refrigerator

Abstract

To use the same refrigerant piping in a defrosting operation and a cooling operation in a refrigerator having the defrosting operation for heating a refrigerating evaporator by a high temperature refrigerant while utilizing cooling of a refrigerating chamber as heat absorption.SOLUTION: The refrigerant discharged from the compressors 24 flows through the first refrigerant control portion 101, the heat radiation portion 50, the second refrigerant control portion 52, the first decompression portion 53b, the freezing vaporizer 14b, the third refrigerant control portion 112, and the first branch portion 56 in this order and returns to the compressors 24. In the defrosting operation, the refrigerant discharged from the compressors 24 flows through the first refrigerant controller 101, the first evaporator 14b, and the second evaporator 14b in this order and returns to the compressors 24, and the refrigerant passage for heat-exchanging with the first evaporator 14a in the defrosting operation and the refrigerant passage for heat-exchanging with the second evaporator 14b in the refrigerating operation are formed by the same refrigerant pipes FP5b, FP5c, and FP5d. 14b.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Patent Document 1 describes the following (1) and (2): (1) A high-pressure, high-temperature refrigerant compressed by a compressor flows through a defrosting pipe provided in the refrigeration cooler and exchanges heat with frost adhering to the refrigeration cooler, melting the frost and cooling the high-pressure, high-temperature refrigerant to a liquid state (see paragraph 0047). (2) During defrosting operation, the control unit rotates the refrigeration fan at a predetermined rotation speed to perform refrigeration operation to cool the refrigerator compartment and vegetable compartment in the refrigeration temperature range. That is, during defrosting operation, the high-pressure, high-temperature liquid refrigerant flowing out of the defrosting pipe flows into the refrigeration cooler via the dryer, the cooling switching valve, and the refrigeration pressure reducing device (see paragraph 0048). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-215147 Summary of the Invention [Problem to be solved by the invention]

[0004] The refrigerator in Patent Document 1 is equipped with a defrosting operation in which a high-temperature refrigerant from the compressor heats a freezing evaporator used to cool the freezer compartment, and the refrigerant flows into a refrigeration evaporator used to cool the refrigerator compartment. By cooling the refrigerator compartment in the defrosting operation, the thermal load on the refrigerator compartment can be reduced, and this heat absorption acts as a heat pump and serves as a heat source during defrosting, reducing the power consumed during defrosting (power input to the compressor). Cooling the refrigerator compartment in this way improves energy-saving performance.

[0005] A main object of the present invention is to provide a refrigerator that has a defrosting operation in which a freezing evaporator is heated with a high-temperature refrigerant while utilizing the cooling of a refrigerator compartment as heat absorption, and that exchanges heat with the freezing evaporator using the same refrigerant piping during both the defrosting operation and the cooling operation. [Means for solving the problem]

[0006] In order to achieve the above object, the refrigerator of the present invention comprises: A refrigerator compartment and a refrigeration evaporator for cooling the refrigeration compartment; A freezer and a refrigeration evaporator for cooling the freezing compartment; a compressor that compresses a refrigerant; a heat dissipation unit that dissipates heat from the refrigerant; a first pressure reducing section and a second pressure reducing section that reduce the pressure of the refrigerant; a first branch portion provided in the refrigerant flow path; a first refrigerant control unit, a second refrigerant control unit, and a third refrigerant control unit that perform at least one of switching and closing of the refrigerant flow path; In a freezing and cooling operation for cooling the freezing compartment, a refrigerant flow path is configured so that the refrigerant discharged from the compressor flows in the order of the first refrigerant control unit, the heat radiating unit, the second refrigerant control unit, the first decompression unit, the freezing evaporator, the third refrigerant control unit, and the first branch unit, and returns to the compressor to cool the freezing evaporator, In a defrosting operation for melting frost on the freezing evaporator, the third refrigerant control unit closes a refrigerant flow path that bypasses the refrigeration evaporator from the freezing evaporator and returns to the compressor, and the refrigerant flow path is configured so that the refrigerant discharged from the compressor flows through the first refrigerant control unit, the freezing evaporator, and the refrigeration evaporator in this order, and returns to the compressor, thereby heating the freezing evaporator. The refrigerant flow path that exchanges heat with the freezing evaporator in the defrosting operation and the refrigerant flow path that exchanges heat with the freezing evaporator in the freezing / cooling operation are configured by the same refrigerant piping. [Brief explanation of the drawings]

[0007] [Figure 1]1 is a front view showing the configuration of a refrigerator according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III shown in FIG. 2. [Figure 4A] 1 is a perspective view showing the configuration of a refrigeration evaporator and its surroundings in the refrigerator of the first embodiment. FIG. [Figure 4B] FIG. 2 is a diagram showing the internal configuration of a refrigeration gas-liquid separator in the refrigerator of the first embodiment. [Figure 5] 1 is a schematic diagram showing the configuration of a refrigeration cycle (refrigerant flow path) in a refrigerator of a first embodiment. [Figure 6A] FIG. 2 is an explanatory diagram showing the flow of refrigerant during refrigeration cooling operation in the refrigerator of the first embodiment. [Figure 6B] FIG. 2 is an explanatory diagram showing the flow of refrigerant during freezing and cooling operation in the refrigerator of the first embodiment. [Figure 6C] FIG. 3 is an explanatory diagram showing the flow of refrigerant during a defrosting operation in the refrigerator of the first embodiment. [Figure 7] FIG. 1 is a Ph diagram showing the state of the refrigeration cycle during defrosting operation. [Figure 8] FIG. 4 is a schematic diagram showing the configuration of a refrigeration cycle (refrigerant flow path) in a comparative example. [Figure 9A] 1 is a schematic diagram showing a first modification of the refrigeration cycle (refrigerant flow path) of the first embodiment. [Figure 9B] 10 is a schematic diagram showing a second modification of the refrigeration cycle (refrigerant flow path) of the first embodiment. FIG. [Figure 10] FIG. 10 is a schematic diagram showing the configuration of a refrigeration cycle (refrigerant flow path) in a refrigerator according to a second embodiment. [Figure 11A] FIG. 10 is a schematic diagram showing a first modification of the refrigeration cycle (refrigerant flow path) of the second embodiment. [Figure 11B] FIG. 10 is a schematic diagram showing a second modification of the refrigeration cycle (refrigerant flow path) of the second embodiment. [Figure 11C] 10 is a schematic diagram showing a third modification of the refrigeration cycle (refrigerant flow path) of the second embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail with reference to the drawings. Note that each drawing is merely a schematic illustration to allow a sufficient understanding of the present invention. Therefore, the present invention is not limited to the illustrated examples. Furthermore, in each drawing, common or similar components are given the same reference numerals, and redundant explanations thereof will be omitted.

[0009] [Example 1] <Overall configuration of refrigerator 1> The configuration of refrigerator 1 of Example 1 will be described below with reference to Figs. 1 to 3. Fig. 1 is a front view showing the configuration of refrigerator 1 of Example 1. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2. In the following description, a six-door refrigerator 1 will be used as an example, but the refrigerator 1 is not limited to six doors.

[0010] The refrigerator 1 has the function of performing refrigeration / cooling operation, freezing / cooling operation, and defrosting operation. The refrigeration / cooling operation is an operation in which a low-temperature, low-pressure refrigerant that has passed through the capillary tube 53a evaporates in the refrigeration evaporator 14a to cool a storage compartment (for example, the refrigeration compartment 2 (FIG. 1)). The freezing / cooling operation is an operation in which a storage compartment (for example, the freezer compartment 7 (FIG. 1)) is cooled by the freezing evaporator 14b. The defrosting operation is an operation in which frost that has adhered to the freezing evaporator 14b (FIGS. 2 and 3) is removed.

[0011] As shown in FIG. 1, the insulated box 10 of the refrigerator 1 has, from the top to the bottom, a refrigerator compartment 2, an ice-making compartment 3 on either side, an upper freezer compartment 4, a lower freezer compartment 5, and a vegetable compartment 6. The refrigerator 1 is equipped with doors that open and close the openings of each storage compartment. These doors consist of left and right divided rotating refrigerator compartment 2 doors 2a and 2b that open and close the opening of the refrigerator compartment 2, and pull-out ice-making compartment 3 door 3a, upper freezer compartment 4 door 4a, lower freezer compartment 5 door 5a, and vegetable compartment 6 door 6a that open and close the openings of the ice-making compartment 3, upper freezer compartment 4, lower freezer compartment 5, and 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 2 doors 2a and 2b to the refrigerator 1, and the upper door hinge is covered with a door hinge cover 16.

[0012] Refrigerator compartment 2 and vegetable compartment 6 are refrigerated storage compartments that basically control the interior of the compartment to a refrigerated temperature range (above 0°C); for example, refrigerator compartment 2 is controlled to about 4°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 that control the interior of the compartment to a freezer temperature range (below 0°C), for example, about -20°C on average. Note that ice-making compartment 3, upper freezer compartment 4, and lower freezer compartment 5, which are freezer storage compartments, may be referred to as freezer compartment 7.

[0013] As shown in FIG. 2, the refrigerator 1 is configured such that the interior and exterior 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 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 to improve insulation performance without reducing food storage capacity. The vacuum insulation material 25 is formed by wrapping a core material such as glass wool in an outer packaging material. The outer packaging material contains a metal layer (e.g., aluminum) to ensure gas barrier properties. Vacuum insulation material 25 is arranged on the ceiling wall, left and right walls, back wall, and bottom wall of the insulated box 10. It is also inserted into the door 5a of the lower freezer compartment 5, a relatively large freezer storage compartment, to improve insulation performance.

[0014] The refrigerator compartment 2 is separated from the ice making compartment 3 and upper freezer compartment 4, which are adjacent to the refrigerator compartment 2 below, by an insulating partition wall 28. The lower freezer compartment 5 and 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, upper freezer compartment 4, and lower freezer compartment 5 to prevent air from leaking from inside the refrigerator 1 to the outside through gaps in the doors 3a, 4a, and 5a, and to prevent air from outside from entering each storage compartment. In Example 1, an electric heater (not shown) is provided below the insulating partition wall 29 to heat the vegetable compartment 6 so that the temperature in the vegetable compartment 6 does not become excessively low.

[0015] Doors 2a and 2b of refrigerator compartment 2 are provided with multiple door pockets 33a, 33b, and 33c on the inside. Refrigerator compartment 2 is divided into multiple storage spaces by shelves 34a, 34b, 34c, and 34d. A low-temperature storage space 35 is provided in the lower part of refrigerator compartment 2 (above heat-insulating partition wall 28). Low-temperature storage space 35 is also called internal storage compartment 35. Internal storage compartment 35 is kept at an especially low temperature of about -1 to +1°C, within refrigerator compartment 2, and is configured as a substantially sealed space to which no cold air is blown directly. This space is used to store foods (such as meat and fish) that require special attention to prevent drying at low temperatures.

[0016] The ice making compartment 3, upper freezer compartment 4, lower freezer compartment 5, and vegetable compartment 6 are provided with an ice making compartment container, an upper freezer compartment container 4b, a lower freezer compartment container 5b, and a vegetable compartment container 6b, which are pulled out together with the doors 3a, 4a, 5a, and 6a, respectively.

[0017] The refrigeration evaporator 14a is housed in the refrigeration evaporator chamber 8a. The refrigeration evaporator chamber 8a is formed by an inner box 10b and a refrigeration chamber air-path component 61 provided at approximately the rear of the refrigeration chamber 2. The air in the refrigeration evaporator chamber 8a, which has been cooled by heat exchange with the refrigeration evaporator 14a, is blown into the refrigeration chamber 2 from a refrigeration chamber outlet 11a provided in the refrigeration chamber air-path component 61 by a refrigeration fan 9a provided above the refrigeration evaporator 14a via the refrigeration chamber air-path 11, thereby cooling the interior of the refrigeration chamber 2. The air blown into the refrigeration chamber 2 returns to the refrigeration evaporator chamber 8a from refrigeration chamber return ports 15a, 15b (FIG. 3) provided in the refrigeration chamber air-path component 61 and is cooled again by the refrigeration evaporator 14a.

[0018] Refrigerating compartment discharge port 11a is provided mainly in the upper part of refrigerating compartment 2. Refrigerating compartment return ports 15a and 15b are provided in the lower part of refrigerating compartment 2, with refrigerating compartment return port 15a being provided on the lowest level of refrigerating compartment 2 (between shelf 34d and heat insulating partition wall 28) and approximately at the rear of internal storage compartment 35, and refrigerating compartment return port 15b being provided on the second level from the bottom of refrigerating compartment 2 (between shelf 34c and shelf 34d).

