U.S. patent application number 11/908450 was filed with the patent office on 2008-08-14 for accumulator integration with heat exchanger header.
This patent application is currently assigned to CARRIER COMMERCIAL REFRIGERATION, INC.. Invention is credited to Yu Chen, Hans-Joachim Huff, Tobias H. Sienel, Parmesh Verma.
Application Number | 20080190122 11/908450 |
Document ID | / |
Family ID | 37024268 |
Filed Date | 2008-08-14 |
United States Patent
Application |
20080190122 |
Kind Code |
A1 |
Huff; Hans-Joachim ; et
al. |
August 14, 2008 |
Accumulator Integration with Heat Exchanger Header
Abstract
A refrigeration system includes a compressor for driving a
refrigerant along a flow path in at least a first mode of system
operation; a first heat exchanger along the flow path downstream of
the compressor in the first mode; a second heat exchanger along the
flow path upstream of the compressor in the first mode; and an
expansion device in the flow path downstream of the first heat
exchanger and upstream of the second heat exchanger in the first
mode, wherein the second heat exchanger includes a combined header
and accumulator for collecting liquid and vapor refrigerant.
Inventors: |
Huff; Hans-Joachim; (West
Hartford, CT) ; Sienel; Tobias H.; (East Hampton,
MA) ; Chen; Yu; (East Hartford, CT) ; Verma;
Parmesh; (Manchester, CT) |
Correspondence
Address: |
BACHMAN & LAPOINTE, P.C. (UTC)
900 CHAPEL STREET, SUITE 1201
NEW HAVEN
CT
06510-2802
US
|
Assignee: |
CARRIER COMMERCIAL REFRIGERATION,
INC.
Charlotte
NC
|
Family ID: |
37024268 |
Appl. No.: |
11/908450 |
Filed: |
December 30, 2005 |
PCT Filed: |
December 30, 2005 |
PCT NO: |
PCT/US05/47574 |
371 Date: |
September 12, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60663911 |
Mar 18, 2005 |
|
|
|
Current U.S.
Class: |
62/118 ;
62/524 |
Current CPC
Class: |
F25B 2500/18 20130101;
F25B 9/008 20130101; F25B 2309/061 20130101; F25B 43/006 20130101;
F25B 5/02 20130101; F28D 1/0408 20130101; F25B 39/02 20130101; F28D
1/05366 20130101 |
Class at
Publication: |
62/118 ;
62/524 |
International
Class: |
F25D 17/00 20060101
F25D017/00; F25B 39/02 20060101 F25B039/02 |
Claims
1. A refrigeration system comprising: a compressor for driving a
refrigerant along a flow path in at least a first mode of system
operation; a first heat exchanger along the flow path downstream of
the compressor in the first mode; a second heat exchanger along the
flow path upstream of the compressor in the first mode; and an
expansion device in the flow path downstream of the first heat
exchanger and upstream of the second heat exchanger in the first
mode, wherein the second heat exchanger includes a combined header
and accumulator for collecting liquid and vapor refrigerant.
2. The system of claim 1 wherein the combined header and
accumulator comprises a chamber communicated with refrigerant flow
paths of the second heat exchanger for receiving two phase
refrigerant flow and defining therein a lower liquid refrigerant
zone and an upper vapor refrigerant zone.
3. The system of claim 2, wherein the lower liquid refrigerant zone
is defined below a lower most flow port between the second heat
exchanger and the combined header and accumulator.
4. The system of claim 3, wherein the lower most flow port is
positioned high enough above the lower liquid refrigerant zone that
the lower liquid refrigerant zone does not extend beyond the
evaporator.
5. The system of claim 1, wherein tubes of the second heat
exchanger flow directly into the combined header and
accumulator.
6. The system of claim 5, wherein a vapor flow line is connected
directly from the combined header and accumulator to the
compressor.
7. The system of claim 2 further comprising a conduit communicated
with the upper vapor refrigerant zone for conveying vapor
refrigerant to the compressor.
8. The system of claim 7, wherein the conduit extends upwardly
through the liquid refrigerant zone into the vapor refrigerant
zone, and is also communicated with the liquid refrigerant
zone.
9. The system of claim 8, wherein the conduit is communicated with
the liquid refrigerant zone through a pin-hole to allow oil to
return to the compressor.
10. The system of claim 1 wherein: the refrigerant comprises, a
transcritical vapor system refrigerant and wherein the first and
second heat exchangers are refrigerant-air heat exchangers.
11. A beverage cooling device comprising the system of claim 1.
12. A method for operating a refrigeration system comprising
operating a compressor to drive a refrigerant along a flow path,
sequentially, to a first heat exchanger, an expansion device, a
second heat exchanger, a combined header and accumulator, and back
to the compressor, wherein flow is directly from the second heat
exchanger to the combined header and accumulator, and wherein flow
is directly from the combined header and accumulator to the
compressor.
