JP5363046B2 - Power consumption control device, cooling system, and power consumption control method - Google Patents

Description

  The present invention controls the state of a plurality of loads that consumes electric power for cooling the inside or the room to a predetermined temperature against a change in outside air temperature, such as a freezer, a refrigerator, or an air conditioner. The present invention relates to a power consumption control device and a power consumption control method. In particular, the present invention relates to a technique for reducing the basic charge of a contract when a contract for performing demand control is made between a power consumer and a power company.

  In the temperature control of the load, the influence of the outside air temperature is large. In particular, the average temperature is high in the summer, and the outdoor temperature often peaks during the summer from 1 pm to 3 pm. Of course, the power consumption of the load also peaks during these times. Greet.

  Contract electric power is determined in order for an electric power consumer to receive electric power supply from an electric power company through a receiving / transforming facility. A maximum demand meter is used to monitor contract power. The maximum demand (maximum demand power) is the maximum value of the demand (demand power) average value within a predetermined period of one month (normally about 20 to 30 minutes depending on the terms and conditions).

  The contract power determines the basic charge of the power charge. In other words, as a power consumer, if the monthly maximum demand can be reduced, the contracted power can be lowered, which will be advantageous in that the power charge will be reduced.

  Conventionally, a demand control method is used in order to avoid an increase in the maximum demand. Each time a demand signal is output from the maximum demand meter, predetermined loads are sequentially stopped one by one. According to this, power consumption control is not performed until the demand signal is output, and only a short time (about 20 minutes) is output after the demand signal is output, so the effect of suppressing power consumption is limited. And very few.

  In addition, the load state where the demand signal is output and stopped this time is not considered at all. For example, if the load is a refrigerator or a freezer, and the load is forcibly stopped while the temperature in the store is relatively high, then the temperature in the store will rise abnormally and This may lead to a situation in which the quality of the food stored in the container deteriorates (for example, changes in quality, corruption, etc.).

  Now, patent document 1 (Unexamined-Japanese-Patent No. 2000-23729) discloses the point which interposes a power-saving control apparatus between a some load and a demand control apparatus, and the point which implements prediction of power consumption.

  Patent Document 2 (Japanese Patent Laid-Open No. 11-206014) discloses that power control is performed by providing each load with a temperature sensor that detects the temperature in each load.

  Further, Patent Document 3 (Japanese Patent Laid-Open No. 2006-349302) discloses a point that interrupts and cancels a signal for forcibly stopping a load.

  However, with any conventional technique, the power consumption is only controlled after the output of the demand control signal, and the peak power consumption is controlled to be lower than the level at which the demand control signal is output. It hasn't been done yet.

In other words, it cannot be said that the conventional technology can cope with the problem of actively reducing the basic charge of the power charge.
JP 2000-23729 A JP-A-11-206014 JP 2006-29693 A

  Therefore, an object of the present invention is to provide a power consumption control device and related technology capable of more actively suppressing the peak of power consumption while suppressing deterioration of states in a plurality of loads.

  A power consumption control apparatus according to a first aspect of the present invention is a power consumption control apparatus that is connected to a control unit that inputs a demand signal and controls operation / stop of a plurality of loads controlled by the control unit according to a set temperature profile. The power consumption control device includes a profile storage unit that stores a set temperature profile, and the set temperature profile stored in the profile storage unit includes a first set temperature and a peak time in a peak time zone in which power consumption peaks. Including the second set temperature in the preceding cooling time zone set immediately before the zone and the normal set temperature in the time zone that is neither the peak time zone nor the preceding cooling time zone, and the average value of the first set temperature is normally The average value of the second set temperature is lower than the normal set temperature.

  With this configuration, prior to the peak time zone, control is performed at the second set temperature that is lower than the normal set temperature in the preceding cooling time zone. That is, before entering the peak time zone, the load is cooled more than the normal set temperature, and as a result, the object to be cooled that is cooled by the load is pre-cooled and cooled down before the peak time zone.

