Patent Publication Number: US-2022235993-A1

Title: Induction heating apparatus and method for controlling induction heating apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korean Patent Application No. 10-2021-0028655, filed in Korea Mar. 4, 2021, the entire contents of which is incorporated herein for all purposes by this reference. 
     BACKGROUND 
     1. Field 
     The present disclosure relates to a refrigerator in which a supply duct configured to guide the flow of cold air from one storage compartment to another storage compartment and a damper for opening and closing the supply duct can be prevented from freezing. 
     2. Background 
     Generally, a refrigerator is a home appliance that is provided to store various foods for a long time with cold air generated by using the circulation of a refrigerant according to a refrigeration cycle. 
     In such a refrigerator, to freeze and store items to be stored, one storage compartment is provided, or a plurality of storage compartments are provided by being partitioned from each other. The storage compartment may include a freezer compartment for freezing and storing items to be stored, and a refrigerating compartment for refrigerating and storing the items, wherein the freezer compartment may include at least two freezer compartments or the refrigerating compartment may include at least two refrigerating compartments. 
     The freezer compartment and the refrigerating compartment may be configured to be partitioned vertically or horizontally with a partition wall placed therebetween. For example, in the case of a double door refrigerator, a freezer compartment at a first side and a refrigerating compartment at a second side are partitioned from each other with a partition wall placed therebetween. 
     In addition, the refrigerating compartment and the freezer compartment receive cold air generated by a refrigeration system and is controlled to maintain a temperature range between an upper limit reference temperature NT+Diff and a lower limit reference temperature NT−Diff relative to a preset reference temperature NT;Noth. For example, when a storage compartment has temperature higher than the upper limit reference temperature, a compressor is operated to supply cold air to the associated storage compartment, but when the storage compartment has temperature lower than the lower limit reference temperature, the operation of the compressor is stopped to cut off the cold air supplied into the associated storage compartment. 
     Particularly, in the case of a refrigerator that uses one evaporator to control the temperature of the refrigerating compartment and the freezer compartment, a cold air duct configured to guide the selective supply of at least some of cold air supplied to the freezer compartment (or the refrigerating compartment) to the refrigerating compartment (or the freezer compartment) is provided and is configured to be opened/closed by the damper. 
     That is, due to the opening or closing of the cold air duct by the damper, at least some of cold air passing through the evaporator can be supplied selectively to the freezer compartment or the refrigerating compartment. 
     Meanwhile, the damper exists in a storage compartment with high humidity and thus may freeze. Accordingly, in conventional technologies, various structures for preventing the freezing of the damper are provided. 
     For example, in a prior art disclosed in (Patent Document 1) Korean Patent Application Publication No. 10-1999-0009712, a heater is provided between two baffles, and when the closing of a refrigerator door is detected, the heater generates heat for a preset period of time to prevent the freezing of a damper. 
     However, in the prior art disclosed in (Patent Document 1), due to the heater, the damper and the surrounding area of the baffles are effectively prevented from freezing, but the freezing of a duct located at a side opposite to the damper still occurs. 
     Furthermore, in the prior art disclosed in (Patent Document 1), the heater is configured to operate only by opening and closing a refrigerator door, so when there is no opening or closing of the refrigerator door for a long time, there is a problem that the heater does not operate for a long time, which may cause freezing in the associated parts. 
     In addition, in a prior air disclosed in (Patent Document 2) Korean Patent Application Publication No. 10-2001-0056077, a cold air introduction hole is formed in a control box located inside a refrigerating compartment, so the space of the refrigerating compartment is reduced as much as the space of the associated control box. Particularly, in the case of the refrigerating compartment, when the heater generates heat, the surrounding temperature of the refrigerating compartment easily rises, which inevitably affects the refrigeration of the refrigerating compartment. 
     Accordingly, recently, a structure in which a damper is located in a freezer compartment and the installed portion of the damper and the refrigerating compartment are connected to each other by a flow duct so as to transfer cold air therebetween is provided. This is disclosed in (Patent Document 3) Korean Patent Application Publication No. 10-2020-0095887, and (Patent Document 4) Korean Patent Application Publication No. 10-2020-0107390. 
     In the prior arts disclosed in (Patent Document 3) and (Patent Document 4), the damper provided to maintain temperature difference generated between the refrigerating compartment and a refrigerating compartment duct is disposed in the freezer compartment, so the reduction of the space of the refrigerating compartment in the prior art disclosed in (Patent Document 2) is prevented. 
     However, in the prior arts disclosed in (Patent Document 3) and (Patent Document 4), freezing occurs in a connection portion between a damper housing (a first unit) provided to install the damper of a freezer compartment duct (a freezer grille assembly) and a supply duct (a second unit) connecting the damper housing with the refrigerating compartment duct (a refrigerating compartment grille assembly). 
     That is, the flow path of the supply duct is most preferably configured to completely correspond to the flow path of the damper housing, but in consideration that there may be a coupling error during assembly, normally, the inlet flow path of the supply duct is designed to be configured larger than the outlet flow path of the damper housing. 
     Accordingly, frost or dew generated during the discharge of cold air to the supply duct from the damper freezes in the flow path inlet of the supply duct (specifically, a stepped portion at the coupling portion of the supply duct with the damper housing). 
     Particularly, in the prior arts disclosed in (Patent Document 3) and (Patent Document 4) described above, even if ice is formed in the flow path inlet of the supply duct, it is difficult to remove the ice. Accordingly, as the frost frozen in the flow path inlet of the supply duct increases in size, flow resistance increases, and in the worst case, the associated flow path may be closed. 
     Of course, in the prior arts disclosed in (Patent Document 3) and (Patent Document 4), the ice may be defrosted by forcibly raising the temperature of the refrigerating compartment, or the ice may be defrosted by periodically (or intermittently) performing operation control for defrosting in the supply duct. 
     However, defrost water generated during the defrosting flows down on the wall surface of the inside of the supply duct, and flows down to the connection portion of the supply duct with the damper housing, and collects in a portion at which the damper is located. Accordingly, there is an additional problem that the defrost water freezes during the operation of the refrigerator and causes the malfunction of the damper. 
