U.S. patent application number 13/388192 was filed with the patent office on 2012-05-31 for refrigeration cycle apparatus.
This patent application is currently assigned to PANASONIC CORPORATION. Invention is credited to Daisuke Funakoshi, Noboru Iida, Tsuyoshi Karino, Masao Nakano.
Application Number | 20120131947 13/388192 |
Document ID | / |
Family ID | 43096325 |
Filed Date | 2012-05-31 |
United States Patent
Application |
20120131947 |
Kind Code |
A1 |
Nakano; Masao ; et
al. |
May 31, 2012 |
REFRIGERATION CYCLE APPARATUS
Abstract
An object of the present invention is to provide a refrigeration
cycle apparatus having a compressor that is not easily heated to
high temperature by sliding heat and thus higher in reliability.
Provided is a refrigeration cycle apparatus having a cost-effective
compressor in the configuration in which a piston 9 eccentrically
revolving, as driven by a shaft 4, is placed in a cylinder 6 and
the circular terminal region 10a of a vane 10 partitioning the
cylinder 6 into a suction chamber 12 and a compression chamber 13
is connected slidably to the external surface of the piston 9 in
surface contact, which can reduce the sliding heat and is thus
resistant to deterioration in reliability by reaction of the
operating refrigerant.
Inventors: |
Nakano; Masao; (Shiga,
JP) ; Iida; Noboru; (Shiga, JP) ; Funakoshi;
Daisuke; (Shiga, JP) ; Karino; Tsuyoshi;
(Shiga, JP) |
Assignee: |
PANASONIC CORPORATION
Osaka
JP
|
Family ID: |
43096325 |
Appl. No.: |
13/388192 |
Filed: |
September 16, 2010 |
PCT Filed: |
September 16, 2010 |
PCT NO: |
PCT/JP2010/066618 |
371 Date: |
January 31, 2012 |
Current U.S.
Class: |
62/468 ;
62/498 |
Current CPC
Class: |
C10N 2020/101 20200501;
C10M 2209/1023 20130101; F25B 1/04 20130101; C09K 2205/22 20130101;
C10M 2205/223 20130101; C10N 2040/30 20130101; C09K 5/045 20130101;
C10M 2205/0285 20130101; C09K 2205/24 20130101; C10M 2209/043
20130101; F25B 2400/121 20130101; C10M 2207/2835 20130101; C10M
2209/1033 20130101; C10M 171/008 20130101; C09K 2205/126 20130101;
C10M 2209/043 20130101; C10M 2209/1033 20130101 |
Class at
Publication: |
62/468 ;
62/498 |
International
Class: |
F25B 1/00 20060101
F25B001/00; F25B 41/00 20060101 F25B041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 17, 2010 |
JP |
2010-060626 |
Claims
1. A refrigeration cycle apparatus, comprising: a rotary
compressor, using a single refrigerant of a hydrofluoroolefin
having a carbon-carbon double bond or a mixed refrigerant at least
containing the hydrofluoroolefin and additionally hydrofluorocarbon
having no double bond as an operating refrigerant and having a
motor and a compression mechanism unit driven by a rotor of the
motor in a tightly sealed container, the compression mechanism unit
having a piston eccentrically revolving, as driven by a shaft, in a
cylinder, the terminal region of a vane, which partitions the
cylinder into a suction chamber and a compression chamber, being
slidably connected to the external surface of the piston; a
condenser cooling the refrigerant gas pressurized, as compressed by
the compressor; a throttling mechanism depressurizing the
high-pressure refrigerant liquefied by the condenser; and a
vaporizer gasifying the depressurized liquid refrigerant, wherein
the rotary compressor, the condenser, the throttling mechanism and
the vaporizer are connected to each other with piping.
2. The refrigeration cycle apparatus according to claim 1, wherein
the terminal region of the rotary compressor vane and the external
surface of the piston are slidably connected to each other, by the
circular terminal region of the vane and an arc-shaped slot on the
external surface of the piston.
3. The refrigeration cycle apparatus according to claim 2, wherein
the angle of connection of the arc-shaped slot is 180.degree. or
more.
