Refrigerator

Abstract

To provide a refrigerator capable of suppressing the drying of frozen products to maintain the quality of the frozen products.SOLUTION: A refrigerator comprises: a refrigeration cycle including a compressor and a cooler; a cooler chamber housing the cooler; a refrigeration chamber with an opening at the front; a refrigeration chamber door that opens and closes the opening; a door sensor that detects the open / closed state of the refrigeration chamber door or a temperature sensor arranged in the refrigeration chamber; and a control unit for gradually increasing the cooling capacity of the refrigeration chamber after the door sensor detects that the refrigeration chamber door has been closed or after the detection value of the temperature sensor increases.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to a refrigerator. [Background technology]

[0002] There is known a refrigerator that changes the rotation speed of a fan that blows cool air into a storage compartment depending on the temperature inside the storage compartment. For example, Patent Document 1 discloses a technology in which the rotation speed is set to a high speed when the temperature inside the storage compartment is high and the rotation speed is set to a low speed when the temperature inside the storage compartment is low. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-153788 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed in Patent Document 1 performs rapid cooling when the temperature inside the storage compartment is high. However, in the case of frozen foods packaged in a package, while the air inside the package is cooled quickly, cooling of the food itself may be delayed. If the temperature of the food remains higher than the air inside the package for a long period of time, moisture will easily evaporate from the surface of the food, and the evaporated moisture will adhere to the inside of the package as frost. If this process is repeated, the food may dry out, affecting its quality. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, for example, the configuration described in the claims is adopted. The refrigerator of the present invention includes a plurality of means for solving the above-mentioned problems, and one example thereof is a refrigerator including a refrigeration cycle including a compressor and a cooler, a cooler chamber accommodating the cooler, a freezer chamber having an opening at the front, a freezer chamber door for opening and closing the opening, a door sensor for detecting the open / closed state of the freezer chamber door or a temperature sensor disposed in the freezer chamber, and a control unit for controlling the freezer chamber so that the cooling power of the freezer chamber gradually increases after the door sensor detects that the freezer chamber door has been closed or after the detected value of the temperature sensor increases. [Brief explanation of the drawings]

[0006] [Figure 1] Front view of a refrigerator according to an embodiment [Figure 2] A longitudinal sectional view of a refrigerator according to an embodiment. [Figure 3] FIG. 1 is a front view showing the configuration of the interior of a refrigerator according to an embodiment; [Figure 4] 1 is a diagram showing the configuration of a refrigeration cycle of a refrigerator according to an embodiment of the present invention; [Figure 5] FIG. 1 is a perspective view showing the configuration of a door and a container of a refrigerator according to an embodiment. [Figure 6] Diagram showing the air flow during normal refrigeration operation [Figure 7] Diagram showing the air flow during container cooling and freezing operation [Figure 8] Graph showing temperature changes inside the freezer in Example 1 [Figure 9] 1 is a flowchart showing the control immediately after the lower freezer door is closed in the first embodiment. [Figure 10] 1 is a flowchart showing control when the freezing compartment is in a stable state in the first embodiment. [Figure 11] Graph showing temperature changes (steady state) of food and surrounding air in a comparative example [Figure 12] Graph showing temperature changes (steady state) of food and surrounding air in Example 1 [Figure 13] Graph showing temperature changes inside the freezer compartment immediately after the lower freezer compartment door is closed in Example 2. [Figure 14] 10 is a flowchart showing the control immediately after the lower freezer door is closed in the second embodiment. [Figure 15] Graph showing temperature changes of food and surrounding air (immediately after closing the door) in a comparative example [Figure 16] Graph showing temperature changes of food and surrounding air (immediately after closing the door) in Example 2 [Figure 17] Graph showing temperature changes inside the freezer compartment immediately after the lower freezer compartment door is closed in a modified example of Example 2. [Figure 18A] Schematic diagram of the first air path that uses a damper to change the circulation direction [Figure 18B] Schematic diagram of the second air path that uses a damper to change the circulation direction [Figure 19] FIG. 10 is a diagram showing the structure of a container in a modified example of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, an embodiment of the present invention will be described.

[0008] In the description of the embodiments, when considering the satisfaction of a condition where multiple conditions are connected by "or," this includes the satisfaction of either one of the multiple conditions alone or the union of the multiple conditions. For example, the statement "if condition A or condition B is satisfied, execute process C" includes the meaning of "if condition A is satisfied, execute process C," "if condition B is satisfied, execute process C," and "if either condition A or condition B, or both, are satisfied, execute process C."

[0009] In this embodiment, we consider the storage of frozen food in a package. If the temperature of the food remains higher than the air inside the package for a long period of time, moisture tends to sublimate from the surface of the food, and the sublimated moisture adheres to the inside of the package as frost. If this process is repeated, the food will dry out.

[0010] <Basic configuration of refrigerator> First, the basic configuration of a refrigerator according to this embodiment will be described with reference to Fig. 1 to Fig. 4. Fig. 1 is a front view of the refrigerator according to this embodiment, Fig. 2 is a cross-sectional view taken along line AA in Fig. 1, Fig. 3 is a cross-sectional view taken along line BB in Fig. 2, and Fig. 4 is a schematic diagram showing the configuration of a refrigeration cycle of the refrigerator according to this embodiment.

[0011] As shown in Fig. 1, refrigerator body 10 of refrigerator 1 is open at the front and has storage compartments, in this order from above: refrigerator compartment 2, ice-making compartment 3 arranged side by side on the left and right, upper freezer compartment 4, lower freezer compartment 5, and vegetable compartment 6. Hereinafter, ice-making compartment 3, upper freezer compartment 4, and lower freezer compartment 5 may be collectively referred to as freezer compartment 7.

[0012] The front opening of refrigerator compartment 2 is opened and closed by rotating refrigerator compartment doors 210a and 210b, which are divided into left and right halves, and the front openings of ice making compartment 3, upper freezer compartment 4, lower freezer compartment 5, and vegetable compartment 6 are opened and closed by pull-out ice making compartment door 310, upper freezer compartment door 410, lower freezer compartment door 510, and vegetable compartment door 610, respectively.

[0013] As shown in Fig. 2, the outside and inside of refrigerator 1 are separated by refrigerator body 10, which is formed by filling foam insulation (e.g., urethane foam) between outer box 10a and inner box 10b. In addition to the foam insulation, vacuum insulation material 25 is installed on the ceiling, back, bottom, both sides, and lower freezer door 510 of refrigerator body 10. Refrigerator compartment 2 is separated from upper freezer compartment 4 and ice making compartment 3 by an insulating partition wall 28, and lower freezer compartment 5 and vegetable compartment 6 are separated by an insulating partition wall 29.

[0014] Furthermore, the front side of each of the storage compartments, ice making compartment 3, upper freezer compartment 4, and lower freezer compartment 5, is provided with heat insulating partition wall 30 to prevent air from circulating inside and outside the compartment through a gap that occurs between the bottom surfaces of ice making compartment door 310 and upper freezer compartment door 410 and the top surface of lower freezer compartment door 510, and heat insulating partition wall 31 (see FIG. 1) to prevent air from circulating inside and outside the compartment through a gap that occurs between the right side surface of ice making compartment door 310 and the left side surface of upper freezer compartment door 410. Furthermore, heat insulating partition wall 36 is rotatably attached to the inside of the compartment at the right end of refrigerator compartment door 210a to prevent air from circulating inside and outside the compartment through a gap that occurs between refrigerator compartment doors 210a and 210b when refrigerator compartment doors 210a and 210b are closed (see FIG. 1).

