U.S. patent application number 12/829102 was filed with the patent office on 2012-01-05 for refrigerant cooling device.
Invention is credited to Brent Alden Junge, Stephanos Kyriacou.
Application Number | 20120000240 12/829102 |
Document ID | / |
Family ID | 45398669 |
Filed Date | 2012-01-05 |
United States Patent
Application |
20120000240 |
Kind Code |
A1 |
Junge; Brent Alden ; et
al. |
January 5, 2012 |
REFRIGERANT COOLING DEVICE
Abstract
A refrigeration system for an appliance includes a compression
stage, a condenser stage, and an evaporation stage. The condenser
stage includes a first condenser coupled to the compression stage
and a pressure restriction device coupled between the first
condenser and the evaporation stage.
Inventors: |
Junge; Brent Alden;
(Evansville, IN) ; Kyriacou; Stephanos;
(Louisville, KY) |
Family ID: |
45398669 |
Appl. No.: |
12/829102 |
Filed: |
July 1, 2010 |
Current U.S.
Class: |
62/498 |
Current CPC
Class: |
F25D 23/003 20130101;
F25B 6/04 20130101; F25B 41/37 20210101 |
Class at
Publication: |
62/498 |
International
Class: |
F25B 1/00 20060101
F25B001/00 |
Claims
1. A refrigeration system for an appliance comprising: a
compression stage; a condenser stage; and an evaporation stage
coupled to the compression stage, wherein the condenser stage
comprises: a first condenser coupled to the compression stage; and
a pressure restriction device coupled between the first condenser
and the evaporation stage.
2. The refrigeration system of claim 1, wherein the pressure
restriction device comprises a capillary tube.
3. The refrigeration system of claim 2, wherein an inner diameter
of the capillary tube is substantially 0.08 inches.
4. The refrigeration system of claim 1, wherein the restriction
device is configured to reduce the pressure of a refrigerant
leaving the first condenser and entering the evaporator.
5. The refrigeration system of claim 1, wherein the restriction
device is configured to reduce a saturation temperature of
refrigerant flowing from the first condenser to the evaporator from
a condensing temperature to an ambient temperature level.
6. The refrigeration system of claim 1, further comprising a final
condenser coupled to the evaporation stage and wherein the pressure
restriction device is coupled between the first condenser and the
final condenser.
7. The refrigeration system of claim 6, wherein an inner diameter
of the capillary tube is substantially 0.035 inches.
8. The refrigeration system of claim 6, wherein the final condenser
is attached to a heat sink of the appliance.
9. The refrigeration system of claim 8, wherein the heat sink
comprises a portion of a cabinet for the appliance.
10. The refrigeration system of claim 1, further comprising a
capillary tube coupling the final condenser to the evaporation
stage.
11. The refrigeration system of claim 1, wherein the appliance is a
refrigerator.
12. The refrigeration system of claim 1, wherein the appliance is a
household air conditioning unit.
13. A refrigeration system for an appliance comprising: a
compression stage; a condenser stage; and an evaporation stage;
wherein the condenser stage comprises: a first condenser coupled to
the compression stage; a final condenser coupled to the evaporation
stage; and a pressure restriction device coupled between the first
condenser and the final condenser.
14. The refrigeration system of claim 13, wherein the pressure
restriction device comprises a capillary tube.
15. The refrigeration system of claim 14, wherein a length of the
capillary tube is in the range of 0.5 to 1.5 inches.
16. The refrigeration system of claim 15, wherein an inner diameter
of the capillary tube is substantially 0.035 inches.
17. The refrigeration system of claim 16, wherein the restriction
device is configured to reduce the pressure of a refrigerant
leaving the first condenser and entering the final condenser.
18. The refrigeration system of claim 13, wherein the restriction
device is configured to reduce a saturation temperature of
refrigerant flowing from the first condenser to the final condenser
from a condensing temperature to an ambient temperature level.
