JP2010071609A - Open showcase - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an open showcase allowing stable execution of energy-saving operation when an opening is blocked with a night cover. <P>SOLUTION: The open showcase 1 discharging cold air to the opening 12 of a storage chamber 11 by internal fans 27, 28 to cool the inside of the storage chamber 11 while forming a cold air curtain, and comprising the night cover 51 for covering the opening 12, includes a lighting device 36 for illuminating the inside of the storage chamber 11; a temperature sensor 22 inside the storage chamber 11; and a control device 20. When the lighting device 20 is put out, the control device 20 carries out predetermined energy-saving operation including control of raising the set temperature in the storage chamber 11 on condition that the temperature in the storage chamber 11 detected by the temperature sensor 22 is stable. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention cools the storage chamber while discharging cold air heat-exchanged with the cooler by the internal fan to the opening of the storage chamber to form a cold air curtain, and has an open show with a night cover covering the opening. The case is particularly related to energy-saving operation at night or when the store is closed.

  Conventionally, showcases installed in stores such as supermarkets and convenience stores have been formed with storage rooms for displaying products inside, and the storage rooms are composed of compressors, condensers, coolers, etc. The cooling device is cooled to a predetermined temperature. In an open showcase with a large opening, a cold air curtain is formed in the opening to suppress the intrusion of outside air into the storage room, but during the daytime when many customers come to the store, customers and shop assistants etc. Since disturbance occurs, cold air is likely to leak, and outside air enters the storage chamber. This makes it difficult to maintain the temperature in the storage chamber at a predetermined cooling temperature. Therefore, in the cooling operation at the time of opening a store such as in the daytime, a cooling target temperature is set and maintained at a predetermined cooling temperature in consideration of a temperature increase due to disturbance.

  On the other hand, at night or when the store is closed, the disturbance due to the traffic of customers and the like is reduced, so that the leakage of cold air is reduced. Moreover, since the front opening part of an open showcase is obstruct | occluded with a night cover, the penetration | invasion of external air and the leakage of cold air are suppressed. Therefore, conventionally, as shown in Patent Document 1, when the store is closed, it is detected that the night cover is closed manually by turning off the lighting switch, and the cooling set temperature in the storage chamber is raised. In other words, so-called night setback control is performed.

Thereby, the operation control of the cooling device of the showcase is performed based on the energization control of the lighting device, thereby reducing the operation rate of the cooling device outside business hours and saving energy.
JP 2002-257451 A

  In the above case, the night setback control is started immediately after detecting that the night cover is closed by turning off the illumination switch regardless of the temperature in the storage chamber. Therefore, due to the influence of the disturbance, the temperature in the storage chamber is higher than the cooling set temperature, and the night setback control is started before the storage chamber is sufficiently cooled.

  Therefore, if the temperature in the storage chamber is higher than the cooling set temperature and the opening is blocked by the night cover, the thermal load in the storage chamber is suddenly reduced. The cooling target temperature after the increase (for example, the lower limit temperature that becomes the OFF point of the compressor) will be greatly below. Thereby, since the operation of the compressor is stopped until the temperature in the storage chamber rises to the corrected upper limit temperature (compressor OFF point temperature), the operation rate of the compressor is drastically reduced. .

  As a result, when the operating rate of the cooling device suddenly decreases, the temperature in the storage chamber will rise above the upper limit temperature (compressor ON point temperature) after correction for night setback control. As a result, the operating rate of the cooling device increases again.

  Therefore, at the beginning of the night setback control, the temperature in the storage chamber changes greatly and becomes unstable, and the operation rate of the cooling device also becomes unstable. As a result, effective energy-saving operation cannot be executed. There is.

  The present invention has been made to solve the conventional technical problem, and provides an open showcase that can stably perform an energy saving operation when an opening is closed by a night cover.