[0019] The freezing evaporator 14b is housed in the freezing evaporator chamber 8b. The freezing evaporator chamber 8b is composed of a freezing chamber air-passage component 62 provided at approximately the rear of the freezing chamber 7 and an inner box 10b. The air in the freezing evaporator chamber 8b, which has been cooled by heat exchange with the freezing evaporator 14b, is blown into the freezing chamber 7 from a freezing chamber outlet 12a provided in the freezing chamber air-passage component 62 by a freezing fan 9b provided above the freezing evaporator 14b through the freezing chamber air-passage 12, thereby cooling the freezing chamber 7. The air blown into the freezing chamber 7 returns to the freezing evaporator chamber 8b from a freezing chamber return port 17 provided in the freezing chamber air-passage component 62 and is cooled again by the freezing evaporator 14b.

[0020] In the refrigerator 1 of Example 1, the vegetable compartment 6 is also cooled with air cooled by the freezing evaporator 14b. The air in the freezing evaporator chamber 8b cooled by the freezing evaporator 14b is blown into the vegetable compartment 6 by the freezing fan 9b through a vegetable compartment air duct (not shown) and a vegetable compartment damper (not shown), cooling the vegetable compartment 6. Although the low-temperature air generated by the freezing evaporator 14b is blown into the vegetable compartment 6, 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 cold, the vegetable compartment damper is closed to prevent the vegetable compartment 6 from being cooled. The air blown into the vegetable compartment 6 returns to the bottom of the freezing evaporator 14b through the vegetable compartment-side cold air return vent 18a located at the bottom of the insulating partition wall 29 and the vegetable compartment cold air return duct 18.

[0021] When moisture-laden air flows into the refrigerator due to the opening and closing of the door, and flows into the low-temperature refrigeration evaporator 14a and freezing evaporator 14b from the refrigerator compartment return ports 15a and 15b, the freezer compartment return port 17, and the vegetable compartment cold air return air duct 18, the moisture in the air turns into frost and adheres to the surfaces of the evaporators 14a and 14b. As the frost grows, it impedes the heat exchange between the evaporators and the air, and the amount of air flowing through the evaporators decreases due to the ventilation resistance caused by the frost, so the refrigerator 1 performs a defrosting operation to melt the frost on the evaporators 14a and 14b.

[0022] The defrosted water (melted water) generated during defrosting of the freezing evaporator 14b falls into the freezing chamber drain 23b located at the bottom of the freezing evaporator chamber 8b, and is discharged into the evaporator dish 32 located above the compressor 24 via the freezing chamber drain outlet 22b and the freezing chamber drain pipe 27b.

[0023] The refrigeration evaporator 14a performs defrosting by off-cycle defrosting, which circulates the air from the refrigeration compartment 2 to the refrigeration evaporator 14a and defrosts using the heat from the refrigeration compartment 2. The defrosted water generated during defrosting of the refrigeration evaporator 14a falls into the refrigeration compartment drain 23a provided at the bottom of the refrigeration evaporator compartment 8a, and is discharged into the evaporator tray 32 provided in the machine compartment 39 via a refrigeration compartment drain outlet (not shown) and a refrigeration compartment drain pipe (not shown).

[0024] The water discharged into the evaporation dish 32 is heated by heat radiation from the compressor 24 and the external radiator 50a, and is vaporized by air blown by the machine room fan 38, and is discharged outside the refrigerator.

[0025] A refrigerator compartment temperature sensor 41, a freezer compartment temperature sensor 42, and a vegetable compartment temperature sensor 43 are provided on the rear side of the refrigerator compartment 2, freezer compartment 7, and vegetable compartment 6, respectively. A refrigerator evaporator temperature sensor 40a is provided above refrigerator evaporator 14a, and a freezer evaporator temperature sensor 40b is provided above freezer evaporator 14b. These sensors detect the temperatures of refrigerator compartment 2, freezer compartment 7, vegetable compartment 6, refrigerator evaporator 14a, and freezer evaporator 14b. An outside air temperature sensor 37a that detects the temperature of outside air (outside the refrigerator) and an outside air humidity sensor 37b that detects humidity are also provided inside door hinge cover 16 on the ceiling of refrigerator 1. Other sensors include door sensors (not shown) that detect the open / closed states of doors 2a, 2b, 3a, 4a, 5a, and 6a.

[0026] A control board 31 (control device, control section) equipped with a CPU (Central Processing Unit), which is part of the control device, memories such as ROM (Read Only Memory) and RAM (Random Access Memory), an interface circuit, etc. is disposed in the machine compartment 39 of the refrigerator 1. 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, a refrigerator evaporator temperature sensor 40a, a freezer evaporator temperature sensor 40b, and each door sensor, etc., by electrical wiring (not shown).

[0027] Furthermore, control board 31 controls compressor 24, refrigeration fan 9a, freezer fan 9b, machine compartment fan 38, and vegetable compartment damper based on the output values ​​of each sensor, the settings of operation unit 26, and programs pre-recorded in ROM. Operation unit 26 is provided in inner box 10b inside refrigerator compartment 2 (Fig. 2), and operation unit 26 can be used to adjust the temperatures of refrigerator compartment 2, freezer compartment 7, and vegetable compartment 6, as well as to issue instructions to implement additional functions such as a quick-freezing function that increases the cooling capacity of freezer compartment 7.

[0028] <Configuration of refrigeration evaporator 14b> The configuration of the refrigeration evaporator 14b will be described below with reference to Fig. 4A and Fig. 4B. Fig. 4A is a perspective view showing the configuration around the refrigeration evaporator 14b. Fig. 4B is a view showing the internal configuration of the refrigeration gas-liquid separator 54b in the refrigerator 1 of the first embodiment. The refrigeration evaporator 14b of the first embodiment shown in Fig. 4A and Fig. 4B is a general evaporator that is also used in refrigerators that use an electric heater for defrosting.

[0029] The refrigerant pipe 59 of the freezing evaporator 14b is a refrigerant pipe downstream of the freezing capillary tube 53b shown in FIG. 5, extending from the refrigerant inlet of the freezing evaporator 14b to the refrigerant outlet of the freezing gas-liquid separator 54b. In this embodiment, the direction of the refrigerant flowing through the freezing evaporator 14b and the freezing gas-liquid separator 54b differs between the freezing and cooling operation (FIG. 6B) and the defrosting operation (FIG. 6C). The "refrigerant inlet" and "refrigerant outlet" here are based on the direction of refrigerant flow during the freezing and cooling operation. The freezing evaporator 14b is comprised of the inside of the refrigerant pipe 59 and fins 120, and cools the air inside the refrigerator by exchanging heat between the low-temperature refrigerant in the refrigerant pipe 59 and the air during the freezing and cooling operation. The fins 120 are heat dissipation members for increasing the efficiency of heat exchange from the refrigerant pipe 59 to the air. In order to improve heat transfer performance to the fins 120, the refrigerant pipes 59 are expanded to increase the diameter of the pipes and improve contact with the fins 120. Here, the freezing evaporator 14b cools two compartments, the freezer compartment 7 and the vegetable compartment 6, and furthermore, the freezer compartment 7, which is the cooling target, is in the freezing temperature range, so the cooling load is greater than that of the refrigeration evaporator 14a, which cools only the refrigerator compartment 2. Therefore, it is preferable that the surface area of ​​the fins 120 of the freezing evaporator 14b be larger than the surface area of ​​the fins included in the refrigeration evaporator 14a.

[0030] The refrigerant flowing through the refrigerant pipe 59 flows into the refrigeration gas-liquid separator 54b in a two-phase gas-liquid state. When the refrigerant flows into the refrigeration gas-liquid separator 54b, gravity causes the liquid refrigerant to remain in the lower part of the refrigeration gas-liquid separator 54b, and the gas refrigerant escapes through the refrigerant pipe 60 at the upper part, resulting in gas-liquid separation, preventing the liquid refrigerant from flowing into the compressor 24. The refrigerant pipe 59 inside the refrigeration gas-liquid separator 54b is inserted from the bottom of the refrigeration gas-liquid separator 54b. A hole 130 with a diameter of, for example, approximately 1.5 mm is provided to prevent refrigeration oil and the like from remaining in the refrigeration gas-liquid separator 54b. The hole 130 is connected to the refrigerant pipe 59.

[0031] 4B, the refrigeration evaporator 14b (refrigerant pipe 59 and fins 120), the refrigeration gas-liquid separator 54b, and the refrigerant pipe 60 of the first embodiment are all made of aluminum. The other refrigerant pipes described below are made of copper, and because aluminum and copper cannot be directly welded, pipe conversion parts 121 and 122, which are conversion parts that enable aluminum pipes to be connected to copper refrigerant pipes that form the other pipes, are used to enable connection to the copper refrigerant pipes that form the other pipes. Note that similar pipe conversion parts are also required when iron or the like is used instead of copper for the other refrigerant pipes.

[0032] <Configuration and Operation of Refrigeration Cycle (Refrigerant Flow Path) 200 in Refrigerator 1> The configuration and operation of the refrigeration cycle (refrigerant flow path) 200 in the refrigerator 1 will be described below with reference to Fig. 5 and Figs. 6A to 6C. Fig. 5 is a schematic diagram showing the configuration of the refrigeration cycle (refrigerant flow path) 200 in the refrigerator 1 of the first embodiment. Fig. 6A is an explanatory diagram showing the flow of the refrigerant in the refrigerator 1 during refrigeration cooling operation. Fig. 6B is an explanatory diagram showing the flow of the refrigerant in the refrigerator 1 during freezing cooling operation. Fig. 6C is an explanatory diagram showing the flow of the refrigerant in the refrigerator 1 during defrosting operation.

[0033] 5, the refrigerator 1 includes a compressor 24, a heat radiating section 50, a dryer 51, a three-way valve 52, a capillary tube 53, a refrigerating evaporator 14a, a freezing evaporator 14b, a refrigerating gas-liquid separator 54a, a freezing gas-liquid separator 54b, and a check valve 55. The refrigerator 1 also includes a three-way valve 101, a two-way valve 112, a defrosting capillary tube 103, and a check valve 104.

[0034] The compressor 24 is a component that compresses the refrigerant.

[0035] The heat dissipation unit 50 is a component that dissipates heat from the refrigerant. Here, the heat dissipation unit 50 will be described as having an external radiator 50a and wall surface heat dissipation piping 50b that dissipate heat from the refrigerant, and condensation prevention piping 50c that suppresses condensation on the front surfaces of the heat insulating partition walls 28, 29, and 30.

[0036] The dryer 51 is a component that removes moisture in the refrigeration cycle.

[0037] The three-way valve 52 is a refrigerant control unit that controls whether the refrigerant flows to the refrigeration evaporator 14a or the freezing evaporator 14b. Hereinafter, the "three-way valve 52" may be referred to as a "second refrigerant control unit." The three-way valve 52 has an outlet 52a connected to the refrigeration capillary tube 53a via a refrigerant pipe and an outlet 52b connected to the freezing capillary tube 53b via a refrigerant pipe, and can switch between the outlets 52a and 52b through which the refrigerant flows. Note that the three-way valve 52 in this embodiment can also be in a double-closed state that restricts refrigerant flow in both directions from the outlet 52a and the outlet 52b. The three-way valve 52 can also be in a double-open state that allows refrigerant to flow through both the outlet 52a and the outlet 52b.

[0038] The capillary tube 53 is a pressure reducing section that reduces the pressure of the refrigerant. The capillary tube 53 has a refrigerating capillary tube 53a that reduces the pressure of the refrigerant flowing to the refrigerating evaporator 14a side, and a freezing capillary tube 53b that reduces the pressure of the refrigerant flowing to the freezing evaporator 14b side. Hereinafter, the freezing capillary tube 53b may be referred to as a first pressure reducing section, and the refrigerating capillary tube 53a may be referred to as a second pressure reducing section.

[0039] The refrigeration evaporator 14a is a component that absorbs heat from the inside of the refrigeration compartment 2 by heat exchange between the refrigerant and the air inside the refrigeration compartment 2.

[0040] The freezing evaporator 14b is a component that exchanges heat between the refrigerant and the air in the freezing compartment 7, thereby absorbing heat from the inside of the freezing compartment 7 (and the vegetable compartment 6).

[0041] The refrigeration gas-liquid separator 54a is a component that separates the liquid refrigerant from the gas refrigerant and prevents the liquid refrigerant from flowing into the compressor 24, similar to the above-described freezing gas-liquid separator 54b.

[0042] Branching portion 110 is the portion where refrigerant flow path FP5 and refrigerant flow path FP8 join, and branching portion 111 is the portion where refrigerant flow path FP5 and refrigerant flow path FP7 branch off. Hereinafter, branching portion 111 may be referred to as a second branching portion, and branching portion 110 may be referred to as a third branching portion.

