JP5959703B2 - refrigerator - Google Patents

Description

  The present invention relates to a refrigerator.

  In general, when preserving food, it is desirable to maintain it at the lowest possible temperature and without freezing to maintain the quality. In order to realize such high-quality storage, means for utilizing a supercooled state, which is below the freezing point but does not freeze, has been devised. However, when the storage temperature is 0 ° C. or lower, particularly below the freezing point of food, the supercooled state may be released and ice crystals may be generated. If this state is left after supercooling is released, food freezes and cell damage occurs, resulting in a reduction in food quality.

  In order to avoid such a problem, a method has been proposed in which the temperature is periodically changed to melt ice crystals generated when the supercooled state is released. For example, the technique of Patent Document 1 starts supercooling operation when the operation and stop of the cooling means are repeated one or more times. Therefore, the technique of patent document 1 is the supercooling operation triggered by the time when the operation and the stop of the cooling means by the temperature set value in the normal refrigeration operation are repeated at least once after the operation in the supercooling temperature zone is completed. To start. For this reason, even if there is food that has started to freeze, freezing is reliably prevented by performing the cycle in the normal refrigeration operation even once.

  In addition, the technique of Patent Document 2 considers the difference in the heating rate depending on the load for the purpose of reliably melting the ice crystals generated when the supercooling is released and maintaining the quality of the food. The temperature raising process time is set, and the temperature is controlled by changing the process from the low temperature process to the temperature raising process at a predetermined timing. Thereby, even if the technique of patent document 2 returns to the supercooled state even if the freezing of a foodstuff starts, the supercooled state of a foodstuff is maintained stably.

Japanese Patent No. 4647047 (Claim 1) Japanese Patent No. 4948562 (paragraph [0029])

  However, the technique described in Patent Document 1 starts the supercooling operation when the operation and stop of the cooling means are repeated one or more times, and considers the operation time in the supercooling temperature zone. Absent.

  Moreover, although the technique of patent document 2 considers the operation time in a supercooling temperature zone, the calorie | heat amount balance and the operation time are considered in order to melt | dissolve the generated ice crystal completely. . Therefore, in addition to the latent heat taken away from the water during freezing and the heat given to the ice during the thawing, the latent heat released when changing from water to ice is also considered. Therefore, since the high temperature zone which is the temperature raising process time becomes longer, the average temperature during the storage period of the food is higher as a result.

  The present invention has been made in order to solve the above-described problems, and is a refrigerator capable of preventing the freezing of food from being completed without adversely affecting the food even when the supercooled state is released. Is intended to provide.

  The refrigerator according to the present invention controls the storage room in which the object to be cooled is stored, the cooling means for supplying cold air to the storage room, and the cooling means, and controls the temperature in the storage room during the first time. A first step of lowering to a first temperature lower than the freezing point of the second, and a second step of raising the temperature in the storage chamber to a second temperature higher than the freezing point of the object to be cooled for a second time. And a control device that repeatedly performs the process, and the freezing point and storage while the temperature in the storage chamber is lower than the freezing point of the object to be cooled and the temperature of the object to be cooled is constant at the freezing point. The time integral value of the difference from the room temperature and the temperature and freezing in the storage room while the temperature in the storage room is higher than the freezing point of the object to be cooled and the temperature of the object to be cooled is constant at the freezing point. The time integration value of the difference from the point is the same.

  According to the present invention, the time of the difference between the freezing point and the temperature in the storage chamber while the temperature in the storage chamber is lower than the freezing point of the material to be cooled and the temperature of the cooling object is constant at the freezing point. The integral value and the time integral value of the difference between the temperature in the storage chamber and the freezing point while the temperature in the storage chamber is higher than the freezing point of the cooling object and the temperature of the cooling object is constant at the freezing point Are equal to each other, the food can be returned to the supercooled state without completely melting the ice crystals, and the average temperature during the storage period of the food can be lowered. Therefore, it is possible to prevent the freezing of the food from being completed without adversely affecting the food.

It is a front view which shows the structure of the refrigerator 1 which concerns on Embodiment 1 of this invention. It is a longitudinal cross-sectional view which shows the structure of the refrigerator 1 which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the structure of the refrigerator compartment 100 of the refrigerator 1 which concerns on Embodiment 1 of this invention. It is a functional block diagram of the refrigerator 1 which concerns on Embodiment 1 of this invention. It is a functional block diagram of the control means 1009 which concerns on Embodiment 1 of this invention. It is a graph which shows the time-dependent change of the setting temperature of the low temperature room | chamber 13 and the chamber | room temperature at the time of implementing temperature control in the refrigerator 1 which concerns on Embodiment 1 of this invention. The temperature change in the refrigerator 1 according to Embodiment 1 of the present invention when temperature control is performed, changes over time in the low-temperature chamber 13 and the internal temperature, the amount of heat q1 released from the object to be cooled, and the object to be cooled It is a graph which shows the calorie | heat amount q2. When the low temperature set temperature θL is −3 ° C., the relationship between the time (freezing time) during which the object to be cooled has been frozen after the supercooling is released and the number of fracture peaks when the object is cut is shown. It is a graph. It is a graph which shows the time-dependent change of the preset temperature of the low temperature room | chamber 13 and the temperature in a store | warehouse | chamber when the to-be-cooled object is not cancelled | released supercooling when implementing the temperature control shown in FIG. It is a graph which shows the time-dependent change of the preset temperature of the low temperature room | chamber 13 and the temperature in a store | warehouse | chamber when a to-be-cooled object is cancelled | released supercooling when implementing the temperature control shown in FIG. Changes in the set temperature of the low temperature chamber 13 and the temperature in the refrigerator when the temperature control is performed in the refrigerator 1 in which the low temperature process time ΔTL and the temperature increase process time ΔTH are set so that the heat quantity q1> the heat quantity q2, and the temperature to be cooled It is a graph which shows the calorie | heat amount q1 which a thing discharge | releases, and the calorie | heat amount q2 supplied to a to-be-cooled object. Changes in the set temperature of the low temperature chamber 13 and the temperature in the refrigerator when the temperature control is performed in the refrigerator 1 in which the low temperature process time ΔTL and the temperature increase process time ΔTH are set so that the heat quantity q1 <the heat quantity q2, and the temperature to be cooled It is a graph which shows the calorie | heat amount q1 which a thing discharge | releases, and the calorie | heat amount q2 supplied to a to-be-cooled object. It is a flowchart which shows an example of the process performed with the control apparatus 7 of the refrigerator 1 which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the structure of the refrigerator compartment 100 of the refrigerator 1 which concerns on Embodiment 2 of this invention. It is a functional block diagram of the refrigerator 1 which concerns on Embodiment 2 of this invention.

