TECHNICAL FIELD
[0001] The present invention relates to a heat exchanger and a refrigeration cycle apparatus.
BACKGROUND ART
[0002] During the heating operation, refrigerant flowing in a heat transfer tube and air
flowing around the heat transfer tube exchange heat with each other in an outdoor
heat exchanger, and thereby, moisture in the air may be condensed into condensation
water on the surface of the outdoor heat exchanger. When the temperature of the outdoor
unit heat exchanger is low, the condensation water is frozen on the surface of the
outdoor unit heat exchanger and becomes frost. Since the condensation water accumulates
in a lower part of the heat exchanger, the lower part of the heat exchanger is particularly
affected by the frost.
[0003] According to the outdoor unit disclosed in
Japanese Patent Laying-Open No. 2004-347135, in order to prevent frost from being formed in the lower part of the outdoor heat
exchanger, an overcooling heat exchange member configured to excessively cool the
liquid refrigerant condensed in the indoor heat exchanger during the heating operation
is located on the windward side of the lower part of the outdoor heat exchanger. A
part of the heat exchange member which operates as an evaporator in the outdoor heat
exchanger during the heating operation is located on the leeward side of the overcooling
heat exchange member.
CITATION LIST
PATENT LITERATURE
SUMMARY OF INVENTION
TECHNICAL PROBLEM
[0005] In the outdoor heat exchanger described above, since heat is exchanged between the
overcooling heat exchange member and another heat exchange member located on the leeward
side of the overcooling heat exchange member, the amount of heat exchanged between
each heat exchange member and air is reduced, which deteriorates the performance of
the outdoor heat exchanger.
[0006] A main object of the present invention is to provide a heat exchanger capable of
preventing the formation of frost while preventing the performance thereof from being
deteriorated by frost as compared with a conventional outdoor heat exchanger.
SOLUTION TO PROBLEM
[0007] The heat exchanger according to the present invention includes a plurality of heat
transfer tubes. The plurality of heat transfer tubes include at least one first heat
transfer tube configured to extend in a first direction intersecting a vertical direction,
and at least one second heat transfer tube which is located above the at least one
first heat transfer tube and configured to extend in the first direction. A first
air passage is formed in a region adjacent to the at least one first heat transfer
tube in the vertical direction and is configured to extend in a second direction intersecting
both the vertical direction and the first direction. A second air passage is formed
in a region adjacent to the at least one second heat transfer tube in the vertical
direction and is configured to extend in the second direction. The at least one first
heat transfer tube is connected in series to the at least one second heat transfer
tube. The flow path cross-sectional area of the at least one first heat transfer tube
is smaller than the flow path cross-sectional area of the at least one second heat
transfer tube. When viewed from the second direction, the projected area of the first
air passage is greater than the projected area of the second air passage.
ADVANTAGEOUS EFFECTS OF INVENTION
[0008] According to the present invention, it is possible to provide a heat exchanger capable
of preventing the formation of frost while preventing the performance thereof from
being deteriorated by the frost as compared with a conventional outdoor heat exchanger.
BRIEF DESCRIPTION OF DRAWINGS
[0009]
Fig. 1 is a view illustrating a refrigeration cycle apparatus according to a first
embodiment;
Fig. 2(A) is a view illustrating a heat exchanger according to the first embodiment;
Fig. 2(B) is a view explaining the projected area of a first air passage and a second
air passage of the heat exchanger illustrated in Fig. 2(A) when viewed from a second
direction;
Fig. 3 is a cross-sectional view illustrating a first heat transfer tube of the heat
exchanger according to the first embodiment;
Fig. 4 is a cross-sectional view illustrating a second heat transfer tube of the heat
exchanger according to the first embodiment;
Fig. 5 is a view illustrating a heat exchanger according to a second embodiment;
Fig. 6 is a view illustrating a heat exchanger according to a third embodiment; and
Fig. 7 is a view illustrating a heat exchanger according to a fourth embodiment.
DESCRIPTION OF EMBODIMENTS
[0010] Hereinafter, embodiments of the present invention will be described with reference
to the drawings. In the drawings, the same or corresponding portions are denoted by
the same reference numerals, and the description thereof will not be repeated in principle.
First Embodiment
<Configuration of Refrigeration Cycle Apparatus>
[0011] As illustrated in Fig. 1, a refrigeration cycle apparatus 100 according to a first
embodiment includes a refrigerant circuit in which refrigerant is circulated. The
refrigerant circuit includes a compressor 101, a four-way valve 102 which serves as
a flow path switching unit, a decompressor 103, a first heat exchanger 1, and a second
heat exchanger 104. The refrigeration cycle apparatus 100 further includes a first
fan 105 configured to blow air to the first heat exchanger 1 and a second fan 106
configured to blow air to the second heat exchanger 104.
[0012] The compressor 101 is provided with a discharge port configured to discharge refrigerant
and a suction port configured to suck refrigerant. The decompressor 103 may be, for
example, an expansion valve. The decompressor 103 is connected to a first inlet/outlet
6 of the first heat exchanger 1. The first fan 105 creates an airflow in a second
direction B which will be described later.
