U.S. patent application number 12/920595 was filed with the patent office on 2011-01-20 for refrigeration apparatus.
Invention is credited to Hideki Hara, Hideki Matsuura, Youichi Ohnuma, Kouji Shibaike, Masaru Tanaka.
Application Number | 20110011123 12/920595 |
Document ID | / |
Family ID | 41090654 |
Filed Date | 2011-01-20 |
United States Patent
Application |
20110011123 |
Kind Code |
A1 |
Matsuura; Hideki ; et
al. |
January 20, 2011 |
REFRIGERATION APPARATUS
Abstract
In a refrigeration apparatus including a refrigerant circuit in
which refrigerant represented by Molecular Formula 1:
C.sub.3H.sub.mF.sub.n (note that "m" and "n" are integers equal to
or greater than 1 and equal to or less than 5, and a relationship
represented by an expression m+n=6 is satisfied) and having a
single double bond in a molecular structure, or refrigerant mixture
containing the refrigerant is used, predetermined functional resin
components arranged so as to contact refrigerant of the refrigerant
circuit are made of any of polytetrafluoroethylene, polyphenylene
sulfide, phenolic resin, polyamide resin, chloroprene rubber,
silicone rubber, hydrogenated nitrile rubber, fluorine-containing
rubber, and hydrin rubber.
Inventors: |
Matsuura; Hideki; (Osaka,
JP) ; Tanaka; Masaru; (Osaka, JP) ; Hara;
Hideki; (Osaka, JP) ; Shibaike; Kouji; (Shiga,
JP) ; Ohnuma; Youichi; (Shiga, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
41090654 |
Appl. No.: |
12/920595 |
Filed: |
March 5, 2009 |
PCT Filed: |
March 5, 2009 |
PCT NO: |
PCT/JP2009/001006 |
371 Date: |
September 2, 2010 |
Current U.S.
Class: |
62/468 ;
62/498 |
Current CPC
Class: |
F04C 2210/10 20130101;
F25B 9/002 20130101; C10M 2209/043 20130101; C10N 2020/101
20200501; C09K 2205/126 20130101; C10N 2030/02 20130101; F04B
39/023 20130101; F04C 18/0215 20130101; F04C 2210/263 20130101;
F05C 2225/00 20130101; C10M 2207/2835 20130101; C10M 171/008
20130101; F04C 2210/26 20130101; C09K 5/045 20130101; C10N 2030/41
20200501; C10N 2040/30 20130101; C10M 2209/1033 20130101; C10N
2030/43 20200501; F04C 23/008 20130101; F05C 2225/06 20130101; F04C
2210/1022 20130101; F05C 2225/04 20130101; F05C 2225/02
20130101 |
Class at
Publication: |
62/468 ;
62/498 |
International
Class: |
F25B 43/00 20060101
F25B043/00; F25B 1/00 20060101 F25B001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 18, 2008 |
JP |
2008-070238 |
Claims
1. A refrigeration apparatus, comprising: a refrigerant circuit in
which refrigerant is circulated by a compressor to perform a
refrigeration cycle, wherein, as refrigerant of the refrigerant
circuit, refrigerant represented by Molecular Formula 1:
C.sub.3H.sub.mF.sub.n, where "m" and "n" are integers equal to or
greater than 1 and equal to or less than 5, and a relationship
represented by an expression m+n=6 is satisfied, and having a
single double bond in a molecular structure, or refrigerant mixture
containing the refrigerant is used; and predetermined functional
resin components arranged so as to contact the refrigerant of the
refrigerant circuit are made of any of polytetrafluoroethylene,
polyphenylene sulfide, phenolic resin, polyamide resin, chloroprene
rubber, silicone rubber, hydrogenated nitrile rubber,
fluorine-containing rubber, and hydrin rubber.
2. The refrigeration apparatus of claim 1, wherein the functional
resin components are sliding members provided in predetermined
sliding sections; and the sliding members are made of any of
polytetrafluoroethylene, polyphenylene sulfide, and polyamide
resin.
3. The refrigeration apparatus of claim 1, wherein the functional
resin component is a sealing member for reducing or preventing a
leakage of refrigerant in a predetermined clearance; and the
sealing member is made of any of polytetrafluoroethylene,
polyphenylene sulfide, chloroprene rubber, silicone rubber,
hydrogenated nitrile rubber, fluorine-containing rubber, and hydrin
rubber.
4. The refrigeration apparatus of claim 1, wherein, in the
compressor, refrigerant oil is used, which has a saturated water
amount of equal to or greater than 2000 ppm at a temperature of
30.degree. C. and a relative humidity of 90%.
5. The refrigeration apparatus of claim 4, wherein the refrigerant
oil mainly contains at least one of polyalkylene glycol, polyol
ester, and polyvinyl ether.
6. The refrigeration apparatus of claim 4, wherein the refrigerant
oil has kinetic viscosity of equal to or greater than 30 cSt and
equal to or less than 400 cSt at 40.degree. C., and a fluid point
of equal to or less than -30.degree. C.
7. The refrigeration apparatus of claim 4, wherein the refrigerant
oil has surface tension of equal to or greater than 0.02 N/m and
equal to or less than 0.04 N/m at 20.degree. C.
8. The refrigeration apparatus of claim 7, wherein the refrigerant
oil has a chlorine concentration of equal to or less than 50
ppm.
9. The refrigeration apparatus of claim 4, wherein the refrigerant
oil has a sulfur concentration of equal to or less than 50 ppm.
10. The refrigeration apparatus of claim 4, wherein at least one of
additives which are an acid trapping agent, an extreme pressure
additive, an antioxidizing agent, an oxygen trapping agent, an
antifoam agent, an oiliness agent, and a copper deactivator is
added to the refrigerant oil.
11. The refrigeration apparatus of claim 10, wherein, if a single
type of additive is added to the refrigerant oil, the proportion of
the additive is equal to or greater than 0.01% by mass and equal to
or less than 5% by mass; and if multiple types of additives are
added, the proportion of each additive is equal to or greater than
0.01% by mass and equal to or less than 5% by mass.
12. The refrigeration apparatus of claim 1, wherein the refrigerant
represented by Molecular Formula 1: C.sub.3H.sub.mF.sub.n where "m"
and "n" are the integers equal to or greater than 1 and equal to or
less than 5, and the relationship represented by the expression
m+n=6 is satisfied, and having the single double bond in the
molecular structure is 2, 3, 3, 3-tetrafluoro-1-propene.
13. The refrigeration apparatus of claim 1, wherein the refrigerant
of the refrigerant circuit is refrigerant mixture further
containing difluoromethane.
14. The refrigeration apparatus of claim 1, wherein the refrigerant
of the refrigerant circuit is refrigerant mixture further
containing pentafluoroethane.
Description
TECHNICAL FIELD
[0001] The present invention relates to a refrigeration apparatus
including a refrigerant circuit in which refrigerant is compressed
by a compressor to perform a refrigeration cycle.
BACKGROUND ART
[0002] Conventionally, a refrigeration apparatus including a
refrigerant circuit in which a refrigeration cycle is performed has
been broadly applied to an air conditioning system, a hot-water
supply system, etc.
[0003] Patent Document 1 discloses the refrigeration apparatus of
this type. The refrigeration apparatus includes a refrigerant
circuit in which a compressor, a condenser, an expansion valve, and
an evaporator are connected together to perform a refrigeration
cycle. In the refrigerant circuit, refrigerant compressed by the
compressor is condensed by releasing heat to air in the condenser.
The pressure of the refrigerant condensed in the condenser is
reduced by the expansion valve, and then such refrigerant is
evaporated in the evaporator. The evaporated refrigerant is sucked
into and recompressed in the compressor.
[0004] Refrigerant represented by Molecular Formula 1:
C.sub.3H.sub.mF.sub.n (note that "m" and "n" are integers equal to
or greater than 1 and equal to or less than 5, and a relationship
represented by an expression m+n=6 is satisfied) and having a
single double bond in a molecular structure is used for the
refrigerant circuit of Patent Document 1. It has been known that
such refrigerant does not contain chlorine and bromine atoms, and
has a small influence on destruction of the ozone layer.
Citation List
Patent Document
[0005] PATENT DOCUMENT 1: Japanese Patent Application No.
04-110388
SUMMARY OF THE INVENTION
Technical Problem
[0006] The refrigerant disclosed in Patent Document 1 has a
relatively-unstable molecular structure such as the structure
having the double bond. Thus, the refrigerant may be deteriorated
due to a long-term refrigeration cycle, resulting in generation of
impurities etc. When generating such impurities, e.g., functional
resin components such as a sliding member of a movable scroll of
the compressor and a sealing member are likely to be deteriorated
due to the influence of the impurities. Consequently, there is a
possibility that durability and reliability of such functional
components are degraded.
[0007] The present invention has been made in view of the
foregoing, and it is an object of the present invention to reduce
deterioration of predetermined functional resin component(s)
arranged so as to contact refrigerant in a refrigeration apparatus
including a refrigerant circuit for which single component
refrigerant containing refrigerant represented by Molecular Formula
1: C.sub.3H.sub.mF.sub.n (note that "m" and "n" are integers equal
to or greater than 1 and equal to or less than 5, and a
relationship represented by an expression m+n=6 is satisfied) and
having a single double bond in a molecular structure, or
refrigerant mixture containing such refrigerant is used.
