JP2024082068A - refrigerator - Google Patents

Abstract

To provide a refrigerator with high energy-saving performance by suppressing heat exchange in a suction pipe in a refrigerator in which a refrigerator compartment and a freezer compartment are cooled separately.
[Solution] The refrigerator comprises an insulated box, a compressor, a radiator, a three-way valve, a refrigeration evaporator, a freezing evaporator, a refrigeration capillary tube, a freezing capillary tube, a suction pipe, a refrigeration fan, and a freezing fan, and performs a refrigeration operation in which a refrigerant flows through the compressor, the radiator, the three-way valve, the refrigeration capillary tube, the refrigeration evaporator, and the suction pipe in that order while driving the refrigeration fan to cool the refrigerator compartment, and a freezing operation in which a refrigerant flows through the compressor, the radiator, the three-way valve, the refrigeration capillary tube, the refrigeration evaporator, and the suction pipe in that order while driving the refrigeration fan to cool the freezing compartment, in which the suction pipe is arranged in a serpentine manner mainly at the rear of the freezing compartment.
[Selected Figure] Figure 9A

Description

The present invention relates to a refrigerator.

The refrigerant in the refrigeration cycle of a refrigerator is configured to flow through the compressor, radiator, capillary tube, evaporator, and suction pipe in sequence, and then return to the compressor. Here, the capillary tube is capable of exchanging heat with the suction pipe, but since the temperature upstream of the capillary tube is the same as that of the evaporator, there is a possibility that frost may grow depending on the location of the capillary tube. A technology to solve this problem is known in Patent Document 1. For example, claim 2 of Patent Document 1 describes a first cooling mechanism having a "heat-insulated box having a refrigerated temperature zone chamber and a freezer temperature zone chamber, the refrigerated temperature zone chamber and the freezer temperature zone chamber being separated by a heat insulating material, a compressor that discharges the refrigerant, a radiator that radiates heat of the refrigerant to the outside air, a first pressure reducing device that reduces the pressure of the refrigerant, a first cooler that absorbs heat from within the refrigerated temperature zone chamber, and a first suction pipe that is configured to exchange heat with the first pressure reducing device and is embedded in the back of the refrigerated temperature zone chamber, the compressor, the radiator, the second pressure reducing device that reduces the pressure of the refrigerant, and the freezer temperature zone chamber. "The refrigerator is characterized in that a part of the first suction pipe or a part of the second suction pipe is arranged on the rear surface of the refrigerating temperature zone compartment, in which a second cooling mechanism has a second cooler that absorbs heat from the inside of the refrigerating temperature zone compartment, a second suction pipe that is configured to exchange heat with the second pressure reducing device and is embedded in the rear surface of the refrigerating temperature zone compartment, a fan that blows cold air from the first cooler into the refrigerating temperature zone compartment, and an air blowing mechanism that has an air blowing path arranged on the rear surface of the refrigerating temperature zone compartment."

JP 2020-133914 A

Generally, in refrigerators that cool the refrigerator compartment and freezer compartment separately, the evaporation temperature of the refrigerant is higher when cooling the refrigerator compartment (hereafter referred to as refrigeration operation) than when cooling the freezer compartment (hereafter referred to as freezing operation), which increases the cooling efficiency of the heat load of the refrigerator compartment and ultimately improves energy saving performance.

However, in Patent Document 1, this effect is reduced for the following reasons. Because a suction pipe is provided behind the refrigerator compartment cooling air duct provided at the rear of the refrigerator compartment, heat exchange occurs between the refrigerator compartment cooling air duct and the suction pipe. Because a refrigerant with a lower temperature than the freezer compartment flows through the suction pipe upstream of the suction pipe during freezing operation, when heat exchange occurs between the upstream suction pipe and the refrigerator compartment cooling air duct, part of the heat load of the refrigerator compartment is cooled by the suction pipe. As a result, the heat load of the refrigerator compartment that could have been cooled by highly efficient refrigeration operation is instead cooled by less efficient freezing operation, and this difference in efficiency reduces energy-saving performance.

The object of the present invention is to provide a refrigerator that has separate cooling compartments for the refrigerator and freezer, suppresses heat exchange in the suction pipe, and has high energy-saving performance.

In order to solve the above-mentioned problems, the present invention provides a heat-insulating box body formed by filling a space between an inner box and an outer box with a foam insulation material, a compressor, a radiator that dissipates heat from the refrigerant, a three-way valve, a refrigeration evaporator, a freezing evaporator, a refrigeration capillary tube that reduces the pressure of the refrigerant flowing to the refrigeration evaporator, a freezing capillary tube that reduces the pressure of the refrigerant flowing to the freezing evaporator, a suction pipe that returns the refrigerant from the refrigeration evaporator and the freezing evaporator to the compressor and exchanges heat with the refrigeration capillary tube and the freezing capillary tube, a refrigeration fan that blows low-temperature air generated by the refrigeration evaporator into a refrigerator compartment, and a front and a refrigeration fan that blows the low-temperature air generated by the refrigeration evaporator into the freezing chamber, and performs a refrigeration operation in which the refrigeration fan is driven while the refrigerant flows through the compressor, the radiator, the three-way valve, the refrigeration capillary tube, the refrigeration evaporator, and the suction pipe in this order to cool the refrigeration chamber, and a freezing operation in which the refrigeration fan is driven while the refrigerant flows through the compressor, the radiator, the three-way valve, the refrigeration capillary tube, the refrigeration evaporator, and the suction pipe in this order to cool the refrigeration chamber, in which the suction pipe is provided mainly in a serpentine manner on the rear side of the freezing chamber.

The present invention provides a refrigerator with separate cooling compartments for the refrigerator and freezer, which reduces heat exchange in the suction pipe and provides a refrigerator with high energy-saving performance.

FIG. 1 is a front view showing a refrigerator according to an embodiment of the present invention. 2 is a cross-sectional view taken along line AA in FIG. 1 . 3 is a cross-sectional view taken along the line B-B of FIG. 2 . FIG. 2 is a configuration diagram showing a refrigeration cycle of the refrigerator according to the embodiment. 13 is an example of a temperature chart during a cooling operation in the refrigerator according to the embodiment. 5 is a basic control flowchart during cooling operation in the refrigerator according to the embodiment. 13 is an example of a temperature chart during a defrosting operation in the refrigerator according to the present embodiment. 5 is a basic control flowchart during a defrosting operation in the refrigerator according to the present embodiment. 3 is a cross-sectional view taken along the line CC in FIG. 2 , showing the position of the suction pipe of the refrigerator according to the embodiment, in particular showing the positional relationship of the members on the front side (storage chamber side) by dashed lines. 3 is a cross-sectional view taken along the line CC in FIG. 2 , showing the position of the suction pipe of the refrigerator according to the embodiment, in particular showing the positional relationship of the members on the rear side by dashed lines. Cross-sectional view taken along the line D-D of FIG. 9A. FIG. 9B is an enlarged view of the right rear of the E-E cross section of FIG. 9A.

The following describes a form (embodiment) for carrying out the present invention. However, this embodiment is not limited to the following content in any way, and can be modified as desired within the scope that does not detract from the gist of the present invention.

Figure 1 is a front view showing a refrigerator according to this embodiment. In the following explanation, a six-door refrigerator 1 is used as an example, but the refrigerator is not limited to six doors.

As shown in FIG. 1, the insulated box 10 of the refrigerator 1 has storage compartments in the following order from the top: the refrigerator compartment 2, the ice-making compartment 3 on the left and right, the upper freezer compartment 4, the lower freezer compartment 5, and the vegetable compartment 6. The refrigerator 1 is equipped with doors that open and close the openings of each storage compartment. These doors are the left and right divided rotating refrigerator compartment doors 2a and 2b that open and close the opening of the refrigerator compartment 2, and the pull-out ice-making compartment door 3a, the upper freezer compartment door 4a, the lower freezer compartment door 5a, and the vegetable compartment door 6a that open and close the openings of the ice-making compartment 3, the upper freezer compartment 4, the lower freezer compartment 5, and the vegetable compartment 6, respectively. Door hinges (not shown) are provided at the top and bottom of the refrigerator compartment 2 to secure the refrigerator compartment doors 2a and 2b to the refrigerator 1, and the upper door hinge is covered with a door hinge cover 16.

