JP5579556B2 - Cooling system - Google Patents

Description

  The present invention relates to a cooling device including a control device that controls the rotational speed of a compressor constituting a refrigeration cycle.

  2. Description of the Related Art Conventionally, for example, a cooling device employed in a showcase has a predetermined refrigerant circuit in which a compressor, a radiator, a decompression device, an evaporator, and the like are sequentially connected in a circular pattern by piping, and the refrigerant circuit includes A predetermined amount of refrigerant is sealed. When the compressor is operated, the refrigerant is compressed into a high-temperature and high-pressure gas state and flows into the radiator. In the radiator, the refrigerant dissipates heat and is condensed and liquefied, and then decompressed by a decompression device and supplied to the evaporator. In the evaporator, the liquid refrigerant after being depressurized evaporates, and at that time, the cooling effect is exhibited by absorbing heat from the surroundings (see, for example, Patent Document 1).

JP 2004-232994 A

  Incidentally, the rotational speed of the compressor is normally controlled between the minimum rotational speed and the maximum rotational speed by the control device. That is, when the temperature (current temperature) of the display room, which is the space to be cooled in the showcase, reaches the upper limit temperature of the cooling temperature range, the control device starts the compressor, and the current temperature reaches the lower limit temperature of the cooling temperature range. Stop the compressor if it drops. In addition, the control device, based on the output of various sensors for detecting the temperature of the refrigerant and the temperature in the cabinet, sets the minimum rotation speed and the maximum so that the current temperature in the display room is within a predetermined cooling temperature range with respect to the target temperature. The rotational speed of the compressor is controlled within the rotational speed range.

In the conventional compressor rotation speed control, the operation rotation speed (frequency) of the compressor motor is PID controlled by an inverter device, and the current temperature is controlled more smoothly and accurately to the target temperature. The PID control is executed by a PID arithmetic processing unit provided inside the control device. Specifically, a proportional operation for calculating a proportional amount by multiplying a deviation e between the current temperature and the target temperature by a proportional control coefficient, and an integral value of the deviation e (the deviation e from the cooling target temperature is integrated in the time axis direction). Value) is multiplied by the integral control coefficient to calculate the integral amount, and the differential value is calculated by multiplying the differential value of the deviation e (inclination of the internal temperature change) by the differential control coefficient and calculating the derivative amount. The operating speed of the compressor motor is determined from the operation amount obtained by adding the control amount. An arithmetic expression is shown below.
Arithmetic formula Operation amount = Current operation speed + Proportional amount + Integration amount + Derivative amount Proportional amount = (Current temperature-Target temperature) x Kp
Integral amount = (sum of deviations for a predetermined time (current temperature−target temperature)) × Ki
Differential amount = (Current temperature−Previous chamber temperature) × Kd

  Normally, if the current temperature falls below the target temperature, the compressor speed decreases, but even if the minimum speed is reached, the current temperature gradually decreases until the target temperature falls below the lower limit temperature and the compressor is stopped. It will take a relatively long time. Therefore, the operation in a state where the temperature is too cool from the target temperature is performed for a long time, which causes an increase in the accumulated power consumption.

  Therefore, by controlling the rotation speed of the compressor by switching the deviation e to the deviation between the current temperature decrease rate and the target temperature decrease rate, the rotation speed control based on the cooling rate in the refrigerator is realized, thereby the current temperature. Is controlled to stop the compressor by lowering the temperature to a predetermined lower limit temperature at an early stage.

  However, particularly in the case of a cooling storehouse whose opening is closed by a door and the cooling target temperature is in the refrigeration temperature range, the control uses a temperature sufficiently higher than the cooling capacity as the target temperature in the chamber. Even in the vicinity of the thermo-off temperature, the cooling speed does not decrease, it becomes difficult to perform control with the temperature decrease rate as a deviation, and it is difficult to cool the evaporator immediately before stopping the compressor.

  The present invention has been made in order to solve the conventional technical problem, and immediately before stopping the compressor, the evaporator is cooled, and the operating rate of the compressor is lowered, thereby reducing the accumulated power consumption. Provided is a cooling device capable of achieving reduction.

