refrigerator

Abstract

To perform driving and defrosting operation of a compressor at an appropriate timing by determining whether frost adheres to a cooler or not with respect to a refrigerator which detects a refrigerant temperature of an entrance of the cooler.SOLUTION: A refrigerator includes: a compressor (90); a cooler (25); a cooling chamber (45) having the cooler arranged therein; a first sensor (TS1) for detecting an inflow temperature of a refrigerant flowing into the cooler; a second sensor (TS2) for detecting an outflow temperature of a refrigerant flowing out from the cooler; a heater (35) for removing frost adhering to the cooler; a control device (80) for controlling the compressor and the heater; and a fan (15) arranged in the cooling chamber. The control device acquires (S102) a detection result of the first sensor (TS1), acquires (S103) a detection result of the second sensor (TS2), and controls the compressor and the heater based on a temperature difference between the inflow temperature and the outflow temperature and on one or more thresholds.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a refrigerator that cools using a refrigeration cycle.

Background Art

[0002] Conventionally, a refrigerator that refrigerates and freezes foods in the cabinet using a refrigeration cycle system including a compressor has been known. Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2015-038409) describes a refrigerator that has a refrigerating chamber and a freezing chamber and blows air cooled in a cooling chamber into each of the refrigerating chamber and the freezing chamber. In the refrigerator of Patent Document 1, based on the temperature difference between the inlet and outlet of the refrigerant of the cooler, the state inside the cabinet is determined, and dampers between the cooling chamber and the refrigerating chamber and between the cooling chamber and the freezing chamber are controlled.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the refrigerator of Patent Document 1, the temperature inside the cabinet is appropriately adjusted by controlling the damper, but whether or not frost is attached to the cooler is not considered when determining the state inside the cabinet. In a state where frost is attached to the cooler, the heat exchange efficiency of the cooler is reduced, and the cooling capacity may not be sufficiently exhibited.

[0005] The present disclosure has been made to solve such problems, and an object thereof is to provide a refrigerator that detects the refrigerant temperature at the inlet and outlet of a cooler, determines whether or not frost is attached to the cooler, and can drive a compressor and perform a defrosting operation at an appropriate timing.

Means for Solving the Problems

[0006] The refrigerator in the present disclosure includes a compressor, a cooler, a cooling chamber in which the cooler is disposed, a first sensor that detects the inflow temperature of the refrigerant flowing into the cooler, a second sensor that detects the outflow temperature of the refrigerant flowing out of the cooler, a heater that removes frost adhering to the cooler, a control device that controls the compressor and the heater, and a fan disposed in the cooling chamber. The control device acquires the detection result of the first sensor, acquires the detection result of the second sensor, and controls the compressor and the heater based on the temperature difference between the inflow temperature and the outflow temperature and at least one threshold value.

Advantages of the Invention

[0007] In the refrigerator of the present disclosure, it is possible to determine whether or not frost is adhering to the cooler and perform the driving of the compressor and the defrosting operation at appropriate timing.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the technical idea according to the present disclosure will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0010] Embodiment 1. <Overall Configuration of Refrigerator> FIG. 1 is a transparent view showing a cross-section of the refrigerator 10. FIG. 1(A) is a transparent view when the refrigerator 10 is viewed from the front. FIG. 1(B) is a transparent view when the refrigerator 10 is viewed from the side. The refrigerator 10 in the present embodiment has a hexahedral shape.

[0011] When the refrigerator 10 is installed on the floor surface, the vertical direction is defined as the Z-axis direction, and a plane perpendicular to the Z-axis direction is defined as the XY plane. Also, in each figure, the positive direction of the Z-axis may be referred to as the upper surface side or the upper side, and the negative direction may be referred to as the lower surface side or the lower side. The refrigerator 10 includes a refrigerator main body 100 including a heat-insulating box body 20. The heat-insulating box body 20 includes a vacuum heat-insulating material 21 and a foam heat-insulating material 22. The vacuum heat-insulating material 21 and the foam heat-insulating material 22 suppress the entry of heat from the outside air and heat from a heat-insulating body condenser (not shown). The heat-insulating box body 20 includes an outer box 10S and an inner box 10I. The inner box 10I is disposed inside the outer box 10S. The outer box 10S is made of steel. The inner box 10I is made of resin.

[0012] Inside the refrigerator main body 100, a refrigerating chamber R, an ice-making chamber I, a switching chamber S, a vegetable chamber V, and a freezing chamber F are formed as storage chambers. Hereinafter, the refrigerating chamber R, the ice-making chamber I, the switching chamber S, the vegetable chamber V, and the freezing chamber F may be collectively referred to as each storage chamber R to F. Each storage chamber R to F is partitioned by partition members 50a to 50f. The partition members 50a to 50f are provided to suppress heat transfer between the storage chambers R to F.

