JP4876675B2 - Refrigerated showcase - Google Patents

Description

The present invention relates to operation control of a compressor in a refrigerated showcase.

Refrigerated showcases installed in supermarkets and other stores are equipped with refrigeration equipment such as compressors and coolers as is well known, and the showcase controller attached to the showcase supports the internal temperature according to the type of product. The compressor is turned on and off by the showcase controller so that the set target temperature is maintained (see, for example, Patent Document 1).
Japanese Utility Model Publication No. 55-3274

There are various types of products stored in showcases. For example, products that need to be cooled at low temperatures such as frozen foods freeze at temperatures below 0 ° C, such as tofu and beverages. Some products do not want to be. However, in order to be able to handle these various products with a single model, the showcase has a large range of internal temperatures that can be set to any temperature, and has a large compressor capacity. It has become.

On the other hand, the internal temperature is automatically controlled to the target temperature set by the showcase controller. However, when the target temperature is high, a compressor with a large cooling capacity is used. It will cool to below the target temperature over time. Therefore, as shown in the graph of FIG. 12, the operation of the compressor is stopped immediately after the start of cooling, or the operation is performed with the output reduced.

Lubricating oil circulates in the compressor, and in order for this oil to circulate and return to the compressor, the compressor needs to be operated at a predetermined output or more for a predetermined time (usually 3 minutes). However, when the compressor is operated only for a short time as described above, or when it is operated for a long time with the output reduced, the operation time and output required for the lubricating oil to return to the compressor can be secured. Therefore, the oil does not return to the compressor, resulting in compressor damage.

In order to avoid such a situation, conventionally, for example, a function has been given such as setting a minimum time for the start-up time of the compressor or putting a high output operation in the middle when a low output operation is continued. Doing so may cause an excessively cold state, and is not considered effective as a countermeasure.

The object of the present invention is to eliminate the inconvenience of the conventional example, and when temperature control is performed using a compressor having a large capacity, the time required for the lubricating oil to return to the compressor is high even if the target temperature is high. To provide a method for controlling the operation of a compressor for a refrigerated showcase that can automatically set an operation time that can be secured, prevent damage to the compressor, and also prevent over-cooling of products that should not be frozen. .

In order to achieve the above-mentioned object, the present invention includes a refrigeration apparatus such as a compressor and a cooler, and the compressor is turned on and off by a showcase controller so that the inside of the cabinet has a predetermined target temperature. In a refrigerated refrigerator-free showcase that controls the temperature so that the temperature is maintained, the operation time from the start of the compressor to the stop in temperature control operation is measured, and from the next start of the compressor based on the value of this operation time The operation time until the stop is set to a time required for the compressor lubricating oil to return to the compressor .

The present invention measures the operation time from the start of the compressor to the stop in the temperature control operation, and if this operation time is less than the time required for the lubricating oil to return to the compressor, the next time As the time required for the oil to return to the compressor, for example, forcibly operating for 3 minutes, damage to the compressor can be prevented.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a flowchart of a control operation showing a first embodiment of the freezer / refrigeration showcase of the present invention, and FIG. 2 is a flowchart of a temperature control operation in which this control operation is performed.

If it demonstrates from the temperature control operation | movement used as the base of the operation control of a compressor, the target temperature of the chamber internal temperature of the said showcase will be preset according to the kind of goods with the controller for showcases. Then, the compressor is turned on and off, and the cool air cooled by the cooler is sent into the warehouse, and the product in the warehouse is held at the target temperature.

This target temperature is maintained by turning on the compressor (step 1), performing a cooling operation, and if the detected internal temperature becomes lower than the target temperature (step 2), depending on the output from the controller for the showcase The compressor is turned off (step 3) and the cooling operation is stopped.

If the internal temperature rises due to the stop of the compressor, and the detected internal temperature becomes higher than the target temperature + differential temperature (step 4), the compressor is turned on again to cool the internal temperature. . This is repeated to keep the internal temperature at the target temperature.

Although the internal temperature is controlled as described above, when the target temperature is set high, the compressor is turned on in a short time after the compressor is turned on, and the compressor may be damaged. Therefore, in order to avoid such a situation, the present invention measures the on-time of the compressor as the first embodiment as shown in the flowchart of FIG. 1, and when the compressor is turned off by the temperature control (step) 5) It is judged whether the operation time of the compressor was a short time within 30 seconds (step 6), and further, whether the operation within 30 seconds was continued twice (step 7). The on-operation time of the machine is set to be at least 180 seconds (step 8).

