U.S. patent application number 09/813637 was filed with the patent office on 2002-09-26 for stirling-based heating and cooling device.
Invention is credited to Graber, James M., Lehman, Joseph M., Musgrave, Dwight S., Rotsaert, Jean-Marc, Rudick, Arthur G..
Application Number | 20020134090 09/813637 |
Document ID | / |
Family ID | 25212976 |
Filed Date | 2002-09-26 |
United States Patent
Application |
20020134090 |
Kind Code |
A1 |
Rudick, Arthur G. ; et
al. |
September 26, 2002 |
Stirling-based heating and cooling device
Abstract
A device for heating a first article and cooling a second
article. The device may include an enclosure with a hot compartment
and a cold compartment. The device also may include a Stirling
cooler with a hot end and a cold end. The hot end may be positioned
in communication with the hot compartment so as to heat the first
article and the cold end may be positioned in communication with
the cold compartment so as to cool the second article.
Inventors: |
Rudick, Arthur G.; (Atlanta,
GA) ; Rotsaert, Jean-Marc; (Atlanta, GA) ;
Graber, James M.; (Columbus, OH) ; Lehman, Joseph
M.; (New Albany, OH) ; Musgrave, Dwight S.;
(Granville, OH) |
Correspondence
Address: |
SUTHERLAND ASBILL & BRENNAN LLP
999 PEACHTREE STREET, N.E.
ATLANTA
GA
30309
US
|
Family ID: |
25212976 |
Appl. No.: |
09/813637 |
Filed: |
March 21, 2001 |
Current U.S.
Class: |
62/6 ;
62/238.2 |
Current CPC
Class: |
F25D 23/12 20130101;
F25D 21/14 20130101; F25D 2331/805 20130101; F25D 2317/0661
20130101; F25D 2331/803 20130101; F25D 16/00 20130101; F25D 31/005
20130101; F25D 25/00 20130101; F25D 31/007 20130101; F25D 2400/12
20130101; F25B 9/14 20130101; F25D 17/06 20130101 |
Class at
Publication: |
62/6 ;
62/238.2 |
International
Class: |
F25B 009/00; F25B
027/00 |
Claims
We claim:
1. A device for heating a first article and cooling a second
article, said device comprising: an enclosure; said enclosure
comprising a hot compartment and a cold compartment; and a Stirling
cooler; said Stirling cooler comprising a hot end and a cold end
and wherein said hot end is positioned in communication with said
hot compartment so as to heat said first article and wherein said
cold end is positioned in communication with said cold compartment
so as to cool said second article.
2. The device of claim 1, wherein said enclosure comprises an
insulated divider positioned between said hot compartment and said
cold compartment.
3. The device of claim 2, wherein said Stirling cooler comprises a
regenerator positioned between said hot end and said cold end and
wherein said regenerator is positioned within said insulated
divider.
4. The device of claim 1, wherein said enclosure comprises a handle
for carrying said enclosure.
5. The device of claim 1, wherein said cold end of said Stirling
cooler comprises a cold end heat exchanger in communication
therewith.
6. The device of claim 1, wherein said cold compartment comprises a
Stirling cooler section with a fan.
7. The device of claim 6, wherein said cold compartment comprises a
product section with a product support for positioning said second
article thereon.
8. The device of claim 7, wherein said cold compartment comprises
an airflow path for circulating air through said Stirling cooler
section and said product section.
9. The device of claim 8, wherein said product support comprises a
plurality of apertures therein in communication with said airflow
path.
10. The device of claim 1, wherein said cold compartment comprises
a sensor for determining the temperature therein, said sensor in
communication with a controller.
11. The device of claim 10, wherein said enclosure comprises an
external vent positioned adjacent to said cold compartment and
wherein said controller is in communication with said external vent
so as to open said external vent when the temperature within said
cold compartment drops below a predetermined temperature.
12. The device of claim 10, wherein said enclosure comprises an
external sensor for determining the external temperature, said
external sensor in communication with said controller.
13. The device of claim 12, wherein said cold compartment comprises
a Stirling cooler section, a product section, and a divider
positioned therebetween.
14. The device of claim 13, wherein said divider comprises an
internal vent therein, said internal vent comprising an open
position to allow communication between said Stirling cooler
section and said product section and a closed position blocking
communication between said Stirling cooler section and said product
section.