  And if it enters into a peak time slot | zone, preset temperature will become 1st preset temperature higher than normal preset temperature, and the power consumption in a peak time slot | zone will be suppressed. As a result, the number of cases where it is not necessary to output the demand control signal increases, and as a result, the contract power can be lowered, which can contribute to the reduction of the basic charge of the power charge. Even in this case, the object to be cooled is pre-cooled in the preceding cooling time zone and is in a state of being completely cooled, and normally, the object to be cooled is thermally disconnected from the outside by a heat insulating material or the like. The temperature does not increase so much, and the quality of the object to be cooled is less likely to deteriorate.

  The power consumption control device according to the second aspect of the present invention further includes a history storage unit that stores the current power consumption state, and the set temperature profile is determined with reference to the history of the power consumption state stored in the history storage unit. The

  With this configuration, the actual power consumption state is accumulated in the history storage unit, and the set temperature profile is determined to reflect the actual power consumption state. Therefore, the set temperature profile can be determined more accurately, and the result As a result, the accuracy of power consumption control can be improved.

  In the power consumption control device according to the third aspect of the invention, the set temperature profile includes a set temperature that is set higher than the normal set temperature in the night and morning time zones.

  With this configuration, power consumption can be more actively reduced at night and in the morning when the outside temperature is low and power consumption is low.

  In the power consumption control device according to the fourth aspect of the present invention, each of the plurality of loads includes a temperature sensor that detects the temperature of each load, and the power consumption control device focuses on the current set temperature defined by the set temperature profile. When the temperature of each load detected by the temperature sensor is higher than the current set temperature by the first temperature range, the load is commanded to each load, and the power consumption control device determines the current set temperature determined by the set temperature profile. When the temperature of each load detected by the temperature sensor with respect to the center becomes lower than the current set temperature by the second temperature range, the load is ordered to stop each load, and the second temperature range is the first temperature range. It is set narrower than the width.

  With this configuration, by detecting the temperature of each load with the temperature sensor, it is possible to suppress the deterioration of the quality of the cooling target cooled by each load. Furthermore, since the second temperature range is narrower than the first temperature range, in the control centering on the current set temperature, the load transitions from operation to stop earlier, and power consumption by the load can be suppressed accordingly. .

  According to the present invention, the number of cases where a demand control signal is not output increases, and it becomes possible to lower the contract power and lower the basic charge of the power charge. Even if it does in this way, since it is in the state cooled down in the preceding cooling time slot | zone, the temperature of cooling object is hard to raise, and there is little possibility that the quality of cooling object deteriorates.

  Further, the set temperature profile can be determined with high accuracy reflecting the actual power consumption state, and the accuracy of power consumption control can be improved.

  Further, in the control centering on the current set temperature, the load is shifted from the operation to the stop early, and the power consumption can be suppressed.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a cooling system using a power consumption control device according to an embodiment of the present invention. In this cooling system, the temperature control that has been individually supported can be collectively managed by the program controller 2 and the total load can be controlled in total to control peak cuts in power consumption in areas that were impossible until now. It is what.

(load)
In this cooling system, a plurality of loads are collectively controlled. A typical load is a refrigerator, a freezer, etc., in which the objects to be cooled (foodstuffs, etc.) are housed and the objects to be cooled in the warehouse are thermally insulated from the outside by a heat insulating material. May be included. In the example of FIG. 1, the loads are all refrigerators 10, 20, and n 0, and temperature sensors 11, 21, and n 1 are provided therein, and the internal temperature signals T 1, T 2, and Tn of each load are the temperature regulator 12. , 22, and n2. As the temperature sensors 11, 21, n1, a resistance temperature detector is preferably used. Of course, as shown in FIG. 1, not only three loads but also a larger number of loads can be controlled collectively.

