U.S. patent application number 17/705356 was filed with the patent office on 2022-07-07 for evaporator and refrigeration cycle apparatus including the same.
This patent application is currently assigned to DAIKIN INDUSTRIES, LTD.. The applicant listed for this patent is DAIKIN INDUSTRIES, LTD.. Invention is credited to Tomoki Hirokawa, Ikuhiro Iwata, Ryuhei Kaji, Eiji Kumakura, Takuro Yamada.
Application Number | 20220214085 17/705356 |
Document ID | / |
Family ID | 1000006284201 |
Filed Date | 2022-07-07 |
United States Patent
Application |
20220214085 |
Kind Code |
A1 |
Kumakura; Eiji ; et
al. |
July 7, 2022 |
EVAPORATOR AND REFRIGERATION CYCLE APPARATUS INCLUDING THE SAME
Abstract
An evaporator includes: fins disposed at a predetermined
interval in a fin thickness direction; heat transfer tubes
extending through the fins in the fin thickness direction; and a
first heat exchange section in which, when the heat transfer tubes
are viewed in the fin thickness direction, a center of distribution
of the heat transfer tubes in an airflow direction is disposed on a
leeward side of a center of the fins in the airflow direction. The
evaporator is disposed in a refrigeration cycle apparatus in which
a non-azeotropic refrigerant mixture is enclosed.
Inventors: |
Kumakura; Eiji; (Osaka,
JP) ; Iwata; Ikuhiro; (Osaka, JP) ; Yamada;
Takuro; (Osaka, JP) ; Kaji; Ryuhei; (Osaka,
JP) ; Hirokawa; Tomoki; (Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DAIKIN INDUSTRIES, LTD. |
Osaka |
|
JP |
|
|
Assignee: |
DAIKIN INDUSTRIES, LTD.
Osaka
JP
|
Family ID: |
1000006284201 |
Appl. No.: |
17/705356 |
Filed: |
March 27, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/JP2020/036920 |
Sep 29, 2020 |
|
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17705356 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28F 1/325 20130101;
F25B 39/00 20130101; F25B 39/02 20130101 |
International
Class: |
F25B 39/00 20060101
F25B039/00; F28F 1/32 20060101 F28F001/32 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 30, 2019 |
JP |
2019-180813 |
Claims
1. An evaporator comprising: fins disposed at a predetermined
interval in a fin thickness direction; heat transfer tubes
extending through the fins in the fin thickness direction; and a
first heat exchange section in which, when the heat transfer tubes
are viewed in the fin thickness direction, a center of distribution
of the heat transfer tubes in an airflow direction is on a leeward
side of a center of the fins in the airflow direction, wherein the
evaporator is disposed in a refrigeration cycle apparatus in which
a non-azeotropic refrigerant mixture is enclosed.
2. The evaporator according to claim 1, further comprising a second
heat exchange section in which the center of the distribution of
the heat transfer tubes is on a windward side of the center of the
fins in the airflow direction when the heat transfer tubes are
viewed in the fin thickness direction.
3. The evaporator according to claim 2, further comprising a third
heat exchange section in which the center of the distribution of
the heat transfer tubes coincides with the center of the fins in
the airflow direction when the heat transfer tubes are viewed in
the fin thickness direction.
4. The evaporator according to claim 2, wherein the first heat
exchange section is integral with the second heat exchange
section.
5. The evaporator according to claim 3, wherein the first heat
exchange section is integral with one or more of the second heat
exchange section and the third heat exchange section.
6. An evaporator comprising: fins disposed at a predetermined
interval in a fin thickness direction; heat transfer tubes
extending through the fins in the fin thickness direction; a first
heat exchange section in which a distance from a windward-side end
of one of the heat transfer tubes disposed on a most windward side
in an airflow direction to a windward-side end of the fins is a
first dimension; and a second heat exchange section in which a
distance from a windward-side end of one of the heat transfer tubes
disposed on a most windward side in the airflow direction to a
windward-side end of the fins is a second dimension smaller than
the first dimension, wherein, the evaporator is disposed in a
refrigeration cycle apparatus in which a non-azeotropic refrigerant
mixture is enclosed.
7. The evaporator according to claim 6, further comprising a third
heat exchange section in which a first distance is equal to a
second distance, wherein, the first distance is from a
windward-side end of one of the heat transfer tubes disposed on a
most windward side in the airflow direction to a windward-side end
of the fins, and the second distance is from a leeward-side end of
one of the heat transfer tubes disposed on a most leeward side in
the airflow direction to a leeward-side end of the fins.
8. The evaporator according to claim 6, wherein the first heat
exchange section is integral with the second heat exchange
section.
9. The evaporator according to claim 7, wherein the first heat
exchange section is integral with one or more of the second heat
exchange section and the third heat exchange section.
10. An evaporator comprising: fins disposed at a predetermined
interval in a fin thickness direction; and heat transfer tubes
extending through the fins in the fin thickness direction, wherein
each of the fins has cutouts that are in a direction orthogonal to
an airflow direction and the fin thickness direction, the heat
transfer tubes are flat multi-hole pipes inserted into the cutouts,
the evaporator comprises a first heat exchange section in which an
opening side of the cutouts is on a leeward side in the airflow
direction, and the evaporator is disposed in a refrigeration cycle
apparatus in which a non-azeotropic refrigerant mixture is
enclosed.
11. The evaporator according to claim 10, further comprising a
second heat exchange section in which the opening side of the
cutouts is disposed on a windward side in the airflow
direction.
12. The evaporator according to claim 11, wherein the first heat
exchange section is integral with the second heat exchange
section.
13. A refrigeration cycle apparatus comprising: the evaporator
according to claim 1, wherein the non-azeotropic refrigerant
mixture includes any of an HFC (hydrofluorocarbon) refrigerant, an
HFO (hydrofluoroolefin) refrigerant, CF3I (trifluoroiodomethane),
and a natural refrigerant.
14. A refrigeration cycle apparatus comprising: the evaporator
according to claim 1, wherein the non-azeotropic refrigerant
mixture includes any of R32, R1132(E), R1234yf, R1234ze, CF3I, and
CO2.
