U.S. patent application number 17/585776 was filed with the patent office on 2022-05-12 for refrigerant cycle apparatus.
This patent application is currently assigned to DAIKIN INDUSTRIES, LTD.. The applicant listed for this patent is DAIKIN INDUSTRIES, LTD.. Invention is credited to Arisa KAWAE, Hideki MATSUURA, Masaru TANAKA.
Application Number | 20220146163 17/585776 |
Document ID | / |
Family ID | |
Filed Date | 2022-05-12 |
United States Patent
Application |
20220146163 |
Kind Code |
A1 |
TANAKA; Masaru ; et
al. |
May 12, 2022 |
REFRIGERANT CYCLE APPARATUS
Abstract
There is provided a refrigerant cycle apparatus capable of
suppressing, even when a refrigerant containing CF.sub.3I is used,
corrosion of a component of a refrigerant circuit due to the
refrigerant containing CF.sub.3I. A refrigerant cycle apparatus
includes a refrigerant circuit in which a refrigerant containing
CF.sub.3I circulates, the refrigerant circuit including a
compressor, an expansion valve, an outdoor heat exchanger, and an
indoor heat exchanger that are connected to each other. The
refrigerant circuit includes a component to be in contact with the
refrigerant. At least a surface of the component to be in contact
with the refrigerant is formed by a corrosion resistance material
that contains at least one or more selected from a metal in which
the percentage of zinc is 10 wt % or less, a resin other than nylon
66, and carbon.
Inventors: |
TANAKA; Masaru; (Osaka-shi,
JP) ; MATSUURA; Hideki; (Osaka-shi, JP) ;
KAWAE; Arisa; (Osaka-shi, JP) |
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Applicant: |
Name |
City |
State |
Country |
Type |
DAIKIN INDUSTRIES, LTD. |
Osaka |
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JP |
|
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Assignee: |
DAIKIN INDUSTRIES, LTD.
Osaka
JP
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Appl. No.: |
17/585776 |
Filed: |
January 27, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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PCT/JP2020/029112 |
Jul 29, 2020 |
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17585776 |
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International
Class: |
F25B 47/00 20060101
F25B047/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 31, 2019 |
JP |
2019-141322 |
Claims
1. A refrigerant cycle apparatus including a refrigerant circuit in
which a refrigerant containing CF.sub.3I circulates, the
refrigerant circuit comprising a compressor, an expansion valve,
and a heat exchanger that are connected to each other, wherein the
refrigerant circuit includes a component to be in contact with the
refrigerant, and wherein at least a surface of the component to be
in contact with the refrigerant is formed by a corrosion resistance
material that contains at least one or more selected from the group
consisting of a metal in which a percentage of zinc is 10 wt % or
less, a resin other than nylon 66, and carbon.
2. The refrigerant cycle apparatus according to claim 1, wherein
the component is at least any of a balance weight included in the
compressor, a needle included in the expansion valve, a heat
transfer tube included in the heat exchanger, a refrigerant pipe,
and a flare nut that connects the refrigerant pipe, and wherein the
corrosion resistance material is a metal in which the percentage of
zinc is 10 wt % or less.
3. The refrigerant cycle apparatus according to claim 2, wherein
the component is the balance weight included in the compressor, and
wherein the corrosion resistance material is a copper alloy
containing 0.2 wt % or more and 1.0 wt % or less of tin or
aluminum, or stainless steel.
4. The refrigerant cycle apparatus according to claim 2, wherein
the component is the needle included in the expansion valve, and
wherein the corrosion resistance material is a copper alloy
containing 0.2 wt % or more and 1.0 wt % or less of tin or
aluminum, or stainless steel.
5. The refrigerant cycle apparatus according to claim 1, wherein
the component is a bearing of the compressor, and wherein the
corrosion resistance material is any of carbon, a polyimide resin,
and a polyamidimide resin.
6. The refrigerant cycle apparatus according to claim 1, wherein
the refrigerant circuit includes a four-way switching valve,
wherein the components is a valve body included in the four-way
switching valve, and wherein the corrosion resistance material is a
resin that contains at least one selected from the group consisting
of PBT, PET, PTFE, and PPS.
7. The refrigerant cycle apparatus according to claim 1, wherein an
air amount is 10 Torr or less and a moisture amount is 500 ppm or
less in an inside of the refrigerant circuit.
8. The refrigerant cycle apparatus according to claim 1, further
comprising a controller that controls the compressor such that a
temperature of a discharge refrigerant that is discharged from the
compressor becomes 100.degree. C. or less.
9. The refrigerant cycle apparatus according to claim 1, wherein an
ether oil or an ester oil is used as a refrigerating-machine
oil.
10. The refrigerant cycle apparatus according to claim 9, wherein
the refrigerating-machine oil contains at least one selected from
the group consisting of an extreme pressure agent, an acid
scavenger, and an antioxidant.
11. The refrigerant cycle apparatus according to claim 2, wherein
an air amount is 10 Torr or less and a moisture amount is 500 ppm
or less in an inside of the refrigerant circuit.
12. The refrigerant cycle apparatus according to claim 3, wherein
an air amount is 10 Torr or less and a moisture amount is 500 ppm
or less in an inside of the refrigerant circuit.
13. The refrigerant cycle apparatus according to claim 4, wherein
an air amount is 10 Torr or less and a moisture amount is 500 ppm
or less in an inside of the refrigerant circuit.
14. The refrigerant cycle apparatus according to claim 5, wherein
an air amount is 10 Torr or less and a moisture amount is 500 ppm
or less in an inside of the refrigerant circuit.
15. The refrigerant cycle apparatus according to claim 6, wherein
an air amount is 10 Torr or less and a moisture amount is 500 ppm
or less in an inside of the refrigerant circuit.
16. The refrigerant cycle apparatus according to claim 2, further
comprising a controller that controls the compressor such that a
temperature of a discharge refrigerant that is discharged from the
compressor becomes 100.degree. C. or less.
17. The refrigerant cycle apparatus according to claim 3, further
comprising a controller that controls the compressor such that a
temperature of a discharge refrigerant that is discharged from the
compressor becomes 100.degree. C. or less.
18. The refrigerant cycle apparatus according to claim 4, further
comprising a controller that controls the compressor such that a
temperature of a discharge refrigerant that is discharged from the
compressor becomes 100.degree. C. or less.
19. The refrigerant cycle apparatus according to claim 5, further
comprising a controller that controls the compressor such that a
temperature of a discharge refrigerant that is discharged from the
compressor becomes 100.degree. C. or less.
20. The refrigerant cycle apparatus according to claim 6, further
comprising a controller that controls the compressor such that a
temperature of a discharge refrigerant that is discharged from the
compressor becomes 100.degree. C. or less.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of PCT International
Application No. PCT/JP2020/029112, filed on Jul. 29, 2020, which
claims priority under 35 U.S.C. 119(a) to Patent Application No.
2019-141322, filed in Japan on Jul. 31, 2019, all of which are
hereby expressly incorporated by reference into the present
application.
TECHNICAL FIELD
[0002] The present disclosure relates to a refrigerant cycle
apparatus.