[0013] The four-way valve 102 is provided with a first port P1 connected to the discharge
port of the compressor 101 via a discharge pipe, a second port P2 connected to the
suction port of the compressor 101 via a suction pipe, a third opening P3 connected
to a second inlet/outlet 7 and a third inlet/outlet 8 of the first heat exchanger
1, and a fourth opening P4 connected to the second heat exchanger 104. The four-way
valve 102 is configured to switch between a first state in which the first heat exchanger
1 operates as a condenser while the second heat exchanger 104 operates as an evaporator,
and a second state in which the second heat exchanger 104 operates as a condenser
while the first heat exchanger 1 operates as an evaporator. The arrows in solid line
as illustrated in Fig. 1 indicate a flow direction of refrigerant circulated in the
refrigerant circuit when the refrigeration cycle apparatus 100 is operating in the
second state, and the arrows in dotted line as illustrated in Fig. 1 indicate a flow
direction of refrigerant circulated in the refrigerant circuit when the refrigeration
cycle apparatus 100 is operating in the first state.
<Configuration of First Heat Exchanger>
[0014] As illustrated in Figs. 2(A) and 2(B), the first heat exchanger 1 mainly includes,
for example, a plurality of fins 2, a plurality of heat transfer tubes 3, 4 and 5,
and a distributor 10. The first heat exchanger 1 is configured to exchange heat between
refrigerant flowing in each of the plurality of first heat transfer tubes 3, 4 and
5 in a first direction A and air flowing through the plurality of fins 2 in a second
direction B. The first direction A intersects the second direction B, and may be,
for example, orthogonal to the second direction B. The first direction A and the second
direction B both intersect a vertical direction C, and each may be, for example, a
horizontal direction.
[0015] As illustrated in Figs. 2(A) and 2(B), each of the plurality of fins 2 extends in
the vertical direction C and the second direction B, and the plurality of fins 2 are
spaced from each other in the first direction A.
[0016] The plurality of heat transfer tubes 3, 4 and 5 are composed of a plurality of first
heat transfer tubes 3, a plurality of second heat transfer tubes 4, and a plurality
of third heat transfer tubes 5. The plurality of first heat transfer tubes 3, the
plurality of second heat transfer tubes 4, and the plurality of third heat transfer
tubes 5 are configured to extend in the first direction A and are spaced from each
other in the vertical direction C.
[0017] As illustrated in Fig. 2(A), the plurality of first heat transfer tubes 3 are arranged
below the plurality of second heat transfer tubes 4 and the plurality of third heat
transfer tubes 5. Among the plurality of heat transfer tubes provided in the first
heat exchanger 1, at least one first heat transfer tube 3 is arranged at the lowest
position. The plurality of first heat transfer tubes 3 are not aligned with the plurality
of second heat transfer tubes 4 in the second direction B. The plurality of third
heat transfer tubes 5 are located above the plurality of second heat transfer tubes
4.
[0018] As illustrated in Fig. 2(A), the plurality of first heat transfer tubes 3 are connected
in series to each other via a first connection member 11. The plurality of second
heat transfer tubes 4 are connected in series to each other via a second connection
member 12. The plurality of third heat transfer tubes 5 are connected in series to
each other via a third connection member 13.
[0019] As illustrated in Fig. 2(A), the plurality of first heat transfer tubes 3 are connected
in series to the distributor 10 via a fourth connection member 21. The plurality of
second heat transfer tubes 4 are connected in series to the distributor 10 via a fifth
connection member 22. The plurality of third heat transfer tubes 5 are connected in
series to the distributor 10 via a sixth connection member 23. Each of the first connection
member 11, the second connection member 12, the third connection member 13, the fourth
connection member 21, the fifth connection member 22, and the sixth connection member
23 is formed as a connection tube that connects two inlets/outlets in series to each
other. In Fig. 2, each first connection member 11 indicated by a solid line is connected
to one end of each first heat transfer tube 3, each second connection member 12 indicated
by a solid line is connected to one end of each second heat transfer tube 4, and each
third connection member 13 indicated by a solid line is connected to one end of each
third heat transfer tube 5; and each first connection member 11 indicated by a dotted
line is connected to the other end of each first heat transfer tube 3, each second
connection member 12 indicated by a dotted line is connected to the other end of each
second heat transfer tube 4, and each third connection member 13 indicated by a dotted
line is connected to the other end of each third heat transfer tube 5.
[0020] As illustrated in Fig. 2(A), the distributor 10 includes a first port P5 connected
to the first heat transfer tube 3 via the fourth connection member 21, a second port
P6 connected to the second heat transfer tube 4 via the fifth connection member 22,
and a third port P7 connected to the third heat transfer tube 5 via the sixth connection
member 23. The first port P5 is arranged below both the second port P6 and the third
port P7. The distributor 10 further includes a refrigerant flow path which connects
the first port P5 to the second port P6, and a refrigerant flow path which connects
the first port P5 to the third port P7.
