Patent Publication Number: US-8966929-B2

Title: Cooled air recirculation in a refrigerator

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to a refrigerator, and more particularly, to evaporators and airflow in a refrigerator. 
     A known refrigerator typically includes at least one evaporator and one or more plenums to circulate air chilled by an evaporator in a compartment of the refrigerator. The evaporator is connected to a compressor to circulate a cooling medium between a condenser and the evaporator. The refrigerator often contains a freezer compartment, a fresh food compartment or both. The freezer compartment is used to store food and other items at temperatures below zero degrees Celsius while the fresh food compartment is used to store foods and other items at temperatures above zero degrees Celsius. 
     In one type of known refrigerator, a freezer compartment is located above a fresh food compartment. In this configuration, a single evaporator is used and a baffle is placed in a plenum operatively connecting the freezer compartment and the fresh food compartment of the refrigerator. The single evaporator is used to cool the freezer compartment with chilled air to the desired temperature. The baffle is used to control the flow of chilled air to the fresh food compartment to maintain the desired temperature in that compartment. This may be chilled air directed from the freezer compartment, chilled air directed from the evaporator, or a combination. 
     Another type of known refrigerator is a so-called side-by-side refrigerator that includes a freezer compartment disposed to the side of a fresh food compartment.  FIG. 1  is a front perspective view of such a side-by-side refrigerator  200 , which may include a fresh food compartment (shown in  FIG. 4  as  201 ) having an interior volume that is cooled to a temperature greater than a standard freezing point temperature of water (e.g., greater than 0 degrees Celsius). The refrigerator  200  also may include a freezer compartment (shown in  FIG. 4  as  203 ) having an interior volume that is cooled to a temperature equal to or less than the standard freezing point temperature of water. Doors  205  and  208  are used to permit and impede or prevent access to the interior volume of the fresh food and/or freezer compartments, respectively. In this design, often two evaporators, one in each compartment, are used to permit individual control of the temperature in each of the controlled compartments.  FIG. 2  is a side cross-sectional view of a chilled air system of a freezer compartment of a refrigerator of  FIG. 1 . Specifically, as shown in  FIG. 2 , a freezer compartment  303  of the side-by-side refrigerator includes baskets  320  and shelves  322  for holding food items. Air flow  302  is created by fan  304 , which draws air from the bottom of the compartment  303  at  306  and into a plenum  324  running to the upper part of the compartment  303 . The air is drawn over or through evaporator  308  chilling and dehumidifying the air. The chilled air is then returned to freezer compartment  303  at outlet  307  where some of the chilled air is diverted over icemaker  312  or ice reservoir  316 . The rest of the chilled air is returned directly to the freezer compartment  303 . The removal of air from the bottom of freezer compartment  303  at  306  and return of chilled air at the top of freezer compartment  303  at outlet  307  creates a generally circular flow  310  encompassing the entire cavity of the freezer compartment  303 . This method decreases the temperature gradient within the freezer compartment  303  by discharging chilled air at the top of the compartment to mix with the warmer air. However, this design has not eliminated temperature gradients because obstructions to the circulation of air in the compartment exist and because this design still allows the settling of air during non-cooling periods. Further, when utilized in the fresh food compartment, insulation is needed around the plenum to prevent condensation buildup due to the temperature differential between the cold air in the plenum prior to discharge and the warmer air at the top of the compartment, which may cause frost buildup around the opening of the plenum. 
     This design also requires the air to travel most of the height of the compartment within the confines of the plenum as the air flows around, through or over the evaporator. To provide the airflow volume necessary to maintain the chilled temperature in the compartment this design requires considerable system pressure and the evaporator must be doubled over to ensure sufficient channels of flow. This reduces the useful volume of the compartment. Further, a larger fan motor is necessary to maintain the higher system pressure due to the distance traveled by the air in the plenum. Using a larger fan motor creates more noise and is less efficient than using a smaller fan motor. 
     BRIEF DESCRIPTION OF THE INVENTION 
     As described herein, embodiments of the invention overcome one or more of the above or other disadvantages known in the art. 
     In an embodiment of the invention, a refrigerator includes a first storage compartment defining a first interior volume. A first evaporator is configured to cool air that flows past. A first plenum includes a first air outlet, a second air outlet and a first air inlet disposed between the first and second air outlets. The first air inlet is configured to receive air into the first plenum from the first interior volume. The first plenum is configured to flow the air received in the first air inlet over the first evaporator to cool the air. The first and second air outlets are configured to flow the cool air from the first plenum into the first interior volume. 
     In another embodiment, a refrigerator includes a storage compartment defining an interior volume. A first means is used for cooling air. A means is used for distributing air. The means for distributing air is configured to receive air through an inlet, to flow the air received through the inlet over the means for cooling to cool the air, and to flow the cool air into the interior volume through a first outlet and a second outlet. The inlet is disposed between the first and second outlets. 
