JP6995511B2 - Refrigerator and refrigerator temperature control method - Google Patents

Description

The present invention relates to a refrigerator and a method for controlling the temperature of the refrigerator, in which the effect of reducing bacteria is obtained by freeze-thaw treatment, and the object to be cooled is stored in high quality.

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

As one of such methods, an operation of holding the food in an antifreeze state of 0 ° C. or lower by pressurization and then changing the phase of water in the food from the antifreeze region to ice crystals by further pressurization is 1 Alternatively, a method of repeating the process twice or more has been proposed (Patent Document 1).

JP-A-04-158773 (for example, claim 1, Table 1)

However, since the technique described in Patent Document 1 requires applying a high pressure of several thousand kg / cm ² , the pressurizing device becomes large, and a pressure-resistant structure must be adopted for pressurizing. , It is not realistic to apply it to the refrigerator.

The present invention has been made to solve the above-mentioned problems, and by freezing and thawing the surface layer of food with a simple structure, bacteria adhering to the surface of food are reduced and the food is preserved. The purpose is to improve.

The refrigerator according to one aspect of the present invention includes a storage chamber in which the object to be cooled is stored, a cooling unit having a cooling cycle for cooling the storage chamber, and a control unit for controlling the cooling unit. The unit is a first process of freezing only the surface layer portion of the object to be cooled by the cooling unit, and a second process of thawing only the surface layer portion of the object to be cooled frozen by the first process. The freeze-thaw process including the above is repeatedly executed twice or more, and the control unit sets the temperature and the set temperature so as not to freeze the central portion of the object to be cooled other than the surface layer portion in the first process. It is characterized by controlling the set time.

A method of controlling the temperature of a refrigerator according to another aspect of the present invention is a temperature control performed by a refrigerator provided with a storage chamber in which an object to be cooled is stored and a cooling unit having a refrigerating cycle for cooling the storage chamber. The second method is to allow the cooling unit to freeze only the surface layer portion of the object to be cooled, and to thaw only the surface layer portion of the object to be cooled frozen by the first treatment. In the first process, the temperature is set so as not to freeze the central portion of the object to be cooled, which is a portion other than the surface layer portion. And control the set time.

According to the present invention, by freezing and thawing the surface layer portion of a food with a simple structure, bacteria adhering to the surface of the food can be reduced and the preservability of the food can be improved.

It is a front view which shows the schematic structure of the refrigerator which concerns on Embodiment 1. FIG. It is a vertical sectional view which shows the schematic structure of the refrigerator which concerns on Embodiment 1. FIG. It is sectional drawing which shows the schematic structure of the switching chamber part of the refrigerator which concerns on Embodiment 1. FIG. It is a block diagram which shows the schematic structure of the control system of the refrigerator which concerns on Embodiment 1. FIG. It is a figure which shows the time-dependent change of the set temperature of the switching room which carried out the temperature control of the refrigerator which concerns on Embodiment 1, the temperature in a refrigerator, the temperature of a food center, and the temperature of a food surface. It is a schematic diagram which shows the state of the food in the switching room which carried out the temperature control in Embodiment 1. FIG. It is a figure which shows the time-dependent change of the number of Escherichia coli adhering to the food in Embodiment 1. FIG. It is a flowchart which shows an example of the processing of the refrigerator which concerns on Embodiment 1. FIG. It is sectional drawing which shows the schematic structure of the switching chamber part of the refrigerator which concerns on Embodiment 2. FIG. It is a block diagram which shows the schematic structure of the control system of the refrigerator which concerns on Embodiment 2. FIG. It is sectional drawing which shows the schematic structure of the switching chamber part of the refrigerator which concerns on Embodiment 3. FIG. It is a block diagram which shows the schematic structure of the control system of the refrigerator which concerns on Embodiment 3. FIG. It is a figure which shows the time-dependent change of the set temperature, the inside temperature, the food center temperature, and the food surface temperature of the switching chamber which carried out the temperature control in Embodiment 3. FIG. It is a flowchart which shows an example of the processing of the refrigerator which concerns on Embodiment 3. 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 set temperature, the inside temperature, the food center temperature, and the food surface temperature of the switching chamber which carried out the temperature control in Embodiment 4. FIG. It is a flowchart which shows an example of the processing of the refrigerator which concerns on Embodiment 4. It is sectional drawing which shows the schematic structure of the switching chamber part of the refrigerator which concerns on Embodiment 5. It is a refrigerant circuit diagram which shows the schematic structure of the refrigerator which concerns on Embodiment 5.

