JP7442045B2 - refrigerator - Google Patents

Description

The present disclosure relates to refrigerators.

Patent Document 1 discloses a refrigerator that performs defrosting. This refrigerator has a path connecting the outlet of the compressor and a defrosting pipe disposed in the evaporator, and performs defrosting by supplying high-temperature refrigerant discharged from the compressor to the defrosting pipe.

Patent Document 2 discloses a refrigerator that also performs defrosting. This refrigerator uses a four-way valve to switch the paths between the evaporator and external condenser, supplying high-temperature refrigerant discharged from the compressor to the evaporator for defrosting, and evaporating it in the external condenser. After that, it is refluxed to the compressor.

Japanese Unexamined Patent Publication No. 58-024774 Japanese Patent Application Publication No. 2018-004170

The present disclosure provides a refrigerator that can suppress the generation of sounds that are unpleasant to the user and can reduce the amount of recooling after defrosting by suppressing the temperature rise inside the refrigerator during defrosting.

The refrigerator according to the present disclosure includes a refrigeration cycle including at least a compressor, a first condenser, a second condenser, and an evaporator, and the refrigeration cycle is located downstream of the first condenser. The cooling path is divided into a cooling path that supplies refrigerant to the evaporator to generate cold air, and a defrosting path that heats the refrigerant and supplies the heated refrigerant to the evaporator for defrosting. The refrigerant is supplied to the evaporator after passing through the second condenser, and the refrigerant flowing through the defrosting route is heated by exchanging heat with the route through which refrigerant is supplied from the compressor to the first condenser. The refrigerant heats the evaporator that is thermally connected to the defrosting path, and the refrigerant that radiates heat in the defrosting path is returned to the compressor after being evaporated in the heating side evaporator installed downstream of the evaporator. .

The refrigerator according to the present disclosure uses the condensation heat of the refrigerant for defrosting, suppresses the generation of noise that makes the user uncomfortable, and reduces the amount of recooling after defrosting by suppressing the temperature rise inside the refrigerator during defrosting. can.

Furthermore, since low-temperature air is not discharged from the mechanical parts of the refrigerator, there is no fear of condensation forming around the refrigerator. In addition, since the refrigerator compartment can be cooled without stopping the compressor even during defrosting, it is possible to suppress internal temperature fluctuations and suppress quality deterioration of fresh foods and the like.

Vertical cross-sectional view of the refrigerator in Embodiment 1 Configuration diagram of first and second machine rooms of the refrigerator in Embodiment 1 Refrigeration cycle configuration diagram of refrigerator in Embodiment 1 Mollier diagram during cooling operation of the refrigerator in Embodiment 1 Mollier diagram during defrosting operation of the refrigerator in Embodiment 1 Configuration diagram of cooling chamber of refrigerator in Embodiment 1 A perspective view of the evaporator of the refrigerator in Embodiment 1 A diagram showing control during defrosting of the refrigerator in Embodiment 1 Flowchart when defrosting the refrigerator in Embodiment 1 Refrigeration cycle configuration diagram of a refrigerator in Embodiment 2 A diagram showing control during defrosting of a refrigerator in Embodiment 2

(Findings, etc. that formed the basis of this disclosure)
Refrigerators are known that have a defrosting function that melts frost that has adhered to an evaporator. The defrosting function is generally performed by providing a defrosting heater below the evaporator and melting the frost by energizing the defrosting heater. On the other hand, Patent Document 1 provides a path that connects the outlet of the compressor and a defrosting pipe installed in the evaporator, and supplies high-temperature refrigerant discharged from the compressor to the defrosting pipe to defrost it. A refrigerator that performs frosting is disclosed. The refrigerator of Patent Document 1 can use the heat of the compressor for defrosting.

In addition, Patent Document 2 discloses that a four-way valve is used to switch the paths between the evaporator and the external condenser, supply high-temperature refrigerant discharged from the compressor to the evaporator for defrosting, and A refrigerator is disclosed that evaporates in a condenser and then returns to a compressor. Similar to the refrigerator of Patent Document 1, the refrigerator of Patent Document 2 can use the heat of the compressor for defrosting.

However, in the configuration of the conventional refrigerator disclosed in Patent Document 1, a three-way valve is used to switch the refrigerant flow path to the defrost pipe during defrosting, but since the flow rate of the refrigerant flowing through the three-way valve is fast, the three-way valve There was a problem in that the noise generated in the refrigerator and the evaporator was unpleasant for users who lived near the refrigerator.

In addition, in the conventional refrigerator configuration disclosed in Patent Document 2, there is a concern that condensation may occur around the refrigerator due to cold air generated in the external condenser during defrosting, and condensation heat recovered by the refrigerant inside the refrigerator The refrigerator is not functioning as a refrigerator during defrosting because it is released externally as heat of evaporation.

Furthermore, in low outside air temperatures such as 16 degrees Celsius or lower, the fan in the machine room is usually not operated. This is to suppress a decrease in cooling system efficiency due to overcondensation of the refrigerant or an increase in compressor oil viscosity.In the refrigerator configuration disclosed in Patent Document 2, the cold air generated in the external condenser during defrosting causes the inside of the machine to cool. There was a problem in that the temperature of the system decreased and the cooling efficiency decreased, resulting in an increase in power consumption.

Generally, during defrosting, the compressor operation is stopped and defrosting is performed by energizing the defrosting heater installed below the evaporator, but since cooling operation is stopped during defrosting, the The temperature inside the refrigerator increases with the outside temperature, and the temperature of the food stored inside the refrigerator also increases. Furthermore, there is a problem in that after defrosting is completed, it is necessary to carry out a cooling operation that takes into account the temperature increase that occurred during defrosting.

The inventors discovered that there were the above problems, and in order to solve the problems, they came up with the subject matter of the present disclosure.

Accordingly, the present disclosure provides a refrigerator that suppresses the generation of sounds that make users uncomfortable, suppresses the rise in internal temperature of the refrigerator during defrosting, and reduces the amount of recooling after defrosting.

Hereinafter, embodiments will be described in detail with reference to the drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanations of well-known matters or redundant explanations of substantially the same configurations may be omitted.

The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

(Embodiment 1)
Embodiment 1 will be described below using FIGS. 1 to 8.

[1-1. composition]
In FIGS. 1 and 2, the refrigerator 100 according to the present embodiment includes a refrigerator compartment 101, a freezer compartment 102 that is partitioned from the refrigerator compartment 101 by a partition 100a and is provided in the lower part of the refrigerator compartment 101, and a The refrigerator 100 has a machine room 103 and a second machine room 104 provided at the bottom of the back of the refrigerator 100.

The first machine room 103 includes a compressor 105, a capacity adjustment condenser 133, a first machine room fan 116, and a suction pipe 126 as components of the refrigeration cycle 150.

The second machine room 104 is divided into two compartments by a partition wall 108. A second machine room fan 109 that air-cools the first condenser 107 is provided in the partition wall 108 . A first condenser 107 is housed on the windward side of the second machine room fan 109, and an evaporation plate 110 is housed on the leeward side of the second machine room fan 109. Further, a flow path switching valve 122 is provided in the second machine room 104.

