JP2012078077A - Refrigerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerating device capable of keeping a temperature of a condenser optimum and capable of saving energy.SOLUTION: The refrigerating device includes: a refrigerating cycle comprising a sequence of a compressor 32, a condenser 33, a throttle valve device and an evaporator 34; a condenser fan motor 33C driving at variable speeds a condenser fan 33B that cools the condenser body 33A; a condenser temperature sensor 33D detecting the temperature of the condenser body 33A; and a rotational speed control means controlling the rotational speed of the condenser fan motor 33C on the basis of a measured value Tc detected by the condenser temperature sensor 33D. The rotational speed control means has a function of increasing the rotational speed of the condenser fan motor 33C when a measured value Tc over a predetermined first reference T1 in an upper limit side is continued for a prescribed time, and decreasing the rotational speed of the condenser fan motor 33C when a measured value Tc lower than a predetermined second reference T2 in a lower limit side is continued for a prescribed time.

Description

  The present invention relates to a refrigeration apparatus having a condenser fan motor that drives a condenser fan at a variable speed.

  This type of refrigeration apparatus is widely used in cooling storages such as refrigerators, vending machines, ice makers, air conditioners, etc., and its basic configuration is, for example, a throttle valve device such as a compressor, a condenser, a capillary tube, etc. It consists of a refrigeration cycle in which the evaporator is connected in order by the refrigerant circuit, and the refrigerant in the refrigerant circuit is compressed by the compressor, dissipated by the condenser, and evaporated by the evaporator to produce a cooling action. is there.

  The condenser used in such a refrigeration apparatus includes a condenser fan that cools the refrigerant discharged from the compressor and becomes superheated steam by blowing air, and among these, the rotation of the condenser fan motor that drives the condenser fan The thing of patent document 1 is known as what controlled the speed variably. In this device, the rotation speed of the condenser fan motor is determined according to the condenser temperature, and energy is saved by performing appropriate air blowing with no excess or deficiency according to the condenser temperature.

JP 2004-44868 A

  However, according to such a configuration, since the rotational speed of the condenser fan motor is determined according to the instantaneous value of the condenser temperature, unnecessary rotational speed changes may frequently occur. In particular, in a device in which the heat load of the refrigeration cycle is likely to change suddenly, for example, a refrigerator, the internal temperature changes rapidly due to opening and closing of the refrigerator door, so it is assumed that the rotation speed of the condenser fan motor changes frequently. .

  That is, when the door is opened and the internal temperature rises, the heat load of the refrigeration cycle increases to approach the set temperature of the storage chamber, and the condenser temperature rises. As a result, the rotational speed of the condenser fan motor increases rapidly according to the condenser temperature. Subsequently, when the door is closed and the internal temperature is returned to the original temperature again, a high cooling capacity is not required, so that the heat load of the refrigeration cycle and the condenser temperature immediately return to the original state. Then, the rotational speed of the condenser fan motor is also immediately changed to the original rotational speed according to the condenser temperature.

  If the rotational speed of the condenser fan motor is frequently changed in this way, the power consumption by the condenser fan motor increases, which may reduce the energy saving effect. Also, if the rotational speed of the condenser fan (motor) is changed frequently, the condenser temperature may not be maintained at an optimum temperature. For example, if the heat load of the refrigeration cycle becomes excessive, the coefficient of performance will be small. As a result, power is wasted.

  The present invention has been completed based on the above circumstances, and in a refrigeration apparatus having a condenser fan motor that drives a condenser fan at a variable speed, the condenser temperature is optimally maintained and energy saving is possible. An object of the present invention is to provide a simple refrigeration apparatus.

  In the present invention, a compressor, a condenser, a throttle valve device, and an evaporator are connected in order, and a refrigerant is compressed by the compressor, radiated by the condenser, and evaporated by the evaporator to produce a cooling action. A condenser fan motor that drives the condenser fan that cools the condenser at a variable speed, a condenser temperature sensor that detects the temperature of the condenser, and a measurement value detected by the condenser temperature sensor. A rotation speed control means for controlling the rotation speed of the condenser fan motor based on the first reference value on the upper limit side where the measurement value is preset. When the state of exceeding is continued for a predetermined time, the rotational speed of the condenser fan motor is increased, and the state where the measured value is lower than the preset second reference value on the lower limit side is continued for a predetermined time. The characterized in that it has a function of reducing the rotational speed of the condenser fan motor.

