U.S. patent application number 13/472975 was filed with the patent office on 2012-11-22 for microchannel hybrid evaporator.
Invention is credited to Timothy D. Anderson.
Application Number | 20120291998 13/472975 |
Document ID | / |
Family ID | 47174059 |
Filed Date | 2012-11-22 |
United States Patent
Application |
20120291998 |
Kind Code |
A1 |
Anderson; Timothy D. |
November 22, 2012 |
MICROCHANNEL HYBRID EVAPORATOR
Abstract
A heat exchanger including a primary inlet manifold that has an
inlet port to receive refrigerant from a source, a primary outlet
manifold that has an outlet port to discharge refrigerant from the
heat exchanger, and a plurality of microchannel tubes fluidly
connected between the primary inlet manifold and the primary outlet
manifold and spaced apart from each other. Each of the plurality of
microchannel tubes has a secondary inlet manifold fluidly coupled
to the primary inlet manifold, a secondary outlet manifold fluidly
coupled to the primary outlet manifold, and at least one
microchannel fluidly coupled between the secondary inlet manifold
and the secondary outlet manifold to direct refrigerant to the
secondary outlet manifold. The heat exchanger also includes a
plurality of fins disposed between adjacent microchannel tubes and
oriented to define an airflow path along the longitudinal direction
of the microchannel tubes.
Inventors: |
Anderson; Timothy D.; (St.
Louis, MO) |
Family ID: |
47174059 |
Appl. No.: |
13/472975 |
Filed: |
May 16, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61486521 |
May 16, 2011 |
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Current U.S.
Class: |
165/104.14 |
Current CPC
Class: |
F28F 1/14 20130101; F28F
2215/00 20130101; F28F 9/0243 20130101; F28F 2009/0297 20130101;
F28F 2260/02 20130101; F28F 2215/04 20130101; F28D 1/05383
20130101; F28F 9/027 20130101; F28D 2021/0071 20130101 |
Class at
Publication: |
165/104.14 |
International
Class: |
F28D 15/00 20060101
F28D015/00 |
Claims
1. A heat exchanger comprising: a primary inlet manifold including
an inlet port to receive refrigerant from a source; a primary
outlet manifold including an outlet port to discharge refrigerant
from the primary outlet manifold; a plurality of microchannel tubes
fluidly connected between the primary inlet manifold and the
primary outlet manifold and spaced apart from each other, each of
the plurality of microchannel tubes including a secondary inlet
manifold fluidly coupled to the primary inlet manifold, a secondary
outlet manifold fluidly coupled to the primary outlet manifold, and
at least one microchannel fluidly coupled between the secondary
inlet manifold and the secondary outlet manifold to direct
refrigerant to the secondary outlet manifold; and a plurality of
fins disposed between adjacent microchannel tubes and oriented to
define an airflow path along the longitudinal direction of the
microchannel tubes.
2. The heat exchanger of claim 1, wherein the plurality of
microchannel tubes are spaced apart from each other along the
length of the primary inlet manifold.
3. The heat exchanger of claim 1, wherein the microchannel tubes
extend substantially vertically and the fins are oriented such that
an airflow is directed in a generally vertical direction along the
airflow path.
4. The heat exchanger of claim 1, wherein the fins have one of a
rectangular cross-sectional shape, a triangular cross-sectional
shape, a curved cross-sectional shape.
5. The heat exchanger of claim 4, wherein the fins define a fin
density that varies along the length of each of the microchannel
tubes.
6. The heat exchanger of claim 1, wherein the fins have one of a
wavy profile, a louvered profile, and a perforated profile.
7. The heat exchanger of claim 1, wherein the primary inlet
manifold and the primary outlet manifold are oriented substantially
horizontal, and wherein the secondary inlet manifold is oriented at
a non-zero angle relative to the primary inlet manifold and the
secondary outlet manifold is oriented at a non-zero angle relative
to the primary outlet manifold.
8. A heat exchanger comprising: an inlet manifold including an
inlet port to receive refrigerant from a source; an outlet manifold
including an outlet port to discharge refrigerant from the primary
outlet manifold; a plurality of refrigerant tubes fluidly connected
between the inlet manifold and the outlet manifold and spaced apart
from each other, each of the plurality of microchannel tubes
including a plurality of micro channels; and a plurality of fins
positioned between adjacent microchannel tubes and having an
airflow inlet oriented to receive an airflow and an airflow outlet,
the fins defining a fin density that varies along the length of the
refrigerant tubes based on the location of the fins relative to the
airflow inlet and the airflow outlet.
