Cooling storage

Abstract

To provide a cooling storage capable of suppressing frosting of a cooler without using a defrosting heater.SOLUTION: A cooling storage includes: a storage chamber 11; a compressor 22; a cooler 26; a cooling chamber 25; a circulation fan 27 for circulating air between the storage chamber 11 and the cooling chamber 25; a temperature sensor 29 for measuring the temperature between the cooling chamber 25 and the storage chamber 11; a cooler temperature sensor 30 for measuring the temperature of the cooler 26; and a control part 40. The control part 40 executes a cooling operation for controlling the operation of the compressor 22 and the circulation fan 27 in such a manner that the measurement temperature of the storage chamber 11 measured by the temperature sensor 29 becomes a preset target setting temperature, and furthermore, during the cooling operation, in the case where the state continues for first predetermined time Y1 or longer where a measurement temperature T1 of the cooler 26 is lower than a measurement temperature T2 of the cooling chamber 25 by a first predetermined temperature X1 or greater, the control part 40 lowers the rotational frequency of the compressor 22.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The technology disclosed herein relates to a refrigerated storage facility. [Background technology]

[0002] A conventional refrigerated storage cabinet is described in Patent Document 1. The refrigerated storage cabinet described in Patent Document 1 includes a storage compartment for storing stored items, a cooler (evaporator) that cools the surrounding air, a cooler compartment (cooling compartment) that houses the cooler, and a circulation fan (evaporator fan) that circulates air between the storage compartment and the cooler compartment, and is capable of performing a cooling operation. During the cooling operation, the air from the storage compartment is sent to the cooler compartment by the circulation fan, cooled as it passes around the cooler, and then sent to the storage compartment. This cools the air in the storage compartment. Furthermore, when the cooling operation is performed, water vapor contained in the air in the storage compartment is cooled by the cooler, which can result in frost forming on the surface of the cooler. Frost on the surface of the cooler inhibits heat exchange between the cooler and the surrounding air, reducing cooling efficiency. For this reason, Patent Document 1 describes a method of melting frost on the cooler by heating the cooler with a defrosting heater. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-89435 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the method of defrosting a cooler using a defrost heater as in Patent Document 1, power is required to operate the defrost heater, resulting in increased power consumption. Furthermore, operating the defrost heater increases the temperature in the cooler compartment, causing air from the cooler compartment to be sent to the storage compartment, which in turn increases the temperature in the storage compartment. Therefore, there is a need for a method of suppressing frost formation in a cooler without using a defrost heater.

[0005] The technology disclosed in this specification was developed based on the above circumstances, and aims to provide a refrigerated storage facility that can suppress frost formation on the cooler without using a defrosting heater. [Means for solving the problem]

[0006] As a means for solving the above problem, the cooling storage facility disclosed in this specification comprises a storage chamber in which stored items are stored, a compressor that compresses a refrigerant, a cooler that cools the surrounding air by evaporating the refrigerant compressed by the compressor, a cooler chamber in which the cooler is housed, a circulation fan that circulates air between the storage chamber and the cooler chamber, a cooler chamber temperature sensor that measures the temperature of the cooler chamber, a cooler temperature sensor that measures the temperature of the cooler, a storage chamber temperature sensor that measures the temperature of the storage chamber, and a control unit, wherein the control unit performs a cooling operation that controls the operation of the compressor and the circulation fan so that the measured temperature of the storage chamber measured by the storage chamber temperature sensor becomes a predetermined target temperature, and further, the control unit reduces the rotation speed of the compressor when the measured temperature of the cooler measured by the cooler temperature sensor remains lower by a first predetermined temperature or more for a first predetermined time or more during the cooling operation.

[0007] In addition, the control unit can be configured to increase the rotation speed of the circulation fan when, during the cooling operation, the measured temperature of the cooler remains lower than the measured temperature of the cooler chamber by a second predetermined temperature or more for a second predetermined time or more and the measured temperature of the cooler chamber is 0°C or higher.

