JP5436626B2 - refrigerator - Google Patents

Description

  The present invention relates to a refrigerator, and more particularly to melting of frost attached to a cooler or the like.

  In the refrigerator, a cooling operation is performed in order to cool a cooling object such as food in a storage room (for example, a refrigerator room, a freezer room, a vegetable room, etc.). At this time, air in the storage room is circulated by the internal fan, the air is cooled by a cooler, and sent out to the storage room, thereby cooling food stored in the storage room. Here, when the outside air flows into the storage chamber by opening and closing the door of the refrigerator, or the moisture of the food in the storage chamber evaporates into the storage chamber, the absolute humidity of the air in the storage chamber increases. When the absolute humidity rises, moisture in the storage room air sublimates on the surface of the cooler, and frost adheres to the cooler. For this reason, for example, when the cooling operation is performed for about one day, the cooler may be covered with frost.

  When frost adheres to the cooler, the airflow resistance of the cooler increases, so the air volume of the air sent into the storage chamber decreases. Moreover, the thermal resistance between the refrigerant flowing in the cooler and the air in the storage room increases, and the refrigeration capacity decreases. Therefore, in the refrigerator, for example, defrosting is performed every predetermined time (for example, once a day) to suppress an increase in ventilation resistance and an increase in thermal resistance of the cooler.

  In order to defrost the refrigerator cooler, for example, a heater is attached in the vicinity of the cooler, and the radiant heat of the heater and the ambient air warmed by the heater are convected to indirectly heat and melt the frost of the cooler. A refrigerator having a function has been proposed. However, in such a refrigerator, since the rate at which the heat of the heater leaks into the storage chamber increases, the temperature in the storage chamber rises during defrosting, which may reduce food quality.

  For this reason, a refrigerator having a function of defrosting the cooler has been proposed in which the cooler is directly heated by a heating source such as a heater to melt the frost in the cooler. In addition, in order to suppress power consumption due to energization of the heater, a refrigerant circuit (hot gas defrosting circuit) that can supply the refrigerant compressed to a high temperature and high pressure with a compressor to the cooler to directly heat and melt the frost ) Has also been proposed. However, the configuration in which the cooler is directly heated, such as hot gas defrosting, is easily slid onto the tray without melting the frost. For this reason, the frost that could not be melted may block the drain hole of the tray.

  Then, the refrigerator which made the tray (henceforth a bypass piping) contact the tray through which the high-temperature refrigerant | coolant flows among piping which comprises a hot gas defrost circuit is proposed (for example, refer patent document 1). The technique described in Patent Document 1 transmits heat of the refrigerant flowing through the bypass pipe to the tray through the bypass pipe, and heats the frost that has slipped onto the tray to melt the frost. Moreover, the refrigerator which arrange | positioned the heater as a heating means to heat a tray directly in a hot gas defrost circuit is also proposed (for example, refer patent document 2).

JP 2007-218537 A (FIG. 1) Japanese Patent Laying-Open No. 2005-249254 (FIG. 1)

  In the refrigerator described in Patent Document 1, the defrost release sensor is attached to the pipe immediately downstream of the cooler, and when the temperature in the pipe immediately downstream becomes higher than 3 ° C., the frost attached to the cooler is completely melted. As a result, the hot gas defrosting has been completed. However, after the frost slips from the cooler during hot gas defrosting, the temperature of the cooler rises in a short time. For this reason, although the frost which slipped from the cooler to the tray is not melted, the defrosting operation may be terminated, and the slipped frost may remain on the tray.

  In order to prevent such a defrosting operation from occurring quickly, if the operation time is made longer than necessary, the power consumption during defrosting is increased. In addition, the temperature of the air in the storage room is greatly increased, which may damage food in the storage room. Furthermore, there is a possibility that the time for the operation for cooling the storage chamber to the set temperature after defrosting (hereinafter referred to as pull-down operation) is lengthened and the power consumption during pull-down is increased.

  For this reason, for example, in the refrigerator described in Patent Document 2, the first temperature detection means (hereinafter referred to as a first thermistor) is used as a cooler, and the second temperature detection means (hereinafter referred to as a second thermistor). ) Is provided on the tray, and it is confirmed that the temperature detected by the second thermistor is close to 0 ° C. due to the frost sliding down from the cooler to the tray. When the detected temperature of the second thermistor becomes equal to or higher than the set temperature, the defrosting operation is finished assuming that the frost on the cooler and the tray is completely melted.

  However, the refrigerator described in Patent Document 2 has a small amount of frost attached to the cooler (amount of frost formation) and a small amount (or no) of frost sliding from the cooler to the tray during the defrosting operation. The detected temperature of the second thermistor does not become around 0 ° C., and the heater is not energized. For this reason, because the tray is not heated and the temperature detected by the second thermistor does not reach the set temperature, the defrosting operation does not end indefinitely, the internal temperature rises, and in the worst case, the food is damaged. There was a point.

  Patent Document 2 also shows a method of energizing the heater with the start of the defrosting operation. However, the amount of frost formation is large, and the large frost that has grown in the cooler is slipping off from the cooler. If the frost slippage from the cooler to the tray is prevented during defrosting operation due to (sticking to) the object, the detected temperature of the first thermistor and the second thermistor is higher than the set temperature. However, there is a possibility that the defrosting operation is completed in a state where the frost remains in the vicinity of the cooler without melting. Also, in order to prevent such a defrosting operation from occurring quickly, if the set temperature of the first thermistor and the second thermistor is increased, the operation time becomes longer than necessary and the power consumption during defrosting is increased. End up.

  That is, reducing the power consumption during defrosting in the defrosting operation and ensuring the defrosting reliability are in a trade-off relationship, and even using the techniques disclosed in Patent Literature 1 and Patent Literature 2. The effect obtained is not maximized.

  The present invention has been made in order to solve the above-described problems, and a refrigerator capable of reducing power consumption during defrosting and power consumption during pull-down while ensuring defrosting reliability. The purpose is to obtain.

  The refrigerator according to the present invention includes a cooler that generates cold air by a refrigeration cycle having a compressor, a tray that is disposed below the cooler and receives frost and water that slides down from the cooler, and the cooler directly. A first defrosting means for heating, a second defrosting means for directly heating the tray, a first thermistor disposed in the cooler and detecting the temperature of the cooler, and disposed in the tray A second thermistor for detecting the temperature of the tray; a frosting amount calculating means for calculating the amount of frost adhering to the cooler; and a sliding judgment for judging that frost has slipped from the cooler to the tray. And a control means for controlling the defrosting operation by the first defrosting means and the second defrosting means, wherein the control means calculates the frost formation amount calculated by the frost formation amount calculation means. From the above, the amount of frost sliding onto the tray When it is estimated whether the amount of frost sliding onto the tray is less than a predetermined amount, the first thermistor is used as the end defrosting determination location, and the first thermistor When the defrosting operation is terminated when the detected temperature of the battery becomes equal to or higher than the first set temperature and the amount of frost sliding onto the tray is estimated to be greater than a predetermined amount, the second thermistor is defrosted. The defrosting operation is terminated when the detected temperature of the second thermistor becomes equal to or higher than the second set temperature after the slippage determining means determines that frost has slipped on the tray. Is.

