U.S. patent application number 11/609617 was filed with the patent office on 2007-06-14 for vapor compression refrigerating systems.
This patent application is currently assigned to SANDEN CORPORATION. Invention is credited to Yuuichi Matsumoto, Kenichi Suzuki, Masato Tsuboi.
Application Number | 20070130988 11/609617 |
Document ID | / |
Family ID | 37876936 |
Filed Date | 2007-06-14 |
United States Patent
Application |
20070130988 |
Kind Code |
A1 |
Matsumoto; Yuuichi ; et
al. |
June 14, 2007 |
VAPOR COMPRESSION REFRIGERATING SYSTEMS
Abstract
A vapor compression refrigerating system includes a compressor,
a radiator connected to the compressor via a first tube, a first
pressure reducing mechanism connected to the radiator via a second
tube, and a separator connected to the first pressure reducing
mechanism via a third tube and the compressor via a fourth tube.
The separator includes an oil separator which is configured to
separate an oil from the refrigerant, and a liquid and gas
separator formed integral with the oil separator. The liquid and
gas separator is configured to separate a liquid portion and a gas
portion from the refrigerant, and the separator is further
configured to transmit the oil and the gas portion to the
compressor via the fourth tube. The system also includes a second
pressure reducing mechanism connected to the separator via a fifth
tube, and an evaporator connected to the second pressure reducing
mechanism via a sixth tube and operationally coupled to the
compressor via a seventh tube. The second pressure reducing
mechanism is configured to receive the liquid portion from the
separator.
Inventors: |
Matsumoto; Yuuichi;
(Isesaki-shi, Gunma, JP) ; Tsuboi; Masato;
(Isesaki-shi, Gunma, JP) ; Suzuki; Kenichi;
(Isesaki-shi, Gunma, JP) |
Correspondence
Address: |
BAKER BOTTS LLP;C/O INTELLECTUAL PROPERTY DEPARTMENT
THE WARNER, SUITE 1300
1299 PENNSYLVANIA AVE, NW
WASHINGTON
DC
20004-2400
US
|
Assignee: |
SANDEN CORPORATION
20 Kotobuki-cho
Isesaki-shi
JP
372-8502
|
Family ID: |
37876936 |
Appl. No.: |
11/609617 |
Filed: |
December 12, 2006 |
Current U.S.
Class: |
62/512 ; 62/471;
62/513 |
Current CPC
Class: |
F25B 2400/053 20130101;
F25B 9/008 20130101; F25B 41/39 20210101; F25B 40/00 20130101; F25B
2309/061 20130101; F25B 2400/13 20130101; F25B 2400/23
20130101 |
Class at
Publication: |
062/512 ;
062/513; 062/471 |
International
Class: |
F25B 43/02 20060101
F25B043/02; F25B 43/00 20060101 F25B043/00; F25B 41/00 20060101
F25B041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 12, 2005 |
JP |
2005-357701 |
Claims
1. A vapor compression refrigerating system comprising: a
compressor configured to compress a refrigerant; a radiator
connected to the compressor via a first tube, wherein the radiator
is configured to receive the refrigerant from the compressor and to
radiate the refrigerant; a first pressure reducing mechanism
connected to the radiator via a second tube, wherein the first
pressure reducing mechanism is configured to receive the
refrigerant from the radiator and to reduce a pressure of the
refrigerant; a separator connected to the first pressure reducing
mechanism via a third tube and the compressor via a fourth tube,
wherein the separator is configured to receive the refrigerant from
the first pressure reducing mechanism, and the separator comprises:
an oil separator which is configured to separate an oil from the
refrigerant; and a liquid and gas separator formed integral with
the oil separator, wherein the liquid and gas separator is
configured to separate a liquid portion and a gas portion from the
refrigerant, and the separator is further configured to transmit
the oil and the gas portion to the compressor via the fourth tube;
a second pressure reducing mechanism connected to the separator via
a fifth tube, wherein the second pressure reducing mechanism is
configured to receive the liquid portion from the separator and to
reduce a pressure of the liquid portion; and an evaporator
connected to the second pressure reducing mechanism via a sixth
tube and operationally coupled to the compressor via at least a
seventh tube, wherein the evaporator is configured to receive the
liquid portion from the second pressure reducing mechanism and to
evaporate the liquid portion.
