U.S. patent application number 14/387394 was filed with the patent office on 2015-03-19 for refrigeration device.
The applicant listed for this patent is DAIKIN INDUSTRIES, LTD.. Invention is credited to Noriyuki Okuda, Takayuki Setoguchi, Keisuke Tanimoto.
Application Number | 20150075202 14/387394 |
Document ID | / |
Family ID | 49259982 |
Filed Date | 2015-03-19 |
United States Patent
Application |
20150075202 |
Kind Code |
A1 |
Okuda; Noriyuki ; et
al. |
March 19, 2015 |
REFRIGERATION DEVICE
Abstract
A refrigeration device includes a compressor, an outdoor heat
exchanger, an expansion mechanism, an indoor heat exchanger, and a
storage tank. The compressor, the outdoor heat exchanger, the
expansion mechanism and the indoor heat exchanger are connected to
each other. During a cooling operation, a refrigerant flows
sequentially through the compressor, the outdoor heat exchanger,
the expansion mechanism, and the indoor heat exchanger. During a
heating operation, the refrigerant flows sequentially through the
compressor, the indoor heat exchanger, the expansion mechanism, and
the outdoor heat. The storage tank is configured to store the
refrigerant and is provided between the outdoor heat exchanger and
the expansion mechanism. The refrigeration device uses R32 as the
refrigerant. A capacity of the outdoor heat exchanger is less than
or equal to a capacity of the indoor heat exchanger.
Inventors: |
Okuda; Noriyuki; (Sakai-shi,
JP) ; Setoguchi; Takayuki; (Sakai-shi, JP) ;
Tanimoto; Keisuke; (Sakai-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DAIKIN INDUSTRIES, LTD. |
Osaka-shi, Osaka |
|
JP |
|
|
Family ID: |
49259982 |
Appl. No.: |
14/387394 |
Filed: |
March 26, 2013 |
PCT Filed: |
March 26, 2013 |
PCT NO: |
PCT/JP2013/058687 |
371 Date: |
September 23, 2014 |
Current U.S.
Class: |
62/324.4 |
Current CPC
Class: |
F25B 41/04 20130101;
F25B 9/002 20130101; F25B 2400/23 20130101; F25B 45/00 20130101;
F28F 2215/12 20130101; F25B 13/00 20130101; F25B 2345/002 20130101;
F25B 29/003 20130101; F28D 1/0477 20130101; F25B 1/005 20130101;
F25B 39/00 20130101; F25B 2400/13 20130101; F28D 1/05383 20130101;
F28F 1/32 20130101 |
Class at
Publication: |
62/324.4 |
International
Class: |
F25B 29/00 20060101
F25B029/00; F25B 1/00 20060101 F25B001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 28, 2012 |
JP |
2012-074661 |
Claims
1. A refrigeration device comprising: a compressor; an outdoor heat
exchanger; an expansion mechanism; an indoor heat exchanger, the
compressor, the outdoor heat exchanger, the expansion mechanism and
the indoor heat exchanger being connected to each other such that
during a cooling operation, a refrigerant flows sequentially
through the compressor, the outdoor heat exchanger, the expansion
mechanism, and the indoor heat exchanger, and during a heating
operation, the refrigerant flows sequentially through the
compressor, the indoor heat exchanger, the expansion mechanism, and
the outdoor heat; and a storage tank configured to store the
refrigerant, the storage tank being provided between the outdoor
heat exchanger and the expansion mechanism, the refrigeration
device using R32 as the refrigerant, and a capacity of the outdoor
heat exchanger being less than or equal to a capacity of the indoor
heat exchanger.
2. A refrigeration device according to claim 1, wherein the
refrigerant storage tank is configured to store refrigerant at a
high pressure in a refrigeration cycle during the cooling
operation, and the refrigerant storage tank is configured to store
refrigerant at a low pressure in a refrigeration cycle during the
heating operation.
3. A refrigeration device according to claim 1, wherein the outdoor
heat exchanger includes at least one flat tube as a heat transfer
tube.
4. A refrigeration device according to claim 3, wherein the outdoor
heat exchanger includes a plurality of flat tubes disposed at
intervals in a plurality of stacking arrangements, and fins
sandwiched by adjacent flat tubes.
5. A refrigeration device according to claim 3, wherein the outdoor
heat exchanger includes a plurality of flat tubes disposed at
intervals in a plurality of stacking arrangements, and fins
configured with notches to accommodate insertion of the flat
tubes.
6. A refrigeration device according to claim 1, wherein the outdoor
heat exchanger and the indoor heat exchanger are a cross-fin type
heat exchangers, and an outdoor heat transfer tube diameter in the
outdoor heat exchanger is smaller than an indoor heat transfer tube
diameter in the indoor heat exchanger.
7. A refrigeration device according to claim 1, further comprising
a bypass pipe arranged and configured to guide gas components in
the refrigerant, which is stored in the refrigerant storage tank,
into the compressor or a refrigerant pipe on an intake side of the
compressor.
8. A refrigeration device according to claim 7, wherein the bypass
pipe has a flow rate regulating mechanism.
9. A refrigeration device according to claim 1, wherein the
refrigerant storage tank is a gas-liquid separator.
10. A refrigeration device according to claim 2, wherein the
outdoor heat exchanger includes at least one flat tube as a heat
transfer tube.
11. A refrigeration device according to claim 2, wherein the
outdoor heat exchanger and the indoor heat exchanger are a
cross-fin type heat exchangers, and an outdoor heat transfer tube
diameter in the outdoor heat exchanger is smaller than an indoor
heat transfer tube diameter in the indoor heat exchanger.
12. A refrigeration device according to claim 2, further comprising
a bypass pipe arranged and configured to guide gas components in
the refrigerant, which is stored in the refrigerant storage tank,
into the compressor or a refrigerant pipe on an intake side of the
compressor.
13. A refrigeration device according to claim 2, wherein the
refrigerant storage tank is a gas-liquid separator.
14. A refrigeration device according to claim 3, further comprising
a bypass pipe arranged and configured to guide gas components in
the refrigerant, which is stored in the refrigerant storage tank,
into the compressor or a refrigerant pipe on an intake side of the
compressor.
15. A refrigeration device according to claim 3, wherein the
refrigerant storage tank is a gas-liquid separator.
16. A refrigeration device according to claim 6, further comprising
a bypass pipe arranged and configured to guide gas components in
the refrigerant, which is stored in the refrigerant storage tank,
into the compressor or a refrigerant pipe on an intake side of the
compressor.
17. A refrigeration device according to claim 6, wherein the
refrigerant storage tank is a gas-liquid separator.
18. A refrigeration device according to claim 7, wherein the
refrigerant storage tank is a gas-liquid separator.
Description
TECHNICAL FIELD
[0001] The present invention relates to a refrigeration device, and
in particular relates to a refrigeration device that uses R32 as a
refrigerant and is configured to enable a cooling operation and a
heating operation.