  According to such a configuration, the rotational speed of the condenser fan motor is determined based on the condenser temperature, and when the measured value of the condenser temperature exceeds the first reference value on the upper limit side for a predetermined time, If the rotation speed of the condenser fan motor is increased and falls below the second reference value on the lower limit side for a predetermined time, the rotation speed of the condenser fan motor is decreased. Energy consumption can be reduced by reducing the power consumption due to the change. Conventionally, by controlling the rotation speed of the condenser fan motor when the desired condenser temperature range is exceeded, it is possible to control the condenser fan motor efficiently while maintaining the condenser temperature at an optimum temperature. Has been made.

  However, in a refrigeration apparatus that easily changes the heat load state of the refrigeration cycle, such as a cooling storage, the conventional control method described above changes the rotational speed of the condenser fan motor according to the instantaneous value of the condenser temperature, and thus the short-term The rotational speed of the condenser fan motor depends on the change in the heat load state of the refrigeration cycle, and unnecessary rotational speed changes are frequently repeated. As a result, the amount of power consumption has increased and the energy saving effect has been inevitably reduced.

  On the other hand, the present invention increases or decreases the rotational speed when the state exceeding the first reference value or the state falling below the second reference value continues for a predetermined time. Without being confused by the descent, an unnecessary change in the rotational speed of the condenser fan motor can be suppressed and energy saving can be realized. Moreover, since the change in the sound pressure of the wind noise of the condenser fan that occurs due to frequent changes in the rotational speed of the condenser fan motor can be suppressed, it is possible to reduce the discomfort caused by the noise of the user.

  It has been known that the rotational speed of the condenser fan motor is changed according to the condenser temperature. However, in this case, the rotational speed of the condenser fan motor is set so as to be within a desired condenser temperature range. Since the rotational speed of the condenser fan motor is determined by the instantaneous value of the condenser temperature at that time instead of being determined, the condenser temperature is not necessarily optimized. In other words, if the rotational speed of the condenser fan motor is determined by being confused by the instantaneous value of the condenser temperature, the rotational speed of the condenser fan motor may be excessive or insufficient with respect to the heat load state of the refrigeration cycle. As a result, the condenser temperature may not be optimized.

  On the other hand, the present invention determines the first reference value that is the upper limit value and the second reference value that is the lower limit value, and changes the condenser fan motor rotational speed when it is out of this range. The temperature can be kept optimal. In addition, by keeping the condenser temperature optimal in this way, it is possible to suppress an increase in the refrigerant pressure on the high pressure side of the refrigeration cycle, thereby reducing the heat load on the compressor, and thus the long life of the entire refrigeration system. Can also be achieved.

  The rotation speed control means sets the rotation speed of the condenser fan motor to a preset maximum rotation speed when the measured value exceeds a third reference value higher than the preset first reference value. You may have the function to change. If the condenser temperature rises so rapidly that it exceeds a third reference value that is higher than the first reference value, it waits for a predetermined time to continue exceeding the first reference value, and then gradually the rotational speed of the condenser fan motor When waiting for the temperature to rise, there is a possibility that the heat load of the refrigeration cycle increases and the power consumption increases due to insufficient cooling of the condenser during that time. In addition, even if the condenser is simply insufficiently cooled, it may be regarded as a high-pressure abnormality in the refrigeration cycle, and the refrigeration apparatus including the compressor may be urgently stopped.

  On the other hand, if the measured value of the condenser temperature exceeds the third reference value, the rotation speed of the condenser fan motor is increased without waiting for the increase in the rotation speed of the condenser fan motor due to the first reference value. By changing to the maximum rotation speed, an increase in power consumption due to an insufficient air volume can be suppressed and energy saving can be achieved. Further, energy saving can be achieved by preventing the condenser from being insufficiently cooled and suppressing the occurrence of high-pressure abnormality.

