JP6872689B2 - refrigerator - Google Patents

Description

The present invention relates to a refrigerator that reduces the output of a defrost heater.

From the viewpoint of energy saving, in household refrigerators, the high-pressure refrigerant in the refrigeration cycle flows into the evaporator due to the pressure difference and uses the energy to heat the evaporator to reduce the output of the electric heater for defrosting. There is. This is because the high-pressure refrigerant stored inside the condenser in the refrigeration cycle is maintained near the outside air temperature even after the compressor is stopped, while the evaporator is in a low temperature state of -30 to -20 ° C. By increasing the amount of heat flowing into the evaporator due to the pressure difference, or by increasing the enthalpy of the inflowing high-pressure refrigerant to increase the amount of heat flowing in, the output of the defrosting electric heater is positively reduced to save energy. It is intended.

Hereinafter, a conventional refrigerator will be described with reference to the drawings.

FIG. 6 is a vertical cross-sectional view of a conventional refrigerator, FIG. 7 is a refrigerating cycle configuration diagram of the conventional refrigerator, and FIG. 8 is a diagram showing control during defrosting of the conventional refrigerator.

In FIGS. 6 and 7, the refrigerator 11 includes a housing 12, a door 13, legs 14 that support the housing 12, a lower machine room 15 provided at the bottom of the housing 12, and refrigeration arranged above the housing 12. It has a freezing room 18 arranged at the bottom of the room 17 and the housing 12. Further, as parts constituting the refrigerating cycle, a compressor 56 housed in the lower machine room 15, an evaporator 20 housed on the back side of the freezing room 18, and a main condenser 21 housed in the lower machine room 15 are included. Have. Further, it has a partition wall 22 for partitioning the lower machine room 15, a fan 23 attached to the partition wall 22 for air-cooling the main condenser 21, an evaporating dish 57 installed above the compressor 56, and a bottom plate 25 for the lower machine room 15. There is.

Further, a plurality of intake ports 26 provided on the bottom plate 25, a discharge port 27 provided on the back side of the lower machine room 15, and a communication air passage 28 connecting the discharge port 27 of the lower machine room 15 and the upper part of the housing 12 are provided. Have. Here, the lower machine room 15 is divided into two chambers by a partition wall 22, and the main condenser 21 is housed on the leeward side of the fan 23, and the compressor 56 and the evaporating dish 57 are housed on the leeward side.

Further, as a component constituting the refrigeration cycle, the dew-proof pipe 60 and the dew-proof pipe 60 located on the downstream side of the main condenser 21 and thermally coupled to the outer surface of the housing 12 around the opening of the freezing chamber 18 It is located on the downstream side and has a dryer 137 that dries the circulating refrigerant, and a throttle 45 that combines the dryer 137 and the evaporator 20 to reduce the pressure of the circulating refrigerant. Then, when the evaporator 20 is defrosted, it has a two-way valve 61 that closes the outlet of the dew-proof pipe 60, and a defrost heater (not shown) that heats the evaporator 20.

Further, the evaporator fan 50 that supplies the cold air generated by the evaporator 20 to the refrigerating chamber 17 and the freezing chamber 18, the freezing chamber damper 51 that shuts off the cold air supplied to the freezing chamber 18, and the cold air supplied to the refrigerating chamber 17 The temperature of the refrigerating chamber damper 52 that shuts off, the duct 53 that supplies cold air to the refrigerating chamber 17, the FCC temperature sensor 54 that detects the temperature of the refrigerating chamber 18, the PCC temperature sensor 55 that detects the temperature of the refrigerating chamber 17, and the temperature of the evaporator 20. It has a DEF temperature sensor 58 to detect.

The operation of the conventional refrigerator configured as described above will be described below.

In the cooling stop state (hereinafter, this operation is referred to as "OFF mode") in which the fan 23, the compressor 56, and the evaporator fan 50 are all stopped, the temperature detected by the FCC temperature sensor 54 rises to a predetermined value of the FCC_ON temperature. Or, when the temperature detected by the PCC temperature sensor 55 rises to the predetermined PCC_ON temperature, the freezer compartment damper 51 is closed, the refrigerating chamber damper 52 is opened, and the compressor 56, the fan 23, and the evaporator fan 50 are opened. (Hereinafter, this operation is referred to as "PC cooling mode").

In the PC cooling mode, by driving the fan 23, the main condenser 21 side of the lower machine room 15 partitioned by the partition wall 22 becomes a negative pressure, and external air is sucked from a plurality of intake ports 26, and the compressor 56 and the evaporating dish are sucked. The pressure on the 57 side becomes positive, and the air in the lower machine room 15 is discharged to the outside from the plurality of discharge ports 27.

On the other hand, the refrigerant discharged from the compressor 56 is condensed by leaving a part of the gas while exchanging heat with the outside air in the main condenser 21, and then supplied to the dew-proof pipe 60. The refrigerant passing through the dew-proof pipe 60 dissipates heat and condenses through the housing 12 while warming the opening of the freezing chamber 18. After passing through the two-way valve 61, the liquid refrigerant condensed by the dew-proof pipe 60 is water-removed by the dryer 137, depressurized by the throttle 45, and evaporates by the evaporator 20 while exchanging heat with the air inside the refrigerator compartment 17. While cooling the refrigerating chamber 17, it is returned to the compressor 56 as a gaseous refrigerant.

During the PC cooling mode, when the temperature detected by the FCC temperature sensor 54 drops and rises to the predetermined value of FCC_OFF temperature and the temperature detected by the PCC temperature sensor 55 drops to the predetermined value of PCC_OFF temperature, the mode shifts to the OFF mode.

Further, during the PC cooling mode, when the temperature detected by the FCC temperature sensor 54 indicates a temperature higher than the predetermined value of the FCC_OFF temperature and the temperature detected by the PCC temperature sensor 55 drops to the predetermined value of the PCC_OFF temperature, the freezer compartment damper 51 is opened, the refrigerator damper 52 is closed, and the compressor 56, the fan 23, and the evaporator fan 50 are driven. Hereinafter, by operating the refrigerating cycle in the same manner as the PC cooling, the refrigerator 20 is cooled by exchanging heat between the air inside the refrigerating chamber 18 and the evaporator 20 (hereinafter, this operation is referred to as “FC cooling mode”). ..

During the FC cooling mode, when the temperature detected by the FCC temperature sensor 54 drops to the predetermined value of FCC_OFF temperature and the temperature detected by the PCC temperature sensor 55 indicates the predetermined value of PCC_ON temperature or higher, the mode shifts to the PC cooling mode. ..

