Patent Application
20220243962
The present disclosure relates to a refrigerant cycle system.
Conventionally, a refrigerant cycle system including one refrigerant circuit configured by connecting a plurality of indoor units to one outdoor unit has been used.
For example, in a multi-room air conditioning apparatus described in Patent Literature 1 (JP 2011-257097 A), it is proposed to execute air conditioning in each room by using a refrigerant circuit in which a plurality of indoor units provided in rooms different from each other is connected to an outdoor unit.
A refrigerant cycle system according to one or more embodiments includes a first refrigerant circuit and a second refrigerant circuit independent of the first refrigerant circuit, and includes a heat source-side unit, a first use-side unit, a first liquid refrigerant connection pipe, a first gas refrigerant connection pipe, a second use-side unit, a second liquid refrigerant connection pipe, and a second gas refrigerant connection pipe. The heat source-side unit includes a heat source-side heat exchanger. The heat source-side heat exchanger includes a first heat source-side heat exchange unit constituting part of the first refrigerant circuit and a second heat source-side heat exchange unit constituting part of the second refrigerant circuit. The first use-side unit includes a first use-side heat exchanger constituting part of the first refrigerant circuit. The first liquid refrigerant connection pipe connects the first use-side unit to the heat source-side unit and constitutes part of the first refrigerant circuit. The first gas refrigerant connection pipe connects the first use-side unit to the heat source-side unit and constitutes part of the first refrigerant circuit. The second use-side unit includes a second use-side heat exchanger constituting part of the second refrigerant circuit. The second liquid refrigerant connection pipe connects the second use-side unit to the heat source-side unit and constitutes part of the second refrigerant circuit. The second gas refrigerant connection pipe connects the second use-side unit to the heat source-side unit and constitutes part of the second refrigerant circuit. A refrigerant classified by ISO817 as lower flammability (A2L) is charged into each of the first refrigerant circuit and the second refrigerant circuit.
(1) Configuration of Air Conditioning Apparatus of First Embodiment
An air conditioning apparatus 1 will be described with reference to the drawings.
The air conditioning apparatus 1 mainly includes, as shown in
The first indoor unit 6 and the outdoor unit 2 constitute part of the first refrigerant circuit 10 by connection via the first liquid-side refrigerant connection pipe 65 and the first gas-side refrigerant connection pipe 66. The second indoor unit 7 and the outdoor unit 2 constitute part of the first refrigerant circuit 10 by connection via the second liquid-side refrigerant connection pipe 75 and the second gas-side refrigerant connection pipe 76. In this way, the first refrigerant circuit 10 is configured by connecting the first indoor unit 6 and the second indoor unit 7 in parallel to the outdoor unit 2. R32, which is a refrigerant classified by ISO817 as lower flammability (A2L), is charged into the first refrigerant circuit 10 such that the amount is less than 1.84 kg.
The third indoor unit 8 and the outdoor unit 2 constitute part of the second refrigerant circuit 20 by connection via the third liquid-side refrigerant connection pipe 85 and the third gas-side refrigerant connection pipe 86. The fourth indoor unit 9 and the outdoor unit 2 constitute part of the second refrigerant circuit 20 by connection via the fourth liquid-side refrigerant connection pipe 95 and the fourth gas-side refrigerant connection pipe 96. In this way, the second refrigerant circuit 20 is configured by connecting the third indoor unit 8 and the fourth indoor unit 9 in parallel to the outdoor unit 2. R32, which is a refrigerant classified by ISO817 as lower flammability (A2L), is charged into the second refrigerant circuit 20 as well such that the amount is less than 1.84 kg.
A pipe with an outer diameter of 6.35 mm and an inner diameter of less than 4.75 mm is used in all the first liquid-side refrigerant connection pipe 65, the second liquid-side refrigerant connection pipe 75, the third liquid-side refrigerant connection pipe 85, and the fourth liquid-side refrigerant connection pipe 95. Specifically, the pipe has the same outer diameter as nibukan, which is widely distributed as a refrigerant pipe used for a refrigerant circuit of an air conditioning apparatus, and has a smaller inner diameter than nibukan. With this configuration, when the use of nibukan, which has been widely used in the past, causes the inner diameter to be too large, the inner diameter can be reduced to an appropriate size, and it is easy to reduce the amount of refrigerant charged into the first refrigerant circuit 10 and the second refrigerant circuit 20. Therefore, even if a refrigerant leak occurs, it is possible to reduce the amount of leak. By setting the outer diameter to the same diameter as nibukan, which has been widely used in the past, it is possible to improve the diversion of tools used based on the outer diameter. For the first gas-side refrigerant connection pipe 66, the second gas-side refrigerant connection pipe 76, the third gas-side refrigerant connection pipe 86, and the fourth gas-side refrigerant connection pipe 96, an appropriate refrigerant pipe is used that is larger than nibukan, which is widely distributed as a refrigerant pipe used for a refrigerant circuit of an air conditioning apparatus, thereby reducing the pressure loss when the gas refrigerant passes.
(1-1) Outdoor Unit
The outdoor unit 2 is installed outside the air conditioning target space, for example, on the roof of a building, near a wall surface of a building, or the like.
The outdoor unit 2 includes part of the first refrigerant circuit 10, part of the second refrigerant circuit 20, an outdoor heat exchanger 30 commonly used for the first refrigerant circuit 10 and the second refrigerant circuit 20, and an outdoor fan 30a.
The outdoor fan 30a is one fan for supplying outdoor air to the outdoor heat exchanger 30, which is commonly used for the first refrigerant circuit 10 and the second refrigerant circuit 20. The outdoor fan 30a is controlled to be driven by the control unit 50 in an operating state in which a refrigerant is flowing through either the first refrigerant circuit 10 or the second refrigerant circuit 20.
The first refrigerant circuit 10 mainly includes a first compressor 11, a first four-way switching valve 12, a first accumulator 13, the outdoor heat exchanger 30, a first liquid pipe 14a, a second liquid pipe 14b, a first expansion valve 15a, a second expansion valve 15b, a first liquid-side shutoff valve 16a, a second liquid-side shutoff valve 16b, a first gas pipe 17a, a second gas pipe 17b, a first gas-side shutoff valve 18a, and a second gas-side shutoff valve 18b.
A first port, which is one of connection ports of the first four-way switching valve 12, is connected to a suction side of the first compressor 11 via the first accumulator 13. A second port, which is one of connection ports of the first four-way switching valve 12, is connected to a discharge side of the first compressor 11. A refrigerant pipe extending toward the outdoor heat exchanger 30 is connected to a third port, which is one of connection ports of the first four-way switching valve 12. A refrigerant pipe extending toward the first gas-side shutoff valve 18a and the second gas-side shutoff valve 18b is connected to a fourth port, which is one of connection ports of the first four-way switching valve 12. The refrigerant pipe is branched into the first gas pipe 17a and the second gas pipe 17b. The first gas-side shutoff valve 18a is provided at an end of the first gas pipe 17a. The second gas-side shutoff valve 18b is provided at an end of the second gas pipe 17b. In the first refrigerant circuit 10, a refrigerant pipe connected to the opposite side of the first four-way switching valve 12 side across the outdoor heat exchanger 30 is branched into the first liquid pipe 14a and the second liquid pipe 14b. The first expansion valve 15a is provided in the middle of the first liquid pipe 14a, and the first liquid-side shutoff valve 16a is provided at an end of the first liquid pipe 14a. The second expansion valve 15b is provided in the middle of the second liquid pipe 14b, and the second liquid-side shutoff valve 16b is provided at an end of the second liquid pipe 14b.
By the control unit 50 switching the connection state of the first to fourth ports, the first four-way switching valve 12 can be switched between a cooling operation state in which the refrigerant discharged from the first compressor 11 is sent to the outdoor heat exchanger 30 (see the broken line in the first four-way switching valve 12 in
The second refrigerant circuit 20 mainly includes a second compressor 21, a second four-way switching valve 22, a second accumulator 23, the outdoor heat exchanger 30, a third liquid pipe 24a, a fourth liquid pipe 24b, a third expansion valve 25a, a fourth expansion valve 25b, a third liquid-side shutoff valve 26a, a fourth liquid-side shutoff valve 26b, a third gas pipe 27a, a fourth gas pipe 27b, a third gas-side shutoff valve 28a, and a fourth gas-side shutoff valve 28b.
A fifth port, which is one of connection ports of the second four-way switching valve 22, is connected to a suction side of the second compressor 21 via the second accumulator 23. A sixth port, which is one of connection ports of the second four-way switching valve 22, is connected to a discharge side of the second compressor 21. A refrigerant pipe extending toward the outdoor heat exchanger 30 is connected to a seventh port, which is one of connection ports of the second four-way switching valve 22. A refrigerant pipe extending toward the third gas-side shutoff valve 28a and the fourth gas-side shutoff valve 28b is connected to an eighth port, which is one of connection ports of the second four-way switching valve 22. The refrigerant pipe is branched into the third gas pipe 27a and the fourth gas pipe 27b. The third gas-side shutoff valve 28a is provided at an end of the third gas pipe 27a. The fourth gas-side shutoff valve 28b is provided at an end of the fourth gas pipe 27b. In the second refrigerant circuit 20, a refrigerant pipe connected to the opposite side of the second four-way switching valve 22 side across the outdoor heat exchanger 30 is branched into the third liquid pipe 24a and the fourth liquid pipe 24b. The third expansion valve 25a is provided in the middle of the third liquid pipe 24a, and the third liquid-side shutoff valve 26a is provided at an end of the third liquid pipe 24a. The fourth expansion valve 25b is provided in the middle of the fourth liquid pipe 24b, and the fourth liquid-side shutoff valve 26b is provided at an end of the fourth liquid pipe 24b.