  The rotational speed control means may have a function of maintaining the rotational speed of the condenser fan motor when the measured value is between the first reference value and the second reference value. . According to such a configuration, when the condenser temperature is between the desired first reference value and the second reference value, the rotation speed of the condenser fan motor is maintained without being changed unnecessarily. No power is generated for changing the rotation speed, and further energy saving can be achieved.

  An integration timer for integrating the time since the rotation speed of the condenser fan motor is changed, and the rotation speed control means is configured to adjust the time until the time integrated by the integration timer reaches a predetermined time. You may have the function which prohibits the change of a rotational speed.

  Depending on the capacity of the condenser fan motor and the length of each predetermined time, for example, even if the rotational speed of the condenser fan motor is changed, the condenser temperature immediately falls between the first reference value and the second reference value. If it does not fall within the range, there is a possibility that the rotation speed is repeatedly changed every predetermined time. On the other hand, the present invention suppresses the occurrence of so-called chattering by prohibiting the change of the rotation speed of the condenser fan motor until the effect is exhibited after the change of the rotation speed of the condenser fan motor. The rotational speed of the fan motor can be stabilized. In this way, by further suppressing the change in rotational speed more frequently than necessary for the condenser fan motor, further energy saving can be achieved while optimizing the condenser temperature.

  The rotational speed of the condenser fan motor is set to be variable over a plurality of stages, and the rotational speed control means is configured so that the state where the measured value exceeds the first reference value continues for a predetermined time. A function to increase the rotation speed of the condenser fan motor by one step and to decrease the rotation speed of the condenser fan motor by one step when the measured value falls below the second reference value for a predetermined time. Also good. By changing the rotational speed of the condenser fan motor in stages, the rotational speed of the condenser fan motor can be optimized according to the capacity of the condenser fan or the scale of the refrigeration cycle. Therefore, it is possible to reduce power consumption and realize energy saving.

  ADVANTAGE OF THE INVENTION According to this invention, in the refrigerating apparatus which has a condenser fan motor which drives a condenser fan at variable speed, the refrigerating apparatus which can maintain condenser temperature optimal and can save energy can be provided.

The front view of the cooling storehouse which concerns on Embodiment 1 of this invention Same longitudinal section Block diagram showing control mechanism of condenser fan motor Table that summarizes the correspondence between the number of setting stages and the rotational speed of the condenser fan motor Flowchart showing the rotational speed control operation of the condenser fan motor 7 is a flowchart showing the rotational speed control operation of the condenser fan motor according to the second embodiment. 9 is a flowchart showing the rotational speed control operation of the condenser fan motor according to the third embodiment.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS.
In this embodiment, the case where the refrigeration apparatus of the present invention is applied to a commercial refrigerator-freezer is illustrated. First, the entire structure will be described with reference to FIGS. 1 and 2. The refrigerator-freezer is a four-door type, and includes a main body 10 formed of a heat-insulating box having an open front surface. A heat insulating partition frame 12 assembled in a cross shape is attached to the front opening of the storage chamber 11 to form four entrances 13, and a double-spread type heat insulating door 14 is attached in two upper and lower stages. ing.

  A machine room 20 is provided on the upper surface of the main body 10 by being surrounded by a panel, and an opening 21 having a square shape in plan view is formed on the upper surface of the main body 10 which is the bottom surface of the machine room 20. A drain pan 22 that also serves as an air duct is stretched below the opening 21. Specifically, the drain pan 22 is mounted so as to have a downward slope toward the back side of the storage chamber 11 (the right side in FIG. 2). A suction port 22A is formed in the area on the front side (left side in FIG. 2), and an outlet 22B is formed in the area on the back side.

  Now, the machine room 20 accommodates a refrigeration apparatus 30 that is unitized with a unit base 31 disposed so as to close the opening 21 from above. The refrigeration apparatus 30 includes a refrigeration cycle in which a compressor 32, a condenser 33, a dryer (not shown), a capillary tube corresponding to a throttle valve device, and an evaporator 34 are sequentially connected by refrigerant piping. This refrigeration cycle is a well-known configuration in which the refrigerant in the refrigerant pipe is compressed by the compressor 32, dissipated by the condenser 33, and evaporated by the evaporator 34 to produce a cooling action.