  In the present invention, when the amount of frost on the cooler is small and the amount of frost sliding onto the tray is below a predetermined amount (when the amount of frost sliding down on the tray is small or when there is no frost sliding down on the tray), The defrosting end can be determined only by the first thermistor, and the defrosting can be completed early. Further, in the present invention, when the amount of frost sliding onto the tray is larger than a predetermined amount, the defrosting operation is terminated when the temperature of the tray rises to the set temperature after the sliding determination means determines that the frost has slipped onto the tray. To do. For this reason, even when the sliding of frost onto the tray is hindered, the defrosting reliability can be ensured without the defrosting operation being quickly cut off, and the operation time becomes longer than necessary and the defrosting is performed. It is also possible to prevent an increase in hourly power consumption. As described above, the power consumption during defrosting and the power consumption during pull-down can be reduced while ensuring the defrosting reliability.

It is side surface sectional drawing of the refrigerator which concerns on embodiment of this invention. It is a refrigerant circuit figure of the refrigerator which concerns on embodiment of this invention. It is explanatory drawing (front sectional drawing) which shows the air path structure of the refrigerator which concerns on embodiment of this invention. It is explanatory drawing which shows the cooling chamber 7 of the refrigerator which concerns on embodiment of this invention. It is a top view of the liquid receiving part 8 of the refrigerator which concerns on embodiment of this invention. It is a block diagram which shows the apparatus structure of the control system of the refrigerator which concerns on embodiment of this invention. It is a figure which shows the temperature change of the cooler 25 and the tray 29 at the time of the defrost operation in case the amount of frost formation to the cooler 25 of the refrigerator which concerns on embodiment of this invention is small. It is a figure which shows the temperature change of the cooler 25 and the tray 29 at the time of the defrost operation in case the amount of frost formation to the cooler 25 of the refrigerator which concerns on embodiment of this invention is large. It is a flowchart of the defrost operation control of the refrigerator which concerns on embodiment of this invention. It is a defrost cycle for demonstrating an example of the frost formation amount calculation means of the refrigerator which concerns on embodiment of this invention. It is a figure which shows the relationship between the amount of frost formation to the cooler 25 with respect to the compressor input of the refrigerator which concerns on embodiment of this invention, and external air.

Embodiment.
FIG. 1 is a side sectional view of a refrigerator according to an embodiment of the present invention. FIG. 1 shows the refrigerator according to the present embodiment with the front side (front side) of the refrigerator being the left side of the page. Moreover, in this Embodiment, as shown in FIG. 1, as a refrigerator, as shown in FIG. An example will be described in which an ice making chamber 2 to be stored, and a switching chamber 3 that can be switched to a temperature zone of the freezing chamber 4 or the refrigeration chamber 1 are partitioned and provided. Here, in the following description, unless otherwise specified, the refrigerator compartment 1, the ice making compartment 2, the switching compartment 3, the freezer compartment 4, and the vegetable compartment 5 are collectively referred to as a storage compartment.

  As shown in FIG. 1, the refrigerator of the present embodiment has a cooling chamber 7 formed on the back side. The cooling chamber 7 has a cooler 25, an internal fan 6, and a liquid receiving unit 8. In the normal operation of the refrigerator, the cooler 25 cools the air supplied to the storage chamber by exchanging heat with the refrigerant passing through the inside. The internal fan 6 is a blower that forms an air flow (a flow for circulating the air in the storage chamber) that allows air from the storage chamber to pass through the cooler 25 and sends the cooled air to the storage chamber again. This internal fan 6 is disposed above the cooler 25. The liquid receiver 8 has equipment for receiving frost melting water (drain water) sliding down from the cooler 25, frost sliding down, etc. during the defrosting operation.

  FIG. 2 is a refrigerant circuit diagram of the refrigerator according to the embodiment of the present invention. As shown in FIG. 2, the refrigerator according to the present embodiment connects, for example, a compressor 21, a flow path switching valve 22, a condenser 23, a capillary tube 24, a cooler 25, a header 26, a bypass pipe 27, and a tray pipe 28. Thus, a refrigerant circuit is configured.

  The compressor 21 compresses the gas-phase refrigerant sucked from the suction side to high pressure and high temperature, and sends it out from the discharge side. The compressor 21 has a discharge side connected to the flow path switching valve 22 via a refrigerant pipe, and a suction side connected to the header 26 via the refrigerant pipe.

  The flow path switching valve 22 serving as switching means switches the flow of the refrigerant sent out from the compressor 21. The flow path switching valve 22 has a refrigerant inlet A1, an outlet A2, and an outlet A3, and connects the inlet A1 and the outlet A2 or connects the inlet A1 and the outlet A3. Can be selected by switching. Here, inflow port A1 is connected with the discharge side of compressor 21 via refrigerant piping. The outlet A2 is connected to the condenser 23 via a refrigerant pipe. The outlet A3 is connected to the bypass pipe 27. And when the connection which forms a flow path between inflow port A1 and outflow port A2 is made, the air of a refrigerator is cooled by cooling the cooler 25. FIG. Hereinafter, the connection that forms the flow path between the inlet A1 and the outlet A2 is referred to as “normal connection”, and the operation of cooling by the cooler 25 by the normal connection is referred to as “normal operation”. Moreover, when the connection which forms a flow path between inflow port A1 and outflow port A3 is carried out, the cooler 25 is heated with the refrigerant | coolant from the compressor 21 of the cooler 25. FIG. That is, the bypass pipe 27 corresponds to the first defrosting means of the present invention. Hereinafter, the connection that forms the flow path between the inflow port A1 and the outflow port A3 is referred to as “defrost connection”, and the operation in the defrost connection state is referred to as “defrost operation”.

  The condenser 23 condenses the high-temperature and high-pressure gas-phase refrigerant from the compressor 21 by, for example, heat exchange with air outside the refrigerator when the flow path switching valve 22 is normally connected. The condenser 23 has a refrigerant inlet side connected to the flow path switching valve 22 via a refrigerant pipe, and a refrigerant outlet side connected to the capillary tube 24 via the refrigerant pipe.

  The capillary tube 24 serving as a decompression means (a throttling device) decompresses the liquid-phase or gas-liquid two-phase refrigerant flowing from the condenser 23 into a low-temperature and low-pressure gas-liquid two-phase state. The capillary 24 has a refrigerant inlet side connected to the condenser 23 via a refrigerant pipe, and a refrigerant outlet side connected to the cooler 25 via a tray pipe 28. The refrigerant outlet side of the capillary tube 24 is also connected to the bypass pipe 27.

