Refrigerator

Abstract

The invention provides a refrigerator capable of preventing frozen food from becoming dry and maintaining the quality of the frozen food. The refrigerator according to the present invention comprises: a refrigeration cycle including a compressor and a cooler; a cooler chamber for accommodating the cooler; a freezing chamber which accommodates the first container and has an open front; a freezing chamber door capable of opening and closing the opening of the freezing chamber; and a freezing fan for conveying the air cooled by the cooler to the freezing chamber, in which, in a steady state, the time average temperature of the bottom surface of the first container is lower than the time average temperature of the air in the storage space of the first container.

Description

Technical Field

[0001] The present invention relates to a cold storage. Background Art

[0002] There are known refrigerators that can switch the flow of cold air delivered to the freezer compartment. For example, Patent Document 1 discloses a technology that blows cold air out of one opening and draws air in through another opening when the air supply fan rotates forward, and blows cold air out of the other opening and draws air in through one opening when the air supply fan rotates reversely.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-232879 Summary of the Invention

[0006] Technical problem to be solved by the invention

[0007] The technology disclosed in Patent Document 1 switches the flow of cold air to agitate the air within the freezer compartment to achieve a uniform temperature. Regarding the timing of the switch, only periodic or irregular switching is mentioned. Furthermore, there are states where the air supply fan is stopped, such as during refrigeration or defrosting operation, but the document does not specify the order in which the air supply fan's rotation direction should be switched from this state.

[0008] Technical means to solve the problem

[0009] In order to solve the above-mentioned problem, for example, the structure described in the technical solution claimed for protection is adopted. The cold storage of the present invention includes multiple technical solutions for solving the above-mentioned problems. For example, it includes: a refrigeration cycle including a compressor and a cooler; a cooler chamber for storing the cooler; a freezer chamber for storing a first container and having an opening in the front; a freezer chamber door capable of opening and closing the opening of the freezer chamber; and a refrigeration fan for conveying air cooled by the cooler to the freezer chamber, wherein, in a stable state, the time-averaged temperature of the bottom surface of the first container is lower than the time-averaged temperature of the air in the storage space of the first container. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a front view of the refrigerator in the embodiment.

[0011] Figure 2 It is a longitudinal sectional view of the cold storage in the embodiment.

[0012] Figure 3 It is a front view showing the internal structure of the cold storage according to the embodiment.

[0013] Figure 4 It is a structural diagram of a refrigeration cycle of a refrigerator according to an embodiment.

[0014] Figure 5 It is a perspective view showing the structure of a door and a container of the refrigerator according to the embodiment.

[0015] Figure 6 This is a diagram showing the flow of air during normal refrigeration operation.

[0016] Figure 7 It is a diagram showing the flow of air during the container cooling and freezing operation.

[0017] Figure 8 This is a graph showing temperature changes in the freezer compartment in Example 1.

[0018] Figure 9 This is a flowchart showing the control immediately after the lower freezer compartment door is closed in the first embodiment.

[0019] Figure 10 This is a flowchart showing the control when the freezing compartment is in a stable state in the first embodiment.

[0020] Figure 11 It is a graph showing the temperature changes (steady state) of food and ambient air in a comparative example.

[0021] Figure 12 This is a graph showing the temperature changes (steady state) of the food and the surrounding air in Example 1.

[0022] Figure 13 This is a graph showing the temperature change in the freezer compartment immediately after the lower freezer compartment door is closed in Example 2.

[0023] Figure 14 This is a flowchart showing the control immediately after the lower freezer compartment door is closed in the second embodiment.

[0024] Figure 15 Graph showing temperature changes of food and ambient air in a comparative example (immediately after the door is closed).

[0025] Figure 16 This is a graph showing the temperature changes of the food and the surrounding air in Example 2 (immediately after the door is closed).

[0026] Figure 17 This is a graph showing temperature changes in the freezer compartment immediately after the lower freezer compartment door is closed in a modified example of Example 2.

[0027] Figure 18A This is a schematic diagram of the first air duct using dampers to switch the circulation direction.

[0028] Figure 18BThis is a schematic diagram of the second air duct using dampers to switch the circulation direction.

[0029] Figure 19 This is a diagram showing the structure of a container in a modified example of Example 1.

[0030] Description of Reference Numerals

[0031] 1···cold storage (refrigerator), 2···refrigerating room, 3···ice making room, 4···upper freezer, 5···lower freezer, 6···vegetable room, 7···freezer, 8a···evaporator compartment for refrigeration, 8b···evaporator compartment for freezing, 9a···refrigerating fan, 9b···freezing fan, 10···cold storage body, 10a···outer box, 10b···inner box, 11···air supply path for refrigerating room, 11a···Refrigerator compartment outlet, 12···Freezer compartment air supply duct, 12a···First freezer compartment outlet, 12b···Second freezer compartment outlet, 13···Vegetable compartment air supply duct, 13a···Vegetable compartment outlet, 14a···Refrigerator evaporator, 14b···Freezer evaporator, 15a, 15b, 15c···Refrigerator compartment return port, 17···Freezer compartment return port, 18···Vegetable compartment return air duct, 1 8a···Vegetable compartment return port, 19···Vegetable compartment damper, 24···Compressor, 25···Vacuum insulation material, 28, 29, 30···Insulation partition wall, 40a···Refrigeration evaporator temperature sensor, 40b···Freezing evaporator temperature sensor, 41···Refrigerator compartment temperature sensor, 42···Freezer compartment temperature sensor, 43···Vegetable compartment temperature sensor, 210a, 210b···Refrigerator Room door, 301···Ice making room container, 310···Ice making room door, 401···Upper freezer compartment container, 410···Upper freezer compartment door, 501···Upper container of lower freezer compartment, 502···Middle container of lower freezer compartment, 503···Lower container of lower freezer compartment, 510···Lower freezer compartment door, 601···Upper container of vegetable compartment, 602···Lower container of vegetable compartment, 610···Vegetable compartment door. DETAILED DESCRIPTION

[0032] Hereinafter, embodiments of the present invention will be described.

[0033] In the description of the embodiments, when multiple conditions connected by "or" are considered to be satisfied, this also includes the meaning that any one of the multiple conditions is satisfied individually, or any one of the multiple conditions is satisfied in combination. For example, the statement "If condition A or condition B is satisfied, process C is executed" includes any of "If condition A is satisfied, process C is executed," "If condition B is satisfied, process C is executed," and "If either or both conditions A or B are satisfied, process C is executed."

[0034] This embodiment specifically considers the storage of frozen food in packaging bags. If the food temperature remains higher than the air temperature inside the bag for a prolonged period, moisture tends to sublime from the food surface, depositing as frost on the inside of the bag. Repeatedly, this process can cause the food to dry out.

[0035] <Basic structure of cold storage>

[0036] First, refer to Figures 1 to 4 The basic structure of the refrigerator in this embodiment will be described. Figure 1 This is a front view of the refrigerator in this embodiment. Figure 2 yes Figure 1 AA cross-section diagram, Figure 3 yes Figure 2 BB cross-section diagram, Figure 4 It is a schematic diagram showing the configuration of a refrigeration cycle of the refrigerator according to this embodiment.

[0037] like Figure 1 As shown, the refrigerator body 10 of the refrigerator 1 is open to the front, and the storage compartments are formed in the order of a refrigerator compartment 2, an ice-making compartment 3 arranged side by side on the left and right, an upper freezer compartment 4, a lower freezer compartment 5, and a vegetable compartment 6. Hereinafter, the ice-making compartment 3, the upper freezer compartment 4, and the lower freezer compartment 5 may be referred to as a freezer compartment 7.

[0038] The front opening of the refrigerator compartment 2 is opened and closed by the rotating refrigerator compartment doors 210a and 210b divided into left and right parts, and the front openings of the ice making compartment 3, the upper freezer compartment 4, the lower freezer compartment 5, and the vegetable compartment 6 are opened and closed by the drawer-type ice making compartment door 310, the upper freezer compartment door 410, the lower freezer compartment door 510, and the vegetable compartment door 610 respectively.

