JPH0510588B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method of operating a plurality of cooling devices installed in a prefabricated low-temperature refrigerator or the like.

(b) Conventional technology For example, Japanese Patent Publication No. 17307/1982 discloses a plurality of cooler units for cooling the inside of a low-temperature warehouse, dedicated fans installed for each of these units, and a system that detects the temperature distribution inside the warehouse. and a calculation control device that calculates the cooling load of the warehouse and controls the temperature and amount of refrigerant supplied to the dedicated fan and cooler unit in accordance with the cooling load, A low-temperature warehouse is shown in which a plurality of stirring fans are installed in the warehouse to control the temperature inside the warehouse to a target storage temperature and to even out the temperature distribution inside the warehouse.

(c) Problems to be solved by the invention In the above-mentioned low-temperature warehouse, each cooler unit is controlled based on the detection of the temperature inside the warehouse by a thermometer. It can be kept substantially uniform. However, in this operation, the operation time of any given cooler unit is long, that is, when the cooler unit is operated, the temperature rise near the entrance and exit of the warehouse is large. The ratio is high and the life span is shortened, and not only can each cooler unit not be operated on an average basis, but it also requires more power than necessary to operate the stirring fan and the cooler fan at the same time. A problem also arose in that the load led to an increase in the refrigeration load.

(d) Means for Solving the Problems In order to solve the above problems, the present invention provides a plurality of devices distributed at predetermined intervals in the refrigerator, each equipped with a cooler and a blower. A cooling device, a plurality of temperature sensors paired with the cooling device and distributed in the warehouse, and a control unit that outputs an operation control signal to the cooling device based on the temperature detected by the temperature sensor. In the method of operating a refrigeration system, the cooling system is sequentially operated according to an output from the control unit, wherein a preset temperature in the refrigerator, an override upper limit value that is a predetermined temperature higher than the upper limit value of the preset temperature in the refrigerator; An override lower limit value that is a predetermined temperature lower than the lower limit value of the internal preset temperature is set, and the control unit calculates an average value of the temperatures detected by each of the temperature sensors, and compares this average value with the internal preset temperature. and when the average value reaches the upper limit of the set temperature, the cooling devices are sequentially started at predetermined time intervals, and when the average value reaches the lower limit of the set temperature, the cooling device The cooling devices are stopped at predetermined time intervals in the order in which they started operating, and the respective cooling devices are operated based on rotation, and when the measured value by any temperature sensor reaches the override upper limit value, the temperature The cooling device paired with the sensor is operated regardless of rotation, and when the measured value by any temperature sensor reaches the override lower limit value, the cooling device paired with the arbitrary temperature sensor is rotated. A method of operating a refrigeration equipment characterized by stopping the refrigeration equipment regardless of the

(E) Effect Rotation control is applied to the operation and stop of a plurality of cooling devices, and the cooling devices in areas where the override upper limit is exceeded are operated regardless of the rotation, and cooling devices in areas where the override lower limit is exceeded are controlled. Some cooling devices shut down regardless of the rotation.

(f) Embodiment An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 4.

FIG. 2 is a schematic plan view of a prefabricated low-temperature refrigerator. 1 is a side wall formed by combining a plurality of heat insulation panels, and an opening 3 for storing and carrying out stored products is formed in the side wall 1. It is closed by a heat insulating door 4 so as to be openable and closable. Further, 5 to 10 are first to sixth cooling devices suspended from the ceiling wall of the refrigerator. For example, the first cooling device 5 includes a cooler 5A that exchanges heat with cold air inside the refrigerator, and a cooler 5A that circulates this cold air. The second to sixth cooling devices 6 to 10 are also provided with a cooler and a blower (both not shown).
Further, first to sixth temperature sensors 11 to 16 such as a thermistor or a transistor sensor are provided near the first to sixth cooling devices 5 to 10, which are paired with the respective cooling devices and detect the internal temperature of the refrigerator. There is. Note that the first to sixth temperature sensors 11 to 16 may be provided at the cold air suction ports of the respective cooling devices.

Further, FIG. 1 is a block diagram of a control circuit for controlling the operation of the cooling device, and the same reference numerals as in FIG. 1 are the same, and a detailed explanation will be omitted.

