Refrigerator

Abstract

To provide a refrigerator capable of efficiently preventing failure relating to cooling of a storage chamber caused by deteriorating defrosting of a cooler.SOLUTION: A refrigerator comprises a storage chamber, a cooler that generates cold air to cool the storage chamber, a plurality of heating units with different defrosting capacities for the cooler, and a control unit capable of individually driving the plurality of heating units to defrost the cooler. The plurality of heating units includes a first heating unit and a second heating unit having a lower defrosting capacity than the first heating unit. The control unit drives the second heating unit and suppresses driving of the first heating unit when a predetermined condition is satisfied under which a cooling function of the cooler is reduced due to frost formation.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] An embodiment of the present invention relates to a refrigerator. [Background technology]

[0002] Conventionally, for a refrigerator that uses a heater to defrost frost on a cooler, a technology is known in which power is supplied to a defrost heater and a gutter heater in response to a frost detection signal to heat the cooler, a drain gutter, and a drain pipe, and power supply to the defrost heater is stopped in response to a defrost completion signal, while power supply to the gutter heater is continued for a predetermined time after power supply to the defrost heater is stopped, thereby reducing power consumption by the heater and achieving economy. In the conventional configuration, the defrost heater is for defrosting the cooler, and the gutter heater is for preventing melted water from the cooler received in the drain gutter from freezing in the drain gutter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-167896 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional configuration, two heaters are used to defrost the cooler and prevent the drainage gutter from freezing, and it is assumed that the defrosting of the cooler is performed only by the defrost heater arranged in contact with or close to the cooler. Therefore, even when alleviating the deterioration of cooling performance due to slight frost on the cooler, that is, frost deterioration, the frost on the cooler is melted by heating with the defrost heater. Therefore, there is a possibility that excessive heat is transmitted into the space around the cooler, which may cause problems with cooling in the storage room. As such, the conventional configuration has a problem that it cannot flexibly respond to the state of frost deterioration of the cooler.

[0005] Therefore, the present embodiment provides a refrigerator that can efficiently prevent problems with cooling of the storage compartment caused by frost deterioration of the cooler. [Means for solving the problem]

[0006] A refrigerator according to an embodiment includes a storage compartment, a cooler that generates cold air to cool the storage compartment, a plurality of heating sections having different defrosting capacities for the cooler, and a control section capable of individually driving the plurality of heating sections to defrost the cooler, the plurality of heating sections including a first heating section and a second heating section having a lower defrosting capacity than the first heating section, and the control section drives the second heating section and suppresses driving of the first heating section when a predetermined condition is met under which the cooling function of the cooler is reduced due to frost. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a front view showing an example of a configuration of a refrigerator according to a first embodiment; [Diagram 2] FIG. 1 is a cross-sectional view showing an example of a configuration of a refrigerator according to a first embodiment. [Diagram 3] FIG. 1 is a block diagram showing an example of an electrical configuration of a refrigerator according to a first embodiment. [Figure 4] FIG. 1 is a perspective view showing an example of an installation position of a defrost heater and a gutter heater in a refrigerator according to a first embodiment; [Diagram 5] FIG. 1 is a cross-sectional view showing an example of an installation position of a defrost heater and a gutter heater in a refrigerator according to a first embodiment. [Figure 6] A time chart showing an example of drive control of a defrost heater and a gutter heater in the refrigerator according to the first embodiment. [Figure 7] A flowchart showing an example of control content when partial defrost control is performed in the refrigerator according to the first embodiment. [Figure 8] A flowchart showing an example of control content when partial defrost control is performed in a refrigerator according to a second embodiment. [Figure 9] A time chart showing an example of drive control of a defrost heater and a gutter heater in a refrigerator according to a third embodiment. [Figure 10] A time chart showing an example of drive control of a trough heater and a refrigeration blower in a refrigerator according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a number of embodiments of the present invention will be described with reference to the drawings. In each embodiment, substantially identical elements are given the same reference numerals, and descriptions thereof will be omitted. In addition, in the following embodiments, the terms "first" and "second" attached to components are merely intended to distinguish between similar components, and do not indicate superiority or inferiority between the components.

[0009] (First embodiment) First, a first embodiment of the present invention will be described with reference to FIGS. As shown in Fig. 1 and Fig. 2, refrigerator 1 is configured to have multiple storage compartments inside refrigerator body 10, which is a vertically long rectangular box with an open front. In the following description, the open side of refrigerator body 10 is referred to as the front side of refrigerator 1, and the side opposite the opening is referred to as the rear side of refrigerator 1. Also, the up-down direction with respect to the direction of gravity when refrigerator 1 is placed on the floor in the position shown in Fig. 1 is referred to as the up-down direction of refrigerator 1. The left-right direction when refrigerator 1 is viewed from the front is referred to as the left-right direction of refrigerator 1, that is, the width direction, and the front-rear direction of refrigerator 1 is referred to as the depth direction of refrigerator 1.