BACKGROUND ART
[0003] In consideration of environmental loads, a refrigerant
having a relatively small ozone depletion potential (ODP) and a
refrigerant having a relatively small global warming potential
(GWP) have been considered.
[0004] For example, in PTL 1 (Japanese Unexamined Patent
Application Publication No. 2017-149943), a refrigerant with which
it is possible to suppress the ozone depletion potential and the
global warming potential to be small has been considered.
DISCLOSURE
[0005] A refrigerant cycle apparatus according to a first aspect is
a refrigerant cycle apparatus including a refrigerant circuit. The
refrigerant circuit is constituted by a compressor, an expansion
valve, and a heat exchanger that are connected to each other. In
the refrigerant circuit, a refrigerant containing CF.sub.3I
circulates. The refrigerant circuit includes a component to be in
contact with the refrigerant. At least a surface of the component
to be in contact with the refrigerant is constituted by a corrosion
resistance material that contains at least one or more selected
from the group consisting of a metal in which the percentage of
zinc is 10 wt % or less, a resin other than nylon 66, and
carbon.
BRIEF DESCRIPTION OF DRAWINGS
[0006] FIG. 1 is a schematic diagram of an air conditioning
apparatus.
[0007] FIG. 2 is a schematic block diagram of an air conditioning
apparatus.
[0008] FIG. 3 is a schematic sectional diagram of a compressor.
[0009] FIG. 4 is a schematic sectional diagram of an expansion
valve.
[0010] FIG. 5 is a schematic sectional diagram of a four-way
switching valve.
[0011] FIG. 6 is a schematic diagram of an outdoor heat exchanger
and an indoor heat exchanger.
[0012] FIG. 7 is a schematic perspective diagram of a flare
connection portion.
DESCRIPTION OF EMBODIMENTS
[0013] Hereinafter, an air conditioning apparatus 1 as a
refrigeration cycle apparatus according to the present embodiment
will be described with reference to FIG. 1, which is a schematic
diagram of a refrigerant circuit, and FIG. 2, which is a schematic
control block diagram.
[0014] (1) Overview of Air Conditioning Apparatus 1
[0015] The air conditioning apparatus 1 is an apparatus that
conditions air in a target space by performing a vapor compression
refrigeration cycle.
[0016] The air conditioning apparatus 1 includes, mainly, an
outdoor unit 2, an indoor unit 3, a liquid refrigerant connection
pipe 6 and a gas refrigerant connection pipe 5 that connect the
outdoor unit 2 and the indoor unit 3 to each other, and a
controller 7 that controls the operation of the air conditioning
apparatus 1.
[0017] In the air conditioning apparatus 1, a refrigeration cycle
in which, after a refrigerant enclosed in a refrigerant circuit 10
is compressed and condenses, or releases heat, is decompressed, and
evaporates, the refrigerant is compressed again is performed. In
the present embodiment, the refrigerant circuit 10 is filled with a
refrigerant for performing a vapor compression refrigeration
cycle.
[0018] (Refrigerant)
[0019] As the refrigerant with which the refrigerant circuit 10 is
filled, a refrigerant constituted by only CF.sub.3I or a mixture
refrigerant containing CF.sub.3I is usable. As such a refrigerant,
for example, a refrigerant such as R466A or the like is usable as a
refrigerant containing R32, R125, and CF.sub.3I. Here, although not
limited, the content of CF.sub.3I in the refrigerant may be, for
example, 5 wt % or more and 70 wt % or less and is preferably 20 wt
% or more and 50 wt % or less. Here, the refrigerant containing
CF.sub.3I is preferable in that flammability is low and that the
values of both of ozone depletion potential (ODP) and global
warming potential (GWP) are easily balanced with low values.
[0020] (Refrigerating-Machine Oil)
[0021] A refrigerating-machine oil is enclosed together with the
refrigerant in the refrigerant circuit 10. The
refrigerating-machine oil used together with the refrigerant is
preferably an ether oil or an ester oil. As examples of the ether
oil, there are presented, for example, a polyvinyl ether oil, a
polyoxyalkylene oil, and the like. As examples of the ester oil,
there are presented, for example, a dibasic acid ester oil of
dibasic acid and monohydric alcohol, a polyol ester oil of polyol
and fatty acid or a complex ester oil of polyol, polybasic acid,
and monohydric alcohol (or fatty acid), a polyol carbonic acid
ester oil, and the like. One type of a refrigerating-machine oil
may be individually used, or two or more types of
refrigerating-machine oils may be combined together and used.
[0022] These refrigerating-machine oils can contain, as an additive
agent, at least one or more selected from the group consisting of
an extreme pressure agent, an acid scavenger, and an antioxidant.
These additive agents are each preferably blended at, for example,
3 wt % or less in the refrigerating-machine oil. In particular,
with regard to the acid scavenger in the refrigerating-machine oil,
it is preferable that concentration thereof be 1.0 wt % or more. By
regulating the blending amounts of the antioxidant and the acid
scavenger, it becomes easy to regulate the moisture content in a
fluid containing a refrigerant and a refrigerating-machine oil.
[0023] As examples of the extreme pressure agent, there are
presented, for example, an extreme pressure agent containing
phosphoric acid esters; extreme pressure agents based on
organosulfur compounds such as monosulfides, polysulfides,
sulfoxides, sulfones, thiosulfinates, sulfurized fats and oils,
thiocarbonates, thiophenes, thiazoles, and methanesulfonic acid
esters; extreme pressure agents based on thiophosphoric acid esters
such as thiophosphoric acid triesters; extreme pressure agents
based on esters such as higher fatty acids, hydroxyaryl fatty
acids, polyhydric alcohol esters, and acrylic acid esters; extreme
pressure agents based on organochlorine compounds such as
chlorinated hydrocarbons, e.g., chlorinated paraffin and
chlorinated carboxylic acid derivatives; extreme pressure agents
based on fluoroorganic compounds such as fluorinated aliphatic
carboxylic acids, fluorinated ethylene resins, fluorinated
alkylpolysiloxanes, and fluorinated graphites; extreme pressure
agents based on alcohols such as higher alcohols; and extreme
pressure agents based on metal compounds such as naphthenic acid
salts (e.g., lead naphthenate), fatty acid salts (e.g., lead fatty
acid), thiophosphoric acid salts (e.g., zinc
dialkyldithiophosphate), thiocarbamic acid salts, organomolybdenum
compounds, organotin compounds, organogermanium compounds, and
boric acid esters.
[0024] As the acid scavenger, epoxy compounds such as phenyl
glycidyl ether, alkyl glycidyl ether, alkylene glycol glycidyl
ether, cyclohexene oxide, .alpha.-olefin oxide, and epoxidized
soybean oil; carbodiimides; and the like are usable. Among these,
phenyl glycidyl ether, alkyl glycidyl ether, alkylene glycol
glycidyl ether, cyclohexene oxide, .alpha.-olefin oxide are
preferable from the point of view of compability. The carbon number
may be 3 or more and 30 or less and are more preferably 4 or more
and 24 or less. The total carbon number of .alpha.-olefin oxide may
be 4 or more and 50 or less and are more preferably 4 or more and
24 or less. As the acid scavenger, only one type of an acid
scavenger may be used, and a plurality of types of acid scavengers
can be used in combination.
