JPH0237273A - Operation control method for refrigerated open display case - Google Patents

Abstract

PURPOSE:To keep a disturbance of temperature within a refrigerator as less as possible and save energy as well as to keep a degree of freshness of goods within the refrigerator by a method wherein an amount of blowing air is adjusted in response to a variation of surrounding atmospheric temperature. CONSTITUTION:A blowing port 4 is provided with a blowing air volume sensor 12 and a device 13 for setting a value of disturbance of refrigeration temperature is arranged near an external part of the blowing port 4. In addition, a controller device 15 using a micro-computer is provided, an output signal from the device 13 is fed and a control signal is fed to a device 14 capable of changing an amount of air. When an amount of blown air is detected after a cooling operation is performed, the control device 15 may calculate a present surrounding atmosphere temperature in response to a characteristic of relation among an operation elapsing time, an amount of blowing air and a surrounding atmosphere temperature in reference to the detected value. The control device 15 may calculate a proper amount of blowing air required for getting a value of disturbed temperature within the refrigerator to the minimum value for keeping a degree of freshness of the goods within the refrigerator under the present surrounding atmospheric temperature and then it may output a control signal to the device 14 capable of varying an amount of air connected to a blower 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling the operation of a refrigerated open showcase for displaying and selling products that require refrigeration.

[Conventional technology]

FIG. 6 shows a vertical side view of a conventional refrigerated open showcase. The front side of the main body (1) formed by the heat insulating wall (3) is an opening (2) for entering and exiting products, and the interior of the main body (1) is A duct plate (6) partitions the room into a product display room (10) and a cold air circulation path (7).

A blower (9) and a cooler (8) are arranged in this cold air circulation air passage (7), and each end of the cold air circulation air passage (7) is connected to an air outlet (4) and a suction outlet. The mouth (5) faces the upper and lower ends of the front opening (2). Also, in the figure (11
) indicates product shelves provided in multiple stages in the product display room (10).

In the refrigerated open showcase with such a configuration, the cold air sucked in from the suction port (5) by the blower (9) is cooled by the cooler (8), passes through the cold air circulation path (7), and then exits the air outlet (4). It is blown out from the front opening (2), forms an air curtain at the front opening (2), cools the inside of the product display room (10) to a desired temperature, and is sucked in again from the suction port (5), repeating this circulation. In this case, the amount of air drawn in by the blower (9) and sent to the cooler (8) is always constant.

By the way, even if the amount of air sent by the blower (9) is constant, the amount of air blown out from the outlet (4) depends on the outside temperature,
This relationship changes depending on the elapsed operation time, and the initial air volume W m
When ax is held constant, as shown in the characteristic curve diagram of FIG. 4, the blowout air volume decreases as the operating time T1 elapses, and the degree of the decrease increases as the outside air temperature increases.

Furthermore, as shown in the characteristic curve diagram in Figure 5, the relationship between the blowout air volume, the internal temperature variation value, the required refrigerating power of the showcase, and the outside air temperature is such that as the blowout air volume W increases, the required refrigerating capacity Q increases. (The internal temperature variation value ΔT becomes smaller. Furthermore, when the blowout air volume is kept constant, both the required refrigerating capacity Q and the internal temperature variation value ΔT become smaller as the outside temperature decreases.

(Problems to be Solved by the Invention) In order to maintain the freshness of stored products in the product display room, it is desirable to always maintain the internal temperature variation value ΔT below a certain value.

However, in the past, since the amount of air blown by the blower was constant, for example, in order to set the variation value of the internal temperature to a predetermined value ΔTt5 or less necessary to maintain the freshness of the product, it was necessary to set the variation value of the internal temperature to a predetermined value ΔTt5 or less required to maintain the freshness of the product during the summer when the outside temperature was 25°C. Even under the condition that the predetermined variation value ΔT2. It is necessary to set the air volume to W so that this can be obtained.

For this reason, even in the middle of spring, autumn and winter, when the outside air temperature is lower than in summer, the operation is performed at the air volume of W, and during this period, the internal temperature variation value ΔT is reduced to ΔTZO5ΔTI.
, which is much smaller than the predetermined value ΔTB, and the internal temperature variation value becomes smaller than necessary.

As a result, the minimum internal temperature variation value ΔT2 required to maintain product freshness was determined. This results in conditions that are more sufficient than those obtained under the above conditions, and the extra capacity is consumed by the blower and cooler, which goes against energy-saving measures.

