refrigerator

Abstract

To provide a refrigerator that enhances defrosting efficiency of a refrigerating evaporator, and has high energy saving performance.SOLUTION: A refrigerator comprises a heat insulation box body provided with a heat insulation material between an inner box and an outer box, a refrigerating temperature zone chamber formed in the heat insulation box body, a refrigerating evaporator for cooling the refrigerating temperature zone chamber, an air blower for blowing cool air cooled by the refrigerating evaporator to the refrigerating temperature zone chamber, and a compressor for compressing a refrigerant. The air blower is operated while the compressor is stopped, and thereby the refrigerating evaporator is defrosted. A liquid refrigerant in the refrigerating evaporator is discharged by gravity during the stop of the compressor.SELECTED DRAWING: Figure 8

Description

[Technical field]

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

[0002] A refrigerator is equipped with an insulated box having a storage compartment and an insulated door for opening and closing the storage compartment, and cools the air in the storage compartment by a refrigeration cycle consisting of a compressor, a condenser, a pressure reducing means, and an evaporator. Since frost grows on the cooler, a defrosting operation is periodically performed.

[0003] During defrosting operation of such refrigerators, the amount of liquid refrigerant in the evaporator is controlled to reduce the heat load for defrosting and improve the defrosting efficiency. For example, Patent Document 1 describes that "in a refrigerator including a freezing compartment, a freezing evaporator for cooling the freezing compartment, a refrigerator compartment provided below the freezing compartment, and a freezing evaporator for cooling the refrigerator compartment, a compressor, a radiator, a pressure reducing means, the freezing evaporator for freezing, and the freezing evaporator for freezing are connected by refrigerant piping, and the refrigerator includes a refrigeration cycle in which the refrigeration evaporator for freezing and the refrigeration evaporator for freezing are connected in series, and a refrigerant circulation suppression means for suppressing refrigerant circulation when the compressor is stopped is provided in the piping connecting the refrigeration evaporator for freezing and the refrigeration evaporator for freezing."

[0004] Patent Document 2 describes that "When defrosting a refrigerator, the refrigerant flow path to the evaporator on the side to be defrosted is closed by the three-way valve and the compressor is operated to recover the refrigerant in the evaporator on the side to be defrosted, and after the refrigerant is recovered, the compressor is stopped and the evaporator is defrosted by the defrost heater." [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-204874 A [Patent Document 2] JP 2002-71262 A Summary of the Invention [Problem to be solved by the invention]

[0006] The refrigerator disclosed in Patent Document 1 improves energy saving performance by suppressing heat transfer between evaporators while the compressor is stopped. However, the refrigerator disclosed in Patent Document 1 has a problem that liquid refrigerant remains in the refrigeration evaporator when starting a defrosting operation of a refrigerator compartment that requires frequent defrosting operations, and energy is required to evaporate the liquid refrigerant in order to melt the frost.

[0007] In the refrigerator disclosed in Patent Document 2, the amount of refrigerant in the evaporator to be defrosted is reduced by recovering the refrigerant, thereby improving the defrosting efficiency. However, in the refrigerator disclosed in Patent Document 2, it is necessary to operate the compressor for about several minutes to recover the refrigerant, which causes a problem of degraded energy saving performance.

[0008] An object of the present invention is to improve the defrosting efficiency of a refrigeration evaporator and provide a refrigerator with high energy-saving performance. [Means for solving the problem]

[0009] In order to solve such problems, the present invention provides a refrigerator comprising an insulated box body having an insulating material provided between an inner box and an outer box, a refrigeration temperature zone compartment formed within the insulated box body, a refrigeration evaporator that cools the refrigeration temperature zone compartment, a blower that blows cold air cooled by the refrigeration evaporator into the refrigeration temperature zone compartment, and a compressor that compresses a refrigerant, wherein the blower operates while the compressor is stopped to defrost the refrigeration evaporator, and is characterized in that liquid refrigerant in the refrigeration evaporator is discharged by gravity while the compressor is stopped. Effect of the Invention

