U.S. patent application number 11/342826 was filed with the patent office on 2006-08-03 for refrigerating device and refrigerator.
This patent application is currently assigned to SANYO ELECTRIC CO., LTD.. Invention is credited to Satoshi Imai, Hiroyuki Itsuki, Hiroshi Mukaiyama, Masahisa Otake.
Application Number | 20060168997 11/342826 |
Document ID | / |
Family ID | 36118319 |
Filed Date | 2006-08-03 |
United States Patent
Application |
20060168997 |
Kind Code |
A1 |
Imai; Satoshi ; et
al. |
August 3, 2006 |
Refrigerating device and refrigerator
Abstract
An object is to provide a refrigerating device capable of
realizing a high-efficiency operation and a refrigerator provided
with the refrigerating device in a case where a compressor having
an intermediate-pressure portion is applied, the refrigerating
device comprises a compressor having an intermediate-pressure
portion; a radiator connected to the compressor on a discharge
side; and a heat absorbing unit connected to the radiator on an
outlet side and including a pressure reducing unit and a heat sink,
the heat absorbing unit on the outlet side is connected to a
suction portion having a pressure which is lower than that of the
intermediate-pressure portion of the compressor, a refrigerant pipe
of the radiator on the outlet side is branched, one refrigerant
pipe is connected to the heat absorbing unit, the other refrigerant
pipe is connected to the intermediate-pressure portion of the
compressor, and provided with a pressure reducing mechanism and a
heat exchanger, and this heat exchanger is constituted in such a
manner that heat is exchangeable between a refrigerant of the one
refrigerant pipe and a refrigerant of the other refrigerant
pipe.
Inventors: |
Imai; Satoshi; (Ota-shi,
JP) ; Itsuki; Hiroyuki; (Ora-gun, JP) ;
Mukaiyama; Hiroshi; (Ora-gun, JP) ; Otake;
Masahisa; (Ora-gun, JP) |
Correspondence
Address: |
MCDERMOTT WILL & EMERY LLP
600 13TH STREET, N.W.
WASHINGTON
DC
20005-3096
US
|
Assignee: |
SANYO ELECTRIC CO., LTD.
|
Family ID: |
36118319 |
Appl. No.: |
11/342826 |
Filed: |
January 31, 2006 |
Current U.S.
Class: |
62/513 ;
62/510 |
Current CPC
Class: |
F25B 1/10 20130101; F25D
11/022 20130101; F25B 2309/06 20130101; F25B 2400/05 20130101; F25B
2400/13 20130101; F25B 5/02 20130101; F25B 9/008 20130101; F25B
2600/2511 20130101; F25B 41/37 20210101; F25B 2309/061 20130101;
F25B 40/00 20130101 |
Class at
Publication: |
062/513 ;
062/510 |
International
Class: |
F25B 1/10 20060101
F25B001/10; F25B 41/00 20060101 F25B041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2005 |
JP |
JP2005-024057 |
Claims
1. A refrigerating device comprising: a compressor having an
intermediate-pressure portion; a radiator connected to the
compressor on a discharge side; and heat absorbing means connected
to the radiator on an outlet side and including pressure reducing
means and a heat sink, the heat absorbing means on the outlet side
being connected to a suction portion having a pressure which is
lower than that of the intermediate-pressure portion of the
compressor, wherein a refrigerant pipe of the radiator on the
outlet side is branched, one refrigerant pipe is connected to the
heat absorbing means, the other refrigerant pipe is connected to
the intermediate-pressure portion of the compressor, and provided
with a pressure reducing mechanism and a heat exchanger, and this
heat exchanger is constituted in such a manner that heat is
exchangeable between a refrigerant of the one refrigerant pipe and
a refrigerant of the other refrigerant pipe.
2. The refrigerating device according to claim 1, further
comprising: a first heat exchanger constituted in such a manner
that the refrigerant between the heat absorbing means and the
suction portion of the compressor is heat-exchangeable with the
refrigerant of the one refrigerant pipe extended from the heat
exchanger.
3. The refrigerating device according to claim 1 or 2, wherein the
heat absorbing means comprises: first heat absorbing means
including first pressure reducing means and a first heat sink; and
second heat absorbing means including second pressure reducing
means disposed in parallel with the first heat absorbing means and
a second heat sink, and the first and second heat absorbing means
are combined with each other on the outlet side, and connected to
the suction portion of the compressor.