The purpose of the present invention is to solve the above-mentioned disadvantages of the conventional example, and to make it possible to always keep the variation value of the internal temperature at the minimum necessary value in accordance with the outside temperature, maintain the freshness of products, and consume excess energy. An object of the present invention is to provide a method for controlling the operation of a refrigerated open showcase that is useful for energy saving without having to do much.

[Means to solve the problem]

In order to achieve the above object, the present invention divides the interior of the main body, which has an opening for entering and exiting products on the front surface, into a product display room and a cold air circulation path in which a blower and a cooler are installed, using a duct plate.
In the refrigerated open showcase in which the ends of the cold air circulation air path are formed at the air outlet and suction port facing the upper and lower ends of the product inlet/outlet opening, and the opening surface is closed with a cold air curtain, a blowout air volume sensor is provided, The gist of this method is to calculate the outside air temperature from the airflow rate detected by a sensor at the beginning of operation, and then adjust the airflow rate thereafter so that a predetermined internal temperature variation value is obtained under this outside air temperature.

[Function] According to the present invention, based on the fact that the amount of air blown from the outlet decreases as the operating time elapses and as the outside temperature increases, the amount of air blown from the outlet decreases after a predetermined period of time has passed after the start of cooling operation. The outside air temperature is calculated from the airflow rate detected by the sensor, and the airflow rate necessary to obtain the minimum internal temperature variation value is calculated from this outside air temperature, and the cooling operation is performed using this airflow rate. Therefore, the temperature inside the refrigerator is always set to the minimum necessary internal temperature variation value, so the freshness of the products in the refrigerator can be maintained without wasting energy.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a flowchart showing an embodiment of the method for controlling the operation of a refrigerated open showcase according to the present invention, and FIG. 2 is a longitudinal sectional side view of the refrigerated open showcase used in this embodiment.
First, the overall configuration of the refrigerated open showcase will be explained.

In FIG. 2, the same components as those of the conventional example already explained with reference to FIG. 6 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

The basic configuration of the refrigerated oven showcase is the same as the conventional one, but the one used in the method of the present invention is equipped with a blowout air volume sensor ( 12), and the blower (9) disposed in the cold air circulation path (7) is equipped with an air volume variable device (14) using inverter control, phase control, etc. to adjust the air volume.
connected.

Furthermore, an internal temperature variation value setting device (13) for linearly setting the internal temperature variation value as shown in FIG. 3 is provided near the outside of the air outlet (4). This internal temperature variation value setting device (13) is not limited to one that can set the internal temperature variation value linearly, but a device that allows stepwise setting of two or three or more stages using an on-off switch etc. may be used. is also possible.

In general, a control device using a microcomputer, etc.
15), the output signals from the outlet air volume sensor (12) and the internal temperature variation value setting device (13) are introduced into this control device (15), and the control signal from the control device (15) is used to adjust the air volume. It was introduced into the variable device (14).

Next, the operation will be explained.

The cold air sucked in from the suction port (5) by the blower (9) is cooled by the cooler (8) as in the conventional case, and the cold air flow w
The air is blown out from the outlet (4) through the i-ring route 7), forming a cold air curtain at the front opening (2), and
The inside of the product display room (10) is cooled, and the air is sucked in through the suction port (5) again, and this circulation is repeated.

A method for always setting the internal temperature variation value to the minimum necessary value that can maintain the freshness of the stored products in the product display room (10) in this operation will be explained with reference to the flowchart of FIG.

At the initial stage of operation, the internal temperature variation value is set at ΔT tnax so that the minimum internal temperature variation value necessary to maintain product freshness can be obtained even under summer conditions where the outside temperature is high, for example, 25°C. The air volume W is also set to the maximum air volume Wmax.

Cooling operation starts with this set value, and the operation time T (TI =
1 to 3 hours), the blowout air volume sensor (12) detects the blowout air N W T +, and this blowout air 1w a,
is output to the control device (15).

Based on this detected value W, 1, the control device (15) calculates the current outside air temperature Tout based on the relationship between the elapsed operation time, the airflow volume, and the outside air temperature shown in FIG.
out −f (W, TI)).

