JP2019011932A - Refrigerator and refrigerator temperature control method - Google Patents

Abstract

To provide a refrigerator capable of freezing and thawing a surface of a food product in a simple way, to reduce bacteria adhering to the surface of the food product, to thereby improve storage property of the food product, and a refrigerator temperature control method.SOLUTION: A refrigerator 1 comprises a changeover chamber 200 where objects to be cooled, a cooler 3 configured to cool the inside of the changeover chamber 200, and a controller 8 configured to control the cooler 3. The controller 8 causes the cooler 3 to repeatedly execute freezing and thawing processing containing a freezing step of freezing the surface of the object to be cooled, and a thawing step of thawing the surface of the object to be cooled having been frozen in the freezing step, and then execute a maintenance step of keeping a temperature of the changeover chamber 200 constant.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a refrigerator and a temperature control method of the refrigerator, and obtains an effect of reducing bacteria by freezing and thawing treatment and preserves an object to be cooled with high quality.

  The food sterilization method has been generally sterilized by heat for a long time, but since the flavor and texture of the food change when heated, fresh food such as raw meat or raw fish It is not preferable as a method to be performed during storage. As a sterilization method for these foods, non-heating is required.

  As one of such methods, an operation for maintaining the food in an antifreeze state of 0 ° C. or lower by pressurization and then changing the phase of the water in the food from the antifreeze region to ice crystals by further pressurization is performed. Or the method of repeating twice or more is proposed (patent document 1).

Japanese Patent Laid-Open No. 04-158773 (for example, Claim 1, Table 1)

However, since the technique described in Patent Document 1 needs to apply a high pressure of several thousand kg / cm ² , the pressurizing apparatus becomes large, and a pressure-resistant structure must be taken to perform the pressurizing process. Applying to a refrigerator is not realistic.

  The present invention has been made in order to solve the above-mentioned problems. By freezing and thawing the surface layer portion of the food with a simple configuration, the bacteria attached to the surface of the food can be reduced, and the food can be preserved. The purpose is to improve.

  A refrigerator according to an aspect of the present invention includes a storage chamber in which an object to be cooled is stored, a cooling unit that cools the storage chamber, and a control unit that controls the cooling unit, and the control unit includes: Freezing and thawing including: a first process for freezing a surface layer part of the object to be cooled in a cooling unit; and a second process for defrosting the surface layer part of the object to be cooled frozen by the first process. Processing is executed.

  The temperature control method for a refrigerator according to another aspect of the present invention includes a first step of freezing a surface layer portion of the object to be cooled, and a step of thawing the surface layer portion of the object to be cooled frozen in the first step. A freezing and thawing step including a second step.

  ADVANTAGE OF THE INVENTION According to this invention, the microbe adhering to the surface of foodstuffs can be reduced by freezing and thawing | decompressing the surface layer part of foodstuffs by simple structure, and the preservability of foodstuffs can be improved.

1 is a front view illustrating a schematic configuration of a refrigerator according to Embodiment 1. FIG. 1 is a longitudinal sectional view showing a schematic configuration of a refrigerator according to Embodiment 1. FIG. 3 is a cross-sectional view showing a schematic configuration of a switching chamber portion of the refrigerator according to Embodiment 1. FIG. 3 is a block diagram illustrating a schematic configuration of a control system of the refrigerator according to Embodiment 1. FIG. It is a figure which shows the time-dependent change of the setting temperature of the switching room which implemented temperature control of the refrigerator which concerns on Embodiment 1, the temperature in a store | warehouse | chamber, food center temperature, and food surface temperature. FIG. 3 is a schematic diagram illustrating a state of food in a switching room in which temperature control is performed in the first embodiment. FIG. 3 is a diagram showing a change with time of the number of E. coli attached to food in the first embodiment. 3 is a flowchart illustrating an example of processing of the refrigerator according to Embodiment 1. It is sectional drawing which shows the schematic structure of the switching chamber part of the refrigerator which concerns on Embodiment 2. FIG. 6 is a block diagram showing a schematic configuration of a control system of a refrigerator according to Embodiment 2. FIG. 6 is a cross-sectional view illustrating a schematic configuration of a switching chamber portion of a refrigerator according to Embodiment 3. FIG. 6 is a block diagram illustrating a schematic configuration of a control system of a refrigerator according to Embodiment 3. FIG. It is a figure which shows the time-dependent change of the setting temperature of the switching room which implemented temperature control in Embodiment 3, the temperature in a store | warehouse | chamber, food center temperature, and food surface temperature. 12 is a flowchart illustrating an example of processing of the refrigerator according to the third embodiment. It is sectional drawing which shows the schematic structure of the switching chamber part of the refrigerator which concerns on Embodiment 4. FIG. It is a block diagram which shows the schematic structure of the control system of the refrigerator which concerns on Embodiment 4. FIG. It is a figure which shows the time-dependent change of the preset temperature of the switching room which implemented temperature control in Embodiment 4, the temperature in a store | warehouse | chamber, food center temperature, and food surface temperature. 10 is a flowchart illustrating an example of processing of the refrigerator according to the fourth embodiment. It is sectional drawing which shows the schematic structure of the switching chamber part of the refrigerator which concerns on Embodiment 5. FIG. FIG. 6 is a refrigerant circuit diagram illustrating a schematic configuration of a refrigerator according to a fifth embodiment.

