Cooling warehouse

Abstract

To provide a cooling storage capable of suppressing overload operation of a compressor while suppressing increase in the manufacturing cost and the space.SOLUTION: A cooling storage 10 includes: a cooling storage body 11; a cooling device 12 having a compressor 27, a condenser 28, and an evaporator; a plurality of circulating fans 25 for circulating air in the cooling storage body 11; a temperature sensor 26 which can detect a condensation temperature of the condenser 28; and a control unit 60. Each of the circulating fans 25 can be individually driven at a constant speed. In cooling operation for cooling the inside of the cooling storage body 11, the control unit 60 operates the compressor 27 and the plurality of circulating fans 25, and stops at least one of the circulating fans 25 in operation when a detection temperature T26 of the temperature sensor 26 is equal to or higher than a first threshold temperature Tth1.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present technology relates to refrigerators. [Background technology]

[0002] It is known that compressors, which are part of a refrigeration cycle, can shorten their lifespan and produce abnormal noises when overloaded. For this reason, technologies have been proposed to avoid compressor overload operation, one example of which is disclosed in Patent Document 1. Patent Document 1 discloses a technology for avoiding compressor overload operation in a refrigeration cycle installed in a vending machine by adjusting the rotation speed of a blower fan attached to the evaporator (cooler) or by changing the rotation speed of the compressor to adjust the amount of refrigerant circulating. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-184019 Summary of the Invention [Problem to be solved by the invention]

[0004] One type of equipment that utilizes a refrigeration cycle is a rapid cooling cabinet, which rapidly cools high-temperature foods in a short period of time. In recent years, the use of rapid cooling cabinets has expanded, and demand for them is also increasing in small stores. Small stores require space-saving, inexpensive products, but it is difficult to achieve both miniaturization and avoidance of compressor overload. For example, adjusting the rotation speed of the blower fan or compressor to avoid compressor overload by applying the technology described in Patent Document 1 requires an inverter circuit or the like, which increases installation space and manufacturing costs. Furthermore, there are currently no small-sized blower fans available that can adjust their rotation speed while ensuring the required airflow for rapid cooling.

[0005] The technology described in this specification was developed based on the above-mentioned circumstances, and aims to realize a refrigerator that can suppress overload operation of the compressor while suppressing increases in manufacturing costs and space. [Means for solving the problem]

[0006] A refrigerator related to the technology described in the present specification comprises a cooling device having a refrigerator main body, a compressor that compresses a refrigerant, a condenser that liquefies the refrigerant compressed by the compressor, and an evaporator that vaporizes the refrigerant from the condenser to generate cold air, a plurality of circulation fans that circulate air within the refrigerator main body, a temperature sensor that can detect the condensation temperature of the condenser, and a control unit, wherein each of the plurality of circulation fans can be operated individually at a constant speed, and the control unit operates the compressor and the plurality of circulation fans during cooling operation to cool the interior of the refrigerator main body, and stops at least one of the plurality of operating circulation fans when the temperature detected by the temperature sensor is equal to or higher than a first threshold temperature.

[0007] The condensing temperature of the condenser is monitored by a temperature sensor. When the temperature detected by the temperature sensor exceeds a first threshold temperature, the system determines that the refrigerant temperature (refrigerant pressure) in the compressor is high and the compressor is operating under overload. The system then reduces the number of operating circulation fans to reduce the amount of air circulating within the refrigerator body. This reduces the amount of heat exchange (heat absorption) in the evaporator, allowing refrigerant with reduced pressure and temperature to be returned to the compressor, thereby preventing compressor overload. Furthermore, reducing the amount of air circulating within the refrigerator body can be achieved by simply stopping one of the circulation fans; there is no need to reduce the circulation fan's rotation speed. There is no need to install an inverter circuit or other device to vary the circulation fan's rotation speed, which avoids increases in cost and space.

[0008] Furthermore, when the temperature detected by the temperature sensor remains equal to or higher than the first threshold temperature for a predetermined period of time during the cooling operation, the control unit stops the compressor. By stopping the compressor, overload operation of the compressor can be more reliably prevented and the compressor can be protected.

[0009] Furthermore, when the temperature detected by the temperature sensor is equal to or higher than a second threshold temperature that is higher than the first threshold temperature during the cooling operation, the control unit stops the compressor. By stopping the compressor, overload operation of the compressor can be more reliably suppressed and the compressor can be protected.

