Refrigerator

Abstract

To provide a refrigerator capable of defrosting a vaporizer efficiently by using forced convection with a fan regardless of a temperature of a storage chamber in a refrigeration temperature zone, a temperature of the outside air and presence / absence of blow to the storage chamber in the refrigeration temperature zone.SOLUTION: In a refrigerator including: a storage chamber; a vaporizer to cool the storage chamber; a vaporizer chamber storing the vaporizer; a fan; a blow passage to blow from the fan to the storage chamber; a blow return passage in which air flows from the storage chamber to the vaporizer chamber; a blow control means capable of controlling the blow to the storage chamber; and a defrosting heater to heat the vaporizer, the defrosting heater being provided at an upstream part of the vaporizer chamber that is an upstream side of an air flow of the vaporizer within the vaporizer chamber, a communication part is provided through witch air can circulate in the defrosting heater, the vaporizer and the fan not via the storage chamber, and the blow control means operates a first defrosting operation for heating the vaporizer by distributing electric power to the defrosting heater while suppressing the blow to the storage chamber and operating the fan.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a refrigerator.

Background Art

[0002] Patent Document 1 describes a refrigerator provided with "a second defrosting means for performing defrosting in a state where the indoor blower is ON, the damper of the refrigerating chamber is open, the damper of the freezing chamber is closed, and the defrosting heater is ON" when the compressor stops (abstract). As an effect of the second defrosting means, it is shown that "since the return air from the refrigerator to the cooler is forced to convect by the blowing, the heat transfer efficiency between the air and the frost is good and the frost is easily melted" (paragraph 0112).

[0003] In addition, for example, a refrigerator equipped with a refrigerating cooler that cools only the storage chambers (ice making chamber, small freezing chamber, freezing chamber) in the freezing temperature range, like the refrigerator of Patent Document 2, is disclosed (paragraph 0040, FIGS. 1, 2, etc.).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the refrigerator described in Patent Document 1, for example, when the outside air is low temperature and the refrigerating chamber is likely to become low temperature, there is a concern that the temperature of the refrigerating chamber may drop during the second defrosting means and the food may be overcooled.

[0006] In addition, in the refrigerator described in Patent Document 2, when defrosting the refrigerating evaporator (refrigerating cooler), since air cannot be blown into the storage compartment in the refrigerating temperature zone, in order to force convection of the air around the refrigerating evaporator during defrosting, it is necessary to circulate the air through the storage compartment in the refrigerating temperature zone. However, when the air that has passed through the high-temperature evaporator during defrosting is blown into the storage compartment in the refrigerating temperature zone, the storage compartment in the refrigerating temperature zone will be heated. In addition, since the return air from the storage compartment in the refrigerating temperature zone flows through the refrigerating evaporator, the temperature of the air reaching the refrigerating evaporator becomes low, resulting in poor defrosting efficiency. Therefore, when the indoor blower (fan) is turned on in the state where the defrost heater is on, air circulation cannot be achieved, that is, the heat transfer efficiency between the air and the frost by forced convection cannot be improved, and the frost cannot be easily melted. The present invention has been made in view of the above-described problems, and an object thereof is to provide a refrigerator that can efficiently defrost an evaporator using forced convection by a fan regardless of the temperature of the storage compartment in the refrigerating temperature zone or the outside air, or the presence or absence of blowing air into the storage compartment in the refrigerating temperature zone.

Means for Solving the Problems

[0007] In order to solve the above-described problems, the present invention provides a refrigerator including a storage compartment, an evaporator that cools the storage compartment, an evaporator chamber that houses the evaporator, a fan, a blowing path that blows air from the fan to the storage compartment, a return air path through which air flows from the storage compartment to the evaporator chamber, a blowing control means that can control the blowing to the storage compartment, and a defrost heater that is provided in an upstream portion of the evaporator chamber on the upstream side of the air flow of the evaporator in the evaporator chamber and heats the evaporator. In the refrigerator, a communication portion through which air can circulate is provided for the defrost heater, the evaporator, and the fan without passing through the storage compartment, and a first defrost operation is performed in which the defrost heater is energized to heat the evaporator while driving the fan while suppressing the blowing to the storage compartment by the blowing control means.

Effects of the Invention

[0008] According to the present invention, it is possible to provide a refrigerator that efficiently defrosts an evaporator using forced convection by a fan regardless of the temperature of a storage chamber in the refrigerating temperature range or the outside air, or the presence or absence of blowing air into the storage chamber in the refrigerating temperature range.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments for implementing the present invention will be described. However, this embodiment is not limited to the following content and can be arbitrarily modified and implemented within the scope that does not impair the gist of the present invention.

[0011] (Embodiment 1) FIG. 1 is a front view showing a refrigerator according to Embodiment 1. In the following description, a 6-door refrigerator 1 will be described as an example, but it is not limited to 6 doors.

[0012] As shown in FIG. 1, the heat-insulating box body 10 of the refrigerator 1 has storage rooms in the order of the refrigerating chamber 2 from above, the ice-making chamber 3 and the freezing chamber 4 provided side by side on the left and right, the first switching chamber 5, and the second switching chamber 6. The refrigerator 1 is provided with doors for opening and closing the openings of the respective storage rooms. These doors are the rotatable refrigerator doors 2a and 2b divided into left and right for opening and closing the opening of the refrigerating chamber 2, and the drawer-type ice-making chamber door 3a, freezing chamber door 4a, first switching chamber door 5a, and second switching chamber door 6a for opening and closing the openings of the ice-making chamber 3, freezing chamber 4, first switching chamber 5, and second switching chamber 6, respectively.

[0013] A display unit 19 showing typical in-cabinet settings and states is provided on the refrigerator door 2a. Door hinges (not shown) are provided at the upper and lower parts of the refrigerating chamber 2 to fix the refrigerator doors 2a and 2b to the refrigerator 1.

[0014] The refrigerating chamber 2 is a refrigerated storage chamber in which the inside of the cabinet is set to a refrigerating temperature range (0°C or higher), for example, an average of about 4°C. The ice-making chamber 3 and the freezing chamber 4 are refrigerated storage chambers in which the inside of the cabinet is set to a freezing temperature range (less than 0°C), for example, an average of about -20°C.

[0015] The first switching chamber 5 and the second switching chamber 6 are switching storage chambers in which the temperature inside the cabinet can be set to the freezing temperature range or the refrigerating temperature range. For example, they can be switched between a refrigerating mode with an average temperature of about 4°C and a freezing mode with an average temperature of about -20°C. In the refrigerator 1 of this embodiment, there are also provided a plurality of operating modes such as a super-chilling mode with a temperature between the refrigerating mode and the freezing mode, a weak-freezing mode, a super-freezing mode with a temperature lower than the freezing mode, and a vegetable mode suitable for storing vegetables in the refrigerating temperature range. These operating modes can be selected by the user through the operation unit 18 (see FIG. 2). When the refrigerator 1 is connected to a smartphone or the like via a wireless communication line or the like, the user may be able to set the temperature range of the switching storage chamber via the smartphone or the like.

[0016] FIG. 2 is a sectional view taken along line II-II of FIG. 1 in the refrigerator according to Embodiment 1. As shown in FIG. 2, the refrigerator 1 is configured such that the inside of the cabinet and the outside of the cabinet are separated by a heat-insulating cabinet 10 formed by filling a foamed heat-insulating material (for example, foamed urethane) between an outer cabinet 10a (made of steel plate) and an inner cabinet 10b (made of synthetic resin). In addition to the foamed heat-insulating material, a vacuum heat-insulating material 25 having a lower thermal conductivity than the foamed heat-insulating material is mounted between the outer cabinet 10a and the inner cabinet 10b in the heat-insulating cabinet 10, thereby improving the heat-insulating performance without reducing the food storage volume. Here, the vacuum heat-insulating material is configured by wrapping a core material such as glass wool or urethane with an outer wrapping material. The outer wrapping material includes a metal layer (for example, aluminum) to ensure gas barrier properties. Also, since the first switching chamber 5 and the second switching chamber 6 can be relatively large freezing storage chambers depending on the setting, vacuum heat-insulating materials 25 are also inserted in the door 5a of the first switching chamber 5, the door 6a of the second switching chamber 6, and the lower part of the heat-insulating cabinet 10 to improve the heat-insulating performance.