<< 1 >> Embodiment 1
<< 1-1 >> Configuration Hereinafter, the refrigerator 1 according to Embodiment 1 of the present invention will be described. FIG. 1 is a front view showing a schematic configuration of refrigerator 1 according to Embodiment 1. FIG. FIG. 2 is a longitudinal sectional view illustrating a schematic configuration of the refrigerator 1 according to the first embodiment. In the following drawings including FIG. 1 and FIG. 2, the dimensional relationship and shape of each component may differ from the actual ones. Moreover, the positional relationship (for example, up-down relationship etc.) of each structural member in a specification is a thing when installing a refrigerator in the usable state in principle. The refrigerator 1 is described as refrigerators 1a, 1b, 1c, and 1d in the second, third, fourth, and fifth embodiments, respectively.

  As shown in FIG. 1, the refrigerator 1 according to the first embodiment includes a refrigerating room 100 arranged at the uppermost stage as a plurality of storage rooms, a switching room 200 arranged below the refrigerating room 100, and switching. The ice making chamber 300 disposed in parallel with the switching chamber 200 adjacent to the side of the chamber 200, the freezing chamber 400 disposed below the switching chamber 200 and the ice making chamber 300, and disposed below the freezing chamber 400. And a lowermost vegetable room 500. The switching chamber 200 has various types such as a freezing temperature zone (for example, about −18 ° C.), a refrigeration temperature zone (for example, about 3 ° C.), a chilled temperature zone (for example, about 0 ° C.), and a soft freezing temperature zone (for example, about −7 ° C.). The cold insulation temperature zone can be switched to the temperature zone.

  As shown in FIG. 1, a rotary door 7 that opens and closes the opening is provided in the opening formed in the front surface of the refrigerator compartment 100. The door 7 of this example is of a double door type (double door type), and is composed of a right door 7a and a left door 7b. An operation panel 6 is provided on the outer surface of the door 7 (for example, the left door 7b) serving as the front surface of the refrigerator 1. The operation panel 6 includes an operation switch (an operation unit 6a to be described later with reference to FIG. 4) for adjusting settings such as the cold insulation temperature of each storage room, and a liquid crystal that displays the temperature of each storage room and inventory information in the storage. And a display unit (a display unit 6b described later with reference to FIG. 4). The operation panel 6 may include a touch panel that serves as both an operation unit and a display unit.

  Each storage room (the switching room 200, the ice making room 300, the freezer room 400, and the vegetable room 500) other than the refrigerator room 100 is opened and closed by a drawer-type door. These drawer-type doors slide in the depth direction (front-rear direction) of the refrigerator 1 by sliding a frame fixed to the door with respect to rails formed horizontally on the left and right inner wall surfaces of each storage room. It can be opened and closed.

  As shown in FIG. 2, the refrigerator 1 includes a heat insulating box 90 having a front surface (front) opened and a storage space formed therein. The heat insulation box 90 has a steel outer box, a resin inner box, and a heat insulating material filled in a space between the outer box and the inner box. The storage space formed inside the heat insulation box 90 is partitioned into a plurality of storage chambers for storing food by one or a plurality of partition members.

  As shown in FIG. 2, in the vegetable compartment 500, a storage case 501 capable of storing food and the like is stored so as to be freely drawn out. The storage case 501 is supported by the frame of the door 7, and slides in the front-rear direction in conjunction with opening and closing of the door 7. Similarly, in the switching chamber 200 and the freezer compartment 400, storage cases 201 and 401 that can store food and the like are stored in a freely retractable manner. The number of storage cases provided in each storage room may be one, but it may be two or more when the organization and the like are improved in consideration of the capacity of the entire refrigerator 1.

  As shown in FIG. 2, on the back side of the refrigerator 1, as a cooling mechanism for cooling each storage room, a compressor 2, a cooler 3, a blower fan 4, an air passage 5, and a control device. 8 are provided. The control device 8 includes a microcomputer, for example, and includes a CPU (Central Processing Unit) 8a and a memory 8b described later. The control device 8 controls the refrigerator 1 by executing a preset process when the CPU 8a executes a program stored in the memory 8b.