<< 1 >> Embodiment 1
<< 1-1 >> Configuration The refrigerator 1 according to the first embodiment of the present invention will be described below. FIG. 1 is a front view showing a schematic configuration of the refrigerator 1 according to the first embodiment. FIG. 2 is a vertical sectional view showing a schematic configuration of the refrigerator 1 according to the first embodiment. In the following drawings including FIGS. 1 and 2, the dimensional relationship, shape, and the like of each constituent member may differ from the actual ones. In addition, the positional relationship between the constituent members (for example, the vertical relationship, etc.) in the specification is, in principle, when the refrigerator is installed in a usable state. 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 switches between a refrigerating chamber 100 arranged at the uppermost stage and a switching chamber 200 arranged below the refrigerating chamber 100 as a plurality of storage chambers. The ice making chamber 300 arranged in parallel with the switching chamber 200 adjacent to the side of the chamber 200, the freezing chamber 400 arranged below the switching chamber 200 and the ice making chamber 300, and the freezing chamber 400 arranged below the freezing chamber 400. It is equipped with a vegetable compartment 500 at the bottom. The switching chamber 200 has various types such as a freezing temperature zone (for example, about -18 ° C.), a refrigerating 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.). It is possible to switch the cold insulation temperature zone to the temperature zone.

As shown in FIG. 1, the opening formed in the front surface of the refrigerating chamber 100 is provided with a rotary door 7 for opening and closing the opening. The door 7 of this example is 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) which is the front surface of the refrigerator 1. The operation panel 6 has an operation switch (operation unit 6a described later in FIG. 4) for adjusting the setting of the cold insulation temperature of each storage room, and a liquid crystal display displaying the temperature of each storage room and the inventory information in the refrigerator. It is provided with a display unit (display unit 6b described later in FIG. 4). Further, the operation panel 6 may be provided with a touch panel that also serves as an operation unit and a display unit.

Each storage room (switching room 200, ice making room 300, freezing room 400, vegetable room 500) other than the refrigerating room 100 is opened and closed by a drawer-type door. In these drawer-type doors, the frame provided fixed to the door is slid with respect to the rails horizontally formed on the left and right inner wall surfaces of each storage chamber, so that the refrigerator 1 is in the depth direction (front-back direction). It can be opened and closed.

As shown in FIG. 2, the refrigerator 1 has a heat insulating box body 90 having a front surface (front surface) opened and a storage space formed inside. The heat insulating box body 90 has a steel outer box, a resin inner box, and a heat insulating material filled in the space between the outer box and the inner box. The storage space formed inside the heat insulating box 90 is divided 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 or the like inside is freely retractably stored. The storage case 501 is supported by the frame of the door 7 and slides in the front-rear direction in conjunction with the opening and closing of the door 7. Similarly, in the switching chamber 200 and the freezing chamber 400, storage cases 201 and 401 that can store food and the like inside are freely retractably stored, respectively. The number of storage cases provided in each storage room may be one, but may be two or more if the capacity of the entire refrigerator 1 is taken into consideration and the organization is improved.

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

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, respectively. Cool the room. The vegetable compartment 500 is cooled by circulating the return cold air of the refrigerator compartment 100 from the return air passage for the refrigerating chamber, and is returned to the cooler 3 from the return air passage for the vegetable chamber (the return air passage is not shown). The temperature of each room is detected by the thermistor 11 (shown in FIG. 3) installed in each room, and the switching chamber damper 12 (in FIG. 3) installed in the air passage 5 so as to reach a preset temperature. It is controlled by adjusting the opening degree (shown), the output of the compressor 2, and the air volume of the air blower fan 4.