[0017] The refrigerator compartment 2, the ice-making compartment 3, and the freezer compartment 4 are separated by a heat-insulating partition wall 28. The ice-making compartment 3 and the freezer compartment 4, and the first switching compartment 5 are separated by a heat-insulating partition wall 30. The first switching compartment 5 and the second switching compartment 6 are separated by a heat-insulating partition wall 29. Inside the heat-insulating partition walls 29 and 30, a vacuum heat-insulating material 25 is inserted to ensure high heat-insulating performance with a relatively thin heat-insulating wall. Further, on the front side between the ice-making compartment 3 and the freezer compartment 4, a heat-insulating partition wall 31 is provided so that the air inside the refrigerator 1 does not leak to the outside through the gaps between the doors 3a and 4a, and the outside air does not enter each storage compartment. In this embodiment, to prevent the first switching compartment 5 and the second switching compartment 6 from becoming excessively low in temperature, an electric heater 46a for heating the first switching compartment 5 is provided at the upper part of the partition member 29, and an electric heater 46b for heating the second switching compartment 6 is provided at the lower part of the partition member 29.

[0018] Also, in the ice-making compartment 3, the freezer compartment 4, the first switching compartment 5, and the second switching compartment 6, an ice-making compartment container 3b (see FIG. 4), a freezer compartment container 4b, a first switching compartment container 5b, and a second switching compartment container 6b that are pulled out integrally with the doors 3a, 4a, 5a, and 6a are provided, respectively.

[0019] The refrigerator 1 is provided with a first evaporator 14a which is an evaporator for a refrigerated storage compartment that cools an ice-making compartment 3, a freezer compartment 4, a first switching compartment 5, and a second switching compartment 6. This first evaporator 14a is housed in a first evaporator chamber 8a provided substantially at the back of the first switching compartment 5 and the second switching compartment 6. In the first evaporator chamber 8a, the upstream side of the air flow of the first evaporator 14a may be referred to as the upstream part 8a1 of the first evaporator chamber, and the downstream side of the air flow of the first evaporator 14a may be referred to as the downstream part 8a2 of the first evaporator chamber. Above the first evaporator 14a, a first fan 9a is provided which blows the air cooled by the first evaporator 14a to the ice-making compartment 3, the freezer compartment 4, the first switching compartment 5, and the second switching compartment 6. The first switching compartment 5 and the second switching compartment 6 and the first evaporator chamber 8a are partitioned by a partition member 20a that constitutes the wall surface on the storage compartment (first switching compartment 5 and second switching compartment 6) side and a partition member 20b that constitutes the first evaporator chamber 8a side. Since the partition member 20a and the partition member 20b partition the first evaporator chamber 8a and each storage compartment and, in combination with the inner box 10b and the first evaporator tray 23a, constitute the air duct space of the first evaporator 14a, the partition member 20a and the partition member 20b are collectively referred to as the air duct component 20. Specific air ducts constituted by the air duct component 20 include an upstream common air supply duct 12 which is a space through which the air immediately after passing through the first fan 9a flows and which is partitioned by each damper (described later) for each storage compartment, and a return air duct 12d through which the air flows from the return ports of each storage compartment (ice-making compartment 3, freezer compartment 4, first switching compartment 5, and second switching compartment 6) to the upstream part 8a1 of the first evaporator chamber.

[0020] The partition member 20a is made of polypropylene which is a kind of resin member and has a thickness of 1.5 mm. The partition member 20b (foamed heat insulating material) is made of, for example, foamed polystyrene foam (expanded polystyrene). Also, the thickness of the partition member 20b is set to 30 mm in order to suppress the heat influence of the first evaporator chamber 8a on the first switching compartment 5 and the second switching compartment 6 while considering the moldability during foaming, the assemblability during refrigerator installation, and the impact resistance. Since the front of the first fan 9a is a storage compartment (switching storage compartment) where the refrigerated temperature zone is also present, heat insulation from the first evaporator chamber 8a etc. is necessary and the air duct is complicated, so a turbo fan which is a centrifugal fan with strong static pressure is used as the first fan 9a.

[0021] A defrost heater 21 for heating the first evaporator 14a is provided at the lower part of the first evaporator chamber 8a. This defrost heater 21 is, for example, an electric heater with a power of 50W to 200W and is the heater with the highest calorific value in the refrigerator 1. In this embodiment, it is a 120W radiant heater. The defrost water (melted water) generated during the defrosting of the first evaporator 14a drops into the first evaporator tray 23a provided at the lower part of the first evaporator chamber 8a, and is discharged to the evaporation tray 32 provided at the upper part of the compressor 24 through the first evaporator drain port 22a (see FIG. 6) and the first evaporator drain pipe 27a.

[0022] The second evaporator 14b, which is an evaporator for the refrigerated storage chamber, is provided in the second evaporator chamber 8b, which is a refrigerating evaporator chamber provided at the substantially back part of the refrigerating chamber 2. The air that has become low temperature by heat exchange with the second evaporator 14b is blown into the refrigerating chamber 2 by the second fan 9b provided above the second evaporator 14b through the refrigerating chamber air duct 11 and the refrigerating chamber discharge port 11a, and cools the inside of the refrigerating chamber 2. The air blown into the refrigerating chamber 2 returns to the second evaporator chamber 8b from the refrigerating chamber return port 15 through the refrigerating chamber return air duct 17 and is cooled again by the second evaporator 14b.

[0023] The second evaporator 14b performs defrosting by off-cycle defrosting in which the air in the refrigerating chamber 2 is circulated and defrosted by the heat of the refrigerating chamber 2. The defrost water generated during the defrosting of the second evaporator 14b drops into the second evaporator tray 23b provided at the lower part of the second evaporator chamber 8b, and is discharged to the evaporation tray 32 provided in the machine room 39 through the second evaporator drain port (not shown) and the second evaporator drain pipe (not shown).

[0024] On the inner back side of the refrigerator compartment 2, freezer compartment 4, first switching compartment 5, and second switching compartment 6, there are provided a refrigerator compartment temperature sensor 41, a freezer compartment temperature sensor 42, a first switching compartment temperature sensor 43, and a second switching compartment temperature sensor 44, respectively, as shown in FIG. 3A. Also, a first evaporator temperature sensor 40a is provided above the first evaporator 14a, and a second evaporator temperature sensor 40b is provided above the second evaporator 14b. The temperatures of the refrigerator compartment 2, freezer compartment 4, first switching compartment 5, second switching compartment 6, second evaporator 14b, and first evaporator 14a are detected by these sensors. Further, inside the door hinge cover 16 on the ceiling part of the refrigerator 1, there are provided an outside air temperature sensor 37 for detecting the temperature of the outside air (air outside the compartment) and an outside air humidity sensor 38 for detecting the humidity. As other sensors, there are also provided door sensors 45 (see FIG. 3A) for detecting the open / closed states of the doors 2a, 2b, 3a, 4a, 5a, 6a, and an ice-making compartment temperature sensor (not shown) for detecting the temperature of the water (ice) in the ice-making tray 3c described later, etc.

[0025] On the upper part of the refrigerator 1, there is arranged a control board (control device, control unit) 33 equipped with a CPU, a memory such as a ROM and a RAM which are part of the control device, an interface circuit, etc. The control board 33 is connected by electrical wiring (not shown) to the outside air temperature sensor 37, outside air humidity sensor 38, refrigerator compartment temperature sensor 41, freezer compartment temperature sensor 42, first switching compartment temperature sensor 43, second switching compartment temperature sensor 44, first evaporator temperature sensor 40a, second evaporator temperature sensor 40b, door sensor 45, etc.

[0026] Also, in the control board 33, based on the output values of each sensor, the settings of the operation unit 18, the programs pre-recorded in the ROM, etc., the control of the compressor 24, first fan 9a, second fan 9b, and dampers 100, 101a, 101b, 102a, 102b, which will be described later, is carried out. In addition, the refrigerator 1 of the present embodiment is provided with a communication board (not shown) that can be connected to an external device. By providing this communication board, it is possible to provide the information of the refrigerator 1 to a mobile device such as a smartphone or a personal computer, and it is also possible to change the settings such as the mode in the same way as the operation unit 18 (see FIG. 2) by operating these devices.

[0027] FIG. 3A is a front view showing the air duct configuration of the refrigerator according to Embodiment 1, and FIG. 3B is a view showing the inside of the air duct of FIG. 3A. Note that the doors 3a, 4a, 5a, 6a, and the containers 3b, 4b, 5b, 6b are omitted. FIG. 4 is a schematic view showing the air duct configuration of the refrigerator according to Embodiment 1.

[0028] The blowing of cold air to each of the storage chambers 3, 4, 5, 6 is controlled by dampers 100, 101a, 101b, 102a, 102b which are air blowing control means. Note that the dampers 101a, 101b are controlled by one motor provided in the drive unit 101c, and the dampers 102a, 102b are also controlled by one motor provided in the drive unit 102c, so as to reduce the number of motors with respect to the number of dampers, aiming for cost reduction and space saving. Also, the air duct through which the air passing through each damper flows to each storage chamber may be referred to as a downstream individual air blowing duct.

