JP7630376B2 - Cooling Storage - Google Patents

Description

The technology disclosed in this specification relates to refrigerated storage.

The one described in the following Patent Document 1 is known as an example of a conventional cooling storage. The cooling storage described in Patent Document 1 includes a cooling unit having an inverter compressor, a condenser, a condenser fan, and an evaporator, a clogging thermistor that detects the temperature of the condenser, and a control unit. The control unit executes a cooling operation in which the cooling unit is operated to cool the interior of the storage, a defrosting operation in which the inverter compressor is stopped and the evaporator is defrosted when a predetermined defrost start condition is met, a temperature detection process in which the condenser fan is rotated in the defrosting operation, and the clogging thermistor detects the temperature of the condenser when a predetermined time has elapsed since the condenser fan started to rotate, and a restart process in which the defrosting operation is terminated and the cooling operation is restarted when a predetermined defrost end condition is met, and if the defrosting operation is terminated before the predetermined time has elapsed, the restart process waits for the cooling operation to be restarted until the predetermined time has elapsed.

JP 2020-85408 A

In the cooling storage described in the above-mentioned Patent Document 1, the condenser fan continues to rotate for a predetermined time (10 minutes) from the start of off-cycle defrosting, which defrosts without using a heater, and after the predetermined time has elapsed, the outside air temperature is obtained by obtaining the condenser temperature from a clogged thermistor. In this way, in Patent Document 1, the condenser fan continues to rotate for the predetermined time regardless of the length of time required for off-cycle defrosting, which poses a problem in terms of reducing power consumption.

The technology described in this specification was developed based on the above circumstances, and aims to reduce power consumption.

(1) The cooling storage related to the technology described in this specification includes a storage body having a storage chamber, an evaporator that constitutes a refrigeration cycle and cools the air in the storage chamber, a condenser that constitutes the refrigeration cycle together with the evaporator, a condenser fan that blows air to the condenser, a sensor that detects the temperature of the condenser or near the condenser, and a control unit that controls the refrigeration cycle to perform a cooling operation and a defrosting operation to melt frost that has adhered to the evaporator, and the control unit stops the condenser fan during the defrosting operation, rotates the condenser fan between the end of the defrosting operation and the restart of the cooling operation if the operating time of the defrosting operation is less than the reference time, and controls the condenser fan so that the load is lighter than when the time between the end of the defrosting operation and the restart of the cooling operation is less than the reference time if the operating time of the defrosting operation is equal to or longer than the reference time, and obtains the temperature detected by the sensor after the defrosting operation is completed as the outside air temperature.

When the cooling operation is performed by the control unit, the refrigeration cycle is controlled, and the air inside the cabinet is cooled by the evaporator. The condenser is cooled by blowing air by the condenser fan. When the defrosting operation is performed by the control unit, the frost on the evaporator is melted. The condenser fan is stopped by the control unit during the defrosting operation. If the operation time of the defrosting operation does not reach the reference time, the condenser fan is rotated by the control unit between the end of the defrosting operation and the restart of the cooling operation. At this time, the condenser fan is controlled by the control unit so that the load is heavier than when the operation time of the defrosting operation is equal to or longer than the reference time. If the operation time of the defrosting operation does not reach the reference time, it is assumed that the temperature of the condenser or the vicinity of the condenser has not been sufficiently reduced. In this case, if the control unit controls the condenser fan to increase the load, the temperature of the condenser or the vicinity of the condenser can be sufficiently reduced. As a result, the temperature of the condenser or the vicinity of the condenser detected by the sensor after the end of the defrosting operation with an operation time that does not reach the reference time can be made equal to the outside air temperature. On the other hand, when the operation time of the defrosting operation is equal to or longer than the reference time, the control unit controls the condenser fan so that the load is lighter than when the operation time of the defrosting operation does not reach the reference time between the end of the defrosting operation and the restart of the cooling operation. If the operation time of the defrosting operation is equal to or longer than the reference time, it is assumed that the temperature of the condenser or the vicinity of the condenser has sufficiently dropped to be close to the outside air temperature. In this case, even if the control unit controls the condenser fan so that the load is lighter, it is highly certain that the temperature of the condenser or the vicinity of the condenser detected by the sensor after the end of the defrosting operation that has been operated for the reference time or longer is equivalent to the outside air temperature. Compared to the conventional method of rotating the condenser fan for a fixed time regardless of the operation time of the defrosting operation, the amount of power consumption required to rotate the condenser fan can be reduced. Moreover, the control unit can obtain the temperature of the condenser or the vicinity of the condenser detected by the sensor after the end of the defrosting operation as the outside air temperature, regardless of whether the operation time of the defrosting operation is equal to or longer than the reference time. Therefore, compared to the conventional method of obtaining the outdoor air temperature after the defrosting operation is completed or during the defrosting operation, the control related to obtaining the outdoor air temperature is simplified. In addition, a dedicated sensor for obtaining the outdoor air temperature is not required.

(2) In addition to the above (1), the control unit may control the condenser fan so that, if the operation time of the defrosting operation is equal to or longer than the reference time, the control unit does not rotate the condenser fan between the end of the defrosting operation and the restart of the cooling operation, whereas, if the operation time of the defrosting operation is less than the reference time, the control unit controls the condenser fan to rotate between the end of the defrosting operation and the restart of the cooling operation. In this way, if the operation time of the defrosting operation is equal to or longer than the reference time, the control unit does not rotate the condenser fan between the end of the defrosting operation and the restart of the cooling operation, so that the load on the condenser fan is lighter than when the operation time of the defrosting operation is less than the reference time. Therefore, it is possible to achieve even lower power consumption than when the control unit rotates the condenser fan between the end of the defrosting operation and the restart of the cooling operation when the operation time of the defrosting operation is equal to or longer than the reference time.

(3) In addition to the above (2), the control unit may control the condenser fan to start rotating the condenser fan in a state where the refrigeration cycle is stopped after the defrosting operation is terminated and before the cooling operation is resumed if the operating time of the defrosting operation does not reach the reference time. When the defrosting operation is terminated, the operating time of the defrosting operation is determined. If the determined operating time of the defrosting operation does not reach the reference time, the control unit can rotate the condenser fan as much as necessary according to the operating time of the defrosting operation between the termination of the defrosting operation and the resumption of the cooling operation. This further reduces power consumption and increases the certainty that the temperature of the condenser or near the condenser will be equivalent to the outside air temperature.

(4) In addition to (1) above, the control unit of the cooling storage facility may control the condenser fan using a first reference time and a second reference time shorter than the first reference time as the reference time, and the control unit may control the condenser fan so as not to rotate the condenser fan between the end of the defrosting operation and the restart of the cooling operation if the operating time of the defrosting operation is equal to or longer than the first reference time, to rotate the condenser fan for a first time between the end of the defrosting operation and the restart of the cooling operation if the operating time of the defrosting operation is equal to or longer than the second reference time and does not meet the first reference time, and to rotate the condenser fan for a second time longer than the first time between the end of the defrosting operation and the restart of the cooling operation if the operating time of the defrosting operation is equal to or longer than the second reference time and does not meet the first reference time. When the operation time of the defrosting operation is equal to or longer than the first reference time, the control unit does not rotate the condenser fan between the end of the defrosting operation and the restart of the cooling operation, so the load on the condenser fan is the lightest compared to when the operation time of the defrosting operation is shorter than the first reference time. When the operation time of the defrosting operation is equal to or longer than the second reference time and shorter than the first reference time, the control unit rotates the condenser fan for a first time shorter than the second time between the end of the defrosting operation and the restart of the cooling operation, so the load on the condenser fan is heavier than when the operation time of the defrosting operation is equal to or longer than the first reference time, but is lighter than when the operation time of the defrosting operation is shorter than the second reference time. When the operation time of the defrosting operation is shorter than the second reference time, the control unit rotates the condenser fan for a second time longer than the first time between the end of the defrosting operation and the restart of the cooling operation, so the load on the condenser fan is the heaviest compared to when the operation time of the defrosting operation is equal to or longer than the second reference time. As described above, the load on the condenser fan is more precisely controlled by the control unit depending on the length of the defrosting operation, which appropriately reduces power consumption and increases the certainty that the temperature of the condenser or near the condenser will be equivalent to the outside air temperature.

(5) In addition to the above (1), the control unit may control the condenser fan to rotate for a first time between the end of the defrosting operation and the restart of the cooling operation if the operation time of the defrosting operation is equal to or longer than the reference time, whereas the control unit may control the condenser fan to rotate for a second time longer than the first time between the end of the defrosting operation and the restart of the cooling operation if the operation time of the defrosting operation is less than the reference time. In this way, when the operation time of the defrosting operation is equal to or longer than the reference time, the control unit rotates the condenser fan for a first time shorter than the second time between the end of the defrosting operation and the restart of the cooling operation, so that the load on the condenser fan is lighter than when the operation time of the defrosting operation is less than the second reference time. Therefore, if the operation time of the defrosting operation is equal to or longer than the reference time, the temperature of the condenser or near the condenser is more likely to be equivalent to the outside air temperature than when the control unit does not rotate the condenser fan between the end of the defrosting operation and the restart of the cooling operation.

