JP3271699B2 - Open showcase driving method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating an open showcase in which a plurality of coolers are installed and defrosting operations are alternately performed to suppress fluctuations in the internal temperature during defrosting operations.

[0002]

2. Description of the Related Art Conventionally, a plurality of coolers have been installed and defrosting operations have been performed alternately to suppress fluctuations in the temperature (in-compartment temperature) in a storage room during defrosting operation. Differential cases are often used. However, in this conventional non-defective case, the size and the operation time of a pair of coolers that perform defrosting alternately are the same, and the interval of the defrosting operation (interval) does not take into account the business hours of the store. Did not.

[0003] In some cases, the size and operation time of both coolers are changed by using a main cooler (in an inner duct) and an auxiliary cooler (in an outer duct). The structure becomes complicated, and in this case as well, the business hours of the store are not taken into account as described above.

[0004]

On the other hand, in a large store,
It is premised that the product will be sold out on the same day, but recently, chilled meat, sashimi, fillet, crust etc. in semi-frozen state may be displayed, even if the temperature rises slightly during defrosting operation,
These semi-frozen products cause great damage and are a big problem in freshness-oriented stores.

The present invention has been made in view of the above circumstances, and an object of the present invention is to switch a main cooler and an auxiliary cooler between a cooling operation and a defrosting operation at a predetermined timing to perform defrosting. It is an object of the present invention to provide a method of operating an open showcase that can suppress a rise in the internal temperature during operation and can display a semi-frozen product without any problem.

[0006]

In order to solve the above-mentioned problems, according to the present invention, a storage chamber having a front opening is formed in a main body constituted by a heat insulating wall, and an opening of the storage chamber is stored in the storage chamber. In an open showcase that cools a storage room by covering it with an air curtain of cold air blown downward from an air outlet provided at an upper front end of the room, a main cooler is provided in a duct defined by the storage room. And an auxiliary cooler that performs a cooling operation during the defrosting operation of the main cooler is provided on the leeward side of the main cooler, and the main cooler and the auxiliary cooler are alternately operated. Features.

As described above, when the main cooler is performing the defrosting operation, the cooling operation is performed by the auxiliary cooler provided on the leeward side, and when the main cooler is performing the normal cooling operation, the auxiliary cooling is performed. By stopping the cooling operation of the coolers and alternately operating both coolers, it is possible to reliably prevent the temperature of the cool air blown into the storage room from rising.

Further, in the operating method of the open showcase of the present invention, the defrosting operation of the main cooler is performed in an off-cycle system, and the latent heat of melting of ice frosted on the main cooler is cooled by the auxiliary cooler. Use in addition to driving. By performing the defrosting of the main cooler in the off cycle as described above, the temperature of the cool air blown out from the main cooler during the defrosting operation becomes approximately 0 ° C., so that the load on the auxiliary cooler can be reduced and the amount of frost formation can be reduced. Can be reduced.

Further, by setting the total cooling operation time of the main cooler to be longer than the total cooling operation time of the auxiliary cooler, the auxiliary cooler is removed by low-temperature cold air blown from the main cooler during the cooling operation. Defrosting can be performed, and the defrosting operation of the auxiliary cooler can be performed in an off-cycle manner, so that the temperature of the cool air blown out through the auxiliary cooler does not excessively increase.

[0010] Further, after the defrosting operation of the main cooler is completed, the cooling operation of the auxiliary cooler is continued for a predetermined time, thereby increasing the temperature until the cooling temperature of the cool air by the main cooler reaches the predetermined temperature. Can be prevented. In addition, the interval of the defrosting operation is set differently during business hours and during non-business hours at the place where the open showcase is installed, and the defrosting operation of the main cooler during non-business hours when the load decreases is extended. By doing so, defrosting of the main cooler can be performed more reliably.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 is a sectional side view of an open showcase provided with a main cooler and an auxiliary cooler.

