refrigerator

Abstract

To provide a refrigerator capable of defrosting in a short time with higher heating efficiency.SOLUTION: A refrigerator 1 includes: a compressor 24 for compressing a refrigerant; heat release means 50 for releasing heat from the refrigerant; evaporator for refrigeration (R evaporator 14a) which evaporates the refrigerant during a refrigeration / cooling operation; evaporator for freezing (F evaporator 14b) for evaporating the refrigerant during the refrigeration / cooling operation; and a pipe 102 for defrosting arranged inside or in the vicinity of the evaporator for freezing, and for performing heat exchange between it and the evaporator for freezing during a defrosting operation. Flow passage resistance R1 of a refrigerant path FP8 connecting from an outlet Out 102 of the pipe 102 for defrosting to an inlet In 14a of the evaporator for refrigeration is set to be lower than flow passage resistance R2 of refrigerant paths FP3, FP4a connecting from an outlet Out 50 of the heat release means 50 to the inlet In 14a of the evaporator for refrigeration.SELECTED DRAWING: Figure 6C

Description

[Technical field]

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

[0002] Conventionally, techniques related to refrigerators are described in, for example, Patent Document 1 and Patent Document 2. Patent Document 1 and Patent Document 2 describe refrigerators that perform a defrosting operation to remove frost adhering to a freezer cooler by heating a refrigerant in a freezer cooler (first cooler) using heat radiation from a refrigeration cycle and flowing the refrigerant into a refrigerating cooler (second cooler). The freezer cooler is a cooler used in an operation to cool a freezer compartment (freezer cooling operation). The refrigerating cooler is a cooler used in an operation to cool a refrigerating compartment (refrigerating cooling operation). These conventional refrigerators can cool the refrigerating compartment during the defrosting operation, and can use the heat obtained by the refrigerant during the defrosting operation to heat the freezer cooler, so that defrosting can be performed more efficiently than defrosting using an electric heater. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6687384 [Patent Document 2] JP 2019-215147 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the refrigerator described in Patent Document 1 and the refrigerator described in Patent Document 2 tend to require a long defrosting time for the following reasons, and there is a demand for defrosting with even higher heating efficiency.

[0005] For example, the refrigerator described in Patent Document 1 flows the refrigerant from the downstream side of the first heat dissipation means into the defrost pipe. Therefore, the refrigerant flowing into the defrost pipe has a reduced heat quantity. The defrost pipe is described as a refrigerant flow path branched from a high-temperature side refrigerant flow path through which a high-temperature liquid refrigerant flows. Therefore, the refrigerant flowing into the defrost pipe releases at least the amount of heat until the gas refrigerant immediately after being discharged from the compressor becomes a gas-liquid state. Therefore, the refrigerant flowing into the defrost pipe is liquefied at the time of inflow, and therefore the amount of heat that can be dissipated is small. Therefore, in the refrigerator described in Patent Document 1, the amount of heat that can be used to heat the freezing cooler (first cooler) by the defrost pipe is small, and the defrosting time is likely to be long.

[0006] In addition, since at least a part of the refrigerant flowing into the defrosting pipe is liquefied, the first heat dissipation means exchanges heat before the refrigerant flows into the defrosting pipe, so that the condensation temperature is higher than the outside temperature. That is, in the refrigerator described in Patent Document 1, the refrigerant is condensed at a point where the refrigerant exchanges heat with the outside air, and the refrigerant dissipates heat to the outside air at that point. At that time, the refrigerant dissipates heat, so the temperature of the refrigerant is higher than the outside air. That is, the refrigerant reaches the condensation temperature by dissipating heat, so the condensation temperature of the refrigerant is higher than the temperature of the outside air. For defrosting, it is sufficient for the temperature of the refrigerant to exceed the freezing point temperature, but in order to make the condensation temperature higher than the outside temperature, that is, to increase the pressure of the refrigerant to a high condensation pressure, the compressor's workload increases. This reduces the heating efficiency of the refrigerator (the amount of heat applied to the freezing cooler (first cooler) relative to the amount of power consumption). Therefore, it is desired that the refrigerator be defrosted in a short time with even higher heating efficiency.

[0007] On the other hand, in the refrigerator described in Patent Document 2, the refrigerant immediately after being discharged from the compressor flows into the defrost pipe, but the return point of this defrost pipe is before the cooling switching valve. In addition, in the refrigerator described in Patent Document 2, a pressure reducing device used during cooling is connected downstream of the cooling switching valve. In such a refrigerator described in Patent Document 2, when the refrigerant flows through the defrost pipe, the heat dissipation means is only the defrost pipe, and the expansion means is the pressure reducing device used for refrigerating and cooling. When the heat dissipation means is only the defrost pipe, the condensation temperature becomes close to the heat exchange target of the defrost pipe (the refrigeration cooling device (first cooling device) with frost). Therefore, there is a possibility that the condensation temperature becomes close to the freezing point temperature, that is, the condensation pressure becomes lower than that during refrigerating and cooling. When the pressure is reduced by the pressure reducing device for refrigerating and cooling from a low condensing pressure, the evaporation pressure is excessively reduced. Therefore, the pressure of the gas refrigerant sucked into the compressor decreases. When the pressure of the gas refrigerant is low, the density of the refrigerant is low, the amount of refrigerant circulating is small relative to the displacement amount and the rotation speed of the compressor, and the amount of heat that can be used to heat the freezing cooler (first cooling unit) is small. Also, because the pressure of the gas refrigerant sucked into the compressor is low, the amount of work done by the compressor to increase the pressure to condense (more precisely, the amount of work per amount of refrigerant circulating) is large, and the heating efficiency is low. For this reason, it is desirable for refrigerators to defrost in a short time with even higher heating efficiency.

[0008] The present invention has been made to solve the above-mentioned problems, and has as its main object to provide a refrigerator capable of defrosting in a short time with high heating efficiency. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides a refrigerator comprising: a refrigerator compartment; a freezer compartment; a compressor that compresses a refrigerant; heat dissipation means for discharging heat from the refrigerant; a refrigeration evaporator that evaporates the refrigerant during a refrigeration / cooling operation for cooling the refrigerator compartment; a freezing evaporator that evaporates the refrigerant during a freezing / cooling operation for cooling the freezing compartment; and a defrosting pipe that is disposed inside or near the freezing evaporator and performs heat exchange with the freezing evaporator, and is configured such that, during a defrosting operation, refrigerant discharged from the compressor is caused to flow through the defrosting pipe, the refrigeration evaporator, and the compressor in this order to heat the freezing evaporator and remove frost adhering to the freezing evaporator, and a flow resistance of a refrigerant path connecting an outlet of the defrosting pipe to an inlet of the refrigeration evaporator is set lower than a flow resistance of a refrigerant path connecting an outlet of the heat dissipation means to an inlet of the refrigeration evaporator. Other means will be described later. Effect of the Invention

[0010] According to the present invention, it is possible to provide a refrigerator capable of defrosting in a short time and with high heating efficiency. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a front view showing the configuration of a refrigerator according to a first embodiment. [Diagram 2] 2 is a cross-sectional view taken along line X1-X1 shown in FIG. [Diagram 3] 3 is a cross-sectional view taken along line X2-X2 shown in FIG. 2. [Figure 4A] FIG. 2 is a perspective view showing a configuration of an F evaporator in the refrigerator of the first embodiment. [Figure 4B] FIG. 2 is an enlarged side view showing the configuration of fins of an F evaporator in the refrigerator of the first embodiment. [Diagram 5] 1 is a schematic diagram showing a configuration of a refrigeration cycle (refrigerant flow path) in a refrigerator of a first embodiment. [Figure 6A] FIG. 4 is an explanatory diagram showing a flow of a refrigerant during a refrigeration cooling operation (R cooling operation) in the refrigerator of the first embodiment. [Figure 6B]It is an explanatory diagram showing the flow of refrigerant during the freezing and cooling operation (F cooling operation) in the refrigerator of the first embodiment. [Figure 6C] It is an explanatory diagram showing the flow of refrigerant during the defrosting operation in the refrigerator of the first embodiment. [Figure 7] It is a P-h diagram representing the state of the refrigeration cycle during the defrosting operation. [Figure 8] It is a schematic diagram showing the refrigeration cycle (refrigerant flow path) of the first comparative example. [Figure 9] It is a schematic diagram showing the refrigeration cycle (refrigerant flow path) of the second comparative example. [Figure 10] It is a P-h diagram representing the states of the refrigeration cycle of the first embodiment, the refrigeration cycle of the first comparative example, and the refrigeration cycle of the second comparative example during the defrosting operation. [Figure 11] It is a schematic diagram showing the configuration of the refrigeration cycle (refrigerant flow path) in the refrigerator of the second embodiment.

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments 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 only schematically shows the present invention to such an extent that it can be sufficiently understood. Therefore, the present invention is not limited to only the illustrated examples. Also, in each drawing, common components and similar components are denoted by the same reference numerals, and redundant descriptions thereof are omitted.

[0013] [First Embodiment] <Overall Configuration of Refrigerator 1> Hereinafter, with reference to FIGS. 1 to 3, the configuration of the refrigerator 1 of the first embodiment will be described. FIG. 1 is a front view showing the configuration of the refrigerator 1 of the first embodiment. FIG. 2 is a cross-sectional view taken along line X1-X1 shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line X2-X2 shown in FIG. 2. In the following description, a 6-door refrigerator 1 will be taken as an example for explanation, but the refrigerator 1 is not limited to 6 doors.

[0014] The refrigerator 1 has the function of performing refrigeration / cooling operation, freezing / cooling operation, and defrosting operation. The refrigeration / cooling operation is an operation for cooling the refrigerator compartment 2 (FIG. 1) described later. The freezing / cooling operation is an operation for cooling the freezer compartment 7 (FIG. 1) described later. The defrosting operation is an operation for removing frost adhering to the F evaporator 14b (FIGS. 2 and 3) described later (and thus to the freezer compartment 7 (FIG. 1) described later).

[0015] In the following description, "refrigerated cooling" may be referred to as "R cooling" and "refrigerated cooling operation" may be referred to as "R cooling operation". Furthermore, "freezing cooling" may be referred to as "F cooling" and "freezing cooling operation" may be referred to as "F cooling operation". Furthermore, refrigerated cooling operation and freezing cooling operation may be collectively referred to as "cooling operation". Furthermore, components related to "refrigerated cooling operation" will be described with "R" meaning "refrigerated cooling" at the beginning. Furthermore, components related to "freezing cooling operation" will be described with "F" meaning "freezing cooling" at the beginning.

[0016] As shown in FIG. 1, the insulated box 10 of the refrigerator 1 has storage compartments in the order of the refrigerator compartment 2, the ice-making compartment 3, the upper freezer compartment 4, the lower freezer compartment 5, and the vegetable compartment 6, which are arranged on the left and right sides in this order from above. The refrigerator 1 is equipped with doors that open and close the openings of each storage compartment. These doors are the left and right divided rotating doors 2a and 2b of the refrigerator compartment 2 that open and close the opening of the refrigerator compartment 2, and the pull-out door 3a of the ice-making compartment 3, the door 4a of the upper freezer compartment 4, the door 5a of the lower freezer compartment 5, and the door 6a of the vegetable compartment 6 that open and close the openings of the ice-making compartment 3, the upper freezer compartment 4, the lower freezer compartment 5, and the vegetable compartment 6, respectively. Door hinges (not shown) are provided at the top and bottom of the refrigerator compartment 2 to fix the doors 2a and 2b of the refrigerator compartment 2 to the refrigerator 1, and the upper door hinge is covered with a door hinge cover 16.

[0017] The refrigerator compartment 2 and the vegetable compartment 6 are refrigerated storage compartments whose interiors are basically controlled to the refrigeration temperature range (above 0°C), for example, the refrigerator compartment 2 is controlled to about 4°C, and the vegetable compartment 6 is controlled to about 6°C. The ice-making compartment 3, the upper freezer compartment 4, and the lower freezer compartment 5 are freezer storage compartments whose interiors are controlled to a freezing temperature range (below 0°C), for example, about -20°C on average. In the following, the freezer storage compartments, the ice-making compartment 3, the upper freezer compartment 4, and the lower freezer compartment 5, are referred to as freezer compartment 7.