(6) In addition to any one of (1) to (5), the cooling storage unit may be provided with an internal fan disposed in the storage unit body for circulating air inside the storage unit, and the control unit may perform off-cycle defrosting as the defrosting operation by stopping the operation of the refrigeration cycle and rotating the internal fan. The operating time of off-cycle defrosting tends to be longer than when heater defrosting using a defrost heater for heating an evaporator is performed as the defrosting operation. Therefore, when off-cycle defrosting is performed as the defrosting operation, there are many cases where the operating time exceeds the reference time, and in such cases, even if the load on the condenser fan is reduced, the temperature of the condenser or near the condenser is likely to become equal to the outside air temperature. In this way, if the load on the condenser fan is reduced more frequently, it is favorable for achieving low power consumption.

The technology described in this specification can reduce power consumption.

FIG. 1 is a perspective view of a cooling storage unit according to a first embodiment; Schematic cross-section of a cooling storage facility Block diagram showing the electrical configuration of the cooling storage A timing chart showing the cooling operation and off-cycle defrosting operation of a cooling storage unit when the operating time of the off-cycle defrosting operation is equal to or longer than a reference time. A timing chart showing the cooling operation and off-cycle defrosting operation of a cooling storage unit, in which the operation time of the off-cycle defrosting operation does not reach a reference time. Flowchart showing control from the start of off-cycle defrosting operation to the transition to cooling operation FIG. 10 is a timing chart showing the cooling operation and the off-cycle defrosting operation of the cooling storage unit according to the second embodiment, in which the operation time of the off-cycle defrosting operation is equal to or longer than a first reference time. A timing chart showing a cooling operation and an off-cycle defrosting operation of a cooling storage unit, in which the operation time of the off-cycle defrosting operation is equal to or longer than a second reference time and does not reach a first reference time. A timing chart showing a cooling operation and an off-cycle defrosting operation of a cooling storage unit, in which the operation time of the off-cycle defrosting operation does not reach a second reference time. A timing chart showing the cooling operation and the off-cycle defrosting operation of the cooling storage unit according to the third embodiment, in which the operation time of the off-cycle defrosting operation is equal to or longer than a reference time. A timing chart showing the cooling operation and off-cycle defrosting operation of a cooling storage unit, in which the operation time of the off-cycle defrosting operation does not reach a reference time. A flowchart showing control related to a defrosting operation performed in a freezer compartment of a cooling storage unit according to a fourth embodiment. A flowchart showing control related to a defrosting operation performed in a refrigerator compartment of a cooling storage unit. FIG. 13 is a block diagram showing the electrical configuration of a cooling storage unit according to a fifth embodiment. A flowchart showing control related to a defrosting operation performed in a freezer compartment of a refrigerated storage facility. A flowchart showing control related to a defrosting operation performed in a refrigerator compartment of a cooling storage unit. FIG. 13 is a block diagram showing the electrical configuration of a cooling storage unit according to a sixth embodiment. A timing chart for explaining the detection of an abnormality in the pressure of a condenser during cooling operation. FIG. 10 is a timing chart for explaining detection of an abnormality in pressure of a condenser using a second elapsed time timer and a third elapsed time timer during a cooling operation. FIG. 10 is a timing chart for explaining detection of an abnormality in pressure of a condenser using a second elapsed time timer and a third elapsed time timer during a cooling operation.

<Embodiment 1>
A first embodiment will be described with reference to Figs. 1 to 6. In this embodiment, a horizontal (table-type) cooling storage 10 is illustrated. Figs. 1 and 2 show an X-axis, a Y-axis, and a Z-axis, and each axis direction is depicted as being in the direction shown in each drawing. Among these, the Z-axis direction is approximately the vertical direction, and the X-axis and Y-axis directions are approximately the horizontal direction. Furthermore, unless otherwise specified, the description of up and down is based on the vertical direction.

As shown in Figs. 1 and 2, the cooling storage 10 has a storage body 11, which is a horizontally long box. The storage body 11 is mainly made of metal plates such as stainless steel plates. The storage body 11 has a storage chamber 12 in which stored items such as food ingredients are stored, and a machine chamber 13 in which various devices are stored. The storage chamber 12 has an opening at the front, and the opening can be opened and closed by a pair of insulating doors 14 that open like a double door. When the insulating doors 14 are open, stored items such as food ingredients can be put in and taken out of the storage chamber 12 through the opening at the front of the storage chamber 12. The storage chamber 12 includes one or both of a refrigerator chamber in which stored items are refrigerated and a freezer chamber in which stored items are frozen. In addition, a condensation prevention heater 12A is embedded in the periphery of the opening of the storage chamber 12 to which the insulating door 14 is attached (see Fig. 3). The dew prevention heater 12A is, for example, a cord heater, and is an accessory device for suppressing dew that may occur near the opening of the storage chamber 12. A workbench 15 is provided on the top surface of the storage chamber main body 11. The user of this cooling storage chamber 10 can perform tasks such as cooking the stored items taken out of the storage chamber 12 on the workbench 15, which is highly convenient. The storage chamber main body 11 is also supported by four legs 16 provided on the bottom surface.

The machine room 13 is provided to the side of the storage room 12 (left side in Figs. 1 and 2). The machine room 13 is formed in a box shape with an opening on the front, and a panel unit 17 is arranged to cover this opening. A cooling unit 18 is stored in the machine room 13 so that it can be pulled out through the opening. When storing or removing the cooling unit 18, the panel unit 17 is removed and the opening is opened. The cooling unit 18 is equipped with at least a base 19, a compressor 20, a condenser 21, a cooler (evaporator) 22, and an internal fan 23. Of these, the compressor 20 is inverter-controlled and its rotation speed can be changed as appropriate.

As shown in FIG. 2, the machine room 13 is divided into upper and lower parts by a partition wall 13A, and the upper part houses the cooler 22 and an electrical box, and the lower part houses the compressor 20 and the condenser 21. The compressor 20 and the condenser 21 are mounted on a base 19 and are housed in the lower part of the machine room 13 together with the base 19. A condenser fan 25 is provided on the rear side of the condenser 21 to blow air to the condenser 21 to cool the condenser 21 (see FIG. 3). In addition, a filter is provided on the front side of the condenser 21 to prevent dust in the air from adhering to the condenser 21 and reducing the condensing capacity. If dust adheres to the filter and causes clogging, sufficient heat exchange will not occur between the condenser 21 and the outside air even if the condenser fan 25 rotates, and the cooling efficiency may decrease. Therefore, a clogging temperature sensor (sensor, condenser temperature sensor) 21A is attached to the piping of the condenser 21 via a holder to detect clogging of the filter. The clogging temperature sensor 21A is specifically a temperature thermistor, and can detect the temperature of the condenser 21 or the vicinity of the condenser 21. Because the temperature of the condenser 21 or the vicinity of the condenser 21 varies depending on the amount of dust adhering to the filter, it is possible to detect whether or not the filter is clogged based on the temperature detected by the clogging temperature sensor 21A.

The upper part of the machine room 13 constitutes the cooler room 24 in which the cooler 22 is housed. A duct 26 is provided between the cooler room 24 and the adjacent storage room 12 to separate them while keeping them in communication with each other. The lower part of the duct 26 and the inner wall surface of the storage body 11 form an intake port 26A for drawing air from the storage room 12 into the cooler room 24. The upper part of the duct 26 and the inner wall surface of the storage body 11 form an outlet port 26B for blowing air from the cooler room 24 into the storage room 12. The cooler 22 is connected to the compressor 20 and the condenser 21 via piping to form a refrigeration cycle. The internal fan 23 is disposed adjacent to the cooler 22 on the storage room 12 side, and is capable of blowing cold air generated by the cooler 22 into the storage room 12 from the outlet port 26B.

The cooler 22 is fitted with a defrost heater (defrost heater, heating unit) 27 capable of heating the cooler 22 during defrosting, and a defrost temperature sensor (cooler temperature sensor) 28 that detects the temperature of the cooler 22 or near the cooler 22 (see FIG. 3). In addition, an internal temperature sensor 29 that detects the temperature inside the cooler (in the storage chamber 12 and the cooler chamber 24) is provided inside the storage body 11 (for example, near the suction port 26A). Specifically, the defrost temperature sensor 28 and the internal temperature sensor 29 are each a temperature thermistor.

When the cooling unit 18 is activated, the water vapor around the cooler 22 is cooled and solidified by the cooler 22, causing frost to form on the surface of the cooler 22. The frost on the cooler 22 melts when the cooling storage 10 starts defrosting operation. There are two types of defrosting methods for the defrosting operation: a heater defrost method (an example of a heating defrost method) and an off-cycle defrost method (an example of a heating suppression defrost method). In the heater defrost method, the cooler 22 is heated by the defrost heater 27 to melt the frost on the cooler 22. In the off-cycle defrost method, the cooler 22 is not heated by the defrost heater 27, and the frost on the cooler 22 is melted by stopping the cooling unit 18 (refrigeration cycle) and increasing the temperature inside the storage.

As shown in FIG. 3, the cooling storage 10 is provided with a control unit 30 that electrically controls various devices. The control unit 30 is configured, for example, by a control board provided in an electrical equipment box housed in the machine room 13. The control unit 30 is electrically connected to the various devices. The control unit 30 controls the cooling operation and defrosting operation, etc. (control of the compressor 20, the internal fan 23, the condenser fan 25, the defrost heater 27, etc.).