[0010] The refrigerator 1 is mainly composed of a refrigerator body 10. The refrigerator body 10 is composed of a rectangular box having thermal insulation properties and an open front. The refrigerator body 10 is provided with a thermal insulation material composed of a thermal insulation member such as a foamed insulation material such as rigid urethane foam or a vacuum insulation panel inside each wall portion constituting the box.

[0011] The refrigerator body 10 is divided into a plurality of storage compartments for storing items. The refrigerator 1 includes, for example, a refrigeration compartment 11, a vegetable compartment 12, an ice-making compartment 13, a small freezer compartment 14, and a freezer compartment 15 as storage compartments. The refrigeration compartment 11 and the vegetable compartment 12 are all storage compartments in the refrigeration temperature range, and are cooled to, for example, about 1 to 5°C. On the other hand, the ice-making compartment 13, the small freezer compartment 14, and the freezer compartment 15 are storage compartments in the freezing temperature range, and are cooled to, for example, -18°C or lower. The refrigeration temperature range and the freezing temperature range are temperature ranges suitable for storing items in a refrigerated or frozen state.

[0012] The refrigerator compartment 11 is provided on the top level of the refrigerator body 10. The vegetable compartment 12 is provided below the refrigerator compartment 11. The ice-making compartment 13 and the small freezer compartment 14 are provided side by side on the left and right below the vegetable compartment 12. The freezer compartment 15 is provided below the ice-making compartment 13 and the small freezer compartment 14, that is, on the bottom level of the refrigerator body 10.

[0013] The refrigerator 1 includes a right-side refrigerator door 21a, a left-side refrigerator door 21b, a vegetable door 22, an ice-making door 23, a small freezer door 24, and a freezer door 25. Each of the doors 21a to 25 is formed by, for example, filling a heat insulating material inside a frame member made of metal or synthetic resin. The right-side refrigerator door 21a and the left-side refrigerator door 21b are, for example, hinged double doors that open and close the front opening of the refrigerator compartment 11. The refrigerator 1 is not limited to a configuration that includes double doors 21a and 21b, and may be a configuration that includes a so-called single-opening door. The vegetable door 22, the ice-making door 23, the small freezer door 24, and the freezer door 25 are all drawer-type doors that open and close the front openings of the vegetable compartment 12, the ice-making compartment 13, the small freezer compartment 14, and the freezer compartment 15, respectively. Although details are not shown, the vegetable compartment 12, the ice making compartment 13, the small freezer compartment 14, and the freezer compartment 15 each have containers that can be removed and inserted integrally with the vegetable compartment door 22, the ice making compartment door 23, the small freezer compartment door 24, and the freezer compartment door 25, respectively.

[0014] The refrigerator compartment 11 is provided with a special compartment 16. The special compartment 16 is configured to be able to maintain a temperature range within the refrigerator compartment 11 that is different from the refrigeration temperature range that is the temperature range of most of the refrigerator compartment 11. The special compartment 16 can be configured as a chilled compartment, for example, the inside of which can be maintained in a so-called chilled temperature range of around 0°C. The special compartment 16 is provided at the lowest level within the refrigerator compartment 11.

[0015] As shown in Fig. 2, the refrigerator body 10 has an insulating partition wall 17 and a non-insulating partition wall 18. The insulating partition wall 17 vertically separates the storage compartments 11 and 12 in the refrigerating temperature range from the storage compartments 13, 14, and 15 in the freezing temperature range in an insulated state. The non-insulating partition wall 18 vertically separates the refrigerator compartment 11 and the vegetable compartment 12 in the refrigerating temperature range storage compartments 11 and 12 without insulating them. Therefore, the refrigerator compartment 11 and the vegetable compartment 12 are thermally connected to each other.

[0016] The refrigerator 1 includes a refrigeration cycle 30. As shown in Fig. 2 and Fig. 3, the refrigeration cycle 30 includes a refrigeration cooler 31, a freezer cooler 32, a compressor 33, a switching valve 34, and a condenser and an expansion valve (not shown). The refrigeration cooler 31 is provided, together with a refrigeration blower 35, behind the refrigeration compartment 11 and the vegetable compartment 12, which are storage compartments in the refrigeration temperature range. The refrigeration cooler 31 and the refrigeration blower 35 have the function of generating cold air for cooling the refrigeration compartment 11 and the vegetable compartment 12, and supplying the cold air into the refrigeration compartment 11 and the vegetable compartment 12.