[0021] The plurality of first heat transfer tubes 3 connected in series to each other via
the first connection member 11 constitute a first refrigerant flow path. The plurality
of second heat transfer tubes 4 connected in series to each other via the second connection
member 12 constitute a second refrigerant flow path. The plurality of third heat transfer
tubes 5 connected in series to each other via the third connection member 13 constitute
a third refrigerant flow path. The first refrigerant flow path is arranged below the
second refrigerant flow path. The third refrigerant flow path is located above the
second refrigerant flow path, for example.
[0022] The first refrigerant flow path is connected in series to both the second refrigerant
flow path and the third refrigerant flow path via the distributor 10. The first heat
transfer tubes 3 are connected in series to both the second heat transfer tubes 4
and the third heat transfer tubes 5 via the distributor 10. The second refrigerant
flow path and the third refrigerant flow path are branched from the first refrigerant
flow path. The second heat transfer tubes 4 and the third heat transfer tubes 5 are
connected to the distributor 10 in parallel with each other.
[0023] One end of the first refrigerant flow path is connected to the first port P5 of the
distributor 10. The other end of the first refrigerant flow path is connected to the
first inlet/outlet 6. One end of the second refrigerant flow path is connected to
the second port P6 of the distributor 10. The other end of the second refrigerant
flow path is connected to the second inlet/outlet 7. One end of the third refrigerant
flow path is connected to the third port P7 of the distributor 10. The other end of
the third refrigerant flow path is connected to the third inlet/outlet 8.
[0024] In the first state, the refrigerant flows from the second inlet/outlet 7 and the
third inlet/outlet 8 into the first heat exchanger 1, after the refrigerant flows
through the second refrigerant flow path and the third refrigerant flow path, the
refrigerant flows through the first refrigerant flow path, and then flows out of the
first heat exchanger 1 from the first inlet/outlet 6. In the second state, the refrigerant
flows from the first inlet/outlet 6 into the first heat exchanger 1, after the refrigerant
flows through the first refrigerant flow path, the refrigerant flows through the second
refrigerant flow path and the third refrigerant flow path, and then flows out of the
first heat exchanger 1 from the second inlet/outlet 7 and the third inlet/outlet 8.
[0025] As illustrated in Fig. 2(A), each of the plurality of first heat transfer tubes 3
has the same configuration. The plurality of first heat transfer tubes 3 include a
first group of first heat transfer tubes 3A spaced from each other in the vertical
direction C, and a second group of first heat transfer tubes 3B spaced from each other
in the vertical direction C and spaced from the first group of first heat transfer
tubes 3A in the second direction B. In other words, the column number of the first
heat transfer tubes 3 arranged in the second direction B is 2 or more. In the first
embodiment, the column number of the first heat transfer tubes 3 arranged in the second
direction B is equal to the column number of the second heat transfer tubes 4 arranged
in the second direction B.
[0026] The first group of first heat transfer tubes 3A and the second group of first heat
transfer tubes 3B are adjacent to each other in the second direction B. When viewed
from the second direction B, at least a part of each first heat transfer tube 3B is
located between two of the first heat transfer tubes 3A adjacent to each other in
the vertical direction. For example, the entire part of each first heat transfer tube
3B is located between two of the first heat transfer tubes 3A adjacent to each other
in the vertical direction. The first group of first heat transfer tubes 3A are connected
in series to each other, for example. The second group of first heat transfer tubes
3B are connected in series to each other, for example. The first group of first heat
transfer tubes 3A are connected in series to the second group of first heat transfer
tubes 3B, for example.
[0027] The lowest first heat transfer tube 3 of the plurality of first heat transfer tubes
3 is the lowest first heat transfer tubes 3A in the first group of first heat transfer
tubes 3A. The lowest first heat transfer tubes 3A in the first group of first heat
transfer tubes 3A is connected to the first inlet/outlet 6. The uppermost first heat
transfer tube 3 of the plurality of first heat transfer tubes 3 is the uppermost first
heat transfer tube 3B in the second group of first heat transfer tubes 3B. The uppermost
first heat transfer tube 3B in the second group of first heat transfer tubes 3B is
connected to the distributor 10 via the fourth connection member 21. The first group
of first heat transfer tubes 3A are located on the windward side of the second group
of first heat transfer tubes 3B.
[0028] As illustrated in Fig. 2(A), each of the plurality of second heat transfer tubes
4 has the same configuration. The plurality of second heat transfer tubes 4 include
a first group of second heat transfer tubes 4A spaced from each other in the vertical
direction C, and a second group of second heat transfer tubes 4B spaced from each
other in the vertical direction C and spaced from the first group of second heat transfer
tubes 4A in the second direction B. In other words, the column number of the plurality
of second heat transfer tubes 4 arranged in the second direction B is 2 or more.
[0029] The first group of second heat transfer tubes 4A and the second group of second heat
transfer tubes 4B are adjacent to each other in the second direction B. When viewed
from the second direction B, at least a part of each second heat transfer tube 4B
is located between two of the second heat transfer tubes 4A adjacent to each other
in the vertical direction. For example, the entire part of each second heat transfer
tube 4B is located between two of the second heat transfer tubes 4A adjacent to each
other in the vertical direction. The first group of second heat transfer tubes 4A
are connected in series to each other, for example. The second group of second heat
transfer tubes 4B are connected in series to each other, for example. The first group
of second heat transfer tubes 4A are connected in series to the second group of second
heat transfer tubes 4B, for example. The first group of second heat transfer tubes
4A are located on the windward side of the second group of second heat transfer tubes
4B.