Embodiment 1 FIG.
(Configuration of refrigerator 1)
FIG. 1 is a front view showing the configuration of the refrigerator 1 according to Embodiment 1 of the present invention. FIG. 2 is a longitudinal sectional view showing the configuration of the refrigerator 1 according to Embodiment 1 of the present invention. 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, vertical relationship etc.) between each structural member in a specification is a thing when installing the refrigerator 1 in the state which can be used in principle.

  The refrigerator 1 maintains the quality of the food by maintaining the food in a supercooled state by periodically changing the temperature. As will be described later, for example, in consideration of the calorific value balance, The time for each process is determined.

  As shown in FIG. 2, the refrigerator 1 in FIG. 1 has 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.

  The refrigerator 1 of the present example includes a refrigerating room 100 disposed at the top as a plurality of storage rooms, a switching room 200 disposed below the refrigerating room 100, and a switching room adjacent to the side of the switching room 200. 200, an ice making chamber 300 arranged in parallel with 200, a freezing chamber 400 arranged below the switching chamber 200 and the ice making chamber 300, and a bottom vegetable room 500 arranged below the freezing chamber 400. Yes.

  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.

  The opening formed in the front surface of the refrigerator compartment 100 is provided with a rotary door 8 that opens and closes the opening. The door 8 of this example is a double door type (double door type), and is constituted by a right door 8a and a left door 8b. An operation panel 6 is provided on the outer surface of the door 8 (for example, the left door 8b) serving as the front surface of the refrigerator 1. The operation panel 6 includes an operation switch (operation unit 1003 shown in FIG. 4) for adjusting settings such as the cold insulation temperature of each storage room, and a liquid crystal display unit that displays the temperature of each storage room, inventory information in the warehouse, and the like. (Display unit 1001 shown in FIG. 4). The operation panel 6 may include a touch panel that serves as both the operation unit 1003 and the display unit 1001. The configuration in the refrigerator compartment 100 will be described later.

  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. In the vegetable compartment 500, a storage case 501 capable of storing food and the like is stored in a freely retractable manner. The storage case 501 is supported by a door frame, and slides in the front-rear direction in conjunction with opening and closing of the door. 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.

(Cooling mechanism)
On the back side of the refrigerator 1, a compressor 2, a cooler 3 (evaporator), a blower fan 4, and an air passage 5 are provided as a cooling mechanism for cooling each storage chamber. The compressor 2 and the cooler 3 constitute a refrigeration cycle together with a condenser and an expansion device (not shown). The cold air produced by the compressor 2 and the cooler 3 is blown by the blower fan 4 and supplied to the freezing room 400, the switching room 200, the ice making room 300, and the refrigerating room 100 through the air passage 5 on the back surface of the refrigerator 1. The Returned cold air from the refrigerator compartment 100 is supplied to the vegetable compartment 500 via a refrigerator air return passage (not shown). The cold air supplied to the vegetable compartment 500 is returned to the cooler 3 through a vegetable room return air passage (not shown). The temperature of each storage room is detected by a thermistor (not shown) installed in each storage room, and the degree of opening of a damper (not shown) installed in the air passage 5 is set to a preset temperature. It is controlled by adjusting the output of the compressor 2 and the amount of air blown by the blower fan 4.

  The control device 7 is a microcomputer including a CPU, a memory, an input / output unit, a timer, and the like, and controls operations of the compressor 2, the blower fan 4, a damper, and the like of the refrigerator 1. The memory stores an operation program of the refrigerator 1 and the like.

(Configuration of the refrigerator compartment 100)
FIG. 3 is a cross-sectional view showing the configuration of the refrigerator compartment 100 of the refrigerator 1 according to Embodiment 1 of the present invention. As shown in FIG. 3, the refrigerating room 100 includes a door open / close detection switch 9 that detects the open / closed state of the door 8, one or a plurality of door pockets 10 provided inside the door 8, and the inside of the refrigerating room 100. And one or a plurality of shelves 11 that partition the space into a plurality of spaces. A part of the lower part in the refrigerator compartment 100 includes an upper stage portion including a chilled chamber 12 maintained at 0 ° C. or higher, and a lower stage portion including a low temperature chamber 13 that stores food without freezing at a temperature below the freezing point. It has an upper and lower two-stage configuration.