[0018] As shown in FIG. 2, the refrigerator 1 is configured such that the outside and the inside of the refrigerator are separated by the insulated box 10 formed by filling a space between an outer box 10a (made of steel plate) and an inner box 10b (made of synthetic resin) with a foam insulation material (e.g., urethane foam). In addition to a foam insulation material such as urethane foam, the insulated box 10 is provided with a vacuum insulation material 25 having a lower thermal conductivity than the foam insulation material between the outer box 10a and the inner box 10b, thereby improving the insulation performance without reducing the food storage volume. Here, the vacuum insulation material 25 is formed by wrapping a core material such as glass wool or urethane with an outer packaging material. The outer packaging material contains a metal layer (e.g., aluminum) to ensure gas barrier properties. The vacuum insulation material 25 is disposed on the ceiling wall, left and right walls, back wall, and bottom wall of the insulated box 10, and the vacuum insulation material 25 is also inserted into the door 5a of the lower freezer compartment 5, which is a relatively large freezer storage compartment, to improve the insulation performance.

[0019] The refrigerator compartment 2, the ice making compartment 3, and the upper freezer compartment 4 are separated by a heat insulating partition wall 28. The lower freezer compartment 5 and the vegetable compartment 6 are separated by a heat insulating partition wall 29. A heat insulating partition wall 30 is provided on the front side between the ice making compartment 3, the upper freezer compartment 4, and the lower freezer compartment 5 to prevent air in the refrigerator 1 from leaking out of the compartment through the gaps between the doors 3a, 4a, and 5a, and to prevent air from the outside from entering each storage compartment. In the first embodiment, an electric heater (not shown) for heating the vegetable compartment 6 is provided below the heat insulating partition wall 29 to prevent the vegetable compartment 6 from becoming too cold.

[0020] Doors 2a and 2b of refrigerator compartment 2 are provided with a plurality of door pockets 33a, 33b, and 33c on the inside of the refrigerator compartment. The interior of refrigerator compartment 2 is divided into a plurality of storage spaces by shelves 34a, 34b, 34c, and 34d. A low-temperature storage space 36 is provided in the lower part of refrigerator compartment 2 (above heat-insulating partition wall 28). Internal storage compartment 35 is a substantially sealed space whose interior is kept at a particularly low temperature of about -1 to +1°C, and to which no cold air is directly blown into internal storage compartment 35, and serves as a space for storing foods (such as meat and fish) that require prevention of drying at low temperatures.

[0021] 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 integrally with the doors 3a, 4a, 5a and 6a, respectively.

[0022] The R evaporator 14a, which is a refrigeration evaporator (cooler), is housed in the R evaporator chamber 8a, which is a refrigeration evaporator chamber. The R evaporator chamber 8a is formed by an R air passage component 61 provided at the rear of the refrigerator chamber 2 and an inner box 10b. The air in the R evaporator chamber 8a, which has been cooled by heat exchange with the R evaporator 14a, is sent from the refrigerator chamber outlet 11a provided in the R air passage component 61 to the refrigerator chamber 2 by the R fan 9a, which is a refrigerator fan provided above the R evaporator 14a, via the refrigerator chamber air passage 11, and cools the inside of the refrigerator chamber 2. The air sent to the refrigerator chamber 2 returns to the R evaporator chamber 8a from the refrigerator chamber return ports 15a, 15b (FIG. 3) provided in the R air passage component 61, and is cooled again by the R evaporator 14a.

[0023] Refrigerator compartment discharge outlet 11a is provided mainly in the upper part of refrigerator compartment 2. Refrigerator compartment return outlets 15a, 15b are provided in the lower part of refrigerator compartment 2, with refrigerator compartment return outlet 15a being provided on the lowest level of refrigerator compartment 2 (between shelf 34d and heat-insulating partition wall 28) and approximately at the rear of internal storage compartment 35, and refrigerator compartment return outlet 15b being provided on the second level from the bottom of refrigerator compartment 2 (between shelves 34c and 34d).

[0024] The F evaporator 14b, which is a freezing evaporator (cooler), is housed in the F evaporator chamber 8b, which is a freezing evaporator chamber. The F evaporator chamber 8b is composed of an F air passage component 62 provided at the rear of the freezing chamber 7 and an inner box 10b. The air in the F evaporator chamber 8b, which has been cooled by heat exchange with the F evaporator 14b, is sent to the freezing chamber 7 from the freezing chamber outlet 12a provided in the F air passage component 62 by the F fan 9b, which is a freezing fan provided above the F evaporator 14b, through the freezing chamber air passage 12, and cools the inside of the freezing chamber 7. The air sent to the freezing chamber 7 returns to the F evaporator chamber 8b from the freezing chamber return port 17 provided in the F air passage component 62, and is cooled again by the F evaporator 14b.

[0025] In the refrigerator 1 of the first embodiment, the vegetable compartment 6 is also cooled with air cooled by the F evaporator 14b. The air in the F evaporator chamber 8b cooled by the F evaporator 14b is sent to the vegetable compartment 6 by the F fan 9b through a vegetable compartment air duct (not shown) and a vegetable compartment damper (not shown) to cool the inside of the vegetable compartment 6. The low-temperature air generated by the F evaporator 14b is sent to the vegetable compartment 6, but the low-temperature air is prevented from directly entering the vegetable compartment container 6b that stores food, thereby preventing the vegetables from drying out. When the vegetable compartment 6 is at a low temperature, the vegetable compartment damper is closed to prevent the vegetable compartment 6 from being cooled. The air sent to the vegetable compartment 6 returns to the lower part of the F evaporator 14b through the vegetable compartment side cold air return air duct 18 provided in front of the lower part of the heat-insulating partition wall 29 from the vegetable compartment side cold air return air duct 18.

[0026] When moisture-containing air flows into the refrigerator due to opening and closing of the door, the moisture in the air turns into frost and adheres to the surfaces of the low-temperature R evaporator 14a and F evaporator 14b. As the frost grows, it impedes the heat exchange between the evaporator and the air, and the amount of air flowing through the evaporator decreases due to the ventilation resistance caused by the frost, so this refrigerator performs a defrosting operation to melt the frost on the evaporator.

[0027] The F evaporator 14b performs defrosting using the configuration described in Fig. 4A and subsequent figures. The defrosted water (melted water) generated during defrosting of the F evaporator 14b falls into the F drain 23b provided at the bottom of the F evaporator chamber 8b, and is discharged into the evaporation dish 32 provided at the top of the compressor 24 via the F drain port 22b and the F drain pipe 27b.

[0028] The R evaporator 14a performs defrosting by off-cycle defrosting, which circulates the air in the refrigerator compartment 2 and uses the heat of the refrigerator compartment 2 to perform defrosting. The defrosted water generated during defrosting of the R evaporator 14a falls into the R drain 23a provided at the bottom of the R evaporator chamber 8a, and is discharged into the evaporation tray 32 provided in the machine chamber 39 via the R drain port (not shown) and the R drain pipe (not shown).

[0029] 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.

[0030] A refrigerator temperature sensor 41, a freezer temperature sensor 42, and a vegetable temperature sensor 43 are provided on the interior rear side of the refrigerator compartment 2, the freezer compartment 7, and the vegetable compartment 6, respectively, and an R evaporator temperature sensor 40a is provided on the top of the R evaporator 14a, and an F evaporator temperature sensor 40b is provided on the top of the F evaporator 14b, and these sensors detect the temperatures of the refrigerator compartment 2, the freezer compartment 7, the vegetable compartment 6, the R evaporator 14a, and the F evaporator 14b. In addition, an outside air temperature sensor 37a that detects the temperature of the outside air (outside the refrigerator) and an outside air humidity sensor 37b that detects the humidity are provided inside the door hinge cover 16 on the ceiling of the refrigerator 1. As other sensors, door sensors (not shown) that detect the open / closed states of the doors 2a, 2b, 3a, 4a, 5a, and 6a, respectively, are also provided.

[0031] 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 a ROM (Read Only Memory) and a RAM (Random Access Memory), an interface circuit, etc. is disposed in a machine room 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, an R evaporator temperature sensor 40a, an F evaporator temperature sensor 40b, a door sensor, etc., by electrical wiring (not shown).

[0032] Also, in the control board 31, based on the output values of each sensor, the settings of the operation unit 26, the programs pre-recorded in the ROM, etc., the compressor 24, the R fan 9a, the F fan 9b, the machine room fan 38, and the vegetable room damper are controlled. The operation unit 26 is provided in the inner box 10b in the refrigerator compartment 2 (Fig. 2), and can give instructions for adjusting the temperatures of the refrigerator compartment 2, the freezer compartment 7, and the vegetable room 6, and for implementing additional functions, such as the rapid freezing function for enhancing the cooling capacity of the freezer compartment 7.

[0033] <Configuration of the F evaporator 14b> Hereinafter, with reference to Figs. 4A and 4B, the configuration of the F evaporator 14b will be described. Fig. 4A is a perspective view showing the configuration of the F evaporator 14b. Fig. 4B is an enlarged side view showing the configuration of the fins 120 of the F evaporator 14b.

[0034] As shown in Fig. 4A, the F evaporator 14b has an F evaporator refrigerant pipe 59 and fins 120. The F evaporator refrigerant pipe 59 is a refrigerant pipe from the refrigerant inflow portion of the F evaporator chamber 8b to the F gas-liquid separator 54b downstream of the F capillary tube 53b shown in Fig. 5 described later. The F evaporator 14b cools the air in the compartment by exchanging heat between the low-temperature refrigerant in the F evaporator refrigerant pipe 59 and the air during the cooling operation. The fins 120 are heat dissipation members for enhancing the heat exchange efficiency from the F evaporator refrigerant pipe 59 to the air. The fins 120 are provided so as to exchange heat with a defrosting pipe 102, which is a refrigerant pipe different from the F evaporator refrigerant pipe 59, in addition to the F evaporator refrigerant pipe 59. In the cycle defrosting described later, by flowing high-temperature refrigerant through this defrosting pipe 102, the fins 120, that is, the frost adhering to the F evaporator 14b, are heated to defrost the frost. Note that the F evaporator refrigerant pipe 59 and the defrosting pipe 102 are expanded to enhance the contact with the fins 120 in order to improve the heat transfer performance to the fins 120.

[0035] <Configuration and operation of the refrigeration cycle (refrigerant flow path) in the refrigerator 1> Hereinafter, the configuration and operation of the refrigeration cycle (refrigerant flow path) in the refrigerator 1 will be described 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) 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 (R cooling operation). Fig. 6B is an explanatory diagram showing the flow of the refrigerant in the refrigerator 1 during freezing cooling operation (F cooling operation). Fig. 6C is an explanatory diagram showing the flow of the refrigerant in the refrigerator 1 during defrosting operation.

[0036] 5, the refrigerator 1 includes a compressor 24, a heat dissipation means 50, a dryer 51, a three-way valve 52, a capillary tube 53, an R evaporator 14a, an F evaporator 14b, an R gas-liquid separator 54a, an F gas-liquid separator 54b, and a check valve 55. The refrigerator 1 also includes a three-way valve 101, a defrosting pipe 102, a defrosting capillary tube 103, and a check valve 104.