A cooling chamber 117 is arranged on the back side of the freezing chamber 102, and inside the cooling chamber 117 there is an evaporator 106 that generates cold air, and an evaporator 106 located above the evaporator 106 that generates the cold air generated by the evaporator 106. A cooling fan 111 supplies the refrigerator compartment 101 and the freezing compartment 102, and a defrosting heater 120 is provided below the evaporator 106 as a defrosting means for melting and defrosting the frost attached to the evaporator 106. .

In this embodiment, the defrosting heater 120 is a glass tube heater (not shown). There are various types of defrosting means, and for example, pipe heaters and surface heaters are commonly used. Furthermore, the cooling chamber 117 accommodates a freezing chamber damper 112 for blocking cold air supplied to the freezing chamber 102 and adjusting the air volume.

The evaporator 106 uses a fin-and-tube type, and a temperature sensor 115 for detecting the temperature of the evaporator 106 is installed at an inlet pipe portion (not shown) of the evaporator 106. In this embodiment, the temperature sensor 115 is installed at the inlet pipe portion, but it is preferable to install it at a portion where the temperature rise during defrosting is slowest so as to prevent frost from remaining during defrosting.

Furthermore, the refrigerator compartment 101 accommodates a refrigerator compartment duct 113 that supplies cold air to the refrigerator compartment 101, and a refrigerator compartment damper 114 that adjusts the amount of cold air supplied to the refrigerator compartment 101 by adjusting the angle, shutting off, etc. There is. The opening/closing operation of the refrigerator compartment damper 114 is controlled by the temperature detected by a refrigerator compartment temperature sensor (not shown). A heating side evaporator 131 and a heating side evaporator fan 134 are disposed in the refrigerator compartment duct 113 and above the heating side evaporator 131.

Next, the refrigeration cycle 150 of the refrigerator 100 will be explained using FIGS. 3, 4A, and 4B. Both FIGS. 4A and 4B are Mollier diagrams in which the vertical axis is absolute pressure (kPa) and the horizontal axis is specific enthalpy (kg/kg). Each diagram schematically shows the state at any given moment, and ignores details such as the influence of pressure loss within the piping.

The refrigerant discharged from the compressor 105 exchanges heat with the outside air in the capacity adjustment condenser 133 and the first condenser 107, and is condensed with some gas left behind. The refrigerant that has passed through the first condenser 107 has moisture removed by a dryer 121 and then flows into a flow path switching valve 122 .

The refrigerant flowing into the flow path switching valve 122 is in a two-phase state in which liquid phase refrigerant and gas phase refrigerant coexist. The flow path switching valve 122 branches the refrigerant flow path into a cooling path 151 and a defrosting path 152 . Cooling path 151 is a path that supplies refrigerant to evaporator 106 to generate cold air. On the other hand, the defrosting path 152 is a path that performs defrosting by heating a refrigerant and supplying the heated refrigerant to the evaporator 106.

First, the cooling path 151 will be explained. The cooling path 151 is during the cooling operation and is represented by the Mollier diagram in FIG. 4A. The cooling path 151 is a path through which the refrigerant discharged from the compressor 105 at point a in FIG. 4A flows from the flow path switching valve 122 to the second condenser 123. A door 100 (one or both of the door 101a of the refrigerator compartment 101 and the door 102a of the freezer compartment 102) is placed inside the main body side of the part that contacts the refrigerator main body.

The refrigerant passing through the second condenser 123 heats the doors 101a and 102a of the refrigerator 100 and the partition 100a inside the refrigerator by radiating heat to the outside. (not shown) to prevent condensation from forming.

The refrigerant that has passed through the second condenser 123 at point b and is liquefied is depressurized by the first throttle 124 and evaporated in the evaporator 106 from point c. Thereafter, the refrigerant is evaporated in the evaporator 106 to generate cold air, and this cold air is used to cool the refrigerator compartment 101 and the freezer compartment 102. The refrigerant that has passed through the evaporator 106 returns to the compressor 105 at point d via the suction pipe 126.

Next, the defrosting path 152 will be explained.

The defrosting route 152 is during defrosting operation and is represented by the Mollier diagram in FIG. 4B. The defrosting path 152 is a path through which the refrigerant discharged from the compressor 105 at point e in FIG. 4B flows from the flow path switching valve 122 to the second throttle 127. At point f, the refrigerant is depressurized by the second throttle 127, and at point g, the refrigerant that has passed through the second throttle 127 is transferred from the compressor 105 to the first condenser 107 in the first heat exchange section 128. It is heated and vaporized by exchanging heat with the supply path (point h).

Since the evaporator 106 is heated by the latent heat of condensation generated when the vaporized refrigerant supplied to the evaporator 106 is condensed and liquefied due to a phase change, the evaporator 106 is defrosted from point i to point j. is realized. Thereafter, the refrigerant condensed in the evaporator 106 is evaporated in the heating side evaporator 131 disposed in the refrigerator compartment 101 from point k, and the state of the refrigerant is changed to a gaseous state. is returning to. Since the refrigerant flowing into the compressor 105 is in the gas phase, this prevents the refrigerant from flowing into the compressor 105 in a high-density liquid phase or in a two-phase gas-liquid state, which puts the components inside the compressor 105 at risk of failure. There's no chance of it happening.

Next, the first heat exchange section 128 will be explained.

The first heat exchange section 128 vaporizes the refrigerant condensed in the capacity adjustment condenser 133 and the first condenser 107 from point g to point h in FIG. 4B.

In this embodiment, the first heat exchange unit 128 converts the pipe through which the refrigerant discharged from the second throttle 127 flows into a part of the pipe through which the refrigerant is supplied from the compressor 105 to the first condenser 107. For example, the first heat exchange section 128 is formed by soldering a distance of about 1 m to 2 m.

Furthermore, by forming the first heat exchange section 128 on the outer wall surface 100c of the housing 100b of the refrigerator 100, the sensible heat of the housing 100b made of an iron plate can be used to heat the refrigerant in the defrosting path 152. . In this embodiment, the first heat exchange section 128 is attached to the outer wall surface 100c with aluminum tape (not shown).

Specifically, in the present embodiment, in the first heat exchange section 128, the pipe for supplying the refrigerant from the compressor 105 to the first condenser 107 has a diameter of 3.6 mm, and the refrigerant discharged from the second throttle 127 has a diameter of 3.6 mm. The piping through which the water flows is Φ3.2 mm, and the soldering heat exchange length is 1.2 m.

Here, increasing the diameter of the pipe through which the refrigerant discharged from the second throttle 127 flows will slow down the flow velocity and increase the amount of heat exchange. By making the diameter the same as or smaller than the diameter of the pipe that supplies refrigerant to the first condenser 107, the refrigerant circulation amount can be adjusted in conjunction with the resistance of the second throttle 127, and the The temperature difference between the inlet section 128a and the outlet section 128b of the first heat exchange section 128 is made to be about 7K or more. As a result, at the outlet of the first heat exchange section 128, the refrigerant can cross the saturated vapor line and change its state to the gas phase.

Furthermore, as the refrigerant passes through the capacity adjustment condenser 133 and the first condenser 107, a part of the refrigerant liquefies, the volume of the refrigerant decreases, and the flow rate of the refrigerant flowing through the flow path switching valve 122 becomes slow. Become. In the condensing pipe of the refrigeration cycle 150, the state of the refrigerant near the outlet of the first condenser 107 is close to a liquid phase in a two-phase region.