Description
BACKGROUND OF THE INVENTION
[0001] The present disclosure generally relates to refrigeration
systems, and more particularly to final condensing devices employed
in refrigeration systems.
[0002] Compressor-run refrigeration systems typically include a
compressor, a condenser, a metering device and an evaporator. These
systems consume contribute to the consumption of electrical energy
use. Since these systems often operate at relatively high ambient
temperatures, a significant amount of energy is generally required
to convert the liquid coolant flowing from the condenser to the
evaporator into a gas, and to raise the pressure of the gas from
the low side pressure found in the evaporator to the high side
pressure found in the condenser. New regulations and consumer
demand encourage the development of lower energy-use
appliances.
[0003] Various approaches to energy-saving appliances have been
developed including the use of vacuum panels that decrease the heat
entering the refrigerator. Sub-coolers are commonly used in larger
refrigeration systems to reduce the heat of the liquid refrigerant
flowing from the condenser into the evaporator, thereby increasing
heat absorption and decreasing the amount of energy use required.
However, the use of vacuum panels requires the addition of
expensive parts, thus increasing the total cost of the appliance
for a consumer.
[0004] Household consumer appliances often employ the use of the
simple capillary tube type of expansion or metering device.
Capillary tubes function as restriction devices or metering devices
by forcing the refrigerant entering the tube to be mostly liquid.
However, the capillary tube, which regulates the flow of the
refrigerant, occasionally allows a bubble of refrigerant vapor to
enter. This means that there is at least occasionally two-phase
refrigerant, liquid and gas, entering the capillary tube. When a
vapor bubble enters the capillary tube, the refrigerant mass flow
is greatly decreased while the low-density bubble travels the
length of the tube. When the refrigerant is sub-cooled, it is all
liquid and hard to control using a capillary tube. The presence of
vapor in the line or tube from the condenser to the evaporator can
significantly decrease the efficiency of the system by decreasing
the amount of liquid passing to the evaporator. This can make it
difficult to achieve sub-cooling repeatedly in a capillary type of
system, such as a refrigerator for example.
[0005] A sub-cooler, although also used to cool the refrigerant
entering an evaporator and produce a thermodynamic advantage, is
more suited for use in an expansion valve system used in commercial
industries. When used in a capillary system, such as in a household
refrigerator where capillary tubes are used as the expansion
devices, a two-phase mixture of refrigerant can result, which
cannot be sub-cooled. Sub-coolers can also be relatively expensive
making them less attractive for household consumer appliance
applications.
[0006] It would be advantageous to achieve the benefits of a
sub-cooler using a technique that is suitable for a capillary tube
system.
[0007] Accordingly, it would be desirable to provide a system that
addresses at least some of the problems identified above while also
being cost effective and easily adaptable to household
appliances.
BRIEF DESCRIPTION OF THE INVENTION
[0008] As described herein, the exemplary embodiments overcome one
or more of the above or other disadvantages known in the art.
[0009] One aspect of the exemplary embodiments is directed to a
refrigeration system for an appliance. In one embodiment the
refrigeration system comprises a compression stage, a condenser
stage, and an evaporation stage coupled to the compression stage.
The condenser stage includes a first condenser coupled to the
compression stage, and a pressure restriction device coupled
between the first condenser and the evaporation stage.
[0010] Another aspect of the exemplary embodiments relates to a
refrigeration system for an appliance. In one embodiment, the
refrigeration system includes a compression stage, a condenser
stage, and an evaporation stage. The condenser stage includes a
first condenser coupled to the compression stage, a final condenser
coupled to the evaporation stage and a pressure restriction device
is coupled between the first condenser and the final condenser.
[0011] These and other aspects and advantages of the exemplary
embodiments will become apparent from the following detailed
description considered in conjunction with the accompanying
drawings. It is to be understood, however, that the drawings are
designed solely for purposes of illustration and not as a
definition of the limits of the invention, for which reference
should be made to the appended claims. Moreover, the drawings are
not necessarily drawn to scale and that, unless otherwise
indicated, they are merely intended to conceptually illustrate the
structures and procedures described herein. In addition, any
suitable size, shape or type of elements or materials could be
used.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In the drawings:
[0013] FIG. 1A is a schematic diagram of an exemplary refrigeration
system incorporating aspects of the disclosed embodiments.