[0037] The compressor 24 is a component that compresses the refrigerant. The heat dissipation means 50 is a component that dissipates heat from the refrigerant. Here, the heat dissipation means 50 will be described as having an external radiator 50a and a wall surface heat dissipation pipe 50b that dissipate heat from the refrigerant, and a dew condensation prevention pipe 50c that suppresses dew condensation on the front surfaces of the heat insulating partition walls 28, 29, and 30. The dryer 51 is a component that removes moisture in the refrigeration cycle. The three-way valve 52 is a refrigerant control means for controlling whether the refrigerant flows to the R evaporator 14a side or the F evaporator 14b side. Hereinafter, the "three-way valve 52" may be referred to as the "first refrigerant control means." The three-way valve 52 includes an outlet 52a connected to the R capillary tube 53a via a refrigerant pipe, and an outlet 52b connected to the F capillary tube 53b via a refrigerant pipe, and can switch the outlet through which the refrigerant flows. The capillary tube 53 is a decompression means for decompressing the refrigerant. The capillary tube 53 includes an R capillary tube 53a (a capillary tube for refrigeration) for decompressing the refrigerant flowing on the R evaporator 14a side, and an F capillary tube 53b (a capillary tube for freezing) for decompressing the refrigerant flowing on the F evaporator 14b side. The R evaporator 14a is a refrigeration evaporator (cooler) that absorbs heat within the refrigeration compartment 2 by exchanging heat between the refrigerant and the air within the refrigeration compartment 2. The F evaporator 14b is a freezing evaporator (cooler) that absorbs heat in the freezing compartment 7 by exchanging heat between the refrigerant and the air in the freezing compartment 7. The R gas-liquid separator 54a and the F gas-liquid separator 54b are components that separate the gas refrigerant and the liquid refrigerant to prevent the liquid refrigerant from flowing into the compressor 24. The R gas-liquid separator 54a is provided downstream of the R evaporator 14a. The F gas-liquid separator 54b is provided downstream of the F evaporator 14b. The check valve 55 is a component that suppresses the backflow of the refrigerant. The check valve 55 is provided between the F gas-liquid separator 54b and the refrigerant junction 56. The refrigerant junction 56 is a portion where a refrigerant flow path FP4 and a refrigerant flow path FP5, which will be described later, join (connect).

[0038] The three-way valve 101 is a refrigerant control means for switching the direction of refrigerant flow between a cooling operation (refrigerating cooling operation and freezing cooling operation) and a defrosting operation. The three-way valve 101 flows the refrigerant to the heat dissipation means 50 side when performing the cooling operation (refrigerating cooling operation and freezing cooling operation), and flows the refrigerant to the defrosting pipe 102 side when performing the defrosting operation. Hereinafter, the "three-way valve 101" may be referred to as the "second refrigerant control means." The three-way valve 101 includes an outlet 101a connected to the external radiator 50a via a refrigerant piping, and an outlet 101b connected to the defrosting pipe 102, and can switch the outlet through which the refrigerant flows. The defrosting pipe 102 is a pipe through which a high-temperature refrigerant for heating the F evaporator 14b flows during a defrosting operation of the F evaporator 14b. The defrosting capillary tube 103 is a pressure reducing means for reducing the pressure of the refrigerant that has flowed through the defrosting pipe 102 . The check valve 104 is a component that suppresses the inflow of refrigerant into the defrosting pipe 102 during cooling operation. The check valve 104 is provided between the defrosting pipe 102 and the junction 105. The junction 105 is a portion where the refrigerant piping for the refrigeration / cooling operation (refrigerant flow path FP4) and the refrigerant piping for the defrosting operation (refrigerant flow path FP8) join (connect).

[0039] The refrigerator 1 has a refrigerant flow path FP so that the refrigerant flows between these components. In the example shown in Fig. 6A to Fig. 6C, the refrigerant flow path FP has refrigerant flow paths FP1 to FP8. However, the example shown in Fig. 6A to Fig. 6C is merely an example, and the refrigerant flow path FP may be divided (segmented) into a plurality of pipes or may be integrated into a plurality of pipes.

[0040] The refrigerant flow path FP1 is configured to connect the compressor 24 to the three-way valve 101. The refrigerant flow path FP2 is configured to connect the three-way valve 101 to the dew condensation prevention pipe 50c of the heat radiating means 50, passing through the external radiator 50a of the heat radiating means 50 and the wall surface heat radiating pipe 50b. 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 means 50 to the three-way valve 52. The refrigerant flow path FP4 is configured to pass through the R capillary tube 53a, the R evaporator 14a, and the R gas-liquid separator 54a, and connect the three-way valve 52 to the refrigerant junction 56. In the following description, the portion of the refrigerant flow path FP4 that connects the three-way valve 52 to the inlet In14a of the R evaporator 14a is referred to as the "refrigerant flow path FP4a." Also, the portion that connects the junction 105 to the refrigerant junction 56 is referred to as the "refrigerant flow path FP4b." The refrigerant flow path FP5 is configured to connect the three-way valve 52 to a refrigerant junction 56 through an F capillary tube 53b, an F evaporator 14b, an F gas-liquid separator 54b, and a check valve 55. The refrigerant flow path FP6 is configured to connect the refrigerant junction 56 to the compressor 24. The refrigerator 1 has an internal heat exchanger 58. The internal heat exchanger 58 is a heat exchanger that allows the R capillary tube 53a, the F capillary tube 53b, and the defrosting capillary tube 103 to exchange heat with the refrigerant flow path FP6 (a suction pipe 57 described later). The refrigerant flow path FP7 is configured to connect the three-way valve 101 to the defrosting pipe 102. The refrigerant flow path FP8 is configured to connect the defrost pipe 102 to the junction 105 through the defrost capillary tube 103 and the check valve 104. The order of the defrost capillary tube 103 and the check valve 104 may be reversed.

[0041] The three-way valve 52 is a member that has two outlets 52a and 52b and can switch the direction of refrigerant flow. The three-way valve 52 can be in a fully closed state in which the refrigerant does not flow through both the outlets 52a and 52b. The three-way valve 52 can also be in a double-open state in which the refrigerant flows through both the outlets 52a and 52b. The outlet 52a of the three-way valve 52 is connected to the R capillary tube 53a via a refrigerant pipe. On the other hand, the outlet 52b of the three-way valve 52 is connected to the F capillary tube 53b via a refrigerant pipe.

[0042] In this embodiment, of the refrigerant piping FP, the refrigerant return piping (refrigerant flow path FP6) that returns the refrigerant from the R evaporator 14a and the F evaporator 14b to the compressor 24 is referred to as a "suction pipe 57." Also, as shown in Fig. 4A, the refrigerant piping that connects the outlet of the F capillary tube 53b (Fig. 5) through the F evaporator 14b to the F gas-liquid separator 54b (piping with a part connected to the F evaporator 14b) is referred to as an F evaporator refrigerant piping 59.

[0043] The suction pipe 57 (refrigerant flow path FP6) can exchange heat with part or all of the R capillary tube 53a, part or all of the F capillary tube 53b, and part or all of the defrosting capillary tube 103 in the internal heat exchange section 58.

[0044] The internal heat exchanger 58 may be configured such that the R capillary tube 53a, the F capillary tube 53b, and the defrosting capillary tube 103 are close to the suction pipe 57 (refrigerant flow path FP6) to exchange heat. In the refrigerator 1 of the first embodiment, the R capillary tube 53a, the F capillary tube 53b, and the defrosting capillary tube 103 are soldered to the suction pipe 57 (refrigerant flow path FP6). The refrigerator 1 has improved heat exchange efficiency by being fixedly connected by a metal member through soldering.

[0045] 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.

[0046] In this embodiment, the defrosting pipe 102 is connected via a refrigerant piping to the outlet 101b and one end of the defrosting capillary tube 103. The other end of the defrosting capillary tube 103 is connected via a refrigerant piping to the inlet side of the check valve 104. The outlet side of the check valve 104, which is the outlet of the refrigerant piping for the defrosting operation, is connected to the above-mentioned junction 105 via a refrigerant piping.

[0047] The three-way valve 101, like the three-way valve 52, is a member that has two outlets 101a, 101b and can switch the direction of refrigerant flow. The outlet 101a of the three-way valve 101 is connected to the external radiator 50a via a refrigerant piping. On the other hand, the outlet 101b of the three-way valve 101 is connected to a defrosting pipe 102 via a refrigerant piping. The outlet Out102 of the defrosting pipe 102 is the outlet of the portion that exchanges heat with the F evaporator 14b (evaporator for refrigeration) during defrosting operation.

[0048] For reasons that will be described later, the flow resistance (magnitude of pressure loss under the same conditions) of the defrosting capillary tube 103 is set lower (smaller) than the flow resistance of the R capillary tube 53a. In other words, the flow resistance from the defrosting pipe 102 to the R evaporator 14a is set lower (smaller) than the flow resistance from the three-way valve 52 to the R evaporator 14a.

[0049] Fig. 6A, Fig. 6B, and Fig. 6C are explanatory diagrams showing the flow of refrigerant in the refrigerator 1 of the first embodiment. Specifically, Fig. 6A shows the refrigerant flow during refrigeration cooling operation (R cooling operation) in which the refrigerant is caused to flow through the R evaporator 14a to cool the refrigerator compartment 2 (Fig. 1). Fig. 6B shows the refrigerant flow during freezing cooling operation (F cooling operation) in which the refrigerant is caused to flow through the F evaporator 14b to cool the freezer compartment 7 (Fig. 1) and the like. Fig. 6C shows the refrigerant flow during defrosting operation in which the F evaporator 14b is defrosted.

[0050] First, the flow of the refrigerant during the refrigeration and cooling operation will be described with reference to Fig. 6A. As shown in Fig. 6A, during the refrigeration and cooling operation, the refrigerant discharged from the compressor 24 flows through the refrigerant flow paths FP1, FP2, FP3, FP4, and FP6 and returns to the compressor 24.

[0051] As shown in FIG. 6A, in the refrigeration / cooling operation, the refrigerator 1 opens the three-way valve 101 to the outlet 101a on the heat dissipation means 50 (external radiator 50a) side. In the refrigerator 1, when the compressor 24 is driven, the refrigerant is compressed to become a high-temperature, high-pressure gas refrigerant. After passing through the three-way valve 101, the high-temperature, high-pressure gas refrigerant flows through the external radiator 50a, the wall surface heat dissipation piping 50b, and the condensation prevention piping 50c to dissipate heat and become a liquid refrigerant. Thereafter, the refrigerant flows through the dryer 51 to remove moisture, and then reaches the three-way valve 52.

[0052] Then, the refrigerator 1 opens the three-way valve 52 to the outlet 52a side so that the refrigerant flows to the outlet 52a side. The refrigerant flowing out from the outlet 52a is decompressed by the R capillary tube 53a, becomes a low-temperature, low-pressure, two-phase gas-liquid refrigerant, and reaches the inlet of the R evaporator 14a through the junction 105. In the refrigerator 1, air flows from the refrigerator compartment 2 (FIG. 2) into the R evaporator chamber 8a by driving the R fan 9a. The air that flows into the R evaporator chamber 8a exchanges heat with the low-temperature refrigerant in the R evaporator 14a while passing through the R evaporator 14a, becomes low in temperature, and is sent out again to the refrigerator compartment 2 (FIG. 2). At this time, the refrigerant absorbs heat from the air inside the refrigerator (inside the refrigerator compartment 2 (FIG. 2)), increases its enthalpy, increases its dryness, and becomes a substantially saturated gas refrigerant. The refrigerant then reaches the outlet of the R evaporator 14a, passes through the R gas-liquid separator 54a, and reaches the suction pipe 57. The suction pipe 57 constitutes a refrigerant flow path FP6, and is connected to the compressor 24. The refrigerant flows through the suction pipe 57 (refrigerant flow path FP6) and returns to the compressor 24.

[0053] Next, the flow of the refrigerant during the freezing and cooling operation will be described with reference to Fig. 6B. As shown in Fig. 6B, during the freezing and cooling operation, the refrigerant discharged from the compressor 24 flows through the refrigerant flow paths FP1, FP2, FP3, FP5, and FP6 and returns to the compressor 24.

[0054] As shown in FIG. 6B, in the freezing and cooling operation, the refrigerator 1 opens the three-way valve 101 to the outlet 101a on the heat dissipation means 50 (external radiator 50a) side, as in the refrigerating and cooling operation. In the refrigerator 1, when the compressor 24 is driven, the refrigerant is compressed to become a high-temperature, high-pressure gas refrigerant. After passing through the three-way valve 101, the high-temperature, high-pressure gas refrigerant flows through the external radiator 50a, the wall surface heat dissipation piping 50b, and the condensation prevention piping 50c to dissipate heat and become a liquid refrigerant. Thereafter, the refrigerant flows through the dryer 51 to remove moisture, and then reaches the three-way valve 52.