[0015] The interior of doors 210a and 210b of refrigerator compartment 2 is provided with multiple upwardly opening door pockets 33a, 33b, and 33c and multiple shelves 34a, 34b, 34c, and 34d, dividing the compartment into multiple storage spaces. Freezer compartment 7 and vegetable compartment 6 are equipped with ice compartment container 301, upper freezer container 401, lower freezer middle container 502, lower freezer lower container 503, upper vegetable container 601, and lower vegetable container 602, which are pulled out together with doors 310, 410, 510, and 610, respectively. Lower freezer upper container 501, which is installed at the top of lower freezer compartment 5, is supported by guide rails (not shown) molded into inner box 10b. When lower freezer door 510 is pulled out, upper container 501 remains in the compartment without being pulled out together with lower freezer door 510.

[0016] Refrigerator 1 has refrigeration evaporator chamber 8a (refrigeration cooler chamber) located approximately at the rear of refrigeration compartment 2, and refrigeration evaporator 14a (refrigeration cooler) is housed within refrigeration evaporator chamber 8a. Refrigeration fan 9a is located above refrigeration evaporator 14a. Refrigeration compartment air duct 11 is located approximately at the center of the width of the rear of refrigeration compartment 2, and refrigeration compartment outlets 11a are located on the left and right sides of the upper and middle portions of refrigeration compartment air duct 11. The cooled air blown out from refrigeration compartment outlet 11a flows forward above shelf 34a and between shelves 34a and 34b as shown by arrows in FIG. 2, flows downward through the gaps between shelves 34a, 34b, and 34c and door pockets 33a, 33b, and 33c, and reaches the rear region of low-temperature compartment 35 through opening 92 (see FIG. 3) located at the rear left of the space between shelves 34c and 34d. The air that reaches the rear region of the low-temperature compartment 35 returns to the refrigeration evaporator compartment 8a through refrigeration compartment return ports 15a, 15b, and 15c (see FIG. 3) provided on the lower front, lower left side, and lower right front of the refrigeration evaporator compartment 8a. Also, part of the air that flows through the space between shelves 34c and 34d returns to the refrigeration evaporator compartment 8a through refrigeration compartment return port 15d (see FIG. 3) provided on the right rear of the space between shelves 34c and 34d.

[0017] A freezing evaporator chamber 8b (freezing cooler chamber) is provided at approximately the rear of freezing compartment 7, and a freezing evaporator 14b (freezing cooler) is housed within freezing evaporator chamber 8b. A freezing fan 9b is provided above freezing evaporator 14b. A freezing compartment air duct 12 is provided at the rear of freezing compartment 7, and the freezing compartment air duct 12 is provided in front of (downstream during normal operation of) freezing fan 9b (second blower) with multiple freezing compartment outlets (first freezing compartment outlet 12a that mainly discharges into upper freezing compartment 4 or ice-making compartment 3, and second freezing compartment outlet 12b that mainly discharges into lower freezing compartment 5). A freezing compartment return port 17 (see FIGS. 2 and 3) is provided at the front of the lower part of freezing evaporator chamber 8b, through which air sent to freezing compartment 7 returns. First freezer compartment outlet 12a and second freezer compartment outlet 12b are located above ice-making compartment container 301, upper freezer compartment container 401, lower freezer upper container 501, lower freezer middle container 502, and lower freezer lower container 503, respectively, and on the freezer compartment air duct 12 side, allowing cold air to flow into each container. First freezer compartment outlet 12a and second freezer compartment outlet 12b are also located approximately evenly in the left-right direction, allowing stored food to be cooled quickly. Freezer compartment return port 17, located at the bottom of freezer compartment 7, is formed with a width approximately equal to the width of freezing evaporator 14, allowing cold air returning from the freezer compartment to efficiently flow into freezing evaporator 14. Vegetable compartment air duct 13, which serves as an air duct to vegetable compartment 6, branches off from the lower right of freezer compartment air duct 12 and passes through insulating partition wall 29. Crisper compartment outlet 13a, which serves as the outlet of crisper compartment air duct 13, is located at approximately the same height as the underside of heat-insulating partition wall 29 at the upper right rear of crisper compartment 6 and opens downward. Crisper compartment air duct 13 is equipped with a crisper damper 19, which is a cooling control means for crisper compartment 6 (see FIG. 3). Crisper compartment return port 18a is provided at the lower left front of heat-insulating partition wall 29 between crisper compartment 6 and freezer compartment 7, and a flow path is formed that leads via crisper compartment return air duct 18, which passes through heat-insulating partition wall 29, to crisper compartment return outlet 18b, which is located at the lower front of freezing evaporator chamber 8b.

[0018] In the refrigerator of this embodiment, the refrigeration fan 9a is a centrifugal fan (backward-facing fan), and the freezing fan 9b is an axial fan (propeller fan). A centrifugal fan has the characteristic of turning air drawn in from the axial direction by 90 degrees and blowing it out in a radial direction. On the other hand, an axial fan has the characteristic of blowing air drawn in from the axial direction in the axial direction. For this reason, a centrifugal fan is easy to install in an air duct that turns air drawn in axially by 90 degrees, while an axial fan is easy to install in an air duct that blows air drawn in axially in the axial direction. The refrigeration fan 9a is installed to draw air drawn in from the front and turn it by 90 degrees to blow it out into the refrigerator compartment air duct 11 above, so a backward-facing centrifugal fan is used. The freezing fan 9b is installed to draw air drawn in from the rear and blow it out into the freezer compartment air duct 12 at the front, so an axial propeller fan is used, resulting in a highly space-efficient refrigerator.

[0019] 2 and 3, a refrigerator compartment temperature sensor 41, a freezer compartment temperature sensor 42, and a vegetable compartment temperature sensor 43 are provided on the rear interior sides of the refrigerator compartment 2, freezer compartment 7, and vegetable compartment 6, respectively, to detect the temperatures of the refrigerator compartment 2, freezer compartment 7, and vegetable compartment 6. In addition, a refrigerator evaporator temperature sensor 40a is provided above the refrigerator evaporator 14a, and a freezer evaporator temperature sensor 40b is provided above the freezer evaporator 14b, to detect the temperatures of the refrigerator evaporator 14a and the freezer evaporator 14b. In addition, an outside air temperature and humidity sensor 37 is provided on the ceiling of the refrigerator 1 to detect the temperature and humidity of the outside air (air outside the refrigerator). Doors 210a, 210b, 310, 410, 510, and 610 are each equipped with a magnet (not shown) for detecting whether the door is open or closed, and the front surfaces of the insulating partition walls 28, 29, and 30 facing the magnets of each door are each equipped with a door sensor, which is a magnetic sensor (not shown) that determines whether the door is open or closed by detecting a magnetic field.

[0020] Further, a defrost heater 21 that heats freezing evaporator 14b is provided at the bottom of freezing evaporator chamber 8b. Defrost water (melted water) generated when freezing evaporator 14b is defrosted flows down into gutter 23b provided at the bottom of freezing evaporator chamber 8b, and reaches machine room 39 provided at the bottom rear (back side) of refrigerator 1 via drain outlet 22b and freezing drain pipe 27b, and is discharged into evaporation pan 32 above compressor 24 installed in machine room 39.

[0021] In addition, the defrosted water generated during defrosting of the refrigeration evaporator 14a flows down into the gutter 23a provided at the bottom of the refrigeration evaporator chamber 8a, and is discharged into the evaporator tray 32 provided at the top of the compressor 24 via the drain outlet 22a and the refrigeration drain pipe 27a.

[0022] The machine room 39 is equipped with the compressor 24 and evaporator pan 32, as well as an external radiator 50a, which is a fin-tube heat exchanger, and an external fan 26. Driving the external fan 26 causes air to flow through the compressor 24, external radiator 50a, and evaporator pan 32, promoting heat dissipation from the compressor 24 and external radiator 50a and improving energy-saving performance. Ventilation through the evaporator pan 32 also promotes evaporation of defrost water accumulated in the evaporator pan 32, preventing overflow and improving reliability.