[0010] According to the present invention, the liquid refrigerant in the refrigeration evaporator can be reduced without the power of a compressor, so that the defrosting efficiency of the refrigeration evaporator is improved, and a refrigerator with high energy-saving performance can be provided. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a front view of a refrigerator according to a first embodiment. [Diagram 2] 2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 3] FIG. 1 is a configuration diagram of a refrigeration cycle of a refrigerator according to a first embodiment. [Figure 4] FIG. 2 is a perspective view of a freezing evaporator of the refrigerator according to the first embodiment. [Diagram 5] FIG. 2 is a side view of a refrigeration evaporator of the refrigerator according to the first embodiment. [Figure 6] FIG. 2 is a perspective view of a cooling surface of a second evaporator of the refrigerator according to the first embodiment. [Figure 7] 2 is a cross-sectional view of a heat transfer tube of an evaporator of the refrigerator according to the first embodiment. FIG. [Figure 8] FIG. 2 is a layout diagram of refrigeration cycle components of the refrigerator according to the first embodiment, as viewed from the front. [Figure 9] FIG. 11 is a configuration diagram of a refrigeration cycle of a refrigerator according to a second embodiment. [Figure 10] FIG. 11 is a layout diagram of refrigeration cycle components of a refrigerator according to a second embodiment, as viewed from the front. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. EXAMPLES

[0013] A refrigerator 1 according to a first embodiment of the present invention will be described with reference to Figs. 1 to 8.

[0014] Fig. 1 is a front view of a refrigerator according to a first embodiment. As shown in Fig. 1, the refrigerator 1 of this embodiment is composed of, from the top, a refrigerator compartment 2, an ice-making compartment 3, an upper freezer compartment 4, a lower freezer compartment 5, and a vegetable compartment 6, which are arranged on the left and right sides, in that order. The temperatures inside the ice-making compartment 3, the upper freezer compartment 4, and the lower freezer compartment 5 are basically in the freezing temperature range (less than 0°C), for example, about -18°C on average. The temperatures inside the refrigerator compartment 2 and the vegetable compartment 6 are in the refrigeration temperature range (0°C or higher), for example, the refrigerator compartment 2 is about 4°C on average, and the vegetable compartment 6 is about 7°C on average.

[0015] The refrigerator compartment 2 is divided into left and right compartments and has a rotating refrigerator compartment door 2a that opens like a double door, while the ice making compartment 3, upper freezer compartment 4, lower freezer compartment 5, and vegetable compartment 6 are each equipped with a pull-out ice making compartment door 3a, upper freezer compartment door 4a, lower freezer compartment door 5a, and vegetable compartment door 6a. The interior material of these multiple doors is made of urethane.

[0016] Fig. 2 is a cross-sectional view taken along the line AA in Fig. 1. The outside and inside of the refrigerator 1 are separated by a thermal insulation box 9 formed by filling a foam insulation material (e.g., urethane foam) between an outer box 9a and an inner box 9b. In addition to the foam insulation material, multiple vacuum insulation materials 10 are mounted between the outer box 9a and the inner box 9b to provide high insulation. Here, the vacuum insulation material 10 is formed by wrapping a core material such as glass wool or urethane in an outer packaging material.

[0017] The storage compartments are separated by heat-insulating partition walls 11a, 11b, 11c, and 11d. In front of the heat-insulating partition walls 11a, 11b, 11c, and 11d, partition covers 12 are provided. A plurality of door pockets 13 are provided on the inside of the refrigerator compartment door 2a, and a plurality of shelves 14 are provided in the refrigerator compartment 2, dividing the compartment into a plurality of storage spaces.

