Patent Publication Number: US-11644230-B2

Title: Refrigerator

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a 371 National Stage of International Application No. PCT/KR2019/001970, filed Feb. 19, 2019, which claims priority to Korean Patent Application No. 10-2018-0036769, filed Mar. 29, 2018, the disclosures of which are herein incorporated by reference in their entirety. 
     BACKGROUND 
     1. Field 
     The disclosure relates to a refrigerator, and more specifically, to a refrigerator having a defrosting device capable of improving the defrosting efficiency. 
     2. Description of Related Art 
     In general, a refrigerator stores various types of food to be kept fresh for a long period of time by supplying a storage compartment with cold air that is generated by an evaporator. The storage compartment of the refrigerator is divided into a refrigerating compartment to keep food at about 3° C. above zero and a freezing compartment for keeping food frozen at about 20° C. below zero. 
     Specifically, the refrigerator includes an evaporator in which a low-pressure and low-temperature refrigerant evaporates while absorbing surrounding heat to exchange heat with indoor air in the storage compartment. In this case, water vapor introduced into the compartment from the outside at the room temperature or water vapor resulting from moisture contained in food stored in the compartment is frosted on the outer surface of the evaporator at a low temperature due to a temperature difference. 
     Since the frost formed on the surface of the evaporator lowers the heat exchange efficiency, lowers the cooling efficiency of the refrigerator, and increases the power consumption, a defrosting device for removing the frost is provided in the refrigerator. 
     The defrosting device may remove frost on the evaporator using a heater. In this case, the heater is located below the evaporator, causing a temperature difference between the upper end and the lower end of the evaporator, and thus a great amount of energy is inputted, thereby increasing the defrost energy and the power consumption of the refrigerator. 
     In addition, such a configuration increases the temperature in the storage compartment, and deteriorates food storage performance. 
     SUMMARY 
     Therefore, it is an object of the disclosure to provide a refrigerator including a defrosting device capable of improving defrosting efficiency. 
     It is another object of the disclosure to provide a refrigerator capable of improving power consumption by minimizing defrost energy by shortening a defrost time. 
     It is another object of the disclosure to provide a refrigerator capable of improving food storage performance by preventing the temperature of a storage compartment from increasing due to defrosting heat. 
     According to an aspect of the disclosure, there is provided a refrigerator including: a main body; a storage compartment provided inside the main body; an evaporator provided in the storage compartment and configured to generate cold air; a first flow path allowing air to be guided in a first direction for the air to be supplied to the storage compartment during a cooling operation; a defrosting heater configured to generate heat for defrost; a second flow path allowing air to be guided in a second direction opposite to the first direction for the air to be circulated around the evaporator during a defrosting operation; a fan allowing air having received heat from the defrosting heater to be circuited around the evaporator through the second flow path; and a flow path resistance portion provided on the second flow path to increase a flow path resistance in the first direction. 
     The first flow path may be configured to: allow air having transferred heat to the evaporator to be guided to the storage compartment during the cooling operation; and allow air having received heat from the defrosting heater to be guided to the second flow path. 
     The flow path resistance portion may be disposed at a lower portion of the second flow path. 
     The second flow path may allow air having passed through the first flow path to be guided in the second direction during the defrosting operation. 
     The flow path resistance portion may include a plurality of flow path resistance members that are asymmetrically arranged. 
     The plurality of flow path resistance members may be obliquely formed to reduce a flow resistance in a direction from an upper side to a lower side of the second flow path. 
     The plurality of flow path resistance members may be provided in different sizes. 
     The plurality of flow path resistance members may include at least one of a triangular shape, a streamlined shape, a wave shape, a polygonal shape, or a hemispherical shape. 
     The plurality of flow path resistance members may be formed in different sizes and shapes, and may be alternately arranged in a zigzag manner. 
     The refrigerator may further include a defrosting case that forms the second flow path, wherein the defrosting case may include: a first case; and a second case coupled to the first case to form the second flow path therein. 
     The plurality of flow path resistance members may be arranged on at least one of the first case or the second case. 
     The defrosting case may include a fan installation portion on which the fan is installed. 
     The defrosting case may include: an inlet allowing heat of the defrosting heater to be introduced into the second flow path after passing through the evaporator; and an outlet allowing air having passed through the second flow path to be discharged toward the evaporator. 
     The plurality of flow path resistance member may be integrally injection molded with the defrosting case. 
     According to another aspect of the disclosure, there is provided a refrigerator including: a main body; a storage compartment provided inside the main body; an evaporator provided in the storage compartment and configured to generate cold air; a first flow path allowing cold air to be guided to the storage compartment during a cooling operation; a first fan configured to move air in the first flow path to the storage compartment; and a defrosting device configured to remove frost, wherein the defrosting device may include: a defrosting heater configured to generate heat for defrost; a defrosting case forming a second flow path that allows air having received heat from the defrosting heater to be circulated around the evaporator; a second fan installed on the defrosting case and allowing air having passed through the first flow path to be guided to the second flow path during a defrosting operation; and a plurality of flow path resistance members provided in the second flow path. 