The open showcase 1 has a heat insulating wall 2
A multi-stage storage room 4 having an open front is formed in a main body 3 composed of a main body 3 and an outer-layer duct 5 and an inner-layer duct 6 are provided on the back of the main body 3, and a main cooler 7 and an auxiliary are provided in the inner-layer duct 6. A cooler 8 is provided. The outer-layer duct 5 and the inner-layer duct 6 are provided with an outer-layer fan 9 and an inner-layer fan 10 for circulating cool air in each duct, respectively. An auxiliary heater 11 is provided immediately before the main cooler 7, and an anti-icing heater 12 is provided above the main cooler 7.

At the upper front end position of the main body 3, a cold air outlet 13 having a honeycomb structure is provided over the entire longitudinal direction of the case, from which the cool air from each of the inner and outer ducts is rectified and blown downward as an air curtain. The front opening of the case is covered and the inside of the storage room 4 is cooled.
In addition, a suction port 14 communicating with each of the inner and outer ducts is provided in a lower front portion of the main body 3, and cool air sucked by the outer layer fan 9 and the inner layer fan 10 from the suction port 14 is supplied to the outer layer duct 5 and the inner layer duct. 6 respectively. Further, a perforated plate is used for the rear panel 15 of the storage room 4, and the cool air cooled by the two coolers 7 and 8 is formed so as to blow out from the inner layer duct 6 directly into the storage room 4.

The cold air flowing through the outer layer duct 5 acts as a heat insulating layer, and then blows out from the outlet 13 to be drawn into the inlet 1.
Cycle to 4. The cool air that has flowed into the inner duct 6 is cooled by the main cooler 7 or the auxiliary cooler 8 to a predetermined temperature, and is blown out from the outlet 13 and circulated as described above.

Next, each operation state will be described with reference to FIGS. 2 to 4 are explanatory diagrams showing a piping system of the main cooler 7 and the auxiliary cooler 8 in the refrigeration cycle, in which the white valves are open and the black valves are closed. It indicates that there is. The hatched coolers indicate the cooling operation, and the white coolers indicate the off-cycle method during the defrosting operation.

First, the high-pressure pipes 21 of the main cooler 7 and the auxiliary cooler 8 are branched on the upstream side of the liquid solenoid valves 22, 23, and are connected via expansion valves 24, 25 of a predetermined capacity, respectively. I have. Also, the suction pipes 26, 2 of the cooling units 7, 8 are provided.
7 is connected to a compressor (not shown) after merging.

First, FIG. 2 shows a state in which the main cooler 7 is in operation. The liquid solenoid valve 22 of the main cooler 7 is open, the liquid solenoid valve 23 of the auxiliary cooler 8 is closed, The auxiliary cooler 8 is
An off-cycle defrosting state in which no refrigerant is supplied is being performed. In this state, the cool air that has flowed into the inner duct 6 is cooled to a predetermined temperature by the main cooler 7 during operation, and then passes through the auxiliary cooler 8 so as to pass through the outlet 13 and the rear panel 15.
And the inside of the storage room 4 is maintained at a predetermined temperature.

On the other hand, in the auxiliary cooler 8, the off-cycle defrosting of the frosted coil surface in the previous cooling operation is performed by passing the cool air blown out from the main cooler 7. Since this off-cycle defrosting is performed by passing cool air,
Although the efficiency of defrosting is not good, as will be described later, the operation time of the auxiliary cooler 8 itself is short, and since the temperature of the intake cold air at this time is low, the amount of frost is not so large. The off-cycle defrost of the auxiliary cooler 8 can be completely performed.

The above operation state is performed, for example, for 4 to 5 hours in order to completely perform the off-cycle defrosting of the auxiliary cooler 8. In order to prevent water droplets generated by the defrosting operation of the auxiliary cooler 8 from dropping on the upper part of the main cooler 7 and growing as ice, the anti-icing heater 12 is energized as necessary. The anti-icing heater 12 can obtain a sufficient effect with a heater having a small capacity. The heater having a very small capacity may be always energized, or a heater having a slightly larger capacity may be used at predetermined intervals. You may make it electrically energize.