15. The device of claim 14, wherein said internal vent comprises a
first internal vent positioned on a first side of said divider and
a second internal vent positioned on a second side of said
divider.
16. The device of claim 14, wherein the enclosure comprises a
plurality of external vents and wherein said controller is in
communication with said internal vent and said plurality of
external vents so as to close said internal vent and so as to open
said plurality of external vents when the temperature within said
cold compartment drops below a predetermined temperature and the
ambient temperature is below freezing.
17. The device of claim 1, wherein said hot end of said Stirling
cooler comprises a hot end heat exchanger in communication
therewith.
18. The device of claim 1, wherein said hot compartment comprises a
Stirling cooler section with a fan.
19. The device of claim 18, wherein said hot compartment comprises
a product section with a product support for positioning said first
article thereon.
20. The device of claim 19, wherein said hot compartment comprises
an airflow path for circulating air through said Stirling cooler
section and said product section.
21. The device of claim 1, wherein said hot compartment comprises a
sensor for determining the temperature therein.
22. The device of claim 21, wherein said enclosure comprises an
external vent positioned adjacent to said hot compartment and
wherein said sensor is in communication with said external vent so
as to open said external vent when the temperature within said hot
compartment rises above a predetermined temperature.
23. The device of claim 1, further comprising a wick extending from
about said cold end of said Stirling cooler in said cold
compartment to about said hot end of said Stirling cooler in said
hot compartment.
24. The device of claim 23, wherein said cold compartment comprises
a condensate collector positioned adjacent to said cold end of said
Stirling cooler and said wick.
25. A Stirling cooler driven device for use with ambient
temperatures above and below freezing, comprising: an enclosure;
said enclosure comprising a Stirling cooler section for positioning
said Stirling cooler therein, a product section, and a divider
positioned therebetween; said divider comprising an internal vent
therein; and said enclosure comprising a plurality of external
vents positioned adjacent to said Stirling cooler section.
26. The Stirling cooler driven device of claim 25, further
comprising an internal temperature sensor positioned within said
enclosure in communication with a controller and an external
temperature sensor positioned on said enclosure in communication
with said controller, said controller in communication with said
interior vent and said plurality of external vents.
27. The Stirling cooler driven device of claim 26, wherein said
controller opens at least a first one of said plurality of external
vents when the temperature within said enclosure drops below a
predetermined temperature and the ambient temperature is above
freezing.
28. The Stirling cooler driven device of claim 26, wherein said
controller closes said internal vent and opens said plurality of
external vents when the temperature within said enclosure drops
below a predetermined temperature and the ambient temperature is
below freezing.
29. The Stirling cooler driven device of claim 28, wherein said
predetermined temperature is below about thirty-two degrees
Fahrenheit (zero degrees Celsius).
30. The Stirling cooler driven device of claim 25, wherein said
internal vent comprising an open position to allow communication
between said Stirling cooler section and said product section and a
closed position blocking communication between said Stirling cooler
section and said product section.
31. The Stirling cooler device of claim 30, wherein said internal
vent comprises a first internal vent positioned on a first side of
said divider and a second internal vent positioned on a second side
of said divider.
32. A device for heating a first article with a hot end of a
Stirling cooler and cooling a second article with a cold end of the
Stirling cooler, said device comprising: a hot compartment with
said hot end of said Stirling cooler positioned therein; a cold
compartment with said cold end of said Stirling cooler positioned
therein; a hot compartment vent positioned adjacent to said hot
compartment; a cold compartment vent positioned adjacent to said
cold compartment; a hot compartment sensor positioned within said
hot compartment, said hot compartment sensor in communication with
said hot compartment vent so as to open said hot compartment vent
when the temperature within said hot compartment rises above a
first predetermined temperature; and a cold compartment sensor
positioned within said cold compartment, said cold compartment
sensor in communication with said cold compartment vent so as to
open said cold compartment vent when the temperature within said
cold compartments falls below a second predetermined
temperature.
33. A temperature-controlled device for use with an electrical
receptacle of a vehicle, comprising: a portable enclosure, said
portable enclosure comprising an interior space to be heated or
cooled; a Stirling cooler positioned about said enclosure and
providing heating or cooling to said interior space; and an
electrical line for powering said Stirling cooler via said
electrical receptacle.
