WO2017043072A1

WO2017043072A1 - Refrigerator

Info

Publication number: WO2017043072A1
Application number: PCT/JP2016/004067
Authority: WO
Inventors: 桂南部; 森　貴代志; 健一柿田; 上迫　豊志
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2015-09-11
Filing date: 2016-09-07
Publication date: 2017-03-16
Also published as: EP3348940A1; CN108027193A; JP2017053583A; EP3348940A4

Abstract

This refrigerator is provided with a storage chamber (107), a blower unit (116) for blowing cool air from a cooling device (115) to the storage chamber (107), and a control unit for controlling the blower unit (116). Due to the blowing of cool air being controlled by the control unit, cool air at a relatively low temperature equal to or less than the freezing point of a food product is guided into the storage chamber (107), and then cool air at a higher temperature is guided in, whereby surface moisture of the food product preserved in the storage chamber (107) is frozen and the entire food product is finally preserved at near-freezing temperature.

Description

refrigerator

The present invention relates to a refrigerator that freezes food in a short time.

In general, partial storage involves freezing foods such as meat and fish at -3 ° C, which can extend the shelf life of food compared to refrigerated (about 4 ° C) and chilled (about 1 ° C). . In addition, partial storage does not solidify the entire food as in freezing, and therefore has the advantage that the partially stored food can be separated with a small force without thawing the solidified food during cooking.

In addition, when food is put into a partial room of a household refrigerator and fine-frozen, if the food is fine-frozen in a short time, the food can be prevented from being oxidized and decomposed by enzymes, so that it can be preserved with a higher freshness.

As an operation method for rapidly cooling food, there is a method of switching to a normal operation for maintaining the storage temperature after performing a rapid cooling operation with a large cooling power (Patent Document 1). The operation is usually performed by changing the flow rate of introducing cool air cooled by the evaporator into the storage room or changing the frequency of introduction of cool air. Therefore, when rapidly cooling, cold air lower than the final reached temperature of the food is introduced into the storage room at a relatively large flow rate.

However, when the rapid cooling method as described above is applied to a partial chamber, after switching from “rapid cooling operation” to “normal operation”, the temperature of the food becomes lower than the target storage temperature and freeze-solidifies (deep There is a possibility of freezing). Also, in order not to impair the advantage that stored food can be cut with a small force, it is important not to increase the cooling capacity during the rapid cooling operation. When a variety of sizes, initial temperatures, and packaged foods are introduced into a household refrigerator, it is very difficult to achieve a delicate balance between rapid cooling and prevention of deep freeze.

Japanese Patent No. 4121197

The present invention has been made in view of the above-described conventional problems, and provides a refrigerator capable of shortening the time until fine freezing of the food and deeply storing the food without deep freezing the food. provide.

Specifically, a refrigerator according to an example of an embodiment of the present invention includes a storage room, a blower that blows cool air from a cooler to the storage room, and a control unit that controls the blower. The control unit includes a first quenching operation that introduces cold air below the freezing point of the food into the storage room, a second quenching operation that introduces cooler air at a higher temperature than the first quenching operation after the first quenching operation, and after the second quenching operation. The blower is controlled so as to perform a normal cooling operation in which cool air having a higher temperature than that of the second rapid cooling operation is introduced, and the blower is controlled so that food is stored at 0 ° C. or lower.

With such a configuration, in the first rapid cooling operation, by introducing a relatively low temperature cold air, the temperature difference between the food and the cold air can be increased to increase the cooling rate. Moreover, freezing can be accelerated | stimulated, encouraging cancellation | release of a supercooled state by giving a temperature change stimulus to the water | moisture content in the supercooled foodstuff by introduce | transducing a higher temperature cold wind by 2nd rapid cooling operation. . Furthermore, by the normal partial preservation cooling operation, the ultimate temperature of the food after completion of the fine freezing and the hardness of the food can be made equal to those of the normal fine frozen food.

Such a configuration can shorten the time until fine freezing without solidifying the food more than normal fine frozen food. Further, with such a configuration, it is possible to approach the final temperature in multiple stages, so that deep freeze can be reliably prevented regardless of the amount and conditions of food. Thereby, the food can be slightly frozen in a short time without deep freezing the food.

In the refrigerator according to the example of the embodiment of the present invention, the second quenching operation time may be set longer than the first quenching operation time. With such a configuration, the temperature of the food after cancellation of supercooling can be brought close to the final temperature in a relatively short time, so that the completion of fine freezing in a short time can be reliably performed.

Further, the refrigerator according to an example of the embodiment of the present invention may be set such that at least the amount of cool air during the first quench operation and the second quench operation is larger than the amount of cool air during normal operation. . With such a configuration, it is possible to promote the progress of cooling and fine freezing of food. Moreover, the temperature change irritation | stimulation with respect to a foodstuff can be enlarged more. As a result, fine freezing in a shorter time can be realized.

Further, in the refrigerator according to an example of the embodiment of the present invention, the blower unit includes a blower that blows cool air from the cooler to the storage chamber, a duct, and a damper provided in the duct. The control unit may be configured to control operations of the blower and the damper. With such a configuration, since the cooling capacity can be changed immediately, a sudden temperature change stimulus can be given to the food, and the supercooled state can be released more reliably. As a result, fine freezing in a short time can be realized more reliably.