  The open showcase of the present invention cools the storage room while discharging cold air heat-exchanged with the cooler by an internal fan to the opening part of the storage room to form a cold air curtain, and a night cover that covers the opening part. An illumination device that illuminates the storage chamber, a temperature sensor that detects a temperature in the storage chamber, and a control device. The control device is a storage that the temperature sensor detects when the illumination device is turned off. On condition that the indoor temperature is stable, a predetermined energy-saving operation including at least a control for increasing the set temperature in the storage room is performed.

  The open showcase according to a second aspect of the present invention is characterized in that, in the above invention, the energy saving operation includes a control for reducing the rotational speed of the internal fan while monitoring the temperature in the storage chamber.

  In the open showcase of the invention of claim 3, in each of the above-described inventions, the energy saving operation is performed by monitoring the temperature in the storage chamber and rotating the cooling fan and the condenser constituting the predetermined refrigerant circuit for air cooling. It includes a control for lowering.

  In the open showcase of the invention of claim 4, in each of the above inventions, the energy saving operation includes a control for reducing the maximum rotational speed of the condensing fan for air-cooling the condenser and the condenser constituting the predetermined refrigerant circuit. It is characterized by.

  According to the present invention, the storage room is cooled while discharging the cold air heat-exchanged with the cooler by the internal fan to the opening part of the storage room to form the cold air curtain, and the night cover that covers the opening part is provided. The open showcase includes a lighting device that illuminates the storage chamber, a temperature sensor that detects the temperature in the storage chamber, and a control device. The control device detects the temperature in the storage chamber that is detected by the temperature sensor when the lighting device is turned off. On the condition that the temperature is stable, by executing a predetermined energy-saving operation including at least control for increasing the set temperature in the storage chamber, the set temperature in the storage chamber can be changed from a state in which the storage chamber is sufficiently cooled. By performing control to increase the power, stable energy saving operation can be performed.

  Accordingly, it is possible to execute appropriate temperature control that suppresses a rapid change in the internal temperature and reduces so-called overshoot and undershoot.

  According to the invention of claim 2, in the above invention, the energy saving operation includes a control for reducing the number of rotations of the internal fan while monitoring the temperature in the storage room, so the internal fan according to the temperature condition in the storage room The number of rotations can be reduced, and the amount of power consumption can be reduced.

  In this case, since the disturbance is reduced because the lighting device is turned off and the opening is closed by the night cover, the heat load in the storage chamber is reduced and the temperature rise is also reduced. Even if the number of rotations is decreased, it is possible to maintain the ability to cool the storage chamber without hindrance. In addition, the generation of noise can be suppressed, and the noise can be reduced.

  According to the invention of claim 3, in each of the above-mentioned inventions, the energy saving operation reduces the rotational speed of the condensing fan for cooling the condenser and the condenser constituting the predetermined refrigerant circuit while monitoring the temperature in the storage chamber. Therefore, it is possible to reduce the rotational speed of the condensing fan according to the temperature condition in the storage chamber, and to reduce the power consumption.

  In this case, since the disturbance is reduced because the lighting device is turned off and the opening is closed by the night cover, the heat load in the storage chamber is reduced and the temperature rise is also reduced. Even if the number of rotations is decreased, it is possible to maintain the ability to cool the storage chamber without hindrance. In addition, the generation of noise can be suppressed, and the noise can be reduced.

  According to the invention of claim 4, in each of the above-mentioned inventions, the energy saving operation includes control for reducing the maximum rotational speed of the condensing fan for air-cooling the condenser and the condenser constituting the predetermined refrigerant circuit. The amount of electric power can be reduced, and energy saving operation can be realized.

  In this case, since the disturbance is reduced because the lighting device is turned off and the opening is closed by the night cover, the thermal load in the storage chamber is reduced and the temperature rise is also reduced. Even if the maximum number of revolutions is reduced, it is possible to maintain the ability to cool the storage chamber without hindrance. Therefore, the generation of noise can be suppressed and the noise can be reduced.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a showcase 1 to which the present invention is applied, and FIG. 2 is a longitudinal side view of the showcase 1 of FIG.