4. The refrigeration cycle apparatus according to claim 1, wherein
the operating refrigerant is a two- or three-component mixed
refrigerant containing a hydrofluoroolefin tetrafluoropropene
(HFO1234yf) as primary component, and one or more hydrofluorocarbon
having no double bond and selected from the group consisting of
difluoromethane, pentafluoroethane and tetrafluoroethane, the
hydrofluorocarbon being added at a rate to give a global warming
potential of 5 or more and 750 or less.
5. The refrigeration cycle apparatus according to claim 1, wherein
the refrigeration oil is a synthetic oil containing an
oxygen-containing compound selected from the group consisting of
polyoxyalkylene glycols, polyvinylethers, copolymers of
poly(oxy)alkylene glycols or the monoethers thereof and
polyvinylether, polyol esters and polycarbonates as a principal
component or a synthetic oil containing an alkyl benzene or an
.alpha.-olefin as a principal component.
Description
TECHNICAL FIELD
[0001] The present invention relates to a high-reliability
refrigeration cycle apparatus, such as room air conditioner,
refrigerator or air conditioning apparatus, using a refrigerant
mainly containing a chlorine atom-free low-global warming potential
hydrofluoroolefin having a carbon-carbon double bond as its
operating refrigerant and employing a rotary compressor as its
compressor.
BACKGROUND ART
[0002] The operating refrigerants used in conventional
refrigeration cycle apparatuses are shifting to HFC
(hydrofluorocarbon) compounds having zero ozone depletion
potential, but these HFC-based refrigerants are also causing a
problem recently, because they have very high global warming
potential. Thus, refrigeration cycle apparatuses using a
refrigerant mainly containing chlorine atom-free low-global warming
potential hydrofluoroolefin having a carbon-carbon double bond have
been studied. Lubricant materials for this kind of rotary
compressors used with conventional HFC-based refrigerants have been
modified in various ways to assure reliability (see, for example,
Patent Document 1).
[0003] FIG. 5 is a crosssectional view of a rotary compressor used
with the conventional HFC (hydrofluorocarbon)-based refrigerant
described in Patent Document 1. In the configuration, a piston 43
is inserted along the internal surface of a cylinder 41 and
revolves with revolution of a shaft 42, and a refrigerant gas is
suctioned and compressed respectively in a suction chamber 45 and a
compression chamber 46 partitioned by a vane 44. Obviously from its
mechanical configuration, the areas of the rotary compressor
abraded most intensively are where the terminal region of the vane
44 and the external surface of the piston 43 are in contact with
each other, and high discharge pressure is applied to a rear face
of the vane 44, the end of the vane 44 is pressed onto the external
surface of the piston 43 by line contact, intensively by the
pressure difference between the discharge pressure and the pressure
in the cylinder, leading to increase in surface pressure and
boundary lubrication. In addition, the vane was subjected to
nitridation treatment or CrN or TiN ion plating on the surface, for
improvement of its abrasion resistance and assurance of
reliability.
[0004] FIG. 6 is a crosssectional view illustrating a swing rotary
compressor used with the conventional HFC (hydrofluorocarbon)-based
refrigerant described in Patent Document 2. It is a swing rotary
compressor having a piston 53 consisting of a roller 53a and a vane
54 formed as integrated with the roller 53a. In the configuration,
the vane 54 is held slidably between two semi-cylindrical sliding
parts 57 in a cylindrical hole unit 51a formed outside the internal
surface of a cylinder 51; the piston 53 is inserted into the
cylinder 51 from the internal surface for movement thereof by
revolution of a shaft 52, and the refrigerant gas is suctioned and
compressed respectively in a suction chamber 55 and a compression
chamber 56 partitioned by the vane 54.
[0005] Because the roller 53a and the vane 54 are formed as an
integrated structure in the swing rotary compressor, differently
from the rotary compressor described in Patent Document 1, the vane
terminal region and the piston external surface are not in contact
with each other, and the semi-cylindrical sliding parts and the
cylindrical hole unit 51a formed in the cylinder 51 are in surface
contact with each other, and thus, the sliding state is
relaxed.