In the refrigerator according to the example of the embodiment of the present invention, a forced non-cooling time may be set between the first quenching operation and the second quenching operation. With such a configuration, a large temperature change stimulus can be given to the food, and the supercooled state can be released more reliably. As a result, fine freezing in a short time can be realized more reliably.

Further, the refrigerator according to an example of the embodiment of the present invention may be provided with a high thermal conductivity member on the bottom surface in the storage chamber. With such a configuration, in addition to cooling from the surface exposed to the cold air of the food, cooling from the bottom surface due to heat conduction from the high thermal conductivity member can be added, so that more rapid cooling can be achieved. In addition, by applying a temperature change stimulus from the bottom surface, it is possible to give a greater temperature stimulus to the food, more reliably release the supercooled state, and realize a fine freeze in a shorter time.

FIG. 1 is a front view of the refrigerator according to Embodiment 1 of the present invention. 2 is a cross-sectional view taken along line 2-2 of FIG. FIG. 3 is an enlarged view of a main part of the refrigerator compartment in the first embodiment of the present invention. FIG. 4 is a control block diagram of the refrigerator in the first embodiment of the present invention. FIG. 5 is a control flowchart of rapid cooling operation from detection of the input load of the refrigerator in the first embodiment of the present invention. FIG. 6 is a sequence diagram for detecting the input load of the refrigerator in the first embodiment of the present invention. FIG. 7 is a sequence diagram of the rapid cooling operation of the refrigerator in the first embodiment of the present invention. FIG. 8 is a diagram showing the relationship between the micro freezing start time of the refrigerator and the POV value after 3 days in Embodiment 1 of the present invention. FIG. 9A is a diagram showing changes in the temperature in the storage room of the refrigerator and the surface temperature of the food in Embodiment 1 of the present invention. FIG. 9B is a diagram showing a cooling state of the storage room of the refrigerator in the first embodiment of the present invention. FIG. 10A is a diagram showing the relationship between the temperature gradient ΔT of the refrigerator and the compressor rotation speed of the rapid cooling 1 in Embodiment 2 of the present invention. FIG. 10B is a diagram showing a relationship between the temperature gradient ΔT of the refrigerator and the operation time of the rapid cooling 2 in Embodiment 2 of the present invention. FIG. 11A is a diagram showing changes in the internal temperature of the refrigerator storage room and the surface temperature of the food in Embodiment 3 of the present invention. FIG. 11B is a diagram showing a cooling state of the storage room of the refrigerator in the third embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
1 is a front view of a refrigerator according to Embodiment 1 of the present invention, FIG. 2 is a sectional view taken along the line 2-2 of FIG. 1, and FIG. 3 is an enlarged view of a main part of a refrigerator compartment according to Embodiment 1 of the present invention. FIG. FIG. 4 is a control block diagram of the refrigerator in the embodiment of the present invention, and FIG. 5 is a control flowchart of the rapid cooling operation from detection of the input load of the refrigerator in the embodiment of the present invention.

1 and 2, the refrigerator 101 is divided into an upper stage, a middle stage, and a lower stage, and includes a plurality of storage rooms. Specifically, the upper stage includes a refrigerator compartment 102 having a double door (cold compartment door 102a) on the front, and a first freezer compartment 103 having a drawer door (first freezer door) below the compartment. And an ice making chamber 105 having a drawer door (ice making chamber door 105a) arranged in parallel therewith. The middle stage includes a second freezer compartment 104 having a drawer door (second freezer compartment door 104a) disposed below the freezer compartment 103 and the ice making chamber 105. The lower stage includes a vegetable compartment 106 having a drawer door (vegetable compartment door 106a) arranged at the bottom.

The refrigerator compartment 102, the ice making room 105 and the first freezing room 103 arranged side by side are partitioned by a heat insulating partition wall 111 in the vertical direction. Similarly, the side-by-side ice making chamber 105 and the first freezing chamber 103 and the second freezing chamber 104 are also partitioned by a heat insulating partition wall 111 in the vertical direction. Further, the second freezer compartment 104 and the vegetable compartment 106 are similarly partitioned in the vertical direction by the heat insulating partition wall 111.

The refrigerator 101 is configured such that a heat insulating wall 110 is filled between an outer box 108 and an inner box 109. In the refrigerator 101, a variable temperature chamber 107 is defined as a storage room independent of the refrigerator compartment 102 in the lower part of the refrigerator compartment 102 provided in the upper part. The changing greenhouse 107 is configured as a switching room. In the case of the present embodiment, the variable temperature chamber 107 is located between the first temperature zone (chilled) of the refrigeration temperature zone near 0 ° C. and the first temperature zone and the freezing temperature zone of about −6 ° C. or less. It can be set to a second temperature zone (fine freezing) of about −3 ° C. that is the temperature zone.

