Internal temperature change suppression-type ready-made food vending machine

Abstract

An internal temperature change suppression-type ready-made food vending machine of the present invention comprises: a housing unit of which one surface is open and which has a first inner space and a second inner space formed therein, the first inner space having formed therein a storage area in which a plurality of ready-made foods are stored in multi-tier form in the direction of the open one surface, and a discharge area which is extendedly formed below the storage area and into which the stored ready-made foods are dropped, and the second inner space neighboring the first inner space, corresponding in shape to the first inner space, and storing therein ready-made foods requiring storage in a lower temperature state than the ready-made foods stored in the storage area of the first inner space; a cold energy provision unit comprising a first cold energy provision portion and a second cold energy provision portion; a pair of opening / closing units; a pair of sensor units for individually measuring the respective temperatures of the storage areas of the first and second inner spaces; and a control unit for controlling the cold energy provision unit on the basis of the respective temperatures of the storage areas identified from the sensor units so as to maintain the respective temperatures of the storage areas within respective temperature ranges which are preset for the storage areas.

Description

Convenience food vending machine that suppresses internal temperature changes

[0001] The present invention relates to a ready-to-cook food sales device that suppresses internal temperature changes.

[0002]

[0003] In response to the modern need to easily consume the food they desire, the demand for convenient ready-to-eat foods, which are easy to store and can be conveniently prepared using heating methods such as microwave ovens, is rapidly increasing.

[0004] These ready-to-eat foods were generally sold by being placed in refrigerators or freezers at supermarkets or convenience stores, but recently, they are also being sold in unmanned stores, which can reduce labor costs compared to existing manned stores.

[0005] Meanwhile, since a store in the form of a physical store must be operated even in the case of an unmanned store, selling ready-to-eat food using an automatic vending machine that does not require a store form is a method to minimize operating costs. As part of this method, Korean Registered Patent Publication No. 10-2607226 (Application Date: Nov. 09, 2021; Publication Date: Nov. 29, 2023; hereinafter referred to as "prior art") disclosed a vending machine technology for selling refrigerated products, which is provided in the form of a modular refrigerator in which refrigerated products are individually stored inside, and allows the refrigerated products stored inside to be withdrawn by opening the door of each module unit.

[0006] However, conventional technology had a problem in that whenever a stored refrigerated product was purchased, the storage area of ​​the purchased refrigerated product was opened, which could lead to internal heat loss, and furthermore, the continuously lost heat could cause the convenience food stored inside to spoil.

[0007]

[0008] The present invention aims to provide an internal temperature change suppression type convenience food dispensing device that minimizes temperature changes occurring in the storage area during the process of withdrawing convenience food from the storage area, in order to solve the aforementioned problems.

[0009]

[0010] A sales device for convenient ready-to-cook food that suppresses internal temperature change according to an embodiment of the present invention comprises: a housing part having one side open, a storage area in which a plurality of convenient ready-to-cook foods are stored in a multi-stage form in the direction of the open side, and a discharge area formed extending downward from the storage area where the stored convenient ready-to-cook foods fall; a second internal space formed adjacent to the first internal space and corresponding to the shape of the first internal space, wherein the second internal space is for storing convenient ready-to-cook foods that require storage at a lower temperature than the convenient ready-to-cook foods stored in the storage area of ​​the first internal space; a pair of door parts that individually open and close the open side of the housing part in which the storage area and discharge area of ​​the first and second internal spaces are formed, and each door part having a discharge portion formed individually in communication with the discharge area of ​​the first and second internal spaces for discharging convenient ready-to-cook foods on the discharge area; and a cooling part disposed inside the housing part and including a first cooling part that provides cooling to the storage area of ​​the first and second internal spaces and a second cooling part that provides cooling to the storage area of ​​the second internal space. The device is characterized by comprising: an opening / closing unit positioned between the storage area and the discharge area of ​​the first and second internal spaces of the housing unit, which opens toward the discharge area by the load of a ready-to-cook food falling from the storage area toward the discharge area and returns toward the storage area by elastic restoring force to close the storage area; a pair of sensor units that individually measure the temperature of the storage area of ​​the first and second internal spaces; and a control unit that controls the cooling / heat supply unit according to the temperature of each storage area confirmed by the sensor units, thereby maintaining the temperature of each storage area within a preset temperature range for each storage area.