By the control unit 50 switching the connection state of the fifth to eighth ports, the second four-way switching valve 22 can be switched between the cooling operation state in which the refrigerant discharged from the second compressor 21 is sent to the outdoor heat exchanger 30 (see the broken line in the second four-way switching valve 22 in
(1-2) Indoor Unit
In the first embodiment, as the plurality of indoor units, the first indoor unit 6, the second indoor unit 7, the third indoor unit 8, and the fourth indoor unit 9 are provided. Each indoor unit is installed in an independent or continuous space, and can be a ceiling-embedded, ceiling-suspended, wall-mounted, or floor-mounted unit.
The first indoor unit 6 mainly includes a first indoor heat exchanger 61, a first indoor fan 62, and a first remote control device 63. The first indoor fan 62 forms an air flow obtained by taking in air of a target space for the first indoor unit 6 and returning the air to the target space again via the first indoor heat exchanger 61. The liquid refrigerant side of the first indoor heat exchanger 61 is connected to the first liquid-side shutoff valve 16a of the outdoor unit 2 via the first liquid-side refrigerant connection pipe 65. The gas refrigerant side of the first indoor heat exchanger 61 is connected to the first gas-side shutoff valve 18a of the outdoor unit 2 via the first gas-side refrigerant connection pipe 66. The first remote control device 63 is communicably connected to the control unit 50 and receives various operation commands from a user.
The second indoor unit 7 mainly includes a second indoor heat exchanger 71, a second indoor fan 72, and a second remote control device 73. The second indoor fan 72 forms an air flow obtained by taking in air of a target space for the second indoor unit 7 and returning the air to the target space again via the second indoor heat exchanger 71. The liquid refrigerant side of the second indoor heat exchanger 71 is connected to the second liquid-side shutoff valve 16b of the outdoor unit 2 via the second liquid-side refrigerant connection pipe 75. The gas refrigerant side of the second indoor heat exchanger 71 is connected to the second gas-side shutoff valve 18b of the outdoor unit 2 via the second gas-side refrigerant connection pipe 76. The second remote control device 73 is communicably connected to the control unit 50 and receives various operation commands from a user.
The third indoor unit 8 mainly includes a third indoor heat exchanger 81, a third indoor fan 82, and a third remote control device 83. The third indoor fan 82 forms an air flow obtained by taking in air of a target space for the third indoor unit 8 and returning the air to the target space again via the third indoor heat exchanger 81. The liquid refrigerant side of the third indoor heat exchanger 81 is connected to the third liquid-side shutoff valve 26a of the outdoor unit 2 via the third liquid-side refrigerant connection pipe 85. The gas refrigerant side of the third indoor heat exchanger 81 is connected to the third gas-side shutoff valve 28a of the outdoor unit 2 via the third gas-side refrigerant connection pipe 86. The third remote control device 83 is communicably connected to the control unit 50 and receives various operation commands from a user.
The fourth indoor unit 9 mainly includes a fourth indoor heat exchanger 91, a fourth indoor fan 92, and a fourth remote control device 93. The fourth indoor fan 92 forms an air flow obtained by taking in air of a target space for the fourth indoor unit 9 and returning the air to the target space again via the fourth indoor heat exchanger 91. The liquid refrigerant side of the fourth indoor heat exchanger 91 is connected to the fourth liquid-side shutoff valve 26b of the outdoor unit 2 via the fourth liquid-side refrigerant connection pipe 95. The gas refrigerant side of the fourth indoor heat exchanger 91 is connected to the fourth gas-side shutoff valve 28b of the outdoor unit 2 via the fourth gas-side refrigerant connection pipe 96. The fourth remote control device 93 is communicably connected to the control unit 50 and receives various operation commands from a user.
(1-3) Control Unit
The control unit 50 is a functional unit that controls operations of various devices constituting the air conditioning apparatus 1.
The control unit 50 is configured, for example, by communicably connecting an outdoor control unit (not shown) of the outdoor unit 2 via a transmission line (not shown) to an indoor control unit (not shown) provided in each of the first indoor unit 6, the second indoor unit 7, the third indoor unit 8, and the fourth indoor unit 9. Each of the outdoor control unit and the indoor control unit is a unit including, for example, a microcomputer and a memory storing various programs for controlling the air conditioning apparatus 1, and the like, the programs being executable by the microcomputer. Note that for convenience,
The control unit 50 is electrically connected to various devices such as the outdoor fan 30a, the first compressor 11, the first four-way switching valve 12, the first expansion valve 15a, the second expansion valve 15b, the second compressor 21, the second four-way switching valve 22, the third expansion valve 25a, and the fourth expansion valve 25b. The control unit 50 is electrically connected to various sensors (not shown). As described above, the control unit 50 is communicably connected to the first remote control device 63, the second remote control device 73, the third remote control device 83, and the fourth remote control device 93 operated by a user of the air conditioning apparatus 1.
The control unit 50 controls the operation and stop of the air conditioning apparatus 1 and the operation of various devices constituting the air conditioning apparatus 1, based on measurement signals of various sensors, commands received from the first remote control device 63, the second remote control device 73, the third remote control device 83, and the fourth remote control device 93, and the like.
(2) Configuration of Outdoor Heat Exchanger
The outdoor heat exchanger 30 includes a plurality of first heat transfer tubes 31, a plurality of second heat transfer tubes 32, a plurality of heat transfer fins 33, a first gas header 34, a second gas header 35, a first distributor 36, and a second distributor 37.
The plurality of heat transfer fins 33 is arranged in the plate thickness direction, which is the paper surface direction in
The first gas header 34 is a header belonging to the first refrigerant circuit 10, and is provided on the gas side of the plurality of first heat transfer tubes 31 in the refrigerant flow path of the first refrigerant circuit 10. When the first refrigerant circuit 10 is in the cooling operation state, the first gas header 34 divides and supplies a gas refrigerant to a plurality of flow paths including the plurality of first heat transfer tubes 31. When the first refrigerant circuit 10 is in the heating operation state (see the refrigerant flow arrow in
The second gas header 35 is a header belonging to the second refrigerant circuit 20, and is provided on the gas side of the plurality of second heat transfer tubes 32 in the refrigerant flow path of the second refrigerant circuit 20. When the second refrigerant circuit 20 is in the cooling operation state, the second gas header 35 divides and supplies the gas refrigerant to a plurality of flow paths including the plurality of second heat transfer tubes 32. When the second refrigerant circuit 20 is in the heating operation state (see the refrigerant flow arrow in
The first distributor 36 is a distributor belonging to the first refrigerant circuit 10, and is provided on the liquid side of the plurality of first heat transfer tubes 31 in the refrigerant flow path of the first refrigerant circuit 10. When the first refrigerant circuit 10 is in the cooling operation state, the first distributor 36 merges the liquid refrigerant that has flowed through the plurality of flow paths including the plurality of first heat transfer tubes 31. When the first refrigerant circuit 10 is in the heating operation state (see the refrigerant flow arrow in
The second distributor 37 is a distributor belonging to the second refrigerant circuit 20, and is provided on the liquid side of the plurality of second heat transfer tubes 32 in the refrigerant flow path of the second refrigerant circuit 20. When the second refrigerant circuit 20 is in the cooling operation state, the second distributor 37 merges the liquid refrigerant that has flowed through the plurality of flow paths including the plurality of second heat transfer tubes 32. When the second refrigerant circuit 20 is in the heating operation state (see the refrigerant flow arrow in
The plurality of first heat transfer tubes 31 is heat transfer tubes belonging to the first refrigerant circuit 10, and the refrigerant flowing through the first refrigerant circuit 10 passes through the heat transfer tubes. The plurality of first heat transfer tubes 31 and the nearby heat transfer fins 33 are part of the outdoor heat exchanger 30, and constitute a first outdoor heat exchange unit 30x belonging to the first refrigerant circuit 10. The refrigerant flowing through the first refrigerant circuit 10 is divided into and flows through a plurality of flow paths that is in parallel with each other and corresponds to the number of pipes connected to the first distributor 36 in the outdoor heat exchanger 30. Specifically, each flow path corresponding to the number of pipes connected to the first distributor 36 includes a branch part at a position closer to the gas side, while ends of the first heat transfer tubes 31 are connected to turn back via a U-shaped tube or the like. Note that in the first embodiment, each flow path corresponding to the number of pipes connected to the first distributor 36 is configured such that the number of first heat transfer tubes 31 on the liquid refrigerant side of the branch part, and the total number of first heat transfer tubes 31 divided on the gas refrigerant side of the branch part are equal to each other. In the first embodiment, the plurality of first heat transfer tubes 31 is arranged such that the first heat transfer tubes 31 do not overlap each other in the air flow direction.