9. The heat exchanger of claim 8, wherein the fin density of the
fins located adjacent the airflow inlet is lower than the fin
density of the fins located adjacent the airflow outlet.
10. The heat exchanger of claim 9, wherein the fins define a first
fin portion having a first fin density and a second fin portion
having a second fin density that is lower than the first fin
density.
11. The heat exchanger of claim 10, wherein the fins further define
a third fin portion having a third fin density that is lower than
the second fin density.
12. The heat exchanger of claim 8, wherein the fins are oriented to
define an airflow path along the longitudinal direction of the
microchannel tubes.
13. The heat exchanger of claim 12, wherein the refrigerant tubes
extend substantially vertically and the fins are oriented such that
an airflow is directed in a generally vertical direction along the
airflow path.
14. The heat exchanger of claim 8, wherein the fins have one of a
rectangular cross-sectional shape, a triangular cross-sectional
shape, a curved cross-sectional shape, a wavy profile, a louvered
profile, and a perforated profile.
15. The heat exchanger of claim 8, wherein the fins are defined by
a body portion and end portions on both ends, at least one of the
end portions defining one of the airflow inlet and the airflow
outlet on a face side of the heat exchanger.
16. The heat exchanger of claim 15, wherein the fins include curved
end portions on both ends such that the airflow inlet and the
airflow outlet are disposed in at least one face side of the heat
exchanger.
17. The heat exchanger of claim 16, wherein each of the body
portion and the curved end portions are defined by a substantially
rectangular cross-section.
18. The heat exchanger of claim 15, wherein the airflow inlet and
the airflow outlet are disposed on the same face side of the heat
exchanger.
19. The heat exchanger of claim 18, wherein the airflow inlet and
the airflow outlet are defined by a substantially rectangular
cross-section.
20. A heat exchanger comprising: a primary inlet manifold including
an inlet port to receive refrigerant from a source; a primary
outlet manifold including an outlet port to discharge refrigerant
from the primary outlet manifold; a plurality of microchannel tubes
fluidly connected between the primary inlet manifold and the
primary outlet manifold and spaced apart from each other, each of
the plurality of microchannel tubes including a secondary inlet
manifold fluidly coupled to the primary inlet manifold, a secondary
outlet manifold fluidly coupled to the primary outlet manifold, and
a plurality of microchannels fluidly coupled between the secondary
inlet manifold and the secondary outlet manifold to direct
refrigerant to the secondary outlet manifold; and a plurality of
fins disposed between adjacent microchannel tubes and having an
airflow inlet oriented to receive an airflow and an airflow outlet,
the fins defining a first fin portion having a first fin density
and a second fin portion having a second fin density such that the
density of the fins varies along the length of the refrigerant
tubes based on the location of the fins relative to the airflow
inlet and the airflow outlet.
21. The heat exchanger of claim 20, wherein the first fin portion
is disposed adjacent the secondary outlet manifold and the first
fin density is higher than the second fin density.
22. The heat exchanger of claim 21, wherein the fins further define
a third fin portion disposed adjacent the secondary inlet manifold
and has a third fin density that is lower than the second fin
density.
23. The heat exchanger of claim 20, wherein the fins are oriented
to define an airflow path along the longitudinal direction of the
microchannel tubes.
Description
RELATED APPLICATIONS
[0001] This patent application claims priority to U.S. Provisional
Patent Application Ser. No. 61/486,521 filed May 16, 2011, the
entire contents of which are hereby incorporated by reference.
BACKGROUND
[0002] The present invention relates to an evaporator, and more
particularly to a microchannel evaporator.
[0003] In conventional practice, many refrigeration circuits
utilize an evaporator including a coil that is formed from round
copper or aluminum tubing. Other refrigeration circuits utilize an
evaporator that includes a coil with microchannel tubes and fins in
very high densities that can only operate at refrigerant
temperatures above 32 degrees Fahrenheit due to rapid ice buildup
in the fins at temperatures below 32 degrees Fahrenheit.