[0025] As the antioxidant, for example, a phenol-based antioxidant
and an amine-based antioxidant are usable. Examples of the
phenol-based antioxidant include 2,6-di-tert-butyl-4-methylphenol
(DBPC), 2,6-di-tert-butyl-4-ethylphenol,
2,2'-methylenebis(4-methyl-6-tert-butylphenol),
2,4-dimethyl-6-tert-butylphenol, 2,6-di-tert-buthylphenol,
di-tert-butyl-p-cresol, bisphenol A, and the like. Examples of the
amine-based antioxidant include
N,N'-diisopropyl-p-phenylenediamine,
N,N'-di-sec-butyl-p-phenylenediamine, phenyl-a-naphthylamine,
N,N'-di-phenyl-p-phenylenediamine, and N,N-
di(2-naphthyl)-p-phenylenediamine, and the like.
[0026] The moisture content in the refrigerant circuit 10 is
preferably 500 ppm or less from the point of view of suppressing
decomposition of the refrigerant containing CF.sub.3I. The moisture
content in a case of a fluid that flows through an outlet of a heat
exchanger (an indoor heat exchanger 18 or an outdoor heat exchanger
13) that functions as a refrigerant condenser is preferably 500 ppm
or less.
[0027] The air amount in a fluid that flows in the refrigerant
circuit 10 is preferably 10 Torr or less from the point of view of
suppressing decomposition of the refrigerant containing
CF.sub.3I.
[0028] (1-1) Outdoor Unit 2
[0029] The outdoor unit 2 is connected to the indoor unit 3 via the
liquid refrigerant connection pipe 6 and the gas refrigerant
connection pipe 5 and constitutes part of the refrigerant circuit
10. The outdoor unit 2 includes, mainly, a compressor 11, a
four-way switching valve 12, an outdoor heat exchanger 13, an
expansion valve 9, a low-pressure receiver 14, an outdoor fan 15, a
liquid-side shutoff valve 17, and a gas-side shutoff valve 16.
[0030] The compressor 11 is an apparatus that compresses a
low-pressure refrigerant in the refrigeration cycle to a high
pressure. As the compressor 11, for example, a compressor in which
a compression element of a rotary type, a scroll type, or the like
is driven to rotate by a compressor motor is usable. Details of the
compressor 11 of the present embodiment will be described later.
The compressor motor is for changing capacity, and the operation
frequency of the compressor motor can be controlled by an
inverter.
[0031] The four-way switching valve 12 is switchable by switching
the connection state in the refrigerant circuit 10 between a first
connection state (refer to the solid lines in FIG. 1) in which the
suction side of the compressor 11 is connected to the gas-side
shutoff valve 16 while the discharge side of the compressor 11 is
connected to the outdoor heat exchanger 13 and a second connection
state (refer to the dotted lines in FIG. 1) in which the suction
side of the compressor 11 is connected to the outdoor heat
exchanger 13 while the discharge side of the compressor 11 is
connected to the gas-side shutoff valve 16. More specifically, the
four-way switching valve 12, for which details will be described
later, includes four connection ports including a first connection
port 51, a second connection port 52, a third connection port 53,
and a fourth connection port 54.
[0032] The outdoor heat exchanger 13 is a heat exchanger that
functions as a condenser or a radiator for a high-pressure
refrigerant in the refrigeration cycle in cooling operation and
functions as an evaporator for a low-pressure refrigerant in the
refrigeration cycle in heating operation. The outdoor heat
exchanger 13 includes a plurality of heat transfer tubes (not
illustrated) in which the refrigerant flows, and a plurality of
heat transfer fins (not illustrated) with a gap therebetween in
which air flows. The plurality of heat transfer tubes are arranged
in the up-down direction, and each heat transfer tube extends
substantially in the horizontal direction. The heat transfer tubes
are constituted by a metal in which the percentage of zinc is 10 wt
% or less and, more preferably, by a metal in which the percentage
of zinc is 5 wt % or less. As the metal, for example, there are
presented copper, a copper alloy, iron, an iron-containing alloy,
stainless steel, and the like. The plurality of heat transfer fins
extending in the up-down direction are arranged to be spaced from
each other at a predetermined interval in a direction in which the
heat transfer tubes extend. The plurality of heat transfer fins and
the plurality of heat transfer tubes are combined together such
that each heat transfer fin passes through the plurality of heat
transfer tubes.
[0033] The outdoor fan 15 generates an air flow for supplying
outdoor air to the outdoor heat exchanger 13 in the outdoor unit 2
and, after causing the outdoor air to exchange heat with the
refrigerant in the outdoor heat exchanger 13, discharging the
outdoor air to the outside of the outdoor unit 2. The outdoor fan
15 is driven to rotate by an outdoor fan motor.
[0034] The expansion valve 9 is provided between the liquid-side
end portion of the outdoor heat exchanger 13 and the liquid-side
shutoff valve 17. The expansion valve 9 is, for example, an
electronic expansion valve whose valve opening degree is adjustable
by control. Details of the expansion valve 9 will be described
later.
[0035] The low-pressure receiver 14 is provided between the suction
side of the compressor 11 and one of the connection ports of the
four-way switching valve 12 and is a refrigerant container capable
of storing, as a liquid refrigerant, a surplus refrigerant in the
refrigerant circuit 10.
[0036] The liquid-side shutoff valve 17 is a manual valve that is
disposed at a part of the outdoor unit 2 connected to the liquid
refrigerant connection pipe 6.
[0037] The gas-side shutoff valve 16 is a manual valve that is
disposed at a part of the outdoor unit 2 connected to the gas
refrigerant connection pipe 5.
[0038] The outdoor unit 2 includes an outdoor-unit control unit 71
that controls the operation of each component constituting the
outdoor unit 2. The outdoor-unit control unit 71 includes a
microcomputer including a CPU, a memory, and the like. The
outdoor-unit control unit 71 is connected to an indoor-unit control
unit 72 of each indoor unit 3 via a communication line, and
transmits and receives a control signal and the like.
[0039] The outdoor unit 2 is provided with a discharge temperature
sensor 75, a suction temperature sensor 76, an outdoor
heat-exchange temperature sensor 77, an outside-air temperature
sensor 78, and the like. Each of these sensors is electrically
connected to the outdoor-unit control unit 71 and transmits a
detection signal to the outdoor-unit control unit 71. The discharge
temperature sensor 75 detects the temperature of the refrigerant
that flows in a discharge pipe 4d connecting the discharge side of
the compressor 11 to the fourth connection port 54, which is one of
the connection ports of the four-way switching valve 12. The
suction temperature sensor 76 detects the temperature of the
refrigerant that flows in, among suction flow paths connecting the
suction side of the compressor 11 to one of the connection ports of
the four-way switching valve 12, a suction pipe 4e extending from
the low-pressure receiver 14 to the suction side of the compressor
11. The outdoor heat-exchange temperature sensor 77 detects the
temperature of the refrigerant that flows through an outlet of the
outdoor heat exchanger 13 on the liquid side, which is a side
opposite to the side where a third pipe 4c is connected. The
outside-air temperature sensor 78 detects the temperature of
outside air that has not passed through the outdoor heat exchanger
13 yet.
