U.S. patent application number 15/002445 was filed with the patent office on 2017-07-27 for sealed system and a method for defrosting an evaporator.
The applicant listed for this patent is General Electric Company. Invention is credited to Carlos A. Herrera, Eric Gregory Tauzer, Kristin Marie Weirich.
Application Number | 20170211871 15/002445 |
Document ID | / |
Family ID | 59359476 |
Filed Date | 2017-07-27 |
United States Patent
Application |
20170211871 |
Kind Code |
A1 |
Herrera; Carlos A. ; et
al. |
July 27, 2017 |
Sealed System and a Method For Defrosting an Evaporator
Abstract
The present subject matter provides a sealed system for an
appliance. The sealed system includes a compressor operable to
generate a flow of compressed refrigerant, an evaporator and a
drain trough disposed below the evaporator. A bypass conduit
fluidly couples a bypass valve and the evaporator. The bypass valve
is configured for selectively directing refrigerant from a
condenser around an expansion device to the evaporator. A portion
of the bypass conduit is positioned at and connected to the drain
trough. A related method for defrosting an evaporator is also
provided.
Inventors: |
Herrera; Carlos A.;
(Fisherville, KY) ; Weirich; Kristin Marie;
(Louisville, KY) ; Tauzer; Eric Gregory;
(Louisville, KY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
59359476 |
Appl. No.: |
15/002445 |
Filed: |
January 21, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25D 2500/02 20130101;
F25B 2400/052 20130101; F25B 2400/12 20130101; F25B 2400/0411
20130101; F25D 21/006 20130101; F25B 2400/01 20130101; F25B
2400/054 20130101; F25D 21/14 20130101; F25D 21/12 20130101; F25B
47/02 20130101 |
International
Class: |
F25D 21/12 20060101
F25D021/12; F25D 21/00 20060101 F25D021/00; F25B 39/00 20060101
F25B039/00 |
Claims
1. A sealed system for an appliance, comprising: a compressor
operable to generate a flow of compressed refrigerant; a condenser
disposed downstream of the compressor such that the condenser
receives the flow of compressed refrigerant from the compressor
during operation of the compressor; a fan positioned proximate the
condenser and operable to generate a flow of air across the
condenser; an expansion device; an evaporator; a drain trough
disposed below the evaporator; a bypass valve disposed downstream
of the condenser; and a bypass conduit fluidly coupling the bypass
valve and the evaporator, the bypass valve configured for
selectively directing refrigerant from the condenser around the
expansion device to the evaporator via the bypass conduit, a
portion of the bypass conduit positioned at and connected to the
drain trough.
2. The sealed system of claim 1, wherein the drain trough defines a
length, the bypass conduit contacting the drain trough along the
length of the drain trough.
3. The sealed system of claim 1, wherein the bypass conduit defines
a constant internal diameter.
4. The sealed system of claim 1, wherein the fan is configured to
deactivate whenever the bypass valve directs refrigerant from the
condenser around the expansion device to the evaporator.
5. The sealed system of claim 1, wherein the sealed system is
charged with a flammable refrigerant.
6. The sealed system of claim 5, wherein the flammable refrigerant
comprises a flammable alkane, hydrocarbon or organic compound.
7. The sealed system of claim 1, further comprising an electric
heating element mounted to the bypass conduit.
8. The sealed system of claim 7, wherein the electric heating
element is encased within foam insulation.
9. The sealed system of claim 1, wherein the sealed system does not
include an electric heating element disposed at an outer surface of
the evaporator.
10. A method for defrosting an evaporator within an appliance,
comprising: running a compressor of the appliance during a
condenser preheat, a condenser fan of the appliance being
deactivated during the condenser preheat such that a temperature of
a condenser of the appliance increases while the compressor is
running during the condenser preheat; actuating a bypass valve of
the appliance such that refrigerant from the condenser bypasses an
expansion device of the appliance and flows to the evaporator; and
running the compressor during an evaporator defrost, the
temperature of the condenser decreasing while the compressor is
running during the evaporator defrost.