  The cold air produced by the compressor 2 and the cooler 3 is blown by the blower fan 4, passes through the air passage 5, and is blown to the freezing room 400, the switching room 200, the ice making room 300, and the refrigerating room 100. Cool the room. The vegetable room 500 is cooled by circulating the return cold air from the refrigerating room 100 from the return air passage for the refrigerating room, and then returned to the cooler 3 from the return air path for the vegetable room (return air path is not shown). The temperature of each room is detected by a thermistor 11 (shown in FIG. 3) installed in each room, and a switching room damper 12 (shown in FIG. 3) installed in the air passage 5 so as to have a preset temperature. And the output of the compressor 2 and the blowing amount of the blower fan 4 are controlled.

  FIG. 3 is a cross-sectional view illustrating a schematic configuration of the switching chamber 200 portion of the refrigerator 1 according to the first embodiment. As shown in FIG. 3, the switching chamber 200 includes a door opening / closing detection switch 10 that detects the open / closed state of the door 7 and a thermistor 11 that detects the temperature of the switching chamber 200. A switching chamber damper 12 is provided in the air passage 5 on the back side of the switching chamber 200. The temperature of the switching chamber 200 is controlled by adjusting the opening degree of the switching chamber damper 12 installed in the air passage 5.

  FIG. 4 is a block diagram illustrating a schematic configuration of a control system of the refrigerator 1 according to the first embodiment. In FIG. 4, the same components as those shown in FIGS. 1 to 3 are denoted by the same reference numerals. As shown in FIG. 4, the refrigerator 1 includes a compressor 2, a blower fan 4, an operation panel 6, a control device 8 as a control unit, a door open / close detection switch 10, a thermistor 11, and a switching chamber damper. 12 and a time measuring unit 30. The operation panel 6 includes an operation unit 6a and a display unit 6b. The control device 8 includes a CPU 8a and a memory 8b.

  As shown in FIG. 4, the control device 8 acquires the temperature of the switching chamber 200 from the thermistor 11. In addition, the control device 8 acquires the time measured by the time measuring unit 30. The control device 8 controls the operating states of the compressor 2, the blower fan 4, the switching chamber damper 12, and the like according to the operation program stored in advance in the memory 8b so that the switching chamber 200 is maintained at the set temperature. To do.

  As shown in FIG. 4, the control device 8 receives an operation signal from the operation unit 6 a of the operation panel 6 and outputs a display signal to the display unit 6 b of the operation panel 6. The control device 8 also receives a detection signal from the door opening / closing detection switch 10.

  FIG. 5 shows changes over time in the set temperature and internal temperature of the switching chamber 200 and the center temperature and surface temperature of food stored in the switching chamber 200 when the temperature control of the refrigerator 1 according to Embodiment 1 is performed. FIG. As shown in FIG. 5, the temperature control of the switching chamber 200 includes a freezing step (first processing), a freezing and thawing step (freezing and thawing processing) including a thawing step (second processing), and a maintenance step (first step). 3 processes).

  In FIG. 5, the center temperature of the food stored in the switching chamber 200 of the refrigerator 1 is shown by a thin solid line, and the surface temperature of the food stored in the switching chamber 200 of the refrigerator 1 (surface layer temperature) is It is indicated by a thick solid line, the internal temperature of the switching chamber 200 of the refrigerator 1 is indicated by a thin broken line, and the set temperature θs of the switching chamber 200 of the refrigerator 1 is indicated by a thick broken line.

  In the freezing and thawing process, the control device 8 starts the thawing process at the end of the freezing process and starts the freezing process at the end of the thawing process (for example, the compressor 2, the blower fan 4, the switching chamber damper). 12 etc.). The set temperature θs of the switching chamber 200 is provided separately for the freezing step and the thawing step. The set temperature θs of the switching chamber 200 is set to a low temperature set temperature θL lower than the freezing point θf of the food in the freezing process (cooling process), and higher than the freezing point θf of the food in the thawing process (heating process). The temperature rise set temperature θH is set.

  The low temperature set temperature θL is, for example, −20 ° C., and the temperature rise set temperature θH is, for example, 5 ° C. The low temperature set temperature θL is preferably in the range of −25 ° C. to −5 ° C., and the temperature rise set temperature θH is preferably in the range of 0 ° C. to 10 ° C.

  In the freezing process, the set temperature θs of the switching chamber 200 is set to the low temperature set temperature θL, and when the first predetermined time (freezing process time ΔTL) has elapsed (time TL), the freezing process is terminated and the thawing process is started. In the thawing process, the set temperature θs of the switching chamber 200 is switched to the temperature rise set temperature θH, and is maintained at the temperature rise set temperature θH for a second predetermined time (thawing process time ΔTH).

  When the thawing process time ΔTH has elapsed (time TH), the thawing process is terminated. The period from the start of the freezing process to the end of the thawing process is defined as one cycle, and the series of temperature control is repeated n times set in advance as the freeze thawing process. n is an integer of 1 or more, and preferably 2 or more. When the freeze-thaw process is completed (time TR), the maintenance process is started. In the maintenance step, the maintenance set temperature (first temperature) θR higher than the freezing point θf of the food is set, and the temperature of the switching chamber 200 is maintained at the maintenance set temperature θR.