[0055] The refrigerator 1 opens the three-way valve 52 to the outlet 52b side so that the refrigerant flows to the outlet 52b side, unlike during refrigeration / cooling operation. The refrigerant flowing out from the outlet 52b is decompressed by the F capillary tube 53b, becomes a low-temperature, low-pressure, gas-liquid two-phase refrigerant, and then reaches the inlet of the F evaporator 14b. In the refrigerator 1, air flows into the F evaporator chamber 8b from the freezer chamber 7 (FIG. 2) and the vegetable chamber 6 (FIG. 2) by driving the F fan 9b. The air that flows into the F evaporator chamber 8b exchanges heat with the low-temperature refrigerant in the F evaporator 14b when passing through the F evaporator 14b, becomes low in temperature, and is sent out again to the freezer chamber 7 (FIG. 2) and the vegetable chamber 6 (FIG. 2). At this time, the refrigerant absorbs heat from the air inside the refrigerator (in the freezer chamber 7 (FIG. 2) and the vegetable chamber 6 (FIG. 2)), increases its enthalpy, increases its dryness, and becomes a substantially saturated gas refrigerant. The refrigerant then reaches the outlet of the F evaporator 14b, passes through the F gas-liquid separator 54b and the check valve 55, and reaches the suction pipe 57 (refrigerant flow path FP6). The suction pipe 57 has a refrigerant junction 56 where the downstream side of the R gas-liquid separator 54a and the downstream side of the F gas-liquid separator 54b join (connect), and is configured to connect the refrigerant junction 56 to the compressor 24. The refrigerant flows through the suction pipe 57 (refrigerant flow path FP6) and returns to the compressor 24.

[0056] 6A and 6B, the refrigerant returns to the compressor 24 via the suction pipe 57 (refrigerant flow path FP6). At that time, the suction pipe 57 (refrigerant flow path FP6) is configured to exchange heat with the R capillary tube 53a and the F capillary tube 53b in the internal heat exchanger 58. Therefore, the refrigerant passing through the suction pipe 57 is heated by the refrigerant in the R capillary tube 53a or the F capillary tube 53b, and the enthalpy increases (the temperature increases) before returning to the compressor 24.

[0057] By providing the internal heat exchanger 58, the refrigerator 1 can increase the temperature of the refrigerant sucked into the compressor 24. Therefore, the refrigerator 1 can prevent condensation and frost from forming on the suction pipe 57 because the refrigerant temperature in the suction pipe 57 (FIG. 3) in the machine room 39 (FIG. 3) in which the compressor 24 is provided is high. Also, the refrigerator 1 can reduce the enthalpy of the refrigerant flowing into the R evaporator 14a and the F evaporator 14b by heat exchange. Therefore, the refrigerator 1 can improve the cooling capacity of the R evaporator 14a and the F evaporator 14b. Also, in the refrigerator 1 using a refrigerant such as isobutane, by providing the internal heat exchanger 58, the cooling efficiency (the ratio of the amount of heat to be cooled to the input of the compressor 24), that is, the energy saving performance can be improved due to the relationship between the ratio of the improvement in the cooling capacity by providing the internal heat exchanger 58 and the increase in the compression power of the compressor 24.

[0058] Next, the flow of the refrigerant during the defrosting operation will be described with reference to Fig. 6C. As shown in Fig. 6C, during the defrosting operation, the refrigerant discharged from the compressor 24 flows through the refrigerant flow paths FP1, FP7, FP8, FP4b, and FP6, and returns to the compressor 24. The refrigerant flow path FP4b is a portion of the refrigerant flow path FP4 that connects the junction 105 to the refrigerant junction 56.

[0059] As shown in FIG. 6C, in the defrosting operation, the refrigerator 1 opens the three-way valve 101 to the outlet 101b on the defrosting pipe 102 side. In the refrigerator 1, when the 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 the three-way valve 101, flows through the defrosting pipe 102, and exchanges heat with the F evaporator 14b. As a result, the refrigerator 1 causes the gas refrigerant in the defrosting pipe 102 to radiate heat and heat the F evaporator 14b. Due to this heat radiation, the temperature of the gas refrigerant drops and the gas refrigerant liquefies. The liquefied refrigerant passes through the defrosting capillary tube 103. At this time, the refrigerant is decompressed by the defrosting capillary tube 103 and becomes a low-temperature, low-pressure two-phase gas-liquid refrigerant. The low-temperature, low-pressure refrigerant passes through the check valve 104, and then reaches the inlet of the R evaporator 14a via the junction 105. The low-temperature R evaporator 14a exchanges heat with the surrounding air. This reduces the temperature of the surrounding air. The low-temperature surrounding air is sent to the refrigerator compartment 2 (FIG. 1) by the R fan 9a. This cools the refrigerator compartment 2 of the refrigerator 1. This heat exchange causes the refrigerant in the R evaporator 14a to absorb heat from the air inside the refrigerator (inside the refrigerator compartment 2 (FIG. 1)), increasing its enthalpy and dryness, and becoming a substantially saturated gas refrigerant. The refrigerant then reaches the outlet of the R evaporator 14a, passes through the R gas-liquid separator 54a, and reaches the suction pipe 57 (refrigerant flow path FP6). The refrigerant then flows through the suction pipe 57 (refrigerant flow path FP6) and returns to the compressor 24.

[0060] The flow of the refrigerant from the junction 105 to the compressor 24 during the defrosting operation is the same as that during the refrigeration / cooling operation (FIG. 6A). However, during the defrosting operation, the refrigerant in the suction pipe 57 (refrigerant flow path FP6) mainly exchanges heat with the refrigerant in the defrosting capillary tube 103 via the internal heat exchanger 58.

[0061] The flow resistance R103 (FIG. 6C) of the defrosting capillary tube 103 is set lower than the flow resistance R53a of the R capillary tube 53a (refrigeration pressure reducing means). The flow resistance R1 (FIG. 6C) of the refrigerant path FP8 connecting the outlet Out102 of the defrosting pipe 102 to the inlet In14a of the R evaporator 14a is set lower than the flow resistance R2 (FIG. 6C) of the refrigerant paths FP3 and FP4a connecting the outlet Out50 of the heat dissipation means 50 to the inlet In14a of the R evaporator 14a. The refrigerant path FP4a is a portion of the refrigerant path FP4 that connects the three-way valve 52 to the inlet In14a of the R evaporator 14a.

[0062] 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 indicates pressure P, and the horizontal axis indicates specific enthalpy h. Note that FIG. 7 shows a theoretical cycle in which various losses are ignored. Also, the difference Δq between the two enthalpies shown in FIG. 7 is the same value (equal). Also, the amount of heat q and the amount of power consumption wa shown in FIG. 7 are the energy of the refrigerant per 1 kg, but a description of the refrigerant per 1 kg will be omitted.

[0063] In Figure 7, state C 1 indicates the state of the inlet of the compressor 24. Also, state C 2 indicates the state of the outlet of the compressor 24. Also, state C 3 shows the state of the inlet of the defrosting capillary tube 103. Also, state C 4 shows the state of the outlet of the defrosting capillary tube 103. Also, state C 5 shows the state of the outlet of the F evaporator 14b.

[0064] Condition C 1 The refrigerant is compressed by the compressor 24 to a condensation pressure P d Condition C 2 The power consumption of the compressor 24 at this time is wa. State C 2 The refrigerant of F evaporator 14b releases heat q H After 10 minutes of heat dissipation, it reaches state C. 3 State C 3As the refrigerant passes through the defrosting capillary tube 103, the pressure of the refrigerant is increased to a condensation pressure P d From evaporation pressure P s In addition, in state C 3 The refrigerant in the internal heat exchange section 58 has a specific enthalpy of C 3 Q of time 3 and condition C 4 Q of time 4 The difference between the two, Δq, decreases to state C. 4 Then, in state C 4 The refrigerant absorbs heat q by heat exchange with the R evaporator 14a. c Heat is absorbed and the state changes to C 5 State C 5 The refrigerant in state C returns to the compressor 24 through the suction pipe 57. 5 The refrigerant in the internal heat exchange section 58 has a specific enthalpy of C 1 Q of time 1 and condition C 5 Q of time 5 The difference between the two increases by Δq to state C 1 That is, state C 5 The refrigerant returns to the state at the inlet of the compressor 24 by passing through the suction pipe 57.

[0065] Here, the difference Δq between the two enthalpies shown in FIG. 7 is the same value (equal). From this, state C 1 and condition C 3 The difference in specific enthalpy between (q 1 -q 3 ) is the amount of heat absorbed q c Also, as can be seen from Figure 7, the heat dissipation q H is "q H =(wa+(q 1 -q 3 ))=(wa+q c Therefore, in the theoretical cycle, the amount of heat radiation q used to heat the F evaporator 14b is H is the power consumption of the compressor 24 wa and the heat absorption amount of the evaporator 14a q c The combined value (wa+q cTherefore, the refrigerator 1 has a heat radiation amount q that is greater than the power consumption amount wa of the compressor 24. H (amount of heat) can be obtained. The above are the basic specifications of the refrigerator 1 of the first embodiment.

[0066] <Effect of defrosting structure of refrigerator 1> Hereinafter, the effect of the defrosting structure of the refrigerator 1 of the first embodiment realized by the refrigeration cycle shown in Fig. 6C will be described. The defrosting structure of the refrigerator 1 of the first embodiment has higher energy saving performance than the defrosting structure using an electric heater for the following reasons.

[0067] (Reason 1) In a defrosting structure using a general electric heater, the amount of heat generated by the heater used to heat the evaporator is equal to the amount of power consumed. In contrast, in the defrosting structure of the refrigerator 1 of the first embodiment, as shown in FIG. 7, the amount of heat dissipation q used to heat the F evaporator 14b is equal to the amount of power consumed. H The amount of heat radiation q is greater than the power consumption wa of the compressor 24. H (amount of heat) can be obtained. In addition, in a defrosting structure using an electric heater that heats the F evaporator 14b through radiation such as a radiant heater or air convection, much of the heat generation is used to heat the surrounding wall surface. Therefore, the amount of heat to the F evaporator 14b is small relative to the amount of heat generation. In contrast, in the defrosting structure of the refrigerator 1 of the first embodiment, the refrigerant in the defrosting pipe 102, which is the heat source, directly exchanges heat with the F evaporator 14b. Therefore, the refrigerator 1 can reduce the loss of heat. The defrosting structure of the refrigerator 1 of the first embodiment has a defrosting operation with higher heating efficiency than a defrosting structure that uses an electric heater.

[0068] (Reason 2) Furthermore, in the defrosting structure of the refrigerator 1 of the first embodiment, the amount of heat absorbed from the refrigerating chamber 2 through the R evaporator 14a during the defrosting operation is q c Therefore, the defrosting structure of the refrigerator 1 of the first embodiment can reduce the heat load on the refrigeration compartment 2 by performing the defrosting operation of Fig. 6C, and can reduce the power consumption of the compressor 24 by performing the refrigeration cooling operation of Fig. 6A. For these reasons, the defrosting structure of the refrigerator 1 of the first embodiment is a defrosting structure with high energy-saving performance.

[0069] <Effect of heat dissipation bypass and independent capillary tube> The refrigerator 1 of the first embodiment is provided with a defrosting pipe 102 as an independent refrigerant pipe in contact with the F evaporator 14b for heat exchange with the F evaporator 14b. The refrigerator 1 of the first embodiment is also provided with a defrosting capillary tube 103 as an independent capillary tube. The refrigerator 1 of the first embodiment is provided with features to be described later so that the defrosting time can be shortened and defrosting can be performed with higher heating efficiency in the defrosting operation.

[0070] In order to easily explain the effect of the refrigeration cycle of the refrigerator 1 of the first embodiment, a configuration of a refrigerator 1001 having a refrigeration cycle of a first comparative example and a configuration of a refrigerator 1002 having a refrigeration cycle of a second comparative example will be described below with reference to Figs. 8 and 9. Then, a state during a defrosting operation of the refrigeration cycle of the first embodiment, the refrigeration cycle of the first comparative example, and the refrigeration cycle of the second comparative example will be described with reference to Fig. 10. Fig. 8 is a schematic diagram showing the refrigeration cycle (refrigerant flow path) of the first comparative example. Fig. 9 is a schematic diagram showing the refrigeration cycle (refrigerant flow path) of the second comparative example. Fig. 10 is a Ph diagram showing a state during a defrosting operation of the refrigeration cycle of the first embodiment, the refrigeration cycle of the first comparative example, and the refrigeration cycle of the second comparative example. The refrigeration cycle of the first comparative example and the refrigeration cycle of the second comparative example are refrigeration cycles virtually designed based on the refrigeration cycle of the first embodiment (Fig. 5).