As a result, when the oil for lubrication cannot return to the compressor in a short time of 30 seconds or less for two consecutive on-operation times of the compressor, the next on-operation time is forcibly set to 180 seconds (3 minutes). So the oil can be returned to the compressor in this time. The setting of 3 minutes is the time that the lubricating oil can normally return to the compressor.

Also, if the previous compressor on-operation time is between 30 seconds and 120 seconds (step 9), it is determined that there is a high possibility that the oil has hardly returned to the compressor, and the next on-operation time is set. Forcibly set to 180 seconds (3 minutes) (step 8).

Further, when the previous on-operation time of the compressor is between 120 seconds and 180 seconds (step 10), it is determined that a considerable amount of oil has returned to the compressor, and such operation is continued twice. Then, the next on-operation time is forcibly set to 180 seconds (step 11). If it is not continuous twice, a normal temperature control operation is performed according to the flowchart shown in FIG. 2 (step 12).

Further, if the previous compressor on-operation time is 180 seconds or more, it is determined that the oil has completely returned to the compressor (step 10), and a normal temperature control operation is performed (step 12).

Thus, the length of the next on-operation time is determined by the length of the previous on-operation time of the compressor and the number of times, and the time for the oil to return to the compressor is secured. It should be noted that the length and number of times of the previous on-operation time and the specific numerical values of the length of the next on-operation time, which are standards for determining the next on-operation time, are not limited to the above-described embodiment.

3 and 4 show a second embodiment. When the previous compressor on-operation time is short, the next compressor start timing is the normal operation as control for returning the lubricating oil to the compressor. It was later than the time of, so that the next on-operation time will be longer.

This operation will be described with reference to a flowchart. In the compressor temperature control operation, as shown in FIG. 4, the compressor is turned on and the cooling operation is performed (step 13), and the internal temperature reaches the set target temperature (step 14). Then, the compressor is turned off (step 15).

As a result, if the internal temperature rises and the current internal temperature becomes higher than the target temperature + differential temperature (step 16), and further, a set delay time until the compressor is turned on has elapsed (step 17), At this time, the compressor is restarted (step 13). This is repeated to keep the internal temperature at the target temperature.

By the way, after the compressor is turned off (step 18), when the previous operation time of the compressor is less than 3 minutes (step 19), it is determined that the oil has not returned to the compressor, When the compressor is restarted after the set delay time in (Step 17), the next start delay time of the compressor is set by extending 30 seconds (Step 20), and the set delay time including this 30-second extension has elapsed. Restart the compressor later.

As a result, the compressor restarts after a delay time longer than the initial delay time has elapsed, so that the internal temperature further rises before restarting, and as a result, the compressor is turned on the next time. The operation requires more time than the previous time to reach the target temperature, and it is predicted that the on-operation time will be longer than the previous time, whereby the oil can be returned to the compressor.

If the on-operation time of the compressor becomes longer and becomes more than 3 minutes 30 seconds in this way (step 21), the delay time for starting the compressor from the next time is reduced by 30 seconds (step 21). 23) The compressor was restarted before the internal temperature rose significantly to prevent the on-operation time from becoming longer than necessary.

Note that the compressor's on-operation time is not less than 3 minutes (step 19), not more than 3 minutes 30 seconds (step 21), and if the time is appropriate, it is determined that the oil has returned to the compressor. Then, the temperature control operation is performed with the compressor delay operation time set initially (step 22).

FIG. 5 shows a third embodiment. In the second embodiment, when the previous on-operation time of the compressor is short, as control for returning the lubricating oil to the compressor in order to prevent compressor damage, Although the set value of the compressor delay operation time is changed, the third embodiment changes the value of the differential temperature that is a condition for restarting the compressor instead of the delay time.

This control operation will be described with reference to the flowchart of FIG. 5. In the compressor temperature control operation, as shown in FIG. 4, the compressor is turned on and the cooling operation is performed (step 13), and the internal temperature reaches the set target temperature. (Step 14), the compressor is turned off (Step 15).

As a result, if the internal temperature rises and the current internal temperature becomes higher than the target temperature + differential temperature (step 16), and further, a set delay time until the compressor is turned on has elapsed (step 17), At this time, the compressor is restarted (step 13). This is repeated to keep the internal temperature at the target temperature.