  In the refrigeration cycle, a compressor 32 and a condenser 33 are placed on the unit table 31, and an evaporator 34 is accommodated in an evaporator chamber 23 below the unit table 31 and partitioned by the drain pan 22. Yes. In addition, the evaporator chamber 23 is equipped with a cooling fan 35 that faces the suction port 22A. The internal air in the storage chamber 11 circulates in the direction of the arrow shown in FIG. 2. Specifically, the internal air sucked into the evaporator chamber 23 from the suction port 22A by the cooling fan 35 evaporates. It cools by performing heat exchange with the container 34, and is then blown out again into the storage chamber 11 from the blowout port 22B, whereby the cooled internal air is circulated and supplied into the storage chamber 11. Note that an inside thermistor (not shown) is provided on the suction port 22A side of the evaporator chamber 23, and the operation of the refrigeration apparatus 30 is performed according to the temperature in the storage chamber 11 detected by the inside thermistor. The stop is controlled, and the temperature in the storage chamber 11 is maintained at a predetermined target temperature.

  Next, the configuration of the condenser 33 will be described. As shown in FIG. 2, the condenser 33 is a well-known condenser main body 33 </ b> A composed of a heat transfer tube and fins, and a condenser fan that blows air to the condenser main body 33 </ b> A and cools the refrigerant in the heat transfer tube by air cooling. 33B and a condenser fan motor 33C that drives the condenser fan 33B. The condenser fan motor 33C can control the rotational speed of the condenser fan 33B in a plurality of stages. For example, a DC brushless motor is used. Although not shown, a condenser thermistor 33D for detecting the temperature of the condenser body 33A is attached to the center of the condenser body 33A, and the condenser fan motor 33C is connected to the condenser thermistor 33D. The speed is controlled according to the thermistor temperature Tc.

  For controlling the condenser fan motor 33C, a control unit 50 having a microcomputer (not shown) is provided (see FIG. 3). The control unit 50 corresponds to the rotational speed control means of the present invention. A condenser thermistor 33D for detecting the condenser thermistor temperature Tc is connected to the input side, and a condenser fan motor 33C is connected to the output side. Has been. The control unit 50 is linked to a separately provided control circuit for the compressor 32. When the control circuit for the compressor 32 is in operation, power is also supplied to the control unit 50 and the condenser fan motor 33C. The control instruction signal of the condenser fan motor 33C is output from the control circuit of the compressor 32 so as to synchronize with the operation of the compressor 32.

  The control unit 50 is provided with a reference value comparison unit 51, which stores a first reference value T1 and a second reference value T2 set in advance. The first reference value T1 is the upper limit value of the optimum temperature range of the condenser thermistor temperature Tc, and is 42 ° C. here. The second reference value T2 is also the lower limit value of the optimum temperature range of the condenser thermistor temperature Tc, and is 39 ° C. here. The reference value comparison unit 51 reads a signal from the condenser thermistor 33D and compares the input value of the condenser thermistor temperature Tc with the first reference value T1 and the second reference value T2.

  For example, when the first reference value is exceeded, the duration of the exceeded state is counted, and when it reaches, for example, 10 seconds, the set stage number corresponding to the rotational speed of the condenser fan motor 33C shown in FIG. Referring to the output, the set number of stages of the condenser fan motor 33C is increased by one stage from the set number of stages at that time. In addition, when the value falls below the second reference value T2, the duration of the lowered state is counted, and when it reaches, for example, 10 seconds, with reference to the set number of stages in FIG. The setting stage number is output so as to be one stage lower than the setting stage number at that time. When the condenser thermistor temperature Tc is between the first reference value T1 and the second reference value T2, the output is performed so as to maintain the set number of stages of the condenser fan motor 33C.

  Next, the operation of this embodiment will be described with reference to FIG. During operation of the refrigerator-freezer, the controller 50 of the condenser fan motor 33C always determines whether or not there is an operation instruction for the condenser fan motor 33C (step S10), so the temperature in the refrigerator-freezer increases. When the operation of the compressor 32 is started and the operation instruction signal for the condenser fan motor 33C is output, the operation of the condenser fan motor 33C is immediately started ("YES" in step S10). In addition, the rotation speed of the condenser fan motor 33C is started from a predetermined number of steps. When the temperature in the storage chamber 11 rises during a so-called pull-down operation immediately after the refrigerator is turned on, immediately after an object to be cooled is inserted into the storage chamber 11, or when the heat insulating door 14 is frequently opened and closed, the heat of the refrigeration cycle The load increases and the condenser thermistor temperature Tc exceeds the first reference value T1 (42 ° C. here) (step S12 is “YES”).

