JP2951193B2 - Refrigerator defroster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defroster for a refrigerator that performs a defrosting operation of a cooler at a preset defrosting start timing.

[0002]

2. Description of the Related Art Conventionally, in a refrigerator, when a large amount of frost adheres to a cooler, the cooling efficiency is reduced. Therefore, when a predetermined defrost start timing is reached, power is supplied to a defrost heater. The defrosting operation is performed by heating the cooler.

[0003] In this case, conditions for the defrost start timing include those set as follows.

(1) When a predetermined time has elapsed since the previous defrosting operation.

(2) When the accumulated operation time of the compressor of the refrigeration cycle apparatus has reached a predetermined value since the previous defrosting operation (see FIG. 9 for a control flowchart).

(3) An optimum defrost start timing is estimated from the outside air temperature, the number of opening and closing doors, and the operating rate of the compressor.

[0007]

However, (1)
In general, the defrosting start timing is determined on the basis of the worst operating conditions with much frosting, so the actual situation is that the defrosting operation is actually performed with a small amount of frosting. , Energy efficiency is extremely poor.

Further, under the condition (2), the defrost start timing can be set according to the load condition of the cooler. However, since the integrated judgment value in this case is based on the entry and exit of food and the like, If the user is absent for a long time or for the purpose of long absence, and the door is left open and closed,
Despite the fact that the amount of frost is smaller than usual, defrosting is performed more than necessary, and energy efficiency deteriorates.

Further, under the condition (3), the optimum defrosting start timing can be set, but the amount of calculation for calculating the defrosting start timing increases, and the high-speed calculation and the high calculation accuracy as a refrigerator control device. There is a drawback that functions are required and the control device is complicated and expensive.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a refrigerator defrosting apparatus capable of defrosting a cooler at an appropriate timing while saving labor with a simple configuration. It is in.

[0011]

According to the present invention, a defrosting device for a refrigerator is provided with defrosting control means for executing a defrosting operation of a cooler at a preset defrosting start timing, and at least a previous defrosting operation is performed. A door open storage unit for storing that the door of the refrigerator is opened later is provided, and a forced operation storage for storing that the forced continuous operation of the compressor for the cooler has been executed at least after the previous defrosting operation. Means for detecting or estimating the ambient temperature of the refrigerator, and then providing the outside air temperature determination means, and setting the defrost control means to the door open storage means and the forced operation storage when the defrost start timing comes. When the means is in a non-stored state and the temperature detected or estimated by the outside air temperature determining means is within a predetermined temperature range, a first extension for delaying the defrost start timing by a certain time. And executes a work, and in the defrosting start timing at the time of the first extension operation end the door opening storing means and the forced operation storage means is a storage state
When the defrosting operation is not performed , the defrosting start timing is further deferred for a certain period of time, and a second extension operation is repeatedly performed.
When the operation has been performed a specified number of times or when the second extension operation is completed
At the defrosting start timing at the end of
And when the forcible operation storage means is in the storage state.
It is configured to execute a frost operation .

In this case, when the defrosting start timing is reached, the door opening storage means and the forced operation storage means are in the non-storage state and the temperature detected or estimated by the outside air temperature determination means is determined. When the temperature is within the predetermined temperature range, the defrosting start timing is advanced until the integrated operation time of the compressor reaches a predetermined time, and the defrosting at the end of the first extending operation is performed. Except when the door opening storage means and the forced operation storage means were in the storage state at the start timing.
When the frost operation is performed and the memory is in the non-memory state, the second extension operation of delaying the defrost start timing further until the integrated operation time of the compressor reaches a certain time is repeated.
And the second extension operation is performed a specified number of times.
When defrosting starts or when the second extension operation ends
The memory for opening the door and the forcible operation
When the storage unit is in the storage state, a defrosting operation may be performed.

[0013] The outside air temperature judging means may be configured to estimate the outside air temperature based on the operating rate of the compressor.