BACKGROUND ART
[0002] As disclosed in Patent Literature 1 (Japanese Patent
Application Laid-Open No. 2001-194015), a conventional
refrigeration device such as an air conditioning device that is
enabled for air cooling and air heating operations includes a
configuration that uses R32 as a refrigerant. During an air cooling
operation (cooling operation), the refrigerant in this type of
refrigeration device is configured to flow sequentially through a
gas-liquid separator (refrigerant storage tank), a compressor, an
outdoor heat exchanger, an expansion valve (expansion mechanism),
and an indoor heat exchanger. Furthermore, during an air heating
operation (heating operation), the refrigerant flows sequentially
through the refrigerant storage tank, the compressor, the indoor
heat exchanger, the expansion mechanism, and the outdoor heat
exchanger. An optimal refrigerant amount of this refrigerating
device during the cooling operation differs from an optimal
refrigerant amount during the heating operation. Consequently, a
capacity of the outdoor heat exchanger that is configured to
function as a radiator during the cooling operation is different
from a capacity of the indoor heat exchanger that is configured to
function as a radiator during the heating operation. Normally,
since the capacity of the outdoor heat exchanger is greater than
the capacity of the indoor heat exchanger, the refrigerant that
cannot be contained in the indoor heat exchanger during the heating
operation is temporarily stored in a refrigerant storage tank
connected to an intake side of the compressor.
SUMMARY OF THE INVENTION
[0003] However, since R32 is used as the refrigerant in the above
refrigeration device, under a low temperature condition, a
solubility of a refrigerating machine oil that is filled together
with the refrigerant to lubricate the compressor exhibits a
tendency to become extremely low. As a result, when operating
during a low pressure refrigeration cycle, a large fall in the
solubility of the refrigerating machine oil caused by a fall in the
refrigerant temperature results in a two layer separation of the
refrigerating machine oil and the refrigerant R32 in the
refrigerant storage tank, that is at the low pressure during the
refrigeration cycle, and thereby inhibits the return of the
refrigerating machine oil to the compressor.
[0004] Furthermore, when a high-performance radiator such as that
disclosed in Patent Literature 2 (Japanese Patent Application
Laid-Open No. 6-143991) is used as the outdoor heat exchanger in
relation to the above refrigeration device, the capacity of the
outdoor heat exchanger will be less than or equal to the capacity
of the indoor heat exchanger. Consequently, in that situation,
during the air cooling operation, the refrigerant is produced that
cannot be contained in the outdoor heat exchanger (excess
refrigerant), and the amount thereof exceeds the amount that can be
stored in the refrigerant storage tank.
[0005] Thus, in the refrigeration device configured to enable the
cooling operation and the heating operation and that uses R32 as
the refrigerant, a problem related to an oil return to the
compressor is caused by the connection of the refrigerant storage
tank to the intake side of the compressor, and when the capacity of
the outdoor heat exchanger is less than or equal to the capacity of
the indoor heat exchanger, there is also a problem of the excess
refrigerant.
[0006] The problem of the present invention is to configure the
refrigeration device, in which the capacity of the outdoor heat
exchanger is less than or equal to the capacity of the indoor heat
exchanger in the refrigeration device configured to enable the
cooling operation and the heating operation and which uses R32 as
the refrigerant, to enable the refrigerating machine oil to return
to the compressor and enable the containment of the excess
refrigerant produced during the cooling operation.
[0007] A refrigeration device according to a first aspect of the
present invention is a refrigeration device in which, during a
cooling operation, a refrigerant flows sequentially through a
compressor, an outdoor heat exchanger, an expansion mechanism, and
an indoor heat exchanger, and during a heating operation, the
refrigerant flows sequentially through the compressor, the indoor
heat exchanger, the expansion mechanism, and the outdoor heat
exchanger. Furthermore, in this refrigeration device, the
refrigerant that is used is R32, a capacity of the outdoor heat
exchanger is less than or equal to a capacity of the indoor heat
exchanger, and a refrigerant storage tank that is configured to
store the refrigerant is provided between the outdoor heat
exchanger and the expansion mechanism. A refrigeration device
according to a second aspect of the present invention is the
refrigeration device according to the first aspect of the present
invention in which the refrigerant storage tank is configured with
a high pressure in a refrigeration cycle during the cooling
operation, and a low pressure in a refrigeration cycle during the
heating operation.
[0008] Since a problem related to an oil return to the compressor
may arise as a result of use of R32 as the refrigerant in this
refrigeration device, the provision of the refrigerant storage tank
between the outdoor heat exchanger and the expansion mechanism
facilitates the return of a refrigerating machine oil to the
compressor when compared with a configuration in which the
refrigerant storage tank is provided on the intake side of the
compressor. Moreover, in light of the fact that an excess
refrigerant may be produced in this refrigeration device during the
cooling operation since the capacity of the outdoor heat exchanger
is less than or equal to the capacity of the indoor heat exchanger,
damage to a refrigerant control can be prevented since the excess
refrigerant can be contained in the refrigerant storage tank.
[0009] In this manner, this refrigeration device is configured to
enable the return of the refrigerating machine oil to the
compressor and to enable the excess refrigerant to be stored during
the cooling operation notwithstanding the fact that R32 is used as
the refrigerant and that the capacity of the outdoor heat exchanger
is less than or equal to the capacity of the indoor heat
exchanger.
[0010] A refrigeration device according to a third aspect of the
present invention is the refrigeration device according to the
first aspect and the second aspect of the present invention in
which the outdoor heat exchanger is a heat exchanger that uses a
flat tube as a heat transfer tube. Furthermore, a refrigeration
device according to a fourth aspect of the present invention is the
refrigeration device according to the third aspect of the present
invention in which the outdoor heat exchanger is a heat exchanger
that includes a plurality of the flat tubes that are disposed at
intervals in a plurality of stacking arrangements, and fins that
are sandwiched by the adjacent flat tubes. A refrigeration device
according to a fifth aspect of the present invention is the
refrigeration device according to the third aspect of the present
invention in which the outdoor heat exchanger is a heat exchanger
that includes a plurality of the flat tubes that are disposed at
intervals in a plurality of stacking arrangements, and fins that
are configured with notches to accommodate insertion of the flat
tubes.
[0011] This refrigeration device is configured to use a flat tube
as a heat transfer tube to reduce the refrigerant amount in the
refrigeration device since the capacity of the outdoor heat
exchanger is less than or equal to the capacity of the indoor heat
exchanger. Although the excess refrigerant is produced in this
refrigeration device during the cooling operation, damage to the
refrigerant control is prevented since the excess refrigerant is
contained in the refrigerant storage tank.
[0012] A refrigeration device according to a sixth aspect of the
present invention is the refrigeration device according to the
first aspect or the second aspect of the present invention in which
the outdoor heat exchanger and the indoor heat exchanger are a
cross-fin type heat exchanger, a heat transfer tube diameter in the
outdoor heat exchanger is smaller than a heat transfer tube
diameter in the indoor heat exchanger.