SUMMARY
[0004] The invention provides a heat exchanger that includes
microchannel tubes and fins for use in low (e.g., -20 degrees
Fahrenheit) and medium-temperature (e.g., 26 degrees Fahrenheit)
refrigeration applications. The evaporator can achieve a discharge
air temperature that is as close as possible to the temperature of
the refrigerant inside the coil, which allows for higher
refrigerant temperatures in the coil to be used, which saves
energy. The evaporator can reduce the refrigerant charge of the
system by using microchannel ports inside of the coil rather than
traditional round copper or aluminum tubes. The evaporator can be
modular or full length such that it is the same nominal length as a
merchandiser. The evaporator can vary in depth, height, and width.
Refrigerant may enter and exit on the same side of the coil, on
opposite sides of the coil, or somewhere in between the ends of the
larger manifolds. Sandwiched between the microchannel tubes are
fins which can vary in density from one to ten fins per inch
depending upon the temperature application. The fins can have a
variety of shapes (e.g., triangular, offset strips, wavy, louvered,
perforated, etc.). Fin density in the evaporator can be the same or
varied in different areas of the evaporator. Fin density can be
varied along the coil such that a lower fin density can be used at
the air inlet side of the coil to remove moisture from an air flow.
As more moisture is removed from the air passing through the coil,
higher fin densities can be used, especially near the outlet. For
low temperature applications fin density can be decreased as needed
to accommodate buildup of frost.
[0005] In one construction, the invention provides a heat exchanger
including a primary inlet manifold that has an inlet port to
receive refrigerant from a source, a primary outlet manifold that
has an outlet port to discharge refrigerant from the heat
exchanger, and a plurality of microchannel tubes fluidly connected
between the primary inlet manifold and the primary outlet manifold
and spaced apart from each other. Each of the plurality of
microchannel tubes has a secondary inlet manifold fluidly coupled
to the primary inlet manifold, a secondary outlet manifold fluidly
coupled to the primary outlet manifold, and at least one
microchannel fluidly coupled between the secondary inlet manifold
and the secondary outlet manifold to direct refrigerant to the
secondary outlet manifold. The heat exchanger also includes a
plurality of fins disposed between adjacent microchannel tubes and
oriented to define an airflow path along the longitudinal direction
of the microchannel tubes.
[0006] In another construction, the invention provides a heat
exchanger including an inlet manifold that has an inlet port to
receive refrigerant from a source, an outlet manifold that has an
outlet port to discharge refrigerant from the heat exchanger, and a
plurality of refrigerant tubes fluidly connected between the inlet
manifold and the outlet manifold and spaced apart from each other.
Each of the plurality of microchannel tubes has a plurality of
microchannels. The heat exchanger also includes a plurality of fins
positioned between adjacent microchannel tubes and having an
airflow inlet oriented to receive an airflow and an airflow outlet,
the fins defining a fin density that varies along the length of the
refrigerant tubes based on the location of the fins relative to the
airflow inlet and the airflow outlet.
[0007] In another construction, the invention provides a heat
exchanger including a primary inlet manifold that has an inlet port
to receive refrigerant from a source, a primary outlet manifold
that has an outlet port to discharge refrigerant from the heat
exchanger, and a plurality of microchannel tubes fluidly connected
between the primary inlet manifold and the primary outlet manifold
and spaced apart from each other. Each of the plurality of
microchannel tubes has a secondary inlet manifold fluidly coupled
to the primary inlet manifold, a secondary outlet manifold fluidly
coupled to the primary outlet manifold, and a plurality of
microchannels fluidly coupled between the secondary inlet manifold
and the secondary outlet manifold to direct refrigerant to the
secondary outlet manifold. The heat exchanger also includes a
plurality of fins disposed between adjacent microchannel tubes. The
fins have an airflow inlet oriented to receive an airflow and an
airflow outlet, and define a first fin portion that has a first fin
density and a second fin portion that has a second fin density such
that the density of the fins varies along the length of the
refrigerant tubes based on the location of the fins relative to the
airflow inlet and the airflow outlet.
[0008] Other aspects of the invention will become apparent by
consideration of the detailed description and accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a perspective view of an evaporator embodying the
invention.
[0010] FIG. 2 is another perspective view of the evaporator of FIG.
1.
[0011] FIG. 3 is an enlarged view of a portion of the evaporator of
FIG. 2.
[0012] FIG. 4 is a perspective view exposing a portion of the
evaporator.
[0013] FIG. 5 is a cross-section view of a portion of the
evaporator taken along line 5-5 of FIG. 2.