FIG. 3 is a cross-sectional view showing a schematic configuration of a switching chamber 200 portion of the refrigerator 1 according to the first embodiment. As shown in FIG. 3, the switching chamber 200 is provided with a door opening / closing detection switch 10 for detecting the open / closed state of the door 7 and a thermistor 11 for detecting the temperature of the switching chamber 200. Further, 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 showing a schematic configuration of the 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 designated 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 are provided. 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. Further, the control device 8 acquires the time measured by the time measuring unit 30. The control device 8 controls the operating state of the compressor 2, the blower fan 4, the switching chamber damper 12, etc. according to the operation program stored in advance in the memory 8b so that the inside of the switching chamber 200 is maintained at the set temperature. do.

As shown in FIG. 4, an operation signal is input to the control device 8 from the operation unit 6a of the operation panel 6, and a display signal is output to the display unit 6b of the operation panel 6. Further, a detection signal or the like from the door open / close detection switch 10 is also input to the control device 8.

FIG. 5 shows changes over time in the set temperature and the internal temperature of the switching chamber 200 and the central temperature and the surface temperature of the food stored in the switching chamber 200 when the temperature of the refrigerator 1 according to the first embodiment is controlled. It is a figure which shows. As shown in FIG. 5, the temperature control of the switching chamber 200 includes a freeze-thaw step (freeze-thaw process) consisting of a freezing step (first process), a thawing step (second process), and a maintenance step (first process). It is composed of three steps of 3).

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

In the freeze-thaw step, the control device 8 starts the thawing step at the end of the freezing step, and the cooling mechanism (for example, the compressor 2, the blower fan 4, and the switching chamber damper) starts the freezing step at the end of the thawing step. 12 etc.) is controlled. The set temperature θs of the switching chamber 200 is separately provided 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 step (cooling step), and higher than the freezing point θf of the food in the thawing step (heating step). 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 step, 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 step time ΔTL) has elapsed (time TL), the freezing step is terminated and the thawing step is started. In the thawing step, 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 the second predetermined time (thawing step time ΔTH).

When the thawing step time ΔTH has elapsed (time TH), the thawing step is completed. One cycle is from the start of the freezing step to the end of the thawing step, and the freezing and thawing step is from repeating this series of temperature control n times preset. n is an integer of 1 or more, and is 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 step, and the temperature is set to be raised by the thawing step. Repeat going up to θH. On the other hand, the central 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 step, and is repeatedly raised to the temperature rise set temperature θH by the thawing step. Therefore, the central part of the food does not reach freezing, so that the quality of the food is maintained, while the surface layer part of the food is repeatedly frozen and thawed to kill the bacteria adhering to the surface layer part.

FIG. 6 is a schematic diagram showing changes over time in the state of food stored in the switching chamber 200 in the first embodiment. In FIG. 6, the non-frozen state of food is indicated by dark hatching, and the frozen state of food is indicated by light hatching. Further, the time TR from time 0 in FIG. 6 coincides with the time TR from time 0 in FIG.

As shown in FIG. 6, at time 0, the food stored in the switching chamber 200 is in a non-frozen state, and is cooled in the freezing step to lower the temperature. At this time, since the food is cooled from the surface, the surface temperature drops earlier than the center temperature and reaches the freezing point θf or less. The surface of food temporarily becomes a supercooled state that does not freeze even below the freezing point θf, but since the supercooled state is an energetically unstable state, the supercooled state is immediately resolved and the surface layer of the food Ice crystals are formed in the part and start freezing. Therefore, at 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, by shifting to the thawing step at a predetermined timing and raising the temperature to a temperature higher than the freezing point θf, the ice crystals formed on the surface layer portion are thawed (before the freezing progresses to the center of the food). Thaw) to return to the non-frozen state. Therefore, at time TH, both the surface layer portion and the inside of the food are in a non-frozen state. By repeating the series of temperature control of the freeze-thaw step shown in FIG. 5, the surface layer portion of the food becomes a frozen state and the central portion becomes a non-frozen state (time TL1). When the freeze-thaw step is completed, the time TR shifts to the maintenance step, and the set temperature θs of the switching chamber 200 is maintained at the maintenance set temperature θR higher than the freezing point θf of the food.