[0011] In addition, it is characterized by further including a sensing unit positioned on the discharge area of ​​the first and second internal spaces, respectively, for detecting whether a convenient ready-to-cook food is located in the discharge area.

[0012] At this time, the sensing unit is provided with a plurality of load-cell sensors disposed on the bottom surface of the discharge areas of the first and second internal spaces, and is characterized by detecting a load change of a certain level or higher applied to the bottom surface of each discharge area to detect whether a ready-to-cook food is located in each discharge area.

[0013] In addition, the control unit is characterized by controlling the cold heat supply unit to provide cold heat to a storage area corresponding to the discharge area for a preset time when the discharge of a ready-to-cook food is confirmed through the detection unit to be from a specific discharge area.

[0014] Herein, the control unit comprises: a control portion that controls a cold / heat supply unit according to the detection result of the sensing unit; and an identification portion that identifies a ready-to-cook food according to the weight of the ready-to-cook food measured by the sensing unit, wherein information regarding the weight of all ready-to-cook foods stored in each storage area of ​​the first and second internal spaces is stored, and the identification portion is characterized by storing cooking information in the form of a data table in which the weight of each ready-to-cook food and the cooking method of each ready-to-cook food are matched and stored.

[0015] Additionally, it is characterized by further including a display unit disposed on the outer surface of the door unit and outputting a cooking method of a ready-to-cook food identified from the identification unit.

[0016] In addition, it is characterized by further including a monitoring unit that detects the rotation of the opening / closing unit and monitors the opening / closing status of each storage area of ​​the opening / closing unit.

[0017] In addition, the control unit is characterized by controlling the cold heat supply unit to provide cold heat to the storage area corresponding to the discharge area for a preset time, only when a load change of a certain level or more is detected by at least one of the pair of sensing units, and it is confirmed through the monitoring unit that all opening and closing units are closing their respective storage areas.

[0018]

[0019] The convenience food sales device with internal temperature change suppression type according to the present invention has the effect of minimizing temperature changes of convenience food stored in the storage area by the sold convenience food by checking whether the convenience food is discharged from the storage area and whether the storage area is opened or closed through the opening / closing part, and by providing cold heat for a preset time to the storage area from which the convenience food has been discharged, thereby maintaining the temperature of each storage area at a preset temperature.

[0020] In addition, the convenience food sales device with internal temperature change suppression type according to the present invention identifies the type of convenience food according to the weight of the discharged convenience food, outputs a cooking method corresponding to the identified convenience food through a display unit and provides it to the buyer, and by providing the buyer with a cooking method that corrects the cooking time according to the difference between the suitable storage temperature of the convenience food and the current storage temperature, it has the effect of helping the buyer cook the convenience food purchased to an optimal eating state.

[0021]

[0022] FIG. 1 illustrates a convenient ready-to-cook food sales device that suppresses internal temperature change according to a preferred embodiment of the present invention.

[0023] FIG. 2 visualizes an example of temperature control of the first and second storage areas through the sensor unit of a convenient ready-to-eat food sales device that suppresses internal temperature changes according to a preferred embodiment of the present invention.

[0024] FIG. 3 visualizes an example of temperature control by a sensing unit and a monitoring unit in the first discharge area of ​​a convenient ready-to-cook food sales device that suppresses internal temperature changes according to a preferred embodiment of the present invention.

[0025]

[0026] Hereinafter, a preferred embodiment of the convenient ready-to-cook food sales device of the present invention, which suppresses internal temperature changes, will be described in detail with reference to the attached drawings.

[0027] Identical reference numerals in each drawing indicate identical components. Furthermore, specific structural or functional descriptions regarding embodiments of the present invention are illustrative merely for the purpose of explaining embodiments according to the present invention. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and unless explicitly defined in this specification, it is preferable not to interpret them in an ideal or overly formal sense.