Next, the configuration of the cooling system will be described. A cooling chamber 114 is formed behind the second freezing chamber 104 and has a cooler 115 therein. The cooler 115 constitutes a refrigeration cycle for cooling the refrigerator 101 together with the compressor 112 installed in the upper machine room 113. The cooling chamber 114 is provided with a blower fan 116 that forcibly circulates the cool air heat-exchanged by the cooler 115. Above the blower fan 116, a damper device 117a that distributes the cold air flowing into the refrigerating chamber 102 and a damper device 117b that distributes the cold air flowing into the variable temperature chamber 107 are arranged. Each storage room can be used with a separate temperature zone. Specifically, for example, the refrigerator compartment 102 is set to a temperature range of about 2 to 3 ° C., and the vegetable compartment 106 is set to a temperature range of about 2 to 5 ° C. for use. Is possible. The first freezer compartment 103 and the second freezer compartment 104 can be used with the internal temperature set in a temperature range of about −18 to −20 ° C. By setting it as such a structure, the temperature range suitable for preservation | save of a foodstuff is selected in each store room, and higher freshness and long-term preservation | save can be implement | achieved by storing a foodstuff.

Next, the structure of the changing room 107 and the lighting device 121 installed on the top surface of the changing room 107 will be described with reference to FIGS. 3 and 4.

As shown in FIG. 3, the temperature change chamber 107 has a top cover 122 made of synthetic resin that can be used as a shelf 118 positioned at the bottom of the refrigerator compartment 102, and a front and rear direction below the top cover 122. It is composed of a synthetic resin storage case 123 that can be pulled out and an opening / closing door 124 that can be opened and closed at the front opening of the upper surface cover 122 of the variable temperature chamber 107. The open / close door 124 is configured to be in close contact with the front wall 123b of the storage case 123 when closed, so that the inside of the variable temperature chamber 107 becomes a substantially sealed space. Moreover, the open / close door 124 is made of a highly transparent synthetic resin so that food stored in the interior can be visually recognized.

Furthermore, a door opening / closing detection unit 127 is provided on the back wall surface of the variable temperature chamber 107 so that the opening / closing door 124 is fitted to the rear wall 123a of the storage case 123 when the opening / closing door 124 is closed. Further, in the present embodiment, an aluminum bottom plate 128 is fitted on the bottom surface of the storage case 123 to improve the cooling performance and improve the visibility by diffusing the illumination from the lighting device 121. Is not particularly essential.

Further, a rear side duct 125 for changing the temperature of the greenhouse, which guides the cold air distributed by the damper device 117 to the temperature changing room 107, is formed behind the rear wall surface of the temperature changing room 107. Further, a variable temperature ceiling top duct 126 that is downstream of the variable temperature greenhouse rear duct 125 is disposed on the top surface of the variable temperature greenhouse 107. The variable temperature ceiling top duct 126 includes a heat insulating duct member 126a formed of a heat insulating foam heat insulating member, and a synthetic resin duct cover 126b serving as a decorative plate covering the outer periphery of the heat insulating duct member 126a. The variable temperature ceiling top duct 126 forms a duct together with the upper surface cover 122, and a cold air outlet 129 for discharging the cold air into the variable temperature chamber 107 is formed at a position that becomes the upper surface portion of the storage case 123.

Also, in the variable temperature chamber 107, a lighting device 121 for irradiating the room is installed in the duct cover 126a on the opening door side in front of the depth center position of the variable temperature ceiling duct 126.

Next, the refrigerator compartment 102 is provided with a refrigerator compartment door switch 130 for detecting the open / closed state of the refrigerator compartment door 102a, and the temperature zone and the operation mode of the variable temperature chamber 107 can be set at an arbitrary location inside or outside the refrigerator 101. A setting unit 131 for switching is installed. Further, a signal S 1 from the refrigerator door switch 130, a signal S 2 from the setting unit 131, and a signal S 3 from the door opening / closing detection unit 127 are input to the control microcomputer 132. Further, the control microcomputer 132 outputs a signal S4 to the compressor 112, a signal S5 to the blower fan 116, a signal S6 to the damper device 117a, and a signal S7 to the damper device 117b, thereby performing a predetermined cooling operation. Done.

The operation and action of the refrigerator configured as described above will be described below with reference to FIGS.

First, the opening / closing door 124 is closed and the refrigeration room door switch 130 is refrigerated room door in a state in which the setting unit 131 sets the temperature range of the variable temperature room 107 to the second temperature range (partial). The closing of 102a is detected (STEP 1). Then, starting from the fact that the refrigeration room door switch 130 detects the closing of the refrigeration room door 102a (STEP 1), the food supply presence / absence determination unit 134 determines the presence or absence of load application. Specifically, when the compressor 112 has been running for 5 minutes or more after starting and is operated at a predetermined number of rotations determined by the outside air temperature (STEP 2), it is determined whether or not the inside of the variable temperature chamber 107 is to be rapidly cooled. Rapid cooling start determination is started (STEP 3). If the time after starting the compressor 112 does not reach 5 minutes in STEP2, the process proceeds to STEP3 when 5 minutes have passed.

When it is determined in STEP 3 that there is no load, normal fine freezing control is performed (STEP 4). On the other hand, when it is determined in STEP 3 that the load is applied, a predetermined rapid cooling operation is started. Although details of the rapid cooling operation will be described later, the outline is the rapid cooling 1 (first rapid cooling operation) of STEP 5 and then the rapid cooling 2 (second rapid cooling operation) of STEP 6 is performed. Further, after completion of the predetermined rapid cooling operation, the deep freeze protection operation of STEP 7 is performed.