Refrigerator compartment 2 and vegetable compartment 6 are refrigerated storage compartments whose interiors are basically controlled to the refrigeration temperature range (above 0°C); for example, refrigerator compartment 2 is controlled to about 2°C, and vegetable compartment 6 to about 6°C. Ice-making compartment 3, upper freezer compartment 4, and lower freezer compartment 5 are freezer storage compartments whose interiors are controlled to the freezing temperature range (below 0°C), for example, on average around -20°C. In the following, the freezer storage compartments ice-making compartment 3, upper freezer compartment 4, and lower freezer compartment 5 will be referred to as freezer compartment 7.

Figure 2 is a cross-sectional view taken along line A-A in Figure 1. Figure 3 is a cross-sectional view taken along line B-B in Figure 2.

As shown in FIG. 2, the refrigerator 1 is configured such that the outside and inside of the refrigerator are separated by an insulated box 10 formed by filling a space between an outer box 10a (made of steel plate) and an inner box 10b (made of synthetic resin) with a foam insulation material (e.g., urethane foam). In addition to a foam insulation material such as urethane foam, vacuum insulation material 25, which has a lower thermal conductivity than the foam insulation material, is installed between the outer box 10a and the inner box 10b of the insulated box 10, thereby improving the insulation performance without reducing the food storage volume. Here, the vacuum insulation material is composed of a core material such as glass wool or urethane wrapped in an outer packaging material. The outer packaging material contains a metal layer (e.g., aluminum) to ensure gas barrier properties. The vacuum insulation material 25 is arranged on the ceiling wall, left and right walls, back wall, and bottom wall of the insulated box, and vacuum insulation material 25 is also inserted into the door 5a of the lower freezer compartment 5, which is a relatively large freezer storage compartment, to improve the insulation performance.

The refrigerator compartment 2 is separated from the ice-making compartment 3 and the upper freezer compartment 4 by an insulating partition wall 28. The lower freezer compartment 5 and the vegetable compartment 6 are separated by an insulating partition wall 29. In addition, an insulating partition wall 30 is provided on the front side between the ice-making compartment 3, the upper freezer compartment 4, and the lower freezer compartment 5 to prevent air from inside the refrigerator 1 from leaking outside through the gaps in the doors 3a, 4a, and 5a, and to prevent air from outside from entering each storage compartment. In this embodiment, an electric heater (not shown) is provided below the insulating partition wall 29 to heat the vegetable compartment 6 so that the vegetable compartment 6 does not become too cold.

The refrigerator compartment doors 2a, 2b are provided with multiple door pockets 33a, 33b, 33c on the inside of the compartment. The refrigerator compartment 2 is divided into multiple storage spaces by shelves 34a, 34b, 34c, 34d. A low-temperature storage space 36 is provided in the lower part of the refrigerator compartment 2 (above the insulating partition wall 28). The internal storage compartment 35 is kept at a particularly low temperature of about -1 to +1°C, and is a substantially sealed space where no cold air is blown directly into the internal storage compartment 35, and is used to store foods (such as meat and fish) that require prevention of drying at low temperatures.

The ice-making compartment 3, upper freezer compartment 4, lower freezer compartment 5, and vegetable compartment 6 are provided with ice-making compartment container 3b (not shown), upper freezer compartment container 4b, lower freezer compartment container 5b, and vegetable compartment container 6b, which are pulled out together with the doors 3a, 4a, 5a, and 6a, respectively.

The R evaporator 14a, which is a refrigeration evaporator, is housed in the R evaporator chamber 8a, which is a refrigeration evaporator chamber. The R evaporator chamber 8a is formed by the R air passage component 61 provided at the rear of the refrigerator chamber 2 and the inner box 10b. The air in the R evaporator chamber 8a, which has been cooled by heat exchange with the R evaporator 14a, is blown into the refrigerator chamber 2 from the refrigerator chamber outlet 11a provided in the R air passage component 61 by the R fan 9a, which is a refrigeration fan provided above the R evaporator 14a, through the refrigerator chamber air passage 11, and cools the inside of the refrigerator chamber 2. The air blown into the refrigerator chamber 2 returns to the R evaporator chamber 8a from the refrigerator chamber return ports 15a and 15b (see FIG. 3) provided in the R air passage component 61, and is cooled again by the R evaporator 14a.

The refrigerator compartment discharge port 11a is provided mainly at the upper part of the refrigerator compartment 2. The return ports 15a and 15b are provided at the lower part of the refrigerator compartment 2, with the return port 15a being provided at the bottom of the refrigerator compartment 2 (between shelf 34d and the insulating partition wall 28) and approximately at the rear of the internal storage compartment 35, and the return port 15b being provided at the second lowest level of the refrigerator compartment 2 (between shelves 34c and 34d).

The F evaporator 14b, which is a freezing evaporator, is housed in the F evaporator chamber 8b, which is a freezing evaporator chamber. The F evaporator chamber 8b is composed of an F air passage component 62 provided at the rear of the freezing chamber 7 and an inner box 10b. The air in the F evaporator chamber 8b, which has been cooled by heat exchange with the F evaporator 14b, is blown into the freezing chamber 7 from the freezing chamber outlet 12a provided in the F air passage component 62 by the F fan 9b, which is a freezing fan provided above the F evaporator 14b, through the freezing chamber air passage 12, and cools the inside of the freezing chamber 7. The air blown into the freezing chamber 7 returns to the F evaporator chamber 8b from the freezing chamber return port 17 provided in the F air passage component 62, and is cooled again by the F evaporator 14b.

In the refrigerator 1 of this embodiment, the vegetable compartment 6 is also cooled with air cooled by the F evaporator 14b. The air in the F evaporator chamber 8b cooled by the F evaporator 14b is sent to the vegetable compartment 6 by the F fan 9b through the vegetable compartment air duct (not shown) and the vegetable compartment damper (not shown) to cool the inside of the vegetable compartment 6. The low-temperature air generated by the F evaporator 14b is sent to the vegetable compartment 6, but the low-temperature air is prevented from directly entering the vegetable compartment container 6b that stores food, preventing the vegetables from drying out. When the vegetable compartment 6 is at a low temperature, the vegetable compartment damper is closed to prevent the vegetable compartment 6 from being cooled. The air sent to the vegetable compartment 6 returns to the lower part of the F evaporator chamber 8b through the vegetable compartment cold air return duct 18 from the vegetable compartment side cold air return part 18a provided at the lower front of the heat-insulating partition wall 29.

As shown in Figures 2 and 3, a defrost heater 21 for heating the F evaporator 14b is provided at the bottom of the F evaporator chamber 8b. The defrost heater 21 is, for example, a 50W to 200W electric heater, and in this embodiment is a 150W radiant heater. The defrost water (melt water) generated when defrosting the F evaporator 14b falls into the F toy 23b provided at the bottom of the F evaporator chamber 8b, and is discharged into the evaporation dish 32 provided at the top of the compressor 24 via the F drain port 22b and the F drain pipe 27b.

The method of defrosting the R evaporator 14a will be described later using Figures 5 to 8, but the defrosted water generated when defrosting the R evaporator 14a falls into the R drain 23a located at the bottom of the R evaporator chamber 8a, and is discharged into the evaporation tray 32 located in the machine chamber 39 via the R drain outlet (not shown) and the R drain pipe (not shown).

The water discharged into the evaporator dish 32 is heated by the compressor 24 and the heat dissipated by the external radiator 50a, and is vaporized by the air blown by the machine room fan 38 and discharged outside the refrigerator.

The refrigerator compartment 2, freezer compartment 7, and vegetable compartment 6 are provided with a refrigerator compartment temperature sensor 41, a freezer compartment temperature sensor 42, and a vegetable compartment temperature sensor 43 on the rear side of the interior of the refrigerator compartment 2, the freezer compartment 7, and the vegetable compartment 6, respectively. An R evaporator temperature sensor 40a is provided on the top of the R evaporator 14a, and an F evaporator temperature sensor 40b is provided on the top of the F evaporator 14b. These sensors detect the temperatures of the refrigerator compartment 2, the freezer compartment 7, the vegetable compartment 6, the R evaporator 14a, and the F evaporator 14b. In addition, an outside air temperature sensor 37a that detects the temperature of the outside air (outside the refrigerator compartment air) and an outside air humidity sensor 37b that detects the humidity are provided inside the door hinge cover 16 on the ceiling of the refrigerator 1. Other sensors, such as door sensors (not shown) that detect the open/closed state of the doors 2a, 2b, 3a, 4a, 5a, and 6a, are also provided.