     DOCUMENTS OF RELATED ART 
     
         
         (Patent Document 1) Korean Patent Application Publication No. 10-1999-0009712 
         (Patent Document 2) Korean Patent Application Publication No. 10-2001-0056077 
         (Patent Document 3) Korean Patent Application Publication No. 10-2020-0095887 
         (Patent Document 4) Korean Patent Application Publication No. 10-2020-0107390 
       
    
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, and wherein: 
         FIG. 1  is a perspective view of the exterior of a refrigerator according to an embodiment of the present disclosure; 
         FIG. 2  is a front view illustrating the state of the exterior of the refrigerator according to the embodiment of the present disclosure; 
         FIG. 3  is a front view illustrating the state of the inside of the refrigerator according to the embodiment of the present disclosure; 
         FIG. 4  is a view illustrating the structure and combined relation of each grille assembly, a damper assembly, and a supply duct of the refrigerator according to the embodiment of the present disclosure; 
         FIG. 5  is a rear view of each of the grille assemblies of the refrigerator according to the embodiment of the present disclosure; 
         FIG. 6  is a view illustrating a state in which the supply duct is mounted to each of the grille assemblies of the refrigerator according to the embodiment of the present disclosure; 
         FIG. 7  is a view illustrating the structures of the supply duct and a second heater mounted to the supply duct in the refrigerator according to the embodiment of the present disclosure; 
         FIG. 8  is a sectional view illustrating the structures of the supply duct and the second heater mounted to the supply duct in the refrigerator according to the embodiment of the present disclosure; 
         FIG. 9  is an enlarged view illustrating the states of a second grille assembly and the supply duct when a step occurs therebetween; 
         FIG. 10  is an enlarged view of an “A” part of  FIG. 8  illustrating a reverse step structure between the second grille assembly and the supply duct; 
         FIG. 11  is a planar sectional view illustrating the installed state of the supply duct of the refrigerator according to the embodiment of the present disclosure; 
         FIG. 12  is an enlarged view of a “B” part of  FIG. 11 ; 
         FIG. 13  is a perspective view illustrating the installed state of the supply duct of the refrigerator according to the embodiment of the present disclosure; 
         FIG. 14  is an exploded perspective view of the supply duct of the refrigerator according to the embodiment of the present disclosure viewed from the front of the supply duct; 
         FIG. 15  is an exploded perspective view of the supply duct of the refrigerator according to the embodiment of the present disclosure viewed from the rear of the supply duct; 
         FIG. 16  is a combined perspective view of the supply duct of the refrigerator according to the embodiment of the present disclosure viewed from the rear of the supply duct; 
         FIG. 17  is a block diagram approximately illustrating a controller of the refrigerator according to the embodiment of the present disclosure; 
         FIG. 18  is a graph illustrating the temperature change of each part of the supply duct when only a first heater is provided in the refrigerator according to the embodiment of the present disclosure; 
         FIG. 19  is a graph illustrating the temperature change of each part of the supply duct when the first heater and the second heater are provided in the refrigerator according to the embodiment of the present disclosure; and 
         FIG. 20  is a view illustrating the state of the supply duct when only a plurality of second heaters is provided in the refrigerator according to the embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, the exemplary embodiment of the refrigerator of the present disclosure will be described with reference to  FIGS. 1 to 20 . 
       FIGS. 1 and 2  illustrate the exterior structure of the refrigerator according to the embodiment of the present disclosure, and  FIG. 3  illustrates the internal structure of the refrigerator according to the embodiment of the present disclosure. 
     In addition,  FIG. 4  is a view illustrating the assembly structure of each grille assembly, a damper assembly, and a supply duct of the refrigerator according to the embodiment of the present disclosure. 
     As illustrated in these drawings, in the refrigerator according to the embodiment of the present disclosure, a first heater  600  may be provided in the damper assembly  500 , and a second heater  700  may be provided in the supply duct  400 . 
     That is, due to the first heater  600 , the damper assembly  500  or the connection portion of the damper assembly  500  with the supply duct  400  may be prevented from freezing, and due to the second heater  700 , the connection portion of the supply duct  400  with the damper assembly  500  or the inside of the supply duct  400  may be prevented from freezing. Accordingly, due to the provision of the first heater  600  and the second heater  700 , the damper assembly  500  may be provided in a second grille assembly  300 , and the damper assembly  500  and the supply duct  400  may be prevented from freezing. 
     Hereinafter, each component of such a refrigerator according to the embodiment of the present disclosure will be described more in detail. 
     First, the refrigerator according to the embodiment of the present disclosure may include a refrigerator body  100 . 
     As illustrated in  FIG. 3 , the refrigerator body  100  may include an outer casing  110  constituting the outer body of the refrigerator body  100  and inner casings  120  and  130  located in the outer casing  110 . 
     Here, the inner casings  120  and  130  may include a plurality of inner casings, wherein the inner casings may be configured to form storage compartments  121  and  131 , respectively. That is, the inner casings  120  and  130  may be configured as box bodies open forward and may have the storage compartments  121  and  131  formed respectively therein so as to store items therein. 
     Such a refrigerator body  100  may be configured to have a first storage compartment  121  at a first side of a partition wall  140  and to have a second storage compartment  131  at a second side thereof, between the partition wall  140  placed between the first storage compartment  121  and the second storage compartment  131 . That is, a first inner casing  120  which provides the first storage compartment  121  and a second inner casing  130  which provides the second storage compartment  131  may be provided at the first and second sides, respectively, with the partition wall  140  placed between the first inner casing  120  and the second inner casing  130 . 
     The two inner casings  120  and  130  may be provided respectively at the left and right sides of the refrigerator body  100 , and may be provided respectively at the upper and lower sides of the refrigerator body  100 . In the embodiment of the present disclosure, when the refrigerator body  100  is viewed from the front side, the first storage compartment  121  of the first inner casing  120  is located at the right side, and the second storage compartment  131  of the second inner casing  130  is located at the left side. 
     Furthermore, the second storage compartment  131  may maintain temperature lower than the temperature of the first storage compartment  121 . For example, the second storage compartment  131  may be a freezer compartment maintained at temperature below 0° C., and the first storage compartment  121  may be a refrigerating compartment maintained at temperature greater than 0° C. 
     In addition, doors  122  and  132  may be located on the open front surfaces of the inner casings  120  and  130 , respectively, and may selectively open and close the storage compartments  121  and  131 , respectively. In this case, each of the doors  122  and  132  may be a swinging door or drawer-type door. 
     Next, the refrigerator according to the embodiment of the present disclosure may include a first grille assembly  200 . 
     The first grille assembly  200  may be located at the rear of the inside of the first inner casing  120 , and may function to guide the flow of cold air supplied into the first storage compartment  121 . 
     As illustrated in  FIG. 4 , the first grille assembly  200  may include a first grille panel  210  located to be exposed to the inside of the first storage compartment  121  and a first duct plate  220  coupled to the rear of the first grille panel  210 . 
