U.S. patent application number 15/356233 was filed with the patent office on 2018-05-24 for hybrid heat exchanger.
The applicant listed for this patent is Hussmann Corporation. Invention is credited to Paul R. Laurentius.
Application Number | 20180142957 15/356233 |
Document ID | / |
Family ID | 62146736 |
Filed Date | 2018-05-24 |
United States Patent
Application |
20180142957 |
Kind Code |
A1 |
Laurentius; Paul R. |
May 24, 2018 |
HYBRID HEAT EXCHANGER
Abstract
A heat exchanger includes a coil having bends and tube passes
disposed between the bends. The coil further has an inlet end and
an outlet end and being continuous between the inlet end and the
outlet end. The coil is defined by parallel microchannel
passageways extending from the inlet end to the outlet end. The
heat exchanger also includes a plurality of elongated fins spaced
apart from each other between a first end of the heat exchanger and
a second end of the heat exchanger. Each of the fins defines two or
more apertures, wherein two or more of the tube passes extend
through the same fin of the plurality of fins.
Inventors: |
Laurentius; Paul R.;
(Bridgeton, MO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hussmann Corporation |
Bridgeton |
MO |
US |
|
|
Family ID: |
62146736 |
Appl. No.: |
15/356233 |
Filed: |
November 18, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25B 39/02 20130101;
F28F 2260/02 20130101; A47F 3/001 20130101; F28F 19/006 20130101;
F28D 2021/0071 20130101; F28F 2210/10 20130101; F28D 1/0478
20130101; F28F 1/325 20130101; F28D 2001/0266 20130101 |
International
Class: |
F28D 1/047 20060101
F28D001/047; F28F 1/32 20060101 F28F001/32; F28F 19/00 20060101
F28F019/00 |
Claims
1. A heat exchanger comprising: a coil having bends and tube passes
disposed between the bends, the coil further having an inlet end
and an outlet end and being continuous between the inlet end and
the outlet end, and the coil defined by parallel microchannel
passageways extending from the inlet end to the outlet end; and a
plurality of elongated fins spaced apart from each other between a
first end of the heat exchanger and a second end of the heat
exchanger, each of the fins defining two or more apertures, wherein
two or more of the tube passes extend through the same fin of the
plurality of fins.
2. The heat exchanger of claim 1, wherein each of the tube passes
has a substantially rectangular cross-section, and wherein the
apertures in each of the fins conforms to the shape of tube
passes.
3. The heat exchanger of claim 1, wherein a plane defined by each
tube pass is oriented at a non-zero angle relative to a vertical
plane and relative to a horizontal plane.
4. The heat exchanger of claim 1, wherein the tube passes are
elongated across a width of the tube passes, and wherein at least
two of the tube passes are oriented parallel to each other in a
plane defined by the elongated direction.
5. The heat exchanger of claim 1, wherein the coil is a first coil
of the heat exchanger and the heat exchanger further includes a
second coil having bends and tube passes disposed between the bends
of the second coil, the second coil further having an inlet end and
an outlet end and being continuous between the inlet end and the
outlet end of the second coil, and the second coil defined by
parallel fluid passageways extending from the inlet end to the
outlet end.
6. The heat exchanger of claim 5, wherein the first coil defines a
first circuit of the heat exchanger and the second coil defines a
second circuit of the heat exchanger that is separate from the
first circuit.
7. The heat exchanger of claim 5, wherein a plane defined by at
least one of the tube passes of the second coil is oriented
non-parallel to a plane defined by at least one of the tube passes
of the first coil.
8. The heat exchanger of claim 5, further comprising an inlet
manifold and an outlet manifold, wherein each of the first coil and
the second coil is in fluid communication with and coupled to the
inlet manifold and the outlet manifold.
9. The heat exchanger of claim 1, wherein the coil includes a first
tube pass defining a first plane and a second tube pass
interconnected to the first tube pass by a bend and defining a
second plane, and wherein the second plane is non-parallel relative
to the first plane.
10. A heat exchanger comprising: a serpentine coil having an inlet
end and an outlet end and being continuous between the inlet end
and the outlet end, and the serpentine coil defined by parallel
fluid passageways extending from the inlet end to the outlet end;
and one or more fins disposed between a first end of the heat
exchanger and a second end of the heat exchanger, wherein each of
the one or more fins is coupled to different portions of the
serpentine coil.