FIG. 7 is a diagram showing changes over time in the number of Escherichia coli attached to food in the first embodiment. FIG. 7 shows the bacteria of Escherichia coli when stored for 20 hours under the conditions of frozen storage stored in a frozen state, refrigerated storage stored in a non-frozen state, freezing and thawing that repeatedly caused phase changes in freezing and thawing. 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 diamond. Further, in FIG. 7, the vertical axis shows the number of bacteria attached to the food (log (cfu)), and the horizontal axis shows the time (h).

As shown in FIG. 7, it can be seen that the number of bacteria hardly changes between the frozen storage and the refrigerated storage, whereas the number of bacteria decreases with the passage of time in the repeated freeze-thaw. It is considered that this is because physical changes due to ice crystal formation, dehydration due to concentration of cell fluid, etc. occur and the cell membrane of the bacteria is damaged, so that the bacteria are killed and the growth is suppressed. Therefore, by repeatedly causing a phase change state 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.

Most of the bacteria that cause food spoilage are present on the surface of food because they are often attached during the processing process of food. Therefore, by freeze-thawing the surface layer portion of the food, the effect of suppressing the growth of bacteria can be obtained, and deterioration such as spoilage of the food can be suppressed. In addition, by freezing and thawing only the surface layer of the food and not causing a phase change in the center (inside) of the food, damage to the cells of the food due to ice crystals can be minimized, and the ingredients of the food can be minimized. It is possible to maintain quality such as texture and flavor.

Here, the temperature control performed by the refrigerator 1 according to the first embodiment is particularly effective for preserving foods having no cell wall such as meat and fish. This is because the cell membrane of such foods is flexible, so that the effect of freezing and thawing of the surface layer on food quality is particularly small. In this way, it is possible to achieve both maintenance of food quality and suppression of bacterial growth, and it is possible to extend the quality retention period of food.

By repeating the phase change as many times as necessary to reduce the number of bacteria and then performing the maintenance step, damage to the cells of the food can be minimized. It is known that the bacteria adhering to foods are 10 ² to ¹⁰⁶ (cfu: colony forming unit) if the foods are sold on the market. Therefore, the number of times to reduce the number of bacteria can be determined in advance by an experiment or the like and set in the refrigerator 1.

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

When the preset time ΔTL (for example, 30 minutes) has elapsed (yes in S104), the freezing step is terminated and the thawing step (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 the preset defrosting process time ΔTH (for example, 40 minutes) has elapsed (yes in S107), 1 is added to the counter i (S108), the defrosting process is completed, and until n times (for example, n = 10). , The freezing step is carried out 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 times (no in S109), the freeze-thaw step is terminated and the set temperature θs is maintained as the maintenance set temperature θR (for example, 0 ° C.) (S110).

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

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

<< 1-3 >> Effect According to the refrigerator 1 according to the first embodiment, the freeze-thaw step including the freezing step of freezing the surface layer portion (surface) of the food and the thawing step of thawing the frozen surface layer portion is repeated. Carry out and then carry out a maintenance process to keep the food temperature constant. This makes it possible to reduce bacteria adhering to the surface layer of the food and improve the preservability of the food. In addition, since the central part of the food is not frozen, the food can be made to last for a long time, and the food can be cut with a kitchen knife or cooked immediately after being taken out, which improves convenience.