[0043] The check valve 55 and the two-way valve 112 are provided between the refrigeration gas-liquid separator 54b and the branching portion 56. In this embodiment, the check valve 55 and the two-way valve 112 are provided between the branching portion 111 and the branching portion 56. The branching portion 56 is the location where the refrigerant flow path FP4 and the refrigerant flow path FP5 join together.

[0044] The check valve 55 is a component that suppresses the backflow of refrigerant (flow from the branch 56 side to the branch 111 side) and suppresses the inflow of refrigerant into the freezing evaporator 14b during refrigeration / cooling operation. Although not shown, the check valve 55 is provided inside the foam insulation (insulated box 10) for space efficiency and to suppress the temperature effects on the freezing compartment 7 and the freezing evaporator chamber 8b. The two-way valve 112 is a refrigerant control unit that can suppress the refrigerant flow. During refrigeration / cooling operation, the two-way valve 112 is opened to allow the refrigerant to flow from the freezing evaporator 14b to the compressor 24 via the branch 56, and during defrosting operation, the two-way valve 112 is closed to suppress the refrigerant flow from the freezing evaporator 14b to the branch 56. Hereinafter, the "two-way valve 112" may be referred to as the "third refrigerant control unit."

[0045] The three-way valve 101 is a refrigerant control unit that switches the refrigerant flow direction between cooling operation (refrigeration cooling operation and freezing cooling operation) and defrosting operation. The three-way valve 101 directs the refrigerant to the heat radiating unit 50 during cooling operation (refrigeration cooling operation and freezing cooling operation), and directs the refrigerant to the freezing evaporator 14b, bypassing the heat radiating unit 50 during defrosting operation. Hereinafter, the "three-way valve 101" may be referred to as the "first refrigerant control unit." The three-way valve 101 includes an outlet 101a connected to the external radiator 50a via a refrigerant pipe and an outlet 101b connected to a refrigerant flow path FP7 that guides the refrigerant to the freezing evaporator 14b, and can switch the refrigerant outlet. Like the three-way valve 52, the three-way valve 101 can be in both a closed state and a closed state.

[0046] The defrosting capillary tube 103 is a pressure reducing section that reduces the pressure of the refrigerant that has flowed through the freezing evaporator 14b during defrosting operation so that the pressure is suitable for cooling in the refrigerating evaporator 14a. Hereinafter, the defrosting capillary tube 103 may be referred to as a third pressure reducing section.

[0047] The check valve 104 is a component similar to the check valve 55, and prevents refrigerant from flowing into the freezing evaporator 14b during refrigeration / cooling operation. The check valve 104 is provided between the freezing evaporator 14b and the junction 105. In this embodiment, the check valve 104 is provided between the defrosting capillary tube 103 and the junction 105. The junction 105 is a location where the refrigerant piping for refrigeration / cooling operation (refrigerant flow path FP4) and the refrigerant piping for defrosting operation (refrigerant flow path FP8) join (connect).

[0048] Refrigerator 1 has a refrigerant flow path FP so that a refrigerant flows between these components. In the example shown in Figures 6A to 6C, the refrigerant flow path will be described as being divided into refrigerant flow paths FP1 to FP8. However, the example shown in Figures 6A to 6C is merely an example, and the refrigerant flow paths may be divided (segmented) into a plurality of pipes or may be integrated into one refrigerant flow path, as long as it is not contrary to the context of this specification.

[0049] The refrigerant flow path FP1 is configured to connect the compressor 24 to the three-way valve 101.

[0050] The refrigerant flow path FP2 is configured to connect the outlet 101a of the three-way valve 101, through the external radiator 50a of the heat radiation section 50 and the wall surface heat radiation piping 50b, to the condensation prevention piping 50c.

[0051] The refrigerant flow path FP3 is configured to pass through the dryer 51 and connect the dew condensation prevention pipe 50c of the heat dissipation unit 50 to the three-way valve 52.

[0052] Refrigerant flow path FP4 is configured to connect outlet 52a of three-way valve 52 to branch portion 56. In the following description, the portion of refrigerant flow path FP4 that connects outlet 52a of three-way valve 52 to branch portion 105 will be referred to as "refrigerant flow path FP4a." Furthermore, the portion that connects branch portion 105 to branch portion 56 will be referred to as "refrigerant flow path FP4b."

[0053] Refrigerant flow path FP5 is configured to connect outlet 52b of three-way valve 52 to branching point 56, passing through refrigeration capillary tube 53b, refrigeration evaporator 14b, refrigeration gas-liquid separator 54b, two-way valve 112, and check valve 55. In the following description, the portion of refrigerant flow path FP5 that connects outlet 52b of three-way valve 52 to branching point 110 will be referred to as "refrigerant flow path FP5a." Also, the portion that connects branching point 110 to piping conversion unit 121, which is a piping conversion unit on the inlet side of refrigeration evaporator 14b, will be referred to as "refrigerant flow path FP5b," the portion that connects piping conversion unit 121 to piping conversion unit 122, which is a piping conversion unit on the outlet side of refrigeration evaporator 14b, will be referred to as "refrigerant flow path FP5c," and the portion that connects piping conversion unit 122 to branching point 111 will be referred to as "refrigerant flow path FP5d."

[0054] The refrigerant flow path FP6 is configured to connect the branching portion 56 to the suction port of the compressor 24. The refrigerator 1 has an internal heat exchanger 58. The internal heat exchanger 58 is a heat exchanger that allows some or all of the refrigerating capillary tube 53a, the freezing capillary tube 53b, and the defrosting capillary tube 103 to exchange heat with the refrigerant flow path FP6 (a part of the suction pipe 57).

[0055] The refrigerant flow path FP7 is a flow path that guides the high-temperature refrigerant discharged from the compressor 24 to the refrigeration evaporator 14b during defrosting operation, and is configured to connect the outlet 101b of the three-way valve 101 to the branch point 111.

[0056] The refrigerant flow path FP8 is a flow path that guides the refrigerant from the freezing evaporator 14b to the refrigerating evaporator 14a during defrosting operation, and is configured to connect the branching point 110 to the branching point 105 through the defrosting capillary tube 103 and the check valve 104. The order of the defrosting capillary tube 103 and the check valve 104 may be reversed.

[0057] In this embodiment, the refrigerant return pipes (pipes from the refrigeration evaporator 14a and the refrigeration evaporator 14b to the branching section 56 and the refrigerant flow path FP6) that return the refrigerant from the refrigeration evaporator 14a and the refrigeration evaporator 14b to the compressor 24 are referred to as "suction pipes 57."

[0058] The suction pipe 57 (refrigerant flow path FP6) can exchange heat with part or all of the refrigeration capillary tube 53a, part or all of the freezing capillary tube 53b, and / or part or all of the defrosting capillary tube 103 in the internal heat exchange section 58.

[0059] In the refrigerator 1 of the first embodiment, the refrigerating capillary tube 53a, the freezing capillary tube 53b, and the defrosting capillary tube 103 are soldered to the suction pipe 57. By soldering them and connecting them with metal members, the refrigerator 1 improves heat exchange efficiency. Note that the internal heat exchanger 58 only needs to be configured so that the refrigerating capillary tube 53a, the freezing capillary tube 53b, and the defrosting capillary tube 103 are close to the suction pipe 57 (refrigerant flow path FP6) and can exchange heat therebetween.

[0060] In this embodiment, the refrigerator 1 is described as using isobutane, which is a flammable refrigerant, as a refrigerant. The compressor 24 is described as including an inverter and capable of changing the rotation speed.

[0061] The flow resistance of the defrosting capillary tube 103 is set smaller than the flow resistances of the refrigeration capillary tube 53a and the refrigeration capillary tube 53b so that the flow resistance (magnitude of pressure loss under the same conditions) of the refrigerant flow path FP8 connecting the freezing evaporator 14b to the refrigeration evaporator 14a (≒ from the outlet of the freezing evaporator 14b to the refrigeration evaporator 14a. Hereinafter, the expression "from A to B" can be interpreted as including both ends of the range, A and B) in the defrosting operation is smaller than the flow resistance of the refrigerant flow path FP4a, which is the depressurization flow path in the refrigeration cooling operation, and the flow resistance of the refrigerant flow path FP5a, which is the depressurization flow path in the freezing cooling operation, for reasons that will be described later. The flow resistance of the refrigeration capillary tube 53a is smaller than the flow resistance of the refrigeration capillary tube 53b.

[0062] The flow of refrigerant during refrigerating cooling operation, freezing cooling operation, and defrosting operation will be described with reference to FIGS. 6A to 6C.

[0063] <Refrigerant flow during refrigeration cooling operation> 6A, in refrigeration cooling operation, three-way valve 101 opens outlet 101a on the heat radiating section 50 side and closes outlet 101b so that the refrigerant flows to heat radiating section 50 (external radiator 50a). Also, three-way valve 52 opens outlet 52a on the refrigeration capillary tube 53a side so that the refrigerant flows to refrigeration evaporator 14a via refrigeration capillary tube 53a. As a result, the refrigerant discharged from compressor 24 flows back to compressor 24 through refrigerant flow paths FP1, FP2, FP3, FP4, and FP6.

[0064] The components through which the refrigerant flows during refrigeration / cooling operation are described below. In refrigerator 1, when compressor 24 is driven, the refrigerant is compressed to become a high-temperature, high-pressure gas refrigerant. The high-temperature, high-pressure gas refrigerant passes through three-way valve 101, then flows through external radiator 50a, wall surface heat radiation piping 50b, and condensation prevention piping 50c, where it dissipates heat and becomes a liquid refrigerant. The refrigerant then flows through dryer 51 to remove moisture, and then reaches three-way valve 52. The refrigerant flowing out from outlet 52a is decompressed by refrigeration capillary tube 53a, becomes a low-temperature, low-pressure two-phase gas-liquid refrigerant, and then reaches refrigeration evaporator 14a through branching section 105. In refrigerator 1, air flows from refrigeration compartment 2 (FIG. 2) into refrigeration evaporator compartment 8a when refrigeration fan 9a is driven. The air that flows into the refrigeration evaporator chamber 8a exchanges heat with the low-temperature refrigerant in the refrigeration evaporator 14a as it passes through the refrigeration evaporator 14a, lowering its temperature and then being sent back to the refrigeration compartment 2 (Fig. 2). At this time, the refrigerant absorbs heat from the air in the refrigeration compartment 2 (Fig. 2), increasing its enthalpy and dryness, and becomes a nearly saturated gas refrigerant. The refrigerant then reaches the outlet of the refrigeration evaporator 14a, passes through the refrigeration gas-liquid separator 54a, and reaches the suction pipe 57. The suction pipe 57 forms a refrigerant flow path FP6 and is connected to the suction port of the compressor 24. The refrigerant flows through the suction pipe 57 (refrigerant flow path FP6) and returns to the compressor 24.

[0065] <Refrigerant flow during refrigeration / cooling operation> 6B, in the freezing and cooling operation, the three-way valve 101 opens the outlet 101a on the heat radiating unit 50 side and closes the outlet 101b so that the refrigerant flows to the heat radiating unit 50 (external radiator 50a). The three-way valve 52 also opens the outlet 52b on the freezing capillary tube 53b side so that the refrigerant flows to the freezing evaporator 14b via the freezing capillary tube 53b. As a result, the refrigerant discharged from the compressor 24 flows back to the compressor 24 through the refrigerant flow paths FP1, FP2, FP3, FP5, and FP6.