     Here, a plurality of first cold air discharge holes  211  may be formed in the first grille panel  210  so as to discharge cold air to the first storage compartment  121 , and a cold air flow path  221  may be formed in the first duct plate  220  so as to supply cold air to each of the first cold air discharge holes  211 . 
     Furthermore, a plurality of first communication holes  222  corresponding to the first cold air discharge holes  211 , respectively, may be formed in the first duct plate  220 , and the cold air flow path  221  may be configured to pass each of the first communication holes  222 . In this case, the cold air flow path  221  may be formed concavely on the rear surface of the first duct plate  220  or may be formed in the first duct plate  220 . 
     In addition, a supply hole  223  through which cold air is supplied from the supply duct  400  may be formed in a side of the rear surface of the first duct plate  220 , and the cold air flow path  221  may be configured to communicate with the supply hole  223 . 
     That is, after cold air transferred to the supply duct  400  is introduced through the supply hole  223  to the cold air flow path  221 , the cold air may flow along the cold air flow path  221  and may flow sequentially through each of the first communication holes  222  and each of the first cold air discharge holes  211 , and may be supplied into the first storage compartment  121 . 
     Next, the refrigerator according to the embodiment of the present disclosure may include the second grille assembly  300 . 
     The second grille assembly  300  may be located at the rear of the inside of the second inner casing  130 , and may function to guide the flow of cold air supplied into the second storage compartment  131 . 
     As illustrated in  FIG. 4 , the second grille assembly  300  may include: a second grille panel  310  located to be exposed to the inside of the second storage compartment  131 , a second duct plate  320  coupled to the rear of the second grille panel  310 , a shroud  330  coupled to the rear of the second duct plate  320 , and a blower fan  340  installed between the second duct plate  320  and the shroud  330 . 
     Here, a plurality of second cold discharge holes  311  may be formed in the second grille panel  310  so as to discharge cold air to the second storage compartment  131 , and the cold air flow path (not shown) may be formed in the second duct plate  320  so as to supply cold air to each of the second cold discharge holes  311 . 
     Furthermore, a plurality of second communication holes  322  corresponding to the second cold discharge holes  311 , respectively, may be formed in the second duct plate  320 , and the cold air flow path may be configured to pass each of the second communication holes  322 . In this case, the cold air flow path may be configured to be recessed from the rear surface of the second duct plate  320  or may be configured in the second duct plate  320 . 
     In addition, a cold air introduction hole  331  through which cold air passing through an evaporator  810  is introduced may be formed in the shroud  330 . 
     In addition, a mounting part  332  for the mounting of the damper assembly  500  may be configured at a side of the shroud  330  facing the first grille assembly  200 . In this case, the mounting part  332  may be formed concavely from the front surface of the shroud  330  (a surface opposite to the second duct plate) to receive the damper assembly  500 . 
     Furthermore, in the side wall surfaces of the shroud  330 , an exposure hole  333  may be formed in the side wall surface of the shroud  330  in which the mounting part  332  is formed, wherein a passing flow path  501  of the damper assembly  500  installed in the mounting part  332  may be exposed to the shroud  330 . 
     Next, the refrigerator according to the embodiment of the present disclosure may include the supply duct  400 . 
     The supply duct  400  may function to supply some of cold air guided by the second grille assembly  300  to the first grille assembly  200 . 
     The supply duct  400  may be configured as a duct having a supply flow path  401  (see  FIGS. 8 to 12 ) formed therein. In this case, the first end of the supply duct  400  may be connected to the first grille assembly  200 , and the second end of the supply duct  400  may be connected to the second grille assembly  300 . 
     Specifically, the first end of the supply duct  400  may be configured to cover the supply hole  223  formed in the rear surface of the first grille assembly  200 , and an outlet  411  (see  FIGS. 13 to 15 ) through which cold air is supplied to the supply hole  223  may be formed in a portion of the supply duct  400  corresponding to the supply hole  223 . In this case, the outlet  411  may be the cold air discharge portion of the supply flow path  401 . 
     In addition, the second end of the supply duct  400  may be configured to cover the exposure hole  333  formed in the side surface of the second grille assembly  300 , and an inlet  412  (see  FIG. 14 ) through which cold air is supplied from the exposure hole  333  may be formed in a portion of the supply duct  400  corresponding to the exposure hole  333 . In this case, the inlet  412  may be the cold air introduction portion of the supply flow path  401 . 
     In addition, the supply duct  400  may be configured as a duct formed with a single member, or may be configured as a duct formed by coupling at least two members to each other. 
     The supply duct  400  according to the embodiment of the present disclosure, for an example, may be formed by coupling a body part  410  to a cover part  420 . 
     Here, the body part  410  may be a part which is located at a side facing each of the two grille assemblies  200  and  300  and has an outer surface formed to be open, and the cover part  420  may be a part configured to cover the open outer surface of the body part  410 . 
     Particularly, the inlet  412  of the supply duct  400  may be formed by coupling the body part  410  to the cover part  420 , and the outlet  411  of the supply duct  400  may be formed in the body part  410 . 
     Meanwhile, each portion of the inside of the supply duct  400  may have different temperature. For example, the connection portion of the supply duct  400  with the second grille assembly  300  may have temperature lower than the temperature of the connection portion of the supply duct  400  with the first grille assembly  200 . 
     In consideration this, in the connection portion of the inner surface of the supply duct  400  with the second grille assembly  300 , condensate water is more likely to be generated due to temperature difference between the inside and outside of the supply duct  400 , and this generated condensate water may flow down along the wall surface of the associated supply duct  400  and may collect and freeze in the lower portion of the inside of the supply duct  400 . 
     Accordingly, in the embodiment of the present disclosure, a guide rib  430  (see  FIGS. 8 and 14 ) may be formed on the inner surface of the supply duct  400  such that condensate water flowing down from the upper surface of the inside of the supply duct  400  flows to the first grille assembly  200  connected to the first end of the supply duct  400 . 
     That is, the condensate water flowing down along the inner wall surface of the supply duct  400  may not collect in the connection portion of the supply duct  400  with the second grille assembly  300 , but may flow down to the first storage compartment  121  which has temperature above zero, so the condensate water may be prevented from freezing. 
     The guide rib  430  may be formed from the inlet  412  to the outlet  411  in the inner surface of the supply duct  400  such that the guide rib  430  is formed to be inclined or rounded downward gradually toward the outlet  411  from the inlet  412 . 
     Particularly, the guide rib  430  is preferably configured to have a protruding height of 1.5 mm to 2.5 mm. That is, when the guide rib  430  protrudes to have the height of less than 1.5 mm, condensate water may directly flow down without being guided by the guide rib, and when the guide rib  430  protrudes to have height higher than 2.5 mm, the resistance of cold air flow in the supply flow path  401  may increase. 
