Patent Publication Number: US-8966932-B2

Title: Refrigerator

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Korean Patent Application No. 2010-0087207, filed on Sep. 6, 2010 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     Embodiments relate to a refrigerator having an ice thermal storage device. 
     2. Description of the Related Art 
     Generally, a refrigerator is designed to keep stored items fresh for a long time using cold air supplied into a storage compartment thereof. The cold air supplied into the storage compartment is produced by heat-exchange of a refrigerant. The cold air is uniformly transferred throughout the storage compartment by convection, enabling storage of food at a desired temperature. 
     The storage compartment may be divided into a refrigerating compartment and a freezing compartment based on an interior temperature and a purpose thereof. The freezing compartment, which keeps food at a temperature below zero, may contain an ice thermal storage material, to enhance cooling efficiency of food. 
     The ice thermal storage material is sealed in a pack and is placed in the freezing compartment. In this case, if the pack enclosing the ice thermal storage material breaks, the ice thermal storage material is exposed to food, damaging the food. Moreover, if the ice thermal storage material varies in volume during phase change from liquid to solid, the ice thermal storage pack undergoes surface deformation, which may reduce a food contact area and cooling efficiency. 
     SUMMARY 
     It is an aspect to provide a refrigerator having an ice thermal storage device to enhance cooling efficiency. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention. 
     In accordance with one aspect, a refrigerator includes a cabinet, a storage compartment defined in the cabinet, and an ice thermal storage device placed in the storage compartment, wherein the ice thermal storage device includes a case including at least one heat transfer plate, and an ice thermal storage pack received in the case and arranged to come into contact with the at least one heat transfer plate. 
     The case may include an expansion induction region to provide an expansion space for the ice thermal storage pack, so as to maintain contact between the ice thermal storage pack and the heat transfer plate. 
     The case may include an upwardly protruding support bar spaced apart from an inner surface of the case by a predetermined distance and serving to support a lateral surface of the ice thermal storage pack. 
     The support bar may include a first support bar and a second support bar to support opposite lateral surfaces of the ice thermal storage pack respectively. 
     An upper end of the support bar may be located lower than an upper surface of the ice thermal storage pack. 
     The expansion induction region may be defined by a space between the upper end of the support bar and the inner surface of the case, and the ice thermal storage pack may be expandable into the expansion induction region. 
     The case may include an air-bubble guide region to guide interior air of the ice thermal storage pack during expansion of the ice thermal storage pack, so as to maintain contact between the ice thermal storage pack and the heat transfer plate. 
     The air-bubble guide region may be defined by a space above an upper edge of the ice thermal storage pack. 
     The heat transfer plate may be located above the air-bubble guide region. 
     The case may include a housing configured to receive the ice thermal storage pack therein and to support the heat transfer plate coupled thereto, and the housing may be located above the air-bubble guide region. 
     The case may include a first housing in which the ice thermal storage pack is received and a second housing to which the heat transfer plate is coupled, and the first housing and the second housing may be coupled to each other such that the heat transfer plate comes into close contact with the ice thermal storage pack. 
     The first housing may include an assembly groove for coupling of the second housing, and an end of the second housing, extending angularly from an upper surface of the second housing, may be fitted into the assembly groove. 
     The first housing may include an upwardly protruding fastening piece, the heat transfer plate may include a fastening hole provided at a position corresponding to the fastening piece, the second housing may include a downwardly open fastening recess provided at a position corresponding to the fastening piece, and the ice thermal storage device may be assembled as the fastening piece is successively fastened into the fastening hole and the fastening recess. 
     The ice thermal storage pack may include a fixing hole, the case may further include a fixing pin protruding toward the fixing hole so as to correspond to the fixing hole, and the ice thermal storage pack may be kept at a fixed position as the fixing pin is inserted into the fixing hole. 
     The case may further include a load carrying member to carry the heat transfer plate. 
     The load carrying member may divide the interior of the case into a plurality of spaces, and a plurality of ice thermal storage packs may be arranged respectively in the plurality of spaces. 
     The heat transfer plate may include a first heat transfer plate and a second heat transfer plate to come into contact with upper and lower surfaces of the ice thermal storage pack respectively. 
     The refrigerator may further include a shelf secured to an inner wall of the storage compartment, and the ice thermal storage device may be coupled to the shelf. 
     The shelf may include a support member fixed to the inner wall of the storage compartment and a shelf member slidably fitted into the support member, and the shelf member may include a seating recess indented to have a shape corresponding to that of the ice thermal storage device. 
