JP7636969B2 - refrigerator - Google Patents

Description

The present invention relates to a refrigerator.

A refrigerator has an insulated box body with a storage compartment and an insulated door that opens and closes the storage compartment, and cools the air in the storage compartment using a refrigeration cycle consisting of a compressor, a condenser, a pressure reducing means, and an evaporator. In addition, since frost grows on the cooler, a defrosting operation is periodically performed.

During defrosting operation of such refrigerators, the amount of liquid refrigerant inside the evaporator is controlled to reduce the heat load for defrosting and improve the defrosting efficiency. For example, Patent Document 1 states that "In a refrigerator equipped with a freezer compartment, a freezer evaporator for cooling the freezer compartment, a refrigerator compartment provided below the freezer compartment, and a freezer evaporator for cooling the refrigerator compartment, a compressor, a radiator, a pressure reducing means, the freezer evaporator for freezing, and the freezer evaporator for freezing are connected by refrigerant piping, and the refrigerator has a refrigeration cycle in which the refrigerator for freezing and the evaporator for freezing are connected in series, and a refrigerant circulation suppression means is provided in the piping connecting the refrigerator for freezing and the evaporator for freezing to suppress refrigerant circulation when the compressor is stopped."

Patent document 2 states 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."

JP 2018-204874 A JP 2002-71262 A

The refrigerator disclosed in Patent Document 1 suppresses heat transfer between evaporators while the compressor is stopped, improving energy saving performance. However, the refrigerator described in Patent Document 1 has an issue in that liquid refrigerant remains in the refrigeration evaporator when defrosting operation starts for a refrigerator compartment that requires frequent defrosting operation, and energy is required to evaporate the liquid refrigerant to melt the frost.

In the refrigerator disclosed in Patent Document 2, the amount of refrigerant in the evaporator that is defrosted is reduced by recovering the refrigerant, thereby improving the defrosting efficiency. However, the refrigerator described in Patent Document 2 has a problem in that the compressor needs to be operated for several minutes to recover the refrigerant, which reduces the energy saving performance.

The object of the present invention is to improve the defrosting efficiency of a refrigeration evaporator and provide a refrigerator with high energy-saving performance.

In order to solve these problems, the present invention provides a refrigerator that includes an insulated box with an insulating material between an inner box and an outer box, a refrigeration temperature zone compartment formed within the insulated box, a refrigeration evaporator that cools the refrigeration temperature zone compartment, a blower that blows the cold air cooled by the refrigeration evaporator to the refrigeration temperature zone compartment, and a compressor that compresses a refrigerant, and that defrosts the refrigeration evaporator by operating the blower while the compressor is stopped, and is characterized in that liquid refrigerant in the refrigeration evaporator is discharged by gravity while the compressor is stopped.

According to the present invention, the liquid refrigerant in the refrigeration evaporator can be reduced without the power of a compressor, improving the defrosting efficiency of the refrigeration evaporator and providing a refrigerator with high energy-saving performance.

FIG. 1 is a front view of a refrigerator according to a first embodiment. 2 is a cross-sectional view taken along line AA of FIG. 1. FIG. 1 is a configuration diagram of a refrigeration cycle of a refrigerator according to a first embodiment. FIG. 2 is a perspective view of a freezing evaporator of the refrigerator according to the first embodiment. FIG. 2 is a side view of a refrigeration evaporator of the refrigerator according to the first embodiment. FIG. 2 is a perspective view of a cooling surface of a second evaporator of the refrigerator according to the first embodiment. FIG. 2 is a cross-sectional view of a heat transfer tube of an evaporator of the refrigerator according to the first embodiment. FIG. 2 is a front view showing the layout of refrigeration cycle components of the refrigerator according to the first embodiment. FIG. 11 is a configuration diagram of a refrigeration cycle of a refrigerator according to a second embodiment. FIG. 11 is a front view showing the layout of refrigeration cycle components of a refrigerator according to a second embodiment.

The following describes in detail an embodiment of the present invention, with reference to the drawings as appropriate.

The refrigerator 1 according to the first embodiment of the present invention will be described with reference to Figs. 1 to 8.

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

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 each have 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.

Figure 2 is a cross-sectional view taken along the line A-A in Figure 1. The outside and inside of the refrigerator 1 are separated by an insulated 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 installed 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.

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 number of door pockets 13 are provided on the inside of the refrigerator compartment door 2a, and multiple shelves 14 are provided in the refrigerator compartment 2, dividing the compartment into a number of storage spaces.

The upper freezer compartment 4, the lower freezer compartment 5, and the vegetable compartment 6 are each provided with a storage container 4b, 5b, or 6b that moves together with the door at the front of each compartment, and the storage containers 4b, 5b, or 6b can be pulled out by pulling the door out towards the front. 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 be pulled out by pulling the door out towards the front.