[0029] When cooling the ice making chamber 3 and the freezer chamber 4, the damper 100 for controlling the air blowing to the ice making chamber 3 and the freezer chamber 4 is opened, and the first fan 9a provided above the first evaporator 14a exchanges heat with the first evaporator 14a to make the air (cold air) at a low temperature pass through the downstream part 8a2 of the first evaporator chamber, the upstream common air blowing duct 12, the freezer damper 100, the downstream individual air blowing duct (ice making / freezer chamber air duct 110), the ice making chamber outlet 120a or the freezer chamber outlet 120b, and is blown into the ice making chamber 3 or the freezer chamber 4 to cool the water in the ice tray 3c in the ice making chamber 3, the ice in the container 3b, the food in the container 4b in the freezer chamber 4, etc. Note that the water in the ice tray 3c is supplied from the ice making tank 36 shown in FIG. 3B by an ice making pump (not shown). The air that has cooled the ice making chamber 3 or the freezer chamber 4 returns from the ice making / freezer chamber return port 130 through the return air duct 12d to the upstream part 8a1 of the first evaporator chamber and is cooled again by the first evaporator 14a.

[0030] The first switching chamber 5 changes the cold air blowing between the freezing mode and the refrigerating mode. Note that the above-described vegetable mode will be described as a part of the refrigerating mode. When the first switching chamber 5 is in the freezing mode, the damper 101a, which is the direct cooling damper of the first switching chamber 5, is opened, and the damper 101b, which is the indirect cooling damper, is closed. The air cooled by the first evaporator 14a passes through the downstream part 8a2 of the first evaporator chamber, the first fan 9a, the upstream common air duct 12, the damper 101a, the downstream individual air duct (the first switching chamber direct cooling air duct 111a), and the first switching chamber direct cooling air outlet 121a, which is the direct cooling air outlet of the first switching chamber 5, and is blown into the first switching chamber container 5b provided in the first switching chamber 5 to cool the food in the first switching chamber container 5b. Since the cold air directly cools the food in the first switching chamber container 5b, the food in the first switching chamber container 5b can be cooled in a relatively short time. When the first switching chamber 5 is in the refrigerating mode, the damper 101a is closed, and the damper 101b, which is the indirect cooling damper of the first switching chamber 5, is opened. The air cooled by the first evaporator 14a passes through the downstream part 8a2 of the first evaporator chamber, the first fan 9a, the upstream common air duct 12, the damper 101b, the downstream individual air duct (the first switching chamber indirect cooling air duct 111b), and the first switching chamber indirect cooling air outlet 121b, which is the indirect cooling air outlet of the first switching chamber 5, and is blown toward the outside (outer periphery) of the first switching chamber container 5b. It becomes difficult for the cold air to directly reach the food in the first switching chamber container 5b, that is, since the food is indirectly cooled through the first switching chamber container 5b, the food can be cooled while suppressing drying. The air that is discharged from the first switching chamber direct cooling air outlet 121a or the first switching chamber indirect cooling air outlet 121b and cools the inside of the first switching chamber returns to the upstream part 8a1 of the first evaporator chamber through the return air duct 12d from the first switching chamber return port 131 and is cooled again by the first evaporator 14a.

[0031] Note that since the temperature difference between the storage chamber and the outside air is larger and the load required for cooling is larger in the freezing mode, the damper 101a mainly used in the freezing mode has a larger opening area to increase the air volume compared to the damper 101b mainly used in the refrigerating mode. On the other hand, the damper 101b has a smaller opening area (size) to make the internal volume of the storage chamber as large as possible.

[0032] Similar to the first switching chamber 5, the second switching chamber 6 also changes the opening and closing of the damper according to the operation mode. When the second switching chamber 6 is in the refrigeration mode, the damper 102a, which is the direct cooling damper of the second switching chamber 6, is opened, and the damper 102b, which is the indirect cooling damper, is closed. The air (cold air) cooled by the first evaporator 14a passes through the first fan 9a, the upstream common air duct 12, the damper 102a, the downstream individual air duct (the second switching chamber direct cooling air duct 112a), and the second switching chamber direct cooling air outlet 122a, which is the direct cooling air outlet of the second switching chamber 6, and is blown into the second switching chamber container 6b to cool the food on the second switching chamber container 6b. Since the cold air directly cools the food in the second switching chamber container 6b, the food in the second switching chamber container 6b can be cooled in a relatively short time. When the second switching chamber 6 is in the refrigerated mode, the damper 102a is closed, and the damper 102b, which is the indirect cooling damper of the second switching chamber 6, is opened. The air cooled by the first evaporator 14a is blown to the outside (outer periphery) of the second switching chamber container 6b through the downstream part 8a2 of the first evaporator chamber, the first fan 9a, the upstream common air duct 12, the damper 102b, the downstream individual air duct (the second switching chamber indirect cooling air duct 112b), and the second switching chamber indirect cooling air outlet 122b, which is the indirect cooling air outlet of the second switching chamber 6, and cools the food while suppressing the drying of the food as indirect cooling. The air that has cooled the inside of the second switching chamber 6 returns from the second switching chamber return port 132 to the upstream part 8a1 of the first evaporator chamber and is cooled again by the first evaporator 14a.

[0033] Similar to the dampers 101a and 101b, the damper 102a, which is mainly used in the freezing mode, has a larger opening area than the damper 102b, which is mainly used in the refrigerated mode.

[0034] Also, in the refrigerated mode, especially in the refrigerated mode other than the vegetable mode, when the temperature inside the cabinet is higher than a predetermined value (for example, when it is 10°C or more higher than the reference temperature), the dampers 101a and 102a, which are the direct cooling dampers, may be opened so that the inside of the cabinet can be cooled to the predetermined temperature in a short time. Also, in the freezing mode, when the temperature inside the cabinet is higher than a predetermined value (for example, when it is 10°C or more higher than the reference temperature), in addition to the dampers 101a and 102a, the dampers 101b and 102b may also be opened simultaneously to increase the air volume and enhance the cooling capacity.

[0035] FIG. 5 is a configuration diagram showing the refrigeration cycle of the refrigerator according to Embodiment 1. As shown in FIG. 5, the refrigerator 1 includes a compressor 24, an outdoor radiator 50a and a wall surface heat radiation pipe 50b which are heat radiation means for radiating the refrigerant, partition walls 28, 29, 30 (see FIGS. 1 and 2), a dew condensation prevention pipe 50c for suppressing dew condensation on the front surfaces thereof, a first capillary tube 53a and a second capillary tube 53b which are pressure reducing means for reducing the pressure of the refrigerant, and a first evaporator 14a and a second evaporator 14b for exchanging heat between the refrigerant and the air in the refrigerator to absorb the heat in the refrigerator.

[0036] Further, the refrigerator 1 includes a drier 51 for removing moisture during the refrigeration cycle, gas-liquid separators 54a and 54b for preventing the liquid refrigerant from flowing into the compressor 24, a three-way valve 52 for controlling the refrigerant flow path, a check valve 56, and a refrigerant confluence portion 55 for connecting the refrigerant flows. By connecting these with refrigerant pipes, a refrigeration cycle is configured.

[0037] Note that the refrigerator 1 uses 80 g of flammable refrigerant isobutane as the refrigerant. Further, the compressor 24 includes an inverter and can change the rotation speed. The three-way valve 52 includes two outlets 52a and 52b, and is a member that can switch between a refrigeration operation in which the refrigerant flows to the outlet 52a side and a refrigeration operation in which the refrigerant flows to the outlet 52b side. Further, the three-way valve 52 can also switch between a fully closed mode in which no refrigerant flows through either of the outlets 52a and 52b and a fully open mode in which refrigerant flows through both.

[0038] Also, the refrigerant in the refrigerator 1 flows as follows. That is, the refrigerant discharged from the compressor 24 flows in the order of the outdoor radiator 50a, the wall surface heat radiation pipe 50b, the dew condensation prevention pipe 50c, and the drier 51, and reaches the three-way valve 52. The outlet 52a of the three-way valve 52 is connected to the first capillary tube 53a via a refrigerant pipe. The outlet 52b of the three-way valve 52 is connected to the second capillary tube 53b via a refrigerant pipe.