34. A heating and cooling device comprising: an enclosure; said
enclosure comprising a hot compartment and a cold compartment; a
Stirling cooler; said Stirling cooler comprising a hot end heat
exchanger positioned in communication with said hot compartment and
a cold end heat exchanger positioned in communication with said
cold compartment; said hot compartment comprising a fan therein
positioned adjacent to said hot end heat exchanger; said cold
compartment comprising a condensate collector therein positioned
adjacent to said cold end heat exchanger so as to collect
condensate from said cold end heat exchanger; and a wick, said wick
extending from said condensate collector in said cold compartment
to said hot compartment so as to wick condensate from said
condensate collector to said hot compartment and so as to evaporate
said condensate via an air stream produced by said fan.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to refrigeration and
heating systems and more specifically relates to an apparatus
driven by a Stirling cooler and having a heated area and a cooled
area.
BACKGROUND OF THE INVENTION
[0002] Known refrigeration systems generally have used conventional
vapor compression Rankine cycle devices to chill a given space. In
a typical Rankine cycle apparatus, the refrigerant in the vapor
phase is compressed in a compressor so as to cause an increase in
temperature. The hot, high-pressure refrigerant is circulated
through a heat exchanger, called a condenser, where it is cooled by
heat transfer to the surrounding environment. As a result, the
refrigerant condenses from a gas back to a liquid. After leaving
the condenser, the refrigerant passes through a throttling device
where the pressure and the temperature are reduced. The cold
refrigerant leaves the throttling device and enters a second heat
exchanger, called an evaporator, located in or near the
refrigerated space. Heat transfer with the evaporator and the
refrigerated space causes the refrigerant to evaporate or to change
from a saturated mixture of liquid and vapor into a superheated
vapor. The vapor leaving the evaporator is then drawn back into the
compressor so as to repeat the refrigeration cycle.
[0003] Attempts to use such a Rankine cycle system to refrigerate a
portable device, however, have been largely unsuccessful. The
typical components of a Rankine cycle system are generally too
large, too heavy, and too loud. Further, such systems generally
contain noxious or greenhouse gases. As a result, most Rankine
cycle systems are used for stationary refrigeration devices.
[0004] Similarly, attempts have been made to use the waste heat
generated in a Rankine cycle system to provide heat to a warming
compartment spaced apart from the refrigeration area. Although
waste heat is generated, the relatively large and cumbersome
configuration required by a Rankine cycle system, may make it
difficult to transfer effectively the waste heat to the warming
compartment. Separating the refrigeration components and the
warming compartment generally may lessen the efficiency of the
system as a whole.
[0005] One alternative to the use of a Rankine cycle system is a
Stirling cycle cooler. The Stirling cycle cooler is also a
well-known heat transfer mechanism. Briefly described, a Stirling
cycle cooler compresses and expands a gas (typically helium) to
produce cooling. This gas shuttles back and forth through a
regenerator bed to develop much greater temperature differentials
than may be produced through the normal Rankine compression and
expansion process. Specifically, a Stirling cooler may use a
displacer to force the gas back and forth through the regenerator
bed and a piston to compress and expand the gas. The regenerator
bed may be a porous element with significant thermal inertia.
During operation, the regenerator bed develops a temperature
gradient. One end of the device thus becomes hot and the other end
becomes cold. See David Bergeron, Heat Pump Technology
Recommendation for a Terrestrial Battery-Free Solar Refrigerator,
September 1998. Patents relating to Stirling coolers include U.S.
Pat. Nos. 5,678,409; 5,647,217; 5,638,684; 5,596,875 and 4,922,722,
all incorporated herein by reference.
[0006] Stirling cooler units are desirable because they are
nonpolluting, efficient, and have very few moving parts. The use of
Stirling coolers units has been proposed for conventional
refrigerators. See U.S. Pat. No. 5,438,848, incorporated herein by
reference. The integration of a free-piston Stirling cooler into a
conventional refrigerated cabinet, however, requires different
manufacturing, installation, and operational techniques than those
used for conventional compressor systems. See D. M. Berchowitz et
al., Test Results for Stirling Cycle Cooler Domestic Refrigerators,
Second International Conference. As a result, the use of the
Stirling coolers in refrigerators or similar devices is not well
known.
[0007] Likewise, the use of Stirling coolers in portable
refrigeration devices is not well known to date. Further, the use
of Stirling coolers to heat and to cool simultaneously separate
compartments of a device is not known. A need exists therefore for
adapting Stirling cooler technology to portable refrigeration and
heating devices.