[0013] In this refrigeration device, in the same manner as the
refrigeration device according to the first aspect or the second
aspect, the refrigerant amount in the refrigeration device is
reduced since the capacity of the outdoor heat exchanger is less
than or equal to the capacity of the indoor heat exchanger.
Although the excess refrigerant is produced in this refrigeration
device during the cooling operation, damage to the refrigerant
control is prevented since the excess refrigerant is contained in
the refrigerant storage tank.
[0014] A refrigeration device according to a seventh aspect of the
present invention is the refrigeration device according to any one
of the first aspect to the sixth aspect of the present invention in
which a bypass pipe is further provided to guide gas components in
the refrigerant, that is stored in the refrigerant storage tank,
into the compressor or an intake pipe of the compressor.
[0015] This refrigeration device is configured to separate the
refrigerant into liquid and gas in the refrigerant storage tank
before the intake port of the outdoor heat exchanger during the
heating operation, that is to say, when the outdoor heat exchanger
is functioning as an evaporator, and then to guide the gas
components into the bypass pipe. As a result, the gas components
that do not participate in evaporation are inhibited from flowing
into the outdoor heat exchanger, and therefore, to that extent, the
flow rate of refrigerant that flows into the outdoor heat exchanger
can be reduced, and a pressure drop in relation to the refrigerant
(that is to say, depressurization loss) in the outdoor heat
exchanger can be inhibited.
[0016] A refrigeration device according to an eighth aspect of the
present invention is the refrigeration device according to the
seventh aspect of the present invention in which the bypass pipe
has a flow rate regulating mechanism.
[0017] When an operation frequency of the compressor is high, the
refrigerant that is in a gas-liquid two-phase state returns from
the refrigerant storage tank through the bypass pipe to the
compressor or the intake pipe of the compressor, and therefore
there is a risk of intake into the compressor.
[0018] However, since the bypass pipe in this refrigeration device
is configured with the flow rate regulating mechanism, the liquid
components of the refrigerant that is the gas-liquid two-phase
state is depressurized and evaporates.
[0019] In this manner, the refrigeration device is configured to
prevent return of the liquid components to the compressor or the
intake pipe of the compressor.
[0020] Furthermore the refrigerant in this refrigeration device
firstly passes through the flow rate regulating mechanism during
the heating operation, is evaporated in the outdoor heat exchanger,
and then joins flow with the refrigerant towards the compressor or
the intake pipe of the compressor. At this time, when the flow rate
regulating mechanism is an electrically operated expansion valve,
the refrigerant state immediately prior to intake into the
compressor is regulated to a more optimal condition by controlling
the valve aperture. Moreover, since the flow rate of the
refrigerant returning to the compressor can be varied by
controlling the valve aperture of the flow rate regulating
mechanism, a circulation flow rate of the refrigerant, that is to
say, the flow rate of the refrigerant flowing in the indoor heat
exchanger, can be controlled in response to a refrigerating load on
the indoor heat exchanger side.
[0021] A refrigeration device according to a ninth aspect of the
present invention is the refrigeration device according to any one
of the first aspect to the eighth aspect of the present invention
in which the refrigerant storage tank is a gas-liquid
separator.
[0022] The refrigerant storage tank in this refrigeration device is
configured as a gas-liquid separator to have both a function of
storing the liquid components and a function of separating the
liquid components and the gas components.
[0023] In this manner, since there is no requirement in this
refrigeration device to provide a device configured with the
refrigerant storage function separately to a device configured with
the gas-liquid separating function, the device configuration can be
simplified.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a schematic view of an air conditioning apparatus
as an example of a refrigeration device according to a first aspect
of the present invention.
[0025] FIG. 2 is a schematic front view of an indoor heat
exchanger.
[0026] FIG. 3 is an external perspective view of an outdoor heat
exchanger.
[0027] FIG. 4 is a graph showing ratio of outdoor heat exchanger
capacity to indoor heat exchanger capacity, according to
capability.
[0028] FIG. 5 is a schematic view of an air conditioning apparatus
as an example of a refrigeration device according to a first
modified example.
[0029] FIG. 6 is a schematic sectional view of a refrigerant
storage tank according to a second modified example.
[0030] FIG. 7 is an external perspective view of an outdoor heat
exchanger according to a third modified example.
[0031] FIG. 8 is a vertical sectional view of an outdoor heat
exchanger according to the third modified example.
DESCRIPTION OF EMBODIMENTS
[0032] The embodiments and modified examples of a refrigeration
device according to the present invention will be described below
with reference to the figures. The specific configuration of the
refrigeration device according to the present invention is not
limited to the embodiments and the modified examples below, and
changes are possible within a scope that does not depart from the
concept of the invention.
(1) Configuration of Air Conditioning Apparatus
[0033] FIG. 1 is a schematic view of an air conditioning apparatus
1 as an example of a refrigeration device according to a first
aspect of the present invention.
[0034] The air conditioning apparatus 1 is a refrigeration device
configured for an air cooling operation, as a cooling operation,
and an air heating operation, as a heating operation, through
performance of a vapor-compression refrigeration cycle. The air
conditioning apparatus 1 is principally configured by connection of
an outdoor unit 2 with an indoor unit 4. The outdoor unit 2 and the
indoor unit 4 are connected through a liquid refrigerant
communication pipe 5 and a gas refrigerant communication pipe 6.
That is to say, the outdoor unit 2 and the indoor unit 4 of a
vapor-compression refrigerant circuit 10 of the air conditioning
apparatus 1 are connected by the refrigerant communication pipes 5
and 6. The refrigerant circuit 10 is filled with R32 that is a type
of HFC refrigerant. The refrigerant circuit 10 is also filled with
refrigerating machine oil for lubricating a compressor 21
(described below) in addition to the refrigerant. In this context,
the refrigerating machine oil includes use of an ether-based
synthetic oil that exhibits some compatibility with R32, a mineral
oil that does not exhibit compatibility to R32, an
alkylbenzene-based synthetic oil, or the like.
[0035] <Indoor Unit>
[0036] The indoor unit 4 is disposed indoors, and configures a
portion of the refrigerant circuit 10. The indoor unit 4 is
principally configured by an indoor heat exchanger 41.
[0037] The indoor heat exchanger 41 cools indoor air by functioning
as an evaporator for refrigerant during an air cooling operation,
and heats indoor air by functioning as a refrigerant radiator
during an air heating operation. The liquid side of the indoor heat
exchanger 41 is connected to the liquid refrigerant communication
pipe 5 and the gas side of the indoor heat exchanger 41 is
connected to the gas refrigerant communication pipe 6.