4. The refrigerating device according to claim 3, further
comprising: a first heat exchanger for exchanging heat between the
refrigerant discharged from the first heat sink and the refrigerant
of the one refrigerant pipe between the heat exchanger and the
first pressure reducing means; and a second heat exchanger for
exchanging heat between the refrigerant discharged from the second
heat sink and the refrigerant of the one refrigerant pipe between
the heat exchanger and the second pressure reducing means.
5. The refrigerating device according to claim 3, further
comprising: a fourth heat exchanger for exchanging heat between the
refrigerant of the one refrigerant pipe extended from the heat
exchanger and the refrigerant discharged from the first heat sink,
the one refrigerant pipe extended from the fourth heat exchanger
being connected to the first and second heat absorbing means; and a
fifth heat exchanger for exchanging heat between the refrigerant of
the one refrigerant pipe extended from the fourth heat exchanger
and that is connected to the second heat absorbing means and the
refrigerant discharged from the second heat sink, the refrigerant
pipe extended from the first heat sink and the fourth heat
exchanger being combined with the refrigerant pipe extended from
the second heat sink and the fifth heat exchanger, the combined
refrigerant pipe being connected to the suction portion of the
compressor.
6. The refrigerating device according to claims 3 to 5, wherein the
first and second heat absorbing means function in selectively
different temperature zones.
7. The refrigerating device according to claim 6, wherein the
second heat absorbing means functions in a temperature zone which
is lower than that of the first heat absorbing means.
8. A refrigerator comprising: the refrigerating device according to
claims 1 to 7.
9. The refrigerator according to claim 8, further comprising: a
refrigerating room; and a freezing room operated at a temperature
which is lower than that of the refrigerating room, the
refrigerating room being cooled by the first heat absorbing means,
the freezing room being cooled by the second heat absorbing
means.
10. The refrigerator according to claim 9, wherein the refrigerant
is circulated in the first and second heat absorbing means in a
case where the refrigerating room and/or the freezing room is at a
temperature which is not less than a predetermined temperature.
11. The refrigerating device according to claims 1 to 7 and the
refrigerator according to claims 8 to 10, wherein carbon dioxide is
used as a refrigerant.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a refrigerating device
provided with a heat exchanger for cooling a refrigerant discharged
from a radiator, and a refrigerator provided with this
refrigerating device.
[0002] In general, a refrigerating device is known which has a
refrigerating cycle provided with a compressor, a radiator, a heat
sink and the like and which cools a target to be cooled in the heat
sink.
[0003] As one example of such refrigerating device, for example, in
Japanese Patent Application Laid-Open No. 2000-230767, a
refrigerator is disclosed in which the compressor and a condenser
are combined and in which two heat sinks are connected in parallel
to each other and which switches the heat sinks to cool a freezing
room and a refrigerating room independently of each other.
[0004] Additionally, in this type of refrigerating device, there is
sometimes applied a compressor having an intermediate-pressure
portion, for example, a compressor having a multistage compression
mechanism.
[0005] In a case where the compressor having such
intermediate-pressure portion is applied to the refrigerating
device or the refrigerator as described above, when the
refrigerating cycle suitable for use in the intermediate-pressure
portion is constructed, it is sometimes possible to realize the
refrigerating device which can be operated with a high
efficiency.
SUMMARY OF THE INVENTION
[0006] An object of the present invention is to provide a
refrigerating device capable of realizing a high-efficiency
operation and a refrigerator provided with this refrigerating
device in a case where a compressor having an intermediate-pressure
portion is applied.
[0007] In a first aspect of the present invention, a refrigerating
device comprises a compressor having an intermediate-pressure
portion; a radiator connected to this compressor on a discharge
side; and heat absorbing means connected to the radiator on an
outlet side and including pressure reducing means and a heat sink,
the heat absorbing means on the outlet side being connected to a
suction portion having a pressure which is lower than that of the
intermediate-pressure portion of the compressor, wherein a
refrigerant pipe of the radiator on the outlet side is branched,
one refrigerant pipe is connected to the heat absorbing means, the
other refrigerant pipe is connected to the intermediate-pressure
portion of the compressor, and provided with a pressure reducing
mechanism and a heat exchanger, and this heat exchanger is
constituted in such a manner that heat is exchangeable between a
refrigerant of the one refrigerant pipe and a refrigerant of the
other refrigerant pipe.