Further, during the FC cooling mode, when the temperature detected by the FCC temperature sensor 54 drops to the FCC_OFF temperature of a predetermined value and the temperature detected by the PCC temperature sensor 55 indicates a temperature lower than the PCC_ON temperature of the predetermined value, the OFF mode is used. Transition to.

Here, the control at the time of defrosting of the conventional refrigerator will be described with reference to FIG.

When the cumulative operating time of the compressor 56 reaches a predetermined time, the mode shifts to the defrosting mode in which the frost adhering to the evaporator 20 is heated and melted. In the defrosting mode section p, first, in order to suppress the temperature rise of the freezing chamber 18, the freezing chamber 18 is cooled for a predetermined time in the same manner as in the FC cooling mode. Next, in the section q, the refrigerant staying in the dryer 137 and the evaporator 20 is recovered to the main condenser 21 and the dew-proof pipe 60 by closing the two-way valve 61 while operating the compressor 56. Then, in the section r, the main condenser 21 and the dew-proof pipe 60 are connected to the main condenser 21 and the dew-proof pipe 60 via a seal portion such as a valve (not shown) that separates the high-pressure side and the low-pressure side inside the compressor 56 by stopping the compressor 56. By flowing the recovered high-pressure refrigerant back into the evaporator 20, the evaporator 20 is heated by using the high-pressure refrigerant further heated by the waste heat of the compressor 56. Then, in the section s, the defrost heater (not shown) attached to the evaporator 20 is energized to complete the defrosting when the DEF temperature sensor 58 reaches a predetermined temperature. Then, in the section t, the two-way valve 61 is opened to equalize the pressure in the refrigeration cycle, and the normal operation is restarted from the section u.

By the operation described above, the electric power of the defrost heater can be reduced by heating the evaporator by using the high-pressure refrigerant of the refrigeration cycle and the waste heat of the compressor, and the energy saving of the refrigerator can be achieved. Can be planned.

Japanese Unexamined Patent Publication No. 4-194564

However, in the conventional refrigerator configuration, when the high-pressure refrigerant recovered in the main condenser 21 and the dew-proof pipe 60 is used for defrosting the evaporator 20, the prevention is thermally coupled to the periphery of the opening of the freezer chamber 18. The temperature of the dew pipe 60 drops, and the high-pressure refrigerant in the main condenser 21 maintained at substantially the outside air temperature condenses inside the dew pipe 60. As a result, the high-pressure pressure drops and the amount of refrigerant flowing into the evaporator 20 decreases, which causes the power amount of the defrost heater to be unable to be sufficiently reduced.

Therefore, it has been a problem to maintain the high pressure when the recovered high pressure refrigerant is used for defrosting the evaporator 20.

Further, in the conventional refrigerator configuration, even if the compressor 56 is operated when recovering the refrigerant, the temperature of the evaporator is too low, so that sufficient refrigerant recovery cannot be performed.

Therefore, when the recovered high-pressure refrigerant is used for defrosting the evaporator 20, the amount of the high-pressure refrigerant flowing into the evaporator 20 is small and the temperature rise of the evaporator 20 is small, so that the electric energy of the defrost heater is sufficient. The problem was that it could not be reduced.

Further, in order to increase the amount of the high-pressure refrigerant flowing into the evaporator 20 as much as possible, the temperature around the evaporator is low even if the refrigerant recovery time is lengthened, so that the refrigerant easily stays in the evaporator and is recovered. The time will be longer. The longer recovery time means that the entire defrosting time for energizing the heater to raise the evaporator temperature to a predetermined temperature becomes longer, that is, the non-cooling time inside the refrigerator becomes longer, so the temperature inside the refrigerator tends to rise. .. Therefore, there is a problem that not only the cooling operation time after defrosting is long, but also the temperature of the stored food rises and the freshness deteriorates.

The present invention solves the conventional problems, and when the recovered high-pressure refrigerant is used for defrosting the evaporator, the recovery time of the refrigerant is shortened while suppressing an excessive decrease in the evaporator temperature, and the recovery time of the refrigerant is shortened. The purpose is to improve energy saving by shortening the defrosting time and improve food retention by suppressing the temperature rise inside the refrigerator.

In order to solve the conventional problems, the refrigerator of the present invention includes a refrigerating cycle having at least a compressor, an evaporator, a main condenser, and a dew-proof pipe, and a flow path switching valve connected to the downstream side of the main condenser. And a dew-proof pipe connected to the downstream side of the flow path switching valve, and a bypass path having a heat exchange portion connected in parallel with the dew-proof pipe and partially thermally coupled to the compressor to insulate. In a refrigerator equipped with a freezer compartment damper and a refrigerating chamber damper that control the cold air supplied to the freezer compartment and the refrigerator compartment formed by walls, respectively, when the evaporator is defrosted, it is provided in the vicinity of the evaporator. While the evaporator fan and the compressor are in operation, the flow path switching valve is fully closed, the refrigerator compartment damper is opened, and the freezer compartment damper is closed. After the recovery operation, the compressor is stopped and the flow path switching valve is opened to the bypass path side to supply the recovered high-pressure refrigerant to the evaporator, and after a predetermined time, it is provided in the vicinity of the evaporator. It energizes the defrost heater.

As a result, a sufficient amount of refrigerant can be recovered without the evaporator temperature dropping too much at the time of refrigerant recovery, and the recovery time can be shortened. Therefore, the entire defrosting time, that is, the non-cooling time is shortened, and only the power consumption is reduced. However, the temperature rise of the food itself stored in the refrigerator is also reduced. Further, when the recovered high-pressure refrigerant is used for defrosting the evaporator, the amount of electric power of the defrost heater can be stably reduced by suppressing the fluctuation of the high-pressure pressure.

In addition, when the recovered high-pressure refrigerant is used for defrosting the evaporator, it is supplied to the evaporator via the bypass path, and the bypass path and the compressor are thermally coupled, so that the high-pressure refrigerant is used in the evaporator. By recovering the waste heat of the compressor at the time of supply and using it for heating the evaporator, the electric energy of the defrost heater can be further reduced.

In the refrigerator of the present invention, the amount of power of the defrost heater can be stably reduced by collecting the refrigerant in the refrigeration cycle in the main condenser and using it for heating the evaporator, which saves energy in the refrigerator. Can be planned.