2. The vapor compression refrigerating system of claim 1, wherein
the evaporator is connected to the compressor via the separator,
and the evaporator is configured to receive the liquid portion from
the second pressure reducing mechanism and to evaporate the liquid
portion into an evaporated portion and to transmit the evaporated
portion to the separator, wherein the system further comprises
means for exchanging heat between the liquid portion and evaporated
portion.
3. The vapor compression refrigerating system of claim 1, wherein
the oil separator comprises at least one of a centrifugal oil
separator and a collision oil separator.
4. The vapor compression refrigerating system of claim 1, wherein
the first pressure reducing mechanism is configured to control a
pressure of the refrigerant at an exit side of the first pressure
reducing mechanism to be less than or equal to a critical
pressure.
5. The vapor compression refrigerating system of claim 1, wherein
at least one of the first pressure reducing mechanism and the
second pressure reducing mechanism comprises a mechanical expansion
valve which changes a degree of expansion in response to at least
one of a temperature and a pressure of the refrigerant.
6. The vapor compression refrigerating system of claim 1, wherein
at least one of the first pressure reducing mechanism and the
second pressure reducing mechanism comprises an electronic
expansion valve which changes an opening degree of a valve by an
electric signal in response to at least one of a temperature and a
pressure of the refrigerant.
7. The vapor compression refrigerating system of claim 1, wherein
the refrigerant comprises carbon dioxide.
8. An air conditioning system comprising a vapor compression
refrigerating system, wherein the vapor compression refrigerating
system comprises: a compressor configured to compress a
refrigerant; a radiator connected to the compressor via a first
tube, wherein the radiator is configured to receive the refrigerant
from the compressor and to radiate the refrigerant; a first
pressure reducing mechanism connected to the radiator via a second
tube, wherein the first pressure reducing mechanism is configured
to receive the refrigerant from the radiator and to reduce a
pressure of the refrigerant; a separator connected to the first
pressure reducing mechanism via a third tube and the compressor via
a fourth tube, wherein the separator is configured to receive the
refrigerant from the first pressure reducing mechanism, and the
separator comprises: an oil separator which is configured to
separate an oil from the refrigerant; and a liquid and gas
separator formed integral with the oil separator, wherein the
liquid and gas separator is configured to separate a liquid portion
and a gas portion from the refrigerant, and the separator is
further configured to transmit the oil and the gas portion to the
compressor via the fourth tube; a second pressure reducing
mechanism connected to the separator via a fifth tube, wherein the
second pressure reducing mechanism is configured to receive the
liquid portion from the separator and to reduce a pressure of the
liquid portion; and an evaporator connected to the second pressure
reducing mechanism via a sixth tube and operationally coupled to
the compressor via at least a seventh tube, wherein the evaporator
is configured to receive the liquid portion from the second
pressure reducing mechanism and to evaporate the liquid
portion.