CITATION LIST
[0006] Patent Document 1: JP-A 11-236890 [0007] Patent Document 2:
JP-A 2003-106692
SUMMARY OF INVENTION
Technical Problem
[0008] However, when a rotary compressor of refrigeration apparatus
using a refrigerant mainly containing a chlorine atom-free
low-global warming potential hydrofluoroolefin having a
carbon-carbon double bond is considered, there was a problem, under
severe environment at high temperature because of the sliding heat
caused by boundary lubrication, particularly because the surface
pressure is raised, as the vane terminal region and the piston
external surface are pressed in line contact, that hydrogen
fluoride is generated in reaction with the refrigerant and thus,
abrasion of the vane terminal region and the piston external
surface is accelerated and the refrigeration oil is decomposed,
leading to decrease in reliability. When the configuration of swing
compressor is employed, the contact changes from line contact to
surface contact, leading to relaxation of sliding, but, because the
piston has an integrated structure of roller and vane, it was very
expensive to produce it at high accuracy. Because two sliding parts
demanding severe processing accuracy are needed additionally, the
increase in the number of parts also led to increase in production
cost.
[0009] An object of the present invention, which was made to solve
the problems of traditional technology, is to provide a
cost-effective compressor that is resistant to decomposition of its
refrigerant, as the sliding heat is reduced by alteration of the
contact between the vane terminal region and the piston external
surface from line contact to surface contact, and thus, assures
reliability of the compressor and yet retains the configuration of
conventional rotary compressors as much as possible.
Solution to Problem
[0010] The refrigeration cycle apparatus according to the present
invention, which achieved the object above, has therein a rotary
compressor using a single refrigerant of a hydrofluoroolefin having
a carbon-carbon double bond or a mixed refrigerant containing the
hydrofluoroorefin as the primary component and hydrofluorocarbons
having no double bond as the operating refrigerant and having a
piston eccentrically revolving, as driven by a shaft, in a
cylinder, the terminal region of a vane, which partitions the
cylinder into a suction chamber and a compression chamber, being
slidably connected to the external surface of the piston.
[0011] It is possible in this way to reduce generation of hydrogen
fluoride that occurs when the refrigerant reacts with water and
oxygen, because, in the rotary compressor, the vane terminal region
is slidably connected to the piston external surface, leading to
change from severe boundary lubrication state of line contact to
surface contact lubrication state and the sliding parts are not
heated significantly.
[0012] Because, in the rotary compressor, the vane terminal region
is slidably connected to the piston external surface, leading to
change from severe boundary lubrication state of line contact to
surface contact lubrication state and the sliding parts are not
heated significantly, it is possible in the refrigeration cycle
apparatus according to the present invention to reduce generation
of hydrogen fluoride that occurs when the refrigerant reacts with
water and oxygen and to provide a high-reliability refrigeration
cycle apparatus by using a refrigerant mainly containing a chlorine
atom-free low-global warming potential hydrofluoroolefin having a
carbon-carbon double bond.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1 is a chart showing the system configuration of the
refrigeration cycle apparatus in embodiment 1 of the present
invention.
[0014] FIG. 2 is a vertical crosssectional view of the rotary
compressor in embodiment 1 of the present invention.
[0015] FIG. 3 is a side crosssectional view of the compression
mechanism unit in the same rotary compressor.
[0016] FIG. 4 is a figure showing the relationship between the
global warming potential of two-component mixture refrigerants and
the blending ratio.
[0017] FIG. 5 is a side crosssectional view illustrating the
compression mechanism unit of a traditional rotary compressor.
[0018] FIG. 6 is a side crosssectional view illustrating the
compression mechanism unit of a traditional swing rotary
compressor.