[0066] The components through which the refrigerant flows during freezing / cooling operation are described below. The flow of refrigerant from the compressor 24 to the three-way valve 52 and its effects on the refrigerant are similar to those during refrigeration / cooling operation. Because the three-way valve 52 allows the refrigerant to flow through the outlet 52b and closes the outlet 52a, the refrigerant flowing out of the outlet 52b is decompressed by the freezing capillary tube 53b, becoming a low-temperature, low-pressure, two-phase gas-liquid refrigerant. The refrigerant then travels through the branching section 110 and the piping conversion section 121 to the freezing evaporator 14b (refrigerant piping 59). Because the pressure reduction in the freezing capillary tube 53b is greater than that in the refrigeration capillary tube 53a, the refrigerant passing through the freezing evaporator 14b has a lower evaporation temperature than the refrigeration capillary tube 53a. In the refrigerator 1, air flows from the freezer compartment 7 (FIG. 2) and the vegetable compartment 6 (FIG. 2) into the freezing evaporator compartment 8b when the freezing fan 9b is driven. The air that flows into freezing evaporator chamber 8b exchanges heat with the low-temperature refrigerant in freezing evaporator 14b as it passes through freezing evaporator 14b, lowering its temperature and then being sent back to freezing compartment 7 and vegetable compartment 6. At this time, the refrigerant absorbs heat from the air inside the freezer (freezing compartment 7 and vegetable compartment 6), increasing its enthalpy and dryness, and becomes a nearly saturated gas refrigerant. The refrigerant then flows from the outlet of freezing evaporator 14b through freezing gas-liquid separator 54b, refrigerant piping 60, piping conversion unit 122, branching unit 111, open two-way valve 112, and check valve 55 to suction pipe 57. Suction pipe 57 has branching unit 56 where the downstream side of refrigeration gas-liquid separator 54a and the downstream side of freezing gas-liquid separator 54b join (connect), and branching unit 56 connects compressor 24. The refrigerant flows through the suction pipe 57 (refrigerant flow path FP6) and returns to the compressor 24. During freezing and cooling operation, the temperature of the refrigeration evaporator 14a is higher than the evaporation temperature (the temperature on the freezing evaporator 14b side). Therefore, the refrigerant in the refrigerant piping of the refrigeration evaporator 14a is in the gaseous range (all low-density gas refrigerant) and does not condense to form a liquid refrigerant in the refrigeration evaporator 14a. Therefore, even if a check valve or the like is not provided in the refrigerant flow path FP4b, the amount of refrigerant in the circulation flow path does not decrease. Furthermore, because the refrigerant flow path FP7 is located in a position where it can exchange heat with the outside air, its temperature becomes higher than the evaporation temperature (the temperature on the freezing evaporator 14b side) during freezing and cooling operation.Therefore, similar to the refrigerant flow path FP4b, even if a check valve or the like is not provided in the refrigerant flow path FP7, liquid refrigerant will not collect in the refrigerant flow path FP7, and the amount of refrigerant in the circulation path will not be affected.

[0067] 6A and 6B, the refrigerant returns to the compressor 24 via the suction pipe 57. At that time, the suction pipe 57 is configured to exchange heat with the refrigeration capillary tube 53a and the freezing capillary tube 53b in the internal heat exchanger 58. Therefore, the refrigerant passing through the suction pipe 57 is heated by the refrigeration capillary tube 53a in the refrigeration cooling operation, and is heated by the refrigerant in the freezing capillary tube 53b in the freezing cooling operation. In either case, the refrigerant returns to the compressor 24 with an increased enthalpy (higher temperature).

[0068] By providing such internal heat exchanger 58, refrigerator 1 can increase the temperature of the refrigerant drawn into compressor 24. Therefore, in refrigerator 1, the temperature of the refrigerant in suction pipe 57 (FIG. 3) can be increased in machine compartment 39 (FIG. 3) where outside air flows in and out, and condensation and frost formation on suction pipe 57 in machine compartment 39 can be prevented. Also, in refrigerator 1, suction pipe 57 can reduce the enthalpy of the refrigerant flowing into refrigeration evaporator 14a and freezing evaporator 14b by absorbing heat from refrigeration capillary tube 53a and freezing capillary tube 53. Therefore, refrigerator 1 can improve the cooling capacity of refrigeration evaporator 14a and freezing evaporator 14b. In addition, in refrigerator 1 using a refrigerant such as isobutane, by providing internal heat exchange member 58, the cooling capacity can be improved and the compression power (power consumption wa) of compressor 24 can be reduced, thereby improving cooling efficiency (the ratio of the amount of heat cooled to the input of compressor 24), i.e., energy saving performance.

[0069] In this embodiment, heat exchange occurs between the refrigerant pipe FP6 downstream of the branching point 56 and each of the capillary tubes 53a, 53b. However, the same effect can be obtained by heat exchange between the refrigerating capillary tube 53a and the refrigerant flow path from the refrigerating evaporator 14a to the branching point 56, and by heat exchange between the freezing capillary tube 56b and the refrigerant flow path from the freezing evaporator 14b to the branching point 56.

[0070] <Refrigerant flow during defrosting operation> 6C, in defrosting operation, the refrigerant discharged from compressor 24 flows through refrigerant flow paths FP1, FP7, FP5d, FP5c, FP5b, FP8, FP4b, and FP6, and returns to compressor 24. Note that refrigerant flow path FP4b is a refrigerant flow path in refrigerant flow path FP4 from branch point 105 to branch point 56, and FP5b, FP5c, and FP5d are refrigerant flow paths in refrigerant flow path FP5 from branch point 110 to branch point 111.

[0071] As shown in FIG. 6C , in defrosting operation, the three-way valve 101 opens outlet 101b on the refrigerant flow path FP7 side leading to the freezing evaporator 14b and closes outlet 101a. Even in defrosting operation, the compressor 24 is driven to compress the refrigerant into a high-temperature, high-pressure gas refrigerant. After passing through the three-way valve 101, the gas refrigerant flows through the branching section 111, the piping conversion section 122, and the freezing gas-liquid separator 54b to the freezing evaporator 14b, where it exchanges heat with the freezing evaporator 14b. This causes the high-temperature, high-pressure refrigerant in the freezing evaporator 14b to radiate heat, heating the freezing evaporator 14b. This heat radiation lowers the temperature of the gas refrigerant and liquefies it. The liquefied refrigerant flows into the refrigerant flow path FP8 via the piping conversion section 121 and the branching section 110 and passes through the defrosting capillary tube 103. At this time, the refrigerant is decompressed by the defrosting capillary tube 103 to become a low-temperature, low-pressure, two-phase gas-liquid refrigerant. During defrosting operation, the outlet 52a of the three-way valve 52 is closed, so the flow resistance of the refrigerant flow path FP4a is greater than the flow resistance of the refrigerant flow path FP4b. Therefore, the low-temperature, low-pressure refrigerant passes through the check valve 104 and then reaches the inlet of the refrigeration evaporator 14a via the branching part 105. Note that FP5a and FP4a may each be provided with a check valve that allows the refrigerant to pass only in the refrigeration / cooling operation and the refrigeration / cooling operation, respectively. The low-temperature refrigeration evaporator 14a exchanges heat with the ambient air. This lowers the temperature of the ambient air. The low-temperature ambient air is sent to the refrigeration compartment 2 (FIG. 2) by the refrigeration fan 9a. This allows the refrigerator 1 to cool the refrigeration compartment 2. Through this heat exchange, the refrigerant in the refrigeration evaporator 14a absorbs heat from the air in the refrigeration compartment 2, increasing its enthalpy and dryness, and becoming a nearly saturated gas refrigerant. The refrigerant then reaches the outlet of the refrigeration evaporator 14a, passes through the refrigeration gas-liquid separator 54a, and reaches the suction pipe 57. The refrigerant then flows through the suction pipe 57 and returns to the compressor 24.

[0072] The flow of the refrigerant from the branching part 105 to the compressor 24 during the defrosting operation is the same as that during the refrigerating / cooling operation (FIG. 6A). However, during the defrosting operation, the refrigerant in the suction pipe 57 exchanges heat mainly with the refrigerant in the defrosting capillary tube 103 via the internal heat exchanger 58.

[0073] FIG. 7 is a Ph diagram showing the state of the refrigeration cycle during the defrosting operation shown in FIG. 6C. In FIG. 7, the vertical axis represents pressure P, and the horizontal axis represents specific enthalpy h. Note that FIG. 7 shows a theoretical cycle in which various losses are ignored. The difference Δq between the two enthalpies shown in FIG. 7 is the same value. The heat quantity q and power consumption wa shown in FIG. 7 are the energy of the refrigerant per 1 kg.

[0074] State C1 shows the state of the inlet of the compressor 24. State C2 shows the state of the outlet of the compressor 24. State C3 shows the state of the refrigerant in the refrigerant flow path from the outlet of the freezing evaporator 14b (refrigerant flow paths FP5b, FP5c) to the inlet of the defrosting capillary tube 103. State C4 shows the state of the refrigerant at the outlet of the defrosting capillary tube 103. State C5 shows the state of the outlet of the refrigeration evaporator 14a (refrigerant flow path FP6 side).

[0075] The refrigerant in state C1 is compressed by the compressor 24 and reaches state C2 with condensation pressure Pd. The power consumption of the compressor 24 at this time is wa. The refrigerant in state C2 releases heat by a heat release amount qH through heat exchange with the freezing evaporator 14b, and reaches state C3. As the refrigerant in state C3 passes through the defrosting capillary tube 103, the pressure of the refrigerant decreases from condensation pressure Pd to evaporation pressure Ps. Furthermore, the refrigerant in state C3 reaches state C4 through heat exchange by the internal heat exchanger 58, whereby the specific enthalpy decreases by Δq, the difference between q3 in state C3 and q4 in state C4. The refrigerant in state C4 then absorbs heat by a heat absorption amount qc through heat exchange with the refrigeration evaporator 14a, and reaches state C5. The refrigerant in state C5 returns to the compressor 24 through the suction pipe 57. At this time, the specific enthalpy of the refrigerant in state C5 increases by the difference Δq between q1 in state C1 and q5 in state C5 due to heat exchange by the internal heat exchanger 58, and the refrigerant reaches state C1. That is, the refrigerant in state C5 returns to the state at the inlet of the compressor 24 by passing through the suction pipe 57.

[0076] Here, the two enthalpy differences Δq shown in FIG. 7 have the same value. Therefore, the specific enthalpy difference (q1-q3) between state C1 and state C3 has the same value as the heat absorption amount qc. Also, as can be seen from FIG. 7, the heat radiation amount qH is "qH=(wa+(q1-q3))=(wa+qc)". Therefore, in the theoretical cycle, the heat radiation amount qH used to heat the freezing evaporator 14b is the sum of the power consumption wa of the compressor 24 and the heat absorption amount qc of the refrigeration evaporator 14a (wa+qc). Therefore, the refrigerator 1 can obtain the heat radiation amount qH (heat amount) that is greater than the power consumption wa of the compressor 24 by the heat absorption amount qc from the refrigeration evaporator 14a, and can effectively heat the freezing evaporator 14b.

[0077] The above are the basic specifications of the refrigerator 1 of the first embodiment.

[0078] <Effect of defrosting method of refrigerator 1> The effect of the defrosting mode of the refrigerator 1 realized by the refrigeration cycle 200 shown in Fig. 6C will be described below. The defrosting mode of the refrigerator 1 has higher energy-saving performance than the defrosting mode using an electric heater for the following reasons.

[0079] In a defrosting mode using a general electric heater, the heat generation amount of the heater used to heat the evaporator is equal to the power consumption. In contrast, in the defrosting mode of the refrigerator 1, as shown in FIG. 7, the refrigerator 1 can obtain a heat radiation amount qH (heating amount) used to heat the freezing evaporator 14b that is greater than the power consumption wa of the compressor 24. In addition, in a defrosting mode using an electric heater that heats the freezing evaporator 14b via radiation or air convection, such as a radiant heater, much of the heat generation amount is used to heat the surrounding wall surfaces. As a result, the amount of heat generated by the freezing evaporator 14b is less than the heat generation amount. In contrast, in the defrosting mode of the refrigerator 1, direct heat exchange occurs between the refrigerant in the refrigerant pipe 59, which is the heat source, and the freezing evaporator 14b. As a result, the refrigerator 1 can reduce heat loss. This defrosting mode of the refrigerator 1 provides a defrosting operation with higher heating efficiency than a defrosting mode using an electric heater.

[0080] Furthermore, in the defrosting mode of refrigerator 1, heat absorption amount qc is absorbed from refrigerating compartment 2 via refrigerating evaporator 14a during defrosting operation. Therefore, the defrosting mode of refrigerator 1 can reduce the thermal load on refrigerating compartment 2 by performing the defrosting operation of Fig. 6C, and can reduce the amount of heat absorption required in refrigerating cooling operation of Fig. 6A. In other words, the amount of power consumed by compressor 24 in refrigerating cooling operation can be reduced.

[0081] For these reasons, the defrosting mode of the refrigerator 1, in which the cooling of the refrigerator compartment 2 is utilized as heat absorption and the freezing evaporator 14b is heated with a high-temperature refrigerant, is a defrosting mode with high energy-saving performance.

[0082] Hereinafter, a description will be given of the effects achieved by the refrigeration cycle specifications of the refrigerator 1 of Example 1. First, the configuration of a refrigeration cycle 1002 of a comparative example will be described with reference to FIG.

[0083] 8 is a schematic diagram showing the configuration of a refrigeration cycle (refrigerant flow path) in a comparative example. A refrigeration cycle 1002 in the comparative example is a refrigeration cycle that is virtually designed with reference to the refrigeration cycle of Patent Document 1.