[0039] like Figure 2As shown, a refrigerator body 10 is formed by filling a foam insulation material (e.g., polyurethane foam) between an outer box 10a and an inner box 10b to separate the outside of the refrigerator 1 from the inside. In addition to the foam insulation material, vacuum insulation material 25 is installed on the top, back, bottom, and side surfaces of the refrigerator body 10 and on the lower freezer door 510. The refrigerator compartment 2 is separated from the upper freezer compartment 4 and the ice making compartment 3 by an insulating partition wall 28, and the lower freezer compartment 5 is separated from the vegetable compartment 6 by an insulating partition wall 29.

[0040] In addition, the front sides of the storage compartments of the ice making compartment 3, the upper freezing compartment 4, and the lower freezing compartment 5 are provided with heat insulating partition walls 30 and heat insulating partition walls 31 (see FIG. Figure 1 ), wherein the heat-insulating partition wall 30 is used to prevent the air inside and outside the storage from circulating through the gap formed between the lower surface of the ice-making chamber door 310 and the upper freezer door 410 and the upper surface of the lower freezer door 510, and the heat-insulating partition wall 31 is used to prevent the air inside and outside the storage from circulating through the gap formed between the right side of the ice-making chamber door 310 and the left side of the upper freezer door 410. In addition, a heat-insulating partition wall 36 is rotatably installed on the inside of the storage at the right end of the refrigerator door 210a, which is used to prevent the air inside and outside the storage from circulating through the gap formed between the doors 210a and 210b when the refrigerator doors 210a and 210b are closed (refer to Figure 1 ).

[0041] Multiple upward-opening door shelves 33a, 33b, and 33c and multiple shelves 34a, 34b, 34c, and 34d are provided inside the doors 210a and 210b of the refrigerator compartment 2, dividing the refrigerator compartment into multiple storage spaces. The freezer compartment 7 and the vegetable compartment 6 have an ice-making container 301, an upper freezer container 401, a lower freezer middle container 502, a lower freezer lower container 503, an upper vegetable container 601, and a lower vegetable container 602, which are integrally drawn with the doors 310, 410, 510, and 610, respectively. The upper lower freezer container 501, located above the lower freezer compartment 5, is supported by guide rails (not shown) formed on the inner box 10b. When the lower freezer door 510 is pulled out, it does not withdraw with the lower freezer door 510 but remains within the refrigerator compartment.

[0042] The cold storage 1 has a cold storage evaporator chamber 8a (cold storage cooler chamber) at the approximate back of the cold storage room 2, and a cold storage evaporator 14a (cold storage cooler) is housed in the cold storage evaporator chamber 8a. A cold storage fan 9a is provided above the cold storage evaporator 14a. In addition, a cold storage room air supply path 11 is provided at the approximate center in the width direction of the back of the cold storage room 2, and cold storage room outlets 11a are provided on the upper part and left and right of the middle part of the cold storage room air supply path 11. The cooling air blown out from the cold storage room outlet 11a is as shown in FIG. Figure 2As shown by the arrow in the middle, the liquid flows forward above the shelf 34a and between the shelves 34a and 34b, respectively, and goes downward in the gaps between the shelves 34a, 34b, 34c and the door shelves 33a, 33b, 33c, and passes through the opening 92 (see FIG. 1 ) at the left rear of the space between the shelf 34c and the shelf 34d. Figure 3 ) and reaches the area behind the low temperature chamber 35. The airflow reaching the area behind the low temperature chamber 35 is discharged from the refrigeration chamber return ports 15a, 15b, and 15c (see FIG. Figure 3 ) returns to the evaporator chamber 8a for refrigeration. In addition, part of the air flowing in the space between the shelf 34c and the shelf 34d is returned to the refrigeration chamber from the refrigeration chamber return port 15d (see Figure 3 ) Return to the refrigeration evaporator chamber 8a.

[0043] There is a freezing evaporator chamber 8b (freezing cooler chamber) roughly at the back of the freezer compartment 7, and a freezing evaporator 14b (freezing cooler) is housed in the freezing evaporator chamber 8b. A freezing fan 9b is provided above the freezing evaporator 14b. In addition, there is a freezer compartment air supply path 12 at the back of the freezer compartment 7, and the freezer compartment air supply path 12 in front of the freezing fan 9b (second blower) (downstream side during normal operation) has a plurality of freezer compartment outlets (a first freezer compartment outlet 12a that mainly sprays cold air to the upper freezer compartment 4 or ice making compartment 3, and a second freezer compartment outlet 12b that mainly sprays cold air to the lower freezer compartment 5). There is a freezer compartment return port 17 (see FIG. 1 ) for returning the air delivered to the freezer compartment 7 in the front of the lower part of the freezing evaporator chamber 8b. Figure 2 and Figure 3). The first freezer compartment outlet 12a and the second freezer compartment outlet 12b are configured to be respectively arranged above the ice making compartment container 301, the upper freezer compartment container 401 and the lower freezer compartment upper container 501, the lower freezer compartment middle container 502, and the lower freezer compartment lower container 503 and located on one side of the freezer compartment air supply path 12, so that cold air flows into each container. In addition, the first freezer compartment outlet 12a and the second freezer compartment outlet 12b are arranged approximately evenly in the left-right direction. In this way, the stored food can be quickly cooled. The freezer compartment return port 17 arranged at the lower part of the freezer compartment 7 is formed to have a width approximately equal to the width of the freezing evaporator 14, so that the return cold air from the freezer compartment efficiently flows into the freezing evaporator 14. The air path to the vegetable compartment 6 constitutes the vegetable compartment air supply path 13, which is branched from the lower right side of the freezer compartment air supply path 12 and passes through the heat-insulating partition wall 29. The outlet of the vegetable compartment air supply passage 13, i.e., the vegetable compartment outlet 13a, is set to be substantially at the same height as the lower surface of the heat-insulating partition wall 29 on the upper right back of the vegetable compartment 6 and open downward. The vegetable compartment air supply passage 13 has a vegetable compartment damper 19 (see Figure 3 A vegetable compartment return port 18a is provided in the front lower left portion of the heat-insulating partition wall 29 between the vegetable compartment 6 and the freezer compartment 7, forming a flow path that passes through the vegetable compartment return air path 18 in the heat-insulating partition wall 29 and reaches the vegetable compartment return outflow port 18b provided in the front lower portion of the freezing evaporator compartment 8b.

[0044] In the cold storage of this embodiment, the refrigeration fan 9a is a centrifugal fan (backward blower), and the freezing fan 9b is an axial flow fan (propeller fan). The centrifugal fan has the characteristic of turning the air sucked in from the axial direction by 90 degrees and blowing it out radially. On the other hand, the axial flow fan has the characteristic of blowing the air sucked in from the axial direction out axially. Therefore, in an air path that turns the airflow sucked in from the axial direction by 90 degrees, the centrifugal fan has better installability, and in an air path that blows the airflow sucked in from the axial direction out axially, the axial flow fan has better installability. The refrigeration fan 9a needs to be installed in a manner that turns the air sucked in from the front by 90 degrees and blows it toward the cold storage room air supply path 11 above, so a backward blower as a centrifugal fan is adopted, and the freezing fan 9b needs to be installed in a manner that blows the air sucked in from the rear toward the freezer room air supply path 12 in front, so a propeller fan as an axial flow fan is adopted to form a cold storage with high space efficiency.

[0045] like Figure 2 and Figure 3As shown, refrigerator compartment temperature sensors 41, freezer compartment temperature sensors 42, and vegetable compartment temperature sensors 43 are provided on the back sides of refrigerator compartment 2, freezer compartment 7, and vegetable compartment 6, respectively, to detect the temperatures of refrigerator compartment 2, freezer compartment 7, and vegetable compartment 6. Furthermore, a refrigerator evaporator temperature sensor 40a is provided above refrigerator evaporator 14a, and a freezer evaporator temperature sensor 40b is provided above freezer evaporator 14b, respectively, to detect the temperatures of refrigerator evaporator 14a and freezer evaporator 14b. Furthermore, an outside air temperature and humidity sensor 37 is provided at the top of refrigerator compartment 1 to detect the temperature and humidity of the outside air (air outside the refrigerator). Doors 210a, 210b, 310, 410, 510, and 610 each have a magnet (not shown) for detecting the door's open or closed state. On the front surfaces of heat-insulating partition walls 28, 29, and 30, facing the magnets of each door, are magnetic sensors (not shown), or door sensors, respectively, that detect magnetic fields to determine the door's open or closed state.

