FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
REFRIGERATION CYCLE DEVICE
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
- 2 -
DESCRIPTION
TECHNICAL FIELD
[0001] The present disclosure relates to a refrigeration cycle device.
5 BACKGROUND ART
[0002] The refrigerant used for a refrigeration cycle device is. The hydrocarbons
having 1 to 4 carbon atoms have a further lower GWP value than saturated fluorinated
hydrocarbon compounds (hydrofluorocarbons), which are refrigerants having a
relatively low GWP value.
10 [0004] However, the hydrocarbons having 1 to 4 carbon atoms have higher
flammability than hydrofluorocarbons. For example, in the international standard
ISO-817, which defines safety classification for refrigerants, R-32 (difluoromethane),
one of the hydrofluorocarbons, is registered as lower flammability (Class 2L), and on
the other hand, R-290, R-1270, and R-600a are registered as higher flammability (Class
15 3).
[0005] For example, when a refrigerant having high flammability, such as a
hydrocarbon having 1 to 4 carbon atoms, is used as the refrigerant for a refrigeration
cycle device, it is preferable to take a measure of making the refrigerant recognizable
by the sense of smell or the sense of vision. In addition, to suppress the dissolution of
20 the refrigerant into a refrigeration oil and to reduce the amount of the refrigerant to
currently restricted by, for example, the Fluorocarbon Emissions Control Act (enacted
on April 2015). Specifically, the upper limit is set on the Global Warming Potential
(GWP) value of the refrigerant to be used. Thus, use of a refrigerant having a further
low GWP is needed.
25 [0003] In recent years, for example, hydrocarbons having 1 to 4 carbon atoms such as
R-290 (propane), R-1270 (propylene), R-600a (isobutane) are examined as the
refrigerant having a low GWP value
be filled, it is preferred to use a refrigeration oil having a low solubility with the
refrigerant.
- 3 -
[0006] As the measure of making the refrigerant recognizable by the sense of smell, for
example, Patent Literature 1 (Japanese Patent Laying-Open No. 2020-112285)
discloses a method including mixing a sulfur-based odorant such as mercaptan, sulfide,
or thiophene with the refrigerant to detect the leakage of the refrigerant by an
5 unpleasant odor. Patent Literature 1 also discloses that use of polyalkylene glycol as a
refrigeration oil enables reduction in the amount of the refrigerant dissolved in the
refrigeration oil, and can thus ensure necessary refrigeration cycle performance with a
lower amount of the refrigerant to be filled.
[0007] Patent Literature 2 (Japanese Patent Laying-Open No. 2002-38135) discloses
10 that tetrahydrothiophene (THT) is preferable as an odorant since it does not react with
the material for the refrigerating circuit, has miscibility with the refrigerant, and has
miscibility with refrigeration oil.
CITATION LIST
PATENT LITERATURE
15 [0008] PTL 1: Japanese Patent Laying-Open No. 2020-112285
PTL 2: Japanese Patent Laying-Open No. 2002-38135
SUMMARY OF INVENTION
TECHNICAL PROBLEM
[0009] However, the inventors have found the following: sulfur-based odorants such as
20 THT have polarity due to the bias of charge in the molecule; thus, when a refrigeration
oil having high polarity is used, the sulfur-based odorant is dissolved in the
refrigeration oil in a compressor so that the amount of the sulfur-based odorant that
circulates in the refrigerant circuit with the refrigerant is reduced; and when the
refrigerant is released from the refrigeration cycle device, the refrigerant is hardly
25 detectable by the sense of smell. In addition, since polyalkylene glycol contain a large
amount of oxygen (O), which is an element having a large electronegativity in the
molecular structure, they are refrigeration oils having high polarity and dissolve a large
amount of sulfur-based odorants depending on the composition.
[0010] The present disclosure has been made in view of the above problems, and an
- 4 -
object of the present disclosure is to provide a refrigeration cycle device that suppresses
the dissolution of a sulfur-based odorant in polyalkylene glycol and makes the leakage
of a refrigerant recognizable by the sense of smell.
SOLUTION TO PROBLEM
5 [0011] A refrigeration cycle device according to the present disclosure includes a
refrigerant circuit including a compressor, wherein
a refrigerant is enclosed in the refrigerant circuit,
the refrigerant contains a hydrocarbon having 1 to 4 carbon atoms and a sulfurbased odorant,
10 the compressor is filled with a refrigeration oil,
the refrigeration oil contains polyalkylene glycol, and
a ratio of a number of oxygen atoms to a number of carbon atoms in a
molecular structure of polyalkylene glycol is 0.50 or less.
ADVANTAGEOUS EFFECT OF INVENTION
15 [0012] According to the present disclosure, a refrigeration cycle device that suppresses
the dissolution of the sulfur-based odorant in polyalkylene glycol and makes the
leakage of the refrigerant recognizable by the sense of smell can be provided.
BRIEF DESCRIPTION OF DRAWINGS
[0013] Fig. 1 is a schematic configuration diagram showing one example of a
20 refrigeration cycle device according to an embodiment 1.
Fig. 2 is a schematic cross-sectional view showing one example of a compressor
of the refrigeration cycle device according to embodiment 1.
Fig. 3 is a graph showing a relationship between the concentration of
tetrahydrothiophene in an enclosed refrigerant and the concentration of
25 tetrahydrothiophene in collected refrigerant gas.
Fig. 4 is a graph showing a relationship between the concentration of
tetrahydrothiophene in a sample gas and the odor index (equivalent value).
DESCRIPTION OF EMBODIMENTS
[0014] Hereinafter, the embodiments of the present disclosure will be described with
- 5 -
reference to the drawings. In the drawings, the dimensional relationship of the length,
width, thickness, depth, and the like is appropriately changed for the purpose of clarity
and simplification of the drawing, and does not indicate the actual dimensional
relationship.
5 [0015] Embodiment 1.
First, the outline of the refrigeration cycle device of the present embodiment is
briefly described. Fig. 1 is a schematic configuration diagram showing one example
of the refrigeration cycle device according to embodiment 1. An outdoor unit 1
includes a compressor 3, a condenser 4, an outdoor blower 5, and the others, and
10 compressor 3 and condenser 4 are connected via piping. An indoor unit 2 includes an
expansion valve 6, an evaporator 7, an indoor blower 8, and the others, and expansion
valve 6 and evaporator 7 are connected via piping.