     The first fan and the second fan may rotate in opposite directions. 
     The flow path resistance member may be integrally injection molded with the defrosting case. 
     The first flow path may allow air having transferred heat to the evaporator to move from an upper side to a lower side during the cooling operation. 
     The flow path resistance member may be disposed at a lower portion of the second flow path to prevent air from moving to the second flow path during the cooling operation. 
     The plurality of flow path resistance members may be formed in different sizes and shapes, and may be alternately arranged in a zigzag manner. 
     Advantageous Effects 
     As is apparent from the above, the defrosting time is shortened so that defrost energy is minimized, thereby enhancing defrost efficiency and improving power consumption. 
     In addition, the temperature of a storage compartment is prevented from increasing due to defrosting heat, thereby improving food storage performance. 
     In addition, a damper is omitted unlike the existing technology, thereby improving the internal capacity of the storage compartment, reducing material cost, and improving the installation space and structural efficiency. 
     In addition, an asymmetric flow path shape with large flow resistance during general cooling operation and small flow resistance during defrosting operation is used, so that damage caused by a portion of air passing through an evaporator and then moving through a defrosting flow path can be minimized and the defrost time can be shortened. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a view illustrating a refrigerator according to an embodiment of the disclosure. 
         FIG.  2    is a cross-sectional view illustrating a refrigerator provided with a defrosting device according to an embodiment of the disclosure. 
         FIG.  3    is a perspective view illustrating a defrosting device according to an embodiment of the disclosure. 
         FIG.  4    is an exploded perspective view illustrating a defrosting device according to an embodiment of the disclosure. 
         FIG.  5    is a front view illustrating a flow path resistance portion of a defrosting device according to an embodiment of the disclosure. 
         FIG.  6    is a view illustrating an operation of a flow path resistance portion according to an embodiment of the disclosure. 
         FIG.  7    is a schematic diagram illustrating a flow of air by a defrosting device according to an embodiment of the disclosure. 
         FIG.  8    is a view illustrating a defrosting device provided with a flow path resistance portion according to a second embodiment of the disclosure. 
         FIG.  9    is a view illustrating a defrosting device provided with a flow path resistance portion according to a third embodiment of the disclosure. 
         FIG.  10    is a view illustrating a defrosting device provided with a flow path resistance portion according to a fourth embodiment of the disclosure. 
         FIG.  11    is a view illustrating a defrosting device provided with a flow path resistance portion according to a fifth embodiment of the disclosure; 
         FIG.  12    is a partially exploded perspective view illustrating a defrosting device provided with a flow path resistance portion according to a sixth embodiment of the disclosure. 
         FIG.  13    is a view illustrating a cross-section of a defrosting device provided with a flow path resistance portion according to a sixth embodiment of the disclosure. 
         FIG.  14    is a partially exploded perspective view illustrating a defrosting device according to a seventh embodiment of the disclosure. 
         FIG.  15    is a schematic diagram illustrating a flow of air by a defrosting device according to a seventh embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments set forth herein and illustrated in the configuration of the present disclosure are only the most preferred embodiments and are not representative of the full the technical spirit of the present disclosure, so it should be understood that they may be replaced with various equivalents and modifications at the time of the disclosure. 
     Throughout the drawings, like reference numerals refer to like parts or components. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. It is to be understood that the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. It will be further understood that the terms “include”, “comprise” and/or “have” 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. 
     The terms including ordinal numbers like “first” and “second” may be used to explain various components, but the components are not limited by the terms. The terms are only for the purpose of distinguishing a component from another. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the disclosure. Descriptions shall be understood as to include any and all combinations of one or more of the associated listed items when the items are described by using the conjunctive term “˜ and/or ˜,” or the like. 
     Hereinafter, embodiments according to the disclosure will be described in detail with reference to the accompanying drawings. 
       FIG.  1    is a view illustrating a refrigerator according to an embodiment of the disclosure,  FIG.  2    is a cross-sectional view illustrating a refrigerator provided with a defrosting device according to an embodiment of the disclosure,  FIG.  3    is a perspective view illustrating a defrosting device according to an embodiment of the disclosure,  FIG.  4    is an exploded perspective view illustrating a defrosting device according to an embodiment of the disclosure,  FIG.  5    is a front view illustrating a flow path resistance portion of a defrosting device according to an embodiment of the disclosure,  FIG.  6    is a view illustrating an operation of a flow path resistance portion according to an embodiment of the disclosure, and  FIG.  7    is a schematic diagram illustrating a flow of air by a defrosting device according to an embodiment of the disclosure. 
     Referring to  FIGS.  1  to  7   , a refrigerator  1  may include a main body  10 , a storage compartment (a freezing compartment  20  and a refrigerating compartment  30 ) formed inside the main body  10 , and an evaporator  40  supplying the storage compartments  20  and  30  with cold air. 