[0013] The interior of the refrigerator compartment R is partitioned into a plurality of spaces in the vertical direction by a plurality of shelf boards. The space below the lowermost shelf board is the chiller compartment Ch. A rotary refrigerator door for opening and closing the opening formed in the front surface of the refrigerator compartment R is provided. The refrigerator door is a double-opening type composed of a right door and a left door. A thermistor Rt disposed in the refrigerator compartment R detects the temperature of the air in the refrigerator compartment R.

[0014] The switching compartment S is disposed below the refrigerator compartment R. The cold storage temperature zone of the switching compartment S can be set and switched to any one of a plurality of temperature zones. The plurality of temperature zones selectable as the cold storage temperature zone of the switching compartment S are a freezing temperature zone (for example, about -15°C), a refrigerating temperature zone (for example, about 3°C), a chiller temperature zone (for example, about 0°C), a soft freezing temperature zone (for example, about -8°C), and the like. A thermistor St disposed in the switching compartment S detects the temperature of the air in the switching compartment S.

[0015] The ice-making compartment I is disposed adjacent to the switching compartment S below the refrigerator compartment R. A thermistor It disposed in the ice-making compartment I detects the temperature of the air in the ice-making compartment I. The vegetable compartment V is disposed below the switching compartment S and the ice-making compartment I. The vegetable compartment V is mainly for storing vegetables, large-capacity plastic bottles, and the like. A thermistor Vt disposed in the vegetable compartment V detects the temperature of the air in the vegetable compartment V.

[0016] The freezer compartment F is below the vegetable compartment V and is disposed at the lowermost stage of the refrigerator body 100. The freezer compartment F is mainly used for freezing and storing storage targets over a relatively long period. A thermistor Ft disposed in the freezer compartment F detects the temperature of the air in the freezer compartment F.

[0017] Each of the switching compartment S, the ice-making compartment I, the vegetable compartment V, and the freezer compartment F is opened and closed by a drawer-type door. The drawer-type door can be opened and closed in the Y-axis direction by sliding a frame fixed to the door with respect to rails horizontally formed on the left and right inner wall surfaces of each of the switching compartment S, the ice-making compartment I, the vegetable compartment V, and the freezer compartment F.

[0018] The cooling chamber 45 is formed at a position on the negative Y-axis side of the vegetable chamber V in the refrigerator 10. In the cooling chamber 45, an internal fan 15, a cooler 25, a heater 35, and a thermistor Qt are arranged. The cooler 25 cools the air around the cooler 25. The internal fan 15 sends the air cooled by the cooler 25 to each storage chamber R to F. The heater 35 raises the temperature of the cooler 25 to melt and remove the frost adhering to the cooler 25. A machine room 95 in which a compressor 90 is arranged is formed on the negative Y-axis side of the freezer chamber F.

[0019] As shown in FIG. 1(B), a damper device Rd is provided between the cooling chamber 45 and the refrigerating chamber R. A damper device Sd is provided between the cooling chamber 45 and the switching chamber S. A damper device Vd is provided between the cooling chamber 45 and the vegetable chamber V. A damper device Fd is provided between the cooling chamber 45 and the freezer chamber F. Further, in the refrigerating chamber R, a damper device Rd2 is provided in the chilled chamber Ch.

[0020] As shown in FIG. 1(A), a damper device Id is provided between the cooling chamber 45 and the ice-making chamber I. The damper device Id is arranged on the negative X-axis side of the damper device Sd in FIG. 1(B). The damper device Id is only shown in FIG. 1(A), and in FIG. 1(A), the illustrations of the damper devices Rd, Sd, Vd, and Fd are omitted. The damper devices Rd, Sd, Vd, Fd, Rd2, and Id are configured such that the opening degree of the air duct in which each damper device is arranged can be adjusted. Hereinafter, the damper devices Rd, Sd, Id, Vd, and Fd may be collectively referred to as the damper devices Rd to Fd.

[0021] A control room 65 in which a control device 80 is arranged is formed on the positive Z-axis side of the refrigerator body 100 and in the negative Y-axis direction. The control device 80 controls the compressor 90, the heater 35, and the internal fan 15. Further, the control device 80 controls the opening degree of the damper devices Rd to Fd. When the damper devices Rd to Fd are in the closed state, they block the flow of air blown from the cooling chamber 45, and when they are in the open state, they allow the air blown from the cooling chamber 45 to pass through.

[0022] The control device 80 controls the opening degrees of the damper devices Rd, Sd, Id, Vd by comparing the target temperature ranges set for each of the refrigerator compartment R, the switching compartment S, the ice-making compartment I, and the vegetable compartment V with the detected temperatures of the thermistors in each of the refrigerator compartment R, the switching compartment S, the ice-making compartment I, and the vegetable compartment V. The control device 80 sets different target temperature ranges for each of the refrigerator compartment R, the switching compartment S, the ice-making compartment I, the vegetable compartment V, and the freezer compartment F.