The plurality of second heat transfer tubes 32 is heat transfer tubes belonging to the second refrigerant circuit 20, and the refrigerant flowing through the second refrigerant circuit 20 passes through the heat transfer tubes. The plurality of second heat transfer tubes 32 and the nearby heat transfer fins 33 are part of the outdoor heat exchanger 30, and constitute a second outdoor heat exchange unit 30y belonging to the second refrigerant circuit 20. The refrigerant flowing through the second refrigerant circuit 20 is divided into and flows through a plurality of flow paths that is in parallel with each other and corresponds to the number of pipes connected to the second distributor 37 in the outdoor heat exchanger 30. Specifically, each flow path corresponding to the number of pipes connected to the second distributor 37 includes a branch part at a position closer to the gas side, while ends of the second heat transfer tube 32 are connected to turn back via a U-shaped tube or the like. Note that in the first embodiment, each flow path corresponding to the number of pipes connected to the second distributor 37 is configured such that the number of second heat transfer tubes 32 on the liquid refrigerant side of the branch part, and the total number of second heat transfer tubes 32 divided on the gas refrigerant side of the branch part are equal to each other. In the first embodiment, the plurality of second heat transfer tubes 32 is arranged such that the second heat transfer tubes 32 do not overlap each other in the air flow direction.
Note that as shown in
In the first embodiment, the outdoor heat exchanger 30 and the outdoor fan 30a are provided such that the direction of the refrigerant flow in the outdoor heat exchanger 30 is parallel to the direction of the air flow supplied from the outdoor fan 30a to the outdoor heat exchanger 30, when the first refrigerant circuit 10 and the second refrigerant circuit 20 are both in the heating operation state as shown in the refrigerant flow of the heating operation state in
(3) Characteristics of First Embodiment
The air conditioning apparatus 1 of the first embodiment includes the plurality of indoor units: the first indoor unit 6, the second indoor unit 7, the third indoor unit 8, and the fourth indoor unit 9, and can process the heat load at the place where each indoor unit is disposed. Here, the air conditioning apparatus 1 processes the heat load at a plurality of places by using the plurality of refrigerant circuits independent of each other, the first refrigerant circuit 10 and the second refrigerant circuit 20. In this way, by processing the heat load at a plurality of places by using the plurality of refrigerant circuits, it is possible to keep the amount of refrigerant charged into one refrigerant circuit to a lower level than the case of using one refrigerant circuit, and specifically, to keep the amount of refrigerant charged into one refrigerant circuit to less than 1.84 kg.
Therefore, even if R32, which is a refrigerant classified by ISO817 as lower flammability (A2L), is charged into each of the first refrigerant circuit 10 and the second refrigerant circuit 20, it is possible to keep the amount of refrigerant leak to a low level when a refrigerant leak occurs in either the first refrigerant circuit 10 or the second refrigerant circuit 20. Therefore, even if a refrigerant leak occurs, it is possible to keep the combustion possibility to a low level.
In particular, in the air conditioning apparatus 1 of the first embodiment, a pipe with an outer diameter of 6.35 mm and an inner diameter of less than 4.75 mm is used in the first liquid-side refrigerant connection pipe 65, the second liquid-side refrigerant connection pipe 75, the third liquid-side refrigerant connection pipe 85, and the fourth liquid-side refrigerant connection pipe 95. Therefore, by keeping the inner diameter smaller than that of nibukan, which is widely distributed, the area of the flow path in a relatively high density place can be narrowed in the refrigerant circuit, and the amount of charged refrigerant can be kept to a low level.
Note that if the amount of refrigerant charged into the refrigerant circuit is kept to a low level in this way, the pressure loss is likely to occur in the refrigerant flowing through the refrigerant circuit during the refrigeration cycle. By using R32, which is a refrigerant that is less likely to cause the pressure loss than R410A or the like, such a decrease in efficiency caused by the pressure loss can be kept to a low level.
The heat transfer fins 33 of the outdoor heat exchanger 30 are attached such that the plurality of first heat transfer tubes 31 belonging to the first refrigerant circuit 10 and the plurality of second heat transfer tubes 32 belonging to the second refrigerant circuit 20 penetrate. This allows the outdoor heat exchanger 30 to give and receive heat between the refrigerant flowing through the first refrigerant circuit 10 and the refrigerant flowing through the second refrigerant circuit 20, via the heat transfer fins 33 to which both the first heat transfer tubes 31 and the second heat transfer tubes 32 are attached. In particular, in the outdoor heat exchanger 30 of the first embodiment, for example, unlike the case where the heat transfer tubes are provided in only one row in the air flow direction, many places are secured where the plurality of first heat transfer tubes 31 belonging to the first refrigerant circuit 10 and the plurality of second heat transfer tubes 32 belonging to the second refrigerant circuit 20 are disposed adjacent to each other. Specifically, in the outdoor heat exchanger 30 of the first embodiment, places where the first heat transfer tubes 31 and the second heat transfer tubes 32 are located within a distance range of equal to or less than twice the closest pitch of the plurality of first heat transfer tubes 31 arranged vertically are secured in half or more of the total number of plurality of first heat transfer tubes 31, enabling sufficient giving and receiving of heat between the refrigerant flowing through the first refrigerant circuit 10 and the refrigerant flowing through the second refrigerant circuit 20. This makes it possible to use the capacity of one refrigerant circuit by the other refrigerant circuit between the first refrigerant circuit 10 and the second refrigerant circuit 20. For example, when the cooling operation is executed in the first refrigerant circuit 10 and the heating operation is executed in the second refrigerant circuit 20 simultaneously by using the first indoor unit 6 and the second indoor unit 7 belonging to the first refrigerant circuit 10 for cooling a computer room or the like, it is possible to increase both the cooling capacity of the first refrigerant circuit 10 and the heating capacity of the second refrigerant circuit 20 by giving and receiving heat between the first refrigerant circuit 10 and the second refrigerant circuit 20 in the outdoor heat exchanger 30.
In the air conditioning apparatus 1 of the first embodiment, the outdoor heat exchanger 30 can be shared by the first refrigerant circuit 10 and the second refrigerant circuit 20. An air flow can be supplied to the outdoor heat exchanger 30 by using one outdoor fan 30a. This allows the outdoor fan 30a to be shared by the first refrigerant circuit 10 and the second refrigerant circuit 20.
Note that the outdoor heat exchanger 30 of the air conditioning apparatus 1 of the first embodiment is configured such that the number of first heat transfer tubes 31 belonging to the first refrigerant circuit 10 and the number of second heat transfer tubes 32 belonging to the second refrigerant circuit 20 arranged on the windward side are equal to each other. This makes it easier to balance the capacity of the first refrigerant circuit 10 and the second refrigerant circuit 20.
In the air conditioning apparatus 1 of the first embodiment, R32 is charged as a refrigerant into the first refrigerant circuit 10 and the second refrigerant circuit 20. The pressure loss when the R32 refrigerant passes through a heat exchanger used as an evaporator is kept to a lower level than conventionally used R410A. Therefore, by executing the heating operation in the first refrigerant circuit 10 or the second refrigerant circuit 20, even when the outdoor heat exchanger 30 functions as a refrigerant evaporator, it is possible to keep the temperature drop at a refrigerant outlet of the outdoor heat exchanger 30 to a low level. This makes it possible to suppress frost formation in the outdoor heat exchanger 30.
Therefore, for example, as shown in
(4) Modifications of First Embodiment
(4-1) Modification A of First Embodiment
The first embodiment has described, by way of example, a case where R32, which is not a non-azeotropic mixed refrigerant, is used in the first refrigerant circuit 10 and the second refrigerant circuit 20.
In contrast, a non-azeotropic mixed refrigerant, which is a refrigerant classified by ISO817 as lower flammability (A2L), may be used in each of the first refrigerant circuit 10 and the second refrigerant circuit 20.
When a refrigerant cycle is performed in a refrigerant circuit into which the non-azeotropic mixed refrigerant is charged and the outdoor heat exchanger 30 functions as a refrigerant evaporator, the composition differs between the gas phase and the liquid phase of the refrigerant, and the temperature of the refrigerant on the downstream side of the refrigerant flowing through the outdoor heat exchanger 30 tends to rise. Therefore, for example, when the flow paths in the outdoor heat exchanger 30 include a plurality of heat transfer tubes belonging to the same refrigerant circuit, when the heat transfer tubes arranged on the windward side and the heat transfer tubes arranged on the downwind side are arranged in line in the air flow direction in the same flow path, in particular, it becomes difficult to sufficiently secure the temperature difference between the refrigerant flowing through the heat transfer tubes arranged on the downwind side and the air
In contrast, the outdoor heat exchanger 30 of the air conditioning apparatus 1 includes the plurality of first heat transfer tubes 31 belonging to the first refrigerant circuit 10 and the plurality of second heat transfer tubes 32 belonging to the second refrigerant circuit 20. The plurality of first heat transfer tubes 31 does not line up with each other in the air flow direction, and the plurality of second heat transfer tubes 32 does not line up with each other in the air flow direction. Specifically, the outdoor heat exchanger 30 includes one first heat transfer tube 31 and one second heat transfer tube 32 arranged in this order in the air flow direction, and one second heat transfer tube 32 and one first heat transfer tube 31 arranged in this order. Therefore, when only the first refrigerant circuit 10 is in operation or only the second refrigerant circuit 20 is in operation, it is possible to supply outside air whose temperature has not changed (there is no temperature change due to heat exchange in the heat transfer tubes on the upstream side) to any of the heat transfer tubes. This makes it possible to sufficiently secure the temperature difference between the refrigerant and the air and exchange heat even in the heat transfer tubes arranged on the downstream side in the air flow direction.