Longitudinal sectional view of the refrigerator according to the first embodiment of the present invention. Cycle configuration diagram of the refrigerator according to the first embodiment of the present invention (A) Enlarged schematic view of the main part of the heat exchange part with the compressor of the refrigerator in the first embodiment of the present invention (b) Schematic diagram of the cross section of the main part. Configuration diagram of the cooling chamber of the refrigerator according to the first embodiment of the present invention. The figure which showed the control at the time of defrosting of the refrigerator in Embodiment 1 of this invention. Longitudinal section of a conventional refrigerator Cycle configuration diagram of a conventional refrigerator The figure which showed the control at the time of defrosting of the conventional refrigerator

The first invention comprises a refrigerating cycle having at least a compressor, an evaporator, a main condenser, and a dew-proof pipe, and a flow path switching valve connected to the downstream side of the main condenser and a flow path switching valve downstream of the flow path switching valve. A freezer compartment having a dew-proof pipe connected to the side and a bypass path having a heat exchange part connected in parallel with the dew-proof pipe and partially thermally coupled with a compressor, and a freezer compartment formed by a heat insulating wall. In a refrigerator equipped with a freezer compartment damper and a refrigerator compartment damper that control the cold air supplied to the refrigerator compartment, when defrosting the evaporator, an evaporator fan and a compressor provided in the vicinity of the evaporator are used. During operation, the flow path switching valve is fully closed, the refrigerator compartment damper is opened, and the freezer compartment damper is closed, so that the compressor is stopped after the operation of recovering the accumulated refrigerant in the evaporator and the dew-proof pipe. At the same time, by opening the flow path switching valve to the bypass path side, the recovered high-pressure refrigerant is supplied to the evaporator, and after a predetermined time, the defrost heater provided in the vicinity of the evaporator is energized. is there.

As a result, when the refrigerant in the refrigeration cycle is recovered in the main condenser, the refrigerant can be easily recovered and the recovery time can be shortened while suppressing an excessive decrease in the evaporator temperature, so that the evaporator can be heated. When used, a sufficient amount of refrigerant can be supplied. In addition, the quality of the compressor can be improved in order to suppress the decrease in the evaporator temperature. Therefore, the electric power of the defrost heater can be stably reduced, and the energy saving of the refrigerator can be achieved.

The second invention is the first invention, in which the temperature sensor is provided near the outlet of the evaporator, and the flow path switching valve is fully closed while the evaporator fan and the compressor provided in the vicinity of the evaporator are being operated. the refrigerating chamber to open the damper to close the freezer compartment damper, the refrigerant when the temperature of the temperature sensor in the evaporator and a refrigerant recovery operation for recovering the residence refrigerant of the anti-condensation in the pipe reaches a predetermined temperature while This is to end the collection operation.

As a result, when the refrigerant in the refrigeration cycle is recovered to the main condenser, the temperature of the evaporator starts to rise from the inlet side of the evaporator, and the outlet side of the evaporator rises with a delay, but near the outlet of the evaporator. By detecting the temperature, the refrigerant can be reliably recovered. Therefore, by stably securing the refrigerant for heating, the amount of electric power of the defrost heater can be stably reduced, and the energy saving of the refrigerator can be achieved.

In the third invention, in the second invention , the refrigerant recovery operation is terminated when the temperature of the temperature sensor rises from the lowest point to a predetermined value.

As a result, the refrigerant in the refrigeration cycle can be reliably recovered in the main condenser, and the refrigerant recovery time can be optimized. Therefore, since the time required for the defrosting operation is shortened, the time required for defrosting, that is, the non-cooling time for not cooling the inside of the refrigerator is shortened, energy saving of the refrigerator is achieved, and the temperature rise inside the refrigerator is suppressed, resulting in deterioration of food quality. Can be suppressed. In addition, the time required for defrosting is shortened and the temperature inside the refrigerator is less likely to rise, which means that the cooling time after defrosting can also be shortened. Energy saving can be achieved.

In the fourth aspect of the invention, in any one of the first to third inventions, the evaporator is provided with an inlet-side connection portion of a bypass path, and the outlet of the bypass path is connected to the inlet-side connection portion of the evaporator. It is a thing.

In the refrigeration cycle of the refrigerator, the throttle outlet, that is, the evaporator inlet, is provided with a sensor that detects the temperature because the temperature does not easily rise during defrosting, and the sensor detects the predetermined temperature to determine the end of defrosting. However, by connecting the outlet of the bypass path to the inlet side of the evaporator, the temperature rise can be detected by using the temperature sensor already arranged, so that there is no need to increase the cost and the cost performance is high. Furthermore, since the high-pressure refrigerant is supplied from the inlet portion where the temperature does not easily rise, the temperature of the evaporator can be raised uniformly without waste when the defrost heater is energized after a predetermined time, so that the energy saving of the refrigerator can be further improved. it can.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the same configurations as those of the conventional example will be designated by the same reference numerals, and detailed description thereof will be omitted. The present invention is not limited to this embodiment.

(Embodiment 1)
FIG. 1 is a vertical sectional view of the refrigerator according to the first embodiment of the present invention, FIG. 2 is a cycle configuration diagram of the refrigerator according to the first embodiment of the present invention, and FIG. 3 is a compressor of the refrigerator according to the first embodiment of the present invention. FIG. 4 is a schematic view of the heat exchange unit of the above, FIG. 4 is a configuration diagram of a refrigerator cooling chamber according to the first embodiment of the present invention, and FIG. 5 is a diagram showing control of the refrigerator during defrosting according to the first embodiment of the present invention. ..

1 to 3, the refrigerator 11 includes a housing 12, a door 13, legs 14 that support the housing 12, a lower machine room 15 provided at the lower part of the housing 12, and an upper portion provided at the upper part of the housing 12. It has a machine room 16, a refrigerating room 17 arranged in the upper part of the housing 12, and a freezing room 18 arranged in the lower part of the housing 12. Further, as parts constituting the refrigerating cycle, a compressor 19 housed in the upper machine room 16, an evaporator 20 housed on the back side of the freezing room 18, and a main condenser 21 housed in the lower machine room 15 are included. Have. Further, it has a partition wall 22 for partitioning the lower machine room 15, a fan 23 attached to the partition wall 22 for air-cooling the main condenser 21, an evaporating dish 24 installed on the leeward side of the partition wall 22, and a bottom plate 25 for the lower machine room 15. There is.

