Patent Publication Number: US-2021190407-A1

Title: Refrigerator and control method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2019-0174047, filed on Dec. 24, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
     BACKGROUND 
     Field 
     Apparatuses and methods consistent with the disclosure relate to a refrigerator, and more particularly, to a refrigerator having an improved heater structure to prevent a dew formation phenomenon. 
     Description of the Related Art 
     In general, a refrigerator is a household appliance capable of keeping food fresh for a long time by having a storage compartment storing the food and a cold air supply device supplying cold air to the storage compartment. 
     A temperature inside the refrigerator is lower than a temperature outside the refrigerator, and dew may thus be formed inside the refrigerator in case that the door is opened. A heater has been conventionally installed on a door frame to prevent such a dew formation phenomenon. 
     However, the heater is operated at the same position with the same power irrespective of an environment inside and outside the refrigerator, and is thus unable to efficiently remove the dew from the refrigerator. 
     SUMMARY 
     Embodiments of the disclosure overcome the above disadvantages and other disadvantages not described above. In addition, the disclosure is not required to overcome the disadvantages described above, and an embodiment of the disclosure may not overcome any of the problems described above. 
     According to an embodiment of the disclosure, a refrigerator includes: a body having a storage compartment; a door pivotally coupled to the body to open and close the storage compartment; a planar heater including first heating wires arranged to surround an edge of the door and second heating wires arranged on only one portion of the edge; a sensor configured to measure at least one of temperature and humidity outside the refrigerator; and a processor configured to control driving of at least one of the first heating wires and the second heating wires based on a measured value of the sensor. 
     The second heating wires are arranged on a side edge of the door, most spaced apart from hinges respectively connecting the door and the body to each other. 
     The second heating wires are arranged extending to at least one of an upper side edge or a lower side edge, adjacent to the side edge. 
     The processor is configured to determine an operating duty of each of the first heating wires and the second heating wires based on at least one of a difference between temperatures inside and outside the refrigerator, and the humidity outside the refrigerator. 
     The processor is configured to determine an operating mode of the refrigerator based on at least one of the temperature and the humidity, measured by the sensor, and is configured to allow only the first heating wires to be driven in case that the determined operating mode is a normal mode and allow the first heating wires and the second heating wires to be driven together in case that the determined operating mode is a high temperature and high humidity mode. 
     The first heating wires and the second heating wires have heating performances different from each other. 
     The planar heater includes: a base film, a plurality of heating wires including the first and second heating wires and printed on one surface of the base film, a protective film laminated on the one surface of the base film to protect the plurality of heating wires; and a double-sided tape attached to the protective film. 
     The plurality of heating wires are printed with silver (Ag) nano ink. 
     The base film includes polyethylene terephthalate (PET) material. 
     The protective film includes ethylene-vinyl acetate copolymer (EVAC) material. 
     The door includes an inner door having an opening and an outer door pivoted in front of the inner door to open and close the opening, and the planar heater is installed on the inner door. 
     According to another embodiment of the disclosure, a control method of a refrigerator includes: measuring at least one of temperature and humidity outside the refrigerator; and driving at least one of first heating wires arranged to surround an edge of a door and second heating wires arranged on only one portion of the edge, based on a measured value. 
     The control method of a refrigerator further comprises determining an operating duty of each of the first heating wires and the second heating wires based on a difference between temperatures inside and outside the refrigerator, and the humidity outside the refrigerator, wherein in the driving of the heating wires, at least one of the first heating wires and the second heating wires are driven based on the operating duty of each of the first heating wires and the second heating wires. 
     The control method of a refrigerator further comprises determining an operating mode of the refrigerator based on the measured temperature and humidity, wherein in the driving of the heating wires, only the first heating wires are driven in case that the determined operating mode is a normal mode, and the first heating wires and the second heating wires are driven together in case that the determined operating mode is a high temperature and high humidity mode. 