[0016] Compressor 3 of outdoor unit 1 and evaporator 7 of indoor unit 2 are connected
via a gas pipe 10. Condenser 4 of outdoor unit 1 and expansion valve 6 of indoor unit
15 2 are connected via a liquid pipe 9.
[0017] A refrigerant circuit 100 is formed by such a refrigeration cycle device
configuration, and a refrigerant is circulated in refrigerant circuit 100 via liquid pipe 9
and gas pipe 10.
[0018] Compressor 3 compresses the refrigerant that has turned into a gaseous state in
20 gas pipe 10. Condenser 4 cools the gaseous refrigerant that has been compressed by
compressor 3 to form a high-pressure liquid refrigerant or a gas-liquid two-phase
refrigerant. Expansion valve 6 reduces the pressure of the high-pressure liquid
refrigerant or the gas-liquid two-phase refrigerant. Evaporator 7 heats the refrigerant
reduced in pressure to form a low-pressure gaseous refrigerant. Compressor 3 sucks
25 and recompresses the refrigerant that has turned into a low-pressure gaseous state by
evaporator 7.
[0019] Outdoor blower 5 is a constituent that sends air to condenser 4, and is provided
to promote the absorption and release of heat by the heat exchange of the refrigerant
flowing in condenser 4 with air. Indoor blower 8 is a constituent that sends air to
- 6 -
evaporator 7, and is provided to promote the absorption and release of heat by the heat
exchange of the refrigerant flowing in evaporator 7 with air.
[0020] In the present embodiment, the configuration for carrying out the heat exchange
of condenser 4 and evaporator 7 with air is described, but the configuration is not
5 limited to this configuration. For example, condenser 4 and evaporator 7 may be
configured so as to exchange heat with not air but a liquid such as water.
[0021] In the present embodiment, the configuration in which evaporator 7 is provided
in indoor unit 2 is described, but the configuration is not limited to this configuration.
For example, condenser 4 may be arranged on the inside, and evaporator 7 may be
10 arranged on the outside.
[0022] With respect to outdoor unit 1 as described above, for example, a four-way
valve or a combination of a plurality of valves may be arranged, or a switching
mechanism that switches an inlet pipe and a discharge pipe of compressor 3 may be
provided. By providing a switching mechanism, the heat exchanger in outdoor unit 1
15 functions as evaporator 7 and the heat exchanger in indoor unit 2 functions as
condenser 4, whereby heating of the indoor using the outdoor heat is enabled.
[0023] The refrigeration cycle device may be, for example, any of a device capable of
carrying out both cooling and heating, a device capable of carrying out only cooling, or
a device capable of carrying out only heating.
20 [0024] In the present embodiment, the configuration in which expansion valve 6 is
provided in indoor unit 2 is described, but the configuration is not limited to this
configuration. For example, expansion valve 6 may be arranged in outdoor unit 1.
For example, expansion valve 6 may be provided on both outdoor unit 1 and indoor
unit 2. Further, for example, a plurality of indoor units 2 or a plurality of outdoor
25 units 1 may be provided in refrigerant circuit 100.
[0025]
Next, the refrigerant enclosed in the refrigerant circuit in the present
embodiment will be described. The refrigerant contains a main component that
functions as the refrigerant, and further contains a sulfur-based odorant for detecting
- 7 -
the leakage of the refrigerant.
[0026] Herein, the aforementioned "main component" is the component whose
proportion in the total amount of the refrigerant (including the sulfur-based odorant and
the others) (content in the refrigerant) is more than 50% by mass. The content of the
5 main component in the refrigerant is preferably 90% by mass or more, and more
preferably 95% by mass or more.
[0027] The main component that functions as the refrigerant is a hydrocarbon having 1
to 4 carbon atoms. Examples of the hydrocarbon having 1 to 4 carbon atoms include
R-290 (propane), R-1270 (propylene), and R-600a (isobutane). The hydrocarbon
10 having 1 to 4 carbon atoms is preferably propane, propylene, or a mixture thereof.
This is because they have an operating pressure suitable for use for the refrigeration
cycle device. In view of oxidation stability, propane is more preferable. Propane has
a GWP value significantly as low as 3 and also high cooling performance, and may
thus contribute to the reduction in environmental load during the production and
15 operation of the refrigeration cycle device.
[0028] (Sulfur-based odorant)
The sulfur-based odorant blended in the refrigerant is an odorant containing a
sulfur element. Examples of the sulfur-based odorant include mercaptans, sulfides,
and thiophenes. Examples of mercaptans include tertiary butyl mercaptan (TBM) and
20 ethyl mercaptan (EM); examples of sulfides include dimethyl sulfide (DMS) and
diethyl sulfide (DES); and examples of thiophenes include tetrahydrothiophene (THT).
These sulfur-based odorants are compounds that have been used in fuel gas and have an
unpleasant odor. One of these sulfur-based odorants may be used singly, or two or
more thereof may be used in combination.
25 [0029] The sulfur-based odorant is preferably TBM, EM, DMS, THT, which are also
used in fuel gas for households, or a mixture thereof. Mixing a sulfur-based odorant
used in fuel gas for households in the refrigerant enables the leakage of the refrigerant
to be easily detected by an unpleasant odor inherent in the sulfur-based odorant.
[0030] The sulfur-based odorant is more preferably THT. THT is chemically stable
- 8 -
as compared with TBM, EM, DMS and the like, so that it hardly causes a
decomposition reaction or a corrosion reaction in the refrigerant circuit, and THT also
hardly causes solidification in the refrigerant circuit because of its melting point as low
as -96C.
5 [0031] The content of the sulfur-based odorant is preferably 50 ppm by weight or more
and less than 1,100 ppm by weight. The reason for this is as follows: when the
content of the sulfur-based odorant is within the above range, the leakage of the
refrigerant from the refrigerant circuit can be easily detected and a not excessively
unpleasant odor is obtained. The content of the sulfur-based odorant is more
10 preferably 90 ppm by weight or more and less than 1026 ppm by weight, and further
preferably 176 ppm by weight or more and less than 987 ppm by weight.
[0032]
In the present embodiment, the refrigeration cycle device includes a compressor.
The refrigerant passes through the inside of the compressor. The compressor contains
15 a refrigeration oil that contains polyalkylene glycol as a main component.
[0033] Fig. 2 is a schematic cross-sectional view showing one example of the
compressor of the refrigeration cycle device according to the present embodiment.