In addition, it is desirable that a rapid cooling release determination (STEP 8) is performed between the rapid cooling 1 of STEP 5 and the rapid cooling 2 of STEP 6 to determine again whether or not a load is applied. The rapid cooling release determination (STEP 8) is the same as the rapid cooling start determination in STEP 2 to STEP 3, which will be described later.

The rapid cooling release determination is determined based on the temperature gradient (degree of temperature change) of the variable temperature chamber temperature sensor 133 when the damper device 117b for the variable temperature chamber (partial room) 107 is forcibly closed for a predetermined time. It may be configured.

Next, in FIG. 6, a detection sequence of the food input presence / absence determination unit 134 which is the rapid cooling start determination in STEP 2 to STEP 3 will be described.

When the rapid cooling start determination is started, the damper device 117a for the refrigerator compartment is forcibly opened, and the damper device 117b for the variable temperature chamber (partial chamber) 107 is forcibly closed. Further, the compressor 112 is operated for 3 minutes with the discharge cold air flow rate being a predetermined amount while maintaining the predetermined rotation speed. After 3 minutes, the damper device 117a for the refrigerator compartment is forcibly closed, and the damper device 117b for the variable temperature chamber (partial chamber) 107 is forcibly opened. Temperatures at 4 minutes and 5 minutes after the start of the input load detection sequence are detected by the variable temperature sensor 133, and a temperature gradient ΔT is calculated. When the temperature gradient ΔT value is larger than a predetermined threshold value determined by the partial chamber temperature after 4 minutes, it is determined that there is an input load, and the rapid cooling operation is started.

In the above detection sequence, the cooling of the temperature changing room 107 is stopped for 3 minutes from the start of detection, so that the temperature change state of the temperature changing room 107 can be stabilized and the temperature gradient ΔT can be stabilized. Normally, during the partial operation, the rotation speed of the compressor 112, the flow rate of the discharged cold air, and the load amount already stored in the variable temperature chamber 107 are not constant, and the internal temperature is constantly increasing or decreasing. It is in. Even when these conditions immediately before detection are different, it is required to be able to determine with a certain threshold value. The temperature gradient ΔT value can mainly reflect the input heat load by continuing the operation under the above-mentioned predetermined conditions for 3 minutes prior to the start of cooling of the temperature changing chamber 107. As a result, the correct determination can be made stably regardless of the driving situation immediately before detection.

In addition, since the cooling is started after the temperature in the temperature change chamber 107 is increased in the first three minutes, the absolute value of the temperature gradient ΔT can be made larger than immediately when the cooling is started. This expands the temperature gradient ΔT value and the S / N ratio of the measurement variation of the variable temperature sensor 133. As a result, the accuracy of determination based on the temperature gradient ΔT value can be increased.

In addition, by intensively cooling the refrigerator compartment 102 in the first three minutes, the temperature of the refrigerator compartment 102 is lower than that during normal operation. Therefore, when the temperature of the refrigerator compartment 102 is adjusted again, the damper device 117a is closed longer than usual. As will be described later, in order to speed up the surface micro freezing of food, it is important that the damper device 117a is closed and only the damper device 117b is opened after the rapid cooling is started. The above-described preliminary cooling of the refrigerator compartment 102 has an effect of extending the continuous opening time of the damper device 117b, and promotes surface microfrozen.

3 minutes later, the damper device 117a is closed and the damper device 117b is opened, so that the temperature changing room 107 is cooled at the maximum speed. Immediately after the damper device is opened and closed, the temperature gradient may be affected by the timing of opening and closing, etc., so the determination is made using the temperature gradient ΔT value between 4 minutes and 5 minutes after the temperature in the variable temperature chamber 107 is stabilized as an index. Done.

When a certain amount of heat load is applied (a in FIG. 6) compared to the case where no heat load is applied to the temperature change chamber 107 (b in FIG. 6), the inside of the cabinet measured by the temperature change temperature sensor 133 is measured. The decrease in temperature becomes slower and the temperature gradient ΔT value becomes smaller.

The threshold value of the temperature gradient ΔT is changed and set according to the following various conditions. When the internal temperature after 3 minutes is relatively high, the temperature is likely to drop during the latter 2 minutes of cooling, so the absolute value of the threshold value of the temperature gradient ΔT is set to be relatively large. On the other hand, when the internal temperature after 3 minutes is relatively low, the absolute value of the threshold value of the temperature gradient ΔT is set relatively small. When the outside air temperature is relatively high, the cooling capacity for the latter half 2 minutes tends to be relatively low, so the absolute value of the threshold value of the temperature gradient ΔT is set to be relatively small. When the rotational speed of the compressor 112 is relatively high, the cooling capacity is relatively high, and thus the absolute value of the threshold value of the temperature gradient ΔT is set to be relatively large.

When determining the presence or absence of the input heat load in the detection sequence, especially when the temperature gradient ΔT value is close to the threshold value, whether it can be correctly determined is determined stochastically according to the normal distribution. The first misjudgment that determines that there is no input load (does not cool rapidly) in the misjudgment and the second misjudgment that determines that there is no input load (quickly cools). There is. The threshold value of the temperature gradient ΔT may be set so that the probability of the first misjudgment and the second misjudgment are equal. If it is reasonable in use that the input heat load can be cooled more reliably, the threshold value of the temperature gradient ΔT is larger than the case of the above equal probability so that the first erroneous determination is minimized. Is set. On the contrary, when it is disadvantageous that the object to be cooled already cooled in the variable temperature chamber 107 is excessively cooled, the above-mentioned equal probability is set so that the second misjudgment is minimized. It is also possible to set the threshold value of the temperature gradient ΔT smaller than the case.