     Next, the refrigerator according to the embodiment of the present disclosure may include the damper assembly  500 . 
     The damper assembly  500  may function to selectively perform or stop the supply of cold air toward the supply duct  400  from the second grille assembly  300 . 
     For example, during the cooling operation of the first storage compartment  121 , the damper assembly  500  may open the supply duct  400  such that cold air introduced into the second grille assembly  300  is supplied to the first storage compartment  121 . During the cooling operation of the second storage compartment  131 , the damper assembly  500  may close the supply duct  400  such that cold air introduced into the second grille assembly  300  is supplied to the second storage compartment  131 . 
     As illustrated in  FIG. 8 , such a damper assembly  500  may include a damper cover  510  and a damper  520 . 
     The damper cover  510  may be a part mounted to the connection portion of the second grille assembly  300  with the supply duct  400 . 
     The damper cover  510  may be formed of an insulating material (for example, Styrofoam). 
     Furthermore, the damper cover  510  may be configured to have an inlet through which cold air is introduced and an outlet through which cold air is discharged, and may have the passing flow path  501  formed therein, the passing flow path communicating the inlet with the outlet. In this case, the inlet of the damper cover  510  may communicate with a part at which the blower fan  340  of the second grille assembly  300  is located, and the outlet of the damper cover  510  may communicate with the inlet  412  of the supply duct  400 . 
     In addition, the damper  520  may be installed in the passing flow path  501  of the damper cover  510 . The damper  520  may be coupled to a damper motor  521  and may be configured to open/close the passing flow path  501  by being rotated due to the operation of the damper motor  521 . 
     Meanwhile, the passing flow path  501  of the damper assembly  500  is most preferably configured to correspond to the supply flow path  401  of the supply duct  400  for cold air flow and freezing prevention. 
     However, when tightly coupling two normal components to each other, due to an assembly tolerance between the two components, the two components may not exactly match each other and a step may occur therebetween. 
     That is, during the coupling of the supply duct  400  to the wall surface of the second grille assembly  300  in which the exposure hole  333  is formed, due to an assembly tolerance therebetween, the supply flow path  401  of the supply duct  400  and the passing flow path  501  of the damper assembly  500  in the exposure hole  333  may not match exactly with each other, but may be partially misaligned from each other. 
     However, when the supply duct  400  is assembled with the passing flow path  501  by being misaligned upward therefrom, a step may be formed between the outer surface of the damper cover  510  of the damper assembly  500  and the upper surface of the inlet of the supply flow path  401 , and condensate water may be frozen in the portion  403  of such a step (see  FIG. 9 ). That is, cold air may not flow to the step portion  403 , so even if dew is formed in the associated portion, this dew may not be removed. 
     In consideration of this, in the embodiment of the present disclosure, a step  402  (see  FIG. 10 ) (hereinafter, referred to as “a reverse step”) with which some of flowing cold air hits is formed in the communication portion of the inlet  412  of the supply flow path  401  with the outlet of the passing flow path  501 . 
     That is, a normal step is generally formed so as not to interfere with the flow of cold air, but as described above, as for such a normal step, condensate water may be frozen in the associated step portion  403 . Accordingly, the reverse step  402  may be formed by protruding a portion of the supply duct  400  to the inside of the passing flow path  501  such that the freezing of the condensate water can be prevented. 
     In this case, the reverse step  402  may be continuously hit by cold air, and the cold air may be dry air in which moisture is removed from the cold air while the cold air passes through the evaporator, so even if condensate water is generated in the associated portion, the cold air may directly hit condensate water and may remove the moisture thereof so as to prevent freezing. 
     Of course, due to the reverse step  402  described above, the flow of cold air introduced into the supply flow path  401  through the passing flow path  501  may be partially interrupted. However, when it is considered that a problem caused by freezing is more serious than the interruption of the cold air flow described above and power consumption required to prevent such freezing is great, even if the loss of cold air flow occurs, preventing the freezing is more preferable. 
     Particularly, the reverse step  402  described above may be configured to be larger than an assembly tolerance, so in the process of assembling the damper assembly  500  or the supply duct  400  with the second grille assembly  300 , even if some misalignment from each other occurs due to the assembly tolerance therebetween, the reverse step  402  may exist in the inlet  412  of the supply flow path  401 . 
     Furthermore, the reverse step  402  is preferably configured to have height formed to be within 5 mm. That is, when the height of the reverse step  402  exceeds 5 mm, the loss of cold air flow may increase rapidly, and flow noise may be loud, but when the reverse step  402  is configured to have height which is within 5 mm, freezing may be sufficiently prevented. 
     In addition, the reverse step  402  may be formed in the entire portion of the outlet of the passing flow path  501 , or only in a portion of the outlet of the passing flow path  501 . 
     However, when it is considered that condensate water does not flow down but collects in the upper portion of each of the outlet of the passing flow path  501  and the inlet  412  of the supply flow path  401  than other portions thereof, the upper portion of the inlet  412  of the supply flow path  401  may be most preferably configured to be located at a position lower than the upper portion of the outlet of the passing flow path  501 . 
     The reverse step  402  may be formed by a size difference between the two flow paths  401  and  501 , or may be formed by the partial misalignment of assembly positions thereof. 
     That is, the inlet  412  of the supply flow path  401  may be configured to be smaller than the outlet of the passing flow path  501 , or the upper portion of the inlet  412  of the supply flow path  401  may be configured to be located at a position lower than the upper portion of the outlet of the passing flow path  501 . 
     Next, the refrigerator according to the embodiment of the present disclosure may include the first heater  600 . 
     The first heater  600  may be a heater provided to prevent the freezing of the damper assembly  500  or the freezing of the connection portion of the damper assembly  500  with the supply duct  400 . 
     As illustrated in  FIGS. 8 and 12 , such a first heater  600  may be provided in the damper assembly  500 . Specifically, the first heater  600  may be provided on the outer surface of the damper  520 . 
     Particularly, the first heater  600  may be located on a surface of the outer surfaces of the damper  520  directed to the supply duct  400  during the closing of the passing flow path  501 . Accordingly, the freezing of the damper  520  may be prevented, and the freezing of the supply flow path  401  formed inside the supply duct  400  may also be prevented due to heat generated by the heating of the first heater  600 . 
     The first heater  600  may be configured as a surface heating body. Accordingly, it is possible to install the first heater  600  on the surface of the damper  520 , and it is possible to evenly heat the entire portion of the damper  520 . 