     The main body  10  includes an inner case  10   b  forming the storage compartments  20  and  30 , an outer case  10   a  coupled to an outer side of the inner case  10   b  to form the external appearance of the refrigerator  1 , and an insulating material  10   c  arranged between the inner case  10   b  and the outer case  10   a  to insulate the storage compartments  20  and  30 . 
     The storage compartments  20  and  30  may be divided into the refrigerating compartment  20  at an upper side and the freezing compartment  30  at a lower side by an intermediate partition  11 . The refrigerating compartment  20  is kept at a temperature of about 3° C. above zero to store food refrigerated, and the freezing compartment  30  is kept at a temperature of about 18.5° C. below zero to store food frozen. A shelf for placing food thereon and at least one storage box  24  for storing food may be provided in the refrigerator compartment  20 . 
     The refrigerating compartment  20  and the freezing compartment  30  each have an open front to allow food to be put in and out, and the open front of the refrigerating compartment  20  is opened and closed by a pair of doors  21  ( 21   a  and  21   b ) hinged to the main body  10 . The open front of the freezing compartment  30  may be opened and closed by a sliding door  31  that is slidable in a forward and backward direction with respect to the main body  10 . 
     A machine room (not shown) accommodating a compressor (not shown) for compressing a refrigerant and a condenser (not shown) for condensing the compressed refrigerant is provided at a lower rear side of the main body  10 . 
     An evaporator  40  for cooling the storage compartments  20  and  30  is installed at an inner rear side of the storage compartments  20  and  30 , and a blower fan (hereinafter, referred to as a first fan  51 ) that circulates cold air into the storage compartments  20  and  30  is installed above the evaporator  40 , and a cold air duct  50  is provided to guide the cold air induced by the first fan  51  to the storage compartments  20  and  30  to be discharged to the storage compartments  20  and  30 . 
     A defrosting heater  70  for removing frost on the evaporator  40  is provided below the evaporator  40 . The defrosting heater  70  removes ice or frost generated on the evaporator  40  and an outlet (not shown) provided in the cold air duct  50  so that cold air is smoothly discharged to the storage compartments  20  and  30 . 
     The defrosting heater  70  may include at least one of a sheath heater, a cord heater, a high-temperature gas of a cycle itself, or a heat pump cycle. 
     The cold air duct  50  is provided behind the storage compartments  20  and  30  such that cold air generated by the evaporator  40 , that is, air having transferred heat to the evaporator  40 , is induced to be supplied to the storage compartments  20  and  30 . 
     The evaporator  40  and the first fan  51  are mounted on the cold air duct  50 . The cold air duct  50  may be formed with a cold air outlet  52  so that the cold air generated by the evaporator  40  is supplied to the storage compartments  20  and  30 . The cold air outlet  52  may be formed in plural. 
     The cold air duct  50  includes a first flow path  210  such that the cold air generated by the evaporator  40  is supplied to the storage compartments  20  and  30  by the first fan  51  during a cooling operation. 
     The first flow path  210  is provided to allow air having transferred heat to the evaporator  40  to be guided to the storage compartments  20  and  30  during a cooling operation. The air having transferred heat to the evaporator  40  moves from a lower side of the first flow path  210  to an upper side of the first flow path  210  (hereinafter, referred to as a first direction A) by the first fan  51 . The cold air having transferred heat to the evaporator  40  moves in the first direction A of the first flow path  210 . In the embodiment of the disclosure, the evaporator  40  is illustrated as being provided behind the storage compartments  20  and  30  so that cold air is moved from the lower side to the upper side, but the concept of the disclosure is not limited thereto. For example, the evaporator may be disposed on a lower surface or an upper surface of the storage compartment to form a flow path in a direction corresponding to each of the lower surface and the upper surface. 
     The refrigerator  1  may include a defrosting device  100  provided to perform defrost. The defrosting device  100  includes a defrosting heater  70  generating heat for defrosting. The defrosting heater  70  may be provided below the evaporator  40 . Air heated by the defrosting heater  70  is caused to rise and move by convection. In the embodiment of the disclosure, the cold air duct  50  and the first flow path  210  are illustrated as being provided in an upper and lower side direction so that air heated by the defrosting heater  70  moves from the lower side to the upper side (the first direction A), but the concept of the disclosure is not limited thereto. For example, the cold air duct and the evaporator may be arranged on the lower surface or the upper surface of the storage compartment. In addition, the defrosting heater is illustrated as being disposed below the ice maker, the concept of the disclosure is not limited thereto. For example, the ice making heater may be located on the top or side of the evaporator. 
     The defrosting device  100  may be disposed around the evaporator  40 . The defrosting device  100  may be disposed behind the evaporator  40 . The defrosting device  100  may be installed on the inner case  10   b  of the main body  10 . The defrosting device  100  may be disposed between the inner case  10   b  and the outer case  10   a  of the main body  10 . The defrosting device  100  may be fixed to the inner case  10   b  of the main body  10  by a fixing member, such as a bolt. The defrosting device  100  may be fixed by being pressed into the inner case  10   b.    
