Patent Grant
10627127
This application is a U.S. national stage application of International Application No. PCT/JP2015/081827, filed on Nov. 12, 2015, the contents of which are incorporated herein by reference.
The present invention relates to an air conditioner, and in particular to an air conditioner which uses a refrigerant having flammability.
Conventionally, an anticorrosion layer is formed on an outer circumferential surface of a pipe in which refrigerant flows in an air conditioner, in order to prevent refrigerant leakage due to corrosion of the pipe.
Japanese Patent Laying-Open No. 2014-20704 (PTD 1) discloses a bonded body of pipe members, including an inner fitting pipe member and an outer fitting pipe member bonded by brazing, each outer circumferential surface of the inner fitting pipe member and the outer fitting pipe member having an anticorrosion layer formed thereon. A base material of the inner fitting pipe member and the outer fitting pipe member is made of aluminum or an aluminum alloy, and a predetermined amount of zinc, which has a potential lower than that of aluminum serving as the base material (which is more likely to corrode than aluminum), is mixed into the anticorrosion layer.
In addition, in a conventional air conditioner, since corrosion of a pipe is more likely to proceed in particular in an outside of a room, the thickness of a pipe placed in the outside of the room is provided to be equal to or more than the thickness of a pipe placed in the room. It should be noted that the thickness of a pipe used herein means a total thickness of a base material and an anticorrosion layer.
PTD 1: Japanese Patent Laying-Open No. 2014-20704
In the conventional air conditioner, however, it is difficult to use a refrigerant having flammability (hereinafter referred to as a flammable refrigerant).
Specifically, when a flammable refrigerant is used for an air conditioner, it is required to reliably prevent leakage thereof in a room, rather than in an outside of the room. This is because, in the room in which, for example, a kitchen and the like are placed, there are more instruments and the like which may become a source of ignition than those in the outside of the room, and because the room is a closed space and a leaking refrigerant is likely to stagnate therein.
However, the conventional air conditioner does not assume use of such a flammable refrigerant, and anticorrosion design or pressure resistant design for suppressing refrigerant leakage in a room has not been made satisfactorily.
The present invention has been made to solve the aforementioned problem. A main object of the present invention is to provide an air conditioner which can suppress refrigerant leakage in a room and has a high safety even when using a flammable refrigerant.
An air conditioner in accordance with the present invention includes an indoor apparatus placed in a room, and an outdoor apparatus placed in an outside of the room separated from the room by a wall. The indoor apparatus includes a first refrigerant pipe in which a flammable refrigerant flows. The outdoor apparatus includes a second refrigerant pipe in which the flammable refrigerant flows. The first refrigerant pipe and the second refrigerant pipe are connected to each other to constitute a refrigerant flow path in which the flammable refrigerant is enclosed. The second refrigerant pipe has a portion smaller in thickness than a minimum-thickness portion of the first refrigerant pipe.
According to the present invention, an air conditioner which can suppress refrigerant leakage in a room and has a high safety even when using a flammable refrigerant can be provided.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that, in the drawings below, identical or corresponding parts will be designated by the same reference numerals, and the description thereof will not be repeated.
<Configuration of Air Conditioner>
An air conditioner 100 in accordance with a first embodiment will be described with reference to
In such an air conditioner 100, also at the time of use after a predetermined period has passed from the beginning of use, the thinner portion of second refrigerant pipe 4 (when the thickness varies in the thinner portion, a minimum-thickness portion thereof) serves as a minimum-thickness portion in the refrigerant pipes of air conditioner 100. Accordingly, even when air conditioner 100 is used until the refrigerant leaks from a refrigerant pipe damaged by corrosion, the refrigerant leakage occurs at the minimum-thickness portion of second refrigerant pipe 4 placed in the outside of the room. If second refrigerant pipe 4 is damaged and the refrigerant leaks in an amount more than a predetermined amount, air conditioner 100 becomes unusable. As a result, air conditioner 100 suppresses refrigerant leakage from first refrigerant pipe 3 placed in the room, and can safely use the flammable refrigerant as a heat medium, irrespective of the use period.