In detail, as shown in FIG. 3, the control unit 30 is electrically connected to the compressor 20, the interior fan 23, the condenser fan 25, the defrost heater 27, the defrost temperature sensor 28, the interior temperature sensor 29, the condensation prevention heater 12A, and the clogging temperature sensor 21A, as well as the defrost cycle timer 31. The defrost cycle timer 31 counts the defrost cycle time Td, which is the time related to the cycle in which the defrost operation is performed, and is provided, for example, on the control board constituting the control unit 30. The control board may be provided with a memory (storage unit) that stores the time counted by the defrost cycle timer 31. The time stored in the memory may be readable by the control unit 30. The control unit 30 performs the cooling operation by controlling the compressor 20, the interior fan 23, and the condenser fan 25. During the cooling operation, the control unit 30 appropriately operates the compressor 20, the interior fan 23, and the condenser fan 25 to operate the refrigeration cycle, while stopping the defrost heater 27. In particular, when the control unit 30 operates the condenser fan 25, it can control the operating speed (rotation speed) of the condenser fan 25 in eight stages, for example, from the lowest speed 0 to the highest speed 7. During the defrosting operation, the control unit 30 stops at least the compressor 20 and the condenser fan 25 and does not operate the refrigeration cycle, regardless of the type of defrosting operation. When performing a heater defrosting operation (hereinafter referred to as heater defrosting operation (heater defrost)), the control unit 30 operates the defrost heater 27 while stopping the compressor 20, the interior fan 23, and the condenser fan 25. When performing a defrosting operation using an off-cycle defrosting method (hereinafter referred to as off-cycle defrosting operation (off-cycle defrost)), the control unit 30 stops the compressor 20, the condenser fan 25, and the defrost heater 27 while operating the interior fan 23.

Specifically, the control unit 30 performs a cooling operation so that the inside temperature detected by the inside temperature sensor 29 becomes the inside temperature set by the user. This inside temperature setting can be changed as appropriate, for example, even during the cooling operation. When the control unit 30 starts the cooling operation, it starts counting (timekeeping) by the defrost cycle timer 31. When the time counted by the defrost cycle timer 31 reaches the defrost cycle time Td, the control unit 30 ends the cooling operation and starts a defrost operation of any method. In this embodiment, the defrost cycle time Td is, for example, 6 hours. The control unit 30 determines which method of defrost operation to perform based on a predetermined condition (for example, the relationship between the inside temperature setting or the temperature detected by the clogging temperature sensor 21A and a predetermined threshold value) that is assumed to reflect the amount of frost on the cooler 22. When the defrost operation is started, the control unit 30 ends the defrost operation when the temperature detected by the defrost temperature sensor 29 becomes a predetermined defrost end temperature te (for example, 10°C) regardless of the method of defrost operation. When performing the heater defrost operation, the control unit 30 waits for a predetermined time (water draining time) between stopping the defrost heater 27 and terminating the heater defrost operation in order to promote the removal of moisture adhering to the cooler 22. When the defrost operation is terminated, the control unit 30 starts the cooling operation again and starts counting by the defrost cycle timer 31. When the time counted by the defrost cycle timer 31 reaches the defrost cycle time Td, the control unit 30 starts a defrost operation of either method, repeating this cycle.

The temperature of the condenser 21 or the vicinity of the condenser 21 detected by the clogging temperature sensor 21A is higher than the outside air temperature due to heat generated by the condenser 21 while the cooling operation is being performed and the refrigeration cycle is operating, but becomes equal to the outside air temperature after a certain time has passed since the operation of the refrigeration cycle is stopped. Furthermore, when the condenser fan 25 is rotated while the operation of the refrigeration cycle is stopped, the temperature of the condenser 21 or the vicinity of the condenser 21 detected by the clogging temperature sensor 21A decreases as the condenser 21 is efficiently air-cooled, and the higher the load on the condenser fan 25 is, the shorter the time required for the temperature to become equal to the outside air temperature tends to be. In contrast, in the past, the condenser fan was kept rotating for a predetermined time regardless of the length of time required for the off-cycle defrost operation. This caused a problem in achieving low power consumption.

Therefore, the control unit 30 according to the present embodiment controls the condenser fan 25 between the end of the defrosting operation and the restart of the cooling operation so that the load is lighter when the operation time of the defrosting operation is equal to or longer than the reference time K (e.g., 30 minutes) than when the operation time of the defrosting operation is shorter than the reference time K. The control unit 30 is electrically connected to a defrosting operation timer 32 that counts (times) the operation time of the defrosting operation. The defrosting operation timer 32 is provided, for example, on a control board constituting the control unit 30, similar to the defrosting cycle timer 31. The time counted by the defrosting operation timer 32 may be stored in the memory of the control board and readable by the control unit 30. The control unit 30 starts counting (timekeeping) by the defrosting operation timer 32 when the defrosting operation starts, and ends counting by the defrosting operation timer 32 when the defrosting operation ends. Then, when the operation time of the defrosting operation counted by the defrosting operation timer 32 is less than the reference time K, the control unit 30 controls the condenser fan 25 so that the load is heavier than when the operation time of the defrosting operation is equal to or greater than the reference time K between the end of the defrosting operation and the restart of the cooling operation. When the operation time of the defrosting operation is less than the reference time K, it is assumed that the temperature of the condenser 21 or the vicinity of the condenser 21 has not sufficiently decreased. In this case, if the control unit 30 controls the condenser fan 25 so that the load is heavier between the end of the defrosting operation and the restart of the cooling operation, the temperature of the condenser 21 or the vicinity of the condenser 21 can be sufficiently decreased by the air blown from the condenser fan 25 to be equal to the outside air temperature. On the other hand, when the operation time of the defrosting operation counted by the defrosting operation timer 32 is equal to or greater than the reference time K, the control unit 30 controls the condenser fan 25 so that the load is lighter than when the operation time of the defrosting operation is less than the reference time K between the end of the defrosting operation and the restart of the cooling operation. If the operation time of the defrosting operation is equal to or longer than the reference time K, it is assumed that the temperature of the condenser 21 or the vicinity of the condenser 21 has sufficiently dropped and is close to the outside air temperature. In this case, even if the control unit 30 controls the condenser fan 25 to reduce the load between the end of the defrosting operation and the restart of the cooling operation, it is highly likely that the temperature of the condenser 21 or the vicinity of the condenser 21 will be equivalent to the outside air temperature. According to this embodiment, the amount of power consumption required to rotate the condenser fan 25 can be reduced compared to the conventional method in which the condenser fan 25 is rotated for a fixed time regardless of the operation time of the defrosting operation.

In particular, in this embodiment, the control unit 30 causes the defrost operation timer 32 to count the operation time of the off-cycle defrost operation, and controls the condenser fan 25 between the end of the off-cycle defrost operation and the restart of the cooling operation so that the load is lighter when the counted operation time is equal to or greater than the reference time K than when the reference time K is not reached. The off-cycle defrost operation tends to have a longer operation time than the heater defrost operation. Therefore, when the off-cycle defrost operation is performed, the operation time is often equal to or greater than the reference time K, and in such cases, even if the load on the condenser fan 25 is reduced, the temperature of the condenser 21 or near the condenser 21 is likely to become equal to the outside air temperature. In this way, if the load on the condenser fan 25 is reduced more frequently, it is favorable for achieving low power consumption.

The control unit 30 acquires the temperature detected by the clogging temperature sensor 21A after the off-cycle defrosting operation is completed as the outdoor air temperature, regardless of whether the operation time of the off-cycle defrosting operation is equal to or longer than the reference time K. In other words, the control unit 30 does not acquire the temperature detected by the clogging temperature sensor 21A during the off-cycle defrosting operation as the outdoor air temperature. Therefore, compared to the conventional method of acquiring the outdoor air temperature after the defrosting operation is completed or during the defrosting operation, the control related to the acquisition of the outdoor air temperature is simplified. In addition, a dedicated sensor for acquiring the outdoor air temperature is not required. The control unit 30 can use the acquired outdoor air temperature, for example, to control the cooling operation or defrosting operation performed later, or to display the outdoor air temperature on the display unit.

In detail, when the operation time of the off-cycle defrosting operation is set to be equal to or longer than the reference time K, the control unit 30 acquires the temperature detected by the clogging temperature sensor 21A at the timing of the end of the off-cycle defrosting operation as the outside air temperature. More specifically, when the operation time of the off-cycle defrosting operation is equal to or longer than the reference time K, the control unit 30 immediately resumes the cooling operation when the off-cycle defrosting operation is ended, and does not rotate the condenser fan 25 as in the case where the operation time of the off-cycle defrosting operation does not reach the reference time K described below. In other words, when the operation time of the off-cycle defrosting operation is set to be equal to or longer than the reference time K, there is no condenser fan operation period (condenser fan rotation period) during which the condenser fan 25 rotates between the off-cycle defrosting operation period and the cooling operation period. In this way, when the operating time of the off-cycle defrost operation is equal to or longer than the reference time K, the control unit 30 controls the condenser fan 25 not to rotate between the end of the off-cycle defrost operation and the restart of the cooling operation, so the load on the condenser fan 25 is lighter than when the operating time of the off-cycle defrost operation does not reach the reference time K. Therefore, even lower power consumption can be achieved compared to when the control unit rotates the condenser fan 25 between the end of the off-cycle defrost operation and the restart of the cooling operation when the operating time of the off-cycle defrost operation is equal to or longer than the reference time K.