By the way, after the compressor is turned off (step 24), if the previous operation time of the compressor is less than 3 minutes (step 25), it is determined that the oil has not returned to the compressor, The differential temperature set as the compressor start start temperature from the next time in (Step 16) is set, for example, 0.5 ° C. higher than the currently set value (Step 26).

Then, when the internal temperature becomes higher than the newly set differential temperature, which is higher than the previous time, the compressor is restarted. Therefore, the internal temperature rises more than before before restarting. As a result, the next compressor on-operation requires more time than the previous to reach the target temperature, and the on-operation time is longer than the previous time. This is expected to allow oil to be returned to the compressor.

If the on-operation time of the compressor becomes longer and becomes more than 3 minutes 30 seconds in this way (step 27), the differential temperature, which is the condition for starting the compressor from the next time, is set to 0. The temperature was lowered by 5 ° C. (step 28), and the compressor was restarted before the inside temperature rose greatly so that the on-operation time was not longer than necessary.

Note that the compressor's on-operation time is not less than 3 minutes (step 25) and is not more than 3 minutes 30 seconds (step 27), and if the time is appropriate, it is determined that the oil has returned to the compressor. Then, the temperature control operation is performed at the initially set differential temperature (step 29).

FIGS. 6 to 9 show the fourth embodiment, in which the compressor driving device is an inverter system and the temperature control is performed by changing the value of the compressor output. As shown in the flowchart of FIG. 7, the temperature control is a basic control method. The compressor is turned on at the standard rotation speed (step 30), and then waits for one minute (step 31). If the temperature has not yet reached the set target temperature (step 32) but is decreasing and the difference from the target temperature is within 5 ° C (step 36), the compressor output is increased by 5%. (Step 37), Control is performed so that the internal temperature quickly reaches the target temperature.

On the other hand, if the internal temperature measured in (Step 32) has reached the target temperature but is not 2 ° C. or more lower than the target temperature (Step 33), the compressor output is reduced by 2% (Step 35). ) Reduce the output a little.

On the other hand, if the temperature is lower than the target temperature by 2 ° C. or more in (Step 33), the compressor output is reduced by 5% (Step 34), and the internal temperature is lower than the target temperature by operating with a small output. Is controlled so that it does not drop significantly.

In a compressor that performs such temperature control, oil cannot be recovered in the compressor if the output of the compressor is greatly reduced. As a basic control, the output of the current compressor is shown in the flowchart of FIG. Is 30% or less of the rating (step 38), and if the compressor on-time has continued for 10 minutes in this state (step 39), it is determined that the oil has not sufficiently returned to the compressor. The output operation is forcibly performed for 3 minutes so that the oil returns to the compressor (step 40).

Also, even if the current compressor output is 30% or more of the rated value (step 38), if it is 50% or less (step 41), the on-operation time of the compressor continues for 20 minutes in this state However, it is determined that the oil has not sufficiently returned to the compressor, and the rated output operation is forcibly performed for 3 minutes so that the oil returns to the compressor (step 40).

The fourth embodiment is based on the basic control according to the flowchart shown in FIG. 6. In the control operation according to the flowchart of FIG. 6, the compressor output is small for a predetermined time (for example, 10 minutes or 20 minutes). If the ON operation time continues, the rated output operation for 3 minutes is immediately forcibly performed. However, in the control operation according to the flowchart of FIG. 8, the rated output operation for 3 minutes is forcibly started immediately. Instead, the compressor is stopped for a predetermined time or the output of the compressor is forcibly reduced. Since the operation of the temperature control operation in FIG. 9 is the same as that in FIG. 7, the description thereof is omitted here.

That is, when the temperature control operation is performed according to the flowchart of FIG. 9 (step 43), the current compressor output is 30% or less of the rating (step 44), and the ON operation time continues for 10 minutes or more. (Step 45), the compressor is forcibly stopped for a forcible stop time preset in the showcase controller (step 46). This forced stop time is set to 3 minutes as an initial value, for example.

Since the internal temperature rises due to this forced stop, if the temperature control operation is performed according to the operation of the flowchart shown in FIG. 9 after the forced stop time has elapsed (step 47), the rising internal temperature is set. The compressor output is increased to lower the target temperature.