  The showcase 1 is a vertical open showcase that is installed in a store such as a supermarket, for example, and is attached to the side surface of the heat insulating wall 2 at the installation site, and a heat insulating wall 2 having a substantially U-shaped cross section that opens to the front. It is comprised from the heat insulating side plates 5 and 5.

  An inner wall 4 is attached to the inside of the heat insulating wall 2 of the showcase 1 with a predetermined interval, and a partition wall 40 is attached between the inner wall 4 and the heat insulating wall 2 with an interval therebetween. An inner layer duct 41 is formed between 4 and the partition wall 40, and an outer layer duct 42 is formed between the partition wall 40 and the heat insulating wall 2. In front of the lower end of the back inner wall 10 constituting the inner wall 4, a bottom plate 9 is attached with a gap for a duct between the bottom wall 2 </ b> A of the heat insulating wall 2, and the inside of the inner wall 4 and the bottom plate 9 is disposed inside. A storage room 11 is provided.

  In addition, in the storage chamber 11, the height and the mounting angle can be changed, and a pair of brackets 31 attached to a column (not shown) on the back of the storage chamber 11 and a shelf plate 32 that constitutes a shelf device together with these brackets 31. It is constructed over several stages. A price rail 34 formed of hard synthetic resin is attached to the front edge of the shelf board 32, and the price rail 34 also serves as a decorative body for the shelf board 32. Further, a predetermined interval is formed between the front wall of the shelf board 32 and the price rail 34, and a guard 35 for preventing the products on the shelf board 32 from falling is provided at the interval. It is attached. In addition, an illuminating device (for example, a fluorescent lamp) 36 for illuminating commodities displayed on the lower shelf 32 is disposed in front of the lower surface of each shelf 32.

  An inner layer outlet 16 and an outer layer outlet 17 to which honeycomb materials 13 and 14 are respectively attached are arranged in parallel at the upper edge of the front opening (opening) 12 of the heat insulating wall 2. The outlet 17 communicates with the inner layer duct 41 and the outer layer duct 42, respectively. The inner layer outlet 16 and the outer layer outlet 17 are partitioned by a partition member 45 at the front end of the partition wall 40. On the other hand, an inner layer suction port 18 and an outer layer suction port 19 are arranged in parallel at the lower edge of the opening 12. An illuminating device (for example, a fluorescent lamp) 39 for illuminating the interior of the storage chamber 11 from above is provided on the top inner wall 8 of the inner layer outlet 16 on the storage chamber 11 side.

  In addition, a panel 33 is attached to the front end of the ceiling wall 2B of the heat insulating wall 2, and illumination for attaching an illumination device (for example, a fluorescent lamp) 37 located behind the panel 33 inside the panel 33. A reflector 50 is attached.

  In addition, an air outlet outer wall 52 that extends downward and is positioned on the front side of the outer layer air outlet 17 and closes the front end of the outer layer duct 42 is attached to the front end of the top wall 2B of the heat insulating wall 2. Note that the blower outlet outer wall 52 is formed with an engaging portion (not shown) whose lower end is folded back to the rear side, and the front end of the honeycomb material 14 attached to the outer layer blower outlet 17 is supported by the engaging portion. The And on the upper surface of this blower outlet outer wall 52, the roll-up type night cover 51 is accommodated in the front end of the top wall 2B of the heat insulation wall 2.

  The night cover 51 is wound around a torsion bar attached to a holder (not shown) and is urged in a direction in which the night cover 51 is always taken up. The night cover 51 can be drawn downward from the front end of the lower surface of the holder. When it is pulled out, it also has a stopper function that stops at a position halfway between full open and full close. This stopper function is released by a predetermined operation of pulling downward and is wound up. As a result, the night cover 51 can be drawn / wound freely on the holder.

  Further, the lateral width of the night cover 51 is substantially equal to the width dimension of the opening 12 in the embodiment. An edge member made of hard resin stretched to the left and right is attached to the front end (lower end) of the night cover 51, and a handle is formed at the center of the edge member. The fixing member formed on the edge member or the handle can be detachably attached to the locking member on the upper end of the front wall at the lower part of the heat insulating wall 2.