A control board 31 (control device, control unit) is arranged in the machine room 39 of the refrigerator 1. The control board 31 is equipped with a CPU, which is part of the control device, memories such as ROM and RAM, an interface circuit, etc. The control board 31 is connected to an outside air temperature sensor 37a, an outside air humidity sensor 37b, a refrigerator compartment temperature sensor 41, a freezer compartment temperature sensor 42, a vegetable compartment temperature sensor 43, an R evaporator temperature sensor 40a, an F evaporator temperature sensor 40b, a door sensor, etc., by electrical wiring (not shown).

The control board 31 controls the compressor 24, R fan 9a, F fan 9b, machine room fan 38, and vegetable room damper based on the output values of each sensor, the settings of the operation unit 26, and programs pre-recorded in the ROM. The operation unit 26 is provided in the inner box 10b inside the refrigerator compartment 2 (see Figure 2), and can be used to adjust the temperatures of the refrigerator compartment 2, freezer compartment 7, and vegetable compartment 6, and to issue instructions to implement additional functions such as a quick-freezing function that increases the cooling capacity of the freezer compartment 7.

Figure 4 is a schematic diagram showing the refrigeration cycle (refrigerant flow path) of the refrigerator according to this embodiment. The refrigerator 1 according to this embodiment includes a compressor 24, an external radiator 50a and a wall surface heat radiation pipe 50b that are heat radiation means for radiating heat from the refrigerant, a condensation prevention pipe 50c that suppresses condensation on the front parts of the heat-insulating partition walls 28, 29, and 30, an R capillary tube 53a (a capillary tube for refrigeration) and an F capillary tube 53b (a capillary tube for freezing) that are pressure reducing means for reducing the pressure of the refrigerant, and an R evaporator 14a and an F evaporator 14b that exchange heat between the refrigerant and the air inside the refrigerator to absorb heat inside the refrigerator, and these are used to cool the inside of the refrigerator. It also includes a dryer 51 that removes moisture in the refrigeration cycle, gas-liquid separators 54a and 54b that prevent liquid refrigerant from flowing into the compressor 24, a three-way valve 52 that controls the refrigerant flow path, a check valve 55 that prevents the refrigerant from flowing back, and a refrigerant junction 56 that joins the refrigerant flow paths. The refrigeration cycle is formed by connecting these with refrigerant piping.

The refrigerator 1 of this embodiment uses isobutane, a flammable refrigerant, as a refrigerant. The compressor 24 of this embodiment is also equipped with an inverter so that the rotation speed can be changed.

The three-way valve 52 has two outlets indicated by 52a and 52b, and is a component capable of switching the outlet through which the refrigerant flows. In addition, the three-way valve 52 of this embodiment can be set to a fully closed state so that no refrigerant flows through either outlet 52a or outlet 52b, or to a double-open state so that the refrigerant flows through both outlets.

In the refrigerator 1 of this embodiment, when the compressor 24 is driven, the refrigerant is compressed, and the high-temperature, high-pressure gas refrigerant dissipates heat while flowing through the external radiator 50a, the wall surface heat dissipation pipe 50b, and the condensation prevention pipe 50c, and becomes liquid refrigerant. This refrigerant flows through the dryer 51 to remove moisture, and then reaches the three-way valve 52. The outlet 52a of the three-way valve 52 is connected to the R capillary tube 53a via the refrigerant pipe, and the outlet 52b is connected to the F capillary tube 53b via the refrigerant pipe.

When the refrigerant flows to the outlet 52a side, the refrigerant flowing out from the outlet 52a is decompressed by the R capillary tube 53, and becomes a low-temperature, low-pressure two-phase refrigerant and reaches the inlet of the R evaporator 14a. The air that returns from the refrigerator compartment 2 to the R evaporator compartment 8a by driving the R fan 9a exchanges heat with the low-temperature refrigerant in the R evaporator 14a as it passes through the R evaporator 14a, becoming colder, and is again blown into the refrigerator compartment 2. At this time, the refrigerant absorbs heat from the air inside the compartment, increasing its enthalpy and its dryness, becoming a nearly saturated gas refrigerant, and reaches the outlet of the R evaporator 14a, passing through the R gas-liquid separator 54a and reaching the refrigerant junction 56.

When the refrigerant flows to the outlet 52b side, the refrigerant flowing out from the outlet 52b is decompressed by the F capillary tube 53b, and becomes a low-temperature, low-pressure two-phase refrigerant and reaches the inlet of the F evaporator 14b. The air returned to the F evaporator chamber 8b from the freezer chamber 7 and the vegetable chamber 6 by the operation of the R fan 9a exchanges heat with the low-temperature refrigerant in the F evaporator 14b as it passes through the F evaporator 14b, becomes cold, and is again blown into the freezer chamber 7 and the vegetable chamber 6. The refrigerant absorbs heat from the air in the chamber, increasing its enthalpy and its dryness, becoming a nearly saturated gas refrigerant and reaching the outlet of the F evaporator 14b, passing through the F gas-liquid separator 54b and the check valve 55 to reach the refrigerant junction 56.

Here, the refrigerant return pipe that returns the refrigerant from the R evaporator 14a and the F evaporator 14b to the compressor 24 is called the suction pipe 57. Furthermore, the part of the suction pipe 57 that connects the R evaporator 14a to the refrigerant junction 56 is called the refrigeration suction pipe 57a, the part that connects the F evaporator 14b to the refrigerant junction 56 is called the freezing suction pipe 57b, and the part that connects the refrigerant junction 56 to the compressor 24 is called the shared suction pipe 57c.

The refrigerant that has passed through the refrigerant junction 56 returns to the compressor 24 via the shared suction pipe 57c, which is located close to the R capillary tube 53a and the F capillary tube 53b so as to exchange heat with them. The refrigerant is heated by the refrigerant in the R capillary tube 53a or the F capillary tube 53b, causing the enthalpy to increase (the temperature to rise), and is sucked back into the compressor 24.

By providing the internal heat exchanger 58, the temperature of the refrigerant sucked into the compressor 24 rises, preventing condensation and frost on the shared suction pipe 57c (see FIG. 7 described later) in the machine room 39, and the enthalpy of the refrigerant flowing into the R evaporator 14a and the F evaporator 14b is reduced by the heat exchange, improving the cooling capacity of the R evaporator 14a and the F evaporator 14b. In addition, due to the relationship between the improvement in cooling capacity and the ratio of the increase in the compression power of the compressor 24, it is possible to expect an improvement in the cooling efficiency (the ratio of the amount of heat cooled to the input of the compressor 24) for refrigerants such as isobutane, that is, an improvement in energy saving performance. Note that the internal heat exchanger 58 only needs to be able to exchange heat between the R capillary tube 53a and the F capillary tube 53b and the shared suction pipe 57c in close proximity, but in this embodiment, the R capillary tube 53a and the F capillary tube 53b are soldered to the shared suction pipe 57c and connected with a metal member to improve the heat exchange efficiency.

Figure 5 is an example of a temperature chart during cooling operation in the refrigerator of this embodiment, and Figure 6 is a basic control flowchart during cooling operation in the refrigerator of this embodiment.

Time t ₀ is the time when the refrigeration operation for cooling the refrigerator compartment 2 is started. In this embodiment, the freezing operation is ended (control S-1), and after the refrigeration operation execution determination (controls S-3 to S-5) and the refrigerant recovery operation (control S-6) described later are performed, the refrigeration operation shown in control S-7 is started. In the refrigeration operation, the three-way valve 52 is set to the outlet 52a side, the compressor 24 is driven to flow the refrigerant to the R evaporator 14a, and the R evaporator 14a is cooled to a low temperature. By operating the R fan 9a in this state, the refrigerator compartment 2 is cooled by the air that has passed through the R evaporator 14a and become low temperature. Here, the temperature of the R evaporator 14a during the refrigeration operation is set higher than that of the F evaporator 14b during the freezing operation described later. In general, the higher the evaporator temperature, the higher the cooling efficiency and the higher the energy saving performance. Therefore, when cooling the refrigerator compartment 2, which can be cooled even at a high evaporator temperature, compared to the freezing compartment 7, which needs to have a low evaporator temperature, the evaporator temperature is increased to improve the energy saving performance. In the refrigerator 1 of this embodiment, the rotation speed of the compressor 24 during refrigeration operation is set to a lower speed (L) than during freezing operation so that the temperature of the R evaporator 14a during refrigeration operation is high.