[0046] Furthermore, a defrost heater 21 is provided below the freezing evaporator chamber 8b to heat the freezing evaporator 14b. Defrosted water (melted water) generated during defrosting of the freezing evaporator 14b flows into a water channel 23b located below the freezing evaporator chamber 8b, then flows through a drain port 22b and a freezing drain pipe 27b to a machine room 39 located at the lower rear (back) portion of the cold storage 1. The water is then discharged into an evaporating dish 32 located above the compressor 24 within the machine room 39.

[0047] Defrosted water generated during defrosting of the refrigerating evaporator 14a flows into the water guide groove 23a located below the refrigerating evaporator chamber 8a and is discharged to the evaporating dish 32 located above the compressor 24 via the drain port 22a and the refrigerating drain pipe 27a.

[0048] The machine room 39 houses the aforementioned compressor 24 and evaporation dish 32, as well as an external radiator 50a, which serves as a fin-tube heat exchanger, and an external fan 26. Driven by the external fan 26, air flows toward the compressor 24, external radiator 50a, and evaporation dish 32, promoting heat dissipation from the compressor 24 and external radiator 50a and improving energy efficiency. Furthermore, ventilation toward the evaporation dish 32 promotes evaporation of defrost water accumulated therein, thereby suppressing water overflow and improving reliability.

[0049] like Figure 3 As shown, the water channel 23a has a water channel heater 101 that melts frozen defrost water in the water channel 23a. Furthermore, the refrigeration drain pipe 27a has an upper drain pipe heater 102 and a lower drain pipe heater 103. These heaters, water channel heater 101, upper drain pipe heater 102, and lower drain pipe heater 103, all have lower capacities than the defrost heater 21.

[0050] Here, when the refrigeration fan 9a is driven, return air from the refrigeration compartment 2 flows downward through the refrigeration compartment return port 15b located at the upper right side of the refrigeration evaporator compartment 8a, toward the water channel 23a, heating the water channel 23a and raising its temperature. This reduces the amount of heat required by the water channel heater 101, which melts frozen defrost water in the water channel 23a, thereby improving energy efficiency.

[0051] Figure 4 The refrigerator 1 of this embodiment has: a compressor 24; an external radiator 50a as a fin-tube heat exchanger for dissipating heat of the refrigerant; and a refrigeration cycle (refrigerant circuit) of the refrigerator of this embodiment. Figure 2 、 Figure 3 ) as heat dissipation piping on the inner surface of the heat insulation partition walls 28, 29, and 30; condensation suppression piping 50c that suppresses condensation on the front edges of the heat-insulating partition walls 28, 29, and 30 (these condensation suppression piping 50c is collectively referred to as the heat dissipation mechanism); a three-way valve 52 that controls the flow of refrigerant; a refrigeration capillary tube 53a and a freezing capillary tube 53b that reduce the pressure of the refrigerant; and refrigeration evaporators 14a and 14b that absorb heat from the air within the storage compartment by exchanging heat between the refrigerant and the air within the storage compartment. Furthermore, a dryer 51 is provided upstream of the three-way valve 52 to remove moisture from the refrigeration cycle, and gas-liquid separators 54a and 54b are provided downstream of the refrigeration evaporator 14a and the freezing evaporator 14b, respectively, to prevent liquid refrigerant from flowing into the compressor 24. Furthermore, a check valve 56 is provided downstream of the gas-liquid separator 54b. These components are connected by refrigerant pipes to form a refrigeration cycle.

[0052] The three-way valve 52 is a refrigerant fluid control valve having an outflow port 52a and an outflow port 52b, including state 1 (refrigeration mode) in which the outflow port 52a is in an open state and the outflow port 52b is in a closed state, causing the refrigerant to flow toward the refrigeration capillary 53a side; state 2 (freezing mode) in which the outflow port 52a is in a closed state and the outflow port 52b is in an open state, causing the refrigerant to flow toward the freezing capillary 53b side; and state 3 (fully closed mode) in which both the outflow ports 52a and 52b are in a closed state.

[0053] When the three-way valve 52 is controlled to position 1 (refrigeration mode), the refrigerant discharged from the compressor 24 flows through the external radiator 50a, the external radiator 50b, and the condensation suppression piping 50c, dissipating heat, and then reaches the three-way valve 52 via the dryer 51. Since the three-way valve 52 is in position 1 (outlet 52a is open, outlet 52b is closed), the refrigerant then flows through the refrigeration capillary tube 53a, where its pressure is reduced. It then reaches the refrigeration evaporator 14a, where it undergoes heat exchange with the return air from the refrigeration compartment 2. The refrigerant flowing out of the refrigeration evaporator 14a passes through the gas-liquid separator 54a, flows through the contact portion 57a ​​with the refrigeration capillary tube 53a, and exchanges heat with the refrigerant flowing within the refrigeration capillary tube 53a before returning to the compressor 24.

[0054] When the three-way valve 52 is controlled to state 2 (freezing mode), the refrigerant discharged from the compressor 24 flows through the external radiator 50a, the external radiator 50b, and the condensation suppression piping 50c, dissipating heat, and then passes through the dryer 51 to reach the three-way valve 52. Since the three-way valve 52 is in state 2 (outlet 52a is closed, outlet 52b is open), the refrigerant then flows through the freezing capillary tube 53b, where it is decompressed and cooled. In the freezing evaporator 14b, the refrigerant exchanges heat with the return air from the freezer compartment 7 and the return air from the vegetable compartment 6 (when the vegetable compartment damper 19 is open). The refrigerant flowing out of the freezing evaporator 14b passes through the gas-liquid separator 54b, flows through the contact portion 57b with the freezing capillary tube 53b, and exchanges heat with the refrigerant flowing within the freezing capillary tube 53b before returning to the compressor 24.

[0055] When the three-way valve 52 is controlled to state 3 (fully closed mode), when the compressor 24 is driven, the refrigerant is not supplied from the refrigeration capillary 53a and the freezing capillary 53b, so the refrigerant in the refrigeration evaporator 14a or the freezing evaporator 14b can be recovered to the heat dissipation mechanism side.

[0056] The cold storage of this embodiment appropriately implements the operations of "refrigeration operation", "frozen vegetable operation", "freezing operation", "refrigerant recovery operation", "operation stop", "refrigeration evaporator defrosting operation", and "freezing evaporator defrosting operation" to cool each storage room in the cold storage 1. In the "refrigeration operation", the three-way valve 52 is controlled to state 1 (refrigeration mode), the compressor 24 is driven, the refrigeration fan 9a is driven, and the freezing fan 9b is stopped, thereby cooling the cold storage room 2; in the "frozen vegetable operation", the three-way valve 52 is controlled to state 2 (freezing mode), the compressor 24 is driven, the vegetable compartment damper 19 is open, the refrigeration fan 9a is driven or stopped, and the freezing fan 9b is driven, thereby cooling the freezing chamber 7 and the vegetable compartment 6; in the "freezing operation", the three-way valve 52 is controlled to state 2 (freezing mode), the compressor 24 is driven, the vegetable compartment damper 19 is closed, the refrigeration fan 9a is driven or stopped, and the freezing fan 9b is driven, thereby cooling the freezing chamber 7; in the "refrigerant recovery operation", the three-way valve 52 is controlled to state 2 (freezing mode), the compressor 24 is driven, the vegetable compartment damper 19 is closed, the refrigeration fan 9a is driven or stopped, and the freezing fan 9b is driven, thereby cooling the freezing chamber 7; In the "operation stop" mode, the three-way valve 52 is controlled to be in state 3 (fully closed mode), the compressor 24 is in the driving state, and the refrigerant in the evaporator 14a for refrigeration or the refrigerant in the evaporator 14b for freezing is recovered to the heat dissipation mechanism side; in the "operation stop" mode, the three-way valve 52 is controlled to be in state 3 (fully closed mode), the compressor 24 is in the stopped state, the refrigeration fan 9a is in the stopped state, and the freezing fan 9b is in the stopped state; in the "defrosting operation of the evaporator for refrigeration", the three-way valve 52 is controlled to be in state 2 (freezing mode) and the compressor 24 is controlled to be in the driving state, or the three-way valve 52 is controlled to be in state 3 (fully closed mode) and the compressor 24 is controlled to be in the stopped state. In the stopped state, when the refrigerant does not flow to the refrigeration evaporator 14a, the refrigeration fan 9a is driven, and the frost grown on the surface of the refrigeration evaporator 14a and the stored cold heat of the evaporator itself are used to cool the refrigeration chamber 2 and defrost the refrigeration evaporator 14a; in the "defrosting operation of the freezing evaporator", the three-way valve 52 is in state 3 (fully closed mode) and the compressor 24 is stopped, the refrigeration fan 9a is driven or stopped, the freezing fan 9b is stopped, and the defrost heater 21 is powered on, thereby defrosting the freezing evaporator 14b.