Compressor 3 includes a shell 11, as shown in Fig. 2. Shell 11 includes a compression
mechanism 12 in the inside thereof, and includes an electric motor 13 which drives
20 compression mechanism 12. In addition, an inlet pipe 14 for allowing the refrigerant
to be flowed into the inside and a discharge pipe 15 for allowing the refrigerant to be
flowed to the outside are connected to shell 11. An accumulator 16 which separates
gas and liquid in the refrigerant and sends steam into inlet pipe 14 is connected to the
upstream side of inlet pipe 14.
25 [0034] The refrigerant that has passed through accumulator 16 flows from inlet pipe 14
into compression mechanism 12 in shell 11. The refrigerant that has flowed into
compression mechanism 12 is compressed to have high temperature and high pressure,
and is discharged from discharge pipe 15. That is, compression mechanism 12 is
configured to compress the refrigerant that has flowed from inlet pipe 14 into shell 11
- 9 -
and discharge the refrigerant from discharge pipe 15.
[0035] Compression mechanism 12 is a rotary-type compression mechanism composed
of a combination of a rolling piston 17 and a vane (not shown) and the like. The
refrigerant is compressed by changing the volume of a space surrounded by the inner
5 peripheral surface of a cylinder chamber 19 of a cylinder 18 and the outer peripheral
surface of rolling piston 17 and the vane (not shown) by an eccentric rotary motion of
rolling piston 17.
[0036] The compressed refrigerant is discharged from a discharge hole 21 of an upper
bearing 20 to a muffler space 22, and then discharged from a discharge hole 24 of a
10 discharge muffler 23 into shell 11. The discharged refrigerant passes through a gap in
electric motor 13 (such as a gap between an electric motor rotor 25 and an electric
motor stator 26 or a groove provided on the outer peripheral surface of the electric
motor stator 26), and is then discharged from discharge pipe 15 to the downstream side
of the refrigerant circuit 100.
15 [0037] Compressor 3 has a sliding part on the inside of compression mechanism 12.
For lubrication of the sliding part, a refrigeration oil is stored in an oil reservoir part 27,
which is located below compressor 3. The refrigeration oil stored in oil reservoir part
27 is supplied through an oil supply hole (not shown) provided in the shaft of a driving
shaft 28 to the sliding part in the inside of compression mechanism 12 by pumping
20 action. The refrigeration oil is brought into contact with the refrigerant in compressor
3.
[0038]
Next, the refrigeration oil that fills the inside of the compressor for lubrication
in the present embodiment will be described. The main component which functions
25 as the refrigeration oil is polyalkylene glycol (PAG).
[0039] Herein, the aforementioned "main component" is the component whose
proportion in the total amount of the refrigeration oil is more than 50% by mass. The
content of the main component in the refrigeration oil is preferably 80% by mass or
more, and more preferably 90% by mass or more.
- 10 -
[0040] PAG is a polymer of at least one selected from the group consisting of an
ethylene oxide group (EO group) and a propylene oxide group (PO group) and is
represented by the following chemical formula.
[0041]
5 [Formula 1]
[0042] In the above chemical formula 1, m and n are each an integer of 0 or more and
represent the number of EO groups and PO groups, and R1 and R2 are a hydrogen atom
(H) or a hydrocarbon chain having one or more carbon atoms (C). The arrangement
10 of EO groups and PO groups may be any of a random copolymer, an alternating
copolymer, and a block copolymer.
[0043] In the above chemical formula 1, m and n preferably satisfy the relationships of
the following formulas (1) and (2).When the relationships of the following formulas (1)
and (2) are not satisfied, PAG may be solidified at low temperatures. R1 and R2 are
15 preferably a hydrocarbon chain having one or more carbon atoms (C). When R1 and
R2 are a hydrogen atom (H), the hygroscopicity of PAG increases, and the moisture
may be mixed.
m + n  100 ... formula (1)
n/m + n  0.20 ... formula (2)
20 [0044] (Ratio of number of oxygen atoms to number of carbon atoms in molecular
structure of PAG)
The ratio of the number of oxygen atoms (O) to the number of carbon atoms (C)
in the molecular structure of PAG (O/C ratio) (hereinafter, also simply referred to as
the "O/C ratio") is 0.50 or less. When the O/C ratio is 0.50 or less, the amount of the
25 sulfur-based odorant dissolved in PAG is small, and the refrigerant released from the
refrigerant circuit is recognizable by the sense of smell. The O/C ratio is preferably
0.43 or less, and more preferably 0.39 or less. The lower limit of the O/C ratio is not
- 11 -
particularly limited, and the O/C ratio may be 0.25 or more, or may be 0.30 or more.
[0045] Other refrigeration oils may be mixed in the refrigeration oil, as long as the O/C
ratio in the molecular structure of PAG is lower than that of PAG. Examples of other
refrigeration oils include polyol ester, polyvinyl ether, alkylbenzene, alkylnaphthalene,
5 mineral oil, poly -olefin, or a mixture thereof. Since polyol ester and polyvinyl ether
have low miscibility with a hydrocarbon having 1 to 4 carbon atoms like PAG, the
amount of the refrigerant to be dissolved therein is small so that the amount of the
refrigerant to be filled can be reduced. Accordingly, polyol ester and polyvinyl ether
are preferable.
10 [0046] The refrigeration oil may contain an antioxidant, an acid scavenger, or an
extreme-pressure agent (anti-wear agent) as a lubricant additive.
[0047] Examples of the antioxidant include phenol-based antioxidants such as 2,6-ditert-butyl-4-methyl phenol, 2,6-di-tert-butyl-4-ethylphenol, and 2,2'-methylenebis(4-
methyl-6-tert-butylphenol), and amine-based antioxidants such as phenyl--
15 naphthylamine and N,N'-di-phenyl-p-phenylenediamine.
[0048] Examples of the acid scavenger include epoxy compounds such as phenyl
glycidyl ether, alkyl glycidyl ester, alkyl glycidyl ether, alkylene glycol glycidyl ether,
cyclohexene oxide, -olefin oxide, and epoxidized soybean oil. The acid scavenger is
preferably alkyl glycidyl ester, alkyl glycidyl ether, or -olefin oxide.
