Abstract:
In order to accomplish the objective of the present invention, according to one embodiment of the present invention, an apparatus for storing ice comprises: a housing which has heat insulation characteristics and the interior of which has a storage space; an ice maker which is accommodated in the housing, and which contains an ice tray for making ice; an ice bin arranged below the ice maker to store the ice made by the ice maker; a transfer member arranged within the ice bin to discharge the ice to the outside of the ice bin; a refrigerating cycle which extends into the housing, and which includes an evaporation unit attached to the outer surface of the ice tray to cool the ice tray; and a control unit which controls the operation of the refrigerating cycle and of the transfer member. Air in the storage space is directly cooled by being in contact with the evaporation unit and/or the ice tray, and the control unit operates the refrigerating cycle to cool the storage space when the temperature of the ice tray and/or of the evaporation unit becomes higher than a preset temperature (Ta).

Description:
DESCRIPTION  
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to an apparatus for storing an ice and a method for controlling the same. 
         [0003]    2. Background Art 
         [0004]    In general, in case of wafer purifiers which are capable of dispensing an ice or commercial ice making apparatus, a direction cooling type ice making system and an ice storage system are adopted. 
         [0005]    In case of the direct cooling type ice making system and the ice storage system, an ice may be made by using a refrigerant tube extending along an outer surface of an ice tray. Furthermore, an ice storage space in which the ice tray is received may be cooled through the heat-exchange between the refrigerant tube and the ice tray. Thus, even though an ice making process is not performed, a refrigerating cycle operation should be performed to circulate a refrigerant along the refrigerant tube extending along the outer surface of the ice tray. 
         [0006]    In this case, moisture within the storage space may be frozen on the refrigerant tube and the outer surface of the ice tray. As a result, the refrigerant and cool air within the storage space are not smoothly heat-exchanged with each other. Thus, the heat-exchange performance between the ice tray and the refrigerant tube may be gradually reduced. Therefore, it may be impossible to control a temperature of the storage space. 
         [0007]    In addition, ice making performance may be reduced due to the reduction of the heat-exchange performance between the refrigerant tube and the ice tray. 
       DISCLOSURE OF THE INVENTION 
     Technical Problem 
       [0008]    Embodiments provide an ice storage apparatus in which an operation time of a refrigerating cycle for cooling an ice making space is controlled to prevent an ice tray and a refrigerant tube from being frozen in a refrigerating system for cooling a storage space by using the refrigerating pipe mounted on the ice tray and a method for controlling the same. 
         [0009]    Embodiments also provide an ice tray structure for sufficiently heat-exchanging cool air transferred from a refrigerant tube with air within a storage space and a structure which is capable of treating defrosted water dropping down from an outer surface of the ice tray. 
       Technical Solution 
       [0010]    In one embodiment, an ice storage apparatus includes: a housing having a heat insulation characteristic, the housing having a storage space therein; an ice maker received within the housing, the ice maker including an ice tray for making ices; an ice bin disposed under the ice maker to store the ices made in the ice maker; a transfer member disposed within the ice bin to discharge the ices to the outside of the ice bin; a refrigerating cycle extends into the housing, the refrigerating cycle, the refrigerating cycle including an evaporation unit attached to an outer surface of the ice tray to cool the ice tray; and a control unit for controlling operations of the refrigerating cycle and the transfer member, wherein air within the storage space is directly cooled by contacting the evaporation unit and/or the ice tray, and the control unit operates the refrigerating cycle to cool the storage space when the ice tray and/or the evaporation unit have/has a temperature greater than a set temperature (Ta). 
         [0011]    In another embodiment, a method for controlling an ice storage apparatus including a housing defining a storage space, an ice tray received within the housing, and an evaporation unit attached to an outer surface of the ice tray, wherein the ice tray and the evaporation unit directly contact air within the housing to cool the storage space includes: cooling the ice tray after a surface temperature of the ice tray and/or the evaporation unit reach a set temperature (Ta) even though the temperature of the storage space is increased to a temperature greater than the set temperature (Ta) at which the cooling is required. 
       Advantageous Effects 
       [0012]    The ice storage apparatus including the above-described components and the method for controlling the same according to the embodiments may have following effects. 