[0040] (1-2) Indoor Unit 3
[0041] The indoor unit 3 is installed on a wall surface, a ceiling,
or the like inside a room that is a target space. The indoor unit 3
is connected to an outdoor unit 2 via the liquid refrigerant
connection pipe 6 and the gas refrigerant connection pipe 5 and
constitutes part of the refrigerant circuit 10.
[0042] The indoor unit 3 includes the indoor heat exchanger 18 and
an indoor fan 19.
[0043] The indoor heat exchanger 18 is connected at the liquid side
to the liquid refrigerant connection pipe 6 and connected at the
gas-side end to the gas refrigerant connection pipe 5. The indoor
heat exchanger 18 is a heat exchanger that functions as an
evaporator for a low-pressure refrigerant in the refrigeration
cycle in cooling operation and functions as a condenser or a
radiator for a high-pressure refrigerant in the refrigeration cycle
in heating operation.
[0044] The indoor fan 19 generates an air flow for suctioning air
in a room that is an air-conditioning target space into the indoor
unit 3 and, after causing the air to exchange heat with the
refrigerant in the indoor heat exchanger 18, discharging the air to
the outside of the indoor unit 3. The indoor fan 19 is driven to
rotate by an indoor fan motor.
[0045] The indoor unit 3 includes the indoor-unit control unit 72
that controls the operation of each component constituting the
indoor unit 3. The indoor-unit control unit 72 includes a
microcomputer including a CPU, a memory, and the like. The
indoor-unit control unit 72 is connected to the outdoor-unit
control unit 71 via a communication line, and transmits and
receives a control signal and the like.
[0046] The indoor unit 3 is provided with an indoor liquid-side
heat-exchange temperature sensor 73, an indoor-air temperature
sensor 74, and the like. Each of these sensors is electrically
connected to the indoor-unit control unit 72 and transmits a
detection signal to the indoor-unit control unit 72. The indoor
liquid-side heat-exchange temperature sensor 73 detects the
temperature of the refrigerant that flows through an outlet of the
indoor heat exchanger 18 on the liquid side, which is a side
opposite to the side where the gas refrigerant connection pipe 5 is
connected. The indoor-air temperature sensor 74 detects the
temperature of indoor air that has not passed through the indoor
heat exchanger 18 yet.
[0047] (1-3) Controller 7
[0048] In the air conditioning apparatus 1, the outdoor-unit
control unit 71 and the indoor-unit control unit 72 are connected
to each other via a communication line and thereby constitute the
controller 7 that controls the operation of the air conditioning
apparatus 1.
[0049] The controller 7 includes, mainly, a CPU (central processing
unit) and a memory such as a ROM, a RAM, or the like. Components
included in the outdoor-unit control unit 71 and/or the indoor-unit
control unit 72 integrally function to thereby implement various
processing and control by the controller 7.
[0050] Preferably, the controller 7 controls constituents of the
refrigerant circuit 10 such that the maximum temperature of a
portion of the air conditioning apparatus 1 to be in contact with a
fluid that flows in the refrigerant circuit 10 becomes, for
example, 100.degree. C. or less. As such control, for example,
there are presented control in which the drive frequency of the
compressor 11 is controlled not to become a predetermined value or
more, control in which the temperature of the refrigerant
discharged from the compressor 11 is controlled not to become a
predetermined temperature or more, control in which the pressure of
a refrigerant discharged from the compressor 11 is controlled not
to become a predetermined pressure or more, and the like. Here, the
control in which the temperature of the refrigerant discharged from
the compressor 11 is controlled not to become a predetermined
temperature or more and the like may be implemented by decreasing
the drive frequency of the compressor 11 and/or by increasing the
valve opening degree of the expansion valve 9. Through the above
control, decomposition of the refrigerant containing CF.sub.3I is
suppressed, and, consequently, it is possible to suppress corrosion
effectively.
[0051] (1-4) Remote Controller 70
[0052] A remote controller 70 is disposed in a room that is an
air-conditioning target space or in a specific space of a building
including an air-conditioning target space and used by a user or
the like to perform monitoring of the operation control instruction
and the operation state of the air conditioning apparatus 1.
[0053] The remote controller 70 includes a reception portion 70a
such as an operation button, a touch panel, or the like for
receiving an input of information by being operated by a user or
the like, and a display 70b capable of displaying various
information. The remote controller 70 is connected to the
outdoor-unit control unit 71 and the indoor-unit control unit 72
via a communication line and capable of supplying information
received by the reception portion 70a from a user to the controller
7. Information received from the controller 7 can be output at the
display 70b.
[0054] Although not limited, information received from a user or
the like by the reception portion 70a includes various information
on an instruction for executing a cooling operating mode, an
instruction for executing a heating operating mode, an instruction
for stopping operation, specification of a set temperature, and the
like. Although not limited, information displayed on the display
70b includes information and the like indicating a current state
(cooling or heating) of the operating mode, a set temperature, and
occurrence of various abnormalities.
[0055] (2) Structure of Compressor 11
[0056] As the compressor 11, for example, a scroll compressor, such
as that illustrated in FIG. 3, is usable.
[0057] This compressor 11 includes a casing 20, a scroll
compression mechanism 21, a drive motor 24, a crankshaft 25, a
lower bearing 26, and a balance weight 30.
[0058] The casing 20 includes a substantially cylindrical cylinder
member 20a that opens at the upper and lower ends, and an upper
cover 20b and a lower cover 20c that are provided at the upper end
and the lower end of the cylinder member 20a, respectively. The
cylinder member 20a is fixed to the upper cover 20b and the lower
cover 20c airtightly by welding. In the casing 20, constituent
devices of the compressor 11 including the scroll compression
mechanism 21, the drive motor 24, the crankshaft 25, and the lower
bearing 26 are housed. An oil reservoir space So is formed in a
lower portion of the casing 20. In the oil reservoir space So, a
refrigerating-machine oil O for lubricating the scroll compression
mechanism 21 and the like is stored. At an upper portion of the
casing 20, the suction pipe 4e through which a low-pressure gas
refrigerant of the refrigeration cycle of the refrigerant circuit
10 is sucked and a gas refrigerant is supplied to the scroll
compression mechanism 21 is provided to extend through the upper
cover 20b. The lower end of the suction pipe 4e is connected to a
fixed scroll 22 of the scroll compression mechanism 21. The suction
pipe 4e is in communication with a compression chamber Sc, which
will be described later, of the scroll compression mechanism 21. At
an intermediate portion of the cylinder member 20a of the casing
20, the discharge pipe 4d through which a refrigerant to be
discharged to the outside of the casing 20 passes is provided. The
discharge pipe 4d is disposed such that an end portion of the
discharge pipe 4d in the inside of the casing 20 projects in a
high-pressure space Sh formed below a housing 27 of the scroll
compression mechanism 21. In the discharge pipe 4d, a high-pressure
refrigerant of the refrigeration cycle after compression by the
scroll compression mechanism 21 flows.
[0059] The scroll compression mechanism 21 includes, mainly, the
housing 27, the fixed scroll 22 disposed above the housing 27, and
a movable scroll 23 that forms the compression chamber Sc by being
combined with the fixed scroll 22.