Note that as a refrigerant to be charged in the refrigerant circuit, when using one or more selected from the group consisting of R454A, R454B, and R454C, which are non-azeotropic mixed refrigerants classified by ISO817 as lower flammability (A2L), in particular, the increase in the refrigerant temperature on the downstream side of the refrigerant flowing through the outdoor heat exchanger 30 becomes remarkable. Therefore, when these refrigerants are used as the non-azeotropic mixed refrigerant, the above-described effects can be sufficiently obtained.
(4-2) Modification B of First Embodiment
The outdoor heat exchanger 30 in the first embodiment described above has been described by taking as an example the case where the number of first heat transfer tubes 31 is equal to the number of second heat transfer tubes 32, and the area ratio occupied by the plurality of first heat transfer tubes 31 is equal to the area ratio occupied by the second heat transfer tubes 32 in the heat transfer fins 33.
In contrast, for example, when the total processing load in one or the plurality of indoor units belonging to the first refrigerant circuit 10 differs from the total processing load in one or the plurality of indoor units belonging to the second refrigerant circuit 20, the ratio of the number of first heat transfer tubes 31 and the number of second heat transfer tubes 32 may be changed according to the processing load to change the ratio of the area ratio occupied by the plurality of first heat transfer tubes 31 and the area ratio occupied by the second heat transfer tubes 32 in the heat transfer fins 33.
(4-3) Modification C of First Embodiment
The application of the first indoor unit 6, the second indoor unit 7, the third indoor unit 8, and the fourth indoor unit 9 in the first embodiment described above is not limited to air conditioning applications, nor is it limited to those commonly used in one type of application. These units may be used, for example, not only for air conditioning applications, but also for water heater applications and floor heating applications, and may be used in combination thereof.
(4-4) Modification D of First Embodiment
The air conditioning apparatus 1 in the first embodiment described above has been described by taking, as an example, the configuration in which in the outdoor heat exchanger 30, the refrigerant flow paths including the plurality of first heat transfer tubes 31 belonging to the first refrigerant circuit 10 and the refrigerant flow paths including the plurality of second heat transfer tubes 32 belonging to the second refrigerant circuit 20 intersect in the middle of the outdoor heat exchanger 30.
In contrast, like an outdoor heat exchanger 130 shown in
In this outdoor heat exchanger 130, the plurality of second heat transfer tubes 32 belonging to the second refrigerant circuit 20 is arranged to be gathered on the windward lower side. The plurality of first heat transfer tubes 31 belonging to the first refrigerant circuit 10 is provided at positions on the downwind side of the plurality of second heat transfer tubes 32 and positions above the plurality of second heat transfer tubes 32.
Note that in this outdoor heat exchanger 130, the number of first heat transfer tubes 31 is larger than the number of second heat transfer tubes 32. Therefore, for example, the outdoor heat exchanger can be used for an air conditioning apparatus in which the processing load of the first refrigerant circuit 10 is larger than the processing load of the second refrigerant circuit 20.
(4-5) Modification E of First Embodiment
The air conditioning apparatus 1 of the first embodiment described above has been described by taking, as an example, the case where one outdoor heat exchanger 30 is shared by the first refrigerant circuit 10 and the second refrigerant circuit 20.
In contrast, as shown in
(5) Configuration of Air Conditioning Apparatus of Second Embodiment
An air conditioning apparatus of the second embodiment is almost the same as the air conditioning apparatus of the first embodiment, and differences will be mainly described below.
In the air conditioning apparatus of the second embodiment, pipes having pipe diameters according to the capacity of indoor heat exchangers 61, 71, 81, and 91 included in indoor units 6 to 9 to be connected are used for a first liquid-side refrigerant connection pipe 65, a second liquid-side refrigerant connection pipe 75, a third liquid-side refrigerant connection pipe 85, and a fourth liquid-side refrigerant connection pipe 95, respectively. Note that the pipe diameter of each liquid-side refrigerant connection pipe is smaller than the pipe diameter of paired gas-side refrigerant connection pipe for each indoor unit.
Pipes having pipe diameters according to the capacity of the indoor heat exchangers 61, 71, 81, and 91 included in the indoor units 6 to 9 to be connected are used for a first gas-side refrigerant connection pipe 66, a second gas-side refrigerant connection pipe 76, a third gas-side refrigerant connection pipe 86, and a fourth gas-side refrigerant connection pipe 96, respectively. In particular, in the second embodiment, the pipe diameter of the first gas-side refrigerant connection pipe 66 differs from the pipe diameter of the second gas-side refrigerant connection pipe 76. The pipe diameter of the first gas-side refrigerant connection pipe 66 is larger than the pipe diameter of the second gas-side refrigerant connection pipe 76. The pipe diameter of the third gas-side refrigerant connection pipe 86 differs from the pipe diameter of the fourth gas-side refrigerant connection pipe 96. The pipe diameter of the third gas-side refrigerant connection pipe 86 is larger than the pipe diameter of the fourth gas-side refrigerant connection pipe 96. In the second embodiment, the pipe diameter of the first gas-side refrigerant connection pipe 66 is larger than the pipe diameter of the third gas-side refrigerant connection pipe 86, the pipe diameter of the third gas-side refrigerant connection pipe 86 is larger than the pipe diameter of the second gas-side refrigerant connection pipe 76, and the pipe diameter of the second gas-side refrigerant connection pipe 76 is larger than the pipe diameter of the fourth gas-side refrigerant connection pipe 96.
(5-1) Outdoor Unit
In an outdoor unit 2 of the air conditioning apparatus 1 of the second embodiment, the capacity of a first compressor 11 of a first refrigerant circuit 10 and the capacity of a second compressor 21 of a second refrigerant circuit 20 are equal to each other. Here, equal capacity means that, for example, compressors of variable capacity have equal cylinder volume.
(5-2) Indoor Unit
The first indoor unit 6, the second indoor unit 7, the third indoor unit 8, and the fourth indoor unit 9 of the air conditioning apparatus 1 of the second embodiment are similar to respective indoor units of the first embodiment described above.
(5-3) Control Unit
A control unit 50 of the air conditioning apparatus 1 of the second embodiment is similar to the control unit of the first embodiment described above.
(6) Configuration of Outdoor Heat Exchanger
An outdoor heat exchanger 30 of the air conditioning apparatus 1 of the second embodiment is similar to the outdoor heat exchanger of the first embodiment described above.
(7) Arrangement Configuration of Shutoff Valves in Outdoor Unit
The outdoor unit 2 include an outdoor casing 40, which is a substantially rectangular enclosure that houses above-described components inside (outdoor heat exchanger 30, outdoor fan 30a, first compressor 11, first four-way switching valve 12, first accumulator 13, first liquid pipe 14a, second liquid pipe 14b, first expansion valve 15a, second expansion valve 15b, first liquid-side shutoff valve 16a, second liquid-side shutoff valve 16b, first gas pipe 17a, second gas pipe 17b, first gas-side shutoff valve 18a, second gas-side shutoff valve 18b, second compressor 21, second four-way switching valve 22, second accumulator 23, third liquid pipe 24a, fourth liquid pipe 24b, third expansion valve 25a, fourth expansion valve 25b, third liquid-side shutoff valve 26a, fourth liquid-side shutoff valve 26b, third gas pipe 27a, fourth gas pipe 27b, third gas-side shutoff valve 28a, and fourth gas-side shutoff valve 28b).
The outdoor casing 40 is provided with a shutoff valve cover 41 that covers, from the side, the first liquid-side shutoff valve 16a, the second liquid-side shutoff valve 16b, the first gas-side shutoff valve 18a, the second gas-side shutoff valve 18b, the third liquid-side shutoff valve 26a, the fourth liquid-side shutoff valve 26b, the third gas-side shutoff valve 28a, and the fourth gas-side shutoff valve 28b. The rear of the shutoff valve cover 41 is open to pass each connection pipe to be connected to each shutoff valve. Here, the first liquid-side refrigerant connection pipe 65 is connected to the first liquid-side shutoff valve 16a. The second liquid-side refrigerant connection pipe 75 is connected to the second liquid-side shutoff valve 16b. The first gas-side refrigerant connection pipe 66 is connected to the first gas-side shutoff valve 18a. The second gas-side refrigerant connection pipe 76 is connected to the second gas-side shutoff valve 18b. The third liquid-side refrigerant connection pipe 85 is connected to the third liquid-side shutoff valve 26a. The fourth liquid-side refrigerant connection pipe 95 is connected to the fourth liquid-side shutoff valve 26b. The third gas-side refrigerant connection pipe 86 is connected to the third gas-side shutoff valve 28a. The fourth gas-side refrigerant connection pipe 96 is connected to the fourth gas-side shutoff valve 28b.
