U.S. patent application number 14/431078 was filed with the patent office on 2015-09-03 for low refrigerant high performing subcooler.
The applicant listed for this patent is TRANE INTERNATIONAL INC.. Invention is credited to Ronald Maurice Cosby, II, Wade Bin Liu.
Application Number | 20150247658 14/431078 |
Document ID | / |
Family ID | 50386789 |
Filed Date | 2015-09-03 |
United States Patent
Application |
20150247658 |
Kind Code |
A1 |
Cosby, II; Ronald Maurice ;
et al. |
September 3, 2015 |
LOW REFRIGERANT HIGH PERFORMING SUBCOOLER
Abstract
A refrigerant displacement device is used to reduce subcooler
refrigerant charge while enhancing heat transfer performance, e.g.
by maintaining and/or increasing subcooler performance. The
refrigerant displacement device physically takes up volume of the
subcooler that would normally be occupied by refrigerant. The
refrigerant displacement device can be a baffle structure with
orifices through which the subcooler's heat exchange tubes are
allowed to be inserted. Refrigerant is still allowed, however, to
flow through the remaining volume of the subcooler and through
openings constructed as, e.g. annuluses, between the tube(s) and
the refrigerant displacement device, so as to allow refrigerant
flow from an inlet of the subcooler to an outlet of the
subcooler.
Inventors: |
Cosby, II; Ronald Maurice;
(LaCrosse, WI) ; Liu; Wade Bin; (Shanghai,
CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TRANE INTERNATIONAL INC. |
Piscataway |
NJ |
US |
|
|
Family ID: |
50386789 |
Appl. No.: |
14/431078 |
Filed: |
September 26, 2012 |
PCT Filed: |
September 26, 2012 |
PCT NO: |
PCT/CN2012/081990 |
371 Date: |
March 25, 2015 |
Current U.S.
Class: |
62/119 ; 165/159;
62/506 |
Current CPC
Class: |
F25B 40/02 20130101;
F25B 41/00 20130101; F28D 7/163 20130101; F28D 1/05325 20130101;
F25B 39/04 20130101; F28F 9/22 20130101; F25B 2339/046
20130101 |
International
Class: |
F25B 39/04 20060101
F25B039/04; F25B 40/02 20060101 F25B040/02; F25B 41/00 20060101
F25B041/00; F28D 1/053 20060101 F28D001/053 |
Claims
1. A refrigerant displacement device suitable for use in a
subcooler of an HVAC unit, comprising one or more baffles, each
baffle includes: a main body suitable to be placed inside a
subcooler, along a direction that heat exchange tubes would extend
inside the subcooler, the main body is configured to physically
prevent refrigerant from occupying volume or free flow areas within
the subcooler that would otherwise be occupied by refrigerant; a
number of orifices extending through the main body, and through
which heat exchange tubes may be suitably inserted; and one or more
standoffs to create space between an outer diameter of heat
exchange tubes inserted through the orifices and surfaces on the
baffle created by the orifices, wherein during unit, system, and/or
component operation, refrigerant is allowed to flow through the
orifices between the baffle and the heat exchange tubes, and
refrigerant is directed to flow proximate the heat exchange
tubes.
2. The device of claim 1, wherein the device is constructed and
arranged as a series of baffles, each of the baffles had the same
or different depth.
3. The device of claim 1, wherein the baffle is a single extrusion
that extends along a majority of the length through subcooler.
4. An HVAC system comprising: a condenser; a subcooler as part of
the condenser; and the refrigerant displacement device of claim 1
suitably incorporated inside the subcooler, wherein the subcooler
is constructed as a discrete envelopment inside the condenser or is
constructed by utilizing a portion of the condenser shell
walls.
5. (canceled)
6. A method of operating a subcooler in an HVAC unit or system,
comprising: causing refrigerant to enter an inlet of a subcooler;
causing the refrigerant to flow through orifices of a refrigerant
displacement device; causing the refrigerant to be directed by the
refrigerant displacement device to flow proximate the heat exchange
tubes in areas between surfaces of the baffle created by the
orifices and the outer surface of the heat exchange tubes; causing
refrigerant to not be physically present at areas in the subcooler
that are away from the heat exchange tubes and toward the enclosure
of the subcooler, and not proximate the heat exchange tubes; and
subcooling the refrigerant, while reducing refrigerant charge
through the subcooler and increasing flow velocity proximate the
heat exchange tubes.