[0018] The upper freezer compartment 4, the lower freezer compartment 5 and the vegetable compartment 6 are each provided with a storage container 4b, 5b, 6b that moves together with the door provided at the front of the compartment, and the storage containers 4b, 5b, 6b can also be pulled out by pulling the door forward. The ice-making compartment 3 (not shown) is also provided with a storage container that moves together with the door, and the storage container 3b can also be pulled out by pulling the door forward.

[0019] Above the heat-insulating partition wall 11a, there is provided an ice temperature compartment 8 which is set to a temperature lower than the temperature zone of the refrigerator compartment 2. The ice temperature compartment 8 is switched between a mode for setting the temperature in the refrigeration temperature zone, for example, about 0 to 4°C, and a mode for setting the temperature in the freezing temperature zone, for example, about -3 to 0°C, by, for example, control of the second evaporator 15b and the second blower 16b, and a heater (not shown) provided inside the heat-insulating partition wall 11a.

[0020] The first evaporator 15a (freezing evaporator) is provided on the rear side of the lower freezer compartment 5, and cools the ice making compartment 3, the upper freezer compartment 4, and the lower freezer compartment 5, which are freezing temperature zone compartments, as well as the vegetable compartment 6, which is a refrigerating temperature zone compartment, and the refrigerator compartment 2 as necessary. The first blower 16a provided above the first evaporator 15a blows the cold air that has exchanged heat with the first evaporator 15a to the refrigerator compartment 2, the ice making compartment 3, the upper freezer compartment 4, the lower freezer compartment 5, and the vegetable compartment 6 through the refrigerator compartment cold air duct 17, the freezer compartment cold air duct 18, and the vegetable compartment cold air duct (not shown). In this embodiment, the first blower 16a is in the form of a propeller fan, which efficiently blows cold air in the axial direction. In the following, the ice making compartment 3, the upper freezer compartment 4, and the lower freezer compartment 5 will be collectively referred to as the freezing temperature zone compartments 7.

[0021] The blowing of cold air to the refrigerator compartment 2 is controlled by opening and closing the refrigerator compartment damper 20. The refrigerator compartment damper 20 is equipped with a baffle plate 21, and the opening and closing angle of the baffle plate 21 is adjusted by a motor drive to adjust the amount of blown air. The air sent to the refrigerator compartment 2 can be continuously cooled by returning to below the first evaporator 15a. Since the refrigerator compartment 2 is equipped with the second evaporator 15b, when the thermal load is so large that the second evaporator 15b cannot cool the refrigerator compartment 2, the refrigerator compartment damper 20 opens, and the cooling of the refrigerator compartment 2 is promoted.

[0022] The blowing of cool air to the vegetable compartment 6 is controlled by opening and closing a vegetable compartment damper (not shown). The vegetable compartment damper is equipped with a baffle plate (not shown), and the opening and closing angle of the baffle plate is adjusted by a motor drive to adjust the blowing air volume. The air sent to the vegetable compartment 6 can be continuously cooled by returning to the area below the first evaporator 15a.

[0023] A radiant heater 22 is provided below the first evaporator 15a. When frost grows on the surface of the first evaporator 15a and narrows the air passage, the radiant heater 22 is operated to remove the frost.

[0024] The second evaporator 15b (evaporator for refrigeration) is provided on the rear side of the refrigerator compartment 2, and cools the refrigerator compartment 2, which is a refrigerator temperature zone compartment. The second blower 16b provided below the second evaporator 15b blows the cold air that has exchanged heat with the second evaporator 15b into the refrigerator compartment 2 via a refrigerator compartment cold air duct 17. In this embodiment, the second blower 16b is a centrifugal fan that efficiently blows cold air in the circumferential direction (mainly upward).

[0025] Here, the cold air that has exchanged heat with the first evaporator 15a is basically at a low temperature to cool the freezing temperature zone compartment, and the humidity is also low due to the low temperature. However, when the heat load of the refrigerator compartment 2 in this embodiment is not large, it is cooled by the second evaporator 15b. In other words, since the low-humidity cold air that has exchanged heat with the first evaporator 15a does not directly flow into the refrigerator compartment 2, it is possible to keep the refrigerator compartment 2 in a high humidity state.