11. The heat exchanger of claim 10, wherein each of the one or more
fins defines two or more apertures through which the serpentine
coil extends.
12. The heat exchanger of claim 11, wherein the serpentine coil has
a substantially rectangular cross-section, and wherein the
apertures in each of the fins conform to the shape of tube
passes.
13. The heat exchanger of claim 10, wherein the serpentine coil
includes a plurality of tube passes oriented at a non-zero angle
relative to a vertical plane and relative to a horizontal
plane.
14. The heat exchanger of claim 13, wherein the tube passes are
elongated across a width of the tube passes, and wherein at least
two of the tube passes are oriented parallel to each other in a
plane defined by the elongated direction.
15. The heat exchanger of claim 10, wherein the coil is a first
coil of the heat exchanger and the heat exchanger further includes
a second serpentine coil having an inlet end and an outlet end and
being continuous between the inlet end and the outlet end of the
second coil, wherein the second coil is defined by parallel fluid
passageways extending from the inlet end to the outlet end of the
second coil.
16. The heat exchanger of claim 15, wherein a plane defined by at
least one of the tube passes of the second coil is oriented
non-parallel to a plane defined by at least one of the tube passes
of the first coil.
17. The heat exchanger of claim 15, further comprising an inlet
manifold and an outlet manifold, wherein each of the first coil and
the second coil is in fluid communication with and coupled to the
inlet manifold and the outlet manifold.
18. The heat exchanger of claim 10, wherein the coil includes a
first tube pass and a second tube pass interconnected by a bend,
and wherein the second tube pass is non-parallel with the first
tube pass.
19. A heat exchanger comprising: a coil having bends and tube
passes disposed between the bends, the coil further having an inlet
end and an outlet end and being continuous between the inlet end
and the outlet end, and the coil defined by parallel microchannel
passageways extending from the inlet end to the outlet end; and a
plurality of fins spaced apart from each other between a first end
of the heat exchanger and a second end of the heat exchanger,
wherein each of the plurality of fins is coupled to and surrounds
multiple tube passes of the coil.
20. The heat exchanger of claim 19, wherein at least one of the
tube passes lies in and defines a first plane, and another of the
tube passes lies in and defines a second plane that is non-parallel
relative to the first plane.
21. The heat exchanger of claim 1, wherein the coil is positioned
in a refrigerated merchandiser including a product display area,
and wherein the coil is configured to cool an airflow directed
toward the product display area.
22. The heat exchanger of claim 10, wherein the coil is positioned
in a refrigerated merchandiser including a product display area,
and wherein the coil is configured to cool an airflow directed
toward the product display area.
23. The heat exchanger of claim 19, wherein the coil is positioned
in a refrigerated merchandiser including a product display area,
and wherein the coil is configured to cool an airflow directed
toward the product display area.
Description
[0001] The present invention relates to a heat exchanger, and more
particularly, to a heat exchanger including fins and one or more
microchannel coils.
BACKGROUND
[0002] Refrigeration systems are well known and widely used in
supermarkets and warehouses to refrigerate food product displayed
in a product display area of a refrigerated merchandiser or display
case. Conventional refrigeration systems often include an
evaporator, a compressor, and a condenser connected in series. The
evaporator provides heat transfer between a refrigerant and a fluid
passing over the evaporator coil. The evaporator transfers heat
from the fluid to the refrigerant so that the fluid cools the
product display area. The refrigerant absorbs heat from the fluid
in a refrigeration mode, and the compressor mechanically compresses
the evaporated refrigerant from the evaporator and feeds the
superheated refrigerant to the condenser, which cools the
refrigerant via heat transfer between the condenser coil and a
fluid (typically ambient air) flowing through the condenser. From
the condenser, the cooled refrigerant is fed through one or more
expansion valves to reduce the temperature and pressure of the
refrigerant, and then the refrigerant is directed through the
evaporator.