[0008] In a second aspect of the present invention, the
refrigerating device of the first aspect of the present invention
further comprises a first heat exchanger constituted in such a
manner that the refrigerant between the heat absorbing means and
the suction portion of the compressor is heat-exchangeable with the
refrigerant of the one refrigerant pipe extended from the heat
exchanger.
[0009] In a third aspect of the present invention, in the
refrigerating device of the first or second aspect of the present
invention, the heat absorbing means comprises first heat absorbing
means including first pressure reducing means and a first heat
sink; and second heat absorbing means including second pressure
reducing means disposed in parallel with the first heat absorbing
means and a second heat sink, and the first and second heat
absorbing means are combined with each other on the outlet side,
and connected to the suction portion of the compressor.
[0010] In a fourth aspect of the present invention, the
refrigerating device of the third aspect of the present invention
further comprises a first heat exchanger for exchanging heat
between the refrigerant discharged from the first heat sink and the
refrigerant of the one refrigerant pipe between the heat exchanger
and the first pressure reducing means; and a second heat exchanger
for exchanging heat between the refrigerant discharged from the
second heat sink and the refrigerant of the one refrigerant pipe
between the heat exchanger and the second pressure reducing
means.
[0011] In a fifth aspect of the present invention, the
refrigerating device of the third aspect of the present invention
further comprises a fourth heat exchanger for exchanging heat
between the refrigerant of the one refrigerant pipe extended from
the heat exchanger and the refrigerant discharged from the first
heat sink, the one refrigerant pipe extended from the fourth heat
exchanger being connected to the first and second heat absorbing
means; and a fifth heat exchanger for exchanging heat between the
refrigerant of the one refrigerant pipe extended from the fourth
heat exchanger and that is connected to the second heat absorbing
means and the refrigerant discharged from the second heat sink, the
refrigerant pipe extended from the first heat sink and the fourth
heat exchanger being combined with the refrigerant pipe extended
from the second heat sink and the fifth heat exchanger, the
combined refrigerant pipe being connected to the suction portion of
the compressor.
[0012] In a sixth aspect of the present invention, in the
refrigerating device of the third to fifth aspects of the present
invention, the first and second heat absorbing means function in
selectively different temperature zones.
[0013] In a seventh aspect of the present invention, in the
refrigerating device of the sixth aspect of the present invention,
the second heat absorbing means functions in a temperature zone
which is lower than that of the first heat absorbing means.
[0014] In an eighth aspect of the present invention, a refrigerator
comprises the refrigerating device of the first to seventh aspects
of the present invention.
[0015] In a ninth aspect of the present invention, the refrigerator
of the eighth aspect of the present invention further comprises a
refrigerating room; and a freezing room operated at a temperature
which is lower than that of the refrigerating room, the
refrigerating room being cooled by the first heat absorbing means,
the freezing room being cooled by the second heat absorbing
means.
[0016] In a tenth aspect of the present invention, in the
refrigerator of the ninth aspect of the present invention, the
refrigerant is circulated through the first and second heat
absorbing means in a case where the refrigerating room and/or the
freezing room is at a temperature which is not less than a
predetermined temperature.
[0017] In an eleventh aspect of the present invention, carbon
dioxide is used as a refrigerant in the refrigerating device of the
first to seventh aspects of the present invention, and the
refrigerator of the eighth to tenth aspects of the present
invention.
[0018] According to the present invention, there is disposed a heat
exchange circuit which super-cools the refrigerant discharged from
the radiator to thereby provide the refrigerating device capable of
operating with a high efficiency. Furthermore, according to the
present invention, there is provided a refrigerator capable of
operating with the high efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a refrigerant circuit diagram showing one
embodiment of a refrigerating device in the present invention;
[0020] FIG. 2 is an enthalpy-pressure chart of a refrigerating
cycle in one embodiment of the refrigerating device of the present
invention;
[0021] FIG. 3 is a schematic constitution diagram showing an
application example of the refrigerating device to a refrigerator
in one embodiment of the present invention;
[0022] FIG. 4 is a refrigerant circuit diagram showing another
embodiment of the refrigerating device in the present
invention;
[0023] FIG. 5 is a refrigerant circuit diagram showing still
another embodiment of the refrigerating device in the present
invention; and
[0024] FIG. 6 is a refrigerant circuit diagram showing a fourth
embodiment of the refrigerating device in the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] There will be described hereinafter preferred embodiments of
a refrigerating device and a refrigerator provided with the
refrigerating device in the present invention in detail with
reference to the drawings.