  By performing the above control, as shown in FIG. 5, the surface temperature of the food stored in the refrigerator 1 is lowered to a temperature lower than the freezing point θf of the food by the freezing process, and the set temperature rise is performed by the thawing process. Repeat to rise to θH. On the other hand, the center temperature of the food stored in the refrigerator 1 is lowered to a temperature close to the freezing point θf of the food by the freezing process, and is repeatedly raised to the temperature rise set temperature θH by the thawing process. Therefore, since the central part of the food does not reach freezing, the quality of the food is maintained. On the other hand, the surface layer of the food is repeatedly frozen and thawed so that the bacteria attached to the surface layer are killed.

  FIG. 6 is a schematic diagram illustrating a change in the state of the food stored in the switching chamber 200 according to the first embodiment over time. In FIG. 6, the non-frozen state of the food is indicated by dark hatching, and the frozen state of the food is indicated by thin hatching. Further, time 0 to time TR in FIG. 6 coincides with time 0 to time TR in FIG.

  As shown in FIG. 6, at time 0, the food stored in the switching chamber 200 is in a non-freezing state and is cooled in the freezing process, and the temperature drops. At this time, since the food is cooled from the surface, the surface temperature falls earlier than the center temperature and reaches the freezing point θf or less. The food surface temporarily becomes a supercooled state where it does not freeze even when it is below the freezing point θf, but since the supercooled state is unstable in terms of energy, the supercooled state is immediately eliminated and the surface layer of the food Ice crystals are formed in the part and freezing starts. For this reason, at the time TL, the surface layer portion of the food is in a frozen state and the central portion is in a non-frozen state.

  Therefore, the process proceeds to a thawing process at a predetermined timing, and the temperature is raised to a temperature higher than the freezing point θf, so that the ice crystals generated in the surface layer part are thawed before freezing to the center of the food ( Thaw) to return to the non-frozen state. For this reason, at the time TH, both the surface layer and the inside of the food are in a non-frozen state. By repeating a series of temperature control in the freeze-thaw process shown in FIG. 5, the surface layer portion of the food is again frozen and the center portion is unfrozen (time TL1). When the freezing and thawing process ends, the process proceeds from time TR to the maintenance process, and the set temperature θs of the switching chamber 200 is maintained at the maintenance set temperature θR that is higher than the freezing point θf of the food.

  FIG. 7 is a diagram showing the change over time in the number of E. coli attached to food in the first embodiment. FIG. 7 shows the bacterium when stored for 20 hours under the conditions of freezing storage in a frozen state, refrigerated storage in a non-freezing state, and freezing and thawing repetition in which freeze-thaw phase change is repeatedly generated. It is for comparing changes in numbers. In FIG. 7, frozen storage is indicated by a square, refrigerated storage is indicated by a triangle, and repeated freeze-thaw is indicated by a rhombus. In FIG. 7, the vertical axis represents the number of bacteria (log (cfu)) attached to the food, and the horizontal axis represents time (h).

  As shown in FIG. 7, it can be seen that the number of bacteria hardly changes in frozen storage and refrigerated storage, whereas the number of bacteria decreases with time in repeated freeze-thawing. This is thought to be due to the fact that the bacteria are killed and the growth is suppressed because physical changes due to ice crystal formation, dehydration due to the concentration of the cell fluid, etc. occur and damage the cell membrane of the bacteria. Therefore, by causing the phase change state repeatedly in the surface layer portion of the food by the temperature control shown in FIG. 5, it is possible to suppress the growth of bacteria on the surface layer portion.

  In many cases, bacteria that cause food spoilage and the like adhere to the food processing process, and most of them are present on the surface of the food. Therefore, by freezing and thawing the surface layer portion of the food, it is possible to obtain the effect of suppressing the growth of bacteria, and it is possible to suppress deterioration such as rot of the food. In addition, by freezing and thawing only the surface layer of the food and causing no phase change in the center (inside) of the food, damage to the cells of the food by ice crystals can be minimized. , Quality such as texture, flavor can be maintained.

  Here, the temperature control performed by the refrigerator 1 according to Embodiment 1 is particularly effective for preserving foods that do not have cell walls such as meat and fish. This is because such foods have a flexible cell membrane, so that the influence on food quality due to freezing and thawing of the surface layer is particularly small. Thus, maintenance of food quality and suppression of bacterial growth can be achieved at the same time, and the quality retention period of food can be extended.

By repeating the phase change as many times as necessary for the reduction of the bacteria, and thereafter performing the maintenance step, damage to the cells of the food can be minimized. It is known that bacteria attached to food are 10 ² to 10 ⁶ (cfu: colony forming unit) as long as they are sold on the market. Therefore, the number of times to reduce the number of bacteria can be obtained in advance through experiments or the like and set in the refrigerator 1.