11. The method of claim 10, wherein the condenser fan is
deactivated during the evaporator defrost.
12. The method of claim 10, wherein a bypass conduit fluidly
coupling the bypass valve and the evaporator is connected to a
drain trough disposed below the evaporator.
13. The method of claim 12, wherein a portion of the bypass conduit
extends along a length of the drain trough.
14. The method of claim 12, further comprising operating an
electric heating element mounted to the bypass conduit during the
evaporator defrost.
15. The method of claim 14, wherein the electric heating element is
encased within foam insulation.
16. The method of claim 10, wherein the refrigerant is a flammable
refrigerant.
17. The method of claim 16, wherein the flammable refrigerant
comprises a flammable alkane, hydrocarbon or organic compound.
Description
FIELD OF THE INVENTION
[0001] The present subject matter relates generally to sealed
systems for appliances, such as refrigerator appliances, and
methods for defrosting evaporators of sealed systems.
BACKGROUND OF THE INVENTION
[0002] Refrigerators generally include a cabinet that defines a
chilled chamber. The chilled chamber is commonly cooled with a
sealed system having an evaporator. One problem frequently
encountered with modern refrigerators is inefficient defrosting of
the evaporator. For example, when the evaporator is active, frost
can accumulate on the evaporator and thereby reduce efficiency of
the evaporator. One effort to reduce or eliminate frost from the
evaporator has been to utilize a heater to heat the evaporator when
the evaporator is not operating.
[0003] Suitably defrosting the evaporator with the heater is
difficult. For example, heaters can be large energy consumers and
can negatively affect the energy efficiency of the refrigerator
during long defrosts. In addition, the heater can raise the
temperate of the adjacent chilled chamber during long defrosts, and
high chilled chamber temperatures can lead to freezer burn and
other negative effects. Radiant heaters can also be unsuitable for
sealed systems charged with organic, flammable refrigerants due to
temperature exposure requirements for such sealed systems. The
temperature limits imposed on sealed systems charged with flammable
refrigerant can make defrosting an evaporator with a radiant heater
impractical.
[0004] Accordingly, a sealed system with features for effectively
and efficiently defrosting an evaporator would be useful. In
addition, a method for effectively and efficiently defrosting an
evaporator would be useful.
BRIEF DESCRIPTION OF THE INVENTION
[0005] The present subject matter provides a sealed system for an
appliance. The sealed system includes a compressor operable to
generate a flow of compressed refrigerant, an evaporator and a
drain trough disposed below the evaporator. A bypass conduit
fluidly couples a bypass valve and the evaporator. The bypass valve
is configured for selectively directing refrigerant from a
condenser around an expansion device to the evaporator via the
bypass conduit. A portion of the bypass conduit is positioned at
and connected to the drain trough. A related method for defrosting
an evaporator is also provided. Additional aspects and advantages
of the invention will be set forth in part in the following
description, or may be apparent from the description, or may be
learned through practice of the invention.
[0006] In a first exemplary embodiment, a sealed system for an
appliance is provided. The sealed system includes a compressor
operable to generate a flow of compressed refrigerant. A condenser
is disposed downstream of the compressor such that the condenser
receives the flow of compressed refrigerant from the compressor
during operation of the compressor. A fan is positioned proximate
the condenser and operable to generate a flow of air across the
condenser. The sealed system also includes an expansion device and
an evaporator. A drain trough is disposed below the evaporator. A
bypass valve is disposed downstream of the condenser. A bypass
conduit fluidly couples the bypass valve and the evaporator. The
bypass valve is configured for selectively directing refrigerant
from the condenser around the expansion device to the evaporator. A
portion of the bypass conduit is positioned at and connected to the
drain trough.