  In order to solve the above-described problem, the cooling device of the present invention includes a control device that controls the rotational speed of the compressor constituting the refrigeration cycle, and the control device is a deviation between the current temperature and the target temperature. When the compressor speed is controlled within a range between a predetermined maximum speed and a minimum speed so that the deviation e becomes zero based on e, and the current temperature falls to a predetermined lower limit temperature lower than the target temperature The compressor is stopped, and when the current temperature is lowered to a predetermined pre-stop temperature close to the lower limit temperature, the rotation speed of the compressor is increased by a predetermined value.

  The invention of claim 2 is characterized in that, in the above invention, the pre-stop temperature is lower than the target temperature and higher than the lower limit temperature by a predetermined value.

  The invention according to claim 3 is characterized in that, in each of the above-mentioned inventions, the control device executes the rotation speed increase control of the compressor by the pre-stop temperature when the outside air temperature is higher than a predetermined value.

  The invention of claim 4 is characterized in that, in each of the above inventions, the control device increases the minimum number of revolutions by a predetermined value when the current temperature falls to the pre-stop temperature.

  According to a fifth aspect of the present invention, in each of the above-described inventions, a heat insulating box having a storage chamber formed therein, an evaporator forming a refrigeration cycle, and a blower for circulating cold air exchanged with the evaporator into the storage chamber; The storage room has a door that can be opened and closed freely, the current temperature is the current temperature of the storage room, and the control device operates the fan even when the compressor is stopped. To do.

  According to a sixth aspect of the present invention, in each of the above-mentioned inventions, the control device, based on the deviation e, performs proportional (P) control, integral (I) control, differential (D) control, proportional integral (PI) of the rotational speed of the compressor. Control, proportional derivative (PD) control, integral derivative (ID), or proportional integral derivative (PID) control is performed.

  According to the present invention, in the cooling device including the control device that controls the rotation speed of the compressor constituting the refrigeration cycle, the control device sets the deviation e to zero based on the deviation e between the current temperature and the target temperature. The compressor speed is controlled within the range of the predetermined maximum speed and the minimum speed so that when the current temperature falls to a predetermined lower limit temperature lower than the target temperature, the compressor is stopped and the current temperature Is reduced to a predetermined pre-stop temperature close to the lower limit temperature, by increasing the rotation speed of the compressor by a predetermined value, immediately before the current temperature is reduced to the lower limit temperature and the compressor is stopped, The evaporator can be cooled.

  As a result, the thermo-off time from when the compressor is stopped to when the current temperature reaches the upper limit temperature and the compressor is restarted can be extended, and the entire thermocycle time can be extended. Therefore, the operation rate of the compressor can be lowered.

  According to the invention of claim 2, in the above invention, since the pre-stop temperature is lower than the target temperature and higher than the lower limit temperature by a predetermined value, it is possible to realize cooling that increases the rotational speed immediately before the compressor stops. Thus, it is possible to suitably extend the thermo-off time while avoiding excessive cooling.

  According to the invention of claim 3, in each of the above-mentioned inventions, when the outside air temperature is higher than a predetermined value, the control device executes the control for increasing the rotational speed of the compressor by the pre-stop temperature. The inconvenience that the evaporator temperature becomes too low can be effectively eliminated.

  According to the invention of claim 4, in each of the above inventions, when the current temperature falls to the pre-stop temperature, the control device normally increases the minimum number of rotations by a predetermined value, so that the control device normally rotates immediately before the compressor stops. The number is often the minimum number of rotations, and the present invention can be implemented smoothly by raising the minimum number of rotations immediately before the compressor stops.

  According to the invention of claim 5, in each of the above inventions, the heat insulating box body in which the storage chamber is configured, the evaporator that forms the refrigeration cycle, and the cold air that exchanges heat with the evaporator is circulated in the storage chamber. It is equipped with a blower and a door that opens and closes the opening of the storage room so that it can be opened and closed. The current temperature is the current temperature of the storage room, and the control device operates the blower while the compressor is stopped. Usually, the temperature detecting means for detecting the current temperature of the storage room is provided at a position where the temperature in the storage room tends to be high, but the fan is operated even when the compressor is stopped, and the temperature in the storage room is uneven. Can be prevented, and the temperature rise in the portion where the temperature detecting means is provided can be suppressed.

  Therefore, as in the above inventions, when cooling is performed to increase the rotational speed immediately before the compressor is stopped, the thermo-off time can be more suitably extended, and the operating rate of the compressor can be lowered to reduce the cumulative consumption. The amount of power can be reduced.