     The refrigerator may further include a guide provided at the inner wall of the storage compartment, and the ice thermal storage device may further include a coupling portion coupled to the guide, the ice thermal storage device serving as a shelf. 
     The refrigerator may further include a storage container received in the storage compartment to provide a separate storage space, and the ice thermal storage device may be mounted to a lower surface of the storage container. 
     The heat transfer plate may be made of a metallic material. 
     The heat transfer plate may include a coating layer formed on at least one surface thereof. 
     In accordance with another aspect, an ice thermal storage device includes a case including at least one heat transfer plate, and an ice thermal storage pack received in the case and arranged to come into contact with the at least one heat transfer plate. 
     The case may include an expansion induction region to provide an expansion space for the ice thermal storage pack, so as to maintain contact between the ice thermal storage pack and the heat transfer plate. 
     The case may include an upwardly protruding support bar spaced apart from an inner surface of the case by a predetermined distance and serving to support a lateral surface of the ice thermal storage pack, and an upper end of the support bar may be located lower than an upper surface of the ice thermal storage pack. 
     The expansion induction region may be defined by a space between the upper end of the support bar and the inner surface of the case, and the ice thermal storage pack may be expandable into the expansion induction region. 
     The case may include an air-bubble guide region to guide interior air of the ice thermal storage pack during expansion of the ice thermal storage pack, so as to maintain contact between the ice thermal storage pack and the heat transfer plate. 
     The air-bubble guide region may be defined by a space above an upper edge of the ice thermal storage pack. 
     The case may further include a load carrying member to carry the heat transfer plate and divide the interior of the case into a plurality of spaces, and a plurality of ice thermal storage packs may be arranged respectively in the plurality of spaces. 
     The heat transfer plate may include a first heat transfer plate and a second heat transfer plate to come into contact with upper and lower surfaces of the ice thermal storage pack respectively. 
     The heat transfer plate may be made of a metallic material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  is a perspective view illustrating major components of a refrigerator in accordance with an embodiment; 
         FIG. 2  is a perspective view illustrating a shelf assembly provided in the refrigerator in accordance with the embodiment; 
         FIG. 3  is an exploded perspective view illustrating an ice thermal storage device in accordance with the embodiment; 
         FIG. 4A  is a sectional view of the ice thermal storage device in accordance with the embodiment; 
         FIG. 4B  is a sectional view of an ice thermal storage device in accordance with another embodiment; 
         FIG. 4C  is a sectional view of an ice thermal storage device in accordance with another embodiment; 
         FIG. 5  is a sectional view of an ice thermal storage device in accordance with another embodiment; 
         FIGS. 6A and 6B  are views illustrating expansion of the ice thermal storage pack of the ice thermal storage device in accordance with different embodiments; 
         FIG. 7  is a perspective view illustrating the ice thermal device in accordance with another embodiment; 
         FIG. 8  is a sectional view illustrating an ice thermal storage device in accordance with another embodiment; 
         FIG. 9A  is a perspective view illustrating an ice thermal storage device in accordance with a further embodiment; and 
         FIG. 9B  is a sectional view of the ice thermal storage device illustrated in  FIG. 9A . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
       FIG. 1  is a perspective view illustrating major components of a refrigerator in accordance with an embodiment. 
     As illustrated in  FIG. 1 , the refrigerator  1  includes a cabinet  10  defining a storage compartment  20 , and a door  30  to open or close the storage compartment  20 . 
     The door  30  is pivotally rotatable relative to the cabinet  10  to open or close the storage compartment  20 . To enable pivotal rotation of the door  30  relative to the cabinet  10 , a hinge  31  is coupled to at least one of upper and lower ends of the door  30 . 
     The storage compartment  20  is defined in the cabinet  10  and functions to keep food at a low temperature. There may be a plurality of storage compartments  20  as necessary. The plurality of storage compartments  20  is separated from one another by a partition  11  provided in the cabinet  10 . 
     A first storage container  50  and a second storage container  60  may be arranged in a lower region of the storage compartment  20  so as to provide separate storage spaces. The first and second storage containers  50  and  60  are slidable relative to the storage compartment  20 . 
     A shelf assembly  40  may be placed in the storage compartment  20  to divide the storage compartment  20  into a plurality of spaces. The shelf assembly  40  may be secured to, or be slidable relative to an inner wall of the storage compartment  20 . 