     The defrosting device  100  may include a defrosting case  110  and a defrosting fan (hereinafter, referred to as a second fan  120 ) installed in the defrosting case  110 . 
     The defrosting device  100  is provided such that, when air having received heat from the defrosting heater  70  is moved in the first direction A of the first flow path  210  by convection, the air having received heat from the defrosting heater moves to the second flow path  220  after passing through the first flow path  210 . 
     The second flow path  220  is provided such that air having received heat from the defrosting heater  70  circulates around the evaporator  40  during the defrost operation. The second fan  120  may be installed so that air having received heat from the defrosting heater  70  is circulated to the second flow path  220 . The second fan  120  is provided to allow air that has passed through the first flow path  210  to flow into the second flow path  220 . In this case, the first fan  51  and the second fan  120  are driven to rotate in opposite directions. The defrosting case  110  includes a first case  110   a  and a second case  110   b . The first case  110   a  and the second case  110   b  may be coupled through a case coupling portion  130 . A first case coupling portion  131  is provided on the first case  110   a , and a second case coupling portion  132  is provided on the second case  110   b . The second case coupling portion  132  may be provided at a position corresponding to the first case coupling portion  131 . The first case coupling portion  131  and the second case coupling portion  132  may be assembled to each other through a member, such as a bolt or a hook. 
     The second flow path  220  may be formed between the first case  110   a  and the second case  110   b . The first case  110   a  may be coupled to the inner case  10   b  of the main body  10 . In the embodiment of the disclosure, the defrosting case  110  is illustrated as being press-fitted and fixed to a defrosting device installation portion  12  formed on at least a part of the inner case  10   b  of the main body  10 , but the concept of the disclosure is not limited thereto. For example, the defrosting case may be fixed to the inner case having at least a part thereof open through a fixing member, such as a bolt. In this case, at least one side of the defrosting case may be fixed by the insulating material  10   c.    
     The defrosting case  110  includes an inlet  111  through which heat of the defrosting heater  70  passing through the evaporator  40  flows into the second flow path  220 , and an outlet  112  through which air passing through the second flow path  220  is discharged toward the evaporator  40 . 
     The inlet  111  and the outlet  112  may be each provided in the second case  110   b . The inlet  111  may be disposed on an upper portion of the second case  110   b , and the outlet  112  may be disposed at a lower portion of the second case  110   b . In the embodiment of the disclosure, the inlet and the outlet are illustrated as being provided in the second case  110   b , but the concept of the disclosure is not limited thereto. 
     The second fan  120  may be installed in at least one of the first case  110   a  or the second case  110   b . The defrosting case  110  includes a fan installation portion  114  on which the second fan  120  is installed. The fan installation portion  114  may be formed around the inlet  111  of the defrosting case  110  to guide air introduced through the inlet  111  of the defrosting case  110  to the second flow path  220 . The fan installation portion  114  may be disposed on an upper portion of the defrosting case  110 . The fan installation portion  114  may be disposed at the center of the upper portion of the second case  110   b . The fan installation portion  114  may be formed at a position corresponding to the inlet  111 . The fan installation portion  114  may include the inlet  111 . 
     Air having received heat from the defrosting heater  70  and passing through the first flow path  210  is introduced into the inlet  111  of the defrosting case  110  by the second fan  120  and guided to the second flow path  220 , and the air introduced into the inlet  111  is guided in the second direction B of the second flow path  220  and discharged through the outlet  112 . 
     The air discharged through the outlet  112  of the second flow path  220  moves toward the defrosting heater  70  again and receives heat from the defrosting heater  70 , in which the air is heated and the heated air moves back to the evaporator  40  so that the defrosting heat is circulated without leakage. 
     On the other hand, the second flow path  220  includes a flow path resistance portion  140  provided to prevent air having received heat from the defrosting heater  70  from bypassing during a cooling operation. 
     The flow path resistance portion  140  may be formed on an inner lower side of the second flow path  220 . The flow path resistance portion  140  is provided to form an asymmetric flow resistance inside the second flow path  220 . The flow path resistance portion  140  may be provided so that a resistance in an upward direction is large and a resistance in a downward direction is small because the flow of air during the cooling operation is directed upward. 
     The flow path resistance portion  140  includes a plurality of flow path resistance members  141 . The plurality of flow path resistance members  141  may be implemented in an asymmetric form on the surface of the second flow path  220 . The flow path resistance member  141  may have a triangular shape and may be disposed in the second flow path  220 . The flow path resistance member  141  may be formed to have a first thickness t 1 . The flow path resistance member  141  includes a first member  141   a  and a second member  141   b  connected to an upper end of the first member  141   a . The second member  141   b  is bent from the upper end of the first member  141   a  to extend perpendicular to the first member  141   a . The second member  141   b  and the first member  141   a  may be formed to have the same length. 