13. The method of claim 12, wherein the second heat exchanger
comprises a flow tube, wherein operation of the compressor creates
two-phase refrigerant in the flow tube, and wherein the two-phase
refrigerant flows directly to the combined header and
accumulator.
14. The method of claim 12, wherein the refrigerant is a
transcritical vapor system refrigerant.
15. The method of claim 12, wherein the refrigerant is
CO.sub.2.
16. The method of claim 12, wherein the combined header and
accumulator defines a lower liquid refrigerant zone and an upper
vapor refrigerant zone, and wherein flow of refrigerant into the
combined header and accumulator causes separation of the
refrigerant into a liquid refrigerant in the lower liquid
refrigerant zone and vapor refrigerant in the upper vapor
refrigerant zone.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of the filing date of
earlier filed Provisional Application Ser. No. 60/663,911 filed
Mar. 18, 2005. Further, copending application docket 05-258-WO,
entitled HIGH SIDE PRESSURE REGULATION FOR TRANSCRITICAL VAPOR
COMPRESSION SYSTEM and filed on even date herewith, and the
aforesaid Provisional Application Ser. No. 60/663,911 disclose
prior art and inventive cooler systems. The disclosure of said
application is incorporated by reference herein as if set forth at
length.
BACKGROUND OF THE INVENTION
[0002] In many refrigeration applications space is a limited
resource. Any reduction in space requirements for the refrigeration
system application can improve the overall design of the
system--either by reducing the overall size or by utilizing the
space that becomes available for other purposes, such as increased
heat exchanger area. Thus, a consolidated component design can
reduce system cost and increase system performance.
[0003] FIG. 1 shows a prior art vapor compression system having a
compressor 1, a gas cooler 2, an expansion device 3, and an
evaporator 4. In evaporator 4, refrigerant passes through a series
of heat exchanger tubes 5 in a heat exchange relationship with air
being cooled as desired. Refrigerants typically enters tubes 5
through a header 6 and exits tubes 5 into a header 7. Refrigerant
collected in header 7 then flows to an accumulator 8 where liquid
phase refrigerant and oil separate from vapor phase refrigerant,
and vapor is drawn back to compressor 1.
[0004] While the system illustrated in FIG. 1 is functional, as set
forth above, a functional system which occupies less space is
desirable.
[0005] It is therefore the primary object of the present invention
to provide such a system.
[0006] Other objects and advantages will appear herein.
SUMMARY OF THE INVENTION
[0007] A refrigeration system is provided which includes a
compressor for driving a refrigerant along a flow path in at least
a first mode of system operation; a first heat exchanger along the
flow path downstream of the compressor in the first mode; a second
heat exchanger along the flow path upstream of the compressor in
the first mode; and an expansion device in the flow path downstream
of the first heat exchanger and upstream of the second heat
exchanger in the first mode, wherein the second heat exchanger
includes a combined header and accumulator for collecting liquid
and vapor refrigerant. The combined header and accumulator serves
to conserve space which is particularly advantageous, for example
in transcritical vapor compression systems.
[0008] A method is also provided for operating a refrigeration
system in accordance with the present invention, which method
comprises operating a compressor to drive a refrigerant along a
flow path, sequentially, to a first heat exchanger, an expansion
device, a second heat exchanger, a combined header and accumulator,
and back to the compressor, wherein flow is directly from the
second heat exchanger to the combined header and accumulator, and
wherein flow is directly from the combined header and accumulator
to the compressor.
BRIEF DESCRIPTION OF THE DRAWING
[0009] A detailed description of preferred embodiments of the
present invention follows, with reference to the attached drawings,
wherein:
[0010] FIG. 1 is an illustration of a prior art vapor compression
system;
[0011] FIG. 2 is a schematic illustration of a system having a
combined accumulator and header according to the invention;
[0012] FIG. 3 is a schematic illustration of an alternative
embodiment of the combined accumulator and header according to the
invention; and
[0013] FIG. 4 is a schematic illustration of a further alternative
embodiment of the combined accumulator and header in accordance
with the present invention.
DETAILED DESCRIPTION
[0014] The invention relates to a heat exchanger configuration for
a vapor compression system and, more particularly, to a
space-saving combination of the refrigerant accumulator and the
heat exchanger header in a transcritical vapor compression cycle.
In transcritical vapor compression systems, heat rejection occurs
at a pressure above the critical pressure of the refrigerant.
During the heat rejection the refrigerant does not condense. The
charge management in a transcritical system is usually accomplished
by adding an accumulator to the evaporator outlet, following an
outlet header (See FIG. 1).
[0015] FIG. 2 shows the vapor compression system 10 in accordance
with the present invention which includes a compressor 12, a first
heat exchanger or gas cooler 14, an expansion device 16 and a
second heat exchanger or evaporator 18. As compared to FIG. 1, it
should be readily appreciated that evaporator 18 includes an inlet
header 20 as in conventional devices, but that evaporator 18 also
includes a combined header and accumulator 22 which combines the
functions of separate outlet header 7 and accumulator 8 as
illustrated in FIG. 1. This advantageously allows for conservation
of space while providing the desired functions of both the header
and the accumulator of this device.