On the other hand, when the operation time of the off-cycle defrosting operation does not reach the reference time K, the control unit 30 controls the condenser fan 25 to start rotating after the off-cycle defrosting operation is terminated. When the off-cycle defrosting operation is terminated, the operation time of the off-cycle defrosting operation is determined, so the control unit 30 can rotate the condenser fan 25 between the end of the off-cycle defrosting operation and the resumption of the cooling operation based on the determined operation time of the off-cycle defrosting operation. In other words, when the operation time of the off-cycle defrosting operation does not reach the reference time K, a condenser fan operation period (condenser fan rotation period) in which the condenser fan 25 rotates exists between the off-cycle defrosting operation period and the cooling operation period. At this time, the control unit 30 can adjust, for example, the operation time (rotation time) of the condenser fan 25 according to the operation time of the off-cycle defrosting operation, which can reduce power consumption and increase the certainty that the temperature of the condenser 21 or near the condenser 21 will be equivalent to the outside air temperature. Specifically, the control unit 30 acquires, as the outside air temperature, the temperature detected by the clogging temperature sensor 21A at a timing when a predetermined time J (e.g., 10 minutes) has elapsed since the condenser fan 25 was operated after the off-cycle defrosting operation was completed. The operation time (rotation time) of the condenser fan 25 operated after the off-cycle defrosting operation was completed is counted by a condenser fan operation timer 33 electrically connected to the control unit 30 as shown in FIG. 3. The condenser fan operation timer 33 counts (times) the operation time of the condenser fan 25 operated after the off-cycle defrosting operation was completed, and is provided, for example, on a control board constituting the control unit 30, similar to the defrost cycle timer 31 and the defrosting operation timer 32. The time counted by the condenser fan operation timer 33 may be stored in a memory of the control board and readable by the control unit 30. When the operation time of the condenser fan 25 counted by the condenser fan operation timer 33 reaches a predetermined time J, the control unit 30 stops the condenser fan 25 and acquires the temperature detected by the clogging temperature sensor 21A as the outside air temperature. As described above, during the period during which the condenser fan 25 rotates between the end of the off-cycle defrost operation and the restart of the cooling operation (condenser fan operation period), both the compressor 20 and the internal fan 23 are stopped and the refrigeration cycle is stopped. During this condenser fan operation period, the refrigeration cycle is stopped, causing a slight temperature rise in the cooler 22, but because the internal fan 23 is stopped, it is difficult for the heat near the cooler 22 to diffuse into the cabinet, and the rise in the internal temperature is suppressed.

Next, the off-cycle defrosting operation will be described using the timing charts in Fig. 4 and Fig. 5 and the flow chart in Fig. 6. In Fig. 4 and Fig. 5, the operating state of the compressor 20, the interior fan 23, and the condensation prevention heater 12A is indicated as ON, and the stopped state is indicated as OFF. Of these, the compressor 20 is an inverter-controlled type, so in Fig. 4 and Fig. 5, the rotation speed of the compressor 20 is indicated in multiple stages, and the higher the indicated level, the higher the rotation speed of the compressor 20. In Fig. 4 and Fig. 5, the operating state of the condenser fan 25 is indicated by eight operating speed stages from speed 0 to speed 7, and the stopped state is indicated as OFF. In Fig. 4 and Fig. 5, the defrost temperature sensor 29 indicates the transition of the detected temperature and also indicates the defrost end temperature te. Fig. 6 is a flow chart showing the control from the start of the off-cycle defrosting operation to the transition to the cooling operation.

When the time counted by the defrost cycle timer 31 after the cooling operation is started reaches the defrost cycle time Td, the control unit 30 judges whether to perform the heater defrost operation or the off-cycle defrost operation. If the off-cycle defrost operation is started as a result of the judgment, the control unit 30 starts the counting by the defrost operation timer 32, and operates the inside fan 23 while stopping the compressor 20, the condenser fan 25, and the defrost heater 27 as shown in Figs. 4 and 5. During the off-cycle defrost operation, the inside temperature gradually rises, and accordingly the temperature of the cooler 22 or the vicinity of the cooler 22 (the temperature detected by the defrost temperature sensor 29) gradually rises and the melting of the frost attached to the cooler 22 progresses. When the off-cycle defrost operation is started, the control unit 30 judges whether the temperature detected by the defrost temperature sensor 29 is equal to or higher than the defrost end temperature te as shown in Fig. 6 (step S10). At this time, if the temperature detected by the defrost temperature sensor 29 is below the defrost end temperature te, the control unit 30 continues the off-cycle defrost operation. On the other hand, if the temperature detected by the defrost temperature sensor 29 is equal to or higher than the defrost end temperature te, the control unit 30 ends the off-cycle defrost operation (step S11).

Next, the control unit 30 judges whether the operation time of the off-cycle defrost operation counted by the defrost operation timer 32 is equal to or longer than the reference time K (step S12). At this time, if the operation time of the off-cycle defrost operation counted by the defrost operation timer 32 is equal to or longer than the reference time K, the control unit 30 acquires the temperature detected by the clogging temperature sensor 21A as the outside air temperature, as shown in FIG. 4 and FIG. 6 (step S13). After that, the control unit 30 starts (resumes) the cooling operation (step S16). In this way, when the operation time of the off-cycle defrost operation is equal to or longer than the reference time K, the control unit 30 performs the cooling operation immediately after the off-cycle defrost operation is terminated, and does not rotate the condenser fan 25 with the compressor 20 (refrigeration cycle) and the interior fan 23 stopped before performing the cooling operation. Note that when the control unit 30 starts the cooling operation, it operates the compressor 20, the condenser fan 25, and the interior fan 23, but keeps the defrost heater 27 stopped.

On the other hand, if the operation time of the off-cycle defrost operation counted by the defrost operation timer 32 does not reach the reference time K, the control unit 30 starts the operation of the condenser fan 25 and starts counting by the condenser fan operation timer 33, as shown in Figures 5 and 6 (step S14). At this time, the control unit 30 sets the operation speed of the condenser fan 25 to, for example, second speed. Of course, the operation speed of the condenser fan 25 at this time can be changed to a speed other than second speed. In addition, while the condenser fan 25 is rotating (condenser fan operation period), the control unit 30 stops both the compressor 20 (refrigeration cycle) and the interior fan 23. Then, the control unit 30 judges whether the operation time of the condenser fan 25 counted by the condenser fan operation timer 33 has passed the predetermined time J (step S15). If the operation time of the condenser fan 25 has not passed the predetermined time J, the process returns to step S15. If the operation time of the condenser fan 25 has exceeded the predetermined time J, the process proceeds to step S13, and the temperature detected by the clogging temperature sensor 21A is acquired as the outside air temperature. After that, the control unit 30 starts (resumes) the cooling operation (step S16). During the off-cycle defrosting operation and the cooling operation, the control unit 30 controls the dew prevention heater 12A to periodically repeat activation and deactivation, as shown in FIG. 4 and FIG. 5.

As described above, the cooling storage facility 10 of this embodiment includes a storage facility main body 11 having a storage chamber 12, a cooler (evaporator) 22 that constitutes a refrigeration cycle and cools the air in the storage chamber 12, a condenser 21 that constitutes a refrigeration cycle together with the cooler 22, a condenser fan 25 that blows air to the condenser 21, a clogging temperature sensor (sensor) 21A that detects the temperature of the condenser 21 or near the condenser 21, and a control unit 30 that controls the refrigeration cycle to perform a cooling operation and also performs a defrosting operation to melt frost that has adhered to the cooler 22. , the control unit 30 stops the condenser fan 25 during the defrosting operation, rotates the condenser fan 25 between the end of the defrosting operation and the restart of the cooling operation if the operation time of the defrosting operation does not reach the reference time K, controls the condenser fan 25 so that the load is lighter than when the operation time of the defrosting operation is equal to or longer than the reference time K between the end of the defrosting operation and the restart of the cooling operation does not reach the reference time K, and obtains the temperature detected by the clogging temperature sensor 21A after the defrosting operation is completed as the outside air temperature.

When the cooling operation is performed by the control unit 30, the refrigeration cycle is controlled, and the air inside the storage unit is cooled by the cooler 22. The condenser 21 is cooled by blowing air by the condenser fan 25. When the defrosting operation is performed by the control unit 30, the frost attached to the cooler 22 is melted. The condenser fan 25 is stopped by the control unit 30 during the defrosting operation. If the operation time of the defrosting operation does not reach the reference time K, the condenser fan 25 is rotated by the control unit 30 between the end of the defrosting operation and the restart of the cooling operation. At this time, the condenser fan 25 is controlled by the control unit 30 so that the load is heavier than when the operation time of the defrosting operation is equal to or greater than the reference time K. If the operation time of the defrosting operation does not reach the reference time K, it is assumed that the temperature of the condenser 21 or the vicinity of the condenser 21 has not been sufficiently reduced. In this case, if the condenser fan 25 is controlled by the control unit 30 so that the load is heavier, the temperature of the condenser 21 or the vicinity of the condenser 21 can be sufficiently reduced. This allows the temperature of the condenser 21 or the vicinity of the condenser 21 detected by the clogging temperature sensor 21A after the defrosting operation for an operation time less than the reference time to be completed to be equivalent to the outdoor air temperature. On the other hand, when the operation time of the defrosting operation is equal to or longer than the reference time K, the condenser fan 25 is controlled by the control unit 30 so that the load is lighter than when the operation time of the defrosting operation is less than the reference time K between the end of the defrosting operation and the restart of the cooling operation. If the operation time of the defrosting operation is equal to or longer than the reference time K, it is assumed that the temperature of the condenser 21 or the vicinity of the condenser 21 has sufficiently decreased to be close to the outdoor air temperature. In this case, even if the control unit 30 controls the condenser fan 25 to reduce the load, it is highly certain that the temperature of the condenser 21 or the vicinity of the condenser 21 detected by the clogging temperature sensor 21A after the defrosting operation for an operation time equal to or longer than the reference time is completed to be equivalent to the outdoor air temperature. Compared to the conventional case in which the condenser fan 25 is rotated for a fixed time regardless of the operation time of the defrosting operation, the amount of power consumption required to rotate the condenser fan 25 can be reduced. Moreover, the control unit 30 can obtain the temperature of the condenser 21 or the vicinity of the condenser 21 detected by the clogging temperature sensor 21A after the defrosting operation is completed as the outside air temperature, regardless of whether the operation time of the defrosting operation is equal to or longer than the reference time K. Therefore, compared to the conventional method of obtaining the outside air temperature after the defrosting operation is completed or during the defrosting operation, the control related to obtaining the outside air temperature is simplified. Also, a dedicated sensor for obtaining the outside air temperature is not required.