[0084] Compared with the refrigeration cycle 100 (FIG. 5) of the first embodiment, the refrigeration cycle 1002 of the comparative example includes a refrigeration evaporator 14b2 instead of the refrigeration evaporator 14b, which includes a refrigerant pipe 102 that is a refrigerant pipe that exchanges heat with the refrigeration evaporator during defrosting operation, in addition to a refrigerant pipe 59 that exchanges heat with the refrigeration evaporator during freezing and cooling operation. Also, the refrigeration cycle 1002 differs in that a check valve 204 and refrigerant flow paths FP21 to FP28 are provided instead of the defrosting capillary tube 103, check valve 104, and refrigerant flow paths FP1 to FP8.

[0085] The refrigerant flow path FP21 is configured to connect the compressor 24 to the three-way valve 101.

[0086] The refrigerant flow path FP22 is configured to connect the three-way valve 101 to the condensation prevention pipe 50c of the heat radiating section 50, passing through the external radiator 50a of the heat radiating section 50 and the wall surface heat radiating pipe 50b.

[0087] The refrigerant flow path FP23 is configured to pass through the dryer 51 and connect the dew condensation prevention pipe 50c of the heat dissipation unit 50 to the three-way valve 52.

[0088] The refrigerant flow path FP24 is configured to connect the three-way valve 52 to the branching portion 56, passing through the refrigeration capillary tube 53a, the refrigeration evaporator 14a, and the refrigeration gas-liquid separator 54a.

[0089] The refrigerant flow path FP25 is configured to connect the three-way valve 52 to the branching portion 56 through the refrigeration capillary tube 53b, the refrigeration evaporator 14b2, the refrigeration gas-liquid separator 54b, and the check valve 55.

[0090] The refrigerant flow path FP26 is configured to connect the branching portion 56 to the compressor 24.

[0091] The refrigerant flow path FP27 is configured to connect the three-way valve 101 to the defrosting pipe 102.

[0092] The refrigerant flow path FP28 is configured to connect the defrosting pipe 102 through the check valve 204 to the branching point 106. The branching point 106 is a location where the refrigerant piping for cooling operation (refrigerant flow path FP22) and the refrigerant piping for defrosting operation (refrigerant flow path FP28) join (connect).

[0093] In the refrigeration cycle 1002 of the comparative example, during defrosting operation, the refrigerant does not flow through the refrigerant pipe 59 that exchanges heat with the freezing evaporator 14b2 during cooling operation, but during defrosting operation, the refrigerant flows through the defrosting pipe 102 that exchanges heat with the freezing evaporator 14b2, and the refrigerant that has passed through the defrosting pipe 102 flows upstream of the dryer 51 and the three-way valve 52. That is, in the refrigeration cycle 1002 of the comparative example, the refrigerant pipe that exchanges heat with the freezing evaporator 14b2 differs between cooling operation and defrosting operation, and during defrosting operation, the refrigerant is passed through the refrigeration capillary tube 53a and then flows into the refrigeration evaporator 14a.

[0094] The other parts of the refrigeration cycle 1002 of the comparative example are the same as those of the refrigeration cycle 200 of the first embodiment (FIG. 5).

[0095] The effects unique to the refrigerator 1 of the first embodiment will be described below in comparison with a comparative example. <The benefits of using common refrigerant piping for refrigeration / cooling operation and defrosting operation, and the configuration required for this> In the refrigeration cycle 1002 of the comparative example, the refrigerant pipes that exchange heat with the freezing evaporator 14b2 are different between the cooling operation and the defrosting operation. Therefore, the freezing evaporator 14b2 requires a special evaporator that is different from evaporators that use a general electric heater for defrosting. Furthermore, the increased number of refrigerant pipes tends to increase the cost of the evaporators. Furthermore, an increased number of refrigerant pipes imposes restrictions on the arrangement of the refrigerant pipes 59 or the defrosting pipe 102, resulting in a decrease in the heat exchange efficiency between the refrigerant pipes and the fins of the freezing evaporator 14b during the cooling operation or the defrosting operation, or an increase in the fin dimensions.

[0096] In contrast, in the refrigeration cycle 200 of this embodiment, the same refrigerant piping 59 is used during defrosting operation as during freezing and cooling operation, so that an evaporator that uses a general electric heater for defrosting can be used as the freezing evaporator 14b. In addition, there are fewer design restrictions, and it is easy to improve the efficiency of heat exchange from the refrigerant piping 59 to the fins 120 (see FIG. 4A) during freezing and cooling operation and defrosting operation.

[0097] Frost also forms on the refrigerant pipe 59 itself. In the comparative example, defrosting is performed by heating the refrigerant pipe 59 from the defrosting pipe 102 through heat conduction of the fins or refrigerant pipe or through air (convection), but in this embodiment, a high-temperature refrigerant flows directly into the refrigerant pipe 59, so frost on the refrigerant pipe 59 can be melted highly efficiently. Frost may form on the refrigeration gas-liquid separator 54b, but whereas in the comparative example, the refrigeration gas-liquid separator 54b cannot be directly heated, in the refrigeration cycle 200 of this embodiment, a high-temperature refrigerant also flows into the refrigeration gas-liquid separator 54b. Therefore, frost formed on the refrigeration gas-liquid separator 54b can also be melted highly efficiently.

[0098] <Two-way valve (third refrigerant control section) 112 and its effects> Here, we will explain the ingenuity of this embodiment in providing a highly energy-saving defrosting operation that heats the freezing evaporator 14b with a high-temperature refrigerant while utilizing the cooling of the refrigerator compartment 2 as heat absorption, and in exchanging heat with the freezing evaporator 14b using the same refrigerant flow path during both the freezing / cooling operation and the defrosting operation.

[0099] One is that a two-way valve 112 is provided between the branching portion (second branching portion) 111 and the branching portion (first branching portion) 56. In order to perform a defrosting operation in which the freezing evaporator 14b is heated with a high-temperature refrigerant while utilizing the cooling of the refrigerator compartment 2 as heat absorption, it is necessary that the refrigerant discharged from the compressor 24 flows to the refrigeration evaporator 14a via the freezing evaporator 14b during the defrosting operation. On the other hand, in the freezing / cooling operation, the outlet of the freezing evaporator 14b is connected to the compressor 24 by a suction pipe 57 via the freezing gas-liquid separator 54b, the freezing evaporator downstream piping 60, the refrigerant flow path FP5d, and the branching portion 111 so that the refrigerant flows from the freezing evaporator 14b to the compressor 24. Basically, if the refrigerant is decompressed after passing through the freezing evaporator 14b, this will result in a decrease in the efficiency of the refrigeration cycle, and therefore the flow path resistance in the refrigerant flow path from the freezing evaporator 14b to the compressor 24 is minimized. Therefore, if this flow path is not closed by the two-way valve 112 during the defrosting operation, the refrigerant will return to the compressor 24 without flowing to the refrigerating evaporator 14a, and the defrosting operation will not be possible.

[0100] Specifically, in refrigerator 1 of Example 1, the refrigerant discharged from compressor 24 flows through three-way valve 101, branching portion 111, and suction pipe 57, and returns directly to compressor 24. In this case, almost no refrigerant flows not only to refrigerating evaporator 14a but also to freezing evaporator 14b, and therefore the defrosting operation itself is not established.

[0101] In the case of Example 2 described later in FIG. 10, even if the two-way valve 112 is not present (or does not function), high-temperature refrigerant from the compressor 24 flows into the freezing evaporator 14b, and the freezing evaporator 14b can be heated. However, since no refrigerant flows into the refrigeration evaporator 14a, the cooling and heat absorption effect of the refrigeration evaporator 14a for the refrigerator compartment 2 cannot be obtained, and energy-saving performance is reduced.

[0102] Therefore, in this embodiment, a two-way valve 112 is provided that closes a part of the flow path from the freezing evaporator 14b to the compressor 24 during cooling operation, and the two-way valve 112 is closed during defrosting operation so that the refrigerant flows through the compressor 24, the freezing evaporator 14b, and the refrigerating evaporator 14a in this order and returns to the compressor 24.

[0103] That is, the two-way valve 112 is provided between the freezing evaporator 14b and the compressor 24, and during defrosting operation, the freezing evaporator 14b bypasses the refrigerating evaporator 14a and does not return to the compressor 24. This realizes a configuration in which the same refrigerant piping is used to exchange heat with the freezing evaporator 14b during defrosting operation and freezing / cooling operation in the refrigerator 1 equipped with a defrosting operation that heats the freezing evaporator 14b with a high-temperature refrigerant while utilizing the cooling of the refrigerator compartment 2 as heat absorption.

[0104] Based on the above description, the refrigerator 1 of this embodiment is configured as follows. Refrigerator compartment 2 and a refrigeration evaporator 14a for cooling the refrigeration compartment 2; Freezer compartment 7 and a freezing evaporator 14b for cooling the freezing compartment 7; a compressor 24 for compressing a refrigerant; a heat dissipation unit (50) that dissipates heat from the refrigerant; a first pressure reducing section 53b and a second pressure reducing section 53a for reducing the pressure of the refrigerant; a first branch portion 56 provided in the refrigerant flow path; a first refrigerant control unit (101), a second refrigerant control unit (52), and a third refrigerant control unit (112) that perform at least one of switching and closing of the refrigerant flow path; In the freezing and cooling operation for cooling the freezing compartment 7, the refrigerant discharged from the compressor 24 flows through the first refrigerant control unit 101, the heat dissipation unit 50, the second refrigerant control unit 52, the first pressure reducing unit 53b, the freezing evaporator 14b, the third refrigerant control unit 112, and the first branching unit 56 in this order, and returns to the compressor 24, where it cools the freezing evaporator 14b. The refrigerant flow paths FP1 to FP3, FP5, and FP6 are configured so that In the defrosting operation for melting the frost on the freezing evaporator 14b, the third refrigerant control unit 112 closes the refrigerant flow path that bypasses the refrigerating evaporator 14a from the freezing evaporator 14b and returns to the compressor 24, and the refrigerant discharged from the compressor 24 flows through the first refrigerant control unit 101, the freezing evaporator 14b, and the refrigerating evaporator 14a in this order, returns to the compressor 24, and heats the freezing evaporator 14b. The refrigerant flow paths FP7, FP5d to FP5b, FP8, FP4b, and FP6 are configured so that The refrigerant flow path that exchanges heat with the freezing evaporator 14b in the defrosting operation and the refrigerant flow path that exchanges heat with the freezing evaporator 14b in the freezing / cooling operation are configured by the same refrigerant pipes FP5b, FP5c, and FP5d.

[0105] <Position of the two-way valve 112 in the first embodiment> Here, the two-way valve 112 in the first embodiment is preferably provided at a location that does not restrict the refrigerant flow from the compressor 24 to the freezing evaporator 14b during defrosting operation, and does not restrict the refrigerant flow from the refrigeration evaporator 14a to the compressor 24. To achieve this in the first embodiment, a refrigerant flow path control unit such as the two-way valve 112 or a three-way valve described later is preferably provided in the refrigerant flow path between the branching portion 111 and the branching portion 56, including the branching portion 111 and the branching portion 56 themselves, in the flow path from the freezing evaporator 14b to the compressor 24.

[0106] <Modification of Example 1> The branching portion 111 or the branching portion 56 itself may be provided with a function as a refrigerant flow control portion, instead of the two-way valve 112. Modifications 1 and 2 of the refrigeration cycle (refrigerant flow path) 200 of the first embodiment will be described with reference to Figures 9A and 9B.

[0107] A refrigeration cycle 201 which is a first modification of the first embodiment will be described with reference to Fig. 9A. Fig. 9A is a schematic diagram showing a first modification of the refrigeration cycle (refrigerant flow path) 200 of the first embodiment. Refrigeration cycle 201 is an example in which branch point 111 in the range from branch point 111 to branch point 56 is provided with a three-way valve 211, and no two-way valve 112 is provided. The three-way valve 211 preferably connects refrigerant flow path FP5d to suction pipe 57 during freezing / cooling operation, and connects refrigerant flow path FP5d to refrigerant flow path FP7 while blocking the flow path to suction pipe 57 during defrosting operation.

[0108] A refrigeration cycle 202 which is a second modification of the first embodiment will be described with reference to Fig. 9B. Fig. 9B is a schematic diagram showing the second modification of the refrigeration cycle (refrigerant flow path) 200 of the first embodiment. Refrigeration cycle 202 is an example in which branch portion 56 in the range from branch portion 111 to first branch portion 56 is provided as a three-way valve 256, and two-way valve 112 is not provided. Three-way valve 256 connects refrigerant flow paths FP5 and FP6 during freezing / cooling operation. At this time, it is preferable that three-way valve 256 closes the flow path to refrigerant flow path FP4b, and three-way valve 52 closes the flow path to refrigerant flow path FP4a. Furthermore, it is preferable that three-way valve 256 closes refrigerant flow path FP5d during defrosting operation, while connecting refrigerant flow paths FP4 and FP6.