7. The method of claim 6, further comprises causing the refrigerant
to flow through annularly shaped spaces created by standoffs on the
orifices of the baffle, so that refrigerant flows between the
orifices of the baffle and heat exchange tubes inserted therein.
Description
FIELD
[0001] The disclosure herein relates to heating, ventilation, and
air-conditioning ("HVAC") applications, systems and methods, and
more particularly to a subcooler with a refrigerant displacement
device that can be suitable for use with a condenser in HVAC
components, units, and systems.
BACKGROUND
[0002] Subcoolers are known to be used in shell and tube heat
exchangers, such as in condensers of water cooled HVAC chillers and
that operate under the condensing temperature. Subcooler design is
typically dictated by heat exchange tube geometry size and shell
size allowance within the shell and tube heat exchanger.
[0003] Existing subcooler designs can be separate enclosures
ranging from, for example discrete envelopments within a condenser
shell, to separate welded enclosures within the condenser
shell.
[0004] Other subcooler designs that may not utilize a separate
enclosure, and may instead use part of the condenser shell walls as
part of the subcooler enclosure.
SUMMARY
[0005] Such subcooler designs that may be discrete envelopments as
described above are often welded enclosures to prevent leakage and
bypass. The costs of such subcooler designs can be high. Such
subcooler designs described above that may utilize the condenser
shell walls as part of the subcooler enclosure can have relatively
more refrigerant charge than discrete envelopment designs, and can
have significantly more flow area/reduced flow velocities. Also,
future refrigerant taxes and/or higher prices with new alternative
refrigerants may restrict the construction of such designs that
utilize portions of the condenser shell wall. Additionally, where
there may be reduced flow velocities, subcooler performance may
suffer and require additional tube surface area to accommodate the
lack of heat transfer performance.
[0006] A refrigerant displacement device as described herein and
shown in the Figures can address performance and cost issues that
may be associated with such existing subcooler designs as described
above, by not only minimizing refrigerant charge through the
subcooler, but also minimizing the free flow area to increase flow
velocity over the subcooler tubes.
[0007] In one embodiment, a refrigerant displacement device is a
baffle structure that includes a main body that is suitable to be
placed into a subcooler, for example along the direction that heat
exchange tubes extend, e.g. in an end to end or lengthwise
direction/arrangement. The main body physically displaces
refrigerant from volume or free flow areas within the enclosure of
the subcooler that would otherwise be occupied by refrigerant. The
main body has a number of orifices through the main body, and
through which heat exchange tubes may be suitably inserted. The
orifices have a standoff(s) to create space between an outer
diameter of the heat exchange tubes and surfaces on the baffle
created by the orifices. During unit, system, component operation,
refrigerant is allowed to flow through the orifices between the
baffle and the heat exchange tubes, and refrigerant is directed to
flow proximate the heat exchange tubes.
[0008] In one embodiment, the displacement device can be a series
of baffles, where each of the baffles may have a different depth
(e.g. dimension along the tube length), or in some embodiments can
be one extrusion or a few larger extruded pieces. In some
embodiments, whether there is a series of baffles, extruded pieces,
or single extrusion, the refrigerant displacement device can extend
along a majority or about all of the heat exchange tube length
running through subcooler.
[0009] In one embodiment, the refrigerant displacement device can
be suitably incorporated into HVAC system, for example into a
condenser. In some embodiments, the refrigerant displacement device
can be suitably incorporated into a subcooler with a dedicated,
discrete envelopment. In some embodiments, the refrigerant
displacement device the refrigerant displacement device can be
suitably incorporated into a subcooler that utilizes a portion of
the condenser shell walls.
[0010] In one embodiment, a method of operating a subcooler in a
condenser of an HVAC unit or system includes: causing refrigerant
to enter an inlet of a subcooler; causing the refrigerant to flow
through orifices of a refrigerant displacement device; causing the
refrigerant to be directed by the refrigerant displacement device
to flow proximate the heat exchange tubes in areas between surfaces
of the baffle created by the orifices and the outer surface of the
heat exchange tubes; causing refrigerant to not be physically
present at areas in the subcooler that are away from the heat
exchange tubes and toward the enclosure of the subcooler, and not
proximate the heat exchange tubes; and subcooling the refrigerant,
while reducing refrigerant charge through the subcooler and
increasing flow velocity proximate the heat exchange tubes.