SUMMARY OF THE INVENTION
[0008] The present invention thus provides for a device for heating
a first article and cooling a second article. The device may
include an enclosure with a hot compartment and a cold compartment.
The device also may include a Stirling cooler with a hot end and a
cold end. The hot end may be positioned in communication with the
hot compartment so as to heat the first article and the cold end
may be positioned in communication with the cold compartment so as
to cool the second article.
[0009] Specific embodiments of the present invention include the
use of an insulated divider positioned between the hot compartment
and the cold compartment. The Stirling cooler may include a
regenerator positioned between the hot end and the cold end. The
regenerator may be positioned within the insulated divider. The
enclosure may include a handle for carrying the enclosure.
[0010] The cold end of the Stirling cooler may include a cold end
heat exchanger. The cold compartment may include a Stirling cooler
section with a fan, a product section with a product support for
positioning the second article thereon, and an airflow path for
circulating air through the Stirling cooler section and the product
section. The product support may include a number of apertures
therein in communication with the airflow path.
[0011] The cold compartment may include a sensor for determining
the temperature therein. The sensor may be in communication with a
controller. The enclosure may include an external vent positioned
adjacent to the cold compartment. The controller may be in
communication with the external vent so as to open the vent when
the temperature within the cold compartment drops below a
predetermined temperature.
[0012] The cold compartment also may include a divider positioned
between the Stirling cooler section and the product section. The
divider may include an internal vent therein. The internal vent may
include a first internal vent positioned on a first side of the
divider and a second internal vent positioned on a second side of
the divider. The enclosure may include a number of external vents
positioned adjacent to the cold compartment. The controller may be
in communication with the internal vent and the external vents so
as to close the internal vent and so as to open the external vents
when the temperature within the cold compartment drops below a
predetermined temperature and the ambient temperature is below
freezing.
[0013] The hot end of the Stirling cooler may include a hot end
heat exchanger. The hot compartment may include a Stirling cooler
section with a fan, a product section with a product support for
positioning the first article thereon, and an airflow path for
circulating air through the Stirling cooler section and the product
section. The hot compartment may include a sensor for determining
the temperature therein. The enclosure may include an external vent
positioned adjacent to the hot compartment. The sensor may be in
communication with the external vent so as to open the vent when
the temperature within the hot compartment rises above a
predetermined temperature.
[0014] The device may further include a wick extending from about
the cold end of the Stirling cooler in the cold compartment to
about the hot end of the Stirling cooler in the hot compartment.
The cold compartment may include a condensate collector positioned
adjacent to the cold end of the Stirling cooler and the wick so as
to collect condensate and wick it to the hot compartment.
[0015] A further embodiment of the present invention may provide
for a Stirling cooler driven device for use with ambient
temperatures above and below freezing. The device may include an
enclosure. The enclosure may include a Stirling cooler section for
positioning the Stirling cooler therein, a product section, and a
divider positioned therebetween. The divider may include an
internal vent. The enclosure may include a number of external vents
positioned adjacent to the Stirling cooler section.
[0016] The device also may include an internal temperature sensor
positioned within the enclosure and an external temperature sensor
positioned on the enclosure. The sensors may be in communication
with a controller. The controller may open at least a first one of
the external vents when the temperature within the enclosure drops
below a predetermined temperature and the ambient temperature is
above freezing. The controller may close the internal vent and open
the external vents when the temperature within the enclosure drops
below the predetermined temperature and the ambient temperature is
below freezing. The predetermined temperature may be below about
thirty-two degrees Fahrenheit (zero degrees Celsius).
[0017] A further embodiment of the present invention may provide
for a device for heating a first article with a hot end of a
Stirling cooler and cooling a second article with a cold end of the
Stirling cooler. The device may include a hot compartment with the
hot end of the Stirling cooler positioned therein and a cold
compartment with the cold end of the Stirling cooler positioned
therein. A hot compartment vent may be positioned adjacent to the
hot compartment and a cold compartment vent may be positioned
adjacent to the cold compartment. A hot compartment sensor may be
positioned within the hot compartment. The hot compartment sensor
may be in communication with the hot compartment vent so as to open
the vent when the temperature within the hot compartment rises
above a first predetermined temperature. A cold compartment sensor
may be positioned within the cold compartment. The cold compartment
sensor may be in communication with the cold compartment vent so as
to open the vent when the temperature within the cold compartments
falls below a second predetermined temperature.