  Among these, during the pull-down operation or immediately after the object to be cooled is put into the storage chamber 11, the heat load of the refrigeration cycle is maintained high, and the condenser thermistor temperature Tc is the first reference. The state exceeding the value T1 reaches 10 seconds (“YES” in step S13), and the set number of steps (see FIG. 4) corresponding to the rotation speed of the condenser fan motor 33C is increased by one step (step S14). For example, when the setting stage number of the condenser fan motor 33C at that time is 2 and the rotation speed is R2, the setting stage number is increased to 3, and the rotation speed is R3.

  On the other hand, when the internal temperature temporarily rises due to the opening and closing of the heat insulating door 14 and the thermal load of the refrigeration cycle temporarily rises, the condenser thermistor temperature Tc temporarily exceeds the first reference value T1. Therefore, the duration does not reach 10 seconds (“NO” in step S13). Since it is not necessary to change the rotational speed of the condenser fan motor 33C in accordance with the change in the heat load state of the refrigeration cycle in such a short period, the current rotational speed is continuously maintained (step S18). .

  On the contrary, when the temperature in the storage chamber 11 is lower than the set temperature and no further cooling is required, that is, the heat load of the refrigeration cycle is low, and the rotational speed of the condenser fan motor 33C becomes excessive. In this case, the condenser thermistor temperature Tc is lower than the second reference value T2 (here, 39 ° C.) (step S15 is “YES”), and its duration reaches 10 seconds (step S16 is “YES”). "). Then, the set stage number (see FIG. 4) corresponding to the rotation speed of the condenser fan motor 33C is lowered by one stage (step S17). For example, when the set stage number of the condenser fan motor 33C at that time is 2 and the rotational speed is R2, the set stage number is reduced to 1, and the rotational speed is R1.

  On the other hand, when the heat load of the refrigeration cycle temporarily decreases, the state where the condenser thermistor temperature Tc is lower than the second reference value T2 does not reach 10 seconds (“NO” in step S16). Since it is not necessary to change the rotation speed of the condenser fan motor 33C in accordance with the change in the heat load state of the refrigeration cycle in such a short period, the current rotation speed of the condenser fan motor 33C is continuously maintained ( Step S18).

  As described above, according to the present embodiment, the rotational speed of the condenser fan motor 33C is determined based on the condenser thermistor temperature Tc detected by the condenser thermistor 33D, and the condenser thermistor temperature Tc is the first reference. When the state exceeding the value T1 continues for 10 seconds, the set number of steps corresponding to the rotation speed of the condenser fan motor 33C increases by one step, and when the state below the second reference value T2 continues for 10 seconds, Since the set number of steps corresponding to the rotation speed of the condenser fan motor 33C is lowered by one, the power consumption due to frequent changes in the rotation speed of the condenser fan motor 33C can be suppressed, and energy saving can be realized. .

  That is, instead of changing the rotational speed of the condenser fan motor 33C based on the instantaneous value of the condenser thermistor temperature Tc, a state in which a predetermined condition is satisfied for each of the reference values T1 and T2 is continued for a predetermined time. By changing the rotational speed of the condenser fan motor 33C after waiting for, for example, the heat insulation door 14 of the refrigeration refrigerator is frequently opened and closed, and even if the heat load state of the refrigeration cycle changes in a short time, It is possible to save energy by suppressing an unnecessary change in the rotational speed of the condenser fan motor 33C. In addition, since the change in the sound pressure of the wind noise of the condenser fan 33B that occurs due to frequent changes in the rotational speed of the condenser fan motor 33C can be suppressed, the user's discomfort due to noise can be reduced.