For example, in the case of condensing pressure: 464 kPa (35 °C) and evaporation pressure: 72 kPa (-20 °C), if the cylinder volume of the compressor 105 is 9.1 cc and the rotation speed is 25 rps, the refrigerant circulation amount is approximately 0.32 g. /s. When this refrigerant passes through a general condenser, the flow velocity is 4.29 m/s on the gas phase side of the two-phase region, while it is 0.10 m/s on the liquid phase side. The higher the flow rate, the louder the sound generated from the flow path switching valve 122 and the evaporator 106, which makes the user feel uncomfortable.

In this embodiment, since the gas phase refrigerant discharged from the compressor 105 and having a high flow rate does not directly flow through the flow path switching valve 122, it is possible to prevent the flow path switching valve 122 from generating sounds that may be unpleasant to the user. It can be suppressed. Further, the vapor phase refrigerant having a high flow rate does not enter the evaporator 106 either. Therefore, it is possible to suppress the generation of a gurgling sound that occurs when refrigerant having a high flow rate enters the evaporator 106 and is rapidly condensed.

Next, the defrosting path 152 will be continuously explained using FIGS. 5 and 6.

FIG. 5 is a configuration diagram of the cooling chamber 117 of the refrigerator 100. FIG. 6 is a diagram of the evaporator 106. The cooling room 117 has a refrigerator room return duct 119 to the right of the evaporator 106 through which cold air that has been cooled and circulated through the refrigerator compartment 101 flows into the evaporator 106 from the lower right side of the evaporator 106 to the lower part of the evaporator 106. The cold air flows in and exchanges heat with the evaporator 106, forming an air path in which the cold air circulates again to the refrigerator compartment 101 and the freezer compartment 102. A cooling fan 111 that blows cold air to the refrigerator compartment 101 and the freezing compartment 102 is arranged above the evaporator 106, and a defrosting heater 120 is arranged below.

The evaporator 106 is a typical fin-and-tube type, and is formed by stacking evaporator cooling pipes 137, which are refrigerant pipes having fins 139, in the vertical direction.

The evaporator 106 has a configuration in which evaporator cooling pipes 137 are arranged in approximately 7 stages in the vertical direction and 3 rows in the front and rear direction. The piping pattern is such that the evaporator cooling inlet 143 and the evaporator cooling outlet 144 are at the same position on the upper right side of the evaporator 106 when viewed from the front.

As a result, the welding position will be closer when attaching the evaporator 106 in the manufacturing process, making the work easier and reducing the number of man-hours, and since there is no lowermost evaporator cooling pipe 137, it can be expected that frost resistance will be improved.

Usually, most of the frost that adheres to the evaporator 106 adheres to the inlet of the return cold air from the inside of the refrigerator that flows into the evaporator 106, and especially to the refrigerating room where it flows from the high-humidity refrigerating room 101 through the refrigerating room return duct 119. Frost tends to adhere to the areas where the cold return air flows in.

In this embodiment, by shortening the evaporator cooling pipe 137 by one stage, it is possible to suppress air path obstruction due to adhesion and growth of frost. Therefore, even under overload conditions due to moisture entering the refrigerator due to the opening and closing of the doors 101a and 102a in hot and humid conditions such as in the summer, the product is less likely to become sluggish due to air path obstruction due to frost growth, and the quality of the product is maintained. It has the effect of improving. Further, in the fins 139, the interval between the fins is larger at the lower part of the evaporator 106, where more moisture flows in, than at the upper part, so that it is difficult for the fins to be blocked by frost or clogging.

Furthermore, the fins 139 of the evaporator 106 in this embodiment are divided into fins 139 for the evaporator cooling pipes 137 stacked in the vertical direction. An evaporator heating pipe 138 is attached between the stacked evaporator cooling pipes 137 and fins 139 so as to cover the outer periphery of the evaporator 106. At this time, evaporator heating pipes 138 are attached to end plates 140 placed at both ends of the evaporator 106. The end plates 140 are usually fixed to both sides of the evaporator 106 with a thickness thicker than the fins 139 so that the pipe of the evaporator 106 has a proper shape.

This time, a recess (not shown) for fixing the evaporator heating pipe 138 is provided between the fins 139 of the end plate 140 as shown in FIG. By fitting, the fins 139 and the evaporator 106 are brought into close contact. Furthermore, by making the end of the fin 139 in contact with the evaporator heating pipe 138 folded back, the evaporator heating pipe 138 and the fin 139 contact with a plane rather than a point or line, improving adhesion and improving heat transfer efficiency. I'm raising it.

The evaporator heating pipe 138 of the refrigerator 100 in this embodiment has a shape that is attached from the top to the bottom of the evaporator 106, centering on the top where the heat of the defrosting heater 120 is difficult to reach, and is a Φ6.35 mm pipe. was used. A total of 12 evaporator heating pipes 138 were installed before and after the evaporator 106, and the evaporator heating pipes 138 were sandwiched from the front and back of the evaporator 106 in close contact with each other like a pipe heater. 137 may be used. In that case, by passing the evaporator heating pipe 138 between the evaporator cooling pipes 137, it is possible to heat the evaporator from the vicinity of the evaporator cooling pipe 137, where the temperature is lowest, so that an improvement in the defrosting effect can be expected.

This time, by heating the evaporator 106 from the outer periphery to the inside, the temperature of the evaporator 106 as a whole can be increased while the temperature is equalized. Further, since the evaporator heating inlet 145 of the evaporator heating pipe 138 is located at the upper part of the evaporator 106 and the refrigerant is heated from a place close to the evaporator accumulator 141 where the temperature rises slowly, the temperature rise is accelerated.

Here, in recent years, isobutane, which is a flammable refrigerant with a low global warming potential, has been used as a refrigerant in the refrigeration cycle 150 from the viewpoint of global environmental conservation. This hydrocarbon, isobutane, has a specific gravity approximately twice that of air at room temperature and atmospheric pressure (2.04, at 300K). As a result, the amount of refrigerant charged can be reduced compared to the conventional method, resulting in low cost, and in the event that flammable refrigerant leaks, the amount of leakage will be reduced, making it possible to further improve safety.

In this embodiment, isobutane is used as the refrigerant, and the maximum temperature of the surface of the glass tube, which is the outer shell of the defrosting heater 120 made of a glass tube heater during defrosting, is regulated for explosion protection. Therefore, in order to reduce the temperature on the surface of the glass tube, a double glass tube heater in which the glass tube is doubled is used. In addition, as a means for reducing the temperature on the surface of the glass tube, it is also possible to wrap a member with high heat dissipation properties (for example, an aluminum fin) around the surface of the glass tube. At this time, by using a single glass tube, the external dimensions of the defrosting heater 120 can be reduced.

The refrigerant that passes through the first heat exchange section 128 and is vaporized beyond the saturated vapor line flows into the evaporator heating inlet 145 and passes to the evaporator heating outlet 146. This part is from point i to point j in FIG. 4B, and by condensing the refrigerant vaporized at point h again, the evaporator heating pipe 138 is heated by the latent heat of condensation of the refrigerant, so the temperature of the evaporator 106 is increased. The temperature rises and the frost that adheres to it melts.

After the refrigerant is vaporized from a two-phase region close to the liquid phase, such as point g, the evaporator 106 is heated by using the latent heat of condensation. This is because a large amount of heat can be obtained compared to the sensible heat of the refrigerant that is used when heating the refrigerant.