20 [0049] Examples of the extreme-pressure agent (anti-wear agent) include phosphorusbased extreme-pressure agents such as phosphate esters, thiophosphate esters, acid
phosphate esters, phosphite esters, acid phosphite esters and amine salts thereof. The
extreme-pressure agent (anti-wear agent) is preferably a phosphate ester, a
thiophosphate ester, or a mixture thereof. Specifically, tricresyl phosphate (O=P25 (OC7H7)3), triphenyl phosphorothioate (S=P-(OC6H5)3), triphenyl phosphate (O=P-
(OC6H5)3), derivatives thereof, or a mixture thereof is preferable.
[0050] The refrigeration oil may contain an oxygen scavenger. Examples of the
oxygen scavenger include sulfur-containing aromatic compounds such as 4,4'-thiobis(3-
methyl-6-tert-butylphenol), diphenyl sulfide, dioctyl diphenyl sulfide, dialkyl
- 12 -
diphenylene sulfide, benzothiophene, dibenzothiophene, phenothiazine, benzothiapyran,
thiapyran, thianthrene, dibenzothiapyran, and diphenylene disulfide; aliphatic
unsaturated compounds such as various olefins, diene, and triene; and cyclic terpenes
having an unsaturated bond, such as -pinene, -pinene, limonene, and phellandrene.
5 The oxygen scavenger is preferably an aliphatic unsaturated compound or a cyclic
terpene having an unsaturated bond.
[0051] Also, the refrigeration oil may contain a fluorescent agent, a colorant, or the like
so as to visually detect the refrigerant and the refrigeration oil.
[0052] However, if moisture is contained in the refrigeration oil, the deterioration of
10 the refrigerant, refrigeration oil, and materials in the compressor may be promoted, and
thus, it is necessary to control the amount of the moisture contained in the refrigeration
oil to be filled so as to be 100 ppm by weight or less.
[0053] The refrigeration cycle device has been described above with reference to a
mode in which a rotary compressor is used as compressor 3, but the refrigeration cycle
15 device is not limited thereto. For example, a low-pressure shell or high-pressure shell
scroll compressor, a screw compressor, or the others may be used as compressor 3.
[0054]
The difference between the HSP distance between PAG and the sulfur-based
odorant and the HSP distance between PAG and the refrigerant is -2.0 or more.
20 Hereinafter, the HSP distance between PAG and the sulfur-based odorant is sometimes
referred to as "the HSP distance to the sulfur-based odorant", and the HSP distance
between PAG and the refrigerant is sometimes referred to as "the HSP distance to the
refrigerant".
[0055] Herein, "HSP" means "Hansen Solubility Parameter", and is a value used to
25 predict the solubility of substances based on the idea that "substances having similar
intramolecular interactions are easily dissolved in each other". Specifically, HSP is
represented as a three-dimensional vector by three parameters (dD, dP, and dH), which
are a dispersion term, a polar term, and a hydrogen bond term, respectively. As for
two substances, the solubility is higher, as their vectors (dD, dP, and dH) are similar.
- 13 -
[0056] The HSP of a substance can be cited from the database and calculated from the
molecular structure by using computer software, HSPiP (Hansen Solubility Parameter
in Practice). When HSPiP is not used, the calculation method for HSP is described in
literatures (e.g., Van Krevelen, Properties of Polymers, 4th Edition, 2009).
5 [0057] The "HSP distance" is the distance between HSP values of two substances, and
is a value indicating the similarity of vectors ((dD1, dP1, and dH1) and (dD2, dP2, and
dH2)) of two substances. Specifically, it is determined by the following formula (3)
based on the above three parameters (dD, dP, and dH). With respect to two
substances whose HSP distances are to be calculated, dD, dP, and dH of one substance
10 are represented by dD1, dP1, and dH1, and dD, dP, and dH of another substance are
represented by dD2, dP2, and dH2, in the following formula (3). As for two
substances, the solubility is lower, as the HSP distance is larger.
HSP distance = {4  (dD1-dD2)2
+ (dP1-dP2)2
+ (dH1-dH2)2
}
0.5
... formula (3)
[0058] As the amount of the sulfur-based odorant dissolved in PAG is smaller, the
15 amount of the sulfur-based odorant that circulates in the refrigerant circuit is larger, and
the refrigerant released from the refrigerant circuit is recognizable by the sense of smell.
In addition, as the amount of the refrigerant excluding the sulfur-based odorant
dissolved in PAG is larger, the amount of the sulfur-based odorant dissolved in PAG is
smaller due to the influence of the refrigerant excluding the sulfur-based odorant
20 dissolved in PAG for the reason described below, and as a result, the amount of the
sulfur-based odorant that circulates in the refrigerant circuit is larger, so that the
refrigerant released from the refrigerant circuit is recognizable by the sense of smell.
Namely, as the difference between the HSP distance to the sulfur-based odorant and the
HSP distance to the refrigerant (the HSP distance to the sulfur-based odorant - the HSP
25 distance to the refrigerant) is larger, the amount of the sulfur-based odorant dissolved in
PAG is smaller, a larger amount of the sulfur-based odorant is contained in the
refrigerant released from the refrigerant circuit, and the refrigerant released from the
refrigerant circuit is recognizable by the sense of smell.
[0059] When the difference between the HSP distance to the sulfur-based odorant and
- 14 -
the HSP distance to the refrigerant is -2.0 or more, the amount of the sulfur-based
odorant dissolved in PAG is sufficiently small, and the refrigerant released from the
refrigerant circuit is recognizable by the sense of smell. The difference between the
HSP distance to the sulfur-based odorant and the HSP distance to the refrigerant is
5 preferably -0.5 or more, and more preferably 0 or more. The upper limit of the
difference between the HSP distance to the sulfur-based odorant and the HSP distance
to the refrigerant is not particularly limited, and the difference may be 5.0 or less, or 3.0
or less.
EXAMPLES
10 [0060] Hereinafter, the present disclosure will be described in detail with reference to
Examples, but the present disclosure is not limited to these Examples.
[0061]
Refrigerant gas in which a refrigerant, a sulfur-based odorant, and PAG were
mixed was prepared under the conditions shown in Table 1 to evaluate the amount of
15 the sulfur-based odorant released with the refrigerant when the refrigerant, the sulfurbased odorant, and PAG were mixed. In PAG used, m = 7, n = 36, and R1 and R2
were CH3. The concentration of the sulfur-based odorant (THT) in the refrigerant gas
is shown in Table 2.