When the refrigerator compartment 2 is cooled by the refrigeration operation, and the refrigerator compartment temperature detected by the refrigerator compartment temperature sensor 41 drops to T _Roff (control S-8; time t ₁ ), and the freezing operation execution conditions (control S-9) are satisfied, the operation is switched from the refrigeration operation to the refrigerant recovery operation (control S-10). In the refrigerant recovery operation, the compressor 24 is driven with the three-way valve 52 fully closed, and the refrigerant in the R evaporator 14a is recovered. This prevents a refrigerant shortage in the next freezing operation.

When the refrigerant recovery operation is completed (time _t2 ), the operation is switched to the freezing operation for cooling the freezing chamber 7. In the freezing operation, the three-way valve 52 is set to the outlet 52b side, and the refrigerant flows through the F evaporator 14b to lower the temperature of the F evaporator 14b. In addition, the rotation speed of the compressor 24 is set to a higher speed (H) than during the refrigeration operation. By operating the F fan 9b in this state, the freezing chamber 7 is cooled by the air that has passed through the F evaporator 14b and has become cold. This freezing operation is performed until the freezing chamber temperature detected by the freezing chamber temperature sensor 42 becomes T _Foff (time _t5 ). In addition, the vegetable chamber damper (not shown) is also opened during the freezing operation, and the vegetable chamber 6 is cooled until the vegetable chamber temperature detected by the vegetable chamber temperature sensor 43 becomes T _Roff (time _t3 ).

Furthermore, in the refrigerator 1 of this embodiment, after the refrigeration operation is completed, if the R first defrost operation execution judgment (controls S-14, S-16) is satisfied, the first defrost operation of the R evaporator 14a is performed during this refrigerant recovery and freezing operation (hereinafter, R first defrost operation, controls S-18 to S-20). The R first defrost operation is aimed at cooling the refrigerator compartment 2 by the R evaporator 14a, which has become cold during the refrigeration operation, and the frost that has adhered to the R evaporator 14a, and thereby improving the energy saving performance. During the refrigerant recovery operation and the freezing operation, the refrigerant cannot flow through the R evaporator 14a, but the refrigerator compartment 2 can be cooled by the cold storage heat of the R evaporator 14a and the frost that has adhered to the R evaporator 14a. In particular, when the frost on the R evaporator 14a is below 0°C, the refrigeration chamber 2 can be cooled using the heat of melting of the frost, and the refrigeration chamber 2 can be maintained at a low temperature (temperature rise suppressed). This operation suppresses the temperature rise in the refrigeration chamber 2, allowing the freezing operation to be performed for a relatively long time, so the rotation speed of the compressor 24 during the freezing operation can be made relatively slow, improving energy saving performance. Furthermore, by melting the frost on the R evaporator 14a, it is possible to suppress the growth of frost on the R evaporator 14a, reduce the amount of frost to be melted in the R second defrosting operation described below, and suppress the decrease in the heat transfer efficiency of the R evaporator 14a due to frost. In this embodiment, if the number of door openings since the previous first defrosting operation is small, the first defrosting operation is performed, for example, only once every three times (controls S-14 to S-16). This is because if the number of door openings is small and the time interval from the previous first defrosting operation is short, the amount of frost is small, and the above-mentioned cold storage heat effect of the frost and the defrosting effect are small.

This R first defrosting operation ends (control S-20) when the refrigeration evaporator temperature detected by the R evaporator temperature sensor 40a becomes _TDRoff , which is equal to or higher than 0° C. (control S-19; time t ₄ ).

When the end conditions of both the R first defrosting operation and the freezing operation are satisfied (time _t5 ), the three-way valve 52 is again fully closed and the compressor 24 is driven to perform a refrigerant recovery operation (control S-6), recovering the refrigerant in the F evaporator 14b and suppressing a refrigerant shortage in the next refrigeration operation. At this time, the F fan 9b is driven, which allows the residual refrigerant in the F evaporator 14b to be used to cool the freezing chamber 7, and also makes it easier for the refrigerant in the F evaporator 14b to evaporate and reach the compressor 24, allowing a large amount of refrigerant to be recovered in a relatively short time, thereby improving the cooling efficiency.

At time _t6 , the refrigerator returns to the refrigeration operation and repeats the above-mentioned operation. The above is the basic cooling operation of the refrigerator of this embodiment and the first defrost control of the R evaporator 14a. These operations cool the refrigerator compartment 2, the freezer compartment 7, and the vegetable compartment 6 to maintain them at predetermined temperatures, while suppressing the growth of frost on the R evaporator 14a.

Here, a condition is set for switching (time t ₅ ) from freezing operation to refrigeration operation (more precisely, refrigerant recovery before refrigeration operation). As described above, in this embodiment, the operation is switched to refrigeration operation, but before the start of refrigeration operation, judgments of controls S-3 to S-5 are performed. First, it is determined whether the termination conditions of the R-first defrosting operation and the R-second defrosting operation described later in FIG. 10 and subsequent figures are satisfied. If the freezing operation ends before the R-first defrosting operation and the R-second defrosting operation end, the compressor 24 is turned OFF while continuing the R-first defrosting operation and the R-second defrosting operation (control S-3 or S-4 → control S-9 {NO because the freezing operation has ended} → control S-13). During the R-first defrosting operation, the temperature of the R evaporator 14a is relatively low (T _DR <T _DRoff ) and the refrigerator compartment 2 can be cooled, so the compressor 24 is stopped to improve energy saving performance. In addition, the R second defrosting operation described below is intended to discharge the frost adhering to the R evaporator 14a to the outside of the refrigerator, and therefore in order to prevent the defrosted water in the middle of melting from being cooled again and refreezing, the refrigeration operation in which the refrigerant flows through the R evaporator 14a is prohibited during the R second defrosting operation (until the R second defrosting operation is completed). This makes it possible to more reliably defrost the R evaporator 14a.

Also, as shown in control S-5, if the refrigerator compartment temperature _TR is lower than a predetermined value _{TR_start} (for example, _{TR_start} = _TROFF +1°C) at the end of freezing operation (time t5 in FIG. ₅ ), the refrigerator operation is not performed and the compressor 24 is turned OFF. Although not shown, similarly, if the freezer compartment temperature is lower than a predetermined value (for example, T _FOFF +1°C) at the end of freezing operation (time _t1 in FIG. 5), the control S-9 becomes No and the compressor 24 is turned OFF. This makes it possible to prevent excessive cooling inside the refrigerator.

The refrigeration operation starts not only when the freezing operation ends (control S-1), but also when the refrigerator compartment temperature _TR reaches _{TR_start2} (≧ _{TR_start} ) while the compressor 24 is stopped (control S-2). This prevents the refrigerator compartment 2 from becoming too hot when the freezing compartment 7 is sufficiently cold. Although not shown, the freezing operation also starts not only when the refrigeration operation ends, but also when the temperature of the freezing compartment 7 reaches or exceeds a predetermined value.

Next, the defrost control of this refrigerator will be described. Figure 7 is an example of a temperature chart during RF defrost operation in the refrigerator of this embodiment, and Figure 8 is a basic control flowchart during RF defrost operation in the refrigerator of this embodiment. This RF defrost operation is an operation that defrosts both the R evaporator 14a and the F evaporator 14b.

In the refrigerator 1 of this embodiment, during the cooling operation (control S2-1) described in FIG. 5 and FIG. 6, the start of the defrosting operation is determined based on, for example, the number of opening and closing of the doors 2a, 2b, 3a, 4a, 5a, and 6a, the total driving time of the compressor 24, etc. (control S2-2). When the start condition is satisfied (time t _d0 ), the refrigerator 1 of this embodiment performs the freezing operation and the R first defrosting operation (control S2-3). By performing the freezing operation, the melting of frozen foods, ice, etc. due to the temperature rise in the freezer compartment 7 during the RF defrosting operation is suppressed. In addition, during this time, the R first defrosting operation (the R fan 9a is turned ON) is performed to heat the R evaporator 14a and the frost attached to the R evaporator 14a, so that the R second defrosting operation described later is completed in a short time.