[0057] Although not shown, a control circuit board (control unit) equipped with a CPU, memory such as ROM and RAM, and an interface circuit is located in the mechanical compartment 39 of the cold storage 1. The control circuit board is connected to the refrigerator compartment temperature sensor 41, the freezer compartment temperature sensor 42, the vegetable compartment temperature sensor 43, the refrigeration evaporator temperature sensor 40a, the freezing evaporator temperature sensor 40b, and the door sensor. Based on the output values ​​of these sensors, temperature settings, and a program pre-recorded in the ROM, the CPU controls the on / off and speed control of the compressor 24, the refrigeration fan 9a, and the freezing fan 9b, and controls the defrost heater 21, the gutter heater 101, the drain pipe upper heater 102, the drain pipe lower heater 103, and the three-way valve 52 described later.

[0058] <Structure of Containers Stored in the Lower Freezer>

[0059] like Figure 5 As shown, the lower freezer compartment lower container 503 is supported by a pair of left and right iron frames 520 fixed to the inner surface of the lower freezer compartment door 510. The lower freezer compartment middle container 502 is placed on the lower freezer compartment lower container 503, supported by a pair of left and right legs 502b and 502c at the front and rear. The front legs 502b of the lower freezer compartment middle container 502 engage with recesses 503b formed on the upper surface of the outer wall of the lower freezer compartment lower container 503. As a result, when the lower freezer compartment door 510 is pulled out, the lower freezer compartment middle container 502 is also pulled out along with the lower freezer compartment lower container 503 supported by the frames 520. Furthermore, to prevent deformation, the frames 520 have a connecting member 522 at the rear of the lower freezer compartment lower container 503 that connects the left and right frames 520. In addition, a bearing 521 is provided at the lower rear edge of the frame 520 for smooth pulling and drawing operations. In addition, similarly to the lower container 503 of the lower freezer compartment, the ice making compartment container 301 and the upper freezer compartment container 401 are supported by the frame fixed to the ice making compartment door 310 and the upper freezer compartment door 410, and are pulled and drawn together with the ice making compartment door 310 and the upper freezer compartment door 410.

[0060] <(Normal) Freezing Operation>

[0061] Next, the flow of air in the freezing compartment during the freezing operation will be described. Figure 6 It will Figure 2The enlarged cross-sectional view near the freezer compartment shows the flow of air during normal freezing operation. The freezer compartment has a first freezer compartment outlet 12a and a second freezer compartment outlet 12b as first openings located above the opening of the lower freezer compartment lower container 503 (the upper end of the side surface of the lower freezer compartment lower container 503), and a freezer compartment return port 17 as a second opening located below the opening of the lower freezer compartment lower container 503. In addition, a first air duct connecting the first opening and the freezing evaporator 14b and a second air duct connecting the second opening and the freezing evaporator 14b are formed in the freezing evaporator chamber 8b. The second opening is connected to the lower side of the freezing evaporator 14b.

[0062] During the freezing operation, as described above, the compressor 24 and the freezing fan 9b are driven. As a result, the air that advances from the lower side of the freezing evaporator 14b to the upper side and is cooled is supplied from the first opening into the freezing chamber through the first air passage (see FIG. Figure 6 Thin solid arrows), such as Figure 6 After flowing from top to bottom as shown by the thick arrow, it returns to the freezing evaporator 14b through the second air path from the second opening (refer to Figure 6 In this embodiment, the method of reducing frost on the frozen food stored in the lower container 503 of the lower freezer compartment is described. However, if the vertical relationship with the opening of the container is maintained, frost can be similarly reduced on the other containers 401, 501, and 502.

[0063] [Example 1]

[0064] Next, the freezing operation in Example 1 will be described. In Example 1, in addition to the above-mentioned freezing operation (normal freezing operation), a container cooling freezing operation is also performed.

[0065] <Container Cooling and Freezing Operation>

[0066] Figure 7 It will Figure 2 The enlarged cross-sectional view near the freezer compartment shows the flow of air during the container cooling and freezing operation. During the container cooling and freezing operation, the compressor 24 and the freezing fan 9b are both driven, but the rotation direction of the freezing fan 9b is opposite to that during the normal freezing operation. Therefore, during the container cooling and freezing operation, the air that flows from the upper side to the lower side of the freezing evaporator 14b and is cooled is supplied to the freezer compartment through the second air duct and from the second opening (see Figure 7 Thin solid arrows), such as Figure 7 After flowing from bottom to top as shown by the thick arrow, it returns to the upper side of the freezing evaporator 14b through the first air duct from the first opening (refer to Figure 7(The thin dotted arrow). During the container cooling and freezing operation, the second air path becomes high pressure due to the reversal of the freezing fan 9b, so that cold air can be easily sent out from openings other than the second opening connected to the second air path. In this embodiment, the vegetable compartment return port 18b and the vegetable compartment outlet 13a are provided in the second air path as openings other than the second opening, so that unexpected flow of cold air into the vegetable compartment 6 may become a problem. Therefore, during the container cooling and freezing operation, backflow can also be suppressed by closing the vegetable compartment damper 19. In addition, this unexpected inflow may also become a problem in the case where the second air path is not provided with both an outlet and a return port for a storage compartment other than the freezer compartment, but only one of them. By providing a damper at the opening connected to the second air path and closing the damper during the container cooling and freezing operation, it is possible to effectively suppress the flow of cold air into the storage compartment connected to the opening.

[0067] Here, focusing on the lower container 503 of the lower freezer compartment, the cooling effect of the container is described. First, the position of the second freezer compartment outlet 12b located at the bottom of the first opening is higher than the upper end of the rear wall of the lower container 503 of the lower freezer compartment. Therefore, during normal freezing operation, even if cold air is ejected from the second freezer compartment outlet 12b, the effect of cooling the lower container 503 of the lower freezer compartment itself is low. On the other hand, the freezer compartment return port 17, which is the second opening, sends air to the lower side of the bottom surface of the lower container 503 of the lower freezer compartment when ejecting cold air. The second opening can be configured with one or more than two, but all are located lower than the upper end of the rear wall of the lower container 503 of the lower freezer compartment. It is preferred that at least a portion of the freezer compartment return port 17 is located lower than the bottom surface of the lower container 503 of the lower freezer compartment. Therefore, during the container cooling and freezing operation, the cold air ejected from the freezer compartment return port 17 can efficiently cool the bottom surface of the lower container 503 in the lower freezer compartment, and the food located above the bottom surface can also be efficiently cooled.

[0068] As described above, the container cooling and freezing operation (second cooling operation) primarily cools the bottom surface of the container, effectively cooling the bottom surface. However, compared to the normal freezing operation (first cooling operation), which primarily cools the air within the storage space, the container cooling and freezing operation takes time to cool the entire food in the freezer compartment, resulting in lower energy efficiency. Therefore, in Example 1, the container cooling and freezing operation is combined with the normal freezing operation, and in the stable state or other conditions described below, the normal freezing operation is extended compared to the container cooling and freezing operation.