[0017] The freezing cooler 32, together with the freezing blower 36, is provided behind the ice making chamber 13, the small freezing chamber 14, and the freezing chamber 15, which are storage chambers in the freezing temperature range. The freezing cooler 32 and the freezing blower 36 have the function of generating cold air for cooling the ice making chamber 13, the small freezing chamber 14, and the freezing chamber 15, and supplying the cold air to the ice making chamber 13, the small freezing chamber 14, and the freezing chamber 15. The refrigeration cycle 30, the refrigeration blower 35, and the freezing blower 36 function as a cooling mechanism. As shown in FIG. 2, a drainage gutter 37 is provided below the freezing cooler 32. The drainage gutter 37 receives defrost water generated when the freezing cooler 32 is defrosted. The defrost water received in the drainage gutter 37 is discharged to a machine room outside the storage room through a drainage hose (not shown) connected to the drainage gutter 37.

[0018] The compressor 33 is provided, for example, in a machine room (not shown) at the bottom of the refrigerator 1. The compressor 33 compresses a refrigerant used to cool each of the storage chambers 11 to 15. The refrigerant compressed by the compressor 33 is supplied to the refrigeration cooler 31 and the freezing cooler 32. When the compressor 33 is stopped, no refrigerant is supplied to any of the coolers 31 and 32, and therefore cooling of each of the storage chambers 11 to 15 is stopped.

[0019] The switching valve 34 is for switching the supply of refrigerant to the refrigerating cooler 31 and the freezing cooler 32. The refrigeration cycle 30 generates cold air for cooling the storage chambers 11 and 12 in the refrigeration temperature range by switching the switching valve 34 to the refrigerating cooler 31 side and supplying the refrigerant to the refrigerating cooler 31 side. When the refrigerant is supplied to the refrigerating cooler 31 side, the cooling of the freezing cooler 32 is stopped, that is, the cooling of the ice making chamber 13, the small freezing chamber 14, and the freezing chamber 15 is stopped. On the other hand, the refrigeration cycle 30 generates cold air for cooling the storage chambers 13, 14, and 15 in the freezing temperature range by switching the switching valve 34 to the freezing cooler 32 side and supplying the refrigerant to the freezing cooler 32 side. When the refrigerant is supplied to the freezing cooler 32 side, the cooling of the refrigerating cooler 31 is stopped, that is, the cooling of the refrigerating chamber 11 and the vegetable chamber 12 is stopped. The refrigerator 1 is not limited to the configuration including the two coolers 31, 32, and may be configured to generate cold air for cooling each of the storage chambers 11-15 using one cooler.

[0020] As shown in Fig. 3, the refrigerator 1 includes a control unit 40, a door opening / closing sensor 41, an internal temperature sensor 42, a cooler temperature sensor 43, a timer unit 44, a defrost heater 51, and a gutter heater 52. The door opening / closing sensor 41, the internal temperature sensor 42, the cooler temperature sensor 43, the timer unit 44, the defrost heater 51, and the gutter heater 52 are each electrically connected to the control unit 40. The control unit 40 is mainly composed of a microcomputer having storage areas such as a CPU, ROM, RAM, and a rewritable flash memory. The control unit 40 controls the overall operation of the refrigerator 1.

[0021] A plurality of door opening / closing sensors 41 are provided corresponding to the doors 21a to 25, and have a function of detecting the opening / closing state of each of the doors 21a to 25. The door opening / closing sensor 41 functions as a door opening / closing detection unit. The inside temperature sensor 42 and the cooler temperature sensor 43 are composed of, for example, a thermistor. The inside temperature sensor 42 detects the temperature of the storage chambers 13, 14, and 15 in the freezing temperature range. The inside temperature sensor 42 is provided, for example, in the freezing chamber 15, and detects the temperature in the freezing chamber 15. The inside temperature sensor 42 functions as an inside temperature detection unit. The cooler temperature sensor 43 is provided, for example, around the freezing cooler 32, and detects the temperature of the freezing cooler 32. The cooler temperature sensor 43 functions as a cooler temperature detection unit. The clock unit 44 has a function of measuring the elapsed time from a certain point in time that is a reference. The time means the length of time from a certain point in time to a certain point in time.

[0022] The defrost heater 51 and the gutter heater 52 have a function of defrosting the cryocooler 32 by generating heat upon receiving power supply from an external power source (not shown). The defrost heater 51 functions as a first heating section, and the gutter heater 52 functions as a second heating section. The defrost heater 51 is composed of, for example, a pipe heater or a glass tube heater, and is provided around the cryocooler 32, in this case, in front, behind, and below the cryocooler 32. In this embodiment, the defrost heater 51 is provided in contact with or in close proximity to the cooling fins 32a that form part of the cryocooler 32, as shown in Figs. 4 and 5. Therefore, the defrost heater 51 directly defrosts the frost adhering to the cryocooler 32.