Here, when the interior of the storage room of the open showcase is kept at 0-1 ° C. suitable for storing fresh products, it is necessary to blow cool air of about −5 ° C. from the outlet 13; The temperature of the cold air sucked from the mouth 14 is usually 2.0 to 3.0 ° C. Therefore, the cold air temperature at the inlet of the main cooler 7 shown in the figure is 2.0 to 3.0.
° C. In the main cooler 7, it is cooled and the average temperature of the cold air at the outlet of the main cooler 7 (the inlet of the auxiliary cooler 8) shown in the figure is -4.5 to -5. 5 ° C. (the refrigerant evaporation temperature in the cooler is −10 to −13 ° C.). This control can be performed by opening and closing the liquid solenoid valve 22 using a normal thermostat. Then, the cold air temperature at the outlet of the auxiliary cooler 8 shown in the figure temporarily decreases slightly due to the influence of the previous cooling operation, but gradually approaches the same temperature. Thereby, the inside of the storage room 4 is 0 to -1 ° C.
Can be kept.

Then, when the main cooler 7 enters the defrosting operation,
As shown in FIG. 3, the liquid electromagnetic valve 22 of the main cooler 7 is closed, the liquid electromagnetic valve 23 of the auxiliary cooler 8 is opened, the auxiliary cooler 8 performs a cooling operation, and the main cooler 7 is turned off. Do the frost. In this state, the main cooler 7 shown in FIG.
Since the cool air temperature at the inlet of the main cooler 7 is 2.0 to 3.0 ° C. on the positive side, even if the amount of frost on the main cooler 7 is large,
Defrosting can be completed in about 30 to 45 minutes.

At this time, the temperature of the cool air at the outlet of the main cooler 7 shown in the figure is about 0 to 0.5 ° C. as a result of the cool air being cooled by the latent heat of melting of the ice frosted on the main cooler 7. Become.
Therefore, the auxiliary cooler 8 may cool the cold air of 0 to 0.5 ° C to about -4.5 to -5.5 ° C as described above,
By using the latent heat of melting of the ice of the main cooler 7 in addition to the cooling operation of the auxiliary cooler 8, the size and capacity of the auxiliary cooler 8 can be reduced. The operation of the auxiliary cooler 8 at this time is, for example, by controlling the opening and closing of the liquid solenoid valve 23 by a thermostat, between -1.0 to -9.5 ° C, and an average temperature of -4.5 to -5.5 ° C. What should be done is. By making the total cooling operation time of the auxiliary cooler 8 shorter than the total cooling operation time of the main cooler, the amount of frost formed on the auxiliary cooler 8 can be made extremely small. Defrosting can be performed completely.

When the main cooler 7 completes the off-cycle defrosting, the operation state is changed to the operation state shown in FIG. 4, and the liquid solenoid valve 22 of the main cooler 7 is kept open while the liquid solenoid valve 23 of the auxiliary cooler 8 is opened.
Is opened, and the two coolers 7 and 8 perform a cooling operation at the same time. This state is performed, for example, for about 3 to 5 minutes until the main cooler 7 starts the predetermined cooling operation after the completion of the defrosting. At this time, the temperature of each part is determined by the main cooler 7 shown in FIG.
The inlet of the main cooler 7 has a temperature of 2.0 to 3.0 ° C. as described above, but the outlet of the main cooler 7 shown in FIG. Since the heat exchange efficiency is slightly lowered due to the influence of the frost remaining in the vessel 7, the temperature becomes -3.5 to -4.5 ° C at the start of the cooling operation immediately after the defrost, which is slightly higher. Therefore, by simultaneously performing the cooling operation of the auxiliary cooler 8 in this state, the cool air temperature at the outlet of the auxiliary cooler 8 shown in the figure can be set to a predetermined value of −4.5 to −5.5 ° C. it can.

When the cooling operation of the main cooler 7 is completed and the cool air can be sufficiently cooled only by the main cooler 7, the liquid solenoid valve 23 of the auxiliary cooler 8 is closed and FIG. Return to the normal operating state shown.