[0014] FIG. 1B is a schematic diagram of another exemplary
refrigeration system incorporating aspects of the disclosed
embodiments.
[0015] FIG. 2 illustrates an exemplary appliance incorporating
aspects of the disclosed embodiments.
[0016] FIG. 3 partially and schematically shows some of the
components of the refrigerator of FIG. 2, with one fresh food
compartment door open and the other being removed and the door for
the sub-compartment and the drawer/door for the freezer compartment
being removed.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS OF THE
INVENTION
[0017] Referring to FIG. 1A, an exemplary refrigeration system 100
for an appliance incorporating aspects of the disclosed embodiments
is illustrated. The aspects of the disclosed embodiments provide a
restriction device between the condenser and final condenser in a
capillary system to reduce the pressure of the refrigerant leaving
the condenser. This can drop the saturation temperature of the
refrigerant, which can result in an increase in cooling capacity
and a reduction in energy usage. Although the aspects of the
disclosed embodiments will generally be described herein with
respect to a refrigerator, in alternate embodiments, the aspects of
the disclosed embodiments can be applied to any refrigeration
system utilizing a capillary tube expansion system, including for
example, a household air conditioning system.
[0018] As is shown in FIG. 1A, the refrigeration system 100
includes an evaporation stage 12, a compression stage 14 disposed
downstream of the evaporation stage 12 and a condenser stage 16
disposed downstream of the compression stage 14. The refrigeration
system 100 includes therein a working medium (i.e., the
refrigerant). The compression stage 14 is generally configured to
compress the refrigerant received in a liquid low-pressure vapor
state from the evaporation stage 12 into a high-pressure gas vapor.
The compression stage 14 can generally comprise any conventional
compressor unit. From the compression stage 14, the high-pressure
refrigerant gas passes to the condenser stage 16 where the
refrigerant is condensed and heat is rejected to the ambient air.
In this embodiment, the condenser stage 16 includes an air-cooled
condenser, but the system 100 can also utilize water cooled units
or any other type of conventional condenser unit. The low-pressure
liquid refrigerant from the condenser stage travels to the
evaporation stage 12, where the low-pressure liquid refrigerant is
vaporized to absorb heat. The evaporation stage 12 is coupled to
and between the compression stage 14 and the condenser stage 16 in
a suitable manner, while the compression stage 14 is coupled to the
condenser stage 16 in a suitable manner.
[0019] In one embodiment, the evaporation stage 12 includes an
evaporator 102 and the compression stage 14 includes a compressor
104. As is shown in FIG. 1A, the condenser stage 16 includes a
condenser 106, a restriction device 108 and a final condenser 110,
suitably coupled together. In one embodiment, the liquefied
refrigerant passes from the condenser 106 through line 107 to a
restriction device 108. The restriction device 108 is placed after
the condenser 106 and before the final condenser 110. The
restriction device 108 is configured to reduce the pressure of the
refrigerant leaving the condenser 106 and entering the final
condenser 110. This will reduce the saturation temperature of the
refrigerant down from the condensing temperature, which is
typically in the range of approximately 10 to 15 degrees Fahrenheit
above the ambient temperature. In one embodiment, the restriction
device 108 comprises a piece of capillary tubing. Generally, the
restriction device 108 has a very short length, such as in the
range of approximately 0.5 to 2.0 inches, and preferably
approximately one (1) inch. An inner diameter of the restriction
device 108 can be in the range of approximately 0.025 to 0.045
inches, and preferably 0.035 inches or less. In alternate
embodiments, the restriction device 108 can be of any suitable size
that will enable the reduction of the temperature of the
refrigerant leaving the condenser 106 and entering the final
condenser 110 by approximately 10 to 15 degrees Fahrenheit in
saturation pressure, without concern for a mixture of liquid and
vapor refrigerant entering the evaporation stage 102. The
restriction device 108 is generally made from a heat conducting
material, such as copper or steel, for example.