         [0013]    First, the ice storage apparatus using the direct type cooling method in which the evaporation unit and/or the ice tray are/is directly heat-exchanged with the air within the refrigerator, even though the air within the refrigerator is greater than the set temperature, the refrigerating cycle may be operated after the evaporation and/or the ice tray has/have surface temperature(s) greater than the set temperature to completely remove the ices attached to the ice tray and the evaporation unit. 
         [0014]    Second, since the ices attached to the ice tray and the evaporation unit are completely removed after the inside of the refrigerator is cooled, the heat exchange efficiency between the ice tray and/or evaporation unit and the air within the storage space may be improved. 
         [0015]    Third, the ice tray may be expanded in area to reduce a time taken for cooling the air within the storage space, thereby reducing the power consumption. 
         [0016]    Third, since the defrosted water tray for receiving the defrosted water generated when the ices attached to the ice tray and the evaporation unit are melted is separately provided, the humidity within the storage space may be maintained at a low level. 
         [0017]    Fourth, since the humidity within the storage space is maintained at the low level, the phenomenon in which the surfaces of the ice tray and the evaporation unit are frozen may be reduced. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a perspective view illustrating an outer appearance of a water purifier according to an embodiment. 
           [0019]      FIG. 2  is a perspective view illustrating an outer appearance of an ice making assembly disposed within the water purifier according to an embodiment. 
           [0020]      FIG. 3  is a perspective view illustrating an inner structure of the ice making assembly in a state where a housing defining an outer appearance of the ice making assembly is removed. 
           [0021]      FIG. 4  is a longitudinal sectional view taken along line I-I of  FIG. 2 . 
           [0022]      FIG. 5  is a schematic cross-sectional view illustrating the inner structure of the ice making assembly according to an embodiment. 
           [0023]      FIG. 6  is a perspective view of an ice maker according to an embodiment. 
           [0024]      FIG. 7  is a flowchart illustrating a process for controlling a refrigerating device according to an embodiment. 
           [0025]      FIG. 8  is an exploded perspective view illustrating a structure of an ice maker for improving cooling efficiency according to another embodiment. 
           [0026]      FIG. 9  is a perspective view illustrating a structure of an ice maker according to another embodiment. 
           [0027]      FIG. 10  is a cross-sectional view taken along line II-II of  FIG. 9 . 
       
    
    
     MODE FOR CARRYING OUT THE INVENTION 
       [0028]    Hereinafter, an ice storage apparatus and a method for controlling the same according to embodiments will be described in detail with reference to the accompanying drawings. A water purifier having ice generation and storage functions will be described as an example. However, the present disclosure is not limited to the water purifier having the ice making function. For example, various apparatuses which make and store ices and include a storage space for storing the made ices such as refrigerators or freezers may be applied to the current embodiments. 
         [0029]      FIG. 1  is a perspective view illustrating an outer appearance of a water purifier according to an embodiment. 
         [0030]    Referring to  FIG. 1 , a water purifier  10  according to an embodiment includes a cabinet  11  and a front cover  12  coupled to an opened front surface of the cabinet  11 . Here, an outer appearance of a main body of the water purifier  10  may be defined by the cabinet  11  and the front cover  12 . Also, units for supplying purified water, cool water, hot water, and ices may be disposed within the main body defined by the cabinet  11  and the front cover  12 . For example, a refrigerating cycle for making ices, a heating unit for generating hot water, a filter member for purifying water, an ice compartment for making and storing ices, a water tank for storing water, and a pump for pumping the water stored in the water tank may be received within the main body. Also, the refrigerating cycle includes a compressor, a condenser, an expansion member, and an evaporator. 
         [0031]    A control panel  13  including a button part for inputting various functions and an operation command and a display part for displaying an operation state of the water purifier  10  is disposed on one side of a front surface of the front cover  12 . Also, a dispenser  20  for dispensing water or ices is disposed in the front surface of the front cover  12 . 