     Additional and/or other aspects and advantages of the disclosure are set forth in part in the description which follows and, in part, are obvious from the description, or may be learned by practice of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and/or other aspects of the disclosure are more apparent by describing certain embodiments of the disclosure with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of a refrigerator according to an embodiment of the disclosure; 
         FIG. 2  is an enlarged perspective view of the refrigerator with a second door opened; 
         FIG. 3  is a perspective view of a third door from which a door guard is separated; 
         FIG. 4  is a front view of a planar heater in which a plurality of heating wires are arranged; 
         FIG. 5  is a cross-sectional view taken along line I-I of  FIG. 4 ; and 
         FIG. 6  is a flowchart showing a control method of a refrigerator according to another embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments described below are illustratively described to assist in understanding of the disclosure, and it is to be understood that the disclosure may be variously modified and executed unlike the embodiments described herein. However, if it is decided that a detailed description for the known functions or components related to the disclosure may obscure the gist of the disclosure, the detailed description and concrete illustration are omitted. Further, the accompanying drawings are not illustrated to scale, but sizes of some of components may be exaggerated to assist in the understanding of the disclosure. 
     Terms used in the specification and claims are selected as general terms in consideration of the functions in the disclosure. However, these terms may be changed depending on the intention of those skilled in the art, legal or technical interpretation, the emergence of a new technique and the like. In addition, some terms arbitrarily chosen by an applicant may exist. In this case, the meanings of such terms are mentioned in detail in corresponding description portions of the disclosure. Therefore, unless defined in detail, these terms may be interpreted on the basis of the contents throughout the disclosure and common technical knowledge in the art unless defined in detail. 
     In the disclosure, an expression ‘have’, ‘may have’, ‘include’, ‘may include’ or the like, indicates existence of a corresponding feature (for example, a numerical value, a function, an operation, a component such as a part or the like), and does not exclude existence of an additional feature. 
     In addition, the disclosure describes components necessary for the description of each embodiment of the disclosure, and is not necessarily limited thereto. Therefore, some components may be changed or omitted, and other components may be added. In addition, the components may also be distributed and arranged in independent devices different from each other. 
     Further, the embodiments of the disclosure are described in detail with reference to the accompanying drawings and contents described in the accompanying drawings, but the disclosure is not limited or restricted to the embodiments. 
     The disclosure provides a refrigerator having an improved heater structure to prevent a dew formation phenomenon. 
     Hereinafter, the disclosure is described in more detail with reference to the accompanying drawings. 
       FIG. 1  is a perspective view of a refrigerator  1  according to an embodiment of the disclosure.  FIG. 2  is an enlarged perspective view of the refrigerator with a second door  30  opened. 
     Referring to  FIGS. 1 and 2 , the refrigerator  1  may include: a body  10 ; doors  20 ,  30  and  40 ; drawers  50  and  60 ; and hinges  70 . 
     The refrigerator  1  may be a device for storing food or drugs at a predetermined temperature to chill or not to spoil the food or drugs. The refrigerator  1  is shown in a shape of a general household refrigerator, but is not limited thereto. The refrigerator  1  may be a kimchi refrigerator, alcohol refrigerator, cosmetic refrigerator, etc. 
     The body  10  may have a shape of an approximately rectangular parallelepiped with an open front surface, but is not limited thereto and may be formed in various sizes and shapes. 
       FIG. 1  shows that the refrigerator  1  has the doors  20  and  30  on both sides of its upper portion and the drawers  50  and  60  on its lower portion, but the refrigerator  1  is not limited thereto. Depending on a layout of the doors  20  and  30 , drawers  50  and  60  and storage compartments  11 ,  12  and  13 , the refrigerator  1  may be a French door type, a side-by-side type, etc. 
     The body  10  may have the storage compartments  11 ,  12  and  13  which are formed inside the body  10  and open by the opening and closing doors  20 ,  30  and  40  to store water, beverages and refrigerated or frozen food. 
     The body  10  may include an inner case (not shown) forming the storage compartments  11 ,  12  and  13 , an outer case (not shown) forming the outside of the refrigerator and an insulating material (not shown) maintaining a temperature difference between the inner case and the outer case. 
     The insulating material may prevent cold air inside the storage compartments  11 ,  12  and  13  from leaking to the outside, and prevent outside heat from entering the storage compartments  11 ,  12  and  13 . 