Here, the compressor 19 is a variable speed compressor, and uses six rotation speeds selected from 20 to 80 rps. This is to adjust the refrigerating capacity by switching the rotation speed of the compressor 19 in six stages from low speed to high speed while avoiding resonance of piping and the like. The compressor 19 operates at a low speed at the time of starting, and increases in speed as the operation time for cooling the refrigerating chamber 17 or the freezing chamber 18 becomes longer. This is because the most efficient low speed is mainly used, and a relatively high rotation speed suitable for an increase in the load of the refrigerating chamber 17 or the freezing chamber 18 due to a high outside temperature or opening / closing of a door is used. .. At this time, the rotation speed of the compressor 19 is controlled independently of the cooling operation mode of the refrigerator 11, but the rotation speed at the time of starting the PC cooling mode having a high evaporation temperature and a relatively large refrigerating capacity is higher than that of the FC cooling mode. It may be set low. Further, the refrigerating capacity may be adjusted while decelerating the compressor 19 as the temperature of the refrigerating chamber 17 or the freezing chamber 18 decreases.

Further, it has a plurality of intake ports 26 provided on the bottom plate 25, an exhaust port 27 provided on the back side of the lower machine room 15, and a communication air passage 28 connecting the discharge port 27 of the lower machine room 15 and the upper machine room 16. doing. Here, the lower machine room 15 is divided into two chambers by a partition wall 22, and the main condenser 21 is housed on the leeward side of the fan 23 and the evaporating dish 24 is housed on the leeward side.

Further, as a component constituting the refrigeration cycle, a flow path switching valve 40 located on the downstream side of the main condenser 21 and drying the circulating refrigerant, and on the downstream side of the dryer 38 to control the flow of the refrigerant. , A dew-proof pipe 41 that is located on the downstream side of the flow path switching valve 40 and is thermally coupled to the outer surface of the housing 12 around the opening of the freezer chamber 18, and a throttle 42 that connects the dew-proof pipe 41 and the evaporator 20. It has a bypass path 43 that connects the downstream side of the flow path switching valve 40 and the evaporator 20 in parallel with the dew-proof pipe 41, and a heat exchange unit 44 that thermally couples with the compressor 19 in the path of the bypass path 43. ..

Here, the heat exchange unit 44 that heat-bonds to the compressor 19 is installed on the surface of the airtight container 70 that forms the outer shell of the compressor 19, and the heat conductive butyl rubber 71 that heat-bonds the bypass path 43 and the airtight container 70 is hermetically sealed. It is composed of an aluminum foil tape 72 fixed to the container 70. The thermally conductive butyl rubber 71 has a thermal conductivity of 2.1 W / mK, a thickness of 1 mm, and a width of 10 mm, and is installed so as to sandwich a bypass path 43 that substantially goes around the center of the upper and lower sides of the closed container 70. As a result, a sufficient amount of heat exchange between the bypass path 43 and the closed container 70 can be secured, and the high-pressure refrigerant passing through the inside of the bypass path 43 is heated by the heat exchange unit 44 to be in a substantially gaseous state. it can. The same effect can be expected by thermally coupling the bypass path 43 and the closed container 70 with a metal having high thermal conductivity such as solder or brazing material instead of the heat conductive butyl rubber 71, but the closed container 70 And rust prevention treatment of the thermal coupling part is required. When the thermally conductive butyl rubber 71 is used, there is an advantage that the closed container 70 can be used after being coated with rust preventive coating, and an effect of suppressing the vibration of the compressor 19 from being transmitted to the bypass path 43 can be expected. Further, the closed container 70 has a mass ratio of about 40% of that of the compressor 19, and it is estimated that the compressor 19 holds about 40% of the waste heat that stores sensible heat, and the refrigerant inside the compressor 19 Since it is thermally coupled to the waste heat stored in the mechanical parts inside the compressor 19 via (not shown) or refrigerating machine oil (not shown), the heat exchange portion 44 should be formed on the surface of the closed container 70. For example, the waste heat stored in the sensible heat of the compressor 19 can be effectively used.

In the present embodiment, the heat exchange portion that thermally couples with the compressor 19 is performed on the outer shell of the compressor 19, but it may be thermally coupled to the inside of the compressor 19. The compressor 19 is a closed container 70 that forms an outer shell, a piston 91 that is installed inside the closed container 70 and forms a compression mechanism, a cylinder 92 and a shaft 93, and a motor unit 94 that drives the compression mechanism via the shaft 93. It consists of a refrigerating machine oil 95 used for lubricating a compression mechanism. Here, in order to exchange heat inside the compressor 19, a part of the bypass path 43 penetrates the closed container 70 and is installed in the refrigerating machine oil 95 staying in the lower part of the closed container 70 to be installed with the compressor 19. A heat exchange unit 96 that heat-bonds is formed. As a result, the amount of heat exchange between the bypass path 43 and the closed container 70 can be sufficiently secured, and the high-pressure refrigerant passing through the inside of the bypass path 43 is heated by the heat exchange unit 96 to be in a substantially gaseous state. it can. Further, since the heat exchange coupling between the bypass path 43 and the closed container 70 is realized without impairing the heat dissipation from the surface of the closed container 70, the heat radiation of the compressor 19 is impaired during the normal cooling operation and the temperature rises, so that the compressor It does not cause a decrease in efficiency of 19.

As a result, it is possible to secure a sufficient amount of heat exchange between the bypass path 43 and the closed container 70 without impairing heat dissipation from the surface of the closed container 70, and further to save energy in the refrigerator.

In the present embodiment, the bypass path 43 uses a copper tube having an outer diameter of φ2 mm and an inner diameter of φ1 mm, which is smaller than the dimensions of the main condenser 21 and the upstream pipe of φ4 mm. As a result, in the heat exchange section 44 that thermally couples with the compressor 19 in the path of the bypass path 43, the pressure is slightly lowered from the main condenser 21, and the heat exchange section 44 facilitates heat exchange. The inner diameter of the bypass path 43 is preferably φ0.5 to φ3 in consideration of workability. In the present embodiment, the efficiency of heat exchange is improved by the diameter of the bypass path 43, but a throttle adjusting mechanism such as an expansion valve is provided between the heat exchange unit 44 that thermally couples with the compressor 19 and the main condenser 21. However, the same effect can be obtained.

Further, the flow path switching valve 40 can control the opening and closing of the flow of the refrigerant independently of the dew-proof pipe 41 and the bypass path 43. Normally, the flow path switching valve 40 opens the flow path from the main condenser 21 to the dew-proof pipe 41 and keeps the flow path from the main condenser 21 to the bypass path 43 closed. The flow path is opened and closed only during frost.