In order to improve the probability of correct determination, it is effective to make the amount of heat intrusion from the wall surface into the temperature change chamber 107 constant. The configuration in which the variable temperature chamber 107 is provided in the refrigerating room 102 can keep the temperature change of the refrigerating room 102 within a predetermined range regardless of the change in the outside air temperature. It is effective.

When the temperature in the temperature changing chamber 107 becomes equal to or higher than a predetermined temperature, and when the door 124 is opened for a predetermined time or longer, the following rapid cooling or normal partial operation is performed regardless of the detection sequence of FIG. Cooling may be initiated. As a result, the room temperature of the partial room (conversion room 107) can be immediately lowered without spending time in the detection operation, and deterioration of freshness due to an increase in food temperature can be prevented.

Next, the rapid cooling operation sequence shown in FIG. 7 will be described. In the present embodiment, the rapid cooling operation includes rapid cooling 1 (first rapid cooling operation) having a relatively large cooling capacity and rapid cooling 2 (second rapid cooling operation) in which the cooling capacity is larger than the normal partial operation and smaller than the rapid cooling 1. In the rapid cooling 1 operation, the rotational speed of the compressor 112 is higher than that in the normal operation, and the flow rate (air volume) for introducing cold air into the variable temperature chamber 107 is set to be large. Further, the damper device 117b to the variable temperature chamber 107 is forcibly set to an open state, and the damper device 117a to the refrigerator compartment 102 is set to be more difficult to open. The compressor 112 is set so as not to be stopped.

During the second rapid cooling operation, the temperature of the temperature changing greenhouse 107 is adjusted so that the food does not cool above the predetermined temperature. The rapid cooling 2 is operated under some of the operating conditions during the rapid cooling 1 operation. Or you may drive | operate on the conditions between the driving | running conditions at the time of the said rapid cooling 1 driving | operation, and the driving | running conditions at the time of normal driving | operation.

In the present embodiment, there is an effect of promoting the fine freezing of food by the rapid cooling 1 having a large cooling capacity. On the other hand, if the rapid cooling 1 is continued, the variable temperature greenhouse 107 having a limited capacity is mainly cooled. Therefore, the cooling heat of the cooler 115 cannot be completely discharged into the chamber, and the temperature of the cooler 115 continues to decrease. Tend. As a result, the operation of the compressor 112 must be stopped for low-pressure protection. As will be described later, in order to promote fine freezing, it is necessary to continue cooling continuously. Therefore, it is necessary to avoid a temperature drop of the cooler 115 beyond a predetermined level. For this reason, in the present embodiment, the rapid cooling 1 is completed in 30 minutes, and the rapid cooling 2 having a lower rotational speed is started. In the rapid cooling 2, the rotational speed of the compressor 112 is set so as to prevent the temperature of the cooler 115 from falling below a predetermined level even when continuously operating. In addition, when the temperature of the cooler 115 still decreases, the damper device 117a may be configured to be forcibly opened.

Further, by providing the quick cooling 2 having a cooling capacity lower than that of the quick cooling 1, the food which has already been slightly frozen in the variable temperature chamber 107 is deep-frozen to be hardened, frosted in the variable temperature chamber 107, There is also an effect of avoiding that the food placed adjacent to 107 is slightly frozen unexpectedly.

In order to rapidly freeze food, it is necessary to keep the food continuously cooled for a predetermined time for the following reasons. When the food is slightly frozen, if the surface layer is slightly frozen, the specific heat is about half that of the unfrozen portion inside the food, and the thermal conductivity is about four times. If the cooling is temporarily stopped in this situation, the heat of the unfrozen part is easily transmitted to the finely frozen part by heat conduction, so that the temperature of the finely frozen part is likely to rise again. As a result, the temperature of the microfrozen portion once easily rises to 0 ° C., and melting begins. Repeated micro freezing and thawing is not preferable because the food is physically deteriorated and the quality is lowered.

In order to realize surface micro-freezing rapidly, the micro-freezing layer grows to such an extent that the micro-freezing layer itself exhibits a latent heat storage effect and exhibits a heat insulation effect so that the heat inside the food does not transfer to the outermost layer. It is necessary to make it. For example, in the present embodiment, the fine frozen layer is grown to a thickness of about 1 mm. In this way, a finely frozen layer can be reliably formed on the food surface layer. In addition, when the micro frozen layer is generated in this way, the time until the micro frozen layer is generated is not affected easily by the supercooling phenomenon or the like and is relatively stable.

Foods such as meat and fish contain phospholipids in the cell membrane and neutral fat in the subcutaneous tissue, but their constituent unsaturated fatty chains are auto-oxidized by contact with oxygen to produce hydroxyperoxide. Arise. Ingestion of hydroxyperoxide is harmful because DNA is damaged by the radical reaction in the body and the physiologically active substance is oxidized.