[0016] As shown in FIG. 2, combined header and accumulator 22 in
accordance with the present invention is a single chamber which
defines a lower liquid refrigerant zone 24 and an upper vapor
refrigerant zone 26. Flow enters the combined header and
accumulator 22 directly from tubes 28 of second heat exchanger 18.
In this regard, it is noted that FIG. 2 shows lower liquid
refrigerant zone 24 defined at a location which is lower than the
inlet from the lower most tube 30. This advantageously prevents
masking and/or back-flow of liquid refrigerant with respect to
lower most tube 30. As shown in FIG. 2, this chamber is defined by
side, front, back, top and bottom walls around the end of the heat
exchanger tubes.
[0017] Also as shown in FIG. 2, combined header and accumulator 22
advantageously has an inner conduit 32 which extends from a bottom
surface of combined accumulator and header 22 upwardly above the
expected liquid level of liquid within lower liquid refrigerant
zone 24. Compressor 12 draws vapor phase refrigerant out of vapor
refrigerant zone 26 and through conduit 32 to the compressor
suction line.
[0018] A lower portion 34 of conduit 32 is preferably provided with
a pin hole 36 which advantageously allows oil within the lower
liquid refrigerant zone 24 to be drawn back to compressor 12 as
desired.
[0019] The heat exchangers 14, 18 of the present invention can be
provided as any known type of heat exchanger, preferably as
refrigerant-air heat exchangers. Specific examples of suitable heat
exchangers include but are not limited to wire on tube heat
exchangers, fin heat exchangers, and the like.
[0020] The system of the present invention is particularly well
suited to a transcritical vapor compression system, for example, a
system which uses CO.sub.2 as working fluid. Of course, other
refrigerants, particularly those with similar properties to
CO.sub.2 under expected operating conditions, can be used and are
considered to be well within the broad scope of the present
invention.
[0021] Expansion device 16 can be any suitable expansion device
known to a person of skill in the art. A pressure regulator, for
example a pressure regulator such as that disclosed in commonly
owned and simultaneously filed PCT Application bearing attorney
docket number 05-258-WO and entitled HIGH SIDE PRESSURE REGULATION
FOR TRANSCRITICAL VAPOR COMPRESSION SYSTEM, is also well within the
scope of the present invention and is considered to be an expansion
device as used herein.
[0022] Header and accumulator 22 can advantageously be incorporated
into heat exchanger 18 as shown in FIG. 2. Alternatively, header
and accumulator 22 can be a separate structure defining a chamber
and communicated with heat exchanger 18, preferably through direct
flow from tubes of the heat exchanger into the chamber.
[0023] FIG. 3 shows a further alternative embodiment of the present
invention, having the same basic components as the embodiment of
FIG. 2. In the embodiment of FIG. 3, evaporator 18 is divided into
two components 38, 40, and combined header and accumulator 22 is
connected to each component 38, 40 through a short flow conduit 42.
In this embodiment, it should be noted that by positioning lower
most tube 30 sufficiently high on second heat exchanger 18, the
lower liquid refrigerant zone 24 can be defined within combined
accumulator and header 22 so that a bottom surface 44 of combined
accumulator and header 22 does not extend substantially beyond a
bottom surface 46 of second heat exchanger 18. Conduit 42 is
preferably very short, most preferably having a length of less than
about 5 inches.
[0024] FIG. 4 shows a further embodiment of the present invention,
wherein system 10 includes the same components as those described
in connection with FIGS. 2 and 3. With the embodiment of FIG. 4,
refrigerant fed from expansion device 16 to evaporator 18 flows
through a single conduit 48 to combined header and accumulator 22
in accordance with the present invention. From this point, vapor
phase refrigerant is drawn back to compressor 12 as desired.
[0025] Embodiments of the invention as indicated in FIGS. 2-4 of
the present invention integrate the accumulator and the evaporator
outlet header into a single chamber. This single chamber performs
the function of both the header and accumulator of the conventional
system of FIG. 1. Advantageously, the functions normally performed
in the separate header and accumulator are now performed in the
same space. This design reduces the space requirements for the
accumulator as well as the overall tubing length and the number of
tube connections.
[0026] Two-phase flow leaving the evaporator is separated in the
header. The liquid refrigerant is collected by gravity at the
bottom of the accumulator-header. The vapor leaves the accumulator
header through the tube inserted into the header. The tube has a
pin-hole in the accumulator section of the header to allow oil
return to the compressor.
[0027] One or more embodiments of the present invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. For example, when implemented as a
remanufacturing of an existing system or reengineering of an
existing system configuration, details of the existing
configuration may influence details of the implementation.
Accordingly, other embodiments are within the scope of the
following claims.
* * * * *