<< 1-2 >> Operation Hereinafter, a temperature control method performed by the refrigerator 1 according to Embodiment 1 will be described. FIG. 8 is a flowchart illustrating an example of processing of the refrigerator 1 according to the first embodiment. When the refrigerator 1 is turned on or selected by the operation panel 6, the temperature control according to the first embodiment is started. First, the counter i = 0 is set (S101). Subsequently, the time t = 0 is set (S102), the set temperature θs is set to the low temperature set temperature θL (for example, −20 ° C.), and the freezing step (first step) is started (S103). Subsequently, the time t (elapsed time) of the freezing process is measured (S104).

  When a preset time ΔTL (for example, 30 minutes) has elapsed (Yes in S104), the freezing process is terminated, and the thawing process (second step) is started. In the thawing step, the time t is set to 0 (S105), and the set temperature θs is set to the temperature rise set temperature θH (for example, 5 ° C.) (S106).

  When a preset thawing process time ΔTH (for example, 40 minutes) elapses (Yes in S107), 1 is added to the counter i (S108), and the thawing process is terminated until n times (for example, n = 10). Then, the freezing step is performed again, and a series of temperature control is repeated (yes in S109). When the counter i is added and the number of times reaches n (no in S109), the freeze-thaw process is terminated, and the set temperature θs is set to the maintenance set temperature θR (for example, 0 ° C.) and maintained (S110).

  In the thawing process, the switching chamber damper 12 is closed to stop the inflow of cold air, and the internal temperature of the switching chamber 200 is raised. In the thawing step, the internal temperature of the switching chamber 200 may be increased by operating the blower fan 4 when the compressor 2 is stopped and opening the switching chamber damper 12 to circulate air.

  In the above description, the maintenance set temperature θR in the maintenance process is set to a temperature higher than the freezing point θf of the food, but may be set to a temperature (second temperature) lower than the freezing point θf of the food. In this case, the food can be stored for a longer period, such as one month or longer.

<< 1-3 >> Effect According to the refrigerator 1 according to the first embodiment, the freezing and thawing process including the freezing process for freezing the surface part (surface) of the food and the thawing process for thawing the frozen surface part is repeated. After that, a maintenance process is performed to keep the temperature of the food constant. Thereby, the microbe adhering to the surface layer part of foodstuffs can be reduced, and the preservability of foodstuffs can be improved. In addition, since the central portion of the food is not frozen, the food can last for a long time, and the food can be immediately cut and cooked with a kitchen knife, which improves convenience.

<< 1-4 >> Modifications In the above description, the freezing process is a process in which only the surface layer part of the food is frozen and the central part is not frozen, but the freezing process is a process of freezing the food to the central part. It is also possible to defrost the center. In this case, it is conceivable that not only the bacteria present in the surface layer of the food but also the bacteria present in the central part of the food are sterilized by undergoing a freeze-thaw process for the central part of the food.

<< 2 >> Embodiment 2
Hereinafter, the refrigerator 1a which concerns on Embodiment 2 of this invention is demonstrated. FIG. 9 is a cross-sectional view illustrating a schematic configuration of switching room 200a of refrigerator 1a according to the second embodiment. FIG. 10 is a block diagram illustrating a schematic configuration of a control system of the refrigerator 1a according to the second embodiment. 9 and 10, the same parts as those in the first embodiment are denoted by the same reference numerals, and a part of the description is omitted.

  As shown in FIGS. 9 and 10, in the refrigerator 1a according to the second embodiment, the heater 13 is embedded as a heating mechanism (heating unit) that heats the switching chamber 200a and raises the temperature below the switching chamber 200a. It differs from the refrigerator 1 which concerns on Embodiment 1 in the point. By installing the heater 13 below the switching chamber 200a, it is possible to efficiently raise the temperature of the switching chamber 200a. The control device 8 acquires the temperature in the switching chamber 200a from the thermistor 11, and sets the heater 13 in a heated state when the temperature of the switching chamber 200a is equal to or lower than a preset temperature.

  Moreover, the control apparatus 8 cancels | releases the heater 13 from a heating state, when the temperature of the switching chamber 200a becomes more than the preset temperature. The control device 8 acquires the temperature of the switching chamber 200a from the thermistor 11, and the compressor 2, the blower fan 4, and the like in accordance with a program stored in advance in the memory 8b so that the inside of the switching chamber 200 is maintained at the set temperature. The operation state of the switching chamber damper 12, the heater 13, etc. is controlled.

  In the above description, the control device 8 is described as controlling the heater 13 in addition to the control of the switching chamber damper 12 and the like in the thawing process, but the control method is not particularly limited thereto. For example, the control device 8 may raise the temperature of the switching chamber 200a by controlling the heater 13 without controlling the switching chamber damper 12 or the like in the thawing step.

  According to the refrigerator 1a according to Embodiment 2, the switching chamber 200a can be efficiently heated by installing the heater 13 below the switching chamber 200a. Therefore, the refrigerator 1a can perform the thawing | decompression process at high speed compared with the refrigerator which concerns on Embodiment 1, and can perform the freezing / thawing process of the surface layer part of a foodstuff efficiently.

<< 3 >> Embodiment 3
Hereinafter, the refrigerator 1b which concerns on Embodiment 3 of this invention is demonstrated. FIG. 11 is a cross-sectional view showing a schematic configuration of switching room 200b of refrigerator 1b according to Embodiment 3. FIG. 12 is a block diagram illustrating a schematic configuration of a control system of the refrigerator 1b according to the third embodiment. 11 and 12, the same parts as those in the first and second embodiments are denoted by the same reference numerals, and a part of the description is omitted.

  As shown in FIG. 11, the refrigerator 1b according to Embodiment 3 is provided with a cooling plate 14 on which food can be placed on the floor surface of the switching chamber 200b. Below the cooling plate 14, the heater 13 and the wind It differs from the refrigerators 1 and 1a which concern on Embodiment 1, 2 in the point by which the floor surface air path 15 which can flow in the cold air from the path 5 is provided. The cold air flow into the floor air passage 15 is performed by adjusting the opening degree of the floor air passage damper 16. The cold air flowing into the floor air passage 15 cools the cooling plate 14 and is returned to the cooler 3 through a return air passage (not shown). As shown in FIG. 12, the control device 8 controls the heater 13 and the floor air path damper 16.

  13 shows the temperature of the cooling plate 14 of the switching chamber 200b of the refrigerator 1b according to the third embodiment, the change over time in the center temperature and the surface temperature of the food stored in the switching chamber 200, and the floor air path damper 16 It shows the opening and closing and the ON / OFF state of the heater 13. As shown in FIG. 13, the temperature control of the cooling plate 14 in the switching chamber 200b includes a freezing and thawing process including a freezing process (first process), a thawing process (second process), and a maintenance process (third process). 3).

  In the freezing step, the floor air duct damper 16 is opened to allow cold air to flow into the floor air duct 15, and the temperature of the cooling plate 14 is quickly lowered. When the freezing process time ΔTL elapses (time TL), the freezing process is terminated and the thawing process is started. In the thawing process, the floor air path damper 16 is closed, the floor air path 15 is closed, the heater 13 is turned on, and the temperature of the cooling plate 14 is quickly raised. When the thawing process time ΔTH has elapsed (time TH), the thawing process is terminated.

  The period from the start of the freezing process to the end of the thawing process is defined as one cycle, and the series of temperature control is repeated n times set in advance as the freeze thawing process. The time for one cycle of the freeze-thaw process is set, for example, between 30 minutes and 90 minutes. When the freeze-thaw process is completed (time TR), the maintenance process is started. In the maintenance process, the floor air path damper 16 is closed and the heater 13 is turned off. In the maintenance process, the switching chamber damper 12 is adjusted so that the temperature of the switching chamber 200b is maintained at the maintenance set temperature θR.

  The temperature control of the switching chamber 200b may be performed so as to maintain the same maintenance set temperature θR through the freezing process, the thawing process, and the maintenance process. Further, different set temperatures may be provided in the freezing step, the thawing step, and the maintaining step.

  FIG. 14 is a flowchart illustrating an example of processing of the refrigerator 1b according to the third embodiment. When the refrigerator 1b is powered on or selected by the operation panel 6, the temperature control according to the first embodiment is started. Counter i = 0 is set (S301). At time t = 0 (S302), the floor air path damper 16 is opened (S303), the heater 13 is turned off (S304), and the freezing process is started. When the time t elapses for a preset time ΔTL (for example, 20 minutes) (yes in S305), the freezing process is terminated and the thawing process is started.

  In the thawing process, the time t is set to 0 (S306), the floor air path damper 16 is closed (S307), and the heater 13 is turned on (S308). When the set thawing process time ΔTH (for example, 30 minutes) has elapsed (Yes in S309), 1 is added to the counter i (S310), the thawing process is terminated, and until n times (for example, n = 10), The freezing process is performed again, and a series of temperature control is repeated (yes in S311). When the number of repetitions reaches n times (no in S311), the freeze-thaw process is terminated, the floor air path damper 16 is closed (S312), the heater 13 is turned off (S313), and the process proceeds to the maintenance process.

  According to the refrigerator 1b according to the third embodiment, the food can be efficiently frozen by providing the cooling plate 14 on which the food can be placed on the floor surface of the switching chamber 200b. Further, by providing the heater 13 and the floor air passage 15 below the cooling plate 14, the inside of the switching chamber 200b can be efficiently cooled or heated.

<< 4 >> Embodiment 4
Hereinafter, the refrigerator 1c which concerns on Embodiment 4 of this invention is demonstrated. FIG. 15 is a cross-sectional view illustrating a schematic configuration of switching room 200c of refrigerator 1c according to the fourth embodiment. FIG. 16 is a block diagram illustrating a schematic configuration of a control system of the refrigerator 1c according to the fourth embodiment. The same parts as those in the first to third embodiments are denoted by the same reference numerals, and a part of the description is omitted.