     The storage compartments  11 ,  12  and  13  may be divided from one another by partitions disposed inside the body  10 . The storage compartments  11 ,  12  and  13  may be divided into freezer compartments  12  and  13  respectively disposed at the lower portion of the refrigerator  1  and a refrigerator compartment  11  disposed at its upper portion. However, the freezer compartments  12  and  13  and the refrigerator compartment  11  are not limited to this arrangement, and may be arranged in reverse positions. 
     The first door  20  may open and close a portion of a front surface of the storage compartment  11  by being pivoted at an angle (e.g. 300° or less) determined by hinges  70   a  and  70   b.    
     The first door  20  may display functions and settings of the refrigerator  1  on its surface, and may include an operation panel  21  changeable by a user&#39;s input (e.g., touch or button selection), a dispenser  22  for providing water, ice or carbonated water, and/or a graspable handle  25 . 
     The second door (or outer door)  30  and/or the third door (or inner door)  40  may be respectively pivoted at an angle (e.g., 300° or less) determined by hinges  70   c  to  70   f , to open and close the other portion of the front surface of the storage compartment  11 . 
     The second door  30  may include a graspable handle  35 . The handle  25  of the first door  20  and the handle  35  of the second door  30  may be positioned to be spaced apart from each other with respect to a central area of the storage compartment  11 . 
     The second door  30  and the third door  40  opening and closing the other portion of the first storage compartment  11  may be installed as double doors. However, the disclosure is not limited thereto, and the first door  20  and its adjacent door may be installed as double doors. 
     The second door  30  may be relatively pivotally coupled to the third door  40 . That is, the second door  30  may be opened or closed independently from the third door  40 , and may be opened or closed together with the third door  40 . 
     The third door  40  may include an opening corresponding to the other portion of the first storage compartment  11 . The opening of the third door  40  may be opened or closed by the second door  30 . 
     In case that the second door  30  is opened by the user, a door guard  80  installed in the opening of the third door  40  may be exposed to the outside. The door guard  80  may include a plurality of shelves capable of storing the food, and may be detachably coupled to the third door  40 . 
     The user may open only the second door  30 , and may easily access the food and the like, stored in the door guard  80 . In addition, the leakage of the cold air to the outside of the refrigerator  1  in case that only the second door  30  is opened may be reduced than in case that the second door  30  and the third door  40  are opened together. 
     As described above, the second door  30  and the third door  40  may be disposed double, and each door may be configured to be able to be pivoted relatively to each other. Accordingly, the food may be put in and out in various ways based on the user&#39;s need, and the leakage of the cold air may be minimized. 
     Meanwhile, in case that the second door  30  and the third door  40  are closed, the third door  40  may maintain a low temperature by the cold air supplied to the inside of the first storage compartment  11 . In case that the user opens the second door  30 , dew may be formed on a front surface of the third door  40  due to a temperature difference between the third door  40  and the outside air. 
     As described below, this dew formation phenomenon may be resolved by installing a planar heater  100  (see  FIG. 4 ) along an edge of the third door  40 . 
       FIG. 3  is a perspective view of the third door  40  from which the door guard  80  is separated. Referring to  FIG. 3 , the third door  40  may include a door frame  41  having the opening, an upper frame  42  and a lower frame  43  respectively disposed on upper and lower sides of the third door  40  and a guard support  44  coupled to a rear side of the door frame  41 . 
     A foam space (not shown) may be formed between the door frame  41  and the guard support  44 , and an insulating material may be foamed in the foam space. 
     The planar heater  100  may be installed on a back surface of the door frame  41  to remove the dew formation. The planar heater  100  may receive power by being connected to a power supply (or coil driving device) positioned inside the body  10 . 
     The planar heater  100  may be installed to generate heat by receiving the power. In case that the first planar heater  100  is heated up, a temperature of the door frame  41  may be increased. Accordingly, the temperature difference between the door frame  41  and the outside air may be decreased, thereby preventing the dew formation. 