15. A refrigeration cycle apparatus comprising: the evaporator
according to claim 1, wherein the non-azeotropic refrigerant
mixture includes at least R1132(E), R32, and R1234yf.
16. A refrigeration cycle apparatus comprising: the evaporator
according to claim 1, wherein the non-azeotropic refrigerant
mixture includes at least R1132(E), R1123, and R1234yf.
17. A refrigeration cycle apparatus comprising: the evaporator
according to claim 1, wherein the non-azeotropic refrigerant
mixture includes at least R1132(E) and R1234yf.
18. A refrigeration cycle apparatus comprising: the evaporator
according to claim 1, wherein the non-azeotropic refrigerant
mixture includes at least R32, R1234yf, and at least one of R1132a
or R1114.
19. A refrigeration cycle apparatus comprising: the evaporator
according to claim 1, wherein the non-azeotropic refrigerant
mixture includes at least R32, CO2, R125, R134a, and R1234yf.
20. The refrigeration cycle apparatus comprising: the evaporator
according to claim 1, wherein the non-azeotropic refrigerant
mixture includes at least R1132(Z) and R1234yf.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to an evaporator of a
refrigeration cycle apparatus in which a non-azeotropic refrigerant
mixture is enclosed.
BACKGROUND
[0002] As an evaporator of a refrigeration cycle apparatus, there
is an evaporator in a form in which a plurality of heat transfer
tubes are unevenly distributed more on either one of the windward
side and the leeward side of the center of a heat transfer fin. For
example, the evaporator described in PTL 1 (WO2017/183180) is a
stack-type heat exchanger in which elongated holes each having a
longitudinal diameter extending in the width direction of a fin are
provided at a predetermined interval in a direction orthogonal to
the width direction and the thickness direction of the fin and in
which a flat pipe is inserted into each of the elongated holes.
SUMMARY
[0003] An evaporator according to one or more embodiments is an
evaporator of a refrigeration cycle apparatus in which a
non-azeotropic refrigerant mixture is enclosed, the evaporator
including a plurality of fins and a plurality of heat transfer
tubes. The plurality of fins are arranged at a predetermined
interval in a plate thickness direction (a fin direction). The
plurality of heat transfer tubes extend through the plurality of
fins in the plate thickness direction. In the evaporator, a first
heat exchange section is formed. In the first heat exchange
section, when the plurality of heat transfer tubes are viewed as a
heat-transfer-tube group in the plate thickness direction of the
fins, a distribution center of the heat-transfer-tube group in an
airflow direction is positioned on the leeward side of the center
of the fins in the airflow direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a schematic diagram of an air conditioning
apparatus as a refrigeration apparatus according to one or more
embodiments of the present disclosure.
[0005] FIG. 2 is a schematic front view of an indoor heat
exchanger.
[0006] FIG. 3 is an external perspective view of an outdoor heat
exchanger.
[0007] FIG. 4 is a P-H diagram of a non-azeotropic refrigerant
mixture.
[0008] FIG. 5A is a perspective view of a first heat exchange
section of an outdoor heat exchanger according to first
embodiments.
[0009] FIG. 5B is a perspective view of a second heat exchange
section of the outdoor heat exchanger according to the first
embodiments.
[0010] FIG. 6A is a schematic perspective view of an outdoor heat
exchanger that uses both the first heat exchange section and the
second heat exchange section.
[0011] FIG. 6B is a schematic perspective view of a different
outdoor heat exchanger that uses both the first heat exchange
section and the second heat exchange section.
[0012] FIG. 7A is a perspective view of a first heat exchange
section of an outdoor heat exchanger according to second
embodiments.
[0013] FIG. 7B is a perspective view of a second heat exchange
section of the outdoor heat exchanger according to the second
embodiments.
[0014] FIG. 7C is a perspective view of a third heat exchange
section of an outdoor heat exchanger according to a modification of
the second embodiments.
[0015] FIG. 8A is a perspective view of a first heat exchange
section of an outdoor heat exchanger according to third
embodiments.
[0016] FIG. 8B is a perspective view of a second heat exchange
section of the outdoor heat exchanger according to the third
embodiments.
[0017] FIG. 8C is a perspective view of a third heat exchange
section of an outdoor heat exchanger according to a modification of
the third embodiments.
DETAILED DESCRIPTION
First Embodiments
[0018] (1) Configuration of Air Conditioning Apparatus 1
[0019] FIG. 1 is a schematic diagram of an air conditioning
apparatus 1 according to one or more embodiments of the present
disclosure. In FIG. 1, the air conditioning apparatus 1 is a
refrigeration apparatus that performs cooling operation and heating
operation by a vapor compression refrigeration cycle.
[0020] A refrigerant circuit 10 of the air conditioning apparatus 1
is constituted by an outdoor unit 2 and an indoor unit 4 that are
connected to each other via a liquid-refrigerant connection pipe 5
and a gas-refrigerant connection pipe 6.
[0021] A refrigerant enclosed in the refrigerant circuit 10 is a
non-azeotropic refrigerant mixture. The non-azeotropic refrigerant
mixture includes any of a HFC (hydrofluorocarbon) refrigerant, a
HFO (hydrofluoroolefin) refrigerant, CF3I (trifluoroiodomethane),
and a natural refrigerant.
[0022] (1-1) Indoor Unit 4
[0023] The indoor unit 4 is installed indoors and constitutes part
of the refrigerant circuit 10. The indoor unit 4 includes an indoor
heat exchanger 41, an indoor fan 42, and an indoor-side control
unit 44.
[0024] (1-1-1) Indoor Heat Exchanger 41
[0025] The indoor heat exchanger 41 functions as an evaporator for
the refrigerant during cooling operation and cools indoor air. In
addition, the indoor heat exchanger 41 functions as a radiator for
the refrigerant during heating operation and heats indoor air. The
refrigerant inlet side of the indoor heat exchanger 41 during
cooling operation is connected to the liquid-refrigerant connection
pipe 5, and the refrigerant outlet side thereof is connected to the
gas-refrigerant connection pipe 6.
[0026] FIG. 2 is a front view of the indoor heat exchanger 41. In
FIG. 2, the indoor heat exchanger 41 is a cross-fin-type heat
exchanger. The indoor heat exchanger has a heat transfer fin 412
and a heat transfer tube 411.