[0026] Frost that has grown on the cooling surface 33 of the second evaporator 15b can be defrosted without using a heating source such as a heater by operating the second blower 16b without flowing refrigerant through the second evaporator 15b. In addition, since the air blown into the refrigerator compartment 2 during the defrosting operation of the second evaporator 15b is around 0°C (the temperature of the frost), the refrigerator compartment 2 can be cooled at the same time as the defrosting. That is, in this embodiment, since the defrosting operation and the cooling operation of the refrigerator compartment 2 are performed simultaneously while the compressor 25 is stopped, the power consumption is lower than that of a general defrosting operation using a heating source such as a heater. Therefore, even if the defrosting operation of the refrigerator compartment 2 is frequently performed, the energy saving performance is less likely to be impaired. Furthermore, since the refrigerator compartment 2 can be cooled even when the compressor 25 is stopped, it is possible to suppress unsteady temperature fluctuations in the refrigerator compartment 2, and it is possible to control the refrigerator compartment 2 to a chilled temperature range of, for example, 0 to 2 degrees. In addition, the refrigerated compartment 2 can be made highly humid by using the melted frost. Hereinafter, the operation in which the second blower 16b is operated while the compressor 25 is stopped to defrost and cool the refrigerator compartment 2 will be referred to as off-cycle operation.

[0027] A control board 23 is arranged on the rear side of the upper wall of the refrigerator 1, and according to control means stored in the control board 23, ON / OFF and rotation speed control of the compressor 25, the first blower 16a and the second blower 16b, and opening / closing control of the refrigerator compartment damper 20 are performed.

[0028] In a machine room 24 provided below the refrigerator 1, in addition to the compressor 25, a first radiator 26a (not shown in FIG. 2) and an external fan 27 (not shown in FIG. 2) are arranged.

[0029] Fig. 3 is a configuration diagram of a refrigeration cycle of a refrigerator according to the first embodiment. As shown in Fig. 3, the refrigerator 1 of the present embodiment includes a compressor 25 for compressing a refrigerant, a first radiator 26a and a second radiator 26b as heat dissipation means for dissipating heat from the refrigerant, a capillary tube 28 as pressure reduction means for reducing the pressure of the refrigerant, and a first evaporator 15a and a second evaporator 15b for absorbing heat from the inside of the refrigerator by heat exchange between the refrigerant and the air in the refrigerator. The refrigerator 1 further includes a dryer 29 for removing moisture in the refrigeration cycle and a gas-liquid separator 30 for preventing liquid refrigerant from flowing into the compressor 25, and these are connected by a refrigerant pipe 31 to configure a refrigeration cycle.

[0030] The first radiator 26a has a higher heat radiation efficiency than the second radiator 26b because it draws in outside air by the outside air blower 27. The refrigerator 1 of this embodiment uses isobutane as a refrigerant. The compressor 25 of this embodiment is provided with an inverter so that the rotation speed can be changed. In the refrigeration cycle shown in FIG. 3, a capillary tube is given as an example of the pressure reducing means, but an expansion valve or a combination of an expansion valve and a capillary tube may also be used.

[0031] Fig. 4 is a perspective view of a first evaporator of the refrigerator according to the first embodiment. As shown in Fig. 4, the first evaporator 15a is a cross fin tube type heat exchanger, and is configured such that a heat transfer tube 32 that is bent multiple times penetrates a plurality of aluminum fins 34. In addition, a gas-liquid separator 30 is provided on the refrigerant outlet side of the heat transfer tube 32. This first evaporator 15a is disposed in a space between the inner box 9b and the freezing temperature zone compartment 7.