[0007] In a second exemplary embodiment, a method for defrosting an
evaporator within an appliance is provided. The method includes
running a compressor of the appliance during a condenser preheat. A
condenser fan of the appliance is deactivated during the condenser
preheat such that a temperature of a condenser of the appliance
increases while the compressor is running during the condenser
preheat. The method also includes actuating a bypass valve of the
appliance such that refrigerant from the condenser bypasses an
expansion device of the appliance and flows to the evaporator and
running the compressor during an evaporator defrost. The
temperature of the condenser decreases while the compressor is
running during the evaporator defrost.
[0008] These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following description and appended claims. The accompanying
drawings, which are incorporated in and constitute a part of this
specification, illustrate embodiments of the invention and,
together with the description, serve to explain the principles of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] A full and enabling disclosure of the present invention,
including the best mode thereof, directed to one of ordinary skill
in the art, is set forth in the specification, which makes
reference to the appended figures.
[0010] FIG. 1 is a front elevation view of a refrigerator appliance
according to an exemplary embodiment of the present subject
matter.
[0011] FIG. 2 is schematic view of certain components of the
exemplary refrigerator appliance of FIG. 1.
[0012] FIG. 3 provides a schematic view of various components of a
refrigeration system of the exemplary refrigerator appliance of
FIG. 1.
[0013] FIG. 4 provides a schematic view of an evaporator and a
bypass conduit the exemplary refrigeration system of FIG. 3.
DETAILED DESCRIPTION
[0014] Reference now will be made in detail to embodiments of the
invention, one or more examples of which are illustrated in the
drawings. Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing
from the scope or spirit of the invention. For instance, features
illustrated or described as part of one embodiment can be used with
another embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
[0015] FIG. 1 depicts a refrigerator appliance 10 that incorporates
a sealed refrigeration system 60 (FIG. 2). It should be appreciated
that the term "refrigerator appliance" is used in a generic sense
herein to encompass any manner of refrigeration appliance, such as
a freezer, refrigerator/freezer combination, and any style or model
of conventional refrigerator. In addition, it should be understood
that the present subject matter is not limited to use in
appliances. Thus, the present subject matter may be used for any
other suitable purpose, such as in HVAC units.
[0016] In the exemplary embodiment shown in FIG. 1, the
refrigerator appliance 10 is depicted as an upright refrigerator
having a cabinet or casing 12 that defines a number of internal
chilled storage compartments. In particular, refrigerator appliance
10 includes upper fresh-food compartments 14 having doors 16 and
lower freezer compartment 18 having upper drawer 20 and lower
drawer 22. The drawers 20 and 22 are "pull-out" drawers in that
they can be manually moved into and out of the freezer compartment
18 on suitable slide mechanisms.
[0017] FIG. 2 is a schematic view of certain components of
refrigerator appliance 10, including a sealed refrigeration system
60 of refrigerator appliance 10. A machinery compartment 62
contains components for executing a known vapor compression cycle
for cooling air. The components include a compressor 64, a
condenser 66, an expansion device 68, and an evaporator 70
connected in series and charged with a refrigerant. As will be
understood by those skilled in the art, refrigeration system 60 may
include additional components, e.g., at least one additional
evaporator, compressor, expansion device, and/or condenser. As an
example, refrigeration system 60 may include two evaporators.
[0018] Within refrigeration system 60, refrigerant flows into
compressor 64, which operates to increase the pressure of the
refrigerant. This compression of the refrigerant raises its
temperature, which is lowered by passing the refrigerant through
condenser 66. Within condenser 66, heat exchange with ambient air
takes place so as to cool the refrigerant. A condenser fan 72 is
used to pull air across condenser 66, as illustrated by arrows
A.sub.C, so as to provide forced convection for a more rapid and
efficient heat exchange between the refrigerant within condenser 66
and the ambient air. Thus, as will be understood by those skilled
in the art, increasing air flow across condenser 66 can, e.g.,
increase the efficiency of condenser 66 by improving cooling of the
refrigerant contained therein.