     The planar heater  100  may have the form of a film and may be attached to the back surface of the door frame  41 . One surface of the planar heater  100  may have an adhesive surface having adhesive strength. Without any separate fastening mechanism, the planar heater  100  may be attached to the back surface of the door frame  41  using the adhesive strength of the adhesive surface. 
     The planar heater  100  may be attached along an outer edge of the door frame  41 . The planar heater  100  may be disposed adjacent to a gasket (not shown) of the second door  30 , which is installed in front of the door frame  41 . In detail, the planar heater  100  may be disposed adjacent to an outer rim of the gasket. The planar heater  100  may be disposed in this manner because the dew may generally be formed on an outer rim of the door frame  41 , adjacent to the gasket of the outer door. 
       FIG. 4  is a front view of the planar heater  100  in which a plurality of heating wires  120  (shown as  120   a  and  120   b  in  FIG. 4 ) are arranged. Referring to  FIG. 4 , the planar heater  100  may have an opening  101  corresponding to the opening of the third door  40 , and may have an overall shape corresponding to that of the third door  40 . 
     The planar heater  100  may have the form of the film. The planar heater  100  may include a base film  110  (see  FIG. 5 ), heating wires  120  (shown as  120   a  and  120   b  in  FIGS. 4 and 5 ) printed on the base film and a terminal  150  (shown as  150   a  and  150   b  in  FIG. 4 ) for supplying the power to the heating wires  120  from an external power source (not shown). 
     The heating wires  120  may be printed on the base film, and may thus maintain a predetermined interval therebetween and be arranged in a specific shape in a fixed position. Therefore, it is possible to prevent a short-circuit between the heating wires  120 , and easily manufacture the planar heater  100 . 
     The planar heater  100  may have a separate opening  170  formed in a portion where a latch of the third door  40  is disposed. Through this opening, the planar heater  100  may be attached to the door frame  41  without interference of the latch. 
     The planar heater  100  may include a plurality of heating wires  120 . In detail, the planar heater  100  may include first heating wires  120   a  arranged to surround an edge of the planar heater  100  and second heating wires  120   b  arranged on only one portion of the edge of the planar heater  100 . 
     However, the number of the heating wires  120  is exemplary and is not limited thereto. Additional heating wires  120  may be arranged based on temperature and humidity outside the refrigerator  1 , a degree of the dew formation, etc. 
     It is possible to have the same effect as having a plurality of planar heaters by arranging the plurality of heating wires  120  on one film. In detail, the plurality of heating wires  120  may be printed on the one film, and high heating effect may thus be expected with neither a complicated inner structure of the third door  40  nor an increased thickness of the third door  40 . 
     The second heating wires  120   b  may be arranged on a side edge of the door, most spaced apart from the hinges  70   e  and  70   f  respectively connecting the third door  40  and the body  10  to each other. The side edge may be a portion where a difference between the temperatures inside and outside the third door  40  is the largest as the second door  30  is opened. 
     That is, the second heating wires  120   b  arranged on the side edge may be driven to intensively generate the heat in a region where the dew may be easily formed, thereby effectively preventing the dew formation phenomenon. 
     In particular, the second heating wires may be arranged not on the entire edge of the door but on only a portion thereof. Accordingly, the second heating wires may have lower power consumption than the first heating wires, and may be operated in conjunction with or independently from the first heating wires as described below, thereby more efficiently preventing the dew formation phenomenon. 
     However, the second heating wires  120   b  are not limited to this arrangement, and may be arranged extending to at least one of an upper side edge or a lower side edge, adjacent to the side edge. In addition, it is also possible to experimentally find a position where the most dew is formed on the third door  40  and arrange the second heating wires  120   b  intensively on that position. 
     In addition, as shown in the drawing, the heating wires  120  may be formed in a zigzag shape in which some sections thereof have winding curves. The heating wires  120  may tend to have its length and heat generation amount proportional to each other. Therefore, it is possible to effectively prevent the dew formation phenomenon in case that the heating wires  120  have the zigzag shape to have a long length in a region where the dew may be easily formed due to the large difference between the temperatures inside and outside the refrigerator  1 . 