Further, the defrost control means comprises a defrost control device for executing an extension operation for delaying the defrost start timing, and detects a temperature of a predetermined storage space in which the defrost control device is stored. After the provision of the temperature sensor, the outside air temperature determining means may be configured to estimate the outside air temperature based on the temperature detected by the temperature sensor.

Further, the defrost control means may be configured such that, when a forced operation is performed during execution of the extension operation, the time measurement of the extension operation is interrupted until the forced operation ends.

[0016]

According to the first aspect of the present invention, when a preset defrost start timing comes, the defrost control means determines that the door opening storage means and the forced operation storage means are in the non-storage state and the outside air temperature. It is determined whether the determination temperature by the determination means is within a predetermined temperature range. At this time, if the door has not been opened and the forced operation has not been performed since the previous defrosting operation and the outside air temperature is within the predetermined temperature range, the defrosting control means needs to perform the defrosting operation. It is determined that there is no defrosting start timing, and a first extension operation for delaying the defrost start timing by a predetermined time is executed. Was necessary, a defrosting operation was necessary.
It is determined that there is no defrosting start timing, and a second extension operation of delaying the defrost start timing by a certain time is executed.

In this case, the defrost control means repeatedly executes the second extension operation, and executes the second extension operation for a prescribed number of times.
Defrosting after several executions or at the end of the second extension operation
At the start timing, the door opening storage means and the forcing
When the operation storage unit is in the storage state, a defrosting operation is performed. Therefore, when the condition that the defrosting operation is not required continues, the first extension operation is executed once and the second extension operation is executed a specified number of times, and the time when the execution of the specified number of the second extension operations ends The defrosting operation is executed.

If the defrosting condition is satisfied at the defrosting start timing, the defrosting control means determines that the defrosting operation is necessary, and executes the defrosting operation at the end of the execution of the extension operation. I do. Thus, the defrosting operation can be performed at an appropriate timing while performing the labor-saving operation.

In the case of the refrigerator defrosting device according to claim 2,
When executing the extension operation, the defrost control means delays the defrost start timing until the integrated operation time of the compressor reaches a certain time. Thereby, the defrost start timing can be set accurately.

[0020] In the case of the refrigerator defrosting device according to claim 3,
Since the outside air temperature determination means estimates the outside air temperature based on the operating rate of the compressor, a special temperature sensor for detecting the outside air temperature can be omitted.

In the case of the refrigerator defrosting device according to claim 4,
The outside air temperature determination unit estimates the outside air temperature based on the temperature detected by the temperature sensor that detects the temperature of the predetermined storage space in which the defrost control device as the defrost control unit is stored, so that the outside air temperature is detected. The lead wire of the temperature sensor need not be led out of the storage space.

In the case of the refrigerator defrosting device according to claim 5,
When the forced operation is performed during the execution of the extension operation, the defrost control means suspends the time measurement of the extension operation until the forced operation is completed. The problem of heating can be avoided.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 2 schematically shows wiring between various electric components provided in the refrigerator and a control device. In FIG. 2, a refrigerator room 1, a refrigerator room 3, and a vegetable room 4 are formed in the refrigerator main body 1 from above, and the respective rooms 2, 3, and 3 are formed.
Doors 5, 6 and 7 for closing 4 are provided. Door switches 8, 9, and 10 that are turned on when the doors 5, 6, and 7 are opened are attached to each of the chambers 2, 3, and 4. When those doors are turned on, the defrosting control means and the door are opened. Control device 11 as storage means, forced operation storage means and outside air temperature determination means
Outputs an ON signal. A forced operation button 12 and a monitor lamp 13 are arranged on the front surface of the door 5 of the freezer 2. A forced operation command is given to the control device 11 when the forced operation button 12 is on, and the control device is operated during the forced operation. 11 turns on the monitor lamp 13.