FIG. 5 shows an example of a time chart of the alternate operation of the main cooler 7 and the auxiliary cooler 8, and is a time chart when the business hours are from 10:00 to 20:00. In the figure, hatched portions indicate a state in which a cooling operation is being performed, and other portions indicate a state in which an off-cycle defrost is being performed.

First, for three hours from 0 o'clock to 3 o'clock in the night when the load is reduced due to the night cover being attached, the main cooler 7 performs off-cycle defrost longer than usual, and the main cooler 7 is defrosted. Do enough. At this time, the cooling operation is performed by the auxiliary cooler 8 having a low cooling capacity. However, since the load is reduced, the internal temperature does not increase.

During the next 5 hours from 3 o'clock to 8 o'clock, the cooling operation by the ordinary main cooler 7 is performed. At this time, FIG.
The cooling operation of the main cooler 7 after the defrosting shown in (1) can be omitted because the load is small.

During the 30 minutes from 8:00, in the middle and winter seasons, the cooling operation of the auxiliary cooler 8 is performed and the off-cycle defrosting of the main cooler 7 is performed as shown by the broken line X in the figure. On the other hand, in summer, this time period is a time period for repacking products in ordinary stores, and since the number of products displayed in the warehouse is extremely small compared to other time periods, both coolers are completely Perform a defrosting operation. That is, the supply of the refrigerant to both coolers is stopped to perform off-cycle defrost, or the auxiliary heater 11 is energized as necessary to perform complete defrost once a day.

For 4 hours and 30 minutes from 8:30 to 13:00, a normal cooling operation by the main cooler 7 which has completed the defrosting is performed, and for 45 minutes from 13:00 to 13:45, the above-mentioned FIG. , The off-cycle defrosting of the main cooler 7 and the cooling operation of the auxiliary cooler 8 are performed. Next, after the cooling operation of the main cooler 7 shown in FIG. 4 is performed from 13:45 to 3 to 5 minutes, a normal cooling operation by the main cooler 7 is performed until 18:15.

Further, the same off-cycle defrosting of the main cooler 7 as described above is performed for 45 minutes from 8:15, and after the cooling operation is performed for 3 to 5 minutes, the main cooler 7 is maintained for 5 hours until 24:00. The cooling operation by the cooler 7 is performed.

As described above, by changing the interval of the defrosting operation (distribution of the cooling operation and the defrosting operation) between the non-business hours during the non-business hours when the load decreases and the business hours, the temperature in the refrigerator is affected. Sufficient defrosting can be performed without giving, and a continuous cooling operation can be performed unless a large amount of frost is formed. Thereby, the display of the semi-frozen product can be performed without any problem.

FIG. 6 is a diagram showing a temperature change before and after the defrosting operation of the main cooler 7. The cold air temperature at the outlet of the main cooler 7 (portion in FIG. 2 and the like) gradually increases when the main cooler 7 enters off-cycle defrosting at point A. Since the cool air is cooled by the latent heat of melting, the temperature does not rise extremely but rises only to about 0.5 ° C. at the end of the defrosting operation at the point B. In this state, the auxiliary cooler 8 performs the cooling operation in the range of −1.0 to −9.5 ° C., so that the cool air temperature at the outlet of the auxiliary cooler 8 (portion in FIG. That is, the temperature of the air curtain blown out from the blowout port 12 is set to a predetermined value of -4.
The temperature can be 5 to -5.5 ° C.

After the defrosting of the main cooler 7, the two coolers simultaneously perform the cooling operation to perform the cooling operation of the main cooler 7 for 3 to 5 minutes, and the main cooler 7 performs the predetermined cooling operation. At the point of restart (point C), the cooling operation of the auxiliary cooler 8 is stopped, and the mode is switched to off-cycle defrosting. As described above, by simultaneously performing the cooling operation of both the coolers for only several minutes, it is possible to reliably prevent the temperature in the refrigerator from increasing.