[0038] As illustrated in FIG. 2, the indoor heat exchanger 41 is a
cross-fin type heat exchanger, and principally comprises heat
transfer fins 411 and heat transfer tubes 412. FIG. 2 is a
schematic front view of the indoor heat exchanger 41. The heat
transfer fin 411 is a thin aluminum plate, and a plurality of
through holes are provided in the heat transfer fin 411. The heat
transfer tube 412 includes a straight tube 412a configured to be
inserted into a through hole of the heat transfer fins 411, and
U-shaped tubes 412b, 412c configured to connect end portions of
adjacent straight tubes 412a. The straight tubes 412a are bonded to
the heat transfer fins 411 by tube expansion processing after
insertion into the through holes of the heat transfer fins 411. The
straight tubes 412a and the first U-shaped tubes 412b are
integrally formed, and the second U-shaped tube 412c is connected
to the end portion of the straight tube 412a by welding or
soldering after the insertion of the straight tubes 412a into the
through holes of the heat transfer fins 411 and the tube expansion
processing into the through holes of the heat transfer fins
411.
[0039] The indoor unit 4 has an indoor fan 42 that intakes indoor
air into the indoor unit 4, causes heat exchange with refrigerant
in the indoor heat exchanger 41, and then supplies air into the
room as supply air. A multiblade fan or a centrifugal fan driven by
an indoor fan motor 43, or the like, can be used as the indoor fan
42.
[0040] The indoor unit 4 has an indoor control unit 44 that
controls the operation of the respective units that configure the
indoor unit 4. The indoor control unit 44 includes a
microprocessor, a memory, or the like to perform control of the
indoor unit 4, exchanges control signals or the like with a remote
controller (not illustrated), and exchanges control signals or the
like through a transmission wire 8a with the outdoor unit 2.
[0041] <Outdoor Unit>
[0042] The outdoor unit 2 is installed in an outdoor position, and
configures a portion of the refrigerant circuit 10. The outdoor
unit 2 principally includes a compressor 21, a switching mechanism
22, an outdoor heat exchanger 23, an expansion mechanism 24, a
refrigerant storage tank 25, a liquid-side shutoff valve 27, and a
gas-side shutoff valve 28.
[0043] The compressor 21 is a device that compresses the
refrigerant that has a low pressure in the refrigeration cycle to a
high pressure. The compressor 21 has a sealed structure configured
to use a compressor motor 21a controlled by an inverter to rotate
and drive the positive-displacement compressor elements (not
illustrated) such as a rotary type or scroll type, or the like. The
compressor 21 has an intake pipe 31 connected on the intake side,
and discharge pipe 32 connected on the discharge side. The intake
pipe 31 is a refrigerant pipe that connects a first port 22a of the
switching mechanism 22 with the intake side of the compressor 21.
The intake pipe 31 includes an accumulator 29. The discharge pipe
32 is a refrigerant pipe that connects a second port 22b of the
switching mechanism 22 with the discharge side of the compressor
21.
[0044] The switching mechanism 22 is a mechanism for switching the
direction of flow of the refrigerant in the refrigerant circuit 10.
During an air cooling operation, the switching mechanism 22
switches between a function of causing the outdoor heat exchanger
23 to function as a radiator for refrigerant compressed in the
compressor 21, and causing the indoor heat exchanger 41 to function
as an evaporator for refrigerant after radiation in the outdoor
heat exchanger 23. That is to say, during an air cooling operation,
the switching mechanism 22 switches to connect the second port 22b
and the third port 22c and to connect the first port 22a and the
fourth port 22d. In this manner, the discharge side of the
compressor 21 (designated herein as the discharge pipe 32) and the
gas side of the outdoor heat exchanger 23 (designated herein as the
first gas refrigerant pipe 33) are connected (reference is made to
the solid line of the switching mechanism 22 in FIG. 1). In
addition, the intake side of the compressor 21 (designated herein
as the intake pipe 31) and the gas refrigerant communication pipe 6
side (designated herein as the second gas refrigerant pipe 34) are
connected (reference is made to the solid line of the switching
mechanism 22 in FIG. 1). Furthermore, during an air heating
operation, the switching mechanism 22 switches between a function
of causing the outdoor heat exchanger 23 to function as an
evaporator for refrigerant after radiation in the indoor heat
exchanger 41, and causing the indoor heat exchanger 41 to function
as a radiator for refrigerant compressed in the compressor 21. That
is to say, during an air heating operation, the switching mechanism
22 switches to connect the second port 22b and the fourth port 22d
and to connect the first port 22a and the third port 22c. In this
manner, the discharge side of the compressor 21 (designated herein
as the discharge pipe 32) and the gas refrigerant communication
pipe 6 side (designated herein as the second gas refrigerant pipe
34) are connected (reference is made to the broken line of the
switching mechanism 22 in FIG. 1). In addition, the intake side of
the compressor 21 (designated herein as the intake pipe 31) and the
gas side of the outdoor heat exchanger 23 (designated herein as the
first gas refrigerant pipe 33) are connected (reference is made to
the broken line of the switching mechanism 22 in FIG. 1). The first
gas refrigerant pipe 33 is a refrigerant pipe that connects the
third port 22c of the switching mechanism 22 with the gas side of
the outdoor heat exchanger 23. The second gas refrigerant pipe 34
is a refrigerant pipe that connects the fourth port 22d of the
switching mechanism 22 with the gas refrigerant communication pipe
6 side. The switching mechanism 22 as used herein is a four-way
switching valve.
[0045] The outdoor heat exchanger 23 is a heat exchanger that is
configured to function as a radiator for refrigerant that uses
outdoor air as a cooling source during an air cooling operation and
to function as an evaporator for refrigerant that uses outdoor air
as a heating source during an air heating operation. The liquid
side of the outdoor heat exchanger 23 is connected to the liquid
refrigerant pipe 35, and the gas side is connected to the first gas
refrigerant pipe 33. The liquid refrigerant pipe 35 is a
refrigerant pipe that connects the liquid side of the outdoor heat
exchanger 23 with a liquid refrigerant communication pipe 5
side.
[0046] As illustrated in FIG. 3, the outdoor heat exchanger 23 is a
heat exchanger configured to use flat tubes as heat transfer tubes.
More specifically, the outdoor heat exchanger 23 is a stacked heat
exchanger, and principally comprises flat tubes 231, waveform fins
232, and headers 233a, 233b. In this context, FIG. 3 is an external
perspective view of the outdoor heat exchanger 23. The flat tube
231 is formed from aluminum or an aluminum alloy, and comprises a
plane section 231a forming a heat transfer surface and a plurality
of internal flow passages (not illustrated) configured to allow
flow of refrigerant. The flat tubes 231 are arranged at a plurality
of levels to be stacked with gaps (ventilation spaces) therebetween
in a configuration in which the plane sections 231a are oriented
vertically. The waveform fin 232 is an aluminum or aluminum alloy
fin bent into a waveform. The waveform fin 232 is disposed in the
ventilation space to be sandwiched by the vertically adjacent flat
tubes 231, and valley portions and peak portions are configured to
make contact with the plane sections 231a of the flat tubes 231.