[0109] 5 and the like is a refrigerant control unit that can also suppress the refrigerant flow from the branch portion 56 to the freezing evaporator 14b side, the check valve 55 may be eliminated and the two-way valve 112 may be closed during both the defrosting operation and the refrigeration / cooling operation. On the other hand, a typical two-way valve is specialized in suppressing the refrigerant flow in one direction, and a two-way valve that can suppress the refrigerant flow from the freezing evaporator 14b to the branch portion 56 side cannot sufficiently suppress the refrigerant flow from the branch portion 56 side to the freezing evaporator 14b side. Therefore, both the check valve 55 and the two-way valve 112 are provided in the first embodiment.

[0110] Similarly, if three-way valve 211 in Fig. 9A is a refrigerant control unit that can also suppress refrigerant flow from branching portion 56 to freezing evaporator 14b, check valve 55 may be eliminated and three-way valve 211 may be closed during refrigeration cooling operation. If three-way valve 256 in Fig. 9B is a refrigerant control unit that can also suppress refrigerant flow from three-way valve 256 to freezing evaporator 14b, check valve 55 may be eliminated and the flow path of three-way valve 256 on the freezing evaporator 14b side may be closed during refrigeration cooling operation.

[0111] Furthermore, in the first embodiment, the check valve 55 is provided between the two-way valve 112 and the branch portion 56, but it may be provided between the branch portion 111 and the branch portion 56.

[0112] Based on the above description, the refrigerator 1 of this embodiment is configured as follows. A refrigeration gas-liquid separator 54b is provided to separate the refrigerant that has passed through the refrigeration evaporator 14a into gas and liquid. The refrigeration gas-liquid separator 54b is provided in the refrigerant flow paths FP5c and FP5d from the refrigeration evaporator 14b to the third refrigerant control unit 112 during the refrigeration / cooling operation. the refrigerant flow path for the defrosting operation has a second branch portion 111 that merges with the refrigerant flow path FP5d for the freezing / cooling operation between the first refrigerant control portion 101 and the freezing evaporator 14b, and a third branch portion 110 that branches off from the refrigerant flow path FP5b for the freezing / cooling operation between the freezing evaporator 14b and the first pressure reducing portion 53b; The second branch portion 111 is provided between the refrigeration gas-liquid separator 54b and the first branch portion 56, The third refrigerant control section 112 is provided in the range from the second branch section 111 to the first branch section 56 .

[0113] <Effects of Capillary Tube 103> In Comparative Example 1, the same refrigerating capillary tube 53a as that used in the refrigerating / cooling operation is used during the defrosting operation, but the refrigerator 1 of this embodiment is provided with a defrosting capillary tube 103 as an independent capillary tube. The reason for this will be explained below.

[0114] In the refrigeration cycles 1002 of the present embodiment and the comparative example, during defrosting operation, the refrigerant exchanges heat with the frosted refrigeration evaporators 14b, 14b2, which are significantly cooler than the outside of the refrigerator. Therefore, the condensation temperature of the refrigerant is likely to be lower during defrosting operation than during cooling operation, in which heat is radiated to the outside of the refrigerator by the heat radiator 50. That is, the condensation pressure Pd is likely to be lower. In the refrigeration cycle 1002 of the comparative example (FIG. 8), during defrosting operation, the refrigerant condensation pressure Pd is reduced from a low state in the refrigerant flow path FP24a, including the refrigeration capillary tube 53a, as in refrigeration / cooling operation. Therefore, in the refrigeration cycle 1002 of the comparative example, the refrigerant evaporation pressure Ps during defrosting operation is likely to be excessively low. Generally, when the evaporation pressure Ps decreases and the difference between the evaporation pressure Ps and the condensation pressure Pd increases, the amount of heat released per kg of refrigerant qH (Figure 7) does not change significantly, but the power consumption wa (Figure 7) of the compressor 24 increases, resulting in a decrease in energy-saving performance. Also, when the evaporation pressure Ps is low, the refrigerant density decreases, and the amount of refrigerant discharged from the compressor 24 at the same rotation speed (mass flow rate) decreases, which tends to reduce the amount of heat released per unit time QH [W] (= amount of heat released per kg of refrigerant qH [J / kg] × amount of refrigerant [kg / s]), and the defrosting time tends to increase.

[0115] In contrast, in the refrigeration cycle 200 of this embodiment (FIG. 5), like the refrigeration cycle 1002 of the comparative example, the refrigerant condensation pressure Pd during defrosting operation tends to be lower than during cooling operation. However, the defrosting capillary tube 103, which has lower flow resistance than the refrigeration capillary tube 53a, is used to reduce the pressure. Therefore, in the refrigeration cycle 200 of this embodiment, the refrigerant evaporation pressure Ps during defrosting operation is higher than the refrigeration pressure during defrosting operation of the refrigeration cycle 1002 of the comparative example (FIG. 8). Therefore, the pressure difference between the condensation pressure Pd and the evaporation pressure Ps is small, which results in higher energy-saving performance than the comparative example, and also makes it easier to increase the heat radiation amount QH and shorten the defrosting time. Because refrigeration cooling by the freezing evaporator 14b is not possible during the defrosting time, shortening the defrosting time reduces the time during which refrigeration cooling by the freezing evaporator 14b is not possible, thereby suppressing temperature fluctuations in the storage compartment.

[0116] That is, the capillary tube 103 for the defrosting operation is provided independently, and the flow path resistance of the refrigerant flow path FP8 connecting the freezing evaporator 14b to the refrigerating evaporator 14a during the defrosting operation is made smaller than the flow path resistance of the refrigerant flow path FP4a, which is the pressure reduction flow path during the refrigerating cooling operation, thereby enabling defrosting to be performed in a short defrosting time and with even higher heating efficiency during the defrosting operation.

[0117] It should be noted that increasing the rotational speed of the compressor 24 can be considered as a way to increase the heat dissipation amount QH [W], but it is desirable to keep the rotational speed as low as possible because this may result in limitations on the use of the compressor 24, increased noise due to increased rotational speed, and reduced energy-saving performance.

[0118] In the refrigeration cycle 200 (FIG. 5) of this embodiment, a defrosting capillary tube 103 (thin tube) is used to generate a pressure difference between the heat release side and the heat absorption side. However, frost can be melted as long as the temperature on the heat release side exceeds the frost melting temperature (0°C), and heat absorption from the refrigerator compartment 2 can be achieved as long as the temperature on the evaporation side is lower than that of the refrigerator compartment 2 (approximately 4°C on average, or approximately 10°C at high temperatures). Therefore, a large pressure difference is not necessary. Therefore, as long as the condensation temperature can be sufficiently lowered, the refrigeration cycle 200 (FIG. 5) of this embodiment may be configured without using a defrosting capillary tube 103 such as a thin tube, with almost no pressure difference between the heat release side and the heat absorption side, with only the pressure loss occurring in the refrigerant piping.

[0119] Based on the above description, the refrigerator 1 of this embodiment is configured as follows. In the refrigeration cooling operation for cooling the refrigerator compartment 2, the refrigerant discharged from the compressor 24 flows through the first refrigerant control unit 101, the heat radiating unit 50, the second refrigerant control unit 52, the second pressure reducing unit 53a, the refrigeration evaporator 14a, and the first branching unit 56 in this order, and returns to the compressor 24, where it cools the refrigeration evaporator 14a. The refrigerant flow paths FP1 to FP4 and FP6 are configured so that the refrigerant discharged from the compressor 24 flows through the first refrigerant control unit 101, the heat radiating unit 50, the second refrigerant control unit 52, the second pressure reducing unit 53a, the refrigeration evaporator 14a, and the first branching unit 56, and returns to the compressor 24, where it cool The flow resistance of the refrigerant flow paths FP5c, FP5b, and FP8 connecting the outlet of the freezing evaporator 14b to the refrigeration evaporator 14a during defrosting operation is set to be smaller than the flow resistance of the refrigerant flow paths FP3 and FP4a connecting the outlet of the heat dissipation section 50 to the refrigeration evaporator 14a during refrigeration cooling operation.

[0120] The refrigerator 1 also includes a third decompression unit 103 that decompresses the refrigerant. the refrigerant flow path for the defrosting operation has a second branch portion 111 that merges with the refrigerant flow path FP5d for the freezing and cooling operation between the first refrigerant control portion 101 and the freezing evaporator 14b in the refrigerant flow for the defrosting operation, and a third branch portion 110 that branches from the refrigerant flow path FP5b for the freezing and cooling operation between the freezing evaporator 14b and the first pressure reducing portion 53b; The third pressure reducing section 103 is provided in a refrigerant flow path FP8 that connects the third branching section 110 and the refrigeration evaporator 14a in the defrosting operation.

[0121] <Effects specific to the first embodiment (relationship with the refrigeration gas-liquid separator 54b)> As another innovation, in refrigerator 1 of this embodiment, branch portion 111 is provided in the refrigerant flow path connecting freezing gas-liquid separator 54b and branch portion 56. As described in FIG. 4A, freezing evaporator 14b of refrigerator 1 is made of aluminum up to freezing gas-liquid separator 54b, and the other refrigerant piping is made of copper. Therefore, piping conversion portions 121 and 122 are provided before and after freezing evaporator 14b and freezing gas-liquid separator 54b to connect the aluminum refrigerant piping with the copper refrigerant piping.

[0122] Here, even if branching portion 111 is provided between refrigeration gas-liquid separator 54b and refrigeration evaporator 14b, it is possible to perform defrosting operation by heating refrigeration evaporator 14b by flowing high-temperature refrigerant through it. However, in this case, in order to connect to refrigerant flow path FP7, the refrigerant piping between refrigeration gas-liquid separator 54b and refrigeration evaporator 14b must be made of copper, or part or all of refrigerant flow path FP7 must be made of aluminum. This requires measures such as providing an additional piping conversion section to connect aluminum and copper, or making refrigeration gas-liquid separator 54b out of copper, which may increase manufacturing difficulty and costs.

[0123] On the other hand, as in this embodiment, by providing branching section 111, which is a refrigerant flow path branching section for defrosting operation and refrigeration / cooling operation, between refrigeration gas-liquid separator 54b and branching section 56, the piping conversion section for connecting aluminum and copper and refrigeration gas-liquid separator 54b may be the same as the evaporator used for defrosting using a general electric heater shown in Fig. 4A. In addition, since the high-temperature refrigerant from compressor 24 also flows into refrigeration gas-liquid separator 54b, even if frost forms on refrigeration gas-liquid separator 54b, the high-temperature refrigerant can melt it efficiently as described above.

[0124] <Effect of the holes 130 in the refrigeration gas-liquid separator 54b> In the refrigerant flow during the defrosting operation, the holes 130 in the refrigeration gas-liquid separator 54b shown in Fig. 4B work effectively. As shown in Fig. 6C, in the defrosting operation of this embodiment, the refrigerant flows through the refrigeration evaporator 14b and the refrigeration gas-liquid separator 54b in the opposite direction to that during the refrigeration / cooling operation shown in Fig. 6B.

[0125] 4A and 4B, the refrigerant pipe 60 downstream of the refrigeration evaporator 14b is disposed on the upper side of the refrigeration gas-liquid separator 54b, and the refrigerant pipe 59 that returns the refrigerant to the compressor 24 is disposed on the lower side. The tip of the refrigerant pipe 59 is generally provided at a position higher than the lower end of the interior of the refrigeration gas-liquid separator 54b, i.e., above the lower end of the interior of the refrigeration gas-liquid separator 54b.

[0126] During defrosting operation, the refrigerant gas-liquid separator 54b is basically filled with high-temperature gas refrigerant discharged from the compressor 24. Therefore, it is not a problem if the end of the refrigerant pipe 59 is located higher than the lower end of the refrigerant pipe 59. However, it is possible that the gas refrigerant condenses in the refrigerant flow path leading to the refrigerant gas-liquid separator 54b or in the refrigerant gas-liquid separator 54b, causing liquid refrigerant to accumulate in the refrigerant gas-liquid separator 54b below the end of the refrigerant pipe 59. If too much refrigerant accumulates in the refrigerant gas-liquid separator 54b, the refrigerant cannot circulate properly. In contrast, in this embodiment, the hole 130 is provided at the bottom of the refrigerant pipe 59 in the refrigerant gas-liquid separator 54b. This allows liquid refrigerant accumulating in the bottom of the refrigerant gas-liquid separator 54b to flow toward the refrigeration evaporator 14b. In other words, the hole 130 prevents refrigerant shortages in the refrigerant gas-liquid separator 54b during defrosting operation.