  According to the invention of claim 6, in each of the above-mentioned inventions, the control device, based on the deviation e, performs proportional (P) control, integral (I) control, differential (D) control, proportional integral ( By executing the PI) control, proportional derivative (PD) control, integral derivative (ID), or proportional integral derivative (PID) control, it is possible to realize highly accurate compressor speed control.

It is a vertical side view of the refrigerator as an Example which applies this invention. It is a refrigerant circuit figure of the cooling device of the present invention. It is a block diagram of the control apparatus of the cooling device of this invention. It is a flowchart of the rotation speed increase control of a compressor. It is a timing chart which shows the rotation speed raise control of a compressor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1: has shown the vertical side view of the commercial refrigerator (low temperature storage) R as an Example to which the cooling device 10 of this invention is applied. The refrigerator R of an Example is installed in the kitchen of a hotel, a restaurant, etc., for example, and the main body is comprised by the heat insulation box 1 opened to the front. This heat insulation box 1 is made of polyurethane which is injected, filled and foamed between an outer box 2 made of a steel plate such as stainless steel, an inner box 3 incorporated in the outer box 2, and inner and outer boxes 2, 3. It is comprised from the heat insulating material 4. And the inside of this heat insulation box 1 (inner box 3) is made into the storage chamber 5. FIG.

  In addition, an evaporator 11 of the cooling device 10 according to the present invention is attached to the upper part of the storage chamber 5, and in the vicinity of the evaporator 11, cold air exchanged with the evaporator 11 is placed in the storage chamber 5. A circulating air blower 12 for circulation is attached. Thereby, the inside of the storage chamber 5 is cooled to a predetermined temperature. In the drawing, 13 attached below the evaporator 11 and the blower 12 is a partition plate for partitioning the inside of the cooling chamber 14 and the storage chamber 5 to which the evaporator 11 is attached. A cold air suction port (not shown) is formed facing the cool air circulation blower 12, and the rear is opened. As a result, the cool air sucked from the storage chamber 5 into the cooling chamber 14 by the cool air circulation fan 12 is discharged from the rear of the cooling chamber 14 after heat exchange with the evaporator 11. The front opening 22 of the storage chamber 5 (the heat insulating box 1) is closed so as to be freely opened and closed by two sets of double doors 6.

  On the other hand, a machine room 17 is defined on the top surface of the heat insulation box 1 by a front panel 16 and panels constituting both side faces and a rear face, and a compressor 18 constituting the cooling device 10 is formed in the machine room 17. And a radiator 19 are installed, and together with the evaporator 11, a known refrigeration cycle of the cooling device 10 is configured. Reference numeral 20 denotes a radiator blower.

  Here, the refrigerant circuit 7 of the cooling device 10 in the present embodiment will be described with reference to the refrigerant circuit diagram of FIG. A radiator 19 is connected to the piping 23 on the discharge side of the compressor 18. A capillary tube 25 serving as a decompression unit is connected to the outlet side of the radiator 19 via a pipe 24. The capillary tube 25 is connected to the evaporator 11, and the outlet side of the evaporator 11 is connected to the compressor 18 via a check valve 26 to constitute an annular refrigeration cycle.

  Next, the control device C in the present embodiment will be described with reference to FIG. The control device C is composed of a general-purpose microcomputer and controls the cooling device 10. The control device C includes a timer 32 as a time limit means, a PID calculation processing unit 33, and a storage unit 34. Further, a control panel 35 having various setting switches and a display unit is connected. The various setting switches include an LCD panel (setting means) 36 that can arbitrarily set the set temperature in the storage chamber 5 as will be described in detail later. Further, on the input side of the control device C, an internal temperature sensor (current temperature detection means) 31 for detecting the current temperature in the storage, an outdoor temperature sensor (outside air temperature detection means) 48 for detecting the outdoor temperature, etc. Is connected. Here, the internal temperature sensor 31 is provided at a position where the temperature tends to be highest in the storage chamber 5, for example, in the vicinity of the cold air inlet of the partition plate 13. Thereby, the temperature sensor 31 measures the temperature in the storage chamber 5 before the cold air passes through the evaporator 11 and treats this as the current temperature that is the temperature in the storage chamber 5.

  On the other hand, on the output side of the control device C, a compressor motor (DC motor) 18M that drives the compressor 18, a blower motor 12M that drives the blower 12 for circulating cold air, a blower motor 20M that drives the blower 20 for radiator, and the like. Is connected. Here, the compressor motor 18M is connected via an inverter device 37, whereby the rotational frequency is changed and the rotational speed of the compressor motor 18M is changed to thereby change the circulation amount of the refrigerant in the compressor 18. It can change. And based on each output mentioned above, the control apparatus C is controlling each motor 18M, 12M, and 20M.