[0060] The fixed scroll 22 includes a tabular fixed-side panel 22a,
a spiral fixed-side lap 22b projecting from the front surface of
the fixed-side panel 22a, and an outer edge portion 22c that
surrounds the fixed-side lap 22b. At a center portion of the
fixed-side panel 22a, a discharge port 22d having a noncircular
shape and in communication with the compression chamber Sc of the
scroll compression mechanism 21 is formed to extend through the
fixed-side panel 22a in the thickness direction. The refrigerant
compressed in the compression chamber Sc is discharged through the
discharge port 22d, passes through a refrigerant passage, which is
not illustrated, formed in the fixed scroll 22 and the housing 27,
and flows into the high-pressure space Sh.
[0061] The movable scroll 23 includes a tabular movable-side panel
23a, a spiral movable-side lap 23b projecting from the front
surface of the movable-side panel 23a, and a boss portion 23c
having a cylindrical shape and projecting from the back surface of
the movable-side panel 23a. The fixed-side lap 22b of the fixed
scroll 22 and the movable-side lap 23b of the movable scroll 23 are
combined together in a state in which the lower surface of the
fixed-side panel 22a and the upper surface of the movable-side
panel 23a face each other. The compression chamber Sc is formed
between the fixed-side lap 22b and the movable-side lap 23b that
are adjacent to each other. In response to the movable scroll 23
revolving with respect to the fixed scroll 22 as described later,
the volume of the compression chamber Sc periodically changes, and
suction, compression, and discharging of the refrigerant are
performed in the scroll compression mechanism 21. The boss portion
23c is a cylindrical part whose upper end is closed. An eccentric
portion 25b, which will be described later, of the crankshaft 25 is
inserted into a hollow portion of the boss portion 23c, and the
movable scroll 23 and the crankshaft 25 are thereby coupled to each
other. The boss portion 23c is disposed in an eccentric-portion
space 28 formed between the movable scroll 23 and the housing 27.
The eccentric-portion space 28 is in communication with the
high-pressure space Sh via an oil supply path 39, which will be
described later, of the crankshaft 25, and the like, and a high
pressure acts on the eccentric-portion space 28. The lower surface
of the movable-side panel 23a in the eccentric-portion space 28 is
pressed upwardly by this pressure toward the fixed scroll 22. Due
to this force, the movable scroll 23 comes into close contact with
the fixed scroll 22. The movable scroll 23 is supported by the
housing 27 via an oldham ring 29 disposed in an "oldham ring space
Sr". The oldham ring 29 is a member that prevents the movable
scroll 23 from rotating on its axis and causes the movable scroll
23 to revolve. By using the oldham ring 29, when the crankshaft 25
rotates, the movable scroll 23 coupled at the boss portion 23c to
the crankshaft 25 revolves with respect to the fixed scroll 22
without rotating on its axis, and the refrigerant in the
compression chamber Sc is compressed.
[0062] The housing 27 is press-fitted to the inner side of the
cylinder member 20a and fixed at the entirety of the outer
peripheral surface thereof in the circumferential direction to the
cylinder member 20a. The housing 27 and the fixed scroll 22 are
fixed to each other by a bolt or the like, which is not
illustrated, such that the upper end surface of the housing 27 is
in close contact with the lower surface of the outer edge portion
22c of the fixed scroll 22. At the housing 27, a concave portion
27a disposed to be recessed at a center portion of the upper
surface and an upper bearing portion 27b disposed below the concave
portion 27a are formed. The concave portion 27a surrounds a side
surface of the eccentric-portion space 28 in which the boss portion
23c of the movable scroll 23 is disposed. At the upper bearing
portion 27b, an upper bearing 35 that is a cylindrical metal member
pivotably supporting a main shaft 25a of the crankshaft 25 is
disposed. The upper bearing 35 rotatably supports the main shaft
25a inserted into the upper bearing 35. In addition, the oldham
ring space Sr in which the oldham ring 29 is disposed is formed in
the housing 27.
[0063] The drive motor 24 includes an annular stator 33 fixed to
the inner wall surface of the cylinder member 20a, and, on the
inner side of the stator 33, a rotor 32 that is rotatably housed
with a slight gap (air gap passage). The stator 33 is configured to
include a coil. The rotor 32 is coupled to the movable scroll 23
via the crankshaft 25 disposed to extend in the up-down direction
along the axis of the cylinder member 20a. The rotor 32 rotates and
thereby causes the movable scroll 23 to revolve with respect to the
fixed scroll 22.
[0064] The crankshaft 25 transmits the driving force of the drive
motor 24 to the movable scroll 23. The crankshaft 25 is disposed to
extend in the up-down direction along the axis of the cylinder
member 20a and couples the rotor 32 of the drive motor 24 and the
movable scroll 23 of the scroll compression mechanism 21 to each
other. The crankshaft 25 includes the main shaft 25a whose center
axis is coincident with the axis of the cylinder member 20a, and
the eccentric portion 25b eccentric to the axis of the cylinder
member 20a. The eccentric portion 25b is inserted into the boss
portion 23c of the movable scroll 23 as described above. A pin
bearing 31 that is a cylindrical metal member pivotably supporting
the eccentric portion 25b is provided on the outer side of the
eccentric portion 25b in the radial direction. The main shaft 25a
is rotatably supported by the pin bearing 31, the upper bearing 35
of the upper bearing portion 27b of the housing 27, and the lower
bearing 26, which will be described later. The main shaft 25a is
coupled between the upper bearing 35 and the lower bearing 26 to
the rotor 32 of the drive motor 24. In the inside of the crankshaft
25, the oil supply path 39 for supplying the refrigerating-machine
oil O to the scroll compression mechanism 21 and the like is
formed. The lower end of the main shaft 25a is positioned in the
oil reservoir space So formed in the lower portion of the casing
20, and the refrigerating-machine oil O of the oil reservoir space
So is supplied through the oil supply path 39 to the scroll
compression mechanism 21 and the like.
[0065] The balance weight 30 is an annular member separated from
the crankshaft 25 and is fitted to the main shaft 25a. The balance
weight 30 includes a cylindrical part 30a and an eccentric part 30b
formed at a portion of the cylindrical part 30a in the
circumferential direction. The cylindrical part 30a has a centroid
present on the axis of the crankshaft 25 and has a circular shape
as viewed in the axial direction. The centroid of the eccentric
part 30b is eccentric from the axis of the crankshaft 25 and,
specifically, is eccentric from the axis of the crankshaft 25 in a
predetermined direction. Consequently, the centroid of the entirety
of the balance weight 30 is also eccentric from the axis of the
crankshaft 25 in a predetermined direction. As described above, the
movable scroll 23 is slidably supported at a portion thereof in the
vicinity of the center by the eccentric portion 25b of the
crankshaft 25. Consequently, the movable scroll 23 is also
eccentric in the same direction as the eccentric portion 25b. With
the above structure, it is possible to balance with the movable
scroll 23 by disposing the balance weight 30 at the main shaft 25a
with the predetermined direction directed opposite to the eccentric
direction of the eccentric portion 25b. It is thus possible to
prevent rocking of the crankshaft 25.
[0066] The lower bearing 26 is disposed below the drive motor 24.