A cooler room 14 is formed at the back of the freezing room 2, and a cooler 15 and a defrost heater 16 are arranged in the cooler room 14. The defrost heater 16 is connected to the control device 1
The cooler 15 is heated according to the energization by step 1. A fan motor 17 is disposed above the cooler room 14, and the air purified in the cooler room 14 is sent to the freezing room 2 when the control device 11 drives the fan motor 17. The freezing compartment 2 is provided with a freezing temperature sensor 18, and the temperature detected by the freezing temperature sensor 18 (freezing temperature) is given to the control device 11.

A motor damper 20 is disposed at the cool air outlet 19 to the refrigerator compartment 3. The motor damper 20 closes the cool air outlet 19 and the open position for opening the cool air outlet 19 in response to the drive by the control device 11. It is controlled to the closed position. The refrigerator compartment 3 is provided with a refrigerator temperature sensor 21, and the temperature detected by the refrigerator temperature sensor 21 (refrigeration temperature) is given to the control device 11.

A compressor 23 is provided in the machine room 22, and a cooling medium is supplied to the cooler 15 in a state where the compressor 23 is driven by the control device 11, so that the cooler 15 is cooled.

The control device 11 is housed in a closed space (not shown) and includes a temperature sensor for detecting the temperature of the closed space, and executes the following control.

(1) The compressor 23 and the fan motor 17 are driven when the temperature of the freezing compartment 2 detected by the freezing temperature sensor 18 becomes -20 ° C. or more, and the compressor 23 and the fan motor 17 are stopped when the temperature becomes -24 ° C. or less. I do.

(2) When the temperature of the refrigerating compartment 3 detected by the refrigerating temperature sensor 21 becomes 5 ° C. or more, the motor damper 20 is controlled to the open position, and when the temperature becomes 3 ° C. or less, the motor damper 20 is controlled to the closed position.

(3) The operation time of the compressor 23 is integrated, and when the integrated operation time reaches a predetermined time, the defrosting operation of energizing the defrost heater 16 and heating the cooler 15 is basically performed. Will execute.

(4) When the forced operation button 12 is turned on,
The compressor 23 is forcibly driven to execute the forced operation until a fixed time (for example, 90 minutes) elapses or the forced operation button 12 is turned off , and the monitor lamp 13 is turned on during the execution of the forced operation.

(5) If the predetermined condition is satisfied at the defrost start timing in the above (3), an extension operation of postponing the defrost start timing by a predetermined time is executed.

Next, the operation of the above configuration will be described. FIG. 1 shows a flowchart of the operation of the control device 11. In this case, FIG. 1 shows only the control related to the present invention, and the ordinary refrigerator cooling control (compressor and damper control) related to the above (1) to (4) is omitted. That is,
In FIG. 3, the control device 11 first clears the door open flag and the forced operation flag (step S1), and then clears the integration timer (step S2). Then, in the normal cooling control (not shown), when it is determined that the door is opened based on the door switches 8 to 10, a door open flag is set (step S <b> 3), and the forced operation is performed by pressing the forced operation button 12. When executed, set the forced operation flag. During the ON period of the compressor 23, the integration timer is driven (steps S7 and S7).
8) During the OFF period, the integration timer is stopped (steps S7 and S9) to calculate the integrated operation time of the compressor 23. Then, when the integrated timer value reaches, for example, 10 hours (step S10), it is determined that the defrost start timing has come, and a first extension operation of delaying the defrost start timing by a predetermined time is executed by the following control. Determine whether or not.

When the door open flag is reset during the normal cooling control, that is, when the doors 5 to 7 are closed, the amount of frost adhering to the cooler 15 is small and the defrosting operation is postponed. This does not cause any problems. However,
When the doors 5 to 7 are opened, a large amount of outside air enters the refrigerator and a large amount of frost adheres to the cooler 15.
In this case, delaying the defrosting operation causes a problem. Similarly, even when the forced operation is performed during the normal cooling control, the amount of heat exchange of the cooler 15 increases and the deposition speed of the frost increases, so that the postponement of the defrost operation is hindered.