  Further, when the optimum temperature range (the first reference value T1 to the second reference value T2) of the condenser body 33A is determined and the state outside the range continues for a predetermined time, the rotation speed of the condenser fan motor 33C is changed. By doing so, the temperature of the condenser body 33A can be kept optimal. That is, the optimum temperature range of the condenser thermistor temperature Tc is not set, and each rotational speed corresponding to each condenser thermistor temperature Tc is set. Depending on the condenser thermistor temperature Tc, each time the condenser fan motor 33C is When the rotational speed is changed, not only the power consumption increases, but the rotational speed of the condenser fan motor 33C may be excessive or insufficient with respect to the heat load state of the refrigeration cycle. As a result, the condenser Not only is the temperature of the main body 33A not optimized, but also the heat load state of the refrigeration cycle is not optimized. In order to avoid such a situation and control the rotational speed of the condenser fan motor 33C as described above in this embodiment, an increase in the refrigerant pressure on the high-pressure side of the refrigeration cycle is suppressed, and thereby the heat load applied to the compressor 32 As a result, the life of the entire refrigerator-freezer can be extended.

  Further, when the condenser thermistor temperature Tc is between the first reference value T1 and the second reference value T2, the rotation speed of the condenser fan motor 33C is maintained. ) Is not changed, and the power necessary for the change is not generated, so that further energy saving can be achieved. It should be noted that the number of rotations of the condenser fan motor 33C is determined in advance according to the number of stages set over a plurality of stages as shown in FIG. The program can be simplified. Further, the rotation speed of the condenser fan motor 33C can be optimized according to the capacity of the condenser fan 33B or according to the scale of the refrigeration cycle, thereby suppressing power consumption and saving energy. It is possible to plan.

<Embodiment 2>
Next, Embodiment 2 of the present invention will be described with reference to FIG.
This embodiment is different from the first embodiment in that a third reference value T3 higher than the first reference value T1 is provided, and control when the condenser thermistor temperature Tc exceeds the third reference value T3. The control of the rotational speed of the condenser fan motor 33C by the unit 50 is different. Since other configurations are the same as those of the first embodiment, the same portions are denoted by the same reference numerals and redundant description is omitted.

  The reference value comparison unit 51 of the control unit 50 stores a first reference value T1, a second reference value T2, and a third reference value T3 that are set in advance. The third reference value T3 is a high temperature value that requires the temperature of the condenser main body 33A to be rapidly reduced, and is set to 48 ° C. in the present embodiment. The reference value comparison unit 51 reads a signal from the condenser thermistor 33D, and compares the input value with the condenser thermistor temperature Tc and the reference values T1, T2, and T3. When the value exceeds the third reference value T3, output is performed so as to change the maximum number of stages with reference to the set number of stages corresponding to the rotation speed of the condenser fan motor 33C.

  Next, the operation of this embodiment will be described with reference to FIG. As in the first embodiment, the temperature in the refrigerator / refrigerator rises and the operation of the compressor 32 is started, and the operation instruction signal of the condenser fan motor 33C is output, and the operation of the condenser fan motor 33C is immediately started. (Step S10 is “YES”). When the temperature of the condenser main body 33A (condenser thermistor temperature Tc) reaches the temperature (third reference value T3) at which it quickly cools (step S20 is “YES”), the setting corresponding to the rotational speed of the condenser fan motor 33C. The number of stages is changed to the maximum number of stages (step S21), and the condenser main body 33A is rapidly cooled by the condenser fan 33B having the maximum rotation speed.

  As described above, according to the present embodiment, the reference value comparison unit 51 is provided with the third reference value T3 higher than the first reference value T1, and the condenser thermistor temperature Tc is determined to be equal to or higher than the third reference value T3. In this case, since the rotation speed of the condenser fan motor 33C is immediately changed to the maximum value, it is possible to cope with a rapid temperature rise of the condenser main body 33A. That is, waiting for the state where the condenser thermistor temperature Tc exceeds the first reference value T1 continues for 10 seconds, and further waiting for the set number of stages to increase one by one, the cooling of the condenser main body 33A during that time is insufficient. As a result, the heat load of the refrigeration cycle increases and the power consumption may increase. In addition, even if the cause of the condenser thermistor temperature Tc being equal to or higher than the third reference value T3 is simply insufficient cooling of the condenser body 33A, the compressor 32 can be regarded as a high pressure abnormality in the refrigeration cycle. In some cases, the refrigeration apparatus 30 including the emergency stop may be stopped in an emergency.