[0003] Commercial refrigerators use heat exchangers for the purpose
of absorbing heat from the air stream to reduce the temperature of
the air and use that air mass to cool product. In most
below-freezing applications this is done with a traditional fin and
tube design. On the condensing side of the system, microchannel
coils are becoming increasingly more common, but due to fin density
and design the microchannel coils ice over rapidly in
below-freezing applications.
SUMMARY
[0004] In one construction, the invention embodies a heat exchanger
including a coil that has bends and tube passes that are disposed
between the bends. The coil further has an inlet end and an outlet
end and is continuous between the inlet end and the outlet end. The
coil is defined by parallel microchannel passageways extending from
the inlet end to the outlet end. The heat exchanger also includes a
plurality of elongated fins spaced apart from each other between a
first end of the heat exchanger and a second end of the heat
exchanger. Each of the fins defines two or more apertures, and two
or more of the tube passes extend through the same fin of the
plurality of fins.
[0005] In another construction, the invention embodies a heat
exchanger including a serpentine coil that has an inlet end and an
outlet end and that is continuous between the inlet end and the
outlet end. The serpentine coil is defined by parallel fluid
passageways extending from the inlet end to the outlet end. The
heat exchanger also includes one or more fins disposed between a
first end of the heat exchanger and a second end of the heat
exchanger, and each of the one or more fins is coupled to different
portions of the serpentine coil.
[0006] In yet another construction, the invention embodies a heat
exchanger including a coil that has bends and tube passes disposed
between the bends. The coil further has an inlet end and an outlet
end and being continuous between the inlet end and the outlet end.
The coil is defined by parallel microchannel passageways extending
from the inlet end to the outlet end. The heat exchanger also
includes a plurality of fins spaced apart from each other between a
first end of the heat exchanger and a second end of the heat
exchanger, and each of the plurality of fins is coupled to and
surrounds multiple tube passes of the coil.
[0007] Other aspects of the invention will become apparent by
consideration of the detailed description and accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a section view of a refrigerated merchandiser
including a heat exchanger embodying the present invention.
[0009] FIG. 2 is a perspective view of the heat exchanger of FIG. 1
from adjacent a first side and including fins and microchannel
coils circuits extending through the fins.
[0010] FIG. 3 is a perspective view of the heat exchanger of FIG. 1
from adjacent a second side opposite the first side.
[0011] FIG. 4 is a perspective view of an exemplary continuous
microchannel coil circuit of the heat exchanger of FIGS. 2 and
3.
[0012] FIG. 5 is a cross section of a portion of two adjacent
continuous microchannel coil circuits of FIG. 2 taken along line
5-5 in FIG. 2.
[0013] FIG. 6 is an end view of the heat exchanger of FIG. 2 from
adjacent the first end of the heat exchanger.
[0014] FIG. 7 is an end view of the heat exchanger of FIG. 2 from
adjacent the second end of the heat exchanger.
[0015] FIG. 8 is a cross section of the heat exchanger of FIG. 2
taken along line 8-8 in FIG. 2.
[0016] FIG. 9 is an enlarged view of a portion of the heat
exchanger of FIG. 8.
DETAILED DESCRIPTION
[0017] Before any embodiments of the invention are explained in
detail, it is to be understood that the invention is not limited in
its application to the details of construction and the arrangement
of components set forth in the following description or illustrated
in the following drawings. The invention is capable of other
embodiments and of being practiced or of being carried out in
various ways.
[0018] FIG. 1 illustrates an exemplary refrigerated merchandiser 10
that may be located in a supermarket or a convenience store or
other retail setting (not shown) for presenting fresh food,
beverages, and other product (not shown). As shown, the
merchandiser 10 is an upright merchandiser with an open front. The
merchandiser 10 can be an upright merchandiser that is provided
with or without doors, a horizontal merchandiser with an open or
enclosed top, or another type of merchandiser.
[0019] The refrigerated merchandiser 10 includes a case 100 that
has a base 104, a rear wall 108, and a canopy or case top 112. The
area that is partially enclosed by the base 104, the rear wall 108,
and the canopy 112 defines a product display area 116. As
illustrated, the product display area 116 is accessible by
customers through an opening 120 adjacent the front of the case
100. Shelves 124 are coupled to the rear wall 108 and extend
forward toward the opening 120 adjacent the front of the
merchandiser to support food product that is accessible by a
consumer through the opening 120.