[0023] The target temperature range is a temperature range including a certain range and includes a lower limit temperature and an upper limit temperature. For example, a target temperature range between +2°C and +7°C is set for the refrigerator compartment R. Hereinafter, the center of the target temperature range may be simply referred to as the "target temperature". That is, the target temperature of the refrigerator compartment R is 5°C.

[0024] When the detected value of the thermistor falls below the lower limit temperature of the set target temperature range, the control device 80 controls the corresponding damper device to the closed state to suppress the excessive cooling of the storage compartment. Further, when the detected value of the thermistor exceeds the upper limit temperature of the set target temperature range, the control device 80 controls the corresponding damper device to the open state to allow the cooled air to flow in and maintain the temperature in the storage compartment within the target temperature range.

[0025] <Refrigeration cycle> FIG. 2 is a schematic diagram showing the refrigeration cycle used in the refrigerator 10. The refrigerator 10 includes, as a refrigeration cycle device, a compressor 90, a condenser 85, capillary tubes 30S, 30L, a cooler 25, a switching device 29, and an accumulator 49. In Embodiment 1, the refrigerator 10 includes a sensor TS1 for detecting the temperature of the refrigerant flowing into the cooler 25 and a sensor TS2 for detecting the outflow temperature of the refrigerant flowing out of the cooler 25.

[0026] The compressor 90 compresses the refrigerant, thereby changing the state of the refrigerant to a gaseous state at high temperature and high pressure and sending it to the condenser 85. The condenser 85 condenses the refrigerant in the gaseous state at high temperature and high pressure, changing the state of the refrigerant to a gas-liquid mixed state at high temperature and high pressure. The condenser 85 sends the refrigerant in the gas-liquid mixed state at high temperature and high pressure to either the capillary tube 30S or 30L.

[0027] The switching device 29 is a three-way valve. The control device 80 controls the switching device 29 to an open state or a closed state. The capillary tubes 30S and 30L decompress the refrigerant in the gas-liquid mixed state at high temperature and high pressure, changing it to a gas-liquid mixed state at low temperature and low pressure. The refrigerant in the gas-liquid mixed state at low temperature and low pressure that reaches the cooler 25 exchanges heat with the air around the cooler 25. As a result, the air around the cooler 25 is cooled. Also, due to the heat exchange in the cooler 25, the refrigerant changes from a gas-liquid mixed state at low temperature and low pressure to a gaseous state refrigerant at low temperature and low pressure. The cooler 25 sends the refrigerant in the gaseous state at low temperature and low pressure to the compressor 90.

[0028] In Embodiment 1, the sensor TS1 is a thermistor that detects the temperature of the pipe through which the refrigerant flowing into the cooler 25 passes. The refrigerant flowing into the cooler 25 means the refrigerant immediately before entering the cooler 25. For example, the sensor TS1 is disposed on the surface of the pipe connecting the cooler 25 and the capillary tubes 30S and 30L.

[0029] Also, the sensor TS2 is a thermistor that detects the temperature of the pipe through which the refrigerant flowing out of the cooler 25 passes. The refrigerant flowing out of the cooler 25 means the refrigerant immediately after being discharged from inside the cooler 25 to the outside of the cooler 25. For example, the sensor TS2 is disposed on the surface of the pipe connecting the cooler 25 and the accumulator 49.

[0030] The control device 80 calculates the temperature of the refrigerant flowing into the cooler 25 based on the detection result of the sensor TS1. Hereinafter, the temperature of the refrigerant flowing into the cooler 25 is simply referred to as the "inflow temperature". Further, the control device 80 calculates the temperature of the refrigerant flowing out of the cooler 25 based on the detection result of the sensor TS2. Hereinafter, the temperature of the refrigerant flowing out of the cooler 25 is simply referred to as the "outflow temperature". Note that the sensor TS1 may correspond to the "first sensor" in the present disclosure. The sensor TS2 may correspond to the "second sensor" in the present disclosure.

[0031] The accumulator 49 stores the surplus refrigerant among the refrigerant flowing into the compressor 90. In other words, the accumulator 49 is configured to be able to accumulate the refrigerant. As shown in FIG. 2, the accumulator 49 is disposed between the cooler 25 and the compressor 90. Note that the accumulator 49 is also referred to as a reservoir. The refrigerant flowing from the accumulator 49 into the compressor 90 is pressurized again by the compressor 90 and circulates through the refrigeration cycle.

[0032] The indoor fan 15 sends the air cooled by the cooler 25 to each of the storage chambers R to F by blowing the surrounding air. In FIG. 2, the path through which the air flows due to the drive of the indoor fan 15 is indicated by an arrow. In the refrigerating chamber R, the ice-making chamber I, the switching chamber S, and the vegetable chamber V, there are also provided air passages 1a, 2a, 3a, 4a through which cold air is blown from the cooling chamber 45 and air passages 1b, 2b, 3b, 4b through which the air returns to the cooling chamber 45.