[0023] As shown in Fig. 3, the gutter 23a is provided with a gutter heater 101 that melts defrosted water that has frozen in the gutter 23a. In addition, the refrigeration drain pipe 27a is provided with an upper drain pipe heater 102 and a lower drain pipe heater 103. Note that the gutter heater 101, the upper drain pipe heater 102, and the lower drain pipe heater 103 are all heaters with a lower capacity than the defrost heater 21.

[0024] When the refrigeration fan 9a is driven, the return air from the refrigeration compartment 2 flows downward toward the gutter 23a via the refrigeration compartment return port 15b provided at the upper right of the refrigeration evaporator compartment 8a, heating the gutter 23a and raising its temperature. This has the effect of reducing the amount of heat required by the gutter heater 101, which melts the defrosted water frozen in the gutter 23a, thereby improving energy-saving performance.

[0025] 4 shows a refrigeration cycle (refrigerant circuit) of a refrigerator according to this embodiment. Refrigerator 1 according to this embodiment includes compressor 24, external radiator 50a, which is a fin-tube heat exchanger that radiates heat from the refrigerant, external radiator 50b, which is a heat radiation pipe provided on the inner surface of outer casing 10a (see FIGS. 2 and 3), condensation suppression pipe 50c, which suppresses condensation on front edges of heat-insulating partition walls 28, 29, and 30 (external radiator 50a, external radiator 50b, and condensation suppression pipe 50c are collectively referred to as heat radiation means), three-way valve 52, which is a refrigerant flow control means, refrigeration capillary tube 53a and freezing capillary tube 53b, which are decompression means for decompressing the refrigerant, and refrigeration evaporator 14a and freezing evaporator 14b, which exchange heat between the refrigerant and the air inside the refrigerator to absorb heat inside the refrigerator. Furthermore, upstream of the three-way valve 52 is provided a dryer 51 that removes moisture in the refrigeration cycle, and downstream of the refrigeration evaporator 14a and downstream of the refrigeration evaporator 14b are provided gas-liquid separators 54a and 54b, respectively, that prevent liquid refrigerant from flowing into the compressor 24. Furthermore, downstream of the gas-liquid separator 54b is provided a check valve 56. These components are connected by refrigerant piping to form a refrigeration cycle.

[0026] The three-way valve 52 is a refrigerant flow control valve having an outlet 52a and an outlet 52b, and is equipped with three modes: state 1 (refrigeration mode) in which the outlet 52a is open and the outlet 52b is closed, allowing the refrigerant to flow toward the refrigeration capillary tube 53a; state 2 (freezing mode) in which the outlet 52a is closed and the outlet 52b is open, allowing the refrigerant to flow toward the freezing capillary tube 53b; and state 3 (fully closed mode) in which both the outlets 52a and 52b are closed.

[0027] When three-way valve 52 is controlled to state 1 (refrigeration mode), the refrigerant discharged from compressor 24 flows through external radiator 50a, external radiator 50b, and condensation prevention piping 50c to radiate heat, and then reaches three-way valve 52 via dryer 51. Because three-way valve 52 is in state 1 (outlet 52a is open, and outlet 52b is closed), the refrigerant then flows through refrigeration capillary tube 53a, is decompressed, and reaches refrigeration evaporator 14a, where it exchanges heat with the return air of refrigeration compartment 2. The refrigerant that has left refrigeration evaporator 14a passes through gas-liquid separator 54a and flows through contact portion 57a ​​with refrigeration capillary tube 53a, where it exchanges heat with the refrigerant flowing inside refrigeration capillary tube 53a, and then returns to compressor 24.

[0028] When three-way valve 52 is controlled to state 2 (freezing mode), refrigerant discharged from compressor 24 flows through external radiator 50a, external radiator 50b, and condensation suppression piping 50c to dissipate heat, and then reaches three-way valve 52 via dryer 51. Because three-way valve 52 is in state 2 (outlet 52a is closed and outlet 52b is open), the refrigerant then flows through freezing capillary tube 53b, where it is decompressed and cooled, and then exchanges heat with return air from freezing compartment 7 and return air from vegetable compartment 6 (when vegetable compartment damper 19 is open) in freezing evaporator 14b. The refrigerant that leaves freezing evaporator 14b passes through gas-liquid separator 54b and flows through contact portion 57b with freezing capillary tube 53b, where it exchanges heat with the refrigerant flowing through freezing capillary tube 53b, before returning to compressor 24.

[0029] When the three-way valve 52 is controlled to state 3 (fully closed mode), driving the compressor 24 results in a state in which refrigerant is not supplied from the refrigeration capillary tube 53a and the freezing capillary tube 53b, so that the refrigerant in the refrigeration evaporator 14a or the refrigerant in the freezing evaporator 14b can be recovered to the heat dissipation means side.

[0030] The refrigerator of this embodiment controls three-way valve 52 to state 1 (refrigerating mode), compressor 24 is driven, refrigerating fan 9a is driven, and freezing fan 9b is stopped, thereby cooling refrigerator compartment 2. The refrigerator of this embodiment controls three-way valve 52 to state 2 (freezing mode), compressor 24 is driven, vegetable compartment damper 19 is opened, refrigerating fan 9a is driven or stopped, and freezing fan 9b is driven, thereby cooling freezer compartment 7 and vegetable compartment 6. "Freezing operation" in which 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 to cool the freezing compartment 7; "refrigerant recovery operation" in which the three-way valve 52 is controlled to state 3 (fully closed mode), the compressor 24 is driven, and the refrigerant in the refrigeration evaporator 14a or the refrigerant in the freezing evaporator 14b is recovered to the heat dissipation means side; "Operation stop" in which the three-way valve 52 is set to state 3 (fully closed mode) to stop the compressor 24, the refrigeration fan 9a, and the freezing fan 9b; "Operation stop" in which the three-way valve 52 is controlled to state 2 (freezing mode) and the compressor 24 is driven, or the three-way valve 52 is controlled to state 3 (fully closed mode) and the compressor 24 is driven so that no refrigerant flows through the refrigeration evaporator 14a, and the refrigeration fan 9a is driven, thereby preventing the refrigerant from growing on the surface of the refrigeration evaporator 14a. Each storage compartment of the refrigerator 1 is cooled by appropriately performing the following operations: a "refrigeration evaporator defrosting operation" in which the refrigeration evaporator 14a is defrosted while cooling the refrigerator compartment 2 with frost and the cold heat stored in the evaporator itself; and a "freezing evaporator defrosting operation" in which the freezing evaporator 14b is defrosted by setting the three-way valve 52 to state 3 (fully closed mode) to stop the compressor 24, driving or stopping the refrigeration fan 9a, stopping the freezing fan 9b, and energizing the defrost heater 21.

[0031] Although not shown, a control board (control unit) equipped with a CPU, memories such as ROM and RAM, an interface circuit, etc. is disposed in machine room 39 of refrigerator 1. The control board is connected to refrigerator compartment temperature sensor 41, freezer compartment temperature sensor 42, vegetable compartment temperature sensor 43, refrigerator evaporator temperature sensor 40a, freezer evaporator temperature sensor 40b, door sensor, etc., and based on these output values ​​and temperature settings, programs pre-recorded in the ROM, etc., the CPU controls the ON / OFF and rotation speed of compressor 24, refrigerator fan 9a, and freezer fan 9b, defrost heater 21, gutter heater 101, upper drain pipe heater 102, lower drain pipe heater 103, and three-way valve 52 (described later).

