JPS61191852A - Method of operating showcase - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of operating a freezer or refrigerated showcase that controls the refrigeration equipment of the showcase to maintain an optimal temperature inside the refrigerator and save power. In addition to controlling temperatures suitable for business and non-business hours, we also control temperature based on the product load by stopping the supply of liquid refrigerant to the evaporator intermittently at arbitrary times during cooling operation. There is a particular thing.

The present invention will be explained in detail below with reference to the drawings.

Figure 1 (1) shows the opening (3) for storing and taking out products on the front.
A freezing or refrigerating showcase whose main body is composed of an insulating wall (2) formed with (
7), a second passageway (8) in which a refrigerator is installed, a plurality of shelves (9), and a plurality of lights (10) such as fluorescent lights.
), and both the air outlet and suction ports (12), (13), (14), and (15) of the both roads facing each other are formed at both upper and lower ends of the opening, and both the first and second passages (6) are formed. As shown by the arrows in (8), a two-layer air curtain (Al) (A2) with different temperatures is formed in the opening (3) by the cold air current and protective air current circulated by both the wind losses (5) and (7), respectively. Inside the refrigerator (1
1). Surrounded by orange dashed line (16)
is a refrigeration system, which includes a refrigerant compressor (17) □ condenser (18) □
Liquid solenoid valve (19') - one-degree expansion valve (20) □ Evaporator (4) □ Compressor (17) connected in a ring to compress refrigerant □
It constitutes a known refrigeration cycle that performs condensation, liquefaction, depressurization, and evaporation.

(21) is a control device that controls the temperature inside the refrigerator (11);
A temperature sensor (22) that constantly detects the temperature of cold air in the showcase and a liquid electromagnetic valve (19) that controls the supply of liquid refrigerant to the evaporator (4) are connected to the device.

As shown in No. 2150, this device has a power supply (23) and a processing section (23) which has built-in comparison and timer functions and compares each signal.
4>, a setting section (25) that stores each temperature setting value to be controlled and outputs a signal with a time width corresponding to the temperature inside the warehouse (11), and The day/night switching section (26) that outputs a signal for business or non-business hours, the temperature sensor (22), and the signal from the processing section turn on/off.
and an output section (27) that turns off and controls the opening/closing operation of the liquid electromagnetic valve (19).

Showcase (1) with next control device (21)
Each temperature control will be explained with reference to FIGS. 3 to 5. In each figure, (Ll) is the temperature curve of the circulating cold air detected by the temperature sensor (22), (L,) is the signal waveform of the output part (27) that controls the opening and closing of the liquid solenoid valve (19), and (L) is the temperature curve of the circulating cold air detected by the temperature sensor (22). , ) is the signal waveform of the day/night switching unit (26), (TS) is the lower limit setting value during business hours, (TD) is the upper limit setting value during business hours, (TN) is the lower limit setting value during non-business hours, (TD '
) is the upper limit setting value during non-business hours, (6 lights) is the lighting (1 light)
0) shows the temperature range of automatic setting change at night when the lights are turned off.

Figure 3 shows the characteristics of both on/off and night setback control, and when the day/night switching signal (L,) is OFF, that is, during store business hours when the light (10) is on, the lower limit setting value ( TS) turns off the output signal (Lc).

The output signal (L,
) is turned ON to perform on/off control repeatedly, and as the day/night switching signal (L, ) is turned ON, the output signal (L is turned OFF).
F, the liquid solenoid valve (19) is forcibly closed and the night setback, which is called automatic night setting change, is performed, and the lighting (19) is switched on.
0) is off during non-business hours of the store, the lower limit constant value (
TN) to turn off the output signal (L, ) and set the upper limit value (rD
') turns on the output signal L) to perform on/off control.

Figure 4 shows the characteristics of on/off, night setback, and duty cycle control. During business hours, the timer of the processing unit (24) outputs the output signal (L, ) to perform daytime duty cycle control in which the liquid solenoid valve (19) is forcibly closed during on-off control and the supply of liquid refrigerant to the evaporator (4) is intermittently stopped; During non-business hours, the period (τ) is (τ,)((τ
A〉(τ,)) output signal (L,) is set to 0FFL to turn on/off, night setback, and force the liquid solenoid valve (
19) is closed and the liquid refrigerant to the evaporator (4) is intermittently stopped to control the nighttime duty cycle. This duty cycle is longer (τ8) during non-business hours when the lights (10) are off than during business hours (TS).
It will be held in

FIG. 5 shows the override characteristics in duty cycle control, where (TR) shows the duty cycle temperature width and (L4) shows the override signal waveform. Showcase (when cooling operation is stopped due to duty cycle)
1) The temperature inside may rise as shown by the chain line, which may adversely affect the product load. In this case, during the cooling operation stop time ((τ, ) during the day and (τN) at night), the temperature ((Ts)
+ (TR) or (TN) + (TR)), the output signal (1,) immediately turns ON and performs an override to forcibly return to cooling operation. Furthermore, cooling operation with the next duty cycle is performed. To stop, the temperature drops to (S) or (TN) ((τ) - (τ, ) or (1) - (τ
, )).

Therefore, according to the operating method of the showcase (1),
When the store is not open, when the lighting (10) is turned off and the heat generated by the lighting does not become a refrigeration load, the heat generated by the lighting (10) can reduce the refrigeration load compared to when the store is open, when the heat generated by the lighting (10) becomes a refrigeration load. Therefore, it is possible to operate the refrigeration system (16) under a light load by setting the temperature inside the refrigerator during non-business hours higher than the temperature inside the refrigerator during business hours. Since the supply of liquid refrigerant to the evaporator (4) is intermittently stopped for an arbitrary period of time within the range exceeding the set value of
During this period, the refrigeration equipment (16)
In addition to reducing the operating rate of the evaporator (4) and contributing to power saving, the frost adhering to the evaporator (4) is reduced by the evaporation effect of forced circulation cold air, reducing the ratio of the amount of frost to the evaporator (4). It is possible to reduce the number of times of defrosting by reducing the number of defrosts.

[Brief explanation of the drawing]

The drawings show an embodiment of the method of operating the showcase of the present invention,
FIG. 1 is a longitudinal sectional view of the showcase, FIG. 2 is a block diagram of the control device, and FIGS. 3 to 5 are characteristic diagrams showing the operation of the control device. (4)...Evaporator, (5)...Blower, (10
)...Lighting, (11)...Interior, (21)...
Control device, (22)...Temperature sensor, (24)
...processing section, (25)...setting section, (26).
... Day/night switching section, (27)... Output section. Applicant Sanyo Electric Co., Ltd. and 1 other representative Patent attorney Shizuka Sano Mistakes Figure 4 Figure 2 Figure 3

Claims (1)

[Claims] 1. In a showcase where cold air that has been heat exchanged with an evaporator is forcedly circulated by a blower to cool the inside of the store to a predetermined temperature, the inside temperature of the store during non-business hours is lower than the set value of the inside temperature when the store is open. While cooling the inside of the refrigerator to the respective set values during business hours and non-business hours by increasing the set value of A method of operating a showcase in which supply of liquid refrigerant to the evaporator is intermittently stopped.