Patent Publication Number: US-2016231044-A1

Title: Refrigerator having circulation guiding structure enabling an improved thermal distribution profile

Description:
The present invention relates to a refrigerator having an improved and more evenly distributed thermal profile in respect of different shelves along the height of the cooling compartment of the refrigerator. 
     It is well-known that in some refrigerators for instance in cooler type larders, the cooling process is performed by means of an evaporator known as cold wall evaporator. In this configuration, the evaporator is disposed at the back surface of the compartment wall to be cooled. Preserved food items are cooled in the cooling compartment by way of passing the ambient air over the evaporator by means of a fan and accordingly circulating the same inside the compartment. The surface temperature of the evaporator eventually causes frost of the humidity contained in the circulating air in the form of ice accumulations so that defrosting cycles are effected at certain intervals typically by means of electric heaters such that the ice deposited on the cold evaporator surface caused by frozen water content of the circulated air is removed. 
     The refrigerator comprises an evaporator which is placed behind an evaporator cover defining the rear wall of the device&#39;s inner compartment. The evaporator typically effects cooling of the food items by means of the refrigerant circulated by the compressor cooling the ambient air around the evaporator and the cooled air being circulated inside the cooling compartment by a fan. 
     It is to be noted that a plurality of shelves disposed along the height of the inner compartment is needed to be maintained at a temperature whose deviation from a standard value for different shelves is within a limited range. It is therefore desirable to continuously circulate the cooled air in the cooling compartment by means of the fan, which would in turn disrupt energy consumption profile of the household appliance. It is therefore desirable to design an improved inner circulation structure to enhance cooling performance obtainable from the circulation effected by the fan so that the fan itself can be operated in an interrupted manner in intervals. To this end, the present invention provides an advantageous circulation guiding structure by which the temperature difference between the uppermost and the lowermost regions of the cooling compartment can be maintained within a limited range of variation without having to continuously operate the circulation fan. 
     Among others, a prior art patent publication relevant to the technical field of the present invention can be referred to as KR20030018840, disclosing a supply duct formed on one side of a rear side of a refrigerator compartment to supply air introduced from a freezer compartment. A ceiling duct is formed on a ceiling of the refrigerator compartment frontward from the supply duct and a ceiling discharge port formed on a front end of the ceiling duct to discharge chilled air supplied to a lower side of the refrigerator compartment. 
     The present invention, on the other hand, proposes an improved circulation guiding structure providing uniform distribution of temperature in cases where an interrupted fan operation is effected as provided by the characterizing features defined in Claim  1 . 
     Primary object of the present invention is to provide an improved and more evenly distributed thermal profile in respect of different shelves along the height of the cooling compartment of a refrigerator without having to continuously operate the circulation fan. 
     The present invention proposes a refrigerator having a refrigeration compartment comprising a compressor, an evaporator fan and a cold-wall evaporator extending over the interior rear wall of the refrigeration compartment. An air supply interspace is provided between the interior rear wall and an air supply covering. Said air supply interspace is longitudinally divided into three divisions by means of air separators such that a central interspace communicates with two lateral interspaces only at the lower end of the air supply interspace. 
     Said evaporator fan is a radial fan on the inner surface of the ceiling in the refrigeration compartment. The evaporator fan only communicates with the central interspace. 
     The cold-wall evaporator&#39;s cooler inlet side and subsequent sections are arranged to extend along the lateral interspaces and the relatively hot end sections along the central interspace. The air supply covering has a plurality of cooling openings along its vertical longitudinal surface such that cool air is supplied to respective shelves. 
     The central interspace is delimited by the central longitudinal part of the air supply covering that is free of openings between longitudinal ends thereof such that air is maintained in the central interspace during its circulation therethrough. 
     The cooling openings along the lateral interspaces gradually increase in the direction of the ceiling of the refrigeration compartment so that cooler air is supplied to the upper shelves. 
     Accompanying drawings are given solely for the purpose of exemplifying a refrigerator whose advantages over prior art were outlined above and will be explained in brief hereinafter. 
    
    
     
       The drawings are not meant to delimit the scope of protection as identified in the claims nor should they be referred to alone in an effort to interpret the scope identified in said claims without recourse to the technical disclosure in the description of the present invention. 
         FIG. 1  demonstrates a lateral cross-sectional view of the refrigerator exposing the interior of the refrigeration compartment according to the present invention. 
         FIG. 2  demonstrates a front view of the air supply covering disposed against the cold-wall evaporator according to the present invention. 
         FIG. 3  demonstrates a rear view of the air supply covering disposed against the cold-wall evaporator according to the present invention. 
         FIG. 4  demonstrates a general front view of the cold-wall evaporator according to the present invention. 
     