[0032] <Configuration of containers housed in the lower freezer compartment> As shown in FIG. 5 , lower freezer compartment lower container 503 is supported by a pair of left and right iron frames 520 fixed to the inner surface of lower freezer compartment door 510, and lower freezer compartment middle container 502 is placed on lower freezer compartment lower container 503 so as to be supported by a pair of left and right legs 502b, 502c at the front and rear, respectively. Here, front leg 502b of lower freezer compartment middle container 502 is adapted to engage with recess 503b formed on the upper surface of the outer wall of lower freezer compartment lower container 503. As a result, when lower freezer compartment door 510 is pulled out, lower freezer compartment lower container 503 supported by frames 520 and lower freezer compartment middle container 502 are also pulled out. To prevent deformation, frame 520 is provided with connecting member 522 connecting left and right frames 520 at the rear of lower freezer compartment lower container 503. Furthermore, bearings 521 are provided at the lower rear edge of frame 520 to allow for smooth removal. Ice-making compartment container 301 and upper-level freezer compartment container 401, like lower-level freezer compartment lower container 503, are supported by frames fixed to ice-making compartment door 310 and upper-level freezer compartment door 410, respectively, and are designed to be removed together with ice-making compartment door 310 and upper-level freezer compartment door 410.

[0033] <(Normal) Refrigeration Operation> Next, the air flow within the freezer compartment during freezing operation will be described. FIG. 6 is an enlarged cross-sectional view of the freezer compartment and its vicinity in FIG. 2, showing the air flow during normal freezing operation. The freezer compartment has first freezer compartment outlet 12a and second freezer compartment outlet 12b as first openings located above the opening of lower freezer compartment lower container 503 (the upper end of the side surface of lower freezer compartment lower container 503), and freezer compartment return port 17 as a second opening located below the opening of lower freezer compartment lower container 503. A first air passage connecting the first openings to freezing evaporator 14b and a second air passage connecting the second openings to freezing evaporator 14b are formed in freezing evaporator chamber 8b. The second opening is connected to the underside of freezing evaporator 14b.

[0034] During freezing operation, as described above, compressor 24 and freezing fan 9b are driven. Then, cooled air traveling from the lower side to the upper side of freezing evaporator 14b passes through the first air passage and is supplied into the freezing compartment from the first opening (see the thin solid arrow in FIG. 6), flows from top to bottom as shown by the thick arrow in FIG. 6, and then passes through the second opening and the second air passage and returns to freezing evaporator 14b (see the thin dotted arrow in FIG. 6). In this embodiment, the reduction of frost formation on frozen food stored in lower container 503 in the lower freezer compartment will be described, but frost formation can also be similarly reduced for other containers 401, 501, and 502 as long as the vertical relationship with the openings of the containers is maintained. [Example]

[0035] Next, a description will be given of the refrigeration operation in Example 1. In Example 1, in addition to the above-mentioned refrigeration operation (normal refrigeration operation), a container cooling refrigeration operation is performed.

[0036] <Container cooling and freezing operation> FIG. 7 is an enlarged cross-sectional view of the freezer compartment and its vicinity in FIG. 2, showing the airflow during container cooling freezing operation. Even during container cooling freezing operation, the compressor 24 and freezing fan 9b are driven, but the rotation direction of freezing fan 9b is reversed from that during normal freezing operation. Therefore, during container cooling freezing operation, cooled air travels from the top to the bottom of freezing evaporator 14b, passes through the second air passage, and is supplied to the freezer compartment from the second opening (see the thin solid arrow in FIG. 7). It then flows from bottom to top as shown by the thick arrow in FIG. 7, then passes through the first opening and the first air passage, and returns to the top of freezing evaporator 14b (see the thin dotted arrow in FIG. 7). During container cooling freezing operation, the second air passage becomes highly pressurized due to the reverse rotation of freezing fan 9b, making it easier for cool air to be sent out from openings other than the second opening that communicate with the second air passage. In this embodiment, the second air passage is provided with openings other than the second opening, such as vegetable compartment return port 18b and vegetable compartment outlet port 13a, which can cause unintended inflow into vegetable compartment 6. Therefore, backflow can be suppressed by closing vegetable compartment damper 19 during container cooling / freezing operation. Note that this unintended inflow can also be a problem when only one of the outlet and return ports of a storage compartment other than the freezer compartment is provided in the second air passage, rather than both. By providing a damper in the opening communicating with the second air passage and closing it during container cooling / freezing operation, inflow into the storage compartment communicating with this opening can be effectively suppressed.

[0037] Here, the cooling effect of the container will be described, focusing on lower freezer compartment lower container 503. First, second freezer compartment outlet 12b, the lowest of the first openings, is located above the upper end of the rear wall of lower freezer compartment lower container 503. Therefore, even if cold air is discharged from second freezer compartment outlet 12b during normal freezing operation, the effect of cooling lower freezer compartment lower container 503 itself is low. On the other hand, freezer compartment return port 17, which is the second opening, sends air to the underside of the bottom surface of lower freezer compartment lower container 503 when discharging cold air. One or more second openings may be provided, but all are located below the upper end of the rear wall of lower freezer compartment lower container 503. It is preferable that at least a portion of freezer compartment return port 17 is located below the bottom surface of lower freezer compartment lower container 503. Therefore, when cold air is discharged from the freezer compartment return port 17 during container cooling and freezing operation, the bottom surface of the lower container 503 in the lower freezer compartment can be efficiently cooled, and food on the bottom surface can also be efficiently cooled.

[0038] In this way, the container cooling freezing operation (second cooling operation) mainly cools the bottom surface of the container, and can efficiently cool the bottom surface of the container. However, compared to the normal freezing operation (first cooling operation), which mainly cools the air in the storage space, the container cooling freezing operation takes longer to cool all of the food in the freezer compartment and is inferior in terms of power consumption. For this reason, in Example 1, the container cooling freezing operation and the normal freezing operation are combined, and the time of the normal freezing operation is made longer than the time of the container cooling freezing operation in the stable state or in a state other than the stable state, as described below.

[0039] The refrigeration fan 9b rotates forward during normal refrigeration operation and is designed to efficiently blow air with minimal airflow loss. On the other hand, the refrigeration fan 9b rotates reversely during container cooling refrigeration operation. Because the refrigeration evaporator 14b is located downstream of the refrigeration fan 9b, swirling air collides with the fins (not shown) of the refrigeration evaporator 14b during reverse rotation, resulting in reduced airflow loss and reduced airflow efficiency. Therefore, it is desirable to install an air deflector (blowback vane) between the refrigeration fan 9b and the refrigeration evaporator 14b to guide the air discharged from the refrigeration fan 9b toward the fins of the refrigeration evaporator 14b and recover the swirling air. Because the flow rate of the refrigeration fan 9b tends to decrease during reverse rotation compared to forward rotation, the rotation speed of the refrigeration fan 9b may be increased compared to forward rotation.

[0040] Furthermore, while the container cooling freezing operation described above involves reversing the rotation direction of freezing fan 9b compared to normal freezing operation, thereby reversing the flow of air circulating within the freezing compartment, other methods may be used as long as the container can be cooled efficiently. For example, by adding an air path other than the first and second air paths described above, it may be possible to switch between discharge and suction (return) from the first and second openings. Figures 18A and 18B are schematic diagrams of air paths in a refrigerator in which the circulation direction of cool air within the freezing compartment is switched by controlling a damper provided in the air path, instead of switching the rotation direction of freezing fan 9b. Figure 18A is a schematic diagram of the first air path, and Figure 18B is a schematic diagram of the second air path.