[0039] When the refrigerant flows through the three-way valve 52 toward the outlet 52a, the refrigerant flowing out from the outlet 52a flows in the order of the first capillary tube 53a, the first evaporator 14a, the gas-liquid separator 54a, the check valve 56, and the refrigerant confluence part 55, and then returns to the compressor 24. The check valve 56 is arranged such that the refrigerant flows from the gas-liquid separator 54a toward the refrigerant confluence part 55 side and does not flow from the refrigerant confluence part 55 toward the gas-liquid separator 54b side. The refrigerant that has become low-pressure and low-temperature in the first capillary tube 53a flows through the first evaporator 14a, causing the first evaporator 14a to become low-temperature, and the air in the first evaporator chamber 8a (see FIG. 2) can be cooled. By blowing this air into the ice-making chamber 3, the refrigerating chamber 4, the first switching chamber 5, and the second switching chamber 6, the ice-making chamber 3, the refrigerating chamber 4, the first switching chamber 5, and the second switching chamber 6 are cooled.

[0040] On the other hand, when the refrigerant flows through the three-way valve 52 toward the outlet 52b, the refrigerant flowing out from the outlet 52b flows in the order of the second capillary tube 53b, the second evaporator 14b, the gas-liquid separator 54b, and the refrigerant confluence part 55, and then returns to the compressor 24. The refrigerant that has become low-pressure and low-temperature in the second capillary tube 53b flows through the second evaporator 14b, causing the second evaporator 14b to become low-temperature, and the air in the second evaporator chamber 8b (see FIG. 2) can be cooled. By blowing this air into the refrigerating chamber 2, the refrigerating chamber 2 is cooled.

[0041] FIG. 6 is a view showing the back surface of the air duct component 20 according to Embodiment 1, and is a view showing the vicinity of the air duct component 20 in the III-III cross section of FIG. 2. A communication hole 200 communicating with the upstream part 8a1 of the first evaporator chamber is provided in the lower part of the upstream common air duct 12. As described above, the air duct component 20 is a component that forms the air duct space (the first evaporator chamber 8a, the upstream common air duct 12, and the return air duct 12d) of the first evaporator 14a in combination with the inner box 10b and the first evaporator case 23a.

[0042] In the refrigerator 1 of Embodiment 1, in order to defrost the frost adhering to the first evaporator 14a, the compressor 24 is stopped, and a defrost operation is performed in which the defrost heater 21 is energized to heat the first evaporator 14a. Inside the air duct component 20, condensation or frosting may occur due to, for example, air that has passed through the first evaporator 14a and become highly humid during this defrost operation. If the water generated thereby remains in the air duct component 20, there is a risk that the air duct may be blocked by water or ice, or that normal cooling may become impossible due to icing of the first fan 9a, dampers 100, 101a, 101b, 102a, 102b, etc. Therefore, it is necessary to appropriately discharge the water. Accordingly, a communication hole 200 communicating with the upstream part 8a1 of the first evaporator chamber is provided at the lower part of the air duct component 20 so as to collect the water generated on the inner wall of the upstream common air duct 12 and discharge this water from the air duct component 20. The water discharged from the communication hole 200 falls into the first evaporator tray 23a provided at the lower part of the upstream part 8a1 of the first evaporator chamber, and together with the defrost water of the first evaporator 14a, is discharged to the evaporation tray 32 (see FIG. 2) via the first evaporator drain port 22a and the first evaporator drain pipe 27a. In the present embodiment, in order to suppress the air directed toward the first fan 9a without passing through the first evaporator 14a, communication suppression members 14c are provided on the left and right sides of the first evaporator 14a, and the lower side (upstream side) of the communication suppression member 14c is the upstream part 8a1 of the first evaporator chamber, and the upper side (downstream side) is the downstream part 8a2 of the first evaporator chamber.

[0043] In the present embodiment, in order to also cause the communication hole 200 to function as a drain port, the communication hole 200 is arranged at the lowermost part of the upstream common air duct 12 with the length of each side of the opening being 5 mm or more so that water can flow. Also, in order to suppress the amount of air flowing through the communication hole 200 during the cooling operation, it is made smaller than the other dampers 100, 101a, 101b, 102a, 102b, specifically, with the length of each side of the opening being 20 mm or less. By making the opening area of the communication hole 200 relatively small, the relative amount of air flowing through the communication hole 200 during the cooling operation is suppressed, and while suppressing an increase in cost due to the addition of a damper, a decrease in the amount of air blown into the storage chamber during the cooling operation and a decrease in the cooling capacity are suppressed.

[0044] Here, in the refrigerator 1 of the present embodiment, when the first fan 9a is driven, air flows in the order of the defrost heater 21, the first evaporator 14a, and the first fan 9a. Further, a communication hole 200 is provided so as to communicate the upstream common air passage 12 downstream of the air flow of the first fan 9a and the upstream portion 8a1 of the first evaporator chamber upstream of the air flow of the defrost heater 21. That is, when the first fan 9a is driven, the communication hole 200 functions as a communication portion through which air can circulate among the defrost heater 21, the first evaporator 14a, and the first fan 9a without passing through the storage chamber. This communication portion is particularly useful during the defrost operation of the first evaporator 14a, and the control of this defrost operation and its effects will be described below. Note that the following defrost operation represents the defrost operation of the first evaporator 14a.

[0045] FIG. 7 is an example of a temperature chart of the defrost operation when both the first switching chamber 5 and the second switching chamber 6 are in the refrigeration mode, and FIG. 8 is an example of a control flowchart of the defrost operation when both the first switching chamber 5 and the second switching chamber 6 are in the refrigeration mode. In FIGS. 7 and 8, the control of the defrost operation for the second evaporator 14b is omitted, and only the freezer compartment temperature T F detected by the freezer compartment temperature sensor 42 as a representative of the storage chambers in the refrigeration temperature zone is shown.

[0046] There are a plurality of start conditions for the defrost operation in the refrigerator 1 of the present embodiment. For example, during the cooling operation (control S0), when the integrated rotation speed of the compressor 24 reaches a predetermined value (time T d0、 control S1), a pre-cooling operation for cooling the ice-making chamber 3, the freezer compartment 4, the first switching chamber 5, and the second switching chamber 6, which are storage chambers in the refrigeration temperature zone, is started (control S2). The pre-cooling operation ends, for example, after 30 minutes or when all the storage chambers reach a predetermined value (control S3), the compressor 24 is stopped, and the defrost operation of the first evaporator 14a in which the defrost heater 21 is energized is started (time t d1 , control S4). In the defrost operation of the present embodiment, first, a fan-stop defrost (second defrost operation) is performed in a state where the dampers 100, 101a, and 102a are closed and the dampers 101b and 102b are open, and the first fan 9a is stopped for defrosting (control S5). In this state, when the defrost time reaches a predetermined time Δt d1The first evaporator temperature T that elapses or is detected by the first evaporator temperature sensor 40a E becomes, for example, a predetermined value T of -15°C d1 or higher (control S6), all dampers 100, 101a, 101b, 102a, 102b are closed, and the operation shifts to defrosting using the duct internal circulation fan that drives the first fan 9a (the first defrosting operation) (time t d2 , control S7).

[0047] FIG. 9 shows the air flow during defrosting using the duct internal circulation fan, that is, the air flow when all dampers are closed and the first fan 9a is driven, appended to FIG. 6. At this time, the air heated by the defrosting heater 21 flows through the upstream part 8a1 of the first evaporator chamber, the first evaporator 14a, the downstream part 8a2 of the first evaporator chamber, the first fan 9a, the upstream common air duct 12, and the communication hole 200, returns to the upstream part 8a1 of the first evaporator chamber, and is heated again by the defrosting heater 21.

[0048] After shifting to defrosting using the duct internal circulation fan, when the first evaporator temperature becomes higher than 0°C, for example, a predetermined temperature T of 8°C d_off or higher (time t d3 , control S8), the power supply to the defrosting heater 21 is stopped (control S9; afterheat operation). If this state is continued for a predetermined time ΔT of, for example, 3 minutes (time t d2 , control S10), the three-way valve 52 is switched to the outlet 52a side (the first evaporator 14a side), and the compressor 24 is driven (control S11; precooling operation). In this state, when the first evaporator temperature reaches a predetermined temperature T lower than 0°C d4 , for example, -10°C or lower (control S12, time t d2 d5 ), the defrosting operation control ends (control S13). In this embodiment, also in the afterheat operation and the precooling operation, as in the defrosting using the duct internal circulation fan, all dampers 100, 101a, 101b, 102a, 102b are closed and the first fan 9a is driven. When the precooling operation (controls S11, S12) ends, the cooling operation (control S1) that appropriately opens and closes each damper 100, 101a, 101b, 102a, 102b again to control each storage chamber to a predetermined temperature is resumed.

[0049] ​ Explain the effects obtained by this defrost operation control.