After performing this freezing operation for a predetermined time, for example, 30 minutes (time t _d1 ), the refrigerator 1 of this embodiment transitions to RF defrost operation (control S2-4) in which the three-way valve 52 is fully closed, the compressor 24 is turned OFF, the R fan 9a is turned ON, the F fan 9b is turned OFF, and the defrost heater 21 is turned ON. In the RF defrost operation, a defrost operation of the F evaporator 14b shown in controls S2-5 to S2-8 (hereinafter, F defrost operation) and a second defrost operation of the R evaporator 14a shown in controls S2-11 to S2-14 (hereinafter, R second defrost operation) are performed.

First, the control related to the F defrosting operation will be described. By turning off the compressor 24 and the F fan 9b and turning on the defrosting heater 21 (control S2-4), the F evaporator 14b and the frost adhering to the F evaporator 14b are heated by the defrosting heater 21, and the temperature gradually rises. When the temperature reaches or exceeds the melting temperature (0°C), the frost adhering to the F evaporator 14b melts. When the freezing evaporator temperature detected by the F evaporator temperature sensor 40b becomes T _DFoff (for example, 10°C) that is sufficiently higher than the melting temperature of the frost (control S2-5; time t _d2 ), the F defrosting operation is terminated and the defrosting heater 21 is turned off (control S2-6). This causes the F evaporator 14b to be defrosted. After the F defrosting operation is terminated, the system is stopped for, for example, 3 minutes (control S2-7) as a drainage time, and then the freezing operation (control S2-8) is started.

Next, the control related to the R second defrosting operation will be described. Like the R first defrosting operation, the R second defrosting operation is an operation in which the R fan 9a is driven (control S2-4) and the R evaporator 14a and the frost adhering to the R evaporator 14a are heated and defrosted while cooling the refrigerator compartment 2 through heat exchange with the refrigerator compartment 2, which has a higher temperature than the R evaporator 14a. Note that this defrosting method uses only the power (about 1 W) of the R fan 9a to perform defrosting, so the R second defrosting operation is a defrosting method with superior energy saving performance compared to the F defrosting operation in which defrosting is performed using the defrost heater 21 (e.g., 150 W).

When the R second defrosting operation is started, first, it is determined whether the refrigeration evaporator temperature is equal to or higher than T _DROFF (control S2-11). When the refrigeration evaporator temperature T _DR becomes equal to or higher than T _DRoff (e.g., 3°C) (time t _d7 ), a predetermined time Δt _d1 (e.g., 20 minutes) is measured by the timer A (controls S2-12, 13). In the R second defrosting operation, the R evaporator 14a is kept in a state of equal to or higher than T _DRoff (0°C) for a predetermined time Δt _d1 , so that the frost on the R evaporator 14a can be reliably melted and discharged. In addition, air of 0°C or higher can be blown to the R fan 9a and the refrigerator compartment duct 11, which are downstream of the R evaporator 14a, for at least Δt _d1 , so that even if frost has formed on these parts, the frost can be melted. Furthermore, continuing the predetermined time Δt _d1 also has the effect of ensuring the drainage time (control S2-7 in F defrost).

When the refrigeration evaporator temperature T _DR becomes equal to or higher than T _DRoff and the timer A counts a predetermined time Δt _d1 (time t _d2 ), the second defrosting operation is terminated (control S2-14). As described above, the resumption of the cooling operation (freezing operation; control S2-8) is determined only by the F defrosting, and if the R second defrosting operation has not ended, the refrigeration operation is prohibited (control S-4 in FIG. 6 ).

9A and 9B are cross-sectional views taken along the lines C-C in FIG. 2, showing the position of the suction pipe of the refrigerator according to this embodiment. These are basically the same cross-sectional views, but in FIG. 9A, the positional relationship of the members on the front side (storage chamber side) is shown by broken lines, and in FIG. 9B, the positional relationship of the members on the rear side is shown by broken lines. FIG. 10 is a cross-sectional view taken along the lines D-D in FIG. 9A, and FIG. 11 is an enlarged view of the right rear of the cross-sectional view taken along the lines E-E in FIG. 9A. Note that in FIGS. 9A, 9B, and 10, the R capillary tube 53a and the F capillary tube 53b are omitted. Also, since the capillary tubes are in thermal contact with each other at the internal heat exchanger 58, they are sometimes referred to as the shared suction pipe 57c. Of the shared suction pipe 57c, 101 and 102 in FIG. 9A and FIG. 9B are the portions having the soldered internal heat exchanger 58. The arrows in FIG. 9A and FIG. 9B indicate the direction of refrigerant flow during refrigerant circulation.

As shown in FIG. 9A, the common suction pipe 57c equipped with the internal heat exchanger 58 is provided in a serpentine manner mainly at the rear of the freezer compartment 7, particularly at the rear of the F evaporator compartment 8b, and at the front of the vacuum insulation material 25. Note that the rear here refers to the projected surface in the rear direction, and the front here refers to the projected surface in the front direction. Furthermore, in this specification, "serpentine" refers to a state including one or more turns (returns), and the front and rear of the turns do not necessarily have to be parallel to each other.

The shared suction pipe 57c provided on the back of the F evaporator chamber 8b is designed to ensure a distance from the inner box 10b or to minimize the area of proximity. Specifically, if the shared suction pipes 57c provided on the back of the F evaporator chamber 8b are 57c1, 57c2, 57c3, and 57c4 from the top in FIG. 10, a space securing member 111 is provided on the shared suction pipe 57c1 at the top of the F evaporator chamber 8b to ensure a distance between the shared suction pipe 57c1 and the inner box 10b. In this embodiment, the space securing member 111 is provided on the upper end 57c1 of the shared suction pipes 57c1 to 57c4, making it easier to regulate the position of the entire shared suction pipe, but the space securing member 111 may be provided in other places besides 57c1.

In addition, the part of the inner box 10b that divides the rear side of the F evaporator chamber 8b that is located on the rear side of the lower part of the F evaporator 14b is located on the rear side of the basic wall surface of the F evaporator chamber 8b, forming a gap with the F evaporator 14b, and is called the side stage 112. Such space securing member 111 and side stage 112 ensure that the common suction pipe 57c2 and the common suction pipe 57c3 are also spaced apart from the inner box 10b. Here, the distance between the common suction pipe 57c and the inner box 10b is the distance from the front end of the common suction pipe 57c to the rear (rear) of the inner box 10b, but if a part of the capillary tube (F capillary tube 53b in the example of FIG. 11) is located in front of the common suction pipe 57c, it is the distance from the front end of the capillary tube to the rear of the inner box 10b. The shared suction pipe 57c and the capillary tube are both made of metal piping such as copper and are soldered together, so the temperature difference between them is small.

In this embodiment, the distance is about 2 mm except for the side stage 112. When the distance is secured, the gap is filled with foam insulation material, and heat exchange between the shared suction pipe 57c and the inner box 10b is suppressed. This heat exchange suppression effect will be described later. In order to suppress heat exchange between the shared suction pipe 57c1 and the inner box 10b, the space securing member 111 is preferably a material with low thermal conductivity such as a pre-foamed insulation material (e.g., polystyrene foam). In addition, in places where the space securing member 111 is not arranged and the distance between the shared suction pipe 57c and the inner box 10b is secured (for example, between the shared suction pipe 57c2 and the shared suction pipe 57c3 and the inner box 10b in FIG. 10), foam insulation material is filled. In addition, since the foamed urethane foam generally used for the foam insulation material has higher insulation performance than polystyrene foam, it is desirable to make the arrangement range of the space securing member 111 (size in the pipe axial direction) as small as possible if the distance can be reliably secured.

Furthermore, a refrigerant junction 56 is provided above a check valve 55 provided midway through the refrigeration suction pipe 57b. This is because the check valve 55 used in this embodiment needs to be installed so that the refrigerant flows upward, and therefore the refrigerant junction 56 is provided above the check valve 55 so that the refrigerant that passes upward through the check valve 55 reaches the refrigerant junction 56 via the relatively short refrigeration suction pipe 57b.