[0041] In the freezer compartment of Fig. 18A, the discharge side of the freezing fan 9b communicates with the first opening 12a and the second opening 17b. A first discharge damper 570a that can be opened or closed is disposed between the discharge side of the freezing fan 9b and the first opening 12a, and a second discharge damper 570b that can be opened or closed is disposed between the discharge side of the freezing fan 9b and the second opening 17b. The return side of the freezing fan 9b communicates with the first opening 12b and the second opening 17a. A first return damper 571b that can be opened or closed is disposed between the return side of the freezing fan 9b and the first opening 12b, and a second return damper 571a that can be opened or closed is disposed between the return side of the freezing fan 9b and the second opening 17a. Normal refrigeration operation can be performed by opening first discharge damper 570a and second return damper 571a and closing second discharge damper 570b and first return damper 571b. Container cooling refrigeration operation can be performed by closing first discharge damper 570a and second return damper 571a and opening second discharge damper 570b and first return damper 571b.

[0042] In the freezer compartment of FIG. 18B, the discharge side of the freezer fan 9b is in communication with the first opening 12a and the second opening 17a. A first discharge damper 570a that can be opened and closed is disposed between the discharge side of the freezer fan 9b and the first opening 12a. The return side of the freezer fan 9b is in communication with the second opening 17b. By opening the first discharge damper 570a, normal freezing operation can be performed. By closing the damper, container cooling freezing operation can be performed.

[0043] A cooling method using natural convection is also possible. For example, in container cooling / 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 set to a low temperature. At this time, the freezing fan 9b is stopped, and heat is exchanged with the freezing evaporator 14b. The cooled air flows into the freezing chamber through the freezing chamber return port 17 and returns to the freezing evaporator chamber 148b through the second freezing chamber discharge port 12b. A flow similar to that shown in FIG. 7 can be created, allowing the container to be cooled.

[0044] <Operation Control in Example 1> Next, while referring to FIGS. 8 to 10, the operation control of the refrigerator of Example 1 will be described. FIG. 8 is a graph showing the temperature change in the freezer compartment in Example 1. In the graph of FIG. 8, the temperature indicates the detected temperature of the freezer compartment temperature sensor 42.

[0045] ≪Operation immediately after the lower freezer compartment door is closed≫ FIG. 9 is a flowchart showing the control immediately after the lower freezer compartment door in Example 1 is closed.

[0046] First, when the lower freezer compartment door 510 as the freezer compartment door is closed and the door sensor detects that the lower freezer compartment door 510 is in the closed state, the control unit drives the compressor 24 at a high rotation speed while rotating the freezer fan 9b in the reverse direction at a rotation speed Na, and starts the container cooling refrigeration operation (second cooling operation) (step S101). Next, the control unit determines whether or not a predetermined time ta has elapsed since the start of the container cooling refrigeration operation (step S102). In step S102, if it is determined that the predetermined time ta has elapsed, the control unit rotates the freezer fan 9b in the forward direction at a rotation speed Nb and starts the normal refrigeration operation (first cooling operation) (step S103). As described above, since a higher flow rate is easily obtained during the forward rotation of the freezer fan 9b than during the reverse rotation, the absolute value of the rotation speed Nb may be lower than the absolute value of the rotation speed Na. Next, the control unit determines whether or not a predetermined time tb has elapsed since the start of the normal refrigeration operation (step S104). In step S104, if it is determined that the predetermined time tb has elapsed, the control unit stops the freezer fan 9b (step S105. Fan stop operation). In this case, the compressor may be stopped, or a refrigeration operation may be performed to cool the refrigerator compartment while driving it. In the case of only the elapse of the predetermined time tb, the compressor is stopped, and when the temperature detected by the refrigerator compartment temperature sensor 41 becomes equal to or higher than a predetermined temperature Ta after the elapse of the predetermined time tb, or even before the elapse if it becomes equal to or higher than the predetermined temperature Ta, refrigeration operation may be performed until the temperature detected by the refrigerator compartment temperature sensor 41 becomes equal to or lower than a predetermined temperature Tb. However, Ta > Tb. Also, it is preferable that ta < tb.

[0047] By stopping the freezing fan 9b and stopping the compressor or performing refrigeration operation as needed, it is possible to reduce power consumption while maintaining a low temperature in the lower part of the freezing compartment through natural convection in the freezing compartment. In other words, by intentionally biasing the temperature distribution in the freezing compartment through natural convection, it is possible to maintain a low temperature in the lower part of the freezing compartment.

[0048] The control unit then determines whether a predetermined time tc has elapsed since the refrigeration fan 9b was stopped (step S106). If it is determined in step S106 that the predetermined time tc has elapsed, the control unit determines whether the temperature detected by the freezer compartment temperature sensor 42 is equal to or lower than a predetermined temperature Tc (described later) (step S107). If the detected temperature is higher than the predetermined temperature Tc, the control unit returns to step S101 and starts the container cooling / freezing operation again. Thereafter, the same processes as in steps S102 to S106 are performed, and these are repeated until the temperature detected by the freezer compartment temperature sensor 42 is equal to or lower than the predetermined temperature Tc in step S107. If it is determined in step S107 that the detected temperature is equal to or lower than the predetermined temperature Tc, the control unit waits until the detected temperature is equal to or higher than a predetermined temperature Td, which is higher than Tc (step S108), and then returns to step S101 and starts the container cooling / freezing operation again.

[0049] <<Operation when the freezer compartment is in a stable state>> 10 is a flowchart showing the control when the freezer compartment is in a stable state in Example 1. The state when the freezer compartment is in a stable state refers to a state in which the fluctuation range of the temperature detected by freezer compartment temperature sensor 42 falls within a predetermined range (between predetermined temperature Tc and predetermined temperature Td) by repeatedly driving and stopping compressor 24 while all doors 210, 310, 410, 510, and 610 of the refrigerator remain closed.

[0050] First, during normal freezing operation, the control unit determines whether the temperature detected by the freezer compartment temperature sensor 42 is equal to or lower than a predetermined temperature Tc (step S201). If it is determined that the temperature detected by the freezer compartment temperature sensor 42 is equal to or lower than the predetermined temperature Tc, the control unit stops the freezer fan 9b (step S202). At this time, for example, if the temperature detected by the refrigerator compartment temperature sensor 41 is equal to or higher than a predetermined temperature Ta, the control unit performs refrigeration operation by reducing the rotation speed of the compressor 24 and stopping the freezer fan 9b. If the detected temperature is lower than the predetermined temperature Ta and a predetermined time or more has elapsed since the previous defrosting operation, the control unit stops the compressor 24 and the freezer fan 9b and performs a freezer evaporator defrosting operation. If the detected temperature is lower than the predetermined temperature Ta and the predetermined time has not elapsed since the previous defrosting operation, the control unit stops the compressor 24 and the freezer fan 9b.

[0051] Thereafter, the control unit determines whether the temperature detected by the freezer compartment temperature sensor 42 is equal to or higher than the predetermined temperature Td (step S203). If it is determined that the temperature detected by the freezer compartment temperature sensor 42 is equal to or higher than the predetermined temperature Td, the control unit drives the compressor 24 at high speed and rotates the freezer fan 9b in the reverse direction at the rotation speed Na, thereby starting the container cooling freezing operation (step S204). However, if the freezer evaporator defrosting operation was being performed in step S202, it can be replaced with the normal freezing operation.

[0052] Next, the control unit determines whether or not a predetermined time tc has elapsed since the start of the container cooling refrigeration operation (step S205). If it is determined in step S205 that the predetermined time tc has elapsed, the control unit rotates the refrigeration fan 9b in the forward direction at a rotation speed Nb while maintaining the compressor 24 at high rotation speed, thereby starting a normal refrigeration operation (step S206). Thereafter, the processes of steps S201 to S206 are repeated.