S is a control unit, 17 is the first to sixth temperature sensor 1
A sensor input circuit that counts and sequentially outputs the output signals 1 to 16 (voltage-frequency converted signals); 18 is operated to the first to sixth cooling devices 5 to 10;
A control signal output circuit that outputs a stop signal,
19 is an interface that inputs the output of the sensor input circuit 17 and outputs it to the control signal output circuit 18; 20 is a display unit that displays the average temperature inside the refrigerator, the operating status of each cooling device, etc. based on the output of the interface 19; , 21 sets each setting value, each display function, etc., and sends the signals to the interface 19.
22 is a microcomputer unit (hereinafter referred to as microcomputer unit) that exchanges data with the interface 19;
It is. Here, the microcomputer section 22 includes a CPU (central processing unit) 22A,
RAM (random access memory) 22B, and
Equipped with ROM (read only memory) 22C,
The RAM 22B stores the detected temperature, the set temperature inside the refrigerator, and the upper and lower limits set above the set temperature inside the refrigerator, that is, the override upper limit and the override lower limit, and the ROM 22C stores the formula for calculating the average temperature. I remember. And CPU22
For example, A calculates the average temperature using the detected temperature stored in the RAM 22B and the average temperature calculation formula stored in the ROM 22C, compares the average temperature with the set temperature, etc. 5-1
Outputs a 0 operation signal, a stop signal, etc. In addition, the above-mentioned override utilizes the temperature change between the temperature inside the refrigerator and the temperature of the stored items, that is, the poor ability to follow changes in the temperature of the stored items, and saves power on power elements such as cooling equipment. It was established to achieve this goal.

Hereinafter, a method of operating the refrigeration system will be explained with reference to FIGS. 3 and 4. In Fig. 4, the 〇 and △ marks indicate operation and stop of the cooling device, respectively, and the arrow above the △ mark indicates the stop of the cooling device due to override when the internal temperature drops, and the arrow above the 〇 mark The arrows indicate the operation of the cooling device by override when the temperature inside the refrigerator rises.

The operation of the first to sixth cooling devices 5 to 10 includes the first to sixth cooling devices 5 to 10.
This is performed by comparing the average value of the temperatures detected by the sixth temperature sensors 11 to 16 with a set temperature (for example, the set value is set to -10°C and the temperature differential is set to 2°C), and for example, at time A. First to fifth cooling devices 5 to 9
is operating, the average temperature gradually decreases (as shown at Y in FIG. 3), and when the average temperature is within the set temperature at time B, the first to fifth cooling devices 5 to 9 continues operation. It is assumed that the first to fifth cooling devices 5 to 9 start operating in order starting from the first cooling device 5. Then, when the average temperature reaches the lower limit of the set temperature at time C, the microcomputer section 2
The output of step 2 changes and at this point, the extraction time T ₁ begins, a count is started, and when the preset extraction time, e.g. 1 minute, has elapsed from time C and reaches time D, the average temperature and lower limit value If the average temperature is still lower than the lower limit, the microcomputer unit 22
outputs an operation stop signal via the interface 19 and the control signal output circuit 18.
After outputting to the cooling device 5, the first cooling device 5 stops operating. Further, as shown by a dashed line 15A in FIG. 3, the temperature detected by the fifth temperature sensor 15 gradually decreases, and at time E, the temperature reaches an override level that is, for example, 1°C lower than the lower limit value which is the set value of the set temperature. When the temperature drops to the lower limit, the microcomputer unit 22 that has input the temperature signal outputs a signal to stop the operation of the fifth cooling device 9, and at that point, the fifth cooling device 9 stops operating.
Thereafter, the internal temperature around the fifth cooling device 9 gradually increases. Moreover, when the extraction time T ₁ has elapsed from time D and reaches time F, the microcomputer section 22 again compares the average temperature with the lower limit value, and if the average temperature is lower than the lower limit value, the second cooling device 7 Stop driving.
Note that the average temperature gradually increases after a while after the fifth cooling device 9 stops operating. Then, when the average temperature is still lower than the lower limit value at time G after the extraction time _T1 has elapsed from time F, the third cooling device 7 stops operating. If the average temperature becomes higher than the lower limit value before the extraction time elapses from time G, the cooling device will not be stopped thereafter.