(Load control unit)
The load control unit is centered on the control unit 1 that inputs a demand signal from an electric power company. The temperature regulators 12, 22, and n 2 output load data d 1, d 2, and dn including the internal temperatures of the refrigerators 10, 20, and n 0 to the control unit 1. The control unit 1 performs control according to the flowchart described later, and as a result, the start / stop circuits 13, 23, and n3 connected to the refrigerators 10, 20, and n0 are respectively operated / stopped signals c1, c2, cn is output, and the start / stop circuits 13, 23, and n3 change the refrigerators 10, 20, and n0 to the “run” state or the “stop” state in accordance with the run / stop signals c1, c2, and cn. Note that conventional loads and load control units may be employed as they are.

(Power consumption control unit)
This part is the core of the cooling system. Although a detailed control process will be described later, a program controller 2 is connected to the control unit 1 of the load control unit. The program controller 2 includes a temperature sensor 3 that detects an outside air temperature and outputs an outside air temperature signal T0, a timer 4 that outputs the current time, a profile storage unit 5 that stores information on a set temperature profile, and a power consumption A history accumulating unit 6 that accumulates the history as needed is connected.

  The program controller 2 includes, for example, a combination of a microprocessor and a ROM that stores a control program.

  Among these, as the profile storage unit 5 and the history storage unit 6, a storage medium such as a flash memory or a hard disk device can be preferably used.

  Further, if the program controller 2 is provided with a communication port to the network (for example, the Internet or the like) 7, the current control state is browsed by the external personal computer 8 via the network 7, or the program controller 2 It is also possible to issue settings, instructions, etc.

(Set temperature profile)
Next, the set temperature profile in this embodiment will be described with reference to FIGS. 2 (a) and 2 (b). Here, FIG. 2 (a) is a graph illustrating the transition of power by the power consumption control method in one embodiment of the present invention, and FIG. 2 (b) is the power consumption in one embodiment of the present invention. It is a time chart which illustrates transition of preset temperature by a control method.

  A one-dot chain line in FIG. 2A shows an example of the progress of power consumption in the summer. In this example, it is by the refrigerator equipment user of contract electric power 500kVA. In the morning and late at night, the power consumption is at a low level of 200 kVA, but the power consumption increases toward noon and peaks around 1 pm to 3 pm, exceeding the 500 kVA demand control line. . After that, power consumption has dropped to a low level of 200 kVA.

  When the conventional demand control method is adopted in such an example, control is performed only in the peak time zone from 1:00 pm to 3:00 pm, and the power consumption is a result of undulations above and below the demand control line (see broken line). .

  On the other hand, in this embodiment, a set temperature profile as shown in FIG. The “set temperature” here is the center of the internal temperature of each of the refrigerators 10, 20, and n0. For reference, in the prior art, the set temperature is constant regardless of whether it is a peak. In the present embodiment, referring to the state of power consumption stored in the history storage unit 6, first, a peak time zone (between times t3 and t4) is determined. Further, a preceding cooling time zone (between times t2 and t4) prior to the peak time zone is determined. In the example of FIG. 2, the time t2 = noon, the time t3 = 1: 00 pm, and the time t4 = 3: 00 pm are merely examples, and various changes may be made.

  The normal set temperature T0 is determined, and the set temperature T2 in the preceding cooling time zone is determined such that T2 is lower than T0 by an average value. Further, the set temperature T3 in the peak time zone is determined so that T3 is higher than T0 by an average value. In the example of FIG. 2B, the set temperature changes stepwise in both the preceding cooling time zone and the peak time zone. This is because, in this example, three signal lines (a total of 8 bits if each line is “0” or “1”) are used, which is merely an example. For example, it may be changed more finely or may be changed more roughly. In short, the average value may be as described above, and as long as it is included in the present invention. It should be noted that a different set temperature profile may be used for each load, and one set temperature profile may be used in common if all the loads are of the same type (for example, a refrigerator). Further, various methods such as changing the set temperature profile for each season can be considered.