  With the above configuration, the cooling control of the refrigerator R in the present embodiment will be described with reference to the flowchart of FIG. 4 and the timing chart of FIG. The control device C detects the temperature in the storage chamber 5, that is, the current internal temperature (current temperature) by the internal temperature sensor 31, and performs cooling based on the current temperature Tp and the target temperature Tt set as described above. Run the operation.

  Here, in the control device C, the temperature detected by the internal temperature sensor 31 (the temperature in the storage chamber 5 as the space to be cooled, hereinafter referred to as the current temperature Tp) is set by the LCD panel 36 of the control panel 35. When a predetermined lower limit temperature Tl (in this embodiment, Tt-2 deg) lower than the target temperature (hereinafter referred to as target temperature Tt) is reached, the compressor 18 is stopped (thermo-off), and the current temperature Tp becomes the target temperature Tt. When the temperature reaches a predetermined upper limit temperature Th higher than (Tt + 2 deg in this embodiment), the compressor 18 is restarted (thermo-on).

  Further, the control device C determines the operating speed of the compressor motor 18M based on the deviation e between the current temperature Tp and the target temperature Tt by the PID arithmetic processing unit 33 provided inside the control device C. Proportional control (P control) is performed by calculating proportional (P) so as to be zero.

That is, based on the deviation e (deviation e = Tp−Tt) between the current temperature Tp and the target temperature Tt, the PID calculation processing unit 33 calculates a proportional amount by multiplying the deviation e by a preset proportional control coefficient Kp. The control amount (inverter rotation speed (frequency) increase / decrease amount “H0”) is calculated by the proportional operation (step S1). Next, it progresses to step S2 and adds the said control amount to the present driving | running rotation speed, and it is set as an operation amount. An arithmetic expression is shown below.
Formula Operation amount = Current operation speed + Control amount
Control amount = (current temperature Tp−target temperature Tt) × Kp

  Next, the control device C proceeds to step S3, and the difference between the current temperature Tp detected by the internal temperature sensor 31 and the lower limit temperature Tl that stops (thermo-off) the compressor 18 is a predetermined temperature difference, for example, It is determined whether or not it has become less than 0.5 deg, that is, whether or not the current temperature Tp has decreased to a predetermined pre-stop temperature Tb close to the lower limit temperature Tl. The pre-stop temperature Tb is at least a temperature lower than the target temperature Tt as described above and higher than a lower limit temperature Tl by a predetermined value (in this embodiment, 0.5 deg, but not limited to the temperature). And

  In step S3, the control device C determines whether or not the outside air temperature Ta detected by the outside air temperature sensor 48 is higher than a predetermined value (for example, + 25 ° C. as a low outside air temperature, which is not limited to this temperature).

  In step S3, if the current temperature Tp is not lowered to the pre-stop temperature Tb or the outside air temperature Ta is lower than the predetermined low outside air temperature even if the current temperature Tp is lowered to the pre-stop temperature Tb, the process goes to step S4. Then, the rotational speed (operating frequency target value) of the motor 18M of the compressor 18 is determined by the operation amount acquired in step S2, and the inverter device 37 rotates the compressor motor 18M so that the rotational speed becomes the rotational speed. Control the number. However, the control device C is configured so that the rotation speed of the compressor motor 18M is between a preset minimum rotation speed (32 Hz in this embodiment) and a maximum rotation speed (60 Hz in this embodiment). Control. That is, when the determined rotational speed of the compressor motor 18M is higher than the maximum rotational speed, the compressor motor 18M is operated at the maximum rotational speed, and when the rotational speed is lower than the minimum rotational speed, the minimum rotational speed is reached. To operate the compressor motor 18M. Such normal cooling control is executed. Thereafter, the control device C detects the current temperature Tp at a predetermined sampling period, and returns to step S1.

  On the other hand, if the current temperature Tp has decreased to the pre-stop temperature Tb in step S3 and the outside air temperature Ta is equal to or higher than the predetermined low outside air temperature, the control device C proceeds to step S5, The set minimum number of revolutions is increased by a predetermined value (for example, 5 Hz), and the process proceeds to step S6.

  In step S6, the control device C determines the rotational speed (operation frequency target value) of the motor 18M of the compressor 18 with the operation amount acquired in step S2, and the inverter device 37 so as to be the rotational speed. Thus, the rotational speed of the compressor motor 18M is controlled. At this time, the control device C determines that the rotation speed of the compressor motor 18M is between a minimum rotation speed (37 Hz in this embodiment) increased by a predetermined value and a maximum rotation speed (60 Hz in this embodiment). Control to be. That is, when the determined rotational speed of the compressor motor 18M is higher than the maximum rotational speed, the compressor motor 18M is operated at the maximum rotational speed, and when the rotational speed is lower than the minimum rotational speed, the minimum rotational speed is reached. To operate the compressor motor 18M.

  Here, in a situation where the current current temperature Tp is normally lowered to the pre-stop temperature Tb close to the lower limit temperature Tl, the deviation becomes negative and the control amount also becomes negative. The number of revolutions of 18M is often the minimum number of revolutions. In this situation, since the minimum rotation speed is increased by a predetermined value in step S6, immediately before the compressor 18 is stopped, the minimum rotation speed in the normal cooling operation in which the operation rotation speed of the compressor motor 18M is set in advance. The engine speed is increased to a predetermined value higher than the number.

  When the current temperature Tp is cooled to the lower limit temperature Tl by the rotation speed control of the compressor 18, the control device C stops the operation of the compressor 18 and increases it by a predetermined value in step S5. The minimum number of revolutions is returned to the preset minimum number of revolutions (that is, the increase by a predetermined value is cleared).

  Further, in the cooling control, the controller C operates the cool air circulation blower 12 even when the compressor motor 18M is operating (thermo on), even when it is stopped (thermo off). Shall. Specifically, in this embodiment, when the compressor motor 18M is operating, the cool air circulation blower 12 is continuously operated, and when the compressor motor 19M is stopped, a predetermined time immediately after the stop, For example, the operation of the air circulation fan 12 is stopped only for 1 minute, and then the continuous operation is performed.

  By controlling as described above, the control device C increases the operating rotational speed of the compressor motor 18M by a predetermined value when the current temperature Tp decreases and decreases to a predetermined pre-stop temperature Tb close to the lower limit temperature Tl. (Normally, the operation at the preset minimum number of revolutions is the operation at the minimum number of revolutions after a predetermined value increase), so that the evaporator 11 can be rapidly cooled immediately before the compressor 18 is stopped (thermo-off). it can. In this embodiment, the cooling control is performed immediately before the compressor is stopped by increasing the minimum rotational speed by a predetermined value. However, the present invention is not limited to this, and the operation amount obtained in step S2 above. Then, the number of rotations of the motor 18M of the compressor 18 may be increased by a predetermined value to perform cooling control immediately before the compressor stops.

  As a result, the thermo-off time from when the compressor 18 is stopped until the current temperature Tp reaches the upper limit temperature Th and the compressor 18 is restarted can be extended, and the operating rate of the compressor 18 can be lowered. It becomes.

  At this time, the rotational speed of the compressor motor 18M is set in advance until the current temperature Tp reaches the lower limit temperature Tl as compared with the case where the operation rotational speed is not increased immediately before the compressor 18 is stopped. Power consumption increases by operating at a predetermined rotational speed higher than the lowest rotational speed, but since the current temperature Tp can be rapidly lowered from the pre-stop temperature Tb to the lower limit temperature Tl, It becomes possible to shorten the thermo-on time itself. Therefore, the operation rate of the compressor 18 can be lowered without increasing the overall power consumption.

  In particular, since the pre-stop temperature Tb that increases the operating speed of the compressor 18 is lower than the target temperature Tt and higher than the lower limit temperature Tl by a predetermined value, the thermo-off time is preferably extended while avoiding excessive cooling. Can be achieved.

  In the present embodiment, as described above, the cool air circulation blower 12 is also operated while the compressor 18 is stopped (thermo-off). Therefore, the internal temperature sensor 31 that detects the current temperature Tp in the storage chamber 5 as in the present embodiment is provided on the suction side of the evaporator 11 where the temperature is most likely to be high in the storage chamber 5. Even when the compressor 18 is stopped, the cool air circulation blower 12 is operated, so that it is possible to prevent the occurrence of temperature unevenness in the storage chamber 5 closed by the door 6, and the internal temperature sensor The temperature rise of the part in which 31 is provided can be suppressed. For this reason, it is possible to eliminate the inconvenience that the compressor 18 is restarted (thermo-on) at an early stage based on the current temperature Tp that is highly detected due to temperature unevenness.

  Therefore, in the case of performing cooling to increase the rotational speed immediately before the compressor 18 is stopped, it is possible to more suitably extend the thermo-off time, lower the operating rate of the compressor 18 and reduce the integrated power consumption. Can be achieved.

  Furthermore, in the present embodiment, in step S3, the control device C executes the rotation speed increase control of the compressor 18 by the pre-stop temperature Tb only when the outside air temperature Ta is higher than a predetermined value. By causing the rotation speed increase control of the compressor 18 to be executed until Ta is low, it is possible to effectively avoid the disadvantage that the temperature of the evaporator 11 decreases excessively.

  In the present embodiment, the control device C proportionally controls the compressor motor 18M based on the deviation e. However, the present invention is not limited to this, and may be proportional integral derivative (PID) control. In this case, the PID calculation processing unit 33 calculates a proportional amount by multiplying the deviation e by a proportional control coefficient based on the deviation e between the current temperature Tp and the target temperature Tt, and an integral value (cooling) of the deviation e. The integral operation to calculate the integral amount by multiplying the deviation e from the target temperature e in the time axis direction) by the integral control coefficient, and the differential control coefficient to the differential value of the deviation e (inclination of the temperature change in the chamber) Then, the rotational speed (operation frequency) of the motor 18M of the compressor 18 is determined from the operation amount obtained by adding the control amount calculated by the combination of the differential operations for calculating the differential amount to the current operation rotational speed. Thereby, the precision of internal temperature control can be raised more.

  In addition to this, the proportional coefficient Kp used for calculating the proportional quantity, the integral (I) control with the differential coefficient Kd used for calculating the differential quantity being zero, the proportional coefficient, and the integral coefficient used for calculating the integral quantity. Perform differential (D) control with Ki as zero, proportional integral (PI) control with zero differential coefficient, proportional differential (PD) control with zero integral coefficient, integral differential (ID) with zero proportional coefficient Even in this case, the present invention is effective.

R Commercial refrigerator (low temperature storage)
C Control Device 1 Heat Insulation Box 5 Storage Room 7 Refrigerant Circuit 10 Cooling Device 11 Evaporator 12 Blower for Cooling Air Circulation 12M Blower Motor 18 Compressor 18M Compressor Motor 25 Capillary Tube (Decompression Unit)
31 Internal temperature sensor (current temperature detection means)
33 PID processing unit 37 Inverter device 48 Outside temperature sensor (outside temperature detecting means)

Claims (6)

In the cooling device provided with a control device for controlling the rotation speed of the compressor constituting the refrigeration cycle,
The control device controls the rotation speed of the compressor based on a deviation e between the current temperature and the target temperature within a range between a predetermined maximum rotation speed and a minimum rotation speed so as to make the deviation e zero.
When the current temperature falls to a predetermined lower limit temperature lower than the target temperature, the compressor is stopped,
The cooling device according to claim 1, wherein when the current temperature is reduced to a predetermined pre-stop temperature close to the lower limit temperature, the rotation speed of the compressor is increased by a predetermined value.   The cooling device according to claim 1, wherein the pre-stop temperature is lower than the target temperature and higher than the lower limit temperature by a predetermined value.   3. The cooling device according to claim 1, wherein the control device executes a rotation speed increase control of the compressor based on the pre-stop temperature when an outside air temperature is higher than a predetermined value.   4. The cooling device according to claim 1, wherein the control device increases the minimum number of rotations by a predetermined value when the current temperature decreases to the pre-stop temperature. 5. . A heat insulating box having a storage chamber therein, an evaporator constituting the refrigeration cycle, a blower for circulating cold air exchanged with the evaporator into the storage chamber, and opening of the storage chamber being freely openable With a closing door,
The current temperature is a current temperature of the storage room, and the control device operates the blower while the compressor is stopped. The cooling apparatus in any one of.   The control device, based on the deviation e, proportional (P) control, integral (I) control, differential (D) control, proportional integral (PI) control, proportional differential (PD) control of the rotation speed of the compressor, The cooling apparatus according to any one of claims 1 to 5, wherein integral derivative (ID) or proportional integral derivative (PID) control is executed.

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