The first liquid-side shutoff valve 16a, the second liquid-side shutoff valve 16b, the first gas-side shutoff valve 18a, the second gas-side shutoff valve 18b, the third liquid-side shutoff valve 26a, the fourth liquid-side shutoff valve 26b, the third gas-side shutoff valve 28a, and the fourth gas-side shutoff valve 28b are fixed to a shutoff valve support plate 42, which includes sheet metal fixed to a bottom plate of the outdoor casing 40. Specifically, the valves are arranged in the order of, from the bottom, a pair of the first liquid-side shutoff valve 16a and the first gas-side shutoff valve 18a, a pair of the second liquid-side shutoff valve 16b and the second gas-side shutoff valve 18b, a pair of the third liquid-side shutoff valve 26a and the third gas-side shutoff valve 28a, and a pair of the fourth liquid-side shutoff valve 26b and the fourth gas-side shutoff valve 28b. In this way, the gas-side refrigerant connection pipes connected to respective gas-side shutoff valves are arranged such that the pipe diameter gradually decreases in order from the bottom.
Here, the first liquid-side refrigerant connection pipe 65, the second liquid-side refrigerant connection pipe 75, the third liquid-side refrigerant connection pipe 85, the fourth liquid-side refrigerant connection pipe 95, the first gas-side refrigerant connection pipe 66, the second gas-side refrigerant connection pipe 76, the third gas-side refrigerant connection pipe 86, and the fourth gas-side refrigerant connection pipe 96 all extend backward from respective shutoff valves and then are bent upward at curved portions 66R, 76R, 86R, and 96R of respective refrigerant connection pipes (only gas-side refrigerant connection pipe side is shown by the broken line in
(8) Characteristics of Second Embodiment
The air conditioning apparatus 1 of the second embodiment includes the plurality of indoor units: the first indoor unit 6, the second indoor unit 7, the third indoor unit 8, and the fourth indoor unit 9, and can process the heat load at the place where each indoor unit is disposed. Here, the air conditioning apparatus 1 processes the heat load at a plurality of places by using the plurality of refrigerant circuits independent of each other, the first refrigerant circuit 10 and the second refrigerant circuit 20. In this way, by processing the heat load at a plurality of places by using the plurality of refrigerant circuits, it is possible to keep the amount of refrigerant charged into one refrigerant circuit to a lower level than the case of using one refrigerant circuit, and specifically, to keep the amount of refrigerant charged into one refrigerant circuit to less than 1.84 kg.
Therefore, even if R32, which is a refrigerant classified by ISO817 as lower flammability (A2L), is charged into each of the first refrigerant circuit 10 and the second refrigerant circuit 20, it is possible to keep the amount of refrigerant leak to a low level when a refrigerant leak occurs in either the first refrigerant circuit 10 or the second refrigerant circuit 20. Therefore, even if a refrigerant leak occurs, it is possible to keep the combustion possibility to a low level.
The air conditioning apparatus 1 of the second embodiment includes four gas-side refrigerant connection pipes: the first gas-side refrigerant connection pipe 66, the second gas-side refrigerant connection pipe 76, the third gas-side refrigerant connection pipe 86, and the fourth gas-side refrigerant connection pipe 96. Out of these pipes, the two high-ranking pipes having a large pipe diameter, the first gas-side refrigerant connection pipe 66 and the third gas-side refrigerant connection pipe 86 belong to different refrigerant circuits. Specifically, the first gas-side refrigerant connection pipe 66 belongs to the first refrigerant circuit 10, and the third gas-side refrigerant connection pipe 86 belongs to the second refrigerant circuit 20. This makes it possible to suppress an imbalance of capacity between the refrigerant circuits and to make the shortage or excess of capacity difficult to occur in each indoor unit.
Out of the plurality of gas-side refrigerant connection pipes, the two low-ranking pipes having a small pipe diameter, the second gas-side refrigerant connection pipe 76 and the fourth gas-side refrigerant connection pipe 96 also belong to different refrigerant circuits. Specifically, the second gas-side refrigerant connection pipe 76 belongs to the first refrigerant circuit 10, and the fourth gas-side refrigerant connection pipe 96 belongs to the second refrigerant circuit 20. This makes it possible to further suppress the imbalance of capacity between the refrigerant circuits.
In particular, in the second embodiment, since the first compressor 11 of the first refrigerant circuit 10 and the second compressor 21 of the second refrigerant circuit 20 have the same capacity, it is possible to balance the capacity of respective refrigerant circuits, by providing different refrigerant circuits with the two high-ranking pipes having a large pipe diameter out of the plurality of gas-side refrigerant connection pipes, and by providing different refrigerant circuits with the two low-ranking pipes having a small pipe diameter out of the plurality of gas-side refrigerant connection pipes, as described above.
In the outdoor unit 2, the first gas-side shutoff valve 18a to which the first gas-side refrigerant connection pipe 66 belonging to the first refrigerant circuit 10 is connected, the third gas-side shutoff valve 28a to which the third gas-side refrigerant connection pipe 86 belonging to the second refrigerant circuit 20 is connected, the second gas-side shutoff valve 18b to which the second gas-side refrigerant connection pipe 76 belonging to the first refrigerant circuit 10 is connected, and the fourth gas-side shutoff valve 28b to which the fourth gas-side refrigerant connection pipe 96 belonging to the second refrigerant circuit 20 is connected are arranged in order from the bottom. Therefore, the gas-side shutoff valves belonging to the first refrigerant circuit 10 and the gas-side shutoff valves belonging to the second refrigerant circuit 20 can be arranged at staggered height positions. This makes it possible to avoid a structure in which only the gas-side shutoff valves belonging to either one of the refrigerant circuits are arranged together upward or downward, to equalize the head difference between the refrigerant circuits, and to equalize the capacity.
The refrigerant connection pipes extending from the outdoor unit 2 (first liquid-side refrigerant connection pipe 65, first gas-side refrigerant connection pipe 66, second liquid-side refrigerant connection pipe 75, second gas-side refrigerant connection pipe 76, third liquid-side refrigerant connection pipe 85, third gas-side refrigerant connection pipe 86, fourth liquid-side refrigerant connection pipe 95, and fourth gas-side refrigerant connection pipe 96) are all provided to extend upward from the outdoor casing 40. This makes it possible to lead each refrigerant connection pipe extending from the outdoor unit 2 to a higher position in the room or ceiling space, which is the air conditioning target space. This eliminates the need for installing each refrigerant connection pipe upward, such as along a wall surface of the room to the indoor units (first indoor unit 6, second indoor unit 7, third indoor unit 8, fourth indoor unit 9), and makes it possible to make each refrigerant connection pipe inconspicuous indoors.
In general, as the pipe diameter increases, the bending radius required for bending while suppressing damage tends to be large. In contrast, in the outdoor unit 2 of the second embodiment, the first gas-side shutoff valve 18a to which the first gas-side refrigerant connection pipe 66 having the largest pipe diameter is connected, the third gas-side shutoff valve 28a to which the third gas-side refrigerant connection pipe 86 having the second largest pipe diameter is connected, the second gas-side shutoff valve 18b to which the second gas-side refrigerant connection pipe 76 having the third largest pipe diameter is connected, and the fourth gas-side shutoff valve 28b to which the fourth gas-side refrigerant connection pipe 96 having the smallest pipe diameter is connected are arranged in order from the bottom. Therefore, the gas-side refrigerant connection pipe having a relatively large pipe diameter can secure a wider space for the curved portion, and can secure a large bending radius. This makes it possible to improve the workability when each gas-side refrigerant connection pipe is bent and connected to the gas-side shutoff valve.
The heat transfer fins 33 of the outdoor heat exchanger 30 are attached such that the plurality of first heat transfer tubes 31 belonging to the first refrigerant circuit 10 and the plurality of second heat transfer tubes 32 belonging to the second refrigerant circuit 20 penetrate. This allows the outdoor heat exchanger 30 to give and receive heat between the refrigerant flowing through the first refrigerant circuit 10 and the refrigerant flowing through the second refrigerant circuit 20, via the heat transfer fins 33 to which both the first heat transfer tubes 31 and the second heat transfer tubes 32 are attached. This makes it possible to use the capacity of one refrigerant circuit by the other refrigerant circuit between the first refrigerant circuit 10 and the second refrigerant circuit 20. For example, when the cooling operation is executed in the first refrigerant circuit 10 and the heating operation is executed in the second refrigerant circuit 20 simultaneously by using the first indoor unit 6 and the second indoor unit 7 belonging to the first refrigerant circuit 10 for cooling a computer room or the like, it is possible to increase both the cooling capacity of the first refrigerant circuit 10 and the heating capacity of the second refrigerant circuit 20 by giving and receiving heat between the first refrigerant circuit 10 and the second refrigerant circuit 20 in the outdoor heat exchanger 30.
(9) Modifications of Second Embodiment
(9-1) Modification A of Second Embodiment
The second embodiment has described, as an example, the case where R32, which is not a non-azeotropic mixed refrigerant, is used in the first refrigerant circuit 10 and the second refrigerant circuit 20.