  In this embodiment, when the condenser thermistor temperature Tc is equal to or higher than the third reference value T3, the rotational speed of the condenser fan motor 33C is immediately changed to the maximum number of stages (maximum rotational speed), as described above. It is possible to save energy by suppressing an increase in power consumption due to a shortage of air flow and suppressing the occurrence of high pressure abnormality.

<Embodiment 3>
Next, Embodiment 3 of the present invention will be described with reference to FIG.
In this embodiment, in addition to the second embodiment, the control unit 50 is provided with an integration timer that integrates the time since the rotation speed of the condenser fan motor 33C is changed. The difference is that a step of whether or not the predetermined time reaches a predetermined time is added. Since other configurations are the same as those of the second embodiment, the same portions are denoted by the same reference numerals and redundant description is omitted.

  In addition to the reference value comparison unit 51, the control unit 50 is provided with an integration timer (not shown) that integrates the time since the rotation speed of the condenser fan motor 33C is changed. After determining whether or not the condenser thermistor temperature Tc is equal to or higher than the third reference value T3, if it is equal to or lower than the third reference value T3, the same as in the first embodiment until the time accumulated by this accumulation timer reaches 10 seconds. The control by the reference value comparison unit 51 is prohibited, and the change of the rotation speed of the condenser fan motor 33C is prohibited.

  Next, the operation of this embodiment will be described with reference to FIG. Similarly to the second embodiment, the operation of the condenser fan motor 33C is started (step S10 is “YES”), and the temperature of the condenser body 33A (condenser thermistor temperature Tc) is rapidly cooled (third reference value). When T3) is reached ("YES" in step S20), the set stage number corresponding to the rotational speed of the condenser fan motor 33C is changed to the maximum stage number (step S21), and the condenser main body 33A has the maximum rotational speed. It is cooled rapidly by the condenser fan 33B.

  When it is not necessary to cool the condenser main body 33A immediately (step S20 is “NO”), until 10 seconds or more have elapsed since the rotation speed of the condenser fan motor 33C was changed last time (step S30 is “ NO ") The current rotational speed of the condenser fan motor 33C is maintained (step S18). When 10 seconds have elapsed since the rotation speed of the condenser fan motor 33C was changed ("YES" in step S30), the same control as in the first and second embodiments is performed.

  As described above, according to the present embodiment, the control unit 50 is provided with the integration timer that integrates the time since the rotation speed of the condenser fan motor 33C is changed, and the time accumulated by the integration timer is 10 times. Since the change of the rotation speed of the condenser fan motor 33C is prohibited until more than one second elapses, so-called chattering of the condenser fan motor 33C can be suppressed, and the rotation speed of the condenser fan motor 33C can be further stabilized. it can.

  More specifically, for example, when the detected state where the condenser thermistor temperature Tc has deviated from a range between the first reference value T1 and the second reference value T2 that is the optimum temperature range of the condenser body 33A continues for a predetermined time. In this case, even if the rotational speed of the condenser fan motor 33C is changed, the temperature of the condenser body 33A may not immediately fall within the optimum temperature range. In such a case, it is assumed that the change of the set stage number corresponding to the rotation speed is repeated every time the state exceeding the first reference value T1 or the state below the second reference value T2 is continued for 10 seconds. .

  Assuming such a situation, in the present embodiment, unless the condenser thermistor temperature Tc, which requires the temperature of the condenser main body 33A to be quickly reduced, becomes equal to or higher than the third reference value T3, After the change of the rotation speed of the condenser fan motor 33C, the change of the rotation speed of the condenser fan motor 33C is prohibited until the effect is exhibited. In this way, by further suppressing the change in rotational speed more frequently than necessary for the condenser fan motor 33C, further energy saving can be achieved while optimizing the temperature of the condenser main body 33A.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) In each of the above-described embodiments, the refrigeration apparatus of the present invention has been described with reference to an example in which the refrigeration apparatus is applied to a commercial refrigerator-freezer. However, the present invention is not limited to this example. And may be widely applied to a refrigerant compression type refrigeration apparatus.