Solution to the Problem
[0008] A first aspect of the invention is intended for a
refrigeration apparatus including a refrigerant circuit (10) in
which refrigerant is circulated by a compressor (30) to perform a
refrigeration cycle; in which, as refrigerant of the refrigerant
circuit (10), refrigerant represented by Molecular Formula 1:
C.sub.3H.sub.mF.sub.n (note that "m" and "n" are integers equal to
or greater than 1 and equal to or less than 5, and a relationship
represented by an expression m+n=6 is satisfied) and having a
single double bond in a molecular structure, or refrigerant mixture
containing the refrigerant is used. In the refrigeration apparatus,
predetermined functional resin components (61, 62, 63, 64, 65)
arranged so as to contact the refrigerant of the refrigerant
circuit (10) are made of any of polytetrafluoroethylene,
polyphenylene sulfide, phenolic resin, polyamide resin, chloroprene
rubber, silicone rubber, hydrogenated nitrile rubber,
fluorine-containing rubber, and hydrin rubber.
[0009] In the refrigeration apparatus of the first aspect of the
invention, as the refrigeration of the refrigerant circuit (10),
the refrigerant represented by Molecular Formula 1 and having the
single double bond in the molecular structure, or the refrigerant
mixture containing such refrigerant is used. The refrigerant is
compressed by the compressor (30) to perform the refrigeration
cycle in the refrigerant circuit (10).
[0010] The predetermined functional resin components (61, 62, 63,
64, 65) are arranged so as to contact the refrigerant of the
refrigerant circuit (10). The functional resin components (61, 62,
63, 64, 65) are made of any of polytetrafluoroethylene,
polyphenylene sulfide, phenolic resin, polyamide resin, chloroprene
rubber, silicone rubber, hydrogenated nitrile rubber,
fluorine-containing rubber, and hydrin rubber. Such resin materials
have relatively-high stability to impurities generated from
refrigerant. Consequently, deterioration of the functional resin
components due to the generation of impurities is reduced.
[0011] A second aspect of the invention is intended for the
refrigeration apparatus of the first aspect of the invention, in
which the functional resin component is a sliding member (61-64)
provided in a predetermined sliding section, and the sliding member
(61-64) is made of any of polytetrafluoroethylene, polyphenylene
sulfide, and polyamide resin.
[0012] In the second aspect of the invention, the sliding member
(61-64) provided in the sliding section is the functional resin
component. The sliding member (61-64) is made of any of
polytetrafluoroethylene, polyphenylene sulfide, and polyamide
resin. Thus, denaturalization/deterioration of the sliding member
(61-64) due to impurities generated from refrigerant is
reduced.
[0013] A third aspect of the invention is intended for the
refrigeration apparatus of the first aspect of the invention, in
which the functional resin component is a sealing member (65) for
reducing or preventing a leakage of refrigerant in a predetermined
clearance, and the sealing member (65) is made of any of
polytetrafluoroethylene, polyphenylene sulfide, chloroprene rubber,
silicone rubber, hydrogenated nitrile rubber, fluorine-containing
rubber, and hydrin rubber.
[0014] In the third aspect of the invention, the sealing member
(65) for reducing or preventing the leakage of refrigerant in the
predetermined clearance is the functional resin component. The
sealing member (65) is made of any of polyphenylene sulfide,
chloroprene rubber, silicone rubber, hydrogenated nitrile rubber,
fluorine-containing rubber, and hydrin rubber. Thus,
denaturalization/deterioration of the sealing member (65) due to
impurities generated from refrigerant is reduced.
[0015] A fourth aspect of the invention is intended for the
refrigeration apparatus of any one of the first to third aspects of
the invention, in which, in the compressor (30), refrigerant oil is
used, which has a saturated water amount of equal to or greater
than 2000 ppm at a temperature of 30.degree. C. and a relative
humidity of 90%.
[0016] In the fourth aspect of the invention, as the refrigerant
oil of the compressor (30), the refrigerant oil is used, which has
the saturated water amount of equal to or greater than 2000 ppm at
the temperature of 30.degree. C. and the relative humidity of 90%.
That is, in the present invention, refrigerant oil having
relatively-high hygroscopic properties is used. This allows the
refrigerant oil to trap moisture in refrigerant. Consequently,
deterioration of refrigerant due to moisture is reduced.
[0017] A fifth aspect of the invention is intended for the
refrigeration apparatus of the fourth aspect of the invention, in
which the refrigerant oil mainly contains at least one of
polyalkylene glycol, polyol ester, and polyvinyl ether.
[0018] In the fifth aspect of the invention, as the refrigerant
oil, the refrigerant oil mainly containing at least one of
polyalkylene glycol, polyol ester, and polyvinyl ether is used.
Such refrigerant oils have compatibility with the refrigerant
represented by Molecular Formula 1 and having the single double
bond in the molecular structure, and therefore such refrigerant is
easily dissolved with the refrigerant oil.
[0019] When generating impurities due to the deterioration of
refrigerant as described above, the refrigerant oil of the present
invention may be also deteriorated due to such impurities. Thus,
impurities are further generated due to the deterioration of the
refrigerant oil, and therefore the functional resin components (61,
62, 63, 64, 65) are likely to be deteriorated due to impurities
derived from the refrigerant oil. However, in the present
invention, any of polytetrafluoroethylene, polyphenylene sulfide,
phenolic resin, polyamide resin, chloroprene rubber, silicone
rubber, hydrogenated nitrile rubber, fluorine-containing rubber,
and hydrin rubber is used for the functional resin components (61,
62, 63, 64, 65), thereby avoiding the deterioration of the
functional resin components (61, 62, 63, 64, 65) due to impurities
generated from the refrigerant oil.
[0020] A sixth aspect of the invention is intended for the
refrigeration apparatus of the fourth or fifth aspect of the
invention, in which the refrigerant oil has kinetic viscosity of
equal to or greater than 30 cSt and equal to or less than 400 cSt
at 40.degree. C., and a fluid point of equal to or less than
-30.degree. C.
[0021] In the sixth aspect of the invention, the kinetic viscosity
of the refrigerant oil is equal to or greater than 30 cSt at
40.degree. C., and therefore insufficient kinetic viscosity does
not result in insufficient oil film strength. Thus, lubrication in
the sliding sections is ensured. In addition, the fluid point of
the refrigerant oil is equal to or less than -30.degree. C.,
thereby ensuring fluidity of the refrigerant oil even in a
low-temperature section of the refrigerant circuit (10).
[0022] A seventh aspect of the invention is intended for the
refrigeration apparatus of any one of the first to sixth aspects of
the invention, in which the refrigerant oil has surface tension of
equal to or greater than 0.02 N/m and equal to or less than 0.04
N/m at 20.degree. C.
[0023] In the seventh aspect of the invention, the surface tension
of the refrigerant oil is equal to or greater than 0.02 N/m and
equal to or less than 0.04 N/m at 20.degree. C. If the surface
tension of the refrigerant oil is extremely low, small oil droplets
of the refrigerant oil tend to be produced in gaseous refrigerant
inside the compressor (30), and a relatively large amount of the
refrigerant oil is discharged from the compressor (30) together
with refrigerant. Thus, there is a possibility to cause excessive
oil discharge from the compressor (30). Conversely, if the surface
tension of the refrigerant oil is extremely high, large oil
droplets of the refrigerant oil discharged from the compressor (30)
tend to be produced in the refrigerant circuit (10). Thus, the
refrigerant oil discharged from the compressor (30) is difficult to
be pushed to flow by refrigerant, and difficult to return to the
compressor (30). Consequently, in such a state, there is the
possibility to case the excessive oil discharge from the compressor
(30).
[0024] As described above, in the present invention, the surface
tension of the refrigerant oil is equal to or greater than 0.02 N/m
and equal to or less than 0.04 N/m at 20.degree. C. Thus, the size
of the oil droplet falls within a suitable range, thereby avoiding
the excessive oil discharge.
[0025] An eighth aspect of the invention is intended for the
refrigeration apparatus of any one of the fourth to seventh aspects
of the invention, in which the refrigerant oil has a chlorine
concentration of equal to or less than 50 ppm.
[0026] In the eighth aspect of the invention, the chlorine
concentration of the refrigerant oil is equal to or less than 50
ppm, thereby reducing acceleration of deterioration of refrigerant
due to chlorine. This reduces the generation of impurities, and
improves durability of the functional resin components (61, 62, 63,
64, 65).
[0027] A ninth aspect of the invention is intended for the
refrigeration apparatus of any one of the fourth to eighth aspects
of the invention, in which the refrigerant oil has a sulfur
concentration of equal to or less than 50 ppm.
[0028] In the ninth aspect of the invention, the sulfur
concentration of the refrigerant oil is equal to or less than 50
ppm, thereby reducing deterioration of refrigerant due to sulfur.
This reduces the generation of impurities, and improves the
durability of the functional resin components (61, 62, 63, 64,
65).
[0029] A tenth aspect of the invention is intended for the
refrigeration apparatus of any one of the fourth to ninth aspects
of the invention, in which at least one of additives which are an
acid trapping agent, an extreme pressure additive, an antioxidizing
agent, an oxygen trapping agent, an antifoam agent, an oiliness
agent, and a copper deactivator is added to the refrigerant
oil.