     In another embodiment, a method for cooling an interior volume of a storage compartment of a refrigerator includes receiving air into an inlet of a plenum. The air received through the inlet is cooled. The cool air is delivered into the interior volume through a first outlet and a second outlet of the plenum. The first inlet is disposed between the first and second outlets. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The following figures illustrate examples of embodiments of the invention. The figures are described in detail below. 
         FIG. 1  is a front perspective view of a known side-by-side refrigerator. 
         FIG. 2  is a side cross-sectional view of a chilled air system of a freezer compartment of the refrigerator of  FIG. 1 . 
         FIG. 3  is a side cross-sectional view of a chilled air system of a freezer compartment of a refrigerator contemplated by the present invention. 
         FIG. 4  is a frontal view of one of the embodiments of the evaporators of the refrigerator of  FIG. 3 . 
         FIG. 5  is a frontal view of another configuration of the evaporators of the refrigerator of  FIG. 3 . 
         FIG. 6  is a side cross-sectional view depicting the airflow of a fresh food compartment of a refrigerator based on the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the invention are described below, with reference to the figures. Throughout the figures, like reference numbers indicate the same or similar components. References to preferred embodiments are for illustration and understanding, and should not be taken as limiting. 
     In an embodiment, the fluid circulation system of the invention circulates air in a compartment of a side-by-side refrigerator. It is contemplated that a chilled air circulation system  100  is disposed in a refrigerator  200  containing a vertically configured compartment where the height of the compartment is greater then the width or depth. As discussed above,  FIG. 1  is a front perspective view of the refrigerator  200  that includes the fresh food compartment  201  and the freezer compartment  203 . The doors  205  and  208  permit and impede or prevent access to the interior volume of the fresh food and/or freezer compartments  201  and  203 . At least one chilled air system is used to cool the fresh food and/or freezer compartments  201  and  203  of the refrigerator  200 , based on chilled air circulation system  100 . 
     As shown in the figures, the refrigerator  200  is a so-called side-by-side refrigerator where the freezer compartment  203  is disposed to the side of the fresh food compartment  201 . Each compartment extends from a bottom  202  to a top  204  and is surrounded by sides  206  and  207 . Further, mullion  209  is situated between the freezer compartment  203  and the fresh food compartment  201 . It is understood, however, that the air circulation system  100  is not limited to use in any particular refrigerator or one particular compartment, but rather can be disposed in various refrigerators in which the fresh food and freezer compartments  201  and  203  are disposed in a variety of positions relative to one another. It is further understood that the refrigerator in which the air circulation system  100  is disposed is not required to have one or only one of each of the fresh food and freezer compartments  201  and  203 , but rather can include none, or one or more of each of the fresh food and freezer compartments  201  and  203 . By way of non-limiting examples, the air circulation system  100  can be disposed in a refrigerator that includes one or more fresh food compartments  201  and no freezer compartment  203 , or that includes one or more freezer compartments  203  and no fresh food compartment  201 . Still further, it is understood that the air circulation system  100  is not limited to use in a refrigerator, but rather can be disposed in various environments where one or more advantages of the air circulation system  100  are provided. 
       FIG. 3  shows one embodiment of the present invention where the freezer compartment  203  is defined by the top  204 , the bottom  202 , the side wall  207 , a back wall  210  and the door  208 . Although not shown in the figure, the freezer compartment is also defined by the mullion  209 . By this arrangement, the freezer compartment  203  is separated from the fresh food compartment  201 . Within or adjacent the back wall  210  is the air circulation system  100 . The air circulation system  100  includes a fan  110 , an evaporator  112  and a plenum having at least two parts, an upper part  114  and a lower part  115 . Air flowing through the upper part  114  and the lower part  115  discharges into the compartment  203  to cause two counter rotating air circulation patterns. Between the upper part  114  and the lower part  115 , the fan  110  is located. The evaporator  112  is disposed in the plenum such that a portion of the evaporator  112  is within the plenum upper part  114 , and such that another portion of the evaporator  112  is in the plenum lower portion  115 . According to an embodiment of the present invention, air  400  is drawn from the freezer compartment  203  into the plenum by the fan  110 , which can be located at approximately mid-height of the freezer compartment  203 . This height may vary based on desired operational characteristics of the compartment. Where an ice bucket  214  is supplied in the compartment as indicated in  FIG. 3  the fan  110  may be located above the mid-height of the compartment at an inlet  118 , thereby providing more airflow to the icemaker. Once drawn into the plenum the air  400  moves to both the upper plenum portion  114  as air  402  and the lower plenum portion  115  as air  408 . Air  402  in the upper plenum portion  114  moves around, through or over an upper portion of evaporator  112  thereby becoming chilled. Air  402  reenters freezer compartment  203  at outlet  116  as air  404 . Air  404  flows along the top  204  and the door  208 , and returns as air  400 . A portion of the air  404  may be diverted as air  406  to an icemaker  312  to freeze water to form ice. The air  406  then flows through ice bucket  214  before rejoining air  404  at the door  208 . Air  408  in the lower plenum portion  115  moves around, through or over a lower portion of the evaporator  112 , thereby becoming chilled and reenters the freezer compartment  203  at  117  as air  410 . Air  410  flows along the bottom  202  and up along the door  208  before returning to air  400 . 