  For example, the tray pipe 28 is disposed on the lower surface of a tray 29 described later, and is fixed in contact with the tray 29 with a metal tape (not shown) having high thermal conductivity. Thereby, the tray 29 can be effectively heated during the defrosting operation, and the frost sliding down on the tray 29 can be melted. That is, the tray pipe 28 corresponds to the second defrosting means of the present invention. In the present embodiment, for example, a part of the pipe connecting the capillary tube 24 and the cooler 25 is configured. The refrigerant inlet side is connected to the capillary tube 24 and the bypass pipe 27, and the refrigerant outlet side is connected to the cooler 25. When the flow path switching valve 22 is normally connected and performing normal operation, the gas-liquid two-phase refrigerant that has passed through the capillary 24 passes. At this time, it functions as a subcooler and evaporates part of the liquid phase refrigerant. Further, when the flow path switching valve 22 is defrosted and performing a defrosting operation, it functions as a sub radiator, and a high-temperature and high-pressure gas phase that has passed through the flow path switching valve 22 and the bypass pipe 27 from the compressor 21. A refrigerant (which may be a gas-liquid two-phase refrigerant) is radiated. As a result, the frost sliding down on the tray 29 is melted.

  For example, even if a part of the bypass pipe 27 is configured as the tray pipe 28 and the refrigerant outlet of the bypass pipe 27 is connected to the cooler 25, the tray 29 is heated in the defrosting operation to melt the frost. Can be made. Further, a part of the pipe connecting the cooler 25 and the compressor 21 is configured as a tray pipe 28 so that the refrigerant inlet side is connected to the cooler 25 and the refrigerant outlet side is connected to the compressor 21. In the defrosting operation, the tray 29 can be heated to melt the frost. Furthermore, the tray pipe 28 may not be disposed, and a heating means such as a pipe heater may be provided in the tray 29 as the second defrosting means, and the tray 29 may be directly heated by the heating means. At this time, the refrigerant outlet side of the bypass pipe 27 is connected to the cooler 25. Further, the bypass pipe 27 may not be disposed, and a heating unit such as a pipe heater may be provided in the cooler 25 as the first defrosting unit, and the cooler 25 may be directly heated by the heating unit.

  As described above, when the flow path switching valve 22 is normally connected and performing the normal operation, the cooler 25 is supplied with the low-temperature and low-pressure refrigerant in the gas-liquid two-phase state fed through the tray pipe 28 and the cooling chamber 7. Heat exchange with the air inside (the air supplied to the storage chamber), that is, the air inside the cooling chamber 7 (the air supplied to the storage chamber) is cooled, and the low-temperature low-pressure refrigerant in the gas-liquid two-phase state is evaporated and vaporized. To do. In other words, the cooler 25 generates cool air to be supplied to the storage chamber by the refrigeration cycle. The cooler 25 functions as a radiator when the flow path switching valve 22 is defrosted and performing a defrosting operation, and is a high-temperature and high-pressure gas-phase refrigerant (gas-liquid two-phase refrigerant) that has passed through the tray pipe 28. Heat radiation). Thereby, the cooler 25 is heated from the inside, and the frost adhering to the cooler 25 is melted.

  The header 26 is for separating the liquid-phase refrigerant from the refrigerant flowing from the cooler 25 through the refrigerant pipe, and causing the compressor 21 to suck the gas-phase refrigerant. The header 26 has a refrigerant inlet side connected to the cooler 25 via a refrigerant pipe, and a refrigerant outlet side connected to the suction side of the compressor 21 via the refrigerant pipe.

  The bypass pipe 27 is configured such that when the flow path switching valve 22 is defrosted, the high-temperature and high-pressure gas-phase refrigerant (which may be a gas-liquid two-phase refrigerant) discharged from the compressor 21 is supplied to the condenser 23 and the capillary tube 24. Is bypassed and passed through the tray pipe 28 and the cooler 25. The bypass pipe 27 has a refrigerant inlet side connected to the flow path switching valve 22 and a refrigerant outlet side connected to the tray pipe 28.

  FIG. 3 is an explanatory view (front sectional view) showing the air passage structure of the refrigerator according to the embodiment of the present invention. Here, a refrigerator in which the refrigerator compartment 1, the ice making compartment 2, the switching compartment 3, and the freezer compartment 4 are connected by an air passage from the cooling compartment 7 and the vegetable compartment 5 is connected to the refrigerator compartment 1 by an air passage is taken as an example. Use.

  The air cooled by the cooler 25 is sent into the refrigerator compartment 1 from the outlet 41 of the refrigerator compartment 1 via the air passage A connecting the cooling compartment 7 and the refrigerator compartment 1 by the internal fan 6. Since the air in the refrigerator compartment 1 exchanges heat with food in the refrigerator compartment 1, air that flows in from the outside of the refrigerator when the door of the refrigerator compartment 1 is opened and closed, the temperature rises. In addition, the amount of moisture in the refrigerator compartment 1 increases due to the inflow of air having a high absolute humidity.

  Next, the air in the refrigerator compartment 1 flows into the air path B connecting the refrigerator compartment 1 and the vegetable compartment 5 from the return port 46 of the refrigerator compartment 1. Some percent of the air flowing into the air passage B returns directly to the cooling chamber 7 from the return port 46 without passing through the vegetable chamber 5. The rest flows into the vegetable compartment 5 from the outlet 44 of the vegetable compartment 5. The air that has flowed into the vegetable compartment 5 rises in temperature and amount of water, as does the air in the refrigerator compartment 1. Then, the return port 46 returns to the cooling chamber 7.

  Then, the cold air that has become hotter and humider than when it is sent out from the cooling chamber 7 is heat-exchanged in the cooler 25, becomes cold air of low temperature and low humidity again, and is then sent out to the refrigerating chamber 1. For this reason, frost due to dehumidified moisture is preferentially attached to the vicinity of the cooler 25 that is located upstream of the flow of air passing through the cooler 25 and closer to the return port 46.

  The air cooled by the cooler 25 is sent into the freezer compartment 4 from the outlet 43 of the freezer compartment 4 by the internal fan 6. Since the air in the freezer compartment 4 exchanges heat with food in the freezer compartment 4, air that flows in from the outside of the refrigerator by opening and closing the door of the freezer compartment 4, the temperature rises. In addition, the amount of water in the freezer compartment 4 increases due to the flow of air with high absolute humidity. However, since the internal volume of the freezer compartment 4 is smaller than the internal volume of the refrigerator compartment 1, the amount of water contained in the air in the freezer compartment 4 is less than that of the refrigerator compartment 1. Next, the air in the freezer compartment 4 returns from the return port 45 to the cooling chamber 7.

  Note that the air cooled by the cooler 25 is also supplied to the ice making chamber 2 and the switching chamber 3 from the outlet 47 and the outlet 42, respectively. The air cooled in the ice making chamber 2 and the switching chamber 3 also returns to the cooling chamber 7 from a return port (not shown).

  FIG. 4 is an explanatory diagram showing the cooling chamber 7 of the refrigerator according to the embodiment of the present invention. FIG. 5 is a plan view of liquid receiver 8 of the refrigerator according to the embodiment of the present invention. 4A is a view of the cooling chamber 7 viewed from the back side of the refrigerator, and FIG. 4B is a cross-sectional view taken along line AA of FIG. 4A.