[0030] The lowest second heat transfer tubes 4 of the plurality of second heat transfer
tubes 4 is the lowest second heat transfer tubes 4A in the first group of second heat
transfer tubes 4A. The lowest second heat transfer tube 4A in the first group of second
heat transfer tubes 4A is connected to the lowest second heat transfer tube 4B in
the second group of second heat transfer tubes 4B via the second connection member
12.
[0031] As illustrated in Fig. 2(A), each of the plurality of third heat transfer tubes 5
has the same configuration. The plurality of third heat transfer tubes 5 include a
first group of third heat transfer tubes 5A spaced from each other in the vertical
direction C, and a second group of third heat transfer tubes 5B spaced from each other
in the vertical direction C and spaced from the first group of third heat transfer
tubes 5A in the second direction B. In other words, the column number of the third
heat transfer tubes 5 arranged in the second direction B is 2 or more.
[0032] The first group of third heat transfer tubes 5A and the second group of third heat
transfer tubes 5B are adjacent to each other in the second direction B. The first
group of third heat transfer tubes 5A are located on the windward side of the second
group of third heat transfer tubes 5B. When viewed from the second direction B, at
least a part of each third heat transfer tube 5B is located between two of the third
heat transfer tubes 5A adjacent to each other in the vertical direction. For example,
the entire part of each third heat transfer tube 5B is located between two of the
third heat transfer tubes 5A adjacent to each other in the vertical direction. The
first group of third heat transfer tubes 5A are connected in series to each other,
for example. The second group of third heat transfer tubes 5B are connected in series
to each other, for example. The first group of third heat transfer tubes 5A are connected
in series to the second group of third heat transfer tubes 5B, for example.
[0033] As illustrated in Fig. 2(B), a plurality of first air passages A1 are formed in a
region adjacent to each first heat transfer tube 3 in the vertical direction C and
configured to extend in the second direction B. Each first air passage A1 is a minimum
unit of the entire air passage formed in a region adjacent to each first heat transfer
tube 3 in the vertical direction C. The plurality of first air passages A1 are arranged
side by side in the first direction A. Two of the first air passages A1 adjacent to
each other in the first direction are partitioned by a fin 2. When viewed from the
second direction B, each first air passage A1 is located between the first heat transfer
tubes 3A and 3B adjacent to each other in the vertical direction C. A width D3 of
each first air passage A1 in the vertical direction C is equal to a gap between the
first heat transfer tubes 3A and 3B adjacent to each other in the vertical direction
C when viewed from the second direction B, but is smaller than a gap D1 (see Fig.
2(A)) between two of the first heat transfer tubes 3 arranged side by side in the
vertical direction C.
[0034] Among the plurality of air passages formed in a region adjacent to each of the plurality
of heat transfer tubes 3, 4 and 5 in the vertical direction C and configured to extend
in the second direction B, an air passage located at the lowest position constitutes
the first air passage A1.
[0035] As illustrated in Fig. 2(B), a plurality of second air passages A2 are formed in
a region adjacent to each second heat transfer tube 4 in the vertical direction C
and configured to extend in the second direction B. Each second air passage A2 is
a minimum unit of the entire air passage formed in a region adjacent to each second
heat transfer tube 4 in the vertical direction C. The second air passages A2 are arranged
side by side in the first direction A. Two of the second air passages A2 adjacent
to each other in the first direction are partitioned by a fin 2. Each second air passage
A2 is located above each first air passage A1. When viewed from the second direction
B, each second air passage A2 is located between the second heat transfer tubes 4A
and 4B adjacent to each other in the vertical direction C. A width D4 of the second
air passage A2 in the vertical direction C is equal to a gap between the second heat
transfer tubes 4A and 4B adjacent to each other in the vertical direction C when viewed
from the second direction B, but is smaller than a gap D2 (see Fig. 2(A)) between
two of the second heat transfer tubes 4 arranged side by side in the vertical direction
C.
[0036] As illustrated in Fig. 2(B), when viewed from the second direction B, the projected
area of each first air passage A1 is greater than the projected area of each second
air passage A2. In other words, the width of each first air passage A1 in the vertical
direction C is greater than the width of each second air passage A2 in the vertical
direction C.
[0037] As illustrated in Fig. 2(A), the gap D1 between two of the first heat transfer tubes
3 arranged side by side in the vertical direction C is equal to the gap D2 between
two of the second heat transfer tubes 4 arranged side by side in the vertical direction
C. As illustrated in Figs. 2(A), 3 and 4, a width W1 of each first heat transfer tube
3 in the vertical direction is smaller than a width W2 of each second heat transfer
tube 4 in the vertical direction. Therefore, the gap D3 between the first heat transfer
tubes 3A and 3B in the vertical direction C when viewed from the second direction
B is greater than the gap D4 between the second heat transfer tubes 4A and 4B in the
vertical direction C when viewed from the second direction B. The gap D3 between the
first heat transfer tubes 3A and 3B in the vertical direction C when viewed from the
second direction B is equal to the width of the first air passage A1 in the vertical
direction C. The gap D4 between the second heat transfer tubes 4A and 4B in the vertical
direction C when viewed from the second direction B is equal to the width of each
second air passage A2 in the vertical direction C. Therefore, the width of each first
air passage A1 in the vertical direction C is greater than the width of each second
air passage A2 in the vertical direction C.