  The air passage 5 on the back side of the refrigerator compartment 100 is divided into an air passage 5 a that sends cool air to the refrigerator compartment 100 and the chilled compartment 12 and an air passage 5 b that sends cool air to the low temperature chamber 13. The air passage 5a is provided with a refrigerator compartment damper 16, and the air passage 5b is provided with a low temperature compartment damper 17. A refrigerator compartment thermistor 14 is provided on the back of the refrigerator compartment 100, and a cryogenic chamber thermistor 15 is provided on the back of the cryogenic compartment 13. The temperature of the refrigerator compartment 100 is detected by the refrigerator compartment thermistor 14 and is controlled by adjusting the opening degree of the refrigerator compartment damper 16. The temperature of the low temperature greenhouse 13 is detected by the low temperature chamber thermistor 15 and controlled by adjusting the opening degree of the low temperature chamber damper 17.

(Function block of refrigerator 1)
FIG. 4 is a functional block diagram of the refrigerator 1 according to Embodiment 1 of the present invention. The same code | symbol is attached | subjected to the structure same as the component shown in FIGS. 1-3. As shown in FIG. 4, the control device 7 includes, for example, a control unit 1009 and a storage unit 1005. The functional configuration of the control unit 1009 is constructed by executing a program on hardware such as a microcomputer. The storage unit 1005 is the memory described above, and is constructed of, for example, a semiconductor element.

  The control device 7 acquires the temperatures of the refrigerator compartment 100 and the cryogenic chamber 13 from the refrigerator compartment thermistor 14 and the cryogenic chamber thermistor 15, respectively. The control device 7 controls the cooling unit 1007 and the like according to an operation program stored in advance in the storage unit 1005 so that the inside of the refrigerator compartment 100 and the low temperature chamber 13 are maintained at the set temperatures. The cooling unit 1007 includes, for example, the compressor 2, the blower fan 4, the refrigerator compartment damper 16, and the low temperature compartment damper 17. Further, the control device 7 inputs an operation signal from the operation unit 1003 of the operation panel 6 and outputs a display signal to the display unit 1001 of the operation panel 6. The control device 7 also receives a detection signal from the door opening / closing detection switch 9.

(Function block of control device 7)
FIG. 5 is a functional block diagram of the control means 1009 according to Embodiment 1 of the present invention. FIG. 6 is a graph showing changes over time in the set temperature of the low temperature chamber 13 and the internal temperature when the temperature control is performed in the refrigerator 1 according to Embodiment 1 of the present invention.

  As shown in FIG. 5, the control unit 1009 includes a first processing unit 1101, a second processing unit 1103, and a time measuring unit 1105. By repeating a cycle having a low temperature process time and a temperature increase process time, The control of the set temperature in the process and the control of the set temperature in the temperature raising process are repeated. As will be described in detail later, the low temperature step includes an introduction step and a low temperature maintenance step.

  The first processing means 1101 in FIG. 5 generates a control command based on the low temperature process time, the introduction process time, the low temperature maintenance process time, the set temperature, and the low temperature set temperature. The second processing unit 1103 in FIG. 5 generates a control command based on the temperature raising process time, the set temperature, and the temperature raised set temperature. 5 measures time used by the first processing unit 1101 and the second processing unit 1103, for example, a low temperature process time, an introduction process time, a low temperature maintenance process time, and a temperature increase process time. . The first processing unit 1101 includes an introduction unit 1201 and a maintenance unit 1203. The introduction unit 1201 generates a control command in the introduction process among the low temperature processes based on the introduction process time, the set temperature, and the low temperature set temperature. The maintenance unit 1203 generates a control command in the low temperature maintenance process among the low temperature processes based on the low temperature maintenance process time, the set temperature, and the low temperature set temperature.

(Temperature control)
For example, as shown in FIG. 6, one period includes the low temperature process and the temperature raising process described above. In other words, the temperature control of the low temperature chamber 13 sets the set temperature to the low temperature set temperature or the temperature set temperature for each cycle including the first step (for example, the low temperature step) and the second step (for example, the temperature increase step). This controls the internal temperature. Thereby, the internal temperature of the low temperature chamber 13 is periodically changed. The control means 1009 starts the cooling means 1007 such as the compressor 2, the blower fan 4, the low temperature chamber damper 17, etc. so that the temperature raising process is started when the low temperature process is finished and the temperature lowering process is started when the temperature raising process is finished. Control.

  The set temperature of the low greenhouse 13 is changed in each of the low temperature process and the temperature raising process. In the low temperature process, the set temperature is set to the low temperature set temperature. The low temperature setting temperature is a temperature lower than the freezing point of an object to be cooled such as food. In the temperature raising step, the set temperature is set to the temperature rise set temperature. The temperature rise set temperature is a temperature higher than the freezing point of an object to be cooled such as food.

  The low temperature set temperature is θL, the temperature rise set temperature is θH, and θH> θL. The low temperature process time is ΔTL, and the temperature raising process time is ΔTH. When the introduction unit 1201 of the first processing unit 1101 in FIG. 5 starts the low temperature process, as shown in FIG. 6, the introduction unit 1201 starts the introduction process and lowers the set temperature step by step for each preset time. 13 is cooled, and when the set temperature reaches the low temperature set temperature θL by the time TL1, the process proceeds to the low temperature maintenance step. As shown in FIG. 6, the maintaining means 1203 of the first processing means 1101 in FIG. 5 performs the low temperature process until the time TL is reached, that is, when the low temperature process time ΔTL has elapsed from the start of the low temperature process. The process ends and the process proceeds to the temperature raising process.

  As shown in FIG. 6, the second processing means 1103 in FIG. 5 switches the set temperature of the low temperature chamber 13 to the set temperature setting temperature θH in the temperature increasing process, and increases the set temperature for the temperature increasing process time ΔTH. The set temperature is maintained at θH. As shown in FIG. 6, the second processing means 1103 in FIG. 5 ends the temperature raising process when the time TH is reached and the temperature raising process time ΔTH has elapsed. That is, as shown in FIG. 6, the period from the start of the low temperature process to the end of the temperature raising process is one cycle, and the first processing means 1101 and the second processing means 1103 in FIG. This series of temperature control is repeated while measuring the time.