[0019] An expansion device (e.g., a valve, capillary tube, or other
restriction device) 68 receives refrigerant from condenser 66. From
expansion device 68, the refrigerant enters evaporator 70. Upon
exiting expansion device 68 and entering evaporator 70, the
refrigerant drops in pressure. Due to the pressure drop and/or
phase change of the refrigerant, evaporator 70 is cool relative to
compartments 14 and 18 of refrigerator appliance 10. As such,
cooled air is produced and refrigerates compartments 14 and 18 of
refrigerator appliance 10. Thus, evaporator 70 is a type of heat
exchanger which transfers heat from air passing over evaporator 70
to refrigerant flowing through evaporator 70. An evaporator fan 74
is used to pull air across evaporator 70 and circulated air within
compartments 14 and 18 of refrigerator appliance 10.
[0020] Collectively, the vapor compression cycle components in a
refrigeration circuit, associated fans, and associated compartments
are sometimes referred to as a sealed refrigeration system operable
to force cold air through compartments 14, 18 (FIG. 1). The
refrigeration system 60 depicted in FIG. 2 is provided by way of
example only. Thus, it is within the scope of the present subject
matter for other configurations of the refrigeration system to be
used as well.
[0021] FIG. 3 provides a schematic view of various components of
refrigeration system 60. As described above, refrigeration system
60 is operable to cool compartments 14 and 18 of refrigerator
appliance 10. In such a manner, refrigeration system 60 assists
with increasing a storage or shelf life of food items within
compartments 14 and 18 of refrigerator appliance 10. Refrigeration
system 60 may also include a filter/drier 84 to condition
refrigerant within refrigeration system 60. In addition, expansion
device 68 is shown as a capillary tube in FIG. 3. A suction line 86
of refrigeration system 60 extends between evaporator 70 and
compressor 64 and directs refrigerant from evaporator 70 to
compressor 64 during operation of compressor 64. Suction line 86 is
coupled to the capillary tube in order to provide heat transfer
between refrigerant entering evaporator 70 from the capillary tube
and refrigerant returning to compressor 64 from evaporator 70 via
suction line 86.
[0022] During operation of refrigeration system 60, water vapor in
compartments 14 and 18 of refrigerator appliance 10 may condense
onto evaporator 70 and form frost buildup on evaporator 70.
Overtime, frost accumulation on evaporator 70 can negatively affect
performance of evaporator 70. Thus, refrigeration system 60
includes features for defrosting evaporator 70. In particular,
refrigeration system 60 includes features for fully and/or
efficiently defrosting evaporator 70 relative to known systems that
expose evaporators to radiant heating elements during defrosts.
Such features of refrigeration system 60 are discussed in greater
detail below in the context of FIG. 3.
[0023] As shown in FIG. 3 and as discussed above, refrigeration
system 60 includes compressor 64, condenser 66, expansion device 68
and evaporator 70 that are connected to each other in a loop in
order to execute a known vapor compression cycle for cooling air.
Refrigeration system 60 also includes a bypass valve 80 and a
bypass conduit 82 that interrupt the normal refrigerant operating
loop of refrigeration system 60 during a defrosting operation of
refrigeration system 60.
[0024] Bypass valve 80 is disposed downstream of condenser 66.
Thus, refrigerant from condenser 66 flows to bypass valve 80 within
refrigeration system 60 during operation of compressor 64. As an
example, bypass valve 80 may be a two-way valve, such as a two-way
solenoid valve. As another example, bypass valve 80 may be a
three-way valve, such as a three-way solenoid valve. Bypass conduit
82 fluidly couples bypass valve 80 and evaporator 70 such that
refrigerant at bypass valve 80 may flow through bypass conduit 82
to evaporator 70. As an example, bypass conduit 82 may be (e.g.,
aluminum or copper) tubing or piping that extends from bypass valve
80 to an inlet of evaporator 70. Thus, bypass valve 80 and
evaporator 70 may be in direct fluid communication with each other
via bypass conduit 82.