[0020] In one embodiment, the system 100 can also include a
condenser loop 120. The condenser loop 120 can be placed downstream
of the condenser 106 and before the restriction device 108. The
condenser loop 120 generally comprises a length of tubing that is
placed near cold areas of the refrigerator doors to keep these
areas from sweating, particularly when humidity is high. Although
the condenser loop 120 is shown in FIGS. 1A and 1B, it is not
intended to limit the scope of the disclosed embodiments.
[0021] A refrigerant final condenser 110 is placed after the
condenser 106 to further reduce the temperature of the refrigerant
prior to entering the evaporator 102. The final condenser 106 is
generally compatible with capillary tube type expansion devices
typically found in consumer appliances, such as household
refrigerators.
[0022] Typically, the temperature of the refrigerant exiting the
condenser 106 will be in the range of approximately 100 to 105
degrees Fahrenheit when the appliance is operated in a 90 degree
Fahrenheit ambient. In this situation, the temperature of the
refrigerant exiting the final condenser 110 will be approximately
90 degrees Fahrenheit. By adding the restriction device 108 between
the condenser 106 and the final condenser 110, the saturation
temperature of the refrigerant is reduced from the condensing
temperature down to the ambient temperature. This allows the
refrigerant to be condensed by the final condenser 110 at a
temperature that is approximately the ambient temperature.
[0023] The refrigerant passes through line 109 to final condenser
110 where it is cooled before the refrigerant passes through line
111 to the evaporator 102. The low-pressure liquid line 111 extends
from the final condenser 110 to the evaporator 102 where the
refrigerant is vaporized to absorb heat. In one embodiment, the
line 111 is a length of capillary tubing. The length of the line
111 can be up to approximately 5 feet, and have, for example, an
inner diameter in the range of approximately 0.020 to 0.032 inches
or larger. In accordance with the aspects of the disclosed
embodiment, when the cooled refrigerant enters the evaporator 102
from the final condenser 110, it is at a lower enthalpy. This lower
enthalpy allows the refrigerant to absorb more heat in the
evaporator 102. Because the conditions at the compressor 104 are
unchanged, the compressor power is not changed. However, the
cooling capacity is increased, resulting in a decrease in overall
energy usage.
[0024] FIG. 1B illustrates another example of a cooling system
incorporating aspects of the disclosed embodiments. In comparison
to FIG. 1A, in this embodiment, the restriction device 108 is part
of, or comprises the final condenser 118 shown in FIG. 1B. The
final condenser 118 shown in FIG. 1B comprises a section of small
diameter tubing, such as a capillary tube, that is suitably sized
to provide the required pressure drop to achieve a reduction in
temperature. Generally, a pressure drop of approximately 20 psi
will reduce the saturation temperature of R-134 type refrigerant
approximately 10 degrees Fahrenheit, from approximately 100 degrees
Fahrenheit to approximately 90 degrees Fahrenheit. In one
embodiment, the final condenser 118 comprises a tube have a
internal diameter of approximately 0.08 inches, or generally in the
range of approximately 0.02 inches to 0.10 inches. A length of the
tube can be in the range of approximately ten to twenty feet.
[0025] Referring to FIGS. 2 and 3, an exemplary refrigerator 200
incorporating aspects of the disclosed embodiments is illustrated.
The refrigerator 200 has a main body 202 which defines therein a
first, upper, fresh food compartment 204 with a frontal access
opening 204A and a second, lower, freezer compartment 206 with a
frontal access opening 206A. The fresh food compartment 204 and the
freezer compartment 206 are arranged in a bottom mount
configuration where the fresh food compartment 204 is disposed or
positioned above the freezer compartment 206. In alternate
embodiments, any suitable arrangement of a fresh food compartment
and a freezer compartment can be utilized, other than including a
bottom mount configuration. The fresh food compartment 204 In FIG.