In addition, in this embodiment, a portion of the suction pipe 57 (refrigeration suction pipe 57a, shared suction pipe 57c) is located at the rear of the refrigerator compartment 2, but the suction pipe 57 is arranged so that it fits behind the R evaporator chamber 8a of the refrigerator compartment 2. The parts of the wall surface of the refrigerator compartment 2 that are close to the suction pipe 57 also become cold inside the compartment, and condensation or frost may occur inside the refrigerator compartment 2. However, even if condensation or frost does occur, this prevents the condensed water or frost from coming into contact with food in the refrigerator compartment 2.

Furthermore, a suction pipe 57 is disposed in the R evaporator chamber 8a, mainly on the rear side of the air flow upstream of the R evaporator 14a (in the flow path from the refrigerator compartment return port 15b to the R evaporator 14a). Even if frost forms on the wall surface in front of the suction pipe 57, air of 0°C or higher from the refrigerator compartment 2 flows over the wall surface before flowing into the R evaporator 14a, so the wall surface is heated by this air and can be melted relatively easily during the R first defrost operation or the R second defrost operation.

In addition, even if water (condensation water or defrost water) occurs on the wall surface of the refrigerator compartment 2 in front of the suction pipe 57, the water is configured to flow to the R toy 23a. In other words, like the defrost water of the R evaporator 14a, the water can be discharged to the machine room 39 via the R toy 23a, the R drain port (not shown), and the R drain pipe 27 (not shown).

In addition, in this embodiment, a space securing member 113 is also provided around the shared suction pipe 57c arranged on the back of the R evaporator chamber 8a so that the distance between the wall surface of the refrigerator chamber 2 and the shared suction pipe 57c can be reliably secured. For this reason, as shown in FIG. 10, in the inner box 10b that defines the back surface of the R evaporator chamber 8a, a portion 114 located in front of the shared suction pipe 57c and the space securing member 113 is shifted toward the front side from the basic back position of the surrounding inner box 10b. In this embodiment, the distance between the inner box 10b and the shared suction pipe 57c is secured to about 2 mm even in the R evaporator 8a. If the distance is secured, the gap is filled with foam insulation, and this thermal resistance prevents the wall surface (inner box 10b) of the refrigerator chamber 2 from becoming cold. In other words, this configuration reduces heat exchange between the wall surface (inner box 10b) of the refrigerator compartment 2 and the suction pipe 57, and prevents the wall surface in front of the suction pipe 57 from becoming too cold, thereby suppressing condensation and frost formation.

In this embodiment, the temperature difference between the refrigerator compartment 2 and the outside air is smaller than that of the freezer compartment 7, so the thickness of the insulating wall of the refrigerator compartment 2 is thinner than that of the freezer compartment 7. As a result, it is difficult to ensure the front-to-rear distance of the shared suction pipe 57c, so the wall surface in front of the shared suction pipe 57c installation area is shifted forward. If the front-to-rear distance of the shared suction pipe 57c can be ensured even at the basic rear position of the refrigerator compartment 2, it is not necessary to shift the wall surface in front of the shared suction pipe 57c installation area forward.

In this embodiment, the distance is 2 mm on the back of the R evaporator 8a, and about 2 mm on the back of the F evaporator chamber 8b excluding the side stage 112, and the gap is filled with foam insulation material, but it is not necessary to fill the gap with foam insulation material, and the insulation effect can be obtained even in an air layer (gas) state, that is, the heat exchange suppression effect between the suction pipe 57 and the refrigerator chamber 2 and the freezer chamber 7 can be obtained. Furthermore, it is desirable to make the distance as long as possible and ensure the insulation thickness, but compared to the case of contact, if a distance of, for example, 0.1 mm is secured, it functions as a contact thermal resistance and the heat exchange suppression effect can be obtained. Note that the space securing members 111, 113 are not limited to those that cover the entire circumference around the axis of the shared suction pipe 57c, and may be provided only on the inside (front) of the shared suction pipe 57c, for example.

The above is the basic structure and control of this refrigerator. Next, we will explain the effects not mentioned above and the detailed effects.

<Effect of suction pipes running along the back of the freezer>
In the refrigerator 1 of this embodiment, as shown in Fig. 9A, the common suction pipe 57c is provided in a serpentine manner mainly on the rear surface of the freezer compartment 7. The reasons and effects of this will be described below.

First, the reason why the common suction pipe 57c is mainly provided on the back side of the freezer compartment 7 will be explained. The refrigerator compartment 2 here includes the R evaporator compartment 8a. The common suction pipe 57c provided on the back side of the refrigerator compartment 2 allows low-temperature refrigerant to flow during freezing operation, so heat exchange occurs between the refrigerator compartment 2 and the common suction pipe 57c, and the refrigerator compartment 2 is cooled. If the heat amount ΔQ of the refrigerator compartment 2 that was cooled during this freezing operation is suppressed, the heat amount ΔQ that was cooled during freezing operation can be cooled by the refrigerator operation, which is more efficient than the freezing operation, and the difference in efficiency improves energy-saving performance. In other words, in a refrigerator in which the refrigerator compartment 2 and the freezer compartment 7 are cooled separately to increase the cooling efficiency of the refrigerator compartment 2, the common suction pipe 57c is provided mainly on the back side of the freezer compartment 7, and the cooling of the refrigerator compartment 2 by the common suction pipe 57c is suppressed, thereby improving energy-saving performance.

The reason why the shared suction pipe 57c is made to snake at the back of the freezer compartment 7 is to ensure the length of the internal heat exchanger 58 while fitting as closely as possible to the back of the freezer compartment 7. By lengthening the internal heat exchanger 58, the amount of heat exchanged per unit time between each capillary tube in the internal heat exchanger 58 and the shared suction pipe 57c can be increased. In other words, the energy saving performance improvement effect of the internal heat exchanger 58 shown in FIG. 4 can be ensured while fitting as closely as possible to the back of the freezer compartment 7.

As described above, by providing the shared suction pipe 57c equipped with the internal heat exchanger 58 in a serpentine shape mainly on the back surface of the freezer compartment 7, it is possible to realize the energy-saving performance improvement effect of the internal heat exchanger 58 while suppressing heat exchange between the shared suction pipe 57c and the refrigerator compartment 2, thereby increasing the proportion of heat cooled during refrigeration operation with high cooling efficiency. In other words, in a refrigerator in which the refrigerator compartment and freezer compartment are cooled separately, it is possible to provide a refrigerator with high energy-saving performance by suppressing heat exchange in the suction pipe.

<Effect on suppressing condensation and frost formation inside the refrigerator>
Furthermore, by suppressing the cooling of the refrigerator compartment 2 by the shared suction pipe 57c, it is also possible to suppress condensation and frost formation in the refrigerator compartment 2. The inside of the refrigerator compartment 2 at the portion of the wall surface thereof that is cooled close to the shared suction pipe 57c also becomes cold, and condensation and frost may occur on this cold wall surface due to moisture inside the refrigerator compartment 2. Therefore, by providing the shared suction pipe 57c mainly on the rear surface of the freezer compartment 7 and suppressing the wall surface of the refrigerator compartment 2 that is cooled by the shared suction pipe 57c, it is possible to suppress the amount of condensation and frost formation.

In addition, as shown in Figures 9A, 9B, and 10, other configurations are also taken into consideration to prevent condensation and frost in the refrigerator compartment 2 of the suction pipe 57. Specifically, the refrigeration suction pipe 57a is arranged to fit behind the R evaporator chamber 8a in the refrigerator compartment 2 so that even if condensation or frost occurs, the condensed water or frost does not come into contact with the food in the refrigerator compartment 2. Also, the refrigeration suction pipe 57a is arranged behind the R evaporator 14a upstream of the air flow in the R evaporator chamber 8a so that frost can be melted relatively easily even if it occurs. Furthermore, even if condensation water or defrost water occurs in front of the location where the refrigeration suction pipe 57a is arranged, the water is discharged into the machine chamber 39. In addition, the front of the location where the shared suction pipe 57c is installed is shifted forward from the basic rear position of the refrigerator compartment 2, and a space-retaining member 113 is provided around the shared suction pipe 57c to prevent the wall surface in front of the shared suction pipe 57c from becoming too cold, thereby suppressing condensation and frost formation.