  On the other hand, a plurality of internal fans 27 and 28 (shown only in FIG. 4) corresponding to the inner layer duct 41 and the outer layer duct 42 are installed on the bottom wall 2A of the heat insulating wall 2 at the lower rear portion of the bottom plate 9. A cooler 46 (only FIG. 3 is shown) of the cooling device is vertically installed in the inner layer duct 41 behind the back inner wall 10. The compressor 26 (only shown in FIG. 3), the condenser 47, the condensing fan 43 (only shown in FIG. 3), etc. that constitute the refrigeration cycle together with the cooler 46 are provided separately from the showcase 1, for example, in a store Is installed in the machine room.

  Here, the refrigerant circuit 25 constituting the refrigeration cycle in the present embodiment will be described with reference to the refrigerant circuit diagram of FIG. A condenser 47 is connected to the piping 48 on the discharge side of the compressor 26. An expansion valve 29 as a pressure reducing device is connected to the outlet side of the capacitor 47. The expansion valve 29 is connected to a cooler 46, and the outlet side of the cooler 46 is connected to the compressor 26 to constitute an annular refrigeration cycle. The compressor 26, the internal fans 27 and 28, the condensing fan 43, and the expansion valve 29 are connected to the control device 20 described later, and the cooling operation is controlled as will be described in detail later.

  Next, the control device 20 will be described in detail with reference to FIG. FIG. 4 shows a block diagram of the control device 20 of the showcase 1. The control device 20 is constituted by a general-purpose microcomputer and includes a timer 21 as a time limit means. And the input of this control apparatus 20 performs lighting / extinguishing of the temperature sensor 22 which detects the temperature in the storage chamber 11, the power switch 23, and the illuminating devices 36, 37 and 39 which illuminate the interior of the storage chamber 11. A lighting switch 24 and the like are connected. In addition, the temperature sensor 22 is attached to the ceiling part in the storage chamber 11, for example.

  On the other hand, the output of the control device 20 includes a compressor motor 26M that drives the compressor 26, fan motors 27M and 28M that drive the internal fans 27 and 28, a fan motor 43M that drives the condensing fan 43, and electromagnetic A valve 29 and lighting devices 36, 37, 39 are connected. Here, the compressor motor 26M is connected via the inverter device 53, whereby the operating frequency of the compressor motor 26M can be arbitrarily changed. The fan motors 27M and 28M of the internal fans 27 and 28 are connected to each other via a drive circuit 54 such as a chopper circuit, so that the rotational speeds of the fan motors 27M and 28M can be arbitrarily changed. ing. Similarly, the fan motor 43M of the condensing fan 43 is connected via a drive circuit 55 such as a chopper circuit, whereby the rotational speed of the fan motor 43M can be arbitrarily changed.

  The operation of the showcase 1 of the embodiment of the present invention with the above configuration will be described. First, when the power switch 23 is turned on, the control device 20 starts a cooling operation and activates the compressor 26 and the internal fans 27 and 28. When the compressor 26 is started, the cooler 46 provided vertically in the inner layer duct 41 exhibits a cooling action. The cold air that has exchanged heat with the cooler 46 is raised in the inner layer duct 41 by the operation of the internal fan 27 and blown out from the inner layer outlet 16 toward the inner layer inlet 18. The cold air sucked from the inner layer suction port 18 is accelerated again by the internal fan 27. Thereby, a cold air curtain is formed in the opening 12.

  On the other hand, when the internal fan 28 corresponding to the outer layer duct 42 is operated, the protective airflow in the outer layer duct 42 is raised in the outer layer duct 42 and blown out from the outer layer air outlet 17 toward the outer layer air inlet 19. Then, the air sucked from the outer layer suction port 19 is accelerated again by the internal fan 28. As a result, a protective air curtain is formed outside the cold air curtain in the opening 12, and a front and rear double air curtain is formed in the opening 12. Then, a part of the inner cool air curtain is circulated in the storage chamber 11 to cool the storage chamber 11.

