JP5388336B2 - Control method of refrigerator - Google Patents

Description

  The present invention relates to a method for controlling a refrigerator, and more particularly, to a method for controlling a refrigerator when a plurality of freezing and refrigeration showcases provided in a supermarket or a convenience store are cooled with a single refrigerator.

  Predicts when the compressor of the refrigerator will stop as a refrigeration control system for cooling the cooling target devices such as multiple refrigeration / refrigeration showcases installed in supermarkets and convenience stores with a single refrigerator At the same time, priorities are given to a plurality of cooling target devices, and the control valves are opened in order from the highest priority at the timing when the compressor stops (for example, see Patent Document 1). . Also known is a cooling system that reduces the power consumption of the refrigerator by setting the low pressure setting value of the compressor high when the inside of the refrigerator / freezer showcase is sufficiently cooled. (For example, refer to Patent Document 2).

JP 2008-232535 A JP 2007-10232 A

  However, since the refrigeration control system described in Patent Document 1 controls a control valve (solenoid valve) that supplies refrigerant from the refrigerator to the object to be cooled, the system and wiring become complicated and the cost increases. There was a problem of inviting. In the cooling system described in Patent Document 2, the temperature data and the open / close state of the solenoid valve are used for determination, but the temperature change in the use state of the refrigeration / refrigeration showcase cannot be sufficiently handled. The power consumption of the refrigerator could not be reduced sufficiently.

  Accordingly, an object of the present invention is to provide a refrigerator control method that can perform reliable cooling control with a simple configuration and can sufficiently reduce the power consumption of the refrigerator.

In order to achieve the above object, a control method for a refrigerator according to the present invention is provided when a plurality of freezing / refrigerating showcases each provided with a plurality of freezing / refrigerating showcases are cooled with a single refrigerator. In the control method of the refrigerator, the temperature data of each showcase is sampled at a preset measurement time range and a preset measurement time interval, and the temperature deviates from a preset set allowable value within the measurement time range. The number of data is counted, and when the counted allowable temperature deviation number is less than a preset deviation allowable value, the low pressure set value of the refrigerator is increased, and when the allowable temperature deviation number is equal to or greater than the deviation allowable value, the temperature The load of the showcase whose data deviates from the set allowable value is compared with the load of the entire system to which the showcase belongs, and the showcase is compared. When the calculated load ratio is within the preset system load ratio set value, the low pressure set value of the refrigerator is increased, and the calculated load ratio exceeds the in-system load ratio set value. when that is characterized by lowering the low pressure set value of the refrigerating machine.

Further, in the refrigerator control method of the present invention, when the load ratio exceeds the in-system load ratio set value, the temperature data is set to a set allowable value without immediately lowering the low pressure set value of the refrigerator. The total load ratio of the showcase is calculated by comparing the load of the showcase that deviates from the total load that is the sum of the loads of the systems that are cooled by the refrigerator that cools the showcase. When the load ratio is within the preset total load ratio set value, the low pressure set value of the refrigerator is held, and when the calculated total load ratio exceeds the total load ratio set value, the low pressure set value of the refrigerator is decreased. It is particularly preferred that

  In addition, when the temperature change peaks and valleys of the plurality of freezing / refrigeration showcases overlap, the timing for opening the solenoid valve of at least one of the plurality of freezing / refrigeration showcases overlapping the valleys It is preferable to average the peaks and valleys of the temperature change in the plurality of freezing / refrigeration showcases, and the change of the low-pressure set value is the environmental temperature / humidity of the plurality of freezing / refrigeration showcases and preset seasonal information And referring to time information.

  Further, instead of or simultaneously with increasing the low pressure set value of the refrigerator, the refrigerant compression amount of the compressor mounted on the refrigerator is reduced and the low pressure set value of the refrigerator is decreased. Instead of or simultaneously, the refrigerant compression amount of the compressor can be increased, and the increase / decrease amount of the refrigerant compression amount is a compressor that operates among a plurality of compressors mounted on the refrigerator. Can be done by selecting the number of.

  According to the refrigerator control method of the present invention, since the refrigerator can be controlled by accurately grasping the change in the temperature of the showcase, the showcase can be reliably kept in a cooled state, and the freezer The power consumption of the machine can be reduced efficiently.

It is a block diagram which shows one example of the cooling equipment used as the implementation object of the control method of the refrigerator of this invention. It is a block diagram which shows one example of a controller which implements the control method of the refrigerator of this invention. It is a flowchart which shows one example of the control method of the refrigerator of this invention. It is a figure which shows an example of the temperature change in a some showcase.

  First, a method for carrying out the method of the present invention is a cooling facility that cools each showcase of a plurality of systems each having a plurality of freezing / refrigeration showcases (hereinafter simply referred to as showcases) in parallel with one refrigerator. For example, one first system 10 having four showcases 11, 12, 13, and 14 and one second system 20 having four showcases 21, 22, 23, and 24 are provided. As shown, each showcase is provided with devices such as an evaporator, a solenoid valve, an expansion valve, and a temperature sensor, and the refrigerator 30 includes, for example, Three compressors 31, 32, and 33 are provided.

  The controller 41 for controlling the showcase and the refrigerator includes temperature data from each temperature sensor of each showcase, opening / closing data of each solenoid valve, operation data of each compressor of the refrigerator, and environmental temperature of the showcase. An input unit 42 that reads humidity data and the like and inputs various set values; a storage unit 43 that stores temperature set values, set allowable values, low pressure set values, seasonal information, time information, etc. of each showcase; and an input A determination unit 44 for determining control of a low pressure setting value, control of opening / closing of each solenoid valve, operation control of each compressor, and the like from each data read by the unit 42 and each data stored in the storage unit 43; And an output unit 45 that outputs an opening / closing signal of each solenoid valve, an operation signal of each compressor, and the like based on the determination result in.

  The input unit 42 continuously reads temperature data of each showcase and environmental temperature / humidity data of each showcase, and opens / closes each solenoid valve as open / close data as the solenoid valve open / close data in each showcase. Operation time data when each compressor is turned ON or OFF is read as time data and compressor operation data, and stored in the storage unit 43, respectively.

  In the determination unit 44, the low-pressure set value of the refrigerator is controlled from each temperature data sampled from the showcase of each system (first system 10 in this embodiment) according to the procedure shown in FIG. First, in step S1, the temperature data of each showcase is sampled at a preset measurement time range and a preset measurement time interval. The measurement time range and measurement time interval can be arbitrarily set according to the conditions of the showcase installation location, season, time zone, etc., and the days when the temperature change of the showcase is relatively large due to the ambient load. The measurement time range and the measurement time interval can be shortened during the middle and summer seasons, and the measurement time range and the measurement time interval can be lengthened at night and winter when the ambient load is light and the temperature change is relatively small. For example, if the measurement time range is the same 30 minutes, the measurement time interval is set every 3 minutes in summer and every 5 minutes in winter, or the measurement time range is set to 15 minutes in summer and 30 minutes in winter. Each can be set.

  In step S2, the sampled temperature data, for example, temperature data for 10 times in 30 minutes is compared with a set allowable value set in advance for each showcase, and the fluctuation range of the sampled temperature data is the set allowable value. It is determined whether it is within the range. When it is determined in step 2 that the fluctuation range of the temperature data is within the range of the set allowable value (YES), the process proceeds to step S3 and the low pressure set value of the refrigerator 30 is set in advance from the current low pressure set value. Raise the minute. The control amount of the low pressure set value is arbitrary, and can be set, for example, to increase the low pressure set value in units of 10 kPa.

  If there is temperature data in which the fluctuation range of the temperature data exceeds the set allowable value in step 2 and deviates from the predetermined range (NO), the process proceeds to step S4, that is, the number of temperature data exceeding the set allowable value, ie, The allowable temperature deviation count is counted, and the obtained allowable temperature deviation count is compared with a preset allowable deviation value. As a result of the comparison in step S4, when it is determined that the allowable temperature deviation number is not equal to or greater than the deviation allowable value (NO), the process proceeds to step S3 to increase the low pressure set value. When it is determined that the value is greater than or equal to (YES), the process proceeds to step S5. For example, when the allowable deviation value is set to “2”, when the allowable temperature deviation number is “1”, the process proceeds to step S3, and when the allowable temperature deviation number is “2” or more, the process proceeds to step S5.

  In step S5, the load of the showcase whose temperature data exceeds the set allowable value is compared with the system load that is the load of the entire system to which the showcase belongs (the first system 10 in this example), and the temperature relative to the system load is determined. The load ratio of the showcase whose data exceeds the set allowable value is calculated, and the calculated load ratio is compared with a preset load ratio setting value (A%) in the system. When the calculated load ratio is within the in-system load ratio set value (YES), the process proceeds to step S3 to increase the low-pressure set value, and when the calculated load ratio exceeds the in-system load ratio set value, the process proceeds to step S6. move on. For example, when the load ratio setting value in the system is set to “20%”, when the calculated load ratio is less than 20% of the system load, the process proceeds to step S3, and the calculated load ratio is 20% or more of the system load. Sometimes go to step S6. At this time, even if there are two or more showcases whose temperature data exceeds the set allowable value, the load in the system is calculated by comparing the load of these two showcases with the system load. What is necessary is just to compare a load ratio with the load ratio set value in a system | strain.

  In step S6, the load of the showcase whose temperature data exceeds the set allowable value and the load of each system cooled by the refrigerator 30 that cools the showcase are added together (in this example, the first system 10 and Compared with the total load obtained by adding the load of the second system 20), the ratio of the load of the showcase where the temperature data for the total load exceeds the set allowable value (total load ratio) is calculated, and the calculated total load ratio and Compare with the preset total load ratio setting (B%). When the calculated total load ratio is within the total load ratio set value (YES), the process proceeds to step S7, where the low pressure set value of the refrigerator 30 is held at the current low pressure set value, and the calculated total load ratio is the total load ratio setting. When it exceeds the value, the process proceeds to step S8, and the low pressure set value of the refrigerator 30 is lowered from the current low pressure set value by a preset pressure. For example, when the total load ratio setting value is set to “15%”, the process proceeds to step S7 when the calculated load ratio is less than 15% of the total load, and when the calculated load ratio is 15% or more of the total load. Proceed to step S8. When there are two or more showcases whose temperature data exceeds the set allowable value, the combined load ratio may be calculated in the same manner and compared with the combined load ratio set value. In the second system 20 as well, the low pressure set value is controlled by the same procedure as in the first system 10.

  For example, each load of the showcases 11 to 14 in the first system 10 is 3 kW, 2 kW, 1.5 kW, 1.5 kW, the system load is 8 kW, and each of the showcases 21 to 24 in the second system 20 is When all the loads are 3 kW and the system load is 12 kW, and the temperature data of the showcase 12 (load = 2 kW) of the first system 10 deviates twice within the measurement time range, step S1, step S2, step Proceeding in the order of S4 and step S5, 8 kW which is the system load of the first system 10 and 2 kW which is the load of the showcase 12 are compared. Since the load of the showcase 12 in this case is 25% (2/8), when the load ratio setting value in the system is set to “20%”, the load ratio in the system is 20% or more. Therefore, the process proceeds to step S6 without proceeding to step S3.

  On the other hand, if the showcase in which the temperature data deviates twice within the measurement time range is the showcase 13 with a load of 1.5 kW, the load ratio in the system is 19% (1.5 / 8). Proceeding to S3, the low pressure set value is increased. That is, when the temperature data of a showcase with a small load deviates from the set allowable value, the low pressure set value of the refrigerator 30 is increased to reduce power consumption when the temperature data of other showcases are within a normal range. .