     Food stored in the storage compartment  20  is cooled by cold air generated from an evaporator (not shown). The cold air enables uniform cooling of food within the storage compartment  20 . Note that cold air has no ability to cool only specific food rapidly. 
     Accordingly, to enhance cooling efficiency of food stored in the storage compartment  20 , the refrigerator includes an ice thermal storage device  100  provided to come into contact with food. 
       FIG. 2  is a perspective view illustrating the shelf assembly of the refrigerator in accordance with the embodiment. 
     As illustrated in  FIG. 2 , the shelf assembly  40  includes a support frame  41  coupled to the inner wall of the storage compartment  20  and a shelf  42  fitted into the support frame  41 . 
     The inner wall of the storage compartment  20  is provided with a support structure  21  and the support frame  41  is provided with a mounting structure  44  corresponding to the support structure  21 . The support structure  21  may be a groove indented in the inner wall of the storage compartment  20  and the mounting structure  44  may be a protrusion corresponding to the groove. Of course, conversely, the support structure  21  may be a protrusion and the mounting structure  44  may be a corresponding groove. 
     The shelf  42  may be slidably fitted into the support frame  41 . As such, when attempting to take out food placed on the shelf  42 , the shelf  42  is pulled out so as to be slidably moved out of the storage compartment  20 . In this case, the support frame  41  is provided with a plurality of stoppers (not shown), realizing stepwise sliding movement of the shelf  42 . 
     The sliding movement of the shelf  42  out of the storage compartment  20  may cause food placed on the shelf  42  to fall rearward. To prevent this, the shelf  42  is provided at a rear end thereof with an anti-fall bar  43  having a predetermined height. 
     The ice thermal storage device  100  may be coupled to the shelf  42 . The shelf  42  may have a seating recess  45  having a shape corresponding to the ice thermal storage device  100  such that the ice thermal storage device  100  is seated in the seating recess  45 . Once the ice thermal storage device  100  is seated into the seating recess  45  and is coupled to the shelf  42 , food is placed on an upper surface of the ice thermal storage device  100 . As food comes into contact with the ice thermal storage device  100  having a relatively low temperature, efficient cooling of food may be possible. 
       FIG. 3  is an exploded perspective view illustrating the ice thermal storage device in accordance with the embodiment, and  FIG. 4A  is a sectional view of the ice thermal storage device in accordance with the embodiment. 
     As illustrated in  FIGS. 3 and 4A , the ice thermal storage device  100  includes an ice thermal storage pack  140  in which an ice thermal material  141  is sealed, and a case  101  in which the ice thermal storage pack  140  is received. 
     The ice thermal storage material  141  may be phase change material (PCM), which is in liquid phase at a room temperature and is changed to a solid phase at a temperature of the storage compartment  20  when the ice thermal storage device  100  is placed in the storage compartment  20  as illustrated in  FIG. 1 . The ice thermal storage material  141  may increase or decrease in volume while undergoing phase change from liquid to solid, or vice versa. For example, the ice thermal storage material  141  may be any one of water, a mixture of water and a PCM, and other aqueous solutions. The constituent components of the ice thermal storage material  141  may be determined based on the temperature of the storage compartment  20  illustrated in  FIG. 1 . 
     The ice thermal storage material  141  is sealed by an enclosure  142  surrounding the ice thermal storage material  141 . Since the ice thermal storage material  141  may increase or decrease in volume during phase change, the enclosure  142  is made of an elastic material to cope with the volume change of the ice thermal storage material  141 . For example, the enclosure  142  is made of a synthetic resin film, such as a polyethylene film. The ice thermal storage pack  140  may be fabricated by sandwiching the ice thermal storage material  141  between two synthetic resin films and attaching rims of the synthetic resin films. 
     To fix the ice thermal storage pack  140  within the case  101 , the ice thermal storage pack  140  may be provided with a fixing hole  143 . The fixing hole  143  may be located at a bonding region of the synthetic resin films and a plurality of fixing holes may be provided as necessary. 
     The case  101  includes a housing  102  in which the ice thermal storage pack  140  is received, and a heat transfer plate  130  coupled to the housing  102  so as to come into contact with the ice thermal storage pack  140 . 
     The housing  102  defines an external appearance of the ice thermal storage device  100 . The housing  102  may have a top opening in which the heat transfer plate  130  is located. The housing  102  may include a first housing  110  defining a bottom surface and a second housing  120  coupled to the first housing  110  to support the heat transfer plate  130  coupled thereto. 