[0010] The condenser is a microchannel heat exchanger that exchanges heat with air passing through it. The condenser includes a condenser fan for cooling the microchannel heat exchanger, an air filter installed on the air inlet side of the microchannel heat exchanger, and an installation sensor for detecting the presence or absence of the air filter. When the installation sensor detects that the air filter is not installed, the control unit does not operate the compressor, the condenser fan, and the multiple circulation fans. While using a microchannel heat exchanger as a condenser allows for a compact design, it is prone to clogging due to the adhesion of foreign matter such as dust and oily smoke. Therefore, when the installation sensor detects that an air filter is not installed, the control unit does not operate each device related to operation (does not operate). This allows for a compact condenser while preventing clogging.

[0011] The control unit may also include a notification unit capable of issuing a warning when the installation sensor detects that the air filter is not installed, and the control unit may issue a warning through the notification unit. In this way, it is possible to warn that the air filter has been left installed.

[0012] The temperature sensor is a condenser temperature sensor provided in a refrigerant pipe on the refrigerant outlet side of the condenser, so that the condensing temperature of the condenser can be easily detected by the condenser temperature sensor. [Effects of the Invention]

[0013] According to the technology described in this specification, it is possible to realize a refrigerator that can suppress overload operation of the compressor while suppressing increases in manufacturing costs and space. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view of a refrigerator according to a first embodiment; [Figure 2] Perspective view of the refrigerator with the door open [Figure 3] Cross section of line AA in Figure 1 [Figure 4] Left side view of the refrigerator [Figure 5] Cross section of line BB in Figure 4 [Figure 6] Cross section of line CC in Figure 4 [Figure 7] Schematic diagram of the refrigeration cycle [Figure 8] Enlarged view of the upper part of the door in Figure 4 [Figure 9] A perspective view of a microchannel heat exchanger and a defrosting heater. [Figure 10] A plan view showing the structure of a microchannel heat exchanger. [Figure 11] A perspective view schematically showing flat refrigerant tubes of a microchannel heat exchanger. [Figure 12] Flowchart for controlling cooling operation DETAILED DESCRIPTION OF THE INVENTION

[0015] <Embodiment 1> A refrigerator 10 according to the first embodiment will be described with reference to Figures 1 to 12. Note that the symbols F, Rr, L, R, U, and D shown in the figures respectively indicate the front and rear in the front-to-rear direction of the refrigerator 10, the left and right in the width direction (left-right direction) when viewed from the front, and the top and bottom in the vertical direction (up-down direction). However, these directions are merely defined for convenience and should not be interpreted in a restrictive manner.

[0016] Refrigerator 10 is a rapid cooling chamber (a rough cooling machine, a blast chiller) that rapidly cools high-temperature food (an example of an object to be cooled) after cooking in a short period of time. Refrigerator 10 can rapidly cool (including freezing) food by passing through a temperature range where bacteria are likely to grow (e.g., +10°C to +60°C) and a temperature range where ice crystals grow when the water in the food freezes (e.g., -1°C to -5°C) in a short period of time. Refrigerator 10 is a small rapid cooling chamber that can be used in small stores, and its external dimensions are, for example, approximately 500 mm (horizontal) × 500 mm (front-to-back) × 510 mm (vertical). However, the technology described in this specification is not limited to small refrigerators 10, but can also be applied to medium- to large-sized refrigerators.

[0017] 1 to 6, refrigerator 10 has a generally rectangular parallelepiped shape overall and roughly comprises refrigerator body 11, a cooling device 12 for cooling storage chamber 14 formed within refrigerator body 11, a machine room 15 arranged above refrigerator body 11, and a heat-insulating door 13 for opening and closing first front opening 11S of refrigerator body 11. Refrigerator body 11 is an insulated box having first front opening 11S, and is composed of walls (more specifically, ceiling wall 11A, bottom wall 11B, left side wall 11C, right side wall 11D, and rear wall 11E) filled with a heat insulating material such as urethane foam.

[0018] As shown in Figures 2 and 3 and 5 and 6, a cooling case (fan cover) 17 is provided along the right side wall 11D inside the refrigerator main body 11 (hereinafter sometimes simply referred to as the inside of the refrigerator). Inside the cooling case 17, an evaporator 23 constituting part of the cooling device 12 and a plurality of (two in this embodiment) evaporator fans 25 (an example of a circulation fan) are housed and lined up in this order from the right side wall 11D side, and a defrosting heater 24 that melts frost adhering to the evaporator 23 is provided between the evaporator 23 and the right side wall 11D. The defrosting heater 24 also serves as a heating means for raising the temperature inside the refrigerator.