[0018] A further embodiment of the present invention provides for a
temperature-controlled device for use with an electrical receptacle
of a vehicle. The device may include a portable enclosure. The
portable enclosure may have an interior space to be heated or
cooled, a Stirling cooler positioned about the enclosure for
providing heating or cooling to the interior space, and an
electrical line for powering the Stirling cooler via the electrical
receptacle.
[0019] A further embodiment of the present invention may provide
for a heating and cooling device. The device may include an
enclosure with a Stirling cooler, a hot compartment, and a cold
compartment. The Stirling cooler may have a hot end heat exchanger
positioned in communication with the hot compartment and a cold end
heat exchanger positioned in communication with the cold
compartment. The hot compartment may include a fan positioned
adjacent to the hot end heat exchanger. The cold compartment may
include a condensate collector positioned adjacent to the cold end
heat exchanger so as to collect condensate from the cold end heat
exchanger. The device also may include a wick. The wick may extend
from the condensate collector in the cold compartment to the hot
compartment so as to wick condensate from the condensate collector
to the hot compartment and so as to evaporate the condensate via an
air stream produced by the fan.
[0020] Other objects, features, and advantages of the present
invention will become apparent upon review of the following
specification, when taken in conjunction with the drawings and the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a top plan view of a Stirling cooler unit.
[0022] FIG. 2 is an end plan view of the Stirling cooler unit of
FIG. 1.
[0023] FIG. 3 is a perspective view of the heating/cooling device
of the present invention.
[0024] FIG. 4 is a side cross-sectional view of the heating/cooling
device taken along line 4-4 of FIG. 3.
[0025] FIG. 5 is a side cross-sectional view of the heating/cooling
device taken along line 4-4 of FIG. 3 with the cooling compartment
vent open.
[0026] FIG. 6 is a side cross-sectional view of the heating/cooling
device taken along line 4-4 of FIG. 3 with the heating compartment
vent open.
[0027] FIG. 7 is a partial side cross-sectional view of an
alternative embodiment of the heating/cooling device with the
external vents closed and the internal vents open.
[0028] FIG. 8 is a partial side cross-sectional view of the
alternative embodiment of the heating/cooling device of FIG. 7 with
one of the external vents open.
[0029] FIG. 9 is a partial side cross-sectional view of the
alternative embodiment of the heating/cooling device of FIG. 7
showing the external vents open and the internal vents closed.
[0030] FIG. 10 is a partial side cross-sectional view of an
alternative embodiment of the present invention showing a
condensate collection system.
DETAILED DESCRIPTION OF THE INVENTION
[0031] Referring now to the drawings in which like numerals
indicate like elements throughout the several views, FIGS. 1 and 2
show a Stirling cooler 100 for use with the present invention. As
is well known, the Stirling cooler 100 may include a cold end 110
and a hot end 120. A regenerator 130 may separate the cold end 110
and the hot end 120. The Stirling cooler 100 may be driven by a
free piston (not shown) positioned within a casing 140. The Global
Cooling Company of Athens, Ohio may manufacture a Stirling cooler
100 suitable for use with the present invention. Any conventional
type of free piston Stirling cooler 100, however, may be used
herein. Any numbers of the Stirling coolers 100 also may be used.
The size and the number of the Stirling coolers 100 used herein may
depend upon the size and the capacity of the refrigeration system
as a whole.
[0032] A cold end heat exchanger 150 may be located on the cold end
110 of the Stirling cooler 100. The cold end heat exchanger 150 may
be a cross-flow finned heat exchanger or any conventional type of
heat exchange device. The heat exchanger 150 may be made out of
copper, aluminum, or similar types of materials. A hot end heat
exchanger 160 may be positioned on the hot end 120 of the Stirling
cooler 100. The hot end heat exchanger 160 also may be a cross-flow
finned heat exchanger or a similar type of device. The heat
exchanger 160 also may be made out of copper, aluminum, or similar
types of materials. The size of the heat exchangers 150, 160 may
depend upon the size of the Stirling cooler 100 as a whole.
[0033] FIGS. 3-6 show a heating/cooling container 200 of the
present invention. The heating/cooling container 200 may include an
insulated outer shell 210. The insulated outer shell 210 may be
made out of expanded polystyrene foam, polyurethane foam, or
similar types of insulated materials. The insulated outer shell 210
may include a number of doors 220. For example, a hot compartment
door 230 and a cold compartment door 240 are shown. The doors 220
may each have a handle 250 and may be attached to the insulated
outer shell 210 by a conventional hinge 260 or a similar device.