In addition, when the operation time of the defrosting operation is equal to or longer than the reference time K, the control unit 30 does not rotate the condenser fan 25 between the end of the defrosting operation and the restart of the cooling operation, whereas when the operation time of the defrosting operation is shorter than the reference time K, the control unit 30 controls the condenser fan 25 to rotate between the end of the defrosting operation and the restart of the cooling operation. In this way, when the operation time of the defrosting operation is equal to or longer than the reference time K, the control unit 30 does not rotate the condenser fan 25 between the end of the defrosting operation and the restart of the cooling operation, so that the load on the condenser fan 25 is lighter than when the operation time of the defrosting operation is shorter than the reference time K. Therefore, it is possible to achieve even lower power consumption than when the control unit 30 rotates the condenser fan 25 between the end of the defrosting operation and the restart of the cooling operation when the operation time of the defrosting operation is equal to or longer than the reference time K.

In addition, if the operation time of the defrosting operation does not reach the reference time K, the control unit 30 controls the condenser fan 25 to start rotating with the refrigeration cycle stopped after the defrosting operation is ended and before the cooling operation is restarted. When the defrosting operation is ended, the operation time of the defrosting operation is determined. If the determined operation time of the defrosting operation does not reach the reference time K, the control unit 30 can rotate the condenser fan 25 only as much as necessary according to the operation time of the defrosting operation between the end of the defrosting operation and the restart of the cooling operation. This makes it possible to further reduce power consumption and increases the certainty that the temperature of the condenser 21 or near the condenser 21 will be equivalent to the outside air temperature.

The storage unit 11 is also provided with an internal fan 23 for circulating air inside the storage unit, and the control unit 30 performs off-cycle defrosting as a defrosting operation by stopping the operation of the refrigeration cycle and rotating the internal fan 23. The operating time of off-cycle defrosting tends to be longer than when a heater defrosting operation using a defrost heater for heating the cooler 22 is performed as a defrosting operation. Therefore, when off-cycle defrosting is performed as a defrosting operation, there are many cases where the operating time is equal to or longer than the reference time K. In such cases, even if the load on the condenser fan 25 is reduced, the temperature of the condenser 21 or the vicinity of the condenser 21 is likely to be equal to the outside air temperature. In this way, if the load on the condenser fan 25 is reduced more frequently, it is favorable for achieving low power consumption.

<Embodiment 2>
A second embodiment will be described with reference to Fig. 7 to Fig. 9. In this second embodiment, the control relating to the off-cycle defrosting operation is modified. Note that the same structure, action, and effect as those of the first embodiment will not be described again.

The control unit according to this embodiment uses two reference times K1 and K2 as the reference time for determining the operation time of the off-cycle defrosting operation. In detail, the control unit determines the length of the operation time of the off-cycle defrosting operation based on the first reference time K1 (e.g., 30 minutes) and the second reference time K2 (e.g., 15 minutes) that is shorter than the first reference time K1 as the reference time, and controls the condenser fan. The off-cycle defrosting operation will be described below using the timing charts of Figures 7 to 9. Figure 7 is a timing chart showing a case where the operation time of the off-cycle defrosting operation is equal to or longer than the first reference time K1. Figure 8 is a timing chart showing a case where the operation time of the off-cycle defrosting operation is equal to or longer than the second reference time K2 and does not reach the first reference time K1. Figure 9 is a timing chart showing a case where the operation time of the off-cycle defrosting operation is equal to or longer than the second reference time K2 and does not reach the first reference time K1.

As shown in FIG. 7, when the operation time of the off-cycle defrosting operation is equal to or longer than the first reference time K1, the control unit performs the cooling operation immediately after the off-cycle defrosting operation is terminated, and does not rotate the condenser fan with the compressor (refrigeration cycle) and the interior fan stopped before resuming the cooling operation. In other words, when the operation time of the off-cycle defrosting operation is equal to or longer than the first reference time K1, there is no condenser fan operation period during which the condenser fan rotates between the off-cycle defrosting operation period and the cooling operation period. In this case, the load on the condenser fan is lighter than when the operation time of the off-cycle defrosting operation does not reach the first reference time K1. In contrast, as shown in FIG. 8 and FIG. 9, when the operation time of the off-cycle defrosting operation does not reach the first reference time K1, the control unit rotates the condenser fan with the compressor (refrigeration cycle) and the interior fan stopped before resuming the cooling operation. In other words, when the operation time of the off-cycle defrosting operation does not reach the first reference time K1, there is a condenser fan operation period during which the condenser fan rotates between the off-cycle defrosting operation period and the cooling operation period. During this condenser fan operation period, when controlling the condenser fan, the control unit varies the operation time of the condenser fan based on whether the operation time of the off-cycle defrost operation is equal to or longer than the second reference time K2. In detail, as shown in FIG. 8, when the operation time of the off-cycle defrost operation is equal to or longer than the second reference time K2 and does not reach the first reference time K1, the control unit operates the condenser fan for a first time J1 (e.g., 3 minutes) before resuming the cooling operation. In this case, the load on the condenser fan is heavier than when the operation time of the off-cycle defrost operation is equal to or longer than the first reference time K1, but is lighter than when the operation time of the off-cycle defrost operation does not reach the second reference time K2. On the other hand, as shown in FIG. 9, when the operation time of the off-cycle defrost operation does not reach the second reference time K2, the control unit operates the condenser fan for a second time J2 (e.g., 10 minutes) longer than the first time J1 before resuming the cooling operation. In this case, the load on the condenser fan is the heaviest.

As described above, during the condenser fan operation period when the operation time of the off-cycle defrost operation does not reach the first reference time K1, if the operation time of the off-cycle defrost operation is long, the control unit shortens the operation time of the condenser fan to reduce the load on the condenser fan, and if the operation time of the off-cycle defrost operation is short, the control unit lengthens the operation time of the condenser fan to increase the load on the condenser fan. In other words, it can be said that the control unit controls the load on the condenser fan during the condenser fan operation period more finely than in the above-mentioned embodiment 1 depending on the length of the operation time of the off-cycle defrost operation. This appropriately reduces power consumption and increases the certainty that the temperature of the condenser or near the condenser will be equivalent to the outside air temperature.

As described above, according to this embodiment, the control unit controls the condenser fan using a first reference time K1 and a second reference time K2 that is shorter than the first reference time K1 as reference times, and the control unit controls the condenser fan so that if the operating time of the defrosting operation is equal to or longer than the first reference time K1, the condenser fan is not rotated between the end of the defrosting operation and the restart of the cooling operation, and if the operating time of the defrosting operation is equal to or longer than the second reference time K2 and does not reach the first reference time K1, the condenser fan is rotated for a first time J1 between the end of the defrosting operation and the restart of the cooling operation, and if the operating time of the defrosting operation is shorter than the second reference time K2, the condenser fan is rotated for a second time J2 that is longer than the first time J1 between the end of the defrosting operation and the restart of the cooling operation. When the operation time of the defrosting operation is equal to or longer than the first reference time K1, which is longer than the second reference time K2, the control unit does not rotate the condenser fan between the end of the defrosting operation and the restart of the cooling operation, so the load on the condenser fan is lighter than when the operation time of the defrosting operation is shorter than the first reference time K1. When the operation time of the defrosting operation is equal to or longer than the second reference time K2 and shorter than the first reference time K1, the control unit rotates the condenser fan for the first time J1, which is shorter than the second time J2, between the end of the defrosting operation and the restart of the cooling operation, so the load on the condenser fan is heavier than when the operation time of the defrosting operation is equal to or longer than the first reference time K1, but is lighter than when the operation time of the defrosting operation is shorter than the second reference time K2. If the operation time of the defrosting operation is less than the second reference time K2, the control unit rotates the condenser fan for the second time J2, which is longer than the first time J1, between the end of the defrosting operation and the restart of the cooling operation, so the load on the condenser fan is the heaviest compared to when the operation time of the defrosting operation is equal to or longer than the second reference time K2. As described above, the load on the condenser fan is more precisely controlled by the control unit depending on the length of the operation time of the defrosting operation, so that power consumption is appropriately reduced and it is more certain that the temperature of the condenser or near the condenser will be equivalent to the outside air temperature.

<Embodiment 3>
A third embodiment will be described with reference to Fig. 10 or 11. In this third embodiment, the control relating to the off-cycle defrosting operation is changed from that in the first embodiment. Note that a duplicated description of the structure, action, and effect similar to those in the first embodiment will be omitted.