<< 1-4 >> Modification Example In the above description, the freezing step is a process of freezing only the surface layer portion of the food and not the central portion, but the freezing step is a process of freezing the central portion of the food, and then the surface layer portion and the process. It is also possible to defrost the center. In this case, it is conceivable to sterilize not only the bacteria existing on the surface layer of the food but also the bacteria existing in the center of the food by going through the freeze-thaw step for the central part of the food.

<< 2 >> Embodiment 2
Hereinafter, the refrigerator 1a according to the second embodiment of the present invention will be described. FIG. 9 is a cross-sectional view showing a schematic configuration of the switching chamber 200a of the refrigerator 1a according to the second embodiment. FIG. 10 is a block diagram showing a schematic configuration of the control system of the refrigerator 1a according to the second embodiment. In FIGS. 9 and 10, the same parts as those in the first embodiment are designated by the same reference numerals, and some description thereof will be omitted.

As shown in FIGS. 9 and 10, in the refrigerator 1a according to the second embodiment, a heater 13 is embedded as a heating mechanism (heating unit) for heating and raising the temperature of the switching chamber 200a below the switching chamber 200a. In that respect, it is different from the refrigerator 1 according to the first embodiment. 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 inside the switching chamber 200a from the thermistor 11, and when the temperature of the switching chamber 200a is equal to or lower than the preset temperature, the control device 8 sets the heater 13 to the heated state.

Further, the control device 8 releases the heater 13 from the heated state when the temperature of the switching chamber 200a becomes equal to or higher than a preset temperature. The control device 8 acquires the temperature of the switching chamber 200a from the thermistor 11, and follows the program stored in the memory 8b in advance so that the temperature inside the switching chamber 200 is maintained at the set temperature. It controls the operating state of the switching chamber damper 12, the heater 13, and the like.

In the above description, the control device 8 is described as controlling the heater 13 in addition to controlling the switching chamber damper 12 and the like in the thawing step, but the control method is not particularly limited to this. 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 the second embodiment, the temperature of the switching chamber 200a can be efficiently raised by installing the heater 13 below the switching chamber 200a. Therefore, the refrigerator 1a can perform the thawing step at a higher speed than the refrigerator according to the first embodiment, and can efficiently perform the freeze-thaw step of the surface layer portion of the food.

<< 3 >> Embodiment 3
Hereinafter, the refrigerator 1b according to the third embodiment of the present invention will be described. FIG. 11 is a cross-sectional view showing a schematic configuration of the switching chamber 200b of the refrigerator 1b according to the third embodiment. FIG. 12 is a block diagram showing a schematic configuration of the control system of the refrigerator 1b according to the third embodiment. In FIGS. 11 and 12, the same parts as those in the first and second embodiments are designated by the same reference numerals, and some description thereof will be omitted.

As shown in FIG. 11, in the refrigerator 1b according to the third embodiment, a cooling plate 14 on which food can be placed is provided on the floor surface of the switching chamber 200b, and a heater 13 and a wind are provided below the cooling plate 14. It differs from the refrigerators 1 and 1a according to the first and second embodiments in that a floor air passage 15 capable of inflowing cold air from the passage 5 is provided. The inflow of cold air 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 from the return air passage (not shown). As shown in FIG. 12, the control device 8 controls the heater 13 and the floor air passage damper 16.

FIG. 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 of the center temperature and the surface temperature of the food stored in the switching chamber 200, and the floor air passage damper 16. It shows the opening / closing and the ON / OFF state of the heater 13. As shown in FIG. 13, the temperature control of the cooling plate 14 of the switching chamber 200b includes a freezing and thawing step including a freezing step (first treatment), a thawing step (second treatment), and a maintenance step (third). Processing) and.

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

One cycle is from the start of the freezing step to the end of the thawing step, and the freezing and thawing step is from repeating this series of temperature control n times preset. The time of one cycle of the freeze-thaw step 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 passage damper 16 is closed and the heater 13 is turned off. In the maintenance step, 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 step, the thawing step, and the maintenance step. Further, different set temperatures may be provided for each of the freezing step, the thawing step, and the maintenance step.