  The control device 20 continuously operates the internal fans 27 and 28, and the rotation speed of the compressor 26 and the condensing fan 43 is controlled by the inverter device 53 or the drive circuit 55 based on the output of the temperature sensor 22. That is, when the temperature in the storage chamber 11 detected by the temperature sensor 22 is equal to or higher than a predetermined upper limit temperature (for example, + 6 ° C.) set above a predetermined cooling set temperature (for example, + 5 ° C.), the compressor 26 and the condensing fan 43 are operated at the maximum rotational speed. When the detected temperature is lower than the upper limit temperature and higher than a predetermined lower limit temperature (for example, + 4 ° C.) set below the set temperature, the compressor 26 and the condensing fan 43 rotate as the temperature increases. The number is increased, and the rotational speed of the compressor 26 and the condensing fan 43 is decreased as the temperature decreases. That is, the rotational speeds of the compressor 26 and the condensing fan 43 are adjusted according to changes in the temperature detected by the temperature sensor 22. Further, when the detected temperature is equal to or lower than the lower limit temperature, the operation of the compressor 26 and the condensing fan 43 is stopped. In this case, when the temperature in the storage chamber 11 detected by the temperature sensor 22 rises above the predetermined upper limit temperature, the compressor 26 and the condensing fan 43 are activated and operated at the maximum rotational speed.

  In the above-described embodiment, the control is performed in the range of the differential 2 deg of the cooling set temperature, but is not limited to this. Further, since the compressor 26 is controlled by the inverter device 53 and the condensing fan 43 is controlled by the drive device 55, the rotational speed can be controlled. You may perform ON / OFF control by temperature and minimum temperature.

  As a result, the inside of the storage chamber 11 is cooled to a refrigeration temperature of average + 5 ° C. In this embodiment, the temperature control in the storage chamber 11 is performed only by the operation control of the compressor 26 and the condensing fan 43, but the present invention is not limited to this, and in addition to this, the electromagnetic valve 29 The temperature control may be performed by performing the opening degree control by.

  Next, the cooling operation when the opening 12 is closed by the night cover 51 as described above will be described with reference to the control flowchart of FIG. First, the control device 20 determines whether or not the illumination switch 24 is turned off in step S1. For example, when the store is open, the lighting switch 24 is turned on and the night cover 51 is wound around the holder. Therefore, in the open state where the opening 12 is open, the control device 20 proceeds to step S2 and, as described above, based on the temperature in the storage chamber 11 detected by the temperature sensor 22, the compressor 26. And the rotation speed control (ON / OFF control) of the condensing fan 43 is performed, and the inside of the storage chamber 11 is maintained at a predetermined cooling set temperature. Thereafter, the process returns to step S1.

  When closing the store, the night cover 51 is pulled out from the holder and lowered, and a handle or the like is locked to a locking member formed on the upper end of the front wall of the heat insulating wall 2 to cover the opening 12 outside the cold air curtain. . Thereby, during the closing of the store, the opening 12 is closed with the night cover 51, whereby the cool air in the storage chamber 11 can be retained in the storage chamber 11, and the cooling efficiency is improved.

  At this time, when the store is closed, the lighting switch 24 is turned off, and the lighting devices 36, 37, and 39 are turned off. Therefore, since the lighting switch 24 is turned off, the control device 20 proceeds to step S3 in step S1. In step S <b> 3, the control device 20 determines the temperature stability in the storage chamber 11.

  In the stability determination of the temperature in the storage chamber 11, the determination is made based on whether or not a predetermined time has elapsed for a stable time during which the temperature change detected by the temperature sensor 22 is within a predetermined value. In this embodiment, the time required for determination is, for example, 10 minutes. Therefore, in step S3, it is determined whether or not 10 minutes (predetermined time) has elapsed since the temperature change detected by the temperature sensor 22 is within a predetermined value of 1 to 3 degrees, for example, within 2 degrees.