[0027] The heat transfer fin 412 is a thin aluminum flat plate. The
heat transfer fin 412 has a plurality of through holes. The heat
transfer tube 411 has a straight tube 411a inserted into the
through holes of the heat transfer fin 412, and U-shaped tubes 411b
and 411c that couple end portions of mutually adjacent straight
tubes 411a to each other.
[0028] The straight tube 411a is in close contact with the heat
transfer fin 412 by being subjected to tube expansion processing
after inserted into the through holes of the heat transfer fin 412.
The straight tube 411a and the first U-shaped tube 411b are formed
integrally with each other. The second U-shaped tube 411c is
coupled to an end portion of the straight tube 411a by welding,
brazing, or the like after the straight tube 411a is inserted into
the through holes of the heat transfer fin 412 and subjected to
tube expansion processing.
[0029] (1-1-2) Indoor Fan 42
[0030] The indoor fan 42 takes indoor air into the indoor unit 4,
causes the indoor air to exchange heat with the refrigerant in the
indoor heat exchanger 41, and then supplies the air to the inside
of a room. As the indoor fan 42, a centrifugal fan, a multi-blade
fan, or the like is employed. The indoor fan 42 is driven by an
indoor fan motor 43.
[0031] (1-1-3) Indoor-Side Control Unit 44
[0032] The indoor-side control unit 44 controls operation of each
portion that constitutes the indoor unit 4. The indoor-side control
unit 44 has a microcomputer and a memory that are for controlling
the indoor unit 4.
[0033] The indoor-side control unit 44 transmits and receives a
control signal and the like to and from a remote controller (not
illustrated). In addition, the indoor-side control unit 44
transmits and receives a control signal and the like to and from an
outdoor-side control unit 38 of the outdoor unit 2 via a
transmission line 8a.
[0034] (1-2) Outdoor Unit 2
[0035] The outdoor unit 2 is installed outdoors and constitutes
part of the refrigerant circuit 10. The outdoor unit 2 includes a
compressor 21, a four-way switching valve 22, an outdoor heat
exchanger 23, an expansion valve 26, a liquid-side shutoff valve
27, and a gas-side shutoff valve 28.
[0036] (1-2-1) Compressor 21
[0037] The compressor 21 is a device that compresses a low-pressure
refrigerant of the refrigeration cycle. The compressor 21 drives
and rotates a positive-displacement compression element (not
illustrated) of a rotary type, a scroll type, or the like by a
compressor motor 21a.
[0038] A suction pipe 31 is connected to the suction side of the
compressor 21, and a discharge pipe 32 is connected to the
discharge side thereof. The suction pipe 31 is a refrigerant pipe
that connects the suction side of the compressor 21 and the
four-way switching valve 22 to each other. The discharge pipe 32 is
a refrigerant pipe that connects the discharge side of the
compressor 21 and the four-way switching valve 22 to each
other.
[0039] An accumulator 29 is connected to the suction pipe 31. The
accumulator 29 separates a flowed-in refrigerant into a liquid
refrigerant and a gas refrigerant and causes only the gas
refrigerant to flow to the suction side of the compressor 21.
[0040] (1-2-2) Four-Way Switching Valve 22
[0041] The four-way switching valve 22 switches the direction of
the flow of the refrigerant in the refrigerant circuit 10. During
cooling operation, the four-way switching valve 22 causes the
outdoor heat exchanger 23 to function as a radiator for the
refrigerant and causes the indoor heat exchanger 41 to function as
an evaporator for the refrigerant.
[0042] During cooling operation, the four-way switching valve 22
connects the discharge pipe 32 of the compressor 21 and a first gas
refrigerant pipe 33 of the outdoor heat exchanger 23 to each other
and connects the suction pipe 31 of the compressor 21 and a second
gas refrigerant pipe 34 to each other (refer to the solid lines of
the four-way switching valve 22 in FIG. 1).
[0043] During heating operation, the four-way switching valve 22 is
switched to a heating cycle state in which the outdoor heat
exchanger 23 functions as an evaporator for the refrigerant and in
which the indoor heat exchanger 41 functions as a radiator for the
refrigerant.
[0044] During heating operation, the four-way switching valve 22
connects the discharge pipe 32 of the compressor 21 and the second
gas refrigerant pipe 34 to each other and connects the suction pipe
31 of the compressor 21 and the first gas refrigerant pipe 33 of
the outdoor heat exchanger 23 to each other (refer to the broken
lines of the four-way switching valve 22 in FIG. 1).
[0045] Here, the first gas refrigerant pipe 33 is a refrigerant
pipe that connects the four-way switching valve 22 and the
refrigerant inlet of the outdoor heat exchanger 23 during cooling
operation to each other. The second gas refrigerant pipe 34 is a
refrigerant pipe that connects the four-way switching valve 22 and
the gas-side shutoff valve 28 to each other.
[0046] (1-2-3) Outdoor Heat Exchanger 23
[0047] The outdoor heat exchanger 23 functions as a radiator for
the refrigerant during cooling operation. In addition, the outdoor
heat exchanger 23 functions as an evaporator for the refrigerant
during heating operation. One end of a liquid refrigerant pipe 35
is connected to the refrigerant outlet of the outdoor heat
exchanger 23 during cooling operation. The other end of the liquid
refrigerant pipe 35 is connected to the expansion valve 26.
[0048] The outdoor heat exchanger 23 will be described in detail in
the section "(3) Detailed Structure of Outdoor Heat Exchanger
23".
[0049] (1-2-4) Expansion Valve 26
[0050] The expansion valve 26 is an electric expansion valve.
During cooling operation, the expansion valve 26 decompresses a
high-pressure refrigerant that is sent from the outdoor heat
exchanger 23 to a low pressure. During heating operation, the
expansion valve 26 decompresses a high-pressure refrigerant that is
sent from the indoor heat exchanger 41 to a low pressure.