  In addition, the set temperature T1 at midnight (after time t5) and in the morning (until time t1) is set to be higher than the normal set temperature T0 so that more power can be saved. Furthermore, the set temperature profile of the next day is determined at a fixed time t6 at midnight.

  In this way, the power consumption progresses as shown by the solid line in FIG. That is, before entering the preceding cooling time zone from the morning, it is not much different from the normal state (dashed line). However, when the preceding cooling time zone is reached, the average value of the set temperature decreases from T0 to T2, and the interior is rapidly cooled. As a result, both the cooling object stored in the refrigerator and the refrigerator itself are cooled more strongly than usual and are in a cold state. For this reason, as clearly seen in the vicinity of the preceding cooling time zone in FIG. 2 (a), the power consumption temporarily rises in the preceding cooling time zone, and the solid line looks like rising up. However, the preceding cooling time zone is short, and even if it rises, it does not exceed the demand control line.

  On the other hand, when shifting from the preceding cooling time zone to the peak time zone, the average value of the set temperature rises from T2 to T3. As a result, the power consumption is lower than the preceding cooling time period. For this reason, as clearly seen in the vicinity of the peak time zone of FIG. 2 (a), the power consumption decreases in the peak time zone, and the solid line looks like it rises downward when viewed from the preceding cooling time zone. The level will be lower than the demand control line. Therefore, power consumption at the peak can be greatly reduced. On the other hand, since both the refrigerator itself and the cooling target are in a state of being completely cooled in the preceding cooling time period prior to the peak time period, the temperature of the refrigerator itself and the cooling target does not readily rise, and the quality of the cooling target is deteriorated. There is very little risk of it occurring.

  And if it passes the peak time zone, it will not be much different from the normal state (dashed line) until midnight. As is clear from the above description, it is easy to obtain a result that the power consumption does not reach the demand control line throughout the day. In other words, the contracted power can be reduced, and the basic charge of the power charge can be lowered.

  Next, after the current set temperature is determined by the set temperature profile set as described above, the “operation” / “stop” control centering on the current set temperature will be described with reference to FIG. explain.

  Here, Fig.3 (a) is a graph which illustrates transition of the internal temperature by the power consumption control method in one embodiment of this invention, FIG.3 (b) is one embodiment of this invention. It is a comparison figure which illustrates load operation time by a power consumption control method.

  When the set temperature is determined, an upper limit temperature and a lower limit temperature for the set temperature are set, and control is performed so that the internal temperature detected by the temperature sensor falls within the upper limit temperature and the lower limit temperature. Here, according to the conventional method, the difference between the set temperature and the upper limit temperature and the difference between the set temperature and the lower limit temperature are constant (1.5 degrees in the example of FIG. 3). Therefore, according to the prior art, the internal temperature is as indicated by the alternate long and short dash line in FIG. That is, when the upper limit temperature is reached, the load is changed from “stop” to “run”, and when the lower limit temperature is reached, the load is changed from “run” to “stop”.

  However, in this embodiment, the difference between the set temperature and the upper limit temperature is as described above, but the difference between the set temperature and the lower limit temperature is set smaller (1.0 degree in the example of FIG. 3). . If it does in this way, in control centering on the present preset temperature, load will change from operation to stop early, and it can control power consumption by load that much. In other words, in the prior art, what was cooled too much near the lower limit temperature is rounded up earlier in this embodiment, and the power consumption is reduced accordingly. FIG. 3B shows a comparison of the operation times of the conventional technique (one-dot chain line) and the present embodiment (solid line) side by side. According to this, it will be understood that according to the present embodiment, the sum of operation time is less than that of the prior art.

(Estimate)
According to the estimation of the present inventor, it was possible to reduce the power charge by about 10 to 25%. Details are as follows. For example, in the case of a chiller equipment user with a contract power of 500 kVA, if the basic charge is 950,000 yen and the electricity usage charge is 22.3 million yen, the total is 3.18 million yen, 10% of 950,000 yen = 95,000 yen, 22.3 million 20% of the yen = 446,000 yen, a total of 541,000 yen can be reduced, and 6.49 million yen can be reduced in one year. However, this trial calculation is only an example, and the present invention is not limited to these numerical values.

  Next, a control program executed by the program controller 2 will be described in detail with reference to FIGS. Here, FIG. 4 is a flowchart showing each process of the power consumption control method according to the embodiment of the present invention, and FIG. 5 is a set temperature profile determination process of the power consumption control method according to the embodiment of the present invention. It is a flowchart which shows.

  In step 1 of FIG. 4, if the set temperature profile is not yet determined, default values are set for the times t1 to t6 and the set temperatures T0 to T3. Next, unless the process is terminated in step 2, the process moves to step 3.

  In step 3, an initial value “1” is assigned to the counter i for identifying the load, and the current time supplied by the timer 4 is referred to in step 4 and subsequent steps.

  If it is time t6 (steps 4 and 5), it is the time to determine the set temperature profile for tomorrow, so that profile is determined in step 6. Specifically, as shown in FIG. 5, the power history stored in the history storage unit 6 is referred to (step 61), the normal set temperature T0 is determined (step 62), and the peak time period (t3, t4) is determined. ), The set temperature T3 is determined (step 63), the preceding cooling time zone (t2), the set temperature T2 is determined (step 64), and other times t1, t5, and t6 are determined (step 63). Information regarding these is stored in the profile storage unit 5. Then, the process moves to step 7.

  If it is after time t5 and not time t6 (steps 4 and 5), the set temperature is set to the set temperature T1 stored in the profile storage unit 5 in step 7, and the process proceeds to step 13.

  If the time is t1 to t2 or t4 to t5 (steps 4 and 8), the set temperature is set to the normal set temperature T0 stored in the profile storage unit 5, and the process proceeds to step 13.

  If it is the preceding cooling time zone (steps 4, 8, 10, 5), the set temperature is set to the set temperature T2 stored in the profile storage unit 5 in step 11, and the process proceeds to step 13.

  Alternatively, if it is a peak time zone (steps 4, 8, 10, 5), the set temperature is set to the set temperature T3 stored in the profile storage unit 5 in step 12, and the process proceeds to step 13.

  In step 13, the current operating state of the load related to the counter i is checked. If it is in the “running” state, the temperature di of the load related to the counter i is checked in step 14. If the temperature di is smaller than “set temperature −1”, the operation / stop signal ci related to the counter i is set to “stop” (step 15). Otherwise, the operation / stop signal ci related to the counter i is “ Driving ".

  If the current operating state of the load related to the counter i is “stop” in step 13, the temperature di of the load related to the counter i is checked in step 17. If the temperature di is greater than “set temperature +1.5”, the operation / stop signal ci related to the counter i is set to “operation” (step 19). Otherwise, the operation / stop signal ci related to the counter i is “Stopped”.

  When the above processing is completed, the current power state is stored in the history storage unit 6 in step 20. Then, in step 21, it is checked whether the counter i is equal to “n”. If it is not equal, the counter i is advanced by “1” in step 22, and the process proceeds to step 4. If they are equal, the process proceeds to step 2 as it is.

The block diagram of the cooling system using the power consumption control apparatus in one embodiment of this invention (A) The graph which illustrates the transition of the electric power by the power consumption control method in one embodiment of the present invention (b) The time chart which illustrates the transition of the set temperature by the power consumption control method in the one embodiment of the present invention (A) The graph which illustrates transition of the internal temperature by the power consumption control method in one embodiment of the present invention (b) The comparison figure which illustrates the load operation time by the power consumption control method in one embodiment of the present invention The flowchart which shows each process of the power consumption control method in one embodiment of this invention The flowchart which shows the setting temperature profile determination process of the power consumption control method in one embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control unit 2 Program controller 3, 11, 21, n1 Temperature sensor 4 Timer 5 Profile memory | storage part 6 History storage part 7 Network 8 External personal computer 10, 20, n0 Refrigerator 12, 22, n2 Temperature controller 13, 23, n3 start / stop circuit

Claims (6)

A power consumption control device connected to a control unit for inputting a demand signal and controlling operation / stop of a plurality of loads controlled by the control unit according to a set temperature profile,
The power consumption control device includes a profile storage unit that stores the set temperature profile,
The set temperature profile stored in the profile storage unit includes a first set temperature in a peak time zone where power consumption reaches a peak and a second setting in a preceding cooling time zone set immediately before the peak time zone. A temperature and a normal set temperature in a time zone that is neither the peak time zone nor the preceding cooling time zone,
Mean value of the first set temperature, the higher than normal set temperature, and the mean value of the second set temperature, rather lower than the normal set temperature,
Each of the plurality of loads includes a temperature sensor that detects the temperature of each load,
The power consumption control device, when the temperature of each load detected by the temperature sensor centered on the current set temperature defined by the set temperature profile is higher than the current set temperature by a first temperature range, Command each load to operate,
The power consumption control device, when the temperature of each load detected by the temperature sensor centered on the current set temperature defined by the set temperature profile is lower than the current set temperature by a second temperature range, Command each load to stop,
Moreover, the power consumption control apparatus is characterized in that the second temperature range is set narrower than the first temperature range . The power consumption control apparatus according to claim 1, further comprising a history storage unit that stores a current power consumption state, wherein the set temperature profile is determined with reference to a history of the power consumption state stored in the history storage unit. . 3. The power consumption control device according to claim 1, wherein the set temperature profile includes a set temperature that is set higher than the normal set temperature in night and morning time zones. Provided with a temperature sensor for detecting the temperature of the cooling target , a plurality of loads for cooling each cooling target,
A control unit for inputting a demand signal and controlling the plurality of loads;
A power consumption control device connected to the control unit and controlling operation / stop of a plurality of loads controlled by the control unit according to a set temperature profile,
The power consumption control device includes a profile storage unit that stores the set temperature profile,
The set temperature profile stored in the profile storage unit includes a first set temperature in a peak time zone where power consumption reaches a peak and a second setting in a preceding cooling time zone set immediately before the peak time zone. A temperature and a normal set temperature in a time zone that is neither the peak time zone nor the preceding cooling time zone,
The average value of the first set temperature is higher than the normal set temperature, and the average value of the second set temperature is lower than the normal set temperature,
The power consumption control device, when the temperature of each load detected by the temperature sensor centered on the current set temperature defined by the set temperature profile is higher than the current set temperature by a first temperature range, Command each load to operate,
The power consumption control device, when the temperature of each load detected by the temperature sensor centered on the current set temperature defined by the set temperature profile is lower than the current set temperature by a second temperature range, Command each load to stop,
Moreover, the cooling system is characterized in that the second temperature range is set narrower than the first temperature range. Storing the current power consumption state;
Referring to the accumulated power consumption history, a peak time zone in which power consumption reaches a peak and a preceding cooling time zone immediately before the peak time zone are determined, and a first set temperature in the peak time zone And the second set temperature in the preceding cooling time zone, the average value of the first set temperature is higher than the normal set temperature, and the average value of the second set temperature is the normal setting Determining to be lower than the temperature and setting a set temperature profile;
See containing and controlling the operation / stop of a plurality of loads in accordance with the set temperature profile,
When the temperature of each load is higher than the current set temperature by a first temperature width centered on the current set temperature defined by the set temperature profile, the load is commanded to operate.
When the temperature of each load is lower than the current set temperature by a second temperature width around the current set temperature defined by the set temperature profile, the load is ordered to stop.
Moreover, the power consumption control method is characterized in that the second temperature range is set narrower than the first temperature range . The power consumption control method according to claim 5 , wherein the set temperature profile includes a set temperature that is set higher than the normal set temperature in night and morning time zones.

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