As the air passage configuration in the present embodiment, there is a cooling chamber 73 on the back surface of the freezing chamber 18, an evaporator 20 is arranged in the cooling chamber 73, and an evaporator cover having an evaporator fan 30 (shown in the figure). It is covered. The cold air generated by the evaporator 20 is blown to the refrigerating chamber 17 and the freezing chamber 18 by the evaporator fan 30 near the evaporator.

The cold air blown through the evaporator cover circulates and cools the inside of the freezing chamber 18, and the cold air returns to the cooling chamber 73 from the freezing chamber cold air return port (not shown) provided under the evaporator cover. .. During this time, a freezing chamber damper 31 that blocks the flow of cold air in the freezing chamber is provided. Further, an FCC temperature sensor 34 for detecting the temperature of the freezing chamber 18 is arranged in the freezing chamber 18.

On the other hand, the cold air blown toward the refrigerating chamber 17 is the target internal temperature by the refrigerating chamber damper 32 that shuts off the cold air supplied to the refrigerating chamber 17 and the PCC temperature sensor 35 that detects the temperature of the refrigerating chamber 17. It is controlled while opening and closing the damper so that it becomes equivalent to. After passing through the refrigerating chamber damper 32, the cold air is blown to the refrigerating chamber 17 through the duct 33 that supplies the cold air to the refrigerating chamber 17, cools and circulates in the refrigerating chamber, and then passes through the side surface of the evaporator 20. It returns to the cooling chamber 73 through the return duct 102. The duct 33 is formed along the wall surface where the refrigerating chamber 17 and the upper machine room 16 are adjacent to each other, and a part of the cold air passing through the duct 33 is discharged from the vicinity of the center of the refrigerating room. After passing through the adjacent wall surface while cooling, it is discharged from the upper part of the refrigerating room 17.

Next, the configuration around the evaporator in this embodiment will be described.

A cooling chamber 73 is provided on the back surface of the refrigerator main body 11, and a fin-and-tube type evaporator 20 for generating cold air is typically arranged on the back surface of the freezing chamber 18 in the cooling chamber 73. .. Inside the front chamber of the cooling chamber 73, an evaporator cover is arranged to cover the evaporator 20 provided with a freezing chamber cold air return port for the cold air cooling the freezing chamber 18 to return to the evaporator 20. Further, aluminum or copper is used as the material of the evaporator 20.

The evaporator cover is composed of an evaporator front side cover inside the refrigerator and an evaporator rear side cover on the evaporator side, and a metal heat transfer promoting member (shown) is on the evaporator side of the evaporator rear side cover. ) Is placed. In the present embodiment, in consideration of cost, an aluminum foil having t = 8 μm is used for promoting heat transfer during defrosting, the vertical dimension is from the lower end to the upper end of the evaporator 20, and the left and right dimensions are between the fins of the evaporator 20. By pasting with a large size from to +15 mm, heat transfer during defrosting is promoted and the defrosting time shortening effect is obtained by improving defrosting efficiency. In addition, in order to obtain a further effect, an aluminum foil may be arranged in the inner box on the back side of the evaporator 20. Further, if it is made of an aluminum plate plate having a thickness larger than that of aluminum foil or a material having a higher thermal conductivity than aluminum (for example, copper), the effect of promoting heat transfer is further exhibited.

An evaporator fan 30 for blowing cold air generated by the evaporator 20 is arranged in the refrigerating chamber 17 and the freezing chamber 18 by a forced convection method in the vicinity of the evaporator 20 (for example, the upper space), and cooling is performed below the evaporator 20. A glass tube heater made of a glass tube is provided as a defrost heater 37 for defrosting the frost that sometimes adheres to the evaporator 20 and the evaporator fan 30. A cover (not shown) that covers the glass tube heater 37 is arranged above the glass tube heater 37, and water droplets dropped from the evaporator 20 during defrosting fall directly onto the surface of the glass tube that has become hot due to defrosting. The dimensions are equal to or larger than the diameter and width of the glass tube so that no sizzling noise is generated.

Below the glass tube heater 37, an evaporating dish 24 that receives the defrosted water from which the frost adhering to the evaporator 20 is thawed and falls is arranged.

On the right side of the evaporator 20, there is a refrigerating chamber return duct 102 in which the cold air that has cooled the refrigerating chamber 17 returns to the evaporator 20, and the cold air guided by the refrigerating chamber returning duct 102 returns to the freezer chamber at the lower part of the evaporator 20. It merges with the freezer cool air from the mouth and flows to the evaporator 20 for heat exchange again.

Here, as a refrigerant for a refrigeration cycle in recent years, isobutane, which is a flammable refrigerant having a small global warming potential, is used from the viewpoint of global environmental protection. This hydrocarbon, isobutane, has a specific density about twice that of air at room temperature and atmospheric pressure (at 2.04 and 300K). As a result, the amount of refrigerant charged can be reduced as compared with the conventional case, the cost is low, and the amount of leakage in the unlikely event that the flammable refrigerant leaks is reduced, so that safety can be further improved.

In the present embodiment, isobutane is used as the refrigerant, and the maximum temperature of the glass tube surface which is the outer shell of the glass tube heater 37 at the time of defrosting is regulated as an explosion-proof measure. Therefore, in order to reduce the temperature of the surface of the glass tube, a double glass tube heater in which the glass tube is doubly formed is adopted. In addition, as a means for reducing the temperature of the surface of the glass tube, a member having high heat dissipation (for example, aluminum fin) can be wound around the surface of the glass tube. At this time, the external dimensions of the glass tube heater 37 can be reduced by making the glass tube single.

As a means for improving the efficiency at the time of defrosting, a pipe heater in close contact with the evaporator 20 may be used in combination with the glass tube heater 37. In this case, the evaporator 20 is efficiently defrosted by direct heat transfer from the pipe heater, and the frost adhering to the evaporating dish 24 and the evaporator fan 30 around the evaporator 20 is removed by the glass tube heater 37. Since it can be melted, the defrosting time can be shortened, energy saving and an increase in the temperature inside the refrigerator during the defrosting time can be suppressed.

Among them, the evaporator 20 in the present embodiment is a typical fin-and-tube type evaporator 20 like the generally used evaporator 20, and the refrigerant pipe having fins is vertically oriented. It is an evaporator 20 laminated in the above. The evaporator 20 has a configuration in which 10 stages of refrigerant pipes in the vertical direction and 30 refrigerant pipes from 3 rows of refrigerant pipes in the front-rear direction are arranged in the evaporator 20. The refrigerant pipe at No. 20 has a configuration in which the width dimension of the lower part is shorter than that of the upper part.