[0032] FIG. 5 is a side view of the second evaporator of the refrigerator according to the first embodiment. As shown in FIG. 5, the second evaporator 15b is composed of a heat transfer tube 32 and a cooling surface 33, and the heat transfer tube 32 of the second evaporator 15b is mounted inside the wall surface of the heat-insulating box 9. The heat transfer tube 32 is bent multiple times, disposed in the foam insulation material between the outer box 9a and the inner box 9b, and contacts the back side of the inner box 9b. Furthermore, the cooling surface 33 is fixed to the refrigerator compartment 2 side of the inner box 9b by adhesive or the like, and the heat transfer tube 32 cools the refrigerator compartment 2 through the cooling surface 33. In this way, by mounting the heat transfer tube 32 of the second evaporator 15b inside the wall surface of the heat-insulating box 9, the cooling system is made smaller and the food storage volume is expanded. In addition, the back side of the second evaporator 15b is provided with a vacuum insulation material 10 to suppress heat absorption from the outside of the refrigerator.

[0033] FIG. 6 is a perspective view of the cooling surface of the second evaporator of the refrigerator according to the first embodiment. As shown in FIG. 6, the cooling surface 33 is provided with fins 34, which increases the heat transfer area and improves the cooling efficiency of the refrigerator compartment 2, thereby improving the energy saving performance of the refrigerator 1. The fins 34 are formed parallel to the flow of cold air, so that the increase in airflow resistance can be suppressed. Furthermore, by using a resin material for the fins 34, the cooling surface temperature is higher than when the fins 34 are made of metal, so that the amount of frost formation on the second evaporator 15b is suppressed and the off-cycle operation time can be shortened. Furthermore, by suppressing the amount of frost formation, dehumidification of the refrigerator compartment 2 is suppressed and the refrigerator compartment 2 can be kept at a high humidity. Furthermore, the higher cold air temperature reduces the risk of freezing of refrigerated foods. For the same reason, it is desirable to use a resin material for the cooling surface 33 as well. However, the thermal conductivity of the cooling surface 33 and the fins 34 is higher than that of the inner box 9b. In this embodiment, the cooling surface 33 and the fins 34 are made of resin to suppress the amount of frost formation, but if priority is given to the cooling performance of the refrigerator compartment 2, they can also be made of metal such as aluminum.

[0034] As described above with reference to Figs. 5 and 6, the first evaporator 15a has a cross fin tube type configuration that can easily improve cooling efficiency, and the second evaporator 15b has a heat transfer tube 32 mounted inside the wall surface of the insulated box 9 to suppress frost growth, and the cooling surface 33 and the like are made of a resin material with low thermal conductivity. That is, on the first evaporator 15a side, the temperature difference between the air and the refrigerant is small (about 5°C) and the growth rate of frost is slow, so improvement of cooling efficiency is prioritized over suppression of frost growth. On the other hand, on the second evaporator 15b side, the temperature difference between the air and the refrigerant is large (about 25°C) and the growth rate of frost is fast, so suppression of frost growth is prioritized over cooling efficiency. In this way, the energy saving performance of the refrigerator 1 is improved by considering the characteristics of each evaporator.

[0035] FIG. 7 is a cross-sectional view of a heat transfer tube of an evaporator of the refrigerator according to the first embodiment, where a shows a cross-sectional view of a heat transfer tube of the first evaporator 15a, and b shows a cross-sectional view of a heat transfer tube of the second evaporator 15b. As shown in FIG. 7, the inner surface of the heat transfer tube 32 of the first evaporator 15a is grooved to increase the heat transfer area on the refrigerant side, thereby making the temperature of the heat transfer tube 32 as close as possible to the refrigerant temperature, thereby improving the cooling efficiency. On the other hand, the inner surface of the heat transfer tube 32 of the second evaporator 15b is smooth to make the temperature of the heat transfer tube 32 higher than the refrigerant temperature, thereby reducing the amount of frost formation and shortening the defrosting time. In this way, on the first evaporator 15a side, the temperature difference between the air and the refrigerant is small (about 5° C.) and the growth rate of frost is slow, so that the temperature difference between the refrigerant and the heat transfer tube 32 is made as small as possible to easily improve the cooling efficiency. On the other hand, on the second evaporator 15b side, the temperature difference between the air and the refrigerant is large (about 25°C) and frost grows quickly, so the temperature difference between the refrigerant and the heat transfer tube 32 is made as large as possible to suppress the growth of frost.