  As shown in FIGS. 4 and 5, the liquid receiving unit 8 includes a tray 29 and the tray pipe 28 described above. As shown in FIG. 4, in the present embodiment, the tray pipe 28 is disposed on the lower surface of the tray 29. However, the tray pipe 28 may be disposed on the upper surface side of the tray 29, for example, as long as it can transfer heat to the tray 29 during the defrosting operation.

  The tray 29 receives molten water and frost that slide down from the cooler 25. Here, by configuring the tray 29 with a metal material having a high thermal conductivity, the frost that has slipped down can be melted effectively by heating it during the defrosting operation. When the tray pipe 28 is provided on the upper surface side of the tray 29, the material of the tray 29 may be made of a material having a low thermal conductivity and good heat insulation, such as a polymer material. Furthermore, the material of the tray 29 may be made of, for example, a metal material having a high conductivity, and a heat insulating material having a lower heat conductivity than the tray 29 and a good heat insulating property may be provided on the lower surface of the tray 29. Thereby, it becomes difficult for the heat | fever of a refrigerant | coolant to conduct to parts other than frost, for example, the cooling chamber 7, etc. at the time of a defrost operation, and useless heat dissipation can be suppressed.

  A drain hole 30 is provided in the center of the tray 29. Melted water of frost that has slipped down to the liquid receiver 8 or melted water of frost that has melted in the liquid receiver 8 flows through the drain pipe 9 that leads to the drain hole 30 and is drained to the evaporating dish 10. Here, by making the drain hole 30 have a mesh structure, it is possible to prevent unmelted frost from flowing into the drain pipe 9 and freezing in the middle of the drain pipe 9.

  The water (drain water) stored in the evaporating dish 10 is vaporized by, for example, heat generated by operating the compressor 21, air sent by a fan arranged in the machine room, and the like, and is discharged outside the refrigerator. The

  Here, the frost that has slipped into the drain hole 30 has a small contact area with the tray 29, and therefore, the amount of heat transferred from the tray pipe 28 by heat conduction is insufficient, and is difficult to melt. Therefore, as shown in FIG. 5, a part (I) of the tray pipe 28 is arranged in the vicinity of the drain hole 30, and the amount of heat supplied to the vicinity of the drain hole 30 is increased, so that the drain hole 30 is caused by the frost that has fallen. Blocking can be prevented. For example, when the tray pipe 28 is provided on the upper surface of the tray 29, a part (I) of the tray pipe 28 may pass through the drain hole 30.

  As shown in FIG. 4, the cooler 25 is provided with a first thermistor 61 that detects the temperature of the cooler 25. Based on the temperature of the cooler 25 detected by the first thermistor 61, the control means 70 described later determines the end of the defrosting operation. The first thermistor 61 is desirably arranged in the cooler 25 on the upstream side of the air flowing from the storage chamber into the cooling chamber 7 and in the vicinity of the return port of the air passage. The first thermistor 61 is desirably arranged in the vicinity of the return port through which air that has flowed out of the storage chamber having the highest humidity passes. That is, the first thermistor 61 desirably detects the temperature at a position where the amount of frost formation is large on the surface of the cooler 25. If the first thermistor 61 determines that the frost at this position has melted completely by detecting the temperature at the position where the frost formation is considered to be the slowest, the frost is melted completely. It can be determined that the attached frost is completely melted, and even if only one first thermistor 61 is attached, the reliability of defrosting is improved.

Further, as shown in FIGS. 4 and 5, the tray 29 is provided with a second thermistor 62 that detects the temperature of the tray 29. Based on the temperature of the tray 29 detected by the second thermistor 62, the control means 70 described later determines the end of the defrosting operation. Here, the second thermistor 62 is preferably attached at a position almost directly below the first thermistor 61 where the amount of frost sliding down the cooler 25 is large. When the second thermistor 62 detects the temperature at the position where the frost is most likely to fall on the tray 29, it is determined that the frost at this position has completely melted. It will be determined that it has melted, leading to improved reliability of defrosting.
Note that the arrangement position of the second thermistor 62 does not have to be strictly below the first thermistor 61, and can be any position in the tray 29 that can detect the temperature in the vicinity of the position immediately below the first thermistor 61. Good.

  Next, the detailed arrangement position of the first thermistor 61 will be described. As described above, the air that has returned to the cooling chamber 7 from the return port 46 is the air that has passed through the refrigerator compartment 1 (more specifically, the air that has returned directly from the refrigerator compartment 1 or the vegetable compartment 5 from the refrigerator compartment 1). Air that came back through). For this reason, in the cooler 25, frost adheres preferentially to the position where the air returned from the return port 46 to the cooling chamber 7 flows. For this reason, in the present embodiment, the first thermistor 61 is disposed at a position corresponding to the return port 46 on the upstream side of the air in the cooler 25. Specifically, since the return port 46 is disposed below the cooler 25 in the refrigerator according to the present embodiment, the first thermistor 61 is disposed below the cooler.

(Defrosting operation)
Next, a defrosting operation operation of the refrigerator configured as in the present embodiment will be described.

  FIG. 6 is a block diagram showing a device configuration of a control system of the refrigerator according to the embodiment of the present invention. The control means 70 shown in FIG. 6 controls the apparatus etc. in a refrigerator. In the present embodiment, the control unit 70 estimates whether or not the amount of frost sliding onto the tray 29 is equal to or less than a predetermined amount based on the frost amount detected by the frost amount calculation unit 63. And the control means 70 is the 1st thermistor, when the amount of frost sliding on the tray 29 is below a predetermined amount (when the amount of frost sliding down on the tray 29 is small, or when there is no frost sliding down on the tray 29). 61 is selected as the defrosting end determination position, and it is determined whether or not to end the defrosting operation based on the temperature detected by the first thermistor 61. Further, the control means 70 selects the first thermistor 62 as the defrosting end determination position when the amount of frost sliding onto the tray 29 is larger than the predetermined amount, and the sliding determination means 64 causes the frost to slide onto the tray 29. After the determination, it is determined whether or not to end the defrosting operation based on the temperature detected by the second thermistor 62. Moreover, the control means 70 performs the control regarding the setting regarding the motor rotation speed of the compressor 21 in the refrigerant circuit, rotation and stop of the internal fan 6, and connection switching of the flow path switching valve 22 at the start and end of the defrosting operation. Do.

  The refrigerator according to the present embodiment performs a normal operation for cooling food in the storage room continuously for a predetermined time. After performing the normal operation for a predetermined time (for example, about one day), the control means 70 performs the defrost operation by switching the flow path switching valve 22 to the defrost connection. At this time, the defrosting operation with a small amount of frost on the cooler 25 is performed under conditions where the absolute humidity outside the refrigerator is low, the door opening / closing frequency is low, or the door opening / closing time is short as in winter. . That is, the defrosting operation is performed under the condition that the amount of frost sliding onto the tray 29 is a predetermined amount or less (the condition where the amount of frost sliding down on the tray 29 is small, or the condition where there is no frost sliding down on the tray 29). On the other hand, defrosting operation with a large amount of frost on the cooler 25 under conditions where the absolute humidity outside the cabinet is high, the number of door opening / closing times is large, or the door opening / closing time is long as in summer. It becomes. That is, the defrosting operation is performed under the condition that the amount of frost sliding onto the tray 29 is greater than a predetermined amount.