[0025] Bypass valve 80 is selectively adjustable between a normal
operating configuration and a bypass operating configuration. In
the normal operating configuration, refrigerant from condenser 66
flows through bypass valve 80 to expansion device 68 during
operation of compressor 64. Thus, refrigerant flows through
refrigeration system 60 in the manner described above with
reference to FIG. 2 when bypass valve 80 is in the normal operating
configuration such that refrigeration system 60 operates to cool
compartments 14 and 18 of refrigerator appliance 10. Conversely,
refrigerant from condenser 66 flows through bypass valve 80 to
evaporator 70 during operation of compressor 64 in the bypass
operating configuration. Thus, refrigerant from condenser 66
bypasses expansion device 68 in the bypass operating configuration
such that refrigeration system 60 does not operate to cool
compartments 14 and 18 of refrigerator appliance 10. By actuating
from the normal operating configuration to the bypass operating
configuration, bypass valve 80 may assist with implementing a
defrost cycle of refrigeration system 60. In the bypass operating
configuration, a mass flow rate of refrigerant through
refrigeration system 60 may be greater than when bypass valve 80 is
in the normal operating configuration, e.g., due to removal of
expansion device 68 from the flow path of refrigerant in
refrigeration system 60. In turn, heat transfer in evaporator 70
may increase in direct proportion to the mass flow increase, e.g.,
and thereby improve the efficiency of defrost cycles, as described
in greater detail below.
[0026] Refrigerant at an inlet of evaporator 70 is hotter when
bypass valve 80 is in the bypass operating configuration compared
to when bypass valve 80 is in the normal operating configuration.
Thus, refrigerant delivered to evaporator 70 via bypass conduit 82
may flow into evaporator 70 and heat evaporator 70 after shifting
bypass valve 80 from normal operating configuration to the bypass
operating configuration. By heating evaporator 70, the refrigerant
within evaporator 70 melts ice on an outer surface of evaporator 70
and thereby defrosts evaporator 70. Thus, bypass valve 80 and
bypass conduit 82 may assist with defrosting evaporator 70 by
bypassing refrigerant flow around expansion device 68 and
delivering refrigerant that is hotter than the freezing temperature
of water into evaporator 70. As an example, when bypass valve 80 is
in the bypass operating configuration, refrigerant entering
evaporator 70 from bypass conduit 82 may have a temperature no less
than sixty degrees Celsius (60.degree. C.). Heat may be evenly
distributed through evaporator 70 via refrigerant during defrost
cycles when bypass valve 80 is in the bypass operating
configuration. In contrast, standard defrosting methods utilizing
radiant heating elements adjacent an associated evaporator heat
only areas of the associated evaporator that are in line-of-sight
of the radiant heating element or in contact with the radiant
heating element.
[0027] As shown in FIG. 3, a drain trough 90 is disposed, e.g.,
directly, below evaporator 70. Drain trough 90 collects liquid
runoff from evaporator 70 during defrost cycles and directs the
liquid runoff away from evaporator 70. In such a manner, drain
trough 90 may assist with removing liquid water from compartments
14 and 18 during defrost cycles. Drain trough 90 may be made of any
suitable material, e.g., metal or plastic. From drain trough 90,
the liquid runoff from evaporator 70 may be directed to any
suitable location, such as a drain line out of refrigerator
appliance 10 or to an open topped evaporation pan 92 below
condenser 66. Thus, a drain line may extend from drain trough 90 to
an exterior drain or to evaporation pan 92 to dispose of the liquid
runoff from evaporator 70.
[0028] Drain trough 90 may be sized to assist with collecting
liquid runoff from evaporator 70. For example, an area or footprint
of drain trough 90, e.g., in a plane that is perpendicular to
vertical, may be larger than a corresponding area or foot print of
evaporator 70. In particular, drain trough 90 defines a length L.