When the average temperature gradually increases and, for example, at time _G1 , the average temperature is within the set temperature, no cooling device starts or stops operating, and only the fourth cooling device 8 continues to operate. Furthermore, the average temperature gradually increases with the passage of time, and when the average temperature reaches the upper limit of the set temperature at time H, the extraction time T ₁ begins at this point and counting is started. Further, at time I, when the fifth temperature sensor 15 detects that the temperature around the fifth cooling device 9 has reached the upper limit value, for example, −8° C., the microcomputer section 22 outputs an operation signal to stop the fifth cooling device 9. starts driving. Then, when the extraction time has elapsed from time H and time J arrives, and at this time the average temperature is higher than the set temperature, the sixth cooling device 10, which had stopped operating since time A, starts operating according to the operation signal from the microcomputer section 22. Start. Also, time J
If the average temperature is higher than the upper limit value at time L when the extraction time T ₁ has elapsed, the first cooling device that stopped operation first among the first to fifth cooling devices 5 to 9 at time D An operation signal is output from the microcomputer unit 22 to the first cooling device 5, and the first cooling device 5 starts operating. or,
When the ambient temperature of the second cooling device 6, which has stopped operating at time F, increases, the temperature detected by the second temperature sensor 22 gradually increases as shown by the two-dot chain line 12A in FIG. Then, at time K before time L, when the detected temperature reaches an override upper limit value that is, for example, 1°C higher than the upper limit value of the set temperature, an operation signal is output from the microcomputer section 22 to the second cooling device 6, and the second cooling device 6 starts driving.

Thereafter, when the average temperature becomes lower than the upper limit value before the extraction time elapses from time L, the same cooling operation as at time L is continued, and for example, at time M, the third cooling operation is continued.
The cooling devices other than cooling device 7 are in operation. When the average temperature reaches the lower limit at time N, the extraction time T ₁ begins and counting begins.
When the extraction time has elapsed from time N to time O, and the average temperature is lower than the lower limit, the microcomputer unit 22 outputs an operation stop signal to the fourth cooling device 8, which had been operating since time A, and the fourth cooling The device 8 stops operating. Time Q after extraction time T ₁ has elapsed since time O
When the average temperature is lower than the lower limit value, the fifth cooling device 9, which operates for a long time, stops operating in response to a signal from the microcomputer section 22 in the same way as the fourth cooling device 8.
Further, when the temperature detected by the second temperature sensor 12 reaches the lower limit value due to a decrease in the ambient temperature of the second cooling device 6 at time P, the microcomputer unit 22
An operation stop signal is output to the second cooling device 12, and the second cooling device 12 stops operating. When the average temperature is lower than the lower limit value at time R, the sixth cooling device 10 further stops operating.

After that, the temperature inside the refrigerator is controlled by the first to sixth cooling devices 5 to 10.
The defrosting operation of the first to sixth cooling devices 5 to 10 is maintained substantially constant by the operation and stop of the cooling devices, and the defrosting operation of the first to sixth cooling devices 5 to 10 is performed all at once, for example, at predetermined time intervals. Moreover, when a disconnection occurs among the first to sixth temperature sensors 11 to 16,
The microcomputer section 22 outputs an operating signal to the cooling device paired with the temperature sensor in which the disconnection occurred, and the cooling device continues to operate. The average temperature is calculated to control the operation of each cooling device.