[0030] In the tenth aspect of the invention, at least one of the
additives which are the acid trapping agent, the extreme pressure
additive, the antioxidizing agent, the oxygen trapping agent, the
antifoam agent, the oiliness agent, and the copper deactivator is
contained in the refrigerant oil. This stabilizes the refrigerant
oil and refrigerant, and reduces the generation of impurities
etc.
[0031] An eleventh aspect of the invention is intended for the
refrigeration apparatus of the tenth aspect of the invention, in
which, if a single type of additive is added to the refrigerant
oil, the proportion of the additive is equal to or greater than
0.01% by mass and equal to or less than 5% by mass; and if multiple
types of additives are added, the proportion of each additive is
equal to or greater than 0.01% by mass and equal to or less than 5%
by mass.
[0032] In the eleventh aspect of the invention, if the single type
of additive is added to the refrigerant oil, the proportion of the
additive in the refrigerant oil is equal to or greater than 0.01%
by mass and equal to or less than 5% by mass. If the multiple types
of additives are added to the refrigerant oil, the proportion of
each additive in the refrigerant oil is equal to or greater than
0.01% by mass and equal to or less than 5% by mass.
[0033] A twelfth aspect of the invention is intended for the
refrigeration apparatus of any one of the first to eleventh aspects
of the invention, in which the refrigerant represented by Molecular
Formula 1: C.sub.3H.sub.mF.sub.n (note that "m" and "n" are the
integers equal to or greater than 1 and equal to or less than 5,
and the relationship represented by the expression m+n=6 is
satisfied) and having the single double bond in the molecular
structure is 2, 3, 3, 3-tetrafluoro-1-propene.
[0034] In the twelfth aspect of the invention, as the refrigerant
of the refrigerant circuit (10), the single component refrigerant
which is 2, 3, 3, 3-tetrafluoro-1-propene, or the refrigerant
mixture containing 2, 3, 3, 3-tetrafluoro-1-propene is used.
[0035] A thirteenth aspect of the invention is intended for the
refrigeration apparatus of any one of the first to twelfth aspects
of the invention, in which the refrigerant of the refrigerant
circuit (10) is refrigerant mixture further containing
difluoromethane.
[0036] In the thirteenth aspect of the invention, as the
refrigerant of the refrigerant circuit (10), the refrigerant
mixture is used, which contains the refrigerant represented by
Molecular Formula 1 and having the single double bond in the
molecular structure, and difluoromethane. The refrigerant
represented by Molecular Formula 1 and having the single double
bond in the molecular structure is so-called "low-pressure
refrigerant." Thus, if, e.g., single component refrigerant of the
refrigerant represented by Molecular Formula 1 and having the
single double bond in the molecular structure is used, an influence
of a pressure loss of refrigerant on an operational efficiency of
the refrigeration apparatus is relatively large, thereby degrading
an actual operational efficiency as compared to a theoretical
operational efficiency. In the present invention, difluoromethane
which is so-called "high-pressure refrigerant" is added to the
refrigerant represented by Molecular Formula 1 and having the
single double bond in the molecular structure.
[0037] A fourteenth aspect of the invention is intended for the
refrigeration apparatus of any one of the first to thirteenth
aspects of the invention, in which the refrigerant of the
refrigerant circuit (10) is refrigerant mixture further containing
pentafluoroethane.
[0038] In the fourteenth aspect of the invention, as the
refrigerant of the refrigerant circuit (10), the refrigerant
mixture is used, which contains the refrigerant represented by
Molecular Formula 1 and having the single double bond in the
molecular structure, and pentafluoroethane. The refrigerant
represented by Molecular Formula 1 and having the single double
bond in the molecular structure is low flammable refrigerant, but
there is no possibility that such refrigerant does not catch fire.
In the present invention, pentafluoroethane which is non-flammable
refrigerant is added to the refrigerant represented by Molecular
Formula 1 and having the single double bond in the molecular
structure.
ADVANTAGES OF THE INVENTION
[0039] In the present invention, as the refrigerant of the
refrigerant circuit (10), the refrigerant represented by Molecular
Formula 1: C.sub.3H.sub.mF.sub.n (note that "m" and "n" are the
integers equal to or greater than 1 and equal to or less than 5,
and the relationship represented by the expression m+n=6 is
satisfied) and having the single double bond in the molecular
structure, or the refrigerant mixture containing the refrigerant is
used. Thus, the refrigeration apparatus having a higher theoretical
coefficient of performance (COP) of the refrigeration cycle can be
provided.
[0040] The refrigerant has a relatively-unstable molecular
structure due to, e.g., the structure having the double bond, and
refrigerant is likely to be deteriorated to generate impurities
etc. Thus, there is a possibility that the functional resin
components (61, 62, 63, 64,65) of the refrigeration apparatus are
chemically/physically denatured and deteriorated due to an
influence of such impurities. However, the functional resin
components (61, 62, 63, 64,65) of the present invention are made of
material having the relatively-high stability to the impurities of
refrigerant, i.e., any of polytetrafluoroethylene, polyphenylene
sulfide, phenolic resin, polyamide resin, chloroprene rubber,
silicone rubber, hydrogenated nitrile rubber, fluorine-containing
rubber, and hydrin rubber. Thus, the chemical/physical
denaturalization of the functional resin components (61, 62, 63,
64,65) due to the influence of the impurities is avoided.
Consequently, in the functional resin components, a desired
durability can be ensured.
[0041] In the second aspect of the invention, the sliding members
(61, 62, 63, 64) which are the functional resin components are made
of any of polytetrafluoroethylene, polyphenylene sulfide, and
polyamide resin. Thus, the deterioration of the sliding members
(61, 62, 63, 64) due to impurities generated from refrigerant can
be avoided. Consequently, the durability of the sliding members
(61, 62, 63, 64) can be improved, thereby obtaining desired sliding
properties/abrasion resistance in the sliding members (61, 62, 63,
64).
[0042] In the third aspect of the invention, the sealing member
(65) which is the functional resin component is made of any of
polytetrafluoroethylene, polyphenylene sulfide, chloroprene rubber,
silicone rubber, hydrogenated nitrile rubber, fluorine-containing
rubber, and hydrin rubber. Thus, the deterioration of the sealing
member (65) due to impurities generated from refrigerant can be
avoided. Consequently, the durability of the sealing member (65) is
improved, thereby obtaining desired sealing properties in the
sealing member (65).
[0043] In the fourth aspect of the invention, the refrigerant oil
is used, which has the saturated water amount of equal to or
greater than 2000 ppm at the temperature of 30.degree. C. and the
relative humidity of 90%. Thus, moisture in refrigerant can be
trapped by the refrigerant oil. This reduces or prevents the
deterioration of refrigerant due to an influence of moisture.
[0044] The refrigerant oil of the fifth aspect of the invention
mainly contains at least one of polyalkylene glycol, polyol ester,
and polyvinyl ether. This allows refrigerant and the refrigerant
oil to easily dissolve each other. Thus, even if the refrigerant
oil flows into the refrigerant circuit (10), the refrigerant oil is
dissolved with refrigerant, and is easily sent back to the
compressor (30). As a result, the excessive oil discharge from the
compressor (30) can be reduced, thereby avoiding a shortage of the
refrigerant oil and inadequate lubrication in the compressor (30).
Consequently, reliability of the compressor (30) can be
improved.
[0045] In particular, the refrigerant oil of the sixth aspect of
the invention has the kinetic viscosity of equal to or greater than
30 cSt and equal to or less than 400 cSt at 40.degree. C., thereby
ensuring adequate lubrication in the sliding sections. In addition,
in the present invention, the fluid point is equal to or less than
-30.degree. C., thereby ensuring the fluidity of the refrigerant
oil even in a relatively-low-temperature section.
[0046] The refrigerant oil of the seventh aspect of the invention
has the surface tension of equal to or greater than 0.02 N/m and
equal to or less than 0.04 N/m at 20.degree. C. Thus, a large
amount of the refrigerant oil is not discharged from the compressor
(30), or the refrigerant oil discharged from the compressor (30) is
not hard to return to the compressor (30). Consequently, the
excessive oil discharge from the compressor (30) can be reduced,
thereby reducing or preventing inadequate lubrication in the
sliding sections of the compression mechanism (82).
[0047] The refrigerant oil of the eighth aspect of the invention
has the chlorine concentration of equal to or less than 50 ppm,
thereby reducing or preventing the acceleration of the
deterioration of refrigerant due to chlorine. Consequently, the
durability of the functional resin components (61, 62, 63, 64, 65)
can be further improved. In addition, the refrigerant oil of the
ninth aspect of the invention has the sulfur concentration of equal
to or less than 50 ppm, thereby reducing or preventing the
acceleration of the deterioration of refrigerant due to sulfur.
Consequently, the durability of the functional resin components
(61, 62, 63, 64, 65) can be further improved.
[0048] At least one of the six additives which are the acid
trapping agent, the extreme pressure additive, the antioxidizing
agent, the antifoam agent, the oiliness agent, and the copper
deactivator is added to the refrigerant oil of the tenth or
eleventh aspect of the invention. This stabilizes refrigerant or
the refrigerant oil, thereby reducing the generation of impurities.
Consequently, the durability/reliability of the functional resin
components (61, 62, 63, 64, 65) can be further improved.
[0049] In the twelfth aspect of the invention, the refrigerant
represented by Molecular Formula 1 and having the single double
bond in the molecular structure is 2, 3, 3,
3-tetrafluoro-1-propene, thereby improving the COP of the
refrigeration cycle.