DESCRIPTION OF EMBODIMENTS
[0019] The first aspect of the invention, which relates to a
refrigeration cycle apparatus, comprising a rotary compressor,
using a single refrigerant of a hydrofluoroolefin having a
carbon-carbon double bond or a mixed refrigerant containing the
hydrofluoroolefin as the primary component and hydrofluorocarbons
having no double bond as the operating refrigerant and having a
motor and a compression mechanism unit with a shaft driven by a
rotor of the motor in a tightly sealed container, the compression
mechanism unit having a piston eccentrically revolving, as driven
by a shaft, in a cylinder, the terminal region of a vane, which
partitions the cylinder into a suction chamber and a compression
chamber, being slidably connected to the external surface of the
piston, a condenser cooling the refrigerant gas pressurized, as
compressed by the compressor, a throttling mechanism depressurizing
the high-pressure refrigerant liquefied by the condenser, and a
vaporizer gasifying the depressurized liquid refrigerant, which are
connected to each other with piping. It is thus possible to reduce
heating of the sliding face and suppress generation of hydrogen
fluoride by decomposition of the refrigerant, because the contact
between the vane terminal region and the piston external surface of
the rotary compressor changes from severe line contact to slidable
connection. It is also possible to suppress abrasion of the vane
and the piston and provide a refrigeration cycle apparatus higher
in reliability by suppressing generation of hydrogen fluoride.
[0020] The second aspect of the invention, which relates to the
refrigeration cycle apparatus of the first aspect of the invention
wherein the terminal region of the rotary compressor vane and the
external surface of the piston are slidably connected to each
other, by the circular terminal region of the vane and the
arc-shaped slot on the external surface of the piston, can reduce
temperature rise by sliding, because the connecting parts are both
arc-shaped and the contact becomes surface contact.
[0021] The third aspect of the invention which relates to the
refrigeration cycle apparatus of the second aspect of the invention
wherein the angle of connection of the arc-shaped slot on the
external surface of the piston to the circular terminal region of
the vane is 180.degree. or more, can suppress separation of the
connecting parts and also can expand the contact area, thus
reducing surface pressure and temperature rise by sliding.
[0022] The fourth aspect of the invention, which relates to the
refrigeration cycle apparatus of the first to third aspects of the
invention, wherein the hydrofluoroolefin is a mixed refrigerant
containing tetrafluoropropene as the primary component and two or
three hydrofluorocarbons having no double bond, such as
difluoromethane, pentafluoroethane and tetrafluoroethane, added
thereto at a rate to give a global warming potential of 5 or more
and 750 or less, desirably 350 or less, can improve efficiency and
minimize the influence on global warming as much as possible, even
when the unrecovered refrigerant is discharged into air.
[0023] The fifth aspect of the invention, which relates to the
refrigeration cycle apparatus of the first to fourth aspects of the
invention, wherein the refrigeration oil is a synthetic oil
containing an oxygen-containing organic compound selected from the
group consisting of polyoxyalkylene glycols, polyvinylethers,
copolymers of poly(oxy)alkylene glycols or the monoether thereof
and polyvinylether, polyol esters and polycarbonates as the
principal component, or a synthetic oil containing an alkyl benzene
or an .alpha.-olefin as the principal component, can provide a
high-reliability refrigeration cycle apparatus.
[0024] Hereinafter, favorable embodiments of the present invention
will be described with reference to drawings. However, it should be
understood that the present invention is not restricted by these
embodiments.
Embodiment 1
[0025] FIG. 1 is a chart showing the system configuration of the
refrigeration cycle apparatus in the first embodiment of the
present invention.
[0026] As shown in FIG. 1, the refrigeration cycle apparatus of the
present embodiment, when explained for example as a refrigeration
cycle primary for air conditioning, mainly has a compressor 61, a
condenser 62, a throttling mechanism 63 and a vaporizer 64, and
these devices are connected to each other via a set of piping so
that the refrigerant circulates in the system.
[0027] In addition, the refrigeration cycle apparatus contains a
refrigerant mainly containing a chlorine atom-free low-global
warming potential hydrofluoroolefin having a carbon-carbon double
bond sealed therein. The refrigerant sealed in the refrigerating
apparatus is a two- or three-component mixed refrigerant containing
a hydrofluoroolefin, such as containing tetrafluoropropene
(HFO1234yf) as the primary component, and additionally one or more
hydrofluorocarbon selected from the group consisting of
difluoromethane (HFC32), pentafluoroethane (HFC125) and
tetrafluoroethane (R134a), which are added thereto at a rate to
give a global warming potential (GWP) of 4 or more and 750 or less,
desirably 4 or more and 300 or less. It may be a single refrigerant
of hydrofluoroolefin (GWP=4).
