via the first switching valve 12A in one switching state of the first switching valve 12A, and the elbow pipe portion 86 descending downward to the rear lower side crossing the main flow pipe portion 85. Thus, the air conditioning apparatus 1 and the outdoor unit 5 can reduce the possibility of the refrigerant and the refrigeration oil remaining in the part of the refrigerant pipe 8 which becomes a dead end DE in the second mode.

[0144] Further, the outdoor unit 5 of the present embodiment is provided with a first switching valve 12A capable of cutting off the connection of the discharge side of the compressor 2 to the indoor heat exchangers 21A, 21B,... of all the indoor units 6A, 6B,... and causing the outdoor heat exchanger 13 to function as a condenser, or connecting the discharge side of the compressor 2 to the indoor heat exchanger 21A, 21B,... of at least one of the indoor units 6A, 6B,... and causing the indoor heat exchanger 21A, 21B,... of at least one of the indoor units 6A, 6B,... to function as a condenser, and a second switching valve 12B capable of connecting the discharge side of the compressor 2 to the outdoor heat exchanger 13 and causing the outdoor heat exchanger 13 to function as a condenser, or connecting the suction side of the compressor 2 to the outdoor heat exchanger 13 and causing the outdoor heat exchanger 13 to function as an evaporator. Further, the outdoor unit 5 is provided with a seventh branch pipe 67 as an outdoor first pipe connecting the outdoor heat exchanger 13 to the indoor units 6A, 6B,..., a tenth pipe 70 as an outdoor second pipe which is one of the branches of the first switching valve 12A and connects the compressor 2 to the indoor units 6A, 6B,..., and eighth branch pipes 68A, 68B, 68C, 68D as outdoor third pipes which are connected to one of the branches of the first switching valve 12A and to the compressor 2. In the case where the seventh branch pipe 67, the tenth pipe 70, and the eighth branch pipes 68A, 68B, 68C, 68D are connected to the indoor units 6A, 6B,... via a plurality of switching units 7A, 7B,... capable of switching the flow direction of the refrigerant flowing in the indoor units 6A, 6B,..., the eighth branch pipes 68A, 68B, 68C, 68D connect the compressor 2 to the indoor units 6A, 6B,... bypassing the first switching valve 12A.

[0145] Further, in the case where the seventh branch pipe 67 and the tenth pipe 70 are connected to the indoor units 6A, 6B,... without passing through the plurality of switching units, the eighth branch pipes 68A, 68B, 68C, 68D are provided with a main flow pipe portion 85 for the refrigerant sucked into the compressor 2 via the first switching valve 12A in one switching state of the first switching valve 12A, and an elbow portion 86 descending downward rearward crossing the main flow pipe portion 85. Thus, the air conditioning apparatus 1 and the outdoor unit 5 can reduce the possibility of the refrigerant and the refrigerant oil remaining in the portion of the refrigerant pipe 8 which becomes a dead end DE in the second mode.

[0146] Further, the outdoor unit 5 of the present embodiment is provided with a downstream straight pipe portion 85d extending downward vertically from the branch portion D of the main flow pipe portion 85 and the elbow portion 86 to cause the liquid component contained in the refrigerant to flow downward vertically. Thus, the air conditioning apparatus 1 and the outdoor unit 5 can reduce the possibility of the refrigerant and the refrigerant oil remaining in the portion which becomes a dead end DE in the second mode, and can cause the liquid component contained in the refrigerant to return to the compressor 2 smoothly.

[0147] Further, the outdoor unit 5 of the present embodiment is provided with a recovery pipe 101 that connects the eighth branch pipes 68, 68A, 68B, 68C, 68D to the suction side of the compressor 2. Therefore, the air conditioning device 1 and the outdoor unit 5 can completely eliminate the slight stagnation of refrigerant and refrigerant oil in the dead end DE.