[0019] The evaporator 23 is a so-called microchannel heat exchanger, the configuration of which will be described in detail later. The defrosting heater 24 is a sheathed heater provided in a serpentine shape along one side (right side) of the evaporator 23 (FIG. 9). The defrosting heater 24 may be formed of a material other than a sheathed heater as long as it can perform a heating function. The evaporator fans 25 are equipped with waterproof, constant-speed DC motors. The DC motors of each evaporator fan 25 are connected to a relay circuit on the control board 62A, which will be described later, and can be driven individually.

[0020] As shown in Figures 5 and 6, a rear duct 20 is provided on the rear wall 11E of the refrigerator body 11. The right end of the rear duct 20 is connected to the rear end of the cooling case 17, and the inside of the rear duct 20 (the space surrounded by the rear wall 11E and the rear duct 20) serves as a flow path for returning air from the cooling case 17 to the storage chamber 14. A plurality of air outlets 20A are formed in the rear duct 20, and air that flows into the rear duct 20 is blown out from the air outlets 20A into the storage chamber 14. A drain outlet 11B1 is provided on the rear of the bottom wall 11B for draining water that is generated when the interior of the refrigerator is cleaned, and a drain hose 90 is connected to the drain outlet 11B1 for draining the water to the outside.

[0021] Within refrigerator body 11, the area surrounded by ceiling wall 11A, bottom wall 11B, left side wall 11C, cooling case 17, and rear duct 20 forms storage chamber 14 for storing items to be cooled. As shown in Figure 6, left side wall 11C and cooling case 17 are provided with a multi-tiered tray support structure 16, and trays carrying food items are inserted into and removed from storage chamber 14 through first front opening 11S. The trays are supported by tray support structure 16 and can be stored in multiple rows vertically.

[0022] 3, a plurality of intake ports 17A1 are formed in the left wall portion 17A of the cooling case 17, on which the tray support structure 16 is provided. The plurality of intake ports 17A1 are provided at positions facing at least the evaporator fan 25, and when the evaporator fan 25 is activated, the air inside the accommodation chamber 14 is drawn into the cooling case 17 through the intake ports 17A1. The cooling case 17 also has an openable / closable structure, and by removing the fastener 17B, the cooling case 17 can be opened so that the accommodation portion for the evaporator fan 25 and the accommodation portion for the evaporator 23 are separated. Opening the cooling case 17 makes it easier to clean and dry the evaporator fan 25 and the evaporator 23.

[0023] According to the structure of the refrigerator body 11 described above, when the evaporator fan 25 is activated, the air inside the storage chamber 14 is drawn into the evaporator fan 25 through the intake port 17A1 of the cooling case 17, passes through the evaporator 23, and then flows into the rear duct 20, as shown by the arrows in FIG. 5 . The air inside the rear duct 20 then returns to the storage chamber 14 through the outlet port 20A. Such a circulation flow path is formed inside the refrigerator, and an internal temperature sensor 21 that detects the internal temperature is provided at a position where the air passing through this circulation flow path hits. In this embodiment, the internal temperature sensor 21 is provided inside the rear duct 20.

[0024] As shown in Figures 2 to 6, the machine room 15 is located on the ceiling wall 11A of the refrigerator body 11. The left, right, rear, and top of the machine room 15 are covered with a panel 15A having multiple air vents 15A1. By attaching a separate mounting member to the top surface of the panel 15A, other equipment such as an oven cooker can be placed on it, improving convenience for use in small stores. As shown in Figure 4, a second front opening 15S is provided on the front of the machine room 15, and a horizontally elongated first electrical box (operation box) 61 is attached above the second front opening 15S. An air filter 18 is attached to the second front opening 15S to allow air to pass through while preventing foreign matter such as dust from entering the machine room 15 (more specifically, the condenser 28 described below). As shown in FIGS. 4 and 8, when the door 13 is closed, the front of the opening edge of the second front opening 15S is covered by the door 13 with a gap G1 therebetween.