The length L of drain trough 90 may be larger than a corresponding
length of evaporator 70 such that drain trough 90 is larger than
and extends past evaporator 70.
[0029] At least a portion of bypass conduit 82 may also be
positioned at and connected to drain trough 90. Thus, bypass
conduit 82 and drain trough 90 may be in conductive thermal
communication with each other. As an example, a portion of bypass
conduit 82 may be brazed or soldered to drain trough 90. As another
example, a portion of bypass conduit 82 may be clipped, fastened,
adhered or otherwise mounted to drain trough 90. By connecting
bypass conduit 82 to drain trough 90, heat transfer between bypass
conduit 82 and drain trough 90 may assist with melting ice within
drain trough 90 thereby assisting with proper operation of drain
trough 90. In certain exemplary embodiments, bypass conduit 82 is
positioned on and contacts drain trough 90 along the length L of
drain trough 90 in order to increase heat transfer between bypass
conduit 82 and drain trough 90.
[0030] As discussed above, bypass conduit 82 may be tubing or
piping. In certain exemplary embodiments, bypass conduit 82 may be
metal tubing, such as copper or aluminum tubing, having a circular
cross-section along a length of the metal tubing. Thus, bypass
conduit 82 may define an internal diameter, and the internal
diameter of bypass conduit 82 may be constant. The internal
diameter of bypass conduit 82 may be selected to match adjacent
sections of tubing or piping within refrigeration system 60. For
example, the internal diameter of bypass conduit 82 may be selected
to match an exit line of condenser 66 and/or an inlet line of
evaporator 70. In such a manner, a pressure drop of refrigerant
within bypass conduit 82 between condenser 66 and evaporator 70
when bypass valve 80 is in the bypass operating configuration may
be limited or reduced.
[0031] Refrigeration system 60 also includes an electric heating
element 94, such as a resistance heating element, in certain
exemplary embodiments. Heating element 94 is positioned on and/or
mounted to bypass conduit 82. Thus, when activated, heating element
94 may heat bypass conduit 82 and refrigerant within bypass conduit
82. In certain exemplary embodiments, heating element 94 may be
encased within foam insulation of refrigerator 10, e.g., in a wall
of casing 12. Thus, heating element 94 may be spaced apart from
evaporator 70, e.g., such that refrigeration system 60 does not
include an electric heating element disposed at or exposed to an
outer surface of evaporator 70. Such positioning of heating element
94 can allow heating element 94 to increase a temperature of
refrigerant entering evaporator 70 during defrost cycles while also
limiting an operating temperature of heating element 94, as
discussed in greater detail below.
[0032] Refrigeration system 60 may be charged with a flammable
refrigerant, such as a flammable alkane, hydrocarbon or organic
compound. As another example, the flammable refrigerant may be
R600a. When charged with flammable refrigerant, a maximum operating
temperature of components within refrigerator appliance 10 may be
limited to no more than a maximum temperature, e.g., six hundred
and eighty degrees Fahrenheit (680.degree. F.). By positioning
heating element 94 in contact with bypass conduit 82, heat transfer
between heating element 94 and bypass conduit 82 may be both
radiant heat transfer and conductive heat transfer, and the maximum
operating temperature of heating element 94 may be no greater than
six hundred and eighty degrees Fahrenheit while heating element 94
operates to heat refrigerant entering evaporator 70 during defrost
cycles. In addition, positioning heating element 94 within foam
insulation may remotely position heating element 94 relative to
evaporator 70 such that heating element 94 is remotely positioned
relative to a space where refrigerant can collect within
refrigerator 10.