[0069] In addition, the refrigeration fan 9b is designed so that the direction of rotation during normal refrigeration operation is forward, and it can efficiently supply air with less wind path loss during forward rotation. On the other hand, the direction of rotation during container cooling and refrigeration operation is reverse. During reverse rotation, the refrigeration evaporator 14b is located on the downstream side of the refrigeration fan 9b, so the swirling air collides with the fins (not shown) of the refrigeration evaporator 14b, resulting in a low air supply efficiency due to wind path loss. Therefore, for example, it is preferable to provide a wind deflector (rectifier) ​​between the refrigeration fan 9b and the refrigeration evaporator 14b to guide the air ejected from the refrigeration fan 9b to the fins of the refrigeration evaporator 14b to recover the swirling component. In addition, the flow rate of the refrigeration fan 9b is easily reduced when it is reversed compared to when it is in forward rotation, so the rotation speed can also be increased compared to when it is in forward rotation.

[0070] Furthermore, during the container cooling and freezing operation described above, the direction of rotation of the freezing fan 9b is reversed from that during normal freezing operation, and the flow of air circulating within the freezer compartment is reversed. However, other methods may be used as long as they can effectively cool the container. For example, additional air paths other than the first and second air paths described above may be added to enable switching between discharge and suction (return) of the first and second openings. Figure 18A and Figure 18B This is a schematic diagram of the air duct of a refrigerator in which the circulation direction of the cold air in the freezer compartment is switched by controlling the damper provided in the air duct instead of switching the rotation direction of the freezing fan 9b. Figure 18A This is a schematic diagram of the first wind path. Figure 18B This is a schematic diagram of the second air duct.

[0071] exist Figure 18A In the freezer compartment, the exhaust side of the freezing fan 9b is connected to the first opening 12a and the second opening 17b. A first exhaust damper 70a that can be opened and closed is disposed between the exhaust side of the freezing fan 9b and the first opening 12a, and a second exhaust damper 70b that can be opened and closed is disposed between the exhaust side of the freezing fan 9b and the second opening 17b. In addition, the return side of the freezing fan 9b is connected to the first opening 12b and the second opening 17a. A first return damper 71b that can be opened and closed is disposed between the return side of the freezing fan 9b and the first opening 12b, and a second return damper 71a that can be opened and closed is disposed between the return side of the freezing fan 9b and the second opening 17a. Normal cooling operation can be implemented by opening the first exhaust damper 70a and the second return damper 71a, and closing the second exhaust damper 70b and the first return damper 71b. Furthermore, by closing the first exhaust damper 70a and the second return damper 71a and opening the second exhaust damper 70b and the first return damper 71b, the container cooling and freezing operation can be performed.

[0072] exist Figure 18BIn the freezer compartment, the exhaust side of the refrigeration fan 9b is connected to the first opening 12a and the second opening 17a. An openable and closable first exhaust damper 70a is located between the exhaust side of the refrigeration fan 9b and the first opening 12a. Furthermore, the return side of the refrigeration fan 9b is connected to the second opening 17b. Opening the first exhaust damper 70a enables normal freezing operation. Closing it enables container cooling freezing operation.

[0073] In addition, a cooling method based on natural convection is also considered. For example, in the container cooling and freezing operation, the three-way valve 52 is controlled to state 2 (freezing mode), the compressor 24 is driven, and the freezing evaporator 14b is kept at a low temperature. At this time, by stopping the freezing fan 9b, the air that has become low temperature after heat exchange with the freezing evaporator 14b flows into the freezing chamber from the freezing chamber return port 17 and returns to the freezing evaporator chamber 8b through the second freezing chamber outlet 12b. This can produce a temperature close to Figure 7 The air flow shown is capable of cooling the container.

[0074] <Operation Control in Example 1>

[0075] Next, refer to Figures 8 to 10 The operation control of the refrigerator in the first embodiment will be described. Figure 8 This is a graph showing the temperature change in the freezer compartment in Example 1. Figure 8 The temperature in the graph represents the detection temperature of the freezing chamber temperature sensor 42.

[0076] Operation immediately after closing the lower freezer door

[0077] Figure 9 This is a flowchart showing the control immediately after the lower freezer compartment door is closed in the first embodiment.

[0078] First, when the freezer door, i.e., the lower freezer door 510, is closed and the door sensor detects that the lower freezer door 510 is in a closed state, the control unit drives the compressor 24 at high speed, causing the refrigeration fan 9b to rotate in the reverse direction at a rotation speed Na, and starts the container cooling and freezing operation (second cooling operation) (step S101). Next, the control unit determines whether a specified time ta has passed since the start of the container cooling and freezing operation (step S102). In step S102, if it is determined that the specified time ta has passed, the control unit causes the refrigeration fan 9b to rotate in the forward direction at a rotation speed Nb, and starts the normal freezing operation (first cooling operation) (step S103). In addition, as described above, it is easier to obtain a high flow rate when the refrigeration fan 9b rotates forward than when it rotates reversely, so the absolute value of the rotation speed Nb can be lower than the absolute value of the rotation speed Na. Next, the control unit determines whether a specified time tb has passed since the start of the normal freezing operation (step S104). In step S104, when it is determined that the prescribed time tb has passed, the control unit stops the freezing fan 9b (step S105. Fan stops). In this case, the compressor can be stopped or driven to perform a refrigeration operation to cool the refrigerator compartment. The compressor can also be stopped when only the prescribed time tb has passed. When the temperature detected by the refrigerator compartment temperature sensor 41 becomes above the prescribed temperature Ta after the prescribed time tb has passed, or when the temperature becomes above the prescribed temperature Ta even before the prescribed time tb has passed, the refrigeration operation is performed until the temperature detected by the refrigerator compartment temperature sensor 41 becomes below the prescribed temperature Tb. Here, Ta>Tb. In addition, preferably, ta<tb.

[0079] By stopping the freezing fan 9b and stopping the compressor or performing refrigeration operation as needed, the low temperature state below the freezing compartment can be maintained by natural convection in the freezing compartment and energy consumption can be reduced. That is, the temperature distribution in the freezing compartment is intentionally unbalanced by utilizing natural convection to maintain the low temperature below the freezing compartment.

[0080] Afterwards, the control unit determines whether a prescribed time tc has passed since the freezing fan 9b stopped (step S106). In step S106, if it is determined that the prescribed time tc has passed, the control unit determines whether the detection temperature of the freezing chamber temperature sensor 42 has become below the prescribed temperature Tc described later (step S107). If the detected temperature is higher than the prescribed temperature Tc, the control unit returns to step S101 and restarts the container cooling and freezing operation. Thereafter, the same processing as steps S102 to S106 is performed, and such processing is repeated until the detection temperature of the freezing chamber temperature sensor 42 becomes below the prescribed temperature Tc in step S107. If it is determined that the detected temperature is below the prescribed temperature Tc in step S107, the control unit waits until the detected temperature becomes above the prescribed temperature Td higher than Tc (step S108), and then transfers to step S101 again to restart the container cooling and freezing operation.

[0081] Operation of the freezer compartment in a stable state

[0082] Figure 10 This is a flowchart showing the control when the freezer compartment is in a stable state in Example 1. Here, the freezer compartment being in a stable state means a state in which the fluctuation range of the temperature detected by the freezer compartment temperature sensor 42 is within a predetermined range (between a predetermined temperature Tc and a predetermined temperature Td) by repeatedly driving and stopping the compressor 24 while all the doors 210, 310, 410, 510, and 610 of the cold storage remain closed.

[0083] First, during the normal freezing operation, the control unit determines whether the temperature detected by the freezing chamber temperature sensor 42 is below the specified temperature Tc (step S201). If it is determined that the temperature detected by the freezing chamber temperature sensor 42 is below the specified temperature Tc, the control unit stops the freezing fan 9b (step S202). At this time, if, for example, the temperature detected by the refrigerating chamber temperature sensor 41 is above the specified temperature Ta, the control unit controls the rotation speed of the compressor 24 to a low speed and stops the freezing fan 9b to perform the refrigeration operation. If the detected temperature is less than the specified temperature Ta and more than the specified time has passed since the last defrost operation, the compressor 24 is stopped, the freezing fan 9b is stopped, and the freezing evaporator defrost operation is performed. If the detected temperature is less than the specified temperature Ta and the specified time has not passed since the last defrost operation, the compressor 24 is stopped and the freezing fan 9b is stopped.