2 is shown with two French doors 208 and 210. However, a single
door can be used instead of the two doors 208, 210. The freezer
compartment 206 can be closed by a drawer or a door 212 in a known
or suitable manner.
[0026] The main body 202 of the refrigerator 200 includes a top
wall 230 and two sidewalls 232. The top wall 230 connects the
sidewalls 232 to each other at the top ends thereof. A mullion 234,
best shown in FIG. 3, connects the two sidewalls 232 to each other
and separates the fresh food compartment 204 from the freezer
compartment 206. The main body 202 also includes a bottom wall 234,
which connects the two sidewalls 232 to each other at the bottom
ends thereof, and a back wall 235.
[0027] FIG. 3 illustrates one embodiment of the refrigeration
system 100 of FIG. 1 incorporated in the refrigerator 200. The
sealed system 100 includes an evaporator 102 disposed in the
freezer compartment 206, a compressor 104 disposed downstream of
the evaporator 102 and outside of the freezer compartment 206, a
condenser 106 disposed downstream of the compressor 104, a
restriction device 108 disposed downstream of the condenser 106,
and a final condenser 110 disposed downstream of the restriction
device 108.
[0028] In one embodiment, the final condenser 110 is disposed on or
embedded in the cabinet portion 242 of the refrigerator body 202.
The cabinet 242 is generally a large heat sink that is
approximately at the ambient temperature and can be used to cool
refrigerant in the final condenser 110. Since the restriction
device 108 reduces the temperature of the refrigerant down to
approximately the ambient temperature, in one embodiment, the
refrigerant will be condensed by the final condenser 110 at a
temperature that is approximately the ambient temperature. Although
the final condenser 110 is shown disposed in the cabinet portion
242 of the freezer compartment 206, in alternate embodiments, the
final condenser 110 can be disposed on or in a cabinet portion 252
of the fresh food compartment 204, on the back portion 235 of the
main body 202 or other suitable heat exchanging plate in the
refrigerator 200. This allows the final condenser 110 to bring the
temperature of the refrigerant down to approximately that of the
refrigerator body 202, which is approximately ambient
temperature.
[0029] The aspects of the disclosed embodiments utilize a
restriction device between the condenser and evaporator to reduce
the saturation temperature of the refrigerant to approximately the
ambient temperature in a capillary tube refrigeration system. A
relatively short length of capillary tubing or other restriction is
used to reduce the pressure of the refrigerant leaving the
condenser. The restriction can be part of the final condenser or a
separate restriction device that is coupled between the condenser
and final condenser. This reduction in pressure can result in a
reduction of the temperature of the refrigerant leaving the
condenser to a temperature that is approximately the ambient
temperature, which can increase the cooling capacity of the
refrigerant entering the evaporator. In some instances, this can
result in a reduction of approximately 10-15 degrees Fahrenheit,
which can reduce energy usage and generate cost savings. In one
embodiment, an estimated 5% reduction in energy usage can be
anticipated.
[0030] Thus, while there have been shown and described and pointed
out fundamental novel features of the invention as applied to the
exemplary embodiments thereof, it will be understood that various
omissions and substitutions and changes in the form and details of
devices illustrated, and in their operation, may be made by those
skilled in the art without departing from the spirit of the
invention. For example, it is expressly intended that all
combinations of those elements and/or method steps which perform
substantially the same function in substantially the same way to
achieve the same results are within the scope of the invention.
Moreover, it should be recognized that structures and/or elements
and/or method steps shown and/or described in connection with any
disclosed form or embodiment of the invention may be incorporated
in any other disclosed or described or suggested form or embodiment
as a general matter of design choice. It is the intention,
therefore, to be limited only as indicated by the scope of the
claims appended hereto.
* * * * *