[0071] As shown in FIG. 8, the refrigeration cycle of the first comparative example is different from the refrigeration cycle of the first embodiment (FIG. 5) in that the three-way valve 101 (FIG. 5) is not provided immediately after the compressor 24, but a three-way valve 201 is provided between the outlet of the wall surface heat dissipation pipe 50b and the inlet of the condensation prevention pipe 50c. The three-way valve 201 is a refrigerant control means that switches the direction of the refrigerant flow between the cooling operation (refrigeration cooling operation and freezing cooling operation) and the defrosting operation, similar to the three-way valve 101 (FIG. 5). The three-way valve 201 flows the refrigerant to the condensation prevention pipe 50c side when performing the cooling operation (refrigeration cooling operation and freezing cooling operation), and flows the refrigerant to the defrosting pipe 102 side when performing the defrosting operation. The refrigeration cycle of the first comparative example is configured such that the refrigerant discharged from the compressor 24 passes through some of the heat dissipation means (external radiator 50a and wall surface heat dissipation pipe 50b) before being sent to the defrosting pipe 102.

[0072] Moreover, the refrigeration cycle of the first comparative example differs from the refrigeration cycle of the first embodiment (FIG. 5) in that it has a defrosting capillary tube 203 instead of the defrosting capillary tube 103 (FIG. 5). The defrosting capillary tube 203 is a capillary tube having a flow path resistance similar to that of the R capillary tube 53a.

[0073] Furthermore, compared to the refrigeration cycle of the first comparative example (FIG. 5), the refrigeration cycle of the first comparative example is configured to include refrigerant flow paths FP11 to FP18 instead of the refrigerant flow paths FP1 to FP8.

[0074] The refrigerant flow path FP11 is configured to connect the compressor 24 to the three-way valve 101. The refrigerant flow path FP12 is configured to connect the three-way valve 101 to the three-way valve 201 through the external radiator 50a of the heat radiating means 50 and the wall surface heat radiation piping 50b. The refrigerant flow path FP13 is configured to pass through the dew condensation prevention pipe 50c of the heat dissipation means 50 and connect the three-way valve 201 to the three-way valve 52. The refrigerant flow path FP14 is configured to connect from the three-way valve 52 to the refrigerant junction 56 through the R capillary tube 53a, the R evaporator 14a, and the R gas-liquid separator 54a. The refrigerant flow path FP15 is configured to connect the three-way valve 52 to the refrigerant junction 56 through the F capillary tube 53b, the F evaporator 14b, the F gas-liquid separator 54b, and the check valve 55. The refrigerant flow path FP16 is configured to connect the refrigerant junction 56 to the compressor 24. The refrigerant flow path FP17 is configured to connect the three-way valve 201 to the defrosting pipe 102. The refrigerant flow path FP18 is configured to connect the defrosting pipe 102 to the junction 105 through the defrosting capillary tube 103 and the check valve 104.

[0075] Other parts of the refrigeration cycle of the first comparative example are the same as those of the refrigeration cycle of the first embodiment (FIG. 5).

[0076] On the other hand, as shown in FIG. 9, the refrigerator of the second comparative example differs from the refrigeration cycle of the first embodiment (FIG. 5) in that it is equipped with a check valve 204 and refrigerant flow paths FP21-FP28 instead of the defrosting capillary tube 103, the check valve 104, and the refrigerant flow paths FP1-FP8.

[0077] The refrigerant flow path FP21 is configured to connect the compressor 24 to the three-way valve 101. The refrigerant flow path FP22 is configured to connect the three-way valve 101 to the dew condensation prevention pipe 50c of the heat radiating means 50, passing through the external radiator 50a of the heat radiating means 50 and the wall surface heat radiating pipe 50b. 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 means 50 to the three-way valve 52. The refrigerant flow path FP24 is configured to connect the three-way valve 52 to the refrigerant junction 56 through the R capillary tube 53a, the R evaporator 14a, and the R gas-liquid separator 54a. The refrigerant flow path FP25 is configured to connect the three-way valve 52 to the refrigerant junction 56 through the F capillary tube 53b, the F evaporator 14b, the F gas-liquid separator 54b, and the check valve 55. The refrigerant flow path FP26 is configured to connect the refrigerant junction 56 to the compressor 24. The refrigerant flow path FP27 is configured to connect the three-way valve 101 to the defrosting pipe 102. The refrigerant flow path FP28 is configured to connect the defrosting pipe 102 to the junction 106 through the check valve 204. The junction 106 is a portion where the refrigerant piping for the cooling operation (refrigerant flow path FP22) and the refrigerant piping for the defrosting operation (refrigerant flow path FP28) join (connect).

[0078] Such a refrigeration cycle of the second comparative example is configured such that the refrigerant that has passed through the defrosting pipe 102 flows upstream of the dryer 51 and the three-way valve 52. That is, the refrigeration cycle of the second comparative example is configured such that during defrosting operation, the refrigerant is made to pass through the R capillary tube 53a and then to flow into the R evaporator 14a (refrigerating cooler). Other parts of the refrigeration cycle of the second comparative example are the same as those of the refrigeration cycle of the first embodiment (FIG. 5).

[0079] Hereinafter, the states during defrosting operation of the refrigeration cycle of the first embodiment (FIG. 5), the refrigeration cycle of the first comparative example (FIG. 8), and the refrigeration cycle of the second comparative example (FIG. 9) will be described with reference to Fig. 10. Note that the description here assumes that the outside air temperature is sufficiently higher (for example, 20°C or higher) than the melting point of frost (0°C).

[0080] In addition, among the various parameters shown in Fig. 10, the parameters with a "1" suffix to the reference numerals correspond to the refrigeration cycle of the first comparative example (Fig. 8). The parameters with a "2" suffix to the reference numerals correspond to the refrigeration cycle of the second comparative example (Fig. 9). The parameters with a "3" suffix to the reference numerals correspond to the refrigeration cycle of the first embodiment (Fig. 5).

[0081] First, the heating efficiency of each refrigeration cycle will be described by comparing the refrigeration cycle of the first comparative example (FIG. 8), the refrigeration cycle of the second comparative example (FIG. 9), and the refrigeration cycle of the first embodiment (FIG. 5). In the refrigeration cycle of the first comparative example (FIG. 8), heat is radiated through the external radiator 50a and the wall surface heat radiation pipe 50b during defrosting operation. Therefore, in the refrigeration cycle of the first comparative example, the condensation temperature of the refrigerant during defrosting operation is equal to or higher than the outside air temperature, and is close to the value during normal cooling operation. Also, the refrigerant is depressurized by the defrosting capillary tube 203, which has a flow resistance similar to that of the R capillary tube 53a. Therefore, in the refrigeration cycle of the first comparative example, the condensation pressure P d1 and evaporation pressure P s1 Both values ​​are relatively close to those during normal cooling operation.

[0082] On the other hand, the refrigeration cycle of the second comparative example (FIG. 9) exchanges heat between the refrigerant and the F evaporator 14b (refrigeration cooler) on which frost is formed, which is much lower in temperature than the outside of the refrigerator, during defrosting operation. Therefore, in the refrigeration cycle of the second comparative example, the condensation temperature of the refrigerant during defrosting operation is likely to be low. In such a refrigeration cycle of the second comparative example, the condensation pressure P d2 In the refrigeration cycle of the second comparative example, the condensation pressure P d2 The pressure is reduced from a low level by the capillary tube 53a in the same manner as in the cooling operation. Therefore, in the refrigeration cycle of the second comparative example, the evaporation pressure P s2 It is also easy for the temperature to become low.

[0083] In contrast, the refrigeration cycle of the first embodiment (FIG. 5) exchanges heat between the refrigerant and the F evaporator 14b (refrigeration cooler) like the refrigeration cycle of the second comparative example (FIG. 9). Therefore, in the refrigeration cycle of the first embodiment, the condensation temperature of the refrigerant during defrosting operation tends to be low. In such a refrigeration cycle of the first embodiment, the condensation pressure P d3 Here, the refrigeration cycle of the first embodiment has a condensation pressure P d3The defrosting capillary tube 103 has a lower flow resistance than the F capillary tube 53b, but the pressure is reduced by using the defrosting capillary tube 103. Therefore, in the refrigeration cycle of the first embodiment, the evaporation pressure P s3 is the evaporation pressure P of the refrigerant during defrosting operation of the refrigeration cycle of the second comparative example (FIG. 9). s2 In the refrigeration cycle of the first embodiment, the condensation pressure P d3 can be made relatively low, and the evaporation pressure P s3 can be made relatively high, and the evaporation pressure P s and condensation pressure P d The difference can be reduced.

[0084] Generally, the evaporation pressure P s and condensation pressure P d When the difference between these is large, the power consumption wa of the compressor 24 per kg of the refrigerant becomes large. Therefore, as can be seen from Fig. 10, the power consumption wa of the compressor 24 per kg of the refrigerant is the smallest in the power consumption w3 of the refrigeration cycle of the first embodiment (Fig. 5).

[0085] In the refrigeration cycle of the first comparative example (FIG. 8), the refrigerant that has radiated heat in the external radiator 50a and the wall surface heat radiation pipe 50b reaches the defrosting pipe 102. Here, the state of the inlet of the defrosting pipe 102 is referred to as state C. 61 The amount of heat radiated by the external radiator 50a and the wall surface heat radiation pipe 50b is the amount of heat radiated q LOSS1 (loss amount). Then, this heat dissipation amount q LOSS1 Therefore, state C 61 is the state C of the inlet of the defrosting pipe 102 of the refrigeration cycle of the first embodiment (FIG. 5). 2 In addition, the specific enthalpy is likely to be smaller than that in the first comparative example (FIG. 8) in which the condensation pressure is high. 31 The specific enthalpy at the outlet of the defrosting pipe 102 in the refrigeration cycle of the first embodiment (FIG. 5) is 33 Therefore, the refrigeration cycle of the first embodiment (Fig. 5) has a specific enthalpy of q LOSS1 The amount of heat dissipated by the defrosting pipe 102 qH1 can be reduced.

[0086] In the refrigeration cycle of the second comparative example (FIG. 9), the pressure rise in the compressor 24 is relatively large. Therefore, in the state C of the outlet of the compressor 24 and the inlet of the defrosting pipe 102 in the refrigeration cycle of the second comparative example (FIG. 9), 22 The specific enthalpy at the inlet state C of the refrigeration cycle of the first embodiment (FIG. 5) is 22 In addition, the specific enthalpy q of the defrosting pipe 102 in the refrigeration cycle of the second comparative example (FIG. 9) is larger than that in the H2 The heat radiation amount q of the defrosting pipe 102 in the refrigeration cycle of the first embodiment (FIG. 5) H3 However, the amount of heat released per kg of refrigerant, q H2 andq H3 The difference is relatively small.

[0087] In the first comparative example, the second comparative example, and the first embodiment, the amount of heat radiation q H (heat amount) is compared, "q H2 ≒q H3 >q H1 Therefore, when comparing the power consumption wa consumed by the compressor 24, "w1 ≒ w2 > w3" holds. In addition, the heating efficiency (the amount of heat released by the defrosting pipe 102 with respect to the power consumption wa consumed by the compressor 24) is H The amount of heat (heating power) is the highest in the refrigeration cycle of the first embodiment (FIG. 5). The refrigerator 1 equipped with the refrigeration cycle of the first embodiment (FIG. 5) can perform defrosting with higher heating efficiency than the refrigerator 1001 equipped with the refrigeration cycle of the first comparative example (FIG. 8) and the refrigerator 1002 equipped with the refrigeration cycle of the second comparative example (FIG. 9).

[0088] Next, the heat dissipation amount q of the defrosting pipe 102 H The amount of heat (heating amount) will be described by comparing the refrigeration cycle of the first comparative example (FIG. 8), the refrigeration cycle of the second comparative example (FIG. 9), and the refrigeration cycle of the first embodiment (FIG. 5). H (heat amount) is a parameter that affects the defrosting time. The heat dissipation amount q of the defrosting pipe 102 HThe greater the amount of heat, the shorter the defrosting time can be.