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

In the thawing step, the time t is set to 0 (S306), the floor air passage damper 16 is closed (S307), and the heater 13 is turned on (S308). When the set defrosting process time ΔTH (for example, 30 minutes) has elapsed (yes in S309), 1 is added to the counter i (S310), the defrosting process is completed, and until n times (for example, n = 10) are reached. The freezing step is carried out 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 step is terminated, the floor air passage damper 16 is closed (S312), the heater 13 is turned off (S313), and the process proceeds to the maintenance step.

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 raised in temperature.

<< 4 >> Embodiment 4
Hereinafter, the refrigerator 1c according to the fourth embodiment of the present invention will be described. FIG. 15 is a cross-sectional view showing a schematic configuration of the switching chamber 200c of the refrigerator 1c according to the fourth embodiment. FIG. 16 is a block diagram showing a schematic configuration of the control system of the refrigerator 1c according to the fourth embodiment. The same parts as those in the first to third embodiments are designated by the same reference numerals, and some description thereof will be omitted.

As shown in FIG. 15, in the refrigerator 1c according to the fourth embodiment, a cooling plate 14 on which food can be placed is provided on the floor surface of the switching chamber 200c, and a Pelche element 17 is provided below the cooling plate 14. This is different from the refrigerators 1, 1a and 1b according to the first to third embodiments. Further, the refrigerator 1c according to the fourth embodiment is provided with a drive device (not shown) capable of switching the direction of the current flowing through the Pelche element 17 between the heat dissipation side and the endothermic side. As shown in FIG. 16, the control device 8 is connected to the Pelche 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 of the center temperature and the surface temperature of the food stored in the switching chamber 200, and the state of the Pelche element 17. It is a figure.

As shown in FIG. 17, in the freezing step, the endothermic element 17 is energized on the endothermic side to cool the cooling plate 14. When the freezing step time ΔTL has elapsed (time TL), the freezing step is terminated and the thawing step is started. In the thawing step, the Pelche element 17 is energized on the heat dissipation side to heat the cooling plate 14. When the thawing step time ΔTH has elapsed (time TH), the thawing step is completed. In the maintenance process, the Pelche element 17 is not energized but turned off, 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 inside 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 step, the thawing step, and the maintenance step. Further, different set temperatures may be provided for each of the freezing step, the thawing step, and the maintenance step.

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

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

According to the refrigerator 1c according to the fourth embodiment, the cooling plate 14 and the pelche element 17 are provided on the floor surface of the switching chamber 200c, and the cooling plate 14 is applied to the heat dissipation side and the endothermic side of the pelche element 17. Cool or heat. As a result, the food in the switching chamber 200c can be efficiently frozen or thawed.

<< 5 >> Embodiment 5
Hereinafter, the refrigerator 1d according to the fifth embodiment of the present invention will be described. FIG. 19 is a cross-sectional view showing a schematic configuration of the switching chamber 200d of the refrigerator 1d according to the fifth embodiment. FIG. 20 is a diagram showing a schematic configuration of a refrigerant circuit of the refrigerator 1d according to the fifth embodiment. The same parts as those in the first to fourth embodiments are designated by the same reference numerals, and some description thereof will be omitted.

As shown in FIG. 19, in the refrigerator 1d 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 200d, and a switching chamber control pipe 18 is provided below the cooling plate 14. It differs from the refrigerators 1, 1a, 1b, and 1c according to the first to fourth embodiments in that they are provided. The switching chamber control pipe 18 is provided as a branch from the main circuit 24 that controls the refrigerator 1d, and by switching the three-way valves 19, 25, 26, the cooling plate 14 is cooled by the switching chamber control pipe 18. Or heat it.

As shown in FIG. 20, the refrigerating cycle is composed of 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 tube 27 in this order. And the suction pipe 27 are composed of a main circuit 24 for heat exchange. A bypass circuit 28 branched by the three-way valve 19 and a switching chamber control pipe 18 branched by the three-way valves 25 and 26 and connected to the bypass circuit 28 are provided.