    
    
     The following numerals are used in the detailed description: 
       1 . Refrigerator 
       2 . Door 
       3 . Compressor 
       4 . Condenser 
       5 . Cold-wall evaporator 
       6 . Evaporator fan 
       7 . Air supply interspace 
       8 . Water discharge line 
       9 . Defrost receptacle 
       10 . Vegetable division 
       11 . Refrigeration compartment 
       12 . Air supply covering 
       13 . Shelf 
       14 . Cooling opening 
       15 . Fan covering 
       16 . Air separator 
       17 . Central interspace 
       18 . Lateral interspace 
     The present invention proposes a refrigerator ( 1 ) having a cooling or refrigeration compartment ( 11 ) for preserving foodstuff, a compressor ( 3 ) circulating a refrigerant fluid, a condenser ( 4 ) providing the refrigerant fluid to be condensed, a cold-wall evaporator ( 5 ) effecting refrigeration by absorbing the ambient thermal energy and an evaporator fan ( 6 ) carrying out the circulation of the cooled air. A water discharge line ( 8 ) is provided together with a defrost receptacle ( 9 ) for use during removal of the ice deposited on the cold evaporator surface caused by frozen water content of the circulated air. Said evaporator fan ( 6 ) is disposed on an inner surface portion of the ceiling of the refrigeration compartment ( 11 ) behind a fan covering ( 15 ). 
     A cooling air supply covering ( 12 ) is vertically mounted to the front part of the cold-wall evaporator ( 5 ) parallel to the vertical surface of the cabin&#39;s rear inner wall. The air supply covering ( 12 ) has a plurality of cooling openings ( 14 ) in communication with the refrigeration compartment ( 11 ). An air supply interspace ( 7 ) is accordingly formed throughout said cold-wall evaporator ( 5 ) between the rear wall and the air supply covering ( 12 ) to be delimited by the latter. The cold-wall evaporator ( 5 ) is hence situated behind said air supply covering ( 12 ) in the air supply interspace ( 7 ) through which the cold air is circulated and blown around the refrigeration compartment ( 11 ) with the evaporator fan ( 6 ) motor. 
     In a nutshell, according to the present invention a refrigerator ( 1 ) having a refrigeration compartment ( 11 ) accessible by a door ( 2 ) and in which food items to be preserved are stored, is provided. The cold-wall evaporator ( 5 ) is disposed against the inner surface of the rear wall of the refrigeration compartment ( 11 ) facing the door ( 2 ). 
     The air supply interspace ( 7 ) is longitudinally divided into a plurality of parts by means of air separators ( 16 ) such that a central interspace ( 17 ) communicates with two lateral interspaces ( 18 ) only at a bottom end of the air supply interspace ( 7 ). The evaporator fan ( 6 ) being disposed on an inner surface portion of the ceiling of the refrigeration compartment ( 11 ) and only in communication with the central interspace ( 17 ) provides that the refrigeration compartment&#39;s ( 11 ) relatively high temperature air is sucked and circulated into the central interspace ( 17 ). As is demonstrated in  FIG. 1 , relatively hot air (shown by arrows h), is sucked into the air supply interspace ( 7 ) and as can be seen from  FIG. 3 , is forced downwards through the central interspace ( 17 ). 
     According to the present invention, as shown in  FIG. 4 , the cold-wall evaporator ( 5 ) is configured such that the inlet side (A, C) thereof is first laid substantially along a first lateral interspace ( 18 ), then substantially along a second lateral interspace ( 18 ). Its outlet side (B) is finally laid along the central interspace ( 17 ). To this end, the cold-wall evaporator ( 5 ) is designed to have tubular sections extending substantially in parallel with the longitudinal axes of said central and lateral interspaces ( 17 ,  18 ). Therefore, the inlet side and successive parts (A and C) near the inlet side of the cold-wall evaporator ( 5 ) substantially extending in the lateral interspaces ( 18 ) and the sections near the outlet (B) substantially extending in the central interspace ( 17 ), relatively high temperature air introduced into the central interspace ( 17 ) is cooled by the higher temperature sections of the cold-wall evaporator ( 5 ) near the outlet side (B) thereof since the inlet refrigerant temperature of the cold-wall evaporator ( 5 ) is lower than its outlet refrigerant temperature. This ensures a smaller ΔT so as obtain a more efficient heat transfer. 
     The central interspace ( 17 ) communicating with two lateral interspaces ( 18 ) only at a bottom end of the air supply interspace ( 7 ) ensures that sucked air is gradually cooled by being circulated around the gradually cooler sections of the cold-wall evaporator ( 5 ) while moving towards the bottom and then dividing into the lateral interspaces ( 18 ) and flowing in the direction of the ceiling of the refrigeration compartment ( 11 ). 
     While flowing up in the lateral interspaces ( 18 ), sucked air contacts the cooler sections (A, C) of the cold-wall evaporator ( 5 ) towards its inlet section. The air supply covering ( 12 ) comprises a plurality of cooling openings ( 14 ) positioned between longitudinal ends of the air supply covering ( 12 ) and establishing communication between the lateral interspaces ( 18 ) and the refrigeration compartment ( 11 ). The sizes of the cooling openings ( 14 ) along the lateral interspaces ( 18 ) gradually increase in the direction of the ceiling of the refrigeration compartment ( 11 ) from the bottom part thereof. the central interspace ( 18 ) is delimited by part of the air supply covering ( 12 ) that is free of openings between longitudinal ends of the air supply covering ( 12 ). 
     Therefore, the shelves ( 13 ) of the refrigeration compartment ( 11 ) are fed with cooler air through the cooling openings ( 14 ) such that the temperature difference between the upper shelves ( 13 ) and the lower shelves ( 13 ) is kept minimal. The present invention therefore ensures that the air fed to the upper shelves ( 13 ) by said cooling openings ( 14 ) is cooler due to the special configuration of the air guiding structure. This effect is even more enhanced by the special design of the cold-wall evaporator ( 5 ).