[0036] Fig. 8 is a layout diagram of the refrigeration cycle components of the refrigerator according to the first embodiment, seen from the front. As shown in Fig. 8, the compressor 25 and the first radiator 26a are provided in the machine room 24, the second radiator 26b is provided on a side surface of the refrigerator 1, the first evaporator 15a is provided in the freezing temperature zone room 7 (on the rear side thereof), and the second evaporator 15b is provided in the refrigeration room 2 (on the rear side thereof). In addition, the refrigerant pipe 31 connecting the second evaporator 15b and the first evaporator 15a is arranged to extend downward from the second evaporator 15b. Furthermore, the heat transfer tube 32 of the second evaporator 15b is configured to descend monotonically.

[0037] Here, it is assumed that the liquid refrigerant flows from the vertically upper side to the vertically lower side through the heat transfer tube 32 of the second evaporator 15b while the compressor 25 is in operation, and the heat transfer tube 32 is expressed as "descending" monotonically. However, if the liquid refrigerant flows from the vertically lower side to the vertically upper side through the heat transfer tube 32 of the second evaporator 15b while the compressor 25 is in operation, the heat transfer tube 32 can also be interpreted as "rising" monotonically. In any case, it is sufficient that the heat transfer tube 32 of the second evaporator 15b is disposed with a continuous incline so that the liquid refrigerant in the heat transfer tube 32 continues to descend by gravity while the compressor 25 is stopped. Therefore, even if there is a slight horizontal or upward incline in parts, it is permissible as long as the liquid refrigerant is discharged by gravity.

[0038] As a result, during off-cycle operation, the liquid refrigerant in the second evaporator 15b decreases due to gravity, reducing the thermal load for melting the frost and improving the defrosting efficiency (off-cycle operation efficiency) of the refrigerator compartment 2. In addition, the frost in the second evaporator 15b is melted and air containing moisture is supplied to the refrigerator compartment 2, increasing the humidity in the refrigerator compartment 2 and improving the freshness of refrigerated foods.

[0039] As shown in FIG. 8, the second evaporator 15b is provided above the first evaporator 15a, thereby suppressing the flow of liquid refrigerant from the first evaporator 15a to the second evaporator 15b during off-cycle operation, suppressing an increase in heat load, and improving defrosting efficiency (efficiency of off-cycle operation). Furthermore, in this embodiment, the second evaporator 15b and the first evaporator 15a are connected in series by the refrigerant pipe 31 extending downward from the second evaporator 15b, so that the first evaporator 15a plays the role of a tank (reservoir) that collects the liquid refrigerant that has flowed down from the second evaporator 15b. Therefore, the liquid refrigerant is reliably discharged from the heat transfer tube 32 of the second evaporator 15b, which results in further improvement of the defrosting efficiency. Note that the tank that collects the liquid refrigerant may be anything other than the first evaporator 15a as long as it has a cross-sectional area larger than that of the heat transfer tube 32, and may be, for example, a header that is separately provided at a position lower than the second evaporator 15b.

[0040] In this embodiment, not only the first evaporator 15a but also the second evaporator 15b is provided in the refrigerator compartment 2. As a result, the amount of frost on the first evaporator 15a is reduced compared to the case where only the first evaporator 15a is provided, the defrosting operation time of the freezing temperature zone compartment 7 is reduced, and the energy saving performance of the refrigerator 1 can be improved. Note that in this embodiment, frost grows on the second evaporator 15b and is melted by off-cycle operation, but compared to the increase in power consumption due to the off-cycle operation, the reduction in the defrosting time of the freezing temperature zone compartment 7 has a greater impact, and the power consumption of the refrigerator 1 can be reduced.