         [0032]    In detail, the dispenser  20  includes a receiving part for receiving a container in which water or an ice is received. The receiving part is recessed backward from the front surface of the front cover  12  by a predetermined depth. Also, the dispenser  20  includes an ice chute  21  extending from a top surface of the recessed portion to guide discharge of the ices and a water chute  23  extending to guide dispensing of water. The dispenser  20  further includes an ice button  22  and a water button  23  which are disposed on a rear surface of the recessed portion to input an ice dispensing command and a water dispensing command, respectively. Also, the dispenser  20  further includes a residual water drain  24  disposed in the bottom of the recessed portion to receive residual water. 
         [0033]    Various parts for making, storing, and dispensing ices are received within the main body of the water purifier  10 . The parts are disposed in an upper portion of the main body of the water purifier  10 . Hereinafter, the units for making, storing, and supplying ices in the water purifier  10  will be described with reference to the accompanying drawings. 
         [0034]      FIG. 2  is a perspective view illustrating an outer appearance of an ice making assembly disposed within the water purifier according to an embodiment.  FIG. 3  is a perspective view illustrating an inner structure of the ice making assembly in a state where a housing defining an outer appearance of the ice making assembly is removed.  FIG. 4  is a longitudinal sectional view taken along line I-I of  FIG. 2 . 
         [0035]    Referring to  FIG. 2 , an ice making assembly  30  according to an embodiment may include an ice making part A for making ices, an ice storage part B for storing the ices made in the ice making part A, and a water storage part C for storing cool water. 
         [0036]    In detail, an outer appearance of the ice making assembly  30  may be defined by a housing  31 . Also, the ice making assembly  30  may have an approximately hexahedral shape. 
         [0037]    Also, parts for making ices, storing the made ices, and storing water are disposed within the housing  31 . A heat insulation layer may be provided within the housing  31  to improve a heat insulation characteristic. As shown in  FIG. 2 , an ice separation motor assembly  322 , a transfer motor assembly  373 , and a damper  35  may protrude outward from the housing  31 . The ice separation motor assembly  322  is configured to separate made ices from an ice making container, and the transfer motor assembly  373  is configured to transfer the ices stored in the ice storage part B to the outside. Also, the ices stored in the ice storage part B may be selectively dispensed to the outside through the ice chute  21  by selectively opening or closing the damper  35 . 
         [0038]    Referring to  FIGS. 3 and 4 , the ice making part A includes an ice maker  32  for making ices. Also, the ice storage part B includes an ice bin  33  for storing the ices made in the ice maker  32  and a transfer member  37  for transferring the ices stored in the ice bin  33  to the outside. Also, the water storage part C includes a cool water tank  36  in which the ices stored in the ice bin  33  are putted to store cool water having a low temperature. When a user pushes the cool water button, the water stored in the cool water tank  36  may be dispensed. 
         [0039]    In detail, the ice maker  32  includes an ice tray  321  partitioned into a plurality of spaces, each having a size corresponding to that of an ice to be made to store water for making ices, an ice separation unit for drawing up the ices stored in the ice tray  321  to drop into the ice bin  33 , and the ice separation motor assembly  322  for driving the ice separation unit. The ice separation unit includes an ice separation shaft (see reference numeral  324  of  FIG. 6 ) rotated by the ice separation motor assembly  322  and an ejector (see reference numeral  325  of  FIG. 6 ) protruding from an outer surface of the ice separation shaft  324  to draw up the ices made in the partitioned spaces of the ice tray  321 . 
         [0040]    Also, the transfer member  37  includes a transfer shaft  371 , the transfer motor assembly  373  for rotating the transfer shaft  371 , an auger  372  wound spirally or helically around an outer surface of the transfer shaft  371  to push ices; and an opening/closing wall  333  integrally coupled to the transfer shaft  371  at a position corresponding to an end of the auger  372 . 