For example, a case where the refrigerant temperature is 32° C. will be described as an example. On the left side of the saturated liquid line in FIG. 4A, it is a liquid refrigerant and changes in sensible heat. The amount of sensible heat in that case is 2.48 kJ/kg. Even if the refrigerant temperature is the same at 32° C., the latent heat changes in the two-phase region between the saturated liquid line and the saturated vapor line, and the amount of heat is 321 kJ/kg, so the difference is about 130 times, which is very large.

The value obtained by multiplying this difference by the amount of refrigerant circulation becomes the amount of heat heated in the evaporator 106, but when the latter half of the condensation process near the liquid phase or the amount of sensible heat after condensation is used for defrosting the evaporator. On the other hand, as in the present embodiment, a much larger amount of heat can be obtained by using the amount of heat caused by the change in latent heat after vaporization.

As a result, depending on conditions such as when there is little frost, the temperature of the evaporator 106 is increased during defrosting by heating only using latent heat of condensation, and the temperature detected by the temperature sensor 115 is guided to a predetermined temperature. Therefore, it is possible to reduce power consumption during defrosting and reduce power peaks without using a heater.

Thereafter, the refrigerant condensed while heating the evaporator 106 exits from the evaporator heating outlet 146, is depressurized again by the third throttle 129, and passes through the multistage expansion circuit 130 to the heating side evaporator at point k. 131.

The evaporation temperature of the refrigerant in the heating side evaporator 131 is adjusted by the amount of pressure reduction by the third throttle 129 and the rotation speed of the compressor 105, and is normally maintained at -25 to -10°C. A heating side evaporator fan 134 is arranged above the heating side evaporator 131 and is housed in the refrigerator compartment duct 113.

Generally, when heating the evaporator 106 using the defrosting path 152, it is necessary to take away from the heating side evaporator 131 an amount of cooling heat equivalent to the amount of heating of the evaporator 106. On the other hand, since the heating amount of the evaporator 106 is two to three times the waste heat of the compressor 105, etc., the evaporator 106 can be efficiently defrosted.

This time, while the heating side evaporator 131 removes heat from inside the refrigerator compartment 101, the heating side evaporator fan 134 can cool the inside of the refrigerator compartment 101 using the refrigerator compartment duct 113 during cooling. , the compressor 105 is stopped and defrosting is performed by the defrosting heater 120, but in this embodiment, defrosting is possible without stopping cooling due to stopping the operation of the compressor 105.

The refrigerant that has passed through the heating side evaporator 131 then returns to the compressor 105 at point L via the heating side suction pipe 132 and the suction pipe 126.

The third throttle 129 is made of a capillary tube with an inner diameter of 0.5 to 1 mm, and the multistage expansion circuit 130, which is a secondary capillary, is made of a small diameter tube with an inner diameter of 1.5 to 3 mm. By gradually increasing the thickness of the refrigerant piping (not shown) with a diameter of 6 to 9 mm, it is possible to suppress the generation of abnormal noise caused by rapid refrigerant expansion and speed changes, and by reducing the outside surface area of the pipe, it is possible to reduce the thickness of the pipe. This reduces the amount of frost buildup and reduces problems such as the outflow of condensed water.

Therefore, most of the third aperture 129 is buried in the heat insulating material (not shown) constituting the housing 100b of the refrigerator 100, and the connecting portion between a part of the multistage expansion circuit 130 and the heating side evaporator 131 is It is desirable to limit the exposure to the area around the refrigerator compartment duct 113 in the refrigerator compartment 101.

[1-2. motion]
The operation and effect of the refrigerator 100 according to the first embodiment configured as above will be explained below.

The operation of refrigerator 100 during a defrosting operation in which evaporator 106 is defrosted will be described using FIG. 7 . FIG. 7 shows that time progresses from left to right.

“ON” of the compressor 105 indicates that the compressor 105 is operating. Further, "OFF" of the compressor 105 indicates that the compressor 105 is stopped.

“ON” of the first machine room fan 116 indicates that the first machine room fan 116 is operating. Further, "OFF" of the first machine room fan 116 indicates that the first machine room fan 116 is stopped.

"Cooling" of the flow path switching valve 122 indicates that the flow path from the flow path switching valve 122 to the cooling path 151 is open, and the flow path from the flow path switching valve 122 to the defrosting path 152 is closed. . In addition, in "defrosting" of the flow path switching valve 122, the flow path from the flow path switching valve 122 to the defrosting path 152 is opened, and the flow path from the flow path switching valve 122 to the cooling path 151 is closed. Show that. Further, when the flow path switching valve 122 is “fully closed”, both the flow path from the flow path switching valve 122 to the cooling path 151 and the flow path from the flow path switching valve 122 to the defrosting path 152 are blocked. Show that there is.

“ON” of the cooling fan 111 indicates that the cooling fan 111 is operating. Further, "OFF" of the cooling fan 111 indicates that the cooling fan 111 is stopped.

"Open" of the freezer compartment damper 112 indicates that the freezer compartment damper 112 is open. Moreover, "occlusion" of the freezer compartment damper 112 indicates that the freezer compartment damper 112 is blocked.

"Open" of the refrigerator compartment damper 114 indicates that the refrigerator compartment damper 114 is open. Moreover, "occlusion" of the refrigerator compartment damper 114 indicates that the refrigerator compartment damper 114 is closed.

“ON” of the heating side evaporator fan 134 indicates that the heating side evaporator fan 134 is operating. Further, "OFF" of the heating side evaporator fan 134 indicates that the heating side evaporator fan 134 is stopped.

“ON” of the defrosting heater 120 indicates that the defrosting heater 120 is energized and defrosting is being performed by the defrosting heater 120. On the other hand, OFF of the defrosting heater 120 indicates that power supply to the defrosting heater 120 is stopped and defrosting by the defrosting heater 120 is not performed.

Timing T1 is the timing at which refrigerator 100 shifts from normal cooling operation to defrosting operation. The transition timing to the defrosting operation is, for example, when the accumulated operating time of the compressor 105 reaches a predetermined time from the previous defrosting timing, or when a certain time has elapsed. At timing T1, it is assumed that the temperature of the freezer compartment 102 will rise due to defrosting, so the refrigerator 100 opens the freezer compartment damper 112 for a while to increase the temperature of the freezer compartment 102 before starting defrosting. decrease.

Next, at timing T2, the state of the flow path switching valve 122 is switched from "cooling" to "defrosting". By switching the refrigerant flow path from the cooling path 151 to the defrosting path 152 at timing T2, the refrigerant that has passed through the first heat exchange section 128 and been vaporized beyond the saturated vapor line is supplied to the evaporator 106. The air is heated by the latent heat generated by condensation in the evaporator 106, and defrosting is started.

Further, at timing T2, the state of the freezer compartment damper 112 is switched from "open" to "closed", and the state of the refrigerator compartment damper 114 is switched from "closed" to "open". This is because the refrigerant remaining in the piping of the evaporator 106 is evaporated and returned to the compressor 105 by heating the evaporator 106 from the air side while circulating the air inside the refrigerator compartment 101 .