[0020] The base 104 defines a lower portion of the product display
area 116 and can support food product. The base 104 further defines
a lower flue 134 and includes an inlet 138 located adjacent a lower
area of the opening 120. As illustrated, the lower flue 134 is in
fluid communication with the inlet 138 and directs an airflow 144,
which is generated by a fan 146 that is coupled to the case 100,
substantially horizontally through the base 104 from the inlet 138.
The inlet 138 is positioned to receive surrounding air in a
substantially vertical direction and directs the air into the lower
flue 134.
[0021] With continued reference to FIG. 1, the case 100 includes a
rear flue 148 extending upward from the base 104 and in fluid
communication with the lower flue 134. The rear flue 148 and the
lower flue 134 cooperatively define a corner 150 in the air
passageway. The rear flue 148 is defined by the rear wall 108 and
an intermediate wall 151 spaced apart from the rear wall 108, and
directs the airflow 144 generally vertically through the case 100.
In some constructions, the rear wall 108 can include apertures (not
shown) that fluidly couple the rear flue 148 with the product
display area 116 to permit at least some of the airflow 144 to
enter the product display area 116.
[0022] The canopy 112 defines an upper flue 156. The upper flue 156
is in fluid communication with the rear flue 148 and directs the
airflow 144 substantially horizontally through the canopy 112
toward an outlet 160. The lower flue 134, the rear flue 148, and
the upper flue 156 are fluidly coupled to each other to define an
air passageway that directs the airflow 144 from the inlet 138 to
the outlet 160.
[0023] The airflow that is discharged from the outlet 160 forms an
air curtain 174 that is directed generally downward across the
opening 120 to cool the food product within a desired or standard
temperature range (e.g., 32 to 41 degrees Fahrenheit). Generally,
the inlet 138 receives at least some air from the air curtain 174.
Although not shown, the case 100 can define a secondary air
passageway that directs a secondary air curtain (e.g., refrigerated
or non-refrigerated) from the canopy 112 generally downward across
the opening 120 to buffer the air curtain 174 to minimize
infiltration of ambient air into the product display area 116.
[0024] As illustrated in FIG. 1, the merchandiser also includes a
hybrid heat exchanger 190 that is positioned in a lower portion of
the rear flue 148. The illustrated heat exchanger 190 transfers
heat from the airflow 144 to refrigerant flowing through the heat
exchanger 190. As oriented, the airflow 144 passes substantially
vertically through the heat exchanger 190. Due to the positioning
of the heat exchanger 190 proximate the corner 150, the vertical
airflow 144 may not be identically uniform across a width W of the
heat exchanger 190 (see FIG. 1). In other constructions, the heat
exchanger 190 may be located anywhere within the lower flue 134,
the rear flue 148, or the upper flue 156. In further constructions,
the refrigerated merchandiser 10 may include more than one heat
exchanger 190 (e.g., positioned across a width of the case 100).
Although the invention is described with regard to the heat
exchanger 190 being positioned in and used in the context of a
refrigerated merchandiser, it will be understood that the invention
embodied herein and in the claims can be implemented in other
structures.
[0025] Referring to FIGS. 2, 3, and 6, the heat exchanger 190 is
divided along a width W into six zones 1, 2, 3, 4, 5, 6. Each zone
1-6 extends a length L of the heat exchanger 190 between a first
end 194 and a second end 200 of the heat exchanger 190 and
delineates an airflow section of the heat exchanger that receives a
portion of the airflow 144 through the heat exchanger 190. In other
constructions, the zones 1-6 may extend less than the length L of
the heat exchanger 190. In the exemplary heat exchanger 190 shown
in FIGS. 2-7, an inlet manifold 204 at the first end 194
distributes refrigerant to inlets of a series of six independent
coil or tube circuits 210A, 210B, 210C, 210D, 210E, 210F (referred
to interchangeably as coils or circuits 210A-F). As shown, the six
coil circuits 210A-F extend from the first end 194 to the second
end 200 of the heat exchanger 190 and pass through a plurality of
generally equally spaced and substantially parallel elongated fins
214 (additional interior fins, which may also vary in fin
density--that is, fins per inch--are not shown for clarity).