The thickness of the thinner portion of second refrigerant pipe 4 is, for example, more than or equal to a thickness which can prevent refrigerant leakage due to corrosion within a standard use period designed for air conditioner 100 (design standard use period). Thereby, air conditioner 100 can suppress occurrence of refrigerant leakage within the design standard use period. When air conditioner 100 is used for more than the design standard use period, no through hole is formed in first refrigerant pipe 3 before a through hole penetrating the inside and the outside of second refrigerant pipe 4 is formed in the thinner portion of second refrigerant pipe 4. Accordingly, air conditioner 100 can suppress occurrence of refrigerant leakage in the room even when it is used for more than the standard use period. It should be noted that refrigerant leakage in second refrigerant pipe 4 can be detected by any method (the details will be described later). Therefore, for air conditioner 100, an action such as replacement of air conditioner 100 can be taken at the timing when refrigerant leakage in second refrigerant pipe 4 is detected, for example.
Next, a specific example of air conditioner 100 in accordance with the first embodiment will be described with reference to
As shown in
As shown in
As shown in
As shown in
As shown in
As shown in
As shown in
Base materials 31, 33, 41, 43, and 45 have inner circumferential surfaces in contact with the flammable refrigerant, and outer circumferential surfaces in contact with anticorrosion layers 32, 34, 42, 44, and 46. Anticorrosion layers 32, 34, 42, 44, and 46 are provided on the outer circumferential surfaces of base materials 31, 33, 41, 43, and 45 to surround base materials 31, 33, 41, 43, and 45, respectively. Anticorrosion layers 32, 34, 42, 44, and 46 have inner circumferential surfaces in contact with base materials 31, 33, 41, 43, and 45, and outer circumferential surfaces in contact with the atmosphere in the room or in the outside of the room. The outer circumferential surfaces of base materials 31 and 33 are separated from the atmosphere in the room by anticorrosion layers 32 and 34, respectively. The outer circumferential surfaces of anticorrosion layers 32 and 34 are in contact with the atmosphere in the room. The outer circumferential surfaces of anticorrosion layers 42, 44, and 46 are in contact with the atmosphere in the outside of the room. The outer circumferential surfaces of base materials 41, 43, and 45 are separated from the atmosphere in the outside of the room by anticorrosion layers 42, 44, and 46, respectively. A material constituting base materials 31, 33, 41, 43, and 45 includes at least one of aluminum (Al) and copper (Cu), for example. A material constituting anticorrosion layers 32, 34, 42, 44, and 46 may be any material which includes a material having a standard electrode potential lower than (an ionization tendency higher than) that of the material constituting base materials 31, 33, 41, 43, and 45, and includes at least one selected from the group consisting of zinc (Zn), Al, and cadmium (Cd), for example. That is, anticorrosion layers 32, 34, 42, 44, and 46 are constituted of a material which is more likely to corrode than the material constituting base materials 31, 33, 41, 43, and 45. Anticorrosion layers 32, 34, 42, 44, and 46 may be constituted by winding a tape having an anticorrosion material applied thereto (for example, a Zn-sprayed tape) around base materials 31, 33, 41, 43, and 45. The anticorrosion material applied to the tape includes at least one selected from the group consisting of Zn, Al, and Cd. In this case, thicknesses si1, si2, so1, so2, and so3 of anticorrosion layers 32, 34, 42, 44, and 46 (see
The minimum-thickness portion of first refrigerant pipe 3 is provided in at least one of the plurality of indoor heat transfer pipes 12, for example. A thickness ui1 of the plurality of indoor heat transfer pipes 12 (see
Thickness ui1 of indoor heat transfer pipe 12 is the sum of a thickness ti1 of base material 31 (see
The minimum-thickness portion of second refrigerant pipe 4 is provided in connecting pipes 6 and 7, for example. A thickness uo1 of connecting pipes 6 and 7 (see
Thickness uo1 of connecting pipes 6 and 7 is more than or equal to a thickness which can prevent refrigerant leakage due to corrosion within the design standard use period for air conditioner 100. In other words, thickness uo1 of connecting pipes 6 and 7 is provided to be thicker than a corrosion amount (an amount of reduction in thickness) of connecting pipes 6 and 7 estimated in the design standard use period for air conditioner 100. Thickness uo2 of outdoor heat transfer pipe 22 is provided to be thicker than a corrosion amount of outdoor heat transfer pipe 22 estimated in the design standard use period for air conditioner 100. Thickness uo3 of outdoor pipes 23 to 28 is provided to be thicker than a corrosion amount of outdoor pipes 23 to 28 estimated in the design standard use period for air conditioner 100.