     In addition, the first heating wires  120   a  and the second heating wires  120   b  may have heating performances different from each other. For example, the first heating wires  120   a  may have a heating performance of 8 watt (W) and the second heating wires  120   b  may have that of 6 watt (W), but such heating performances are exemplary and may be set in various ways based on a surrounding environment, a target temperature of the refrigerator  1 , etc. 
     That is, the plurality of heating wires  120  may have the heating performances different from each other, and may thus perform heat-generating operation in various cases based on the environment outside the refrigerator  1 , thereby effectively preventing the dew formation phenomenon. 
     The refrigerator  1  may include: a sensor (not shown) configured to measure at least one of temperature and humidity outside the refrigerator  1 ; and a processor (not shown) configured to control driving of at least one of the first heating wires  120   a  and the second heating wires  120   b  based on a measured value of the sensor. 
     In detail, the processor may be configured to determine an operating duty of each of the first heating wires  120   a  and the second heating wires  120   b  based on at least one of a difference between temperatures inside and outside the refrigerator  1 , and the humidity outside the refrigerator  1 , measured by the sensor. 
     The operating duty of each of the heating wires  120  may refer to a time ratio in which the heating wires  120  are driven per unit time. In detail, the heating wires  120  may not be simply driven in both ON/OFF states, but the driving time ratio may be variously determined based on a condition outside the refrigerator  1 . 
     In detail, in case of determining the operating duty of each of the heating wires based on the measured value received from the sensor, the processor may allow a pulse width modulation (PWM) signal corresponding to the determined operating duty to be output. Accordingly, a current corresponding to the operating duty may flow from the external power source to each of the heating wires  120 . 
     For example, in case that the environment outside the refrigerator  1  has high temperature and high humidity and the dew may thus be easily formed on the third door  40 , the sensor may transmit information on the temperature and/or humidity outside the refrigerator to the processor, and the processor may determine a high operating duty of each of the heating wires  120  (for example, 80% and 95% may be the respective operating duties of the first heating wires and the second heating wires). 
     Meanwhile, in case that the environment outside the refrigerator  1  has low temperature and low humidity and the dew may thus be hardly formed on the third door  40 , the sensor may transmit the information on the temperature and/or humidity outside the refrigerator to the processor, and the processor may determine a low operating duty of each of the heating wires  120  (for example, 5% and 15% may be the respective operating duties of the first heating wires and the second heating wires). 
     That is, the processor may flexibly determine the operating duties of the plurality of heating wires  120  based on the environment outside the refrigerator  1 , thereby improving its energy efficiency. In addition, the processor may individually control the plurality of heating wires  120  arranged on positions different from each other to intensively heat a region vulnerable to the dew formation phenomenon (for example, a region where the second heating wires  120   b  are disposed), thereby efficiently preventing the dew formation phenomenon. 
     In addition, the processor may be configured to determine an operating mode of the refrigerator based on at least one of the temperature and the humidity, measured by the sensor, and may be configured to allow only the first heating wires  120   a  to be driven in case that the determined operating mode is a normal mode and allow the first heating wires  120   a  and the second heating wires  120   b  to be driven together in case that the determined operating mode is a high temperature and high humidity mode. 
     That is, in case that the temperature or humidity outside the refrigerator  1  is lower than a predetermined value, the processor may determine the operating mode as the normal mode and allow only the first heating wires  120   a  to be driven. 
     Meanwhile, in case that the temperature or humidity outside the refrigerator  1  is higher than the predetermined value, the processor may determine the operating mode as the high temperature and high humidity mode and allow the first heating wires  120   a  and the second heating wires  120   b  to be driven together. 
     Through the above-described control manner of the processor, it is possible to prevent unnecessary power waste of the planar heater  100 , and achieve flexible and efficient power consumption in response to the environment outside the refrigerator  1 . 
       FIG. 5  is a cross-sectional view taken along line I-I of  FIG. 4 . Referring to  FIG. 5 , the planar heater  100  may include: the base film  110 ; heating wires  120  printed on one surface of the base film  110  by gravure printing; a protective film  130  laminated on the one surface of the base film  110  to protect the heating wires  120 ; and a double-sided tape  140  attached to the protective film  130 . 