[0033] Components of refrigeration system 60 may also be operated
to assist defrosting of evaporator 70. For example, condenser fan
72 may be configured to deactivate whenever bypass valve 80 is in
the bypass operating configuration and bypass valve 80 directs
refrigerant from condenser 66 around expansion device 68 to
evaporator 70. In particular, a defrost cycle according to the
present subject matter may include a condenser preheat portion and
an evaporator defrost portion, e.g., that are performed
sequentially. Compressor 64 runs during the condenser preheat
portion of the defrost cycle. In addition, bypass valve 80 is in
the normal operating configuration and condenser fan 72 is
deactivated during the condenser preheat portion of the defrost
cycle. Thus, a temperature of condenser 66 increases while
compressor 64 is running during the condenser preheat. By
deactivating condenser fan 72 and reducing convective heat transfer
between condenser 66 and ambient air about condenser 66, condenser
66 may function as a thermal capacitor during the condenser preheat
portion of the defrost cycle and thereby provide thermal energy to
other components of refrigeration system 60 during later portions
of the defrost cycle, as discussed in greater detail below.
[0034] After the condenser preheat portion of the defrost cycle,
bypass valve 80 shifts or actuates from the normal operating
configuration to the bypass operating. Thus, after increasing the
temperature of condenser 66 during the preheat portion of the
defrost cycle, bypass valve 80 actuates to the bypass operating
configuration such that refrigerant from condenser 66 bypasses
expansion device 68 and flows to evaporator 70 via bypass conduit
82.
[0035] After actuating bypass valve 80 to the bypass operating
configuration, compressor 64 runs during the evaporator defrost
portion of the defrost cycle. As discussed above, the temperature
of condenser 66 increases while compressor 64 is running during the
condenser preheat. Conversely, the temperature of condenser 66
decreases while compressor 64 is running during the evaporator
defrost portion of the defrost cycle. In particular, heat transfer
between condenser 66 and refrigerant within condenser 66 may
increase the temperature of refrigerant exiting condenser 66, and
the heated refrigerant from condenser 66 may flow to evaporator 70
via bypass conduit 82 in order to defrost evaporator 70, as
discussed above. In such a manner, the mass of condenser 66 may
provide thermal storage for later portions of the defrost cycle.
Condenser fan 72 may also be deactivated during the evaporator
defrost portion of the defrost cycle in order to limit heat
transfer between condenser 66 and ambient air about condenser 66.
Further, heating element 94 may be activated during the evaporator
defrost portion of the defrost cycle in order to heat refrigerant
within bypass conduit 82.
[0036] Defrosting evaporator 70 in the manner discussed above can
have numerous potential benefits. For example, evaporator 70 may be
defrosted more efficiently using refrigerant from condenser 66
compared to systems using radiant heating elements to defrost an
evaporator. In addition, heating element 94 may be positioned at
and operate in an area with reduced risk for flammability of an
organic compound. Further, defrosting without an exposed radiant
heating element in freezer compartment 18 can reduce or eliminate
freezer burn on food items stored in the freezer compartment
18.
[0037] FIG. 4 provides a schematic view of evaporator 70 and bypass
conduit 82. As may be seen in FIG. 4, evaporator 70 may include a
conduit 100 that extends, e.g., longitudinally, between an inlet
102 and an outlet 104. Conduit 100 may be any suitable tubing,
piping, etc. for containing a flow of refrigerant. As a particular
example, conduit 100 may include a continuous piece of aluminum or
copper tubing that extends from inlet 102 of conduit 100 to outlet
104 of conduit 100. When bypass valve 80 is in the bypass operating
configuration, a flow of refrigerant within refrigeration system 60
enters conduit 100 at inlet 102 of conduit 100. Conduit 100 guides
or directs the flow of refrigerant through conduit 100 to outlet
104 of conduit 100. From outlet 104, the flow of refrigerant may
return to compressor 64. Bypass conduit 82 may be coupled to
conduit 100 at or adjacent inlet 102 of conduit 100.
[0038] Conduit 100 also extends between or includes a top portion
103 and a bottom portion 105. Top portion 103 and bottom portion
105 of conduit 100 may be spaced apart from each other, e.g., along
a vertical direction V. In particular, top portion 103 of conduit
100 may be positioned above bottom portion 105 of conduit 100,
e.g., along the vertical direction V. Inlet 102 and outlet 104 of
conduit 100 may both be positioned at or adjacent top portion 103
of conduit 100.