Thickness uo1 of connecting pipes 6 and 7 is the sum of a thickness to1 of base material 41 and thickness so1 of anticorrosion layer 42. Thickness uo2 of outdoor heat transfer pipe 22 is the sum of a thickness to2 of base material 43 and thickness so2 of anticorrosion layer 44. Thickness uo3 of outdoor pipes 23 to 28 is the sum of a thickness to3 of base material 45 and thickness so3 of anticorrosion layer 46.
Thickness to1 of base material 41 of connecting pipes 6 and 7 is equal to thickness to2 of base material 43 of outdoor heat transfer pipe 22, for example. Thickness so1 of anticorrosion layer 42 of connecting pipes 6 and 7 is thinner than thickness so2 of anticorrosion layer 44 of outdoor heat transfer pipe 22, for example. Thickness to2 of base material 43 of outdoor heat transfer pipe 22 is equal to thickness to3 of base material 45 of outdoor pipes 23 to 28, for example. Thickness so2 of anticorrosion layer 44 of outdoor heat transfer pipe 22 is equal to thickness so3 of anticorrosion layer 46 of outdoor pipes 23 to 28, for example. Thickness uo2 of outdoor heat transfer pipe 22 is a distance between an inner circumferential surface of outdoor heat transfer pipe 22 in contact with the flammable refrigerant and an outer circumferential surface of outdoor heat transfer pipe 22, as described above. When outdoor heat transfer pipe 22 has a portion at which the distance between the inner circumferential surface and the outer circumferential surface is relatively long (a thick portion) and a portion at which the above distance is relatively short (a thin portion), thicknesses uo2, to2, and so2 respectively refer to thicknesses of outdoor heat transfer pipe 22, base material 43, and anticorrosion layer 44 at a portion at which the above distance is shortest.
The thickness of a maximum-thickness portion of second refrigerant pipe 4 (at least one of outdoor heat transfer pipe 22 and outdoor pipes 23 to 28) is less than or equal to thickness ui1 of the minimum-thickness portion of first refrigerant pipe 3 (see
Next, an exemplary operation of air conditioner 100 in accordance with the present specific example will be described. Air conditioner 100 can perform air conditioning for increasing the temperature in the room (heating operation), or air conditioning for decreasing the temperature in the room (cooling operation), for example. During the heating operation, refrigerant flow paths indicated by solid lines in
Next, the function and effect of air conditioner 100 in accordance with the present specific example will be described. In air conditioner 100, outdoor apparatus 2 includes outdoor unit 5 having outdoor heat exchanger 21 which performs heat exchange between air in the outside of the room and the flammable refrigerant. Outdoor heat exchanger 21 has outdoor heat transfer pipe 22 in which the flammable refrigerant flows. Outdoor apparatus 2 further includes connecting pipes 6 and 7 which connect outdoor heat transfer pipe 22 and first refrigerant pipe 3, and outdoor heat transfer pipe 22 and connecting pipes 6 and 7 each constitute a portion of second refrigerant pipe 4. Connecting pipes 6 and 7 have a portion smaller in thickness (the thinner portion) than the minimum-thickness portion of first refrigerant pipe 3. Thickness uo1 of connecting pipes 6 and 7 is provided to be thicker than the corrosion amount (the amount of reduction in thickness) of connecting pipes 6 and 7 estimated in the design standard use period for air conditioner 100.
Thereby, in air conditioner 100, even after a predetermined period (for example, the design standard period) has passed from the beginning of use, connecting pipe 6 or connecting pipe 7 serves as a minimum-thickness portion in the refrigerant pipes of air conditioner 100. Accordingly, air conditioner 100 can suppress occurrence of refrigerant leakage in the room within the standard use period and also after the period has passed, and has a high safety even when using the flammable refrigerant.