Therefore, the controller 11 sets the integration timer to 1
After the elapse of 0 hours, it is determined whether the door open flag or the forced operation flag is set (step S).
11) When any of the flags is set, it is determined that a condition that requires the defrosting operation has occurred, and the flag is cleared to be cleared before the defrosting operation is performed (steps S23 and S24). ).

When none of the flags is set, the outside air temperature is estimated based on the temperature detected by a temperature sensor (not shown), and whether the estimated outside air temperature is within a predetermined temperature range (for example, 20 ° C. to 30 ° C.). It is determined whether or not it is (step S12). At this time, if the estimated outside air temperature is out of the predetermined temperature range, the flag is cleared and the defrosting operation is performed (steps S23 and S24) (see FIG. 3). This is because when the outside air temperature is lower than the predetermined temperature range, the operation rate of the refrigerator is reduced and defrosting is not performed for a long period of time. This is because the frost adhering to 15 hardens and becomes icy, which is difficult to melt, and the cooling performance deteriorates, so that it is difficult to extend the defrosting operation. On the other hand, when the outside air temperature is higher than the predetermined temperature range, the operation rate of the compressor 23 increases, the amount of heat exchange (cooling amount) in the cooler 15 increases, and frost easily adheres to the cooler 15. However, also in this case, extending the defrosting operation causes a problem.

Here, the estimation of the outside air temperature as described above is as follows.
It can be obtained based on the relationship between the temperature of the storage space in which the control device 11 is stored by a temperature sensor (not shown) provided in the control device 11 and the outside air temperature checked in advance. That is, the temperature of such a storage space relatively changes under the influence of the outside air temperature.

Now, in the ordinary cooling control, the doors 5-7
When the closed state and the non-operation state of the forced operation button 12 continue and the estimated outside air temperature is within a predetermined temperature range,
The controller 11 determines that there is no need for the defrosting operation, clears the counter and starts the real-time timer (steps S13 and S14), and then continues for a predetermined time (for example, 10
The first extension operation is executed by continuing the cooling operation for (0 minutes) (step S19).

During the execution of the first extension operation, the control device 11 sets the door open flag when the doors 5 to 7 are opened (steps S15 and S16), and presses the forced operation button 12. At this time, the forced operation flag is set (steps S17, S18). Then, when such a first extension operation is completed, it is the defrost start timing, so that
The control device 11 determines whether any of the door open flag and the forced operation flag is set (Step S).
20) If the flag is set, it is determined that a condition that requires the defrosting operation has occurred, and the defrosting operation is performed (step S24). Here, at the defrost start timing at the end of the first extension operation, the estimation of the outside air temperature is not performed. This is because it is not sufficient to estimate the outside air temperature at the first defrosting start timing after the end of the defrosting operation, since the room temperature cannot change suddenly by several tens of degrees Celsius in a general home use environment. .

When the defrosting condition is not satisfied at the defrosting start timing at the end of the first extension operation, the control device 11 advances the defrosting start timing by a predetermined time (100 minutes). When the defrosting condition is not satisfied at the defrosting start timing at the end of the second extension operation, the second extension operation is repeatedly performed (step S2).
2). At this time, when the control device 11 determines that the defrosting operation is necessary based on the door opening flag and the forced operation flag at the defrosting start timing at the end of the second extension operation (step S20), the defrosting operation is performed. (See FIG. 4).