[0089] During the defrosting time, freezing and cooling by the F evaporator 14b cannot be performed. Therefore, by shortening the defrosting time, the refrigerator 1 can reduce the time during which freezing and cooling by the F evaporator 14b cannot be performed, and can suppress temperature fluctuations in the storage compartment.

[0090] Here, the amount of heat dissipated by the defrosting pipe 102, q H As described above, the (heating amount) and the power consumption wa consumed by the compressor 24 are, precisely, the heating amount and power consumption of the refrigerant per 1 kg, and are expressed in units of [J / kg]. On the other hand, the actual heating amount per unit time, expressed in units of [W], and the power consumption of the compressor 24 depend on the amount of refrigerant circulating. Specifically, if the amount of refrigerant circulating per second [kg / s] is G, then the actual amount of heat radiation Q of the defrosting pipe 102 taking into account the amount of refrigerant circulating G is H "Q H =q H × G", and the actual power consumption W A24 "W A24 =wa×G".

[0091] Here, assuming that the volumetric efficiency is constant, the refrigerant circulation amount G is determined mainly by the displacement amount and rotation speed of the piston of the compressor 24, and the density of the refrigerant flowing into the compressor 24. The density of the refrigerant flowing into the compressor 24 is determined mainly by the pressure and temperature of the refrigerant flowing into the compressor 24. Note that since the refrigerant flowing into the compressor 24 is a gas refrigerant, as the refrigerant pressure increases, the refrigerant density increases, and conversely, as the refrigerant temperature increases, the refrigerant density decreases.

[0092] Here, assuming that there is no pressure loss other than in the capillary tube, the pressure of the refrigerant flowing into the compressor 24 is the evaporation pressure P s Evaporation pressure P s As described above, the evaporation pressure P s3 In comparison, the evaporation pressure P s2is lower. On the other hand, it is considered that there is no significant difference in the refrigerant temperature. Therefore, when the piston displacement and rotation speed of the compressor 24 are the same, the refrigerant circulation amount G2 in the refrigeration cycle of the second comparative example (FIG. 9) is smaller than the refrigerant circulation amount G3 in the refrigeration cycle of the first embodiment (FIG. 5). H2 ≒q H3 " Therefore, the actual heat dissipation amount Q of the defrosting pipe 102 taking into account the refrigerant circulation amount G is H "Q H3 >Q H2 ". In the refrigeration cycle of the first comparative example (Fig. 8), the refrigeration cycle of the second comparative example (Fig. 9), and the refrigeration cycle of the first embodiment (Fig. 5), the state of the refrigerant flowing into the compressor 24 is equivalent. In the refrigeration cycle of the first comparative example (Fig. 8), the refrigeration cycle of the second comparative example (Fig. 9), and the refrigeration cycle of the first embodiment (Fig. 5), the refrigerant circulation amount G (i.e., refrigerant circulation amounts G1, G3) are also equivalent. In addition, the amount of heat radiation q H (heat amount) is, as mentioned above, "q H3 >q H1 Therefore, the actual heat dissipation amount Q of the defrosting pipe 102 is H Also "Q H3 >Q H1 "

[0093] Thus, the refrigeration cycle of the first embodiment (FIG. 5) has a smaller heat radiation amount Q of the defrosting pipe 102 that heats the F evaporator 14b than the refrigeration cycle of the first comparative example (FIG. 8) and the refrigeration cycle of the second comparative example (FIG. 9). H Therefore, the refrigeration cycle of the first embodiment (FIG. 5) can shorten the defrosting time during the defrosting operation.

[0094] In the refrigeration cycle of the first embodiment (FIG. 5), a defrosting capillary tube 103 (thin tube) is used to generate a pressure difference between the heat radiation side and the heat absorption side. However, frost can be melted as long as the temperature on the heat radiation 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 the refrigerator compartment 2 (approximately 4°C on average, approximately 10°C at high temperatures). Therefore, a large pressure difference is not necessary. Therefore, if the condensation temperature can be sufficiently lowered, the refrigeration cycle of the first embodiment (FIG. 5) may be configured so that there is almost no pressure difference between the heat radiation side and the heat absorption side, with only the pressure loss generated in the refrigerant piping, without using the defrosting capillary tube 103 such as a thin tube.

[0095] Moreover, the refrigeration cycle of the first embodiment (FIG. 5) differs from the refrigeration cycle of the first comparative example (FIG. 8) in that the heat dissipation means 50 (particularly the external radiator 50a and the wall surface heat dissipation pipe 50b) is bypassed during defrosting operation. As a result, the refrigeration cycle of the first embodiment (FIG. 5) suppresses heat dissipation from the compressor 24 to the defrost pipe 102, suppresses heat dissipation to the outside of the refrigerator, and improves the specific enthalpy at the time of inflow into the defrost pipe 102. The refrigeration cycle of the first embodiment (FIG. 5) has a heat dissipation amount q H Since the reduction in the amount of heat (heat) can be suppressed, the heating efficiency can be improved. However, the refrigeration cycle of the first embodiment (FIG. 5) does not necessarily have to suppress all heat radiation except from the defrosting pipe 102. The refrigeration cycle of the first embodiment (FIG. 5) is provided with a three-way valve 101 for switching between cooling operation and defrosting operation between the compressor 24 and before the inflow of the urethane foam having the wall surface heat radiation pipe 50b. Generally, heat radiation in a refrigerator is dominated by the wall surface heat radiation pipe 50b, so that the refrigerant is caused to flow so as to bypass the wall surface heat radiation pipe 50b, and therefore the refrigeration cycle of the first embodiment (FIG. 5) can efficiently suppress heat radiation between the compressor 24 and the defrosting pipe 102.

[0096] Furthermore, for example, in the refrigeration cycle of the first embodiment (FIG. 5), by providing three-way valve 101 in machine chamber 39 rather than in the urethane foam, it is possible to improve ease of manufacture and ease of replacement in the event of a malfunction.

[0097] <Effect of the internal heat exchange section 58> The refrigerator 1 of the first embodiment has an internal heat exchanger 58. As a result, the refrigerator 1 of the first embodiment can increase the temperature of the refrigerant sucked into the compressor 24, and can prevent dew condensation or frost from forming on the suction pipe 57 (FIG. 3) in the machine room 39.

[0098] As can be seen from FIG. 7, the refrigerator 1 of the first embodiment has a refrigerant (state C 1 ) can be increased by the difference Δq. As a result, the refrigerator 1 of the first embodiment can increase the enthalpy of the refrigerant in the state C 2 This can increase the enthalpy of the refrigerant in the refrigerator 1 of the first embodiment. This can increase the amount of heat released (amount of heat) from the refrigerant used to heat the F evaporator 14b (refrigeration cooler).

[0099] In addition, the refrigerator 1 of the first embodiment can improve the heating efficiency (the ratio of the amount of heat in the F evaporator 14b to the amount of power consumption) of a refrigerant such as isobutane, due to the relationship between the ratio of the increase in the amount of heat radiation (amount of heat) and the increase in the compression power of the compressor 24, that is, can improve the energy saving performance.

[0100] Furthermore, the refrigerator 1 of the first embodiment absorbs heat in the refrigerator compartment 2 with a heat quantity q even during defrosting operation. c The cooling amount is q c Even if the temperature is low, Δq increases due to the internal heat exchanger 58. That is, the refrigerator 1 of the first embodiment can obtain the effects of improving the cooling capacity and the energy saving performance due to the internal heat exchanger 58 described in relation to the cooling operation.

[0101] <Main Features of the Refrigerator 1 of the First Embodiment> (1) As shown in FIG. 6C, the refrigerator 1 of the first embodiment includes a refrigerator compartment 2 (FIG. 1), a freezer compartment 7 (FIG. 1), a compressor 24, a heat dissipation means 50, an R evaporator 14a (refrigerating cooler), an F evaporator 14b (freezing cooler), and a defrosting pipe 102. The compressor 24 is a component that compresses the refrigerant. The heat dissipation means 50 is a component that releases heat from the refrigerant. The R evaporator 14a is a refrigerating evaporator that evaporates the refrigerant during a refrigerating cooling operation to cool the refrigerator compartment 2. The F evaporator 14b is a freezing evaporator that evaporates the refrigerant during a freezing cooling operation to cool the freezer compartment 7. The defrosting pipe 102 is a component that exchanges heat with the F evaporator 14b during a defrosting operation. The defrosting operation is an operation for removing frost adhering to the F evaporator 14b by causing the refrigerant discharged from the compressor 24 to flow through the defrosting pipe 102, the R evaporator 14a, and the compressor 24 in that order. The flow path resistance R1 of the refrigerant path FP8 connecting the outlet Out102 of the defrosting pipe 102 to the inlet In14a of the R evaporator 14a is set lower than the flow path resistance R2 of the refrigerant paths FP3 and FP4a connecting the outlet Out50 of the heat dissipation means 50 to the inlet In14a of the R evaporator 14a.

[0102] In the refrigerator 1 of the first embodiment, the flow resistance R1 of the refrigerant path FP8 is set lower than the flow resistance R2 of the refrigerant paths FP3 and FP4. Therefore, in the refrigerator 1 of the first embodiment, the refrigerant discharged from the compressor 24 can flow smoothly while being heated by the F evaporator 14b during the defrosting operation, and the amount of refrigerant used for defrosting can be increased. In the refrigerator 1 of the first embodiment, defrosting can be performed in a short time and with higher heating efficiency during the defrosting operation.

[0103] (2) As shown in FIG. 6C, the refrigerator 1 of the first embodiment further includes a refrigerant flow path FP, an R capillary tube 53a, an F capillary tube 53b, a three-way valve 52, and a three-way valve 101. The refrigerant flow path FP is a flow path through which the refrigerant flows. The R capillary tube 53a is a refrigeration pressure reducing means that reduces the pressure of the refrigerant during refrigeration cooling. The F capillary tube 53b is a freezing pressure reducing means that reduces the pressure of the refrigerant during freezing cooling. The three-way valve 52 is a first refrigerant control means that switches the direction in which the refrigerant discharged from the heat dissipation means 50 flows to either the direction of the R capillary tube 53a (refrigeration pressure reducing means) or the direction of the F capillary tube 53b (freezing pressure reducing means). The three-way valve 101 is provided between the compressor 24 and the three-way valve 52 (first refrigerant control means), and is a second refrigerant control means that switches the flow direction of the refrigerant discharged from the compressor 24 to either the direction to the heat dissipation means 50 or the direction to the defrosting pipe 102. The refrigerant flow path FP is configured to flow the refrigerant discharged from the compressor 24 through the three-way valve 101 (second refrigerant control means), the heat dissipation means 50, the three-way valve 52 (first refrigerant control means), the R capillary tube 53a (refrigeration pressure reduction means), the R evaporator 14a, and the compressor 24 in this order during refrigeration cooling operation. Moreover, the refrigerant flow path FP is configured to allow the refrigerant discharged from the compressor 24 to flow, during a freezing and cooling operation, through the three-way valve 101 (second refrigerant control means), the heat dissipation means 50, the three-way valve 52 (first refrigerant control means), the F capillary tube 53b (freezing pressure reduction means), the F evaporator 14b, and the compressor 24 in that order. Moreover, the refrigerant flow path FP is configured to allow the refrigerant discharged from the compressor 24 to flow, during a defrosting operation, through the three-way valve 101 (second refrigerant control means), the defrosting pipe 102, the R evaporator 14a, and the compressor 24 in that order.

[0104] The refrigerator 1 of the first embodiment described above can realize a configuration that performs defrosting in a short time and with high heating efficiency.

[0105] (3) As shown in Fig. 6C, the refrigerator 1 of the first embodiment further includes a junction 105 and a check valve 104. The junction 105 is a portion where a pipe on a refrigerant path FP4 connecting the compressor 24 to the R evaporator 14a and a pipe on a refrigerant path FP8 connecting the defrost pipe 102 to the R evaporator 14a join (connect). The check valve 104 is a component that suppresses the inflow of refrigerant into the defrost pipe 102 during cooling operation. The check valve 104 is provided between the junction 105 and the defrost pipe 102.