Further, concerning connecting pipes 6 and 7 placed in the outside of the room and placed in the outside of outdoor unit 5, a corrosion state thereof can be easily checked from the outside. Accordingly, with air conditioner 100 in accordance with the present specific example, whether there is a risk of refrigerant leakage can be easily checked through a periodical inspection and the like.
It should be noted that, for example in a case where corrosion proceeds very faster in connecting pipes 6 and 7 placed in the outside of outdoor unit 5 than in first refrigerant pipe 3 and second refrigerant pipe 4 (outdoor heat transfer pipe 22 and outdoor pipes 23 to 28) in outdoor unit 5, and it can be confirmed that corrosion of first refrigerant pipe 3 and second refrigerant pipe 4 (outdoor heat transfer pipe 22 and outdoor pipes 23 to 28) in outdoor unit 5 does not proceed at a time point when refrigerant leakage occurs in connecting pipe 6, 7, air conditioner 100 may be re-operated after connecting pipe 6, 7 is replaced. New connecting pipe 6, 7 replaced on this occasion preferably has a portion smaller in thickness than the minimum-thickness portion of first refrigerant pipe 3 at the time of replacement. Thereby, air conditioner 100 can suppress occurrence of refrigerant leakage in the room also after re-operation, and has a high safety even when using the flammable refrigerant.
While air conditioner 100 is suitable for an ordinary environment where corrosion of a refrigerant pipe is more likely to proceed in an outside of a room than in the room, air conditioner 100 is also suitable for an environment where corrosion of a refrigerant pipe is more likely to proceed in a room than in an outside of the room. In the latter case, it is only necessary that the thickness of first refrigerant pipe 3 is provided to be thicker than a corrosion amount of first refrigerant pipe 3 estimated in the design standard use period for air conditioner 100, and to be thicker than the thickness of the thinner portion (connecting pipes 6 and 7) of second refrigerant pipe 4 even after the design standard use period has passed.
Although the minimum-thickness portion of first refrigerant pipe 3 is provided in the plurality of indoor heat transfer pipes 12 in air conditioner 100 in accordance with the specific example described above, the present invention is not limited thereto. The minimum-thickness portion of first refrigerant pipe 3 may be provided in indoor pipes 13 and 14. Further, entire first refrigerant pipe 3 is provided to have a uniform thickness, and entire first refrigerant pipe 3 may be constituted as the minimum-thickness portion.
Although indoor heat transfer pipe 12 and outdoor heat transfer pipe 22 are flat pipes, and indoor pipes 13 and 14, connecting pipes 6 and 7, and outdoor pipes 23 to 28 are circular pipes in air conditioner 100 in accordance with the specific example described above, these sectional shapes may each be any shape.
Connecting pipes 6 and 7 may have a relatively thick portion and a relatively thin portion in the circumferential direction. In this case, the thin portion in the circumferential direction of connecting pipes 6 and 7 is the thinner portion which is thinner than the minimum-thickness portion of first refrigerant pipe 3. Further, connecting pipes 6 and 7 may have a relatively thick portion and a relatively thin portion in the axial direction. For example, a portion of each of connecting pipes 6 and 7 (a portion closer to one end or the other end of each of connecting pipes 6 and 7) closer to either one of flare portions 8a, 8b, 9a, and 9b may have a thickness relatively thinner than that of the other portion of each of connecting pipes 6 and 7. In this case, the portion of each of connecting pipes 6 and 7 is the thinner portion which is thinner than the minimum-thickness portion of first refrigerant pipe 3. Further, only either one of connecting pipes 6 and 7 may be provided as the thinner portion described above.