[0033] When the damper devices Rd to Fd are in the open state, the cooled air returns to the cooler 25 after passing through each of the storage chambers R to F. In FIG. 2, the broken lines connecting the indoor fan 15, the damper devices Rd to Fd, and each of the storage chambers R to F indicate the air circulation path.

[0034] <Regarding the control device> FIG. 3 is a block diagram showing the circuit configuration of the refrigerator 10. As shown in FIG. 3, the control device 80 is connected to the heater 35, the compressor 90, the switching device 29, the internal fan 15, the damper devices Rd, Rd2, Id, Sd, Vd, Fd, and the thermistors Rt, It, St, Vt, Ft, Qt, TS1, TS2. FIG. 3 shows the connection relationship between the control device 80 and each component.

[0035] The control device 80 includes, for example, a microcomputer and includes a processor and a memory. The control device 80 executes a prescribed process by the processor executing a program stored in the memory, and comprehensively controls the refrigerator 10.

[0036] <Sensor Arrangement> FIG. 4 is a diagram for explaining the arrangement of the sensors TS1, TS2 in the first embodiment. FIG. 4 shows the internal fan 15, the cooler 25, the accumulator 49, and the compressor 90 stored in the machine room 95. The above-described foam heat insulating material 22 is disposed around the pipe connecting the accumulator 49 and the machine room 95. As described above, the sensor TS1 is disposed between the capillary tubes 30S, 30L and the cooler 25. Also, as shown in FIG. 4, the sensor TS2 is disposed between the accumulator 49 and the cooler 25.

[0037] In the first embodiment, the sensors TS1, TS2 are disposed at positions where they are hardly affected by the air circulation generated by the driving of the internal fan 15. In the example of the first embodiment, as shown in FIG. 4, the sensors TS1, TS2 are not disposed between the internal fan 15 and the cooler 25. More specifically, the region where the sensors TS1, TS2 are disposed is a region different from the region Rg1 shown in FIG. 4. The region Rg1 is the region between the internal fan 15 and the cooler 25.

[0038] As a result, the sensors TS1 and TS2 can be arranged at positions where the influence of the internal fan 15 that sucks up the air around the cooler 25 is reduced. Therefore, the sensors TS1 and TS2 in the first embodiment can detect the temperature of the refrigerant in the pipe more accurately. Note that the sensors TS1 and TS2 may be arranged at the end of the cooler 25 or the like where the influence of the suction of the internal fan 15 is reduced by a defrost prevention spacer or the like.

[0039] <P-h diagram> FIG. 5 is a P-h diagram in the first embodiment. The P-h diagram in FIG. 5 shows a refrigeration cycle R1 indicating the state transition of the refrigerant in the present embodiment. The sensor TS1 arranged on the inlet side of the cooler 25 detects the temperature of the refrigerant at the position indicated as point T1 in the refrigeration cycle R1 of FIG. 5. That is, the detected value of the sensor TS1 is the temperature of the refrigerant before being cooled by the cooler 25. Further, the sensor TS2 arranged on the outlet side of the cooler 25 detects the temperature of the refrigerant at the position indicated as point T2 in the refrigeration cycle R1 of FIG. 5. That is, the detected value of the sensor TS2 is the temperature of the refrigerant immediately after being cooled and vaporized by the cooler 25.

[0040] The difference between the detection result of the sensor TS1 and the detection result of the sensor TS2 indicates the change amount of the refrigerant temperature before and after cooling by the cooler 25. In other words, the difference between the detection result of the sensor TS1 and the detection result of the sensor TS2 represents the heat exchange amount of the refrigerant in the cooler 25. The heat exchange amount is an index indicating how much heat energy has been exchanged by the cooler 25.

[0041] <Regarding the control method in the first embodiment> Hereinafter, the control method in the first embodiment will be described. FIG. 6 is a flowchart of the control executed in the first embodiment. The control device 80 executes the flowchart of FIG. 6, for example, triggered by the power-on of the refrigerator 10 or the reception of a cooling start command from the user.

[0042] The control device 80 drives the compressor 90 at the rotational speed N1 (step S101). The rotational speed N1 in step S101 is the normal rotational speed of the compressor 90. Hereinafter, the operation in which the compressor 90 rotates at the rotational speed N1 is referred to as "normal operation". The control device 80 acquires the inflow temperature from the sensor TS1 (step S102). That is, the control device 80 acquires the detection result of the sensor TS1 and specifies the temperature of the refrigerant flowing into the cooler 25 based on the detected surface temperature of the pipe. The control device 80 acquires the outflow temperature from the sensor TS2 (step S103). That is, the control device 80 acquires the detection result of the sensor TS2 and specifies the temperature of the refrigerant flowing out of the cooler 25 based on the detected surface temperature of the pipe.