The above-mentioned effect of suppressing condensation and frost formation in the refrigerator compartment 2 is particularly important in a refrigerator equipped with an R evaporator 14a dedicated to the storage compartment in the refrigeration temperature range, which cools the refrigerator compartment 2 at a higher evaporation temperature than the F evaporator 14b, as shown in FIG. 5. The high evaporation temperature results in less frost (dehumidification) in the R evaporator 14a, and the refrigerator compartment 2 is more likely to become humid than in a refrigerator that cools the refrigerator compartment 2 with the same evaporator as the storage compartment in the freezing temperature range. The high humidity in the refrigerator compartment 2 can suppress the drying of food, but on the other hand, the high dew point makes it easy for condensation and frost to form. Therefore, in a refrigerator equipped with an R evaporator 14a, this configuration is important for suppressing the temperature increase of the wall surface in the refrigerator compartment 2 by the suction pipe 57 and suppressing condensation and frost formation in the refrigerator compartment 2.

As described above, in this embodiment, the cooling of the refrigerator compartment 2 by the suction pipe 57 is suppressed, improving energy saving performance and suppressing condensation and frost formation in the refrigerator compartment 2. As described above, the cooling of the refrigerator compartment 2 by the suction pipe 57 occurs during freezing operation, which leads to a decrease in cooling efficiency, and the refrigerant flowing through the suction pipe 57 is lower in temperature during freezing operation, making condensation and frost more likely to occur. In this embodiment, most of the suction pipes 57 are common suction pipes 57c, which are common refrigerant piping. However, if the refrigeration suction pipes 57a and the freezing suction pipes 57b are longer than the common suction pipes 57c, for example, it is effective to adopt the above-mentioned cooling suppression structure of the refrigerator compartment 2, i.e., a structure that snakes mainly at the back of the freezing compartment 7, for the freezing suction pipes 57b through which the refrigerant flows during freezing operation.

In this specification, "the suction pipes are mainly provided at the rear of the freezer compartment" means that the area of the suction pipes 57 that exceeds 50% of the total length of all suction pipes 57, including the refrigeration suction pipe 57a, the freezing suction pipe 57b, and the shared suction pipe 57c, is positioned at the rear of the freezer compartment 7. Furthermore, when focusing on the freezing suction pipe 57b and the shared suction pipe 57c, which are the parts of the suction pipes through which low-temperature refrigerant flows during freezing operation and which are susceptible to condensation and frost in the refrigerator compartment 2, it is desirable to position an area of at least two-thirds of the total length of these two suction pipes at the rear of the freezer compartment 7.

<Effect of suction pipes meandering mainly behind the refrigeration evaporator chamber>
In this embodiment, the common suction pipe 57c is provided mainly on the rear surface of the freezing chamber 7, and particularly on the rear surface of the F evaporator chamber 8b. The effect of providing the common suction pipe 57c on the rear surface of the F evaporator chamber 8b will be described below.

As explained with reference to FIG. 5, the refrigerator of this embodiment is configured to alternately cool the refrigerator compartment 2 and the freezer compartment 7, so that the freezer compartment 7 cannot be cooled during refrigeration operation in which the refrigerant flows through the R evaporator 14a to cool the refrigerator compartment 2. Therefore, it is necessary to suppress the temperature rise of food in the freezer compartment 7 as much as possible. On the other hand, during refrigeration operation, the temperature of the R evaporator 14a is higher than that of the freezer compartment 7 (see FIG. 5), the suction pipe 57 downstream of the R evaporator 14a is also hotter than the freezer compartment 7, and the temperature of the shared suction pipe 57c rises due to heat exchange with the R capillary tube 53a by the internal heat exchanger 58, so that when heat exchange occurs between the suction pipe 57 and the freezer compartment 7, the freezer compartment 7 is heated. At this time, by making the back surface of the F evaporator chamber 8b of the back surface of the freezer compartment 7 heated, the air in the F evaporator chamber 8b and the F evaporator 14b housed in the F evaporator chamber 8b act as heat storage members, and the effect on the food in the freezer compartment 7 can be suppressed. In other words, by installing the suction pipe 57 on the back surface of the F evaporator chamber 8b, rather than on a wall surface directly exposed to the freezer chamber 7, it is possible to suppress the cooling of the refrigerator chamber 2 as described above while also suppressing the temperature rise of the food in the freezer chamber 7.

<Effects of stopping the freezer fan during refrigeration operation>
During refrigeration operation, the F fan 9b is stopped, suppressing convection between the F evaporator chamber 8b and the freezer chamber 7. This suppresses heat transfer from the F evaporator chamber 8b to the freezer chamber 7 even if the F evaporator chamber 8b is heated, enhancing the effect of the F evaporator chamber 8b as a heat storage member. Furthermore, since convection in the F evaporator chamber 8b is suppressed, the heat transfer coefficient of the back wall of the F evaporator chamber 8b is reduced, and heat exchange between the suction pipe 57 and the back wall of the F evaporator chamber 8b is also suppressed.

<Effects of providing a distance between the suction pipe and the freezer, etc.>
9A, 9B, and 10, a space is provided between the suction pipe 57 and the freezing chamber 7 and the F evaporator 8b by using a space securing member 111 and a side stage 112. This suppresses heat exchange between the suction pipe 57 and the freezing chamber 7 and the F evaporator 14b.

The heating of the freezer compartment 7 and the F evaporator 14b not only increases the temperature of the freezer compartment 7 as described above, but also cools the suction pipe 57, lowering the evaporation temperature and reducing the cooling efficiency. Therefore, suppressing heat exchange between the suction pipe 57 and the freezer compartment 7 and the F evaporator 14b is effective in improving cooling efficiency, i.e., improving energy-saving performance. On the other hand, the decrease in cooling efficiency caused by the cooling of the suction pipe 57 is generally smaller than the difference in cooling efficiency between the refrigeration operation and the freezing operation as described above, and suppressing heat exchange in the refrigerator compartment 2 as described above is more effective in improving energy-saving performance.

In addition, by providing the side stage 112, the frost resistance of the F evaporator 8b can be improved. Since the air from the freezer compartment 7 flows into the F evaporator 8b from the bottom, frost clogging is likely to occur at the bottom, but by using the side stage 112 to allow air to bypass the bottom of the F evaporator 8b, air can be circulated to the top of the F evaporator 8b. In other words, even if frost clogging occurs at the bottom of the F evaporator 8b, cooling can be continued using the top of the F evaporator 8b. By using this side stage 112, it is possible to ensure a separation distance without additional parts while suppressing the decrease in cooling performance due to frost clogging. Furthermore, the position of the side stage 112 is upstream of the F evaporator 14b in the air flow, and since air before being cooled by the F evaporator 14b flows through it, it is a place where relatively high-temperature air flows in the F evaporator 8b. Therefore, even if the side stage 112 and the suction pipe 57 on its back are close to each other, the temperature difference between the side stage 112 and the suction pipe 57 is relatively small, and heat exchange can be kept relatively small.

As described above, the refrigerator of this embodiment suppresses heating of the freezer compartment 7 by the suction pipe 57, suppresses the temperature rise of food in the freezer compartment 7, and improves energy saving performance. As described above, the heating of the freezer compartment 7 by the suction pipe 57 is more likely to occur during refrigeration operation because the refrigerant flowing through the suction pipe 57 is at a higher temperature, and heat exchange is more likely to occur. In addition, as for the food in the freezer compartment 7, the temperature rise of the food during refrigeration operation, which cannot cool the freezer compartment 7, is a problem. In this embodiment, most of the suction pipes 57 are common suction pipes 57c, which are common refrigerant piping. However, if the refrigeration suction pipes 57a and the freezing suction pipes 57b are longer than the common suction pipes 57c, for example, it is effective to adopt the above-mentioned heating suppression structure for the freezer compartment 7, i.e., the space securing member 111 and the side stage 112, for the refrigeration suction pipes 57a through which the refrigerant flows during refrigeration operation.