  If the stable time has not passed the predetermined time, even if the night cover 51 is actually closed, the control device 20 still considers that the night cover 51 is not closed, and the above step S2 The normal cooling operation as described above is continued.

  On the other hand, when the stable time has passed the predetermined time, the control device 20 considers that the opening 12 is closed by the night cover 51 and the temperature change in the storage chamber 11 is stable, and proceeds to step S4. Perform the specified energy-saving operation.

  That is, when the opening 12 is closed by the night cover 51, if the temperature in the storage chamber 11 is still higher than the cooling set temperature due to the influence of disturbance or the like, the night cover 51 closes the opening 12. As a result, the heat load in the storage chamber 11 is drastically reduced, and therefore, when there is a significant temperature change in the storage chamber 11, the energy saving operation is not performed.

  Then, when shifting to the energy saving operation, the control device 20 performs a correction for increasing the cooling set temperature during the normal cooling operation as described above by a predetermined temperature (for example, 2 to 3 deg), and the corrected cooling set temperature is used. Execute the cooling operation. That is, the upper limit temperature (for example, + 9 ° C.) and the lower limit temperature (for example, + 7 ° C.) are similarly corrected according to the corrected cooling set temperature (for example, + 8 ° C.), and the compressor 26 and the condensing are corrected using the temperatures. The rotational speed of the fan 43 is controlled. Specifically, when the temperature in the storage chamber 11 detected by the temperature sensor 22 is equal to or higher than the corrected upper limit temperature, the compressor 26 and the condensing fan 43 are operated at the maximum rotational speed. When the detected temperature is lower than the upper limit temperature and higher than the corrected lower limit temperature, the rotational speeds of the compressor 26 and the condensing fan 43 are increased as the temperature increases, and the compressor is increased as the temperature decreases. 26 and the condensing fan 43 are stopped when the detected temperature at which the rotational speed of the condensing fan 43 is lower than the lower limit temperature. Also in this case, when the temperature in the storage chamber 11 detected by the temperature sensor 22 rises above the corrected upper limit temperature, the compressor 26 and the condensing fan 43 are started and operated at the maximum rotational speed.

  For this reason, the operation of the cooling device is controlled at the normal cooling set temperature while the opening 12 of the storage chamber 11 is closed by the night cover 51, so that the temperature in the storage chamber 11 is suddenly reduced to a predetermined lower limit. Even if an undershoot that falls below the temperature (lower limit temperature before correction) occurs, the cooling is controlled by the normal cooling set temperature (cooling set temperature before correction), so the undershoot (before correction) The difference between the lower limit temperature and the actual temperature in the storage chamber 11) can be reduced. And since the cooling device is operated when the temperature in the storage chamber 11 reaches the upper limit temperature before correction, the overshoot that exceeds the upper limit temperature before correction can be significantly reduced. Thereby, after closing the opening part 12 with the night cover 51, it becomes possible to set it as the stable state by which sufficient cooling in the storage chamber 11 was performed at an early stage.

  By executing the energy-saving operation that raises the cooling set temperature in a state where the temperature in the storage chamber 11 is stable, it becomes possible to execute a stable energy-saving operation, suppressing a sudden change in the internal temperature, Appropriate temperature control can be performed with so-called overshoot and undershoot reduced.

  In this case, the control device 20 operates by reducing the maximum rotational speed of the condensing fan 43 below the currently set maximum rotational speed in the energy saving operation. In this embodiment, the maximum rotational speed currently set by the drive circuit 55 is reduced by 1 step, and the rotational speed control is executed by the corrected upper limit temperature and lower limit temperature as described above.

  Thereby, since energy-saving operation also performs control which lowers the maximum number of rotations of condensing fan 43, it can aim at reduction of the amount of power consumption, and it becomes possible to realize energy-saving operation.