[0028] Before describing the convenience food vending device with internal temperature change suppression type according to a preferred embodiment of the present invention with reference to the drawings, the convenience food vending device with internal temperature change suppression type according to the present invention may be provided in the form of an automatic vending device combined with a refrigerator and a freezer, in which convenience food in a refrigerated or frozen state is stored separately inside, and when a buyer selects the convenience food they wish to purchase and payment for the said convenience food is completed, the payment for the convenience food is discharged to a discharge area. For the sake of brevity, the description of the configurations for purchasing, payment, and payment, etc., is abbreviated below, and only the configuration for suppressing internal temperature change is described; however, it should be understood that the operation configuration for purchasing, the configuration for payment, and the configuration for dropping and discharging the payment for the convenience food from the storage area to the discharge area are also included in the convenience food vending device with internal temperature change suppression type according to the present invention.

[0029]

[0030] FIG. 1 illustrates a convenient ready-to-cook food sales device that suppresses internal temperature change according to a preferred embodiment of the present invention.

[0031] Referring to FIG. 1, the internal temperature change suppression type convenience food sales device (100) according to a preferred embodiment of the present invention separately stores and discharges a refrigerated convenience food (R, hereinafter referred to as the 'first convenience food') and a frozen convenience food (F, hereinafter referred to as the 'second convenience food'), and can measure the temperature of the area where the first convenience food (R1) is stored and the area where the second convenience food (R2) is stored and maintain them at a preset temperature, and may include a housing part (110), a door part (120), a cooling / heating part (130), an opening / closing part (140), a sensor part (150), a detection part (160), a display part (170), a monitoring part (180), and a control part (190).

[0032] A housing part (110) has one side open, and a first storage area (s1) in which a plurality of first convenient cooking foods (R1) are stored in a multi-stage form in the direction of the open side, and a discharge area (e1) in which the first convenient cooking foods (R1) stored below the storage area (s1) fall are formed, and a second storage area (s2) and a second discharge area (e2) are formed adjacent to the first internal space (I2) and corresponding to the shape of the first internal space (I1), and a second internal space (I2) in which a second convenient cooking food (R2) that requires storage at a lower temperature than the first convenient cooking food (R1) stored in the first storage area (s1) is stored in the second storage area (s2) can be formed.

[0033] A door section (120) is provided as a pair that individually opens and closes the open side of the housing section (110) in which the first and second internal spaces (I1, I2) are formed, and a discharge section (122) can be individually formed in each, which communicates with the first or second discharge area (e1, e2) and discharges a ready-to-cook food (R, F) located on the first or second discharge area (e1, e2).

[0034] Here, the housing part (110) and the door part (120) may have a shape formed by connecting two ordinary vending machines next to each other, as shown in FIG. 1.

[0035] The cold heat providing unit (130) is disposed inside the housing unit (110) and may include a first cold heat providing unit (132) that provides cold heat to the first and second storage areas (s1, s2) and a second cold heat providing unit (134) that provides cold heat to the second storage area (s2). Here, since the second storage area (s2) stores a second ready-to-cook food (R2) that requires storage at a lower temperature than the first ready-to-cook food (R1), the second cold heat providing unit (134) individually provides cold heat to the second storage area (s2) so that a lower temperature than that of the first storage area (s1) is maintained.

[0036] The opening / closing part (140) includes a first opening / closing part (142) located between the first storage area (s1) and the first discharge area (e1) of the housing part (110), and a second opening / closing part (144) located between the second storage area (s2) and the second discharge area (e2). It can be opened in the direction of the discharge area (e1, e2) by the load of a ready-to-cook food (R, F) falling from each storage area (s1, s2) toward the discharge area (e1, e2), and can be closed by returning toward the storage area (s1, s2) by elastic restoring force. Here, the first and second opening / closing parts (142, 144) may be provided in the form of a swing door combined with an elastic spring, and may be provided in a form in which a material with low thermal conductivity or a material with low thermal conductivity is attached to the surface facing the storage area (s1, s2). At this time, the first and second opening / closing parts (142, 144) are each provided to prevent low-temperature air in the first or second storage area (s1, s2) from flowing out into the first or second discharge area (e1, e2).

[0037] If a purchaser makes a payment for the first or second ready-to-eat food (R, F) and the ready-to-eat food (R, F) stored in the storage area (s1, s2) falls toward the first or second discharge area (e1, e2), the ready-to-eat food (R, F) falls and lands on the upper part of the first or second opening / closing part (142, 144) and descends together with the ready-to-eat food (R, F), thereby positioning the ready-to-eat food (R, F) in the first or second discharge area (e1, e2) and maintaining the first or second storage area (s1, s2) in a closed state again, the leakage of low-temperature air within the first or second storage area (s1, s2) into the first or second discharge area (e1, e2) is minimized.