[0043] Thereafter, the control device 80 determines whether or not the temperature difference ΔT between the inflow temperature and the outflow temperature is equal to or greater than the lower threshold value and equal to or less than the upper threshold value (step S104). That is, the control device 80 determines whether or not the temperature difference ΔT between the inflow temperature and the outflow temperature is a temperature within a specified range. The lower threshold value is a value smaller than the upper threshold value. Note that the upper threshold value may correspond to the "first threshold value" in the present disclosure. The lower threshold value may correspond to the "second threshold value" in the present disclosure.

[0044] As described above, the temperature difference ΔT between the inflow temperature and the outflow temperature represents the heat exchange amount in the cooler 25. When the temperature difference ΔT is within the specified range of equal to or greater than the lower threshold value and equal to or less than the upper threshold value (YES in step S104), the control device 80 determines that the heat exchange amount of the cooler 25 is within an appropriate range, and returns the process to step S101. That is, the control device 80 continues the normal operation.

[0045] On the other hand, when the temperature difference ΔT is not within the specified range (NO in step S104), the control device 80 determines whether or not the temperature difference ΔT exceeds the upper threshold value (step S105). When it exceeds the upper threshold value (YES in step S105), the control device 80 drives the compressor 90 at the rotational speed N2 (step S106). The rotational speed N2 is a rotational speed higher than the rotational speed N1. That is, the control device 80 increases the rotational speed of the compressor 90.

[0046] The state where the temperature difference ΔT exceeds the upper limit threshold value is a state where the amount of change from the inflow temperature to the outflow temperature is large. This state means that the heat exchange amount is larger compared to the state where the heat exchange amount of the cooler 25 is within an appropriate range. For example, based on the frequent opening and closing of the door, or the large number of foods to be cooled being put in all at once, etc., the air temperature in the cooling chamber 45 may become higher than the air temperature in the cooling chamber 45 during normal operation. Therefore, the cooling incapability increases, and the temperature difference ΔT exceeds the upper limit threshold value.

[0047] Based on the fact that the temperature difference ΔT has exceeded the upper limit threshold value, the control device 80 in Embodiment 1 increases the rotational speed of the compressor 90 and raises the cooling efficiency in order to reduce the temperature inside the storage more. Hereinafter, the operation of rotating the compressor 90 at the rotational speed N2 is referred to as the "recovery operation" as compared with the normal operation of rotating the compressor 90 at the rotational speed N1.

[0048] Subsequently, the control device 80 determines whether or not the temperature difference ΔT has reached below the upper limit threshold value (step S107). If the temperature difference ΔT has not reached below the upper limit threshold value (NO in step S107), the control device 80 repeats the process of step S107 and continues the recovery operation. When the temperature difference ΔT has reached below the upper limit threshold value (YES in step S107), the control device 80 determines that the heat exchange amount has returned to the appropriate range by the recovery operation, and returns the process to step S101. That is, the control device 80 switches from the recovery operation to the normal operation.

[0049] On the other hand, in step S105, when the temperature difference ΔT does not exceed the upper limit threshold value (NO in step S105), the control device 80 stops the compressor 90 (step S108). In step S105, the case where the temperature difference ΔT does not exceed the upper limit threshold value means that the temperature difference ΔT is less than the lower limit threshold value. The state where the temperature difference ΔT is less than the lower limit threshold value is a state where the amount of change from the inflow temperature to the outflow temperature is small. This means that the heat exchange amount is smaller compared to the case where the heat exchange amount of the cooler 25 is within an appropriate range.

[0050] When frost adheres to the cooler 25, the heat exchange between the refrigerant in the cooler 25 and the air in the cooling chamber 45 is obstructed by the frost. Therefore, the amount of heat exchange by the cooler 25 becomes small. Since the control device 80 of the first embodiment determines that frost adheres to the cooler 25 because the amount of heat exchange by the cooler 25 is small. The control device 80 executes a process for removing the frost adhering to the cooler 25 in steps S108 to S115. Hereinafter, the processes of steps S108 to S115 are referred to as "defrost operation".

[0051] Subsequently, the control device 80 drives the indoor fan 15 (step S109). The sublimation of the frost adhering to the cooler 25 is promoted by the blowing of the indoor fan 15. The control device 80 determines whether or not a specified period has elapsed (step S110). If the specified period has not elapsed (NO in step S110), the control device 80 repeats the process of step S110. That is, the control device 80 drives the indoor fan 15 with the compressor 90 stopped for a specified period.

[0052] If the specified period has elapsed (YES in step S110), the control device 80 drives the compressor 90 at the rotational speed N1 (step S111). Subsequently, after step S111 ends, the control device 80 waits for a predetermined period. Thereafter, the control device 80 determines whether or not the temperature difference ΔT is equal to or greater than the lower threshold value (step S112). If the temperature difference ΔT is equal to or greater than the lower threshold value (YES in step S112), the control device 80 determines that the frost adhering to the cooler 25 has been removed and returns the process to step S101. That is, it switches from the state where the compressor 90 is stopped to normal operation.