[0051] (1-2-5) Liquid-Side Shutoff Valve 27 and Gas-Side Shutoff
Valve 28
[0052] The liquid-side shutoff valve 27 is connected to the
liquid-refrigerant connection pipe 5. The gas-side shutoff valve 28
is connected the gas-refrigerant connection pipe 6. The liquid-side
shutoff valve 27 is positioned downstream the expansion valve 26 in
a refrigerant circulation direction during cooling operation. The
gas-side shutoff valve 28 is positioned upstream the four-way
switching valve 22 in a refrigerant circulation direction during
cooling operation.
[0053] (1-2-6) Outdoor Fan
[0054] The outdoor unit 2 includes an outdoor fan 36. The outdoor
fan 36 takes outdoor air into the outdoor unit 2, causes the
outdoor air to exchange heat with the refrigerant in the outdoor
heat exchanger 23, and then discharges the air to the outside. As
the outdoor fan 36, a propeller fan or the like is employed. The
outdoor fan 36 is driven by an outdoor-fan motor 37.
[0055] (1-2-7) Outdoor-Side Control Unit 38
[0056] The outdoor-side control unit 38 controls operation of each
portion that constitutes the outdoor unit 2. The outdoor-side
control unit 38 has a microcomputer and a memory that are for
controlling the outdoor unit 2.
[0057] The outdoor-side control unit 38 transmits and receives a
control signal and the like to and from the indoor-side control
unit 44 of the indoor unit 4 via the transmission line 8a.
[0058] (1-3) Refrigerant Connection Pipes 5 and 6
[0059] The connection pipes 5 and 6 are refrigerant pipes that are
constructed at a local site during installation of the air
conditioning apparatus 1 in an installation location at a building
or the like. As each of the connection pipes 5 and 6, a pipe having
an appropriate length and an appropriate diameter is employed in
accordance with installation conditions such as an installation
location, a combination of the outdoor unit 2 and the indoor unit
4, and the like.
[0060] (2) Basic Operation of Air Conditioning Apparatus
[0061] Next, a basic operation of the air conditioning apparatus 1
will be described with reference to FIG. 1. The air conditioning
apparatus 1 is capable of performing cooling operation and heating
operation as basic operation.
[0062] (2-1) Cooling Operation
[0063] During cooling operation, the four-way switching valve 22 is
switched to a cooling cycle state (the state indicated by the solid
lines in FIG. 1). In the refrigerant circuit 10, a low-pressure gas
refrigerant of the refrigeration cycle is sucked by the compressor
21 and discharged after compressed.
[0064] The high-pressure gas refrigerant discharged from the
compressor 21 is sent to the outdoor heat exchanger 23 via the
four-way switching valve 22.
[0065] In the outdoor heat exchanger 23 that functions as a
radiator, the high-pressure gas refrigerant sent to the outdoor
heat exchanger 23 radiates heat by exchanging heat with outdoor air
supplied from the outdoor fan 36, and becomes a high-pressure
liquid refrigerant. The high-pressure liquid refrigerant is sent to
the expansion valve 26.
[0066] The high-pressure liquid refrigerant sent to the expansion
valve 26 is decompressed to a low pressure of the refrigeration
cycle by the expansion valve 26 and becomes a low-pressure
gas-liquid two-phase refrigerant. The low-pressure gas-liquid
two-phase refrigerant decompressed in the expansion valve 26 is
sent to the indoor heat exchanger 41 via the liquid-side shutoff
valve 27 and the liquid-refrigerant connection pipe 5.
[0067] The low-pressure gas-liquid two-phase refrigerant sent to
the indoor heat exchanger 41 evaporates in the indoor heat
exchanger 41 by exchanging heat with indoor air supplied from the
indoor fan 42. Consequently, the indoor air is cooled. Then, the
cooled air is supplied to the inside of a room, thereby cooling the
inside of the room.
[0068] The low-pressure gas refrigerant that has evaporated in the
indoor heat exchanger 41 is sucked again by the compressor 21 via
the gas-refrigerant connection pipe 6, the gas-side shutoff valve
28, and the four-way switching valve 22.
[0069] (2-2) Heating Operation
[0070] During heating operation, the four-way switching valve 22 is
switched to the heating cycle state (the state indicated by the
broken lines in FIG. 1). In the refrigerant circuit 10, a
low-pressure gas refrigerant of the refrigeration cycle is sucked
by the compressor 21 and discharged after compressed.
[0071] The high-pressure gas refrigerant discharged from the
compressor 21 is sent to the indoor heat exchanger 41 via the
four-way switching valve 22, the gas-side shutoff valve 28, and the
gas-refrigerant connection pipe 6.
[0072] The high-pressure gas refrigerant sent to the indoor heat
exchanger 41 radiates heat in the indoor heat exchanger 41 by
exchanging heat with indoor air supplied from the indoor fan 42,
and becomes a high-pressure liquid refrigerant. Consequently, the
indoor air is heated. Then, the heated air is supplied to the
inside of a room, thereby heating the inside of the room.
[0073] The high-pressure liquid refrigerant that has radiated heat
in the indoor heat exchanger 41 is sent to the expansion valve 26
via the liquid-refrigerant connection pipe 5 and the liquid-side
shutoff valve 27.
[0074] The high-pressure liquid refrigerant sent to the expansion
valve 26 is decompressed to a low pressure of the refrigeration
cycle by the expansion valve 26 and becomes a low-pressure
gas-liquid two-phase refrigerant. The low-pressure gas-liquid
two-phase refrigerant decompressed in the expansion valve 26 is
sent to the outdoor heat exchanger 23.
[0075] The low-pressure gas-liquid two-phase refrigerant sent to
the outdoor heat exchanger 23 evaporates in the outdoor heat
exchanger 23 by exchanging heat with outdoor air supplied from the
outdoor fan 36, and becomes a low-pressure gas refrigerant.
[0076] The low-pressure refrigerant that has evaporated in the
outdoor heat exchanger 23 is sucked again by the compressor 21
through the four-way switching valve 22.
[0077] (3) Detailed Description of Outdoor Heat Exchanger 23
[0078] (3-1) Structure
[0079] FIG. 3 is an external perspective view of the outdoor heat
exchanger 23. In FIG. 3, the outdoor heat exchanger 23 is a
stack-type heat exchanger. The outdoor heat exchanger 23 includes a
plurality of flat pipes 231 and a plurality of heat transfer fins
232.