In contrast, a non-azeotropic mixed refrigerant, which is a refrigerant classified by ISO817 as lower flammability (A2L), may be used with the amount of charged refrigerant of less than 1.84 kg in each of the first refrigerant circuit 10 and the second refrigerant circuit 20. Examples of the non-azeotropic mixed refrigerant include R454A, R454B, and R454C.
(9-2) Modification B of Second Embodiment
The second embodiment described above has described, as an example, the case where the first gas-side shutoff valve 18a to which the first gas-side refrigerant connection pipe 66 belonging to the first refrigerant circuit 10 is connected, the third gas-side shutoff valve 28a to which the third gas-side refrigerant connection pipe 86 belonging to the second refrigerant circuit 20 is connected, the second gas-side shutoff valve 18b to which the second gas-side refrigerant connection pipe 76 belonging to the first refrigerant circuit 10 is connected, and the fourth gas-side shutoff valve 28b to which the fourth gas-side refrigerant connection pipe 96 belonging to the second refrigerant circuit 20 is connected are arranged in order from the bottom.
In contrast, for example, as shown in
In this case, for example, when the cooling operation is executed in the first refrigerant circuit 10 and the heating operation is executed in the second refrigerant circuit 20 simultaneously, or when the heating operation is executed in the first refrigerant circuit 10 and the cooling operation is executed in the second refrigerant circuit 20 simultaneously, it is possible to suppress the giving and receiving of air between the first gas-side shutoff valve 18a, the third gas-side shutoff valve 28a, the fourth gas-side shutoff valve 28b, and the second gas-side shutoff valve 18b, and heat via the shutoff valve support plate 42, and to improve the efficiency.
For example, the case where the cooling operation is executed in the first refrigerant circuit 10 and the heating operation is executed in the second refrigerant circuit 20 will be described. To begin with, the temperature of the second gas-side shutoff valve 18b is decreased by the refrigerant whose temperature has decreased due to evaporation in the indoor heat exchanger 71. The temperatures of the third gas-side shutoff valve 28a and the fourth gas-side shutoff valve 28b are increased by the high-temperature refrigerant discharged from the second compressor 21. The low-temperature second gas-side shutoff valve 18b is not arranged at a position between the high-temperature third gas-side shutoff valve 28a and the high-temperature fourth gas-side shutoff valve 28b, but is arranged at a position far above the high-temperature third gas-side shutoff valve 28a and near the high-temperature fourth gas-side shutoff valve 28b only. This makes it possible to prevent a bad influence of a decrease in the temperature of both the third gas-side shutoff valve 28a and the fourth gas-side shutoff valve 28b by the low-temperature second gas-side shutoff valve 18b, and to limit the influence of the low-temperature second gas-side shutoff valve 18b to only the third gas-side shutoff valve 28a. This makes it possible to deliver the refrigerant discharged from the second compressor 21 during the heating operation to the third indoor heat exchanger 81 while keeping the temperature high.
(9-3) Modification C of Second Embodiment
The second embodiment has described, as an example, the case where the air conditioning apparatus 1 of the second embodiment described above is provided with two refrigerant circuits independent of each other and two indoor units are connected to each refrigerant circuit.
However, the number of refrigerant circuits independent of each other included in the air conditioning apparatus is not limited to two, and may be three or more.
The number of indoor units per one refrigerant circuit is not limited to two, and may be one, or three or more.
The type of pipe diameter of the gas refrigerant connection pipe included in one refrigerant circuit is not limited to two, and may be three or more.
(9-4) Modification D of Second Embodiment
The application of the first indoor unit 6, the second indoor unit 7, the third indoor unit 8, and the fourth indoor unit 9 in the second embodiment described above is not limited to air conditioning applications, nor is it limited to those commonly used in one type of application. These units may be used, for example, not only for air conditioning applications, but also for water heater applications and floor heating applications, and may be used in combination thereof.
(10) Configuration of Air Conditioning Apparatus of Third Embodiment
An air conditioning apparatus of the third embodiment is almost the same as the air conditioning apparatus of the first embodiment, and differences will be mainly described below.
In the air conditioning apparatus of the third embodiment, pipes having pipe diameters according to the capacity of indoor heat exchangers 61, 71, 81, and 91 included in indoor units 6 to 9 to be connected are used for a first liquid-side refrigerant connection pipe 65, a second liquid-side refrigerant connection pipe 75, a third liquid-side refrigerant connection pipe 85, and a fourth liquid-side refrigerant connection pipe 95, respectively. Note that the pipe diameter of each liquid-side refrigerant connection pipe is smaller than the pipe diameter of paired gas-side refrigerant connection pipe for each indoor unit.
Pipes having pipe diameters according to the capacity of the indoor heat exchangers 61, 71, 81, and 91 included in the indoor units 6 to 9 to be connected are used for a first gas-side refrigerant connection pipe 66, a second gas-side refrigerant connection pipe 76, a third gas-side refrigerant connection pipe 86, and a fourth gas-side refrigerant connection pipe 96, respectively. In particular, in the third embodiment, the pipe diameter of the first gas-side refrigerant connection pipe 66 differs from the pipe diameter of the second gas-side refrigerant connection pipe 76. The pipe diameter of the first gas-side refrigerant connection pipe 66 is larger than the pipe diameter of the second gas-side refrigerant connection pipe 76. The pipe diameter of the third gas-side refrigerant connection pipe 86 differs from the pipe diameter of the fourth gas-side refrigerant connection pipe 96. The pipe diameter of the third gas-side refrigerant connection pipe 86 is larger than the pipe diameter of the fourth gas-side refrigerant connection pipe 96. In the third embodiment, the pipe diameter of the first gas-side refrigerant connection pipe 66 is larger than the pipe diameter of the third gas-side refrigerant connection pipe 86, the pipe diameter of the third gas-side refrigerant connection pipe 86 is larger than the pipe diameter of the second gas-side refrigerant connection pipe 76, and the pipe diameter of the second gas-side refrigerant connection pipe 76 is larger than the pipe diameter of the fourth gas-side refrigerant connection pipe 96.
(10-1) Outdoor Unit
In an outdoor unit 2 of the air conditioning apparatus 1 of the third embodiment, the capacity of a first compressor 11 of a first refrigerant circuit 10 and the capacity of a second compressor 21 of a second refrigerant circuit 20 differ from each other. Specifically, in the third embodiment, the capacity of the first compressor 11 is larger than the capacity of the second compressor 21. Note that the capacity of a compressor, for example, the capacity of a compressor of variable capacity can be obtained by comparison of the cylinder volume.
(10-2) Indoor Unit
The first indoor unit 6, the second indoor unit 7, the third indoor unit 8, and the fourth indoor unit 9 of the air conditioning apparatus 1 of the third embodiment are similar to respective indoor units of the first embodiment described above.
(10-3) Control Unit
A control unit 50 of the air conditioning apparatus 1 of the third embodiment is similar to the control unit of the first embodiment described above. Note that in the third embodiment, when instructions of cooling operation or heating operation are received from a first remote control device 63 or a second remote control device 73 corresponding to the first refrigerant circuit 10, and when instructions of heating operation or cooling operation are received from a third remote control device 83 or a fourth remote control device 93 corresponding to the second refrigerant circuit 20, the control unit 50 executes the cooling operation and the heating operation simultaneously in the first refrigerant circuit 10 and the second refrigerant circuit 20.
(11) Configuration of Outdoor Heat Exchanger
An outdoor heat exchanger 30 of the air conditioning apparatus 1 of the third embodiment is almost similar to the outdoor heat exchanger of the first embodiment described above, but unlike the first embodiment, part of the plurality of first heat transfer tubes 31 is arranged such that the first heat transfer tubes 31 overlap each other in the air flow direction near an upper end of the outdoor heat exchanger 30 in the third embodiment.
As shown in
As shown in
In the third embodiment, the outdoor heat exchanger 30 and an outdoor fan 30a are provided such that the direction of the refrigerant flow in the outdoor heat exchanger 30 is parallel to the direction of the air flow supplied from the outdoor fan 30a to the outdoor heat exchanger 30, when the first refrigerant circuit 10 and the second refrigerant circuit 20 are both in the heating operation state as shown in the refrigerant flow of the heating operation state in
(12) Characteristics of Third Embodiment
The air conditioning apparatus 1 of the third embodiment includes the plurality of indoor units: the first indoor unit 6, the second indoor unit 7, the third indoor unit 8, and the fourth indoor unit 9, and can process the heat load at the place where each indoor unit is disposed. Here, the air conditioning apparatus 1 processes the heat load at a plurality of places by using the plurality of refrigerant circuits independent of each other, the first refrigerant circuit 10 and the second refrigerant circuit 20. In this way, by processing the heat load at a plurality of places by using the plurality of refrigerant circuits, it is possible to keep the amount of refrigerant charged into one refrigerant circuit to a lower level than the case of using one refrigerant circuit, and specifically, to keep the amount of refrigerant charged into one refrigerant circuit to less than 1.84 kg.