  In this case, since the disturbance is reduced by the illumination device 43 being turned off and the opening 12 being closed by the night cover 51, the heat load in the storage chamber 11 is reduced and the temperature rise is also reduced. Even if the maximum number of rotations of the condensing fan 43 is lowered, it is possible to maintain the ability to cool the interior of the storage chamber 11 without any trouble. Therefore, the generation of noise can be suppressed and the noise can be reduced.

  Thereafter, the control device 20 returns from step S4 to step S1. After the lighting switch 24 is turned OFF and the stable time has passed in which the temperature change in the storage chamber 11 detected by the temperature sensor 22 is within a predetermined value as described above in step S3. When the process proceeds to step S4 again, the maximum rotational speed of the condensing fan 43 currently set by the drive circuit 55 is further reduced by one step, and the rotational speed control is executed based on the corrected upper limit temperature and lower limit temperature. . When the maximum rotational speed of the condensing fan 43 reaches a preset minimum value, the rotational speed control of the condensing fan 43 is performed as the maximum rotational speed of the minimum value.

  Therefore, since the energy saving operation also executes control for reducing the rotational speed of the condensing fan 43 while monitoring the temperature in the storage chamber 11, the rotational speed of the condensing fan 43 according to the temperature condition in the storage chamber 11. The power consumption can be reduced, and the power consumption can be reduced.

  Also in this case, since the illuminating devices 36, 37, and 39 are turned off and the opening 12 is blocked by the night cover 51, the disturbance is reduced, so that the heat load in the storage chamber 11 is reduced. Since the temperature rise is also reduced, it is possible to maintain the ability to cool the interior of the storage chamber 11 without hindrance even if the rotational speed of the condensing fan 43 is reduced. In addition, the generation of noise can be suppressed, and the noise can be reduced.

  Furthermore, in the energy saving operation, in addition to the rotational speed control of the compressor 26 and the condensing fan 43, the rotational speeds of the internal fans 27 and 28 may be controlled using the corrected cooling set temperature. When the temperature in the storage chamber 11 detected by the temperature sensor 22 is equal to or higher than the corrected upper limit temperature, the drive circuit 54 operates the rotation speed of the internal fans 27 and 28 as the maximum rotation speed. When the detected temperature is lower than the upper limit temperature and higher than the corrected lower limit temperature, the number of rotations of the internal fans 27 and 28 is increased as the temperature increases, and the internal fan 27 is increased as the temperature decreases. , 28 is reduced. If the detected temperature is equal to or lower than the lower limit temperature, the operation of the internal fans 27 and 28 is stopped. Also in this case, when the temperature in the storage chamber 11 detected by the temperature sensor 22 rises above the corrected upper limit temperature, the internal fans 27 and 28 are activated and operated at the maximum rotational speed.

  Further, the control device 20 operates by reducing the maximum rotational speed of the internal fans 27 and 28 below the currently set maximum rotational speed in the energy saving operation. In this embodiment, the maximum rotational speed currently set by the drive circuit 54 is reduced by 1 step, and the rotational speed control is executed by the corrected upper limit temperature and lower limit temperature as described above.

  Thereafter, the control device 20 returns from step S4 to step S1. The illumination switch 24 is turned off, and after a stable time has elapsed in which the change in the temperature in the storage chamber 11 detected by the temperature sensor 22 is within a predetermined value as described above in step S3, again. When the process proceeds to step S4, the maximum rotational speed of the internal fans 27 and 28 currently set by the drive circuit 54 is further reduced by one step, and the rotational speed control is executed based on the corrected upper limit temperature and lower limit temperature. . When the maximum rotational speed of the internal fans 27 and 28 reaches a preset minimum value, the rotational speed control of the internal fans 27 and 28 is performed as the maximum rotational speed of the minimum value.

  Thereby, even when the energy-saving operation is being executed, the number of rotations of the internal fans 27 and 28 can be reduced according to the temperature state in the storage chamber 11, and the power consumption can be reduced. it can.