     The rim of the first housing  110  may be bent upward to define a sidewall of the case  101 . An assembly groove  111  is formed in an upper end of the first housing  110 , and a lower end of the second housing  120  is configured so as to be fitted into the assembly groove  111 , enabling engagement of the first housing  110  and the second housing  120 . 
     The second housing  120  is provided with rails  121  to which the heat transfer plate  130  is slidably fitted. The rails  121  may be attached to an inner ceiling surface of the second housing  120  to extend in a longitudinal direction of the heat transfer plate  130  by a predetermined length. More particularly, two rails  121  may be provided to support opposite sides of the heat transfer plate  130  respectively. 
     The heat transfer plate  130  is located above the ice thermal storage pack  140  such that a lower surface of the heat transfer plate  130  comes into contact with the ice thermal storage pack  140 . The heat transfer plate  130  assists efficient heat-exchange between relative hot food and the relatively cold ice thermal storage pack  140 , which increases cooling efficiency of food. 
     Most heat transfer between the heat transfer plate  130  and the ice thermal storage pack  140  is performed by conduction and therefore, the greater the contact area between the heat transfer plate  130  and the ice thermal storage pack  140 , the greater the cooling efficiency of the heat transfer plate  130 . When the ice thermal storage material  141  within the ice thermal storage pack  140  is in liquid phase, the ice thermal storage pack  140  may be deformed in shape by external force. Thus, upon assembly of the case  101 , the heat transfer plate  130  is assembled to apply pressure to the ice thermal storage pack  140  such that the lower surface of the heat transfer plate  130  comes into contact with the upper surface of the ice thermal storage pack  140 . 
     The heat transfer plate  130  may be made of a metallic material and more particularly, a metal having high thermal conductivity and chemical stability against water. For example, the heat transfer plate  130  is made of an aluminum alloy. 
     A surface of the heat transfer plate  130  may be cooled to a temperature below zero, which may cause injury to a user hand when the user&#39;s hand touches the metallic heat transfer plate  130  when attempting to take out food. To prevent such injury, a coating layer (not shown) may be formed on an upper surface of the heat transfer plate  130  on which food is placed. The coating layer may be made of a general material used to coat a metallic surface. For example, fluorine coating or synthetic resin coating may be used. 
     In a state in which food is placed on the upper surface of the heat transfer plate  130 , the case  101  containing the heat transfer plate  130  receives load of food. To prevent deformation or damage to the case  101  by the load of the food, a load carrying member  112  is provided in the housing  102  to carry the load of the food applied to the heat transfer plate  130 . In consideration of the fact that the load of the food is applied downward, the load carrying member  112  is vertically installed such that a lower end thereof is fixed on an inner bottom surface of the housing  102  and an upper end thereof comes into contact with the heat transfer plate  130  to carry it. The load carrying member  112  may be formed integrally with the housing  102 . 
     The load carrying member  112  may extend in a longitudinal direction of the housing  102  to divide the interior space of the housing  102  into two spaces. Ice thermal storage packs  140  and  140 ′ may be arranged respectively in the spaces divided by the load carrying member  112 . 
     Support bars  113  and  114  may extend in a longitudinal direction of the ice thermal storage pack  140  to support lateral surfaces of the ice thermal storage pack  140 . The support bars  113  and  114  may be fixed on the inner bottom surface of the housing  102 . At least a part of the lateral surface of the ice thermal storage pack  140  does not come into contact with the corresponding support bar  113  or  114 , to enable formation of an expansion induction region  115  which will be described hereinafter. Specifically, upper ends of the support bars  113  and  114  are located lower than the upper surface of the ice thermal storage pack  140 . The support bars  113  and  114  may include a first support bar  113  and a second support bar  114  to support opposite lateral surfaces of the ice thermal storage pack  140 . 
     The housing  102  may be provided at the inner bottom surface thereof with a fixing pin  118  corresponding to the fixing hole  143 . As the fixing pin  118  is fastened into the fixing hole  143 , the ice thermal storage pack  140  may be kept at a fixed position. Note that a plurality of fixing pins  118  and a plurality of fixing holes  143  may be provided. 