The valley portions and peak portions are bonded with the plane
sections 231a by soldering or the like. The headers 233a, 233b are
connected to both ends of the flat tubes 231 that are disposed in a
plurality of vertically oriented levels. The header 233a, 233b has
a function of supporting the flat tubes 231, a function of guiding
refrigerant into the internal flow passages of the flat tubes 231,
and a function of collecting refrigerant that is discharged from
the internal flow passages. When the outdoor heat exchanger 23
functions as a radiator for refrigerant, refrigerant that flows in
from a first exit/entrance 234 of the first header 233a is
distributed evenly into each internal flow passages of the
uppermost level of flat tubes 231, and flows towards the second
header 233b. The refrigerant that reaches the second header 233b is
distributed evenly into each internal flow passages of the second
level of flat tubes 231, and flows towards the first header 233a.
Thereafter, the refrigerant in the odd-numbered flat tubes 231
flows towards the second header 233b, and the refrigerant in the
even-numbered flat tubes 231 flows towards the first header 233a.
The refrigerant in the lowermost and even-numbered flat tubes 231
flows towards the first header 233a, collects in the first header
233a, and flows out from a second exit/entrance 235 of the first
header 233a. When the outdoor heat exchanger 23 functions as an
evaporator for refrigerant, refrigerant that flows in from the
exit/entrance 235 of the first header 233a, and in an opposite
direction to the direction during a function as a radiator for
refrigerant, after flowing through the flat tubes 231 and the
headers 233a, 233b, the refrigerant flows from the first
exit/entrance 234 of the first header 233a. Then, when the outdoor
heat exchanger 23 functions as a radiator for refrigerant,
refrigerant that flows in the flat tubes 231 radiates heat into the
air flow that flows in the ventilation space through the waveform
fins 232. When the outdoor heat exchanger 23 functions as an
evaporator for refrigerant, refrigerant that flows in the flat
tubes 231 absorbs heat from the air flow that flows in the
ventilation space through the waveform fins 232. Since the outdoor
heat exchanger 23 is configured as a stacked heat exchanger as
described above, the capacity of the outdoor heat exchanger 23 is
smaller than the capacity of the indoor heat exchanger 41. This
point will be described below with reference to the example of a
package air conditioning apparatus illustrated in FIG. 4. FIG. 4 is
a graph showing the ratio of outdoor heat exchanger capacity to
indoor heat exchanger capacity, according to capability. In FIG. 4,
.diamond. denotes a normal type of package air conditioning
apparatus (cross-fin type outdoor heat exchanger), .diamond-solid.
denotes a small diameter type of outdoor heat exchanger of a
package type air conditioning apparatus (stacked outdoor heat
exchanger), .DELTA. denotes a normal type of room air conditioning
apparatus (cross-fin type outdoor heat exchanger), and
.tangle-solidup. denotes a small diameter type of outdoor heat
exchanger of room air conditioning apparatus (stacked outdoor heat
exchanger). As shown in FIG. 4, the ratio of outdoor heat exchanger
capacity to indoor heat exchanger capacity is less than 1.0 when
only the outdoor heat exchanger is replaced with a stacked heat
exchanger having a similar heat exchange performance in contrast to
a combination in which the outdoor heat exchanger and the indoor
heat exchanger are both cross-fin type heat exchangers. This means
that the capacity of the stacked heat exchanger is not only less
than the capacity of the cross-fin type outdoor heat exchanger, but
is also less than the capacity of the cross-fin type indoor heat
exchanger 41 connected thereto. Therefore, excess refrigerant is
produced in the air conditioning apparatus 1 during an air cooling
operation. In the air conditioning apparatus 1, the excess
refrigerant is accommodated in the refrigerant storage tank 25. In
FIG. 4, when the ratio of outdoor heat exchanger capacity to indoor
heat exchanger capacity is 0.3 to 0.9, it is preferable to use the
refrigerant storage tank 25 for accommodating the excess
refrigerant, but even in cases in which the ratio of outdoor heat
exchanger capacity to indoor heat exchanger capacity is 1.0, stable
refrigerant control is made possible by using the refrigerant
storage tank 25.
[0047] The expansion mechanism 24 is a device configured to
depressurize the high-pressure refrigerant in the refrigeration
cycle during temporary storage in the refrigerant storage tank 25
to a low pressure in the refrigeration cycle during an air cooling
operation. The expansion mechanism 24 is a device configured to
depressurize the high-pressure refrigerant in the refrigeration
cycle that has radiated in the indoor heat exchanger 41 to a low
pressure in the refrigeration cycle during an air heating
operation. The expansion mechanism 24 is provided in portion nearer
to the liquid-side shutoff valve 27 of the liquid refrigerant pipe
35. As used herein, the expansion mechanism 24 is configured as an
electrically operated expansion valve.
[0048] The refrigerant storage tank 25 is disposed between the
outdoor heat exchanger 23 and the expansion mechanism 24. The
refrigerant storage tank 25 is a container that exhibits a high
pressure in the refrigeration cycle during an air cooling
operation, and can store high-pressure refrigerant in the
refrigeration cycle after radiation in the outdoor heat exchanger
23. In addition, the refrigerant storage tank 25 is a container
that exhibits a low pressure in the refrigeration cycle during an
air heating operation, and can store low-pressure refrigerant in
the refrigeration cycle after depressurization in the expansion
mechanism 24. For example, in cases in which the liquid refrigerant
quantity that can be contained in the indoor heat exchanger 41
during an air heating operation when the indoor heat exchanger 41
functions as a refrigerant radiator is 1100 cc, and the liquid
refrigerant quantity that can be contained in the outdoor heat
exchanger 23 during an air cooling operation when the outdoor heat
exchanger 23 functions as a refrigerant radiator is 800 cc, the
excess 300 cc of liquid refrigerant that cannot be contained in the
outdoor heat exchanger 23 during an air cooling operation is
temporarily contained in the refrigerant storage tank 25.
[0049] The liquid-side shutoff valve 27 and the gas-side shutoff
valve 28 are valves provided to a connecting port with the device
and distribution pipe to the outside (more specifically, the liquid
refrigerant communication pipe 5 and a gas refrigerant
communication pipe 6). A liquid-side shutoff valve 27 is provided
on the end portion of the liquid refrigerant pipe 35. A gas-side
shutoff valve 28 is provided on the end portion of the second gas
refrigerant pipe 34.
[0050] The outdoor unit 2 includes an outdoor fan 36 that intakes
outdoor air into the outdoor unit 2, causes heat exchange with the
refrigerant in the outdoor heat exchanger 23, and then discharges
the air to the outside. A propeller fan driven by an outdoor fan
motor 37, or the like, can be used as the outdoor fan 36.
[0051] The outdoor unit 2 includes an outdoor control unit 38 that
controls the operation of the respective units that configure the
outdoor unit 2. The outdoor control unit 38 includes a
microprocessor, a memory, or the like that performs control of the
outdoor unit 2, and exchanges control signals or the like through
the transmission wire 8a with the indoor control unit 43 of the
indoor unit 4. That is to say, a control unit 8 is configured to
perform overall operation control of the air conditioning apparatus
1 by the indoor control unit 44, the outdoor control unit 38 and
the transmission wire 8a that connects the control units 38,
44.