  Next, the low temperature process time ΔTL and the temperature raising process time ΔTH will be specifically described. FIG. 7 shows changes over time in the set temperature and the internal temperature of the low temperature chamber 13 when the temperature control is performed in the refrigerator 1 according to Embodiment 1 of the present invention, the amount of heat q1 released from the object to be cooled, and the object to be cooled. It is a graph which shows calorie | heat amount q2 supplied to a thing.

  As shown in FIG. 7, in the low temperature process, the time when the internal temperature θ (T) reaches the freezing point θf of the object to be cooled such as food is Tf1. In the temperature raising step, the time when the internal temperature θ (T) reaches the freezing point θf of the object to be cooled such as food is defined as Tf2. In the low-temperature process in the next cycle, the time when the internal temperature θ (T) reaches the freezing point θf of the object to be cooled such as food is Tf3. Further, the time from the start of the temperature raising process until the internal temperature θ (T) reaches the freezing point θf of the object to be cooled such as food is assumed to be ΔTf2. Further, the time from when the low temperature process of the next cycle is started until the inside temperature θ (T) reaches the freezing point θf of the object to be cooled such as food is assumed to be ΔTf1.

  The amount of heat released by the object to be cooled whose temperature is constant at the freezing point θf during the time ΔT1 when the internal temperature θ (T) is lower than the freezing point θf, that is, during Tf2−Tf1, is q1. To do. Further, during the time ΔT2 when the internal temperature θ (T) is higher than the freezing point θf, that is, during Tf3-Tf2, the amount of heat supplied to the object to be cooled whose temperature is constant at the freezing point θf. Is q2. The amount of heat q1 corresponds to the hatched portion between θf between Tf1 and Tf2 and the internal temperature θ (T) in the area of the hatched portion in FIG. 7, and is expressed as the following equation (1). Is done. The amount of heat q2 corresponds to the shaded portion between θf between Tf2 and Tf3 and the internal temperature θ (T) in the area of the shaded portion in FIG. 7, and is expressed as the following equation (2). Is done.

  The low temperature process time ΔTL and the temperature raising process time ΔTH are determined so that the relationship between the heat quantity q1 and the heat quantity q2 satisfies q1 = q2. That is, the low temperature process time ΔTL and the temperature increase process time ΔTH are obtained and set so that the heat quantity q1 as the first heat quantity and the heat quantity q2 as the second heat quantity are balanced.

  Next, the low temperature process time ΔTL and the temperature raising process time ΔTH will be described more specifically. The low temperature process time ΔTL is arbitrarily set under conditions set by simple experiments, whereas the temperature increase process time ΔTH is determined so as to satisfy the expressions (1) and (2). Is.

  First, the cooling rate in the introduction step is set to a condition that allows an object to be cooled such as food to enter a supercooled state. For example, when the low temperature setting temperature θL is −3 ° C. and the cooling time per 1 ° C. is 35 minutes or more, it is an experiment that an object to be cooled such as food enters a supercooled state with a very high probability. I know.

  Therefore, when the cooling rate of the introduction process is arbitrarily set so as to satisfy such a condition, as shown in FIG. 7, after the low temperature process is started, that is, the freezing point is started after the introduction process is started. The time ΔTf1 until reaching θf and the time TL1 until the introduction process is finished are determined. Further, the low temperature process time ΔTL needs to be set so that time TL1 <time TL. Furthermore, as will be described later with reference to FIG. 8, the low temperature process time ΔTL needs to be set within a time before freezing is recognized, as is apparent from a simple experiment. For example, when the low temperature set temperature θL is −3 ° C., the low temperature process time ΔTL is set to 8 hours or less.

  Here, the reason why the low temperature process time ΔTL is set within the time before the freezing is recognized will be described. FIG. 8 illustrates the time (freezing time) during which the object to be cooled is frozen after the supercooling is released when the low temperature set temperature θL is −3 ° C., and the number of fracture peaks when the object to be cooled is cut. It is a graph which shows the relationship.

  If the formation and growth of ice crystals in the food after the supercooling is released, the tactile sensation of the food will change. Changes in how people perceive that food is frozen include the hardness when touched and the sensation of breaking ice particles when cut. However, several hours after the release of the supercooling, it was found from experiments that the tactile sensation of the food hardly changes because the ice crystals are fine and minute.

  Furthermore, it is possible to maintain substantially the same state as the non-frozen state by returning to the state immediately after the release of supercooling or within several hours without melting all the generated ice crystals. I understood. The number of rupture peaks in FIG. 8 is the number of local maximum points in the time-varying waveform of the cutting load from the start of cutting to the end of cutting, and represents a feeling of smashing of ice particles. FIG. 8 shows the number of break peaks corresponding to the freezing time, and the deviation is also shown on the graph. From the results of FIG. 8, it was found that the boundary between the non-frozen state (freezing time 0 hour) and the frozen state is at the freezing time 8 hours. Therefore, it is desirable to set the low temperature process time ΔTL to 8 hours or less in order to melt the ice crystals before the freezing is started or the state where the freezing is recognized.

  That is, if the low temperature process time ΔTL is set within the allowable freezing time, which is the time from the non-frozen state to the frozen state, as in the above 8 hours, The amount of heat for reliably melting the generated ice crystals is not necessary, and it is sufficient that the amount of heat is balanced between the low temperature step and the temperature raising step so that freezing does not proceed any further. That is, if the low temperature process time ΔTL is set within the allowable freezing time, the heat quantity q1 and the heat quantity q2 need to be balanced, so the temperature rise process time ΔTH is the same as in the prior art. It will be shorter than if it is surely melted. Note that the above 8 hours is an example and varies depending on the aircraft.