Embodiment 1
[0026] One embodiment of the present invention will be described in
detail with reference to the drawings. FIG. 1 shows a refrigerant
circuit diagram of a refrigerating device as one embodiment of the
present invention. A refrigerating device 30 is constituted of a
compressor 1; a radiator 2 connected to this compressor 1 on a
discharge side; first heat absorbing means 10 connected to the
radiator 2 on an outlet side; second heat absorbing means 11
disposed in parallel with the first heat absorbing means 10; and a
heat exchange circuit 20. The first heat absorbing means 10 and the
second heat absorbing means 11 on the outlet side are connected to
the compressor 1 on a suction side, and the heat exchange circuit
20 on the outlet side is connected to an intermediate-pressure
portion of the compressor 1 to constitute a refrigerating
cycle.
[0027] The first heat absorbing means 10 includes a first expansion
valve 65 in which a refrigerant from a branch point 9A circulates;
and a refrigerating heat sink 57. The second heat absorbing means
11 is disposed in parallel with the first heat absorbing means 10
as described above, and includes a second expansion valve 66 in
which the refrigerant from the branch point 9A circulates; a
freezing heat sink 58; and a check valve 52.
[0028] The first heat absorbing means 10 and the second heat
absorbing means 11 function in mutually selectively different
temperature zones. A refrigerant pipe from the radiator 2 is
branched from the branch point 9A into one pipe as the first heat
absorbing means 10 and the other pipe as the second heat absorbing
means 11. The pipes connected in parallel with each other are again
combined at a junction 9B which is disposed before a suction port
of the compressor 1.
[0029] Here, the first and second expansion valves 65 and 66 are
constituted in such a manner that a throttle degree is variable.
This throttle degree is changed to lower a refrigerant pressure to
a predetermined pressure before the refrigerant reaches the heat
sinks 57, 58, and it is possible to control an evaporation
temperature of the refrigerant in the heat sinks 57, 58. Moreover,
one of the first and second expansion valves 65 and 66 is totally
closed to thereby selectively circulate the refrigerant in the
first heat absorbing means 10 or the second heat absorbing means
11.
[0030] Moreover, in the present embodiment, the refrigerating
device 30 is provided with a check valve 53 and a third heat
exchanger 19 between the junction 9B of the first and second heat
absorbing means 10 and 11 and the suction side of the compressor 1.
The third heat exchanger is disposed in such a manner that heat is
exchangeable between the refrigerant discharged from the first and
second heat sinks 57, 58 and the refrigerant before the branch
point 9A.
[0031] Among the refrigerants branched from a branch point 9C on
the outlet side of the radiator 2, the refrigerant which does not
circulate in the first and second heat absorbing means 10 and 11
circulates in the heat exchange circuit 20. The heat exchange
circuit includes a third expansion valve 31 and a cooling heat
exchanger 32. The cooling heat exchanger 32 on the outlet side is
connected to a refrigerant introducing tube 6 for introducing the
refrigerant discharged from the cooling heat exchanger 32 to the
intermediate-pressure portion of the compressor 1, and this
refrigerant introducing tube 6 is provided with a check valve 7. It
is to be noted that the third expansion valve 31 is constituted in
such a manner that the throttle degree is variable in the same
manner as in the first and second expansion valves 65 and 66. The
throttle degree of the third expansion valve 31 is changed to lower
the pressure to the predetermined pressure before the refrigerant
reaches the cooling heat exchanger 32. The refrigerant discharged
from the third expansion valve 31 exchanges heat with the
refrigerant reaching the first and second heat absorbing means 10
and 11 from the branch point 9C in the cooling heat exchanger 32,
and is warmed to constitute a gas refrigerant. The refrigerant is
returned to the intermediate-pressure portion of the compressor 1
via the refrigerant introducing tube 6.