Here, as a configuration around the evaporator of the refrigeration cycle in the present embodiment, the inlet portion of the evaporator 20 is connected by merging and connecting the throttle 42 and the outlet portion of the bypass path 43 with a Y-shaped joint pipe. The evaporator outlet is connected to a pipe leading to the compressor 19. The evaporator 20 has a DEF temperature sensor 36 that detects the temperature of the evaporator 20 and is arranged at an inlet pipe portion.

In the cooling stop state (hereinafter, this operation is referred to as "OFF mode") in which the air cooling fan 23, the compressor 19, and the evaporator fan 30 are all stopped, the temperature detected by the FCC temperature sensor 34 reaches the predetermined FCC_ON temperature. When the temperature rises or the temperature detected by the PCC temperature sensor 35 rises to the predetermined PCC_ON temperature, the freezer compartment damper 31 is closed, the refrigerating chamber damper 32 is opened, and the compressor 19, fan 23, and evaporator fan are closed. 30 is driven (hereinafter, this operation is referred to as "PC cooling mode").

In the PC cooling mode, by driving the air cooling fan 23, the main condenser 21 side of the lower machine room 15 partitioned by the partition wall 22 becomes a negative pressure, external air is sucked from a plurality of intake ports 26, and the evaporating dish 24 side is positive. It becomes pressure and the air in the lower machine room 15 is discharged to the outside from the plurality of discharge ports 27.

On the other hand, the refrigerant discharged from the compressor 19 is condensed by leaving a part of the gas while exchanging heat with the outside air in the main condenser 21, and then the moisture is removed by the dryer 38 and prevented via the flow path switching valve 40. It is supplied to the dew pipe 41. The refrigerant that has passed through the dew-proof pipe 41 dissipates heat through the housing 12 while warming the opening of the freezer chamber 18, condenses it, and then decompresses it with the throttle 42 and evaporates it with the evaporator 20 while storing the refrigerator chamber 17. While exchanging heat with the internal air to cool the refrigerating chamber 17, it returns to the compressor 19 as a gaseous refrigerant.

During the PC cooling mode, when the temperature detected by the FCC temperature sensor 34 drops and rises to the predetermined value of FCC_OFF temperature and the temperature detected by the PCC temperature sensor 35 drops to the predetermined value of PCC_OFF temperature, the mode shifts to the OFF mode.

Further, during the PC cooling mode, when the temperature detected by the FCC temperature sensor 34 indicates a temperature higher than the predetermined value of the FCC_OFF temperature and the temperature detected by the PCC temperature sensor 35 drops to the predetermined value of the PCC_OFF temperature, the freezer compartment damper 31 is opened, the refrigerator damper 32 is closed, and the compressor 19, the air cooling fan 23, and the evaporator fan 30 are driven. Hereinafter, by operating the refrigerating cycle in the same manner as the PC cooling, the refrigerator 20 is cooled by exchanging heat between the air inside the refrigerating chamber 18 and the evaporator 20 (hereinafter, this operation is referred to as “FC cooling mode”). ..

During the FC cooling mode, when the temperature detected by the FCC temperature sensor 34 drops to the predetermined value of FCC_OFF temperature and the temperature detected by the PCC temperature sensor 35 indicates the predetermined value of PCC_ON temperature or higher, the mode shifts to the PC cooling mode. ..

Further, during the FC cooling mode, when the temperature detected by the FCC temperature sensor 34 drops to the FCC_OFF temperature of a predetermined value and the temperature detected by the PCC temperature sensor 35 indicates a temperature lower than the PCC_ON temperature of the predetermined value, the OFF mode is used. Transition to.

Further, when the temperature detected by the FCC temperature sensor 34 indicates a temperature higher than the predetermined FCC_ON temperature by opening / closing the door of the freezing room during the PC cooling mode, or opening / closing the door of the refrigerating room during the FC cooling mode, etc. When the temperature detected by the PCC temperature sensor 35 indicates a temperature higher than the predetermined value of the PCC_ON temperature, the freezer compartment damper 31 may be opened, the refrigerating chamber damper 32 may also be opened, and the refrigerating chamber and the freezing chamber may be cooled. (Hereinafter, this operation is referred to as "PC + FC cooling mode").

Here, the operation operation at the time of defrosting the refrigerator of the present embodiment will be described.

In FIG. 5, the state “opening / closing” of the flow path switching valve 40 is to open the flow path from the main condenser 21 to the dew-proof pipe 41 and block the flow path from the main condenser 21 to the bypass path 43. Means. Further, the state "closed / opened" of the flow path switching valve 40 blocks the flow path from the main condenser 21 to the dew-proof pipe 41 and opens the flow path from the main condenser 21 to the bypass path 43. means. The state "closed" of the flow path switching valve 40 means that the flow path from the main condenser 21 to the dew-proof pipe 41 is closed and the flow path from the main condenser 21 to the bypass path 43 is closed. ..

The time chart of FIG. 5 shows the control at the time of defrosting of the present embodiment.

When the integrated operation time of the compressor 19 or the time elapsed since the previous defrosting operation reaches a predetermined time, the mode shifts to the defrosting mode in which the frost formation of the evaporator 20 is heated and melted.

In the defrosting mode section a, first, in order to suppress the temperature rise of the refrigerating chamber 17, the refrigerating chamber 17 and the freezing chamber 18 are cooled for a predetermined time in the same manner as in the PC + FC cooling mode, and then the temperature at the time of defrosting. In order to suppress the temperature rise of the freezing chamber 18 which is easily affected by the rise, the freezing chamber 18 is cooled for a predetermined time in the same manner as in the FC cooling mode. If the temperature inside the refrigerator compartment 17 becomes 0 ° C. or lower, the stored food may freeze. Therefore, in some cases, the PC + FC cooling mode may be omitted and only the FC cooling mode may be used. Next, in the section b, the flow path from the main condenser 21 to the dew-proof pipe 41 and the bypass path 43 is opened by setting the flow path switching valve 40 to a fully closed state while operating the compressor 19. The refrigerant that is blocked together and stays in the dew-proof pipe 41, the evaporator 20, and the bypass path 43 is collected in the main condenser 21. Then, in the section c, the compressor 19 is stopped and the flow path switching valve 40 is switched to open the flow path from the main condenser 21 to the bypass path 43, so that the main condenser 21 is passed through the bypass path 43. The high-pressure refrigerant recovered in the above is supplied to the evaporator 20. At this time, the high-pressure refrigerant is heated by the waste heat of the compressor 19 which is stopped in the heat exchange unit 44 provided in the bypass path 43, and the dryness is increased. This is because when the high-pressure refrigerant is recovered in the main condenser 21 in the section b, it dissipates heat to the outside air and most of it condenses. Therefore, as compared with the case where the high-pressure refrigerant is supplied to the evaporator 20 without being heated by the heat exchange unit 44 in the section c, the amount of heat due to the latent heat of condensation is evaporated in addition to the sensible heat of the high-pressure refrigerant maintained at the outside air temperature. It can be added to the vessel 20. Next, in section d, the defrost heater 37 attached to the evaporator 20 is energized to complete defrosting. The completion of defrosting is determined when the DEF temperature sensor 36 reaches a predetermined temperature. Then, in the section e, the flow path switching valve 40 is switched to block the flow path from the main condenser 21 to the bypass path 43, and the flow path from the main condenser 21 to the dew-proof pipe 41 is opened to perform the refrigeration cycle. The pressure inside is equalized, and normal operation is restarted from the section f.