When the control device 11 has repeatedly executed the second extension operation, the counter value, that is, when the second extension operation has reached the specified number of times (steps S21 and S2).
2) It is determined that the defrost condition is satisfied, and the defrost operation is performed (see FIG. 5). In this case, as the prescribed number of times of the second extension operation, when the refrigerator is left unattended such that the closed state of the doors 5 to 7 and the non-execution state of the forced operation continue, the maximum effect is obtained in both the cooling performance and the power saving. It can be determined from the defrosting operation interval that can be exerted. That is, when the defrosting operation interval is set to, for example, 24 hours, the accumulated operation time of the compressor 23 during the normal cooling operation is 10 hours.
It is possible to set the defrosting operation interval to 24 hours or more by executing the extended operation time of 100 minutes three times (the first extended operation is performed once and the second extended operation is performed twice). Therefore, the prescribed number of executions of the second extension operation in this case is two. To convert the accumulated operating time of the compressor 23 into real time, the accumulated operating time of 10 hours is calculated from the operating rate of the compressor 23 under the condition that the outside air temperature is 20 ° C. to 30 ° C., which is the advance condition of the defrost start timing. Can be obtained in real time.

Here, in the present embodiment, the determination as to whether or not to postpone the defrosting start timing is made at the end of the extension operation. In a configuration in which the defrosting operation is immediately executed by opening the doors 5 to 7 or operating the forced operation button 12 during the extension operation, the doors 5 to 7 are opened to cool and preserve the food during the extension operation. This causes a problem that the defrosting operation is immediately executed and the food cannot be cooled and stored unless the defrosting operation is completed. Similarly, if the forced operation button 12 is operated to perform the forced operation during the extension operation, a problem occurs that the defrosting operation is immediately performed and the forced operation cannot be performed.

In the present embodiment, the flag used for determining whether or not to postpone the defrost start timing at the end of the extension operation is cleared at the time of executing the defrost operation. This is because when the doors 5 to 7 are opened and food is taken in and out during the defrosting operation, a large amount of moisture-containing air flows into the refrigerator and a large amount of frost enters the cooler 15 in the subsequent cooling operation. This is because it is necessary to check the opening and closing of the doors 5 to 7 even during the defrosting, because there is a possibility that they will adhere to the door.

According to the above configuration, when the condition that does not require the defrosting operation of the cooler 15 continues until the preset defrosting start timing, the first extension that delays the defrosting start timing by a predetermined time. When the operation is performed and the condition that does not require the defrosting operation continues until the defrosting start timing at the end of the extension operation, the second extension operation is further performed to execute the extension operation up to a specified number of times. Therefore, when the condition that does not require the defrost operation continues, the power consumption can be postponed as much as possible to save the power, and the condition that requires the defrost operation occurs once. In this case, the defrosting operation can be executed at the end timing of the normal cooling operation or the extension operation, so that the cooling performance of the cooler 15 can be maintained. Therefore, unlike the conventional example in which the defrosting operation is performed when a predetermined time has elapsed from the previous defrosting operation or when the cumulative operation time of the compressor has reached a predetermined value, the defrosting operation is performed at an appropriate timing. Thereby, energy efficiency can be improved. Further, unlike the function of estimating the defrost start timing, the control device 11 does not require a high-speed calculation and a high calculation accuracy function as a function of the control device 11.
Is not complicated and expensive.

As a specific numerical value of the power saving effect according to the present embodiment, in the case of a 400 liter class refrigerator, if the defrosting interval is set to 24 hours or more in real time, it becomes 2 per month.
When the power amount of KW is reduced and the defrosting interval is set to 72 hours or more in real time, the power amount of 4 to 5 KW per month can be reduced.

FIG. 6 shows a flowchart of the control device 11 according to the second embodiment of the present invention. The difference between the second embodiment and the first embodiment is that the advance time at the time of execution of the extension operation is determined by the integrated operation time of the compressor 23.