     The flow path resistance members  141  may be disposed in at least one line or more at the lower portion of the second flow path  220 . The flow path resistance members  141  may be disposed in a zigzag manner to implement asymmetry on the lower portion of the second flow path  220 . The flow path resistance member  141  is provided to reduce the downward flow resistance of the second flow path  220  and increase the upward flow resistance of the second flow path  220 . The flow path resistance member  141  may be disposed in at least one of the first case  110   a  or the second case  110   b . The flow path resistance member  141  may be injection-molded integrally with the defrosting case  110 . The flow path resistance member  141  may be injection-molded integrally with the first case  110   a . The flow path resistance member  141  may be injection-molded integrally with the second case. 
       FIG.  7    is a schematic diagram illustrating a flow of air by the defrosting device  100  of the refrigerator  1  during a cooling operation and a defrosting operation. 
     During the cooling operation of the refrigerator  1 , the evaporator  40  generates cold air through heat exchange of a refrigerant, and the cold air generated by the evaporator  40  is moved in the first direction A by the first fan  51  provided above the evaporator  40 , and supplied to each of the storage compartments  20  and  30  by being guided to the cold air duct  50 . 
     In this case, the flow path resistance portion  140  of the defrosting device  100  is provided to increase the flow resistance in the upward direction such that air having transferred heat to the evaporator  40  does not flow to the second flow channel  220 . 
     During the defrosting operation of the refrigerator  1 , the defrosting heater  70  of the defrosting device  100  is operated. The hot air heated by the defrosting heater  70  rises by convection. The air having received heat from the defrosting heater  70  removes frost on the evaporator  40 , passes through the first flow path  210 , and then enters the second flow path  220  by the second fan  120 . 
     In this case, the first fan  51  and the second fan  120  may be operated by rotating in opposite directions. 
     The air introduced into the second flow path  220  by the second fan  120 , which has received heat from the defrosting heater  70 , is moved in the second direction B and discharged through the outlet  112 , and the air discharged through the outlet  112  is heated again by the defrosting heater  70  and moved to the evaporator  40  and circulated. 
     In this case, the flow path resistance portion  140  provided in the second flow path  220  is provided to reduce the flow resistance in the downward direction, thereby promoting the flow of air heated by receiving heat from the defrosting heater  70 . 
     Conversely, the flow path resistance portion  140  provided in the second flow path  220  is provided to increase the flow resistance in the upper direction, thereby minimizing the loss of cold air bypassed by the second flow path  220  during a cooling operation. 
     Accordingly, the flow path resistance portion  140  of the defrosting device  100  increases the flow resistance of cold air toward the second flow path  220  during the cooling operation, and decreases the flow resistance of heated air toward the second flow path  220  during the defrosting operation, thereby minimizing a loss of cold air due to cold air flowing to the second flow path  220  during a cooling operation and shortening the defrost time through circulation of heated air so that the defrost energy may be improved. 
       FIG.  8    is a view illustrating a defrosting device provided with a flow path resistance portion according to a second embodiment of the disclosure. Reference numerals not shown are referenced to  FIGS.  1  to  7   . 
     Referring to  FIG.  8   , a flow path resistance portion  140 A of the defrosting device  100  includes a plurality of flow path resistance members  141 A. 
     The flow path resistance member  141 A may be implemented in an asymmetric form on the surface of the second flow path  220 . The flow path resistance member  141 A may be disposed on a lower portion of the defrosting case  110 . The flow path resistance member  141 A may be disposed in at least one of the first case  110   a  or the second case  110   b . The flow path resistance member  141 A may include a first resistance member  141 Aa formed on the first case  110   a  and a second resistance member  141 Ab formed on the second case  110   b.    
     The first resistance member  141 Aa and the second resistance member  141 Ab may be alternately disposed. The first resistance member  141 Aa and the second resistance member  141 Ab may be formed to have an inclination of a first angle θ 1  on the first case  110   a  and the second case  110   b , respectively. The first resistance member  141 Aa is formed to have an inclination of a first angle θ 1  with respect to the first case  110   a  at the upper portion thereof. The second resistance member  141 Ab is formed to have an inclination of a first angle θ 1  with respect to the second case  110   b  at the upper portion thereof. 
     The flow path resistance members  141 A may be disposed to implement asymmetry on the lower portion of the second flow path  220 . The flow path resistance member  141 A is provided to reduce the downward flow resistance of the second flow path  220  and increase the upward flow resistance of the second flow path  220 . The flow path resistance member  141 A may be injection-molded integrally with the defrosting case  110 A. The first resistance member  141 Aa of the flow path resistance member  141 A may be injection-molded integrally with the first case  110   a . The second resistance member  141 Ab of the flow path resistance member  141 A may be injection-molded integrally with the second case  110   b.    
     The flow path resistance portion  140 A provided on the second flow path  220  increases the flow resistance in the upper direction during a cooling operation, thereby minimizing a loss of cold air bypassed by the second flow path  220 . 