<Effect of having vacuum insulation material located behind the suction pipe>
Furthermore, in this embodiment, the heat exchange between the suction pipe 57 and the outside of the refrigerator is also taken into consideration. Specifically, as shown in Figs. 9A and 9B, the suction pipe 57 is mainly arranged in front of the vacuum insulation material 25. Here, if the suction pipe 57 is close to the outer box 10a, heat exchange occurs between the suction pipe 57 and the outside of the refrigerator through the outer box 10a, the suction pipe 57 is heated by the heat from the outside of the refrigerator, and the heat load to be cooled by the refrigeration cycle increases. In particular, since the upstream side of the suction pipe 57 is at a low temperature close to the evaporation temperature, the amount of heat exchange may be greater than the heat exchange between the storage chamber and the outside of the refrigerator. In contrast, in this embodiment, the vacuum insulation material 25 is arranged between the suction pipe 57 and the back wall (outer box 10a) to suppress this heat exchange. In addition, by arranging the suction pipe 57 on the back surface of the freezer compartment 7, the distance between the ceiling wall, side wall and bottom wall and the suction pipe 57 is ensured, i.e., the insulation thickness provided by the insulating foam material is ensured, so that heat exchange between the ceiling wall, side wall and bottom wall and the suction pipe 57 is reduced.

In addition, due to the degree of freedom in the shape of the vacuum insulation material and the manufacturability of the refrigerator, it is generally difficult to arrange the vacuum insulation material in the corner between the rear wall and the side wall of the refrigerator. Therefore, if the suction pipe 57 is arranged in the corner of the refrigerator, the heat exchange with the outside is likely to increase (insulation by the vacuum insulation material 25 is difficult). However, in this embodiment, the suction pipe 57 is mainly provided on the rear of the freezer chamber 7, so that the suction pipe 57 is not arranged in the corner of the refrigerator. Specifically, the shortest distance (length L2 in FIG. 11) between the upstream side of the suction pipe 57, which is relatively low temperature (upstream side of the refrigerant flow from the middle between 101 and 102 in FIG. 9A and FIG. 9B) and the ceiling wall, side wall, and rear wall without the vacuum insulation material 25 between them is longer than the shortest distance (length L3 in FIG. 11) between the refrigerator chamber 2 and the freezer chamber 7 and the ceiling wall, side wall, and flat wall without the vacuum insulation material 25 between them.

<Effects of shared suction pipe>
9A and 9B, in this embodiment, the common suction pipe 57c is longer than the refrigeration suction pipe 57a on the R evaporator 14a side and the freezing suction pipe 57b on the F evaporator 14b side, and the common suction pipe 57c is provided with an internal heat exchanger 58. One reason for this is to reduce the cost of resources and materials used for the refrigerant piping by sharing the refrigerant piping as much as possible. Another reason is to ensure both the distance of the internal heat exchanger 58 and the freedom of installation. If the refrigeration suction pipe 57a and the freezing suction pipe 57b are each provided with an internal heat exchanger 58, a refrigerant piping length is required to ensure the length of the internal heat exchanger 58, which reduces the freedom of installation and makes it difficult to accommodate them on the back side of the freezer chamber 7 or in front of the vacuum insulation material 25. In response to this, by providing an internal heat exchange section 58 in the shared suction pipe 57c, which is used in common, it is possible to ensure the length of the internal heat exchange section 58 while fitting it as closely as possible to the rear surface of the freezer compartment 7 and the front surface of the vacuum insulation material 25.

The present invention is not limited to the above-described embodiment, but includes various modified examples. For example, the above-described embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to having all of the configurations described. In addition, it is possible to add, delete, or replace part of the configuration of the above-described embodiment with other configurations.

1...refrigerator, 2...refrigeration compartment, 3...ice-making compartment, 4...upper freezer compartment, 5...lower freezer compartment, 6...vegetable compartment, 8a...R evaporator compartment (evaporator compartment for refrigeration), 8b...F evaporator compartment (evaporator compartment for freezing), 9a...R fan (fan for refrigeration), 9b...F fan (fan for freezing), 10...insulated box, 10a...outer box, 10b...inner box, 11...refrigerator compartment air duct, 11a...refrigerator compartment outlet, 12...freezer compartment air duct, 12a...freezer compartment outlet, 14a...R evaporator ( refrigeration evaporator), 14b...F evaporator (freezing evaporator), 15a, 15b...refrigeration compartment return port, 16...hinge cover, 18...vegetable compartment return air duct, 18a...vegetable compartment return port, 21...radiant heater, 22b...drain port, 23a...R toy, 23b...F toy, 24...compressor, 25...vacuum insulation material, 26...operation unit, 27b...F drain pipe, 28, 29, 30...insulating partition wall, 32...evaporation dish, 34a, 34b, 34c, 34d...shelf, 3 5... Internal storage compartment, 38... Machine compartment fan, 39... Machine compartment, 40a... R evaporator temperature sensor, 40b... F evaporator temperature sensor, 41... Refrigerator compartment temperature sensor, 42... Freezer compartment temperature sensor, 43... Vegetable compartment temperature sensor, 50a... External radiator (heat dissipation means), 50b... Wall surface heat dissipation piping (heat dissipation means), 50c... Condensation prevention piping (heat dissipation means), 51... Dryer, 52... Three-way valve (refrigerant control means), 53a... R capillary tube (pressure reduction means) ), 53b...F capillary tube (pressure reducing means), 54b...R gas-liquid separator, 54b...F gas-liquid separator, 55...check valve, 56...refrigerant junction, 57...suction pipe, 57a...refrigerating suction pipe, 57b...freezing suction pipe, 57c...shared suction pipe, 58...internal heat exchanger, 61...R air passage component, 62...F air passage component, 111, 113...space securing member, 112...side stage

Claims (9)

the refrigeration system includes an insulated box body formed by filling a space between an inner box and an outer box with a foam insulation material, a compressor, a radiator for radiating heat from a refrigerant, a three-way valve, a refrigeration evaporator, a freezing evaporator, a refrigeration capillary tube for reducing the pressure of the refrigerant flowing to the refrigeration evaporator, a freezing capillary tube for reducing the pressure of the refrigerant flowing to the freezing evaporator, a suction pipe for returning the refrigerant from the refrigeration evaporator and the freezing evaporator to the compressor and exchanging heat with the refrigeration capillary tube and the freezing capillary tube, a refrigeration fan for blowing low-temperature air generated by the refrigeration evaporator into a refrigeration chamber, and a freezing fan for blowing low-temperature air generated by the refrigeration evaporator into a freezing chamber,
a refrigerator that performs a refrigeration operation in which the refrigeration fan is driven while the refrigerant flows through the compressor, the radiator, the three-way valve, the refrigeration capillary tube, the refrigeration evaporator, and the suction pipe in this order, to cool the refrigeration compartment; and a freezing operation in which the refrigeration fan is driven while the refrigerant flows through the compressor, the radiator, the three-way valve, the refrigeration capillary tube, the refrigeration evaporator, and the suction pipe in this order, to cool the freezing compartment,
The refrigerator is characterized in that the suction pipe is provided mainly in a serpentine manner on the rear surface of the freezer compartment. Further comprising a refrigeration evaporator chamber for accommodating the refrigeration evaporator,
2. The refrigerator according to claim 1, wherein the suction pipe is provided in a serpentine manner mainly on the back surface of the refrigeration evaporator chamber. The refrigerator according to claim 2, characterized in that the freezing fan is stopped during the refrigeration operation. The refrigerator according to claim 1, characterized in that a vacuum insulation material is located on the back side of the suction pipe. In the suction pipe, a portion connecting the refrigeration evaporator to the refrigerant junction is called a refrigeration suction pipe, a portion connecting the refrigeration evaporator to the refrigerant junction is called a refrigeration suction pipe, and a portion connecting the refrigerant junction to the compressor is called a shared suction pipe.
5. The refrigerator according to claim 1, wherein the common suction pipe is longer than the refrigeration suction pipe and the freezing suction pipe, and exchanges heat with the refrigeration capillary tube and the freezing capillary tube. Further comprising a refrigeration evaporator chamber for accommodating the refrigeration evaporator,
5. The refrigerator according to claim 1, wherein a part of the suction pipe is located at a rear surface of the refrigerating evaporator chamber and upstream of the air flow of the refrigerating evaporator. The refrigerator according to any one of claims 1 to 4, characterized in that a space-retaining member is located between the inner box and the suction pipe, in addition to the foam insulation material. The refrigerator according to claim 7, characterized in that the portion of the inner box located in front of the space securing member is located further forward than the surrounding inner box. A side stage is provided in the inner box on the rear side of the refrigeration evaporator and on the upstream side of the air flow of the refrigeration evaporator to form a gap with the refrigeration evaporator,
8. The refrigerator according to claim 7, wherein the suction pipe is located on a rear surface of the side stage.

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