[0025] As shown in Fig. 2, air filter 18 has a configuration in which a mesh-like sheet member 18B is attached to frame body 18A. Air filter 18 is detachably attached to the opening edge of second front opening 15S of machine room 15, so that a user can open door 13, remove air filter 18, and perform cleaning, etc. In addition, an attachment sensor 19 that detects the presence or absence of air filter 18 is provided at the opening edge of second front opening 15S. A sensor that performs electrical or mechanical detection, or a switch (for example, a reed switch or a microswitch) can be used as attachment sensor 19, and the type is not particularly limited.

[0026] As shown in FIGS. 1 and 2, door 13 is a swinging right-opening door that is large enough to cover the front of refrigerator body 11 and the lower front surface of machine room 15. Door 13 is swingably attached to the right side of the opening edge of first front opening 11S of refrigerator body 11 by hinge member 40. The portion of door 13 that covers the front surface of refrigerator body 11 is thermally insulated. Gasket 13A is provided on the surface (rear surface) of door 13 facing refrigerator body 11 so as to correspond to the opening edge of first front opening 11S. Door 13 can open and close first front opening 11S by having gasket 13A come into close contact with the opening edge of first front opening 11S. On the other hand, the portion of door 13 that covers the lower front surface of machine room 15 is not thermally insulated, and no gasket is provided in the portion that corresponds to the opening edge of second front opening 15S. The door 13 is closed without sealing the second front opening 15S, leaving a gap G1 between the door 13 and the opening edge of the second front opening 15S (FIG. 8). When the door 13 is closed, the second front opening 15S and the air filter 18 are covered from the front by the door 13 and cannot be seen from the front.

[0027] As shown in FIGS. 4 and 8 , a gap G1 is formed between the upper left and right sides of the door 13 when the door 13 is closed. This allows outside air to flow from the gap G1 into the machine chamber 15 through the second front opening 15S. That is, an intake air flow path is formed between the upper left and right sides of the door 13, allowing outside air to flow from the gap G1 to the second front opening 15S. The intake air flow path allows outside air to flow into the machine chamber 15 even when the door 13 is closed, which increases the amount of air flowing into the condenser 28 in the machine chamber 15. This allows the condenser 28 to be efficiently air-cooled, lowering the condensation temperature of the refrigerant in the condenser 28 and reducing the load on the compressor 27. Furthermore, reducing the load on the compressor 27 reduces the power consumption required to operate the compressor 27. Furthermore, condensation formed on the top of the packing 13A of the door 13 due to the outside air passing through the intake air flow path can be suppressed.

[0028] As shown in FIGS. 2 to 6 , the machinery compartment 15 accommodates the machinery (compressor 27, condenser 28, condenser fan 29, etc.) that constitutes the cooling device 12, a first electrical box 61, and a second electrical box 62. The first electrical box 61 is attached to the upper front side of the machinery compartment 15 and has a horizontally long box shape. The left-right length of the first electrical box 61 is approximately the same as the left-right length of the door 13, and the bottom surface of the first electrical box 61 covers the entire upper surface of the door 13 from above. The front surface of the first electrical box 61 protrudes forward relative to the opening edge of the second front opening 15S of the machinery compartment 15 and the air filter 18, and the protruding length is such that it is approximately flush with the front surface of the door 13 when the door 13 is closed ( FIG. 8 ).

[0029] As shown in FIGS. 1 to 3 , the first electrical box 61 houses a display unit 61A that displays information, an operation unit 61B having various operation buttons, and an operation board 61C. The display unit 61A and the operation unit 61B are provided on the front surface of the first electrical box 61. The display unit 61A displays the current operation mode and various messages. The display unit 61A also functions as an alarm unit. For example, if the air filter 18 is not installed, a warning (including an error message) is displayed on the display unit 61A to notify the user of the forgetting to install the filter. Note that the display unit 61A is merely one example of an alarm unit, and the alarm unit may be a sound generating device such as a buzzer or a combination thereof. The user can operate the operation unit 61B to select the operation mode (cooling operation, drying operation, etc.) of the refrigerator 10 and issue an instruction to start operation. The display unit 61A and the operation unit 61B are connected to a control board 62A of the second electrical box 62 (described later) via the operation board 61C. The display unit 61A and the operation unit 61B may be integrally provided as a display device having a touch panel function.