[0050] During the defrost operation, the first evaporator 14a is heated by the convection of the air heated by the defrost heater 21 together with the radiation from the defrost heater 21. Here, if the first fan 9a is stopped, the convection becomes natural convection, so the heat transfer becomes weak. On the contrary, when the first fan 9a is driven, it becomes forced convection and the heat transfer is improved, and the heating efficiency of the first evaporator 14a can be improved. That is, the frost attached to the first evaporator 14a can be melted in a short time with less energy, and the energy-saving performance can be improved.

[0051] Also, when the defrost heater 21 is driven under the natural convection condition where the first fan 9a is not driven, the air heated by the defrost heater 21 may convect in a direction different from that of the first evaporator 14a (for example, the return air duct 12d, the first switching chamber return port 131, the second switching chamber return port 132), and the heating efficiency may decrease. On the other hand, in the defrosting using the duct internal circulation fan, as shown in FIG. 9, due to the forced convection by the first fan 9a, the air more surely flows from the defrost heater 21 toward the first evaporator 14a, so the effect of suppressing the decrease in this heating efficiency can also be obtained.

[0052] Here, if the air passing through the first fan 9a does not properly return to the defrost heater 21, the air cannot circulate and the aforementioned flow field cannot be formed. In particular, when both the first switching chamber 5 and the second switching chamber 6 are in the refrigeration mode, all the storage chambers (the ice-making chamber 3, the freezer compartment 4, the first switching chamber 5, the second switching chamber 6) cooled by the first evaporator 14a become storage chambers set to the refrigeration temperature range. Therefore, when the air in the first evaporator chamber 8a whose temperature has risen during the defrost operation is blown into the storage chambers, the food temperature rises, and problems such as ice and frozen food melting occur. On the other hand, by providing the communication hole 200 so as to communicate the upstream common air passage 12 and the upstream portion 8a1 of the first evaporator chamber, the dampers 100, 101a, 100b, 102a, 102b can form the air flow shown in FIG. 9 while suppressing the air supply to all the storage chambers cooled in the first evaporator chamber 8a, and the effect of defrosting using the duct internal circulation fan can be obtained. That is, even if all the storage chambers cooled by the first evaporator 14a are in the refrigeration temperature range, a refrigerator can be provided that can obtain the effect of improving the efficiency of the defrost operation using forced convection by the fan.

[0053] Also, in the refrigerator 1 of the present embodiment, the defrosting using the duct internal circulation fan is carried out until the temperature of the first evaporator becomes higher than 0°C (8°C or higher) (control S8). As a result, air exceeding 0°C also flows through the downstream side of the first evaporator 14a, that is, the first fan 9a, the wall surface of the upstream common air passage 12, each damper 100, 101a, 101b, 102a, and 102b arranged to separate the upstream common air passage 12 from the downstream individual air passages, and the communication hole 200, and frost and ice can be melted at these locations.

[0054] Note that this effect is particularly important for the dampers 102a and 102b. In the refrigerator 1 of the present embodiment, as shown in FIG. 6 and the like, since the dampers 102a and 102b are provided below the first fan 9a and above the communication hole 200, by performing defrosting using the duct internal circulation fan, the heating efficiency of the dampers 102a and 102b can also be increased. Basically, in natural convection, warm air flows upward. Therefore, the air heated by the defrost heater 21 that reaches the first fan 9a hardly flows to the dampers 102a and 102b arranged below the first fan 9a. In a refrigerator that performs defrosting only by natural convection, a heater for melting the frost on the dampers 102a and 102b is likely to be required. On the other hand, by performing defrosting using the duct internal circulation fan and forming the flow field shown in FIG. 9, the air heated by the defrost heater 21 flows along the upstream common air supply path 12 side of the dampers 102a and 102b and reaches the communication hole 200. As a result, the heating efficiency of the dampers 102a and 102b can be increased, the power consumption of the heater required to melt the frost on the dampers 102a and 102b can be reduced, or the heater arrangement can be made unnecessary to reduce the cost. Here, the temperature of the dampers 102a and 102b can be efficiently increased immediately after the start of the defrost operation. However, in order to melt the frost and ice adhering to the dampers 102a and 102b, it is necessary to heat the dampers 102a and 102b to 0°C or higher. Therefore, it is particularly effective when the first evaporator temperature is 0°C or higher, which is the melting temperature of frost and ice. That is, in order to melt the frost and ice on the downstream side of the first evaporator 14a, it is necessary to heat the air that has passed through the first evaporator temperature to above 0°C during the time (time t in FIG. 7 d6 ~t d5 ). The effect of improving the heating efficiency by this control during this time period becomes important.

[0055] Also, the refrigerator 1 of the present embodiment has a predetermined time (Δt after the energization of the defrost heater 21 ends d2 ; time t d3 ~t d4) Without driving the compressor 24, by driving the first fan 9a to perform the waste heat operation of the flow field shown in FIG. 9, while suppressing the heating by the defrost heater 21, air at a temperature higher than 0°C is passed downstream of the first evaporator 14a, and the frost and ice downstream of the first evaporator 14a can be more reliably melted. In addition, in order to ensure the time until the defrost water melted during the defrost operation reaches the drain port 22a for the first evaporator, the waste heat operation for maintaining the first evaporator 14a and the first evaporator chamber 8a in a state exceeding 0°C is effective. Note that the duct internal circulation fan utilization defrost may be performed until a predetermined time has elapsed (for example, 3 minutes have elapsed at 8°C or higher) after the temperature of the first evaporator reaches a temperature higher than 0°C. However, since this control that shifts to the waste heat operation after reaching a temperature higher than 0°C can suppress the energization time of the defrost heater 21, that is, the power consumption, the energy saving performance can be improved.

[0056] Furthermore, in the refrigerator 1 of the present embodiment, after the waste heat operation, while driving the first fan 9a, the three-way valve 52 is set to the outlet 52a side (the first evaporator 14a side) to drive the compressor 24, and until the first evaporator temperature becomes -10°C or lower, which is lower than 0°C, each damper 100, 101a, 101b, 102a, and 102b is closed, and a precooling operation is performed to suppress the blowing to each storage chamber. Thereby, the heating of the storage chamber in the freezing temperature zone by the warm air in the first evaporator chamber 8a whose temperature has risen during the defrost operation is suppressed. Note that during the precooling operation, instead of closing each damper 100, 101a, 101b, 102a, and 102b, a similar effect can be obtained by stopping the first fan 9a and starting the blowing after the first evaporator 14a becomes low temperature. However, as in the present embodiment, by driving the first fan 9a during the precooling operation to form the flow shown in FIG. 9, in addition to the first evaporator 14a, the air passage and the structure from the first evaporator 14a to each damper, that is, the first evaporator chamber 8a, the first fan 9a, the upstream common blowing passage 12, and each damper can be made low temperature and the blowing to each storage chamber can be started, and the intrusion of warm air into the storage chamber in the freezing temperature zone can be more reliably suppressed.

[0057] In the refrigerator 1 of the present embodiment, in addition to the defrosting using the duct internal circulation fan (first defrosting operation), the first fan 9a is stopped with the dampers 100, 101a, and 102a closed and the dampers 101b and 102b open (fan stop defrosting: second defrosting operation). In the fan stop defrosting, since the influence of convection is weaker than when the first fan 9a is driven, the temperature of the defrost heater 21 is higher and the influence of radiation is stronger. Therefore, it is possible to promote the heating of the first evaporator toy 23a, the first evaporator drain port 22a, etc., which are located upstream of the air flow from the defrost heater 21 that is difficult to heat by forced convection. Since the defrost water is drained from the first evaporator drain port 22a, it is necessary to take measures so that these locations do not freeze during the defrosting operation. Therefore, the defrosting efficiency of the first evaporator 14a where frost grows most is improved by the defrosting using the duct internal circulation fan on the downstream side of the air flow of the defrost heater 21, and the frost and ice on the upstream side of the air flow from the defrost heater 21 can be more easily melted, that is, the freezing of the first evaporator toy 23a, the first evaporator drain port 22a, etc. can be more reliably suppressed. Note that the reason for opening the dampers 101b and 102b during the fan stop defrosting is to form a circulation flow field of natural convection while suppressing the intrusion of warm air into the storage chamber by opening dampers with a relatively small opening area so that the temperature of the defrost heater 21 does not rise too much because the refrigerant uses flammable isobutane.