[0050] In the thirteenth aspect of the invention, difluoromethane
which is so-called "high-pressure refrigerant" is added to the
refrigerant represented by Molecular Formula 1 and having the
single double bond in the molecular structure. Thus, the influence
of the pressure loss of refrigerant on the operational efficiency
of the refrigeration apparatus can be reduced, thereby improving
the actual operational efficiency of the refrigeration
apparatus.
[0051] In the fourteenth aspect of the invention, pentafluoroethane
which is non-flammable refrigerant is added to the refrigerant
represented by Molecular Formula 1 and having the single double
bond in the molecular structure. Thus, the refrigerant of the
refrigerant circuit (10) hardly catches fire, thereby improving
reliability of the refrigeration apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
[0052] [FIG. 1] FIG. 1 is a schematic configuration diagram of a
refrigeration apparatus of an embodiment.
[0053] [FIG. 2] FIG. 2 is a longitudinal sectional view of a
compressor of the embodiment.
[0054] [FIG. 3] FIG. 3 is a cross sectional view of the compressor
of the embodiment.
[0055] [FIG. 4] FIG. 4 is a longitudinal sectional view of a
compressor of a third variation of the embodiment.
DESCRIPTION OF REFERENCE CHARACTERS
[0056] 10 Refrigerant Circuit [0057] 20 Air Conditioning System
(Refrigeration Apparatus) [0058] 30 Compressor [0059] 61 Upper
Bearing (Sliding Member, Functional Resin Component) [0060] 62
Intermediate Bearing (Sliding Member, Functional Resin Component)
[0061] 63 Lower Bearing (Sliding Member, Functional Resin
Component) [0062] 64 Thrust Bearing (Sliding Member, Functional
Resin Component) [0063] 65 Seal Ring (Sealing Member)
DESCRIPTION OF EMBODIMENTS
[0064] Embodiments of the present invention will be described in
detail hereinafter with reference to the drawings.
[0065] The present embodiment is intended for an air conditioning
system (20) including a refrigeration apparatus (20) of the present
invention. As illustrated in FIG. 1, the air conditioning system
(20) of the present embodiment includes an outdoor unit (22) and
three indoor units (23a, 23b, 23c). The number of the indoor units
(23) is set forth merely for purposes of examples.
[0066] The air conditioning system (20) includes a refrigerant
circuit (10) filled with refrigerant to perform a refrigeration
cycle. The refrigerant circuit (10) includes an outdoor circuit (9)
accommodated in the outdoor unit (22); and an indoor circuit (17a,
17b, 17c) accommodated in each of the indoor units (23). The indoor
circuits (17a, 17b, 17c) are connected to the outdoor circuit (9)
through a fluid-side communication pipe (18) and a gas-side
communication pipe (19). The indoor circuits (17a, 17b, 17c) are
connected to each other in parallel.
[0067] The refrigerant circuit (10) of the present embodiment is
filled with single component refrigerant of 2, 3, 3,
3-tetrafluoro-1-propene (hereinafter referred to as "HFO-1234yf")
as refrigerant. Note that a chemical formula of the HFO-1234yf is
represented by an expression CF.sub.3-CF=CH.sub.2.
[0068] <Configuration of Outdoor Circuit>
[0069] The outdoor circuit (9) includes a compressor (30), an
outdoor heat exchanger (11), an outdoor expansion valve (12), and a
four-way switching valve (13).
[0070] The compressor (30) is, e.g., an inverter compressor with
variable operational capacity. Electric power is supplied to the
compressor (30) through an inverter. A discharge side of the
compressor (30) is connected to a second port (P2) of the four-way
switching valve (13), and a suction side of the compressor (30) is
connected to a first port (P1) of the four-way switching valve
(13). The compressor (30) will be described in detail later.
[0071] The outdoor heat exchanger (11) is a cross-fin type
fin-and-tube heat exchanger. An outdoor fan (14) is provided near
the outdoor heat exchanger (11). In the outdoor heat exchanger
(11), heat is exchanged between outdoor air and refrigerant. One
end of the outdoor heat exchanger (11) is connected to a third port
(P3) of the four-way switching valve (13), and the other end is
connected to the outdoor expansion valve (12). A fourth port (P4)
of the four-way switching valve (13) is connected to the gas-side
communication pipe (19).
[0072] The outdoor expansion valve (12) is provided between the
outdoor heat exchanger (11) and a fluid-side end of the outdoor
circuit (9). The outdoor expansion valve (12) is an electric
expansion valve with variable opening.
[0073] The four-way switching valve (13) is switchable between a
first state in which the first port (P1) communicates with the
fourth port (P4), and the second port (P2) communicates with the
third port (P3) (state indicated by a solid line in FIG. 1); and a
second state in which the first port (P1) communicates with the
third port (P3), and the second port (P2) communicates with the
fourth port (P4) (state indicated by a dashed line in FIG. 1).
[0074] <Configuration of Indoor Circuit>
[0075] In each of the indoor circuits (17), an indoor heat
exchanger (15a, 15b, 15c) and an indoor expansion valve (16a, 16b,
16c) are provided in the order from a gas-side end thereof toward a
fluid-side end.
[0076] The indoor heat exchanger (15) is a cross-fin type
fin-and-tube heat exchanger. An indoor fan (21) is provided near
the indoor heat exchanger (15). In the indoor heat exchanger (15),
heat is exchanged between room air and refrigerant. In addition,
the indoor expansion valve (16) is an electric expansion valve with
variable opening.
[0077] <Configuration of Compressor>
[0078] The compressor (30) is, e.g., a hermetic high-pressure dome
scroll-type compressor. A configuration of the compressor (30) will
be described with reference to FIGS. 2 and 3.
[0079] The compressor (30) includes a casing (70) which is an
upright hermetic container. An electric motor (85) and a
compression mechanism (82) are arranged inside the casing (70) in
the order from the bottom to the top.
[0080] The electric motor (85) includes a stator (83) and a rotor
(84). The stator (83) is fixed to a body section of the casing
(70). On the other hand, the rotor (84) is arranged on an inner
side with respect to the stator (83), and is connected to a crank
shaft (90). The crank shaft (90) is supported by a lower bearing
member (60) arranged near an oil sump of the casing (70).
[0081] The compression mechanism (82) includes a movable scroll
(76) and a fixed scroll (75), and serves as a scroll-type
compression mechanism. The movable scroll (76) includes an
approximately discoid movable-side end plate (76b) and a spiral
movable-side wrap (76a). The movable-side wrap (76a) is vertically
arranged on a front surface (upper surface) of the movable-side end
plate (76b). A cylindrical protrusion (76c) to which an eccentric
section of the crank shaft (90) is inserted is vertically arranged
on a back surface (lower surface) of the movable-side end plate
(76b). The movable scroll (76) is supported by a housing (77)
arranged below the movable scroll (76), through an Oldham's ring
(79). On the other hand, the fixed scroll (75) includes an
approximately discoid fixed-side end plate (75b) and a spiral
fixed-side wrap (75a). The fixed-side wrap (75a) is vertically
arranged on a front surface (lower surface) of the fixed-side end
plate (75b). In the compression mechanism (82), the fixed-side wrap
(75a) is engaged with the movable-side wrap (76a), thereby forming
a plurality of compression chambers (73) between contact sections
of both wraps (75a, 76a).
[0082] In the compressor (30) of the present embodiment, a
so-called "asymmetrical spiral structure" is employed, and the
fixed-side wrap (75a) and the movable-side wrap (76a) have the
different number of turns (the different length of the spiral wrap)
from each other. The plurality of compression chambers (73)
includes a first compression chamber (73a) defined between an inner
circumferential surface of the fixed-side wrap (75a) and an outer
circumferential surface of the movable-side wrap (76a); and a
second compression chamber (73b) defined between an outer
circumferential surface of the fixed-side wrap (75a) and an inner
circumferential surface of the movable-side wrap (76a).
[0083] In the compression mechanism (82), a suction port (98) is
formed in an outer edge section of the fixed scroll (75). A suction
pipe (57) penetrating a top section of the casing (70) is connected
to the suction port (98). The suction port (98) intermittently
communicates with each of the first compression chamber (73a) and
the second compression chamber (73b) in response to orbital motion
of the movable scroll (76). In addition, a suction check valve (not
shown in the figure) for stopping refrigerant from flowing back
from the compression chamber (73) to the suction pipe (57) is
provided in the suction port (98).
[0084] In the compression mechanism (82), a discharge port (93) is
formed in a center section of the fixed-side end plate (75b). The
discharge port (93) intermittently communicates with each of the
first compression chamber (73a) and the second compression chamber
(73b) in response to the orbital motion of the movable scroll (76).
The discharge port (93) opens to a muffler space (96) formed above
the fixed scroll (75).
[0085] The casing (70) is divided into an upper suction space (101)
and a lower discharge space (100) by the discoid housing (77). The
suction space (101) communicates with the suction port (98) through
a communication port which is not shown in the figure. The
discharge space (100) communicates with the muffler space (96)
through a communication path (103) formed through the fixed scroll
(75) and the housing (77). Refrigerant discharged through the
discharge port (93) flows into the discharge space (100) through
the muffler space (96) during an operation, and therefore the
discharge space (100) becomes a high-pressure space filled with
refrigerant compressed in the compression mechanism (82). A
discharge pipe (56) penetrating the body section of the casing (70)
opens to the discharge space (100).