In air conditioner 100 in accordance with the specific example described above, first refrigerant pipe 3 and second refrigerant pipe 4 may each have any configuration as long as thickness uo1 of the thinner portion of second refrigerant pipe 4 (see
Further, thickness ti1 of base material 31 of the minimum-thickness portion of first refrigerant pipe 3 may be thinner than thickness to1 of base material 41 of the thinner portion of second refrigerant pipe 4. In this case, thickness si1 of anticorrosion layer 32 of the minimum-thickness portion of first refrigerant pipe 3 (see
Further, thickness ti1 of base material 31 of the minimum-thickness portion of first refrigerant pipe 3 may be thicker than thickness to1 of base material 41 of the thinner portion of second refrigerant pipe 4. In this case, thickness si1 of anticorrosion layer 32 of the minimum-thickness portion of first refrigerant pipe 3 (see
Preferably, thickness si1 of anticorrosion layer 32 (the first anticorrosion portion) of the minimum-thickness portion of first refrigerant pipe 3 (see
Next, an air conditioner in accordance with a second embodiment will be described. The air conditioner in accordance with the second embodiment has basically the same configuration as that of air conditioner 100 in accordance with the first embodiment, and differs from the latter in that the former has a limitation that each ratio (si1/ti1, si2/ti2) of thickness si1, si2 of anticorrosion layer 32, 34 (see
Since the above ratio (si1/ti1, si2/ti2) for first refrigerant pipe 3 is more than or equal to 3%, first refrigerant pipe 3 can fully satisfy the strength required for an ordinary air conditioner. Accordingly, the air conditioner in accordance with the second embodiment suppresses refrigerant leakage in a room, and has a high safety even when using a flammable refrigerant.
On the other hand, bonding of the pipes constituting first refrigerant pipe 3 or bonding between indoor heat transfer pipe 12 and indoor fin 15 is performed by brazing, for example. During heating for brazing, there occurs a phenomenon that a constituent of a brazing material diffuses into the base material. On this occasion, when the base material has a small thickness, so-called erosion, in which the substantial thickness of the base material decreases and leads to damage to the base material, is likely to occur. If the anticorrosion layer of the first refrigerant pipe has a too large thickness, it becomes necessary to limit the thickness of the base material of the first refrigerant pipe due to a constraint on external dimensions of the first refrigerant pipe, and occurrence of the above erosion is a concern.
In contrast, in the air conditioner in accordance with the second embodiment, since the above ratio (si1/ti1, si2/ti2) for first refrigerant pipe 3 is less than or equal to 50%, thickness ti1, ti2 of base material 31, 33 can be set to a thickness which can fully suppress occurrence of erosion. That is, in the air conditioner in accordance with the second embodiment, since the above ratio (si1/ti1, si2/ti2) for first refrigerant pipe 3 is more than or equal to 3% and less than or equal to 50%, first refrigerant pipe 3 has a sufficient strength, and occurrence of erosion in first refrigerant pipe 3 is fully suppressed. Accordingly, the air conditioner in accordance with the second embodiment suppresses refrigerant leakage in a room, and has a high safety even when using a flammable refrigerant.
Next, an air conditioner in accordance with a third embodiment will be described. The air conditioner in accordance with the third embodiment has basically the same configuration as that of air conditioner 100 in accordance with the first embodiment, and differs from the latter in that the former has a limitation that each ratio (ui1/D, ui2/D) of thickness ui1, ui2 (see
It can be seen from
Since the above ratio (ui1/D, ui2/D) for first refrigerant pipe 3 is more than or equal to 6%, first refrigerant pipe 3 can fully satisfy the strength required for an ordinary air conditioner, even at the minimum-thickness portion. That is, the air conditioner in accordance with the third embodiment, in which the above ratio is more than or equal to 6% and less than or equal to 38%, has a high cooling performance, and suppresses refrigerant leakage from first refrigerant pipe 3 placed in a room, and thus can safely use a flammable refrigerant as a heat medium.
Further, if the cross sectional area of the refrigerant flow path in the first refrigerant pipe is reduced, surface tension which acts on a fluid flowing in the first refrigerant pipe is increased, and a refrigerator oil flowing through the refrigerant flow path of the air conditioner together with the refrigerant is likely to stagnate in the first refrigerant pipe. As a result, in an air conditioner including such a first refrigerant pipe, abnormalities such as clogging of the flow path due to the refrigerator oil, failure of the compressor due to poor circulation of the refrigerator oil, and the like are likely to occur.
In contrast, in the air conditioner in accordance with the third embodiment, since the above ratio is less than or equal to 38%, a reduction in the cross sectional area of the refrigerant flow path in first refrigerant pipe 3 is suppressed, and occurrence of the above abnormalities due to stagnation of the refrigerator oil is suppressed.