[0023] As shown in Figs. 4 and 5, the gutter heater 52 is, for example, a plate heater, and is provided at the bottom of the drain gutter 37. In this embodiment, the gutter heater 52 is formed in a shape that fits the bottom surface of the drain gutter 37. The gutter heater 52 indirectly defrosts frost adhering to the cryocooler 32. Here, when frost adheres to the cryocooler 32, the frost tends to start adhering from the bottom of the cryocooler 32. Since the gutter heater 52 is located below the cryocooler 32, it is effective in melting frost that occurs at the bottom of the cryocooler 32 in the early stage of frost formation on the cryocooler 32. In addition, the gutter heater 52 prevents defrost water generated during defrosting of the cryocooler 32, which is received in the drain gutter 37, from freezing in the drain gutter 37, and allows the defrost water to be discharged from the drain gutter 37 in a liquid state.

[0024] As described above, the gutter heater 52 is provided at a position below and away from the refrigeration cooler 32. That is, the gutter heater 52 is provided at a position farther away from the refrigeration cooler 32 than the defrost heater 51. In the present embodiment, the rated output of the gutter heater 52 is set to be smaller than the rated output of the defrost heater 51. In other words, the rated output of the defrost heater 51 is set to be larger than the rated output of the gutter heater 52. Therefore, the defrost heater 51 and the gutter heater 52 have different defrosting capabilities for the refrigeration cooler 32. That is, the refrigerator 1 includes a plurality of heaters 51, 52 having different defrosting capabilities for the refrigeration cooler 32. The defrost heater 51 has a higher defrosting capability for the refrigeration cooler 32 than the gutter heater 52. In other words, the gutter heater 52 has a lower defrosting capability for the refrigeration cooler 32 than the defrost heater 51. The defrosting capacity means the capacity to melt the frost adhering to the cryocooler 32, and can be expressed, for example, by the amount of frost adhering to the cryocooler 32 melted per unit time. The rated outputs of the defrost heater 51 and the gutter heater 52 may be set to be the same.

[0025] The control unit 40 drives the defrost heater 51 and the gutter heater 52 individually to defrost the freezer cooler 32. In defrosting the freezer cooler 32, the control unit 40 can execute complete defrost control and partial defrost control as shown in Fig. 6. Note that the waveform illustrated with the symbol Tf in Fig. 6 indicates the change over time of the temperature in the freezer compartment 15, i.e., the temperature detected by the inside temperature sensor 42. Also, the waveform illustrated with the symbol Te in Fig. 6 indicates the change over time of the temperature of the freezer cooler 32, i.e., the temperature detected by the cooler temperature sensor 43. In the following description, for convenience, it is assumed that the cold air generated by the freezer cooler 32 is supplied to the freezer compartment 15 among the storage compartments 13, 14, and 15 in the freezing temperature range.

[0026] The complete defrost control is a well-known control that is executed, for example, when the accumulated operating time of the compressor 33 reaches a reference time. The complete defrost control is a control that assumes that frost adhering to the refrigeration cooler 32 is completely removed. The complete defrost control includes, for example, a control that simultaneously drives the defrost heater 51 and the gutter heater 52 until the detected temperature Te of the cooler temperature sensor 43 reaches the defrost temperature Td while the compressor 33 and the refrigeration blower 36 are stopped. The defrost temperature Td is set, for example, in the range of 3°C to 15°C.

[0027] The partial defrost control is control that is executed, for example, when a predetermined condition for frost deterioration of the cryocooler 32 is satisfied, until the predetermined condition is resolved. The partial defrost control is control intended to alleviate frost deterioration caused by frost adhering to the cryocooler 32, that is, to partially defrost the frost adhering to the cryocooler 32. Frosting deterioration refers to a state in which the cooling function of the cryocooler 32 is reduced as frost advances on the cryocooler 32.

[0028] The cycle of supplying cold air to the freezer compartment 15 and stopping the supply of cold air in the partial defrost control is performed in the same manner as the control performed for cooling the freezer compartment 15 in normal times, that is, the cycle of normal control. In this embodiment, the partial defrost control is performed after a certain period of time, for example, several hours, has elapsed after the complete defrost control has been performed. In other words, the partial defrost control is configured not to be performed within the certain period of time after the complete defrost control has been performed.