[0062]
- 15 -
[Table 1]
Test container Portable reactor
(TVS-N2-50 manufactured by Taiatsu Techno Corporation)
Container capacity 50cm3
Refrigerant
R-290
(ECO FREEZE 290 manufactured by IWATANI
INDUSTRIAL GASES CORPORATION)
Mass of refrigerant 10.0g
Sulfur-based
odorant
THT
(T0114 manufactured by Tokyo Chemical Industry Co., Ltd.)
Mass of PAG 10.0g
Amount of
moisture in PAG
100 ppm by weight or less based on the total amount of the
refrigeration oil
[0063]
[Table 2]
Test No. THT Concentration in refrigerant gas
(ppm by weight)
1-1 2.3
1-2 24
1-3 180
1-4 190
1-5 600
1-6 987
1-7 1740
1-8 2230
[0064] The above refrigerant gas was enclosed in a test container, which was shaken at
5 140C to stir the refrigerant gas, and then, the test container was allowed to stand still
at 25C. 24 hours after the start of still standing, a tedlar bag (1-2711-05
manufactured by AS ONE Corporation) was connected to the discharge port of the test
container, and the refrigerant gas was collected at 25C. For the collected refrigerant
gas, the concentration of THT was measured by using a gas chromatography mass
10 spectrometer (JMS-K9 manufactured by JEOL Ltd.).
[0065] The relationship between the concentration of THT in the enclosed refrigerant
gas and the concentration of THT in the collected refrigerant gas is shown in Fig. 3.
The concentration of THT in the collected refrigerant gas was increased in a linear
relation in a range of the concentration of THT in the enclosed refrigerant gas from 2.3
- 16 -
ppm by weight to 987 ppm by weight, and increased in a linear relation with a larger
inclination in a range from 987 ppm by weight to 2,230 ppm by weight. The
expression of the approximate line in Fig. 3 was y = 0.047x in the range of the
concentration of THT from 2.3 ppm by weight to 987 ppm by weight, and y = 1.66x -
5 774 in the range from 987 ppm by weight to 2,230 ppm by weight. Specifically, in
the range of the concentration of THT in the enclosed refrigerant gas from 2.3 ppm by
weight to 987 ppm by weight, the amount of THT released with R-290 was about 4.7%
of the enclosed THT, and the remaining, about 95.3%, kept in a state dissolved in PAG
and was not released as the gas.
10 [0066] Even when THT was mixed in R-290 as described above, THT was dissolved in
PAG, so that only a part of THT in the enclosed refrigerant gas was released with R290, and the refrigerant was demonstrated to be hardly detectable by the sense of smell
when the refrigerant was released from the refrigeration cycle device.
[0067]
15 Each sample gas in which air was mixed with a sulfur-based odorant (THT) was
prepared under the conditions shown in Table 3 to quantitatively evaluate the
relationship between the concentration of the sulfur-based odorant in air and the
intensity of the odor. The concentration of THT in the sample gas is shown in Table 4.
[0068]
- 17 -
[Table 3]
Sampling container Smart Bag PA
(AA-5 manufactured by GL Sciences Inc.)
Air used
High purity air
(ZERO-A manufactured by Sumitomo Seika Chemicals
Company, Limited.)
Air volume 3000cm3
THT used
THT
(T0114 manufactured by Tokyo Chemical Industry Co.,
Ltd.)
Evaluation device
Fragrance analyzer
(FF-2020S system manufactured by SHIMADZU
CORPORATION)
[0069]
[Table 4]
Sample No. THT Concentration in sample gas
(ppb by volume)
2-1 3.0
2-2 10
2-3 100
2-4 300
2-5 1000
2-6 3000
[0070] The odor index (equivalent value) of the above sample gas was measured.
5 Herein, the "odor index" is a numerical expression for the degree of odor using the
human sense of smell, and is a value obtained by multiplying the common logarithm of
the odor concentration of an odor component (the concentration of the odor component
when the odor is diluted with air to the extent that the odor can no longer be sensed by
the human sense of smell) by 10. The "odor index (equivalent value)" is a numerical
10 value corresponding to the odor index and obtained by the measurement with an odor
identification device. In the measurement, nitrogen (N2) was used as the carrier gas,
and the dilution factor of the sample with the carrier gas was set to 100.
[0071] The relationship between the concentration of THT in the sample gas and the
odor index (equivalent value) is shown in Fig. 4. The concentration of THT in the
15 sample gas and the odor index (equivalent value) were in a logarithmic function
- 18 -
relationship. This means that the results following the rule of Weber-Fechner, which
represents the relationship between the concentration of an odor substance and the
intensity of the odor, were obtained. In the present test, high purity air was used as
the gas for diluting THT. However, also in the case where THT is diluted with R-290,
5 the same correlation is considered to be obtained for the concentration of THT and the
odor index (equivalent value) because R-290 is odorless.
[0072] The odor index has a relationship with the odor intensity in the 6-step odor
intensity display method as shown in Table 5. The concentrations of THT shown in
Table 5 were the results of the determination of the concentration of THT
10 corresponding to an odor intensity of 2.5 to 3.5, based on the relationship between the
concentration of THT and the odor index (equivalent value) in Fig. 4.
[0073]
[Table 5]
Odor
intensity Detail Odor index
THT
Concentration
(ppb by volume)
0 Odorless 0 to less than 10 less than 2.1 1 An odor is sensed with difficulty
2
A weak odor whose odor source
can be seen 10 to 15 2.1 to 10
3 An odor is sensed with ease 12 to 18 4.1 to 29
4 Strong odor 14 to less than 21 7.8 to less than 77
5 Intense odor 21 or more 77 or more
[0074] To recognize the refrigerant by the sense of smell, the presence of the sulfur15 based odorant contained in the refrigerant is needed to be recognized. Accordingly,
the odor intensity of the refrigerant is preferably 2 (a weak odor whose odor source can
be seen) or more, and more preferably 3 (an odor is sensed with ease) or more.
[0075] The refrigerant released from the refrigerant circuit into the atmosphere is
diluted with air, and the concentration of THT is reduced. The international standard
20 ISO-13734 relating to the odorization treatment of natural gas states that the natural gas
is needed to have an odor even when being diluted to 20% by volume of the lower
flammability limit (LFL). The LFL of R-290 is 21,000 ppm by volume in ISO-817,
- 19 -
and 20% of the LFL is thus 4,200 ppm by volume.