It can be seen from
Next, an air conditioner in accordance with a fourth embodiment will be described. The air conditioner in accordance with the fourth embodiment has basically the same configuration as that of the air conditioner in accordance with the first embodiment, and differs from the latter in that a material constituting first refrigerant pipe 3 (see
A material constituting base materials 31 and 33 (see
Table 1 shows examples of metal materials which can be adopted as the materials constituting first refrigerant pipe 3 and second refrigerant pipe 4, and standard electrode potentials (25° C.) thereof. The materials constituting first refrigerant pipe 3 and second refrigerant pipe 4 are each at least one selected from the group consisting of, for example, silver (Ag), Cu, lead (Pb), iron (Fe), Cd, Zn, Al, and material 1050-O, material 1050-H18, material 1200-O, material 3003-O, and material 3004-O as aluminum alloys. For example, the material constituting base materials 31 and 33 of first refrigerant pipe 3 is Cu, and the material constituting base materials 41, 43, and 45 of second refrigerant pipe 4 is Al.
With such a configuration, corrosion is less likely to proceed in first refrigerant pipe 3 than in second refrigerant pipe 4, and thus the air conditioner in accordance with the fourth embodiment can prevent refrigerant leakage in a room more reliably than air conditioner 100.
On this occasion, anticorrosion layers 32 and 34 of first refrigerant pipe 3 and anticorrosion layers 42, 44, and 46 of second refrigerant pipe 4 may be constituted of the same material. Preferably, a material constituting anticorrosion layers 32 and 34 of first refrigerant pipe 3 has a standard electrode potential (25° C.) higher than that of a material constituting anticorrosion layers 42, 44, and 46 of second refrigerant pipe 4. In the latter case, the material constituting anticorrosion layers 32 and 34 of first refrigerant pipe 3 may be the same as the material constituting base materials 41, 43, and 45 of second refrigerant pipe 4. For example, the material constituting base materials 31 and 33 of first refrigerant pipe 3 may be Cu, the material constituting base materials 41, 43, and 45 of second refrigerant pipe 4 and the material constituting anticorrosion layers 32 and 34 of first refrigerant pipe 3 may be Al, and the material constituting anticorrosion layers 42, 44, and 46 of second refrigerant pipe 4 may be material 3003-O.
Further, base materials 31 and 33 of first refrigerant pipe 3 and base materials 41, 43, and 45 of second refrigerant pipe 4 may be constituted of the same material, and the material constituting anticorrosion layers 32 and 34 of first refrigerant pipe 3 may have a standard electrode potential (25° C.) higher than that of the material constituting anticorrosion layers 42, 44, and 46 of second refrigerant pipe 4. Also with such a configuration, corrosion is less likely to proceed in first refrigerant pipe 3 than in second refrigerant pipe 4, and thus the air conditioner in accordance with the fourth embodiment can prevent refrigerant leakage in a room more reliably than air conditioner 100.
Next, an air conditioner in accordance with a fifth embodiment will be described with reference to
Referring to
With such a configuration, indoor heat transfer pipe 12 is not heated to a high temperature and thus it does not become brittle, suppressing a reduction in strength and a reduction in resistance to corrosion due to embrittlement. Thereby, the air conditioner in accordance with the fifth embodiment can suppress refrigerant leakage in a room more reliably than air conditioner 100 in which indoor heat transfer pipe 12 is bonded to the plurality of indoor fins 15 by brazing.
Next, an air conditioner in accordance with a sixth embodiment will be described. The air conditioner in accordance with the sixth embodiment has basically the same configuration as that of air conditioner 100 in accordance with the first embodiment, and differs from the latter in that outdoor heat transfer pipe 22 (see
Thickness uo2 of outdoor heat transfer pipe 22 (see
In such an air conditioner, not only at the time of manufacturing but also at the time of use after a predetermined period has passed from the beginning of use, outdoor heat transfer pipe 22 serves as the thinner portion of second refrigerant pipe 4 (the minimum-thickness portion in the refrigerant pipes of the air conditioner). Also with such a configuration, the air conditioner in accordance with the sixth embodiment can suppress occurrence of refrigerant leakage in a room, and has a high safety even when using a flammable refrigerant.