     In addition, during the defrosting operation, the flow path resistance portion  140 A is provided to reduce the flow resistance in the downward direction to guide the flow of air having received heat from the defrosting heater  70 . That is, the flow path resistance portion  140 A of the defrosting device  100  increases the flow resistance of the cold air during the cooling operation and decreases the flow resistance of the heated air during the defrosting operation, thereby minimizing the loss caused by cold air flowing to the second flow path  220  during a cooling operation while reducing the defrost time so that defrost energy is improved. 
     Meanwhile, since the flow of air by the flow path resistance portion  140 A of the second flow path  220  according to the embodiment of the disclosure may be identical to that according to the first embodiment of the disclosure, a detailed description thereof will be omitted. 
       FIG.  9    is a view illustrating a defrosting device provided with a flow path resistance portion according to a third embodiment of the disclosure. Reference numerals not shown are referenced to  FIGS.  1  to  7   . 
     Referring to  FIG.  9   , a flow path resistance portion  140 B of the defrosting device  100  includes a plurality of flow path resistance members  141 B. 
     The flow path resistance member  141 B may be implemented in an asymmetric form on the surface of the second flow path  220 . The flow path resistance member  141 B may be disposed on a lower portion of the defrosting case  110 . The flow path resistance member  141 B may be disposed in at least one of the first case  110   a  or the second case  110   b . The flow path resistance member  141 B may include a first resistance member  141 Ba formed on the first case  110   a  and a second resistance member  141 Bb formed on the second case  110   b.    
     The first resistance member  141 Ba and the second resistance member  141 Bb may be disposed to be opposite to each other. The first resistance member  141 Ba and the second resistance member  141 Bb may be formed to have an inclination of a second angle θ 2  on the first case  110   a  and the second case  110   b , respectively. The first resistance member  141 Ba is formed to have an inclination of a second angle θ 2  with respect to the first case  110   a  at the upper portion thereof. The second resistance member  141 Bb is formed to have an inclination of a second angle θ 2  with respect to the second case  110   b  at the upper portion thereof. 
     The flow path resistance member  141 B may be disposed to implement asymmetry on the lower portion of the second flow path  220 . The flow path resistance member  141 B is provided to reduce the downward flow resistance of the second flow path  220  and increase the upward flow resistance of the second flow path  220 . The flow path resistance member  141 B may be injection-molded integrally with the defrosting case  110 B. 
     The flow path resistance portion  140 B of the defrosting device  100  increases the flow resistance of cold air toward the second flow path  220  during the cooling operation, and decreases the flow resistance of heated air during the defrosting operation, thereby minimizing a loss of cold air due to cold air flowing to the second flow path  220  and shortening the defrost time through circulation of heated air so that the defrost energy may be improved. 
     Meanwhile, since the flow of air by the flow path resistance portion  140 B of the second flow path  220  according to the embodiment of the disclosure may be identical to that according to the first embodiment of the disclosure, a detailed description thereof will be omitted. 
       FIG.  10    is a view illustrating a defrosting device provided with a flow path resistance portion according to a fourth embodiment of the disclosure. Reference numerals not shown are referenced to  FIGS.  1  to  7   . 
     A flow path resistance portion  140 C of the defrosting device  100  includes a plurality of flow path resistance members  141 C. 
     The flow path resistance member  141 C may be implemented in an asymmetric form on the surface of the second flow path  220 . The flow path resistance member  141 C may have a triangular shape and may be provided in the second flow path  220 . The flow path resistance members  141 C may be disposed in at least one line or more at the lower portion of the second flow path  220 . The flow path resistance member  141 C may be disposed in a zigzag manner to implement an asymmetry on the lower portion of the second flow path  220 . 
     The flow path resistance member  141  includes a first member  141 Ca disposed on the upper side, a second member  141 Cb disposed below the first member  141 Ca, and a third member  141 Cc disposed below the second member  141 Cb. 
     The first member  141 Ca, the second member  141 Cb, and the third member  141 Cc may have different sizes. The first member  141 Ca is formed larger than the second and third members  141 Cb and  141 Cc. The second member  141 Cb is formed larger than the third member  141 Cc. Asymmetric flow resistance may be implemented by variously changing the arrangement of the flow path resistance members  141 C provided in the same shape and different sizes. 
     The flow path resistance member  141 C is provided to reduce the downward flow resistance of the second flow path  220  and increase the upward flow resistance of the second flow path  220 . The flow path resistance member  141 C may be injection-molded integrally with the defrosting case  110 . 
     The flow path resistance portion  140 C increases the flow resistance of cold air toward the second flow path  220  during the cooling operation, and decreases the flow resistance of heated air during the defrosting operation, thereby minimizing a loss of cold air due to cold air flowing to the second flow path  220  and shortening the defrost time through circulation of heated air so that the defrost energy may be improved. 
     Meanwhile, since the flow of air by the flow path resistance portion  140 C of the second flow path  220  according to the embodiment of the disclosure may be identical to that according to the first embodiment of the disclosure, a detailed description thereof will be omitted. 