[0038]

[0039] FIG. 2 visualizes an example of temperature control of the first and second storage areas through the sensor unit of the internal temperature change suppression type convenience food sales device according to a preferred embodiment of the present invention, and FIG. 3 visualizes an example of temperature control of the control part through the detection unit and monitoring unit in the first discharge area of ​​the internal temperature change suppression type convenience food sales device according to a preferred embodiment of the present invention.

[0040] Referring to FIGS. 1 and 2, the sensor unit (150) may include a first sensor part (152) disposed on a first storage area (s1) to measure the temperature of the first storage area (s1) and a second sensor part (154) disposed on a second storage area (s2) to measure the temperature of the second storage area (s2). Here, the measured values ​​of the first sensor part (152) and the second sensor part (154) may be used as reference values ​​for controlling the cooling unit (130) by the control part (192) of the control unit (190) to be described later, in order to check the temperature of the first storage area (s1) or the second storage area (s2) and to maintain the temperature of the first storage area (s1) or the second storage area (s2) within a preset temperature range. At this time, it is preferable that the first and second sensor parts (152) be placed in the upper center of the first and second storage areas (s1, s2), where the temperature is relatively high due to convection.

[0041] The detection unit (160) includes a first detection part (162) located on the first discharge area (e1) and a second detection part (164) located on the second discharge area (e2), so as to detect whether a ready-to-cook food (R, F) is located in each discharge area (e1, e2). Here, the first and second detection parts (162, 164) are each provided with a plurality of load-cell sensors placed on the bottom surface of the first or second discharge area (e1, e2), and detect a change in load corresponding to the weight of the ready-to-cook food (R, F) on the bottom surface of each discharge area (e1, e2), thereby detecting whether the ready-to-cook food (R, F) is located in each discharge area (e1, e2).

[0042] The display unit (170) can be provided in the form of a conventional monitor that outputs an image and is placed on the outer surface of the door unit (120).

[0043] The monitoring unit (180) may include a first monitoring unit (182) that monitors the rotation of the first opening / closing unit (142) and a second monitoring unit (184) that monitors the rotation of the second opening / closing unit (144), and may monitor the opening / closing status of each storage area (s1, s2) by the first or second opening / closing unit (182, 184). At this time, the first and second monitoring units (184) may be provided in the form of a Hall effect sensor, and the first and second opening / closing units (142, 144) may also be provided in a form in which a conductor that responds to magnetism is combined with a region that rotates due to the load of the ready-to-cook food (R, F).

[0044] The control unit (190) controls the cooling unit (130) according to the temperature of each storage area (s1, s2) confirmed by the sensor unit (150) so that the temperature of each storage area (s1, s2) can be maintained within a preset temperature range for each storage area (s1, s2), and may include a control unit (192) and an identification unit (194).

[0045] The control unit (192) controls the cooling unit (130) according to the temperature of each storage area (s1, s2) confirmed by the first and second sensor units (152, 154), so that the temperature of each storage area (s1, s2) can be maintained within a preset temperature range for each storage area (s1, s2). At this time, when the control unit (192) detects from the first or second detection unit (162, 164) that a ready-to-cook food (R, F) is located in the first or second discharge area (e1, e2), it checks from both the first and second monitoring units (182, 184) whether the first and second opening / closing units (142, 144) are in a state of closing the first and second storage areas (s1, s2), and only when it is confirmed that the first and second opening / closing units (142, 144) are closing the first and second storage areas (s1, s2), it controls the cold / heat providing unit (130) to provide cold / heat to the first or second storage area (s1, s2) corresponding to the first or second discharge area (e1, e2) for a preset time.