[0014] FIG. 6 is a perspective view of another evaporator embodying
the invention.
[0015] FIG. 7 is a perspective view of a portion of the evaporator
of FIG. 6.
[0016] FIG. 8 is a perspective view of another portion of the
evaporator of FIG. 6.
[0017] FIG. 9 is a side view of the portion of the evaporator of
FIG. 8.
[0018] FIG. 10 is a cross-section view of a portion of another
evaporator embodying the invention.
[0019] 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.
DETAILED DESCRIPTION
[0020] FIGS. 1 and 2 illustrate an evaporator 10 that can be used
as part of a refrigeration system (not shown) in low-temperature
refrigeration applications (e.g., -20 degrees Fahrenheit) and
medium-temperature refrigeration applications (e.g., 26 degrees
Fahrenheit) in a retail setting (e.g., grocery stores or
supermarkets) to provide heat transfer from the refrigerant in the
evaporator 10 to air flowing through the evaporator 10. The
evaporator 10 can be used in conjunction with refrigerated
merchandisers, walk-in coolers, walk-in freezers, or other cold
storage spaces.
[0021] As shown in FIGS. 1-4, the evaporator 10 includes a primary
inlet manifold 15 that has an inlet port 20 for receiving
refrigerant, and a primary outlet manifold 25 that has an outlet
port 30 for discharging refrigerant from the evaporator 10.
Refrigerant can enter and exit on the same side of the evaporator
10, on opposite sides of the evaporator 10, or somewhere between
the ends of the manifolds 15, 25. The evaporator 10 also includes a
plurality of secondary inlet manifolds 35 that are fluidly coupled
to the primary inlet manifold 15, a plurality of secondary outlet
manifolds 40 that are fluidly coupled to the primary outlet
manifold 25, and flat tubes 45 that are fluidly coupled between the
secondary inlet manifolds 35 and the secondary outlet manifolds 40.
The secondary inlet manifolds 35 are spaced apart from each other
along the length of the primary inlet manifold 15, and the
secondary outlet manifolds are spaced apart from each other along
the length of the primary outlet manifold 25.
[0022] The flat tubes 45 can be spaced at different or varying
distances relative to each other to maximize performance of the
evaporator 10 at low and medium temperatures. As illustrated in
FIG. 5, the flat tubes 45 include multiple internal passageways or
microchannels 50. Generally, the microchannels 50 are much smaller
in size than the internal passageway of a conventional fin-and-tube
evaporator coil. The microchannels 50 can be defined by any
suitable cross-section (e.g., rectangular, triangular, circular,
oval, etc.) for distributing refrigerant.
[0023] As illustrated in FIG. 3, the evaporator 10 includes a
plurality of fins 55 that are coupled between adjacent flat tubes
45. As illustrated, the fins 55 are oriented within the evaporator
10 to define an airflow path that receives an airflow 60 in a
generally downward direction along the length of the flat tubes 45
(i.e., along the longitudinal direction of the tubes 45). In other
constructions, the fins 55 can receive air from any suitable
direction. The fins 55 can have any suitable cross-sectional shape
(e.g., rectangular, oval, circular, triangular, offset strips,
wavy, louvered, perforated, etc.).
[0024] The fins 55 vary in density along the length of the flat
tube 45. With reference to FIG. 4, the evaporator 10 is defined by
a first density fin portion 65 located adjacent the secondary
outlet manifolds 40, a second density fin portion 70 at a central
area of the flat tubes 45, and a third density fin portion 75
located adjacent the secondary inlet manifolds 35. The second
density fin portion 70 is less dense than the first density fin
portion 65, and the third density fin portion 75 is less dense than
the second fin density portion 65. For example, the fins 55 can
vary in density from one to ten fins per inch between the first
density fin portion 65, the second density fin portion 70, and the
third density fin portion 75 depending on the temperature
application. In the illustrated construction, the first, second,
and third fin density portions 65, 70, 75 do not overlap. In other
constructions, the first, second, and third fin density portions
65, 70, 75 may overlap. Generally, the fins 55 can have any shape
suitable for heat transfer.
[0025] FIGS. 6-9 illustrate another evaporator 110 for use in a
refrigeration system. Except as described below, the evaporator 110
is the same as the evaporator 10 described with regard to FIGS.
1-5, and like elements have been given the same reference
numerals.