Further, at timing T2, the state of the heating side evaporator fan 134 changes from "OFF" to "ON". This not only circulates the cold air generated by the evaporation of the internal refrigerant in the evaporator 106 into the refrigerator compartment 101, but also increases the air volume compared to the cooling fan 111 alone, so that the evaporator 106 evaporates more quickly. The refrigerant remaining in the container cooling pipe 137 can be evaporated and returned to the compressor 105. Furthermore, from timing T2, the refrigerant starts to evaporate in the heating side evaporator 131, so cold air is generated by the refrigerant, and by circulating this cold air into the refrigerator compartment 101, the temperature of the refrigerator compartment 101 increases during defrosting. Suppression is being carried out.

Next, at timing T3, the state of the cooling fan 111 is switched from "ON" to "OFF", and the state of the refrigerator compartment damper 114 is switched from "open" to "closed". The reason why the refrigerator compartment damper 114 is closed and the cooling fan 111 is stopped is when the refrigerant remaining in the evaporator cooling pipe 137 of the evaporator 106 evaporates and the temperature of the evaporator 106 approaches the air temperature of the refrigerator compartment 101. This is because heat exchange becomes difficult.

Then, the state of the defrosting heater 120 is switched from "OFF" to "ON". By starting energizing the defrosting heater 120, defrosting is also started from the lower side of the evaporator 106. At this time, the compressor 105 is "ON" and the defrosting heater 120 is also "ON".

Due to the latent heat of condensation of the refrigerant flowing through the evaporator heating pipe 138, the capacity of the defrosting heater 120 can be reduced, and in this embodiment, the applied voltage is lowered from 100V (180W) to 50V (45W). The capacity of the defrosting heater 120 can be changed depending on the outside temperature, operating conditions, and frost adhesion state.

In this embodiment, for example, when the outside temperature is 32° C., the power of the compressor 105 is about 45 W due to heating using the latent heat of condensation of the refrigerant, and the capacity of the defrosting heater 120 is about 45 W, so the total power is about 90 W. is the power used during defrosting. This is half of 180W when using only the defrosting heater 120. Therefore, it is possible to reduce power consumption during defrosting and reduce power peaks.

Next, at timing T4, the state of the freezer compartment damper 112 is switched from "closed" to "open". This is because although the air in the cooling chamber 117 is heated during defrosting, there is no convection, so the heat stagnates, resulting in a temperature difference between the upper and lower portions of the evaporator 106. Therefore, by setting the state of the freezer compartment damper 112 to "open", a small amount of convection is caused from the interior of the freezer compartment 102, where the temperature is low, to the interior of the cooling compartment 117, where the temperature is high during defrosting, thereby improving the defrosting efficiency. It is increasing. In this embodiment, it is set as "open", but it may be "slightly opened" as long as a small amount of convection is generated.

Timing T5 is the timing when the temperature detected by temperature sensor 115 reaches a predetermined temperature, and is the timing at which refrigerator 100 determines that defrosting of evaporator 106 has been completed. At timing T5, the state of the compressor 105 is switched from "ON" to "OFF", and the state of the first machine room fan 116 is also switched from "ON" to "OFF". Further, the state of the defrosting heater 120 is switched from "ON" to "OFF".

As a result, the operation of the defrosting path 152 is stopped, and this state is maintained for a predetermined period of time from timing T5 to timing T7 until the pressure inside the defrosting path 152 is approximately equalized. On the other hand, the heating side evaporator fan 134 maintains the "ON" state for a predetermined period of time from timing T5 to timing T6.

At this time, since the refrigerator compartment 101 is in a cooling state, overcooling in the refrigerator compartment 101 can be suppressed by adjusting the time from timing T5 to timing T6. In that case, the process moves to timing T6 at the timing when the temperature detected by the refrigerator compartment temperature sensor disposed in the refrigerator compartment 101 reaches a predetermined temperature. The refrigerator compartment temperature sensor uses the same sensor that controls opening and closing of the refrigerator compartment damper 114 during cooling operation.

Next, at timing T6, the state of the heating side evaporator fan 134 is switched from "ON" to "OFF".

Next, at timing T7, the state of the flow path switching valve 122 is switched from "defrosting" to "cooling", and the state is maintained for a predetermined time until the pressure in the defrosting path 152 and the cooling path 151 are approximately equalized, and then, at timing At T8, the state of the compressor 105 is switched from "OFF" to "ON" and the operation of the cooling path 151 is started. Here, the reason why the predetermined period of time is maintained is to prevent the refrigerant from suddenly flowing when the flow path switching valve 122 is switched and causing unpleasant noise.

Furthermore, the reason why the heating side evaporator fan 134 is turned on from timing T5 to timing T6 and from timing T8 to timing T9 is because the heating side evaporator fan 134 is turned on because it is connected to the evaporator 106 via the suction pipe 126. This is to quickly raise the temperature of the hot side evaporator 131.

At timing T8, the compressor 105 starts operating the cooling path 151, and after waiting for a predetermined time until timing T9 when the temperature of the evaporator 106 has sufficiently decreased, the state of the heating side evaporator fan 134 changes from "ON" to "OFF". ”, the state of the cooling fan 111 is switched from “OFF” to “ON”.

At timing T9, refrigerator 100 shifts from defrosting operation to cooling operation.

Next, the process executed by refrigerator 100 is shown in the flowchart of FIG. Each step shown in the flowchart of FIG. 8 is realized by the CPU (not shown) of refrigerator 100 executing a control program stored in a memory (not shown) such as a ROM of refrigerator 100. Although the CPU and ROM are not shown in FIG. 1, a control board composed of the CPU and ROM is housed in the top surface 100d of the refrigerator 100.

In step 401, the CPU determines whether to perform defrosting. In this embodiment, evaporation occurs when the cumulative operating time of the compressor 105 reaches a predetermined time, after a predetermined time has elapsed since the end of the previous defrosting, or due to outside air temperature, opening/closing of the doors 101a and 102a, etc. When it is thought that there is a large amount of frost on the container 106, the CPU determines that defrosting should be performed, and the process proceeds to step 402. This operation corresponds to timing T2 in FIG.

Next, in step 402, the CPU switches the refrigerant flow path to the defrosting path 152. The CPU controls the flow path switching valve 122 to switch the refrigerant flow path from the cooling path 151 to the defrosting path 152. By switching the refrigerant flow path to the defrosting path 152, the refrigerant heated in the first heat exchange section 128 is supplied to the evaporator 106, and the evaporator 106 is defrosted. Note that defrosting by the defrosting path 152 is performed from above the evaporator 106. This operation corresponds to timings T2 to T5 in FIG.

Next, in step 403, the CPU starts the operation of the defrosting heater 120. The evaporator 106 is defrosted when the CPU starts energizing the defrosting heater 120 . Note that defrosting by the defrosting heater 120 is performed from below the evaporator 106. This operation corresponds to timings T3 to T5 in FIG.

Next, in step 404, the CPU determines whether defrosting has been completed. In this embodiment, when the temperature detected by temperature sensor 115 reaches a predetermined temperature, the CPU determines that defrosting has been completed, and the CPU stops the operation of compressor 105 and turns on defrost heater 120. Stop energizing. Processing proceeds to step 405. This operation corresponds to timing T5 in FIG.

Next, in step 405, the CPU stops the operation of the compressor 105 and stops the power supply to the defrosting heater 120. After waiting for a predetermined period of time, the operation of step 406 is started for cooling operation.

Next, in step 406, the CPU controls the flow path switching valve 122 to switch the refrigerant flow path from the defrosting path 152 to the cooling path 151 in order to perform a cooling operation after defrosting. After waiting for a predetermined time, the compressor 105 and the heating side evaporator fan 134 are driven first.