[0053] When the temperature difference ΔT is not equal to or greater than the lower threshold value (NO in step S112), the control device 80 determines that the frost adhering to the cooler 25 has not yet been removed, and stops the indoor fan 15 and the compressor 90 (step S113). Thereafter, the control device 80 drives the heater 35 (step S114). The control device 80 determines whether or not a specified period has elapsed (step S115). If the specified period has not elapsed (NO in step S115), the control device 80 repeats the process of step S115. That is, the control device 80 continues to drive the heater 35. In this way, by driving the heater 35 over the specified period, the frost adhering to the cooler 25 melts.

[0054] Based on the fact that the specified period has elapsed in step S115 (YES in step S115), the control device 80 switches the state of the refrigerator 10 back to normal operation again. Note that the specified period in step S110 and the specified period in step S115 may be the same period or different periods.

[0055] As described above, in the refrigerator 10 of the first embodiment, based on the temperature difference ΔT of the refrigerant at the inlet and outlet of the cooler 25, the heat exchange amount of the cooler 25 is estimated, and the process to be executed is changed according to the estimated heat exchange amount. That is, the control device 80 controls the compressor 90 and the heater 35 based on the temperature difference between the inflow temperature and the outflow temperature and at least one threshold value.

[0056] More specifically, when the heat exchange amount by the cooler 25 is greater than an appropriate heat exchange amount determined in advance, the control device 80 determines that the load in the compartment is large, and increases the rotational speed of the compressor 90. Further, when the heat exchange amount by the cooler 25 is smaller than the appropriate heat exchange amount determined in advance, the control device 80 determines that frost is adhering to the cooler 25, and performs a defrosting operation. Thereby, in the refrigerator 10 of the first embodiment, it is possible to determine whether or not frost is adhering to the cooler 25 based on the difference in the refrigerant temperature at the inlet and outlet of the cooler 25, and to perform the driving of the compressor 90 and the defrosting operation at appropriate timings.

[0057] Embodiment 2 In Embodiment 1, the configuration in which sensors TS1 and TS2, which are thermistors, are arranged in the pipes near the inlet and outlet of the cooler 25 was described. In Embodiment 2, a configuration in which the arrangement of the sensor TS2 is changed will be described.

[0058] FIG. 7 is a diagram for explaining the arrangement of the sensors TS1 and TS2 in Embodiment 2. In FIG. 7, the description of the configuration overlapping with the refrigerator 10 in FIG. 1 will not be repeated. As described above, a foam heat insulating material 22 (not shown) is arranged around the pipe connecting the accumulator 49 and the machine room 95. The sensor TS2 in Embodiment 2 is arranged in the pipe connecting the accumulator 49 and the machine room 95. More specifically, it is connected to the pipe at a position immediately before being connected to the machine room 95.

[0059] FIG. 8 is a P-h diagram in Embodiment 2. In the P-h diagram in FIG. 8, a refrigeration cycle R1 showing the state transition of the refrigerant in the present embodiment is shown, similar to FIG. 5. In Embodiment 2, the sensor TS2 is arranged between the machine room 95 and the accumulator 49. The control device 80 detects the temperature of the refrigerant at the position indicated as point T2A in the refrigeration cycle R1 in FIG. 8 based on the detection value of the sensor TS2. The refrigerant temperature at the position indicated as point T2A is the temperature of the refrigerant immediately before being sucked into the compressor 90.

[0060] Hereinafter, the temperature of the refrigerant immediately before being sucked into the compressor 90 will be simply referred to as the "pre-compression temperature". The pre-compression temperature in Embodiment 2 is included in the "outflow temperature". However, the pre-compression temperature in Embodiment 2 is the temperature of the refrigerant closer to the suction side of the compressor 90 than the outflow temperature in Embodiment 1.

[0061] Accordingly, in Embodiment 2, instead of the outlet temperature, the temperature before compression is used to execute the flowchart shown in FIG. 6. That is, the control device 80 in Embodiment 2 controls the compressor 90 and the heater 35 based on the difference between the inlet temperature and the temperature before compression. If the temperature before compression can be detected, the heat exchange amount by the cooler 25 can be determined using so-called superheat. Superheat is the temperature difference from point T2 to point T2A. That is, in Embodiment 2, it is possible to determine the heat exchange amount by the cooler 25 in consideration of the suction density of the refrigerant with respect to the compressor 90.