[0011] In some embodiments, the method further comprises causing
the refrigerant to flow through annularly shaped spaces created by
standoffs on the orifices of the baffle, so that refrigerant flows
between the orifices of the baffle and heat exchange tubes inserted
therein.
[0012] Other features and aspects of the systems, methods, and
control concepts will become apparent by consideration of the
following detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Reference is now made to the drawings in which like
reference numbers represent corresponding parts throughout.
[0014] FIG. 1 is an end view one embodiment of a refrigerant
displacement device, and schematically showing a depth from end to
end that can vary.
[0015] FIG. 2 is an open end schematic view of a condenser of an
HVAC system with a subcooler utilizing a portion of the condenser
shell walls as the subcooler enclosure.
[0016] FIG. 3 is an open end schematic view of another condenser of
an HVAC system with a subcooler as a separate discreet
enclosure.
[0017] FIG. 4 shows a schematic side view of a refrigerant
displacement device installed in a subcooler.
DETAILED DESCRIPTION
[0018] A refrigerant displacement device is described and shown in
the Figures that can address performance and cost issues that may
be associated with such existing subcooler designs as described
above, by not only minimizing refrigerant charge through the
subcooler, but also minimizing the free flow area to increase flow
velocity over the subcooler tubes. Generally, the refrigerant
displacement device is a baffle structure or construction and
arrangement of a series of baffles that are suitable for use in a
subcooler.
[0019] The utilization of one or more refrigerant displacement
baffles allows for minimization of refrigerant but also helps to
focus high velocity refrigerant flow proximate to and around the
heat exchange tubes to conduct heat away from the refrigerant into
the cooling fluid inside the heat exchange tubes. Refrigerant
charge can be reduced, and/or chiller efficiency can increase,
and/or copper tubing costs can be saved. The refrigerant
displacement device herein can allow for the flexibility in any
type of subcooler, e.g. discrete envelope designs and designs that
use a portion of the condenser shell wall as the subcooler
enclosure, by utilizing a refrigerant displacement device, such as
baffle(s), to reduce refrigerant charge through displacement. The
refrigerant displacement device can also enhance heat transfer
performance within the subcooler by minimizing flow areas and
focusing refrigerant flow within a flow annulus around the
subcooler tubing.
[0020] The refrigerant displacement device can be utilized in a
subcooler, for example in a condenser of a water cooled chiller or
HVAC unitary product, where the refrigerant displacement device is
a physical structure, such as one or more displacing baffles.
[0021] FIG. 1 is an end view one embodiment of a refrigerant
displacement device, and also schematically showing a depth from
end to end that can vary.
[0022] The refrigerant displacement device may be one or more
baffles. An exemplary baffle "A" is shown in FIG. 1 that may be
used in a refrigerant displacement device. The baffle A is shown
for example from a side as if it were inserted into a chiller and
if the view of the chiller was taken from an end. The baffle A has
a structure 1 that physically prevents refrigerant from occupying
certain spaces inside the subcooler when the baffle A is installed.
As shown, the baffle A has a number of orifices 2 through which
heat exchange tubes can be inserted. The orifices have protrusions
or standoffs 4 that allow for space, such as an annulus or annular
shape, to be present between an outer surface of a heat exchange
tube that may inserted through the orifices 2 and the inner
diameter or circumferential-like wall of the orifices 2. The
protrusions 4 define the amount of space between orifice and the
heat exchange tubes and could be modified as appropriate to achieve
certain flow velocities and amount of subcooling needed/desired,
The shape, geometry, and actual dimensions of the baffle A, its
orifices 2, its protrusions 4, or its overall structure 1 are not
meant to be limiting. One or more of baffles A can be inserted
within the subcooler as an array to provide displacement of
refrigerant (to minimize dead space, decrease free flow area within
the subcooler) and to focus refrigerant flow proximate and around
the heat exchange tubes to help with heat exchange performance,
e.g. by increasing flow velocities near and around the heat
exchange tubes, which can increase the refrigerant side heat
transfer coefficient and decrease the amount of subcooler heat
transfer that may be required, which can reduce copper tube surface
area.