Therefore, even if R32, which is a refrigerant classified by ISO817 as lower flammability (A2L), is charged into each of the first refrigerant circuit 10 and the second refrigerant circuit 20, it is possible to keep the amount of refrigerant leak to a low level when a refrigerant leak occurs in either the first refrigerant circuit 10 or the second refrigerant circuit 20. Therefore, even if a refrigerant leak occurs, it is possible to keep the combustion possibility to a low level.
In the air conditioning apparatus 1 of the third embodiment, in the first refrigerant circuit 10 including the first compressor 11, which is a compressor having large capacity, the first gas-side refrigerant connection pipe 66 having the largest pipe diameter is used, out of the plurality of gas-side refrigerant connection pipes included in the air conditioning apparatus 1. This makes it possible to assign the gas-side refrigerant connection pipe having a pipe diameter commensurate with the capacity of the compressor of each refrigerant circuit, and to inhibit the pipe size from becoming too large or too small, thereby making it possible to improve the operating efficiency of each refrigerant circuit. Furthermore, in the air conditioning apparatus 1 of the third embodiment, in the second refrigerant circuit 20 including the second compressor 21, which is a compressor having small capacity, the fourth gas-side refrigerant connection pipe 96 having the smallest pipe diameter is used, out of the plurality of gas-side refrigerant connection pipes included in the air conditioning apparatus 1. This also improves the operating efficiency of the air conditioning apparatus 1.
Furthermore, in the air conditioning apparatus 1 of the third embodiment, the pipe diameter of the first gas-side refrigerant connection pipe 66 of the first refrigerant circuit 10 is larger than the pipe diameter of the third gas-side refrigerant connection pipe 86 of the second refrigerant circuit 20, and the pipe diameter of the second gas-side refrigerant connection pipe 76 of the first refrigerant circuit 10 is larger than the pipe diameter of the fourth gas-side refrigerant connection pipe 96 of the second refrigerant circuit 20. That is, the sum of the pipe diameters of the plurality of gas-side refrigerant connection pipes included in the first refrigerant circuit 10 is larger than the sum of the pipe diameters of the plurality of gas-side refrigerant connection pipes included in the second refrigerant circuit 20. This allows the air conditioning apparatus 1 to make the sum of the pipe diameters of the plurality of gas-side refrigerant connection pipes included in the first refrigerant circuit 10 including the first compressor 11, which is a compressor having large capacity, larger than the sum of the pipe diameters of the plurality of gas-side refrigerant connection pipes included in the first refrigerant circuit 10 including the second compressor 21, which is a compressor having small capacity. This also makes it possible to assign the sum of the pipe diameters commensurate with the capacity of the compressor of each refrigerant circuit, and to inhibit the total pipe size from becoming too large or too small, thereby improving the operating efficiency of the air conditioning apparatus 1.
The outdoor heat exchanger 30 of the air conditioning apparatus 1 has a configuration in which the number of first heat transfer tubes 31 belonging to the first refrigerant circuit 10 including the first compressor 11, which is a compressor having large capacity, is larger than the number of second heat transfer tubes 32 belonging to the second refrigerant circuit 20 including the second compressor 21, which is a compressor having small capacity. This makes it possible to distribute the capacity of the outdoor heat exchanger 30 according to the capacity of the compressor in each refrigerant circuit.
The heat transfer fins 33 of the outdoor heat exchanger 30 are attached such that the plurality of first heat transfer tubes 31 belonging to the first refrigerant circuit 10 and the plurality of second heat transfer tubes 32 belonging to the second refrigerant circuit 20 penetrate. This allows the outdoor heat exchanger 30 to give and receive heat between the refrigerant flowing through the first refrigerant circuit 10 and the refrigerant flowing through the second refrigerant circuit 20, via the heat transfer fins 33 to which both the first heat transfer tubes 31 and the second heat transfer tubes 32 are attached. In particular, in the outdoor heat exchanger 30 of the third embodiment, for example, unlike the case where the heat transfer tubes are provided in only one row in the air flow direction, many places are secured where the plurality of first heat transfer tubes 31 belonging to the first refrigerant circuit 10 and the plurality of second heat transfer tubes 32 belonging to the second refrigerant circuit 20 are arranged adjacent to each other. Specifically, in the outdoor heat exchanger 30 of the third embodiment, below the portion near the upper end of the outdoor heat exchanger 30, places where the first heat transfer tubes 31 and the second heat transfer tubes 32 are located within a distance range of equal to or less than twice the closest pitch of the plurality of first heat transfer tubes 31 arranged vertically are secured in half or more of the total number of plurality of first heat transfer tubes 31, enabling sufficient giving and receiving of heat between the refrigerant flowing through the first refrigerant circuit 10 and the refrigerant flowing through the second refrigerant circuit 20. This makes it possible to use the capacity of one refrigerant circuit by the other refrigerant circuit between the first refrigerant circuit 10 and the second refrigerant circuit 20. For example, when the cooling operation is executed in the first refrigerant circuit 10 and the heating operation is executed in the second refrigerant circuit 20 simultaneously by using the first indoor unit 6 and the second indoor unit 7 belonging to the first refrigerant circuit 10 for cooling a computer room or the like, it is possible to increase both the cooling capacity of the first refrigerant circuit 10 and the heating capacity of the second refrigerant circuit 20 by giving and receiving heat between the first refrigerant circuit 10 and the second refrigerant circuit 20 in the outdoor heat exchanger 30.
(13) Modifications of Third Embodiment
(13-1) Modification A of Third Embodiment
The third embodiment has described, as an example, the case where R32, which is not a non-azeotropic mixed refrigerant, is used in the first refrigerant circuit 10 and the second refrigerant circuit 20.
In contrast, a non-azeotropic mixed refrigerant, which is a refrigerant classified by ISO817 as lower flammability (A2L), may be used with the amount of charged refrigerant of less than 1.84 kg in each of the first refrigerant circuit 10 and the second refrigerant circuit 20. Examples of the non-azeotropic mixed refrigerant include R454A, R454B, and R454C.
(13-2) Modification B of Third Embodiment
The third embodiment described above has described, as an example, the case where the pipe diameters of the gas-side refrigerant connection pipes of the air conditioning apparatus 1 differ from each other.
In contrast, in the air conditioning apparatus 1, the plurality of gas-side refrigerant connection pipes included in the first refrigerant circuit 10 may all have the same pipe diameter, and the plurality of gas-side refrigerant connection pipes included in the second refrigerant circuit 20 may all have the same pipe diameter.
Furthermore, all the plurality of gas-side refrigerant connection pipes included in the air conditioning apparatus 1 may have the same pipe diameter. Note that in the configuration of this case, the number of gas-side refrigerant connection pipes included in the refrigerant circuit including the compressor having the maximum capacity is larger than the number of gas-side refrigerant connection pipes included in the other refrigerant circuit.
(13-3) Modification C of Third Embodiment
The air conditioning apparatus 1 of the third embodiment described above has been described by taking the case, as an example, where, when instructions of cooling operation or heating operation are received from the first remote control device 63 or the second remote control device 73 corresponding to the first refrigerant circuit 10, and when instructions of heating operation or cooling operation are received from the third remote control device 83 or the fourth remote control device 93 corresponding to the second refrigerant circuit 20, the control unit 50 executes the cooling operation and the heating operation simultaneously in the first refrigerant circuit 10 and the second refrigerant circuit 20.
In contrast, the condition for simultaneously executing the cooling operation and the heating operation in the first refrigerant circuit 10 and the second refrigerant circuit 20 is not limited to such setting by the remote control devices.
For example, the control unit 50 may store a predetermined load reference condition in a memory or the like in advance, and determine whether the load to be processed by the indoor unit belonging to the refrigerant circuit in operation exceeds the predetermined load reference condition when only one of the first refrigerant circuit 10 and the second refrigerant circuit 20 is in operation. When it is determined that the load exceeds the predetermined load reference condition, the control unit 50 may start the operation of the refrigerant circuit out of operation differently from the refrigerant circuit in operation, thereby causing the refrigerant circuit out of operation to support the load processing on the refrigerant circuit side in operation. Specifically, for example, when the heating operation is executed in the first refrigerant circuit 10 and the load processed by the first indoor unit 6 or the second indoor unit 7 exceeds the predetermined load reference condition, the cooling operation may be started in the second refrigerant circuit 20 out of operation, thereby increasing the evaporation efficiency of the refrigerant flowing through the first refrigerant circuit 10 of the outdoor heat exchanger 30.
(13-4) Modification D of Third Embodiment
The air conditioning apparatus 1 of the third embodiment described above has been described by taking, as an example, the case where two refrigerant circuits independent of each other are provided and two indoor units are connected to each refrigerant circuit.
However, the number of refrigerant circuits independent of each other included in the air conditioning apparatus is not limited to two, and may be three or more.
The number of indoor units per one refrigerant circuit is not limited to two, and may be one, or three or more.
The type of pipe diameter of the gas refrigerant connection pipe included in one refrigerant circuit is not limited to two, and may be three or more.
(13-5) Modification E of Third Embodiment
The application of the first indoor unit 6, the second indoor unit 7, the third indoor unit 8, and the fourth indoor unit 9 in the third embodiment described above is not limited to air conditioning applications, nor is it limited to those commonly used in one type of application. These units may be used, for example, not only for air conditioning applications, but also for water heater applications and floor heating applications, and may be used in combination thereof.