[0046] The identification portion (194) stores information regarding the weight of all convenient ready-to-cook foods (R, F) stored in the first and second storage areas (s1, s2), and can identify the type of convenient ready-to-cook food (R, F) based on the weight of the convenient ready-to-cook food (R, F) measured by the first or second sensing portion (162, 164). At this time, the identification portion (194) may store cooking information in the form of a data table in which the weight of each convenient ready-to-cook food (R, F) and the cooking method of each convenient ready-to-cook food (R, F) are matched and stored, and when the weight corresponding to a specific convenient ready-to-cook food (R, F) is detected through the first or second sensing portion (162, 164), the cooking method of the corresponding convenient ready-to-cook food (R, F) can be output through the display portion (170). At this time, the identification part (194) prepares a cooking method for a specific ready-to-cook food (R, F) when the weight corresponding to the ready-to-cook food (R, F) is detected through the first or second detection part (162, 164), and then outputs the cooking method through the display part (170) when the ready-to-cook food (R, F) is discharged from the discharge area (e1, e2) and the weight is not detected by the first or second detection part (162, 164), thereby providing information about the cooking method of the ready-to-cook food (R, F) to the buyer who purchased the ready-to-cook food (R, F).

[0047] In addition, the cooking information stored in the identification part (194) may include information regarding the appropriate storage temperature of the corresponding ready-to-cook food (R, F), and the identification part (194) may check the storage temperature, which is the temperature of the storage area (s1, s2) where the corresponding ready-to-cook food (R, F) was stored, from the first or second sensor part (152, 154) placed on the same internal space (I1, I2) as the detection part (162, 164) at the time when the weight corresponding to the specific ready-to-cook food (R, F) is detected through the first or second detection part (162, 164), and depending on the difference between the appropriate storage temperature and the storage temperature in the cooking information, partially correct the information regarding the cooking time in the cooking method of the corresponding ready-to-cook food (R, F) and output it through the display part (170).

[0048] Additionally, if the control unit (192) confirms through the monitoring unit (180) that the opening / closing unit (140) remains in an open state after the discharge of the ready-to-cook food (R, F), it checks whether the open state of the opening / closing unit (140) is due to contact interference with the ready-to-cook food (R, F) discharged into the discharge area (E1, E2), and displays a notification message on the display unit (170) to encourage the buyer to obtain the ready-to-cook food (R, F) on the discharge area (E1, E2) through the discharge unit (122). At this time, when the control unit (192) confirms through the detection unit (160) that the identification unit (194) does not have information corresponding to the weight of the ready-to-cook food (R, F) located in the specific discharge area (E1, E2) within the stored cooking information, it checks through the monitoring unit (180) whether the first or second opening / closing unit (142, 144) at the location corresponding to the discharge area (E1, E2) is in a closed state. If it is confirmed that the first or second opening / closing part (142, 144) at a position corresponding to the discharge area (E1, E2) is in an open state, it is determined that the first or second opening / closing part (142, 144) being kept in an open state is due to contact interference with the ready-to-cook food (R, F) discharged into the discharge area (E1, E2), and a notification message is output to the display unit (170) to request the buyer to adjust the position of the ready-to-cook food (R, F) located in the discharge area (E1, E2).Afterward, after the buyer adjusts the position of the ready-to-cook food (R, F), if information corresponding to the weight corresponding to the ready-to-cook food (R, F) is confirmed within the cooking information stored from the identification part (194) through the detection part (160), the identification part (194) outputs the cooking method corresponding to the ready-to-cook food (R, F) to the display part (170), and the control part (192) checks again through the monitoring part (180) whether all opening / closing parts (142, 144) are in a closed state, and if it is confirmed that all opening / closing parts (142, 144) are in a closed state, the storage area (S1, S2) corresponding to the discharge area (E1, E2) from which the ready-to-cook food (R, F) was discharged is checked through the identification part (194), and the first cold heat providing part (132) or the first and second cold heat providing parts (132, 134) is controlled so that cold heat is provided to the storage area (S1, S2) for a preset time, thereby suppressing the temperature change of the ready-to-eat food (R, F) stored in the storage area (S1, S2) due to the discharge of the ready-to-eat food (R, F).

[0049]

[0050] That is, the convenience food sales device with internal temperature change suppression type according to the present invention has the effect of minimizing temperature changes of convenience food stored in the storage area by the sold convenience food by confirming whether the convenience food is discharged from the storage area and whether the storage area is opened or closed through the opening / closing part, and by providing cold heat for a preset time to the storage area from which the convenience food has been discharged, thereby maintaining the temperature of each storage area at a preset temperature.

