Abstract:
A refrigerator is provided. The refrigerator includes a freezer compartment having a freezer door, an ice maker in communication with an ice dispensing system, the ice dispensing system has an ice delivery conduit extending through the freezer door, and a heating element positioned proximate to the ice dispensing system to provide heat to the ice dispensing conduit. The refrigerator further includes a controller operationally coupled to the heating element, the controller providing variable wattage to the heating element.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates generally to refrigerators, and more particularly, to controlling heating within such refrigerators. 
   Some known refrigerators include a fresh food compartment and a freezer compartment. Such a refrigerator also typically includes a refrigeration circuit including a compressor, evaporator, and condenser connected in series. An evaporator fan is provided to blow air over the evaporator, and a condenser fan is provided to blow air over the condenser. In operation, when an upper temperature limit is reached in the freezer compartment, the compressor, evaporator fan, and condenser fan are energized. Once the temperature in the freezer compartment reaches a lower temperature limit, the compressor, evaporator fan, and condenser fan are de-energized. 
   An ice maker may be located in the freezer compartment and operable to make ice cubes. A through-the-door ice and water dispenser may be provided to deliver ice and water to a user without the user opening the refrigerator doors. Known through the door ice dispensers include a front opening in an ice chute through which ice is dispensed. Ice dispensers typically have a duct door covering the front opening that prevents warm moist air from entering the refrigerator compartment. With such an ice dispensing apparatus, it is possible that external sweating, i.e., moisture or condensation, will appear in the ice dispenser area under high temperature or high humidity conditions. This sweating results from the relatively low temperature inside the chute and the ambient conditions to which the duct door is exposed. 
   Sweating has been reduced by applying heat to the areas likely to be affected by condensation. In some refrigerators this is accomplished by an electric heater positioned adjacent to the ice dispenser apparatus area. Similar heaters are positioned inside the ice dispenser apparatus or connected directly to the duct door. In other refrigerators, a hot gas loop is positioned inside the front face of the cabinet. 
   Electric heaters may not have an expected life as long as the refrigerator. Thus, a manufacturer may install two heaters, with the second to be used only if the first becomes inoperable. This increases the cost of all such refrigerators when only a small percentage of the second heaters will ever be needed. The use of electric heat facilitate reducing or preventing sweating requires additional energy from the refrigerator to supply the wattage to the electric heater to overcome sweating, thereby increasing energy costs. However, refrigerators must comply with government regulations with regard to energy usage. In order to comply, known refrigerators must decrease the amount of energy supplied to the electric heater resulting in decreased electric heater performance and an increase in sweating of the ice dispenser apparatus area and door duct. 
   BRIEF DESCRIPTION OF THE INVENTION 
   In one aspect, a refrigerator is provided. The refrigerator includes a freezer compartment having a freezer door, an ice maker in communication with an ice dispensing system, the ice dispensing system has an ice delivery conduit extending through the freezer door, and a heating element positioned proximate to the ice dispensing system to provide heat to the ice dispensing conduit. The refrigerator further includes a controller operationally coupled to the heating element, the controller providing variable wattage to the heating element. 
   In another aspect, an ice dispensing system for a freezer compartment of a refrigerator is provided. The freezer compartment has an ice maker and a freezer door. The ice dispensing system includes a dispensing conduit extending through the freezer door, the ice dispensing conduit is in communication with the ice maker, so as to pass ice through the freezer door, an ice dispensing conduit door is positioned proximate to the dispensing conduit, the conduit door is moveable between an open position and a closed position, a heating element positioned adjacent to the ice dispensing conduit door providing heat to the ice dispensing conduit door, and a controller operationally coupled to the heating element, the controller configured to modulate wattage to the heating element. 
   In a further aspect, a method for facilitating reduction of condensation on an ice dispensing apparatus of a refrigerator is provided. The method includes providing a heating element adjacent to the ice dispensing apparatus, and modulating a wattage supplied to the heating element. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of an exemplary refrigerator; and 
       FIG. 2  is a front view of an exemplary ice dispensing apparatus. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is a perspective view of an exemplary refrigerator  100  in which exemplary embodiments of the present invention may be practiced and for which the benefits of the invention may be realized. It is appreciated, however, that the herein described methods and apparatus may likewise be practiced in a variety of alternative refrigerators with modification apparent to those in the art. Therefore, refrigerator  100  as described and illustrated herein is for illustrative purposes only and is not intended to limit the herein described methods and apparatus in any aspect. 