[0008] In addition, the control unit can be configured to reduce the rotation speed of the circulation fan when, during the cooling operation, the measured temperature of the cooler remains lower than the measured temperature of the cooler chamber by a third predetermined temperature or more for a third predetermined time or more. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a refrigerated storage cabinet that can suppress frost formation on a cooler without using a defrosting heater. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a front view showing a cooling storage unit according to an embodiment of the present invention; [Figure 2] Cross-sectional view showing the internal structure of the cooling storage facility [Figure 3] Block diagram showing the electrical configuration of the cooling storage facility [Figure 4] Flowchart showing the process of the control unit related to the compressor [Figure 5] 10 is a flowchart showing the processing of the control unit related to the circulation fan. [Figure 6] 10 is a flowchart showing the processing of a control unit according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] <Embodiment 1> A first embodiment of the present invention will be described with reference to FIGS. 1 to 6. The symbols F, Rr, L, R, U, and D shown in FIGS. 1 and 2 respectively indicate the front and rear in the longitudinal direction of the refrigerated storage cabinet 10, the left and right in the width direction when viewed from the front, and the top and bottom in the vertical direction. In this embodiment, as shown in FIG. 1, an upright refrigerator is exemplified as the refrigerated storage cabinet 10. As shown in FIGS. 1 and 2, the refrigerated storage cabinet 10 includes an insulated box 12 having a storage chamber 11 for accommodating stored items, and a machine chamber 14 provided above the insulated box 12. The front surface of the insulated box 12 (the left side in FIG. 2) is open, and the opening is partitioned by a partition frame 15 extending horizontally. As a result, the storage chamber 11 has two openings 11A, 11A arranged vertically.

[0012] A pair of left and right doors 16, 16 are attached to the insulated box 12 in two vertical rows. Each door 16 is attached to the insulated box 12 at its side edge so as to be rotatable. This allows the opening 11A to be opened and closed by the door 16. The insulated box 12 is supported by legs 13 attached to the four corners of its bottom. As shown in FIG. 2, shelves 17 are provided in the storage compartment 11 in a horizontal direction, and items stored in the storage compartment 11 can be placed on the shelves 17. A cooling device 20 is provided in the machine compartment 14. As shown in FIG. 2, the cooling device 20 (freezing unit) is placed on a unit stand 23. The cooling device 20 includes a condenser 21 equipped with a condenser fan 21A and a compressor 22 that compresses a refrigerant.

[0013] A drain pan 24, which also serves as a cooling duct, is disposed at the top of the insulated box 12, sloping downward toward the rear (right side in FIG. 2 ). This defines a cooler chamber 25 between the unit base 23 and the drain pan 24. A cooler 26 is housed in the cooler chamber 25. More specifically, the cooler 26 is attached to the underside of the unit base 23. The cooler 26 is circulated with the cooling device 20 via a refrigerant pipe (not shown). A flammable refrigerant heavier than air, such as propane or isobutane, is sealed in the refrigerant pipe. The cooler 26 evaporates the refrigerant compressed by the compressor 22, thereby cooling the surrounding air. A motor-driven circulation fan 27 is provided in front of the drain pan 24, and a cool air outlet 28 is formed behind the drain pan 24. Driving the circulation fan 27 allows air to circulate between the storage chamber 11 and the cooler chamber 25.

[0014] During cooling operation, compressor 22, circulation fan 27, and condenser fan 21A are driven. When circulation fan 27 is driven, air in storage chamber 11 is drawn into cooler chamber 25 as shown by arrow P1 in Fig. 2, and then the air is heat exchanged as it passes through cooler 26, generating cool air, which is then blown out from blowout section 28 into storage chamber 11 as shown by arrow P2. This results in a configuration in which cool air is circulated and supplied within storage chamber 11.

[0015] A temperature sensor 29 is disposed above the circulation fan 27 in the cooler chamber 25. The temperature sensor 29 (storage chamber temperature sensor) is capable of measuring the temperature of the air in the storage chamber 11 sucked in by the circulation fan 27 (and thus the temperature inside the storage chamber 11). Since the temperature sensor 29 is disposed in the cooler chamber 25, it can also be used as a sensor (cooler chamber temperature sensor) that measures the temperature of the cooler chamber 25. A cooler temperature sensor 30 that measures the temperature of the cooler 26 is attached to the cooler 26. A defrost heater 31, which is, for example, a sheathed heater, is provided on the underside of the cooler 26. The defrost heater 31 is provided to remove frost that has adhered to the cooler 26.