[0032] The compressor 1 is a two-stage compressor including a
first-stage compression portion 1A and a second-stage compression
portion 1B in a sealed container. An intermediate cooling unit 1C
is disposed in a refrigerant pipe constituting the first-stage
compression portion 1A to the second-stage compression portion 1B
outside the sealed container. The refrigerant introducing tube 6 is
connected in such a manner that the gas refrigerant discharged from
the cooling heat exchanger 32 can be introduced into the
intermediate-pressure portion of the compressor 1, that is, between
the intermediate cooling unit 1C and the second-stage compression
portion 1B. It is to be noted that the gas refrigerant discharged
from the cooling heat exchanger 32 is introduced into the
intermediate-pressure portion of the compressor 1 owing to a
difference pressure in the refrigerant introducing tube 6 as shown
by a broken-line arrow, but the compressor 1 is not limited to the
two-stage compressor. For example, when a single-stage compressor
is used as the compressor, the refrigerant introducing tube 6 may
return to the intermediate-pressure portion of the single-stage
compressor. A plurality of compressors may be connected.
[0033] Moreover, since the first and second heat absorbing means 10
and 11 are constituted as described above, the refrigerant
circulates on the side of the heat sink 57, that is, in the first
heat absorbing means 10 only, for example, in a case where the
second expansion valve 66 is closed and the first expansion valve
65 is opened. Conversely, when the first expansion valve 65 is
closed and the second expansion valve 66 is opened, the refrigerant
circulates on the side of the heat sink 58, that is, in the second
heat absorbing means 11 only.
[0034] Here, after the refrigerant discharged from the heat sink 57
passes through the check valve 53, the refrigerant passes through
the third heat exchanger 19. After exchanging heat with the
refrigerant discharged from the cooling heat exchanger 32 in the
third heat exchanger 19, the refrigerant is returned to the suction
port of the compressor 1. The refrigerant passed through the heat
sink 58 passes through the check valves 52, 53 and then the third
heat exchanger 19. After exchanging heat with the refrigerant
discharged from the cooling heat exchanger 32 in the third heat
exchanger 19, the refrigerant is returned to the suction port of
the compressor 1.
[0035] Further in the present embodiment, cold air passed through
the heat sink 57 is fed to a refrigerating room 21 via a duct 57A,
and cold air passed through the heat sink 58 is fed to a freezing
room 22 via a duct 58A.
[0036] Here, in the refrigerating device 30 of the present
embodiment, as the refrigerant, there is used a carbon dioxide
refrigerant (CO.sub.2) which is a natural refrigerant having a
small environmental load in consideration of flammability, toxicity
and the like. As oil which is a lubricant of the radiator 2, there
is used, for example, mineral oil, alkyl benzene oil, ether oil,
ester oil, polyalkylene glycol (PAG), polyol ester (POE) or the
like.
[0037] There will be described an operation of the refrigerating
device 30 of the present embodiment constituted as described above
with reference to FIGS. 1 and 2. FIG. 2 is an enthalpy-pressure
(ph) chart of a refrigerating cycle in the present embodiment.
[0038] First, a freezing operation (e.g., around -26.degree. C.)
will be described with reference to the cycle graph shown by a
solid line in FIG. 2. It is to be noted that this freezing
operation refers to a case where the refrigerant is circulated on
the side of the heat sink 58, that is, in the second heat absorbing
means 11. In the present embodiment, when the compressor 1 is
operated, the refrigerant discharged from the compressor 1 radiates
heat in the radiator 2, and is cooled. That is, the refrigerant is
circulated in order: (1) suction into the first-stage compression
portion 1A; (2) discharge from the first-stage compression portion
1A; (3) suction into the second-stage compression portion 1B; and
(4) discharge from the second-stage compression portion 1B.
Thereafter, the refrigerant flows from (5) an outlet of the
radiator 2 to the branch point 9C. The refrigerant is then
branched, a part of the refrigerant circulates in the heat exchange
circuit 20, and the remaining refrigerant circulates in the second
heat absorbing means 11.
[0039] The refrigerant circulated from the branch point 9C to the
heat exchange circuit 20 reaches (6) an outlet of the third
expansion valve 31 to form a two-phase mixture of gas and liquid.
Moreover, this refrigerant as the two-phase mixture exchanges heat
with the refrigerant circulated from the branch point 9C to the
second heat absorbing means 11 in the cooling heat exchanger 32,
and is warmed to form the gas refrigerant. The refrigerant is
introduced into the intermediate-pressure portion of the compressor
1, that is, between the intermediate cooling unit 1C and the
second-stage compression portion 1B. That is, (6) indicates the
outlet of the third expansion valve 31, and an inlet to the cooling
heat exchanger 32, and (21) indicates the outlet of the cooling
heat exchanger 32. The refrigerant discharged from the cooling heat
exchanger reaches (3) the suction port to the second-stage
compression portion 1B, and is compressed in the second-stage
compression portion 1B.