     FIG. 1  illustrates a side-by-side refrigerator  100  including a fresh food storage compartment  102  and freezer storage compartment  104 . Freezer compartment  104  and fresh food compartment  102  are arranged side-by-side. In one embodiment, refrigerator  100  is a commercially available refrigerator from General Electric Company, Appliance Park, Louisville, Ky. 40225, and is modified to incorporate the herein described methods and apparatus. 
   It is contemplated, however, that the teaching of the description set forth below is applicable to other types of refrigeration appliances, including but not limited to top and bottom mount refrigerators wherein undesirable temperature gradients exist. The herein described methods and apparatus is therefore not intended to be limited to any particular type or configuration of a refrigerator, such as refrigerator  100 . 
   Refrigerator  100  includes a fresh food storage compartment  102  and a freezer storage compartment  104  contained within an outer case  106  and inner liners  108  and  110 . A space between case  106  and liners  108  and  110 , and between liners  108  and  110 , is filled with foamed-in-place insulation. Outer case  106  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. A bottom wall of case  106  normally is formed separately and attached to the case side walls and to a bottom frame that provides support for refrigerator  100 . Inner liners  108  and  110  are molded from a suitable plastic material to form freezer compartment  104  and fresh food compartment  102 , respectively. Alternatively, liners  108 ,  110  may be formed by bending and welding a sheet of a suitable metal, such as steel. The illustrative embodiment includes two separate liners  108 ,  110  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  112  extends between a case front flange and outer front edges of liners. Breaker strip  112  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  108 ,  110  is covered by another strip of suitable resilient material, which also commonly is referred to as a mullion  114 . Mullion  114  also preferably is formed of an extruded ABS material. Breaker strip  112  and mullion  114  form a front face, and extend completely around inner peripheral edges of case  106  and vertically between liners  108 ,  110 . Mullion  114 , insulation between compartments, and a spaced wall of liners separating compartments, sometimes are collectively referred to herein as a center mullion wall  116 . 
   Shelves  118  and slide-out drawers  120  normally are provided in fresh food compartment  102  to support items being stored therein. A bottom drawer or pan  122  may partly form a quick chill and thaw system (not shown) and selectively controlled, together with other refrigerator features, by a microprocessor (not shown) according to user preference via manipulation of a control interface  124  mounted in an upper region of fresh food storage compartment  102  and coupled to the microprocessor. A shelf  126  and wire baskets  128  are also provided in freezer compartment  104 . 
   Freezer compartment  104  includes an automatic ice maker  130  and a dispenser  131  is provided in freezer door  132  so that ice can be obtained without opening freezer door  132 . As will become evident below, ice maker  130 , in accordance with conventional ice makers includes a number of electromechanical elements that manipulate a mold to shape ice as it freezes, a mechanism to remove or release frozen ice from the mold, and a primary ice bucket for storage of ice produced in the mold. Periodically, the ice supply is replenished by ice maker  130  as ice is removed from the primary ice bucket. The storage capacity of the primary ice bucket is generally sufficient for normal use of refrigerator  100 . 
   Freezer door  132  and a fresh food door  134  close access openings to fresh food and freezer compartments  102 ,  104 , respectively. Each door  132 ,  134  is mounted by a top hinge  136  and a bottom hinge (not shown) 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  132  includes a plurality of storage shelves  138  and a sealing gasket  140 , and fresh food door  134  also includes a plurality of storage shelves  142  and a sealing gasket  144 . 
   In accordance with known refrigerators, refrigerator  100  also includes a machinery compartment (not shown) that at least partially contains components for executing a known vapor compression cycle for cooling air. The components include a compressor (not shown), a condenser (not shown), an expansion device (not shown), and an evaporator (not shown) connected in series and charged with a refrigerant. The evaporator is a type of heat exchanger which transfers heat from air passing over the evaporator to a refrigerant flowing through the evaporator, thereby causing the refrigerant to vaporize. The cooled air is used to refrigerate one or more refrigerator or freezer compartments via fans (not shown). Collectively, the vapor compression cycle components in a refrigeration circuit, associated fans, and associated compartments are referred to herein as a sealed system. The construction of the sealed system is well known and therefore not described in detail herein, and the sealed system is operable to force cold air through the refrigerator subject to the following control scheme. 