  FIG. 7 is a diagram showing temperature changes of the cooler 25 and the tray 29 during the defrosting operation when the amount of frost on the cooler 25 of the refrigerator according to the embodiment of the present invention is small. The vertical axis in FIG. 7 shows the temperature of the cooler 25 detected by the first thermistor 61 and the temperature of the tray 29 detected by the second thermistor 62, and the horizontal axis shows the elapsed time from the start of defrosting. Show.

  As shown in FIG. 7, when the defrosting operation is started, the temperature of the tray 29 receives heat from the high-temperature refrigerant in the tray pipe 28 and rises to 0 ° C. (B1). On the other hand, the cooler 25 also receives heat from the high-temperature refrigerant flowing in the cooler 25 and rises to 0 ° C. (A1). Here, for example, when the contact area between the tray 29 and the tray pipe 28 is small, the temperature of the tray 29 becomes 0 ° C. later than the cooler 25. On the other hand, depending on the specifications of the cooler 25 and the tray 29, the tray 29 may reach 0 ° C. earlier than the cooler 25, but both of them can achieve the same effect in the present invention.

  When the temperature of the tray 29 reaches 0 ° C., the tray 29 functions as a sub radiator, so that the heat of the refrigerant in the tray pipe 28 is used for melting of frost attached to the tray 29 (phase change from solid to liquid). Will be. For this reason, the temperature of the tray 29 becomes 0 ° C. until the frost on the tray 29 is completely melted (B2). When the frost on the tray 29 is completely melted, the temperature of the tray 29 rises (B3). Here, when the amount of frost formation is small, the constant time of 0 ° C. is shortened, and when frost formation is not performed, B2 is absorbed by B1.

  Between B1 and B3, the frost attached to the cooler 25 is also melted (A2). And if the frost of the cooler 25 melt | dissolves completely, the temperature of the cooler 25 will rise (A3). Here, as with the tray 29, when the amount of frost formation is small, the constant time of 0 ° C. is shortened, and when frost formation is not performed, A2 is absorbed by A1.

  During the defrosting operation when the amount of frost on the cooler 25 is small, even if only the frost melting water slides or the frost slips from the cooler 25 to the tray 29, the amount is small. That is, even if the frost from the cooler 25 to the tray 29 slips, the temperature of the tray 29 does not decrease so much (it does not decrease to around 0 ° C.). Further, even if the frost from the cooler 25 to the tray 29 slips, the time for the frost to melt on the tray 29 is very short. Therefore, during the defrosting operation when the amount of frost on the cooler 25 is small, the control means 70 ends the defrosting operation when the temperature of the cooler 25 becomes equal to or higher than the set temperature (first set temperature). To do. In other words, the control means 70 ends the defrosting operation when the detected temperature of the first thermistor 61 becomes equal to or higher than the set temperature (first set temperature).

  FIG. 8 is a diagram illustrating temperature changes of the cooler 25 and the tray 29 during the defrosting operation when the amount of frost on the cooler 25 of the refrigerator according to the embodiment of the present invention is large. The vertical axis in FIG. 8 shows the temperature of the cooler 25 detected by the first thermistor 61 and the temperature of the tray 29 detected by the second thermistor 62, and the horizontal axis shows the elapsed time from the start of defrosting. Show.

  As shown in FIG. 8, when the defrosting operation is started, the temperature of the tray 29 receives heat from the high-temperature refrigerant in the tray pipe 28 and rises to 0 ° C. (B1). On the other hand, the cooler 25 also receives heat from the high-temperature refrigerant flowing in the cooler 25 and rises to 0 ° C. (A1).

  When the temperature of the tray 29 reaches 0 ° C., the heat of the refrigerant is used to melt the frost of the tray 29 (phase change from solid to liquid). For this reason, the temperature of the tray 29 becomes 0 ° C. until the frost on the tray 29 is completely melted (B2). When the frost on the tray 29 is completely melted, the temperature of the tray 29 rises (B3).

  Between B1 and B3, the frost attached to the cooler 25 is also melted (A2). When the frost of the cooler 25 is melted to some extent, the frost generally slides from the cooler 25 to the tray 29. However, when the amount of frost formation on the cooler 25 is large, large frost that has grown in the cooler 25 may adhere to (be caught by) objects other than the cooler while sliding from the cooler 25. Since hot gas defrosting is an internal fusion type, it is difficult to transfer heat to the frost adhered to other than the cooler 25. Moreover, since the cooler 25 vicinity is low temperature, the adhering frost may freeze. Therefore, as shown in FIG. 8, frost may not slide down even if the cooler is 0 ° C. or higher, and the frost slides down after a certain amount of time has elapsed since the cooler became 0 ° C. or higher. When the frost in the cooler 25 slides down, the temperature of the tray 29 that has risen rapidly decreases to around 0 ° C. (B4). Then, the heat of the refrigerant flowing in the tray pipe 28 is used again for melting the frost that has fallen on the tray 29 (phase change from solid to liquid) until the frost on the tray 29 is completely melted. The temperature of the tray 29 is constant at 0 ° C. (B5).

Since the frost does not exist in the cooler 25 between B4 and B5, the temperature of the cooler 25 rises (A3). On the other hand, when the frost sliding down on the tray 29 is completely melted, the temperature of the tray 29 rises again (B6). Therefore, during the defrosting operation when the amount of frost on the cooler 25 is large, the control means 70 determines that the frost has fallen on the tray 29 after the sliding-off determination means 64 has reached the set temperature ( When the temperature is equal to or higher than the second set temperature, the defrosting operation is terminated. In other words, the control means 70 defrosts when the detected temperature of the second thermistor 62 becomes equal to or higher than the set temperature (second set temperature) after the slippage determining means 64 determines that the frost has slipped onto the tray 29. The operation is terminated (B6).
Note that the set temperature of the first thermistor 61 (first set temperature) and the set temperature of the second thermistor 62 (second set temperature) may be the same value or different values. Good.

  FIG. 9 is a flowchart of the defrosting operation control of the refrigerator according to the embodiment of the present invention. Based on FIG. 9, the control at the time of the defrost operation which the control means 70 performs is demonstrated.

  When the normal operation is performed for a predetermined time (for example, about one day), the control means 70 starts the defrosting operation (S101).

  When the defrosting operation is started, the control means 70 stops the operation of the internal fan 6 (S102). And the control means 70 switches the flow-path switching valve 22 to a defrost connection (S103). As a result, the high-temperature and high-pressure refrigerant discharged from the compressor 21 is supplied to the tray pipe 28 and the cooler 25 via the bypass pipe 27. Here, the control means 70 fixes the (motor) rotation speed of the compressor 21 (S104). At this time, by setting the rotation speed to a high speed so that the discharge pressure of the compressor 21 does not exceed the specified pressure, more heat can be supplied, the defrosting time can be shortened, and the defrosting operation can be performed. Power consumption can be reduced. Further, the compressor 21 is provided with a heat dissipating fan for the compressor 21, and detects the outside temperature (outside air temperature) and the temperature of the compressor 21 (more specifically, the surface temperature of the shell of the compressor 21). When there is a means, the heat dissipating fan is stopped when the temperature of the compressor 21 becomes equal to or higher than the outside temperature during the defrosting operation, and is driven when the temperature of the compressor 21 becomes equal to or lower than the outside temperature. Thus, more heat can be supplied to the frost.