  As shown in FIG. 15, the refrigerator 1c according to the fourth embodiment is provided with a cooling plate 14 on which food can be placed on the floor surface of the switching chamber 200c, and with a Peltier element 17 below the cooling plate 14. It differs from the refrigerator 1, 1a, 1b which concerns on Embodiment 1-3 in the point which is. The refrigerator 1c according to the fourth embodiment is provided with a drive device (not shown) that can switch the direction of current flowing through the Peltier element 17 between the heat radiation side and the heat absorption side. As shown in FIG. 16, the control device 8 is connected to the Peltier element 17 and controls the drive device so as to switch the current direction between the freezing step and the thawing step.

  FIG. 17 shows the temperature of the cooling plate 14 of the switching chamber 200c of the refrigerator 1c according to the fourth embodiment, the change over time in the center temperature and the surface temperature of the food stored in the switching chamber 200, and the state of the Peltier element 17. FIG.

  As shown in FIG. 17, in the freezing step, the Peltier element 17 is energized to the heat absorption side to cool the cooling plate 14. When the freezing process time ΔTL elapses (time TL), the freezing process is terminated and the thawing process is started. In the thawing step, the cooling plate 14 is heated by energizing the Peltier element 17 to the heat dissipation side. When the thawing process time ΔTH has elapsed (time TH), the thawing process is terminated. In the maintenance step, the Peltier element 17 is turned off without energization, the switching chamber damper 12 is adjusted so that the temperature of the switching chamber 200c is maintained at the maintenance set temperature θR, and the temperature of the cooling plate 14 is also set in the switching chamber 200c. Follow the temperature.

  The temperature control of the switching chamber 200 may be performed so as to maintain the same maintenance set temperature θR through the freezing process, the thawing process, and the maintenance process. Further, different set temperatures may be provided in the freezing step, the thawing step, and the maintaining step.

  FIG. 18 is a flowchart illustrating an example of processing of the refrigerator 1c according to the fourth embodiment. When the refrigerator 1 is turned on or selected by the operation panel 6, the temperature control in the fourth embodiment is started. First, the counter i = 0 is set (S401). Subsequently, at time t = 0 (S402), the Peltier element 17 is energized to the heat absorption side (S403), and the freezing process is started. When the time t elapses for a preset time ΔTL (for example, 20 minutes) (yes in S404), the freezing process is terminated and the thawing process is started.

  In the thawing step, time t is set to 0 (S405), and the Peltier element 17 is energized to the heat radiating side (S406). When the set thawing process time ΔTH (for example, 30 minutes) has elapsed (Yes in S407), 1 is added to the counter i (S408), the thawing process is terminated, and until n times (for example, n = 10), The freezing process is performed again, and a series of temperature control is repeated (yes in S409). When the number of repetitions reaches n (no in S409), the freeze-thaw process is terminated, the power supply to the Peltier element 17 is turned off (S410), and the process proceeds to the maintenance process.

  According to the refrigerator 1c according to the fourth embodiment, the cooling plate 14 and the Peltier element 17 are provided on the floor surface of the switching chamber 200c, and a current is supplied to the heat radiation side and the heat absorption side of the Peltier element 17 so that the cooling plate 14 Cool or heat. Thereby, the foodstuff in the switching chamber 200c can be efficiently frozen or thawed.

<< 5 >> Embodiment 5
Hereinafter, the refrigerator 1d which concerns on Embodiment 5 of this invention is demonstrated. FIG. 19 is a cross-sectional view illustrating a schematic configuration of switching room 200d of refrigerator 1d according to the fifth embodiment. FIG. 20 is a diagram illustrating a schematic configuration of the refrigerant circuit of the refrigerator 1d according to the fifth embodiment. The same parts as those in the first to fourth embodiments are denoted by the same reference numerals, and a part of the description is omitted.

  As shown in FIG. 19, in the refrigerator 1 d according to the fifth embodiment, a cooling plate 14 on which food can be placed is provided on the floor surface of the switching chamber 200 d, and a switching chamber control pipe 18 is provided below the cooling plate 14. In the point provided, it differs from the refrigerator 1, 1a, 1b, 1c which concerns on Embodiment 1-4. The switching chamber control pipe 18 is branched from the main circuit 24 that controls the refrigerator 1d. The switching chamber control pipe 18 cools the cooling plate 14 by switching the three-way valves 19, 25, and 26. Or heating.

  As shown in FIG. 20, the refrigeration cycle includes a compressor 2, a three-way valve 19, a condenser 20, a dryer 21, a capillary tube 22, a cooler 3, a header 23, and a suction pipe 27 in this order. And the suction pipe 27 are constituted by a main circuit 24 for heat exchange. A switching chamber control pipe 18 branched from the three-way valve 19 and branched to the three-way valves 25 and 26 and connected to the bypass circuit 28 is provided.