[0106] The refrigerator 1 of the first embodiment includes a check valve 104 between the junction 105 and the F evaporator 14b. The refrigerator 1 of the first embodiment can suppress the refrigerant from moving (moving in the reverse direction) toward the F evaporator 14b (evaporator for freezing and cooling) during cooling operation. This allows the refrigerator 1 of the first embodiment to prevent the refrigerant from running short during cooling operation.

[0107] (4) As shown in FIG. 4A, in the refrigerator 1 of the first embodiment, the defrosting pipe 102 is expanded so as to come into contact with the fins provided on the F evaporator 14b with high efficiency.

[0108] The refrigerator 1 of the first embodiment can bring the fins of the F evaporator 14b into contact with the defrosting pipe 102 with high efficiency. Therefore, the refrigerator 1 of the first embodiment can increase the amount of heat exchanged between the fins of the F evaporator 14b and the refrigerant in the defrosting pipe 102. The refrigerator 1 of the first embodiment can perform defrosting in a short time and with high heating efficiency during defrosting operation.

[0109] (5) As shown in Fig. 6C, the refrigerator 1 of the first embodiment further includes a defrosting capillary tube 103 (defrosting pressure reduction means) which is provided between the defrosting pipe 102 and the R evaporator 14a and reduces the pressure of the refrigerant during defrosting operation. The flow resistance R103 of the defrosting capillary tube 103 (defrosting pressure reduction means) is set lower than the flow resistance R53a of the R capillary tube 53a (refrigeration pressure reduction means).

[0110] In the refrigerator 1 of the first embodiment, the flow resistance R103 of the defrosting capillary tube 103 (defrosting pressure reduction means) is set lower than the flow resistance R53a of the R capillary tube 53a (refrigeration pressure reduction means). Therefore, the refrigerator 1 of the first embodiment can increase the amount of refrigerant used for defrosting, thereby increasing the amount of heat dissipated (amount of heat) from the refrigerant. The refrigerator 1 of the first embodiment can perform defrosting in a short time with even higher heating efficiency.

[0111] (6) As shown in Fig. 6C, the refrigerator 1 of the first embodiment further includes an internal heat exchanger 58 (heat exchanger). The internal heat exchanger 58 (heat exchanger) is a component that performs heat exchange between refrigerant passages FP3 and FP4a extending from the outlet Out102 of the defrosting pipe 102 to the inlet In14a of the R evaporator 14a and a refrigerant passage FP8 extending from the R evaporator 14a to the compressor 24 during a defrosting operation.

[0112] The refrigerator 1 of the first embodiment can heat the refrigerant returning to the compressor 24 in the internal heat exchanger 58. Therefore, the refrigerator 1 of the first embodiment can increase the amount of heat of the refrigerant returning to the compressor 24 and improve energy saving performance. The refrigerator 1 of the first embodiment can perform defrosting in a short time and with high heating efficiency.

[0113] (7) As shown in FIG. 6C, the refrigerator 1 of the first embodiment includes a refrigerator compartment 2 (FIG. 1), a freezer compartment 7 (FIG. 1), a compressor 24, an R evaporator 14a (refrigerating cooler), an F evaporator 14b (freezing cooler), a refrigerant flow path FP, an R capillary tube 53a (refrigerating pressure reduction means), and an F capillary tube 53b (freezing pressure reduction means). The compressor 24 is a component that compresses the refrigerant. The heat dissipation means 50 is a component that releases heat from the refrigerant. The R evaporator 14a is a refrigerating evaporator that evaporates the refrigerant during a refrigerating cooling operation to cool the refrigerator compartment 2. The F evaporator 14b is a freezing evaporator that evaporates the refrigerant during a refrigerating cooling operation to cool the freezer compartment 7. The refrigerant flow path FP is a flow path through which the refrigerant flows. The R capillary tube 53a is a refrigerating pressure reduction means that reduces the pressure of the refrigerant during refrigerating cooling. The F capillary tube 53b is a refrigeration pressure reducing means that reduces the pressure of the refrigerant during refrigeration and cooling. The refrigerant flow path FP is configured to flow the refrigerant by bypassing a part or all of the R capillary tube 53a (refrigeration pressure reducing means) and the F capillary tube 53b (refrigeration pressure reducing means) during defrosting operation. For example, in the example shown in FIG. 6C, the refrigerant flow path FP is configured to flow the refrigerant through the defrosting capillary tube 103 (defrosting pressure reducing means) during defrosting operation instead of bypassing the R capillary tube 53a and the F capillary tube 53b entirely. The defrosting operation is an operation in which the refrigerant discharged from the compressor 24 is heat-exchanged with the F evaporator 14b, and then flows through the R evaporator 14a and the compressor 24 in this order to remove frost adhering to the F evaporator 14b.

[0114] The refrigerator 1 of the first embodiment can adjust the amount of pressure reduction of the refrigerant during the defrosting operation. Therefore, the refrigerator 1 of the first embodiment can increase the amount of refrigerant used for defrosting. The refrigerator 1 of the first embodiment can perform defrosting in a short time and with higher heating efficiency during the defrosting operation.

[0115] As shown in FIG. 11, the refrigerator 1A of the second embodiment described later has the feature of this section (8) like the refrigerator 1 of the first embodiment (FIG. 6C). That is, the refrigerator 1A of the second embodiment described later (FIG. 11) includes the refrigerator compartment 2 (FIG. 1), the freezer compartment 7 (FIG. 1), the compressor 24, the R evaporator 14a (refrigerating cooler), the F evaporator 14b (freezing cooler), the refrigerant flow path FP, the R capillary tube 53a (refrigerating pressure reduction means), and the F capillary tube 53b (freezing pressure reduction means). In the refrigerator 1A of the second embodiment described later (FIG. 11), the refrigerant flow path FP is configured to bypass a part or all of the R capillary tube 53a (refrigerating pressure reduction means) and the F capillary tube 53b (freezing pressure reduction means) during defrosting operation. For example, in the example shown in Fig. 11, the refrigerant flow path FP is configured to make the refrigerant flow via the defrosting capillary tube 103 (defrosting pressure reducing means) during defrosting operation, instead of bypassing the R capillary tube 53a and the F capillary tube 53b entirely. The refrigerator 1A of the second embodiment described below can increase the amount of refrigerant used for defrosting, similarly to the refrigerator 1 of the first embodiment (Fig. 6C), and can perform defrosting in a short time and with higher heating efficiency during defrosting operation.

[0116] (8) As shown in FIG. 6C, the refrigerator 1 of the first embodiment further includes a defrosting capillary tube 103 (defrosting pressure reducing means) and a junction 105. The defrosting capillary tube 103 is a defrosting pressure reducing means that reduces the pressure of the refrigerant during defrosting operation. The junction 105 is a portion where a pipe on the refrigerant path FP4 connecting the compressor 24 to the R evaporator 14a and a pipe on the refrigerant path FP8 connecting the F evaporator 14b to the R evaporator 14a join (connect). The defrosting capillary tube 103 is provided in a flow path until the refrigerant after heat exchange with the F evaporator 14b reaches the junction 105 during defrosting operation. The R capillary tube 53a is provided between the compressor 24 and the junction 105 on the refrigerant path FP4 connecting the compressor 24 to the R evaporator 14a during cooling operation. The flow resistance R103 of the defrosting capillary tube 103 is set lower than the flow resistance R53a of the R capillary tube 53a.

[0117] In the refrigerator 1 of the first embodiment, the flow resistance R103 of the defrosting capillary tube 103 is set lower than the flow resistance R53a of the R capillary tube 53a. Therefore, the refrigerator 1 of the first embodiment can increase the amount of refrigerant used for defrosting, thereby increasing the amount of heat dissipated (amount of heat) from the refrigerant. The refrigerator 1 of the first embodiment can perform defrosting in a short time and with even higher heating efficiency during defrosting operation.

[0118] As described above, according to the refrigerator 1 of the first embodiment, defrosting can be performed in a short time with high heating efficiency.

[0119] [Second Example] The refrigerator 1 (FIG. 5) of the first embodiment includes a defrosting pipe 102, and is configured to exchange heat between the F evaporator 14b and the refrigerant in the defrosting pipe 102. In contrast, in the second embodiment, the defrosting pipe 102 is eliminated, and instead, a refrigerator 1A (FIG. 11) is provided in which the refrigerant is caused to flow inside the F evaporator 14b, thereby exchanging heat between the F evaporator 14b and the refrigerant.

[0120] Hereinafter, the configuration of the refrigerator 1A of the second embodiment will be described with reference to Fig. 11. Fig. 11 is a schematic diagram showing the configuration of a refrigeration cycle (refrigerant flow path) in the refrigerator 1A of the second embodiment. The refrigerator 1A of the second embodiment is configured to heat and thaw frost adhering to the F evaporator 14b by flowing high-temperature refrigerant discharged from the compressor 24 during defrosting operation into the F evaporator refrigerant pipe 59 of the F evaporator 14b used during cooling operation.

[0121] As shown in FIG. 11, the refrigerator 1A of the second embodiment differs from the refrigerator 1 of the first embodiment (FIG. 5) in the following points. (1) The defrosting pipe 102 and the refrigerant flow paths FP31 to FP38 are provided instead of the refrigerant flow paths FP1 to FP8. (2) A two-way valve 112 is provided between the F gas-liquid separator 54b and the check valve 55.

[0122] The refrigerant flow path FP31 is configured to connect from the compressor 24 to the three-way valve 101. The refrigerant flow path FP32 is configured to connect from the three-way valve 101 to the dew condensation prevention pipe 50c of the heat radiation means 50 through the outdoor radiator 50a and the wall surface heat radiation pipe 50b of the heat radiation means 50. The refrigerant flow path FP33 is configured to connect from the dew condensation prevention pipe 50c of the heat radiation means 50 to the three-way valve 52 through the dryer 51. The refrigerant flow path FP34 is configured to connect from the three-way valve 52 to the refrigerant confluence section 113 through the R capillary tube 53a, the R evaporator 14a, and the R gas-liquid separator 54a. The refrigerant confluence section 113 is a part where the refrigerant flow path FP34 and the refrigerant flow path FP35 merge (connect). The refrigerant flow path FP34 includes a refrigerant flow path FP34a that connects from the three-way valve 52 to the confluence section 105, and a refrigerant flow path FP34b that connects from the confluence section 105 to the refrigerant confluence section 113. The refrigerant flow path FP35 is configured to connect from the three-way valve 52 to the refrigerant confluence section 113 through the F capillary tube 53b, the F evaporator 14b, the F gas-liquid separator 54b, and the check valve 55. The refrigerant flow path FP35 includes a refrigerant flow path FP35a that connects from the three-way valve 52 to the confluence section 110, and a refrigerant flow path FP35b that connects from the confluence section 110 to the refrigerant confluence section 113. The refrigerant flow path FP36 is configured to connect from the refrigerant confluence section 113 to the compressor 24. The refrigerator 1A is configured such that the R capillary tube 53a, the F capillary tube 53b, and the defrosting capillary tube 103 can perform heat exchange with the refrigerant flow path FP36 (the suction pipe 57) in the internal heat exchange section 58. The refrigerant flow path FP37 is configured to connect from the three-way valve 101 to the confluence section 110. The confluence section 110 is a part where the refrigerant flow path FP37 and the refrigerant flow path FP35 merge (connect). The refrigerant flow path FP38 is configured to connect the branching portion 111 to the junction portion 105 through the defrosting capillary tube 103 and the check valve 104. The branching portion 111 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.

[0123] The two-way valve 112 is a refrigerant passage blocking means. The two-way valve 112 selectively opens and closes to function as a third refrigerant passage control means for switching the refrigerant flow direction between the direction of the refrigerant junction 113 (i.e., the direction of the refrigerant passage FP36) and the direction of the R evaporator 14a (i.e., the direction of the refrigerant passage FP38).

[0124] The refrigerator 1A is configured to connect a junction 110 provided between the F capillary tube 53b and the F evaporator 14b and an outlet 101b of the three-way valve 101 by a refrigerant flow path FP. The refrigerator 1A is also configured to connect a branch 111 provided downstream of the F evaporator 14b and a defrosting capillary tube 103 by the refrigerant flow path FP. The refrigerator 1A is also configured such that a pipe on the refrigerant path connecting the R evaporator 14a to the compressor 24 and a pipe on the refrigerant path connecting the F evaporator 14b to the compressor 24 join (connect) at a refrigerant junction 113. The refrigerator 1A is also provided with a two-way valve 112 between the branch 111 and the refrigerant junction 113. The two-way valve 112 is open (opened) during a freezing / cooling operation and closed (closed) during a defrosting operation. Other parts of the refrigerator 1A of the second embodiment are the same as those of the refrigerator 1 of the first embodiment (FIG. 5).