[0052] The control unit 8 is enabled to control the operation of
the respective types of the device and valves 21a, 22, 24, 37, 43,
and the like, based on the detection values of the respective
sensors or the various types of operational settings.
[0053] <Refrigerant Communication Pipe>
[0054] When the air conditioning apparatus 1 is installed in an
installation place such as a building and the like, the refrigerant
communication pipes 5, 6 are attached to the installation site, and
may have a configuration of a variety of lengths and diameters
depending on the installation condition, such as an installation
site or a combination of the outdoor unit and the indoor unit.
[0055] As described above, the outdoor unit 2, the indoor unit 4
and the refrigerant communication pipes 5, 6 are connected to
configure a refrigerant circuit 10 for the air conditioning
apparatus 1. During an air cooling operation that is a cooling
operation, the refrigerant circuit 10 is configured to perform a
refrigeration cycle by causing refrigerant to flow sequentially
through the compressor 21, the outdoor heat exchanger 23, the
refrigerant storage tank 25, the expansion mechanism 24, and the
indoor heat exchanger 41. During an air heating operation that is a
heating operation, the refrigerant circuit 10 is configured to
perform a refrigeration cycle by causing refrigerant to flow
sequentially through the compressor 21, the indoor heat exchanger
41, the expansion mechanism 24, the refrigerant storage tank 25,
and the outdoor heat exchanger 23. The air conditioning apparatus 1
is configured to enable each type of operation such as an air
cooling operation and an air heating operation by the control unit
8 that is configured from an indoor control unit 44 and an outdoor
control unit 38.
(2) Operation of Air conditioning Apparatus
[0056] The air conditioning apparatus 1 as described above is
enabled to perform an air cooling operation and an air heating
operation. The operation during an air cooling operation and an air
heating operation of the air conditioning apparatus will be
described below.
[0057] <Air Heating Operation>
[0058] During an air heating operation, the switching mechanism 22
switches to the configuration illustrated by the broken line in
FIG. 1, that is to say, causes communication between the second
port 22b and the fourth port 22d, and communication between the
first port 22a and the third port 22c.
[0059] The low pressure refrigerant in the refrigeration cycle in
the refrigerant circuit 10 is taken up by the compressor 21 and
discharged after compression to a high pressure in the
refrigeration cycle.
[0060] The high pressure refrigerant discharged from the compressor
21 is conveyed through the switching mechanism 22, the gas-side
shutoff valve 28 and the gas refrigerant communication pipe 6 to
the indoor heat exchanger 41.
[0061] The high pressure refrigerant conveyed to the indoor heat
exchanger 41 radiates heat by performing heat exchange with the
indoor air in the indoor heat exchanger 41. In this manner, the
indoor air is heated. In this context, since the capacity of the
indoor heat exchanger 41 is larger than the capacity of the outdoor
heat exchanger 23, during an air heating operation, almost all the
liquid refrigerant is contained in the indoor heat exchanger
41.
[0062] The high pressure refrigerant that radiates heat in the
indoor heat exchanger 41 is conveyed through the liquid refrigerant
communication pipe 5 and the liquid-side shutoff valve 27 to the
expansion mechanism 24.
[0063] The refrigerant that is conveyed to the expansion mechanism
24 is depressurized to a low pressure in the refrigeration cycle by
the expansion mechanism 24, and then is conveyed to the refrigerant
storage tank 25 and stored in the refrigerant storage tank 25. Then
the refrigerant in the refrigerant storage tank 25 is conveyed to
the outdoor heat exchanger 23.
[0064] The low pressure refrigerant conveyed to the outdoor heat
exchanger 23 undergoes evaporation by performing heat exchange with
the outdoor air supplied by the outdoor fan 36 in the outdoor heat
exchanger 23.
[0065] The low pressure refrigerant evaporated in the outdoor heat
exchanger 23 is taken up through the switching mechanism 22 again
into the compressor 21.
[0066] <Air Cooling Operation>
[0067] During air cooling operation, the switching mechanism 22
switches to the configuration illustrated by the solid line in FIG.
1, that is to say, causes communication between the second port 22b
and the third port 22c, and communication between the first port
22a and the fourth port 22d.
[0068] The low pressure refrigerant in the refrigeration cycle in
the refrigerant circuit 10 is taken up by the compressor 21 and
discharged after compression to a high pressure in the
refrigeration cycle.
[0069] The high pressure refrigerant discharged from the compressor
21 is conveyed through the switching mechanism 22 to the outdoor
heat exchanger 23.
[0070] The high pressure refrigerant conveyed to the outdoor heat
exchanger 23 radiates heat by performing heat exchange with the
outdoor air in the outdoor heat exchanger 23.
[0071] The high pressure refrigerant that radiates heat in the
outdoor heat exchanger 23 is conveyed to the refrigerant storage
tank 25. Since the capacity of the outdoor heat exchanger 23 is
less than or equal to the capacity of the indoor heat exchanger 41,
the outdoor heat exchanger 23 cannot contain all the liquid
refrigerant during the air cooling operation. Consequently, the
liquid refrigerant that cannot be contained by the outdoor heat
exchanger 23 is stored in the refrigerant storage tank 25, and the
refrigerant storage tank 25 is filled with high pressure liquid
refrigerant during the refrigeration cycle. The liquid refrigerant
in the refrigerant storage tank 25 is depressurized to a low
pressure in the refrigeration cycle by the expansion mechanism 24,
and then is conveyed through the liquid-side shutoff valve 27 and
the liquid refrigerant communication pipe 5 to the indoor heat
exchanger 41.
[0072] The low pressure refrigerant conveyed to the indoor heat
exchanger 41 undergoes evaporation by performing heat exchange with
the indoor air in the indoor heat exchanger 41. In this manner, the
indoor air is cooled.
[0073] The low pressure refrigerant evaporated in the indoor heat
exchanger 41 is taken up through the gas refrigerant communication
pipe 6, the gas-side shutoff valve 28 and the switching mechanism
22 again into the compressor 21.
(3) Characteristics of Air Conditioning Apparatus
[0074] The air conditioning apparatus 1 according to the present
embodiment has the following characteristics.
[0075] The air conditioning apparatus 1 as described above uses R32
as a refrigerant. As a result, a problem related to oil return to
the compressor 21 must be considered. Furthermore, as described
above, in the air conditioning apparatus 1, the indoor heat
exchanger 41 is configured as a cross-fin type heat exchanger, the
outdoor heat exchanger 23 is configured as a stacked heat exchanger
uses the flat tubes 231 as heat transfer tubes, and the capacity of
the outdoor heat exchanger 23 is less than or equal to 100% of the
capacity of the indoor heat exchanger 41. Consequently, excess
refrigerant is produced during an air cooling operation, and
therefore there is a risk of damage to refrigerant control.