  In the freezing process, the main circuit 24 in the order of the compressor 2, the three-way valve 19, the condenser 20, the dryer 21, the capillary 22, and the cooler 3 is used to exit the cooler 3, and then the header 23, the three-way valve 25, The three-way valves 19, 25, and 26 are controlled so that the switching chamber control pipe 18, the three-way valve 26, and the suction pipe 27 are arranged in this order. At this time, since the low-temperature gas flows through the switching chamber control pipe 18, the cooling plate 14 can be sufficiently cooled.

  In the thawing process, the three-way valves 19, 25, and 26 are controlled so that the compressor 2, the three-way valve 19, the switching chamber control pipe 18, and the three-way valve 26 are arranged in this order. At this time, since the high-temperature gas flows through the switching chamber control pipe 18, the cooling plate 14 can be sufficiently heated. After the freezing step and the thawing step are repeated a predetermined number of times, the maintenance step is started. In the maintenance process, the three-way valves 19, 25, and 26 are controlled so that the switching chamber control pipe 18 is disconnected. The cooling means in the freezing step and the heating means in the thawing step are not limited to one means, and a plurality of means may be combined or a plurality of means may be switched.

  According to the refrigerator 1d according to the fifth embodiment, the cooling plate 14 on which food can be placed is provided on the floor surface of the switching chamber 200d, and the switching chamber control pipe 18 is provided below the cooling plate 14. Thereby, the food in the switching chamber 200d can be efficiently frozen or thawed.

  1, 1a, 1b, 1c, 1d Refrigerator, 2 Compressor, 3 Cooler, 4 Blower, 5 Air channel, 6 Operation panel, 7 Door, 7a Right door, 7b Left door, 8 Control device, 8a Processor, 8b Memory, 10 Door open / close detection switch, 11 Thermistor, 12 Switching chamber damper, 13 Heater, 14 Cooling plate, 15 Floor air channel, 16 Floor air channel damper, 17 Peltier element, 18 Switching chamber control piping, 19 Three-way valve, 20 condensers, 21 dryers, 22 capillaries, 23 headers, 24 main circuits, 25, 26 three-way valves, 27 suction pipes, 28 bypass circuits, 30-hour measuring units, 90 heat insulation boxes, 100 refrigerator compartments, 200, 200a, 200b , 200c, 200d switching room, 300 ice making room, 400 freezing room, 500 Vegetables chamber, 201,401,501 storage case.

Claims (13)

A storage room for storing the object to be cooled;
A cooling unit for cooling the storage chamber;
A control unit for controlling the cooling unit,
The control unit is connected to the cooling unit,
A freezing and thawing process including a first process for freezing a surface layer part of the object to be cooled and a second process for thawing the surface layer part of the object to be cooled frozen by the first process is executed. A refrigerator characterized by that. The control unit is connected to the cooling unit,
The refrigerator according to claim 1, wherein the freeze-thaw process is repeatedly executed twice or more. The said control part controls preset temperature and preset time so that the center part which is parts other than the said surface layer part of the said to-be-cooled object may not be frozen in a said 1st process. Refrigerator. The said control part controls preset temperature and preset time so that the center part which is parts other than the said surface layer part of the said to-be-cooled object may be frozen in a said 1st process. Refrigerator. The control unit is connected to the cooling unit,
5. The third process of maintaining the temperature in the storage chamber at a first temperature higher than the freezing point of the object to be cooled is performed after the completion of the freeze-thaw process. The refrigerator of Claim 1. The control unit is connected to the cooling unit,
5. The fourth process for maintaining the temperature in the storage chamber at a second temperature lower than the freezing point of the object to be cooled is performed after the completion of the freeze-thaw process. The refrigerator of Claim 1. A heating unit for heating the storage chamber;
The controller is
The said 2nd process WHEREIN: The said heating part is controlled so that the temperature in the said storage chamber becomes a temperature higher than the freezing point of the said to-be-cooled object. Any one of Claim 1 to 6 characterized by the above-mentioned. The refrigerator described. The refrigerator according to claim 7, wherein the heating unit includes a heater. The cooling part is
A refrigerator according to any one of claims 1 to 8, comprising a Peltier element. The refrigerator according to any one of claims 1 to 9, wherein the cooling unit includes a cooling plate that mounts and cools the object to be cooled. The set temperature of the first treatment is in the range of −25 ° C. to −5 ° C.,
11. The refrigerator according to claim 1, wherein a set temperature of the second treatment is in a range of 0 ° C. to 10 ° C. 11. A time measurement unit;
The said control part controls the time of one period of the said freeze-thaw process within the range of 30 minutes to 90 minutes based on the time measured by the said time measurement part. The refrigerator of any one. A freezing and thawing step including a first step of freezing a surface layer portion of the object to be cooled and a second step of thawing the surface layer portion of the object to be cooled frozen in the first step. A temperature control method for a refrigerator.

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