The control unit according to this embodiment rotates the condenser fan before resuming the cooling operation, regardless of whether the operation time of the off-cycle defrosting operation is equal to or longer than the reference time K. In other words, even if the operation time of the off-cycle defrosting operation is equal to or longer than the reference time K, a condenser fan operation period in which the condenser fan is rotated exists between the off-cycle defrosting operation period and the cooling operation period. Then, the control unit sets the operation time of the condenser fan in the condenser fan operation period to either a first time J1 (e.g., 3 minutes) or a second time J2 (e.g., 10 minutes) longer than the first time J1, depending on the length of the operation time of the off-cycle defrosting operation. The off-cycle defrosting operation will be described below using the timing charts of FIG. 10 and FIG. 11. FIG. 10 is a timing chart showing a case where the operation time of the condenser fan is the first time J1. FIG. 11 is a timing chart showing a case where the operation time of the condenser fan is the second time J2.

As shown in FIG. 10, when the operation time of the off-cycle defrost operation is equal to or longer than the reference time K, the control unit operates the condenser fan for a first time J1 before resuming the cooling operation. In this case, the load on the condenser fan is lighter than when the operation time of the off-cycle defrost operation does not reach the reference time K. On the other hand, as shown in FIG. 11, when the operation time of the off-cycle defrost operation does not reach the reference time K, the control unit operates the condenser fan for a second time J2 longer than the first time J1 before resuming the cooling operation. In this case, the load on the condenser fan is heavier than when the operation time of the off-cycle defrost operation is equal to or longer than the reference time K. In this way, it can be said that the control unit controls the load on the condenser fan during the condenser fan operation period according to the length of the operation time of the off-cycle defrost operation more finely than in the above-mentioned embodiment 1. This appropriately reduces power consumption and increases the certainty that the temperature of the condenser or near the condenser becomes equal to the outside air temperature.

As described above, according to this embodiment, if the operation time of the defrosting operation is equal to or longer than the reference time K, the control unit controls the condenser fan to rotate for the first time J1 between the end of the defrosting operation and the restart of the cooling operation, whereas if the operation time of the defrosting operation is less than the reference time K, the control unit controls the condenser fan to rotate for the second time J2 longer than the first time J1 between the end of the defrosting operation and the restart of the cooling operation. In this way, if the operation time of the defrosting operation is equal to or longer than the reference time K, the control unit rotates the condenser fan for the first time J1 shorter than the second time J2 between the end of the defrosting operation and the restart of the cooling operation, so that the load on the condenser fan is lighter than when the operation time of the defrosting operation is less than the reference time K. Therefore, if the operation time of the defrosting operation is equal to or longer than the reference time K, the temperature of the condenser or near the condenser is more likely to be equivalent to the outside air temperature than if the control unit does not rotate the condenser fan between the end of the defrosting operation and the restart of the cooling operation.

<Embodiment 4>
A fourth embodiment will be described with reference to Fig. 12 or 13. In this fourth embodiment, the control related to the defrosting operation is changed from that in the first embodiment. Note that a duplicated description of the structure, action, and effect similar to those in the first embodiment will be omitted.

The cooling storage according to this embodiment has both a refrigerator compartment in which stored items are refrigerated and a freezer compartment in which stored items are frozen. The refrigerator compartment has a lower internal temperature than the refrigerator compartment. In order to accommodate the difference in internal temperature, the refrigeration cycle of the cooling storage includes a cooler for the refrigerator compartment and a cooler for the freezer compartment. There is one compressor. The cooler for the freezer compartment is more susceptible to frosting than the cooler for the refrigerator compartment due to the lower internal temperature of the freezer compartment, and the amount of frost tends to be large. For this reason, in the freezer compartment, a heater defrosting operation is performed that can efficiently melt a large amount of frost that has adhered to the cooler for the freezer compartment in a short time, and an off-cycle defrosting operation is not performed. In contrast, in the refrigerator compartment, the amount of frost on the cooler for the refrigerator compartment differs depending on the usage situation, so either the heater defrosting operation or the off-cycle defrosting operation is appropriately performed depending on the conditions.

The defrosting operation (heater defrosting operation) performed in the freezer will be described with reference to FIG. 12. FIG. 12 is a flow chart showing the control related to the defrosting operation performed in the freezer. When the cooling operation is started, the control unit causes the defrosting cycle timer to start counting as shown in FIG. 12 (step S20). The control unit judges whether the time counted by the defrosting cycle timer has reached the defrosting cycle time Td (for example, 6 hours) (step S21). If the judgment result is YES, the control unit starts the heater defrosting operation (step S22). When the heater defrosting operation is started, the control unit judges whether the temperature detected by the defrosting temperature sensor has reached the defrosting end temperature te or higher (step S23). At this time, if the temperature detected by the defrosting temperature sensor is lower than the defrosting end temperature te, the control unit continues the heater defrosting operation. On the other hand, if the temperature detected by the defrosting temperature sensor has reached the defrosting end temperature te or higher, the control unit ends the heater defrosting operation (step S24).

Next, the defrosting operation performed in the refrigerator compartment will be described with reference to FIG. 13. FIG. 13 is a flowchart showing the control of the defrosting operation performed in the refrigerator compartment. When the cooling operation is started, the control unit starts counting the defrosting cycle timer as shown in FIG. 13 (step S30). The control unit judges whether the time counted by the defrosting cycle timer has reached the defrosting cycle time Td (step S31). If the judgment result is YES, the control unit judges whether the set temperature inside the refrigerator is equal to or higher than the set reference temperature ts (e.g., 2°C) (first condition) and whether the outside air temperature is equal to or higher than the reference outside air temperature tex (e.g., 20°C) (second condition) (step S32). If the judgment results for both the first and second conditions are YES, the control unit starts the off-cycle defrosting operation (step S33). On the other hand, if the judgment results for at least one of the first and second conditions are NO, the control unit starts the heater defrosting operation (step S34). When the heater defrost operation is started, the control unit determines whether the temperature detected by the defrost temperature sensor is equal to or higher than the defrost end temperature te (step S35). At this time, if the temperature detected by the defrost temperature sensor is lower than the defrost end temperature te, the control unit continues the heater defrost operation. On the other hand, if the temperature detected by the defrost temperature sensor is equal to or higher than the defrost end temperature te, the control unit ends the heater defrost operation (step S36). After that, the control unit starts the cooling operation and starts counting the defrost cycle timer (step S30).

When the off-cycle defrosting operation is started in step S33, the control unit starts counting the defrosting cycle timer (step S37). Then, the control unit judges whether the temperature detected by the defrosting temperature sensor is equal to or higher than the defrosting end temperature te (step S38). At this time, if the temperature detected by the defrosting temperature sensor is equal to or higher than the defrosting end temperature te, the control unit terminates the off-cycle defrosting operation (step S39). After that, the control unit judges whether the time counted by the defrosting cycle timer has reached the defrosting cycle time Td (step S31). On the other hand, if the temperature detected by the defrosting temperature sensor is less than the defrosting end temperature te in step S38, the control unit judges whether the time counted by the defrosting cycle timer has reached the defrosting cycle time Td (step S40). If the judgment result is NO, the process returns to step S38, and the control unit judges whether the temperature detected by the defrosting temperature sensor is equal to or higher than the defrosting end temperature te. On the other hand, if the determination result in step S40 is YES, the process proceeds to step S34, and the control unit starts a heater defrosting operation in the refrigerator compartment.

As described above, in the refrigerator compartment, when it is assumed that the amount of frost on the cooling device for the refrigerator compartment is large, a heater defrost operation is performed, whereas when it is assumed that the amount of frost on the cooling device for the refrigerator compartment is small, an off-cycle defrost operation is performed. Compared to the heater defrost operation, the off-cycle defrost operation does not energize the defrost heater and also suppresses the rise in the temperature inside the refrigerator compartment, so that it is possible to reduce power consumption and suppress the deterioration of stored items inside the refrigerator compartment. On the other hand, the off-cycle defrost operation in the refrigerator compartment may be performed for a long period of time, in which case there is a concern that the temperature inside the refrigerator compartment will continue to rise, albeit slowly, as the refrigeration cycle continues to be stopped. In this regard, according to the flowchart shown in FIG. 13, if the off-cycle defrost operation does not end even when the time counted by the defrost cycle timer after the start of the off-cycle defrost operation reaches the defrost cycle time Td, the control unit forcibly switches the defrost operation to the heater defrost operation. In this way, the frost that has adhered to the refrigerator compartment cooler is melted in a short time by the heater defrost operation, so the defrost operation can be terminated early and the refrigerator compartment can be switched to cooling operation. This makes it possible to suppress the rise in the temperature inside the refrigerator compartment that would otherwise occur if the off-cycle defrost operation were to continue for a long period of time.

<Embodiment 5>
A fifth embodiment will be described with reference to Fig. 14 to Fig. 16. In the fifth embodiment, the control related to the defrosting operation is changed from that in the fourth embodiment. Note that the description of the same structure, action, and effect as those in the fourth embodiment will be omitted.

As shown in FIG. 14, the cooling storage according to this embodiment includes a first elapsed time timer (elapsed time timer) 34 that counts the time that has elapsed since the heater defrosting operation ended in the freezer compartment. The first elapsed time timer 34 is provided, for example, on a control board that constitutes the control unit 430. The time counted by the first elapsed time timer 34 may be stored in the memory of the control board and may be readable by the control unit 430.

The defrosting operation (heater defrosting operation) performed in the freezer compartment will be described with reference to FIG. 15. FIG. 15 is a flowchart showing the control related to the defrosting operation performed in the freezer compartment. Steps S50 to S54 described in FIG. 15 are the same as steps S20 to S24 described in FIG. 12 in the fourth embodiment, and therefore redundant description will be omitted. When the heater defrosting operation is ended (step S54), the control unit 430 causes the first elapsed time timer 34 to start counting the elapsed time since the heater defrosting operation in the freezer compartment was ended (step S55).