[0058] Here, since the fan-off defrost is greatly affected by radiation, in the refrigerator 1 of this embodiment, the fan-off defrost is performed before the duct internal circulation fan utilization defrost. When the frost accumulation amount on the first evaporator 14a is large and the ventilation resistance of the first evaporator 14a is large, and the duct internal circulation fan utilization defrost is performed, even if the first fan 9a is driven, for example, air heated by the defrost heater 21 flows from outside the first evaporator 14a such as the gap around the communication suppression member 14c, and it becomes difficult for the heat of the defrost heater 21 to reach the first evaporator 14a. On the other hand, when the frost accumulation amount on the first evaporator 14a is large, since the area of the frost adhering to the first evaporator 14a that is affected by the radiation of the defrost heater 21 is large, it is relatively easy to be heated even during the fan-off defrost where the radiation effect is large. Therefore, in this embodiment, by performing the fan-off defrost before the duct internal circulation fan utilization defrost, the fan-off defrost is performed in the initial state (when the frost accumulation amount is large) where the ventilation resistance of the first evaporator 14a is large and it is easily affected by the radiation of the defrost heater 21, and the duct internal circulation fan utilization defrost is performed after the ventilation resistance becomes small, thereby enhancing the defrost efficiency improvement effect by the above-mentioned forced convection.

[0059] In addition, for example, if it can be determined that the frost accumulation amount on the first evaporator 14a is small or the ventilation resistance of the first evaporator 14a is small based on the cumulative time of door opening and closing or the ambient humidity from the previous defrost operation to the start of the next defrost operation, the fan-off defrost may not be performed or the time may be shortened. In this embodiment, when the humidity detected by the outside air humidity sensor 38 is, for example, 80%RH or less and the cumulative time of door opening and closing is short, for example, about 5 minutes, it is determined that the frost accumulation amount on the first evaporator 14a is small, and the fan-off defrost is omitted and the process proceeds to the duct internal circulation fan utilization defrost. Since the ventilation resistance of the first evaporator 14a is small from the initial stage of the defrost operation, the defrost efficiency improvement effect by the forced convection of the duct internal circulation fan utilization defrost can be obtained from the initial stage of defrost, and the energy saving performance can be further enhanced.

[0060] However, in the refrigerator 1 of the present embodiment, when the defrost operation that suppresses the fan-stop defrosting is continuously performed, for example, twice, the next defrost operation will always be normal (the control shown in FIGS. 7 and 8), or a fan-stop defrosting for a longer time will be performed. During the defrost operation that suppresses the fan-stop defrosting with a small amount of frost accumulation on the first evaporator 14a, since the amount of water that needs to be drained from the drain port 22a for the first evaporator is small, the possibility of the defrost water overflowing from the drain 23a for the first evaporator in one defrost operation is low. On the other hand, in order to prevent the drain 23a for the first evaporator from continuously accumulating, a fan-stop defrosting that promotes the heating of the drain port 22a for the first evaporator is performed once every three times. At that time, by surely releasing the freezing of the drain port 22a for the first evaporator, the defrost water stored in the drain 23a for the first evaporator is surely drained.

[0061] Next, when the storage chamber cooled by the first evaporator 14a includes a storage chamber in the refrigerating temperature zone, as an example, the case where the first switching chamber 5 is set to the refrigerating temperature zone and the second switching chamber 6 is set to the freezing temperature zone will be described below.

[0062] FIG. 10 shows the air flow during defrosting using the storage chamber circulation fan when the first switching chamber 5 is set to the refrigerating temperature zone and the second switching chamber 6 is set to the freezing temperature zone. When the storage chamber in the refrigerating temperature zone is included, defrosting using the storage chamber circulation fan (third defrosting operation) that performs defrosting while blowing air into the storage chamber in the refrigerating temperature zone can be performed. In the defrosting using the storage chamber circulation fan, the damper 101b that controls the air blowing of the first switching chamber 5 in the refrigerating temperature zone is opened, the other dampers are closed, the defrosting heater 21 is energized, and the first fan 9a is driven. By opening the damper 101b and driving the first fan 9a, the air that has passed through the first evaporator 14a flows into the first switching chamber 5 through the downstream part 8a2 of the first evaporator chamber, the first fan 9a, the upstream common air duct 12, the damper 101b, the downstream individual air duct (the first switching chamber cold air duct 111b), and the first switching chamber cold air outlet 121b. Also, the air in the first switching chamber 5 returns to the first evaporator 14a through the return air duct 12d and the upstream part 8a1 of the first evaporator chamber via the first switching chamber return port 131. Due to this air circulation, similar to the defrosting using the duct internal circulation fan, the effect of improving the efficiency of the defrosting operation by forced convection can be obtained, and heat exchange occurs between the first switching chamber 5 and the first evaporator 14a. The frost (with a melting temperature of 0°C or lower) on the first evaporator 14a can be heated by the air in the first switching chamber 5 in the refrigerating temperature zone (0°C or higher), and the heating amount of the defrosting heater 21 can be further suppressed. In addition, since the air cooled to a low temperature by the first evaporator 14a can also cool the first switching chamber 5 in the refrigerating temperature zone, a defrosting operation with high energy-saving performance is achieved.

[0063] Defrosting using the storage chamber circulation fan can improve the efficiency of the defrosting operation using the first fan 9a without blowing warm air during defrosting into the storage chamber in the freezing temperature zone, and in addition, the first switching chamber 5 can be cooled. However, if the food stored in the storage chamber in the refrigerating temperature zone becomes too cold, the food may freeze, or in the case of, for example, vegetables, the quality of the food may deteriorate due to cold damage or the like. Therefore, it is necessary to suppress excessive cooling of the storage chamber set in the refrigerating temperature zone. Specifically, when the outside air is at a low temperature, the cooling load is small, and it is easy to get cold, or when the first evaporator 14a is at a low temperature immediately after the start of the defrosting operation, in the case of a storage chamber assuming the storage of vegetables (when set to the vegetable mode of this embodiment or a storage chamber marked as a vegetable chamber), etc., it is necessary to consider the deterioration of the quality of the food due to excessive cooling and the deterioration of the energy-saving performance due to the heating of the electric heater to suppress excessive cooling. Note that the reason for opening the damper 101b, which is an indirect cooling damper instead of the damper 101a, during defrosting using the storage chamber circulation fan is to prevent the air of the low-temperature first evaporator 14a from directly cooling the food immediately after the start of the defrosting operation. In particular, in a storage chamber assuming the storage of vegetables (when the first switching chamber 5 is in the vegetable mode), it is effective to suppress the deterioration of the freshness of the food due to low-temperature and low-humidity air.

[0064] Figure 11 is a flowchart during the defrosting operation when the first switching chamber 5 is set to the refrigerating temperature zone and the second switching chamber 6 is set to the freezing temperature zone. When the defrosting operation starts and the defrosting heater 21 is energized, as in the case of any of the freezing temperature zones described with reference to FIGS. 7 and 8, first, the dampers 100, 101a, and 102a are closed, and the dampers 101b and 102b are open, and the first fan 9a is stopped to perform fan-stop defrosting (controls S0 to S5). In this state, when a predetermined time Δt, for example, 5 minutes, has elapsed, or when the temperature T of the first evaporator detected by the first evaporator temperature sensor 40a becomes equal to or higher than a predetermined temperature T, for example, -15°C (control S6), control S30 for determining whether to perform defrosting using the duct internal circulation fan or defrosting using the storage chamber circulation fan is performed. d1 has elapsed as described above, or the temperature T of the first evaporator detected by the first evaporator temperature sensor 40a E becomes equal to or higher than a predetermined temperature T, for example, -15°C d1 (control S6), control S30 for determining whether to perform defrosting using the duct internal circulation fan or defrosting using the storage chamber circulation fan is performed.

[0065] In control S30, when the first switching chamber 5 is in the refrigeration mode, the outside air temperature T around the refrigerator detected by the outside air temperature sensor 37 out is, for example, 15°C of T out_h In the following cases, or when the temperature T of the first switching chamber detected by the first switching chamber temperature sensor 43 S1 is, for example, 2°C of T S1_h In the following cases, the control shifts to the defrosting using the duct internal circulation fan in control S31, and in other cases, it shifts to the defrosting using the storage chamber circulation fan in control 33. Here, even when the control shifts to the defrosting using the duct internal circulation fan in control S30, when the temperature T of the first evaporator E is, for example, a predetermined temperature T of -2°C d2 or higher, it is considered that the risk of freezing of food is low, and the control shifts to the defrosting using the storage chamber circulation fan in control S33 (performing control S32). However, during the defrosting using the storage chamber circulation fan, when the temperature T of the first switching chamber S1 is the predetermined temperature T S1_L , for example, 0°C or lower in the refrigeration mode, or 4°C or lower when the first switching chamber temperature is in the vegetable mode, the control shifts to the defrosting using the duct internal circulation fan to prevent freezing and low-temperature damage (control S34). As described above, the defrosting using the storage chamber circulation fan (the third defrosting operation) with the highest energy-saving performance is effectively used within the range that does not affect food freshness, and when there is concern about excessive cooling, the defrosting using the duct internal circulation fan (the first defrosting operation) with higher energy-saving performance (higher defrosting efficiency) than the fan-stop defrosting is performed, so that it is possible to perform a defrosting operation with high energy-saving performance while suppressing the deterioration of food.