The insulated outer shell 210 also may have a handle 270 for
carrying the heater/cooler container 200. The container 200 also
may have a power cord 280 to power the Stirling cooler or coolers
100 therein. The power cord 280 may plug into a conventional
electric outlet or into an electrical receptacle such as, for
example, an automobile lighter compartment. Alternatively, a
conventional battery pack also may be used.
[0034] A temperature sensor 285 may be positioned on the outer
shell 210 so as to determine the ambient temperature. The sensor
285 may be a conventional temperature sensor such as a
thermocouple, a thermistor, or similar types of devices. The sensor
285 also may be in communication with a controller as described in
more detail below.
[0035] The container 200 may have a hot compartment 290 and a cold
compartment 300. The hot compartment door 230 may be positioned
adjacent to the hot compartment 290 while the cold compartment door
240 may be positioned adjacent to the cold compartment 300. An
insulated divider 310 may separated the hot compartment 290 and the
cold compartment 300. The insulated divider 310 may be out of
expanded polystyrene foam, polyurethane foam, or similar types of
materials with good insulating characteristics.
[0036] The Stirling cooler 100 may be positioned within the
container 200 such that the hot end 120 and the hot end heat
exchanger 160 are within or adjacent to the hot compartment 290
while the cold end 110 and the cold end heat exchanger 150 are
within or adjacent to the cold compartment 300. The regenerator 130
may be positioned, in whole or in part, within the insulated
divider 310.
[0037] The cold compartment 300 may have a non-insulated divider
320 and a support plate 330 positioned therein. The non-insulated
divider 320 may define a Stirling cooler section 340 and a product
section 350. The Stirling cooler section 340 may house the cold end
110 of the Stirling cooler 100 while the product section 350 may
house a number of products 355. The products 355 may include any
item intended to be chilled, such as a beverage container.
Likewise, the support plate 330 also defines the product section
350 and an airflow path 360. The support plate 330 may have a
number of apertures 370 therein that lead from the airflow path 360
to the product section 350. The airflow path 360 may extend through
the Stirling cooler section 340 and the product section 350.
[0038] Positioned within the Stirling cooler section 340 may be a
fan 380. Although the term "fan" 380 is used herein, the fan may be
any type of air movement device, such as a pump, a bellows, a
screw, and the like known to those skilled in the art. The Stirling
cooler section 340 also may include a shroud 390 positioned
therein. The shroud 390 may direct the flow of air through the fan
380 and into the airflow path 360.
[0039] A vent 410 may be formed in the outer insulated shell 210
adjacent to the Stirling cooler section 340 of the cold compartment
300. The vent 410 may be an open or shut door type device with a
door 412 and a movable hinge 414. The vent 410 may be in
communication with a sensor 420. The sensor 420 may be a
conventional temperature sensor such as a thermocouple, a
thermistor, or similar types of devices. The vent 410 and the
sensor 420 also may be in communication with a controller 430 so as
to open or shut the vent 410 depending upon the temperature as
sensed by the sensor 420 in relationship to the ambient temperature
as sensed by the external sensor 285. The controller 430 may be a
conventional microprocessor. The programming of the controller 430
may be in any conventional programming language. The controller 430
may be programmed so as to open the vent 410 if the temperature
within the cold compartment 300 drops below a given set point
temperature.
[0040] The hot compartment 290 also may include a non-insulated
divider 450 and a support plate 460. The non-insulated divider 450
may define a Stirling cooler section 470 and a product section 480
similar to that described above. The support plate 460 may define
an airflow path 490 communicating between the Stirling cooler
section 470 and the product section 480. The Stirling cooler
section 470 may include a fan 500. As described above, although the
term "fan" 500 is used herein, the fan 500 may be any type of air
movement device, such as a pump, a bellows, a screw, and the like
known to those skilled in the art. The fan 500 may circulate air
through the hot end heat exchanger 160, into the product section
480, and back through the air flow path 490. A number of hot
products 510 may be positioned on the support plate 460. The hot
products 510 may include any item intended to be heated, such as a
number of pizza boxes or other types of hot food containers.