[0086] In the casing (70) of the compressor (30) of the present
embodiment, insulating coating material of windings of the stator
(83), insulating films, and sealing material of the compression
mechanism (82) are used as components made of organic material. For
such components, material is used, which is not physically or
chemically denatured by refrigerant even if the components contact
high-temperature high-pressure refrigerant, and which particularly
has solvent resistance, extraction resistance, thermal/chemical
stability, and foaming resistance.
[0087] Specifically, for the insulating coating material of the
windings of the stator (83), any of the following is used:
polyvinyl formal; polyester; THEIC modified polyester; polyamide;
polyamide imide; polyester imide; and polyester amide imide. The
double coated wires in which an upper layer is made of polyamide
imide, and a lower layer is made of polyester imide are preferable.
Enamel coating having a glass-transition temperature of equal to or
greater than 120.degree. C. may be used other than the
above-described materials.
[0088] In addition, for the insulating film, any of the following
is used: polyethylene terephthalate (PET); polyethylene naphthalate
(PEN); polyphenylene sulfide (PPS); and polybutylene terephthalate
(PBT). A foaming film made of the same foaming material as that of
refrigerant of the refrigeration cycle may be used. For insulating
material for holding windings such as insulators, polyether ether
ketone (PEEK) or liquid crystal polymer (LCP) is used. Epoxy resin
is used for varnish.
[0089] The oil sump in which refrigerant oil is stored is formed in
a bottom section of the casing (70). A first oil supply path (104)
opening to the oil sump is formed inside the crank shaft (90). A
second oil supply path (105) connected to the first oil supply path
(104) is formed in the movable-side end plate (76b). In the
compressor (30), refrigerant oil in the oil sump is supplied to the
low-pressure-side compression chamber (73) through the first oil
supply path (104) and the second oil supply path (105).
[0090] Structural resin components arranged so as to contact
refrigerant and refrigerant oil are provided in the compressor
(30). In the compressor (30) of the present embodiment, an upper
bearing (61), an intermediate bearing (62), a lower bearing (63),
and a thrust bearing (64) are provided as the structural resin
components.
[0091] The upper bearing (61) is formed in a sliding section
between the eccentric section at an upper end of the crank shaft
(90) and the protrusion (76c) of the movable scroll (76). The
intermediate bearing (62) is formed in a sliding section between a
large-diameter section of the crank shaft (90) and an inner
circumferential surface of a through-hole of the housing (77). The
lower bearing (63) is fondled in a sliding section between a lower
end section of the crank shaft (90) and an inner circumferential
surface of a through-hole of the lower bearing member (60). The
upper bearing (61), the intermediate bearing (62), and the lower
bearing (63) serve as so-called "journal bearings." The thrust
bearing (64) is formed in a sliding section between the back
surface of the movable-side end plate (76b) of the movable scroll
(76) and a support section of the housing (77).
[0092] Each of the bearings (61, 62, 63, 64) which are the
functional resin components serves as a sliding member. The bearing
(61, 62, 63, 64) serving as the sliding member is made of any of
polytetrafluoroethylene (PTFE), polyphenylene sulfide, and
polyamide resin.
[0093] <Refrigerant Oil>
[0094] In the present embodiment, refrigerant oil mainly containing
at least one of three base oils which are polyalkylene glycol,
polyol ester, and polyvinyl ether may be used for the compressor
(30). For example, for refrigerant oil of the present embodiment,
refrigerant oil mainly containing only polyvinyl ether of the three
base oils is used.
[0095] For the refrigerant oil of the present embodiment,
refrigerant oil mainly containing polyvinyl ether having a building
block represented by General Expression (I) is used. Among
polyvinyl ethers, polyvinyl ether with such a structure has
excellent compatibility with the refrigerant represented by
Molecular Formula 1 and having the single double bond in the
molecular structure.
##STR00001##
[0096] In General Expression (I), symbols "R1," "R2," and "R3"
represent a hydrocarbon group in which the hydrogen or carbon
number is equal to or greater than 1 and equal to or less than 8.
The symbols "R1," "R2," and "R3" may be the same or may be
different from each other. In addition, in General Expression (I),
the symbol "R4" has a composition ratio at which an alkyl group
with the carbon number of 1 or 2 is equal to or greater than 40%
and equal to or less than 100%, and an alkyl group with the carbon
number of 3 or 4 is equal to or greater than 0% and equal to or
less than 60%, in each of building blocks.
[0097] The refrigerant oil has kinetic viscosity of equal to or
greater than 30 cSt and equal to or less than 400 cSt at 40.degree.
C.; a fluid point of equal to or less than -30.degree. C.; surface
tension of equal to or greater than 0.02 N/m and equal to or less
than 0.04 N/m at 20.degree. C.; and density of equal to or greater
than 0.8 g/cm.sup.3 and equal to or less than 1.8 g/cm.sup.3 at
15.degree. C. In addition, the refrigerant oil has a saturated
water amount of equal to or greater than 2000 ppm at a temperature
of 30.degree. C. and a relative humidity of 90%, and its aniline
point falls within a predetermined value range. The "aniline point"
means a value representing solubility of, e.g., hydrocarbon
solvent, and represents a temperature when a sample (refrigerant
oil in the present embodiment) is cooled by mixing it with the
equal volume of aniline, and the sample and the aniline no longer
dissolve each other to turn them cloudy (specified by JIS K 2256).
Note that such a value is a value of the refrigerant oil itself in
a state in which refrigerant is not dissolved. In this respect, the
same is true for refrigerant oil described in a first variation, a
second variation, and other embodiments which will be described
later.
[0098] In the present embodiment, polyvinyl ether which is the main
component of the refrigerant oil has compatibility with the
HFO-1234yf. The kinetic viscosity of the refrigerant oil is equal
to or less than 400 cSt at 40.degree. C. Thus, the HFO-1234yf is
dissolved with the refrigerant oil to some extent. The fluid point
of the refrigerant oil is equal to or less than -30.degree. C.,
thereby ensuring fluidity of the refrigerant oil even in a
low-temperature section of the refrigerant circuit (10). The
surface tension is equal to or less than 0.04 N/m at 20.degree. C.,
and thus, the refrigerant oil discharged from the compressor (30)
is less likely to produce large oil droplets, which are difficult
to be pushed to flow by refrigerant. Thus, the refrigerant oil
discharged from the compressor (30) is dissolved with the
HFO-1234yf, and then is returned to the compressor (30) together
with the HFO-1234yf.
[0099] The kinetic viscosity of the refrigerant oil is equal to or
greater than 30 cSt at 40.degree. C., and therefore the
extremely-low kinetic viscosity does not result in insufficient oil
film strength. Consequently, lubricity can be ensured. In addition,
the surface tension is equal to or greater than 0.02 N/m at
20.degree. C., and therefore small oil droplets are less likely to
be produced in gaseous refrigerant inside the compressor (30).
Thus, a large amount of the refrigerant oil is not discharged from
the compressor (30). This ensures a sufficient storage amount of
the refrigerant oil in the compressor (30).
[0100] The saturated water amount of the refrigerant oil is equal
to or greater than 2000 ppm at the temperature of 30.degree. C. and
the relative humidity of 90%, resulting in relatively-high
hygroscopic properties of the refrigerant oil. This allows the
refrigerant oil to trap a certain amount of moisture in the
HFO-1234yf. The HFO-1234yf has a molecular structure which tends to
be altered/deteriorated due to an influence of contained moisture.
Thus, a hygroscopic effect of the refrigerant oil can reduce such
deterioration.
[0101] Further, the value range of the aniline point of the
refrigerant oil may be set considering compatibility with the
functional resin components. By setting the aniline point in this
manner, e.g., compatibility of the bearings (61, 62, 63, 64)
serving as the functional resin components, with the refrigerant
oil is improved. Specifically, if the aniline point is extremely
low, the refrigerant oil tends to penetrate the bearings (61, 62,
63, 64), and therefore the bearings (61, 62, 63, 64) tend to
expand. On the other hand, if the aniline point is extremely high,
the refrigerant oil is less likely to penetrate the bearings (61,
62, 63, 64), and therefore the bearings (61, 62, 63, 64) tend to
contract. The aniline point of the refrigerant oil is set within
the predetermined value range, thereby reducing or preventing the
expansion/contraction deformation of the bearings (61, 62, 63, 64).
In such a state, when causing the expansion/contraction deformation
of, e.g., each of the bearings (61, 62, 63, 64), a clearance (gap)
in the sliding section cannot be maintained at a desired length.
Consequently, there is a possibility to cause an increase in
sliding resistance and a reduction in rigidity of the sliding
section. However, the aniline point of the refrigerant oil is set
within the predetermined value range, thereby reducing the
expansion/contraction deformation of the bearings (61, 62, 63, 64).
Thus, the above-described disadvantages can be avoided.
[0102] An acid trapping agent, an extreme pressure additive, an
antioxidizing agent, an antifoam agent, an oiliness agent, and a
copper deactivator are added to the refrigerant oil of the present
embodiment as additives. All of the six additives are used in the
present embodiment. However, each of the additives may be added as
necessary, and only a single type of additive may be added. A
compounding amount of each additive is set so that the proportion
contained in the refrigerant oil is equal to or greater than 0.01%
by mass and equal to or less than 5% by mass. Compounding amounts
of the acid trapping agent and of the antioxidizing agent
preferably fall within a range of equal to or greater than 0.05% by
mass and equal to or less than 3% by mass.