[0029] Here, when frost deterioration occurs in the freezer cooler 32, the temperature of the freezer cooler 32 drops over time. Then, as the cooling function is reduced by frost adhesion to the freezer cooler 32, the temperature in the freezer compartment 15 rises. Thus, the predetermined condition for the freezer cooler 32 to deteriorate due to frost includes a temperature difference ΔT between the detected temperature Tf of the inside temperature sensor 42 and the detected temperature Te of the cooler temperature sensor 43 during cooling in the freezer compartment 15 exceeding a threshold value, for example, 7°C. In this way, the temperature difference ΔT can be used as an index for determining the progress of frost deterioration. Then, the partial defrost control is executed, for example, until the temperature difference ΔT becomes equal to or less than the threshold value. The temperature difference ΔT may be acquired, for example, at the start or end of each cooling in the freezer compartment 15, or may be acquired for each predetermined number of cooling periods.

[0030] Furthermore, the predetermined condition for the frost formation deterioration of the refrigeration cooler 32 may include a condition in which the current temperature difference ΔTt during cooling in the freezing chamber 15 is larger than the previous temperature difference ΔTl during cooling in the freezing chamber 15. The state in which the freezing chamber 15 is being cooled means, for example, a state in which the refrigerant supplied from the compressor 33 is flowing to the refrigeration cooler 32. The comparison of the current temperature difference ΔTt with the previous temperature difference ΔTl may use the previous and current temperature differences ΔTt, ΔTl acquired at a predetermined period, i.e., at a preset time interval, or may use the previous and current temperature differences ΔTt, ΔTl acquired at the same timing within each period in which the refrigerant supplied from the compressor 33 is flowing to the refrigeration cooler 32.

[0031] In partial defrost control, for example, in a state where the supply of refrigerant to the refrigeration cooler 32 side is stopped, the gutter heater 52 is driven to suppress the drive of the defrost heater 51. A mode of suppressing the drive of the defrost heater 51 includes, for example, stopping the drive of the defrost heater 51. That is, in partial defrost control, the total drive time of the gutter heater 52 is made longer than the total drive time of the defrost heater 51. The total drive time can be calculated by multiplying the drive time of one time by the number of times of drive. The drive time td of one time of the gutter heater in partial defrost control can be set to the same as the time for supplying cold air into the freezer compartment 15 in one cycle of supplying cold air into the freezer compartment 15 and stopping the supply of cold air. In this case, the drive time td is set to, for example, about 20 to 40 minutes. The drive time td may be different from the time for supplying cold air into the freezer compartment 15 in one cycle.

[0032] The partial defrost control may be executed based on the detection result of the door opening / closing sensor 41. In this case, the control unit 40 executes the partial defrost control on the condition that the door opening / closing sensor 41 does not detect the opening of the freezer door 25 for a predetermined time tc, for example, 30 minutes. This makes it possible to obtain the temperature difference ΔT in a state that is not affected by the opening / closing of the freezer door 25, and therefore makes it possible to accurately determine whether or not the freezer cooler 32 has deteriorated due to frost formation.

[0033] In partial defrost control, the control unit 40 can drive the gutter heater 52 after the waiting time tw, for example, one minute, has elapsed since the cooling in the freezer compartment 15 was stopped. This allows the cooling in the freezer compartment 15 to be stopped and after the waiting time tw has elapsed, that is, after waiting for a certain amount of refrigerant to escape from the freezer cooler 32, and then defrosts the freezer cooler 32 using the heat from the gutter heater 52, thereby hastening the melting of frost.

[0034] In addition, when the control unit 40 determines to start defrosting of the refrigeration cooler 32 because the temperature difference ΔT exceeds the threshold value, for example, the control unit 40 can execute pump-down, which is an operation for collecting the refrigerant on the compressor 33 side by operating the compressor 33 for a while with the switching valve 34 closed, as a preparation for defrosting. Then, the control unit 40 stops driving the compressor 33 after executing pump-down. The period during which the pump-down is executed corresponds to the period during which the cooling in the freezing chamber 15 is stopped because the switching valve 34 is closed. The period during which the pump-down is executed is set within a range of about 20 seconds to 3 minutes, for example. Therefore, the waiting time tw can include the period during which the pump-down is executed. In addition, the partial defrost control is not limited to a configuration in which it is executed in a state in which the supply of the refrigerant to the refrigeration cooler 32 side is stopped, and may be a configuration in which it is executed before the end of cooling, such as at the end of cooling in the freezing chamber 15.

[0035] Next, an example of the control content when partial defrost control is performed will be described with reference to Fig. 7. When the control unit 40 starts the process (START), in step S11, it determines whether or not the closed time of the freezer door 25 has exceeded a predetermined time tc based on the detection result of the door open / close sensor 41. If the closed time of the freezer door 25 has exceeded the predetermined time tc (YES in step S11), the control unit 40 shifts the process to step S12 and determines whether or not the temperature difference ΔT has exceeded a threshold value, for example, 7°C.