When the micro freezing layer is uniformly formed on the entire surface layer of the food by the rapid cooling operation as described above, the ice of the extracellular fluid is substantially smaller than the water because the diffusion coefficient of oxygen is two orders of magnitude or less. The inside of food can be shielded from oxygen. Since oxygen is essential for the above-mentioned auto-oxidation, the production of hydroxyperoxide can be prevented by blocking the cells and the inside of food from oxygen. In this way, by facilitating surface freezing, the oxidation of foods containing fats and oils is suppressed, and values such as oxidation index AV (Acid Value), POV (Peroxide Value), and TBA (Thiobarbitur Acid) Rise is suppressed.

FIG. 8 is a diagram showing the relationship between the surface micro-freezing time when the food is micro-frozen and the POV value after 3 days. The POV value on the vertical axis is shown relative to the POV value on day 0 as 1.0. It is found in the two fish foods that the oxidation index value increases during the storage days of 3 days when the surface micro freezing time exceeds a predetermined time. In order to suppress the increase in the POV value during the storage period of 3 days and to substantially prevent oxidation, it is effective that the food surface is slightly frozen within 8 hours and the contact between oxygen and fats and oils is blocked. To be found. Similarly, it is found that if the food is microfrozen within 8 hours, the K value does not rise in 3 days.

In addition, in the case of beef and pork, it is known that the oxidation index value after 7 days does not increase if surface freezing is performed within 8 hours.

In consideration of these, in this embodiment, the cooling capacity during the rapid cooling operation is set so that the food surface is slightly frozen within 8 hours.

It should be noted that the rapid cooling 1 may be set so that during the rapid cooling 1, the rapid cooling release determination for determining again the continuation of the rapid cooling operation is performed. The cancellation determination is basically the same as the detection sequence shown in FIG. 6, but the threshold value of the temperature gradient ΔT is separately determined. The rapid cooling cancellation determination may be set to be performed a plurality of times. Even if the second misjudgment is made by the detection sequence, the rapid cooling operation is stopped halfway due to the rapid cooling cancellation determination, so that unnecessary rapid cooling operation is stopped and the energy consumption is not increased more than necessary. Can be.

When rapid cooling 2 is completed, normal partial operation is performed. If the temperature of the cooler 115 is lower than a predetermined temperature during the operation transition, it may be determined that cooling is unnecessary and the compressor 112 may stop. Usually, while the compressor 112 is stopped, the blower fan 116 that blows the cool air of the cooler 115 into the refrigerator 101 is stopped. However, the blower fan 116 may be operated when the operation is shifted. As a result, the temperature rise of the cooler 115 can be promoted, and the stop time of the compressor 112 can be made shorter than usual. The shorter the stop time of the compressor 112, the shorter the time until fine freezing for the above-mentioned reason, and a favorable result can be obtained for maintaining freshness.

After returning to the normal partial operation, as shown in FIG. 7, a protection time is provided for continuing the normal partial operation without starting the rapid cooling operation for a predetermined time. If there is a food that has been slightly frozen in the variable temperature chamber 107 before the heat load is applied, the temperature of the food temporarily decreases due to the rapid cooling operation, and the food may become harder than the slight freezing. By providing the protection time, during the protection time, the food temperature approaches substantially the same temperature as during normal partial operation, and the food hardness also returns. If the protection time is not provided, when the heat load is continuously applied, the existing microfrozen food approaches freezing from microfrozen, and the merit of microfrozen is reduced. Can be prevented.

¡The longer the protection time is set, the easier the temperature of the existing microfrozen food will return to the microfrozen temperature. Regarding the length of protection time, taking into account the temperature rise during the protection time and the temperature rise during regular defrost operation, the temperature of the food is within the range of the freezing temperature during the standard storage period of food. Is set to fit. Or during the preservation | save period of a standard foodstuff, you may set so that the force required when cutting a foodstuff may not rise beyond a predetermined value.

As an example, FIG. 7 shows an example in which the rapid cooling operation (rapid cooling 1 and rapid cooling 2) time is set to 2.5 hours and the protection time is set to 3 hours. In this case, one quench cycle is 5.5 hours, which is approximately equal to the general breakfast, lunch and dinner preparation time cycle. Therefore, even if the partial room temperature rises at a certain meal preparation time and the rapid cooling operation is started, the rapid cooling can be performed similarly at the next meal preparation time, and the freshness of the existing microfrozen food is reliably maintained. be able to.

If a thermal load is applied during the protection time, only the detection sequence is activated and a rapid cooling start determination is made. If it is determined that rapid cooling is required, the rapid cooling starts immediately after the protection time is over.

As described above, the refrigerator 101 according to the present embodiment controls the storage room (transformer 107), the air blowing unit (blower fan 116) that blows cool air from the cooler 115 to the storage room, and the air blowing unit. And a control unit (control microcomputer 132). By controlling the air volume (flow rate) of the cool air blown by the control unit, the surface of the food stored in the storage room is slightly frozen, and the food is stored at the slightly freezing temperature. With such a configuration, the contact between the food and oxygen is blocked by the micro-frozen layer to prevent oxidation, and the food can be easily separated and separated, and the flavor of the food is not deteriorated. The food can be stored fresh.