  Thereafter, the control means 70 calculates the frost amount by the frost amount calculation means 63 (S105). Further, the control means 70 estimates whether or not the amount of frost sliding down from the cooler 25 to the tray 29 is equal to or less than a predetermined amount based on the calculated amount of frost formation (S106).

  When the amount of frost sliding down from the cooler 25 to the tray 29 is estimated to be equal to or less than a predetermined amount (S106; YES), the control means 70 detects the temperature detected by the first thermistor 62 as the temperature of the cooler 25. (S107). Then, the control means 70 records the detected temperature of the cooler 25.

  Next, the control means 70 determines whether or not the temperature of the cooler 25 is higher than the set temperature (first set temperature) (S108). If it is determined that the temperature of the cooler 25 is equal to or lower than the set temperature (first set temperature) (S108; NO), the control means 70 returns to S107 and again determines based on the temperature of the cooler 25, etc. I do.

  On the other hand, if it determines with the temperature of the cooler 25 being higher than preset temperature (1st preset temperature) (S108; YES), the control means 70 will set the flow-path switching valve 22 to normal connection as what defrosting complete | finished. Switching (S113). And the control means 70 cancels | releases fixation of compressor rotation speed (S114), drives the internal fan 6 (S115), and complete | finishes a defrost operation (S116).

  When it is estimated that the amount of frost sliding down from the cooler 25 to the tray 29 is larger than the predetermined amount (S106; NO), the control means 70 determines whether or not the frost has slipped down to the tray 29 by the sliding-down determination means 64. Based on the determination (S109), the process proceeds to the next step. That is, if it is determined that frost has not slipped onto the tray 29 (S110; NO), the control means 70 returns to S109. If it is determined that frost has slipped onto the tray 29 (S110; YES), the control means 70 detects the temperature detected by the second thermistor 62 as the temperature of the cooler 25 (S111). Then, the control means 70 records the detected temperature of the cooler 25.

  Next, the control means 70 determines whether or not the temperature of the tray 29 is higher than the set temperature (second set temperature) (S112). When it is determined that the temperature of the cooler 25 is equal to or lower than the set temperature (second set temperature) (S112; NO), the control unit 70 returns to S111 and performs determination based on the temperature of the tray 29 again. .

  If it determines with the tray 29 being higher than preset temperature (2nd preset temperature) (S112; YES), the control means 70 will switch the flow-path switching valve 22 to normal connection as what defrosting complete | finished (S113). And the control means 70 cancels | releases fixation of compressor rotation speed (S114), drives the internal fan 6 (S115), and complete | finishes a defrost operation (S116).

  Here, for example, the frost formation amount calculation means 63 forms frost on the cooler 25 based on the difference between the absolute humidity inside the refrigerator and the absolute humidity outside the refrigerator, and the number of times the door of the storage room is opened and closed. A means for calculating the quantity is used. Under conditions where the absolute humidity outside the refrigerator is high, such as in summer, the difference between the absolute humidity inside the refrigerator and the absolute humidity outside the refrigerator becomes large, and the amount of moisture that enters the cabinet from the outside when the door is opened and closed once. Will increase. Moreover, if the frequency | count of opening and closing a door increases by the start of defrosting, the total amount of the water | moisture content which penetrate | invades in a warehouse will become large. That is, the difference between the absolute humidity inside the refrigerator and the absolute humidity outside the refrigerator and the number of times the door of the storage room is opened and closed are correlated with the amount of frost on the cooler 25. For this reason, the amount of frost formation to the cooler 25 is calculated by arranging means for detecting the difference between the absolute humidity inside the refrigerator and the absolute humidity outside the refrigerator and the number of times the door of the storage room is opened and closed. It becomes possible.

  Further, for example, the frost formation amount calculation means 63 is a means for calculating the frost formation amount to the cooler 25 based on the outside air temperature (the temperature outside the refrigerator) and the operation time of the compressor 21. When there is much frost adhering to the cooler 25, the thermal resistance between the refrigerant | coolant which flows the inside of the cooler 25, and the air in a store | warehouse | chamber increases, and the amount of heat exchange falls. Therefore, it takes time to cool the inside of the refrigerator to the set temperature, and the operation time of the compressor 21 increases. Therefore, there is a correlation between the amount of frost formation on the cooler 25 and the compressor operation time. On the other hand, when the outside air temperature rises in a general refrigerator, the amount of heat intrusion from the outside of the compartment into the inside increases, so that the operation time of the compressor 21 increases. Therefore, there is a correlation between the outside air temperature and the compressor operation time. That is, in addition to the operation time detection means of the compressor 21, if the outside temperature detection means for distinguishing the change in the compressor operation time due to the frost formation amount and the outside air temperature is arranged, the frost formation amount to the cooler 25 can be reduced. It is possible to calculate.

  Further, for example, the frost formation amount calculation means 63 is a means for calculating the frost formation amount to the cooler 25 based on the difference between the refrigerator internal temperature and the cooler 25 temperature. When there is much frost adhering to the cooler 25, the thermal resistance between the refrigerant | coolant which flows the inside of the cooler 25, and the air in a store | warehouse | chamber increases, and the amount of heat exchange falls. Therefore, the temperature difference between the refrigerator internal temperature and the refrigerant flowing in the cooler 25 increases. Therefore, there is a correlation between the temperature difference between the refrigerant flowing in the cooler 25 and the internal air, and the temperature of the refrigerant flowing in the cooler 25 and the temperature detection means for the internal air are arranged, whereby the cooler 25 It becomes possible to calculate the amount of frost formation on. The temperature of the refrigerant flowing in the cooler 25 may be detected by, for example, a thermistor (for example, the first thermistor 61) disposed on the surface of the cooler 25 as a representative temperature.

  Further, for example, the frost formation amount calculation means 63 is supplied to the cooler 25 based on the input (input power) of the compressor 21, the shell surface temperature of the compressor 21, the outside air temperature, and the temperature of the cooler 25. It is a means for calculating the amount of frost formation. A specific principle is demonstrated using the defrost cycle figure of FIG. Hot gas defrosting amplifies the energy of the refrigerant by pressurizing and compressing the refrigerant by the input supplied to the compressor 21, and adheres to the cooler 25 by flowing the high-energy refrigerant to the cooler 25. Heat and melt the frost. Therefore, the specific enthalpy of the refrigerant is low before being sucked into the compressor 21 (Iout), but when the refrigerant is sucked into the compressor 21 and compressed in the compression mechanism of the compressor 21, the specific enthalpy of the refrigerant increases. (Iin '). At this time, the energy by which the refrigerant is compressed and amplified by the compressor 21 is equal to the input of the compressor 21.