[0076] In this respect, the air conditioning apparatus 1 as
described above is provided with the refrigerant storage tank 25
between the outdoor heat exchanger 23 and the expansion mechanism
24. The refrigerant storage tank 25 exhibits a high pressure in the
refrigeration cycle during air cooling operation and a low pressure
in the refrigeration cycle during air heating operation.
[0077] As a result, in the air conditioning apparatus 1, return of
refrigerating machine oil to the compressor 21 is facilitated in
comparison to a configuration in which the refrigerant storage tank
is provided on the intake side of the compressor 21, and the
problem of oil return to the compressor 21 is solved. Moreover, the
air conditioning apparatus 1 prevents damage to refrigerant control
since excess refrigerant produced during an air cooling operation
is contained in the refrigerant storage tank 25 since the capacity
of the outdoor heat exchanger 23 is less than or equal to the
capacity of the indoor heat exchanger 41.
[0078] In this manner, notwithstanding the fact that the air
conditioning apparatus 1 uses R32 as a refrigerant and that the
capacity of the outdoor heat exchanger 23 is less than or equal to
the capacity of the indoor heat exchanger 41, excess refrigerant
produced during an air cooling operation can be contained and
refrigerating machine oil can return to the compressor 21.
(4) Modified Example 1
[0079] In the above embodiment (reference is made to FIG. 1), as
illustrated in FIG. 5, a bypass pipe 30 may further be provided to
guide the gas component of the refrigerant that is stored in the
refrigerant storage tank 25 into the compressor 21 or the intake
pipe 31 of the compressor 21.
[0080] More specifically, for example, refrigerant immediately
prior to entering the refrigerant storage tank 25 during an air
heating operation contains a gas component that was produced when
passing through the expansion mechanism 24. As result, after the
refrigerant enters into the refrigerant storage tank 25, the liquid
component and the gas component become separated, the liquid
refrigerant is stored in a lower portion and the gas component is
stored in an upper portion. Then the gas refrigerant that is
separated in the refrigerant storage tank 25 flows through the
bypass pipe 30 to the intake pipe 31 of the compressor 21. The
liquid refrigerant that is separated in the refrigerant storage
tank 25 is depressurized in the expansion mechanism 24, and flows
into the outdoor heat exchanger 23. The bypass pipe 30 is provided
to connect the upper portion of the refrigerant storage tank 25 and
an intermediate section of the intake pipe 31. A flow rate
regulating mechanism 30a is provided at an intermediate section of
the bypass pipe 30. In this context, an electrically operation
expansion valve is used as the flow rate regulating mechanism 30a.
The outlet of the bypass pipe 30 is not connected to an
intermediate section of the intake pipe 31, and may be directly
connected with the compressor 21. The flow rate regulating
mechanism 30a is controlled by a control unit 8 in the same manner
as the other devices and valves 21a, 22, 24, 37, 43, or the like.
More specifically, during an air heating operation, the flow rate
regulating mechanism 30a is controlled to an open configuration,
and during an air cooling operation, the flow rate regulating
mechanism 30a is controlled to a closed configuration.
[0081] In this manner, during an air heating operation, high
pressure refrigerant that is conveyed to the expansion mechanism 24
after radiating heat in the indoor heat exchanger 41 is
depressurized to a low pressure in the refrigeration cycle by the
expansion mechanism 24, and thereafter is conveyed to the
refrigerant storage tank 25. The refrigerant immediately prior to
entering into the refrigerant storage tank 25, contains a gas
component that was produced during depressurization in the
expansion mechanism 24. However, after entering the refrigerant
storage tank 25, the liquid component and gas component are
separated, the liquid refrigerant is stored in the lower portion in
the refrigeration cycle and the low pressure gas refrigerant is
stored in an upper portion in the refrigeration cycle. At this
time, as described above, since the flow rate regulating mechanism
30a of the bypass pipe 30 is controlled to an open configuration,
the gas refrigerant in the refrigerant storage tank 25 flows
through the bypass pipe 30 towards the intake pipe 31 of the
compressor 21. The liquid refrigerant in the refrigerant storage
tank 25 is conveyed to the outdoor heat exchanger 23. The low
pressure refrigerant conveyed to the outdoor heat exchanger 23
evaporates as a result of heat exchange with the outdoor air
supplied by the outdoor fan 36 in the outdoor heat exchanger 23. At
this time, the flow rate of refrigerant that flows into the outdoor
heat exchanger 23 is reduced by the gas-liquid separation operation
in the refrigerant storage tank 25 and by the operation in which
gas refrigerant resulting from gas-liquid separation is taken up
through the bypass pipe 30 into the compressor 21. Consequently,
the flow rate of refrigerant flowing in the outdoor heat exchanger
23 is reduced, and it is possible to reduce the pressure drop to
that extent. Therefore the depressurization loss in the
refrigeration cycle can be reduced.
[0082] On the other hand, during an air cooling operation, as
described above, since the flow rate regulating mechanism 30a of
the bypass pipe 30 is controlled to a closed configuration, the
liquid refrigerant stored in the refrigerant storage tank 25 does
not flow into the bypass pipe 30. The liquid refrigerant in the
refrigerant storage tank 25 is depressurized to a low pressure in
the refrigeration cycle by the expansion mechanism 24, and then is
conveyed through the liquid-side shutoff valve 27 and the liquid
refrigerant communication pipe 5 to the indoor heat exchanger
41.
[0083] As described above, since the air conditioning apparatus 1
according to the present modified example is provided with a bypass
pipe 30 to guide the gas component of the refrigerant that is
stored in the refrigerant storage tank 25 into the compressor 21 or
the intake pipe 31 of the compressor 21, in addition to the effect
of the above embodiment, the following effect is also imparted.
[0084] (A)
[0085] In the air conditioning apparatus 1, refrigerant that is
depressurized in the expansion mechanism 24 during an air heating
operation is separated into a liquid component and a gas component
in the refrigerant storage tank 25, and thereafter the gas
component flows into the bypass pipe 30.
[0086] In this manner, the gas component that does not participate
in evaporation in the air conditioning apparatus 1 during an air
heating operation does not flow into the outdoor heat exchanger 23
that functions as a refrigerant evaporator, and to that extent, the
flow rate of refrigerant that flows through the outdoor heat
exchanger 23 that functions as a refrigerant evaporator can be
reduced, and therefore the depressurization loss in the
refrigeration cycle can be reduced.
[0087] (B)
[0088] When the operation frequency of the compressor 21 is high,
refrigerant that is a gas-liquid two-phase state returns from the
refrigerant storage tank 25 through the bypass pipe 30 to the
compressor 21 or the intake pipe 31 of the compressor 21, and
therefore there is a risk of intake into the compressor 21.
[0089] However, since the bypass pipe 30 in this air conditioning
apparatus 1 is configured with a flow rate regulating mechanism
30a, the liquid component of the refrigerant that is a gas-liquid
two-phase state is depressurized and evaporates.