[0030] As shown in Figures 3 and 6, the second electrical box 62 is provided on the rear right side of the first electrical box 61. The second electrical box 62 houses a control board 62A that includes circuits for controlling the operation of the refrigerator 10 and supplying power, a memory unit, etc. The control board 62A is electrically connected to an operation board 61C in the first electrical box 61, and the control board 62A and the operation board 61C form a control unit 60 that controls various devices in the refrigerator 10. The control unit 60 executes a control program recorded in the memory unit and controls the compressor 27, condenser fan 29, evaporator fan 25, defrost heater 24, etc. based on the detection results of each sensor and the operation of the operation unit 61B, thereby operating the refrigerator 10.

[0031] 7, the cooling device 12 includes a compressor 27, a condenser 28, a condenser fan 29, a dryer 30, an expansion valve (internal equalizing type) 31, and an evaporator 23. The compressor 27, the condenser 28, the dryer 30, the expansion valve 31, and the evaporator 23 are connected by a refrigerant pipe 12A, and the refrigerant is circulated in a predetermined direction to form a known refrigeration cycle. The cooling device 12 also includes a pressure-equalizing solenoid valve 32 in parallel with the compressor 27.

[0032] The compressor 27 is a constant-speed compressor equipped with a constant-speed motor. The compressor 27 uses the motor as a power source to draw in and compress refrigerant gas and discharge the high-temperature, high-pressure refrigerant gas. A constant-speed compressor does not require components (such as an inverter circuit) to vary the rotation speed of the motor, and is therefore smaller and less expensive than a variable-speed inverter compressor. The condenser 28 cools and liquefies the refrigerant gas compressed by the compressor 27 using air blown by a condenser fan 29. The condenser 28 is inclined and disposed behind the second front opening 15S and the air filter 18 of the machine room 15 (FIG. 3). The evaporator 23 reduces the pressure of the refrigerant liquid from the condenser 28 using an expansion valve 31 and then vaporizes it, thereby cooling the air passing through the evaporator 23 through heat exchange. The refrigerant gas from the evaporator 23 is returned to the compressor 27.

[0033] As shown in FIG. 3, the condenser fan 29 is installed upright behind the condenser 28. When the condenser fan 29 is activated, outside air flows in from the second front opening 15S and passes through the condenser 28 from front to back, air-cooling the condenser 28. The refrigerant passing through the condenser 28 is a high-temperature gas near the inlet on the compressor 27 side, and as it progresses through the condenser 28, it cools and its temperature decreases. When the temperature of the refrigerant gas drops to a saturation temperature (condensation temperature) corresponding to the pressure, it begins to condense into a liquid. The liquefaction rate of the refrigerant gas increases as it progresses through the condenser 28, and it becomes almost a refrigerant liquid near the outlet on the dryer 30 side. The dryer 30 removes moisture that has become mixed in the refrigerant.

[0034] As shown in FIGS. 4 and 7 , a condenser temperature sensor 26 (specifically, a temperature thermistor) is attached to the refrigerant outlet side of the condenser 28 in a manner housed in a thermistor holder. At the refrigerant outlet side of the condenser 28, most of the refrigerant is condensed and liquefied, and its temperature matches the condensation temperature. Therefore, the condenser temperature sensor 26 detects the condensation temperature of the refrigerant. Furthermore, because the condensation temperature of the refrigerant changes depending on the refrigerant pressure, the condenser temperature sensor 26 can indirectly detect the refrigerant pressure. Furthermore, if the condensation temperature (refrigerant pressure) of the refrigerant in the condenser 28 is high, it can be said that the refrigerant temperature (refrigerant pressure) in the compressor 27, which flows the refrigerant into the condenser 28, is also high. Therefore, by monitoring the temperature T26 detected by the condenser temperature sensor 26, it is possible to determine whether the refrigerant temperature (refrigerant pressure) in the compressor 27 is high and, ultimately, whether the compressor 27 is operating under overload.