[0103] For the acid trapping agent, the following can be used:
epoxy compounds such as phenyl glycidyl ether, alkyl glycidyl
ether, alkylene glycol glycidyl ether, cyclohexene oxide,
.alpha.-olefin oxide, and epoxidized soybean oil. Among these
agents, the acid trapping agents preferable in terms of the
compatibility are phenyl glycidyl ether, alkyl glycidyl ether,
alkylene glycol glycidyl ether, cyclohexene oxide, and
.alpha.-olefin oxide. An alkyl group of alkyl glycidyl ether and an
alkylene group of alkylene glycol glycidyl ether may have branches.
The carbon number of such groups may be equal to or greater than 3
and equal to or less than 30; preferably equal to or greater than 4
and equal to or less than 24; and more preferably equal to or
greater than 6 and equal to or less than 16. In addition, for
.alpha.-olefin oxide, the total carbon number may be equal to or
greater than 4 and equal to or less than 50; preferably equal to or
greater than 4 and equal to or less than 24; and more preferably
equal to or greater than 6 and equal to or less than 16. A single
type of acid trapping agent may be used, or multiple types of acid
trapping agents may be combined.
[0104] An extreme pressure additive containing phosphoric esters
may be used. As phosphoric esters, the following may be used:
phosphoric ester; phosphite ester; acidic phosphoric ester; acidic
phosphite ester; etc. In addition, an extreme pressure additive may
be used, which contains phosphoric esters such as phosphoric ester,
phosphite ester, acidic phosphoric ester, and acidic phosphite
ester which contain amine salt.
[0105] Phosphoric ester includes, e.g., triaryl phosphate; trialkyl
phosphate; trialkyl aryl phosphate; triaryl alkyl phosphate; and
trialkenyl phosphate. Further, phosphoric ester specifically
includes, e.g., triphenyl phosphate; tricresyl phosphate; benzyl
diphenyl phosphate; ethyl diphenyl phosphate; tributyl phosphate;
ethyl dibutyl phosphate; cresyl diphenyl phosphate; dicresyl phenyl
phosphate; ethyl phenyl diphenyl phosphate; diethyl phenyl phenyl
phosphate; propyl phenyl diphenyl phosphate; dipropyl phenyl phenyl
phosphate; triethyl phenyl phosphate; tripropyl phenyl phosphate;
butyl phenyl diphenyl phosphate; dibutyl phenyl phenyl phosphate;
tributyl phenyl phosphate; trihexyl phosphate; tri(2-ethylhexyl)
phosphate; tridecyl phosphate; trilauryl phosphate; trimyristyl
phosphate; tripalmityl phosphate; tristearyl phosphate; and
trioleyl phosphate.
[0106] Phosphite ester specifically includes, e.g., triethyl
phosphite; tributyl phosphite; triphenyl phosphite; tricresyl
phosphite; tri(nonylphenyl) phosphite; tri(2-ethylhexyl) phosphite;
tridecyl phosphite; trilauryl phosphite; triisooctyl phosphite;
diphenyl isodecyl phosphite; tristearyl phosphite; and trioleyl
phosphite.
[0107] Acidic phosphoric ester specifically includes, e.g.,
2-ethylhexyl acid phosphate; ethyl acid phosphate; butyl acid
phosphate; oleyl acid phosphate; tetracosyl acid phosphate;
isodecyl acid phosphate; lauryl acid phosphate; tridecyl acid
phosphate; stearyl acid phosphate; and isostearyl acid
phosphate.
[0108] Acidic phosphite ester specifically includes, e.g., dibutyl
hydrogen phosphite; dilauryl hydrogen phosphite; dioleyl hydrogen
phosphite; distearyl hydrogen phosphite; and diphenyl hydrogen
phosphite. Among the above-described phosphoric esters, oleyl acid
phosphate or stearyl acid phosphate is preferable.
[0109] Mono-substituted amine of amine used for amine salt of
phosphoric ester, phosphite ester, acidic phosphoric ester, or
acidic phosphite ester specifically includes, e.g., butylamine;
pentylamine; hexylamine; cyclohexylamine; octylamine; laurylamine;
stearylamine; oleylamine; and benzylamine. Di-substituted amine
specifically includes, e.g., dibutylamine; dipentylamine;
dihexylamine; dicyclohexylamine; dioctylamine; dilaurylamine;
distearylamine; dioleylamine; dibenzylamine; stearyl
monoethanolamine; decyl monoethanolamine; hexyl monopropanolamine;
benzyl monoethanolamine; phenyl monoethanolamine; and tolyl
monopropanolamine. Tri-substituted amine specifically includes,
e.g., tributylamine; tripentylamine; trihexylamine;
tricyclohexylamine; trioctylamine; trilaurylamine; tristearylamine;
trioleylamine; tribenzylamine; dioleyl monoethanolamine; dilauryl
monopropanolamine; dioctyl monoethanolamine; dihexyl
monopropanolamine; dibutyl monopropanolamine; oleyl diethanolamine;
stearyl dipropanolamine; lauryl diethanolamine; octyl
dipropanolamine; butyl diethanolamine; benzyl diethanolamine;
phenyl diethanolamine; tolyl dipropanolamine; xylyl diethanolamine;
triethanolamine; and tripropanolamine.
[0110] In addition, extreme pressure additives other than the above
may be added. For example, the following may be used: an organic
sulfur compound extreme pressure additive such as monosulfides,
polysulfides, sulfoxides, sulfones, thiosulfinates, oil sulfides,
thiocarbonates, thiophenes, thiazoles, and methanesulfonate esters;
a thiophosphate extreme pressure additive such as thiophosphate
triesters; an ester extreme pressure additive such as higher fatty
acids, hydroxyaryl fatty acids, polyhydric alcohol esters, and
acrylic acid esters; an organic chloride extreme pressure additive
such as chlorinated hydrocarbons and chlorinated carboxylic acid
derivatives; an organic fluorine extreme pressure additive such as
fluorinated aliphatic carboxylic acids, fluorinated ethylene resin,
fluorinated alkyl polysiloxanes, and fluorinated graphites; an
alcohol extreme pressure additive such as higher alcohol; and a
metal compound extreme pressure additive such as naphthenates (lead
naphthenate etc.), fatty acid salts (lead fatty acid etc.),
thiophosphates (zinc dialkyl phosphorodithioate etc.), thiocarbamic
acid salts, an organic molybdenum compound, an organotin compound,
an organogermanium compound, and borate esters.
[0111] For the antioxidizing agent, a phenol antioxidizing agent or
an amine antioxidizing agent may be used. The phenol antioxidizing
agent includes, e.g., 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; and 2, 6-di-tert-butylphenol. In
addition, the amine antioxidizing agent includes, e.g., N,
N'-diisopropyl-p-phenylenediamine; N,
N'-di-sec-butyl-p-phenylenediamine; phenyl-.alpha.-naphthylamine;
and N, N' -di-phenyl-p-phenylenediamine. For the antioxidizing
agent, an oxygen trapping agent for trapping oxygen may be
used.
[0112] For the copper deactivator, benzotriazole, a derivative
thereof, etc. may be used. For the antifoam agent, a silicon
compound may be used. For the oiliness agent, higher alcohols may
be used.
[0113] As necessary, a load withstanding additive, a chlorine
trapping agent, a detergent dispersant, a viscosity index improver,
an antirust agent, a stabilizer, a corrosion inhibitor, a
fluid-point lowering agent, etc. may be added to the refrigerant
oil of the present embodiment. A compounding amount of each
additive may be set so that the proportion contained in the
refrigerant oil is equal to or greater than 0.01% by mass and equal
to or less than 5% by mass, preferably equal to or greater than
0.05% by mass and equal to or less than 3% by mass. The refrigerant
oil of the present embodiment has a chlorine concentration of equal
to or less than 50 ppm, and a sulfur concentration of equal to or
less than 50 ppm.
[0114] Operation
[0115] An operation of the air conditioning system (20) will be
described. The air conditioning system (20) can perform a cooling
operation and a heating operation, and switches between the cooling
operation and the heating operation by the four-way switching valve
(13).
[0116] <<Cooling Operation>>
[0117] In the cooling operation, the four-way switching valve (13)
is set to the first state. In such a state, when operating the
compressor (30), high-pressure refrigerant discharged from the
compressor (30) is condensed by releasing heat to outdoor air in
the outdoor heat exchanger (11). The refrigerant condensed in the
outdoor heat exchanger (11) is distributed to each of the indoor
circuits (17). The pressure of the refrigerant flowing into the
indoor circuit (17) is reduced by the indoor expansion valve (16),
and then such refrigerant is evaporated by absorbing heat from room
air in the indoor heat exchanger (15). Meanwhile, room air is
cooled and supplied to a room.
[0118] The refrigerant evaporated in the indoor circuit (17) joins
the refrigerant evaporated in the other indoor circuits (17), and
then is returned to the outdoor circuit (9). In the outdoor circuit
(9), the refrigerant returned from the indoor circuits (17) is
recompressed in the compressor (30), and then such refrigerant is
discharged. During the cooling operation, a superheat degree
control is performed, in which the opening of the indoor expansion
valve (16) is controlled so that the degree of superheat of
refrigerant at an outlet port of the indoor heat exchanger (15) is
a constant value (e.g., 5.degree. C.).