[0034]

As described above, according to the present invention, the temperature inside the refrigerator does not increase even during the defrosting operation of the main cooler 7, so that the freshness of the semi-frozen product can be maintained without fail. High freshness management of the product can be performed. Furthermore, since the main cooler and the auxiliary cooler are installed in one duct,
Not only is the assembly structure easy, but it can be easily handled by adding an auxiliary cooler to a single standard cooler. Even if cold air is introduced into the refrigerator from the rear panel, no warm air is generated during the defrosting operation of the main cooler, so that no warm air flows into the refrigerator from the rear panel, and Since the inlet temperature during the cooling operation of the cooler is low, the amount of frost formed on the auxiliary cooler can be extremely reduced.

In addition, defrosting using the auxiliary heater can be performed once a day even in summer, especially when the amount of frost is large, so that energy can be saved. In addition, liquid defrosting and hot gas are not used for defrosting operation. It is simple and has a small number of solenoid valves, so that manufacturing costs and operating costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional side view of an open showcase showing a preferred embodiment of the present invention.

FIG. 2 is a diagram illustrating a piping system of a main cooler and an auxiliary cooler in a refrigeration cycle, and is an explanatory diagram illustrating a state where the main cooler is performing a cooling operation.

FIG. 3 is an explanatory diagram showing a state in which a main cooler is performing off-cycle defrosting and an auxiliary cooler is performing cooling operation.

FIG. 4 is an explanatory diagram showing a state in which both coolers are simultaneously performing a cooling operation.

FIG. 5 is a time chart showing an example of alternate operation of a main cooler and an auxiliary cooler.

FIG. 6 is a diagram showing a temperature change before and after a defrosting operation of a main cooler.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Open showcase 2 Insulated wall 3 Main body 4 Storage room 5 Outer duct 6 Inner duct 7 Main cooler 8 Auxiliary cooler 9 Outer fan 10 Inner fan 11 Auxiliary heater 12 Anti-icing heater 13 Outlet 14 Suction port 15 Back panel 21 High pressure Piping 22 Liquid electromagnetic valve of main cooler 7 23 Liquid electromagnetic valve of auxiliary cooler 8 24 Expansion valve of main cooler 7 Expansion valve of auxiliary cooler 8 26 Intake pipe of main cooler 7 27 Intake of auxiliary cooler 8 Piping

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-291084 (JP, A) JP-A-62-294879 (JP, A) JP-A-9-126603 (JP, A) JP-A-1- 137182 (JP, A) JP-A-5-87430 (JP, A) JP-A-4-57185 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25D 21/06 F25D 11 / 00 101

Claims (4)

(57) [Claims] 1. A storage room having an open front surface is formed in a main body constituted by a heat insulating wall, and an opening of the storage room is blown downward from an outlet provided at an upper front end of the storage room. In an open showcase that cools the storage room by covering it with an air curtain of cool air, a main cooler is provided in an inner layer duct defined by the storage room, and defrosting of the main cooler is located on the leeward side of the main cooler. An auxiliary cooler that performs a cooling operation during operation is provided, and the main cooler and the auxiliary cooler are alternately operated, and the defrosting operation of the main cooler is performed in an off cycle method, and the main cooler is The latent heat of melting of the frosted ice is used in addition to the cooling operation of the auxiliary cooler , while the defrosting operation of the auxiliary cooler is also performed in an off-cycle manner.
And the low-temperature cooling blown from the main cooler during the cooling operation.
An open showcase operating method, wherein air is sent to an auxiliary cooler during off-cycle defrosting . 2. The open showcase operating method according to claim 1, wherein a total cooling operation time of said main cooler is set to be longer than a total cooling operation time of said auxiliary cooler. . 3. The open showcase operating method according to claim 1, wherein the auxiliary cooler continues the cooling operation for a predetermined time after the defrosting operation of the main cooler is completed. 4. The operating method of an open showcase according to claim 1, wherein intervals of the defrosting operation between a place where the open showcase is installed during business hours and during a non-business hour are different.