[0035] The condenser 28 and the evaporator 23 are both microchannel heat exchangers with the same basic structure. Therefore, the following description of the structure of a microchannel heat exchanger will be given using the evaporator 23 as an example. As shown in FIGS. 9 to 11 , the evaporator 23 includes hollow cylindrical first and second head tubes 23A and 23B connected to the refrigerant tubes 12A, a plurality of flat refrigerant tubes 23C connecting the two head tubes 23A and 23B, and numerous fins 23D provided between the flat refrigerant tubes 23C. The first head tube 23A is connected to the refrigerant tube 12A on the refrigerant inlet side (expansion valve 31 side), and the refrigerant flows in from the refrigerant tube 12A. The second head tube 23B is connected to the refrigerant tube 12A on the refrigerant outlet side (compressor 27 side), and the refrigerant flows out to the refrigerant tube 12A. The flat refrigerant tubes 23C have a plurality of channels 23C1, which are minute internal cavities. The maximum inner diameter of each channel 23C1 is small, for example, about 1 mm to 2 mm. Each channel 23C1 serves as a refrigerant flow path through which the refrigerant flowing in from the first head tube 23A passes before flowing out to the second head tube 23B. The fins 23D are thin plates arranged in a bellows shape (triangular wave shape) between adjacent flat refrigerant tubes 23C. The fins 23D are joined to the outer surfaces of the flat refrigerant tubes 23C, and the fins 23D increase the surface area, thereby improving heat exchange capacity.

[0036] Using microchannel heat exchangers for the condenser 28 and the evaporator 23 allows for their miniaturization. For example, the thickness (lateral length) of the evaporator 23 according to this embodiment is approximately 30 mm, which is thinner than the approximately 55 mm thickness of a fin-and-tube heat exchanger (a heat exchanger having multiple flat fins and a single refrigerant tube that snakes through the multiple fins) with equivalent heat exchange capacity. However, because the spacing between the fins 23D (fin pitch L23D) of a microchannel heat exchanger is small, its use in the condenser 28 makes it prone to clogging due to the adhesion of foreign matter such as dust and oily smoke. Therefore, in this embodiment, if the attachment sensor 19 detects that the air filter 18 is not attached, the control unit 60, as described below, controls the refrigerator 10 not to operate. This allows for the condenser 28 to be miniaturized while preventing clogging due to the air filter 18 and reducing the frequency of maintenance work by a maintenance technician.

[0037] Furthermore, when a microchannel heat exchanger is used for the evaporator 23, clogging due to frosting is likely to occur due to the small fin pitch. Furthermore, defrost water generated from frost melted during defrosting operation is likely to remain, raising the concern that the defrost water may refreeze and cause further clogging. Therefore, in this embodiment, the control unit 60 executes a drying operation to dry the remaining defrost water after the defrosting operation. This makes it possible to reduce the size of the evaporator 23, while suppressing clogging due to frost and reducing the frequency of maintenance by a maintenance technician.

[0038] Next, the operation of the refrigerator 10 will be described in detail. The operation modes of the refrigerator 10 are roughly divided into cooling operation (rapid cooling operation), defrosting operation, and drying operation, and each operation mode will be described below. If the attachment sensor 19 detects that the air filter 18 is not attached, the control unit 60 will not start each operation and will display a warning on the display unit 61A. This makes it easier to prevent clogging of the condenser 28, even when a microchannel heat exchanger is used for the condenser 28 as in this embodiment. Note that "not starting operation" means "not operating equipment that should be operated during operation."

[0039] The cooling operation is an operating mode for rapidly cooling hot cooked food. The cooling operation is initiated by the user placing a tray containing food in the storage compartment 14 and then operating the operating unit 61B to initiate the cooling operation. During the cooling operation, the control unit 60 activates the compressor 27, condenser fan 29, and evaporator fan 25 of the cooling device 12. As shown by the arrows in FIG. 5 , the air inside the storage compartment 14 is drawn into the evaporator fan 25 through the air inlet 17A1 and cooled as it passes through the evaporator 23. The cooled air from the evaporator 23 passes through the rear duct 20 and is blown into the storage compartment 14 through the air outlet 20A. The blown air travels forward, passing between the trays and then being drawn into the air inlet 17A1 of the cooling case 17. This allows the cooled air to circulate within the storage compartment, rapidly cooling the food. The air inside the storage compartment also circulates along the same circulation path during the drying operation described below.