After that, the CPU stops the heating side evaporator fan 134 and starts the cooling operation of the refrigerator 100 by driving the cooling fan 111 to start blowing air. This operation corresponds to timings T7 to T9 in FIG.

In this embodiment, each step shown in the flowchart of FIG. 8 has been described as being implemented by one CPU, but it may be implemented by multiple CPUs working together.

[1-3. Effects, etc.]
As described above, in this embodiment, refrigerator 100 includes refrigeration cycle 150 that includes at least compressor 105, first condenser 107, second condenser 123, and evaporator 106. The refrigeration cycle 150 is downstream of the first condenser 107 and includes a cooling path 151 that supplies refrigerant to the evaporator 106 to generate cold air, and a cooling path 151 that heats the refrigerant and supplies the heated refrigerant to the evaporator 106. The defrosting path 152 is branched into a defrosting path 152 that performs defrosting.

The refrigerant flowing through the cooling path 151 is supplied to the evaporator 106 after passing through the second condenser 123, and the refrigerant flowing through the defrosting path 152 is supplied from the compressor 105 to the first condenser 107. The refrigerant is heated by exchanging heat with the defrosting path 152 and heats the evaporator 106 that is thermally coupled to the defrosting path 152. After being evaporated in the hot side evaporator 131, it is returned to the compressor 105.

As described above, one refrigeration cycle 150 includes a defrosting path 152 that defrosts the cooling path 151 and the evaporator 106 by heating them with the heat of condensation of the refrigerant, even when the refrigerant state is in the two-phase region. By branching into a cooling path 151 and a defrosting path 152 on the downstream side of the first condenser 107, which is close to the liquid phase, and switching to the defrosting path 152 side during defrosting, the flow is generated from the flow path switching valve 122 and the evaporator 106. It is possible to suppress the flowing sound that occurs.

When the refrigerant in the condensing pipe in the refrigeration cycle 150 is close to the saturated liquid line, a portion of the high temperature and high pressure refrigerant discharged from the compressor 105 is liquefied and the volume of the refrigerant is reduced. Therefore, in the two-phase region, the flow rate on the liquid phase side is about 1/40 of that on the gas phase side, and this is because the flow rate of the refrigerant flowing through the flow path switching valve 122 is slow. Since the refrigerant discharged from the compressor 105 does not directly flow through the flow path switching valve 122, it is possible to suppress the generation of noise that the user feels uncomfortable.

Furthermore, since the refrigerant flowing through the defrosting path 152 is heated by the high temperature refrigerant discharged from the compressor 105 in the first heat exchange section 128 after the flow path switching valve 122, the state of the refrigerant changes to the liquid phase. It is vaporized from the nearby two-phase region. In this state, the evaporator 106 is heated by utilizing the latent heat of condensation. In the refrigeration cycle 150, the heat from the compressor 105 and condenser that radiates heat can be used for defrosting.

This makes it possible to utilize not only the sensible heat of the refrigerant but also the latent heat in the two-phase region, which has a larger calorific value than the sensible heat. A large amount of heat can be used for heating compared to when used for defrosting. Approximately three times the efficiency of the waste heat of the compressor 105 can be obtained.

In this embodiment, since the evaporator heating pipe 138 is attached directly and closely around the evaporator 106, the temperature can be raised uniformly, compared to an indirect defrosting heater. It is also possible to defrost with high efficiency. That is, since the defrosting efficiency also increases, it is possible to obtain an efficiency three times higher than the efficiency of the defrosting heater 120, which is 1.

Therefore, if the defrosting heater 120 is 180 W as an input to the refrigerator 100, defrosting using the defrosting path 152 of this embodiment can achieve the same power with 60 W, thereby saving power. can be achieved. Further, the power peak of the refrigerator 100 occurs during defrosting using the defrosting heater 120, and the power peak during defrosting can also be suppressed by this embodiment.

In other words, since it is possible to suppress fluctuations in the power used, it is possible to adjust the power load, for example by controlling the defrosting timing, according to fluctuations in power demand in the summer or the power used by other devices in the home, which is environmentally friendly. You can also make a contribution.

In the current refrigerator, the defrosting heater 120 substantially heats not only the evaporator 106 but also the inside of the cooling chamber 117 during defrosting. This is due to the radiant heat from the defrosting heater 120, but in this embodiment as well, when defrosting using the defrosting path 152, the low-power defrosting heater 120 is simultaneously energized in a hybrid manner, so that the evaporator The defrosting time of the cooling chamber 117 can be shortened, and the inside of the cooling chamber 117 can also be defrosted.

As a result, the time saving effect is large even after subtracting the additional power of the defrosting heater 120, so further energy saving effects can be obtained.The shortening of the defrosting time also shortens the temperature rise time inside the refrigerator. Therefore, the amount of electricity involved in recooling after defrosting can also be reduced. Furthermore, since the temperature rise in the refrigerator compartment 101 and the freezer compartment 102 is also suppressed, the temperature rise of the stored food is also suppressed, and deterioration in freshness is also effectively suppressed.

Further, the heating side evaporator 131 is arranged in the refrigeration temperature zone. During defrosting, the temperature of the heating side evaporator 131 in the refrigerator compartment duct 113 is controlled by the rotation speed of the compressor 105 etc. so that the temperature of the heating side evaporator 131 in the refrigerator compartment duct 113 is maintained at -25 to -10°C. This temperature is equivalent to the temperature of the cold air blown from the evaporator 106 during the cooling operation. Therefore, the inside of the refrigerator compartment 101 can be cooled using the refrigerator compartment duct 113 during cooling by the heating side evaporator fan 134 located above.

As a result, in the case of defrosting a general refrigerator, since the compressor 105 is stopped during defrosting, cooling may be stopped for about 60 minutes when the amount of frost is large. In that case, the temperature of the refrigerator compartment 101, which is usually about 4°C depending on the outside temperature, rises to over 10°C. Although many fresh foods that are susceptible to temperature fluctuations and foods that require refrigeration (below 10° C.) are stored in the refrigerator compartment 101, in this embodiment, the compressor 105 can be stored without stopping the compressor 105. Since defrosting can be performed while cooling the refrigerator compartment 101, the temperature inside the refrigerator does not rise and can be maintained at a constant temperature even during defrosting.

That is, during the cooling operation, the internal temperature of the refrigerator compartment 101 fluctuates due to the refrigerator compartment temperature sensor and the refrigerator compartment damper 114, but is kept at a constant temperature of approximately 4°C. By doing so, the temperature can be maintained at a constant temperature, and the internal temperature of the refrigerator compartment 101, which is approximately 4° C., can be maintained, so deterioration of food freshness can be suppressed.

Further, the operation of the heating side evaporator fan 134 is controlled during defrosting. This not only cools only the area around the heating side evaporator 131, but also prevents food from freezing due to overcooling, and also cools the entire interior of the refrigerator, which improves temperature distribution within the refrigerator and improves quality. I can do it.

Further, the operation of the heating side evaporator fan 134 is controlled according to the temperature detected by the refrigerator compartment temperature sensor during defrosting. Specifically, the heating side evaporator fan 134 is stopped and its rotation speed is increased or decreased.

In this embodiment, the operation of the heating side evaporator fan 134 is stopped when the temperature is below the threshold temperature between timing T2 and timing T6 in FIG. The threshold temperature is 0°C. This prevents the internal temperature of the refrigerator compartment 101 from becoming too cold.