[0080] (3-1-1) Flat Pipes 231
[0081] Each flat pipe 231 is a multi-hole pipe. The flat pipe 231
is formed of aluminum or an aluminum alloy and has a flat portion
231a that serves as a heat transfer surface, and a plurality of
internal flow paths 231b in which the refrigerant flows.
[0082] The flat pipes 231 are arrayed in a plurality of stages to
be stacked with a gap (ventilation space) therebetween in a state
in which respective flat portions 231a are directed
upward/downward.
[0083] (3-1-2) Heat Transfer Fins 232
[0084] Each heat transfer fin 232 is a fin made of aluminum or an
aluminum alloy. The heat transfer fin 232 is disposed in a
ventilation space between the flat pipes 231 that are vertically
adjacent to each other and is in contact with the flat portions
231a of the flat pipes 231.
[0085] The heat transfer fin 232 has cutouts 232c (refer to FIG. 5A
and FIG. 5B) into which the flat pipes 231 are inserted. After the
flat pipes 231 are inserted into the cutouts 232c of the heat
transfer fins 232, the heat transfer fins 232 and the flat portions
231a of the flat pipes 231 are joined to each other by brazing or
the like.
[0086] (3-1-3) Headers 233a and 233b
[0087] The headers 233a and 233b are coupled to both ends of the
flat pipes 231 arrayed in the plurality of stages in the up-down
direction. The headers 233a and 233b have a function of supporting
the flat pipes 231, a function of guiding the refrigerant to the
internal flow paths of the flat pipes 231, and a function of
gathering the refrigerant that has flowed out from the internal
flow paths.
[0088] When the outdoor heat exchanger 23 functions as an
evaporator for the refrigerant, the refrigerant flows into the
first header 233a. The refrigerant that has flowed into the first
header 233a is distributed to the internal flow paths of the flat
pipes 231 of the stages substantially evenly and flows toward the
second header 233b. The refrigerant that flows in the internal flow
paths of the flat pipes 231 of the stages absorbs heat via the heat
transfer fins 232 from an air flow that flows in the ventilation
spaces. The refrigerant that has flowed in the internal flow paths
of the flat pipes 231 of the stages gathers at the second header
233b and flows out from the second header 233b.
[0089] When the outdoor heat exchanger 23 functions as a radiator
for the refrigerant, the refrigerant flows into the second header
233b. The refrigerant that has flowed into the second header 233b
is distributed to the internal flow paths of the flat pipes 231 of
the stages substantially evenly and flows toward the first header
233a. The refrigerant that flows in the internal flow paths of the
flat pipes 231 of the stages radiates heat via the heat transfer
fins 232 into an air flow that flows in the ventilation spaces. The
refrigerant that has flowed in the internal flow paths of the flat
pipes 231 of the stages gathers at the first header 233a and flows
out from the first header 233a.
[0090] (3-2) Suppression of Frost
[0091] FIG. 4 is a P-H diagram of a non-azeotropic refrigerant
mixture. In FIG. 4, the refrigerant temperature increases toward
the evaporator outlet. Since the composition of the non-azeotropic
refrigerant mixture is different between a liquid phase and a gas
phase, a "temperature gradient" in which an evaporation start
temperature and an evaporation end temperature in the evaporator
are different is present. Due to the temperature gradient, the
temperature at the inlet easily decreases in the evaporator, which
easily causes frost during heating operation.
[0092] FIG. 5A is a perspective view of a first heat exchange
section 23a of the outdoor heat exchanger 23 according to one or
more embodiments. In FIG. 5A, the opening side of the cutouts 232c
is positioned on the leeward side in the airflow direction in the
first heat exchange section 23a.
[0093] FIG. 5B is a perspective view of a second heat exchange
section 23b of the outdoor heat exchanger 23 according to one or
more embodiments. In FIG. 5B, the opening side of the cutouts 232c
is positioned on the windward side in the airflow direction.
[0094] Since the openings of the cutouts 232c are positioned on the
windward side in the airflow direction in the second heat exchange
section 23b illustrated in FIG. 5B, a difference between an air
temperature and a heat-exchanger surface temperature is large, and
thus has a feature of improving heat exchange performance but
easily causing frost.
[0095] Meanwhile, since the openings of the cutouts 232c are
positioned on the leeward side in the airflow direction in the
first heat exchange section 23a illustrated in FIG. 5A, a
difference between an air temperature and a heat-exchanger surface
temperature is small compared with the second heat exchange section
23b. Frost is thus suppressed.
[0096] Therefore, in one or more embodiments, the first heat
exchange section 23a is formed on the inlet side of the outdoor
heat exchanger 23 that functions as an evaporator.
[0097] (3-3) Improvement of Heat Exchange Performance
[0098] As described above, compared with the second heat exchange
section 23b, a difference between an air temperature and a
heat-exchanger surface temperature is small in the first heat
exchange section 23a. The heat exchange performance is thus
degraded. Therefore, constituting the entirety of the outdoor heat
exchanger 23 by the first heat exchange section 23a may not be
preferable for performance.
[0099] Thus, in one or more embodiments, both the first heat
exchange section 23a and the second heat exchange section 23b are
used to improve heat exchange performance while suppressing
frost.
[0100] FIG. 6A is a schematic perspective view of the outdoor heat
exchanger 23 that uses both the first heat exchange section 23a and
the second heat exchange section 23b. FIG. 6B is a schematic
perspective view of a different outdoor heat exchanger 23' that
uses both a first heat exchange section 23a' and a second heat
exchange section 23b'.
[0101] In FIG. 6A, when the outdoor heat exchanger 23 functions as
an evaporator for the refrigerant, the refrigerant that has flowed
into the first header 233a is distributed to the internal flow
paths 231b of the flat pipes 231 of the stages substantially evenly
and flows toward the second header 233b. The temperature of the
non-azeotropic refrigerant mixture at the evaporator inlet easily
decreases, which easily causes frost. Therefore, a certain section
from the first header 233a toward the second header 233b is
constituted by the first heat exchange section 23a to suppress
frost.