The lower bearing 26 is fixed on the inner side and below the
cylinder member 20a. The lower bearing 26 is a cylindrical metal
member that constitutes the bearing on the lower end side of the
crankshaft 25 and that supports the main shaft 25a of the
crankshaft 25 rotatably.
[0067] Next, the operation of the compressor 11 will be
described.
[0068] When the drive motor 24 is started, the rotor 32 rotates
with respect to the stator 33, and the crankshaft 25 fixed to the
rotor 32 rotates. When the crankshaft 25 rotates, the movable
scroll 23 coupled to the crankshaft 25 revolves with respect to the
fixed scroll 22. Then, a low-pressure gas refrigerant in the
refrigeration cycle is sucked into the compression chamber Sc from
the peripheral edge side of the compression chamber Sc through the
suction pipe 4e. In response to the movable scroll 23 revolving,
the suction pipe 4e and the compression chamber Sc become not in
communication with each other. Then, in response to a decrease in
the capacity of the compression chamber Sc, the pressure of the
compression chamber Sc starts to increase.
[0069] The refrigerant in the compression chamber Sc is compressed
in response to the capacity of the compression chamber Sc
decreasing and eventually becomes a high-pressure gas refrigerant.
The high-pressure gas refrigerant is discharged through the
discharge port 22d positioned near the center of the fixed-side
panel 22a. Thereafter, the high-pressure gas refrigerant passes
through a refrigerant passage, which is not illustrated, formed in
the fixed scroll 22 and the housing 27 and flows into the
high-pressure space Sh. The high-pressure gas refrigerant of the
refrigeration cycle that has flowed into the high-pressure space Sh
after compressed by the scroll compression mechanism 21 is
discharged from the discharge pipe 4d.
[0070] In the above compressor 11, in particular, at least any one
of the pin bearing 31, the upper bearing 35, the lower bearing 26,
the balance weight 30, the movable scroll 23, the fixed scroll 22,
the oldham ring 29, and the crankshaft 25 is preferably constituted
by a metal in which the percentage of zinc is 10 wt % or less and
more preferably constituted by a metal in which the percentage of
zinc is 5 wt % or less.
[0071] In particular, since the density and the specific gravity of
the balance weight 30 are large, from the point of view of
downsizing, excellent workability, and favorable suppression of
corrosion due to the refrigerant containing CF.sub.3I or a
decomposition product thereof, the balance weight 30 is preferably
constituted by a copper alloy in which the percentage of zinc is 5
wt % of less and more preferably constituted by a copper alloy in
which the percentage of zinc is 5 wt % or less and in which 0.2 wt
% or more and 1.0 wt % or less of tin or aluminum is contained.
When the balance weight 30 is constituted by a metal that differs
from a copper alloy, stainless steel such as SUS304 or the like is
preferable.
[0072] The pin bearing 31, the upper bearing 35, and the lower
bearing 26 are preferably constituted by any of carbon, a polyimide
resin, and a polyamidimide resin from the point of view of low
friction properties, low abrasion properties, excellent
workability, and favorable suppression of corrosion due to the
refrigerant containing CF.sub.3I or a decomposition product
thereof.
[0073] (3) Structure of Expansion Valve 9
[0074] As the expansion valve 9, for example, an electronic
expansion valve, such as that illustrated in FIG. 4, in which a
valve body 93 including a needle 93b is used is usable.
[0075] This expansion valve 9 includes, mainly, a coil 91, a rotor
92, the valve body 93, a casing 94, a valve sheet member 95, and
the like.
[0076] The coil 91 is provided in the circumferential direction
when the longitudinal direction of the valve body 93 is considered
as the axial direction.
[0077] The rotor 92 is driven to rotate by the coil 91. The rotor
92 moves in a screw axis direction by rotating.
[0078] The valve body 93 is constituted by a shaft 93a and the
needle 93b. The shaft 93a has a cylindrical shape and extends
vertically. One end of the shaft 93a is attached to the rotor 92 to
be coaxial therewith. The shaft 93a moves together with the rotor
92 in the axial direction. The needle 93b is provided at the lower
end of the shaft 93a to have a conical shape directed downward. The
needle 93b projects in a valve-body-side space 96, which will be
described later.
[0079] The coil 91, the rotor 92, the shaft 93a of the valve body
93, and the like are housed in the inside of the casing 94.
[0080] The valve sheet member 95 is provided below the casing 94.
The valve seat member 95 includes a first coupling portion 97, a
second coupling portion 98, a valve-body-side space 96 for causing
the first coupling portion 97 and the second coupling portion 98 to
be in communication with each other, and a valve seat 99 provided
between the valve-body-side space 96 and the first coupling portion
97. The valve seat 99 has a funnel shape to face the needle 93b of
the valve body 93 from below on the outer side in the radial
direction.
[0081] Thus, a high-pressure liquid refrigerant that has flowed in
from the first coupling portion 97 or the second coupling portion
98 is decompressed by passing through a gap between the needle 93b
and the valve seat 99. The degree of decompression at this time is
regulated by changing the size of the gap between the needle 93b
and the valve seat 99 by moving the valve body 93 forward and
rearward by the rotation of the rotor 92.
[0082] The valve body 93 including the needle 93b can be
constituted by a copper alloy in which the percentage of zinc is 10
wt % or less, is preferably constituted by a copper alloy in which
the percentage of zinc is 5 wt % or less, and is more preferably
constituted by a copper alloy in which the percentage of zinc is 5
wt % or less and in which 0.2 wt % or more and 1.0 wt % or less of
tin or aluminum is contained, from the point of view of excellent
erosion resistance, corrosion resistance and favorable suppression
of corrosion due to the refrigerant containing CF.sub.3I or a
decomposition product thereof. When the valve body 93 including the
needle 93b is constituted by a metal that differs from a copper
alloy, stainless steel such as SUS304 or the like is
preferable.
[0083] (4) Structure of Four-Way Switching Valve 12
[0084] As illustrated in FIG. 5, the four-way switching valve 12
includes a four-way switching valve body 50, a pilot
electromagnetic valve 60 for switching connection states, a
high-pressure extraction pipe 64a, a low-pressure extraction pipe
61a, a first pilot pipe 62a, and a second pilot pipe 63a. Note that
"LP" in FIG. 5 indicates the pressure of a refrigerant sucked by
the compressor 11, and "HP" indicates the pressure of the
refrigerant discharged from the compressor 11.
[0085] The four-way switching valve body 50 includes four
connection ports including the first connection port 51, the second
connection port 52, the third connection port 53, and the fourth
connection port 54, a valve body 57, a first chamber 55, a second
chamber 56, a first communication portion 55a, a second
communication portion 56a, a high-pressure extraction portion 54a,
and a low-pressure extraction portion 51a.
[0086] The discharge pipe 4d extending from the discharge side of
the compressor 11 is connected to the fourth connection port 54 of
the four-way switching valve body 50. A first pipe 4a extending
from the low-pressure receiver 14 is connected to the first
connection port 51 of the four-way switching valve body 50. A
second pipe 4b extending from the gas-side shutoff valve 16 is
connected to the second connection port 52 of the four-way
switching valve body 50. The third pipe 4c extending from the
gas-side end portion of the outdoor heat exchanger 13 is connected
to the third connection port 53 of the four-way switching valve
body 50.