[0036] If the temperature difference ΔT does not exceed the threshold value (NO in step S12), the control unit 40 shifts the process to step S13, cancels the execution of partial defrost control, switches the control content to normal control, and returns the process to step S11. On the other hand, if the temperature difference ΔT exceeds the threshold value (YES in step S12), the control unit 40 shifts the process to step S14, and at a preset time, for example, operates the switching valve 34 to stop the supply of refrigerant to the refrigeration cooler 32 side, thereby stopping the cooling inside the freezing chamber 15.

[0037] Next, in step S15, the control unit 40 determines whether or not the standby time tw has elapsed since cooling inside the freezer compartment 15 was stopped. If the standby time tw has elapsed (YES in step S15), the control unit 40 proceeds to step S16 and drives the gutter heater 52. Thereafter, in step S17, the control unit 40 determines whether or not the drive time td has elapsed since driving the gutter heater 52. If the drive time td has elapsed (YES in step S17), the control unit 40 proceeds to step S18 and stops driving the gutter heater 52.

[0038] Next, in step S19, at a preset time, the control unit 40 operates, for example, the switching valve 34 to start supplying the refrigerant to the refrigeration cooler 32 side, and resumes cooling inside the freezing chamber 15. Thereafter, the control unit 40 returns the process to step S12, and repeats the subsequent processes.

[0039] According to the embodiment described above, the refrigerator 1 includes the freezer compartment 15, the freezer cooler 32, the heaters 51 and 52, and the control unit 40. The freezer cooler 32 generates cold air for cooling the freezer compartment 15. The heaters 51 and 52 have different defrosting capacities for the freezer cooler 32. The control unit 40 can defrost the freezer cooler 32 by individually driving the heaters 51 and 52. The heaters 51 and 52 include a defrost heater 51 and a gutter heater 52 having a lower defrosting capacity than the defrost heater 51. The control unit 40 drives the gutter heater 52 to suppress driving of the defrost heater 51 when a predetermined condition is satisfied in which the cooling function of the freezer cooler 32 is reduced due to frost formation.

[0040] This makes it possible to efficiently mitigate frost deterioration of the cryocooler 32 while suppressing a temperature rise in the storage chambers 13, 14, 15 in the freezing temperature range that accompanies defrosting of the cryocooler 32. This makes it possible to efficiently prevent problems with cooling of the storage chambers 13, 14, 15 that are caused by frost deterioration of the cryocooler 32.

[0041] The refrigerator 1 further includes an internal temperature sensor 42 and a cooler temperature sensor 43. The internal temperature sensor 42 detects the temperature inside the freezer compartment 15. The cooler temperature sensor 43 detects the temperature of the freezer cooler 32. The predetermined condition under which the cooling function of the freezer cooler 32 is reduced due to frosting includes a condition in which a temperature difference ΔT between the detected temperature Tf of the internal temperature sensor 42 and the detected temperature Te of the cooler temperature sensor 43 exceeds a threshold value. According to this, by determining the progress of the frost deterioration based on the temperature difference ΔT, the frost deterioration of the freezer cooler 32 can be efficiently mitigated.

[0042] Further, the predetermined condition under which the cooling function of the cryocooler 32 is reduced due to frosting includes a condition in which the current temperature difference ΔTt during cooling in the freezer compartment 15 is larger than the previous temperature difference ΔTl during cooling in the freezer compartment 15. According to this, the degree of frost deterioration is judged based on whether the temperature difference ΔT is expanding, that is, the growth of frost is estimated, thereby enabling more accurate mitigation of frost deterioration of the cryocooler 32. Furthermore, when the temperature difference ΔT is decreasing, that is, when it is estimated that the frost is not growing, defrosting of the cryocooler 32 using the gutter heater 52 is not performed, and thus the temperature rise in the freezer compartment 15 due to the defrosting can be further suppressed.

[0043] When a predetermined condition is satisfied that the cooling function of the cryocooler 32 is reduced due to frost, the control unit 40 drives the gutter heater 52 after the standby time tw has elapsed since the cooling in the freezer compartment 15 was stopped. This makes it easier to melt the frost that has adhered to the cryocooler 32 by heating the cryocooler 32 using the gutter heater 52 in a state in which the refrigerant has been drained from the cryocooler 32 due to the elapse of the standby time tw. This allows the frost on the cryocooler 32 to be quickly eliminated in a short time.