     The expansion induction region  115  is defined between the upper ends of the support bars  113  and  114  and the inner ceiling surface of the case  101 . The expansion induction region  115  extends in a longitudinal direction of the support bars  113  and  114  along the upper ends of the support bars  113  and  114 . When the ice thermal storage material  141  undergoes phase change from liquid to solid and the volume of the ice thermal storage pack  140  increases, a portion of the ice thermal storage pack  140  supported by the support bars  113  and  114  is limited in expansion and therefore, the remaining lateral surfaces of the ice thermal storage pack  140  not supported by the support bars  113  and  114  may expand in a longitudinal direction of the heat transfer plate  130  into the expansion induction region  115 . Allowing expansion of only a part of the ice thermal storage pack  140  into the expansion induction region  115  other than the entire lateral surface of the ice thermal storage pack  140  may assure that the lower surface of the heat transfer plate  130  continuously comes into close contact with the upper surface of the ice thermal storage pack  140 . As such, high cooling efficiency may be maintained even if the ice thermal storage pack  140  is deformed due to phase change of the ice thermal storage material  141 . 
       FIG. 4B  is a sectional view of the ice thermal storage device in accordance with another embodiment, and  FIG. 4C  is a sectional view of the ice thermal device in accordance with another embodiment. 
     Variation in the volume of the ice thermal storage material  141  may cause the enclosure of the ice thermal storage material  141  to break due to pressure applied from the ice thermal storage material  141 . To prevent breakage of the enclosure  142 , a predetermined quantity of air may be present in the form of bubbles within the ice thermal storage pack  140  along with the ice thermal storage material  141 . The air tends to be reduced in volume when the volume of the ice thermal storage material  141  increases via phase change to a solid. Such a reduction in the volume of the air may offset the increase in the volume of the ice thermal storage material  141  even if the volume of the ice thermal storage pack  140  does not increase. As such, the air acts to reduce pressure applied to the enclosure  142  by the ice thermal storage material  141 , preventing breakage of the enclosure  142 . 
     The air has a lower density than the ice thermal storage material  141  and may be located above the ice thermal storage material  141  within the ice thermal storage pack  140 . Also, the air has a lower thermal conductivity than the heat transfer plate  130  and may deteriorate heat transfer between the ice thermal storage material  141  and the heat transfer plate  130 . 
     An air-bubble guide region  116  is provided to guide upward expansion of an upper edge of the ice thermal storage pack  140 . The air, which has a lower density than the ice thermal storage material  141 , may be collected in the air-bubble guide region  116 . The air-bubble guide region  116  may be provided near the expansion induction region  115 . 
     The air-bubble guide region  116  may be provided between the upper edge of the ice thermal storage pack  140  and the heat transfer plate as illustrated in  FIG. 4B , or may be provided between the upper edge of the ice thermal storage pack  140  and the housing  102  as illustrated in  FIG. 4C . 
       FIG. 5  is a sectional view of an ice thermal storage device in accordance with another embodiment. 
     As illustrated in  FIG. 5 , the ice thermal storage device  200  includes an ice thermal storage pack  240 , a first heat transfer plate  230   a  and a second heat transfer plate  230   b  arranged to come into contact with upper and lower surfaces of the ice thermal storage pack  240  respectively, and a housing  210  to which the first heat transfer plate  230   a  and the second heat transfer plate  230   b  are coupled. 
     The housing  210  may be provided with rails  211   a  and  211   b  for coupling of the first and second heat transfer plates  230   a  and  230   b . The first heat transfer plate  230   a  and the second heat transfer plate  230   b  are slidably fitted into the respective rails  211   a  and  211   b . The first heat transfer plate  230   a  and the second heat transfer plate  230   b  may have the same configuration as the heat transfer plate  130  illustrated in  FIGS. 3 and 4A . 
     Support bars  213  and  214  and a load carrying member  212  may be secured to the housing  210  to extend between opposite inner wall surfaces of the housing  210 . 
     The ice thermal storage device  200  may perform heat transfer through upper and lower sides thereof. Food located on the first heat transfer plate  230   a  may be directly cooled by coming into contact with the first heat transfer plate  230   a , whereas food located below the second heat transfer plate  230   b  may be indirectly cooled by cold air which is generated by heat exchange with the second heat transfer plate  230   b.    
       FIGS. 6A and 6B  are views illustrating expansion of the ice thermal storage pack included in the ice thermal storage device in accordance with different embodiments. 
     The ice thermal storage material  141  illustrated in  FIG. 6A  is in liquid phase. The ice thermal storage pack  140  is supported at opposite sides thereof by the first support bar  113  and the second support bar  114 . Air  144 , which is present in the ice thermal storage pack  140  along with the ice thermal storage material  141 , occupies an upper interior space of the ice thermal storage pack  140 . The volume of the ice thermal storage material  141  expands if the ice thermal storage material  141  is changed to a solid phase under the influence of the surrounding low temperature. 