[0040] On the other hand, the refrigerant circulated from the
branch point 9C to the second heat absorbing means 11 exchanges
heat with the refrigerant circulated on the side of the heat
exchange circuit 20 as described above, and is super-cooled.
Thereafter, the refrigerant is further cooled, and branched at the
branch point 9A to reach the second expansion valve 66. (18)
indicates the outlet of the cooling heat exchanger 32 and the inlet
to the third heat exchanger 19, (7) indicates the outlet of the
third heat exchanger 19 and the inlet to the second expansion valve
66, (8) indicates the outlet of the second expansion valve 66, and
(22) indicates the outlet of the heat sink 58. A liquid refrigerant
that has entered the heat sink 58 evaporates to absorb heat from
the periphery. Thereafter, after exchanging heat with the
refrigerant discharged from the cooling heat exchanger 32 in the
third heat exchanger 19, the refrigerant returns to the suction
port of the compressor 1. That is, (23) indicates the outlet of the
third heat exchanger 19, and (1) indicates the suction into the
first-stage compression portion 1A.
[0041] On the other hand, during a refrigerating operation (e.g.,
around -5.degree. C.), there is formed a cycle shown by a broken
line in FIG. 2. It is to be noted that this refrigerating operation
refers to a case where the refrigerant is circulated on the side of
the heat sink 57, that is, in the first heat absorbing means 10.
Also in this case, when the compressor 1 is operated, the
refrigerant discharged from the compressor 1 radiates heat in the
radiator 2, and is cooled. That is, first the refrigerant is
circulated in order: (9) suction into the first-stage compression
portion 1A; (10) discharge from the first-stage compression portion
1A; (11) discharge from the intermediate cooling unit 1C and
suction into the second-stage compression portion 1B; and (12)
discharge from the second-stage compression portion 1B. Thereafter,
the refrigerant flows from (5) the outlet of the radiator 2 to
reach the branch point 9C, and is then branched. A part of the
refrigerant circulates in the heat exchange circuit 20, and the
remaining refrigerant circulates in the first heat absorbing means
10.
[0042] The refrigerant circulated from the branch point 9C to the
heat exchange circuit 20 reaches (16) the outlet of the third
expansion valve 31 to form a two-phase mixture of gas and liquid.
Moreover, this refrigerant as the two-phase mixture exchanges heat
with the refrigerant circulated from the branch point 9C to the
first heat absorbing means 10 in the cooling heat exchanger 32, and
is warmed to constitute a gas refrigerant. The refrigerant is
introduced into the intermediate-pressure portion of the compressor
1, that is, between the intermediate cooling unit 1C and the
second-stage compression portion 1B. That is, (16) indicates the
outlet of the third expansion valve 31 and the inlet to the cooling
heat exchanger 32, and (17) indicates the outlet of the cooling
heat exchanger 32. The refrigerant discharged from the cooling heat
exchanger reaches (12) the suction port of the second-stage
compression portion 1B, and is compressed in the second-stage
compression portion 1B.
[0043] On the other hand, the refrigerant circulated from the
branch point 9C to the first heat absorbing means 10 exchanges heat
with the refrigerant circulated on the side of the heat exchange
circuit 20 in the cooling heat exchanger 32 as described above, and
is super-cooled. Thereafter, the refrigerant is further cooled in
the third heat exchanger 19, and branched at the branch point 9A to
reach the first expansion valve 65. (13) indicates the outlet of
the cooling heat exchanger 32 and the inlet to the third heat
exchanger 19, (14) indicates the outlet of the third heat exchanger
19 and the inlet to the first expansion valve 65, (15) indicates
the outlet of the first expansion valve 65, and (24) indicates the
outlet of the heat sink 57. After the liquid refrigerant which has
entered the heat sink 57 evaporates to absorb heat from the
periphery, the refrigerant exchanges heat with the refrigerant
discharged from the cooling heat exchanger 32 in the third heat
exchanger 19, and the refrigerant returns to the suction port of
the compressor 1. That is, (25) indicates the outlet of the third
heat exchanger 19, and (9) indicates the suction into the
first-stage compression portion 1A. The refrigerant circulates and
changes its state to form the refrigerating cycle as described
above during both the freezing operation and the refrigerating
operation.