[0090] In this manner, the air conditioning apparatus 1 can prevent
the liquid component from returning to the compressor 21 or the
intake pipe 31 of the compressor 21.
[0091] (C)
[0092] The refrigerant that passes through the flow rate regulating
mechanism 30a in this air conditioning apparatus 1 during an air
heating operation evaporates in the indoor heat exchanger 41 or the
outdoor heat exchanger 23, and then joins flow with refrigerant
towards the compressor 21 or the intake pipe 31 of the compressor
21. At this time, when the flow rate regulating mechanism 30a is
configured as an electrically operated expansion valve, the state
of the refrigerant immediately prior to intake into the compressor
21 is regulated to a more optimal condition by controlling the
valve aperture. Moreover, since the flow rate of refrigerant
returning to the compressor 21 can be varied by controlling the
valve aperture of the flow rate regulating mechanism 30a, the
circulation flow rate of refrigerant, that is to say, the flow rate
of refrigerant flowing in the indoor heat exchanger 41, can be
controlled in response to the refrigerating load on the indoor heat
exchanger 41 side.
(5) Modified Example 2
[0093] In the above modified example 1, although a container to
store the refrigerant is adopted as the configuration of the
refrigerant storage tank 25, there is not limitation in that
regard, and for example, as illustrated in FIG. 6, a cyclone-type
gas-liquid separator may be adopted.
[0094] The refrigerant storage tank 25 according to the modified
example primarily includes a cylindrical container 251, a first
connection pipe 252, a second connection pipe 253 and a third
connection pipe 254.
[0095] The first connection pipe 252 is connected in a tangential
direction relative to the peripheral side wall of the cylindrical
container 251, and is connected with the expansion mechanism 24 and
the inner portion of the cylindrical container 251. The second
connection pipe 253 is connected with the bottom wall of the
cylindrical container 251, and is connected with the outdoor heat
exchanger 23 and the inner portion of the cylindrical container
251. The third connection pipe 254 is connected with the upper wall
of the cylindrical container 251, and is connected with the bypass
pipe 30 and the inner portion of the cylindrical container 251.
[0096] As a result of this configuration, during an air heating
operation, the low pressure refrigerant in the refrigeration cycle
that flows through the first connection pipe 252 into the
cylindrical container 251 describes a vortex flow along the inner
peripheral surface 2511a of the peripheral side wall of the
cylindrical container 251, and at that time, the liquid refrigerant
attaches to the inner peripheral surface 251a to thereby enable
efficient separation of the liquid refrigerant and the gas
refrigerant.
[0097] The liquid refrigerant falls as a result of gravity, and is
stored in a lower section and flows out through the second
connection pipe 253 from the cylindrical container 251. On the
other hand, the gas refrigerant rises while revolving and is stored
in an upper section to thereby flow out through the third
connection pipe 254 from the cylindrical container 251.
[0098] As described above, in the present modified example, since a
cyclone-type gas-liquid separator is adopted as the refrigerant
storage tank 25, efficient liquid-gas separation is enabled.
Furthermore, there is no requirement for provision of both a
refrigerant storage container and a gas-liquid separator due to
provision of both a refrigerant storage function to store liquid
refrigerant and a function of separating the liquid component and
the gas component in the refrigerant storage tank 25 that comprises
a gas-liquid separator, and therefore, the apparatus configuration
can be simplified.
(6) Modified Example 3
[0099] In the above embodiment and modified examples 1 and 2, an
example was described of a stacked heat exchanger that includes a
plurality of the flat tubes 231 and waveform fins 232 as an example
of an outdoor heat exchanger 23 that uses the flat tubes 231 as
heat transfer tubes. In this outdoor heat exchanger 23, the
plurality of the flat tubes 231 are arranged at intervals in a
stacked configuration with the waveform fins 232 sandwiched by
adjacent flat tubes 231.
[0100] However, the outdoor heat exchanger 23 is not limited to the
above embodiment and modified examples 1 and 2, and for example, as
illustrated in FIG. 7 and FIG. 8, a stacked heat exchanger may be
configured to include a plurality of the flat tubes 231 that are
arranged with intervals in a stacked configuration and fins 236
configured with notches 236a to accommodate insertion of the flat
tubes 231.
[0101] The same effect as the above embodiment and modified
examples 1 and 2 is imparted by this configuration.
(7) Modified Example 4
[0102] In the above embodiment and modified examples 1 and 2, an
example was described of a stacked heat exchanger that includes a
plurality of the flat tubes 231 and waveform fins 232 as an example
of an outdoor heat exchanger 23 that uses the flat tubes 231 as
heat transfer tubes. In this outdoor heat exchanger 23, the
plurality of the flat tubes 231 are arranged at intervals in a
stacked configuration with the waveform fins 232 sandwiched by
adjacent flat tubes 231.
[0103] However, the outdoor heat exchanger 23 is not limited to the
above embodiment and modified examples 1 and 2, and for example, a
configuration is possible in which the flat tube is configured in a
serpentine shape, and the fins are sandwiched between adjacent
surfaces of the flat tube.
[0104] The same effect as the above embodiment and modified
examples 1 and 2 is imparted by this configuration.
(8) Modified Example 5
[0105] In the above embodiment and modified examples 1 to 4, an
example was described of a stacked heat exchanger in which the
outdoor heat exchanger 23 includes a plurality of the flat tubes
231 and the waveform fins 232 or the fins 236 with the notches
236a. However there is no limitation in this regard, and for
example, when the refrigeration device is configured to cool the
outdoor heat exchanger 23 using water during an air cooling
operation, a cross-fin type of heat exchanger including both an
outdoor heat exchanger 23 and an indoor heat exchanger 41 may be
configured so that the heat transfer tube diameter of the outdoor
heat exchanger 23 is smaller than the heat transfer tube diameter
of the indoor heat exchanger 41.
[0106] The same effect as the above embodiment and modified
examples 1 to 4 is imparted by this configuration.
INDUSTRIAL APPLICABILITY
[0107] The present invention relates to a refrigeration device that
uses R32 as a refrigerant and is configured to enable both a
cooling operation and a heating operation to thereby be of wide
applicability.
REFERENCE SIGNS LIST
[0108] 1 AIR CONDITIONING APPARATUS (REFRIGERATION DEVICE) [0109]
21 COMPRESSOR [0110] 23 OUTDOOR HEAT EXCHANGER [0111] 24 EXPANSION
MECHANISM [0112] 25 REFRIGERANT STORAGE TANK [0113] 30 BYPASS PIPE
[0114] 30a FLOW RATE REGULATION MECHANISM [0115] 41 INDOOR HEAT
EXCHANGER
CITATION LIST
Patent Literature
[0116] Patent Literature 1 [0117] Japanese Patent Application
Laid-Open No. 2001-194015
[0118] Patent Literature 2 [0119] Japanese Patent Application
Laid-Open No. 6-143991
* * * * *