[0016] Next, we will explain the electrical configuration of the refrigerated storage cabinet 10. As shown in Fig. 3, the refrigerated storage cabinet 10 is equipped with a control unit 40. The control unit 40 is electrically connected to a display unit 41, an operation unit 42, a memory unit 43, a timer unit 44, a condenser fan 21A, a compressor 22, a circulation fan 27, a temperature sensor 29, a cooler temperature sensor 30, and a defrost heater 31.

[0017] The control unit 40 is mainly composed of, for example, a CPU, and the storage unit 43 is composed of, for example, a ROM, a RAM, etc. The control unit 40 executes a computer program stored in the storage unit 43, thereby being able to control the operation of each device connected to the control unit 40 (such as the condenser fan 21A, the compressor 22, the circulation fan 27, and the defrost heater 31). The control unit 40 is housed, for example, in an electrical equipment box 18 (see FIG. 1) arranged in the machine room 14, but is not limited to this.

[0018] The display unit 41 is configured, for example, by a liquid crystal panel, and the operation unit 42 is configured by buttons that can be pressed. As shown in Fig. 1, the front of the machine room 14 is configured by an openable front cover 14A, and the display unit 41 and operation unit 42 are disposed on the back side of the front cover 14A. An operator can view the display unit 41 from the front through a transparent member 19 (such as glass) provided on the front cover 14A.

[0019] Furthermore, by opening the front cover 14A, the operator can operate the operation unit 42. By operating the operation unit 42, the operator can operate the cooling storage cabinet 10 and perform various settings (such as changing the target set temperature). Furthermore, the timer unit 44 is configured to measure the time.

[0020] Next, the processing of the control unit 40 will be described. In this embodiment, a cooling operation in which the inside of the storage chamber 11 is cooled by operating the compressor 22 and the circulation fan 27, and a defrosting operation that is performed after the cooling operation and removes frost that has adhered to the cooler 26, are alternately performed. The defrosting operation is performed every predetermined time (for example, every few hours), but is not limited to this.

[0021] During cooling operation, the control unit 40 controls the operation of the compressor 22 and the circulation fan 27 so that the temperature reaches a predetermined target temperature. Specifically, the control unit 40 stops the compressor 22 and the circulation fan 27 when the temperature of the storage compartment 11 measured by the temperature sensor 29 becomes lower than the target temperature by a predetermined value A1, and drives the compressor 22 and the circulation fan 27 when the temperature of the storage compartment 11 measured by the temperature sensor 29 becomes higher than the target temperature by a predetermined value A2. This allows the temperature in the storage compartment 11 to be maintained near the target temperature (in the range between (target temperature minus predetermined value A1) and (target temperature plus predetermined value A2)). The target temperature can be set by an operator operating the operation unit 42, and the set target temperature is stored in the memory unit 43. The target temperature can be set, for example, within a range from -6°C to +12°C, but is not limited thereto.

[0022] In the defrosting operation, the control unit 40 performs heater defrosting, which heats the cooler 26 using the defrost heater 31. Alternatively, as a defrosting operation, the control unit 40 may perform off-cycle defrosting, which stops the compressor 22 and operates the circulation fan 27. The control unit 40 completes the defrosting operation when the temperature measured by the cooler temperature sensor 30 reaches a preset defrost end temperature, and then performs the next cooling operation. When heater defrosting is performed, the defrost heater 31 is turned off after the temperature reaches the defrost end temperature, and the next cooling operation is performed after a predetermined draining time has elapsed.

[0023] 4, if the measured temperature T1 of the cooler 26 measured by the cooler temperature sensor 30 remains lower than the measured temperature T2 of the cooler chamber 25 measured by the temperature sensor 29 by at least a first predetermined temperature X1 for at least a first predetermined time Y1 ("YES" in step S11), the control unit 40 reduces the rotation speed of the compressor 22 (step S12). For example, the first predetermined temperature X1 is set to 10 K, and the first predetermined time Y1 is set to 5 minutes, but these are not limiting. The compressor 22 may be an inverter compressor capable of switching the rotation speed in multiple stages (e.g., six stages), and the control unit 40 reduces the rotation speed of the compressor 22 by one stage, for example.