Next, the defrosting operation performed in the refrigerator compartment will be described with reference to FIG. 16. FIG. 16 is a flowchart showing the control related to the defrosting operation performed in the refrigerator compartment. The flowchart in FIG. 16 differs from the flowchart in FIG. 13 described in the fourth embodiment mainly in that step S37 has been deleted and the content of step S40 has been changed. Steps S60 to S66 described in FIG. 16 are the same as steps S30 to S36 described in FIG. 13 described in the fourth embodiment, and therefore duplicated explanations will be omitted. Below, the differences between FIG. 16 and FIG. 13 will be described.

When the off-cycle defrosting operation is started in step S63, the control unit judges whether the temperature detected by the defrosting temperature sensor is equal to or higher than the defrosting end temperature te (step S67). At this time, if the temperature detected by the defrosting temperature sensor is equal to or higher than the defrosting end temperature te, the control unit terminates the off-cycle defrosting operation (step S68). After that, the control unit starts the cooling operation and starts counting the defrosting cycle timer (step S60). On the other hand, if the temperature detected by the defrosting temperature sensor is lower than the defrosting end temperature te in step S67, the control unit judges whether the elapsed time counted by the first elapsed time timer 34 (the elapsed time since the heater defrosting operation in the freezer compartment was terminated) has reached a predetermined time L (for example, 30 minutes) (step S69). If the judgment result is NO, the process returns to step S67, and the control unit judges whether the temperature detected by the defrosting temperature sensor is equal to or higher than the defrosting end temperature te. On the other hand, if the determination result in step S69 is YES, the process proceeds to step S64, and the control unit starts a heater defrosting operation in the refrigerator compartment.

As described above, if the off-cycle defrosting operation in the refrigerator compartment does not end even when the elapsed time counted by the first elapsed time timer 34 after the heater defrosting operation in the freezer compartment ends reaches the predetermined time L, the control unit forcibly switches the defrosting operation in the refrigerator compartment to the heater defrosting operation. In this way, the frost attached to the cooler for the refrigerator compartment is melted in a short time by the heater defrosting operation, so that the defrosting operation can be ended and the cooling operation can be started even earlier than in the fourth embodiment. This makes it possible to suppress the rise in the temperature inside the refrigerator compartment due to the prolonged off-cycle defrosting operation. Note that the operation time of the heater defrosting operation is, for example, about 10 to 30 minutes, which is almost always shorter than the operation time of the off-cycle defrosting operation. Therefore, if the heater defrosting operation in the freezer compartment and the off-cycle defrosting operation in the refrigerator compartment start at the same time, the heater defrosting operation in the freezer compartment is likely to end first. Therefore, the off-cycle defrost operation in the refrigerator compartment will be performed for at least the time (e.g., about 40 to 60 minutes) that is the sum of the operation time of the heater defrost operation in the freezer compartment and the predetermined time L that is the criterion for judgment in step S69. For this reason, if the amount of frost on the cooler for the refrigerator compartment is small, the off-cycle defrost operation performed in the refrigerator compartment may end before switching to the heater defrost operation. In this case, the heater defrost operation will not be performed in the refrigerator compartment, which is advantageous in terms of reducing power consumption, etc.

<Embodiment 6>
A sixth embodiment will be described with reference to Fig. 17 to Fig. 20. In this sixth embodiment, a function for detecting an abnormality in the pressure of the condenser is added. Note that a duplicated description of the structure, operation, and effect similar to those of the first embodiment will be omitted.

As shown in FIG. 17, the cooling storage according to this embodiment has a function of detecting a pressure abnormality in the condenser based on the temperature of the condenser or the vicinity of the condenser detected by the clogging temperature sensor 521A. In detail, if some abnormality occurs in the condenser that is operated in conjunction with the operation of the refrigeration cycle, the internal pressure of the condenser may become high pressure, which may cause a breakdown or the like. If the internal pressure of the condenser becomes high pressure, the temperature of the condenser or the vicinity of the condenser becomes high temperature, so if the detected temperature of the clogging temperature sensor 521A is monitored, a pressure abnormality (high pressure) in the condenser can be detected. For this reason, the control unit 530 monitors the detected temperature of the clogging temperature sensor 521A during the cooling operation, and when the detected temperature of the clogging temperature sensor 521A reaches a predetermined pressure abnormality detection temperature tp1 (for example, 65°C), the compressor 520 is stopped. In order to monitor the temperature detected by the clogging temperature sensor 521A, the control unit 530 is electrically connected to a second elapsed time timer 35 that counts the time elapsed since the temperature detected by the clogging temperature sensor 521A reaches the pressure abnormality detection temperature tp1. Below, the detection of a pressure abnormality in the condenser using the second elapsed time timer 35 will be explained using the timing chart in FIG. 18.

As shown in FIG. 18, when the temperature detected by the clogging temperature sensor 521A reaches the pressure abnormality detection temperature tp1 during cooling operation, the control unit 530 starts counting by the second elapsed time timer 35, and when the counted elapsed time reaches a predetermined time M (e.g., 60 minutes), the control unit 530 stops counting by the second elapsed time timer 35. The control unit 530 counts the number of times that the temperature detected by the clogging temperature sensor 521A reaches the pressure abnormality detection temperature tp1 until the elapsed time counted by the second elapsed time timer 35 reaches the predetermined time M. Then, when the number of times that the temperature detected by the clogging temperature sensor 521A reaches the pressure abnormality detection temperature tp1 (indicated as "number of high pressure detections" in FIG. 18) reaches a reference number (e.g., 5 times), the control unit 530 causes the display unit, which can display various information, to display an error. By causing the display unit to display an error, it is possible to inform the user that a pressure abnormality has occurred in the condenser, and to encourage maintenance, repair, etc. In addition, the control unit 530 resumes the operation of the compressor 520 when the temperature detected by the clogging temperature sensor 521A falls to a predetermined release temperature tp2 after reaching the pressure abnormality detection temperature tp1. The release temperature tp2 is, for example, "pressure abnormality detection temperature tp1-10K". Therefore, when the temperature detected by the clogging temperature sensor 521A goes back and forth between the pressure abnormality detection temperature tp1 and the release temperature tp2, the control unit 530 repeatedly stops and resumes the operation of the compressor 520 (FIG. 18 illustrates a case where the temperature is repeated about every 5 minutes). The pressure abnormality detection temperature tp1 has an initial value of, for example, 65°C, but can be changed as appropriate by the user. When the pressure abnormality detection temperature tp1 is the initial value (65°C), the release temperature tp2 is "initial value-10K", for example, 55°C.

However, for example, if the clogging temperature sensor 521A fails, the temperature detected by the clogging temperature sensor 521A that has reached the pressure abnormality detection temperature tp1 may not drop to the release temperature tp2, or it may take a long time to drop to the release temperature tp2. In such cases, problems may occur, such as the condenser pressure abnormality not being detected properly.

Therefore, as shown in FIG. 17, the control unit 530 is electrically connected to a third elapsed time timer 36 that counts the time elapsed since the temperature detected by the clogging temperature sensor 521A reaches the pressure abnormality detection temperature tp1. When the temperature detected by the clogging temperature sensor 521A reaches the pressure abnormality detection temperature tp1 during cooling operation, the control unit 530 starts counting by the third elapsed time timer 36, and when the temperature detected by the clogging temperature sensor 521A reaches the release temperature tp2, the control unit 530 stops counting by the third elapsed time timer 36. Then, when the elapsed time counted by the third elapsed time timer 36 reaches a predetermined high pressure detection time N, the control unit 530 causes the display unit to display an error. This high pressure detection time N is set longer than the predetermined time M, which is the maximum elapsed time counted by the second elapsed time timer 35, and is specifically set to, for example, 70 minutes. Below, the pressure abnormality detection of the condenser using the second elapsed time timer 35 and the third elapsed time timer 36 will be described with reference to the timing charts of FIG. 19 and FIG. 20.

As shown in FIG. 19, when the temperature detected by the clogging temperature sensor 521A reaches the pressure abnormality detection temperature tp1 during cooling operation, the control unit 530 causes the second elapsed time timer 35 and the third elapsed time timer 36 to start counting the elapsed time. According to FIG. 19, even if the elapsed time counted by the second elapsed time timer 35 reaches the predetermined time M, the temperature detected by the clogging temperature sensor 521A does not reach the release temperature tp2. At this point, the number of times that the temperature detected by the clogging temperature sensor 521A reaches the pressure abnormality detection temperature tp1 (indicated as "high pressure detection number" in FIG. 19) is one, which does not meet the reference number, so the control unit 530 does not cause the display unit to display an error. According to FIG. 19, even if more time passes and the elapsed time counted by the third elapsed time timer 36 reaches the high pressure detection time N, the temperature detected by the clogging temperature sensor 521A does not reach the release temperature tp2. In this case, the control unit 530 causes the display unit to display an error when the elapsed time counted by the third elapsed time timer 36 reaches the high pressure detection time N.