At this time, there is a concern that liquid may back up into the compressor 105, but this can be avoided by using an evaporator accumulator (not shown) after the heating side evaporator 131.

In addition, in this embodiment, since the inside of the refrigerator compartment 101 can be cooled during defrosting, the compressor 105 is stopped and the defrosting heater 120 is heated during recooling after defrosting. Even in comparison, the required cooling capacity is reduced. Since the temperature of the refrigerator compartment 101 is maintained at a constant temperature during defrosting, recooling after defrosting only needs to be done in the freezing compartment 102, which saves power by reducing the operating speed of the compressor 105 and shortening the cooling time. is possible.

(Embodiment 2)
Embodiment 2 will be described below with reference to FIGS. 9 and 10.

[2-1. composition]
In FIG. 9, a refrigerator 100 according to the present embodiment has a two-way valve 125 provided between a second condenser 123 and a first throttle 124 in addition to the configuration of the refrigerator 100 according to the first embodiment. There is.

[2-2. motion]
The operation and effect of the defrosting operation for defrosting the evaporator 106 of the refrigerator 100 in this embodiment configured as described above will be described below with reference to FIG.

FIG. 10 shows that time progresses from left to right.

“Open” of the two-way valve 125 indicates that the two-way valve 125 is open. Moreover, "occlusion" of the two-way valve 125 indicates that the two-way valve 125 is closed.

Timing T1 is the timing at which refrigerator 100 shifts from normal cooling operation to defrosting operation. The transition timing to the defrosting operation is, for example, when the accumulated operating time of the compressor 105 reaches a predetermined time from the previous defrosting timing, or when a certain time has elapsed. At timing T1, it is assumed that the temperature of the freezer compartment 102 increases due to defrosting, so the refrigerator 100 opens the freezer compartment damper 112 for a while to increase the temperature of the freezer compartment 102 before starting defrosting. Reduce temperature.

At timing T2, the state of the flow path switching valve 122 is switched from "cooling" to "defrosting". Further, at timing T2, the state of the freezer compartment damper 112 is switched from "open" to "closed", and the state of the refrigerator compartment damper 114 is switched from "closed" to "open".

Further, at timing T2, the state of the heating side evaporator fan 134 changes from "OFF" to "ON". As a result, the refrigerant is condensed in the evaporator 106 and is heated by the latent heat generated, thereby starting defrosting, and cooling the refrigerator compartment 101 while evaporating the refrigerant remaining in the evaporator cooling pipe 137 of the evaporator 106. This suppresses the temperature increase in the refrigerator compartment 101 during defrosting and prevents liquid backing into the compressor 105.

At this timing T2, the state of the two-way valve 125 is switched from "open" to "closed". By closing the two-way valve 125 at timing T2, the inlet 123a and outlet 123b of the second condenser 123 are closed, and the refrigerant is stored.

As a result, the amount of refrigerant can be adjusted to an appropriate amount for defrosting operation, and by setting the dryness of the first condenser 107 to 0 to 50%, the refrigerant flow rate of the flow path switching valve 122 is suppressed and the refrigerant flow is reduced. It can prevent the generation of sound. This is because when the dryness of the first condenser 107 exceeds 50%, the refrigerant flow noise in the flow path switching valve 122 increases as the refrigerant flow rate increases.

Furthermore, when the degree of dryness of the first condenser 107 falls below 0%, that is, it becomes a supercooled state, the enthalpy of the refrigerant is lost, and the refrigerant is insufficiently vaporized in the first heat exchange section 128. A problem occurs in which the amount of heat used to defrost is reduced.

Then, from timing T5 to timing T6, the state of the compressor 105 is switched from "ON" to "OFF", and the state of the first machine room fan 116 is also switched from "ON" to "OFF". Further, the state of the heating side evaporator fan 134 is switched from "ON" to "OFF", and the state of the defrosting heater 120 is also switched from "ON" to "OFF". As a result, the operation of the defrosting path 152 is stopped.

Thereafter, at timing T7, the state of the flow path switching valve 122 is switched from "defrosting" to "cooling", and the state of the two-way valve 125 is switched from "closed" to "open". Note that the reason for maintaining the predetermined time period from timing T5 to timing T7 until the pressure in the defrosting path 152 is approximately equalized is to avoid unpleasant sensations caused by sudden refrigerant flow when the flow path switching valve 122 or the two-way valve 125 is switched. This is to prevent noise from being generated.

Furthermore, the reason why the heating side evaporator fan 134 is turned on from timing T5 to timing T6 and from timing T8 to timing T9 is because the heating side evaporator fan 134 is turned on because it is connected to the evaporator 106 via the suction pipe 126. This is to quickly raise the temperature of the hot side evaporator 131.

[2-3. Effects, etc.]
As described above, in the present embodiment, the refrigerator 100 closes the two-way valve 125 provided between the second condenser 123 and the first throttle 124 when performing the defrosting operation. The refrigerant is stored in the second condenser 123, and the dryness of the first condenser 107 is set to 0 to 50%.

As a result, the flow rate of the refrigerant can be controlled to further suppress the flow noise generated from the flow path switching valve 122 and the evaporator 106, and since the refrigerant is stored in the second condenser 123, the compressor There is no concern about liquid backing up to 105.

Note that in this embodiment, the flow path switching valve 122 and the two-way valve 125 are switched simultaneously at timing T2, but the two-way valve is switched after a predetermined time after switching the flow path switching valve 122 from "cooling" to "defrosting". 125 from "open" to "closed" can reduce the amount of refrigerant stored in the second condenser 123, and after a predetermined period of time after switching the two-way valve 125 from "open" to "closed" When the switching valve 122 is switched from "cooling" to "defrosting", the amount of refrigerant stored in the second condenser 123 can be increased, so the amount of refrigerant can be adjusted to the optimum amount according to various conditions such as outside temperature. be able to.

(Other embodiments)
As mentioned above, Embodiments 1 and 2 have been described as examples of the technology disclosed in this application. However, the technology in the present disclosure is not limited to this, and can also be applied to embodiments in which changes, replacements, additions, omissions, etc. are made. Furthermore, it is also possible to create a new embodiment by combining the components described in the first and second embodiments.

Therefore, other embodiments will be illustrated below.

In the first and second embodiments, the heat exchange method of the first heat exchange section 128 was performed by soldering from the viewpoint of cost and simplicity. It can also be used as a figure-8-shaped piping or as a double piping in which a piping through which refrigerant discharged from the second throttle 127 flows is arranged inside the piping that supplies the refrigerant from the compressor 105 to the first condenser 107. good.

The method of heat exchange is not limited to soldering, but since the purpose is to vaporize the refrigerant to utilize the latent heat of condensation of the refrigerant, there is also a method of communicating the refrigerant with the inside of the compressor 105 to vaporize it. Since the temperature is higher than the condensation temperature, a large amount of heat can be received, and the heating efficiency in the evaporator heating pipe 138 is improved.

Furthermore, the compressor 105 is generally a lump of iron and weighs about 6 to 7 kg. By exchanging heat with the compressor 105, the sensible heat corresponding to this weight can also be used, so the same heating efficiency can be obtained with a short heat exchange length, and a compact configuration is possible.