     Next, the refrigerator according to the embodiment of the present disclosure may include the second heater  700 . 
     The second heater  700  is a heater provided to prevent the freezing of the connection portion of the supply duct  400  with the damper assembly  500  or the freezing of the inside of the supply duct  400 . 
     As illustrated in  FIGS. 12 to 16 , such a second heater  700  may be provided on the outer surface of the supply duct  400 . Specifically, the second heater  700  may be configured as a coil heater and may be installed to be in contact with at least a portion of the outer surface of the supply duct  400  therealong. That is, when it is considered that the maintenance of the heater may be difficult when the heater is provided on the inner surface of the supply duct  400 , the heater may be provided on the outer surface of the supply duct  400  such that the maintenance of the heater is easy and the installation of the heater is performed easily. 
     In the first and second ends of the supply duct  400 , the second heater  700  may be installed to be located to be adjacent more to the connection portion of the supply duct  400  with the damper assembly  500 . That is, when it is considered that condensate water is generated in a place having a large temperature difference, in the outer surface of the supply duct  400 , condensate water is more likely to be generated gradually toward the connection portion of the supply duct  400  with the damper assembly  500 , and is less likely to be generated gradually toward the connection portion of the supply duct  400  with the first grille assembly  200  due to temperature higher than a dew point temperature. In consideration of this, the second heater  700  is preferably located as much as possible at the connection portion of the supply duct  400  with the damper assembly  500 . 
     Particularly, the second heater  700  may be installed to have at least a portion located at an edge formed on the connection portion of the supply duct  400  with the damper assembly  500  in the outer surface of the supply duct  400 . 
     That is, the second heater  700  may be located at a portion at which condensate is most likely to occur such that the condensate generated in the associated portion can be prevented from freezing. Furthermore, the edge is a bent portion, and thus even if a structure for restraining the second heater  700  is not installed on the outer surface of the supply duct  400 , the second heater  700  configured as the coil heater may maintain a precisely installed state thereof. Accordingly, the edge is most preferably the installation position of the second heater  700 . 
     In addition, the second heater  700  may be installed to have at least a portion located on the center portion of the supply duct  400 . That is, when it is considered that condensate water is generated in the center portion of the supply duct  400 , the portion of the second heater  700  may be located in the associated portion such that the condensate water is prevented from freezing in the associated portion. 
     Furthermore, another portion of the second heater  700  is preferably installed along the upper surface of the supply duct  400 . That is, the second heater  700  may be installed to be in more contact with the upper portion of the supply duct  400  than the lower portion of the supply duct  400  such that condensate water generated on the upper surface of the inside of the supply duct  400  can be prevented from freezing. In this case, the portion of the second heater  700  ranging from the edge of a first end of the supply duct  400  to the center portion of the supply duct  400  may be configured to be installed along the upper surface of the supply duct  400 . 
     In addition, the first heater  600  may be configured to have a higher output value than the second heater  700 . That is, the second heater  700  may function to assist the first heater  600  such that power consumption can be reduced as much as possible. 
     Of course, in the refrigerator according to the embodiment of the present disclosure, only the first heater  600  may be provided or only the second heater  700  may be provided. 
     However, when only the first heater  600  is provided, the first heater  600  is required to generate heat with a sufficiently high output so as to prevent the freezing of the inside of the supply duct  400 , so power consumption may be high and may affect the temperature of the second storage compartment  131 . 
     Furthermore, the second heater  700  may be provided on the outer surface of the supply duct  400 , and thus when only the second heater  700  is provided, it may be difficult to effectively prevent the freezing of the damper  520 . Furthermore, to prevent the freezing of the damper  520 , the second heater  700  is required to generate heat with high output. In this case, excessive heat may be unnecessarily supplied to the center portion of the supply duct  400 , so power consumption may be inevitably increased. 
     In consideration of this, it is most advantageous that both the first heater  600  and the second heater  700  are provided for freezing prevention and power consumption reduction. 
     For example, as can be seen from the graph of  FIG. 18 , when only the first heater  600  is provided, the surface temperature of the center portion or first end (the connection portion of the supply duct  400  with the first grille assembly) of the supply duct  400  may be lower than the temperature of the internal space of the supply duct  400 , and thus condensate water is likely to be generated. 
     Furthermore, as can be seen from the graph of  FIG. 19 , when both the first heater  600  and the second heater  700  are provided, the temperature of the internal space of the supply duct  400  and the surface temperature of each portion of the supply duct  400  may be higher than a dew point temperature, so condensate water may be prevented from being generated. 
     In this case, s/duct 1 of each graph described above is the inlet portion (the connection portion of the supply duct  400  with the second grille assembly) of the supply duct  400 ; s/duct 2 is the center portion of the supply duct  400 ; and s/duct 3 is the outlet portion (the connection portion of the supply duct  400  with the first grille assembly) of the supply duct  400 . 
     Meanwhile, when the damper  520  operates to open the passing flow path  501 , the first heater  600  and the second heater  700  may be controlled to stop heating. That is, in a state in which the damper  520  opens the passing flow path, the temperature of cold air of the first grille assembly  200  may not be affected through the supply duct  400 . 
     Furthermore, in a case in which the damper  520  is maintained to close the passing flow path  501 , when room temperature RT is within a first preset temperature range, the first heater  600  and the second heater  700  may be controlled to repeatedly perform and stop heating for a preset period of time. In this case, the first preset temperature range as a normal room temperature range may be the temperature of 12.5&lt;RT≤23.0° C. 
     Additionally, when the room temperature RT is within a second preset temperature range, the first heater  600  and the second heater  700  may be controlled such that the first heater  600  and the second heater  700  are maintained to continue heating. In this case, the second preset temperature range may be the temperature of RT≤12.5° C. lower than the first preset temperature range. That is, when the room temperature is low, the internal temperature of each of the storage compartments may be maintained at an excessively low temperature, and accordingly, each of the heaters  600  and  700  may generate heat to prevent the internal temperature of the storage compartment from decreasing excessively. 
     Additionally, when the room temperature RT is within a third preset temperature range, the first heater  600  and the second heater  700  may be controlled to repeatedly perform and stop heating for a preset period of time. In this case, the third preset temperature range may be the temperature of 23° C.&lt;RT higher than the first preset temperature range. 
     Particularly, heating interruption time when the room temperature RT is within the first preset temperature range may be preset to be shorter than heating interruption time when the room temperature RT is within the third preset temperature range. That is, when the room temperature RT is relatively high, the supply duct  400  may be affected by the room temperature RT conducted through the outer casing  110 , and accordingly, the heating interruption time may be maintained longer to reduce power consumption. 