[0040] During the cooling operation of the refrigerator 10, high-temperature food is rapidly cooled, which tends to place a heavy load on the compressor 27. Therefore, in this embodiment, the control unit 60 performs control to prevent the compressor 27 from operating under overload during the cooling operation. This control will be described with reference to the flowchart in FIG. 12. When the cooling operation is started, the control unit 60 activates the two evaporator fans 25, the condenser fan 29, and the compressor 27 (S10, S12, S14). The control unit 60 also reads the temperature T26 detected by the condenser temperature sensor 26 and compares it with a predetermined first threshold temperature Tth1 (e.g., +54°C) (S16). If the detected temperature T26 is equal to or higher than the first threshold temperature Tth1 (YES in S16), the refrigerant temperature (refrigerant pressure) in the compressor 27 is high, as described above, and there is a concern that the compressor 27 may be operating under overload (overheating). Therefore, the control unit 60 stops one of the two evaporator fans 25 (S18).

[0041] When one evaporator fan 25 is stopped, the amount of warm air drawn from the accommodation chamber 14 into the evaporator 23 decreases, and the amount of heat exchanged (amount of heat absorbed) in the evaporator 23 can be reduced, thereby reducing the pressure of the refrigerant gas vaporizing in the evaporator 23 (refrigerant pressure at the outlet side). As a result, the refrigerant with reduced pressure and temperature can be returned to the compressor 27, preventing overload operation of the compressor 27. Furthermore, when reducing the airflow rate of the evaporator fan 25, as shown in step S18 of FIG. 12 , it is sufficient to stop one evaporator fan 25 to reduce the number of operating fans, and there is no need to reduce the rotational speed of the evaporator fan 25. Therefore, there is no need to provide an inverter circuit or the like to vary the rotational speed of the evaporator fan 25, and overload operation of the compressor 27 can be prevented without increasing costs and space.

[0042] Furthermore, if the load on the compressor 27 further increases, the control unit 60 stops the compressor 27 itself. More specifically, if the detected temperature T26 of the condenser temperature sensor 26 remains equal to or higher than the first threshold temperature Tth1 for a predetermined time (e.g., five minutes) (YES in S20), the control unit 60 stops the compressor 27 (S22). The compressor 27 generally has a specified upper limit for the refrigerant pressure (pressure operating range) to prevent components from being overloaded and damaged. If the pressure exceeds this upper limit, there is a risk that the life of the compressor 27 will be shortened or the compressor 27 will stop automatically and unexpectedly. Therefore, in this embodiment, if the detected temperature T26 of the condenser temperature sensor 26 remains equal to or higher than the first threshold temperature Tth1 for a predetermined time (YES in S20), the control unit 60 determines that the load on the compressor 27 is large and that there is a risk that the pressure will exceed the upper limit, and stops the compressor 27 (S22). This prevents the compressor 27 from being overloaded when the pressure exceeds the allowable upper limit, thereby protecting the compressor 27. When the temperature T26 detected by the condenser temperature sensor 26 falls below the first threshold temperature Tth1 (NO in S24), the control unit 60 operates the compressor 27 again (S14). This allows the cooling operation to continue while protecting the compressor 27.

[0043] In the above-described control, to determine whether the compressor 27 is in an overload state, the first determination condition is set to determine whether the temperature T26 detected by the condenser temperature sensor 26 is equal to or greater than the first threshold temperature Tth1 (S16), and the second determination condition is set to determine whether the state in which the temperature T26 detected by the condenser temperature sensor 26 is equal to or greater than the first threshold temperature Tth1 continues for a predetermined time (S20). However, the second determination condition may be any condition other than the condition in step S20 described above, as long as it is a condition that can determine whether the load on the compressor 27 is greater than the first determination condition. For example, the second determination condition may be set to determine whether the temperature T26 detected by the condenser temperature sensor 26 is equal to or greater than a second threshold temperature Tth2 (e.g., +60°C) that is greater than the first threshold temperature Tth1, and the compressor 27 may be stopped if the detected temperature T26 is equal to or greater than the second threshold temperature Tth2 (S22).

[0044] The defrosting operation is an operation mode for defrosting the evaporator 23. The defrosting operation is performed as needed during the cooling operation, or is performed when the user operates the operation unit 61B to instruct the start of the defrosting operation. In the defrosting operation, the control unit 60 stops the compressor 27 and the condenser fan 29 of the cooling device 12, and operates the evaporator fan 25 and the defrost heater 24. In the defrosting operation, the cooling device 12 is stopped and the defrost heater 24 is operated, thereby heating the evaporator 23. This allows the frost adhering to the evaporator 23 to melt.