[0148] Further, the air conditioning device 1 of the present embodiment is provided with the outdoor unit 5, the plurality of indoor units 6A, 6B, and the plurality of switching units 7A, 7B,. The air conditioning device 1 provided with the plurality of switching units 7A, 7B, can cause the flow directions of the refrigerant flowing in the plurality of indoor units 6A, 6B, to be different between the indoor units 6A, 6B, performing the cooling operation and the indoor units 6A, 6B, performing the heating operation. The air conditioning device 1 of the present embodiment can also be provided with the outdoor unit 5 and the plurality of indoor units 6A, 6B, and block one branch of the first switching valve 12A. The air conditioning device 1 provided with the plurality of switching units 7A, 7B, and blocking one branch of the first switching valve 12A can cause the flow directions of the refrigerant flowing in the plurality of indoor units 6A, 6B, to be uniform and cause all of the indoor units 6A, 6B, to perform the cooling operation or the heating operation. That is, the air conditioning device 1 can function as a heat recovery multi-connected air conditioning device by selecting the plurality of switching units 7A, 7B, and function as a multi-connected air conditioning device by selecting the non-use of the plurality of switching units 7A, 7B,.

[0149] Therefore, the air conditioning device 1 and the outdoor unit 5 of the air conditioning device 1 of the present embodiment can be applied to either of the heat recovery type and the general multi-connected type, and can suppress the stagnation of refrigerant oil in the eighth branch pipes 68, 68A, 68B, 68C, 68D that are closed when applied to the multi-connected type.

[0150] Several embodiments of the present application have been described, but these embodiments are presented as examples and are not intended to limit the scope of the application. These new embodiments can be implemented in other various ways, and various omissions, substitutions, and changes can be made within the scope of the gist of the application. These embodiments, variations thereof, are included in the scope and gist of the application, and are included in the scope of the application recited in the claims and the scope of equivalents thereof.

[0151] Explanation of Reference Signs

[0152] 1…air conditioning apparatus, 2…compressor, 2a…accumulator, 5…outdoor unit, 6A, 6B, 6C…indoor unit, 7A, 7B, 7C…switching unit, 8…refrigerant pipe, 11…oil separator, 12A…first switching valve, 12B…second switching valve, 12C…third switching valve, 13…outdoor heat exchanger, 15, 15a, 15b…outdoor expansion valve, 16…accumulator, 17…outdoor fan, 18…inverter circuit, 19…control portion, 21A, 21B, 21C…indoor heat exchanger, 22A, 22B, 22C…indoor expansion valve, 23A, 23B, 23C…indoor fan, 25A, 25B, 25C…discharge gas pipe shutoff valve, 26A, 26B, 26C…suction gas pipe shutoff valve, 28…passage, 29…header, 31a…main heat exchanger, 31b…sub heat exchanger, 35, 36, 37, 38A, 38B, 38C, 39A, 39B, 39C…connection pipe, 41, 42, 43…pipe connection portion of outdoor unit, 45A, 45B, 45C, 46A, 46B, 46C, 47A, 47B, 47C…pipe connection portion of outdoor unit side of switching unit, 48A, 48B, 48C, 49A, 49B, 49C…pipe connection portion of indoor unit side of switching unit, 51A, 51B, 51C, 52A, 52B, 52C…pipe connection portion of indoor unit, 61…first pipe, 62…second branch pipe, 63…third pipe, 64…fourth pipe, 65…fifth pipe, 66…sixth pipe, 67…seventh branch pipe, 68, 68A, 68B, 68C, 68D…eighth branch pipe, 69…ninth pipe, 70…tenth pipe, 71A, 71B, 71C…eleventh pipe, 72A, 72B, 72C…twelfth branch pipe, 73A, 73B, 73C…thirteenth pipe, 74A, 74B, 74C…fourteenth pipe, 75A, 75B, 75C…fifteenth pipe, 76A, 76B, 76C…sixteenth pipe, 77A, 77B, 77C…seventeenth pipe, 81…sealing plug, 85…main flow pipe portion, 85…main flow pipe portion, 85u…upstream straight pipe portion, 85u…upstream straight pipe portion, 85d…downstream straight pipe portion, 85d…downstream straight pipe portion, 86…elbow pipe portion, 86a…straight pipe portion, 86b…bend portion, 88…gas-liquid separation portion, 101…recovery pipe.