Above the insulating partition wall 11a, there is an ice temperature chamber 8 which is set to a temperature lower than the temperature range of the refrigerator chamber 2. The ice temperature chamber 8 can be switched between a refrigeration temperature range mode, for example, about 0 to 4°C, and a freezing temperature range mode, for example, about -3 to 0°C, by, for example, controlling the second evaporator 15b and the second blower 16b, and a heater (not shown) provided inside the insulating partition wall 11a.

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 refrigeration 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 through the refrigerator compartment cold air duct 17, the freezer compartment cold air duct 18, and the vegetable compartment cold air duct (not shown) 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. 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.

The blowing of cold air into 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 a 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.

The blowing of cool air into the vegetable compartment 6 is controlled by opening and closing the 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 to adjust the amount of blown air. The air sent to the vegetable compartment 6 can be continuously cooled by returning below the first evaporator 15a.

A radiant heater 22 is provided below the first evaporator 15a. If 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.

The second evaporator 15b (refrigeration evaporator) 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 the 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).

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, in this embodiment, the refrigerator compartment 2 is cooled by the second evaporator 15b when the heat load is not large. In other words, since the low-humidity cold air that has exchanged heat with the first evaporator 15a does not flow directly into the refrigerator compartment 2, it is possible to keep the refrigerator compartment 2 in a high humidity state.

The 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 non-steady 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 melted frost can be used to increase the humidity of the refrigerator compartment 2. Hereinafter, the operation of defrosting and cooling the refrigerator compartment 2 by operating the second blower 16b while the compressor 25 is stopped will be referred to as off-cycle operation.

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

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 in the machine room 24 located below the refrigerator 1.

Figure 3 is a schematic diagram of the refrigeration cycle of the refrigerator according to the first embodiment. As shown in Figure 3, the refrigerator 1 of this embodiment includes a compressor 25 that compresses the refrigerant, a first radiator 26a and a second radiator 26b that are heat dissipation means that dissipate heat from the refrigerant, a capillary tube 28 that is a pressure reduction means that reduces the pressure of the refrigerant, and a first evaporator 15a and a second evaporator 15b that absorb heat from the inside of the refrigerator by exchanging heat between the refrigerant and the air inside the refrigerator. The refrigerator 1 also includes a dryer 29 that removes moisture in the refrigeration cycle and a gas-liquid separator 30 that prevents liquid refrigerant from flowing into the compressor 25, and these are connected by a refrigerant pipe 31 to form a refrigeration cycle.

The first radiator 26a is configured to have a higher heat dissipation efficiency than the second radiator 26b because it draws in outside air using the outside air blower 27. The refrigerator 1 of this embodiment uses isobutane as a refrigerant. The compressor 25 of this embodiment is equipped 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.

Figure 4 is a perspective view of the first evaporator of the refrigerator according to the first embodiment. As shown in Figure 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 passes through multiple 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 the space between the inner box 9b and the freezing temperature zone compartment 7.

Figure 5 is a side view of the second evaporator of the refrigerator according to the first embodiment. As shown in Figure 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 insulated box 9. The heat transfer tube 32 is bent multiple times and disposed in the foam insulation material between the outer box 9a and the inner box 9b, and is in contact with 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 insulated box 9, the cooling system is made smaller and the food storage volume is expanded. In addition, the back surface of the second evaporator 15b is provided with a vacuum insulation material 10 to suppress heat absorption from the outside of the refrigerator.

Figure 6 is a perspective view of the cooling surface of the second evaporator of the refrigerator according to the first embodiment. As shown in Figure 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 air resistance can be suppressed. In addition, by making the fins 34 from a resin material, the cooling surface temperature is higher than when the fins 34 are made of metal, so the amount of frost formation on the second evaporator 15b is suppressed, and the off-cycle operation time can be shortened. In addition, by suppressing the amount of frost formation, the 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 make the cooling surface 33 from resin. 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 fins 34 are made of resin to suppress the amount of frost, but if priority is given to the cooling performance of the refrigerator compartment 2, they can also be made of metal such as aluminum.

As described above with reference to FIG. 5 and FIG. 6, the first evaporator 15a has a cross-fin tube type configuration that makes it easy to 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 frost growth rate is slow, so improving cooling efficiency is prioritized over suppressing 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 frost growth rate is fast, so suppressing 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.

7 is a cross-sectional view of the heat transfer tube of the evaporator of the refrigerator according to the first embodiment, where a is a cross-sectional view of the heat transfer tube of the first evaporator 15a, and b is a cross-sectional view of the 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, so that the temperature of the heat transfer tube 32 is 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, so that the temperature of the heat transfer tube 32 is higher than the refrigerant temperature, thereby suppressing 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 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 frost growth.