9. A vehicle comprising an air conditioning system, wherein the air
conditioning system comprises a vapor compression refrigerating
system, and the vapor compression refrigerating system comprises: a
compressor configured to compress a refrigerant; a radiator
connected to the compressor via a first tube, wherein the radiator
is configured to receive the refrigerant from the compressor and to
radiate the refrigerant; a first pressure reducing mechanism
connected to the radiator via a second tube, wherein the first
pressure reducing mechanism is configured to receive the
refrigerant from the radiator and to reduce a pressure of the
refrigerant; a separator connected to the first pressure reducing
mechanism via a third tube and the compressor via a fourth tube,
wherein the separator is configured to receive the refrigerant from
the first pressure reducing mechanism, and the separator comprises:
an oil separator which is configured to separate an oil from the
refrigerant; and a liquid and gas separator formed integral with
the oil separator, wherein the liquid and gas separator is
configured to separate a liquid portion and a gas portion from the
refrigerant, and the separator is lurer configured to transmit the
oil and the gas portion to the compressor via the fourth tube; a
second pressure reducing mechanism connected to the separator via a
fifth tube, wherein the second pressure reducing mechanism is
configured to receive the liquid portion from the separator and to
reduce a pressure of the liquid portion; and an evaporator
connected to the second pressure reducing mechanism via a sixth
tube and operationally coupled to the compressor via at least a
seventh tube, wherein the evaporator is configured to receive the
liquid portion from the second pressure reducing mechanism and to
evaporate the liquid portion.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to vapor compression
refrigerating systems. In particular, the present invention relates
to vapor compression refrigerating systems in which a separator
includes an oil separator integrated with a gas and liquid
separator to form a single separator, and a gas portion of a
refrigerant and an oil separated from the refrigerant flows from
the separator to a compressor via the same tube, such that the size
and the weight of the vapor compression refrigerating systems is
reduced.
[0003] 2. Description of Related Art
[0004] Freon group refrigerants have been used in known air
conditioning systems, Nevertheless, the use such Freon group
refrigerants has begun to be restricted due to environmental
concerns. In Europe, it has been proposed that carbon dioxide be
used as a refrigerant in place of Freon. Carbon dioxide refrigerant
is poison less and incombustible, however, the theoretical energy
efficiency of carbon dioxide as a refrigerant is relatively low,
there are problems associated with improving the efficiency of
carbon dioxide as a refrigerant. Moreover, when carbon dioxide is
used as a refrigerant, because a high-pressure side may reach a
super critical condition which exceeds a critical pressure, it is
necessary to use materials that may bear this pressure.
Consequently, the thickness of the materials increases, which
increases the weight of the air conditioner system.
[0005] One known method of improving the efficiency of carbon
dioxide as a refrigerant, which is described in Japanese Patent
Publication No. JP-A-2000-274890, is to use an oil separator to
prevent the circulation of oil to components other than the
compressor. Nevertheless, the oil separator increases the size of
the air conditioner. Moreover, if oil flows into the evaporator,
its heat transfer coefficient and its coefficient of heat exchange
are reduced.
SUMMARY OF THE INVENTION
[0006] Therefore, a need has arisen for vapor compression
refrigerating systems which overcome these and other shortcomings
of the related art. A technical advantage of the present invention
is that a separator may comprise an oil separator integrated with a
gas and liquid separator to form a single separator, and a gas
portion of the refrigerant and an oil separated from the
refrigerant may flow from the separator to a compressor via the
same tube, such that the size and the weight of the vapor
compression refrigerating system may be reduced relative to the
known vapor compression refrigerating systems.
[0007] According to an embodiment of the present invention, a vapor
compression refrigerating system comprises a compressor configured
to compress a refrigerant, and a radiator connected to the
compressor via a first tube. The radiator is configured to receive
the refrigerant from the compressor and to radiate the refrigerant.
The system also comprises a first pressure reducing mechanism
connected to the radiator via a second tube, and the first pressure
reducing mechanism is configured to receive the refrigerant from
the radiator and to reduce a pressure of the refrigerant. Moreover,
the system comprises a separator connected to the first pressure
reducing mechanism via a third tube and the compressor via a fourth
tube, and the separator is configured to receive the refrigerant
from the first pressure reducing mechanism. The separator comprises
an oil separator which is configured to separate an oil from the
refrigerant, and a liquid and gas separator formed integral with
the oil separator. The liquid and gas separator is configured to
separate a liquid portion and a gas portion from the refrigerant,
and the separator is further configured to transmit the oil and the
gas portion to the compressor via the fourth tube. The system also
comprises a second pressure reducing mechanism connected to the
separator via a fifth tube, and the second pressure reducing
mechanism is configured to receive the liquid portion from the
separator and to reduce a pressure of the liquid portion. Moreover,
the system comprises an evaporator connected to the second pressure
reducing mechanism via a sixth tube and operationally coupled to
the compressor via at least a seventh tube. The evaporator is
configured to receive the liquid portion from the second pressure
reducing mechanism and to evaporate the liquid portion.