         [0041]    The ice bin  33  has an opened top surface. Thus, ices made in the ice tray  321  may drop into the ice bin  33  through the opened top surface of the ice bin  33 . Also, a first discharge hole  331  for dispensing ices is defined in one surface of the ice bin  33 . Also, a discharge duct  34  for guiding the discharge of ices is connected to the first discharge hole  331 . The damper  35  is rotatably coupled to a discharge end of the discharge duct  34 . Also, the ice chute  21  is connected to a discharge side of the discharge duct  34  to communicate with the discharge duct  34 . Thus, the ices discharged through the first discharge hole  331  are moved along the discharge duct  34 . Also, the ices guided into the discharge duct  34  by opening the damper  35  are discharged to the outside of the water purifier through the ice chute  21 . Also, a shutter  38  rotated at a predetermined angle in a state where the shutter  38  is closely attached to an outer surface of the ice bin  33  is disposed on the first discharge hole  331 . The shutter  38  may be rotated by an opening/closing motor  381  which is forwardly or backwardly rotatable. 
         [0042]    Also, a second discharge hole  332  through ice to be supplied into the cool water tank  36  are discharged is defined in a bottom surface of a rear side of the ice bin  33  disposed opposite to the position in which the first discharge hole  331  is defined. In detail, the second discharge hole  332  may be opened toward the cool water tank  36 . 
         [0043]    Also, the opening/closing wall  333  integrally coupled to the outer surface of the transfer shaft  371  may have a cylindrical shape. One surface of the opening/closing wall  333  having the cylindrical shape, i.e., a surface of the opening/closing wall  333  facing the auger  372  may be opened, and an opposite surface may be closed. The a through hole  333   a  having a predetermined size is define din the closed surface. The through hole  333   a  may have various shapes. For example, the through hole  333   a  may have a fan shape. As the transfer shaft  371  is rotated, the auger  372  and the opening/closing wall  333  may be rotated together. When the transfer shaft  371  is rotated at an angle at which the through hole  333   a  is disposed at the bottom side of the ice bin  33 , ices pressed by the auger  372  may be discharged through the through hole  333   a.  Also, the ices discharged through the through hole  333   a  drop into the cool water tank  36  through the second discharge hole  332 . 
         [0044]    The cool water tank  36  may be a tank having a predetermined volume and a hexahedral shape. An inlet port  361  through which ices are received may protrude from a top surface of the cool water tank  36 . The inlet port  361  may be disposed directly under the second discharge hole  332 . Also, as shown in  FIGS. 3 and 4 , the inlet port  361  may have a rib shape extending from the top surface of the cool water tank  36  by a predetermined length. Also, the inlet port  361  may have a circular, non-circular, or polygonal shape in section. 
         [0045]    The ice maker  32 , the ice bin  33 , and the cool water tank  36  are received in a single storage space  300  defined by the housing  31 . Also, the storage space  300  may be maintained in a low temperature state, e.g., at a temperature of about 3° C. by an evaporation unit (see reference numeral  54  of  FIG. 5 ) extending from a bottom surface of the ice tray  321 . The evaporation unit represents a refrigerant tube in which a low-temperature low-pressure two-phase refrigerant passing through an expansion member flows. 
         [0046]    Also, a supply tube  41  for supplying purified water into the cool water tank  36  and a discharge tube  42  for discharging the water stored in the cool water tank  36  may pass through the bottom surface of the housing  31  to communicate with the bottom surface of the cool water tank  36 . 
         [0047]    Functions of the ice making assembly  30  having the above-described structure will be simply described. 
         [0048]    First, to maintain water stored in the cool water tank  36  in a cool water state having a temperature less than room temperature, the ices stored in the ice bin  33  should be supplied into the cool water tank  36 . For this, the transfer shaft  371  is rotated in one direction, and thus, the auger  372  is rotated together with the transfer shaft  371  to push ices toward the through hole  333   a.  Thus, the ices stored in the ice bin  33  are discharged through the through hole  333   a  and the second discharge hole. Then, the discharged ices drop into the cool water tank  36  through the inlet port  361  of the cool water tank  36 . 
         [0049]    On the other hand, when the user inputs the ice dispensing command, the transfer motor  371  is reversely rotated. Thus, the ices stored in the ice bin  33  are guided toward the first discharge hole  331  by the auger  372 . Also, the ices guided into the first discharge hole  331  are discharged into the dispenser  20  through the discharge duct and the ice chute  21 . Here, when the ice dispensing command is not inputted, the first discharge hole  331  is closed by the shutter  38 , and a discharge hole of the discharge duct  34  is closed by the damper  35 . Thus, it may completely prevent external air from being introduced into the housing  31 . 