[0087] In the first connection state of the four-way switching
valve body 50, the valve body 57 is positioned at a first location
so that the fourth connection port 54 and the third connection port
53 are in communication with each other while the second connection
port 52 and the first connection port 51 are in communication with
each other. Consequently, in the first connection state, the
refrigerant discharged from the discharge side of the compressor 11
flows through the discharge pipe 4d, the fourth connection port 54,
the third connection port 53, and the third pipe 4c sequentially
and is supplied to the gas-side end portion of the outdoor heat
exchanger 13. In the first connection state, the refrigerant that
has sent from the gas refrigerant connection pipe 5 via the
gas-side shutoff valve 16 to the second pipe 4b flows through the
second connection port 52, the first connection port 51, the first
pipe 4a, the low-pressure receiver 14, and the suction pipe 4e and
is sent to the suction side of the compressor 11.
[0088] In the second connection state of the four-way switching
valve 50, the valve body 57 is positioned at a second location so
that the fourth connection port 54 and the second connection port
52 are in communication with each other while the third connection
port 53 and the first connection port 51 are in communication with
each other. Consequently, in the second connection state, the
refrigerant discharged from the discharge side of the compressor 11
flows through the discharge pipe 4d, the fourth connection port 54,
the second connection port 52, and the second pipe 4b sequentially
and is sent to the gas refrigerant connection pipe 5 via the
gas-side shutoff valve 16. In the second state, the refrigerant
that has passed through the gas-side end portion of the outdoor
heat exchanger 13 flows through the third pipe 4c, the third
connection port 53, the first connection port 51, the first pipe
4a, the low-pressure receiver 14, and the suction pipe 4e
sequentially and is sent to the suction side of the compressor
11.
[0089] The valve body 57 is positioned between the first chamber 55
and the second chamber 56 in the inside of the four-way switching
valve body 50. The valve body 57 is provided to partition a space
on the side of the first connection port 51 and a space on the side
of the fourth connection port 54 from each other. The valve body 57
moves by sliding in response to a pressure that acts on the first
chamber 55 and the second chamber 56. Specifically, in a state in
which a low pressure acts on the first chamber 55 and a high
pressure acts on the second chamber 56, the valve body 57 moves by
sliding such that the first chamber 55 becomes smaller and the
second chamber 56 becomes larger, thereby making a state in which
the fourth connection port 54 and the third connection port 53 are
in communication with each other while the second connection port
52 and the first connection port 51 are in communication with each
other. In a state in which a high pressure acts on the first
chamber 55 and a low pressure acts on the second chamber 56, the
valve body 57 moves by sliding such that the first chamber 55
becomes larger and the second chamber 56 becomes smaller, thereby
making a state in which the fourth connection port 54 and the
second connection port 52 are in communication with each other
while the third connection port 53 and the first connection port 51
are in communication with each other.
[0090] The first chamber 55 is provided with the first
communication portion 55a. A first pilot pipe 62a that is a
capillary tube extending from the pilot electromagnetic valve 60 is
connected to the first communication portion 55a. Consequently, a
refrigerant pressure of the first pilot pipe 62a acts on the first
chamber 55.
[0091] The second chamber 56 is provided with the second
communication portion 56a. A second pilot pipe 63a that is a
capillary tube extending from the pilot electromagnetic valve 60 is
connected to the second communication portion 56a. Consequently, a
refrigerant pressure of the second pilot pipe 63a acts on the
second chamber 56.
[0092] The high-pressure extraction portion 54a is provided in a
space other than the first chamber 55 and the second chamber 56 of
the internal space of the four-way switching valve body 50, the
space being defined by the valve body 57 such that the fourth
connection port 54 is positioned in the space. The high-pressure
extraction pipe 64a, which is a capillary tube extending from the
pilot electromagnetic valve 60, is connected to the high-pressure
extraction portion 54a. Consequently, it is possible to lead the
pressure of the high-pressure refrigerant that passes through the
fourth connection port 54 to the pilot electromagnetic valve
60.
[0093] The low-pressure extraction portion 51a is provided at the
first connection port 51. The low-pressure extraction pipe 61a,
which is a capillary tube extending from the pilot electromagnetic
valve 60, is connected to the low-pressure extraction portion 51a.
Consequently, it is possible to lead the pressure of the
low-pressure refrigerant that passes through the first connection
port 51 to the pilot electromagnetic valve 60.
[0094] The pilot electromagnetic valve 60 includes four ports and
the like, the four ports including a high-pressure extraction port
64, a low-pressure extraction port 61, a first action port 62, and
a second action port 63.
[0095] The high-pressure extraction port 64 is connected to the
high-pressure extraction portion 54a via the high-pressure
extraction pipe 64a. The low-pressure extraction port 61 is
connected to the low-pressure extraction portion 51a via the
low-pressure extraction pipe 61a. The first action port 62 is
connected to the first communication portion 55a via the first
pilot pipe 62a. The second action port 63 is connected to the
second communication portion 56a via the second pilot pipe 63a.
[0096] The controller 7 switches between the first connection state
and the second connection state, the first connection state being a
state in which, by causing an excitation coil, which is not
illustrated, included in the pilot electromagnetic valve 60 to
generate a magnetic field and moving a valve part against a force
received from a spring and the like, a refrigerant pressure
extracted by the low-pressure extraction port 61 is caused to act
on the first action port 62 while a refrigerant pressure extracted
by the high-pressure extraction port 64 is caused to act on the
second action port 63, the second connection state being a state in
which, by applying no voltage, a refrigerant pressure extracted by
the low-pressure extraction port 61 is caused to act on the second
action port 63 while a refrigerant pressure extracted by the
high-pressure extraction port 64 is caused to act on the first
action port 62.
[0097] The valve body 57 included in the four-way switching valve
body 50 of the four-way switching valve 12 is preferably
constituted by a resin other than nylon 66 and more preferably
constituted by a resin containing at least one selected from the
group consisting of PBT (polybutylene terephthalate), PET
(polyethylene terephthalate), PTFE (polytetrafluoroethylene), and
PPS (polyphenylene sulfide), from the point of view of favorable
lubricity, favorable suppression of corrosion due to the
refrigerant containing CF.sub.3I or a decomposition product
thereof, and suppression of a decrease in the strength due to
corrosion.
[0098] With regard to constituent components other than the valve
body 57 of the four-way switching valve 12, for example, a
protective film of a copper alloy or the like in which the
percentage of zinc is 10 w % or less may be formed on a surface
with which the refrigerant comes into contact.
[0099] (5) Structure of Outdoor Heat Exchanger 13 and Indoor Heat
Exchanger 18
[0100] As illustrated in FIG. 6, the outdoor heat exchanger 13 and
the indoor heat exchanger 18 are each configured such that a
plurality of heat transfer fins 42 extend through and fixed to a
plurality of heat transfer tubes 41.