Thickness uo2 of outdoor heat transfer pipe 22 (see
Preferably, in the air conditioner in accordance with the sixth embodiment, thickness si1 of anticorrosion layer 32 (the first anticorrosion portion) of the minimum-thickness portion of first refrigerant pipe 3 (see
Outdoor heat transfer pipe 22 may have a relatively thick portion and a relatively thin portion in the circumferential direction. In this case, the thin portion in the circumferential direction of outdoor heat transfer pipe 22 is the thinner portion which is thinner than the minimum-thickness portion of first refrigerant pipe 3. Further, outdoor heat transfer pipe 22 may have a relatively thick portion and a relatively thin portion in the axial direction. In this case, the portion of outdoor heat transfer pipe 22 is the thinner portion which is thinner than the minimum-thickness portion of first refrigerant pipe 3.
The thickness of a maximum-thickness portion of second refrigerant pipe 4 (at least one of connecting pipes 6 and 7 and outdoor pipes 23 to 28) is less than or equal to thickness ui1 of the minimum-thickness portion of first refrigerant pipe 3 (see
Next, an air conditioner in accordance with a seventh embodiment will be described. The air conditioner in accordance with the seventh embodiment has basically the same configuration as that of air conditioner 100 in accordance with the first embodiment, and differs from the latter in that entire second refrigerant pipe 4 is provided as a minimum-thickness portion of second refrigerant pipe 4. In other words, in the air conditioner in accordance with the seventh embodiment, second refrigerant pipe 4 (see
In such an air conditioner, entire second refrigerant pipe 4 serves as a portion thinner than the minimum-thickness portion of first refrigerant pipe 3 (a minimum-thickness portion in the refrigerant pipes of the air conditioner). Also with such a configuration, the air conditioner in accordance with the seventh embodiment can suppress occurrence of refrigerant leakage in a room, and has a high safety even when using a flammable refrigerant. The thickness of entire second refrigerant pipe 4 at the time of manufacturing is thicker than the corrosion amount (the amount of reduction in thickness) of second refrigerant pipe 4 estimated in the design standard use period, for example. In this case, the air conditioner in accordance with the seventh embodiment can suppress occurrence of refrigerant leakage in a room in the design standard use period, and has a high safety even when using a flammable refrigerant.
Next, an air conditioner in accordance with an eighth embodiment will be described. The air conditioner in accordance with the eighth embodiment has basically the same configuration as that of the air conditioner in accordance with the first embodiment, and differs from the latter in that the former has a limitation that the flammable refrigerant used as a heat medium includes a refrigerant including at least one of propylene-based carbon fluoride and ethylene-based carbon fluoride, which have a slight flammability and a low global warming potential (GWP).
The refrigerant including propylene-based carbon fluoride is R1234yf, R1234ze, or the like, for example. The refrigerant including ethylene-based carbon fluoride is R1123, R1132, or the like, for example.
Since the air conditioner in accordance with the eighth embodiment has the same configuration as air conditioner 100 in accordance with the first embodiment, the former can prevent leakage of the above flammable refrigerant in a room. Further, the refrigerant including at least one of propylene-based carbon fluoride and ethylene-based carbon fluoride as described above has a GWP of less than 150. Accordingly, the air conditioner in accordance with the eighth embodiment has less impact on global warming, and can satisfy the regulatory value (a GWP of less than 150) under the European F gas regulation.
Next, an air conditioner 101 in accordance with a ninth embodiment will be described. Air conditioner 101 in accordance with the ninth embodiment has basically the same configuration as that of air conditioner 100 in accordance with the first embodiment, and differs from the latter in that outdoor apparatus 2 further includes a detection unit 10 which is placed close to the portion smaller in thickness (thinner portion) of second refrigerant pipe 4, and can detect leakage of a flammable refrigerant.
Detection unit 10 may have any configuration as long as it can detect leakage of the flammable refrigerant. When the thinner portion is provided on connecting pipe 6 in second refrigerant pipe 4, detection unit 10 is placed close to connecting pipe 6.
When refrigerant leakage in second refrigerant pipe 4 is detected by detection unit 10, operation of air conditioner 101 is stopped by shutting off shut-off valves 54 and 55, for example. With such a configuration, air conditioner 101 can early detect refrigerant leakage in second refrigerant pipe 4 using detection unit 10, and thus can reduce the amount of leakage of the flammable refrigerant.
