Abstract:
A 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 with 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.

Description:
BACKGROUND OF THE INVENTION 
   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. 
   BRIEF DESCRIPTION OF THE INVENTION 
   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. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates an exemplary refrigerator in accordance with one embodiment of the present invention; 
       FIG. 2  is a rear elevational schematic view of the refrigerator shown in  FIG. 1  including an exemplary sealed cooling system; and 
       FIG. 3  is a schematic view of a flow chart showing the operation of the sealed cooling system. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates an exemplary refrigeration appliance  10  in which the present invention may be practiced. In the embodiment described and illustrated herein, appliance  10  is a side-by-side refrigerator. It is recognized, however, that the benefits of the present invention are equally applicable to other types of refrigerators, freezers, and refrigeration appliances. Consequently, the description set forth herein is for illustrative purposes only and is not intended to limit the invention in any aspect. 
   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  FIG. 1 , and a closed position (not shown) closing the associated storage compartment. Freezer door  42  includes a plurality of storage shelves  46 , and fresh food door  44  includes a plurality of storage shelves  48 . 
     FIG. 2  is a rear elevational schematic view of refrigerator  10  (shown in  FIG. 1 ) including an exemplary sealed cooling system  60 . In accordance with known refrigerators, refrigerator  10  includes a machinery compartment  62  that at least partially contains components for executing a known vapor compression cycle for cooling air. The components include a compressor  64 , a condenser  66 , and an evaporator  68  connected in series and charged with a refrigerant. Evaporator  68  is a type of heat exchanger which transfers heat from air passing over the evaporator to a refrigerant flowing through evaporator  68  thereby causing the refrigerant to vaporize. As such, cooled air is produced and configured to refrigerate compartments  12 ,  14 . Collectively, the vapor compression cycle components in a refrigeration circuit, associated fans, and associated compartments are sometimes referred to as a sealed cooling system operable to force cold air through refrigeration compartments  12 ,  14 . In the exemplary embodiment, condenser  66  is arranged nearby the case flange of refrigerator  10 . 
   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. 
     FIG. 3  is a schematic view of a flow chart showing the operation of sealed cooling system  60 . In operation, when the power is turned on by a user, refrigerator  10  begins to work. In other words, cooling system  60  starts to run to cool fresh food compartment  12  and freezer compartment  14 . Compressor  64  is activated to draw refrigerant from evaporator  68  through suction tube  72  and discharge compressed refrigerant to condenser  66  via inlet tube  80 . From condenser  66 , refrigerant flows through three-way valve  86  and then to one of fluid paths A and B, based on detailed operating parameters, such as selected compartment temperature, operating temperature, ambient temperature, and others. During the process, detectors detect temperature factors, such as selected/operating temperature and ambient temperature. For instance, when the detectors detect that the selected temperature in fresh food compartment  12  is higher than the usual operating temperature, it is determined not to transfer excessive heat energy from fresh food compartment  12  to the outside environment through hot gas loop  78 , since use of hot gas loop  78  would lead to loss of energy efficiency. A feedback signal is sent to controller  88  which controls three-way valve  86  to switch refrigerant to filter dryer  76  and bypass hot gas loop  78 , as indicated by arrow B (shown in  FIG. 2 ). If it is determined to dissipate excessive heat outside fresh food compartment  12 , controller  88  controls three-way valve  86  to switch flow through hot gas loop  78 , as indicated by arrow A (shown in  FIG. 2 ). 
   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.