[0127] Based on the above description, the refrigerator 1 of this embodiment is configured as follows. The refrigerant pipe 59 on the side of the refrigeration evaporator 14b, which is provided inside the refrigeration gas-liquid separator 54b, has its tip located above the lower end of the interior of the refrigeration gas-liquid separator 54b and has a hole 130 that allows the refrigerant to flow from the refrigeration gas-liquid separator 54b to the refrigeration evaporator 14b side.

[0128] <Effects of the internal heat exchange section 58> In the refrigerator 1 of the first embodiment, the defrosting capillary tube 103 also exchanges heat with the suction pipe 57. That is, the refrigeration cycle 200 of the refrigerator 1 has an internal heat exchanger 58. This allows the refrigerator 1 to increase the temperature of the refrigerant sucked into the compressor 24, and prevents condensation and frost from forming on the suction pipe 57 (FIG. 5) in the machine room 39 (FIG. 3).

[0129] 7, refrigerator 1 can increase the enthalpy of the refrigerant (state C1) drawn into compressor 24 by difference Δq. This allows refrigerator 1 to increase the enthalpy of the refrigerant (state C2) protruding from compressor 24. This allows refrigerator 1 to increase the amount of heat released (amount of heat) from the refrigerant used to heat freezing evaporator 14b.

[0130] In addition, by increasing the amount of heat radiation (amount of heat) and reducing the required compression power (power consumption wa) of the compressor 24, the refrigerator 1 can improve the heating efficiency (ratio of the amount of heat in the refrigeration evaporator 14b to the amount of power consumption) using a refrigerant such as isobutane, i.e., improve energy-saving performance.

[0131] Furthermore, refrigerator 1 cools refrigerator compartment 2 by heat absorption amount qc even during defrosting operation, and even if the cooling amount is qc, the enthalpy of the refrigerant increases by Δq due to internal heat exchanger 58. That is, refrigerator 1 obtains the effects of improving the cooling capacity and energy saving performance due to internal heat exchanger 58.

[0132] In this embodiment, heat exchange occurs between the refrigerant pipe F6 downstream of the branching point 56 and each of the capillary tubes 53a, 53b, and 103. However, the effect of the internal heat exchanger 58 during defrosting operation can also be obtained by heat exchange between the defrosting capillary tube 103 and the refrigerant flow path from the refrigeration evaporator 14a to the branching point 56.

[0133] Based on the above description, the refrigerator 1 of this embodiment is configured as follows.

[0134] When defrosting operation is performed, the compressor has an internal heat exchange section 58 that exchanges heat between a refrigerant flow path FP8 from the freezing evaporator 14b to the refrigeration evaporator 14a and a refrigerant flow path FP6 from the refrigeration evaporator 14a to the compressor 24.

[0135] [Example 2] In this embodiment, a branch section 113 where the refrigerant flow path for defrosting operation and the refrigerant flow path for freezing and cooling operation join together is provided in the refrigerant flow path between the freezing capillary tube 53b and the freezing evaporator 14b, and a branch section 114 where the refrigerant flow path for defrosting operation and the refrigerant flow path for freezing and cooling operation branch off is provided in the refrigerant flow path between the freezing evaporator 14b and the freezing gas-liquid separator 54b2, so that the refrigerant flows to the freezing evaporator 14b in the same flow direction in both the freezing and cooling operation and the defrosting operation.

[0136] The configuration of the refrigeration cycle 203 of the refrigerator 1 of the second embodiment will be described below with reference to Fig. 10. Fig. 10 is a schematic diagram showing the configuration of the refrigeration cycle (refrigerant flow path) 203 of the refrigerator 1 of the second embodiment.

[0137] As in the first embodiment, the refrigeration cycle 203 of the second embodiment is configured such that, during defrosting operation, high-temperature refrigerant discharged from the compressor 24 flows through the refrigerant pipe 59 of the freezing evaporator 14b, thereby heating and melting frost adhering to the freezing evaporator 14b, and cooling and absorbing heat from the refrigerator compartment 2 by the refrigeration evaporator 14a.

[0138] Specifically, the refrigerant flow paths are as follows: The refrigerant flow paths FP1, FP2, FP3, FP4, and FP6 are the same as those in the first embodiment, and therefore will not be described.

[0139] Refrigerant flow path FP35 is configured to connect three-way valve 52 and branch portion 56 through refrigeration capillary tube 53b, branch portion 113, piping conversion portion 121, refrigeration evaporator 14b, piping conversion portion 123, branch portion 114, two-way valve 112, check valve 55, and refrigeration gas-liquid separator 54b2. Refrigerant flow path FP35 includes refrigerant flow path FP35a connecting three-way valve 52 and branch portion 113, refrigerant flow path FP35b connecting branch portion 113 and piping conversion portion 121, refrigerant flow path 35c connecting piping conversion portion 123 and branch portion 114, and refrigerant flow path 35d connecting branch portion 114 and branch portion 56. Like piping conversion portions 121 and 122 of the first embodiment, piping conversion portion 123 is a conversion portion that allows aluminum piping and copper piping to be connected. The refrigerant pipes (refrigerant flow paths FP35c, FP35d, and FP6) downstream of the pipe conversion unit 123 are all made of copper, and the refrigeration gas-liquid separator 54b2 is also made of copper. Although not shown, the refrigeration gas-liquid separator 54b2 of the second embodiment together with the check valve 55 are provided in a foam insulation material (insulated box 10).

[0140] The refrigerant flow path FP37 is configured to connect the three-way valve 101 and the branching portion 113. The branching portion 113 is a portion where the refrigerant flow path FP37 and the refrigerant flow path FP35 join (connect).

[0141] The refrigerant flow path FP38 is configured to connect the branching portion 114 to the branching portion 105, passing through the defrosting capillary tube 103 and the check valve 104. The branching portion 114 is a portion configured to branch the refrigerant flow path FP38 from the refrigerant flow path FP35. The order of the defrosting capillary tube 103 and the check valve 104 may be reversed.

[0142] The refrigeration cycle 203 is configured to connect a branch point 113 provided in the refrigerant flow path between the refrigeration capillary tube 53b and the refrigeration evaporator 14b to an outlet 101b of the three-way valve 101 via a refrigerant flow path FP37. The refrigeration cycle 203 is also configured to connect a branch point 114 provided downstream of the refrigeration evaporator 14b to the defrosting capillary tube 103 via a refrigerant flow path FP38. The refrigeration cycle 203 is also configured such that a piping on the refrigerant path connecting the refrigeration evaporator 14a and the compressor 24 and a piping on the refrigerant path connecting the refrigeration evaporator 14b and the compressor 24 merge (connect) at a branch point 56. The refrigeration cycle 203 is also provided with a two-way valve 112 between the branch point 114 and the branch point 56. The two-way valve 112 is open during refrigeration / cooling operation and closed during defrosting operation.

[0143] The other parts of the refrigeration cycle 203 of the second embodiment are the same as those of the refrigeration cycle 200 of the first embodiment (FIG. 5).

[0144] During defrosting operation, the refrigeration cycle 203 opens the outlet 101b side of the three-way valve 101 and closes the two-way valve 112. This allows high-temperature refrigerant from the compressor 24 to flow directly through the refrigerant pipe 59 of the freezing evaporator 14b and heat the freezing evaporator 14b. Since the two-way valve 112 side is closed, the refrigerant thereafter flows to the defrosting capillary tube 103 side and absorbs heat in the refrigeration evaporator 14a.

[0145] In this way, the refrigeration cycle 203, like the first embodiment, heats the freezing evaporator 14b with the high-temperature refrigerant from the compressor 24, and during this time, the refrigeration evaporator 14a absorbs heat, thereby realizing a defrosting operation. That is, the refrigeration cycle 203 has a defrosting operation in which the high-temperature refrigerant heats the freezing evaporator 14b while utilizing the cooling of the refrigerator compartment 2 as heat absorption, and heat exchange with the freezing evaporator 14b is performed using the same refrigerant piping during the defrosting operation and the freezing / cooling operation. The refrigeration cycle state (Ph diagram) is also basically the same as the refrigeration cycle state of the first embodiment shown in Fig. 7. Therefore, the refrigeration cycle 203 can obtain the main effects of the first embodiment.

[0146] Based on the above description, the refrigerator 1 of this embodiment is configured as follows. A refrigeration gas-liquid separator 54b2 is provided to separate the refrigerant that has passed through the refrigeration evaporator 14b into gas and liquid. The refrigeration gas-liquid separator 54b2 is provided in the refrigerant flow path from the refrigeration evaporator 14b to the first branch portion 56 during the refrigeration / cooling operation. The refrigerant flow path for the defrosting operation has a second branch portion 113 that joins the refrigerant flow paths FP35a and FP35b for the freezing and cooling operation between the first pressure reducing portion 53b and the freezing evaporator 14b, and a third branch portion 114 that branches off to the refrigerant flow paths FP35c and FP35d for the freezing and cooling operation between the freezing evaporator 14b and the first branch portion 56, The third branch portion 114 is provided at a location closer to the refrigeration evaporator 14b than the refrigeration gas-liquid separator 54b and the third refrigerant control portion 112 are.

[0147] The refrigerator 1 also includes a third decompression unit 103 that decompresses the refrigerant. The refrigerant flow path for the defrosting operation has a second branch portion 113 that joins the refrigerant flow paths FP35a and FP35b for the freezing and cooling operation between the first pressure reducing portion 53b and the freezing evaporator 14b, and a third branch portion 114 that branches off to the refrigerant flow paths FP35c and FP35d for the freezing and cooling operation between the freezing evaporator 14b and the first branch portion 56, The third pressure reducing section 103 is provided in a refrigerant flow path FP8 that connects the third branching section 110 and the refrigeration evaporator 14a in the defrosting operation.

[0148] <Comparison with Example 1> When the refrigerant flows through the freezing evaporator 14b in the same flow direction in the freezing / cooling operation and the defrosting operation as in the second embodiment, the following considerations are required for the freezing gas-liquid separator 54b2.

[0149] During defrosting operation, when the refrigerant that has flowed through the freezing evaporator 14b is passed through the freezing gas-liquid separator 54b2, the refrigerant condensed in the freezing evaporator 14b becomes a gas refrigerant with a relatively high specific enthalpy in the freezing gas-liquid separator 54b2 (a refrigerant on or to the right of the saturated vapor line in FIG. 7). Even when this refrigerant reaches the refrigeration evaporator 14a, its high specific enthalpy prevents it from sufficiently cooling or absorbing heat in the refrigeration evaporator 14a. Therefore, it is necessary to bypass the freezing gas-liquid separator 54b2 so that the liquid refrigerant (including two-phase gas-liquid refrigerant) condensed in the freezing evaporator 14b flows to the refrigeration evaporator 14a. For this reason, in this embodiment, a branch section 114 is provided between the freezing evaporator 14b and the freezing gas-liquid separator 54b2.

[0150] On the other hand, since the refrigeration gas-liquid separator 54b2 is bypassed, the refrigeration cycle 203 of this embodiment cannot perform highly efficient heating and defrosting of the refrigeration gas-liquid separator 54b by directly flowing the refrigerant through the refrigeration gas-liquid separator 54b as described in the first embodiment.

[0151] <Disposing the refrigeration gas-liquid separator 54b2 inside the heat insulating member> As described above, in the second embodiment, the branching portion 114, the two-way valve 112, and the check valve 55 must be disposed between the refrigeration evaporator 14b and the refrigeration gas-liquid separator 54b2, which means that the refrigeration evaporator 14b and the refrigeration gas-liquid separator 54b2 are disposed apart from each other. Furthermore, if the refrigeration gas-liquid separator 54b2 were made of copper, there would be little advantage to disposing the refrigeration evaporator 14b and the refrigeration gas-liquid separator 54b2 close to each other. For this reason, in the second embodiment, the refrigeration gas-liquid separator 54b2 is disposed within the foam insulation material (insulated box 10). This prevents the refrigeration gas-liquid separator 54b2 from coming into contact with air and forming frost due to moisture in the air. Therefore, defrosting of the refrigeration gas-liquid separator 54b2 is not required.

[0152] Based on the above, in the refrigerator 1 of this embodiment, the freezing gas-liquid separator 54b2 is provided inside the heat insulating member.

[0153] <Modification of Example 2> A refrigeration cycle 204 which is a first modification of the second embodiment will be described with reference to Fig. 11A. Fig. 11A is a schematic diagram showing a first modification of the refrigeration cycle (refrigerant flow path) 106 of the second embodiment. As described above, since there is little advantage to arranging a gas-liquid separator near the freezing evaporator 14b, as shown in Fig. 11A, the gas-liquid separator 54c may be provided in the refrigerant flow path FP6 downstream from the branching portion 56. In this embodiment, the gas-liquid separator 54c is provided in the refrigerant flow path between the branching portion 56 and the internal heat exchange portion 58, instead of the freezing gas-liquid separators 54b, 54b2 and the refrigerating gas-liquid separator 54a.