(Note)
Note that in the heat source-side heat exchanger, at least two or more of the plurality of second heat transfer tubes may be arranged on a downwind side of any one of the plurality of first heat transfer tubes, and at least two or more of the plurality of first heat transfer tubes may be arranged on a windward side of any one of the plurality of second heat transfer tubes. In the heat source-side heat exchanger, there may be no second heat transfer tube arranged on a windward side of the plurality of first heat transfer tubes.
Note that the first heat transfer tubes and the second heat transfer tubes may be arranged to overlap each other or may be arranged not to overlap each other in the air flow direction.
Note that half or more of the plurality of first heat transfer tubes may be arranged on a windward side of any one of the plurality of second heat transfer tubes.
Note that the heat source-side unit may be commonly used in the plurality of refrigerant circuits. The heat source-side unit commonly used in the plurality of refrigerant circuits can be the heat source-side unit including part of each of the refrigerant circuits independent of each other. For example, the heat source-side unit may include each heat source-side heat exchanger belonging to each refrigerant circuit and be unitized, or may include a compressor belonging to each refrigerant circuit and be unitized. Here, when the heat source-side unit includes each heat source-side heat exchanger belonging to each refrigerant circuit and is unitized, each heat source-side heat exchanger belonging to each refrigerant circuit may be a separate heat exchanger having separate heat transfer fin, or the heat source-side heat exchanger belonging to each refrigerant circuit may include a common heat transfer fin.
Note that when the plurality of refrigerant circuits of the refrigerant cycle system includes a plurality of pipes having a pipe diameter smaller than the pipe diameter of the “two high-ranking pipes having a large pipe diameter”, the plurality of pipes having a small pipe diameter may be separated into two or more refrigerant circuits.
Note that out of the plurality of gas refrigerant connection pipes, when a plurality of “two high-ranking pipes having a large pipe diameter” that have the second largest pipe diameter is present, an arbitrary one of the pipes can correspond to the “two high-ranking pipes having a large pipe diameter”.
Note that out of the plurality of gas refrigerant connection pipes, when a plurality of “two low-ranking pipes having a small pipe diameter” that has the second smallest pipe diameter is present, an arbitrary one of the pipes can correspond to the “two low-ranking pipes having a small pipe diameter”.
Note that the shutoff valve of the gas refrigerant connection pipe having the minimum pipe diameter and included in the second refrigerant circuit, the shutoff valve of the gas refrigerant connection pipe having the minimum pipe diameter and included in the first refrigerant circuit, the shutoff valve of the gas refrigerant connection pipe having the maximum pipe diameter and included in the second refrigerant circuit, and the shutoff valve of the gas refrigerant connection pipe having the maximum pipe diameter and included in the first refrigerant circuit may be arranged in line in order from the top without any other shutoff valve that lies between the shutoff valves, or may be arranged in line in order from the top while another shutoff valve lies between the shutoff valves.
Note that the shutoff valve of the gas refrigerant connection pipe having the minimum pipe diameter and included in the first refrigerant circuit, the shutoff valve of the gas refrigerant connection pipe having the minimum pipe diameter and included in the second refrigerant circuit, the shutoff valve of the gas refrigerant connection pipe having the maximum pipe diameter and included in the second refrigerant circuit, and the shutoff valve of the gas refrigerant connection pipe having the maximum pipe diameter and included in the first refrigerant circuit may be arranged in line in order from the top without any other shutoff valve that lies between the shutoff valves, or may be arranged in line in order from the top while another shutoff valve lies between the shutoff valves.
Note that the heat source-side unit may be commonly used in the first refrigerant circuit and the second refrigerant circuit. The heat source-side unit commonly used in the first refrigerant circuit and the second refrigerant circuit is the heat source-side unit including part of each of the first refrigerant circuit and the second refrigerant circuit independent of each other, and for example, may be obtained by unitizing the heat source-side heat exchanger belonging to the first refrigerant circuit and the heat source-side heat exchanger belonging to the second refrigerant circuit, or may be obtained by unitizing the compressor belonging to the first refrigerant circuit and the compressor belonging to the second refrigerant circuit. Here, the heat source-side heat exchanger belonging to the first refrigerant circuit and the heat source-side heat exchanger belonging to the second refrigerant circuit may be separate heat exchangers having separate heat transfer fins, or the heat source-side heat exchangers may have a common heat transfer fin.
Note that if a plurality of “gas refrigerant connection pipes having the maximum pipe diameter” is present in the refrigerant cycle system, an arbitrary one of the pipes can correspond to the “gas refrigerant connection pipe having the maximum pipe diameter”.
The first compressor may be a compressor having the largest capacity of the plurality of compressors provided in the refrigerant cycle system. If a plurality of “compressors having the maximum capacity” is present in the refrigerant cycle system, an arbitrary one of the compressors can correspond to the “compressor having the maximum capacity”.
Note that the sum of pipe diameters of the gas refrigerant connection pipes connected to the refrigerant circuit including the compressor having the maximum capacity in the refrigerant cycle system may be larger than the sum of pipe diameters of the gas refrigerant connection pipes connected to the refrigerant circuit including the compressor other than the compressor having the maximum capacity in the refrigerant cycle system. Here, when the plurality of refrigerant circuits including the compressor having the maximum capacity is present, the “sum of pipe diameters of the gas refrigerant connection pipes” may be an average of the sum of pipe diameters of the gas refrigerant connection pipes in each refrigerant circuit including the compressor having the maximum capacity. The average may be compared with the sum of pipe diameters of the gas refrigerant connection pipes connected to the refrigerant circuit including the compressor other than the compressor having the maximum capacity in each refrigerant circuit including the compressor other than the compressor having the maximum capacity.
Note that the heat source-side unit may be commonly used in the first refrigerant circuit and the second refrigerant circuit. The heat source-side unit commonly used in the first refrigerant circuit and the second refrigerant circuit is the heat source-side unit including part of each of the first refrigerant circuit and the second refrigerant circuit independent of each other, and for example, may be obtained by unitizing the heat source-side heat exchanger belonging to the first refrigerant circuit and the heat source-side heat exchanger belonging to the second refrigerant circuit, or may be obtained by unitizing the compressor belonging to the first refrigerant circuit and the compressor belonging to the second refrigerant circuit.
Note that the refrigerant cycle system does not have to include two or more types of pipe diameter as the plurality of gas refrigerant connection pipes, and the pipe diameter of all the gas refrigerant connection pipes may be the same.
Note that the sum of pipe diameters of the gas refrigerant connection pipes connected to the refrigerant circuit including the compressor having the maximum capacity in the refrigerant cycle system may be larger than the sum of pipe diameters of the gas refrigerant connection pipes connected to the refrigerant circuit including the compressor other than the compressor having the maximum capacity in the refrigerant cycle system. Here, when the plurality of refrigerant circuits including the compressor having the maximum capacity is present, the “sum of pipe diameters of the gas refrigerant connection pipes” may be an average of the sum of pipe diameters of the gas refrigerant connection pipes in each refrigerant circuit including the compressor having the maximum capacity. The average may be compared with the sum of pipe diameters of the gas refrigerant connection pipes connected to the refrigerant circuit including the compressor other than the compressor having the maximum capacity in each refrigerant circuit including the compressor other than the compressor having the maximum capacity.
The first compressor may be a compressor having the largest capacity of the plurality of compressors provided in the refrigerant cycle system. If a plurality of “compressors having the maximum capacity” is present in the refrigerant cycle system, an arbitrary one of the compressors can correspond to the “compressor having the maximum capacity”.
Note that the heat source-side heat exchanger common to the first refrigerant circuit and the second refrigerant circuit can be, for example, a heat source-side heat exchanger in which the refrigerant flow path flowing through part of the first refrigerant circuit and the refrigerant flow path flowing through part of the second refrigerant circuit are coupled via the common heat transfer fin.
Note that the first heat transfer tubes and the second heat transfer tubes may be arranged to overlap each other or may be arranged not to overlap each other in the air flow direction.
Note that in the heat source-side heat exchanger, at least two or more of the plurality of second heat transfer tubes may be arranged on a downwind side of any one of the plurality of first heat transfer tubes, and at least two or more of the plurality of first heat transfer tubes may be arranged on a windward side of any one of the plurality of second heat transfer tubes. In the heat source-side heat exchanger, there may be no second heat transfer tube arranged on a windward side of the plurality of first heat transfer tubes.
(Supplementary Note)
Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present disclosure. Accordingly, the scope of the disclosure should be limited only by the attached claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-212279 | Nov 2019 | JP | national |
| 2019-212280 | Nov 2019 | JP | national |
| 2019-212281 | Nov 2019 | JP | national |
This is a continuation application of International Patent Application No. PCT/JP2020/043435, filed on Nov. 20, 2020, and claims priority to Japanese Patent Application No. 2019-212279, filed on Nov. 25, 2019, Japanese Patent Application No. 2019-212280, filed on Nov. 25, 2019, and Japanese Patent Application No. 2019-212281, filed on Nov. 25, 2019. The content of these priority applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2020/043435 | Nov 2020 | US |
| Child | 17726006 | US |