  The compressed refrigerant dissipates heat until it is discharged out of the shell of the compressor 21, and the specific enthalpy decreases (Iout '). In general, the compressor 21 of the refrigerator is a low-pressure shell, and a discharge pipe is arranged in the shell of the compressor 21 so as to enclose a low-pressure refrigerant before being sucked into the compression mechanism. The refrigerant discharged from the compression mechanism of the compressor 21 passes through this discharge pipe and is then discharged outside the shell of the compressor 21. Therefore, the refrigerant discharged from the compression mechanism of the compressor 21 radiates heat to the low-pressure refrigerant in the shell when passing through the discharge pipe of the compressor 21. The low-pressure refrigerant in the shell that has received heat from the discharge pipe radiates heat to the outside air through the shell. When the compressor 21 is exposed to low outside air, or when a fan for cooling the shell of the compressor 21 is rotating, the heat dissipation amount increases.

  The refrigerant discharged outside the shell of the compressor 21 is depressurized when passing through the bypass pipe 27 (Iin). This refrigerant after passing through the bypass pipe 27 dissipates heat to the frost attached to the cooler 25 and the cooler 25 when passing through the cooler 25, and the specific enthalpy decreases (Iout). Here, energy obtained by multiplying the specific enthalpy by the flow rate of the refrigerant is energy, and the energy balance of the defrost cycle is expressed by the following equation (1).

ここで、Ｗは圧縮機２１の入力、Ｇ_rは冷媒の流量、Ｉ_in’は圧縮機２１のシェル内の吐出配管中に存在する冷媒の比エンタルピー、Ｉ_out’は圧縮機２１のシェル外に吐出された冷媒の比エンタルピー、Ｉ_inは冷却器２５の入口における冷媒の比エンタルピー、Ｉ_outは冷却器２５の出口における冷媒の比エンタルピーである。

Here, W is the input of the compressor 21, G _r is the flow rate of the refrigerant, I _in ′ is the specific enthalpy of the refrigerant existing in the discharge pipe in the shell of the compressor 21, and I _out ′ is outside the shell of the compressor 21. Is the specific enthalpy of the refrigerant discharged at, I _in is the specific enthalpy of the refrigerant at the inlet of the cooler 25, and I _out is the specific enthalpy of the refrigerant at the outlet of the cooler 25.

G _r (I _in '-I _out ') _in the equation (1) indicates the shell heat dissipation of the compressor 21 using the change in the specific enthalpy of the refrigerant, and the shell surface exchanges heat with the surrounding air. As a thing, it can represent like following Formula (2).

ここで、Ａは圧縮機２１のシェルの外表面積、αはシェルの周囲熱伝達率、Ｔ_shは圧縮機２１のシェル表面温度、Ｔ_aは圧縮機２１の周囲の空気温度である。Ａαは圧縮機２１の仕様と周辺の気流の状態により一様に決まる値である。

Here, A is the outer surface area of the shell of the compressor 21, alpha is around heat transfer coefficient of the shell, the T _sh shell surface temperature of the compressor 21, the T _a is the ambient air temperature of the compressor 21. Aα is a value that is uniformly determined by the specifications of the compressor 21 and the state of the surrounding airflow.

On the other hand, G _r (I _in −I _out ) indicates the heat radiation to the cooler 25 and frost attached to the cooler 25 using the change in the specific enthalpy of the refrigerant. It can be expressed as the following equation (3) using the change.

ここで、ｍ_rは冷却器２５の質量、Ｃ_rは冷却器２５の比熱、ｍ_fは冷却器２５への着霜量、Ｃ_fは霜の比熱、Ｔ_nはｎ時間経過時の冷却器２５の温度、Ｔ_n-1はｎ−１時間経過時の冷却器２５の温度である。ｍ_r及びＣ_rは冷却器２５の仕様によって一様に決まる値であり、Ｃ_fは霜の物性によって一様に決まる値である。すなわち、式（１），（２），（３）を変形すると次式（４）となり、圧縮機２１の入力、圧縮機２１のシェル表面温度、外気温度及び冷却器２５の温度を測定すれば、冷却器２５への着霜量を算出可能となる。

Here, m _r is the mass of the cooler 25, C _r is the specific heat of the cooler 25, m _f is frost formation amount of the cooler 25, C _f frost specific heat, T _n is cooler when the elapsed n times 25, T _n-1 is the temperature of the cooler 25 when n-1 hours have elapsed. m _r and C _r is a value determined uniformly by the specification of the cooler 25, C _f is a value determined uniformly by the physical properties of the frost. That is, when the equations (1), (2), (3) are transformed, the following equation (4) is obtained, and if the input of the compressor 21, the shell surface temperature of the compressor 21, the outside air temperature, and the temperature of the cooler 25 are measured. The amount of frost formation on the cooler 25 can be calculated.

FIG. 11 is a diagram showing the relationship between the amount of frost formed on the cooler 25 and the outside air with respect to the compressor input of the refrigerator according to the embodiment of the present invention.
In the case of hot gas defrosting in which there is shell heat dissipation of the compressor 21, the amount of heat radiated to the cooler 25 and the frost depends on the outside air. For example, when the outside air temperature is low even with the same amount of frost formation, the shell heat dissipation of the compressor 21 increases, and the cooling amount of the cooler 25 and the frost decreases. Therefore, when the shell heat dissipation of the compressor 21 is not taken into account, the detection accuracy of the amount of frost formation decreases. On the other hand, by considering the heat dissipation of the shell as in equation (2), it is possible to accurately calculate the frost formation amount regardless of the outside air temperature, and the frost formation amount calculation accuracy can be improved.

  Here, in the present embodiment, taking a low-pressure shell type compressor as an example, cooling is performed based on the input of the compressor 21, the shell surface temperature of the compressor 21, the outside air temperature, and the temperature of the cooler 25. The frost formation amount calculation means 63 for calculating the frost formation amount on the container 25 has been described. However, the frosting amount calculation means 63 is of course also employed in a refrigerator having a compressor other than the low-pressure shell type, such as a high-pressure shell type compressor in which the high-pressure refrigerant compressed by the compression mechanism is enclosed in the shell. be able to. That is, by using the frost amount calculation means 63 in the refrigerator in which the compressor 21 is installed in an environment where the shell surface temperature of the compressor 21 is higher than the outside air temperature, the shell heat dissipation is taken into account as expressed by Equation (2). By doing so, it becomes possible to calculate the frost formation amount accurately regardless of the outside air temperature, and it is possible to improve the frost formation amount calculation accuracy.

In addition, a refrigerator in which the compressor 21 is installed in an environment where the shell surface temperature of the compressor 21 is equal to or lower than the outside air temperature, or a heat insulating member (for example, urethane or vacuum heat insulating material) is provided on the shell surface of the compressor 21. When there is no (or few) shell heat dissipation from the compressor 21 as in a refrigerator, etc., it can be handled by omitting Gr (I _in '-I _out '), and the measurement location is also a cooler The temperature of 25 and the input of the compressor 21 can be used.