[0024] Furthermore, if, after reducing the rotation speed of the compressor 22 by one step, the state in which the measured temperature T1 of the cooler 26 is lower than the measured temperature T2 of the cooler chamber 25 by a predetermined temperature XA or more continues for a predetermined time YA or more ("YES" in step S13), the control unit 40 further reduces the rotation speed of the compressor 22 by one step (step S14). Note that, for example, the predetermined temperature XA is set to a value (e.g., 20 K) higher than the first predetermined temperature X1, and the predetermined time YA is set to a value (e.g., 10 minutes) higher than the first predetermined time Y1, but is not limited to this.

[0025] The control unit 40 continues the cooling operation by operating the compressor 22 at the reduced rotation speed until the defrosting operation is performed, and after the defrosting operation is performed, operates the compressor 22 at the original rotation speed (the rotation speed before the reduction) to perform the cooling operation.

[0026] 5, when the state in which the measured temperature T1 of the cooler 26 is lower than the measured temperature T2 of the cooler chamber 25 by at least a second predetermined temperature X2 continues for at least a second predetermined time Y2 during the cooling operation ("YES" in step S21) and when the measured temperature T2 of the cooler chamber 25 is at least 0°C ("YES" in step S22), the control unit 40 increases the rotation speed of the circulation fan 27 (step S23). Note that, for example, the second predetermined temperature X2 is set to 20K and the second predetermined time Y2 is set to 5 minutes, but is not limited to this.

[0027] The circulation fan 27 has a configuration in which the rotation speed can be changed, and for example, a DC brushless motor capable of changing the rotation speed can be used as a drive motor provided in the circulation fan 27. Note that until the defrosting operation is performed, the control unit 40 continues the cooling operation by operating the circulation fan 27 at the increased rotation speed, and after the defrosting operation is performed, the control unit 40 performs the cooling operation by operating the circulation fan 27 at the original rotation speed (the rotation speed before the increase).

[0028] Next, the effects of this embodiment will be described. In this embodiment, during cooling operation, air from the storage compartment 11 is sent to the cooler compartment 25 by the circulation fan 27, cooled by heat exchange as it passes around the cooler 26, and then sent to the storage compartment 11. If frost forms on the cooler 26, heat exchange by the cooler 26 is hindered, and the temperature of the cooler 26 is likely to be lower than the temperature of the cooler compartment 25 (the ambient temperature of the cooler 26). Therefore, if the measured temperature T1 of the cooler 26 remains lower than the measured temperature T2 of the cooler compartment 25 by at least a first predetermined temperature X1 for at least a first predetermined time Y1, the control unit 40 determines that frost has formed on the cooler 26 and reduces the rotation speed of the compressor 22, thereby reducing the cooling capacity of the cooler 26. This reduces frost formation on the cooler 26.

[0029] In addition, the control unit 40 increases the rotation speed of the circulation fan 27 when, during cooling operation, the measured temperature T1 of the cooler 26 remains lower than the measured temperature T2 of the cooler chamber 25 by at least a second predetermined temperature X2 for at least a second predetermined time Y2 and when the measured temperature of the cooler chamber 25 is at least 0°C.

[0030] By increasing the rotation speed of the circulation fan 27, it is possible to increase the amount of air circulated between the storage chamber 11 and the cooler chamber 25. This increases the amount of air (air at 0°C or higher) passing around the cooler 26, thereby suppressing frost formation on the cooler 26. Furthermore, in this embodiment, since frost formation on the cooler 26 can be suppressed, the time required for defrosting operation by the defrost heater 31 can be reduced, thereby reducing power consumption.

[0031] <Embodiment 2> Next, a second embodiment of the present invention will be described. The same components as those in the above embodiment are designated by the same reference numerals, and redundant description will be omitted. In this embodiment, the processing of the control unit 40 during cooling operation differs from that in the above embodiment. In this embodiment, as shown in FIG. 6, when the measured temperature T1 of the cooler 26 remains lower than the measured temperature T2 of the cooler chamber 25 by at least a third predetermined temperature X3 for at least a third predetermined time Y3 ("YES" in step S31) during cooling operation, the control unit 40 reduces the rotation speed of the circulation fan 27 (step S32). For example, the third predetermined temperature X3 is set to 10 K, and the third predetermined time Y3 is set to 5 minutes, but this is not limiting.