[0101] From the point of view of favorable heat transfer properties
and favorable suppression of corrosion due to the refrigerant
containing CF.sub.3I or a decomposition product thereof, such heat
transfer tubes 41 can be constituted by a copper alloy in which the
percentage of zinc is 10 wt % or less and is preferably constituted
by a copper alloy in which the percentage of zinc is 5 wt % or
less, and the heat transfer tubes 41 in which the percentage of
copper is substantially 100% may be used.
[0102] From the point of view of favorable suppression of corrosion
due to the refrigerant containing CF.sub.3I or a decomposition
product thereof, the liquid refrigerant connection pipe 6 and the
gas refrigerant connection pipe 5 are also preferably constituted
by a copper alloy in which the percentage of zinc is 10 wt % or
less and is more preferably constituted by a copper alloy in which
the percentage of zinc is 5 wt % or less, and the liquid
refrigerant connection pipe 6 and the gas refrigerant connection
pipe 5 in each of which the percentage of copper is substantially
100% may be used.
[0103] (6) Structure of Flare Connection Portion 8
[0104] The refrigerant circuit 10 is constituted by a plurality of
refrigerant pipes that are connected to each other. As illustrated
in FIG. 7, a connection portion of these pipes is constituted by a
flare connection portion 8 including a flare nut 83, a joint body
84, an O-ring, which is not illustrated, and the like.
[0105] A case in which a first refrigerant pipe 81 and a second
refrigerant pipe 82 that constitute part of the refrigerant circuit
10 are connected will be described here as an example.
[0106] An end portion of the first refrigerant pipe 81 includes a
flare part 81a having a diameter that increases toward an end
portion. The flare nut 83 is provided on the side of the first
refrigerant pipe 81 including the flare part 81a.
[0107] An end portion of the second refrigerant pipe 82 is fixed to
the joint body 84. The joint body 84 is a cylindrical member that
has, at an outer peripheral portion, a screw groove in
correspondence with a screw groove provided at the inner periphery
of the flare nut 83. A part of the joint body 84 facing the flare
part 81a has a shape in correspondence with the flare part 81a.
[0108] In the above configuration, the first refrigerant pipe 81
and the second refrigerant pipe 82 are coupled to each other by the
flare nut 83 being screwed with respect to the joint body 84.
[0109] From the point of view of favorable suppression of corrosion
due to the refrigerant containing CF.sub.3I or a decomposition
product, the flare nut 83 described above can be a copper alloy in
which the percentage of zinc is 10 wt % or less and is preferably a
copper alloy in which the percentage of zinc is 5 wt % or less.
[0110] (7) Features of Embodiment
[0111] In an existing refrigerant circuit of a refrigerant cycle
apparatus in which a refrigerant such as R410A or the like is used,
for example, brass such as JIS C3604 or the like in which zinc is
blended by approximately 30% is used as a balance weight of a
compressor, and brass in which zinc is blended by approximately 30%
is also used as a needle of an expansion valve. In the existing
refrigerant circuit, a bearing including a bronze back metal on
which an abrasion-resistant film of PTFE is formed is used as a
bearing of the compressor, and nylon 66 is used as a valve body of
a four-way switching valve.
[0112] However, the inventors confirmed that, when these components
are exposed together with a refrigerant containing CF.sub.3I to an
environment of approximately 175.degree. C. for two weeks,
corrosion occurs remarkably on the components, although no
corrosion was confirmed on the components exposed together with
R410A to the same condition. Specifically, corrosion progressed on
brass to an extent that metallic luster was lost. A color change to
brown was also confirmed on bronze. In addition, a color change to
brown occurred on nylon 66, and nylon 66 changed to be brittle.
Moreover, it was confirmed that it is not possible to sufficiently
suppress corrosion on these components by only mixing a
refrigerating-machine oil in the refrigerant containing CF.sub.3I
and further inputting an additive agent, such as an acid scavenger.
In contrast to this, when PET, PBT, and PTFE were exposed together
with the refrigerant containing CF.sub.3I to an environment of
approximately 175.degree. C. for two weeks, corrosion found on
nylon 66 was not confirmed.
[0113] Thus, as described above, a metal in which the percentage of
zinc is suppressed to 10% or less is substituted, and a resin other
than nylon 66 is substituted in the air conditioning apparatus 1 of
the present embodiment. Consequently, it is possible, when the
refrigerant containing CF.sub.3I is used as a working refrigerant,
to suppress corrosion on a component due to the refrigerant
containing CF.sub.3I.
[0114] Meanwhile, it was confirmed that aluminum or an aluminum
alloy melts when exposed to a high temperature of approximately
175.degree. C. under the presence of the refrigerant containing
CF.sub.3I while it was also confirmed that melting was suppressed
under a low temperature environment of 100.degree. C. or less.
Therefore, in the air conditioning apparatus 1 that is controlled,
as described above, by the controller 7 such that the maximum
temperature of a portion with which a fluid that flows in the
refrigerant circuit 10 comes into contact is 100.degree. C. or
less, conditions required as a component is also taken into
consideration, and aluminum or an aluminum alloy is usable.
[0115] (8) Modification
[0116] (8-1) Modification A
[0117] In the aforementioned embodiment, regarding members of the
refrigerant circuit 10, a case in which the entirety of components
are constituted by a corrosion resistance material has been
described. In contrast to this, as long as satisfying conditions
required for the components, the above-described corrosion
resistance material may be provided as a protecting layer on these
components by plating or the like, and parts of components other
than the protecting layer may be constituted by a material other
than a corrosion resistance material.
[0118] (9) Additional Remarks
[0119] The component may be constituted by a corrosion resistance
material in the entirety thereof, or a part of the component to be
in contact with the refrigerant may be coated with a protecting
layer containing a corrosion resistance material while parts other
than the protecting layer may be constituted by a material other
than a corrosion resistance material.
[0120] The corrosion resistance material here is preferably a metal
in which the percentage of zinc is 5 wt % or less and may be a
copper alloy in which the percentage of zinc is 5 wt % or less.
(10) Others Although an embodiment of the present disclosure have
been described above, it should be understood that various changes
in the forms and the details are possible without deviating from
the spirit and the scope of the present disclosure described in the
claims.
REFERENCE SIGNS LIST
[0121] 1 air conditioning apparatus (refrigerant cycle
apparatus)
[0122] 5 gas refrigerant connection pipe (refrigerant pipe,
component)
[0123] 6 liquid refrigerant connection pipe (refrigerant pipe,
component)
[0124] 7 control unit
[0125] 9 expansion valve
[0126] 10 refrigerant circuit
[0127] 11 compressor
[0128] 12 four-way switching valve
[0129] 13 outdoor heat exchanger
[0130] 18 indoor heat exchanger
[0131] 26 lower bearing (bearing, component)
[0132] 30 balance weight (component)
[0133] 31 pin bearing (bearing, component)
[0134] 35 upper bearing (bearing, component)
[0135] 41 heat transfer tube (component)
[0136] 57 valve body (component)
[0137] 81 first refrigerant pipe (refrigerant pipe, component)
[0138] 82 second refrigerant pipe (refrigerant pipe, component)
[0139] 83 flare nut (component)
[0140] 93 valve body (component)
[0141] 93b needle (component)
CITATION LIST
Patent Literature
[0142] PTL 1: Japanese Unexamined Patent Application Publication
No. 2017-149943
* * * * *