[0023] The refrigerant displacement device can be a series or array
of baffles, where each baffle has a depth from end to end, e.g.
such as when viewing perpendicularly into the page of FIG. 1. In
some embodiments, depth "D" (see also e.g. dashed lines and double
arrows in FIG. 1) can be varied to achieve the desired, needed size
of the baffle along the length of the heat exchange tubes. The
depth "D" that is shown is merely illustrative and not meant to be
limiting. It will be appreciated that the depths can be varied. It
will also be appreciated that the baffle could be a single extruded
piece, rather than a series of baffles, that spans much of the tube
length within the subcooler (see e.g. FIG. 4 further described
below). It will also be appreciated that the baffle does not have
to be a single extrusion, but could be a dual extrusion or just a
few extruded pieces to account for other subcooler structures, e.g.
the position of inlet/outlet structures into/out of the subcooler.
It will further be appreciated that the baffles pieces that may be
used could have common interlocking structures to allow baffles to
be linked together and to create multiple subcooler cross sectional
geometries, for example by having suitable press fit structures, or
suitable fastening capability, or may be connected by epoxy or
using interlocking modules similar to e.g. LEGO toys. And it will
also be appreciated that not all of the tubes in the subcooler must
be inserted through the baffle as it may be desired and/or
necessary. One example of the baffle material could be a composite
or plastic material, such as polypropylene. The material of the
refrigerant displacement device is generally not meant to be
limiting, although HVAC system friendly and refrigerant friendly,
non-corrosive materials may be preferred. A screen may also be used
to block debris from flowing through the subcooler, such as on an
inlet and/or outlet of the subcooler.
[0024] FIG. 2 shows one type of condenser 10 with a subcooler "B"
that has heat exchange tubes 6 where its enclosure 8 is formed by
utilizing the wall(s) of the condenser shell and perhaps other
pieces of the condenser, such as a drain pan and/or inlet/outlet
structures. An outlet 5 from the subcooler B is also shown. It will
be appreciated that a suitable inlet into the subcooler B would be
employed to allow refrigerant to flow inside the subcooler B, for
example from the bottom or on sides of the subcooler B.
[0025] FIG. 3 is an open end schematic view of another condenser of
an HVAC system with a subcooler as a separate discreet enclosure.
FIG. 3 shows condenser 20 with a subcooler "C" that has heat
exchange tubes 16 where its enclosure 18 formed as a separate
discreet enclosure that may be welded to the condenser shell. An
outlet 15 from the subcooler C is also shown, It will be
appreciated that a suitable inlet into the subcooler C would be
employed to allow refrigerant to flow inside the subcooler C, for
example from the bottom or on sides of the subcooler C.
[0026] It will be appreciated that the refrigerant displacement
device may be incorporated into either of the subcooler designs B
and/or C from FIGS. 2 and 3.
[0027] FIG. 4 shows a schematic side view of a condenser 30 that
has a subcooler 34, with a refrigerant displacement device 32
installed in the subcooler 34. Heat exchange tubes or tube bundle
36 (see dashed line) can be inserted through the refrigerant
displacement device 32, e.g. through orifices and protrusions
similarly constructed as in FIG. 1. FIG. 4 is to schematically show
an example of the relative area and coverage of the refrigerant
displacement device 32 inside the subcooler 34. For example using
one or more pieces, such as extrusion(s), the refrigerant
displacement device 32 can extend the majority or almost the entire
length of the subcooler 34 and have coverage on most of the tube
bundle 36. It will be appreciated that the refrigerant displacement
device A can be constructed and arranged as that in FIG. 4.
[0028] Although the refrigerant displacement device is discussed in
the context of a condenser, it will be appreciated that it may be
useful for any shell and tube subcooler design, and any HVAC unit
and/or system as appropriate, and which may not include a
condenser.
[0029] With regard to the foregoing description, it is to be
understood that changes may be made in detail, without departing
from the scope of the present invention. It is intended that the
specification and depicted embodiments are to be considered
exemplary only, with a true scope and spirit of the invention being
indicated by the broad meaning of the claims.
* * * * *