[0032] By reducing the rotation speed of the circulation fan 27, it is possible to reduce the amount of air circulating between the storage chamber 11 and the cooler chamber 25. This reduces the amount of air passing around the cooler 26, thereby suppressing frost formation on the cooler 26. As described in the first embodiment above, when the measured temperature T2 of the cooler chamber 25 is 0°C or higher, it is possible to increase the rotation speed of the circulation fan 27 to increase the amount of air (air at 0°C or higher) passing around the cooler 26, thereby suppressing frost formation on the cooler 26.

[0033] Therefore, in this embodiment, if the measured temperature T1 remains lower than the measured temperature T2 by at least a third predetermined temperature X3 for at least a third predetermined time Y3 during cooling operation (if it is thought that frost has formed on the cooler 26), the rotation speed of the circulation fan 27 may be increased if the measured temperature T2 is 0°C or higher, and the rotation speed of the circulation fan 27 may be decreased if the measured temperature T2 is lower than 0°C.

[0034] The control unit 40 continues the cooling operation by operating the circulation fan 27 at the changed rotation speed until the defrosting operation is performed, and after the defrosting operation is performed, it operates the circulation fan 27 at the original rotation speed (the rotation speed before the change) to perform the cooling operation.

[0035] <Other embodiments> The technology disclosed in this specification is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included in the technical scope. (1) In the above embodiment, a configuration was exemplified in which the temperature sensor 29 serves as both a cooler chamber temperature sensor and a storage chamber temperature sensor, but this is not limited to this, and the cooler chamber temperature sensor and the storage chamber temperature sensor may each be separate temperature sensors. (2) In the above embodiment, a four-door vertical refrigerator is used as the refrigerated storage cabinet 10, but the present invention is not limited to this. (3) The values ​​of the predetermined temperature XA, the first predetermined temperature X1, the second predetermined temperature X2, the predetermined time YA, the first predetermined time Y1, and the second predetermined time Y2 are not limited to those described above and can be changed as appropriate. For example, they can be set by conducting a test run in advance and determining the correlation between the state of frost on the cooler 26 and the above temperatures XA, X1, X2 and the predetermined times YA, Y1, Y2. [Explanation of symbols]

[0036] 10... refrigerated storage, 11... storage chamber, 22... compressor, 25... cooler chamber, 26... cooler, 27... circulation fan, 29... temperature sensor (storage chamber temperature sensor, cooler chamber temperature sensor), 30... cooler temperature sensor, 40... control unit

Claims

1. a storage chamber in which the stored items are stored; a compressor that compresses a refrigerant; a cooler that cools surrounding air by evaporating the refrigerant compressed by the compressor; a cooler chamber in which the cooler is accommodated; a circulation fan that circulates air between the storage chamber and the cooler chamber; a cooler chamber temperature sensor for measuring the temperature of the cooler chamber; a cooler temperature sensor for measuring the temperature of the cooler; a storage chamber temperature sensor for measuring the temperature of the storage chamber; a control unit, the control unit executes a cooling operation to control operations of the compressor and the circulation fan so that the measured temperature of the storage compartment measured by the storage compartment temperature sensor becomes a predetermined target temperature; Furthermore, the control unit reduces the rotation speed of the compressor when, during the cooling operation, the measured temperature of the cooler measured by the cooler temperature sensor remains lower by a first predetermined temperature or more than the measured temperature of the cooler chamber measured by the cooler chamber temperature sensor for a first predetermined time or more.

2. The cooling storage facility described in claim 1, wherein the control unit increases the rotation speed of the circulation fan when, during the cooling operation, the measured temperature of the cooler remains lower than the measured temperature of the cooler chamber by a second predetermined temperature or more for a second predetermined time or more and when the measured temperature of the cooler chamber is 0°C or higher.

3. The cooling storage facility described in claim 1, wherein the control unit reduces the rotation speed of the circulation fan when the measured temperature of the cooler remains lower than the measured temperature of the cooler chamber by a third predetermined temperature or more for a third predetermined time or more during the cooling operation.

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