[0008] Other objects, features, and advantage will be apparent to
persons of ordinary skill in the art from the following detailed
description of the invention and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] For a more complete understanding of the present invention,
needs satisfied thereby, and the objects, features, and advantages
thereof, reference now is made to the following description taken
in connection with the accompanying drawings.
[0010] FIG. 1 is a circuit diagram of a vapor compression
refrigerating system, according to an embodiment of the present
invention.
[0011] FIG. 2 is a Mollier chart of carbon dioxide refrigerant in
the vapor compression refrigerating system of FIG. 1.
[0012] FIG. 3 is a circuit diagram of a vapor compression
refrigerating system, according to another embodiment of the
present invention.
[0013] FIG. 4 is a Mollier chart of carbon dioxide refrigerant in
the vapor compression refrigerating system of FIG. 3.
[0014] FIG. 5 is an exemplary separator in which oil is separated
from refrigerant by centrifugal separation, in which FIG. 5A is a
vertical, sectional view of the separator; and FIG. 5B is a
cross-sectional view of the separator as viewed along line A-A of
FIG. 5A.
[0015] FIG. 6 is an exemplary separator in which oil is separated
from refrigerant by collision separation, in which FIG. 6A is a
vertical, sectional view of the separator; and FIG. 5B is a
cross-sectional view of the separator as viewed along line A-A of
FIG. 6A.
[0016] FIG. 7 is an exemplary refrigerant heat exchanging means in
a vapor compression refrigerating system, according to an
embodiment of the present invention, in which FIG. 7A is an
elevational view; FIG. 7B is a plan view thereof; and FIG. 7C is an
enlarged, sectional view of a tube for heat exchange thereof.
[0017] FIG. 8 is a perspective view of an exemplary refrigerant
heat exchanging means in a vapor compression refrigerating system,
according to another embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0018] Embodiments of the present invention, and their features and
advantages, may be understood by referring to FIGS. 1-8, like
numerals being used for like corresponding parts in the various
drawings.
[0019] FIG. 1 depicts a vapor compression refrigerating system
according to an embodiment of the present invention. The vapor
compression refrigerating system may comprise a compressor 1, a
radiator 2 connected to compressor 1, a first pressure reducing
mechanism 3 connected to radiator 2, and a separator 4 connected to
compressor 1 and to first pressure reducing mechanism 3. For
example, separator 4 may comprise an oil separator integrated with
a gas and liquid separator to form a single separator, and the
radiator 2 may be a gas cooler. The vapor compression refrigerating
system also may comprise a second pressure reducing mechanism 5
connected to separator 4, and an evaporator 6 connected to
compressor 1 and to second pressure reducing mechanism 5. Each of
the connections between the elements of the vapor compression
refrigerating system may be made via a tube 7.
[0020] In operation, a refrigerant, such as a carbon dioxide
refrigerant, may be compressed by compressor 1, which contracts the
refrigerant and increases the temperature of the refrigerant. The
refrigerant then may flow from compressor 1 to radiator 2, and
radiator 2 may radiate the refrigerant to decrease the temperature
of the refrigerant. The refrigerant then may flow from radiator 2
to first pressure reducing mechanism 3, and first pressure reducing
mechanism 3 may expand the refrigerant and may reduce the pressure
of the refrigerant. The refrigerant then may flow from first
pressure reducing mechanism 3 to separator 4, and separator 4 may
separate the refrigerant into a gas portion and a liquid portion,
and may separate an oil from the refrigerant. For example, the oil
may be separated from the refrigerant by centrifugal separation or
collision separation. The oil and the gas portion then may flow
from separator 4 to compressor 1, such that the oil and the gas
portion flow from separator 4 to compressor 1 via the same tube 7.