[0041] The hot compartment 290 also may include a hot compartment
vent 520. As described above with respect to vent 410, the vent 520
may be an open or shut type device with a door 522 and a movable
hinge 524. The vent 520 may be in communication with a sensor 530
and the controller 430. The sensor 530 may be similar to the sensor
420 described above. The controller 430 may open the vent 520 when
the temperature as sensed by the sensor 530 rises above a given set
point.
[0042] In use, the cold products 355 that are either cold or
intended to be chilled are positioned on the support plate 330
within the cold compartment 300. Once the cold products 355 are
positioned therein, the fan 380 directs a flow of air through the
cold end heat exchanger 150 into the airflow path 360. The chilled
air then flows through the apertures 370 of the support plate 330
and across the cold products 355. The air then returns through the
cold end heat exchanger 150. This flow of air thus keeps the cold
products 355 chilled.
[0043] If the sensors 420 determine that the temperature within the
cold compartment 300 drops below a given temperature, for example
about 34 degrees Fahrenheit (1.1 degrees Celsius), the controller
430 may open the vent 410 to allow ambient air to circulate through
the cold compartment 300 if the ambient air temperature as sensed
by the external sensor 285 is above freezing. The vent 410 may
remain open until the temperature therein again rises above the set
point as determined by the sensor 420. Alternatively, the vent 410
may be opened proportionally to let in a varying amount of ambient
air. This system as a whole is designed for use where the ambient
temperature is above freezing.
[0044] Likewise, the hot products 510 or the products that are to
be warmed may be inserted onto the support plate 460 within the hot
compartment 290. The fan 500 may circulate air through the hot end
heat exchanger 160, into the product section 480, around the
products 510, through the air flow path 490, and back through the
fan 500. This flow of air thus keeps the hot products 510 warm.
[0045] If the sensor 530 determines that the temperature within the
hot compartment 290 is above a given set point, for example about
150 degrees Fahrenheit (65.6 degrees Celsius), the controller 430
may open the vent 520 so as to allow ambient air to circulate
through the hot compartment 290. The vent 520 may remain open until
the temperature therein again falls below the set point as
determined by the sensor 530. Alternatively, the vent 520 may be
opened proportionally to let in a varying amount of ambient
air.
[0046] The container 200 as a whole may be designed such that the
heat leak between the hot compartment 290 and the cold compartment
300, the heat leak from within the insulated inner shell 210 and
the ambient air, and the refrigeration lift of the Stirling cooler
100 are about in balance. For example, the following variables may
be used:
[0047] Q.sub.H=Heat flow through the wall 210 and the door 230 from
the hot compartment 290 to ambient;
[0048] Q.sub.C=Heat flow through the wall 210 and the door 240 from
ambient to the cold compartment 300;
[0049] Q.sub.D=Heat flow through the divider 310 from the hot
compartment 290 to the cold compartment 300;
[0050] Q.sub.S=Heat pumped by the Stirling cooler 100 from the cold
compartment 300 to the hot compartment 290;
[0051] Q.sub.W=Waste heat generated by the Stirling cooler 100 and
dumped into the hot compartment 290;
[0052] Q.sub.FH=Waste heat generated by the fan 500 and dumped into
the hot compartment 290; and
[0053] Q.sub.FC=Waste heat generated by the fan 380 and dumped into
the cold compartment 300.
[0054] Given a cold compartment 300 temperature (T.sub.C) of about
34 degrees Fahrenheit (1.1 degrees Celsius), a hot compartment
temperature (T.sub.H) of about 150 degrees Fahrenheit (65.6 degrees
Celsius), and an ambient temperature (T.sub.A) of about 75 degrees
Fahrenheit (24 degrees Celsius), the insulation of the container
200 and the power level of the Stirling cooler 100 may be selected
such that the following relationship is in place:
Q.sub.S=Q.sub.C+Q.sub.D+Q.sub.FC=Q.sub.H+Q.sub.D-Q.sub.W-Q.sub.FC
[0055] Specifically, the Stirling cooler 100 may have a capacity of
about 40 Watts with a hot compartment 290 having an area of about
2,000 cubic inches (about 32,744 cm.sup.3) and a cold compartment
300 having an area of about 1,000 cubic inches (about 16,387
cm.sup.3). Given these variables, the system as a whole can be used
in stabilized conditions with the hot compartment 290 and the cold
compartment 300 at their respective set points with little or no
need for opening the vents 410, 520.