[0045] Drying operation is an operation mode for drying the interior of the refrigerator. Drying operation is performed after defrosting operation, or when the user operates operation unit 61B to issue a command to start drying operation. Prior to starting drying operation, the user slightly opens door 13 to allow air inside and outside the refrigerator to be exchanged. In drying operation, control unit 60 operates evaporator fan 25, defrost heater 24, and condenser fan 29 without operating compressor 27. By circulating the air inside the refrigerator while raising and maintaining the temperature inside the refrigerator to approximately +40°C to +60°C using defrost heater 24 and evaporator fan 25, while allowing air inside and outside the refrigerator to be exchanged, moisture remaining inside the refrigerator (e.g., washing water remaining in storage chamber 14 and defrost water remaining in evaporator 23) can be dried. As described above, the evaporator 23 according to this embodiment is a microchannel heat exchanger and is prone to clogging due to frost. However, by performing a drying operation after a defrosting operation, clogging of the evaporator 23 can be reliably suppressed.

[0046] <Other embodiments> The technology described in this specification is not limited to the embodiments described above and in the drawings, and for example, the following embodiments are also included in the technical scope of the technology described in this specification.

[0047] (1) The number of evaporator fans 25 is not limited to two and may be three or more. In this case, in step S18 of FIG. 12 , the control unit 60 stops at least one of the three or more evaporator fans 25, thereby reducing the amount of air drawn into the evaporator 23 from the accommodation chamber 14.

[0048] (2) The circulation fan may be any fan other than the evaporator fan 25 installed adjacent to the evaporator 23 as long as it can circulate the air inside the refrigerator.

[0049] (3) During the defrosting operation and the drying operation, the control unit 60 may operate the evaporator fan 25 intermittently by repeatedly turning it on and off.

[0050] (4) During defrosting and drying operations, the control unit 60 may adjust the operation rate (power supply rate) of the defrost heater 24, or may perform defrosting and drying by blowing air from the evaporator fan 25 without operating the defrost heater 24.

[0051] (5) The heating means for the interior of the refrigerator may be something other than the defrosting heater 24, and may be, for example, a heater provided in the rear duct 20. [Explanation of symbols]

[0052] 10: Refrigerating cabinet, 11: Refrigerating cabinet body, 12: Cooling device, 12A: Refrigerant pipe, 18: Air filter, 19: Mounting sensor, 23: Evaporator, 25: Evaporator fan (circulation fan), 26: Condenser temperature sensor, 27: Compressor, 28: Condenser, 29: Condenser fan, 60: Control unit, 61A: Display unit (alert unit), T26: Detected temperature, Tth1: First threshold temperature, Tth2: Second threshold temperature

Claims

1. A refrigerator body, a cooling device including a compressor that compresses a refrigerant, a condenser that liquefies the refrigerant compressed by the compressor, and an evaporator that vaporizes the refrigerant from the condenser to generate cold air; A plurality of circulation fans that circulate air within the cooling cabinet body; a temperature sensor capable of detecting a condensation temperature of the condenser; a control unit, each of the plurality of circulation fans is independently operable at a constant speed; The control unit, in a cooling operation for cooling the inside of the refrigerator main body, activating the compressor and the plurality of circulation fans; When the temperature detected by the temperature sensor is equal to or higher than a first threshold temperature, at least one of the operating circulation fans is stopped; the condenser is a microchannel heat exchanger that exchanges heat with air passing through the condenser; a condenser fan for cooling the microchannel heat exchanger; an air filter provided on the air inlet side of the microchannel heat exchanger; an attachment sensor that detects the presence or absence of the air filter; The control unit of the refrigerator does not operate the compressor, the condenser fan, and the multiple circulation fans when the installation sensor detects that the air filter is not installed.

2. The refrigerator according to claim 1 , wherein the control unit stops the compressor when the temperature detected by the temperature sensor remains equal to or higher than the first threshold temperature for a predetermined period of time during the cooling operation.

3. The refrigerator according to claim 1 , wherein the control unit stops the compressor when the temperature detected by the temperature sensor is equal to or higher than a second threshold temperature that is higher than the first threshold temperature during the cooling operation.

4. a notification unit capable of issuing a warning; The refrigerator according to any one of claims 1 to 3, wherein the control unit issues a warning by the notification unit when the attachment sensor detects that the air filter is not provided.

5. 5. The refrigerator according to claim 1, wherein the temperature sensor is a condenser temperature sensor provided in a refrigerant pipe on a refrigerant outlet side of the condenser.

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