As a result, if the output of the compressor is 70% or more of the rated value and the on operation is performed for 3 minutes or more and 4 minutes or less (step 48) (step 50), the proper operation state in which oil can be returned to the compressor. The temperature control operation is carried out as it is (step 43).

On the other hand, when the ON operation with the compressor output of 70% or more continues for 4 minutes or more (step 50), it takes a lot of time to lower the internal temperature to the target temperature. It is determined that the internal temperature when the temperature control operation starts in (Step 47) is too high, that is, the stop time is too long, and the next forced stop time is subtracted by 30 seconds (Step 51). The process proceeds to a temperature control operation (step 43).

Also, in the temperature control operation after the forced stop of the compressor (step 47), if the compressor output is not less than 70% of the rated value and does not operate for more than 3 minutes (step 48), during the forced stop time It is determined that the internal temperature has not risen sufficiently, and the next forced stop time is added for 30 seconds so that the internal temperature further increases during the forced stop time (step 49). Transition to operation (step 43).

Also, if the current compressor output is 50% or less of the rated value (step 52) and the ON operation time continues for 20 minutes or more (step 53), it is forcibly preset in the showcase controller. According to the forced output reduction operation time, the compressor output is forcibly reduced to, for example, 20%, and the on operation is performed for 3 minutes (step 54). For example, 3 minutes is set as the initial value of the forced output reduction operation time.

Since the internal temperature rises due to this forced output reduction operation, if the temperature control operation is performed according to the operation of the flowchart shown in FIG. 9 after the forced output reduction operation time has elapsed (step 55), the internal temperature that is rising The output of the compressor is increased to lower the temperature to the set target temperature.

As a result, if the output of the compressor is 70% or more of the rated value and the on operation is performed for 3 minutes or more and 4 minutes or less (step 56) (step 58), it is determined that the operation state is appropriate. Then, the temperature control operation is performed as it is (step 43).

On the other hand, when the ON operation with the compressor output of 70% or more continues for 4 minutes or more (step 58), it takes a lot of time to lower the internal temperature to the target temperature. It is determined that the internal temperature when the temperature control operation starts in (Step 55) has risen too much, that is, the forced output reduction operation time is too long, and the next forced output reduction operation time is subtracted by 30 seconds. (Step 59), the process proceeds to the temperature control operation (step 43).

Further, in the temperature control operation after the forced output reduction operation of the compressor (step 55), when the compressor output is not less than 70% of the rated value and does not operate for more than 3 minutes (step 56), the forced output reduction operation is performed. It is determined that the internal temperature has not risen sufficiently during the time, and the next forced output reduction operation time is added for 30 seconds so that the internal temperature further increases during the forced stop time ( Step 57) Shift to temperature control operation (Step 43).

10 and 11 show a fifth embodiment. In the fourth embodiment, when it is determined that the oil has not sufficiently returned to the compressor, the compressor is forcibly stopped for a certain period of time or is output for a certain period of time. In the fifth embodiment, in addition to this, after the compressor is forcibly stopped for a certain period of time or after the output is reduced for a certain period of time, the internal temperature is detected. A normal temperature control operation was started when the internal temperature was higher than a predetermined value.

This operation will be described with reference to the flowchart of FIG. Since the normal temperature control operation shown in FIG. 11 is the same as that shown in FIG. 9, detailed description thereof is omitted.

When the temperature control operation is carried out in accordance with the temperature control operation shown in FIG. 10 (step 60), the current compressor output is 30% or less of the rating (step 61), and the ON operation time continues for 10 minutes or more. If so (step 62), the compressor is forcibly stopped for a forcible stop time preset in the showcase controller (step 63). This forced stop time is set to 3 minutes as an initial value, for example.

Because the internal temperature rises due to this forced stop, the internal temperature is detected after the forced stop time has elapsed, and the internal temperature rises to a temperature value required to allow restart after the forced compressor stop time has elapsed. If the temperature rise value has reached the set value (step 64), the temperature control operation is performed according to the operation of the flowchart shown in FIG. 10 (step 65).

In this case, for example, 4 ° C. is set as the initial temperature rise value. In the restarted temperature control operation, the output of the compressor is increased in order to lower the rising internal temperature to the set target temperature.

As a result, if the output of the compressor is 70% or more of the rated value and the on operation is performed for 3 minutes or more and 4 minutes or less (step 66) (step 68), an appropriate operation state in which oil can be returned to the compressor. The temperature control operation is carried out as it is (step 60).