[0053] In this way, when the freezing compartment is in a stable state, the control unit repeatedly executes a fan stop operation in which the freezing fan 9b is stopped to allow natural convection of the air in the freezing compartment, a container cooling freezing operation, and a normal freezing operation in this order.

[0054] <Frost on food in comparative example> As a comparative example, we will explain the frosting of food when only normal freezing operation is performed without container cooling freezing operation. The temperature of the frozen food is determined by heat transfer from the air inside the package and heat conduction from the container. When freezing operation is not performed and the freezing fan is stopped, the air inside the freezer compartment moves relatively cooler air downward due to natural convection, resulting in a temperature distribution inside the freezer compartment with lower temperatures at the bottom. When normal freezing operation is started under these conditions, air flows as shown by the thick arrows in Figure 6, causing the relatively hot air at the top to move downward and heat the containers inside the freezer compartment as it flows into the freezing evaporator chamber 148b through the freezer compartment return port 17. Therefore, food located relatively lower in the containers inside the freezer compartment (especially food placed on the bottom of the lower freezer compartment lower container 503) are affected by the temperature rise from the containers due to heat conduction from the containers, and are therefore likely to rise in temperature immediately after the freezing operation starts.

[0055] Figure 11 is a graph showing temperature changes (steady state) of food and ambient air in a comparative example. Here, it is assumed that a packaged frozen food is stored in lower container 503 of the lower freezer compartment, and the freezer compartment is in a stable state. The frozen food temperature (dashed line) is the temperature of the surface of the frozen food, and the ambient air temperature (solid line) is the temperature of the air inside the package. The temperature of lower container 503 of the lower freezer compartment is shown by the dashed-dotted line.

[0056] First, the ambient air temperature starts to drop immediately after the start of normal freezing operation, as shown in Figure 11. The main reason for this is that when normal freezing operation starts, cold air hits the package, and as the package cools, the air inside it also cools relatively quickly.

[0057] On the other hand, as shown in Figure 11, the temperature of the frozen food and lower container 503 in the lower freezer compartment rise once immediately after the start of normal freezing operation. The main reasons for this are presumed to be as follows. The first reason is that the temperature of frozen food changes more slowly than that of air, so even after normal freezing operation starts, the effects of the temperature rise before normal freezing operation begins are felt for a while. The second reason is that immediately after normal freezing operation starts, as mentioned above, relatively high-temperature air moves downward, causing the temperature of lower container 503 in the lower freezer compartment to rise, raising the temperature of the frozen food.

[0058] Furthermore, when comparing the temperature of the frozen food with the ambient air temperature, it is clear that the temperature of the frozen food remains higher than the ambient air temperature. This temperature difference makes it easier for moisture to sublimate from the surface of the food, and the sublimated moisture adheres to the inside of the package as frost. If this process is repeated, the frozen food will dry out.

[0059] <Effects of Example 1> Next, the effects of Example 1, specifically the effect of suppressing frosting on frozen foods, will be described. Figure 12 is a graph showing the temperature changes (steady state) of the frozen food and the ambient air in Example 1. Here again, it is assumed that a packaged frozen food is stored in lower container 503 of the lower freezer compartment, and the freezer compartment is in a stable state. The frozen 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 package. The temperature of lower container 503 of the lower freezer compartment is shown by the dashed-dotted line.

[0060] First, the ambient air temperature begins to drop immediately after the start of container cooling and freezing operation, as shown by the solid line in Figure 12. However, the temperature drop is more gradual than in the comparative example. This is because the main object to be cooled in container cooling and freezing operation is the wall surface, particularly the bottom surface, of lower container 503 in the lower freezer compartment, and container cooling and freezing operation is inferior to normal freezing operation in terms of cooling the air in the storage space of lower container 503 in the lower freezer compartment.

[0061] On the other hand, the temperature of the frozen food and the lower container 503 in the lower freezer compartment have been decreasing rather than increasing since immediately after the start of container cooling freezing operation, as shown by the dashed line in Figure 12. The main reasons for this are presumed to be as follows. The first reason is that the container bottom is cooled quickly during container cooling freezing operation, so the frozen food is mainly cooled by heat conduction from the container, and the bottom of the food, which is closer to the container bottom than the air inside the package, is cooled more quickly. The second reason is that immediately after the start of container cooling freezing operation, unlike immediately after the start of normal freezing operation, the air in the upper part of the freezer compartment, which has become relatively hot due to natural convection when the fan is stopped, does not move downward.

[0062] Furthermore, when comparing the temperature of the frozen food with the ambient air temperature, it can be seen that the temperature of the frozen food remains lower than the ambient air temperature. This is because, as the container temperature drops, the frozen food is relatively more susceptible to heat conduction from the container, rather than through the air inside the package. This makes it difficult for moisture to sublimate from the surface of the frozen food, suppressing frost formation on the inside of the package. As a result, the drying of the frozen food is suppressed, making it possible to maintain the quality of the frozen food.

[0063] That is, when the freezer compartment is in a stable state, it is effective for the control unit to control the compressor 24 and the freezing fan 9b to maintain the average temperature of the entire bottom surface of the lower container 503 in the lower freezer compartment lower than the average temperature of the entire air inside the storage space of the lower container 503 in the lower freezer compartment. One example of a means for achieving this is to first perform a container cooling / freezing operation immediately after switching from fan-stop operation (e.g., refrigeration operation) to freezing operation, thereby cooling the lower container 503 in the lower freezer compartment itself and promoting the cooling of the food. As another example, when cooling the freezer compartment 7, the above-mentioned normal freezing operation may not be performed or may be performed only with the container cooling / freezing operation. Note that it is desirable to always maintain a relationship in which the temperature of the container bottom is lower than the air in the container storage space, but a temporary reversal of the temperature relationship is acceptable. Therefore, if the time-average temperature of the container bottom is lower than the air in the container storage space when the freezer compartment is in a stable state, the aforementioned frost suppression effect can be expected.

[0064] <Modification of Example 1> The container cooling / freezing operation in Example 1 was designed to efficiently cool the lower container 503 (first container) in the lower freezer compartment, which has the largest storage space among the multiple containers in the freezer compartment. However, similar effects can be expected for containers that are cooled more efficiently than in normal freezing operation. Furthermore, a third air passage that guides air in the front-to-rear direction (front to rear) may be formed in the middle container 502 (second container) in the lower freezer compartment and the upper container 501 (third container) in the lower freezer compartment to improve the cooling efficiency of these containers during container cooling / freezing operation. The third air passage can be, for example, a hollow cylindrical structure 60 provided below the bottom of the second or third container and equipped with holes on the front and rear sides (see FIG. 19 ). The bottom of the structure 60 preferably does not have any openings large enough to allow cool air to drop downward, and serves to promote the air flow indicated by the thick arrows in FIG. 7 . Furthermore, by placing a metal plate such as an aluminum plate on the bottom surface of the second container and the third container, the food stored in these containers can be cooled efficiently.

[0065] Furthermore, in addition to the above-mentioned method of blowing air so that cold air is more likely to directly hit the third container, etc., the container cooling / freezing operation may be performed by stopping the freezing fan 9b, setting the three-way valve 52 to state 2 (freezing mode), and driving the compressor 24. Even with this method, it is possible to maintain the temperature of the bottom of the third container, etc. lower than the temperature of the air inside the storage space of the third-stage container, etc., by natural convection, and as a result, it is possible to suppress evaporation of moisture from the surface of food inside the third container, etc.