[0119] <<Heating Operation>>
[0120] In the heating operation, the four-way switching valve (13)
is set to the second state. In such a state, when operating the
compressor (30), high-pressure refrigerant discharged from the
compressor (30) is distributed to each of the indoor circuits (17).
The refrigerant flowing into the indoor circuit (17) is condensed
by releasing heat to room air in the indoor heat exchanger (15).
Meanwhile, room air is heated and supplied to a room. The
refrigerant condensed in the indoor heat exchanger (15) joins the
refrigerant condensed in the other indoor heat exchangers (15) in
the outdoor circuit (9).
[0121] The pressure of the refrigerant joined each other in the
outdoor circuit (9) is reduced by the outdoor expansion valve (12),
and then such refrigerant is evaporated by absorbing heat from
outdoor air in the outdoor heat exchanger (11). The refrigerant
evaporated in the outdoor heat exchanger (11) is recompressed in
the compressor (30), and then such refrigerant is discharged.
During the heating operation, a subcooling control is performed, in
which the opening of the indoor expansion valve (16) is controlled
so that the degree of supercool of refrigerant at the outlet port
of the indoor heat exchanger (15) is a constant value (e.g.,
5.degree. C.).
Advantages of Embodiment
[0122] In the present embodiment, as the refrigerant of the
refrigerant circuit (10), the refrigerant represented by Molecular
Formula 1: C.sub.3H.sub.mF.sub.n (note that "m" and "n" are the
integers equal to or greater than 1 and equal to or less than 5,
and the relationship represented by the expression m+n=6 is
satisfied) and having the single double bond in the molecular
structure is used. This provides the air conditioning system (20)
with a higher theoretical coefficient of performance (COP) of the
refrigeration cycle.
[0123] On the other hand, the HFO-1234yf has a relatively-unstable
molecular structure due to, e.g., the structure having the double
bond, and refrigerant is likely to be deteriorated to generate
impurities etc. Thus, there is a possibility that such impurities
chemically/physically denature and deteriorate the functional resin
components (i.e., bearings (61, 62, 63, 64)) of the air
conditioning system (20). However, in the present invention, each
of the bearings (61, 62, 63, 64) is made of any of
polytetrafluoroethylene, polyphenylene sulfide, and polyimide
resin, and such resin materials have relatively-high stability to
the impurities generated from refrigerant. Thus, the deterioration
of the bearings (61, 62, 63, 64) due to the influence of the
impurities can be avoided, thereby obtaining a desired sliding
capability in the bearings (61, 62, 63, 64).
[0124] In the present embodiment, the refrigerant oil having the
saturated water amount of equal to or greater than 2000 ppm at the
temperature of 30.degree. C. and the relative humidity of 90% is
used, thereby trapping moisture in refrigerant by the refrigerant
oil. This reduces or prevents deterioration of the HFO-1234yf due
to an influence of moisture. In addition, the refrigerant oil has
the chlorine concentration of equal to or less than 50 ppm, thereby
reducing or preventing acceleration of the deterioration of
refrigerant due to an influence of chloride components. Further,
the refrigerant oil has the sulfur concentration of equal to or
less than 50 ppm, thereby reducing or preventing the acceleration
of the deterioration of refrigerant due to an influence of sulfur
components. As described above, in the present embodiment, the
refrigerant oil is selected so that the deterioration of
refrigerant is reduced or prevented as much as possible, thereby
reducing the generation of impurities due to the deterioration of
refrigerant. Consequently, the denaturalization/deterioration of
the bearings (61, 62, 63, 64) can be effectively reduced or
prevented.
[0125] The refrigerant oil contains at least one of polyalkylene
glycol, polyol ester, and polyvinyl ether as the main component.
This allows refrigerant and the refrigerant oil to easily dissolve
each other. Thus, even if the refrigerant oil flows into the
refrigerant circuit (10), such refrigerant oil is dissolved with
refrigerant, and is easily sent back to the compressor (30). As a
result, excessive oil discharge from the compressor (30) can be
reduced, thereby avoiding a shortage of the refrigerant oil and
inadequate lubrication in the compressor (30). Consequently,
reliability of the compressor (30) can be improved.
[0126] The refrigerant oil may be deteriorated due to a long-term
refrigeration cycle, resulting in generation of impurities.
However, the bearings (61, 62, 63, 64) of the present embodiment
are made of polytetrafluoroethylene or polyamide resin, thereby
avoiding the chemical/physical denaturalization of the bearings
(61, 62, 63, 64) due to the influence of the impurities caused due
to the deterioration of the refrigerant oil.
[0127] Difluoromethane which is so-called "high-pressure
refrigerant" is added to the refrigerant represented by Molecular
Formula 1 and having the single double bond in the molecular
structure. This reduces an influence of a pressure loss of
refrigerant on an operational efficiency of the air conditioning
system (20), thereby improving an actual operational efficiency of
the air conditioning system (20).
First Variation of Embodiment
[0128] In a first variation of the present embodiment, refrigerant
oil mainly containing only polyol ester of three base oils which
are polyalkylene glycol, polyol ester, and polyvinyl ether is used
for the compressor (30). Any of the following is used for polyol
ester: "ester of aliphatic polyhydric alcohol and linear or
branched fatty acid," "partial ester of aliphatic polyhydric
alcohol and linear or branched fatty acid," and "complex ester of
partial ester of aliphatic polyhydric alcohol and linear or
branched fatty acid having the carbon number of equal to or greater
than 3 and equal to or less than 9, and aliphatic or aromatic
dibasic acid." Among polyol esters, such polyol esters have
excellent compatibility with refrigerant represented by Molecular
Formula 1 and having the single double bond in the molecular
structure.
[0129] Aliphatic polyhydric alcohol contained in the "ester of" or
"partial ester of aliphatic polyhydric alcohol and linear or
branched fatty acid" includes, e.g., ethylene glycol; propylene
glycol; butylene glycol; neopentyl glycol; trimethylolethane;
ditrimethylolethane; trimethylolpropane; ditrimethylolpropane;
glycerin; pentaerythritol; dipentaerythritol; tripentaerythritol;
and sorbitol. As aliphatic polyhydric alcohol, pentaerythritol,
dipentaerythritol, and tripentaerythritol are preferable.
[0130] Fatty acid having the carbon number of equal to or greater
than 3 and equal to or less than 12 may be used. For fatty acid,
the following may be used: propionic acid; butyric acid; pivalic
acid; valeric acid; caproic acid; heptanoic acid; octanoic acid;
nonanoic acid; decanoic acid; dodecanoic acid; isovaleric acid;
neopentanoic acid; 2-methyl-butyric acid; 2-ethyl-butyric acid;
2-methyl-hexanoic acid; 2-ethyl-hexanoic acid; iso-octanoic acid;
iso-nonanoic acid; iso-decanoic acid; 2, 2-dimethyl-octanoic acid;
2-butyloctanoic acid; and 3, 5, 5-trimethylhexane acid. As fatty
acid, the carbon number is preferably equal to or greater than 5
and equal to or less than 12, and more preferably equal to or
greater than 5 and equal to or less than 9. Specifically, valeric
acid, hexanoic acid, heptanoic acid, 2-methyl-hexanoic acid,
2-ethyl-hexanoic acid, iso-octanoic acid, iso-nonanoic acid,
iso-decanoic acid, 2, 2-dimethyl-octanoic acid, 2-butyloctanoic
acid, 3, 5, 5-trimethylhexane acid, etc. are preferable.
[0131] In the "complex ester of partial ester of aliphatic
polyhydric alcohol and linear or branched fatty acid having the
carbon number of equal to or greater than 3 and equal to or less
than 9, and aliphatic or aromatic dibasic acid," fatty acid having
the carbon number of equal to or greater than 5 and equal to or
less than 7 is preferable, and fatty acid having the carbon number
of 5 or 6 is more preferable. Specifically, valeric acid, hexanoic
acid, isovaleric acid, 2-methyl-butyric acid, 2-ethyl-butyric acid,
or mixture thereof is preferable. Fatty acid may be used, in which
fatty acid having the carbon number of 5 is mixed with fatty acid
having the carbon number of 6 at a weight ratio equal to or greater
than 10:90 and equal to or less than 90:10.
[0132] Aliphatic dibasic acid includes succinic acid, adipic acid,
pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanoic
diacid, dodecanoic diacid, tridecanoic diacid, and docosanoic
diacid. Aromatic dibasic acid includes phthalic acid and
isophthalic acid. In an esterification reaction for preparing
complex ester, polyhydric alcohol reacts with dibasic acid at a
predetermined rate for partial esterification, and then such
partial ester reacts with fatty acid. A reaction sequence of
dibasic acid and fatty acid may be reversed, and dibasic acid may
be mixed with fatty acid for esterification.
Second Variation of Embodiment
[0133] In a second variation of the present embodiment, refrigerant
oil mainly containing only polyalkylene glycol of three base oils
which are polyalkylene glycol, polyol ester, and polyvinyl ether is
used for the compressor (30).