[0084] The control unit then determines whether the temperature detected by the freezer compartment temperature sensor 42 is above the predetermined temperature Td (step S203). If the temperature detected by the freezer compartment temperature sensor 42 is above the predetermined temperature Td, the control unit drives the compressor 24 at a high speed and rotates the refrigeration fan 9b in the reverse direction at a rotation speed Na, thereby starting the container cooling and freezing operation (step S204). However, if the refrigeration evaporator defrosting operation is being performed in step S202, this can be substituted for the normal freezing operation.

[0085] Next, the control unit determines whether a predetermined time tc has elapsed since the container cooling and freezing operation began (step S205). If it is determined that the predetermined time tc has elapsed in step S205, the control unit maintains the high-speed rotation of the compressor 24 and rotates the freezing fan 9b in the forward direction at a rotation speed Nb, thereby starting the normal freezing operation (step S206). The processes of steps S201 to S206 are then repeated.

[0086] In this manner, when the freezer compartment is in a stable state, the control unit sequentially repeats the fan stop operation for stopping the freezing fan 9b to allow natural convection of air in the freezer compartment, the container cooling and freezing operation, and the normal freezing operation.

[0087] <Frosting of Food in Comparative Example>

[0088] As a comparative example, the frost formation of food when the container cooling and freezing operation is not performed and only the normal freezing operation is performed will be described. The temperature of the frozen food is determined by the heat transfer caused by the heat conduction from the air in the packaging bag and the heat conduction from the container. When the freezing operation is not performed and the freezing fan is stopped, the air inside the freezer moves downward due to natural convection, causing the relatively low temperature air inside the freezer to move downward, resulting in a temperature distribution inside the freezer with a low temperature on the lower side. In this state, when the normal freezing operation is started, Figure 6 The air flows as shown by the thick arrows in the figure, so the relatively hot air on the upper side moves downward and heats the containers in the freezer compartment as it flows into the freezing evaporator compartment 8b through the freezer compartment return port 17. Therefore, the food relatively below the container in the freezer compartment (especially the food placed on the bottom surface of the lower container 503 in the lower freezer compartment) is affected by the increase in container temperature due to heat conduction from the above-mentioned container, and is therefore easily heated up after the freezing operation starts.

[0089] Figure 11This graph shows the temperature changes (steady state) of food and surrounding air in a comparative example. Here, frozen food packaged in a packaging bag is stored in lower container 503 of the lower freezer compartment, and the freezer compartment is in a steady state. The frozen food temperature (dashed line) is the temperature of the frozen food surface, and the surrounding air temperature (solid line) is the temperature of the air inside the packaging bag. The temperature of lower container 503 of the lower freezer compartment is represented by the dotted line.

[0090] First, if Figure 11 As shown in FIG. 1 , the ambient air temperature drops immediately after the normal refrigeration operation starts. This is mainly because, upon starting the normal refrigeration operation, cold air contacts the packaging bag, cooling the packaging bag and thereby rapidly cooling the air inside the packaging bag.

[0091] On the other hand, Figure 11 As shown, the temperature of the frozen food and the temperature of the lower container 503 in the lower freezer compartment temporarily rise immediately after the start of normal freezing operation. The main reasons for this are speculated to be as follows. The first main reason is that the temperature change of the frozen food is delayed compared to that of the air. Therefore, even after the start of normal freezing operation, the temperature rise before the start of normal freezing operation is temporarily affected. The second main reason is that after the start of normal freezing operation, as described above, the relatively high temperature air moves downward, causing the temperature of the lower container 503 in the lower freezer compartment to rise, thereby increasing the temperature of the frozen food.

[0092] Furthermore, a comparison of the frozen food temperature and the surrounding air temperature reveals that the frozen food temperature is consistently higher than the surrounding air temperature. This temperature difference facilitates the sublimation of moisture from the food surface, which then adheres to the inside of the packaging bag as frost. If this situation recurs, the frozen food will dry out.

[0093] <Effects of Example 1>

[0094] Next, the effects of Example 1, specifically, the effect of suppressing frost formation on frozen food will be described. Figure 12 This graph shows the temperature changes (steady state) of the frozen food and surrounding air in Example 1. Here, the frozen food, packaged in a packaging bag, is also stored in lower container 503 of the lower freezer compartment, and the freezer compartment is in a steady state. The frozen food temperature (dashed line) is the temperature of the food surface, and the surrounding air temperature (solid line) is the temperature of the air inside the packaging bag. The temperature of lower container 503 of the lower freezer compartment is indicated by the dotted line.

[0095] First, if Figure 12As shown by the solid line, the ambient air temperature decreases immediately after the container cooling and freezing operation begins. However, the temperature decreases more slowly than in the comparative example. This is because the container cooling and freezing operation primarily cools the walls, especially the bottom, of the lower container 503 in the lower freezer compartment. Therefore, the container cooling and freezing operation is less effective than normal freezing operation in cooling the air within the storage space of the lower container 503 in the lower freezer compartment.

[0096] On the other hand, Figure 12 As shown by the dotted lines, the temperature of the frozen food and the temperature of the lower container 503 in the lower freezer compartment decreases and does not increase after the container cooling and freezing operation begins. The main reasons for this are speculated to be as follows. The first main reason is that the container cooling and freezing operation rapidly cools the container bottom, so the frozen food is cooled primarily by heat conduction from the container. This cools the food bottom near the container bottom more quickly than the air inside the packaging bag. The second main reason is that, unlike after the start of a normal freezing operation, the air above the freezer compartment, which has reached a relatively high temperature due to natural convection when the fan stops, does not move downward after the container cooling and freezing operation begins.

[0097] Furthermore, a comparison of the frozen food temperature and the ambient air temperature reveals that the frozen food temperature remains consistently lower than the ambient air temperature. This is because, due to the low temperature of the container, the frozen food is relatively strongly affected by heat conduction from the container, not through the air inside the packaging bag. Consequently, moisture is less likely to sublime from the frozen food surface, suppressing frost formation inside the packaging bag. As a result, drying out of the frozen food is prevented, maintaining its quality.

[0098] Specifically, when the freezer compartment is in a stable state, it is more effective for the control unit to control the compressor 24 and the freezing fan 9b so that the average temperature of the entire bottom surface of the lower container 503 of the lower freezer compartment is maintained lower than the average temperature of the air within the entire storage space of the lower container 503 of the lower freezer compartment. One example of a means to achieve this goal is to first perform a container cooling and freezing operation in the period immediately after switching from fan operation (such as refrigeration operation) to freezing operation, thereby promoting the cooling of food by cooling the lower container 503 of the lower freezer compartment itself. As another example, when cooling the freezer compartment 7, the normal freezing operation described above may be omitted or substantially omitted, and only the container cooling and freezing operation may be performed. Furthermore, it is preferable to always maintain a relationship in which the container bottom temperature is lower than the air temperature within the container storage space, but temporary reversals of this temperature relationship are permitted. Therefore, as long as the time-averaged temperature of the freezer compartment in a stable state satisfies the relationship in which the container bottom temperature is lower than the air temperature within the container storage space, the aforementioned frost suppression effect can be expected.

[0099] <Variation of Example 1>

[0100] The container cooling and freezing operation of Example 1 is an operation for cooling the lower container 503 (first container) of the lower freezer compartment, which has the largest storage space among the multiple containers in the freezer compartment, particularly efficiently, but the same effect can be expected for containers that can be cooled efficiently compared to the normal freezing operation. In addition, the cooling efficiency of these containers during the container cooling and freezing operation can be improved by forming a third air path for guiding air in the front-to-back direction (from front to back) in the middle container 502 (second container) of the lower freezer compartment and the upper container 501 (third container) of the lower freezer compartment. The third air path is, for example, provided on the lower side of the bottom surface of the second container and the third container, and can be formed as a hollow cylindrical structure 60 having holes on the front and rear sides (see Figure 19 ). It is preferred that there is no opening on the bottom surface of the structure 60 that would cause the cool air to fall downwards, so as to promote Figure 7 Furthermore, the food stored in the second and third containers can be efficiently cooled by placing metal plates such as aluminum plates on the bottom surfaces of the second and third containers.