Furthermore, an outlet manifold 220 coupled to outlets of each coil
circuit 210A-F is adjacent the first end 194 and ultimately
collects refrigerant that has passed through the coil circuits
210A-F and directs the refrigerant for recirculation through the
refrigerant system (not shown).
[0026] Each coil circuit 210A-F includes a plurality of tube passes
225 (e.g., twelve tube passes 225 in each coil circuit 210A-F as
illustrated in FIG. 4) with the length of a single tube pass 225
extending the length L of the heat exchanger 190. In other
constructions, each coil circuit 210A-F may include more or fewer
than twelve tube passes 225. With reference to FIG. 3, no tube pass
225 crosses from one zone to another zone along the length of the
heat exchanger 190 or at the second end 200. That is, each tube
pass 225 extends from the first end 194 to the second end 200
within a single zone. As illustrated in FIG. 5, the longitudinal
extent of each tube pass 225 defines a tube plane 230 that is
oriented at an acute, non-zero angle 235 relative to a vertical
plane 240 (e.g., defined along an edge of a fin) and relative to a
horizontal plane 245 (e.g., defined along an edge of the fin that
is perpendicular to the other edge). In the illustrated
construction, the tube plane 230 is disposed at approximately 60
degrees relative to the horizontal plane 245. In other
constructions, the tube plane 230 may be vertical (parallel to the
plane 240), horizontal (parallel to the plane 245), or disposed at
any angle 235 between horizontal and vertical. In the illustrated
construction, each tube pass 225 in a single zone is oriented
parallel with each of the remaining tube passes 225 in that zone,
and the tube passes 225 in adjacent zones (e.g., zone 1 and zone 2,
zone 2 and zone 3, zone 3 and zone 4, zone 4 and zone 5, zone 5 and
zone 6, etc.) are oriented non-parallel with each other (best seen
in FIG. 9).
[0027] In some constructions, one or more tube passes 225 can be
oriented parallel to the vertical plane 240 or the horizontal plane
245 with one or more other tube passes 225 oriented at the non-zero
angle 235. When the tube plane 230 is vertical compared to being
horizontal, heat transfer between the airflow and the heat
exchanger 190 increases, but the velocity of the airflow traveling
through the heat exchanger 190 decreases (e.g., the static pressure
of the airflow increases). In contrast, when the tube plane 230 is
horizontal compared to being vertical, heat transfer between the
airflow and the heat exchanger 190 decreases, but the velocity of
the airflow traveling through the heat exchanger 190 increases
(e.g., the static pressure of the airflow decreases). Therefore,
when the tube plane 230 is disposed at an angle 235 between the
horizontal and vertical, an inverse relationship is observed
between the amount of heat transfer and the velocity of the airflow
traveling through the heat exchanger 190.
[0028] As best seen in FIGS. 2 and 3, adjacent tube passes 225 of
each coil circuit 210A-F are fluidly coupled together by a
crossover bend portion 250 at the first end 194 and are fluidly
coupled together by a return bend portion 255 at the second end
200. In the illustrated construction, each coil circuit 210A-F
includes five crossover bend portions 250 and six return bend
portions 255. In other constructions, the coil circuits 210A-F may
include more or fewer than the five crossover bend portions 250
and/or six return bend portions 255 based on the quantity of tube
passes 225.
[0029] With reference to FIGS. 3 and 7, the return bend portions
255 project from the last fin 214 at the second end 200 (i.e. the
second end fin 214). Each return bend portion 255 is located within
one of the zones 1-6 and seamlessly joins two adjacent tube passes
225 that extend through the length L of the heat exchanger 190
within the corresponding zone 1-6. As shown, the return bend
portions 255 maintain a parallel relationship between adjacent tube
passes 225 within the same coil circuit 210A-F (e.g., the tube
planes 230 of adjacent passes 220 are parallel). More specifically,
the return bend portions 255 located within the zones 1, 3, and 5
are twisted so that an inlet and an outlet of each return bend
portion 255 (in the direction of refrigerant flow) are parallel,
whereas the return bend portions 255 located within the zones 2, 4,
and 6 are generally only curved so that an inlet and an outlet of
each return bend portion 255 are parallel (FIG. 3).