         [0050]      FIG. 5  is a schematic cross-sectional view illustrating the inner structure of the ice making assembly according to an embodiment.  FIG. 6  is a perspective view of an ice maker according to an embodiment. 
         [0051]    Referring to  FIGS. 5 and 6 , the refrigerating cycle is installed to freeze water supplied into the ice tray  321 . In detail, the refrigerating cycle includes a compression unit  51  for compressing a refrigerant, a condensation unit  52  for condensing the refrigerant compressed by the compression unit  51 , an expansion unit  53  for expanding the refrigerant passing through the condensation unit  52  into a low-temperature low-pressure two-phase refrigerant state, and an evaporation unit  54  for heat-exchanging the refrigerant passing through the expansion unit  53  with cool air within the housing  31 . 
         [0052]    The evaporation unit  54  may be a portion of the refrigerant tube connecting the refrigerating cycle to each other to form a close loop shape. The evaporation unit  54  may be bent at least one time on the bottom surface of the ice tray  321 . The inside of the ice tray  321  may be partitioned into a plurality of ice making spaces by a plurality of partition walls. Also, the ice separation shaft  324  extends in a length direction of the ice tray  321  above the ice tray  321 . Also, a plurality of ejectors  325  protrude from an outer surface of the ice separation shaft  324 . The ejectors  325  are disposed in the ice making spaces defined by the ice tray  321 , respectively. Thus, as the ice separation shaft  324  is rotated, the ejectors may be rotated together to draw up ices made in the ice tray  321 . 
         [0053]    Also, a tray temperature sensor  60  is disposed on the outer surface of the ice tray  321  to detect a surface temperature of the ice tray  321 . Also, an ice making completion time point may be determined according to the surface temperature of the ice tray  321 . 
         [0054]    Also, the ice separation motor assembly  333  is connected to an end of the ice separation shaft  324 . According to products, a gear box  323  may be disposed between the ice separation motor assembly  322  and the ice separation shaft  324 . That is, a rotation force generated by the ice separation motor assembly  322  may be indirectly transmitted into the ice separation shaft  324  through the gear box  323 . The gear box  323  may be a deceleration gear assembly for reducing the rotation number of the ice separation motor assembly  322 . 
         [0055]    The ice tray  321 , the ice bin  33  disposed under the ice tray  321 , and the cool water tank  36  disposed under the ice bin  33  are received in the storage space  300  defined by the housing  31 . Also, a refrigerator temperature sensor  55  may be disposed on a side of an inner surface of the housing  31  to detect an internal temperature of the storage space  300 . 
         [0056]    Also, the storage space  300  may be maintained at a predetermined temperature, e.g., a temperature of about 3° C. This may be possible by heat-exchanging the evaporation unit  54  mounted on the bottom surface of the ice tray  321  with air within the storage space  300 . In detail, a direct ice making method in which ices are made by heat-exchanging the evaporation unit  54  with water supplied into the ice tray  321 , but not an indirect ice making method in which the water supplied into the ice tray  321  is converted into ices by cool air within the storage space  300  may be adopted. Also, the temperature of the storage space  300  may be maintained through a direct cooling method in which the evaporation unit is directly heat-exchanged with air within the storage space  300 , but not an indirect cooling method in which cool air is supplied into the storage space  300  to cool the storage space  300 . 
         [0057]    In case of a general ice making water purifier, when an ice making process is finished in the ice maker  32 , an operation of the refrigerating cycle is stopped. However, in the current embodiment, although an ice making process is finished in the ice maker  32 , the operation of the refrigerating cycle may be continuously performed in a case where the temperature of the storage space  300  is greater than a set temperature. That is to say, to decrease the temperature of the storage space  300  to the set temperature or less, the ice tray  321  may be continuously cooled in a state where the ice tray  321  is empty. Thus, the evaporation unit  54  and the air within the storage space may be heat-exchanged, and also, the ice tray  321  and the air within the storage space may be heat-exchanged. Also, when the temperature of the storage space  300  is decreased to the set temperature or less, the operation of the refrigerating cycle may be stopped. 