That is, when the control device 11 determines that the defrosting operation is not to be performed based on the flag when the defrost timing comes (steps S11 and S12), the control device 11 counts up a counter (step S13). When the count value is 1, it is determined that it is the defrost start timing at the end of the normal cooling control operation, and it is determined whether or not the defrost start timing is extended based on the estimated outside air temperature (steps S14 and S15). . When the count value is 2 or more, it is determined that the defrost start timing is at the end of the extension operation, and it is determined whether the defrost start timing is extended only by the door open flag and the forced operation flag. (Steps S14 and S16). In this case, step S1
As the constant value to be compared with the integrated timer value at 1, different values are set when the counter is 0 (normal cooling control) and when the counter is 1 or more (extended operation). That is, when the counter is 0, the constant value is 10 hours, and when the counter is 1 or more, it is 100 minutes.

According to such a configuration, the operation of the integrating timer of the compressor 23 and the defrosting condition of the defrosting condition necessary for determining whether to postpone the defrosting start timing at the defrosting start timing at the end of the execution of the extension operation. Since the determination can be shared with the normal cooling control, the same effects as those of the first embodiment can be obtained, the configuration of the control device 11 can be simplified, the development period can be shortened, and the cost can be reduced. be able to.

FIG. 7 shows a flowchart of the control device according to the third embodiment of the present invention. The difference of the third embodiment from the first embodiment is that, when the forced operation is performed during the execution of the extension operation, the time counting of the extension operation is interrupted during the forced operation (step). S17, S
18, S19, S20).

According to such a configuration, when the forced operation is executed during the execution of the extension operation, the end timing of the extension operation and the end timing of the forced operation can be always shifted as shown in FIG. It is possible to prevent a problem that the defrosting operation is immediately executed at the end timing of the forced operation.

The present invention is not limited to the above embodiment, but can be modified or expanded as follows.

The defrost control means may be constituted by a device for executing a normal cooling operation, a device for executing the first extension operation, and a device for executing the second extension operation.

[0053] The door opening storage means may be configured such that when the door is opened, the temperature inside the refrigerator changes, so that it is estimated based on the change.

The outside air temperature judging means may be configured to estimate the outside air temperature based on the operation rate of the compressor 23 since the operation rate of the compressor 23 changes according to the outside air temperature.

[0055]

As apparent from the above description, the following effects can be obtained by the refrigerator defroster of the present invention.

According to the first aspect of the present invention, the defrosting control means, when the condition that does not require the defrosting operation is satisfied at the preset defrosting start timing,
The first to postpone the defrost start timing by a certain time
When a condition that does not require the defrosting operation is satisfied at the defrosting start timing at the end of the first extending operation, the second operation of further delaying the defrosting start timing by a certain time is performed. Defrosting operation for extended operation
Since it is repeatedly executed until it becomes necessary, it is possible to defrost the cooler at an appropriate timing while saving labor with a simple configuration.

According to the second aspect of the present invention, when a condition that does not require defrosting is satisfied at the defrosting start timing at the end of the extension operation, the defrosting start timing is set to the integrated operating time of the compressor. Since the advance is performed until the predetermined time is reached, the defrost start timing can be accurately set.

According to the third aspect, since the outside air temperature determining means estimates the outside air temperature based on the operating rate of the compressor, a special temperature sensor for detecting the outside air temperature can be omitted. .

According to the fourth aspect of the invention, the outside air temperature judging means is based on the temperature detected by the temperature sensor for detecting the temperature of the predetermined storage space in which the defrost control device as the defrost control means is stored. Since the outside air temperature is estimated, it is not necessary to lead the lead wire of the temperature sensor for detecting the outside air temperature from the closed space.

According to the fifth aspect, when the forced operation is performed during the execution of the extension operation, the defrost control means suspends the time measurement of the extension operation until the forced operation is completed. The disadvantage that the cooler rapidly cooled by the forced operation is heated by the defrosting operation can be avoided.

[Brief description of the drawings]

FIG. 1 is a flowchart of a control device showing a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing an electric configuration of the refrigerator.

FIG. 3 is a timing chart when the extension operation is not performed.

FIG. 4 is a diagram corresponding to FIG. 3 when an extension operation is performed twice.

