Refrigeration – Gas compression – heat regeneration and expansion – e.g.,...
Reexamination Certificate
2001-07-27
2003-03-18
Doerrler, William C. (Department: 3744)
Refrigeration
Gas compression, heat regeneration and expansion, e.g.,...
C062S457900, C062S275000, C062S239000
Reexamination Certificate
active
06532749
ABSTRACT:
FIELD OF THE INVENTION
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/or a cooled area.
BACKGROUND OF THE INVENTION
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.
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.
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.
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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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 Stirlin
Graber James M.
Lehman Joseph M.
Musgrave Dwight S.
Rotsaert Jean-Marc
Rudick Arthur G.
Doerrler William C.
Sutherland, Ashbill & Brennan LLP
The Coca-Cola Company
LandOfFree
Stirling-based heating and cooling device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Stirling-based heating and cooling device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stirling-based heating and cooling device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3062492