Based on the outside air temperature Tout obtained in this way, the fifth
The blowout air volume, outside air temperature, and internal temperature variation values shown in the figure,
The current outside temperature Tout depends on the relationship characteristics of the required refrigerating capacity.
Under the following conditions, the control device (15) should calculate the appropriate airflow volume necessary to obtain the minimum temperature variation value Δ'I'zs in the refrigerator to maintain the freshness of the products in the refrigerator.Wfit = f
(Tout, ΔTmax)) and outputs a control signal to the air volume variable device (14) connected to the blower (9).

As a result, the air volume variable device (14) operates, and the air blower (
9) changes the world of the air sent to the cold air flow va loop route 7), (W = Wfit), for example, the temperature variation in the refrigerator is kept constant at ΔT2S, and in this state the freshness of the products in the refrigerator is maintained. When performing maintenance, when the outside temperature changes from 25''C to 20°C, the control device (15) outputs an output to the air volume variable device (14) to change the air volume from Wl to W2.

In this case, if the operation is continued at the air volume W even though the outside temperature has dropped to 20°C, the internal temperature variation value will be ΔT2o, and the internal temperature variation will be greater than necessary to maintain the freshness of the product. The required refrigerating capacity at this time will be Q2°.

However, as mentioned above, the minimum ΔT2. If the air volume is changed to W2 so that it can be kept constant, the required refrigerating capacity will decrease to Q2゛, and energy savings will be achieved by 691 minutes in Fig. 5.

In addition, in the above embodiment, the internal temperature variation set value is
Minimum value ΔT2 required to maintain the freshness of products in the warehouse. However, in order to prioritize energy saving over freshness control and achieve even greater energy savings, the internal temperature variation set value should be set to Δ72. Just set it to FF.

In this case, when the outside temperature is 25°C, the air volume is W.

Also, when the outside temperature is 20°C, the control device (15) outputs an output to the airflow variable device (14) so that the airflow becomes W2'', thereby changing the required refrigerating capacity from Q, I+ to Q2゜. As a result, energy can be saved by the amount of decrease ΔQ +F, and since this amount of decrease ΔQ I+ is larger than the amount of decrease ΔQ' in the above embodiment, the energy can be saved even more.

(Effects of the Invention) As described above, the method for controlling the operation of a refrigerated oven showcase of the present invention always maintains the variation in internal temperature constant by adjusting the blowout air volume in accordance with changes in air temperature. As a result, it is possible to maintain the freshness of the products in the refrigerator without reducing the variation in temperature inside the refrigerator more than necessary, and it is also possible to save energy.

Further, since the internal temperature variation set value can be freely set to any desired value, greater energy savings can be achieved by selecting this set value.

[Brief explanation of the drawing]

Fig. 1 is a control flowchart showing an embodiment of the method for controlling the operation of a refrigerated oven showcase according to the present invention, Fig. 2 is a longitudinal cross-sectional side view of the refrigerated oven showcase used in the method of the present invention, and Fig. 3 shows the main parts of the same. A front view of a certain internal temperature variation value setting device. Figure 4 is a characteristic curve diagram showing the relationship between elapsed operating time, airflow volume and outside temperature. Figure 5 is a diagram showing the relationship between airflow volume and outside air temperature, required refrigerating capacity, and inside temperature. FIG. 6 is a characteristic curve diagram showing the relationship between temperature variation values, and is a longitudinal side view of a refrigerated open showcase used in the conventional operation control method. (], )...Showcase body (2)...Front opening (3)...Insulating wall (4.
...Blowout D (5')...Suction port (6...
Plate to duct 1 (7)...Cold air circulation air path (8...
・Cooler (9)...Blower (10)...Product display room (11)...Product placement shelf (12...Blowout air volume sensor (13)...Internal temperature variation value setting device (14)・
...Air volume variable device (15)...Control device] Figure 2 Figure 3 Figure 4 Figure 5 νV1'NNa', //ifA! z t f? , 6: Down ÷ W

Claims (1)

[Claims] The interior of the main body, which has an opening for entering and exiting products on the front side, is divided by a duct board into a product display room and a cold air circulation path in which a blower and a cooler are installed. In a refrigerated open showcase where the air outlet and suction port facing the upper and lower ends of the opening are closed with a cold air curtain, a blowout air volume sensor is provided, and the blowout air volume detected by the sensor at the initial stage of operation is measured. Calculate the outside temperature,
A method for controlling the operation of a refrigerated open showcase, characterized by adjusting the subsequent blowout air volume so that a predetermined internal temperature variation value is obtained under this outside air temperature.