Figure 8 is a front view of the refrigeration cycle components of the refrigerator according to the first embodiment. As shown in Figure 8, the compressor 25 and the first radiator 26a are provided in the machine room 24, the second radiator 26b is provided on the side of the refrigerator 1, the first evaporator 15a is provided in the freezing temperature zone room 7 (on the rear side), and the second evaporator 15b is provided in the refrigerator room 2 (on the rear side). 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.

Here, it is assumed that liquid refrigerant flows from vertically above to vertically below the heat transfer tube 32 of the second evaporator 15b while the compressor 25 is running, and the heat transfer tube 32 is described as "descending" monotonically. However, if liquid refrigerant flows from vertically below to vertically above the heat transfer tube 32 of the second evaporator 15b while the compressor 25 is running, 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 arranged with a continuous incline so that the liquid refrigerant in the heat transfer tube 32 continues to descend due to gravity while the compressor 25 is stopped. Therefore, even if there are some horizontal or upward inclines, this is acceptable as long as the liquid refrigerant is discharged by gravity.

As a result, during off-cycle operation, the liquid refrigerant in the second evaporator 15b is reduced by gravity, reducing the thermal load required to melt 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.

As shown in FIG. 8, the second evaporator 15b is provided above the first evaporator 15a to suppress 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 serves as a tank (reservoir) for storing the liquid refrigerant that has flowed down from the second evaporator 15b. As a result, 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 for storing the liquid refrigerant may be anything other than the first evaporator 15a as long as it has a larger cross-sectional area than the heat transfer tube 32, and may be, for example, a header separately provided at a position lower than the second evaporator 15b.

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 when 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. In this embodiment, frost grows on the second evaporator 15b and is melted by off-cycle operation, but the impact of shortening the defrosting time of the freezing temperature zone compartment 7 is greater than the increase in power consumption due to off-cycle operation, and the power consumption of the refrigerator 1 can be reduced.

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 can be reduced from two to one compared to the case of connecting them in parallel, and parts such as a valve for branching the refrigerant flow path and a check valve for suppressing backflow of the refrigerant are also unnecessary. 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 cold air duct 18. With this configuration, it is not necessary to mount the gas-liquid separator 30 inside the wall surface of the thermal insulation box 9, so that it is possible to achieve both a thin thermal insulation box 9 and improved defrosting efficiency.

Similarly, by using 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 (higher dryness), improving the heat transfer coefficient on the refrigerant side. Therefore, on the first evaporator 15a side, the temperature difference between the air and the refrigerant is maximized, making it easy to increase cooling efficiency, while on the second evaporator 15b side, the temperature difference between the air and the refrigerant is minimized, making it easy to suppress frost growth and making it highly efficient at defrosting.

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 this refrigerator compartment is cooled by a single evaporator 15c. The rest of the configuration is similar, and therefore a duplicated description will be omitted.

Figure 9 is a schematic diagram of the refrigeration cycle of a refrigerator according to Example 2. As shown in Figure 9, the refrigerator 1 of this embodiment includes a compressor 25, a first radiator 26a and a second radiator 26b that are heat dissipation means for dissipating heat from the refrigerant, a capillary tube 28 that is a pressure reduction means for reducing the pressure of the refrigerant, and an evaporator 15c (refrigerating evaporator) that absorbs heat inside the refrigerator by exchanging heat between the refrigerant and the air inside the refrigerator. The refrigerator 1 also includes a dryer 29 that removes moisture in the refrigeration cycle, and these are connected by a refrigerant pipe 31 to form a refrigeration cycle.

Figure 10 is a front view of the refrigeration cycle components of the refrigerator according to the second embodiment. As shown in Figure 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 off-cycle operation, so that the heat load for melting the frost is reduced, and the defrosting efficiency of the refrigerator chamber 2 can be improved. In addition, the frost on the evaporator 15c is melted and the air containing moisture is supplied to the refrigerator chamber 2, so that the refrigerator chamber 2 can be made highly humid, improving the freshness of refrigerated foods. In this embodiment, the compressor 25 serves as a tank (reservoir) 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, leading to further improvements in defrosting efficiency.

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 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.

REFRIGERATION COMPARTMENT 1 Refrigerator 2 Refrigeration compartment 3 Ice making compartment 4 Upper freezer compartment 5 Lower freezer compartment 6 Vegetable compartment 7 Freezing temperature zone compartment 8 Ice temperature compartment 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 Refrigeration compartment cold air duct 18 Freezer compartment cold air duct 20 Refrigeration compartment damper 21 Baffle plate 22 Radiant heater 23 Control board 24 Machinery compartment 25 Compressor 26a First radiator 26b Second radiator 27 External blower 28 Capillary tube 29... Dryer 30... Gas-liquid separator 31... Refrigerant pipe 32... Heat transfer tube 33... Cooling surface 34... Fin

Claims (6)

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

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