[0044] Second embodiment Next, a second embodiment will be described with reference to FIG. 8. In the second embodiment, the control contents when the partial defrost control is performed are different from those in the first embodiment. In the second embodiment, the control unit 40 executes the control contents shown in FIG. 8 instead of the control contents shown in FIG. 7. In the control contents shown in FIG. 8, steps S21 to S27 are added instead of steps S14 to S19 in the control contents shown in FIG. 7. In the second embodiment, the control unit 40 operates the switching valve 34 to stop the supply of the refrigerant to the refrigeration cooler 32 side and executes the pump-down, and then stops the compressor 33 and drives the gutter heater 52. Specifically, when the temperature difference ΔT exceeds the threshold value (YES in step S12 in FIG. 8), the control unit 40 shifts the process to step S21, operates the switching valve 34 to stop the supply of the refrigerant to the refrigeration cooler 32 side, and executes the pump-down.

[0045] Next, in step S22, the control unit 40 stops the compressor 33. Thereafter, in step S23, the control unit 40 drives the gutter heater 52. Next, in step S24, the control unit 40 determines whether or not the drive time td has elapsed since the gutter heater 52 was driven. If the drive time td has not elapsed (NO in step S24), the control unit 40 proceeds to step S25 and determines whether or not the detected temperature Te of the cooler temperature sensor 43 exceeds the stop temperature Ts, for example, 15°C.

[0046] If the detected temperature Te exceeds the stop temperature Ts (YES in step S25), the control unit 40 proceeds to step S26 and stops driving the gutter heater 52. That is, when the control unit 40 drives the gutter heater 52 after stopping the compressor 33, the control unit 40 stops driving the gutter heater 52 if the detected temperature Te of the cooler temperature sensor 43 exceeds the stop temperature Ts. The stop temperature Ts is set to a temperature lower than the defrost temperature Td. Preferably, the stop temperature Ts is set in the negative temperature zone.

[0047] On the other hand, if the drive time td has elapsed (YES in step S24), the control unit 40 shifts the process to step S26 and stops driving the gutter heater 52. Next, in step S27, at a preset time, the control unit 40 operates, for example, the switching valve 34 to start supplying refrigerant to the refrigeration cooler 32 side and resumes cooling inside the freezing chamber 15. Thereafter, the control unit 40 returns the process to step S12 and repeats the subsequent processes.

[0048] According to the second embodiment, the same effects as those of the first embodiment can be obtained. In addition, the timing for ending the defrosting of the cryocooler 32 using the gutter heater 52 can be determined based on the temperature of the cryocooler 32. This can prevent the cryocooler 32 from becoming excessively hot due to the heat from the gutter heater 52. This can prevent the cold air generated by the cryocooler 32 from becoming too hot after partial defrosting. This can prevent the temperature in the storage chambers 13, 4, and 15 from rising, and can smoothly defrost the cryocooler 32.

[0049] Third embodiment Next, a third embodiment will be described with reference to FIG. 9. In this third embodiment, the contents of the partial defrost control are different from those of the above-mentioned embodiments. In the third embodiment, as shown in FIG. 9, in the partial defrost control, the defrost heater 51 is used in addition to the gutter heater 52 to defrost the freezing cooler 32. Specifically, in the partial defrost control, the control unit 40 stops the cooling in the freezing chamber 15 and drives the defrost heater 51, and then stops the driving of the defrost heater 51 and drives the gutter heater 52 when a predetermined time tj (e.g., one minute) or when the detected temperature Te of the cooler temperature sensor 43 reaches a predetermined temperature (e.g., 6°C to 10°C). Then, when driving the gutter heater 52, the defrost heater 51 is stopped. Note that the period during which the defrost heater 51 is driven and the period during which the gutter heater 52 is driven may overlap.

[0050] According to the third embodiment, defrosting is performed using the defrost heater 51 with high defrosting capacity, and then defrosting is switched to using the gutter heater 52, thereby enabling defrosting of the refrigeration cooler 32 to be performed efficiently in a short time.

[0051] Next, a fourth embodiment will be described with reference to FIG. 10. In this fourth embodiment, the content of the partial defrost control is different from each of the above-mentioned embodiments. In the fourth embodiment, as shown in FIG. 10, in the partial defrost control, the refrigeration cooler 32 is defrosted using the refrigeration blower 36 in addition to the gutter heater 52. That is, in the partial defrost control in this embodiment, the control unit 40 drives the gutter heater 52 and also drives the refrigeration blower 36. The period during which the refrigeration blower 36 is driven is set to at least partially overlap with the period during which the gutter heater 52 is driven. In this case, the period during which the refrigeration blower 36 is driven may be the same as the period during which the gutter heater 52 is driven, or may be shorter than the period during which the refrigeration blower 36 is driven.