         [0058]    According to the above-described operation method, moisture contained in the air within the storage space  300  may be condensed while the storage space  300  is cooled. Thus, a surface of the ice tray  321  and a surface of the evaporation unit  54  may be frozen. Also, as a time elapses, an ice accumulated on the ice tray  321  and the evaporation unit  54  may be thicker. As a result, the heat-exchange between the evaporation unit  54  and the air within the storage space  300  and between the ice tray and the air may not be smoothly performed. 
         [0059]    To prevent the heat exchange performance from being deteriorated by the ice attached to the surfaces of the ice tray  321  and the evaporation unit  54 , a control method according to an embodiment is proposed. Hereinafter, the control method will be described in detail with reference to the flowchart of  FIG. 7 . 
         [0060]      FIG. 7  is a flowchart illustrating a process for controlling a refrigerating device according to an embodiment. 
         [0061]    Hereinafter, the direct cooling method in which the evaporation unit  54 , the ice tray  321  mounted on the evaporation unit  54 , and the air within the storage space directly contact each other to perform the heat exchange therebetween may be described as the control method for the cooling device. 
         [0062]    To present the heat exchange performance from being deteriorated by the above-described freezing, the following control method may be applied. 
         [0063]    First, since ice making process is completed, and a storage space  300  is maintained to a set temperature, a control process starts in a state where cooling of the ice tray  321  is stopped (S 11 ), i.e., an operation of a refrigerating cycle is stopped. 
         [0064]    A refrigerator temperature sensor  55  installed in the storage space  300  detects a temperature of a refrigerator in real-time or periodically to determine whether a storage space temperature T 1  is greater than a set temperature Ta (S 12 ). In the strict sense, a control unit may determine whether a temperature of the storage space is greater than a set temperature. If the storage space temperature T 1  is less than the set temperature Ta, the refrigerating cycle is maintained in a stopped state. On the other hand, if it is determined that the storage space temperature T 1  is greater than the set temperature Ta, a tray temperature sensor  60  mounted on the ice tray  321  detects a temperature of the ice tray  321  (S 13 ). When it is determined that the ice tray temperature T 2  is greater than the set temperature Ta, the ice tray  321  is cooled. That is, a refrigerating cycle is operated to supply low-temperature cool air into an evaporation unit  54 . 
         [0065]    On the other hand, when it is determined that the temperature of the ice tray  321  is less than the set temperature Ta, the refrigerating cycle is maintained as ever in the stopped state. That is to say, even though the temperature of the storage space  300  is greater than the set temperature Ta, when the temperature of the ice tray  321  is less than the set temperature Ta, the refrigerating cycle is not operated. The reason is as follows. 
         [0066]    Although it is need to perform a cooling operation because the temperature of the storage space  300  is greater than the set temperature Ta, if an ice attached to the ice tray  321  is not melted and thus separated, cooling efficiency may be deteriorated to increase power consumption. Thus, the refrigerating cycle is operated after a wait until a surface temperature of the ice tray  321  is greater than the set temperature Ta. Here, the control unit may be programmed so that the operation of the refrigerating cycle is delayed until the surface temperature of the evaporation unit  54  as well as the ice tray  321  is greater than the set temperature Ta. Here, the set temperature Ta may represent a temperature enough to melt and separate the ice attached to the surface of the ice tray  321 , for example, a temperature of about 3° C. to about 4° C. 
         [0067]    When it is determined that the ice tray temperature T 2  is greater than the set temperature Ta, the refrigerating cycle is operated to cool the ice tray  321  (S 15 ). Also, it is determined whether the storage space temperature T 1  is less than a set temperature Tb (S 16 ). When this condition is satisfied, the operation of the refrigerating cycle is stopped to stop the cooling of the ice tray  321  (S 17 ). 
         [0068]    According to the above-described control method, to improve the cooling efficiency of the storage space, since the refrigerating cycle is operated after the ice attached to the surface of the ice tray  321  and/or the evaporation unit  54  is removed, the time taken for cooling the storage space  300  to the set temperature may be reduced. 