[0056] FIGS. 7-9 show an alternative embodiment of the present
invention. The container 200 of FIGS. 3-6 may not be effective when
the ambient air temperature is below freezing. A container 550,
however, may be adapted to deal with such an environment. The
container 550 may be identical to the container 200 with the
exception that the non-insulated divider 320 is replaced with a
first divider 560 and a second divider 570. The dividers 560, 570
may be made out of plastic, metal, or similar materials. The
dividers 560, 570 may form an air pathway 580 therebetween.
[0057] Positioned on one of the dividers 560, 570 may be a first
internal vent 590. Positioned on the other end of the dividers 560,
570 may be a second internal vent 600. When closed, the internal
vents 590, 600 may separate the Stirling cooler section 340 from
the product section 300. The Stirling cooler section 340 also may
have an additional exterior vent 610 positioned within the
insulated outer shell 210. The vents 410, 590, 600, 610 may all
operate under the control of the controller 430 based upon the
temperature as sensed by the sensor 420 and the external sensor
285.
[0058] FIG. 7 shows the normal operating environment for the
container 550. In this environment, the exterior vents 410, 610 are
closed while the internal vents 590, 600 are opened. The cold
compartment 300 thus operates as described above with respect to
FIG. 4. Likewise, FIG. 8 shows the configuration of the container
500 when the ambient temperature is above freezing but the internal
temperature is below the set point. In this case, one or both of
the external vents 410, 610 may be open so as to allow ambient air
to circulate within the cold compartment 300 as shown in FIG.
6.
[0059] FIG. 9 shows the configuration of the container 500 when the
ambient temperature is below freezing and the temperature within
the cold compartment 300 is below the set point. In this situation,
the external vents 410, 610 may be open while the internal vents
590, 600 are closed. Closing the internal vents 590, 600
effectively isolates the product section 350 from the Stirling
cooler section 340. Air is thus drawn into the Stirling cooler
section 340 by the fan 380 and is directed through the air pathway
580 and through the cold end heat exchanger 150. The cold air is
then circulated back out through the second exterior vent 610. In
this case, the Stirling cooler 100 acts largely as a heat pump
without adding any additional refrigeration to the cold compartment
300.
[0060] FIG. 10 shows an alternative embodiment of the present
invention having a condensate collection system 700. The condensate
collection system 700 may use the heating/cooling container 200 as
described in detail herein with the Stirling cooler 100. The
condensate collection system 700 also may include a condensate
collector 710 attached to the non-insulated divider 320. The
condensate collector 710 may be made out of metal, plastic, or
similar types of somewhat rigid materials. The condensate collector
710 may extend from the non-insulated divider 320 along the length
of cold end heat exchanger 150.
[0061] The condensate collection system 700 also may have a wick
720 positioned adjacent to the condensate collector 710. The wick
720 may be made out of hydra chamois, polyester fabrics, synthetic
sponge (polyvinyl alcohol), or similar materials with wicking
characteristics. The wick 720 may extend from the condensate
collector 710, through the insulated divider 310, and into the hot
compartment 290 adjacent to the hot end heat exchanger 160. The
condensate collector 710 may be angled somewhat downward such that
the condensate will flow towards the wick 720. The wick 720 may be
mounted directly to the condensate collector 710 or to the inner
wall of the outer shell 210 so as to not interfere with the cold
air stream. The wick 720 may cover part of the condensate collector
710 so as to assist in absorption of the condensate.
[0062] Any condensate developed in the cold compartment 300 may
form about the cold end heat exchanger 150. The condensate then may
drip on to the condensate collector 710. The condensate may flow
down the condensate collector 710 towards the wick 720. The
condensate may then be absorbed by the wick 720. The wick 720 may
then carry the condensate through the insulated divider 310 and
into the hot compartment 290 adjacent to the hot end heat exchanger
160. The wick 720 may move the condensate by capillary action. As
such, the condensate is wicked to the hot compartment 290
regardless of the orientation of the heating/cooling container 200
as a whole, i.e., normal gravity does not play a significant role
in the wicking action. Once the condensate within the wick 720
reaches the hot compartment 290, the condensate may be evaporated
via the hot air stream flowing through the hot end heat exchanger
160.
[0063] It should be apparent that the foregoing relates only to the
preferred embodiments of the present invention and that numerous
changes and modifications may be made herein without departing from
the spirit and scope of the invention as defined by the following
claims.
* * * * *