[0062] When the amount of frost adhering to the cooler 25 is large, heat exchange is hindered, the superheat becomes small, and the suction density of the refrigerant into the compressor 90 increases. When the suction density of the refrigerant increases, the temperature of the refrigerant increases. Therefore, the temperature before compression in Embodiment 2 rises earlier than the outlet temperature in Embodiment 1 based on the frosting state. Therefore, in Embodiment 2, it is possible to shift to the defrost operation earlier than in Embodiment 1 from the normal operation. Also, in Embodiment 2 as well, based on the difference in the refrigerant temperature between the inlet and outlet of the cooler 25, it is possible to determine whether or not frost is adhering to the cooler 25, and to drive the compressor 90 and perform the defrost operation at an appropriate timing.

[0063] Embodiment 3. In Embodiments 1 and 2, an example where the sensor TS1 is a thermistor has been described. However, the sensor TS1 is not limited to a temperature sensor such as a thermistor. In Embodiment 3, an example where the sensor TS1 is a sensor that measures the pressure of the refrigerant in the pipe will be described.

[0064] In the examples of Embodiments 1 and 2, it has been described that the control device 80 estimates the temperature of the refrigerant in the pipe based on the temperature of the sensor TS1 disposed in the pipe. As shown in FIGS. 5 and 8, if the control device 80 can acquire the pressure of the refrigerant, the temperature of the refrigerant can be specified using the P-h diagram. The sensor TS1 in Embodiment 3 is a pressure sensor that detects the pressure of the refrigerant in the pipe.

[0065] Also in Embodiment 3, the sensor TS1 which is a pressure sensor is arranged at the position described in Embodiments 1 and 2. The control device 80 specifies the refrigerant temperature near the inlet of the cooler 25 by using the pressure of the refrigerant detected by the sensor TS1 which is a pressure sensor and the P-h diagram. Thereby, also in Embodiment 3, the control device 80 can specify the inflow temperature by using the pressure sensor. The control device 80 controls the compressor 90 and the heater 35 based on the difference between the inflow temperature and the outflow temperature specified by using the pressure sensor.

[0066] When a thermistor is arranged in the pipe, since the thermistor is affected by the air in the cooling chamber 45, variations may occur in the detection results. On the other hand, when estimating the temperature of the refrigerant from the pressure, since it is not affected by the air in the cooling chamber 45, in Embodiment 3, the temperature of the refrigerant can be estimated with higher accuracy. Also in Embodiment 3, based on the difference in the refrigerant temperature between the inlet and the outlet of the cooler 25, it is possible to determine whether frost is adhering to the cooler 25 and perform the driving of the compressor 90 and the defrosting operation at appropriate timings.

[0067] [Modification Example] In the example of Embodiment 1, an example was described in which when the temperature difference ΔT is less than the lower threshold value (NO in step S105), the compressor 90 is stopped (step S108) and the indoor fan 15 is driven over a specified period (steps S109, S110). However, in some aspects, it is not necessary to execute the processes of steps S108 to S112. That is, the heater driving (step S114) may be executed without executing only the driving process of the indoor fan 15 that promotes the sublimation of frost.

[0068] Also, in the example of Embodiment 1, in the process of step S106, an example of increasing the rotation speed of the compressor 90 was described. However, the process in the process of step S106 is not limited to increasing the rotation speed of the compressor 90. For example, in the process of step S106, the rotation speed of the compressor 90 may be gradually increased. Further, when the refrigerator 10 is configured to increase the rotation speed of the compressor 90 based on a predetermined condition, the content of the predetermined condition may be relaxed.

[0069] Furthermore, in the example of Embodiment 1, an example of determining that the cooler 25 is in a frosting state when the temperature difference ΔT of the refrigerant at the inlet and outlet of the cooler 25 is smaller than the lower threshold value was described. However, the factor that the temperature difference ΔT becomes smaller than the lower threshold value is not limited to only the frosting state of the cooler 25, and it is conceivable that foreign matter accumulates in the air passage or the air passage freezes. Therefore, in a certain situation, after driving the heater 35 and then switching to the normal operation (YES in step S115), if the temperature difference ΔT becomes smaller than the lower threshold value again within a predetermined period, the control device 80 notifies the user that some abnormality has occurred in the refrigerator 10. This predetermined period can be, for example, a period of 1 minute, 3 minutes, 5 minutes, etc.

[0070] In Embodiment 3, it was described that the sensor TS1 may be a pressure sensor. Regarding the refrigerant temperature on the outlet side of the cooler 25, when the temperature of the refrigerant can be detected based on the pressure of the refrigerant or the like, the sensor TS2 may also be a pressure sensor for the refrigerant.

[0071] (Summary) The following summarizes this embodiment.

[0072] (Item 1) A refrigerator according to an aspect includes a compressor, a cooler, a cooling chamber in which the cooler is disposed, a first sensor that detects an inflow temperature of a refrigerant flowing into the cooler, a second sensor that detects an outflow temperature of the refrigerant flowing out of the cooler, a heater that removes frost adhering to the cooler, a control device that controls the compressor and the heater, and a fan disposed in the cooling chamber. The control device acquires the detection result of the first sensor, acquires the detection result of the second sensor, and controls the compressor and the heater based on a temperature difference between the inflow temperature and the outflow temperature and at least one threshold value.