[0066] Furthermore, in the operation control of Example 1 described above with reference to Figures 9 and 10, the timing to switch from container cooling refrigeration operation to normal refrigeration operation was determined based on the time since the container cooling refrigeration operation started, but other methods may be used instead. For example, a temperature sensor that directly measures the temperature of the container may be provided, and the method of switching from container cooling refrigeration operation to normal refrigeration operation may be performed based on the temperature detected by the temperature sensor. When the temperature of the container rises, container cooling refrigeration operation is performed, and when the temperature drops, normal refrigeration operation is performed. [Example]

[0067] As mentioned above, food temperatures tend to rise above the ambient air temperature immediately after switching from fan-stop operation (such as refrigeration operation) to freezing operation. In particular, after food is loaded or removed with the freezer door open, relatively hot air from outside the freezer enters the freezer, and the normal freezing operation described above is primarily performed, making it easy for food temperatures to rise above the ambient temperature. Therefore, in the second embodiment, the cooling power of the freezer is gradually increased immediately after the freezer door is closed, minimizing the time during which food temperatures exceed the ambient air temperature and preventing frost from forming on the food.

[0068] <Operation Control in Example 2> Next, operation control of a refrigerator according to a second embodiment will be described with reference to FIGS. 13 and 14. FIG. 13 is a graph showing a change in temperature inside the freezer compartment immediately after the lower freezer compartment door is closed in the second embodiment. The temperature in the graph in FIG. 13 indicates the temperature detected by the freezer compartment temperature sensor 42. In the second embodiment, the rotation speeds of the compressor 24 and the freezer fan 9b are increased in three stages, thereby increasing the cooling power of the freezer compartment in three stages. In this embodiment, control such as the first freezing operation is started in response to detection of closure of the door sensor that detects the opening and closing of the door of the freezer compartment 7. However, the control may also be started in response to detection of an increase in the detected value of the freezer compartment temperature sensor 42, for example, an increase to a threshold value that serves as a reference for starting the normal freezing operation or the container cooling freezing operation. FIG. 14 is a flowchart showing the control immediately after the lower freezer door is closed in the second embodiment.

[0069] First, when lower freezer door 510 is closed and the door sensor detects that lower freezer door 510 is in the closed state (step S301), the control unit drives compressor 24 at first rotation speed n1 and rotates freezer fan 9b in the forward direction at first rotation 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 freezer compartment temperature sensor 42 has become equal to or lower than first predetermined temperature T1 (step S303).

[0070] If it is determined in step S303 that the predetermined time t1 has elapsed or the temperature has become equal to or lower than the first predetermined temperature T1, the control unit starts the second freezing operation by driving the compressor 24 at a second rotation speed n2 higher than the first rotation speed n1 and rotating the freezing fan 9b in the forward direction at a rotation speed N2 higher than the first rotation speed N1 (step S304). Next, the control unit determines whether a predetermined time t2 has elapsed since the start of the second freezing operation or whether the temperature detected by the freezing compartment temperature sensor 42 has become equal to or lower than the second predetermined temperature T2 (step S305).

[0071] If it is determined in step S305 that the predetermined time t2 has elapsed or the temperature has become equal to or lower than the second predetermined temperature T2, the control unit starts the third freezing operation by driving the compressor 24 at a third rotation speed n3 higher than the second rotation speed n2 and rotating the freezing fan 9b in the forward direction at a third rotation speed N3 higher than the second rotation speed N2 (step S306). Next, the control unit determines whether the predetermined time t3 has elapsed since the start of the third freezing operation or whether the temperature detected by the freezing compartment temperature sensor 42 has become equal to or lower than the third predetermined temperature T3 (step S307).

[0072] If it is determined in step S307 that the predetermined time t3 has elapsed or the temperature has fallen to or below the third predetermined temperature T3, the control unit reduces the cooling power by lowering the rotation speed of the refrigeration fan 9b or the rotation speed of the compressor 24, or stops the rotation of the refrigeration fan 9b to stop the refrigeration operation (step S308). If the temperature is equal to or below the third predetermined temperature T3, which is a threshold value that serves as a criterion for terminating the normal refrigeration operation and / or the container cooling refrigeration operation, it is preferable to stop the refrigeration operation.

[0073] In the second embodiment described above, the compressor 24 and the refrigeration fan 9b are both switched to high speed rotation in three stages, but two stages or four or more stages may be used. Also, the number of times one of the compressor 24 and the refrigeration fan 9b is switched may be less than the number of times the other is switched, or the rotation speed of one of the compressor 24 and the refrigeration fan 9b may be kept constant without being switched.

[0074] <Frost on food in comparative example> As a comparative example, we will explain what happens when the compressor and freezing fan are immediately driven at high speed (the third rotation speed mentioned above) immediately after the lower freezer door is closed. Figure 15 is a graph showing the temperature changes of the food and the surrounding air (immediately after the door is closed) in the comparative example. 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 package.

[0075] As shown in Figure 15, the temperature of both the ambient air and the food rises when the door is opened and closed, and the ambient air is slightly warmer at that time. However, the temperature of the ambient air drops faster after the door is closed. This is because the temperature of air changes more quickly than that of food. As a result, the temperature of the ambient air drops below the temperature of the food in a relatively short time after the door is closed. If this condition continues for a long time, the amount of moisture evaporating from the surface of the food increases, and the amount of frost that forms on the inside of the package also increases.

[0076] <Effects of Example 2> Next, the effects of Example 2, particularly the effect of preventing frosting on food, will be described. Figure 16 is a graph showing the temperature changes of the food and the surrounding air (immediately after the door is closed) in Example 2. Here again, 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 package.

[0077] As shown in Figure 16, similar to the comparative example, the temperature of both the ambient air and the food rises when the door is opened and closed, the temperature of the ambient air is slightly higher at that time, and the temperature of the ambient air drops faster after the door is closed. However, in Example 2, the temperature drops more slowly for both the ambient air and the food than in the comparative example. As a result, after the door is closed, it takes a relatively long time for the temperature of the ambient air to fall below the temperature of the food, i.e., for moisture to easily evaporate from the food surface. Therefore, compared to the comparative example, less moisture evaporates from the food, and less frost forms on the inside of the package.

[0078] It should be noted that Example 2 can be expected to have other effects in addition to the effect of suppressing frosting on food. For example, in Example 2, the initial cooling power is weaker than in the comparative example, so the freezing operation time is longer than in the comparative example, but the initial rotation speeds of compressor 24 and freezing fan 9b can be lower, so the overall power consumption can be reduced compared to the comparative example.

[0079] <Modification of Example 2> In the operational control of the second embodiment, the cooling power of the freezer compartment is increased in three stages, but a state in which no cooling power is applied or a state in which the cooling power is weaker than the previous state may be included in between. Fig. 17 is a graph showing the temperature change inside the freezer compartment immediately after the lower freezer compartment door is closed in a modified example of the second embodiment. Note that the temperature in the graph of Fig. 17 indicates the temperature detected by the freezer compartment temperature sensor 42.

[0080] In this modification, in the second refrigeration operation, the refrigeration fan 9b is driven but the compressor 24 is stopped. Therefore, although the refrigeration operation time is longer than in the second embodiment, the power consumption in the compressor 24 can be significantly reduced, and therefore the overall power consumption can be reduced compared to the second embodiment.

[0081] In this way, to prevent the temperature of the frozen food from decreasing too slowly compared to the temperature of the ambient air, the ambient air temperature should be kept higher until the temperature of the frozen food roughly reaches the target temperature (Tc), for example, until it reaches a temperature 5°C higher than Tc, preferably a temperature 3°C higher than Tc. As another variation, the cooling power may be increased once or twice or more times from the initial cooling power, and then immediately decreased once or twice or more times, so that the cooling power is alternately increased and decreased.