[0102] Meanwhile, the temperature of the non-azeotropic refrigerant
mixture increases toward the evaporator outlet. Thus, to improve
heat exchange performance, a part between the first heat exchange
section 23a and the second header 233b is constituted by the second
heat exchange section 23b.
[0103] It is possible by thus disposing the first heat exchange
section 23a on the evaporator inlet side and the second heat
exchange section 23b on the evaporator outlet side to improve heat
exchange performance while suppressing frost.
[0104] In FIG. 6B, when the outdoor heat exchanger 23' functions as
an evaporator for the refrigerant, the refrigerant that has flowed
into the lower stage of the first header 233a' is distributed to
internal flow paths 231b' of the flat pipes 231 of the stages of
the lower stage substantially evenly and flows toward the second
header 233b'.
[0105] The refrigerant that has reached the lower stage of the
second header 233b' gathers temporarily and flows into the upper
stage of the second header 233b' via a curved pipe 234. Thereafter,
the refrigerant is distributed to the internal flow paths 231b of
the flat pipes 231 of the stages of the upper stage substantially
evenly and flows toward the second header 233b'.
[0106] The temperature of the non-azeotropic refrigerant mixture at
the evaporator inlet easily decreases, which easily causes frost.
Therefore, a section from the lower stage of the first header 233a'
toward the lower stage of the second header 233b' is constituted by
the first heat exchange section 23a' to suppress frost.
[0107] Meanwhile, the temperature of the non-azeotropic refrigerant
mixture increases toward the evaporator outlet. Thus, to improve
heat exchange performance, a section from the upper stage of the
first header 233b' toward the upper stage of the first header 233a'
is constituted by the second heat exchange section 23b'.
[0108] It is possible by thus disposing the first heat exchange
section 23a' on the evaporator inlet side and the second heat
exchange section 23b' on the evaporator outlet side to improve heat
exchange performance while suppressing frost.
[0109] (4) Features
[0110] (4-1)
[0111] In the first heat exchange section 23a of the outdoor heat
exchanger 23, the opening side of the cutouts 232c of the heat
transfer fins 232 is positioned on the leeward side in the airflow
direction. By disposing the first heat exchange section 23a on the
side of the inlet for the non-azeotropic refrigerant mixture, it is
possible to improve frost proof performance (capacity of
suppressing frost) when the outdoor heat exchanger 23 functions as
an evaporator.
[0112] (4-2)
[0113] In addition, by disposing the first heat exchange section
23a on the side of the inlet for the non-azeotropic refrigerant
mixture and disposing the second heat exchange section 23b, in
which the openings of the cutouts 232c are positioned on the
windward side in the airflow direction, on the side of the outlet,
it is possible to improve heat exchange performance while
suppressing frost.
[0114] (4-3)
[0115] The first heat exchange section 23a and the second heat
exchange section 23b are integral with each other.
[0116] (5) Modification
[0117] With the first heat exchange section 23a being disposed on
the inlet side of the outdoor heat exchanger 23 that functions as
an evaporator and the second heat exchange section 23b being
disposed on the outlet side, a third heat exchange section 23c may
be disposed between the first heat exchange section 23a and the
second heat exchange section 23b.
[0118] In the third heat exchange section 23c, the distribution
center (i.e., center of distribution) of the flat pipes 231 in the
width direction coincides with the center of the heat transfer fins
232 in the airflow direction.
[0119] The technical significance of this modification is that it
is possible to try a combination of the heat exchange sections
suitable for a refrigerant temperature in the outdoor heat
exchanger 23 that functions as an evaporator. As a result, it is
possible to improve heat exchange performance while suppressing
frost.
[0120] The first heat exchange section 23a may be integral with at
least either one of the second heat exchange section 23b and the
third heat exchange section 23c.
Second Embodiments
[0121] In one or more embodiments, a stack-type heat exchanger in
which the flat pipes 231 are inserted into the cutouts 232c
provided in the heat transfer fins 232 is employed as the outdoor
heat exchanger 23.
[0122] In one or more embodiments, a stack-type heat exchanger in
which flat pipes extend through elongated holes provided in heat
transfer fins is employed as the outdoor heat exchanger 23.
[0123] (1) Suppression of Frost
[0124] FIG. 7A is a perspective view of a first heat exchange
section 123a of the outdoor heat exchanger 23 according to one or
more embodiments. In the first heat exchange section 123a in FIG.
7A, a distance from the windward-side end of a flat pipe 231M
positioned on the most windward side in the airflow direction to
the windward-side end of a heat transfer fin 232M is a first
dimension D1.
[0125] FIG. 7B is a perspective view of a second heat exchange
section 123b of the outdoor heat exchanger 23 according to
embodiments. In the second heat exchange section 123b in FIG. 7B, a
distance from the windward-side end of the flat pipe 231M
positioned on the most windward side in the airflow direction to
the windward-side end of the heat transfer fin 232M is a second
dimension D2 smaller than the first dimension D1.
[0126] Since the distance (second dimension D2) from the
windward-side end of the flat pipe 231M positioned on the most
windward side in the airflow direction to the windward-side end of
the heat transfer fin 232M in the second heat exchange section 123b
illustrated in FIG. 7B is smaller than the distance (first
dimension D1) in the first heat exchange section 123a, a difference
between an air temperature and a heat-exchanger surface temperature
is large. The second heat exchange section 123b thus has a feature
of improving heat exchange performance but easily causing
frost.
[0127] Meanwhile, since the distance from the windward-side end of
the flat pipe 231M positioned on the most windward side in the
airflow direction to the windward-side end of the heat transfer fin
232M in the first heat exchange section 123a illustrated in FIG. 7A
is larger than the distance (second dimension D2) in the second
heat exchange section 123b, a difference between an air temperature
and a heat-exchanger surface temperature is small, compared with
the second heat exchange section 123b, which suppresses frost.
[0128] Therefore, in one or more embodiments, the first heat
exchange section 123a is formed on the inlet side of the outdoor
heat exchanger 23 that functions as an evaporator.