     Of course, when the first heater  600  and the second heater  700  operate under a special condition during the operation of the refrigerator, at least one heater  600  or  700  may generate heat by control different from the above-described control. 
     For example, during the error occurrence of one sensor related to the defrosting operation in a case in which the refrigerator is initially powered on, or in a case in which the internal temperature of at least one storage compartment  121  or  131  is lower than the lower limit reference temperature NT−Diff, when the indoor humidity is 80% or more, the ice making or separating of at least one ice maker may be included in the special condition. 
     Meanwhile, as illustrated in  FIG. 17 , the refrigerator according to the embodiment of the present disclosure may be configured to be operated by the control of a controller  900 . 
     Here, the controller  900  may control a refrigeration system  800  including the evaporator  810  and a compressor  820  to generate cold air. 
     Furthermore, the controller  900  may check the internal temperatures obtained from temperature sensors  910  and  920  located in the storage compartments  121  and  131 , respectively, and then may control each of the internal temperatures by controlling the operations of the damper  520  and the blower fan  340  on the basis of the checked internal temperatures. 
     Furthermore, the controller  900  may check the internal temperature, the room temperature, and the indoor humidity obtained from the temperature sensor  910  and  920  located in the storage compartments  121  and  131 , respectively, a temperature sensor  930  which measures the room temperature, and a humidity sensor  940  which measures the indoor humidity, and may control the operation of each of the heaters  600  and  700  to prevent the freezing of the damper  520  and the supply duct  400 . 
     Hereinafter, the operation control process of the refrigerator according to the embodiment of the present disclosure described above and the operation of each component of the refrigerator due to such control will be described more in detail. 
     First, when the performance condition of cooling operation (operation for supplying cold air) is satisfied (when the internal temperature of at least one storage compartment belongs to an unsatisfactory temperature), the refrigeration system including the evaporator  810  and the blower fan  340  may operate. 
     In addition, when such cooling operation is performed, the controller  900  which controls the operation of the refrigerator may control the operation of the damper  520  according to the internal temperature of each of the storage compartments  121  and  131 . 
     For example, when the internal temperature of the first storage compartment  121  belongs to the unsatisfactory temperature which is temperature higher than an upper limit reference temperature NT+Diff specified on the basis of the preset reference temperature NT, cold air may be controlled to be supplied to the first storage compartment  121 . 
     Accordingly, in order to supply cold air to the first storage compartment  121 , the damper  520  may be opened such that the passing flow path  501  and the supply flow path  401  are controlled to communicate with each other. Accordingly, cold air passing through the evaporator  810  due to the operation of the blower fan  340  may be introduced to space between the second duct plate  320  and the shroud  330  of the second grille assembly  300 , may continuously pass sequentially through the passing flow path  501  of the damper assembly  500  and the supply flow path  401  of the supply duct  400 , and may be supplied to the first storage compartment  121 . 
     In this case, while the cold air passes sequentially through the passing flow path  501  and the supply flow path  401 , power supply to the first heater  600  and the second heater  700  may be controlled to be cut off. Accordingly, the temperature of the cold air supplied to the first storage compartment  121  may be prevented from increasing unintentionally. 
     Particularly, while the cold air flows through the passing flow path  501  into the supply flow path  401 , some of the flowing cold air may hit the reverse step  402  which exists in the associated portion. Accordingly, even if condensate water exists on the reverse step  402 , the condensate water may be removed by the cold air, so the formation of frost due to condensate water may be prevented. 
     Furthermore, condensate water generated in the supply duct  400  may flow down the wall surface of the inside of the supply duct  400 . In this process, while the condensate water flows along the guide rib  430  formed on the internal wall surface of the supply duct  400 , the condensate water may be transferred to the first storage compartment  121 . In this case, since the first storage compartment  121  is maintained at temperature higher than dew point temperature, the condensate water transferred to the first storage compartment  121  may be prevented from freezing. 
     Additionally, when the internal temperature of the first storage compartment  121  reaches temperature (for example, NT−Diff) in a satisfactory temperature NT±Diff relative to the preset reference temperature NT, cold air supply to the first storage compartment  121  may stop. That is, the damper  520  may be controlled to close the passing flow path  501 . 
     When the internal temperature of the first storage compartment  121  belongs to the satisfactory temperature but the internal temperature of the second storage compartment  131  belongs to the unsatisfactory temperature (temperature exceeding NT+Diff), cold air may be controlled to be supplied to the second storage compartment  131 . 
     Accordingly, when supplying cold air to the second storage compartment  131 , the damper  520  may be controlled to close the passing flow path  501 . Accordingly, cold air passing through the evaporator  810  due to the operation of the blower fan  340  may be introduced to space between the second duct plate  320  and the shroud  330  of the second grille assembly  300 , and then may be supplied through each of the second cold discharge holes  311  of the second grille panel  310  to the second storage compartment  131 . 
     Particularly, as described above, in the state in which the damper  520  closes the passing flow path  501 , the passing flow path  501  may be affected by the temperature of the second storage compartment  131 , but the supply flow path  401  inside the supply duct  400  may be affected by the temperature of the first storage compartment  121 . 
     Here, when it is considered that the second storage compartment  131  is maintained at temperature lower than the temperature of the first storage compartment  121 , due to temperature difference therebetween, dew (condensate water) may be generated on the surface of the damper  520 , on the damper cover  510 , or on the inside of the supply duct  400 . In this case, dew generated inside the passing flow path of the damper cover  510  may be naturally removed by dry cold air. However, in the supply duct  400 , dew may be continuously generated due to humid air in the second storage compartment  131 , and in this process, the dew may be frozen by cold heat conducted from the damper assembly  500 . 
     In consideration of this, as described above, when the damper  520  closes the passing flow path  501 , at least one heater of the first heater  600  and the second heater  700  may be controlled to periodically generate heat. 
     The first heater  600  and the second heater  700  may be controlled to generate heat at the same time, and only one heater thereof may be controlled to generate heat. However, it is preferable that the two heaters  600  and  700  are controlled to simultaneously generate heat so as to sufficiently defrost an entire portion inside the supply duct  400 . 
     Accordingly, due to the heating of the first heater  600  and the second heater  700  described above, the damper assembly  500 , the supply duct  400 , and the connection portion of the damper assembly  500  with the supply duct  400  may be prevented from freezing. 
     Particularly, the first heater  600  and the second heater  700  may stop heating for a longer period of time when room temperature RT is within the second preset temperature range rather than the first preset temperature range so as to minimize power consumption. 
