Technical Field
[0001] The present disclosure relates to a heat exchanger and a refrigeration cycle apparatus
including the same.
Background Art
[0002] There has been known a technique for improving the heat transfer performance of a
fin-and-tube heat exchanger by providing projections on a fin surface to control the
direction of flow of air.
[0003] For example, in a heat exchanger described in Patent Literature 1, projections for
preventing airflow separation are provided around each heat transfer tube to narrow
a dead water region in a wake flow portion of the heat transfer tube to bring about
improvement in heat transfer performance. The term "dead water region" here means
a region into which air does not flow and where there is a decrease in heat transfer
coefficient. In Patent Literature 1, a collision of an airflow with the projections
around the heat transfer tube causes air to flow into the wake flow portion of the
heat transfer tube, thus narrowing the dead water region in the wake flow portion
of the heat transfer tube.
Citation List
Patent Literature
Summary of Invention
Technical Problem
[0005] In Patent Literature 1, the projections are provided at positions at an angle of
±70 degrees to ±80 degrees to a stagnation point directed toward the center of the
heat transfer tube, with the result that the projections are sparsely provided around
the heat transfer tube. For this reason, in Patent Literature 1, it is hard to secure,
around the heat transfer tube, a region in which to provide additional projections
for improving the strength of each fin. The incapability of providing additional projections
for improving the strength of the fins causes the fin to bend in a longitudinal direction
when worked on. Further, the projections of Patent Literature 1 per se cannot bring
about sufficient improvement in heat transfer coefficient, as the surface area of
the fin is small in enlargement factor.
[0006] The present disclosure was made to solve such problems and has as an object to provide
a heat exchanger with improvement in longitudinal strength of each fin and improvement
in heat transfer coefficient and a refrigeration cycle apparatus including the same.
Solution to Problem
[0007] A heat exchanger according to an embodiment of the present disclosure includes a
plurality of fins spaced apart from one another in a first direction and a plurality
of heat transfer tubes penetrating through the plurality of fins, the plurality of
heat transfer tubes being spaced apart from one another in a second direction crossing
the first direction. Each of the plurality of fins includes a fin base surface that
is flat and a plurality of fin projections. The plurality of fin projections include
inner fin projections provided to separately surround each of the plurality of heat
transfer tubes, the inner fin projections protruding in the first direction from the
fin base surface, and outer fin projections provided to separately surround each of
the inner fin projections, the outer fin projections protruding in the first direction
from the fin base surface.
[0008] A refrigeration cycle apparatus according to an embodiment of the present disclosure
includes the heat exchanger as a condenser or an evaporator. Advantageous Effects
of Invention
[0009] In a heat exchanger according to an embodiment of the present disclosure, the inner
fin projections and the outer fin projections are provided around the heat transfer
tubes. The inner fin projections and the outer fin projections extend in a longitudinal
direction of the fin to surround the heat transfer tubes, thus bringing about improvement
in longitudinal strength of the fin. This makes it possible to cause the fin to bend
less in the longitudinal direction when worked on. Further, the inner fin projections
and the outer fin projections, which are provided around the heat transfer tubes,
enlarge the surface area of the fin base surface, thus bringing about improvement
in heat transfer coefficient on the surface of the fin 12. This makes it possible
to improve the heat transfer performance of the heat exchanger.
Brief Description of Drawings
[0010]
[Fig. 1] Fig. 1 is a perspective view showing a configuration of a heat exchanger
100 according to Embodiment 1.
[Fig. 2] Fig. 2 is a partial sectional side view showing only a basic configuration
of the heat exchanger 100 of Fig. 1.
[Fig. 3] Fig. 3 is a refrigerant circuit diagram showing an example of a configuration
of a refrigeration cycle apparatus 1 according to Embodiment 1.
[Fig. 4] Fig. 4 is a partial sectional side view showing a fin 12 of the heat exchanger
100 according to Embodiment 1.
[Fig. 5] Fig. 5 is a cross-sectional view taken along line A-A in Fig. 4.
[Fig. 6] Fig. 6 is a cross-sectional view taken along line B-B in Fig. 4.
[Fig. 7] Fig. 7 is a cross-sectional view showing Modification 1 of a fin 12 of the
heat exchanger 100 according to Embodiment 1.
[Fig. 8] Fig. 8 is a partial sectional side view showing Modification 2 of a fin 12
of the heat exchanger 100 according to Embodiment 1.
[Fig. 9] Fig. 9 is a partial sectional side view showing Modification 3 of a fin 12
of the heat exchanger 100 according to Embodiment 1.
[Fig. 10] Fig. 10 is a partial sectional side view showing Modification 4 of a fin
12 of the heat exchanger 100 according to Embodiment 1.
[Fig. 11] Fig. 11 is a partial sectional side view showing Modification 5 of a fin
12 of the heat exchanger 100 according to Embodiment 1.
[Fig. 12] Fig. 12 is a partial sectional side view showing Modification 6 of a fin
12 of the heat exchanger 100 according to Embodiment 1.
[Fig. 13] Fig. 13 is a partial sectional side view showing Modification 7 of a fin
12 of the heat exchanger 100 according to Embodiment 1.
[Fig. 14] Fig. 14 is a cross-sectional view taken along line A-A in Fig. 13.
[Fig. 15] Fig. 15 is a partial sectional side view showing a fin 12 of the heat exchanger
100 according to Embodiment 2.
[Fig. 16] Fig. 16 is a cross-sectional view taken along line A-A in Fig. 15.
[Fig. 17] Fig. 17 is a cross-sectional view taken along line C-C in Fig. 15.
[Fig. 18] Fig. 18 is a cross-sectional view showing Modification 1 of a fin 12 of
the heat exchanger 100 according to Embodiment 2.
[Fig. 19] Fig. 19 is a partial sectional side view showing Modification 2 of a fin
12 of the heat exchanger 100 according to Embodiment 2.
[Fig. 20] Fig. 20 is a cross-sectional view taken along line A-A in Fig. 19.
[Fig. 21] Fig. 21 is a partial sectional side view showing Modification 3 of a fin
12 of the heat exchanger 100 according to Embodiment 2.
[Fig. 22] Fig. 22 is a cross-sectional view taken along line A-A in Fig. 21.
[Fig. 23] Fig. 23 is a partial sectional side view showing Modification 4 of a fin
12 of the heat exchanger 100 according to Embodiment 2.
[Fig. 24] Fig. 24 is a cross-sectional view taken along line A-A in Fig. 23.
[Fig. 25] Fig. 25 is a partial sectional side view showing Modification 5 of a fin
12 of the heat exchanger 100 according to Embodiment 2.
[Fig. 26] Fig. 26 is a cross-sectional view taken along line C-C in Fig. 25.
[Fig. 27] Fig. 27 is a partial sectional side view showing Modification 6 of a fin
12 of the heat exchanger 100 according to Embodiment 2.
[Fig. 28] Fig. 28 is a cross-sectional view taken along line C-C in Fig. 27.
[Fig. 29] Fig. 29 is a partial sectional side view showing Modification 7 of a fin
12 of the heat exchanger 100 according to Embodiment 2.
[Fig. 30] Fig. 30 is a cross-sectional view taken along line C-C in Fig. 29.
[Fig. 31] Fig. 31 is a partial sectional side view showing Modification 8 of a fin
12 of the heat exchanger 100 according to Embodiment 2.
[Fig. 32] Fig. 32 is a cross-sectional view taken along line C-C in Fig. 31. Description
of Embodiments
[0011] The following describes, with reference to the drawings, a heat exchanger according
to an embodiment of the present disclosure and a refrigeration cycle apparatus including
the same. The present disclosure is not limited to the following embodiments but may
be modified variously without departing from the scope of the present disclosure.
The present disclosure encompasses all combinations of combinable ones of components
that are described in the following embodiments. Further, constituent elements given
identical reference signs in the drawings are identical or equivalent to each other,
and these signs are adhered to throughout the full text of the description. A dimensional
relationship of each constituent element relative to another, the shape of each constituent
element, or other features in the drawings may be different from actual ones.
Embodiment 1.
[0012] The following describes, with reference to the drawings, a heat exchanger 100 according
to Embodiment 1 and a refrigeration cycle apparatus 1 including the same.
[Basic Configuration of Heat Exchanger 100]
[0013] Fig. 1 is a perspective view showing a configuration of a heat exchanger 100 according
to Embodiment 1. The heat exchanger 100 is a fin-and-tube heat exchanger. As shown
in Fig. 1, the heat exchanger 100 includes a plurality of heat transfer tubes 11 and
a plurality of fins 12. The following description uses each of the nouns "heat transfer
tube 11" and "fin 12" in either the singular form or the plural form.
[0014] As shown in Fig. 1, each of the fins 12 is a rectangular flat-plate element. Those
fins 12 are placed at regular spacings from one another in a Y direction to form a
space through which air flows. In the following, the spacings are called "fin pitches".
The fin pitches do not need to be equal to one another but may be different from one
another. The fin pitches are each a center-to-center distance between adjacent ones
of the fins 12 in a thickness direction. Air flows along principal surfaces of the
fins 12 as indicated by an arrow R1 in Fig. 1. The fins 12 are constituted, for example,
by aluminum but are not limited to particular materials. It should be noted that the
direction in which air flows as indicated by the arrow R1 is called "X direction (third
direction)". Further, a longitudinal direction of the fins 12 is called "Z direction
(second direction)". Furthermore, the direction in which the fins 12 are stacked is
called "Y direction (first direction)". The X direction and the Z direction are orthogonal
to each other. Further, the X direction and the Y direction are orthogonal to each
other. Furthermore, the Y direction and the Z direction are orthogonal to each other.
It should be noted that a transverse direction of the fins 12 is sometimes referred
to as "X direction (third direction)". The Z direction is for example a vertical direction.
Assuming that the X direction is a column-wise direction in which columns of heat
transfer tubes 11 are arranged and that the Z direction is a row-wise direction in
which the heat transfer tubes 11 are arranged in rows, the heat transfer tubes 11
are arranged in one column and twelve rows in the example shown in Fig. 1. It should
be noted that the column count and row count of heat transfer tubes 11 are not limited
to these counts. For example, the heat transfer tubes 11 may be arranged in two or
more columns through the fins 12. It should be noted that Fig. 1 shows a case in which
a longitudinal direction of the heat transfer tubes 11 extends in the Y direction.
The Y direction is for example a horizontal direction. However, this case is not intended
to impose any limitation. That is, the longitudinal direction of the heat transfer
tubes 11 may extend in a vertical direction. In that case, the longitudinal direction
of the fins 12 is a horizontal direction.
[0015] As shown in Fig. 1, the plurality of heat transfer tubes 11 are disposed to penetrate
through the fins 12. Accordingly, the longitudinal direction of the heat transfer
tubes 11 is the Y direction. Further, those heat transfer tubes 11 are placed parallel
to one another at regular spacings from one another in the Z direction. In the following,
the spacings are called "tube pitches". The tube pitches do not need to be equal to
one another but may be different from one another. The tube pitches are each a center-to-center
distance between adjacent ones of the heat transfer tubes 11 in the Z direction. As
indicated by arrows R2 in Fig. 1, refrigerant flows through the heat transfer tubes
11. Ones of the heat transfer tubes 11 that are adjacent to each other in the Z direction
have their ends connected to each other by a U-tube 11a as shown in Fig. 1. This causes
the plurality of heat transfer tubes 11 to be combined to make a single tube so that
the refrigerant sequentially flows. Alternatively, the heat transfer tubes 11 do not
need to be combined to make a single tube. The heat transfer tubes 11 are constituted
a highly thermal conductive metal such as copper or a copper alloy but are not limited
to particular materials.
[0016] Fig. 2 is a partial sectional side view showing only a basic configuration of the
heat exchanger 100 of Fig. 1. Fig. 2 shows a cross-section taken at one place in the
Y direction. Specifically, Fig. 2 shows the principal surface of a fin 12 and cross-sections
of heat transfer tubes 11. Each of the heat transfer tubes 11 is constituted, for
example, by a circular tube or a flat tube. Figs. 1 and 2 show a case in which the
heat transfer tubes 11 are circular tubes.
[0017] The heat exchanger 100 exchanges heat between air flowing along the principal surfaces
of the fins 12 and refrigerant flowing through the heat transfer tubes 11. The heat
exchanger 100 is placed so that air flows in the X direction.
[Basic Configuration of Refrigeration Cycle Apparatus 1]
[0018] The heat exchanger 100 shown in Fig. 1 is used, for example, in a refrigeration cycle
apparatus 1. Fig. 3 is a refrigerant circuit diagram showing an example of a configuration
of the refrigeration cycle apparatus 1 according to Embodiment 1. As shown in Fig.
3, the refrigeration cycle apparatus 1 includes a heat source side unit 2 and a load
side unit 3.
[0019] As shown in Fig. 3, the heat source side unit 2 and the load side unit 3 are connected
to each other by a refrigerant pipe 8. The heat exchanger 100 can be used in both
the heat source side unit 2 and the load side unit 3. In the following, a heat exchanger
100 disposed in the heat source side unit 2 is called "heat exchanger 100A", and a
heat exchanger 100 disposed in the load side unit 3 is called "heat exchanger 100B".
[0020] As shown in Fig. 3, the load side unit 3 includes the heat exchanger 100B, an air-sending
device 7B, a controller 9B, and a portion of the refrigerant pipe 8. The air-sending
device 7B sends air to the heat exchanger 100B. The heat exchanger 100B exchanges
heat between refrigerant flowing through the heat transfer tubes 11 and air. In a
case in which the refrigeration cycle apparatus 1 performs heating on the side of
the load side unit 3, the heat exchanger 100B functions as a condenser, and in a case
in which the refrigeration cycle apparatus 1 performs cooling on the side of the load
side unit 3, the heat exchanger 100B functions as an evaporator.
[0021] The air-sending device 7B is for example a propeller fan. The air-sending device
7B is constituted by a fan motor 7a and a fan 7b. The fan 7b rotates with the fan
motor 7a serving as a power source. The rotation speed of the air-sending device 7B
is controlled by the controller 9B.
[0022] Further, as shown in Fig. 3, the heat source side unit 2 includes the heat exchanger
100A, a controller 9A, a compressor 4, a flow switching device 5, an expansion valve
6, an air-sending device 7A, and a portion of the refrigerant pipe 8. The heat source
side unit 2 may further include other components such an accumulator.
[0023] The heat exchanger 100A exchanges heat between refrigerant flowing through the heat
transfer tubes 11 and air. In a case in which the refrigeration cycle apparatus 1
performs heating on the side of the load side unit 3, the heat exchanger 100A functions
as an evaporator, and in a case in which the refrigeration cycle apparatus 1 performs
cooling on the side of the load side unit 3, the heat exchanger 100A functions as
a condenser.
[0024] The air-sending device 7A sends air to the heat exchanger 100A. The air-sending device
7A is for example a propeller fan. As with the air-sending device 7B, the air-sending
device 7A is constituted by a fan motor 7a and a fan 7b. The rotation speed of the
air-sending device 7A is controlled by the controller 9A.
[0025] The compressor 4 suctions low-pressure gas refrigerant, compresses the low-pressure
gas refrigerant into high-pressure gas refrigerant, and discharges the high-pressure
gas refrigerant. The compressor 4 is for example an inverter compressor. The inverter
compressor is enabled by the control of an inverter circuit or other circuits to change
the amount of refrigerant that is sent out per unit time. The inverter circuit is
mounted, for example, in the controller 9A.
[0026] The flow switching device 5 is a valve configured to switch among directions in
which refrigerant in the refrigerant pipe 8 flows. The flow switching device 5 is
constituted, for example, by a four-way valve. The flow switching device 5 is switched
by the control of the controller 9A between a case in which the refrigeration cycle
apparatus 1 performs a cooling operation and a case in which the refrigeration cycle
apparatus 1 performs a heating operation. When the refrigeration cycle apparatus 1
performs cooling on the side of the load side unit 3, the flow switching device 5
is brought into a state indicated by solid lines in Fig. 3. As a result of that, the
refrigerant discharged from the compressor 4 flows into the heat exchanger 100A disposed
in the heat source side unit 2. On the other hand, when the refrigeration cycle apparatus
1 performs heating on the side of the load side unit 3, the flow switching device
5 is brought into a state indicated by dashed lines in Fig. 3. As a result of that,
the refrigerant discharged from the compressor 4 flows into the heat exchanger 100B
disposed in the load side unit 3.
[0027] The expansion valve 6 causes liquid refrigerant flowing thereinto to be decompressed
by expanding action and flow out so that refrigerant liquefied in a condenser can
be easily evaporated in an evaporator. Further, the expansion valve 6 adjusts the
amount of refrigerant to keep the amount of refrigerant appropriate for the load on
the evaporator. The expansion valve 6 is constituted, for example, by an electronic
expansion valve. The opening degree of the expansion valve 6 is controlled by the
controller 9A. As shown in Fig. 3, the expansion valve 6 is connected by the refrigerant
pipe 8 between the heat exchanger 100A and the heat exchanger 100B.
[0028] The refrigerant pipe 8 constitutes a refrigerant circuit by connecting the compressor
4, the flow switching device 5, the heat exchanger 100A, the expansion valve 6, and
the heat exchanger 100B to one another as shown in Fig. 3. The refrigerant pipe 8
is coupled to the heat transfer tubes 11 of the heat exchanger 100A and the heat transfer
tubes 11 of the heat exchanger 100B.
[Configuration of Fin 12]
[0029] Fig. 4 is a partial sectional side view showing a fin 12 of the heat exchanger 100
according to Embodiment 1. Fig. 4 shows the principal surface of the fin 12. Further,
Fig. 4 shows cross-sections of heat transfer tubes 11 parallel to the principal surface
of the fin 12. The heat transfer tubes 11 shown in Fig. 4 are circular tubes and are
circular in cross-section. As shown in Fig. 4, the heat transfer tubes 11 are arranged
in a line along the Z direction. The fin 12 has a leading edge 12a and a trailing
edge 12b. Since air flows in the direction of an arrow R1 of Fig. 4, the leading edge
12a is disposed further windward than the trailing edge 12b. The heat transfer tubes
11 are inserted in through holes 12c formed in the fin 12. The outside diameter of
each of the heat transfer tubes 11 is equal to the inside diameter of each of the
through holes 12c. Accordingly, the heat transfer tubes 11 are in close contact with
inner walls of the through holes 12c.
[0030] The principal surface of the fin 12 constitutes a fin base surface 121 that is flat.
The fin base surface 121 is provided with fin projections 122. The fin projections
122 protrude in the Y direction from the fin base surface 121, which is the principal
surface of the fin 12. The fin projections 122 include inner fin projections 122A
provided to separately surround each of the plurality of heat transfer tubes 11. Further,
the fin projections 122 include outer fin projections 122B provided to separately
surround each of the inner fin projections 122A. In the following description, the
inner fin projections 122A and the outer fin projections 122B are referred to simply
as "fin projections 122" in a case in which there is no particular need to distinguish
between them. The following description uses each of the nouns "fin projection 122",
"inner fin projection 122A ", and "outer fin projection 122B" in either the singular
form or the plural form.
[0031] It should be noted that although Fig. 4 uses hatching to indicate the fin projections
122 to distinguish them from the fin base surface 121, the fin projections 122 shown
in Fig. 4 are not cross-sections. Fig. 4 uses solid lines to indicate visible outlines
and edge lines of the fin projections 122 in a view of the fin base surface 121 in
the Y direction and uses hatching to indicate portions interposed between the visible
outlines and the edge lines. This applies to Figs. 8 to 13, Fig. 15, Fig. 19, Fig.
21, Fig. 23, Fig. 25, Fig. 27, Fig. 29, and Fig. 31.
[0032] As shown in Fig. 4, the fin projections 122 are circular in shape in a view of the
principal surface of the fin 12 in the Y direction. The heat transfer tubes 11, the
inner fin projections 122A, and the outer fin projections 122B are provided in a concentric
configuration. A relationship among the diameter of each of the heat transfer tubes
11, the diameter of each of the inner fin projections 122A, and the diameter of each
of the outer fin projections 122B is expressed as "Diameter of Heat Transfer Tube
11 < Diameter of Inner Fin Projection 122A < Diameter of Outer Fin Projection 122B".
[0033] The fin projections 122 are described with reference to Figs. 5 and 6. Fig. 5 is
a cross-sectional view taken along line A-A in Fig. 4. Fig. 6 is a cross-sectional
view taken along line B-B in Fig. 4. It should be noted that Figs. 5 and 6 omit to
illustrate the heat transfer tubes. As shown in Figs. 5 and 6, the through holes 12c
may have fin collars 12d at edges thereof. The fin collars 12d protrude in the Y direction
from the fin base surface 121, which is the principal surface of the fin 12, along
side surfaces of the heat transfer tubes 11 (see Fig. 4). Although, in Figs. 5 and
6, protruding distal ends of the fin collars 12d have bends, the protruding distal
ends do not need to have bends. Protruding portions of the fin collars 12d may be
linear in shape. It should be noted that although, in Figs. 5 and 6, the through holes
12c have the fin collars 12d, the through holes 12c do not need to have the fin collars
12d.
[0034] As shown in Figs. 5 and 6, there are gaps between the through holes 12c and the inner
fin projections 122A. In a case in which the heat transfer tubes 11, which are inserted
in the through holes 12c and protrude from the fin base surface 121, and the inner
fin projections 122A are provided in contact with each other, stress concentrates
on boundary portions of the heat transfer tubes 11 and the inner fin projections 122A
in the formation of the fin 12. The present embodiment avoids concentration of stress
in the formation of the fin 12 by providing gaps between the heat transfer tubes 11
and the inner fin projections 122A.
[0035] Further, the inner fin projections 122A and the outer fin projections 122B protrude
in the same direction from the fin base surface 121 in the Y direction. There are
gaps between the inner fin projections 122A and the outer fin projections 122B. These
gaps between the inner fin projections 122A and the outer fin projections 122B are
called "first flat portions 121A". In a case in which no first flat portions 121A
are provided between the inner fin projections 122A and the outer fin projections
122B, stress concentrates on boundary portions of the inner fin projections 122A and
the outer fin projections 122B in the formation of the fin. Concentration of stress
in the formation of the fin is avoided by providing the first flat portions 121A.
[0036] In Figs. 5 and 6, the inner fin projections 122A and the outer fin projections 122B
are triangular in cross-section. However, the inner fin projections 122A and the outer
fin projections 122B do not need to be triangular in cross-section. The inner fin
projections 122A and the outer fin projections 122B may for example be rectangular,
polygonal, or circular in cross-section.
[0037] Next, the height of each of the inner fin projections 122A and the height of each
of the outer fin projections 122B are described. Assume that h1 is the height of each
of the inner fin projections 122A from the fin base surface 121 and that h2 is the
height of each of the outer fin projections 122B from the fin base surface 121. Note
here that the height h1 of each of the inner fin projections 122A and the height h2
of each of the outer fin projections 122B may be equal to each other as shown in Figs.
5 and 6.
[0038] A heat exchanger 100 according to the present embodiment includes a plurality of
fins 12 spaced apart from one another in a first direction Y and a plurality of heat
transfer tubes 11 penetrating through the plurality of fins 12, the plurality of heat
transfer tubes 11 being spaced apart from one another in a second direction Z crossing
the first direction Y. Each of the plurality of fins 12 includes a fin base surface
121 that is flat and a plurality of fin projections 122. The plurality of fin projections
122 include inner fin projections 122A provided to separately surround each of the
plurality of heat transfer tubes 11, the inner fin projections 122A protruding in
the first direction Y from the fin base surface 121, and outer fin projections 122B
provided to separately surround each of the inner fin projections 122A, the outer
fin projections 122B protruding in the first direction Y from the fin base surface
121.
[0039] According to this configuration, the inner fin projections 122A and the outer fin
projections 122B are provided to surround the heat transfer tubes 11. For this reason,
the fin projections 122 have portions extending in the second direction Z of the fin
12. That is, the provision of fin projections 122 having portions along the longitudinal
direction of the fin 12 brings about improvement in longitudinal strength of the fin
12. This keeps the fin 12 from bending in the longitudinal direction when worked on,
for example when pressed or when stacked. This brings about improvement in producibility
of the heat exchanger.
[0040] Further, the provision of the inner fin projections 122A and the outer fin projections
122B around the heat transfer tubes 11 brings about a heat exchange promoting effect
that is similar to that which is brought about in a case in which projections are
provided in both the longitudinal direction and transverse direction of the fin 12.
That is, regardless of whether air flows in from the longitudinal direction or transverse
direction of the fin 12, the fin projections 122 are provided in the direction of
flow of air. This makes it possible to effectively utilize the inner fin projections
122A and the outer fin projections 122B as heat transfer elements. This results in
improvement in heat transfer coefficient on the surface of the fin 12, bringing about
improvement in heat transfer performance of the heat exchanger.
[0041] Further, in the fin 12 according to the present embodiment, the inner fin projections
122A and the outer fin projections 122B are provided around through holes 12c in which
the heat transfer tubes 11 are inserted. In the formation of the fin projections 122,
the material is stretched in a well-balanced manner from all parts of the fin 12,
so that distortions in shape due to concentration of stress on the fin base surface
121 can be reduced. This brings about improvement in workability of the fin 12, bringing
about improvement in manufacturability of the heat exchanger.
[0042] Further, in the heat exchanger 100 according to the present embodiment, the plurality
of heat transfer tubes 11 are circular in cross-section, and each of the inner fin
projections 122A and a corresponding one of the outer fin projections 122B are provided
concentrically with a corresponding one of the plurality of heat transfer tubes 11.
In this configuration, the inner fin projection 122A and the outer fin projection
122B are provided along a circumferential direction of a circular cross-section of
the heat transfer tube 11. In the formation of the inner fin projection 122A and the
outer fin projection 122B, the fin is deformed uniformly in the circumferential direction
of the cross-section of the heat transfer tube 11, so that it is hard for stress to
concentrate. This brings about improvement in formability of the fin 12, resulting
in improvement in manufacturability of the heat exchanger.
[0043] Further, in the heat exchanger 100 according to the present embodiment, the fin base
surface 121 has first flat portions 121A between the inner fin projections 122A and
the outer fin projections 122B. In this configuration, the first flat portions 121A
allows the inner fin projections 122A and the outer fin projections 122B to be provided
on the fin 12 without touching each other. This makes it hard for stress to concentrate
between the inner fin projections 122A and the outer fin projections 122B in the formation
of the fin. This brings about improvement in formability of the fin 12, resulting
in improvement in manufacturability of the heat exchanger.
[Modification 1 of Embodiment 1]
[0044] Fig. 7 is a cross-sectional view showing Modification 1 of a fin 12 of the heat exchanger
100 according to Embodiment 1. Fig. 7 shows a portion of Modification 1 that corresponds
to a cross-section taken along line B-B in Fig. 4. In Modification 1 shown in Fig.
7 too, as in the case of Embodiment 1, the fin projections 122 include inner fin projections
122A and outer fin projections 122B.
[0045] The heat exchanger 100 according to Modification 1 is different from Embodiment 1
in relationship between the height h1 of each of the inner fin projections 122A from
the fin base surface 121 and the height h2 of each of the outer fin projections 122B
from the fin base surface 121. In Embodiment 1 shown in Figs. 5 and 6, the height
h1 of each of the inner fin projections 122A and the height h2 of each of the outer
fin projections 122B are equal to each other. Meanwhile, in Modification 1, as shown
in Fig. 7, the height h1 of each of the inner fin projections 122A is greater than
the height h2 of each of the outer fin projections 122B. Other components and workings
are not described here, as they are the same as those of Embodiment 1.
[0046] In the heat exchanger 100 according to Embodiment 1 or Modification 1 of Embodiment
1, a relationship between the height h1 of each of the inner fin projections 122A
and the height h2 of each of the outer fin projections 122B is expressed as h2 ≤ h1.
A portion of air colliding with the outer fin projection 122B flows along a slope
of the outer fin projection 122B toward an apex of the outer fin projection 122B and
passes through the highest part of the outer fin projection 122B. If the height h2
of the outer fin projection 122B is higher than the height h1 of the inner fin projection
122A, air passing through the highest part of the outer fin projection 122B flows
into a space above the highest part of the inner fin projection 122A, that is, a space
in which the inner fin projection 122A is not present. Therefore, a portion of air
colliding with the outer fin projection 122B does not collide with the inner fin projection
122A. Meanwhile, in a case in which the height h2 of the outer fin projection 122B
and the height h1 of the inner fin projection 122A are equal to each other, it is
easy for air colliding with the outer fin projection 122B to collide with the inner
fin projection 122A. This allows more air to flow into the space between the outer
fin projection 122B and the inner fin projection 122A. Furthermore, in a case in which
the height h2 of the outer fin projection 122B is lower than the height h1 of the
inner fin projection 122A, air passing beyond the highest part of the outer fin projection
122B collides with the inner fin projection 122A. This allows more air to flow into
the space between the outer fin projection 122B and the inner fin projection 122A.
Further, air colliding with the inner fin projection 122A also easily flows into a
gap between the inner fin projection 122A and the heat transfer tube 11. Accordingly,
in the configuration of Embodiment 1 or Modification 1, in which the relationship
between the height h1 of the inner fin projection 122A and the height h2 of the outer
fin projection 122B is expressed as h2 ≤ h1, more air flows into the gap between the
outer fin projection 122B and the inner fin projection 122A and the gap between the
inner fin projection 122A and the heat transfer tube 11. This increases the area of
contact of air with the outer fin projection 122B and the inner fin projection 122A,
bringing about improvement in heat transfer coefficient on the surface of the fin
12 and improvement in heat transfer performance of the heat exchanger.
[Modification 2 of Embodiment 1]
[0047] Fig. 8 is a partial sectional side view showing Modification 2 of a fin 12 of the
heat exchanger 100 according to Embodiment 1. Fig. 8 shows the surface of the fin
12 and cross-sections of heat transfer tubes 11 parallel to the principal surface
of the fin 12. In Modification 2 shown in Fig. 8 too, as in the case of Embodiment
1, the fin projections 122 include inner fin projections 122A and outer fin projections
122B.
[0048] As shown in Fig. 8, the inner fin projections 122A and the outer fin projections
122B in Modification 2 of Embodiment 1 are provided in rectangular shapes to surround
the heat transfer tubes 11. Differences from Embodiment 1 lie in the shapes of the
inner fin projections 122A and the outer fin projections 122B. Other components and
workings are not described here, as they are the same as those of Embodiment 1.
[0049] In Modification 2, since the inner fin projections 122A and the outer fin projections
122B are rectangular, the fin projections 122 have portions linearly extending in
the Z direction of the fin 12. That is, the provision of fin projections 122 having
linear portions along the longitudinal direction of the fin 12 brings about further
improvement in longitudinal strength of the fin 12. As in the case of Embodiment 1,
this keeps the fin 12 from bending in the longitudinal direction when worked on, for
example when pressed or when stacked. This brings about improvement in producibility
of the heat exchanger.
[Modification 3 of Embodiment 1]
[0050] Fig. 9 is a partial sectional side view showing Modification 3 of a fin 12 of the
heat exchanger 100 according to Embodiment 1. Fig. 9 shows the surface of the fin
12 and cross-sections of heat transfer tubes 11 parallel to the principal surface
of the fin 12. In Modification 3 shown in Fig. 9 too, as in the case of Embodiment
1, the fin projections 122 include inner fin projections 122A and outer fin projections
122B.
[0051] As shown in Fig. 9, the inner fin projections 122A and the outer fin projections
122B in Modification 3 of Embodiment 1 are provided in elliptical shapes to surround
the heat transfer tubes 11. Differences from Embodiment 1 lie in the shapes of the
inner fin projections 122A and the outer fin projections 122B. Other components and
workings are not described here, as they are the same as those of Embodiment 1.
[0052] As shown in Fig. 9, the inner fin projections 122A and the outer fin projections
122B are larger in diameter in the X direction than in the Z direction. That is, the
fin projections 122 have portions elongated in the transverse direction of the fin
12, that is, the direction in which air flows in. This makes it easy for air to make
contact with the fin projections 122. As in the case of Embodiment 1, this results
in improvement in heat transfer coefficient on the surface of the fin 12.
[Modification 4 of Embodiment 1]
[0053] Fig. 10 is a cross-sectional view showing Modification 4 of a fin 12 of the heat
exchanger 100 according to Embodiment 1. Fig. 10 shows the surface of the fin 12 and
cross-sections of heat transfer tubes 11 parallel to the principal surface of the
fin 12. In Modification 4 shown in Fig. 10 too, as in the case of Embodiment 1, the
fin projections 122 include inner fin projections 122A and outer fin projections 122B.
[0054] As shown in Fig. 10, in Modification 4 of Embodiment 4, the inner fin projections
122A and the outer fin projections 122B are different in shape from each other. As
with the inner fin projections 122A in Embodiment 1, each of the inner fin projections
122A in Modification 4 is provided concentrically with a corresponding one of the
heat transfer tubes 11. Meanwhile, the outer fin projections 122B in Modification
4 are provided in elliptical shapes to surround the heat transfer tubes 11. Differences
from Embodiment 1 lie in the shapes of the outer fin projections 122B. Other components
and workings are not described here, as they are the same as those of Embodiment 1.
[0055] In Modification 4, the inner fin projections 122A are in the shapes of circles provided
concentrically with the heat transfer tubes 11. Meanwhile, the outer fin projections
122B are in the shapes of ellipses. As shown in Fig. 10, the outer fin projections
122B are larger in diameter in the X direction than in the Z direction. That is, the
outer fin projections 122B have portions elongated in the transverse direction of
the fin 12, that is, the direction in which air flows in. This makes it easy for air
to make contact with the fin projections 122. As in the case of Embodiment 1, this
results in improvement in heat transfer coefficient on the surface of the fin 12.
[Modification 5 of Embodiment 1]
[0056] Fig. 11 is a cross-sectional view showing Modification 5 of a fin 12 of the heat
exchanger 100 according to Embodiment 1. Fig. 11 shows the surface of the fin 12 and
cross-sections of heat transfer tubes 11 parallel to the principal surface of the
fin 12. In Modification 5 shown in Fig. 11 too, as in the case of Embodiment 1, the
fin projections 122 include inner fin projections 122A and outer fin projections 122B.
[0057] As shown in Fig. 11, in Modification 5 of Embodiment 1, additional fin projections
122D are provided to surround the outer fin projections 122B. Differences between
Embodiment 1 and Modification 5 lie in these additional fin projections 122D. Other
components and workings are not described here, as they are the same as those of Embodiment
1.
[0058] In Modification 5, one or more additional fin projections 122D are provided concentrically
with the heat transfer tubes 11 to surround the outer fin projections 122B. For this
reason, the fin projections 122 have portions elongated in the second direction Z
of the fin 12. That is, the provision of fin projections 122 having portions along
the longitudinal direction of the fin 12 brings about improvement in longitudinal
strength of the fin 12. This keeps the fin from bending in the longitudinal direction
when worked on, for example when pressed or when stacked. This brings about improvement
in producibility of the heat exchanger.
[0059] Further, the provision of the additional fin projections 122D around the outer fin
projections 122B brings about an effect that is similar to that which is brought about
in a case in which projections are added in both the longitudinal direction and transverse
direction of the fin 12. That is, regardless of whether air flows in from the longitudinal
direction or transverse direction of the fin 12, projections are added in the direction
of flow of air. This makes it possible to effectively utilize the additional fin projections
122D as heat transfer elements. Further, this makes it easier for inflow air to make
contact with the additional fin projections 122D, thus bringing about improvement
in heat transfer coefficient and improvement in heat transfer performance of the heat
exchanger.
[Modification 6 of Embodiment 1]
[0060] Fig. 12 is a partial sectional side view showing Modification 6 of a fin 12 of the
heat exchanger 100 according to Embodiment 1. Fig. 12 shows the surface of the fin
12 and cross-sections of heat transfer tubes 11 parallel to the principal surface
of the fin 12. In Modification 6 shown in Fig. 12 too, as in the case of Embodiment
1, the fin projections 122 include inner fin projections 122A and outer fin projections
122B.
[0061] As shown in Fig. 12, in Modification 6 of Embodiment 1, the heat transfer tubes 11
are constituted by flat tubes. Further, the inner fin projections 122A and the outer
fin projections 122B are provided in rectangular shapes to surround the heat transfer
tubes 11. Differences between Embodiment 1 and Modification 6 lie in the shapes of
the heat transfer tubes 11, the inner fin projections 122A, and the outer fin projections
122B. Other components and workings are not described here, as they are the same as
those of Embodiment 1.
[0062] In Modification 6, since the inner fin projections 122A and the outer fin projections
122B are rectangular, the fin projections 122 have portions linearly extending in
the Z direction of the fin 12. That is, the provision of fin projections 122 having
linear portions along the longitudinal direction of the fin 12 brings about further
improvement in longitudinal strength of the fin 12. As in the case of Embodiment 1,
this keeps the fin from bending in the longitudinal direction when worked on, for
example when pressed or when stacked. This brings about improvement in producibility
of the heat exchanger.
[Modification 7 of Embodiment 1]
[0063] Fig. 13 is a partial sectional side view showing Modification 7 of a fin 12 of the
heat exchanger 100 according to Embodiment 1. Fig. 13 shows the surface of the fin
12 and cross-sections of heat transfer tubes 11 parallel to the principal surface
of the fin 12. In Modification 7 shown in Fig. 13 too, as in the case of Embodiment
1, the fin projections 122 include inner fin projections 122A and outer fin projections
122B. Fig. 14 is a cross-sectional view taken along line A-A in Fig. 13.
[0064] As shown in Figs. 13 and 14, in Modification 7 of Embodiment 1, no first flat portions
121A are provided between the inner fin projections 122A and the outer fin projections
122B. This is a point of difference from Embodiment 1. Other components and workings
are not described here, as they are the same as those of Embodiment 1.
[0065] In Modification 7, the fin base surface 121 has no first flat portions 121A. This
makes it impossible to bring about an effect of avoiding concentration of stress between
the inner fin projections 122A and the outer fin projections 122B in the formation
of the fin. However, in terms of improvement in longitudinal strength of the fin 12
and improvement in heat transfer coefficient of the surface of the fin 12, Modification
7 brings about an effect that is similar to that of Embodiment 1.
[0066] In Embodiment 1 and Modifications 1 to 7 thereof, the shapes of the inner fin projections
122A and the outer fin projections 122B are described with reference to Fig. 4 and
Figs. 8 to 14. In each of Fig. 4 and Figs. 8 to 14, the plurality of heat transfer
tubes 11 are surrounded by inner fin projections 122A of the same shape. However,
inner fin projections 122A having different shapes may be provided separately for
each of the heat transfer tubes 11. Further, in each of Fig. 4 and Figs. 8 to 14,
the plurality of inner fin projections 122A are surrounded by outer fin projections
122B of the same shape. However, outer fin projections 122B having different shapes
may be provided separately for each of the heat transfer tubes 11.
Embodiment 2.
[0067] The following describes a heat exchanger 100 and a refrigeration cycle apparatus
1 according to Embodiment 2.
[Basic Configuration of Heat Exchanger 100]
[0068] A basic configuration of a heat exchanger 100 according to Embodiment 2 is not described
here, as it is the same as that of the heat exchanger 100 of Embodiment 1.
[Basic Configuration of Refrigeration Cycle Apparatus 1]
[0069] A basic configuration of a refrigeration cycle apparatus 1 according to Embodiment
2 is not described here, as it is the same as that of the refrigeration cycle apparatus
1 of Embodiment 1.
[Configuration of Fin 12]
[0070] Fig. 15 is a partial sectional side view showing a fin 12 of the heat exchanger 100
according to Embodiment 2. Fig. 15 shows the principal surface of the fin 12 and cross-sections
of heat transfer tubes 11. The cross-sections of the heat transfer tubes 11 shown
in Fig. 15 are cross-sections parallel to the principal surface of the fin 12. As
shown in Fig. 15, the heat transfer tubes 11 are arranged in a line along a column-wise
direction parallel with the longitudinal direction of the fin 12. The fin 12 has a
leading edge 12a and a trailing edge 12b. In the following, the upper heat transfer
tube 11 as seen from the front of the surface of paper of Fig. 15 is called "first
heat transfer tube 11A", and the lower heat transfer tube 11 as seen from the front
of the surface of paper of Fig. 15 is called "second heat transfer tube 11B".
[0071] As in the case of Embodiment 1, the principal surface of the fin 12 constitutes
a fin base surface 121 that is flat. Further, as in the case of Embodiment 1, the
inner fin projections 122A and the outer fin projections 122B are provided to protrude
in the Y direction from the fin base surface 121. In Embodiment 2, an inner fin projection
122A provided to surround the first heat transfer tube 11A is called "first inner
fin projection 122A-1". Further, an outer fin projection 122B provided to surround
the first inner fin projection 122A-1 is called "first outer fin projection 122B-1".
Furthermore, in Embodiment 2, an inner fin projection 122A provided to surround the
second heat transfer tube 11B is called "second inner fin projection 122A-2". Further,
an outer fin projection 122B provided to surround the second inner fin projection
122A-2 is called "second outer fin projection 122B-2".
[0072] The fin 12 in Embodiment 2 is described with reference to Figs. 15 to 17. Fig. 16
is a cross-sectional view taken along line A-A in Fig. 15. Fig. 17 is a cross-sectional
view taken along line C-C in Fig. 15. In the following description, the first inner
fin projection 122A-1 and the second inner fin projection 122A-2 are referred to simply
as "inner fin projections 122A" in a case in which there is no particular need to
distinguish between them. Further, the first outer fin projection 122B-1 and the second
outer fin projection 122B-2 are referred to simply as "outer fin projections 122B"
in a case in which there is no particular need to distinguish between them.
[0073] There is a gap between the first outer fin projection 122B-1 and the second outer
fin projection 122B-2. A portion of the gap between the first outer fin projection
122B-1 and the second outer fin projection 122B-2 surrounded by thick dot-and-dash
lines in Fig. 15 is called "second flat portion 121B". That is, when viewed from the
front of the surface of paper of Fig. 15, the second flat portion 121B is a portion
of the fin base surface 121 interposed between a lower semicircular portion of the
first outer fin projection 122B-1 and an upper semicircular portion of the second
outer fin projection 122B-2. Further, in Fig. 16, a linear portion between the first
outer fin projection 122B-1 and the second outer fin projection 122B-2 corresponds
to the second flat portion 121 B. In a case in which no second flat portion 121B is
provided between the first outer fin projection 122B-1 and the second outer fin projection
122B-2, stress concentrates on boundary portions of the first outer fin projection
122B-1 and the second outer fin projection 122B-2 in the formation of the fin. Concentration
of stress in the formation of the fin is avoided by providing the second flat portion
121B.
[0074] As shown in Fig. 15, the fin base surface 121 is provided with intermediate fin projections
122C. As shown in Fig. 17, the intermediate fin projections 122C protrude in the Y
direction from the portion of the fin base surface 121 situated between the first
outer fin projection 122B-1 and the second outer fin projection 122B-2. That is, in
Embodiment 2, the fin projections 122 include the inner fin projections 122A, the
outer fin projections 122B, and the intermediate fin projections 122C. As shown in
Figs. 16 and 17, the inner fin projections 122A, the outer fin projections 122B, and
the intermediate fin projections 122C protrude in the same direction from the fin
base surface 121 in the Y direction. A basic configuration of the fin 12 according
to Embodiment 2 is not described, as it is identical to that of Embodiment 1 except
for the intermediate fin projections 122C. It should be noted that the number of intermediate
fin projections 122C is not limited to 2, although two intermediate fin projections
122C are provided in Fig. 15. One intermediate fin projection 122C may be provided,
or three or more intermediate fin projections 122C may be provided.
[0075] The intermediate fin projections 122C are provided in a space between the first outer
fin projection 122B-1 and the second outer fin projection 122B-2 in the longitudinal
direction of the fin 12. However, the intermediate fin projections 122C do not need
to be wholly located in the space between the first outer fin projection 122B-1 and
the second outer fin projection 122B-2. As shown in Fig. 15, the intermediate fin
projections 122C need only be partially located in the space between the first outer
fin projection 122B-1 and the second outer fin projection 122B-2. In the present disclosure,
the space between the first outer fin projection 122B-1 and the second outer fin projection
122B-2 refers to the portion of the fin base surface 121 that corresponds to the second
flat portion 121B.
[0076] Further, in the present disclosure, a straight line passing through the center of
the first heat transfer tube 11A and the center of the second heat transfer tube 11B
along the Z direction is called "center line CL". In Fig. 15, a dot-and-dash line
indicating the A-A cross-section corresponds to the center line CL. The intermediate
fin projections 122C are provided at positions not crossing the center line CL.
[0077] Next, the shapes of the intermediate fin projections 122C are described with reference
to Fig. 15. Each of the intermediate fin projections 122C includes a first raised
portion 122c-1 and a second raised portion 122c-2 that rise from the fin base surface
121. The first raised portion 122c-1 and the second raised portion 122c-2 extend parallel
along the Z direction of the fin 12. The first raised portion 122c-1 is greater in
length than the second raised portion 122c-2. Further, in the X direction, the distance
between the first raised portion 122c-1 and the center line CL is longer than the
distance between the second raised portion 122c-2 and the center line CL.
[0078] The first raised portion 122c-1 has two ends in the Z direction. One of the two ends
of the first raised portion 122c-1 that is close to the first outer fin projection
122B-1 is called "first end 122c-1a". Further, one of the two ends of the first raised
portion 122c-1that is close to the second outer fin projection 122B-2 is called "second
end 122c-1b". That is, the first raised portion 122c-1 has the first end 122c-1a and
the second end 122c-1b. Further, the second raised portion 122c-2 has two ends in
the Z direction. One of the two ends of the second raised portion 122c-2 that is close
to the first outer fin projection 122B-1 is called "first end 122c-2a". Further, one
of the two ends of the second raised portion 122c-2 that is close to the second outer
fin projection 122B-2 is called "second end 122c-2b". That is, the second raised portion
122c-2 has the first end 122c-2a and the second end 122c-2b.
[0079] Next, a positional relationship between each of the intermediate fin projections
122C and the outer fin projections 122B is described with reference to a first virtual
line VL1 and a second virtual line VL2 that are indicated by dashed lines in Fig.
15. In the present disclosure, the first virtual line VL1 is a virtual straight line
passing through the first end 122c-1a of the first raised portion 122c-1 and the first
end 122c-2a of the second raised portion 122c-2. Further, the second virtual line
VL2 is herein a virtual straight line passing through the second end 122c-1b of the
first raised portion 122c-1 and the second end 122c-2b of the second raised portion
122c-2. As shown in Fig. 15, the first virtual line VL1 does not cross the first outer
fin projection 122B-1. Therefore, a given gap is formed between a portion of the intermediate
fin projection 122C connecting the first end 122c-1a of the first raised portion 122c-1
with the first end 122c-2a of the second raised portion 122c-2 and the first outer
fin projection 122B-1. Further, the second virtual line VL2 does not cross the second
outer fin projection 122B-2. Therefore, a given gap is formed between a portion of
the intermediate fin projection 122C connecting the second end 122c-1b of the first
raised portion 122c-1 with the second end 122-2b of the second raised portion 122c-2
and the second outer fin projection 122B-2. The given gaps here are portions of the
fin base surface 121 and flat regions having areas for avoiding concentration of stress
around the intermediate fin projection 122C in the formation of the fin. If the areas
of the gaps between the intermediate fin projection 122C and the outer fin projections
122B are small, concentration of stress around the intermediate fin projection 122C
in the formation of the fin cannot be avoided. The intermediate fin projection 122C
is provided so that the first virtual line VL1 does not cross the first outer fin
projection 122B-1. This makes it possible to secure a flat region on the fin base
surface 121 between the intermediate fin projection 122C and the first outer fin projection
122B-1 that can avoid concentration of stress in the formation of the fin. Further,
the intermediate fin projection 122C is provided so that the second virtual line VL2
does not cross the second outer fin projection 122B-2. This makes it possible to secure
a flat region on the fin base surface 121 between the intermediate fin projection
122C and the second outer fin projection 122B-2 that can avoid concentration of stress
in the formation of the fin.
[0080] In the heat exchanger 100 according to the present embodiment, the plurality of heat
transfer tubes 11 include a first heat transfer tube 11A and a second heat transfer
tube 11B that are adjacent to each other in the second direction Z. The inner fin
projections 122A include a first inner fin projection 122A-1 provided to surround
the first heat transfer tube 11A and a second inner fin projection 122A-2 provided
to surround the second heat transfer tube 11B. Further, the outer fin projections
122B include a first outer fin projection 122B-1 provided to surround the first inner
fin projection 122A-1 and a second outer fin projection 122B-2 provided to surround
the second inner fin projection 122A-2. Moreover, the fin base surface 121 has a second
flat portion 121B between the first outer fin projection 122B-1 and the second outer
fin projection 122B-2.
[0081] According to this configuration, the second flat portion 121B allows the first outer
fin projections 122B-1 and the second outer fin projection 122B-2 to be provided on
the fin 12 without touching each other. This prevents stress from concentrating between
the first outer fin projections 122B-1 and the second outer fin projection 122B-2
in the formation of the fin. This brings about improvement in formability of the fin
12, resulting in improvement in manufacturability of the heat exchanger.
[0082] Further, in the heat exchanger 100 according to the present embodiment, the plurality
of fin projections 122 include an intermediate fin projection 122C protruding in the
first direction Y from the fin base surface 121, and the intermediate fin projection
122C is provided so that at least part of the intermediate fin projection 122C is
located between the first outer fin projection 122B-1 and the second outer fin projection
122B-2 in the second direction Z.
[0083] According to this configuration, providing the intermediate fin projection 122C makes
it easy for air to make contact with the surface of the fin 12. This results in further
improvement in heat transfer coefficient on the surface of the fin 12. Further, locating
part of the intermediate fin projection 122C between the first outer fin projection
122B-1 and the second outer fin projection 122B-2 results in reducing a region in
which no fin projections 122 are present in the longitudinal direction of the fin
12. This brings about further improvement in longitudinal strength of the fin 12.
[0084] Further, in the heat exchanger 100 according to the present embodiment, the intermediate
fin projection 122C is provided at a position not crossing a center line CL passing
through a center of the first heat transfer tube 11A and a center of the second heat
transfer tube 11B along the second direction Z. Note here that in the second direction
Z of the fin 12, a length between the first outer fin projection 122B-1 and the second
outer fin projection 122B-2 is shortest in a portion through which the center line
CL passes. In the present embodiment, the intermediate fin projection 122C is provided
not at a position where the first outer fin projection 122B-1 and the second outer
fin projection 122B-2 are closest to each other but at a place where there is a relatively
large gap between the first outer fin projection 122B-1 and the second outer fin projection
122B-2. By thus reducing a flat surface of the fin base surface 121 by providing an
intermediate fin projection 122C extending along the longitudinal direction of the
fin 12, improvement in longitudinal strength of the fin 12 can be brought about. Further,
a long portion of the intermediate fin projection 122C makes it easy for air to make
contact with the surface of the fin 12, bringing about further improvement in heat
transfer coefficient.
[0085] Further, in the heat exchanger 100 according to the present embodiment, assuming
that a transverse direction of the plurality of fins 12 is a third direction X crossing
the first direction Y and the second direction Z, the intermediate fin projection
122C includes a first raised portion 122c-1 extending in the second direction Z, the
first raised portion 122c-1 being raised from the fin base surface 121, and a second
raised portion 122c-2 extending parallel to the first raised portion 122c-1, the second
raised portion 122c-2 raised from the fin base surface 121. In the second direction
Z, the first raised portion 122c-1 is greater in length than the second raised portion
122c-2. In the third direction X, a distance between the first raised portion 122c-1
and the center line CL is longer than a distance between the second raised portion
122c-2 and the center line CL. Further, in the second direction Z, the first raised
portion 122c-1 includes a first end 122c-1a provided adjacent to the first outer fin
projection 122B-1 and a second end 122c-1b provided adjacent to the second outer fin
projection 122B-2. Further, in the second direction Z, the second raised portion 122c-2
includes a first end 122c-2a provided adjacent to the first outer fin projection 122B-1
and a second end 122c-2b provided adjacent to the second outer fin projection 122B-2.
A first virtual line VL1 passing through the first end 122c-1a of the first raised
portion 122c-1 and the first end 122c-2a of the second raised portion 122c-2 does
not cross the first outer fin projection 122B-1. Further, a second virtual line VL2
passing through the second end 122c-1b of the first raised portion 122c-1 and the
second end 122c-2b of the second raised portion 122c-2 does not cross the second outer
fin projection 122B-2.
[0086] This configuration makes it possible to secure flat regions on the fin base surface
121 between the intermediate fin projection 122C and the outer fin projections 122B
for avoiding concentration of stress between the intermediate fin projection 122C
and the outer fin projections 122B in the formation of the fin. This brings about
further improvement in formability of the fin 12.
[Modification 1 of Embodiment 2]
[0087] Fig. 18 is a cross-sectional view showing Modification 1 of a fin 12 of the heat
exchanger 100 according to Embodiment 2. Fig. 18 shows a portion of Modification 1
that corresponds to a cross-section taken along line C-C in Fig. 15. In Modification
1 shown in Fig. 18 too, as in the case of Embodiment 2, the fin 12 includes intermediate
fin projections 122C.
[0088] In the heat exchanger 100 according to Modification 1 of Embodiment 2, in the Y direction,
a direction in which the inner fin projections 122A protrude from the fin base surface
121 and a direction in which the outer fin projections 122B protrude from the fin
base surface 121 are identical to each other. Meanwhile, in the Y direction, the intermediate
fin projection 122C protrudes in a direction opposite to the direction in which the
inner fin projections 122A and the outer fin projections 122B protrude. Other components
and workings are not described here, as they are the same as those of Embodiment 2.
[0089] In the heat exchanger 100 according to Modification 1 of Embodiment 2, in the first
direction Y, a direction in which the inner fin projections 122A protrude from the
fin base surface 121 and a direction in which the intermediate fin projection 122C
protrudes from the fin base surface 121 are opposite to each other. Accordingly, the
inner fin projections 122A are not located in a wake flow portion of the intermediate
fin projection 122C. That is, the inner fin projections 122A are not affected by a
dead water region of the intermediate fin projection 122C. This can result in maximized
utilization of the inner fin projections 122A for heat exchange, bringing about improvement
in heat transfer coefficient on the surface of the fin 12.
[0090] Further, in the first direction Y, a direction in which the outer fin projections
122B protrude from the fin base surface 121 is identical to a direction in which the
inner fin projections 122A protrude. That is, the outer fin projections 122B too are
not located in a wake flow portion of the intermediate fin projection 122C and are
therefore not affected by a dead water region of the intermediate fin projection 122C.
This can result in maximized utilization of the outer fin projections 122B for heat
exchange, bringing about further improvement in heat transfer coefficient on the surface
of the fin 12.
[0091] Further, in Modification 1, the center of gravity of the fin 12 is close to the fin
base surface 121 in the Y direction, as the inner fin projections 122A and the intermediate
fin projection 122C protrude in directions opposite to each other. This brings about
improvement in strength of the fin 12.
[Modification 2 of Embodiment 2]
[0092] Fig. 19 is a partial sectional side view showing Modification 2 of a fin 12 of the
heat exchanger 100 according to Embodiment 2. Fig. 19 shows the surface of the fin
12 and cross-sections of heat transfer tubes 11 parallel to the principal surface
of the fin 12. In Modification 2 shown in Fig. 19 too, as in the case of Embodiment
2, the fin projections 122 include an intermediate fin projection 122C. Fig. 20 is
a cross-sectional view taken along line A-A in Fig. 19.
[0093] As shown in Figs. 19 and 20, in Modification 2 of Embodiment 2, the intermediate
fin projection 122C is provided between the first outer fin projection 122B-1 and
the second outer fin projection 122B-2 to overlap the center line CL. As shown in
Fig. 19, in Modification 2, when viewed from the Y direction, the intermediate fin
projection 122C has the shape of an oblong whose long sides extend in the Z direction.
Differences between Modification 2 and Embodiment 2 lie in the position of the intermediate
fin projection 122C and the shape of the intermediate fin projection 122C. Other components
and workings are not described here, as they are the same as those of Embodiment 1.
[0094] In Modification 2, the intermediate fin projection 122C overlaps the center line
CL between the first outer fin projection 122B-1 and the second outer fin projection
122B-2. The distance between the first raised portion 122c-1 and the center line CL
and the distance between the second raised portion 122c-2 and the center line CL are
equal to each other. Further, the first raised portion 122c-1 and the second raised
portion 122c-2 are equal in length to each other. In Fig. 19, the first raised portion
122c-1 is the left long side as seen from the front of the surface of paper, and the
second raised portion 122c-2 is the right long side as seen from the front of the
surface of paper.
[0095] In Modification 2, the intermediate fin projection 122c is located in a portion in
which the distance between the first outer fin projection 122B-1 and the second outer
fin projection 122B-2 is shortest in the Z direction. In a case in which the distance
between adjacent heat transfer tubes 11 are relatively long, providing an intermediate
fin projection 122C as in the case of Modification 2 brings about improvement in longitudinal
strength of the fin 12 and improvement in heat transfer coefficient of the surface
of the fin 12.
[Modification 3 of Embodiment 2]
[0096] Fig. 21 is a partial sectional side view showing Modification 3 of a fin 12 of the
heat exchanger 100 according to Embodiment 2. Fig. 21 shows the surface of the fin
12 and cross-sections of heat transfer tubes 11 parallel to the principal surface
of the fin 12. In Modification 3 shown in Fig. 21 too, as in the case of Embodiment
2, the fin projections 122 include an intermediate fin projection 122C. Fig. 22 is
a cross-sectional view taken along line A-A in Fig. 21.
[0097] As shown in Figs. 21 and 22, in Modification 3 of Embodiment 2, the intermediate
fin projection 122C is provided between the first outer fin projection 122B-1 and
the second outer fin projection 122B-2 to cross the center line CL. The intermediate
fin projection 122C has a portion elongated in the X direction. In Fig. 21, in the
X direction, the intermediate fin projection 122C is larger in diameter than the first
outer fin projection 122B-1 and the second outer fin projection 122B-2. However, in
the X direction, the intermediate fin projection 122C may be larger in diameter than
or equal in diameter to the first outer fin projection 122B-1 and the second outer
fin projection 122B-2. Differences between Modification 3 and Embodiment 2 lie in
that the intermediate fin projection 122C is provided to cross the center line CL
and in the shape of the intermediate fin projection 122C. Other components and workings
are not described here, as they are the same as those of Embodiment 2.
[0098] In Modification 3, an intermediate fin projection 122C extending along the X direction,
which is the transverse direction of the fin 12, is provided between the first outer
fin projection 122B-1 and the second outer fin projection 122B-2 to cross the center
line CL. Further, portions of the first and second raised portions 122c-1 and 122c-2
that extend along the Z direction, which is the longitudinal direction of the fin
12, are shorter than portions of the first and second raised portions 122c-1 and 122c-2
that extend along the X direction. That is, in Modification 3, the intermediate fin
projection 122C, unlike the intermediate fin projections 122C in Embodiment 2, does
not have a portion elongated along the longitudinal direction of the fin 12. However,
in Modification 3 too, providing the intermediate fin projection 122C brings about
improvement in longitudinal strength of the fin 12. Further, in Modification 3, the
intermediate fin projection 122C makes it easy for air to make contact with the surface
of the fin 12, as the intermediate fin projection 122C has a portion elongated in
the X direction, in which air flows in. This brings about improvement in heat transfer
coefficient on the surface of the fin 12.
[Modification 4 of Embodiment 2]
[0099] Fig. 23 is a partial sectional side view showing Modification 4 of a fin 12 of the
heat exchanger 100 according to Embodiment 2. Fig. 23 shows the surface of the fin
12 and cross-sections of heat transfer tubes 11 parallel to the principal surface
of the fin 12. In Modification 4 shown in Fig. 23 too, as in the case of Embodiment
2, the fin projections 122 include an intermediate fin projection 122C. Fig. 24 is
a cross-sectional view taken along line A-A in Fig. 23.
[0100] As shown in Figs. 23 and 24, in Modification 4 of Embodiment 2, the intermediate
fin projection 122C is provided between the first outer fin projection 122B-1 and
the second outer fin projection 122B-2 to overlap the center line CL. As shown in
Fig. 23, in Modification 4, when viewed from the Y direction, the intermediate fin
projection 122C has a circular shape. As shown Fig. 24, the intermediate fin projection
122C protrudes in a semispherical shape from the fin base surface 121. Differences
between Modification 4 and Embodiment 2 lie in the position of the intermediate fin
projection 122C and the shape of the intermediate fin projection 122C. Other components
and workings are not described here, as they are the same as those of Embodiment 2.
[0101] In Modification 4, the intermediate fin projection 122C overlaps the center line
CL between the first outer fin projection 122B-1 and the second outer fin projection
122B-2. A portion of the intermediate fin projection 122C in Modification 4 elongated
along the longitudinal direction of the fin 12 is not as long as portions of the intermediate
fin projections 122C in Embodiment 2 elongated along the longitudinal direction of
the fin 12. However, in Modification 4 too, providing the intermediate fin projection
122C brings about improvement in longitudinal strength of the fin 12 and improvement
in heat transfer coefficient of the surface of the fin 12.
[Modification 5 of Embodiment 2]
[0102] Fig. 25 is a partial sectional side view showing Modification 5 of a fin 12 of the
heat exchanger 100 according to Embodiment 2. Fig. 25 shows the surface of the fin
12 and cross-sections of heat transfer tubes 11 parallel to the principal surface
of the fin 12. In Modification 5 shown in Fig. 25 too, as in the case of Embodiment
2, the fin projections 122 include intermediate fin projections 122C. Fig. 26 is a
cross-sectional view taken along line C-C in Fig. 25.
[0103] As shown in Fig. 25, in Modification 5 of Embodiment 2, each of the intermediate
fin projections 122C is configured such that the first raised portion 122c-1 and the
second raised portion 122c-2 are equal in length to each other. In the aforementioned
Embodiment 2, as shown in Fig. 15, a case has been described in which the first raised
portion 122c-1 is greater in length than the second raised portion 122c-2. Differences
between Modification 5 and Embodiment 2 lie in a relationship in length between the
first raised portion 122c-1 and the second raised portion 122c-2. Other components
and workings are not described here, as they are the same as those of Embodiment 2.
[0104] In Modification 5, the first virtual line VL1 crosses the first outer fin projection
122B-1. Further, the second virtual line VL2 crosses the second outer fin projection
122B-2. In a case in which the distance between the first outer fin projection 122B-1
and the second outer fin projection 122B-2 is secured in the Z direction, intermediate
fin projections 122C shaped as shown in Modification 5 may be provided. Providing
the intermediate fin projections 122C of Modification 5 brings about improvement in
longitudinal strength of the fin 12 and improvement in heat transfer coefficient of
the surface of the fin 12.
[Modification 6 of Embodiment 2]
[0105] Fig. 27 is a partial sectional side view showing Modification 6 of a fin 12 of the
heat exchanger 100 according to Embodiment 2. Fig. 27 shows the surface of the fin
12 and cross-sections of heat transfer tubes 11 parallel to the principal surface
of the fin 12. In Modification 6 shown in Fig. 27 too, as in the case of Embodiment
2, the fin projections 122 include intermediate fin projections 122C. Fig. 28 is a
cross-sectional view taken along line C-C in Fig. 27.
[0106] As shown in Fig. 27, in Modification 6 of Embodiment 2, when viewed from Y direction,
the intermediate fin projections 122C have T shapes laid down 90 degrees. Therefore,
as shown in Fig. 28, the intermediate fin projections 122C have portions elongated
in the X direction. Differences between Modification 6 and Embodiment 2 lie in the
shapes of the intermediate fin projections 122C. Other components and workings are
not described here, as they are the same as those of Embodiment 2.
[0107] In Modification 6, the first virtual line VL1 crosses the first outer fin projection
122B-1. Further, the second virtual line VL2 crosses the second outer fin projection
122B-2. Furthermore, portions of the intermediate fin projections 122C elongated in
the X direction are located between the first outer fin projection 122B-1 and the
second outer fin projection 122B-2. Each of the intermediate fin projections 12C of
Modification 6 includes a portion linearly extending along the longitudinal direction
(Z direction) of the fin 12 and a portion linearly extending along the transverse
direction (X direction). Providing the intermediate fin projections 122C of Modification
6 brings about longitudinal strength of the fin 12. Furthermore, the intermediate
fin projections 122C make it easy for air to make contact with the surface of the
fin 12, as the intermediate fin projections 122C have portions elongated in the X
direction, in which air flows in. Therefore, Modification 6 can bring about further
improvement in heat transfer coefficient on the surface of the fin 12 than Embodiment
2.
[Modification 7 of Embodiment 2]
[0108] Fig. 29 is a partial sectional side view showing Modification 7 of a fin 12 of the
heat exchanger 100 according to Embodiment 2. Fig. 29 shows the surface of the fin
12 and cross-sections of heat transfer tubes 11 parallel to the principal surface
of the fin 12. In Modification 7 shown in Fig. 29 too, as in the case of Embodiment
2, the fin projections 122 include intermediate fin projections 122C. Fig. 30 is a
cross-sectional view taken along line C-C in Fig. 29.
[0109] As shown in Fig. 29, in Modification 7 of Embodiment 2, the intermediate fin projections
122C include first intermediate fin projections 122C-1 and second intermediate fin
projections 122C-2. The first intermediate fin projections 122C-1 and the second intermediate
fin projections 122C-2 have the shapes of oblongs whose long sides extend in the Z
direction when viewed from the Y direction. Differences between Modification 7 and
Embodiment 2 lie in that in Modification 7, the intermediate fin projections 122C
include the first intermediate fin projections 122C-1 and the second intermediate
fin projections 122C-2. Further, the shapes of the intermediate fin projections 122C
in Embodiment 2 and the shapes of the first intermediate fin projections 122C-1 and
the second intermediate fin projections 122C-2 in Modification 7 are different from
each other. Other components and workings are not described here, as they are the
same as those of Embodiment 2.
[0110] In the following description, the first intermediate fin projections 122C-1 and the
second intermediate fin projections 122C-2 are referred to simply as "intermediate
fin projections 122C" in a case in which there is no particular need to distinguish
between them. The following description uses the noun "intermediate fin projection
122C" in either the singular form or the plural form. Further, as for the first raised
portions 122c-1 too, the first raised portions 122c1-1 of the first intermediate fin
projections 122C-1 and the first raised portions 122c2-1 of the second intermediate
fin projections 122C-2 are referred to simply as "first raised portions 122c-1" in
a case in which there is no particular need to distinguish between them. Furthermore,
as for the second raised portions 122c-2 too, the second raised portions 122c1-2 of
the first intermediate fin projections 122C-1 and the first raised portions 122c2-2
of the second intermediate fin projections 122C-2 are referred to simply as "second
raised portions 122c-2" in a case in which there is no particular need to distinguish
between them. The following description uses each of the nouns "first raised portion
122c-1" and "second raised portion 122c-2" in either the singular form or the plural
form.
[0111] The first intermediate fin projections 122C-1 and the second intermediate fin projections
122C-2 are described with reference to Fig. 29. Each of the first intermediate fin
projections 122C-1 is configured such that the first raised portion 122c1-1 and the
second raised portion 122c1-2 are equal in length to each other. Further, each of
the second intermediate fin projections 122C-2 is configured such that the first raised
portion 122c2-1 and the second raised portion 122c2-2 are equal in length to each
other. It should be noted that differences between the intermediate fin projections
122C in Embodiment 2 and the intermediate fin projections 122C in Modification 7 lie
in relationships in length between the first raised portions 122c-1 and the second
raised portions 122c-2.
[0112] Further, the number of first intermediate fin projections 122C-1 is not limited to
2, although two first intermediate fin projections 122C-1 are provided in Fig. 29.
One first intermediate fin projection 122C-1 may be provided, or three or more first
intermediate fin projections 122C-1 may be provided. Further, the number of second
intermediate fin projections 122C-2 is not limited to 2, although two second intermediate
fin projections 122C-2 are provided in Fig. 29. One second intermediate fin projection
122C-2 may be provided, or three or more second intermediate fin projections 122C-2
may be provided.
[0113] Further, the distance between each of the first intermediate fin projections 122C-1
and the center line CL is longer than the distance between each of the second intermediate
fin projections 122C-2 and the center line CL. Further, the first raised portions
122c1-1 of the first intermediate fin projections 122C-1 are greater in length than
the first raised portions 122c2-1 of the second intermediate fin projections 122C-2.
That is, the first intermediate fin projections 122C-1 are larger than the second
intermediate fin projections 122C-2.
[0114] As mentioned above, in Modification 7, the first intermediate fin projections 122C-1
and the second intermediate fin projections 122C-2, which linearly extend along the
longitudinal direction of the fin 12, are arranged along the transverse direction
of the fin. In Modification 7, providing the first intermediate fin projections 122C-1
and the second intermediate fin projections 122C-2 brings about improvement in longitudinal
strength of the fin 12 and improvement in heat transfer coefficient of the surface
of the fin 12.
[Modification 8 of Embodiment 2]
[0115] Fig. 31 is a partial sectional side view showing Modification 8 of a fin 12 of the
heat exchanger 100 according to Embodiment 2. Fig. 31 shows the surface of the fin
12 and cross-sections of heat transfer tubes 11 parallel to the principal surface
of the fin 12. In Modification 8 shown in Fig. 31 too, as in the case of Embodiment
2, the fin projections 122 include intermediate fin projections 122C. Fig. 32 is a
cross-sectional view taken along line C-C in Fig. 31.
[0116] As shown in Fig. 31, in Modification 8 of Embodiment 2, the intermediate fin projections
122C include first intermediate fin projections 122C-1 and second intermediate fin
projections 122C-2. The first intermediate fin projections 122C-1 have the shapes
of oblongs whose long sides extend in the Z direction when viewed from the Y direction.
Further, the second intermediate fin projections 122C-2 have the shapes of circles
when viewed from the Y direction. Differences between Modification 8 and Embodiment
2 lie in that in Modification 8, the intermediate fin projections 122C include the
first intermediate fin projections 122C-1 and the second intermediate fin projections
122C-2. Further, the shapes of the intermediate fin projections 122C in Embodiment
2 and the shapes of the first intermediate fin projections 122C-1 and the second intermediate
fin projections 122C-2 in Modification 8 are different from each other. Other components
and workings are not described here, as they are the same as those of Embodiment 2.
[0117] The first intermediate fin projections 122C-1 and the second intermediate fin projections
122C-2 are described with reference to Fig. 31. Each of the first intermediate fin
projections 122C-1 is configured such that the first raised portion 122c1-1 and the
second raised portion 122c1-2 are equal in length to each other. The distance between
each of the first intermediate fin projections 122C-1 and the center line CL is longer
than the distance between each of the second intermediate fin projections 122C-2 and
the center line CL. It should be noted that differences between the intermediate fin
projections 122C in Embodiment 2 and the intermediate fin projections 122C in Modification
8 lie in relationships in length between the first raised portions 122c-1 and the
second raised portions 122c-2.
[0118] Further, the number of first intermediate fin projections 122C-1 is not limited to
2, although two first intermediate fin projections 122C-1 are provided in Fig. 31.
One first intermediate fin projection 122C-1 may be provided, or three or more first
intermediate fin projections 122C-1 may be provided. Further, the number of second
intermediate fin projections 122C-2 is not limited to 2, although two second intermediate
fin projections 122C-2 are provided in Fig. 31. One second intermediate fin projection
122C-2 may be provided, or three or more second intermediate fin projections 122C-2
may be provided.
[0119] As mentioned above, in Modification 8, the first intermediate fin projections 122C-1,
which linearly extend along the longitudinal direction of the fin 12, are provided.
Further, at positions where the distance between the first outer fin projection 122B-1
and the second outer fin projection 122B2 is relatively short, the circular second
intermediate fin projections 122C-2, whose lengths along the longitudinal direction
of the fin 12 are relatively short, are provided to reduce the area of a flat portion
of the fin 12. In Modification 8, providing the first intermediate fin projections
122C-1 and the second intermediate fin projections 122C-2 brings about improvement
in longitudinal strength of the fin 12 and improvement in heat transfer coefficient
of the surface of the fin 12.
[0120] As mentioned above, the heat exchanger 100 of any of Embodiment 1, Embodiment 2,
and the modifications thereof can be provided in the refrigeration cycle apparatus
1 shown in Fig. 3. In that case, in the refrigeration cycle apparatus 1, the fin projections
122 provided on each of the fins 12 of the heat exchanger 100 brings about an increase
in longitudinal direction of the fin 12 and improvement in formability of the fin.
This brings about improvement in manufacturability of the heat exchanger 100, resulting
in improvement in manufacturability of the refrigeration cycle apparatus 1 as a whole.
Further, the fin projections 122 provided on each of the fins 12 of the heat exchanger
100 make it easy for air to make contact with the surface of the fin 12. This brings
about improvement in heat transfer coefficient of the heat exchanger 100, resulting
in improvement in energy efficiency of the refrigeration cycle apparatus 1 as a whole.
[0121] While the foregoing has described Embodiment 1, Embodiment 2, and the modifications
thereof, the heat exchanger 100 and the refrigeration cycle apparatus 1 are not limited
to Embodiment 1, Embodiment 2, or the modifications thereof and may be altered or
applied in various ways without departing from the scope of the disclosure. Embodiment
1, Embodiment 2, and the modifications thereof may be combined with one another to
such an extent as not to impair the functions or structures of the embodiments or
the modifications.
Reference Signs List
[0122] 1: refrigeration cycle apparatus, 2: heat source side unit, 3: load side unit, 4:
compressor, 5: flow switching device, 6: expansion valve, 7A: air-sending device,
7B: air-sending device, 7a: fan motor, 7b: fan, 8: refrigerant pipe, 9A: controller,
9B: controller, 11: heat transfer tube, 11A: heat transfer tube, 11B: heat transfer
tube, 11a: U-tube, 12: fin, 12a: leading edge, 12b: trailing edge, 12c: through hole,
12d: fin collar, 100: heat exchanger, 100A: heat exchanger, 100B: heat exchanger,
121: fin base surface, 121A: first flat portion, 121B: second flat portion, 122: fin
projection, 122A: inner fin projection, 122A-1 : first inner fin projection, 122A-2:
second inner fin projection, 122B: outer fin projection, 122B-1 : first outer fin
projection, 122B-2: second outer fin projection, 122B-3: third outer fin projection,
122C: intermediate fin projection, 122C-1 : first intermediate fin projection, 122C-2:
second intermediate fin projection, 122c-1 : first raised portion, 122c-1a: first
end, 122c-1b: second end, 122c-2: second raised portion, 122c-2a: first end, 122c-2b:
second end, 122c1-1 : first raised portion, 122c1-1a: first end, 122c1-1b: second
end, 122c1-2: second raised portion, 122c1-2a: first end, 122c1-2b: second end, 122c2-1
: first raised portion, 122c2-1a: first end, 122c2-1b: second end, 122c2-2: second
raised portion, 122c2-2a: first end, 122c2-2b: second end, 122D: additional fin projection,
Y: first direction, Z: second direction, X: third direction, CL: center line, VL1
: first virtual line, VL2: second virtual line