[0028] FIG. 4 is a figure showing the relationship between the
global warming potential of a two-component mixture refrigerant of
tetrafluoropropene and difluoromethane or pentafluoroethane and the
blending ratio. Specifically as shown in FIG. 4, in the case of a
two-component mixture, when tetrafluoropropene and difluoromethane
are mixed, the blending rate of difluoromethane should be 44 wt %
or less, to give a GWP of 300 or less; alternatively when
tetrafluoropropene and pentafluoroethane are mixed, the blending
rate of pentafluoroethane should be 21.3 wt % or less, to give a
GWP of 750 or less; and the blending rate of pentafluoroethane
should be 8.4 wt % or less, to give a GWP of 300 or less.
[0029] When the refrigerant is a single refrigerant of
tetrafluoropropene, it has a quite favorable GWP value of 4.
However, it has a specific volume larger and thus a refrigerating
capacity lower than those of the refrigerants mixed with
hydrofluorocarbons and, for that reason, demands a larger-scale
cooling cycle apparatus. In other words, it is possible to improve
the certain properties such as refrigerating capacity and make the
refrigerant more easily usable, compared to a single refrigerant of
hydrofluoroolefin, by using a mixed refrigerant containing the
hydrofluoroolefin having a carbon-carbon double bond as the primary
component and the hydrofluorocarbons having no double bond. Thus,
the amount of the tetrafluoropropene in the refrigerant sealed
therein, including the case of a single refrigerant, may be
selected arbitrarily according to the applications such as the
cooling cycle apparatus into which the compressor is incorporated
and the conditions such as the restriction on GWP described
above.
[0030] It is possible in this way to minimize the influence on
global warming as much as possible, even when the unrecovered
refrigerant is discharged into air. The mixed refrigerant at the
rate above has a smaller temperature difference and a behavior
closer to a pseudo-azeotropic mixed refrigerant, even though it is
a non-azeotropic mixed refrigerant, and thus, can improve the
cooling capacity and the cooling capacity coefficient (COP) of the
cooling cycle apparatus.
[0031] In the refrigeration cycle apparatus in the configuration
above, the refrigerant is converted to liquid by pressurization and
cooling and to gas by depressurization and heating. The compressor
61, which is driven by a motor, pressurizes a low-temperature
low-pressure gas refrigerant into a high temperature high-pressure
gas refrigerant and feeds the gas into the condenser 62. The gas is
condensed in the condenser 62, as it is cooled by air blown for
example from a fan, and gives a low-temperature high-pressure
liquid refrigerant. The liquid refrigerant is depressurized by the
throttling mechanism 63, giving partially a low-temperature
low-pressure gas refrigerant and a low-temperature low-pressure
liquid refrigerant, and feeds the liquid refrigerant into the
vaporizer 64. The liquid refrigerant is vaporized in the vaporizer
64, as heated by air blown for example form a fan, giving a
low-temperature low-pressure gas refrigerant, which is then
suctioned into the compressor 61 and pressurized therein. In this
way, liquefaction and gasification is repeated therein in the cycle
described above.
[0032] Although the refrigerating apparatus was described as a
refrigeration cycle apparatus primarily for air conditioning in the
embodiment above, it is of course possible to operate it as a
heating cycle apparatus for example by using a four-way valve.
[0033] FIG. 2 is a vertical crosssectional view of the rotary
compressor used in the refrigeration cycle apparatus shown in FIG.