[0038] The projected area of each first air passage A1 is obtained by subtracting, from
the projected area of a space between two of the first heat transfer tubes 3 located
on the most windward side and arranged adjacent to each other in the vertical direction
C, the projected area of a first heat transfer tube 3 located between the two first
heat transfer tubes 3. The projected area of each second air passage A2 is obtained
by subtracting, from the projected area of a space between two of the second heat
transfer tubes 4 located on the most windward side and arranged adjacent to each other
in the vertical direction C, the projected area of a second heat transfer tube 4 located
between the two second heat transfer tubes 4.
[0039] As illustrated in Figs. 3 and 4, the flow path cross-sectional area of the refrigerant
in each of the plurality of first heat transfer tubes 3 is smaller than the flow path
cross-sectional area of the refrigerant in each of the plurality of second heat transfer
tubes 4.
[0040] As illustrated in Figs. 2(A), 3 and 4, each of the plurality of first heat transfer
tubes 3 and the plurality of second heat transfer tubes 4 is formed as a circular
tube, for example. As illustrated in Figs. 2(A), 3 and 4, the outer diameter W1 of
each of the plurality of first heat transfer tubes 3 is smaller than the outer diameter
W2 of each of the plurality of second heat transfer tubes 4. The inner diameter of
each of the plurality of first heat transfer tubes 3 is smaller than the inner diameter
of each of the plurality of second heat transfer tubes 4.
[0041] A plurality of third air passages (not shown) are formed in a region adjacent to
each third heat transfer tube 5 in the vertical direction C and configured to extend
in the second direction B. The third air passages are arranged side by side in the
first direction A. Two of the third air passages adjacent to each other in the first
direction are partitioned by a fin 2. Each third air passage is a minimum unit of
the entire air passage formed in a region adjacent to each third heat transfer tube
5 in the vertical direction C. When viewed from the second direction B, each third
air passage is located between the third heat transfer tubes 5A and 5B adjacent to
each other in the vertical direction C. The width of the third air passage in the
vertical direction C is equal to the gap between the third heat transfer tubes 5A
and 5B adjacent to each other in the vertical direction C when viewed from the second
direction B, but is smaller than the gap between two of the third heat transfer tubes
5 arranged side by side in the vertical direction C.
[0042] When viewed from the second direction B, the projected area of each first air passage
A1 is greater than the projected area of each third air passage. The gap between two
of the plurality of first heat transfer tubes 3 adjacent to each other in the vertical
direction is equal to the gap between two of the plurality of third heat transfer
tubes 5 adjacent to each other in the vertical direction. The vertical width W1 of
each first heat transfer tube 3 in the vertical direction is smaller than the vertical
width of each third heat transfer tube 5 in the vertical direction. The flow path
cross-sectional area of the refrigerant in each of the plurality of first heat transfer
tubes 3 is smaller than the flow path cross-sectional area of the refrigerant in each
of the plurality of third heat transfer tubes 5.
[0043] The projected area of each third air passage is equal to the projected area of each
second air passage. The gap between two of the plurality of third heat transfer tubes
5 adjacent to each other in the vertical direction is equal to the gap between two
of the plurality of second heat transfer tubes 4 adjacent to each other in the vertical
direction. The width of each third heat transfer tube 5 in the vertical direction
is equal to the width W2 of each second heat transfer tube 4 in the vertical direction.
The flow path cross-sectional area of the refrigerant in each of the plurality of
third heat transfer tubes 5 is equal to the flow path cross-sectional area of the
refrigerant in each of the plurality of second heat transfer tubes 4.
<Effects>
[0044] In the first heat exchanger 1, the flow path cross-sectional area of the refrigerant
in the first heat transfer tube 3 is smaller than the flow path cross-sectional area
of the refrigerant in the second heat transfer tube 4. In other words, the pressure
loss of the refrigerant flowing in the first heat transfer tube 3 is greater than
the pressure loss of the refrigerant flowing in the second heat transfer tube 4. Therefore,
when the refrigerant flows from the first heat transfer tube 3 into the second heat
transfer tube 4 in the second state, the pressure of the refrigerant flowing in the
first heat transfer tube 3 is higher than the pressure of the refrigerant flowing
in the second heat transfer tube 4. In the second state, the refrigerant flowing through
the first heat transfer tube 3 and the second heat transfer tube 4 is in a gas-liquid
two-phase state, and the pressure of the refrigerant is positively correlated to the
temperature of the refrigerant. Therefore, in the second state, the temperature of
the refrigerant flowing in the first heat transfer tube 3 is higher than the temperature
of the refrigerant flowing in the second heat transfer tube 4.