FIG. 5 is a diagram corresponding to FIG. 3 when an extension operation is performed a specified number of times.

FIG. 6 is a view corresponding to FIG. 1, showing a second embodiment of the present invention.

FIG. 7 is a view corresponding to FIG. 1 showing a third embodiment of the present invention.

FIG. 8 is a timing chart when the extension operation is performed once.

FIG. 9 is a diagram corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

2 is a freezing room, 3 is a refrigerator room, 4 is a vegetable room, 5-7 are doors, 8
10 to 10 are door switches, 11 is a control device (defrost control means,
Door open storage means, forced operation storage means, outside air temperature determination means), 12 is a forced operation button, 15 is a cooler, 21 is a refrigeration temperature sensor, and 23 is a compressor.

Claims (5)

(57) [Claims] 1. A defrost control means for performing a defrost operation of a cooler at a preset defrost start timing, and a door opening for storing that the refrigerator door has been opened at least after a previous defrost operation. Storage means, forced operation storage means for storing that forced continuous operation of the compressor for the cooler has been performed at least since the previous defrosting operation, and outside air temperature determination means for detecting or estimating the ambient temperature of the refrigerator The defrost control means, when the defrost start timing comes, the door open storage means and the forced operation storage means are in a non-stored state and the detected temperature or estimated temperature by the outside air temperature determination means is When the temperature is within the predetermined temperature range, a first extension operation for delaying the defrost start timing by a predetermined time is executed, and a defrost start timing at the end of the first extension operation is performed. Actual defrosting operation when the door opening storing means and the forced operation storage means is a storage state at timing
If it is in the non-storage state, the second extension operation of delaying the defrost start timing by a certain time is repeated.
And execute the second extension operation the specified number of times.
The defrosting start time when the
The door open storage means and the forced operation
A defrosting device for a refrigerator, wherein a defrosting operation is performed when the storage means is in a storage state . 2. A defrosting control means for executing a defrosting operation of a cooler at a preset defrosting start timing, and a door opening for storing that the refrigerator door has been opened at least after a previous defrosting operation. Storage means, forced operation storage means for storing that forced continuous operation of the compressor for the cooler has been performed at least since the previous defrosting operation, and outside air temperature determination means for detecting or estimating the ambient temperature of the refrigerator The defrost control means, when the defrost start timing comes, the door open storage means and the forced operation storage means are in a non-stored state and the detected temperature or estimated temperature by the outside air temperature determination means is When the temperature is within the predetermined temperature range, the first defrosting start timing is postponed until the accumulated operation time of the compressor reaches a predetermined time, and the defrosting start timing is executed. When the defrosting start timing at the time of the first extension operation end the door opening storing means and the forced operation storage means is a storage state executes the defrosting operation, when was non-memory condition, the The defrosting start timing is further repeated by executing a second extension operation in which the accumulated operation time of the compressor is advanced until the accumulated operation time reaches a certain time, and
When the second extension operation is performed a specified number of times or when the second
The door is opened at the defrost start timing at the end of the extension operation.
The release storage means and the forced operation storage means are in the storage state.
A defrosting device for performing a defrosting operation when the defrosting operation is performed. 3. The defrosting device for a refrigerator according to claim 1, wherein the outside air temperature determining means is configured to estimate the outside air temperature based on an operation rate of the compressor. 4. The defrosting control means includes a defrosting control device that performs an extension operation for delaying the defrosting start timing, and controls a temperature of a predetermined storage space in which the defrosting control device is stored. The defrosting device for a refrigerator according to claim 1 or 2, further comprising a temperature sensor for detecting, wherein the outside air temperature determination unit is configured to estimate the outside air temperature based on the temperature detected by the temperature sensor. . 5. The defrost control means is configured to, when a forced operation is performed during the execution of the extension operation, suspend the time measurement of the extension operation until the forced operation ends. The defrosting device for a refrigerator according to claim 1 or 2, wherein: