U.S. patent application number 11/080422 was filed with the patent office on 2005-09-22 for refrigerating machine.
This patent application is currently assigned to SANYO ELECTRIC CO., LTD.. Invention is credited to Imai, Satoshi, Itsuki, Hiroyuki, Kamimura, Ichiro, Mizukami, Kazuaki, Mukaiyama, Hiroshi, Nagae, Etsushi, Sugawara, Akira.
Application Number | 20050204773 11/080422 |
Document ID | / |
Family ID | 34840257 |
Filed Date | 2005-09-22 |
United States Patent
Application |
20050204773 |
Kind Code |
A1 |
Imai, Satoshi ; et
al. |
September 22, 2005 |
Refrigerating machine
Abstract
A refrigerating machine is equipped with a compressor 1, a
radiator 2, a pressure-reducing device 3, a gas-liquid separator 4,
a unit for introducing the gas refrigerant separated in gas-liquid
separator 4 into an intermediate pressure portion of the
compressor, and a low pressure side circuit 9 in which liquid
refrigerant separated in the gas-liquid separator is circulated.
The low pressure side circuit 9 is provided with a heat absorbing
unit 10 which selectively functions in different temperature zones.
When the heat absorbing unit 10 is made to function in a high
temperature zone, the gas refrigerant separated in the gas-liquid
separator 4 is inhibited from being introduced into the
intermediate pressure portion of the compressor 1 is inhibited, or
allowed to be introduced into another intermediate pressure portion
which is lower in pressure than the intermediate pressure
portion.
Inventors: |
Imai, Satoshi; (Gunma,
JP) ; Sugawara, Akira; (Saitama, JP) ;
Mukaiyama, Hiroshi; (Gunma, JP) ; Nagae, Etsushi;
(Gunma, JP) ; Itsuki, Hiroyuki; (Gunma, JP)
; Mizukami, Kazuaki; (Gunma, JP) ; Kamimura,
Ichiro; (Gunma, JP) |
Correspondence
Address: |
McDERMOTT, WILL & EMERY
600 13th Street, N.W.
Washington
DC
20005-3096
US
|
Assignee: |
SANYO ELECTRIC CO., LTD.
|
Family ID: |
34840257 |
Appl. No.: |
11/080422 |
Filed: |
March 16, 2005 |
Current U.S.
Class: |
62/512 ;
62/510 |
Current CPC
Class: |
F25B 2600/2509 20130101;
F25B 2400/23 20130101; F25B 9/008 20130101; F25D 17/045 20130101;
F25B 2600/2511 20130101; F25D 2317/0682 20130101; F25B 2309/061
20130101; F25D 11/022 20130101; F25B 2400/13 20130101; F25D 11/02
20130101; F25B 5/02 20130101; F25B 1/10 20130101; F25D 17/065
20130101; F25B 41/39 20210101; F25D 2400/04 20130101 |
Class at
Publication: |
062/512 ;
062/510 |
International
Class: |
F25B 041/00; F25B
049/00; F25B 001/10; F25B 043/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 19, 2004 |
JP |
P2004-79341 |
Mar 19, 2004 |
JP |
P2004-79342 |
Claims
What is claimed is
1. A refrigerating machine comprising: a compressor; a radiator; a
pressure-reducing device; a gas-liquid separator; a unit for
introducing gas refrigerant separated in the gas-liquid separator
into a first intermediate pressure portion of the compressor; a low
pressure side circuit in which liquid refrigerant separated in the
gas-liquid separator is circulated, the low pressure side circuit
being equipped with an absorbing unit functioning selectively in
different temperature zones; and a gas refrigerant introduction
inhibiting/allowing unit for inhibiting introduction of the gas
refrigerant separated in the gas-liquid separator into the
intermediate pressure portion of the compressor when the heat
absorbing unit is made to function in the high temperature
zone.
2. The refrigerating machine according to claim 1, wherein the gas
refrigerant introduction inhibiting/allowing unit is constructed by
an opening/closing valve.
3. The refrigerating machine according to claim 1, wherein the heat
absorbing unit is equipped with plural heat absorbers each of which
functions selectively and is equipped with a unit for guiding cold
air passed therethrough to a chamber controlled to the
corresponding temperature zone.
4. The refrigerating machine according to claim 3, wherein each of
the heat absorbers is disposed in a chamber controlled to the
corresponding temperature zone.
5. The refrigerating machine according to claim 1, wherein the heat
absorbing unit is equipped with one heat absorber which selectively
functions in different temperature zones and is equipped with a
unit for selectively guiding cold air passed therefrom through a
switching dumper to plural chambers which are respectively
controlled to different temperature zones.
6. The refrigerating machine according to claim 5, wherein the heat
absorber is disposed at a chamber controlled to a low temperature
zone.
7. The refrigerating machine according to claim 1, wherein
refrigerant with which a high voltage side is set to supercritical
pressure under operation is enclosed in a refrigerant circuit.
8. A refrigerating machine comprising: a compressor; a radiator; a
pressure-reducing device; a gas-liquid separator; a unit for
introducing gas refrigerant separated in the gas-liquid separator
into a first intermediate pressure portion of the compressor; a low
pressure side circuit in which liquid refrigerant separated in the
gas-liquid separator is circulated, the low pressure side circuit
being equipped with an absorbing unit functioning selectively in
different temperature zones; and a gas refrigerant introducing unit
for selectively introducing the gas refrigerant separated in the
gas-liquid separator into one of the first intermediate pressure
portion of the compressor any a second intermediate pressure
portion nearer to a low pressure suction port of the compressor
than the first intermediate pressure portion, wherein the gas
refrigerant introducing unit introduces the gas refrigerant
separated in the gas-liquid separator into the first intermediate
pressure portion when the heat absorbing unit is made to function
in a low temperature zone, and introduces the gas refrigerant
separated in the gas-liquid separator into the second intermediate
pressure portion of the compressor when the heat absorbing unit is
made to function in a high temperature zone.
9. The refrigerating machine according to claim 8, wherein the heat
absorbing unit is equipped with plural heat absorbers each of which
functions selectively and is equipped with a unit for guiding cold
air passed therethrough to a chamber controlled to the
corresponding temperature zone.
10. The refrigerating machine according to claim 9, wherein each of
the heat absorbers is disposed in a chamber controlled to the
corresponding temperature zone.
11. The refrigerating machine according to claim 8, wherein the
heat absorbing unit is equipped with one heat absorber which
selectively functions in different temperature zones and is
equipped with a unit for selectively guiding cold air passed
therefrom through a switching dumper to plural chambers which are
respectively controlled to different temperature zones.
12. The refrigerating machine according to claim 11, wherein the
heat absorber is disposed at a chamber controlled to a low
temperature zone.
13. The refrigerating machine according to claim 8, wherein
refrigerant with which a high voltage side is set to supercritical
pressure under operation is enclosed in a refrigerant circuit.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a refrigerating machine
having a refrigerant introducing unit for selectively introducing
gas refrigerant separated in a gas-liquid separator into an
intermediate pressure portion of a compressor.
[0003] 2. Description of the Related Art
[0004] There is generally known a refrigerating machine equipped
with a compressor, a radiator, a pressure-reducing device, a
gas-liquid separator and a refrigerant introducing unit for
selectively introducing gas refrigerant separated in the gas-liquid
separator into an intermediate pressure portion (JP-A-2003-106693).
In this type of refrigerating machine, the gas refrigerant
separated in the gas-liquid separator is introduced into an
intermediate pressure portion of the compressor while keeping the
refrigerant under gas state, so that the efficiency of the
compressor can be enhanced.
[0005] This type of refrigerating machine is equipped with a heat
absorbing unit containing a heat absorber which selectively
functions in each of different temperature zones in a refrigerating
cycle in some cases.
[0006] For example, when the refrigerating machine as described
above is applied to a refrigerator having a refrigerating chamber
and a freezing chamber, a heat absorber functioning for
refrigeration or freezing is disposed in a refrigerating cycle, and
a refrigerating or freezing operation is carried out by using the
function of any one heat absorber. In this case, it is important to
carry out the operation with high efficiency without reducing the
efficiency under any operation.
SUMMARY OF THE INVENTION
[0007] Therefore, an object of the present invention is to provide
a refrigerating machine in which when a heat absorbing unit
selectively functioning in different temperature zones is provided
in a refrigerating cycle, a high-efficiency operation can be
performed in all the temperature zones without reducing the
efficiency.
[0008] In order to attain the above object, a refrigerating machine
comprising: a compressor; a radiator; a pressure-reducing device; a
gas-liquid separator; a unit for introducing gas refrigerant
separated in the gas-liquid separator into a first intermediate
pressure portion of the compressor; a low pressure side circuit in
which liquid refrigerant separated in the gas-liquid separator is
circulated, the low pressure side circuit being equipped with an
absorbing unit functioning selectively in different temperature
zones; and a gas refrigerant introduction inhibiting/allowing
switching unit for inhibiting introduction of the gas refrigerant
separated in the gas-liquid separator into the intermediate
pressure portion of the compressor when the heat absorbing unit is
made to function in a higher temperature zone and allowing
introduction of the gas refrigerant separated in the gas-liquid
separator into a second intermediate pressure portion of the
compressor which is lower in pressure than the first intermediate
pressure portion of the compressor.
[0009] In the above refrigerating machine, a part of the gas
refrigerant introduction inhibiting/allowing switching unit may be
constructed by an opening/closing valve. Furthermore, another part
of the gas refrigerant introduction inhibiting/allowing switching
unit may be constructed by a three-way valve and a branched gas
pipe.
[0010] In the above refrigerating machine, the heat absorbing unit
may be equipped with plural heat absorbers each of which functions
selectively and is equipped with a unit for guiding cold air passed
through the heat absorber to a chamber which is controlled to the
corresponding temperature zone. The heat absorbing unit may be
equipped with one heat absorber which selectively functions in
different temperature zones and is equipped with a unit for
selectively guiding cold air passed through the heat absorber
through a switching dumper to plural chambers which are
respectively controlled to different temperature zones. The heat
absorber may be disposed at a chamber which is controlled to a low
temperature zone. In all the cases, refrigerant with which a high
voltage side is set to supercritical pressure under operation may
be filled in a refrigerant circuit.
[0011] Furthermore, the three-way valve and the branch gas pipe may
constitute gas refrigerant introducing unit which can introduce the
gas refrigerant separated in the gas-liquid separator to one of a
first intermediate pressure portion of the compressor and a second
intermediate pressure portion at a lower pressure suction side than
the first intermediate pressure portion. When the heat absorbing
unit is made to function in a low temperature zone, the gas
refrigerant separated in the gas-liquid separator is introduced to
the first intermediate pressure portion of the compressor. On the
other hand, when the heat absorbing unit is made to function in a
high temperature zone, the gas refrigerant is introduced to the
second intermediate pressure portion of the compressor.
[0012] In this case, the heat absorbing unit may be provided with
plural heat absorbers which function in different temperature
zones, and each of the heat absorbers may function selectively and
may be equipped with a unit for guiding cold air passed through the
heat absorber concerned to a chamber which is controlled to the
corresponding temperature zone. Furthermore, each of the heat
absorbers may be disposed in a chamber which is controlled to the
corresponding temperature zone.
[0013] Furthermore, the heat absorbing unit may be provided with
one heat absorber which selectively functions in different
temperature zones, and also with a unit for selectively guiding
cold air therefrom through a switching dumper to plural chambers
controlled to different temperature zones. In this case, the heat
absorber may be disposed in a chamber controlled to a low
temperature zone. In all the cases, carbon dioxide refrigerant with
which the high pressure side is set to supercritical pressure under
operation may be enclosed in the refrigerant circuit.
[0014] According to the present invention, the heat absorbing unit
which selectively functions in different temperature zones is
provided to the low pressure side circuit in which liquid
refrigerant is circulated, and the refrigerating machine is
provided with the gas refrigerant introduction inhibiting/allowing
unit for inhibiting introduction of the gas refrigerant separated
in the gas-liquid separator into the intermediate pressure portion
of the compressor when the heat absorbing unit is made to function
in a high temperature zone. Therefore, the high-efficient operation
can be performed in the respective temperature zones.
[0015] Furthermore, according to the present invention, the heat
absorbing unit which selectively functions in different temperature
zones is provided to the low pressure side circuit in which liquid
refrigerant is circulated, and the refrigerating machine is
provided with the gas refrigerant introducing unit for introducing
the gas refrigerant into the first intermediate pressure portion of
the compressor when the heat absorbing unit is made to function in
a low temperature zone, and introducing the gas refrigerant into
the second intermediate pressure portion of the compressor when the
heat absorbing unit is made to function in a high temperature zone.
Therefore, the high-efficient operation can be performed in the
respective temperature zones.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a refrigerant circuit diagram showing a first
embodiment of a refrigerating machine according to the present
invention;
[0017] FIG. 2 is an enthalpy-pressure diagram of a refrigerating
cycle;
[0018] FIG. 3 is a diagram showing an applied example to the first
embodiment to a refrigerator;
[0019] FIG. 4 is a diagram showing an applied example to a
refrigerator;
[0020] FIG. 5 is a refrigerant circuit diagram showing a
modification of the first embodiment;
[0021] FIG. 6 is a diagram showing an applied example of the
modification to a refrigerator;
[0022] FIG. 7 is a diagram showing an applied example to a
refrigerator;
[0023] FIG. 8 is a refrigerant circuit diagram showing a second
embodiment of the refrigerating machine according to the present
invention;
[0024] FIG. 9 is an enthalpy-pressure diagram showing a
refrigerating cycle;
[0025] FIG. 10 is a diagram showing an applied example of the
second embodiment to a refrigerator, and corresponds to FIG. 3;
[0026] FIG. 11 is a diagram showing an applied example to a
refrigerator and corresponds to FIG. 4;
[0027] FIG. 12 is a refrigerant circuit diagram showing a
modification of the second embodiment, and corresponds to FIG.
5;
[0028] FIG. 13 is a diagram showing an applied example to a
refrigerator, and corresponds to FIG. 6; and
[0029] FIG. 14 is a diagram showing an applied example to a
refrigerator, and corresponds to FIG. 7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] Preferred embodiments according to the present invention
will be described hereunder with reference to the accompanying
drawings.
[0031] FIG. 1 is a refrigerant circuit diagram showing a first
embodiment according to the present invention. A refrigerating
machine 30 is equipped with a compressor 1, a radiator 2, a first
expansion valve (pressure-reducing device) 3 and a gas-liquid
separator 4 which are connected to one another in this order. A
part of the refrigerant circuit which extends from the compressor 1
through the radiator 2 to the inlet port of the first expansion
valve 3 constitutes a high-pressure side circuit.
[0032] The compressor 1 is a two-stage compressor, and it includes
a first-stage compressing portion 1A, a second-stage compressing
portion 1B and an intermediate cooler 1C between the first-stage
and second-stage compressing portions 1A and 1B. Reference numeral
8 represents a check valve. The refrigerating machine 30 is further
equipped with a unit (gas refrigerant introduction
inhibiting/allowing unit) 5 which selectively introducing gas
refrigerant separated in the gas-liquid separator 4 into an
intermediate pressure portion of the compressor 1. In this
construction, the intermediate pressure portion is located between
the intermediate cooler 1C and the second-state compressing portion
1B. The compressor 1 of the present invention is not limited to the
two-stage compressor. If the compressor 1 is a one-stage
compressor, the gas refrigerant introduction inhibiting/allowing
unit 5 may be designed so as to return gas refrigerant to an
intermediate pressure portion of the one-stage compressor. In this
embodiment, the gas refrigerant introduction inhibiting/allowing
unit 5 is constructed by a gas pipe 6 and an opening/closing valve
91 provided in the gas pipe 6. Accordingly, the introduction of the
gas refrigerant into the intermediate pressure portion is started
(allowed) or stopped (inhibited) by opening/closing the
opening/closing valve 91.
[0033] Furthermore, the refrigerating machine 30 is provided with a
low-pressure side circuit 9 for circulating liquid refrigerant
separated in the gas-liquid separator 4, and the low-pressure side
circuit 9 is provided with a heat absorbing unit 10 which
selectively functions in different temperature zones. The heat
absorbing unit 10 is constructed by a second expansion valve 11 and
one heat absorber 14. By controlling the valve opening degree of
the second expansion valve 11, the evaporating pressure in the heat
absorber 14 is controlled. If the evaporating pressure is
increased, the evaporating temperature is increased, and thus a
refrigerating operation is carried out. On the other hand, if the
evaporating pressure is reduced, the evaporating temperature in the
heat absorber 14 is lowered, and thus a freezing operation is
carried out. The refrigerant passed through the heat absorber 14 is
passed through the check valve 8 and returned to the suction
portion of the compressor 1.
[0034] In this embodiment, the heat absorber 14 is provided with a
unit 23 for selectively guiding cold air passed through the heat
absorber 14 to plural chambers (refrigerating chamber 21, freezing
chamber 22) which are controlled to different temperature zones.
The unit 23 contains an air flowing duct 24 and a switching dumper
25, and a controller 26 for switching the operation to one of the
refrigerating and freezing operations is connected to the switching
dumper 25.
[0035] The controller 26 is also connected to the expansion valves
3 and 11 and the opening/closing valve 91. For example when the
load of the freezing chamber 22 is tilted, the switching dumper 25
is inclined to a position indicated in FIG. 1 to guide cold air to
the freezing chamber 22 (freezing operation). Under freezing
operation, the opening/closing valve 91 is opened, and the gas
refrigerant separated in the gas-liquid separator 4 is introduced
into the intermediate pressure portion of the compressor 1 as
indicated by a broken line. When the load of the refrigerating
chamber 21 is increased, the switching dumper 25 is tilted to the
opposite position to the position shown in FIG. 1 to guide cold air
to the refrigerating chamber 21 (refrigerating operation) Under the
refrigerating operation, the opening/closing valve 91 is closed,
and the introduction of the gas refrigerant into the intermediate
pressure portion of the compressor 1 is inhibited. The
opening/closing valve 91 constitutes the gas refrigerant
introduction inhibiting/allowing unit.
[0036] The refrigerant circuit is filled with such refrigerant that
the high-pressure side of the refrigerant circuit is set to
supercritical pressure under operation in accordance with a
condition, for example, when the outside temperature is increased
to 30.degree. C. or more in summer season, when the load is
increased or the like. Carbon dioxide refrigerant is filled as the
above refrigerant. In place of carbon dioxide refrigerant,
ethylene, diborane, ethane, nitrogen oxide or the like may be used
as the refrigerant in which the high-pressure side circuit is
operated under supercritical pressure.
[0037] In the above construction, even when the gas refrigerant
separated in the gas-liquid separator 4 is circulated in the
low-pressure side circuit 9, it cannot be used for cooling.
Accordingly, if the gas refrigerant is turned to the suction port
of the first-stage compressing portion 1A, it would reduce the
efficiency of the refrigerating cycle.
[0038] Therefore, the gas refrigerant is introduced into the
intermediate pressure portion of the compressor 1. In this
embodiment, under the control of the controller 26 described above,
introduction of the gas refrigerant into the intermediate pressure
portion of the compressor 1 is allowed under freezing operation in
which the temperature zone is low. On the other hand, introduction
of the gas refrigerant into the intermediate pressure portion is
inhibited under refrigerating operation in which the temperature
zone is high.
[0039] FIG. 2 is an enthalpy-pressure (ph) diagram showing a
two-stage compressor two-stage expansion cycle when gas refrigerant
is introduced into the first intermediate pressure portion X of the
compressor 1 under both the refrigerating operation and the
freezing operation.
[0040] In FIG. 2, a cycle indicated by a solid line is formed
during freezing operation (freezing around -26.degree. C.). (1)
represents the suction port of the first-stage compressor 1A, (2)
represents the discharge port of the first-compressing portion 1A,
(3) represents the suction port of the second-stage pressing
portion 1B, and (4) represents the discharge port of the
second-stage compressing portion 1A. The refrigerant discharged
from the compressor 1 is circulated through the radiator 2 and
cooled. (5) represents the inlet port of the first expansion valve
3, and (6) represents the outlet port of the first expansion valve
3. Under the state of (6), the refrigerant becomes two-phase
mixture of gas/liquid.
[0041] The ratio of gas and liquid corresponds to the ratio of the
length of the line segment of L1 (gas) and the length of the line
segment of L2 (liquid). The refrigerant enters the gas-liquid
separator 4 under the state that the refrigerant keeps the
two-phase mixture. The gas refrigerant separated in the gas-liquid
separator is introduced into the intermediate pressure portion of
the compressor 1, that is, between the intermediate cooler 1C and
the second-stage pressing portion 1B. (21) represents the outlet
port of the gas-liquid separator 4. The refrigerant passed through
the outlet port of the gas-liquid separator 4 reaches the suction
port of the second-stage compressing portion 1B of (3), and then is
compressed in the second-stage compressing portion 1B. The liquid
refrigerant separated in the gas-liquid separator 4 is circulated
in the low-pressure side circuit 9. (7) represents the outlet port
of the gas-liquid separator 4, that is, the inlet port of the
second expansion valve 11, (8) represents the outlet port of the
second expansion valve 11 and (22) represents the outlet port of
the heat absorber 14. The liquid refrigerant entering the heat
absorber 14 evaporates to absorb heat. (1) represents the suction
port of the first-stage compressing portion 1A.
[0042] On the other hand, a cycle indicated by a broken line is
formed during refrigerating operation (refrigeration around
-5.degree. C.). That is, the state of the cycle is varied in the
following order: (9) the suction port of the first-stage
compressing portion 1A, (10) the discharge port of the first-stage
compressing portion 1A, (11) the suction port of the second-stage
compressing portion 1B, (12) the discharge port of the second-stage
compressing portion 1B, (5) the inlet port of the first expansion
valve 3, (13) the outlet port of the first expansion valve 3, (14)
the outlet port of the gas-liquid separator 4 and thus the inlet
port of the second expansion valve 11, (15) the outlet port of the
second expansion valve 11 and (9) the suction port of the
first-stage compressor 1A.
[0043] Referring to FIG. 2, the pressure (13) of the outlet port of
the first expansion valve 3 in the broken-line cycle (under
refrigerating operation) is remarkably higher than the pressure (6)
of the outlet port of the first expansion valve 3 under the
solid-line cycle (under freezing operation). When the pressure of
the outlet port of the first expansion valve 3 is increased, the
amount of the gas component in the refrigerant before the
refrigerant enters the gas-liquid separator 4 is reduced. This is
because the ratio between gas and liquid at the inlet port of the
gas-liquid separator 4 corresponds to the ratio of L1 (gas) and L2
(liquid) or the ratio of L3 (gas) and L4 (liquid) as described
above. In conformity with this, a large amount of gas refrigerant
is introduced into the intermediate pressure portion of the
compressor 1 under the solid-line cycle (freezing operation),
however, the amount of gas refrigerant to be introduced into the
intermediate pressure portion is very small under the broken-line
cycle (refrigerating operation).
[0044] That is, under freezing operation, the amount of the gas
refrigerant introduced into the intermediate pressure portion of
the compressor 1 is increased, and the efficiency of the
refrigerating cycle can be enhanced by some degree because the gas
component which does not contribute to cooling is not circulated in
the low pressure circuit 9.
[0045] Particularly in the above construction, since carbon oxide
refrigerant is filled in the refrigerant circuit, the amount of the
gas component is larger as compared with chlorofluorocarbon (Freon)
type refrigerant. Accordingly, a higher efficiency can be achieved
by introducing a larger amount of gas component into the
intermediate pressure portion of the compressor 1. On the other
hand, under refrigerating operation in which the temperature zone
is high, the occurrence amount of gas refrigerant to be introduced
into the intermediate pressure portion of the compressor 1 itself
is small, and thus even when the gas refrigerant is introduced into
the intermediate pressure portion, the efficiency of the
refrigerating cycle cannot be so enhanced as compared with
complication in pipe construction, etc.
[0046] According to this embodiment, introduction of gas
refrigerant into the intermediate pressure portion of the
compressor 1 is allowed only under freezing operation because of
the effect of introducing the gas refrigerant is higher. On the
other hand, under refrigerating operation in which the temperature
zone is high, introduction of gas refrigerant into the intermediate
pressure portion of the compressor 1 is inhibited. Therefore, the
variable cycle can be implemented and the efficiency of the
refrigerating cycle is enhanced by a simple pipe construction and
simple control.
[0047] Furthermore, according to this embodiment, all the parts of
the heat absorbing unit 10 which selectively function in different
temperature zones, that is, the second expansion valve 11 and the
heat absorber 14 are provided to the low pressure side circuit 9.
Therefore, for example when the refrigerating operation is carried
out and when the freezing operation is carried out, the remarkably
highly efficient operation can be performed without reducing the
efficiency.
[0048] FIG. 3 shows an applied example of the refrigerating machine
of the above embodiment to a refrigerator.
[0049] A refrigerator (fridge) 40 has a refrigerating chamber 41 at
the upper stage and a freezing chamber 42 at the lower stage. An
inner partition wall 43 is provided at the inner back side of the
freezing chamber 42, and the heat absorber 14 described above is
provided in an air flow path 44 partitioned by the inner partition
wall 43. A first switching dumper 45 is disposed at the inlet port
A of the air flow path 44, and the first switching dumper 45 is
switched between a closing position (broken-line position) for
closing the inlet port A of the air flow path 44 and an opening
position (solid-line position) for opening the inlet port A of the
air flow path 44. A back side air flow path 46 is formed on the
back wall 47 of the refrigerator 40. When the first switching
dumper 45 is switched to the broken-line position, the inlet port 4
of the air flow path 44 and the refrigerating chamber 41
intercommunicate with each other through the back side air flow
path 46. Furthermore, a fan 48 and a second switching dumper 49 are
disposed at the outlet port B of the air flow path 44, and the
second switching dumper 49 is switched between a closing position
(broken-line position) for closing the outlet port B of the air
flow path 44 and an opening position (solid-line position) for
opening the outlet port B of the air flow path 44. At the
solid-line position, the second switching dumper 49 closes an
opening 51 formed in an intermediate partition wall 50.
[0050] In the above construction, during freezing operation, the
compressor 1 is turned on, the fan 48 is turned on, the
opening/closing valve 91 is opened, and each of the dumpers 45 and
49 is switched to the solid-line position. Accordingly, air in the
freezing chamber 42 is circulated in the heat absorber 14, and
supplied to the freezing chamber 42. During refrigerating
operation, the opening/closing valve 91 is closed, and each of the
dumpers 45 and 49 is switched to the broken-line position.
Accordingly, air in the refrigerating chamber 41 enters the air
flow path 44 through the back side air flow path 46, and it is
circulated in the heat absorber 14 and then supplied to the
refrigerating chamber 41.
[0051] FIG. 5 shows a refrigerant circuit of a modification of the
first embodiment.
[0052] The construction of this modification is different from the
construction shown in FIG. 1 in the construction of the heat
absorbing unit 10. The heat absorbing unit 10 of this modification
comprises a three-way valve 11, a first capillary tube 12, a heat
absorber 57 for refrigeration which is connected to the first
capillary tube 12 in series, a second capillary tube 13 which is
connected to the first capillary tube 12 and the heat absorber 57,
and a heat absorber 58 for freezing which is connected to the
second capillary tube 13 in series. Reference numeral 59 represents
a check valve. When the refrigerant is made to flow into the first
capillary tube 12 by switching the three-way valve 11, the flow
amount of the refrigerant flowing in the heat absorber 57 is
increased, and the refrigerating operation is carried out.
Furthermore, when the refrigerant is made to flow into the second
capillary tube 13 by switching the three-way valve 11, the flow
amount of the refrigerant flowing in the heat absorber 58 is
increased (the flow amount of the refrigerant flowing in the heat
absorber 57 is reduced), and thus the freezing operation is carried
out.
[0053] FIG. 6 shows an applied example of the modification to a
refrigerator (fridge).
[0054] The refrigerator 40 has a refrigerating chamber 41 at the
upper stage, and a freezing chamber at the lower stage. Inner
partition walls 61 and 62 are provided at the inner back sides of
the respective chambers 41 and 42. The heat absorber 57, 58 and the
fan 63, 64 are disposed in an air flow path 44 partitioned by the
inner partition wall 61, 62. In this construction, the three-way
valve 11 is switched in accordance with thermo-on, thermo-off of
the refrigerating operation and the freezing operation to make the
refrigerant flow into any one of the heat absorbers 57 and 58, and
the corresponding one of the fans 62 and 63 is driven.
[0055] FIG. 7 shows another modification of the first
embodiment.
[0056] This construction of this modification is different from the
construction of FIG. 6 in the construction of the heat absorbing
unit 10. In the heat absorbing unit 10 of this modification, the
three-way valve is omitted, and electrical motor operated valves 65
and 66 are connected to the capillary tubes 12 and 13 in series,
respectively. In this construction, the electrical motor operated
valves 65 and 66 are turned on or off in accordance with thermo-on,
thermo-off of the refrigerating operation and the freezing
operation to make the refrigerant selectively flow into any one of
the heat absorbers 57 and 58, and the corresponding one of the fans
62 and 63 is driven. In these embodiments, substantially the same
effects can be achieved.
[0057] The present invention is not limited to the above
embodiments, and various modifications may be made without
departing from the subject matter of the present invention. In the
above embodiments, the gas refrigerant introduction
inhibiting/allowing unit is constructed by the opening/closing
valve 91, however, the present invention is not limited to the
opening/closing valve 91. For example, a circuit construction
achieved by combining a check valve, etc. may be used insofar as it
introduces the gas component of the refrigerant into the
intermediate pressure portion of the compressor 1 under freezing
operation while the introduction of the gas component is inhibited
under refrigerating operation.
[0058] Furthermore, in the above embodiments, carbon dioxide
refrigerant is enclosed in the refrigerant circuit. However, the
present invention is not limited to carbon dioxide refrigerant, and
it is needless to say that chlorofluorocarbon (freon) type
refrigerant or the like may be enclosed in the refrigerant circuit
in place of carbon dioxide refrigerant. Furthermore, the specific
construction of the gas refrigerant introducing unit 5 and the
place from which the gas component is introduced are not limited to
specific ones, and they may be arbitrarily determined insofar as it
can introduced the gas component of the refrigerant into the
intermediate pressure portion of the compressor 1 in accordance
with the operation condition.
[0059] In the above embodiments, the introduction of the gas
refrigerant into the intermediate pressure portion is inhibited on
the assumption that the occurrence amount (L3) of the gas
refrigerant introduced into the intermediate portion of the
compressor 1 is small during refrigerating operation in which the
temperature zone is high. However, when the occurrence amount (L3)
of the gas refrigerant is not small to the extent that it cannot be
neglected, the refrigeration efficiency can be further enhanced by
designing the refrigerating machine so that the gas refrigerant
which does not contribute to cooling is prevented from being
circulated in the low-pressure circuit side.
[0060] Next, an embodiment in which the gas refrigerant is
introduced into the compressor 1 under refrigerating operation to
further enhance the efficiency of the refrigerating cycle.
[0061] FIG. 8 is a refrigerant circuit diagram showing a second
embodiment of the present invention. A refrigerating machine 130 of
this embodiment has the same refrigerant circuit as the first
embodiment except for apart of the construction. In the following
description, the different construction from the first embodiment
will be mainly described. The same or corresponding constituent
elements are represented by the same references, and the detailed
description thereof is omitted.
[0062] The refrigerating machine 130 is equipped with a refrigerant
gas introducing unit 105 for selectively introducing gas
refrigerant separated in the gas-liquid separator 4 into one of a
first intermediate pressure portion X of the compressor 1 and a
second intermediate pressure portion Y which is nearer to the low
pressure suction side than the first intermediate pressure portion
X. In this construction, the first intermediate pressure portion X
is located between the intermediate cooler 1C and the second-stage
compressing portion 1B, and the second intermediate pressure
portion Y is located at some midpoint of the first-stage
compressing portion 1A. In this embodiment, the compressor 1
comprises a two-stage compressor, however, the compressor 1 is not
limited to the two-stage compressor.
[0063] The gas refrigerant introducing unit 105 comprises a gas
pipe 6, a three-way valve 81 provided in the gas pipe 6 and two
branch gas pipes 82 and 83 branched from the three-way valve 81.
One branch gas pipe 82 is connected to the first intermediate
pressure portion X, and the other branch gas pipe 83 is connected
to the second intermediate pressure portion Y. Here, the three-way
valve 81 and the branch gas pipe 83 constitutes the gas refrigerant
introducing unit. Accordingly, when the gas pipe 6 and the branch
gas pipe 82 intercommunicate with each other by switching the
three-way valve 81, the gas refrigerant is introduced into the
first intermediate pressure portion X as indicated by an
broken-line arrow. When the gas pipe 6 and the branch gas pipe 83
intercommunicate with each other by switching the three-way valve
81, the gas refrigerant is introduced into the second intermediate
pressure portion Y. Here, the three-way valve 81 is not limited to
an electromagnetic type, and a differential pressure driving type
or the like. Furthermore, the first intermediate pressure portion X
corresponds to the intermediate pressure portion in the first
embodiment.
[0064] The controller 26 is connected to the compressor 1, the
expansion valves 3 and 11 and the three-way valve 81. For example,
when the load of the freezing chamber 22 is increased, the valve
opening degree of the second expansion valve 11 is increased, the
flow amount flowing in the heat absorber 14 is increased, and the
switching dumper 25 is tilted to the position shown in FIG. 8 to
thereby guide cold air to the freezing chamber 22 (freezing
operation). During freezing operation, the three-way valve 81 is
switched to make the gas pipe 6 and the branch gas pipe 82
intercommunicate with each other, so that the gas refrigerant
separated in the gas-liquid separator 4 is introduced into the
first intermediate pressure portion X as indicated by the
broken-line arrow. Furthermore, when the load of the refrigerating
chamber 21 is increased, the switching dumper 25 is tilted to the
opposite position to the position shown in FIG. 8 to guide cold air
to the refrigerating chamber 21 (refrigerating operation). During
refrigerating operation, the three-way valve 81 is switched to make
the gas pipe 6 and the branch gas pipe 83 intercommunicate with
each other, and the gas refrigerant is introduced into the second
intermediate pressure portion Y.
[0065] As in the case of the first embodiment, the refrigerant
circuit is filled with such refrigerant that the high-pressure side
of the refrigerant circuit is set to supercritical pressure under
operation in accordance with a condition, for example, when the
outside temperature is increased to 30.degree. C. or more in summer
season, when the load is increased or the like. Carbon dioxide
refrigerant is filled as the above refrigerant. In place of carbon
dioxide refrigerant, ethylene, diborane, ethane, nitrogen oxide or
the like may be used as the refrigerant in which the high-pressure
side circuit is operated under supercritical pressure.
[0066] In the above construction, even when the gas refrigerant
separated in the gas-liquid separator 4 is circulated in the low
pressure side circuit 9, it is not usable for cooling. Therefore,
if the gas refrigerant concerned is returned to the suction port of
the first-stage compressing portion 1A, the efficiency of the
refrigerating cycle would be reduced. Therefore, the gas
refrigerant is introduced into the intermediate pressure portion of
the compressor 1. However, as described with reference to the first
embodiment, when the occurrence amount (L3) of the gas refrigerant
is small, even if the gas refrigerant is circulated in the low
pressure side circuit 9, it hardly affects the efficiency of the
refrigerating cycle. In other words, even when such a small amount
of gas refrigerant is introduced into the intermediate pressure
portion of the compressor, it does not enhance the efficiency of
the refrigerating cycle. Accordingly, in this embodiment, under the
control of the controller 26 described above, the gas refrigerant
is introduced into the first intermediate pressure portion X of the
compressor 1 under freezing operation in which the temperature zone
is low, and the gas refrigerant is introduced into the second
intermediate pressure portion Y nearer to the low-pressure suction
side of the compressor 1 than the first intermediate pressure
portion X under refrigerating operation in which the temperature
zone is high, whereby the efficiency of the refrigerating cycle is
further enhanced.
[0067] FIG. 9 is an enthalpy-pressure (ph) diagram showing the
two-stage compression two-stage expansion cycle when the gas
refrigerant is introduced into the first intermediate pressure
portion X of the compressor 1 under freezing operation in which the
temperature zone is low while the gas refrigerant is introduced
into the second intermediate pressure portion Y of the compressor 1
under refrigerating operation in which the temperature zone is
high. Here, the ph diagram of FIG. 9 is compared with the ph
diagram of FIG. 2 when the gas refrigerant is introduced into the
first intermediate pressure portion X of the compressor 1 in both
the refrigerating and freezing operations.
[0068] In FIGS. 2 and 9, the refrigerating cycle indicated by a
solid line is formed during freezing operation (freezing around
-26.degree. C.). (1) represents the suction port of the first-stage
compressing portion 1A, (2) represents the discharge port of the
first-stage compressing portion 1A, (3) represents the suction port
of the second-stage compressing portion 1B, and (4) represents the
discharge port of the second-stage pressing portion 1B. The
refrigerant discharged from the compressor 1 is circulated through
the radiator 2 to be cooled. (5) represents the inlet port of the
first expansion valve, and (6) represents the outlet port of the
first expansion valve 3. Under this state, the refrigerant becomes
two-phase mixture of gas and liquid.
[0069] The ratio of gas and liquid corresponds to the ratio of the
length of the line segment of L1 (gas) and the length of the line
segment of L2 (liquid). The refrigerant enters the gas-liquid
separator 4 under the state that the refrigerant is the two-phase
mixture. The gas refrigerant separated in the gas-liquid separator
4 is introduced into the intermediate portion of the compressor 1,
that is, between the intermediate cooler 1C and the second-stage
compressing portion 1B. (21) represents the outlet port of the
gas-liquid separator 4. The refrigerant passed through the
gas-liquid separator 4 reaches the first intermediate pressure
portion X, that is, the suction port of the second-stage
compressing portion 1B of (3), and compressed in the second-stage
compressing portion 1B. On the other hand, the liquid refrigerant
separated in the gas-liquid separator 4 is circulated in the low
pressure side circuit 9. (7) represents the outlet port of the
gas-liquid separator 4, and thus the inlet port of the second
expansion valve, (8) represents the outlet port of the second
expansion valve 11, and (22) represents the outlet port of the heat
absorber 14. The liquid refrigerant entering the heat absorber 14
evaporates and absorbs heat. (1) represents the suction port of the
first-stage compressing portion 1A.
[0070] On the other hand, the cycle indicated by a broken line is
formed under refrigerating operation (refrigeration around
-5.degree. C.). That is, in FIG. 9, the state is varied in the
following order: (9) the suction port of the first-stage
compressing portion 1A, (11) the second intermediate pressure
portion Y, that is, the intermediate portion of the first-stage
pressure compressing portion 1A, (12) the discharge port of the
first-stage compressing portion 1A and thus the inlet port of the
intermediate cooler 1C, (13) the outlet port of the intermediate
cooler 1C and thus the suction port of the second-stage compressing
portion 1B, (14) the discharge port of the second-stage compressing
portion 1B, (5) the inlet port of the first expansion valve 3, (15)
the outlet port of the first expansion valve, (16) the outlet port
of the gas-liquid separator 4 and thus the inlet port of the second
expansion valve 11, (17) the outlet port of the second expansion
valve 11, and (9) the suction port of the first-stage compressing
portion 1A.
[0071] In FIG. 2, the gas refrigerant is introduced into the first
intermediate pressure portion X of the compressor 1, and thus the
state is varied in the following order: (9) the suction port of the
first-stage compressing portion 1A, (10) the discharge port of the
first-stage compressing portion 1A, (11) the first intermediate
pressure portion X, that is, the outlet port of the intermediate
cooler 1C, and thus the suction port of the second-stage
compressing portion 1B, (12) the discharge port of the second-stage
compressing portion 1B, (5) the inlet port of the first expansion
valve 3, (13) the outlet port of the first expansion valve 3, (14)
the outlet port of the gas-liquid separator 4, that is, the inlet
port of the second expansion valve 11, (15) the outlet port of the
second expansion valve 11 and the suction port of the first-stage
compressing portion 1A.
[0072] When comparing the cases of FIGS. 2 and 9, the gas
refrigerant is introduced into the first intermediate pressure
portion X of the compressor 1 under freezing operation in which the
temperature zone is low in both the cases. Accordingly, under
freezing operation, substantially the same cycle indicated by the
solid line is formed in FIGS. 2 and 9.
[0073] On the other hand, under the refrigerating operation in
which the temperature zone is high, the gas refrigerant is
introduced into the second intermediate pressure portion Y nearer
to the low voltage suction side than the first intermediate
pressure portion X in FIG. 9 whereas the gas refrigerant is
introduced into the first intermediate pressure portion X of the
compressor 1 in FIG. 2. The pressure of the second intermediate
pressure portion Y is lower than the pressure of the first
intermediate pressure portion X. Accordingly, when the gas
refrigerant is introduced into the second intermediate pressure
portion Y having the lower pressure, the pressure at the outlet
port of the first expansion valve 3 can be reduced as compared with
the case where the gas refrigerant is introduced into the first
intermediate pressure portion X.
[0074] That is, under refrigerating operation, the pressure of the
line segments L5 and L6 (FIG. 9) is lower than the pressure of the
line segments L3 and L4 (FIG. 2) in the cycle indicated by the
broken line. When the pressure at the outlet port of the first
expansion valve 3 is reduced, the amount of the gas component of
the refrigerant before it enters the gas-liquid separator 4 is
increased. This is also apparent from the fact that the line
segment L5 is longer than the line segment L3. As described above,
the ratio of gas and liquid at the inlet port of the gas-liquid
separator 4 corresponds to the ratio of L5 (gas) and L6 (liquid) in
FIG. 9, and also corresponds to the ratio of L3 (gas) and L4
(liquid) in FIG. 2. Accordingly, the amount of the gas refrigerant
introduced into the intermediate pressure portion of the compressor
1 is larger as compared with FIG. 2, and thus it cannot be
neglected. Therefore, the efficiency of the refrigerating cycle can
be enhanced by the degree corresponding to the effect achieved when
the gas component which does not contribute to cooling is prevented
from being circulated in the low pressure circuit 9. Particularly,
in the above construction, carbon dioxide refrigerant is enclosed
in the refrigerant circuit, and thus the amount of the gas
component of the refrigerant is larger in the ratio of gas and
liquid separated in the gas-liquid separator 4 as compared with
chlorofluorocarbon (Freon) type refrigerant, and a larger amount of
gas component is introduced to the intermediate pressure portion o
the compressor 1, whereby the efficiency of the refrigerating cycle
can be more enhanced.
[0075] In this embodiment, all the elements of the heat absorbing
unit 10 which selectively functions in different temperature zones,
that is, the second expansion valve 11 and the heat absorber 14 are
provided to the low pressure side circuit 9. Therefore, in both the
case where the refrigerating operation is carried out and the case
where the freezing operation is carried out, the highly efficient
operation can be performed without reducing the efficiency.
[0076] The refrigerating machine may be designed so that the gas
refrigerant introduction inhibiting/allowing unit 5 according to
the first embodiment and the gas refrigerant introducing unit 105
according to the second embodiment is connected to each other in
series. In this case, both the units are switched to each other in
accordance with the reduction of the efficiency of the
refrigerating cycle which is caused by the occurrence amount of the
gas refrigerant under refrigerating operation. Specifically, the
gas refrigerant introduction inhibiting/allowing unit 5 is secured
to the gas refrigerant discharge side of the gas-liquid separator
4, and the gas refrigerant introducing unit 105 is secured to the
output side of the gas refrigerant introduction inhibiting/allowing
unit 5.
[0077] The gas refrigerant introducing unit 105 may be designed so
as to introduce the refrigerant into the first intermediate
pressure portion of the compressor 1 or the second intermediate
pressure portion nearer to the suction side of the compressor 1
than the first intermediate pressure portion in accordance with the
operating condition, and the specific construction thereof and the
introducing position thereof are determined freely.
[0078] FIGS. 10 to 14 show examples when the above embodiment is
applied to a refrigerator, and correspond to FIGS. 3 to 7 when the
gas refrigerant introduction inhibiting/allowing unit 5 is changed
to the gas. refrigerant introducing unit 105. Each operation in the
refrigerator is identical to the corresponding operation described
with reference to FIGS. 3 to 7, and the duplicative description
thereof is omitted.
[0079] As described above, according to the present invention,
under freezing operation having a higher effect, the gas
refrigerant is introduced into the intermediate pressure portion
(first intermediate pressure portion) of the compressor 1, and
under refrigerating operation in which the temperature zone is
high, the gas refrigerant is introduced into the intermediate
pressure portion (second intermediate pressure portion) at the
lower pressure side than the first intermediate pressure portion.
Therefore, the variable cycle can be implemented and the efficiency
of the refrigerating cycle can be enhanced by a simple pipe
construction and a simple control operation.
[0080] The gas refrigerant introducing inhibiting/allowing unit of
the first embodiment and the gas refrigerant introducing unit of
the second embodiment may be used independently of each other,
however, a combination thereof may be arranged a gas refrigerant
introduction inhibiting/allowing switching unit having both the
functions thereof in the gas pipe 6 between the gas-liquid
separator 4 and the compressor 1. In this case, the gas refrigerant
introduction inhibiting/allowing unit 5 is provided at the
gas-liquid separator 4 side while the gas refrigerant introducing
unit 105 is disposed between the gas refrigerant introduction
inhibiting/allowing unit 5 and the compressor 1. Furthermore, under
freezing operation, the gas refrigerant introduction
inhibiting/allowing unit and the gas refrigerant introducing unit
are operated so that the gas refrigerant from the gas-liquid
separator 4 is passed through the gas refrigerant introduction
inhibiting/allowing unit, and further passed through the gas
refrigerant introducing unit to the first intermediate pressure
portion X of the compressor 1. On the other hand, under
refrigerating operation, the gas refrigerant introduction
inhibiting/allowing unit and the gas refrigerant introducing unit
are selectively operated so that the gas refrigerant from the
gas-liquid separator 4 is inhibited from being introduced to the
compressor by the gas refrigerant introduction inhibiting/allowing
unit or allowed to be introduced to the compressor through the gas
refrigerant introduction inhibiting/allowing unit, passed through
the gas refrigerant introducing unit and then introduced to the
second intermediate pressure portion Y of the compressor in
accordance with the condition such as the gas refrigerant amount at
the outlet port of the first expansion valve 3 or the like.
[0081] The present invention is not limited to the above
embodiments, and various modifications may be made without
departing from the subject matter of the present invention. For
example, in the above construction, carbon dioxide refrigerant is
enclosed in the refrigerant circuit, however, the present invention
is not limited to carbon dioxide refrigerant. For example,
chlorofluorocarbon (Freon) type refrigerant or the like may be
enclosed in the refrigerant circuit in place of carbon dioxide
refrigerant.
* * * * *