  Next, returning to FIG. 7, a description will be given of obtaining the temperature raising process time ΔTH from the low temperature process time ΔTL. First, the time ΔTf from the start of the temperature raising process until the internal temperature θ (T) reaches the freezing point θf can be obtained from the temperature raising rate. The rate of temperature increase will become clear from experiments. Next, the calorie | heat amount q1 represented by Formula (1) is represented by an approximation formula like the following formula | equation (3) from the shaded area of FIG. Further, the amount of heat q2 represented by the equation (2) is represented by an approximate equation as in the following equation (4) from the shaded area in FIG. From Equations (3) and (4), the temperature raising process time ΔTH is determined so as to satisfy the heat quantity q1 = q2, and the time TH is set.

  In other words, the low temperature process time ΔTL is obtained based on the allowable freezing time, the heat quantity q1, and the heat quantity q2, and the temperature raising process time ΔTH is the low temperature process time ΔTL, the heat quantity q1, and the heat quantity q2. It is obtained based on. The low temperature process time ΔTL and the temperature raising process time ΔTH are set so that the heat quantity q1 and the heat quantity q2 are in a balanced state.

  That is, the low temperature process time ΔTL and the temperature increase process time ΔTH are obtained based on a state where the heat quantity q1 and the heat quantity q2 are balanced under the constraint that the low temperature process time ΔTL is equal to or shorter than the allowable freezing time. It is.

  Next, various temperature control is illustrated. FIG. 9 is a graph showing changes over time in the set temperature and the internal temperature of the low temperature chamber 13 when the object to be cooled is not released from supercooling when the temperature control shown in FIGS. 6 and 7 is performed. When the object to be cooled such as food does not release the supercooling, the time is delayed from the time-dependent change in the internal temperature of the low temperature chamber 13, but the temperature of the object to be cooled such as food depends on the heat capacity. Thus, the temperature continuously changes from the low temperature set temperature θL to the temperature rise set temperature θH.

  FIG. 10 is a graph showing changes over time in the set temperature of the low temperature chamber 13 and the internal temperature when the object to be cooled is released from supercooling when the temperature control shown in FIGS. 6 and 7 is performed. In the low-temperature process, an object to be cooled such as food in the low-temperature chamber 13 is in a supercooled state in which it is not frozen even at a freezing point θf or less, but the supercooled state is not energy efficient. It is in a stable state. Therefore, for example, when a sudden temperature change occurs in the low temperature chamber 13 due to an impact such as opening / closing of the door 8 or some factor, the supercooling state may be released. When the supercooled state of the object to be cooled such as food is released, fine ice crystals begin to be generated almost uniformly inside the object to be cooled such as food and freezing is started.

  Therefore, the temperature is raised to a high temperature range at a predetermined timing or like a temperature raising process in which the start of freezing of an object to be cooled such as food is detected and the set temperature is set to the temperature rise set temperature θH. By doing so, it is possible to avoid the progress and completion of freezing, and to prevent damage to tissues or cells of an object to be cooled such as food by ice crystals. After the temperature rise control to the high temperature zone, at a predetermined timing, it is cooled again like a food by returning to the low temperature zone again like the low temperature process to set the set temperature to the low temperature set temperature θL. It is possible to suppress the quality deterioration of the product.

  FIG. 10 shows that supercooling is released, fine ice crystals are formed, and freezing is started at time Tf when the temperature of an object to be cooled such as food becomes equal to or lower than the freezing point θf. Next, at time TL, by switching the set temperature of the low temperature chamber 13 to the temperature rise set temperature θH, melting of fine ice crystals inside the object to be cooled such as food is started, and the time TH at which the temperature rise process ends. However, the object to be cooled, such as food, has returned to a state equivalent to the non-frozen state. In a period subsequent to the period in which the supercooled state has occurred, the object to be cooled such as food enters the supercooled state at time Tf1 when the temperature of the object to be cooled such as food becomes equal to or lower than the freezing point θf. Freezing has started, and the phase has changed.

  At this time, since the low temperature process time ΔTL and the temperature raising process time ΔTH are set so as to satisfy the heat quantity q1 = q2, the heat quantity q1 for proceeding with freezing is equal to the heat quantity q2 for melting the ice crystals. The low temperature process time ΔTL is set to be equal to or less than the allowable freezing time. Therefore, the refrigerator 1 is in a state equivalent to the state immediately after releasing the supercooling, that is, the time Tf1 and immediately after the start of freezing, that is, the time Tf1, at time TH_2 at the time when the temperature raising process is finished. Can be restored.

  FIG. 11 shows changes over time in the set temperature and the internal temperature of the low temperature chamber 13 when temperature control is performed in the refrigerator 1 in which the low temperature process time ΔTL and the temperature increase process time ΔTH are set so that the heat quantity q1> the heat quantity q2. And a quantity of heat q1 released from the object to be cooled and a quantity of heat q2 supplied to the object to be cooled.

  At this time, ice crystals generated in a supercooled state gradually grow and freeze, and eventually freeze is completed. At time Tf when the temperature of the object to be cooled, such as food, becomes equal to or lower than the freezing point θf, the object to be cooled is released from the supercooling, fine ice crystals are generated, and freezing is started. Next, at time TL, the set temperature of the low temperature chamber 13 is switched to the temperature rise set temperature θH, and melting of fine ice crystals in the object to be cooled is started. When the time from the time Tf to the time TL is short, the object to be cooled has returned to a state equivalent to the non-frozen state at the time TH when the temperature raising step is completed.