As shown in FIG. 20, when the temperature detected by the clogging temperature sensor 521A reaches the pressure abnormality detection temperature tp1 during cooling operation, the control unit 530 causes the second elapsed time timer 35 and the third elapsed time timer 36 to start counting the elapsed time. According to FIG. 20, the temperature detected by the clogging temperature sensor 521A drops to the release temperature tp2 once, so at this point, the control unit 530 stops the counting by the third elapsed time timer 36. Note that at this point, the elapsed time counted by the third elapsed time timer 36 has not reached the high pressure detection time N. In addition, the counting by the second elapsed time timer 35 continues. After that, when the temperature detected by the clogging temperature sensor 521A rises again and reaches the pressure abnormality detection temperature tp1, the control unit 530 causes the third elapsed time timer 36 to resume counting the elapsed time. According to FIG. 20, even if the elapsed time counted by the second elapsed time timer 35 reaches the predetermined time M, the temperature detected by the clogging temperature sensor 521A does not reach the release temperature tp2. At this point, the number of times the temperature detected by the clogging temperature sensor 521A reaches the pressure abnormality detection temperature tp1 (indicated as "high pressure detection count" in FIG. 20) is two, which is less than the reference number, so the control unit 530 does not cause the display unit to display an error. According to FIG. 20, even if more time passes and the elapsed time counted by the third elapsed time timer 36 reaches the high pressure detection time N, the temperature detected by the clogging temperature sensor 521A does not reach the release temperature tp2. In this case, the control unit 530 causes the display unit to display an error when the elapsed time counted by the third elapsed time timer 36 reaches the high pressure detection time N.

As described above, the control unit 530 can display an error on the display unit based on the elapsed time counted by the third elapsed time timer 36 even if the number of high pressure detections does not reach the reference number. Therefore, for example, even if a failure occurs in the clogging temperature sensor 521A and the detected temperature of the clogging temperature sensor 521A that has reached the pressure abnormality detection temperature tp1 does not drop to the release temperature tp2 or takes a long time to drop to the release temperature tp2, the pressure abnormality of the condenser can be properly detected. Moreover, the control unit 530 also has a function of displaying an error on the display unit when the number of times that the detected temperature of the clogging temperature sensor 521A reaches the pressure abnormality detection temperature tp1 reaches the reference number before the elapsed time counted by the second elapsed time timer 35 reaches the predetermined time M, so that the pressure abnormality of the condenser can be more properly detected. In addition, because the high pressure detection time N is set to be longer than the predetermined time M, which is the maximum elapsed time counted by the second elapsed time timer 35, it is possible to prevent an error message caused by the counting of the third elapsed time timer 36 from being displayed on the display unit prior to an error message caused by the counting of the second elapsed time timer 35. This makes it difficult for error messages to be displayed frequently.

<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) When the operation time of the off-cycle defrosting operation is equal to or longer than the reference time K, the control unit 30, 430, 530 may control the condenser fan 25 to rotate at a first operation speed (first rotation speed) between the end of the defrosting operation and the restart of the cooling operation, whereas when the operation time of the off-cycle defrosting operation does not reach the reference time K, the control unit 30, 430, 530 may control the condenser fan 25 to rotate at a second operation speed (second rotation speed) that is faster than the first operation speed between the end of the defrosting operation and the restart of the cooling operation. In this way, when the operation time of the off-cycle defrosting operation is equal to or longer than the reference time K, the control unit 30, 430, 530 rotates the condenser fan 25 at a first operation speed that is slower than the second operation speed between the end of the defrosting operation and the restart of the cooling operation, so that the load on the condenser fan 25 is lighter than when the operation time of the off-cycle defrosting operation does not reach the reference time K. Therefore, if the operating time of the off-cycle defrost operation is equal to or longer than the reference time K, the temperature of the condenser 21 or near the condenser 21 is more likely to become equal to the outside air temperature than if the control unit 30, 430, 530 does not rotate the condenser fan 25 between the end of the defrost operation and the restart of the cooling operation.

(2) The control unit 30, 430, 530 may control the condenser fan 25 so that the load is lighter when the operation time of the heater defrost operation is equal to or longer than the reference time than when the time between the end of the defrost operation and the resumption of the cooling operation is less than the reference time.

(3) The specific values of the reference time K described in the first and third embodiments can be changed as appropriate to values other than 30 minutes. Similarly, the specific values of the first reference time K1 and the second reference time K2 described in the second embodiment can also be changed as appropriate.

(4) The specific value of the predetermined time J described in embodiment 1 can be changed appropriately to a value other than 10 minutes. Similarly, the specific values of the first time J1 and the second time J2 described in embodiments 2 and 3 can also be changed appropriately.

(5) The specific value of the defrost end temperature te described in the first, fourth, and fifth embodiments can be changed appropriately to a value other than 10°C. Similarly, the specific value of the interior set reference temperature ts described in the fourth and fifth embodiments can be changed appropriately to a value other than 2°C. Similarly, the specific value of the reference outdoor air temperature tex described in the fourth and fifth embodiments can be changed appropriately to a value other than 20°C. Furthermore, the specific value of the defrost cycle time Td described in the first and fourth embodiments can be changed appropriately to a value other than 6 hours. Furthermore, the specific value of the predetermined time L described in the fifth embodiment can be changed appropriately to a value other than 30 minutes.

(6) The specific values of the predetermined time M and high pressure detection time N described in embodiment 6 can be changed as appropriate. Similarly, the specific values of the pressure abnormality detection temperature tp1 and the release temperature tp2 can be changed as appropriate. Similarly, the reference number of times related to the number of high pressure detections can be changed as appropriate to a value other than five times.

(7) It is also possible to add an outside air temperature sensor (ambient temperature thermistor) to detect the outside air temperature (ambient temperature) of the cooling storage facility 10. In that case, it is also possible to omit the stop temperature sensor 21A, 521A.

(8) The compressor 20 may be a type other than inverter-controlled.

(9) A hot gas defrost method (an example of a heating defrost method) can also be used as the defrost method for the defrosting operation. In the hot gas defrost method, hot gas is supplied from the compressor 20 to the cooler 22 to heat the cooler 22 and melt the frost on the cooler 22. During the defrosting operation of the hot gas defrost method, no refrigerant is flowed through the condenser 21 and the condenser fan 25 is stopped, so that this technology can be applied.

(10) In addition to the cooling storage unit 10 having a freezer and a refrigerator, the present technology can also be applied to a cooling storage unit having a refrigerator but no freezer, and a cooling storage unit having a freezer but no refrigerator. The present technology can also be applied to a cooling storage unit that does not have a workbench 15.

10...cooling storage, 11...storage body, 12...storage room, 21...condenser, 21A, 521A...clogging temperature sensor (sensor), 22...cooler (evaporator), 23...interior fan, 25...condenser fan, 30, 430, 530...control unit, J1...first time, J2...second time, K...reference time, K1...first reference time, K2...second reference time

Claims (6)

A storage body having a storage chamber;
an evaporator that constitutes a refrigeration cycle and cools the air in the storage chamber;
a condenser which configures the refrigeration cycle together with the evaporator;
A condenser fan that blows air to the condenser;
a sensor for detecting a temperature of the condenser or a temperature in the vicinity of the condenser;
A control unit that controls the refrigeration cycle to perform a cooling operation and also performs a defrosting operation to melt frost adhering to the evaporator,
The control unit stops the condenser fan during the defrosting operation, and if the operating time of the defrosting operation does not reach a standard time, rotates the condenser fan between the end of the defrosting operation and the restart of the cooling operation, and if the operating time of the defrosting operation is equal to or longer than the standard time, controls the condenser fan so that the load is lighter than when the operating time between the end of the defrosting operation and the restart of the cooling operation does not reach the standard time, and obtains the temperature detected by the sensor after the defrosting operation is ended as the outside air temperature. The cooling storage facility according to claim 1, wherein the control unit controls the condenser fan so that the condenser fan is not rotated between the end of the defrosting operation and the restart of the cooling operation if the operation time of the defrosting operation is equal to or longer than the reference time, whereas the control unit controls the condenser fan so that the condenser fan is rotated between the end of the defrosting operation and the restart of the cooling operation if the operation time of the defrosting operation is shorter than the reference time. The cooling storage facility according to claim 2, wherein the control unit controls the condenser fan to start rotating in a state where the refrigeration cycle is stopped after the defrosting operation is terminated if the operation time of the defrosting operation does not reach the reference time. the control unit controls the condenser fan by using, as the reference time, a first reference time and a second reference time that is shorter than the first reference time,
2. The cooling storage facility according to claim 1, wherein the control unit controls the condenser fan so as not to rotate the condenser fan between the end of the defrosting operation and the restart of the cooling operation if the operating time of the defrosting operation is equal to or longer than the first reference time, to rotate the condenser fan for a first time between the end of the defrosting operation and the restart of the cooling operation if the operating time of the defrosting operation is equal to or longer than the second reference time and does not reach the first reference time, and to rotate the condenser fan for a second time longer than the first time between the end of the defrosting operation and the restart of the cooling operation if the operating time of the defrosting operation does not reach the second reference time. 2. The cooling storage facility according to claim 1, wherein the control unit controls the condenser fan to rotate for a first time between the end of the defrosting operation and the restart of the cooling operation if the operating time of the defrosting operation is equal to or longer than the reference time, and controls the condenser fan to rotate for a second time longer than the first time between the end of the defrosting operation and the restart of the cooling operation if the operating time of the defrosting operation is shorter than the reference time. The cooling storage facility according to any one of claims 1 to 5, further comprising an interior fan disposed within the storage body for circulating air within the storage facility, and the control unit performs off-cycle defrosting as the defrosting operation by stopping the operation of the refrigeration cycle and rotating the interior fan.

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