  In step S6, a total load of 20 kW, which is a sum of 8 kW as the load of the first system 10 and 12 kW as a load of the second system 20, and 2 kW as a load of the showcase 12 of the first system 10 is obtained. The total load ratio is calculated by comparison. Since the calculated total load ratio is 10% (2/20), when the total load ratio setting value is set to “15%”, the calculated total load ratio is less than 15%, and thus the process proceeds to step S7. Going forward, the low pressure set value of the refrigerator 30 is held.

  On the other hand, if the showcase in which the temperature data deviates twice within the measurement time range is a showcase 13 with a load of 3 kW, the total load ratio is 15% (3/20), so the total load ratio setting value is When it is set to “15%”, the process proceeds to step S8 to lower the low pressure set value of the refrigerator 30 to eliminate the insufficient cooling.

  In this way, the low pressure set value is increased or decreased depending not only on the presence / absence and number of deviating temperature data, but also in the showcase environment where the temperature data deviates, the load ratio for all showcases, the temperature data deviating state, etc. Therefore, it is possible to reduce the operating time and the number of operations of the compressor when cooling a plurality of showcases of a plurality of systems by a single refrigerator 30 while suppressing unnecessary fluctuations in the low pressure set value. The power consumption of the refrigerator 30 can be effectively reduced without impairing the cooling performance. In this control, the in-system load ratio setting value (A%) and the combined load ratio setting value (B%) can be appropriately set according to various conditions. However, considering controllability, A = It is preferable to set B or A> B.

  Furthermore, the calculation of the fluctuation of the cooling load according to the season and time zone, the change of the low pressure set value, the open / close state of each solenoid valve, and the operation state of the three compressors 31, 32, 33 provided in the refrigerator 30 are calculated as data. By processing, the amount of compression required for a predetermined cooling operation can be derived. Therefore, by optimizing the optimum number of compressors to be operated and the compression capacity in accordance with the obtained compression amount, Power consumption can be further reduced.

  For example, as the three compressors 31, 32 and 33, the first compressor 31 is a compressor capable of adjusting horsepower, and the second and third compressors 32 and 33 are fixed horsepower compressors. Thus, for example, when a compressor adjustable to 2.5 to 10 horsepower is used for the first compressor 31 and a 10 horsepower compressor is used for the second and third compressors 32 and 33 During the summer daytime when the cooling load of the showcase is greatest, the compressor is operated at a maximum capacity of 30 horsepower using all the compressors to increase the refrigerant compression amount, and the cooling load is minimized. During the winter nighttime period, the refrigerant is compressed at 7.5 horsepower, which is 1/4 of the maximum capacity, and the refrigerant compression amount is increased. The basic setting is to operate with horsepower, and the environmental temperature and humidity of the showcase. By controlling the operation horsepower in accordance with the variation of the data and the low-pressure setting value, smaller timing of the load, the power consumption of the refrigerator 30 in the time zone can be reduced without reducing the cooling capacity.

  Also, when the temperature change peaks and valleys in multiple showcases overlap, change the solenoid valve opening / closing timing of one of the showcases, and preferably set the timing of opening the showcase solenoid valve with a small load ratio. By controlling so that both solenoid valves open and close alternately with a slight delay, it is possible to average the peaks and valleys of the temperature change in a plurality of showcases, thereby equalizing the refrigerant flow from the refrigerator. Therefore, the power consumption of the refrigerator can be reduced by reducing the number of ON / OFF times of the compressor.

  For example, as shown in FIG. 4A, the temperature change in the two showcases of the showcase 11 and the showcase 12 increases substantially simultaneously after the electromagnetic valve is turned off and closed, and the electromagnetic When the valve is turned on and opened to enter a cooling operation, and the temperature changes in the same way, the temperature drops repeatedly. When the temperature rises when both showcase solenoid valves are closed, the refrigerant does not flow and the solenoid valve When the temperature drops while both are open, two refrigerants are required. In such a case, as shown in FIG. 4B, control for slightly delaying the closing timing of the solenoid valve of one of the showcases, for example, control for increasing the set temperature for opening the solenoid valve by 0.1 degree When the temperature is lowered by the cooling operation in which the solenoid valve is turned on in one showcase 11 by appropriately repeating the above, the period in which the solenoid valve is turned off and the temperature rises in the other showcase 12 It can be. In this way, by controlling ON / OFF of the solenoid valve so that the peaks and valleys of temperature changes in a plurality of showcases do not overlap, it is only necessary to compress and supply a substantially constant amount of refrigerant in the refrigerator. The compressor can be put into a stable continuous operation state, and the power consumption can be reduced by reducing the number of times the compressor is turned ON / OFF, that is, by reducing the number of times the compressor starts when a large current flows. Can do.