On the other hand, if the ON operation with the compressor output of 70% or more continues for 4 minutes or more (step 68), the internal temperature before restarting the compressor in (step 65) increases too much. The temperature rise value for permitting restart after the next compressor forced stop time is set lower by 2 ° C. (step 69) and the process proceeds to the temperature control operation (step 60).

Further, in the temperature control operation after the forced stop of the compressor (step 65), when the compressor output is 70% or more of the rated value and does not operate for 3 minutes or more (step 66), during the forced stop time. Judging that the internal temperature has not risen sufficiently, the temperature rise value after the next forced stop time is set 2 ° C higher, and the internal temperature after the forced stop time has increased further (Step 67) The process proceeds to the temperature control operation (Step 60).

Further, when the current compressor output is 50% or less of the rated value (step 70) and the on-operation time continues for 20 minutes or more (step 71), it is forcibly preset in the showcase controller. In accordance with the forced output reduction operation time, the compressor output is forcibly reduced to, for example, 20%, for example, for 3 minutes (step 72).

Since the internal temperature rises due to this forced output reduction operation, the internal temperature is detected after the forced output reduction operation time elapses, and the internal temperature permits normal temperature control operation after the compressor forced output reduction operation time elapses. Therefore, it is determined whether the temperature has increased to a necessary temperature value. If the temperature increase value has reached the set value (step 73), the temperature control operation is performed according to the operation of the flowchart shown in FIG. 74).

In this case, for example, 4 ° C. is set as the initial value of the temperature rise value. Then, in the restarted temperature control operation, the output of the compressor is increased in order to lower the internal temperature rising according to the operation of the flowchart shown in FIG. 10 to the set target temperature.

As a result, if the output of the compressor is 70% or more of the rated value and the on operation is performed for 3 minutes or more and 4 minutes or less (step 75) (step 77), the proper operation state in which oil can be returned to the compressor. The temperature control operation is carried out as it is (step 60).

On the other hand, when the ON operation with the compressor output of 70% or more continues for 4 minutes or more (step 77), it takes a lot of time to lower the internal temperature to the target temperature. It is determined that the internal temperature when the temperature control operation starts in (Step 74) has risen too much, that is, the set value of the temperature rise value as the restart condition after the forced output reduction operation time has passed is too high. Then, the temperature rise value after the elapse of the next forced output reduction operation time is set 2 ° C. lower (step 78), and the process proceeds to the temperature control operation (step 60).

Further, in the temperature control operation after the forced output reduction operation of the compressor (step 74), when the compressor output is 70% or more of the rated value and does not operate for 3 minutes or more (step 75), the forced output reduction operation is performed. It is determined that the set value of the temperature rise value as the restart condition after the lapse of time is too low, and the temperature rise value after the next lapse of the forced output reduction operation time is set 2 ° C higher (step 76). The process proceeds to a temperature control operation (step 60).

As described above, in the temperature control operation of the compressor, an on-operation time that allows the lubricating oil to be returned to the compressor is secured to prevent damage to the compressor, and at the same time, the cooling operation is performed more than necessary. It is possible to operate at a temperature suitable for the goods in the warehouse, preventing it from becoming long.

It is a flowchart which shows the processing operation of the compressor damage prevention driving | operation judgment which shows 1st Embodiment of the freezer / refrigeration showcase of this invention. It is a flowchart which shows the operation | movement of the temperature control operation in which 1st Embodiment of the freezer refrigerator showcase of this invention is implemented. It is a flowchart which shows the processing operation of the compressor damage prevention driving | operation judgment which shows 2nd Embodiment of the freezer / refrigeration showcase of this invention. It is a flowchart which shows the operation | movement of the temperature control driving | operation by which 2nd Embodiment of the freezer / refrigeration showcase of this invention is implemented. It is a flowchart which shows the processing operation of the compressor damage prevention driving | operation judgment which shows 3rd Embodiment of the freezer / refrigeration showcase of this invention. It is a flowchart which shows the processing operation of the compressor damage prevention driving | operation judgment used as the premise of 4th Embodiment of the freezer / refrigeration showcase of this invention. It is a flowchart which shows the operation | movement of the temperature control operation | movement used as the premise of 4th Embodiment of the freezer / refrigeration showcase of this invention. It is a flowchart which shows the processing operation of the compressor damage prevention driving | operation judgment which shows 4th Embodiment of the freezer / refrigeration showcase of this invention. It is a flowchart which shows the operation | movement of the temperature control operation in which 4th Embodiment of the freezer refrigerator showcase of this invention is implemented. It is a flowchart which shows the processing operation of the compressor damage prevention driving | operation determination which shows 5th Embodiment of the freezer / refrigeration showcase of this invention. It is a flowchart which shows the operation | movement of the temperature control operation in which 5th Embodiment of the freezer refrigerator showcase of this invention is implemented. It is a graph which shows the relationship between the internal temperature by compressor operation, and elapsed time.