[0129] (2) Improvement of Heat Exchange Performance
[0130] As described above, compared with the second heat exchange
section 123b, a difference between an air temperature and a
heat-exchanger surface temperature is small in the first heat
exchange section 123a. The heat exchange performance is thus
degraded. Therefore, constituting the entirety of the outdoor heat
exchanger 23 by the first heat exchange section 123a may not be
preferable for performance.
[0131] Thus, in one or more embodiments, both the first heat
exchange section 123a and the second heat exchange section 123b are
used, as in the first embodiments, to improve heat exchange
performance while suppressing frost. FIG. 6A and FIG. 6B are also
applied to the second embodiments by replacing the first heat
exchange section 23a of the first embodiments with the "first heat
exchange section 123a" and replacing the second heat exchange
section 23b of the first embodiments with the "second heat exchange
section 123b".
[0132] In FIG. 6A, when the outdoor heat exchanger 23 functions as
an evaporator for the refrigerant, the refrigerant that has flowed
into the first header 233a is distributed to the internal flow
paths of the flat pipes of the stages substantially evenly and
flows toward the second header 233b. The temperature of the
non-azeotropic refrigerant mixture at the evaporator inlet easily
decreases, which easily causes frost. Therefore, a certain section
from the first header 233a toward the second header 233b is
constituted by the first heat exchange section 123a to suppress
frost.
[0133] Meanwhile, the temperature of the non-azeotropic refrigerant
mixture increases toward the evaporator outlet. Thus, to improve
heat exchange performance, a part between the first heat exchange
section 123a and the second header 233b is constituted by the
second heat exchange section 123b.
[0134] It is possible by thus disposing the first heat exchange
section 123a on the evaporator inlet side and the second heat
exchange section 123b on the evaporator outlet side to improve heat
exchange performance while suppressing frost.
[0135] (3) Features of Second Embodiments
[0136] (3-1)
[0137] The temperature of the non-azeotropic refrigerant mixture
increases from the inlet toward the outlet of the evaporator. Thus,
a high priority on frost proof performance (capacity of suppressing
frost) on the inlet side and a high priority on heat exchange
performance on the outlet side may be put.
[0138] Therefore, it is possible to try a combination suitable for
a refrigerant temperature in the evaporator, the combination being
such that the first heat exchange section 123a is disposed on the
inlet side of the outdoor heat exchanger 23 that functions as an
evaporator and the second heat exchange section 123b is disposed on
the outlet side.
[0139] (3-2)
[0140] The first heat exchange section 123a and the second heat
exchange section 123b are integral with each other.
[0141] (4) Modification
[0142] With the first heat exchange section 123a being disposed on
the inlet side of the outdoor heat exchanger 23 that functions as
an evaporator and the second heat exchange section 123b being
disposed on the outlet side, a third heat exchange section may be
disposed between the first heat exchange section 123a and the
second heat exchange section 123b.
[0143] FIG. 7C is a perspective view of a third heat exchange
section 123c of the outdoor heat exchanger 23 according to a
modification of one or more embodiments. In the third heat exchange
section 123c in FIG. 7C, a distance (a first distance) D3 from the
windward-side end of the flat pipe 231M positioned on the most
windward side in the airflow direction to the windward-side end of
the heat transfer fin 232M and a distance (a second distance) from
the leeward-side end of the flat pipe 231M positioned on the most
leeward side in the airflow direction to the leeward-side end of
the heat transfer fin 232M are equal to each other.
[0144] The technical significance of this modification is that it
is possible to try a combination of the heat exchange sections
suitable for a refrigerant temperature in the outdoor heat
exchanger 23 that functions as an evaporator. As a result, it is
possible to improve heat exchange performance while suppressing
frost.
[0145] The first heat exchange section 123a may be integral with at
least either one of the second heat exchange section 123b and the
third heat exchange section 123c.
Third Embodiments
[0146] In the first embodiments and the second embodiments, a
stack-type heat exchanger is employed as the outdoor heat exchanger
23. In one or more embodiments, a cross-fin-type heat exchanger is
employed as the outdoor heat exchanger 23.
[0147] (1) Suppression of Frost
[0148] FIG. 8A is a perspective view of a first heat exchange
section 223a of the outdoor heat exchanger 23 according to one or
more embodiments. In the first heat exchange section 223a in FIG.
8A, when a plurality of heat transfer tubes 231N are viewed as a
heat-transfer-tube group in the plate thickness direction of a heat
transfer fin 232N, the distribution center of the
heat-transfer-tube group in the airflow direction is positioned on
the leeward side of the center of the heat transfer fin 232N in the
airflow direction.
[0149] FIG. 8B is a perspective view of a second heat exchange
section 223b of the outdoor heat exchanger 23 according to one or
more embodiments. In the second heat exchange section 223b in FIG.
8B, the distribution center of the heat-transfer-tube group in the
airflow direction is positioned on the windward side of the center
of the heat transfer fin 232N in the airflow direction.
[0150] Since the distribution center of the heat-transfer-tube
group is positioned on the windward side of the center of the heat
transfer fin 232N in the airflow direction, a distance from the
windward-side end of the heat transfer tube 231N positioned on the
most windward side in the airflow direction to the windward-side
end of the heat transfer fin 232N is smaller in the second heat
exchange section 223b illustrated in FIG. 8B than the distance in
the first heat exchange section 223a. As a result, a difference
between an air temperature and a heat-exchanger surface temperature
is large. The second heat exchange section 223b thus has a feature
of improving heat exchange performance but easily causing
frost.
[0151] Meanwhile, since the distribution center of the
heat-transfer-tube group in the airflow direction is positioned on
the leeward side of the center of the heat transfer fin 232N in the
airflow direction, a distance from the windward-side end of the
heat transfer tube 231N positioned on the most windward side in the
airflow direction to the windward-side end of the heat transfer fin
232N is larger in the first heat exchange section 223a illustrated
in FIG. 8A than the distance in the second heat exchange section
223b. As a result, compared with the second heat exchange section
223b, a difference between an air temperature and a heat-exchanger
surface temperature is small, which suppresses frost.
[0152] Therefore, in one or more embodiments, the first heat
exchange section 223a is formed on the inlet side of the outdoor
heat exchanger 23 that functions as an evaporator.