1. A stator 2a of a motor 2 is connected to the upper region of a
tightly sealed container 1, and a compression mechanism unit 5
having a shaft 4 driven by a rotor 2b is connected to the lower
region of the tightly sealed container 1. A top bearing 7 is
connected to the top end of the cylinder 6 of the compression
mechanism unit 5 and a bottom bearing 8 to the bottom end thereof,
for example with screws. In the cylinder 6, a piston 9 is inserted
into the eccentric region 4a of the shaft 4 for eccentric
revolution. In addition, a refrigeration oil is stored in the
bottom region of the tightly sealed container 1, and the
refrigeration oil is desirably an oil miscible with the refrigerant
and contains at least one oxygen-containing organic compound
selected from the group consisting of polyoxyalkylene glycols,
polyvinylethers, copolymers of poly(oxy)alkylene glycols or the
monoethers thereof and polyvinylether, polyol esters and
polycarbonates as the principal component, and additionally, as
needed, various additives such as extreme-pressure lubricants,
oils, antioxidants, acid scavengers and antifoams are added.
However, in small-scale cooling cycle apparatuses such as home air
conditioners, it is practically possible to use a refrigeration oil
not miscible with the refrigerant, such as alkylbenzene or
.alpha.-olefin, if the flow rate of the refrigerant in piping is
high enough.
[0034] FIG. 3 is a crosssectional view of the compression mechanism
unit of the rotary compressor shown in FIG. 2. As shown in FIG. 3,
a vane 10 is inserted into the vane groove 6a of cylinder 6 and the
circular terminal region 10a of the vane 10 is slidably connected
to the arc-shaped slot 9a on the external surface of the piston
9.
[0035] Hereinafter, the operation and action of the rotary
compressor in the configuration above will be described.
[0036] First, a mixed refrigerant gas containing a
hydrofluoroolefin having a carbon-carbon double bond as the primary
component and hydrofluorocarbons having no double bond or a single
refrigerant gas of a hydrofluoroolefin having a carbon-carbon
double bond is suctioned into a suction chamber 12 through a
suction hole 11 formed in the cylinder 6. The gas refrigerant in
the compression chamber 13 is compressed by the leftward revolution
of the piston 9 (arrow direction) and ejected through a discharge
slot 14 out of the discharge outlet (not shown in the Figure). The
compressed gas refrigerant discharged into the tightly sealed
container 1 is then fed though the gap of the motor 2 and
discharged out of a discharge pipe 15 formed in the upper region of
the tightly sealed container 1, together with the refrigeration oil
mist present in the surrounding region.
[0037] Although a high-pressure discharge pressure and a large
force by the pressure difference with the pressure in the cylinder
is applied to the rear face 10b of the vane 10 in the present
invention, the vane is in surface contact, not in conventional line
contact, with the piston and thus, is not exposed to severe
environment at high temperature caused by sliding friction, because
the circular terminal region 10a of the vane 10 is slidably
connected to the arc-shaped slot 9a formed on the external surface
of piston 9. Because the sliding face is less easily exposed to
high temperature, it is possible to reduce generation of hydrogen
fluoride by decomposition of the mixed refrigerant gas containing a
hydrofluoroolefin having a carbon-carbon double bond as the primary
component and hydrofluorocarbons having no double bond or a single
refrigerant gas of a hydrofluoroolefin having a carbon-carbon
double bond.
[0038] When the angle of the connection between the circular
terminal region 10a of the vane 10 and the arc-shaped slot 9a on
the external surface of the piston 9 is 180.degree. or more, it is
possible to suppress separation of the connecting parts and also
can expand the contact area, thus reducing the surface pressure and
the temperature rise by sliding.
[0039] Further because the rotary compressor of the refrigeration
cycle apparatus according to the present invention is different
only, mainly in the shape of the vane and the piston from
conventional rotary compressors, and thus, it is possible to
produce it cost-effectively without major alteration of production
facility.
INDUSTRIAL APPLICABILITY
[0040] As described above, the rotary compressor according to the
present invention can assure the reliability of the refrigeration
cycle apparatus, even when a mixed refrigerant containing a
hydrofluoroolefin having a carbon-carbon double bond as the primary
component and hydrofluorocarbons having no double bond is used, and
thus, can be used in applications such as water-heating
apparatuses, car air-conditioning units, refrigeration cycles and
dehumidifier systems.
* * * * *