[0044] Moreover, in the present embodiment, since the carbon
dioxide refrigerant is introduced into the refrigerant circuit, a
dry degree of the refrigerant entering the expansion valves 65, 66
is excessively high in the refrigerant circuit for use in a
conventional chlorofluorocarbon-based refrigerant or HC-based
refrigerant, that is, the refrigerant circuit in which the
expansion valves 65, 66 are disposed immediately after the radiator
2 even in a case where the atmospheric temperature around the
radiator 2, that is, the temperature in (5) the outlet of the
radiator 2 in FIG. 2 is about +22.degree. C. as in the present
embodiment. Therefore, a ratio of the gas refrigerant in the
refrigerant is high, and it is difficult to obtain a sufficient
cooling performance.
[0045] To solve the problem, in the present embodiment, the
refrigerant pipe on the side of the outlet of the radiator 2 is
branched, and one pipe is provided with the heat exchange circuit
20 to super-cool the refrigerant which has entered the first and
second heat absorbing means 10 and 11 in the cooling heat exchanger
32 of the heat exchange circuit 20. The refrigerant is further
cooled in the third heat exchanger 19. According to such
constitution, a high cooling effect can be obtained even in a case
where the carbon dioxide refrigerant having the above-described
characteristics is used. In this case, the refrigerant on the side
of the heat exchange circuit 20 is introduced as the gas
refrigerant into the intermediate-pressure portion of the
compressor 1. Therefore, a compression efficiency in the compressor
1 can be improved, and an efficiency of the refrigerating device 30
can further be improved.
[0046] Moreover, during the freezing operation, the refrigerant
entering the second heat absorbing means 11 needs to be
super-cooled as compared with the refrigerating operation. However,
in the present embodiment, the degree of throttle of the third
expansion valve 31 is variable in the heat exchange circuit 20 as
described above. Therefore, during the freezing operation, more
super-cooling can be achieved as compared with the refrigerating
operation. Furthermore, during the freezing operation, there is
used the heat sink 58 which functions in a temperature zone lower
than that of the refrigerating heat sink 57. In consequence a
higher-efficiency freezing operation can be performed.
[0047] As described above in detail, in the present embodiment, the
heat exchange circuit 20 is disposed, and the heat sinks 57, 58 are
selectively used based on the use temperature zone. According to
this constitution, the heat sink suitable at the temperature is
usable during the freezing operation and the refrigerating
operation which are different from each other in temperature zone,
and improvement of each operation efficiency can be expected.
[0048] Next, there will be described an example in which the
refrigerating device 30 of the present embodiment is applied to a
refrigerator with reference to FIG. 3.
[0049] FIG. 3 shows a schematic constitution diagram of the
refrigerator provided with the refrigerating device 30 of the
present embodiment. This refrigerator 40 is constituted of a
refrigerating room 41 disposed in an upper stage; and a freezing
room 42 disposed in a lower stage. Moreover, refrigerator partition
walls 61, 62 are disposed in inner parts of the respective rooms
41, 42, and the heat sinks 57, 58 and fans 63, 64 are disposed in
air paths 44 defined by the refrigerator partition walls 61, 62. In
the present constitution, the first heat absorbing means 10 and the
second heat absorbing means 11 are switched as described above when
a thermostat turns on and off during the refrigerating operation
and the freezing operation. Accordingly, the refrigerant is passed
through one of the heat sinks 57, 58, and the corresponding fan 63
or 64 is driven. When the refrigerant flows through the heat sink
57, cold air is supplied to the refrigerating room 41. When the
refrigerant flows through the heat sink 58, cold air is supplied to
the freezing room 42.
[0050] As described above, in the present embodiment, since the
refrigerator 40 is provided with the refrigerating device 30, it is
possible to obtain a high cooling performance and a high-efficiency
operation even in a case where carbon dioxide is used as the
refrigerant.