Claims (12)

Compressed in a temperature controlled operation in a refrigerated showcase equipped with a refrigeration system such as a compressor or cooler, and temperature controlled so that the compressor is turned on and off by the showcase controller to maintain the interior at a predetermined target temperature. Measure the operation time from the start of the machine to the stop, and based on this value of the operation time, the operation time from the next start of the compressor to the stop will be calculated so that the compressor lubricant returns to the compressor. A refrigerated showcase set to the required time. Compressed in a temperature controlled operation in a refrigerated showcase equipped with a refrigeration system such as a compressor or cooler, and temperature controlled so that the compressor is turned on and off by the showcase controller to maintain the interior at a predetermined target temperature. The operation time from the start of the machine to the stop is measured and the number of operations repeated in this operation time is detected. Based on the value and the number of this operation time, the compressor is started and stopped from the next time. A refrigerated showcase characterized in that the operating time is set to the time required for the compressor lubricant to return to the compressor. Compressed in a temperature controlled operation in a refrigerated showcase equipped with a refrigeration system such as a compressor or cooler, and temperature controlled so that the compressor is turned on and off by the showcase controller to maintain the interior at a predetermined target temperature Measure the operation time from when the machine is started until it stops, and based on the value of this operation time, the stop time until the next start of the compressor is used to return the compressor lubricant to the compressor. A freezing and refrigeration showcase that is set to a time during which operation time is secured. The freezing and refrigeration showcase according to claim 3, wherein the stop time is determined by further adding a certain time at the start timing of the compressor by a normal temperature control operation. The stop time is automatically adjusted and set so that the time from the start of the compressor to the stop by the normal temperature control operation becomes the operation time required for the compressor lubricating oil to return to the compressor. The frozen and refrigerated showcase according to claim 3. Compressed in a temperature controlled operation in a refrigerated showcase equipped with a refrigeration system such as a compressor or cooler, and temperature controlled so that the compressor is turned on and off by the showcase controller to maintain the interior at a predetermined target temperature Measure the operating time from when the machine is started until it stops, and based on this operating time value, set the starting start temperature after the next compressor stop higher than the starting temperature by normal temperature control operation Refrigerated showcase featuring The activation start temperature setting of the time to stop the activation of the compressor of the normal temperature control operation the compressor lubricating oil is automatically adjusted and set so that the operating time required to return to the compressor The freezer-refrigerated showcase according to claim 6. In a freezer / refrigeration showcase having a refrigeration apparatus such as a compressor and a cooler, and controlling the output of the compressor by a showcase controller to control the temperature so as to maintain the interior at a predetermined target temperature. In the case of the inverter system, a freezing and refrigeration showcase in which the rated output operation necessary for the compressor lubricating oil to return to the compressor is carried out next time based on the previous compressor output and operating time value.
In a freezer / refrigeration showcase having a refrigeration apparatus such as a compressor and a cooler, and controlling the output of the compressor by a showcase controller to control the temperature so as to maintain the interior at a predetermined target temperature. In the case of the inverter method, the output after the next compressor start-up is increased by lowering or stopping the compressor output for a certain period of time based on the previous compressor output and the operating time value. A refrigerated showcase characterized by carrying out the rated operation necessary to return to The time until the next start after the compressor is stopped is automatically adjusted and set so as to ensure the operation time required for the lubricant of the compressor to return to the compressor. 9. The refrigerator-freezer showcase of 9. 10. The rated operation is characterized in that the set value of the temperature rise value is set higher than that during normal temperature control operation, starts after reaching the target temperature, and then returns to the initially set target temperature. Refrigerated showcase. 10. The refrigeration according to claim 9, wherein the temperature rise value at the start of the rated operation is automatically adjusted and set so as to secure an operation time required for the lubricating oil of the compressor to return to the compressor. Refrigerated showcase.

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