  (2) In each of the above-described embodiments, in a state where the detected condenser thermistor temperature Tc falls between the first reference value T1 and the second reference value T2, the rotational speed of the condenser fan motor Tc is at that time. However, the present invention is not limited to this. For example, in a state where the condenser thermistor temperature Tc falls between the first reference value T1 and the second reference value T2, a preset function is set. The rotational speed is changed with reference to the above, or a predetermined rotational speed is given to a predetermined range of the condenser thermistor temperature, and the rotational speed of the condenser fan motor is changed for each range. Good.

  (3) In each above-mentioned embodiment, although the condenser thermistor which detects a condenser temperature was attached to the condenser center, it is not restricted to this, For example, you may attach to the outlet piping of the condenser.

  (4) In each of the above-described embodiments, the first reference value T1 is 42 ° C. and the second reference value T2 is 39 ° C. However, the present invention is not limited to this, and the scale of the condenser and the refrigeration cycle including it is necessary. It shall be changed as appropriate according to the capability.

  (5) In Embodiment 2 and Embodiment 3 described above, the third reference value T3 was set to 48 ° C., but is not limited to this, and the scale of the condenser and the refrigeration cycle including it, and the required capacity. It shall be changed accordingly.

  (6) In each embodiment described above, each predetermined time is set to 10 seconds. However, the predetermined time is not limited to this, and can be appropriately changed according to the scale and capacity of the condenser and the refrigeration cycle including the condenser.

DESCRIPTION OF SYMBOLS 10 ... Main body 11 ... Storage room 12 ... Partition frame 13 ... Entrance / exit 14 ... Heat insulation door 20 ... Machine room 21 ... Opening part 22 ... Drain pan 22A ... Inlet 22B ... Outlet 23 ... Evaporator room 30 ... Refrigeration device 31 ... Unit stand 32 ... Compressor 33 ... Condenser 33A ... Condenser main body 33B ... Condenser fan 33C ... Condenser fan motor 33D ... Condenser thermistor (condenser temperature sensor) 34 ... Evaporator 35 ... Cooling fan 50 ... Control part 51 ... Reference | standard Value comparison unit T1 ... first reference value T2 ... second reference value T3 ... third reference value Tc ... condenser thermistor temperature (measured value)

Claims (5)

A refrigeration cycle in which a compressor, a condenser, a throttle valve device, and an evaporator are connected in order, and a refrigerant is compressed by the compressor and radiated by the condenser, and evaporated by the evaporator, thereby generating a cooling action;
A condenser fan motor that drives a condenser fan that cools the condenser at a variable speed;
A condenser temperature sensor for detecting the temperature of the condenser;
A rotational speed control means for controlling a rotational speed of the condenser fan motor based on a measurement value detected by the condenser temperature sensor, and a refrigeration apparatus comprising:
The rotational speed control means increases the rotational speed of the condenser fan motor when the measured value exceeds the preset first reference value on the upper limit side for a predetermined time, and the measured value is A refrigerating apparatus having a function of reducing the rotational speed of the condenser fan motor when a state below a set second reference value on a lower limit side continues for a predetermined time.   The rotation speed control means sets the rotation speed of the condenser fan motor to a preset maximum rotation speed when the measured value exceeds a third reference value higher than the preset first reference value. The refrigeration apparatus according to claim 1, which has a function of changing.   The rotational speed control means has a function of maintaining the rotational speed of the condenser fan motor when the measured value is between the first reference value and the second reference value. The refrigeration apparatus according to claim 1 or 2. An integration timer for integrating the time since the rotation speed of the condenser fan motor is changed,
4. The rotation speed control means has a function of prohibiting a change in the rotation speed of the condenser fan motor until the time accumulated by the accumulation timer reaches a predetermined time. The refrigeration apparatus according to any one of the above. The rotational speed of the condenser fan motor is set to be variable over a plurality of stages,
The rotational speed control means increases the rotational speed of the condenser fan motor by one step when the measured value exceeds the first reference value for a predetermined time, and the measured value becomes the second reference value. The refrigerating apparatus according to any one of claims 1 to 4, further comprising a function of reducing the rotational speed of the condenser fan motor by one step when the lowering state continues for a predetermined time.

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