  Moreover, in FIG. 11, although the temperature of the cooler 25 is heated until it becomes -10 degreeC from defrost start temperature, this frosting amount calculation means 63 does not prescribe | regulate especially the detection end temperature of the cooler 25. Absent. It is necessary to end the detection at a section where the temperature of the cooler 25 is rising at least after the start of the defrosting operation, and it is preferable that the temperature of the cooler 25 is a section of 0 ° C. or less. Alternatively, if the temperature rise of the cooler 25 is stable, the compressor input change amount per unit time may be used without using the integrated value.

  Here, for example, the sliding-down determination means 64 records the detection temperature of the second thermistor 62 at regular intervals during the defrosting operation, and the detection temperature recorded n-1 times from the detection temperature recorded n times. This is a means for determining that frost has fallen on the tray 29 when the value obtained by subtracting the value becomes equal to or less than the set value. When frost slides down on the tray 29, the temperature detected by the second thermistor 62 decreases. Therefore, it is possible to detect sliding from the amount of decrease in the detection temperature of the second thermistor 62.

  Further, for example, the slippage determining means 64 is a means for determining that the frost has slipped to the tray 29 when the temperature detected by the second thermistor 62 decreases to near 0 ° C. during the defrosting operation. When a 0 ° C. frost having a heat capacity slides on the tray 29 by a predetermined amount or more, the detected temperature of the second thermistor 62 is lowered to a temperature near 0 ° C. At this time, by determining that the frost has slipped onto the tray 29, the second thermistor 62 can detect the frost sliding onto the tray 29. Depending on the specifications of the cooler 25 and the tray 29, frost may slide on the tray 29 before the detected temperature of the second thermistor 62 rises from around 0 ° C. In this case, when the state where the detected temperature of the second thermistor 62 is in the vicinity of 0 ° C. continues for a predetermined time or longer, it is determined that the frost has slipped to the tray 29, so that the second thermistor 62 Can detect sliding down.

  In addition, although the several sliding determination means 64 was demonstrated above, one of these may be employ | adopted for the refrigerator which concerns on this Embodiment, and several of these are refrigerators which concern on this Embodiment. May be adopted. The determination accuracy can be improved by determining the frost sliding on the tray 29 by the plurality of sliding determination means 64.

  As mentioned above, in the refrigerator comprised like this Embodiment, when the amount of frost formation to the cooler 25 is small and the amount of frost sliding down to the tray 29 is below a predetermined amount (the amount of frost sliding down on the tray 29 is When there is little or no frost sliding down on the tray 29), the defrosting end can be determined only by the first thermistor, and the defrosting can be completed early. Further, in the refrigerator configured as in the present embodiment, when the amount of frost sliding onto the tray 29 is greater than a predetermined amount, after the sliding determination means 64 determines that the frost has slipped onto the tray 29, the tray 29 The defrosting operation is terminated when the temperature of the battery rises to the set temperature. For this reason, even when the sliding of frost onto the tray 29 is hindered, the defrosting reliability can be ensured without premature defrosting operation, and the operation time becomes longer than necessary. It is also possible to prevent an increase in frost power consumption. As described above, the power consumption during defrosting and the power consumption during pull-down can be reduced while ensuring the defrosting reliability.

  1 Refrigeration room, 2 ice making room, 3 switching room, 4 freezing room, 5 vegetable room, 6 internal fan, 7 cooling room, 8 liquid receiving part, 9 drain pipe, 10 evaporating dish, 21 compressor, 22 channel switching Valve, 23 Condenser, 24 Capillary, 25 Cooler, 26 Header, 27 Bypass piping, 28 Tray piping, 29 Tray, 30 Drain hole, 41 Outlet, 42 Outlet, 43 Outlet, 44 Outlet, 45 Return port 46, return port, 47 outlet, 61 first thermistor, 62 second thermistor, 63 frost formation amount calculating means, 64 slippage judging means, 70 control means.

Claims (9)

A cooler for generating cold air by a refrigeration cycle having a compressor;
A tray that is disposed below the cooler and receives frost and water sliding down from the cooler;
First defrosting means for directly heating the cooler;
A second defrosting means for directly heating the tray;
A first thermistor disposed in the cooler and detecting a temperature of the cooler;
A second thermistor disposed on the tray for detecting the temperature of the tray;
Frost formation amount calculating means for calculating the amount of frost attached to the cooler;
Sliding judgment means for judging that frost has slipped from the cooler to the tray;
Control means for controlling the defrosting operation by the first defrosting means and the second defrosting means;
With
The control means includes
From the frost amount calculated by the frost amount calculating means, it is estimated whether or not the amount of frost sliding onto the tray is a predetermined amount or less,
When it is estimated that the amount of frost sliding onto the tray is equal to or less than a predetermined amount, the first thermistor is used as the end defrosting determination location, and the detected temperature of the first thermistor is equal to or higher than the first set temperature. The defrosting operation is terminated when
When it is estimated that the amount of frost sliding onto the tray is greater than a predetermined amount, the second thermistor is used as the end defrosting determination location, and the sliding determination means determines that frost has slipped onto the tray. Then, the defrosting operation is terminated when the detected temperature of the second thermistor becomes equal to or higher than the second set temperature. In the state where the shell surface temperature of the compressor is higher than the outside air temperature,
The amount of frost formation calculating means calculates the amount of frost attached to the cooler based on the input of the compressor, the temperature of the cooler, the outside air temperature, and the shell surface temperature of the compressor. The refrigerator according to claim 1. In the state where the shell surface temperature of the compressor is below the outside air temperature,
The refrigerator according to claim 1, wherein the frost amount calculation means calculates the amount of frost attached to the cooler based on an input of the compressor and a temperature of the cooler. The compressor is provided with a heat insulating member on the surface of the shell,
The refrigerator according to claim 1, wherein the frost amount calculation means calculates the amount of frost attached to the cooler based on an input of the compressor and a temperature of the cooler.   The amount of frost formation calculating means calculates the amount of frost attached to the cooler based on the difference between the absolute humidity inside the refrigerator and the absolute humidity outside the refrigerator, and the number of times the door of the storage room is opened and closed. The refrigerator according to claim 1.   The refrigerator according to claim 1, wherein the frost amount calculation unit calculates the amount of frost attached to the cooler based on an outside air temperature and an operation time of the compressor.   2. The refrigerator according to claim 1, wherein the frost amount calculation unit calculates an amount of frost attached to the cooler based on a difference between an internal temperature of the refrigerator and a temperature of the cooler. .   The slippage determining means records the detected temperature of the second thermistor at regular intervals during the defrosting operation, and sets a value obtained by subtracting the detected temperature recorded at the (n-1) th time from the detected temperature recorded at the nth time. The refrigerator according to any one of claims 1 to 7, wherein when it becomes equal to or less than the value, it is determined that frost has slipped from the cooler to the tray. The slippage judging means is
During the defrosting operation, when the detected temperature of the second thermistor is close to 0 ° C. for a predetermined time or more, or the detected temperature of the second thermistor decreases to near 0 ° C. The refrigerator according to any one of claims 1 to 8, wherein it is determined that frost has fallen from the cooler to the tray.

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