  Also, when the temperature change peaks and valleys in the three showcases overlap, the same control is first performed for one group and two groups, and one temperature change peak and valley After controlling so that the temperature change of the group does not overlap, the temperature change of the two groups should be controlled so as not to overlap while considering the temperature change of one unit By reducing the number of times the compressor is turned ON / OFF by averaging the amount of refrigerant supplied to the showcase as much as possible, and by averaging the operating horsepower of the compressor described above, the operating state of the compressor is also stabilized. The power consumption of 30 can be further reduced.

10 first system 11-14 four showcases of first system 20 second system 21-24 four showcases of second system 30 refrigerator 31-33 three compressors of refrigerator 41 controller 42 input Unit 43 Storage unit 44 Calculation unit 45 Output unit

Claims (6)

In the control method of the refrigerator when cooling and operating each of the plurality of freezer / refrigerated showcases each having a plurality of freezer / refrigerated showcases with one refrigerator,
The temperature data of each showcase is sampled at a preset measurement time range and preset measurement time interval,
Count the number of temperature data that deviated from the preset setting tolerance within the measurement time range,
When the counted allowable temperature deviation number is less than a preset deviation allowable value, increase the low pressure set value of the refrigerator,
When the allowable temperature deviation number is equal to or greater than the deviation allowable value, the load of the showcase is compared by comparing the load of the showcase in which the temperature data deviates from the set allowable value and the load of the entire system to which the showcase belongs. Calculate
When the calculated load ratio is within the preset system load ratio set value, increase the low pressure set value of the refrigerator,
A control method for a refrigerator, wherein the low-pressure set value of the refrigerator is lowered when the calculated load ratio exceeds the in-system load ratio set value . When the load ratio exceeds the in-system load ratio set value, the load of the showcase in which the temperature data deviates from the set allowable value without immediately lowering the low pressure set value of the refrigerator, and the showcase The total load ratio of the showcase is calculated by comparing the total load of each system cooled by the refrigerator to be cooled, and the calculated total load ratio is within a preset total load ratio set value. sometimes the retaining low pressure set value of the refrigerating machine, the calculated sum load ratio is summed load rate when it exceeds the set value, characterized in that lowering the low-pressure setting value of the refrigerating machine of claim 1 refrigerator Control method. When the temperature change peaks and valleys of the plurality of freezing / refrigeration showcases overlap, delay the opening timing of the solenoid valve of at least one of the plurality of freezing / refrigeration showcases overlapping the valleys. 3. The control method for a refrigerator according to claim 1, wherein peaks and valleys of temperature changes in a plurality of freezing / refrigeration showcases are averaged. Change of the low-pressure setting value, and the environmental temperature and humidity of the plurality of refrigerated showcases, any one of claims 1 to 3, characterized in that with reference to the seasonal information and time information set in advance 1 The control method of the refrigerator of claim | item. Instead of increasing the low-pressure set value of the refrigerator, or at the same time, decreasing the refrigerant compression amount of the compressor mounted on the refrigerator and decreasing the low-pressure set value of the refrigerator The method for controlling a refrigerator according to any one of claims 1 to 4 , wherein the refrigerant compression amount of the compressor is increased at the same time or simultaneously. 6. The refrigerator control method according to claim 5 , wherein the amount of increase / decrease in the refrigerant compression amount is performed by selecting the number of compressors to be operated among a plurality of compressors mounted on the refrigerator. .

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