[0101] Furthermore, in addition to the aforementioned method of supplying air so that cold air can directly reach the third container, etc., for container cooling and freezing operation, a method can also be employed in which the freezing fan 9b is stopped, the three-way valve 52 is set to position 2 (freezing mode), and the compressor 24 is driven. Even with this method, the bottom surface temperature of the third container, etc. can be maintained lower than the internal air temperature of the storage space of the third container, etc., by natural convection. As a result, evaporation of moisture from the surface of the food inside the third container, etc. can be suppressed.

[0102] And, when using the above Figure 9 or Figure 10 In the operational control of Example 1 described above, the timing for switching from container cooling and freezing operation to normal freezing operation is determined based on the time since the container cooling and freezing operation began. However, other methods may be used instead. For example, a method is conceivable in which a temperature sensor is provided to directly measure the temperature of the container and the switch from container cooling and freezing operation to normal freezing operation is performed based on the temperature detected by the temperature sensor. If the container temperature rises, the container cooling and freezing operation is performed, and if it falls, the normal freezing operation is performed.

[0103] [Example 2]

[0104] As mentioned above, food temperatures tend to rise above the ambient air temperature in the period immediately after switching from fan-off (refrigeration operation, etc.) to freezing operation. In particular, when food is taken in and out with the freezer door open, relatively hot air flows into the freezer. Since normal freezing operation is primarily performed, the food temperature tends to rise above the ambient temperature. Therefore, in Example 2, the freezer's cooling capacity is gradually increased immediately after the freezer door is closed. This minimizes the time that the food temperature exceeds the ambient air temperature and prevents frosting on the food.

[0105] <Operation Control in Example 2>

[0106] Next, refer to Figures 13 and 14 The operation control of the refrigerator in the second embodiment will be described. Figure 13 This is a graph showing the temperature change in the freezer compartment immediately after the lower freezer compartment door is closed in Example 2. Figure 13 The temperature in the graph represents the temperature detected by the freezer compartment temperature sensor 42. In Example 2, the rotational speeds of the compressor 24 and the freezing fan 9b are gradually increased in three stages, thereby increasing the cooling capacity of the freezer compartment in three stages. In this embodiment, control such as the first freezing operation is initiated based on the closing detection of the door sensor that detects the opening and closing of the freezer compartment 7 door. However, control may also be initiated based on an increase in the detection value of the freezer compartment temperature sensor 42, for example, when it detects an increase to a reference threshold for starting normal freezing operation or container cooling freezing operation.

[0107] Figure 14 This is a flowchart showing the control immediately after the lower freezer compartment door is closed in the second embodiment.

[0108] First, when the door sensor detects that the lower freezer door 510 is closed (step S301), the control unit drives the compressor 24 at the first speed n1 and rotates the freezing fan 9b in the forward direction at the first speed N1, thereby starting the first freezing operation (step S302). Next, the control unit determines whether a predetermined time t1 has elapsed since the start of the first freezing operation, or whether the temperature detected by the freezer compartment temperature sensor 42 has fallen below the first predetermined temperature T1 (step S303).

[0109] In step S303, if it is determined that the predetermined time t1 has elapsed or the temperature has fallen below the first predetermined temperature T1, the control unit drives the compressor 24 at a second speed n2 higher than the first speed n1 and rotates the refrigeration fan 9b in the forward direction at a speed N2 higher than the first speed N1, thereby starting the second refrigeration operation (step S304). The control unit then determines whether the predetermined time t2 has elapsed since the start of the second refrigeration operation, or whether the temperature detected by the freezer compartment temperature sensor 42 has fallen below the second predetermined temperature T2 (step S305).

[0110] If, in step S305, it is determined that the predetermined time t2 has elapsed or the temperature has fallen below the second predetermined temperature T2, the control unit drives the compressor 24 at a third speed n3 higher than the second speed n2 and rotates the refrigeration fan 9b in the forward direction at a third speed N3 higher than the second speed N2, thereby starting the third refrigeration operation (step S306). The control unit then determines whether the predetermined time t3 has elapsed since the start of the third refrigeration operation, or whether the temperature detected by the freezer compartment temperature sensor 42 has fallen below the third predetermined temperature T3 (step S307).

[0111] In step S307, if it is determined that the predetermined time t3 has elapsed or the temperature has fallen below the third predetermined temperature T3, the control unit reduces the rotation speed of the refrigeration fan 9b or the rotation speed of the compressor 24 to reduce the cooling capacity, or stops the rotation of the refrigeration fan 9b to stop the refrigeration operation (step S308). If the temperature is below the third predetermined temperature T3, which is the end reference threshold for the normal refrigeration operation and / or the container cooling refrigeration operation, or a value below it, the refrigeration operation is preferably stopped.

[0112] In the second embodiment, the compressor 24 and the refrigeration fan 9b are both switched to high-speed rotation in three stages. However, the switching speed may be in two stages or in four or more stages. In addition, the number of switchings of the compressor 24 or the refrigeration fan 9b may be smaller than that of the other, or the rotation speed of one of the compressor 24 and the refrigeration fan 9b may be constant without switching.

[0113] <Frosting of Food in Comparative Example>

[0114] As a comparative example, the following describes frost formation on food when the compressor and the freezing fan are driven at a high speed (the third rotation speed described above) immediately after the lower freezer compartment door is closed. Figure 15 Graph showing the temperature changes of food and ambient air in a comparative example (immediately after the door is closed). The food temperature (dashed line) is the temperature of the food surface, and the ambient air temperature (solid line) is the temperature of the air inside the packaging bag.

[0115] like Figure 15As shown, both the ambient air and the food experience a temperature rise when the door is opened and closed, with the ambient air temperature being slightly higher. However, the ambient air temperature drops faster after the door is closed. This is because the air temperature changes more rapidly than the food. As a result, after the door is closed, the ambient air temperature drops below that of the food for a relatively short period of time. This prolonged state increases the amount of water evaporating from the food surface, and the amount of frost deposited on the inside of the packaging bag also increases.

[0116] <Effects of Example 2>

[0117] Next, the effects of Example 2, particularly the effect of suppressing frost formation on food, will be described. Figure 16 This is a graph showing the temperature changes of the food and the surrounding air (immediately after the door is closed) in Example 2. Here, the food temperature (dashed line) is the temperature of the food surface, and the surrounding air temperature (solid line) is the temperature of the air inside the packaging bag.

[0118] like Figure 16 As shown, similar to the Comparative Example, both the ambient air and the food experience a temperature rise when the door is opened and closed. During this time, the ambient air temperature is slightly higher, and the ambient air temperature drops more rapidly after the door is closed. However, in Example 2, the temperature drop of both the ambient air and the food is slower than in the Comparative Example. As a result, it takes a longer time after the door is closed for the ambient air temperature to fall below that of the food, allowing moisture to evaporate easily from the food surface. Consequently, compared to the Comparative Example, the amount of moisture evaporating from the food is reduced, and the amount of frost deposited on the inside of the packaging bag is also reduced.

[0119] Furthermore, according to Example 2, effects other than the effect of suppressing frost formation on food can also be expected. For example, in Example 2, since the initial cooling capacity is weaker than that of the comparative example, the freezing operation time is longer than that of the comparative example. However, since the initial rotation speeds of the compressor 24 and the freezing fan 9b can be lower, the overall energy consumption can be lower than that of the comparative example.

[0120] <Variation of Example 2>

[0121] In the operational control of the second embodiment, the cooling capacity of the freezer compartment is enhanced stepwise in three stages. However, this may include a state where no cooling capacity is applied during the process or a state where the cooling capacity is weakened compared to the previous state. Figure 17 This is a graph showing the temperature change in the freezer compartment immediately after the lower freezer compartment door is closed in a modified example of Example 2. Figure 17 The temperature in the graph represents the detection temperature of the freezing chamber temperature sensor 42.

[0122] In this modification, the refrigeration fan 9b is driven during the second refrigeration operation, but the compressor 24 is stopped. Therefore, the refrigeration operation time is longer than that of Example 2, but the energy consumption of the compressor 24 can be greatly reduced, so the overall energy consumption can be reduced compared to Example 2.