[0134] In the second variation, polyalkylene glycol is used, which
has a molecular structure represented by Molecular Formula 2:
R1(R2).sub.m(R30).sub.nR4 (note that "m" and "n" are integers,
symbols "R1" and "R4" represent an alkyl or aryl group having the
hydrogen or carbon number of equal to or greater than 1 and equal
to or less than 6, and symbols "R2" and "R3" represent an alkyl
group having the carbon number of equal to or greater than 1 and
equal to or less than 4). Among polyalkylene glycols, polyalkylene
glycol having such a molecular structure has excellent
compatibility with the refrigerant represented by Molecular Formula
1 and having the single double bond in the molecular structure.
Third Variation of Embodiment
[0135] As long as the functional resin components are arranged so
as to contact refrigerant, the resin material of the present
invention may be applicable to an inside and an outside (functional
components to be connected to the refrigerant circuit (10)) of the
compressor (30). In such a case, the functional resin components
are preferably made of any of polytetrafluoroethylene,
polyphenylene sulfide, phenolic resin, polyamide resin, chloroprene
rubber, silicone rubber, hydrogenated nitrile rubber,
fluorine-containing rubber, and hydrin rubber. This will be
described in detail below.
[0136] <Sliding Member>
[0137] Sliding members made of fluorine resin, e.g., any of
polytetrafluoroethylene, polyphenylene sulfide, and polyamide
resin, may be formed on surfaces of the sliding sections of, e.g.,
the movable scroll (76), the fixed scroll (75), and the Oldham's
ring (79).
[0138] The resin material of the present invention may be
applicable to the sliding members applied to the functional
components of the refrigerant circuit (10) outside the compressor
(30). Specifically, the sliding member made of fluorine resin,
e.g., any of polytetrafluoroethylene, polyphenylene sulfide, and
polyamide resin, may be applicable to, e.g., a sliding section of a
valving element of the four-way switching valve (13). In
particular, in the sliding section of the valving element, 66 nylon
is preferably used as the above-described polyamide resin.
[0139] <Sealing Member>
[0140] The resin material of the present invention may be
applicable to a sealing member for reducing or preventing a leakage
of refrigerant. In, e.g., FIG. 4, a seal ring (65) is inserted
between the movable-side end plate (76b) of the movable scroll (76)
and an upper surface of the housing (77) as a sealing member. The
seal ring (65) divides a space above the housing (77) into inner
and outer sections. That is, the seal ring (65) reduces or prevents
a leakage of high-pressure refrigerant on an inner circumferential
side thereof to an outer circumferential side, i.e., the suction
side of the compressor (30). The seal ring (65) is preferably made
of any of polytetrafluoroethylene, polyphenylene sulfide,
chloroprene rubber, silicone rubber, hydrogenated nitrile rubber,
fluorine-containing rubber, and hydrin rubber. Such resin materials
has relatively-high stability to impurities generated due to
deterioration of refrigerant. Consequently, deterioration of the
seal ring (65) due to the generation of the impurities is
reduced.
[0141] Sealing members to which the present invention is applied
includes, e.g., an O-ring inserted between an inner circumferential
surface of the casing (70) and an outer circumferential surface of
the housing (77); and a packing inserted in a pipe joint section of
the discharge pipe (56) or the suction pipe (57).
[0142] The resin material of the present invention may be
applicable to the sealing members applied to the functional
components of the refrigerant circuit (10) outside the compressor
(30). Specifically, in, e.g., the four-way switching valve (13),
the expansion valves (12, 16a, 16b, 16c), and other solenoid
valves, the sealing member for reducing or preventing an outflow of
refrigerant to outside may be made of any of
polytetrafluoroethylene, polyphenylene sulfide, chloroprene rubber,
silicone rubber, hydrogenated nitrile rubber, fluorine-containing
rubber, and hydrin rubber.
[0143] If the resin material of the present invention is applied to
the seal ring (65), the aniline point of the refrigerant oil is
preferably set within the predetermined value range. This reduces
the expansion or contraction of the seal ring (65). Consequently,
reduction in or degradation of sealing capability of the seal ring
(65) can be reduced or prevented, thereby ensuring the sealing
capability of the seal ring (65) over a long period of time.
[0144] <Other Structural Components>
[0145] Further, the resin material of the present invention may be
applicable to other components (structural components) other than
the above. Specifically, e.g., pipes for guiding the refrigerant
oil to a predetermined section, and valving elements themselves of
the four-way switching valve (13), the expansion valves (12, 16a,
16b, 16c), the other solenoid valves, etc. may be made of any of
fluorine resin, phenolic resin, and polyamide resin (preferably
nylon 66).
[0146] <<Other Embodiments>>
[0147] The foregoing embodiments may have the following
configurations.
[0148] In the foregoing embodiments, refrigerant oil may be used,
which mainly contains two or more of polyalkylene glycol, polyol
ester, and polyvinyl ether.
[0149] In the foregoing embodiments, as the refrigerant of the
refrigerant circuit (10), single component refrigerant of
refrigerant represented by Molecular Formula 1 and having the
single double bond in the molecular structure, other than the
HFO-1234yf may be used. Specifically, the following may be used: 1,
2, 3, 3, 3-pentafluoro-1-propene (referred to as "HFO-1225ye," and
a chemical formula thereof is represented by an expression
CF.sub.3-CF=CHF); 1, 3, 3, 3-tetrafluoro-1-propene (referred to as
"HFO-1234ze," and a chemical formula thereof is represented by an
expression CF.sub.3-CH=CHF); 1, 2, 3, 3-tetrafluoro-1-propene
(referred to as "HFO-1234ye," and a chemical formula thereof is
represented by an expression CHF.sub.2-CF=CHF); 3, 3,
3-trifluoro-1-propene (referred to as "HFO-1243zf," and a chemical
formula thereof is represented by an expression
CF.sub.3-CH=CH.sub.2); 1, 2, 2-trifluoro-1-propene (a chemical
formula thereof is represented by an expression
CH.sub.3-CF=CF.sub.2); and 2-fluoro-1-propene (a chemical formula
thereof is represented by an expression CH.sub.3-CF=CH.sub.2).
[0150] In the foregoing embodiments, refrigerant mixture may be
used, which is made by adding at least one of HFC-32
(difluoromethane), HFC-125 (pentafluoroethane), HFC-134 (1, 1, 2,
2-tetrafluoroethane), HFC-134a (1, 1, 1, 2-tetrafluoroethane),
HFC-143a (1, 1, 1-trifluoroethane), HFC-152a (1, 1-difluoroethane),
HFC-161, HFC-227ea, HFC-236ea, HFC-236fa, HFC-365mfc, methane,
ethane, propane, propene, butane, isobutene, pentane,
2-methylbutane, cyclopentane, dimethyl ether,
bis-trifluoromethyl-sulfide, carbon dioxide, and helium; to the
refrigerant represented by Molecular Formula 1 and having the
single double bond in the molecular structure (2, 3, 3,
3-tetrafluoro-1 -propene; 1, 3, 3, 3-tetrafluoro-1-propene; 1, 2,
3, 3-tetrafluoro-1-propene; 3, 3, 3-trifluoro-1-propene; 1, 2,
2-trifluoro-1-propene; and 2-fluoro-1-propene).
[0151] Refrigerant mixture of, e.g., the HFO-1234yf and the HFC-32
may be used. In such a case, the refrigerant mixture may be used,
which contains the HFO-1234yf of 78.2% by mass and the HFC-32 of
21.8% by mass. In the refrigerant mixture of the HFO-1234yf and the
HFC-32, the proportion of the HFO-1234yf may be equal to or greater
than 70% by mass and equal to or less than 94% by mass, and the
proportion of the HFC-32 may be equal to or greater than 6% by mass
and equal to or less than 30% by mass. The proportion of the
HFO-1234yf is preferably equal to or greater than 77% by mass and
equal to or less than 87% by mass, and the proportion of the HFC-32
may be equal to or greater than 13% by mass and equal to or less
than 23% by mass. More preferably, the proportion of the HFO-1234yf
is equal to or greater than 77% by mass and equal to or less than
79% by mass, and the proportion of the HFC-32 is equal to or
greater than 21% by mass and equal to or less than 23% by mass.
[0152] Refrigerant mixture of the HFO-1234yf and the HFC-125 may be
used. In such a case, the proportion of the HFC-125 is preferably
equal to or greater than 10% by mass, and more preferably equal to
or greater than 10% by mass and equal to or less than 20% by
mass.
[0153] Refrigerant mixture of the HFO-1234yf, the HFC-32, and the
HFC-125 may be used. In such a case, refrigerant mixture may be
used, which contains the HFO-1234yf of 52% by mass, the HFC-32 of
23% by mass, and the HFC-125 of 25% by mass.
[0154] In the foregoing embodiments, a dryer filled with silicic
acid or synthetic zeolite as desiccant may be provided in the
refrigerant circuit (10).
[0155] In the foregoing embodiments, the compressor (30) may be a
horizontal compressor, or may be other types of compressors such as
reciprocating, rotary, and screw compressors.
[0156] In the foregoing embodiments, the refrigeration apparatus
(20) may be an air conditioning system only for heating; a
refrigerator or a freezer for cooling food; a refrigeration system
in which an air conditioner is combined with a refrigerator or a
freezer; or a hot-water supply system in which water is heated in a
radiator of a refrigerant circuit (10).
[0157] The foregoing embodiments have been set forth merely for
purposes of preferred examples in nature, and are not intended to
limit the scope, applications, and use of the invention.
INDUSTRIAL APPLICABILITY
[0158] As described above, the present invention is useful for the
refrigeration apparatus in which the refrigeration cycle is
performed.
* * * * *