  In this case, since the disturbance is reduced because the lighting devices 36, 37, 39 are turned off and the opening 12 is closed by the night cover 51, the heat load in the storage chamber 11 is reduced and the temperature is reduced. Since the rise is also reduced, it is possible to maintain the ability to cool the interior of the storage chamber 11 without hindrance even if the rotational speed of the internal fans 27 and 28 is reduced. In addition, the generation of noise can be suppressed, and the noise can be reduced.

  When the energy saving operation is being performed, if the illumination switch 24 is turned on in step S1, or the stability change in step S3, the temperature change detected by the temperature sensor 22 is within a predetermined value. If the set stable time deviates from the predetermined value range without the predetermined time, it is considered that the temperature in the storage chamber 11 has become unstable, that is, the night cover 51 has been opened. In step S2, the normal cooling operation is performed.

  In this case, the control device 20 performs normal cooling when the temperature in the storage chamber 11 is considered to be unstable in step S3 on the condition that the lighting switch 24 is turned off. Instead of the operation, the maximum rotation speed of the condensing fan 43 in the energy saving operation and the maximum rotation speed of the internal fans 27 and 28 may be increased by 1 step, and the control may be returned to step S1 again.

  Thereby, in the energy-saving operation, the cooling device is maintained at a low operation rate by monitoring the temperature change state in the storage chamber 11 and controlling the rotational speed of the condensing fan 43 and the internal fans 27 and 28. Meanwhile, the temperature in the storage chamber 11 can be maintained at a predetermined cooling temperature. Therefore, stable energy saving operation can be realized.

  As shown in the flowchart of FIG. 6, step S5 is provided between step S3 and step S4, and the control device 20 allows the operation rate of the compressor 26 to be a predetermined low operation rate (in this embodiment, , 20%), and the energy saving operation similar to the above may be executed only when it is lower than the low operation rate.

  Accordingly, it is possible to shift from the normal cooling operation to the energy saving operation when the opening 12 is closed by the night cover 51 in consideration of the operation rate of the compressor 26, and the inside of the storage chamber 11 is sufficiently cooled. By performing control to increase the set temperature in the storage chamber 11 from the inserted state, it is possible to execute a stable energy saving operation with high accuracy.

It is a perspective view of a showcase. It is a vertical side view of the showcase of FIG. It is a refrigerant circuit diagram. It is an electrical block diagram of a control apparatus. It is a flowchart of control. It is a flowchart of control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Open showcase 2 Heat insulation wall 9 Bottom plate 10 Back inner wall 11 Storage room 12 Front opening (opening part)
16 Inner layer outlet 17 Outer layer outlet 20 Control device 21 Timer 22 Temperature sensor 23 Power switch 24 Illumination switch 25 Refrigerant circuit 26 Compressor 36, 37, 39 Illumination device 40 Partition wall 41 Inner layer duct 42 Outer layer duct 43 Condensing fan 46 Cooling 47 Capacitor 48 Refrigerant piping 51 Night cover 53 Inverter device 54 Drive circuit 55 Drive circuit

Claims (4)

In an open showcase provided with a night cover that covers the opening while cooling the storage chamber while discharging a cool air exchanged with a cooler by an internal fan to the opening of the storage chamber to form a cool air curtain ,
A lighting device that illuminates the storage room, a temperature sensor that detects the temperature of the storage room, and a control device;
The control device includes a control for increasing at least a set temperature in the storage chamber on condition that the temperature in the storage chamber detected by the temperature sensor is stable when the lighting device is turned off. An open showcase featuring energy-saving operation.   2. The open showcase according to claim 1, wherein the energy-saving operation includes a control for reducing a rotation speed of the internal fan while monitoring a temperature in the storage room.   The energy-saving operation includes a control for reducing the number of revolutions of a condensing fan for cooling the condenser and a condenser constituting a predetermined refrigerant circuit while monitoring the temperature in the storage chamber. The open showcase according to claim 1 or claim 2.   4. The energy-saving operation includes a control for reducing a maximum rotational speed of a condensing fan for air-cooling a condenser that constitutes a predetermined refrigerant circuit with the cooler. Open showcase described in.

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