Moreover, in the refrigerator 101 of this Embodiment, a ventilation part is a duct (refrigeration room duct 120) which ventilates the cold air from the cooler 115 to a storage room, a damper (damper device 117a) provided in the duct, A temperature sensor that detects the temperature in the storage chamber (temperature change temperature sensor 133). In addition, the control unit forcibly opens the damper device for a predetermined time, rapidly micro-freezes the surface of the food stored in the storage chamber, and the temperature sensor detects the temperature so that the food is stored at the micro-freezing temperature. The damper device is controlled to open and close based on the above. With this configuration, rapid cooling starts immediately after the food is added, and the contact between oxygen and the food can be prevented in a shorter time, preventing oxidation of the food. Can be saved.

Further, the refrigerator 101 of the present embodiment is configured such that the damper device is forcibly opened for a predetermined time and the compressor is continuously operated. With such a configuration, contact with oxygen can be blocked in a shorter time to prevent oxidation, and stored food can be stored fresh.

In addition, the refrigerator 101 of the present embodiment includes a storage room, a blower unit 116 that blows cool air from the cooler 115 to the storage room, a temperature sensor 133 that detects the temperature in the storage room, and food input into the storage room And a food input presence / absence determination unit 134 for determining presence / absence. The food supply presence / absence determination unit 134 is configured to forcibly stop the air blowing unit 116 for a predetermined time and determine whether or not food is input into the storage room based on the temperature gradient (degree of temperature change) of the temperature sensor 133. . With such a configuration, it is possible to determine whether or not food is put into the storage chamber with a simple configuration.

In addition, the food input presence / absence determining unit 134 forcibly stops the air blowing unit 116 for a predetermined time, and then forcibly operates the air blowing unit 116 for a predetermined time so that the temperature of the temperature sensor 133 during the forced operation of the air blowing unit 116 is reached. Based on the inclination, it is configured to determine whether or not food is put into the storage chamber. With such a configuration, it is possible to reliably determine whether or not food is put into the storage chamber with a simple configuration.

Further, the food input presence / absence determination unit 134 may be configured to be executed a plurality of times and determine whether or not food is input into the storage chamber. With such a configuration, it is possible to more reliably determine whether or not food is put into the storage chamber with a simple configuration.

Moreover, the refrigerator 101 of this Embodiment may be provided with the storage room opening / closing detection part 127 which detects opening / closing of the storage room (transformer 107). With such a configuration, since the control unit 132 is executed starting from the opening / closing detection of the storage chamber opening / closing detection unit 127, it is possible to more reliably prevent the food from being oxidized and to store the stored food freshly. Can do.

Further, the storage room (transformer room 107) may be configured to be built in a part of another storage room (refrigerated room 102) and temperature-controlled independently of the other storage room. With such a configuration, the finely frozen layer once generated can be stably maintained, and the antioxidant effect can be maintained.

In order to promote deep freezing of food while preventing deep freeze, both the optimal cooling rate and the stimulus for releasing supercooling are utilized to control the temperature in the storage room by the controller. The

FIG. 9A is a diagram showing a change in the internal temperature of the refrigerator storage chamber and the surface temperature of the food in Embodiment 1 of the present invention, and FIG. 9B is the refrigerator storage chamber in Embodiment 1 of the present invention. It is a figure which shows the cooling state.

9A and 9B, the rapid cooling 1 aims at rapid cooling until the surface temperature of the food is near or below the freezing point. In the rapid cooling 1, as shown in FIG. 7, in order to increase the temperature difference between the food and the cold air, the rotational speed of the compressor 112 is increased from R2 to R3, for example, or the heat transfer coefficient is increased. Various conditions are set so that the rotational speed of the blower fan 116 is increased from VF2 to VF6, for example, and the air volume is increased. Note that R2, R3, VF2, and VF6 mean arbitrary rotational speeds, and in this embodiment, as shown in FIGS. 7 and 10A, they have a magnitude relationship of R2 <R3 and VF2 <VF6. .

Also, when the food surface temperature is below the solidification temperature, rapid cooling itself has a side that tends to cause overcooling cancellation compared to slow cooling.

On the other hand, after the rapid cooling 2, the purpose is to release the supercooling rather than the rapid cooling 1. Further, after the rapid cooling 2, the set temperature is set to be gradually higher than the rapid cooling 1 so that the final reached temperature of the whole food is from the solidification temperature to the standard fine freezing temperature. After the rapid cooling 2, the internal temperature fluctuates up and down across the set temperature by opening and closing the damper device 117a. If the food is unfrozen at this point, this temperature fluctuation will be a stimulus and the supercooling release will be accelerated. By continuing normal control operation, the food temperature approaches the standard micro freezing temperature. Thus, according to the configuration of the present embodiment, the food that has been microfrozen in the refrigerator 101 does not deep freeze at any point in time. For this reason, it is possible to maintain good handling properties such as easy cutting of food stored during cooking.

(Embodiment 2)
FIG. 10A is a diagram showing the relationship between the temperature gradient ΔT of the refrigerator in Embodiment 2 of the present invention and the compressor rotation speed of the rapid cooling 1, and FIG. 10B is the temperature gradient of the refrigerator in Embodiment 2 of the present invention. It is a figure which shows the relationship between (DELTA) T and the driving | running time of the rapid cooling 2. FIG. In addition, description of the same part as Embodiment 1 is abbreviate | omitted, and only a different part is demonstrated.