[0026] With reference to FIG. 6, the evaporator 110 includes a
single inlet manifold 115 and a single outlet manifold 120. The
inlet manifold 115 and the outlet manifold 120 are fluidly coupled
via flat tubes 125. As illustrated in FIG. 6, a plurality of fins
130 are coupled between adjacent flat tubes 125. With reference to
FIGS. 7-9, the fins 130 include a rectangular-shaped body portion
135 and a curved end portion 140, on each end. As illustrated in
FIGS. 8 and 9, the fins 130 are positioned to receive an airflow
145. In other constructions, the fins 130 may be other shapes and
receive air in other directions.
[0027] FIG. 10 illustrates another evaporator 210. Except as
described below, the evaporator 210 is the same as the evaporator
10 described with regard to FIGS. 1-5. In particular, the
illustrated evaporator 210 includes a plurality of microchannels
215 (one shown). As illustrated, the microchannel 215 has a large
or over-sized cavity 220 to accommodate liquid cooling fluids
(e.g., 35 percent propylene glycol).
[0028] In operation, the evaporator 10, 110, 210 functions as part
of a two-phase refrigeration system in which the evaporator 10,
110, 210 receives low-pressure, low-temperature liquid refrigerant,
removes heat from an airflow (e.g., airflow 60, 145) that passes
through the evaporator 10, 110, 210, and discharges gaseous
refrigerant to one or more compressors (not shown). The
low-pressure, low-temperature liquid refrigerant evaporates as it
passes through the evaporator 10, 110, 210 such that the
refrigerant passes through a substantial portion of the evaporator
10, 110, 210 as a two-phase mixture (i.e., a liquid-gas state).
[0029] With reference to the evaporator 10, for example, the inlet
port 20 directs low-pressure, low-temperature liquid refrigerant
into the primary inlet manifold 15, which provides refrigerant to
the plurality of second inlet manifolds 35. The second inlet
manifolds 35 direct refrigerant to the plurality of flat tubes 45
where the refrigerant is then directed through the microchannels
50. The refrigerant flows from the microchannels 50 to the
plurality of secondary outlet manifolds 40, and then to the primary
outlet manifold 25 before reaching the outlet port 30.
[0030] The evaporator 10, 110, 210 achieves a discharge air
temperature that is as close as possible to the temperature of the
refrigerant inside the coil. The similarity in temperatures between
the refrigerant and the air flowing through the evaporator 10, 110,
210 results in higher refrigerant temperatures in the coil, which
reduces energy costs because it is more likely that the refrigerant
directed to the compressors will be in a gaseous state. The
microchannels 50, 215 minimize the refrigerant charge of the
refrigeration system as compared to conventional evaporators with
round copper or aluminum tubes. The evaporator 10, 110, 210 can be
modular or full length, and the size (e.g., depth, height, or
width) can vary depending on the size and type of merchandiser in
which the evaporator 10, 110, 210 will be used.
[0031] The evaporator 10, 110, 210 accommodates multiple or
variable fin densities and microchannel tube spacing to maximize
performance of the evaporator 10, 110, 210 based on the temperature
application in which the evaporator 10, 110, 210 will be used. For
example, the fin density can be varied in the evaporator 10, 110,
210 so that a low fin density (e.g., third density fin portion 75)
is oriented at the air inlet side of the evaporator 10, 110, 210 to
remove moisture from an air flow to minimize frosting of the
evaporator 10, 110, 210. As moisture is removed from the air
passing through the evaporator 10, 110, 210, higher fin densities
(e.g., first density fin portion 65, second density fin portion 70)
can be oriented adjacent the middle and outlet-side of the
evaporator 10, 110, 210. In low temperature applications, the fin
density of the evaporator 10, 110, 210 can be further decreased
relative to medium temperature applications to minimize frost
buildup.
[0032] The primary inlet manifold 15, 115 distributes refrigerant
to the microchannels 50, 215 so that the latent heat absorbed by
the refrigerant is as high as possible without frosting the
evaporator 10, 110, 210. With regard to the evaporator 10, for
example, the plurality of secondary inlet manifolds 35 evenly
distribute refrigerant from primary inlet manifold 15 to the
microchannels 50. Similarly, the plurality of secondary outlet
manifolds evenly distribute heated refrigerant from the
microchannels 50 to the primary outlet manifold 35.
[0033] Various features and advantages of the invention are set
forth in the following claims.
* * * * *