       FIG.  11    is a view illustrating a defrosting device provided with a flow path resistance portion according to a fifth embodiment of the disclosure. Reference numerals not shown are referenced to  FIGS.  1  to  7   . 
     A flow path resistance portion  140 D of the defrosting device  100  includes a plurality of flow path resistance members  141 D. 
     The flow path resistance member  141 D may be implemented in an asymmetric form on the surface of the second flow path  220 . The flow path resistance member  141 D may be provided in a streamlined shape in the second flow path  220 . The flow path resistance members  141 D may be disposed on the lower portion of the second flow path  220  in at least one line or more. The flow path resistance member  141 D may be disposed in a zigzag manner to implement an asymmetry on the lower portion of the second flow path  220 . The flow path resistance member  141 D may include a first resistance member  141 Da formed in a curved shape and a second resistance member  141 Db formed in a curved shape and connected to the first resistance member  141 Da. The first resistance member  141 Da and the second resistance member  141 Db may be formed to be symmetrical to each other. The flow path resistance member  141 D is provided to reduce the downward flow resistance of the second flow path  220  and increase the upward flow resistance of the second flow path  220 . The flow path resistance member  141 D may be injection-molded integrally with the defrosting case  110 . 
     The flow path resistance portion  140 D of the defrosting device  100  increases the flow resistance of cold air toward the second flow path  220  during the cooling operation, and decreases the flow resistance of heated air during the defrosting operation, thereby minimizing a loss of cold air due to cold air flowing to the second flow path  220  and shortening the defrost time through circulation of heated air so that the defrost energy may be improved. 
     Meanwhile, since the flow of air by the flow path resistance portion  140 D of the second flow path  220  according to the embodiment of the disclosure may be identical to that according to the first embodiment of the disclosure, a detailed description thereof will be omitted. 
       FIG.  12    is a partially exploded perspective view illustrating a defrosting device provided with a flow path resistance portion according to a sixth embodiment of the disclosure, and  FIG.  13    is a view illustrating a cross-section of a defrosting device provided with a flow path resistance portion according to a sixth embodiment of the disclosure. Reference numerals not shown are referenced to  FIGS.  1  to  7   . 
     Referring to  FIGS.  12  to  13   , a defrosting device  100 E includes a defrosting case  110 E. The defrosting case  110 E includes a first case  110 Ea and a second case  110 Eb. 
     The first case  110 Ea and the second case  110 Eb may be coupled to each other through a case coupling portion  130 E. The case coupling portion  131 E is provided on the first case  110 Ea. The second case  110 Eb is formed in a plate shape. The second case  110 Eb is coupled to the case coupling portion  131 E of the first case  110 Ea. 
     A second flow path  220 E is formed between the first case  110 Ea and the second case  110 Eb. The first case  110 Ea includes an inlet  111 E allowing heat of the defrosting heater  70  to flows into the second flow path  220 E after passing through the evaporator  40  and an outlet  112  allowing air passing through the second flow path  220 E to be discharged toward the evaporator  40 . 
     The inlet  111 E and the outlet  112 E may be each provided in the first case  110 Ea. The inlet  111 E may be disposed on an upper portion of the first case  110 Ea, and the outlet  112 E may be disposed on a lower portion of the first case  110 Ea. 
     The first case  110 Ea includes a fan installation portion  114 E on which a second fan  120 E is installed. The fan installation portion  114 E may be formed to guide air introduced through the inlet  111 E to the second flow path  220 E. 
     Air having received heat from the defrosting heater  70  and passing through the first flow path  210  is introduced into the inlet  111 E of the defrosting case  110 E by the second fan  120 E, and guided to the second flow path  220 E, and the air introduced into the inlet  111 E is guided in the second direction B of the second flow path  220 E and discharged through the outlet  112 E. 
     The air discharged through the outlet  112 E of the second flow path  220 E moves toward the defrosting heater  70  again and receives heat from the defrosting heater  70 , in which the air is heated, and the heated air moves back to the evaporator  40  so that the defrosting heat is circulated without leakage. 
     Meanwhile, the second flow path  220 E includes a flow path resistance portion  140 E that generates flow resistance to prevent air having received heat from the defrosting heater  70  from being bypassed and moved toward the storage compartments  20  and  30  during a cooling operation. 
     The flow path resistance portion  140 E may be formed in an asymmetric form. The flow path resistance portion  140 E is provided to form an asymmetric flow resistance. The flow path resistance portion  140 E may be provided so that a resistance in an upward direction is large and a resistance in a downward direction is small because the flow of air during the cooling operation is directed upward. 
     The flow path resistance portion  140 E includes a plurality of flow path resistance members  141 E. The flow path resistance member  141 E may be implemented in an asymmetric form on the surface of the second flow path  220 E. The flow path resistance member  141 E may be provided in a curved shape in the second flow path  220 E. The flow path resistance member  141 E may be arranged lengthwise along the traverse direction of the second flow path  220 E. The flow path resistance members  141 E have a streamline shape, and have a respective upper end fixed to a corresponding one of the first case  110 Ea and the second case  110 Eb. The lower end of the flow path resistance member  141 E is provided to be spaced apart from a corresponding one of the first case  110 Ea and the second case  110 Eb. 