[0076] As for the odorization treatment of gas, the Japanese ordinance on the
odorization treatment of gas (an ordinance that establishes technical standards of gas
facilities (Ordinance of the Ministry of International Trade and Industry No. 111 of
5 2000)) states that it is necessary to enable "the presence or absence of an odor to be
sensed when the mixed volume ratio of gas to the air is 1/1,000". Accordingly, when
the concentration of R-290 is diluted to 1,000 ppm by volume in the air, R-290 needs to
be recognized by the odor, and thus, a stronger odorization treatment than ISO-13734 is
required.
10 [0077] In mixed gas of the air and THT in which 1,000 ppm of R-290 is contained,
THT needs to be contained in a concentration of 2.1 ppb by volume or more in order to
make the odor intensity of the mixed gas 2 or more. That is, in the mixed gas of R290 and THT, 2.1 ppm by volume (4.2 ppm by weight) or more of THT is needed to be
contained.
15 [0078] To make the odor intensity of the mixed gas to 3 or more, THT needs to be
contained in a concentration of 4.1 ppb by volume or more. That is, in the mixed gas
of R-290 and THT, 4.1 ppm by volume (8.2 ppm by weight) or more of THT needs to
be contained.
[0079] As described above, the concentration of THT needed to recognize the
20 refrigerant by the sense of smell was demonstrated by quantitatively clarifying the
relationship between the concentration of THT in the sample gas and the intensity of
the odor.
[0080] In the results of evaluation test 1 shown in Fig. 3, the concentrations of THT to
make the THT concentrations in the released refrigerant gas 4.2 ppm by weight and 8.2
25 ppm by weight are 90 ppm by weight and 176 ppm by weight, respectively. Thus,
when PAG used in evaluation test 1 is used in the refrigeration cycle device, the
refrigerant gas released from the refrigerant circuit diluted to 1/1,000 in the air is
recognizable by the sense of smell, as long as the concentration of THT in the
refrigerant is 90 ppm by weight or more.
- 20 -
[0081] Meanwhile, when the odor intensity of the air containing the refrigerant gas is 5
(intense odor), the released odor of the refrigerant gas is too unpleasant. In the results
of evaluation test 1 shown in Fig. 3, the concentration of THT to make the
concentration of THT in the released refrigerant 77 ppm by volume (154 ppm by
5 weight) is 514 ppm by volume (1,026 ppm by weight). In other words, when PAG
shown in Table 2 is used in the refrigeration cycle device, the refrigerant gas released
from the refrigerant circuit diluted to 1/1,000 in the air does not become a too
unpleasant odor, as long as the THT concentration in the refrigerant is less than 1,026
ppm by weight.
10 [0082]
To demonstrate the influence on the results of evaluation test 1 by the molecular
structure of PAG, each refrigerant gas in which R-290 containing the sulfur-based
odorant (THT) serving as the refrigerant was mixed with PAG shown in Table 6 was
prepared under the conditions shown in Table 7. The concentration of THT in the
15 refrigerant was 600 ppm by weight so that the odor intensity of the refrigerant
described in Table 5 was 3.
[0083]
[Table 6]
Test No. m n R1 R2 O/C Ratio
1 5 0 H H 0.60
2 9 0 CH3 H 0.53
3 10 6 CH3 CH3 0.43
4 11 8 H H 0.43
5 11 8 CH3 H 0.43
6 11 8 CH3 CH3 0.42
7 8 13 CH3 H 0.39
8 8 13 CH3 CH3 0.39
9 2 17 H H 0.36
10 7 36 CH3 CH3 0.35
11 8 42 CH3 CH3 0.35
12 0 17 H H 0.35
13 0 16 CH3CH2
CH2CH2
H
0.33
[0084]
- 21 -
[Table 7]
Test container Portable reactor
(TVS-N2-50 manufactured by Taiatsu Techno Corporation)
Container capacity 50cm3
Refrigerant
R-290
(ECO FREEZE 290 manufactured by IWATANI
INDUSTRIAL GASES CORPORATION)
Mass of refrigerant 10.0g
Sulfur-based
odorant
THT
(T0114 manufactured by Tokyo Chemical Industry Co., Ltd.)
Sulfur-based
odorant mass
6.0mg (600 ppm by weight based on the total amount of R290 and THT)
Mass of PAG 10.0g
Amount of
moisture in PAG
100 ppm by weight or less based on the total amount of the
refrigeration oil
[0085] The values for the molecular structure of PAG shown in Table 6 were
determined based on the number average degree of polymerization of the composition
of each PAG. The O/C ratio is a value representing the ratio of the number of oxygen
5 atoms (O) to the number of carbon atoms (C) in the molecular structure by two
significant figures.
[0086] The above refrigerant gas was enclosed in a test container, which was shaken at
140C to stir the refrigerant gas, and then, the test container was allowed to stand still
at 25C. 24 hours after the start of still standing, a tedlar bag (1-2711-05
10 manufactured by AS ONE Corporation) was connected to the discharge port of the test
container, and the refrigerant gas was collected at 25C. The collected refrigerant gas
was diluted to 1/1,000 with high purity air (ZERO-A manufactured by Sumitomo Seika
Chemicals Company, Limited.), and then, the evaluation of the odor intensity was
carried out by the odor sensory test method with reference to the literature (Journal of
15 Japan Society of Air Pollution, Vol. 27, No. 2, P. A17-A24, 1992). The results of the
odor intensity of the collected refrigerant gas represented by the 6-level odor intensity
display method are shown in Table 8. The evaluation was such that the odor intensity
of 2 or more was rated as "A", and the odor intensity of 2 or more was rated as "B".
The evaluation was carried out by 5 examiners.
- 22 -
[0087]
[Table 8]
Test No. O/C Ratio Odor intensity Evaluation
1 0.58 0 to 1 B
2 0.53 0 to 1 B
3 0.43 2 to 3 A
4 0.43 2 to 3 A
5 0.43 3 to 4 A
6 0.42 3 to 4 A
7 0.39 3 to 4 A
8 0.39 3 to 4 A
9 0.36 3 to 4 A
10 0.35 3 to 4 A
11 0.35 3 to 4 A
12 0.35 2 to 3 A
13 0.33 3 to 4 A
[0088] As a result of the above evaluation, the refrigerant gas in which PAG (Test No.
3 to 13) having an O/C ratio of 0.43 or less was mixed had an odor in the range of the
5 odor intensity of 2 (a weak odor whose odor source can be seen) to the odor intensity of
4 (strong odor), and THT was demonstrated to be contained in the refrigerant gas.