  In the period following the period in which the supercooling release occurs, at time Tf1 when the temperature of the non-cooled object becomes equal to or lower than the freezing point θf, the object to be cooled starts freezing without entering the supercooled state, and enters the phase change state. It has become. At this time, since the low temperature process time ΔTL and the temperature rising process time ΔTH are calorie q1> q2, the calorie q1 for proceeding freezing is smaller than the calorie q2 for melting the ice crystal, and the freezing proceeds and freezing is performed. It cannot be avoided to complete. That is, under the condition that the amount of heat q1> q2, it is difficult to return the object to be cooled that has been released from supercooling to the supercooled state again.

  FIG. 12 shows changes over time in the set temperature and the internal temperature of the low temperature chamber 13 when temperature control is performed in the refrigerator 1 in which the low temperature process time ΔTL and the temperature increase process time ΔTH are set so that the heat quantity q1 <heat quantity q2. And a quantity of heat q1 released from the object to be cooled and a quantity of heat q2 supplied to the object to be cooled.

  FIG. 12 shows a case where the low temperature process time ΔTL and the temperature increase process time ΔTH are set so that q0 + q1 ≦ q2 in consideration of the amount of heat q0 released by the object to be cooled such as food when releasing the supercooling. Is illustrated. In this case, the object is to melt all the ice crystals generated when the object to be cooled is released from the supercooling and restore it until it is completely unfrozen. For this reason, since it is possible to always enter the supercooled state even in the next cycle, the amount of heat q1 becomes the amount of heat released by the non-cooled material whose temperature is constant at the freezing point θf during the low temperature maintaining step. .

  At this time, since the temperature raising process time ΔTH becomes long, the time average temperature of the non-cooled material inevitably increases. Therefore, in order to avoid the completion of freezing and maintain the preservation quality of food at a low temperature, while setting the low temperature process time ΔTL and the temperature increase process time ΔTH so that q1 = q2 and q2 <q0 + q1 The low temperature process time ΔTL is preferably set to be equal to or less than the allowable freezing time. The amount of heat q1 = q2 is not strictly required, and q1 <q2 may be satisfied if q2 <q0 + q1 is satisfied.

(Processing example of refrigerator 1)
FIG. 13 is a flowchart illustrating an example of processing executed by the control device 7 of the refrigerator 1 according to Embodiment 1 of the present invention. First, when the refrigerator 1 is turned on or selected by the operation panel 6, temperature control is started, and the cold room thermistor 15 detects the internal temperature θ of the cold room 13.

(Step S101)
When the internal temperature θ is equal to or higher than the temperature rise set temperature θH (for example, 1 ° C.), the control device 7 proceeds to step S102. On the other hand, when the internal temperature θ is lower than the temperature rise set temperature θH, the control device 7 proceeds to step S112.

(Step S102)
The control device 7 sets the timer T = 0 and starts the low temperature process.

  The first small process of the low temperature process is an introduction process. In the introduction step, n-stage control (for example, n = 12) is performed in which the set temperature is lowered and cooled every preset time. That is, the control device 7 gradually decreases the set temperature until the low temperature set temperature θL is reached during the introduction process time.

(Step S103)
The control device 7 sets the set temperature θs = θH−Δθ.

(Step S104)
The control device 7 sets i = 0.

(Step S105)
The control device 7 sets the timer T = 0.

  That is, the control device 7 sets the set temperature θs of the low temperature chamber 13 to a temperature lower by Δθ (for example, 0.3 ° C.) than the temperature rise set temperature θH, and sets the counter i = 0 and the timer T = 0.

(Step S106)
The control device 7 determines whether or not time t = ΔT. If the time t = ΔT, the control device 7 proceeds to step S107. On the other hand, if the time t is not equal to ΔT, the control device 7 returns to step S106.

(Step S107)
The control device 7 sets the set temperature θs = θs−Δθ.

(Step S108)
The control device 7 sets i = i + 1.

(Step S109)
The control device 7 determines whether i ≧ n. If i ≧ n, the control device 7 proceeds to step S110. On the other hand, if not i ≧ n, the control device 7 returns to step S105.

  That is, when a preset time ΔT (for example, 20 minutes) elapses, the control device 7 lowers the set temperature θs by Δθ, adds 1 to the counter i, and continues until the above reaches n stages (for example, n = 10). Repeat the operation.

(Step S110)
The control device 7 sets the set temperature θs = θL. That is, when the introduction process is completed, the control device 7 sets the set temperature θs to the low temperature set temperature θL (for example, −3 ° C.), and starts the low temperature maintenance process that is the second small process of the low temperature process.

(Step S111)
The control device 7 determines whether or not time T = ΔTL. If the time T = ΔTL, the control device 7 proceeds to step S112. On the other hand, if the time T is not equal to ΔTL, the control device 7 returns to step S111. That is, when the low temperature process time ΔTL (for example, 300 minutes) in which the time T is set in advance has elapsed from the start of the low temperature process, the control device 7 ends the low temperature maintenance process and transitions to the temperature increase process.

(Step S112)
The control device 7 sets the timer T = 0.

(Step S113)
The control device 7 sets the set temperature θs = θH.

  That is, the control device 7 resets the timer T and switches the set temperature θs of the low temperature chamber 13 to the temperature increase set temperature θH in the temperature increase process, and starts the temperature increase process.

(Step S114)
The control device 7 determines whether or not time T = ΔTH. If the time T = ΔTH, the control device 7 returns to step S102. On the other hand, if the time T is not equal to ΔTH, the control device 7 returns to step S114.