     The base film  110  may be disposed on one surface of the planar heater  100 , and the double-sided tape  140  may be disposed on the other surface of the planar heater  100 . The other surface of the planar heater  100  on which the double-sided tape  140  is disposed may have the adhesive strength due to the double-sided tape  140 , and may thus be easily adhered and fixed to the door frame  41 . 
     The base film  110  may include polyethylene terephthalate (PET) material. 
     The heating wires  120  may receive the current and generate the heat. The heating wires  120  may be printed with silver (Ag) nano ink. 
     The protective film  130  may include polyethyleneterephthalate (PET) and ethylene-vinyl acetate copolymer (EVA) materials. 
     One surface of the double-sided tape  140  may be attached to the protective film  130 . Although not shown in the drawing, the double-sided tape  140  may be attached to the base film  110 . The planar heater  100  may have the double-sided tape  140  disposed on its one surface, and may thus be attached to a to-be-attached object by contacting the one surface on which the double-sided tape  140  is disposed to the to-be-attached object. 
       FIG. 6  is a flowchart showing a control method of a refrigerator according to another embodiment of the disclosure. Referring to  FIG. 6 , a control method of a refrigerator  1  may include: measuring at least one of temperature and humidity outside the refrigerator  1  (S 610 ); and driving at least one of first heating wires  120   a  arranged to surround an edge of a door and second heating wires  120   b  arranged on only one portion of the edge, based on a measured value (S 620 ). 
     That is, a sensor may measure at least one of the temperature and humidity outside the refrigerator  1 , and the processor may determine whether to allow all or only one of the first heating wires  120   a  and the second heating wires  120   b  arranged at positions different from each other to be driven, depending on whether the measured value received from the sensor meets a predetermined condition. 
     In addition, the control method of the refrigerator  1  may further include determining an operating mode of the refrigerator based on the measured temperature and humidity, wherein in the driving of the heating wires (S 620 ), only the first heating wires  120   a  may be driven in case that the determined operating mode is a normal mode, and the first heating wires  120   a  and the second heating wires  120   b  may be driven together in case that the determined operating mode is a high temperature and high humidity mode. 
     For example, in case that the environment outside the refrigerator  1  has high temperature and high humidity, the sensor may transmit information on the temperature and/or humidity outside the refrigerator to the processor, and the processor may determine the operating mode of the plurality of heating wires  120  as the high temperature and high humidity mode and allow the first heating wires  120   a  and the second heating wires  120   b  to be driven together. 
     Meanwhile, in case that the environment outside the refrigerator  1  has low temperature and low humidity, the sensor may transmit the information on the temperature and/or humidity outside the refrigerator to the processor, and the processor may determine the operating mode of the plurality of heating wires  120  as the normal mode and allow only the first heating wires  120   a  to be driven. 
     In addition, the control method of the refrigerator  1  may further include determining an operating duty of each of the first heating wires  120   a  and the second heating wires  120   b  based on a difference between temperatures inside and outside the refrigerator  1 , and the humidity outside the refrigerator  1 , wherein in the driving of the heating wires (S 620 ), at least one of the first heating wires  120   a  and the second heating wires  120   b  may be driven based on the operating duty of each of the first heating wires  120   a  and the second heating wires  120   b.    
     That is, the processor may not simply determine on/off state of the plurality of heating wires  120 , but may determine the operating duty of each of the heating wires  120  and allow the plurality of heating wires  120  to be driven based on the determined operating duty. 
     Accordingly, each of the plurality of heating wires  120  may be variously driven with the operating duty having the best power efficiency based on the environment outside the refrigerator  1 , thereby more actively preventing the dew formation phenomenon. 
     Although the embodiments of the disclosure are illustrated and described hereinabove, the disclosure is not limited to the above-mentioned specific embodiments, but may be variously modified by those skilled in the art to which the disclosure pertains without departing from the scope and spirit of the disclosure as disclosed in the accompanying claims. These modifications also need to be understood to fall within the scope of the disclosure.