[0125] In the refrigerator 1A of the second embodiment, during defrosting operation, the outlet 101b side of the three-way valve 101 is opened and the two-way valve 112 is closed. This causes the high-temperature refrigerant from the compressor 24 to flow directly into the F evaporator 14b and heat the F evaporator 14b. The subsequent refrigerant flows to the defrosting capillary tube 103 side because the two-way valve 112 side is closed, and absorbs heat by the R evaporator 14a.

[0126] In the refrigerator 1A of the second embodiment, the high-temperature refrigerant from the compressor 24 heats the F evaporator 14b, and the R evaporator 14a absorbs heat during the heating, as in the refrigerator 1 of the first embodiment, to realize a defrosting operation. In the refrigerator 1A of the second embodiment, the R capillary tube 53a, the F capillary tube 53b, and the defrosting capillary tube 103 exchange heat with the refrigerant flow path FP36 in the internal heat exchanger 58, as in the refrigerator 1 of the first embodiment. The state of the refrigeration cycle of the refrigerator 1A of the second embodiment is similar to the state of the refrigeration cycle of the refrigerator 1 of the first embodiment shown in Figs. 7 and 10. Therefore, the refrigerator 1A of the second embodiment has the same effect as the refrigerator 1 of the first embodiment. Therefore, the effect of the refrigerator 1 of the first embodiment is not limited to the F evaporator 14b having the defrosting pipe 102, and can be achieved as long as the refrigerator 1 of the first embodiment can heat the F evaporator 14b with the refrigerant discharged from the compressor 24.

[0127] In addition, comparing refrigerator 1 of the first embodiment with refrigerator 1A of the second embodiment, refrigerator 1 of the first embodiment is configured not to use two-way valve 112, unlike refrigerator 1A of the second embodiment. In this respect, refrigerator 1 of the first embodiment may be able to reduce space and costs compared to refrigerator 1A of the second embodiment by the amount that does not use two-way valve 112.

[0128] In contrast, the refrigerator 1A of the second embodiment can use a general evaporator not provided with the defrosting pipe 102 as the F evaporator 14b. Therefore, the refrigerator 1A of the second embodiment can reduce the cost of the F evaporator 14b accordingly, and can improve the versatility and design freedom of the F evaporator 14b.

[0129] As described above, according to the refrigerator 1A of the second embodiment, like the refrigerator 1 of the first embodiment (FIG. 5), defrosting can be performed in a short time and with higher heating efficiency. Moreover, according to the refrigerator 1A of the second embodiment, compared to the refrigerator 1 of the first embodiment (FIG. 5), a general evaporator not provided with a defrosting pipe 102 can be used as the F evaporator 14b, so that the cost of the F evaporator 14b can be reduced accordingly, and the versatility and freedom of design of the F evaporator 14b can be improved.

[0130] The present invention is not limited to the above-described embodiment, and includes various modified examples. For example, the above-described embodiment has been described in detail to easily explain the present invention, and is not necessarily limited to having all of the configurations described. In addition, it is possible to replace a part of the configuration of the embodiment with another configuration, and it is also possible to add another configuration to the configuration of the embodiment. In addition, it is possible to add, delete, or replace a part of each configuration with another configuration.

[0131] For example, the pressure reducer of the refrigerator may be provided with an expansion valve (not shown) capable of controlling pressure instead of a capillary tube. Such a refrigerator can adjust the pressure of the refrigerant as necessary. [Explanation of symbols]

[0132] 1,1A,1001,1002 Refrigerator 2 Refrigerator 7 Freezer 8a R Evaporator compartment (refrigerated evaporator compartment) 8b F evaporator chamber (refrigeration evaporator chamber) 14a R Evaporator (refrigerated evaporator, refrigerated cooler) 14b F evaporator (refrigeration evaporator, refrigeration cooler) 24 Compressor 31 Control board (control device, control unit) 50 Heat dissipation means 50a External radiator 50b Wall heat dissipation piping 50c Condensation prevention piping 51 Dryer 52 Three-way valve (first refrigerant control means) 52a,52b,101a,101b Outlet 53 Capillary tube (pressure reducing means) 53a R Capillary tube (refrigeration pressure reduction means) 53b F capillary tube (reducing pressure means for refrigeration) 54a R gas-liquid separator 54b F gas-liquid separator 55,104,204 Check valve 56,113 Refrigerant merging, 57 Suction pipe 58 Internal heat exchange section (heat exchange section) 59 F evaporator refrigerant piping 101 Three-way valve (second refrigerant control means) 102 Defrosting pipe (refrigerant pipe) 103 Defrosting capillary tube (defrosting pressure reducing means) 105, 106, 110, 113 Junction 111 Branch 112 Two-way valve (refrigerant flow passage blocking means, third refrigerant flow passage control means) 120 Fin 201 Three-way valve 203 Defrosting capillary tube (defrosting pressure reducing means) In14a entrance Out50 exit R1, R2, R53a, R103 Flow path resistance

Claims

1. A refrigerator compartment, A freezer and A compressor that compresses a refrigerant; A heat dissipation means for dissipating heat from the refrigerant; a refrigeration evaporator that evaporates a refrigerant during a refrigeration cooling operation for cooling the refrigeration compartment; a freezing evaporator that evaporates a refrigerant during a freezing / cooling operation for cooling the freezing compartment; A defrosting pipe is disposed inside or near the refrigeration evaporator and exchanges heat between the defrosting pipe and the refrigeration evaporator. During a defrosting operation, the refrigerant discharged from the compressor is caused to flow through the defrosting pipe, the refrigeration evaporator, and the compressor in this order, thereby heating the refrigeration evaporator and removing frost adhering to the refrigeration evaporator, A flow resistance of a refrigerant path connecting the outlet of the defrosting pipe to the inlet of the refrigeration evaporator is set lower than a flow resistance of a refrigerant path connecting the outlet of the heat dissipation means to the inlet of the refrigeration evaporator. A refrigerator characterized by:

2. In the refrigerator according to claim 1, a refrigerant flow path through which a refrigerant flows; A refrigeration pressure reducing means for reducing the pressure of the refrigerant during refrigeration and cooling; A refrigeration pressure reducing means for reducing the pressure of the refrigerant during refrigeration and cooling; a first refrigerant control means for switching a flow direction of the refrigerant discharged from the heat dissipation means to either the flow direction of the refrigeration pressure reduction means or the flow direction of the freezing pressure reduction means; A second refrigerant control means is provided between the compressor and the first refrigerant control means, and switches the direction of the refrigerant discharged from the compressor to either the direction of the heat dissipation means or the direction of the defrosting pipe. The refrigerant flow path is During a refrigeration / cooling operation, the refrigerant discharged from the compressor is configured to flow through the second refrigerant control means, the heat dissipation means, the first refrigerant control means, the refrigeration pressure reducing means, the refrigeration evaporator, and the compressor in this order, During a refrigeration / cooling operation, the refrigerant discharged from the compressor is configured to flow through the second refrigerant control means, the heat dissipation means, the first refrigerant control means, the refrigeration pressure reducing means, the refrigeration evaporator, and the compressor in this order. During a defrosting operation, the refrigerant discharged from the compressor is configured to flow through the second refrigerant control means, the defrosting pipe, the refrigeration evaporator, and the compressor in this order. A refrigerator characterized by:

3. In the refrigerator according to claim 1, a junction portion where a pipe on a refrigerant path connecting the compressor to the refrigeration evaporator and a pipe on a refrigerant path connecting the defrosting pipe to the refrigeration evaporator join together; A check valve is provided between the junction and the defrosting pipe. A refrigerator characterized by:

4. In the refrigerator according to claim 1, The defrosting pipe is expanded so as to come into contact with the fins provided on the refrigeration evaporator with high efficiency. A refrigerator characterized by:

5. In the refrigerator according to claim 2, Further comprising a defrosting pressure reducing means provided between the defrosting pipe and the refrigeration evaporator and configured to reduce the pressure of the refrigerant during a defrosting operation, The flow resistance of the defrosting pressure reducing means is set lower than the flow resistance of the refrigeration pressure reducing means. A refrigerator characterized by:

6. In the refrigerator according to claim 1, The cooling system further includes a heat exchange unit that performs heat exchange between a refrigerant flow path from an outlet of the defrosting pipe to an inlet of the refrigeration evaporator and a refrigerant flow path from the refrigeration evaporator to the compressor during a defrosting operation. A refrigerator characterized by:

7. A refrigerator compartment, A freezer and A compressor that compresses a refrigerant; a refrigeration evaporator that evaporates a refrigerant during a refrigeration cooling operation for cooling the refrigeration compartment; a freezing evaporator that evaporates a refrigerant during a freezing / cooling operation for cooling the freezing compartment; a refrigerant flow path through which a refrigerant flows; A refrigeration pressure reducing means for reducing the pressure of the refrigerant during refrigeration and cooling operation; A refrigeration pressure reducing means for reducing the pressure of the refrigerant during a refrigeration / cooling operation, The refrigerant flow path is configured to flow the refrigerant discharged from the compressor through the refrigeration evaporator and then through the refrigeration evaporator and the compressor in this order during a defrosting operation to remove frost adhering to the refrigeration evaporator, bypassing the refrigeration pressure reducing means and a part or all of the refrigeration pressure reducing means. A refrigerator characterized by:

8. The refrigerator according to claim 7, a defrosting pressure reducing means for reducing the pressure of the refrigerant during a defrosting operation; A junction where a piping on a refrigerant path connecting the compressor to the refrigeration evaporator in a cooling operation and a piping on a refrigerant path connecting the compressor to the refrigeration evaporator in a defrosting operation join together, The defrosting pressure reducing means is provided in a flow path of the refrigerant after heat exchange with the refrigeration evaporator during a defrosting operation until the refrigerant reaches the junction, the refrigeration pressure reducing means is provided between the compressor and the junction on a refrigerant path connecting the compressor to the refrigeration evaporator during a cooling operation, The flow resistance of the defrosting pressure reducing means is set lower than the flow resistance of the refrigeration pressure reducing means. A refrigerator characterized by:

9. A refrigerator compartment, A freezer and A compressor that compresses a refrigerant; A heat dissipation means for dissipating heat from the refrigerant; a refrigeration evaporator that evaporates a refrigerant during a refrigeration cooling operation for cooling the refrigeration compartment; a freezing evaporator that evaporates a refrigerant during a freezing / cooling operation for cooling the freezing compartment; A refrigeration pressure reducing means for reducing the pressure of the refrigerant during refrigeration and cooling; A refrigeration pressure reducing means for reducing the pressure of the refrigerant during refrigeration and cooling; A defrosting pressure reducing means for reducing the pressure of the refrigerant during a defrosting operation for removing frost adhering to the refrigeration evaporator; a first refrigerant control means for switching a flow direction of the refrigerant discharged from the heat dissipation means to either the flow direction of the refrigeration pressure reduction means or the flow direction of the freezing pressure reduction means; a second refrigerant control means provided between the compressor and the first refrigerant control means and configured to switch the direction of flow of the refrigerant discharged from the compressor to either one of the direction to the heat dissipation means or the direction to the refrigeration evaporator; and a refrigerant path through which the refrigerant discharged from the compressor flows in the order of the freezing evaporator, the defrosting pressure reducing means, the refrigerating evaporator, and the compressor during a defrosting operation. A refrigerator characterized by:

10. The refrigerator according to claim 9, a refrigerant junction where a pipe on a refrigerant path connecting the refrigeration evaporator to the compressor and a pipe on a refrigerant path connecting the refrigeration evaporator to the compressor join together; a third refrigerant flow path control means arranged between the freezing evaporator and the refrigerant junction and configured to switch the direction of the refrigerant flow to one of the direction toward the refrigerant junction and the direction toward the refrigeration evaporator. A refrigerator characterized by:

Images