In the rapid cooling determination sequence in FIG. 6, under a certain condition, the magnitude of the temperature gradient ΔT value is substantially proportional to the input heat load. In the refrigerator 101 of the present embodiment, operation control for increasing the cooling amount in proportion to the input heat load amount is performed. As shown in FIG. 10A, when the absolute value of the temperature gradient ΔT is larger than ΔT0, rapid cooling is performed, and the rotation speed is increased from R2 to R3. When the absolute value is larger than the temperature gradient ΔT1, the rotational speed is further increased to R4. Note that R2, R3, and R4 represent arbitrary rotational speeds, and in the present embodiment, as shown in FIG. 10A, there is a magnitude relationship of R2 <R3 <R4. In this way, when the input heat load is large, the time until the surface layer micro freezing is reliably shortened by lowering the temperature of the cooler 115 and increasing the cooling capacity. At this time, if the time of the rapid cooling 1 is extended, adverse effects such as frosting in the variable temperature greenhouse 107 and freezing of food in the adjacent storage room are produced, so it is desirable that the time is not extended.

Further, as shown in FIG. 10B, when the absolute value of the temperature gradient ΔT is between ΔT0 and ΔT1, the time of the rapid cooling 2 is set to t1, but at the temperature gradient ΔT1 or more, it is proportional to the value of the temperature gradient ΔT. Time is extended. However, even if a thermal load having a temperature gradient ΔT2 or more is applied, the rapid cooling 2 time is not set to be extended to t2 or more. The upper limit time t2 of the rapid cooling 2 is appropriately set so as not to adversely affect frost formation and food freezing. As described above, the refrigerator 101 according to the present embodiment is configured such that the rapid cooling operation condition is adjusted in accordance with the input heat load, so that it is possible to reliably shorten the time until the surface layer micro freezing. On the other hand, adverse effects due to excessive cooling and unnecessary increase in operating costs can be prevented.

(Embodiment 3)
FIG. 11A is a diagram showing changes in the internal temperature of the refrigerator storage chamber and the surface temperature of the food in Embodiment 3 of the present invention, and FIG. 11B is the refrigerator storage chamber in Embodiment 3 of the present invention. It is a figure which shows the cooling state. In addition, description of the same part as Embodiment 1 is abbreviate | omitted, and only a different part is demonstrated.

Unlike the first embodiment, this embodiment is provided with a forced non-cooling time between the rapid cooling 1 and the rapid cooling 2, and the water surface temperature is raised and lowered to promote the release of the supercooling of water. It is configured as follows. Specifically, the operation of the compressor 112 is stopped for about 10 minutes, or the damper device 117a is set to be forcibly closed, so that the cooling of the storage room (conversion room 107) is stopped. When the surface temperature of the food is below the freezing point at the end of the rapid cooling 1, the temperature rise during the stop is a stimulus and the surface layer is intended to be slightly frozen. With such a configuration, it is possible to prevent oxidative degradation by promoting fine freezing of the food while preventing the temperature from becoming deep frozen.

As described above, the present invention provides a refrigerator capable of slightly freezing food in a short time without deep freezing the food. Therefore, the present invention can be applied not only to household use but also to commercial refrigerators, and can be widely used for showcases, prefabricated refrigerators, and the like.

101 refrigerator 102 refrigerator compartment (storage room)
107 Changing greenhouse (storage room, partial room)
112 Compressor 115 Cooler 116 Blower Fan (Blower Unit)
117, 117a, 117b Damper device (damper)
120 Cold room duct (duct)
REFERENCE SIGNS LIST 121 Illuminating device 122 Top cover 123 Storage case 123a Rear wall 123b Front wall 124 Open / close door 125 Changing room rear duct 126 Changing room top duct 126a Thermal insulation duct member 126b Duct cover 127 Door opening / closing detection part (storage room opening / closing detection part)
128 Bottom plate 129 Cold air outlet 130 Cold room door switch 131 Setting unit 132 Control microcomputer (control unit)
133 Temperature change sensor (temperature sensor)
134 Food input presence / absence determination unit

Claims

A storage room, a blower that blows cool air from a cooler to the storage room, and a control unit that controls the blower, wherein the control part introduces cold air below the freezing point of the food into the storage room A first quenching operation, a second quenching operation that introduces cooler air than the first quenching operation after the first quenching operation, and a cooler air that is hotter than the second quenching operation after the second quenching operation A refrigerator configured to control the air blowing unit so that a normal cooling operation is performed, and the food is stored at 0 ° C. or less by the control unit.
The refrigerator according to claim 1, wherein the second quenching operation time is set longer than the first quenching operation time.
3. The refrigerator according to claim 1, wherein at least the amount of cold air during the first quenching operation and the second quenching operation is set larger than the amount of cold air during the normal cooling operation.
The blower unit includes a blower that blows the cool air from the cooler to the storage chamber, a duct, and a damper provided in the duct, and the control unit operates the blower and the damper. The refrigerator as described in any one of Claim 1 to 3 comprised so that control might be carried out.
The refrigerator according to any one of claims 1 to 4, wherein a forced non-cooling time is set between the first quenching operation and the second quenching operation.
The refrigerator according to any one of claims 1 to 5, wherein a high thermal conductivity member is provided on a bottom surface of the storage chamber.