[0030] With reference to FIGS. 2 and 4, the crossover bend portions
250 for each of the circuits 210A-F project from the last fin 214
at the front end 194. First crossover bend portions 250a join two
adjacent tube passes 225 to direct the circuits 210A-F from one
zone to an adjacent zone (e.g., from the first zone 1 to the second
zone 2). The illustrated first crossover bend portions 250a change
the orientation between adjacent tube passes 225 such that adjacent
tube passes 225 are obliquely oriented relative to each other
(e.g., the tube planes 230 of adjacent tube passes 225 are
obliquely oriented; FIG. 6). Second crossover bend portions 250b
also join two adjacent tube passes 225, but the second crossover
bend portions 250b direct the circuits 210A-F from one zone to a
nonadjacent zone (e.g., from the first zone 1 to the third zone 3).
As illustrated, the second crossover bend portions 250b maintain a
parallel relationship between adjacent tube passes 225 (e.g., the
tube planes 230 of adjacent passes 220 are parallel; FIG. 6).
[0031] As illustrated, each coil circuit 210A-F is formed from a
continuous microchannel tube that is bent into a serpentine shape
(e.g., the third coil circuit 210C is illustrated in FIG. 4 and is
representative of the serpentine shape of the coil circuits 210A,
210B, 210D-F). More specifically, and with reference to FIG. 5, the
microchannel tube defining each coil circuit 210A-F has internal
walls 260 that cooperate with each other and the exterior wall of
the tube to define a plurality of internal, parallel channels or
fluid passageways 265. The channels 265 of each coil circuit 210A-F
extend continuously along the entire length of each circuit 210A-F
between the inlet manifold 204 and the outlet manifold 220. As
shown in FIG. 5, a cross section of one tube pass 225 of each of
the second and third coil circuits 210B, 210C is illustrated and is
representative of the cross sections of each tube pass 225 of the
coil circuits 210A-F. In the illustrated construction, the tube
plane 230 defined by the second coil circuit 210B is oriented
non-parallel to the tube plane 230 defined by the third coil
circuit 210C, and each of the coil circuits 210B, 210C includes ten
channels 265A-J. In other constructions, each tube circuit 210A-F
may include more or fewer than ten channels 265. The illustrated
microchannel tube circuits 210A-F can be formed from any suitable
material (e.g., metal such as an aluminum alloy or copper). While
the microchannel tubes are illustrated with a substantially
rectangular cross-section, other tube shapes (e.g., circular, oval,
polygonal, and the like) are also possible and considered
herein.
[0032] As shown in FIGS. 8 and 9, each tube pass 225 of each of the
coil circuits 210A-F extends through a series of apertures 270
formed in the fins 214. That is, each tube pass extends through
each fin 214 once such that two or more of the tube passes extend
through the same fin 214. Stated another way, each of the fins 214
is coupled to different portions of each coil 210A-F. The apertures
270 in each fin 214 linearly align between the first and second
ends 194, 200 of the heat exchanger 190 along the length L to
accommodate the tube passes 225. The shape of the apertures 270
conforms to the shape of the tube passes 225 extending
therethrough, and each aperture 270 is oriented at the angle 235 to
accommodate the tube passes 225.
[0033] The heat exchanger 190 is assembled by inserting each tube
pass 225 within a corresponding series of apertures 270 of the fins
214. In an exemplary embodiment, the heat exchanger 190 can be
assembled in the same or a similar manner as described and
illustrated in U.S. patent application Ser. No. 13/768,238, filed
Feb. 15, 2013, (entitled "Multi-Zone Circuiting for a Plate-Fin and
Continuous Tube Heat Exchanger"), the entire contents of which are
incorporated herein by reference. For example, the tube passes 225
extend through each fin 214 so that the return bend portions 255
are coupled to two tube passes 225 adjacent the last fin 214 at the
second end 200, and the crossover bend portions 250a, 250b are
coupled to two tube passes 225 adjacent the fin 214 at the first
end 194 to construct each coil circuit 210A-210F. In particular and
with reference to FIGS. 3 and 6, each of the plurality of fins 214
is coupled to and surrounds multiple tube passes 225 of the coil
circuits 210A-F, and the bend portions 250 are coupled to the tube
passes 225 so that each coil circuit 210A-F passes through a
plurality of zones.