The refrigerant gas in which PAG (Test No. 1 and 2) having an O/C ratio of 0.53 or
more was mixed had an odor in the range of the odor intensity of 0 (odorless) to the
odor intensity of 1 (an odor is sensed with difficulty), and THT was not demonstrated
10 to be contained in the refrigerant gas.
[0089] These results mean that the amount of THT that is dissolved in PAG and not
released with the refrigerant gas can be explained by the ratio of the polar groups (C-OC and C-O-H) in the molecular structure of PAG.
[0090] THT is a polar molecule having a dipole moment due to bias of charge, in a
15 molecule. According to the literature (J. Am. Chem. Soc., Vol. 61, P. 1769-1780,
1939), the magnitude of the dipole moment of THT is 1.87 D. Since the dipole
moments of H2O and CH3OH, which are considered as polar solvents, are 1.9 D and 1.7
D, respectively, it can be seen that THT is a polar molecule having a large dipole
moment.
- 23 -
[0091] Since THT is a polar molecule, THT is incorporated into the molecular chain of
PAG by an electrical interaction with polar groups (C-O-C and C-O-H) of PAG and
dissolved therein. Since PAG having a large O/C ratio has a large number of polar
groups in the molecular structure, a strong electrical interaction of incorporating THT
5 occurs. Consequently, when PAG having a large O/C ratio is mixed with THT, THT
is hardly released.
[0092] Since R-290 does not have a polar group in the molecule, it is a nonpolar
molecule having a significantly small bias of charge. According to the literature (J.
Chem. Phys., Vol. 33, No. 5, P. 1514-1518, 1960), the dipole moment of R-290 is
10 0.083 D, which is smaller, and it can thus be seen that R-290 is a nonpolar molecule.
Thus, the solubility of THT in R-290 is low, and when R-290 is dissolved in PAG, the
solubility of THT in PAG is reduced. Since PAG having a large O/C ratio has a larger
number of polar groups in the molecular structure, the solubility of R-290, which is a
nonpolar molecule, is lower. Since PAG having a low O/C ratio has higher solubility
15 of R-290, a larger amount of R-290 is dissolved in PAG. Accordingly, that the
solubility of THT in PAG is lower and THT is more easily released. It is considered
that, when the O/C ratio is 0.50 or less, the proportion of the polarized group of atoms
in the molecular structure of PAG becomes half or less and that the effect of increasing
the amount of THT released is achieved. Thus, the O/C ratio is preferably 0.50 or less.
20 [0093] From the above results, to circulate THT with R-290 in the refrigerant circuit by
suppressing the dissolution of THT in PAG, PAG having an O/C ratio of 0.43 or less is
preferably used.
[0094] From the results shown in evaluation test 1, the relationship of the O/C ratio and
the odor intensity is considered to be obtained also when a hydrocarbon having 1 to 4
25 carbon atoms other than R-290, a sulfur-based odorant other than THT, and a
refrigeration oil other than PAG are used. The reason for this is as follows:
hydrocarbons having 1 to 4 carbon atoms other than R-290 are nonpolar molecules
having a significantly small bias of charge in the molecule like R-290, and sulfur-based
odorants other than THT are polar molecules like THT. According to the literature (J.
- 24 -
Chem. Phys., Vol. 1, P. 337-340, 1933), it is reported that the dipole moments of
mercaptans are about 1.3 D to 1.5 D, and that the dipole moments of sulfides are about
1.4 D to 1.58 D. Thus, they are polar molecules unlike hydrocarbons having 1 to 4
carbon atoms.
5 [0095]
The results of evaluation test 3 demonstrated that use of PAG having a low O/C
ratio enabled reduction in the solubility of THT in PAG and release of THT with R-290.
However, the difference in the odor intensities of the refrigerants of Test No. 3 to 13 in
PAG cannot be explained. Thus, the correlation between the molecular structure of
10 PAG and the amount of THT released was examined by using HSP. Each HSP of
THT, R-290, and PAG of each Test No. is shown in Table 9. For HSP, HSPiP Ver.
5.3, which is computer software, was used, and PAG of each Test No. was calculated
by the Van Krevelen method.
[0096]
15 [Table 9]
Substance
name
O/C
Ratio dD dP dH HSP distance
to THT
HSP distance
to R-290
THT - 18.6 6.7 6.0 - 14.2
R-290 - 13.1 0.0 0.0 14.2 -
PAG
1 0.58 16.6 5.0 15.7 10.6 17.9
2 0.53 16.7 3.4 11.1 7.2 13.7
3 0.43 15.0 2.0 7.8 8.8 8.9
4 0.43 14.8 1.9 9.9 9.8 10.6
5 0.43 14.9 1.8 8.9 9.3 9.8
6 0.42 15.0 1.8 7.8 8.9 8.9
7 0.39 15.0 1.7 8.5 9.1 9.5
8 0.39 15.0 1.6 7.6 9.0 8.6
9 0.36 15.3 1.7 9.4 9.0 10.5
10 0.35 14.7 1.1 7.3 9.7 8.0
11 0.35 15.0 1.0 7.3 9.3 8.3
12 0.35 15.1 1.7 9.4 9.2 10.4
13 0.33 15.1 1.7 8.2 8.9 9.3
[0097] The HSP distance between R-290 and THT is a larger value than the HSP
distance between PAG and THT, and the solubility of THT in R-290 is lower than the
- 25 -
solubility of THT in PAG. Accordingly, when R-290 is dissolved in PAG, the amount
of THT dissolved in PAG is considered to be reduced.
[0098] As the HSP distance between PAG and THT is larger, the solubility of THT in
PAG is lower. As the HSP distance between PAG and R-290 is smaller, the solubility
5 of R-290 in PAG is larger. Thus, a larger amount of R-290 is dissolved in PAG, and
THT is more hardly dissolved in PAG. Accordingly, it is considered that, as the
difference between the HSP distance between PAG and THT and the HSP distance
between PAG and R-290 is a larger value, the amount of THT dissolved in PAG is
smaller, and a large amount of THT is contained in the refrigerant gas released from the
10 refrigerant circuit. The relationship between the difference between the HSP distance
between PAG and THT and the HSP distance between PAG and R-290, and the odor
intensity in evaluation test 3 is shown in Table 10.