In this series of operations, the evaporator fan 30 is also operated during the operation of the compressor 19 in the section b. As a result, the quality of the compressor is improved by suppressing an excessive temperature drop of the evaporator 20, and the recovery time of the refrigerant is shortened, so that the time can be shortened. Further, in the later section c, a sufficient amount of refrigerant can be supplied when the refrigerant is supplied from the main condenser 21 to the evaporator 20, so that the temperature raising effect in the evaporator 20 is enhanced, and the defrost heater 37 in the section c removes the refrigerant. Savings can be achieved by shortening the frost time. If the defrosting time is shortened, the non-cooling time during which the compressor 19 is stopped is also shortened, so that the temperature rise of the food itself can be suppressed. This is also a favorable condition for food preservation that deteriorates due to temperature fluctuations.

By operating the evaporator fan 30 in the section b, it is possible to utilize the heat of the sensible heat change and the latent heat change in which the refrigerant changes phase in the evaporator 20, and the refrigerating chamber damper 32 is opened to open the freezing chamber damper 31. By closing the refrigerator, the temperature of the cold air blown to each chamber rises due to the effect of the temperature rise of the evaporator 20 due to the operation of the evaporator fan 30, but the freezer chamber 18 is closed because the freezer damper 31 is closed. Since only the refrigerating chamber 17 can be cooled because the air is not blown to the refrigerator and only the refrigerating chamber 17 can be blown, the temperature rise in the refrigerating chamber 17 due to the shutdown of the compressor during defrosting can be suppressed. Deterioration of stored food can be suppressed. Further, when the evaporator fan 30 is operated, the temperature of the evaporator itself is raised by the return air that has passed from the refrigerating chamber 17 to the refrigerating chamber return duct 102, so that the starting temperature at the time of defrosting the heater in the section c is also raised and the heater is energized. Time can be shortened and energy can be saved.

Further, a second DFC temperature sensor 110 is provided in the vicinity of the evaporator outlet of the evaporator 20, and the temperature of the second DFC temperature sensor 110 is set to a predetermined temperature during the refrigerant recovery operation to the main condenser 21 in the section b. The refrigerant recovery operation may be terminated at that time. In this case, when the refrigerant in the refrigeration cycle is recovered in the main condenser 21, the temperature of the evaporator 20 starts to rise from the inlet side of the evaporator, and the outlet side of the evaporator 20 rises with a delay, but the evaporator 20 By detecting the temperature in the vicinity of the outlet of the above, the refrigerant remaining in the evaporator 20 can be reliably recovered. Therefore, by stably securing the supplied refrigerant for heating in the section c, the electric power amount of the defrost heater 37 in the section d can be stably reduced, and the energy saving of the refrigerator can be achieved. it can.

Further, by ending the refrigerant recovery operation in the section b when the DFC temperature sensor 36 or the second DFC temperature sensor 110 rises in a predetermined value temperature from the lowest temperature point, the refrigerating cycle including the evaporator is completed. The refrigerant can be reliably recovered in the main condenser 21. Further, by using the second DFC temperature sensor 110 arranged at the outlet of the evaporator, it is more preferable because the temperature on the outlet side where the temperature rise is slow due to the accumulator at the time of recovering the refrigerant can be detected. Further, it can be completed in the optimum refrigerant recovery time. Therefore, since the time for the defrosting operation is shortened, the time required for defrosting, that is, the non-cooling time for not cooling the inside of the refrigerator is shortened, the energy of the refrigerator is saved, the temperature inside the refrigerator is suppressed, and the quality of food deteriorates. Can be suppressed. In addition, the time required for defrosting is shortened and the temperature inside the refrigerator is less likely to rise, which means that the cooling time after defrosting can also be shortened. Therefore, considering the heat load on which the defrosting heater 37 is energized, the refrigerator as a whole Energy saving can be achieved.

Further, in the present embodiment, the outlet of the bypass path 43 is connected to the evaporator inlet side. As a result, in the refrigerating cycle of the refrigerator, the outlet portion of the throttle 42, that is, the inlet portion of the evaporator is provided with a DFC temperature sensor 36 that detects the temperature because the temperature does not easily rise during defrosting, and the sensor detects a predetermined temperature. Although the end of defrosting is determined by this, the temperature of the evaporator inlet is raised in advance by connecting the outlet of the bypass path 43 to supply the high-pressure refrigerant from the evaporator inlet side where the temperature does not easily rise. It promotes the temperature rise in the section d.

Since the outlet of the bypass path 43 is connected to the inlet side of the evaporator, the temperature rise can be detected by using the DFC temperature sensor 36 already arranged. As a result, it is possible to provide a refrigerator with high cost performance without the need for cost increase.

The section d may be started before the end of the section c. In this case, the high-pressure refrigerant recovered in the main condenser 21 by stopping the compressor 19 and switching the flow path switching valve 40 to open the flow path from the main condenser 21 to the bypass path 43 in the section c. Is supplied to the evaporator 20, and the refrigerant supplied inside the evaporator 20 condenses, so that the temperature of the evaporator rises due to the heat of condensation. By shifting to d and starting energization of the defrost heater 37, the temperature of the evaporator 20 can be effectively raised without causing a temperature drop loss after the maximum temperature in the section c is exceeded. In the present embodiment, the evaporator temperature in the section c is detected by the DFC temperature sensor 36, but the second DFC temperature sensor 110 may be used, or the time for each section is determined to control the time. Is also good. Further, switching control may be performed by both temperature and time. In this case, even if the amount of frost adhering to the evaporator changes due to, for example, opening and closing the door, heat loss to be supplied at the time of defrosting by section switching does not occur.