[0045] Further, in the first heat exchanger 1, when viewed from the second direction B,
the projected area of the first air passage A1 is greater than the projected area
of the second air passage A2. Therefore, the air volume in the first air passage A1
is greater than the air volume in the second air passage A2, which makes it easier
to drain the condensation water in the first air passage A1 to the outside.
[0046] Specifically, in the first heat exchanger 1, the air flowing around the first heat
transfer tube 3 and the refrigerant flowing in the first heat transfer tube 3 prevent
frost from being formed on the first heat transfer tube 3. Therefore, even if the
temperature difference between the temperature of the refrigerant flowing in the first
heat transfer tube 3 and the temperature of the refrigerant flowing in the second
heat transfer tube 4 is smaller than the temperature difference between the temperature
of the overcooling heat exchange member and the temperature of the other heat exchange
members in the conventional heat exchanger mentioned above, it is possible to prevent
frost from being formed on the first heat transfer tube 3 at a capacity equal to or
greater than that of the conventional heat exchanger mentioned above. In other words,
according to the first heat exchanger 1, it is possible to prevent the formation of
frost while preventing the performance thereof from being deteriorated by the frost
as compared with a conventional outdoor heat exchanger.
[0047] Further, in the first heat exchanger 1, an air passage which is located at the lowest
position among the plurality of air passages formed in a region adjacent to each of
the plurality of heat transfer tubes 3, 4 and 5 in the vertical direction C and configured
to extend in the second direction B constitutes the first air passage A1. Frost is
more likely to be formed in the lowest air passage than an upper air passage thereof.
Therefore, according to the first heat exchanger 1 in which the first air passage
A1 is constituted by the lowest air passage, it is possible to effectively prevent
the performance thereof from being deteriorated by the frost.
[0048] Moreover, the first heat exchanger 1 further includes a plurality of third heat transfer
tubes 5 connected to the plurality of first heat transfer tubes 3 in parallel with
the plurality of second heat transfer tubes 4. Therefore, the flow rate of the refrigerant
flowing through each of the first heat transfer tubes 3 is greater than the flow rate
of the refrigerant flowing through each of the second heat transfer tubes 4, which
makes the flow velocity of the refrigerant flowing through each of the first heat
transfer tubes 3 faster than the flow velocity of the refrigerant flowing through
each of the second heat transfer tubes 4. As a result, the pressure loss of the refrigerant
flowing through the first heat transfer tube 3 becomes greater than the pressure loss
of the refrigerant flowing through the second heat transfer tube 4 due to the difference
in the flow path cross-sectional area and the difference in the flow velocity, whereby
the temperature of the refrigerant flowing through the first heat transfer tube 3
becomes higher than the temperature of the refrigerant flowing through the second
heat transfer tube 4 in the second state.
[0049] In the refrigeration cycle apparatus 100, the first heat exchanger 1 is configured
in such a manner that the refrigerant flows from the first heat transfer tube 3 into
the second heat transfer tube 4 in the second state. Thus, it is possible for the
first heat exchanger 1 to prevent the formation of frost while preventing the performance
thereof from being deteriorated by the frost as compared with a conventional outdoor
heat exchanger. As a result, the operation efficiency of the refrigeration cycle apparatus
100 in the second state is improved than that of a refrigeration cycle apparatus equipped
with the conventional outdoor heat exchanger.
Second Embodiment
[0050] As illustrated in Fig. 5, a first heat exchanger 1A according to a second embodiment
has basically the same configuration as the first heat exchanger 1 according to the
first embodiment, but differs from the first heat exchanger 1 according to the first
embodiment in that the gap D1 between two of the first heat transfer tubes 3 adjacent
to each other in the vertical direction C is greater than the gap D2 between two of
the second heat transfer tubes 4 adjacent to each other in the vertical direction
C.
[0051] In this case, the projected area of the first air passage A1 in the first heat exchanger
1A is greater than the projected area of the second air passage A2 in the first heat
exchanger 1A. Further, when the first heat exchanger 1A having the gap D2 is compared
with the first heat exchanger 1 having the same gap D2 according to the first embodiment,
the gap D1 in the first heat exchanger 1A is greater than the gap D1 in the first
heat exchanger 1, whereby the projected area of the first air passage A1 in the first
heat exchanger 1A is greater than the projected area of the first air passage A1 in
the first heat exchanger 1. As a result, it is possible for the first heat exchanger
1A according to the second embodiment to further prevent frost from being formed on
the first heat transfer tube 3 as compared with the first heat exchanger 1 according
to the first embodiment.
Third Embodiment
[0052] As illustrated in Fig. 6, a first heat exchanger 1B according to a third embodiment
has basically the same configuration as the first heat exchanger 1 according to the
first embodiment, but differs from the first heat exchanger 1 according to the first
embodiment in that the column number of the plurality of first heat transfer tubes
3 arranged in the second direction B is smaller than the column number of the plurality
of second heat transfer tubes 4 arranged in the second direction B.
[0053] The column number of the first heat transfer tubes 3 arranged in the second direction
B is 1 or more. The column number of the plurality of second heat transfer tubes 4
arranged in the second direction B is greater than the column number of the plurality
of first heat transfer tubes 3 arranged in the second direction B, and is 2 or more.