[0041] In addition, by connecting the first evaporator 15a and the second evaporator 15b in series as in this embodiment, the number of capillary tubes 28 is reduced from two to one compared to the case of connecting them in parallel, and components such as a valve for branching the refrigerant flow path and a check valve for suppressing the backflow of the refrigerant are not required. As a result, the refrigerator 1 can be manufactured at low cost, and the rate of manufacturing defects can be reduced because the refrigeration cycle structure is simple. Furthermore, in this embodiment, the refrigerant is configured to pass through the first evaporator 15a and the gas-liquid separator 30 after passing through the second evaporator 15b, and the gas-liquid separator 30 is mounted in the freezer compartment cold air duct 18. With this configuration, it is not necessary to mount the gas-liquid separator 30 inside the wall surface of the heat-insulating box 9, so that it is possible to achieve both a thin heat-insulating box 9 and improved defrosting efficiency.

[0042] Similarly, by configuring the second evaporator 15b on the upstream side of the refrigerant and the first evaporator 15a on the downstream side of the refrigerant, the refrigerant temperature of the first evaporator 15a is lower than that of the second evaporator 15b due to pressure loss in the heat transfer tube. Furthermore, the amount of liquid refrigerant is less on the downstream side of the refrigerant (the drier degree is higher), so the heat transfer coefficient on the refrigerant side is improved. Therefore, on the first evaporator 15a side, the temperature difference between the air and the refrigerant is made as large as possible, making it easy to increase the cooling efficiency, and on the second evaporator 15b side, the temperature difference between the air and the refrigerant is made as small as possible, making it easy to suppress the growth of frost and making it highly efficient in defrosting. EXAMPLES

[0043] Next, a refrigerator 1 according to a second embodiment of the present invention will be described with reference to Figs. 9 and 10. The refrigerator 1 according to the second embodiment has only a refrigerator compartment as a storage compartment, and the refrigerator compartment is cooled by one evaporator 15c. Other configurations are similar, and therefore repeated explanations will be omitted.

[0044] Fig. 9 is a configuration diagram of a refrigeration cycle of a refrigerator according to Example 2. As shown in Fig. 9, a refrigerator 1 according to this embodiment includes a compressor 25, a first radiator 26a and a second radiator 26b as heat dissipation means for dissipating heat from a refrigerant, a capillary tube 28 as a pressure reducing means for reducing the pressure of the refrigerant, and an evaporator 15c (refrigerating evaporator) for absorbing heat inside the refrigerator by heat exchange between the refrigerant and the air inside the refrigerator. The refrigerator 1 further includes a dryer 29 for removing moisture in the refrigeration cycle, and these are connected by a refrigerant pipe 31 to form a refrigeration cycle.

[0045] FIG. 10 is a layout diagram of the refrigeration cycle components of the refrigerator according to the second embodiment, seen from the front. As shown in FIG. 10, the compressor 25 and the first radiator 26a are provided in the machine room 24, the second radiator is provided on the side of the refrigerator 1, and the evaporator 15c is provided on the back side of the refrigerator 2. The heat transfer tube 32 of the evaporator 15c is configured to descend monotonically, and the refrigerant piping connecting the evaporator 15c and the compressor 25 is arranged to extend downward from the evaporator 15c. Therefore, as in the first embodiment, the liquid refrigerant in the evaporator 15c decreases due to gravity during the off-cycle operation, so that the heat load for melting the frost is reduced, and the defrosting efficiency of the refrigerator compartment 2 can be improved. In addition, the frost on the evaporator 15c is melted and the air containing moisture is supplied to the refrigerator compartment 2, so that the refrigerator compartment 2 can be made highly humid, improving the freshness of refrigerated foods. In this embodiment, the compressor 25 serves as a tank (storage section) that collects the liquid refrigerant that has flowed down from the evaporator 15c, and the liquid refrigerant is reliably discharged from the heat transfer tube 32 of the evaporator 15c, which leads to further improvement in defrosting efficiency.