     FIG. 2  is a front view of one embodiment of ice dispenser  131 . Ice dispenser  131  includes an ice-discharge conduit or chute  160  passing through freezer door  132 . Chute  160  has an inlet  162  for receiving ice from ice maker  130  and an outlet  164  for delivering ice to a user. Chute  160  extends through freezer door  132  in a downward direction for gravitational movement of the ice through chute  160 . 
   A closure, such as a duct door  170 , is mounted forwardly of outlet  164 . Duct door  170  is movable between an open position (shown in phantom lines), which permits ice to discharge through outlet  164  and a closed position, which seals chute  160 . The position of duct door  170  is controlled by an actuator (not shown) to maintain duct door in the second position when ice dispenser  131  is not in operation. The particular mounting structure, duct door, and actuating mechanism may take many known forms. 
   A heating element  180  is coupled to duct door  170  to facilitate reducing or preventing sweating of duct door  170 . In one embodiment, heating element  180  is an electrical resistance wire, as is known in the art, and is embedded in or attached to duct door  170 . In another embodiment, heating element  180  is adjacent to duct door  170  facilitate reducing or preventing sweating of duct door  170  and chute  160 . In a further embodiment, heating element  180  is proximate to duct door  170 , so as so provide sufficient amount of heat facilitate reducing or preventing sweating in and around the ice dispenser  131  area. 
   A controller (not shown), such as a microprocessor, controls the operation of the refrigerator by directing energy to the various electrical components of refrigerator  100 . The controller modulates the wattage to heating element  180  by various means. This allows use of a single heating element  180  for the reduction or prevention of sweating. Thus, the controller provides variable wattage to different components of refrigerator  100  as needed. For example, if heating element  180  does not require energy and refrigerator  100  needs to cool the air inside fresh food compartment  102 , the controller can direct power away from heating element  180  and send power to the vapor compressor cycle components. If sweating occurs, controller directs enough wattage to heating element  180  to eliminate sweating. Modulation of wattage to heating element  180  avoids the shortcomings of known heating elements which are limited in wattage usage due to energy restrictions. The modulation of wattage to heating element  180  allows for an increased amount of wattage to heating element  180 , such as, for example, ten watts, to eliminate sweating without exceeding energy usage restrictions. 
   In one embodiment, the controller modulates wattage to heating element  180  based on duty cycles. More specifically, the amount of wattage supplied to heating element  180  is almost directly proportional to the percentage of the duty cycle for heating element  180 . In another embodiment, the controller modulates wattage to heating element  180  by applied voltage. 
   In another embodiment, the controller modulates wattage to heating element  180  based on the size of refrigerator  100 . In another embodiment, heating element  180  is modular and capable of being incorporated into a variety of differently sized refrigerators. The controller provides variable wattage to heating element  180  based on the size of the refrigerator. In other words, a first refrigerator and a second refrigerator sized different than the first refrigerator both have the same heater. The heater in the first refrigerator is controlled at a wattage different than that of the second heater. 
   In another embodiment, the controller provides variable wattage to heating element  180  based on the frequency of use of the ice dispenser. In another embodiment, the controller provides variable wattage to heating element  180  based on the frequency of ice harvest within ice maker  130 . In another embodiment, the controller provides variable wattage to heating element based on a user defined control setting. In another embodiment, the controller provides variable wattage to heating element  180  based on the run times of refrigerator  100 , such as the run time of the compressor. In another embodiment, the controller applies a specific wattage to heater element  180  as part of a service fix. For example, when a refrigerator requires servicing from a repair person, the repair person may set a specific wattage for heater element  180 . 
   In another embodiment, the controller provides variable wattage based on a humidity sensor (not shown). In a further embodiment, the controller provides variable wattage to the heating element  180  based on temperature of the freezer compartment  104 . 
   The modulation of wattage permits the use of only one heating element to reduce or eliminate sweating, thereby reducing cost. Additionally, the same single heating element can be provided to different refrigerators, thereby further reducing part number and costs. 
   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.