Therefore, the microcomputer section 22 controls the first to sixth temperature sensors 11 to 16 provided near the respective cooling devices.
The average value of the internal temperature detected by the controller is compared with the set temperature, and if the average temperature exceeds the upper limit value, the first to
The sixth cooling devices 5 to 10 are started in the order in which they were stopped, and when the average temperature exceeds the lower limit, the first to sixth cooling devices 5 to 10 are stopped in the order in which they were started, and rotation is started. Since the operation is started and stopped based on the above, for example, even when the temperature inside the refrigerator stops rising due to the start of operation of one cooling device, multiple cooling devices do not start operating all at once. It is possible to eliminate unnecessary cooling operations, and when the temperature inside the refrigerator drops, the operating cooling devices will stop operating one after another. The temperature inside the warehouse does not rise, and the temperature inside the warehouse changes slowly, making it possible to minimize changes in the temperature of stored products. In addition, since the first to sixth cooling devices 5 to 10 are operated substantially uniformly, aging changes due to the operation of each cooling device can be made substantially uniform, and frost formation on each cooling device is also substantially uniform. This makes it possible to defrost quickly without leaving any ice or frost during defrosting operation. Moreover, the ambient temperature of the first to sixth cooling devices 5 to 10 increases or decreases, causing the first to sixth temperature sensors 11 to
When the detected temperature of No. 16 exceeds the upper limit or lower limit of the set temperature and reaches the override upper limit or override lower limit, the cooling device that has reached it starts or stops operation regardless of the rotation, and therefore, By stopping the operation, there is no unnecessary operation of the cooling device, and the power load can be saved, and the temperature inside the refrigerator does not increase or decrease significantly in one part, and the temperature can be controlled to be almost uniform throughout the refrigerator. It is possible to maintain the quality of stored products in a substantially uniform and good condition.

(G) Effects of the Invention Since the present invention is a method for operating a refrigeration system as described above, the operation of a plurality of cooling systems is sequentially started in the order in which the operations were stopped, and the operations are stopped in the order in which the operations are started. Since each cooling device is operated and stopped based on the rotation, multiple cooling devices are operated almost uniformly, and the power load can be averaged. Not only can changes over time due to operation be made almost uniform, but the frost on each cooling device is also almost uniform, and it is possible to avoid situations such as an extremely large amount of frost on only a specific cooling device. The defrosting operation of each cooling device can be performed promptly, and when the temperature inside the refrigerator increases, the cooling devices can be operated one after another without operating all at once, and unnecessary cooling operations can be eliminated. When the temperature inside the warehouse drops, the cooling devices are stopped one after another to slow down the change in the temperature inside the warehouse and reduce changes in the temperature of stored products,
In addition, since an override upper limit value and an override lower limit value are set in addition to the set temperature, it is possible to perform temperature control based on stored items while saving power on the power load. In addition, the override lower limit value can prevent stored products from becoming too cold.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the present invention,
Figure 1 is a block diagram of the operation control circuit, Figure 2 is a schematic plan view of a prefabricated low-temperature refrigerator, Figure 3 is a temperature transition diagram showing changes in the average internal temperature, etc., and Figure 4 is the same as Figure 3. FIG. 6 is a diagram showing the operating state of the first to sixth cooling devices as the temperature changes. 5 to 10...First to sixth cooling devices, 5A...Cooler, 5F...Blower, 11 to 16...First to sixth temperature sensors, S...Control unit.

Claims (1)

[Claims] 1 Distributed at predetermined intervals within the refrigerator,
a plurality of cooling devices each equipped with a cooler and a blower; a plurality of temperature sensors paired with the cooling devices and distributed within the warehouse; and a control unit that outputs an operation control signal to the cooling device, and in which the cooling device is sequentially operated according to the output from the control unit, the method comprising: a preset internal temperature; and an upper limit value of the preset internal temperature. setting an override upper limit value that is higher by a predetermined temperature and an override lower limit value that is lower by a predetermined temperature than the lower limit value of the set internal temperature, and calculating an average value of the temperatures detected by the respective temperature sensors in the control unit; In addition, this average value is compared with the set temperature in the refrigerator, and when the average value reaches the upper limit of the set temperature, the cooling device is sequentially started at predetermined time intervals, and the average value is set as the set temperature. When the lower temperature limit is reached, the cooling devices are stopped at predetermined intervals in the order in which they were started;
The respective cooling devices are operated based on rotation, and when the measured value by any temperature sensor reaches the override upper limit value,
The cooling device paired with the arbitrary temperature sensor is operated regardless of the rotation, and when the measured value by the arbitrary temperature sensor reaches the override lower limit value, the cooling device paired with the arbitrary temperature sensor is operated. A method of operating a refrigeration system characterized by stopping the system regardless of rotation.