[0051] It is to be noted that as described above, in the present
embodiment, in the refrigerating device 30, the first expansion
valve 65 is closed and the second expansion valve 66 is opened to
circulate the refrigerant in the second heat absorbing means 11
during the freezing operation. During the refrigerating operation,
the second expansion valve 66 is closed, and the first expansion
valve 65 is opened to circulate the refrigerant in the first heat
absorbing means 10. However, the present invention is not limited
to this embodiment. For example, in the refrigerator 40, in a case
where the refrigerating room 41 and the freezing room 42 need to be
cooled rapidly at normal temperature, during so-called pull-down,
in a case where the compressor 1 brought in an operation stopped
state is started to operate, at a high-load time, or in a case
where the refrigerating room 41 and the freezing room 42 are at a
temperature which is not less than a predetermined temperature,
both of the first expansion valve 65 and the second expansion valve
66 are opened at required open degrees. Accordingly, the
refrigerant can be circulated in both of the first heat absorbing
means 10 and the second heat absorbing means 11 to rapidly cool the
insides of the respective rooms 41, 42.
Embodiment 2
[0052] Next, another embodiment of the present invention will be
described with reference to FIG. 4. FIG. 4 shows a refrigerant
circuit diagram of a refrigerating device 50 in this case. The
present embodiment is different from Embodiment 1 in that first and
second heat exchangers 17, 18 are disposed instead of a third heat
exchanger 19. That is, in the present embodiment, refrigerants
discharged from the heat sinks 57, 58 exchange heat with
refrigerants that are to enter first and second expansion valves
65, 66 before the refrigerants are combined at a junction 9B.
Needless to say, the refrigerating device 50 of the present
embodiment can be applied to a refrigerator in the same manner as
in the refrigerating device 30 of Embodiment 1 described above.
Embodiment 3
[0053] Next, still another embodiment of the present invention will
be described with reference to FIG. 5. FIG. 5 shows a refrigerant
circuit diagram of a refrigerating device 70 in this case. The
present embodiment is different from Embodiment 1 in that a third
heat exchanger 19 is not disposed, first a refrigerant discharged
from a cooling heat exchanger 32 exchanges heat with a refrigerant
discharged from a heat sink 57 in a fourth heat exchanger 15 before
reaching a branch point 9A, and an only refrigerant entering second
heat absorbing means 11 exchanges heat with a refrigerant
discharged from a heat sink 58 in a fifth heat exchanger 16.
[0054] It is to be noted that, needless to say, even the
refrigerating device 70 of the present embodiment can be applied to
a refrigerator in the same manner as in the refrigerating device of
each of the above-described embodiments.
Embodiment 4
[0055] Next, a fourth embodiment of the present invention will be
described with reference to FIG. 6. FIG. 6 shows a refrigerant
circuit diagram of a refrigerating device 90 in this case. The
present embodiment is different from Embodiment 1 in that a
three-way valve 91 is disposed in place of a branch point 9A, and
third and fourth heat absorbing means 10B, 11B are disposed instead
of first and second heat absorbing means 10, 11.
[0056] The third heat absorbing means 10B includes a first
capillary tube 92 and a heat sink 57, and the fourth heat absorbing
means 11B includes a second capillary tube 93 and a heat sink
58.
[0057] In the present embodiment, the refrigerating device 90
selects, via the three-way valve 91, whether to circulate a
refrigerant in the third heat absorbing means 10B or the fourth
heat absorbing means 11B so that a refrigerating operation or a
freezing operation can be selected. As described above, since the
capillary tubes 92, 93 are used instead of expansion valves 65, 66
in the respective heat absorbing means in the refrigerating device
90 of the present embodiment, it is possible to realize the
refrigerating device of the present invention at a lower cost.
[0058] It is to be noted that even in the refrigerating devices 50,
70 of Embodiments 2, 3, it is possible to apply the third and
fourth heat absorbing means 10B, 11B as in the present embodiment.
Needless to say, even the refrigerating device 90 of the present
embodiment can be applied to a refrigerator in the same manner as
in the refrigerating device of each of the above-described
embodiments.
[0059] The present invention has been described above in accordance
with the respective embodiments, but the present invention is not
limited to the embodiments, and can variously be modified or
embodied. For example, in the above-described embodiments, the
carbon dioxide refrigerant is introduced in the refrigerant
circuit, but the present invention is not limited to this
embodiments, and can be applied to a refrigerant circuit into which
another refrigerant such as a chlorofluorocarbon-based refrigerant
is introduced.
[0060] Moreover, the third expansion valve 31 in each of the
above-described embodiments and the expansion valves 65, 66 of
Embodiments 1, 2, and 3 may be replaced with capillary tubes.
* * * * *