  That is, when the set temperature rising process time ΔTH (for example, 240 minutes) has elapsed, the control device 7 performs the repetitive control so as to end the temperature rising process and return to the low temperature process again.

  In the temperature raising step, the low temperature chamber damper 17 may be closed to stop the state in which the cold air flows into the low temperature chamber 13 and raise the internal temperature of the low temperature chamber 13. Further, in the temperature raising step, even if the internal temperature of the low temperature chamber 13 is increased by operating the blower fan 4 when the compressor 2 is stopped and opening the low temperature chamber damper 17 to circulate the air in the refrigerator 1. Good. In addition, an air passage that communicates between the refrigerator compartment 100 or the vegetable compartment 500 and the low temperature compartment 13 and a damper that controls the flow of air between the refrigerator compartment 100 or the vegetable compartment 500 and the low temperature compartment 13 are provided in the air passage, When the temperature of the low greenhouse 13 is raised, the damper may be opened, and air having a temperature higher than that of the cold room 13 may be caused to flow into the cold room 13 from the refrigerator room 100 or the vegetable room 500.

(Effect of refrigerator 1)
As described above, in the first embodiment, the refrigerator 1 performs control to periodically change the temperature within a predetermined allowable freezing time in a state where the time of each process is set in consideration of the heat balance. Specifically, the low-temperature process time is set within an allowable freezing time, and the heat-up process time is set so that the amount of heat q1 for proceeding freezing and the amount of heat q2 for melting ice crystals are balanced. Yes. As a result, the object to be cooled such as food can be returned to the supercooled state without melting the ice crystals completely, and the average temperature during the storage period of the object to be cooled can be lowered. Therefore, the refrigerator 1 can prevent the object to be cooled from being completely frozen without adversely affecting the object to be cooled.

Embodiment 2. FIG.
(Configuration of refrigerator 1)
A refrigerator 1 according to Embodiment 2 of the present invention will be described. FIG. 14 is a cross-sectional view showing the configuration of the refrigerator compartment 100 of the refrigerator 1 according to Embodiment 2 of the present invention. FIG. 15 is a functional block diagram of the refrigerator 1 according to Embodiment 2 of the present invention.

  As shown in FIGS. 14 and 15, a heater 18 is embedded below the low temperature chamber 13 (floor surface of the refrigerator compartment 100) as a heating mechanism (heating means) for heating the low temperature chamber 13 to raise the temperature. Yes. By installing the heater 18 below the low temperature chamber 13, the temperature of the low temperature chamber 13 can be increased efficiently. The control device 7 acquires the temperature in the low temperature chamber 13 from the low temperature chamber thermistor 15, and sets the heater 18 to a heated state when the temperature of the low temperature chamber 13 is equal to or lower than a preset temperature. Moreover, the control apparatus 7 cancels | releases the heater 18 from a heating state, when the temperature of the low temperature chamber 13 becomes more than the preset temperature. The control device 7 acquires the temperature of the low temperature chamber 13 from the low temperature chamber thermistor 15, and the compressor 2, the air blower according to the program stored in the storage unit 1005 in advance so that the inside of the low temperature chamber 13 is maintained at the set temperature. The operating state of the fan 4, the low temperature chamber damper 17, the heater 18, etc. is controlled.

  In the above description, the control device 7 has been described as controlling the heater 18 in addition to the control of the low temperature chamber damper 17 and the like in the temperature raising step, but is not particularly limited thereto. For example, the controller 7 may raise the temperature of the low temperature chamber 13 by controlling the heater 18 without controlling the low temperature chamber damper 17 or the like in the temperature raising step.

(Effect of refrigerator 1)
As described above, in the second embodiment, the refrigerator 1 can perform the temperature rise control in the temperature raising step using the heater 18. Therefore, the refrigerator 1 can raise the temperature of the low temperature chamber 13 efficiently.

  As described above, the refrigerator 1 according to the embodiment includes the storage room for storing the object to be cooled, the cooling means 1007 for cooling the storage room, and the control means 1009 for controlling the cooling means 1007. The cooling means 1007 is controlled to have the first step and the second step, and the second step is started at the end of the first step. In the first step, the set temperature in the storage chamber is cooled. The low temperature set temperature θL lower than the freezing point of the object is set, and in the second step, the set temperature in the storage chamber is set to the temperature rise set temperature θH higher than the freezing point of the object to be cooled, and the first step and the second step The process time is such that the temperature in the storage chamber is lower than the allowable freezing time, which is the time from the non-frozen state to the frozen state, of the first step. The object to be cooled is discharged while it is below the freezing point. The amount of heat q1 to be obtained and the amount of heat q2 supplied to the object to be cooled while the temperature in the storage chamber is higher than the freezing point of the object to be cooled are obtained based on a balanced state.

  In the first and second embodiments, the object to be cooled may be collected from the natural world, such as raw meat of small animals that are not for food as well as food. Alternatively, raw animal meat for experiments may be used. That is, what is necessary is just to preserve | save in a supercooled state.

  DESCRIPTION OF SYMBOLS 1 Refrigerator, 2 Compressor, 3 Cooler, 4 Blower, 5, 5a, 5b Air passage, 6 Operation panel, 7 Control device, 8 Door, 8a Right door, 8b Left door, 9 Door open / close detection switch, 10 Door Pocket, 11 Shelf, 12 Chilled room, 13 Low greenhouse, 14 Cold room thermistor, 15 Low greenhouse thermistor, 16 Cold room damper, 17 Low greenhouse damper, 18 Heater, 90 Heat insulation box, 100 Cold room, 200 Switching room, 201 , 401, 501 Storage case, 300 Ice making room, 400 Freezing room, 500 Vegetable room, 1001 Display unit, 1003 Operation unit, 1005 Storage unit, 1007 Cooling unit, 1009 Control unit, 1101 First processing unit, 1103 Second processing unit 1105 Timekeeping means, 1201 Introduction means, 1203 Maintenance means.