     In one embodiment, the evaporator  112  may contain multiple sections that are joined or are independent. As shown in  FIG. 4  the single evaporator  112  may have an upper section  126  and lower section  124  which are denser than a center section  122 . The fan  110  is located adjacent to center section  122 . The center section  122  is left less dense to accommodate a level of frosting during normal operation without decreasing the flow of air in the air circulation system  100 . 
     In another embodiment, the evaporator  112  may consist of several independent sections, as shown in  FIG. 5 . An upper section  128  and a lower section  130  are each separately controlled by a valve for independent operation and to permit setting a different cooling temperature for each. A third center section  129  of less coil density may be included to dehumidify the air prior to contact with the upper section  128  or the lower section  130  to prevent frosting and a reduction of air flow in plenums  114  and  115 , respectively. 
     While the invention has been described in relation to a freezing compartment  203  for the side-by-side refrigerator  200 , it can be adapted for use in the fresh food compartment  201  of the refrigerator  200 , as indicated by  FIG. 6 . Air  411  is drawn from the fresh food compartment by a fan  140  at inlet  148 . A portion of the air then enters a plenum  144  as air  412  while another portion enters a plenum  145  as air  418 . The air  412  contacts an evaporator (or an upper part of evaporator)  128 , becomes chilled, and is released back into the fresh food compartment  201  through air outlet  146  as chilled air  414 . The chilled air  414  moves down the front of the fresh food compartment  201  and joins air  420  to become air  411 . The air  418  contacts an evaporator (or a lower part of evaporator)  130 , becomes chilled, and is released back into the fresh food compartment  201  through air outlet  147  as air  420 . The air  420  moves up the front of the fresh food compartment  201  and joins the air  412  to become the air  411 . The cycle is then repeated. 
     In an embodiment, a refrigerator has a storage compartment with an interior volume. The storage compartment may be a fresh food compartment or a freezer compartment. A desired temperature is maintained by drawing air from the storage compartment through an inlet to a plenum, pipe, duct or other suitable transmission device. The air inlet is configured, in specific embodiments, at the about midpoint of the plenum. At either end of the plenum may be one or more air outlets. Further, an air outlet at one end of the plenum is configured above the air inlet and a second air outlet at the opposite end of the plenum is configured below the air inlet. Movement of the air from the compartment to the plenum is accomplished, in certain embodiments, by use of a fan or similar device positioned at or adjacent the air inlet and/or at or adjacent one or both of the air outlets, creating a pressure within the plenum. Air entering the plenum travels past an evaporator and becomes cooled. The cooled air is then returned to the storage compartment through the air outlets. The air expelled from the upper air outlet causes the air to travel along the top of the compartment and then down the front of the compartment. The air expelled from the lower air outlet travels along the bottom of the compartment and then up the front of the compartment. The streams from the bottom air outlet and the upper air outlet meet in the front and replace air drawn into the air inlet. A series of vented openings, such vents or louvers, may be used at either or both of the upper or lower air outlet to distribute air across the width and height of the compartment. The evaporator may be divided into several separate sections with each section positioned between the air inlet and either the upper air outlet or the lower air outlet. By dividing the evaporator, different levels of cooling may be provided in the upper or lower airflows. This configuration may be beneficial where additional cooling is required in the upper or lower portion of the compartment. 
     In another embodiment, an interior volume of a storage compartment of a refrigerator is cooled by receiving air into an inlet of a plenum, cooling the air and delivering the cool air back into the interior volume through an upper outlet and a lower outlet of the plenum. The inlet for receiving air into the plenum is disposed between the upper and lower outlet for delivering air back into the compartment. A fan located at the air inlet draws air from the compartment into the plenum. The air becomes cooled by flowing over an evaporator within the plenum. The air expelled from the upper air outlet causes the air to travel along the top of the compartment and then down the front of the compartment. The air expelled from the lower air outlet travels along the bottom of the compartment and then up the front of the compartment. The streams from the bottom air outlet and the upper air outlet meet in the front and replace air drawn into the air inlet. A series of vented openings, such as vents or louvers, may be used at either or both of the upper or lower air outlets to distribute air across the width and/or height of the compartment. The evaporator may be divided into several separate sections with each section positioned between the air inlet and either the upper air outlet or the lower air outlet. By dividing the evaporator, different levels of cooling may be provided in the upper or lower airflows. This configuration may be beneficial where additional cooling is required in the upper or lower portion of the compartment. 
     This written description uses examples to disclose embodiments of the invention, including the best mode, and to enable a person of ordinary skill in the art to make and use embodiments of the invention. It is understood that the patentable scope of embodiments of the invention is defined by the claims, and can include additional components occurring to those skilled in the art. Such other components and examples are understood to be within the scope of the claims.