[0153] (2) Improvement of Heat Exchange Performance
[0154] As described above, compared with the second heat exchange
section 223b, a difference between an air temperature and a
heat-exchanger surface temperature is small in the first heat
exchange section 223a. The heat exchange performance is thus
degraded. Therefore, constituting the entirety of the outdoor heat
exchanger 23 by the first heat exchange section 223a may not be
preferable for performance.
[0155] Thus, in one or more embodiments, both the first heat
exchange section 223a and the second heat exchange section 223b are
used, as in the first embodiments and the second embodiments, to
improve heat exchange performance while suppressing frost. FIG. 6A
and FIG. 6B are also applied to the third embodiments by replacing
the first heat exchange section 23a of the first embodiments with
the "first heat exchange section 223a" and replacing the second
heat exchange section 23b of the first embodiments with the "second
heat exchange section 223b".
[0156] In FIG. 6A, when the outdoor heat exchanger 23 functions as
an evaporator for the refrigerant, the refrigerant that has flowed
into the first header 233a is distributed to the heat transfer
tubes of the stages substantially evenly and flows toward the
second header 233b. The temperature of the non-azeotropic
refrigerant mixture at the evaporator inlet easily decreases, which
easily causes frost. Therefore, a certain section from the first
header 233a toward the second header 233b is constituted by the
first heat exchange section 223a to suppress frost.
[0157] Meanwhile, the temperature of the non-azeotropic refrigerant
mixture increases toward the evaporator outlet. Thus, to improve
heat exchange performance, a part between the first heat exchange
section 223a and the second header 233b is constituted by the
second heat exchange section 223b.
[0158] It is possible by thus disposing the first heat exchange
section 223a on the evaporator inlet side and the second heat
exchange section 223b on the evaporator outlet side to improve heat
exchange performance while suppressing frost.
[0159] (3) Features of Third Embodiments
[0160] (3-1)
[0161] The temperature of the non-azeotropic refrigerant mixture
increases from the inlet toward the outlet of the evaporator. Thus,
a high priority on frost proof performance (capacity of suppressing
frost) on the inlet side and a high priority on heat exchange
performance on the outlet side may be put.
[0162] Therefore, it is possible to try a combination suitable for
a refrigerant temperature in the evaporator, the combination being
such that the first heat exchange section 223a is disposed on the
inlet side of the outdoor heat exchanger 23 that functions as an
evaporator and the second heat exchange section 223b is disposed on
the outlet side.
[0163] (3-2)
[0164] The first heat exchange section 223a and the second heat
exchange section 223b are integral with each other.
[0165] (4) Modification
[0166] With the first heat exchange section 223a being disposed on
the inlet side of the outdoor heat exchanger 23 that functions as
an evaporator and the second heat exchange section 223b being
disposed on the outlet side, a third heat exchange section may be
disposed between the first heat exchange section 223a and the
second heat exchange section 223b.
[0167] FIG. 8C is a perspective view of a third heat exchange
section 223c of the outdoor heat exchanger 23 according to a
modification of one or more embodiments. In the third heat exchange
section 223c in FIG. 8C, the distribution center of the
heat-transfer-tube group in the airflow direction coincides with
the center of the fin in the airflow direction.
[0168] The technical significance of this modification is that it
is possible to try a combination of the heat exchange sections
suitable for a refrigerant temperature in the outdoor heat
exchanger 23 that functions as an evaporator. As a result, it is
possible to improve heat exchange performance while suppressing
frost.
[0169] The first heat exchange section 223a may be integral with at
least either one of the second heat exchange section 223b and the
third heat exchange section 223c.
[0170] <Others>
[0171] In each of the embodiments described above, the
non-azeotropic refrigerant mixture is described to include any of a
HFC refrigerant, a HFO refrigerant, CF3I, and a natural
refrigerant. More specifically, a non-azeotropic refrigerant
mixture corresponding to any of (A) to (G) below may be used.
[0172] (A)
[0173] A non-azeotropic refrigerant mixture that includes any of
R32, R1132(E), R1234yf, R1234ze, CF3I, and CO2
[0174] (B)
[0175] A non-azeotropic refrigerant mixture that includes at least
R1132(E), R32, and R1234yf
[0176] (C)
[0177] A non-azeotropic refrigerant mixture that includes at least
R1132(E), R1123, and R1234yf
[0178] (D)
[0179] A non-azeotropic refrigerant mixture that includes at least
R1132(E) and R1234yf
[0180] (E)
[0181] A non-azeotropic refrigerant mixture that includes at least
R32, R1234yf, and at least one of R1132a and R1114
[0182] (F)
[0183] A non-azeotropic refrigerant mixture that includes at least
R32, CO2, R125, R134a, and R1234yf
[0184] (G)
[0185] A non-azeotropic refrigerant mixture that includes at least
R1132(Z) and R1234yf
[0186] Embodiments of the present disclosure have been described
above; however, it should be understood that various changes in the
forms and details are possible without departing from the gist and
the scope of the present disclosure described in the claims.
[0187] The present disclosure is widely applicable to a
refrigeration apparatus capable of performing cooling operation and
heating operation.
[0188] Although the disclosure has been described with respect to
only a limited number of embodiments, those skilled in the art,
having benefit of this disclosure, will appreciate that various
other embodiments may be devised without departing from the scope
of the present disclosure. Accordingly, the scope of the disclosure
should be limited only by the attached claims.
REFERENCES SIGNS LIST
[0189] 1 air conditioning apparatus (refrigeration apparatus)
[0190] 23 outdoor heat exchanger (evaporator) [0191] 23a first heat
exchange section [0192] 23b second heat exchange section [0193] 23c
third heat exchange section [0194] 123a first heat exchange section
[0195] 123b second heat exchange section [0196] 123c third heat
exchange section [0197] 223a first heat exchange section [0198]
223b second heat exchange section [0199] 223c third heat exchange
section [0200] 231 flat pipe (heat transfer tube) [0201] 231M flat
pipe (heat transfer tube) [0202] 231N heat transfer tube [0203] 232
heat transfer fin [0204] 232c cutout [0205] 232M heat transfer fin
[0206] 232N heat transfer fin
PATENT LITERATURE
[0206] [0207] PTL 1 [0208] WO2017/183180
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