Further, in the present embodiment, the refrigerant state in the section c is grasped by detecting the evaporator temperature using the temperature sensor, and then the defrost heater 37 is energized in the section d, but the pressure sensor is used. It may be used to shift to the section d when the high pressure and the low pressure in the evaporator are balanced and balanced.

In the present embodiment, the main condenser 21 is a forced air-cooled type condenser, but a second dew-proof pipe that is thermally coupled to the side surface or the back surface of the housing 12 may be used. Unlike the dew-proof pipe 41 that is thermally coupled to the periphery of the openings of the refrigerating chamber 17 and the freezing chamber 18, the second dew-proof pipe that is thermally coupled to the side surface and the back surface of the housing 12 has the outside air temperature even when the compressor 19 is stopped. Since it is maintained in the vicinity, the same effect can be expected even if it is used as the main condenser 21.

In the present embodiment, the flow path switching valve 40 and the evaporator 20 are connected by a bypass path 43, but the flow velocity of the high-pressure refrigerant supplied to the evaporator 20 at the time of defrosting is too fast to generate a flow noise. In this case, the flow path resistance for adjusting the flow velocity may be connected in series with the bypass path 43.

In the present embodiment, the high-pressure refrigerant is directly supplied to the evaporator 20 without passing through the dew-proof pipe 41 and the throttle 42 during defrosting, so that the main condenser 21 is stopped when the compressor 19 is stopped. Although it was avoided that the temperature of the high-pressure refrigerant was lowered due to the influence of the dew-proof pipe 41 which became lower than the dew-proof pipe 41, when the temperature of the evaporator 20 became higher than that of the dew-proof pipe 41 due to the progress of defrosting, the temperature of the evaporator 20 became higher than that of the dew-proof pipe 41. Since the high-pressure refrigerant may flow back from the evaporator 20 to the dew-proof pipe 41, a check valve or a two-way valve for preventing backflow is provided in the path from the outlet of the dew-proof pipe 41 to the inlet of the evaporator 20. May be good.

In the present embodiment, a glass tube heater is used as the defrost heater 37 at the time of defrosting, but when a pipe heater is combined with the glass tube heater, the glass can be optimized by optimizing each other's heater capacities. It is possible to reduce the capacity of the tube heater. By lowering the heater capacity, the temperature of the outer shell of the glass tube heater during defrosting can also be lowered, so that red heat during defrosting can also be suppressed.

Furthermore, the fact that the input time of the glass tube heater during defrosting can be reduced means that the temperature rise can be suppressed by shortening the non-cooling operation time and the temperature rise due to the heat generated by the glass tube heater itself can be suppressed. It also applies to foods that are used. Frozen foods stored in the refrigerator are frosted due to temperature rise during the non-cooling operation time during defrosting, heat transfer from the temperature of the glass tube heater itself, and inflow of warm air into the refrigerator during defrosting. Although it deteriorates due to the influence of heat fluctuation, in the present embodiment, deterioration of food can be suppressed even when it is stored for a long period of time.

As described above, in the refrigerator according to the present invention, the refrigerant staying in the evaporator and the dew-proof pipe is collected in the main condenser, and the high-pressure refrigerant in the refrigeration cycle flows into the evaporator due to the pressure difference to add the evaporator. Since the output of the electric heater for defrosting can be reduced by using the heating energy, it can be applied to other refrigerating and refrigerating applied products such as commercial refrigerators.

11 Refrigerator 12 Housing 13 Door 14 Leg 15 Lower machine room 16 Upper machine room 17 Refrigerator room 18 Freezer room 19 Compressor 20 Evaporator 21 Main condenser 22 Partition 23 Fan (air cooling fan)
24 Evaporating dish 25 Bottom plate 26 Intake port 27 Outlet port 28 Communication air passage 30 Evaporator fan 31 Refrigerator room damper 32 Refrigerator room damper 33 Duct 34 FCC temperature sensor 35 PCC temperature sensor 36 DEF temperature sensor 37 Defrost heater (glass tube heater)
38 Dryer 40 Flow path switching valve 41 Dew-proof pipe 42 Squeezing 43 Bypass path 44 Heat exchange part 70 Sealed container 71 Thermally conductive butyl rubber 72 Aluminum foil tape 73 Cooling chamber 102 Refrigerating chamber return duct 110 Temperature sensor (second DFC temperature sensor) )

Claims (4)

A refrigerating cycle having at least a compressor, an evaporator, a main condenser, and a dew-proof pipe is provided, and a flow path switching valve connected to the downstream side of the main condenser and dew-proof connected to the downstream side of the flow path switching valve. It has a pipe and a bypass path having a heat exchange portion that is connected in parallel with the dew-proof pipe and partially heat-bonds to a compressor, and supplies cold air to a freezer compartment and a refrigerator compartment formed by a heat insulating wall. In a refrigerator equipped with a freezer compartment damper and a refrigerating chamber damper, respectively, when defrosting the evaporator, the flow path of the evaporator fan and the compressor provided in the vicinity of the evaporator are being operated. By fully closing the switching valve, opening the refrigerating chamber damper, and closing the refrigerating chamber damper, after the recovery operation of the accumulated refrigerant in the evaporator and the dew-proof pipe, the compressor is stopped and the flow path is switched. A refrigerator characterized in that the recovered high-pressure refrigerant is supplied to the evaporator by opening the valve to the bypass path side, and after a predetermined time, a defrost heater provided in the vicinity of the compressor is energized. A temperature sensor is provided in the vicinity of the outlet of the evaporator, and the flow path switching valve is fully closed and the refrigerating chamber damper is opened while the evaporator fan and the compressor provided in the vicinity of the evaporator are being operated. The claim is characterized in that the refrigerant recovery operation is terminated when the temperature of the temperature sensor reaches a predetermined temperature during the refrigerant recovery operation of closing the damper and recovering the accumulated refrigerant in the evaporator and the dew-proof pipe. Item 1. The refrigerator according to item 1. The refrigerator according to claim 2 , wherein the refrigerant recovery operation is terminated when the temperature of the temperature sensor rises from the lowest point to a predetermined temperature. The invention according to any one of claims 1 to 3, wherein the evaporator is provided with an inlet-side connection portion of the bypass path, and the outlet of the bypass path is connected to the inlet-side connection portion of the evaporator. Refrigerator.

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