In the freezing step, the main circuit 24 in the order of the compressor 2, the three-way valve 19, the condenser 20, the dryer 21, the capillary tube 22, and the cooler 3 is used, and after leaving the cooler 3, 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 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 step, 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 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 repeating the freezing step and the thawing step 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 as to disconnect the switching chamber control pipe 18. 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 and used.

According to the refrigerator 1d 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 200d, and a switching chamber control pipe 18 is provided below the cooling plate 14. As a result, 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 fan, 5 air passage, 6 operation panel, 7 door, 7a right door, 7b left door, 8 controller, 8a processor, 8b Memory, 10 Door open / close detection switch, 11 Thermista, 12 Switching room damper, 13 Heater, 14 Cooling plate, 15 Floor air passage, 16 Floor air passage damper, 17 Pelche element, 18 Switching room control piping, 19 Three-way valve, 20 condenser, 21 dryer, 22 capillary tube, 23 header, 24 main circuit, 25, 26 three-way valve, 27 suction tube, 28 bypass circuit, 30-hour measuring unit, 90 insulation box, 100 refrigerator compartment, 200, 200a, 200b , 200c, 200d switching room, 300 ice making room, 400 freezer room, 500 vegetable room, 201, 401, 501 storage case.

Claims (10)

A storage room where the object to be cooled is stored, and
A cooling unit having a refrigerating cycle for cooling the storage chamber,
A control unit that controls the cooling unit is provided.
The control unit is attached to the cooling unit.
A freeze-thaw treatment comprising a first treatment of freezing only the surface layer portion of the object to be cooled and a second treatment of thawing only the surface layer portion of the object to be cooled frozen by the first treatment. Repeat it more than once,
The control unit is a refrigerator that controls a set temperature and a set time so as not to freeze a central portion other than the surface layer portion of the object to be cooled in the first process. The control unit is attached to the cooling unit.
The refrigerator according to claim 1, wherein after the completion of the freeze-thaw treatment, a third treatment for maintaining the temperature in the storage chamber at a first temperature higher than the freezing point of the object to be cooled is executed. .. The control unit is attached to the cooling unit.
The refrigerator according to claim 1, wherein after the completion of the freeze-thaw treatment, a fourth treatment for maintaining the temperature in the storage chamber at a second temperature lower than the freezing point of the object to be cooled is executed. .. Further provided with a heating unit for heating the storage chamber,
The control unit
The second treatment is according to any one of claims 1 to 3, wherein the heating unit is controlled so that the temperature in the storage chamber becomes higher than the freezing point of the object to be cooled. The listed refrigerator. The refrigerator according to claim 4, wherein the heating unit includes a heater. The cooling unit is
The refrigerator according to any one of claims 1 to 5, further comprising a Pelche element. The refrigerator according to any one of claims 1 to 6, wherein the cooling unit includes a cooling plate on which the object to be cooled is placed and cooled. The set temperature of the first treatment is in the range of −25 ° C. to −5 ° C.
The refrigerator according to any one of claims 1 to 7, wherein the set temperature of the second treatment is in the range of 0 ° C to 10 ° C. Equipped with a time measurement unit
The control unit has the aspect of claim 1 to 8, wherein the control unit controls the time of one cycle of the freeze-thaw processing within the range of 30 minutes to 90 minutes based on the time measured by the time measurement unit. The refrigerator according to any one of the items. A temperature control method performed by a refrigerator comprising a storage chamber in which the object to be cooled is stored and a cooling unit having a refrigerating cycle for cooling the storage chamber.
The cooling unit is subjected to a first process of freezing only the surface layer portion of the object to be cooled and a second process of thawing only the surface layer portion of the object to be cooled frozen by the first process. It has a step of repeatedly executing the freeze-thaw process including two or more times.
A method for controlling a temperature of a refrigerator, which comprises controlling a set temperature and a set time so as not to freeze a central portion of the object to be cooled other than the surface layer portion in the first process.

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