     The ice thermal storage material  141  illustrated in  FIG. 6B  is in a solid phase. Expansion of a portion of the ice thermal storage pack  140  in contact with the support bars  113  and  114  is limited, which causes the ice thermal storage pack  140  to be expanded into the expansion induction region  115 . In this case, the ice thermal storage pack  140  may maintain constant contact with the heat transfer plate  130 . In addition, since the air  144  present in the ice thermal storage pack  140  is likely to be collected into the air-bubble guide region  116  during expansion of the ice thermal storage pack  140 , it may be possible to prevent the air  144  from hindering heat transfer between the heat transfer plate  130  and the ice thermal storage material  141 . 
       FIG. 7  is a perspective view illustrating the ice thermal device in accordance with another embodiment. 
     As illustrated in  FIG. 7 , the ice thermal storage device  100  may be mounted in the storage compartment  20 . 
     The inner wall of the storage compartment  20  is provided with the support structure  21  and the ice thermal storage device  100  is externally provided with a mounting structure  117  corresponding to the support structure  21 . The support structure  21  may be a groove indented in the inner wall of the storage compartment  20  and the mounting structure  117  may be a protrusion corresponding to the groove. Of course, conversely, the support structure  21  may be a protrusion and the mounting structure  117  may be a corresponding groove. 
     The ice thermal storage device  200  illustrated in  FIG. 5  may be mounted in the storage compartment  20  in the same manner. 
       FIG. 8  is a sectional view illustrating an ice thermal storage device in accordance with another embodiment. 
     As illustrated in  FIG. 8 , the first storage container  50  may have a bottom opening  51  and a seating recess  52  around the opening  51 . The second storage container  60  may have a top opening  61 . 
     The ice thermal storage device  200  may be provided at an outer periphery thereof with a seating protrusion  217  having a shape corresponding to that of the seating recess  52 . As the seating protrusion  217  is fitted into the seating recess  52 , the ice thermal storage device  200  is mounted to the first storage container  50 . 
     Food received in the first storage container  50  above the first heat transfer plate  230   a  may be cooled by the ice thermal storage pack  240 . Food received in the second storage container  60  may be indirectly cooled as interior cold air of the second storage container  60  is cooled by a lower surface of the second heat transfer plate  230   b.    
       FIG. 9A  is a perspective view illustrating an ice thermal storage device in accordance with a further embodiment, and  FIG. 9B  is a sectional view of the ice thermal storage device illustrated in  FIG. 9A . 
     As illustrated in  FIGS. 9A and 9B , an ice thermal storage device  300  includes an ice thermal storage pack  340 , a heat transfer plate  330  arranged to come into contact with the ice thermal storage pack  340 , a first housing  310  in which the ice thermal storage pack  340  is received, and a second housing  320  coupled to the first housing  310 . 
     The ice thermal storage pack  340  is identical to the ice thermal storage pack  140  illustrated in  FIG. 3 . In addition, the ice thermal storage pack  340  is fixed to the first housing  310  in the same method as that as illustrated in  FIG. 3 . 
     The first housing  310  is provided at corners thereof with upwardly-protruding fastening pieces  319 . To correspond to the respective fastening pieces  319 , the heat transfer plate  330  is provided with fastening holes  331  and the second housing  320  is provided with fastening recesses  322 . The heat transfer plate  330  may be secured to the top of the first housing  310  as the fastening pieces  319  penetrate the fastening holes  331 . Then, the second housing  320  may be coupled to the first housing  310  as the fastening pieces  319  are inserted into the fastening recesses  322  and simultaneously, may apply pressure to the heat transfer plate  330  so as to secure the heat transfer plate  330 . As such, the heat transfer plate  330  and the second housing  320  are successively coupled using the fastening pieces  319 , which results in easy assembly and simplified manufacture of the ice thermal storage device  300 . 
     As is apparent from the above description, according to one embodiment, an ice thermal storage pack usable with a refrigerator is configured to maintain constant contact with a heat transfer plate even if the volume of the ice thermal storage pack increases due to phase change of an ice thermal storage material sealed in the ice thermal storage pack. The ice thermal storage pack has the effect of continuously maintaining cooling efficiency of food. Further, the ice thermal storage pack is received in a case that protects the ice thermal storage pack from external shock, having no risk of breakage. 
     Furthermore, even if the ice thermal storage pack breaks within the case, the case prevents leakage of the ice thermal storage pack, which prevents damage to food due to the leakage of the ice thermal storage pack. 
     Although the embodiment has been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.