[0123] Thus, from the perspective of ensuring that the temperature of the frozen food does not drop too slowly compared to the temperature of the surrounding air, the surrounding air temperature may be maintained at a high level until the frozen food temperature reaches approximately the target temperature (Tc), for example, until it reaches a temperature 5°C higher than Tc, preferably until it reaches a temperature 3°C higher than Tc. As another modification, the cooling capacity may be alternating between high and low starting from the initial cooling capacity, for example, increasing the cooling capacity one or two or more times and then immediately decreasing it one or two or more times.

[0124] <Other embodiments>

[0125] The above are examples, but the present invention is not limited to these examples and encompasses various variations. For example, while the above examples each utilize two evaporators (coolers), a single evaporator (cooler) may be sufficient. Furthermore, in the above examples, the containers stored in the lower freezer compartment are three-layer containers: an upper container, a middle container, and a lower container. However, a single container may be sufficient, or a single container.

[0126] The present invention includes the following technical ideas.

[0127] [Note 1]

[0128] A cold storage, comprising:

[0129] Refrigeration cycle including compressor and cooler;

[0130] a cooler chamber for accommodating the cooler;

[0131] a freezer compartment with an opening at the front;

[0132] a freezer door for opening and closing the opening;

[0133] a door sensor for detecting an open / closed state of the freezer compartment door or a temperature sensor disposed within the freezer compartment; and

[0134] A control unit controls the freezing chamber so as to gradually increase the cooling capacity of the freezing chamber after the door sensor detects that the freezing chamber door is closed or after the detection value of the temperature sensor increases.

[0135] [Note 2]

[0136] The cold storage according to Supplementary Note 1, further comprising:

[0137] a refrigeration fan for sending air cooled by the cooler to the freezing chamber; and

[0138] the door sensor and a temperature sensor detecting the temperature inside the freezer,

[0139] When the door sensor detects that the freezer compartment door is closed or the detection value of the temperature sensor increases, the control unit drives the freezing fan at a first rotation speed, and then

[0140] When the temperature sensor detects that the temperature inside the freezing compartment has dropped to a predetermined temperature, the control unit drives the freezing fan at a second rotation speed higher than the first rotation speed.

[0141] [Note 3]

[0142] The cold storage according to Supplementary Note 1 is characterized in that

[0143] The device further comprises a refrigeration fan for conveying the air cooled by the cooler to the refrigeration chamber.

[0144] When the door sensor detects that the freezer compartment door is closed or the detection value of the temperature sensor increases, the control unit drives the freezing fan at a first rotation speed, and then

[0145] After a predetermined time has elapsed, the control unit drives the refrigeration fan at a second rotation speed higher than the first rotation speed.

[0146] [Note 4]

[0147] The refrigerator according to Supplementary Note 1 is characterized in that:

[0148] It also has the door sensor and a temperature sensor for detecting the temperature inside the freezer.

[0149] When the door sensor detects that the freezer compartment door is closed or the detection value of the temperature sensor increases, the control unit drives the compressor at a first rotation speed, and then

[0150] When the temperature sensor detects that the temperature inside the freezing chamber has dropped to a predetermined temperature, the control unit drives the compressor at a second rotation speed higher than the first rotation speed.

[0151] [Note 5]

[0152] The refrigerator according to Supplementary Note 1 is characterized in that:

[0153] When the door sensor detects that the freezer compartment door is closed or the detection value of the temperature sensor increases, the control unit drives the compressor at a first rotation speed, and then

[0154] After a predetermined time has elapsed, the controller drives the compressor at a second rotation speed higher than the first rotation speed.

[0155] [Note 6]

[0156] The refrigerator according to Supplementary Note 1 is characterized in that:

[0157] The device further comprises a refrigeration fan for conveying the air cooled by the cooler to the refrigeration chamber.

[0158] The control unit controls the rotation speeds of the freezing fan and the compressor to gradually increase when the door sensor detects that the freezer compartment door is closed or when the detection value of the temperature sensor increases.

[0159] [Note 7]

[0160] The refrigerator according to Supplementary Note 6 is characterized in that:

[0161] The process in which the rotational speeds of the refrigeration fan and the compressor gradually increase includes a state in which the refrigeration fan is driven and the compressor is stopped.

Claims

1. A cold storage, characterized in that: include: Refrigeration cycle including compressor and cooler; a cooler chamber for accommodating the cooler; a freezer compartment for storing the first container and having an opening at the front; a freezer compartment door capable of opening and closing the freezer compartment opening; and a refrigeration fan for sending the air cooled by the cooler to the freezing chamber, Wherein, in a stable state, the time-averaged temperature of the bottom surface of the first container is lower than the time-averaged temperature of the air in the storage space of the first container.

2. The refrigerator according to claim 1, wherein: In the stable state, repeatedly execute: a first cooling operation of delivering cold air into the storage space of the first container; a second cooling operation of sending cold air to the side, below the side, or bottom of the first container; and The fan for stopping the freezing fan is stopped.

3. The refrigerator according to claim 1 or 2, characterized in that: Also includes: a first air passage connecting a first opening of the freezer compartment with the cooler compartment; and a second air passage connecting the second opening of the freezer compartment to the cooler compartment, The first opening is configured to include a range above the opening of the first container. The second opening is located below the opening of the first container, and the rotation direction of the refrigeration fan is opposite in the first cooling operation in which cold air is supplied to the storage space of the first container and in the second cooling operation in which cold air is supplied to the side, below the side, or bottom of the first container. During the first cooling operation, the air cooled by the cooler is supplied to the freezing compartment from the first opening through the first air passage. During the second cooling operation, the air cooled by the cooler is supplied to the freezing compartment from the second opening through the second air passage.

4. The refrigerator according to claim 3, wherein: During the second cooling operation, the refrigeration fan rotates at a higher rotation speed than during the first cooling operation.

5. The refrigerator according to claim 3, wherein: include: Other storage rooms for storing food at a temperature range different from that of the freezing room; another air passage connecting the other storage chamber to the first air passage; and a damper disposed in the other air passage, The damper is closed during the second cooling operation.

6. The refrigerator according to claim 1 or 2, characterized in that: include: a first opening and a second opening communicating with the exhaust side of the refrigeration fan; the second opening communicating with the return side of the refrigeration fan; and One or more dampers are switched open and closed between a first cooling operation for delivering cold air into the storage space of the first container and a second cooling operation for delivering cold air to the side, below the side, or bottom of the first container. In the case of the first cooling operation and the case of the second cooling operation, the rotation direction of the refrigeration fan is the same. During the first cooling operation, at least the air cooled by the cooler is supplied to the freezing compartment from the first opening communicating with the exhaust side of the freezing fan. During the second cooling operation, the air cooled by the cooler is supplied to the freezing compartment from the second opening communicating with the exhaust side of the freezing fan.

7. The refrigerator according to claim 1 or 2, characterized in that: After stopping the refrigeration fan, a second cooling operation of sending cool air to the side, lower side, or bottom of the first container is performed before the first cooling operation of sending cool air to the storage space of the first container.

8. The refrigerator according to claim 1 or 2, characterized in that: including a door sensor for detecting the opening and closing of the freezer door, When the freezer compartment is cooled after the door sensor detects closing, a second cooling operation of delivering cold air to the side, lower side, or bottom of the first container is performed before the first cooling operation of delivering cold air to the storage space of the first container.

9. The refrigerator according to claim 1 or 2, characterized in that: The duration of the first cooling operation for delivering cool air into the storage space of the first container is longer than the duration of the second cooling operation for delivering cool air to the side surface, the lower side surface, or the bottom surface of the first container.

10. The refrigerator according to claim 1 or 2, characterized in that: In the freezing chamber, the second container is located above the first container, The second container is formed with a third air passage that guides air in the front-rear direction.

11. The refrigerator according to claim 1 or 2, characterized in that: include: a door sensor for detecting the open / closed state of the freezer door or a temperature sensor disposed within the freezer; and A control unit controls the freezing chamber so as to gradually increase the cooling capacity of the freezing chamber after the door sensor detects that the freezing chamber door is closed or after the detection value of the temperature sensor increases.

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