     Of course, under at least one condition of special conditions below, at least one heater of the first heater  600  and the second heater  700  may be controlled to continuously generate heat regardless of the opening/closing of the passing flow path by the damper  520 . 
     For example, when the refrigerator is initially powered on, at least one heater  600  or  700  may generate heat for a predetermined period of time regardless of the opening/closing of the passing flow path by the damper  520 . 
     In addition, when the internal temperature of at least one storage compartment of the first storage compartment  121  and the second storage compartment  131  is lower than the lower limit reference temperature NT−Diff of the satisfactory temperature NT±Diff designated relative to the preset reference temperature NT, at least one heater  600  or  700  may generate heat such that the internal temperature reaches the satisfactory temperature. 
     Additionally, during the occurrence of the error of one sensor related to the defrosting operation provided in the refrigerator, at least one heater  600  or  700  may generate heat to prevent the freezing of the evaporator  810  or each portion. 
     In addition, when the indoor humidity is higher than humidity preset at high humidity, any one heater  600  or  700  may generate heat. In this case, the indoor humidity may be humidity of the surrounding area of the refrigerator, and the preset humidity may be relative humidity of at least 80%. That is, in a very humid summer (for example, a rainy season), when the surrounding area of the refrigerator is maintained in a high humidity state, there is a high risk of freezing in the surrounding area, and thus at least one heater  600  or  700  may be controlled to generate heat. 
     Furthermore, when a defrost operation condition for the evaporator  810  of the associated refrigerator is satisfied (for example, when a compressor&#39;s operating integration time exceeds a preset time), at least one heater  600  or  700  may generate heat. 
     Additionally, in the case of a refrigerator in which an ice making compartment is provided in one refrigerator door  122  or  132 , during the ice making or ice separation of at least one of the ice maker (not shown) of the associated ice making compartment and an ice maker (not shown) in the second storage compartment  131 , at least one heater  600  or  700  may generate heat. 
     After all, in the refrigerator of the present disclosure, the first heater  600  may be provided in the damper assembly  500 , so the freezing of the damper assembly  500  or the freezing of the connection portion of the damper assembly  500  with the supply duct  400  may be prevented. 
     In addition, in the refrigerator of the present disclosure, the first heater  600  as a surface heating body may be installed along the surface of the damper  520 , sufficient heat for defrosting may be supplied not only to the inside of the damper assembly  500  but also to the inside of the supply duct  400 . 
     Additionally, in the refrigerator of the present disclosure, the second heater  700  may be provided in the supply duct  400 , thereby preventing the freezing of the supply duct  400  or the connection portion of the supply duct  400  with the damper assembly  500 . 
     Furthermore, in the refrigerator of the present disclosure, the second heater  700  may be configured as a coil heater and may be installed along the outer surface of the supply duct  400 , thereby supplying sufficient heat for defrosting to the connection portion of the damper assembly  500  with the supply duct  400  and to the inside of the supply duct  400 . 
     In addition, in the refrigerator of the present disclosure, the reverse step  402  which some of flowing cold air hits may be formed in the communication portion of the supply flow path  401  with the passing flow path  501 , thereby preventing freezing which may occur in the associated communication portion. 
     Additionally, in the refrigerator of the present disclosure, the guide rib  430  may be formed on the inner surface of the supply duct  400  by protruding therefrom, thereby allowing condensate water or defrost water generated in the supply duct  400  to flow down to the refrigerating compartment maintained at temperature higher than a dew point temperature. 
     Furthermore, in the refrigerator of the present disclosure, the first heater  600  and the second heater  700  may be controlled to generate heat only when the damper  520  is opened except under a special condition, thereby preventing impact on the internal temperature of each of the storage compartments  121  and  131  due to excessive heating operation of each of the heaters  600  and  700  and minimizing power consumption. 
     Meanwhile, the refrigerator of the present disclosure may be embodied in different forms. 
     For example, in the refrigerator of the present disclosure, the first heater  600  may not be provided, but only the second heater  700  may be provided. 
     Of course, when only the second heater  700  is provided, it is difficult to effectively prevent the freezing of the damper  520  as mentioned in the description of each of the heaters  600  and  700  according to the above-described embodiment, and due to heat generated by the high output of the second heater, power consumption is inevitably increased. 
     However, when the second heater  700  includes a plurality of second heaters, the above-mentioned disadvantages may be solved. That is, one coil heater  701  having a relatively high output may be disposed on the connection portion of the supply duct  400  with the damper assembly which has high risk of freezing (or the connection portion of the supply duct  400  with the second grille assembly) in the outer surface of the supply duct  400 , and another coil heater  702  having a relatively low output may be disposed on the center portion of the supply duct  400 . This is illustrated in  FIG. 20 . 
     It is also possible to dispose a larger number of coil heaters  701  intensively on a part of the outer surface of the supply duct  400  on which there is the high risk of freezing. 
     Accordingly, the refrigerator of the present disclosure may be embodied in various forms. 
     Accordingly, the present disclosure has been made keeping in mind the above problems occurring in the related art, and the present disclosure is intended to propose a refrigerator in which a supply duct configured to guide the flow of cold air from one storage compartment to another storage compartment, and a damper configured to open/close the supply duct may be prevented from freezing. 
     In addition, the present disclosure is intended to propose a refrigerator in which defrost water generated in the supply duct may flow to the refrigerating compartment such that the defrost water may be prevented from being supplied to the freezer compartment to be frozen. 
     Furthermore, the present disclosure is intended to propose a refrigerator in which the surface temperature of the supply duct may be raised to prevent the freezing of the inside of the supply duct. 
     Additionally, the present disclosure is intended to propose a refrigerator in which a heater may be provided to prevent the freezing of the damper, and impact which the operation of the heater affects the internal temperature of the refrigerating compartment may be minimized such that power consumption is minimized. 
     In order to achieve the above objectives, according to one aspect of the present disclosure, there is provided a refrigerator in which at least one of a damper assembly, a supply duct, and the connection portion of the damper assembly with the supply duct may be heated. Accordingly, the malfunction of the damper may be prevented. 
     According to the refrigerator of the present disclosure, a first heater which prevents the freezing of the damper assembly or the connection portion of the damper assembly with the supply duct may be prevented. 
     According to the refrigerator of the present disclosure, the first heater may be provided in the damper assembly or the connection portion of the damper assembly with the supply duct. 
     In addition, according to the refrigerator of the present disclosure, the supply duct may include a second heater which prevents the freezing of the connection portion of the supply duct with the damper assembly or the inside of the supply duct. 
     In addition, according to the refrigerator of the present disclosure, the cold air introduction portion of a supply flow path may be configured to be smaller than the cold air discharge portion of a passing flow path. 