[0082] <Other Examples> The above are examples, but the present invention is not limited to the above-described examples and includes various modifications. For example, in the above-described examples, two evaporators (coolers) are provided, but one evaporator (cooler) may be provided. Also, in the above-described examples, the containers housed in the lower freezer compartment are three levels, namely, an upper container, a middle container, and a lower container, but they may be two levels, namely, an upper container and a lower container, or one level.

[0083] The present invention encompasses the following technical ideas. [Appendix 1] a refrigeration cycle including a compressor and a cooler; a cooler chamber that accommodates the cooler; a freezing chamber that houses the first container and is open at the front; a freezer compartment door that can freely open and close the opening of the freezer compartment; a refrigeration fan that blows the air cooled by the cooler into the freezing compartment, A refrigerator in which, in a stable 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. [Appendix 2] In Appendix 1, In the steady state, a first cooling operation of sending cold air toward the storage space of the first container; A second cooling operation in which cold air is sent toward the side surface, the lower part of the side surface, or the bottom surface of the first container; a fan stop operation for stopping the refrigeration fan; A refrigerator characterized by repeatedly performing the above. [Appendix 3] In Appendix 1 or 2: a first air passage connecting a first opening of the freezer compartment and the cooler compartment; a second air passage connecting a second opening of the freezer compartment and the cooler compartment, the first opening being arranged to include an area 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 sent toward the storage space of the first container and in the second cooling operation in which cold air is sent toward the side surface, the lower part of the side surface, or the bottom surface of the first container; During the first cooling operation, air cooled by the cooler passes through the first air passage and is supplied to the freezing compartment from the first opening, The refrigerator, wherein, during the second cooling operation, air cooled by the cooler passes through the second air passage and is supplied to the freezer compartment from the second opening. [Appendix 4] In Appendix 3, The refrigerator, wherein, during the second cooling operation, the refrigeration fan rotates at a higher rotation speed than during the first cooling operation. [Appendix 5] In Appendix 3, Another storage compartment for storing food at a temperature range different from that of the freezer compartment; Another air passage that communicates the other storage chamber with the first air passage; a damper disposed in the other air passage, The refrigerator is characterized in that the damper is closed during the second cooling operation. [Appendix 6] In Appendix 1 or 2: the first opening and the second opening communicating with the discharge side of the refrigeration fan; the second opening communicating with the return side of the refrigeration fan; one or more dampers that are switched between opening and closing between the first cooling operation in which cold air is sent toward the storage space of the first container and the second cooling operation in which cold air is sent toward a side surface, a lower portion of the side surface, or a bottom surface of the first container; The rotation direction of the refrigeration fan is the same in the first cooling operation and the second cooling operation, During the first cooling operation, at least the air cooled by the cooler is supplied to the freezing chamber from the first opening communicating with the discharge side of the refrigeration fan, The refrigerator characterized in that, during the second cooling operation, air cooled by the cooler is supplied to the freezer compartment from the second opening communicating with the discharge side of the refrigeration fan. A refrigerator characterized by the above. [Appendix 7] In Appendix 1 or 2: A refrigerator characterized in that after the fan stop operation that stops the refrigeration fan, the second cooling operation is performed to send cold air toward the side, the lower part of the side, or the bottom of the first container before the first cooling operation that sends cold air toward the storage space of the first container. [Appendix 8] In Appendix 1 or 2: a door sensor for detecting the opening and closing of the freezer compartment door; The refrigerator is characterized in that the next cooling of the freezer compartment after the door sensor detects closure is performed by performing the second cooling operation, which sends cold air toward the side, lower part of the side, or bottom of the first container, before the first cooling operation, which sends cold air toward the storage space of the first container. [Appendix 9] In Appendix 1 or 2: A refrigerator characterized in that the duration of the first cooling operation, which sends cold air toward the storage space of the first container, is longer than the duration of the second cooling operation, which sends cold air toward the side, the lower part of the side, or the bottom of the first container. [Appendix 10] In Appendix 1 or 2: A second container is located above the first container within the freezing chamber, The refrigerator is characterized in that a third air passage that guides air in a front-to-rear direction is formed in the second container. [Explanation of symbols]

[0084] 1...refrigerator, 2...refrigerating compartment, 3...ice maker compartment, 4...upper freezer compartment, 5...lower freezer compartment, 6...vegetable compartment, 7...freezer compartment, 8a...refrigerating evaporator compartment, 8b...freezer evaporator compartment, 9a...refrigerating fan, 9b...freezer fan, 10...refrigerator body, 10a...outer box, 10b...inner box, 11...refrigerating compartment air duct, 11a...refrigerating compartment outlet, 12...freezer compartment air duct, 12a...first freezer compartment outlet, 12b...second freezer compartment outlet, 13...vegetable compartment air duct, 13a...vegetable compartment outlet, 14a...refrigerating evaporator, 14b...freezer evaporator, 15a, 15b, 15c...refrigerating compartment return port, 17...freezer compartment return port, 18...vegetable compartment return air duct, 18a...field Vegetable compartment return port, 19... vegetable compartment damper, 24... compressor, 25... vacuum insulation material, 28, 29, 30... thermal insulating 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 compartment door, 301... ice maker container, 310... ice maker 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

Claims

1. a refrigeration cycle including a compressor and a cooler; a cooler chamber that accommodates the cooler; A freezer compartment that opens to the front, a freezer compartment door that opens and closes the opening; a door sensor that detects the open / close state of the freezer compartment door or a temperature sensor that is disposed in the freezer compartment; a control unit that controls the cooling power of the freezer compartment to gradually increase after the door sensor detects that the freezer compartment door is closed or after the detection value of the temperature sensor increases; A refrigerator equipped with:

2. The refrigerator according to claim 1, a refrigeration fan that blows the air cooled by the cooler into the freezing compartment; the door sensor and the temperature sensor, When the door sensor detects that the freezer compartment door is in a closed state or the detected value of the temperature sensor is increased, the control unit drives the freezer fan at a first rotation speed, and then When the temperature sensor detects that the temperature inside the freezer compartment has dropped to a predetermined temperature, the control unit drives the freezer fan at a second rotation speed that is higher than the first rotation speed.

3. The refrigerator according to claim 1, The cooling fan further blows the air cooled by the cooler into the freezing compartment. When the door sensor detects that the freezer compartment door is in a closed state or the detected value of the temperature sensor is increased, the control unit drives the freezer fan at a first rotation speed, and then When a predetermined time has elapsed, the control unit drives the freezing fan at a second rotation speed higher than the first rotation speed.

4. The refrigerator according to claim 1, The door sensor and the temperature sensor are provided, When the door sensor detects that the freezer compartment door is in a closed state or the detection value of the temperature sensor is increased, the control unit drives the compressor at a first rotation speed, and then When the temperature sensor detects that the temperature inside the freezer compartment has dropped to a predetermined temperature, the control unit drives the compressor at a second rotation speed higher than the first rotation speed.

5. The refrigerator according to claim 1, When the door sensor detects that the freezer compartment door is in a closed state or the detection value of the temperature sensor is increased, the control unit drives the compressor at a first rotation speed, and then When a predetermined time has elapsed, the control unit drives the compressor at a second rotation speed higher than the first rotation speed.

6. The refrigerator according to claim 1, The cooling fan further blows the air cooled by the cooler into the freezing compartment. When the door sensor detects that the freezer compartment door is closed or the detected value of the temperature sensor increases, the control unit controls the freezer fan and the compressor to gradually increase their rotation speeds.

7. The refrigerator according to claim 6, The refrigerator according to claim 1, wherein the gradual increase in rotation speed of the freezing fan and the compressor includes a state in which the freezing fan is driven while the compressor is stopped.

Images