[0099]
[Table 10]
Test No. O/C Ratio Difference in HSP distance Odor intensity
1 0.60 -7.3 0 to 1
2 0.53 -6.5 0 to 1
9 0.36 -1.6 2 to 3
12 0.35 -1.1 2 to 3
4 0.43 -0.8 2 to 3
5 0.43 -0.4 3 to 4
13 0.33 -0.4 3 to 4
7 0.39 -0.3 3 to 4
3 0.43 -0.1 3 to 4
6 0.42 0.0 3 to 4
8 0.39 0.3 3 to 4
11 0.35 1.0 3 to 4
10 0.35 1.6 3 to 4
15 [0100] As a result of the above evaluation, the following was demonstrated: when the
difference between the HSP distance between PAG and THT and the HSP distance
between PAG and R-290 is -1.6 or more, the released refrigerant gas has an odor
intensity of 2 or more; and when the difference is -0.4 or more, the released refrigerant
gas has an odor intensity of 3 or more.
- 26 -
[0101] From the above results, to circulate THT with R-290 in the refrigerant circuit,
PAG having a difference in the HSP distance of -1.6 or more is preferably used, and
PAG having a difference in the HSP distance of -0.4 or more is more preferably used.
[0102] As a result of the present test, the solubility of THT in PAG was successfully
5 demonstrated in detail with the use of HSP. However, HSP is needed to be calculated
from the molecular structure of PAG. On the other hand, the O/C ratio can be easily
analyzed by using a CHNSO element analyzer even in a state where the molecular
structure is unknown.
[0103]
10 By using a commercially available air conditioner for households (indoor unit
model number: MSZ-GV5620S/outdoor unit model number: MUCZ-G5620S
manufactured by Mitsubishi Electric Corporation) having a refrigerant circuit, the
refrigerant gas released from the refrigerant circuit was collected. In the refrigerant
circuit, 450 g of R-290 was enclosed as the main component of the refrigerant, and 290
15 mg (643 ppm by weight based on the mass of the refrigerant) of THT was enclosed as
the sulfur-based odorant. In the compressor, 400 g of PAG (Test No. 10 of evaluation
test 3) used in evaluation test 1 was enclosed as the refrigeration oil.
[0104] The air conditioner for households was operated, and then, while stopping the
air conditioner for households, the refrigerant gas was released from the point between
20 the expansion valve and the evaporator and collected in a tedlar bag (1-2711-05
manufactured by AS ONE Corporation). The collected refrigerant gas was diluted to
1/1,000 with using high purity air (ZERO-A manufactured by Sumitomo Seika
Chemicals Company, Limited.), and then, the sensory evaluation of the odor was
carried out. The sensory evaluation was carried out by 5 examiners as in evaluation
25 test 3.
[0105] As the result, the odor of the refrigerant gas was an odor intensity of 3 to 4.
For ascertainment, the concentration of THT of the collected refrigerant gas was
analyzed by using a gas chromatography mass spectrometer (JMS-K9 manufactured by
JEOL Ltd.) as in evaluation test 1, and as the result, THT was contained in the
- 27 -
refrigerant gas in a concentration of 80 ppm by weight (40 ppm by volume). That is,
the THT concentration was 40 ppm by volume when the collected refrigerant gas was
diluted to 1/1,000 with high purity air. Accordingly, it corresponds to the odor
intensity of 4 in the odor intensity in evaluation test 2, and it was demonstrated to be
5 not inconsistent with the results of the sensory evaluation.
[0106] From the above results, the following was demonstrated: when PAG having a
low solubility of THT is used, the dissolution of THT in PAG is suppressed, THT is
allowed to circulate in the refrigerant circuit with R-290, and the refrigerant gas
released from the refrigerant circuit is recognizable by the sense of smell.
10 [0107] The embodiments and examples disclosed herein should be considered to be
exemplary in all respects and not restrictive. The scope of the present disclosure is
indicated by the scope of claims rather than the above description, and is intended to
include the meaning equivalent to the scope of claims and all modifications within the
scope.
15 REFERENCE SIGNS LIST
[0108] 1 Outdoor unit; 2 Indoor unit; 3 Compressor; 4 Condenser; 5 Outdoor blower; 6
Expansion valve; 7 Evaporator; 8 Indoor blower; 9 Liquid pipe; 10 Gas pipe; 11 Shell;
12 Compression mechanism; 13 Electric motor; 14 Inlet pipe; 15 Discharge pipe; 16
Accumulator; 17 Rolling piston; 18 Cylinder; 19 Cylinder chamber; 20 Upper bearing;
20 21 Discharge hole of upper bearing; 22 Muffler space; 23 Discharge muffler; 24
Discharge hole of discharge muffler; 25 Electric motor rotor; 26 Electric motor stator;
27 Oil reservoir part; 28 Driving shaft; 100 Refrigerant circuit

WE CLAIM:
[Claim 1] A refrigeration cycle device comprising: a refrigerant circuit
comprising a compressor, wherein
5 a refrigerant is enclosed in the refrigerant circuit,
the refrigerant contains a hydrocarbon having 1 to 4 carbon atoms and a sulfurbased odorant,
the compressor is filled with a refrigeration oil,
the refrigeration oil contains polyalkylene glycol, and
10 a ratio of a number of oxygen atoms to a number of carbon atoms in a
molecular structure of polyalkylene glycol is 0.50 or less.
[Claim 2] The refrigeration cycle device according to claim 1, wherein a
difference between an HSP distance between polyalkylene glycol and the sulfur-based
15 odorant and an HSP distance between polyalkylene glycol and the refrigerant is -2.0 or
more.
[Claim 3] The refrigeration cycle device according to claim 2, wherein the
difference between the HSP distance between polyalkylene glycol and the sulfur-based
20 odorant and the HSP distance between polyalkylene glycol and the refrigerant is -0.5 or
more.
[Claim 4] The refrigeration cycle device according to any one of claims 1 to 3,
wherein the sulfur-based odorant is at least one selected from the group consisting of
25 mercaptans, sulfides, and thiophenes.
[Claim 5] The refrigeration cycle device according to any one of claims 1 to 4,
wherein the refrigerant is at least one selected from the group consisting of propane,
propylene, and isobutane.
- 29 -
[Claim 6] The refrigeration cycle device according to any one of claims 1 to 5,
wherein
the sulfur-based odorant is tetrahydrothiophene, and
5 the refrigerant is propane.
[Claim 7] The refrigeration cycle device according to any one of claims 1 to 6,
wherein a concentration of the sulfur-based odorant in the refrigerant is 50 ppm by
weight or more and less than 1,100 ppm by weight.