Claims (11)

A storage room for storing the object to be cooled;
Cooling means for supplying cold air into the storage chamber;
Controlling the cooling means to reduce the temperature in the storage chamber to a first temperature lower than the freezing point of the object to be cooled for a first time; and for a second time, A controller for repeatedly performing the second step of raising the temperature in the storage chamber to a second temperature higher than the freezing point of the object to be cooled, and
Time integration of the difference between the freezing point and the temperature in the storage chamber while the temperature in the storage chamber is lower than the freezing point of the material to be cooled and the temperature of the cooling object is constant at the freezing point And the difference between the temperature in the storage chamber and the freezing point while the temperature in the storage chamber is higher than the freezing point of the object to be cooled and the temperature of the cooling object is constant at the freezing point. Refrigerator with the same time integral value. A storage room for storing the object to be cooled;
Cooling means for supplying cold air into the storage chamber;
Controlling the cooling means to reduce the temperature in the storage chamber to a first temperature lower than the freezing point of the object to be cooled for a first time; and for a second time, A controller for repeatedly performing the second step of raising the temperature in the storage chamber to a second temperature higher than the freezing point of the object to be cooled, and
In the second time, the temperature in the storage chamber is lower than the freezing point of the object to be cooled and the temperature of the object to be cooled is constant at the freezing point. A temperature integrated value of the difference between the temperature and the temperature in the storage chamber while the temperature in the storage chamber is higher than the freezing point of the object to be cooled and the temperature of the object to be cooled is constant at the freezing point. And a refrigerator in which the time integral value of the difference between the freezing point and the freezing point is equal. A storage room for storing the object to be cooled;
Cooling means for supplying cold air into the storage chamber;
Controlling the cooling means to reduce the temperature in the storage chamber to a first temperature lower than the freezing point of the object to be cooled for a first time; and for a second time, A controller for repeatedly performing the second step of raising the temperature in the storage chamber to a second temperature higher than the freezing point of the object to be cooled, and
While the temperature in the storage chamber is lower than the freezing point of the object to be cooled and the temperature of the object to be cooled is constant at the freezing point, the temperature in the storage chamber is the temperature of the object to be cooled. Higher than the freezing point and lower than the second heat amount while the temperature of the object to be cooled is constant at the freezing point, and the second heat amount is equal to the first heat amount and the third heat amount. Less than the total amount of heat,
The first amount of heat is obtained when the temperature in the storage chamber is lower than the freezing point of the object to be cooled and the temperature of the object to be cooled is constant at the freezing point. It is the time integral value of the difference from temperature,
The second amount of heat is equal to the temperature in the storage chamber and the freezing while the temperature in the storage chamber is higher than the freezing point of the object to be cooled and the temperature of the object to be cooled is constant at the freezing point. Is the time integral of the difference from the point,
The third heat quantity is a refrigerator in which the object to be cooled is released when the supercooling is released. A storage room for storing the object to be cooled;
Cooling means for supplying cold air into the storage chamber;
Controlling the cooling means to reduce the temperature in the storage chamber to a first temperature lower than the freezing point of the object to be cooled for a first time; and for a second time, A controller for repeatedly performing the second step of raising the temperature in the storage chamber to a second temperature higher than the freezing point of the object to be cooled, and
During the second time, the first amount of heat while the temperature in the storage chamber is lower than the freezing point of the object to be cooled and the temperature of the cooling object is constant at the freezing point is The temperature of the object to be cooled is higher than the freezing point of the object to be cooled and the temperature of the object to be cooled is less than the second amount of heat while the temperature is constant at the freezing point, and the second amount of heat is the second amount of heat. Is a time that is less than the total value of the heat quantity of 1 and the third heat quantity,
The first amount of heat is obtained when the temperature in the storage chamber is lower than the freezing point of the object to be cooled and the temperature of the object to be cooled is constant at the freezing point. It is the time integral value of the difference from temperature,
The second amount of heat is equal to the temperature in the storage chamber and the freezing while the temperature in the storage chamber is higher than the freezing point of the object to be cooled and the temperature of the object to be cooled is constant at the freezing point. Is the time integral of the difference from the point,
The third heat quantity is a refrigerator in which the object to be cooled is released when the supercooling is released.   The refrigerator according to any one of claims 1 to 4, wherein the first time is a time equal to or shorter than an allowable freezing time until the object to be cooled is recognized to be frozen.   The refrigerator according to claim 5, wherein the permissible freezing time is predetermined according to the first temperature.   The refrigerator according to claim 6, wherein the allowable freezing time is 8 hours when the first temperature is set to -3 ° C.   The refrigerator according to any one of claims 5 to 7, wherein the permissible freezing time is a time when the number of fracture peaks when the object to be cooled is cut is larger than that at the start of freezing. The first step includes
An introduction step of stepwise reducing the set temperature in the storage chamber until reaching the first temperature;
The refrigerator as described in any one of Claims 1-8 including the low-temperature maintenance process of maintaining the preset temperature in the said storage chamber at the said 1st temperature after the said introduction process. The cooling means includes a damper for adjusting the amount of cool air supplied to the storage chamber,
The refrigerator according to any one of claims 1 to 9, wherein the control device controls the damper to raise the temperature in the storage chamber to the second temperature in the second step. A heating means for heating the storage chamber;
The refrigerator according to any one of claims 1 to 9, wherein the control device controls the heating means in the second step to raise the temperature in the storage chamber to the second temperature.

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