[0073] According to this, in a refrigerator that detects the refrigerant temperatures at the inlet and outlet of the cooler, it is possible to determine whether or not frost is adhering to the cooler, and to drive the compressor and perform a defrosting operation at an appropriate timing.

[0074] (Item 2) In Item 1, when the temperature difference between the inflow temperature and the outflow temperature exceeds a first threshold value, the control device increases the rotation speed of the compressor, and when the temperature difference is less than a second threshold value that is smaller than the first threshold value, the control device drives the heater.

[0075] (Item 3) In Item 2, when the temperature difference is less than the second threshold value, the control device drives the fan for a specified period.

[0076] (Item 4) In any one of Items 1 to 3, the first sensor includes a thermistor disposed in a pipe through which the refrigerant flowing into the cooler passes, and the second sensor includes a thermistor disposed in a pipe through which the refrigerant flowing out of the cooler passes.

[0077] (Item 5) In any one of Items 1 to 4, the region where the first sensor and the second sensor are disposed is a region different from the region between the cooler and the fan.

[0078] (Item 6) In Item 4 or Item 5, further includes an accumulator configured to accumulate the refrigerant and disposed between the cooler and the compressor, and the second sensor is disposed between the accumulator and the cooler.

[0079] (Item 7) In Item 4 or Item 5, further comprising a machinery room for housing a compressor and an accumulator configured to be able to accumulate refrigerant and disposed between the cooler and the compressor, and the second sensor is disposed between the accumulator and the machinery room.

[0080] (Item 8) In any one of Items 1 to 3, the first sensor includes a pressure sensor for detecting the pressure of the refrigerant flowing into the cooler, and the second sensor includes a thermistor for detecting the temperature of the pipe through which the refrigerant flowing out of the cooler passes.

[0081] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Description of Reference Numerals

[0082] 10S Outer box, 15 Interior fan, 20 Heat insulation box body, 21 Vacuum heat insulation material, 22 Foamed heat insulation material, 25 Cooler, 29 Switching device, 30L, 30S Capillary tube, 35 Heater, 45 Cooling chamber, 49 Accumulator, 50a, 50f Partition member, 65 Control room, 80 Control device, 85 Condenser, 90 Compressor, 95 Machinery room, 100 Refrigerator body, Ch Child room, F Freezer room, Fd, Id, Rd, Rd2, Sd, Vd Damper device, Ft, It, Qt, Rt, St, Vt Thermistor, I Ice making room, N1, N2 Rotation speed R Refrigerator room, R1 Refrigeration cycle, Rg1 Region, S Switching room, T1, T2A, T2 Points, TS1, TS2 Sensors, V Vegetable room.

Claims

1. A compressor, A cooler, A cooling chamber for arranging the cooler, A first sensor for detecting the inflow temperature of the refrigerant flowing into the cooler, A second sensor for detecting the outflow temperature of the refrigerant flowing out of the cooler, A heater for removing frost adhering to the cooler, A control device for controlling the compressor and the heater, And a fan arranged in the cooling chamber, The control device, Acquires the detection result of the first sensor, Acquires the detection result of the second sensor, And controls the compressor and the heater based on the temperature difference between the inflow temperature and the outflow temperature and at least one threshold value. A refrigerator.

2. The control device, When the temperature difference between the inflow temperature and the outflow temperature exceeds a first threshold value, increases the rotational speed of the compressor, When the temperature difference is less than a second threshold value smaller than the first threshold value, drives the heater. The refrigerator according to claim 1.

3. The control device drives the fan for a specified period when the temperature difference is less than the second threshold value. The refrigerator according to claim 2.

4. The first sensor includes a thermistor arranged in a pipe through which the refrigerant flowing into the cooler passes, The second sensor includes a thermistor arranged in a pipe through which the refrigerant flowing out of the cooler passes. The refrigerator according to any one of claims 1 to 3.

5. The region where the first sensor and the second sensor are arranged is a region different from the region between the cooler and the fan. The refrigerator according to any one of claims 1 to 3.

6. Further comprising an accumulator configured to accumulate refrigerant and disposed between the cooler and the compressor. The refrigerator according to claim 4, wherein the second sensor is disposed between the accumulator and the cooler.

7. A machine room for housing the compressor, Further comprising an accumulator configured to accumulate refrigerant and disposed between the cooler and the compressor. The refrigerator according to claim 4, wherein the second sensor is disposed between the accumulator and the machine room.

8. The first sensor includes a pressure sensor that detects the pressure of the refrigerant flowing into the cooler. The refrigerator according to any one of claims 1 to 3, wherein the second sensor includes a thermistor that detects the temperature of a pipe through which the refrigerant flowing out of the cooler passes.

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