[0154] In this location, the gas-liquid separator 54c can separate the refrigerant from the refrigeration evaporator 14a into gas and liquid, in addition to separating the refrigerant that has passed through the freezing evaporator 14b during the freezing / cooling operation, and can also separate the refrigerant from the refrigeration evaporator 14a into gas and liquid during the refrigeration / cooling operation and the defrosting operation. Therefore, the single gas-liquid separator 54c can suppress the inflow of liquid refrigerant into the compressor 24 under all operating conditions.

[0155] The reason why the gas-liquid separator 54c is arranged upstream of the internal heat exchanger 58 (on the evaporators 14a, 14b side) is that if the refrigerant flowing into the internal heat exchanger 58 changes from a gas phase to a two-phase gas-liquid phase, the heat exchange performance in the internal heat exchanger 58 may change suddenly, resulting in unstable operation. That is, to stabilize the heat exchange performance in the internal heat exchanger 58, the gas-liquid separator 54c is arranged upstream of the internal heat exchanger 58, so that the refrigerant flowing into the internal heat exchanger 58 is only a gas refrigerant.

[0156] Based on the above, the refrigerator 1 of this embodiment is provided with a gas-liquid separator 54c that separates the refrigerant that has passed through the freezing evaporator 14b into gas and liquid and the refrigerant that has passed through the refrigerating evaporator 14a into gas and liquid, and the gas-liquid separator 54c is provided upstream of the internal heat exchanger 58.

[0157] In the second embodiment, the order of the refrigeration gas-liquid separator 54b2, the two-way valve 112, and the check valve 55 may be different, but they must be arranged as follows.

[0158] The two-way valve 112 needs to be provided in the range from the branch point 114 to the branch point 56. This is because, as in the case of the first embodiment, during defrosting operation, the refrigerant is allowed to flow from the refrigeration evaporator 14a to the compressor 24 while bypassing the refrigeration evaporator 14a and preventing the refrigerant from flowing into the refrigerant flow path FP6.

[0159] A refrigeration cycle 205 which is Modification 2 of Embodiment 2 will be described with reference to Fig. 11B. Fig. 11B is a schematic diagram showing Modification 2 of a refrigeration cycle (refrigerant passage) 203 of Embodiment 2. 9A and 9B, a refrigerant control valve such as a three-way valve may be used in the branching portion instead of the two-way valve 112. Specifically, the refrigeration cycle 205 is not provided with the two-way valve 112, and is provided with a three-way valve 214 in place of the branching portion 114. The three-way valve 214 is controlled so that during the freezing and cooling operation, the refrigerant flow paths FP35c and FP35d communicate with each other and the FP38 side is closed, and during the defrosting operation, the refrigerant flow paths FP35c and FP38 communicate with each other while the refrigerant flow paths FP35d side is closed.

[0160] 11C, a refrigeration cycle 206 which is a third modification of the second embodiment will be described. FIG. 11C is a schematic diagram showing the third modification of the refrigeration cycle (refrigerant flow path) 106 of the second embodiment. The refrigeration cycle 206 of the third modified example does not include the two-way valve 112, and is provided with a three-way valve 256a instead of the branching unit 56. The three-way valve 256a is controlled to communicate between the refrigerant flow paths FP35d and FP6 and close the refrigerant flow path FP4 during the freezing and cooling operation, and to communicate between the refrigerant flow paths FP4b and FP6 while closing the refrigerant flow path FP35d during the defrosting operation.

[0161] As described above, the refrigeration gas-liquid separator 54b2 must be provided downstream of the branching portion 114 (on the refrigerant flow path FP6 side) in the refrigerant flow path up to the compressor 24. However, as described above, it is desirable to provide it upstream of the internal heat exchanger 58 (on the evaporators 14a, 14b side).

[0162] When the check valve 55 is provided as in the first and second modifications of the second embodiment, the check valve 55 needs to be provided between the freezing evaporator 14b and the branching portion 56. This is to prevent the refrigerant from flowing into the freezing evaporator 14b during refrigeration / cooling operation. However, although the freezing gas-liquid separator 54b2 is provided in the foam insulation in the second embodiment, if the freezing gas-liquid separator 54b2 is provided in a space in the freezing temperature range, such as the freezing compartment 7 or the freezing evaporator chamber 8b, the check valve 55 is preferably provided downstream of the freezing gas-liquid separator 54b2. This is because, if the freezing gas-liquid separator 54b2 is provided in a space in the freezing temperature range and the refrigerant flow path to the freezing gas-liquid separator 54b2 is open, the gas refrigerant that has passed through the refrigeration / cooling separator 54a flows into the freezing gas-liquid separator 54b2, condensing the refrigerant and causing the refrigerant to accumulate in the freezing gas-liquid separator 54b2. To avoid this, a check valve 55 is provided between the refrigeration gas-liquid separator 54b2 and the branching portion 56, thereby blocking the refrigerant flow path from the branching portion 56 to the refrigeration gas-liquid separator 54b2.

[0163] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of the embodiments with other configurations, and it is also possible to add other configurations to the configuration of the embodiments. Furthermore, it is possible to add, delete, or replace part of each configuration with other configurations.

[0164] For example, the pressure reducer 53, 103 of the refrigerator 1 may be provided with a pressure-controllable expansion valve (not shown) instead of a capillary tube. Such a refrigerator can adjust the pressure of the refrigerant as needed. Also, the pressure reducer 103 may be a refrigerant pipe.

[0165] Furthermore, the opening and closing states of the various valves in the present invention do not necessarily have to be two states, open and closed, but valves whose opening amount can be adjusted in stages, such as fully open, half open, closed, etc., may also be used.

[0166] Furthermore, compressor 52 having two discharge ports may be used as the first refrigerant control unit instead of three-way valve 101. During defrosting operation, the refrigerant may be discharged to refrigerant flow paths FP7 and FP37, and during freezing / cooling operation or refrigeration / cooling operation, the refrigerant may be discharged to refrigerant flow path FP2.

[0167] Furthermore, although the above-described embodiment discloses a defrosting operation using a refrigerant, a defrosting mode in which an electric heater provided below the freezing evaporator 14b generates heat may also be used in combination. [Explanation of symbols]

[0168] 1...refrigerator, 2...refrigeration compartment, 7...freezer compartment, 14a...refrigeration evaporator, 14b...freezing evaporator, 24...compressor, 50...heat dissipation section, 52...second refrigerant control section, 53a...second pressure reduction section, 53b...first pressure reduction section, 54b, 54b2...freezing gas-liquid separator, 54c...gas-liquid separator, 56...first branch section, 58...internal heat exchange section, 59...refrigerant piping, 101...first refrigerant control section, 103...third pressure reduction section, 110, 114...third branch section, 111, 113...second branch section, 112, 211, 214, 256...third refrigerant control section, 130...hole.

Claims

1. A refrigerator compartment and a refrigeration evaporator for cooling the refrigeration compartment; A freezer and a refrigeration evaporator for cooling the freezing compartment; a compressor that compresses a refrigerant; a heat dissipation unit that dissipates heat from the refrigerant; a first pressure reducing section and a second pressure reducing section that reduce the pressure of the refrigerant; a first branch portion provided in the refrigerant flow path; a first refrigerant control unit, a second refrigerant control unit, and a third refrigerant control unit that perform at least one of switching and closing of a refrigerant flow path; In a freezing and cooling operation for cooling the freezing compartment, a refrigerant flow path is configured so that the refrigerant discharged from the compressor flows in the order of the first refrigerant control unit, the heat radiating unit, the second refrigerant control unit, the first decompression unit, the freezing evaporator, the third refrigerant control unit, and the first branching unit, and returns to the compressor to cool the freezing evaporator, In a defrosting operation for melting frost on the freezing evaporator, the third refrigerant control unit closes a refrigerant flow path that bypasses the refrigeration evaporator from the freezing evaporator and returns to the compressor, and the refrigerant flow path is configured so that the refrigerant discharged from the compressor flows through the first refrigerant control unit, the freezing evaporator, and the refrigeration evaporator in this order, and returns to the compressor, thereby heating the freezing evaporator. The refrigerator in which a refrigerant flow path that exchanges heat with the freezing evaporator in the defrosting operation and a refrigerant flow path that exchanges heat with the freezing evaporator in the freezing / cooling operation are configured with the same refrigerant piping.

2. The refrigerator according to claim 1, a refrigeration gas-liquid separator for separating the refrigerant that has passed through the refrigeration evaporator into gas and liquid; the refrigeration gas-liquid separator is provided in a refrigerant flow path from the refrigeration evaporator to the third refrigerant control unit during the refrigeration and cooling operation, the refrigerant flow path for the defrosting operation has a second branch portion that merges with the refrigerant flow path for the freezing / cooling operation between the first refrigerant control unit and the freezing evaporator, and a third branch portion that branches from the refrigerant flow path for the freezing / cooling operation between the freezing evaporator and the first decompression unit, the second branch portion is provided between the refrigeration gas-liquid separator and the first branch portion, The third refrigerant control unit is provided in a range from the second branch unit to the first branch unit.

3. The refrigerator according to claim 2, The refrigerant pipe on the side of the refrigeration evaporator, which is provided inside the refrigeration gas-liquid separator, has a tip that is provided higher than a lower end inside the refrigeration gas-liquid separator and has a hole that allows refrigerant to flow from the refrigeration gas-liquid separator to the side of the refrigeration evaporator.

4. The refrigerator according to claim 1, a refrigeration gas-liquid separator for separating the refrigerant that has passed through the refrigeration evaporator into gas and liquid; the refrigeration gas-liquid separator is provided in a refrigerant flow path from the refrigeration evaporator to the first branch portion during the refrigeration cooling operation, the refrigerant flow path for the defrosting operation has a second branch portion that merges with the refrigerant flow path for the freezing / cooling operation between the first decompression portion and the freezing evaporator, and a third branch portion that branches from the refrigerant flow path for the freezing / cooling operation between the freezing evaporator and the first branch portion, The refrigerator, wherein the third branch portion is provided at a location closer to the freezing evaporator than the freezing gas-liquid separator and the third refrigerant control portion.

5. The refrigerator according to claim 4, The refrigerator, wherein the refrigeration gas-liquid separator is provided inside a heat insulating member.

6. The refrigerator according to claim 1, a third pressure reducing section that reduces the pressure of the refrigerant; the refrigerant flow path for the defrosting operation includes a second branch portion that merges with the refrigerant flow path for the freezing / cooling operation between the first refrigerant control portion and the freezing evaporator in the refrigerant flow in the defrosting operation, and a third branch portion that branches from the refrigerant flow path for the freezing / cooling operation between the freezing evaporator and the first decompression portion, The third pressure reducing section is provided in a refrigerant flow path that connects the third branch section and the refrigeration evaporator in the defrosting operation.

7. The refrigerator according to claim 1, a third pressure reducing section that reduces the pressure of the refrigerant; the refrigerant flow path for the defrosting operation has a second branch portion that merges with the refrigerant flow path for the freezing / cooling operation between the first decompression portion and the freezing evaporator, and a third branch portion that branches from the refrigerant flow path for the freezing / cooling operation between the freezing evaporator and the first branch portion, The third pressure reducing section is provided in a refrigerant flow path that connects the third branch section and the refrigeration evaporator in the defrosting operation.

8. The refrigerator according to claim 1, In a refrigeration cooling operation for cooling the refrigeration compartment, a refrigerant flow path is configured such that a refrigerant discharged from the compressor flows in the order of the first refrigerant control unit, the heat radiating unit, the second refrigerant control unit, the second decompression unit, the refrigeration evaporator, and the first branch unit, and returns to the compressor to cool the refrigeration evaporator, The refrigerator is configured such that a flow resistance of a refrigerant flow path connecting the freezing evaporator to the refrigeration evaporator in the defrosting operation is smaller than a flow resistance of a refrigerant flow path connecting an outlet of the heat radiating section to the refrigeration evaporator in the refrigeration cooling operation.

9. The refrigerator according to claim 1, a refrigerator having an internal heat exchange unit that performs heat exchange between a refrigerant flow path from the freezing evaporator to the refrigerating evaporator and a refrigerant flow path from the refrigerating evaporator to the compressor when the defrosting operation is performed.

10. The refrigerator according to claim 9, a gas-liquid separator for performing gas-liquid separation of the refrigerant that has passed through the freezing evaporator and gas-liquid separation of the refrigerant that has passed through the refrigeration evaporator; The gas-liquid separator is provided upstream of the internal heat exchanger.

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