[0039] Conduit 100 may be bent or formed into any suitable shape.
For example, as shown in FIG. 4, conduit 100 may be bent or formed
to include a serpentine segment or section 108 and a linear segment
or section 109. Linear section 109 of conduit 100 may be disposed
or formed downstream of serpentine section 108 of conduit 100
relative to the flow of refrigerant through conduit 100. Serpentine
section 108 of conduit 100 includes a plurality of bends. Thus,
refrigerant flowing through serpentine section 108 of conduit 100
may change directions multiple times. Serpentine section 108 of
conduit 100 may be provided or formed in order to permit conduit
100 to have a long length between inlet 102 and outlet 104 of
conduit 100 while also reducing a foot print of evaporator 70
within refrigerator 10. Linear section 109 of conduit 100 extends
from bottom portion 105 of conduit 100 to top portion 103 of
conduit 100. Thus, after flowing through serpentine section 108 of
conduit 100 from top portion 103 to bottom portion 105 of conduit
100, the refrigerant within conduit 100 may flow back towards top
portion 103 of conduit 100 (e.g., and outlet 104) via linear
section 109 of conduit 100.
[0040] Conduit 100 may also include a pair of jumper tubes, each
positioned at a respective one of inlet 102 and outlet 104 of
conduit 100. The jumper tubes may assist with coupling evaporator
70 to other components of refrigeration system 60. For example, as
discussed above, conduit 100 may include aluminum tubing between
inlet 102 and outlet 104 of conduit 100. In contrast, the jumper
tubes may be copper tubing. Copper tubing can be significantly
easier to join together with solder compared to aluminum tubing.
Thus, the jumper tubes may facilitate connection of evaporator 70
into refrigeration system 60 by providing a connection point to
adjacent tubing. For example, bypass conduit 82 may be coupled to
the jumper tube at inlet 102 of conduit 100.
[0041] Conduit 100 also defines an outer surface 106. A spine fin
heat exchanger 110 is wound onto conduit 100 at outer surface 106
of conduit 100. In particular, spine fin heat exchanger 110 may
form a helix on outer surface 106 of conduit 100. Spine fin heat
exchanger 110 assist with heat transfer between air passing over
evaporator 70 and refrigerant flowing through conduit 100, e.g., by
increasing a heat exchange surface exposed to the air about
evaporator 70.
[0042] As shown in FIG. 4, bypass conduit 82 includes a first
segment or section 120 and a second segment or section 122. First
section 120 of bypass conduit 82 is positioned on and/or mounted to
drain trough 90. Conversely, second section 122 of bypass conduit
82 is positioned above drain trough 90, e.g., along the vertical
direction V. In particular, second section 122 of bypass conduit 82
may span or be positioned within a gap between evaporator 70 and
drain trough 90, e.g., along the vertical direction V. Thus, second
section 122 of bypass conduit 82 may be positioned between
evaporator 70 and drain trough 90, e.g., along the vertical
direction V. Second section 122 of bypass conduit 82 may assist
with limiting ice accumulation between evaporator 70 and drain
trough 90.
[0043] Plate fins 124 may be mounted to bypass conduit 82 at second
section 122 of bypass conduit 82. For example, second section 122
of bypass conduit 82 may be bent into a serpentine pattern, and
plate fins 124 may extend between windings or coils of second
section 122 of bypass conduit 82. Plate fins 124 assist with heat
transfer between air passing over bypass conduit 82 and refrigerant
flowing through second section 122 of bypass conduit 82, e.g., by
increasing a heat exchange surface exposed to the air about bypass
conduit 82. Plate fins 124 also may further assist with limiting
ice accumulation between evaporator 70 and drain trough 90.
[0044] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they include structural elements that do not
differ from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
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