     In addition, according to the refrigerator of the present disclosure, a step may be formed at the connection portion of the cold air introduction portion of the supply flow path with the cold air discharge portion of the passing flow path. 
     In addition, according to the refrigerator of the present disclosure, the upper portion of the cold air introduction portion of the supply flow path may be located at a position lower than the upper portion of the cold air discharge portion of the passing flow path. 
     In addition, according to the refrigerator of the present disclosure, the step may be formed to be larger than an assembly tolerance. 
     In addition, according to the refrigerator of the present disclosure, the step may be formed to be within 5 mm. 
     In addition, according to the refrigerator of the present disclosure, a guide rib which guides the flow of defrost water may be formed on the inner surface of the supply duct such that the guide rib is inclined or rounded. 
     In addition, according to the refrigerator of the present disclosure, the guide rib may be configured to have the protrusion height of 1.5 mm to 2 mm. Accordingly, resistance against the flow of cold passing through the supply flow path may be minimized and defrost water may be accurately guided. 
     In addition, according to the refrigerator of the present disclosure, the first heater may be provided on the outer surface of the damper. 
     In addition, according to the refrigerator of the present disclosure, the first heater may be configured as a surface heating body. 
     In addition, according to the refrigerator of the present disclosure, the first heater may be located on a surface of the outer surfaces of the damper directed to the supply duct. 
     In addition, according to the refrigerator of the present disclosure, the second heater may be provided on the outer surface of the supply duct. 
     In addition, according to the refrigerator of the present disclosure, the second heater may be configured as a coil heater. 
     In addition, according to the refrigerator of the present disclosure, the second heater may be installed on an edge formed on the connection portion of the supply duct with the damper assembly in the outer surface of the supply duct. 
     In addition, according to the refrigerator of the present disclosure, at least a portion of the second heater may be installed to be located at the center portion of the outer surface of the supply duct. 
     In addition, according to the refrigerator of the present disclosure, the second heater may be located to be adjacent to the connection portion of the supply duct with the damper assembly. 
     In addition, according to the refrigerator of the present disclosure, the second heater may be installed to be in more contact with the upper portion of the supply duct. 
     In addition, according to the refrigerator of the present disclosure, the first heater may be configured to have a higher output value than the second heater. 
     In addition, according to the refrigerator of the present disclosure, a controller which controls the heat generation of the first heater and the second heater may be included. 
     In addition, according to the refrigerator of the present disclosure, the controller may control at least one heater of the first heater and the second heater such that the at least one heater of the first heater and the second heater stops heating when the damper opens the passing flow path. 
     In addition, according to the refrigerator of the present disclosure, when the damper closes the passing flow path, the controller may control at least one heater of the first heater and the second heater such that the at least one heater of the first heater and the second heater continues heating, or repeatedly performs and stops heating according to room temperature outside the refrigerator. 
     In addition, according to the refrigerator of the present disclosure, when the room temperature is within a first preset temperature range, the controller may control at least one heater of the first heater and the second heater such that the at least one heater of the first heater and the second heater repeatedly performs and stops heating for a preset period of time. 
     In addition, according to the refrigerator of the present disclosure, when the room temperature is within a second preset temperature range lower than the first preset temperature range, the controller may control at least one heater of the first heater and the second heater such that the at least one heater of the first heater and the second heater is maintained to continue heating. 
     In addition, according to the refrigerator of the present disclosure, when the room temperature is within a third preset temperature range higher than the first preset temperature range, the controller may control at least one heater of the first heater and the second heater such that the at least one heater of the first heater and the second heater repeatedly performs and stops heating for a preset period of time. 
     In addition, according to the refrigerator of the present disclosure, heating interruption time when the room temperature is within the first preset temperature range may be preset to be shorter than heating interruption time when the room temperature is within the third preset temperature range. 
     In addition, according to the refrigerator of the present disclosure, when indoor humidity is higher than preset humidity, the controller may control at least one heater of the first heater and the second heater such that the at least one heater of the first heater and the second heater is maintained to continue heating. 
     In addition, according to the refrigerator of the present disclosure, when the refrigerator is under a special condition, the controller may control at least one heater of the first heater and the second heater such that the at least one heater of the first heater and the second heater generates heat regardless of whether the passing flow path is opened or closed by the damper. 
     As described above, the refrigerator of the present disclosure may have the following effects. 
     First, in the refrigerator of the present disclosure, the first heater may be provided in the damper assembly, thereby preventing the freezing of the damper assembly or the connection portion of the damper assembly with the supply duct. 
     In addition, in the refrigerator of the present disclosure, the first heater may be configured as a surface heating body and may be installed along the surface of the damper, thereby supplying sufficient heat for defrosting to the damper assembly and to the inside of the supply duct to prevent freezing thereof. 
     In addition, in the refrigerator of the present disclosure, the second heater may be provided in the supply duct, thereby preventing the freezing of the supply duct or the connection portion of the supply duct with the damper assembly. 
     In addition, in the refrigerator of the present disclosure, the second heater may be configured as a coil heater, and may be installed along the outer surface of the supply duct, thereby supplying sufficient heat to the connection portion of the damper assembly with the supply duct and to the inside of the supply duct to prevent freezing thereof. 
     In addition, in the refrigerator of the present disclosure, a reverse step with which some of flowing cold air hits may be formed in the communication portion of the supply flow path with the passing flow path, thereby preventing freezing which may occur in the associated communication portion. 
     In addition, in the refrigerator of the present disclosure, the guide rib may be formed on the inner surface of the supply duct by protruding therefrom, thereby allowing condensate water or defrost water generated in the supply duct to flow down to the refrigerating compartment maintained at temperature higher than a dew point temperature to prevent freezing. 
     In addition, in the refrigerator of the present disclosure, the first heater and the second heater may be controlled to generate heat only when the damper is opened except under a special condition, thereby preventing impact on the internal temperature of each of storage compartments due to the excessive heating operation of each of the heaters and minimizing power consumption. 
     It will be understood that when an element or layer is referred to as being “on” another element or layer, the element or layer can be directly on another element or layer or intervening elements or layers. In contrast, when an element is referred to as being “directly on” another element or layer, there are no intervening elements or layers present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that, although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section could be termed a second element, component, region, layer or section without departing from the teachings of the present invention. 
     Spatially relative terms, such as “lower”, “upper” and the like, may be used herein for ease of description to describe the relationship of one element or feature to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “lower” relative to other elements or features would then be oriented “upper” relative to the other elements or features. Thus, the exemplary term “lower” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Embodiments of the disclosure are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the disclosure. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the disclosure should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.