[0046] The above is the form of this embodiment. Note that the present invention is not limited to the above-mentioned form, and various modified examples are included. For example, the above-mentioned embodiment has been described in detail to explain the present invention in an easy-to-understand manner, and is not necessarily limited to an embodiment having all of the configurations described. Furthermore, it is possible to add, delete, or replace part of the configuration of the embodiment with other configurations. [Explanation of symbols]

[0047] 1. Refrigerator 2. Refrigerator compartment 3. Ice making room 4. Upper freezer compartment 5 Lower freezer 6. Vegetable compartment 7 Freezing temperature room 8. Ice greenhouse 9. Insulated box 10. Vacuum insulation material 11. Insulated partition wall 12 Partition cover 13 Door pocket 14. Shelf 15a First evaporator 15b Second evaporator 15c Evaporator 16a... First blower 16b...Second blower 16c... Blower 17... Refrigerator cold air duct 18 Freezer cold air duct 20 Refrigerator damper 21 Baffle plate 22 Radiant heater 23 Control board 24... Machine room 25... Compressor 26a... First heat sink 26b...Second radiator 27... External blower 28... Capillary tube 29. Dryer 30... Gas-liquid separator 31... Refrigerant piping 32... Heat transfer tube 33... Cooling surface 34. Fin

Claims

1. the cooling system comprises an insulated box having an insulating material provided between an inner box and an outer box, a refrigeration temperature zone chamber formed within the insulated box, a refrigeration evaporator for cooling the refrigeration temperature zone chamber, a second blower for blowing cold air cooled by the refrigeration evaporator into the refrigeration temperature zone chamber, a freezing temperature zone chamber formed within the insulated box, a freezing evaporator for cooling the freezing temperature zone chamber, a first blower for blowing cold air cooled by the freezing evaporator into the freezing temperature zone chamber, and a compressor for compressing a refrigerant, The refrigerant discharged from the compressor flows through a radiator and a pressure reducing means, passes through the refrigeration evaporator, and then flows into the freezing evaporator; A refrigerator in which the second blower is operated while the compressor is stopped to defrost the refrigeration evaporator, During defrosting of the refrigeration evaporator by stopping the compressor and operating the second blower, liquid refrigerant in the refrigeration evaporator is discharged by gravity, and the discharged liquid refrigerant flows into the freezing evaporator that is connected in series below the refrigeration evaporator on the refrigerant downstream side of the refrigeration evaporator, and the freezing evaporator serves as a storage section that stores the liquid refrigerant.

2. In the refrigerator according to claim 1, A refrigerator in which the heat transfer tube constituting the refrigeration evaporator is arranged at a continuous incline so that the liquid refrigerant in the heat transfer tube continues to descend due to gravity.

3. In the refrigerator according to claim 1, The heat transfer tube constituting the refrigeration evaporator is disposed in a space between the inner box and the refrigeration temperature zone chamber, A refrigerator in which a heat transfer tube constituting the refrigeration evaporator is disposed within a foam insulation material between the inner box and the outer box.

4. In the refrigerator according to claim 3, The heat transfer tube constituting the refrigeration evaporator has a grooved inner surface, The heat transfer tube constituting the refrigeration evaporator has a smooth inner surface.

5. In the refrigerator according to claim 1, A heat transfer tube constituting the refrigeration evaporator is in contact with the inner box and cools the refrigeration temperature zone compartment via a cooling surface provided on the refrigeration temperature zone compartment side of the inner box.

6. The refrigerator according to claim 5, The refrigerator has resin fins provided on the cooling surface.

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