[0054] With reference to Fig. 6, a configuration example in which the column number of the
first heat transfer tubes 3 arranged in the second direction B is 1 will be described.
In this configuration, each first air passage A1 is located between two adjacent first
heat transfer tubes 3 arranged side by side in the vertical direction C. Therefore,
the width of the first air passage A1 in the vertical direction C is equal to the
gap D1 between the two adjacent first heat transfer tubes 3 arranged side by side
in the vertical direction C.
[0055] On the other hand, each second air passage A2 is located between the second heat
transfer tubes 4A and 4B adjacent to each other in the vertical direction C when viewed
from the second direction B. The width of the second air passage A2 in the vertical
direction C is equal to the gap between the second heat transfer tubes 4A and 4B adjacent
to each other in the vertical direction C when viewed from the second direction B,
but is smaller than the gap D2 (see Fig. 2(A)) between two of the second heat transfer
tubes 4 arranged side by side in the vertical direction C.
[0056] Thus, even when the gap D1 is equal to the gap D2, the width of the first air passage
A1 in the vertical direction C is twice as great as the width of the second air passage
A2 in the vertical direction C. As a result, the projected area of the first air passage
A1 is twice as great as the projected area of the second air passage A2, whereby the
drainage efficiency of the first air passage A1 is considerably higher than the drainage
efficiency of the second air passage A2.
[0057] When the first heat exchanger 1B according to the third embodiment is compared with
the first heat exchanger 1 according to the first embodiment in which the gap D1 and
the gap D2 are equal to those in the first heat exchanger 1B, the projected area of
the first air passage A1 in the first heat exchanger 1B is greater than the projected
area of the first air passage A1 in the first heat exchanger 1. Thus, the drainage
efficiency of the first air passage A1 in the first heat exchanger 1B becomes higher
than the drainage efficiency of the first air passage A1 in the first heat exchanger
1.
[0058] Moreover, in the first heat exchanger 1 according to the third embodiment, the column
number of the first heat transfer tubes 3 arranged in the second direction B may be
two or more as long as the column number of the first heat transfer tubes 3 arranged
in the second direction B is smaller than the column number of the first heat transfer
tubes 3 arranged in the second direction B. Even in this case, the column number of
the first heat transfer tubes 3 which are located on the most windward side and arranged
between two of the first heat transfer tubes 3 adjacent to each other in the vertical
direction C when viewed from the second direction B is smaller than the column number
of the second heat transfer tubes 4 which are located on the most windward side and
arranged between two of the second heat transfer tubes 4 adjacent to each other in
the vertical direction C.
[0059] As described above, the projected area of each first air passage A1 is obtained by
subtracting, from the projected area of a space between the projected area of two
of the first heat transfer tubes 3 located on the most windward side and arranged
adjacent to each other in the vertical direction C, the projected area of a first
heat transfer tube 3 arranged between the two first heat transfer tubes 3. The projected
area of each second air passage A2 is obtained by subtracting, from the projected
area of a space between two of the second heat transfer tubes 4 located on the most
windward side and arranged adjacent to each other in the vertical direction C, the
projected area of a second heat transfer tube 4 arranged between the two second heat
transfer tubes 4.
[0060] In the first heat exchanger 1B, even if the column number of the first heat transfer
tubes 3 is two or more, since the column number of the first heat transfer tubes 3
is smaller than the column number of the second heat transfer tubes 4, the number
of the first heat transfer tubes 3 arranged between two of the first heat transfer
tubes 3 is smaller than the number of the second heat transfer tubes 4 arranged between
two of the second heat transfer tubes 4. As a result, the projected area of the first
air passage A1 is greater than the projected area of the second air passage A2, and
thereby, the drainage efficiency of the first air passage A1 is higher than the drainage
efficiency of the second air passage A2.
Fourth Embodiment
[0061] As illustrated in Fig. 7, the first heat exchanger 1C according to a fourth embodiment
has basically the same configuration as the first heat exchanger 1A according to the
second embodiment, but differs from the first heat exchanger 1A according to the second
embodiment in that the column number of the plurality of first heat transfer tubes
3 arranged in the second direction B is smaller than the column number of the plurality
of second heat transfer tubes 4 arranged in the second direction B. From another point
of view, the first heat exchanger 1C has basically the same configuration as the first
heat exchanger 1B according to the third embodiment, but differs from the first heat
exchanger 1B according to the third embodiment in that the gap D1 between two of the
first heat transfer tubes 3 adjacent to each other in the vertical direction C is
greater than the gap D2 between two of the second heat transfer tubes 4 adjacent to
each other in the vertical direction C.
[0062] Since the first heat exchanger 1C includes both the configuration of the first heat
exchanger 1A and the configuration of the first heat exchanger 1B, the projected area
of the first air passage A1 of the first heat exchanger 1C is greater than the projected
area of the second air passage A2 of the first heat exchanger 1C, and is greater than
the projected area of the first air passage A1 of the first heat exchanger 1, the
projected area of the first air passage A1 of the first heat exchanger 1A, and the
projected area of the first air passage A1 of the first heat exchanger 1B. As a result,
it is possible for the first heat exchanger 1C to more efficiently prevent frost from
being formed on the first heat transfer tube 3 than the first heat exchanger 1, the
first heat exchanger 1A, and the first heat exchanger 1B.