Nevertheless, the liquid portion may flow from separator 4 to
second pressure reducing mechanism 5, and second pressure reducing
mechanism 5 may further expand and further reduce the pressure of
the liquid portion. The liquid portion then may flow from second
pressure reducing mechanism 5 to evaporator 6, and evaporator 6 may
evaporate the liquid portion into a gas. The gas then may flow from
evaporator 6 to compressor 7.
[0021] In the above-described embodiment of the present invention,
because separator 4 may comprise an oil separator integrated with a
gas and liquid separator to form a single separator, and/or because
the gas portion of the refrigerant and the oil may flow from
separator 4 to compressor 1 via the same tube 7, the size and/or
the weight of the vapor compression refrigerating system may be
reduced.
[0022] FIG. 2 is a Mollier chart of carbon dioxide refrigerant in
the vapor compression refrigerating system of FIG. 1. In the
Mollier chart of FIG. 2, state points of the respective components
are connected to each other by lines. A curve 11 represents a
saturated liquid curve and a saturated vapor curve of carbon
dioxide refrigerant, and a curve connecting both lines is referred
to as a saturation curve. A curve 12 represents an isothermal line
passing through a critical point of carbon dioxide refrigerant.
Moreover, numerals labeled in FIG. 2 express the respective
components depicted in FIG. 1, and they show operations of the
respective components.
[0023] FIG. 3 depicts a vapor compression refrigerating system
according to another embodiment of the present invention. In this
embodiment, a refrigerant heat exchanging means, e.g., a heat
exchanging tube 8, is provided for exchanging heat between the
liquid refrigerant in separator 4 or/and the refrigerant which
flows out of separator 4, and the refrigerant which flows out of
evaporator 6. In this embodiment, super cooling is possible by
lowering the temperature of the refrigerant immediately before the
refrigerant flows to second pressure reducing mechanism 5.
Moreover, super heating is possible for preventing liquid
compression in compressor 1, and the refrigerating ability and the
reliability of the vapor compression refrigerating system may be
increased.
[0024] FIG. 4 is a Mollier chart of carbon dioxide refrigerant in
the vapor compression refrigerating system depicted in FIG. 3. In
the Mollier chart depicted in FIG. 4, state points of the
respective components are connected to each other by lines.
Similarly to FIG. 2, curve 11 represents a saturated liquid curve
and a saturated vapor curve of carbon dioxide refrigerant, and a
curve connecting both lines is referred to as a saturation curve. A
curve 12 represents an isothermal line passing through a critical
point of carbon dioxide refrigerant. One difference between FIGS. 2
and 4 is that there is an effect of heat exchange caused by the
heat exchange between liquid refrigerant in separator 4 and/or
refrigerant which flows out of separator 4, and refrigerant which
flows out of evaporator 6. Specifically, because the refrigerant
immediately before second pressure reducing mechanism 5 is the
liquid portion of the refrigerant, the liquid portion of the
refrigerant moves to a position above the saturation curve. In FIG.
4, .DELTA.h2 shows a degree of super cooling, .DELTA.ha shows a
degree of superheating, and the effect of heat exchange due to the
above-described refrigerant heat exchanging means may be expressed
as about .DELTA.h1 .quadrature..DELTA.h2.
[0025] Referring to FIGS. 5A and 5B, according to an embodiment of
the present invention, the separation of the refrigerant and the
oil is performed by a centrifugal separation system. For example,
the gas and liquid portion of the refrigerant may flow from first
pressure reducing mechanism 3 into the separator from a refrigerant
flow passage 22, and the refrigerant rotates in the circumferential
direction around a gas refrigerant and oil flow passage 22 to
compressor 1. Refrigerant and oil then are separated from each
other by the centrifugal force (centrifugal flow: 31).