[0052] In addition, when driving the refrigeration blower 36 together with the gutter heater 52, the control unit 40 sets the rotation speed of the refrigeration blower 36 to be equal to or lower than the lowest rotation speed of the refrigeration blower 36 during cooling of the freezer compartment 15. Here, when the refrigeration blower 36 is driven together with the gutter heater 52 at or lower than the lowest rotation speed, the amount of heat transferred to the storage compartments 13, 14, and 15 can be reduced compared to when the defrost heater 51 is driven. The advantage of promoting defrosting of the refrigeration cooler 32 when the refrigeration blower 36 is driven together with the gutter heater 52 at or lower than the lowest rotation speed is more significant than the disadvantage of temperature rise in the storage compartments 13, 14, and 15. For this reason, by driving the refrigeration blower 36 together with the gutter heater 52 at or lower than the lowest rotation speed, it is possible to promote defrosting of the refrigeration cooler 32 while suppressing the temperature rise in the storage compartments 13, 14, and 15.

[0053] According to the fourth embodiment, by forming an air flow by the refrigeration blower 36, it is possible to equalize the temperature in the space in which the cryocooler 32 is provided, and to promote defrosting of the cryocooler 32.

[0054] The above-described embodiments can be combined with each other, or only the characteristic parts of two or more embodiments can be extracted and combined. The refrigerator 1 may be configured to include a weighing scale (not shown) capable of measuring the weight of the freezer cooler 32. The measurement result of the weighing scale may be included in the predetermined condition for the freezer cooler 32 to deteriorate due to frost formation. In this case, the control unit 40 may determine whether or not to execute partial defrost control by detecting the amount of frost adhesion, i.e., the amount of frost formation, based on the weight of the freezer cooler 32 measured by the weighing scale.

[0055] The above-described embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0056] 1...refrigerator, 13...ice-making compartment (storage compartment), 14...small freezer compartment (storage compartment), 15...freezer compartment (storage compartment), 32...freezer cooler (cooler), 40...control unit, 51...defrost heater (first heating unit), 52...gutter heater (second heating unit)

Claims

1. A storage room; A cooler that generates cold air for cooling the storage chamber; A plurality of heating units each having a different defrosting capacity for the cooler; A control unit capable of individually driving the plurality of heating units to defrost the cooler, The plurality of heating units include a first heating unit and a second heating unit having a defrosting capacity lower than that of the first heating unit, The control unit drives the second heating unit and suppresses driving of the first heating unit when a predetermined condition is satisfied in which a cooling function of the cooler is reduced due to frost formation. refrigerator.

2. An internal temperature detection unit that detects the temperature inside the storage chamber; A cooler temperature detection unit that detects the temperature of the cooler, The predetermined condition in which the cooling function of the cooler is reduced due to frosting includes a temperature difference between the temperature detected by the internal temperature detection unit and the temperature detected by the cooler temperature detection unit exceeding a threshold value.

2. The refrigerator according to claim 1.

3. The predetermined condition under which the cooling function of the cooler is reduced due to frost includes that the current temperature difference during cooling of the storage chamber is larger than the previous temperature difference during cooling of the storage chamber. The refrigerator according to claim 2.

4. The control unit drives the second heating unit after a standby time has elapsed since the cooling of the storage chamber is stopped when a predetermined condition in which the cooling function of the cooler is reduced due to frost is satisfied.

2. The refrigerator according to claim 1.

5. The storage chamber further includes a compressor for compressing a refrigerant used for cooling the storage chamber, When a predetermined condition in which a cooling function of the cooler is reduced due to frost is satisfied, and when the second heating unit is driven after stopping the drive of the compressor, the control unit stops the drive of the second heating unit when a drive time has elapsed since the second heating unit was driven or when the detected temperature of the cooler temperature detection unit exceeds a stop temperature.

2. The refrigerator according to claim 1.

6. The control unit drives the second heating unit after a predetermined time has elapsed since the cooling of the storage chamber is stopped and the first heating unit is driven, or when the temperature detected by the cooler temperature detection unit reaches a predetermined temperature.

2. The refrigerator according to claim 1.

7. When the control unit drives the second heating unit after the predetermined time has elapsed since the cooling of the storage chamber is stopped and the first heating unit is driven, or when the temperature detected by the cooler temperature detection unit reaches the predetermined temperature, the control unit stops the first heating unit. The refrigerator according to claim 6.

8. The cooling system further includes a blower that blows the cold air generated by the cooler, The second heating unit is provided at a position farther from the cooler than the first heating unit, The control unit drives the second heating unit and the blower.

2. The refrigerator according to claim 1.

9. When driving the second heating unit and the blower, the control unit sets a rotation speed of the blower to be equal to or lower than a lowest rotation speed of the blower during cooling of the storage chamber. The refrigerator according to claim 8.

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