[0066] Next, when the temperature of the first evaporator is higher than the melting temperature of frost or ice, a predetermined temperature of 0°C, for example, a predetermined temperature T of 3°C d3 or higher, the control shifts to the defrosting using the duct internal circulation fan in control S7 (control S34). By switching this defrosting operation, while suppressing the blowing of air higher than the first switching chamber 5 to heat the first switching chamber 5, it is possible to flow air at a temperature equal to or higher than the melting temperature of frost in the upstream common air duct 12 by forced convection, and to efficiently melt the frost and ice on the damper 100, 101a, 101b, 102a, and 102b arranged in the upstream common air duct 12 and at the boundary of the upstream common air duct 12. After that (controls S7 to S12), it is the same as the control shown in FIGS. 7 and 8.

[0067] Here, in the case of a refrigerator in which the storage chamber in the refrigerating temperature range is likely to become low in temperature, it is necessary to heat the storage chamber by an electric heater or the like to keep the inside of the storage chamber at a predetermined temperature. In the refrigerator of the present embodiment, particularly when the first switching chamber 5 is in the refrigerating temperature range and the second switching chamber 6 is in the freezing temperature range, the upper and lower parts of the first switching chamber 5 are storage chambers in the freezing temperature range (the ice-making chamber 3, the freezing chamber 4, and the second switching chamber 6), and the back surface is the first evaporator chamber 8a. Therefore, since the storage chamber in the refrigerating temperature range is cooled by heat conduction from the surroundings or the like, when the surroundings are at a low temperature or when the temperature of the first switching chamber becomes low, it is necessary to perform heating with the electric heater 46a. Therefore, when the storage chamber circulation fan is used for defrosting with the first evaporator 14a in a low-temperature state, the temperature of the first switching chamber is cooled, and thus the heating amount of the electric heater 46a increases. However, as in the present embodiment, by suppressing the defrosting using the storage chamber circulation fan according to the outside air temperature or the temperature inside the cabinet, the power consumption of the electric heater 46a required to maintain a predetermined temperature can be suppressed. In addition, by using the defrosting using the duct internal circulation fan at this time, an effect of improving the defrosting efficiency by forced convection can be obtained as compared with the case where the fan stop defrosting is performed, and the most energy-saving defrosting operation in terms of overall performance is achieved. Further, when the set temperature is high within the refrigerating temperature range (vegetable mode in the present embodiment), heating by the electric heater 46a is likely to be required. Therefore, this effect is particularly effective when the set temperature is high (vegetable mode).

[0068] In the refrigerator of the present embodiment, the communication hole 200 which is also a drain port is used as the communication part, and the air of the defrosting heater 21 is circulated during the defrosting using the duct internal circulation fan. However, as a communication part having no drainage function, the communication hole 200 may be arranged at a position other than the lowermost part of the upstream common air supply passage 12. Further, each damper (air flow control means) of the present embodiment is preferably one that can completely block the air passage. For example, the opening area during the defrosting using the duct internal circulation fan may be blocked until it becomes 1 / 10 or less of the opening area of the air passage at the part where the damper is installed, and the air flow may be suppressed to a certain extent.

[0069] (Embodiment 2) Next, Embodiment 2 of the present invention will be described. The configuration of this embodiment can be made the same as that of Embodiment 1 except for the following points. Embodiment 2 is an example of a refrigerator having a communication duct that connects the upstream common air duct 12 and the return air duct 12d as a communication part through which air can circulate between the defrost heater 21, the first evaporator 14a, and the first fan 9a without passing through the storage chamber, and is provided with a damper that controls the air supply to the communication duct.

[0070] FIG. 12 is a view showing the back surface of the air duct component 20 according to Embodiment 2, with the flow of air during defrosting using the duct internal circulation fan when both the first switching chamber and the second switching chamber according to Embodiment 2 are in the refrigeration mode indicated by arrows. In the refrigerator 1 of Embodiment 2, a communication duct 210 is provided that communicates between the upstream common air duct 12 through which the air that has passed through the first fan 9a flows, and the return air duct 12d through which the return air that has mainly cooled the ice-making chamber 3 and the refrigerating chamber 4 flows. The communication duct 210 is provided with a damper 211 on the inflow side from the upstream common air duct 12, and during the cooling operation, air is prevented from flowing into the communication duct 210. The damper 211 is controlled by one motor provided in the same drive unit 100c as the damper 100. Although the number of dampers has increased compared to Embodiment 1, the increase in the number of motors is suppressed to achieve cost reduction and space saving. The opening area of the damper 211 and the opening area of the opening 212 connecting the communication duct 210 and the return air duct 12d are made larger than the communication hole 200.

[0071] In the refrigerator of Embodiment 2, damper 211 is opened during defrosting using the duct internal circulation fan (defrost operation performed by driving the first fan 9a with dampers 100, 101a, 101b, 102a, and 102b closed). As a result, similar to the communication hole 200, the upstream common air duct 12 and the upstream side of the air flow of the defrost heater 21 are communicated through the communication air duct 210, and a flow path through which the defrost heater 21, the first evaporator 14a, and the first fan 9a can circulate is formed. Specifically, in addition to the air flow shown in FIG. 9, an air flow is formed that flows in the order of the upstream portion 8a1 of the first evaporator chamber where the defrost heater 21 is provided, the first evaporator 14a, the downstream portion 8a2 of the first evaporator chamber, the first fan 9a, the upstream common air duct 12, damper 211, communication air duct 210, opening 212, return air duct 12d, and the upstream portion 8a1 of the first evaporator chamber.

[0072] Here, the refrigerator of Embodiment 2 is provided with damper 211, and by making the openings (damper 211 and opening 212) at the inflow and outflow portions of the communication air duct 210 relatively large (larger than the communication hole 200), the defrosting efficiency of the first evaporator 14a by defrosting using the duct internal circulation fan is further enhanced. In the refrigerator 1 of Embodiment 1, the air of the defrost heater 21 is circulated during defrosting using the duct internal circulation fan through the communication hole 200. However, since the communication hole 200 is not provided with a damper, it cannot be made overly large in order to suppress the amount of air flowing through the communication hole 200 during the cooling operation. On the other hand, Embodiment 2 provides a communication air duct 210 with a larger opening area than the communication hole 200 and is provided with damper 211. During the cooling operation, damper 211 is closed to suppress the influence on the cooling operation, while during defrosting using the duct internal circulation fan, damper 211 is opened so that convective heat transfer from the defrost heater 21 to the first evaporator 14a can be performed at a relatively high air volume and air speed. Therefore, both the cooling operation and the defrost operation can be carried out with high efficiency, and the energy-saving performance can be enhanced.

[0073] In this embodiment, an electric damper 211 whose opening and closing can be controlled by a control board 33, similar to the damper 100, etc., is used. However, since even if a small amount of air flows through the communication air passage 210 during the cooling operation, the influence is small, for example, a damper 211a (not shown) whose opening degree increases when the pressure increases using a spring or the like may be used. During normal cooling operation, one of the dampers 100, 101a, 101b, 102a, 102b is open, while during defrosting using the duct internal circulation fan, all the dampers (100, 101a, 101b, 102a, and 102b) are closed. Therefore, during defrosting using the duct internal circulation fan, the static pressure in the upstream common air passage 12 boosted by the first fan 9a becomes high. As a result, the pressure applied to the damper 211a (not shown) becomes high, and by increasing the opening degree accordingly, a structure can be realized in which the damper opens (the opening degree increases) only during defrosting using the duct internal circulation fan without a motor. Thus, the air flow suppression means provided in the communication air passage 210 may be such that the opening area is small during the cooling operation and large during defrosting using the duct internal circulation fan. Also, since the ability of the air flow suppression means provided in the communication air passage 210 to suppress the air flow may be smaller than that of the air flow control means (dampers 100, 101a, 101b, 102a, and 102b) that controls the air flow to the storage chamber, for example, the opening area of the air flow suppression means during defrosting using the duct internal circulation fan is 1 / 5 or less of the opening area of the air flow control means when fully open and less than the opening area of the air flow control means (dampers 100, 101a, 101b, 102a, and 102b) that controls the air flow to the storage chamber, which is sufficient.