Also, exchanging heat with the condenser is highly effective. The capacity adjustment condenser 133 is of a fin-and-tube type similar to the evaporator 106, and a part of the internal piping is used as the defrosting path 152, so that heat can be exchanged through the fins. By arranging the piping for the cooling path 151 and the piping for the defrosting path 152 in one condenser, efficient heat exchange can be achieved.

By opposing the flow of refrigerant in each pipe, the temperature difference becomes large and heat can be exchanged efficiently. Since the inlet of the capacity adjustment condenser 133 is in the gas phase region before receiving pressure loss in the piping during the condensation process, the enthalpy at point h in FIG. 4B becomes high, and the heating enthalpy at point i also becomes high. The capacity increases and the efficiency of defrosting improves.

Note that in the first and second embodiments, small diameter tubes are used for the second aperture 127 and the third aperture 129. The inner diameter is approximately 0.5 to 1.0 mm, and the length is approximately 2000 mm. Of course, an expansion valve that can control the flow rate linearly or a fixed hole valve that can control the flow rate in steps may also be used. This time, by adopting a configuration using small diameter tubes, the configuration is inexpensive and easy, and product costs can be held down by reducing manufacturing costs and process man-hours.

Furthermore, by making the piping at the inlet of the first heat exchanger 128 into a condensed tube shape and substituting the small diameter tube for the second throttle 127, the number of connections and parts can be reduced, resulting in further cost benefits. Occur.

Furthermore, in the first and second embodiments, the fins 139 forming the evaporator 106 are split fins. In the case of divided fins, the number of fins increases, and therefore, the number of steps for attaching the fins 139 in the manufacturing process of the evaporator 106 is required.

Therefore, fins 139 that are integrated in the vertical direction may be used. As a result, the number of fins 139 attached to the evaporator 106 can be reduced, so it is possible to reduce costs by improving productivity by reducing the number of man-hours.

In this case, if the fins 139 are notched at the attachment portion of the evaporator heating pipe 138, the adhesion to the evaporator heating pipe 138 will be improved and the heat exchange efficiency will be improved.

In addition, the evaporator cooling pipe 137 of the evaporator 106 in the first and second embodiments described above is an unprocessed pipe called a bare pipe. Therefore, in order to improve the heat transfer coefficient within the tube, for example, a grooved tube may be used. Some grooved tubes include straight grooves and spiral grooves, and by using grooved tubes, the performance of the evaporator 106 can be improved, resulting in further energy savings.

Note that the evaporator cooling pipe 137 of the evaporator 106 in the first and second embodiments is made of aluminum. Aluminum is often used to reduce costs due to the recent rise in material costs, but copper may also be used. In this case, since the thermal conductivity is improved, the efficiency of heat exchange between the inside and outside of the pipe is improved, resulting in further energy savings.

Further, in the first and second embodiments, the heating side evaporator 131 is of the fin-and-tube type similar to the evaporator 106, but the heating side evaporator 131 may be combined with a cold storage material. For example, it may be an insert molded structure made of resin, an external unit, or a microchannel evaporator.

By filling the portion in contact with the heating side evaporator 131 and the inside of the microchannel with the cold storage material, the cold heat generated by the heating side evaporator 131 can be stored in the cold storage material. As a result, the refrigerating room 101 can be cooled with the cold storage material after defrosting is completed, resulting in further energy savings. Further, when the outside temperature of the refrigerator compartment 101 is low and the influence of heat from the outside is small, the temperature of the refrigerator compartment 101 cools down quickly during the defrosting described in the above embodiment.

For example, if the temperature of the refrigerator compartment 101 falls below a threshold value, the number of revolutions of the heating side evaporator fan 134 is reduced or stopped, the number of revolutions of the compressor 105 is reduced, etc. However, this cold energy can be stored using a cold storage material. After defrosting, it can be used to cool the refrigerator compartment 101.

Further, in the first and second embodiments described above, heat exchange can also be performed between the small diameter pipe of the third throttle 129 and the heating side suction pipe 132 which is the suction path to the compressor 105. This not only evaporates the liquid refrigerant that has not been completely evaporated in the heating side evaporator 131 and prevents the liquid refrigerant from entering the suction pipe 126, but also makes it possible to prevent the change from point j to point k in FIG. - will change diagonally to the left. Since this amount of change corresponds to the enthalpy difference from the outlet of the heating side evaporator 131 to the L point, the enthalpy difference from the k point to the L point becomes large, and the refrigeration effect in the defrosting path 152 becomes large. Therefore, the cooling capacity for the refrigerator compartment 101 is improved.

The present disclosure can suppress the generation of sounds that are unpleasant to users and reduce the amount of recooling after defrosting, so it can be applied to household refrigerators and freezers, and commercial refrigerators and freezers.

100 Refrigerator 100a Partition 100b Housing 100c Outer wall surface 100d Top surface 101 Refrigerator room 101a, 102a Door 102 Freezer room 103 First machine room 104 Second machine room 105 Compressor 106 Evaporator 107 First condenser 108 Partition wall 109 Second machine room fan 110 Evaporation dish 111 Cooling fan 112 Freezer damper 113 Refrigerator duct 114 Refrigerator damper 115 Temperature sensor 116 First machine room fan 117 Cooling compartment 119 Refrigerator return duct 120 Defrost heater 121 Dryer 122 Flow Path switching valve 123 Second condenser 123a Inlet 123b Outlet 124 First throttle 125 Two-way valve 126 Suction pipe 127 Second throttle 128 First heat exchange section 128a Inlet section 128b Outlet section 129 Third throttle 130 Multi-stage Expansion circuit 131 Heating side evaporator 132 Heating side suction pipe 133 Capacity adjustment condenser 134 Heating side evaporator fan 137 Evaporator cooling pipe 138 Evaporator heating pipe 139 Fin 140 End plate 141 Evaporator accumulator 143 Evaporator Cooling inlet 144 Evaporator cooling outlet 145 Evaporator heating inlet 146 Evaporator heating outlet 150 Refrigeration cycle 151 Cooling path 152 Defrosting path

Claims (4)

A refrigerator having a refrigeration cycle including at least a compressor, a first condenser, a second condenser, and an evaporator,
The refrigeration cycle is
downstream of the first condenser, a cooling path for supplying refrigerant to the evaporator to generate cold air;
a defrosting path that heats a refrigerant and supplies the heated refrigerant to the evaporator for defrosting;
The refrigerant flowing through the cooling path is supplied to the evaporator after passing through the second condenser,
The refrigerant flowing through the defrosting path is heated by exchanging heat with the path through which the refrigerant is supplied from the compressor to the first condenser,
The refrigerant that heats the evaporator, which is thermally connected to the defrosting path, and radiates heat in the defrosting path is evaporated in a heating side evaporator provided downstream of the evaporator, and then supplied to the compressor. In the return configuration, a heating side evaporator fan is disposed above the heating side evaporator, and the heating side evaporator fan is operated during defrosting.
A refrigerator characterized by: The refrigerator according to claim 1, wherein the heating side evaporator is arranged in a refrigeration temperature zone. A refrigerating room temperature sensor is provided to detect the temperature of the refrigerating room, and when the refrigerating room temperature sensor in the refrigerating temperature range during defrosting is below a threshold temperature, the operation of the heating side evaporator fan is stopped. The refrigerator according to claim 1 or 2 . The refrigerator according to any one of claims 1 to 3, characterized in that the heating side evaporator is combined with a cold storage material.