Specifically, because the pressure of the refrigerant has been
reduced to a pressure which is less than the critical pressure, the
refrigerant and the oil are not dissolved in each other, and
because the density of oil is greater than the density of
refrigerant, the oil is stored in the lowest layer, which is an oil
layer 29. Moreover, the liquid portion of the refrigerant has a
greater density and is stored as a liquid refrigerant layer 28 at a
position above the oil layer 29, and the gas portion of the
refrigerant is present in a gas refrigerant layer 27, which is a
space above the liquid refrigerant layer 28, together with a small
amount of liquid refrigerant at a condition of gas/liquid mixture.
A refrigerant flow passage 23 to second pressure reducing mechanism
5 is positioned lower than oil layer 29, and an oil flowing out
prevention plate 30 is positioned above refrigerant flow passage
23, such that a fine amount of oil existing in liquid refrigerant
layer 28 does not flow out together with the liquid portion of the
refrigerant. The gas portion of the refrigerant in gas refrigerant
layer 27 passes through a diffuser or tube support 26, and liquid
present in the gas portion of the refrigerant is removed, such that
only gas refrigerant flows into oil flow passage 24 to compressor
1. At the same time, oil is sucked through an oil returning hole
25, and the sucked oil flows out together with the gas refrigerant.
Such a structure is contained in a container 21.
[0026] Referring to FIGS. 6A and 6B, according to an embodiment of
the present invention, the separation of the refrigerant and the
oil is performed by a collision separation system. For example, the
gas and liquid portion of the refrigerant may flow from first
pressure reducing mechanism into the separator from refrigerant
flow passage 22, and the refrigerant and the oil are separated from
each other by collision with diffuser or tube support 26 (collision
flow for separation: 32). Because diffuser or tube support 26 also
is provided in FIGS. 5A and 5B, and refrigerant and oil are
separated from each other by diffuser or tube support 26, the
structure depicted in FIGS. 5A and 5B is a structure in which the
centrifugal separation system is mainly employed and the collision
separation system is added thereto.
[0027] FIGS. 7A-7C show an example of a structure configured to be
employed in the system of FIG. 3, in which a heat exchanging tube
41, e.g., a flat tube, is provided at a storage part of liquid
refrigerant of separator 4 for exchanging heat between the
refrigerant present in separator 4 and the refrigerant which flows
from evaporator 6. Heat exchanging tube 41 may be wound at a tight
contact condition at the position and its vicinity of liquid
refrigerant layer 28 of separator 4, and heat exchange may be
performed. In this example, by forming heat exchanging tube 41 as a
parallel multi-hole flat tube 42, the efficiency of the heat
exchange may be improved. In such a structure, processing to the
container 21 with a pressure resistance may not be necessary.
[0028] FIG. 8 shows an example of another structure configured to
be employed in the system of FIG. 3, in which a heat exchanging
tube 51 having a double-pipe structure is used for heat exchanging
between the liquid portion of the refrigerant flowing into second
pressure reducing mechanism 5 from separator 4 and the refrigerant
which flows from evaporator 6. In heat exchanging tube 51, in order
to efficiently perform the heat exchange between the liquid
refrigerant portion flowing into second pressure reducing mechanism
5 from separator 4 and the refrigerant which flows from evaporator
6, both flows may be set as a counter flow or a parallel flow.
[0029] The vapor compression refrigerating system according to the
present invention may be particularly suitable for an air
conditioning system of a vehicle, such as an air conditioning
system which uses carbon dioxide as a refrigerant.
[0030] While the invention has been described in connection with
embodiments of the invention, it will be understood by those
skilled in the art that variations and modifications of the
embodiments described above may be made without departing from the
scope of the invention. Other embodiments will be apparent to those
skilled in the art from a consideration of the specification or
from a practice of the invention disclosed herein. It is intended
that the specification and the described examples are consider
exemplary only, with the true scope of the invention indicated by
the following claims.
* * * * *