     The flow path resistance members  141 E may be disposed in at least one line or more on the lower portion of the second flow path  220 E. The flow path resistance member  141 E is provided to reduce the downward flow resistance of the second flow path  220  and increase the upward flow resistance of the second flow path  220 . The flow path resistance member  141 E may be disposed in at least one of the first case  110 Ea and the second case  110 Eb. The flow path resistance member  141 E may include a first member  141 Ea provided on the first case  110 Ea and a second member  141 Eb provided on the second case  110 Eb. The first member  141 Ea and the second member  141 Eb may be spaced apart from each other and may be alternately disposed. The flow path resistance member  141 E may be injection-molded integrally with the defrosting case  110 E. 
     The flow path resistance portion  140 E of the defrosting device  100  increases the flow resistance of cold air toward the second flow path  220  during the cooling operation, and decreases the flow resistance of heated air during the defrosting operation, thereby minimizing a loss of cold air due to cold air flowing to the second flow path  220  and shortening the defrost time through circulation of heated air so that the defrost energy may be improved. 
     Meanwhile, since the flow of air by the flow path resistance portion  140 E of the second flow path  220 E according to the embodiment of the disclosure may be identical to that according to the first embodiment of the disclosure, a detailed description thereof will be omitted. 
       FIG.  14    is a partially exploded perspective view illustrating a defrosting device according to a seventh embodiment of the disclosure, and  FIG.  15    is a schematic diagram illustrating a flow of air by a defrosting device according to a seventh embodiment of the disclosure. Reference numerals not shown are referred to  FIGS.  1  to  7   . 
     Referring to  FIGS.  14  to  15   , a defrosting device  100 F includes a first case  110 Fa and a second case  110 Fb. 
     The first case  110 Fa and the second case  110 Fb may be coupled to each other through a case coupling portion  130 E. 
     A second flow path  220 F is formed between the first case  110 Fa and the second case  110 Fb. The second case  110 Fb includes an inlet  111 F allowing heat of the defrosting heater  70  to flows into the second flow path  220 F after passing through the evaporator  40 , and an outlet  112  allowing air passing through the second flow path  220 F to be discharged toward the evaporator  40 . 
     The second case  110 Fb includes a fan installation portion  114 F on which a second fan  120 F is installed. The fan installation portion  114 F may be formed to guide the air introduced through the inlet  111 F to the second flow path  220 F. 
     In this case, the fan installation portion  114 F may be provided so that the second fan  120 F is installed at a third angle θ 3 . The second fan  120 F may be installed at a third angle θ 3 . Through the second fan  120 F, air having received heat from the defrosting heater  70  passes through the first flow path  210  and enters the inlet  111 F of the defrosting case  110 F to be guided to the second flow path  220 F, and then guided in the second direction B of the second flow path  220 F and discharged through the outlet  112 F. 
     In addition, the air discharged through the outlet  112 F of the second flow path  220 F moves to the defrosting heater  70  again and receives heat from the defrosting heater  70 , in which the air is heated and the heated air moves back to the evaporator  40  so that defrosting heat is circulated without leakage. 
     The second fan  120 F is installed to have a predetermined angle in the second flow path  120 F, so that the defrosting flow of the second flow path  120 F is increased. 
     Meanwhile, the second flow path  220 F may further include an opening and closing member  160 F that is openable and closable so as to be closed by gravity and opened only in one direction by an operation of the second fan  120 F to prevent air having received heat from the defrosting heater  70  from moving toward the storage compartments  20  and  30  during a cooling operation. The opening and closing member  160 F may be installed at the outlet  112 F of the second flow path  220 F. The opening and closing member  160 F is provided to prevent air having transferred heat to the evaporator  40  from moving toward the second flow path  220 F during the cooling operation. The opening and closing member  160 F may include at least one of a damper or a valve. 
     The flow path resistance portion  140 F of the defrosting device  100  increases the flow resistance of cold air toward the second flow path  220  during the cooling operation, and decreases the flow resistance of heated air during the defrosting operation, thereby minimizing a loss of cold air due to cold air flowing to the second flow path  220  and shortening the defrost time through circulation of heated air so that the defrost energy may be improved. 
     Meanwhile, since the flow of air by the flow path resistance portion  140 F of the second flow path  220  according to the embodiment of the disclosure may be identical to that according to the first embodiment of the disclosure, a detailed description thereof will be omitted. 
     Although few embodiments of the disclosure have been shown and described, the above embodiment is illustrative purpose only, and it would be appreciated by those skilled in the art that changes and modifications may be made in these embodiments without departing from the principles and scope of the disclosure, the scope of which is defined in the claims and their equivalents.