[0051] In addition, the convenience food sales device with internal temperature change suppression type according to the present invention identifies the type of convenience food according to the weight of the discharged convenience food, outputs a cooking method corresponding to the identified convenience food through a display unit and provides it to the buyer, and by providing the buyer with a cooking method that corrects the cooking time according to the difference between the suitable storage temperature of the convenience food and the current storage temperature, it has the effect of helping the buyer cook the convenience food purchased to an optimal eating state.

[0052]

[0053] The embodiments of the present invention described above are disclosed for illustrative purposes only, and those skilled in the art with ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes, and additions should be considered to fall within the scope of the following claims.

Claims

1. A housing part having one side open, a storage area in which a plurality of convenient ready-to-cook foods are stored in a multi-tiered form in the direction of the open side, and a discharge area formed extending downward from the storage area for which the stored convenient ready-to-cook foods fall, and a second internal space formed adjacent to the first internal space and corresponding to the shape of the first internal space, wherein the second internal space is formed for storing convenient ready-to-cook foods that require storage at a lower temperature than the convenient ready-to-cook foods stored in the storage area of ​​the first internal space; A pair of door sections that individually open and close an open side of the housing section in which the first and second internal spaces are formed, and each door section that communicates with the discharge area of ​​the first and second internal spaces and has a discharge portion formed therein for discharging a ready-to-cook food on the discharge area; A cooling portion disposed inside the above housing portion and comprising a first cooling portion that provides cooling to storage areas of the first and second internal spaces, and a second cooling portion that provides cooling to storage areas of the second internal space; An opening / closing part positioned between the storage area and the discharge area of ​​the first and second internal spaces of the housing part, respectively, which opens toward the discharge area by the load of a ready-to-cook food falling from the storage area toward the discharge area, and returns toward the storage area by elastic restoring force to close the storage area; A pair of sensor units for individually measuring the temperature of the storage areas of the first and second internal spaces; and A sales device for convenient ready-to-cook food with internal temperature change suppression, characterized by including: a control unit that controls the cooling supply unit according to the temperature of each storage area confirmed by the sensor unit, thereby maintaining the temperature of each storage area within a preset temperature range for each storage area.

2. In Paragraph 1, A sales device for convenient ready-to-eat food that suppresses internal temperature change, further comprising a sensing unit positioned on the discharge area of ​​each of the first and second internal spaces to detect whether a convenient ready-to-eat food is located in the discharge area.

3. In Paragraph 2, The above-mentioned sensing unit is provided with a plurality of load-cell sensors disposed on the bottom surface of the discharge area of ​​the first and second internal spaces, and is characterized by detecting a load change of a certain level or higher applied to the bottom surface of each discharge area to detect whether a ready-to-cook food is located in each discharge area.

4. In Paragraph 3, The above control unit is characterized by controlling the cold heat supply unit to provide cold heat to a storage area corresponding to the discharge area for a preset time when the discharge of a ready-to-cook food is confirmed from a specific discharge area through the above detection unit, thereby suppressing internal temperature change in the ready-to-cook food sales device.

5. In Paragraph 4, The above control unit is, A control unit that controls a cold heat supply unit according to the detection result of the above-mentioned detection unit; and It includes an identification portion that stores information on the weight of all ready-to-cook foods stored in each storage area of ​​the first and second internal spaces, and identifies the ready-to-cook foods according to the weight of the ready-to-cook foods measured by the sensing portion; The above identification portion is characterized by having cooking information in the form of a data table in which the weight of each convenient ready-to-eat food and the cooking method of each convenient ready-to-eat food are matched and stored, in an internal temperature change suppression type convenient ready-to-eat food sales device.

6. In Paragraph 5, An internal temperature change suppression type convenient ready-to-cook food sales device further comprising: a display unit disposed on the outer surface of the door portion and outputting a cooking method of the convenient ready-to-cook food identified from the identification portion.

7. In Paragraph 5, A sales device for convenient ready-to-cook food that suppresses internal temperature changes, further comprising a monitoring unit that detects rotation of the opening / closing unit and monitors the opening / closing status of each storage area of ​​the opening / closing unit.

8. In Paragraph 7, The above control unit is characterized by controlling the cold heat supply unit to provide cold heat to the storage area corresponding to the discharge area for a preset time when a load change of a certain level or more is detected by at least one of the pair of sensing units, and only when it is confirmed through the monitoring unit that all opening and closing units are closing their respective storage areas.

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