<Modifications>
[0063] In the first heat exchangers 1, 1A, 1B and 1C, each of the plurality of heat transfer
tubes 3, 4 and 5 is formed as a circular tube, but it is not limited thereto. Each
of the plurality of heat transfer tubes 3, 4 and 5 may be formed as a flat tube.
[0064] Each of the first heat exchangers 1, 1A, 1B and 1C is configured to include a plurality
of first heat transfer tubes 3 and a plurality of second heat transfer tubes 4, but
it is not limited thereto. Each of the first heat exchangers 1, 1A, 1B and 1C may
include one first heat transfer tube 3 and one second heat transfer tube 4.
[0065] Although the embodiments of the present invention have been described above, the
embodiments described above may be modified in various ways. The scope of the present
invention is not limited to the embodiments described above. The scope of the present
invention is defined by the terms of the claims, and is intended to include all modifications
within the meaning and scope equivalent to the terms of the claims.
REFERENCE SIGNS LIST
[0066] 1, 1A, 1B, 1C: first heat exchanger; 2: fin; 3, 3A, 3B: first heat transfer tube;
4, 4A, 4B: second heat transfer tube; 5, 5A, 5B: third heat transfer tube; 6: first
inlet/outlet; 7: second inlet/outlet; 8: third inlet/outlet; 10: distributor; 11:
first connection member; 12: second connection member; 13: third connection member;
21: fourth connection member; 22: fifth connection member; 23: sixth connection member;
100: refrigeration cycle apparatus; 101: compressor; 102: four-way valve; 103: decompressor;
104: second heat exchanger; 105: first fan; 106: second fan
1. A heat exchanger comprising:
a plurality of heat transfer tubes;
the plurality of heat transfer tubes including:
at least one first heat transfer tube configured to extend in a first direction intersecting
a vertical direction; and
at least one second heat transfer tube located above the at least one first heat transfer
tube and configured to extend in the first direction,
a first air passage being formed in a region adjacent to the at least one first heat
transfer tube in the vertical direction and being configured to extend in a second
direction intersecting both the vertical direction and the first direction,
a second air passage being formed in a region adjacent to the at least one second
heat transfer tube in the vertical direction and being configured to extend in the
second direction,
the at least one first heat transfer tube being connected in series to the at least
one second heat transfer tube,
a flow path cross-sectional area of the at least one first heat transfer tube being
smaller than a flow path cross-sectional area of the at least one second heat transfer
tube, and
when viewed from the second direction, a projected area of the first air passage being
greater than a projected area of the second air passage.
2. The heat exchanger according to claim 1, wherein
the at least one first heat transfer tube includes a plurality of the first heat transfer
tubes,
the at least one second heat transfer tube includes a plurality of the second heat
transfer tubes,
the plurality of first heat transfer tubes are spaced from each other in the vertical
direction and connected in series to each other,
the plurality of second heat transfer tubes are spaced from each other in the vertical
direction and connected in series to each other,
the first air passage is located between two of the plurality of first heat transfer
tubes adjacent to each other in the vertical direction, and
the second air passage is located between two of the plurality of second heat transfer
tubes adjacent to each other in the vertical direction.
3. The heat exchanger according to claim 2, wherein
a gap between two of the plurality of first heat transfer tubes adjacent to each other
in the vertical direction is greater than a gap between two of the plurality of second
heat transfer tubes adjacent to each other in the vertical direction.
4. The heat exchanger according to claim 2 or 3, wherein
the column number of the plurality of first heat transfer tubes arranged in the second
direction is smaller than the column number of the plurality of second heat transfer
tubes arranged in the second direction.
5. The heat exchanger according to any one of claims 2 to 4 further comprising:
a plurality of third heat transfer tubes connected to the plurality of first heat
transfer tubes in parallel with the plurality of second heat transfer tubes.
6. The heat exchanger according to any one of claims 1 to 5, wherein among a plurality
of air passages, each of which is formed in a region adjacent to each of the plurality
of heat transfer tubes in the vertical direction and is configured to extend in the
second direction, an air passage located at the lowest position constitutes the first
air passage.
7. A refrigeration cycle apparatus comprising:
a compressor;
a flow path switching unit;
a decompressor;
a first heat exchanger; and
a second heat exchanger,
the flow path switching unit being configured to switch between a first state and
a second state, in the first state, refrigerant flowing through the compressor, the
first heat exchanger, the decompressor, and the second heat exchanger in this order,
and in the second state, the refrigerant flowing through the compressor, the second
heat exchanger, the decompressor, and the first heat exchanger in this order,
the first heat exchanger being the heat exchanger according to any one of claims 1
to 6,
the refrigerant flowing from the at least one second heat transfer tube to the at
least one first heat transfer tube in the first state, and flowing from the at least
one first heat transfer tube to the at least one second heat transfer tube in the
second state.