Patent Application
20070074524
This invention relates generally to refrigeration devices, and more particularly, to a cooling system method and apparatus for a refrigeration device to obtain maximum energy efficiency.
Recently, many countries around the world have established strict energy protection standards. Household refrigerators and freezers have been subject to some of these standards regarding the energy efficiency of these units.
Known refrigerators generally include a case defining at least one compartment for storage of food items, and a condenser/cooling system configured to provide a refrigeration result in the compartment, i.e., remove a certain amount of heat energy from the compartment to the outside environment. The condenser system is typically arranged in the case to transfer heat energy from the compartment to ambient environment outside the compartment. The transfer of this heat consumes energy.
While some of the improvement in energy efficiency has been obtained by improvement in the cabinet insulation, it has been found that improvements can be made in the refrigeration system itself. For example, a capillary tube and a hot gas loop are typically used in a condenser system of a refrigerator to improve cooling efficiency and reduce energy consumption. To improve heat exchange efficiency, increasing the lengths of the capillary tube and the hot gas loop has been adopted.
In one aspect, a cooling system for a refrigerator is provided. The cooling system includes a refrigerant, a condenser assembly configured to provide heat energy exchange with the refrigerant, and a hot gas loop in communication with the condenser assembly. The cooling system also includes a switching device coupled to the condenser assembly and the hot gas loop. The switching device provides at least two selectable fluid paths in the cooling system. The switching device is configured to channel the refrigerant along one of the fluid paths based on a thermal demand of the refrigerator.
In another aspect, a refrigerator is provided. The refrigerator includes a housing defining at least one chamber and a condenser system in which a refrigerant flows. The condenser system includes a condenser, a switching device, and a hot gas loop in flow communication with one another. The condenser system is configured to be in heat transfer relation to the chamber and the switching device is configured to allow the refrigerant to bypass the hot gas loop when a thermal demand of the refrigerator is met.
In still another aspect, a method of assembling a refrigerator is provided. The method includes providing a housing with a refrigeration chamber and arranging a sealed cooling system within the housing to provide a heat transfer from the refrigeration chamber, wherein the sealed cooling system includes a condenser, a hot gas loop and a switching device and wherein a refrigerant is circulated within the cooling system. The method further includes coupling the switching device within the cooling system, wherein the switching device provides different fluid paths in the sealed cooling system. The switching device is configured to channel the refrigerant along a first fluid path that bypasses the hot gas loop and a second fluid path through the hot gas loop. The method also includes operatively coupling a controller to the switching device, wherein the controller is configured to control the operation of the switching device.
Refrigerator 10 includes a fresh food storage compartment 12 and a freezer storage compartment 14. Freezer compartment 14 and fresh food compartment 12 are arranged side-by-side within an outer case 16 and defined by inner liners 18 and 20 therein. A space between case 16 and liners 18 and 20, and between liners 18 and 20, is filled with foamed-in-place insulation. Outer case 16 normally is formed by folding a sheet of a suitable material, such as pre-painted steel, into an inverted U-shape to form top and side walls of case 16. A bottom wall of case 16 normally is formed separately and attached to the case side walls and to a bottom frame that provides support for refrigerator 10. Inner liners 18 and 20 are molded from a suitable plastic material to form freezer compartment 14 and fresh food compartment 12, respectively. Alternatively, liners 18, 20 may be formed by bending and welding a sheet of a suitable metal, such as steel. The illustrative embodiment includes two separate liners 18, 20 as it is a relatively large capacity unit and separate liners add strength and are easier to maintain within manufacturing tolerances. In smaller refrigerators, a single liner is formed and a mullion spans between opposite sides of the liner to divide it into a freezer compartment and a fresh food compartment.
A breaker strip 22 extends between a case front flange and outer front edges of liners 18, 20. Breaker strip 22 is formed from a suitable resilient material, such as an extruded acrylo-butadiene-styrene based material (commonly referred to as ABS).
The insulation in the space between liners 18, 20 is covered by another strip of suitable resilient material, which also commonly is referred to as a mullion 24. In one embodiment, mullion 24 is formed of an extruded ABS material. Breaker strip 22 and mullion 24 form a front face, and extend completely around inner peripheral edges of case 16 and vertically between liners 18, 20. Mullion 24, insulation between compartments, and a spaced wall of liners separating compartments, sometimes are collectively referred to herein as a center mullion wall 26.
In addition, refrigerator 10 includes shelves 28 and slide-out storage drawers 30, sometimes referred to as storage pans, which normally are provided in fresh food compartment 12 to support items being stored therein.
Refrigerator 10 is controlled by a microprocessor (not shown) according to user preference via manipulation of a control interface 32 mounted in an upper region of fresh food storage compartment 12 and coupled to the microprocessor. A shelf 34 and wire baskets 36 are also provided in freezer compartment 14. In addition, an ice maker 38 may be provided in freezer compartment 14.
A freezer door 42 and a fresh food door 44 close access openings to fresh food and freezer compartments 12, 14, respectively. Each door 42, 44 is mounted to rotate about its outer vertical edge between an open position, as shown in
Besides compressor 64, condenser 66, and evaporator 68, sealed cooling system 60 also includes a suction tube 72 connected between compressor 64 and evaporator 68, a capillary tube 74, a filter dryer 76, and a hot gas loop 78 connected serially. An inlet tube 80 is utilized to connect compressor 64 with condenser 66 which allows refrigerant to flow from compressor 64 to condenser 66. A fan 82 and a fan motor 84 connected therewith are received in machinery compartment 62 close to compressor 64. Fan 82 is driven by fan motor 84 to force air across outer surfaces of compressor 64 and condenser 66 to enhance heat transfer from compressor 64 to condenser 66, respectively, to ambient air. Capillary tube 74 is in fluid communication with filter dryer 76. Hot gas loop 78 is in communication with both filter dryer 76 and condenser 66.
In the exemplary embodiment, a three-way valve 86 is operatively connected between condenser 66 and hot gas loop 78, and is also operatively connected to filter dryer 76. As such, three-way valve 86 provides the refrigerant in sealed system 60 with at least two selectable fluid paths, as shown in arrows A and B. Particularly, three-way valve 86 may be operated to be switchable to channel refrigerant along one of the fluid paths based on a predetermined thermal demand of refrigerator 10. An electronic controller 88 is operatively coupled to three-way valve 86 to control the operation of the valve and also operatively coupled to the microprocessor (not shown) of the refrigerator 10. It is contemplated that three-way valve 86, in alternative embodiments, could be replaced by other switching devices which can achieve the same function of switching the refrigerant from one path to another without departing from the spirit of the present invention.
Regardless of which path the refrigerant takes, the refrigerant enters filter dryer 76. The refrigerant continues to flow to capillary tube 74 from filter dryer 76 and then to evaporator 68 to transfer the heat energy from the compartments of refrigerator 10. Thus, a cooling circuit is formed with at least two selectable paths in refrigerator 10. The sealed system includes a hot gas loop and a three-way valve which allows refrigerant to bypass the hot gas loop during certain conditions. As such, energy efficiency is improved and energy is thus saved.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