Claims

1. An outdoor unit of an air conditioning apparatus, comprising: a compressor that compresses a refrigerant; an outdoor heat exchanger that exchanges heat between the refrigerant and outside air; a first switching valve that is capable of either cutting off a connection between a discharge side of the compressor and indoor heat exchangers of all indoor units to cause the outdoor heat exchanger to function as a condenser or connecting the discharge side of the compressor and the indoor heat exchanger of at least one of the indoor units to cause the indoor heat exchanger of the at least one of the indoor units to function as a condenser; a second switching valve that is capable of either connecting a discharge side of the compressor and the outdoor heat exchanger to cause the outdoor heat exchanger to function as a condenser or connecting a suction side of the compressor and the outdoor heat exchanger to cause the outdoor heat exchanger to function as an evaporator; an outdoor first pipe that connects the outdoor heat exchanger and the indoor units; an outdoor second pipe that is one of branches of the first switching valve, which connects the compressor and the indoor units; and an outdoor third pipe that is connected to one of the branches of the first switching valve and connects the compressor and the indoor units bypassing the first switching valve, the outdoor third pipe comprising: a main flow pipe portion through which the refrigerant sucked into the compressor via the first switching valve flows; and an elbow pipe portion that branches from the main flow pipe portion and descends rearward and downward.

2. An outdoor unit of an air conditioning apparatus, comprising: a compressor that compresses a refrigerant; an outdoor heat exchanger that exchanges heat between the refrigerant and outside air; a first switching valve that is capable of either cutting off a connection between a discharge side of the compressor and indoor heat exchangers of all indoor units to cause the outdoor heat exchanger to function as a condenser or connecting the discharge side of the compressor and the indoor heat exchanger of at least one of the indoor units to cause the indoor heat exchanger of the at least one of the indoor units to function as a condenser; a second switching valve that is capable of either connecting a discharge side of the compressor and the outdoor heat exchanger to cause the outdoor heat exchanger to function as a condenser or connecting a suction side of the compressor and the outdoor heat exchanger to cause the outdoor heat exchanger to function as an evaporator; an outdoor first pipe that connects the outdoor heat exchanger and the indoor units; an outdoor second pipe that is one of branches of the first switching valve, which connects the compressor and the indoor units; and an outdoor third pipe that is connected to one of the branches of the first switching valve and connected to the compressor, in a case where the outdoor first pipe, the outdoor second pipe, and the outdoor third pipe are connected to the indoor units via a plurality of switching units capable of switching a flow direction of the refrigerant flowing in the indoor units, the outdoor third pipe connects the compressor and the indoor units bypassing the first switching valve. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ In a case where the outdoor first pipe and the outdoor second pipe are not connected with the indoor unit via the plurality of switching units, the outdoor third pipe includes a main flow pipe portion through which the refrigerant sucked into the compressor via the first switching valve flows, and a bent pipe portion which branches from the main flow pipe portion and descends downward rearward.

3. The outdoor unit of the air conditioning apparatus according to claim 1 or 2, wherein The main flow pipe portion has a straight pipe portion which extends downward vertically from a branching portion of the main flow pipe portion and the bent pipe portion to cause the liquid component contained in the refrigerant to flow downward vertically.

4. The outdoor unit of the air conditioning apparatus according to any one of claims 1 to 3, wherein A recovery pipe which connects the outdoor third pipe and the suction side of the compressor is provided.

5. An air conditioning apparatus comprising: The outdoor unit according to any one of claims 1 to 4; and A plurality of indoor units which cause the refrigerant to exchange heat with air in an indoor space, The outdoor unit has an outdoor expansion valve which is connected to the discharge side of the outdoor heat exchanger, Each of the indoor units has an indoor heat exchanger and an indoor expansion valve which is connected to the outdoor heat exchanger, In a case where a plurality of switching units which can switch the flow direction of the refrigerant flowing in the corresponding indoor unit are provided, the flow direction of the refrigerant flowing in the plurality of indoor units can be made different from each other to exist mixedly the indoor unit which performs the cooling operation and the indoor unit which performs the heating operation, In a case where the plurality of switching units are not provided, the flow direction of the refrigerant flowing in the plurality of indoor units is made uniform to cause all of the indoor units to perform the cooling operation or the heating operation in such a manner that the refrigerant is sucked into the compressor through the first switching valve at the time of the cooling operation and is delivered to the plurality of indoor units through the first switching valve at the time of the heating operation.

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