         [0069]      FIG. 8  is an exploded perspective view illustrating a structure of an ice maker for improving cooling efficiency according to another embodiment. 
         [0070]    Referring to  FIG. 8 , a structure of the ice tray  321  may be improved to improve the heat exchange efficiency in an ice storage apparatus to which the direct cooling method is applied. 
         [0071]    In detail, an ice maker may include an ice tray  321 , an ice separation heater  65  mounted on a bottom surface of the ice tray  321 , an evaporation unit  54  mounted under the ice separation heater  65 . Also, the evaporation unit  54  may be fixed by a separate bracket  66 . The ice separation heater  65  may be mounted between a top surface of the bracket  66  and the bottom surface of the ice tray  321 . When the bracket  66  is coupled to the bottom surface of the ice tray  321 , the ice separation heater  65  is seated on the top surface of the bracket  66 , and the evaporation unit  54  is fixed to the bottom surface of the bracket  66 . The bracket  66  may be formed of a metal member having superior thermal conductivity to quickly transfer cool air from the evaporation unit  54  toward the ice tray  321 . 
         [0072]    A heat transfer unit  326  for heat-exchanging may be disposed on a side of the ice tray  321 . For example, as shown in  FIG. 8 , the heat transfer unit  326  may be disposed on a rear surface of the ice tray  321 , i.e., a surface of the ice tray  321  fixed to an inner surface of the housing  31 . 
         [0073]    The heat transfer unit  326  may include a heat transfer plate  326   a  extending upward from an upper end of the rear surface of the ice tray  321  by a predetermined length and a plurality of heat transfer fins protruding from a rear surface of the heat transfer plate  326   b.    
         [0074]    As described above, the ice tray  321  may be increased in surface area, and also, the heat transfer fins may be disposed on the extension portion of the ice tray  321 . Thus, a contact area between the cool air transferred from the evaporation unit  54  toward the ice tray  321  and internal air of a storage space  300  may be increased. As the contact area is increased, a heat-exchange time may be reduced, and a heat-exchange amount may be increased. 
         [0075]      FIG. 9  is a perspective view illustrating a structure of an ice maker according to another embodiment.  FIG. 10  is a cross-sectional view taken along line II-II of  FIG. 9 . 
         [0076]    Referring to  FIGS. 9 and 10 , the current embodiment provides a defrosted water tray  70  for receiving defrosted water generated when ices attached to surfaces of an ice tray  321  and an evaporation unit  54  are melted. 
         [0077]    According to the control algorithm as described with reference to  FIG. 7 , the ices attached to the surfaces of the ice tray  321  and the evaporation unit  54  may be melted to generate the defrosted water. The defrosted water may cause a phenomenon in which the defrosted water drops onto ices stored in an ice bin  33  to melt and congeal the ices. In addition, when the defrosted water is evaporated, humidity within the storage space  300  may be increased. Thus, during the cooling operation process, the defrosted water may be frozen on the ice tray  321  and the evaporation unit  54 . Thus, to prevent the ice from being congealed with each other and humidity within a refrigerator from being increased, it may be necessary to install the separate defrosted water tray  70 . 
         [0078]    In detail, the defrosted water tray  70  may be mounted on the bottom surface of the ice tray  321 . Also, the defrosted water tray  70  has a bottom part  71  and a wall part  72  extending upward from the bottom part  71  to provide a volume for storing the defrosted water having a predetermined amount. Also, the bottom part  71  may be inclined toward an edge of any side to smoothly drain the defrosted water. Also, a drain hole  73  may be defined in one side of the bottom part  71 , i.e., the lowest portion of the inclined surface of the bottom part  71 . Although not shown, a drain hose may be connected to the drain hole  73 . The drain hose may extend to the outside of an ice making assembly  30 . 
         [0079]    According to the above-described structure, the defrosted water melted to drop down from the ice tray  321  and the evaporation unit  54  may be collected into the defrosted water tray  70 . Also, the defrosted water collected into the defrosted water tray  70  may be discharged to the outside. Thus, the humidity within the storage space  300  may be maintained at a low level to prevent an ice from being attached to the ice tray  321  and the evaporation unit  54 .