[0034] As illustrated, the first circuit 210A passes from the first
zone 1 to the second zone 2, from the second zone 2 to the third
zone 3, from the third zone 3 to the first zone 1, from the first
zone 1 to the second zone 2, and from the second zone 2 to the
third zone 3. The second circuit 210B passes from the second zone 2
to the third zone 3, from the third zone 3 to the first zone 1,
from the first zone 1 to the second zone 2, from the second zone 2
to the third zone 3, and from the third zone 3 to the first zone 1.
The third circuit 210C passes from the third zone 3 to the first
zone 1, from the first zone 1 to the second zone 2, from the second
zone 2 to the third zone 3, from the third zone 3 to the first zone
1, and from the first zone 1 to the second zone 2. The four circuit
210D passes from the fourth zone 4 to the fifth zone 5, from the
fifth zone 5 to the sixth zone 6, from the sixth zone 6 to the
fourth zone 4, from the fourth zone 4 to the fifth zone 5, and from
the fifth zone 5 to the sixth zone 6. The fifth circuit 210E passes
from the fifth zone 5 to the sixth zone 6, from the sixth zone 6 to
the fourth zone 4, from the fourth zone 4 to the fifth zone 5, from
the fifth zone 5 to the sixth zone 6, and from the sixth zone 6 to
the fourth zone 4. The sixth circuit 210F passes from the sixth
zone 6 to the fourth zone 4, from the fourth zone 4 to the fifth
zone 5, from the fifth zone 5 to the sixth zone 6, from the sixth
zone 6 to the fourth zone 4, and from the fourth zone 4 to the
fifth zone 5. In the illustrated construction, the connections
between the tube passes 225 and the bend portions 250, 250a, 250b
and the connections between the coil circuits 210A-F and the
manifolds 204, 245 are provided by a brazing operation.
[0035] Although the heat exchanger 190 includes six zones 1-6 and
six coil circuits 210A-F, heat exchangers with fewer or more than
six zones and six coil circuits are possible and considered herein.
Also, the horizontal and/or vertical spacing between the tubes of
each coil circuit or between the coil circuits can be modified as
desired. Other tube patterns also can be incorporated into the heat
exchanger (e.g., inline, staggered, angled, etc.).
[0036] In operation, refrigerant from the refrigerant system (not
shown) is directed from the inlet manifold 204 and is dispersed
through the coil circuits 210A-F such that refrigerant passes
within zones 1-6 toward the return bend portions 255 at the second
end 200. The return bend portions 255 route the refrigerant back
through the heat exchanger 190 toward the first end 194 so that
refrigerant is again routed back through the heat exchanger 190
within different zones 1-6 toward the second end 200 via the
crossover bends 270. The back and forth movement of the refrigerant
between the first and second ends 194, 200, as well as the
refrigerant passing through different zones 1-6 repeats until the
refrigerant reaches the outlet manifold 220. As the refrigerant
travels through the heat exchanger 190, heat is absorbed in the
coil circuits 210A-F via the airflow 144, and the vaporized
refrigerant is collected from each coil circuit 210A-F at the
outlet manifold 220 and thereafter dispersed back to the remainder
of the refrigerant system. The amount of time the refrigerant in
the circuits 210A-F spends in each zone (refrigerant passage time)
directly correlates with the amount of thermal balancing between
the circuits 210A-210F. Shifting individual coil circuits between
zones 1-6 balances the refrigerant superheat levels within each
circuit, maximizing the heat transfer rate from the air to the
refrigerant and more uniformly cooling the air across the entire
width of the heat exchanger 190. The microchannel design of the
coil circuits 210A-F also provides an increased cooling capacity of
the heat exchanger 190 compared to conventional heat exchangers
190. Due to the larger spacing between the microchannel circuits
210A-F achieved by the hybrid heat exchanger 190 when compared to
conventional microchannel heat exchangers, the heat exchanger 190
is less susceptible to ice formation in below freezing
applications.
[0037] Various features and advantages of the invention are set
forth in the following claims.
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