Outdoor unit 5 may further include an outdoor fan 58 which can blow air to outdoor heat exchanger 21. When refrigerant leakage in second refrigerant pipe 4 is detected by detection unit 10, operation of air conditioner 101 is stopped by shutting off shut-off valves 54 and 55, for example, and operation of outdoor fan 58 is continued. With such a configuration, air conditioner 101 can reduce the amount of leakage of the flammable refrigerant, and can diffuse the leaking flammable refrigerant using air flow generated by outdoor fan 58.
Outdoor apparatus 2 may further include a control unit 57 which is connected to detection unit 10 and shut-off valves 54 and 55, and is provided to be able to shut off shut-off valves 54 and 55 when refrigerant leakage is detected by detection unit 10.
When the thinner portion of second refrigerant pipe 4 has a relatively thick portion and a relatively thin portion, in other words, when a portion of the thinner portion is a minimum-thickness portion of second refrigerant pipe 4, detection unit 10 is preferably placed close to the minimum-thickness portion. When the thinner portion and minimum-thickness portion of second refrigerant pipe 4 is provided on outdoor heat transfer pipe 22 as in the air conditioner in accordance with the sixth embodiment, detection unit 10 is preferably placed close to outdoor heat transfer pipe 22. When entire second refrigerant pipe 4 is provided as the thinner portion and minimum-thickness portion as in the air conditioner in accordance with the seventh embodiment, detection unit 10 only needs to be placed close to any portion of second refrigerant pipe 4.
The thinner portion and minimum-thickness portion of second refrigerant pipe 4 may be provided in outdoor pipes 23 to 28. In this case, detection unit 10 only needs to be placed close to the minimum-thickness portion of outdoor pipes 23 to 28. Further, the thinner portion and minimum-thickness portion of second refrigerant pipe 4 may be provided at a plurality of places in connecting pipes 6 and 7, outdoor heat transfer pipe 22, and outdoor pipes 23 to 28. In this case, detection unit 10 is placed close to each minimum-thickness portion, one by one, for example.
Although the embodiments of the present invention have been described above, it is originally intended to combine features of the embodiments described above as appropriate.
Although the embodiments of the present invention have been described above, it is also possible to modify the embodiments described above in various manners. Further, the scope of the present invention is not limited to the embodiments described above. The scope of the present invention is defined by the scope of the claims, and is intended to include any modifications within the scope and meaning equivalent to the scope of the claims.
The present invention is particularly advantageously applicable to an air conditioner which uses a flammable refrigerant as a heat medium.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/081827 | 11/12/2015 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2017/081786 | 5/18/2017 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20150233622 | Yajima et al. | Aug 2015 | A1 |
| Number | Date | Country |
|---|---|---|
| 1182187 | May 1998 | CN |
| 2530915 | Apr 2016 | GB |
| 2001-099530 | Apr 2001 | JP |
| 2001-165468 | Jun 2001 | JP |
| 2001-165474 | Jun 2001 | JP |
| 2002-130848 | May 2002 | JP |
| 3454647 | Oct 2003 | JP |
| 2005-298913 | Oct 2005 | JP |
| 2012-211735 | Nov 2012 | JP |
| 2013-178073 | Sep 2013 | JP |
| 2014-020704 | Feb 2014 | JP |
| 2014-159952 | Sep 2014 | JP |
| 2012043492 | Apr 2012 | WO |
| 2014203353 | Dec 2014 | WO |
| Entry |
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| Extended EP Search Report dated Jan. 16, 2019 issued in corresponding EP patent application No. 15908306.2. |
| Office action dated Mar. 12, 2019 issued in corresponding JP patent application No. 2017-549931 (and English translation thereof). |
| International Search Report of the International Searching Authority dated Feb. 2, 2016 for the corresponding international application No. PCT/JP2015/081827 (and English translation). |
| Office Action dated Nov. 1, 2019 issued in corresponding CN patent application No. 201580084347.1 (and English translation). |
| Office Action dated Jan. 29, 2020 issued in corresponding JP patent application No. 2017-549931 (and English translation). |
| Number | Date | Country | |
|---|---|---|---|
| 20190024923 A1 | Jan 2019 | US |