[0074] In addition, in the refrigerator of Embodiment 2, it is also possible to efficiently heat the return air duct 12d. Since the return air duct 12d is where the return air from the ice-making chamber 3 and the freezer compartment 4 with basically low absolute humidity in the freezing temperature zone flows, frost is difficult to grow. However, for example, when the high-humidity air flows into the ice-making chamber 3 and the freezer compartment 4 due to the opening and closing of the ice-making chamber door 3a and the freezer compartment door 4a, there is a possibility that frost will grow in the return air duct 12d. On the other hand, in the defrosting using the duct internal circulation fan of Embodiment 1, it is difficult for the air heated by the defrosting heater 21 to reach the return air duct 12d (see Fig. 9). Also, since the return air duct 12d is not provided above the projection plane of the defrosting heater 21, it is a location where heating is difficult even during fan-stop defrosting by natural convection or radiation. When there is concern about frost growth, it is necessary to provide a dedicated heating heater for the return air duct 12d and heat it with this heater. In contrast, in the refrigerator of Embodiment 2, the air heated by the defrosting heater 21 flows into the return air duct 12d, and heat exchange is performed in a state of high heat transfer by forced convection. Therefore, the return air duct 12d can be heated efficiently, and the heating amount of the dedicated heating heater for the return air duct 12d can be suppressed, or the installation of the dedicated heater can be suppressed.

[0075] Note that the present invention is not limited to the above-described embodiments and includes various modifications. For example, in the above-described embodiments, the damper is provided in the air duct (the connection part between the upstream common air duct 12 and the downstream individual air ducts) as the air supply control means. However, as long as the air supply to the storage compartment can be suppressed as a result of suppressing the air circulation, it may be provided in the air duct returning to the evaporator chamber (before and after the return ports of each storage compartment or the return air duct 12d). Furthermore, it is also conceivable to provide dampers in both the air supply duct and the return air duct to surely suppress the air circulation during defrosting using the duct internal circulation fan.

[0076] In addition, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Furthermore, with respect to a part of the configuration of the above-described embodiments, addition, deletion, or replacement with other configurations is possible. For example, in the refrigerator of the above-described embodiment, a switching chamber (the first switching chamber 5 and the second switching chamber 6) is provided, but a configuration having a freezer compartment or a vegetable compartment, or a configuration having one switching chamber may also be used. Also, although an example has been described in which a plurality of evaporators (the first evaporator 14a and the second evaporator 14b) are provided, a configuration in which all storage compartments are cooled by one evaporator may also be used.

Description of Reference Numerals

[0077] 1: Refrigerator, 2: Refrigerating chamber, 3: Ice-making chamber, 4: Freezing chamber, 5: First switching chamber, 5b: First switching chamber container, 6: Second switching chamber, 6b: Second switching chamber container, 8a: First evaporator chamber, 8a1: Upstream part of the first evaporator chamber, 8a2: Downstream part of the first evaporator chamber, 8b: Second evaporator chamber, 9a: First fan, 9b: Second fan, 12: Upstream common air duct, 12d: Return air duct, 14a: First evaporator, 14b: Second evaporator, 14c: Communication suppression member, 20: Air duct component, 21: Defrosting heater, 24: Compressor, 33: Control board (control unit), 40a: First evaporator temperature sensor, 40b: Second evaporator temperature sensor, 41: Refrigerating chamber temperature sensor, 42: Freezing chamber temperature sensor, 43: First switching chamber temperature sensor, 44: Second switching chamber temperature sensor, 52: Three-way valve, 100: Freezing chamber damper (air flow control means), 100c: Driving part, 101a: First switching chamber damper (air flow control means for freezing mode), 101b: First switching chamber damper (air flow control means for refrigerating mode), 102a: Second switching chamber damper (air flow control means for freezing mode), 102b: Second switching chamber damper (air flow control means for refrigerating mode), 110: Ice-making / freezing chamber air duct (downstream individual air duct), 111a: First switching chamber direct-cooling air duct (downstream individual air duct), 111b: First switching chamber indirect-cooling air duct (downstream individual air duct), 112a: Second switching chamber direct-cooling air duct (downstream individual air duct), 112b: Second switching chamber indirect-cooling air duct (downstream individual air duct), 120a: Ice-making chamber air outlet, 120b: Freezing chamber air outlet, 121a: First switching chamber direct-cooling air outlet, 121b: First switching chamber indirect-cooling air outlet, 122a: Second switching chamber direct-cooling air outlet, 122b: Second switching chamber indirect-cooling air outlet, 130: Ice-making / freezing chamber return port, 131: First switching chamber return port, 132: Second switching chamber return port, 200: Communication hole, 210: Communication air duct, 211: Air flow control damper, 212: Opening

Claims

1. A refrigerator comprising a storage chamber, an evaporator for cooling the storage chamber, an evaporator chamber for housing the evaporator, a fan, an air duct for blowing air from the fan to the storage chamber, a return air duct through which air flows from the storage chamber to the evaporator chamber, air flow control means for controlling the air flow to the storage chamber, and a defrost heater provided in an upstream portion of the evaporator chamber on the upstream side of the air flow of the evaporator for heating the evaporator. A communication portion is provided through which air can circulate among the defrost heater, the evaporator, and the fan without passing through the storage chamber. A first defrost operation in which the defrost heater is energized to heat the evaporator while driving the fan while suppressing the air flow to the storage chamber by the air flow control means. Among the plurality of storage chambers cooled by the evaporator, at least one or more are set to a refrigerating temperature zone, and a third defrost operation in which the defrost heater is energized to heat the evaporator while driving the fan with the air flow control means for controlling the air flow to the storage chamber set to the refrigerating temperature zone being open. Further comprising an outside air temperature sensor for detecting the temperature of the outside air, a storage chamber temperature sensor for detecting the temperature of the storage chamber set to the refrigerating temperature zone, and an evaporator temperature sensor for detecting the temperature of the evaporator. The refrigerator is characterized in that it shifts from the third defrost operation to the first defrost operation based on the temperature detected by the outside air temperature sensor, or the temperature detected by the storage chamber temperature sensor, or the temperature detected by the evaporator temperature sensor.

2. The air duct has an upstream air duct that is a space through which the air that has passed through the fan flows and is partitioned by all of the air flow control means corresponding to the plurality of storage chambers cooled by the evaporator, and a downstream individual air duct through which the air that has passed through each air flow control means flows to each storage chamber. The communication portion communicates the upstream air duct and the upstream portion of the evaporator chamber. The refrigerator according to claim 1, characterized in that.

3. The refrigerator according to claim 2, characterized in that the communication part is provided at the lowermost part of the upstream air duct.

4. The air supply control means corresponding to the storage chamber located at the lowermost position among the plurality of storage chambers cooled by the evaporator is provided below the fan and above the communication part, according to claim 1, characterized in that the refrigerator described.

5. When the first defrosting operation is being performed, air flows along the upstream air duct side separated by all of the air supply control means and reaches the communication part, according to claim 2, characterized in that the refrigerator described.

6. It further includes a second defrosting operation in which power is supplied to the defrosting heater while the fan is stopped, The plurality of storage chambers cooled by the evaporator are, At least one or more can be set to the refrigerating temperature zone, and All can be set to the freezing temperature zone, and When all are set to the freezing temperature zone, after the start of the second defrosting operation, When a predetermined time has elapsed, or when the temperature detected by the evaporator temperature sensor becomes a predetermined temperature or higher, the first defrosting operation is performed, according to claim 1, characterized in that the refrigerator described.

7. When all of the plurality of storage chambers cooled by the evaporator are set to the freezing temperature zone, while suppressing the air supply to any of the storage chambers by all of the air supply control means corresponding to the plurality of storage chambers cooled by the evaporator, the first defrosting operation is performed, according to claim 6, characterized in that the refrigerator described.

8. It further includes a second defrosting operation in which power is supplied to the defrosting heater while the fan is stopped, After the start of the second defrosting operation, when a predetermined time has elapsed, or when the temperature detected by the evaporator temperature sensor becomes a predetermined temperature or higher, it is determined whether to perform the first defrosting operation or the third defrosting operation, according to claim 1, characterized in that the refrigerator described.

9. A refrigerator according to claim 1, further comprising air flow suppression means capable of suppressing air flow in the communication part, separate from the air flow control means, wherein the opening area of the communication part becomes smaller during the cooling operation for cooling the storage chamber by the air flow suppression means, and the opening area of the communication part becomes larger during the first defrosting operation.

10. The air flow path includes an upstream air flow path, which is a space through which the air passing through the fan flows and is partitioned by all of the air flow control means corresponding to the plurality of storage chambers cooled by the evaporator, and a downstream individual air flow path through which the air passing through each of the air flow control means flows to each of the storage chambers. The refrigerator according to claim 1, wherein the communication part communicates the upstream air flow path and the return air flow path.

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